Abstract: According to the present invention, a projection type image display apparatus enables control of a large amount of light masking through a light-masking unit while maintaining a uniform illumination distribution in an area to be illuminated by the illumination light. The apparatus uses two array lenses on which lens cells are arranged in matrix form, where light-masking unit masks the array lens installed on the light source side in their particular area. The light-masking unit adjusts the amount of light emitted from the light source. The light-masking area of lens cells adjacent to lens cells closest to an optical axis is made smaller than the light-masking area of other cells.

Abstract: If a projection display device includes a shifting mechanism for shifting a projection lens to adjust the direction in which the display projects an optical image, it is difficult to find suitable position where the display should be installed. Thus, the projection lens is fitted with a projection angle adjusting mechanism, which includes an adjusting dial having a scale representing the position of the lens relative to a display element. The projection display device is capable of automatically displaying on the projected optical image a scale image corresponding to the scale. The projection display also is capable of displaying on the projected optical image the position of the optical axis of the projection lens, which can be shifted by the adjusting mechanism.