Patent US5732245A successfully refreshed from Google Patents.
Patent US4653874A successfully refreshed from Google Patents.
US4653874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zoom lens
Assignee: Canon Inc
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Filing: 1986-06-26
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Granted: 1987-03-31
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Expires: 2006-06-26
Abstract
Abstract A zoom lens having at least three components, or, from front to rear, a first component of positive power, a second component of negative power and a third component with the air separations between the successive two of said three components being varied to effect zooming, whereby said first component is constructed with, from front to rear, a bi-convex first lens, a second lens of negative power and a third lens of positive power.
Inventors
- 👤 Sadatoshi Takahashi
- 👤 Toshiaki Asano
- 👤 Sadahiko Tsuji
- 👤 Kazuo Fujibayashi
- 👤 Masatake Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:20
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/14; G02B15/143; G02B15/1431; G02B15/143105
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
128 words
A zoom lens comprising: three lens groups, said three lens groups including, from front to rear, a first lens group of positive refractive power, a second lens group of negative refractive power and a third lens group, said first lens group consisting of, from front to rear, a bi-convex first lens, a second lens of negative refractive power, and a third lens of positive refractive power, whereby zooming is effected by changing the air separations between the first lens group and the second lens group and between the second lens group and the third lens group of said three lens groups, the three lenses of said first lens group being separated from each other and a first lens surface of said second lens being concave toward the object.
Claim 2
Dependent Claim
128 words
A zoom lens comprising: three lens groups, said three lens groups including, from front to rear, a first lens group of positive refractive power, a second lens group of negative refractive power and a third lens group, said first lens group consisting of, from front to rear, a bi-convex first lens, a second lens of negative refractive power, and a third lens of positive refractive power, whereby zooming is effected by changing the air separations between the first lens group and the second lens group and between the second lens group and the third lens group of said three lens groups, the three lenses of said first lens group being separated from each other and a first lens surface of said second lens being concave toward the object.
Claim 3
Dependent Claim
24 words
A zoom lens according to claim 1, satisfying the following conditions: 0.5f3<f1<2f3 0.8|R2|<R3|<1.5R2 wherein F1 is the focal length of said first lens groups;
Claim 4
Dependent Claim
34 words
f1, and f3 are the focal lengths of said first and said third lenses respectively; and Ri is the radius of curvature of the i-th surface counting from front in said first lens group.
Claim 5
Dependent Claim
34 words
f1, and f3 are the focal lengths of said first and said third lenses respectively; and Ri is the radius of curvature of the i-th surface counting from front in said first lens group.
Claim 6
Dependent Claim
15 words
A zoom lens according to claim 2, wherein said second lens is made of plastic.
Claim 7
Dependent Claim
24 words
A zoom lens according to claim 1, wherein said first lens is made of optical glass, and said third lens is made of plastic.
Claim 8
Dependent Claim
22 words
A zoom lens according to claim 1, wherein at least one of the lens surfaces in said first lens group is aspherical.
Claim 9
Dependent Claim
98 words
A zoom lens comprising: a front lens unit of positive power including: a first lens convex on both sides, a second negative lens with its first surface concave toward the object, and a third positive lens, the lenses of said front lens unit being separated from each other; a middle lens unit of negative power; a rear lens unit; wherein the zooming is performed by simultaneously changing the axial space between the front lens unit and the middle lens and the axial space between the middle lens unit and the rear lens unit; and satisfying the following conditions:
Claim 10
Dependent Claim
98 words
A zoom lens comprising: a front lens unit of positive power including: a first lens convex on both sides, a second negative lens with its first surface concave toward the object, and a third positive lens, the lenses of said front lens unit being separated from each other; a middle lens unit of negative power; a rear lens unit; wherein the zooming is performed by simultaneously changing the axial space between the front lens unit and the middle lens and the axial space between the middle lens unit and the rear lens unit; and satisfying the following conditions:
Claim 11
Dependent Claim
49 words
5f3<f1<2f3 0.8|R2|<|R3|<|1.5|R2.vertline. wherein f1 represents the focal length of said first lens, f3 represents the focal length of said third lens, R3 represents the curvature on the image side of the said first lens, and R2 represents the radius of curvature on the object side of said second lens.
Claim 12
Dependent Claim
49 words
5f3<f1<2f3 0.8|R2|<|R3|<|1.5|R2.vertline. wherein f1 represents the focal length of said first lens, f3 represents the focal length of said third lens, R3 represents the curvature on the image side of the said first lens, and R2 represents the radius of curvature on the object side of said second lens.
Claim 13
Dependent Claim
20 words
A zoom lens according to claim 6, in which said second lens and said third lens are made of plastics.
Claim 14
Dependent Claim
24 words
A zoom lens according to claim 7, in which one surface of said second lens and said third lens each have one aspherical surface.
Claim 15
Dependent Claim
129 words
A zoom lens comprising: a front lens unit of positive power consisting of a bi-convex first lens, a bi-concave second lens and third lens convex toward the object, the lenses of said front lens unit being separated from each other; a middle lens unit of negative power, and a rear lens unit, wherein zooming is performed by simultaneously changing the axial space between said front lens unit and said middle lens unit and the axial space between said middle lens unit and said rear lens unit, and said first lens is made of optical glass, said second and third lenses are made of plastic, and the radius of curvature on the image side of said second lens is larger than that on the object side of said third lens.
Claim 16
Dependent Claim
129 words
A zoom lens comprising: a front lens unit of positive power consisting of a bi-convex first lens, a bi-concave second lens and third lens convex toward the object, the lenses of said front lens unit being separated from each other; a middle lens unit of negative power, and a rear lens unit, wherein zooming is performed by simultaneously changing the axial space between said front lens unit and said middle lens unit and the axial space between said middle lens unit and said rear lens unit, and said first lens is made of optical glass, said second and third lenses are made of plastic, and the radius of curvature on the image side of said second lens is larger than that on the object side of said third lens.
Claim 17
Dependent Claim
62 words
A zoom lens according to claim 9, which satisfies the following conditions: 0.5f3<f1<2f3 0.8|R2|<|R3|<1.5|R2| wherein f1 represents the focal length of said first lens, f3 represents the focal length of said third lens, R2 represents the radius of curvature on the image side of said first lens and R3 represents the radius of curvature on the object side of said second lens.
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) | 1990-03-30 | 1990-09-29 | 1991-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-30 | 1994-09-29 | 1995-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-30 | 1998-09-29 | 1999-03-31 | $7700.00 | Window Closed / Lapsed |