Spectacle lens and design method thereof

Abstract

Provided are eyeglass lenses and related technologies, wherein a wavelength is set to λ, a ratio of a total area of ​​defocused regions to an overall area of ​​a portion of the eyeglass lens provided with a plurality of defocused regions when viewed from above is set to r, an amount of travel of a wavefront in each defocused region relative to a base region is set to w, an average value of cos(2πw / λ) in one defocused region is obtained in each of the plurality of defocused regions, a total average of the plurality of such average values ​​is set to c(λ), an average value of sin(2πw / λ) in one defocused region is obtained in each of the plurality of defocused regions, a total average of the plurality of such average values ​​is set to s(λ), and f(λ) is set to {1‑r+r·c(λ)} 2 +{s(λ)} 2 When the wavelength λ is increased within the range of 0.45μm≦λ≦0.65μm, the sign of {f(λ×1.01)‑f(λ)} is reversed one or more times.

Description

Technical Field

[0001] The invention relates to a spectacle lens and a design method thereof. Background Art

[0002] As a spectacle lens for suppressing the development of refractive errors such as myopia, there is a spectacle lens in which a plurality of island-shaped areas having a positive refractive power compared to the prescribed refractive power are formed (for example, see Patent Document 1). Hereinafter, these island-shaped areas are referred to as defocus areas.

[0003] According to the eyeglass lens of this structure, among the light beams incident from the surface on the object side and emitted from the surface on the eyeball side, the light beams passing through the area outside the defocused area are focused on the wearer's retina, but the light beams passing through the defocused area are focused at a position forward of the retina, thereby suppressing the progression of myopia.

[0004] In this specification, the front direction where an object to be visually recognized exists in the optical axis direction is referred to as the near side, and the opposite direction to the near side and the direction from the rear in the optical axis direction, that is, the direction toward the depth of the eyeball from the eyeglass lens is referred to as the back side.

[0005] Patent Document 1 describes that, in a region formed by a mixture of a second refractive region (defocusing region) and a first refractive region (base region for achieving the prescribed refractive power), the combined area of ​​the second refractive region accounts for 20 to 60% of the combined area of ​​the second and first refractive regions. It is described that this ensures the function of suppressing the progression of myopia while maintaining sufficient visibility and providing a good wearing experience.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: U.S. Patent Application Publication No. 2017 / 0131567. Summary of the Invention

[0009] Problems to be solved by the invention

[0010] Patent Document 1, based on the technical concept that the defocused area is responsible for suppressing myopia progression, while the base area is responsible for visibility, teaches setting the area ratio of the defocused area to the base area to achieve both functions. Specifically, the ratio of the "spot intensity formed on the retina" to the "sum of the spot intensities formed at the focal point of the defocused area" is equivalent to the ratio of the base area to the defocused area.

[0011] According to the research conducted by the present inventors, it was found that visibility, which should be assumed by the base area, is also affected by the defocused area.

[0012] Specifically, it was found that the amount of light at the spot when the light beam passing through the base area focuses on the wearer's retina is affected by the area of ​​the defocused area and the height of the defocused area (the micro-convex portion referred to in Patent Document 1) relative to the base shape.

[0013] Throughout this specification, "spot" refers to the range from the peak to the first dark ring in the distribution of light from an object point, formed on the retina by passing through a portion of the spectacle lens and the eye's optical system. Furthermore, the sum of the energy within this range is referred to as "spot intensity." However, since "spot intensity" is generally proportional to the peak intensity of the spot, peak intensity will be used in some discussions instead of spot intensity.

[0014] Hereinafter, the “light spot when it is at the focal point of the basal region and focused on the wearer's retina” will also be referred to as the “light spot at the focal point of the basal plane”.

[0015] The “height of the convex region” is also referred to as the “SAG amount.” The SAG amount refers to the maximum distance of the defocused region from the tangent plane of the base region when there is no defocused region (convex region or concave region described later) (for example, the distance from the tangent plane to the vertex of the convex region or concave region).

[0016] The fact that the spot intensity at the focal point of the basal plane is affected by the SAG amount means that the spot intensity at the focal point of the basal plane is affected by the incident direction of the light beam. This is because when the light beam is incident at an angle (i.e., when the wearer is viewing the light from a peripheral perspective rather than directly), the distance the light beam travels increases, and its contribution to the propagation of the wavefront increases. This increase is called the "apparent SAG amount." When the light beam is incident at an angle, it is affected in the same way as when the SAG amount is changed.

[0017] Figure 1 This is a graph showing the relationship between the incident angle θ of the light beam (horizontal axis: unit [degree]) and the ratio of the apparent SAG amount / SAG amount (vertical axis).

[0018] Figure 2 This is a coordinate graph showing the relationship between the size (horizontal axis: unit [mm]) of the light beam passing through the base area in the eyeglass lens under the conditions of Example 1 described later when the focus position on the wearer's retina is zero, and the intensity ratio (vertical axis) when the spot intensity at the focus of the base surface is 1 when no defocused area is formed.

[0019] like Figure 1As shown in Figure 1, when a light beam is obliquely incident from a medium with a refractive index of 1 to a medium with a refractive index of N, the apparent SAG amount (hereinafter referred to as "SAG amount") is (N cos θ' - cos θ) / (N - 1) times the actual SAG amount. θ is the incident angle of the light beam, and θ' is the exit angle of the light beam. For example, at an incident angle of 30 degrees, the apparent SAG amount is 1.1 times greater than the actual SAG amount.

[0020] In actual design, the SAG amount is set so that the apparent SAG amount reaches a desired value at the incident angle during standard use (hereinafter referred to as the standard incident angle). The apparent SAG amount at this standard incident angle is referred to as the "standard apparent SAG amount." For example, if the "standard apparent SAG amount" is set at an incident angle of 30 degrees, the apparent SAG amount when used at an incident angle of 0 degrees will be 10% less than the "standard apparent SAG amount."

[0021] Figure 2 The dotted line is a coordinate graph when no convex region is provided. By providing the convex region, the spot intensity is reduced to the solid line (design value).

[0022] Figure 2 The dashed line represents the simulation result of the spot intensity distribution when the incident light is at 30 degrees. Figure 2 The dashed line represents the simulation result of the spot intensity distribution when the incident angle is 0 degrees, with a 10% reduction. Furthermore, since the design is based on a standard incident angle of 30 degrees, the apparent SAG amount at a 0-degree incident angle is 10% less than the standard apparent SAG amount. This confirms the difference in spot intensity between the two.

[0023] Furthermore, if a hard coat is formed on the convex region, the convex region is made uniform, resulting in a tendency to reduce the SAG amount compared to the base region also formed with a hard coat. Even in this case, the spot intensity at the focal point of the base surface will also change.

[0024] In any case, if Figure 2 As shown, the inventors' research revealed that the spot intensity at the focus of the base plane is affected by the actual SAG amount or the apparent SAG amount of the defocused area.

[0025] Keeping the SAG amount constant in the defocused area means simply limiting the incident angle of the light beam to a standard angle and maintaining the SAG amount precisely as designed even after the hard coating is formed. This is not a realistic measure.

[0026] An object of one embodiment of the present invention is to provide a technique that makes the spot intensity at the focus of the substrate less susceptible to changes in the SAG amount of the defocused area.

[0027] Means for solving problems

[0028] A first embodiment of the present invention is a spectacle lens comprising: a base region that primarily functions to cause a light beam incident from an object-side surface to be emitted from an eyeball-side surface and converged onto a retina via the eyeball; and a plurality of defocus regions that are in contact with the base region and primarily function to cause the light beam to converge on the near front side or the far back side of the retina, wherein a wavelength is λ, a ratio of a total area of ​​the defocus regions to an overall area of ​​a portion of the spectacle lens provided with the plurality of defocus regions when viewed from above is r, an amount of travel of a wavefront in each defocus region relative to the base region is w, an average value of cos(2πw / λ) in one defocus region is obtained in each of the plurality of defocus regions, a total average of the plurality of such average values ​​is c(λ), an average value of sin(2πw / λ) in one defocus region is obtained in each of the plurality of defocus regions, a total average of the plurality of such average values ​​is s(λ), and f(λ) is set to {1-r+r·c(λ)} 2 +{s(λ)} 2 When the wavelength λ is increased within the range of 0.45 μm≦λ≦0.65 μm, the sign of {f(λ×1.01)-f(λ)} is reversed one or more times.

[0029] A second aspect of the present invention is the aspect described in the first aspect, wherein the equation 1 is satisfied when λa=0.45 μm and λb=0.65 μm.

[0030] {f(λa×1.01)-f(λa)}×{f(λb×1.01)-f(λb)}<0···(Formula 1)

[0031] A third aspect of the present invention is the aspect according to the second aspect, wherein the equation 1 is satisfied when λa=0.50 μm and λb=0.60 μm.

[0032] A fourth aspect of the present invention is any one of the first to third aspects, wherein the ratio of minimum f(λ) / maximum f(λ) is 0.70 to 1.00 within the range of 0.45 μm≦λ≦0.65 μm.

[0033] A fifth aspect of the present invention is any one of the first to fourth aspects, wherein half or more of the plurality of defocused areas are arranged at the same period in a plan view.

[0034] A sixth aspect of the present invention is the aspect described in the fifth aspect, wherein more than half of the plurality of defocused areas are arranged in a hexagonal pattern.

[0035] A seventh aspect of the present invention is any one of the first to sixth aspects, wherein the spectacle lens is a myopia-suppressing lens or a hyperopia-suppressing lens.

[0036] An eighth aspect of the present invention is a method for designing a spectacle lens, the spectacle lens comprising: a base region that primarily functions to cause a light beam incident from a surface on the object side to be emitted from a surface on the eyeball side and converged onto a retina via the eyeball; and a plurality of defocus regions that are in contact with the base region and primarily function to cause the light beam to converge on the near front side or the far back side of the retina, wherein a wavelength is λ, a ratio of a total area of ​​the defocus regions to an overall area of ​​a portion of the spectacle lens provided with the plurality of defocus regions when viewed from above is r, an amount of travel of a wavefront in each defocus region relative to the base region is w, an average value of cos(2πw / λ) in one defocus region is obtained in each of the plurality of defocus regions, a total average of the plurality of such average values ​​is c(λ), an average value of sin(2πw / λ) in one defocus region is obtained in each of the plurality of defocus regions, a total average of the plurality of such average values ​​is s(λ), and f(λ) is set to {1-r+r·c(λ)} 2 +{s(λ)} 2 When the wavelength λ is increased in the range of 0.45 μm≦λ≦0.65 μm, the sign of {f(λ×1.01)-f(λ)} is inverted once or more.

[0037] Other aspects of the present invention that can be combined with the above aspects are as follows.

[0038] When the wavelength λ is increased in the range of 0.45 μm≦λ≦0.65 μm, the sign of {f(λ×1.01)-f(λ)} can be changed once or more (including positive or negative to zero).

[0039] Preferably, when the wavelength is 0.45 μm, the gradient of the graph becomes negative as the wavelength increases, and when the wavelength is 0.65 μm, the gradient of the graph reverses to positive as the wavelength increases.

[0040] The maximum absolute value of w / λ may be less than 2 (more reliably less than 1.5).

[0041] It can be a spectacle lens, which includes: a base area that causes a light beam incident from a surface on the object side to be emitted from a surface on the eyeball side and converged onto the retina through the eyeball; and a plurality of defocus areas, the plurality of defocus areas being defocus areas connected to the base area, the plurality of defocus areas having a property that a light beam passing through at least a portion of the defocus areas is incident on the retina as divergent light, the wavelength being λ, the ratio of the total area of ​​the defocus areas to the overall area of ​​the portion of the spectacle lens provided with the plurality of defocus areas when viewed from above being r, the amount of travel of the wavefront in each defocus area relative to the base area being w, an average value of cos(2πw / λ) in one defocus area being obtained in each of the plurality of defocus areas, a total average of the plurality of such average values ​​being c(λ), an average value of sin(2πw / λ) in one defocus area being obtained in each of the plurality of defocus areas, a total average of the plurality of such average values ​​being s(λ), and f(λ) being {1-r+r·c(λ)} 2 +{s(λ)} 2 When the wavelength λ is increased within the range of 0.45 μm≦λ≦0.65 μm, the sign of {f(λ×1.01)-f(λ)} is reversed one or more times.

[0042] Furthermore, the spectacle lens may satisfy at least one of the following conditions.

[0043] [Condition 1] When the wavelength λ is increased within the range of 0.45 μm≦λ≦0.65 μm, the sign of {f(λ×1.01)−f(λ)} is reversed one or more times.

[0044] [Condition 2] The wavelength range where {f(λ×1.01)−f(λ)}=0 is included within the range of 0.45 μm≦λ≦0.65 μm, and the ratio of minimum f(λ) / maximum f(λ) is 0.70 to 1.00.

[0045] The interval between the defocused areas may be 1.0 to 2.0 mm. In addition, the number of the defocused areas may be 100 to 100,000.

[0046] The diameter of the defocused area when viewed from above is preferably approximately 0.6 to 2.0 mm. The SAG (protrusion height, protrusion amount) of the defocused area is approximately 0.1 to 10 μm, preferably 0.4 to 2.0 μm. The radius of curvature of the convex area is approximately 50 to 250 mm, preferably spherical at approximately 86 mm.

[0047] There is no specific limitation on the defocusing power in each defocusing area. For example, the minimum defocusing power of the defocusing area on the eyeglass lens is preferably within the range of 0.5 to 4.5 D, and the maximum defocusing power is preferably within the range of 3.0 to 10.0 D. The difference between the maximum and minimum values ​​is preferably within the range of 1.0 to 5.0 D.

[0048] Effects of the Invention

[0049] According to one embodiment of the present invention, the intensity of the light spot at the focus of the substrate surface is not easily affected by the change of the SAG amount of the defocused area. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a graph showing the relationship between the incident angle θ of the light beam (horizontal axis: unit [degrees]) and the ratio of the apparent SAG amount / SAG amount (vertical axis).

[0051] Figure 2 This is a coordinate graph showing the relationship between the size (horizontal axis: unit [mm]) of the light beam passing through the base area in the eyeglass lens under the conditions of Example 1 when the focus position on the wearer's retina is zero, and the intensity ratio (vertical axis) when the spot intensity at the focus of the base surface when no defocused area is formed is set to 1.

[0052] Figure 3 This is a coordinate graph showing the change in the spot intensity f(λ) at the focus of the base plane (vertical axis: the spot intensity at the focus of the base plane normalized to 1 when assuming there is no defocused area) for the wavelength λ (horizontal axis: unit [μm]) in the eyeglass lens of Comparative Example 1.

[0053] Figure 4 This is a coordinate graph showing the change in the spot intensity f(λ) at the focus of the base plane (vertical axis: the spot intensity at the focus of the base plane normalized to 1 when assuming there is no defocused area) for wavelength λ (horizontal axis: unit [μm]) in the eyeglass lens of Comparative Example 2.

[0054] Figure 5 This is a coordinate graph showing the change in the spot intensity f(λ) at the focus of the base plane (vertical axis: the spot intensity at the focus of the base plane normalized to 1 when assuming there is no defocused area) for the wavelength λ (horizontal axis: unit [μm]) in the eyeglass lens of Example 1.

[0055] Figure 6 This is a coordinate graph showing the change in the spot intensity f(λ) at the focus of the base plane (vertical axis: the spot intensity at the focus of the base plane normalized to 1 when assuming there is no defocused area) for the wavelength λ (horizontal axis: unit [μm]) in the eyeglass lens of Example 2.

[0056] Figure 7 This is a schematic diagram of a portion of the spectacle lens of Comparative Example 1, in which a defocused area (black in the figure) is formed, when viewed from above.

[0057] Figure 8This is a schematic diagram of a portion of the spectacle lens of Comparative Example 2, in which a defocused area (black in the figure) is formed, when viewed from above.

[0058] Figure 9 This is a schematic diagram of a portion of the spectacle lens of Example 1, in which a defocused area (black in the figure) is formed, when viewed from above.

[0059] Figure 10 This is a schematic diagram of a portion of the spectacle lens of Example 2, in which a defocused area (black in the figure) is formed, when viewed from above. DETAILED DESCRIPTION

[0060] The following describes an embodiment of the present invention. The following description based on the accompanying drawings is illustrative, and the present invention is not limited to the illustrative schemes. The contents not recorded in this specification are all the contents recorded in Patent Document 1, and the contents not recorded in Patent Document 1 (especially those related to the manufacturing method) are all the contents recorded in WO2020 / 004551. In the event of any inconsistency between the contents of Patent Document 1 and the contents of the gazette, the records in the gazette shall take precedence.

[0061] The spectacle lenses described in this specification have an object-side surface and an eyeball-side surface. The "object-side surface" refers to the surface that faces the object when the wearer wears the glasses having the spectacle lens. The "eyeball-side surface" is the opposite, meaning the surface that faces the eye when the wearer wears the glasses having the spectacle lens. This relationship also applies to the lens substrate that forms the basis of the spectacle lens. That is, the lens substrate also has an object-side surface and an eyeball-side surface.

[0062] In this specification, "to" means a value greater than or equal to a predetermined value and less than or equal to a predetermined value.

[0063] <Spectacle lenses>

[0064] One aspect of the present invention relates to a spectacle lens comprising: a base region primarily responsible for causing a light beam incident from an object-side surface to exit from an eyeball-side surface and converge onto the retina through the eyeball; and a plurality of defocus regions, which are adjacent to the base region and primarily responsible for converging the light beam near or behind the retina. The term "primarily" is used because, in the spectacle lens according to one aspect of the present invention, the base region and the defocus regions do not function completely independently, for example, due to the use of diffraction phenomena.

[0065] The so-called base region is a portion that can realize the shape of the wearer's prescribed refractive power from the viewpoint of geometrical optics, and is a portion corresponding to the first refractive region of Patent Document 1.

[0066] The so-called defocused area is an area in which at least a part of the area does not converge to the focusing position based on the base area from the perspective of geometric optics. The defocused area is a portion equivalent to the tiny convex portion of Patent Document 1. The spectacle lens involved in one embodiment of the present invention is a lens for inhibiting the progression of myopia, similar to the spectacle lens described in Patent Document 1. Similar to the tiny convex portion of Patent Document 1, the multiple defocused areas involved in one embodiment of the present invention only need to be formed on at least one of the object-side surface and the eyeball-side surface of the spectacle lens. In this specification, the case where multiple defocused areas are provided only on the object-side surface of the spectacle lens is mainly exemplified. In the following, unless otherwise specified, the case where the defocused area is a convex area is exemplified.

[0067] As in Patent Document 1 Figure 10 As described above, a defocused area can be formed in the central portion of the eyeglass lens, or as described in Patent Document 1, Figure 1 As described above, the defocused area may not be formed in the central portion of the spectacle lens. In one embodiment of the present invention, an example is given in which the defocused area is not formed in the central portion of the spectacle lens.

[0068] The term "center of a spectacle lens" refers to the geometric center, optical center, or coring center of the spectacle lens, and its vicinity. This specification illustrates the coring center and its vicinity. This coring center is also referred to as the lens center. This specification illustrates the lens center when the wearer is looking straight ahead.

[0069] Furthermore, one aspect of the present invention satisfies the following conditions.

[0070] Let the wavelength be λ, let r be the ratio of the total area of ​​the defocused areas to the entire area of ​​the portion of the eyeglass lens provided with the plurality of defocused areas when viewed from above, let w be the amount of travel of the wavefront in each defocused area relative to the base area, obtain an average value of cos(2πw / λ) in one defocused area in each of the plurality of defocused areas, let c(λ) be the total average of the plurality of such average values, obtain an average value of sin(2πw / λ) in one defocused area in each of the plurality of defocused areas, let s(λ) be the total average of the plurality of such average values, and let f(λ) be {1-r+r·c(λ)} 2 +{s(λ)} 2 When λa=0.45 μm and λb=0.65 μm are set in Formula 1, Formula 1 is satisfied.

[0071] {f(λa×1.01)-f(λa)}×{f(λb×1.01)-f(λb)}<0···(Formula 1)

[0072] The denominator of the ratio r is the total area of ​​the eyeglass lens portion with multiple defocused areas when viewed from above. This total area is the area of ​​the annular portion enclosed by a circle with radius r1, where radius r1 extends to the defocused area closest to the lens center, and a circle with radius r2 extends to the defocused area farthest from the lens center. If a defocused area is formed at the center of the lens, this total area is the area of ​​the annular portion.

[0073] Around the central portion of the eyeglass lens, approximately circular defocused areas can be arranged in an island-like pattern (i.e., separated and not adjacent to each other) at equal intervals in the circumferential and axial directions. An example of how the defocused areas are arranged when viewed from above is to arrange them independently and discretely so that the centers of the defocused areas form the vertices of an equilateral triangle (the centers of the defocused areas are arranged at the vertices of a honeycomb structure). This arrangement is also known as a "hexagonal arrangement."

[0074] In this case, in order to simply obtain the ratio r, the seven defocused areas (one in the center and six around it) arranged in a hexagonal manner are converged as closely as possible to a perfect circle (for example, Figure 9 The area of ​​the perfect circle under the dotted line is regarded as the overall area, and the total area of ​​the defocused area can be regarded as the area of ​​seven defocused areas.

[0075] Furthermore, when adopting a configuration other than a hexagonal configuration, a configuration can be selected in which the number of defocused areas that converge most densely in a perfect circle is the largest among multiple defocused areas, and the area of ​​the perfect circle at this time is regarded as the overall area, and the total area of ​​the defocused areas contained in the perfect circle is regarded as the area of ​​the defocused areas.

[0076] As used herein, "wavefront" refers to the wavefront of a light beam passing through a spectacle lens and having a diameter defined by the pupil. The method for determining the amount of travel w of the wavefront in each defocused area relative to the base area is not particularly limited and can be performed, for example, through simulation processing using wave optics calculations.

[0077] By satisfying the conditions of Equation 1 above, the spot intensity at the focal point on the base plane is less susceptible to changes in the SAG amount in the defocused area. In other words, even if the SAG amount in the defocused area changes, the change in spot intensity at the focal point on the base plane is minimal (this property is also called "robustness"). The following describes the insights leading to this concept.

[0078] First, the spot intensity at the focal point of the base plane is examined. The method for obtaining the spot intensity is not limited, and the spot intensity can be evaluated using the PSF (Point Spread Function) using the ray tracing method.

[0079] Assuming the amount of wavefront travel at each defocused area relative to the base area is w, and the possible range of light coordinates (x, y) passing through the pupil is P, the spot intensity f(λ) at the focus of the base surface is expressed as follows.

[0080]

Mathematical formula 1

[0081]

[0082] In the base region, w = 0. At this point, cos(2πw / λ) is 1, and sin(2πw / λ) is 0. Next, decomposing the base region and the defocused region (letting the defocused region in the aforementioned P be Ps) creates the following equation. The brackets in the former right-hand side of the equation represent the integral value for the base region, while the brackets in the latter right-hand side represent the integral value for the defocused region.

[0083]

Mathematical formula 2

[0084]

[0085] The average value of cos(2πw / λ) in one defocused area is obtained in each of the multiple defocused areas, and the total average of the multiple average values ​​is defined as c(λ). The average value of sin(2πw / λ) in one defocused area is obtained in each of the multiple defocused areas, and the total average of the multiple average values ​​is defined as s(λ).

[0086] The average values ​​of cos(2πw / λ) and sin(2πw / λ) in a single defocused area (convex area) are calculated as quantities equivalent to the per-unit-area integral values ​​of cos(2πw / λ) and sin(2πw / λ), which vary slightly locally within the defocused area (convex area). The average values ​​of these two values ​​are also calculated for defocused areas other than the defocused area (convex area).

[0087] Then, by calculating the grand average of multiple average values ​​of cos(2πw / λ), c(λ), which is equivalent to the amount per unit area of ​​the integrated value of cos(2πw / λ) in multiple defocused areas, is obtained. By calculating the grand average of multiple average values ​​of sin(2πw / λ), s(λ), which is equivalent to the amount per unit area of ​​the integrated value of cos(2πw / λ) in multiple defocused areas, is obtained. Then, f(λ) is as follows.

[0088] f(λ)={1-r+r·c(λ)} 2 +{s(λ)} 2 (Formula 4)

[0089] In one embodiment of the present invention, for ease of explanation, an example is given in which the average value of cos(2πw / λ) of a defocused area (convex area) is equal to the total average value of cos(2πw / λ) of all defocused areas, and the average value of sin(2πw / λ) of a defocused area (convex area) is equal to the total average value of sin(2πw / λ) of all defocused areas.

[0090] Here, assuming that λ is multiplied by 1.01, the above formula 3 is as follows.

[0091]

Mathematical formula 3

[0092]

[0093] The expression within the integral of the above-mentioned formula 5 is equivalent to a state where w(x, y) is multiplied by 1 / 1.01 (see the following formula 6).

[0094]

Mathematical formula 4

[0095]

[0096] The absolute value of the travel distance w of the wavefront in each defocused area relative to the base area increases if the SAG amount increases because the distance the light beam passes through the defocused area becomes longer, and decreases if the SAG amount decreases.

[0097] That is, the trend of change in the spot intensity f(λ) at the focal point of the base plane due to changes in the amount of wavefront travel w in each defocused region relative to the base region (i.e., the SAG amount of the defocused region) is similar to the trend of change in the spot intensity f(λ) at the focal point of the base plane corresponding to changes in wavelength λ. One aspect of the present invention focuses on this similarity in trend and, by understanding the trend of change in the spot intensity f(λ) corresponding to changes in wavelength λ, understands the trend of change in the spot intensity f(λ) corresponding to changes in the SAG amount of the defocused region.

[0098] As a result, if the eyeglass lens has a small change in the spot intensity f(λ) at the focus of the base surface according to the change in wavelength λ, even if the SAG amount in the defocused area changes due to the oblique incidence of the light beam or the formation of a hard coating, the change in the spot intensity at the focus of the base surface becomes smaller.

[0099] As mentioned in the Examples section below, the present inventors have discovered that to reduce the change in the spot intensity f(λ) at the focal point of the basal plane due to changes in wavelength λ, the spot intensity f(λ) at the focal point of the basal plane should not be monotonically increased or decreased with respect to wavelength λ. This knowledge led to the creation of the above-mentioned Equation 1 (discussed below).

[0100] {f(λa×1.01)-f(λa)}×{f(λb×1.01)-f(λb)}<0···(Formula 1)

[0101] The above formula 1 means that the signs of the gradient of the spot intensity f(λa) at the focus of the base plane when the wavelength increases from wavelength λa and the gradient of the spot intensity f(λb) at the focus of the base plane when the wavelength increases from wavelength λb are opposite.

[0102] Figures 3 to 6 Coordinate graphs showing the changes in the light spot intensity f(λ) at the focus of the base surface (vertical axis: the peak intensity of the light spot at the focus of the base surface assuming no defocused area is normalized to 1) relative to the wavelength λ (horizontal axis: unit [μm]) of the eyeglass lenses of Comparison Example 1, Comparison Example 2, Example 1, and Example 2, respectively.

[0103] Figures 3 to 6 The solid line is the design value curve. Figures 3 to 6 The dotted line and Figure 2 Similarly, the dotted line is a curve showing a state where the apparent SAG amount is 10% smaller than the "standard apparent SAG amount" when the incident angle is set to 30 degrees and the light is used at an incident angle of 0 degrees.

[0104] Furthermore, when a hard coat is formed on the convex region, the convex region is made uniform, which tends to reduce the amount of SAG from the base region also formed with a hard coat. Even in this case, the spot intensity at the focal point of the base surface will also change.

[0105] If {f(λa×1.01)-f(λa)} in the above formula 1 is positive, it means that Figures 3 to 6 In the curves of the vertical and horizontal axes, if the wavelength increases, the gradient of the curve is positive. On the contrary, if {f(λa×1.01)-f(λa)} is negative, it means that Figures 3 to 6 In the curves of the vertical and horizontal axes, the gradient of the curve becomes negative as the wavelength increases.

[0106] That is, the above-mentioned formula 1 indicates that the gradient of the curve near the wavelength λa and the gradient of the curve near the wavelength λb are reversed in sign or at least one of the gradients becomes zero.

[0107] The change in the spot intensity f(λ) at the focus of the base surface (vertical axis: the spot intensity at the focus of the base surface assuming no defocused area is normalized to 1) relative to the wavelength λ (horizontal axis: unit [μm]) in the eyeglass lenses of Comparative Examples 1 and 2 described later is monotonically increasing or monotonically decreasing, so the degree of change is large.

[0108] On the other hand, in the eyeglass lenses of Examples 1 and 2 described below, which employ one embodiment of the present invention, the change in the spot intensity f(λ) at the focal point on the base plane relative to wavelength λ increases and then decreases, or decreases and then increases, as the wavelength increases. Therefore, the degree of change is smaller than in Comparative Examples 1 and 2.

[0109] In Examples 1 and 2 described below, Equation 1 is satisfied when λa = 0.45 μm and λb = 0.65 μm. More preferably, Equation 1 is satisfied when λa = 0.50 μm and λb = 0.60 μm. In practice, in Example 1, which satisfies this preferred setting, the spot intensity f(λ) at the focal point on the base plane changes very little even when the wavelength changes.

[0110] The reason for setting λa = 0.45 μm and λb = 0.65 μm is that these wavelengths represent the most sensitive region of the retina within the visible light wavelength range. Specifically, if λa = 0.50 μm and λb = 0.60 μm, the wavelength region with the highest sensitivity (0.55 μm) is sandwiched between them. In this case, if the sign of the gradient of the coordinate graph is reversed, the wavelength range of monotonically increasing or decreasing is narrower than when the gradient of the coordinate graph is reversed at λa = 0.45 μm and λb = 0.65 μm. As a result, according to one embodiment of the present invention, the degree of change in the spot intensity f(λ) at the focal point of the basal plane is reduced compared to a case where the intensity continues to monotonically increase or decrease within the aforementioned wavelength range.

[0111] <Preferred Examples and Modifications of Spectacle Lenses>

[0112] Hereinafter, preferred examples and modified examples of the spectacle lens in one embodiment of the present invention will be described.

[0113] More than half of the multiple defocused areas (all defocused areas) are preferably arranged with the same period when viewed from above. As an example of a pattern with the same period, the above-mentioned hexagonal arrangement can be cited. In the case of the above-mentioned hexagonal arrangement, the diffraction phenomenon can be preferably utilized, and the above-mentioned formula 1 can be satisfied. The direction of the period can be circumferential and / or radial. It is preferably 80% or more, more preferably 90% or more, and further preferably 95% or more. In the following, preferred examples of "more than half of the number of all defocused areas" are, as above, in the preferred order of 80%, 90% or more, and 95% or more, and repeated records are omitted.

