JP2006350381A - Both-sided aspherical varifocal refractive lens and method of designing in - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bi-aspherical type progressive-power lens which provides an excellent visual acuity correction for prescription values and a wide effective visual field with less distortion in wearing, by reducing a magnification difference of an image between a distance portion and a near portion of a lens, and further to obtain the bi-aspherical type progressive-power lens capable of decreasing the working time and cost. <P>SOLUTION: A progressive action of a progressive-power lens is divided in the vertical direction and the horizontal direction of the lens and then an optimal sharing ratio between the front and rear two surfaces of the object side and the eyeball side is set in each direction to configure one bi-aspherical type progressive-power lens. Further, machining of only the surface of an eyeball side as a bilaterally asymmetrical curved surface coping with a convergence action of an eye in near vision after receiving an order is made possible by using "bilaterally symmetrical semi-finished product" as an object side surface of the progressive refractive power lens. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention is, for example, a lens used as a progressive-power lens for presbyopia for glasses,
The progressive power action is divided and divided into a first refractive surface that is an object side surface and a second refractive surface that is an eyeball side surface, and the first surface and the second surface are divided. In addition, the present invention relates to a double-sided aspherical progressive-power lens and a design method thereof, which are configured to give a distance power (Df) and an addition power (ADD) based on a prescription value.

  Progressive-power lenses are widely used because they are presbyopic eyeglass lenses that are not easily perceived as presbyopia in appearance, and that they can be clearly visible continuously from long to short distances. Yes. However, multiple fields of view, such as a field of view for viewing a distance, a field of view for viewing a near distance, and a field of view for viewing an intermediate distance between them, are arranged without a boundary line in a limited lens area. Therefore, the width of each field of view is not always sufficient. Further, it is widely known that there are defects inherent to the progressive-power lens, such as a region in which the image is distorted or shaken mainly in the lateral visual field.

  Various proposals have been made for a long time with the aim of improving the disadvantages inherent to these progressive-power lenses, but the surface configuration of these conventional progressive-power lenses has a “progressive surface” on the object-side surface, and an eyeball. Most of the combinations had a “spherical surface” or “astigmatic surface” on the 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, for example, there are techniques described in Patent Documents 1 and 2 and the like, which are generally called back surface progression (or concave surface progression). The main purpose of the surface configuration in the back surface progression proposed in Patent Document 1 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 distance portion and the near portion are used. This is to reduce the magnification difference of the image of the part and to improve the distortion and shaking of the image.

  That is, Patent Document 1 adds (progress) a “progressive surface” that gives a predetermined addition power only to the eyeball-side surface by eliminating all “progressive action” by making the object-side surface spherical or rotationally symmetric aspherical. I am letting. Further, Patent Document 2 discloses that a “progressive surface” that gives a shortage of addition power to a “progressive surface” on the object side surface is less than a predetermined value and is used as a “spherical surface” or “astigmatic surface” on the back surface side. It is proposed to add (fuse).

  Further, although there are differences in purpose and grounds, as other prior arts of progressive power lenses having a configuration in which a “progressive action” is added to the eyeball side surface, for example, Patent Document 3, Patent Document 4, and Patent Document 5 Patent Document 6 and the like. Further, as in the case of Patent Document 2, there are Patent Document 7 and Patent Document 8, for example, as prior arts in which “progressive action” is given to both surfaces of the lens. The common point of these prior arts is that the required addition power is shared by the two surfaces on the object side and the eyeball side of the lens.

WO97 / 19382 gazette WO97 / 19383 publication Japanese Patent Publication No. 47-23943 JP-A-57-10112 Japanese Patent Laid-Open No. 10-206805 Japanese Patent Laid-Open No. 2000-21846 JP 2000-338452 A JP-A-6-118353

  The main purpose of the above-described prior art is to share a part or all of the addition power necessary for the progressive power lens from the object side surface of the lens to the eyeball side surface, so that the distance portion and the near purpose in the lens are used. It is intended to reduce the magnification difference of the part and improve the distortion and shaking of the image due to the magnification difference. However, there is little clear description about the grounds for obtaining such improvement effects, and there is only a partial description in Patent Document 2 (hereinafter, sometimes referred to as the prior art 1). . That is, Patent Document 2 discloses a calculation formula for lens magnification (SM) shown in the following formulas (1) to (3), which is adopted as a basic evaluation parameter for lens design.

Here, the description of Patent Document 2 is cited.
“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. "

  Patent Document 2 calculates the difference in magnification between the distance portion and the near portion using these lens magnification (SM) formulas, and since the difference in magnification is small, image distortion and shaking are improved. It is going to be.

According to the research of the present inventor, the conventional technique 1 has a certain effect as compared with other prior arts. 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 prior art 1 include parameters that should be applied only to the vicinity of the center of the lens. This is also clear from the descriptions “the distance L from the apex of the lens on the eyeball side to the eyeball” and “the lens center thickness t”. In other words, in the example of Patent Document 2, 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. Therefore, there is a possibility that an error occurs due to this.

b. In the prior art 1, the lens magnification SM is calculated using five basic evaluation parameters obtained by adding “lens refractive index n” in addition to the above L, t, Po, and Pb. 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 understood by tilting the lens with the power actually back and forth. Therefore, it can be 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 greatly below the lens center. Therefore, the lens design of the prior art 1 has a possibility of generating an error due to the calculation of the lens magnification 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 an application example to an astigmatic lens. Since this concept does not exist, for example, in the near portion located greatly below the lens center, there may be a case where “the magnification in the vertical direction is different from that in the horizontal direction”, which may cause an error.

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, the “objective distance” is not considered in the prior art 1. For this reason, the possibility of the error resulting from the absence of such consideration cannot be denied.

e. In prior art 1, the influence of the prism action is not taken into account in the magnification calculation. For this reason, there is a possibility of an error due to the absence of such consideration.

As described above, the prior art 1 is not always satisfactory from the viewpoint of calculating the “magnification” more accurately.

  The present invention has been made to solve such a problem, and in consideration of the influence of the above-mentioned “angle between the line of sight and the lens surface” and “objective distance”, the distance portion and the near portion in the lens The objective is to provide a double-sided aspherical progressive-power lens that reduces the difference in image magnification, provides a good visual acuity correction for prescription values, and provides a wide effective field of view with little distortion during wearing, and a design method thereof. To do.

  In order to solve the above-described problems, the present invention has the following configuration.

