US4697891A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Focal length variable lens apparatus
Assignee: Canon Inc
•
Filing: 1984-08-31
•
Granted: 1987-10-06
•
Expires: 2004-08-31
Abstract
Abstract The present invention discloses a focal length variable lens apparatus in which a focal length variable lens system has a magnification varying system which, upon movement causes variation of the focal length of the entire system and a compensating system for compensating for the shift of an image plane resulting from the change of the focal length. The apparatus is provided with first computing apparatus for computing the position of the compensating system in accordance with the computed compensation obtained from information from the position of said magnification varying system moved position, second computing apparatus for computing the position of the compensating system in accordance with optically sensed image sharpness, and sequence control apparatus for initiating operation of the second computing apparatus after operation of the first computing apparatus.
Inventors
- 👤 Tohru Kawai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:12
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/282
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
208 words
A focal length variable optical apparatus, comprising: (a) a first optical system for changing the focal length by shifting its position; (b) a second optical system for compensating deviation in an image forming position caused by the shifting of the first optical system by shifting its position; (c) first computing means for computing a position to which the second optical system is to be shifted on the basis of the position to which the first optical system has been shifted, said first computing means including encoder means for detecting the position to which the first optical system has been shifted; (d) second computing means for computing a position to which the second optical system is to be shifted to perform the compensation by optically detecting the deviation of the image forming position; and (e) control means for actuating the second optical system on the basis of the computation result of the first computing means and the computation result of the second computing means, said control means shifting the position of said second optical system on the basis of the computation result of the first computing means and then shifting the position of the second optical system on the basis of the computation result of the second computing means.
Claim 2
Dependent Claim
208 words
A focal length variable optical apparatus, comprising: (a) a first optical system for changing the focal length by shifting its position; (b) a second optical system for compensating deviation in an image forming position caused by the shifting of the first optical system by shifting its position; (c) first computing means for computing a position to which the second optical system is to be shifted on the basis of the position to which the first optical system has been shifted, said first computing means including encoder means for detecting the position to which the first optical system has been shifted; (d) second computing means for computing a position to which the second optical system is to be shifted to perform the compensation by optically detecting the deviation of the image forming position; and (e) control means for actuating the second optical system on the basis of the computation result of the first computing means and the computation result of the second computing means, said control means shifting the position of said second optical system on the basis of the computation result of the first computing means and then shifting the position of the second optical system on the basis of the computation result of the second computing means.
Claim 3
Dependent Claim
23 words
An apparatus according to claim 1, wherein the control means includes electric driving means for shifting the position of the second optical system.
Claim 4
Dependent Claim
97 words
An apparatus according to claim 1, wherein the first computing means computes the position to which the second optical system is to be shifted as an average position of a position to which the second optical system is to be shifted for a position to which the first optical system is shifted when an object is to be focused is at a longest distance and a position to which the second optical system is to be shifted for a position of the first optical system when the object is to be focused is at a closest distance.
Claim 5
Dependent Claim
41 words
An apparatus according to claim 1, wherein the control means includes restriction means which prohibits the shifting of the second optical system on the basis of the computation result of the second computing means while the first optical system is shifting.
Claim 6
Dependent Claim
206 words
A focal length variable optical apparatus, comprising: (a) a first optical system for changing the focal length by shifting its position; (b) a second optical system for compensating deviation in an image forming position caused by the shifting of the first optical system by shifting its position; (c) encoder means for detecting the positions of the first optical system before and after the shifting of the same; (d) first computing means for computing a position to which the second optical system is to be shifted for the compensation on the basis of an output of the encoder means; (e) second computing means for computing a position to which the second optical system is to be shifted to perform the compensation by optically detecting the deviation of the image forming position; and (f) control means for actuating the second optical system on the basis of the computation result of the first computing means and the computation result of the second computing means, said control means shifting the position of said second optical system on the basis of the computation result of the first computing means and then shifting the position of the second optical system on the basis of the computation result of the second computing means.
Claim 7
Dependent Claim
206 words
A focal length variable optical apparatus, comprising: (a) a first optical system for changing the focal length by shifting its position; (b) a second optical system for compensating deviation in an image forming position caused by the shifting of the first optical system by shifting its position; (c) encoder means for detecting the positions of the first optical system before and after the shifting of the same; (d) first computing means for computing a position to which the second optical system is to be shifted for the compensation on the basis of an output of the encoder means; (e) second computing means for computing a position to which the second optical system is to be shifted to perform the compensation by optically detecting the deviation of the image forming position; and (f) control means for actuating the second optical system on the basis of the computation result of the first computing means and the computation result of the second computing means, said control means shifting the position of said second optical system on the basis of the computation result of the first computing means and then shifting the position of the second optical system on the basis of the computation result of the second computing means.
Claim 8
Dependent Claim
23 words
An apparatus according to claim 5, wherein the control means includes electric driving means for shifting the position of the second optical system.
Claim 9
Dependent Claim
97 words
An apparatus according to claim 5, wherein the first computing means computes the position to which the second optical system is to be shifted as an average position of a position to which the second optical system is to be shifted for a position to which the first optical system is shifted when an object is to be focused is at a longest distance and a position to which the second optical system is to be shifted for a position of the first optical system when the object is to be focused is at a closest distance.
Claim 10
Dependent Claim
41 words
An apparatus according to claim 5, wherein the control means includes restriction means which prohibits the shifting of the second optical system on the basis of the computation result of the second computing means while the first optical system is shifting.
Claim 11
Dependent Claim
208 words
A focal length variable optical system, comprising: (a) first and second optical systems for magnification variation and compensating deviation of an image forming position due to the magnification variation, said first and second optical systems performing respectively the magnification variation and the compensation by shifting their positions; (b) first computing means for computing a position to which the second optical system is to be shifted on the basis of the position to which the first optical system has been shifted, said first computing means including encoder means for detecting the position to which the first optical system has been shifted; (c) second computing means for computing a position to which the second optical system is to be shifted to perform the compensation by optically detecting the deviation of the image forming position; and (d) control means for actuating the second optical system on the basis of the computation result of the first computing means and the computation result of the second computing means, said control means shifting the position of said second optical system on the basis of the computation result of the first computing means and then shifting the position of the second optical system on the basis of the computation result of the second computing means.
Claim 12
Dependent Claim
208 words
A focal length variable optical system, comprising: (a) first and second optical systems for magnification variation and compensating deviation of an image forming position due to the magnification variation, said first and second optical systems performing respectively the magnification variation and the compensation by shifting their positions; (b) first computing means for computing a position to which the second optical system is to be shifted on the basis of the position to which the first optical system has been shifted, said first computing means including encoder means for detecting the position to which the first optical system has been shifted; (c) second computing means for computing a position to which the second optical system is to be shifted to perform the compensation by optically detecting the deviation of the image forming position; and (d) control means for actuating the second optical system on the basis of the computation result of the first computing means and the computation result of the second computing means, said control means shifting the position of said second optical system on the basis of the computation result of the first computing means and then shifting the position of the second optical system on the basis of the computation result of the second computing means.
Claim 13
Dependent Claim
23 words
An apparatus according to claim 9, wherein the control means includes electric driving means for shifting the position of the second optical system.
Claim 14
Dependent Claim
97 words
An apparatus according to claim 9, wherein the first computing means computes the position to which the second optical system is to be shifted as an average position of a position to which the second optical system is to be shifted for a position to which the first optical system is shifted when an object is to be focused is at a longest distance and a position to which the second optical system is to be shifted for a position of the first optical system when the object is to be focused is at a closest distance.
Claim 15
Dependent Claim
41 words
An apparatus according to claim 9, wherein the control means includes restriction means which prohibits the shifting of the second optical system on the basis of the computation result of the second computing means while the first optical system is shifting.
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) | 1990-10-05 | 1991-04-06 | 1991-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-05 | 1995-04-06 | 1995-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-05 | 1999-04-06 | 1999-10-06 | $7700.00 | Window Closed / Lapsed |