Multi-visual-axis progressive ring focus lens and design method

Abstract

The invention discloses a multi-visual-axis progressive ring focus lens and a design method. And constructing a minimization model satisfied by the rise of the surface of the lens at a multi-visual-axis angle, and solving the minimization model to obtain the rise value of the surface of the multi-visual-axis progressive ring focus lens so as to complete the construction of the surface type of the surface of the lens. The invention provides a multi-visual-axis progressive ring focus lens, and aims to solve the problem that a traditional progressive multi-focus lens only has a single visual axis from a far visual area to a near visual area in the meridian direction and cannot meet the requirement that the visual axis can rotate in the dynamic object viewing process of far and near switching of human eyes. The required focal power during dynamic object viewing is provided for human eyes along the 360-degree multi-visual-axis direction; and the focal power is in smooth transition from the central fixed focus area to the peripheral defocus area and is slowly increased, so that the astigmatism at the periphery of the lens is mainly gathered at the edge of the lens, and the degree of influence on clear vision of an object by human eyes is reduced.

Description

Technical Field

[0001] The invention relates to a multi-visual-axis progressive annular focal lens and a design method thereof, belonging to the technical field of optical design. Background Art

[0002] At present, adolescent patients with refractive errors mainly use the following two methods to correct their optical system: one is to wear optical lenses such as frame glasses or contact lenses; the other is to use excimer laser correction surgery and other means to change a certain refractive element of the human eye. Single-vision lenses require appropriate adjustment of the eyes for close-range use. Long-term wearing will cause eye fatigue, aggravate myopia and deform the eyeball. Bifocals cannot overcome the phenomenon of leaping of optical power, and image jump will occur. The optical power of progressive multifocal lenses decreases continuously from the far vision zone to the near vision zone through the progressive transition zone, which will maximize the improvement of eye fatigue and effectively relieve eye fatigue at close range. However, there are certain blind spots on both sides of the progressive transition zone of progressive multifocal lenses, which will affect the clear vision of the human eye at medium and long distances; and progressive multifocal lenses only have a single visual axis from the far vision zone to the near vision zone along the meridian direction, which cannot adapt to the situation where the visual axis rotates during the dynamic vision process of switching between far and near.

[0003] Before the present invention was made, the document "Progressive Angle Focus Freeform Surface Lens Design" (Optical Technology, 2018, 44(04): 404-408.) proposed a design method for a progressive angle focus freeform surface lens, which constructs a multifocal lens from the perspective of peripheral defocus control and gradual change of optical power. A circular central fixed focus area is formed in the center of the lens, and multiple annular peripheral fixed focus areas are formed on the periphery. The optical power of the lens gradually changes from the inside to the outside along the lens meridian and the horizontal axis of the lens according to the set optical power high-order polynomial; based on the principle of coincidence of the tangent planes of the edge points of adjacent fixed focus areas, the vector height of all points on the back surface of each fixed focus area is calculated in sequence from the inside to the outside, and then the back surface of the lens is generated based on the vector height data of all points on the back surface of all fixed focus areas. Although the design method can make the optical power and astigmatism of the lens meet the theoretical design requirements, only the visual axis along the horizontal and meridian directions of the lens cannot fully meet the needs of the human eye for dynamic vision. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a multi-axis progressive annular focus lens and a design method thereof, which can push peripheral astigmatism to the outer edge of the lens at a 360° multi-axis angle.

[0005] The technical solution to achieve the purpose of the present invention is to provide a design method for a multi-axis progressive ring focus lens, wherein the lens includes a central fixed focus area and a peripheral defocus area, and includes the following steps:

[0006] (1) Construct a minimization model M(z(x,y)) that satisfies the lens surface sagittal height z(x,y): Wherein, z(x,y) is the vector height value of each point on the lens surface; Ω is the integral domain of the surface; A(x,y) is the weight distribution function related to astigmatism, and B(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 lens surface, respectively; C(x,y) is the preset average curvature of the lens surface;

