BACK LIGHT DEVICE AND DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To enhance the efficiency of the light utilization efficiency of a back light device and a display device. SOLUTION: This back light device generates back light by a light source 1, a means for introducing the light radiated from this light source 1 onto a two-dimensional plane and a means for radiating the light introduced onto this two-dimensional plane in the normal direction of the two-dimensional plane. The back light device has a plurality of optical fibers 3 consisting of cores and clads lined up in parallel on the two-dimensional plane, a coupling means 8 for coupling the light radiated from the light source 1 to the one-side ends of the respective optical fibers 3 and a mirror 2 disposed in correspondence to the peripheral surfaces of the optical fibers 3 exclusive of the surfaces to radiate the light toward the side on the two-dimensional plane and part or the whole of the other-side end faces. The back light is generated by the light 4 leaking from the outside surface of the clads of the respective optical fibers 3. The varying magnitude of the intensity of the light 4 radiated from the clad surfaces of the optical fibers 3 may be changed by changing the diameters of the cores, the thicknesses of the cores and the refractive indices of the cores and the clads.