Black matrix for flat panel field emission displays
A flat panel field emission device includes a black matrix formed from an electrically insulative material such as praseodymium-manganese oxide. The insulative black matrix increases image contrast and reduces power consumption. For field emission devices which utilize a switched anode for selectively activating pixels, the insulative material reduces or eliminates problems associated with short circuiting of the pixels.
1. A method of making a flat panel field emission display comprising the steps of:
providing a phosphor coating on a display screen;
arranging an emission source opposite said display screen for selectively exciting portions of said phosphor coating to generate visible light during subsequent operation; and
providing a black matrix on said screen, said black matrix being formed from praseodymium-manganese oxide;
wherein said black matrix forming step includes patterning a photoresist material on said screen to expose only those areas of the screen on which the black matrix is to be deposited; depositing said praseodymium-manganese oxide; and removing said photoresist material; and
said step of providing a phosphor coating is performed subsequent to said black matrix forming step and includes patterning a second photoresist material to expose only those areas of the screen on which said phosphor coating is to be provided; depositing said phosphor coating; and removing said second photoresist material.
2. The method of claim 1 wherein said praseodymium-manganese oxide has a high resistance such that the black matrix does not drain electrons from the emission source.
3. The method of claim 1 , wherein said emission source arranging step arranges an array of field emitter tip cathodes opposite said display screen.
4. The method of claim 3 , including the further step of providing a low potential extraction grid adjacent to said field emitter tip cathodes.
5. The method of claim 4 , wherein said low potential extraction grid is formed from a continuous electrode.
6. The method of claim 1 , wherein said praseodymium-manganese oxide is prepared by combining selected amounts of Pr 6 O 11 with a material selected from the group including MnO 2 and MnCO 3 ; and heating the resulting combination at a temperature ranging from approximately 1200° C. to 1500° C.
7. The method of claim 6 , wherein the resulting combination is heated for approximately four hours at the heating temperature.
8. The method of claim 6 , including the further step of milling the resulting combination subsequent to said heating step to yield a powder having about a 2 μm average particle size.
9. The method of claim 6 , wherein said heating temperature ranges approximately from 1250° C. to 1430° C.
10. The method of claim 9 , wherein the resulting combination is heated for approximately four hours at the heating temperature.