Abstract: A third input device used in a mouse is constructed to have a wheel holder mounted on a bottom board inside the mouse, a roller, the roller having a closed outer side, an inner side, and a receiving open chamber in the inner side, an encoding wheel mounted inside the roller and pivoted with the roller to the wheel holder, the encoding wheel having a mechanical tooth form, and a locating plate coupled to the inner side of the roller for enabling the roller to be pivoted with the encoding wheel to the wheel holder, the locating plate holding a plurality of probes respectively disposed in contact with the tooth form of the encoding wheel and adapted to output a signal indicative of direction and amount of rotation of the encoding wheel and the roller.

Abstract: A photoconductive encoder structure has a grating cogwheel made of light-pervious materials, a sensor and two luminescence elements perpendicular to each other. An incident surface of the grating cogwheel surrounds a protruding surface, and protruding wheel parts divided in equal arc-shapes surround the grating cogwheel for focusing light from a light source by the protruding surface of the grating cogwheel. Moreover, the light is refracted to the corresponding protruding wheel parts for focusing again. Finally, the light is transmitted to the sensor to generate different phase sequence signals. Owing to the structure, a number of cogs surrounding a grating cogwheel is increased, and, at the same time, the structure does not affect convenience in the production process.