A new player has entered the flat-panel TV market—the partnership of Canon Inc. and Toshiba Corporation—which has developed a surface-conduction electron-emitter display (SED) for televisions. The first model goes on sale this year.
The present flat-panel TV market comprises primarily LCD and plasma screens. Neither can match the image quality of conventional CRT televisions, while CRTs themselves are large and heavy. SED TVs, however, overcome both disadvantages, making them truly the next generation in television sets.
The light-emitting principle of SEDs is the same as that of CRTs. Electrons accelerated in a vacuum collide with a luminescent surface coated with a fluorescent material, which produces light. CRT displays use a single electron-emitting electron gun, positioned roughly between 10 cm and 40 cm away from the luminescent surface, while SEDs use a separate emitter for each pixel (for example, 1,920 by 1,080 pixels). The emitters are lined up on a glass plate, which is positioned just a few millimeters from another glass plate coated with red, green and blue florescent material. The space between the two plates is a vacuum.
Each emitter has a pair of electrodes, which emit electrons through slits made in an ultra-fine particle film. The slits are extremely narrow, just several one-millionths of a millimeter. Cannon’s special technology for manufacturing inkjet printers, which the company has developed over many years, was crucial for the production of the film.
When about 15 volts is applied between the electrodes, electrons are emitted from one side of the slit. A portion of the electrons is scattered on the opposite electrode and accelerated by voltage (about 10 kilovolts) applied between the glass plates. The electrons collide with the fluorescent material and light is emitted on the screen seen by the user.
Image Quality Rivals CRT Displays
Although SED panels themselves are just several millimeters thick (excluding the body of the television set), their image quality is superior to that of LCD and plasma displays on almost every count, including video response, contrast and color reproduction.
The response time of an SED depends on the decay characteristics of the fluorescent material. At less than one millisecond, it is shorter than LCD and plasma displays. The material is similar to that used in CRT displays, so color reproduction and video response are close to CRT levels.
Between the highest and lowest levels of brightness are the midtones, which are divided into gradation levels. Nearly 1,024 gradation levels, from black to white, are reproduced uniformly, which translates into a richly expressive picture due to smooth gradation.
Another feature is excellent contrast, because black is extremely well defined in SEDs. Brightness ranges from a black value of 0.04 cd/m2 or less, compared to 0.7 cd/m2 in LEDs, to a white value of 260 cd/ m2, or around four times that of plasma displays. As a result, contrast—the ratio of bright to and dark values—is 10,000:1, which is equivalent to that of CRT displays.
Lifespan, which had been a problem with SEDs, is now equivalent to that of CRT displays. Moreover, power consumption is only two-thirds that of LCD panels and just one-third that of plasma displays.
Top Share of Market Envisioned by 2010
Cannon and Toshiba established SED Inc. in October 2004 as a joint venture to commercialize and market SED panels. From the end of 2004 through the first half of 2005, ¥20 billion will be invested in a manufacturing facility that will begin producing a 50-inch model in August 2005. In the second half of 2005, the company intends to invest another ¥180 billion in preparation for mass production of 40-inch models that will compete directly with plasma and rear-projection TVs (which are mostly in the 40-inch class) by the end of 2006.
Full-fledged production of standalone SED panels will commence in the beginning of 2007. Monthly production will start at around 15,000 units and eventually reach about 75,000 units by the end of the year.
The global market for flat panel displays measuring at least 40 inches (102 cm) is expected to be 12 million units by 2010. The company envisions capturing a top share of around 20% to 30%. Given this scenario, the breakthrough year is anticipated to be 2007, when 40-inch plasma TVs are expected to cost roughly US$2,000 (US$700 for panels). SED Inc. forecasts its retail prices will be competitive
Even as organic electroluminescence and other formats enter the market, SED TVs are expected to increasingly rival flat-panel TVs due to their excellent picture quality and envisioned cost reductions thanks to mass production. As a result, SEDs seem certain to become yet another Japanese product to feed a hungry global market.