OPTICAL MEASURING APPARATUS

Japanese Patent JPH0493706

A

PURPOSE:To obtain a measuring apparatus without effects on the results of measurement even if the intensity of emitted light is changed by constituting the apparatus of a splitting means which divides the light from a light source into a plurality of paths and transfers the light beams, a light projecting means, a light screening means and a signal processing means. CONSTITUTION:The light from a light source 20 is propagated through a light path 25 by way of a half mirror 21 and a liquid crystal 22. The mirror 21 is arranged in the slant state with respect to the light path 25. The light which is reflected from the mirror 21 is reflected from a mirror 23 and cast along a light path 26 through a liquid crystal 24. Then, power is supplied into the liquid crystals 22 and 24 with drivers, and the incident light beams are cut off. When the power feeding is stopped, the incidental light beams are transmitted. The reflected light from an object to be measured 27 is condensed with a condenser lens 28 in a light receiving part and received with a photodetector 29. A signal processing means comprises logarithm converter circuits 33 and 34 and a differential amplifier 35. The light beams through the light paths 25 and 26 having the different light-path lengths are alternately cut off. The difference between luminances of the object to be measured 27 caused by the light beams through the light paths 25 and 26 is computed as the difference between the received light levels through the light path. Thus, the distance to the object to be measured 27 is obtained.

TANAKA HIROKAZU
ISHIKAWA KIYOMITSU
YAMAGUCHI TOMOHIRO

JP21033790A

March 26, 1992

August 10, 1990

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STANLEY ELECTRIC CO LTD

G01C3/06; G01B11/00; (IPC1-7): G01B11/00; G01C3/06

JPS61155909A	1986-07-15
JPS544162A	1979-01-12
JPS60162903A	1985-08-24
JPS56103310A	1981-08-18

Koji Koike

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