Spatially switched achromatic compound retarder
First Claim
1. An achromatic compound retarder that exhibits a compound retardance and a compound optic axis orientation, comprising:
- a first passive retarder unit having a predetermined retardance at a design wavelength, and having a predetermined optic axis orientation;
a second passive retarder unit having the same retardance as the first passive retarder unit at the design wavelength, and having substantially the same optic axis orientation as the first passive retarder unit; and
a central retarder unit positioned between the first and second retarder units, the central retarder unit having a retardance π
at the design wavelength, and having an optic axis orientation that varies as a function of position on the central retarder unit, wherein the optic axis orientation varies between at least a first orientation state, in which the compound retardance is substantially achromatic, and a second orientation state.
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Accused Products
Abstract
This invention provides achromatic compound retarders, achromatic polarization switches, and achromatic shutters using the liquid crystal compound retarders. It further provides achromatic variable retardance smectic liquid crystal retarders. The achromatic compound retarder of this invention comprises a central liquid crystal retarder unit and two outer retarders positioned in series with and on either side of the liquid crystal retarder unit. The liquid crystal retarder unit comprises either (1) a rotatable smectic liquid crystal half-wave retarder or (2) first and second liquid crystal variable retarders having retardance switchable between zero and half-wave. The outer retarders have substantially the same retardance and orientation. Design equations determine the retardance of the outer retarders and their orientation relative to the central retarder to obtain a particular achromatic retardance for the compound structure.
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Citations
30 Claims
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1. An achromatic compound retarder that exhibits a compound retardance and a compound optic axis orientation, comprising:
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a first passive retarder unit having a predetermined retardance at a design wavelength, and having a predetermined optic axis orientation; a second passive retarder unit having the same retardance as the first passive retarder unit at the design wavelength, and having substantially the same optic axis orientation as the first passive retarder unit; and a central retarder unit positioned between the first and second retarder units, the central retarder unit having a retardance π
at the design wavelength, and having an optic axis orientation that varies as a function of position on the central retarder unit, wherein the optic axis orientation varies between at least a first orientation state, in which the compound retardance is substantially achromatic, and a second orientation state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A reflection-mode achromatic compound retarder, comprising:
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a first passive retarder unit having a predetermined retardance at a design wavelength, and having a predetermined optic axis orientation; a reflector; and a spatially switched retarder unit positioned between the first retarder unit and the reflector, the spatially switched retarder unit having a retardance π
/2 at the design wavelength, and having an optic axis orientation that varies as a function of position on the central retarder unit, wherein the optic axis orientation varies between at least a first orientation state, in which the compound retardance is substantially achromatic, and a second orientation state. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. An achromatic compound retarder that exhibits a composite optic axis orientation and a composite retardance, comprising:
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a first passive retarder unit having a predetermined retardance at a design wavelength, and having a predetermined optic axis orientation; a second passive retarder unit having the same retardance as the first passive retarder unit at the design wavelength, and having substantially the same optic axis orientation as the first passive retarder unit; and a central retarder unit positioned between the first and second retarder units, the central retarder unit having a retardance π
at the design wavelength, and having an optic axis orientation that switches between at least two orientation states as a function of position on the central retarder unit;wherein the composite optic axis orientation and/or the composite retardance is substantially achromatic at two orientation states of the central retarder unit. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A reflection-mode achromatic compound retarder, comprising:
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a first passive retarder unit having a predetermined retardance at a design wavelength, and having a predetermined optic axis orientation; a reflector; a spatially switched retarder unit positioned between the first retarder unit and the reflector, the spatially switched retarder unit having a retardance π
/2 at the design wavelength, and having an optic axis orientation that switches between at least two orientation states as a function of position on the spatially switched retarder unit;wherein the composite optic axis orientation and/or the composite retardance is substantially achromatic at two orientation states of the spatially switched retarder unit. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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Specification