US3732775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Prism viewfinder for mirror reflex cameras
Assignee: HASSELBLOD FV
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Filing: 1971-04-20
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Granted: 1973-05-15
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Expires: 1991-04-20
Abstract
Abstract In a prism viewfinder for mirror reflex cameras having the roof edge of the prism displaced from and opposite to the ray incidence surface of the prism and a plane mirror surface substantially parallel to the ray incidence surface, laterally displaced from and within the range between the roof edge and the ray incidence surface and adapted to direct the ray path out of camera whereby the direction of emergence of the ray path forms an angle of about 45* with respect to the direction of incidence of the ray path; the improvement in which at least the galvanometer of an electric exposure meter is substantially disposed between the plane mirror surface and a plane passing through the ray incidence surface. In the preferred embodiment, a viewfinder adjusting disc is combined with a field lens on the opposite side of the ray incidence surface and spaced therefrom, and measuring circuit components of the exposure meter are substantially disposed between the plane mirror surface and a plane passing through the adjusting disc.
Inventors
- 👤 H Warstat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:51
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/02; G03B19/12
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
150 words
In a prism viewfinder for mirror reflex cameras of the type having a prism the roof edge of which is displaced from and opposite to a ray incidence surface of said prism, and also having a plane mirror surface disposed substantially parallel to said ray incidence surface and laterally displaced therefrom within the range between said roof edge and said ray incidence surface to direct the ray path out of said camera in a direction of emergence which forms an angle of about 45* with respect to the direction of incidence of said ray path; the improvement wherein an electric exposure meter, comprising a galvanometer electrically coupled to a measuring circuit, is incorporated into said prism viewfinder, at least the galvanometer of said electric exposure meter being substantially disposed in the space between said plane mirror surface and a plane extending from and substantially parallel to said ray incidence surface.
Claim 2
Dependent Claim
150 words
In a prism viewfinder for mirror reflex cameras of the type having a prism the roof edge of which is displaced from and opposite to a ray incidence surface of said prism, and also having a plane mirror surface disposed substantially parallel to said ray incidence surface and laterally displaced therefrom within the range between said roof edge and said ray incidence surface to direct the ray path out of said camera in a direction of emergence which forms an angle of about 45* with respect to the direction of incidence of said ray path; the improvement wherein an electric exposure meter, comprising a galvanometer electrically coupled to a measuring circuit, is incorporated into said prism viewfinder, at least the galvanometer of said electric exposure meter being substantially disposed in the space between said plane mirror surface and a plane extending from and substantially parallel to said ray incidence surface.
Claim 3
Dependent Claim
58 words
A prism viewfinder in accordance with claim 1 in which said viewfinder includes an adjusting disc mounted in a plane parallel to and spaced from the ray incidence surface of said prism, at least a portion of said measuring circuit being substantially disposed between the plane mirror surface and the plane in which said adjusting disc is mounted.
Claim 4
Dependent Claim
17 words
A prism viewfinder in accordance with claim 2 wherein the viewfinder adjusting disc comprises a field lens.
Claim 5
Dependent Claim
27 words
A prism viewfinder in accordance with claim 2 wherein said galvanometer includes a movable pointer positioned to extend into the edge zone of said ray incidence surface.
Claim 6
Dependent Claim
39 words
A prism viewfinder in accordance with claim 4 wherein said galvanometer is mounted for rotation about an axis which coincides with the axis of said pointer, and setting means for adjusting the rotational position of said galvanometer and pointer.
Claim 7
Dependent Claim
43 words
A prism viewfinder in accordance with claim 1 including a current source for the measuring circuit of said exposure meteR, said current source also being disposed in said space between the plane mirror surface and the plane extending from said ray incidence surface.
Claim 8
Dependent Claim
32 words
A prism viewfinder in accordance with claim 1 including a light sensitive means in said measuring circuit of said exposure meter, said light-sensitive means being supported adjacent a surface of said prism.
Claim 9
Dependent Claim
26 words
A prism viewfinder in accordance with claim 1 wherein said prism supports electrical switch means forming a portion of the measuring circuit of said exposure meter.
Claim 10
Dependent Claim
18 words
A prism viewfinder in accordance with claim 1 including a support member mounted on the prism roof edge.
Claim 11
Dependent Claim
22 words
A prism viewfinder in accordance with claim 9 wherein said measuring circuit includes a light sensitive means mounted on said support member.
Claim 12
Dependent Claim
26 words
A prism viewfinder in accordance with claim 9 including switch means mounted on said support member, said switch means comprising a portion of said measuring circuit.
Claim 13
Dependent Claim
24 words
A prism viewfinder in accordance with claim 9 wherein a portion of said support member projects into the ray emergence range of said prism.
Claim 14
Dependent Claim
34 words
A prism viewfinder in accordance with claim 11 wherein said switch means comprises switch contacts mounted on said support member, and actuating means for said contacts mounted on a housing cap covering said prism.
Claim 15
Dependent Claim
29 words
A prism viewfinder in accordance with claim 9 including a common housing for said viewfinder and exposure meter, and spring means extending between said housing and said support member.
Claim 16
Dependent Claim
23 words
A prism viewfinder in accordance with claim 14 wherein said housing includes a removable cap, and an eye piece mounted on said cap.
Claim 17
Dependent Claim
18 words
A prism viewfinder in accordance with claim 1 including means for detachably mounting said viewfinder on the camera.
References Cited (Backward Citations)
DE1274437B
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-14 | 1976-11-13 | 1977-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-14 | 1980-11-13 | 1981-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-14 | 1984-11-13 | 1985-05-15 | $7700.00 | Window Closed / Lapsed |