Patent FR691187A successfully refreshed from Google Patents.
Patent US5659427A successfully refreshed from Google Patents.
US5659427A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diopter movement type of finder optical system for single-lens reflex cameras
Assignee: Olympus Corp
•
Filing: 1995-04-21
•
Granted: 1997-08-19
•
Expires: 2015-04-21
Abstract
Abstract The invention is directed to a diopter movement type of finder optical system for single-lens reflex cameras, which is well corrected in terms of various aberrations such as spherical aberration and off-axis aberrations, is of resolution so high that the image can be well viewed, and has a short overall length or is compact. This finder optical system comprises, in order from the side of the eye point EP, a first lens 2 having positive refracting power, a second lens 3 having positive refracting power, a third lens 4 having negative refracting power and a pentaprism 5, with the first and second lenses 2 and 3 being moved together in the optical axis direction for diopter movement while the third lens 4 remains fixed. Moreover, the finder optical system conforms to four conditions regarding the focal lengths of the first to third lenses and the composite focal length of the first and second lenses 2 and 3.
Inventors
- 👤 Noriyuki Iyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:18
CPC Classifications
G; G03; G03B; G03B13/00; G03B13/02; G03B13/06; G02; G02B; G02B23/00; G02B23/14; G02B23/145
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
90 words
A diopter movement type of finder optical system for single-lens reflex cameras, comprising, in order from an eye point side: a first lens having positive refracting power; a second lens having positive refracting power; a third lens having negative refracting power; and an optical unit including a plurality of reflecting surfaces having an image-inverting action; said first lens and said second lens being moved together in an optical axis direction for diopter movement while said third lens remains fixed; and said finder optical system conforming to the following condition (1):
Claim 2
Dependent Claim
90 words
A diopter movement type of finder optical system for single-lens reflex cameras, comprising, in order from an eye point side: a first lens having positive refracting power; a second lens having positive refracting power; a third lens having negative refracting power; and an optical unit including a plurality of reflecting surfaces having an image-inverting action; said first lens and said second lens being moved together in an optical axis direction for diopter movement while said third lens remains fixed; and said finder optical system conforming to the following condition (1):
Claim 3
Dependent Claim
43 words
35<f 12 /f A <0.5 (1) wherein f 12 is a composite focal length of said first lens and said second lens, and f A is an overall focal length of said finder optical system in a reference state (0 m -1 ).
Claim 4
Dependent Claim
43 words
35<f 12 /f A <0.5 (1) wherein f 12 is a composite focal length of said first lens and said second lens, and f A is an overall focal length of said finder optical system in a reference state (0 m -1 ).
Claim 5
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 1, which further conforms to the following condition (2): 0.55<f.sub.1 /f.sub.A <0.95 (2) wherein f 1 is a focal length of said first lens.
Claim 6
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 1, which further conforms to the following condition (3): 0.7<f.sub.2 /f.sub.A <1.3 (3) wherein f 2 is a focal length of said second lens.
Claim 7
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 1, which further conforms to the following condition (4): 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 3 is a focal length of said third lens.
Claim 8
Dependent Claim
56 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 1, which further conforms to the following conditions (2) and (3): 0.55<f.sub.1 /f.sub.A <0.95 (2) 0.7<f.sub.2 /f.sub.A <1.3 (3) wherein f 1 is a focal length of said first lens and f 2 is a focal length of said second lens.
Claim 9
Dependent Claim
56 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 1, which further conforms to the following conditions (3) and (4): 0.7<f.sub.2 /f.sub.A <1.3 (3) 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 2 is a focal length of said second lens and f 3 is a focal length of said third lens.
Claim 10
Dependent Claim
55 words
The diopter movement type of finder optical system for single-lens reflex cameras according to 1, which further conforms to the following conditions (2) and (4): 0.55<f.sub.1 /f.sub.A <0.95 (2) 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 1 is a focal length of said first lens and f 3 is a focal length of said third lens.
Claim 11
Dependent Claim
55 words
The diopter movement type of finder optical system for single-lens reflex cameras according to 1, which further conforms to the following conditions (2) and (4): 0.55<f.sub.1 /f.sub.A <0.95 (2) 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 1 is a focal length of said first lens and f 3 is a focal length of said third lens.
Claim 12
Dependent Claim
71 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 1, which further conforms to the following conditions (2), (3) and (4): 0.55<f.sub.1 /f.sub.A <0.95 (2) 0.7<f.sub.2 /f.sub.A <1.3 (3) 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 1 is a focal length of said first lens, f 2 is a focal length of said second lens, and f 3 is a focal length of said third lens.
