Patent ID: 7057159

Claim:
An emitting light source apparatus of a reflection-type for use in an optical encoder which applies light to a reflecting scale having an optical grating formed along an axis of measurement and which receives the reflected light from the scale with a light-receiving element to output a displacement signal, said apparatus comprising: a leadframe disposed opposite to said scale; a light-emitting chip mounted on said leadframe, said light-emitting chip having a light-emitting surface substantially orthogonal to an optical grating surface of said scale and in a direction of the optical grating; and a molded transparent resin sealing both the light-emitting chip and said leadframe, wherein said transparent resin includes a first optical element provided at an end face of said molded transparent resin which faces the light-emitting surface of said light-emitting chip, and a second optical element provided at the other end face of said molded transparent resin which is remote from the light-emitting surface of said light-emitting chip, said first optical element reflecting the light from said light-emitting chip substantially parallel to the optical grating surface and in a direction orthogonal to the direction of the optical grating, said second optical element including a planoconvex cylindrical lens consisting of a flat surface on a side of the lens on which the parallel light from said first optical element is incident and a convex spherical surface on the other side of the lens, said second optical element reflecting the parallel light from said first optical element and focusing the reflected light toward the optical grating and illuminating the optical grating over a specified area in the direction of the optical grating on the optical grating as the focused light is converged toward the optical grating.