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SED technology for flat screens (1/3/2006)

By Canon

Large flat-screen televisions for digital broadcasting are currently the focus of much attention. The SED (Surface-conduction Electron-emitter Display), jointly developed by Canon and Toshiba Corporation, is a new generation of high-quality large flat-screen display, that is almost ready for practical application. Its greatest feature is the ability to produce vivid colour images that surpass conventional types of display.

Canon began SED research in 1986 and, in 1999, began joint development activities with Toshiba with the aim of commercialising an SED product. Deciding that the joint development had a definite future, Canon and Toshiba established a joint venture company, SED Inc., in October 2004.

The advent of digital Hi-Vision broadcasting and the broadband network era, along with next-generation DVDs, digital cameras and digital video camcorders, is expected to fuel the spread of high-definition, high-quality next-generation content. These trends have led to demand for larger screens and higher image quality. However, enlarging CRT (cathode ray tube) screens - today's most common display - entails making the units significantly heavier and deeper. A major challenge facing display manufacturers has been how to develop a new kind of display offering the same picture quality as a CRT, but in a slim unit.

Flat screen technology

The SED, based on a new type of flat-panel display technology, was created through the merging of Canon's proprietary electron-emission and microfabrication technologies with Toshiba's CRT technology and mass-production technologies for liquid crystal displays (LCDs) and semiconductors. Like conventional CRTs, SEDs use the collision of electrons with a phosphor-coated screen to emit light. Electron emitters, which correspond to an electron gun in a CRT, are distributed in an amount equal to the number of pixels on the display.

Comparison of the CRT and SED

The key to the electron emitters, at the heart of the SED, is an extremely narrow slit, several nanometers wide, between two electric poles. Electrons are emitted from one side of the slit when approximately 10V of electricity is applied. Some of these electrons are scattered at the other side of the slit and accelerated by the approximately 10kV voltage that is applied between the glass substrates - causing light to be emitted when they collide with the phosphor-coated glass plate.

Structure of Electron Emitter

Characteristics

Since SEDs apply the same light emission principle as CRTs, they provide dynamic colour expression, a sharp picture, and faster video response than LCDs and plasma display panels (PDPs). In addition, SEDs do not require electronic beam deflection, making it possible to manufacture screens of more than 40 inches in size that are only several centimetres thick.

Low power consumption is another main feature of the new display technology. SEDs convert electrical energy into light with a higher emission efficiency than other display types, resulting in power consumption that is two-thirds that of PDPs, and also surpasses CRTs and LCDs.

Conclusion

In addition to high brightness and high definition, the SED delivers exceptional overall image quality through its fast video-response performance, high contrast, and dynamic colour expression. These qualities, along with low power consumption, distinguish the SED as a high-definition display that ideally matches modern-day needs.

With the application of inkjet printing technology to develop a high-performance electron emitter, and a screen-printing method to produce matrix wiring, Canon and Toshiba are improving production technologies to manufacture large-screen panels at low cost. Although an SED product has yet to be launched, the first product is expected to be a 55-inch SED television set.

Canon Inc. is a leader in the fields of professional and consumer imaging equipment and information systems. Canon's extensive range of products includes copiers, inkjet and laser beam printers, cameras, video equipment, medical equipment and semiconductor-manufacturing equipment.

www.canon.com