Patent Application
20050264164
The present invention relates in general to a field-emission display having a filter layer, and more particularly, to a filter structure formed on an anode electrode layer of a field mission display. The filter struck performs color separation of a white light source generated by the anode electrode layer, such that a color image can be obtained.
According to the luminescent efficiency of various colors of phosphor powders, the conventional display provides a brightness ratio of 2:7:1 for red, green and blue colors while a specific voltage is applied thereto. To satisfy a basic color temperature (9600K), the driving current is varied.
In the above display, the distance between the electron emission layer and gate layer of the cathode electrode layer is identical. Therefore, the electric field of the driving circuit is designed under the same standard to generate identical electron beam. Therefore, it is difficult to achieve a one-color standard or one-brightness performance. A complex circuit is required to provide a white light mixed by predetermined proportions of red, green and blue components. Alternatively, the driving voltage provided to each color component has to be adjusted individually to balance different luminescent efficiencies of the three primary color components. Typically, the luminescent efficiency is G:R:B=7:2:1.
The conventional cathode-ray tube (CRT) adjusts the luminescent area of each color phosphor surface or the voltage applied to the three color electron gun according to the luminescent efficiency of various colors.
The present invention provides a field-emission display having a filter formed on a light source output surface of an anode electrode layer, such that the structure of the anode electrode layer and the fabrication of the driving circuit are simplified. In addition, the luminescent efficiency of various colors of phosphor powder is no longer a factor affecting the luminescent efficiency and quality.
The field-emission display provided by the present invention comprises red, green and blue filters or light output sure formed on the anode electrode layer by screen printing or spray. When the driving surface applies a voltage to the gate conductive layer and the cathode electrode layer, an electron beam is generated from the cathode electrode layer. The electron beam impinges the white phosphor powders of the anode electrode layer to generate a white light source. The white light source is then processed by the red, green and blue filters to obtain a required color image.
The above objects and advantages of the present invention will be become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:
Referring to
The anode electrode layer 1 includes a substrate 11. Preferably, the substrate 11 is fabricated from glass. A first conductive layer 12 such as an indium-tin oxide (ITO) is formed on the substrate 11. A plurality of second conductive layers 13 is formed on the first conductive layer 12. Preferably, the second conductive layers 13 are fabricated from white phosphor powders. Each of the second conductive layers 13 and the first conductive layer 12 under the second conductive layer 13 constructs an anode electrode unit 14.
The cathode electrode layer 2 includes a substrate 21, an insulation layer 22 formed on the substrate 21, and a gate conductive layer 3 on the insulation layer 22. The substrate 21 includes a glass substrate, and the insulation layer 22 includes a dielectric layer, for example. The gate conductive layer 3 and the insulation layer 22 are perforated with a plurality of holes 23 which expose portions 23 of the substrate 21. On each portion of the exposed substrate 23, a first conductive layer 24 such as silver glue and a second conductive layer such as carbon nanotube 25 are sequentially formed. The first and second conductive layers 24 and 25 construct a plurality of cathode units 26.
The filter 4 includes a plurality of red (R) filters 41, green (G) filters 42, and blue (B) filters 43 formed on the second conductive layers 13 of the anode electrode units 14. The filter 4 includes the transmission type or reflective type filter used in liquid crystal display. The filter 4 is attached to the light output surface, that is, the second conductive layers 13 or formed by screen printing or spray.
Referring to
Therefore, the luminescent efficiency of various colors of phosphor powders is not a factor which affects the luminescence of the second conductive layers 13 of the anode electrode units 14. The anode electrode layer 1 is easily fabricated, and the driving circuit can be easily designed
Referring to
The cathode electrode layer 7 includes a substrate 71, a first insulation layer 72 formed on the substrate 71, a gate conductive layer 73 formed on the first insulation layer 72, and a second insulation layer 74 formed on the gate conductive layer 73, and a converging layer 74 formed on the second insulation layer 73. The converging layer 74, the second insulation layer 74, the gate conductive layer 72 and the first insulation layer 71 are patterned to form a plurality of holes 76 exposing portions 77 of the substrate 7. The exposed portions of substrate 77 are then covered with first conductive layers 78 and second conductive layers 79. The first and second conductive layers 78 and 79 together serve as the cathode electrode units 80.
The filter structure 9 includes red filters 91, green filters 92 and blue filters 93 covering the anode electrode units 64. The filter structure 9 includes transmission-type or reflective-type filters used in liquid crystal display. The filter structure 9 can also be applied by screen printing or spray directly on the second conductive layers 63 of the anode electrode units 64.
When the driving circuit applies a voltage across the gate conductive layer 73 and the cathode electrode units 80, an electron beam is generated from the cathode electrode units 80 towards the anode electrode units 64. Being impinged by the electron beam, the white phosphor powder on the anode electrode units 64 generates a white light in an image gray scale state. The filter structure 9 then performs color separation and/or mixing to generate a desired color image.
The filter structure 4 and 9 can also adapt the color coordinate (0.251, 0.291) for ZnS:Ag+(Zn,Cd)S:Cu,Al or (0.253, 0.311) for Y2O2S:Tb phosphor powders under 2 KV used in the conventional black-and-white cathode ray tube. Alternatively, the three color P-22 (with major component of ZnS) phosphor powders can be used.
While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those of ordinary skill in the art the various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.
