JP4219352B2 - Double-sided aspherical progressive-power lens - Google Patents

Description

    The present invention is, for example, a lens used as a progressive-power lens for presbyopia for spectacles, and is divided and distributed into a first refractive surface that is an object side surface and a second refractive surface that is an eyeball side surface. A double-sided aspherical surface that has a progressive refractive power action and is configured to give a distance power (Df) and an addition power (ADD) based on a prescription value by combining the first surface and the second surface Type progressive power lens.

    Progressive-power lenses are generally used widely because they are presbyopic eyeglass lenses, but are not easily seen as presbyopia in appearance, and can be clearly visible continuously from long to short distances. ing. However, multiple fields of view, such as a field of view for viewing distant and a field of view for viewing near, and a field for viewing intermediate distances without intervening boundaries in a limited lens area There are disadvantages peculiar to progressive-power lenses, such as the fact that the area of each field of view is not always sufficient, and there are areas that cause image distortion and shaking mainly in the side field of view. Is also widely known.

Various proposals have been made for a long time for the purpose of improving the disadvantages specific to these progressive-power lenses, but the surface configuration of these conventional progressive-power lenses has a "progressive surface" on the object side surface, Most of the combinations had a “spherical surface” or “astigmatic surface” on the eyeball side surface. On the contrary, as a progressive addition lens characterized by adding a “progressive action” to the eyeball side surface, in 1970, Essel Optical Co. There is an Atoral Variplace sold by (currently Essilor).

Moreover, as a prior art proposed in recent years, there exist the technique etc. of patent document 1 and patent document 2, etc., for example, and it is generally called back surface progression (or concave surface progression). The main purpose of the surface composition in this recently proposed rear surface progression is to share a part or all of the required addition power from the object side surface to the eyeball side surface, so that the images of the distance portion and the near portion are imaged. It is intended to reduce magnification differences and improve image distortion and shaking.

Among these prior arts, the one described in Patent Document 1 eliminates all of the “progressive action” by making the object side surface spherical or rotationally symmetric aspherical and gives a predetermined addition power only to the eyeball side surface. A "progressive surface" is added (fused), and the one described in Patent Document 2 reduces the addition power at the "progressive surface" on the object side surface below a predetermined value and gives a short addition power. “Progressive surface” is added (fused) to “spherical surface” and “astigmatism surface” on the back side.

In addition, although there are differences in purpose and grounds, other prior arts of progressive-power lenses described in which a “progressive action” is added to the surface of the eyeball are disclosed in, for example, Japanese Patent Publication No. 47-23934 57-10112, JP-a No. 10-206805, JP include those described in JP 2001 -21846 Patent Publication further similar to that described in WO97 / nineteen thousand three hundred eighty-three No. described above, both surfaces of the lens in the prior art which gave "progressive action", for example, those of JP 2000 -338452 and JP 6-118353 JP. The common point of these prior arts is that the required addition power is shared between the two sides.

The main purpose of these prior arts is to share a part or all of the required addition power from the object side surface to the eyeball side surface, thereby reducing the magnification difference between the distance portion and the near portion, and by the magnification difference. It is intended to improve image distortion and shaking. However, there is little clear description about the grounds for obtaining such improvement effects, and there is only a partial description in the above-mentioned Patent International Publication No. WO97 / 19383 (hereinafter referred to as Prior Art 1). That is, the prior art 1 discloses a formula for calculating the lens magnification SM shown in the following formulas (1) to (3), which is adopted as a basic evaluation parameter for lens design.

That is, the prior art 1 has the following description.
“The lens magnification SM is generally expressed by the following equation.
SM = Mp × Ms (1)
Here, Mp is called a power factor, and Ms is called a shape factor. The distance from the vertex of the lens's eyeball side (inner vertex) to the eyeball is the apex distance L, the refractive power of the inner vertex (inner vertex refractive power) is Po, the thickness of the lens center is t, and the refractive index of the lens is When the base curve (refractive power) of the object side surface of the lens is Pb, it is expressed as follows.
Mp = 1 / (1-L × Po) (2)
Ms = 1 / (1− (t × Pb) / n) (3)
In calculating the equations (2) and (3), diopter (D) is used for the inner vertex power Po and the base curve Pb, and the meter (m) is used for the distance L and the thickness t. "

Then, the difference in magnification between the distance portion and the near portion is calculated using the calculation formula of these lens magnifications SM. Since the magnification difference is small in the prior art 1, the distortion and shaking of the image are improved. Yes.

According to the research of the present inventor, the conventional technique 1 has a certain effect as compared with the prior art. However, in order to design a lens with higher performance, the following points are further examined. It turned out to be necessary.
a. The basic evaluation parameters used in the above-mentioned prior art 1 include the “distance L from the apex of the lens on the eyeball side of the lens to the eyeball” and “lens center thickness t”. In other words, parameters that should be applied only to the vicinity of the center of the lens are included. That is, in the example of the prior art 1, the basic evaluation parameter that should be applied only to the distance portion near the center of the lens is also applied to the near portion located substantially below the lens center. As a result, there remains a possibility of error.

b. In the prior art 1, the lens magnification SM is calculated with five basic evaluation parameters including “lens refractive index n” in addition to the above. However, it is considered that the size of the image is strongly influenced by the “angle between the line of sight and the lens surface”, as can be readily seen by tilting the lens with the power actually back and forth. Therefore, it is considered that this “angle between the line of sight and the lens surface” cannot be ignored particularly in the calculation of the magnification of the near portion located largely below the lens center. Therefore, the lens design of the prior art 1 has a possibility of error due to “calculating the magnification of the lens without considering the angle between the line of sight and the lens surface”.

c. The “magnification” in the prior art 1 has no concept of direction other than the description of the application example to the astigmatic lens. For example, the “magnification between the vertical direction and the horizontal direction that occurs in the near portion located greatly below the lens center”. In the case of “the magnification is different”, there is a possibility of an error due to this.

d. In order to accurately calculate the magnification for the near portion, the distance to the target, that is, the “object distance” must be added as a calculation factor. However, in the prior art 1, this “object distance” is not considered. The possibility of error due to this cannot be denied.
e. Since the influence of the prism action is not considered in the magnification calculation, there is a possibility of an error due to this.
In this way, the prior art has a possibility that it is not always sufficient from the viewpoint of more accurately calculating the “magnification”.

The present invention has been made to solve such a problem, and by taking into consideration the influence of the “angle between the line of sight and the lens surface” and the “objective distance”, by correctly calculating the magnification of the image, the distance portion An object of the present invention is to provide a double-sided aspherical progressive-power lens that reduces the difference in magnification of the image in the near portion and provides a good visual acuity correction with respect to the prescription value and a wide effective field of view with little distortion during wearing.

Furthermore, it is possible to process only the eyeball side surface as a left-right asymmetric curved surface corresponding to the eye convergence in near vision after receiving an order by using a “right and left symmetrical semi-finished product” as the object side surface. An object of the present invention is to provide a double-sided aspherical progressive-power lens capable of reducing the cost.

As means for solving the above-mentioned problem, the first means is:
A double-sided aspherical progressive-power lens having a progressive-power action divided and distributed into a first refractive surface that is an object-side surface and a second refractive surface that is an eyeball-side surface,
The surface astigmatism components at the distance power measurement position F1 and the near power measurement position N1 on the first refractive surface are measured at the distance power measurement position F2 and the near power measurement position N2 on the second refractive surface. Canceling, and combining the first and second refractive surfaces to provide a distance power and addition power based on the prescription value, and the second refractive surface from the distance power measurement position F2 The double-sided aspherical progressive-power lens is characterized in that the surface refractive power in the vertical direction increases toward the near power measurement position N2. More preferably,
The first refracting surface is symmetrical with respect to one meridian passing through the distance power measurement position F1, and the second refracting surface defines the distance power measurement position F2 of the second refracting surface. Double-sided aspherical progressive addition power that is asymmetrical with respect to a single meridian that passes through, and that is disposed at the near power measurement position N2 of the second refracting surface at a predetermined distance. It is a lens.
More preferably,
The first refracting surface is a rotating surface with a meridian passing through the distance power measurement position F1 as a generating line, and the second refracting surface is a distance power measurement position of the second refracting surface. It is asymmetrical with respect to one meridian passing through F2, and the arrangement of the near power measurement position N2 on the second refractive surface is centered on the nose side by a predetermined distance. This is a double-sided aspherical progressive-power lens.
More preferably,
In the configuration in which the first and second refractive surfaces are combined to give the distance power (Df) and the addition power (ADD) based on the prescription value, the line of sight in the wearing state and the lens surface are orthogonal to each other. This double-sided aspherical progressive-power lens is characterized in that the occurrence of astigmatism and the change in power due to the failure are reduced.

According to the above-mentioned means, in the double-sided aspherical progressive-power lens, with respect to the refractive surface on the eyeball side, the surface power in the vertical direction increases from the distance power measurement position to the near power measurement position. In near vision, the distance between the lens surface in the vicinity of the near-use measurement point and the center of the eyeball is close. Therefore, it is possible to provide a progressive-power lens having an effect of improving near vision and excellent wearing feeling.
The above-described means has been devised based on the following elucidation results. Hereinafter, description will be given with reference to the drawings. FIG. 1 is an explanatory diagram of various surface refractive powers at each position on the spectacle lens surface, FIG. 2 is an explanatory diagram of a positional relationship between an eyeball, a line of sight, and a lens, FIG. 3-1, FIG. 3-2 and FIG. FIGS. 4A, 4B, and 4C are explanatory diagrams regarding the magnification Mγ of the prism. The magnification when viewing with the difference between the plus lens and the minus lens and the near portion that is mainly the lower part of the lens. FIG. 5A is an explanatory view of the optical layout of the progressive addition lens, FIG. 5B is a front view of the progressive addition lens viewed from the object side surface, and FIG. 5B is an optical view of the progressive addition lens. FIG. 5C is an explanatory view of the optical layout of the progressive-power lens and an elevation view showing the cross section in the lateral direction, and FIG. It is explanatory drawing which shows the difference in the definition of "addition frequency". In these drawings, symbol F indicates a distance power measurement position, N indicates a near power measurement position, and Q indicates a prism power measurement position. Further, the other reference numerals shown in FIG. 1 and the like pass through the surface refractive power DHf: F at N of the longitudinal sectional curve passing through DVf: F and at the surface sectional power DVn: N passing through DVf: F. This represents the surface refractive power at N of the transverse sectional curve passing through the surface refractive power DHn: N at F of the transverse sectional curve. Furthermore, when the refractive surface in the figure is the first refractive surface that is the object-side surface, the suffix 1 is attached to all symbols, and when the refractive surface is the second refractive surface that is the eyeball-side surface, all symbols Is identified by subscript 2.

Symbols F1 and F2 indicate distance power measurement positions on the object side surface and the eyeball side surface, and similarly N1 and N2 indicate near power measurement positions on the object side surface and the eyeball side surface. Further, E is the eyeball, C is the center of rotation of the eyeball, S is the reference spherical surface centered on C, and Lf and Ln are the lines of sight passing through the distance power measurement position and the near power measurement position, respectively. Further, M is a curve called a main gazing line through which the line of sight passes when viewed from both front and below with both eyes. F1, N1, F2, N2, and N3 indicate portions to which different lens meter openings are applied according to the definition of “additional power”.

First, it corresponds to the near-use part improved by “corresponding the parameter to the near-use part” which is the problem of the above-mentioned conventional technique (a) and “considering the objective distance” which is the problem of (d). The formula for calculating the magnification was obtained as follows. That is, when Mp is a power factor and Ms is a shape factor, an image magnification SM is
SM = Mp × Ms (1 ′)
It is represented by Here, the objective power to the target (the reciprocal of the objective distance expressed in m) is Px, the distance from the eyeball side surface to the eyeball in the near part of the lens is L, and the refractive power (nearly in the near part). When the inner vertex refractive power at the lens portion is Po, the thickness at the near portion of the lens is t, the refractive index of the lens is n, and the base curve (refractive power) of the object side surface at the near portion of the lens is Pb, The following relationship holds.
Mp = (1− (L + t) Px) / (1−L × Po) (2 ′)
Ms = 1 / (1−t × (Px + Pb) / n) (3 ′)

In these equations, if each parameter is made to correspond to the distance portion and 0 corresponding to infinity is substituted for Px which is the power display of the objective distance, the equation of the prior art 1 is matched. That is, it can be considered that the mathematical formula used in the prior art 1 is a special formula for far vision that is an infinite objective distance. Now, (1 ′) is the same as the mathematical formula of the above-mentioned prior art 1, but since the objective distance for near vision is generally about 0.3 m to 0.4 m, the reciprocal Px is −2. It becomes a value of about 5-3.0. Therefore, (2 ') increases Mp because the numerator increases, and (3') decreases Ms because the denominator increases. That is, it can be seen that the influence of the shape factor Ms in near vision is less than the calculation of the conventional technique 1. For example, when Pb = −Px, that is, when the base curve (refractive power) of the surface on the object side of the lens is a value of about +2.5 to +3.0, Ms = 1, and the shape factor in near vision is the image factor. It turns out that it becomes completely unrelated to the magnification.

Now, as described above, each parameter was made to correspond to the near-use part, and a calculation formula for the magnification in consideration of the “object distance” could be obtained, but in order to calculate the magnification in actual near vision, Furthermore, the “angle between the line of sight and the lens surface”, which is the problem of the prior art 1 (b), must be considered. What is important here is that “the angle between the line of sight and the lens surface” has directionality. In other words, taking into account the “angle between the line of sight and the lens surface” is nothing other than taking into account the directionality of the “magnification of image”, which is the problem of the prior art 1 (c).

From this point of view, when reexamining the first calculation formulas (1 ′) to (3 ′) described above, the inner vertex power Po in the near portion and the near power are calculated as a calculation factor influenced by the “angle between the line of sight and the lens surface”. There is a base curve (refractive power) Pb of the object side surface in the use portion. Here, the angle between the line of sight in near vision and the optical axis of the near vision area is α, and the angle between the line of sight in near vision and the normal of the object side surface in the near vision area is β. Using Martin's approximation,
Longitudinal inner power in the near direction:
Pov = Po × (1 + Sin ² α × 4/3)
Lateral inner vertex power in the near part:
Poh = Po × (1 + Sin ² α × 1/3)
Longitudinal cross section refractive power of object side surface at near part:
Pbv = Pb × (1 + Sin ² β × 4/3)
Cross-sectional refractive power of the object-side surface at the near portion:
Pbh = Pb × (1 + Sin ² β × 1/3)
It becomes. Thus, as long as the angles α and β, and Po and Pb are not zero, the refractive power, power factor, shape factor, and the like are different values in the vertical and horizontal directions. As a result, there is a difference in the magnification between the vertical and horizontal directions. It will come.

Here, an approximate expression is used to briefly explain that “the refractive power changes according to the direction of the line of sight”. However, in an actual optical design, these values can be obtained by strict ray tracing calculation. desirable. As non-limiting examples of these calculation methods, for example, the optical path along the line of sight is calculated using Snell's law, and the distances from the object side refractive surface to the object point are calculated, and then By using the first basic form, the second basic form, Weingarten's formula, etc. in differential geometry along the optical path, the influence of refraction on the optical path on the object side refractive surface and the eyeball side refractive surface can be taken into consideration. The refractive power can be calculated. Since these formulas and calculation methods have been known for a very long time, they are described in, for example, the publicly known document “differential geometry” (published by Kentaro Yano (published by Asakura Shoten Co., Ltd., first edition, 1949)), and the description thereof will be omitted.

By performing the exact ray tracing calculation in this way, the four calculation factors L, Po, t, and Pb, which are the problems of the above (a) to (d), are taken into consideration. Strict magnification calculation can be performed in all gaze directions as well as the near-use part located greatly below. In this way,
Longitudinal inner vertex power in the near portion: Pov
Lateral inner vertex power in the near portion: Poh
Longitudinal section refractive power of object side surface at near portion: Pbv
Cross-sectional refractive power of object side surface at near portion: Pbh
Is obtained with higher accuracy than using Martin's approximate expression.

As described above, since “refractive power changes according to the direction of the line of sight”, it can be easily understood that all the above-described image magnification calculations should correspond to the difference in the direction of the line of sight. Here, when Mp is a power factor, Ms is a shape factor, and v is added to the vertical direction and h is added to the horizontal direction, the above-described (1 ') to (3') are described with respect to the image magnification SM. Can be rewritten as follows.
SMv = Mpv × Msv (1v ′)
SMh = Mph × Msh (1h ′)
Mpv = (1− (L + t) Px) / (1−L × Pov) (2v ′)
Mph = (1− (L + t) Px) / (1−L × Poh) (2h ′)
Msv = 1 / (1−t × (Px + Pbv) / n) (3v ′)
Msh = 1 / (1-t × (Px + Pbh) / n) (3h ′)

As described above, the problems (a) to (d) of the prior art 1 can be addressed. Finally, the “influence of the prism action”, which is the above-mentioned problem (e) in calculating the magnification in actual near vision, will be described. The prism itself does not have a refractive power like a lens, but the magnification Mγ of the prism changes depending on the incident angle and the outgoing angle of the light beam to the prism. Here, as shown on the left side of FIG. 3A and FIG. 4A, the angular magnification γ in the case where a light beam incident from a vacuum into a medium having a refractive index n is refracted on the medium surface will be considered. When the incident angle is i and the refraction angle is r, n = Sin i / Sin r according to the well-known Snell's law. The angular magnification γ due to refraction is expressed by γ = Cos i / Cos r. Since n ≧ 1, in general, i ≧ r and γ ≦ 1. Here, γ has a maximum value of 1 when i = r = 0, that is, in the case of normal incidence. Further, when the refraction angle r is n = 1 / Sin r, γ becomes the theoretical minimum value γ = 0. At this time, i = π / 2, and r is equal to the critical angle of total reflection when light rays are emitted from the medium.

On the other hand, as shown on the right side of FIGS. 3-1 and 4-1, the angular magnification γ ′ when a light ray is emitted from a medium having a refractive index n into a vacuum is completely opposite to the above. That is, when the incident angle is i ′ and the refraction angle is r ′ when the light beam is refracted from the inside of the medium and is emitted into the vacuum, Snell's law is 1 / n = Sin i ′ / Sin r ′. The angular magnification is represented by γ ′ = Cos i ′ / Cos r ′. Since n ≧ 1, in general, r ′ ≧ i ′ and γ ′ ≧ 1. Here, γ ′ has a minimum value of 1 when i ′ = r ′ = 0, that is, in the case of normal incidence. Further, when the incident angle i ′ is n = 1 / Sin i ′, γ ′ is the theoretical maximum value γ ′ = ∞. At this time, r ′ = π / 2, and i ′ is equal to the critical angle of total reflection when a light ray is emitted from the medium.

As shown in FIGS. 3-3 and 4-3, a case where a light beam incident on the object side surface of one spectacle lens passes through the inside of the lens, is emitted from the eyeball side surface, and reaches the eyeball (hereinafter described). For the sake of simplicity, the refractive index of air is assumed to be close to 1 as in vacuum). The refractive index of the spectacle lens is n, the incident angle of the light incident on the object side surface is i, the refraction angle is r, the incident angle of the light reaching the eyeball side surface from the inside of the lens is i ′, and the refraction angle of the emitted light. Is r ′, the angular magnification Mγ transmitted through the two surfaces of the spectacle lens is represented by the product of the above-mentioned two types of angular magnifications.
Mγ = γ × γ ′ = (Cos i × Cos i ′) / (Cos r × Cos r ′)
It becomes. This is independent of the refractive power of the lens surface and is known as the magnification of the prism.

Here, as shown in FIGS. 3-1 and 4-1, when i = r ′ and r = i ′,
Mγ = γ × γ ′ = 1
Thus, there is no change in the magnification of the image viewed through the prism. However, as shown in FIG. 3-2, when light rays are incident on the object side surface of the spectacle lens perpendicularly,
Mγ = γ ′ = Cos i ′ / Cos r ′ ≧ 1
On the contrary, as shown in FIG. 4B, when a light beam is emitted vertically from the eyeball side surface of the spectacle lens,
Mγ = γ = Cos i / Cos r ≦ 1
It becomes.

Here, what is important is that the magnification Mγ of these prisms has directionality. That is, when considering the distribution of the prism in the progressive power lens, it is natural that it varies depending on the power and the prescription prism value, but in general there are few prisms in far vision near the center of the lens, and in near vision located below the lens. The vertical prism is large. Therefore, it can be said that the magnification Mγ of the prism has a great influence on the longitudinal direction of near vision.

Considering that not only progressive-power lenses but also spectacle lenses generally have a meniscus shape with a convex surface on the object side and a concave surface on the eyeball side, and the line of sight in near vision is downward. As shown in FIG. 3C, the near vision of the progressive addition lens in which the near portion has a positive refractive power has Mγ ≧ 1 than FIG. 3A in which Mγ = 1. It can be said that at least Mγ> 1. Similarly, as shown in FIG. 4C, the near vision of the progressive addition lens in which the near portion has a negative refractive power has Mγ ≦ 1 as compared to FIG. 4A where Mγ = 1. It is close to the shape of −2, and it can be said that at least Mγ <1. Accordingly, Mγ> 1 in the near vision of the progressive addition lens in which the near portion has a positive refractive power, and Mγ <1 in the near vision of the progressive addition lens in which the near portion has a negative refractive power. Become.

As described above, the lens magnification SM in the prior art 1 was only known as the product of the power factor Mp and the shape factor Ms, whereas in the present invention, the magnification Mγ of the prism is further multiplied to obtain the correct value. The lens magnification is to be obtained.

The magnification Mγ by the prism is referred to as “prism factor” in comparison with Mp and Ms, and is expressed by subscripting v for the vertical direction and h for the horizontal direction. The expressions 1v ′) and (1h ′) can be rewritten as follows.
SMv = Mpv × Msv × Mγv (1v ″)
SMh = Mph × Msh × Mγh (1h ″)
These Mγv and Mγh can be obtained in the above-described strict ray tracing calculation process. Thereby, the problem of the influence by the prism action in the above-mentioned calculation of the magnification of the glasses could be solved.

Now, in a normal convex progressive addition lens, the surface refractive power of the “progressive surface” on the object side surface is the distance portion <the near portion. On the other hand, in the progressive power lens of the prior art 1, the surface refractive power of the “progressive surface” on the object side surface is changed to the distance portion = the near portion, thereby changing the ratio of the shape factor in the distance. The objective is to improve the distortion and shaking of the progressive power lens image by reducing the magnification difference between the near and near images. However, in the consideration in the present invention, by reducing the surface refractive power difference in the perspective of the “progressive surface” on the object side surface, there is an advantage that the difference in magnification of the perspective image in the lateral direction is reduced, but in the vertical direction It has been found that there are several problems in reducing the surface refractive power difference.

The first problem is the influence of the vertical prism factor Mγv. As described above, the longitudinal prism factor Mγv is Mγv <1 when it has a negative refractive power and Mγv> 1 when it has a positive refractive power. It is strengthened by reducing the force difference, and moves away from Mγv = 1, which is the magnification of the naked eye, when the power of the near portion is positive or negative. However, the prism factor Mγh in the horizontal direction has no such influence and Mγh = 1. As a result, there is a vertical and horizontal difference in the magnification of the image particularly from the near portion to the lower portion, and what is supposed to be square in the original is in the positive frequency and in the vertical direction, and in the negative frequency, it is in the horizontal direction. Will occur.

The second problem is a problem that occurs only when the longitudinal direction of the near portion has a positive refractive power. By reducing the surface refractive power difference in the vertical direction, the angle between the line of sight and the lens surface in near vision becomes further oblique, the vertical power factor Mpv increases, and the vertical problem was the first problem. The increase in the prism factor Mγv in the direction and the double effect increase the vertical magnification SMv, which causes a disadvantage that the magnification difference between the near and near images increases.

That is, it has been found that reducing the surface refractive power difference in the near and far sides of the progressive surface, which is the object side surface, has an advantage in the lateral direction, but is rather worse in the longitudinal direction. Therefore, in the conventional convex progressive-power lens, the above-mentioned problem is avoided by dividing the progressive surface, which is the object side surface, into a vertical direction and a horizontal direction, and reducing the difference in near-surface surface refractive power only in the horizontal direction. It can be done.

As described below, the same applies to the fact that “the field of view is widened”, which is generally regarded as an advantage of back surface progression (or concave surface progression).
In general, there is astigmatism at the side of the “progressive surface”, so it is known that there is a limit to the good field of view in the horizontal direction, but the “progressive surface” is placed on the eyeball side surface. For example, the “progressive surface” itself is close to the eye, and there is an advantage that a good field of view spreads in the horizontal direction. However, in the vertical direction, the far field of view is far away, resulting in an inconvenience that the labor for rotating the eyeball from far vision to near vision increases. In other words, the back surface progression (or concave surface progression) has the advantage that the field of view expands in the horizontal direction compared to the conventional surface progression (or convex surface progression), but in the vertical direction, from far vision to near vision. There is a disadvantage that the eyeball rotation angle increases.

However, in the present invention, as described above, there is provided a progressive power surface that satisfies the relational expression of DHf + DHn <DVf + DVn, DHn <DVn, or DVn-DVf> ADD / 2, and DHn-DHf <ADD / 2. Therefore, in the horizontal direction, the back surface progression (or concave progression) feature is stronger than the conventional surface progression (or convex progression) feature, and in the vertical direction, the conventional surface progression (or concave progression) feature is stronger. The feature of progressive (or convex progressive) is strong. Therefore, according to the present invention, while enjoying the advantage that the field of view expands in the horizontal direction, it is possible to suppress the disadvantage that the eyeball rotation angle in the near direction increases in the vertical direction.

Further, in a more extreme example of the category of the present invention, if DVn−DVf = ADD and DHn−DHf = 0, the vertical direction is equivalent to the conventional surface progression (or convex progression), and the horizontal The direction is equivalent to backside progression (or concave progression). Therefore, in this case, the result is very good that the advantage in the horizontal direction can be obtained without the drawbacks in the vertical direction.
Further, as described above, this is the same in reducing the magnification difference between the distance portion and the near portion image and improving the distortion and shaking of the image, and can be said to be an advantage of the present invention.

As described above, the greatest feature of the present invention is that the progressive action of the progressive addition lens is divided into the vertical direction and the horizontal direction of the lens, and the optimal two sides of the front and back are divided in each direction. The ratio is determined and one double-sided aspherical progressive-power lens is formed. For example, as an extreme example, it is also within the scope of the present invention that all of the progressive action in the vertical direction is given on the object side surface and all the progressive action in the horizontal direction is given on the eyeball side surface. In this case, since both the front and back surfaces of the lens do not function as normal progressive surfaces only on one side, the addition power as the progressive surface cannot be specified. That is, the front and back surfaces are progressive lenses that are not progressive surfaces. On the other hand, although the above-mentioned various prior arts have different sharing ratios, all of them assign a "value" of the required addition power to the front and back surfaces and assume a substantially progressive surface that gives each addition power. Above, a composite surface with an astigmatism surface or the like is formed as necessary. In other words, the present invention is decisively different from the above-described prior art in that a double-sided aspherical progressive-power lens using aspherical surfaces having a progressive action different depending on directions is used.

Hereinafter, a double-sided aspherical progressive refraction lens according to an embodiment of the present invention will be described. In the following description, first, the design method used to obtain the double-sided aspherical progressive-refraction lens according to the embodiment will be described, and then the double-sided aspherical progressive-refraction lens according to the embodiment will be described.

(Lens design procedure)
A schematic procedure of the optical design method of the double-sided aspherical progressive-refraction lens according to the embodiment is as follows.
(1) Setting of input information (2) Double-sided design as convex progressive addition lens (3) Conversion to convex shape and accompanying backside correction according to the present invention (4) Backside correction accompanying transmission design, listing rule design, etc. Hereinafter, each procedure will be described in detail by breaking it down into smaller steps.

(1) Setting of input information Input information is roughly classified into the following two types (omitted except for optical design).
(1) -1: Item-specific information Data specific to a lens item. Refractive index Ne of material, minimum center thickness CTmin, minimum edge thickness ETmin, progressive surface design parameters, etc.
(1) -2: Wearer specific information distance power (spherical power S, astigmatism power C, astigmatism axis AX, prism power P, prism base direction PAX, etc.), addition power ADD, frame shape data (three-dimensional shape data is Desirable), frame wearing data (forward tilt angle, tilt angle, etc.), distance between vertices, layout data (distance PD, near CD, eye point position, etc.), and other data relating to the eyeball. The progressive surface design parameters such as the progressive zone length designated by the wearer, the addition power measurement method, and the near-site inset amount are classified as wearer-specific information.

(2) Double-sided design as a convex progressive-power lens First, a conventional convex progressive-power lens is designed by dividing it into a convex surface and a concave surface.
(2) -1: Convex surface shape (convex progressive surface) In order to realize the addition power ADD and progressive band length given as design input information, the surface shape of the conventional convex progression according to the progressive surface design parameter as input information To design. In the design in this step, various conventional known techniques can be used, and the design technique of the present invention is not required.

As a specific example of this method, for example, there is a method of setting a “principal meridian” corresponding to the backbone when the lens surface is first configured. This “main meridian” will ultimately be the “main gaze” that is the intersection of the line of sight and the lens surface when the eyeglass wearer sees both eyes from the front upper (far) to the lower (near). desirable. However, it is not always necessary to perform the alignment of the near region corresponding to the eye convergence action in the near vision by the alignment of the “main gaze” as described later. Accordingly, the “main line of sight” here is defined as a single meridian (main meridian) in the vertical direction that passes through the center of the lens and divides the lens surface into left and right. Since there are two front and back lenses, there are also two “main meridians”. This “principal meridian” looks straight when viewed perpendicular to the lens surface, but when the lens surface is a curved surface, it is generally a curve in a three-dimensional space.

Next, an appropriate refractive power distribution along the “main meridian” is set based on information such as a predetermined addition power and the length of the progressive zone. This refractive power distribution can be divided into two front and back surfaces in consideration of the influence of the lens thickness and the angle between the line of sight and the refracting surface. Since the surface shape is designed, it is assumed that all the progressive actions are on the first refractive surface which is the object side surface. Therefore, for example, when the surface refractive power of the lens surface (first refractive surface that is the object-side surface) is D1, and the surface refractive power of the rear surface of the lens (second refractive surface that is the eyeball-side surface) is D2. If the transmission power obtained is D, it can be approximately obtained as D≈D1−D2. However, the combination of D1 and D2 is preferably a meniscus shape in which the object-side surface is convex and the eyeball-side surface is concave. Note that D2 is a positive value. Normally, the rear surface of the lens is concave, and the surface refractive power has a negative value. However, in this specification, the transmission refractive power D is calculated by subtracting from D1 for the sake of simplicity. And

The relational expression between the surface refractive power and the surface shape is generally defined by the following formula: Dn = (N−1) / R
Here, Dn is the surface refractive power (unit: diopter) of the nth surface, N is the refractive index of the lens material, and R is the radius of curvature (unit: m). Therefore, the method of converting the surface refractive power distribution into the curvature distribution is a modification of the above relational expression.
1 / R = Dn / (N-1)
Is used. By obtaining the distribution of curvature, the geometric shape of the “main meridian” is uniquely determined, and the “main meridian” corresponding to the backbone when the lens surface is constructed is set.

Next, what is needed is a “horizontal cross-sectional curve group” that corresponds to the rib when the lens surface is constructed. The angle at which these “horizontal cross section curve group” and “main meridian” intersect is not necessarily a right angle, but for the sake of simplicity, each “horizontal cross section curve” is “ It shall intersect at right angles on the “main meridian”. Furthermore, the “lateral surface power” of the “horizontal section curve group” at the intersection with the “main meridian” does not necessarily have to be equal to the “vertical surface power” along the “main meridian”. Actually, as described in the claims, the present invention is based on the difference in surface refractive power between the vertical direction and the horizontal direction. However, since the conventional convex progressive surface shape is designed in the design in this step, it is assumed that the surface refractive powers in the vertical direction and the horizontal direction at these intersections are equal.

Now, all “horizontal cross-sectional curves” can be simple circular curves having surface refractive powers at these intersections, but applications incorporating various conventional techniques are also possible. As a prior art example regarding the surface refractive power distribution along the “horizontal cross section curve”, for example, there is a technique disclosed in Japanese Patent Publication No. 49-3595. This sets a single “circular cross-sectional curve” in the vicinity of the center of the lens, and the cross-sectional curve located above it has a surface refractive power distribution that increases from the center to the side, The cross-sectional curve located at is characterized by having a surface refractive power distribution that decreases from the center to the side. In this way, the “main meridian” and the “horizontal cross-sectional curve group” arranged innumerably thereon constitute a lens surface as if it were a spine and a rib, and the refractive surface is determined.

(2) -2: Concave surface shape (spherical surface or astigmatic surface) Design a concave surface shape in order to realize the distance power given as design input information. If the distance power has an astigmatism power, an astigmatism surface is obtained. At this time, the central thickness CT suitable for the power and the inclination angle between the convex and concave surfaces are also designed at the same time, and the shape as a lens is determined. The design in this step can also use various conventional techniques, and does not require the design technique of the present invention.

(3) From the conventional convex progressive addition lens to the shape of the lens of the present invention according to the conversion to the convex surface shape of the present invention and the distance power and addition power ADD given as the back surface correction input information associated therewith Convert.
(3) -1: Convex surface shape (present invention) The conventional convex progressive surface is converted to the convex shape of the present invention in accordance with the distance power or addition power ADD given as design input information. That is, on the surface of the above-described conventional convex progressive lens (the first refractive surface that is the object-side surface), the lateral surface refractive power at the distance power measurement position F1 is DHf, and the vertical surface refractive power is When DVf is the near surface power measurement position N1, the horizontal surface power is DHn, and the vertical surface power is DVn.
DHf + DHn <DVf + DVn and DHn <DVn
Or satisfy the relational expression
DVn-DVf> ADD / 2 and DHn-DHf <ADD / 2
The refractive power surface satisfies the following relational expression. At this time, it is desirable to convert the average surface refractive power of the entire convex surface into the convex shape of the present invention without changing it. For example, it is conceivable to maintain the total average value of the vertical and horizontal surface refractive powers of the distance portion and the near portion. However, it is desirable that the surface on the object side is convex and the meniscus shape in which the eyeball side surface is concave is maintained.

(3) -2: Concave surface shape (present invention) design In (3) -1, the amount of deformation when the conventional convex progressive surface is converted to the convex shape of the present invention is designed in (2) -2. Add to the concave shape. That is, the deformation amount of the lens surface (first refractive surface that is the object-side surface) applied in the process of (3) -1 is transferred to the back surface (second refractive surface that is the eyeball-side surface) side of the lens. Add the same amount. It should be noted that this deformation is similar to “bending” in which the lens itself is bent, but is not a uniform deformation over the entire surface, but a surface that satisfies the relational expression described in (3) -1. These back surface corrections are within the scope of the present invention, but are only linear approximation corrections, and it is desirable to add the back surface correction of (4).

(4) In order to realize the optical function imposed as the backside correction input information associated with the transmission design, the listing rule compatible design, the near-centered internal design, etc. in the situation where the wearer actually wears it, It is desirable to add further back surface correction to the lens of the present invention obtained in (3).
(4) -1: Concave surface shape for transmission design (present invention) Design transmission design is a design method for obtaining an original optical function in a situation where a wearer actually wears a lens. This is a design method for adding a “correcting action” for removing or reducing the occurrence of astigmatism and the change in power caused by the fact that the line of sight and the lens surface cannot be orthogonal.

Specifically, as described above, the difference from the target original optical performance is grasped by strict ray tracing calculation according to the direction of the line of sight, and surface correction is performed to cancel the difference. By repeating this, the difference can be minimized and an optimal solution can be obtained. In general, it is extremely difficult and often impossible to directly calculate a lens shape having a target optical performance. This is because the “lens shape having arbitrarily set optical performance” does not always exist. However, conversely, it is relatively easy to obtain “optical performance of an arbitrarily set lens shape”. Therefore, the first approximate surface is temporarily calculated by an arbitrary method, the design parameters are finely adjusted according to the evaluation result of the optical performance of the lens shape using the approximate surface, and the lens shape is sequentially changed. Thus, it is possible to return to the evaluation step and repeat the reevaluation and readjustment to approach the target optical performance. This method is an example of a widely known method called “optimization”.

(4) -2: Concave surface shape for the design corresponding to the listing rule (the invention of the present application) It is known that the three-dimensional rotational movement of the eyeball when we look around is based on a rule called “listing rule” However, if there is an astigmatism power in the prescription power, even if the astigmatism axis of the spectacle lens is aligned with the "astigmatism axis of the eyeball in frontal view", both astigmatism axes do not match in peripheral vision There is a case. As described above, the “correcting action” for removing or reducing astigmatism and the change in power caused by the astigmatic axis directions of the lens and the eye in peripheral vision are not corrected. It can be added to the curved surface of the surface having the correcting action.

Specifically, in the same manner as the “optimization” method used in (4) -1, the difference from the target original optical performance is grasped by strict ray tracing calculation according to the direction of the line of sight. Perform surface correction to cancel the difference. By repeating this, the difference can be minimized and an optimal solution can be obtained.

(4) -3: Concave shape (invention of the present invention) design for near-centered design corresponding to the near portion Further, the present invention has a double-sided aspherical surface configuration. There is no need to process both sides for the first time. For example, a “semi-finished product” of the object side surface that meets the object of the present invention is prepared in advance, and after the order is received, the object side surface suitable for the purpose such as the prescription frequency or the above custom-made (individual design) It is also advantageous in terms of cost and processing speed to select “semi-finished product” and finish only the eyeball side surface after receiving an order.

As a specific example of this method, for example, the object side surface is prepared in advance as a “semi-finished product” in the convex shape (present invention) design of (3) -1 described above, and the distance between pupils and near vision After the personal information such as the objective distance is input, the near-side portion corresponding to the personal information can be aligned by designing the eyeball side surface as a right and left asymmetric curved surface.

Hereinafter, embodiments of a double-sided aspherical progressive refraction lens designed by the above-described design method will be described with reference to the drawings. FIG. 7 shows “surface refractive power” and “strict magnification calculation results for a specific line-of-sight direction” of the conventional techniques A, B, and C corresponding to Examples 1, 4, 5, and 6, and Table 1-1. FIG. 8 is a table collectively shown in Table 1-2, and FIG. 8 shows “surface refractive power” and “strict magnification with respect to a specific line-of-sight direction” in the conventional techniques A, B, and C corresponding to Examples 2 and 7 and respective frequencies. FIG. 9 is a table summarizing the “calculation results” in Tables 2-1 and 2-2. FIG. 9 is the “surface refractive power” and “specific line of sight” of the prior art A, B, and C corresponding to Example 3 and the frequency FIG. 10 is a graph in which the strict magnification calculation results with respect to the direction are collectively shown in Tables 3-1 and 3-2. FIGS. 10A and 10B are graphs 1-1 and 1-2 showing the surface refractive power distributions of Example 1 and Example 2. , 2-1 and 2-2 are diagrams, FIG. 11 is a diagram illustrating the graphs 3-1 and 3-2 representing the surface refractive power distribution of Example 3, and FIG. FIGS. 13A and 13B show graphs 4-1, 4-2, 5-1, 5-2, 6-1, and 6-2 representing surface refractive power distributions of FIG. FIGS. 14A and 14B are graphs showing graphs 7-1 and 7-2, and FIGS. 14A and 14B are graphs A-1, A-2, B-1, B-2, and C-1 showing surface refractive power distributions of the related art examples A, B, and C, respectively. , C-2.

FIG. 15 shows a result obtained by performing a strict magnification calculation on the magnification distribution when viewing the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight. FIG. 16 is a graph showing a graph 1-3-3-Msv. FIG. 16 shows a strict magnification distribution when the lenses of the three conventional examples A, B, and C corresponding to Example 1 and the frequency thereof are viewed along the main line of sight. FIG. 17 shows a graph 1-3-3-Msh representing the result obtained by performing magnification calculation. FIG. 17 shows the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the frequency along the main line of sight. FIG. 18 is a diagram showing a graph 1-3-3-Mpv showing the result of strict magnification calculation of the magnification distribution when viewed, FIG. 18 shows Example 1 and three conventional examples A and B corresponding to the frequency , C obtained by strict magnification calculation for the magnification distribution when the lens of C is viewed along the main line of sight. FIG. 19 shows a magnification distribution when the lenses of the conventional example A, B, and C corresponding to Example 1 and the frequency thereof are viewed along the main gazing line. FIG. 20 shows a graph 1-3-3-Mγv showing the result obtained by performing strict magnification calculation. FIG. 20 shows the main gaze of the lenses of Example 1 and three conventional examples A, B, and C corresponding to the frequency. FIG. 21 is a diagram showing a graph 1-3-3-Mγh showing a result obtained by performing strict magnification calculation on the magnification distribution when viewed along the line, and FIG. 21 shows Example 1 and three types of conventional examples A corresponding to the frequency. , B, and C show a graph 1-3-3-SMv showing the result of performing a strict magnification calculation of the magnification distribution when viewing the lens along the main gazing line. FIG. Magnification when viewing the lenses of three conventional examples A, B, and C corresponding to the frequency along the main line of sight It is a diagram showing a graph 1-3-SMh representing results of cloth obtained by performing accurate magnification calculations.

FIG. 23 shows a result obtained by carrying out a strict magnification calculation when observing the magnification distribution of Example 2 and the three types of conventional lenses A, B, and C corresponding to the power along the main line of sight. FIG. 24 shows a graph 2-3-3-Msv. FIG. 24 shows the strict magnification distribution when the lenses of the conventional example A, B, and C corresponding to Example 2 and the frequency thereof are viewed along the main line of sight. FIG. 25 shows a graph 2-3-3-Msh representing the result obtained by performing the magnification calculation, and FIG. 25 shows the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency along the main line of sight. FIG. 26 is a diagram showing a graph 2-3-3-Mpv showing the result of strict magnification calculation of the magnification distribution when viewed, FIG. 26 shows Example 2 and three types of conventional examples A and B corresponding to the frequency , C obtained by strict magnification calculation for the magnification distribution when the lens of C is viewed along the main line of sight. FIG. 27 is a graph showing the graph 2-3-3-Mph, and FIG. 27 shows the magnification distribution when the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight. FIG. 28 shows a graph 2-3-3-Mγv showing the result obtained by performing a strict magnification calculation. FIG. 28 shows the main gaze of the lenses of Example 2 and three conventional examples A, B, and C corresponding to the frequency. FIG. 29 is a diagram showing a graph 2-3-3-Mγh showing a result obtained by performing strict magnification calculation on the magnification distribution when viewed along FIG. 29, and FIG. 29 shows Example 2 and three types of conventional examples A corresponding to the frequency , B, and C show a graph 2-3-3-SMv showing the result of performing a strict magnification calculation of the magnification distribution when viewing the lens along the main gazing line. FIG. Magnification when viewing the lenses of three conventional examples A, B, and C corresponding to the frequency along the main line of sight It is a diagram showing a graph 2-3-SMh representing results of cloth obtained by performing accurate magnification calculations.

FIG. 31 shows a result obtained by performing a strict magnification calculation on the magnification distribution when viewing the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight. FIG. 32 is a graph showing the graph 3-3-Msv. FIG. 32 shows a strict magnification distribution when the lenses of the three conventional examples A, B, and C corresponding to Example 3 and the frequency thereof are viewed along the main line of sight. FIG. 33 shows a graph 3-3-Msh representing the result obtained by performing the magnification calculation, and FIG. 33 shows the lenses of Example 3 and three conventional examples A, B, and C corresponding to the frequency along the main line of sight. FIG. 34 shows a graph 3-3-Mpv showing the result of strict magnification calculation of the magnification distribution when viewed, FIG. 34 shows Example 3 and three conventional examples A and B corresponding to the frequency , C obtained by strict magnification calculation for the magnification distribution when the lens of C is viewed along the main line of sight. FIG. 35 is a graph showing a graph 3-3-Mph showing the magnification distribution when the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight. FIG. 36 shows a graph 3-3-Mγv representing a result obtained by performing a strict magnification calculation. FIG. 36 shows the main gaze of the lenses of Example 3 and three conventional examples A, B, and C corresponding to the frequency. FIG. 37 is a diagram showing a graph 3-3-Mγh showing a result obtained by performing a strict magnification calculation of the magnification distribution when viewed along FIG. 37, and FIG. 37 shows Example 3 and three types of conventional examples A corresponding to the frequency , B, and C show a graph 3-3-SMv showing the result of performing a strict magnification calculation of the magnification distribution when viewing the lens along the main gazing line. FIG. Magnification when viewing the lenses of three conventional examples A, B, and C corresponding to the frequency along the main line of sight It is a diagram showing a graph 3-3-SMh representing results of cloth obtained by performing accurate magnification calculations.

Example 1
Table 1-1 in FIG. 7 is a list relating to the surface refractive power of Example 1 according to the present invention. The frequency in Example 1 corresponds to S0.00 Add3.00, and three types of prior art examples of the same frequency are shown for comparison. The conventional example A is a “convex progressive-power lens” in which the object-side surface is a progressive surface, and the conventional example B is “double-sided progressive-power lens in which both the object-side surface and the eyeball-side surface are progressive surfaces. The prior art example C corresponds to a “concave progressive addition lens” whose surface on the eyeball side is a progressive surface. Moreover, the meaning of the item used by Table 1-1 is as follows.
DVf1: Longitudinal surface refractive power DHf1: Horizontal surface refractive power DVn1: Object side surface near power measurement position N1 at the distance power measurement position F1 on the object side surface Surface refractive power DHn1 in the vertical direction at the near-side power measurement position N1 on the object-side surface DVf2: surface refractive power DHf2 in the vertical direction at the distance power measurement position F2 on the eyeball-side surface: eyeball-side surface Lateral power refracting power DVn2 at the distance power measurement position F2 of the eye: Longitudinal power refracting power DHn2 at the near power measurement position N2 of the eyeball side surface: Horizontal surface at the near power measurement position N2 of the eyeball side surface Refractive power

Graphs 1-1 and 1-2 in FIG. 10 are graphs showing the surface refractive power distribution along the main line of sight of Example 1, and the horizontal axis is directed to the right side above the lens, the left side below the lens, The vertical axis represents the surface refractive power. Here, the graph 1-1 corresponds to the object side surface, and the graph 1-2 corresponds to the eyeball side surface. The solid line graph represents the vertical surface power distribution along the main gaze line, and the dotted line graph represents the horizontal surface power distribution along the main gaze line. In the graph 1-1, as shown in the graph, the graph CV1 (solid line) representing the surface refractive power distribution in the vertical direction along the main line of sight on the object side surface has a refractive power distribution in the progressive zone portion to the near portion. However, the graph CH1 (dotted line) representing the surface refractive power distribution in the lateral direction does not change. Further, the graph CV1 (solid line) representing the surface refractive power distribution in the vertical direction and the graph CH1 (dotted line) representing the surface refractive power distribution in the horizontal direction have different surface refractive powers from the progressive zone to the near portion. In this case, astigmatism is generated by the amount of the difference in surface refractive power between the vertical direction and the horizontal direction in the light beam that has optically passed on the main line of sight on the object side surface. On the other hand, in the graph 1-2, as shown in the figure, the graph CV2 (solid line) representing the surface refractive power distribution in the vertical direction along the main gazing line on the eyeball side surface has a refractive power distribution of the distance portion to the progressive portion. There is no change from the belt part to the near part. On the other hand, the graph CH2 (dotted line) representing the surface refractive power distribution in the horizontal direction has different surface refractive powers from the progressive zone to the near portion. Further, the surface refractive power distribution of the graph CV2 (solid line) representing the surface refractive power distribution in the vertical direction and the graph CH2 (dotted line) representing the surface refractive power distribution in the horizontal direction is also a progressive band as in the case of the graph 1-1. It differs from the part to the near part. However, as can be seen from this graph 1-2, the difference in surface refractive power corresponds to the distribution of graph 1-1 in a reverse trend, and the difference in surface refractive power is the main gaze on the eyeball side surface. It can be seen that the astigmatism generated on the object-side surface is given to the light beam that has passed through the line so as to cancel. As a result, the dioptric power and the addition power based on the prescription value can be given by combining the refractive surfaces of the object side surface and the eyeball side surface. Note that these are graphs that explain the basic differences in the surface composition, and are omitted in cases such as making aspherical surfaces to remove astigmatism in the peripheral area and adding astigmatism components to support astigmatism power. is there.

Furthermore, as a graph showing the surface refractive power distribution along the main line of sight of three types of prior art examples of the same power listed in Table 1-1 for comparison, graphs A-1 and 2 and graph B in FIG. -1 and 2 and graphs C-1 and 2 are shown together. The meanings of terms in these graphs are as follows.
F1: Distance power measurement position on the object side surface,
F2: a distance power measurement position on the eyeball side surface N1: a near power measurement position on the object side surface,
N2: Near-field power measurement position CV1 on the eyeball side surface C1: A graph representing the surface refractive power distribution in the vertical direction along the main gaze line on the object side surface (indicated by a solid line)
CH1: A graph representing the surface refractive power distribution in the lateral direction along the main line of sight on the object side surface (indicated by dotted lines)
CV2: graph representing the surface refractive power distribution in the vertical direction along the main line of sight on the eyeball side surface (shown as a solid line)
CH2: A graph representing the surface refractive power distribution in the lateral direction along the main line of sight on the eyeball side surface (indicated by a dotted line)

The surface refractive powers at F1, N1, F2, and N2 in these graphs correspond to those in Table 1-1, and the meanings of terms such as DVf1 to DHn2 are also the same as those in Table 1-1. It is. In addition, the one-dot chain line in the horizontal direction in the center of these graphs indicates the average surface refractive power (total average value of the vertical and horizontal surface refractive powers at F1 and N1) on the object side surface. The average surface refractive power of the object-side surface in Example 1 and the three types of prior art examples according to the present invention is unified to 5.50 diopters.

Next, eight types of graphs beginning with graph 1-3 shown in FIGS. 15 to 22 show the magnification distribution when the lens of Example 1 according to the present invention is viewed along the main line of sight. FIG. 6 is a graph showing results obtained by performing various magnification calculations, in which the horizontal axis faces and the right side is above the lens, the left side is below the lens, and the vertical axis is magnification. In the figure, the dark solid line is Example 1, the thin chain line is Conventional Example A, the dark chain line is Conventional Example B, and the thin solid line is Conventional Example C. This kind of graph below is the same. In addition, while making it possible to compare for each direction of the line of sight using the eyeball rotation angle, the horizontal axis is the scale of the magnification of the vertical axis of each graph. The meaning of the reference signs after the graph 1-3 is
Msv: vertical shape factor,
Msh: shape factor in the horizontal direction Mpv: power factor in the vertical direction
Mph: Power factor in the horizontal direction Mγv: Prism factor in the vertical direction
Mγh: Prism factor in the horizontal direction SMv: Magnification in the vertical direction,
SMh: horizontal magnification, as described above, the vertical magnification SMv and the horizontal magnification SMh are:
SMv = Msv × Mpv × Mγv
SMh = Msh × Mph × Mγh
There is a relationship.

In addition, both Example 1 and the three types of prior art examples have a refractive index n = 1.699, a center thickness t = 3.0 mm, a geometric center GC, and a specification without a prism. Regarding the objective power (reciprocal of objective distance), the objective power Px at F1 and F2 is 0.00 diopter (infinitely far), the objective power Px at N1 and N2 is 2.50 diopter (40 cm), and objectives at other positions are used. The power was given by multiplying the ratio of the additional refractive power along the main line of sight by 2.50 diopters. Further, the distance L from the rear vertex of the lens to the apex of the cornea was set to 15.0 mm, and the distance CR from the apex of the cornea to the center of eyeball rotation was set to 13.0 mm. As for the eyeball rotation angle θ, the eyeball rotation center point C is placed on a normal line passing through the geometric center GC of the object side lens surface, the rotation angle when the normal line and the line of sight coincide with each other is 0 degree, and the upper direction is (+) downward Is indicated by (−). After that, by setting the eyeball rotation angle θ = + 15 degrees for F1 and F2 and unifying the eyeball rotation angle θ = −30.0 degrees for N1 and N2, the progressive action and the distribution of surface refractive power are on either side. It was made possible to compare under the same conditions.

Table 1-2 in FIG. 7 is a list of strict magnification calculation results for a specific line-of-sight direction for Example 1 according to the present invention and three types of conventional technology prepared for comparison. Graph 1-3-3-SMv (total magnification in the vertical direction) and Graph 1-3-SMh (total magnification in the horizontal direction) in FIG. As described above, since the magnification values are different in the vertical direction and the horizontal direction, both magnifications are calculated. Here, the meanings represented by the symbols in Table 1-2 are as follows.
SMvf: Vertical magnification on the line of sight passing through the distance measurement point SMvn: Vertical magnification on the line of sight passing through the near measurement point SMvfn: Vertical magnification difference (SMvn-SMvf)
SMhf: Horizontal magnification on the line of sight passing through the distance measurement point SMhn: Horizontal magnification on the line of sight passing through the near measurement point SMhfn: Horizontal magnification difference (SMhn-SMhf)

Now, looking at SMvfn and SMhfn in Table 1-2, ie, the longitudinal magnification difference (SMvn-SMvf) and the lateral magnification difference (SMhn-SMhf), the prior art example A is 0.1380 and 0.1015, Whereas B is 0.1360 and 0.0988 and C is 0.1342 and 0.0961, the value of Example 1 according to the present invention is held down by a low magnification difference of 0.1342 and 0.0954. I understand that. That is, since the magnification difference between the distance portion and the near portion in the first embodiment according to the present invention is further smaller than that in the prior art 1, the distortion and shaking of the image are further improved as compared with the prior art 1. I understand. In the patent specification corresponding to the above-described prior art 1, the difference between the vertical direction and the horizontal direction is not considered at all in calculating the magnification. However, the graph 1-3SMv (total magnification in the vertical direction) in FIG. 21 and the 1-3-3-SMh (total magnification in the horizontal direction) in FIG. 22 by strict magnification calculation corresponding to Example 1 according to the present invention are obtained. As can be readily seen by comparison, the magnification distributions of the images in the vertical and horizontal directions are clearly different. In addition, it can be easily read that this difference is conspicuous mainly in the near portion and below (the eyeball rotation angle is around −20 ° or less).

Now, the above-mentioned formula for calculating magnification,
Vertical magnification SMv = Msv × Mpv × Mγv
Horizontal magnification SMh = Msh × Mph × Mγh
Graph 1-3-3-SMv is obtained by multiplying the values of three elements, Graph 1-3-Msv, Graph 1-3-Mpv, and Graph 1-3-Mγv. -3-SMh is obtained by multiplying the values of three elements, graph 1-3-Msh, graph 1-3-Mph, and graph 1-3-Mγh. Here, when the vertical and horizontal directions of each element are compared, there is no clear difference between the shape factors Msv and Msv, but Mpv and Mph are below the near part (−25 ° in the eyeball rotation angle). There is a difference in the vicinity). Further, in Mγv and Mγh, there is a remarkable difference between the near portion and the lower portion (the eyeball rotation angle is around −15 ° or less). That is, the main cause of the difference between the graph 1-3SMv and the graph 1-3-3-SMh is the difference between Mγv and Mγh, and the secondary cause is the difference between Mpv and Mph. It can be seen that there is no clear difference and it is almost irrelevant. In other words, the reason why the vertical and horizontal magnification differences are not observed in the patent specification corresponding to the prior art 1 is that the prism factors Mγv and Mγh, which are the main causes of the magnification differences, are not considered at all. Regarding power factors Mpv and Mph which are the next causes, the objective distance and the angle between the line of sight and the lens are ignored, so there is no difference. Further, regarding the shape factors Msv and Msh, which are grounds for improvement in the prior art 1, as long as the scale factors used in the first embodiment of the present invention are viewed, there is no difference between the examples in the perspective magnification difference.

In the prior art 1, “reducing the magnification difference between the distance portion and the near portion” indicates that “the distortion and shaking of the image can be reduced”, but in the present invention, “the magnification difference between the vertical direction and the horizontal direction is further reduced. “Reducing” also has the effect of “reducing image distortion and shaking”. That is, it tries to avoid that a square object looks flat or a round object looks oval. This improvement in visual sensation may be more essential in terms of “making the ratio closer to 1” than “reducing the difference”. What is important here is that the feeling that a square object looks flat or a round object looks oval is not an “perspective ratio” but an “aspect ratio”. That is, in the present invention, not only “reducing the magnification difference between the distance portion and the near portion” but also as an important improvement “by reducing the magnification difference between the vertical direction and the horizontal direction and bringing the magnification ratio closer to 1”. The improvement effect that “the distortion and shaking of the image can be reduced” can be obtained. In addition, these tendencies are conspicuous mainly below the near portion (at an eyeball rotation angle of around −25 ° or less).

(Example 2)
Table 2-1 in FIG. 8 is a list relating to the surface refractive power of Example 2 according to the present invention. The frequency in Example 2 corresponds to S + 6.00 Add3.00, and three types of prior art examples of the same frequency are shown for comparison. The conventional example A is a “convex progressive-power lens” in which the object-side surface is a progressive surface, and the conventional example B is “double-sided progressive-power lens in which both the object-side surface and the eyeball-side surface are progressive surfaces. The prior art example C corresponds to a “concave progressive addition lens” whose surface on the eyeball side is a progressive surface. The meanings of terms such as DVf1 to DHn2 used in Table 2-1 are the same as those in Table 1-1. Graphs 2-1 and 2 are graphs showing the surface refractive power distribution along the main line of sight of Example 2 according to the present invention. The horizontal axis faces the right side above the lens, the left side below the lens and the vertical axis. Represents the surface refractive power. Here, the graph 2-1 corresponds to the object side surface, and the graph 2-2 corresponds to the eyeball side surface. The solid line graph represents the vertical surface power distribution along the main gaze line, and the dotted line graph represents the horizontal surface power distribution along the main gaze line. Note that these are graphs that explain the basic differences in the surface composition, and are omitted in cases such as making aspherical surfaces to remove astigmatism in the peripheral area and adding astigmatism components to support astigmatism power. is there.

Further, as a graph representing the surface refractive power distribution along the main line of sight of the three prior art examples of the same power listed in Table 2-1, for comparison, the graph A-1 used in Example 1 and 2, graphs B-1 and 2 and graphs C-1 and 2 are used again. Therefore, the meanings of the terms in these graphs are the same as those in the first embodiment, but the surface refractive powers in F1, N1, F2, and N2 also correspond to Table 2-1, and are in the center. The average surface refractive power of the object-side surface indicated by the one-dot chain line in the horizontal direction is assumed to be a deep curve of 10.50 diopters in order to correspond to Table 2-1. In graphs 2-1 and 2-2 of FIG. 10, a graph CV1 (solid line) representing the surface refractive power distribution in the vertical direction along the main gaze line on the object side surface, and a graph representing the surface refractive power distribution in the horizontal direction. The distance portion of CH1 (dotted line) and graph CV2 (solid line) representing the surface refractive power distribution in the vertical direction along the main gaze line on the eyeball side surface, and graph CH2 (dotted line) representing the surface refractive power distribution in the horizontal direction The mode of change from the progressive zone to the near portion shows the same tendency as in the first embodiment. From this, it can be seen that the difference in surface refractive power is given so as to cancel the astigmatism generated on the object side surface with respect to the light beam that has passed on the main gaze line on the eyeball side surface. As a result, also in the second embodiment, the dioptric power and the addition power based on the prescription value can be given by combining the refractive surfaces of the object side surface and the eyeball side surface as in the first embodiment. .

Next, eight types of graphs starting with a graph 2-3 shown in FIGS. 23 to 30 show the magnification distribution when the lens of Example 2 according to the present invention is viewed along the main line of sight. It is a graph showing the result calculated by performing various magnification calculations. The terms and the meanings of the symbols attached after the graph 2-3 are the same as in the case of Example 1 except that the dark solid line in the figure is Example 2. The refractive index, objective power, and eyeball rotation angle used in Example 2 and the three types of prior art examples are the same as those in Example 1, but Example 2 and the three types of prior art are the same. Since the frequency of the prior art example is S + 6.00 Add3.00, only the center thickness t is set to 6.0 mm, which is close to an actual product.

Table 2-2 in FIG. 8 is a list of strict magnification calculation results with respect to a specific line-of-sight direction for Example 2 according to the present invention and three types of prior art examples prepared for comparison. It corresponds to −3−SMv (total magnification in the vertical direction) and graph 2-3−SMh (total magnification in the horizontal direction). Here, the meanings represented by the symbols in Table 2-2 are the same as those in Table 1-2.

Now, looking at SMvfn and SMhfn in Table 2-2, that is, the longitudinal magnification difference (SMvn-SMvf) and the lateral magnification difference (SMhn-SMhf), the prior art example A is 0.2275 and 0.1325, Whereas B is 0.2277 and 0.1268, and C is 0.2280 and 0.1210, the value of Example 2 according to the present invention is suppressed to a low magnification difference of 0.2151 and 0.1199. I understand that. That is, the magnification difference between the distance portion and the near portion according to the second embodiment of the present invention is further smaller than that of the prior art 1, and therefore image distortion and shaking are further improved compared to the prior art 1. I understand. Similar to the above-described first embodiment, a graph 2-3SMv (total magnification in the vertical direction) and a graph 2-3-3-SMh (total in the horizontal direction) by strict magnification calculation corresponding to the second embodiment according to the present invention. As can be readily seen by comparing (magnification), the magnification distribution of the image in the vertical and horizontal directions is clearly different.

In addition, it can be easily read that this difference is conspicuous mainly downward from the middle part (in the vicinity of −10 ° or less in eyeball rotation angle). As in the first embodiment, in the second embodiment, the graph 2-3-SMv has three elements, the values of the graph 2-3-3-Msv, the graph 2-3-3-Mpv, and the graph 2-3-3-Mγv. Similarly, graph 2-3-3-SMh is obtained by multiplying the values of three elements, graph 2-3-3-Msh, graph 2-3-3-Mph, and graph 2-3-3-Mγh. Here, when comparing the vertical and horizontal directions of each element, there is no clear difference between the shape factors Msv and Msv, but Mpv and Mph are below the near part (−20 ° in the eyeball rotation angle). There is a difference in the vicinity). In addition, there is a significant difference between Mγv and Mγh from the middle portion downward (eye rotation angle is around −10 ° or less). Here, a difference is also seen above the distance portion (in the vicinity of + 20 ° or more in the eyeball rotation angle), but the difference depending on each example is considerably above the distance portion (in the vicinity of + 30 ° or more in the eyeball rotation angle). Yes, it can be ignored because it is used less frequently.

That is, in the same manner as in Example 1 described above, also in Example 2, the main cause of the difference between the graph 2-3SMv in FIG. 29 and the graph 2-3-3-SMh in FIG. 30 is the difference between Mγv and Mγh. A secondary cause is the difference between Mpv and Mph, and there is no clear difference between Msv and Msh, indicating that they are almost irrelevant. Further, regarding the shape factors Msv and Msh, which are grounds for improvement in the prior art 1, as long as the scale factors used in the second embodiment of the present invention are viewed, there is no difference between the examples in the perspective magnification difference. In the second embodiment, as in the first embodiment described above, not only “reducing the magnification difference between the distance portion and the near portion” but also as an important improvement “the magnification difference between the vertical direction and the horizontal direction”. By reducing the magnification ratio and bringing the magnification ratio close to 1, an improvement effect of “reducing image distortion and shaking” is obtained. In addition, these tendencies are conspicuous mainly below the near portion (at an eyeball rotation angle of around −25 ° or less).

(Example 3)
Table 3-1 in FIG. 9 is a list relating to the surface refractive power of Example 3 according to the present invention. The frequency in Example 3 corresponds to S-6.00 Add3.00, and three types of prior art examples of the same frequency are shown for comparison. The conventional example A is a “convex progressive-power lens” in which the object-side surface is a progressive surface, and the conventional example B is “double-sided progressive-power lens in which both the object-side surface and the eyeball-side surface are progressive surfaces. The prior art example C corresponds to a “concave progressive addition lens” whose surface on the eyeball side is a progressive surface. The meanings of terms such as DVf1 to DHn2 used in Table 3-1 are the same as those in Table 1-1 and Table 2-1.

Graphs 3-1 and 2 in FIG. 11 are graphs showing the surface refractive power distribution along the main line of sight of Example 3 according to the present invention. The horizontal axis faces the right side above the lens, the left side below the lens, The vertical axis represents the surface refractive power. Here, the graph 3-1 corresponds to the object side surface, and the graph 3-2 corresponds to the eyeball side surface. The solid line graph represents the vertical surface power distribution along the main gaze line, and the dotted line graph represents the horizontal surface power distribution along the main gaze line. Note that these are graphs that explain the basic differences in the surface composition, and are omitted in cases such as making aspherical surfaces to remove astigmatism in the peripheral area and adding astigmatism components to support astigmatism power. is there.

Furthermore, as a graph showing the surface refractive power distribution along the main line of sight of the three prior art examples of the same power listed in Table 3-1 of FIG. 9 for comparison, the graph was used in Examples 1 and 2 described above. Graphs A-1 and 2, Graphs B-1 and 2, and Graphs C-1 and 2 are used again. Accordingly, the meanings of the terms in these graphs are the same as those in the first and second embodiments, but the surface refractive powers at F1, N1, F2, and N2 also correspond to Table 3-1, and It is assumed that the average surface refractive power of the object-side surface indicated by the one-dot chain line in the horizontal direction in FIG. In graphs 3-1 and 3-2 of FIG. 11 , a graph CV1 (solid line) representing the surface refractive power distribution in the vertical direction along the main gaze line on the object side surface, and a graph representing the surface refractive power distribution in the horizontal direction. The distance portion of CH1 (dotted line) and graph CV2 (solid line) representing the surface refractive power distribution in the vertical direction along the main gaze line on the eyeball side surface, and graph CH2 (dotted line) representing the surface refractive power distribution in the horizontal direction The mode of change from the progressive zone to the near portion shows the same tendency as in Example 1 and Example 2, and the difference in surface refractive power is due to the light rays that have passed on the main gaze on the eyeball side surface. On the other hand, it can be seen that the astigmatism generated on the object side surface is given to cancel. As a result, the dioptric power and the addition power based on the prescription value can be given by combining the refractive surfaces of the object side surface and the eyeball side surface in the same manner as in the first and second embodiments.

Next, eight types of graphs starting with the graph 3-3 shown in FIGS. 31 to 38 show the magnification distribution when the lens of Example 3 according to the present invention is viewed along the main line of sight. It is a graph showing the result calculated by performing various magnification calculations. The terms and the meanings of the symbols attached after the graph 3-3 are the same as those in the first and second embodiments except that the solid line in the figure is the third embodiment. The refractive index, objective power, eyeball rotation angle, etc. used in Example 3 and the three types of prior art examples are the same as those in Examples 1 and 2, but Examples 3 and 3 Since the frequency of the type of prior art example is S-6.00 Add3.00, only the center thickness t was set to 1.0 mm, which was close to an actual product.

Table 3-2 in FIG. 9 is a list of strict magnification calculation results for a specific line-of-sight direction for Example 3 according to the present invention and three types of prior art examples prepared for comparison. It corresponds to -3-SMv (total magnification in the vertical direction) and graph 3-3SMh (total magnification in the horizontal direction). Here, the meanings represented by the symbols in Table 3-2 are the same as those in Tables 1-2 and 2-2.

Now, looking at SMvfn and SMhfn in Table 3-2, that is, the longitudinal magnification difference (SMvn-SMvf) and the lateral magnification difference (SMhn-SMhf), the prior art example A is 0.0475 and 0.0774, Whereas B is 0.0418 and 0.0750, and C is 0.0363 and 0.0727, the values of Example 2 according to the present invention are values of 0.0512 and 0.0726. It can be seen that the horizontal magnification difference is decreasing, though increasing. However, considering that the vertical magnification difference is a low value such as 1/3 to 1/5 of both the above-described Example 1 and Example 2 and the lateral magnification difference is slightly reduced, It can be said that the magnification difference between the distance portion and the near portion according to the third embodiment of the present invention is not significantly different from that of the related art 1. However, when observing the graph 3-3-SMv (total magnification in the vertical direction) and the graph 3-3-SMh (total magnification in the horizontal direction) by strict magnification calculation corresponding to Example 3 according to the present invention, it is according to the present invention. Compared with the conventional example, Example 3 has the smallest “vertical magnification tends to be smaller than 1” particularly below the near portion (eye rotation angle of about −20 ° or less). The “difference” is the smallest, and the distortion and shaking of the image are improved compared to the conventional example.

Note that in the graph 3-3-SMv (total magnification in the vertical direction) in FIG. 37, the difference in image magnification distribution between the vertical direction and the horizontal direction is downward from the middle part (−10 ° in the eyeball rotation angle). Nearer and below) and above the distance part (eye rotation angle around + 10 ° or more), but the difference in each case is lower than the near part (eye rotation angle around -20 ° or less) and distance use It is slightly above the part (eye rotation angle around + 25 ° or more). Of these, the frequency of use slightly above the distance portion is negligible and can be ignored, but the frequency below the near portion is high and cannot be ignored. As a result, in Example 3 according to the present invention, in comparison with the conventional example, the magnification in the vertical direction is closest to 1 particularly below the near portion (the eye rotation angle is around −20 ° or less). "Is the smallest, and image distortion and shaking are improved compared to the conventional example. In addition, these tendencies are conspicuous mainly below the near portion (at an eyeball rotation angle of around −25 ° or less). In addition, as for the shape factors Msv and Msh, which are grounds for improvement in the prior art 1, as in the case of the first and second embodiments of the present invention, the magnification in the perspective is also seen in the scale used in the third embodiment. There is no difference between the examples.

(Examples 4 to 7)
As an embodiment of the present invention, in addition to the first to third embodiments described above, various surface refractive power distribution combinations are possible within the scope described in the claims. Here, Examples 4 to 6 are shown as application examples of the same degree as Example 1, and Example 7 is shown as an application example of the same degree as Example 2. Lists and graphs of strict magnification calculation results for the surface refractive power and specific line-of-sight direction of these examples are shown in Table 1-1, Table 1-2 in FIG. 7, and Graph 4-1 in FIGS. It shows in graph 4-2 thru | or graph 7-1, graph 7-2. In particular, in Example 7, the lens power is the same as in Example 2, and the same prescription, but as shown in FIGS. 8 and 13, the selection of the curve values of the refractive surfaces on the object side and the eyeball side and It can be seen that a design is disclosed in which the state of change in refractive power on the eyeball side is different from that in the second embodiment. On the object side, compared to the second embodiment, the distance power measurement position adopts a curve having a surface refractive power of 9.00D in both the vertical and horizontal directions and is slightly shallower, but the near power measurement position In the vertical direction, the surface refractive power is a deep curve of 15.00 D, and the horizontal curve is slightly shallower. The tendency of the distribution of refractive power is the same as in Example 2. Next, on the eyeball side, as described above, it can be seen that a design that is clearly different in refractive power distribution and curve is used as compared with Example 2. Compared to Example 2, the distance power measurement position employs a curve having a surface refractive power of 3.00D in both the vertical and horizontal directions, which is slightly shallower, but at the near power measurement position, the vertical direction Has a deep curve with a surface refractive power of 6.00 D, and the curve in the horizontal direction is slightly shallow with a surface refractive power of 0.00 D. However, in the vertical direction, the refractive power distribution is constant in the second embodiment from the distance power measurement position to the near power measurement position, but is changed here and becomes deeper by 3.00 diopters as a curve. ing. That is, the curvature radii of the object side surface and the eyeball side surface both decrease downward. Here, as can be seen from the relationship between the rotation center point C of the eyeball shown in FIG. 6 and the sectional view of the lens, the curvature radii of the object side and eyeball side surfaces of Example 7 are both downward. Smaller means that the near-use part below the lens is closer to the eyeball side. Therefore, it can be seen that the position of the lens in the near vision of Example 7 is closer to the center of eyeball rotation than Example 2.

(Modification)
Furthermore, in the present invention, not only the normal prescription value but also the personal factor of the spectacle wearer, which has been rarely grasped by the lens manufacturer, for example, the distance from the corneal vertex to the rear vertex of the lens, the center of eyeball rotation to the rear of the lens Distance to the apex, degree of unequal image vision of the left and right eyes, difference in height between the left and right eyes, most frequent near vision objective distance, forward tilt angle (vertical direction) and tilt angle (horizontal direction), By incorporating the bevel position in the edge thickness direction of the lens into the lens design as input information, it is possible to meet custom-made (individual design) requirements. Further, although the present invention has a surface configuration of double-sided aspherical surfaces, it is not always necessary to process both sides for the first time after receiving an order in order to obtain the effects of the present invention. For example, a “semi-finished product” of the object side surface that meets the object of the present invention is prepared in advance, and after the order is received, the object side surface suitable for the purpose such as the prescription frequency or the above custom-made (individual design) It is also advantageous in terms of cost and processing speed to select “semi-finished product” and finish only the eyeball side surface after receiving an order.

As a specific example of this method, for example, it is conceivable to prepare in advance a “semi-finished product” on a symmetrical object-side surface. And for near vision inset corresponding to the eye convergence effect in near vision, it corresponds to personal information such as interpupillary distance and near vision objective distance, and asymmetrical left and right for the eyeball side surface It can be incorporated by making it a curved surface. Of course, there are various ways of acquiring and determining information, such as estimation and average / standard values, as well as actual measurement of these personal information, but the present invention is limited by such means. Never happen. In addition to normal prescription values, curved surfaces of the object-side surface, or the eyeball-side surface, or both the object-side surface and the eyeball-side surface when performing optical calculations to incorporate the aforementioned personal factors into the lens design In this case, it is also possible to add a “correction action” for removing or reducing astigmatism and the change in power mainly due to the fact that the line of sight and the lens surface cannot be orthogonal.

Furthermore, it is generally known that the three-dimensional rotational movement of the eyeball when we look around is based on a rule called “listing rule”, but if the prescription power has an astigmatic power, Even if the astigmatism axis is matched with “the astigmatism axis of the eyeball in front view”, the astigmatism axes may not coincide in peripheral vision. As described above, the “correcting action” for removing or reducing astigmatism and the change in power caused by the astigmatic axis directions of the lens and the eye in peripheral vision are not corrected. It is also possible to add to the curved surface of the surface having the correcting action.

The definition of “predetermined addition power” in the present invention is as follows. As shown in FIG. 6, the refractive power measured by applying the aperture of the lens meter to the distance power measurement position F1 and the near power measurement position N1 on the object side surface. In addition to the case of the difference, when the refractive power difference is measured by applying the opening of the lens meter to the distance power measurement position F2 and the near power measurement position N2 on the eyeball side surface, and further, the opening of the lens meter. Is the difference between the refractive power measured by applying to the distance power measurement position F2 on the eyeball side surface and the refractive power measured at N3 toward the near power measurement position N2 by rotating around the center of rotation of the eyeball. In some cases, only the refractive power component in the horizontal direction is used as each refractive power, and any of these definitions can be adopted.

The present invention, for example, is a presbyopic eyeglass lens, but is not easily recognized as presbyopia in appearance, and has the advantage that it can be clearly visible continuously from a long distance to a short distance. Available as a power lens.

It is explanatory drawing of the various surface refractive power in each position of the spectacle lens surface. It is explanatory drawing of the positional relationship of an eyeball, eyes | visual_axis, and a lens. It is explanatory drawing regarding magnification Mγ of a prism, Comprising: It is explanatory drawing regarding the difference between magnifications at the time of seeing using the near part which is mainly the lower part of a lens and the difference between a plus lens and a minus lens. It is explanatory drawing regarding magnification Mγ of a prism, Comprising: It is explanatory drawing regarding the difference between magnifications at the time of seeing using the near part which is mainly the lower part of a lens and the difference between a plus lens and a minus lens. It is explanatory drawing regarding magnification Mγ of a prism, Comprising: It is explanatory drawing regarding the difference between magnifications at the time of seeing using the near part which is mainly the lower part of a lens and the difference between a plus lens and a minus lens. It is explanatory drawing regarding magnification Mγ of a prism, Comprising: It is explanatory drawing regarding the difference between magnifications at the time of seeing using the near part which is mainly the lower part of a lens and the difference between a plus lens and a minus lens. It is explanatory drawing regarding magnification Mγ of a prism, Comprising: It is explanatory drawing regarding the difference between magnifications at the time of seeing using the near part which is mainly the lower part of a lens and the difference between a plus lens and a minus lens. It is explanatory drawing regarding magnification Mγ of a prism, Comprising: It is explanatory drawing regarding the difference between magnifications at the time of seeing using the near part which is mainly the lower part of a lens and the difference between a plus lens and a minus lens. It is explanatory drawing of the optical layout of a progressive-power lens, Comprising: It is the front view which looked at the progressive-power lens from the object side surface. It is explanatory drawing of the optical layout of a progressive-power lens, and is a side view showing the cross section of a vertical direction. It is explanatory drawing of the optical layout of a progressive-power lens, and is an elevational view showing the cross section of a horizontal direction. It is explanatory drawing which shows the difference in the definition of "addition frequency". Tables 1-1 and 1 show "surface refractive power" and "strict magnification calculation results for a specific line-of-sight direction" of the conventional techniques A, B, and C corresponding to Examples 1, 4, 5, and 6, respectively. FIG. Tables 2-1 and 2-2 summarize the “surface refractive power” and “exact magnification calculation results for a specific line-of-sight direction” of the conventional techniques A, B, and C corresponding to Examples 2 and 7 and respective frequencies. FIG. Table 3-1 and Table 3-2 collectively show “surface refractive power” and “strict magnifying power calculation results for a specific line-of-sight direction” of the prior art A, B, and C corresponding to Example 3 and the frequency thereof. FIG. It is a figure which shows the graph 1-1, 1-2, 2-1, 2-2 showing the surface refractive power distribution of Example 1 and Example 2. FIG. FIG. 6 is a diagram illustrating graphs 3-1 and 3-2 representing a surface refractive power distribution of Example 3. It is a figure which shows the graph 4-1, 4-2, 5-1, 5-2, 6-1, 6-2 showing the surface refractive power distribution of Examples 4-6. It is a figure which shows the graphs 7-1 and 7-2 showing the surface refractive power distribution of Example 7. FIG. It is a figure which shows graph A-1, A-2, B-1, B-2, C-1, and C-2 showing the surface refractive power distribution of prior art examples A, B, and C. Graph 1 representing the result obtained by performing strict magnification calculation on the magnification distribution when viewing the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight It is a figure which shows 3-Msv. Graph 1 representing the result obtained by performing strict magnification calculation on the magnification distribution when viewing the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight It is a figure which shows 3-Msh. Graph 1 representing the result obtained by performing strict magnification calculation on the magnification distribution when viewing the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight It is a figure which shows 3-Mpv. Graph 1 representing the result obtained by performing strict magnification calculation on the magnification distribution when viewing the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight It is a figure which shows 3-Mph. Graph 1 representing the result obtained by performing strict magnification calculation on the magnification distribution when viewing the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight It is a figure which shows 3-Mγv. Graph 1 representing the result obtained by performing strict magnification calculation on the magnification distribution when viewing the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight It is a figure which shows 3-Mγh. Graph 1 representing the result obtained by performing strict magnification calculation on the magnification distribution when viewing the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight It is a figure which shows 3-SMv. Graph 1 representing the result obtained by performing strict magnification calculation on the magnification distribution when viewing the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight It is a figure which shows 3-SMh. Graph 2 showing a result obtained by performing a strict magnification calculation on a magnification distribution when the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight It is a figure which shows 3-Msv. Graph 2 showing a result obtained by performing a strict magnification calculation on a magnification distribution when the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight It is a figure which shows 3-Msh. Graph 2 showing a result obtained by performing a strict magnification calculation on a magnification distribution when the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight It is a figure which shows 3-Mpv. Graph 2 showing a result obtained by performing a strict magnification calculation on a magnification distribution when the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight It is a figure which shows 3-Mph. Graph 2 showing a result obtained by performing a strict magnification calculation on a magnification distribution when the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight It is a figure which shows 3-Mγv. Graph 2 showing a result obtained by performing a strict magnification calculation on a magnification distribution when the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight It is a figure which shows 3-Mγh. Graph 2 showing a result obtained by performing a strict magnification calculation on a magnification distribution when the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight It is a figure which shows 3-SMv. Graph 2 showing a result obtained by performing a strict magnification calculation on a magnification distribution when the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight It is a figure which shows 3-SMh. Graph 3 showing a result obtained by performing a strict magnification calculation on the magnification distribution when the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main gazing line. It is a figure which shows 3-Msv. Graph 3 showing a result obtained by performing a strict magnification calculation on the magnification distribution when the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main gazing line. It is a figure which shows 3-Msh. Graph 3 showing a result obtained by performing a strict magnification calculation on the magnification distribution when the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main gazing line. It is a figure which shows 3-Mpv. Graph 3 showing a result obtained by performing a strict magnification calculation on the magnification distribution when the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main gazing line. It is a figure which shows 3-Mph. Graph 3 showing a result obtained by performing a strict magnification calculation on the magnification distribution when the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main gazing line. It is a figure which shows 3-Mγv. Graph 3 showing a result obtained by performing a strict magnification calculation on the magnification distribution when the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main gazing line. It is a figure which shows 3-Mγh. Graph 3 showing a result obtained by performing a strict magnification calculation on the magnification distribution when the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main gazing line. It is a figure which shows 3-SMv. Graph 3 showing a result obtained by performing a strict magnification calculation on the magnification distribution when the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main gazing line. It is a figure which shows 3-SMh.

Claims (1)

A double-sided aspherical progressive-power lens having a progressive-power action divided and distributed into a first refractive surface that is an object-side surface and a second refractive surface that is an eyeball-side surface,
The surface astigmatism components at the distance power measurement position F1 and the near power measurement position N1 on the first refractive surface are measured at the distance power measurement position F2 and the near power measurement position N2 on the second refractive surface. Canceling, and combining the first and second refractive surfaces to provide a distance power and addition power based on the prescription value, and the second refractive surface from the distance power measurement position F2 A double-sided aspherical progressive-power lens, characterized in that the surface refractive power in the vertical direction increases toward the near power measurement position N2.

Images