To provide a lighting device which is capable of projecting an image having a uniform luminance distribution even in the case that limb darkening can not be avoided due to an angle of incidence on a screen or the like.
A luminance distribution resulting from inverting a luminance distribution of light of a light source is formed by a pair of fly eye optical systems 21d and 21e and a compound superposition lens 21i. In this case, the darkening occurring in a peripheral part due to difference between angles of incidence on the center and the periphery of a screen or the like can be offset by utilizing luminance inversion, so that uniform images free from luminance nonuniformity can be projected. The gradient of the inverted luminance distribution is reduced according as the number of divided lens elements constituting the fly eye optical system 21d is increased. The gradient of the luminance distribution can be adjusted by controlling the number of lens elements constituting the fly eye optical system 21d.
Fujitsuna Hideyoshi
Osamu Suzawa
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