EPA 744-R-98-OO5 COMPUTER DISPLAY INDUSTRY AND TECHNOLOGY PROFILE ------- ACKNOWLEDGEMENTS This document was prepared by Colleen Mizuki and Gloria Schuldt of Microelectronics and Computer Technology Corporation (MCC) as part of the collaborative Design for the Environment (DfE) Computer Display Project. The Project Officer for this grant was Kathy Hart of EPA's DfE Program, in the Office of Pollution Prevention and Toxics. This report would not have been possible without the assistance of the industry members who supplied information for this report. DfE Computer Display Project Core Group members provided valuable guidance and feedback during the preparation of this report. Core Group members include: Kathy Hart (Core Group Co-Chair), EPA; David Isaacs, Electronic Industries Alliance (Core Group Co-Chair); Dipti Singh, EPA (Technical Workgroup Co-Chair); Ross Young, DisplaySearch (Technical Workgroup Co-Chair ); Lori Kincaid and Maria Socolof, University of Tennessee Center for Clean Products and Clean Technologies; Greg Pitts, Colleen Mizuki, and Gloria Schuldt, MCC; John Lott, DuPont Electronics; Jeff Lowry, Techneglas; Frank Marella, Sharp Electronics Corporation; Bob Pinnel, U.S. Display Consortium; Doug Smith, Sony Corporation; Ted Smith, Silicon Valley Toxics Coalition.; Dan Steele, Motorola; and David Thompson, Matsushita Electronic Corporation of America. We also thank the other industry representatives and interested parties who reviewed and provided suggestions for this report. Industry representatives include: Rich Beer, Lam Research Corporation; Robert Conner, Applied Komatsu Technology; Paul Semenza, Stanford Resources, Inc.; Bill Simpson, Corning; Curt Ward, Candescent Technologies Corporation; and Jeff Zeigler, R. Frazier, U.S. ------- TABLE OF CONTENTS 1.0 INTRODUCTION 1 2.0 INDUSTRY MARKET PROFILE 2.1 COMPUTER MONITORS : VOLUME AND TECHNOLOGY TRENDS 3 2.1.1 CRTs 3 2.1.2 LCDs 4 2.2 MANUFACTURING LOCATIONS AND SUPPLIERS 6 2.2.1 CRTs 6 2.2.2 CRT materials and subassemblies 9 2.2.3 LCDs 10 2.2.4 LCD materials and subassemblies 11 3.0 TECHNOLOGY PROFILE 12 3.1 CRT OPERATION AND COMPONENTS 12 3.2 CRT MANUFACTURING PROCESS 14 3.2.1 CRT glass fabrication 15 3.2.2 Faceplate preparation (pattern) 15 3.2.3 Shadow mask fabrication and assembly to faceplate 17 3.2.4 Funnel preparation 18 3.2.5 Bulb joining 18 3.2.6 Electron gun fabrication and assembly 19 3.2.7 Final assembly 19 3.3 ACTIVE-MATRIX LCDs 21 3.3.1 Thin-film transistor (TFT) structures 21 3.3.2 Twisted-nematic TFT-LCD operation 22 3.4 TFT-LCD MANUFACTURING 24 3.4.1 Glass fabrication 24 3.4.2 Front panel patterning 25 3.4.2.1 Deposit ITO 25 3.4.2.2 Pattern color filter 25 3.4.2.3 Deposit alignment layer 26 3.4.2.4 Inspect and test 26 3.4.3 Rear Panel Patterning 26 3.4.3.1 Clean and inspect 26 3.4.3.2 Pattern TFTs 28 3.4.3.3 Deposit passivation layer/test/inspect 29 3.4.3.4 Deposit alignment layer 29 3.4.4FrontPanelPatterning-IPS 29 3.4.5 Rear Panel Patterning-IPS 29 3.4.6 Display cell and final module assembly 31 3.4.6.1 Seal panels 31 3.4.6.2 Inject LC 32 3.4.6.3 Attach polarizers 32 3.4.6.4 Inspect and test 32 3.4.7 Module Assembly 32 3.4.7.1 Attach backlights 32 3.4.7.2 Attach electronics 32 3.4.7.3 Final test and ship 33 APPENDIX A 34 FLAT PANEL DISPLAY TECHNOLOGIES 34 ------- APPENDIX B 39 CRT MANUFACTURE 39 APPENDIX C 42 NEC CRT: DETAILED BILL OF MATERIALS 42 APPENDIX D 46 TFT-LCD MANUFACTURE 46 Glass Panel 46 Front Panel Pattern-TN 47 Rear Panel Pattern-TN 49 Front Panel Pattern-IPS 52 Rear Panel Pattern-IPS 53 Display Cell Assembly 55 Display Module Assembly 56 APPENDIX E 57 CANNON FPD: DETAILED BILL OF MATERIALS 57 GLOSSARY 65 ill ------- Computer Display Industry and Technology Profile 1.0 Introduction Since World War II, cathode ray tube (CRT) electronic displays have played an increasingly important role in our lives, with televisions and personal computers being the primary applications. In the 1970's, the liquid crystal display (LCD) became popular in wristwatches and calculators. In the early 1980s, Epson introduced the first portable computer with a monochrome LCD display, followed soon by LCD monitor displays from Tandy and Toshiba. These electronic displays are commonly referred to as flat panel displays (FPDs). There are now a number of flat panel displays (FPDs), each providing particular advantages for a given application. Appendix A1 provides an overview of LCD and other FPD technologies. The LCD is by far the most common type of FPD, and currently is the only FPD used in commercial computer monitors, which includes laptop monitors. Computer monitors constituted approximately 54.7 percent of the $13.9 billion LCD market in 1997, and are predicted to increase to 67.4 percent of the $31.5 billion market in 2001.2 LCDs comprised 87.6 percent of all FPD applications in 1997, and are expected to drop only slightly to 85.8 percent in 2003.3 LCDs have greatly increased in number, type, and applications, including growth in the desktop monitor application. LCD desktop monitors, although not yet numerous in the commercial sector, appear to be a likely replacement technology for CRTs. Therefore, the potential for high market penetration and an increased LCD material volume is significant. Concern over the environmental impact associated with the manufacture, use, and disposition of electronic products has emerged in recent years. These concerns have been driven in part because computer manufacturing requires the use of some toxic materials that may pose occupational and environmental risks. Concern has also been raised by the 1 Socolof, M.L., et al., Environmental Life-Cycle Assessment of Desktop Computer Displays: Goal Definition and Scoping, (Draft Final), University of Tennessee Center for Clean Products and Clean Technologies, July 24, 1998. 2 Stanford Resources, presentation at the 1998 United States Display Consortium (USDC) Business Conference, San Jose, CA. 3 Ibid. ------- growing numbers of consumer electronic products in the marketplace, creating an increasing volume of end-of-life (EOL) materials and some calls for changes in EOL management, especially in Europe. Producers, customers, legislators, regulators, and municipalities are interested in examining the resources used to produce and use these products, and in reducing environmental impacts throughout the entire computer product life cycle, especially during disposition at EOL. In the consumer realm, CRT displays in televisions and computers dominate in terms of material volume, while LCDs found in household equipment (e.g., microwaves, stereos) and consumer items (e.g., watches, cell phones, pagers) dominate in terms of number of displays. Looking at all electronic displays in terms of material volume, it is helpful to analyze three categories separately. The largest displays (>40-inches) are generally in projection format, and thus consume relatively small material volumes; they are also produced in relatively small unit volumes. The smallest displays (<5-inches) are produced in large volumes (over 1.6 billion units in 1998), but tend to be part of larger systems (appliances, stereos) and so are a relatively small part of the overall material volume. It is in the middle sizes (5- to 40-inches) that the display material volume is a large fraction of the system, and unit volumes are significant. In order to assess environmental impacts of both CRTs and LCDs during manufacturing, use, and disposition stages, the United States Environmental Protection Agency Design for the Environment (DfE) Program formed a voluntary partnership with the display industry. The goal of the DfE Computer Display Project is to study the life cycle environmental impacts of CRT and LCD desktop computer displays, and generate data that will assist the display industry to make environmentally informed decisions and identify areas for improvement. The selection of these two types of displays was based on potential end-of- life material volume, widespread use, and the ability to compare two display types with the same functional unit—desktop computer application. The purpose of the Computer Display Industry and Technology Profile is to provide an overview of the CRT and LCD computer monitor markets and technologies. Section 2.0 presents a market profile based on currently available data. The profile is not an exhaustive market assessment, and does not intend to imply preference to one technology type. Section 3.0, Technology Profile, presents an explanation of the basic operation and manufacturing of CRTs and thin-film transistor (TFT) -LCDs to readers relatively unfamiliar with the topic. ------- 2.0 Industry Market Profile 2.1 Computer Monitors: Volume and Technology Trends Virtually a one-to-one ratio exists between the number of computers and the number of displays in the marketplace. Because the world market for computers has grown so rapidly, a corresponding increase in displays can also be expected. Sales of personal computers (PCs) are expected to continue to grow beyond the year 2000. Many PCs will be desktop systems. ADI Corporation estimated worldwide demand for PCs at 66 million units in 1996, growing to 86.63 million in 1998, and over 100 million in 2000.4 Desktop applications make up most of these sales. The United States has been a major market for computers. The U.S. Bureau of the Census estimates that in 1993, 43.2 percent of the U.S. working population used a computer at work, compared with 34.8 percent in 1989 and 23.2 percent in 1984. Also in 1993, 22,605,000 households owned a home computer, up from 13,683,000 in 1989, and 6,980,000 in 1984.5 2.1.1 CRTs The computer monitor has been one of the two largest applications for CRTs; the other has been television. According to a report published by Fuji Chimera Research, the 1995 worldwide market for monitor CRTs was 57.8 million units, 28 million of which (48.5 percent) were consumed in North America.6 According to the same source, 1996 worldwide CRT monitor demand increased to 67.1 million units.7 Stanford Resources reports that the CRT monitor market reached 84.2 million units in 1997 (25.6 million in the United States), and anticipates a worldwide growth to more than 100 million units in 2002, reaching 113.5 million in 2003.8 4 Nikkei Microdevices' Flat Panel Display 1997 Yearbook, Nikkei Business Publications, Inc., p. 98. 5 "Computer Use in the United States: October 1993," U.S. Bureau of the Census, Current Population Reports, Special Series P-23. " The Future of Liquid Crystal and Related Display Materials, Fuji Chimera Research, 1997, p. 12. 7 Ibid. Stanford Resources, Inc., web site. ------- In order to keep pace with more demanding computer applications, CRTs have been continually improved: larger screen sizes, higher resolution (for Windows, Macintosh OS, and Web-page font challenges), and higher luminance (for videos). This improvement is likely to continue, as the market moves away from sales of smaller (14-inch and 15-inch) monitors, toward 19-inch and 21-inch monitors. Features that were once accompanied by a high price tag are becoming more standard. Reduced dot pitch; color matching; flatter, lighter weight, touch-sensitive screens; and digital cameras are some of the new offerings at lower prices. This is due, in part, to an increased number of CRT suppliers in the marketplace and improvements in technologies, such as aperture grille, Invar shadow mask, and the flatter Trinitron CRT. The marketplace is seeing other changes in CRTs, such as shorter necks that reduce the depth by at least three inches on a 17-inch monitor. Display Search reports that while a wider deflection yoke angle enables this development, it causes problems with focusing, which may require more circuitry to resolve. A number of companies have recently released new monitors, many in the 17-inch and 19-inch range. 2.1.2 LCDs Although market analysts predict growth in the CRT monitor market through the first few years of the 21st century, it is widely anticipated that after that point, LCDs will begin to erode the CRT stronghold. Although the portable computer is currently the major application for LCDs, industry analysts expect this technology to increasingly penetrate the desktop monitor market, particularly in the 15-inch to 20-inch range. Industry experts anticipate that by 2000, LCDs will have captured 5.4 percent of the monitor market. The United States is a primary market for LCD monitors, and will grow into an even stronger market by the end of the century. NEC estimates that the United States will receive over half of the forecasted 6.4 million LCD monitors shipped in 2001 (see Figure 2-1). Display Search also forecasts that the United States will constitute 30 percent of the worldwide LCD monitor market in 2001, with total LCD monitor sales of 7.7 million units. DisplaySearch predicts a worldwide LCD monitor market of $4.2 billion by 2000.9 DisplaySearch Monitor, April 1997. ------- (1,000 units/yr) 7000 T 6000- 5000- 4000- 3000- 2000- 1000- II Japan Europe North America 1997 1998 1999 2000 2001 Figure 2-1: LCD Monitor Forecast10 LCD monitors are primarily active-matrix LCD (AMLCD), most of which are thin-film transistor (TFT) structures. Super-twisted nematic (STN), a passive-matrix LCD (PMLCD) technology, competes in some areas with AMLCD. Although some monitors are based on an STN structure, STN-LCDs are primarily found in electronic organizers and measurement devices. While STN-LCDs offer a cost advantage over TFT-LCDs, prices for the latter technology have been dropping. DisplaySearch reports that the TFT market will grow from $4.87 billion in 1996 to $13.7 billion in 2000, whereas the STN market is expected to drop slightly from $4.3 billion to $4.2 billion during the same time period.11 At Computex Taipei '97, a leading computer exhibition, over 20 companies displayed more than 100 models of LCD monitors.12 A number of companies promoted both AMLCD and PMLCD monitors. More recently, DisplaySearch reported that over 180 LCD monitors are marketed by 50-some companies, 81 percent of which use thin-film TFT-LCD technology, 10 Nikkei Microdevices' Flat Panel Display 1998 Yearbook, Nikkei Business Publications, Inc., p. 80. 