Patent ID: 9188728
Filing Date: 2015-11-17
Classification: G02B

Abstract:
1. An illuminating device comprising: a plurality of light sources arranged next to each other in one direction and a light guide plate having an incident surface that opposes the light sources on a side surface thereof, the light guide plate guiding light incident on the incident surface and emitting illuminating light from an emission surface provided on a front surface thereof, wherein the light guide plate includes a plurality of prisms that extend in an optical axis direction of the light sources and are arranged next to each other in a longitudinal direction of the incident surface, the prisms scattering the guided light in the longitudinal direction, at least a top portion of each prism includes a curved portion having a curved shape in cross section, a bottom portion of each prism, the bottom portion extending upward from a surface of the light guide plate, has a radius of curvature greater than that of the top portion, each prism has the shape of an elliptical are having a major axis orthogonal to the longitudinal direction in cross section, and wherein the elliptical arc has an aspect ratio of 1.25 or more, the prisms are formed on the emission surface, and first inclined surfaces that oppose the incident surface in an inclined manner and that are arranged next to each other in the optical axis direction are provided between the prisms, and the light guide plate includes a light guide portion having the incident surface and the emission surface, a low-refractive-index layer that is adjacent to a rear surface of the light guide portion and has a refractive index lower than that of the light guide portion, and a light collecting portion including second inclined surfaces that are arranged next to each other in the optical axis direction, the second inclined surfaces being formed on a surface of the light collecting portion that is opposite the emission surface across the low-refractive-index layer and opposing the incident surface in an inclined manner.