Image displaying apparatus and color separating-combining optical system
View Patent ↗An image displaying apparatus is capable of maintaining the contrast ratios of displayed images even if the f-value of an optical system of the apparatus is lowered to provide bright images, efficiently utilizing a beam from a light source, minimizing the size and weight of the optical system, and being easy to manufacture. The image displaying apparatus includes first to third reflective polarizing plates ( 120, 121, 122 ) provided for first to third reflective spatial light modulators ( 130, 131, 132 ), respectively. The reflective polarizing plates polarize and separate beams to be injected into the reflective spatial light modulators. In the image displaying apparatus, a color separating optical system has a larger effective diameter than a color composition prism ( 140 ).
1. An image displaying apparatus comprising:
a light source for emitting a beam containing at least three primary colors;
first to third reflective spatial light modulators corresponding to the three primary colors, respectively;
a color separating optical system for separating the beam emitted from the light source into three primary color beams and guiding the three primary color beams toward the first to third reflective spatial light modulators;
first to third wire grid reflective polarizing plates for polarizing and separating the corresponding primary color beam guided by the color separating optical system into a linearly polarized beam of a first polarized state, transmitting and injecting the linearly polarized beam of the first polarized state into the corresponding reflective spatial light modulator, polarizing and separating modulated-and-reflected beam from the corresponding reflective spatial light modulator into a linearly polarized beam of a second polarized state, and reflecting the linearly polarized beam of the second polarized state;
first to third eliminator polarizing plates for eliminating unwanted light from the corresponding color beams modulated by the reflective spatial light modulators and reflected by the wire grid reflective polarizing plates;
a color combining optical system for combining the primary color beams received from the polarizing plates into a composite beam;
an image forming optical unit for receiving the composite beam and forming an image according to the received composite beam; and
wherein the color separating optical system comprises:
a first dichroic mirror for separating the beam from the light source into a first-second primary color beam and a third primary color beam;
a second dichroic mirror for separating the first-second primary color beam into a first primary color beam and a second primary color beam; and
first to third steering mirrors for substantially vertically deflecting the first to third primary color beams, respectively, toward the first to third reflective polarizing plates and first to third reflective spatial light modulators; and
wherein the optical axes of the beams traveling from the first to third steering mirrors to the first to third reflective spatial light modulators are parallel to one another; and
wherein the color separating optical system is disposed in another layer in relation to the layer of the color combining optical system, and the dichroic mirrors in the color separating optical system are disposed outside of respective spatial light modulators and steering mirrors in view from a normal direction of a plane containing the spatial light modulators.
2. The image displaying apparatus of claim 1 , wherein
the color combining optical system is a cross dichroic prism, the first to third reflective spatial light modulators are attached to a planar substrate at three locations around the cross dichroic prism that is also attached to the planar substrate, and beam incident faces of the reflective spatial light modulators are substantially on the same plane.