# US 5,705,886 A · Cathode for plasma addressed liquid crystal display

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- Number: US 5,705,886 A
- Document ID: US5705886A
- Status: Granted
- Kind: A
- Application number: 08/361,079
- Filed: 1994-12-21
- Granted: 1998-01-06
- Earliest claimed: 1994-12-21
- Assignees: Philips Electronics North America Corporation; Tektronix, Inc.
- Inventors: Petrus Franciscus Gerardus Bongaerts; Jacob Bruinink; Adrianus Leonardus Josephus Burgmans; Henri Roger Jules Richard Van Helleputte; Babar Ali Khan; Karel Elbert Kuijk; Thomas Stanley Buzak; Kevin John Ilcisin; Paul Christopher Martin
- Web page: https://patentgrep.com/patent/US5705886A

## CPC

- H01J 17/485: {Plasma addressed liquid crystal displays [PALC]}
- G02F 1/13334: {Plasma addressed liquid crystal cells [PALC]}
- H01J 17/066: {Cold cathodes}
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

A plasma-addressed electro-optic display device having a layer of electro-optic material, data electrodes coupled to the electro-optic layer and adapted to receive data voltages for activating portions of the electro-optic layer, and a plurality of plasma channels extending generally transverse to the data electrodes for selectively switching on the electro-optic portions. The plasma channels each contain spaced elongated cathode and anode plasma electrodes and an ionizable gas filling. To improve performance, reliability and lifetime of the device, at least the cathode electrodes have surface portions of a negative electron affinity material. Preferably, the negative electron affinity material is a film of conductive or semiconductive diamond, diamond-like carbon, or aluminum nitride.

## Claims

### Claim 1

A plasma-addressed electro-optic display device comprising a layer of electro-optic material, data electrodes coupled to the electro-optic layer and adapted to receive data voltages for activating portions of the electro-optic layer, and a plurality of plasma channels extending generally transverse to the data electrodes for selectively switching on said electro-optic portions, said plasma channels each comprising spaced cathode and anode plasma electrodes and an ionizable gas filling, characterized in that the cathode electrodes have surface portions comprised of a negative electron affinity material having a conductivity of at least 10.sup.-4 mho/cm.

### Claim 2 (depends on 1)

The device of claim 1, characterized in that the cathode electrodes each comprise a conductive base and a film of the negative electron affinity material on the base.

### Claim 3 (depends on 2)

The device of claim 2, characterized in that the negative electron affinity, material film comprises a hard refractory conductive or semiconductive material.

### Claim 4 (depends on 1)

The device of claim 1, characterized in that the negative electron affinity material film has a thickness of at least 100.ANG..

### Claim 5 (depends on 1)

The device of claim 1, characterized in that the negative electron affinity material is diamond, diamond-like carbon, or aluminum nitride.

### Claim 6 (depends on 3)

The device of claim 3, characterized in that the hard refractory material is diamond, diamond-like carbon, or aluminum nitride with a conductivity of at least 10.sup.-4 mho/cm.