Design method for single-focus aspherical spectacle lenses and manufacturing method for single-focus aspherical spectacle lenses

Abstract

Within the framework of single-vision eyeglass lenses, the distance to the object in the wearer's line of sight is taken into account, ensuring that the object at that distance can be clearly and reliably seen. [Solution] A method for designing a single-focus spectacle lens, in which a prescription value corresponding to only one object distance D0 is set, comprising: an object distance setting step of setting an object distance Dn from the wearer to a predetermined object at each position in the planar xy plane of the optical surface of the spectacle lens when the wearer's line of sight passes through that position when viewing a predetermined object, and ensuring that there are three or more types of object distances Dn in the planar xy plane, including the object distance D0; an aspheric coefficient calculation step of calculating an aspheric coefficient corresponding to each object distance Dn at each of the set positions; and a z-axis coordinate transformation step of converting each calculated aspheric coefficient into a z-axis coordinate indicating the height for each position, is provided as a method for designing a single-focus aspheric spectacle lens and related technologies.

Description

Technical Field

[0001] The present invention relates to a method for designing a single-focus aspherical spectacle lens and a method for manufacturing a single-focus aspherical spectacle lens.

Background Art

[0002] There was room for improvement in the appearance of spectacle lenses for myopia correction by aspherizing the surface on the object side or the surface on the eyeball side of the spectacle lens for myopia correction (for example, pages 2, lower left column, line 4 - page 3, upper right column, line 12 of Patent Document 1). On the other hand, in the technique described in Patent Document 1, a special aspherical shape is adopted for the surface on the object side, and while improving the appearance of the spectacle lens for myopia correction, a spectacle lens excellent in optical performance is provided (for example, pages 3, upper right column, line 13 - lower left column, line 10 of Patent Document 1).

[0003] The single-focus aspherical spectacle lens described in Patent Document 1 has a rotationally symmetric shape, and the curvature is made equal up to at least 5 mm away from the rotation axis, and the curvature is monotonically increased up to 15 mm away from it (for example, claims 1, 5, etc. of Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the single-focus aspherical spectacle lens described in Patent Document 1, the portion corresponding to the prescription power (for example, the portion through which the line of sight passes when looking at infinity in a front view) is near the rotation axis. Also, the portion through which the line of sight passes when looking at an object at a short distance in the hand is a portion below the rotation axis and below the spectacle lens.

[0006] Patent Document 1 describes how a single-focus aspherical spectacle lens is made aspherical according to the position through which the line of sight passes. Specifically, it employs an aspherical design that maintains a constant curvature near the center of the spectacle lens where the line of sight passes when viewing an object at infinity in a forward-facing view, while increasing the curvature at the lower part of the spectacle lens where the line of sight passes when viewing an object at a close distance, thereby corresponding to the direction of the wearer's gaze.

[0007] On the other hand, the single-vision aspheric spectacle lens described in Patent Document 1 does not reflect distances other than those corresponding to the prescription value, and does not reflect the distance to an object in the direction of the wearer's gaze. In other words, in the peripheral region of the single-vision spectacle lens described in Patent Document 1, the accurate object distance as the gaze passes through that peripheral region is not reflected, and the relationship between the point on the spectacle lens through which the gaze passes and the object distance corresponding to that point is, so to speak, aspheric by default. As a result, there is room for improvement in the certainty of whether the wearer can clearly see the object at that distance.

[0008] However, the lack of addressing object distance in Patent Document 1 is somewhat unavoidable. This is because Patent Document 1 (and the present invention described later) deals with single-focus spectacle lenses for which a prescription value corresponding to only one object distance D0 is set.

[0009] The objective of one embodiment of the present invention is to ensure that, within the framework of a single-focus eyeglass lens, the distance to an object in the direction of the wearer's gaze is taken into account, and that the object at that distance can be clearly and reliably viewed. [Means for solving the problem]

[0010] A first aspect of the present invention is: In a method for designing eyeglass lenses, which are single-focus lenses for which a prescription value corresponding to a single object distance D0 is set, For each position in the planar xy plane of the optical surface of the aforementioned eyeglass lens, an object distance Dn is set from the wearer to a predetermined object when the wearer's line of sight passes through that position, and an object distance setting step is made such that there are three or more types of object distances Dn in the planar xy plane, including the object distance D0. A process for calculating aspherical coefficients, which involves calculating an aspherical coefficient corresponding to each of the object distances Dn at a plurality of predetermined positions, A z-axis coordinate transformation step is performed to convert each of the calculated aspherical coefficients into z-axis coordinates indicating the height for each position, This is a method for designing a single-focus aspherical spectacle lens having [specific characteristics].

[0011] A second aspect of the present invention is: This is a method for designing a single-focus aspherical spectacle lens according to the first embodiment, wherein a range in which the object distance Dn changes and a range in which the object distance Dn does not change are defined in the aforementioned planar xy-plane.

[0012] A third aspect of the present invention is: A method for designing a single-focus aspherical spectacle lens according to the first or second embodiment, wherein, in response to an increase in the distance away from the center of the optical surface, the object distance Dn has at least one mode of change of remaining constant and monotonically increasing, or at least one mode of change of remaining constant and monotonically decreasing.

[0013] A fourth aspect of the present invention is: This is a method for designing a single-focus aspherical spectacle lens according to any one of the first to third embodiments, wherein, in the planar xy-plane, the position where the object distance Dn is set is determined each time the distance increases by 0.1 mm to 2 mm in the direction away from the center of the optical surface.

[0014] A fifth aspect of the present invention is: This is a method for designing a single-focus aspherical spectacle lens according to any one of the first to fourth embodiments, wherein, in the planar xy-plane, 15 to 90 points are set on a single meridian extending from the center of the optical surface, where the object distance Dn is set.

