US3710699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single lens reflex camera with an interchangeable focus screen
Assignee: Canon Inc
•
Filing: 1970-04-17
•
Granted: 1973-01-16
•
Expires: 1990-04-17
Abstract
Abstract A removeable condenser lens is mounted above the focusing screen in an SLR. The photocell must be mounted a fixed distance away from the condenser so that the condenser can swing to be removed. To compensate for any lost light which would be caused by the distance, a lens modifies to light directed at the photocell.
Inventors
- 👤 T Mitani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:59
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/02; G03B19/12; G03B7/00; G03B7/08; G03B7/099; G03B7/0993; G03B7/0997; G03B7/09971; G03B7/09976
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
224 words
A single lens reflex camera, comprising a camera housing having an objective lens for receiving light from scenes to be photographed, a reflex mirror in the housing for directing the light received through the objective lens in a given direction, said housing forming an assembly receiving portion in the path of light from said reflex mirror, photometric means in said housing near said receiving portion, an interchangeable assembly removably set in said receiving portion, said assembly including optical transmission means in a path of substantially all the light from said reflex mirror for transmitting light in the given direction so that images of scenes being photographed can be formed, said optical transmission means including a beam splitter for directing the portion of the light from said reflex mirror in a second direction through said optical transmission means toward said photometric means, said transmission means including an exit plane through which light from the beam splitter passes, said assembly forming a gap between said exit plane and said photometric means, and optical modifying means for modifying light from said beam splitter toward said photometric means so that said photometric means receives a predetermined quantity of light in response to a given light intensity at scenes being photographed, said optical means being formed of a member attached to said transmission means and interchangeable with said assembly.
Claim 2
Dependent Claim
224 words
A single lens reflex camera, comprising a camera housing having an objective lens for receiving light from scenes to be photographed, a reflex mirror in the housing for directing the light received through the objective lens in a given direction, said housing forming an assembly receiving portion in the path of light from said reflex mirror, photometric means in said housing near said receiving portion, an interchangeable assembly removably set in said receiving portion, said assembly including optical transmission means in a path of substantially all the light from said reflex mirror for transmitting light in the given direction so that images of scenes being photographed can be formed, said optical transmission means including a beam splitter for directing the portion of the light from said reflex mirror in a second direction through said optical transmission means toward said photometric means, said transmission means including an exit plane through which light from the beam splitter passes, said assembly forming a gap between said exit plane and said photometric means, and optical modifying means for modifying light from said beam splitter toward said photometric means so that said photometric means receives a predetermined quantity of light in response to a given light intensity at scenes being photographed, said optical means being formed of a member attached to said transmission means and interchangeable with said assembly.
Claim 3
Dependent Claim
38 words
A camera as in claim 1, further comprising a light deflector and an eye piece assembled into a removable unit separately removable from said assembly, said removable unit being adapted to be removed before removal of said assembly.
Claim 4
Dependent Claim
21 words
A single lens reflex camera as in claim 1, wherein said member is cemented to said transmission means at the window.
Claim 5
Dependent Claim
45 words
A camera as in claim 1, wherein said member is composed of a neutral density material whose density is such as to cause said photometric means to receive a predetermined quantity of light in response to a given light intensity at a scene being photographed.
Claim 6
Dependent Claim
35 words
A camera, as in claim 1, wherein said transmission means includes a condensor lens, said beam splitter being formed within said condensor lens, said exit plane being formed at the edge of said condensor lens.
Claim 7
Dependent Claim
21 words
A camera, as in claim 1, wherein said member has a different optical transmission characteristic than that of said transmission means.
