Patent ID: 8132917

Claim:
A projection type display device, comprising: a light emitting unit comprising a light source for emitting a coherent light; an image light generating unit that modulates the coherent light emitted by the light emitting unit and generates an image light; a projecting unit that projects the image light; and a phase modulating unit positioned between the light emitting unit and the image light generating unit or between the image light generating unit and the projecting unit, the phase modulating unit comprising a first electrode, a second electrode, and a birefringent material layer comprising a liquid crystal layer positioned between the first electrode and the second electrode, wherein the liquid crystal layer has liquid crystal molecules and at least one of the first electrode and the second electrode is configured to generate a gradient electric field such that at least one of a retardation value and an azimuth direction of a slow axis with respect to an optical axis of an incident light is distributed in different directions or values in a plane orthogonal to the optical axis in accordance with the gradient electric field generated between the first electrode and the second electrode.