Diode structure flat panel display

• US 5,449,970 A
• Filed: 12/23/1992
• Issued: 09/12/1995
• Est. Priority Date: 03/16/1992
• Status: Expired due to Term

• Current Assignee: Applied Nanotech Holdings Incorporated (Nano Magic, Inc.)
• Original Assignee: Microelectronics and Computer Technology Corporation
• Inventors: Kumar, Nalin, Xie, Chenggang
• Primary Examiner(s): O'Shea, Sandra L.
• Assistant Examiner(s): Patel, Ashok
• Application Number:
  US07/995,846
• Time in Patent Office: 993 Days
• Field of Search: 313/495, 313/496, 313/309, 313/310, 313/311, 313/336, 313/351, 313/355, 313/250, 313/253, 313/257, 313/258, 313/268, 313/292, 315/169.4, 345/37, 345/60, 345/47, 345/74, 345/75
• US Class Current: 313/495
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: H01J 1/304 Field-emissive cathodes
• CPC Class Codes: H01J 1/3042 microengineered, e.g. Spindt-type
• CPC Class Codes: H01J 2201/304 Field emission cathodes
• CPC Class Codes: H01J 2201/30426 Coatings on the emitter surface, e.g. with low work function materials
• CPC Class Codes: H01J 2201/30457 Diamond
• CPC Class Codes: H01J 2201/319 Circuit elements associated with the emitters by direct integration
• CPC Class Codes: H01J 2329/8625 Spacing members
• CPC Class Codes: H01J 2329/864 characterised by the material
• CPC Class Codes: H01J 29/085 Anode plates, e.g. for screens of flat panel displays
• CPC Class Codes: H01J 31/127 using large area or array sources, i.e. essentially a source for each pixel group
• CPC Class Codes: H01J 61/0677 characterised by the electron emissive material
• CPC Class Codes: H01J 63/06 Lamps with luminescent screen excited by the ray or stream
• CPC Class Codes: H01J 9/027 of thin film cathodes

Abstract

A matrix-addressed diode flat panel display of field emission type is described, utilizing a diode (two terminal) pixel structure. The flat panel display includes a cathode assembly having a plurality of cathodes, each cathode including a layer of cathode conductive material and a layer of a low effective work-function material deposited over the cathode conductive material and an anode assembly having a plurality of anodes, each anode including a layer of anode conductive material and a layer of cathodoluminescent material deposited over the anode conductive material, the anode assembly located proximate the cathode assembly to thereby receive charged particle emissions from the cathode assembly, the cathodoluminescent material emitting light in response to the charged particle emissions. The flat panel display further includes the capability for selectively varying field emission between the plurality of corresponding light-emitting anodes and field-emission cathodes to thereby effect an addressable grey-scale operation of the flat panel display.

Claims

1. A diode structure flat panel display, comprising:

a cathode assembly having a plurality of cathodes, each cathode including a layer of cathode conductive material and a layer of a low effective work-function material disposed over said cathode conductive material; and

an anode assembly having a plurality of anodes, each anode including a layer of anode conductive material layer of cathodoluminescent material disposed over said anode conductive material, said anode assembly located proximate said cathode assembly to thereby receive charged particle emissions from said cathode assembly, said cathodoluminescent material emitting light in response to said charged particle emissions.

2. The display as recited in claim 1 wherein said plurality of cathodes have a relatively flat emission surface comprising said low effective work-function material arranged to form a plurality of micro-crystallites.

3. The display as recited in claim 2 wherein said micro-crystallites function as charged particle emission sites.

4. The display as recited in claim 3 wherein said emission sites contain dopant atoms.

5. The display as recited in claim 4 wherein said dopant atom is carbon.

6. The display as recited in claim 3 wherein said emission sites contain of an element different from said low effective work-function material.

7. The display as recited in claim 3, wherein said charged particle emission sites are located on said relatively flat emission surface a distance away from any edges of said relatively flat emission surface.

8. The display as recited in claim 1 wherein said plurality of cathodes have micro-tipped emission surfaces.

9. The display as recited in claim 8 wherein said plurality of cathodes are randomly fabricated.

10. The display as recited in claim 8 wherein said plurality of cathodes are photolithographically fabricated.

11. The display as recited in claim 1 wherein said low effective work-function material is amorphic diamond film.

12. The display as recited in claim 1 wherein said display comprises only two terminals located proximate to said charged particle emissions, selected ones of said cathodes constituting one such terminal and corresponding selected ones of said anodes constituting the other such terminal.

