US3836772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detecting apparatus for determining when image is in focus
Assignee: Honeywell Inc
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Filing: 1973-07-18
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Granted: 1974-09-17
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Expires: 1993-07-18
Abstract
Abstract A focus detecting system includes first and second lens devices for forming first and second auxiliary images of an object on first and second detector devices, respectively. Each detector device includes a plurality of linearly displaced light responsive elements. One of the lens devices is movable with respect to its associated detector device to shift the light distribution pattern of the corresponding auxiliary image in the direction of linear displacement of the light responsive elements. The movable lens device is so coupled to a movable objective lens, which focusses a principal image of the object on a light sensitive film, that when the principal image is in focus, the light distribution patterns of the first and second images will be correspondingly positioned with respect to the first and second detector devices, respectively. A reference signal of a predetermined frequency controls a switching circuit to compare the electrical signals from the light responsive elements in the first detector device, alternately, at the predetermined frequency of the reference signal, with electrical signals provided by first and second predetermined groups of the light responsive elements in the second detector array. Signals are thereby provided which are processed and phase detected to provide an output signal representative of the direction that the objective lens is displaced from a focus position at which the principal image is in sharpest focus.
Inventors
- 👤 N Stauffer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:25
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/36
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
365 words
A focus position detecting apparatus for use with a principal lens means which is movable about a focus position at which a principal imAge of an object formed by said principal lens means is in sharp focus, the focus position detecting apparatus comprising: first means defining a first optical path for radiation from the object and for forming a first auxiliary image of said object; second means defining a second optical path for radiation from said object and for forming a second auxiliary image of said object, said second auxiliary image being spatially separated from said first auxiliary image; first and second detector means positioned to receive radiation from said first and second auxiliary images, respectively; means operable conjointly with said principal lens means for introducing relative motion between at least one of said auxiliary images and the associated detector means; said first and second detector means each including an array of light responsive elements, each light responsive element being arranged to provide an electrical signal representative of the intensity of radiation impinging thereon; means defining first and second predetermined groups of said elements in said second detector means; timing signal generating means for providing a timing signal of a predetermined frequency; means connected to said first and second detector means and responsive to said timing signal for comparing the electrical signals from said elements in said first detector means, alternately, at said predetermined frequency, with said electrical signals provided by said first and second predetermined groups of said elements in said second detector means, and providing a resultant signal for each such comparison; said array of said first detector means including a predetermined number of light responsive elements; said first and second predetermined groups of said elements of said array of said second detector means each comprising said predetermined number of distinct light responsive elements, sequential ones of said elements in said first group being arranged intersticially of corresponding sequential ones of said elements in said second group; and signal conditioning means connected to said timing signal generating means and responsive to said resultant signals for providing an output signal representative of the direction the principal lens means is displaced from said focus position.
Claim 2
Dependent Claim
365 words
A focus position detecting apparatus for use with a principal lens means which is movable about a focus position at which a principal imAge of an object formed by said principal lens means is in sharp focus, the focus position detecting apparatus comprising: first means defining a first optical path for radiation from the object and for forming a first auxiliary image of said object; second means defining a second optical path for radiation from said object and for forming a second auxiliary image of said object, said second auxiliary image being spatially separated from said first auxiliary image; first and second detector means positioned to receive radiation from said first and second auxiliary images, respectively; means operable conjointly with said principal lens means for introducing relative motion between at least one of said auxiliary images and the associated detector means; said first and second detector means each including an array of light responsive elements, each light responsive element being arranged to provide an electrical signal representative of the intensity of radiation impinging thereon; means defining first and second predetermined groups of said elements in said second detector means; timing signal generating means for providing a timing signal of a predetermined frequency; means connected to said first and second detector means and responsive to said timing signal for comparing the electrical signals from said elements in said first detector means, alternately, at said predetermined frequency, with said electrical signals provided by said first and second predetermined groups of said elements in said second detector means, and providing a resultant signal for each such comparison; said array of said first detector means including a predetermined number of light responsive elements; said first and second predetermined groups of said elements of said array of said second detector means each comprising said predetermined number of distinct light responsive elements, sequential ones of said elements in said first group being arranged intersticially of corresponding sequential ones of said elements in said second group; and signal conditioning means connected to said timing signal generating means and responsive to said resultant signals for providing an output signal representative of the direction the principal lens means is displaced from said focus position.
