US Patent 7748853 Lighting device and projector

A lighting device used for an image display device including a light modulator that modulates light emitted from a light source device includes: a diffractive optical element on which the light emitted from the light source device is made incident and that generates diffractive light from the light made incident thereon and lights the light modulator with the diffractive light; and a light shielding member that is arranged between the diffractive optical element and the light modulator and shields 0-th order light emitted to the light modulator.