US5069536A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zoom lens system
Assignee: Olympus Corp
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Filing: 1989-05-30
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Granted: 1991-12-03
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Expires: 2009-05-30
Abstract
Abstract A zoom lens system comprising, in the order from the object side, a first lens unit having positive refractive power, a second lens unit having positive refractive power and a third lens unit having negative refractive power, and so adapted as to vary focal length from the wide position to the tele position by displacing the first lens unit integrally with the third lens unit toward the object side and displacing the second lens unit toward the object side at a speed slower than that of the first lens unit, said zoom lens system having such a composition as to permit simplifying structure of the driving mechanism for varying focal length, a compact design and favorable performance.
Inventors
- 👤 Yasuji Ogata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:28
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/143; G02B15/1431; G02B15/143103
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
152 words
A zoom lens system comprising: in the recited order from the object side, a first lens unit having positive refractive power, a second lens unit having positive refractive power and a third lens unit having negative refractive power, and means for varying focal length by displacing said first lens unit integrally with said third lens unit toward the object side and displacing said second lens unit toward the object side at a speed slower than that of said first lens unit, said zoom lens system satisfying the following conditions (1) through (3): 2.5<f.sub.1 /fw<6 (1) 0.6<f.sub.2 /fw<1 (2) 2<f.sub.1 /f.sub.3 /<7 (3) wherein the reference symbols f 1 , f 2 and f 3 represent focal lengths of the first lens unit, the second lens unit and the third lens unit respectively, and the reference symbol fw designates focal length of the zoom system as a whole at the wide position thereof.
Claim 2
Dependent Claim
152 words
A zoom lens system comprising: in the recited order from the object side, a first lens unit having positive refractive power, a second lens unit having positive refractive power and a third lens unit having negative refractive power, and means for varying focal length by displacing said first lens unit integrally with said third lens unit toward the object side and displacing said second lens unit toward the object side at a speed slower than that of said first lens unit, said zoom lens system satisfying the following conditions (1) through (3): 2.5<f.sub.1 /fw<6 (1) 0.6<f.sub.2 /fw<1 (2) 2<f.sub.1 /f.sub.3 /<7 (3) wherein the reference symbols f 1 , f 2 and f 3 represent focal lengths of the first lens unit, the second lens unit and the third lens unit respectively, and the reference symbol fw designates focal length of the zoom system as a whole at the wide position thereof.
Claim 3
Dependent Claim
91 words
A zoom lens system according to claim 1 wherein said first lens unit comprises a negative meniscus lens component convex on the object side and a positive meniscus lens component convex on the object side, said second lens unit consists of a negative lens component, a positive lens component, a stop, a positive lens component, a biconcave lens component and a positive lens component, and said third lens unit consists of a negative meniscus lens component convex on the image side and a meniscus lens component convex on the image side.
Claim 4
Dependent Claim
77 words
A zoom lens system according to claim 2 satisfying the following condition (4): 0<(r.sub.5 -r.sub.6)/(r.sub.5 +r.sub.6)<1 (4) wherein the reference symbol r 5 represents radius of curvature on the image side surface of the negative lens component arranged on the extremely object side in the second lens unit and the reference symbol r 6 designates radius of curvature on the object side surface of the positive lens component arranged on the image side of said negative lens.
Claim 5
Dependent Claim
30 words
A zoom lens system according to claim 3, wherein the object side surface of the biconcave lens component arranged in the second lens unit is designed as an aspherical surface.
Claim 6
Dependent Claim
47 words
A zoom lens system according to claim 3 wherein the object side surface of the positive lens component and the object side surface of the biconcave lens component arranged on the object side of the stop in the second lens unit are designed as aspherical surfaces respectively.
Claim 7
Dependent Claim
34 words
A zoom lens system according to claim 3 wherein the image side surface of the positive lens component arranged just after the stop in the second lens unit is designed as an aspherical surface.
Claim 8
Dependent Claim
36 words
A zoom lens system according to claim 1 wherein at least one surface in the second lens unit is an aspherical surface having negative power strengthened as the surface portions are farther from the optical axis.
References Cited (Backward Citations)
JPS57201213A
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JPS58184916A
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US4673258A
Cited
JPS6278522A
Cited
JPS6317422A
Cited
US4773744A
Cited
US4854682A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-02 | 1995-06-03 | 1995-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-02 | 1999-06-03 | 1999-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-02 | 2003-06-03 | 2003-12-03 | $7700.00 | Window Closed / Lapsed |