Field emission screen
Field emission screens (also FED for F ield E mission D isplay) are, similar to plasma screens, relatively flat screens in which, like CRT screens, an actively glowing point is generated on a screen with a fluorescent layer by means of an electron beam .
In contrast to CRTs, however, with FEDs not the entire screen is “written” by an electron beam. Instead, separate electron sources are available for each pixel. As a result, the contrast , brightness and repetition frequency of FEDs are a lot better than CRTs.
The small thickness of the FEDs is achieved by generating the necessary electrons from cold cathodes using field emission . The electrons are accelerated with the help of emission tips with an extremely small radius of curvature of only approx. 10 nm with an overlying control grid, which results in a very high electric field . 2000-3000 tips are used per pixel. The manufacturing process for the tips is self-regulating; Only then is the high density made possible.
Recent developments in FEDs also show that an applied composite can be used in place of the difficult-to-manufacture tip. This enables further gate structures and, above all, a much simpler production of a pixel cell. Another approach is to use carbon nanotubes instead of the classic tip. They offer better emitter properties, which means that emission is possible even at lower voltages.
In December 2006, Sony founded the joint venture Field Emission Technologies Inc. together with investor Tex Gate Investment to advance the development of FED. The investment volume totaled 2.5 billion yen or the equivalent of € 15.8 million. As an alternative to OLED displays, the company initially wanted to produce the first 17-inch displays in 2009. FET planned to manufacture 10,000 FE monitors in the first year, primarily for industrial applications. However, the development was stopped due to a lack of funds.
- https://web.archive.org/web/20090403084732/http://www.fe-tech.co.jp/en/index.html engl. Field Emission Technologies Inc. website (web archive)
- https://www.itwissen.info/lex-images/aufbau-eines-fed-displays-mit-microtip-electroden.png Structure of a FED display
- Sony's Field Emission Technologies closing its doors , March 2009 announcement