US4770510A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zoom lens
Assignee: Canon Inc
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Filing: 1987-10-09
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Granted: 1988-09-13
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Expires: 2007-10-09
Abstract
Abstract A zoom lens comprising, from front to rear, a first lens component for focusing having a positive refractive power, a second lens component for variation of the image magnification having a negative refractive power, a third lens component for compensation to move in unison with the second lens component, and a rear lens part having a positive refractive power, wherein the first lens component includes, from front to rear, a cemented lens I 1 of two elements of negative and positive powers and a meniscus-shaped lens I 2 of forward convexity having a positive refractive power, and the zoom lens satisfies the following conditions: 0.095<|β.sub.IIW ·β.sub.IIIW |/√Z<0.106 where β IIW <0, β IIIW >0, 2.15<|F.sub.I1 /F.sub.I2 |<2.8 where β IIW and β IIIW are the magnifications of the second and the third lens components respectively, Z is the zoom ratio, and F I1 and F I2 are the focal lengths of the lens I 1 and the lens I 2 respectively.
Inventors
- 👤 Hitoshi Mukaiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:14
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/145; G02B15/1451
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
161 words
A zoom lens comprising, from front to rear, a first lens component for focusing having a positive refractive power; a second lens component for variation of the image magnification having a negative refractive power; a third lens component for compensation to move in unison with said second lens component; and a rear lens part having a positive refractive power, wherein said first lens component includes, from front to rear, a cemented lens I 1 of two elements of negative and positive powers and a meniscus-shaped lens I 2 of forward convexity having a positive refractive power, and said zoom lens satisfies the following conditions: 0.095<|β.sub.IIW ·β.sub.IIIW |/√Z<0.106 where β IIW 0, β IIIW >0, 2.15<|F.sub.Il /F.sub.I2 |<2.8 where β IIW and β IIIW are the magnifications of said second and said third lens components respectively, Z is the zoom ratio, and F Il and F I2 are the focal lengths of said lens I 1 and said lens I 2 respectively.
Claim 2
Dependent Claim
161 words
A zoom lens comprising, from front to rear, a first lens component for focusing having a positive refractive power; a second lens component for variation of the image magnification having a negative refractive power; a third lens component for compensation to move in unison with said second lens component; and a rear lens part having a positive refractive power, wherein said first lens component includes, from front to rear, a cemented lens I 1 of two elements of negative and positive powers and a meniscus-shaped lens I 2 of forward convexity having a positive refractive power, and said zoom lens satisfies the following conditions: 0.095<|β.sub.IIW ·β.sub.IIIW |/√Z<0.106 where β IIW 0, β IIIW >0, 2.15<|F.sub.Il /F.sub.I2 |<2.8 where β IIW and β IIIW are the magnifications of said second and said third lens components respectively, Z is the zoom ratio, and F Il and F I2 are the focal lengths of said lens I 1 and said lens I 2 respectively.
Claim 3
Dependent Claim
62 words
A zoom lens according to claim 1, wherein said rear part comprises, from front to rear, a fourth lens component having a positive refractive power with its rear surface convex toward rear to make up an almost parallel light beam of the divergent light beam emerging from said third lens component, and a fifth lens component which fulfills the image forming function.
Claim 4
Dependent Claim
84 words
A zoom lens according to claim 2, wherein said fifth lens component comprises, from front to rear, a bi-convex lens V 1 whose front surface has a stronger curvature, a negative meniscus-shaped lens V 2 of forward concavity, a positive lens V 3 whose front surface has a stronger curvature, a negative meniscus-shaped lens V 4 of forward convexity, a bi-convex lens V 5 whose rear surface has a stronger curvature, and a positive lens V 6 whose front surface has a stronger curvature.
Claim 5
Dependent Claim
72 words
A zoom lens according to claim 3, satisfying the following conditions: 0.6<|R.sub.4,2 /F4|<0.8 (R.sub.4,2 <0) 1.3<|R.sub.5,1 /R.sub.5,3 |1.6 (R.sub.5,1 >0, R.sub.5,3 <0) 0.65<R.sub.5,8 /F.sub.5 <0.8 1.9<R.sub.5,9 /F.sub.5 <2.5 (R.sub.5,9 >0) 52<(ν.sub.5,1 +ν.sub.5,3)/2 wherein Ri,j is the radius of curvature of the j-th lens surface in the i-th component, νi,j is the Abbe number of the glass of the j-th lens element, and Fi is the focal length of the i-th lens component.
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) | 1991-09-13 | 1992-03-14 | 1992-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-13 | 1996-03-14 | 1996-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-13 | 2000-03-14 | 2000-09-13 | $7700.00 | Window Closed / Lapsed |