| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical encoder which secure a sufficient amount of light for a light receiving element, and which enables downsizing.SOLUTION: The optical encoder 1 is equipped with: a scale 2 having a graduation 21; a light source 31 emitting light onto the scale 2; a scale side lens 32 transmitting the light emitted by the light source 31 to the scale 2; and a head 3 having the light receiving element 33 which receives the light reflected by the scale 2 through the scale side lens 32. While the light source 31 remains arranged between the scale side lens 32 and the light receiving element 33, the distance between the light source 31 and scale side lens 32 is set to the focal length fs of the scale side lens 32. The optical axis Lsrc of the light source 31 agrees with the optical axis Ls of the scale side lens 32 in the read out direction of the graduation 21, and is spaced apart a predetermined distance D from the optical axis Ls of the scale side lens 32 in the direction orthogonal to the graduation 21. |
