Patent US3687038A successfully refreshed from Google Patents.
US3687038A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Viewfinder system for a single lens reflex camera
Assignee: Nikon Corp
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Filing: 1971-03-31
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Granted: 1972-08-29
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Expires: 1991-03-31
Abstract
Abstract A view finder system for a single lens reflex camera provided with a display member for displaying various required information such as exposure meter needle, f-number scale, shutter speed scale and other characters or index marks. The display member is disposed relative to a penta prism so that a light beam from said display member is totally reflected by one transmitting surface of said penta prism adjacent to a focusing screen disposed therebelow and directed to an ocular disposed behind said penta prism, and an optical reflecting member is interposed between said penta prism and said ocular for reflecting said light beam at least twice to direct it to said ocular, whereby the various required information displayed by said display member can be clearly viewed in the viewfinder''s field of view.
Inventors
- 👤 Tadashi Kawakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:31
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/02; G03B19/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
179 words
A viewfinder system for a single lens reflex camera comprising: a focusing screen; an ocular; a penta prism positioned to direct a first light beam passing through the focusing screen into the ocular; a display member for displaying various required information such as an exposure meter needle, an f-number scale, a shutterspeed scale and other characters or index marks, wherein said penta prism has a front surface which transmits therethrough a second light beam from the display member; a first optical reflecting member positioned to direct the second light beam from the display member through the front surface of the prism for reflection on a surface of said prism adjacent said focusing screen; second optical reflecting means interposed between said penta prism and the ocular for at least twice reflecting said second light beam received from the prism and for directing said second light beam into the ocular; wherein the length of the light path from said display member to the ocular is substantially equal to the length of the light path from the focusing screen to the ocular.
Claim 2
Dependent Claim
179 words
A viewfinder system for a single lens reflex camera comprising: a focusing screen; an ocular; a penta prism positioned to direct a first light beam passing through the focusing screen into the ocular; a display member for displaying various required information such as an exposure meter needle, an f-number scale, a shutterspeed scale and other characters or index marks, wherein said penta prism has a front surface which transmits therethrough a second light beam from the display member; a first optical reflecting member positioned to direct the second light beam from the display member through the front surface of the prism for reflection on a surface of said prism adjacent said focusing screen; second optical reflecting means interposed between said penta prism and the ocular for at least twice reflecting said second light beam received from the prism and for directing said second light beam into the ocular; wherein the length of the light path from said display member to the ocular is substantially equal to the length of the light path from the focusing screen to the ocular.
Claim 3
Dependent Claim
29 words
A viewfinder according to claim 1, wherein said second optical reflecting means is mounted on a face of the penta prism opposed to said front surface of said prism.
Claim 4
Dependent Claim
33 words
A viewfinder according to claim 1, in which said second optical reflecting means has a pair of opposed light transmitting surfaces disposed in parallel with a rear light transmitting surface of said prism.
Claim 5
Dependent Claim
175 words
A viewfinder system for a single lens reflex camera comprising: a focusing screen; an ocular; a penta prism having a front surface and a rear surface, wherein said prism is for receiving a first light beam from the focusing screen and for directing the light beam through said rear surface and into the ocular; a display member for displaying various required information such as an exposure meter needle, an f-number scale, a shutter-speed scale and other characters or index marks; means for directing a second light beam from said display member through said front surface of said penta prism, and through said rear surface of said prism and into said ocular; optical reflecting means interposed between said penta prism and the ocular for at least twice reflecting said second light beam, and for passing said first light beam directly therethrough and into said ocular; wherein the length of the light path from said display member to the ocular is substantially equal to the length of the light path from the focusing screen to the ocular.
Claim 6
Dependent Claim
175 words
A viewfinder system for a single lens reflex camera comprising: a focusing screen; an ocular; a penta prism having a front surface and a rear surface, wherein said prism is for receiving a first light beam from the focusing screen and for directing the light beam through said rear surface and into the ocular; a display member for displaying various required information such as an exposure meter needle, an f-number scale, a shutter-speed scale and other characters or index marks; means for directing a second light beam from said display member through said front surface of said penta prism, and through said rear surface of said prism and into said ocular; optical reflecting means interposed between said penta prism and the ocular for at least twice reflecting said second light beam, and for passing said first light beam directly therethrough and into said ocular; wherein the length of the light path from said display member to the ocular is substantially equal to the length of the light path from the focusing screen to the ocular.
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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) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |