Progressive refractive power lens series

Abstract

To provide a progressive refractive power lens series which more efficiently meets the need for variation and the like of power at a fitting point, and with which costs are further reduced.SOLUTION: Provided is a progressive refractive power lens series consisting of a plurality of progressive refractive power lenses 1 that include: a near sight part 2 for viewing an object (a near view) located at a near distance; a far sight part 4 for viewing an object (a distant view) located at a distance which is more distant than the near distance; and an intermediate part 6 which is a portion between the far sight part 4 and the near sight part 2, and where power varies continuously from the far sight part 4 to the near sight part 2. In each of the progressive refractive power lenses 1, a prescription far sight power related to the far sight part 4 is common, and a near sight power related to the near sight part 2 is common. In addition, fitting points FP are arranged at the intermediate part 6, and power (a specific power) at the fitting points FP is mutually different and set based on viewing distances obtained by converting each specific power (so that the viewing distances are evenly spaced).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a series of progressive refractive power lenses, which is a set of multiple progressive refractive power lenses. [Background technology]

[0002] A progressive refractive power lens has a distance vision portion located at the top of the lens when worn, which is suitable for relatively distant vision; a near vision portion located at the bottom of the lens when worn, which is suitable for relatively near vision; and a progressive portion located between them, in which the power increases progressively from the distance vision portion to the near vision portion. Generally, in the handling of orders and deliveries related to progressive power lenses, the distance prescription power, which is the power at a reference point within the distance vision section, and the addition power, which is the addition power to the distance prescription power at a reference point within the near vision section, are used. Lens manufacturers and other lens handlers (lens orderers, lens shippers) send progressive power lenses that match the distance prescription power and addition power to the lens orderer (lens recipient). The frequency distribution in the progressive portion is basically set arbitrarily as long as it satisfies the prescription frequency for distance use and the prescription frequency related to the order.

[0003] As a series of progressive refractive power lenses, those described in Japanese Patent Publication No. 6604959 (Patent Document 1) are known. This series (progressive power lens group) includes multiple progressive power lenses in which the near-vision power in the near-vision portion (near-vision area) is common, the power in a predetermined portion (e.g., fitting point) of the progressive portion (intermediate area) is common and corresponds to a preset target distance, and the power in the far-vision portion (specific area) differs from one another. The fitting point is the reference point (pupil position) when wearing contact lenses, and is also called the eye point. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 6604959 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the above-mentioned progressive power lens series, the near vision prescription and the prescription at the designated position (fitting point) within the progressive section are common, but the distance vision prescription differs from one another. Therefore, it is difficult to handle these lenses using the same methods as general progressive power lenses, which focus on distance vision prescriptions and corresponding add powers (add percentages). Consequently, it is difficult to use existing progressive power lens ordering and receiving systems as they are, and supporting this series incurs additional costs. Therefore, the main objective of the present invention is to provide a series of progressive refractive power lenses that can more efficiently meet needs such as variations in prescription at fitting points while reducing costs. [Means for solving the problem]

[0006] To achieve the above objective, the invention described in claim 1 is a progressive power lens series comprising a plurality of progressive power lenses, each having a near-vision portion for viewing objects at a close distance, a far-vision portion for viewing objects at a distance greater than the near distance, and an intermediate portion between the far-vision portion and the near-vision portion, wherein the power changes continuously from the far-vision portion to the near-vision portion, and each of the progressive power lenses has a common far-vision power, and a common near-vision power, and furthermore, a fitting point is located in the intermediate portion, and the specific powers at the fitting point are different from each other, and are set based on the viewing distance converted from each of the specific powers. Each of the aforementioned specific degrees is set such that the viewing distances are equally spaced. It is characterized by being present. In order to achieve the above objective, Claim 2The invention described herein is a progressive power lens series comprising a plurality of progressive power lenses, each having a near-vision portion for viewing objects at a close distance, a far-vision portion for viewing objects at a distance greater than the near distance, and an intermediate portion between the far-vision portion and the near-vision portion, wherein the power changes continuously from the far-vision portion to the near-vision portion, and each of the progressive power lenses has a common far-vision power, and a common first add power, which is the power added to the far-vision power in the near-vision portion, and furthermore, a fitting point is located in the intermediate portion, and the first specific add power, which is the power added to the far-vision power at the fitting point, is different from each other, and is set based on the viewing distance converted from each of the first specific add powers. Each of the first specified addition powers is set such that the viewing distances are equally spaced. It is characterized by being present. In order to achieve the above objective, Claim 3 The invention described herein is a progressive power lens series comprising a plurality of progressive power lenses, each having a near-vision portion for viewing objects at a close distance, a far-vision portion for viewing objects at a distance greater than the near distance, and an intermediate portion between the far-vision portion and the near-vision portion, wherein the power changes continuously from the far-vision portion to the near-vision portion, and each of the progressive power lenses has a common near-vision power, and a common second-add power, which is the power added to the near-vision power in the far-vision portion, and furthermore, a fitting point is located in the intermediate portion, and the second-specific add power, which is the power added to the near-vision power at the fitting point, is different from each other, and is set based on the viewing distance converted from each of the second-specific add powers. Each of the second specified addition powers is set such that the viewing distances are equally spaced. It is characterized by being present. Claim 4The invention described above is characterized in that, in each of the progressive power lenses, the position of the fitting point with respect to the geometric center is common, and the shape of at least one of the front and rear surfaces that satisfy the near vision portion, the far vision portion, and the respective powers at the fitting point are different from each other. Claim 5 The invention described above is characterized in that, in each of the progressive power lenses, the shapes of the front and rear surfaces are common in such a way that they satisfy the respective powers of the near and far vision portions, and the positions of the fitting points relative to the geometric center are different from each other in such a way that they satisfy the powers at the fitting points. [Effects of the Invention]

