Patent attributes
The present invention provides a distance measuring device, which comprises a light projecting unit for projecting a distance measuring light (22) to an object to be measured, a reference reflection unit (55) provided relatively movable and arranged at a known position so as to traverse the projected distance measuring light, a photodetection unit (7) for receiving a reflection light from the object to be measured as a reflected distance measuring light (22′) and a reflection light from said reference reflection unit as an internal reference light (22″), and a control arithmetic unit (15) for calculating a distance to the object to be measured based on a photodetection signal relating to the reflected distance measuring light and based on a photodetection signal relating to the internal reference light.