Spectacle lens and method for designing spectacle lens

Abstract

A spectacle lens (1) in which at least one of both optical surfaces on the object side and on the eyeball side is disposed so as to have: a base surface (11) at a position A at which a light beam incident from the object side is emitted toward the eyeball side and converged on the retina of the eyeball; and a plurality of defocus surfaces (12) that emit a light beam incident from the object side toward the eyeball side and converge the light beam at a position B farther from the object side than the position A. The eyeglass lens (1) is configured such that the degree Pb of the base surface (11) and the degree Ps of defocus of the defocus surfaces (12) satisfy-0.25 Pslt; pblt; -Ps.

Description

Technical Field

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

[0002] As a form of an ophthalmic lens that exhibits a function of reducing hyperopia, there is an ophthalmic lens in which a locally concave portion (segmented surface) having a power is added to the surface (base surface) of a lens with a normal prescription.

[0003] For example, Patent Document 1 relates to an ophthalmic lens in which a defocus area is configured to converge a light beam to a position that is farther from the object side than the position A on the retina in the traveling direction of light (i.e., a position that is farther back than the position A). [Prior Art Documents] [Patent Documents]

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

[0005] An object of the present invention is to provide a technique suitable for achieving a function of reducing hyperopia by using a locally concave portion on the lens surface of an ophthalmic lens. Solutions to the Problems

[0006] A first aspect of the present invention is as follows: An ophthalmic lens, wherein at least one of the two optical surfaces on the object side and the eyeball side is configured to have: a base surface that causes a light beam incident from the object side to exit toward the eyeball side and converge at a position A on the retina of the eyeball; and a plurality of defocus surfaces that cause a light beam incident from the object side to exit toward the eyeball side and converge at a position B that is farther from the object side than the position A, a relationship between the power Pb of the base surface and the defocus power Ps of the defocus surface satisfies -0.25Ps < Pb < -Ps.

[0007] A second aspect of the present invention is as follows: An ophthalmic lens, wherein at least one of the two optical surfaces on the object side and the eyeball side is configured to have: a base surface that causes a light beam incident from the object side to exit toward the eyeball side and converge at a position A on the retina of the eyeball; and a plurality of defocus surfaces that cause a light beam incident from the object side to exit toward the eyeball side and converge at a position B that is farther from the object side than the position A, 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 Pb < -0.5(N - 1) - Ps.

[0008] The third aspect of the present invention is: An ophthalmic lens, wherein at least one of the two optical surfaces on the object side and the eye side is configured to have: a base surface that causes a light beam incident from the object side to exit toward the eye side and converge at position A on the retina of the eye; and a plurality of defocus surfaces that cause a light beam incident from the object side to exit toward the eye side and converge at position B that is farther from the object side than position A, 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 dimension φ of the defocus surfaces satisfy (-Ps × φ 2 ) / L 2 < Pb.

[0009] The fourth aspect of the present invention is: A method for designing an ophthalmic lens, the design method comprising: a step of designing an optical surface such that at least one of the two optical surfaces on the object side and the eye side has: a base surface that causes a light beam incident from the object side to exit toward the eye side and converge at position A on the retina of the eye; and a plurality of defocus surfaces that cause a light beam incident from the object side to exit toward the eye side and converge 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 such that the diopter Pb of the base surface and the defocus diopter Ps of the defocus surface satisfy the relationship -0.25Ps < Pb < -Ps.

[0010] The fifth aspect of the present invention is: A method for designing an ophthalmic lens, the design method comprising: a step of designing an optical surface such that at least one of the two optical surfaces on the object side and the eye side has: a base surface that causes a light beam incident from the object side to exit toward the eye side and converge at position A on the retina of the eye; and a plurality of defocus surfaces that cause a light beam incident from the object side to exit toward the eye side and converge 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 such that 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 Pb < -0.5(N - 1) - Ps.

[0011] The sixth aspect of the present invention is: A design method for spectacle lenses, the design method comprising: A process of designing an optical surface such that at least one of the two optical surfaces on the object side and the eyeball side has: a base surface that causes a light beam incident from the object side to exit toward the eyeball side and converge at position A on the retina of the eyeball; and a plurality of defocus surfaces that cause a light beam incident from the object side to exit toward the eyeball side and converge at position B that is farther from the object side than position A, In the process of designing the optical surface, the base surface and the defocus surfaces are designed such that the power Pb of the base surface, the defocus power Ps of the defocus surfaces, the arrangement pitch L of the defocus surfaces, and the planar size φ of the defocus surfaces satisfy (-Ps×φ 2 ) / L 2 < the relationship of < Pb. Advantages of the Invention

[0012] According to the present invention, the local recesses on the lens surface of the spectacle lens are suitable for realizing the function of reducing hyperopia. Brief Description of the Drawings

[0013] Figure 1 is a side sectional view showing an example of the main part structure of a spectacle lens having a hyperopia-reducing function. Figure 2 is an explanatory view showing an example of the mold processing of a spectacle lens having a hyperopia-reducing function. Figure 3 is an explanatory view showing an example of the appearance vision of a spectacle lens exerting a hyperopia-reducing function. Figure 4 is an explanatory view showing an example of the shape measurement of a spectacle lens exerting a hyperopia-reducing function. Figure 5 is an explanatory view showing another form of the shape measurement of a spectacle lens exerting a hyperopia-reducing function. Figure 6 is a plan view showing an example of the surface on the object side of a spectacle lens exerting a hyperopia-reducing function. Figure 7 is an explanatory view schematically showing the optical characteristics of a spectacle lens exerting a hyperopia-reducing function. Detailed Description of the Embodiments

[0014] Hereinafter, embodiments of the present invention will be described based on the drawings. In addition, the following description is exemplary, and the present invention is not limited to the embodiments shown by way of example.

[0015] <Findings Obtained by the Inventor> Here, before describing the embodiments of the present invention, the findings obtained by the inventor will be described.

[0016] Figure 1 The side cross-sectional view is a diagram showing an example of the main part structure of a spectacle lens having a hyperopia reduction function. As shown in the figure, as a spectacle lens having a hyperopia reduction function, there is a form in which a local concave portion (segmented surface) 12 is added to a lens surface (base surface) 11.

[0017] In the spectacle lens having such a configuration, light passing through the base surface 11 converges at position A on the retina of the wearer's eyeball. That is, the base surface 11 is designed to achieve a refractive power appropriately designed based on the wearer's prescription to focus on the retina. On the other hand, light passing through the segmented plane 12 is focused at a position farther from the object side than on the retina (that is, position B further back than position A). That is, the segmented surface 12 has a defocus degree Ps deviated from the base surface 11 to focus at a position defocused from position A, thereby achieving a refractive power different from that of the base surface 11. Therefore, in the following description, the segmented plane may also be referred to as a "defocusing plane".

[0018] Thus, in the spectacle lens, in principle, the base surface 11 converges the light beam at position A on the retina, and the segmented surface 12 converges the light beam at position B behind the retina. By having such optical characteristics, the spectacle lens has a function of alleviating hyperopia in the refractive error of the wearer's eye (i.e., a hyperopia alleviating function).

[0019] Incidentally, when the segmented surface 12 has a concave shape, the following disadvantages may occur depending on the form of this concave shape.

[0020] The lens substrate constituting the eyeglass lens is generally manufactured by molding using a mold. And, the mold for manufacturing the lens substrate is formed by cutting processing according to the surface shape of the lens substrate. For example, for mold processing, if the surface has a surface shape in which a local convex portion is added as a segmented surface to the base surface, cutting can be performed sequentially by drilling the base surface shape and then adding the segmented surface shape. However, if the segmented surface has a concave shape, it is impossible to perform cutting sequentially in such a sequence, and it is necessary to form the base surface shape and the segmented surface shape at the same time.

[0021] In this case, there is a possibility that problems may occur in manufacturing the lens depending on the relationship between the substrate surface shape and the segment surface shape. Figure 2 This is an explanatory diagram showing one aspect of mold processing of a spectacle lens having a hyperopia alleviating function. For example, in mold processing, for example, in a mold, for a curved surface shape whose curvature is negative and small (a concave curve changes sharply), a round-head cutting tool is usually used; and for a curved surface shape whose curvature is positive or negative and large, as long as the curvature is large (a convex curve or a concave curve is relatively gentle), different cutting tools with different tip shapes are usually used according to the curved surface shape to be formed, such as a flat-head cutting tool. Therefore, for example, Figure 2 As shown in (a), if the corresponding part of the base surface shape and the corresponding part of the segmented surface shape in the mold 20 are in a relationship that requires the use of the flat-end cutting tool 21 and the round-end cutting tool 22, there is a risk of reducing the productivity (efficiency) of mold processing. On the other hand, if Figure 2 As shown in (b), if the corresponding parts of the mold 20 can be processed using the same cutting tool 23, the reduction in productivity can be suppressed. However, even if the reduction in productivity can be suppressed, if the tip shape of the cutting tool 23 is not suitable for the curved surface shape to be processed, there is a risk that processing marks formed periodically according to the feed pitch of the cutting tool 23 may remain. Such processing marks cause light diffraction and reflection of interference colors called rainbows, resulting in a decrease in processing quality, so their occurrence should be prevented. That is, regarding the relationship between the base surface shape and the segmented surface shape, in order to avoid inconvenience in lens manufacturing, the same cutting tool can be used to process the mold 20, and preferably, the tip shape of the cutting tool is suitable for each curved surface shape.

[0022] In addition, when the segmented surface 12 is in a concave shape, reflected light of external light may be condensed by the concave shape, and therefore, depending on the shape of such a concave shape, there is a risk that a problem may occur in the visual appearance of the eyeglass lens. Figure 3 This is an explanatory diagram showing one form of the visual appearance of a spectacle lens that exhibits a hyperopia reduction function. A person wearing spectacle lenses having a hyperopia reduction function can face another person while maintaining a certain distance (for example, a distance of about 2 meters to be maintained as a social distance). In this case, for example, Figure 3 As shown in (a), if the concave shape constituting the segmented surface is in a form such that the reflected light of the external light is focused toward another person on the opposite side (for example, a gentle concave curve), the other person on the opposite side (i.e., the person who is looking at the glasses lens visually) may experience discomfort such as glare. That is, Figure 3As shown in (b), regarding the concave shape constituting the segmented surface, it is preferred that the reflected light of the external light is focused at a position further in front of the other person opposite and converted into divergent light (for example, a sharply changing concave curve). This is because if the reflected light of the external light is converted into divergent light, the other person opposite will not feel glare, and the visual discomfort caused by the glasses lens can be avoided. In addition, this phenomenon is unique to concave shapes, e.g. Figure 3 As shown in (c), no problem will occur if the segment surface has a shape other than a concave shape (a convex shape, a flat shape, etc.).

[0023] In addition, it may be necessary to measure the surface shape of eyeglass lenses with a hyperopia reduction function. In this case, problems may arise when performing shape measurement depending on the relationship between the base surface shape and the segmented surface shape. Figure 4 This is an explanatory diagram showing one method of measuring the shape of a spectacle lens that exerts a hyperopia reduction function. Figure 5 This is an explanatory diagram showing another form of shape measurement of a spectacle lens that exerts a hyperopia reduction function. The surface shape of eyeglass lenses is measured, for example, using a white interferometer. The white interferometer measures the surface shape by converting interference fringe information obtained from the optical path difference caused by the surface concavity and convexity into height information. However, the interference depth of white light is as narrow as about 2 μm. Therefore, for example, when Figure 4 When the amount of sag of the base surface shape shown in (a) is large, or when Figure 4 When the droop amount of the segmented surface shape shown in (b) is large, there is a risk that the surface shape cannot be detected at the depth of the white interferometer used for shape measurement. That is, in order to be able to measure the shape regardless of the depth of the white interferometer, as shown in FIG. Figure 4 As shown in (c), it is advantageous that both the base surface shape and the segment surface shape have a small amount of sag. When measuring the position of a segment plane on the surface of an eyeglass lens, e.g. Figure 5 As shown in (a), the center position of the segmented surface can be identified by using the boundary position between the base surface and the segmented surface as a clue. However, in this case, if the boundary position is inaccurate, there is a risk of inconvenience such as failure to correctly determine the center position. Therefore, Figure 5 As shown in (b), in addition to the boundary position, it is preferred to identify the center position of the segmented surface by considering the local minimum of the segmented surface. That is, in order to correctly identify the center position of the segmented surface, the segmented surface needs to have a shape that allows the local minimum to be identified. As described above, in order to avoid inconvenience in shape measurement, it is preferable that the relationship between the base surface shape and the segment surface shape is such that the sagging amount is small and the minimum point can be identified.

[0024] The present invention is designed based on the above findings of the inventors, and provides a technology suitable for realizing a hyperopia reduction function through a local concave portion on the lens surface of a spectacle lens. Below, this technology will be specifically explained in this embodiment.

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

[0026] (1) Structure of eyeglass lenses like Figure 1 As shown, the spectacle lens 1 according to this embodiment has a surface 2 on the object side and a surface 3 on the eyeball side as two optical surfaces. The "surface on the object side" is a surface located on the object side when the wearer wears the glasses equipped with the spectacle lens 1. The "surface on the eyeball side" is the opposite, that is, a surface located on the eyeball side when the wearer wears the glasses equipped with the spectacle lens 1.

[0027] In addition, the eyeglass lens 1 is configured to include a lens substrate. The lens substrate is formed of a thermosetting resin material such as thiourethane, allyl, acrylic acid, and episulfide. It should be noted that as the resin material constituting the lens substrate, other resin materials that can obtain the required refractive power can also be selected. In addition, the lens substrate made of inorganic glass can also be used instead of the 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 the coating include hard coatings and anti-reflection films (AR films), but other films may also be formed. The hard coating film is formed using, for example, a thermoplastic resin or a UV curable resin. The hard coating film can be formed by immersing the lens substrate in a hard coating liquid or by spin coating, etc. The coating of the hard coating film can improve the durability of the eyeglass lens 1. The anti-reflection film is formed by vacuum evaporation of an anti-reflection agent such as ZrO2, MgF2, Al2O3, etc. The visibility of the image transmitted through the eyeglass lens 1 can be improved by coating with such an anti-reflection film.

[0029] It should be noted that the surface shape of the spectacle lens 1 described below may be realized by a lens base material constituting the spectacle lens 1 or by a coating covering the lens base material.

[0030] In addition, the spectacle lens 1 according to the present embodiment is a hyperopia reduction lens that exerts a hyperopia reduction function. Therefore, the spectacle lens 1 is configured so that at least one of the two optical surfaces of the surface 2 on the object side and the surface 3 on the eyeball side has a base surface 11 and a plurality of defocused surfaces 12. In the present embodiment, the base surface 11 and the defocused surfaces 12 are provided on the surface 2 on the object side. That is, the surface 2 on the object side is constituted by the base surface 11 and the plurality of defocused surfaces 12. However, this is not limited to this, and the surface 2 on the object side may have surfaces other than the base surface 11 and the defocused surfaces 12.

[0031] (Substrate surface) The base surface 11 is a surface constituting a region portion on the lens designed according to the prescription power of the wearer. By having the base surface 11, the spectacle lens 1 according to the present embodiment is configured so that a light beam incident on the base surface 11 from the object side is emitted from the surface 3 on the eyeball side and converges to a predetermined position (position A) on the retina through the pupil of the wearer's eyeball.

[0032] In the present embodiment, the base surface 11 is a surface located on the object side and is composed of a convex surface protruding toward the object side. The convex surface constituting the base surface 11 is not particularly limited in its surface shape as long as it can achieve the prescribed refractive power of the wearer and within the scope that does not impair the purpose of the present invention. That is, the surface shape of the base surface 11 can be, for example, a spherical shape, an aspherical shape, a toric shape, or a mixed shape thereof. In the present embodiment, the case where the base surface 11 is a spherical shape is exemplified.

[0033] It should be noted that the prescription refractive power realized by the base surface 11 can be set to reduce or increase the refractive power according to the wearer's adaptation or preference to the glasses. In this case, the position where the light beam converges is not strictly speaking directly above the retina, but at a slightly deviated position, but is regarded as converging toward the retina in this specification.

[0034] (Defocused surface) The plurality of defocusing surfaces 12 are surfaces constituting a region portion on the lens, wherein each defocusing surface 12 is designed to function as a segmented surface having a different power from the base surface 11. By having the defocusing surfaces 12, the spectacle lens 1 according to the present embodiment is configured so that a light beam incident on the defocusing surface 12 from the object side is emitted from the surface 3 on the eyeball side and converges to a position farther from the object side than the position A (i.e., a position B further back from the retina than the position A) through the pupil of the wearer's eyeball.

[0035] In the present embodiment, the defocusing plane 12 is a plane located on the object side like the base surface 11 , but has a surface shape different from that of the base surface 11 and is configured not to focus the light beam to the focusing position of the base surface 11 .

[0036] The defocusing surface 12 is configured as a segmented surface with a local concave shape. Due to this difference in surface shape, even if the surface 3 on the eyeball side has the same surface shape in the area relative to the base surface 11 and the area relative to the defocusing surface 12, the defocusing surface 12 can converge the light beam to a position different from the focusing position of the base surface 11 (specifically, position B that is closer to the retina than position A).

[0037] That is, if the degree of the base surface 11 is set to Pb (unit: D, diopter) and the defocus degree of the defocus surface 12 is set to Ps (unit: D, diopter), the degree Pb and the defocus degree Ps satisfy the relationship of Ps<-0.25 and Pb+Ps≥0. Here, the power Pb of the base surface 11 is a curve of the base surface 11 expressed in units of D (diopter), and satisfies the relationship of Pb=1000 / {radius of curvature×(refractive index-1)}. In addition, since the defocus degree Ps of the defocus surface 12 is not just a "degree" but is called a "defocus degree", the deviation of the curve of the defocus surface 12 relative to the base surface 11 is expressed in units of D (diopter). That is, the defocus degree Ps is equivalent to the relative difference between the defocus surface 12 and the base surface 11. Therefore, Pb+Ps is the degree of the defocus surface 12.

[0038] In addition, the surface shape of the defocused surface 12 may be, for example, a spherical shape, but is not limited thereto, and other surface shapes may be used. For example, in order to increase the depth extension effect due to spherical aberration, it may be designed to have an aspherical shape with different curvatures in the center and the peripheral part within the segment; in order to accommodate the eyeball aberration and the additional astigmatism, it may be designed to have a spiral shape with different curvatures through the cross section within the segment; in order to add the depth extension effect of the coma aberration, it may be designed to have an asymmetric shape; or in order to compound the above aberrations, it may also be designed to have a shape compounding the above shapes.

[0039] Figure 6 This is a plan view showing one embodiment of the object-side surface of a spectacle lens having a hyperopia alleviating function. As described above, in the present embodiment, the object-side surface of the spectacle lens 1 includes the base surface 11 and the plurality of defocusing surfaces 12 . Among them, Figure 6As shown, a plurality of defocused surfaces 12 are formed into a circle in a plan view, for example, and are respectively arranged in an island shape (i.e., in a state of being separated from each other without being adjacent to each other). That is, each defocused surface 12 is respectively arranged discretely (i.e., in a state of being discontinuous and scattered with each other). However, although the case where all the defocused surfaces 12 are arranged in an island shape is illustrated here, it is not limited to this, and each defocused surface 12 may also be arranged in a manner including portions where the outer edges of adjacent areas are connected to or adjacent to each other. In any case, the arrangement of each defocused surface 12 is preferably periodic. Thereby, it is possible to suppress unpleasant sensations such as blurring in a certain direction and improve the wearing feel of the eyeglass lens 1. It should be noted that the number of defocused surfaces 12 to be arranged is not particularly limited, but, for example, it may be more than 20 and less than 500.

[0040] In addition, for example, Figure 6 As shown in (a), each of the plurality of defocusing surfaces 12 may be formed on the entire lens of the eyeglass lens 1, but is not limited thereto. Figure 6 As shown in (b), in addition to the vicinity of the lens center (geometric center, optical center, or centering center) of the spectacle lens 1, it can also be formed in a manner surrounding the area. In addition, it can also be partially formed in other parts (for example, only the vicinity of the lens center). Alternatively, it can also be formed in a predetermined area other than the vicinity of the center and the vicinity of the outer edge of the spectacle lens 1.

[0041] (2) Optical properties of eyeglass lenses Next, the optical characteristics of the spectacle lens 1 having the above-mentioned structure will be described. Figure 7 It is an explanatory diagram schematically showing the optical characteristics of a spectacle lens that exerts a hyperopia reduction function.

[0042] The spectacle lens 1 having the above-described structure can achieve the following optical characteristics by including the base surface 11 and the plurality of defocusing surfaces 12 . For example, Figure 7 As shown in (a), the light passing through the base surface 11 is focused on the position A on the retina 32 via the pupil 31 of the wearer's eyeball 30. That is, the base surface 11 is focused on the retina 32 as the position A, thereby realizing the refractive power appropriately designed according to the wearer's prescription.

[0043] On the other hand, for example, Figure 7 As shown in (b), the light passing through the defocusing surface 12 is focused on a position farther from the object side than the position A (i.e., a position B further back from the retina than the position A) via the pupil 31 of the eyeball 30 of the wearer. That is, the defocusing surface 12 has a defocus power Ps deviating from the base surface 11, so as to focus on the position B defocused from the position A, thereby realizing a refractive power different from that of the base surface 11.

[0044] It should be noted that the “focusing” mentioned here refers to the concentration of light into an image, but it does not necessarily require an aberration-free image, and may also have spherical aberration or astigmatism.

[0045] Thus, in the spectacle lens 1, on the one hand, the base surface 11 converges the light beam at the position A on the retina 32 in principle, and on the other hand, the portion provided with the defocusing surface 12 converges the light beam at the position B which is further back than the position A on the retina 32. By having such optical characteristics, the spectacle lens 1 performs the function of alleviating hyperopia in the refractive error of the wearer's eye (i.e., hyperopia alleviating function).

[0046] (3) Specific examples of segmented surface shapes Next, specific aspects of the surface shape of the defocusing surface 12 of the spectacle lens 1 having the optical characteristics as described above will be described.

[0047] As described above, when the defocusing surface 12 is in a concave shape, there is a risk that problems may occur in lens manufacturing due to such a concave shape.

[0048] Therefore, in this 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 defocusing surface 12 (i.e., the segmented surface shape) are set respectively so that the surface shape of the base surface 11 and the defocusing surface 12 satisfy the following relationship.

[0049] For example, the refractive index of the lens substrate constituting the eyeglass lens 1 is N, the power of the base surface 11 is Pb[D (diopter)], and the defocus power of the defocus surface 12 is Ps[D]. In this case, the refractive power [D] of the defocus surface 12 is expressed as Pb+Ps. In addition, the curvature [1 / M] of the defocus surface 12 is expressed as (Pb+Ps) / (N-1). In addition, the refractive index N refers to the refractive index Ne at the e-line (wavelength 546.1nm).

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

[0051] Ps<-0.25...(1)

[0052] Furthermore, even if the defocusing surface 12 has a concave shape, in order to avoid any inconvenience in manufacturing the lens, it is conceivable to make the absolute values ​​of the curvatures of the base surface 11 and the defocusing surface 12 the same. This is because if the respective curvatures are the same, the mold 20 can be processed using the same cutting tool.

[0053] When the base surface 11 and the defocus surface 12 satisfy the relation Pb = -0.5Ps, the base surface 11 and the defocus surface 12 have the same curvature. Therefore, assuming that the power Pb of the base surface 11 is approximately 1 < Pb < 4, if the power Pb and the defocus power Ps have the relation defined by the following formula (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] Furthermore, more preferably, assuming that the power Pb of the base surface 11 is approximately 1 < Pb < 3, the power Pb and the defocus power Ps are also set to have the relation defined by the following formula (2)'.

[0056] -0.25Ps < Pb < -0.5Ps...(2)'

[0057] As described above, in the present embodiment, both the base surface shape and the segmented surface shape are set such that the power Pb of the base surface 11 and the defocus power Ps of the defocus surface 12 satisfy at least the relation -0.25Ps < Pb < -Ps. Therefore, according to the spectacle lens 1 of the present embodiment, even if the defocus surface 12 has a concave shape, the hyperopia alleviating function can be reliably exerted, and any inconvenience in lens manufacturing can be avoided.

[0058] (4) Design method and manufacturing method of spectacle lens The present invention is also applicable to a method for designing or manufacturing 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 such 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 makes the light beam incident from the object side exit toward the eyeball side and converge at a position A on the retina 32 of the eyeball 30; and a plurality of defocus surfaces 12 that make the light beam incident from the object side exit toward the eyeball side and converge at a position B that is farther from the object side than the position A. And, in the step of designing the optical surfaces 2 and 3, the base surface 11 and the defocus surface 12 are designed such that the power Pb of the base surface 11 and the defocus power Ps of the defocus surface 12 satisfy the relation -0.25Ps < Pb < -Ps, and more preferably satisfy the relation -0.25Ps < Pb < -0.5Ps.

[0060] The manufacturing method of the spectacle lens 1 is also substantially the same, and after the above-mentioned steps, the spectacle lens 1 is manufactured. It should be noted that, except for the steps described here, it can be realized as long as the known technology is used.

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

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

[0063] In this embodiment, the spectacle lens 1 has a base surface 11 and a plurality of defocusing surfaces 12, wherein the base surface 11 focuses the light beam at a position A on the retina 32, and the defocusing surfaces 12 focus the light beam at a position B which is further back than the position A on the retina 32. By having such optical characteristics, the spectacle lens 1 can exert a function of reducing hyperopia in the refractive error of the wearer's eyes (i.e., a hyperopia reducing function).

[0064] In addition, in the present embodiment, in the spectacle lens 1, the base surface shape and the segmented surface shape are both set so that the power Pb of the base surface 11 and the defocus power Ps of the defocus surface 12 at least satisfy the relationship of -0.25Ps<Pb<-Ps. Therefore, even if the defocus surface 12 has a concave shape, according to the aspects of the present embodiment, the inconvenience in lens manufacturing can be avoided.

[0065] That is, according to the present embodiment, inconvenience in lens manufacturing can be avoided, and therefore, the local depression on the lens surface of the spectacle lens 1 is suitable for achieving the hyperopia alleviating function.

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

[0067] As described above, when the defocusing surface 12 has a concave shape, there is a risk that a problem may occur in the visual appearance of the spectacle lens 1 due to such a concave shape.

[0068] Therefore, in the present embodiment, in order to avoid any discomfort in the visual appearance of the spectacle lens 1 , the base surface shape and the segment surface shape are respectively set so that the base surface 11 and the defocusing surface 12 satisfy the relationship described below.

[0069] For example, a wearer of a spectacle lens can face another person while maintaining a certain distance (for example, a distance of about 2 meters to be maintained as social distance) (see Figure 3 In this case, even if the defocusing surface 12 has a concave shape, in order to avoid any visual discomfort caused by the spectacle lens 1, it is preferred that the reflected light of the external light is focused at a position further forward than the other person opposite and converted into divergent light (see Figure 3 (b)). This is because, if the reflected light of the external light is changed into the divergent light, another person facing the spectacle lens 1 will not feel the glare, and any discomfort in the visual appearance of the spectacle lens 1 can be avoided.

[0070] Here, assuming that the distance between you and the person you are facing is about 2m, in order to convert the reflected light that can reach the other person into divergent light, it can be considered that the curvature of the defocusing surface 12 = (Pb + Ps) / (N-1) < -0.5. This is because, with such a curvature, the reflected light of the external light will be focused at a position further in front of the other person facing you.

[0071] Therefore, through the conversion 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 formula (3).

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

[0073] As described above, in the present embodiment, the base surface shape and the segmented surface shape are 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 of Pb<-0.5(N-1)-Ps. Therefore, according to the spectacle lens 1 of the present embodiment, even if the defocus surface 12 has a concave shape, the hyperopia reduction function can be reliably exerted while preventing any discomfort from being caused visually in the appearance of the spectacle lens 1.

[0074] That is, according to this embodiment, the discomfort in the visual appearance of the spectacle lens 1 can be avoided, and as a result, the visual appearance problems of the spectacle lens 1 can be avoided, and as a result, the hyperopia reduction function can preferably be achieved through the local recessed portion on the lens surface of the spectacle lens 1.

[0075] Furthermore, as in the case of the first embodiment, the present embodiment can also be applied to a method of designing or manufacturing the spectacle lens 1 . For example, the design method of the eyeglass 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 causes a light beam incident from the object side to be emitted toward the eyeball side and converged at a position A on the retina 32 of the eyeball 30; and a plurality of defocusing surfaces 12 that cause a light beam incident from the object side to be emitted toward the eyeball side and converged at a position B farther from the object side than the position A. Furthermore, in the step of designing the optical surfaces 2 and 3, the base surface 11 and the defocusing surfaces 12 are designed so that the power Pb of the base surface 11, the defocusing power Ps of the defocusing surfaces 12, and the refractive index N of the lens substrate where the optical surfaces 2 and 3 are located satisfy the relationship of Pb<-0.5(N-1)-Ps. The method for manufacturing the spectacle lens 1 is also substantially the same.

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

[0077] As described above, when the defocusing surface 12 has a concave shape, depending on the form of this concave shape, there is a risk that inconvenience may occur when measuring the shape of the spectacle lens 1 .

[0078] Therefore, in this embodiment, in order to avoid the inconvenience in measuring the shape of the spectacle lens 1 , the base surface shape and the segment surface shape are set respectively so that the base surface 11 and the defocusing surface 12 satisfy the following relationship.

[0079] For example, in order to measure the shape of the spectacle lens 1 using a white interferometer or the like, it is advantageous that both the base surface shape and the segmented surface shape have a small amount of sag (see Figure 4 ). For this reason, at least the concave defocusing surface 12 needs to be formed so that the concave shape does not become too deep (that is, the range in which the cutting tool for processing the mold moves does not become too deep). In addition, when the defocusing surface 12 has a concave shape, when measuring the position of the defocusing surface 12, it is preferred that the shape of the defocusing surface 12 is a segmented surface shape capable of identifying a minimum point (see Figure 5 ).

[0080] For this purpose, it is conceivable that the following relationship is satisfied: the sagging amount of the base surface 11 per cycle of mold processing + the recessed amount of the defocused surface 12 >0.

[0081] Therefore, if the arrangement pitch of the defocused surface 12 is L [mm], and the plane size of the defocused surface 12 is φ [mm], the relationship between the degree Pb of the base surface 11 and the defocus degree Ps of the defocused surface 12 is The defocused surface 12 can be expressed by the following formula (4). In addition, the arrangement pitch L is a value indicating the size of the interval between the line segment centers of two defocused surfaces 12 arranged closest to each other. In addition, the plane size φ is a value indicating the plane size of the defocused surface 12, and, for example, corresponds to the diameter size in the case of a plane circle.

[0082] Pb×L 2 +Ps×φ 2 >0...(4)

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

[0084] (-Ps×φ 2 ) / L 2 <Pb...(4)'

[0085] As described above, in the present embodiment, the base surface shape and the segmented surface shape are respectively set such that the power Pb of the base surface 11, the defocus power Ps of the defocus surface 12, the arrangement pitch L of the defocus surfaces 12, and the planar size φ of the defocus surfaces 12 satisfy (-Ps × φ 2 ) / L 2 < the relationship of < Pb. Therefore, with the spectacle lens 1 according to the present embodiment, even if the defocus surface 12 has a concave shape, it is possible to avoid inconvenience when measuring the shape of the spectacle lens 1, and at the same time, the hyperopia alleviation function can be reliably achieved.

[0086] That is, according to the present embodiment, it is possible to avoid inconvenience when measuring the shape of the spectacle lens 1. As a result, it is preferable to achieve the hyperopia alleviation function by local depressions on the lens surface of the spectacle lens 1.

[0087] In addition, as in the case of the first embodiment or the second embodiment, the present embodiment can also be applied to a method for designing or manufacturing the spectacle lens 1. For example, in the design method of the spectacle lens 1, the design method of the spectacle lens 1 includes: a step of designing the optical surfaces 2 and 3 such that at least one of the two optical surfaces 2 and 3 on the object side and the eye side has: a base surface 11 that causes a light beam incident from the object side to exit toward the eye side and converge at a position A on the retina 32 of the eye 30; and a plurality of defocus surfaces 12 that cause a light beam incident from the object side to exit toward the eye side and converge at a position B that is farther from the object side than the position A. In the process of designing the optical surfaces 2 and 3, the base surface 11 and the defocus surfaces 12 are designed such that the power Pb of the base surface 11, the defocus power Ps of the defocus surfaces 12, the arrangement pitch L of the defocus surfaces 12, and the planar size φ of the defocus surfaces satisfy (-Ps × φ 2 ) / L 2 < the relationship of < Pb. The manufacturing method of the spectacle lens 1 is also substantially the same.

[0088] <Modifications, etc.> As described above, the embodiments of the present invention have been described, but the technical scope of the present invention is not limited to the above-exemplarily disclosed content, and various modifications can be made without departing from the gist thereof.

[0089] For example, a spectacle lens, wherein, at least one of the two optical surfaces on the object side and the eye side is configured to have: a base surface that causes a light beam incident from the object side to exit toward the eye side and converge at a position A on the retina of the eye; and a plurality of defocus surfaces that cause a light beam incident from the object side to exit toward the eye side and converge at a position B that is farther from the object side than the position A, The diopter Pb of the base surface and the defocus diopter Ps of the defocus surface satisfy the relationship of -0.25Ps < Pb < -Ps. In addition, for example, an ophthalmic lens, wherein, At least one of the two optical surfaces on the object side and the eye side is configured to have: A base surface that causes a light beam incident from the object side to exit toward the eye side and converge at position A on the retina of the eye; and A plurality of defocus surfaces that cause a light beam incident from the object side to exit toward the eye side and converge at position B that is farther from the object side than position A, 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. In addition, for example, an ophthalmic lens, wherein, At least one of the two optical surfaces on the object side and the eye side is configured to have: A base surface that causes a light beam incident from the object side to exit toward the eye side and converge at position A on the retina of the eye; and A plurality of defocus surfaces that cause a light beam incident from the object side to exit toward the eye side and converge at position B that is farther from the object side than position A, 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 surfaces satisfy (-Ps × φ 2 ) / L 2 < Pb.

[0090] For example, each of the above first to third embodiments is not limited to being implemented alone, and multiple embodiments can be implemented in an appropriate combination.

[0091] In addition, for example, in each of the above embodiments, for the plurality of defocus surfaces 12 in the ophthalmic lens 1, although it can be assumed that all of them satisfy the relationships described in any one of the first to third embodiments, the present invention is not limited thereto. That is, as long as at least some of the defocus surfaces 12 satisfy the relationships described in any one of the first to third embodiments, even if there are defocus surfaces that do not satisfy these relationships, they fall within the technical scope of the present invention.

[0092] In addition, specific examples are given for the planar configuration of the plurality of defocus surfaces 12 (see Figure 6 (a), 6(b)), but the present invention is not limited thereto. That is, the defocus surfaces 12 only need to be arranged at a plurality of positions on the lens, and the arrangement manner is not limited to a specific manner.

[0093] Furthermore, for example, in the above-described embodiments, specific values ​​are given 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 thereto and can be appropriately set. That is, the base surface 11 can have a shape designed according to the prescription information of the wearer. For example, by having the base surface 11 (e.g., the surface on the object side) and another surface opposite thereto (e.g., the surface on the eyeball side), the eyeglass lens 1 can exert the prescription power (determined as the power that can be basically imaged on the retina in the standard wearing state). In addition, the shape of the defocusing surface 12 can also be a shape designed according to the prescription information of the wearer. On this basis, by carrying out the design innovation specified in the claims, the effect of the present invention can be obtained.

[0094] In addition, for example, in each of the above-mentioned embodiments, the case where the base surface 11 and the defocused surface 12 are provided on the surface on the object side is described as an example, but the present invention is not limited to this. Generally, since many eyeglass lenses have a convex surface on the object side, the base surface 11 and the defocusing surface 12 may be provided on the surface on the object side. However, in the case where the surface on the eyeball side has a convex surface, the base surface 11 and the defocusing surface 12 may also be provided on the surface on the eyeball side.

[0095] In addition, for example, in the above-mentioned embodiments, an eyeglass lens 1 composed of a surface 2 on the object side and a surface 3 on the eyeball side is illustrated, but it is not limited to this. Other aspects (for example, an eyeglass lens having a multi-faceted joint structure including a functional film such as a polarizing film inside the lens) are also included in the technical scope of the present invention.

[0096] In the spectacle lens 1, the power of the base surface 11 and the defocusing surface 12, and part or all of the defocus power, can be recorded on any surface of the lens by means of engraving or the like. In addition, at least a part of other information related to 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 is sometimes managed in a state of being associated (linked) with the wearer information about the wearer of the lens. That is, the spectacle lens 1 and the wearer information are sometimes handled together as a lens product or as an object of transaction. In this case, for example, the wearer information can be provided or communicated through an electronic communication line while being recorded on a lens bag used in the transaction process of the lenses, or recorded on a recording medium held by a dealer including an eyewear store, or in a state in which the lenses can be queried. The wearer information may include the prescription information of the wearer (e.g., spherical power, cylindrical power, axis of astigmatism, etc.), or may include wearing parameters (interpupillary distance of the wearer, forward tilt angle during wearing determined by the used frame, distance between the frame and the cornea, etc.).

[0098] The following spectacle lenses are included within the technical scope of the present invention. For example, a spectacle lens, wherein at least one of the two optical surfaces on the object side and the eyeball side is configured to have: a base surface that makes the light beam incident from the object side exit toward the eyeball side and converge at position A on the retina of the eyeball; and a plurality of defocus surfaces that make the light beam incident from the object side exit toward the eyeball side and converge at position B that is farther from the object side than the said position A, the power Pb of the base surface and the defocus power Ps of the defocus surfaces satisfy the relationship of -0.25Ps < Pb < -Ps. In addition, for example, a spectacle lens, wherein at least one of the two optical surfaces on the object side and the eyeball side is configured to have: a base surface that makes the light beam incident from the object side exit toward the eyeball side and converge at position A on the retina of the eyeball; and a plurality of defocus surfaces that make the light beam incident from the object side exit toward the eyeball side and converge at position B that is farther from the object side than the said position A, the power Pb of the base surface, the defocus power Ps of the defocus surfaces, 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. In addition, for example, a spectacle lens, wherein at least one of the two optical surfaces on the object side and the eyeball side is configured to have: a base surface that makes the light beam incident from the object side exit toward the eyeball side and converge at position A on the retina of the eyeball; and a plurality of defocus surfaces that make the light beam incident from the object side exit toward the eyeball side and converge at position B that is farther from the object side than the said position A, the power Pb of the base surface, the defocus power Ps of the defocus surfaces, the arrangement pitch L of the defocus surfaces, and the planar size φ of the defocus surfaces satisfy the relationship of (-Ps × φ 2 ) / L 2 < Pb.

Symbol Explanation

[0099] 1...spectacles lens, 2...surface on the object side, 3...surface on the eyeball side, 11...base surface, 12...defocusing surface (segmented surface), 30...eyeball, 31...pupil, 32...retina.

Claims

1. An eyeglass lens, wherein, at least one of the two optical surfaces on the object side and the eyeball side is configured to have: a base surface that emits the 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 converge it at position B that is farther from the object side than the said position A, the power Pb of the base surface and the defocus power Ps of the defocus surfaces satisfy the relationship of -0.25Ps < Pb < -Ps.

2. An eyeglass lens, wherein, at least one of the two optical surfaces on the object side and the eyeball side is configured to have: a base surface that emits the 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 converge it at position B that is farther from the object side than the said position A, the power Pb of the base surface, the defocus power Ps of the defocus surfaces, 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.

3. An eyeglass lens, wherein, at least one of the two optical surfaces on the object side and the eyeball side is configured to have: a base surface that emits the 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 converge it at position B that is farther from the object side than the said position A, The degree Pb of the base surface, the defocus degree Ps of the defocus surface, the arrangement pitch L of the defocus surfaces, and the planar dimension φ of the defocus surface satisfy (-Ps × φ 2 ) / L 2 < the relationship of Pb.

4. A design method for an eyeglass lens, the design method comprising: a step of designing an optical surface such that at least one of the two optical surfaces on the object side and the eyeball side has: a base surface that emits the 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 converge it at position B that is farther from the object side than the said position A, in the step of designing the optical surface, the base surface and the defocus surfaces are designed such that the power Pb of the base surface and the defocus power Ps of the defocus surfaces satisfy the relationship of -0.25Ps < Pb < -Ps.

5. A design method for an eyeglass lens, the design method comprising: a step of designing an optical surface such that at least one of the two optical surfaces on the object side and the eyeball side has: a base surface that emits the 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 converge it at position B that is farther from the object side than the said position A, in the step of designing the optical surface, the base surface and the defocus surfaces are designed such that the power Pb of the base surface, the defocus power Ps of the defocus surfaces, 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.

6. A design method for an eyeglass lens, the design method comprising: The process of designing the optical surface is to make at least one of the two optical surfaces on the object side and the eyeball side have: a base surface that causes a light beam incident from the object side to be emitted toward the eyeball side and to be focused at a position A on the retina of the eyeball; and a plurality of defocusing surfaces that cause a light beam incident from the object side to be emitted toward the eyeball side and to be focused at a position B farther from the object side than the position A. In the process 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, the arrangement pitch L of the defocus surface, and the planar size φ of the defocus surface satisfy (-Ps × φ 2 ) / L 2 < the relationship of Pb.

Images