| 摘要 |
PROBLEM TO BE SOLVED: To efficiently emit light radiated from a illuminant to the outside. SOLUTION: An organic EL element is formed by stacking a transparent electrode 11, an organic EL layer 12, and a reflecting electrode 13 on one side of a glass substrate 10 in order. A diffusion plate 16 whose surface is formed in fine irregular shape is installed on the other side of the glass substrate 10 through an optical oil 15 whose light refractive index is higher than that of air. Light is refracted on the interface of each constituting element and goes ahead. Since the light refractive index of the optical oil 15 is higher than that of glass substrate 10, the total reflection critical angle of light is made larger than the case where the glass substrate 10 comes in contact with air, and a rate of light outgoing from the glass substrate 10 is increased. Since the angle of light can variously be changed on the diffusion plate 16, light to be emitted from the end surface of the glass substrate 10 by the relation of the refractive index of each constituting element if the diffusion plate 16 is absent is reflected on the reflective electrode 13 and can be emitted to the outside.
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