Patent US3744893A successfully refreshed from Google Patents.
US3744893A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Viewing device with filter means for optimizing image quality
Assignee: Eastman Kodak Co
•
Filing: 1971-03-19
•
Granted: 1973-07-10
•
Expires: 1991-03-19
Abstract
Abstract A device for viewing an image projected onto a front surface screen comprises a housing provided with a viewing opening and within which said screen is mounted. Filter means is arranged within the housing between the screen and the viewing opening so as to optimize the luminance of the image reflected by the screen when viewed by an observer through the viewing opening. The filter means in conjunction with a housing shroud which surrounds the viewing opening serve to reduce substantially the ambient light which passes through the filter means and is incident on the screen as well as the ambient light incident on the filter means and reflecting specularly therefrom toward the observer. The light balancing component of the filter means produces a higher color temperature than is possible with commercially available incandescent light sources even though it is operated at less than its rated voltage. The filter means can also include a neutral density component for improving the image brightness and contrast due to the reduced effect of ambient light. The filter means is also used to effectively seal the interior of the housing against dust and dirt from the environs.
Inventors
- 👤 J Chandler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:57
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/10; G03B21/11; G03B21/115
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
82 words
A projection viewer comprising a housing having a viewing opening, a front surface sCreen within said housing and aligned with said opening, said screen providing directional reflectance of any light incident on the front surface thereof, an optical system for projecting an image onto said screen for viewing through said opening, and light balancing filter means arranged within said housing between said opening and said screen for optimizing the luminance of the image reflected by said screen when viewed through said opening.
Claim 2
Dependent Claim
82 words
A projection viewer comprising a housing having a viewing opening, a front surface sCreen within said housing and aligned with said opening, said screen providing directional reflectance of any light incident on the front surface thereof, an optical system for projecting an image onto said screen for viewing through said opening, and light balancing filter means arranged within said housing between said opening and said screen for optimizing the luminance of the image reflected by said screen when viewed through said opening.
Claim 3
Dependent Claim
18 words
The invention of claim 1 including means for sealing said housing against dust and dirt from the environs.
Claim 4
Dependent Claim
155 words
In a viewing apparatus comprising a housing having a viewing opening and a shroud for said opening, a front surface screen arranged within said housing, said screen being generally aspherical and providing directional reflectance of any light incident on the front surface thereof, and an optical system including a source of light for illuminating an image carrier medium and for projecting an image onto said screen for viewing through said opening, the improvement comprising: light balancing filter means arranged within said housing between said viewing opening and said screen for optimizing the luminance of the image reflected by said screen when viewed through said opening, said shroud limiting ambient light incident on said filter means to that passing through said viewing opening and said filter means having at least a portion thereof curved toward said viewing opening so as to reflect ambient light incident thereon generally along lines directed toward interior surfaces of said shroud.
Claim 5
Dependent Claim
155 words
In a viewing apparatus comprising a housing having a viewing opening and a shroud for said opening, a front surface screen arranged within said housing, said screen being generally aspherical and providing directional reflectance of any light incident on the front surface thereof, and an optical system including a source of light for illuminating an image carrier medium and for projecting an image onto said screen for viewing through said opening, the improvement comprising: light balancing filter means arranged within said housing between said viewing opening and said screen for optimizing the luminance of the image reflected by said screen when viewed through said opening, said shroud limiting ambient light incident on said filter means to that passing through said viewing opening and said filter means having at least a portion thereof curved toward said viewing opening so as to reflect ambient light incident thereon generally along lines directed toward interior surfaces of said shroud.
Claim 6
Dependent Claim
117 words
In a viewing apparatus comprising a housing having a viewing opening and a shroud for said opening, a front surface screen arranged within said housing, said screen being generally aspherical and providing directional reflectance of any light incident on the front surface thereof, and an optical system including a source of light for illuminating an image carrier medium and for projecting an image onto said screen for viewing through said opening, said improvement comprising: light balancing filter means arranged within said housing between said viewing opening and said screen for compensating for the color temperature of said source of light and for optimizing the luminance of the image reflected by said screen when viewed through said opening.
Claim 7
Dependent Claim
117 words
In a viewing apparatus comprising a housing having a viewing opening and a shroud for said opening, a front surface screen arranged within said housing, said screen being generally aspherical and providing directional reflectance of any light incident on the front surface thereof, and an optical system including a source of light for illuminating an image carrier medium and for projecting an image onto said screen for viewing through said opening, said improvement comprising: light balancing filter means arranged within said housing between said viewing opening and said screen for compensating for the color temperature of said source of light and for optimizing the luminance of the image reflected by said screen when viewed through said opening.
Claim 8
Dependent Claim
32 words
The viewing apparatus in accordance with claim 4 wherein said shroud substantially limits any ambient light incident on said filter means to that reflectable by said filter means to the observers eyes.
Claim 9
Dependent Claim
19 words
The viewing apparatus in accordance with claim 4 wherein the color of said light balancing filter means is blue.
Claim 10
Dependent Claim
26 words
The viewing apparatus in accordance with claim 4 including means associated with said filter means for effecting a seal between said housing and said filter means.
Claim 11
Dependent Claim
23 words
The viewing apparatus in accordance with claim 4 wherein said light balancing filter means is generally flat throughout its entire length and width.
Claim 12
Dependent Claim
68 words
The viewing apparatus in accordance with claim 4 wherein at least part of said light balancing filter means is curved in one plane and in a direction convex toward said screen, whereby the curvature of said light balancing filter means is such that any ambient light passing through said viewing opening and incident on said light balancing filter means is reflected thereby onto interior surfaces of said shroud.
Claim 13
Dependent Claim
32 words
The viewing apparatus in accordance with claim 4 wherein said light balancing filter means comprises a light balancing filter and a neutral density filter arranged in generally contacting relation to each other.
Claim 14
Dependent Claim
30 words
The viewing apparatus in accordance with claim 10 wherein the color of said light balancing filter is blue and the maximum density factor of said density filter is about 0.4.
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) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |