Display device

1. A display device comprising:

a liquid crystal display panel comprising a display surface and a back surface opposite to the display surface; and

a backlight device comprising a light guide plate including a first main surface opposed to the back surface of the liquid crystal display panel, a second main surface opposite to the first main surface, and end surfaces connecting the first main surface and the second main surface and including an end surface constituting a light incident surface, and light sources opposed to the light incident surface, wherein

the light guide plate comprises divided light guide plates, each comprising the first main surface, the second main surface, the light incident surface, and side surfaces cross to the first main surface and the light incident surface; and an adhesive member connecting the side surfaces of the divided light guide plates to each other and having optical properties different from optical properties of the divided light guide plates,

the first main surface includes a plurality of projection streaks extending in a traveling direction of light entering from the light incident surface, and

a cross-section of each of the projection streaks has a truncated semicircle shape which is formed of a plurality of circular arcs arranged in a width direction of the projection streak.

2. The display device of claim 1 , wherein

a refractive index of the adhesive member is different from a refractive index of the divided light guide plates.

3. The display device of claim 2 , wherein

the refractive index of the adhesive member is less than the refractive index of the divided light guide plates.

4. The display device of claim 1 , wherein

the backlight device comprises light sources opposed respectively to the light incident surfaces of the divided light guide plates.

5. The display device of claim 1 , wherein

the light guide plate includes a second recess/projection pattern on the second main surface,

the second recess/projection pattern includes dot-shaped or dome-shaped second projections on the second main surface, and

in each of the divided light guide plates, a pattern arrangement density of the second projections increases from the light incident surface side in the first direction orthogonal to the light incident surface.

6. The display device of claim 5 , wherein

in each of the divided light guide plates, the pattern arrangement density of the second recess/projection patterns varies in a second direction orthogonal to the first direction.

7. The display device of claim 1 , wherein

the light guide plate comprises four divided light guide plates, each comprising the first main surface, the second main surface, the light incident surface, and side surfaces orthogonal to the first main surface and the light incident surface, and an adhesive member connecting the side surfaces of the divided light guide plates to each other and having optical properties different from optical properties of the divided light guide plates, and

the backlight device comprises light sources respectively opposed to the light incident surfaces of the four divided light guide plates.

8. A display device comprising:

a liquid crystal display panel; and

a backlight device illuminating the liquid crystal display panel with light, wherein

the backlight device comprises a light source and light guide plates,

each of the light guide plates comprises a first main surface, a second main surface opposed to the first main surface, and side surfaces between the first main surface and the second main surface, one of the side surfaces constituting a light incident surface opposed to the light source,

the adjacent two light guide plates are arranged such that the side surfaces are opposed to each other and the two opposed side surfaces are attached to each other with an adhesive member,

a refractive index of the adhesive member is less than a refractive index of the light guide plates,

the first main surface includes a plurality of projection streaks extending in a traveling direction of light entering from the light incident surface, and

a cross-section of each of the projection streaks has a truncated semicircle shape which is formed of a plurality of circular arcs arranged in a width direction of the projection streak.

9. The display device of claim 8 , wherein

each of the light guide plates comprises one side surface constituting a light incident surface, which is not attached to the adhesive member, and

light emitted from the light source enters the light guide plates from the light incident surfaces.

10. A display device comprising:

a liquid crystal display panel; and

a backlight device illuminating the liquid crystal display panel with light, wherein

the backlight device comprises a light source and light guide plates,

each of the light guide plates comprises a rectangular first main surface, a second main surface opposed to the first main surface, and side surfaces connecting the first main surface and the second main surface, one of the side surfaces constituting a light incident surface opposed to the light source,

the first main surface includes a pair of long sides opposed to each other and a pair of short sides opposed to each other,

the light guide plates are joined to one another such that side surfaces along the long sides of adjacent light guide plates are adhered to each other with an adhesive member,

the adhesive member has a refractive index less than a refractive index of the light guide plates,

the first main surface includes a plurality of projection streaks extending in a traveling direction of light entering from the light incident surface, and

a cross-section of each of the projection streaks has a truncated semicircle shape which is formed of a plurality of circular arcs arranged in a width direction of the projection streak.

11. The display device of claim 10 , wherein

the light guide plates comprise side surfaces along the short sides which are not attached to each other with the adhesive member as light incident surfaces, and

light emitted from the light source enters the light guide plates from the light incident surfaces.