TW200734582A - Optical waveguide - Google Patents

Abstract

Provided is an optical waveguide capable of emitting light of uniform distribution from an emitting surface and improving the use efficiency of the light source light. The optical waveguide has a substantially rectangular parallelepiped made of a transparent plastic member. One side of the parallelepiped is an incident surface. One main surface substantially orthogonally intersecting the incident surface is an emitting surface. The other main surface opposing to the emitting surface is a reflection surface. On the reflection surface, a plurality of slopes tilted in the direction of the incident surface with respect to the reflection surface are formed, assuming that the direction parallel to the incident surface is a longitudinal direction. The light coming from the incident surface is deflected to the direction of the emitting surface by the slopes of the reflection surface and emitted from the emitting surface. When the distance from the incident surface to the anti-incident surface is expressed by the horizontal axis, the angle θ defined by the slope and the reflection surface in the distance is expressed by the vertical axis, and the thickness between the reflection surface and the emitting surface is t mm, the range from the incident surface to the anti-incident surface in the horizontal axis direction includes a non-active region where the angle θ is 1 degree x(t/0.6) to 3 degrees x(t/0.6) and a smallest angle region where the angle θ is 1 degree (t/0.6) to 1.3 degrees x(t/0.6) and has an active region where the angle θ at the middle point between the incident surface and the anti-incident surface is 1.2 degrees (t/0.6) to 1.8 degrees (t/0.6) and an anti-incident region where the angle θ is 1.5 degrees x(t/0.6) to 4.5 degrees x (t/0.6). In the active region, the smallest angle region has a start end at the start end of the active region and a terminating end at the point where the straight line connecting the angle θ at the middle point and the start end angle θ of the anti-incident surface region intersects. The angle θ from the terminating end of the smallest angle region to the start end of the anti-incident region increases linearly.