Patent US4497560A successfully refreshed from Google Patents.
US4497560A
Expired / Lapsed
US
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Control circuit for active type range finder
Assignee: Seiko Koki KK
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Filing: 1983-01-10
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Granted: 1985-02-05
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Expires: 2003-01-10
Abstract
Abstract An active type range finder has a light-emitting element which is pulsatively driven to project light pulses on an object to be photographed. A photodetector element receives the light reflected from the object and produces a photoelectric output signal proportional to the amount of received light. A light-shielding member is scanned over the light-sensitive surface of the photodetector element in correlation with the distance to the object so that the light-shielding member successively shields successive areas of the light-sensitive surface from receiving light. An a.c. amplifier amplifies the photoelectric output signal, and an integrating circuit integrates the amplified photoelectric output signal and produces an integrated d.c. signal having a negative peak value indicative of the position of the scanning light-shielding member which corresponds to the object distance. Detecting circuitry detects the negative peak value and provides a corresponding detection signal indicative of the object distance.
Inventors
- 👤 Shinji Nagaoka
- 👤 Koji Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:39
CPC Classifications
G; G03; G03B; G03B13/00; G03B13/18; G03B13/20; G01; G01C; G01C3/00; G01C3/02; G01C3/06; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/46; G01S17/48; G02; G02B; G02B7/00; G02B7/28; G02B7/30; G02B7/32
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
221 words
In a range finder of the active type in which light projecting means comprised of a light emitting element and a light projecting lens projects light on an object to be photographed and the light reflected from the object is detected and processed to detect the object distance, a control circuit for an active type range finder comprising: a photodetector element disposed to receive the light reflected from the object and produce a photoelectric output signal proportional to the amount of received light, a light shielding member for scanning over the surface of the photodetector element in correlation with the object distance to successively shield successive regions of the photodetector element surface from receiving light, a driving circuit for pulsatively driving said light emitting element, an alternating current amplifier circuit for amplifying the photoelectric output signal from said photodetector element, a detecting circuit and an integrating circuit for converting the variation of the amplified photoelectric output signal into an integrated direct current signal having a negative peak value corresponding to the position of the scanning light shielding member which corresponds to the object distance, a peak detecting circuit for detecting the negative peak value of the direct current signal, and an electromagnet control circuit responsive to the detection of the negative peak value for controlling the focussing of an objective lens.
Claim 2
Dependent Claim
221 words
In a range finder of the active type in which light projecting means comprised of a light emitting element and a light projecting lens projects light on an object to be photographed and the light reflected from the object is detected and processed to detect the object distance, a control circuit for an active type range finder comprising: a photodetector element disposed to receive the light reflected from the object and produce a photoelectric output signal proportional to the amount of received light, a light shielding member for scanning over the surface of the photodetector element in correlation with the object distance to successively shield successive regions of the photodetector element surface from receiving light, a driving circuit for pulsatively driving said light emitting element, an alternating current amplifier circuit for amplifying the photoelectric output signal from said photodetector element, a detecting circuit and an integrating circuit for converting the variation of the amplified photoelectric output signal into an integrated direct current signal having a negative peak value corresponding to the position of the scanning light shielding member which corresponds to the object distance, a peak detecting circuit for detecting the negative peak value of the direct current signal, and an electromagnet control circuit responsive to the detection of the negative peak value for controlling the focussing of an objective lens.
Claim 3
Dependent Claim
42 words
A control circuit for an active type range finder according to claim 1, further comprising a clamp circuit for passing an output to a next stage only when the integrated direct current signal abruptly varies by at least a constant predetermined value.
Claim 4
Dependent Claim
34 words
A control circuit for an active type range finder according to claim 1, wherein said peak detecting circuit comprises a sample and hold circuit, a differential amplifier, an integrating circuit, and a voltage comparator.
