DEVICE FOR AUTOMATIC FOCUSING OF LASER PHOTOPLOTTER Russian patent published in 2003 - IPC

FIELD: laser engineering. SUBSTANCE: device has optically intercoupled radiation source for automatic focusing and recording, beam splitter, focusing lens, recording medium, additional lens, position-sensing photodetecting member, and electrically interconnected electronic signal retrieval circuit and actuating member mechanically coupled with focusing lens. Device also has beam-splitting member made in the form of diffraction grating whose period is longer than T = 2λl/D disposed between radiation source and focusing lens. Position-sensing photodetecting member is provided with at least two separate position-sensing areas of one quadrant photodetector. EFFECT: reduced impact of recording medium surface inclination onto focusing precision of recording beam. 3 cl, 4 dwg