PROJECTION IMAGE DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To reduce the cost of a projection lens by making small-sized a projection image display device which makes illumination luminous flux obliquely incident on reflection type liquid crystal display elements and obliquely taking image luminous flux out. SOLUTION: The projection image display device which makes the illumination luminous flux 11 obliquely incident on the reflection type display elements 1R, 1G and 1B, obliquely takes the image luminous flux 12 out of the reflection type display elements, and projects it by a projection optical system 6 is characterized by that transmission volume type diffraction grating plates 10R, 10G and 10B which reduce and convert the angle of incidence of the illumination luminous flux on the reflection type display elements and transmit the image luminous flux from the reflection type display element are arranged at least on the illumination luminous flux incidence sides of the reflection type display elements.