Claim 5
Dependent Claim
53 words
A control circuit for an active type range finder according to claim 1, wherein said electromagnet control circuit comprises a flip-flop and an OR gate connected to a set input of said flip-flop, said OR gate receiving an output from a positive slope detecting circuit and an output from said peak detecting circuit.
Claim 6
Dependent Claim
22 words
A control circuit for an active type range finder according to claim 1, wherein said electromagnet control circuit includes a one-shot multivibrator.
Claim 7
Dependent Claim
80 words
A control circuit for an active type range finder according to claim 1, further comprising a warning circuit having a light emitting diode and an electronic buzzer, said warning circuit being driven through an AND circuit by a scan end signal indicating that a scanning motion for distance measurement is completed, an electromagnet control signal from said electromagnet control circuit and an output from said detecting circuit, and said warning circuit receiving a signal modulated by a pulse oscillator output.
Claim 8
Independent Claim
172 words
A device for detecting the distance between an object and the device comprising: light-projecting means for projecting light pulses on an object whose distance is to be detected; light-receiving means including a light-sensitive surface for receiving light including projected light reflected from the object and producing a photoelectric output signal proportional to the amount of light being received by the light-sensitive surface; scanning means including a light-shielding member for scanning the light-shielding member over the light-sensitive surface in correlation with the distance to the object so that the light-shielding member successively shields successive areas of the light-sensitive surface from receiving light; circuit means receptive of the photoelectric output signal for developing therefrom an integrated d.c. signal having a negative peak value indicative of the position of the scanning light-shielding member which corresponds to the object distance; and detecting means for detecting the negative peak value of the integrated d.c. signal and producing a corresponding detection output signal indicative of the position of the scanning light-shielding member which corresponds to the object distance.
Claim 9
Independent Claim
172 words
A device for detecting the distance between an object and the device comprising: light-projecting means for projecting light pulses on an object whose distance is to be detected; light-receiving means including a light-sensitive surface for receiving light including projected light reflected from the object and producing a photoelectric output signal proportional to the amount of light being received by the light-sensitive surface; scanning means including a light-shielding member for scanning the light-shielding member over the light-sensitive surface in correlation with the distance to the object so that the light-shielding member successively shields successive areas of the light-sensitive surface from receiving light; circuit means receptive of the photoelectric output signal for developing therefrom an integrated d.c. signal having a negative peak value indicative of the position of the scanning light-shielding member which corresponds to the object distance; and detecting means for detecting the negative peak value of the integrated d.c. signal and producing a corresponding detection output signal indicative of the position of the scanning light-shielding member which corresponds to the object distance.
Claim 10
Dependent Claim
57 words
A device according to claim 7; wherein the circuit means comprises an a.c. amplifier for amplifying the photoelectric output signal, and integrating circuit means for integrating the amplified photoelectric output signal and producing an integrated d.c. signal having a negative peak value indicative of the position of the scanning light-shielding member which corresponds to the object distance.
Claim 11
Dependent Claim
20 words
A device according to claim 8; wherein the circuit means includes a d.c. amplifier for amplifying the integrated d.c. signal.
Claim 12
Dependent Claim
26 words
A device according to claim 8; wherein the detecting means comprises a peak detecting circuit for detecting the negative peak value of the integrated d.c. signal.
Claim 13
Dependent Claim
80 words
A device according to claim 8; further comprising a movable control member movable in synchronism with the scanning movement of the light-shielding member such that the position of the control member corresponds to the object distance; and electromagnet control circuit means responsive to the detection output signal for arresting the movement of the control member during the course of the scanning movement of the light-shielding member so that the arrested position of the control member corresponds to the object distance.
Claim 14
Dependent Claim
80 words
A device according to claim 7; further comprising a movable control member movable in synchronism with the scanning movement of the light-shielding member such that the position of the control member corresponds to the object distance; and electromagnet control circuit means responsive to the detection output signal for arresting the movement of the control member during the course of the scanning movement of the light-shielding member so that the arrested position of the control member corresponds to the object distance.
