| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical element excellent in scratch resistance which is less likely to be scratched even if sand particles collide in a situation of strong wind speed.SOLUTION: In an optical element 4 for condensing sun light including a translucent substrate 5 composed of an organic resin and having a planar first surface on which sun light impinges, and a planar second surface from which sun light is emitted, a thin film layer 7 of different composition from the translucent substrate 5 formed on the first surface thereof, and a Fresnel lens element 6 formed on the second surface of the translucent substrate 5, and making a solar cell element 2 condense sun light, the thin film layer 7 contains 80 mass% or more of inorganic components, and has a thickness of 0.5-3.0 μm.SELECTED DRAWING: Figure 1 |
