Abstract: An optical device is provided, for example for use as a brightness enhancing film in a display. The device comprises a sheet (31) carrying a plurality of light-concentrating elements in the form of prism-like structures (171). The sheet (31) is non-flat, for example by being bent or curved, in one direction. Each of the prism-like structures (171) has first and second surfaces (34, 35) extending from the sheet (31) and intersecting at a line (33). A line (32) parallel to the viewing direction and passing through the intersection line (33) bisects the opposite surface (36) where it intersects (38) the film (31). When used in a display, such a device provides improved and uniform display brightness across a display of curved or other non-flat shape.

Abstract: An optical device is provided, for example for use as a brightness enhancing film in a display. The device comprises a sheet (31) carrying a plurality of light-concentrating elements in the form of prism-like structures (171). The sheet (31) is non-flat, for example by being bent or curved, in one direction. Each of the prism-like structures (171) has first and second surfaces (34, 35) extending from the sheet (31) and intersecting at a line (33). A line (32) parallel to the viewing direction and passing through the intersection line (33) bisects the opposite surface (36) where it intersects (38) the film (31). When used in a display, such a device provides improved and uniform display brightness across a display of curved or other non-flat shape.

Abstract: A backlight is provided for a transmissive spatial light modulator such as a liquid crystal device (1). The backlight comprises a light source (5), which supplies light through an input edge surface (12) of a non-flat light guide (4) having a front surface (4a) and a rear surface (4b). The rear surface (4b) comprises a plurality of concave features (10), each of which has a surface (11) which faces the input surface (12) and which is oriented so as to direct light towards and out of the front surface (4a). The surfaces (11) have slope angles with respect to a tangent plane to the rear surface (4b) at the feature (10) which vary with distance from the input surface (12) so as to concentrate output light from the light guide (4) into a desired angular output range.