[0015] The sixth aspect of the present invention is In the xy plane in the plan view, on a single meridian extending from the center of the optical surface, in order from the side closer to the center of the optical surface, a range where the object distance Dn is equal (the first one), a range where the object distance Dn monotonically increases or decreases, and a range where the object distance Dn is equal (the second one) are arranged. It is a method for designing a single-focus aspherical spectacle lens according to any one of the first to fifth aspects.

[0016] The seventh aspect of the present invention is In the range where the object distance Dn monotonically increases or decreases in the xy plane in the plan view, 5 to 20 positions where the object distance Dn is set are set. It is a method for designing a single-focus aspherical spectacle lens according to any one of the first to sixth aspects.

[0017] The eighth aspect of the present invention is According to the coordinates of each position of the optical surface of the spectacle lens obtained by the method for designing a single-focus aspherical spectacle lens according to any one of the first to seventh aspects, the optical surface is formed. It is a method for manufacturing a single-focus aspherical spectacle lens.

[0018] The above-mentioned respective steps may be executed by an arithmetic unit in a computer, or the control computer unit including the arithmetic unit may execute the above-mentioned respective steps. That is, an embodiment of the present invention may be applied to a spectacle lens design system or a design apparatus, and may also be applied to a program used in the system. The "steps" described so far may be read as "parts" indicating the configuration in a computer.

Effects of the Invention

[0019] According to the present invention, within the framework of a single-focus spectacle lens, the distance to an object in front of the direction of the wearer's line of sight is taken into account, and a visual recognition target at the object distance can be surely and clearly visually recognized.

Brief Description of the Drawings

[0020] [Figure 1]FIG. 1 is a flowchart showing a method for designing a single-focus aspherical eyeglass lens according to the present invention. [Figure 2A] FIG. 2A is a diagram showing the difference between the degree at the center of the optical surface in the radial direction and the difference between the degree at the center of the optical surface in the circumferential direction across the entire optical surface of the eyeglass lens according to the first embodiment (test example 1-1) of the present invention. [Figure 2B] FIG. 2B is a diagram showing the average degree error and the astigmatism across the entire optical surface of the eyeglass lens according to the first embodiment (test example 1-1) of the present invention. [Figure 2C] FIG. 2C is a diagram showing the relationship between the distance from the center of the minus lens and the object distance Dn according to the first embodiment (test example 1-1) of the present invention. [Figure 3A] FIG. 3A is a diagram showing the difference between the degree at the center of the optical surface in the radial direction and the difference between the degree at the center of the optical surface in the circumferential direction across the entire optical surface of the eyeglass lens according to test example 1-2. [Figure 3B] FIG. 3B is a diagram showing the average degree error and the astigmatism across the entire optical surface of the eyeglass lens according to test example 1-2. [Figure 4A] FIG. 4A is a diagram showing the difference between the degree at the center of the optical surface in the radial direction and the difference between the degree at the center of the optical surface in the circumferential direction across the entire optical surface of the eyeglass lens according to test example 1-3. [Figure 4B] FIG. 4B is a diagram showing the average degree error and the astigmatism across the entire optical surface of the eyeglass lens according to test example 1-3. [Figure 5A] FIG. 5A is a diagram showing the difference between the degree at the center of the optical surface in the radial direction and the difference between the degree at the center of the optical surface in the circumferential direction across the entire optical surface of the eyeglass lens according to the second embodiment (test example 2-1) of the present invention. [Figure 5B] FIG. 5B is a diagram showing the average degree error and the astigmatism across the entire optical surface of the eyeglass lens according to the second embodiment (test example 2-1) of the present invention. [Figure 5C] FIG. 5C is a diagram showing the relationship between the distance from the center of the minus lens and the object distance Dn according to the second embodiment (test example 2-1) of the present invention. [Figure 6A]Figure 6A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 2-2. [Figure 6B] Figure 6B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 2-2. [Figure 7A] Figure 7A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 2-3. [Figure 7B] Figure 7B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 2-3. [Figure 8A] Figure 8A is a diagram showing the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens according to the third embodiment of the present invention (Test Example 3-1). [Figure 8B] Figure 8B shows the average power error and astigmatism across the entire optical surface of an eyeglass lens according to the third embodiment of the present invention (Test Example 3-1). [Figure 8C] Figure 8C shows the relationship between the distance from the center of the negative lens and the object distance Dn according to the third embodiment of the present invention (Test Example 3-1). [Figure 9A] Figure 9A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 3-2. [Figure 9B] Figure 9B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 3-2. [Figure 10A] Figure 10A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 3-3. [Figure 10B] Figure 10B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 3-3. [Figure 11A] Figure 11A is a diagram showing the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens according to the fourth embodiment of the present invention (Test Example 4-1). [Figure 11B] Figure 11B shows the average power error and astigmatism across the entire optical surface of an eyeglass lens according to the fourth embodiment of the present invention (Test Example 4-1). [Figure 11C] Figure 11C shows the relationship between the distance from the center of the negative lens and the object distance Dn according to the fourth embodiment of the present invention (Test Example 4-1). [Figure 12A] Figure 12A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 4-2. [Figure 12B] Figure 12B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 4-2. [Figure 13A] Figure 13A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 4-3. [Figure 13B] Figure 13B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 4-3. [Figure 14A] Figure 14A is a diagram showing the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens according to the fifth embodiment of the present invention (Test Example 5-1). [Figure 14B] Figure 14B shows the average power error and astigmatism across the entire optical surface of the spectacle lens according to the fifth embodiment of the present invention (Test Example 5-1). [Figure 14C] Figure 14C shows the relationship between the distance from the center of the positive lens and the object distance Dn according to the fifth embodiment of the present invention (Test Example 5-1). [Figure 15A]Figure 15A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 5-2. [Figure 15B] Figure 15B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 5-2. [Figure 16A] Figure 16A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 5-3. [Figure 16B] Figure 16B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 5-3. [Figure 17A] Figure 17A is a diagram showing the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens according to the sixth embodiment of the present invention (Test Example 6-1). [Figure 17B] Figure 17B shows the average power error and astigmatism across the entire optical surface of an eyeglass lens according to the sixth embodiment of the present invention (Test Example 6-1). [Figure 17C] Figure 17C shows the relationship between the distance from the center of the positive lens and the object distance Dn according to the sixth embodiment of the present invention (Test Example 6-1). [Figure 18A] Figure 18A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 6-2. [Figure 18B] Figure 18B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 6-2. [Figure 19A] Figure 19A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 6-3. [Figure 19B] Figure 19B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 6-3. [Figure 20A] Figure 20A is a diagram showing the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens according to the seventh embodiment of the present invention (Test Example 7-1). [Figure 20B] Figure 20B shows the average power error and astigmatism across the entire optical surface of an eyeglass lens according to the seventh embodiment of the present invention (Test Example 7-1). [Figure 20C] Figure 20C shows the relationship between the distance from the center of the positive lens and the object distance Dn according to the seventh embodiment of the present invention (Test Example 7-1). [Figure 21A] Figure 21A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 7-2. [Figure 21B] Figure 21B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 7-2. [Figure 22A] Figure 22A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 7-3. [Figure 22B] Figure 22B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 7-3. [Figure 23A] Figure 23A is a diagram showing the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens according to the eighth embodiment of the present invention (test example 8-1). [Figure 23B] Figure 23B shows the average power error and astigmatism across the entire optical surface of an eyeglass lens according to the eighth embodiment of the present invention (test example 8-1). [Figure 23C] Figure 23C shows the relationship between the distance from the center of the positive lens and the object distance Dn according to the eighth embodiment of the present invention (test example 8-1). [Figure 24A]Figure 24A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 8-2. [Figure 24B] Figure 24B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 8-2. [Figure 25A] Figure 25A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction, across the entire optical surface of the spectacle lens related to Test Example 8-3. [Figure 25B] Figure 25B shows the average power error and astigmatism across the entire optical surface of the spectacle lens related to Test Example 8-3. [Modes for carrying out the invention]

