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US 5,418,631 AGranted
Edge-lit holographic diffusers for flat-panel displays
AssigneeKaiser Optical Systems
InventorJames M. Tedesco
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AssigneeKaiser Optical Systems
InventorJames M. Tedesco
Estimating the term…
Methods of recording and using holographic diffusers are disclosed for use with edge-lit backlight assemblies for transmissive flat-panel displays such as LCDs. When the holographic diffuser is supported against a surface of a backlight-emitting substrate it is operative to scatter the light in the direction of the display panel largely independent of angle of incidence. The recording methods may be used to produce both transmissive- and reflective-type diffusers, which may be employed simultaneously. In one embodiment a transmissive diffuser is used with a reflector and a cholesteric liquid crystal (CLC) polarizer. In this configuration, scatter lobes exhibiting the correct circular polarization are passed by CLC polarizer, whereas radiation of the opposite handedness is redirected toward the reflector, which converts the handedness into the form passable by the CLC polarizer. A quarter-wave plate, added between the CLC polarizer and the display, is operative to transform the circularly polarized scattered radiation into linearly polarized light, obviating the requirement for an additional rear polarizer on the LCD display. An application incorporating a secondary information source, such as an intensified night-vision image, is also described.
A holographically recorded light diffuser to be used in conjunction with a source of light and a display panel having a back surface to receive light emanating from the diffuser, the diffuser comprising:
A backlight assembly to be used with a flat-panel display having a back surface to receive backlighting, the assembly comprising:
A liquid-crystal display (LCD) panel backlight assembly, comprising:
Dependencies are inferred from the claim text.