| 摘要 |
PROBLEM TO BE SOLVED: To provide a spectacle lens which is suitable for observing an object in a middle distance and has the region of a wide clear vision range. SOLUTION: The spectacle lens has a constant refractive power region of which the transmission refractive power is approximately constant in the approximately center part of a lens, an upper refractive power gradient region where the transmission refractive power changes continuously to the upper end of the lens on the upper part of the constant refractive power region, a down refractive power gradient region where the transmission refractive power changes continuously to the lower end of the lens on the lower part of the constant refractive power region, and the constant refractive power region is a region for object observation in the middle distance. COPYRIGHT: (C)2004,JPO
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