Progressive refractive power lens
First Claim
1. A progressive-power lens comprising a distance portion, a near portion and an intermediate portion, wherein an object-side refractive surface is formed from a part of an aspherical surface symmetric with respect to a rotational axis and an eyeball-side refractive surface is from a progressive surface;
- characterized in that there is a relationship shown below between a curvature C1 at a distance reference point of the object-side refractive surface and a curvature C2 at a near reference point of the object-side refractive surface;
C1<
C2.
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Accused Products
Abstract
It has been difficult to manufacture an inside surface progressive-power lens which is as thin as an outside surface progressive-power lens due to a limited configuration of an object-side refractive surface of the inside surface progressive-power lens. However, a thin progressive-power lens with less blur and distortion can be provided at a reduced cost by forming its object-side refractive surface from an aspherical surface which is symmetric with respect to a rotational axis and has a smaller curvature at a distance reference point than that at a near reference point, and by forming an eyeball-side refractive surface from a combination of a progressive surface, an astigmatic refraction surface and an “as-worn” corrective aspherical surface.
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Citations
24 Claims
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1. A progressive-power lens comprising a distance portion, a near portion and an intermediate portion, wherein an object-side refractive surface is formed from a part of an aspherical surface symmetric with respect to a rotational axis and an eyeball-side refractive surface is from a progressive surface;
- characterized in that there is a relationship shown below between a curvature C1 at a distance reference point of the object-side refractive surface and a curvature C2 at a near reference point of the object-side refractive surface;
C1<
C2. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
- characterized in that there is a relationship shown below between a curvature C1 at a distance reference point of the object-side refractive surface and a curvature C2 at a near reference point of the object-side refractive surface;
Specification