Claim 3
Dependent Claim
145 words
The focus position detecting apparatus as set forth in claim 1 wherein said signal conditioning means includes: means responsive to said resultant signals for providing signals representative of the absolute values of said resultant signals; means for summing said signals representative of the absolute values of said resultant signals to provide a summed signal; and means for sensing the relative phase of said summed signal with respect to said timing signal to characterize said output signal in a first manner when said summed signal and said timing signal are substantially in phase, and in a second manner when said summed signal and said timing signal are substantially out of phase, said first and second characterizations being indicative of the direction said principal lens means is displaced from its focus position, said output signal being uncharacterized whenever said principal lens means is in said focus position.
Claim 4
Dependent Claim
43 words
The focus position detecting apparatus as set forth in claim 2 wherein said phase sensing means further includes means for changing the polarity of said output signal in accordance with the relative phase of said summed signal with respect to said timing signal.
Claim 5
Dependent Claim
116 words
The focus position detecting apparatus as set forth in claim 1 wherein said signal comparing means includes: a first set of switching means connected between said first and second arrays and responsive to said timing signal during a first cyclic portion of said timing signal, for connecting said elements of said first array with corresponding elements of said first group of said second array; and a second set of switching means connected between said first and secOnd arrays and responsive to said timing signal generating means, during a second cyclic period of said timing signal, for connecting said elements of said first detector means with corresponding elements of said second group of said second detector means.
Claim 6
Dependent Claim
66 words
The focus position detecting apparatus as set forth in claim 4 wherein said first and second sets of switching means each include a set of diodes, said first set of diodes being arranged to become forward biased during said first cyclic portion of said timing signal, said second set of diodes being arranged to become forward biased during said second cyclic portion of said timing signal.
Claim 7
Dependent Claim
355 words
An automatic focussing apparatus comprising: principal lens means for forming a principal image of an object; first means defining a first optical path for radiation from the object and for forming a first auxiliary image of said object; second means defining a second optical path for radiation from said object and for forming a second auxiliary image of said object, said second auxiliary image being spatially separated from said first auxiliary image; first and second detector means positioned to receive radiation from said first and second auxiliary images, respectively; means operable conjointly with said principal lens means for introducing relative motion between at least one of said auxiliary images and the associated detector means; said first and second detector means each including an array of light responsive elements, each light responsive element being arranged to provide an electrical signal representative of the intensity of radiation impinging thereon; means defining first and second predetermined groups of said elements in said second detector means; timing signal generating means for providing a timing signal of a predetermined frequency; means connected to said first and second detector means and responsive to said timing signal for comparing the electrical signals from said elements in said first detector means, alternately, at said predetermined frequency, with said electrical signals provided by said first and second predetermined groups of said elements in said second detector means, and providing a resultant signal for each such comparison; said array of said first detector means including a predetermined number of light responsive elements; said first and second predetermined groups of said elements of said array of said second detector means each comprising said predetermined number of distinct light responsive elements, sequential ones of said elements in said first group being arranged intersticially of corresponding sequential ones of said elements in said second group; signal conditioning means connected to said timing signal generating means and responsive to said resultant signals for providing an output signal representative of the direction the principal lens means is displaced from said focus position; and control means responsive to said output signal for positioning said principal lens means at said focus position.
Claim 8
Dependent Claim
355 words
An automatic focussing apparatus comprising: principal lens means for forming a principal image of an object; first means defining a first optical path for radiation from the object and for forming a first auxiliary image of said object; second means defining a second optical path for radiation from said object and for forming a second auxiliary image of said object, said second auxiliary image being spatially separated from said first auxiliary image; first and second detector means positioned to receive radiation from said first and second auxiliary images, respectively; means operable conjointly with said principal lens means for introducing relative motion between at least one of said auxiliary images and the associated detector means; said first and second detector means each including an array of light responsive elements, each light responsive element being arranged to provide an electrical signal representative of the intensity of radiation impinging thereon; means defining first and second predetermined groups of said elements in said second detector means; timing signal generating means for providing a timing signal of a predetermined frequency; means connected to said first and second detector means and responsive to said timing signal for comparing the electrical signals from said elements in said first detector means, alternately, at said predetermined frequency, with said electrical signals provided by said first and second predetermined groups of said elements in said second detector means, and providing a resultant signal for each such comparison; said array of said first detector means including a predetermined number of light responsive elements; said first and second predetermined groups of said elements of said array of said second detector means each comprising said predetermined number of distinct light responsive elements, sequential ones of said elements in said first group being arranged intersticially of corresponding sequential ones of said elements in said second group; signal conditioning means connected to said timing signal generating means and responsive to said resultant signals for providing an output signal representative of the direction the principal lens means is displaced from said focus position; and control means responsive to said output signal for positioning said principal lens means at said focus position.
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) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |