Progressive power lens and mold for producing same
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorMoriyasu Shirayanagi
Life of this patent
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Abstract
A progressive power lens has an effective surface including a progressive surface which progressively varies the power, and a peripheral rim surface portion which surrounds the progressive surface yet does not function as an effective surface. The rim surface is curved. The invention is also directed to a mold to produce a progressive power lens. The mold includes a portion which forms progressive surface which progressively varies the power of the lens and a curved rim surface forming portion which forms a rim surface of the lens which does not function as a progressive surface.
Claims21
A progressive power lens having an effective surface, comprising:
- a progressive surface portion which progressively varies a power;
- and
- a peripheral rim surface portion which does not function as a progressive surface portion and which is disposed about at least a portion of said effective surface of said lens, wherein said peripheral rim surface portion is a portion of a symmetrically curved surface, said peripheral rim surface portion having a common sign opposite a sign of said progressive surface portion.
A mold for producing a progressive power lens, said mold comprising a forming portion which forms an effective surface including a progressive surface, which progressively varies a power of the lens, and a curved rim surface forming portion which is a portion of a symmetrically curved surface, which forms a rim of the lens and which does not function as a progressive surface, said curved rim surface forming portion having a common sign opposite a sign of said effective surface.
Dependencies are inferred from the claim text.