An optical member includes a light guide plate having a top surface, a bottom surface, and side surfaces that connect the top surface and the bottom surface three-dimensionally and have a smaller area than the top surface and the bottom surface, a low refractive layer disposed on a side surface of the light guide plate and having a lower refractive layer than the light guide plate, and a wavelength conversion layer disposed on the low refractive layer, the wavelength conversion layer receiving first wavelength light and converting the first wavelength light into second wavelength light, which is of a different wavelength band from the first wavelength light.