Patent ID: 8913209

Claim:
A flat panel display device, comprising a backlight system and a display panel, wherein: the backlight system comprises a light source, a light homogenization mechanism, and a back frame; the back frame carries the light source and the light homogenization mechanism, the light homogenization mechanism guiding light from the light source into the display panel; the back frame comprises primary assembling pieces, secondary assembling pieces, and an adjustable bracing piece; the primary assembling pieces have a number of at least two, the at least two primary assembling pieces including a first primary assembling piece comprising joint sections that include at least a first joint section and a second joint section and a second primary assembling piece comprising at least a third joint section, the at least two primary assembling pieces being joined with the joint sections; at least one of the primary assembling pieces comprises a reinforcement structure formed on the joint section thereof; the secondary assembling pieces are joined to the primary assembling pieces; the bracing piece is mounted to the primary assembling pieces or the secondary assembling pieces or mounted to both the primary assembling pieces and the secondary assembling pieces, wherein available mounting points between the bracing piece and the primary assembling pieces or the secondary assembling pieces are of a number of at least two so that the bracing piece is selectively mounted to the back frame at different positions; and the joint section of each of the primary assembling pieces has a cross-section that forms the reinforcement structure, the cross-section comprising a projection formed on a surface of each of the primary assembling pieces and a recess formed in an opposite surface of each of the primary assembling pieces to correspond to the projection, whereby the first and second primary assembling pieces are positioned with respect to each other in a recess-projection paired form, where the projection of one of the first and second primary assembling pieces is removably received in and in snug and releasable engagement with the recess of the other one of the first and second primary assembling pieces, wherein the third joint section of the second primary assembling piece is switchably connected to and occupying one of the first and second joint sections of the first primary assembling piece, while the other one of the first and second joint sections of the first primary assembling piece being idle and free of occupation, so as to respectively define a first size and a second size of the back frame, the second size being different from the first size.