11 DisplaySearch Monitor, April 1997. Information Display, Official Publication of the Society for Information Display, October 1997, p. 37. ------- and 19 percent of which use STN technology.13 According to Display Search, TFT-LCD monitor shipments will grow from 1.1 million in 1998 to 13.1 million in 2002.14 Between 1998 and 2001, the 15-inch display is expected to make up the greatest share of these monitors.15 Currently, the greatest obstacle facing LCDs in the desktop monitor market is not competition from other LCD technologies, but a high price tag relative to that of CRTs. TFT-LCD monitors currently cost several times that of a CRT monitor, with a 15-inch unit costing $1200. There are indications that the price of TFT-LCDs will continue to decrease, prices have already dropped to $900. Most of the LCD monitor sales have been to the medical and financial community, but expectations are that the customer base will spread when a 3:1 cost ratio with CRTs is reached, and even more so as prices continue to decline. Surveys indicate that given a 1.5:1 cost ratio of FPDs to CRTs, 30 percent of consumers would opt for the FPD. DisplaySearch reports that low prices by Korean LCD suppliers will likely bring prices of 15- and 18-inch LCD monitors down to a 2X price ratio with 17" and 19" CRTs by the end of 1998. 2.2 Manufacturing Locations and Suppliers 2.2.1 CRTs The majority of CRT display fabrication takes place outside of the United States. In 1997, Asia (excluding Japan) produced 54 percent of all color TVs and 79 percent of all CRT monitors.16 DisplaySearch reports that Japan supplies between 10 and 15 percent of CRTs produced worldwide, primarily 17-inch and larger. The greatest concentration of CRT manufacturers is in Taiwan, where 33.6 percent of total world production took place in 1996.17 South Korea and China are also becoming major sites for CRT monitor production. Most color CRT monitors and small TV CRTs (less than 19 inches) are produced outside the United States. Due to the cost of transporting heavier displays, some TV CRTs, 19 inches and larger, are produced in the United States. It is possible that a 13 Presentation by DisplaySearch at the USDC Business Conference: Enabling New Display Markets, Display Works, January 20, 1998, San Jose, CA. 14 DisplaySearch FPD Equipment and Materials Analysis and Forecast, Austin, Texas, June 1998. 15 Ibid. 16 The Future of Liquid Crystal and Related Display Materials, Fuji Chimera Research, 1997, p. 12. Stanford Resources, Inc., web site. ------- similar situation will arise with larger CRTs monitors.18 See Table 2-1 for regional production figures for CRT monitors. 1994 Europe North America Asia Japan So-Central America Total 3,500 800 41,000 5,300 800 51,400 1995 3,850 1,000 45,650 6,080 1,200 57,780 1996 4,300 1,200 53,000 7,100 1,500 67,100 1997 4,800 1,500 60,000 8,000 1,900 76,200 1998 2000 5,300 1,800 65,000 9,000 2,500 83,600 6,000 2,400 75,000 10,000 3,200 96,600 Table 2-1: Color CRT Monitors Production by Region (,000 units)19 As is the case with most commodity goods, CRT monitors are distributed by the manufacturer via different routes. They may be sold under the manufacturer's name through retail channels, or to original equipment manufacturers (OEMs) or other system retailers, such as Dell Computers. Major manufacturers and retailers include Acer, Apple, Compaq, CTX, Dell, Digital, Eizo, Hitachi, Hewlett Packard, IBM, liyama, LG, MAG, Mitsubishi, NEC, Nokia, Panasonic, Samsung, Sharp, Siemens Nixdorf, Sony, Toshiba, and Viewsonic. Figure 2-2 shows the 1997 market share in the United States per CRT monitor brand name. In this table, some manufacturers (such as Sony) will be under-represented, as the monitors they manufacture for other companies may carry the brand name of the other company (e.g., Sony monitors manufactured for Dell). Figure 2-3 provides data on the 1996 industry market share for main color CRT monitor-tube manufacturers. 18 Reported at the Glass Roundtable meeting, February 6, 1997, University of Texas at Austin. The Future of Liquid Crystal and Related Display Materials, Fuji Chimera Research, 1997. ------- 1 0 6 2 I — | H6 Compaq Dell Packard Gateway IBM ViewSonic NEC Bell 2000 CRT Brand Name = CTX Sony t Acer Figure 2-2: CRT U.S. Market Share (Percent) by Brand Name20 25 20 15 10 5 Hitachi Sony Samsung Chunghwa Matsushita Toshiba Tube Manufacturers Philips Lucky Goldstar Figure 2-3: Worldwide Market Share (Percent) of Color CRT Tube Manufacturers21 Source: Stanford Resources, 1997 data. Source: Stanford Resources, 1996 data. ------- 2.2.2 CRT materials and subassemblies The majority of CRTs (TVs and monitors) and CRT-related components and materials are manufactured outside of the United States. The major materials, components and subassemblies are as follows: • Faceplate • Shadow mask assembly • Funnel • Electron gun assembly • Neck • Deflection yoke • Phosphors • Deflection amps • Frit • Centering magnets • Aquadag • Printed wiring boards (PWBs) • Lacquer coating • Anti-static/anti-glare coating For a more extensive listing, see the CRT process flow and bill of materials in Appendices A and B, respectively . There are approximately 100 CRT manufacturers worldwide.22 In the United States, there are five CRT glass manufacturing plants, producing approximately 600K tons of product annually: Thomson, Techneglas (two sites), and Corning (three sites, with one being a joint venture with Sony). Glass is imported from Asahi, NEC, Samsung, Schott, and Philips. Sony is the only manufacturer of color monitor tubes in the United States, although they, along with Hitachi, Matsushita, Philips, Thomson, Toshiba, and Zenith, do produce TV- tubes in the United States. Aydin, Compaq, Display Tech, Digital Equipment Corporation, IBM, Modicon, NCR, and Unysis assemble computer displays domestically. Techneglas, in addition to being a major North American manufacturer of panel and funnel glass, is a large producer of frit, planar dopants, and glass resins. Phosphors are supplied internally from vertically integrated manufacturing facilities and by foreign manufacturers (primarily in Japan). Electronic Engineering Times, December 1, 1997, num. 983, p. 27. ------- The remainder of the components and subassemblies are produced primarily in Asia. Although shadow masks for TVs are produced in United States, no United States manufacturer has established a high-volume, high-resolution shadow mask facility for monitors. Nippon Printing and Dai Nippon Screening are primary producers in Asia. Electron guns are made from precision metals parts, a significant portion being manufactured by Premium Allied Tube. Insulator glass used in the gun assembly is supplied by Corning Asahi Video and Techneglas. Deflection yokes and amps are produced primarily in the United States, Canada, and Taiwan, and there are a couple of domestic producers of centering magnets. 2.2.3 LCDs The number of LCD suppliers is significantly lower than the number of CRT suppliers, primarily due to the high capital cost of manufacturing FPDs. As shown in Figure 2-4, Japan leads in AMLCD investment, followed by South Korea. More recent data from DisplaySearch shows that LCD capital investment by Japanese and Korean companies will decrease significantly in 1998 to $676 million, down from $3.85 billion the previous year. Taiwan $400 Europe $350 United States $250 Source: POSTECH Figure 2-4: Capital Investment in AMLCD Production 1994-1996 (Smillions) 10 ------- In 1995, Japan manufactured 94.7 percent of all LCDs, followed by Korea at 3.5 percent and Taiwan at 1.7 percent; 0.1 percent were produced outside of these regions. By 2005, Japan is forecasted to lead LCD production, with 75 percent. Korea is expected to increase its share to 12.9 percent, and Taiwan to 11.9 percent; 0.2 percent will be produced elsewhere. Korean and Taiwanese LCD manufacturers have been able to enter this market partially due to strategic relationships with Japanese companies. Samsung Electronics has established technical cooperation with Fujitsu for TFT-LCDs. LG (Lucky Goldstar) Electronics jointly developed technology with Alps Electric. CPT is in technical cooperation with Mitsubishi for TFT-LCDs. Chunghwa Picture Tubes has a partnership with Toshiba for STN-LCDs and is searching for a partner in TFT development. In addition, IBM and Acer are working together on TFTs, as are Toshiba and Walsin Linwa. 2.2.4 LCD materials and subassemblies The LCD manufacturing process, particularly for TFT-LCD, is more complex in terms of types of materials and process steps than is the CRT process. The following list has been abbreviated to provide only the major materials, components, and subassemblies. For a more complete listing, refer to Appendices C and D for the TFT-LCD process flow and bill of materials, respectively. • Front glass panel • Photoresists • Col or filter materials • Developing solution • Indium tin oxide • Sealer • Back glass panel • Spacers • Liquid crystal materials • Polarizing material • Transistor metals • Driver ICs • Alignment material • Backlight units • Etchants • PWB Almost all of the materials, components, and subassemblies for LCD monitors are made in Asia. The exceptions are backlights and some driver integrated circuit (1C) devices, which are produced in North America or Europe. 11 ------- 3.0 Technology Profile 3.1 CRT Operation and Components The cathode ray tube (CRT), whose basic components are shown in Figure 3-1, uses high voltages to move electrons toward a display screen. The electrons are emitted from a cathode and concentrated into a beam with focusing grids. The beam is accelerated toward the screen, which acts as an anode, due to a conductive coating. The screen is also coated with a luminescent material (a phosphor), typically zinc sulfide. This phosphor converts electromagnetic radiation (the kinetic energy of the electrons) into light—a phenomenon called phosphorescence.23 The cathode ray is essentially an electric discharge— the stream of electrons— in a vacuum tube. The beam passes through either horizontal and vertical deflection plates (mutually perpendicular pairs of electrodes) or magnetic deflecting coils in the deflection yoke. Voltage is applied to these plates (or coils) to control the position of the beam and its line- by-line scanning across the screen. Video signal (information to be displayed on the screen) is applied to the electrode (cathode) and is contained in the electron beam. This video signal, which controls the current to the electron-beam, is applied in synchronization with the deflection signals. The result is two-dimensional information displayed on the screen. The materials that phosphoresce are referred to as phosphors. Phosphors do not contain phosphorous. 12 ------- Or.d1 Del lea ion Hard vacuum Figure 3-1: Cathode Ray Tube Fundamentals Color images are made possible through several techniques. The most common technique is the use of a shadow mask, widely used in consumer TVs and monitors (see Figure 3-2). This technique requires three electron guns, which emit electrons that then pass through an aperture—a shadow mask—before hitting the screen. Different phosphorescing colors are obtained by adding materials to the zinc sulfide coating on the screen. The beam impacts the screen at precise locations, striking only one of three colored regions: a red, green, or blue area, and emits visible light. When this point source of light strikes the corresponding dot, a shadow of the mask falls on the inside of the screen. The three beams are controlled (deflected) by one yoke, enabling the three beams to strike the corresponding dots simultaneously, and requiring only one focus control. 13 ------- DTJl.E4.11tf> UJD BEAM DOT PITCH GRKKN PHOSPHOR SCREEN Figure 3-2: Shadow Mask Color CRT24 The most common alternative to the shadow-mask technique is the Trinitron, which uses an aperture grill (rather than a shadow mask) that is composed of parallel, colored stripes, (rather than dots). A grid positioned in front of the stripes directs the beam to the appropriate color. Although the Trinitron design offers certain performance and warrants investigation, the scope of this operational and manufacturing description is limited to the shadow mask structure. 