US Patent No. 10,257,480

PROJECTION DISPLAY APPARATUS AND PROJECTION METHOD FOR PROJECTION DISPLAY APPARATUS


Patent No. 10,257,480
Issue Date April 09, 2019
Title Projection Display Apparatus And Projection Method For Projection Display Apparatus
Inventorship Shinichiro Chikahisa, Tokyo (JP)
Assignee NEC DISPLAY SOLUTIONS, LTD., Tokyo (JP)

Claim of US Patent No. 10,257,480

1. A projection display apparatus, comprising:a light source unit including a plurality of light emitting elements;
an image light generator that modulates light from the light source unit to emit image light;
a projecting unit that projects the image light;
a polarization modulator on which the image light is made incident and that emits light in a particular polarization state;
a depolarizer
which is composed of two wedge-shaped quartz plates that have optical anisotropy, the two wedge-shaped quartz plates being arranged such that their optical axes are oriented at an angle of 45 degrees to each other; and
an illuminating unit,
wherein the illuminating unit includes:
an illuminance uniformizing unit that makes an illuminance of light from the light source unit uniform, an exit surface of the illuminance uniformizing unit being conjugate to a surface of the image light generator on which an image is formed;
a prism unit that makes light that exited from the illuminance uniformizing unit incident on the image light generator and that makes the image light emitted from the image light generator incident on the projecting unit; and
a lens that is arranged on an optical path between the illuminance uniformizing unit and the prism unit; and
wherein the depolarizer is arranged on an optical path between the lens and the prism unit.