Image displaying apparatus
View Patent ↗An image displaying apparatus employs quartz wave plates and displays images of high contrast. The quartz wave plates in the image displaying apparatus are each arranged between a polarizing beam splitter of a color separating-combining unit and a reflective spatial light modulator. Each of the quartz wave plates is made of two elementary quartz plates. An angle formed between slow axes of the two elemental quartz plates is within a range of 5 minutes to 15 minutes from a right angle.
1. An image displaying apparatus comprising:
a white light source configured to emit a white beam;
a separating-combining unit having wavelength selective wave plates and polarizing beam splitters, configured to receive the white beam and separate the white beam into three primary-color beams and receive reflected beams, combine the reflected beams, and emit the combined beams;
reflective spatial light modulators configured to receive the three primary-color beams, respectively, modulate the received beams, and reflect the modulated beams toward the separating-combining unit;
a projecting unit configured to receive the combined beams and project the combined beams; and
a quartz wave plate arranged between each of the polarizing beam splitters of the separating-combining unit and each of the reflective spatial light modulators, configured to adjust a polarization direction of the beam emitted from the separating-combining unit toward the reflective spatial light modulator, the quartz wave plate having laminated two elemental quartz plates, an angle formed between slow axes of the two elemental quartz plates being within a range of 5 minutes to 15 minutes from a right angle.
2. The image displaying apparatus of claim 1 , wherein
the quartz wave plate is arranged in each of optical paths of the three primary-color beams emitted from the separating-combining unit; and
a total thickness of the quartz wave plate is individually determined according to a wavelength of the primary-color beam to transmit.
3. The image displaying apparatus of claim 1 , wherein the quartz wave plate is provided with, on one or both surfaces thereof, a glass plate having no birefringence.
4. The image displaying apparatus of claim 3 , wherein an external surface of the glass plate is provided with a curvature.
5. The image displaying apparatus of claim 1 , wherein the quartz wave plate is provided with, on one or both surfaces thereof, a glass plate having an external spherical face curved at a curvature radius.