Abstract: Included are a rectangular frame body 10, a box-shaped light reflection enclosure 20 which is disposed to enclose one side of the frame body 10 and which has an inner surface of a light reflection surface 21, a translucent light diffusion film 30 disposed to enclose the other side of the frame body 10, and a linear LED array member 40 having multiple light emitting diodes 42 aligned at predetermined intervals. The LED array member 40 is disposed along at least one edge of the frame body 10. The light emitting diodes 42 emit light to the light reflection surface 21.