ELECTRO-OPTICAL DIMMING SYSTEM
First Claim
1. A dimming system in a projection display, the dimming system comprising:
- a first non-absorbing polarizer, the first non-absorbing polarizer receiving light from a light source and passing at least a portion of the light having a first selected polarization;
a variable polarization rotator, the variable polarization rotator receiving the light having the first selected polarization from the first non-absorbing polarizer and selectively rotating the polarization of the received light;
a first heat absorber; and
a second non-absorbing polarizer, the second non-absorbing polarizer receiving the selectively rotated light from the variable polarization rotator and passing a first portion of the light having a second selected polarization to display optics in the projection display and passing a second portion of the light to the first heat absorber.
1 Assignment
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Accused Products
Abstract
An electronic dimming system for use in projection displays is provided. In a first embodiment, the dimming system comprises a first non-absorbing polarizer, a variable polarization rotator, a second non-absorbing polarizer and a heat absorber. The first non-absorbing polarizer receives light from a light source and passes the light of a selected polarization to the variable polarization rotator. The variable polarization rotator selectively rotates the polarization of the received light. The light passes from the variable polarization rotator to the second non-absorbing polarizer. The second non-absorbing polarizer passes only light of a second selected polarization. The light that passes the second non-absorbing polarizer is passed to the display, where it is used to illuminate the display. The system provides the ability to control the amount of light passed to the display by selectively rotating the polarization of the light with the variable polarization rotator.
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Citations
44 Claims
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1. A dimming system in a projection display, the dimming system comprising:
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a first non-absorbing polarizer, the first non-absorbing polarizer receiving light from a light source and passing at least a portion of the light having a first selected polarization;
a variable polarization rotator, the variable polarization rotator receiving the light having the first selected polarization from the first non-absorbing polarizer and selectively rotating the polarization of the received light;
a first heat absorber; and
a second non-absorbing polarizer, the second non-absorbing polarizer receiving the selectively rotated light from the variable polarization rotator and passing a first portion of the light having a second selected polarization to display optics in the projection display and passing a second portion of the light to the first heat absorber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A dimming system for a projection display, the dimming device comprising:
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a first heat absorber;
a first polarizing beam splitter, the first polarizing beam splitter receiving light from a light source and passing a first portion of the received light having a first selected polarization to a first clean up polarizer, the first polarizing beam splitter passing a second portion of the received light having a second selected polarization to the first heat absorber;
a variable polarization rotator proximate the first clean up polarizer, the variable polarization rotator receiving the first portion of light having the first selected polarization from the first clean up polarizer and selectively rotating the polarization of the received first portion of light; and
a second heat absorber;
a second polarizing beam splitter, the second polarizing beam splitter receiving the selectively rotated light from the variable polarization rotator and passing a first portion of the selectively rotated light having a first selected polarization to display optics in the projection display, the second polarizing beam splitter passing a second portion of the selectively rotated light to the second heat absorber. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A dimming system in a projection display, the dimming system comprising:
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a first polarizer, the first polarizer receiving light from a light source and passing at least a portion of the light having a first selected polarization;
a pair of variable polarization rotators, the pair of variable polarization rotators receiving the light having the first selected polarization from the first polarizer and selectively rotating the received light, the pair of variable polarization rotators selected to have substantially opposite angular variation;
a second polarizer, the second polarizer receiving the selectively rotated light from the variable polarization rotator and passing a first portion of the light having a second selected polarization to display optics in the projection display. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A dimming system in a projection display, the dimming system comprising:
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a first non-absorbing polarizer, the first non-absorbing polarizer receiving light from a light source and passing at least a portion of the light having a first selected polarization;
a variable polarization rotator, the variable polarization rotator receiving the light having the first selected polarization from the first non-absorbing polarizer and selectively rotating the received light, wherein the variable polarization rotator is configured such that different spatial portions of the rotator can selectively rotate the polarization of the received light in different amounts;
a second non-absorbing polarizer, the second non-absorbing polarizer receiving the selectively rotated light from the variable polarization rotator and passing a first portion of the light having a second selected polarization display optics in the projection display. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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Specification