Patent ID: 7196776

Claim:
A distance-measuring system, comprising a light source unit, one projecting optical system having a projecting light optical axis and for projecting distance-measuring light from said light source unit to an object to be measured, a photodetection optical system having a photodetection optical axis and for receiving a distance-measuring light reflected from the object to be measured, and an internal reference optical system for guiding the distance-measuring light from the light source unit to said photodetection optical system as an internal reference light, wherein said light source unit comprises one light source for emitting the distance-measuring light, a first optical path for projecting the distance-measuring light from said light source with a larger spreading angle toward the object to be measured, a second optical path for projecting the distance-measuring light from said light source with a smaller spreading angle toward the object to be measured, an optical fiber arranged on one of the optical paths of said first optical path and said second optical path, and an optical path switching means for guiding the distance-measuring light selectively toward one of the optical paths of said first optical path and said second optical path, and wherein one of said light source unit and said projection optical system has a decentering member for decentering the distance-measuring light with respect to the projecting light optical axis.