Patent US4852981A successfully refreshed from Google Patents.
US4852981A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Imaging lens system comprising a distributed index lens and a plano-convex lens
Assignee: Canon Inc
•
Filing: 1986-05-28
•
Granted: 1989-08-01
•
Expires: 2006-05-28
Abstract
Abstract An imaging lens system including a distributed index lens which has planar opposite end surfaces and in which the index gradient near the optic axis is substantially zero and the refractive index becomes progressively higher from the optic axis toward the marginal portion, and a plano-convex lens having a planar surface on the side thereof which is adjacent to the distributed index lens and formed of a homogeneous medium.
Inventors
- 👤 Shigeyuki Suda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:42
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/0087
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
68 words
An imaging lens system comprising a distributed index lens which has planar opposite end surfaces and in which the index gradient near the optic axis is substantially zero and the refractive index becomes progressively higher from the optic axis toward the marginal portion, and a plano-convex lens, having a planar surface on the side thereof which is adjacent to said distributed index lens, formed of a homogeneous medium.
Claim 2
Dependent Claim
68 words
An imaging lens system comprising a distributed index lens which has planar opposite end surfaces and in which the index gradient near the optic axis is substantially zero and the refractive index becomes progressively higher from the optic axis toward the marginal portion, and a plano-convex lens, having a planar surface on the side thereof which is adjacent to said distributed index lens, formed of a homogeneous medium.
Claim 3
Dependent Claim
58 words
An imaging lens system according to claim 1, which satisfies the following condition: ##EQU2## where d 1 is the lens thickness of said distributed index lens, d 2 and 4 are the on-axis thickness and the absolute value of the radius of curvature, respectively, of said plano-convex lens, and f is the focal length of the entire system.
Claim 4
Dependent Claim
28 words
An imaging lens system according to claim 1, wherein the planar surface of said distributed index lens and the planar surface of said plano-convex lens are joined together.
Claim 5
Dependent Claim
38 words
An imaging lens system according to claim 1, wherein the planar surface of said distibuted index lens and the planar surface of said plano-convex lens are opposed in parallelism to each other with an air space interposed therebetween.
Claim 6
Dependent Claim
93 words
A lens system comprising: a distributed index lens which has planar opposite end surfaces and in which there is an index gradient; and a plano-convex lens having a planar surface on a side thereof which is adjacent to said distributed index lens; wherein the following condition is satisfied: ##EQU3## where d 1 is the lens thickness of said distributed index lens, d 2 and r are the on-axis thickness and the absolute value of the radius of curvature, respectively, of said plano-convex lens, and f is the focal length of the entire system.
Claim 7
Dependent Claim
93 words
A lens system comprising: a distributed index lens which has planar opposite end surfaces and in which there is an index gradient; and a plano-convex lens having a planar surface on a side thereof which is adjacent to said distributed index lens; wherein the following condition is satisfied: ##EQU3## where d 1 is the lens thickness of said distributed index lens, d 2 and r are the on-axis thickness and the absolute value of the radius of curvature, respectively, of said plano-convex lens, and f is the focal length of the entire system.
Claim 8
Dependent Claim
27 words
A lens system according to claim 5, wherein the planar surface of said distributed index lens and the planar surface of said plano-convex lens are joined together.
Claim 9
Dependent Claim
15 words
A lens system according to claim 6, wherein the following condition is satisfied: d.sub.1 <d.sub.2.
Claim 10
Dependent Claim
38 words
A lens system according to claim 6, wherein said index gradient near the optical axis is substantially zero and the refractive index becomes progressively higher from the optical axis toward the marginal portion, in said distributed index lens.
Claim 11
Dependent Claim
17 words
A lens system according to claim 8, wherein said plano-convex lens is composed of a homogeneous medium.
Claim 12
Dependent Claim
87 words
A lens system comprising: a distributed index lens which has planar opposite end surfaces and in which there is an index gradient; and a plano-convex lens having a planar surface on the side thereof which is adjacent to said distributed index lens; wherein the absolute value of the radius of curvature of said plano-convex lens is substantially equal to d 1 /2+d 2 , where d 1 is the lens thickness of said distributed index lens and d 2 is the on-axis thickness of said plano-convex lens.
Claim 13
Dependent Claim
87 words
A lens system comprising: a distributed index lens which has planar opposite end surfaces and in which there is an index gradient; and a plano-convex lens having a planar surface on the side thereof which is adjacent to said distributed index lens; wherein the absolute value of the radius of curvature of said plano-convex lens is substantially equal to d 1 /2+d 2 , where d 1 is the lens thickness of said distributed index lens and d 2 is the on-axis thickness of said plano-convex lens.
References Cited (Backward Citations)
US3486808A
Cited
JPS58205122A
Cited
US4639094A
Cited
JPS59195611A
Cited
US4770506A
Cited
JPS60163015A
Cited
JPS60203909A
Cited
US4762403A
Cited
US4755039A
Cited
US4696552A
Cited
US4647159A
Cited
US4674843A
Cited
US4723843A
Cited
DE3626603A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-31 | 1993-01-30 | 1993-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-31 | 1997-01-30 | 1997-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-31 | 2001-01-30 | 2001-08-01 | $7700.00 | Window Closed / Lapsed |