3.2 CRT Manufacturing Process25 The traditional CRT glass manufacturing process is comprised of the following main categories of activities: • Glass fabrication • Faceplate (screen) preparation • Shadow mask fabrication/assembly • Funnel preparation Castellano, LA.,Handbook of Display Technology, Academic Press, Inc., 1992, pg. 42, •" Environmental Consciousness: A Strategic Competitiveness Issue for the Electronics and Computer Industry, MCC, 1993. 14 ------- • Bulb joining • Electron gun fabrication • Final assembly 3.2.1 CRT glass fabrication Raw materials are converted to a homogeneous melt at high temperatures and then formed into the glass panel (see Figure 3-3). Sand is the most common ingredient and must be chosen according to high quality, high purity, and grain-size standards. The sand and soda ash can be sourced within the western United States, whereas limestone may come from the coast of the Bahamas. Other raw materials such as boron (used as anhydrous borax or boric acid) come from California or Turkey. Dry blending mixes the raw materials, and small amounts of liquid may be added for wet blending. The batch is then preheated to temperatures approaching that of the furnace and charged into the furnace, where melting and other reactions (dissolution, volatilization, and redox) take place. The next phase, fining, removes bubbles chemically and physically from the molten glass melt. The most commonly used fining agents are sulfates, sodium or potassium nitrates, and arsenic or antimony trioxides. The melt is then conditioned, or homogenized, and then cooled prior to fabrication. After forming, the glass must be prepared to withstand upcoming chemical, thermal, and physical activities and to meet high quality standards for optical glass. These activities include some, or all, of the following: beveling, chamfering, grinding, polishing, and annealing at 350-450 degrees Celsius. In some cases, breakage occurs during the manufacturing process, in which case the broken glass—cullet—can be reintroduced into the batch melt. 3.2.2 Faceplate preparation (pattern) The CRT faceplate, also referred to as a panel or screen, is coated with a conductive material and a luminescent material (the phosphors). The conductive coating, an aquadag, acts as an anode, attracting the electrons emitted from the electron guns. The coating is composed of electrically conductive carbon particles, with silicate binders suspended in water. It is deposited by painting, sponging, spinning, or spraying, and then baked to increase durability. 15 ------- Glass sand SiO2 Soda ash Na2CO3 Limestone CaCO2 Feldspar Batch mixing Melt 1500C Fine 1550C Condition 1300C Form 800-1100C Inspect and test product Ship Other (K2O, MgO, ZnO, BaO, PbO (fining, coloring, oxidizing) Crush cullet Figure 3-3: Glass Manufacturing Process Flow26 26 Encyclopedia of Chemical Technology, 3rd Edition, vol 11, 1980, p. 847. 16 ------- The luminescent phosphor and contrast-enhancing materials are applied to the inside surface of the faceplate in aqueous solutions, using spin coaters. These coatings are patterned by photolithography, using polyvinyl alcohol (PVA) photoresists and near-ultra- violet exposure lamps. Exposure of the photoresist material from light passing through the apertures in the shadow mask creates a pattern of dots (or stripes) where the red, green, and blue phosphors will be placed in subsequent steps. These phosphor materials are powders that are applied one at a time in dichromate-sensitized PVA slurries (a thin paste that has solids suspended in liquids). The pattern is developed by rinsing with a solvent to wash away the unexposed resist. Next, a coating of contrast-enhancing material (grille dag) is applied and dried. A lift-off process digests the resist that remains between the glass and the grille material. The digested resist lifts off the glass, carrying away unwanted grille material on top of it and opening windows in the black grille material. In subsequent coating and photolithographic steps, the red, green, and blue phosphors are deposited in these windows. The result is a patterned luminescent screen with the emissive elements separated by the non-reflecting grille material. The grille dag and phosphor deposition processes leave a non-uniform screen surface. To level this surface, lacquer is applied as an extrusion film, or it is sprayed onto the screen and then dried. A layer of aluminum is then evaporated onto the screen to enhance reflection. 3.2.3 Shadow mask fabrication and assembly to faceplate The shadow mask foil is a thin structure made of aluminum-killed steel that is etched with the appropriate pattern of round apertures (may also be slits or slots). It is patterned through a series of photolithographic steps. The mask foil is coated with a casein type resist (a food industry by-product) and exposed with ultraviolet (UV) lamps. The design is developed and the apertures etched away with a ferric chloride solution.27 The ferric chloride etchant is reduced by the dissolving iron, producing ferrous chloride from both the etchant and the dissolving iron. The etchant is regenerated using chlorine, producing by-product chemicals and ferric chloride. The etch process for monitors takes place in Europe or the Pacific-Rim countries. No United States manufacturer has established a high volume, high-resolution shadow mask etching facility. 17 ------- The mask, which is flat when delivered to the CRT manufacturer, is first curved to approximately the shape of the faceplate in a large hydraulic press. In the CRT, it is supported on a heavy frame, which is typically manufactured by metal cutting, welding and stamping. Springs are welded to the formed frame and the shadow mask is welded on while the parts are held in an alignment fixture. The parts are then oven-blackened to increase the brightness capability of the finished CRT. 3.2.4 Funnel preparation The funnel provides the back half of the vacuum shell and electrically connects the electron gun in the neck of the CRT and the faceplate to the anode button (a metal connector button in the funnel provided for attachment of the power supply). The conductive coating on the inner surface is an aquadag; similar to the type used on the screen. The major difference is the graphite particle size and the addition of electrical conductivity modifiers. Silicate binder concentration may be higher, and iron oxide may be added, to reduce the conductivity. Funnel dag is applied by sponge, flow coating, or spraying, and is then baked to evaporate the solvent in the dag. The surface of the dry funnel that will be mated with the faceplate (screen, panel) is coated with a frit (solder glass). This frit is a low melting temperature glass powder made of lead oxide, zinc oxide, and boron oxide, which is mixed with nitrocellulose binder and amyl acetate vehicle to form a paste (with the consistency of toothpaste). It is typically formulated so that the final melting temperature is significantly higher than the original melting temperature, thereby allowing it to be reheated in repair and recovery processes. 3.2.5 Bulb joining The panel and shadow mask assembly and internal magnetic shield are joined together by clips to form a faceplate assembly. This assembly is placed on the fritted funnel in a fixture that carries the two halves in precise alignment through a high temperature oven, where the frit is cured (hardened). The resulting assembly is a vacuum tight bulb, ready to receive the electron gun and to be evacuated to become a finished CRT. 18 ------- 3.2.6 Electron gun fabrication and assembly The electron gun is composed of a number of electrostatic field-shaping electrodes made of 300 and 400 series steels. These steels are similar to those used in other industries, but have higher purity requirements and contain iron (Fe), nickel (Ni), and chrome (Cr). The electron gun metals are typically annealed hydrogen fired before being assembled and attached to insulating glass support pillars. The pillars, made of a borosilicate glass, are heated to their softening temperature and pressed over tabs on metal electrodes. After the pillars cool, they captivate the electrodes, making a monolithic structure. This structure is mounted to a glass stem that will be joined to the neck portion of the bulb assembly by melting. The glass stem is provided with electrical feed-though pins, which carry the electrical connections from the external circuitry to the electrodes. Hidden within the lower end of the gun are three cathodes consisting of hollow nickel tubes, with one end closed and coated with an electron emitting material, typically a mixture of barium, strontium, and calcium carbonates. A tungsten wire heater, coated with a layer of insulating aluminum oxide, is placed in the center of the cathode tube. Additional ribbon conductors are welded between the upper electrodes and the remaining pins in the stem. Finally, the upper cup of the gun, steel centering springs, and a vacuum getter ring on a long wand are welded on. Additional parts are added at this stage, such as anti-arcing wires, magnet pole pieces, or magnetic shunts, depending upon the design. This finished electron gun assembly is ready for sealing to the bulb. 3.2.7 Final assembly The frit-sealed bulb assembly and the electron gun assembly are joined by fusing the stem and neck tubing together in a gun-seal machine that melts the two glasses together. During this fusing operation, the two pieces are fixtured into precise alignment. Typically, the neck is slightly longer than necessary and the excess glass is "cut off by the sealing fires, falls into a reclaim container, and is returned directly to a glass company to be remelted and reformed into a new neck. 19 ------- Figure 3-4: CRT Manufacturing Process 20 ------- After joining, the entire CRT is attached to a vacuum exhaust machine that carries the assembly through a high-temperature oven while exhausting the air from inside the CRT. The combination of high temperature while pumping the air out of the CRT produces a high vacuum inside. After cooling, the vacuum getter is vaporized and the evaporated metal (barium, zinc) coats the inside surface of the CRT. This film absorbs the residual gases inside the envelope and reduces the gas pressure inside the CRT to its final operating pressure. The electron emissive cathode material, which was initially sprayed on the nickel cathode cap as a carbonate, is first converted to an oxide by electrically heating the cathode to high temperature. The surface metal oxides are then reduced to a monolayer of metal by emitting an electrical current from the cathode while it is at high temperature. The resulting surface emits large quantities of electrons that can be controlled by voltages applied to the electrodes of the gun. The final CRT manufacturing stage is electrical test and visual inspection. Having passed these tests, the CRT faceplate is fitted with a steel implosion band for safety. The band compresses the CRT, thereby increasing the strength of the glass, making the tube more resistant to implosion. A flow-chart description of the CRT manufacturing process is shown in Figure 3-4.28 3.3 Active-Matrix LCDs 3.3.1 Thin-film transistor (TFT) structures Computer displays need very fast response speed, high contrast, and high brightness to handle the information content and graphic demands. One way to achieve this speed is by having a switch at each pixel, which is the basis for active-matrix addressing. This switch can be a transistor or a diode (Appendix A). This profile will cover only the transistor structure, which basically consists of a gate, source and drain, and channel. Electrons flow through the channel between the source and drain when voltage is applied to the gate. There is an insulating layer between the gate and the source/drain region, referred to as a dielectric. Socolof, M.L., et al., Environmental Life-Cycle Assessment of Desktop Computer Displays: Goal Definition and Scoping, (Draft Final), University of Tennessee Center for Clean Products and Clean Technologies, July 24, 1998. 21 ------- The transistors are patterned on the rear panel of the display, on a base of amorphous silicon (a-Si) or polysilicon (poly-Si). Currently, most flat panel displays (FPDs) use a-Si, although poly-Si does offer some performance advantages in smaller displays. These advantages have not overcome the fact that the technique for depositing thin-film a-Si is very well understood and established. Therefore, most TFT-LCDs are currently based on a-Si, which is the subject of this profile. TFT a-Si devices are typically characterized as staggered, which refers to the fact that the pixel electrodes are on opposite panels (one on the front and one on the rear). More recently, a new design has emerged in the marketplace, called in-plane switching (IPS). This profile will cover the manufacturing processes for the bottom-gate etch stop (E/S)—a staggered structure—and the in-plane switching (ISP) design. Most TFT-LCD monitors are based on the E/S transistor structure, although NEC and Hitachi have released monitors using IPS. 3.3.2 Twisted-nematic TFT-LCD operation Whereas the E/S or IPS designation relates to the addressing mechanism for each pixel, the principle behind light transmission of the display is related to characteristics of the liquid crystal (LC). This profile covers the operation of twisted nematic (TN) technology, which is used in most computer monitors. All LCDs work on the same principle: information on the screen is displayed via an array of pixels, controlled by voltage and the orientation of the LC molecules. LC materials are organic compounds that align themselves in the direction of an electric field and have the properties of both solid crystals and viscous liquids. There are almost 400 different types of LC compounds in use for displays. Generally, they are polycyclic aromatic hydrocarbons, or halogenated aromatic hydrocarbons. The following section describes one way in which light is transmitted or blocked from transmission in a TN-LCD. Figure 3-5 illustrates this process. Light, which in a TFT-LCD originates from the backlight source or unit, passes through a polarizer before striking the rear panel. This polarizer blocks the transmission of all but a single plane of lightwave vibration. This polarization orientation is parallel to the orientation of the LC molecules and perpendicular to the polarizer plane on the opposite 22 ------- panel. The orientation of the LC is determined by the rubbing direction of the polyimide alignment layers, to which the closest molecules appear to be anchored. The layer on one panel is rubbed at 90 degrees to the other, thereby causing the LC molecular chain to twist 90 degrees between the two panels. With no voltage applied, the twisted LC structure is fixed. Therefore, light entering from the rear and travelling through the LC cells follows the twist and arrives at the front panel in a plane parallel with this polarizer. As a result, the light is transmitted. When voltage is applied, an electric field is set up between electrodes, one on each of the two panels. The LC molecules align themselves in the direction of the electric field, thereby destroying the twist. The light travels through the cells, arriving at the front panel in a plane perpendicular to the rear polarizer, and is blocked. The field strength will determine how much of the light is blocked, thereby creating a grayscale. NCHttMT Figure 3-5: TN Field-Effect LCD Operating Principles 29 Castellano, J.A., Handbook of Display Technology, Academic Press, 1992. 23 ------- Addressing occurs when the pixels are manipulated with voltage to turn off and on, creating an image on the display screen. The active-matrix LCD uses direct addressing, which requires a switch (the TFT) and a capacitor at each pixel. The TFT is controlled by electrodes, which are the gate and source/drain regions on the transistor. The pixel is addressed by controlling current to the TFT, allowing the transistor to turn on and off. When voltage is applied, there is a short delay while LC molecules align themselves, resulting in a slightly opaque pixel. Also, the capacitor holds the charge for a short period of time after the voltage is removed and the molecules must reorient themselves to their original, 90-degree twist. These delays allow the display to scan the pixels and activate the appropriate ones for the desired image. The above description is for a black and white display—black, when light is blocked, and white when all wavelengths of incident light is transmitted. Full color results when each pixel is divided into three subpixels— red, green, and blue (RGB). Color filters, which absorb all but a range of wavelengths of the incident light, are used to create the subpixel color. By combining the subpixels, a wide range of color is possible. 3.4 TFT-LCD Manufacturing The following sections discuss TFT-LCD manufacturing and display assembly processes. This section is designed to provide an overview of these processes only. For available details on equipment and materials used, refer to the TFT-LCD process flow in Appendix D. 3.4.1 Glass fabrication Molten glass is prepared into flat substrates by the float or fusion draw process. The distinguishing difference between the technologies is the chemical type of the glass required and the degree of flatness. Soda lime glass is acceptable for some LCDs, and borosilicate for others. Whatever the glass material, strict controls are necessary during the glass fabrication process in order to obtain optical quality glass with satisfactory mechanical properties. The float method of forming glass uses a flat surface, a bed, onto which molten glass (the melt) flows. The glass floats on the source of the bed, made of molten tin, becoming flat (sides are parallel) and smooth. In the glass fusion process, the homogeneous melt is 24 ------- drawn downward into a uniform sheet of glass. The speed of the drawing process determines the glass sheet thickness. After fabrication, the glass sheets are trimmed to the desired size and prepared to withstand upcoming chemical, thermal, and physical activities and to meet high quality standards of optical glass. These activities include some, and perhaps all, of the following: beveling, chamfering, grinding, polishing, and annealing at 350-450 degrees Celsius. 3.4.2 Front panel patterning Prior to patterning the front panel, the substrate must be clean. The glass is cleaned with physical, chemical, or dry techniques. The list of cleaning methods covers all types that may occur in the LCD panel process. Not all of these cleans occur immediately after the glass manufacturing stage. Physical cleaning encompasses brush scrubbing, jet spray, ultrasonic, and megasonic methods. The chemical means include cleaning with organic solvents, a neutral detergent, process-specifics cleans according to manufacturing step (etching, stripping, etc.), and pure water cleans following chemical treatment. Dry cleaning processes use ultraviolet ozone, plasma oxide (to clean photoresist residue), non-oxide plasma, and laser energy (limited to localized needs rather than full-surface cleans). Because organic contamination and particulates are significant factors in reduced manufacturing yield, all three methods play important roles at different stages in the process. 3.4.2.1 Deposit ITO Before creating the necessary layers on the front panel, the glass is physically cleaned, typically using the ultrasonic method. Next, the transparent electrode material, indium tin oxide (ITO), is sputtered onto the substrate. This creates the front panel (common) electrode. 3.4.2.2 Pattern color filter Next, the black matrix is deposited and patterned, which creates a border around the color filter for contrast. Currently, most TFT-LCDs use a sputtered (physical vapor deposition, or PVD) chrome as the black matrix material, although the trend may be headed toward the use of black resin. The color filters are patterned onto the substrate in succession (RGB), either by spin coating the filter material or by electrodeposition. In each case, the pattern is 25 ------- transferred via the photolithographic process described in Table 3-1. Spin coating is more common than electrodeposition, and the same alternatives to the spin coater mentioned above may be adopted. If a black resin is used for the matrix, it will be applied after the color filter formation, rather than before, as is the case with chrome matrix. The color filter process results in a non-uniform substrate, thereby requiring a planarization step before moving on to the alignment layer creation. The surface is planarized with a layer of polyimide. 3.4.2.3 Deposit alignment layer The last material to be added to the front panel is the alignment layer, a polyimide that is applied by roll coating and then rubbed to the desired molecular orientation. 3.4.2.4 Inspect and test The substrate is finally inspected for visual defects and tested. 3.4.3 Rear Panel Patterning 3.4.3.1 Clean and inspect The rear glass substrate must be cleaned and inspected prior to the detailed and costly patterning processes. Typically, as with the front glass panel, this is accomplished with an ultrasonic water clean. 26 ------- Coat Photoresist, a photo-sensitive polyimide resin, is deposited on the substrate, typically using a spin coater. The spin coater dispenses the photoresist into the center of the substrate that is rotating. The centrifugal force resulting from the rotation causes the resist to spread across the substrate toward the edge. This method wastes approximately 90-95 percent of the photoresist material, as most is spun off of the substrate. Several alternative coating techniques have been, or are being, developed. Prebake After the photoresist is patterned, the substrate is baked to reduce the moisture content in the photoresist. Expose After prebaking, the substrate is ready to be patterned. This is accomplished by placing a mask with the desired pattern on top of the substrate and exposing the photoresist to light of a specific wavelength. Develop Depending on the type of photoresist used, specific areas (either those exposed, or those masked) are removed with a developing solution, leaving behind a pattern. Clean After developing the pattern, the substrate is cleaned in water to remove chemical residue and then dried. Bake The photoresist may be baked once again in order to remove moisture and harden the resist before the upcoming etch step. Etch The substrate is now etched to remove the material that was deposited onto the entire substrate and patterned. In this case, the black matrix material (chrome) not covered by photoresist is etched away, leaving a distinct, desired pattern. Depending on the materials to be removed and the linewidth requirements, a wet or dry etch is used. Wet etch involves a solvent immersion or spraying followed by a water clean. Dry etch is a plasma-based reactive ion etch. Strip/Clean/Inspect The photoresist is then completely removed from the substrate and cleaned (with water), dried, and inspected. The stripping solution is a solvent, typically either N- methyl pyrrolidinone (NMP) or trimethylamine hydrochloride (TMAH), depending on the type of photoresist. The patterning process is similar for all standard photolithograhic patterning in semiconductor and LCD manufacturing. The etchants and etching equipment used, however, will vary depending on the material being patterned. A plasma etch may be used for final resist cleaning. Table 3-1: Standard Photolithographic Patterning Process 27 ------- 3.4.3.2 Pattern TFTs The rear panel is where the transistors are created, which requires many more steps than the front panel. The transistors are made up of the regions illustrated in Figure 3-6 and discussed below. Each region requires the full photolithographic patterning process. Detailed process flow spreadsheets are provided in Appendix D. Gate The gate metal, typically aluminum, is sputtered onto the substrate and patterned. The aluminum may be dry or wet etched. Gate dielectric/channel/etch stop The gate SiNx (or SiOx) dielectric, a-Si channel, and SiNx etch stop layer are deposited in succession in a chemical vapor deposition tool. The a-Si is patterned and dry etched. Pol^mldt Alignment raxxivatinn C«nl«Ct* Cat* Insulator SemkanductfH Thin-film Figure 3-6: Etch/Stop Structure TFT TFT island A doped a-Si layer is deposited using CVD, patterned, and dry etched. Pixel electrode The pixel electrode is formed by sputtering ITO. The ITO layer is annealed (to reduce film stress) and patterned, using either wet or dry etch. 28 ------- Contact hole and source/drain metal A contact between the doped (n+) a-Si layer and the source/drain metals (deposited in the next step) is formed by patterning a hole and etching to expose the n+a-Si. Next, the source/drain metal is sputtered (metal type) and patterned, using either wet or dry etch. 3.4.3.3 Deposit passivation layer/test/inspect The surface must receive a passivation layer of SiNx for protection, after which the device is inspected and electrically tested. 3.4.3.4 Deposit alignment layer The substrate is cleaned prior to rubbing to ensure a paniculate and contaminant-free surface. Contamination is detrimental to the success of the rubbing process. The thin polymer alignment layer is deposited onto the glass surface by spin coating or printing, and then baked to remove moisture. It is then "rubbed" with fabric in the direction desired for LC orientation. The very fine grooves resulting in the layer help the LC molecules align properly. The rubbing mechanism is typically a cloth on a belt that is attached to a roller, which moves across the substrate, rubbing as it advances. The substrate is then cleaned before moving to the next step. 3.4.4 Front Panel Patterning-IPS The fabrication of the front panel for the IPS mode display is the same as that described above with one exception: no ITO electrode is formed on the front panel. 