[0114] The defocused areas may be spherical, aspherical, annular, or a mixture thereof (for example, the center of each defocused area may be spherical, and the peripheral area outside the center may be aspherical). However, it is preferred that at least half of the multiple defocused areas (all defocused areas) be arranged at the same period when viewed from above, and accordingly, the defocused areas are preferably convex areas of a spherical surface.

[0115] The spot intensity f(λ) at the focal point of the base plane is preferably such that the ratio of minimum f(λ) / maximum f(λ) is between 0.70 and 1.00 within the wavelength range of 0.45 to 0.65 μm. The spot intensity f(λ) at the focal point of the base plane is the value normalized to 1, assuming no defocused area. It should be noted that one aspect of the present invention is also valid even with this specification alone.

[0116] Furthermore, if the maximum absolute value of w / λ is less than 2 (more reliably less than 1.5), the spot intensity f(λ) has only one extreme value. In this state, the diffraction order is 1, and the extreme value is reached only at the reference wavelength. In this state, the minimum f(λ) / maximum f(λ) ratio can be between 0.70 and 1.00.

[0117] When the "standard apparent SAG amount" is set at an incident angle of 30 degrees, the apparent SAG amount when used at an incident angle of 0 degrees is set to be 10% smaller than the "standard apparent SAG amount" ( Figures 3 to 6 When the dashed line is shown, the ratio of minimum f(λ) / maximum f(λ) is preferably greater than 0.70.

[0118] The above formula 1 is not equal (i.e., "<"), but as another solution, it can also be a solution containing an equal sign (i.e., "≤"). That is, in this other solution, either {f(λa×1.01)-f(λa)} or {f(λb×1.01)-f(λb)} can be 0 in the wavelength range of 0.45 to 0.65 μm. This means that Figures 3 to 6 In the graphs with the vertical and horizontal axes, the spot intensity f(λ) at the focal point on the base plane remains constant even as the wavelength increases. Specifically, if f(λ) remains constant within the wavelength range of 0.45 to 0.65 μm, the degree of change in f(λ) is smaller than in the cases of continuous monotonous increase or monotonous decrease as shown in Comparative Examples 1 and 2 described below.

[0119] exist Figures 3 to 6 In the coordinate diagram of the vertical and horizontal axes, Figure 5 (Example 1), Figure 6As shown in Example 2, when the wavelength is 0.45 μm, the gradient of the graph becomes negative as the wavelength increases, and when the wavelength is 0.65 μm, the gradient of the graph preferably reverses to positive as the wavelength increases. On the other hand, when the wavelength is 0.45 μm, the gradient of the graph becomes positive as the wavelength increases, and when the wavelength is 0.65 μm, it is not ruled out that the gradient of the graph reverses to negative as the wavelength increases.

[0120] As a result, Equation 1 above implies a reversal of the sign of the gradient of the coordinate graph between wavelengths λa and λb. Expanding on this implication, the sign of {f(λ×1.01)-f(λ)} at wavelengths of 0.45μm and 0.65μm is either positive or negative. As long as the sign of {f(λ×1.01)-f(λ)} reverses multiple times as the wavelength λ increases within the range of 0.45 to 0.65μm, the effects of one embodiment of the present invention can be achieved. In other words, in this case, the degree of change in the spot intensity f(λ) at the focal point of the base plane is reduced compared to the cases of continuous monotonic increase or monotonic decrease shown in Comparative Examples 1 and 2 described below.

[0121] One aspect of the present invention is expressed in combination with the above-mentioned modified examples as follows.

[0122] "A spectacle lens comprising: a base region in which a light beam incident from a surface on the object side is emitted from a surface on the eyeball side and converges onto a retina via the eyeball; and a plurality of defocus regions, the plurality of defocus regions being defocus regions in contact with the base region, the plurality of defocus regions having a property in which a light beam passing through at least a portion of the defocus regions is incident on the retina as divergent light, wherein the wavelength is λ, the ratio of the total area of ​​the defocus regions to the entire area of ​​the portion of the spectacle lens provided with the plurality of defocus regions when viewed from above is r, the amount of travel of a wavefront at each defocus region relative to the base region is w, an average value of cos(2πw / λ) in one defocus region is obtained in each of the plurality of defocus regions, a total average of the plurality of such average values ​​is c(λ), an average value of sin(2πw / λ) in one defocus region is obtained in each of the plurality of defocus regions, a total average of the plurality of such average values ​​is s(λ), and f(λ) is set to {1-r+r·c(λ)} 2 +{s(λ)} 2 When the wavelength λ is increased within the range of 0.45 μm ≤ λ ≤ 0.65 μm, the sign of {f(λ×1.01)-f(λ)} changes one or more times (preferably, the sign is reversed).”

[0123] Here, the so-called "sign change" includes not only a sign reversal from positive to negative or from negative to positive, but also a change from a positive value to zero (i.e., no positive sign), a change from a negative value to zero, or a change from zero to a positive or negative value.

[0124] Furthermore, the spectacle lens may satisfy at least one of the following conditions.

[0125] [Condition 1] When the wavelength λ is increased within the range of 0.45 μm≦λ≦0.65 μm, the sign of {f(λ×1.01)−f(λ)} is reversed one or more times.

[0126] [Condition 2] The wavelength range where {f(λ×1.01)−f(λ)}=0 is included within the range of 0.45 μm≦λ≦0.65 μm, and the ratio of minimum f(λ) / maximum f(λ) is 0.70 to 1.00.

[0127] Furthermore, the "reversal of positive and negative" in Condition 1 also includes a case where the gradient changes from negative to zero to positive with increasing wavelength λ, with a wavelength range where the gradient is zero.

[0128] The value of 1.01 in {f(λ×1.01)-f(λ)} can be appropriately varied within the range of, for example, 1.001 to 1.1. However, if this value is too large, the understanding of the gradient change becomes rough, while if it is too small, the calculation takes time. Taking these considerations into account, the value is 1.01.

[0129] The technical concept of the spectacle lens 1 according to one embodiment of the present invention described above can also be applied to a spectacle lens 1 that functions to suppress hyperopia progression. Specifically, the defocused region is configured to converge the light beam at a position farther from the object than position A on the retina in the direction of light travel (i.e., further inward from position A). If the spectacle lens according to one embodiment of the present invention described so far is modified from "convex" to "concave" so that the light beam converges further inward from the predetermined position A, a spectacle lens that suppresses hyperopia progression (referred to as a hyperopia suppression lens) can be achieved.

[0130]

[0131] The arrangement of the plurality of defocused areas is not particularly limited and can be determined from the perspectives of, for example, external visibility of the defocused areas, design properties imparted by the defocused areas, and adjustment of refractive power by the defocused areas.

[0132] Around the central portion of the eyeglass lens, approximately circular defocused areas can be arranged in an island-like pattern (i.e., separated and not adjacent to each other) at equal intervals in the circumferential and radial directions. An example of the arrangement of the defocused areas when viewed from above is to arrange them independently and discretely, with the centers of the convex areas forming vertices of an equilateral triangle (hexagonal arrangement, with the centers of the defocused areas arranged at the vertices of a honeycomb structure). In this case, the spacing between the defocused areas can be 1.0 to 2.0 mm. Furthermore, the number of defocused areas can be 100 to 100,000.

[0133] Each defocused region is configured, for example, as follows. The diameter of the defocused region when viewed from above is preferably approximately 0.6 to 2.0 mm. The SAG (protrusion height, protrusion amount) of the defocused region is approximately 0.1 to 10 μm, preferably 0.4 to 2.0 μm. The radius of curvature of the convex region is 50 to 250 mm, preferably spherical at approximately 86 mm.

[0134] There is no specific limitation on the defocusing power in each defocusing area. For example, the minimum defocusing power of the defocusing area on the eyeglass lens is preferably within the range of 0.5 to 4.5 D, and the maximum defocusing power is preferably within the range of 3.0 to 10.0 D. The difference between the maximum and minimum values ​​is preferably within the range of 1.0 to 5.0 D.

[0135] "Defocus power" refers to the difference between the refractive power of each defocused area and the refractive power of the area outside of that area. In other words, the "defocus power" is the difference between the average of the minimum and maximum refractive powers at a given location within the defocused area, minus the refractive power of the base area. This specification illustrates the case where the defocused area is a convex area.

[0136] The "refractive power" in this specification refers to the average refractive power, which is the average of the refractive power in the direction a where the refractive power is the smallest and the refractive power in the direction b (a direction perpendicular to the direction a) where the refractive power is the largest.

[0137] <Spectacle lens design method>

[0138] The present invention is also applicable to a method for designing eyeglass lenses. Specifically, conditions are set to satisfy the above-mentioned equation 1 to design eyeglass lenses. Details of the various components of this design method are omitted here as they overlap with those described in "Eyeglass Lenses." Furthermore, the technical concepts of the present invention are also reflected in a method for manufacturing eyeglass lenses designed using this design method.

[0139] The technical scope of the present invention is not limited to the above-described embodiment, and includes various changes and improvements within the scope of the invention's constituent technical features and the specific effects achieved by their combination.

[0140] Example

[0141] Next, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the following examples.

[0142] Figures 7-10 These are schematic diagrams of portions of the spectacle lenses in which a defocused area (black in the figures) is formed, when viewed from above, in the spectacle lenses of Comparative Example 1, Comparative Example 2, Example 1, and Example 2, respectively.

[0143] (Comparative Example 1)

[0144] In this example, eyeglass lenses that meet the following conditions were tested.

[0145] Curvature radius: 131.1mm

[0146] Diameter of convex area: 0.972mm

[0147] SAG amount: 0.90μm

[0148] Distance between the centers of the convex areas (hexagonal arrangement spacing): 1.459mm

[0149] Wavefront travel distance w: 0.531 μm

[0150] Area ratio r: 0.40

[0151] The conditions other than those mentioned above are as follows. The following conditions apply to this example as well as the following examples.

[0152] A convex area is also formed in the center of the eyeglass lens.

[0153] The shape of the convex region is a spherical surface, and the arrangement of the convex region in a plan view is a hexagonal arrangement.

[0154] The area ratio r is obtained by assuming that the area of ​​a perfect circle in which seven defocused areas (one in the center and six around it) arranged in a hexagonal manner are most densely packed is the total area, and the total area of ​​the defocused areas is the area of ​​the seven defocused areas.

[0155] The prescription power S (spherical power) of the base area of ​​the spectacle lens is 0.00D, and the prescription power C (astigmatism power) is 0.00D.

[0156] The diameter of the eyeglass lens before spherical processing when viewed from above is 100 mm.

[0157] ·No hard coating is formed on the eyeglass lenses.

[0158] The refractive index of eyeglass lenses is 1.589.

[0159] The base curve of the base area is 3.30D.

[0160] The defocused area is formed within a circle with a radius of 17 mm from the center of the lens.

[0161] (Comparative Example 2)

[0162] In this example, eyeglass lenses that meet the following conditions were tested.

[0163] Curvature radius: 131.1mm

[0164] Diameter of convex area: 0.724mm

[0165] SAG amount: 0.50μm

[0166] Distance between the centers of the convex area (pitch of the hexagonal configuration): 0.937mm

[0167] Wavefront travel distance w: 0.295μm

[0168] Area ratio r: 0.55

[0169] (Example 1)

[0170] In this example, eyeglass lenses that meet the following conditions were tested.

[0171] Curvature radius: 131.1mm

[0172] Diameter of convex area: 0.887mm

[0173] SAG amount: 0.75μm

[0174] Distance between the centers of the convex areas (hexagonal arrangement spacing): 1.387mm

[0175] Wavefront travel distance w: 0.443 μm

[0176] Area ratio r: 0.38

[0177] (Example 2)

[0178] In this example, eyeglass lenses that meet the following conditions were tested.

[0179] Curvature radius: 131.1mm

[0180] Diameter of the convex area: 0.950mm

[0181] SAG amount: 0.86μm

[0182] Distance between the centers of the convex areas (hexagonal arrangement spacing): 1.448mm

[0183] Wavefront travel distance w: 0.507μm

[0184] Area ratio r: 0.39

[0185] In the case of Comparative Example 1, when λa=0.45μm and λb=0.65μm, the above formula 1 is not satisfied. Figure 3 As shown, in the design value ( Figure 3 In the solid line), when the "standard apparent SAG amount" is set at an incident angle of 30 degrees, the apparent SAG amount when used at an incident angle of 0 degrees is also 10% smaller than the "standard apparent SAG amount" ( Figure 3 As shown in the dashed line, as the wavelength λ increases, the spot intensity f(λ) at the focus of the substrate increases monotonically. Therefore, the degree of change in the spot intensity f(λ) at the focus of the substrate increases with changes in the wavelength λ.

[0186] In Comparative Example 2, when λa=0.45μm and λb=0.65μm, the above formula 1 is not satisfied. Figure 4 As shown, in the design value ( Figure 4 In the solid line), when the "standard apparent SAG amount" is set at an incident angle of 30 degrees, the apparent SAG amount when used at an incident angle of 0 degrees is also 10% smaller than the "standard apparent SAG amount" ( Figure 4 As shown in the dashed line, as the wavelength λ increases, the spot intensity f(λ) at the focal point of the substrate plane decreases monotonically. Therefore, the degree of change in the spot intensity f(λ) at the focal point of the substrate plane is large for changes in the wavelength λ.

[0187] In the case of Example 1, the above formula 1 is satisfied when λa=0.45μm and λb=0.65μm. Figure 5 As shown, in the design value ( Figure 5 In the solid line), when the "standard apparent SAG amount" is set at an incident angle of 30 degrees, the apparent SAG amount when used at an incident angle of 0 degrees is also 10% smaller than the "standard apparent SAG amount" ( Figure 5 As shown in the dashed line, as wavelength λ increases, the spot intensity f(λ) at the focal point on the basal plane decreases and then increases. In particular, in Example 1, Equation 1 is also satisfied when λa = 0.50 μm and λb = 0.60 μm. Therefore, both the solid and dashed lines show that the degree of change in the spot intensity f(λ) at the focal point on the basal plane associated with changes in wavelength λ is very small.

[0188] In the case of Example 2, the above formula 1 is satisfied when λa=0.45μm and λb=0.65μm. Figure 6 As shown, in the design value ( Figure 6In the solid line), when the "standard apparent SAG amount" is set at an incident angle of 30 degrees, the apparent SAG amount when used at an incident angle of 0 degrees is also 10% smaller than the "standard apparent SAG amount" ( Figure 6 As the wavelength λ increases, the spot intensity f(λ) at the focal point of the substrate decreases and then increases. Therefore, both the solid and dashed lines show a small change in the spot intensity f(λ) at the focal point of the substrate with changes in wavelength λ.

[0189] The above results show that, in each example, even if the SAG amount in the defocused area changes slightly, or even if the original design value of the SAG amount is changed, the degree of change in the spot intensity f(λ) at the focal point of the base plane can be reduced. In other words, it can be seen that in each example, the spot intensity f(λ) at the focal point of the base plane is not easily affected by changes in the SAG amount in the defocused area.

Claims

1. A spectacle lens comprising: The basement area has the function of causing a light beam incident from the surface on the object side to be emitted from the surface on the eyeball side and converge onto the retina through the eyeball; and A plurality of defocused areas, wherein the plurality of defocused areas are defocused areas connected to the base area, and the plurality of defocused areas have the function of converging the light beams on the near front side or the back side of the retina, Let the wavelength be λ, let r be the ratio of the total area of ​​the defocused regions to the entire area of ​​the portion of the eyeglass lens provided with the multiple defocused regions when viewed from above, let w be the amount of travel of the wavefront in each defocused region relative to the base region, and the unit of w is μm. The average value of cos(2πw / λ) in each of the plurality of defocused areas is obtained, and the total average of the plurality of average values ​​is set to c(λ). The average value of sin(2πw / λ) in one defocused area is obtained in each of the plurality of defocused areas, and the total average of the plurality of average values ​​is set to s(λ). When f(λ) is {1-r+r·c(λ)} 2 +{s(λ)} 2 When the wavelength λ is increased within the range of 0.45 μm≦λ≦0.65 μm, the sign of {f(λ×1.01)-f(λ)} is reversed one or more times, where the sign reversal is from positive to negative and from negative to positive.

2. The spectacle lens according to claim 1, wherein When λa=0.45μm and λb=0.65μm are set in Formula 1, Formula 1 is satisfied. {f(λa×1.01)-f(λa)}×{f(λb×1.01)-f(λb)}<0···(Formula 1).

3. The spectacle lens according to claim 2, wherein: In Formula 1, when λa=0.50 μm and λb=0.60 μm are set, Formula 1 is satisfied.

4. The spectacle lens according to any one of claims 1 to 3, wherein In the range of 0.45 μm≦λ≦0.65 μm, the ratio of minimum f(λ) / maximum f(λ) is 0.70 to 1.

00.

5. The spectacle lens according to any one of claims 1 to 3, wherein More than half of the plurality of defocused areas are arranged at the same period in a plan view.

6. The spectacle lens according to claim 5, wherein: More than half of the plurality of defocused areas are arranged in a hexagonal pattern.

7. The spectacle lens according to any one of claims 1 to 3, wherein The spectacle lenses are myopia progression inhibiting lenses or hyperopia progression inhibiting lenses.

8. A method for designing a spectacle lens, the spectacle lens comprising: The basement area has the function of causing a light beam incident from the surface on the object side to be emitted from the surface on the eyeball side and converge onto the retina through the eyeball; and A plurality of defocused areas, wherein the plurality of defocused areas are defocused areas connected to the base area, and the plurality of defocused areas have the function of converging the light beams on the near front side or the back side of the retina, Let the wavelength be λ, let r be the ratio of the total area of ​​the defocused regions to the entire area of ​​the portion of the eyeglass lens provided with the multiple defocused regions when viewed from above, let w be the amount of travel of the wavefront in each defocused region relative to the base region, and the unit of w is μm. The average value of cos(2πw / λ) in each of the plurality of defocused areas is obtained, and the total average of the plurality of average values ​​is set to c(λ). The average value of sin(2πw / λ) in one defocused area is obtained in each of the plurality of defocused areas, and the total average of the plurality of average values ​​is set to s(λ). When f(λ) is {1-r+r·c(λ)} 2 +{s(λ)} 2 When the wavelength λ is increased in the range of 0.45μm≦λ≦0.65μm, the sign of {f(λ×1.01)-f(λ)} is reversed once or more, where the sign reversal refers to the sign reversal from positive to negative and from negative to positive.

Images