Patent ID: 7362242

Claim:
An optical encoder device for a small-sized motor which includes a code wheel attached to a motor shaft extending outward from the motor, and a photosensor module for detecting rotation of an optical modulation track of the code wheel, the optical encoder device comprising: the photosensor module being composed of a light-receiving element module accommodating a light-receiving element, and a light-emitting element module accommodating a light-emitting element, which modules are separate, paired components; a board unit being fixed to an end surface of the motor, one of the paired light-receiving element module and light-emitting element module being mounted on a printed circuit board of the board unit; and a generally L-shaped module holder being mounted to the board unit, which accommodates the other of the paired light-receiving element module and light-emitting element module, after the code wheel is attached and fixed to the motor shaft along the axial direction of the motor shaft, whereby the light-emitting element and the light-receiving element are positioned such that these elements face each other via the optical modulation track portion of the code wheel.