3.4.5 Rear Panel Patterning-IPS The structure described in the following section is a top-gate IPS TFT. The manufacturing advantage is the reduction in the number of mask (patterning) layers from six or seven to potentially four. In the IPS mode, the electrodes are on the same panel. Therefore, the electric field is set up between the pixel and the common (counter) electrodes on the rear panel (see Figure 3-7), rather than between the front and rear of the display (as is the case in the typical TN structure). The LC used in this mode aligns itself horizontally, unlike the vertical alignment of the TN. Light shield metal Figure 3-7 illustrates an IPS-mode TFT with a bottom-gate structure. Some IPS designs create the gate at the top of the transistor. In this case, there is a risk of exposing the a-Si 29 ------- layer to backlight energy. This exposure could generate leakage (unwanted) current. Therefore, a layer of chrome is sputtered to act as a light shield. The light shield is patterned and either wet or dry etched. Dielectric A passivation layer of SiOx may be deposited through a CVD process. It may be eliminated, as channel protection can be provided by the SiNx layer deposited as part of the island formation. Source/drain metal The source/drain metal is sputtered, patterned, and wet etched. This metal can be aluminum (Al)-based, titanium (Ti), molybdenum (Mo), chrome (Cr), tungsten (W), molybdenum/tantalum (Mo/Ta), or Mo/W. The etch process is typically dry (see process flow in Appendix D for etchant chemistry). Analyzer Black Matrix Color Filter Liquid Crystal Molecules PolyirrJde Alignment Layer Semiconductor Thin-Film Passivation (SiNx) Drain Gate Pixel Electrode (Source) Metal Counter Electrode Polarizer Figure 3-7: Hitachi IPS TFT 30 ------- Island The TFT island is created similarly to that for the E/S structure. A single-chamber CVD process is used to deposit a doped (n+) a-Si, a-Si, SiNx combination. The a-Si layer is patterned and dry etched. Gate, pixel, common electrode The gate, pixel, and common electrodes are all formed on the rear panel substrate simultaneously, and then patterned in a single mask step. The metal is commonly wet etched. As with the traditional TN-based rear panel process, following the TFT formation the substrate is coated with an alignment layer and rubbed. 3.4.6 Display cell and final module assembly At this stage of the process, the color filter substrate (top glass) and TFT substrate (rear glass) are joined with seal material, and liquid crystal (LC) material is injected into the small space in between. Polarizing films are added to the outside of each substrate and the driver electronic PWBs are attached. Finally, the backlight unit is added to complete the display module, the remainder of the electronics is attached, and the entire unit is tested. 3.4.6.1 Seal panels At this point, the color filter substrate and TFT substrate are ready to be assembled. First, an adhesive seal material is applied, usually by either silkscreening or screen printing. A hole is left in the seal for later LC material injection. After the adhesive is applied, it is cured in order to outgas solvents in the material and achieve partial cross-linking of the polymer. This makes the material less tacky (B-stage material), which allows the plates to touch during alignment. Before sealing the two substrates (accomplished by lamination), spacers are deposited on one of the substrates to maintain a precise cell gap (between 5-10 micrometers) between the two surfaces. These spacers are either glass or plastic. The substrates are then aligned and laminated by heat and pressure to complete the cross-linking of the polymer. ------- 3.4.6.2 Inject LC The LC material is injected into the gap produced by the spacer. The hole that was left open for this injection is sealed with the same type of resin and cured. 3.4.6.3 Attach polarizers The last step in the display cell assembly is the polarizer attachment. The polarizers are typically in rolls or precut sheets, and are applied to the outside of each glass panel with the help of an adhesive layer that is already on one side of the polarizer. The module is cleaned before moving on to inspection and test. 3.4.6.4 Inspect and test The display module is inspected and functionally tested. The most common display failures can be traced back to particulates and problems with the cell gap. 3.4.7 Module Assembly 3.4.7.1 Attach backlights The light source for the TFT-LCD is a backlight unit, which is usually a cold cathode fluorescent tube (CCFT). A typical desktop unit has four backlights, which are placed around the edges of the display. A light pipe projects the light across a diffuser screen to provide uniform illumination. If the IPS TFT structure is used, eight backlights are required. 3.4. 7.2 Attach electronics After the cell is inspected and the printed wiring boards (PWBs) are cleaned, the electronics are attached to complete the display module. Driver chips are attached either on the glass substrate (chip-on-glass, or COG) or near it with tape automated bonding (TAB) on flex circuit (chip-on-film, or COF). Alternatively, the chips may be mounted on PWBs (chip-on-board, COB). The use of TAB bonding for COF device attach is most common. The controller PWB is attached as are other passive components and packaging hardware. 32 ------- 3.4. 7.3 Final test and ship Once all interconnects are attached, the unit goes through a final electrical test and is shipped. 33 ------- Appendix A Flat Panel Display Technologies30 Technology Description Applicability to DfE Project Liquid Crystal Displays (LCD) A liquid crystal material, acting like a shutter, blocks, dims, or passes light unobstructed, depending on the magnitude of the electric field across the material.31 A backlight provides the light source. Included in the DfE Computer Display Project life-cycle study. Descriptions of the subtechnologies and whether or not they are included in the study are presented below. (1) Passive matrix (PMLCD) Liquid crystal (LC) material is sandwiched between two glass plates, which contain parallel sets of transparent electrical lines (electrodes) in a row and column configuration to form a matrix. Every intersection forms a pixel, and the voltage across the pixel causes the LC molecules to align and determines the shade of that pixel.32 Traditionally for low-end applications (e.g., calculators, wrist watches). Higher end applications use a super- twisted nematic (STN)33 construction. The liquid crystal material is twisted between 180 and 270 degrees, which improves the contrast between the "on" and "off' states, resulting in a clearer display than with the twisted nematic (twisted only 90 degrees.34 However, cost and performance issues limit this technology from wide application in the desktop market, therefore, it will not be evaluated in the study. (2) Active matrix (AMLCD) Similar to the PMLCD, except an electronic switch at every pixel provides faster switching and more shades. The addressing mechanism eliminates the viewing angle and brightness problems suffered by PMLCD. Requires more backlight than PMLCD due to the additional switching devices on the glass (at each pixel). Various switching types are listed below: Provides vivid color graphics in portable computer and television screens.35 This technology meets the functional unit specifications in this study. Specific subcategories are described below. 30 Socolof, M.L., et al., Environmental Life-Cycle Assessment of Desktop Computer Displays: Goal Definition and Scoping, (Draft Final), University of Tennessee Center for Clean Products and Clean Technologies, July 24, 1998. 3! Office of Technology Assessment, Flat Panel Displays in Perceptive, OTA-ITC-631, Washington, DC: U. S. Government Printing Office, September, 1995. 32 Ibid. 33 Traditional light modulating methods for LCD technologies include twisted nematic (TN), super-twisted nematic (STN), double STN, triple STN, and film-compensated STN. The STN is the current standard for high-end PMLCD applications. 34 Office of Technology Assessment, Flat Panel Displays in Perceptive, OTA-ITC-631, Washington, DC: U. S. Government Printing Office, September, 1995. 35 Ibid. 34 ------- Technology Description Applicability to DfE Project AMLCD Switch Types: (2a) Thin-film transistor (TFT): The transistor acts as a valve allowing current to flow to the pixel when a signal is applied. The transistors are made of various materials including: amorphous silicon (a: Si), polycrystalline silicon (p:Si), non- Si[CdSe].36 Two different TFT light modulating modes are twisted nematic (TN) and in-plane switching (IPS).37 In comparison to the TN mode, the IPS mode requires more backlight but fewer manufacturing steps. The current standard AMLCD switching mechanism for computer displays is a: Si TFT. Polycrystalline Si is not suitable for larger than about 5" displays. Both the TN and IPS a: Si TFT AMLCD technologies are analyzed in the DfE project. (2b) Diode matrix: The diode acts as a check valve. When closed, it allows current to flow to the pixel charging it. When opened, the pixel is disconnected and the charge is maintained until the next frame.38 The diodes are found to short easily and must be connected in series to achieve long life usability. The diode displays are also limited in size to smaller than that of the functional unit defined for the DfE study. (2c) Metal-insulator metal (MIM): The MIM is a diode type switch using metal-insulated-metal fabrication techniques.39 Temperature sensitive, which creates gray scale nonuniformities. They are also size-limited, like other diode type displays and therefore not included in the study. (3) Active-addressed LCD Hybrid of passive and active matrix. The pixels are addressed using signals sent to the column and row as determined using an algorithm encoded into an integrated circuit (1C). The 1C drives each row of pixels more or less continuously and drives multiple rows at one time.4 . 40 Employed in notebook and desktop monitors > 12.1". However, they need special drivers41 have slow response times, and their contrast worsens as panel size increases. Therefore, this technology does not meet the specifications of the functional unit and is excluded from evaluation in the DfE study. (4) Plasma-addressed liquid crystal (PALC) The pixel is addressed using row electrodes, which send the signal, and column gas channels, which conduct a current when ionized.42 PALC displays are in development to be used as large low cost displays. Production of the displays have not yet occurred and they are not included in the study. 36 Castellano, J., Handbook of Display Technology, Stanford Resources, Inc., San Jose, CA., 1992. DsiplaySearch FPD Equipment and Materials Analysis and Forecast, Austin, TX, 1998. 38 Castellano, J., Handbook of Display Technology, Stanford Resources, Inc., San Jose, CA., 1992. 39 Office of Technology Assessment, Flat Panel Displays in Perceptive, OTA-ITC-631, Washington, DC: U. S. Government Printing Office, September, 1995. 40 Ibid. 41 Ibid. 42 Ibid. 35 ------- Technology Description Applicability to DfE Project (5) Ferroelectric LCDs (FLCD or FELCD) The pixel is addressed using positive or negatives pulses to orient the crystals. The positive pulse allows light to pass (light state) and the negative pulse causes the blockage of light (dark state).43 A ferroelectric liquid crystal is bistable and holds its polarization when an electric field is applied and removed.44 They are also called surface stabilized ferroelectric (SSF) LCDs. Has high resolution with very good brightness, but limited color palette.45 Limited color palette does not meet color specification of functional unit. Plasma Display Panels (PDF) An inert gas (e.g., He, Ne, Ar) trapped between the glass plates emits light when an electric current is passed through the matrix of lines on the glass. Glow discharge occurs when ionized gas undergoes recombination. lonization of atoms occurs (electrons are removed), then electrons are recombined to release energy in the form of light. Full color plasma displays use phosphors that glow when illuminated by the gas.46 Established technology. Good for large screens (e.g., wall-mounted televisions), but are heavier and require more power than LCDs.47 Designed for large screens and are larger displays than specified for desktop applications. Therefore, not included in the study. Electrolumines- cent Displays (EL) A phosphor film between glass plates emits light when an electric field is created across the film.48 EL uses a polycrystalline phosphor (similar to LED technology, which is also an electroluminescent emitter, but uses a single crystal semi-conductor). ELs are doped (as a semiconductor) with specific impurities to provide energy states that lie slightly below those of mobile electrons and slightly above those of electrons bound to atoms. Impurity states are used to provide initial and final states in emitting transitions.49 Also referred to as thin- film EL (TFEL). Variations: AC thin- film EL (AC-TFEL), active matrix EL (AMEL), DC EL, organic EL. Lightweight and durable. Used in emergency rooms, on factory floors, and in commercial transportation vehicles.50 Problems found in the power consumption and controlling of gray levels. Targeted toward military, medical, and high-end commercial products; therefore not included in the scope of the DfE project. 43 Castellano, J., Handbook of Display Technology, Stanford Resources, Inc., San Jose, CA., 1992. 44 Peddie, Jon, High Resolution Graphics Design Systems, McGraw Hill, New York, NY, 1994. 45 Ibid. 46 Office of Technology Assessment, Flat Panel Displays in Perceptive, OTA-ITC-631, Washington, DC: U. S. Government Printing Office, September, 1995. 