# US 5,703,429 A · Directly heated cathode structure

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- Number: US 5,703,429 A
- Document ID: US5703429A
- Status: Granted
- Kind: A
- Application number: 08/571,479
- Filed: 1995-12-13
- Granted: 1997-12-30
- Earliest claimed: 1994-12-28
- Assignees: Samsung Display Devices Co., Ltd.
- Inventors: Chang-seob Kim; Seok-bong Son; Sang-kyun Kim; Bong-uk Jeong
- Web page: https://patentgrep.com/patent/US5703429A

## CPC

- H01J 1/28: Dispenser-type cathodes, e.g. L-cathode
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

A directly heated cathode structure includes a porous pellet impregnated with an electron radiating material, a cup-shaped container holding the porous pellet, a metal member welded to the container, and a filament between the container and the metal member, restricting thermionic emission through the base and sides of the pellet and extending the life of the cathode structure.

## Claims

### Claim 1

A directly heated cathode structure comprising:
a porous pellet impregnated with an electron radiating material;
a cup-shaped container holding said porous pellet;
a metal member welded to said container; and
a filament disposed between said container and said metal member.

### Claim 2 (depends on 1)

The directly heated cathode structure as claimed in claim 1, wherein said filament comprises a plurality of filament members arranged radially.

### Claim 3 (depends on 1)

The directly heated cathode structure as claimed in claim 1, wherein said pellet comprises at least one metal selected from the group consisting of tungsten, ruthenium, molybdenum, nickel, and tantalum.

### Claim 4 (depends on 1)

The directly heated cathode structure as claimed in claim 1, wherein said filament includes tungsten and ruthenium.

### Claim 5 (depends on 1)

The directly heated cathode structure as claimed in claim 1, wherein said filament has a diameter in the range of 0.02-0.50 mm.

### Claim 6 (depends on 2)

The directly heated cathode structure as claimed in claim 2, wherein said filament has a diameter in the range of 0.02-0.50 mm.

### Claim 7 (depends on 1)

The directly heated cathode structure as claimed in claim 1, wherein said container comprises at least one metal selected from the group consisting of molybdenum, tungsten, and tantalum.

### Claim 8 (depends on 2)

The directly heated cathode structure as claimed in claim 2, wherein said container comprises at least one metal selected from the group consisting of molybdenum, tungsten, and tantalum.

### Claim 9 (depends on 7)

The directly heated cathode structure as claimed in claim 7, wherein said container has a thickness in the range of 0.02-0.50 mm.

### Claim 10 (depends on 8)

The directly heated cathode structure as claimed in claim 8, wherein said container has a thickness in the range of 0.02-0.50 mm.

### Claim 11 (depends on 1)

The directly heated cathode structure as claimed in claim 1, wherein said metal member comprises at least one metal selected from the group consisting of molybdenum, tungsten, and tantalum.

### Claim 12 (depends on 2)

The directly heated cathode structure as claimed in claim 2, wherein said metal member comprises at least one metal selected from the group consisting of molybdenum, tungsten, and tantalum.

### Claim 13 (depends on 11)

The directly heated cathode structure as claimed in claim 11, wherein the diameter of said metal member is in the range of 0.50-2.00 mm and its thickness is in the range of 0.02-5.00 mm.

### Claim 14 (depends on 12)

The directly heated cathode structure as claimed in claim 12, wherein the diameter of said metal member is a cylinder having a diameter in a range of 0.50-2.00 mm and a thickness in the range of 0.02-5.00 mm.

### Claim 15 (depends on 1)

The directly heated cathode structure as claimed in claim 1, wherein said pellet is cylindrical.

### Claim 16 (depends on 1)

The directly heated cathode structure as claimed in claim 1, wherein said pellet has a polygonal column shape.