Light guide plate and surface light source device

摘要

A light guide plate includes an incident surface on which light outputted from point light sources is incident and an outgoing surface for outputting light incident from the incident surface, wherein a reflection-and-propagation surface for reflecting light toward the outgoing surface is formed in a back surface opposite to the outgoing surface. The outgoing surface is made up of a propagation region adjacent to the incident surface, a diffusion-and-propagation auxiliary region adjacent to the propagation region, and a diffusion-and-propagation region adjacent to the diffusion-and-propagation auxiliary region. Hot spots and bright/dark lines in vicinities of the incident surface are controlled primarily by curved portions of prism upper ends formed in the diffusion-and-propagation region, and viewing-angle characteristics of the light guide plate are controlled primarily by linear portions of the prisms.

主权项

1. A light guide plate comprising:
an incident surface on which light outputted from a plurality of point light sources is incident; an outgoing surface from which light incident from the incident surface is outputted, the outgoing surface being orthogonal to the incident surface; and a reflection-and-propagation surface at which the light incident from the incident surface is reflected so as to be propagated toward the outgoing surface, the reflection-and-propagation surface being opposed to the outgoing surface and being orthogonal to the incident surface, wherein a plurality of prism grooves extending parallel to the incident surface are formed in the reflection-and-propagation surface, a flat surface portion is formed in a propagation region of the outgoing surface adjacent to the incident surface, and a plurality of prism protrusions extending orthogonal to the incident surface are formed in a diffusion-and-propagation region of the outgoing surface adjacent to the propagation region, each of the prism protrusions including a protrusion having a curved portion at its upper end.