47 Ibid. 48 Ibid. 49 Peddie, Jon, High Resolution Graphics Design Systems, McGraw Hill, New York, NY, 1994. 50 Office of Technology Assessment, Flat Panel Displays in Perceptive, OTA-ITC-631, Washington, DC: U. S. Government Printing Office, September, 1995. 36 ------- Technology Description Applicability to DfE Project Field Emission Displays (FED) Flat CRT with hundreds of cathodes (emitters) per pixel (form of cathodeluminescent display); eliminates single scanning electron beam of the CRT. Uses a flat cold (i.e., room temperature) cathode to emit electrons. Electrons are emitted from one side of the display and energize colored phosphors on the other side.51 Not commercially available, but anticipated to fill many display needs.52 Could potentially apply in all LCD and CRT applications. High image quality as with CRT, but less bulky and less power use than with CRT. A number of roadblocks to this technology taking over the AMLCD market include proven manufacturing processes (problems found in the reliability and reproducibility of the devices), efficient low-voltage phosphors, and high voltage drivers. The technology is targeted toward military, medical and high-end commercial products and not included in the DfE study. Vacuum Fluorescent Displays (VFD) Form of cathodeluminescent display that employs a flat vacuum tube, a filament wire, a control grid structure, and a phosphor-coated anode. Can operate at low voltages, because very thin layers of highly efficient phosphors are coated directly onto each transparent anode.53 VFDs offer high brightness, wide viewing angle, multi-color capability, and mechanical reliability. Used in low information content applications (e.g., VCRs, microwaves, audio equipment, automobile instrument panels). No significant uses seen for computer displays.54 Digital Micromirror Devices (DMD) Miniature array of tiny mirrors built on a semiconductor chip. The DMD is used in a projector that shines light on the mirror array. Depending on the position of a given mirror, that pixel in the display reflects light either onto a lens that projects it onto a screen (resulting in a light pixel) or away from the lens (resulting in a dark pixel).55 Just beginning to be used mainly as projection devices, and has not been developed for use that would match the functional unit of the DfE study.56 51 Office of Technology Assessment, Flat Panel Displays in Perceptive, OTA-ITC-631, Washington, DC: U.S. Government Printing Office, September, 1995. 52 Ibid. 53 Peddie, Jon, High Resolution Graphics Design Systems, McGraw Hill, New York, NY, 1994. 54 Ibid 55 Office of Technology Assessment, Flat Panel Displays in Perceptive, OTA-ITC-631, Washington, DC: U.S. Government Printing Office, September, 1995. 56 Ibid. 37 ------- Technology Description Applicability to DfE Project Light Emitting Diodes (LED) The LED device is essentially a semiconductor diode, emitting light when a forward bias voltage is applied to a p-n junction. The light intensity is proportional to the bias current and the color dependent on the material used. The p-n junction is formed in a III-V group material, such as aluminum, gallium, indium, phosphorous, antimony, or arsenic. For low information display applications, which makes it not capable of meeting the requirements of the functional unit of the study. Color, power, and cost limitations prevent the emergence into the high information display market.57 Elect rochromic Display Open-circuit memory using liquid electrolytes.58 Non-emitter (as LCDs), as opposed to emitters (e.g., EL, FED, PDF). Outstanding contrast and normal and wide viewing angles, open-circuit memory. Complex and costly, involving liquid electrolytes, poor resolution, poor cycle life, lack of multicolor capability, etc. Not suitable for computer displays in past; however, new technology may be promising.59 Light Emitting Polymers Developing technology (Holton 1997).60 Developing technology. 57 Castellano, J., Handbook of Display Technology, Stanford Resources, Inc., San Jose, CA., 1992. 58 Peddie, Jon, High Resolution Graphics Design Systems, McGraw Hill, New York, NY, 1994. 59 Ibid. 60 Holton, W.C., "Light-emitting polymers: increasing promise," Solid State Technology, vol. 40, no.. 5, p. 163, May 1997. 38 ------- Appendix B CRT Manufacture Process step Fabricate glass Mix batch Melt Fine Condition Form panel Anneal Finish Clean Cut Grind and polish Inspect Test Pattern panel glass Clean Bitch" Apply (contrast) grille material Dry aquadag Apply green phosphor slurry Dry phosphor Expose green phosphor Develop Dry Apply blue phosphor slurry Expose blue phosphor Develop Dry Apply red phosphor slurry Expose red phosphor Develop Dry Apply lacquer leveling film Apply reflective layer Equipment spin coat spin coat IR lamp near-UV lamps spin coat near-UV lamps spin coat near-UV lamps spin coat or spray evaporate Process Material/Chemical acid aquadag (polyvinyl alcohol} slurry mixture: water, wetting agents, polyvinyl alcohol water ZnS'Ag water Y-,O;,S:Cu water polymer aluminum Notes 1 1000 angstroms 39 ------- Process step Prepare funnel Coat inside of funnel (dag) Dry coating Apply frit Harden Manufacture shadow mask Etch hole pattern Clean Anneal Draw to face plate contour Blacken mask and side pieces Weld side pieces Anneal magnetic shield Blacken shield Manufacture electron gun Hydrogen fire metals Fixture metal parts Heat glass pillars Press pillars over tabs on electrode Mount to glass stem Join stem to neck insert cathodes into support pins Insert heater Manufacture electron gun Weld assembly to support pins Weld ribbon conductors Weld centering springs, getter Add additional parts Assemble mask to panel Coat shadow mask back side Curve shadow mask Weld springs (brackets) to frame Weld mask Position shield on brackets Equipment sponge, flow coat, or spray evap oven evap oven oven oven melt hydraulic press Process Material/Chemical aquadag Pb glass frit (P'bO, ZnO, BO), nitrocelluose binder, amyl acetate remove amyl acetate rolled iron or Invar metal etchant: ferric chloride solution water aluminum-killed steel bismuth oxide Notes 2 3 4 5 40 ------- Process step Join bulb and gun Attach panel to funnel Cure frit Seal gun to bulb Exhaust/finish assembly Cut excess neck glass Evacuate Heat tube Notes: Equipment clips vacuum exhaust Process 1 Notes Material/Chemical } total layer <.002 inch > 440 °C fuse base ito funnel neck 6 350 °C (1) Electrically conductive carbon materials (graphite) w/silicate binders in water suspension. (2) Aquadag with addition of electrical conductivity modifiers, higher concentration of silicate binder, and possibly iron. (3) 300/400 series steels (contain Fe, Ni, Cr); borosilicate glass insulation; Ni cathode; mix. of Ba, Sr, Ca carbonates emitter material; W wire heater coated with Al oxide. (4) Glass pillars heated to softening temperatures. (5) Arcing wires, magnet pole pieces, magnetic shunts. (6) Excess neck glass is reused by glass companies. 41 ------- Appendix C NEC CRT: Detailed Bill of Materials NEC JC-1549VNA Sub No. Entry No. Name Qty. 1 Material 1 Weight 1 1 (grams) Total (grams) Bill of Materials for: NEC JC-1549VNA 1.1 1.2 1-S .3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 chassis right hand shield left hand shield top shield insulator pad back shield shield brackets screws swivel base large rubber feet brackets swivel base small base shield base bracket shadow mask anode connection anode cap anode cap insert flass racket 1 bracket 2 bracket 4 xy control 1 xy control 2 Bill of Materials for: Neck assembly 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13 2.14 base neck top neck neck ring large 1 neck ring small 1 neck ring small 2 meek ring large 2 ferrite magnet Cu attached to magnet Cu attached to neck extraneous copper insulating rings brass ring rubber gaskets screw with washers 1 IPS 1 1 steel 1 I steel 1 1 steel 1 j polyester 1 1 steel 4 jbrass 46 izinc plated steel 1 IPS 4 Isilicone rubber 4 jbrass 1 IPS 1 j steel 2 IPS 1 1 steel 1 1 steel 1 j rubber 1 1 steel 1 j glass 1 1 steel 1 1 steel 1 1 steel 1 JPC 1 IPC 1 IPS 1 IPS 1 IPS 1 IPS 1 IPS 1 IP'S i i 1 1 copper 1 i copper 1 1 copper 4 Ipolysulphone 1 1 brass 2 1 rubber 4 Izinc plated steel 1624.9 499.2 417.4 64.5 27.2 190.5 4 1.6 272.2 6.5 1 169.9 1079.5 46.4 626 3.3 16.4 3.6 5511.1 46.4 90.7 246.7 9.4 6.2 66.9 15. 9 15 4.5 4 14.5 295.6 134.5 108.9 6.4 4.1 2.1 6 2.9 1624.9 499.2 417.4 64.5 27.2 190.5 16 73.6 272.2 2 4 169.9 1079.5 92.8 626 3.3 16.4 3.6 5511.1 46.4 90.7 246.7 9.4 6.2 66.9 i'5.9 15 4.5 4 14.5 295.6 134.5 108.9 6.4 16.4 2.1 12 11.6 42 ------- Sub No. Entry No. Name 2.15 i neck clamp 2.16 1 brackets Bill of Materials for: Gun 3.1 {gun 3.2 {'brackets 3.3 i attachment to glass 3.4 1 attachment to b oard 1 3.5 j attachment to b oard 2 3.6 3.7 connectors screws 3.8 j shield 3.9 JPWB board 194 mm x 122 jmm 3.9a 1 heat sink 3.9b 3.9c SOP resistors 3.9d j capacitors 3.9e 3.9f transistors resistors 3.9g I variable resistors 3.9h j jumpers 3.9i connector 12 pin 3 . 9j j connector 6 pin 3 . 9k" j connector 2 pin Bill of Materials for: Power board 4. 1 jflyback transformer 4.1a wire 4 . 1 b j connector 2 pin 4.1c 4.1d wire wire 4.1e I magnet 4. If j steel pin 4.1g Irubber cap 4.1h misc. potting material 4.1i jcopper wire 4.2 JPWB additional 194mm x J95 mm 4.2a {capacitors 4.2b 4.2c 4.2d SOP transistors resistors 4.2e {jumpers 4.2f 4.2g wire connectors 5 pin 4.3 JPWB (x controller) 4.3a j'PWB Qty. 1 Material 1 Weight 1 1 (grams) 1 j steel 4 {brass 1 j steel 2 {PC 1 jplastic 1 {polycarbonate 1 {polycarbonate 2 {aluminum 4 jzinc plated steel 1 j steel 1 14 layer 4 {aluminum 1 : 117 I 60 | 27 t 4 J7W 9 { 7 j 1 { 1 | 2 j i i 1 {446 mm 1 i 2 {172mm 1 {194 mm 1 jferrite magnet 1 j steel 1 {rubber 1 j silicone 1 jcopper 1 14 layer 47 t 9 j 12 I 149 | 6 t 5 J156 mm 2 { {2 layer 1 {114x20 mm 4.4 1.2 19.4 2.9 2.9 4.2 10.9 6.4 0.9 79.4 17.6 320.8 161.6 3.8 1 176.2 38.2 Total (grams) 4.4 4.8 19.4 5.8 2.9 4.2 10.9 6.8 3.6 79.4 70.4 161.6 3.8 1 176.2 38.2 43 ------- Sub No. Entry No. Name 4.3b jinductor 4.3c 4.3d wire 3 pin connector 4.4 JPWB (y controller) 4.4a IPWB 4.4b wire 4.4c 13 pin connector 4.4d resistor 4.5 1 knobs sm 4.6 jknobs Ig 4.7 j aluminum shielding 4.8 jheat sink 1 4.9 1 heat sink 2 4.10 jheat sink 3 4.11 ledge bracket 4.12 4.13 wire connector 12 pin 4.14 JPWB power, 349.5 x 245 jmm 4.14a Ifuse 4.14b j variable resistors 4.14c resistors 4.14d I capacitors 4.14e transistors 4.14f JSOP 4.14g jdiod'e 4.14h jjunpers 4.141 1 inductor j insulating tape 4.14J jinductor 4.14k copper tape 4.141 jinductor insulating tape 4.14m 1 inductor j insulating tape 4.14n 1 inductor Qty. 1 Material 1 Weight 1 1 (grams) 1 j copper i Ibaciite 2 j 156 mm i t 12 layer 1 135 x 74 mm 2 j 156 mm i i 1 j 5 IPS 2 JPS 1 j aluminum 1 j aluminum 1 1 aluminum 1 j aluminum i 1 steel 12 J32mm 2 1 1 |4 layer i i 1 j 251 1 165 j 28 1 8 j i t 25 j i Ibaciite 1 I copper 1 Irerrite 1 j polyester i Ibaciite 1 j copper 1 Irerrite 1 I copper i jbaciite 1 j copper 1 Irerrite 1 j polyester i Ibaciite 1 I copper 1 Irerrite 1 j polyester i Ibaciite 1 j copper 1 Irerrite 5.4 4.6 2.8 4.4 ' I36".T" 20.7 38.9 15.2 87.2 6.8 9.6 7.6 0.6 8.7 26.8 139.5 2.4 9.5 12 8.5 4.8 5.7 7.2 5.1 0.5 3.8 4.8 3.4 Total (grams) 5.4 4.6 14 8.8 136T" 20.7 38.9 15.2 87.2 6.8 9.6 7.6 0.6 8.7 26.8 139.5 2.4 9.5 12 8.5 4.8 5.7 7.2 5.1 0.5 3.8 4.8 3.4 44 ------- Sub No. Entry No. 4.14o Name insulating tape inductor 4.14p inductor 4.14q 4.14r 4.14s 4. Hit 4.14u 4.14v 4.14w connector 15 pin connector 3 pin connector 5 pin connector 6 pin connector 2 pin connector 4 pin wire 4.15 1 power switch 4.16 j power cord receptacl e 4.17 j power cord Bill of Materials for: PWB attached to power 5.1 5.2 5.3 5.4 5.5 5.6 PWB, 82 x 30 mm SOP' resistors capacitors transistors connector 5 pin Bill of Materials for: PWB attached to power 6.1 6.2 6.3 6.4 6.5 6.6 PWB, 53 x 52 mm SOP resistors capacitors transistors connector l3 pin 6.7 j jumpers Bill of Materials for: PWB attached to power 7.1 7.2 7.3 7.4 7.5 7.6 PWB, 44 x 96 mm SOP resistors capacitors transistors connector 1 1 pin 7.7 j jumpers Qty. 1 Material 1 Weight 1 1 (grams) 1 2 2 O 2 2 o 4 i r\ i 4 i i i board by 1 1 r\ 4 1 i board by 1 i 24 10 6 1 4 board by r\ 37 11 5 1 2 polyester fertile magnet copper baclite copper ferrite 296mm 'PS ABS 475 mm length cable connector 4 layer solder connecto 2 layer solder connecto '2 layer 0.4 17.9 1.8 5.4 4.6 4.2 5.2 34 292.7 r r Weight Total Total (grams) 0.4 35.8 3.6 16.8 9.2 8.4 5.2 34 292.7 11636.8 45 ------- Appendix D TFT-LCD Manufacture Glass Panel Process Step 1 Equipment Fusion Method Material/Chemical 1 Notes barium borosilicate, e.g., Corning 7059: aluminoborosilicate; 49% SiO2, 10% 0.7mm thick AL^; 15% B2O3; 25%BaO; 1% other Mix 1 Melt glass Fine Condition Flow glass Draw glass Cut glass ^band, wire, or circular blades Bevel/chamfer/heat glass Grind (may be eliminated) Polish (may be eliminated) Chemical finishing Clean (physical) or Clean (chemical) or Clean (dry) Anneal (back panel onl Float method Mix Melt Fine Flow glass Cool glass Cut glass sand, garnet, corundem, silicon, carbide, boron carbide, or diamond potassium nitrate brush, scrub, ultrasonic, or megasonic organic solvent; neutral detergent; or chemical clean; and water ultraviolet ozone; plasma oxide; plasma non oxide; or laser y) barium borosilicate or aluminoborosilicate; 0.7mm thick molten tin bed float on bed of molten t controlled atmosphere still on molten tin Bevel/chamfer/heat glass Grind (may be eliminated) Polish (may be eliminated) Chemical finishing potassium nitrate Clean (physical) *b"rush, scrub, ultrasonic, or megasonic or Clean (chemical) 350-400°C e.g., Corning 7059: 49% SiO2, 10% AL^; 15%B2O3; 25%BaO; 1% other in in chemically organic solvent; neutral detergent; or chemical clean; and water or Clean (dry) ^ultraviolet ozone; plasma oxide; plasma non oxide; or laser Anneal (back panel only) 46 ------- Front Panel Pattern-TN Process Step 1 Equipment Process 1 Ancillary Material 1 Material Notes Clean glass j Ultrasonic clean/spin rinse dryer JIPA, water, nitrogen Deposit ITO JPVD Coat photoresist j Spin coater Bake jOven Expose I Stepper Develop | Developer Clean I Spin rinse dryer Bake photoresist jOven Etch ITO j Plasma etcher Strip photoresist IDeveloper Clean I Spin rinse dryer Deposit black j Sputter matrix material j Coat photoresist I Spin coater Bake jOven Expose j Stepper Develop j Developer Clean I Spin rinse dryer Bake I Oven EtchCr 1 Wet bench Strip photoresist j Wet bench Clean jSpin rinse dryer Inspect j Apply (R) color I Extrude/spin or filter material ; slit/spin coater Bake jOven Expose I Stepper Develop j Developer Clean jSpin rinse dryer Apply (G) color j Spin coater filter material j Bake lOven Expose j Stepper Develop IDeveloper Clean j Spin rinse dryer Apply (B) color 1 Spin coater filter material j Expose I Stepper Develop IDeveloper Clean I Spin rinse dryer Planarize jCoat I Indium tin oxide 1 Polyimide ITMAH 1 Water iClj; HBr; He; O-, ITMAH 1 Water Chrome j 1 Polyimide ITMAH 1 Water ITMAH 1 Water 6.8-2.6 um acryl 1 Same as process epoxy resin, Sbq-; material PVA j ITMAH 1 Water Wet etch: HCL Alternative: black resin & photo process Pigment- dispersion method, 99% TFTs Negative resist- extra strip not required Pigment-diffused j Same as process material acryl epoxy resin I ITMAH 1 Water Pigment-diffused 1 Same as process material acryl epoxy resin j ITMAH 1 Water Polyimide 1 47 ------- Process Step Deposit alignment layer Bake Rub Inspect Test Equipment Roll coat Oven Rubbing machine Microscope Process 1 Material | Polyvinyl alcohol; p acid solution Ancillary Material olyesters; poly- s Notes iloxanes; polyamic 48 ------- Rear Panel Pattern-TN Process Step 1 Equipment Clean bottom I Ultrasonic or glass jbrush inspect 1 Deposit gate metal; PVD Coat photoresist I Spin coater Bake I Oven Expose 1 Stepper Develop I Developer Clean jSpin rinse dryer Bake photoresist JOven Etch gate metal I Plasma etcher Strip photoresist IDeveloper Clean 1 Spin rinse dryer Inspect j Deposit dielectric jPECVD material 1 Deposit channel jPECVD material I Deposit etch stop jPECVD layer j Coat photoresist j Spin coater Bake lOven Expose j Stepper Develop IDeveloper Clean ISRD Bake photoresist lOven Etch SiNx j Plasma etcher Etch a-Si I Plasma etcher Etch SiNx j Plasma etcher Strip photoresist IDeveloper Clean ISRD Deposit ohmic jPECVD contact material 1 Coat photoresist j Spin coater Bake I Oven Expose i Stepper Product 1 Ancillary Materials | Materials Notes IIP A, nitrogen, 1 alkali-free likely ! water I future material One of the following: jTi/Al/Ti possible Al, Al + barrier, Al + metal, Al alloy jfuture metal jlayers jPolyimide 190- 95% wasted ; ; on traditional ; ; spin coater INMP 1 1 Water 1 j lor wet etch + ; ; clean |A1: Cl2+BCla/Cl2 lAl+barrier: CL; BCl; N7; CF4 lAl+metal: C12; BCl^; N2; CF4 1 Al alloy (Zr, Cu, Nd, Y): C12; B"C13; |N2; CF, INMP I Water SiO2 or SiN j a-Si I SiNx j iPolyimide INMP I Water |CHF3; CF4 ICF4; O2 jCF4;02orCl, INMP I Water Doped Si (n-type: As,P) iPolyimide 49 ------- Process Step 1 Equipment Develop I Developer Clean ISRD Bake photoresist jOven Etch doped a-Si jPlasma etcher Strip photoresist jDeveloper Clean I Spin rinse dryer Deposit ITO JPVD Anneal lOven Coat photoresist j Spin coater Bake lOven Expose i Stepper Develop ; Developer Clean ISRD Bake photoresist jOven Etch ITO j Plasma etcher Strip photoresist jDeveloper Clean ISRD Coat photoresist j Spin coater Bake JOven Expose I Stepper Develop j Developer Clean ISRD Bake photoresist jOven Etch n+ a- Si j Plasma etcher (contact) j Deposit JPVD source/drain metal; Coat photoresist 1 Coater Bake I Oven Expose I Oven Develop j Stepper Clean jDeveloper Bake photoresist ISpin rinse dryer Etch metal I Plasma etcher Strip photoresist iDeveloper Clean ISRD Deposit jPECVD passivation layer ; Coat photoresist | Coater Bake lOven Expose j Oven Product 1 Ancillary Materials | Materials INMP 1 Water |Ci2orCF4+O2or JNMP ; Water Indium oxide/tin oxide jPolyimide ;NMP j Water |Cl2+HBr;He; 10-,; CH4+H2 INMP j Water jPolyimide INMP 1 Water |ci2 One of the following: Al, Al + barrier, Al + metal, Al alloy Ti, Mo, Cr, W, MoTa, or MoW jPolyimide ;NMP j Water lAletch: |C12+BC13/C12 Notes SFa+HCL or wet etch + clean or wet etch + clean jAl+barrier: C12; BC13; N2; CF4 lAi'+metai': Cl2; B'Ci^; N2; CF4 1 Al alloy (Zr, Cu, Nd, Y): C12; BC13; iN2; CF4 jNMP j Water SiNx ICF4+O2 jPolyimide 50 ------- Process Step 1 Equipment Develop I Proximity printer Clean jDeveloper Bake photoresist JSRD Etch SiNx 1 Plasma etcher Strip photoresist j Clean iSRD Deposit alignment I Roll coater material j Bake lOven Rub j Rubbing machine Electrostatic discharge Test JSRD Product 1 Ancillary Materials | Materials INMP IWater JO,, N2, He, SiF,, JNMP ! Water Polyimide, 500 to 1000 A Water Notes CHFa (mixture) 51 ------- Front Panel Pattern-IP S Process Step j Equipment Clean glass 1 Ultrasonic clean/S Deposit black j Sputter matrix material j Coat photoresist I Spin coater Bake jOven Expose 1 Stepper Develop | Developer Clean 1 Spin rinse dryer Bake jOven Bitch Cr I Wet bench Strip photoresist j Wet bench Clean I Spin rinse dryer Inspect j Apply (R) color I Extrude/spin or filter material j slit/spin coater Bake jOven Expose I Stepper Develop j Developer Clean 1 Spin rinse dryer Apply (G) color j Spin coater filter material | Bake lOven Expose j Stepper Develop j Developer Clean j Spin rinse dryer Apply (B) color I Spin coater filter material ; Expose j Stepper Develop I Developer Clean jSRD Deposit alignment; Roll coat layer j Bake lOven Rub j Rubbing machine inspect 1 Microscope Test j Process Material RD Chrome 6.8-2.0 urn acryl epoxy resin, Sbq- PVA Pigment-diffused acryl epoxy resin Pigment-diffused acryl epoxy resin Poiyvinyl alcohol; siloxanes; polyarm Ancillary Material IP A, water, nitrog Poiyimide TMAH Water TMAH Water Same as process material TMAH Water Notes en Alternative: black resin & photo process Pigment- dispersion method, 99% TFTs Negative resist- extra strip not required Same as process material 'TMAH Water Same as process material TMAH Water polyesters; poly- c acid solution 52 ------- Rear Panel Pattern-IP S Process Step Clean substrate Inspect Deposit light shield metal Coat photoresist Bake Expose Develop Clean Bake Etch Cr Strip Clean Inspect Deposit dielectric Deposit source/drain metal Coat photoresist Bake Expose Develop Clean Bake 1 Equipment Product Materials (Ancillary Materials IBrush, disk, US, or MS JPVD ICoater I Oven I Stepper j Developer I Spin rinse dryer I Oven 1 Plasma etcher jPlasma asher 1 Spin rinse dryer JAOI t'C'VD JPVD ICoater j Oven j Stepper I Developer 1 Spin rinse dryer I Oven Etch" j Strip Clean Create island 1 Coat photoresist Expose Develop Clean Bake Etch island Strip Clean JPVD 1 Plasma etcher Inspect i Cr CL,;Oj C12;O2 (or wet bench) SiOj One of the following: Al, Al + barrier, Al + metal, or Al alloy SiNx, a-Si, n+ a-Si n+ a- si Positive photoresist NMP Water NMP Water Al etch: Cl-.+BCyCl., Al+barrier: C12; BC13; N2; CF4 'Al+metal: C12; B"C13; N2; CF4 Al alloy (Zr, Cu, Nd, Y):C12;BCL,;N2;CF4 NMP Water *CF4; Qj; Cl., 53 ------- Process Step 1 Equipment Deposit gate electrode 1 CVD Deposit pixel electrode; CVD Deposit common jCVD electrode j Coat photoresist ICoater Bake lOven Expose j Stepper Develop I Developer Clean j Spin rinse dryer Bake iOven Etch metal(s) j Wet bench Clean j Spin rinse dryer Strip j Developer Clean j Spin rinse dryer Deposit alignment jRoll coater layer j Bake IOven Rub j Rubbing machine Electrostatic discharge I Spin rinse dryer Test | Product Materials (Ancillary Materials Al, Al+barrier, Al+metal, or Al alloy Al, Al+barrier, Al+metal, or Al alloy Mo, Ta, MoTa, MoW, Al/Cr, or Ti/Al/Ti j Al etch: iCl2+BCl3/Cl2 lAl+barrier: C12; BCT3; |N,; CF4 i Al+metal: C12; BC13; |N2; CF4 1 Al alloy (Zr, Cu, Nd, |Y):Cl2;BCla;N2;CF4 ITi: CLj; CF4 tivio: Cl2; O2; SF§ ICr: Cl_j; O2 IW: C\; 0,; SFg IMoTa: C12; O2; SF£ Polyimide, 500 to 1000 A Water 54 ------- Display Cell Assembly Process Step Equipment Process Notes I material/chemical | Apply seal I Screen printer jEpoxy resin, acrylic resin, etc. Cure :Qye.n : 1 Apply, ^pacers l?p.ac.e.r $.P.r.a.y.e.r (p)ymyib£nze.n?~typ.e. r??.m 9r ?!^c.a. Inspection lE§i?.r£sc..°.Pe. I 1 Align and assemble plates ; tEach glass plate 1. i ; ; mm thick Cure J9y.e.n ! 1 Scribe and break * j f 400 different types j j exist; more than one j lused Inject liquid crystal Vacuum/injection j Poly cyclic j6.8 mg/cm2 system jaromatic/halogenated j j hydrocarbon; j jcyanobiphenyl; j jphenylcyclohexane j j compound j Seal " jEpoxy resin, acrylic j Sealing LC-injection I resin, etc. inpje Cure ^Uy light source/oven j } Clean Attach front polarizer Laminator jPolyvinyl alcohol- j.2 - .3 mm cellulose jiodine jtriacetate; cellulose j j acetate butyrate- I ^Pr^?£tiye. laye.r Attach rear polarizer "Laminator jPolyvinyl alcohol- j.2 - .3 mm cellulose jiodine jtriacetate; cellulose j j acetate butyrate- j j protective layer Clean inspect/test display 55 ------- Display Module Assembly Process Step Attach row drivers Attach column drivers Attach backlight Inspect i Process material/chemical j JPWB, TAB (polyimide film, sealing resin) 1 TAB (polyimide film, sealing resin) 1 Notes I Glass fluorescent material, 20ppm Hg (notebook computer) Clean circuit boards I I Test Attach controller Attach passive components Attach packaging hardware Attach interconnects Test unit j TAB (polyimide film, sealing resin) j 56 ------- Appendix E Cannon FPD: Detailed Bill of Materials Cannon FLCD 15C01 57 ------- Appendix E Cannon FPD - Detailed BOM Sub No. Entry No. Name Bill of Materials for: Canon FLCD 15CD01 1.1 1.2 1.4 1.5 1.7 1.9 1.10 1.11 1.14 1.15 1.16 1.17 1.19 1.20 1.21 1.22 1.23 1.24 1.26 1.27 1.30 1.31 1.32 1.33 1.34 Front bezel LED light pipe Adjustment PWB scr M3, 4 pnh Knob Power supply PWB Power switch bezel scr M3, 4 pnh LCD subassy Backlight assy scr M3, 4 pnh scr M3, 4 pnh Cable clamp Power supply cover scr M3, 10 pnh insulator Hitachi PWB scr M3, 4pnh NFX controller scr M3, 4 pnh Rear cover assy scr M3, 10 pnh Power supply assy scr M3, 10 pnh Base/stand Bill of Materials for: LCD subassy 1.14 4.1 4.2 4.3 4.4 4.6 4.7 4.8 4.9 4.10 4.12 4.13 4.14 Plastic frame Gasket Brightness enhancer scr M3, 4 pnh Large gasket Small gasket LCD panel assy Metal clip scr M3, 4 pnh Cable assy Hold-down clip scr M3, 4 pnh Qty. 1 1 1 3 2 1 1 7 1 1 2 18 1 1 2 1 1 6 1 6 1 9 1 4 1 1 1 1 6 1 1 1 4 1 1 1 1 Material ABS polycarb see subassy BOM ABS see subassy BOM ABS see subassy BOM see subassy BOM nylon steel polyester see subassy BOM see subassy BOM see subassy BOM see subassy BOM see subassy BOM PC-GF30 silicone rubber polyester silicone rubber silicone rubber see subassy BOM BeCu see cable assy summary BeCu Weight (grams) 150 <1 1.7 4.2 <1 25 10 150 n/a 10 n/a n/a 1 1 Formation Process inj. mold inj. mold inj. mold inj. mold inj. mold progressive die stamp die cut inj. mold dispensed extruded, die cut dispensed dispensed stamped stamped Features 3 1 brass inserts 6 brass inserts Supplier Japan Synthetic Rubber Company 3M Finish (top) screened logo as molded as molded as molded electro-galvanized microembossed Ni plate Ni plate Finish (bottom) conductive paint 58 ------- Appendix E Cannon FPD - Detailed BOM Sub No. Entry No. Name Bill of Materials for: Backlight assy 1.15 5.1 5.2 5.4 5.5 5.6 5.8 5.9 5.10 5.11 5.12 5.13 5.14 5.16 5.17 5.19 Metal plate Brass thd'd standoff scr M3, 4 pnh Foam gasket Nylon strain relief Clear protector Opaque diffuser Light pipe Corner tape White reflector Light assy scr M3, 4 pnh Nylon clamp scr M3, 4 pnh Rear plate assy Bill of Materials for: Light assy 5.13 5.13b 5.13c 5.13d Cold cathode tube Shock cushion Cable assy Bill of Materials for: Rear plate assy 5.19 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 Rear plate Cable clamp Plastic tube scr M3, 10 pnh Flat cable toroid Hold-down plate scr M3, 4 pnh Caution label Bill of Materials for: Rear cover assy 1.30 9.1 9.2 9.4 9.5 9.7 Rear cover BeCu fingers Cloth mesh Metal plate scr M3, 4 pnh Qty. 1 4 4 4 1 1 1 1 4 1 4 4 6 6 1 1 2 2 1 3 2 2 6 2 4 1 1 6 2 1 4 Material steel brass foam rubber nylon plexiglass polyester polycarbonate aluminized mylar polyester see subassy BOM nylon see subassy BOM glass, phosphor silicone rubber insulated Cu wire steel nylon polycarb hi-mu ferric steel paper ABS BeCu polyester steel Weight (grams) 175 2 <1 <1 75 10 550 «1 15 1 8.7 1.7 4.4 350 1.1 4.1 12 20.6 «1 325 1 <1 200 Formation Process