DUAL-SIDED FILM WITH COMPOUND PRISMS

摘要

Dual-sided optical films have extended prisms formed in one major surface, and extended lenslets formed in an opposite major surface. Some or all of the prisms are compound prisms, in which the two inclined surfaces of each compound prism each include a tip portion, a base portion, and an intermediate portion disposed between the tip portion and the base portion, the intermediate and tip portions forming a concave shape and the intermediate and base portions forming a convex shape, or vice versa. When obliquely incident light, e.g. from a light guide, is incident on the prism side of the film, an output beam emerges from the lenslet side of the film. The output beam has an intensity distribution with a sharp left beam edge and a sharp right beam edge, these beam edges having 10%-to-90% transition angles of no more than 7, 6, 5, 4, 3, or 2 degrees.

主权项

1. An optical system, comprising:
a light guide having a major surface adapted to emit light; a first light source configured to inject light into the light guide along a first direction; and an optical film having opposed first and second structured surfaces, the first structured surface having a plurality of extended prisms formed therein, and the second structured surface having a plurality of extended lenslets formed therein, the prisms and lenslets being arranged in a one-to-one correspondence of lenslets to prisms; and wherein the optical film is disposed proximate the light guide and oriented so that light emitted from the major surface of the light guide enters the optical film through the first structured surface and exits the second structured surface of the optical film, the light exiting the optical film forming a first output beam when the first light source is energized; and wherein the first output beam has a first intensity distribution as a function of angle θ, the first intensity distribution being characterized by a first left beam edge at an angle θLE1, a first right beam edge at an angle θRE1, a first baseline intensity Ibaseline1, and a first maximum intensity Imax1 and a first minimum intensity Imin1 between the first left and first right beam edges; wherein the first left beam edge has a sharpness characterized by a transition angle ΔθLE1, and the first right beam edge has a sharpness characterized by a transition angle ΔθRE1, where ΔθLE1 and ΔθRE1 are measured from 10% to 90% intensity levels between Imax1 and Ibaseline1; and wherein ΔθLE1 is no more than 7 degrees, ΔθRE1 is no more than 7 degrees, Imin1 is at least Ibaseline1+20%*(Imax1−Ibaseline1), and a first beam width equal to θRE1−θLE1 is at least 10 degrees.