| 摘要 |
PROBLEM TO BE SOLVED: To provide a Fresnel lens for a solar system, which is high in light utilization efficiency and excels in performance. SOLUTION: A plurality of prism parts arranged on one surface comprise: prism parts 11 of a first group, located on a side close to an optical axis A; and prism parts 12 of a second group, located on a side far from the optical axis A. The respective prism parts 11 of the first group are formed to perform action of a condenser lens by refracting and emitting light reaching a first surface 3, by the first surface 3. The respective prism parts 12 of the second group are formed to perform action of a condenser lens by totally reflecting the light reaching the first surface 3, by the first surface 3, and then refracting and emitting the light by a second surface 4. The incident surfaces 2 of the respective prism parts 11 and 12 of the first group or the second group are condenser lens surfaces. COPYRIGHT: (C)2011,JPO&INPIT
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