Claim 15
Dependent Claim
26 words
A device according to claim 7; wherein the detecting means comprises a peak detecting circuit for detecting the negative peak value of the integrated d.c. signal.
Claim 16
Independent Claim
176 words
A device for detecting the distance between an object and the device comprising: light-projecting means for projecting light pulses on an object whose distance is to be detected; light-receiving means including an elongate light-sensitive surface having at its center portion a non-light-sensitive zone for receiving light including projected light reflected from the object and producing a photoelectric output signal proportional to the amount of light being received by the light-sensitive surface; scanning means for effecting scanning movement of the light-sensitive surface in correlation with the distance to the object so that the non-light-sensitive zone successively moves across the path of light received by the light-receiving means; circuit means receptive of the photoelectric output signal for developing therefrom an integrated d.c. signal having a negative peak value indicative of the position of the scanning light-shielding member which corresponds the object distance; and detecting means for detecting the negative peak value of the integrated d.c. signal and producing a corresponding detection output signal indicative of the position of the scanning light-shielding member which corresponds to the object distance.
Claim 17
Independent Claim
176 words
A device for detecting the distance between an object and the device comprising: light-projecting means for projecting light pulses on an object whose distance is to be detected; light-receiving means including an elongate light-sensitive surface having at its center portion a non-light-sensitive zone for receiving light including projected light reflected from the object and producing a photoelectric output signal proportional to the amount of light being received by the light-sensitive surface; scanning means for effecting scanning movement of the light-sensitive surface in correlation with the distance to the object so that the non-light-sensitive zone successively moves across the path of light received by the light-receiving means; circuit means receptive of the photoelectric output signal for developing therefrom an integrated d.c. signal having a negative peak value indicative of the position of the scanning light-shielding member which corresponds the object distance; and detecting means for detecting the negative peak value of the integrated d.c. signal and producing a corresponding detection output signal indicative of the position of the scanning light-shielding member which corresponds to the object distance.
Claim 18
Dependent Claim
57 words
A device according to claim 14; wherein the circuit means comprises an a.c. amplifier for amplifying the photoelectric output signal, and integrating circuit means for integrating the amplified photoelectric output signal and producing an integrated d.c. signal having a negative peak value indicative of the position of the scanning light-shielding member which corresponds to the object distance.
Claim 19
Dependent Claim
20 words
A device according to claim 15; wherein the circuit means includes a d.c. amplifier for amplifying the integrated d.c. signal.
Claim 20
Dependent Claim
26 words
A device according to claim 15; wherein the detecting means comprises a peak detecting circuit for detecting the negative peak value of the integrated d.c. signal.
Claim 21
Dependent Claim
80 words
A device according to claim 15; further comprising a movable control member movable in synchronism with the scanning movement of the light-shielding member such that the position of the control member corresponds to the object distance; and electromagnet control circuit means responsive to the detection output signal for arresting the movement of the control member during the course of the scanning movement of the light-shielding member so that the arrested position of the control member corresponds to the object distance.
Claim 22
Dependent Claim
80 words
A device according to claim 14; further comprising a movable control member movable in synchronism with the scanning movement of the light-shielding member such that the position of the control member corresponds to the object distance; and electromagnet control circuit means responsive to the detection output signal for arresting the movement of the control member during the course of the scanning movement of the light-shielding member so that the arrested position of the control member corresponds to the object distance.
Claim 23
Dependent Claim
26 words
A device according to claim 14; wherein the detecting means comprises a peak detecting circuit for detecting the negative peak value of the integrated d.c. signal.
References Cited (Backward Citations)
US4291223A
Cited
US4304487A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-02-05 | 1988-08-06 | 1989-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-05 | 1992-08-06 | 1993-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-05 | 1996-08-06 | 1997-02-05 | $7700.00 | Window Closed / Lapsed |