Flat panel display based on diamond thin films

• US 5,551,903 A
• Filed: 10/19/1994
• Issued: 09/03/1996
• 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): Bradley, P. Austin
• Assistant Examiner(s): Knapp, Jeffrey T.
• Application Number:
  US08/326,302
• Time in Patent Office: 685 Days
• Field of Search: 445/24, 445/50, 445/51
• US Class Current: 445/24
• 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 1/316 having an electric field parallel to the surface, e.g. thin film cathodes
• 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
• CPC Class Codes: Y10S 977/891 Vapor phase deposition

Abstract

A field emission cathode is provided which includes a substrate and a conductive layer disposed adjacent the substrate. An electrically resistive pillar is disposed adjacent the conductive layer, the resistive pillar having a substantially flat surface spaced from and substantially parallel to the substrate. A layer of diamond is disposed adjacent the flat surface of the resistive pillar.

Claims

1. A method of making a field emission cathode, comprising the steps of:

depositing a layer of conductive material over a substrate;

depositioning an electrically resistive pillar over said layer of conductive material, said electrically resistive pillar having a substantially flat surface spaced from and substantially parallel to said substrate; and

depositing a layer of cathode material over said surface of said electrically resistive pillar, said layer o cathode material having a substantially flat exposed surface spaced from and substantially parallel to said substrate, wherein said cathode material has a negative electron affinity.

2. The method as recited in claim 1 wherein said substrate is glass.

3. The method as recited in claim 1, wherein said electrically resistive pillar has at least one entirely exposed sidewall extending from said layer of conductive material to said substantially flat surface of said electrically resistive pillar.

4. The method as recited in claim 1 wherein said substrate is silicon.

5. The method as recited in claim 1 wherein said layer of conductive material, said resistive pillar and said cathode material form a path for electrical current.

6. The method as recited in claim 1 wherein said resistive pillar regulates current fed to said cathode material.

7. The method as recited in claim 1 further comprising the step of:

constructing a plurality of field emission cathodes over said layer of conductive material, said field emission cathodes having interstices therebetween to produce thereby a cathode assembly.

8. The method as recited in claim 7 further comprising the step of:

depositing a spacer material in said interstices.

9. The method as recited in claim 8 wherein said spacer material is fibrous.

10. The method as recited in claim 8 further comprising the steps of:

depositing an indium tin oxide layer over a substrate of an anode assembly; and

depositing a phosphor film layer of said indium tin oxide layer to produce thereby said anode assembly.

11. The method as recited in claim 10 wherein said second substrate is a transparent material.

12. The method as recited in claim 10 wherein said phosphor film layer comprises zinc oxide.

13. The method as recited in claim 10 wherein said phosphor film layer is deposited in a pattern.

14. The method as recited in claim 13 wherein said pattern defines a line of phosphor dots.

15. The method as recited in claim 13 wherein said pattern defines rows and columns of phosphor dots.

16. The method as recited in claim 15 wherein said phosphor dots constitute pixels.

17. The method as recited in claim 10 further comprising the step of:

joining said cathode assembly to said anode assembly, said spacer material thereby contacting said phosphor film layer.

18. The method as recited in claim 17 wherein said second substrate is glass.

19. The method as recited in claim 17 wherein said joined cathode and anode assemblies form a portion of a flat panel display.

20. The method as recited in claim 19 wherein said joined cathode and anode assemblies are separated by an electrical potential provided by a diode biasing circuit.

21. A method of making a field emission cathode, comprising the steps of:

depositing a layer of conductive material over a substrate;

depositing an electrically resistive pillar over said layer of conductive material, said electrically resistive pillar having a substantially flat surface spaced from and substantially parallel to said substrate; and

depositing a layer of cathode material over said surface of said electrically resistive pillar, said layer of cathode material having a substantially flat exposed surface spaced from and substantially parallel to said substrate, wherein said conductive material layer is formed of chromium.

22. A method of making a field emission cathode, comprising the steps of:

depositing a layer of conductive material over a substrate;

depositing an electrically resistive pillar over said layer of conductive material, said electrically resistive pillar having a substantially flat surface spaced from and substantially parallel to said substrate; and

depositing a layer of cathode material over said surface of said electrically resistive pillar, said layer of cathode material having a substantially flat exposed surface spaced from and substantially parallel to said substrate, wherein an intermediate metal layer is deposited over said resistive pillar prior to said step of depositing a layer of cathode material.

23. A method of making a field emission cathode, comprising the steps of:

depositing a layer of conductive material over a substrate;

depositing an electrically resistive pillar over said layer of conductive material, said electrically resistive pillar having a substantially flat surface spaced from and substantially parallel to said substrate; and

depositing a layer of cathode material over said surface of said electrically resistive pillar, said layer of cathode material having a substantially flat exposed surface spaced from and substantially parallel to said substrate, wherein said cathode material is diamond film.

24. A method of making a field emission cathode, comprising the steps of:

depositing a layer of conductive material over a substrate;

depositing an electrically resistive pillar over said layer of conductive material, said electrically resistive pillar having a substantially flat surface spaced from and substantially parallel to said substrate; and

depositing a layer of cathode material over said surface of said electrically resistive pillar, said layer of cathode material having a substantially flat exposed surface spaced from and substantially parallel to said substrate, wherein said cathode material is an alkali metal.