PROGRESSIVE ADDITION LENS

• US 20170082870A1
• Filed: 06/03/2015
• Published: 03/23/2017
• 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
• Granted Patent: US 10,288,903 B2
• Time in Patent Office: Days
• 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

A progressive addition lens includes a portion having a power for viewing a near field, a portion having a power for viewing a distance field further than the near field, and an 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 PV value (Peak to Valley) of a mean surface refractive power in the first stable region is 0.12 D or less.

Claims

1. A progressive addition lens comprising:

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,

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 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 so as to contact the first stable region and formed in rotational symmetry with respect to the center of design, and

a PV value (Peak to Valley) of a mean surface refractive power in the first stable region is 0.12 D or less.

2. The progressive addition lens according to claim 1, wherein the rotation symmetrical aspherical region includes a curvature changing region in contact with an outside of the first stable region and satisfying the following Condition 1:

Condition 1

A curvature in a meridional direction from the center of design toward an outer periphery of the object-side surface is larger than a curvature in the meridional direction in the first stable region.

3. The progressive addition lens according to claim 2, 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 increased toward the meridional direction.

4. The progressive addition lens according to claim 2, wherein

the curvature in the meridional direction in the curvature changing region is larger than a curvature in a sagittal direction perpendicular to the meridional direction in the curvature changing region.

5. The progressive addition lens according to claim 2, wherein

the rotation symmetrical aspherical region includes 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 of design, and

a curvature in the meridional direction in the second stable region is larger than a curvature in a sagittal direction perpendicular to the meridional direction in the second stable region.

6. The progressive addition lens according to claim 2, wherein

the rotation symmetrical aspherical region includes 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 of design, and

a curvature in the meridional direction in the second stable region is substantially constant.

7. The progressive addition lens according to claim 5, wherein

the PV value (Peak to Valley) of the mean surface refractive power in the meridional direction in the second stable region is 0.25 D or less.

8. The progressive addition lens according to claim 5, wherein

a distance power measuring point is arranged in the first stable region.

9. The progressive addition lens according to claim 8, wherein

a near power measuring point is arranged in the curvature changing region or the second stable region.

10. The progressive addition lens according to claim 5, wherein

a near power measuring point is arranged in the first stable region.

11. The progressive addition lens according to claim 10, wherein

a distance power measuring point is arranged in the curvature changing region or the second stable region.

12. The progressive addition lens according to claim 2, wherein

the eyeball-side surface includes a surface refractive power change which cancels a change of a surface refractive power due to the curvature changing region of the object-side surface.