METHOD FOR DESIGNING SPECTACLE LENS, SPECTACLE LENS, AND SPECTACLES

• US 20080024719A1
• Filed: 07/25/2007
• Published: 01/31/2008
• Est. Priority Date: 07/25/2006
• Status: Active Grant

• Current Assignee: Hoya Lens Manufacturing Philippines, Inc. (Hoya Corporation)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: KAMISHITA, Kaoru, ITO, Ayumu, KAGA, Tadashi
• Granted Patent: US 7,527,376 B2
• Time in Patent Office: Days
• US Class Current: 351/176
• CPC Class Codes: G02C 7/02 Lenses; Lens systems ; Methods of designing lenses
• CPC Class Codes: G02C 7/027 considering wearer's parameters

Abstract

A method of correcting the effects of a bend angle of 200 degrees or larger of spectacle frames, and astigmatism correcting characteristics in such spectacle frames. An exemplary embodiment of the present invention includes a design method for a spectacle lens mounted in a spectacle frame having a bend angle of 200 degrees or larger including an astigmatic power adding step, on the object side refractive surface or eyeball side refractive surface of the spectacle lens, for canceling astigmatic aberration caused by the bend angle of the spectacle frame, at a design reference point of the spectacle lens, and a step setting prismatic power by tilting the refractive surface, which is on an object side or an eyeball side, of the spectacle lens for canceling prismatic power caused by the bend angle of the spectacle frame, at the design reference point of the spectacle lens.

Claims

1. A method for designing a spectacle lens mounted in a spectacle frame having a bend angle of 200 degrees or larger, comprising:

adding astigmatic power on an object side refractive surface or an eyeball side refractive surface of the spectacle lens, for canceling aberration, caused by the bend angle of the spectacle frame, at a design reference point of the spectacle lens;

setting prismatic power by tilting the refractive surface, which is on an object side or an eyeball side, of the spectacle lens for canceling prismatic power, caused by the bend angle of the spectacle frame, at the design reference point of the spectacle lens;

extending a first reference meridian from the design reference point to the edge of the spectacle lens in a first direction which direction is a projected direction when a surface normal line at the design reference point of the spectacle lens having the bend angle of the spectacle frame is projected on a flat plane crossing a visual axis at a right angle;

extending a second reference meridian from the design reference point to the edge of the spectacle lens in a second direction opposite to the first direction;

extending a third reference meridian from the design reference point to the edge of the spectacle lens in a third direction, wherein the third reference meridian crosses the first reference meridian at the reference point at a right angle;

extending a fourth reference meridian from the design reference point to the edge of the spectacle lens in a fourth direction opposite to the third direction;

setting a plurality of reference meridians including at least the first reference meridian, the second reference meridian, the third reference meridian, and the fourth reference meridian;

obtaining aspherical surface quantities optimizing optical performance on the respective reference meridians after the setting step; and

obtaining aspherical surface quantities between the respective reference meridians by interpolation after the obtaining step.

2. The method for designing the spectacle lens according to claim 1, further comprising:

when the spectacle lens is an astigmatic power lens, extending a first astigmatic reference meridian from the design reference point of the spectacle lens to the edge of the spectacle lens in a fifth direction along a cylinder axis;

extending a second astigmatic reference meridian from the design reference point to the edge of the spectacle lens in a sixth direction opposite to the fifth direction;

extending a third astigmatic reference meridian from the reference design point to the edge of the spectacle lens in a seventh direction, wherein the third astigmatic reference meridian crosses the first astigmatic reference meridian at the design reference point at a right angle;

a fourth astigmatic reference meridian extending from the design reference point to the edge of the spectacle lens in an eighth direction opposite to the seventh direction; and

setting a plurality of reference meridians including at least the first reference meridian, the second reference meridian, the third reference meridian, the fourth reference meridian, the first astigmatic reference meridian, the second astigmatic reference meridian, the third astigmatic reference meridian, and the fourth astigmatic reference meridian.

3. The method for designing the spectacle lens according to claim 1, further comprising:

adding astigmatic power on the object side refractive surface or eyeball side refractive surface of the spectacle lens, which cancels aberration caused by a pantoscopic angle of the spectacle frame, at the design reference point of the spectacle lens; and

setting prismatic power by tilting the refractive surface, which is on an object side or an eyeball side, of the spectacle lens for canceling prismatic power, caused by the pantoscopic angle of the spectacle frame, at the design reference point of the spectacle lens;

wherein a line extending from the design reference point to the edge of the spectacle lens in a direction is the first reference meridian, the direction is a projected direction when a surface normal line at the design reference point of the spectacle lens having the bend angle and the pantoscopic angle of the spectacle frame is projected on a flat plane crossing the visual axis at right angles.

4. The method for designing the spectacle lens according to claim 1, wherein the first reference meridian, the second reference meridian, the third reference meridian, and the fourth reference meridian occur where an effect of the bend angle is at a maximum and a minimum.

5. A spectacle lens manufactured by the method for designing the spectacle lens according to claim 1.

6. A spectacle lens that is mounted in a spectacle frame having a bend angle of 200 degrees or larger and is an astigmatic power line according to the method recited in claim 1.

7. A pair of spectacle eyeglasses having spectacle lenses, wherein the spectacle lenses are astigmatic power lenses, and a spectacle frame has a bend angle of 200 degrees or larger.