[0021] <Definitions and Common Embodiments> The following sections define terms used in this specification and describe aspects common to the following specific embodiments.

[0022] The single-focus aspherical spectacle lenses described herein (hereinafter also simply referred to as "spectacle lenses") have an object-facing surface and an eye-facing surface. The "object-facing surface" is the surface that faces the object when the spectacle lenses are worn by the wearer, and the "eye-facing surface" is the opposite, that is, the surface that faces the eye when the spectacle lenses are worn by the wearer. The object-facing surface may also be called the outer surface, and the eye-facing surface may be called the inner surface.

[0023] In this specification, when viewing the outer surface of an eyeglass lens from a planar perspective (hereinafter referred to as the xy-plane), the left-right direction is defined as the x-direction, the up-down direction as the y-direction, and the direction perpendicular to the x and y directions in the thickness direction of the eyeglass lens as the z-direction. The z-direction is also the optical axis direction of the eyeglass lens. The origin is the center of the optical surface. The center of the optical surface (lens center) refers to at least one of the optical center, geometric center, or centering center (reference point) of the eyeglass lens. In this specification, examples are given for cases where each center coincides.

[0024] The right (3 o'clock direction) is defined as the +x direction, the left (9 o'clock direction) as the -x direction, the upward (12 o'clock direction) as the +y direction, the downward (6 o'clock direction) as the -y direction, the direction towards the object as the +z direction, and the opposite direction (away from the object) as the -z direction. The x direction is also called the x-axis, the y direction as the y-axis, and the z direction as the z-axis. The content of this paragraph can be rephrased as follows: "In the state of wearing eyeglass lenses, the axis passing through the optical center from the object side to the eyeball side is the z-axis, the axis perpendicular to the z-axis from below to above is the y-axis, and the axis perpendicular to the z-axis from left to right is the x-axis."

[0025] In this specification, the location of an eyeglass lens in the xy-plane when viewed from above is referred to as "position." The value of the z-axis, which indicates the height of the surface of the eyeglass lens, is referred to as the "coordinate." The "coordinate of the z-axis indicating the height for each position" is what is commonly known as the sag amount.

[0026] In this specification, "single-vision lens" refers to an eyeglass lens that, unlike bifocal lenses and progressive multifocal lenses, has a prescription value (primarily referring to the S power; other prescription values ​​include C power, astigmatism axis, prism power, etc.) that corresponds to only one object distance D0.

[0027] This wearer information prescription data is printed on the lens bag of the eyeglass lenses. In this specification, the lens bag for single-vision lenses does not include the add power (ADD) for so-called progressive lenses.

[0028] In this specification, a single-focus lens may have, in addition to the measurement reference point for the prescription value corresponding to the single object distance D0, another measurement reference point for confirming the power at a predetermined distance from the center of the optical surface.

[0029] Furthermore, if a lens pouch is included, it is possible to identify it as a monofocal lens based on the wearer's prescription data. Monofocal lenses are typically sold as a set with a lens pouch. Therefore, monofocal lenses that come with a lens pouch also reflect the technical concept of this invention, and the same applies to sets of lens pouches and monofocal lenses.

[0030] There are no limitations to the "single object distance D0"; it can be a so-called long distance (e.g., 2m to infinity), a so-called intermediate distance (e.g., 60cm to 200cm), or a so-called close distance (40cm to 10cm). The single object distance D0 is also called the prescription correspondence distance.

[0031] In one embodiment of the present invention, the region that the line of sight passes through when viewing the prescription distance (infinity in this specification) in a front view, and which includes the center of the optical surface, is referred to as the central region.

[0032] Conversely, when viewing an object at a close distance (hereinafter also simply referred to as "short distance"; this may be numerically equivalent to the above-mentioned near distance, but they are not synonymous), the area through which the line of sight passes, including the area below the spectacle lens, is called the lower region. If a rotationally symmetric aspherical shape is adopted for the spectacle lens, the lower region may also be called the peripheral region.

[0033] The region between the central region and the lower region is called the intermediate region. In the intermediate region, the distance between the prescription range and the distance closest to the user (so to speak, the intermediate distance) becomes the object distance. In the intermediate region, the object distance may be monotonically increased continuously or discretely from the prescription range to the distance closest to the user as the distance from the lens center increases.

[0034] In another embodiment of the present invention, the central region may be set as the area through which the line of sight passes when viewing an object at a close distance, the lower region or peripheral region may be set as the area through which the line of sight passes when viewing an object at the prescription range, and in the intermediate region, the object distance may be monotonically decreased continuously or discretely from the close distance to the prescription range as one moves away from the center of the lens. The embodiment described in this paragraph (also referred to as the "reverse modification") only requires reversing the distance relationship of the embodiment described in the previous paragraph, so a detailed description is omitted.

[0035] One embodiment of the present invention is as follows. In a method for designing eyeglass lenses that are single-focus lenses for which a prescription value corresponding to a single object distance D0 is set, For each position in the planar xy plane of the optical surface of the aforementioned eyeglass lens, an object distance Dn is set from the wearer to a predetermined object when the wearer's line of sight passes through that position, and an object distance setting step is made such that there are three or more types of object distances Dn in the planar xy plane, including the object distance D0. A process for calculating aspherical coefficients, which involves calculating an aspherical coefficient corresponding to each of the object distances Dn at a plurality of predetermined positions, A z-axis coordinate transformation step is performed to convert each of the calculated aspherical coefficients into z-axis coordinates indicating the height for each position, A method for designing a single-focus aspherical spectacle lens having [specific characteristics].

[0036] In the object distance setting process, the object distance Dn is set for each position in the planar xy plane of the optical surface of the eyeglass lens.

[0037] "Object distance Dn" is the distance from the wearer to the object, and can change continuously or discretely depending on the distance away from the center of the optical surface at each point on the planar xy-plane of the optical surface of the spectacle lens.

[0038] In object distance Dn, n is an integer greater than or equal to 2. If n=2, it means that two different object distances D1 and D2 are set (assumed). Furthermore, in one embodiment of the present invention, in the planar xy-plane, there are three or more types of object distance Dn, including object distance D0. That is, when n=2, two positions are set in the planar xy-plane, and at each position (each point), object distances D1 and D2 are set respectively, and D1≠D2 (there are two types of object distance Dn). One of Dn is the prescribed correspondence distance, object distance D0. Object distance Dn is used as a higher-level concept that includes the prescribed correspondence distance D0.

[0039] If n=5, then among the object distances D1 to D5 at each point, D1=D2 and D3=D4=D5 may also be acceptable. In that case, a single-focus spectacle lens is designed that corresponds only to the prescription distance and one other distance (short distance).

[0040] The prescribed distance is the object distance corresponding to the direction the wearer frequently directs their gaze. Strictly speaking, the direction of the gaze differs between object a, which is at infinity, and object b, which is finite but extremely far away. On the other hand, the power required to clearly see both objects remains almost unchanged. Therefore, at the center of the optical plane through which the line of sight passes when viewing object a, which is at infinity, the object distance Dn at each point in the planar xy-plane may be equal.

[0041] The same can be said for the lower region corresponding to short distances as in the paragraph above. The direction of the line of sight differs between an object c at a short distance and an object d a few centimeters closer, yet the power required to clearly see both objects remains almost unchanged. In fact, the lower region near the edge of the spectacle lens is rarely passed through by the line of sight. There is little reason to change the power in this lower region. Therefore, in the lower region through which the line of sight passes when viewing objects c and d at short distances, and which is somewhat away from the edge of the lens, the object distance Dn at each point in the planar xy-plane may be equal.

[0042] As mentioned earlier, in Patent Document 1, the peripheral region (especially the intermediate region) of the spectacle lens is made aspherically without accurately reflecting the object distance. Compared to such Patent Document 1, even if a single-vision spectacle lens is designed that corresponds only to the prescription distance and one other distance (short distance), the effect of the present invention remains unchanged: within the framework of a single-vision spectacle lens, the distance to the object in the direction of the wearer's gaze is taken into account, and the object at that distance can be reliably and clearly seen.

[0043] However, by having more than two types of object distances Dn, it is possible to further accommodate the actual distances to each object that the wearer perceives through the spectacle lens. In particular, at a certain distance between the prescription distance and the short distance (hereinafter simply referred to as the "intermediate distance"; this may be numerically equivalent to the above intermediate distance, but they are not the same), it is preferable to have multiple types of object distances Dn (at least one type (at least three types when considering the entire range from the central region to the lower region, including the prescription distance and the short distance), preferably two or more types, and more preferably 5 to 20 types) at each point in the intermediate region between the central region and the lower region in the planar xy plane of the spectacle lens). In other words, this means that at least three of the above positions (points) are provided in the planar xy plane (preferably on the meridian from the center to the lower end of the spectacle lens).

[0044] As the value of n increases, the positions (points) where the object distance Dn is set will be set at shorter intervals, moving away from the center of the optical surface. If each point is set on the planar xy plane at short intervals from each other, the object distance Dn will change more smoothly in the direction away from the center of the optical surface.

