Eyeglass lens, method for designing eyeglass lens, and method for manufacturing eyeglass lens

Patent metadata

Field	Value
Publication number	US-11391966-B2
Application number	US-201716307458-A
Country	US
Kind code	B2
Filing date	Jun 6, 2017
Priority date	Jun 6, 2016
Publication date	Jul 19, 2022
Grant date	Jul 19, 2022

Abstract

In a spectacle lens added with prism thinning, a spherical refractive power of a first refractive portion is positive, and a prism base direction of a prism provided at a prism measurement reference point is set toward a second refractive portion side; a mean value of a difference of a mean curvature in a lens curved surface along a direction passing through a midpoint of a connecting line between two alignment reference marks and orthogonal to the connecting line with respect to a mean curvature in a lens curved surface along a direction of a lens without prism is smaller in a first-refractive-portion-side region from a fitting point than that in a second-refractive-portion-side region from the fitting point.

First claim

The invention claimed is:

1. A designing method for a spectacle lens comprising a first refractive portion having a first refractive power, a second refractive portion having a second refractive power larger than the first refractive power, and a corridor provided between the first refractive portion and the second refractive portion, the spectacle lens being added with prism thinning, the designing method comprising a lens-surface-shape determination step, wherein
a prism thinning lens is a lens defined by adding a prism in a vertical direction corresponding to an amount of the prism thinning to a reference lens designed in accordance with a prescription value, the prism thinning lens comprising minimum edge thicknesses of an upper end and a lower end,
among rays that are emitted from a plurality of object points, are incident on an object-side optical surface of the reference lens and exit from an eyeball-side optical surface of the reference lens, rays that are obtained by rotating a plurality of rays directed toward an eyeball rotation point around the eyeball rotation point by an angle corresponding to a prism amount of the prism thinning applied at a prism measurement reference point of the reference lens and respectively comprise incident ray vectors incident on the object-side optical surface and exit ray vectors exiting from the eyeball-side optical surface are defined as a target ray group, and
among rays that are emitted from the plurality of object points, are incident on an object-side optical surface of the prism thinning lens; and exit from an eyeball-side optical surface of the prism thinning lens, rays that are directed toward the eyeball rotation point and respectively comprise incident ray vectors incident on the object-side optical surface and exit ray vectors exiting from the eyeball-side optical surface are defined as a prism ray group,
the method comprising:
a prism-thinning-lens vector storing step of storing the prism ray group;
a target-ray-group storing step of storing the target ray group;
a pre-correction prismatic effect calculation step of calculating a prismatic effect of the prism thinning lens before correction from the prism ray group stored in the prism-thinning-lens vector storing step;
an ideal prismatic effect calculation step of calculating an ideal prismatic effect in which angles respectively formed by directions of the exit ray vectors exiting from the reference lens and directions of the exit ray vectors exiting from the prism thinning lens are at minimum at any given point, from the exit ray vectors of the prism ray group stored in the prism-thinning-lens vector storing step and the exit ray vectors of the target ray group stored in the target-ray-group storing step;
a correction prism amount calculation step of calculating a correction prism amount to correct a slope of the eyeball-side optical surface of the prism thinning lens based on a difference between the prismatic effect obtained in the pre-correction prismatic effect calculation step and the prismatic effect obtained in the ideal prismatic effect calculation step; and
a correction step of correcting the eyeball-side optical surface based on the correction prism amount obtained in the correction prism amount calculation step.

2. The designing method for the spectacle lens according to claim 1 , wherein
after the correction step, the prism-thinning-lens vector storing step, the pre-correction prismatic effect calculation step, and the correction prism amount calculation step are performed; determination is made as to whether or not a difference of the prismatic effect is equal to or less than a target value, or a predetermined number of corrections have been performed; and the correction step is terminated when a difference of the prismatic effect is equal to or less than a target value, or a predetermined number of corrections have been performed.

3. A producing method for a spectacle lens, the producing method comprising: a spectacle lens designing step; and a processing step of processing a spectacle lens designed in the spectacle lens designing step, wherein
the spectacle lens designing step is a step of designing a spectacle lens comprising a first refractive portion having a first refractive power, a second refractive portion having a second refractive power larger than the first refractive power, and a corridor provided between the first refractive portion and the second refractive portion, the spectacle lens being added with prism thinning,
a prism thinning lens is defined by adding a prism in a vertical direction corresponding to an amount of the prism thinning to a reference lens designed in accordance with a prescription value, the prism thinning lens comprising minimum edge thicknesses of an upper end and a lower end,
among rays that are emitted from a plurality of object points, are incident on an object-side optical surface of the reference lens and exit from an eyeball-side optical surface of the reference lens, rays that are obtained by rotating a plurality of rays directed toward an eyeball rotation point around the eyeball rotation point by an angle corresponding to a prism amount of the prism thinning applied at a prism measurement reference point of the reference lens and respectively comprise incident ray vectors incident on the object-side optical surface and exit ray vectors exiting from the eyeball-side optical surface are defined as a target ray group, and
among rays that are emitted from the plurality of object points, are incident on an object-side optical surface of the prism thinning lens and exit from an eyeball-side optical surface of the prism thinning lens, rays that are directed toward the eyeball rotation point and respectively comprise incident ray vectors incident on the object-side optical surface and exit ray vectors exiting from the eyeball-side optical surface are defined as a prism ray group,
the method comprising:
a prism-thinning-lens vector storing step of storing the prism ray group;
a target-ray-group storing step of storing the target ray group;
a pre-correction prismatic effect calculation step of calculating a prismatic effect of the prism thinning lens before correction from the prism ray group stored in the prism-thinning-lens vector storing step;
an ideal prismatic effect calculation step of calculating an ideal prismatic effect in which angles respectively formed by directions of the exit ray vectors exiting from the reference lens and directions of the exit ray vectors exiting from the prism thinning lens are at minimum at any given point, from the exit ray vectors of the prism ray group stored in the prism-thinning-lens vector storing step and the exit ray vectors of the target ray group stored in the target-ray-group storing step;
a correction prism amount calculation step of calculating a correction prism amount to correct a slope of the eyeball-side optical surface of the prism thinning lens based on a difference between the prismatic effect obtained in the pre-correction prismatic effect calculation step and the prismatic effect obtained in the ideal prismatic effect calculation step; and
a correction step of correcting the eyeball-side optical surface based on the correction prism amount obtained in the correction prism amount calculation step.

Assignees

• Hoya Lens Thailand Ltd

Inventors

• Hatanaka Takashi
• Odaira Tomohiro

Classifications

• G02C7/022

  Ophthalmic lenses having special refractive features achieved by special materials or material structures (G02C7/049 takes precedence) · CPC title

• G02C7/14

  Mirrors; Prisms · CPC title

• G02C7/061 Primary

  Spectacle lenses with progressively varying focal power · CPC title

• G02C7/024

  Methods of designing ophthalmic lenses · CPC title

• G02C7/06 Primary

  bifocal; multifocal {; progressive (G02C7/041 takes precedence)} · CPC title