Patent ID: 8857996
Filing Date: 2014-10-14
Classification: H04N

Abstract:
1. An illumination optical system comprising: a first lens array including a plurality of lens cells that split a light beam emitted from a light source into a plurality of light beams; a second lens array including lens cells on which the light beams split by the lens cells of the first lens array are incident; an optical element configured to illuminate an image display element by superposing light beams emerging from the second lens array on the image display element; and a polarization conversion element that polarizes the light beams emerging from the second lens array to a uniform polarization direction, the polarization conversion element including a plurality of polarization splitting films, wherein at least one of the first lens array and the second lens array includes two lens cells each having a curved surface that is formed so as to be continuous with a curved surface of an adjacent lens cell, the two lens cells being decentered, wherein, in a cross section in which the two lens cells are decentered, the two lens cells of the first lens array have different radii of curvature, and wherein, when a cross section taken in a direction in which the plurality of polarization splitting films of the polarization conversion element are arranged is taken as a first cross section and a cross section that is taken along an optical axis of the illumination optical system and that is perpendicular to the first cross section is taken as a second cross section, a position at which the light beam split by each of the two lens cells maximally converges in the second cross section is closer to the light source than a position at which the light beam split by each of the two lens cells maximally converges in the first cross section.