Claim 13
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to any one of claims 1, 2, 3, 4, 5, 6, 7, or 8, which further conforms to the following condition (1)': 0.375<f.sub.12 /f.sub.A <0.45 (1)'.
Claim 14
Dependent Claim
126 words
A diopter movement type of finder optical system for single-lens reflex cameras, comprising, in order from an eye point side: a first lens having positive refracting power; a second lens having positive refracting power; a third lens having negative refracting power; and an optical unit including a plurality of reflecting surfaces having an image-inverting action; said first lens and said second lens being moved together in an optical axis direction for diopter movement while said third lens remains fixed; and said finder optical system conforming to the following condition (2): 0.55<f.sub.1 /f.sub.A <0.95 (2) wherein f 1 is a focal length of said first lens, and f A is an overall focal length of said finder optical system in a reference state (0 m -1 ).
Claim 15
Dependent Claim
126 words
A diopter movement type of finder optical system for single-lens reflex cameras, comprising, in order from an eye point side: a first lens having positive refracting power; a second lens having positive refracting power; a third lens having negative refracting power; and an optical unit including a plurality of reflecting surfaces having an image-inverting action; said first lens and said second lens being moved together in an optical axis direction for diopter movement while said third lens remains fixed; and said finder optical system conforming to the following condition (2): 0.55<f.sub.1 /f.sub.A <0.95 (2) wherein f 1 is a focal length of said first lens, and f A is an overall focal length of said finder optical system in a reference state (0 m -1 ).
Claim 16
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 10, which further conforms to the following condition (3): 0.7<f.sub.2 /f.sub.A <1.3 (3) wherein f 2 is a focal length of said second lens.
Claim 17
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 10, which further conforms to the following condition (4): 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 3 is a focal length of said third lens.
Claim 18
Dependent Claim
56 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 10, which further conforms to the following conditions (3) and (4): 0.7<f.sub.2 /f.sub.A <1.3 (3) 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 2 is a focal length of said second lens and f 3 is a focal length of said third lens.
Claim 19
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to any one of claims 10, 2, 5, 7, 8, 11, 12 or 13, which further conforms to the following condition (2)': 0.55<f.sub.1 /f.sub.A <0.85 (2)'.
Claim 20
Dependent Claim
126 words
A diopter movement type of finder optical system for single-lens reflex cameras, comprising, in order from an eye point side: a first lens having positive refracting power; a second lens having positive refracting power; a third lens having negative refracting power; and an optical unit including a plurality of reflecting surfaces having an image-inverting action; said first lens and said second lens being moved together in an optical axis direction for diopter movement while said third lens remains fixed; and said finder optical system conforming to the following condition (3): 0.7<f.sub.2 /f.sub.A <1.3 (3) wherein f 2 is a focal length of said second lens, and f A is an overall focal length of said finder optical system in a reference state (0 m -1 ).
Claim 21
Dependent Claim
126 words
A diopter movement type of finder optical system for single-lens reflex cameras, comprising, in order from an eye point side: a first lens having positive refracting power; a second lens having positive refracting power; a third lens having negative refracting power; and an optical unit including a plurality of reflecting surfaces having an image-inverting action; said first lens and said second lens being moved together in an optical axis direction for diopter movement while said third lens remains fixed; and said finder optical system conforming to the following condition (3): 0.7<f.sub.2 /f.sub.A <1.3 (3) wherein f 2 is a focal length of said second lens, and f A is an overall focal length of said finder optical system in a reference state (0 m -1 ).
Claim 22
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 15, which further conforms to the following condition (4): 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 3 is a focal length of said third lens.
Claim 23
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to any one of claims 15, 3, 5, 6, 8, 11, 13 or 16, which further conforms to the following condition (3)': 0.75<f.sub.2 /f.sub.A <1.25 (3)'.
Claim 24
Dependent Claim
126 words
A diopter movement type of finder optical system for single-lens reflex cameras, comprising, in order from an eye point side: a first lens having positive refracting power; a second lens having positive refracting power; a third lens having negative refracting power; and an optical unit including a plurality of reflecting surfaces having an image-inverting action; said first lens and said second lens being moved together in an optical axis direction for diopter movement while said third lens remains fixed; and said finder optical system conforming to the following condition (4): 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 3 is a focal length of said third lens, and f A is an overall focal length of said finder optical system in a reference state (0 m -1 ).
