How to design eyeglass lenses

Abstract

To provide a technique suitable for achieving a hyperopia reduction function by a local recess on a lens surface of a spectacle lens.SOLUTION: With spectacle lenses 1, at least one of two optical surfaces on an object side and an eyeball side is configured to include: a base surface 11 for emitting a light flux incident from the object side to the eyeball side and converging the light flux to a position A on a retina of an eyeball; and a plurality of defocus surfaces 12 for emitting the light flux incident from the object side to the eyeball side and converging the light flux to a position B separated from the object side more than the position A. A power Pb of the base surface 11 and a defocus power Ps of the defocus surface 12 are adapted to satisfy a relation of -0.25Ps<Pb<-Ps.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an eyeglass lens and a method for designing an eyeglass lens. [Background technology]

[0002] One type of spectacle lens that has a hyperopia-reducing function is one in which a local concave portion (segment surface) having a prescribed power is added to a normally prescribed lens surface (base surface).

[0003] For example, Patent Document 1 describes a spectacle lens configured with a defocus area that has the effect of converging a light beam to a position farther from the object side than position A on the retina in the direction of light propagation (i.e., further back than position A). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 067028 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a technique suitable for realizing a hyperopia reduction function by using local recesses on the lens surface of a spectacle lens. [Means for solving the problem]

[0006] A first aspect of the present invention is At least one of the two optical surfaces on the object side and the eyeball side is a base surface that outputs a light beam incident from the object side toward the eyeball side and converges it at position A on the retina of the eyeball; a plurality of defocus surfaces that emit a light beam incident from the object side toward the eyeball side and converge it at a position B that is farther from the object side than the position A; and The diopter Pb of the base surface and the defocus diopter Ps of the defocus surface satisfy the relationship of -0.25Ps < Pb < -Ps. It is an eyeglass lens.

[0007] The second aspect of the present invention is At least one of the two optical surfaces on the object side and the eyeball side is A base surface that emits a light beam incident from the object side to the eyeball side and converges it at a position A on the retina of the eyeball, A plurality of defocus surfaces that emit a light beam incident from the object side to the eyeball side and converge it at a position B farther from the object side than the position A, It is configured to have The diopter Pb of the base surface, the defocus diopter Ps of the defocus surface, and the refractive index N of the lens substrate on which the optical surface is based satisfy the relationship of Pb < -0.5(N - 1) - Ps. It is an eyeglass lens.

[0008] The third aspect of the present invention is At least one of the two optical surfaces on the object side and the eyeball side is A base surface that emits a light beam incident from the object side to the eyeball side and converges it at a position A on the retina of the eyeball, A plurality of defocus surfaces that emit a light beam incident from the object side to the eyeball side and converge it at a position B farther from the object side than the position A, It is configured to have The diopter Pb of the base surface, the defocus diopter Ps of the defocus surface, the arrangement pitch L of the defocus surface, and the planar size φ of the defocus surface satisfy the relationship of (-Ps × φ 2 ) / L 2 < Pb It is an eyeglass lens.

[0009] The fourth aspect of the present invention is For at least one of the two optical surfaces on the object side and the eyeball side, a base surface that emits the light beam incident from the object side to the eyeball side and converges it at position A on the retina of the eyeball, and a plurality of defocus surfaces that emit the light beam incident from the object side to the eyeball side and converge it at position B that is farther from the object side than the position A, and a step of designing the optical surface so as to have the above, In the step of designing the optical surface, the base surface and the defocus surface are designed such that the power Pb of the base surface and the defocus power Ps of the defocus surface satisfy the relationship of -0.25Ps < Pb < -Ps. It is a method for designing spectacle lenses.

[0010] The fifth aspect of the present invention is, For at least one of the two optical surfaces on the object side and the eyeball side, a base surface that emits the light beam incident from the object side to the eyeball side and converges it at position A on the retina of the eyeball, and a plurality of defocus surfaces that emit the light beam incident from the object side to the eyeball side and converge it at position B that is farther from the object side than the position A, and a step of designing the optical surface so as to have the above, In the step of designing the optical surface, the base surface and the defocus surface are designed such that the power Pb of the base surface, the defocus power Ps of the defocus surface, and the refractive index N of the lens substrate on which the optical surface is based satisfy the relationship of Pb < -0.5(N - 1) - Ps. It is a method for designing spectacle lenses.

[0011] The sixth aspect of the present invention is, For at least one of the two optical surfaces on the object side and the eyeball side, a base surface that emits the light beam incident from the object side to the eyeball side and converges it at position A on the retina of the eyeball, and a plurality of defocus surfaces that emit the light beam incident from the object side to the eyeball side and converge it at position B that is farther from the object side than the position A, and a step of designing the optical surface so as to have the above, In the step of designing the optical surface, the power Pb of the base surface, the defocus power Ps of the defocus surface, the arrangement pitch L of the defocus surface, and the planar size φ of the defocus surface are such that (-Ps × φ2 ) / L 2 Design the base surface and the defocus surface so as to satisfy the relationship of <Pb>. A method for designing spectacle lenses.

Effects of the Invention

[0012] According to the present invention, it is suitable for realizing a myopia reduction function by local recesses on the lens surface of spectacle lenses.

Brief Description of the Drawings

[0013] [Figure 1] It is a side sectional view showing a main part configuration example of one form of a spectacle lens having a myopia reduction function. [Figure 2] It is an explanatory view showing one form of die processing of a spectacle lens having a myopia reduction function. [Figure 3] It is an explanatory view showing one form of the external appearance of a spectacle lens having a myopia reduction function. [Figure 4] It is an explanatory view showing one form of shape measurement of a spectacle lens having a myopia reduction function. [Figure 5] It is an explanatory view showing another form of shape measurement of a spectacle lens having a myopia reduction function. [Figure 6] It is a plan view showing one form of the object side surface of a spectacle lens having a myopia reduction function. [Figure 7] It is an explanatory view schematically illustrating the optical characteristics of a spectacle lens having a myopia reduction function.

Modes for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described based on the drawings. Note that the following description is illustrative, and the present invention is not limited to the illustrated embodiments.

[0015] <Findings obtained by the inventor> Here, prior to the description of the embodiments of the present invention, the findings obtained by the inventor will be described.

[0016] 1 is a side cross-sectional view showing an example of the essential configuration of one form of eyeglass lens that has a function of reducing hyperopia. As shown in the figure, eyeglass lenses that have a function of reducing hyperopia include those in which localized recesses (segment surfaces) 12 are added to a lens surface (base surface) 11.

[0017] In a spectacle lens having such a configuration, light passing through the base surface 11 is focused at position A on the retina of the wearer's eyeball. In other words, the base surface 11 is configured to achieve a refractive power appropriately designed based on the wearer's prescription so as to focus on the retina. On the other hand, light passing through the segmented surface 12 is focused at a position farther from the object side than the retina (i.e., position B behind position A). In other words, the segmented surface 12 has a defocus power Ps that deviates from that of the base surface 11 so as to focus at a position defocused from position A, thereby achieving a refractive power different from that of the base surface 11. For this reason, in the following description, the segmented surface may also be referred to as a "defocus surface."

[0018] Thus, in principle, the base surface 11 of the spectacle lens converges the light beam to position A on the retina, while the segmented surface 12 converges the light beam to position B behind the retina. By having such optical properties, the spectacle lens has the function of reducing hyperopia, one of the refractive errors of the wearer's eyes (i.e., a hyperopia reduction function).

[0019] However, when the segment surface 12 has a concave shape, the following inconveniences may occur depending on the form of the concave shape.

[0020] The lens substrate that constitutes a spectacle lens is usually manufactured by molding using a mold. The mold used to manufacture the lens substrate is formed by cutting according to the surface shape of the lens substrate. For example, if the surface shape is such that local convex portions are added to a base surface as segment surfaces, the mold can be cut sequentially by cutting the base surface shape and then further cutting the segment surface shapes. However, if the segment surfaces are concave, such sequential cutting cannot be performed, and it is necessary to simultaneously form the base surface shape and the segment surface shape.

[0021] In this case, depending on the relationship between the base surface shape and the segment surface shape, there is a risk of problems occurring in lens manufacturing. FIG. 2 is an explanatory diagram showing one embodiment of die processing for a spectacle lens that has a hyperopia reducing function. In die machining, it is common to use different tool tips depending on the shape of the curved surface to be formed. For example, a rounded tool tip is used for a curved surface with a small negative curvature (a sharp concave curve) and a flat tool tip is used for a curved surface with a large positive or negative curvature (a gentle convex or concave curve). Therefore, for example, as shown in FIG. 2(a), if the corresponding portions of the base surface shape and the corresponding portions of the segment surface shape in a die 20 require the use of a flat tool tip 21 and a rounded tool tip 22, this may result in a decrease in productivity (efficiency) of die machining. In contrast, as shown in FIG. 2(b), if the corresponding portions of the die 20 can be machined with the same tool tip 23, this decrease in productivity can be suppressed. However, even if the decrease in productivity can be suppressed, if the tool tip shape of the tool tip 23 is not suitable for the curved surface shape to be machined, periodic machining marks may remain according to the feed pitch of the tool tip 23. Such processing marks can cause light diffraction, resulting in reflections resembling interference colors known as rainbows, which can lead to a decline in processing quality, so their occurrence should be prevented. In other words, in order to avoid inconveniences in lens manufacturing, it is preferable that the relationship between the base surface shape and the segment surface shape be such that the mold 20 can be machined using the same bit, and that the tip shape of the bit is suitable for each curved surface shape.

[0022] Furthermore, if the segment surface 12 has a concave shape, the reflected light from outside can be condensed by the concave shape, which may cause inconvenience in the appearance of the eyeglass lens depending on the type of the concave shape. FIG. 3 is an explanatory diagram showing one form of external view of a spectacle lens that has a hyperopia reducing function. A wearer of a spectacle lens with a hyperopia-reducing function may face another person while maintaining a certain distance (for example, a distance of about 2 meters, which is the social distance required). In such a case, if the concave shape constituting the segment surface is such that reflected external light is focused on the other person (for example, a gentle concave curve), as shown in Fig. 3(a), the other person (i.e., the person looking at the spectacle lens) may feel dazzled, which may be an inconvenience. In other words, the concave shape constituting the segment surface is preferably one that condenses reflected external light in front of the person facing it and turns into divergent light (for example, one with a sharp concave curve), as shown in Fig. 3(b). If reflected external light turns into divergent light, the person facing it will not feel dazzled, and inconvenience in the appearance of the eyeglass lens can be avoided. This phenomenon is unique to the concave shape, and does not pose a problem if the segment surface has a shape other than the concave shape (such as a convex shape or a flat shape), as shown in FIG. 3(c).

