Eyeglass lenses and methods for designing eyeglass lenses

Abstract

To provide a spectacle lens capable of suppressing false light focusing on a front side of a retina in the spectacle lens having a farsightedness reduction function.SOLUTION: A spectacle lens has a base area of emitting a light flux incident from a surface on a side of an object from a surface on a side of an eyeball to focus the light flux at a predetermined position A on a retina through the eyeball and a plurality of defocus areas having a character of focusing the light flux at a position B distant from the object side rather than the position A. A value (d1 / d2) obtained by dividing the diameter d1 of a circumscribed circle of a triangle obtained by connecting centers of three nearest neighbor defocus areas by the diameter d2 of the defocus area is more than 2 and less than 3.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to spectacle lenses and a method for designing spectacle lenses.

Background Art

[0002] As one form of spectacle lenses having a myopia reduction function, there is a type in which a small recessed portion (segment surface) with a diopter is added to a normally prescribed lens surface (base surface).

[0003] For example, Patent Document 1 discloses a spectacle lens in which a defocus region is configured to have an action of converging a light beam at a position farther from the object side than the position on the retina in the traveling direction of light (that is, on the back side of position A).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] One embodiment of the present invention aims to provide a spectacle lens capable of suppressing false convergence on the front side of the retina in a spectacle lens having a myopia reduction function.

Means for Solving the Problems

[0006] The first aspect of the present invention is a base region that emits a light beam incident from the object-side surface from the eyeball-side surface and converges it at a predetermined position A on the retina through the eyeball, and a plurality of defocus regions having a property of converging a light beam at a position B farther from the object side than the position A, The spectacle lens is such that the value obtained by dividing the diameter d1 of the circumscribed circle of the triangle connecting the centers of the three nearest defocus regions by the diameter d2 of the defocus region (d1 / d2) is greater than 2 and less than 3.

[0007] A second aspect of the present invention is: The spectacle lens according to the first embodiment, wherein the plurality of defocus regions are arranged spaced apart from each other and not adjacent to one another.

[0008] A third aspect of the present invention is: The spectacle lens according to the first or second embodiment, having a functional region in which the plurality of defocus regions are arranged such that the diameter d1 falls within a range of ±20%.

[0009] A fourth aspect of the present invention is: The spectacle lens according to the third embodiment, wherein the area ratio of the defocused area in the functional area is 30% or more.

[0010] A fifth aspect of the present invention is: The spectacle lens according to any one of the first to fourth embodiments, wherein the surface shape of the plurality of defocus regions is spherical.

[0011] A sixth aspect of the present invention is: The spectacle lens is a farsightedness-reducing lens, and is a spectacle lens according to any one of the first to fifth embodiments described above.

[0012] A seventh aspect of the present invention is: A process of designing a base region that causes a light beam incident from the object side to exit from the eyeball side and converge to a predetermined position A on the retina via the eyeball, The process includes designing a plurality of defocus regions that have the property of converging the light beam to a position B that is further away from the object than the aforementioned position A, In the process of designing the aforementioned multiple defocus regions, the method for designing eyeglass lenses involves designing the multiple defocus regions such that the value obtained by dividing the diameter d1 of the circumscribed circle of the triangle connecting the centers of the three nearest defocus regions by the diameter d2 of the defocus region (d1 / d2) is greater than 2 and less than 3. [Effects of the Invention]

[0013] According to one embodiment of the present invention, it is possible to provide spectacle lenses that have a hyperopia reduction function and can suppress false focusing on the front side of the retina. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic diagram illustrating the occurrence of false light focusing in an eyeglass lens related to a reference example. [Figure 2] Figure 2 is a graph showing an example of the relationship between contrast (vertical axis) calculated by wave optics and the amount of defocus (horizontal axis) relative to position A in a spectacle lens for reference. [Figure 3] Figure 3 is a plan view of the object-side surface of the eyeglass lens 100 according to the first embodiment of the present invention. [Figure 4] Figure 4 is an example of an enlarged plan view of the defocus region 20 of the spectacle lens 100 according to the first embodiment of the present invention. [Figure 5] Figure 5(a) shows the arrangement of the defocus area 20 in sample 1 according to an embodiment of the present invention, Figure 5(b) shows the arrangement of the defocus area 20 in sample 2 according to an embodiment of the present invention, Figure 5(c) shows the arrangement of the defocus area 20 in sample 3 according to an embodiment of the present invention, and Figure 5(d) shows the arrangement of the defocus area 20 in sample 4 according to an embodiment of the present invention. [Figure 6]FIG. 6(a) is a graph showing the relationship between the contrast and the defocus amount obtained by wave-optical calculation of Sample 1 according to an embodiment of the present invention, FIG. 6(b) is a graph showing the relationship between the contrast and the defocus amount obtained by wave-optical calculation of Sample 2 according to an embodiment of the present invention, FIG. 6(c) is a graph showing the relationship between the contrast and the defocus amount obtained by wave-optical calculation of Sample 3 according to an embodiment of the present invention, and FIG. 6(d) is a graph showing the relationship between the contrast and the defocus amount obtained by wave-optical calculation of Sample 4 according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0015] <Findings Obtained by the Inventor> First, the findings obtained by the inventor will be described. FIG. 1 is a schematic diagram for explaining the occurrence of false focusing in a spectacle lens according to a reference example. In FIG. 1, a partial cross-section of the spectacle lens is schematically represented. Note that the base surface 110 shown in FIG. 1 generally has a curve according to the design, but here it is shown as a plane for simplicity. The horizontal axis in FIG. 1 sets a predetermined position (position A) on the retina as 0, with the back side of the retina represented as + and the front side of the retina represented as -. The vertical axis in FIG. 1 sets position A as 0, with the upper side represented as + and the lower side represented as -. In this specification, unless otherwise specified, in the following figures as well, the back side of the retina will be represented as + and the front side of the retina will be represented as -.

[0016] ​​​​Here, as shown in FIG. 1, a light ray passing through the upper end of the segment surface 111 (Segment1 upper light ray) and a light ray passing through the lower end of the segment surface 112 (Segment2 lower light ray) intersect at a position C on the front side of the retina. Therefore, between the retina and the position C, spots formed by light beams passing through the segment surface 111 and spots formed by light beams passing through the segment surface 112 overlap, and false convergence occurs on the front side of the retina.

[0018] FIG. 2 is a graph showing an example of the relationship between the contrast (vertical axis) obtained by wave optics calculation and the defocus amount (horizontal axis) based on the position A in the spectacle lens according to the reference example. The horizontal axis of FIG. 2 shows the distance from the retina, converted into defocus diopters. As shown in FIG. 2, when false convergence occurs, in addition to the main peak I1 on the retina due to the base surface and the peak I2 on the back side of the retina due to the segment surface, it was found that there is also a contrast peak I3 on the front side of the retina. Such a peak I3 due to false convergence may prevent the effect of a myopia-reducing lens, which controls the stimulation received by the retina by providing a spot on the back side of the retina and reduces myopia. That is, when the peak I3 due to false convergence is prominent, it may not be possible to sufficiently obtain the effect of myopia reduction.

[0019] In the contrast calculation, an index called VSOTF was used. VSOTF is a scalar quantity taking into account the contrast sensitivity characteristics thought to be caused by the retinal structure or the nervous system. VSOTF is the sum of the real parts of the OTF weighted considering the sensitivity characteristics for each spatial frequency of the eye. The specific mathematical formula is as follows.

Equation

[0020] OTF is a measure used to evaluate lens performance. It is a complex numerical index that represents how faithfully the contrast of an object being viewed can be reproduced on the image plane, expressed as a spatial frequency characteristic. A large absolute value of OTF means that the contrast perceived by the wearer when viewing an object through the lens is high, and a small OTF deviation means that the positional displacement of the image is small. A large VSOTF value, which is the weighted sum of OTFs, means that there is less blurring and smudging of the image and a high degree of energy concentration.

[0021] Regarding VSOTF, it is described in the following document: "Thibos LN, Hong X, Bradley A, Applegate RA. Accuracy and precision of objective refraction from wavefront aberrations. J Vis. 2004 Apr 23;4(4):329-51.", and therefore, an explanation will be omitted here.

[0022] The inventors diligently investigated the problems described above. As a result, they found that by appropriately controlling the shape, size, and arrangement of the segment surfaces, it is possible to make the false focus peaks function as part of the main peak on the retina (embedded by the main peak) without making them apparent. This effectively suppresses the formation of peaks due to false focus, thereby effectively reducing hyperopia. Furthermore, suppressing false focus can also improve the wearing comfort of eyeglass lenses.

[0023] [Details of the Embodiments of the Invention] Next, one embodiment of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these examples and is intended to include all modifications within the meaning and scope equivalent to the claims, as shown in the claims.

[0024] The spectacle lenses described herein have an object-facing surface and an eye-facing surface. The "object-facing surface" is the surface that faces the object when the spectacle lenses are worn by the wearer, and the "eye-facing surface" is the opposite surface, that is, the surface that faces the eye when the spectacle lenses are worn by the wearer. This relationship also applies to the lens substrate that forms the basis of the spectacle lenses. In other words, the lens substrate also has an object-facing surface and an eye-facing surface.

[0025] <First Embodiment of the Invention> (1) Eyeglass lenses Figure 3 is a plan view of the object-side surface of the eyeglass lens 100 of this embodiment. The eyeglass lens 100 of this embodiment is a hyperopia-reducing lens that provides a hyperopia-reducing function and comprises a base region 10 and a plurality of defocus regions 20. In this embodiment, the base region 10 is the region on which the above-mentioned base surface is formed. The base region 10 is a refractive region designed to reflect the wearer's prescribed refractive power, and is designed to cause a light beam incident from the object-side surface to exit from the eye-side surface and converge to a predetermined position (position A) on the retina via the wearer's eyeball. In this embodiment, the defocus region 20 is the region on which the above-mentioned segment surface is formed. The defocus region 20 is configured to cause a light beam incident from the object-side surface to exit from the eye-side surface and converge the light beam via the wearer's eyeball to a position further away from the object side than position A (i.e., position B, further back on the retina than position A).

[0026] The base region 10 is the part of the lens that can achieve the wearer's prescribed refractive power, and its surface shape is not particularly limited. The base region 10 may be spherical, aspherical, toric, or a combination of these. In this embodiment, the case in which the base region 10 is spherical is given as an example.

[0027] The defocus region 20 is a region in which at least a portion of the light is not focused to the focusing position of the base region 10. The multiple defocus regions 20 in this embodiment only need to be formed on at least one of the object-side surface or the eye-side surface of the spectacle lens 100. In this embodiment, an example is given in which the multiple defocus regions 20 are provided only on the object-side surface of the spectacle lens 100.

[0028] The surface shape of the defocus region 20 is preferably spherical. If the defocus region 20 is aspherical, a bright area called a "flame surface" may be generated around the outer edge of the spot, potentially increasing false focusing. In contrast, by making the surface shape of the defocus region 20 spherical, the increase in false focusing can be suppressed. In this embodiment, "the surface shape of the defocus region 20 is spherical" includes not only cases where the defocus region 20 is perfectly spherical, but also cases where it is spherical over a range of 90% or more of its diameter. In this embodiment, the case where the defocus region 20 is a spherical concave surface is given as an example.

[0029] The number of defocus areas 20 provided by the eyeglass lens 100 is not particularly limited, but for example, it is between 20 and 500.

[0030] In this embodiment, the multiple defocus regions 20 are arranged, for example, in an island-like manner (i.e., spaced apart from each other without being adjacent). It is preferable that the arrangement of the multiple defocus regions 20 has periodicity. This suppresses discomfort such as blurring in a specific direction and improves the wearing comfort of the eyeglass lens 100.

[0031] As shown in Figure 3, a defocus region 20 may or may not be formed in the central part of the spectacle lens 100. In this specification, the central part of the spectacle lens 100 refers to the lens center (geometric center, optical center, or centering center) and its vicinity. In this embodiment, an example is given in which the line of sight of the wearer of the spectacle lens 100 when looking straight ahead passes through the lens center.

[0032] Figure 4 is an example of an enlarged plan view of the defocus region 20. Here, as shown in Figure 4, consider the circumcircle of a triangle connecting the centers of the three nearest defocus regions 20, and let its diameter be d1. Also, let the diameter of the defocus region 20 be d2. If the diameters of the three nearest defocus regions 20 are different, the average of the three may be used as the diameter d2. If the shape of the defocus region 20 is not a perfect circle in plan view due to manufacturing errors, etc., the diameter of the approximated circle may be used as d2. In this embodiment, "the three nearest defocus regions 20" means the three defocus regions 20 selected to minimize the diameter d1, including the defocus region 20 of interest.

[0033] We will now explain how the aforementioned diameters d1 and d2 have a significant influence on the occurrence of false focusing. Below, using equation (1), we will express the air-equivalent distance x (mm) from the retina as a defocus degree X (unit: diopter, Dpt) to make the relationship with the optical effect clearer. X is defined, like the air-equivalent distance x, as being positive on the far side of the retina and negative on the near side of the retina. x = (1000 / eye prescription - 1000 / (eye prescription + X)) ... (1)

[0034] To simplify the explanation, we will describe an example where false focusing occurs due to two defocus regions 20. As shown in Figure 1, false focusing occurs between the defocus point q where the upper ray of Segment 1 and the lower ray of Segment 2 intersect and the retina. To derive q, we need to find the difference in y coordinates Δy and the difference in slopes Δa of the upper ray of Segment 1 and the lower ray of Segment 2 on the retina (x=0). The difference in y coordinates Δy is expressed by the following equation (2). Δy = diameter d² × segment power ÷ eye power ... (2)

[0035] Furthermore, the slope of the upper ray of Segment 1 is given by segment radius × (segment power + eye power) / 1000, and the slope of the lower ray of Segment 2 is given by -segment interval × eye power / 1000 + segment radius × (segment power + eye power) / 1000. Therefore, the difference Δa is given by the following equation (3). Note that the segment interval in equation (3) actually corresponds to the diameter d1. Segment interval × Eye power / 1000 - Diameter d2 × (Segment power + Eye power) / 1000 ... (3)

[0036] q can be derived by the following equation (4). Δy + q × Δa = 0 ···(4)

[0037] Using equation (1), we convert q to the defocusing frequency Q, substitute it into equation (4), and solve for Q to obtain the following equation (5). Q = -Segment frequency × diameter d² ÷ (Segment interval - diameter d²) ... (5)

[0038] In equation (5), if we let the segment spacing be diameter d1 and d1 / d2 = K, we obtain the following equation (6). Q / Segment Frequency = -1 / (K-1) ... (6)

[0039] Therefore, as shown in equation (6), only K affects the relationship between normal focusing and false focusing.

[0040] The inventors have found that by setting the value K (=d1 / d2), obtained by dividing diameter d1 by diameter d2, to greater than 2 and less than 3, false focusing on the front side of the retina can be suppressed. When the value K is 2 or less, the contrast peak due to false focusing becomes prominent, and the effect of reducing hyperopia may not be sufficiently obtained. In contrast, by setting the value K to greater than 2, the peak due to false focusing can be made to function as part of the main peak on the retina (so that it is buried in the main peak), thereby substantially suppressing the formation of peaks due to false focusing and efficiently obtaining the effect of reducing hyperopia. In addition, by suppressing false focusing, the number of peaks outside the retina is reduced, which also improves the wearing comfort of the spectacle lens 100. On the other hand, when the value K is 3 or greater, the area ratio of the defocused area 20 to the base area 10 becomes small, and the effect of reducing hyperopia may not be sufficiently obtained. In contrast, by setting the value K to less than 3, the area ratio of the defocused area 20 can be ensured to be greater than a predetermined value, so the effect of reducing hyperopia can be efficiently obtained.

[0041] The value K is more preferably greater than 2.2 and less than 2.5. By setting the value K to greater than 2.2, the peak position due to false focusing is closer to the main peak on the retina, thus improving the contrast of the main peak. Also, by setting the value K to less than 2.5, a larger area ratio of the defocus region 20 can be secured, thus further reducing the effect of hyperopia.

[0042] As shown in Figure 3, the eyeglass lens 100 of this embodiment preferably has a functional region 30. The functional region 30 is a part in which multiple defocus regions 20 are arranged such that the diameter d1 falls within a range of ±20% (preferably ±10%). In other words, multiple defocus regions 20 are arranged such that the diameter d1 when focusing on one defocus region 20 within the functional region 30 falls within a range of ±20% of the diameter d1 when focusing on another defocus region 20 within the functional region 30. The fact that multiple defocus regions 20 are arranged so that the diameter d1 falls within a range of ±20% indicates that the arrangement of the multiple defocus regions 20 has a certain degree of periodicity. Therefore, by having a functional region 30, discomfort such as blurring in a specific direction can be suppressed and the wearing comfort of the eyeglass lens 100 can be improved.

[0043] On the other hand, the functional region 30 is a region where false focusing is likely to occur because the arrangement of the multiple defocus regions 20 has a certain degree of periodicity. However, in this embodiment, as described above, by controlling the value K, it is possible to suppress false focusing while improving the wearing comfort of the spectacle lens 100.

[0044] While defocus areas 20 may be located in areas other than the functional area 30, from the viewpoint of improving the wearing comfort of the eyeglass lens 100, it is preferable that, for example, 80% or more (more preferably 90% or more) of the defocus areas 20 of all the defocus areas 20 of the eyeglass lens 100 are located in the functional area 30.

[0045] The functional area 30 preferably occupies 50% or more of the area within a circle with a diameter of 20 mm from the center of the spectacle lens 100. The circle with a diameter of 20 mm from the center of the lens is assumed to be within the range of everyday visual behavior. This makes it possible to efficiently obtain the effect of reducing farsightedness while improving the wearing comfort of the spectacle lens 100.

[0046] In the functional area 30, the area ratio of the defocus area 20 is preferably, for example, 30% or more and 60% or less (more preferably 40% or more and 60% or less). If the area ratio of the defocus area 20 is less than 30%, the effect of reducing hyperopia may not be sufficiently obtained. On the other hand, by setting the area ratio of the defocus area 20 to 30% or more, the effect of reducing hyperopia can be sufficiently obtained. Conversely, if the area ratio of the defocus area 20 exceeds 60%, it may adversely affect the wearing comfort and appearance of the spectacle lens 100. On the other hand, by setting the area ratio of the defocus area 20 to 60% or less, the wearing comfort and appearance of the spectacle lens 100 can be maintained.

[0047] It should be noted that the value K is not necessarily greater than 2 and less than 3 for all defocused areas 20. From the viewpoint of efficiently suppressing false focusing, it is preferable that the value K is greater than 2 and less than 3 for 80% or more (more preferably 90% or more) of the defocused areas 20 located within the functional area 30 (or all the defocused areas 20 provided by the spectacle lens 100).

[0048] Various commonly used lens substrates can be used as the lens substrate constituting the eyeglass lens 100. The lens substrate may be, for example, a plastic lens substrate or a glass lens substrate. The glass lens substrate may be, for example, a lens substrate made of inorganic glass. As a lens substrate, a plastic lens substrate is preferred from the viewpoint of being lightweight and less prone to breakage. Examples of plastic lens substrates include styrene resins such as (meth)acrylic resin, polycarbonate resin, allyl resin, allyl carbonate resin such as diethylene glycol bisallyl carbonate resin (CR-39), vinyl resin, polyester resin, polyether resin, urethane resin obtained by the reaction of an isocyanate compound with a hydroxyl compound such as diethylene glycol, thiourethane resin obtained by the reaction of an isocyanate compound with a polythiol compound, and cured products (generally called transparent resins) obtained by curing a curable composition containing a (thio)epoxy compound having one or more disulfide bonds in the molecule. The curable composition may also be called a polymerizable composition. As the lens substrate, an undyed one (colorless lens) or a dyed one (dyed lens) may be used. The thickness and diameter of the lens substrate are not particularly limited, but for example, the thickness (center thickness) may be about 1 to 30 mm, and the diameter may be about 50 to 100 mm. The refractive index of the lens substrate may be, for example, about 1.60 to 1.75. However, the refractive index of the lens substrate is not limited to this range, and may be within this range or outside of it. In this specification, refractive index refers to the refractive index for light with a wavelength of 500 nm.

[0049] (2) Design and manufacturing methods for eyeglass lenses The present invention is also applicable to a method for designing or manufacturing eyeglass lenses 100. The method for designing (manufacturing) eyeglass lenses 100 in this embodiment includes the steps of: designing a base region 10 that causes a light beam incident from the object-side surface to exit from the eye-side surface and converge to a predetermined position (position A) on the retina via the eyeball; and designing a plurality of defocus regions 20 that have the property of converging the light beam to a position further away from the object side than position A (i.e., position B, further back on the retina than position A). In the step of designing the plurality of defocus regions 20, the plurality of defocus regions 20 are designed such that the value K (=d1 / d2), obtained by dividing the diameter d1 of the circumscribed circle of the triangle connecting the centers of the three nearest defocus regions 20 by the diameter d2 of the defocus region 20, is greater than 2 and less than 3. Details of the base region 10 and defocus regions 20 designed in each step are omitted because they overlap with the description of eyeglass lenses in (1) above.

[0050] <Other embodiments of the present invention> Although embodiments of the present invention have been specifically described above, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0051] For example, in the above embodiment, a case was described in which multiple defocus areas 20 are arranged at a distance from each other without being adjacent to one another. However, it is not necessarily the case that all defocus areas 20 are arranged at a distance from each other without being adjacent to one another. However, if multiple defocus areas 20 are arranged adjacent to each other, the wearing comfort of the eyeglass lens 100 may be reduced, such as blurring in the direction in which the defocus areas 20 are connected. Therefore, from the viewpoint of improving the wearing comfort of the eyeglass lens 100, for example, it is preferable that 90% or more of the defocus areas 20 of all the defocus areas 20 provided by the eyeglass lens 100 are arranged at a distance from each other without being adjacent to one another, and it is more preferable that all defocus areas 20 located within the functional area 30 are arranged at a distance from each other without being adjacent to one another. [Examples]

[0052] Next, embodiments of the present invention will be described. These embodiments are examples of the present invention, and the present invention is not limited to these embodiments.

[0053] Sample 1 of the spectacle lens 100 was designed under the following conditions: The base region 10 and the defocus region 20 were spherical in shape. Figure 5(a) shows the arrangement of the defocus region 20 of Sample 1. Segment frequency (relative frequency of defocused region 20 relative to base region 10): -3.5D Area ratio of defocused region 20: 46% The diameter d1 of the circumscribed circle of the triangle connecting the centers of the three nearest defocus regions 20 is 1.67 mm. Diameter d2 of defocused area 20: 1.0 mm Value K: 1.67

[0054] Furthermore, sample 2 of the spectacle lens 100 was designed in the same way as sample 1, except that the arrangement of the defocus region 20 was changed, the diameter d1 was set to 1.91 mm, and the value K was set to 1.91. Figure 5(b) shows the arrangement of the defocus region 20 in sample 2.

[0055] Furthermore, sample 3 of the spectacle lens 100 was designed in the same way as sample 1, except that the arrangement of the defocus area 20 was changed, the diameter d1 was set to 2.31 mm, and the value K was set to 2.31. Figure 5(c) shows the arrangement of the defocus area 20 in sample 3.

[0056] Furthermore, sample 4 of the spectacle lens 100 was designed in the same way as sample 1, except that the arrangement of the defocus area 20 was changed, the diameter d1 was set to 2.31 mm, and the value K was set to 2.31. Figure 5(d) shows the arrangement of the defocus area 20 of sample 4.

[0057] For samples 1 through 4, the relationship between contrast and defocus was calculated using wave optics. The results for sample 1 are shown in Figure 6(a), the results for sample 2 in Figure 6(b), the results for sample 3 in Figure 6(c), and the results for sample 4 in Figure 6(d).

[0058] As shown in Figure 6(a), in sample 1, where the value K was 2 or less (1.67), a peak I3 due to false focusing appeared in front of the retina (-2.7Dpt). Similarly, as shown in Figure 6(b), in sample 2, where the value K was 2 or less (1.91), a peak I3 due to false focusing also appeared in front of the retina (-2.0Dpt). In contrast, as shown in Figures 6(c) and 6(d), in samples 3 and 4, where the value K was greater than 2 (2.31), no peak I3 due to false focusing appeared in front of the retina. Therefore, it was confirmed that by setting the value K to greater than 2, the peak I3 due to false focusing is buried by the main peak I1 on the retina, effectively suppressing false focusing. [Explanation of Symbols]

[0059] 10 Base area 20 Defocused areas 30 Functional Areas 100 eyeglass lenses 110 Base surface Segment surfaces 111 and 112

Claims

1. A base region that causes a light beam incident from the object-side surface to exit from the eye-side surface and converges it to a predetermined position A on the retina via the eyeball, It comprises a plurality of defocus regions having the property of converging the light beam to a position B that is further away from the object than the aforementioned position A, The diameter d of the circumscribed circle of the triangle connecting the centers of the three nearest defocus regions. １ The diameter d of the defocus region ２ The value obtained by dividing by (d １ / d ２ ) is greater than 2 and less than 3, The functional region has multiple defocus regions arranged such that the diameter d1 of other defocus regions within the region falls within ±20% of the diameter d1 of a particular defocus region within the region. In the functional region, the area ratio of the defocus region is 40% or more, in this eyeglass lens.

2. The spectacle lens according to claim 1, wherein the plurality of defocus regions are arranged at intervals without being adjacent to each other.

3. The spectacle lens according to claim 1 or claim 2, wherein the surface shape of the plurality of defocus regions is spherical.

4. The spectacle lens is a farsightedness-reducing lens, as described in any one of claims 1 to 3.

5. A process of designing a base region that causes a light beam incident from the object side to be emitted from the eyeball side and focused through the eyeball to a predetermined position A on the retina, The process includes designing a plurality of defocus regions that have the property of converging the light beam to a position B that is further away from the object than the aforementioned position A, In the process of designing the multiple defocus regions, the diameter d of the circumscribed circle of the triangle connecting the centers of the three nearest defocus regions is used. １ The diameter d of the defocus region ２ The value obtained by dividing by (d １ / d ２ ) becomes greater than 2 and less than 3, A method for designing eyeglass lenses, wherein multiple defocus regions are arranged in a functional region such that the diameter d1 of another defocus region within the region falls within ±20% of the diameter d1 of a particular defocus region within the region, and the area ratio of the defocus regions is designed to be 40% or more.

Images