US3582203A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical zoom and image-rotating system
Assignee: Bell and Howell Co
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Filing: 1968-08-06
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Granted: 1971-06-01
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Expires: 1988-08-06
Abstract
Abstract Optical systems for microfilm readers or the like having image rotation capabilities and zoom lens means for selectively varying the image magnification. The optical systems include an aperture stop positioned remote from the microfilm and substantially adjacent the projection screen for maintaining constant screen brightness through a broad range of magnification.
Inventors
- 👤 Arthur Cox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:12
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/10; G03B21/11
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
224 words
An optical system for a cabinet-type microfilm projector comprising the following parts operatively aligned on an optical axis: (1) a light source and mirror unit; (2) a condenser; (3) a film gate through which the condenser is adapted to direct light from the lamp; (4) a prime lens for projecting an image of film placed in the film gate; (5) a zoom lens having a movable zooming member for varying the magnification through a range of at least 1.33 to 1 at the option of the user; (6) a combined angle spreader and image rotation unit consisting of a positive lens component adjacent the zoom lens, a negative lens component spaced therefrom and a pechan-type inverting prism therebetween having two closely spaced internal faces through which the light beam passes, the whole unit being mounted for rotation around the optical axis; (7) a system of three mirrors for folding the projected beam of rays forming said image and (8) a fine grain diffusing screen upon which the projected image may be viewed, characterized by having the aperture stop for the projection system between the closely spaced faces of the pechan prism and by a lens component of the condenser being movable under the control of the movement of the zooming member of the zoom lens whereby optimum illumination is maintained throughout the zooming range.
Claim 2
Dependent Claim
224 words
An optical system for a cabinet-type microfilm projector comprising the following parts operatively aligned on an optical axis: (1) a light source and mirror unit; (2) a condenser; (3) a film gate through which the condenser is adapted to direct light from the lamp; (4) a prime lens for projecting an image of film placed in the film gate; (5) a zoom lens having a movable zooming member for varying the magnification through a range of at least 1.33 to 1 at the option of the user; (6) a combined angle spreader and image rotation unit consisting of a positive lens component adjacent the zoom lens, a negative lens component spaced therefrom and a pechan-type inverting prism therebetween having two closely spaced internal faces through which the light beam passes, the whole unit being mounted for rotation around the optical axis; (7) a system of three mirrors for folding the projected beam of rays forming said image and (8) a fine grain diffusing screen upon which the projected image may be viewed, characterized by having the aperture stop for the projection system between the closely spaced faces of the pechan prism and by a lens component of the condenser being movable under the control of the movement of the zooming member of the zoom lens whereby optimum illumination is maintained throughout the zooming range.
Claim 3
Dependent Claim
51 words
An optical system as claimed in claim 1, further characterized by having one of the three mirrors mounted for optional movement to a position outside the projected beam whereby the image is projected to an alternative image position and by having means for supporting photosensitized paper in said alternative image position.
Claim 4
Dependent Claim
174 words
An optical system comprising the following parts operatively aligned on an optical axis: (1) a light source; (2) a condenser; (3) a film gate through which the condenser is adapted to direct light from said source; (4) a prime lens for projecting an image of film placed in the film gate; (5) a zoom lens having a movable zooming member for varying the magnification of said image; (6) a combined angle spreader and image rotation unit consisting of a positive lens component adjacent to the zoom lens, a negative lens component spaced therefrom and a pechan-type inverting prism, the whole unit being mounted for rotation around the optical axis; and (7) a screen disposed in the light path upon which the projected image may be viewed wherein said optical system is characterized by an aperture stop between the closely spaced faces of the pechan prism and movement of a lens component of the condenser responsive to movement of the zooming member of the zoom lens whereby constant illumination is maintained throughout the zooming range.
Claim 5
Dependent Claim
174 words
An optical system comprising the following parts operatively aligned on an optical axis: (1) a light source; (2) a condenser; (3) a film gate through which the condenser is adapted to direct light from said source; (4) a prime lens for projecting an image of film placed in the film gate; (5) a zoom lens having a movable zooming member for varying the magnification of said image; (6) a combined angle spreader and image rotation unit consisting of a positive lens component adjacent to the zoom lens, a negative lens component spaced therefrom and a pechan-type inverting prism, the whole unit being mounted for rotation around the optical axis; and (7) a screen disposed in the light path upon which the projected image may be viewed wherein said optical system is characterized by an aperture stop between the closely spaced faces of the pechan prism and movement of a lens component of the condenser responsive to movement of the zooming member of the zoom lens whereby constant illumination is maintained throughout the zooming range.
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) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |