Patent ID: 7724316

Claim:
A backlight device comprising: a light source; supporting means having four edges arranged in a frame-like manner; at least one optical sheet shiftably supported by the supporting means and allowing light emitted from the light source to pass therethrough and be incident on a back surface of a liquid crystal panel, the optical sheet having an opening in a position substantially dividing a length of a bottom edge thereof into halves, the bottom edge being in contact with the supporting means, and the opening having a first diameter; and a vibration-proof member extending through the opening and fixed to the supporting means, the vibration-proof member including a pin having a second diameter, substantially smaller than the first diameter, wherein: the at least one optical sheet is shiftable within a range corresponding to the difference between the first diameter and the second diameter; and when the at least one optical sheet is not subjected to vibrations and is positioned to stand upright, substantially no force is applied to the opening.