US5117099A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ambient light rejecting quad photodiode sensor
Assignee: Individual
•
Filing: 1990-10-29
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Granted: 1992-05-26
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Expires: 2010-10-29
Abstract
Abstract An ambient light rejecting quad photodiode sensor having compensation diodes connected with reverse polarity to respective quadrant photodiodes within the sensor, the compensation diodes being located outside of the area of illumination. By direct connection of compensation diodes in reverse polarity to each quadrant of the quad photodiodes, a large boost in signal to noise ratio is achieved for eliminating the effects of ambient room light as well as sensor dark current.
Inventors
- 👤 Terrence C. Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:00
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/16; H04N9/28
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
68 words
A photodiode array for detecting a projected image in the presence of ambient light, comprising a plurality of image sensing photodiodes connected together in parallel with like polarity, and a plurality of further photodiodes connected in parallel with and with reverse polarity to respective ones of said image sensing photodiodes, for compensating the effects of said ambient light on and sensor dark current within said image sensing diodes.
Claim 2
Dependent Claim
68 words
A photodiode array for detecting a projected image in the presence of ambient light, comprising a plurality of image sensing photodiodes connected together in parallel with like polarity, and a plurality of further photodiodes connected in parallel with and with reverse polarity to respective ones of said image sensing photodiodes, for compensating the effects of said ambient light on and sensor dark current within said image sensing diodes.
Claim 3
Dependent Claim
18 words
The photodiode array of claim 1, wherein said plurality of image sensing photodiodes are arranged in a quadrant.
Claim 4
Dependent Claim
21 words
The photodiode array of claim 2, wherein respective ones of said further photodiodes are disposed at respective corners of said quadrant.
Claim 5
Dependent Claim
19 words
The photodiode array of claim 1, wherein said further photodiodes are substantially electrically matched with said image sensing photodiodes.
Claim 6
Dependent Claim
28 words
The photodiode array of claim 1, wherein under uniform illumination the photocurrent within said image sensing photodiodes is equal to the photocurrent within said further photodiodes within +/-10%.
Claim 7
Dependent Claim
31 words
The photodiode array of claim 1, wherein each of said image sensing and further photodiodes has an active area of approximately 0.8×0.8 mm with a metalization separation of about 0.1 mm.
Claim 8
Dependent Claim
24 words
The photodiode array of claim 3, wherein said respective ones of said further photodiodes are located within about 0.15 mm of said respective corners.
References Cited (Backward Citations)
US3045125A
Cited
US3962722A
Cited
US4441120A
Cited
US4630121A
Cited
US4683467A
Cited
US4602272A
Cited
US4642529A
Cited
US4800278A
Cited
US4659930A
Cited
US4879470A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-05-26 | 1995-11-25 | 1996-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-26 | 1999-11-25 | 2000-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-26 | 2003-11-25 | 2004-05-26 | $7700.00 | Window Closed / Lapsed |