LIGHT GUIDE BODY, LIGHT SOURCE FOR ILLUMINATION, AND LIGHTING SYSTEM

PROBLEM TO BE SOLVED: To restrain irregular light scattering from occurring at edges a light guide body has on its side face, as light is incident from end faces and emitted from the side face.SOLUTION: The lighting system is provided with a light source for illumination 11. The light source for illumination 11 is equipped with an LED module 20 each at either end in a length direction having at least one LED 21 mounted on a board, and is further equipped with a longitudinally long light guide body 30 formed in a plate shape and curved in a length direction. The light guide body 30 is provided with an end face 31 at one end in a length direction, an end face 32 at the other end in a length direction, and a side face 33 with edges 34 extended in a length direction. An area away from the edges 34 by a given distance is to be a diffusion area 35 on the side face 33. The light guide body 30 has light emitted by the LEDs 21 incident from the end faces 31, 32, and has it diffused with a diffusion pattern 36 formed at the diffusion area 35. Then, light diffused with the diffusion pattern 36 is made emitted from an emission area 37.