Patent ID: 7270464

Claim:
A back-light device for shedding light on the back of a liquid-crystal panel, the back-light device comprising: a substantially rectangular light-guiding plate, the light-guiding plate including a top surface, a bottom surface, and at least four side surfaces, the at least four side surfaces facing in a direction substantially perpendicular to a direction of a thickness of the light-guiding plate; wherein the at least four side surfaces include an incident surface configured to allow light to enter and a first side surface opposite the incident surface; and wherein one of the top and bottom surfaces of the light-guiding plate is a light-radiating surface; a flexible PCB (printed circuit board) attached to part of the light-guiding plate in a vicinity of the incident surface; a plurality of light sources installed on the flexible PCB, each of the plurality of light sources including a light-radiating surface which contacts the incident surface of the light-guiding plate; and a frame configured to house and hold the light-guiding plate and the flexible PCB, wherein the frame includes a supporting wall configured to support the light-guiding plate, a window provided in the supporting wall and through which the light-radiating surface of the light-guiding plate is seen, and erected walls which are erected at the periphery of the supporting wall; wherein the erected walls include a first erected wall substantially perpendicular to the supporting wall, and a second erected wall substantially perpendicular to the supporting wall and located opposite the first erected wall; wherein the flexible PCB includes a PCB part on which the light sources are installed and erected parts which are erected on the far side of the PCB part away from the incident surface of the light-guiding plate; wherein the light-guiding plate is positioned in the frame such that the first side surface of the light-guiding plate contacts the second erected wall; and wherein the flexible PCB is positioned in the frame such that the erected parts contact the first erected wall of the frame and the flexible PCB biases at least one of the plurality of light sources against the incident surface of the light guiding plate.