Patent US4790638A successfully refreshed from Google Patents.
US4790638A
Expired / Lapsed
US
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Lens system for projecting images of microfilm
Assignee: Minolta Co Ltd
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Filing: 1986-09-29
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Granted: 1988-12-13
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Expires: 2006-09-29
Abstract
Abstract There is disclosed a lens system for projecting images of microfilm onto a screen or the like. The lens system is characterized by five lens components, that is, a first positive meniscus lens component convex to the magnification side, a second negative meniscus lens component concave to the magnification side, a third biconvex lens component, a fourth biconcave lens component having a powerful concave surface faced to the magnification side, and a fifth biconvex lens component.
Inventors
- 👤 Satoshi Iwasaki
- 👤 Toshihiko Ueda
- 👤 Kunihiko Konoma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:05
CPC Classifications
G; G02; G02B; G02B9/00; G02B9/60; G02B13/00; G02B13/24
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
99 words
A lens system for projecting images of microfilm comprising from the magnification side to the reduction side, a first lens component of a positive meniscus lens component convex to the magnification side, a second lens component of a negative meniscus lens component concave to the magnification side, a third lens component of a biconvex lens component, a fourth lens component of a biconcave lens component having a powerful concave surface faced to the magnification side, and a fifth lens component of a biconvex lens component, wherein said lens components are respectively spaced from each other on an optical axis.
Claim 2
Dependent Claim
99 words
A lens system for projecting images of microfilm comprising from the magnification side to the reduction side, a first lens component of a positive meniscus lens component convex to the magnification side, a second lens component of a negative meniscus lens component concave to the magnification side, a third lens component of a biconvex lens component, a fourth lens component of a biconcave lens component having a powerful concave surface faced to the magnification side, and a fifth lens component of a biconvex lens component, wherein said lens components are respectively spaced from each other on an optical axis.
Claim 3
Dependent Claim
63 words
A lens system as claimed in claim 1 further fulfilling following conditions: 0.9≦TL/f≦1.1 0.6≦εd/f≦0.7 wherein, f represents a total focal length, εd represents a length of an optical axis from the frontmost lens surface to the rearmost lens surface of the lens system, and TL represents the sum of εd described above with a lens back focal length at an infinite focussing condition.
Claim 4
Dependent Claim
59 words
A lens system as claimed in claim 1 further fulfilling following conditions: ##EQU3## wherein, f represents a total focal length, f 1 and f 4 represent focal lengths of first and fourth lens components respectively, and ν 1 , ν 2 , ν 3 and ν 4 represent the Abbe numbers of the first through fourth lens components respectively.
Claim 5
Dependent Claim
26 words
A lens system as claimed in claim 1 further comprising an aperture stop positioned at a position on the forward side of the third lens component.
Claim 6
Dependent Claim
22 words
A lens system as claimed in claim 1 further comprising an aperture stop positioned at the frontmost side of the lens system.
Claim 7
Dependent Claim
92 words
A lens system for projecting images of microfilm comprising from the magnification side to the reduction side, a first lens component of a positive meniscus lens component convex to the magnification side, a second lens component of a negative meniscus lens component concave to the magnification side, a third lens component of a biconvex lens component, a fourth lens component of a biconcave lens element having a powerful concave surface faced to the magnification side, and a fifth lens component of a biconvex lens component, wherein the lens system fulfills following conditions:
Claim 8
Dependent Claim
92 words
A lens system for projecting images of microfilm comprising from the magnification side to the reduction side, a first lens component of a positive meniscus lens component convex to the magnification side, a second lens component of a negative meniscus lens component concave to the magnification side, a third lens component of a biconvex lens component, a fourth lens component of a biconcave lens element having a powerful concave surface faced to the magnification side, and a fifth lens component of a biconvex lens component, wherein the lens system fulfills following conditions:
Claim 9
Dependent Claim
51 words
9≦TL/f≦1.1 0.6≦εd/f≦0.7 wherein f represents a total focal length, εd represents a length of an optical axis from the frontmost lens surface to the rearmost lens surface of the lens system, and TL represents the sum of εd described above with a lens back focal length at an infinite focussing condition.
Claim 10
Dependent Claim
51 words
9≦TL/f≦1.1 0.6≦εd/f≦0.7 wherein f represents a total focal length, εd represents a length of an optical axis from the frontmost lens surface to the rearmost lens surface of the lens system, and TL represents the sum of εd described above with a lens back focal length at an infinite focussing condition.
Claim 11
Dependent Claim
53 words
A lens system as claimed in claim 6 further fulfilling following conditions: ##EQU4## wherein, f 1 and f 4 represent focal lengths of first and fourth lens components respectively, and ν 1 , ν 2 , ν 3 and ν 4 represent the Abbe numbers of the first through fourth lens components respectively.
Claim 12
Dependent Claim
26 words
A lens system as claimed in claim 6 further comprising an aperture stop positioned at a position on the forward side of the third lens component.
Claim 13
Dependent Claim
22 words
A lens system as claimed in claim 6, further comprising an aperture stop positioned at the frontmost side of the lens system.
Claim 14
Dependent Claim
140 words
A lens system for projecting images of microfilm comprising from the magnification side to the reduction side: a first lens component of a positive meniscus lens component convex to the magnification side; a second lens component of a negative meniscus lens component concave to the magnification side; a third lens component of a biconvex lens component; a fourth lens component of a biconcave lens element having a powerful concave surface faced to the magnification side, and a fifth lens component of a biconvex lens component; wherein the lens system fulfills the following conditions: ##EQU5## wherein, f represents a total focal length, f 1 and f 4 represent focal lengths of first and fourth lens components, respectively, and ν 1 , ν 2 , ν 3 and ν 4 represent the Abbe numbers of the first through fourth lens components, respectively.
Claim 15
Dependent Claim
140 words
A lens system for projecting images of microfilm comprising from the magnification side to the reduction side: a first lens component of a positive meniscus lens component convex to the magnification side; a second lens component of a negative meniscus lens component concave to the magnification side; a third lens component of a biconvex lens component; a fourth lens component of a biconcave lens element having a powerful concave surface faced to the magnification side, and a fifth lens component of a biconvex lens component; wherein the lens system fulfills the following conditions: ##EQU5## wherein, f represents a total focal length, f 1 and f 4 represent focal lengths of first and fourth lens components, respectively, and ν 1 , ν 2 , ν 3 and ν 4 represent the Abbe numbers of the first through fourth lens components, respectively.
Claim 16
Dependent Claim
26 words
A lens system as claimed in claim 10 further comprising an aperture stop positioned at a position on the forward side of the third lens component.
Claim 17
Dependent Claim
22 words
A lens system as claimed in claim 10 further comprising an aperture stop positioned at the frontmost side of the lens system.
Claim 18
Dependent Claim
86 words
A lens system for projecting images of microfilm consisting of from the magnification side to the reduction side: a first lens component of a positive meniscus lens component convex to the magnification side; a second lens component of a negative meniscus lens component concave to the magnification side; a third lens component of a biconvex lens component; a fourth lens component of a biconcave lens component having a powerful concave surface faced to the magnification side, and a fifth lens component of a biconvex lens component.
Claim 19
Dependent Claim
86 words
A lens system for projecting images of microfilm consisting of from the magnification side to the reduction side: a first lens component of a positive meniscus lens component convex to the magnification side; a second lens component of a negative meniscus lens component concave to the magnification side; a third lens component of a biconvex lens component; a fourth lens component of a biconcave lens component having a powerful concave surface faced to the magnification side, and a fifth lens component of a biconvex lens component.
Claim 20
Dependent Claim
62 words
A lens system as claimed in claim 13 further fulfilling the following conditions: 0.9≦TL/f≦1.1 0.6≦εd/f≦0.7 wherein, f represents a total focal length, εd represents a length of an optical axis from the frontmost lens surface to the rearmost lens surface of the lens system, and TL represents the sum of εd described above and a lens positioned at an infinite focusing condition.
Claim 21
Dependent Claim
60 words
A lens system as claimed in claim 13 further fulfilling the following conditions: ##EQU6## wherein, f represents a total focal length, f 1 and f 4 represent focal lengths of first and fourth lens components, respectively, and ν 1 , ν 2 , ν 3 and ν 4 represent the Abbe numbers of the first through fourth lens components, respectively.
Claim 22
Dependent Claim
26 words
A lens system as claimed in claim 13 further comprising an aperture stop positioned at a position on the forward side of the third lens component.
Claim 23
Dependent Claim
22 words
A lens system as claimed in claim 13 further comprising an aperture stop position at the frontmost side of the lens system.
References Cited (Backward Citations)
US3698796A
Cited
US3907418A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-13 | 1992-06-13 | 1992-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-13 | 1996-06-13 | 1996-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-13 | 2000-06-13 | 2000-12-13 | $7700.00 | Window Closed / Lapsed |