Claim 8
Dependent Claim
210 words
A single lens reflex camera, comprising camera housing means and interchangeable viewer means adapted to be mounted on the housing and removed therefrom; said camera housing means including objective lens means for receiving light, and reflex means movable into the path of the light from said objective for directing the light toward said viewer means when said viewer means is mounted in the housing; said viewer means including a screen and optical means for directing the light to a viewer; said housing means including photoelectric means spaced from said optical means, said optical means including beam splitter means for directing a portion of the light from said mirror towards said photoelectric means, said optical means having an exit face through which light from said beam splitter means passes, said photoelectric means being spaced from said viewer means at the exit face and light restricting means mounted on one of said and said photoelectric means for limiting the egress of light from the path between said viewer means and said photoelectric means, said restricting means including an optical elEment having interiorly reflecting surfaces and mounted on said viewer means and extending toward said optical means to close the space between said viewer means, said member covering substantially the entire exit face.
Claim 9
Dependent Claim
210 words
A single lens reflex camera, comprising camera housing means and interchangeable viewer means adapted to be mounted on the housing and removed therefrom; said camera housing means including objective lens means for receiving light, and reflex means movable into the path of the light from said objective for directing the light toward said viewer means when said viewer means is mounted in the housing; said viewer means including a screen and optical means for directing the light to a viewer; said housing means including photoelectric means spaced from said optical means, said optical means including beam splitter means for directing a portion of the light from said mirror towards said photoelectric means, said optical means having an exit face through which light from said beam splitter means passes, said photoelectric means being spaced from said viewer means at the exit face and light restricting means mounted on one of said and said photoelectric means for limiting the egress of light from the path between said viewer means and said photoelectric means, said restricting means including an optical elEment having interiorly reflecting surfaces and mounted on said viewer means and extending toward said optical means to close the space between said viewer means, said member covering substantially the entire exit face.
Claim 10
Dependent Claim
21 words
A camera as in claim 7, wherein said element has a different optical transmission characteristic than that of said optical means.
Claim 11
Dependent Claim
24 words
A camera as in claim 7, wherein said restricting means forms a light filter for limiting the intensity of light to said photoelectric means.
Claim 12
Dependent Claim
27 words
A camera as in claim 7, wherein said restricting means forms light filter means for complementing the light passing therethrough with the light passing through the screen.
Claim 13
Dependent Claim
13 words
A camera as in claim 7, wherein said element includes a prismatic surface.
Claim 14
Dependent Claim
18 words
A camera as in claim 7, wherein said element includes an interior surface extending parallel to the path.
Claim 15
Dependent Claim
178 words
A viewing apparatus for a camera having a housing and a mirror for redirecting light passing through an objective to the viewing apparatus and photoelectric means on the housing spaced from the apparatus, comprising a screen and optical means for directing the light to a viewer, said optical means including beam splitter means for directing a portion of the light from said mirror means toward said photoelectric means, and light restricting means mounted on said optical means for preventing light from said beam splitter means to said photoelectric means from escaping out of the space between said optical means and said photoelectric means and for directing the light between said beam splitter means and said photoelectric means, said restricting means including an interiorly reflective member occupying a portion of the space formed between said optical means and said photoelectric means when the apparatus is mounted on the camera, said optical means having an exit face remote from the beam splitter means and said member covering substantially the entire exit face so as to transmit virtually all light therefrom.
Claim 16
Dependent Claim
178 words
A viewing apparatus for a camera having a housing and a mirror for redirecting light passing through an objective to the viewing apparatus and photoelectric means on the housing spaced from the apparatus, comprising a screen and optical means for directing the light to a viewer, said optical means including beam splitter means for directing a portion of the light from said mirror means toward said photoelectric means, and light restricting means mounted on said optical means for preventing light from said beam splitter means to said photoelectric means from escaping out of the space between said optical means and said photoelectric means and for directing the light between said beam splitter means and said photoelectric means, said restricting means including an interiorly reflective member occupying a portion of the space formed between said optical means and said photoelectric means when the apparatus is mounted on the camera, said optical means having an exit face remote from the beam splitter means and said member covering substantially the entire exit face so as to transmit virtually all light therefrom.
Claim 17
Dependent Claim
32 words
An apparatus as in claim 13, wherein said member includes an interiorly reflecting portion parallel to a path between said beam splitter means and the photoelectric means when the apparatus is mounted.
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) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |