Flat-panel display

Type of flat panel display (FPD) Number of units 

Liquid crystal displays (LCDs) with segmented characters 1470000000 

Super-twisted nematic liquid crystal displays (STN-LCDs) 45000000 

Liquid crystal displays (AM-TFT-LCDs) with active matrix thin film transistor addressing 48000000 

Inorganic semiconductor light-emitting diodes (LEDs) 181000000 

Polymer adhesives are essential in the manufacture of flat-panel displays. Adhesives are used in fabricating the display panels, in laminating the polarizers and optical films, and in assembling the driver electronics. In particular, adhesives have played a critical role in the development of liquid-crystal displays (LCD). The durability, reliability, and functionality of state-of-the-art LCDs have been made possible by advancements in both film and paste adhesives. 

Several approaches using electrically conductive adhesives instead of solder have been explored and are proving successful. Anisotropic adhesives (See. Ch. 1), for example, have been used to connect flex circuits and cables from the separate driver circuits to the panel, avoiding the use of solder connections. More importantly, integrated-circuit chips can be bonded directly to the ITO conductor traces on the panel, a technology called chip-on-glass (COG). IC chips can be flip-chip bonded, then underfilled with a stress-free underfill adhesive, if necessary. For protection, the chips may then be encapsulated with epoxy (glob topped). 

Alternately, flip-chip devices or TAB devices may be connected using an anisotropic film adhesive which, with moderate heat and pressure, forms electrical connections between the bumps or leads of the device and the conductorpads on the panel. In using an anisotropic film adhesive, the film is first attached to the glass at 80°C-100°C under pressure of 50-100 N/cm (based on bump area) for 3-5 seconds. The protective 

UV-curing adhesives are also finding an application in flat-panel electronics. Because the panel is glass and transparent to UV light, devices can be attached with a UV-curing adhesive on the topside and, after accurate positioning, exposed to UV light from the backside ofthe panel and cured in a few seconds. 

Thermoplastic hot melt adhesives have also found use in flat-panel displays (FPDs) because of their rapid bonding and ease of reworking. 

The competition in this sector is hotting up as the advocates of the various technologies battle it out on issues of price and specification. One battle casualty has been the market for conventional CRT whose prices have been under pressure as demand has fallen due to the impact of the new 

Arguably the ultimate system, whose commercial launch may be many years away, is the Super Hi-Vision system developed by the Japanese public broadcasting system, Nippon Hoso Kyokai. This offers a 16 9 aspect ratio picture with 4320 horizontal lines The magnitude of this achievement is underlined by comparison with HD which has 1080 horizontal lines, semi-HD with 768 horizontal lines and current analogue with 625 horizontal lines. 

In the opinion of the US Consumer Electronics Association HDTV sets will outsell analogue sets by a margin of 89% in 2006 with total net sales of 15.9 million. In cash terms, digital TV sales increased by 60% to reach 17 billion in 2005 with flat panel displays, including LCD and plasma options, accounting for 40% of this figure. 

There is still strong competition from plasma displays in this market segment which could affect sales. Philips has been suffering from the downturn in demand for CRT which has culminated in the insolvency of LG Philips Displays, the world s largest manufacturer of television and computer display CRT with an estimated 25% world market share. 

Despite LG Philips problems, Sony is continuing to sell television sets with CRT in emerging markets. 

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Aluminosilicate glasses are used commercially because they can be chemically strengthened and withstand high temperatures. Thus apphcations include airplane windows, frangible containers, lamp envelopes, and flat panel display devices. 

The formation mechanism is illustrated in Fig. 5. CNT film has also been found to grow epitaxially on the surface of a (3-SiC crystal particle [29], The present method should prove to be applicable to flat panel displays or to electronic devices utilising MWCNTs,... 

Field emission applicable to flat-panel display is one of the most advanced and energetically studied applications of CNTs. The apparatus is illustrated in Fig. 12 along with pictures of closed-tips of MWCNTs. In spite of their high workfunction (4..3 eV for MWCNTs [39]), CNTs emit electrons from their tips when high voltages (100-1000 V) are applied between the metal grid of the accelerator and the CNT film which are separated by 20 im [38]. 

The paper is oiganized to describe, first, the materials that have been used in OLEDs, then the device structures that have been evaluated. After a description of the methods used to characterize and evaluate materials and devices, we summarize the current stale of understanding of the physics of device operation, followed by a discussion of the mechanisms which lead to degradation and failure. Finally, we present the issues that must be addressed to develop a viable flat-panel display technology using OLEDs. Space and schedule prevent a comprehensive review of the vast literature in this rapidly moving field. We have tried to present... 

There are difficulties in analysing conductive polymers, and information on the relationship between structure and properties somewhat difficult to obtain. These materials have already found a variety of uses, including flat panel displays, antistatic packaging and rechargeable batteries, and other applications are likely to emerge in the future. 

Despite such limitations, plasma-deposited a-C(N) H films were found to be used in a number of applications. The stress reduction induced by nitrogen incorporation [12] and consequent adhesion improvement, allowed the development of a-C(N) H antireflective coatings for Ge-based infrared detectors [13]. It was also found that N can electronically dope a-C H films, and can strongly decrease the defect density, which gives prospects on its use as a semiconductor material [14]. Nitrogen incorporation was also found to decrease the threshold electric field in electron-field emission process [15], making possible the use of a-C(N) H films as an overcoat on emission tips in flat-panel display devices [16]. 

Various forms of carbon material such as graphite, diamond, carbon nanotubes (fibers), and amorphous carbon-containing, diamond-like carbon have been compared and analyzed for their potential application in the fields of flat panel displays and lighting elements.48... 

Figure 1.1. Growth of semiconductor and flat panel display industries. [Data Source Semiconductor industry sales data from Semiconductor Industry Association (SIA) and flat panel display data from Displaysearch Corp, San Jose, CA.]...

Figure 1.2. Substrate size comparison between Si wafers and glass substrates used in flat panel displays.

Mentley, D. E. 2002. State of flat-panel display technology and future trends. Proc. IEEE 90 453 159. 

Spin 10nm-5pm Uniformity, reproducibility, excellent thickness control, low cost Requires flat substrate, high material loss Photoresists, dielectric layers, flat panel displays... 

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