Flat panel displays: the rising tide


Munisamy Anandan, president, Society for Information Display (SID)

The barrier for competitive display technologies is increasing because of the substantial improvements taking place in LCD technology.

Liquid crystal display (LCD) technology has revolutionized the electronic industry, dominating nearly all applications with the exception of large outdoor displays. In 2011, the shipment forecast (number of units) for LCDs for various applications, as per DisplaySearch, are as follows: 1.1B conventional cell phones, 433M smartphones, 75M tablet PCs, and 207M TVs.

Many technologies have challenged LCDs, with the most recent threat coming from organic light-emitting diodes (OLEDs). Plasma displays have also challenged LCDs in the display market.

The barrier for competitive display technologies is increasing because of the substantial improvements taking place in LCD technology. Light-emitting diodes (LEDs) have surged forward to boost LCD performance in terms of power efficiency and slimness, coupled with enhanced reliability. Additional improvements in wide viewing angle, through the introduction of advanced high-performance in-plane switching (AH-IPS) technology, have been achieved. The response speed of liquid-crystal material is constantly improving for enhancement in picture quality.

Another significant competitive barrier to challenging technologies has been achieved through simplifying LCD manufacturing processes, thereby reducing the price of LCDs. Improvements in driving techniques have enabled LCD to penetrate the 3D TV market, while touch-enabled LCDs are finding wide applications in smartphones and tablet PCs. Improvements are also forthcoming through thin-film transistor (TFT) technology employed for driving LCD pixels, with the most recent incarnation being TFT based on indium gallium zinc oxide (IGZO).

By virtue of their inherent technology advantages, plasma displays can be utilized for large-area panels at low manufacturing costs. Thus, they are successfully competing with LCDs in the large-area TV market. Plasma TVs are becoming thinner, but their power efficiency is not adequate to compete with LCD TV. This has to do, in part, with plasma displays' low luminous efficiency, although this parameter is continuously improving. Plasma displays are also an attractive option for 3D TV applications.

OLEDs, whose advantages include self-emission of light (i.e., they require no backlight), will likely pose a substantial threat to LCDs in the future. They have already penetrated the smartphone market, capturing nearly an 18% share. OLED displays are being produced for small TVs (15-in. diagonal), although for larger sizes (32- , 42- and 55-in. diagonal), there are technical barriers to overcome. Simplified manufacturing processes, such as solution, inkjet printing, and roll-to-roll processes, are being developed, creating high potential for low-cost manufacturing. Enhancement of OLEDs' power efficiency is certain to come from phosphorescent OLED technology.

Development of flexible displays has been going on for nearly two decades, and the outlook is bright for a product incorporating them to hit the marketplace in 2012-2013. Potential applications include ePaper, eBooks, smartphones, tablet PCs and even TVs. OLED technology and electrophoretic display technology are both likely candidates to become flexible displays. Electrophoretic displays are already flexible, but when laminated over a TFT glass substrate, the display becomes rigid. Electrophoretics are the dominating display technology for application in eBook readers, closely followed by LCDs.

Solid State Technology, Volume 55, Issue 1, January 2012

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