(First configuration)
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,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DHf + DHn <DVf + DVn and DHn <DVn
Is satisfied, and the surface astigmatism components at F1 and N1 of the first refractive surface are canceled by the second refractive surface, and 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 distribution of astigmatism on the first refractive surface is symmetrical with respect to one meridian passing through the distance power measurement position F1, and the distribution of astigmatism on the second refractive surface is The arrangement of the near power measurement position N2 on the second refractive surface is asymmetrical with respect to a single meridian passing through the distance power measurement position F2 on the second refractive surface. A double-sided aspherical progressive-power lens, characterized in that it is centered on the side.
According to this configuration, by increasing the sharing ratio of the lateral progressive action on the eyeball side surface, the field of view spreads in the horizontal direction, and by increasing the sharing ratio of the vertical progressive action on the object side surface, It is possible to provide a progressive power lens that has a wide binocular visual field that is easy to move in the line of sight, has little astigmatism, and is distorted when worn and has little distortion.
(Second configuration)
In the double-sided aspherical progressive-power lens refractive power lens according to the first configuration,
The double-sided aspherical progressive-power lens is characterized in that the transmission astigmatism distribution in the near portion of the double-sided aspherical progressive-power lens is arranged so that the nose side is dense and the temple side is sparse. .
According to this configuration, in addition to the effect of the first configuration, transmission astigmatism from the near portion to the side is approximated by the left and right eyes, and better binocular vision is possible.
(Third configuration)
A design method of 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, ,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DHf + DHn <DVf + DVn and DHn <DVn
Is satisfied, and the surface astigmatism components at F1 and N1 of the first refractive surface are canceled by the second refractive surface, and 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 distribution of astigmatism on the first refractive surface is symmetrical with respect to one meridian passing through the distance power measurement position F1, and the distribution of astigmatism on the second refractive surface is The arrangement of the near power measurement position N2 on the second refractive surface is asymmetrical with respect to a single meridian passing through the distance power measurement position F2 on the second refractive surface. A method for designing a double-sided aspherical progressive-power lens, characterized in that the lens is centered on the side.
According to this configuration, by increasing the sharing ratio of the lateral progressive action on the eyeball side surface, the field of view spreads in the horizontal direction, and by increasing the sharing ratio of the vertical progressive action on the object side surface, It is possible to provide a design method capable of obtaining a progressive power lens that is easy to move in the line of sight, has a wide binocular field of view with little astigmatism, is distorted during wearing, and has little distortion.
(Fourth configuration)
In the design method of the double-sided aspherical progressive-power lens according to the third configuration,
The double-sided aspherical progressive-power lens is characterized in that the transmission astigmatism distribution in the near portion of the double-sided aspherical progressive-power lens is arranged so that the nose side is dense and the temple side is sparse. Design method.
According to this configuration, in addition to the effects of the third configuration, transmission astigmatism from the near portion to the side is approximated by the left and right eyes, and better binocular vision is possible.
(Fifth configuration)
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,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DHf + DHn <DVf + DVn and DHn <DVn
Is satisfied, and the surface astigmatism components at F1 and N1 of the first refractive surface are canceled by the second refractive surface, and 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 distribution of the average power of the first refractive surface is symmetrical with respect to one meridian passing through the distance power measurement position F1, and the distribution of the average power of the second refractive surface is the second power distribution. The arrangement of the near power measurement position N2 on the second refracting surface is asymmetrical with respect to the nose side with respect to a single meridian passing through the distance power measurement position F2 on the refractive surface. A double-sided aspherical progressive-power lens, characterized in that
According to this configuration, by increasing the sharing ratio of the lateral progressive action on the eyeball side surface, the field of view spreads in the horizontal direction, and by increasing the sharing ratio of the vertical progressive action on the object side surface, It is possible to provide a progressive power lens that is easy to move the line of sight, has a wide binocular field of view with an appropriate average power, and is less distorted, distorted, and blurred when worn.
(Sixth configuration)
In the double-sided aspherical progressive-power lens according to the fifth configuration,
A double-sided aspherical progressive-power lens having a double-sided aspherical progressive-power lens in which the transmission average power distribution in the near portion of the double-sided aspherical progressive-power lens is arranged so that the nose side is dense and the temple side is sparse.
According to this configuration, in addition to the effect of the fifth configuration, the transmission average power from the near portion to the side is approximated by the left and right eyes, and better binocular vision is possible.
(Seventh configuration)
A design method of 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, ,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DHf + DHn <DVf + DVn and DHn <DVn
Is satisfied, and the surface astigmatism components at F1 and N1 of the first refractive surface are canceled by the second refractive surface, and 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 distribution of the average power of the first refractive surface is symmetrical with respect to one meridian passing through the distance power measurement position F1, and the distribution of the average power of the second refractive surface is the second power distribution. The arrangement of the near power measurement position N2 on the second refracting surface is asymmetrical with respect to the nose side with respect to a single meridian passing through the distance power measurement position F2 on the refractive surface. A method for designing a double-sided aspherical progressive-power lens, characterized in that:
According to this configuration, by increasing the sharing ratio of the lateral progressive action on the eyeball side surface, the field of view spreads in the horizontal direction, and by increasing the sharing ratio of the vertical progressive action on the object side surface, It is possible to provide a design method capable of obtaining a progressive-power lens that can easily move the line of sight, has a wide binocular visual field with an appropriate average power, and is less distorted, distorted, and blurred during wearing.
(Eighth configuration)
In the design method of the double-sided aspherical progressive-power lens according to the seventh configuration,
A method for designing a double-sided aspherical progressive-power lens, characterized in that the transmission average power distribution in the near portion of the double-sided aspherical progressive-power lens is arranged so that the nose side is dense and the temple side is sparse .
According to this configuration, in addition to the effects of the seventh configuration, the transmission average power from the near portion to the side is approximated by the left and right eyes, and better binocular vision is possible.
(Ninth configuration)
A double-sided aspherical progressive-power lens having a progressive-power action divided and distributed on a first refractive surface that is an object-side surface and a second refractive surface that is an eyeball-side surface;
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn-DHn> ADD / 2
Satisfying the following relational expression, canceling out the surface astigmatism component at N1 of the first refractive surface with the second refractive surface, and combining the first and second refractive surfaces, A double-sided aspherical progressive-power lens, characterized in that it provides a near power (Dn) based on the value.
According to this configuration, in particular, in the near portion, by increasing the sharing ratio of the lateral progressive action on the eyeball side surface, the field of view spreads in the horizontal direction, and at the same time, the sharing ratio of the vertical progressive action on the object side surface. Therefore, it is possible to provide a progressive-power lens that is easy to move from near and far, and that is distorted when worn and has little distortion.
(Tenth configuration)
In the ninth configuration, the double-sided aspherical progressive-power lens according to this aspect,
In the first refractive surface, when the lateral surface refractive power and the vertical surface refractive power at the distance power measurement position F1 are DHf and DVf, respectively,
DHf + DHn <DVf + DVn, and DVn−DVf> ADD / 2, and
DHn-DHf <ADD / 2
And the astigmatism component at F1 and N1 of the first refractive surface is canceled by the second refractive surface, and the first and second refractive surfaces are combined. A double-sided aspherical progressive-power lens characterized in that it provides a distance power (Df) and an addition power (ADD) based on a prescription value.
According to this configuration, in addition to the effect of the ninth configuration, it is possible to provide a progressive power lens in which the distance portion and the entire lens surface are prevented from being shaken or distorted.
(Eleventh configuration)
In the double-sided aspherical progressive-power lens according to the ninth or tenth configuration,
The first refractive surface is symmetrical with respect to a meridian passing through the distance power measurement position F1, and the second refractive surface is a distance power measurement position F2 of the second refractive surface. And the arrangement of the near power measurement position N2 on the second refractive surface is inset to the nose side by a predetermined distance. Double-sided aspheric progressive power lens.
According to this configuration, in addition to the effects of the ninth or tenth configuration, a wider binocular visual field can be given, particularly when the line of sight is moved from the distance portion to the near portion.
(Twelfth configuration)
In the double-sided aspherical progressive-power lens according to any one of the ninth to eleventh aspects,
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-field power measurement position N2 on the second refractive surface is inset to the nose side by a predetermined distance. A double-sided aspherical progressive-power lens.
According to this configuration, in addition to the effects of any of the ninth to eleventh configurations, it is possible to prevent the surface of the object side surface from being twisted that causes image distortion. Further, when the line of sight is moved from the distance portion to the near portion, a wider binocular visual field can be provided.
(13th configuration)
In the double-sided aspherical progressive-power lens according to any one of Items 9 to 11,
On the first refracting surface, the horizontal cross section curve passing through the distance power measurement position F1 is not a perfect circle but has a predetermined refractive power change, and an arbitrary position on the horizontal cross section curve. The double-sided aspherical progressive-power lens according to claim 1, wherein a cross-sectional curve by a vertical cross section including a normal line is substantially the same as a meridian passing through the distance power measurement position F1.
According to this configuration, in addition to the effects of any one of the ninth to eleventh configurations, by adopting the above configuration, it is possible to reduce left and right side distortion and improve the side field of view.
(14th configuration)
In the double-sided aspherical progressive-power lens according to any one of Items 9 to 13,
The first and second refractive surfaces are combined to provide a distance power (Df) and an addition power (ADD) based on a prescription value, and a prism refractive power (Pf) is provided as necessary. Above, aspheric correction has been made on at least one of the items of astigmatism and power error caused by the fact that the line of sight and the lens surface in the wearing state cannot be orthogonal to each other, and the occurrence of image distortion in the peripheral visual field. A double-sided aspherical progressive-power lens characterized by that.
According to this configuration, in addition to the effects of any of the ninth to thirteenth configurations, the above-described aspherical correction suppresses transmission astigmatism, transmission power error, and image distortion in the peripheral visual field. A progressive power lens can be provided.
(15th configuration)
This is a design method of a double-sided aspherical progressive power lens having a progressive power action divided and distributed on a first refractive surface that is an object side surface and a second refractive surface that is an eyeball side surface. And
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn-DHn> ADD / 2
Satisfying the following relational expression, canceling out the surface astigmatism component at N1 of the first refractive surface with the second refractive surface, and combining the first and second refractive surfaces, A design method for a double-sided aspherical progressive-power lens, characterized in that the near power (Dn) is based on the value.
According to this configuration, in particular, in the near portion, by increasing the sharing ratio of the lateral progressive action on the eyeball side surface, the field of view spreads in the horizontal direction, and at the same time, the sharing ratio of the vertical progressive action on the object side surface. Therefore, it is possible to provide a design method capable of obtaining a progressive power lens that is easy to move in the distance of perspective and that is distorted during wearing and has little distortion.
(Sixteenth configuration)
In the design method of a double-sided aspherical progressive-power lens according to the fifteenth configuration,
In the first refractive surface, when the lateral surface refractive power and the vertical surface refractive power at the distance power measurement position F1 are DHf and DVf, respectively,
DHf + DHn <DVf + DVn, and DVn−DVf> ADD / 2, and
DHn-DHf <ADD / 2
And the astigmatism component at F1 and N1 of the first refractive surface is canceled by the second refractive surface, and the first and second refractive surfaces are combined. A design method for a double-sided aspherical progressive-power lens, characterized by providing a distance diopter (Df) and an add power (ADD) based on a prescription value.
According to this configuration, in addition to the effect of the fifteenth configuration, it is possible to provide a design method capable of obtaining a progressive power lens in which vibration and distortion are suppressed in the distance portion and the entire lens surface.
(17th configuration)
In the design method of a double-sided aspherical progressive-power lens according to fifteenth or sixteenth aspect,
The first refractive surface is symmetrical with respect to a meridian passing through the distance power measurement position F1, and the second refractive surface is a distance power measurement position F2 of the second refractive surface. And the arrangement of the near power measurement position N2 on the second refractive surface is inset to the nose side by a predetermined distance. To design a double-sided aspherical progressive-power lens.
According to this configuration, in addition to the effects of the fifteenth or sixteenth configuration, a wider binocular visual field can be given, particularly when the line of sight is moved from the distance portion to the near portion.
(18th configuration)
In the double-sided aspherical progressive-power lens designing method according to any one of the fifteenth to seventeenth aspects,
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-field power measurement position N2 on the second refractive surface is inset to the nose side by a predetermined distance. A double-sided aspherical progressive-power lens design method.
According to this configuration, in addition to the effects of any one of the fifteenth to seventeenth configurations, it is possible to prevent the surface on the object side from being twisted on the surface that causes image distortion. Further, when the line of sight is moved from the distance portion to the near portion, a wider binocular visual field can be provided.
(19th configuration)
In the design method of a double-sided aspherical progressive-power lens according to any one of 15th to 17th,
In the first refracting surface, the horizontal cross section curve passing through the distance power measurement position F1 is not a perfect circle but has a predetermined refractive power change, and at any position on the horizontal cross section curve A method for designing a double-sided aspherical progressive-power lens, characterized in that a cross-sectional curve by a vertical cross section including a normal line is substantially the same as a meridian passing through the distance power measurement position F1.
According to this configuration, in addition to the effects of any one of the fifteenth to seventeenth configurations, by adopting the above configuration, it is possible to reduce the lateral distortion and to improve the lateral field of view.
(20th configuration)
In the design method of a double-sided aspherical progressive-power lens according to any one of fifteenth to nineteenth,
The first and second refractive surfaces are combined to provide a distance power (Df) and an addition power (ADD) based on a prescription value, and a prism refractive power (Pf) is provided as necessary. Above, aspheric correction has been made on at least one of the items of astigmatism and power error caused by the fact that the line of sight and the lens surface in the wearing state cannot be orthogonal to each other, and the occurrence of image distortion in the peripheral visual field. A design method for a double-sided aspherical progressive-power lens, characterized in that
According to this configuration, in addition to the effects of any one of the fifteenth to nineteenth configurations, the above-described aspheric correction suppresses transmission astigmatism, transmission power error, image distortion in the peripheral visual field, and the like. A design method capable of obtaining a progressive-power lens can be provided.
(21st configuration)
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,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn-DVf> ADD / 2
Is satisfied, and the surface astigmatism components at F1 and N1 of the first refractive surface are canceled by the second refractive surface, and the first and second refractive surfaces are combined. To give the addition power (ADD) based on the prescription value,
And,
In the longitudinal section curve passing through F1, two horizontal lines located ± 4 mm in the longitudinal direction centering on the position giving 50% of the longitudinal section frequency change from F1 to the same height as N1, and the longitudinal line passing through F1 At an arbitrary position within a rectangle surrounded by two vertical lines located ± 15 mm horizontally from the direction straight line,
A double-sided aspherical progressive-power lens characterized in that the absolute value of the longitudinal differential value of the differential value of the surface longitudinal cross-sectional power at the first refractive surface is larger than the absolute value of the lateral differential value .
According to this configuration, in particular, in the central region where the progressive-power lens is frequently used, by increasing the ratio of the longitudinal progressive action on the object-side surface, the twist of the surface on the object-side surface is reduced, and the image Can be suppressed.
(Twenty-second configuration)
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,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn-DVf> ADD / 2
Is satisfied, and the surface astigmatism components at F1 and N1 of the first refractive surface are canceled by the second refractive surface, and the first and second refractive surfaces are combined. To give the addition power (ADD) based on the prescription value,
And,
In the longitudinal section curve passing through F1, two horizontal lines located ± 4 mm in the longitudinal direction centering on the position giving 50% of the longitudinal section frequency change from F1 to the same height as N1, and the longitudinal line passing through F1 At an arbitrary position within a rectangle surrounded by two vertical lines located ± 15 mm horizontally from the direction straight line,
The differential value of the amount of surface astigmatism on the first refractive surface is greater in the absolute value of the longitudinal differential value than in the absolute value of the lateral differential value,
And,
At any position within the rectangle,
The double-sided aspherical progressive-power lens according to claim 1, wherein the differential value of the surface average power on the first refractive surface has a larger absolute value of the longitudinal differential value than an absolute value of the lateral differential value.
According to this configuration, in particular, in the central region where the progressive-power lens is frequently used, by increasing the ratio of the longitudinal progressive action on the object-side surface, the twist of the surface on the object-side surface is reduced, and the image Can be suppressed. Further, by using the surface astigmatism amount and the surface average power as indices, it becomes easy to evaluate the optical performance of the lens.
(23rd configuration)
A design method of 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, ,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn-DVf> ADD / 2
Is satisfied, and the surface astigmatism components at F1 and N1 of the first refractive surface are canceled by the second refractive surface, and the first and second refractive surfaces are combined. To give the addition power (ADD) based on the prescription value,
And,
In the longitudinal section curve passing through F1, two horizontal lines located ± 4 mm in the longitudinal direction centering on the position giving 50% of the longitudinal section frequency change from F1 to the same height as N1, and the longitudinal line passing through F1 At an arbitrary position within a rectangle surrounded by two vertical lines located ± 15 mm horizontally from the direction straight line,
The differential value of the surface longitudinal direction cross-sectional power at the first refractive surface is such that the absolute value of the longitudinal differential value is larger than the absolute value of the lateral differential value, and the double-sided aspherical progressive power is characterized in that Lens design method.
According to this configuration, in particular, in the central region where the progressive-power lens is frequently used, by increasing the ratio of the longitudinal progressive action on the object-side surface, the twist of the surface on the object-side surface is reduced, and the image Can be suppressed.
(24th configuration)
A design method of 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, ,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn-DVf> ADD / 2
Is satisfied, and the surface astigmatism components at F1 and N1 of the first refractive surface are canceled by the second refractive surface, and the first and second refractive surfaces are combined. To give the addition power (ADD) based on the prescription value,
And,
In the longitudinal section curve passing through F1, two horizontal lines located ± 4 mm in the longitudinal direction centering on the position giving 50% of the longitudinal section frequency change from F1 to the same height as N1, and the longitudinal line passing through F1 The differential value of the amount of surface astigmatism on the first refracting surface is the lateral differential value at an arbitrary position within a rectangle surrounded by two vertical lines located ± 15 mm horizontally from the direction straight line. The absolute value of the longitudinal differential value is larger than the absolute value of
And,
At any position within the rectangle,
The differential value of the surface average power on the first refractive surface is such that the absolute value of the longitudinal differential value is larger than the absolute value of the lateral differential value. Design method.
According to this configuration, in particular, in the central region where the progressive-power lens is frequently used, by increasing the ratio of the longitudinal progressive action on the object-side surface, the twist of the surface on the object-side surface is reduced, and the image Can be suppressed. Further, by using the surface astigmatism amount and the surface average power as indices, it becomes easy to evaluate the optical performance of the lens.

