Abstract: To reduce an influence of stray light and stably record/reproduce high-quality data in holographic recording/reproduction. A holographic memory device includes an optical system that guides a reference beam to an optical information recording medium at a desired angle of incidence, a control part that controls the angle of incidence of the reference beam generated in the optical system, and a lens part that images the reference beam in a desired position of the optical information recording medium. Further, at least a first light beam at a first angle and a second light beam at a second angle different from the first angle are output from the optical element, and the optical element is provided so that the first light beam may propagate within an effective diameter of the lens part and the second light beam may propagate to an outside of the effective diameter of the lens part.

Abstract: An information display apparatus includes main image tone value modification means for modifying a tone value to compress a tone of a main image, first projection means for projecting the main image having the compressed tone by the main image tone value modification part with a first polarization component, sub-image tone value modification means for compressing tones of the sub-image, then modifying tone values of the sub-image by adding to the tone values after the compression an offset value, the offset value being not less than the maximum tone value of the main image having the compressed tone, correction image generation means for generating the correction image formed by subtracting the tone values of the main image having the compressed tone from the tone values modified by the sub-image tone value modification means, and second projection means for projecting the correction image with a second polarization component different from the first polarization component overlaying to the main image project