Projection display apparatus and three-plate type of liquid crystal projector using the same

Abstract

A projection display apparatus comprises a reflective LC display device and a polarizing beam splitter having a polarizing separative plane and wired grids. The LC molecules of the device are aligned such that i) a segment on a second subtracted, produced by projecting a major axis of each LC molecule perpendicularly onto the second substrate, makes an angle of 42 to 48 degrees counterclockwise or counterclockwise in relation to a direction of a straight line on the second substrate, formed by projecting each wire grid perpendicularly onto the second substrate and ii) of both ends of the segment, one end meeting an end of each LC molecule, which is positioned nearer to the second substrate than the other end, is positioned nearer to an intersection at which a plane including the polarizing separative plane and a plane including the second substrate mutually intersects, than the other end of the segment.

1 . A projection display apparatus comprising: 
 a reflective liquid crystal display device comprising i) a first substrate having a surface on which a transparent electrode is formed; ii) a second substrate being disposed in parallel to the first substrate with a space left between the first and second electrodes, having thereon a matrix formation composed of reflective electrodes and drive circuits for respective pixels; and iii) a liquid crystal layer composed of nematic liquid crystal having negative dielectric anisotropy and held in the space between the first and second substrates, the liquid crystal composed of liquid crystal molecules to which a pre-tilt angle is given;    a polarizing beam splitter comprising i) a polarizing separative plane positioned obliquely to the first substrate and ii) a wire grid formed on the polarizing separative plane and being in parallel to the first substrate, whereby the polarizing beam splitter allows only a first polarized light component of incident illuminating light to be transmitted therethrough so as to perpendicularly enter the reflective liquid crystal display device and allows a second polarized light component, which is opposite to the first polarized light component, of reflected modulated light emitted from the reflective liquid crystal device to be reflected therefrom so as to produce light to be projected,    wherein the liquid crystal molecules are aligned such that i) a segment on the second subtracted, produced by projecting a major axis of each liquid crystal molecule perpendicularly onto the second substrate, makes an angle of 42 to 48 degrees counterclockwise or counterclockwise in relation to a direction of a straight line on the second substrate, formed by projecting the wire grid perpendicularly onto the second substrate and ii) of both ends of the segment, an end which meets a one end of each liquid crystal molecule, which is positioned nearer to the second substrate than the other end of each liquid crystal molecule, is positioned nearer to an intersection at which a plane including the polarizing separative plane and a plane including the second substrate intersects with each other, than the other end of the segment.    
   
   
       2 . The projection display apparatus of  claim 1 , further comprising a phase compensator being placed between the polarizing beam splitter and the reflective liquid crystal display device so as to be in parallel to the first substrate and having a late-phase axis for the light, 
 wherein, when the segment which makes the angle of 42 to 48 degrees clockwise in relation to the direction of the straight line on the second substrate is defined as a first liquid-crystal alignment condition and the segment which makes the angle of 42 to 48 degrees counterclockwise in relation to the direction of the straight line on the second substrate is defined as a second liquid-crystal alignment condition,    under the first liquid-crystal alignment condition, the late-phase angle of the phase compensator is directed in a counterclockwise angular range of 77-87 degrees in relation to the direction of the projected straight line on the second substrate, and    under the second liquid-crystal alignment condition, the late-phase angle of the phase compensator is directed in a clockwise angular range of 77-87 degrees in relation to the direction of the projected straight line on the second substrate.    
   
   
       3 . The projection display apparatus of  claim 2 , wherein 
 the second substrate has a pixel-mapped area in which the pixels are mapped, the pixel-mapped area being formed into a rectangle whose major edge coincides with a direction presented by the wire grid of the polarizing beam splitter,    the phase compensator is formed to have a plane whose planar shape is larger in size than the pixel-mapped area, formed to have a retardation of 20±5 nm in the plane, and supported rotatably on axis passing centers of both the planar shape and the pixel-mapped area,    under the first liquid-crystal alignment condition, the late-phase axis of the phase compensator is set in a counterclockwise angular range of 3-13 degrees about a direction along a miner edge of the planar shape, and    under the second liquid-crystal alignment condition, the late-phase axis of the phase compensator is set in a clockwise angular range of 3-13 degrees about the direction along the miner edge of the planar shape.    
   
   
       4 . A three-plate type of liquid crystal projector comprising: 
 a color composing prism having three incident planes, two sets of optical multiple layers being arranged plane by plane to receive light of three primary colors, each set of the optical multiple layers being formed in a direction perpendicular to the layers and not only selectively reflecting only light of one color among the light of three primary colors but also transmitting therethrough light of the remaining colors, colors of the reflected light by the two sets of the optical multiple layers being different from each other, and    projection display apparatuses each disposed corresponding to each of the three incident planes of the color composing prism so as to receive modulated light of a color corresponding to an arrangement condition of each set of the optical multiple layers,    wherein each of the projection display apparatuses is made up of a projection display apparatus according to  claim 1 , two projection display apparatuses of the projection display apparatuses being arranged at positions mutually rotated 180 degrees about an output optical axis of the color composing prism.    
   
   
       5 . The three-plate type of liquid crystal projector of  claim 4 , wherein each of the projection display apparatuses has the same alignment condition for the liquid crystal molecules.  
   
   
       6 . The three-plate type of liquid crystal projector of  claim 4 , wherein the liquid crystal molecules of a projection display apparatus of the three projection display apparatuses, which receives the modulated light transmitted through the respective optical multiple layers of the color composing prism, is given an alignment condition different from an alignment condition for the liquid crystal molecules of the two projection display apparatuses.