Optical encoder

An optical encoder, including a light source, a reflective grating of a predetermined form and a fixed pitch, a light transmitting grating of a predetermined form and a fixed pitch, and photodetectors with light receiving surfaces of predetermined form and a predetermined pitch that receive a reflected image produced by light from the light source that has passed through the light transmitting grating and been reflected by the reflective grating, the optical encoder detecting at least a speed of relative movement of the reflective grating and the light transmitting grating, based on detection signals produced by the photodetectors,

• the optical encoder comprising:
• a reflective grating plate in which the reflective grating is formed;
• and
• a semiconductor substrate in which the light transmitting grating and the photodetectors are formed with parts of the light transmitting grating and the photodetectors in alternating positions,
• the light transmitting grating being one of slits for transmitting light that are formed in the semiconductor substrate and thin-film parts for transmitting light that are formed in the semiconductor substrate, and
• a detection signal obtained from a first group of photodetectors, out of the photodetectors formed in the semiconductor substrate, having a phase difference of 90° with a detection signal obtained from a second group of photodetectors, out of the photodetectors formed in the semiconductor substrate.

An optical encoder, including a light source, a reflective grating of a predetermined form and a fixed pitch, a light transmitting grating of a predetermined form and a fixed pitch, and photodetectors with light receiving surfaces of predetermined form and a predetermined pitch that receive a reflected image produced by light from the light source that has passed through the light transmitting grating and been reflected by the reflective grating, the optical encoder detecting at least a speed of relative movement of the reflective grating and the light transmitting grating, based on detection signals produced by the photodetectors,

• the optical encoder comprising:
• a reflective grating plate in which the reflective grating is formed;
• and
• a semiconductor substrate in which the light transmitting grating and the photodetectors are formed,
• the light transmitting grating being one of slits for transmitting light that are formed in the semiconductor substrate and thin-film parts for transmitting light that are formed in the semiconductor substrate,
• a first region, in which the photodetectors arranged at predetermined intervals, and a second region, in which parts of the light transmitting grating are arranged at predetermined intervals, being formed in the semiconductor substrate, and
• a detection signal obtained from a first group of photodetectors that are located at odd-numbered positions in the first region having a phase difference of 180° with a detection signal obtained from a second group of photodetectors that are located at even-numbered positions in the first region.

An optical encoder, including a light source, a reflective grating of a predetermined form and a fixed pitch, a light transmitting grating of a predetermined form and a fixed pitch, and photodetectors with light receiving surfaces of predetermined form and a predetermined pitch that receive a reflected image produced by light from the light source that has passed through the light transmitting grating and been reflected by the reflective grating, the optical encoder detecting at least a speed of relative movement of the reflective grating and the light transmitting grating, based on detection signals produced by the photodetectors,

• the optical encoder comprising:
• a reflective grating plate in which the reflective grating is formed;
• and
• a semiconductor substrate in which the light transmitting grating and the photodetectors are formed,
• the light transmitting grating being one of slits for transmitting light that are formed in the semiconductor substrate and thin-film parts for transmitting light that are formed in the semiconductor substrate,
• a first region, in which the photodetectors are arranged at predetermined intervals, a second region, in which the photodetectors are arranged at predetermined intervals, and a third region, in which parts of the light transmitting grating are arranged at predetermined intervals, being formed in the semiconductor substrate, and
• detection signals obtained from adjacent photodetectors in the first region and the second region having a phase difference of 270°.

An optical encoder, including a light source, a reflective grating of a predetermined form and a fixed pitch, a light transmitting grating of a predetermined form and a fixed pitch, and photodetectors with light receiving surfaces of predetermined form and a predetermined pitch that receive a reflected image produced by light from the light source that has passed through the light transmitting grating and been reflected by the reflective grating, the optical encoder detecting at least a speed of relative movement of the reflective grating and the light transmitting grating, based on detection signals produced by the photodetectors,

• the optical encoder comprising:
• at least one planar LED as a light source;
• a reflective grating plate in which the reflective grating is formed;
• and
• a semiconductor substrate in which the light transmitting grating and the photodetectors are formed,
• the light transmitting grating being one of slits for transmitting light that are formed in the semiconductor substrate and thin-film parts for transmitting light that are formed in the semiconductor substrate.