[0023] Furthermore, for spectacle lenses that have a hyperopia reduction function, there may be cases where it is necessary to measure the surface shape of the lens. In such cases, depending on the relationship between the base surface shape and the segment surface shape, there is a risk that inconveniences may arise in performing the shape measurement. Fig. 4 is an explanatory diagram showing one form of measuring the shape of a spectacle lens that has a hyperopia-reducing function, and Fig. 5 is an explanatory diagram showing another form of measuring the shape of a spectacle lens that has a hyperopia-reducing function. The shape of the surface of an eyeglass lens is measured using, for example, a white light interferometer. The white light interferometer measures the surface shape by converting information on interference fringes obtained from the optical path difference caused by the surface irregularities into height information. However, the interference depth of white light is narrow, about 2 μm. Therefore, for example, when the sag amount of the base surface shape is large as shown in FIG. 4(a) or when the sag amount of the segment surface shape is large as shown in FIG. 4(b), there is a risk that the depth of the white light interferometer used for shape measurement will not be sufficient to detect the surface shape. In other words, to enable shape measurement regardless of the depth of the white light interferometer, it is advantageous to have small sag amounts for both the base surface shape and the segment surface shape, as shown in FIG. 4(c). When measuring the position of a segment surface on the surface of a spectacle lens, it is possible to determine the center position of the segment surface using the boundary position between the base surface and the segment surface as a clue, for example, as shown in Figure 5(a). However, in this case, if the boundary position is sloping, there is a risk of an inconvenience in that the center position cannot be correctly determined. Therefore, it is preferable to determine the center position of the segment surface by taking into account not only the boundary position but also the minimum point of the segment surface, as shown in Figure 5(b). In other words, in order to correctly determine the center position of the segment surface, the segment surface shape must be such that the minimum point can be identified. As described above, in order to avoid inconveniences in performing shape measurement, it is preferable that the relationship between the base surface shape and the segment surface shape is such that both have a small amount of sag and that the segment surface shapes are such that the minimum points can be identified.

[0024] The present invention has been devised based on the inventor's findings described above, and provides a suitable technique for realizing a hyperopia reduction function by using localized recesses on the lens surface of a spectacle lens. Such a technique will be specifically described below in the present embodiment.

[0025] First Embodiment First, a first embodiment of the present invention will be described.

[0026] (1) Composition of eyeglass lenses As shown in Fig. 1, the eyeglass lens 1 according to this embodiment has two optical surfaces: an object-side surface 2 and an eyeball-side surface 3. The "object-side surface" is the surface that is located on the object side when eyeglasses equipped with the eyeglass lens 1 are worn by a wearer. The "eyeball-side surface" is the opposite, i.e., the surface that is located on the eyeball side when eyeglasses equipped with the eyeglass lens 1 are worn by a wearer.

[0027] The spectacle lens 1 is also configured with a lens substrate. The lens substrate is formed of a thermosetting resin material, such as thiourethane, allyl, acrylic, or epithio. Note that other resin materials that provide the desired refractive index may be selected as the resin material that constitutes the lens substrate. Alternatively, the lens substrate may be made of inorganic glass instead of a resin material.

[0028] A coating is formed on at least one of the object-side surface and the eyeball-side surface of the lens substrate. Examples of coatings include a hard coat film and an anti-reflection film (AR film), but other films may also be formed in addition to these. The hard coat film is formed using, for example, a thermoplastic resin or a UV-curable resin. The hard coat film can be formed by immersing the lens substrate in a hard coat solution, spin coating, or the like. Coating the spectacle lens 1 with such a hard coat film improves the durability of the spectacle lens 1. The anti-reflection coating is formed by vacuum deposition of an anti-reflection agent such as ZrO2, MgF2, Al2O3, etc. Coating with such an anti-reflection coating improves the visibility of images passing through the eyeglass lens 1.

[0029] The surface shape of the eyeglass lens 1 described below may be realized by the lens substrate that constitutes the eyeglass lens 1, or may be realized by a coating that covers the lens substrate.

[0030] Furthermore, the spectacle lens 1 according to this embodiment is a hyperopia-reducing lens that exhibits a hyperopia-reducing function. To this end, the spectacle lens 1 is configured such that at least one of the two optical surfaces, the object-side surface 2 and the eyeball-side surface 3, has a base surface 11 and multiple defocus surfaces 12. In this embodiment, the base surface 11 and the defocus surfaces 12 are provided on the object-side surface 2. In other words, the object-side surface 2 is configured by the base surface 11 and the multiple defocus surfaces 12. However, this is not limited to this, and the object-side surface 2 may have surfaces other than the base surface 11 and the defocus surface 12.

[0031] (base surface) The base surface 11 is a surface that constitutes a region on the lens designed based on the prescribed refractive power of the wearer. By having the base surface 11, the eyeglass lens 1 according to this embodiment is configured so that a light beam that has entered the base surface 11 from the object side is emitted from the surface 3 on the eyeball side and converges at a predetermined position (position A) on the retina via the pupil of the wearer's eyeball.

[0032] In this embodiment, the base surface 11 is a surface located on the object side and is configured as a convex surface protruding toward the object side. The convex surface configuring the base surface 11 is not particularly limited in surface shape as long as it can achieve the wearer's prescribed refractive power and does not impair the object of the present invention. That is, the surface shape of the base surface 11 may be, for example, a spherical shape, an aspherical shape, a toric shape, or a shape that is a mixture of these. In this embodiment, a case where the base surface 11 has a spherical shape is exemplified.

[0033] The prescribed refractive power achieved by the base surface 11 may be set to be weaker or stronger depending on the wearer's suitability for the glasses, preference, etc. In this case, the position where the light beam converges is not strictly speaking directly on the retina but at a position slightly shifted therefrom, but in this specification it is considered to converge on the retina.

[0034] (defocus plane) The multiple defocus surfaces 12 are surfaces that constitute areas on the lens that are designed to function as segment surfaces with different powers from the base surface 11. By having the defocus surfaces 12, the eyeglass lens 1 according to this embodiment is configured to cause a light beam that has entered the defocus surfaces 12 from the object side to exit from the surface 3 on the eyeball side and converge via the pupil of the wearer's eyeball at a position farther from the object side than position A (i.e., position B deeper on the retina than position A).

[0035] In this embodiment, the defocus surface 12 is a surface located on the object side, just like the base surface 11, but has a surface shape different from that of the base surface 11, and is configured so that the light beam is not focused at the focusing position defined by the base surface 11.

[0036] Defocus surface 12 is configured as a segmented surface with a locally concave shape. Due to this difference in surface shape, defocus surface 12 can converge the light beam at a position different from the convergence position by base surface 11 (specifically, position B deeper on the retina than position A), even if the eyeball-side surface 3 has the same surface shape in the region facing base surface 11 and the region facing defocus surface 12.

[0037] In other words, if the power of the base surface 11 is Pb (unit: D, diopter) and the defocus power of the defocus surface 12 is Ps (unit: D, diopter), the power Pb and the defocus power Ps satisfy the relationship Ps<-0.25 and Pb+Ps≧0. Here, the power Pb of the base surface 11 is the curve of the base surface 11 expressed in units of D (diopter), and satisfies the relationship Pb=1000 / {radius of curvature×(refractive index−1)}. Furthermore, the defocus power Ps of the defocus surface 12 is referred to as the "defocus power" rather than simply as a "power," and therefore represents the deviation of the curve of the defocus surface 12 from the base surface 11 in units of D (diopters). In other words, the defocus power Ps corresponds to the relative difference between the defocus surface 12 and the base surface 11. Therefore, Pb+Ps is the power of the defocus surface 12.

[0038] The surface shape of the defocus surface 12 may be, for example, spherical, but is not limited to this and may be other surface shapes. For example, the defocus surface 12 may have an aspherical shape with different curvatures between the center and periphery of the segment to add a depth-extending effect due to spherical aberration, a toroidal shape with different curvatures depending on the cross section within the segment to add astigmatism suited to ocular aberrations, an asymmetrical shape for the segment to add a depth-extending effect due to coma aberration, or a shape that combines the above shapes to combine the above aberrations.

[0039] FIG. 6 is a plan view showing one embodiment of the object-side surface of a spectacle lens that has a hyperopia reducing function. As described above, in this embodiment, the object-side surface of the spectacle lens 1 is configured to include the base surface 11 and a plurality of defocus surfaces 12. As shown in FIG. 6, the defocus surfaces 12 are formed, for example, in a circular shape in a plan view, and are arranged in an island-like manner (i.e., spaced apart and not adjacent to each other). That is, the defocus surfaces 12 are arranged discretely (i.e., not contiguous but scattered). While the case where all the defocus surfaces 12 are arranged in an island-like manner is illustrated here, this is not limiting, and the defocus surfaces 12 may be arranged so that the outer edges of adjacent areas are connected or in contact with each other. In either case, it is preferable that the arrangement of the defocus surfaces 12 be periodic. This can suppress discomfort such as blurring in a specific direction and improve the wearing comfort of the eyeglass lens 1. The number of defocus surfaces 12 to be arranged is not particularly limited, but is, for example, 20 to 500.

[0040] Furthermore, the multiple defocus surfaces 12 may be formed over the entire lens area of ​​the eyeglass lens 1, as shown in Fig. 6(a), for example, but are not limited to this. For example, as shown in Fig. 6(b), they may be formed to surround an area excluding an area near the lens center (geometric center, optical center, or centering center) of the eyeglass lens 1. Furthermore, they may be formed partially in another area (for example, only an area near the lens center). Alternatively, they may be formed in a predetermined area excluding the area near the center and the area near the outer edge of the eyeglass lens 1.

[0041] (2) Optical properties of eyeglass lenses Next, the optical characteristics of the eyeglass lens 1 having the above-described configuration will be described. FIG. 7 is an explanatory diagram that schematically illustrates the optical characteristics of a spectacle lens that has a hyperopia reducing function.

[0042] The eyeglass lens 1 having the above-described configuration is provided with the base surface 11 and the plurality of defocus surfaces 12, thereby achieving the following optical characteristics. For example, as shown in Figure 7(a), light passing through the base surface 11 is focused at position A on the retina 32 via the pupil 31 of the wearer's eyeball 30. In other words, the base surface 11 is configured to achieve a refractive power that is appropriately designed based on the wearer's prescription so as to focus the light on the retina 32, which is position A.

[0043] 7(b), for example, light passing through the defocus surface 12 is focused through the pupil 31 of the wearer's eyeball 30 at a position farther from the object side than position A (i.e., position B deeper on the retina than position A). In other words, the defocus surface 12 has a defocus power Ps that is different from that of the base surface 11 so as to focus at position B defocused from position A, thereby realizing a refractive power different from that of the base surface 11.

[0044] Note that "to focus" here means that light is concentrated to form an image, but the image does not necessarily have to be aberration-free; it may have spherical aberration or astigmatism.

[0045] Thus, in principle, the base surface 11 of the spectacle lens 1 converges the light beam at position A on the retina 32, while the portion where the defocus surface 12 is located converges the light beam at position B on the back side of position A on the retina 32. By having such optical properties, the spectacle lens 1 functions to reduce hyperopia, one of the refractive errors of the wearer's eyes (i.e., a hyperopia reduction function).

[0046] (3) Examples of segment surface shapes Next, specific aspects of the surface shape of the defocus surface 12 of the spectacle lens 1 having the optical characteristics described above will be described.

[0047] As described above, when the defocus surface 12 has a concave shape, there is a risk that inconveniences may arise in lens manufacturing depending on the mode of the concave shape.

[0048] Therefore, in the present embodiment, in order to avoid inconvenience in lens manufacturing, the surface shape of the base surface 11 (i.e., the base surface shape) and the surface shape of the defocus surface 12 (i.e., the segment surface shape) are set so that the base surface 11 and the defocus surface 12 satisfy the relationship described below.

[0049] For example, let the refractive index of the lens substrate constituting the spectacle lens 1 be N, the power of the base surface 11 be Pb [D (diopter)], and the defocus power of the defocus surface 12 be Ps [D]. In that case, the refractive power [D] of the defocus surface 12 is represented by Pb + Ps. Also, the curvature [1 / M] of the defocus surface 12 is represented by (Pb + Ps) / (N - 1). Note that the refractive index N refers to the refractive index Ne at the e-line (wavelength 546.1 nm).

[0050] Here, since the defocus surface 12 is a region for achieving a myopia reduction function, the minimum required defocus power Ps [D] is defined by the following equation (1) in order to converge the light beam to a position B behind the retina from position A.

[0051] Ps < -0.25 ···(1)

[0052] Also, even if the defocus surface 12 is concave, in order to avoid inconvenience in lens manufacturing, it is conceivable to make the absolute values of the curvatures of the base surface 11 and the defocus surface 12 equal. This is because if the respective curvatures are equal, the mold 20 can be processed with the same tool.

[0053] The base surface 11 and the defocus surface 12 have equal curvatures when they satisfy the relationship Pb = -0.5Ps. Therefore, assuming that the power Pb of the base surface 11 is about 1 < Pb < 4, if the power Pb and the defocus power Ps satisfy the relationship defined by the following equation (2), the absolute values of the curvatures of the base surface 11 and the defocus surface 12 can be made equal.

[0054] -0.25Ps < Pb < -Ps ···(2)

[0055] Incidentally, more preferably, assuming that the diopter Pb of the base surface 11 is about 1 < Pb < 3, the diopter Pb and the defocus diopter Ps may be in a relationship defined by the following formula (2)'.

[0056] -0.25Ps < Pb < -0.5Ps ···(2)'

[0057] As described above, in the present embodiment, the base surface shape and the segment surface shape are set so that the diopter Pb of the base surface 11 and the defocus diopter Ps of the defocus surface 12 satisfy at least the relationship of -0.25Ps < Pb < -Ps. Therefore, according to the spectacle lens 1 according to the present embodiment, even if the defocus surface 12 is concave, it is possible to avoid the occurrence of inconveniences in lens manufacturing while surely exhibiting the myopia reduction function.

[0058] (4) Design method and manufacturing method of spectacle lens The present invention is also applicable to a design method or a manufacturing method of the spectacle lens 1.

[0059] For example, the design method of the spectacle lens 1 includes a step of designing the optical surfaces 2 and 3 so that at least one of the two optical surfaces 2 and 3 on the object side and the eyeball side has a base surface 11 that emits the light beam incident from the object side to the eyeball side and converges it at a position A on the retina 32 of the eyeball 30, and a plurality of defocus surfaces 12 that emit the light beam incident from the object side to the eyeball side and converge it at a position B farther from the object side than the position A. In the step of designing the optical surfaces 2 and 3, the base surface 11 and the defocus surface 12 are designed so that the diopter Pb of the base surface 11 and the defocus diopter Ps of the defocus surface 12 satisfy at least the relationship of -0.25Ps < Pb < -Ps, more preferably -0.25Ps < Pb < -0.5Ps.

[0060] The manufacturing method of the spectacle lens 1 is substantially the same, and the spectacle lens 1 is manufactured through each of the above-described steps. For those other than the steps described here, they may be realized by using known techniques.

[0061] Through the design method or manufacturing method of the spectacle lens 1 as described above, the spectacle lens 1 according to the present embodiment can be obtained.

[0062] (5) Effects according to the present embodiment According to the present embodiment, one or more of the following effects can be achieved.

[0063] In the present embodiment, the spectacle lens 1 has a base surface 11 and a plurality of defocus surfaces 12. While the base surface 11 converges the light beam to position A on the retina 32, the defocus surface 12 converges the light beam to position B behind the retina 32 from position A. By having such optical characteristics, the spectacle lens 1 has a function of reducing myopia among the refractive abnormalities of the wearer's eyes (that is, a myopia reduction function).

[0064] Moreover, in the present embodiment, the spectacle lens 1 is configured such that the power Pb of the base surface 11 and the defocus power Ps of the defocus surface 12 satisfy at least the relationship of -0.25Ps < Pb < -Ps, and the base surface shape and the segment surface shape are respectively set. Therefore, even if the defocus surface 12 is concave, in the aspect as in the present embodiment, it is possible to avoid the occurrence of inconveniences in lens manufacturing.

[0065] That is, according to the present embodiment, it becomes possible to avoid inconveniences in lens manufacturing, and as a result, it is suitable for realizing the myopia reduction function by local recesses on the lens surface of the spectacle lens 1.

[0066] <Second Embodiment> Next, a second embodiment of the present invention will be described. Here, mainly the differences from the case of the first embodiment will be described.

[0067] As described above, when the defocus surface 12 has a concave shape, there is a risk that inconveniences may arise in the appearance of the spectacle lens 1 depending on the mode of the concave shape.

[0068] Therefore, in this embodiment, in order to avoid any inconvenience in the appearance of the eyeglass lens 1, the base surface shape and the segment surface shape are each set so that the base surface 11 and the defocus surface 12 satisfy the relationship described below.

[0069] For example, a wearer of a spectacle lens may face another person while maintaining a certain distance (for example, a distance of about 2 meters, which is the social distance required) (see FIG. 3). In such a case, even if the defocus surface 12 is concave, in order to prevent any inconvenience in the appearance of the spectacle lens 1, it is preferable that the reflected light of external light is condensed and turned into divergent light in front of the person facing the spectacle lens 1 (see FIG. 3(b)). If the reflected light of external light is turned into divergent light, the person facing the spectacle lens 1 will not feel dazzled, and any inconvenience in the appearance of the spectacle lens 1 can be avoided.

[0070] Here, assuming that the distance between you and the other person is about 2 m, in order to change the reflected light that may reach that other person into divergent light, it is conceivable to set the curvature of defocus surface 12 to (Pb+Ps) / (N-1)<-0.5, because with such a curvature, the reflected light of external light will be focused in front of the other person.

[0071] Therefore, by converting the relationship (Pb+Ps) / (N-1)<-0.5, the power Pb of the base surface 11 and the defocus power Ps of the defocus surface 12 satisfy the relationship defined by the following equation (3).

[0072] Pb<-0.5(N-1)-Ps (3)

[0073] As described above, in this embodiment, the base surface shape and segment surface shape are each set so that the power Pb of the base surface 11, the defocus power Ps of the defocus surface 12, and the refractive index N of the lens substrate on which the optical surfaces 2 and 3 are based satisfy the relationship Pb<-0.5(N-1)-Ps. Therefore, with the spectacle lens 1 according to this embodiment, even if the defocus surface 12 has a concave shape, it is possible to reliably achieve the hyperopia reduction function while avoiding any inconvenience in the appearance of the spectacle lens 1.

[0074] In other words, according to this embodiment, it is possible to avoid inconveniences in the appearance of the eyeglass lens 1, and as a result, it is suitable for realizing a hyperopia reduction function by using localized depressions on the lens surface of the eyeglass lens 1.

[0075] In this embodiment, as in the first embodiment, the present invention can be applied to a method for designing or manufacturing the eyeglass lens 1. For example, a method for designing a spectacle lens 1 includes a step of designing the optical surfaces 2, 3 so that at least one of the two optical surfaces 2, 3, one on the object side and one on the eyeball side, has a base surface 11 that emits a light beam incident from the object side toward the eyeball side and converges it at position A on the retina 32 of the eyeball 30, and a plurality of defocus surfaces 12 that emits a light beam incident from the object side toward the eyeball side and converges it at position B that is farther from the object side than position A. In the step of designing the optical surfaces 2, 3, the base surface 11 and the defocus surface 12 are designed so that the power Pb of the base surface 11, the defocus power Ps of the defocus surface 12, and the refractive index N of the lens substrate on which the optical surfaces 2, 3 are based satisfy the relationship Pb<-0.5(N-1)-Ps. The manufacturing method of the eyeglass lens 1 is substantially the same.

[0076] <Third embodiment> Next, a third embodiment of the present invention will be described, focusing mainly on the differences from the first or second embodiment.

[0077] As described above, when the defocus surface 12 has a concave shape, there is a risk that inconveniences may arise in measuring the shape of the eyeglass lens 1, depending on the mode of the concave shape.

[0078] Therefore, in this embodiment, in order to avoid inconveniences when measuring the shape of the eyeglass lens 1, the base surface shape and the segment surface shape are each set so that the base surface 11 and the defocus surface 12 satisfy the relationship described below.

[0079] For example, to measure the shape of the eyeglass lens 1 using a white light interferometer or the like, it is advantageous for both the base surface shape and the segment surface shape to have a small amount of sag (see FIG. 4). To achieve this, it is necessary to ensure that at least the concave defocus surface 12 is not too deep (i.e., that the range in which the tool used to process the mold can be moved is not too deep). Furthermore, when the defocus surface 12 is concave, it is preferable that the segment surface shape be such that a minimum point can be identified when measuring the position of the defocus surface 12 (see FIG. 5).

[0080] To achieve this, it is conceivable to satisfy the relationship: sag amount of base surface 11+digging amount of defocus surface 12>0 per one cycle of die machining.

[0081] Therefore, if the arrangement pitch of the defocus surfaces 12 is L [mm] and the planar size of the defocus surfaces 12 is φ [mm], the relationship between the power Pb of the base surface 11 and the defocus power Ps of the defocus surfaces 12 can be expressed by the following formula (4). Note that the arrangement pitch L is a value representing the size of the distance between the segment centers of the two closest arranged defocus surfaces 12. Furthermore, the planar size φ is a value representing the planar size of the defocus surface 12, and in the case of a planar circular shape, for example, it corresponds to the diameter size.

[0082] Pb×L 2 +Ps×φ 2 >0 (4)

[0083] When this formula (4) is transformed, the refractive power Pb and the defocus power Ps will satisfy the relationship defined by the following formula (4)'.

[0084] (-Ps × φ 2 ) / L 2 <Pb ···(4)'

[0085] As described above, in the present embodiment, the power Pb of the base surface 11, the defocus power Ps of the defocus surface 12, the arrangement pitch L of the defocus surface 12, and the planar size φ of the defocus surface 12 satisfy (-Ps × φ 2 ) / L 2 <Pb, and the shapes of the base surface and the segment surface are respectively set. Therefore, according to the spectacle lens 1 according to the present embodiment, even if the defocus surface 12 is concave, it is possible to avoid the inconvenience in measuring the shape of the spectacle lens 1 while surely achieving the myopia reduction function.

[0086] That is, according to the present embodiment, it becomes possible to avoid the inconvenience in measuring the shape of the spectacle lens 1, and as a result, it is suitable for realizing the myopia reduction function by the local concave portion on the lens surface of the spectacle lens 1.

[0087] Note that, also in the present embodiment, similar to the case of the first embodiment or the second embodiment, it is applicable to the design method or the manufacturing method of the spectacle lens 1. For example, in the design method of the spectacle lens 1, for at least one of the two optical surfaces 2 and 3 on the object side and the eyeball side, a base surface 11 that emits the light beam incident from the object side to the eyeball side and converges it at the position A on the retina 32 of the eyeball 30, and a plurality of defocus surfaces 12 that emit the light beam incident from the object side to the eyeball side and converge it at a position B that is farther from the object side than the position A are provided. Then, in the process of designing the optical surfaces 2 and 3, the power Pb of the base surface 11, the defocus power Ps of the defocus surface 12, the arrangement pitch L of the defocus surface 12, and the planar size φ of the defocus surface 12 satisfy the relationship of (-Ps×φ 2 ) / L 2 <Pb, and the base surface 11 and the defocus surface 12 are designed. The manufacturing method of the spectacle lens 1 is substantially the same.

[0088] <Modification example etc.> Although each embodiment of the present invention has been described above, the technical scope of the present invention is not limited to the above-exemplified disclosure content, and various modifications can be made without departing from the gist thereof.

[0089] For example, at least one of the two optical surfaces on the object side and the eyeball side is a base surface that emits the light beam incident from the object side to the eyeball side and converges it at the position A on the retina of the eyeball, and a plurality of defocus surfaces that emit the light beam incident from the object side to the eyeball side and converge it at a position B that is farther from the object side than the position A, and is configured to have the power Pb of the base surface and the defocus power Ps of the defocus surface satisfy the relationship of -0.25Ps<Pb<-Ps Spectacle lens. Also, for example, at least one of the two optical surfaces on the object side and the eyeball side is a base surface that emits the light beam incident from the object side to the eyeball side and converges it at the position A on the retina of the eyeball, and a plurality of defocus surfaces that emit the light beam incident from the object side to the eyeball side and converge it at a position B that is farther from the object side than the position A, is configured to have, the diopter Pb of the base surface, the defocus diopter Ps of the defocus surface, and the refractive index N of the lens substrate serving as the basis of the optical surface satisfy the relationship Pb < -0.5(N - 1) - Ps eyeglass lens. Also, for example, at least one of the two optical surfaces on the object side and the eyeball side is, a base surface that emits a light beam incident from the object side to the eyeball side and converges it at position A on the retina of the eyeball, a plurality of defocus surfaces that emit a light beam incident from the object side to the eyeball side and converge it at position B farther from the object side than the position A, is configured to have, the diopter Pb of the base surface, the defocus diopter Ps of the defocus surface, the arrangement pitch L of the defocus surfaces, and the planar size φ of the defocus surface satisfy (-Ps × φ 2 ) / L 2 < Pb eyeglass lens.

[0090] For example, each of the first to third embodiments described above is not limited to being implemented individually, and a plurality of these may be appropriately combined and implemented.

[0091] Also, for example, in each of the above-described embodiments, it can be assumed that for the plurality of defocus surfaces 12 in the eyeglass lens 1, all of them satisfy the relationships described in any of the first to third embodiments. However, the present invention is not limited to this. That is, as long as at least some of the defocus surfaces 12 satisfy the relationships described in any of the first to third embodiments, even if there are defocus surfaces that do not satisfy the relationship, they are considered to belong to the technical scope of the present invention.

[0092] Also, although specific examples (see FIGS. 6(a) and 6(b)) have been given as examples of the planar arrangement of the multiple defocus surfaces 12, the present invention is not limited to these. In other words, it is sufficient that the defocus surfaces 12 are arranged at multiple locations on the lens, and the arrangement is not limited to a specific form.

[0093] Furthermore, for example, in each of the above-described embodiments, specific values ​​have been exemplified for the power Pb of the base surface 11 and the defocus power Ps of the defocus surface 12, but the present invention is not limited to this and can be set as appropriate. That is, the base surface 11 can have a shape designed based on the prescription information of the wearer. For example, by providing the base surface 11 (e.g., the object side surface) and the other surface opposite thereto (e.g., the surface on the eyeball side), the eyeglass lens 1 can exhibit the prescribed power (power determined so as to form an image substantially on the retina under standard wearing conditions). Similarly, the shape of the defocus surface 12 can also be designed based on the prescription information of the wearer. Then, by implementing the design innovations defined in the claims, the effects of the present invention can be obtained.

[0094] Furthermore, for example, in each of the above-described embodiments, the base surface 11 and the defocus surface 12 are provided on the object side, but the present invention is not limited to this. Generally, most spectacle lenses have a convex surface on the object side, and therefore, the object side surface can be provided with the base surface 11 and the defocus surface 12. However, if the eyeball side surface has a convex surface, the base surface 11 and the defocus surface 12 may also be located on the eyeball side surface.

[0095] Furthermore, for example, in each of the above-described embodiments, an eyeglass lens 1 is illustrated as being composed of an object-side surface 2 and an eyeball-side surface 3, but this is not limited to this, and other configurations (for example, a lens having a multi-faceted bonded configuration that includes a functional film such as a polarizing film inside the lens) are also included within the technical scope of the present invention.

[0096] In the spectacle lens 1, the diopter provided on the base surface 11 and the defocus surface 12, part or all of the defocus diopter can be recorded on any surface of the lens by engraving or the like. Further, at least part of other information regarding the lens (for example, wearer information described later) can also be recorded on the spectacle lens 1 by the same or different means.

[0097] In addition, the spectacle lens 1 may be managed in a state linked (linked) to wearer information regarding the wearer of the lens. That is, the spectacle lens 1 and the wearer information may be treated as a lens product or may be the subject of a transaction. In that case, for example, the wearer information may be recorded on a lens case used in the lens transaction process, or recorded on a recording medium possessed by a trading business including an optical store, or provided or transmitted by an electronic communication line in a state where the lens can be collated. The wearer information may include the prescription information of the wearer (for example, spherical diopter, cylindrical diopter, astigmatic axis, etc.), or may include fitting parameters (interpupillary distance of the wearer, forward tilt angle at the time of fitting determined by the frame used, frame corneal distance, etc.).

[0098] The technical scope of the present invention includes the following spectacle lenses. For example, at least one of the two optical surfaces on the object side and the eyeball side is a base surface that emits a light beam incident from the object side to the eyeball side and converges it at position A, a plurality of defocus surfaces that emit a light beam incident from the object side to the eyeball side and converge it at a position B farther from the object side than the position A, and is configured to have where the diopter Pb of the base surface and the defocus diopter Ps of the defocus surface satisfy the relationship of -0.25Ps < Pb < -Ps spectacle lens. Further, for example, at least one of the two optical surfaces on the object side and the eyeball side is A base surface that emits a light beam incident from the object side toward the eye side and converges it at position A, a plurality of defocus surfaces that emit a light beam incident from the object side toward the eye side and converge it at position B that is farther from the object side than the position A, and is configured to have, the diopter Pb of the base surface, the defocus diopter Ps of the defocus surface, and the refractive index N of the lens substrate that is the basis of the optical surface satisfy the relationship Pb < -0.5(N - 1) - Ps eyeglass lens. Also, for example, at least one of the two optical surfaces on the object side and the eye side is a base surface that emits a light beam incident from the object side toward the eye side and converges it at position A, a plurality of defocus surfaces that emit a light beam incident from the object side toward the eye side and converge it at position B that is farther from the object side than the position A, and is configured to have, the diopter Pb of the base surface, the defocus diopter Ps of the defocus surface, the arrangement pitch L of the defocus surface, and the planar size φ of the defocus surface satisfy the relationship (-Ps × φ 2 ) / L 2 < Pb eyeglass lens.

Explanation of Reference Numerals

[0099] 1... eyeglass lens, 2... surface on the object side, 3... surface on the eye side, 11... base surface, 12... defocus surface (segment surface), 30... eye, 31... pupil, 32... retina

Claims

[Claim 1] a step of designing the optical surface so that at least one of the two optical surfaces, one on the object side and one on the eyeball side, has a base surface that emits a light beam incident from the object side toward the eyeball side and converges it at position A on the retina of the eyeball, and a plurality of defocus surfaces that emit the light beam incident from the object side toward the eyeball side and converges it at position B that is farther from the object side than position A, In the step of designing the optical surface, the base surface and the defocus surface are designed so that a power Pb of the base surface, which is a convex surface, and a defocus power Ps corresponding to a relative difference between the base surface and the defocus surface, which is a concave surface, satisfy the relationship of -0.25Ps<Pb<-Ps and also satisfy the relationship of Pb=-0.5Ps. How to design eyeglass lenses.

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