Patent ID: 8870434
Filing Date: 2014-10-28
Classification: F21V,G02B

Abstract:
1. A planar light guide film for a backlight unit having at least one point light source, the light guide film comprising: a light input surface for receiving light from the point light source; a light redirecting surface for redirecting light received from the light input surface; a light output surface for outputting at least the light redirected from the light redirecting surface; wherein the light input surface further comprises a composite lens structure having a first and second circular tip segment each circular tip segment with a first contact angle, and a first and second circular base segment each circular base segment with a top and bottom contact angle, the contact angles of the circular base segments being less than the contact angle of the circular tip segments; and wherein the first and second circular tip segments satisfies the following equations: wherein x is a value in a direction of the light input surface, y wherein y