US4441792A
Expired / Lapsed
US
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Telecentric projection lenses
Assignee: Canon Inc
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Filing: 1981-02-26
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Granted: 1984-04-10
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Expires: 2001-02-26
Abstract
Abstract Telecentric projection lenses are disclosed which are precise in terms of their F number and which have a high resolving power and high contrast, namely well corrected spherical aberration, coma, curvature of field and distortion, and are intended for use at aperture efficiency of 100% and at magnification of about 1/10. The telecentric projection lens comprises a first lens group consisting of a positive single lens, a second lens group consisting of a negative single lens and a third lens group consisting of two positive lenses, arranged in this order as viewed from the object field side. The lens of the second group is a double concave lens and one of the positive lenses in the third group has a cemented surface whose center of curvature lies on the side of object field. The focal lengths f 1 , f 2 and f 3 of the first, second and third groups and the focal length f of the whole lens system satisfy the following conditions: 1.69≦|f.sub.1 /f.sub.2 |≦2.55 -0.33≦f.sub.2 /f≦-0.19 0.41≦f.sub.3 /f≦0.59.
Inventors
- 👤 Masamichi Tateoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:01
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/22
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
124 words
A telecentric projection lens comprising: a first lens component composed of a single lens of positive refractive power; a second lens component composed of a bi-concave lens of negative refractive power; and a third lens component including at least two positive lenses one having a cemented surface whose center of curvature is spaced from the surface towards the object field side, said first, second and thrid lens components being arranged in the recited order as viewed from the object field side and satisfying the conditions: 1.69≦|f.sub.1 /f.sub.2 |≦2.55 -0.33≦f.sub.2 /f≦-0.19 0.41≦f.sub.3 /f≦0.59 wherein f 1 , f 2 and f 3 are focal lengths of said first, second and third lens components, respectively, and f is the focal length of the whole lens system.
Claim 2
Dependent Claim
124 words
A telecentric projection lens comprising: a first lens component composed of a single lens of positive refractive power; a second lens component composed of a bi-concave lens of negative refractive power; and a third lens component including at least two positive lenses one having a cemented surface whose center of curvature is spaced from the surface towards the object field side, said first, second and thrid lens components being arranged in the recited order as viewed from the object field side and satisfying the conditions: 1.69≦|f.sub.1 /f.sub.2 |≦2.55 -0.33≦f.sub.2 /f≦-0.19 0.41≦f.sub.3 /f≦0.59 wherein f 1 , f 2 and f 3 are focal lengths of said first, second and third lens components, respectively, and f is the focal length of the whole lens system.
Claim 3
Dependent Claim
56 words
A telecentric projection lens as set forth in claim 1, wherein the surface of the object field side of the lens of said first lens component is convex toward the object field side, and wherein the two positive lenses of said third lens component are spaced apart to form an air lens element which is bi-concave.
Claim 4
Dependent Claim
109 words
A telecentric projection lens comprising: a first lens component composed of a single lens of positive refractive power; a second lens component composed of a bi-concave lens of negative refractive power; and a third lens component composed of three lenses one having a cemented surface, said first, second and third lens components being arranged in the recited order as viewed from the object field side and satisfying the following conditions: 1.72≦|f.sub.1 /f.sub.2 |≦2.58 -0.33≦f.sub.2 /f≦-0.19 0.41≦f.sub.3 /f≦0.59 wherein, f 1 , f 2 and f 3 are focal lengths of said first, second and third lens components, respectively, and f is the focal length of the whole lens system.
Claim 5
Dependent Claim
109 words
A telecentric projection lens comprising: a first lens component composed of a single lens of positive refractive power; a second lens component composed of a bi-concave lens of negative refractive power; and a third lens component composed of three lenses one having a cemented surface, said first, second and third lens components being arranged in the recited order as viewed from the object field side and satisfying the following conditions: 1.72≦|f.sub.1 /f.sub.2 |≦2.58 -0.33≦f.sub.2 /f≦-0.19 0.41≦f.sub.3 /f≦0.59 wherein, f 1 , f 2 and f 3 are focal lengths of said first, second and third lens components, respectively, and f is the focal length of the whole lens system.
Claim 6
Dependent Claim
34 words
A telecentric projection lens as set forth in claim 3, wherein the nearest surface to the object field side of the lens of said first lens component is convexed toward the object field side.
Claim 7
Dependent Claim
62 words
A telecentric projection lens as set forth in claim 4, wherein the nearest lens of said third lens component to the object field side is a meniscus lens whose concave surface faces the object field side and the nearest lens of said tnird lens component to the image field side is a meniscus lens whose concave surface faces the image field side.
Claim 8
Dependent Claim
109 words
A telecentric projection lens comprising: a first lens component composed of a single lens of positive refractive power: a second lens component composed of a bi-concave lens of negative refractive power; and a third lens component composed of four lenses one having a cemented surface, said first, second and third lens components being arranged in the recited order as viewed from the object field side and satisfying the following conditions: 1.72≦|f.sub.1 /f.sub.2 |≦2.58 -0.33≦f.sub.2 /f≦0.19 0.41≦f.sub.3 /f≦0.59 wherein, f 1 , f 2 and f 3 are focal lengths of said first, second and third lens components, respectively, and f is the focal length of the whole lens system.
Claim 9
Dependent Claim
109 words
A telecentric projection lens comprising: a first lens component composed of a single lens of positive refractive power: a second lens component composed of a bi-concave lens of negative refractive power; and a third lens component composed of four lenses one having a cemented surface, said first, second and third lens components being arranged in the recited order as viewed from the object field side and satisfying the following conditions: 1.72≦|f.sub.1 /f.sub.2 |≦2.58 -0.33≦f.sub.2 /f≦0.19 0.41≦f.sub.3 /f≦0.59 wherein, f 1 , f 2 and f 3 are focal lengths of said first, second and third lens components, respectively, and f is the focal length of the whole lens system.
Claim 10
Dependent Claim
32 words
A telecentric projection lens set forth in claim 6, wherein the nearest surface to the object field side of the lens of said first lens component is convexed toward the object side.
Claim 11
Dependent Claim
64 words
A telecentric projection lens as set forth in claim 7, wherein the nearest lens of said third lens component to the object field side is a meniscus lens element whose concave surface faces the object field side and the nearest lens of said third lens component to the image field side is a meniscus lens element whose concave surface faces the image field side.
References Cited (Backward Citations)
US2685229A
Cited
US4093348A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-10 | 1987-10-10 | 1988-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-10 | 1991-10-10 | 1992-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-10 | 1995-10-10 | 1996-04-10 | $7700.00 | Window Closed / Lapsed |