NOVELTY - The illumination device comprises a light-pervious substrate (31) having a bottom surface (310), a light incident surface (312) adjacent to the bottom surface and a light emitting surface (314) opposite to the bottom surface, a solid-state light source such as a LED arranged on the light incident surface for emitting light into the substrate through the light incident surface, and thin film solar cells (35) arranged on the bottom surface of the substrate to absorb and convert solar energy into electric energy and supply the electric energy to the solid-state light source.    USE - The illumination device is useful as a window of a building.    ADVANTAGE - The illumination device allows total transmission of light through the substrate by forming solar cells at the spaces, decreases reflection of light on the light emitting surface by provision of the bright enhancement of the light emitting surface thus increasing natural lighting indoors, and provides waterproof and dustproof functions by forming the solid-state light sources and the solar cell as a protective film.    DETAILED DESCRIPTION - The illumination device comprises a light-pervious substrate (31) having a bottom surface (310), a light incident surface (312) adjacent to the bottom surface and a light emitting surface (314) opposite to the bottom surface, a solid-state light source such as a LED arranged on the light incident surface for emitting light into the substrate through the light incident surface, and thin film solar cells (35) arranged on the bottom surface of the substrate to absorb and convert solar energy into electric energy and supply the electric energy to the solid-state light source. A recess is defined in the light incident surface of the substrate for receiving the solid-state light source. The solar cells have a thickness of less than 300 mu m, and are spaced from each other. Spaces are defined between each two solar cells. The grooves are defined in the light emitting surface spatially corresponding to the spaces. Another light source is arranged on inner side walls of the substrate in the grooves. The solar cell comprises spaced silicon spheres. A transparent conductive film is arranged on the bottom surface to fix the solar cell to the substrate.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of an illumination device.    Light-pervious substrate (31)    Solar cell (35)    Bottom surface (310)    Light incident surface (312)    Light emitting surface. (314)