[0007] The main effect of the present invention is to provide a series of progressive refractive power lenses that can more efficiently meet needs such as variations in prescription at fitting points while reducing costs. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic front view of a progressive power lens belonging to the progressive power lens series according to the first embodiment of the present invention. [Figure 2] This graph is used to determine the variation of progressive lenses within a series of progressive lenses in a first embodiment of the present invention. [Figure 3] This graph shows the relationship between the vertical position Y [mm] (horizontal axis) and the add power ADD [D] (vertical axis) on a progressive power lens in the first design example of the first form. [Figure 4] This graph shows the relationship between the vertical position Y [mm] (horizontal axis) and the add power ADD [D] (vertical axis) on a progressive power lens in the second design example of the first form. [Figure 5] This is a schematic front view showing the layout of various reference points on a progressive power lens in the second design example of the first embodiment. [Figure 6]A graph showing the relationship between the vertical position Y [mm] (horizontal axis) and the addition power ADD [D] on the progressive refractive power lens according to the first design example in the second form.

Embodiments for Carrying out the Invention

[0009] Hereinafter, examples of embodiments according to the present invention will be described as appropriate based on the drawings. Note that the embodiments of the present invention are not limited to these examples.

[0010] [First Form] As shown in FIG. 1, the progressive refractive power lens 1 belonging to the progressive refractive power lens series according to the first form of the present invention is circular (round lens) when viewed from the front of the wearer (user) with respect to the posture of the lens at the time of wearing. The progressive refractive power lens 1 is different for the right eye and the left eye, and the right-eye lens is shown in FIG. 1. In FIG. 1, the upper side is the upper side at the time of wearing, and the right side is the nasal side of the wearer. After the power and the like are adjusted in the round lens, the progressive refractive power lens 1 is subjected to a spherical shaping process according to the shape of the spectacle frame, and then is framed in the spectacle frame. The wearer actually wears the spectacle frame in which the progressive refractive power lens 1 after the spherical shaping process is framed. Note that the progressive refractive power lens 1 before the spherical shaping process may not be circular. Also, the progressive refractive power lenses 1 for the right eye and the left eye may be the same as each other. The progressive refractive power lens 1 has a near vision portion 2, a distance vision portion 4, and an intermediate portion 6.

[0011] The near vision portion 2 is disposed at the lower part of the progressive refractive power lens 1. The near vision portion 2 has a refractive power corresponding to a near view. The near vision portion 2 is a portion for viewing an object at a near distance. The distance vision portion 4 is disposed at the upper part of the progressive refractive power lens 1. The distance vision portion 4 has a refractive power corresponding to a distance view. The distance vision portion 4 is a portion for viewing an object at a distance farther than the near distance in the near vision portion 2. The distance view and the near view, as well as the distance vision and the near vision, are all relative. The intermediate portion 6 is disposed between the near-vision portion 2 and the distance-vision portion 4. The diopter of the intermediate portion 6 continuously changes between the near-vision portion 2 and the distance-vision portion 4. The diopter of the intermediate portion 6 progresses from the distance-vision portion 4 toward the near-vision portion 2.

