Designing method and designing device for progressive power lens

Patent metadata

Field	Value
Publication number	US-2018149883-A1
Application number	US-201615576266-A
Country	US
Kind code	A1
Filing date	May 26, 2016
Priority date	May 26, 2015
Publication date	May 31, 2018
Grant date	—

Abstract

A vision simulation, on assumption that spectacles are worn, is performed for a first model designed by setting a target additional power of a desirable value at a position corresponding to a fitting point on a principal meridian. A correction amount is computed for correcting the difference between a simulation value obtained for the additional power at the position corresponding to the fitting point on the principal meridian through the vision simulation and the target additional power. A second model is designed by replacing the additional power with a value obtained by the addition of the calculated correction amount to the target additional power.

First claim

1 . A design method for a progressive power lens in which: an intermediate region where an addition power continuously changes is provided between a first region for providing a first power and a second region for providing a second power; a principal meridian is provided in the first region, the intermediate region and the second region; a progression-start point through which the principal meridian passes is set in a portion of the intermediate region adjacent to the first region; a progression-end point through which the principal meridian passes is set in a portion of the intermediate region adjacent to the second region; and a fitting point is set at a position between the progression-start point and the progression-end point, along an extended line of a portion of the principal meridian that passes through the first region, the design method comprising:
a simulation step of performing a vision simulation, on the assumption that spectacles are worn, for a first model designed by setting a desired value of a target addition power at a position corresponding to the fitting point on the principal meridian; a computing step of computing a correction amount for correcting the difference between the target addition power and a simulation value for an addition power at the position corresponding to the fitting point on the principal meridian obtained in the simulation step; and a design step of designing a second model by setting again an addition power, which is obtained by adding the correction amount computed in the computing step to the target addition power, at the position corresponding to the fitting point on the principal meridian.

2 . The design method for a progressive power lens according to claim 1 , wherein
in the simulation step, numeric values of at least one parameter out of the target addition power of the first model, a prescription addition power which is determined by the difference between the first power and the second power, a cylindrical power, a cylindrical axis direction, a prism power, a prism base direction, and a spherical power in a region for providing the first power are changed, and the simulation step is performed a plurality of times, in the computing step, the correction amount is computed for each of the simulations, and in the design step, the addition power at the position corresponding to the fitting point on the principal meridian for designing the second model is set, based on a relationship between the correction amount and at least one of the target addition power, the prescription addition power, the spherical power, the cylindrical power, the cylindrical axis direction, the prism power, and the prism base direction, which are stored in advance.

3 . The design method for a progressive power lens according to claim 1 , further comprising, a determination step of re-performing the simulation on the assumption that spectacles are worn, and determining whether a re-performed simulation value and the desired value coincide, based on the difference between the re-performed simulation value and the desired value, after the design step, wherein
the design step is re-performed when the re-performed simulation value and the desired value are determined not to coincide in the determination step.

4 . The design method for a progressive power lens according to claim 1 , wherein
the fitting point is set at the position between the progression-start point and the progression-end point, along the extended line of a portion of the principal meridian that passes through the first region, and the target addition power is set in accordance with a target distance to a target position which a user desires to clearly see, and an average gradient of an addition power between the progression-start point and the fitting point is set to differ from an average gradient of an addition power between the fitting point and the progression-end point.

5 . A design device for a progressive power lens in which: an intermediate region where an addition power continuously changes is provided between a first region for providing a first power and a second region for providing a second power; a principal meridian is provided in the first region, the intermediate region, and the second region; a progression-start point through which the principal meridian passes is set in a portion of the intermediate region adjacent to the first region; a progression-end point through which the principal meridian passes is set in a portion of the intermediate region adjacent to the second region; and a fitting point is set at a position between the progression-start point and the progression-end point, along an extended line of a portion of the principal meridian that passes through the first region, the design device comprising:
a simulation device that performs a vision simulation, on the assumption that spectacles are worn, for a first model designed by setting a desired value of a target addition power at a position corresponding to the fitting point on the principal meridian, a plurality of times with changing at least one parameter of the target addition power of the first model, a prescription addition power which is determined by the difference between the first power and the second power, a cylindrical power, a cylindrical axis direction, a prism power, a prism base direction, and a spherical power in a region for providing the first power; and a computer that designs the progressive power lens based on a result obtained by the simulation device, wherein the computer comprises: a computing unit that computes, for each simulation, a correction amount for correcting the difference between the target addition power and a simulation value for an addition power at the fitting point, based on information from the simulation device; a storage unit that stores a relationship between the correction amount and at least one of the target addition power, the prescription addition power, the spherical power, the cylindrical power, the cylindrical axis direction, the prism power, and the prism base direction, based on a result computed by the computing unit; an input unit that inputs information of at least one of the target addition power, the prescription addition power, the spherical power, the cylindrical power, the cylindrical axis direction, the prism power, and the prism base direction; a control unit that determines the correction amount for designing a second model according to the information input from the input unit and the information stored in the storage unit; and a design unit that designs the second model by adding the correction amount determined by the control unit to the target addition power and setting again a corrected addition power at the position corresponding to the fitting point on the principal meridian.

Assignees

• Asami Hiroshi
• Ito Ayumu
• Hoya Lens Thailand Ltd

Inventors

• Asami Hiroshi
• Ito Ayumu

Classifications

• G02C7/061

  Spectacle lenses with progressively varying focal power · CPC title

• G06F30/00

  Computer-aided design [CAD] · CPC title

• G02C7/065

  Properties on the principal line · CPC title

• G02C7/06

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

• G02C7/025 Primary

  considering parameters of the viewed object · CPC title