Liquid crystal display and reflective diffuser therefor including a reflection cavity section and an illumination cavity section

A diffuser for backlighting a display panel with a selected display area, said diffuser comprising:

• a body of opaque material consisting of a white polycarbonate plastic shell and having a relatively flat surface for positioning adjacent to a display panel and an opposite surface;
• means defining a cavity in said party, said cavity having a first section with a mouth at said flat surface whose area is comparable to that of the display area, and highly reflective walls, at least one of which walls extends from said flat surface towards that opposite surface to define a ramp, said cavity also having a second section intercepting said first cavity section near the foot of said ramp so that when light propagates from the second cavity section into the first cavity section, the walls of the first cavity section, distribute by reflection substantially all of that light and said ramp redirectes that light to the mouth of said first cavity section from which the light propagates as a uniformly intense diffuse emanation.

A liquid crystal display assembly comprising:

• a circuit board having a plurality of light sources mounted thereon;
• overlying the circuit board and the light sources, a shell of opaque material, means defining a cavity in the shell, said cavity having a reflection cavity section with an unobstructed mouth at the top of the shell and a highly reflective inclined bottom surface opposite said mouth, said cavity also having an illumination cavity section with a mouth at the bottom of the shell for receiving the light sources, the illumination cavity section having a highly reflective surface facing the reflection cavity section, the boundary between the two cavity sections being at the foot of said inclined bottom surface, and a liquid crystal display panel directly overlying the unobstructed mouth of the reflection cavity section.

A liquid crystal display assembly comprising

• a circuit board having a plurality of light sources mounted thereon;
• overlying the circuit board and the light sources, a shell of opaque white polycarbonate plastic material, means defining a cavity in the shell, said cavity having a reflection cavity section with a mouth at the top of the shell and a highly reflective inclined bottom surface opposite said mouth, said cavity also having an illumination cavity section with a mouth at the bottom of the shell for receiving the light sources, the illumination cavity section having a highly reflective surface facing the reflection cavity section, the boundary between the two sections being at the foot of said inclined bottom surface.