Sharp Kabushiki Kaisha Corporation

Other

Kirstin Ann Saynor

Michael John Towler

Martin David Tillin

Sandra Gilmour

Michael Geraint Robinson

Harry Garth Walton

Adrian Marc Simon Jacobs

Elizabeth Jane Acosta

Lesley Anne Judge

Emma Jayne Beynon

A broadband optical retardation device, such as may be used for polarisation encoding of display information or in diffractive optical systems, includes a patterned uniform half wave plate retarder in combination with a non-patterned uniform quarter wave plate retarder having an optic axis oriented at 90&deg; to the xz plane. The patterned retarder consists of alternating first and second regions having first and second optic axes at different orientations to a reference axis, for example at &plus;22.5&deg; and &minus;22.5&deg; to the xz plane. Considering light of wavelength &lgr;&deg; incident on the retarder and linearly polarised in the xy plane, such light is differently polarised by the regions, and the light output by the device includes regions in which the light is right circularly polarised and regions in which the light is left circularly polarised. In the case of incident light of wavelengths greater or less than &lgr;&deg;, the output light becomes progressively more linearly polarised as the wavelengths departs to a greater extent from the ideal value, but not to the same extent as would be the case if the device consisted simply of a patterned single layer acting as a quarter plate retarder.

Broadband optical retardation device

A reflective liquid crystal device comprises a polarizer and a mirror between which are disposed several retarder. At least one of the retarders is a variable liquid crystal element whose optic axis is switchable so as to switch the device between a reflective state and a non-reflective state. In the non-reflective state, the total retardance of the retarders between the polariser and the mirror is equal to an odd number of quarter wavelengths for a wavelength at or adjacent the middle of the visible spectrum.

Reflective liquid crystal device

A reflective liquid crystal device comprises a polariser and a mirror between which are disposed several retarder. At least one of the retarders is a variable liquid crystal element whose optic axis is switchable so as to switch the device between a reflective sate and a non-reflective state. In the non-reflective state, the total retardance of the retarders between the polariser and the mirror is equal to an odd number of quarter wavelengths for a wavelength at or adjacent the middle of the visible spectrum.

An optical device of the present invention, includes: an anisotropic layer containing anisotropic molecules, and an alignment layer adjacent the anisotropic layer. The alignment layer serves to align the anisotropic molecules in an adjacent surface region of said anisotropic layer. The alignment layer also includes a twisted molecular structure so as to define a twisted optical retarder.

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Anglesey, United Kingdom

Kirstin Ann Saynor