To provide a position detector provided with a constitution capable of prolonging its lifetime.
A linear encoder 33 is provided with a light-emitting part 41, a linear scale 31, formed alternately with a translucent part 31e for transmitting light from the light-emitting part 41 and light-shielding parts 31d for shielding the light from the light-emitting part 41, and a light-receiving part 44 for receiving the light transmitted through the translucent part 31e. The light-receiving part 44 is provided with a first light-receiving element 44a and the third light-receiving element 44c for respectively outputting two signals that differ by 180° in phase. The width H1 of the light-shielding part 31d is formed wider than an arrangement pitch P2, when the first photoreception element 44a and the third photoreception element 44c are arranged, inside a light and dark pitch P1, that is the sum of the width H1 of the light-shielding part 31d and the width H2 of the translucent part 31e.
Fujitsuna Hideyoshi
Osamu Suzawa