DEVICE AND METHOD FOR MEASURING AMOUNT OF MOVEMENT,申请号JP19970318417-传众专利搜索

DEVICE AND METHOD FOR MEASURING AMOUNT OF MOVEMENT

申请公布号：JPH11153454(A)

申请号：JP19970318417

申请日期：1997.11.19

申请公布日期：1999.06.08

申请人：

SOKKIA CO LTD

发明人：CHIBA MINORU

分类号：G01D5/30;G01B11/00;G01D5/244;G01D5/38;(IPC1-7):G01D5/38

主分类号：G01D5/30

摘要：PROBLEM TO BE SOLVED: To provide a device and a method for measuring the amount of movement by which a reference position can be set accurately using a simple optical system without causing the drifting of the reference position even at temperature changes. SOLUTION: When light is applied from a light source to an incremental pattern 5 on which reflection slits 6a, 6b are circumferentially aligned and the amount of movement is calculated from changes in intensity of the diffracted light, the incremental pattern 5 is formed by connecting two diffraction patterns 5a, 5b together into the form of a ring by means of two connecting parts 71 , 72 , the diffraction patterns 5a, 5b having respective different duty ratiosϕA,ϕB, the sum of which is 1. An anti-reflection film 8 is formed on the surface of one of the two connecting parts, and the intensities IR, IT of the reflected and transmitted light are measured to detect the connecting part 72 where the anti-reflection film 8 is not formed, thus setting a reference position.