Laser beam projecting device

Abstract

A laser beam projecting device, comprising a laser light source for emitting a laser beam, a wavelength selecting film for allowing the laser beam from the laser light source to pass, and a birefringent optical member arranged on an optical axis closer to an exit side than the wavelength selecting film, wherein the wavelength selecting film is tilted so that an incident angle of the laser beam is in a range of 45° to 80°.

1 . A laser beam projecting device, comprising a laser light source for emitting a laser beam, a wavelength selecting film for allowing the laser beam from said laser light source to pass, and a birefringent optical member arranged on an optical axis closer to an exit side than said wavelength selecting film, wherein said wavelength selecting film is tilted so that an incident angle of the laser beam is in a range of 45° to 80°.  
     
     
         2 . A laser beam projecting device according to  claim 1 , wherein said laser beam projecting device has an anamorphic prism, and said wavelength selecting film is formed on one surface of wedge-like prisms, which constitute said anamorphic prism.  
     
     
         3 . A laser beam projecting device according to  claim 2 , wherein said wavelength selecting film is formed on an incident surface, which is tilted at a range of 45° to 80° with respect to the laser beam entering said anamorphic prism.  
     
     
         4 . A laser beam projecting device according to  claim 1  or  3 , wherein said wavelength selecting film is tilted in such manner that the incident angle of the laser beam is in a range of 60° to 70°.  
     
     
         5 . A laser beam projecting device according to  claim 1  or  3 , wherein said wavelength selecting film is determined depending on a wavelength and an incident angle of the laser beam.  
     
     
         6 . A laser beam projecting device according to  claim 1  or  2 , wherein said wavelength selecting film is a long-pass filter or a short-pass filter.