Patent ID: 9719811
Date: 2017-08-01
CPC Classifications: G01D

Claim:
1. A photoelectric encoder, comprising: a light source; a scale for generating a light-and-dark pattern of light in a first direction along a measurement axis by light irradiated from the light source; and a light-receiving unit including: a first and second light-receiving element columns each configured from a plurality of light-receiving elements, the light-receiving elements of the first and second element column each being arranged in the first direction at a pitch and configured to detect the light-and-dark pattern of light with the same phase, each of the light-receiving elements having a light-receiving surface having a quadrilateral shape; and a light-blocking layer configured from a light-blocking portion and light-transmitting portions, the light-blocking layer being formed on the light-receiving surfaces of the light-receiving elements, the light-blocking portion configured to block the light-and-dark pattern of light into the light-receiving surfaces, and the light-transmitting portions configured to allow transmission of the light-and-dark pattern of light into the light-receiving surfaces, the first and second light-receiving element columns being disposed staggered in a second direction orthogonal to the first direction such that an arrangement pattern of the light-receiving elements in the first and second light-receiving element columns has the pitch which is the same in the first direction and a phase which differs in the first direction, the light-blocking layer being formed such that the light-transmitting portions on the first light-receiving element column and the light-transmitting portions on the second light-receiving element column do not overlap each other when staggered in the second direction, a width in the first direction of each of the light-transmitting portions being more than ½ of a width in the first direction of the light-receiving surface of each of the light-receiving elements, a single light-transmitting portion being arranged on a middle of each light-receiving surface in the first direction, the light-blocking portion covering both edges along the second direction of each light-receiving surface in the first direction, and all of the light-transmitting portions on the first light-receiving element column and all of the light-transmitting portions on the second light-receiving element column being arranged in the first direction at the pitch, respectively.