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Patent US3781091A successfully refreshed from Google Patents.
US3781091A
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Arrangement for rendering the structure of an optical image substantially invisible
Assignee: US Philips Corp
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Filing: 1972-07-12
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Granted: 1973-12-25
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Expires: 1992-07-12
Abstract
Abstract A device by which the structure of an optical image can be rendered substantially invisible. The optical image is made up of a plurality of light-emitting or light-deflecting elements, for example luminescent stripes of a colour television display screen, scanning lines of a television image or elements of a display panel. The arrangement comprises a light-transmitting plate which contains portions of alternately linearly varying thicknesses. This enables the modulation transfer function for the spatial frequency 1/a m 1 to be made substantially zero and for the spatial frequency 1/2a m 1 to be made a maximum.
Inventors
- 👤 E Ferguson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:15
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/72
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
131 words
Arrangement for rendering substantially invisible the structure of an optical image made up of a plurality of lightemitting elements, comprising a light-transmitting plate having portions of uniform thickness flanked on either side by portions of alternating varying thicknesses extending in at least one direction, the spacing between two successive portions of the plate being smaller than the spacing between two successive corresponding elements of the image, the portions of uniform thickness having a width of (1 - 2p)c meters and the portions of linearly varying thickness each having a width of pc meters where 0.25 < OR = p < OR = 0.30, c being an arbitrary constant, whereby a beam of light is refracted in a number of directions corresponding to the number of different varying thicknesses of the plate.
Claim 2
Dependent Claim
131 words
Arrangement for rendering substantially invisible the structure of an optical image made up of a plurality of lightemitting elements, comprising a light-transmitting plate having portions of uniform thickness flanked on either side by portions of alternating varying thicknesses extending in at least one direction, the spacing between two successive portions of the plate being smaller than the spacing between two successive corresponding elements of the image, the portions of uniform thickness having a width of (1 - 2p)c meters and the portions of linearly varying thickness each having a width of pc meters where 0.25 < OR = p < OR = 0.30, c being an arbitrary constant, whereby a beam of light is refracted in a number of directions corresponding to the number of different varying thicknesses of the plate.
Claim 3
Dependent Claim
58 words
Arrangement as claimed in claim 1, wherein the optical image in a given direction contains a substantially periodic structure, wherein the corresponding portions of the light-transmitting plate is a given direction form a substantially periodic structure, the angle between the two directions being such that the moire patterns due to the interference of the structures are substantially invisible.
Claim 4
Dependent Claim
31 words
Arrangement as claimed in claim 1, wherein the optical image contains a periodic or substantially periodic structure, and wherein the corresponding portions of the light-transmitting plate form a substantially aperiodic structure.
Claim 5
Dependent Claim
64 words
Arrangement as claimed in claim 1 wherein in order to render substantially invisible two mutually substantially perpendicular structures of an optical image the light-transmitting plate in one direction comprises parts of alternately linearly varying thicknesses, the direction of the structure of the light-transmitting plate being substantially parallel to the direction of a diagonal of the rectangles formed by the structures of the optical image.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |