Light guide device and a backlight module using the same

Abstract

A light guide device includes a main body and a plurality of parallel elongate first V-shaped microstructures. The main body has an incident surface; an emitting surface adjoining the incident surface; and a reflecting surface opposite to the emitting surface. The first V-shaped microstructures are provided on the reflecting surface. Each of the first V-shaped microstructures has a triangular cross-section having a first base angle nearest the incident surface, a second base angle furthest from the incident surface and a vertex angle. A pitch between adjacent microstructures is configured to be substantially constant. A size of each of the first V-shaped microstructures is defined by the equation is y=9.2637×10x−0.0003x+0.0232, wherein x is a distance from a given first V-shaped microstructures to the incident surface (in units of micrometers), and wherein y is a base width of the given first V-shaped microstructures (in units of micrometers).