The present invention relates to a transformer. In the transformer, secondary winding sections are placed in both sides of a primary winding section, all terminals of the secondary winding sections are used as output terminals, and an input terminal is placed in the opposite side to the output terminals. Therefore, a return wire in the high-voltage output side does not need to be provided, and a sufficient insulation separation distance is secured in the relation with a printed circuit board, which makes it easy to implement a circuit. Further, improved efficiency is obtained over a conventional transformer, there is a significant reduction in cost, and products using the transformer can be small in size. The transformer includes a bobbin composed of one primary winding section having one input terminal and one ground terminal and 2n (n: positive number) secondary winding sections, each secondary winding section having two output terminals; a primary coil wound around the primary winding section; secondary coils wound around the 2n secondary winding sections; and a pair of cores that are respectively inserted into an insertion hole formed inside the bobbin.
A backlight device includes a frame, at least one lamp unit each comprising a transformer and a discharge lamp structured into an integral and rigid unit, and also includes a circuit board for lighting the discharge lamp, which is disposed at the back surface of the frame and at which the transformer is mounted at. The transformer of the lamp unit includes: two terminal blocks having terminal pins; a bobbin having a primary winding and first and second secondary windings wound around an outer circumference of the winding core member; a magnetic core; and two lamp connecting terminals attached respectively to the terminal blocks and connected respectively to the first and second secondary windings, wherein the discharge lamp is attached to the transformer with electrodes of the discharge lamp connected directly to the lamp connecting terminals of the transformer, thus forming the lamp unit into a integral structure.
