| 摘要 |
A front luminance of light emitted from a surface light emitting apparatus having a surface light emitting element is greatly improved. The surface light emitting apparatus is provided with a surface light emitting element (20) and a photochromic sheet (10). A repeated uneven pattern having a cross section in a trapezoidal shape is arranged at least on one side of the photochromic sheet, a flat portion (12a) at the tip on the protruding side of the unevenness is adhered to an emitting surface (21a) of the surface light emitting element, and conditions of 0.75>D>4[(sin &thetas;−1/n)2+0.034] are met, where, &thetas; is an apex angle formed by facing inclined surfaces protruded in a trapezoidal shape of the photochromic sheet, n is a refractive index of the photochromic sheet, and D is a ratio of the length of the surface light emitting element at a portion adhered to the emitting surface to the length of at least one cycle of the unevenness in an arrangement direction.
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