CN1831582A - Design Method of Progressive Power Lens Group - Google Patents

Abstract

Provided is a method of designing a progressive refracting power lens group, in which the refractive indexes of materials of progressive refracting power lenses are identical and which enables viewing an object in the same attitude as with a lens replaced with a progressive refracting power lens, having a different refractive power in the progressive refracting power lens group, where the design concepts of the progressive refracting power lenses have been unified, even when it is changed. The position of a second refractive section is changed vertically, to make prism refracting power constant at a refractive power measurement point of the second refractive section for seeing an object at a close range, and a progressive zone length is increased or decreased, according to the refractive power of the second refractive section.

Description

Design Method of Progressive Power Lens Group

technical field

The invention relates to a design method of a progressive dioptric power lens set, which is a collection of progressive dioptric power lenses based on the same design idea for compensating the lack of adjustment power caused by presbyopia.

Background technique

The progressive refractive power lens has: an upper distance part for observing relatively far; a lower near part for observing relatively near; . Generally, the distance between the far part and the near part, that is, the length of the progressive part, is called the progressive zone length. In progressive power lenses, since there is no boundary line between the distance portion and the near portion on the lens, it is difficult to judge the length of the progressive zone from the lens. However, in the description of the instruction manual, the transition portion between the distance part and the progressive part on the main meridian, from the region where the refractive power is approximately fixed to the region where the refractive power changes, is taken as the lower end of the far part, and the transition part between the progressive part and the near part The upper end of the near-use part is the transition part from the refractive power changing area to the near-use area where the refractive power is roughly fixed, and the distance between the lower end of the far-use part and the upper end of the near-use part is called the progressive zone length.

As shown in Fig. 2, on the progressive refractive power lens 10 that is put into the sales store, there are positioning marks or assembly points F used when carrying out the frame-in process of being loaded into the spectacle frame with erasable ink, for measuring The refractive power used for distance and the refractive power of the added degree refer to the circle and so on. The center of the distance dioptric power reference circle 1 is called the distance dioptric power measurement point Dp, and the center of the addition power reference circle 2 is called the near dioptric power measurement point Np. Although there are slight differences according to spectacle lens manufacturers, generally the fitting point F is set at the transition point from the distance part to the progressive part, and the upper end of the addition reference circle 2 roughly coincides with the upper end of the near part. Therefore, the distance in the vertical direction from the assembly point F to the upper end of the addition degree reference circle 2 can be simply regarded as the length of the progressive zone.

The near portion region is generally located on the outer periphery away from the central portion of the lens. Due to the influence of the distance refractive power or addition of the lens, the peripheral part of the lens produces a very large prism refractive power. For example, the following group of progressive dioptric power lenses is provided to demanders with the same product name: uniformly designed according to a certain design idea, so as to meet the needs of progressive dioptric power lenses with wide bright field of vision for distance use and wide bright field of vision for near use. The basic elements of the same wearing purpose. The progressive zone length of each progressive dioptric power lens in the progressive dioptric power lens group of the same trade name is fixed. That is, the position of the near portion is fixed regardless of the value of the far refractive power.

In addition, as shown in, for example, Patent Document 1 below, it has conventionally been conceived to change the inset amount of the near portion based on the prism effect of the near portion. However, this is a structure for accurately overlapping the left and right lines of sight during binocular vision. In addition, before Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, Patent Document 5, etc. also disclosed inventions related to positioning marks that can cope with changes in the position of the near-use part, but they only mentioned Use the shift corresponding to the inner bias.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2003-329984

[Patent Document 2] Japanese Unexamined Patent Publication No. 2001-51241

[Patent Document 3] Japanese Patent Laid-Open No. 2002-311396

[Patent Document 4] Japanese Patent Laid-Open No. 2003-131175

[Patent Document 5] Japanese Patent Laid-Open No. 2003-131176

However, the amount of prisms at the near power measurement point Np changes according to the distance power or addition, and thus the position of the object point when observing an object through the near power measurement point Np changes according to these powers. For example, in a concave lens with negative refractive power, as shown in FIG. 3(a), the position of the object point is different on the line of sight L1 and the line of sight L2, which has a relatively positive refractive power at the near part shown by the solid line. The line of sight L2 is the line of sight towards the center of rotation O of the eyeball when the concave lens 11 of refractive power observes an object. Therefore, in order to observe a specific object point with such a concave lens with different refractive power, as shown in FIG. For example, in order to make the progressive dioptric power lens 12 with relatively negative dioptric power at the near use portion relative to the concave lens 11 with relatively positive dioptric power at the near use portion, and the same position of the object point, it is necessary to make the progressive dioptric power with relatively negative dioptric power at the near use portion The lens 12 points slightly upwards so that the object point is observed through the near power measurement point Np.

The same is true for a convex lens with positive refractive power. As shown in FIG. The line of sight L4 when observing an object with respect to the convex lens 21 of positive refractive power is indicated by a dotted line, and is the line of sight of the progressive dioptric power lens 22 with the refractive power of the near portion indicated by the dotted line having relative negative refractive power. Therefore, in order to observe a specific object point with such a convex lens with different refractive power, as shown in FIG. In the case of spectacle lenses, it is necessary to change the orientation of the face up and down in order to observe the object through the near refractive power measurement point Np.

In this way, the progressive dioptric power lens has a part for close-distance observation at the edge of the lens with increased prism power, and it is necessary to change the tilt angle of the head according to the refractive power of the lens to observe. In the progressive dioptric power lens group of the same brand name, just When changing to a new lens, it will be troublesome and inconvenient until you get used to it.

Contents of the invention

The present invention is completed in view of the above-mentioned circumstances, and its purpose is to provide a design method for a progressive power lens group. Even if you use a progressive refractive lens that has a different refractive power than the conventional lens, you can observe objects in the same posture as the conventional lens.

In order to achieve the above object, firstly, the present invention provides a design method of a progressive dioptric power lens group, which is characterized in that, for the following progressive dioptric power lens group: the progressive dioptric power lens group is a collection of progressive dioptric power lenses, each progressive The diopter lens has a first diopter having a diopter for observing an object located at a predetermined distance, a second diopter having a dioptric power used for observing an object located at a short distance, and a diopter having a diopter whose dioptric power is changed from the first diopter to an object located at a short distance. A progressive portion that gradually changes from the optical portion to the second refractive portion, and the progressive refractive power lens set satisfies the following conditions: the first refractive portion with different refractive power can be selected, and the first refractive power with the same refractive power can be selected. The refractive part selects multiple addition degrees, the refractive index of the material is the same, and the design idea of each progressive refractive power lens is unified, and each progressive refractive power lens is designed as follows: Between the progressive refractive power lenses with the same addition degree, In the side where the refractive power of the first diopter is smaller, the distance in the vertical direction between the fitting point and the diopter power measurement point of the second diopter is shorter, and the dioptric power in the first diopter is the same Among the progressive dioptric power lenses, the one with the larger addition power has a longer vertical distance between the fitting point and the diopter power measurement point of the second refraction unit.

A progressive-power lens set sold under the same brand name includes a plurality of progressive-power lenses whose materials have the same refractive index and which are unified in the same design concept. In addition, the refractive power of the first refractive part suitable for the wearer can be selected from a plurality of progressive refractive power lenses with different refractive powers of the distance part or the first refractive part, and different refractive powers can be selected for the same first refractive part. The addition degree of , the first diopter is located on the upper part of the lens and is used to observe objects located at an intermediate distance. In the past, the progressive zone lengths of the progressive power lenses included in a progressive power lens set were fixed.

However, as far as the present inventors know, by changing the position of the second refracting part for observing an object located at a short distance in the up and down direction, the prism refractive power at the diopter power measurement point of the second refracting part is fixed, even if Even when changing to a progressive power lens with a different refractive power than the previous lens, it is possible to observe objects with the same posture as the previous lens. In order to fix the refractive power of the prism at the refractive power measurement point of the second refractive part, it is achieved by the following method: when comparing the two lenses in the progressive refractive power lens group, if the addition is the same, then in the distance part or for In a lens having a smaller refractive power of the first diopter part located on the upper part of the lens for observing an object located at an intermediate distance, that is, a lens having a more negative refractive power, the first diopter part has a larger refractive power, that is, has a larger refractive power. Compared with the lens with the refractive power on the positive side, the edge of the lens is thicker; in the second refraction part for observing the near distance existing in the edge of the lens, since the refractive power of the prism increases, the upper end of the second refraction part As a result of the placement on the upper side, the progressive belt length is shortened. In addition, it is achieved by the following method: When comparing two lenses in a progressive power lens group, if the refractive power of the first diopter is the same, the lens with a large addition has a higher second diopter than the lens with a small addition. The refractive power of the optical part is on the positive side, and the refractive power of the prism is reduced. Therefore, the upper end of the second refractive part is arranged on the lower side, and as a result, the progressive zone length is increased.

In addition, since it is difficult to judge the length of the progressive zone from the lens, the length of the progressive zone is substantially represented by the distance in the vertical direction between the fitting point and the refractive power measurement point of the second refracting part, which is easy to actually measure.

Second, the present invention provides a method for designing a progressive dioptric power lens group, which is characterized in that, in the design method for the first progressive dioptric power lens group, each progressive dioptric power lens is designed as follows: When the astigmatic refractive power at the dioptric power measurement point is not zero, between progressive dioptric power lenses having the same refractive power as that of the first refracting part, the astigmatic dioptric power of the dioptric power of the first refracting part In the progressive refractive power lens having a small vertical component, the distance in the vertical direction between the fitting point and the refractive power measurement point of the second refracting part is shorter.

Even when a refractive surface such as a cylindrical refractive surface or a toric surface for correcting astigmatism is provided, a prism refractive power is generated thereby. When lenses with the same addition degree and first refractive power in the progressive power lens group are compared with each other, the refractive power of the vertical direction component of the astigmatic refractive power is small, that is, the lens with the refractive power on the more negative side in the base direction The refractive power of the prism is increased, so the upper end of the second refracting part is arranged on the upper side. As a result, by shortening the length of the progressive zone, the refractive power of the prism at the dioptric power measurement point of the second refracting part is achieved within the lens group. keep it fixed.

Thirdly, the present invention provides a method for designing a progressive dioptric power lens set, which is characterized in that, in the design method of a progressive dioptric power lens set described in technical solution 1 or 2, the assembly point and the second dioptric power The distance in the vertical direction between the refractive power measurement points of the section is set as the distance in the vertical direction from the following first transition position to the second transition position. The first transition position is: on the principal meridian, from the The transition position of the region where the refractive power of the first refracting part is approximately constant to the region where the refractive power changes, the second transition position is: between the progressive part and the second refracting part, transitioning from the region where the refractive power changes to The location of the near zone of approximately constant refractive power.

If the actual progressive zone length of the lens can be determined, there is no need to use the distance that is simply considered to be the progressive zone length.

Description of drawings

1( a ), ( b ) are plan views showing an example of lenses designed by the method for designing a progressive-power lens set of the present invention.

Fig. 2 is a plan view showing the layout of a progressive power lens.

Fig. 3 shows a difference in vision caused by the refractive power of a concave lens, (a) shows the line of sight when the position of the lens is not changed, and (b) shows the line of sight when the lens is tilted.

Fig. 4 shows a difference in vision caused by the refractive power of a convex lens, (a) shows the line of sight when the position of the lens is not changed, and (b) shows the line of sight when the lens is tilted.

5( a ) and ( b ) are conceptual diagrams showing the vertical direction component of the refractive power of astigmatism.

Detailed ways

Hereinafter, an embodiment of a method for designing a progressive-power lens set according to the present invention will be described, but the present invention is not limited to the following embodiments.

The progressive dioptric power lens design method of the present invention designs each progressive dioptric power lens of the progressive dioptric power lens group as a collection of progressive dioptric power lenses as follows: the same product name is provided to those who need it, and the design concept is unified to meet the needs of long-distance users. The basic elements of progressive diopter lenses, such as wide bright vision and wide near vision, have the same purpose of wearing.

Progressive power lenses are mainly used as vision correction lenses for presbyopia with weakened accommodation. As shown in Fig. 2, the progressive dioptric power lens has on one lens: the upper first diopter 31 having the refractive power required for observing objects at a distance or at an intermediate distance, and the upper first diopter 31 having the refractive power required for observing near objects. The lower part of the second refraction part 32 of the refractive power, and the progressive part 33 of the continuous change of refraction power from the first refraction part 31 to the second refraction part 32, there is no boundary line on it, so the fashion is good.

There are various design types of progressive power lenses, for example, there are design types according to usage. In the so-called distance-near type of progressive power lenses, there are: a distance part above the lens for viewing distant objects, a near part below the lens for observing near objects, and a gradual progression from the upper starting point to the lower part. A progressive section in which the refractive power gradually changes between end points. The design idea is: arrange both the far part and the near part in a well-balanced manner, so that the length of the progressive zone is about 10-16mm, so that the eyes are easy to turn when observing the near. The assembly point is generally consistent with the remote center, that is, the progressive starting point. The so-called intermediate-near type of progressive refractive power lens has: the distance part at the upper end of the lens for observing distant objects, the near part at the bottom of the lens for observing near objects with a relatively wide area, and the refractive power between them. The gradual part that changes gradually. The length of the progressive zone is increased to about 19-25mm in order to achieve a wide field of view during intermediate vision. The fitting point is generally located at the progression of the object viewed at a distance of around 1 m. In the so-called near-near type progressive refractive power lens, there are: an intermediate portion above the lens for observing an object located at an intermediate distance, a near portion below the lens for observing a near object with a relatively wide area, and A progressive section in which the refractive power gradually changes between. The length of the progressive zone is increased to about 19-25mm in order to achieve a wide field of view during intermediate vision. Furthermore, in the design of the distribution of distortion aberration and astigmatism, it can be roughly divided into: the aberration-concentrated type that widens the distance part and the near part, and concentrates aberrations on the narrow progressive part; and narrows the distance part. The aberration dispersion type that spreads the aberration in the middle part by widening the progressive part.

The progressive dioptric power lens set that is a collection of multiple progressive dioptric power lenses developed under the same trade name is designed as follows: the refractive index of the lens material is the same, and the following design ideas are unified, and the progressive dioptric power lenses that constitute the progressive dioptric power lens set meet common wearing requirements Purpose, the design concept is the above-mentioned design type according to the purpose, the distribution of aberrations, the change of the refractive power of the progressive part, the width of the bright field of the first refraction part, the width of the bright view of the second refraction part, and the progressive refraction. Whether the surface is on the object side (outer side) or the eyeball side (inner side), etc.

Since the progressive zone length is an important design item that determines the design idea of progressive dioptric power lenses, it is usually the same in each progressive dioptric power lens in the same progressive dioptric power lens group.

However, in the progressive dioptric power lens group having the same progressive zone length, when the power of the eye increases and other progressive dioptric power lenses with different diopters (refractive power) are purchased from the same progressive dioptric power lens group, the near dioptric power measurement point Np The position of the object point when observing the object is different from that of the lens used in the past. Therefore, in order to observe the position of the object point in the same way, it is necessary to change the orientation of the face up and down and change the wearing angle of the lens so that the position of the object point observed through the lens is the same. It is troublesome and inconvenient when you just change to a new lens until you get used to it.

Generally, the refractive power of the second refracting part (near part) is mathematically smaller, that is, the refractive power of the near part has a more negative refractive power. The prism power becomes larger. In Fig. 3a the state of refraction in two negative power lenses of different power is shown. The lens 12 shown in dashed lines has a more negative refractive power than the lens 11 shown in solid lines. Therefore, regarding the prism power in the 270-degree direction at the near refractive power measurement point Np, the lens 12 is larger, and the ray L2 shown by the dotted line passing through the lens 12 is lower than the ray L1 shown by the solid line passing through the lens 11. refraction. In the case of observing objects at the same position with lenses 11 and 12, as shown in Figure 3 (b), it is necessary to lift the entire lens 12 so that the positions of the light rays are aligned. For this reason, the wearer of the lens 12 must stretch out Drop your jaw and lift your face.

In the case of a positive refractive power lens, as shown in FIG. The light ray L4 indicated by a dotted line passing through the lens 22 is refracted more downward than the ray L3 indicated by a solid line passing through the lens 21 indicated by a solid line. Therefore, as shown in FIG. 4( b ), the wearer of the lens 21 needs to retract his jaw and lower his face to observe an object compared to when wearing the lens 22 .

The above phenomenon is due to the fact that the lenses with different refractive powers have the same position of the near refractive power measurement point Np of the second refractive part, that is, the length of the progressive zone is fixed. In the design method of the progressive dioptric power lens set of the present invention, the position of the near dioptric power measurement point Np of the second refraction portion between the progressive dioptric power lenses constituting the lens set is changed according to the refractive power of the second dioptric portion of the lens. , the refractive power of the prism at the measurement position Np is fixed, so that no matter which lens in the same lens group is selected, there is no difference at all in the posture when observing the object, or even if there is a slight difference, it can be suppressed so that the wearer does not feel discomfort degree of wearability. That is, in the case where the refractive power of the second refracting part is a more negative refractive power, the prism power in the base 270-degree direction can be reduced by making the position of the near-use refractive power measurement point Np of the second refracting part closer to the center of the lens. , since it is closer to the line of sight of a lens with a more positive refractive power, the difference in wearing feeling can be reduced. In the design method of the progressive diopter lens set of the present invention, the progressive zone length is removed from the concept of the unified design idea.

The prism refractive power at the near refractive power measurement point Np of the second diopter changes according to the refractive power and addition of the first diopter. In order to keep the prism refractive power at the near dioptric power measuring point Np of the second refracting part fixed no matter which lens in a progressive dioptric power lens group is selected, the lens design in the progressive dioptric power lens group is designed under the condition that the addition degree is fixed Result: The progressive zone length of the lens with the more negative refractive power of the first refractive part is shorter. However, since the length of the progressive zone is difficult to measure in an actual lens, in this specification, the near refractive power measurement point of the second diopter represented by the assembly point and the addition degree reference circle is preferably the distance from the upper end. The distance in the vertical direction simply represents the progressive band length. The premise of this simple progressive zone length is that the addition measurement position and the position of the upper end of the second refracting part are fixed. Of course, if the length of the progressive zone can be actually measured, that is, the distance in the vertical direction from the following first transition position to the second transition position, the measured value is preferably used. The first transition position is: on the main meridian, from The transition position of the area of the first refracting part where the refractive power is approximately fixed to the area where the refractive power changes; the second transition position is: between the progressive part and the second refracting part, the transition from the area where the refractive power changes to the area where the refractive power is approximately fixed The location of the near-use area.

In addition, the lenses in the progressive dioptric power lens group are designed such that: in a progressive dioptric power lens with fixed diopter power of the first diopter part in a progressive dioptric power lens group, the progressive zone length of the lens with larger addition is longer. This is because: when the refractive power of the first refractive part is fixed, as the addition increases, the refractive power of the second refractive part transitions to the positive side, and the refractive power of the prism decreases.

In addition, the lenses in the progressive dioptric power lens group are designed such that when the dioptric power of the second refraction part is fixed, the progressive zone length of the lens with a larger addition is shorter. This is because the refractive power of the second diopter is the same, and the refractive power of the first diopter further becomes negative as the addition increases.

The aforementioned progressive zone length is a relative value when comparing the lenses in the progressive power lens set with each other. If the design idea of the lens is different, the absolute value of the progressive zone length changes. In addition, if the refractive index of the lens material is different, the prism refractive power will be different even if the refractive power is the same, so the absolute value of the progressive zone length will also change.

It is well known that if the progressive zone length is shortened in a progressive power lens, the distortion or blurring of the image felt when wearing it increases. Therefore, it may be considered that shortening the progressive zone length by bringing the near-use portion measurement position Np closer to the lens center in a lens with a more negative refractive power results in a design disadvantage. However, according to the studies of the present inventors, it has been found that generally, people wearing lenses with negative refractive power feel less distortion or blurring of images than people wearing lenses with positive refractive power. This is considered to be: for lenses with negative refractive power, since the image looks smaller, it is difficult to feel the distortion or shaking of the image. Therefore, even if the progressive zone length of the negative refractive power lens is shortened, the wearing discomfort caused by image distortion or shaking does not pose a problem. Conversely, for positive diopter lenses that are prone to distortion/shaking, the progressive belt length becomes longer, which can reduce the distortion of the lens, so the design method of the progressive diopter lens group of the present invention not only improves the wearing posture, but also reduces the discomfort during wearing feel.

Fig. 1 shows a lens material with a refractive index of 1.67, an inner progressive power lens with the progressive refractive surface set as the eyeball-side refractive surface, a so-called far-near progressive power lens, and a progressive power lens with a unified design concept A design example of two progressive-power lenses having different refractive powers.

Fig. 1(a) is a progressive dioptric power lens 101 with spherical refractive power S-8.00 diopter (hereinafter expressed as D) and addition degree ADD 2.00D, and Fig. 1(b) is a progressive dioptric power lens 102 with S-4.00D and ADD 2.00D. Each figure shows a distance refractive power reference circle 1 , a fitting point F, a near refractive power reference circle (additional power measurement range) 2 , a near refractive power measurement point Np, and a principal meridian M. The main meridian M is offset from the assembly point F to the nasal side considering that the eyes are focused on the bottom. In addition, the distance between the fitting point F and the upper end of the near refractive power reference circle 2 , that is, the progressive zone length is shown. The refractive power of the near part is that the lens 101 is S-6.00D, and the lens 102 is S-2.00D. The addition degree is that both lenses are 2.00D, but the progressive zone length of lens 101 with more negative refractive power at the distance part is 10.38 mm, and the progressive zone length of lens 102 with more positive refractive power at the far part is 12.28 mm, and adding In the case of the same power, the progressive zone length of the lens 101 whose refractive power is more negative (smaller) at the distance portion becomes shorter. The amount of inward deviation of the near portion can also be changed according to the refractive power of the lens, but in this embodiment, the amount of inward deviation is fixed at 2.5 mm for easy understanding of the description.

In Table 1, the refractive power and addition degree of the first dioptric portion of the progressive dioptric power lens group unified according to the refractive index of the same lens material and the same design idea as the lens shown in Figure 1 are shown as parameters, showing the assembly The distance in the vertical direction between the point F and the upper end of the reference circle for near (diopter power measurement point of the second diopter) 2 is taken as an example of the length of the progressive zone length.

[Table 1] Diopter power S(D) of distance part Join degree ADD(D) 1.00 2.00 3.00 +6.00 16.78 17.06 17.34 +5.00 16.30 16.58 16.86 +4.00 15.82 16.10 16.38 +3.00 15.34 15.62 15.90 +2.00 14.86 15.14 15.42 +1.00 14.38 14.66 14.94 0.00 13.91 14.18 14.46 -1.00 13.43 13.71 13.98 -2.00 12.95 13.23 13.51 -3.00 12.48 12.75 13.03 -4.00 11.99 12.28 12.55 -5.00 11.50 11.79 12.08 -6.00 11.00 11.30 11.59 -7.00 10.58 10.80 11.10 -8.00 10.07 10.38 10.60

The refractive powers and additions of the first diopters shown in Table 1 are set every 1D, but even finer than this, for example, every 0.5D is exactly the same.

In the case of the same addition degree, as the distance power becomes more negative (small power), the progressive zone length becomes shorter. In addition, when the refractive power of the distance part is the same, the length of the progressive zone increases with the increase of the addition degree. Furthermore, among lenses with the same refractive power for near use, the progressive zone length becomes shorter when the addition degree is larger. For example, a lens with a refractive power of S+1.00D at the distance part and an addition ADD of 1.00D has a near refractive power of S+2.00D, which is the same near refractive power as a lens with a refractive power of S0.00D at the distance part and an ADD of 2.00D. The length of the progressive zone of the former is 14.38mm, and the length of the progressive zone of the latter is 14.18mm. When the near refractive power is the same, the length of the progressive zone shortens with the increase of the degree of addition.

In the above description, the design of the progressive power lens group without additional astigmatism correction properties was described. However, in general spectacle lenses, in addition to the spherical refractive power, there are often astigmatic refractive powers. In the case of an astigmatic lens, the prism effect of the near portion changes depending on the direction of the astigmatism axis. Therefore, when the astigmatism positive characteristic is added to any one of the refractive surface on the eyeball side or the object side, and the astigmatism refractive power at the measurement position where the refractive power of the first refracting part is measured is not zero, the spherical refractive power and the astigmatism can be combined. In the distance part refractive power synthesized by refractive power, the refractive power component along the direction of the progressive zone, that is, the refractive power in the direction from the assembly point F to the upper end of the addition reference circle 2 is regarded as the distance refractive power, and the progressive refractive power lens is used set of designs. Specifically, it is designed to be an assembly point of a progressive dioptric power lens having a smaller refractive power of the first dioptric part in the vertical direction component of the astigmatism dioptric power between progressive dioptric power lenses having the same addition degree and dioptric power of the first refracting part The distance in the vertical direction between the predetermined position for measuring the addition measurement range of the second refracting part is shorter.

For example, as shown in Figure 5, assuming that the astigmatism axis forms an angle of 45 degrees from the base point on the right side of the horizontal direction to the meridian when observing the optometrist from the front, the astigmatism refractive power of the lens shown in Figure 5(a) is astigmatism The refractive power in the axial direction is -2.00D, the refractive power in the meridian direction perpendicular to the astigmatism axis is -6.00D, and the component in the vertical direction is -4.00D. On the other hand, the astigmatism axis of the lens shown in Figure 5(b) is also located in the direction of 45 degrees of the meridian, the refractive power in the direction of the astigmatism axis is -2.00D, and the refractive power in the direction of the meridian perpendicular to the astigmatism axis is -5.00 D, the refractive power component in the vertical direction is -3.50D. Compared with the refractive power component in the vertical direction of the astigmatism of the lens shown in Figure 5(d), the refractive power component in the vertical direction of the astigmatism of the lens shown in Figure 5(a) is smaller, that is, has a more negative refractive power, Therefore, compared with the lens shown in Figure 5(b), the lens shown in Figure 5(a) has a larger refractive power of the prism at the measurement position Np of the near part, and it is necessary to place the upper end of the near part on the upper side and shorten the progressive belt length.

In addition, for example, since it is practically difficult to design a progressive dioptric power lens group that finely sets the refractive power or addition of the first diopter every 0.1D, the progressive zone length is fixed, for example, within the range of 0.1 to 0.5D. , but in the design of the progressive power lens group, there is no change in the tendency to increase or decrease the length of the progressive zone according to the refractive power of the above-mentioned near portion, that is, the refractive power of the prism.

In addition, in order to reduce the manufacturing cost, it is of course also conceivable to make the progressive zone lengths the same within a certain range of refractive power (for example, the range from S-5.00D to S-8.00D). In this case, if the progressive zone length of the lens having a relatively negative refractive power at the near portion is set to be short over the entire range of refractive power, it is considered to be included in the scope of the present invention.

In addition, in the above description, it is described as: in order to simply express the length of the progressive zone, the distance in the vertical direction between the fitting point and the near refractive power measurement point of the second refracting part is defined as the length of the progressive zone, and the predetermined position is preferably It is the upper end of the addition power measurement range, but the progressive zone length of each progressive power lens is a relative value, so of course, for example, a predetermined position within the addition power measurement range can be used as the near refractive power measurement point Np.

The design method of the progressive dioptric power lens group of the present invention is designed as follows: no matter which progressive dioptric power lens in the progressive dioptric power lens group that is selected as a collection of progressive dioptric power lenses unified by the same design idea, the same lens as the previous lens can be used. Viewing objects in the correct posture can be used as a method of designing lenses for well compensating for the lack of accommodative power caused by presbyopia.

Claims (3)

1. A design method of a progressive refractive power lens group, characterized in that, Regarding the following progressive dioptric power lens group: the progressive dioptric power lens group is a collection of progressive dioptric power lenses, each progressive dioptric power lens has: A second dioptric portion for observing the refractive power of an object located at a short distance, and a progressive portion for gradually changing the refractive power from the first dioptric portion to the second dioptric portion, and the progressive dioptric power lens group satisfies the following conditions : the first diopter with different refractive power can be selected, multiple addition degrees can be selected for the first diopter with the same refractive power, the refractive index of the material is the same, and the design concept of each progressive dioptric power lens is unified , Each progressive power lens is designed as follows: Between progressive dioptric power lenses having the same addition degree, in the side where the refractive power of the first refracting part is smaller, the distance in the vertical direction between the fitting point and the refractive power measurement point of the second refracting part shorter distance, Among the progressive dioptric power lenses having the same dioptric power of the first dioptric section, the one with the larger addition degree has a longer distance in the vertical direction between the fitting point and the dioptric power measurement point of the second dioptric section. . 2. the design method of progressive refractive power lens group as claimed in claim 1, is characterized in that, designs each progressive refractive power lens as follows: In the case where the astigmatic refractive power at the refractive power measurement point of the first refractive part is not zero, Among the progressive dioptric power lenses having the same refractive power as the first dioptric part, and the progressive dioptric power lens whose dioptric power of the first dioptric part is small in the vertical direction component of the astigmatism dioptric power, the assembling point and the The distance in the vertical direction between the refractive power measurement points of the second refractive part is shorter. 3. the design method of progressive refractive power lens group as claimed in claim 1 or 2, is characterized in that, Set the distance in the vertical direction between the assembly point and the refractive power measurement point of the second refractor as the distance in the vertical direction from the following first transition position to the second transition position, the first The transition position is: on the principal meridian, the transition position from the region where the refractive power of the first refracting part is substantially fixed to the region where the refractive power changes, and the second transition position is: between the progressive part and the second Between the refractive parts, the transition from the refractive power change area to the near area where the refractive power is approximately constant.

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