Amorphic diamond film flat field emission cathode

• US 5,686,791 A
• Filed: 06/07/1995
• Issued: 11/11/1997
• 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): ESSERMAN, MATTHEW
• Application Number:
  US08/479,480
• Time in Patent Office: 888 Days
• Field of Search: 313/495, 313/496, 313/310, 313/311, 313/336, 315/169.4, 315/169.3
• US Class Current: 313/495
• 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 2329/00 Electron emission display panels, e.g. field emission display panels
• CPC Class Codes: H01J 2329/8625 Spacing members
• 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 63/00 Cathode-ray or electron-stream lamps
• 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: Y10T 428/292 In coating or impregnation

Abstract

A field emission cathode for use in flat panel displays is disclosed comprising a layer of conductive material and a layer of amorphic diamond film, functioning as a low effective work-function material, deposited over the conductive material to form emission sites. The emission sites each contain at least two sub-regions having differing electron affinities. Use of the cathode to form a computer screen is also disclosed along with the use of the cathode to form a fluorescent light source.

Claims

1. A display device comprising a plurality of cathodes each selectively controllable to form images on a surface of a screen, said cathodes each comprising:

a layer of conductive material; and

a layer of low effective work-function material deposited over said conductive material, said low work-function material having an emission surface comprising a plurality of distributed localized electron emission sites, wherein said emission sites at said emission surface are relatively flat.

2. The display device screen as recited in claim 1 wherein said emission sites have electrical properties which are discontinuous from each other.

3. The display device as recited in claim 1 wherein said emission surface is relatively flat.

4. The display device as recited in claim 1 wherein said sites each have at least two different electron affinities.

5. The display device as recited in claim 1 wherein each said site is under 1 micron in diameter.

6. The display device as recited in claim 1 wherein some of said low effective work-function material is amorphic diamond.