JP2001318344A - Progressive power lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a progressive power lens in which optical characteristics are made nearly equal in wearing among lenses of different base curves. SOLUTION: The face average refracting power at an arbitrary point on a progressive multifocus surface in a far sight correction region of the first progressive power lens having the first base curve BCL is defined as PfL and the area of the region where PfL-BCL<=0.50 diopter is satisfied is defined as SpL. The face average refracting power at an arbitrary point on a progressive multifocus surface in a far sight correction region of the second progressive power lens having the second base curve BCS and having the substantially the same addition as the addition of the first progressive power lens is defined as PfS and the area of the region where PfS-BCS<=0.50 diopter is satisfied is defined as SpS. The conditions SpL>SpS are satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a progressive multifocal lens, and more particularly, to a progressive multifocal lens used for assisting the accommodation power of the eye.

[0002]

2. Description of the Related Art A single focus lens, a bifocal lens, a progressive multifocal lens, and the like are used for correcting presbyopia. Among these lenses, a progressive multifocal lens, in particular, does not require changing or removing the glasses for far vision and near vision, and does not have a boundary like a bifocal lens in appearance. Accordingly, in recent years, the demand for progressive multifocal lenses has increased considerably.

[0003] A progressive multifocal lens is an auxiliary spectacle lens for accommodation power when the accommodation power of the eye is reduced and near vision becomes difficult. Generally, in a progressive multifocal lens, a far vision correction area (hereinafter, referred to as “above”) located above the lens when worn.
A near vision correction area located below (hereinafter referred to as a "near vision section"), and a progressive area (hereinafter referred to as "a near vision section") in which the refractive power continuously changes between both areas. , “Intermediate part”). In the present invention, notations such as “upper”, “lower”, “horizontal”, and “vertical” indicate the positional relationship of the lens when worn, and for example, the lower part of the distance part is the distance part And the region near the middle portion within the region of FIG.

FIG. 1 is a diagram showing an outline of the area division of a progressive multifocal lens designed symmetrically. The progressive multifocal lens shown in FIG. 1 has a distance portion F which is located above when worn.
, A lower near portion N, and an intermediate portion P whose refractive power changes continuously between both regions. Regarding the shape of the lens surface, the intersection line MM 'between the cross section along the meridian that runs vertically from almost the center of the lens surface upward and downward and the lens surface on the object side (opposite to the eye) is the addition of the lens. It is used as a reference line for indicating specifications, and is also used as an important reference line in lens design. In the progressive multifocal lens thus designed symmetrically, the distance center OF of the distance portion F, the distance eye point E which is a fitting point, the geometric center OG of the lens surface, and the near center ON serve as references. It is on the center line MM '.

FIG. 2 shows a progressive multifocal lens (hereinafter referred to as an “asymmetric progressive multifocal lens”) in which the near portion N is asymmetrically arranged in consideration of the near center ON being closer to the nose side when the lens is worn. "). FIG.
Also, in the asymmetric progressive multifocal lens shown in FIG. 1, the cross section passing through the distance center OF, distance eye point E, the geometric center OG of the lens surface, and the near center ON of the distance portion F and the object-side lens surface also. A center line MM ′ composed of the intersection lines is used as a reference line.

In the present invention, these reference lines are collectively referred to as "main meridian curve". The center of the distance portion F and the center of the near portion N are positions to be references when measuring the lens power. The distance measurement reference point is called a distance center OF, and the near measurement reference point is near. Called center ON. Further, the surface average refractive power at the distance center OF is used as a base curve, and the average spherical power of the transmitted light passing through the distance center OF is a reference average spherical power at the distance portion (hereinafter, referred to as “distance power”). And Normally, the near center ON coincides with the near eye point. However, the distance center and the near center referred to here are not the geometric centers in the respective regions but the functional centers at the time of measurement and wearing of the lens.

In the present invention, the surface average refractive power (hereinafter, referred to as the surface average refractive power)
"Surface refractive power") and surface astigmatism (hereinafter, referred to as "astigmatic difference"), the maximum principal curvature at any point on the progressive multifocal plane is ψmax, the minimum principal curvature is ψmin, Assuming that the refractive index of the lens is n, the following equations (a) and (b)
Respectively. Surface power = (ψmax + ψmin) × (n−1) / 2 (a) Astigmatic difference = (ψmax−ψmin) × (n−1) (b)

In the present invention, the average spherical power and astigmatism are defined as follows: when the maximum spherical power of a light beam transmitted through an arbitrary point on the progressive multifocal plane is Dmax, and the minimum spherical power is Dmin. It is represented by the following equations (c) and (d), respectively. Spherical power = (Dmax + Dmin) / 2 (c) Astigmatism = (Dmax-Dmin) (d)

In the present invention, the average spherical power is hereinafter referred to as "spheric power". Further, in the progressive multifocal lens, a positive surface refractive power (or spherical power) is continuously added from the distance center OF to the near center ON on the principal meridian curve MM 'passing substantially through the geometric center of the lens. Then, the value obtained by subtracting the surface refractive power (or spherical power) of the distance center OF from the surface refractive power (or spherical power) of the near center ON at which the additional surface refractive power (or additional spherical power) becomes almost maximum is obtained. , The addition of a progressive multifocal lens. In the progressive multifocal lens, ideally, a lens which has a wide clear vision area, has little shaking, distortion, etc., and is easy to wear in all areas of the distance portion F, the intermediate portion P, and the near portion N.

[0010]

In the conventional progressive multifocal lens, generally, the optical characteristics of the progressive multifocal plane (refractive surface) have been mainly discussed. That is, the performance of the progressive multifocal lens is often evaluated by, for example, the distribution of surface refractive power and the distribution of astigmatic difference on the progressive multifocal surface. Therefore, in the progressive multifocal plane,
Obtain the distribution of surface refractive power according to the application, ensure a wide area with astigmatic difference less than a predetermined value, so-called clear vision area, and furthermore, the flow of the image when moving your eyes The main purpose has been to minimize the maximum value of the astigmatic difference in consideration of fluctuation, distortion, and the like.

However, in an actual spectacle lens, the optical characteristics of the progressive multifocal plane of the lens do not always match the optical characteristics of the lens when the wearer uses the lens. Therefore, in recent years, in order to further improve the optical performance when the wearer actually uses the lens, not only the optical characteristics of the progressive multifocal plane, but also the evaluation of the optical performance in a state closer to the wearing state, That is, the evaluation of the optical performance by the light beam transmitted through the lens has been started.

In general, the relationship between the lens curvature and the lens power at which the astigmatism of the light beam transmitted through the lens is minimized can be obtained from, for example, a Chernning ellipse. That is, it is well known that by selecting an optimal combination of curvatures obtained by this Chernling ellipse as the curvature of both surfaces of the lens, the occurrence of astigmatism in the peripheral portion of the lens can be suppressed.
However, when an optimal combination of curvatures obtained by this Chernling ellipse is used, the curvature of the base curve tends to be large, and the thickness of the lens tends to be large. For this reason, in recent progressive multifocal lenses, it is a mainstream that a curvature smaller than a curvature obtained by a combination of the above-mentioned optimum curvatures is selected as a base curve from the viewpoint of thinning of the lens, appearance, and manufacturing. Has become.

Therefore, the distribution of the surface refractive power and the distribution of the astigmatic difference in the progressive multifocal plane, and the distribution of the spherical power and the distribution of the astigmatism of the light beam that passes through the lens and enters the wearer's eye. In many cases, the tendency is equal to an area where light rays from an object enter at an angle close to perpendicular to the lens surface, that is, an area near the optical axis of the lens such as near a fitting point of the lens. For it,
Light rays that enter the wearer's eye through positions distant from the optical axis of the lens will enter the lens surface obliquely, so that light rays that pass through a position where the astigmatic difference on the lens surface is almost zero When transmitted through the lens, astigmatism is generated, and the light enters the wearer's eye in a state where the power is shifted from the reference distance power. This trend is
It depends on the curvature of the prescription surface of the lens, the center thickness, and the like, and becomes larger toward the periphery of the lens.

That is, in a progressive multifocal lens having a plurality of base curves, when the surface refractive power and astigmatic difference distribution of the progressive multifocal surface are designed to be equal for each base curve,
The distribution of the spherical power and the distribution of astigmatism of the transmitted light are substantially different for each base curve. Therefore, in order to obtain a series of progressive multifocal lenses having a plurality of base curves and having optical characteristics of transmitted light such as spherical power distribution and astigmatism distribution in the wearing state equal to the plurality of base curves. It is necessary to optimize the progressive multifocal plane in consideration of the production range of each base curve.

Recently, in the progressive multifocal lens, there has been proposed a conventional technique in which the optical performance of the progressive multifocal lens is evaluated by the transmitted light. However, in those prior arts, a region where astigmatism is equal to or less than a predetermined amount, specifically, a region where astigmatism is equal to or less than 0.50 diopter is defined as a clear visual region, and this clear visual region is widely secured. In most cases, only what is done is discussed. That is, the prior art hardly discusses optimization regarding the distribution of spherical power.

It is important and necessary to keep astigmatism to a small amount as a criterion for defining the clear vision zone. However, it is not sufficient to define the clear visual field only by the magnitude of astigmatism for a far vision part that requires a particularly wide field of view in daily life. That is, in a region where the spherical power is greatly shifted from the distance power by prescription, even if the astigmatism is equal to or less than a predetermined amount which is generally defined as a clear vision zone, the image is blurred due to the power shift. One cannot clearly see the object in far vision. The influence of the power deviation in the distance portion for performing far vision is greater than the effect of the power deviation in the near portion for performing near vision. For this reason, it is very important to design the distance portion in consideration of the power deviation from a predetermined distance power, as compared with the near portion.

The present invention has been made in view of the above-mentioned problems, and has been made in consideration of a series of progressive multifocal lenses having a plurality of base curves designed so that the basic specifications of the lenses are substantially equal. The optical characteristics on wearing can be made almost equal to the base curve of
It is an object of the present invention to provide a progressive power multifocal lens capable of favorably setting optical performance in a wearing state. SUMMARY OF THE INVENTION It is an object of the present invention to provide a progressive multifocal lens capable of securing a wide clear vision region with small astigmatism and small image blur due to power deviation, particularly in a distance portion.

[0018]

According to a first aspect of the present invention, a refracting surface of a lens is divided into a nasal region and an ear region at least on one surface of the lens. Along the meridian curve, the distance vision correction area corresponding to the distant view, the near vision correction area corresponding to the near view, and the surface of both areas between the distance vision correction area and the near vision correction area. A series of progressive multifocal lenses having a plurality of base curves, wherein the plurality of base lenses have a progressive area continuously connecting refractive power, and are designed such that basic specifications of the lenses are substantially equal. in the first progressive power multifocal lens having a first base curve BC _L selected from a curve, the average surface refracting power of an arbitrary point on the progressive power multifocal surface in the far vision correction area and Pf _L, Pf _L - BC _L ≦ 0.
The area of the region satisfying 50 diopters is Sp _L ,
A second base curve BC _S which curvature than said first base curve BC _L is selected from substantially small and the plurality of base curves, the first progressive addition diopter focus lens substantially the same in the second progressive power multifocal lens having a diopter, the average surface refracting power of an arbitrary point on the progressive power multifocal surface in the far vision correction area and Pf _S, Pf _S -BC
_The area of the region satisfying _S ≦ 0.50 diopter is Sp _S
And a progressive multifocal lens characterized by satisfying the following condition: Sp _L > Sp _S (1).

