Progressive multi-focus lens capable of effectively reducing peripheral astigmatism

Abstract

The utility model relates to a progressive multifocal lens capable of effectively reducing peripheral astigmatism. Reasonable weight values are set for each area of the front surface of the lens according to the focal power required when a wearer sees an object at a long distance and a short distance and the focal power of the rear surface of the lens, and the surface rise of the front surface of the lens meets a minimization function. According to the lens provided by the utility model, the peripheral astigmatism can be more effectively reduced under the condition that the surface focal power is close to the preset focal power, and the peripheral maximum astigmatism is controlled within 75% of light adding degree, so that the wearing comfort is improved.

Description

Technical Field

[0001] The utility model relates to a progressive multi-focal lens which can effectively reduce peripheral astigmatism and belongs to the technical field of optical design. Background Art

[0002] Traditional single-focal glasses cannot take into account far, near and medium-distance vision at the same time due to their fixed optical focal length; although bifocal glasses solve the patient's needs for far and near vision, they are not clear for medium-distance vision, and there is a dividing line in the middle of the lens, which affects the appearance and field of vision; although trifocal glasses can take into account near, medium and long-distance vision, the transition between each zone is abrupt, and there is still the problem of uncomfortable wearing.

[0003] Progressive multifocal spectacle lenses are spectacle lenses whose surface focal power continuously changes due to the continuous change of surface curvature. Chinese invention patent CN113253482A provides a multifocal spectacle lens with a two-stage meridian design. Although it can flexibly obtain meridian focal power change curves of different shapes to obtain progressive multifocal lenses that meet user requirements, the peripheral astigmatism of the designed lens is greater than one plus diopter, which affects the visual imaging effect. The document "Multi-axis progressive zoom glasses design" (Optical Technology, 2015, 41(04): 355-359) proposes a multi-axis progressive multifocal lens design method, which selects the actual pupil used by the human eye as the small pupil within the aperture of the glasses to design a meta-lens corresponding to the small pupil; on the meridian plane, the focal power between the far vision point and the near vision point of the lens needs to be determined by an 8th-order polynomial; in the pupil plane, the focal power of the pupils including the far vision area and the near vision area adjacent to the far vision area are respectively distributed in a hyperbolic type and a parabolic type. Although this design method can make the surface optical power of the lens close to the preset optical power, the peripheral astigmatism of the lens is large. When the addition power is 0.75D, the maximum peripheral astigmatism of the lens is close to 3.50D, which exceeds the limit that the human eye can withstand. Summary of the invention

[0004] The utility model aims at the deficiencies of the prior art and provides a progressive multifocal lens which can more effectively reduce peripheral astigmatism while ensuring that the optical power of the lens is close to the preset optical power and control the astigmatism within 75% of the addition power.

[0005] The technical solution to achieve the purpose of the utility model is to provide a progressive multifocal lens that effectively reduces peripheral astigmatism, the lens comprising an effective visual area consisting of a far vision area, a near vision area and a progressive channel, and a peripheral astigmatism area; the rear surface of the lens is a spherical surface, the front surface is a progressive surface, and the surface shape of the front surface of the lens has a sagittal height z(x,y) that satisfies the minimization function J(z(x,y)):

[0006]

[0007] where, Ω is the integral domain of the surface;

[0008] α(x, y) is the weight distribution function related to astigmatism, and β(x, y) is the weight distribution function related to the optical power; within the effective visual area of the lens, the high weight values assigned to the weight distribution functions are: 15 < α(x, y) < 25, 15 < β(x, y) < 25; within the peripheral astigmatism area of the lens, the low weight values assigned to the weight distribution functions are:

[0009] 0 < α(x, y) < 1, 0 < β(x, y) < 1;

[0010] P d (x, y) is the preset optical power of the distant vision area; P n (x, y) is the preset optical power of the near vision area;

[0011] k is the curvature adjustment factor, and its value range is 1 < k < 2; m is the translation factor, and its value range is -3 < m < 0;

[0012] n is the refractive index of the lens;

[0013] A(x, y) is the distance from any point on the front surface of the lens to the center point of the front surface of the lens;

[0014] k1(x, y) and k2(x, y) are respectively the maximum and minimum principal curvatures corresponding to each point on the front surface of the lens, and k1(x, y), k2(x, y) satisfy the conditions:

[0015] H(x, y) = (k1(x, y) + k2(x, y)) / 2,

[0016] K(x, y) = k1(x, y) * k2(x, y)),

[0017] H(x, y) and K(x, y) are respectively the mean curvature and Gaussian curvature of the front surface of the lens, and the expressions are:

[0018]

[0019] where, z(x, y) x and z(x, y) y are the first-order partial derivatives of the surface sag z(x, y) of any point on the front surface of the lens in the x-direction and y-direction respectively; z(x, y) xx and z(x, y) yy are the second-order partial derivatives of the surface sag z(x, y) of any point on the front surface of the lens in the x-direction and y-direction respectively; z(x, y) xy is the second-order partial derivative of the surface sag z(x, y) of any point on the front surface of the lens first in the x-direction and then in the y-direction.

[0020] The utility model provides a progressive multi-focal lens which can effectively reduce peripheral astigmatism, wherein the astigmatism in the peripheral astigmatism zone is less than or equal to 75% of the addition power.

[0021] In the present invention, the coordinate system is a Cartesian space rectangular coordinate system constructed with the center point of the front surface of the lens as the origin O, the positive direction of the x-axis is horizontally to the right along the sagittal direction of the front surface of the lens, the positive direction of the y-axis is vertically upward along the meridian direction of the front surface of the lens, the z-axis is perpendicular to the xoy plane, and satisfies the right-hand rule with the x-axis and the y-axis.

[0022] Compared with the prior art, the beneficial effects of the utility model are:

[0023] The peripheral astigmatism of the progressive addition lens provided by the prior art is generally greater than one addition, which affects the visual imaging effect. The surface sagittal height of the progressive addition lens provided by the utility model satisfies the minimization function condition, and can more effectively reduce the peripheral astigmatism and control the maximum peripheral astigmatism within 75% addition while ensuring that the lens focal power is close to the preset focal power. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the regional distribution of progressive multifocal lenses;

[0025] Figure 2 This is a sagittal diagram of the front surface of a progressive addition lens that effectively reduces peripheral astigmatism, provided in Example 1 of the utility model;

[0026] Figure 3 This is a spherical power distribution diagram of a progressive addition lens that effectively reduces peripheral astigmatism provided by Example 1 of the utility model;

[0027] Figure 4 This is a cylinder power distribution diagram of a progressive addition lens that effectively reduces peripheral astigmatism provided by Example 1 of the utility model;

[0028] Figure 5 This is a sagittal diagram of the front surface of a progressive addition lens that effectively reduces peripheral astigmatism, provided in Example 2 of the utility model;

[0029] Figure 6 This is a spherical power distribution diagram of a progressive addition lens that effectively reduces peripheral astigmatism, provided in Example 2 of the utility model;

[0030] Figure 7 This is a cylinder power distribution diagram of a progressive addition lens that effectively reduces peripheral astigmatism, provided in Example 2 of the utility model.

[0031] Figure 1 Middle: 1. Far vision zone; 2. Near vision zone; 3. Progressive channel; 4. Peripheral astigmatism zone. DETAILED DESCRIPTION

[0032] The technical solution of the utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0033] Example 1

[0034] This embodiment provides a progressive addition lens that effectively reduces peripheral astigmatism.

[0035] See attached Figure 1 , which is a schematic diagram of the regional distribution of progressive multifocal lenses. Progressive multifocal lenses include far vision zone 1, near vision zone 2, progressive channel 3 and peripheral astigmatism zone 4; the far vision zone, near vision zone and progressive channel together constitute the effective visual zone. The far vision zone is located in the upper area of ​​the lens and is used for the human eye to see distant objects; the near vision zone is located in the lower area of ​​the lens and is used for the human eye to see nearby objects; the progressive channel is located between the far vision zone and the near vision zone and is used for the human eye to see medium-distance objects; the peripheral astigmatism zone is mainly located on both sides of the progressive channel and the near vision zone, which will affect the human eye's clear vision.

