Patent ID: 7619208

Claim:
A photoelectric encoder comprising: a scale having a phase grating formed thereon along a measuring axis; a light source operative to emit light to the scale so as to form a light spot on the phase grating; and a photoreceiver operative to receive reflected light from the scale, wherein the light source and the photoreceiver are disposed so as to be allowed to move relative to the scale at least in a direction along the measuring axis, wherein the light source emits the light to the scale so that the photoreceiver receives the reflected light by the scale, wherein the light source emits light with different wavelengths, wherein the phase grating includes a plurality of reflection portions that respectively reflect the light with different wavelengths, the reflection portions being disposed on a single line along the measuring axis, and wherein the plurality of reflection portions are made of a plurality of color resists, and each of the plurality of color resists reflects or absorbs the light with one of the different wavelengths, the plurality of reflection portions respectively having different depths from a surface of the scale so that each of the plurality of reflection portions reflects the light with one of the different wavelengths in accordance with the depth thereof, and a depth of each of the reflection portions is set as to match reflection or absorption efficiency of light for one of the color resists formed therein.