According to the second aspect of the present invention, a distance vision correction corresponding to a distant view is provided on at least one surface of the lens along a principal meridian curve dividing the refractive surface of the lens into a nose side region and an ear side region. A region, a near vision correction region corresponding to the near view, and a progressive region that continuously connects the refractive powers of the surfaces of both regions between the distance vision correction region and the near vision correction region, basic lens specifications of designed to be substantially equal to a series of progressive multifocal lenses having a plurality of base curves, the having a first base curve BC _L selected from said plurality of base curves in one progressive multifocal lens, the area of the region surface astigmatism in the far vision correction area is not more than 0.50 diopters and Sa _L, curvature than said first base curve BC _L is substantially smaller and The plurality The second, which is selected from Sukabu
Has a base curve BC _S, in the second progressive multifocal lens having addition power and substantially the same addition power of the first progressive multifocal lens, the surface astigmatism in the far vision correction area is 0.50 The area of the region that is less than diopter is Sa
When the _S, provides a progressive multifocal lens that satisfies the conditions of _{Sa L <Sa S (2)} .

According to the third aspect of the present invention, at least on one surface of the lens, a distance vision correction corresponding to a distant view is provided along a main meridian curve dividing the refractive surface of the lens into a nose side region and an ear side region. A region, a near vision correction region corresponding to the near view, and a progressive region that continuously connects the refractive powers of the surfaces of both regions between the distance vision correction region and the near vision correction region, basic lens specifications of designed to be substantially equal to a series of progressive multifocal lenses having a plurality of base curves, the having a first base curve BC _L selected from said plurality of base curves in one progressive multifocal lens, the average surface refracting power of an arbitrary point on the progressive power multifocal surface in the far vision correction area and Pf _L, Pf _L -BC
_The area of the region satisfying _L ≦ 0.50 diopters is Sp _L
And the plane astigmatism in the distance vision correction area is 0.5
0 The area of the region is diopter or less and Sa _L, a second base curve BC _S which curvature than said first base curve BC _L is selected from substantially small and the plurality of base curves, the first In a second progressive multifocal lens having substantially the same addition as the one progressive multifocal lens, the surface average refractive power of an arbitrary point on the progressive multifocal plane in the distance vision correction area is defined as Pf _S. , Pf _S -BC _S
The area of the region satisfying ≦ 0.50 diopter is Sp _S
And the plane astigmatism in the distance vision correction area is 0.5
0 when the area of the region is diopter or less was Sa _S, provides _{Sp L> Sp S (1)} Sa L < progressive multifocal lens that satisfies the conditions of Sa _S (2).

[0021] According to a preferred embodiment of the first to third aspects of the invention, the progressive in a region located above the geometric center OG of the multifocal lens, the first progressive multifocal lens having a first base curve BC _L Any point on the isosurface astigmatism curve whose surface astigmatism is 0.50 diopter is denoted by M _L
And then, the geometric center vertical height from OG to said arbitrary point M _L when the main meridian horizontal distance from the curve to the arbitrary point M _L is x (mm) and h _L, any point on the second progressive surface astigmatism of multifocal lens is 0.50 diopters Hitoshimen astigmatism curve having a second base curve BC _S and M _S, the optionally from said principal meridional curve horizontal distance to M _S point is x (mm)
Assuming that the height in the vertical direction from the geometric center OG to the arbitrary point M _S at the time of is h _S , the condition of h _L > h _S (3) is satisfied in a region satisfying 15 ≦ | x | Always satisfied.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, in the prior art, an area in which astigmatism is smaller than a predetermined amount, specifically, an area in which astigmatism or astigmatism is within 0.50 diopters is defined. Although it is defined as a viewing zone, it is not sufficient to define a clear viewing zone based on such a condition, particularly in a distance portion. Therefore, in the present invention, it is considered important to suppress the deviation amount of the spherical power from the distance power to a small value in a wide range, and the astigmatism is smaller than a predetermined amount and the distance power of the spherical power is small. Is defined as a clear vision region, that is, a region in which the amount of deviation from is smaller than a predetermined amount, that is, a region that satisfies both conditions of astigmatism and spherical power. In the prior art, no progressive multifocal lens optimized to simultaneously satisfy these two conditions in a wide range of the distance portion has not been proposed.

A general progressive multifocal lens has a plurality of base curves within a manufacturing range from a positive intensity number to a negative intensity number. Originally, it is most preferable for the wearer to be able to have an optimal progressive multifocal surface for each distance power. However, in consideration of manufacturing convenience and cost advantages, usually a predetermined distance power is used. , The same progressive multifocal plane is shared.

Generally, among a plurality of base curves,
The base curve requires a larger curvature in the manufacturing range where the distance power has a more positive strength, whereas the curvature of the base curve becomes smaller in the manufacturing range where the distance power has a more negative strength. Therefore, in order to obtain the optical performance of the transmitted light beam that meets the equal design specifications within the manufacturing range manufactured using these equal progressive multifocal surfaces, the refractive surface of the progressive multifocal lens having a plurality of base curves is required. It is necessary to optimize the optical characteristics according to the respective manufacturing ranges and the curvature of the base curve.

In the present invention, a base curve corresponding to a manufacturing range including a distance power of 0.00 diopter is set as a reference base curve, a progressive multifocal plane in the reference base curve is set as a reference design, and a spherical surface in this reference design is used. Optical performance on wearing such as power distribution and astigmatism distribution,
It is the goal of optical performance in all base curve progressive multifocal lenses.

When the optical characteristics of the progressive multifocal surface (refractive surface), for example, the surface refractive power distribution and the astigmatic difference distribution are designed to be equal to the reference design in the base curve in the manufacturing range where the distance power is stronger, The distribution of spherical power and astigmatism due to transmitted light greatly differs from the distribution of spherical power and astigmatism in the reference design. In other words, from the viewpoint of the optical characteristics of the refractive surface such as the surface refractive power and the astigmatic difference, these multiple base curve lenses appear to be progressive multifocal lenses based on the same design, but the spherical power distribution of the transmitted light rays. In terms of optical characteristics in the wearing state such as distribution of astigmatism and astigmatism distribution, the lens becomes different.

Therefore, in the present invention, the distribution of the surface refractive power and the distribution of the astigmatic difference in the progressive multifocal plane are determined by a certain law depending on the base curve corresponding to the production range of each distance power. Is changed. With this configuration, in the progressive multifocal lens of each base curve, the optical characteristics in the wearing state such as the spherical power distribution and astigmatism distribution of the transmitted light are made equal, and the astigmatism is small and the power is low in the distance portion. It is possible to secure a wide clear vision area with less image blur due to displacement.

In the present invention, it is required that the spectacle lens wearer see an object at a distance of at least 2 m without perceiving blurring of the image under the minimum condition in the spherical power of the clear vision region in the far vision. I think there is. Therefore, the absolute value of the deviation of the spherical power from the distance power at an arbitrary point on the progressive multifocal plane of the distance portion is within 0.50 diopter, which is related to the spherical power in the clear vision zone of the present invention. This is a condition (that is, a condition relating to frequency deviation). Regarding astigmatism, the amount of astigmatism that can be seen without feeling the flow of the image in far vision is
Since it is generally set to 0.50 diopter, the condition regarding astigmatism in the clear vision region of the present invention is that the astigmatism is 0.50 diopter or less.

By the way, in a series of progressive multifocal lenses having a plurality of selectable base curves, if the surface refractive power distributions of two lenses each having a base curve having a different curvature are substantially equal, the curvature of the base curve becomes larger. Since the area of the region where the spherical power is equal to or less than the predetermined value in the distance portion becomes smaller, the clear viewing area of the distance portion becomes smaller. On the other hand, as the curvature of the base curve becomes smaller, the area where the spherical power in the distance portion is equal to or less than a predetermined amount becomes larger, but the negative spherical power is added in the peripheral portion of the distance portion, resulting in a negative overcorrected area. Can be. As a result, the clear vision region in the distance portion becomes narrower, or the region satisfying the spherical power according to the prescription expands to the intermediate portion, so that the region of the spherical power that should be originally added to the intermediate portion or the near portion becomes narrower. This causes problems such as a narrowing of a practical intermediate portion and a near portion.

Therefore, in the first invention, the area Sp of the region where the difference between the surface refractive power Pf and the base curve BC in the distance portion on the progressive multifocal plane is 0.50 diopters or less is:
By configuring so as to satisfy the conditional expression (1), the optical performance in the distance portion is improved, the wide clear vision range is ensured, and the progressive multifocal lenses having different base curves are used. On the other hand, the optical characteristics on wearing can be made almost equal.

In a series of progressive multifocal lenses having a plurality of selectable base curves, if the astigmatism distributions of two lenses having base curves having different curvatures are substantially equal, the curvature of the base curve becomes larger. In either case, the area where the astigmatism in the distance portion is smaller than or equal to a predetermined value becomes narrower, so that the clear vision area of the distance portion becomes narrower. At this time, in the first progressive multifocal lens having a larger curvature of the base curve, the area Sa _L of the region where the astigmatic difference of the progressive multifocal plane in the distance portion is 0.50 diopter or less is determined by the progressive multifocal lens of the reference design. When the area where the astigmatism of the focal plane is 0.50 diopters or less is smaller than the area Sa ₀ , a wide area where the astigmatism in the transmitted light is 0.50 diopters or less can be secured.

On the other hand, in the case of the second progressive multifocal lens having a smaller base curve curvature than that of the first progressive multifocal lens, the area of the region where the astigmatic difference of the progressive multifocal plane is 0.50 diopters or less. By expanding Sa _S , it is possible to secure a wide area where the astigmatism of the transmitted light in the distance portion is 0.50 diopters or less. Therefore, in the second invention, the area S of the region where the astigmatism difference in the distance portion on the progressive multifocal plane is 0.50 diopter or less is obtained.
When a is configured so as to satisfy the conditional expression (2), the optical performance in the distance portion is improved, the wide clear vision range is secured, and the progressive multifocal lenses having different base curves are used. The optical characteristics on wearing can be made substantially equal to the base curve.

Further, in the third invention, the difference between the surface refractive power Pf and the base curve BC at the distance portion on the progressive multifocal plane is 0.50 diopter by the combination of the first invention and the second invention. The area Sp of the following region and the astigmatic difference in the distance portion on the progressive multifocal plane are 0.50
By configuring so that the area Sa of the region which is equal to or less than diopter satisfies the conditional expressions (1) and (2), the optical performance in the distance portion is improved, and the base curve is widened while securing a clear vision region. Of different progressive multifocal lenses can be made to have substantially the same optical characteristics on wear for all base curves.

Further, in the first to third aspects of the present invention, the condition that the conditional expression (3) is satisfied in a region 15 mm or more in the horizontal direction from the main meridian curve allows clear vision in the distance side portion. It is possible to make the astigmatism distribution substantially equal between progressive multifocal lenses having different base curves while securing a wide area. This conditional expression (3)
Deviates from the range, especially in a progressive multifocal lens having a small curvature of the base curve, the astigmatism of the side portion for far vision deteriorates. As a result, a progressive multifocal lens having a small curvature of a base curve is not preferable because a clear vision area becomes narrower than a progressive multifocal lens having a large base curve.

It should be noted that 15 m from the main meridian curve in the horizontal direction.
In a region near the distance eye point within m, the tendency of the surface astigmatism distribution and the tendency of the astigmatism distribution are close. For this reason, it is desirable that the conditional expression (3) of the present invention be satisfied in a region that is at least 15 mm or more away from the main meridian curve in the horizontal direction. However, in the present invention, it is needless to say that it is more preferable to satisfy the conditional expression (3) in a region separated by 10 mm or more in the horizontal direction.

An embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 3 is a diagram showing a surface addition average refractive power (hereinafter, referred to as a reference value) of a progressive multifocal lens which is a reference design in the embodiment of the present invention.
FIG. 6 is a distribution diagram of “surface additional refractive power”). FIG.
FIG. 4 is an astigmatic difference distribution diagram of a progressive multifocal lens according to the reference design of the present embodiment.

In the progressive multifocal lens which is the reference design of this embodiment, the outer diameter φ is 70 mm, the base curve BC is 3.10 diopters, and the distance power Df is
0.00 diopter, addition is Ad = 2.00 diopter, the refractive index of the lens is ne = 1.50, and the position of the distance eye point E is the geometric center OG of the lens.
The distance center OF is located 8 mm above the geometric center OG of the lens.

Here, the surface additional power is the surface power obtained by subtracting the base curve from the surface average power at an arbitrary point on the progressive multifocal plane. In this embodiment, for the sake of simplicity, the surface added power distribution will be used to discuss the surface added power distribution, but the surface added power and the surface average refractive power have essentially the same meaning.

On the other hand, FIG. 5 is a distribution diagram of an additional average spherical power (hereinafter, referred to as “additional spherical power”) in the transmitted light of the progressive multifocal lens according to the reference design of the present embodiment. FIG. 6 is an astigmatism distribution diagram of a transmitted light of the progressive multifocal lens according to the reference design of the present embodiment. Here, the additional spherical power is a spherical power obtained by subtracting the distance power of a light beam passing through the distance center OF from the spherical power of a light beam passing through an arbitrary point on the progressive multifocal plane. In this embodiment,
For the sake of simplicity, the spherical power distribution will be discussed with this additional spherical power distribution, but the essential meanings of the additional spherical power and the spherical power are the same.

In the progressive multifocal lens according to this embodiment, the optical performance of the transmitted light in the reference design with the reference base curve BC = 3.10 diopters is regarded as the basic optical performance. For this reason, in the present embodiment, even in a progressive multifocal lens having another base curve, the additional spherical power distribution and astigmatism distribution are changed in the progressive multifocal lens of the reference design as shown in FIGS. The design goal is to approach the additional spherical power distribution and the astigmatism distribution.

FIG. 7 is a surface additional refractive power distribution diagram of a progressive multifocal lens as a first comparative example with respect to the reference design of the present embodiment. FIG. 8 is an astigmatic distribution diagram of the progressive multifocal lens according to the first comparative example. In the progressive multifocal lens according to the first comparative example, the surface additional refractive power distribution and the astigmatic difference distribution are almost the same as the surface additional refractive power distribution and the astigmatic difference distribution of the progressive multifocal lens according to the reference design of the present embodiment. Designed to be equal.

In the progressive multifocal lens according to the first comparative example, the outer diameter φ = 70 mm, and the base curve BC = 5.
60 diopters, the distance power Df = + 3.50 diopters, the addition power Ad = 2.00 diopters, the refractive index of the lens ne = 1.50, and the position of the distance eye point E is It is located 2 mm above the geometric center OG, and the distance center OF is 8 mm above the geometric center OG of the lens.
mm above. As described above, the reference curve of the present embodiment and the first comparative example are different in the base curve and the distance power. However, comparing FIGS. 3 and 4 with FIGS. 7 and 8, it can be seen that the surface additional refractive power distribution and the astigmatic difference distribution are substantially equal, even though the curvatures of the base curves are different.

FIG. 9 is an additional spherical power distribution diagram of the transmitted light of the progressive multifocal lens according to the first comparative example. As described above, in the first comparative example, the surface additional refractive power distribution is substantially equal to the reference design of the present embodiment. However, comparing FIGS. 5 and 9 with reference to FIGS.
It can be seen that the area of 50 diopters or less is narrower than the reference design of the present embodiment, especially in the distance side area. Therefore, in the first comparative example, the distance eye point E
, The wearer can only see far in this narrow area, especially in the horizontal direction. In other words, in the first comparative example, the clear vision area in the distance portion is narrow.

FIG. 10 is a diagram showing the astigmatism distribution in the light beam transmitted by the progressive multifocal lens according to the first comparative example. As described above, in the first comparative example, the astigmatism difference distribution is almost equal to the reference design of the present embodiment. However, comparing FIG. 6 and FIG. It can be seen that the area below the diopter is narrower than the reference design of the present embodiment, and the astigmatism is significantly degraded especially above the distance portion. For this reason, in the first comparative example, the clear vision area in the distance portion is narrowed.

As described above, referring to FIG. 9 and FIG. 10, in the progressive multifocal lens of the first comparative example having a base curve having a larger curvature than the reference design of the present embodiment, the surface addition of the progressive multifocal surface When the refractive power distribution and the astigmatic difference distribution are made substantially equal to those of the reference design of the present embodiment, an area where the additional sphere power of the transmitted light is 0.50 diopter or less and the astigmatism is 0.50 diopter or less in the present embodiment. It can be seen that it becomes much narrower than the reference design. Therefore, the progressive multifocal lens of the first comparative example has a very narrow clear vision area in the distance portion, and has poor optical performance different from the reference design of the present embodiment.

FIG. 11 is a surface additional refractive power distribution diagram of a first progressive multifocal lens which is a progressive multifocal lens according to the present embodiment and has a base curve having a larger curvature than the reference design. In the first progressive multifocal lens according to the present embodiment, similarly to the first comparative example, the outer diameter φ is 70 mm, the base curve BC is 5.60 diopters, and the distance power Df is +3.50 diopters. Yes, additional power Ad =
2.00 diopters and the refractive index of the lens ne =
1.50, the distance eye point E is located 2 mm above the lens geometric center OG, and the distance center OF is located 8 mm above the lens geometric center OG.

As can be seen from a comparison between FIG. 3 and FIG.
In the first progressive multifocal lens of the present embodiment, the area of the region where the surface additional refracting power is 0.50 diopter or less in the distance portion is wider than in the standard design. Further, in the first progressive multifocal lens of the present embodiment, a negative surface refractive power is added to the base curve in the peripheral portion of the lens above the distance center OF of the distance portion.

FIG. 12 is an astigmatic difference distribution diagram of the first progressive multifocal lens according to this embodiment. As can be seen from a comparison between FIG. 4 and FIG. 12, in the first progressive power multifocal lens of the present embodiment, the area of the region where the astigmatic difference is 0.50 diopter or less in the distance portion is smaller than that in the case of the reference design. And especially narrow in the distance side region.

FIG. 13 is an additional spherical power distribution diagram of a transmitted light beam of the first progressive multifocal lens according to the present embodiment. As can be seen from the comparison between FIG. 9 and FIG. 13, in the first progressive multifocal lens of the present embodiment, the area where the additional spherical power is 0.50 diopter or less in the distance portion is the surface refraction of the progressive multifocal plane. The force distribution is much wider than in the case of the first comparative example in which the force distribution is almost equal to the reference design of the present embodiment, and particularly wide in the distance side portion. As a result, as can be seen from the comparison between FIG. 5 and FIG. 13, the first progressive power multifocal lens of the present embodiment has an additional spherical power closer to the additional spherical power distribution of the progressive multifocal lens according to the reference design of the present embodiment. It is a distributed lens.

FIG. 14 is a diagram showing the astigmatism distribution of the transmitted light beam of the first progressive multifocal lens according to this embodiment.
As can be seen from a comparison between FIG. 10 and FIG. 14, in the first progressive multifocal lens of the present embodiment, the region where the astigmatism is 0.50 diopters or less in the distance portion is the astigmatism of the progressive multifocal plane. The difference distribution is much wider especially in the upper part of the lens than in the first comparative example in which the difference distribution is almost equal to the reference design of the present embodiment. As a result, as can be seen from a comparison between FIG. 6 and FIG. 14, the first progressive multifocal lens of the present embodiment has an astigmatism closer to the astigmatism distribution of the progressive multifocal lens according to the reference design of the present embodiment. It is a distributed lens.

As described above, with reference to FIG. 13 and FIG. 14, the present embodiment has a base curve having a larger curvature than the reference design of the present embodiment, and corresponds to a manufacturing range in which the distance power is more positive. In the first progressive multifocal lens of the form,
In the distance portion, a clear viewing area with an additional spherical power of 0.50 diopter or less and an astigmatism of 0.50 diopter or less can be secured widely, and can be close to the optical performance on wearing in the reference design of the present embodiment. .

FIG. 15 is a surface additional refractive power distribution diagram of a progressive multifocal lens as a second comparative example with respect to the reference design of the present embodiment. FIG. 16 is an astigmatic difference distribution diagram of the progressive multifocal lens according to the second comparative example. In the progressive multifocal lens according to the second comparative example, the surface additional refractive power distribution and the astigmatic difference distribution are almost the same as the surface additional refractive power distribution and the astigmatic difference distribution of the progressive multifocal lens according to the reference design of the present embodiment. Designed to be equal.

In the progressive multifocal lens according to the second comparative example, the outer diameter φ = 70 mm, and the base curve BC = 2.
00 diopter, the distance power Df = −2.50 diopter, the addition power Ad = 2.00 diopter, the refractive index of the lens ne = 1.50, and the position of the distance eye point E is Is located 2 mm above the geometric center OG of the lens, and the distance center OF is 8 mm above the geometric center OG of the lens.
mm above. As described above, the base curve and the distance power are different between the reference design of the present embodiment and the second comparative example. However, comparing FIGS. 3 and 4 with FIGS. 15 and 16, it can be seen that even if the curvatures of the base curves are different, the surface additional refractive power distribution and the astigmatic difference distribution are substantially equal.

FIG. 17 is an additional spherical power distribution diagram of transmitted light rays of the progressive multifocal lens according to the second comparative example.
As described above, in the second comparative example, the surface additional refractive power distribution is substantially equal to the reference design of the present embodiment, and the region where the additional spherical power is 0.50 diopter or less in the distance portion is the present embodiment. Is wider than the reference design.
However, comparing FIG. 5 with FIG.
In the comparative example, it can be seen that the area of the spherical power to be originally added to the intermediate portion or the side portion of the near portion is narrower than the reference design of the present embodiment.

FIG. 18 is a diagram showing the astigmatism distribution of the transmitted light of the progressive multifocal lens according to the second comparative example. As described above, in the second comparative example, the astigmatism difference distribution is almost equal to the reference design of the present embodiment. However, comparing FIG. 6 and FIG. It can be seen that the area below the diopter is narrow only near the distance center OF. In the second comparative example,
It can be seen that the astigmatism is large in the peripheral portion of the distance portion, which causes an increase in image flow, blur, blur, distortion, and the like.

As described above, with reference to FIGS. 17 and 18, in the progressive multifocal lens of the second comparative example having a base curve smaller in curvature than the reference design of the present embodiment, the addition of a progressive multifocal plane When the refractive power distribution and the astigmatic difference distribution are made substantially equal to those of the reference design of the present embodiment, an area where the additional sphere power of the transmitted light is 0.50 diopter or less and the astigmatism is 0.50 diopter or less in the present embodiment. It can be seen that it becomes much narrower than the reference design. For this reason, the progressive multifocal lens of the second comparative example has a very narrow clear vision region in the distance portion, and has poor optical performance different from the reference design of the present embodiment.

FIG. 19 is a surface additional refractive power distribution diagram of a second progressive multifocal lens which is a progressive multifocal lens according to the present embodiment and has a base curve whose curvature is smaller than that of the reference design. In the second progressive multifocal lens according to this embodiment, similarly to the second comparative example, the outer diameter φ is 70 mm, the base curve BC is 2.00 diopters, and the distance power Df is -2.50 diopters. And the degree of addition Ad =
2.00 diopters and the refractive index of the lens ne =
1.50, the distance eye point E is located 2 mm above the lens geometric center OG, and the distance center OF is located 8 mm above the lens geometric center OG.

As can be seen from a comparison between FIG. 3 and FIG.
In the second progressive multifocal lens of the present embodiment, the distance center OF
The positive surface additional refractive power of 0.50 diopter or more with respect to the surface additional refractive power is added to the distance side portion. Further, in the second progressive multifocal lens of the present embodiment, the area of the region where the surface additional refracting power is 0.50 diopter or less in the distance portion is smaller than that of the reference design of the present embodiment.

FIG. 20 is an astigmatic difference distribution diagram of the second progressive multifocal lens according to this embodiment. As can be seen from a comparison between FIG. 4 and FIG. 20, in the second progressive power multifocal lens of the present embodiment, the area of the region where the astigmatic difference is 0.50 diopter or less in the distance portion is wider than in the case of the reference design. And especially wide below the distance side portion near the middle portion.

FIG. 21 is an additional spherical power distribution diagram of a transmitted light beam of the second progressive multifocal lens according to the present embodiment. As can be seen from a comparison between FIG. 17 and FIG. 21, in the second progressive multifocal lens of the present embodiment, the area where the additional spherical power is 0.50 diopter or less in the distance portion has a surface refraction of the progressive multifocal plane. The force distribution is much wider than in the case of the second comparative example in which the force distribution is almost equal to the reference design of the present embodiment, and the spherical power distribution from the intermediate portion to the near portion side is also improved. As a result, as can be seen from a comparison between FIG. 5 and FIG. 21, the second progressive power lens according to the present embodiment has an additional spherical power closer to the additional spherical power distribution of the progressive multifocal lens according to the reference design of the present embodiment. It is a distributed lens.

FIG. 22 is a diagram showing the astigmatism distribution in the transmitted light of the second progressive multifocal lens according to the present embodiment.
As can be seen from a comparison between FIG. 18 and FIG. 22, in the second progressive multifocal lens according to the present embodiment, the area where the astigmatism is 0.50 diopters or less in the distance portion is the astigmatism of the progressive multifocal plane. The difference distribution is much wider especially in the upper part of the lens than in the second comparative example in which the difference distribution is almost equal to the reference design of the present embodiment. As a result, as can be seen from a comparison between FIG. 6 and FIG. 22, the second progressive multifocal lens of the present embodiment has an astigmatism closer to the astigmatism distribution of the progressive multifocal lens according to the reference design of the present embodiment. It is a distributed lens.

As described above, referring to FIG. 21 and FIG. 22, this embodiment has a base curve with a smaller curvature than the reference design of the present embodiment, and corresponds to a manufacturing range in which the distance power is more negative. In the second progressive multifocal lens according to the present embodiment, a wide clear vision zone in which the additional spherical power is 0.50 diopter or less and the astigmatism is 0.50 diopter or less in the distance portion is secured. It can be close to the optical performance in wearing.

It is apparent that the present invention can be applied to progressive multifocal lenses of various specifications and materials without being limited to the above embodiments.

[0064]

As described above, according to the present invention, the lens is designed so that the basic specifications are substantially equal.
In a series of multifocal lenses having a plurality of base curves, the optical characteristics on wearing can be made almost equal for all the base curves, and the optical performance in the wearing state can be set well. A progressive multifocal lens can be realized. In addition, especially in the distance portion, it is possible to secure a wide clear viewing area in which astigmatism is small and image blur due to power deviation is small.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of area division of a progressive multifocal lens designed symmetrically.

FIG. 2 is a schematic diagram of a region division of an asymmetric progressive multifocal lens in which a near portion N is asymmetrically arranged in consideration of a near center ON being closer to a nose in a worn state of a lens.

FIG. 3 is a distribution diagram of a surface additional refractive power of a progressive multifocal lens serving as a reference design in the embodiment of the present invention.

FIG. 4 is an astigmatic distribution diagram of a progressive multifocal lens according to a reference design of the present embodiment.

FIG. 5 is a distribution diagram of an additional spherical power in transmitted light of a progressive multifocal lens according to the reference design of the present embodiment.

FIG. 6 is an astigmatism distribution diagram of a transmitted light of a progressive multifocal lens according to the reference design of the present embodiment.

FIG. 7 is a surface additional refractive power distribution diagram of a progressive multifocal lens as a first comparative example with respect to the reference design of the present embodiment.

FIG. 8 is an astigmatic distribution diagram of a progressive multifocal lens according to a first comparative example.

FIG. 9 is an additional spherical power distribution diagram of transmitted light of the progressive multifocal lens according to the first comparative example.

FIG. 10 is an astigmatism distribution diagram of a transmitted light beam of a progressive multifocal lens according to a first comparative example.

FIG. 11 is a surface additional refractive power distribution diagram of a first progressive multifocal lens which is a progressive multifocal lens according to the present embodiment and has a base curve with a larger curvature than the reference design.

FIG. 12 is an astigmatic distribution diagram of the first progressive multifocal lens according to the present embodiment.

FIG. 13 is an additional spherical power distribution diagram of transmitted light rays of the first progressive multifocal lens according to the present embodiment.

FIG. 14 is an astigmatism distribution diagram of a transmitted light beam of the first progressive multifocal lens according to the present embodiment.

FIG. 15 is a surface additional refractive power distribution diagram of a progressive multifocal lens as a second comparative example with respect to the reference design of the present embodiment.

FIG. 16 is an astigmatic difference distribution diagram of a progressive multifocal lens according to a second comparative example.

FIG. 17 is an additional sphere distribution diagram of transmitted light of the progressive multifocal lens according to the second comparative example.

FIG. 18 is an astigmatism distribution diagram of a transmitted light beam of a progressive multifocal lens according to a second comparative example.

FIG. 19 is a surface additional refractive power distribution diagram of a second progressive multifocal lens according to the present embodiment, which has a base curve whose curvature is smaller than that of the reference design.

FIG. 20 is an astigmatic distribution diagram of the second progressive multifocal lens according to the present embodiment.

FIG. 21 is an additional sphere distribution diagram of transmitted light rays of the second progressive multifocal lens according to the present embodiment.

FIG. 22 is an astigmatism distribution diagram of a transmitted light beam of the second progressive multifocal lens according to the present embodiment.

[Explanation of symbols]

 F Distance section N Near section P Middle section MM 'Main meridian curve OF Distance center E Distance eye point OG Geometric center ON Near distance center

Claims (4)

[Claims] At least one surface of a lens, along a principal meridian curve dividing a refractive surface of the lens into a nose region and an ear region, a distance vision correction region corresponding to a distant view, and a near vision correction region corresponding to a near view. A near vision correction region to be provided, and a progressive region that continuously connects the refractive powers of the surfaces of the two regions between the far vision correction region and the near vision correction region, and a basic specification of the lens. there is designed to be substantially equal to a series of progressive multifocal lenses having a plurality of base curves, the first progressive power multifocal lens having a first base curve BC _L selected from said plurality of base curves the average surface refractive power of an arbitrary point on the progressive power multifocal surface in the far vision correction area and Pf _L, the area of a region that satisfies the Pf _L -BC _L ≦ 0.50 diopters and Sp _L, the first than one base curve BC _L A second base curve BC _S curvature is selected from substantially small and the plurality of base curves, a second progressive power multifocal having addition power and substantially the same addition power of the first progressive multifocal lens In the lens, the surface average refractive power at an arbitrary point on the progressive multifocal plane in the distance vision correction area is Pf _S, and Pf _S −BC
_The area of the region satisfying _S ≦ 0.50 diopter is Sp _S
A progressive multifocal lens characterized by satisfying the following condition: Sp _L > Sp _S (1) 2. A far vision correction area corresponding to a distant view and a near vision view corresponding to a near view at least on one surface of the lens along a principal meridian curve dividing the refractive surface of the lens into a nose side area and an ear side area. A near vision correction region to be provided, and a progressive region that continuously connects the refractive powers of the surfaces of the two regions between the far vision correction region and the near vision correction region, and a basic specification of the lens. there is designed to be substantially equal to a series of progressive multifocal lenses having a plurality of base curves, the first progressive power multifocal lens having a first base curve BC _L selected from said plurality of base curves the area of the region surface astigmatism in the far vision correction area is not more than 0.50 diopters and Sa _L, curvature than said first base curve BC _L from substantially small and the plurality of base curves Choice The a second base curve BC _S, the first progressive in the second progressive multifocal lens having addition power and substantially the same addition power of the multifocal lens, the surface astigmatism in the far vision correction area when is the area of the region is less than 0.50 diopters was Sa _S, progressive multifocal lens that satisfies the conditions of _{Sa L <Sa S (2)} . 3. A distance vision correction area corresponding to a distant view and a near vision view at least on one side of the lens along a principal meridian curve dividing the refractive surface of the lens into a nose side area and an ear side area. A near vision correction region to be provided, and a progressive region that continuously connects the refractive powers of the surfaces of the two regions between the far vision correction region and the near vision correction region, and a basic specification of the lens. there is designed to be substantially equal to a series of progressive multifocal lenses having a plurality of base curves, the first progressive power multifocal lens having a first base curve BC _L selected from said plurality of base curves the average surface refractive power of an arbitrary point on the progressive power multifocal surface in the far vision correction area and Pf _L, and the Pf _L -BC _L ≦ 0.50 area of a region that satisfies the diopter and Sp _L, the far Surface correction in the field of vision correction Astigmatism is the area of the region is less than 0.50 diopters and Sa _L, have a second base curve BC _S which curvature than said first base curve BC _L is selected from substantially small and the plurality of base curves In the second progressive multifocal lens having an addition substantially equal to the addition of the first progressive multifocal lens, the surface average refractive power of an arbitrary point on the progressive multifocal plane in the distance vision correction area It was used as a Pf _S, Pf _S -BC
_The area of the region satisfying _S ≦ 0.50 diopter is Sp _S
And the plane astigmatism in the distance vision correction area is 0.5
0 when the area of the region is diopter or less was _{Sa S, Sp L> Sp S} (1) Sa L < progressive multifocal lens that satisfies the conditions of Sa _S (2). 4. A region located above the geometric center OG of the progressive multifocal lens, the first progressive multifocal lens surface astigmatism having a first base curve BC _L is 0.50 diopters Hitoshimen an arbitrary point on the astigmatic difference curves and M _L, the horizontal distance from the principal meridional curve to said arbitrary point M _L is x (m
the geometric center vertical height from OG to said arbitrary point M _L when the m) and h _L, the second progressive multifocal lens surface astigmatism having a second base curve BC _S is 0 any point on Hitoshimen astigmatic curves is .50 diopters and M _S, the horizontal distance from the principal meridional curve to said arbitrary point M _S is x (m
In a region satisfying 15 ≦ | x | where h _S is a vertical height from the geometric center OG to the arbitrary point M _{S in} the case of m), h _L > h _S (3). The condition is always satisfied.
The progressive multifocal lens according to any one of the above items.