Patent ID: 7806530

Claim:
A projector device, comprising: a lamp unit providing a light source; an optical system for separating light from the lamp unit into light of three primary colors; and an image synthesizer for synthesizing the light of three primary colors into color image light, the optical system comprising: on an optical axis of the lamp unit, oppositely arranged first and second integrator lenses having a plurality of cells arranged in the form of a matrix; a polarization beam splitter for extracting only a first component wave out of first and second component waves of light vibrating in orthogonal directions, arranged oppositely to the latter stage second integrator lens; and a slit plate provided with a plurality of slit apertures that allow light incidence on the polarization beam splitter, arranged in contact with or close to a light incidence surface of the polarization beam splitter; and a concave lens arranged between the lamp unit and the slit plate on the optical axis of the lamp unit, the concave lens having a concave surface on a light emergence side of the concave lens and having a light incident side formed as a flat surface perpendicular to the optical axis with a concavity formed on the flat surface only in a central region around the optical axis, the concavity being formed such that the slit plate allows passage of a larger amount of light than that in the case of using an optical component without the concavity formed thereon.