Optical stack for switchable directional display
AssigneeRealD Spark, LLC
InventorsJonathan Harrold, Michael G. Robinson, Graham J. Woodgate
Life of this patent
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Abstract
A privacy display comprises a spatial light modulator and a compensated switchable guest-host liquid crystal retarder arranged between first and second polarisers arranged in series with the spatial light modulator. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss, whereas off-axis light has reduced luminance. The visibility of the display to off-axis snoopers is reduced by means of luminance reduction over a wide polar field. In a wide angle mode of operation, the switchable liquid crystal retardance is adjusted so that off-axis luminance is substantially unmodified.
Claims21
A display device comprising:
- a spatial light modulator comprising a layer of addressable pixels;
- a display polariser arranged on a side of the spatial light modulator, the display polariser being a linear polariser;
- and
- a guest-host liquid crystal retarder comprising a liquid crystal layer comprising a guest material and a host material, wherein the guest material is an anisotropic material and the host material is a liquid crystal material, the guest-host liquid crystal retarder being arranged on the same side of the spatial light modulator as the display polariser with the display polariser arranged between the guest-host liquid crystal retarder and the spatial light modulator,
- wherein the optical axis of the guest-host liquid crystal retarder has an alignment component perpendicular to the plane of the guest-host liquid crystal retarder in at least a state of the host material.
Dependencies are inferred from the claim text.