[0012] The progressive refractive power lens 1 has various reference points. The circular center of the progressive refractive power lens 1 is the geometric center GC. In addition, the progressive refractive power lens 1 has a fitting point FP. The fitting point FP is a point assuming the correspondence with the position of the wearer's pupil as viewed from the front side during wearing. Here, the fitting point FP is, in principle, a point 2 mm above the geometric center GC, and is a point where the position based on the geometric center GC or the like can be changed depending on the design. Furthermore, the progressive refractive power lens 1 has a distance reference point FV. The distance reference point FV is disposed within the distance-vision portion 4, and here is the lower side portion of the distance-vision portion 4, and is a point 16 mm above the geometric center GC. The distance reference point FV is a reference point for measuring the distance diopter of the progressive refractive power lens 1. The refractive power at the distance reference point FV is set based on, for example, the distance diopter (prescribed distance diopter) specified by the prescription. Still further, the progressive refractive power lens 1 has a near reference point NV. The near reference point NV is disposed within the near-vision portion 2, and here is the upper side portion of the near-vision portion 2, and is a point 12 mm below and further 2.3 mm nasal to the geometric center GC. The near reference point NV is a reference point for measuring the near diopter of the progressive refractive power lens 1. The refractive power at the near reference point NV is set based on, for example, the prescribed distance diopter and the added diopter (prescribed added diopter) specified by the prescription. The fitting point FP is between the distance reference point FV and the near reference point NV, and has a predetermined added diopter with respect to the prescribed distance diopter. The absolute value of the added diopter at the fitting point FP is smaller than the absolute value of the prescribed added diopter at the near reference point NV. Note that the arrangement (layout), presence or absence of setting, etc. of various reference points are not limited to those described above.

[0013] Generally, progressive lenses are broadly classified into three categories according to their intended use: distance progressive, intermediate-near progressive, and near-near progressive. The progressive refractive power lens 1, designed for near- and far-field vision, is optimized for viewing distant objects near the fitting point (FP). The intermediate-near progressive lens 1 is designed to be suitable for viewing intermediate distances near the fitting point FP. The near-to-near progressive lens 1 is designed to be suitable for viewing close distances near the fitting point (FP). For example, the add-on ratio at fitting point FP for a progressive refractive lens 1 with distance-to-near vision is 0% or more and less than 15%, the add-on ratio at fitting point FP for a progressive refractive lens 1 with intermediate-to-near vision is 15% or more and less than 50%, and the add-on ratio at fitting point FP for a progressive refractive lens 1 with near-near vision is 50% or more and 70% or less. Here, the enrollment rate is the ratio of the enrollment rate of the point of interest (e.g., fitting point FP) to the prescription enrollment rate, i.e., "enrollment rate = (enrollment rate of that point / prescription enrollment rate) × 100" [%]. The first form relates to the progression from the middle to the near.

[0014] The visual perception at the fitting point (FP) is relatively important because it represents the visual perception at the pupil's position during wear. Furthermore, individual differences exist even among wearers with the same prescribed distance power and add power. Therefore, there is a need to accommodate these individual differences in visual perception as much as possible in progressive lenses. Thus, it is useful to have variations in the progressive lens series where lenses have the same prescribed distance power and add power, but with different powers at the fitting point (FP). Figure 2 is a graph relating to the determination of variations in the first form. The horizontal axis of this graph represents the add-on ratio at the fitting point FP. The vertical axis of this graph represents the viewing distance [cm] at the fitting point FP. Here, the viewing distance is the distance at which the image is in focus, and the distance at which the wearer wants to see. Furthermore, to reduce complexity, it is assumed that the wearer's accommodative power is 0.00D (diopter). The relationship between the subscription rate and viewing distance is such that the viewing distance always decreases as the subscription rate increases, and the degree of this decrease (the slope of the tangent to the curve) decreases as the subscription rate increases. The relationship between power and viewing distance is similar to that between the subscription rate and viewing distance. In the first form, a group of add ratios is determined such that the viewing distances obtained by converting the add ratio at the fitting point FP are equally divided, and a progressive power lens series having this group of add ratios as variations is determined. Furthermore, in the first form, the prescribed distance power (distance prescription) for each progressive lens is the same. Also, the prescribed add power (first add power) for each progressive lens is the same, and therefore the near power for each progressive lens is the same.

[0015] In the first form, the lower and upper limits of the add-on ratio at the fitting point FP for the progressive power lens group 1 belonging to the progressive power lens series are set to 15% and 50%, respectively. Furthermore, the number of progressive refractive power lenses belonging to the progressive refractive power lens series is set at 8. Furthermore, in the first form, the prescription enrollment frequency is 2.00D, but even if the prescription enrollment frequency is a different value, the group of enrollment rates derived will be the same.

[0016] The variations under these conditions are shown in Table 1 below.

[0017] [Table 1]

[0018] Specifically, in the progressive power lens 1 of design type 1, the add percentage at fitting point FP is 15.0%, which is the lower limit of the series, the power is 0.30D, and the viewing distance is 333.33cm. Furthermore, in the progressive power lens 1 of design type 8, the add ratio at fitting point FP is 50.0%, which is the upper limit of the series, the power is 1.00D, and the viewing distance is 100.00cm. Furthermore, in design types 1 through 8, the viewing distances are equally spaced (33.33 steps) relative to adjacent design types. Furthermore, for design types 1 through 8, the interval between the subscription rates for the next design type increases as the design type number increases. For example, the difference in subscription rates between design types 1 and 2 is 0.03, while the difference between design types 7 and 8 is 0.25.

[0019] If, unlike the first form, a group of progressive power lenses 1 in which the add ratios at fitting point FP are equally spaced were to be designated as a progressive power lens series, then in the region with a particularly large add ratio (the region on the upper limit of the add ratio), there would be many progressive power lenses 1 in which the viewing distance does not change much and are difficult for the wearer to distinguish, resulting in poor efficiency. Furthermore, if the number of progressive power lenses 1 in a series of progressive power lenses is reduced (for example, to about 9 or fewer), the spacing between progressive power lenses 1 in the range of relatively large viewing distances becomes larger, resulting in relatively insufficient coverage in the range of large viewing distances. In such cases, in the first form, since the viewing distances at the fitting point FP are equally spaced, the variation can be dense in areas where the change in viewing distance is large, and sparse in areas where the change in viewing distance is small, thus efficiently covering a range of subscription rates.

[0020] In the first form, at least one of the upper and lower limits of the add-on ratio at the fitting point FP, and the number of progressive lenses 1 (number of divisions) in the progressive lens series can be arbitrarily changed. That is, let n be the design type number (design type n, where n is a natural number and its maximum value is the number of partitions n). max (The smaller n is, the lower the limit of the enrollment rate at fitting point FP), and the enrollment rate at fitting point FP for number n is A n Let A be the lower limit and upper limit of the membership rate. min ,A max Let L be the viewing distance at fitting point FP at number n. n Let P be the prescription add power and δ be the step (increment in viewing distance). Then, the add ratio A at fitting point FP. n The answer can be found using the following equations (1) to (3).

[0021]

number

[0022] The distribution of the subscription rate in the intermediate section 6 in the first form can be designed in various ways while satisfying the conditions set for each design type (number n). Two design examples are given below.

[0023] The first design example concerns the case where the positions of the distance reference point FV, fitting point FP, and near reference point NV relative to the geometric center GC in the group of progressive power lenses 1 are kept constant. Note that, for all progressive power lenses 1, the refractive index is set to 1.60, the vertical distance between the distance reference point FV and the near reference point NV (progressive zone length) is 21 mm, the prescribed distance power is S0.00, and the prescribed add power is 2.00. Even if these values ​​change, the design can be carried out in the same manner as described below. Figure 3 is a graph showing the relationship between the vertical position Y [mm] (horizontal axis) and the add power ADD [D] (vertical axis) on the progressive power lens 1 according to the first design example. Position Y is set to 0 at the geometric center GC and takes positive values ​​(left side in the graph of Figure 3) above the geometric center GC. Also, the absolute value of position Y increases as you move away from the geometric center GC. Figure 3 shows three types of progressive refractive power lenses 1 with design type numbers n=1, 5, and 7.

[0024] In the progressive lens 1 with n=1, the distribution of add power in the vertical direction in the intermediate section 6 is as follows: at position Y=16 corresponding to the distance reference point FV, the add power ADD=0; at position Y=2 corresponding to the fitting point FP, the add power ADD=0.30 (add ratio 15.0%, 15.0% add); and at position Y=-12 corresponding to the near reference point NV, the add power ADD is close to 2.00, with a smooth transition between these positions. The reason why the add power ADD is not exactly 2.00 at position Y=-12 corresponding to the near reference point NV is due to the inclusion of transmitted light correction. In the progressive refractive power lens 1 with n=5, the distribution of add power in the vertical direction in the intermediate section 6 is such that the add power ADD=0 at position Y=16 corresponding to the distance reference point FV, the add power ADD=0.50 (addition ratio 25.0%, 25.0% add) at position Y=2 corresponding to the fitting point FP, and the add power ADD is close to 2.00 at position Y=-12 corresponding to the near reference point NV, with the add power ADD smoothly connected between these points. In the progressive refractive power lens 1 with n=7, the distribution of add power in the vertical direction in the intermediate section 6 is such that the add power ADD=0 at position Y=16 corresponding to the distance reference point FV, the add power ADD=0.75 (addition ratio 37.5%, 37.5% add) at position Y=2 corresponding to the fitting point FP, and the add power ADD=2.00 at position Y=-12 corresponding to the near reference point NV, with the add power ADD smoothly connected between these points.

[0025] In these progressive lenses 1, the add power ADD at the position corresponding to the distance reference point FV is consistently 0, and the add power ADD at the position corresponding to the near reference point NV is consistently 2.00 (prescription add power). Furthermore, variations are provided in the add power ADD at the fitting point FP in these progressive lenses 1 (ADD = 0.30, 0.50, 0.75). In these progressive power lenses 1, the shape of at least one of the front surface (the surface facing the object when worn) and the back surface (the surface facing the eye when worn) of each intermediate section 6 is designed to have a corresponding distribution of add power ADD. Similarly, progressive refractive power lenses 1 with other numbers (n=2~4,6,8) are designed accordingly.

[0026] The second design example relates to the case where the shapes of the front and rear surfaces of the intermediate section 6 in the group of progressive power lenses 1 are kept constant. Similar to the first design example, the refractive index is set to 1.60, the vertical distance between the distance reference point FV and the near reference point NV (progressive zone length) is 21 mm, the prescribed distance power is S0.00, and the prescribed add power is 2.00 for all progressive power lenses 1. Even if these values ​​change, the design can be carried out in the same manner as described below. Figure 4 is a graph showing the relationship between the vertical position Y [mm] (horizontal axis) and the add power ADD [D] (vertical axis) on the progressive power lens 1 in the second design example. In the second design example, all progressive power lenses 1 have the same add power ADD distribution as the progressive power lens 1 (25.0% add) with design type number n=5 in the first design example. In the second design example, variations can be obtained by changing the position of the fitting point FP (relative to the geometric center GC).

[0027] Figure 5 shows the layout of various reference points for three types of progressive refractive power lenses 1 with design type numbers n=1, 5, and 7. For progressive lens 1 with n=1, we would like the add power ADD=0.30 at fitting point FP. In the distribution shown in Figure 4, the position where the add power ADD≈0.30 is at position Y=5, so fitting point FP is set to a point 5mm above the geometric center GC (fitting point FP1). Strictly speaking, the add power ADD=0.29 at fitting point FP1, but from the perspective of improving handling, the fitting point FP1 for progressive lens 1 with n=1 is specified as a point where the distance from the geometric center GC, etc., is a round number such as an integer. Alternatively, prioritizing accuracy over handling, the position Y where the add power ADD=0.30 is obtained may be determined more precisely. For progressive lens 1 with n=5, we would like the add power ADD=0.50 at fitting point FP. However, in the distribution shown in Figure 4, the position where the add power ADD=0.50 occurs is Y=2. Therefore, fitting point FP is set to a point 2mm above the geometric center GC (fitting point FP5). For progressive lens 1 with n=7, we would like the add power ADD=0.75 at fitting point FP. In the distribution shown in Figure 4, the position where the add power ADD ≈ 0.75 is at position Y = -1.0, so fitting point FP is set to a point 1 mm below the geometric center GC (fitting point FP7). Strictly speaking, the add power ADD=0.78 at fitting point FP7, but from the perspective of improving handling, a point where the distance from the geometric center GC etc. is a round number is designated as fitting point FP7 for progressive lens 1 with n=7. Alternatively, prioritizing accuracy over handling, the position Y where the add power ADD=0.75 is obtained may be determined more precisely.

[0028] In these progressive lenses 1, the add power ADD at the position corresponding to the distance reference point FV is consistently 0, and the add power ADD at the position corresponding to the near reference point NV is consistently 2.00 (prescription add power). Furthermore, variations are provided in the add power ADD at the positions corresponding to fitting points FP1 to FP7 (ADD ≈ 0.30, 0.50, 0.75). In these progressive power lenses 1, the position of fitting point FP is designed such that each fitting point FP1 to FP7 has an add power ADD corresponding to the number n. Similarly, progressive refractive power lenses 1 with other numbers (n=2~4,6,8) are designed accordingly.

[0029] In the first embodiment, the progressive power lens series consists of multiple progressive power lenses 1, each having a near-vision section 2 for viewing objects at a close distance (foreground), a far-vision section 4 for viewing objects at a distance greater than the near-vision section (far-view), and an intermediate section 6 between the far-vision section 4 and the near-vision section 2, where the power changes continuously from the far-vision section 4 to the near-vision section 2. In each progressive power lens 1, the prescribed far-vision power, which is the power in the far-vision section 4, is common, as is the prescribed add-on power, which is the power added to the prescribed far-vision power in the near-vision section 2. Furthermore, a fitting point FP is placed in the intermediate section 6, and the add ratios for each add-on power (first specific add-on power) relative to the prescribed far-vision power at the fitting point FP are different from each other and are set based on the viewing distance converted from each add-on ratio (represented by the first specific add-on power). Therefore, a series of progressive power lenses is provided that can meet the needs for variations in prescription at the fitting point (FP) more efficiently and at a lower cost.

[0030] Furthermore, the first specific addition power is set so that the viewing distances are equally spaced. Therefore, it is possible to more efficiently meet the needs for variations in prescription at the fitting point (FP). Furthermore, the viewing distances used to set the first specific add frequency do not need to be perfectly identical. For example, each interval may be partially or entirely discrete, as long as it falls within the upper and lower limits obtained by applying a value of ±20% to the average value of all intervals. Alternatively, instead of ±20%, it may be ±10%, ±5%, or ±2%.

[0031] Furthermore, the near vision power is the prescription distance power plus the prescription add power, and the power at the fitting point FP is the prescription distance power plus the first specific add power. In the first form, the progressive power lens series consists of multiple progressive power lenses 1 having a near vision section 2 for viewing objects at close distances (foreground), a distance vision section 4 for viewing objects at distances greater than that near distance (background), and an intermediate section 6 between the distance vision section 4 and the near vision section 2, where the power changes continuously from the distance vision section 4 to the near vision section 2. In each progressive power lens 1, the prescription distance power, which is the power in the distance vision section 4, and the near vision power, which is the power in the near vision section 2, are common. In addition, a fitting point FP is located in the intermediate section 6, and the specific powers, which are the powers at the fitting point FP, are different from each other and are set based on the viewing distance converted from each specific power (so that the viewing distances are equally spaced). Therefore, a series of progressive power lenses is provided that can meet the needs for variations in prescription at the fitting point (FP) more efficiently and at a lower cost.

[0032] Furthermore, in the first design example of the first embodiment, the position of the fitting point FP relative to the geometric center GC is common in each progressive power lens 1, and the shape of at least one of the front and rear surfaces that satisfy each power (prescription add power, prescription distance power, specific power) at the near vision portion 2, the far vision portion 4, and the fitting point FP is different from each other. Therefore, a series of progressive power lenses with even better handling of the fitting point (FP) is provided.

[0033] Further, in the second design example of the first embodiment, in each progressive refractive power lens 1, the shapes of the front surface and the rear surface are common in a state that satisfies the respective powers (prescribed addition power, prescribed distance power) of the near vision portion 2 and the distance vision portion 4, and the positions of the fitting points FP based on the geometric center GC are different from each other so as to satisfy the power. Therefore, by using progressive refractive power lenses 1 having the same shape, a progressive refractive power lens series having more excellent cost performance is provided.

[0034] [Second Embodiment] The progressive refractive power lens series according to the second embodiment of the present invention is the same as the first embodiment except that it is related to near-near progression instead of intermediate-near progression. Also in the second embodiment, as in the first embodiment, it is assumed that the accommodative power of the wearer is 0.00D. Even in near-near progression, the above formulas (1) to (3) hold. In the second embodiment, the lower limit value A min , upper limit value A max of the addition ratio at the fitting point FP in the group of progressive refractive power lenses 1 belonging to the progressive refractive power lens series are 50% and 70% in this order. Also, the number of divisions n max is 5. The distance vision reference point FV in the second embodiment is 14 mm above the geometric center GC, the fitting point FP is, in principle, 4 mm above the geometric center GC, and the near vision reference point NV is 2 mm nasalward and 8 mm below the geometric center GC. Incidentally, also in the second embodiment, various values can be arbitrarily changed. Furthermore, in the second form, the power at the near reference point NV (prescribed near power) and the corresponding add power at the far reference point FV (prescribed add power) are prescribed and specified. The prescribed near power is prescribed based on the expected appearance in the near section 2. The appearance in the near section 2 depends on the finite distance (near working distance) that the wearer desires to see best. Here, the prescribed near power is S0.00D and the prescribed add power is -1.50D. If the prescribed near power is S0.00D, for example, it becomes a near-near progressive lens suitable for a wearer who can see at infinity with correction using a -2.00D lens and whose desired near working distance is 50cm (=2.00D) (a wearer for whom a prescribed far power of S-2.00D and a prescribed add power of ADD2.00D are suitable for progressive lenses). When the near working distance is 50 cm, the viewing distance for distant objects (distance part 4) is 50 - (-1 / 1.5) = 116.67 cm, given that the prescribed add power is -1.50. Furthermore, for all progressive power lenses 1, the refractive index is set to 1.60, and the vertical distance between the distance reference point FV and the near reference point NV (progressive zone length) is set to 21 mm. Even if these values ​​change, the design can be carried out in the same manner as described below. Similarly, even if the near working distance changes to 40 cm, the design can be carried out in the same manner as described below.

[0035] The variations under such conditions are shown in Table 2 below.

[0036] [Table 2]

[0037] Specifically, in the n=1 progressive power lens 1 relating to the second form, the add ratio at fitting point FP is 50.0%, which is the lower limit of the series, the power is -0.75D, the reciprocal of the power (1 / power) is -133.33, and the viewing distance is 50 - (-133.33) = 183.33 cm, which is calculated as "near working distance - (1 / power). Furthermore, regarding the second form, n=5=n maxIn progressive power lens 1, the add percentage at fitting point FP is 70.0%, which is the upper limit of the series, the power is -1.05D, the reciprocal of the power is -95.24, and the viewing distance is 50 - (-95.24) = 145.24 cm. Furthermore, in the second form of progressive refractive power lens 1 with n=1 to 5, the viewing distances are equally spaced (approximately 9.52 steps, see equation (3)) for adjacent design types. Furthermore, in progressive refractive power lens 1 with n=1 to 5, the interval between powers for the next design type increases as the design type number n increases. For example, the absolute value of the power difference between design types 1 and 2 is 0.06, while the absolute value of the power difference between design types 4 and 5 is 0.10.

[0038] If, unlike the second form, a group of progressive power lenses 1 in which the add ratios at fitting point FP are equally spaced were to be designated as a progressive power lens series, then in the region with particularly large add ratios, there would be many progressive power lenses 1 in which the viewing distance does not change much and are difficult for the wearer to distinguish, resulting in poor efficiency. Furthermore, if the number of progressive power lenses 1 in a series of progressive power lenses is reduced, the distance between progressive power lenses 1 in the range of relatively large viewing distances becomes larger, resulting in relatively insufficient coverage in that range. In such cases, the second form allows for dense variation in areas with large changes in viewing distance and sparse variation in areas with small changes in viewing distance, thus efficiently covering a range of subscription rates.

[0039] The distribution of the subscription rate in the intermediate section 6 in the second form can be designed in various ways while satisfying the conditions set for each design type (number n), and, as with the first form, it can also be designed using the first and second design examples.

[0040] In the second form, when the first design example is used, the three design types n=1, 3, and 4 are designed as shown in Figure 6, with the same add frequency ADD=-1.50 at the far-field reference point FV, the same add frequency ADD=0.00 at the near-field reference point NV, and different add frequencies ADD=-0.75, -0.88, and -0.95 at the fitting point FP.

[0041] In other words, in the progressive refractive power lens 1 with n=1, the distribution of the add power in the vertical direction in the intermediate section 6 is such that the add power ADD = -1.50 at position Y=14 corresponding to the distance reference point FV, the add power ADD = -0.75 (addition ratio 50.0%, 50.0% add) at position Y=4 corresponding to the fitting point FP, and the add power ADD = near 0.00 at position Y=-8 corresponding to the near reference point NV, with the add power ADD between these points smoothly connected. Furthermore, in the progressive refractive power lens 1 with n=3, the distribution of add power in the vertical direction in the intermediate section 6 is such that at position Y=14 corresponding to the distance reference point FV, the add power ADD=-1.50, at position Y=4 corresponding to the fitting point FP, the add power ADD=-0.88 (addition ratio 58.3%, 58.3% add), and at position Y=-8 corresponding to the near reference point NV, the add power ADD is close to 0.00, with the add power ADD between these points smoothly connected. Furthermore, in the progressive refractive power lens 1 with n=4, the distribution of add power in the vertical direction in the intermediate section 6 is such that at position Y=14 corresponding to the distance reference point FV, the add power ADD=-1.50, at position Y=4 corresponding to the fitting point FP, the add power ADD=-0.95 (addition ratio 63.6%, 63.6% add), and at position Y=-8 corresponding to the near reference point NV, the add power ADD is close to 0.00, with a smooth transition between these points. Similarly, progressive refractive power lenses 1 with other numbers (n=2~4,6,8) are designed accordingly.

[0042] In these progressive power lenses 1, the shape of at least one of the front and rear surfaces of each intermediate section 6 is designed to have a corresponding distribution of add power ADD.

[0043] In the second form, the progressive power lens series consists of multiple progressive power lenses 1, each having a near-vision section 2 for viewing objects at a close distance (foreground), a far-vision section 4 for viewing objects at a distance greater than the near-vision section (far-view), and an intermediate section 6 between the far-vision section 4 and the near-vision section 2, where the power changes continuously from the far-vision section 4 to the near-vision section 2. In each progressive power lens 1, the prescribed near-vision power, which is the power in the near-vision section 2, is common, as is the prescribed add-on power, which is the power added to the prescribed near-vision power in the far-vision section 4. Furthermore, a fitting point FP is placed in the intermediate section 6, and the add ratios for each add-on power (second specific add-on power) relative to the prescribed near-vision power at the fitting point FP are different from each other, and are set based on the viewing distance converted from each add-on ratio (the second specific add-on power) (so that the viewing distances are equally spaced). Therefore, a series of progressive power lenses is provided that can meet the needs for variations in prescription at the fitting point (FP) more efficiently and at a lower cost.

