Light source unit able to emit light which is less influenced by interference fringes

Abstract

The invention is characterized in that (1) lens characteristics of a microlens array are made to differ between shining areas on to which laser beams are shone, (2) laser elements are disposed differently so that light distributions thereof are made to differ, or (3) the “collecting degrees” of laser beams by collimator lenses of the laser elements are made to differ from each other or one another, so that interference fringes generated by the laser beams are made less conspicuous.

What is claimed is: 
     
         1 . A light source unit comprising:
 a plurality of light sources which are semiconductor laser beam emitting elements;   a microlens array which includes a plurality of microlenses which are arranged planarly so that optical axes thereof are parallel to one another and which make uniform light beams emitted from the light sources individually; and   a collective lens which collects the light beams from the light sources which are made uniform when they pass through the microlens array in such away that the light beams are irradiated on a predetermined surface, wherein   lens characteristics of the microlenses differ between areas on the microlens array on to which the light beams from the individual light sources are shone individually.   
     
     
         2 . The light source unit according to  claim 1 , wherein
 in the microlens array, lens characteristics of the microlenses are made to differ between areas on the microlens array on to which the light beams from the individual light sources are shone individually by making thicknesses of the microlenses differ between the areas.   
     
     
         3 . The light source according to  claim 1 , wherein
 in the microlens array, lens characteristics of the microlenses are made to differ between areas on the microlens array on to which the light beams from the individual light sources are shone individually by making radii of curvature of surfaces of the microlenses differ between the areas.   
     
     
         4 . The light source according to  claim 1 , wherein
 in the microlens array, lens characteristics of the microlenses are made to differ between areas on the microlens array on to which the light beams from the individual light sources are shone individually by making pitches at which the microlenses are formed differ between the areas.   
     
     
         5 . The light source according to  claim 1 , wherein
 in the microlens array, lens characteristics of the microlenses are made to differ between areas on the microlens array on to which the light beams from the individual light sources are shone individually by using individually materials having different refractive indexes for the areas.   
     
     
         6 . The light source unit according to  claim 1 , wherein
 lens characteristics of the microlenses differ so that shining areas of the light source beams which are shone on to the predetermined surface differ between the light sources.   
     
     
         7 . The light source unit according to  claim 1 , wherein
 lens characteristics of the microlenses are such that respective areas of the individual light source beams shone on to the predetermined surface based on a difference in lens characteristics are reduced within a range which is less than a predetermined magnification in an area ratio with respect to a reference area which is set wider than an effective display area of a display element at the predetermined magnification.   
     
     
         8 . A light source unit comprising:
 a light source which comprises a plurality of laser beam emitting elements, wherein   the plurality of laser beam emitting elements are disposed such that an orientation of a light distribution of a laser beam emitted from one of the plurality of laser beam emitting elements differs from an orientation of light distributions of laser beams emitted from the other laser beam emitting element of the plurality of laser beam emitting elements.   
     
     
         9 . The light source unit according to  claim 8 , wherein
 the one laser beam emitting element is disposed by being rotated about an axis of a laser beam emitted therefrom through an angle which differs from an angle or angles at which the other laser beam emitting element or elements are rotated.   
     
     
         10 . The light source unit according to  claim 9 , wherein
 the plurality of laser beam emitting elements are disposed in positions where they are rotated sequentially through different angles which are multiples of an angle resulting from dividing equally 180 degrees by the number of laser beam emitting elements with respect to an angle at which the laser beam emitting element which constitutes a reference laser beam emitting element is disposed.   
     
     
         11 . The light source unit according to  claim 8 , comprising a microlens array and a collective lens which superpose laser beams emitted individually from the plurality of laser beam emitting elements one on the other or another and correct the laser beams so superposed to a surface of a display element which constitutes a predetermined surface. 
     
     
         12 . The light source unit according to  claim 11 , wherein
 light emitted from the light source is shone on to predetermined shining areas on the microlens array via a dichroic mirror.   
     
     
         13 . The light source unit according to  claim 8 , wherein
 the plurality of laser beam emitting elements make up a light source which shines light in the same wavelength range.   
     
     
         14 . A light source unit, comprising a plurality of light sources that light source elements which emit laser beams and collimator lenses which collect the laser beams emitted from the light source elements are combined therein, wherein pencils of light emitted from the light source elements are made to be collected in different collecting degrees between the light sources respectively. 
     
     
         15 . The light source unit according to  claim 14 , wherein
 the collimator lenses are such that radii of curvature of the collimator lenses differ between the collimator lenses.   
     
     
         16 . The light source unit according to  claim 14 , wherein
 the collimator lenses are such that thickness of the collimator lenses differ between the collimator lenses.   
     
     
         17 . The light source unit according to  claim 14 , wherein
 the collimator lenses are such that materials of the collimator lenses differ between the collimator lenses.   
     
     
         18 . The light source unit according to  claim 14 , wherein
 distances between the light source elements and the collimator lenses of the light sources differ between the collimator lenses.   
     
     
         19 . The light source unit according to  claim 14 , wherein
 the individual light source elements of the plurality of light sources emit light in the same wavelength range.   
     
     
         20 . The light source unit according to  claim 14 , comprising a microlens array and a collective lens which superpose light beams emitted individually from the plurality of light sources one on the other or another and correct the light beams so superposed to a surface of a display element which constitutes a predetermined surface.