US4259570A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical comparator
Assignee: HP Inc
•
Filing: 1978-11-27
•
Granted: 1981-03-31
•
Expires: 1998-11-27
Abstract
Abstract An optical comparator having a transimpedance amplifier with feedback diodes coupled to a differential pair of transistors which have transfer functions matching those of the feedback diodes provides a linear interpolated signal in response to the comparison of two light signals.
Inventors
- 👤 Mark Leonard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:18
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
208 words
An optical comparator for comparing first and second light signals comprising: a first optical detector positioned to receive the first light signal having a first light sensitive area and an output for providing a first electrical signal in response to light received at the first light sensitive area; a second optical detector positioned to receive the second lighty signal having a second light sensitive area and an output for providing a second electrical signal in response to light received at the second light sensitive area; first and second transimpedance amplifiers having inputs coupled to the outputs of the first and second optical detectors respectively, each having an output and each having an integrated circuit diode as the feedback element therein for producing first and second output signals in response to the first and second electrical signals respectively; a pair of integrated circuit transistors differentially coupled, the transistors and the integrated circuit diodes being on a common integrated circuit, the base of one transistor being coupled to the output of the first transimpedance amplifier and the base of the other transistor being coupled to the output of the second transimpedance amplifier for providing first and second differential comparison signals in response to the first and second output signals respectively.
Claim 2
Dependent Claim
208 words
An optical comparator for comparing first and second light signals comprising: a first optical detector positioned to receive the first light signal having a first light sensitive area and an output for providing a first electrical signal in response to light received at the first light sensitive area; a second optical detector positioned to receive the second lighty signal having a second light sensitive area and an output for providing a second electrical signal in response to light received at the second light sensitive area; first and second transimpedance amplifiers having inputs coupled to the outputs of the first and second optical detectors respectively, each having an output and each having an integrated circuit diode as the feedback element therein for producing first and second output signals in response to the first and second electrical signals respectively; a pair of integrated circuit transistors differentially coupled, the transistors and the integrated circuit diodes being on a common integrated circuit, the base of one transistor being coupled to the output of the first transimpedance amplifier and the base of the other transistor being coupled to the output of the second transimpedance amplifier for providing first and second differential comparison signals in response to the first and second output signals respectively.
Claim 3
Dependent Claim
22 words
An optical comparator as in claim 1 wherein the voltage to current transfer characteristics of the diodes and the transistors are matched.
Claim 4
Dependent Claim
41 words
An optical comparator as in claim 1 or 2 wherein the pair of integrated circuit transistors are coupled to a constant current source for maintaining the sum of the currents through the pair of integrated circuit transistors at a constant value.
Claim 5
Dependent Claim
33 words
An optical comparator as in claim 3 further comprising differencing means coupled to said pair of integrated circuit transistors for producing an analog signal responsive to the difference between the differential comparison signals.
Claim 6
Dependent Claim
35 words
An optical comparator as in claim 1 or 2 further comprising differencing means coupled to said pair of integrated circuit transistors for producing an analog signal responsive to the difference between the differential comparison signals.
Claim 7
Dependent Claim
16 words
An optical comparator as in claim 1 or 2 wherein said optical detectors are photo diodes.
Claim 8
Dependent Claim
14 words
An optical comparator as in claim 3 wherein said optical detectors are photo diodes.
Claim 9
Dependent Claim
14 words
An optical comparator as in claim 4 wherein said optical detectors are photo diodes.
Claim 10
Dependent Claim
14 words
An optical comparator as in claim 5 wherein said optical detectors are photo diodes.
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) | 1984-03-30 | 1984-09-29 | 1985-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-30 | 1988-09-29 | 1989-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-30 | 1992-09-29 | 1993-03-31 | $7700.00 | Window Closed / Lapsed |