Spectacle lens, method for designing spectacle lens, and method for manufacturing spectacle lens

Patent metadata

Field	Value
Publication number	US-11391968-B2
Application number	US-201716307455-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

A spectacle lens including a prism prescription that has an eyeball-side optical surface. When one side is the same side as a prism base direction (nose side) and the other side is an opposite side of the prism base direction with a direction orthogonal to the prism base direction passing through a prism measurement reference point as a boundary, a minimum value of a curvature of the eyeball-side optical surface is on the same side as the prism base direction (nose side). Since a mean curvature becomes smaller in the prism base direction than a mean curvature of the prism measurement reference point and becomes larger in the opposite direction than the mean curvature of the prism measurement reference point across the prism measurement reference point, deviation in line of sight between right and left eyes is resolved.

First claim

The invention claimed is:

1. A method for designing a spectacle lens including a prism prescription, the lens including a prism for correction of fixation disparity or heterophoria, wherein
a lens to which a prism corresponding to the prism prescription is added is a prism prescription lens,
a lens which has a same prescription value other than the prism prescription and to which the prism is not added is a reference lens,
among rays that are emitted from a plurality of object points, incident on an object-side optical surface of the reference lens and emitted from an eyeball-side optical surface of the reference lens, in respective rays obtained by rotating a plurality of rays directed toward an eyeball rotation point around the eyeball rotation point by an angle corresponding to the prism prescription applied to a prism measurement reference point, incident ray vectors incident on the object-side optical surface constitute a target ray group, and
among rays that are emitted from the plurality of object points, incident on an object-side optical surface of the prism prescription lens and emitted from an eyeball-side optical surface of the prism prescription lens, in a plurality of rays directed toward the eyeball rotation point, incident ray vectors incident on the object-side optical surface constitute a prism ray group,
the method comprising:
a prism prescription lens vector storage step of storing the incident ray vectors constituting the prism ray group and outgoing ray vectors corresponding to the incident ray vectors;
a target ray group storage step of generating, by simulation, the respective rays obtained by rotating the plurality of rays directed toward the eyeball rotation point around the eyeball rotation point by the angle corresponding to the prism prescription applied to the prism measurement reference point, among the rays that are emitted from the plurality of object points, are incident on the object-side optical surface of the reference lens, and are emitted from the eyeball-side optical surface of the reference lens, and storing the incident ray vectors constituting the target ray group and outgoing ray vectors corresponding to the incident ray vectors;
an uncorrected prismatic effect calculation step of calculating a prismatic effect of the prism prescription lens before correction using the incident ray vectors and the outgoing ray vectors stored in the prism prescription lens vector storage step;
an ideal prismatic effect calculation step of calculating a prismatic effect to obtain an ideal outgoing ray with which each angle formed between directions of the outgoing ray vectors emitted from the reference lens and directions of the outgoing ray vectors emitted from the prism prescription lens becomes a constant angle;
a correction prism amount calculation step of calculating a correction prism amount to correct the eyeball-side optical surface of the prism prescription lens based on a difference between the prismatic effect obtained in the uncorrected 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 of the prism prescription lens based on the correction prism amount obtained in the correction prism amount calculation step.

2. The method for designing a spectacle lens according to claim 1 , wherein
the prism prescription lens vector storage step, the uncorrected prismatic effect calculation step, and the correction prism amount calculation step are performed after the correction step, it is determined whether the difference between the prismatic effects is equal to or smaller than a target value or a predetermined number of corrections have been performed, and the correction step is ended if the difference between the prismatic effects is equal to or smaller than the target value or the predetermined number of corrections have been performed.

3. A spectacle lens producing method comprising:
a spectacle lens designing step of designing a spectacle lens including a prism for correction of fixation disparity or heterophoria; and
a processing step of processing the spectacle lens designed in the spectacle lens designing step, wherein
a lens to which the prism corresponding to a prism prescription is added is a prism prescription lens,
a lens which has a same prescription value other than the prism prescription and to which the prism is not added is a reference lens,
among rays that are emitted from a plurality of object points, incident on an object-side optical surface of the reference lens and emitted from an eyeball-side optical surface of the reference lens, in respective rays obtained by rotating a plurality of rays directed toward an eyeball rotation point around the eyeball rotation point by an angle corresponding to the prism prescription applied to a prism measurement reference point, incident ray vectors incident on the object-side optical surface constitute a target ray group, and
among rays that are emitted from the plurality of object points, incident on an object-side optical surface of the prism prescription lens and emitted from an eyeball-side optical surface of the prism prescription lens, in a plurality of rays directed toward the eyeball rotation point, incident ray vectors incident on the object-side optical surface constitute a prism ray group, and
the spectacle lens designing step comprises:
a prism prescription lens vector storage step of storing the incident ray vectors constituting the prism ray group and outgoing ray vectors corresponding to the incident ray vectors;
a target ray group storage step of generating, by simulation, the respective rays obtained by rotating the plurality of rays directed toward the eyeball rotation point around the eyeball rotation point by the angle corresponding to the prism prescription applied to the prism measurement reference point, among the rays that are emitted from the plurality of object points, incident on the object-side optical surface of the reference lens and emitted from the eyeball-side optical surface of the reference lens, and storing the incident ray vectors constituting the target ray group and outgoing ray vectors corresponding to the incident ray vectors;
an uncorrected prismatic effect calculation step of calculating a prismatic effect of the prism prescription lens before correction using the incident ray vectors and the outgoing ray vectors stored in the prism prescription lens vector storage step;
an ideal prismatic effect calculation step of calculating a prismatic effect to obtain an ideal outgoing ray with which each angle formed between directions of the outgoing ray vectors emitted from the reference lens and directions of the outgoing ray vectors emitted from the prism prescription lens becomes a constant angle;
a correction prism amount calculation step of calculating a correction prism amount to correct the eyeball-side optical surface of the prism prescription lens based on a difference between the prismatic effect obtained in the uncorrected 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 of the prism prescription lens 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

• G02C7/061

  Spectacle lenses with progressively varying focal power · CPC title

• G02C7/024 Primary

  Methods of designing ophthalmic lenses · CPC title

• G02C7/14 Primary

  Mirrors; Prisms · CPC title

• G02C7/027

  considering wearer's parameters · CPC title

• G02C7/02

  Lenses; Lens systems {; Methods of designing lenses} · CPC title