Patent ID: 6943894

Claim:
A laser distance measuring system comprising: a laser light source that generates at least two interferable light beams with different frequencies on the same optical axis; a parallel reflecting portion that includes a reflecting surface, which is included in an object that moves along a measurement axis and which is arranged on the measurement axis, the parallel reflecting portion returning an incident light beam in a direction opposite that at which it is incident, at a certain spacing from and parallel to the incident light beam; and an interferometer that is positioned between the laser light source and the parallel reflecting portion and that is arranged on the measurement axis; wherein the optical axes of the light beams are displaced in a parallel manner from measurement axis and a portion of the light beams is passed through the interferometer and guided to the parallel reflecting portion, and wherein the interferometer comprises a flat reflector that maintains a light path of a portion of the light beams that is returned by the parallel reflecting portion.