Patent US3971052A successfully refreshed from Google Patents.
US3971052A
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US
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Compact galilean viewfinder
Assignee: Polaroid Corp
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Filing: 1975-04-21
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Granted: 1976-07-20
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Expires: 1995-04-21
Abstract
Abstract A compact Galilean viewfinder, having an objective comprising a plano-convex negative de-centered front element, with its optical axis below the central axis of the finder, and an eye lens comprising a plano-convex rear element of positive power that is de-centered with its optical axis below the central axis of the finder, in which the eye lens is tilted to reduce astigmatism and bent to reduce coma.
Inventors
- 👤 William T. Plummer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:54
CPC Classifications
G; G03; G03B; G03B13/00; G03B13/02; G03B13/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
35 words
In a Galilean finder, a negative de-centered objective lens and a positive de-centered eye lens, said lenses being de-centered in the same sense to cause refractions in opposite senses of parallel rays entering said finder.
Claim 2
Dependent Claim
35 words
In a Galilean finder, a negative de-centered objective lens and a positive de-centered eye lens, said lenses being de-centered in the same sense to cause refractions in opposite senses of parallel rays entering said finder.
Claim 3
Dependent Claim
76 words
A reversed Galilean finder, comprising a plano-concave objective lens element having an optical axis displaced from its geometrical center, a plano-convex eye lens element having an optical axis displaced from its geometrical center, and means for mounting said elements in spaced relationship with the concave side of said objective lens element confronting the convex side of said eye lens element with said optical axis displaced in the same sense from a line joining said geometrical centers.
Claim 4
Dependent Claim
76 words
A reversed Galilean finder, comprising a plano-concave objective lens element having an optical axis displaced from its geometrical center, a plano-convex eye lens element having an optical axis displaced from its geometrical center, and means for mounting said elements in spaced relationship with the concave side of said objective lens element confronting the convex side of said eye lens element with said optical axis displaced in the same sense from a line joining said geometrical centers.
Claim 5
Dependent Claim
73 words
A reversed Galilean viewfinder for use with a camera having a predetermined optical axis, comprising a negative de-centered objective lens and a positive de-centered eye lens, means for mounting said lenses on a camera in spaced relation with said objective lens positioned to refract a ray parallel to said optical axis away from said optical axis and said eye lens positioned to refract said ray back to substantial parallelism with said optical axis.
Claim 6
Dependent Claim
73 words
A reversed Galilean viewfinder for use with a camera having a predetermined optical axis, comprising a negative de-centered objective lens and a positive de-centered eye lens, means for mounting said lenses on a camera in spaced relation with said objective lens positioned to refract a ray parallel to said optical axis away from said optical axis and said eye lens positioned to refract said ray back to substantial parallelism with said optical axis.
Claim 7
Dependent Claim
63 words
In a Galilean viewfinder, a negarive de-centered eye objective lens and a positive de-centered eye lens, said lens being de-centered in the same sense to cause refractions in opposite senses of parallel rays entering said viewfinder, said objective lens being bent to reduce distortion, said eye lens being bent to reduce coma and field curvature, said eye lens being tilted to reduce astigmatism.
Claim 8
Dependent Claim
63 words
In a Galilean viewfinder, a negarive de-centered eye objective lens and a positive de-centered eye lens, said lens being de-centered in the same sense to cause refractions in opposite senses of parallel rays entering said viewfinder, said objective lens being bent to reduce distortion, said eye lens being bent to reduce coma and field curvature, said eye lens being tilted to reduce astigmatism.
Claim 9
Dependent Claim
179 words
In combination with a camera having a first optical axis, a Galilean viewfinder comprising a plano-concave objective lens element having a second optical axis displaced from its geometrical center, a plano-convex eye lens element having a third optical axis displaced from its geometrical center, means for mounting said objective lens element on said camera with its plane surface facing object space and with said second optical axis substantially parallel to said first optical axis and between the geometrical center of said objective lens element and said first optical axis, and means for mounting said eye lens element on said camera in spaced relation to said objective lens element with its convex surface facing the concave surface of said eye lens and with said third optical axis intersecting the plane of the plane surface of said eye lens element between the geometrical center of said eye lens element and said first optical axis, said third optical axis being inclined to said first optical at an angle selected to minimize astigmatism in a predetermined region of the field of said viewfinder.
Claim 10
Dependent Claim
179 words
In combination with a camera having a first optical axis, a Galilean viewfinder comprising a plano-concave objective lens element having a second optical axis displaced from its geometrical center, a plano-convex eye lens element having a third optical axis displaced from its geometrical center, means for mounting said objective lens element on said camera with its plane surface facing object space and with said second optical axis substantially parallel to said first optical axis and between the geometrical center of said objective lens element and said first optical axis, and means for mounting said eye lens element on said camera in spaced relation to said objective lens element with its convex surface facing the concave surface of said eye lens and with said third optical axis intersecting the plane of the plane surface of said eye lens element between the geometrical center of said eye lens element and said first optical axis, said third optical axis being inclined to said first optical at an angle selected to minimize astigmatism in a predetermined region of the field of said viewfinder.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-20 | 1980-01-19 | 1980-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-20 | 1984-01-19 | 1984-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-20 | 1988-01-19 | 1988-07-20 | $7700.00 | Window Closed / Lapsed |