According to the present invention, the progressive action of the progressive-power lens is divided into the longitudinal direction and the lateral direction of the lens, and the optimal ratio of the front and back surfaces on the object side and the eyeball side in each direction is determined. By defining a single-sided double aspherical progressive-power lens and increasing the ratio of the lateral progressive action on the back surface (eye surface), you can enjoy the advantage of expanding the field of view in the horizontal direction. By increasing the ratio of the longitudinal progressive action on the surface (object-side surface), it has become possible to suppress the disadvantage of increasing the eyeball rotation angle in the vertical direction.
Further, in the progressive-power lens, it was possible to give a wide effective field of view with little distortion during wearing by reducing the difference in magnification of the images in the distance portion and the near portion.
It is also possible to use a "symmetrical semi-finished product" as the object-side surface of the progressive-power lens, and after the order is received, only the eyeball-side surface can be processed as a left-right asymmetric curved surface corresponding to the eye's convergence effect in near vision. Thus, the processing time and cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the above description, the elucidation process of the present inventors will be described in the former part, and the double-sided aspherical progressive-power lens according to the present invention based on the elucidation result will be described in the latter part.

Here, FIG. 1 is an explanatory diagram of various surface refractive powers at various positions on the surface of the spectacle lens, FIG. 2 is an explanatory diagram of the positional relationship between the eyeball, the line of sight, and the lens, and FIGS. 3-1, 3-2 and 3 -3 and FIGS. 4-1, 4-2, and 4-3 are explanatory diagrams relating to the magnification Mγ of the prism. The difference between the plus lens and the minus lens, mainly viewed using the near portion at the bottom of the lens. FIG. 5A is an explanatory diagram 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. FIG. 5C is an explanatory view of the optical layout of the lens, and is a side view showing a cross section in the vertical direction; FIG. 5-3 is an explanatory view of the optical layout of the progressive-power lens, and an elevation view showing a cross section in the horizontal direction; 6 is an explanatory diagram showing the difference in the definition of “additional power”. . 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. In addition, the other symbols shown in FIG.
DVf: Surface refractive power at F of the longitudinal section curve through F DVn: Surface refractive power at N of the longitudinal section curve through N DHf: Surface refractive power at F of the transverse section curve through F DHn: It represents the surface power at N of the transverse cross-section curve through N. 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”.

[Clarification process]
The present inventors have improved by “corresponding the parameter to the near part”, which is the problem (a) described in the above conventional technique, and “considering the objective distance”, which is the problem (d). The calculation formula for the magnification corresponding to the near-use part was determined 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, which is a value 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 is considered that the mathematical formula used in the prior art 1 was “a special formula for far vision, which is an infinite objective distance”. Now, (1 ′) is the same as the mathematical formula of the above-mentioned prior art 1, but generally the objective distance for near vision is about 0.3 m to 0.4 m, so that the reciprocal Px is −2 The value is about .5 to -3.0. Therefore, the value of Mp increases because the value of the numerator increases in (2 ′), and the value of Ms decreases because the value of the denominator increases in (3 ′). That is, it can be seen that the influence of the shape factor Ms in near vision is less than the calculation result of the prior art 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 It can be seen that the image magnification is completely irrelevant.

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

From this point of view, the first calculation formulas in the above (1 ′) to (3 ′) are reviewed. There is a base curve (refractive power) Pb of the object side surface in the near 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 refractive power in the near portion: Pov = Po × (1 + Sin ² α × 4/3)
Lateral inner vertex power in the near portion: Poh = Po × (1 + Sin ² α × 1/3)
Longitudinal refractive power of object side surface in near portion: Pbv = Pb × (1 + Sin ² β × 4/3)
Cross-sectional refractive power of object side surface at 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 in order to simply explain that “the refractive power changes according to the direction of the line of sight”. However, in an actual optical design, it is desirable to obtain these values by strict ray tracing calculation. A non-limiting example of these calculation methods will be described.
First, the optical path along the line of sight is calculated using Snell's law, and L, t, and the distance from the object-side refractive surface to the object point are calculated. Next, along this optical path, by using the first basic form, the second basic form, Weingarten's formula, etc. in differential geometry, the refraction on the optical path on the object side refractive surface and the eyeball side refractive surface of the lens is performed. The refractive power can be calculated taking into account the influence of These formulas and calculation methods have been known for a very long time. For example, they are described in the 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 (a) to (d) in the conventional technique 1, are also considered. In addition to the near-use portion located greatly below the center of the lens, it is possible to perform a precise magnification calculation in all viewing directions.
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.

Thus, since “refractive power changes according to the direction of the line of sight”, it can be easily understood that all of 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 in the vertical direction and h is added in the horizontal direction, the above-described (1 ′) to (3 ′) are described with respect to the image magnification SM. Is 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 dealt with.

Finally, “impact by prism action”, which is the problem (e) of the above-described prior art 1, in calculating the magnification in actual near vision will be described.
The prism itself does not have a refracting 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 is 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.
It is. Also, the angular magnification γ due to refraction is
γ = Cos i / Cos r
It is represented by Here, since n ≧ 1, generally 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. The refraction angle r is
When n = 1 / Sin r, γ is the theoretical minimum value γ = 0
It becomes. At this time, i = π / 2
And r is equal to the critical angle of total reflection when a light ray comes out of 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 γ ′ = Cos i ′ / Cos r ′
It is represented by Since n ≧ 1, in general, r ′ ≧ i ′ and γ ′ ≧ 1. Here, the minimum value 1 of γ ′ is i ′ = r ′ = 0,
That is, in the case of normal incidence. The incident angle i ′ is n = 1 / Sin i ′.
Then, 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 are generally meniscus shaped with a convex object-side surface and a concave eyeball-side surface, 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 is Mγ ≧ 1 than that in FIG. 3A where Mγ = 1. It can be said that at least Mγ> 1. Similarly, as shown in FIG. 4-3, the near vision of the progressive addition lens in which the near portion has a negative refractive power has Mγ ≦ 1 rather than FIG. 4-1 where Mγ = 1. It is close to the shape of −2, and it can be said that at least Mγ <1. Therefore, 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 a result, the lens magnification SM in the prior art 1 was grasped only as the product of the power factor Mp and the shape factor Ms as described above, whereas in the present invention, the magnification Mγ of the prism is further multiplied. Thus, it is intended to obtain a correct lens magnification.

The magnification Mγ by the prism is referred to as a “prism factor” in comparison with Mp and Ms. The above equations (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.

  In a normal convex progressive-power 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 of the present invention, there is an advantage that the difference in magnification of the perspective image in the lateral direction is reduced by reducing the surface refractive power difference in the perspective of the “progressive surface” on the object side surface. It has been found that there are several problems in reducing the surface refractive power difference in the longitudinal direction.

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 refracting power, and Mγv> 1 when it has a positive refracting 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 look like a square is in the positive frequency and in the vertical direction, and in the negative frequency, it looks 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. By acting in an overlapping manner with the increase in the prism factor Mγv in the direction, the longitudinal magnification SMv is increased, resulting in a disadvantage that the magnification difference between the near and far images is increased.

  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.

The same applies to the fact that “the field of view expands”, which is generally regarded as an advantage of back surface progression (or concave surface progression) that is the eyeball side of the lens, as described below.
In general, astigmatism is present in the side portion of the “progressive surface”, and it is known that there is a limit to a good field of view in the horizontal direction. Therefore, if the “progressive surface” is arranged on the eyeball side surface, the “progressive surface” itself approaches the eye, and there is an advantage that a good field of view spreads in the horizontal direction. However, in the vertical direction, on the other hand, 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 drawback that the eyeball rotation angle increases.

  However, as described above, the present invention has a progressive power surface that satisfies the relational expression of DHf + DHn <DVf + DVn and DHn <DVn, or DVn-DVf> ADD / 2 and DHn-DHf <ADD / 2. In the horizontal direction, the back surface progression (or concave surface progression) is stronger than the conventional surface progression (or convex surface progression) feature, and in the vertical direction, the conventional surface progression (or concave surface progression) is stronger than the conventional surface progression (or concave surface progression) feature. (Or convex progression) 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.

In particular, as shown in Example 1 to be described later, if DVn−DVf = ADD and DHn−DHf = 0, it is equivalent to the conventional surface progression (or convex surface progression) in the vertical direction,
And,
In the horizontal direction, this is equivalent to back surface progression (or concave surface progression). Therefore, in this case, a very good result is obtained that the advantage in the horizontal direction can be obtained while the vertical defect is avoided.
Further, the above is effective in reducing the difference in image magnification between the distance portion and the near portion as described above and improving the distortion and shaking of the image, and can be said to be the effect 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. Here, the ratio of the longitudinal progressive action on the object side surface of the lens and the ratio of the lateral progressive action on the eyeball side surface can be set in a form exceeding at least 50%. For example, it is possible to set a sharing ratio in which all the progressive action in the vertical direction is given from the object side surface of the lens and all the progressive action in the horizontal direction is given from the eyeball side surface of the lens.

In the case of adopting this configuration, if one of the front and back surfaces of the lens is only one surface, it does not function as a normal progressive surface, and the addition power as the progressive surface cannot be specified. Then, an astigmatic surface or the like is synthesized on the surface according to the prescription.
On the other hand, although the various prior arts mentioned above all have a difference in the sharing ratio of the addition powers, first, on the front and back of the lens, first assign the “value” of the addition power required as a progressive surface to the front and back surfaces, respectively. Assuming a substantive progressive surface that gives the addition power, a composite surface with an astigmatism surface or the like is formed as necessary. That is, there is no configuration in which the progressive action is set separately in the vertical direction and the horizontal direction on the object side surface and the eyeball side surface of the lens.

  As described above, the lens according to the present invention is a double-sided aspherical progressive-power lens having a completely new configuration in which an aspherical surface having a progressive action different in both the vertical and horizontal directions is used on both sides.

[Double-sided aspherical progressive-power lens according to the present invention]
Hereinafter, a double-sided aspherical progressive refraction lens according to an embodiment of the present invention will be described.
(Lens design procedure)
Various procedures can be adopted as the general procedure of the optical design method of the double-sided aspherical progressive addition lens. For example, the following method can be used.
[1] Input information setting for lens design.
[2] Double-sided lens design as a convex progressive power lens.
[3] Conversion to a convex shape according to the present invention, and accompanying lens back surface correction.
[4] Correction of the back side of the lens due to transmission design and listing rule design.
Hereinafter, each procedure will be described in detail by breaking it down into smaller steps.

([1] Setting input information for lens design)
In lens design, input information for defining a predetermined progressive-power spectacle lens is set. Here, the input information will be described by roughly classifying into the following two types of item specific information and wearer specific information. (Factors other than optical design are omitted.)
[1] -1: Item specific information Data specific to a lens item. This is data relating to lens physical properties and shape factors such as a refractive index Ne of a material, a minimum center thickness CTmin, a minimum edge thickness ETmin, and a progressive surface design parameter.
[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 wear data (forward tilt, tilt angle, etc.), distance between vertices, layout data (distance PD, near-field CD, eye point position, etc.), and other data related to the eyeball etc. This is factor data regarding the frame.
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 on the wearer-specific information side.

([2] Double-sided lens design as a convex progressive-power lens)
In the first stage, a conventional convex progressive addition lens is designed with a convex surface and a concave surface.
[2] -1: Convex shape (convex progressive surface) design In order to realize the addition power ADD and progressive band length given as input information, the surface shape of the conventional convex progression according to the progressive surface design parameters as input information To design. Various conventional lens design methods can be used for the design in this step.

As a specific example of this lens design method, for example, there is a method of setting a “main meridian” corresponding to the backbone of the lens when the lens surface is first configured. This “main meridian” will eventually be the “main gaze”, which 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). preferable. However, it is not always necessary to perform the alignment of the near region corresponding to the eye convergence effect in the near vision by the alignment of the “main line of sight” 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. Furthermore, 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 method of designing the surface shape is adopted, 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 (the first refractive surface that is the object-side surface) is D1, and the surface refractive power of the rear surface of the lens (the 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 desirably a meniscus shape in which the object-side surface is convex and the eyeball-side surface is concave.
Here, D2 is assumed to be a positive value. Normally, the back surface of the lens is concave, and the surface refractive power has a negative value. However, in this specification, for simplicity of explanation, a positive value is used, and the transmission refractive power D is calculated by subtracting D2 from D1. To do.

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 required is a design of a “horizontal cross-sectional curve group” that corresponds to a rib when the lens surface is formed. 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 need to be equal to the “vertical surface power” along the “main meridian”. However, in this embodiment, the surface refractive powers in the vertical direction and the horizontal direction at these intersections are assumed to be equal.

All “horizontal cross-sectional curves” can be simple circular curves with surface power 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 of Japanese Patent Publication No. 49-3595. This sets a single “circular cross-sectional curve” in the shape of a circle 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 power distribution that decreases from the center to the side. In this way, the “main meridian” and countless “horizontal cross-sectional curve groups” arranged thereon constitute a lens surface like a spine and a rib, and the refractive surface is determined.

[2] -2: Concave surface shape (spherical surface or astigmatic surface) design Concave surface shape is designed to realize the distance dioptric power given as 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 known design techniques.

([3] Conversion to the convex shape of the present invention and accompanying lens back surface correction)
According to the distance power or addition power ADD given as input information, the conventional convex progressive addition lens is changed to the shape of the lens of the present invention.
[3] -1: Convex shape (invention of the present invention) design The conventional convex progressive surface is changed to the convex shape of the present invention in accordance with the distance power or addition power ADD given as input information. At this time, after dividing into the vertical direction and the horizontal direction of the lens in advance, a preferred ratio of the front and back two surfaces is set for each direction. That is, on the surface of the first convex progressive lens (the first refractive surface that is the object-side surface), the horizontal surface refractive power is DHf and the vertical surface refractive power at the distance power measurement position F1. Is DVf, and the near surface power measurement position N1 has a horizontal surface power DHn and a vertical surface power 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.
In this embodiment, both are set to satisfy.

  At this time, it is preferable to convert the average surface refractive power of the entire convex surface into the convex shape of the present invention without changing it. Specifically, 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, the lens preferably has a meniscus shape in which the object-side surface is convex and the eyeball-side surface is concave.

[3] -2: Concave 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 (the first refractive surface that is the object-side surface) added in the process [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. This deformation is similar to so-called “bending” in which the lens itself is bent, but it is not a uniform deformation over the entire surface of the lens but a surface that satisfies the relational expression described in [3] -1.

  Depending on the prescription and specifications of the lens, the invention may be completed at this step. However, it is preferable to treat the correction as a first-order approximate correction, and to add the following back surface correction step [4].

([4] Lens backside correction for transmission design, listing rule design, etc.)
In order to realize the optical function imposed on the lens as input information in a situation where the wearer actually wears the lens, the back surface correction is further performed on the lens according to the present invention obtained in [3]. It is preferable to add.
[4] -1: Concave surface shape design by transmissive design (present invention) The transmissive 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 generation of astigmatism and the change in power caused by the fact that the lens surface cannot be orthogonal.

More specifically, as described above, the surface correction (curve correction) is performed to grasp the difference from the original optical performance that is the target by strict ray tracing calculation according to the direction of the line of sight and 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, on the contrary, it is relatively easy to obtain “an optical performance of an arbitrarily set lens shape”. Accordingly, first, the surface of the first approximation is provisionally 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 approximation surface, and then the lens shape is changed. It is possible to gradually change and return to the evaluation step, and repeat 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 design for the design corresponding to the listing rule (the invention of the present application) The three-dimensional rotational movement of the eyeball when we look around is based on a rule called “listing rule” As is known, when the prescription power of the lens has an astigmatism 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 in peripheral vision May not match. As described above, the lens according to the present invention has the “correcting action” for removing or reducing the generation of astigmatism and the change in the power due to the astigmatic axis directions of the lens and the eye in peripheral vision not matching. It can be added to the curved surface of the surface having the astigmatism correcting action.

  Specifically, in order to add the “correction action” to the curved surface of the lens according to the present invention, as in the “optimization” method used in [4] -1, exact ray tracing calculation according to the direction of the line of sight Thus, the difference from the target original optical performance is grasped, and surface correction is performed to cancel the difference. By repeating this operation, the difference can be minimized and an optimal solution can be obtained.

[4] -3: Concave shape (invention of the present application) design for near-centering corresponding design In the present embodiment, in the present embodiment, the progressive-power spectacle lens of FIGS. As shown in the explanatory diagram of the optical layout, a design method is adopted in which the main meridian (M) is displaced to the nose side from the distance power measurement position (F) to the near power measurement position (N). This design method is a method that considers eye convergence, and the amount of displacement of the main meridian to the nose side based on the convergence action is set based on the following equation.
Displacement (H) ≒ A × D + B
Here, H is the displacement to the nasal side relative to the distance power measurement position (F) on the main meridian (M), D is the additional refractive power (add power ADD), A is a proportional constant, B is a constant ( (Including 0).

Here, the specific value of the amount of displacement differs depending on the prescription and addition power of the lens and can be arbitrarily set. For example, the following method can be adopted.
In Fig. 5-1, assuming a coordinate system with the point F as the origin, the H coordinate axis (horizontal displacement) on the right side, and the V coordinate axis (vertical direction) on the lower side, the near frequency measurement position (N) The H coordinate and V coordinate are H _MAX and V _MAX , respectively, and the addition power is D _MAX . Then, for example, the addition power D _MAX is specifically set to 3.00, the displacement is set to 2.5 mm (in this case, B = 0 is adopted), V is set to 12 mm, and the distance power measurement position ( This can be achieved by setting the displacement amount of each point on the meridian (M) at the near power measurement position (N) for each coordinate of V from F). (For example, refer to Japanese Examined Patent Publication No. 62-47284) Of course, the arrangement of the main meridian (main gaze) based on the eye's vergence is not limited to the above formula, and the adjustment of the amount of convergence and other factors are taken into account. You can also

  Further, in the lens processing method, the present invention adopts a double-sided aspherical surface configuration, but it is not always necessary to start processing on both sides after receiving an order. For example, it is possible to adopt a method in which a “semi-finished product (also referred to as semi-finished lens or abbreviated as semi-lens)” on the object side surface that meets the object of the present invention is prepared in advance. And after selecting an order, select the “semi-finished product on the object side surface” according to the specifications such as the prescription frequency and the above-mentioned custom-made (individual design), and processing and finishing only the eyeball side surface after receiving the order. Cost reduction and processing speed can be increased.

  As a specific example of this method, for example, in the above-mentioned [3] -1 convex shape design (the present invention) design, a method can be adopted in which the object side surface is prepared in advance as a symmetric “semi-finished product”. That is, here, the main meridian (= main line of sight) is a straight line, and the distribution of astigmatism on the refractive surface is symmetrical with respect to the main meridian, which is the main meridian considering eye convergence. Not. Therefore, since it is not necessary to prepare semi-lenses separately for the left eye and the right eye, processing and inventory management are facilitated. Then, after personal information such as interpupillary distance, near-distance objective distance, and addition power is input, the left and right asymmetric curved surface design (progression and near-field refraction is used). Since the astigmatism distribution on the surface is asymmetrical with respect to the main meridian, the near portion corresponding to the personal information can be aligned.

Hereinafter, an embodiment of a double-sided aspherical progressive refraction lens designed by the above design method will be described with reference to the drawings.
FIG. 7 shows the “surface refractive power” and “strict magnification calculation result 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. 8 is a table collectively shown in Table 1 and Table 1-2, and FIG. Table 2-1 and Table 2-2 collectively showing “magnification result of magnification”, FIG. 9 shows “surface refractive power” and “surface refractive power” of conventional techniques A, B, and C corresponding to Example 3 and the frequency thereof. Table 3-1 and Table 3-2 collectively showing "strict magnification calculation results for specific gaze direction", FIG. 10 is a graph 1-1 showing surface refractive power distribution of Example 1 and Example 2
FIG. 11 is a graph showing the surface refractive power distribution of Example 3, FIG. 11 is a graph showing the surface refractive power distribution of Example 3, and FIG. FIG. 13 shows the surface refractive power distribution of Example 7, which is a graph showing the surface refractive power distribution 6-1, 4-2, 5-1, 5-2, 6-1 and 6-2. Graphs 7-1 and 7-2 and FIG. 14 are graphs A-1, A-2, B-1, B-2, and C- showing surface refractive power distributions of the related art examples A, B, and C, respectively. 1 is a graph showing C-2.

FIG. 15 shows the result obtained by carrying out a strict magnification calculation for 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. Graph 1-3-3-Msv is shown, and FIG. 16 shows the magnification distribution when the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight. FIG. 17 shows a graph 1-3-3-Msh representing the result obtained by performing various magnification calculations. FIG. 17 shows the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the frequency as the main line of sight. FIG. 18 shows a graph 1-3-3-Mpv showing the result obtained by performing a strict magnification calculation of the magnification distribution when viewed along the line. FIG. 18 shows three types of conventional examples A, A corresponding to Example 1 and its frequency. The magnification distribution when the B and C lenses were viewed along the main line of sight was obtained by performing a strict magnification calculation. FIG. 19 shows a graph 1-3-Mph representing the results. FIG. 19 shows a magnification distribution when the lenses of Example 1 and three types of conventional examples A, B, and C corresponding to the frequency are viewed along the main line of sight. FIG. 20 shows a graph 1-3-3-Mγv representing the result obtained by performing a strict magnification calculation of FIG. 20, and FIG. 20 mainly focuses on the lenses of Example 1 and three conventional examples A, B, and C corresponding to the frequency. FIG. 21 shows a graph 1-3-Mγh showing the result obtained by performing a strict magnification calculation of the magnification distribution when viewed along the line of sight. FIG. 21 shows Example 1 and three types of conventional examples corresponding to the frequency. FIG. 22 shows a graph 1-3-3-SMv that represents a result obtained by performing a strict magnification calculation on the magnification distribution when the lenses A, B, and C are viewed along the main gazing line. Double of the three conventional lenses A, B, and C corresponding to the power when viewed along the main line of sight Distribution shows a graph 1-3-SMh representing results obtained by performing the accurate magnification calculations.

FIG. 23 shows the result obtained by carrying out a strict magnification calculation of the magnification distribution when viewing the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the power along the main line of sight. FIG. 24 showing a graph 2-3-3-Msv represents 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. 25 shows a graph 2-3-3-Msh representing the result obtained by performing various magnification calculations. FIG. 25 shows the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency as the main line of sight. FIG. 26 shows a graph 2-3-3-Mpv showing the result obtained by performing a strict magnification calculation of the magnification distribution when viewed along the line. FIG. 26 shows Example 2 and three types of conventional examples A, A corresponding to the frequency. The magnification distribution when the B and C lenses were viewed along the main line of sight was obtained by performing a strict magnification calculation. FIG. 27 shows a graph 2-3-3-Mph representing the results. FIG. 27 shows a 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 gazing line. FIG. 28 shows a graph 2-3-3-Mγv showing the result obtained by performing a strict magnification calculation of FIG. 28. In FIG. 28, the lenses of Example 2 and three types of conventional examples A, B, and C corresponding to the frequency are mainly used. FIG. 29 shows a graph 2-3-3-Mγh that represents the result of performing a strict magnification calculation of the magnification distribution when viewed along the line of sight. FIG. 29 shows Example 2 and three types of conventional examples corresponding to the frequency. A, B, C
FIG. 30 shows a graph 2-3-3-SMv that represents a result obtained by performing a strict magnification calculation on a magnification distribution when viewing the lens of the lens along the main gazing line. FIG. 30 corresponds to Example 2 and the frequency thereof. Graph 2-3-3-SMh showing the result of performing a strict magnification calculation on the magnification distribution when viewing the lenses of three types of conventional examples A, B, and C along the main gazing line is shown.

FIG. 31 shows the result obtained by performing 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 frequency along the main line of sight. FIG. 32 showing a graph 3-3-Msv showing the strict 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. 33 shows a graph 3-3-Msh representing the result obtained by performing various magnification calculations. FIG. 33 shows the lenses of Example 3 and three types of conventional examples A, B, and C corresponding to the frequency as the main gaze line. FIG. 34 shows a graph 3-3-Mpv showing the result obtained by carrying out a strict magnification calculation of the magnification distribution when viewed along the line. FIG. 34 shows Example 3 and three types of conventional examples A, A corresponding to the frequency. The magnification distribution when the B and C lenses were viewed along the main line of sight was obtained by performing a strict magnification calculation. FIG. 35 shows a graph 3-3-Mph representing the results. FIG. 35 shows a 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 the result obtained by performing a strict magnification calculation of FIG. 36. In FIG. FIG. 37 shows a graph 3-3-Mγh that represents the result obtained by performing a strict magnification calculation of the magnification distribution when viewed along the line of sight. FIG. 37 shows Example 3 and three types of conventional examples corresponding to the frequency. FIG. 38 shows a graph 3-3-SMv representing the result obtained by performing a strict magnification calculation on the magnification distribution when the lenses A, B, and C are viewed along the main gazing line. Double of the three conventional lenses A, B, and C corresponding to the power when viewed along the main line of sight Distribution shows a graph 3-3-SMh representing results obtained by performing the 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 power of the lens of Example 1 corresponds to S0.00 Add3.00, and three types of prior art examples of the same power 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 at the distance power measurement position F1 on the object side surface DHf1: Horizontal surface power at the distance power measurement position F1 on the object side surface DVn1: Near power measurement position N1 on the object side surface Surface refractive power in the vertical direction at DHn1: Surface refractive power in the lateral direction at the near power measurement position N1 on the object side surface DVf2: Surface refractive power in the vertical direction at the distance power measurement position F2 on the eyeball side surface DHf2: Surface on the eyeball side Surface refractive power in the lateral direction at the distance power measurement position F2 of the lens DVn2: Surface refractive power in the vertical direction at the near power measurement position N2 on the eyeball side surface DHn2: Surface in the lateral direction at the near power measurement position N2 on the eyeball side surface Refractive power

  Graphs 1-1 and 1-2 in FIG. 10 are graphs representing the surface refractive power distribution along the main gazing line of the lens of Example 1, the horizontal axis represents the position (distance) of the lens, and the right side is the graph. The upper side and the left side of the lens indicate the lower side of the lens, and the vertical axis indicates the surface refractive power. Here, the graph 1-1 corresponds to the object side surface of the lens, and the graph 1-2 corresponds to the eyeball side surface of the lens. The solid line graph represents the surface refractive power distribution in the vertical direction along the main gaze line of the lens, and the dotted line graph represents the surface refractive power distribution in the horizontal direction along the main gaze line of Len.

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.
In addition, these graphs are graphs for explaining basic differences in the surface configuration, such as an aspheric surface for removing astigmatism in the peripheral portion, an astigmatism component addition for dealing with astigmatism power, etc. Elements are omitted. (The same applies to Examples 2 to 7 below.)

Furthermore, for comparison, graphs A-1 and 2 shown in FIG. 14 are graphs showing surface refractive power distributions along the main line of sight of the lenses of the three prior art lenses having the same power listed in Table 1-1. Graphs B-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 on the eyeball side surface CV1: Graph showing the surface refractive power distribution in the vertical direction along the main line of sight on the object side surface (displayed with 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 a dotted line)
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 three types of prior art examples according to the present invention were all compared 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 the 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.

The lenses of Example 1 and the three types of prior art examples all have a refractive index n = 1.699, a center thickness t = 3.0 mm, a geometric center GC, and no prism. Regarding the objective power (reciprocal of the 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 = + 15.0 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 the surface refractive power are both front and back. It can be compared under the same conditions regardless of the side.

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 the prior art examples of three types of lenses prepared for comparison. This corresponds to the graph 1-3SMv (vertical total magnification) in FIG. 21 and the graph 1-3SMh (horizontal total magnification) 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.
Longitudinal 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)

Looking at SMvfn and SMhfn in Table 1-2, that is, the longitudinal magnification difference (SMvn-SMvf) and the lateral magnification difference (SMhn-SMhf), the prior art example A is 0.1380, 0.1015, and B is While the values of 0.1360 and 0.0988 and C are 0.1342 and 0.0961, the value of Example 1 according to the present invention is suppressed to a low magnification difference of 0.1342 and 0.0954. Recognize. 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. Note that Patent Document 2 corresponding to the above-described prior art 1 does not consider the difference between the vertical direction and the horizontal direction 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. As can be readily seen by comparison, the magnification distributions of the images in the vertical and horizontal directions are clearly different. Moreover, 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).

The above 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, and similarly, 1-3SMh is obtained by multiplying the values of three elements, graph 1-3Msh, graph 1-3Mph, and graph 1-3Mγh. Here, when comparing the vertical direction and the horizontal direction of each element, 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 no difference in magnification in the vertical direction and the horizontal direction is seen in Patent Document 2 corresponding to the prior art 1 does not consider the prism factors Mγv and Mγh which are the main causes of the difference in magnification. 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).

Here, measurement results of astigmatism distribution and average power distribution of the lens according to Example 1 are shown. In addition, the measurement result was shown using the curve which connected the iso-level point of 0.25 diopter pitch.
All drawings disclosed in this specification are right-eye lenses, and the lens diameter is 50 mm.
FIG. 39 is a diagram showing the astigmatism distribution in the transmission state of the double-sided design lens, and FIG. 40 is a diagram showing the average power distribution as well.
FIG. 41 is a diagram showing the astigmatism distribution on the convex surface side (first surface) of the double-sided design lens, and FIG. 42 is a diagram showing the average power distribution as well. In particular, in the astigmatism distribution and the average power distribution, it is understood that the progressive zone has a shape that is almost linear. The reason for not being a perfect straight line is that an aspherical component is included.
FIG. 43 is a diagram showing the frequency distribution in the horizontal (horizontal) direction on the refractive surface on the convex surface side (first surface) of the double-sided design lens, and FIG. 44 shows the frequency distribution in the vertical (vertical) direction on the refractive surface. FIG.
FIG. 45 is a diagram showing the astigmatism distribution on the concave surface side of the double-sided design lens, and FIG. 46 is a diagram showing the average power distribution as well.
FIG. 47 is a diagram showing the frequency distribution in the horizontal (horizontal) direction on the refractive surface on the concave surface (second surface) of the double-sided design lens, and FIG. 48 shows the frequency distribution in the vertical (vertical) direction on the refractive surface. FIG.
For comparison, the measurement results of the astigmatism distribution and the average power distribution of the lens according to the related art are shown.
FIG. 49 is a diagram showing the astigmatism distribution on the convex surface side (first surface) of the lens according to the prior art, and FIG. 50 is a diagram showing the average power distribution as well.
FIG. 51 is a diagram showing the frequency distribution in the horizontal (horizontal) direction on the refractive surface on the convex surface side (first surface) of the lens according to the prior art, and FIG. 52 is also the vertical (vertical) direction on the refractive surface. It is a figure which shows frequency distribution.
In the case of a lens according to the prior art, the concave surface (second surface) is a spherical surface or an astigmatism surface, and a curve connecting equal levels of 0.25 diopter pitch cannot be drawn.

(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 lens power of Example 2 corresponds to S + 6.00 Add3.00, and three prior art examples of the same power are shown for comparison. Note that the description methods, terms, and the like of these prior arts are the same as those in the first embodiment. (The same applies to the description of the following embodiments.)

  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 A-2, graphs B-1 and B-2, and graphs C-1 and C-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 also has a deep curve of 10.50 diopters for the convenience of corresponding 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 vertical surface refractive power distribution 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 beginning with “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 | required by performing exact | strict magnification calculation of. The terms and the meanings of the symbols attached after “Graph 2-3” are the same as those in Example 1 except that the 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 for a specific line-of-sight direction for Example 2 according to the present invention and three types of conventional technology prepared for comparison. It corresponds to 2-3-3-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.

  When SMvfn and SMhfn in Table 2-2, that is, the longitudinal magnification difference (SMvn-SMvf) and the lateral magnification difference (SMhn-SMhf) are examined, the prior art example A is 0.2275, 0.1325, and B is While the values of 0.2277 and 0.1268 and C are 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 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.

Further, 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 in each example is significantly 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 used, there is no difference between the examples in the perspective 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 closer 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.

  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. Here, the graph 3-1 corresponds to the object side surface, and the graph 3-2 corresponds to the eyeball side surface.

  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. The surface refractive powers at F1, N1, F2, and N2 also correspond to those in Table 3-1, and the average surface refractive power of the object-side surface indicated by the one-dot chain line in the horizontal direction at the center is also shown in Table 3-1. For convenience, it is assumed that each has a shallow curve of 2.50 diopters.

In graphs 3-1 and 3-2 of FIG. 12, 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 is viewed along the main gazing line, and the above-described strict magnification calculation. It is a graph showing the result calculated | required by performing. 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).

  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 in Example 3 is not much different from that in 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, Example 3 is the conventional example. In particular, the “vertical magnification tends to be smaller than 1” is less in the lower part than the near-use portion (the eye rotation angle is around −20 ° or less), and as a result, the “vertical / horizontal magnification difference” is the smallest. The distortion and shaking of the image is 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 small 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 least, 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. A list 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 is shown in 4-2 to graph 7-1 and graph 7-2.

(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), 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.

(Modification 1)
Two types of double-sided aspherical progressive-power lenses according to Modification 1 will be described.

The first double-sided aspherical progressive-power lens according to Modification 1 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,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn−DVf> ADD / 2 is satisfied, and surface astigmatism components at F1 and N1 of the first refracting surface are canceled by the second refracting surface. With the refractive surface of 2 to give an add power (ADD) based on the prescription value,
And,
In the longitudinal section curve passing through F1, two horizontal lines located ± 4 mm in the longitudinal direction centering on the position giving 50% of the longitudinal section frequency change from F1 to the same height as N1, and the longitudinal line passing through F1 At an arbitrary position within a rectangle surrounded by two vertical lines located ± 15 mm horizontally from the direction straight line,
A double-sided aspherical progressive-power lens characterized in that the absolute value of the longitudinal differential value of the differential value of the surface longitudinal cross-sectional power at the first refractive surface is larger than the absolute value of the lateral differential value It is.

The second double-sided aspherical progressive-power lens according to Modification 1 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,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn−DVf> ADD / 2 is satisfied, and surface astigmatism components at F1 and N1 of the first refracting surface are canceled by the second refracting surface. With the refractive surface of 2 to give an add power (ADD) based on the prescription value,
And,
In the longitudinal section curve passing through F1, two horizontal lines located ± 4 mm in the longitudinal direction centering on the position giving 50% of the longitudinal section frequency change from F1 to the same height as N1, and the longitudinal line passing through F1 The differential value of the amount of surface astigmatism on the first refracting surface is the lateral differential value at an arbitrary position within a rectangle surrounded by two vertical lines located ± 15 mm horizontally from the direction straight line. The absolute value of the longitudinal differential value is larger than the absolute value of
And,
At any position within the rectangle,
In the double-sided aspherical progressive-power lens, the differential value of the surface average power at the first refractive surface is greater in the absolute value of the longitudinal differential value than in the lateral direction. .

In designing these lenses, first, a longitudinal section curve passing through F1 on the object side surface is determined. This cross-sectional curve can be determined by a technique possessed when determining the longitudinal power distribution of the main meridian in a conventional progressive-power lens. (For example, see the design technique of Japanese Patent No. 2549738 by the inventors of the present application)
Next, a rotation surface having this curve as a generating line is defined. The rotation axis in the rotation plane is a straight line perpendicular to the normal of the generatrix at the geometric center of the lens in the plane including the generatrix (in the cross section),
And,
When the radius of curvature in the longitudinal direction at F1 is R1, and the angle between the normal of the generatrix at F1 and the normal of the generatrix at the geometric center is Θ, the distance R defined by R = R1 * COSΘ is the distance from F1. Located away from the eyeball. By rotating the generatrix previously defined using this rotation axis, it is possible to define the object-side surface in which the longitudinal power and the lateral power in F1 are matched.

In the above description, the object-side surface of the lens is a rotating surface, but the present invention can also be implemented on a sweep surface using a similar bus. The sweep surface is a surface obtained by sweeping a bus line along a three-dimensional curve (hereinafter referred to as a sweep line).
FIG. 57 shows an example of a general sweep surface.
In FIG. 57, the vertical solid line passing through F1 is the meridian.
58 is a view of the meridian of FIG. 57 as viewed from the side of the lens. O1 indicates the center of curvature of the meridian at F1, and the length of the arrow from O1 to F1 indicates the radius of curvature of the meridian at F1. . The fact that the length of the arrow decreases from the top to the bottom indicates that the radius of curvature along the meridian changes progressively.
In FIG. 57, a horizontal broken line passing through F1 is a sweep line.
FIG. 59 is a view of the sweep line of FIG. 57 as viewed from above the lens, O1 indicates the center of curvature of the sweep line at F1, and the length of the arrow from O1 to F1 indicates the radius of curvature of the sweep line at F1. ing.
The three arrows having the same length indicate that the sweep line is a circle centered on O1.
60 to 62 show examples of various sweep lines.
FIG. 60 shows an example of a sweep line in which the radius of curvature decreases with distance from F1,
FIG. 61 shows an example of a sweep line in which the radius of curvature increases with distance from F1,
FIG. 62 shows an example of a sweep line in which the change in the radius of curvature differs depending on the direction away from F1.

The sweep surface including the rotating surface used in the first modification has the following characteristics among general sweep surfaces, and will be described with reference to FIGS. 53 to 55.
Here, FIG. 53 is a diagram showing a frequency distribution (first surface) in the longitudinal (vertical) direction on the object-side surface of the lens according to Modification 1, and FIG. 54 is an object side of the lens according to Modification 1. FIG. 55 is a diagram showing a surface astigmatism distribution on the surface, and FIG. 55 is a diagram showing a surface average power distribution on the object side surface of the lens according to Modification Example 1. FIG. In each figure, two longitudinal section curves passing through F1 are located at ± 4 mm in the longitudinal direction centering on a position that gives 50% of the longitudinal section frequency change from F1 to the same height as N1. A rectangle surrounded by a horizontal line and two vertical lines positioned ± 15 mm in the horizontal direction from the straight line in the vertical direction passing through F1 is shown using a broken line.
FIG. 56 is a graph showing the change in the frequency of the longitudinal section curve passing through F1. The vertical direction represents the distance, and the horizontal direction represents the percentage of the frequency change amount with respect to the frequency at F1 when the frequency change from F1 to the same height as the near-use frequency measurement point N1 is 100%. As shown in FIG. 56, the center position of the rectangle in the vertical direction has a position corresponding to 50% as the center of the rectangle.
This rectangular region is the region that most prominently represents the feature of the progressive action in the progressive-power lens.

  As is apparent from the drawings, the longitudinal power does not change with respect to the movement in the lateral direction on the sweep surface including the rotating surface used in the present invention. Therefore, when the contour lines of the longitudinal cross-sectional frequency distribution shown in FIG. 53 are viewed, the contour lines are horizontal lines. Further, on the rotating surface, the contour lines of the surface astigmatism distribution shown in FIG. 54 and the contour lines of the surface average power distribution shown in FIG. 55 are also horizontal lines in the rectangle, similar to the contour lines of the longitudinal section power distribution.

  The lens according to the first modification includes not only a strict sweep surface but also a lens to which a slight aspherical correction is added. Therefore, each distribution is not completely horizontal, but on the surface based on the sweep surface, the differential value of the longitudinal cross-sectional frequency is higher than the absolute value of the horizontal differential value at any position in the rectangle. It has the characteristic that the absolute value of the directional differential value is larger. On the surface based on the rotation surface, the differential value of the surface astigmatism amount and the differential value of the surface average power are different from the absolute value of the lateral differential value at any position in the rectangle. The absolute value of the value is larger.

In the following, the absolute value of each differential value at a position that gives 50% of the change in the longitudinal section frequency from F1 to the same height as N1 in the center of the rectangle on the rotation surface, that is, the longitudinal section curve passing through F1. Indicates the value.

The absolute value of the differential value of the longitudinal cross section power (unit: diopter / mm [refractive index: 1.699])
Horizontal direction: 0.0, vertical direction: 0.24

Absolute value of differential value of surface astigmatism (unit: diopter / mm [refractive index: 1.699])
Horizontal direction: 0.0, vertical direction: 0.23

Absolute value of differential value of surface average power (unit: diopter / mm [refractive index: 1.699])
Horizontal direction: 0.0, vertical direction: 0.12

In the above example, since the rotation surface is used for the sake of simplicity, the differential values in the horizontal direction are all zero. In addition, aspherical correction, which is a “correcting action” for removing or reducing astigmatism and power changes mainly due to the fact that the line of sight and the lens surface cannot be orthogonal, is performed on the object-side surface or eyeball. It is desirable to add to one or both of the side surfaces. However, when aspherical correction is applied, the lateral differential value also has a slight value. However, the feature that the absolute value of the vertical differential value is larger than the absolute value of the horizontal differential value is maintained.
In addition, aspherical correction, which is a “correcting action” for removing or reducing astigmatism and power changes mainly due to the fact that the line of sight and the lens surface cannot be orthogonal, is performed on the object-side surface or eyeball. It is desirable to add to one or both of the side surfaces.
In the first modification, the design value of the first embodiment of the present specification is used, and an aspherical element is removed therefrom.

Next, the eyeball side surface is designed. Since the eyeball side surface is generally a curved surface having a complicated shape, a spline curved surface is used. By changing the parameters of the curved surface so that the desired transmission aberration distribution, prescription power, progressive band length, and hitting can be realized while evaluating the transmission aberration distribution by ray tracing calculation with the initial shape as a spherical surface, the eyeball Define the side surface.
Thus, the object side surface and the eyeball side surface are designed.

(Modification 2)
A double-sided aspherical progressive-power lens according to Modification 2 will be described.

The double-sided aspherical progressive-power lens according to Modification 2 has a progressive power action that is divided and distributed between the first refractive surface that is the object-side surface and the second refractive surface that is the eye-side surface. A double-sided aspherical progressive addition lens equipped with,
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn−DHn> ADD / 2 is satisfied, the surface astigmatism component at N1 of the first refractive surface is canceled by the second refractive surface, and the first and second refractions are canceled out. Together with the surface, it is configured to give a near-use frequency (Dn) based on the prescription value.

Furthermore, the double-sided aspherical progressive-power lens according to Modification 2 described above has the above-described configuration,
In the first refractive surface, the horizontal surface power and the vertical surface power at the distance power measurement position F1 are DHf and DVf, respectively.
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DHf + DHn <DVf + DVn,
And,
DVn-DVf> ADD / 2,
And satisfying the relational expression of DHn−DHf <ADD / 2, and canceling out the surface astigmatism components at F1 and N1 of the first refractive surface by the second refractive surface, The distance power (Df) and the addition power (ADD) based on the prescription value are combined with the two refractive surfaces.

Furthermore, the double-sided aspherical progressive-power lens according to Modification 2 described above, in addition to one of the two configurations described above,
The first refractive surface is symmetrical with respect to one meridian passing through the distance power measurement position F1, and the second refractive surface is a distance power measurement position F2 of the second refractive surface. Asymmetrical with a single meridian passing through
And,
The arrangement of the near power measurement position N2 on the second refracting surface is centered on the nose side by a predetermined distance, and has a configuration corresponding to the eye convergence action in near vision.

Furthermore, the double-sided aspherical progressive-power lens according to Modification 2 described above, in addition to any of the above three configurations,
The first refracting surface is a rotating surface having a meridian passing through the distance power measurement position F1 as a generating line, and the second refracting surface is a distance power measurement of the second refracting surface. Asymmetrical with respect to one meridian passing through position F2,
And,
The arrangement of the near power measurement position N2 on the second refracting surface is centered on the nose side by a predetermined distance, and corresponds to the eye's convergence effect in near vision.

Furthermore, the double-sided aspherical progressive-power lens according to Modification 2 described above, in addition to any of the above four configurations,
In the first refractive surface, the horizontal cross-sectional curve passing through the distance power measurement position F1 has a predetermined refractive power change, not a perfect circle,
And,
A cross-sectional curve with a vertical cross section including a normal line at an arbitrary position on the horizontal cross-sectional curve is substantially the same as a meridian passing through the distance power measurement position F1.

Furthermore, the double-sided aspherical progressive-power lens according to Modification 2 described above, in addition to any of the above five configurations,
The first and second refractive surfaces are combined to provide a distance power (Df) and an addition power (ADD) based on a prescription value, and a prism refractive power (Pf) is provided as necessary. Above,
This configuration reduces any or all of astigmatism and power error caused by the fact that the line of sight and the lens surface in the wearing state cannot be orthogonal to each other, and image distortion in the peripheral visual field.
Note that a design method for providing prism refractive power (Pf) as necessary is known, for example, in Japanese Patent Laid-Open No. 2003-121801, and such a design method can be used in combination.

The double-sided aspherical progressive-power lens according to Modification 2 having the above-described configuration will be described with reference to the drawings.
FIG. 57 shows a first refractive surface that is the object-side surface of the double-sided aspherical progressive-power lens in Modification 2. In this description, the vertical cross-section curve (solid line) passing through the distance power measurement position F1 indicated by a white circle in FIG. 5 is referred to as a meridian. It is “the meridian passing through the distance power measurement position F1” described in the third to fifth configurations. Moreover, what is shown with a broken line is a horizontal sectional curve.

  58 is a view of the meridian shown by the solid line in FIG. 57 as viewed from the side of the lens. FIG. 58 has a section in which the radius of curvature gradually decreases from the upper side to the lower side of the lens, and shows that a so-called progressive surface power change is given. O1 represents the center point of curvature, and the alternate long and short dash line represents the rotation axis passing through O1.

  FIG. 59 is a view of the horizontal cross section curve shown by the dotted line in FIG. 57 as viewed from above the lens, and O1 represents the center of curvature of the horizontal cross section curve. That is, the horizontal cross section curve shown by the dotted line in FIG. 59 is an arc. Here, the first refractive surface depicted in FIG. 57 can be obtained by rotating the meridian shown in FIG. 58 around the rotation axis passing through O1.

  In addition, the horizontal sectional curve of the first refracting surface according to the second modification example is not limited to the form shown in FIG. 59 but can take the form shown in FIGS. 60 to 62, and will be described below. Here, FIG. 60 is a first modification of the horizontal sectional curve viewed from above the lens shown in FIG. 59, and FIG. 61 is a second modified horizontal sectional curve viewed from above the lens shown in FIG. FIG. 62 shows a third modification of the horizontal sectional curve viewed from above the lens shown in FIG.

FIG. 60 shows an example of a horizontal cross-sectional curve in which the radius of curvature decreases as the distance from F1 increases.
FIG. 61 shows an example of a horizontal cross-section curve in which the radius of curvature increases as the distance from F1 increases, as opposed to FIG.
FIG. 62 shows an example of a horizontal sectional curve in which the examples of FIGS. 60 and 61 coexist.
Further, when the forms shown in FIGS. 60 to 62 are taken, it is also possible to add an effect of canceling the influence of the change in refractive power due to the change in the radius of curvature of the horizontal cross-section curve at the second refractive surface. .
The purpose is to use the change in the shape magnification of the image seen through the lens, and the shape magnification along the horizontal cross-section curve can be controlled to be suitable for the wearer. In particular, by taking the form shown in FIG. 62, it is possible to control the shape magnification of the nose side and the ear side during wearing.

  In order to simplify the description, the forms shown in FIGS. 60 to 62 are only examples in which the radius of curvature monotonously decreases or increases as the distance from F1 increases. Various modifications are possible, such as there are sections that do not change, or combinations of their reverse changes.

(Modification 3)
Here, different from the above-described configuration, an example of a double-sided aspherical progressive-power lens having no sweep surface will be described with reference to the drawings.
63 and 64 are diagrams showing a surface astigmatism distribution and a surface average power distribution on the object-side surface (first surface) of the lens according to Modification 3 of the embodiment. The marking method of the drawing is the same as that for the surface astigmatism distribution and surface average power distribution of the lens shown in FIGS. 41 and 42 described above. Further, the lens surface has the horizontal surface power and the vertical surface power at the distance power measurement position F1 as DHf and DVf, respectively, and the horizontal surface power and the vertical direction at the near power measurement position N1. When the surface refractive power is DHn and DVn, the following characteristics are obtained: DHf = DVf = 4.87, DHn = 6.12, and DVn = 7.87. The lens is an upper flat lens having a distance portion power of 0.00 and an addition power (ADD) of +3.00. It is clear from DHf << DHn that the object side surface (first surface) of the lens is not a sweep surface. Further, the value of DVn−DHn = 7.87−6.12 = 1.75 is less than the addition power, but exceeds 50% of the addition power, and the effect of the present invention can be obtained.
As described above, the purpose of making DHn a curve deeper than DHf is that when an object-side surface (first surface) of the lens is used to produce a strong positive distance power, the lens-side surface (first surface) This is for preventing the entire lens from becoming a meniscus shape.
65 and 66 are diagrams showing a surface astigmatism distribution and a surface average power distribution on the eyeball side surface (second surface) of the lens according to Modification 3 of the embodiment described above. The marking method of the drawing is the same as that shown in FIGS. 45 and 46 showing the surface astigmatism distribution and the surface average power distribution of the lens.

As the definition of “predetermined addition power” in the present invention, as shown in FIG. 6, the difference in 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 above case, when the refractive power difference is measured by applying the lens meter opening to the distance power measurement position F2 and the near power measurement position N2 on the eyeball side surface, the lens meter opening is further When the difference between the refractive power measured at the distance power measurement position F2 on the 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 addition, there are cases where only the refractive power component in the horizontal direction is used as each refractive power,
Any of these definitions can be adopted.

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. FIG. 6 is a diagram illustrating an astigmatism distribution in a transmission state of a lens according to Example 1. 6 is a diagram illustrating an average power distribution in a transmission state of a lens according to Example 1. FIG. FIG. 6 is a diagram illustrating an astigmatism distribution on the refractive surface on the convex surface side of the lens according to Example 1; 6 is a diagram showing an average power distribution on a refractive surface on the convex surface side of the lens according to Example 1. FIG. 6 is a diagram showing a frequency distribution in a horizontal (horizontal) direction on a refractive surface on the convex surface side of the lens according to Example 1. FIG. 6 is a diagram showing a frequency distribution in a vertical (vertical) direction on a refractive surface on the convex surface side of the lens according to Example 1. FIG. 6 is a diagram showing an astigmatism distribution on a refractive surface on the concave surface side of the lens according to Example 1. FIG. 6 is a diagram showing an average power distribution on a refractive surface on the concave surface side of the lens according to Example 1. FIG. 6 is a diagram showing a frequency distribution in a horizontal (horizontal) direction on a refractive surface on the concave surface side of the lens according to Example 1. FIG. 6 is a diagram illustrating a frequency distribution in a vertical (vertical) direction on a concave refractive surface of a lens according to Example 1. FIG. It is a figure which shows the astigmatism distribution in the refractive surface of the convex surface side of the lens which concerns on a prior art. It is a figure which shows the average frequency distribution in the refractive surface of the convex surface side of the lens which concerns on a prior art. It is a figure which shows the frequency distribution of the horizontal (horizontal) direction in the refractive surface of the convex surface side of the lens which concerns on a prior art. It is a figure which shows the frequency distribution of the vertical (vertical) direction in the refractive surface of the convex surface side of the lens which concerns on a prior art. It is a figure which shows the frequency distribution of the vertical (vertical) direction in the object side surface of the lens which concerns on the modification 1 of embodiment. It is a figure which shows the surface astigmatism distribution in the object side surface of the lens which concerns on the modification 1 of embodiment. It is a figure which shows the surface average frequency distribution in the object side surface of the lens which concerns on the modification 1 of embodiment. It is a figure which shows the frequency change of the vertical (vertical) direction in the object side surface of the lens which concerns on the modification 1 of embodiment. It is a figure which shows the example of the general sweep surface of the lens which concerns on the modification 2 of embodiment. It is the figure which looked at the meridian shown with the continuous line in FIG. 57 from the lens side. It is the figure which looked at the sweep line shown with the dotted line in FIG. 57 from the lens upper direction. It is the 1st modification of the sweep line seen from the lens upper part shown in FIG. FIG. 60 is a second modification of the sweep line viewed from above the lens shown in FIG. 59. FIG. FIG. 60 is a third modification of the sweep line viewed from above the lens shown in FIG. 59. FIG. It is a figure which shows the surface astigmatism distribution in the object side surface of the lens which concerns on the modification 3 of embodiment. It is a figure which shows the surface average frequency distribution in the object side surface of the lens which concerns on the modification 3 of embodiment. It is a figure which shows the surface astigmatism distribution in the eyeball side surface of the lens which concerns on the modification 3 of embodiment. It is a figure which shows the surface average frequency distribution in the eyeball side surface of the lens which concerns on the modification 3 of embodiment.

Claims (12)

A double-sided aspherical progressive-power lens having a progressive-power action divided and distributed on a first refractive surface that is an object-side surface and a second refractive surface that is an eyeball-side surface;
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn-DHn> ADD / 2
Satisfying the following relational expression, canceling out the surface astigmatism component at N1 of the first refractive surface with the second refractive surface, and combining the first and second refractive surfaces, A double-sided aspherical progressive-power lens, characterized in that it provides a near power (Dn) based on the value. The double-sided aspherical progressive-power lens according to claim 1,
In the first refractive surface, when the lateral surface refractive power and the vertical surface refractive power at the distance power measurement position F1 are DHf and DVf, respectively,
DHf + DHn <DVf + DVn, and DVn−DVf> ADD / 2, and
DHn-DHf <ADD / 2
And the astigmatism component at F1 and N1 of the first refractive surface is canceled by the second refractive surface, and the first and second refractive surfaces are combined. A double-sided aspherical progressive-power lens characterized in that it provides a distance power (Df) and an addition power (ADD) based on a prescription value. The double-sided aspherical progressive-power lens according to claim 1 or 2,
The first refractive surface is symmetrical with respect to a meridian passing through the distance power measurement position F1, and the second refractive surface is a distance power measurement position F2 of the second refractive surface. And the arrangement of the near power measurement position N2 on the second refractive surface is inset to the nose side by a predetermined distance. Double-sided aspheric progressive power lens. In the double-sided aspherical progressive-power lens according to any one of claims 1 to 3,
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-field power measurement position N2 on the second refractive surface is inset to the nose side by a predetermined distance. A double-sided aspherical progressive-power lens. In the double-sided aspherical progressive-power lens according to any one of claims 1 to 3,
On the first refracting surface, the horizontal cross section curve passing through the distance power measurement position F1 is not a perfect circle but has a predetermined refractive power change, and an arbitrary position on the horizontal cross section curve. The double-sided aspherical progressive-power lens according to claim 1, wherein a cross-sectional curve by a vertical cross section including a normal line is substantially the same as a meridian passing through the distance power measurement position F1. In the double-sided aspherical progressive-power lens according to any one of claims 1 to 5,
The first and second refractive surfaces are combined to provide a distance power (Df) and an addition power (ADD) based on a prescription value, and a prism refractive power (Pf) is provided as necessary. Above, aspheric correction has been made on at least one of the items of astigmatism and power error caused by the fact that the line of sight and the lens surface in the wearing state cannot be orthogonal to each other, and the occurrence of image distortion in the peripheral visual field. A double-sided aspherical progressive-power lens characterized by that. This is a design method of a double-sided aspherical progressive power lens having a progressive power action divided and distributed on a first refractive surface that is an object side surface and a second refractive surface that is an eyeball side surface. And
In the first refracting surface, when the horizontal surface power and the vertical surface power at the near power measurement position N1 are DHn and DVn, respectively,
DVn-DHn> ADD / 2
Satisfying the following relational expression, canceling out the surface astigmatism component at N1 of the first refractive surface with the second refractive surface, and combining the first and second refractive surfaces, A design method for a double-sided aspherical progressive-power lens, characterized in that the near power (Dn) is based on the value. The method for designing a double-sided aspherical progressive-power lens according to claim 7,
In the first refractive surface, when the lateral surface refractive power and the vertical surface refractive power at the distance power measurement position F1 are DHf and DVf, respectively,
DHf + DHn <DVf + DVn, and DVn−DVf> ADD / 2, and
DHn-DHf <ADD / 2
And the astigmatism component at F1 and N1 of the first refractive surface is canceled by the second refractive surface, and the first and second refractive surfaces are combined. A design method for a double-sided aspherical progressive-power lens, characterized by providing a distance diopter (Df) and an add power (ADD) based on a prescription value. The method for designing a double-sided aspherical progressive-power lens according to claim 7 or 8,
The first refractive surface is symmetrical with respect to a meridian passing through the distance power measurement position F1, and the second refractive surface is a distance power measurement position F2 of the second refractive surface. And the arrangement of the near power measurement position N2 on the second refractive surface is inset to the nose side by a predetermined distance. To design a double-sided aspherical progressive-power lens. In the double-sided aspherical progressive-power lens design method according to any one of claims 7 to 9,
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-field power measurement position N2 on the second refractive surface is inset to the nose side by a predetermined distance. A double-sided aspherical progressive-power lens design method. In the design method of the double-sided aspherical progressive-power lens according to any one of claims 7 to 9,
In the first refracting surface, the horizontal cross section curve passing through the distance power measurement position F1 is not a perfect circle but has a predetermined refractive power change, and at any position on the horizontal cross section curve A method for designing a double-sided aspherical progressive-power lens, characterized in that a cross-sectional curve by a vertical cross section including a normal line is substantially the same as a meridian passing through the distance power measurement position F1. In the design method of the double-sided aspherical progressive-power lens according to any one of claims 7 to 11,
The first and second refractive surfaces are combined to provide a distance power (Df) and an addition power (ADD) based on a prescription value, and a prism refractive power (Pf) is provided as necessary. Above, aspheric correction has been made on at least one of the items of astigmatism and power error caused by the fact that the line of sight and the lens surface in the wearing state cannot be orthogonal to each other, and the occurrence of image distortion in the peripheral visual field. A design method for a double-sided aspherical progressive-power lens, characterized in that

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