Optics: measuring and testing – By configuration comparison – With photosensitive film or plate
Patent
1980-07-02
1983-09-06
Rosenberger, R. A.
Optics: measuring and testing
By configuration comparison
With photosensitive film or plate
250237G, 250571, 356386, 356431, G01S 1706, G01B 1104
Patent
active
044026099
ABSTRACT:
Light curtain apparatus incorporating a cyclical scale generator has a light transmitter 12 which projects a light beam onto an optical scanning device 13 located at the focal point of a strip-like concave mirror 14. As a result a parallel scanning light beam 20, which is continuously displaced parallel to itself, is produced in the image space of the concave mirror 14. The scanning light beam 20 is directed through a monitored region 17 towards a retro-reflector 16 and light returned from the retro-reflector 16 is passed via a beam divider 27 to a first light receiving device 18. In this way interruption of the light beam, for example by an object 31, results in interruption of the signal from the first photoelectric receiving device 18. A reflecting scale grid 19 is arranged to intercept a part of the scanning light beam 20 and light reflected from reflective bars of the scale grid 19 is projected, via the concave mirror 14, the optical scanning means 13 and a beam divider 29, onto a bar pattern 21 located in front of a second photoelectric receiving device 11. The divisions of the bar pattern 21 correspond in size with the divisions in the image of the reflecting scale grid 19 which are considerably finer than the cross-sectional dimension of the scanning light beam 20 and this results in the generation of a high frequency pulse signal at the second photoelectric receiver 11 which enables the position or size of the object 31 to be measured with a higher resolution than the cross-sectional dimension of the scanning light beam 20.
REFERENCES:
patent: 3708681 (1973-01-01), Ivers
patent: 3744915 (1973-07-01), Sick
patent: 3829220 (1974-08-01), Parkinson
patent: 4097875 (1978-06-01), Scholten et al.
patent: 4112295 (1978-09-01), Dubik et al.
Biehrer Horst
Fetzer Gunter
Erwin Sick GmbH - Optik-Elektronik
Rosenberger R. A.
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