Progressive addition lens and manufacturing method therefor

Abstract

A progressive addition lens and a manufacturing method therefor. The progressive addition lens (100) comprises a progressive surface. The progressive surface successively comprises, from an optical axis center O of the progressive addition lens (100) outward, three concentric circles, which are respectively a distance vision zone (121), a progressive zone (122) and a near vision zone (123) of the progressive surface. The distance vision zone (121), the progressive zone (122) and the near vision zone (123) respectively comprise a distance‑vision arc segment (301), a progressive arc segment (302) and a near‑vision arc segment (303) which are sequentially connected end‑to‑end. The radius of curvature of the distance‑vision arc segment (301) is a first radius, the radius of curvature of the near‑vision arc segment (303) is a second radius, and the radius of curvature of the progressive arc segment (302) gradually decreases from the first radius to the second radius. The centers of curvature of the distance‑vision arc segment (301), the progressive arc segment (302) and the near‑vision arc segment (303) are all located on an optical axis (130) of the progressive addition lens (100).

Description

Progressive eyeglass lenses and their preparation methods Technical Field

[0001] This disclosure relates to the field of spectacle lens technology, and more specifically, to a progressive spectacle lens and a method for preparing the same. Background Technology

[0002] As the flexibility of the eye's lens deteriorates with age, it becomes difficult for the eye to focus on near objects. This phenomenon is called presbyopia, and it is the most common vision problem among middle-aged and elderly people. The purpose of progressive lenses is to allow presbyopia patients to enjoy a clear and smooth field of vision from far to near without image jumps when wearing lenses.

[0003] Progressive lenses in related technologies combine multiple focal points and powers, divided into three visual zones from top to bottom: the distance vision zone, the progressive vision zone, and the near vision zone. To achieve a continuous change in curvature along the lens's meridian, progressive lenses concentrate astigmatism in the peripheral distortion zone (also called the blind spot, astigmatism zone, or deformed zone). Lens design primarily focuses on the design of meridional power, contour distribution, and progressive channel width. While meeting the above basic usage requirements, the design aims to minimize the astigmatic gradient change in the peripheral deformed zone, achieving a smooth lens surface. Many methods have been developed for studying meridional and contour distribution, such as the average curvature flow method and the non-uniform rational B-spline surface method. These methods have all achieved good results for progressive lenses.

[0004] However, no matter how hard they try, progressive lenses using the aforementioned technologies cannot completely avoid the presence of distortion zones on the lens. Because the astigmatism in these distortion zones is severe, it is unusable for vision and can even cause discomfort such as dizziness. Therefore, optimizing the astigmatism in the distortion zones to provide a better visual experience has become one of the key issues in designing progressive lenses. Summary of the Invention

[0005] This disclosure provides a progressive lens, which includes a progressive surface. The progressive surface comprises three concentric circles extending outward from the optical axis center of the progressive lens, representing a distance vision zone, a progressive zone, and a near vision zone. Each of the distance vision zone, the progressive zone, and the near vision zone includes a distance vision arc, a progressive arc, and a near vision arc connected end-to-end. The radius of curvature of the distance vision arc is a first radius; the radius of curvature of the near vision arc is a second radius; the radius of curvature of the progressive arc gradually decreases from the first radius to the second radius; the centers of the radii of curvature of the distance vision arc, the progressive arc, and the near vision arc are all located on the optical axis of the progressive lens.

[0006] This disclosure provides a method for manufacturing a progressive spectacle lens, comprising: providing a progressive surface. The progressive surface comprises three concentric circles extending outward from the optical axis center of the progressive spectacle lens, representing a distance vision zone, a progressive zone, and a near vision zone; the distance vision zone, the progressive zone, and the near vision zone each comprise a distance vision arc, a progressive arc, and a near vision arc connected end-to-end; the radius of curvature of the distance vision arc is a first radius; the radius of curvature of the near vision arc is a second radius; the radius of curvature of the progressive arc gradually decreases from the first radius to the second radius; the centers of the radii of curvature of the distance vision arc, the progressive arc, and the near vision arc are all located on the optical axis of the progressive spectacle lens. Attached Figure Description

[0007] Figure 1 is a schematic diagram of a progressive spectacle lens according to an exemplary embodiment of the present disclosure.

[0008] Figure 2 is a schematic diagram of the progressive surface of a progressive eyeglass lens according to an exemplary embodiment of the present disclosure.

[0009] Figure 3 is a schematic diagram of a generatrix used to form an asymptotic surface according to an exemplary embodiment of the present disclosure.

[0010] Figure 4 is a schematic diagram of the formation of the progressive arc segment in the busbar of an exemplary embodiment of the present disclosure.

[0011] Figure 5 is a schematic diagram of the far-view arc and the progressive arc in the busbar of an exemplary embodiment of the present disclosure. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this disclosure more apparent, exemplary embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same elements throughout. It should be understood that the embodiments described herein are merely illustrative and should not be construed as limiting the scope of this disclosure.

[0013] In this disclosure, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise expressly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0014] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0015] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

[0016] Figure 1 is a schematic diagram of a progressive spectacle lens according to an exemplary embodiment of the present disclosure.

[0017] The progressive lenses in this embodiment, also known as multifocal progressive lenses, are special lenses that correct vision at different distances (far, intermediate, and near) on the same lens. They replace single-vision or bifocal lenses by gradually changing the power on the lens surface, making them suitable for people who need to see clearly at multiple distances simultaneously (such as presbyopic patients).

[0018] As shown in Figure 1, the progressive lens 100 provided in this embodiment includes a convex surface 110 (the surface of the progressive lens facing an external object when worn normally) and a concave surface 120 (the side of the progressive lens facing / closer to the human eye when worn normally).

[0019] In most common lens types, such as single-vision lenses and regular progressive lenses, when people wear glasses normally, the convex side of the lens generally faces outwards, that is, the side facing the external environment, while the concave side faces the eye, being the inner surface close to the eye. This is because the convex side is more conducive to the initial refraction and scattering control of light, and it also conforms more to people's visual habits regarding eyeglass lenses. Furthermore, from a mechanical point of view, the convex side facing outwards can also enhance the lens's impact resistance to some extent.

[0020] In some lenses with special optical designs or specific functions, situations may arise that are the opposite of the norm. For example, some lenses designed to meet specific visual needs or special wearing methods may have the convex side as the inner surface and the concave side as the outer surface. For instance, some lenses used for special medical purposes or specific vision correction scenarios employ this unconventional design to better fit the shape of the eyeball or achieve specific optical effects. If the wearer uses a different wearing method than usual due to special reasons or needs, the inner and outer surfaces corresponding to the convex and concave sides of the lens will also change. For example, in some experimental wearing methods or temporary solutions for specific eye problems, the lens may be worn backwards, in which case the original convex side becomes the inner surface and the concave side becomes the outer surface.

[0021] In an exemplary embodiment, the progressive lens 100 includes a progressive surface. In this embodiment, the progressive surface refers to a specially designed area on the lens surface whose curvature continuously changes from the distance vision zone to the near vision zone, creating a smooth transition in multifocal function. This allows the wearer to see objects at different distances clearly without frequently changing glasses. The progressive surface is an important surface on the progressive lens that enables a gradual change in power. Its function is to allow the wearer to smoothly transition their vision from distant to near vision, avoiding noticeable visual jumps.

[0022] In an exemplary embodiment, the progressive surface may be the convex surface 110 of the progressive lens 100 or the concave surface 120 of the progressive lens 100.

[0023] In an exemplary embodiment, the progressive surface of the progressive lens 100 is the concave surface 120 of the progressive lens 100. In the following embodiments, the progressive surface of the lens is described as an inner progressive of the concave surface 120.

[0024] In this embodiment, the progressive surface can be designed as either a convex or concave surface of the lens. In practical applications, the lens is preferably an inwardly progressive concave surface. This is because the inwardly progressive concave design has some unique advantages. For example, from the perspective of wearing comfort, the concave design better conforms to the physiological structure of the human eye, reducing the interference of the lens on the skin around the eyes and the field of vision; from the perspective of optical performance, the inwardly progressive concave design helps to better control the refraction and scattering of light, making the power gradient more natural and smooth, effectively reducing aberrations and distortions, and providing the wearer with a clearer and more comfortable visual experience. In addition, the inwardly progressive setting helps to make the lens thinner.

[0025] In this embodiment of the present disclosure, the side of the progressive lens 100 opposite to the progressive surface is the vision-correcting surface. That is, when the concave surface 120 is the progressive surface, the convex surface 110 is the vision-correcting surface; when the convex surface 110 is the progressive surface, the concave surface 120 is the vision-correcting surface.

[0026] In this embodiment of the disclosure, the side opposite to the progressive surface is called the vision correction surface. Its main function is to correct the wearer's vision to meet different visual needs, such as correcting myopia, hyperopia, and astigmatism.

[0027] In an exemplary embodiment, the vision correction surface can be spherical or aspherical. A spherical vision correction surface has the same radius of curvature in all directions, providing basic vision correction, but may introduce some aberrations at the edges, affecting visual clarity and comfort. An aspherical vision correction surface, on the other hand, has different radii of curvature in different directions. This design allows for more precise vision correction, reduces aberrations, and provides a wider and clearer field of vision, especially in the peripheral areas of the lens, thus improving visual quality.

[0028] In an exemplary embodiment, the centers of the progressive surface and the vision-correcting surface are both on the same optical axis 130 (i.e., the horizontal dashed line in FIG1, which is also the X-axis in FIG3). For example, the point where the optical axis 130 intersects with the progressive surface is the optical axis center O, and it is assumed here that the progressive surface is a concave surface 120.

[0029] In this embodiment, the optical axis is a virtual axis passing through the center of the lens and perpendicular to the lens surface; it serves as the reference line for the lens's optical system. The centers of the progressive and refractive surfaces are both on the same optical axis. Only when the centers of both surfaces are on the same optical axis can light propagate along the designed path as it passes through the lens, allowing the progressive surface's power gradient function and the refractive surface's vision correction function to work accurately and synergistically. If the centers of the two surfaces are not on the same optical axis, it will cause deviations in the refraction and propagation of light, resulting in problems such as prismatic effects, causing dizziness, blurred vision, and other discomforts for the wearer, severely impacting wearing comfort and visual effects.

[0030] In an exemplary embodiment, the progressive surface comprises three concentric circles extending outward from the optical axis center of the progressive lens, which are respectively the distance vision zone, the progressive zone, and the near vision zone of the progressive surface.

[0031] As shown in Figure 2, this embodiment of the present disclosure proposes a distortion-free (deformation-free) toroidal progressive lens. Here, the concave surface 120 is taken as the progressive surface as an example. The progressive surface of the lens is divided into three areas, including the central distance vision area 121, the progressive area 122 of the connecting segment, and the peripheral near vision area 123.

[0032] In Figure 2, the intersection of the asymptotic surface's horizontal coordinate E1 and vertical coordinate E2 is the geometric center of the asymptotic surface, which coincides with the optical axis center O. The far-field region 121 is a circle centered at O ​​with radius R1; the asymptotic region 122 is an annulus centered at O ​​with radius between R2 and R1; the near-field region 123 is an annulus centered at O ​​with radius between R3 and R2. Where R1 is less than R2, R2 is less than R3, and R1, R2, and R3 are all real numbers greater than 0.

[0033] The distance vision zone in this embodiment is mainly used to see distant objects. Its optical power is suitable for correcting refractive errors when the eye is looking at distant objects, such as myopia and hyperopia, so that the wearer can see distant scenery clearly. This zone is used for things like watching movies and reading road signs while driving.

[0034] The progressive zone in this embodiment is a key part of the lens that enables a smooth transition from one degree of vision correction to another. Unlike ordinary lenses that have only a single degree, the degree changes gradually within this zone to meet the wearer's visual needs at different distances, such as transitioning from clear vision at a distance to clear vision at close range.

[0035] In this embodiment of the disclosure, the near vision zone refers to the area used for viewing near objects when wearing multifocal glasses (such as progressive multifocal glasses). When the human eye views near objects, the lens of the eye needs to increase its curvature to increase refractive power so that the object can be clearly imaged on the retina. For people wearing multifocal glasses, the near vision zone is the specific area that helps the eye obtain appropriate refractive power when viewing near objects.

[0036] The progressive lens provided in this embodiment of the invention designs the progressive surface as three concentric circles, with these three concentric circles corresponding to the distance vision zone, the progressive vision zone, and the near vision zone from the inside out. This ensures that the progressive lens does not have a distortion zone, i.e., it does not have an astigmatic zone, and will not cause users to experience dizziness or other discomfort.

[0037] In an exemplary embodiment, the far-field region, the progressive region, and the near-field region each include a far-field arc, a progressive arc, and a near-field arc connected end to end in sequence.

[0038] In an exemplary embodiment, the radius of curvature of the far-viewing arc is a first radius; the radius of curvature of the near-viewing arc is a second radius; and the radius of curvature of the progressive arc gradually decreases from the first radius to the second radius. The first radius is greater than the second radius.

[0039] In an exemplary embodiment, the centers of the radii of curvature of the distance vision arc, the progressive vision arc, and the near vision arc are all on the optical axis of the progressive lens.

[0040] In an exemplary embodiment, a busbar is provided, which includes, from the center of the optical axis outward, the far-viewing arc, the progressive arc, and the near-viewing arc; the busbar is rotated around the center of the optical axis to form the progressive surface.

[0041] Figure 3 illustrates the method for constructing the progressive curve / arc. As shown in Figure 3, the progressive surface of the lens proposed in this embodiment is formed by rotating a smooth generatrix around the center of the optical axis. That is, the generatrix in Figure 3 is rotated 360 degrees around the X-axis to obtain the progressive surface shown in Figure 2.

[0042] As shown in Figure 3, the generatrix is ​​divided into three segments, extending outward from the optical axis center O. These segments are the telephoto segment 301, and its radius of curvature is a constant value R. f (i.e., the first radius mentioned above); the asymptotic segment 302, composed of nanoscale scattered points (points on curve AB shown in Figure 3), wherein the radius of curvature of each point on this segment of the curve is R. f Gradually decrease to R n For example, along the optical axis center O from the inside out, there are two scattered points on curve AB with radii of curvature R and R respectively. i and R i ′, then R i Less than R f And greater than R i ′, R i ′ Less than R i And greater than R n The surrounding near segment 303 has a radius of curvature that is a constant R. n (That is, the second radius). On the progressive curve, the radius of curvature at each point gradually decreases according to a certain pattern from one end to the other. This means that the curvature of the progressive section changes gradually, and becomes increasingly curved. This change in the radius of curvature is closely related to the change in lens power, because the lens power is related to the curvature of the lens surface. The gradual decrease in the radius of curvature leads to a gradual increase in the lens power on the progressive section, thus achieving a smooth transition from low power (such as distance vision) to high power (such as near vision). The entire generatrix is ​​smooth and continuous, and the center of the radius of curvature at any point lies on the optical axis X.

[0043] In an exemplary embodiment, the radius of curvature of the farsighted zone can be 176.66 mm or 530 mm. 176.66 mm is for lenses that correct myopia from 0 to 400 degrees. 530 mm is for lenses that correct myopia of 400 degrees or more. The radius of curvature of the nearsighted zone varies depending on the added power.

[0044] In this embodiment of the disclosure, in optics, the radius of curvature is a physical quantity used to describe the degree of curvature of a surface. For the lens of the eye or the lens of eyeglasses, the radius of curvature determines its refractive power. The smaller the radius of curvature, the more curved the surface, the stronger the refractive power, and the greater the ability to refract light, and vice versa. This embodiment of the disclosure achieves a continuous transition of far, intermediate, and near optical powers by adjusting the radius of curvature in different regions.

[0045] In this embodiment of the disclosure, the additional power is the extra power added to meet near vision requirements, relative to the distance vision power. For example, a person needs -3.00D (300 degrees of myopia) glasses for distance vision, but may need an additional +2.00D for near vision; this +2.00D is the additional power. In the near vision zone of multifocal glasses, the radius of curvature of the lens is adjusted accordingly to provide different additional powers to meet different near vision needs. The larger the additional power, the smaller the radius of curvature of the near vision zone lens, and the more curved the lens surface, thus providing stronger refractive power to help the wearer see near objects clearly; conversely, the smaller the additional power, the larger the radius of curvature of the near vision zone lens, the less curved the lens, and the weaker the refractive power provided.

[0046] For example, a user with mild myopia who is starting to experience presbyopia may only need to wear -1.00D myopia lenses for distance vision, but requires an additional +1.50D of correction to see documents clearly up close. In their progressive multifocal glasses, the curvature radius of the near-vision lens would be designed based on this +1.50D correction, providing appropriate refractive power for near vision and ensuring objects are clearly focused on the retina.

[0047] In an exemplary embodiment, the progressive arc is a curve segment on an involute with a third radius as the base circle, and the radius of curvature of the curve is tangent to the base circle.

[0048] In an exemplary embodiment, the third radius satisfies the following formula:

[0049] Among them, R f R is the radius of curvature of the arc in the distance viewing segment. n Let d be the radius of curvature of the near-field arc. AB Let be the length of the curve AB.

[0050] In an exemplary embodiment, the x-coordinate and y-coordinate of any point P(x, y) on the curve AB are respectively:

[0051] Where θ is the roll angle.

[0052] An involute is the trajectory of a point on a moving straight line (generating line) that rolls purely along a fixed circle (base circle) on a plane. When the radius of this fixed circle is R0, it is called an involute with R0 as the base circle. Suppose there is a base circle with radius R0 fixed on a plane, and a straight line L is tangent to the base circle at point A. At this time, a point M on the straight line L coincides with point A. Let the straight line L roll along the base circle without slipping, that is, pure rolling. During the rolling process, the straight line L is always tangent to the base circle, and the point of tangency keeps changing. During the rolling process of the straight line L, the point M on the straight line L will move with the movement of the straight line L, and the path traversed by the point M is the involute with R0 as the base circle. In the Cartesian coordinate system, with the center of the base circle as the origin, the parametric equation of the involute can be expressed as the above formula (2), where θ is the rolling angle, which is the angle that the straight line L rotates from the initial position.

[0053] As shown in Figure 4, the asymptotic curve / arc 302 is a segment of curve AB on the involute 401 with R0 (third radius) as the base circle 402. The radius of curvature of each point on curve AB is tangent to the base circle 402 with R0 as the radius.

[0054] According to formulas (1) and (2) above, as long as Δθ (the preset rolling angle step size, the value of which is selected considering design and manufacturing accuracy, and this disclosure does not limit it) is used as the step size, all scattered points on curve AB can be obtained through iteration. Then, a smooth asymptotic curve can be obtained by connecting all scattered points with a spline curve.

[0055] Spline curves are constructed using piecewise polynomial functions to create smooth curves. Spline curves can include interpolation splines (where the curve passes through all scatter points) and approximation splines (where the scatter points only define the approximate shape of the curve). It's important to note that besides spline curves, there are several other methods to connect scatter points into a curve. For example, polynomial fitting. Specifically, a smooth curve is generated by approximating scatter points using polynomial functions (such as quadratic or cubic polynomials). Another example is spline interpolation (not a spline function), defining spline parameters (such as the number of nodes and smoothness). Yet another example is trend lines / smoothing algorithms. Specifically, a smooth curve can be generated by using a moving average method to calculate local means through a sliding window. Alternatively, Gaussian filtering / low-pass filtering can be used. Signal processing techniques (such as the smooth function) can be used to smooth the data. Yet another example is using parametric curves. For example, Bézier curves generate parametric curves from scatter points. B-spline curves, a generalized type of spline curve, support more flexible scatter point configurations.

[0056] In this embodiment of the disclosure, the arc length d of AB is... AB It varies depending on the added photodiode.

[0057] In an exemplary embodiment, the far-viewing arc and the progressive arc are tangentially continuous.

[0058] In an exemplary embodiment, the near-field arc and the progressive arc are tangentially continuous.

[0059] In this embodiment of the disclosure, the tangents of two connected curves are tangent continuous, meaning that the tangents of the two curves at the connection point are continuous. That is, the tangents of the two curves at the connection point have the same direction and slope, allowing for a smooth transition between the two curves without obvious bends or abrupt changes. For a curve, a straight line can be drawn at a certain point on the curve. This straight line intersects the curve only once at that point and closely follows the curve's direction in the vicinity of that point. This straight line is the tangent of the curve at that point. It represents the local direction of the curve at that point. When two curves are connected, if they are tangent continuous, then at the connection point, the tangents of the two curves are the same straight line. In other words, when smoothly transitioning from one curve to another, there is no sudden change in direction at the connection point, resulting in a very smooth curve without abrupt turns.

[0060] Figure 5 is a schematic diagram of the far-viewing arc and the progressive arc in the generatrix of an exemplary embodiment of this disclosure. As shown in Figure 5, the far-viewing curve / arc 301 and the progressive curve / arc 302 are tangentially continuous. That is, at the connection point (point A), the two curves have the same radius of curvature in both magnitude and direction, and the latter curve is tangent to the former curve at that point. Similarly, the near-viewing curve is also tangentially continuous with the progressive curve. That is, the curves of the generatrix are tangentially continuous with each other.

[0061] This disclosure addresses the problem of astigmatism within the deformation zone of progressive lenses affecting vision and wearing comfort in related technologies. It proposes a distortion-free nanometer (where nanometer refers to the distance between the scattered points in the progressive segment having nanometer-level precision) circular variable curvature (meaning the generatrix has variable curvature, and the progressive surface is formed by rotating this generatrix 360 degrees around the optical axis center). The progressive surface of this lens is formed by rotating a smooth, segmented, continuously variable curvature generatrix. This generatrix is ​​divided into three regions extending outward from the center point. The first region has a curvature radius of R. f The first region is the arc of the far-field region; the second region is a smooth curve with continuously varying curvature, where the radius of curvature gradually decreases at each point, called the asymptotic region, and this curve is tangentially continuous with the arc of the far-field region; the third region is a curve with a radius of curvature of R. n The arc, called the near vision zone, is tangentially continuous with the progressive zone curve. Therefore, this disclosure proposes a distortion-free nano-annular progressive spectacle lens.

[0062] Furthermore, this disclosure also provides a method for manufacturing a progressive lens, comprising: providing a progressive surface. The progressive surface comprises three concentric circles extending outward from the optical axis center of the progressive lens, namely a distance vision zone, a progressive zone, and a near vision zone; the distance vision zone, the progressive zone, and the near vision zone each comprise a distance vision arc, a progressive arc, and a near vision arc connected end-to-end; the radius of curvature of the distance vision arc is a first radius; the radius of curvature of the near vision arc is a second radius; the radius of curvature of the progressive arc gradually decreases from the first radius to the second radius; the centers of the radii of curvature of the distance vision arc, the progressive arc, and the near vision arc are all on the optical axis of the progressive lens.

[0063] In an exemplary embodiment, providing a progressive surface includes: providing a generatrix, the generatrix including, from the center of the optical axis outwards, the far-viewing arc, the progressive arc, and the near-viewing arc; and rotating the generatrix around the center of the optical axis to form the progressive surface.

[0064] In an exemplary embodiment, an asymptotic surface is provided, comprising: iteratively obtaining scatter points of the asymptotic arc segment with a preset rolling angle step size; and connecting the scatter points with a spline curve to obtain the asymptotic arc segment.

[0065] In an exemplary embodiment, the distance between the scattered points of the progressive arc is on the nanometer scale.

[0066] In this embodiment, on the one hand, the progressive surface / progressive lens adopts a rotationally symmetrical torus surface to eliminate astigmatism. All areas of the lens are usable for vision from far to near, eliminating the problem of distortion zones affecting visual field and wearing comfort. By rationally allocating the sizes of the distance vision zone, progressive zone, and near vision zone, both wearing comfort and clear vision from far to near are considered. The sizes of the distance vision zone, progressive zone, and near vision zone can differ depending on the intended use. For example, if the progressive lens is mainly used for daily life, the near vision zone is relatively larger. If the progressive lens is used while driving, the distance vision zone is larger. On the other hand, to address the issue of optical power distribution in the progressive zone, a continuous variable curvature method for the progressive segment is proposed. This method uses the involute as the baseline of the progressive segment, iteratively obtaining the scattered points of the curve with a step size of Δθ. Finally, a spline curve is used to connect the scattered points to form a smooth curve, ensuring that the radius of curvature at each point on the curve continuously changes from R... f Gradually decrease to R n Furthermore, this disclosure also provides a method for connecting different functional areas. By using different functional segments of the rotating busbar, curves or arcs in different areas of the busbar are smoothly connected in a tangentially continuous manner, so that when different areas are connected, there are no visible boundaries between the far-field, progressive, and near-field areas.

[0067] In this embodiment, astigmatism refers to the difference in refractive power of the eye in different directions, causing light rays to not focus on a single point, but instead forming two focal lines. This results in varying clarity of objects in different directions, leading to blurry or distorted vision. For example, some people see vertical lines clearly but horizontal lines blurry; this may be due to astigmatism. The progressive lenses provided in this embodiment use a rotationally symmetrical torus surface to solve the astigmatism problem. This torus surface has different radii of curvature in different meridian directions. By precisely designing the shape and parameters of the torus surface, it can refract and converge light rays in different directions to varying degrees, thereby refocusing light rays that could not originally focus on the same point, achieving the purpose of eliminating astigmatism. Furthermore, because it is rotationally symmetrical, its optical performance in all directions has a certain regularity and consistency, ensuring good visual effects when viewed from different angles.

[0068] This disclosure, through a progressive segment curvature design method, a method for continuous connection of different functional areas, and a distribution of functional areas on an annular surface, can further improve lens comfort. The progressive spectacle lens and its fabrication method provided in this disclosure can be applied to the design of progressive spectacle lenses for optometry.

Claims

1. A progressive lens, comprising a progressive surface; wherein, The progressive surface comprises three concentric circles extending outward from the optical axis center of the progressive lens, which are the distance vision zone, the progressive zone, and the near vision zone of the progressive surface, respectively. The far-field region, the progressive region, and the near-field region each include a far-field arc, a progressive arc, and a near-field arc connected end to end in sequence; The radius of curvature of the far-field arc is a first radius; the radius of curvature of the near-field arc is a second radius; the radius of curvature of the progressive arc gradually decreases from the first radius to the second radius; The centers of the radii of curvature of the distance vision arc, the progressive vision arc, and the near vision arc are all on the optical axis of the progressive lens.

2. The progressive spectacle lens as described in claim 1, wherein, The asymptotic arc is a curve segment on an involute with a third radius as the base circle, and the radius of curvature of the curve is tangent to the base circle.

3. The progressive spectacle lens as described in claim 2, wherein, The third radius satisfies the following formula: Among them, R f R is the radius of curvature of the arc in the distance viewing segment. n Let d be the radius of curvature of the near-field arc. AB Let be the length of the curve AB.

4. The progressive spectacle lens as described in claim 3, wherein, The x-coordinate and y-coordinate of any point P on curve AB are: Where θ is the roll angle.

5. The progressive spectacle lens as described in claim 1, wherein, The arc of the distance viewing segment and the arc of the progressive segment are tangentially continuous.

6. The progressive spectacle lens as claimed in claim 1, wherein, The near-field arc and the progressive arc are tangentially continuous.

7. The progressive spectacle lens as claimed in claim 1, wherein, The progressive surface is either the convex or concave surface of the progressive lens.

8. The progressive spectacle lens as claimed in claim 1, wherein, The progressive surface is the concave surface of the progressive lens.

9. The progressive spectacle lens as claimed in claim 1, wherein, The progressive lens also includes a vision correction front, which is spherical or aspherical.

10. The progressive spectacle lens as claimed in claim 9, wherein, The centers of the progressive surface and the vision-correcting surface are on the same optical axis.

11. A method for preparing a progressive spectacle lens, comprising: Provides asymptotic surfaces; The progressive surface comprises three concentric circles extending outward from the optical axis center of the progressive lens, representing the distance vision zone, the progressive zone, and the near vision zone. Each of these zones includes a sequentially connected arc segment for distance vision, an arc segment for progressive vision, and an arc segment for near vision. The radius of curvature of the arc segment for distance vision is a first radius; the radius of curvature of the arc segment for near vision is a second radius; the radius of curvature of the arc segment for progressive vision gradually decreases from the first radius to the second radius; and the centers of the radii of curvature of the arc segments for distance vision, progressive vision, and near vision are all located on the optical axis of the progressive lens.

12. The method of claim 11, wherein, Provides asymptotic surfaces, including: A busbar is provided, which includes, from the center of the optical axis outward, the far-viewing arc, the progressive arc, and the near-viewing arc in sequence; The generatrix is ​​rotated around the center of the optical axis to form the asymptotic surface.

13. The method of claim 11, wherein, Provides asymptotic surfaces, including: The scattered points of the progressive arc are obtained iteratively using a preset rolling angle step size; The asymptotic arc is obtained by connecting the scattered points with a spline curve.

14. The method of claim 13, wherein, The distance between the scattered points of the progressive arc is on the nanometer scale.

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