Patent ID: 7663276

Claim:
An optical encoder device for a small-sized motor comprising a code wheel attached to a motor shaft extending outward from a motor via a bearing accommodated within a bearing-holding portion of an end bell of the motor; and a printed circuit board including a photo sensor module attached thereto such that an optical modulation track portion of the code wheel is positioned in a gap of the photo sensor module, the photo sensor module including a holder made of resin and a light-emitting element and a light-receiving element accommodated in the holder, wherein the printed circuit board is fixed to a flat side wall portion of the motor; the holder has a guide portion which is formed integrally with the holder to project from the holder and comes into contact with an end surface of the end bell and the bearing-holding portion; and the printed circuit board is fixed in a state in which the guide portion is sandwiched between the bearing-holding portion and the printed circuit board while being brought into contact with the end surface of the end bell, whereby the photo sensor module is positioned in thrust and radial directions of the motor.