Timothy D Kelly

US Patent:

8033674, Oct 11, 2011

Filed:

Aug 30, 2010

Appl. No.:

12/871796

Inventors:

Zane Coleman - Chicago IL, US
Terence Yeo - Boston MA, US
Timothy Kelly - Brookline MA, US

Assignee:

Fusion Optix, Inc. - Woburn MA

International Classification:

F21V 9/14

US Classification:

362 19, 362558, 362560, 362607, 362613, 362627, 35948301, 35949301

Abstract:

The present invention provides a polarization-sensitive light homogenizer and a backlight and display using the same. The homogenizer improves the spatial luminance and color uniformity, increases the luminance in a direction normal to the homogenizer and provides increased luminance through polarized light recycling within the light homogenizer and backlight. In one embodiment, the homogenizer includes a polarization-sensitive anisotropic light-scattering (PDALS) region, a non-polarization-sensitive anisotropic light-scattering region, and a substantially non-scattering region. In a further embodiment, the non-scattering region is birefringent. The spatially non-uniform incident light flux from a backlight including one or more non-extended light emitting sources is scattered efficiently by the NPDASL region and is incident on the PDALS region which backscatters light orthogonal to the polarization state desired for efficient illumination of a liquid crystal display panel. The NPDASL and the PDALS form a multiple reflection cavity that will increase the spatial luminance while improving the light recycling of the appropriate polarization state. In a further embodiment the light homogenizer includes at least one of a light collimating region and a light re-directing region.