[0044] Furthermore, the near power is the prescription near power plus the prescription add power, and the power at the fitting point FP is the prescription near power plus the second specific add power. In the first form, the progressive power lens series consists of multiple progressive power lenses 1 having a near power section 2 for viewing objects at a close distance (foreground), a far power section 4 for viewing objects at a distance greater than that near distance (far background), and an intermediate section 6 between the far power section 4 and the near power section 2, where the power changes continuously from the far power section 4 to the near power section 2. In each progressive power lens 1, the prescription near power, which is the power in the near power section 2, and the far power, which is the power in the far power section 4, are common. In addition, a fitting point FP is located in the intermediate section 6, and the specific powers, which are the powers at the fitting point FP, are different from each other and are set based on the viewing distance converted from each specific power (so that the viewing distances are equally spaced). Therefore, a series of progressive power lenses is provided that can meet the needs for variations in prescription at the fitting point (FP) more efficiently and at a lower cost. [Explanation of symbols]

[0045] 1. Progressive refractive power lens, 2. Near vision section, 4. Far vision section, 6. Intermediate section, FP. Fitting point.

Claims

1. A close-up section for viewing objects at a nearby distance, A distance viewing unit for viewing objects at a distance greater than the aforementioned near distance, The portion between the distance vision section and the near vision section, comprising an intermediate section in which the frequency changes continuously from the distance vision section to the near vision section, A series of progressive refractive lenses comprising multiple progressive refractive lenses having, In each of the aforementioned progressive refractive power lenses, The distance vision prescription, which is the power in the aforementioned distance vision section, is the same, The near-vision prescription, which is the prescription for the near-vision part, is the same for all. Furthermore, fitting points are positioned in the intermediate section, and the specific powers at these fitting points are all different from each other, and are set based on the viewing distance converted from each of these specific powers. Each of the aforementioned specific degrees is set so that the viewing distances are equally spaced. A series of progressive refractive power lenses characterized by the following features.

2. A close-up section for viewing objects at a nearby distance, A distance viewing unit for viewing objects at a distance greater than the aforementioned near distance, The portion between the distance vision section and the near vision section, comprising an intermediate section in which the frequency changes continuously from the distance vision section to the near vision section, A series of progressive refractive lenses comprising multiple progressive refractive lenses having, In each of the aforementioned progressive refractive power lenses, The distance vision prescription, which is the power in the aforementioned distance vision section, is the same, In the near-vision portion, the first addition power, which is the power added to the far-vision power, is common to all of the above. Furthermore, fitting points are located in the intermediate portion, and the first specific add-on powers, which are the powers added to the distance power at the fitting points, are different from each other and are set based on the viewing distance converted for each of the first specific add-on powers. Each of the first specified addition powers is set such that the viewing distances are equally spaced. A series of progressive refractive power lenses characterized by the following features.

3. A close-up section for viewing objects at a nearby distance, A distance viewing unit for viewing objects at a distance greater than the aforementioned near distance, The portion between the distance vision section and the near vision section, comprising an intermediate section in which the frequency changes continuously from the distance vision section to the near vision section, A series of progressive refractive lenses comprising multiple progressive refractive lenses having, In each of the aforementioned progressive refractive power lenses, The near-vision prescription, which is the prescription for the near-vision part, is the same, In the distance vision section, the second addition power, which is the power added to the near vision power, is common to all of the above. Furthermore, fitting points are located in the intermediate section, and the second specific add-on powers, which are powers added to the near-vision power at the fitting points, are different from each other and are set based on the viewing distance converted for each of the second specific add-on powers. Each of the second specified addition powers is set such that the viewing distances are equally spaced. A series of progressive refractive power lenses characterized by the following features.

4. In each of the aforementioned progressive refractive power lenses, The positions of the fitting points relative to the geometric center are common. The shapes of the near-vision section, the far-vision section, and at least one of the front and rear surfaces that satisfy each degree at the fitting point are different from each other. A series of progressive refractive power lenses according to any one of claims 1 to 3.

5. In each of the aforementioned progressive refractive power lenses, The front and rear shapes are common in that they satisfy the respective power levels of the near-vision and far-vision sections. The positions of the fitting points relative to the geometric center are different from each other so as to satisfy the degrees at the fitting points. A series of progressive refractive power lenses according to any one of claims 1 to 3.

Images