Claim 25
Dependent Claim
126 words
A diopter movement type of finder optical system for single-lens reflex cameras, comprising, in order from an eye point side: a first lens having positive refracting power; a second lens having positive refracting power; a third lens having negative refracting power; and an optical unit including a plurality of reflecting surfaces having an image-inverting action; said first lens and said second lens being moved together in an optical axis direction for diopter movement while said third lens remains fixed; and said finder optical system conforming to the following condition (4): 0.5<|f.sub.3 |/f.sub.A <0.75 (4) wherein f 3 is a focal length of said third lens, and f A is an overall focal length of said finder optical system in a reference state (0 m -1 ).
Claim 26
Dependent Claim
81 words
The diopter movement type of finder optical system for single-lens reflex cameras according to any one of claims 1-8, 10-15 and 18, which further conforms to the following condition (5): 0.4<SF1<0.9 (5) wherein SF1 is a shape factor defined by SF=(RE+RS)/(RE-RS) where RE is a radius of curvature of a surface of a first lens located on said eye point side, and RS is a radius of curvature of a surface of a first lens located on a finder screen side.
Claim 27
Dependent Claim
81 words
The diopter movement type of finder optical system for single-lens reflex cameras according to any one of claims 1-8, 10-15 and 18, which further conforms to the following condition (6): -0.7<SF2<0.6 (6) wherein SF2 is a shape factor defined by SF=(RE+RS)/(RE-RS) where RE is a radius of curvature of a surface of a second lens located on said eye point side, and RS is a radius of curvature of a surface of a second lens located on a finder screen side.
Claim 28
Dependent Claim
81 words
The diopter movement type of finder optical system for single-lens reflex cameras according to any one of claims 1-8, 10-15 and 18, which further conforms to the following condition (7): -0.8<SF3<0.8 (7) wherein SF3 is a shape factor defined by SF=(RE+RS)/(RE-RS) where RE is a radius of curvature of a surface of a third lens located on said eye point side, and RS is a radius of curvature of a surface of a third lens located on a finder screen side.
Claim 29
Dependent Claim
39 words
The diopter movement type of finder optical system for single-lens reflex cameras according to any one of claims 18, 4, 6, 7, 8, 12, 13, or 16, which further conforms to the following condition (4)': 0.5<|f.sub.3 |/f.sub.A <0.7 (4)'.
Claim 30
Dependent Claim
26 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 19, which further conforms to the following condition (5)': 0.5<SF1<0.85 (5)'.
Claim 31
Dependent Claim
26 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 20, which further conforms to the following condition (6)': -0.66<SF2<0.6 (6)'.
Claim 32
Dependent Claim
26 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 21, which further conforms to the following condition (7)': -0.6<SF3<0.4 (7)'.
Claim 33
Dependent Claim
78 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 19, which further conforms to the following condition (6): -0.7<SF2<0.6 (6) wherein SF2 is the shape factor defined by SF=(RE+RS)/(RE-RS) where RE is the radius of curvature of the surface of the second lens located on the side of the eye point EP, and RS is the radius of curvature of the surface of the second lens located on the finder screen side.
Claim 34
Dependent Claim
78 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 19, which further conforms to the following condition (7): -0.8<SF3<0.8 (7) wherein SF3 is the shape factor defined by SF=(RE+RS)/(RE-RS) where RE is the radius of curvature of the surface of the third lens located on the side of the eye point EP, and RS is the radius of curvature of the surface of the third lens located on the finder screen side.
Claim 35
Dependent Claim
78 words
The diopter movement type of finder optical system for single-lens reflex cameras according to claim 20, which further conforms to the following condition (7): -0.8<SF3<0.8 (7) wherein SF3 is the shape factor defined by SF=(RE+RS)/(RE-RS) where RE is the radius of curvature of the surface of the third lens located on the side of the eye point EP, and RS is the radius of curvature of the surface of the third lens located on the finder screen side.
References Cited (Backward Citations)
JPS54126530A
Cited
US4664485A
Cited
JPS6048730A
Cited
JPS6119969A
Cited
US4812023A
Cited
US4854680A
Cited
JPH05181071A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-08-18 | 2001-02-17 | 2001-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-18 | 2005-02-17 | 2005-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-18 | 2009-02-17 | 2009-08-19 | $7700.00 | Window Closed / Lapsed |