Contrast polymer dispersed liquid crystal projection display system
First Claim
Patent Images
1. A projection display engine comprising:
- a light source;
a filter adapted to selectively direct light derived from the light source as polarized light, the polarized light comprising one of certain polarization and certain other polarization;
a polymer dispersed liquid crystal display adapted to receive one of the certain polarization and the certain other polarization and to return a polarized image in one of the certain polarization and the certain other polarization, the polarized image being directed as an image to be displayed, some light scattered by the polymer dispersed liquid crystal being blocked from being in the image to be displayed; and
a polarization specific reflector disposed in a path of the polarized image and adapted to direct the certain polarization along a first direction and the certain other polarization along a second direction.
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Abstract
A polymer dispersed liquid crystal projection display is provided that has enhanced contrast. In the projection system using a polymer dispersed liquid crystal display (PDLC), polarized light is used as the light source onto the PDLC. The reflected light maintains its polarization, while the scattered light from the off pixels of the PDLC randomize the polarization. The polarized image is then passed through a polarizing filter which eliminates half of the scattered light, whereas practically all of the polarized image is passed onto the display source. In this way, the contrast between the on and off pixels is effectively doubled.
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Citations
30 Claims
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1. A projection display engine comprising:
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a light source;
a filter adapted to selectively direct light derived from the light source as polarized light, the polarized light comprising one of certain polarization and certain other polarization;
a polymer dispersed liquid crystal display adapted to receive one of the certain polarization and the certain other polarization and to return a polarized image in one of the certain polarization and the certain other polarization, the polarized image being directed as an image to be displayed, some light scattered by the polymer dispersed liquid crystal being blocked from being in the image to be displayed; and
a polarization specific reflector disposed in a path of the polarized image and adapted to direct the certain polarization along a first direction and the certain other polarization along a second direction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A projection system comprising:
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a light source;
a filter adapted to selectively direct light derived from the light source as polarized light, the polarized light comprising one of certain polarization and certain other polarization;
a polymer dispersed liquid crystal display adapted to receive one of the certain polarization and the certain other polarization and to return a polarized image in one of the certain polarization and the certain other polarization, the polarized image being directed as an image to be displayed, some light scattered by the polymer dispersed liquid crystal being blocked from being in the image to be displayed;
a polarization specific reflector disposed in a path of the polarized image and adapted to direct the certain polarization along a first direction and the certain other polarization along a second direction;
a controller adapted to receive video data, the controller coupled to the polymer dispersed liquid crystal display to provide the image; and
a display screen for receiving the image. - View Dependent Claims (11, 12)
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13. A method of enhancing the contrast in a display system, the method comprising:
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selectively directing light derived from a light source as polarized light in one of certain polarization and certain other polarization;
directing the polarized light to a polymer dispersed liquid crystal display, the polymer dispersed liquid crystal display receiving one of the certain polarization and the certain other polarization;
returning a polarized image in one of the certain polarization and the certain other polarization from the polymer dispersed liquid crystal display, some light scattered by the polymer dispersed liquid crystal blocked from being in the polarized image; and
passing the polarized image to a polarization specific reflector for directing the certain polarization along a first direction and the certain other polarization along a second direction. - View Dependent Claims (14, 15)
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16. A projection display engine comprising:
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a light source;
a polarization specific reflector adapted to reflect certain polarization of light derived from the light source;
a polymer dispersed liquid crystal display adapted to receive a portion of the light derived from the light source and to return a polarized image, all the light for imaging by the polymer dispersed liquid crystal display having the same relative polarization from the polarization specific reflector to the polymer dispersed liquid crystal display; and
a filter adapted to selectively direct polarized light from the light derived from the light source, wherein some light scattered by the polymer dispersed liquid crystal display is blocked. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of enhancing contrast in a display system, the method comprising:
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providing polarized light from a light source having a polarization specific reflector that reflects certain polarization;
directing the polarized light to a polymer dispersed liquid crystal display;
reflecting, in a single pass by the polarization specific reflector, all the polarized light for imaging by the polymer dispersed liquid crystal display;
returning a polarized image from the polymer dispersed liquid crystal display; and
passing the polarized light through a polarization selective filter to filter out light polarizations other than the polarization meant for the polarized image. - View Dependent Claims (26, 27, 28, 29, 30)
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Specification