Optical measurer for lengths using sensor and movable reflector - has two partial mirrors on opposing surfaces of sensor with laser behind one

摘要

A photodetector intercepts the emergent partial mirrors on the sensor and converts to a corresp. electrical signal. The movable measuring reflector has a side turned away from the laser and receives emergent light from the laser for reflection back to the transmissive element. The distance between the partial mirrors is measured such that a standing wave is formed between them. The light transmissive element is a spherical lens (3), the partial mirors being formed on the outer surface on opposite sides. The photodetector (5) is arranged near the lens to receive the light emerging at an angle to the optical axis (8). ADVANTAGE - Very simple construction which can also be very small.