EP0007902A1
Expired / Lapsed
EP
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Automatic focusing system
Assignee: Mitsubishi Electric Corp
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Filing: 1979-07-16
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Granted: —
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Expires: 1999-07-16
Abstract
Abstract An automatic focusing system to focus automatically a light on an objective video-disk (4) where a P-N junction element, which is a light emitting portion (15) of a semiconductor light source (14), has a function of a pinhole board in order to avoid a difficult positioning of the pinhole board. The output of the semiconductor light source (14) ischanged accordingto the strength of the light reflected from the surface of the video-disk (4). Hence, the output of the light source (14) is phase detected in a phase detector (12) by comparison with the output of an oscillator (11), and the output of the phase detector (12) is supplied to an actuator (13), causing the automatic focusing of a lens This system may be used in a video-disk reproducing apparatus.
Inventors
- 👤 Kazuo Mitsubishi Denki Kabushiki Kaisha Okada
- 👤 Mitsushige Mitsubishi Denki Kabushiki Kaisha Kondo
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 20:09
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0908; G02; G02B; G02B27/00; G02B27/18; G11B7/0917
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
149 words
1) An automatic focusing apparatus which comprises a semiconductor ray source; focusing means for focusing a ray of said semiconductor ray source on an object substrate and focusing the reflective ray to an emitting part of said semiconductor ray source; driving means for vibrating at a predetermined frequency, a position of a ray spot formed by focusing by said focusing means in optical axial direction; an oscillator for exciting said driving means at a predetermined frequency; a phase detector which detects a variation of output characteristics of said semiconductor ray source induced by the reflective ray reflected by said object substrate to carry out phase detection under using the output of said oscillator as the reference signal; and an actuator which controls said focusing means depending upon the output of said phase detector to coincide the focal point of said ray spot with the surface of said object substrate.
Claim 2
Dependent Claim
149 words
1) An automatic focusing apparatus which comprises a semiconductor ray source; focusing means for focusing a ray of said semiconductor ray source on an object substrate and focusing the reflective ray to an emitting part of said semiconductor ray source; driving means for vibrating at a predetermined frequency, a position of a ray spot formed by focusing by said focusing means in optical axial direction; an oscillator for exciting said driving means at a predetermined frequency; a phase detector which detects a variation of output characteristics of said semiconductor ray source induced by the reflective ray reflected by said object substrate to carry out phase detection under using the output of said oscillator as the reference signal; and an actuator which controls said focusing means depending upon the output of said phase detector to coincide the focal point of said ray spot with the surface of said object substrate.
Claim 3
Dependent Claim
38 words
2) An automatic focusing apparatus according to Claim 1 wherein said semiconductor ray source is vibrated at a predetermined frequency to the optical axial direction to vary the position of said ray spot to the optical axial direction.
Claim 4
Dependent Claim
37 words
3) An automatic focusing apparatus according to Claim 1 wherein said focusing means is vibrated at a predetermined frequency to the optical axial direction to vary the position of said ray spot to the optical axial direction.
Claim 5
Dependent Claim
41 words
4) An automatic focusing apparatus according to one of Claims 1 to 3 wherein a variation of output of said semiconductor ray source induced by the reflective ray reflected by said object substrate is detected to carry out a phase detection.
Claim 6
Dependent Claim
42 words
5) An automatic focusing apparatus according to one of Claims 1 to 3 wherein a variation of terminal voltage of said semiconductor ray source induced by the reflective ray reflected by said object substrate is detected to carry out a phase detection.
References Cited (Backward Citations)
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