US3696724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual beam rangefinder
Assignee: Bell and Howell Co
•
Filing: 1969-12-30
•
Granted: 1972-10-10
•
Expires: 1989-12-30
Abstract
Abstract A rangefinder system is mounted in a camera with a viewfinder system and an objective lens having an afocal lens portion and a prime lens portion between which a pair of light reflecting members, such as mirrors, are mounted offset from the optical axis of the objective lens, so as to not intersect the film image light rays, thereby minimizing light loss to the film and maximizing finder image brightness, and to reflect light rays from the entire scene to a plane in the viewfinder system causing a superimposed image to be viewable when the objective lens is in focus and to cause separate images to be viewable when the lens is not in focus. The mirrors are supported on structures, adjustable during assembly, for enabling correction of divergent or convergent light rays to collimated rays.
Inventors
- 👤 Rudolf Hartmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:15
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/02; G03B19/12; G03B13/00; G03B13/18; G03B13/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
216 words
A rangefinder system to facilitate focusing an objective lens of a camera on a subject, the camera having a viewfinder system and said objective lens defining an optical path between first and second lens cells, said first lens cell transmitting light rays along said optical path for a frame of film in said camera and transmitting light rays along said optical path peripheral to said film frame, the system comprising: a first reflecting means mounted in said optical path between the lens cells of sAid objective lens for intersecting only said light rays peripheral to the film frame and reflecting only said peripheral light rays in a predetermined direction; a second reflecting means mounted in said optical path between said same lens cells of said objective lens for intersecting only other light rays peripheral to the film frame and reflecting only said other peripheral light rays in a predetermined direction; and an optical system arranged in said camera to receive said peripheral light rays reflected by said first and second reflecting means to form a superimposed image in a predetermined plane in said viewfinder system when the objective lens of said camera is in focus on the subject and to form separate images in said plane when the objective lens is not focused on the subject.
Claim 2
Dependent Claim
216 words
A rangefinder system to facilitate focusing an objective lens of a camera on a subject, the camera having a viewfinder system and said objective lens defining an optical path between first and second lens cells, said first lens cell transmitting light rays along said optical path for a frame of film in said camera and transmitting light rays along said optical path peripheral to said film frame, the system comprising: a first reflecting means mounted in said optical path between the lens cells of sAid objective lens for intersecting only said light rays peripheral to the film frame and reflecting only said peripheral light rays in a predetermined direction; a second reflecting means mounted in said optical path between said same lens cells of said objective lens for intersecting only other light rays peripheral to the film frame and reflecting only said other peripheral light rays in a predetermined direction; and an optical system arranged in said camera to receive said peripheral light rays reflected by said first and second reflecting means to form a superimposed image in a predetermined plane in said viewfinder system when the objective lens of said camera is in focus on the subject and to form separate images in said plane when the objective lens is not focused on the subject.
Claim 3
Dependent Claim
36 words
A rangefinder system as claimed in claim 1 wherein the path of the light rays reflected by said first reflecting means is different than the path of the light rays reflected by said second reflecting means.
Claim 4
Dependent Claim
72 words
A rangefinder system as claimed in claim 2 wherein said optical system includes a secondary objective lens and a reflector located between said first and second reflecting means and said viewfinder system, said secondary objective lens being mounted to image the light rays reflected by said first and second reflecting means toward said reflector, and said reflector being mounted to reflect said light rays to said predetermined plane in said viewfinder system.
Claim 5
Dependent Claim
17 words
A rangefinder system as claimed in claim 3 wherein said first and second reflecting means are mirrors.
Claim 6
Dependent Claim
23 words
A rangefinder system as claimed in claim 4 wherein said first and second mirrors are held in first and second mirror support structures.
Claim 7
Dependent Claim
33 words
A rangefinder system as claimed in claim 5 wherein said first and second mirror support structures are each adjustable to compensate for divergent or convergent light rays transmitted to each of said mirrors.
Claim 8
Dependent Claim
115 words
A rangefinder system as claimed in claim 5 wherein each of said first and second mirror support structures comprises: a cylindrical clamp mounted in said camera; a cylindrical bushing held at one end in said cylindrical clamp; a shaft passing through a longitudinal opening in said cylindrical bushing; a cap screw threaded into one end of said cylindrical bushing so as to impinge on one end of said shaft; and a mirror support member springably attached to the other end of said cylindrical bushing and impinging on the other end of said shaft, said mirror support member supporting one of said mirrors at a predetermined angle with respect to the optical axis of said camera.
Claim 9
Dependent Claim
46 words
A rangefinder system as claimed in claim 1 comprising: an occluder mounted in the camera and selectively operable from an ineffective position to an effective position to block out light rays from one of said reflecting means for converting said rangefinder system to a viewfinder system.
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) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |