Projection display

Abstract

A projection type image display apparatus is provided which includes a housing to hold an optical system including multi-lenses, a polarized-light conversion element and a color separation portion. The housing operates to provide an optical path between a light source, located outside the housing, and penetration-type image display elements and an optical synthesizing portion also located outside of the housing.

1 . A projection-type image display apparatus, comprising the following in a housing thereof:
 a light source;   a lighting optical system;   penetration-type image display elements configured for use of R-color, G-color and B-color;   an optical synthesizing portion; and   a projection lens, wherein:   said projection-type image display elements configured for use of the R-color, G-color and B-color are attached with a cross dichroic prism, which constructs said optical synthesizing portion, in one body, on optical surfaces thereof differing from each other,   said cross dichroic prism attached with said image display elements can be freely and detachably attached, so that an emission surface differing from the surfaces, on which said image display elements are attached, opposes to an incident surface of said projection lens, and also a reflection-type polarizing plate and an absorption-type polarizing plate are disposed, sequentially, between the emission surface of said cross dichroic prism and the incident surface of said projection lens, from the emission surface of said cross dichroic prism, opposing to said cross dichroic prisms, and   the degree of polarization of said reflection=type polarizing plate is larger than that of said absorption-type polarizing plate.   
     
     
         2 . The projection-type image display apparatus, according to  claim 1 , wherein on a side of the incident surface of said projection lens is provided a support member for attaching said cross dichroic prism, on which said image display elements are attached, freely and detachably. 
     
     
         3 . The projection-type image display apparatus, according to  claim 2 , wherein a member configured for use of positioning is attached on said support member, on the side of the incident surface of said projection lens, by fixing said member configured for use of positioning on one surface, on which said cross dichroic prism is not attached and further said reflection-type polarizing plate and said absorption-type polarizing plate are not disposed. 
     
     
         4 . A projection-type image display apparatus, comprising the following is a housing thereof:
 a light source;   a lighting optical system;   penetration-type image display elements configured for use of R-color, G-color and B-color;   an optical synthesizing portion; and   a projection lens, wherein:   said penetration-type image display elements configured for use of the R-color, G-color and B-color are, at least, attached with a cross dichroic prism, which constructs said optical synthesizing portion, in one body together with said cross dichroic prism, on optical paths opposing surfaces of said cross dichroic prism differing from each other,   said cross dichroic prism attached with said image display elements can be freely and detachably attached, so that an emission surface differing from the surfaces, on which said image display elements are attached, opposes to an incident surface of said projection lens, and also a reflection-type polarizing plate and an absorption-type polarizing plate are disposed, sequentially, between the emission surface of said cross dichroic prism and the incident surface of said projection lens, from the emission surface of said cross dichroic prism, opposing to said cross dichroic prisms, and   the degree of polarization of said reflection-type polarizing plate is larger than that of said absorption-type polarizing plate.   
     
     
         5 . The projection-type image display apparatus, according to  claim 4 , wherein on a side of the incident surface of said projection lens is provided a support member for attaching said cross dichroic prism, on which said image display elements are attached, freely and detachably. 
     
     
         6 . The projection-type image display apparatus, according to  claim 5 , wherein a member for use of positioning is attached on said support member, on the side of the incident surface of said projection lens, by fixing said member for use of positioning on one surface, on which said cross dichroic prism is not attached and further said reflection-type polarizing plate and said absorption-type polarizing plate are not disposed. 
     
     
         7 . The projection-type image display apparatus, according to  claim 5 , wherein said cross dichroic prism has reflection-type polarizing prisms, which are fixed on surfaces neighboring with each other, and said R-color, G-color and B-color display elements are attached on said reflection-type polarizing prisms, on surfaces differing thereof from each other.