US3639769A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoconductive potentiometer using variable transmittance control strips
Assignee: Individual
•
Filing: 1969-04-10
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Granted: 1972-02-01
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Expires: 1989-04-10
Abstract
Abstract A light control member in the nature of a photographic wedge having varying light transmittance characteristics along its length, is interposed between a light source and a photoconductive cell. The light transmittance characteristics are made to vary along the length of the control member in accordance with a predetermined function of resistance. Means are provided to position the control member so that various portions thereof are placed in the light path between the light source and the cell, thereby varying the light incident on the cell in accordance with the predetermined function. In this manner, the effective resistance of the cell can be controlled in accordance with the light transmittance variation along the length of the control member, this variable resistance being usable for a desired control function.
Inventors
- 👤 William D Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:00
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/347; G01D5/34776; G01D5/34784
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
147 words
A photoconductive potentioMeter comprising first and second photoconductive cells, light source means for providing light to said cells, a separate light control strip element interposed between said light source means and each of said cells, each of said elements having a variation in light transmittance along its length in accordance with a predetermined resistance function, said strip members being similar but arranged in opposition relationship to each other, and means for simultaneously positioning both of said strip elements relative to said light source means and said cells so as to vary the light incident on said cells in accordance with said function, said cells being connected together in series, the resistance of one of said cells increasing while the resistance of the other of said cells is decreasing and the sum of the resistances of said cells remaining constant as the position of the elements is varied.
Claim 2
Dependent Claim
147 words
A photoconductive potentioMeter comprising first and second photoconductive cells, light source means for providing light to said cells, a separate light control strip element interposed between said light source means and each of said cells, each of said elements having a variation in light transmittance along its length in accordance with a predetermined resistance function, said strip members being similar but arranged in opposition relationship to each other, and means for simultaneously positioning both of said strip elements relative to said light source means and said cells so as to vary the light incident on said cells in accordance with said function, said cells being connected together in series, the resistance of one of said cells increasing while the resistance of the other of said cells is decreasing and the sum of the resistances of said cells remaining constant as the position of the elements is varied.
Claim 3
Dependent Claim
42 words
The potentiometer of claim 1 wherein said strip elements are arcuate in form and are arranged with one in internal concentric relationship with the other, said positioning means comprising means for rotatably supporting said elements and means for rotatably driving said elements.
Claim 4
Dependent Claim
27 words
The potentiometer of claim 1 and further including means for channelling the light from said light source means through said control elements to each of said cells.
Claim 5
Dependent Claim
25 words
The potentiometer of claim 2 wherein said strip elements are circular, said cells being arranged on opposite sides of the circles formed by said elements.
Claim 6
Dependent Claim
11 words
The potentiometer of claim 1 wherein said strip elements comprise photowedges.
Claim 7
Independent Claim
176 words
A device for providing a resistance which varies as a predetermined function of a mechanical motion comprising: light source means, first and second photoconductive cells, means for controlling the transmission of light from said light source means to said cells comprising first and second light control strip elements arranged in opposing relationship, said strip elements having a variation in light transmittance along their length in accordance with said predetermined function and substantially uniform light transmittance across their widths at any point therealong to provide substantially uniform illumination of the photosensitive areas of the cells, and means for positioning said strip elements relative to said light source and said cells to vary the light incident on said cells in accordance with said function, said positioning means being adapted to simultaneously position said strip elements together, said cells being connected in series whereby as said positioning means is actuated, the resistance of one of said cells increases while the resistance of the other of said cells decreases, the sum of the resistances of said two cells remaining constant.
Claim 8
Independent Claim
176 words
A device for providing a resistance which varies as a predetermined function of a mechanical motion comprising: light source means, first and second photoconductive cells, means for controlling the transmission of light from said light source means to said cells comprising first and second light control strip elements arranged in opposing relationship, said strip elements having a variation in light transmittance along their length in accordance with said predetermined function and substantially uniform light transmittance across their widths at any point therealong to provide substantially uniform illumination of the photosensitive areas of the cells, and means for positioning said strip elements relative to said light source and said cells to vary the light incident on said cells in accordance with said function, said positioning means being adapted to simultaneously position said strip elements together, said cells being connected in series whereby as said positioning means is actuated, the resistance of one of said cells increases while the resistance of the other of said cells decreases, the sum of the resistances of said two cells remaining constant.
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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) | 1975-01-31 | 1975-08-02 | 1976-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-31 | 1979-08-02 | 1980-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-31 | 1983-08-02 | 1984-02-01 | $7700.00 | Window Closed / Lapsed |