Patent US1211748A successfully refreshed from Google Patents.
Patent US5184252A successfully refreshed from Google Patents.
US5184252A
Expired / Lapsed
US
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Finder optical system
Assignee: Olympus Corp
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Filing: 1991-04-04
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Granted: 1993-02-02
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Expires: 2011-04-04
Abstract
Abstract A finder optical system including an objective having a positive refractive power, an image erecting optical member for erecting an image formed by the objective, and an eyepiece for allowing observation of the image formed by the objective and erected by the image erecting optical member. The objective consists of a first positive lens component and a second negative lens component, or a single lens having a convex surface on the object side. This finder optical system has a simple composition, a compact external design and a relatively wide field angle.
Inventors
- 👤 Yuji Miyauchi
- 👤 Shinichi Yoshii
- 👤 Tatsuru Kanamori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:01
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/18; G02B23/00; G02B23/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
94 words
A finder optical system comprising: an objective including a first positive lens component and a second negative lens component, an image erecting optical system for erecting an image formed by said objective, and an eyepiece for allowing observation of the image formed by said objective and erected by said image erecting optical system; said finder optical system satisfying the following condition: 0.03<|f.sub.p /f.sub.n |<0.4 wherein the reference symbol f p represents the focal length of said first lens component and the reference symbol f n designates the focal length of said second lens component.
Claim 2
Dependent Claim
94 words
A finder optical system comprising: an objective including a first positive lens component and a second negative lens component, an image erecting optical system for erecting an image formed by said objective, and an eyepiece for allowing observation of the image formed by said objective and erected by said image erecting optical system; said finder optical system satisfying the following condition: 0.03<|f.sub.p /f.sub.n |<0.4 wherein the reference symbol f p represents the focal length of said first lens component and the reference symbol f n designates the focal length of said second lens component.
Claim 3
Dependent Claim
55 words
A finder optical system comprising an objective consisting of a single positive lens having a convex surface on the object side, an image erecting optical system for erecting an image formed by said objective, and an eyepiece for allowing observation of the image formed by said objective and erected by said image erecting optical system.
Claim 4
Dependent Claim
55 words
A finder optical system comprising an objective consisting of a single positive lens having a convex surface on the object side, an image erecting optical system for erecting an image formed by said objective, and an eyepiece for allowing observation of the image formed by said objective and erected by said image erecting optical system.
Claim 5
Dependent Claim
77 words
A finder optical system according to claim 2 satisfying the following conditions: |r.sub.asp /r.sub.sp |<1 0.04<1/f.sub.o <0.2 wherein the reference symbol r asp represents the paraxial radius of curvature on an aspherical surface which is one of the surfaces of said objective, the reference symbol r sp designates the radius of curvature on a spherical surface which is the other surface of said objective and the reference symbol f o denotes the focal length of said objective.
Claim 6
Dependent Claim
43 words
A finder optical system according to claim 3 satisfying the following condition: |r.sub.2 /r.sub.1 |<1 wherein the reference symbols r 1 and r 2 represent the radii of curvature on the object side surface and the image said surface respectively of said objective.
References Cited (Backward Citations)
JPS6330812A
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JPS6344616A
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JPS6344617A
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US4751539A
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JPH01154114A
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JPH01255825A
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US4926201A
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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) | 1996-02-02 | 1996-08-03 | 1997-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-02 | 2000-08-03 | 2001-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-02 | 2004-08-03 | 2005-02-02 | $7700.00 | Window Closed / Lapsed |