Clio Technologies, Inc. design and produce special films/plates for backlights:

Beam Angle Expander: This film/plate expands the divergent angle of backlights so that it is suitable for LCDs with a wide viewing angle. The films/plates can be made to increase the viewing angle in x, y, or both directions.

Active area expander: This plate expands the viewing area of the backlight. This product is particularly suitable for backlight displays that have an extremely small border ares.