Patent ID: 7553025

Claim:
A projection type image display apparatus which modulates light from a light source by a light valve according to picture signals to form an optical image and to enlarge and project it, comprising: a polarization converting unit which aligns polarization directions of the light from the light source and forms P-polarization light or S-polarization light; color separators which separate the polarization light, which is undergone the polarization converting, into individual color lights of red, green and blue; three light valves to which the polarized lights of the separated individual color lights are emitted and which modulate the polarization lights of the individual colors according to picture signals and which are disposed in correspondence with the individual color lights; three polarization splitting sections which are disposed in correspondence with the individual color lights and perform polarization splitting of the light to be emitted to the corresponding light valve among the three light valves and the light modulated by the corresponding light valve; a color-synthesizing part which color-synthesizes the lights undergone the polarization splitting by the three polarization splitting sections; a projection lens unit which enlarges and projects the color-synthesized light beam; and a drive circuit which drives the light valves, wherein: each of the three polarization splitting sections is configured to dispose a polarization splitting layer for polarization splitting of light between a pair of prism materials with an adhesive agent or a tackiness agent which is formed of an optically-transparent medium interposed, and at least one of the three polarization splitting sections is configured to perform polarization splitting of light by diffraction based on a grid structure; and wherein the at least one polarization splitting section has a structure in that the polarization splitting layer is formed of a light reflecting grid member which is arranged in a grid-shaped pattern on an optically-transparent substrate, and an optically-transparent medium is filled between the grid member and the substrate in contact with the grid member surface and the substrate surface, and the grid member and the filled optically-transparent medium are bonded to the substrate with another adhesive agent or tackiness agent formed of an optically-transparent medium interposed.