Title:
HIGH-RESOLUTION ABSOLUTE VALUE ENCODER
Document Type and Number:
Japanese Patent JPH04158213
Kind Code:
A
Abstract:
PURPOSE:To enable the execution of high-resolution absolute value inspection having arbitrary resolution by determining absolute value data on each of rough, medium and precise angles and by obtaining continuous absolute value data by combining these absolute value data. CONSTITUTION:A first pattern 11 of which an opening length increases gradually till 180 degrees and decreases gradually in a half cycle of residual 180 degrees in accordance with a rotational angle, a second pattern 12 of which one cycle is four degrees and wherein transmitting and non-transmitting regions are repeated every two degrees, and a third pattern 13 which has a 1/3 cycle, are formed in a rotary slit plate 10. Besides, slits 21a to 23b and photosensors 31a to 33b corresponding to the patterns respectively are disposed in a fixed slit plate 20 and electric signals which the sensors 31a to 33b emit in accordance with the quantities of sensed light are subjected to voltage conversion 34. Pseudo sine signals 41a and 41b of which one cycle is one rotation, and of which phases are shifted by 90 degrees are obtained from the sensors 31a and 31b, while similar signals 42a and 42b/43a and 43b of which the respective brightness patterns are of one cycle are obtained from the sensors 32a and 32b/33a and 33b. These signals are subjected to an interpolation processing 35 at the same timing, absolute value data on each of rough, medium and precise angles thus obtained are combined 36, and thereby continuous absolute data are obtained.
Inventors:
KATO TOSHIO
Application Number:
JP28342390A
Publication Date:
June 01, 1992
Filing Date:
October 23, 1990
Export Citation:
Assignee:
CITIZEN WATCH CO LTD
International Classes:
G01D5/36; (IPC1-7): G01D5/36