NOVELTY - The apparatus (400) has a display panel comprising microstructures (126, 426), each comprising first structure surface (4262) and second structure surface (4264) that are arranged correspond to one of rows of display units and one of rows of solar cell units. Inclination of the first structure surface makes thicknesses of waveguide plates (120, 420) gradually decrease along upward direction from a ground surface such that direction is perpendicular to the ground surface when the display apparatus is arranged.    USE - Display apparatus for large outdoor billboards and advertising boards.    ADVANTAGE - The waveguide plate is arranged in front part of the display panel, so that amount of external light e.g. solar light, directly irradiating onto the display units is reduced and the amount of external light irradiating onto the solar cell units is increased, thus prolonging the lifetime of LEDs in the display apparatus, and enhancing photovoltaic conversion performance of the solar cell units, and hence reducing power consumption. The apparatus can irradiate the external light onto the waveguide plate along tilting direction, so that possibility of the external light to be subjected to total reflection at the first structure surface is increased and percentage of the external light irradiating onto the display units can be reduced, thus preventing temperature rise of the display units due to the irradiation of the external light, and hence prolonging the lifetime of the apparatus.    DETAILED DESCRIPTION - The display units are selected from one of LED units, electrophoretic display units, electro-wetting display units, LCD units and organic light emitting display units. The second structure surface of microstructures is a rough surface and a curved surface.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a display apparatus.    Waveguide plates (120, 420)    Microstructures (126, 426)    Display apparatus (400)    Optical adhesive (430)    Structure surfaces (4262, 4264)