54.1:Invited Paper:A Novel Cathode for CRTs based on Hopping Electron Transport

Abstract

The Hopping Electron Cathode (HEC) is a novel low-drive electron source, which can be used in CRTs to reduce the cost of the set electronics and to improve the image quality. It is based on a self-regulating secondary emission process enabling transport of electrons over insulating surfaces. The HEC utilizes this mechanism to compress electrons coming from a large conventional cathode into a small funnel structure of insulating material. The exit of the funnel serves as a high-brightness electron source for a CRT and can be used to reduce the spot size.

Display Technology

“…In this approach electrons from each subpixel are transported in a hopping mode via secondary electron emission over the wall of a funnel placed above the subpixel emitters. The self-regulating secondary electron emission has been previously applied for a flat thin cathode-ray panel [31] and a high-brightness electron source for CRT applications [32].…”

18.4: Field Emission Display Architecture based on Hopping Electron Transport

“…To lower the potential difference required the funnel walls should preferably be covered with a material with a high secondary electron emission coefficient. The principle has been applied in a thin and flat display employing wire cathodes [1,2], as well as in the HEC-CRT electron source which was mentioned earlier [3]. In the latter case, the electron transport was demonstrated under high current densities as required in a CRT.…”

“…Especially MgO degradation under electron bombardment is a concern. For the HEC-CRT cathode, current stability was already promising [3,5]. For the HopFED funnel degradation is, due to the much lower current, expected not to be critical.…”

“…The new element is based on controlled electron transport through an insulating structure. This transport uses a self-regulating secondary electron emission process over the insulator surface and has previously been applied in both a flat thin cathode ray panel [1,2] and a high brightness electron source for CRT applications (known as the Hopping Electron Cathode (HEC) [3]) In the HopFED a funnel, similar to that used in HEC, collects the electrons from a field emission source. Due to this collecting mechanism the requirements for the electron optical beam quality at the emitter are much less strict.…”