To eliminate an unevenness of luminance, and to manufacture a large screen for a picture display device with an upconversion system.

Two or more exciting light rays are introduced from a direction which is almost orthogonal to a panel surface to a display panel containing a luminescent material which emits light by two-photon excitation, and the luminescent material emits light. As for exciting light, for example, two or more infrared-laser lights are radiated. The luminescent material which emits light by two-photon excitation is, for example, a rare earth ion. In order to introduce exciting light from the direction which is almost orthogonal to the panel surface, opposing to the display panel, a light transmission plate or a thin prism is installed. A light guide means which guides exciting light, such as a Fresnel lens, an optical waveguide, or an optical fiber is formed on an end surface of the light transmission plate or the thin prism.