Wire-mesh cathode

• US 5,600,200 A
• Filed: 06/07/1995
• Issued: 02/04/1997
• 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): Arana, Louis M.
• Assistant Examiner(s): Patel, Ashok
• Application Number:
  US08/479,268
• Time in Patent Office: 608 Days
• Field of Search: 313/495, 313/491, 313/513, 313/522, 313/578, 313/574, 313/627, 313/629, 313/631, 313/293, 313/302, 313/304, 313/296, 313/310, 313/311, 313/333, 313/345, 313/343 , 313/346 R, 313/346 DC, 313/357, 313/309, 313/336, 313/351, 250/493.1, 219/56, 219/552, 219/553, 257/10, 257/11, 428/606, 428/364, 428/368, 428/372, 428/375, 428/378
• US Class Current: 313/346.00R
• 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 comprises 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. The cathode may be used to form a computer screen or a fluorescent light source.

Claims

1. A wire-mesh cathode, comprising:

a plurality of intersecting rows and columns of wires, the wires being electrically joined at intersection points thereof; and

a layer of amorphic diamond film deposited on said wires, said amorphic diamond film comprising a plurality of micro-crystallite electron emission sites wherein adjacent sites have different electron affinities.

2. The cathode as recited in claim 1 wherein said sites have at least two different electron affinities.

3. The cathode as recited in claim 1 wherein each said site is under 1 micron in diameter.

4. The cathode as recited in claim 1 wherein each said site is less than or equal to 0.1 micron in diameter.

5. The cathode as recited in claim 1 wherein said emission sites contain dopant atoms.

6. The cathode as recited in claim 1 wherein said dopant atoms are carbon.

7. The cathode as recited in claim 1 wherein said emission sites have at least two different bonding structures.

8. The cathode as recited in claim 7 wherein at least one of said bonding structures is SP³.

9. The cathode as recited in claim 5 wherein said emission sites contain dopant atoms of an element that is different from said amorphic diamond film.