Patent ID: 8851735

Claim:
A uniform reflective light-guide apparatus which can be used with an edge light source, said uniform reflective light-guide apparatus comprising: a light-guiding layer, further having a lateral side thereof to be defined as a light-introducing surface for allowing entrance of lights from the edge light source and a plurality of diffusing particles mixed therein; a reflective layer for reflecting the lights back to the light-guiding layer; and a light-exiting surface perpendicular to the light-introducing surface for allowing at least a portion of the lights in the light-guiding layer to leave the light-guide apparatus therefrom; wherein the reflective layer and the light-guiding layer are manufactured integrally by a co-extrusion process so as to avoid possible existence of an air spacing between the reflective layer and the light-guiding layer; wherein a light-guide coefficient (LGC) for the light-guide apparatus satisfies a limitation of 2.07<LGC<4.23; wherein the LGC is computed as LGC=A/(B+C), the A being an area defined by a light curve in an angle-to-photo intensity plot for exiting light rays with respect to the light-guide apparatus, an L 2 in the plot and an X axis of the plot, the B being an area defined by the light curve, an L 1 in the plot, the L 2 and the X axis, and the C being an area defined by the light curve, the L 1 and the X axis; the plot having an angle θ ranged from 0 to 90 degrees to define the X axis and a corresponding intensity to define a Y axis, the angle θ being an angle at an arbitrary point of the light-exiting surface between a normal line thereof and a corresponding incident ray; the incident ray being able to be 100% reflected back to the light-guiding layer by the reflective layer if the angle θ is greater than a critical angle θc, the L 1 being perpendicular to the X axis to define the critical angle θc, the L 2 being perpendicular to the X axis to define an angle by adding 20 degrees to the critical angle θc.