US 2008/0304288 A1 · PLANAR LIGHTING DEVICE

Abstract

The planar lighting device includes a pair of light sources, a light guide plate and a housing. The light guide plate is disposed between the light sources and includes a light exit plane and a pair of opposite light entrance planes respectively provided opposite to the light sources. The planar lighting device thus configured features a heat dissipation structure whereby a heat sink is connected to each of the light sources and heat pipes are attached to the heat sink so as to extend toward the center of the housing. Disclosed is a thin and lightweight planar lighting device suitably used for a large display television or the like, capable of emitting illumination light free from brightness unevenness or with a reduced level of brightness unevenness, allowing increase of dimensions of the display area, and capable of optimally releasing heat generated by the light sources.

Claims22

Dependent claims

A planar lighting device comprising:

a pair of light sources;
a light guide plate being disposed between said pair of light sources and having a sectional shape in a form of a reversed wedge growing wider in a direction in which light beam emitted by each of said pair of light sources travels, said light guide plate including:
a light exit plane;
and
a pair of light entrance planes, each being provided opposite to each of said pair of light sources;
a housing for accommodating said pair of light sources and said light guide plate;
heat sinks, each for absorbing heat generated by each of said pair of light sources, and each being connected to each of said pair of light sources;
and
heat pipes, each for releasing said heat absorbed by each of said heat sinks toward a center area of said housing, and each being disposed on a face of each of said heat sinks so as to extend toward said center of said housing.

6 more elements

A planar lighting device comprising:

a pair of light sources;
a light guide plate being disposed between said pair of light sources and having a sectional shape in a form of a reversed wedge growing wider in a direction in which light beam emitted by each of said pair of light sources travels, said light guide plate including:
a light exit plane;
and
a pair of light entrance planes provided opposite each of said pair of light sources;
a housing for accommodating said pair of light sources and said light guide plate;
a power supply casing mounted on an underside of said housing;
a second duct serving as a separation wall, said second duct for releasing heat generated by said pair of light sources from said underside of said housing as well as heat generated by said power supply casing, and being provided between said underside of said housing and said power supply casing;
and
exhaust means for discharging said heat released in said second duct to an outside, and being provided in said second duct close to a central area of said housing.

7 more elements

Dependencies are inferred from the claim text.

Planar lighting device

Life of this patent

Planar lighting device

Life of this patent

Abstract

Claims22