Patent US4354737A successfully refreshed from Google Patents.
US4354737A
Expired / Lapsed
US
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Variable gain screen permitting off-axis viewing with image brightness remaining constant
Assignee: Raytheon Co
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Filing: 1980-09-29
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Granted: 1982-10-19
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Expires: 2000-09-29
Abstract
Abstract The invention is a variable gain non-Lambertian screen surface (12) for employment in a visual display system. The screen surface provides constant image brightness, independent of changes in viewing angle (22). It is therefore suitable for off-axis viewing. The screen gain continuously varies from a magnitude of one to infinity at different portions on the screen surface in such a manner that the equivalent gain preceived by an off-axis viewer (16) corresponds to the viewer perceiving constant image brightness, independent of changes in the viewing angle.
Inventors
- 👤 Martin Dotsko
- 👤 Robert E. Klemm
- 👤 David L. Peters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:10
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/54; G03B21/56
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
244 words
An off-axis viewing system that includes a non-Lambertian screen surface to provide an off-axis viewer with constant image brightness as measured by an equivalent gain, independent of changes of a viewing angle, comprising: a projector positioned at a first location to provide a projected image on said screen surface; means to define a second location which is displaced from said first location, which second location receives substantially all of the refleced light of said projected image; means to determine an off-axis viewing angle, said angle defined by a first ray that begins at said first location and ends at a third location on said screen surface, and by a second ray that begins at said second location and ends at said third location; a first portion of screen surface encompassing a first predetermined area located at a first viewing angle and having a seleced first screen gain magnitude as measured from the normal of said screen surface; a second portion of screen surface encompassing a second predetermined area located at a second viewing angle and having a selected second different screen gain magnitude as measured from the normal of said screen surface; said selected first and second screen gain magnitudes each greater than said equivalent gain to provide compensation for the diminution in image brightness caused by the variance of a viewing angle from the normal, whereby said system provides the off-axis viewer with constant image brightness independent of changes of the viewing angle.
Claim 2
Dependent Claim
244 words
An off-axis viewing system that includes a non-Lambertian screen surface to provide an off-axis viewer with constant image brightness as measured by an equivalent gain, independent of changes of a viewing angle, comprising: a projector positioned at a first location to provide a projected image on said screen surface; means to define a second location which is displaced from said first location, which second location receives substantially all of the refleced light of said projected image; means to determine an off-axis viewing angle, said angle defined by a first ray that begins at said first location and ends at a third location on said screen surface, and by a second ray that begins at said second location and ends at said third location; a first portion of screen surface encompassing a first predetermined area located at a first viewing angle and having a seleced first screen gain magnitude as measured from the normal of said screen surface; a second portion of screen surface encompassing a second predetermined area located at a second viewing angle and having a selected second different screen gain magnitude as measured from the normal of said screen surface; said selected first and second screen gain magnitudes each greater than said equivalent gain to provide compensation for the diminution in image brightness caused by the variance of a viewing angle from the normal, whereby said system provides the off-axis viewer with constant image brightness independent of changes of the viewing angle.
Claim 3
Dependent Claim
17 words
A screen surface as set forth in claim 1, wherein said screen surface is shaped generally spherically.
Claim 4
Dependent Claim
24 words
A screen surface as set forth in claim 2, wherein the image brightness has a variable equivalent screen gain value between one and infinity.
Claim 5
Dependent Claim
232 words
In an off-axis viewing system that includes a non-Lambertian screen surface a method for providing constant image brightness as measured by an equivalent gain to a viewer independent of the viewing angle comprising the steps of: (a) positioning a projector at a first location to provide a projected image on said screen surface (b) defining a second location which is displaced from said first location, which second location receives substantially all of the reflected light of said projected image; (c) determining an off-axis viewing angle, said angle defined by a first ray that begins at said first location and ends at a third location on said screen surface, and by a second ray that begins at said second location and ends at said third location; (d) providing a first portion of screen surface encompassing a first predetermined area located at a first viewing angle and having a selected first screen gain magnitude as measured from the normal of said screen surface; (e) providing a second portion of screen surface encompassing a second predetermined area located at a second viewing angle and having a selected second different screen gain magnitude as measured from the normal of said screen surface; said selected first and second screen gain magnitudes each greater than said equivalent gain and providing compensation for the diminution in image brightness caused by the variance of a viewing angle from the normal.
Claim 6
Dependent Claim
232 words
In an off-axis viewing system that includes a non-Lambertian screen surface a method for providing constant image brightness as measured by an equivalent gain to a viewer independent of the viewing angle comprising the steps of: (a) positioning a projector at a first location to provide a projected image on said screen surface (b) defining a second location which is displaced from said first location, which second location receives substantially all of the reflected light of said projected image; (c) determining an off-axis viewing angle, said angle defined by a first ray that begins at said first location and ends at a third location on said screen surface, and by a second ray that begins at said second location and ends at said third location; (d) providing a first portion of screen surface encompassing a first predetermined area located at a first viewing angle and having a selected first screen gain magnitude as measured from the normal of said screen surface; (e) providing a second portion of screen surface encompassing a second predetermined area located at a second viewing angle and having a selected second different screen gain magnitude as measured from the normal of said screen surface; said selected first and second screen gain magnitudes each greater than said equivalent gain and providing compensation for the diminution in image brightness caused by the variance of a viewing angle from the normal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-10-18 | 1986-04-19 | 1986-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-18 | 1990-04-19 | 1990-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-18 | 1994-04-19 | 1994-10-19 | $7700.00 | Window Closed / Lapsed |