Flat panel devices have a brighter future

By Jeanne Erdmann

An immense full-colour, high-resolution LED
screen looks out over New York's Times
Square

Everwhere you can find monitors, television screens, light bulbs, navigations systems, sporting events and billboards, they're getting bigger, brighter and flatter. That's due to LEDs (light emitting diodes) which are low-power and low-maintenance light emitting sources.

In fact, the most recognizable intersection in the world sports a larger-than-life LED display. Toshiba International Corporation’s LED Display Group recently installed an immense full-colour, high-resolution video system in New York City’s Times Square. The new screen, which covers a surface of over 80 m, uses Toshiba’s TECHNOVIRTUAL technology, which creates virtual pixels by sharing LEDs with adjacent ones.

The market for LEDs seems as bright as the diodes themselves, despite the sluggish world economy. Production of LCD (liquid crystal display) televisions, has been increasing year by year, reaching 300 million sets with sales of USD 100 billion projected for 2010. The number of plasma display sets sold each year has also been increasing.

"There are many other emerging display technologies including organic LEDs, 3D displays, electronic paper displays and flexible displays," says Shigeo Mikoshiba, Chair of TC (Technical Committee) 110: Flat panel display devices.

Market research by Strategies Unlimited anticipates a growth for LEDs that could reach USD 14.9 billion in 2013

Such a universal market calls for standards that address all aspects of FPD (flat panel display) devices, terms and definitions, measuring methods and so on.

"Under these conditions TC 110 is urged to make related standards as quickly as possible to further the industrialization of the FPDs," says Mikoshiba.

Shift in technology from optoelectronics to flat panels

The IEC has been working since 1998 to standardize LEDs. A plan for standardization of semiconductor devices began under SC (Subcommittee) 47C during the IEC General Meeting that took place in that year in Houston, Texas, USA (United States of America).

In 2003, the title of SC 47C was changed from "Optoelectronics, Display and Imaging Devices" to "Flat Panel Display Devices" so that the subcommittee could focus on standards development for FPDs such as LCDs and PDPs (plasma display panels). At this time, it became the full technical committee, TC 110, as it is known now.

By 2002 worldwide FPD revenue had grown to USD 30 billion, exceeding that of CRT, which was USD 26 billion. Also in 2002, SC 47C encompassed standardization work in OLED (organic light-emitting diode) display as an emerging technology in FPDs. With technological advancement and market growth in FPDs, SC 47C was reborn as TC 110, following SMB (Standardization Management Board) approval in June 2003.

In 2008, TC 110 began writing standards for BLUs (backlight units) for advanced OLEDs, for 3D (three-dimensional), e-paper and flexible displays. Some of the earlier LCD and PDP basic standards have entered into their second maintenance cycles.

TC 110 Secretary Hideo Iwama says that the differences between the past and present are reflected in the technologies themselves and the countries where the technologies are manufactured. From 1998 to 2003, the major technologies were LCD and PDP in PCs (personal computers) and monitors. During those years, Japan manufactured 80 % of products using that technology. During the subsequent five years, LCD and PDP replaced CRT (cathode ray tube) in televisions, and OLED and LCD found a home in mobile phones and car navigation systems. South Korea and Taiwan also emerged as manufacturers, sharing the market with Japan.

Now, BLU using LED is replacing CCFLs (cold cathode fluorescent lamps). TVs are larger and displays are 3D. Manufacturing is shifting to mainland China.

The major players for writing TC 110 standards remain Japan, South Korea, and China. In 2009, TC 110 issued seven International Standards. Presently, 16 projects are progressing in various stages.

Besides the IEC, the standardization organizations that concern themselves with FPD devices include ISO (International Organization for Standardization), SEMI (Semiconductor Equipment and Materials Institute), VESA (Video Electronics Standards Association) and ICDM (International Committee for Display Metrology).

"TC 110 is exchanging information with these organizations," says Mikoshiba. "Manufacturers of display devices in, for example, Japan, Korea and China are requiring the related standards urgently. Therefore, timeliness of making the standards is one of the most essential factors".

Two critical standards that will soon enter the FDIS (Final Draft International Standard) approval stage are IEC 61747-5-2, Liquid crystal display devices - Part 5-2: Environmental, endurance and mechanical test methods - Visual Inspection of Active Matrix Colour Liquid Crystal Display Modules, and IEC 61747-6-2, Liquid crystal display devices - Part 6-2: Measuring methods for liquid crystal display modules - Reflective type. New technologies such as electronic paper displays using non-emissive technology follow latter standard’s measuring method.

Standards are relevant to both LED users and manufacturers, says IEC TC 110 Secretary, Hideo Iwama of IDTech (International Display Technology Co. Ltd.), a subsidiary of Sony Corp.

"Generally, standards provide information and communication tools," Iwama said. "For example, functional specifications between customers and manufacturers use and refer terms and functional characteristics defined in the standards to specify and compare display functions, which avoid confusion and provide correct mutual understanding of the products. Thus, TC 110 has been focusing on the standardization for terms and definitions, and measuring methods for the functional characteristics.

"From TC 110’s standard uniqueness points, there is difficulty to describe display functions and quality such as flicker, cross-talk, moving picture quality, etc., since these are perception to human eyes. However, TC 110 has been trying to specify this vague display quality, which should be most helpful to customers and end users."

A flexible technology

The 2010 International CES (Consumer Electronics Show), which was held in January in Las Vegas, Nevada, USA, shows how adaptable LEDs can be. Examples include indoor/outdoor cameras for home security and cars where they are used to detect and record impact points for accident recording. At CES, the Chicago based company, FLEx Lighting LLC, demonstrated a backlit unit for LCD TVs that couples LEDs to a film light guide that is only 0.05 cm (0.02") thick.

Two major LCD standards are about to enter
the FDIS stage

In the entertainment area, the display industry is now marketing various 3D displays.  This trend is helped by the recent release of 3-D movies and certain TV games.

At the same time, all industrial sectors are mindful of saving trees by using less paper. Such efforts are helped by the introduction of the e-paper display, which substitutes for real paper.

"The e-paper device becomes very popular especially in the countries which have good infrastructure of the electronic book contents distribution already established," explains TC 110 Assistant Secretary Tatsuya Miyazaki of Toshiba Mobile Display Co., Ltd.

For applications that need a more vivid display, OLED proves to be the next generation display device that may replace the LCD or PDP. The biggest advantage of OLED is that it involves self-emitting lights with an absence of light for black. That provides very good visibility and contrast, Miyazaki says.

LED BLU is also a key technology that will advance the performance of LCD by achieving a much higher contrast ratio, better colour reproducibility and much lower power consumption. TV sets adopting LED BLU have already lined up in the marketplace with major suppliers in 2009, and will be explosively increasing in 2010, comments Junichi Kinoshita of Harison Toshiba Lighting Corporation.

Of course, this evolution will continue to keep TC 110 quite busy. "By 2015, the share of the LED-LCD TV set will be more than 60 % in 2015, replacing the conventional LCD-TV set using CCFL BLU," says Dr. Kinoshita. "The standardization of LED BLU in a timely manner is therefore indispensable for coping with such an impact of LED technology."