Patent ID: 8089582

Claim:
A liquid crystal display device comprising: a liquid crystal panel; a light guide plate having side surfaces, the side surfaces including non-adjacent opposite side surfaces, the light guide plate being mounted on a rear surface of the liquid crystal panel; at least one light source positioned with respect to at least one of the non-adjacent opposite side surfaces of the light guide plate so that a light ray therefrom is incident on the light guide plate at an incidence plane formed on the at least one of the non-adjacent opposite side surfaces of the light guide plate; and light source driving means for driving the at least one light source; wherein the light guide plate guides the light ray incident from the incidence plane, outputs the light ray from an output plane of the light guide plate facing the liquid crystal panel, and illuminates the liquid crystal panel from the rear surface of the liquid crystal panel; wherein at least one groove is formed on a plane of the light guide plate which extends substantially parallel to the rear surface of the liquid crystal panel, the at least one groove having a depth in a direction from the output plane of the light guide plate to a back surface of the light guide plate which is opposite to the output plane without penetrating one of the output plane and the back surface of the light guide plate the direction of the depth thereof; wherein the at least one groove extends between the non-adjacent opposite side surfaces of the light guide plate, the at least one groove having an end portion thereof which stops short of the non-adjacent opposite side surfaces without penetrating the non-adjacent opposite side surfaces, at least one of the non-adjacent opposite side surfaces having the at least one light source positioned with respect thereto; wherein the plane on which the at least one groove is formed has an indented portion and raised portions, the raised portions being higher than the indented portion, the indented portion being interposed between the raised portions, the raised portions extending to reach a part of the peripheries of the plane at both of the non-adjacent opposite side surfaces; wherein the at least one groove extends in a direction perpendicular to the non-adjacent opposite side surfaces.