EP0096570A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
An optical system focus-state detector
Assignee: Olympus Corp
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Filing: 1983-06-06
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Granted: —
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Expires: 2003-06-06
Abstract
Abstract An optical system focus-state detector for photometrically analysing light projected from a source (13,37) to an object (4,32) that is to be viewed or recorded via an optical system (1,31) using an off-set projection of said light, analysis means (11,12,45,63) to detect light reflected back from said object and analyse its intensity distribution relative to the axis of the optical system.
Inventors
- 👤 Yoshio Shishido
- 👤 Susumu Takahashi
- 👤 Atsushi Miyazaki
- 👤 Kazumasa Matsuo
- 👤 Shinichi Nishigaki
- 👤 Shinichi Kato
- 👤 Takeaki Nakamura
- 👤 Akibumi Ishikawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 23:27
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/30; G02B7/32; G02B23/00; G02B23/24; G02B23/2407
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
128 words
An optical system focus-state detector for photometrically analysing light projected from a source on to an object that is to be viewed or recorded, using analysis means arranged in a plane conjugate with the plane of the image that is to be viewed or recorded, in order to determine whether an optical system via which said projected light reflected from the object is returned to said analysis means is correctly focussed, projection means being provided to project light on to said object with an intensity distribution which caries with distance from the optical axis of said system, depending on the distance to said object, and the correctly focussed state is detected by comparison of the photometric outputs from at least two photo-electric sensor surfaces in said analysis means.
Claim 2
Dependent Claim
128 words
An optical system focus-state detector for photometrically analysing light projected from a source on to an object that is to be viewed or recorded, using analysis means arranged in a plane conjugate with the plane of the image that is to be viewed or recorded, in order to determine whether an optical system via which said projected light reflected from the object is returned to said analysis means is correctly focussed, projection means being provided to project light on to said object with an intensity distribution which caries with distance from the optical axis of said system, depending on the distance to said object, and the correctly focussed state is detected by comparison of the photometric outputs from at least two photo-electric sensor surfaces in said analysis means.
Claim 3
Dependent Claim
59 words
A detector as claimed in Claim 1, in which said light is projected to said object via a light transmitting section off-set from the optical axis but within or closely adjacent to said focussing optical system a lens being provided for injecting the light beam from the light source into said transmitting section to pass on to the object.
Claim 4
Dependent Claim
53 words
A detector as claimed in Claim 1 or Claim 2, in which the light beam reflected from the light source is defined by an apertured light stop and at least one lens so that only a part of the visual field is illuminated to form an optical image via said focussing optical system.
Claim 5
Dependent Claim
21 words
A detector as claimed in Claim 3, in which the aperture has the shape of a pinhole,a slit,or an annular gap.
Claim 6
Dependent Claim
22 words
A detector as claimed in Claim 3 or Claim 4, in which said light stop is an apertured coating on said lens.
Claim 7
Dependent Claim
32 words
A detector as claimed in any preceding Claim, in which sensor surfaces are spaced apart on each side of the optical axis on a line parallel to the direction of said off-set.
Claim 8
Dependent Claim
24 words
A detector as claimed in Claim 6, in which the respective path lengths for light from said object to said sensor surfaces are equal.
Claim 9
Dependent Claim
42 words
A detector as claimed in Claim 6, in which the respective light path lengths from the object to said sensor surfaces are made slightly different by arranging them in a stepped or inclined configuration or providing a transparent member on one surface.
Claim 10
Dependent Claim
26 words
A detector as claimed in any preceding Claim, in which said projection means utilise an illuminating optical system in the form of a light-guide fibre bunch.
Claim 11
Dependent Claim
16 words
A detector as claimed in any preceding Claim in which said light source produces infrared light.
Claim 12
Dependent Claim
25 words
A detector as claimed in any preceding Claim, in which a flickering light source is employed and means are provided for amplifying the photometric output.
References Cited (Backward Citations)
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