Patent ID: 8687937

Claim:
A light-guide module comprising: a light-guide strip having opposite first and second ends, a light-entry surface disposed at said first end, a light-exit surface extending between said first and second ends, and first and second working surfaces disposed parallel to each other and extending between said first and second ends, each of said first and second working surfaces being connected to said first end, said second end, and said light-exit surface, one of said first and second working surfaces defining a light-scatter zone and including a plurality of micro-scatter structures that are disposed within said light-scatter zone and that configure said light-scatter zone with a light-scattering ability that varies from said first end to said second end, each of said first and second working surfaces having an area greater than that of said light-exit surface; and a reflecting element disposed to reflect light that exits from said light-guide strip via said first and second working surfaces back into said light-guide strip via said first and second working surfaces, respectively; wherein said light-scatter zone satisfies the conditions of: Ra (0.75 L )/ Ra (0.25 L )â‰§2 Ra (0.95 L )/ Ra (0.25 L )â‰§5 wherein L represents a length of said light-scatter zone from said first end to said second end, and Ra(0.25L), Ra(0.75L), and Ra(0.95L) represent roughness of said light-scatter zone at distances of 25%, 75%, and 95% of the length of said light-scatter zone from said first end toward said second end, respectively.