Title:
POSITIONING DEVICE FOR EXTREMELY CLOSE INTERVAL OF INFORMATION RETRIEVAL DEVICE
Document Type and Number:
Japanese Patent JPS5720972
Kind Code:
A
Abstract:
PURPOSE:To improve the resolution of a positioning device by performing encoding by a light deflector exercising longitudinal control over using position detection scales shifted in phase longitudinally and a positioner positioning them laterally. CONSTITUTION:On a position detection scale 1 as an optical encoder, (n) columns of stripe-pattern detection marks having a (l) width pitch in the lengthwise direction are formed by being shifted in phase by the same width as an extremely close interval (m). Through a condenser lens 3, a laser light beam from a semiconductor laser 5 is stopped down to the same l/2 with the lateral width of a stripe pattern of the position detection mark on the scale 1 to obtain a position signal. The positioning control of a positioner 2 is exercised by the said position signal regardless of the deflection of a light deflector 4. When a difference between a target address and a current address is P.DELTAC+DELTAD, the light deflector 4 deflects the laser light beam in the longitudinal width direction to shift it to the current-position detection mark by DELTAD on the scale 1, and the positioner 2 is driven by pitch DELTAC to attain positioning.
Inventors:
TSUKADA EIICHI
Application Number:
JP9380380A
Publication Date:
February 03, 1982
Filing Date:
July 11, 1980
Export Citation:
Assignee:
NIPPON TELEGRAPH & TELEPHONE
International Classes:
G06K7/015; G11B21/02; G11B21/08; G11B21/10; (IPC1-7): G06F15/40; G06K7/015; G11B21/08; G11B21/10