Patent ID: 8334942

Claim:
A backlight device comprising: a light emitting diode as a light source assembled into a concave portion of a light-guiding plate such that the light emitting diode is contained within the concave portion, wherein an upper portion of the concave portion is formed to have a cylindrical shape, wherein a lower portion of the concave portion is formed to have a shape of an inclined or curved surface that has an angle except a right angle with respect to the a bottom surface of the light guiding plate that faces a light-emitting surface of the light guiding plate, the lower portion positioned on the bottom surface of the light-guiding plate and opposite to the light-emitting surface, and the lower portion having a width that gradually increases in a direction away from the upper portion so as to be wider than a diameter of the cylindrical upper portion, and wherein the light-guiding plate includes a diffusion reflection structure portion provided in contact with the light emitting diode and the bottom surface, that faces a light-emitting surface of the light-guiding plate and a reflection structure portion provided on a side surface of the light-guiding plate.