[0045] The following is a specific example of the spacing between each point. In the aforementioned planar xy-plane, the position where the object distance Dn is set may be set for every 0.1 mm to 2 mm increase in the direction away from the center of the optical surface.

[0046] To realize the above specific example, the planar xy plane may be gridded. The spacing of the grid lines may be one value within the range of 0.1 mm to 2 mm in both the x and y directions. By setting the above positions so closely as points, the distance to an object in the direction of the wearer's gaze can be taken more accurately within the framework of a single-focus eyeglass lens, and the object to be seen at that distance can be seen more reliably and clearly.

[0047] In that case, the intersection points of the grid lines in the x-direction and the grid lines in the y-direction become candidates for the above-described positions (each point). Note that the spacing of the grid lines in the x-direction and y-direction may be different. Furthermore, the spacing of each grid line may be different, for example, in the central region, the middle region, and the lower region.

[0048] Of course, instead of gridding the aforementioned planar xy-plane (corresponding to the case where the object distance Dn changes "discretely"), the above points may be set as a continuous plot (for example, Figure 2C shown later) (corresponding to the case where the object distance Dn changes "continuously"). If the expression "each point" is inappropriate (for example, if a concept with area rather than a point is preferred, or if it is inappropriate to describe the plot as being composed of points), the expression "each location" may be used.

[0049] "Distance away from the center of the optical surface" refers to the distance from the center of the optical surface to the position where a new object distance Dn is set, in the xy-plane of the view of the optical surface, in the direction away from the center of the optical surface.

[0050] Another specific example of the spacing between each point (in other words, the number of positions mentioned above) is as follows: In the aforementioned planar xy-plane, 15 to 90 points may be set on a single meridian extending from the center of the optical surface, where the object distance Dn is set. In this specification, "meridian" refers to a line of longitude drawn away from the center of the optical surface of the negative lens, that is, from the center of the optical surface towards the periphery.

[0051] By setting multiple positions as individual points in this way, within the framework of a single-focus eyeglass lens, the distance to an object in the direction of the wearer's gaze can be taken into account more accurately, making it possible to see objects at that distance more reliably and clearly.

[0052] Furthermore, in the aforementioned planar xy-plane, within the range where the object distance Dn is monotonically increasing or decreasing, 5 to 20 points may be set as the positions where the object distance Dn is set. As described above, there is no problem in making the object distance Dn equal in the central region corresponding to the prescription distance and the lower region corresponding to the short distance. It is the intermediate region that should reflect the object distance Dn. By setting a large number of positions as points in this intermediate region, within the framework of a single-focus eyeglass lens, the distance to the object in the direction of the wearer's gaze can be taken in particularly accurately, and the object at that distance can be seen particularly reliably and clearly.

[0053] As described above, in one embodiment of the present invention, a range in which the object distance Dn changes and a range in which the object distance Dn does not change may be set in the planar xy plane. The range in which the object distance Dn changes is the range corresponding to each point in the planar xy plane corresponding to the intermediate region. The range in which the object distance Dn does not change is the range corresponding to each point other than each point in the planar xy plane corresponding to the intermediate region (for example, each point for which one prescription distance is set, and / or each point for which one short distance is set).

[0054] In response to an increase in the distance away from the center of the optical surface, the object distance Dn may be subject to at least one of the following behaviors: remaining constant and monotonically increasing (the former), or remaining constant and monotonically decreasing (the latter, corresponding to the "reverse modification" described above).

[0055] One specific example of the former type described in the paragraph above is as follows: "In the planar xy-plane, along a single meridian extending from the center of the optical surface, the following regions are arranged in order from the side closest to the center of the optical surface: a region where the object distance Dn is equal (1) (corresponding to the central region, i.e., Dn=D0 in the central region), a region where the object distance Dn is monotonically increasing or decreasing (corresponding to the intermediate region), and a region where the object distance Dn is equal (2) (corresponding to the lower region)."

[0056] In the "reverse modification" mentioned earlier, the range where the object distance Dn is equal (part 2) becomes Dn=D0, and the range where the object distance Dn is equal (part 1) corresponds to the short distance.

[0057] In this specific example, the cases where the object distance Dn is constant, monotonically increasing, and then constant in the direction away from the center of the optical surface were illustrated in order, but the present invention is not limited to this. For example, the object distance Dn may be constant and increasing multiple times.

[0058] In the aspherical coefficient calculation step, an aspherical coefficient corresponding to each of the object distances Dn is calculated for each of the set of positions. Then, in the z-axis coordinate transformation step, each of the calculated aspherical coefficients is transformed into a z-axis coordinate representing the height for each position. Both steps will be explained with reference to the drawings.

[0059] Figure 1 shows the steps of the design method for a single-focus aspherical spectacle lens according to the present invention.

[0060] First, the physical properties information of the lens blank to be used, such as the spherical power, refractive index, base curve, and lens thickness, along with positional information of any position on the optical surface of the lens blank, and information on the object distance Dn set for each such position on the optical surface (obtained in the object distance setting step), are input into the computer (S101).

[0061] The computer uses the input information on the physical properties of the lens blank and the object distance Dn for each position on the optical surface to perform an optimization process so that the average power error or astigmatism is minimized for each position on the optical surface (S102). This corresponds to the aspherical coefficient calculation process.

[0062] In the optimization process (S102), the aspheric coefficient for each position on the optical surface is calculated so that the average power error or astigmatism at any position on the optical surface of the single-focus aspheric spectacle lens is minimized.

[0063] In this way, by minimizing the average frequency error or astigmatism at any position on the optical surface, the average frequency error or astigmatism is minimized across the entire optical surface. Minimizing the average frequency error across the entire optical surface is called "optimization of average frequency error." Minimizing astigmatism across the entire optical surface is called "optimization of astigmatism."

