Patent ID: 9235111
Filing Date: 2016-01-12
CPC Classification: G02F,G03B,H04N

Claim Text:
1. A projection display apparatus configured to project an image onto a target surface, the projection display apparatus comprising: a polarization beam splitter having a polarization splitting plane configured to transmit first polarized light of incident light and to reflect second polarized light of the incident light which has a polarization direction perpendicular to that of the first polarized light; a first phase compensation plate including two layers and configured to provide a retardance which is larger than a sum of λ/4 to polarized light having a wavelength λ from the polarization beam splitter; and a light modulator configured to modulate light from the first phase compensation plate according to an image signal, wherein when a z axis is set to a normal direction of an incident plane of the light modulator, a y axis is set to a direction perpendicular to the z axis and a normal of the polarization splitting plane, an x axis is set to a direction perpendicular to the z axis and the y axis, and an axial angle is defined as an angle of 90° or less between each of optical axis of two layers of the first phase compensation plates and the z axis, each layer has a constant axial angle, and the optical axis of each layer inclines with respect to the x axis in an xz plane, wherein the axial angle of the layer closer to the polarization beam splitter among the two layers is larger than the axial angle of the layer farther from the polarization beam splitter, wherein the following conditional expression is satisfied, where θmax is a maximum value of the axial angle and θmin is a minimum value of the axial angle, wherein the following conditional expression is satisfied, where θave is an average value of axial angles of the two layers.