DISPLAY DEVICE
According to one embodiment, a display device includes a liquid crystal panel, an illumination device, and an optical sheet provided between the liquid crystal panel and the illumination device. The illumination device includes a plurality of light sources, a first light guide which has a first side surface facing the light sources, and a second side surface on a side opposite to the first side surface, a second light guide which faces the first light guide and has a third side surface, a transparent element which has a first plane being in contact with the second side surface and the third side surface, and a second plane located on a side opposite to the first plane and inclining with respect to the first plane, and a reflective element which faces the second plane.
1 . A display device comprising:
a liquid crystal panel;
an illumination device which faces the liquid crystal panel; and
an optical sheet provided between the liquid crystal panel and the illumination device, wherein
the illumination device comprises:
a plurality of light sources;
a first light guide which has a first side surface facing the plurality of light sources, and a second side surface on a side opposite to the first side surface;
a second light guide which faces the first light guide and has a third side surface;
a transparent element which has a first plane being in contact with the second side surface and the third side surface, and a second plane located on a side opposite to the first plane and inclining with respect to the first plane; and
a reflective element which faces the second plane.
2 . The display device of claim 1 , wherein
the first light guide is a glass substrate comprising:
a base body which has a first refractive index; and
a plurality of optical waveguides which extend from the first side surface toward the second side surface inside the base body, are formed by branching on a way, and have a second refractive index higher than the first refractive index, and
the first light guide has a constant thickness from the first side surface to the second side surface.
3 . The display device of claim 2 , wherein
the plurality of light sources include a first light source configured to emit a red laser beam, a second light source configured to emit a green laser beam and a third light source configured to emit a blue laser beam,
the plurality of optical waveguides include a first optical waveguide for transmitting the red laser beam, a second optical waveguide for transmitting the green laser beam and a third optical waveguide for transmitting the blue laser beam, and
the first optical waveguide, the second optical waveguide and the third optical waveguide are located hierarchically in a thickness direction of the first light guide without intersecting with each other and do not bend in the thickness direction.
4 . The display device of claim 3 , wherein
each of the red laser beam, the green laser beam and the blue laser beam is linearly polarized light, and
the transparent element is formed of a polymer in which refractive index anisotropy is nearly zero.
5 . The display device of claim 4 , wherein
the second light guide is formed of a polymer in which refractive index anisotropy is nearly zero.
6 . The display device of claim 1 , wherein
the plurality of light sources include a first light source configured to emit a red laser beam, a second light source configured to emit a green laser beam and a third light source configured to emit a blue laser beam,
each of the red laser beam, the green laser beam and the blue laser beam is linearly polarized light, and
the first light guide is formed of a polymer in which refractive index anisotropy is nearly zero.
7 . The display device of claim 6 , wherein
the transparent element is formed of a polymer in which refractive index anisotropy is nearly zero.
8 . The display device of claim 7 , wherein
the second light guide is formed of a polymer in which refractive anisotropy is nearly zero.
9 . The display device of claim 1 , wherein
the second light guide is provided between the first light guide and the optical sheet.
10 . The display device of claim 1 , wherein
the first light guide is provided between the second light guide and the liquid crystal panel.
11 . The display device of claim 1 , wherein
the reflective element is a reflective layer formed in the second plane.
12 . The display device of claim 1 , wherein
the reflective element is a metallic body or a reflector in which a reflective layer is formed on a surface of a block.
13 . The display device of claim 1 , wherein
in plan view, each of the second side surface and the third side surfaces includes a first linear portion, a second linear portion which is closer to the first side surface than the first linear portion, and a third linear portion which connects the first linear portion and the second linear portion to each other.
14 . The display device of claim 13 , wherein
the transparent element is provided between the first linear portion and the reflective element and between the second linear portion and the reflective element.
15 . A display device comprising:
a liquid crystal panel;
an illumination device which faces the liquid crystal panel; and
an optical sheet provided between the liquid crystal panel and the illumination device, wherein
the illumination device comprises:
a plurality of light sources;
a first light guide which has a first side surface facing the plurality of light sources, and a second side surface on a side opposite to the first side surface;
a second light guide which has a third side surface;
a transparent element which has a first plane being in contact with the second side surface and the third side surface, a second plane located on a side opposite to the first plane and inclining with respect to the first plane, an upper surface located on a side facing the optical sheet between the first plane and the second plane, and a lower surface on a side opposite to the upper surface; and
a reflective element which faces the second plane,
the second light guide is provided between the first light guide and the optical sheet, and
in the transparent element, a width of the lower surface is less than a width of the upper surface.
16 . The display device of claim 15 , wherein
the first light guide is a glass substrate which has a refractive index distribution for forming a plurality of optical waveguides, and
each of the transparent element and the second light guide is formed of a polymer in which refractive index anisotropy is nearly zero.
17 . The display device of claim 15 , wherein
each of the first light guide, the transparent element and the second light guide is formed of a polymer in which refractive index anisotropy is nearly zero.
18 . A display device comprising:
a liquid crystal panel;
an illumination device which faces the liquid crystal panel; and
an optical sheet provided between the liquid crystal panel and the illumination device, wherein
the illumination device comprises:
a plurality of light sources;
a first light guide which has a first side surface facing the plurality of light sources, and a second side surface on a side opposite to the first side surface;
a second light guide which has a third side surface;
a transparent element which has a first plane being in contact with the second side surface and the third side surface, a second plane located on a side opposite to the first plane and inclining with respect to the first plane, an upper surface located on a side facing the optical sheet between the first plane and the second plane, and a lower surface on a side opposite to the upper surface; and
a reflective element which faces the second plane,
the first light guide is provided between the second light guide and the liquid crystal panel, and
in the transparent element, a width of the lower surface is greater than a width of the upper surface.
19 . The display device of claim 18 , wherein
the first light guide is a glass substrate which has a refractive index distribution for forming a plurality of optical waveguides, and
each of the transparent element and the second light guide is formed of a polymer in which refractive index anisotropy is nearly zero.
20 . The display device of claim 18 , wherein
each of the first light guide, the transparent element and the second light guide is formed of a polymer in which refractive index anisotropy is nearly zero.