[0064] Incidentally, the average frequency error is calculated using (Equation 1) below, and astigmatism is calculated using (Equation 2) below. Average frequency error (APE shown below) = (Difference between the frequency at the center of the optical surface in the radial direction (MP shown below) + Difference between the frequency at the center of the optical surface in the circumferential direction (SP shown below)) / 2 ... (Equation 1) Astigmatism (AS, shown below) = Difference between the frequency at the center of the optical surface in the radial direction (MP, shown below) - Difference between the frequency at the center of the optical surface in the circumferential direction (SP, shown below) ... (Equation 2)

[0065] The computer directly calculates the coordinates corresponding to any position on the optical surface from the aspherical coefficients calculated in the optimization process in S102 (S103). This corresponds to the z-axis coordinate transformation process.

[0066] By using the coordinates of each position on the optical surface of the lens blank to create data for grinding the optical surface of the lens blank with an NC router, or by creating a mold that satisfies the coordinates of each position on the optical surface, it is possible to manufacture single-focus aspherical spectacle glass with the desired optical surface shape.

[0067] According to the embodiment of the present invention described so far, within the framework of a single-focus eyeglass lens, the distance to an object in the direction of the wearer's gaze is taken into account, making it possible to reliably and clearly see the object at that distance.

[0068] Each of the above steps may be executed by the arithmetic unit within the computer, or the control computer unit, including the arithmetic unit, may execute each of the above steps. In other words, one embodiment of the present invention may be applied to an eyeglass lens design system or design apparatus, or to a program used in said system. The "steps" described so far may be read as "units" indicating the configuration within the computer.

[0069] The control computer unit functions as a computer device that performs information processing as instructed by a predetermined program, and is specifically composed of a combination of components such as a CPU (Central Processing Unit), HDD (Hard disk drive), ROM (Read Only Memory), RAM (Random Access Memory), and external interfaces (I / F).

[0070] The following describes several specific embodiments of the present invention. The following is an overview of the specific examples.

[0071] As shown in Test Examples 1-1 and 2-1, "-1" corresponds to one embodiment of the present invention. In other words, it relates to a single-focus spectacle lens in which the object distance Dn is set at each point in the planar xy-plane. This embodiment of the present invention corresponds to the mode in which the object distance Dn changes "continuously" (for example, Figure 2C). At the boundary between the central region and the intermediate region, and at the boundary between the lower region and the intermediate region, the plot is bent, but the plot is continuous. For this reason, this embodiment is classified as a mode in which the object distance Dn changes "continuously".

[0072] As in Test Examples 1-2 and 2-2, "-2" refers to a single-focus spectacle lens where object distances are set at each point in the planar xy-plane, but the set object distance is only the prescription-corresponding distance (i.e., Dn is of only one type).

[0073] As in Test Examples 1-3 and 2-3, "-3" relates to a single-focus spectacle lens in which object distances are set at each point in the planar xy-plane, but the set object distances are only short distances (i.e., only one type of Dn).

[0074] In this specification, Test Example "-1" is an embodiment and corresponds to an example, while Test Examples "-2" and "-3" correspond to comparative examples. Test Examples "-2" and "-3" are collectively referred to as comparative examples. However, in Test Examples "-2" and "-3," unlike the description in Patent Document 1, object distances are set at each point in the planar xy plane despite them being single-focus spectacle lenses. Therefore, although Test Examples "-2" and "-3" correspond to comparative examples, they are not conventional examples.

[0075] In the first to fourth embodiments shown below (Test Examples 1-1, 2-1, 3-1, 4-1), a negative lens with a spherical power of -3.00D (base curve 1.997D, lens center thickness 1.0mm) is used as the lens blank. On the other hand, in the fifth to eighth embodiments (Test Examples 5-1, 6-1, 7-1, 8-1), a positive lens with a spherical power of +3.00D (base curve 4.441D, lens center thickness 4.7mm) is used as the lens blank. In the first, second, fifth, and sixth embodiments shown below, the object distance in the central region is set to infinity, and the object distance in the lower region is set to a short distance. On the other hand, in the third, fourth, seventh, and eighth embodiments, the object distance in the central region is set to a short distance, and the object distance in the lower region is set to infinity (corresponding to the "reverse modification" described above). In the first, third, fifth, and seventh embodiments shown below, the target of optimization is astigmatism. Therefore, in Figures 2B, 8B, 14B, and 20B, astigmatism (AS) is near zero across the meridian. On the other hand, in the second, fourth, sixth, and eighth embodiments, the target of optimization is the average frequency error. Therefore, in Figures 5B, 11B, 17B, and 23B, the average frequency error (APE) is near zero across the meridian.

[0076] <First Embodiment of the Present Invention (Test Example 1-1)> A first embodiment of the present invention (Test Example 1-1) will be described with reference to Figures 2 to 4. Figure 2 shows the first embodiment of the present invention. Figure 3 shows Test Example 1-2. Figure 4 shows Test Example 1-3.

[0077] In the first embodiment, a negative lens with a spherical power of -3.00D, refractive index of 1.596D, base curve of 1.997D, and center thickness of 1.0mm is used as the lens blank. The optical surface of this negative lens is a surface with rotational symmetry.

[0078] Figure 2A shows the difference between the power at the center of the optical surface in the radial direction (horizontal axis value, MP, hereafter the same) and the difference between the power at the center of the optical surface in the circumferential direction (horizontal axis value, SP, hereafter the same) across the entire optical surface of the negative lens. Both horizontal axis values ​​are expressed as Difference from center power (unit: D) ​​in the figure. This is also the case in Figures 3A to 25A.

