Patent ID: 7554650
Filing Date: 2009-06-30
Classification: G01C,G01S,G02B,H01S

Abstract:
1. A surveying system, comprising a laser beam projecting device, a projecting optical system for projecting a laser beam from said laser beam projecting device toward a reflecting object, and a photodetection system having a photodetection element and for guiding a reflected laser beam from said reflection object toward said photodetection element, wherein said laser beam projecting device comprises a semiconductor laser light source for emitting a laser beam having a cross-section in an elliptical shape and having P-polarized light, an anamorphic prism for changing the shape of the cross-section of the laser beam into a circular shape, a birefringent optical component for converting the P-polarized light to a circularly polarized light when said laser beam having the P-polarized light transmitted by said anamorphic prism passes through and for converting the circularly polarized light to S-polarized light when the reflected laser beam having the circularly polarized light passes through again, and a wavelength selecting film formed on one surface of said anamorphic prism, wherein said anamorphic prism has a surface tilted in such a manner that an incident angle of the laser beam is in a range of 45° to 80°, and said wavelength selecting film is formed on said titled surface in such a manner that the incident angle of the laser beam is in a range of 45° to 80°, wherein tilting in a range of 45° to 80° of said wavelength selecting film shifts the transmission wavelength range of said P-polarized light to the shorter wavelength side than the transmission wavelength range of said S-polarized light, said wavelength selecting film has a function of a polarization plate to transmit said P-polarized light and to shut off said S-polarized light at the wavelength range of the shifted amount, and wherein said transmission wavelength range of said wavelength selecting film is set so as to include the wavelength of the laser beam emitted from said laser light source.