Method and apparatus to achieve a neutral dark state in image projection systems
First Claim
1. A prism assembly comprising:
- a set of optical components configured to separate light into a set of individual light beams directed to modulating faces of the prism assembly; and
an absorptive element configured to remove tint in a black state of an image modulated by the prism assembly, wherein the absorptive element is located at at least one of an input of the prism assembly or an output of the prism assembly or between two optical components of the prism assembly wherein the absorptive element includes an unbalanced dichroic.
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Accused Products
Abstract
An absorptive layer is added to an image display system. The absorptive layer is selected to compensate for tint in a black state of a displayed image. In a Liquid Crystal On Silicon (LCOS) based light engine, blue wavelengths may cause a predominate tint in black portions of an image (or an entirely black image is tinted blue), and the absorptive layer is calculated to absorb an amount of blue equivalent to the tint. The absorptive layer is, for example, an unbalanced magenta dichroic, or a yellow filter. The yellow filter may be placed at any point in the light chain, including input/output of a kernel, input/output of a projection lens, or portions of a light engine or display screen. An unbalanced magenta may be constructed by adding a yellow filter to an existing magenta dichroic in the kernel design.
6 Citations
28 Claims
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1. A prism assembly comprising:
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a set of optical components configured to separate light into a set of individual light beams directed to modulating faces of the prism assembly; and an absorptive element configured to remove tint in a black state of an image modulated by the prism assembly, wherein the absorptive element is located at at least one of an input of the prism assembly or an output of the prism assembly or between two optical components of the prism assembly wherein the absorptive element includes an unbalanced dichroic. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An unbalanced magenta dichroic, comprising:
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a dichroic element having essentially zero transmission in green light wavelengths, having approximately full transmission of red light wavelengths, and having a percentage less than full transmission in blue light wavelengths; wherein the percentage less than full transmission of blue wavelengths is equivalent to an amount of blue tint in a dark state of an image projection system. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A video projection system, comprising:
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a kernel configured to modulate an input light;
a light engine configured to produce the input light;a lens configured to project the modulated light; and a filter;
wherein the filter includes an unbalanced magenta dichroic and wherein the filter is configured to compensate for a dark state tint that would otherwise be present in the projected modulated light. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method for removing tint in a black state of an image comprising:
adjusting an amount of modulation of a set of at least one colored light beam to compensate for dark-state compensating filter(s) placed in a light path of an image projection system, wherein the image projection system includes; a set of optical components configured to separate light into a set of individual light beams directed to modulating faces of a prism assembly; and an absorptive element configured to remove tint in a black state of an image modulated by the prism assembly, wherein the absorptive element is located at at least one of an input of the prism assembly or an output of the prism assembly or between two optical components of the prism assembly wherein the absorptive element includes an unbalanced dichroic. - View Dependent Claims (27, 28)
Specification