[0079] Figure 2B shows the astigmatism (horizontal axis value, AS, hereafter the same) minimized across the entire optical surface using these object distances Dn, which are set individually at 0.1 mm intervals from the center of the optical surface (vertical axis value) along the meridian drawn from the center of the optical surface toward the periphery, and the average frequency error (horizontal axis value, APE, hereafter the same) corresponding to this astigmatism. The same applies to Figures 3B to 25B.

[0080] Figure 2C shows an example in which the object distance Dn increases or decreases within a certain range on the optical surface depending on the wearer's usage.

[0081] As shown in Figure 2C, along the meridian drawn away from the center of the optical surface of this negative lens, that is, along the line of longitude drawn from the center of the optical surface toward the periphery, the center of the optical surface of the negative lens is set to 0 mm, and the object distance Dn in the range of 0 to 5 mm is set to 0D (e.g., the distance of only one object D0 is the prescribed distance), i.e., infinity.

[0082] Similarly, the object distance Dn in the range of 20-40 mm from the center of the optical plane is set to a fixed value of 3.33D, or 30 cm (e.g., short distance).

[0083] Furthermore, the object distance Dn (e.g., medium distance) in the range of 5 to 20 mm from the center of the optical surface is set to change linearly within the range of 5 to 20 mm from the center, with 0D at 5 mm from the center and 3.33D at 20 mm from the center.

[0084] In other words, in the first embodiment, the range from 0 to 5 mm from the center of the optical surface is set as the central region, the range from 20 to 40 mm from the center is set as the lower region, and the range from 5 to 20 mm from the center, i.e., the range existing between the central region and the lower region, is set as the intermediate region.

[0085] In Figure 2C, the object distance Dn changes linearly with respect to the distance away from the center of the optical surface (distance) in the range of 5 to 20 mm from the center of the optical surface, i.e., the intermediate region.

[0086] Figure 2C shows the case where, in the intermediate region, the object distance Dn is set at equal intervals of 0.1 mm, i.e., every 0.1 mm increase in the distance away from the center of the optical surface. When setting a new object distance Dn, the position on the optical surface and the object distance Dn at that position are plotted on a graph, and the graph in Figure 2C is obtained by connecting each plotted point with a straight line.

[0087] In the first embodiment, astigmatism is minimized across the entire optical surface of the negative lens. Specifically, information on the physical properties of the negative lens and information on the object distance Dn, which is set according to the distance from the center of the optical surface of the negative lens as shown in Figure 2C, are input to the computer. Using the input information, the computer calculates the aspheric coefficient for each position on the optical surface of the negative lens so that astigmatism is minimized at any position on the optical surface, and calculates coordinates from the calculated aspheric coefficients. The optical surface formed using the coordinates for each position of the optical surface calculated in this way is a rotationally symmetric plane.

[0088] In the test examples 1-2 shown in Figures 3A and 3B, the same type of negative lens used in the first embodiment of the present invention is used, but the object distance Dn, or prescription correspondence distance 0D, in the range of 0 to 5 mm from the center of the optical surface of the negative lens is applied to the range of 0 to 40 mm from the center of the optical surface, i.e., the entire optical surface, to minimize astigmatism.

[0089] Figure 3A shows the difference between the power at the center of the optical surface in the radial direction and the power at the center of the optical surface in the circumferential direction across the entire optical surface of the negative lens. Figure 3B shows the average power distribution and astigmatism when the prescription correspondence distance 0D is applied not only to the central region but also to the lower and intermediate regions.

[0090] Test Examples 1-3, shown in Figures 4A and 4B, relate to the case in the embodiment shown in Figures 3A and 3B where the short distance 3.33D is applied not only to the lower region but also to the central and intermediate regions, instead of the prescription correspondence distance 0D.

[0091] In other words, Test Examples 1-2 shown in Figures 3A and 3B, and Test Examples 1-3 shown in Figures 4A and 4B, correspond to curvature distributions optimized for prescription distances and curvature distributions optimized for short distances. In Figures 3B and 4B, astigmatism in the intermediate region, i.e., the range of 5 to 20 mm from the center of the optical surface, is not near zero. On the other hand, as shown in Figure 2B, in the first embodiment of the present invention, astigmatism is substantially near zero throughout the entire intermediate region.

[0092] Thus, according to the first embodiment of the present invention, astigmatism in the entire intermediate region of the optical surface, which was difficult to achieve in Comparative Example 1, can be reduced to substantially near zero.

[0093] <Second Embodiment of the Present Invention (Test Example 2-1)> A second embodiment of the present invention will be described with reference to Figures 5 to 7. Figure 5 shows the second embodiment of the present invention (Test Example 2-1). Figure 6 shows Test Example 2-2. Figure 7 shows Test Example 2-3. Test Examples 2-2 and 2-3 together will be referred to as Comparative Example 2.

[0094] Furthermore, in Figures 6B and 7B, the average frequency error in the intermediate region, i.e., the range of 5 to 20 mm from the center of the optical surface, is not near zero. On the other hand, as shown in Figure 5B, in the second embodiment of the present invention, the average frequency error is substantially near zero throughout the entire intermediate region. Thus, according to the second embodiment of the present invention, the average frequency error throughout the entire intermediate region of the optical surface, which was difficult to achieve in Comparative Example 2, can be substantially near zero. The same can be said for each of the subsequent embodiments and their corresponding comparative examples. Therefore, each of the subsequent embodiments will be described only minimally.

[0095] <Third Embodiment of the Present Invention (Test Example 3-1)> A third embodiment of the present invention will be described with reference to Figures 8 to 10. Figure 8 shows the third embodiment of the present invention (Test Example 3-1). Figure 9 shows Test Example 3-2. Figure 10 shows Test Example 3-3. Test Examples 3-2 and 3-3 together will be referred to as Comparative Example 3.

