Patent ID: 7505121
Filing Date: 2009-03-17
Classification: G01C

Abstract:
1. A multi-beam optical range sensor comprising: a semiconductor laser; a diffraction grating which has a first region where a first plurality of grooves is formed and a second region where a second plurality of grooves generally perpendicular to the first plurality of grooves is formed and which is configured to diffract and split output light of the semiconductor laser into a plurality of beams; a first and second light-receiving parts, each of which is configured to receive a beam diffracted by the first and second region, respectively, and subsequently reflected by an object, whose absolute distance from the multi-beam optical range sensor is to be measured; a switching part configured to select either one of the first and second regions so as to allow a beam to be outputted from the selected region but inhibit a beam from being outputted from the non-selected region; and a control section configured to process light-reception signals outputted by the first and second light-receiving parts and to drive the semiconductor laser at a specified timing, wherein the switching part comprises a first liquid crystal shutter placed in opposition to the first region of the diffraction grating, and a second liquid crystal shutter placed in opposition to the second region of the diffraction grating.