13. The display as recited in claim 1 wherein electrical potentials which control said charged particle emissions are applied solely from selected corresponding ones of said cathodes and anodes.

14. A diode structure flat panel display, comprising:

a cathode assembly having a plurality of cathodes, each cathode including a layer of cathode conductive material and a layer of a low effective work-function material disposed over said cathode conductive material;

an anode assembly having a plurality of anodes, each anode including a layer of anode conductive material and a layer of cathodoluminescent material disposed over said anode conductive material; and

means for maintaining a relatively constant gap between said cathode and anode assemblies.

15. The display as recited in claim 14 wherein said gap maintaining means comprises a plurality of spacers.

16. The display as recited in claim 15 wherein each of said spacers corresponds with ones of said pluralities of cathodes and anodes.

17. The display as recited in claim 16 wherein said cathode assembly further comprises a cathode substrate under said cathode conductive material.

18. The display as recited in claim 17 wherein said cathode conductive material contains a plurality of recesses in a surface proximate said anode assembly.

19. The display as recited in claim 18 wherein said plurality of spacers are spaced-apart from said plurality of cathodes.

20. The display as recited in claim 19 wherein said recesses are adapted to receive said spacers.

21. A flat panel display, comprising:

a cathode assembly having a plurality of cathodes, each cathode including a layer of cathode conductive material and a layer of low effective work-function material disposed over said cathode conductive material, wherein said cathode assembly further comprises a cathode substrate under said cathode conductive material;

an anode assembly having a plurality of anodes, each anode including a layer of anode conductive material and a layer of cathodoluminescent material disposed over said anode conductive material; and

means for maintaining a relatively constant gap between said cathode and anode assemblies, wherein said gap maintaining means comprises a plurality of spacers, wherein each of said spacers corresponds with ones of said pluralities of cathodes and anodes, and wherein said plurality of spacers are spaced-apart from said plurality of cathodes,

wherein said cathode conductive material contains a plurality of recesses in a surface proximate said anode assembly, wherein said recesses are adapted to receive said spacers, and wherein said recesses and said spacers form a circuitous path to thereby minimize electron-induced conduction between said plurality of cathodes and anodes.

22. A diode structure flat panel display, comprising:

a cathode assembly having a plurality of cathodes, each cathode including a layer of cathode conductive material and a layer of a low effective work-function material disposed over said cathode conductive material;

an anode assembly having a plurality of anodes, each anode including a layer of anode conductive material and a layer of cathodoluminescent material disposed over said anode conductive material, said anode assembly located proximate said cathode assembly to thereby receive charged particle emissions from said cathode assembly, said cathodoluminescent material emitting light in response to said charged particle emissions; and

means for maintaining a relatively constant gap between said cathode and anode assemblies, wherein said gap maintaining means comprises a plurality of spacers, and wherein said spacers form a circuitous path to thereby minimize electron-induced conduction between said plurality of cathodes and anodes.

23. A diode structure flat panel display, comprising:

a cathode assembly having a plurality of cathodes, each cathode including a layer of cathode conductive material and a layer of a low effective work-function material disposed over said cathode conductive material, wherein said cathode assembly further comprises a cathode substrate under said cathode conductive material;

an anode assembly having a plurality of anodes, each anode including a layer of anode conductive material and a layer of cathodoluminescent material disposed over said anode conductive material; and

means for maintaining a relatively constant gap between said cathode and anode assemblies,

wherein said gap maintaining means comprises a plurality of spacers,

wherein each of said spacers corresponds with ones of said pluralities of cathodes and anodes,

wherein said cathode conductive material contains a plurality of recesses in a surface proximate said anode assembly,

wherein said plurality of spacers are spaced-apart from said plurality of cathodes,

wherein said recesses are adapted to receive said spacers,

wherein said recesses are formed within said cathode substrate so that said spacers have lengths greater than said gap between said cathode and anode assemblies, and

wherein said recesses and said spacers form a circuitous path to thereby minimize electron-induced conduction between said plurality of cathodes and anodes.