[0007] (2) Determine the preset average curvature C(x,y) of the lens surface: C(x,y)=P(x,y) / (n-1) Where P(x,y) is the surface power of the lens; n is the refractive index of the lens;

[0008] (3) Determine the optical power distribution P(x,y) on the lens surface: P(x,y)=P c (x,y)+(P o (x,y)-P c (x,y))*sin(π(pa) / 2(ba)) Among them, P c (x, y) is the preset optical power of the central fixed focus area; P o (x, y) is the maximum preset optical power of the peripheral defocus area; p is the distance from the center point of the lens to any point in the radial direction; a is the width adjustment factor of the central fixed focus area; b is the progressive optical power adjustment factor;

[0009] (4) Through the average curvature H(x, y) and Gaussian curvature K(x, y) of the lens surface, the relationship between the maximum principal curvature k1(x, y), the minimum principal curvature k2(x, y) and the surface sag z(x, y) is constructed: H(x,y)=(k1(x,y)+k2(x,y)) / 2, K(x,y)=k1(x,y)*k2(x,y)), Among them, z(x,y) x 、z(x,y) y is the first-order partial derivative of the surface vector height z(x,y) of any point on the lens surface in the x direction and y direction respectively; z(x,y) xx 、z(x,y) yy is the second-order partial derivative of the surface vector z(x,y) of any point on the lens surface in the x and y directions respectively; z(x,y)xy The second partial derivative of the surface sag z(x,y) at any point on the lens surface, first in the x direction and then in the y direction;

[0010] (5) Calculate the sag value z(x,y) of the multi-axis progressive annular focus lens surface from the minimized model M(z(x,y)) constructed in step (1).

[0011] A design method for a multi-axis progressive annular focus lens provided by the present invention assigns a low weight value: 0 < A(x,y) < 1 to the weight distribution function related to astigmatism in the central fixed-focus area of the lens with a radial distance of 0 < p ≤ 18; in the peripheral defocus area of the lens with a radial distance of 18 < p ≤ 30, a high weight value: 0 < A(x,y) < 40 is assigned to the weight distribution function related to astigmatism.

[0012] In the central fixed-focus area of the lens with a radial distance of 0 < p < 18, a high weight value: 295 < B(x,y) < 305 is assigned to the weight distribution function related to the optical power; in the peripheral defocus area of the lens with a radial distance of 18 < p ≤ 26, a low weight value: 25 < B(x,y) < 35 is assigned to the weight distribution function related to the optical power; in the peripheral defocus area of the lens with a radial distance of 26 < p ≤ 30, a high weight value: 295 < B(x,y) < 305 is assigned to the weight distribution function related to the optical power.

[0013] A design method for a multi-axis progressive annular focus lens provided by the present invention has a value range of the width adjustment factor a of the central fixed-focus area: 15 < a < 20. The value range of the progressive optical power adjustment factor b is: 20 < b < 25.

[0014] The design solution of the present invention also includes a multi-axis progressive annular focus lens obtained by the above design method.

[0015] In the technical solution of the present invention, the coordinate system is a Cartesian space rectangular coordinate system constructed with the center point of the lens surface as the origin O. The positive direction of the x-axis is horizontally to the right along the sagittal direction of the lens surface, the positive direction of the y-axis is vertically upward along the meridian direction of the lens surface, the z-axis is perpendicular to the xoy plane, and satisfies the right-hand rule with the x-axis and the y-axis.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] The present invention proposes a design method for a multi-axis progressive ring-focus lens from the perspective of multiple visual axes, which provides the required optical power for dynamic vision for the human eye along the 360° multi-axis direction, solving the problem that the traditional progressive multifocal lens has only a single visual axis from the far vision zone to the near vision zone along the meridian direction, and cannot meet the requirement that the visual axis will rotate during the dynamic vision process of switching between far and near. And by making the optical power smoothly transition from the central fixed focus area to the peripheral defocus area and slowly increase, the peripheral astigmatism of the lens is mainly concentrated at the edge of the lens, reducing the degree of influence on the clear vision of the human eye. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the regional distribution of a multi-axis progressive ring focus lens provided by an embodiment of the present invention.

[0019] Figure 2 The present invention provides a surface curvature distribution diagram of a multi-axis progressive addition cyclofocal lens.

[0020] Figure 3 It is a weight distribution diagram of a function A(x, y) related to astigmatism of a multi-axis progressive addition toric lens provided by an embodiment of the present invention.

[0021] Figure 4 It is a weight distribution diagram of a function B(x, y) related to the optical power of a multi-axis progressive addition ring focus lens provided by an embodiment of the present invention.

[0022] Figure 5 It is a sagittal height diagram of a multi-axis progressive cyclofocal lens provided by an embodiment of the present invention.

[0023] Figure 6 The present invention provides a spherical power distribution diagram of a multi-axis progressive ring focus lens.

[0024] Figure 7 The cylindrical power distribution diagram of a multi-axis progressive ring focus lens provided by an embodiment of the present invention.

[0025] Figure 1 Middle: 1. Central fixed focus area; 2. Peripheral out-of-focus area. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0027] Example 1

[0028] This embodiment provides a multi-axis progressive ring focus lens and a design method.

[0029] See attached Figure 1, which is a regional distribution diagram of a multi-axis progressive ring focus lens provided in this embodiment, and the multi-axis progressive ring focus lens includes a central fixed focus area 1 and a peripheral defocus area 2. The central fixed focus area is used to correct the myopic defocus of the macular area to achieve the effect of clear vision; the peripheral defocus area introduces continuously changing optical power at different radial distances of the lens, forms myopic defocus in the peripheral area of ​​the retina, and has the effect of preventing and controlling myopia.

[0030] In this embodiment, according to the wearer's eye examination results and glasses fitting needs, the lens parameters are set as follows: Preset focal length of the central focus area -4.0D Maximum preset focal length in the peripheral out-of-focus area -3.0D Lens refractive index 1.53 Width adjustment factor a of the central focus area 18mm Progressive diopter adjustment factor b 24mm

[0031] In this embodiment, the radius of the lens is 30 mm, the lens surface is divided into a 61×61 matrix, and the distance between each point is 1.0 mm.

[0032] In this embodiment, the coordinate system is a Cartesian space rectangular coordinate system constructed with the center point of the lens surface as the origin O, the positive direction of the x-axis is horizontally to the right along the sagittal direction of the lens surface, the positive direction of the y-axis is vertically upward along the meridian direction of the lens surface, the z-axis is perpendicular to the xoy plane, and satisfies the right-hand rule with the x-axis and the y-axis.

[0033] The specific implementation steps of lens design are as follows:

[0034] (1) Construct a minimization model M(z(x,y)) satisfied by the lens surface sagittal height z(x,y), that is, the minimization model M(z(x,y)) between the principal curvature difference and the average curvature of the lens surface and the preset principal curvature difference and the average curvature is shown in formula (1): Among them, z(x,y) is the vector height value of each point on the lens surface; Ω is the integral domain of the surface; A(x,y) is the weight distribution function related to astigmatism, B(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 lens surface respectively; C(x,y) is the preset average curvature of the lens surface.

[0035] (2) Determine the preset average curvature C(x, y) of the lens surface as shown in formula (2): C(x,y)=P(x,y) / (n-1)(2) Among them, P(x,y) is the optical power of the lens surface; n is the refractive index of the lens.

[0036] (3) Determine the focal power distribution P(x, y) on the lens surface as shown in formula (3): P(x,y)=P c (x,y)+(P o (x,y)-P c(x,y))*sin(π(p - a) / 2(b - a))(3) Among them, P c (x,y) is the preset optical power of the central focusing area; P o (x,y) is the maximum preset optical power of the peripheral defocus area; p is the distance from the center point of the lens to any point on the radial direction; a is the width adjustment factor of the central focusing area; b is the progressive optical power adjustment factor.

[0037] See Appendix Figure 2 , which is the surface curvature distribution diagram of a multi - axis progressive annular - focus lens provided by this embodiment.

[0038] (4) Reasonably allocate the weight distribution function on the lens surface:

[0039] In the central focusing area of the lens, that is, within the radial distance 0 < p ≤ 18, assign a low weight value to the weight distribution function related to astigmatism: A(x,y) = 0.5; in the peripheral defocus area of the lens, that is, within the radial distance 18 < p ≤ 30, assign a high weight value to the weight distribution function related to astigmatism: A(x,y) = 30. See Appendix Figure 3 , which is the weight distribution diagram of the function A(x,y) related to astigmatism of a multi - axis progressive annular - focus lens provided by this embodiment.

[0040] In the central focusing area of the lens, that is, within the radial distance 0 < p ≤ 18, assign a high weight value to the weight distribution function related to optical power: B(x,y) = 300; in the peripheral defocus area of the lens, within the radial distance 18 < p ≤ 26, assign a low weight value to the weight distribution function related to optical power: B(x,y) = 30; in the peripheral defocus area of the lens, within the radial distance 26 < p ≤ 30, assign a high weight value to the weight distribution function related to optical power: B(x,y) = 300. See Appendix Figure 4 , which is the weight distribution diagram of the function B(x,y) related to optical power of a multi - axis progressive annular - focus lens provided by this embodiment.

[0041] (5) After reasonably allocating the weight function on the lens surface, establish a simultaneous relationship between the maximum and minimum principal curvatures, that is, k1(x,y) and k2(x,y), and the surface sag z(x,y) through the mean curvature H(x,y) and the Gaussian curvature K(x,y).

[0042] The relationships between the mean curvature H(x,y) and the Gaussian curvature K(x,y) and the maximum principal curvature k1(x,y) and the minimum principal curvature k2(x,y) are shown in equations (4) and (5) respectively: H(x,y) = (k1(x,y) + k2(x,y)) / 2(4) K(x,y) = k1(x,y)*k2(x,y))(5)

[0043] The relationship between the mean curvature H(x, y) and Gaussian curvature K(x, y) and the surface sagittal height z(x, y) is shown in equations (6) and (7) respectively: 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 lens surface in the x direction and y direction respectively; z(x,y) xx and z(x,y) yy is the second-order partial derivative of the surface vector z(x,y) of any point on the lens surface in the x and y directions respectively; z(x,y) xy It is the second-order partial derivative of the surface vector z(x,y) of any point on the lens surface, first in the x direction and then in the y direction.

[0044] (6) By solving the minimization model, the vector height value z(x,y) of the multi-axis progressive annular lens is obtained.

[0045] See attached Figure 5 , is a surface vector height distribution diagram of a multi-axis progressive ring focus lens provided in this embodiment. It can be seen that the surface distribution of the lens is smooth and has no sudden changes.

[0046] See attached Figure 6 , is a spherical power distribution diagram of a multi-axis progressive ring focus lens provided in this embodiment. There is a circular area with a focal power of -3.96D in the center of the lens. The national standard tolerance of eyeglass lenses is ±0.12D. From the central fixed focus area to the peripheral defocus area, the focal power distribution on the lens shows a progressive trend along the radial direction. There is no jump in the focal power of the entire lens, indicating that the focal power on the lens surface meets the design requirements and provides the human eye with the focal power required for clear vision along the 360° multi-axis direction.

[0047] See attached Figure 7 , is a cylindrical power distribution diagram of a multi-axis progressive ring focus lens provided in this embodiment; the astigmatism is mainly concentrated at the edge of the lens, and the astigmatism within the center range of the lens is small and approximately zero.

[0048] The results show that the multi-axis progressive ring focus lens and design method provided by the present invention provide the required optical power for dynamic vision for the human eye along the 360° multi-axis direction, solving the problem that the traditional progressive multi-focal lens has only a single visual axis from the far vision zone to the near vision zone along the meridian direction, which cannot meet the requirement that the visual axis will rotate during the dynamic vision process of switching between far and near. And by making the optical power smoothly transition from the central fixed focus area to the peripheral defocus area and slowly increase, the peripheral astigmatism of the lens is mainly concentrated at the edge of the lens, reducing the degree of influence on the clear vision of the human eye.

Claims

1. A method for designing a multi-axis progressive annular lens, the lens comprising a central fixed focus area (1) and a peripheral defocus area (2), characterized in that It includes the following steps: (1) Construct a minimization model M(z(x, y)) satisfied by the sagittal height z(x, y) of the lens surface: where z(x, y) is the sagittal height value of each point on the lens surface; Ω is the integral domain of the surface; A(x, y) is the weight distribution function related to astigmatism, and B(x, y) is the weight distribution function related to the optical power; k1(x, y) and k2(x, y) are the maximum and minimum principal curvatures corresponding to each point on the lens surface respectively; C(x, y) is the preset average curvature of the lens surface. (2) Determine the preset average curvature C(x, y) of the lens surface: C(x, y) = P(x, y) / (n - 1) where P(x, y) is the optical power of the lens surface; n is the refractive index of the lens. (3) Determine the optical power distribution P(x, y) of the lens surface: P(x,y)=P c (x, y)+(P o (x,y)-P c (x, y))*sin(π(pa) / 2(ba)) Among them, P c (x, y) is the preset optical power of the central fixed focus area; P o (x, y) is the maximum preset optical power of the peripheral defocus area; p is the distance from the center point of the lens to any point in the radial direction; a is the width adjustment factor of the central fixed focus area; b is the progressive optical power adjustment factor; (4) Construct the correlation between the maximum principal curvature k1(x, y), the minimum principal curvature k2(x, y) and the surface sagittal height z(x, y) through the average curvature H(x, y) and the Gaussian curvature K(x, y) of the lens surface: H(x, y) = (k1(x, y) + k2(x, y)) / 2, K(x, y) = k1(x, y) * k2(x, y), Among them, z(x, y) x 、z(x,y) y is the first-order partial derivative of the surface vector height z(x, y) of any point on the lens surface in the x direction and y direction respectively; z(x, y) xx 、z(x,y) yy is the second-order partial derivative of the surface vector z(x, y) of any point on the lens surface in the x and y directions respectively; z(x, y) xy It is the second-order partial derivative of the surface vector height z(x,y) of any point on the lens surface first in the x direction and then in the y direction; (5) Calculate the sagittal height value z(x, y) of the multi-axis progressive annular focus lens surface according to the minimization model M(z(x, y)) constructed in step (1).

2. The design method of a multi-axis progressive ring focus lens according to claim 1, characterized in that: In the central fixed-focus area of the lens with a radial distance of 0 < p ≤ 18, assign a low weight value to the weight distribution function related to astigmatism: 0 < A(x, y) < 1; in the peripheral defocus area of the lens with a radial distance of 18 < p ≤ 30, assign a high weight value to the weight distribution function related to astigmatism: 0 < A(x, y) < 40.

3. The design method of a multi-axis progressive ring focus lens according to claim 1, characterized in that: In the central fixed-focus area of the lens with a radial distance of 0 < p < 18, assign a high weight value to the weight distribution function related to the optical power: 295 < B(x, y) < 305; in the peripheral defocus area of the lens with a radial distance of 18 < p ≤ 26, assign a low weight value to the weight distribution function related to the optical power: 25 < B(x, y) < 35; in the peripheral defocus area of the lens with a radial distance of 26 < p ≤ 30, assign a high weight value to the weight distribution function related to the optical power: 295 < B(x, y) < 305.

4. The design method of a multi-axis progressive ring focus lens according to claim 1, characterized in that: The value range of the width adjustment factor a of the central fixed-focus area is: 15 < a < 20.

5. The design method of a multi-axis progressive ring focus lens according to claim 1, characterized in that: The value range of the progressive optical power adjustment factor b is: 20 < b < 25.

6. A multi-axis progressive annular focus lens obtained by the design method according to claim 1.

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