| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize a photoelectric encoder with the usage of a both-side telecentric optical system. SOLUTION: The photoelectric encoder is provided with the ball lens 60 constituted by a circular half mirror 62, and a pair of hemisphere lenses 64 and 66 fixed on both surfaces thereof back to back; a light source 10 constituted by LED 12 and a collimator lens 14; a reflection type scale 22 into which illumination light enters from the light source 10 through the half mirror 62 of the ball lens 60; an aperture mirror 70 reflecting the center of the light reflected by the scale 22 and passing through the half mirror 62 of the ball lens 60 to the half mirror 62; and a light-receiving element 34. COPYRIGHT: (C)2006,JPO&NCIPI
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