Progressive addition lens

• US 10,642,070 B2
• Filed: 06/03/2015
• Issued: 05/05/2020
• Est. Priority Date: 06/04/2014
• Status: Active Grant

• Current Assignee: Hoya Lens Thailand Limited (Hoya Corporation)
• Original Assignee: Hoya Lens Thailand Limited (Hoya Corporation)
• Inventors: Kaga, Tadashi, Shinohara, Toshihide, Ito, Ayumu, Asami, Hiroshi
• Primary Examiner(s): Pasko, Nicholas R.
• Application Number:
  US15/311,358
• Publication Number:
  US 20170115510A1
• Time in Patent Office: 1,798 Days
• Field of Search: 35115906, 3511591, 35115911, 35115912, 35115913, 35115914, 35115915
• CPC Class Codes: G02C 7/06 bifocal; multifocal ; progressive G02C7/041 takes precedence
• CPC Class Codes: G02C 7/066 Shape, location or size of the viewing zones
• CPC Class Codes: G02C 7/068 Special properties achieved by the combination of the front and back surfaces

Abstract

Progressive addition lens includes a near portion having a power for viewing a near field, a distance portion having a power for viewing a distance field further than the near field, and an intermediate portion connecting the distance portion and the near portion. The progressive addition lens includes an aspherical object-side surface and an aspherical eyeball-side surface and is formed in rotational symmetry with respect to a center of design of the progressive addition lens. The object-side surface includes a first stable region formed in rotational symmetry with respect to the center of design and including the center of design, and an aspherical region arranged outside of the first stable region to contact the first stable region and formed in rotational symmetry with respect to the center of design. A Peak to Valley value of a mean surface refractive power in the first stable region is 0.12 D or less.

Claims

1. A progressive addition lens formed for presbyopia with a positive distance power, the progressive addition lens comprising:

a near portion being arranged at a lower part of the progressive addition lens and having a power for viewing a near field;

a distance portion being arranged between an upper part and a center part of the progressive addition lens and having a power for viewing a distance field further than the near field; and

an intermediate portion connecting the distance portion and the near portion, wherein the progressive addition lens includes an aspherical object-side surface and an aspherical eyeball-side surface,

the object-side surface is formed in rotational symmetry with respect to a center point of the progressive addition lens,

the object-side surface includes a first stable region formed in rotational symmetry with respect to the center point and including the center point, and an aspherical region arranged outside of the first stable region so as to contact the first stable region and formed in rotational symmetry with respect to the center point such that the first stable region and the aspherical region are formed concentrically about the center point, the aspherical region including a curvature changing region in contact with an outside of the first stable region, a curvature of the curvature changing region in a meridional direction from the center point toward an outer periphery of the object-side surface being smaller than a curvature in the meridional direction in the first stable region, the aspherical region further including a second stable region arranged outside of the curvature changing region so as to contact the curvature changing region and formed in rotational symmetry with respect to the center point, a curvature in the meridional direction in the second stable region being smaller than a curvature in a sagittal direction perpendicular to the meridional direction in the second stable region,

the first stable region has a first PV value (Peak to Valley meaning a maximum change) of a mean surface refractive power in the first stable region,

the second stable region has a second PV value (Peak to Valley meaning a maximum change) of a mean surface refractive power in the second stable region that is greater than the first PV value,

the first PV value is less than a first PV threshold value,

the curvature in the first stable region is constant to the extent that the PV value is less than or equal to the first PV threshold value,

the second PV value is less than a second PV threshold value, the second PV threshold value being greater than the first PV threshold value, and

the curvature in the second stable region in the meridional direction is constant to the extent that the PV value is less than or equal to the second PV threshold value,

the first PV threshold value is 0.12 D, and

the second PV threshold value is 0.25 D.

2. The progressive addition lens according to claim 1, wherein one of the curvature in the meridional direction in the curvature changing region and a curvature in a sagittal direction perpendicular to the meridional direction in the curvature changing region is asymptotically reduced at points along a line in the meridional direction as a distance from the center point increases.

3. The progressive addition lens according to claim 1, wherein the curvature in the meridional direction in the curvature changing region is smaller than a curvature in a sagittal direction perpendicular to the meridional direction in the curvature changing region.

4. The progressive addition lens according to claim 1, wherein the eyeball-side surface includes a region opposite the curvature changing region that negates a change in refractive power of the curvature changing region.

5. The progressive addition lens according to claim 1, wherein a distance power measuring point is arranged in the first stable region.

6. The progressive addition lens according to claim 5, wherein a near power measuring point is arranged in the curvature changing region or the second stable region.

7. The progressive addition lens according to claim 1, wherein a near power measuring point is arranged in the first stable region.

8. The progressive addition lens according to claim 7, wherein a distance power measuring point is arranged in the curvature changing region or the second stable region.