Patent ID: 7259898
Filing Date: 2007-08-21
Classification: G02B

Abstract:
1. A display having a first and second direct view modes of operation and comprising: a liquid crystal display device; a backlight disposed behind said display device and arranged, during said first mode, to render an image, displayed by said display device during said first mode, visible throughout an extended viewing region in front of said display device; a first holographic element; and a first front light source disposed in front of said display device and said first holographic element and arranged to be actuated during said second mode, said first holographic element being arranged to redirect light from said first front light source into a part of said extended viewing region so that at least one image displayed by said display device during said second mode is visible only in a restricted portion of said extended viewing region, wherein said first holographic element is a holographic optical element arranged to redirect light from said first front light source to said restricted portion, which comprises at least one spatially limited viewing window, and said backlight is arranged to be deactuated during said second mode, the display further comprising a second holographic optical element and a second front light source disposed in front of said display device, said first and second holographic elements being disposed behind said display device and being arranged to redirect light from said first and second front light sources, respectively, to first and second viewing windows, respectively.