Privacy display apparatus
AssigneeRealD Spark, LLC
InventorsGraham J. Woodgate, Jonathan Harrold, Michael G. Robinson
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Abstract
A privacy display comprises a luminance-privacy arrangement and a contrast-privacy arrangement. In a privacy mode of operation, ambient light levels are detected and a visual security level is calculated. At and above a visual security level threshold the luminance-privacy arrangement is operable and below the threshold both the luminance-privacy and contrast-privacy arrangements are operable. Image quality for on-axis users is optimised and high levels of visual security are achieved for off-axis snoopers over a wide range of display illuminance conditions.
Claims16
A display apparatus comprising:
- a display device arranged to display an image, the display device having a selectively operable luminance-privacy optical arrangement arranged on operation to reduce the luminance of the image to an off-axis viewer, and a selectively operable contrast-privacy optical arrangement arranged on operation to reduce the contrast of the image to an off-axis viewer;
- and
- a control system arranged to control the display device, the control system being capable of selectively operating either one or both of the luminance-privacy arrangement and the contrast-privacy arrangement, wherein the display device comprises:
- a spatial light modulator;
- and
- a display polarizer arranged on a side of the spatial light modulator, and
- the luminance-privacy optical arrangement comprises:
- an additional polarizer arranged on the same side of the spatial light modulator as the display polarizer;
- and
- at least one retarder arranged between the additional polarizer and the display polarizer, the at least one retarder including a switchable liquid crystal retarder comprising a layer of liquid crystal material and electrodes arranged to apply a voltage for switching the layer of liquid crystal material, wherein the at least one retarder further includes at least one passive compensation retarder.
A display apparatus comprising:
- a display device arranged to display an image, the display device having a selectively operable luminance-privacy optical arrangement arranged on operation to reduce the luminance of the image to an off-axis viewer, and a selectively operable contrast-privacy optical arrangement arranged on operation to reduce the contrast of the image to an off-axis viewer;
- and
- a control system arranged to control the display device, the control system being capable of selectively operating either one or both of the luminance-privacy arrangement and the contrast-privacy arrangement, wherein the display device comprises:
- a spatial light modulator;
- and
- a display polarizer arranged on a side of the spatial light modulator, and
- the luminance-privacy optical arrangement comprises:
- an additional polarizer arranged on the same side of the spatial light modulator as the display polarizer;
- and
- at least one retarder arranged between the additional polarizer and the display polarizer, the at least one retarder including a switchable liquid crystal retarder comprising a layer of liquid crystal material and electrodes arranged to apply a voltage for switching the layer of liquid crystal material, wherein the additional polarizer is arranged on the output side of the spatial light modulator and the luminance-privacy optical arrangement further comprises a reflective polarizer arranged between the at least one retarder and the display polarizer.
Dependencies are inferred from the claim text.