progressive die stamp screw machine adhesive backed foam tape inj. mold inj. mold extruded, die cut inj. mold extrude/roll form/ e-less plate extruded, die cut inj. mold complex inj. mold complex progressive die stamp inj mold extrude/screw mach. molded progressive die stamp inj mold die stamped woven stamped Features inj. molded connector 2 piece 18 spot welds heat staked to rear cover glued to rear cover 2 pressed in screw machine nuts Supplier 3M 3M 3M Tokin Japan Synthetic Rubber Company Finish (top) electro-galvanized adhesive etched both sides Finish (bottom) microembossed both sides electro-galvanized electro-galvanized screen print ink as molded Ni plate electro-galvanized adhesive conductive paint 59 ------- Appendix E Cannon FPD - Detailed BOM Sub No. Entry No. 9.8 9.10 9.11 Name Shoulder screw Insulator scr M3, 5 type B Bill of Materials for: Power supply assy 1.32 10.1 10.2 10.3 10.4 10.5 10.6 10.7 10.8 Housing [nsulator Power supply PWB assy Pwr switch Pwr cord recept. scr M3, 4 pnh Heat sink scr M3, 4 pnh Bill of Materials for: Base/Stand assy 1.34 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 11.10 11.12 11.13 11.14 11.15 11.16 11.17 11.18 11.19 11.20 11.21 11.22 11.23 11.24 Upright Bracket 1 Bracket 2 Bracket 3 Bracket 4 Bracket 6 Axle Spring Bushing Swivel bearing 1 Swivel bearing 2 Bracket 7 Base weight Rubber feet Cover 1 Cover 2 Cover 3 Cover 4 Cover 5 Cover 6 C-clip Lg washers Sm washers Qty. 2 1 4 1 1 1 1 1 4 1 8 1 1 1 1 1 2 2 2 2 1 1 1 1 5 1 1 1 1 1 1 4 2 2 Material polyester steel polyester see subassy BOM ABS/Cu ABS/Cu aluminum UP-GF14 steel steel steel steel steel steel steel nylon stainless POM steel steel silicone rubber ABS ABS ABS ABS ABS ABS steel steel steel Weight (grams) 20 150 24 5.2 34 60 450 44 52 65 175 10 15 8 3 68 31 460 450 <1 33 27 30 35 20 95 <1 3.6 <1 Formation Process die cut progressive die stamped die cut inj. mold complex, inj. mold inj. mold stamped stamped stamped stamped stamped screw machine inj. mold stamped inj. mold stamped stamped die cut inj. mold inj. mold inj. mold inj. mold inj. mold inj. mold stamped stamped stamped Features 2 piece, 2 spot welds 3 wire pigtail w/ ferrite choke 2 piece, 22 spot welds Supplier Matsushita Finish (top) electro-galvanized electro-galvanized electro-galvanized electro-galvanized none textured paint adhesive Finish (bottom) 60 ------- Appendix E Cannon FPD - Detailed BOM Sub No. Entry No. Name Qty. Bill of Materials for: LCD panel Assembly 4.8 12.1 12.2 12.3 12.4 12.5 12.6 AMLCD cell Row driver TAB Column driver TAB Row driver input PWB Column driver input PWB Connection flex Bill of Material Summary for Cables 1 3 10 1 1 1 Material glass, misc thin films 1C chip on polyimide tape 1C chip on polyimide tape see subassy BOM see subassy BOM Cu thin film on polyimide base weight sub-total Weight (grams) 475 1 1 5 5136.6 Formation Process complex complex complex complex Features Supplier Finish (top) 2mm X 12 mm 1C, 30mm X 15mm tape 1.5mm X 10mm 1C, 20mm X 12mm tape 35mm X 12cm 21 individual wires, AWG 36, totaling 352 inches; 9 connectors with average of 5 connections each and 1.5 g weight each Bill of Materials for: NFX Controller 1.26 PWB: Board Area in Sq Inches: Components Part Number CG21503... Japan AD7224KR-1 TD62595AFT9424K J47AD 74 ACTQ244... National P39AK DS26C32ATM MC33174D XAG448... Motorola SM128 LM324M P41ADDS26C31TM AH6-0054-01N335E3B 403 592C SCC 357 Trace VialD Thick. 38.156 Qty 1 1 1 6 5 2 1 1 1 1 2 4 4 1 1 3 16 0.008 0.012 0.062 Space ViaOD #Layers (total both sides) #IO 208 20 18 20 16 14 14 16 100 100 3 3 4 4 4 6 3 0.008 0.024 4 Pitch Material Weight All Dimensions in Inches Type Pkg QFP SOP SOP SOP SOP SOP SOP SOP QFP I.C. Socket SOT-23 SOT-23 SOT SOT SOT SOT SOT-23 Lead Pitch 0.02 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.025 0.025 0.2 0.1 0.06 0.1 0.1 0.025 0.075 Length 0.375 0.095 0.08 0.065 0.075 0.1 0.065 0.075 0.215 0.016 FR4 120 Width 0.35 0.085 0.075 0.06 0.055 0.065 0.055 0.055 0.175 Finish (bottom) 61 ------- Appendix E Cannon FPD - Detailed BOM Sub No. Entry No. For SOT on line #19 20.000 MHz 20.000 MHz Socket type w/large metal bracket Ni-Zero-Insert-Flex Ni-Post Ni-Post Ni-Post Ni-Post Name 1 12 10 2 1 1 8 456 27 232 1 10 1 1 1 1 Bill of Materials for: Hitachi PWB 1.23 PWB: Board Area in Sq Inches: Components Part Number 5B2 HA17339 51CTOOTTL1451A4Y Wire Type Wire Type Wire Type Wire Type Wire Type Wire Type Can Type Can Type Can Type Trace VialD Thick. 39.781 Qty 1 1 2 8 8 8 10 2 7 4 8 8 14 2 4 4 5 Qty. 0 2 2 3 4 2 2 2 2 2 25 12 10 3 4 8 0.01 0.012 0.062 Material Al heatsink Plate Electro Cap Electro Cap Fuse Crystal Crystal Diode 1206 chip cap misc. Discrete 0805 chip resistor Connector Connector Connector Connector Connector Connector Space ViaOD #Layers (total both sides) #IO 14 16 3 3 2 2 2 2 2 6 4 9 2 2 2 2 2 Weight (grams) 0.05 0.025 0.07 0.07 0.07 0.07 0.01 0.035 4 Formation Process Pitch Material Weight All Dimensions in Inches Type Pkg SOP SOP SOT-23 SOT-23 Capacitor Capacitor Capacitor Capacitor Capacitor Transformer Choke Transformer Resistor Resistor Capacitor Capacitor Capacitor Pitch 0.1 0.1 0.1 0.1 Length 0.095 0.075 Features 0.02 FR4 205 Width 0.065 0.065 Supplier Finish (top) Finish (bottom) 62 ------- Appendix E Cannon FPD - Detailed BOM Sub No. Entry No. Can Type Open case Open case Closed case Closed case Name 1 1 1 1 1 1 4 4 4 26 2 14 19 75 Bill of Materials for: Adjustment PWB 1.4 PWB: Board Area in Sq Inches: Components Part Number Trace VialD Thick. 9.2 Qty 3 1 1 1 1 1 Bill of Materials for: Power supply PWB assy 10.3 PWB: Board Area in Sq Inches: Components Part Number M51995P upc494C 2903D PC123 3050C Trace ViaTD Thick. 31.5 Qty 1 1 1 3 8 Qty. 2 2 3 3 3 4 4 3 4 3 5 2 2 2 0.02 0.012 0.048 Material Capacitor Fuse Filter Variable resistor Connector Connector Connector Connector SOT SOT SOT Misc. Discrete 1206 chip capacitor 0805 chip resistor Space ViaOD #Layers (total both sides) #IO 4 3 2 2 4 6 0.05 0.03 0.062 Weight (grams) 0.1 0.1 0.1 0.1 0.1 0.075 0.035 0.01 0.035 2 Formation Process Pitch Material Weight All Dimensions in Inches Type Pkg Variable resistor Trimmer pot Axial leaded resistor Pilot lite LED Connector Connector Space ViaOD #Layers (1 side only) #IO 16 16 8 4 3 Pitch 0.1 0.1 0.2 0.1 0.1 0.1 0.02 0.06 1 Length 0.95 0.2 Pitch Material Weight All Dimensions in Inches Type Pkg DTP DTP DTP DTP To-220 Pitch 0.1 0.1 0.1 0.1 0.1 Length 0.9 0.9 0.3 0.2 0.75 Features 0.03 FR4 27 Width 0.65 0.2 0.07 Phenolic 240 Width 0.2 0.2 0.2 0.2 0.4 Supplier Finish (top) Finish (bottom) 63 ------- Appendix E Cannon FPD - Detailed BOM Sub No. Entry No. Rectifier Name 1 4 8 6 20 8 22 45 24 3 1 1 1 1 Bill of Materials for: Row driver input PWB 12.4 PWB: Board Area in Sq Inches: Components Part Number Trace VialD Thick. 24 Qty 9 3 2 Bill of Materials for: Column driver input PWB 12.3 PWB: Board Area in Sq Inches: Components Part Number Total Product Weight Trace ViaTD Thick. 18 Qty 20 10 2 Qty. 4 2 2 6 2 3 2 2 2 2 8 2 2 8 0.02 0.012 0.032 Material STP L.g. electrolytic cap Med e-lytic cap Sm e-lytic cap Radial tant cap Sm transistor Axial lead diode Axial lead resistor Wire jumper Lg ferrite core toroid Lg transformer Fuse Connector Connector Space ViaOD #Layers (total both sides) #IO 2 2 36 0.02 0.012 0.032 Weight (grams) 0.2 0.1 0.1 0.01 0.035 4 Formation Process 1.1 Pitch Material Weight All Dimensions in Inches Type Pkg 1206 chip capacitor 2515 chip capacitor Connector Space ViaOD #Layers (total both sides) #IO 2 2 36 Pitch 0.1 0.01 0.035 2 Pitch Material Weight All Dimensions in Inches Type Pkg 1206 chip capacitor 2515 chip capacitor Connector Pitch 0.1 5798.6 Stand Features 0.8 0.03 FR4 30 0.03 FR4 40 3681.4 Supplier Finish (top) Finish (bottom) 64 ------- Glossary a: Si Active center Alignment layer AMLCD Amorphous Amorphous polymers Amphiphilic Anisotropic APCVD Aquadag Backbone Biaxial Birefringence Block polymers BOM Buffing CCFT Chain polymer Amorphous silicon Location of the unpaired electron on a free radical, where reactions take place. A layer and/or surface treatment applied to the boundary of a liquid crystal cell to induce a particular director orientation. For example, a layer of polyimide buffed in one direction induces alignment parallel to the buffing direction, or a surfactant may be polymerized on a boundary surface to induce perpendicular alignment. Active-matrix liquid crystal display Irregular; having no discernible order or shape. In the context of solids, the molecules are randomly arranged, as in glass, rather than periodically arranged, as in a crystalline material. A glass-like structure with tangled chains and no long-range order. A molecule with a hydrophilic head and a hydrophobic tail (i.e., a molecule that has one end that attracts water and one end that repels water). Having properties that vary depending on the direction of measurement. In liquid crystals, this is due to the alignment and the shape of the molecules. Dielectric anisotropy means different dielectric strengths along different axes, and refractive anisotropy means different refractive indices along different axes. Atmospheric pressure chemical vapor deposition An aqueous conductive coating found on the faceplate. The main structure of a polymer onto which substituents are attached. Possesses two directions along which monochromatic light vibrating in any plane will travel with the same velocity. Also called double refraction. The property of uniaxial anisotropic materials in which light propagates at different velocities, depending on its direction of polarization relative to the optic axis. Polymers composed of two or more connected sequences (blocks) of homopolymers. Bill of materials To give the inner glass surfaces of a liquid crystal cell a texture, in order to align the liquid crystal molecules in a certain direction parallel to the surfaces. Cold cathode fluorescent tube A polymer in which the repetition of units is linear. The 65 ------- Chiral Nematic COB COF COG Convergence Cross-linking CRT Gullet CVD DfE Program Dielectric Dot pitch E/S EOL FPD Frit Gate Grille dag 1C IPS Isotropic ITO LCD Liquid crystal monomers are linked end to end, forming a single straight polymer. Similar to the nematic phase; however, in the cholesteric phase, molecules in the different layers orient at a slight angle relative to each other (rather than parallel, as in the nematic). Each consecutive molecule is rotated slightly relative to the one before it. Therefore, instead of the constant director of the nematic, the cholesteric director rotates helically throughout the sample. Chip-on-board Chip-on-film Chip-on-glass The ability of an electron beam to hit the correct phosphor dot. A process in which bonds are formed joining adjacent molecules. At low density, these bonds add to the elasticity of the polymer. At higher densities, they eventually produce rigidity in the polymers. Cathode ray tube. A glass vacuum tube used in televisions and monitors. Broken glass from CRT Chemical vapor deposition EPA's Design for the Environment Program A material that is inserted between the plates of a capacitor to increase its effective capacitance. The vertical distance between the centers of adjacent pixels. Dot pitch is an important determinant in the clarity of a color monitor. Etch stop End-of-life Flat panel display Solder glass made of lead oxide, zinc oxide, and boron oxide, mixed with nitrocellulose binder and amyl acetate to form a paste. Control terminal of a thin-film-transistor. A coating of contrast-enhancing material applied to the faceplate. Integrated circuit In-plane switching Disordered and without any preferred direction. Indium tin oxide Liquid crystal display A thermodynamic stable phase characterized by anisotropy of properties without the existence of a three-dimensional crystal lattice, generally lying in the temperature range between the solid and isotropic liquid phase. 66 ------- Mesomorphic substance Another term for a liquid crystal material. MIM Monochromatic light Nematic NMP OEM p:Si Passivation PECVD Phosphors Photoresist PMLCD Polyimide Polymer liquid crystals PVD PWB Slurry STN TAB TFT-LCD TMAH Metal-insulator metal Light composed of only one specific wavelength. Liquid crystals are characterized by long-range orientational order and the random disposition of the centers of gravity in individual molecules. Nematics may be characterized as the simplest spontaneously anisotropic liquids. N-methyl pyrrolidinone Original equipment manufacturer Polycrystalline silicon A thin-film protective layer that is applied to a glass substrate prior to LCD fabrication. It makes the surface "passive" in that no ions can migrate from the glass to the silicon film. Plasma-enhanced chemical vapor deposition Luminescent materials A photosensitive polyimide resin Passive matrix liquid crystal display A cyclopolymerized organic material capable of withstanding high temperatures (at least 300°C). Polymers that contain mesogen units and thus have liquid crystal properties. Physical vapor deposition Printed wiring board A thin paste that has solids suspended in liquids. Super-twisted nematic, a passive-matrix LCD technology Tab automated bonding Thin film transistor liquid crystal display Trimethylamine hydrochloride 67 ------- |