JP2012145672A - Eyeglass lens and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eyeglass lens capable of suppressing image deformation when viewing the screen of a PC, and also capable of reducing the increase of thickness of the eyeglass lens.SOLUTION: The object-side surface of an eyeglass lens 10 includes: a first region 21 of which average surface refractive power along a vertical reference line Y is a first value D1; a second region 22 of which average surface refractive power is a second value D2; and a third region 23 of which average surface refractive power increases from the first value D1 to a third value D3 and decreases from the third value D3 to the second value D2 between the first region 21 and the second region 22. The first region 21 is included in a far-sight part 11, the second region 22 is included in a short-sight part 12, and the third region 23 includes an intermediate part 13. Accordingly, the eyeglass lens can be provided to suppress deformation of a screen of a PC and the like mostly viewed via the intermediate part 13 and have thin thickness.

Description

  The present invention relates to a spectacle lens and a method for manufacturing the same.

  Patent Document 1 describes providing a progressive power lens that can reduce image distortion and blur that inevitably occur in a progressive power lens, and can improve wearing comfort. Therefore, in Patent Document 1, a double-sided progressive lens in which both the outer surface and the inner surface are progressive surfaces is used, the surface addition of the outer surface is negative, and the average surface refractive power distribution of the outer surface and the inner surface is similar. Designing a progressive surface shape is described. In other words, the progressive surface of the progressive power lens has been formed on the outer surface in the old days, but it has been found that the optical performance is dramatically improved by forming the progressive surface on the inner surface side. In order to apply the theory of the inner surface progressive lens and further improve the optical performance, in Patent Document 1, a double-sided progressive lens in which a progressive refractive surface is formed on both the outer surface and the inner surface and an average surface refractive power of the outer surface are used. Is set to decrease continuously from the distance portion to the near portion. By making the change in the average surface refractive power of the outer surface of the double-sided progressive lens negative, that is, by making the surface addition power of the outer surface negative, the magnification difference in the near portion can be reduced and the distortion can be reduced.

Japanese Patent Application Laid-Open No. 2004-4436 (Summary, paragraph numbers 0010 and 0011)

  With the glasses using the double-sided progressive lens, the magnification difference between the distance portion and the near portion can be reduced. However, since the average surface refractive power of the outer surface is set to continuously decrease from the distance portion to the near portion, the lens tends to be thicker than the inner surface progressive lens and the outer surface progressive lens. For this reason, there is a need for a spectacle lens that reduces image distortion that inevitably occurs in a progressive-power lens, suppresses the thickness of the lens, and provides a good wearing feeling.

  In one embodiment of the present invention, the object-side surface includes a first region having a first average surface refractive power along a main gazing line (main meridian) or a vertical reference line, and a second average surface refractive power. The average surface power increases from the first value to the third value between the second region with the value of 1, and between the first region and the second region, and from the third value to the second value. And a third region that decreases in value. An image obtained through a spectacle lens tends to increase in magnification when the lens power increases, and decreases as the average surface refractive power of the object-side surface decreases. Therefore, in this spectacle lens, the change in the magnification of the spectacle lens can be locally controlled by changing the average surface refractive power in the third region between the first region and the second region. . Therefore, in applications where the field of view that is frequently used is specified to some extent, it is possible to reduce image fluctuations and distortions in the field of view, and to provide a spectacle lens with a small convex height and edge thickness, and a substantial thickness. it can.

  One such application is the operation of a personal computer (PC). In recent years, an increasing number of users (wearers) spend a lot of time operating PCs. When a wearer of a multifocal lens having a distance portion and a near portion looks at the screen of the PC, he / she can see the screen through an intermediate portion where the frequency gradually changes between the distance portion and the near portion. Many. Therefore, by setting the third region in the portion from the distance portion to the near portion, it is a multifocal lens for eyeglasses that is easy to see the screen of the PC, and a thin lens can be provided.

  That is, a typical spectacle lens according to the present invention mainly includes a distance portion used when viewing an object at a long distance, a near portion used mainly when viewing an object at a short distance, and a distance portion. And the intermediate portion gradually changing in frequency between the near portion and the near portion, the first region of the object side surface is at least a portion of the far portion, and the second region is at least the near portion And the third region is located between the first region and the second region, the average surface power increases from the first value to the third value, and from the third value to the second value. Decrease to a value of 2. As a result, even if there is a magnification difference between the image obtained through the first region included in the distance portion and the image obtained through the second region included in the near portion, the third difference between the images is obtained. The distortion of the image obtained through the region can be reduced.

  In this spectacle lens, the user-side surface (inner surface) is a progressive surface, but the user-side surface also faces each of the first, second, and third regions on the object side. A fourth region where the average surface power (absolute value of the average surface power) along the main gazing line (main meridian) or vertical reference line is the fourth value, and the average surface power is the fifth value. The average surface refractive power increases from the fourth value to the sixth value and decreases from the sixth value to the fifth value between the fifth region, the fourth region, and the fifth region. And a sixth region. When the sixth area includes the distance portion, when the sixth area increases from the fourth value to the sixth value, the fourth value changes from the fourth value to the sixth value. Reach.

In this spectacle lens, when the eye point (fitting point) of the spectacle lens extends up and down and a positive coordinate is placed above the eye point, the first region and the third region The boundary between the boundary point (hereinafter also referred to as the first point) Ya, the point where the average surface refractive power is the third value (hereinafter also referred to as the third point) Yc, and the third region and the second region The point (hereinafter also referred to as the second point) Yb satisfies the condition of the following expression (1). In the following formula, the unit is mm.
Ya>Yc> Yb (1)

  Although it depends on spectacles specifications, typically, at the point Yc (third point), the average surface refractive power (base curve) on the object side often has a maximum value (third value).

The lower the boundary point (first point) Ya, the easier it is to make the lens thinner. Therefore, the boundary point Ya preferably satisfies the condition of the following expression (2).
Ya ≦ 15 (2)

Further, in order to obtain glasses suitable for viewing a PC, the third point Yc is a position for viewing the vicinity of the upper end of the PC screen, and the second point Yb is a position for viewing the vicinity of the lower end of the PC screen. preferable. For this reason, it is preferable that the third point Yc satisfies the condition of the following expression (3), and the second point Yb satisfies the condition of the expression (4) below.
−5 ≦ Yc ≦ 10 (3)
−25 ≦ Yb ≦ −5 (4)

If the distance between the first point and the third point is too short, the base curve of the surface on the object side changes abruptly, which may cause unnatural distortion in the distance portion. Further, it is necessary to secure a certain distance between the third point and the second point in order to keep the PC screen in view. Therefore, the first point Ya, the third point Yc, and the second point Yb preferably satisfy the conditions of the following expressions (5) and (6).
Ya-Yc ≧ 4 (5)
Yc−Yb ≧ 10 (6)

In this spectacle lens, when the first value is D1, the second value is D2, and the third value is D3, the following equation (7) should be satisfied. preferable. The unit is a diopter.
MAX (D1, D2) + 1 ≦ D3 ≦ (n−1) /0.015 (7)

  n is the refractive index of the material. MAX (D1, D2) is a function that selects the larger one of D1 and D2.

  In order to obtain the magnification correction effect of the third region, it is desirable that the third value D3 is at least 1D larger than the first value D1 and the second value D2. On the other hand, if the third value D3 exceeds 44, the curvature of the object side surface becomes too large and various aberrations increase. In addition, it is impossible to secure a size for fitting into a spectacle frame as a spectacle lens. The first value D1 and the second value D2 may be the same or different.

  Another aspect of the present invention is spectacles having the spectacle lens and a spectacle frame on which the spectacle lens is mounted. The eyeglasses are thin and compact, and a stable image can be obtained in specific applications such as little image fluctuation when operating a PC.

  Yet another embodiment of the present invention is a method for manufacturing a spectacle lens. The manufacturing method includes: a first region having a first average surface refractive power along a main gaze line or a vertical reference line; a second region having a second average surface refractive power; An object comprising a third region between the region and the second region, wherein the average surface power increases from the first value to the third value and decreases from the third value to the second value To form a side surface.

  According to this manufacturing method, it is possible to obtain a thin spectacle lens with small distortion of an image viewed through the limited third region, not the entire spectacle lens.

  This manufacturing method is further used to form the object-side surface, and at the same time, or at the same time, mainly used for viewing long-distance objects, and mainly for viewing short-distance objects. Forming a user-side surface having a near-use portion and an intermediate portion whose power gradually changes between the distance-use portion and the near-use portion, and a first region of the object-side surface It is desirable to face at least part of the distance portion and the second area face at least part of the near portion.

  Yet another aspect of the present invention is an apparatus for designing a multifocal lens for spectacles including a distance portion and a near portion having different powers. The apparatus includes a first unit for setting a user-side surface including a distance portion and a near portion, and a first unit whose average surface refractive power along a main gaze line or a vertical reference line is a first value. The average surface power increases from the first value to the third value in the region, the second region where the average surface power is the second value, and between the first region and the second region. And a second unit for setting an object-side surface including a third region that decreases from the third value to the second value. The second unit sets the object-side surface such that the first region faces at least a part of the distance portion and the second region faces at least a portion of the near portion. The apparatus may further include a unit for simulating a state viewed through a multifocal lens for spectacles including an object side surface and a user side surface.

The perspective view which shows an example of spectacles. 2A is a plan view schematically showing one lens of a multifocal lens for spectacles, and FIG. 2B is a cross-sectional view thereof. The figure which shows the surface refractive power of the lens for spectacles of the Example of this invention. The figure which shows the surface refractive power distribution and aberration distribution of the lens for spectacles of an Example. 5A is a diagram showing the surface refractive power of the spectacle lens of the example, FIG. 5B is a diagram showing the surface refractive power of the spectacle lens of Comparative Example 1, and FIG. The surface refractive power of the lens for eyeglasses of FIG. The figure which shows collectively the design data of the spectacles lens of an Example, and the spectacles lens of Comparative Examples 1-2. The figure which shows the magnification difference of the lens for spectacles of an Example, and the lens for spectacles of Comparative Examples 1-2. The figure which shows the convex surface height of the lens for spectacles of an Example, and the lens for spectacles of the comparative example 2. FIG. The flowchart for demonstrating an example of the manufacturing method of the lens for spectacles. The figure which shows schematic structure of an example of the design apparatus of the lens for spectacles.

  FIG. 1 is a perspective view showing an example of eyeglasses. FIG. 2A schematically shows one lens of the multifocal lens for spectacles of the embodiment of the present invention in a plan view. FIG. 2B schematically shows one of the multifocal lenses for spectacles according to the embodiment of the present invention in a cross-sectional view.

  In this example, as viewed from the user side (user side, wearer side, eyeball side), the left side is left and the right side is right. Hereinafter, a configuration common to the left-eye lens 10L and the right-eye lens 10R will be described as the spectacle lens 10. The left-eye lens 10L and the right-eye lens 10R are basically symmetrical structures.

  The spectacles 1 includes a pair of left and right spectacle lenses 10L and 10R for left eye and right eye, and a spectacle frame 20 on which the lenses 10L and 10R are respectively mounted. The spectacle lenses 10 (10L and 10R) are spectacle multifocal lenses, and more specifically, progressive multifocal lenses (progressive power lenses). The basic shape of the spectacle lens 10 is a meniscus lens convex on the object side. The eyeglass lens 10 includes an object-side surface (convex surface, also referred to as an outer surface) 19A and an eyeball-side (user side) surface (a concave surface, also referred to as an inner surface) 19B.

  The spectacle lens 10 is an inner surface progressive lens, and the inner surface 19B includes a distance portion 11 which is a visual field portion for viewing an object at a long distance upward, and has a power (refractive power) different from that of the distance portion 11 below. It includes a near portion 12 which is a visual field portion for viewing an object at a short distance. Furthermore, the inner surface 19B of the spectacle lens 10 includes an intermediate portion (progressive portion) 13 that connects the distance portion 11 and the near portion 12 so that the refractive power continuously changes.

  In the conventional inner surface progressive lens and outer surface progressive lens, the magnification of the image viewed through the near portion is larger than the magnification of the image viewed through the distance portion, so that the near portion side of the image viewed through the intermediate portion is stretched in the horizontal direction. . For this reason, the square image looks like a trapezoid whose bottom is longer than the top. What is viewed over a long period of time with glasses on, such as a PC screen, is often an image obtained through the intermediate section 13. At this time, the image obtained through the intermediate portion looks like a trapezoid, which gives an impression that the image is distorted, and the wearing feeling of the glasses decreases.

That is, the magnification M of the spectacle lens is approximately expressed by the following equation.
M = Ms × Mp (8)

Here, Ms is called a shape factor, and Mp is called a power factor. The refractive index of the lens substrate is n, the base curve (surface refractive power) of the object side surface of the lens is D (diopter, diopter), and the distance from the vertex (inner vertex) of the lens eyeball side surface to the eyeball is L Mp and Ms are expressed as follows, where P (frequency S) is the refractive power of the inner vertex (inner vertex refractive power) and t is the thickness of the lens center.
Ms = 1 / (1-D × t / n) (9)
Mp = 1 / (1-L × P) (10)

  In calculating the equations (9) and (10), diopter (D) is used for the base curve D and the inner vertex power P, and meters (m) are used for the thickness t and the distance L.

Therefore, Formula (8) becomes as follows.
M = {1 / (1-D × t / n)} × {1 / (1-L × P)} (8)

  As can be seen from this equation (8), as the refractive power P increases, the magnification M also increases, and the magnification M of the image increases in the near portion 12 to which the addition is added.

  In eyeglasses using a double-sided progressive lens that reduces the magnification difference between the distance portion 11 and the near portion 12, the intermediate portion is obtained by making the base curve of the near portion 12 smaller than the base curve of the distance portion 11. The image obtained through 13 looks to be trapezoidal or the magnification of the image is changed. However, in order to maintain the state of the meniscus lens suitable for the spectacle lens as the cross-sectional shape of the near portion 12, it is necessary to relatively increase the base curve of the distance portion 11, resulting in the convex surface of the spectacle lens. The height (sag value) is large, and the lens becomes thicker than the inner surface progressive lens and the outer surface progressive lens. For this reason, in order to further improve the wearing feeling of spectacles, there is a demand for a spectacle lens with a small convex surface height and a small change in image magnification at the intermediate portion 13.

  FIG. 3 shows the surface refractive power along the vertical reference line Y of the outer surface (object side surface) 19A and the inner surface (user side surface, eyeball side surface) 19B of the spectacle lens 10 according to the embodiment of the present invention. The change in (average surface refractive power) is shown. This spectacle lens prescription 10 has a power S of +3.00 and an addition add of 2.00. The refractive index of the lens substrate is 1.67, the center thickness is 1.1 mm or more, the edge thickness is 0.5 mm or more, and the center thickness + edge thickness is 3.2 mm or more. is there. Further, the surface refractive power of the outer surface 19A is designed to be the smallest, that is, to be thin, under the condition that the inner surface 19B is not convex in any part.

  The vertical reference line Y is a vertical reference line passing through the eye point (fitting point) Pe of the spectacle lens 10 as shown in FIG. 2, and the upper point is positive and the lower part is negative with the eye point Pe as the origin (0 point). This is the reference line for the vertical coordinate. As a reference line in the vertical direction of the spectacle lens 10, a main gazing line (main meridian) Y ′ connecting positions on the lens that becomes the center of the field of view when performing far vision, intermediate vision, and near vision is used. May be.

  The solid line in FIG. 3 shows the change in the average surface power of the outer surface 19A of the spectacle lens 10, and the broken line shows the change in the average surface power of the inner surface 19B. The spectacle lens 10 is an inner surface progressive lens, and the inner surface 19B has a distance portion 11 mainly used when viewing an object at a long distance and a near portion 12 mainly used when looking at an object at a short distance. And an intermediate portion 13 in which the power gradually changes between the distance portion 11 and the near portion 12.

  The outer surface (object-side surface) 19A of the spectacle lens 10 includes a first region 21 having an average surface refractive power of a first value D1, and a second region 22 having an average surface refractive power of a second value D2. The average surface refractive power increases from the first value D1 to the third value D3 and decreases from the third value D3 to the second value D2 between the first region 21 and the second region 22. 3rd area | region 23 to be included. The first region 21 of the outer surface 19A faces a part of the distance portion 11 of the inner surface 19B, and the second region 22 faces the near portion 12. The third region 23 of the outer surface 19A faces the lower side of the distance portion 11 and the intermediate portion 13 of the inner surface 19B between the first region 21 and the second region 22.

  In the eyeglass lens 10, the first value D1 and the second value D2 are 5D (diopter), and the third value D3 is 7D. Further, with respect to the eye point Pe (Y = 0), the Y coordinate Ya of the boundary point (first point) P1 between the first region 21 and the third region 23 is 4 (Ya = 4), The Y coordinate Yc of the point (third point) P3 where the average surface refractive power becomes the maximum value (third value) D3 in the third region 23 is −4 (Yc = −4). The Y coordinate Yb of the boundary point (second point) P2 with the second region 22 is −14 (Yb = −14).

  The inner surface 19B further corresponds to each of the first region 21, the second region 22, and the third region 23 of the outer surface 19A, and the fourth region 24 having an average surface refractive power of the fourth value D4. The average surface power between the fourth region 24 and the fifth region 25 is between the fourth value D4 and the sixth value D6. And a sixth region 26 that decreases from the sixth value D6 to the fifth value D5. Further, in the spectacle lens 10, since the distance portion 11 is included in the sixth region 26, when the fourth value D4 increases from the fourth value D4 to the sixth value D6 in the sixth region 26, the fourth region 26 The value D4 reaches the sixth value D6 via the seventh value D7.

  In this spectacle lens 10, the fourth value D4 is 2D, the fifth value D5 is 0D, the sixth value D6 is 3.2D, and the seventh value D7 is 3D. The Y coordinate of the boundary point (fourth point) P4 between the fourth region 24 and the sixth region 26 is the same as the Y coordinate Ya of the first point P1, and the average surface refractive power is maximum in the sixth region 26. The Y coordinate of the point (sixth point) P6 that becomes the value (sixth value) D6 is the same as the Y coordinate Yc of the third point, and the boundary point (first point) between the sixth region 26 and the fifth region 25 5 points) The Y coordinate of P5 is the same as the Y coordinate Yb of the second point. The Y coordinate of the seventh point P7 of the seventh value D7 is the boundary between the distance portion 11 and the intermediate portion 13, and in the eyeglass lens 10, it is the same coordinate (Y = 0) as the eye point Pe.

  FIG. 4 shows an aberration distribution when viewed through the object-side surface (outer surface) 19A, eyeball-side surface (user-side surface, inner surface) 19B, object-side surface, and eyeball-side surface of the eyeglass lens 10. An equivalent spherical power distribution is shown.

  As shown in FIG. 3, when attention is paid to the third region 23 of the spectacle lens 10, first, it is a boundary between the distance portion 11 and the intermediate portion 13 from the first point P <b> 1 inside the distance portion 11. In the range 23a up to the seventh point P7 (eye point Pe), the power S does not change and the surface refractive power (base curve) D of the outer surface 19A increases (the curvature increases and the curvature radius decreases). Therefore, according to equation (8), the magnification of the image gradually increases.

  In the range 23b from the seventh point P7 to the third point P3 where the base curve is maximum, the frequency S is gradually increased and the base curve D is gradually increased because the intermediate portion 13 is reached. Therefore, the increasing tendency of the image magnification becomes large.

  In a range 23c from the third point P3 to the second point P2, which is a boundary with the near portion 12, the frequency S gradually increases and the base curve D gradually decreases. Therefore, in this range 23c, a change in image magnification is suppressed. For this reason, if the PC screen or the like can be seen in the range 23c from the sixth point P6 to the second point P2 where the base curve D is maximized, screen deformation and shaking can be suppressed.

Accordingly, it is desirable that the coordinate Ya of the first point P1, the coordinate Yb of the second point P2, and the coordinate Yc of the third point P3 satisfy the following conditions. In the following formula, the unit is mm.
Ya>Yc> Yb (1)

  The condition of the expression (1) is that the third point P3 at which the base curve D reaches a peak is between the boundary P1 between the distance portion 11 and the intermediate portion 13 and the boundary P2 between the intermediate portion 13 and the near portion 12. Indicates that it is located.

The lower the boundary point (first point) P1, the easier it is to make the lens thinner. On the other hand, as described above, the portion 23c between the third point P3 and the second point P2 in the third region is a portion where the change in the magnification of the image is small, and if the first point P1 is close to the eye point Pe, the magnification of the image It is difficult to secure a wide change portion 23c. Therefore, it is preferable that the first point P1 satisfies the condition of the following expression (2).
Ya ≦ 15 (2)

It is desirable that the first point P1 further satisfies the following conditions.
0 ≦ Ya ≦ 15 (2 ′)

Since the change in the magnification of the image of the image 23c between the third point P3 and the second point P2 is small, the third point P3 is displayed on the PC screen in order to make the spectacle lens 10 suitable for viewing the PC screen. It is preferable that the position near the upper end is viewed, and the second point P2 is a position viewed near the lower end of the PC screen. For this reason, it is desirable that the respective coordinates Yc and Yb satisfy the conditions of the following expressions (3) and (4).
−5 ≦ Yc ≦ 10 (3)
−25 ≦ Yb ≦ −5 (4)

Further, the areas 23a and 23b between the first point P1 and the third point P3 are areas in which the tendency of the image magnification change is relatively large as described above. If the lengths of the areas 23a and 23b are too short, the image The tendency of the change in magnification increases, making it difficult to see. On the other hand, if the lengths of the areas 23a and 23b are too long, the length of the area 23c between the third point P3 and the second point P2 suitable for viewing the PC screen becomes short. Therefore, it is preferable that the coordinate Ya of the first point P1, the coordinate Yc of the third point P3, and the coordinate Yb of the second point P2 satisfy the conditions of the following expressions (5) and (6).
Ya-Yc ≧ 4 (5)
Yc−Yb ≧ 10 (6)

The value D3 of the base curve D at the third point P3 is a value that can ensure that the change from the value D3 of the base curve D to the value D2 in the region 23c can suppress the change in magnification of the image due to the increase in the frequency S. Good. Specifically, it is desirable to satisfy the condition of the following expression (7).
MAX (D1, D2) + 1 ≦ D3 ≦ (n−1) /0.015 (7)

  That is, if the third value D3 is not larger than the first value D1 and the second value D2 by 1D or more, the third region 23 accompanied with the increase and decrease of the base curve D cannot be formed. The maximum value of the third value D3 can be determined by securing the width as a spectacle lens as follows.

First, in spectacles using a progressive power lens, it is recommended that the vertical width of the frame is 30 mm or more. At this time, if the curvature radius of the object-side surface is set to 15 mm or less, a necessary frame diameter may not be secured. Therefore, it is preferable that the maximum value Dmax that the third value D3 can take satisfies the following expression (11). The unit is diopter.
Dmax = (n−1) / r = (n−1) /0.015 (11)

    Here, n is the refractive index of the lens material, and r is the radius of curvature (m) of the object side surface.

In the above equation (11), when the refractive index n of the lens material is 1.661, the maximum value Dmax is expressed by the following equation (12).
Dmax = (1.662-1) × 1000 / 15≈44.13 (D) (12)

  The eyeglass lens 10 of this example satisfies the above conditions (1) to (7).

  FIG. 5 compares the change in average surface refractive power of the outer surfaces 19A and 19B (FIG. 5A) of the spectacle lens 10 of this example with that of Comparative Example 1 (inner surface progressive lens) (FIG. 5B). This is shown in comparison with Example 2 (double-sided progressive lens, in which the surface addition on the object side surface is negative (outside reverse addition) (FIG. 5 (c)). As shown in the design conditions of Example, Comparative Example 1 and Comparative Example 2, the lenses have the same spectacles specifications.

  FIG. 7 collectively shows the magnification at the third point P3, the magnification at the second point P2, and the magnification difference for each of the spectacle lens of the example and the spectacle lenses of Comparative Examples 1 and 2. . As can be seen from this figure, the third point P3 and the third point P3 are the same as those of the double-sided progressive lens of Comparative Example 2 in which the magnification difference of the eyeglass lens 10 of the example is the smallest and the objective is to reduce the magnification difference. As long as it is limited to the region 23c between the two points P2, the difference in magnification of the spectacle lens 10 of the example is the smallest. Therefore, if limited to applications such as viewing a PC screen, the spectacle lens 10 of the embodiment can reduce the feeling that the image looks like a trapezoid and can provide spectacles with a good wearing feeling.

  One factor that the spectacle lens 10 of this example has a small magnification difference with respect to the double-sided progressive lens is that the base curve in the third region 23 can be understood by comparing FIG. 5A and FIG. Since D is increased or decreased, the peak value (third value) D3 can be increased with respect to the addition. With the spectacle lens 10 of this example, the spectacle lens 10 with a smaller magnification difference can be provided by further increasing the peak value D3.

  FIG. 8 is a diagram comparing the thicknesses of the lens of Example and Comparative Example 2, and shows the relationship between the Y coordinate and the convex surface height (Z coordinate, sag value) of the object side surface. As shown in the figure, in contrast to the spectacle lens 10 of the present example, the double-sided progressive lens of Comparative Example 2 has the same design as the spectacle lens 10 of the present example in the base curve D in the near portion 12. The value of the base curve D in the distance portion 11 increases. For this reason, the curvature of the distance portion 11 increases, and therefore the thickness of the spectacle lens of the distance portion 11 (the height of the convex surface with respect to the eye point Pe) increases. On the other hand, in the case of the eyeglass lens 10 of this example, the base curve D of the distance portion 11 can be set to be the same as that of the near portion 12, and the same thickness as the inner surface progressive lens of the comparative example 1 ( It is possible to provide a spectacle lens with a small difference in magnification. Therefore, it is possible to provide the glasses 1 with a better wearing feeling.

  In the eyeglass lens 10 of this example, the base curve D of the distance portion 11 and the base curve D of the near portion 12 need not be the same. Therefore, depending on the design, there is a possibility of providing a spectacle lens that is thinner (smaller in convex height) than the inner surface progressive lens of Comparative Example 1.

  Further, the spectacle lens 10 of the present example can be designed so as to reduce the difference between the magnification of the image viewed through the distance portion 11 and the magnification of the image viewed through the near portion 12. Such a spectacle lens is designed such that FIGS. 5A and 5C are combined, and the magnification difference in the region 23c suitable for viewing the screen of the PC can be further reduced. However, since the design of the distance portion 11 is the same as that of the double-sided progressive lens of the comparative example 2, the convex surface height of the entire spectacle lens is the same as that of the comparative example 2. Therefore, although the effect of reducing the thickness of the spectacle lens can be achieved with respect to the effect of reducing the magnification difference in the region 23c suitable for viewing the PC screen, the overall convex surface height is substantially the same as that of the comparative example 2. there is a possibility.

  FIG. 9 is a flowchart showing an example of a design and manufacturing method of the spectacle lens 10. First, in step 51, the basic shape of the inner surface progressive surface including the average surface refractive power of the distance portion 11 and the near portion 12 of the inner surface 19B is determined from the spectacle prescription. In step 52, the upper end (first point) P1 of the outer surface 19A based on the spectacle prescription (spectacle spec) and the conditions (prescription) such as use, the point at which the maximum value is taken (third point) P3, and the lower end (second point) Determine the coordinates of P2. In step 53, the base curve of the outer surface 19A is taken into consideration in the third region 23, particularly in the region 23c where the difference in image magnification is desired to be reduced, with respect to the average surface refractive power of the inner surface 19B determined in step 51. Determine the shape of D.

  Further, in step 54, the shape of the inner surface 19B is determined so that the performance of the inner surface progressive surface is exhibited according to the base curve D of the outer surface 19A. In step 55, the spectacle lens 10 including the outer surface 19A and the inner surface 19B is molded.

  FIG. 10 shows a schematic configuration of an example of a spectacle lens design apparatus 70. The design apparatus 70 includes first to third units (functions) 71 to 73. The first unit 71 is a unit that sets a progressive surface including the distance portion 11 and the near portion 12 based on the spectacle prescription. The second unit 72 sets the first region 21, the second region 22, and the third region 23 on the outer surface 19 </ b> A, and the value D <b> 1 of the first region 21 and the value D <b> 2 of the second region 22 The peak value D3 of the third region 23 is determined. In the second unit 72, the first region 21 is included in the distance portion 11, the second region 22 is included in the near portion 12, and the third region 23 includes the intermediate portion (progression portion) 13. Set the area as follows.

  The third unit 73 is a unit that simulates how the wearer (user) sees the spectacle lenses 10L and 10R designed as described above. An example of the unit 73 is an image display device, and it is possible to virtually experience the corrected visual acuity in which the difference between the left and right magnifications is reduced using a head mounted display or the like.

  By using this design device 70, the user can experience the degree of distortion and shaking of the image mainly seen in the application desired by the user at the eyeglass dealer. Therefore, by using this design device 70, the user can experience that a comfortable visual field can be obtained with the glasses 1 designed as described above.

  In the present embodiment, a progressive multifocal (progressive refractive power) lens for spectacles has been described as an example, but the present invention is not limited to a progressive multifocal lens. The present invention can also be applied to a bifocal lens, a trifocal lens with an intermediate power, and the like.

DESCRIPTION OF SYMBOLS 1 Glasses, 10, 10L, 10R Glasses lens 11 Distance part, 12 Near part, 13 Middle part (progressive part)
21 1st area | region, 22 2nd area | region, 23 3rd area | region 19A Object side surface, 19B Eyeball side surface 20 Frame, 70 Lens design apparatus

Claims (10)

The object side surface is
A first region having an average surface power along the main line of sight or vertical reference line of a first value;
A second region where the average surface power is a second value;
Between the first region and the second region, the average surface power increases from the first value to a third value and decreases from the third value to the second value. A third region;
Eyeglass lenses including In claim 1,
The distance used mainly when looking at objects at long distances, the near part used mainly when looking at objects at short distances, and the frequency gradually between the distance and near parts Including an intermediate part that changes,
The eyeglass lens, wherein the first region of the object side surface is at least a part of the distance portion, and the second region is at least a portion of the near portion. In claim 1 or 2,
A user-side surface faces each of the first region, the second region, and the third region of the object-side surface, and the average surface refractive power is a fourth value having a fourth value. The average surface power between the fourth value and the sixth value between the fourth value and the fifth value. And a sixth region that increases to the value and decreases from the sixth value to the fifth value. 4. The boundary point Ya between the first region and the third region on the vertical reference line with the eye point of the spectacle lens as the origin, and the average surface refractive power according to claim 1. The lens for spectacles, wherein the point Yc which is the third value and the boundary point Yb between the third region and the second region satisfy the following conditions.
Ya>Yc> Yb
Ya ≦ 15
−5 ≦ Yc ≦ 10
−25 ≦ Yb ≦ −5
However, the unit is mm. 5. The spectacle lens according to claim 4, wherein the points Ya, Yc, and Yb satisfy the following conditions.
Ya-Yc ≧ 4
Yc−Yb ≧ 10 6. The spectacle lens according to claim 1, wherein when the first value is D1, the second value is D2, and the third value is D3, the following condition is satisfied.
MAX (D1, D2) + 1 ≦ D3 ≦ (n−1) /0.015
However, the unit is diopter, n is the refractive index of the material, and MAX (D1, D2) is a function that selects the larger one of D1 and D2. A method for manufacturing a spectacle lens,
A first region having an average surface power along the main line of sight or vertical reference line of a first value;
A second region where the average surface power is a second value;
Between the first region and the second region, the average surface power increases from the first value to a third value and decreases from the third value to the second value. A third region;
A method for manufacturing a spectacle lens, comprising: forming an object-side surface comprising: 8. The distance portion used mainly for viewing a long-distance object and used mainly for viewing a short-distance object at the same time as forming the object-side surface or at the same time. Forming a user-side surface comprising a near portion and an intermediate portion in which the power gradually changes between the distance portion and the near portion;
The method for manufacturing a spectacle lens, wherein the first region of the object-side surface faces at least a part of the distance portion, and the second region faces at least a portion of the near portion. An apparatus for designing a multifocal lens for spectacles including a distance portion and a near portion having different powers,
A first unit for setting a user side surface including the distance portion and the near portion;
A first region having an average surface power along a main gaze line or a vertical reference line having a first value; a second region having an average surface power of a second value; the first region; A third region in which the average surface power increases from the first value to the third value and decreases from the third value to the second value between the second region and the second region; A second unit for setting an object-side surface, wherein the first region faces at least a part of the distance portion, and the second region faces at least a portion of the near portion. And a second unit for setting the object-side surface.   10. The apparatus according to claim 9, further comprising a unit that simulates a state viewed through the multifocal lens for spectacles provided with the user-side surface and the object-side surface.

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