US3766419A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cathode-ray tube with shadow mask having random web distribution
Assignee: RCA Licensing Corp
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Filing: 1972-11-10
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Granted: 1973-10-16
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Expires: 1992-11-10
Abstract
Abstract The problem of moire is eliminated by randomizing the vertical and horizontal pattern of webs between apertures of a shadow mask. A cathode ray tube is provided having a color phosphor screen structure comprising a plurality of arrays of substantially parallel lines. The lines in each array are adapted to emit light of a particular color. A shadow mask, having a plurality of substantially parallel rows of apertures that are elongated in the direction of the rows and separated from adjacent apertures in each row by webs, is spaced from the screen. The webs are randomly spaced along each row and the webs in adjacent rows are randomly displaced from one another in the direction of the rows. Alternatively, the web spacing in each row can be uniform and the rows randomly displaced from one another in the direction of the rows.
Inventors
- 👤 R Barbin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:36
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/02; H01J29/06; H01J29/07; H01J29/076
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
91 words
In a cathode-ray tube having a color phosphor line screen structure comprising a plurality of arrays of substantially parallel phosphor lines, the phosphor lines in each array being adapted to emit light of a particular color, and a shadow mask spaced from said screen, said shadow mask having a plurality of substantially parallel rows of apertures being elongated in the direction of said rows and the apertures in each row being separated by webs, the improvement comprising: said rows being randomly displaced from one another in the direction of said rows.
Claim 2
Dependent Claim
91 words
In a cathode-ray tube having a color phosphor line screen structure comprising a plurality of arrays of substantially parallel phosphor lines, the phosphor lines in each array being adapted to emit light of a particular color, and a shadow mask spaced from said screen, said shadow mask having a plurality of substantially parallel rows of apertures being elongated in the direction of said rows and the apertures in each row being separated by webs, the improvement comprising: said rows being randomly displaced from one another in the direction of said rows.
Claim 3
Dependent Claim
17 words
The cathode-ray tube as defined in claim 1 including said webs being randomly spaced along each row.
Claim 4
Dependent Claim
17 words
The Cathode-ray tube as defined in claim 1 including said webs being uniformly spaced along each row.
Claim 5
Dependent Claim
110 words
In a cathode-ray tube having a color phosphor line screen structure comprising a plurality of arrays of substantially parallel phosphor lines, the phosphor lines in each array being adapted to emit light of a particular color, and a shadow mask spaced from said screen, said shadow mask having a plurality of substantially parallel rows of apertures aligned with said phosphor lines, said apertures being elongated in the direction of said rows and the apertures in each row being separated by webs, the improvement comprising: said webs being randomly spaced along each row and all webs in adjacent rows being randomly displaced from one another in the direction of said rows.
Claim 6
Dependent Claim
110 words
In a cathode-ray tube having a color phosphor line screen structure comprising a plurality of arrays of substantially parallel phosphor lines, the phosphor lines in each array being adapted to emit light of a particular color, and a shadow mask spaced from said screen, said shadow mask having a plurality of substantially parallel rows of apertures aligned with said phosphor lines, said apertures being elongated in the direction of said rows and the apertures in each row being separated by webs, the improvement comprising: said webs being randomly spaced along each row and all webs in adjacent rows being randomly displaced from one another in the direction of said rows.
Claim 7
Dependent Claim
33 words
The cathode-ray tube as defined in claim 4, wherein the random spacing along each row is such as to provide a self-supporting mask with at least 15 percent transmission at the mask center.
Claim 8
Dependent Claim
27 words
The cathode-ray tube as defined in claim 5, wherein the random spacing between centerlines of consecutive webs is within the range of 30 mils to 90 mils.
Claim 9
Dependent Claim
20 words
The cathode-ray tube as defined in claim 6, wherein an average spacing between centerlines of consecutive webs is 60 mils.
Claim 10
Dependent Claim
32 words
The cathode-ray tube as defined in claim 4, wherein the random displacement between all webs in adjacent rows in the direction of said rows is such as to provide a self-supporting mask.
Claim 11
Dependent Claim
23 words
The cathode-ray tube as defined in claim 8, wherein the random displacement between all webs in adjacent rows is at least 10 mils.
Claim 12
Dependent Claim
20 words
The cathode-ray tube as defined in claim 4, wherein said webs have uniform length in the direction of said rows.
Claim 13
Dependent Claim
29 words
The cathode-ray tube as defined in claim 4, wherein said shadow mask is divided into a plurality of randomly interleaved areas, each area having a similar pattern of apertures.
Claim 14
Dependent Claim
22 words
The cathode-ray tube as defined in claim 11, wherein said areas are sufficiently large to maintain the random effect of web spacing.
Claim 15
Dependent Claim
16 words
The cathode-ray tube as defined in claim 12, wherein said areas are about 1 inch square.
Claim 16
Dependent Claim
30 words
The cathode-ray tube as defined in claim 11, wherein said areas interleave in the direction of said rows a distance not exceeding an average spacing between centerlines of consecutive webs.
Claim 17
Dependent Claim
133 words
In a cathode-ray tube having a color phosphor line screen structure comprising a plurality of arrays of substantially parallel phosphor lines, the phosphor lines in each array being adapted to emit light of a particular color, and a shadow mask spaced from said screen, said shadow mask having a plurality of substantially parallel rows of apertures aligned with said phosphor lines, said apertures being elongated in the direction of said rows and the apertures in each row being separated by webs, the improvement comprising: said webs being randomly spaced along each row a distance to provide a self-supporting mask with at least 15% transmission at the mask center and all webs in adjacent rows being randomly displaced from one another in the direction of said rows a distance to provide a self-supporting mask.
Claim 18
Dependent Claim
133 words
In a cathode-ray tube having a color phosphor line screen structure comprising a plurality of arrays of substantially parallel phosphor lines, the phosphor lines in each array being adapted to emit light of a particular color, and a shadow mask spaced from said screen, said shadow mask having a plurality of substantially parallel rows of apertures aligned with said phosphor lines, said apertures being elongated in the direction of said rows and the apertures in each row being separated by webs, the improvement comprising: said webs being randomly spaced along each row a distance to provide a self-supporting mask with at least 15% transmission at the mask center and all webs in adjacent rows being randomly displaced from one another in the direction of said rows a distance to provide a self-supporting mask.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |