OPTICAL ENCODER AND ELECTRONIC DEVICE INCLUDING THE OPTICAL ENCODER

• Main Author: ONISHI MINORU
• Format: Patent
• Language: English
• Published: 13.05.2010
• Subjects: ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS; MEASURING; MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR; PHYSICS; TARIFF METERING APPARATUS; TESTING

PROBLEM TO BE SOLVED: To obtain movement information on a moving object by one system of signal lines at the maximum. SOLUTION: Output currents of two photodiodes 15a and 15c which are different in phase by 180°, out of four photodiodes 15a-15d which receive light passing through a slit 12 of the moving object 11, are amplified by amplifiers 16a and 16b and then compared by a comparator 17a, and a transistor TrA is on-off controlled by a signal of the result of comparison. Output currents of the other two photodiodes 15b and 15d are amplified by amplifiers 16d and 16c and then compared by a comparator 17b, and a transistor TrB is on-off controlled by a signal of the result of comparison. Then, the level of an A-phase signal being the drain voltage of the transistor TrA, in relation to the threshold of a consumed current Icc, just after the rise of the signal, is determined, and the direction of movement of the moving object 11 is obtained by the A-phase signal alone. Besides, the amount of movement of the moving object 11 is obtained by counting the frequency of the rise of the A-phase signal and the frequency of the rise and fall thereof in relation to the threshold of the consumed current Icc. COPYRIGHT: (C)2010,JPO&INPIT