Title:
LENS POSITION DETECTOR
Document Type and Number:
Japanese Patent JPH03154013
Kind Code:
A
Abstract:
PURPOSE:To obtain the lens position detecting device requiring no light emission element by converting part of incident light which is made incident on a zoom lens into spot light, and receiving it by a photodetector, and obtaining a signal corresponding to a light receiving position. CONSTITUTION:In a crystal frame 3, a photodetector 20 such as a PSD, etc., which can detect continuously a position is placed, and on the other hand, in a lens frame 5, a total reflection mirror for reflecting part of incident light to a zoom lens 1 and bringing spot light to image formation in the photodetector 20 is held. According to this constitution, part of the light which is made incident on the zoom lens 1 is reflected by a total reflection mirror 24 and received by the PSD, and as for two signal currents from the PSD, its current values are compared by an arithmetic circuit 22a and a lens position is detected. Therefore, a lens encoder can be constituted without requiring an exclusive light emission element.
Inventors:
TOKUNAGA TOMOKAZU
Application Number:
JP29451089A
Publication Date:
July 02, 1991
Filing Date:
November 13, 1989
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
G01B11/00; G02B7/08; H04N5/232; (IPC1-7): G01B11/00; G02B7/08; H04N5/232
Attorney, Agent or Firm:
Shigetaka Awano (1 person outside)
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