| 摘要 |
PURPOSE:To continue a visual field extending from a distant part to a near part, and also, to reduce the aberration by placing two progressive multifocus lenses in which codes of a joining degree are different, along the optical axis. CONSTITUTION:Main meridians M1, M2 of two progressive multifocus lenses 1, 2 are on the same plane, and allowed to cross vertically an optical axis OA. In such a case, a joining degree of the lens 1 is 2 diopters (D), and that of the lens 2 is -2D, therefore, a variation of the refracting power is offset and becomes instant by said arrangement. Accordingly, when the lenses 1, 2 are used jointly, there is the same effect as a single focus lens of 2D is installed and used, and when it is installed and used by removing the lens 2, a continuous visual field extending from a distant part to a near part is obtained. Also, when the lens 1 is made movable in the vertical direction, and the lenses 1, 2 are shifted relatively, the focus can be adjusted freely extending from a distant part to a near part.
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