# US 2013/0154469 A1 · Cathode body, fluorescent tube, and method of manufacturing a cathode body

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- Number: US 2013/0154469 A1
- Document ID: US20130154469A1
- Status: Published application
- Kind: A1
- Application number: 13/819,476
- Filed: 2011-08-30
- Published: 2013-06-20
- Earliest claimed: 2010-09-01
- Assignees: National University Corporation Tohoku University
- Inventors: Tadahiro Ohmi; Tetsuya Goto; Hidekazu Ishii
- Web page: https://patentgrep.com/patent/US20130154469A1

## CPC

- H01J 1/30: Cold cathodes, e.g. field-emissive cathode
- H01J 9/022: {of cold cathodes}
- H01J 61/0675: {characterised by the material of the electrode}
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

Provided is a cathode body that comprises a cylindrical cup 30 as a base member, a barrier layer 303 provided on a surface of the cylindrical cup 30 and containing SiC, and a film formed on a surface of the barrier layer 303 and containing a boride of a rare earth element and that can prevent interdiffusion of a constituent element of the base member and the boride.

## Claims

### Claim 1

A cathode body by comprising:
a base member;
a barrier layer provided on a surface of the base member and containing SiC; and
a film formed on a surface of the barrier layer and containing a boride of a rare earth element.

### Claim 2 (depends on 1)

The cathode body according to claim 1, wherein:
the base member is tungsten, molybdenum, silicon, or tungsten or molybdenum containing at least one selected from the group consisting of La2O3, ThO2, and Y2O3.

### Claim 3 (depends on 1)

The cathode body according to claim 1, wherein:
the boride of the rare earth element contains at least one boride selected from the group consisting of LaB4, LaB6, YbB6, GaB6, and CeB6.

### Claim 4 (depends on 3)

The cathode body according to claim 3, wherein:
the at least one boride of the rare earth element selected is LaB6.

### Claim 5 (depends on 4)

The cathode body according to claim 4, wherein:
the base member is tungsten or tungsten containing 4 to 6% La2O3 by volume ratio.

### Claim 6 (depends on 1)

A fluorescent tube using, as a cathode, the cathode body according to claim 1.

### Claim 7

A method of manufacturing a cathode body, comprising:
a step (a) of forming a barrier layer containing SiC on a surface of a base member; and
a step (b) of forming a film containing a boride of a rare earth element on the barrier layer.

### Claim 8 (depends on 7)

The method of manufacturing a cathode body according to claim 7, wherein:
the step (a) is a step of forming the barrier layer on the surface of the base member by CVD or sputtering.

### Claim 9 (depends on 7)

The method of manufacturing a cathode body according to claim 7, wherein:
the step (b) is a step of forming the film of LaB6 on the barrier layer by sputtering.

### Claim 10 (depends on 7)

The method of manufacturing a cathode body according to claim 7, wherein:
the base member is tungsten, molybdenum, silicon, or tungsten or molybdenum containing 4 to 6 wt % lanthanum oxide.

### Claim 11 (depends on 3)

The cathode body according to claim 3, wherein:
the base member is tungsten, molybdenum, silicon, or tungsten or molybdenum containing at least one selected from the group consisting of La2O3, ThO2, and Y2O3.

### Claim 12 (depends on 8)

The method of manufacturing a cathode body according to claim 8, wherein:
the step (b) is a step of forming the film of LaB6 on the barrier layer by sputtering.

### Claim 13 (depends on 8)

The method of manufacturing a cathode body according to claim 8, wherein:
the base member is tungsten, molybdenum, silicon, or tungsten or molybdenum containing 4 to 6 wt % lanthanum oxide.