Patent US4609272A successfully refreshed from Google Patents.
US4609272A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Finder system of high image magnification
Assignee: Canon Inc
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Filing: 1985-06-28
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Granted: 1986-09-02
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Expires: 2005-06-28
Abstract
Abstract The disclosed finder system is constructed with three prisms. The first prism has a first entrance face, a first reflection face and a first exit face. The second prism has a second entrance face in contact with the first exit face, a second reflection face, and a second exit face. The third prism has a third entrance face in contact with the second exit face, a pair of roof-type reflection faces, a third reflection face in a common plane with the third entrance face, and a third exit face. Light entering through a photographic objective lens reflects from a quick return mirror to a focusing screen on which an image of an object forms. Light from the image reflects from the first reflection face to a direction parallel with an optical axis of the lens. The second reflection face then reflects the light progressively farther away from the optical axis to the pair of roof faces. The light then reflects progressively nearer the optical axis to the third reflection face, and then therefrom to an eyepiece for observing the finder image.
Inventors
- 👤 Hideo Yokota
- 👤 Masatake Kato
- 👤 Tetsuharu Nishimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:52
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/02; G03B19/12; G02; G02B; G02B5/00; G02B5/04
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
137 words
An optical apparatus for observing an object through an objective optical system, comprising: optical means having an entrance face for receiving a light beam from an objective lens, a first reflection face for reflecting the light beam received through said entrance face, a second reflection face inclined with respect to said entrance face to further reflect the light beam reflected by said first reflection face, a roof type third reflection face for reflecting the light beam reflected from said second reflection face, and a fourth reflection face for reflecting the light beam reflected from said third reflection face to an exit aperture, whereby the light beam is turned to a desired direction; and an eyepece lens for receiving the light beam passed through said exit aperture and for observing an object image from said objective optical system.
Claim 2
Dependent Claim
137 words
An optical apparatus for observing an object through an objective optical system, comprising: optical means having an entrance face for receiving a light beam from an objective lens, a first reflection face for reflecting the light beam received through said entrance face, a second reflection face inclined with respect to said entrance face to further reflect the light beam reflected by said first reflection face, a roof type third reflection face for reflecting the light beam reflected from said second reflection face, and a fourth reflection face for reflecting the light beam reflected from said third reflection face to an exit aperture, whereby the light beam is turned to a desired direction; and an eyepece lens for receiving the light beam passed through said exit aperture and for observing an object image from said objective optical system.
Claim 3
Dependent Claim
23 words
An optical apparatus according to claim 1, further comprising: a focusing screen arranged on an objective lens side of said first reflection face.
Claim 4
Dependent Claim
23 words
An optical apparatus according to claim 1, further comprising: a focusing screen arranged between said first reflection face and said second reflection face.
Claim 5
Dependent Claim
16 words
An optical apparatus according to claim 1, wherein said optical means includes a plurality of prisms.
Claim 6
Dependent Claim
38 words
An optical apparatus according to claim 1, wherein after reflection from said first reflection face, the axis of the light beam reflected by said second reflection face is substantially parallel with an optical axis of said eyepiece lens.
Claim 7
Dependent Claim
110 words
A finder comprising: (a) a first prism having an entrance face and first reflection means; (b) a second prism having second reflection means for reflecting a light path reflected by said first reflection means; (c) a third prism having third reflection means for reflecting a light path reflected by said second reflection means and fourth reflection means for reflecting a light path reflected by said third reflection means to an exit face; and (d) an eyepiece lens in a light path from said exit, whereby the light path connection said first reflection means and said second reflection means is substantially parallel with the light path passing through said eyepiece lens.
Claim 8
Dependent Claim
110 words
A finder comprising: (a) a first prism having an entrance face and first reflection means; (b) a second prism having second reflection means for reflecting a light path reflected by said first reflection means; (c) a third prism having third reflection means for reflecting a light path reflected by said second reflection means and fourth reflection means for reflecting a light path reflected by said third reflection means to an exit face; and (d) an eyepiece lens in a light path from said exit, whereby the light path connection said first reflection means and said second reflection means is substantially parallel with the light path passing through said eyepiece lens.
Claim 9
Dependent Claim
17 words
A finder according to claim 6, wherein said first, said second and said third prisms are unified.
Claim 10
Dependent Claim
17 words
A finder according to claim 7, further comprising: a focusing screen arranged adjacent to said first prism.
Claim 11
Dependent Claim
29 words
A finder according to claim 6, wherein said first prism and said second prism are spaced apart from each other, and said second and said third prisms are unified.
Claim 12
Dependent Claim
20 words
A finder according to claim 9, further comprising: a focusing screen arranged between said first prism and said second prism.
Claim 13
Dependent Claim
119 words
A camera apparatus comprising: (a) beam splitting means for splitting a first light path of an objective lens into second and third light paths; (b) image receiving means arranged on said second light path to receive an image of an object; (c) a prismatic optical arrangement positioned on said third light path and having first, second, third and fourth reflection faces for reflecting said third light path successively, whereby the object image is inverted laterally; and (d) an eyepiece lens arranged on the third light path emerging from said prismatic optical arrangement to observe the object image, whereby the light path connection said first reflection face with said second reflection face is substantially parallel with said first light path.
Claim 14
Dependent Claim
119 words
A camera apparatus comprising: (a) beam splitting means for splitting a first light path of an objective lens into second and third light paths; (b) image receiving means arranged on said second light path to receive an image of an object; (c) a prismatic optical arrangement positioned on said third light path and having first, second, third and fourth reflection faces for reflecting said third light path successively, whereby the object image is inverted laterally; and (d) an eyepiece lens arranged on the third light path emerging from said prismatic optical arrangement to observe the object image, whereby the light path connection said first reflection face with said second reflection face is substantially parallel with said first light path.
Claim 15
Dependent Claim
23 words
A camera apparatus according to claim 11, further comprising: a focusing screen between said light beam splitting means and said prismatic optical arrangement.
Claim 16
Dependent Claim
26 words
A camera apparatus according to claim 12, further comprising: a correction plate between said beam splitting means and said focusing screen to correct object image quality.
Claim 17
Dependent Claim
22 words
A camera apparatus according to claim 11, further comprising: a focusing screen between said first reflection face and said second reflection face.
Claim 18
Dependent Claim
23 words
A camera apparatus according to claim 11, further comprising: a low pass filter between said image receiving means and said beam splitting means.
Claim 19
Dependent Claim
20 words
A camera apparatus according to claim 15, wherein said image receiving means includes a semi-conductor solid state image pickup device.
References Cited (Backward Citations)
US3541919A
Cited
US4021823A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-09-01 | 1990-03-03 | 1990-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-01 | 1994-03-03 | 1994-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-01 | 1998-03-03 | 1998-09-02 | $7700.00 | Window Closed / Lapsed |