# US 5,348,827 A · Plate material for shadow mask

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- Number: US 5,348,827 A
- Document ID: US5348827A
- Status: Granted
- Kind: A
- Application number: 07/692,454
- Filed: 1991-04-25
- Granted: 1994-09-20
- Earliest claimed: 1990-04-26
- Assignees: Dai Nippon Printing Co., Ltd.
- Inventors: Tsutomu Hatano
- Web page: https://patentgrep.com/patent/US5348827A

## CPC

- H01J 29/07: Shadow masks for colour television tubes
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

A plate material for a shadow mask, consisting essentially of iron or of iron and nickel and having a surface configuration which stabilizes the adhesion between the plate material and a photoresist and improves the adhesion between the plate material and a negative pattern in the process of producing a shadow mask, thereby enabling improvements in the quality and the productivity, and which causes no annealing adhesion in the shadow mask softening annealing step in the process of producing a color picture tube. The plate material has a surface roughness Ra and a surface roughness projection condition Rsk, which are defined as follows: Ra: from 0.3 to 0.8.mu.m Rsk: +0.1 or more where Ra is the surface roughness specified in JIS B 0601, and Rsk is a value representative of the relativity of an amplitude distribution curve to a mean line, i.e., the projection condition expressed by ##EQU1## where Y(i) is a roughness curve obtained within a reference length of a sectional curve when the mean line and the direction of vertical magnification are assumed to be the X-axis and the Y-axis, respectively; Rq is a quadratic mean roughness; n=230; and j=2 to 5.

## Claims

### Claim 1

A plate material for a shadow mask used in a color picture tube, having a surface roughness Ra and a surface roughness projection condition Rsk, which are defined as follows:
Ra: from 0.3 to 0.8.mu.m
Rsk: +0.1 or more
where Ra is the surface roughness specified in JIS B 0601, and Rsk is a value representative of the relativity of an amplitude distribution curve to a mean line, i.e., the projection condition expressed by ##EQU3## where Y(i) is a roughness curve obtained within a reference length of a sectional curve when the mean line and the direction of vertical magnification are assumed to be the X-axis and the Y-axis, respectively; Rq is a quadratic mean roughness; n=230; and j=2 to 5.

### Claim 2 (depends on 1)

A plate material for a shadow mask according to claim 1, which consists essentially of iron or of iron and nickel.

### Claim 3 (depends on 2)

A plate material for a shadow mask according to claim 2, wherein said surface roughness Ra and said surface roughness projection condition Rsk are within the following ranges:
Ra: 0.55 to 0.65 .mu.m
Rsk: +0.7 or more.

### Claim 4 (depends on 3)

A shadow mask which is formed from the plate material defined in claim 3.

### Claim 5 (depends on 2)

A shadow mask which is formed from the plate material defined in claim 2.

### Claim 6 (depends on 1)

A plate material for a shadow mask according to claim 1, wherein said surface roughness Ra and said surface roughness projection condition Rsk are within the following ranges:
Ra: 0.55 to 0.65.mu.m
Rsk: +0.7 or more.

### Claim 7 (depends on 6)

A shadow mask which is formed from the plate material defined in claim 6.

### Claim 8 (depends on 1)

A shadow mask which is formed from the plate material defined in claim 1.