| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical element having a simple structure and a plurality of focuses which can be produced at a low cost by forming a resin layer on a part of the one optical face of the base material of an optical element to generate a plurality of focuses. SOLUTION: The base material 11 of an optical element consists of, for example, an optical glass, and is formed into a lens having a desired focus. A resin layer 12 is formed on the optical face of the base material 11 of the optical element. Since the resin layer 12 is present, the focus by the light 13 passing through the base material 11 of the optical element and further through the resin layer 12 is different from the focus by the light 14 passing only through the base material 11 of the optical element, and as a result, the lens shown in the figure has two focuses. As for the base material 11 of the optical element, a crystalline optical material or a polymer optical material may be used as well as the optical glass. By this method, an optical element having a plurality of focuses can be easily obtained even when the face shape of dies to be used are simple planes or spheres.
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