Light guide member, flat light source device, and display device

A light guide member, a flat light source device and a display device using the light guide member. A plurality of luminescent devices that emit light of violet to blue color are arrayed on a substrate, and a light guide member is disposed upward thereof that includes a first area that consists of a transparent resin and composed of the resin independently, a second area in which there is dissolved in the resin a luminescent substance that generates a second color having a radiation peak wavelength at a wavelength different from a radiation peak wavelength of a luminescent device of the first color, and a third area in which there is dissolved in the resin a luminescent substance that generates a third color having a radiation peak wavelength at a wavelength different from the radiation peak wavelengths of luminescent devices of the first and second colors.