Back frame and backlight system

A back frame of a flat panel display device, wherein:

• the back frame comprises primary assembling pieces, secondary assembling pieces, and a bracing piece for fixing a circuit board having at least one major surface defining a normal direction;
• the primary assembling pieces have a number of at least two, the at least two primary assembling pieces being connected through joining, the secondary assembling pieces being joined to the primary assembling pieces;
• the bracing piece comprises a bracing body, a first suspension section and a second suspension section, a first bearing section and a second bearing section, and a first resilient bent section and a second resilient bent section, the bracing body being 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 body 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 first suspension section and second suspension section extend from the bracing body toward one side of the bracing body to be spaced from and opposing each other so as to define therebetween a receiving space for receiving the circuit board therein in such a way that the first and second suspension sections respectively engage first and second opposite side edges of the circuit board by having the circuit board moved into the space in a predetermined direction substantially parallel to the normal direction of the circuit board, the first bearing section and second bearing section being spaced from the bracing body and respectively extending from the first suspension section and the second suspension section to collectively receive the circuit board to be positioned thereon, the first resilient bent section and the second resilient bent section being respectively located between the first and second bearing sections and the bracing body and being respectively bent from the first and second suspension sections toward each other to define a passage having a size smaller than the receiving space, whereby when the circuit board is moved in the predetermined direction substantially parallel to the normal direction of the circuit board to reach and be positioned on the first and second bearing sections, the first bearing section and the first resilient bent section resiliently clamp the first side edge of the circuit board and the second bearing section and the second resilient bent section resiliently clamp the second side edge of the circuit board so as to clamp the circuit board between the first and second suspension sections of the bracing piece.