ABSOLUTE POSITION LENGTH-MEASUREMENT TYPE ENCODER

• Main Author: KUSANO KOUHEI
• Format: Patent
• Language: English
• Published: 05.03.2009
• 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 provide an absolute position length-measurement type encoder having high reliability by suppressing deterioration of signals due to electric noise. SOLUTION: The absolute position length-measurement type encoder includes: a scale 12; a light source 11 for irradiating the scale 12 with measuring light; a light receiver 14 for receiving the measuring light transmitting the scale 12; and a signal processing circuit 20 for detecting an absolute position of the scale 12 by processing light receiving signals of the light receiver 14. The scale 12 has: a first absolute track 302 having first absolute pattern 32 composed of a first contrast pattern expressing the absolute position; and a second absolute track 303 having a second absolute pattern 33 composed of a second contrast pattern reversing the first contrast pattern. The signal processing circuit 20 generates a differential signal S5 by a first light receiving signal S1 based on the first absolute pattern 32 and a second light receiving signal S2 based on the second absolute pattern 33. COPYRIGHT: (C)2009,JPO&INPIT