Patent US3678835A successfully refreshed from Google Patents.
US3678835A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic focusing device for cameras and the like
Assignee: Canon Inc
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Filing: 1970-08-12
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Granted: 1972-07-25
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Expires: 1990-08-12
Abstract
Abstract Automatic focusing device for a camera has a chopper and a separator. The chopper is located in front of a deflecting device for directing two different light beams on a common photoelectric effect element. The separator is to separate into two signals the output of the photoelectric effect element which are amplified by a single AC amplifier. The separator is synchronized with the chopper.
Inventors
- 👤 Yoshiyuki Takishima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:01
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/30; G02B7/32
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
226 words
An automatic focusing device for cameras and the like comprising a chopper provided in front of a deflecting device for directing two different light beams upon a common photoelectric effect element arranged after the deflecting device in order that said two different light beams may be alternately incident upon said photoelectric effect element, an AC amplifier to amplify the output of the photoelectric effect element, a filter to cut the noise of the output from the amplifier, a separator to separate into two signals the output of the filter, the separator being in synchronism with said chopper, said device further including an electronic circuit means comprising the photoelectric effect element, the AC amplifier, a detecting circuit for feeding the output of the photoelectric effect element to the AC amplifier, the filter to filter the noise from the output of the AC amplifier, the separator synchronizing with the chopping of the inputs to the photoelectric effect element, further circuit means for reshaping the waveform of the output of the separator to be fed into a different amplifier, detecting-integral circuit means to receive the output of the reshaping circuit means and to feed the output thereof to a difference amplifier, a servo motor to receive the output of the difference amplifier through a DC amplifier for controlling the photoelectric effect element to position at the focusing reference position.
Claim 2
Dependent Claim
226 words
An automatic focusing device for cameras and the like comprising a chopper provided in front of a deflecting device for directing two different light beams upon a common photoelectric effect element arranged after the deflecting device in order that said two different light beams may be alternately incident upon said photoelectric effect element, an AC amplifier to amplify the output of the photoelectric effect element, a filter to cut the noise of the output from the amplifier, a separator to separate into two signals the output of the filter, the separator being in synchronism with said chopper, said device further including an electronic circuit means comprising the photoelectric effect element, the AC amplifier, a detecting circuit for feeding the output of the photoelectric effect element to the AC amplifier, the filter to filter the noise from the output of the AC amplifier, the separator synchronizing with the chopping of the inputs to the photoelectric effect element, further circuit means for reshaping the waveform of the output of the separator to be fed into a different amplifier, detecting-integral circuit means to receive the output of the reshaping circuit means and to feed the output thereof to a difference amplifier, a servo motor to receive the output of the difference amplifier through a DC amplifier for controlling the photoelectric effect element to position at the focusing reference position.
Claim 3
Dependent Claim
176 words
In automatic focusing device for cameras or the like, the combination which includes, means defining a light path for permitting passage of two different light beams, a chopper means provided in the light path for permitting alternate passage of each of two different light beams, a common photoelectric conversion element for each of said two different light beams, a deflecting device for directing each of said two different light beAms upon the common photoelectric conversion element and arranged such that the two different light beams may be alternately incident upon the common photoelectric conversion element, an AC amplifier connected to amplify the output of the common photoelectric conversion element, a separator connected to said amplifier to separate into two signals the output from the common photoelectric conversion element, the separator being connected to operate in synchronism with the chopper means, a motor means adapted to actuate the automatic focusing device for controlling same, and a control circuit for the control of the motor means, the control circuit being responsive to both of the separated two signals.
Claim 4
Dependent Claim
176 words
In automatic focusing device for cameras or the like, the combination which includes, means defining a light path for permitting passage of two different light beams, a chopper means provided in the light path for permitting alternate passage of each of two different light beams, a common photoelectric conversion element for each of said two different light beams, a deflecting device for directing each of said two different light beAms upon the common photoelectric conversion element and arranged such that the two different light beams may be alternately incident upon the common photoelectric conversion element, an AC amplifier connected to amplify the output of the common photoelectric conversion element, a separator connected to said amplifier to separate into two signals the output from the common photoelectric conversion element, the separator being connected to operate in synchronism with the chopper means, a motor means adapted to actuate the automatic focusing device for controlling same, and a control circuit for the control of the motor means, the control circuit being responsive to both of the separated two signals.
Claim 5
Dependent Claim
26 words
An automatic focusing device according to claim 2, which further comprises a filter means connected to cut the noise of the output from the AC amplifier.
Claim 6
Dependent Claim
17 words
An automatic focusing device according to claim 2, in which the control circuit comprises a differential amplifier.
Claim 7
Dependent Claim
28 words
An automatic focusing device according to claim 2, in which the motor means is adapted to move the photoelectric conversion element to position at a focusing reference position.
Claim 8
Dependent Claim
27 words
An automatic focusing device according to claim 2, in which the motor means is adapted to move the deflecting device to position at the focusing reference position.
Claim 9
Dependent Claim
33 words
An automatic focusing device according to claim 2, further including a photographing objective lens, said photoelectric conversion element being positioned to receive light passing through at least part of said photographing objective lens.
Claim 10
Dependent Claim
23 words
An automatic focusing device according to claim 7, in which the photographing objective lens comprises a variator and a compensator for a zoom-lens.
Claim 11
Dependent Claim
28 words
An automatic focusing device according to claim 2, in which a light source providing the two different light beams is positioned at the side of the focusing device.
Claim 12
Dependent Claim
39 words
An automatic focusing device according to claim 9, in which the motor means is adapted to move the light source to position at the focusing reference position to project a reference light beam onto an object to be focused.
Claim 13
Dependent Claim
139 words
A camera having an automatic focusing device which includes a lens system comprising a focusing lens of a zoom lens, a variator, a compensator and an image forming lens for passing the light therethrough, a chopper to chopping light beams from the affocal light path of the zoom lens, a deflecting lens to focus the light beams in the vicinity of the photoelectric effect element, a separator, a single AC amplifier to receive the output of the photoelectric effect element and to fee thus amplified signal to said separator, said separator being synchronized with the chopper, a differential amplifier connected to receive the outputs of the separator, means for applying outputs to forward it from said differential amplifier to a servo motor to rotate the motor to maintain the focusing lens of the zoom lens in the focusing position.
Claim 14
Dependent Claim
139 words
A camera having an automatic focusing device which includes a lens system comprising a focusing lens of a zoom lens, a variator, a compensator and an image forming lens for passing the light therethrough, a chopper to chopping light beams from the affocal light path of the zoom lens, a deflecting lens to focus the light beams in the vicinity of the photoelectric effect element, a separator, a single AC amplifier to receive the output of the photoelectric effect element and to fee thus amplified signal to said separator, said separator being synchronized with the chopper, a differential amplifier connected to receive the outputs of the separator, means for applying outputs to forward it from said differential amplifier to a servo motor to rotate the motor to maintain the focusing lens of the zoom lens in the focusing position.
References Cited (Backward Citations)
US3336851A
Cited
US3511155A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |