Patent ID: 8579489

Claim:
An illuminator comprising: a light source unit composed of a point light source; a light guide plate including an incidence surface into which light emitted from the light source unit is introduced, and an exit surface out which the light that has been introduced from the incidence surface exits; a prism body where a plurality of prisms are arranged so as to refract the light that has exited out from the exit surface of the light guide plate, wherein the prism body is arranged at a specific area on the entire exit surface of the light guide plate so as to refract part of the light that has exited out from the exit surface of the light guide plate; and an optical path modification means on a reflection surface facing the exit surface of the light guide plate so that an optical path of the light introduced from the incidence surface of the light guide plate is adapted to direct toward the exit surface of the light guide plate; wherein the optical path modification means is configured so that a luminous intensity distribution of the light emitted from the exit surface of the light guide plate where the prism body is not provided, the optical path of the light being changed by means of the optical path modification means, and a luminous intensity distribution of the light obtainable by which the emitted light is refracted with the prism body have a complementary relation therebetween so as to obtain certain luminous intensity distribution properties.