[0036] In this embodiment, the rear surface of the lens is a spherical surface, and the front surface is a progressive surface. According to the needs of the eye examination results of the wearer, the lens parameters are set as follows:

[0037] Myopia 2D Presbyopia degree (addition of light) 2D Lens refractive index 1.53 <![CDATA[Predetermined optical power P of the far vision zone in the front surface d (x,y)]]> 2D <![CDATA[Predetermined optical power P of the near vision zone in the front surface n (x,y)]]> 4D The optical power of the back surface of the lens 4D Curvature adjustment factor k 1.8 Translation factor m -2

[0038] In this embodiment, the coordinate system is a Cartesian space rectangular coordinate system constructed with the center point of the front surface of the lens as the origin O, the positive direction of the x-axis is horizontally to the right along the sagittal direction of the front surface of the lens, the positive direction of the y-axis is vertically upward along the meridian direction of the front surface of the lens, the z-axis is perpendicular to the xoy plane, and satisfies the right-hand rule with the x-axis and the y-axis.

[0039] In this embodiment, the lens radius is 30 mm, the front surface of the lens is divided into a 61×61 matrix, the distance between each point is 1.0 mm, and the vector height z(x, y) of the front surface of the lens satisfies the minimization function J(z(x, y)):

[0040]

[0041] Wherein, z(x,y) is the sag of the lens surface; Ω is the integral domain of the surface; α(x,y) is the weight distribution function related to astigmatism, β(x,y) is the weight distribution function related to optical power; k1(x,y) and k2(x,y) are the maximum and minimum principal curvatures corresponding to each point on the front surface of the lens, respectively; P d (x, y) is the preset optical power of the far vision area; P n(x, y) is the preset optical focal length of the near vision zone; k is the curvature adjustment factor; A(x, y) is the distance from any point on the front surface to the center point of the front surface of the lens; m is the translation factor, and n is the refractive index of the lens.

[0042] k1(x, y) and k2(x, y) are the maximum and minimum principal curvatures corresponding to each point on the front surface of the lens. In the prior art, k1(x, y) and k2(x, y) are expressed as:

[0043] H(x,y)=(k1(x,y)+k2(x,y)) / 2,

[0044] K(x,y)=k1(x,y)*k2(x,y)),

[0045] H(x,y) and K(x,y) are the average curvature and Gaussian curvature of the front surface of the lens, respectively, and the expressions are:

[0046]

[0047] Among them, z(x,y) x and z(x,y) y is the first-order partial derivative of the surface vector height z(x,y) of any point on the front surface of the lens in the x direction and the y direction respectively; z(x,y) xx and z(x,y) yy is the second-order partial derivative of the surface vector height z(x,y) of any point on the front surface of the lens in the x-direction and y-direction respectively; z(x,y) xy It is the second-order partial derivative of the surface vector z(x,y) of any point on the front surface of the lens, first in the x direction and then in the y direction.

[0048] In this embodiment, in the effective visual area of ​​the lens, high weight values ​​are assigned to the weight distribution function related to astigmatism and the weight distribution function related to optical power: a(x, y) = 20, β(x, y) = 20; in the peripheral astigmatism area of ​​the lens, low weight values ​​are assigned to the weight distribution function related to astigmatism and the weight distribution function related to optical power: a(x, y) = 0.5,

[0049] β(x,y)=0.5.

[0050] The front surface sagitta z(x, y) of the progressive addition lens provided in this embodiment satisfies the minimization function. The front surface sagitta distribution diagram calculated by the above formula is shown in the attached Figure 2 ,Depend on Figure 2 It can be seen that the surface of the lens is smooth and has no abrupt changes. Figure 3, is a spherical power distribution diagram of the progressive multifocal lens provided in this embodiment. From the far vision zone to the near vision zone, the optical power distribution on the lens surface presents a gradual trend, there is no jump, and the degree requirement of the patient for clear vision is met.

[0051] See attached Figure 4 , which is a cylinder distribution diagram of the progressive multifocal lens provided in this embodiment. The peripheral astigmatism area is concentrated on both sides of the progressive channel and the near vision area, the astigmatism in the effective visual area is small, and the maximum astigmatism on the entire lens is controlled within 75% addition.

[0052] Example 2

[0053] This embodiment provides a progressive addition lens that effectively reduces peripheral astigmatism.

[0054] In this embodiment, the rear surface of the lens is a spherical surface, and the front surface is a progressive surface. According to the needs of the eye examination results of the wearer, the lens parameters are set as follows:

[0055] Myopia 3D Presbyopia degree (addition of light) 1D Lens refractive index 1.49 <![CDATA[The preset optical power P of the intermediate distance viewing zone in the front surface d (x,y)]]> 4D <![CDATA[Preset optical power P of the near vision area in the front surface n (x,y)]]> 5D The optical power of the back surface of the lens 7D Curvature adjustment factor k 1.2 Translation factor m -1.5

[0056] In this embodiment, in the effective visual area of ​​the lens, high weight values ​​are assigned to the weight distribution function related to astigmatism and the weight distribution function related to optical power: a(x, y) = 23, β(x, y) = 23; in the peripheral astigmatism area of ​​the lens, low weight values ​​are assigned to the weight distribution function related to astigmatism and the weight distribution function related to optical power: a(x, y) = 0.7,

[0057] β(x,y)=0.7.

[0058] The front surface sagitta z(x, y) of the progressive addition lens provided in this embodiment satisfies the minimization function. The front surface sagitta distribution diagram calculated by the relevant formula in Example 1 is shown in the attached drawing. Figure 5 ,Depend on Figure 5 It can be seen that the surface of the lens is smooth and has no mutations.

[0059] See attached Figure 6 , is the spherical power distribution diagram of the progressive multifocal lens provided in this embodiment. The optical power on the lens surface is basically consistent with the preset optical power, which meets the patient's degree requirements for clear vision; and from the far vision area to the near vision area, the optical power distribution on the lens surface presents a gradual trend, without abrupt changes.

[0060] See attached Figure 7 , which is a cylindrical power distribution diagram of the progressive multifocal lens provided in this embodiment. The peripheral astigmatism area is concentrated on both sides of the progressive channel and the near vision area, the effective visual area is large, and the maximum astigmatism on the entire lens is controlled within 75% addition.

[0061] Results show that the progressive addition lens for effectively reducing peripheral astigmatism provided by the utility model can more effectively reduce peripheral astigmatism and control the maximum peripheral astigmatism within 75% addition power while ensuring that the optical power of the lens is close to the preset optical power.

Claims

1. A progressive multifocal lens that effectively reduces peripheral astigmatism, the lens comprising an effective visual area consisting of a far vision area (1), a near vision area (2) and a progressive channel (3), and a peripheral astigmatism area (4); the rear surface of the lens is a spherical surface, and the front surface is a progressive surface, characterized in that: The front surface of the lens has a sagittal height Satisfy the minimization function : ， in, is the integration domain of the surface; is the weight distribution function related to astigmatism, is a weight distribution function related to the optical power; within the effective visual area of ​​the lens, the high weight values ​​assigned to the weight distribution function are: , ; In the peripheral astigmatism area of ​​the lens, the low weight values ​​assigned to the weight distribution function are: , ; Preset optical power for distance vision; The preset optical power for near vision area; k is the curvature adjustment factor, and its value range is 1< k <2; m is the translation factor, the value range is -3< m <0; n is the refractive index of the lens; A ( x , y ) is the distance from any point on the front surface of the lens to the center point of the front surface of the lens; , are the maximum and minimum principal curvatures corresponding to each point on the front surface of the lens, , Requirements: ， ， , are the average curvature and Gaussian curvature of the front surface of the lens, respectively, and the expression is: ， ； in, and is the surface height of any point on the front surface of the lens Respectively x Direction and y First-order partial derivative in direction; and is the surface height of any point on the front surface of the lens Respectively x Direction and y Second-order partial derivatives in direction; is the surface height of any point on the front surface of the lens First x Direction after y Second-order partial derivative in direction.

2. A progressive addition lens for effectively reducing peripheral astigmatism according to claim 1, characterized in that: The astigmatism in the peripheral astigmatism zone of the lens is ≤75% addition power.

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