[0096] <Fourth Embodiment of the Present Invention (Test Example 4-1)> A fourth embodiment of the present invention will be described with reference to Figures 11 to 13. Figure 11 shows the fourth embodiment of the present invention (Test Example 4-1). Figure 12 shows Test Example 4-2. Figure 13 shows Test Example 4-3. Test Examples 4-2 and 4-3 together will be referred to as Comparative Example 4.

[0097] <Fifth Embodiment of the Present Invention (Test Example 5-1)> A fifth embodiment of the present invention will be described with reference to Figures 14 to 16. Figure 14 shows the fifth embodiment of the present invention (Test Example 5-1). Figure 15 shows Test Example 5-2. Figure 16 shows Test Example 5-3. Test Examples 5-2 and 5-3 together will be referred to as Comparative Example 5.

[0098] <Sixth Embodiment of the Present Invention (Test Example 6-1)> A sixth embodiment of the present invention will be described with reference to Figures 17 to 19. Figure 17 shows the sixth embodiment of the present invention (Test Example 6-1). Figure 18 shows Test Example 6-2. Figure 19 shows Test Example 6-3. Test Examples 6-2 and 6-3 together will be referred to as Comparative Example 6.

[0099] <Seventh Embodiment of the Present Invention (Test Example 7-1)> A seventh embodiment of the present invention will be described with reference to Figures 20 to 22. Figure 20 shows the seventh embodiment of the present invention (Test Example 7-1). Figure 21 shows Test Example 7-2. Figure 22 shows Test Example 7-3. Test Examples 7-2 and 7-3 together will be referred to as Comparative Example 7.

[0100] <Eighth Embodiment of the Present Invention (Test Example 8-1)> An eighth embodiment of the present invention will be described with reference to Figures 23 to 25. Figure 23 shows the eighth embodiment of the present invention (Test Example 8-1). Figure 24 shows Test Example 8-2. Figure 25 shows Test Example 8-3. Test Examples 8-2 and 8-3 together will be referred to as Comparative Example 8.

[0101] The ranges of the central region, intermediate region, and lower region set on the optical surface of the lens blank according to the present invention are not limited to the specific ranges shown in the first to eighth embodiments of the present invention, but can be appropriately modified according to the prescription of each optician. Furthermore, in the present invention, it is not necessary to clearly define the boundaries between the central region, intermediate region, and lower region on the optical surface.

[0102] Furthermore, in the first to eighth embodiments of the present invention, the following regions are set on the optical surface in the direction away from the center of the optical surface: a central region or lower region where the object distance Dn is a fixed value, an intermediate region where the object distance Dn changes linearly, and then a lower region or central region where the object distance Dn is a fixed value. However, in the present invention, the object distance Dn may change continuously or discretely within a part of the range of the central region or lower region.

[0103] Furthermore, in the first to eighth embodiments of the present invention, as shown in Figure 2C, the object distance Dn increased or decreased linearly with respect to the distance from the center of the optical surface in the intermediate region. However, in the present invention, the object distance Dn may increase or decrease curvilinearly with respect to the distance from the center of the optical surface, following an arc.

[0104] According to one embodiment of the present invention, the following effects are also achieved.

[0105] In a single-focus aspherical spectacle lens, the curvature of the optical surface changes over a wide area of ​​the optical surface, moving away from the center, i.e., from the center to the periphery. This allows for a continuous refractive force to exist on the optical surface. As a result, the single-focus aspherical spectacle lens according to one specific example of the present invention exhibits excellent visibility.

[0106] Furthermore, because the object distance Dn is varied over a wide area of ​​the optical surface, the design flexibility of the optical surface shape is increased.

[0107] Furthermore, since the aspherical coefficient is calculated directly from the object distance Dn over the range on the optical surface where the object distance Dn changes, it is possible to calculate an aspherical coefficient that accurately fits the object distance Dn. As a result, the average frequency error or astigmatism can be reduced over the range on the optical surface where the object distance Dn changes.

Claims

1. In a method for designing eyeglass lenses, which are single-focus lenses for which a prescription value corresponding to a single object distance D0 is set, For each position in the planar xy plane of the optical surface of the aforementioned eyeglass lens, an object distance Dn is set from the wearer to the object when the wearer's line of sight passes through that position when viewing a predetermined object, and an object distance setting step is made such that there are three or more types of object distances Dn in the planar xy plane, including the object distance D0. A process for calculating aspherical coefficients, which involves calculating an aspherical coefficient corresponding to each of the object distances Dn at a plurality of predetermined positions, A z-axis coordinate transformation step is performed to convert each of the calculated aspherical coefficients into z-axis coordinates indicating the height for each position, A method for designing a single-focus aspherical spectacle lens having [a specific characteristic].

2. A method for designing a single-focus aspherical spectacle lens according to claim 1, wherein a range in which the object distance Dn changes and a range in which the object distance Dn does not change are set in the planar xy plane.

3. A method for designing a single-focus aspherical spectacle lens according to claim 1, wherein, in response to an increase in the distance away from the center of the optical surface, the object distance Dn has at least one mode of change of remaining constant and monotonically increasing, or at least one mode of change of remaining constant and monotonically decreasing.

4. A method for designing a single-focus aspherical spectacle lens according to claim 1, wherein in the planar xy plane, the position where the object distance Dn is set is set each time the distance increases by 0.1 mm to 2 mm in the direction away from the center of the optical surface.

5. A method for designing a single-focus aspherical spectacle lens according to claim 4, wherein, in the planar xy plane, 15 to 90 points are set on a single meridian extending from the center of the optical surface, where the object distance Dn is set.

6. A method for designing a single-focus aspherical spectacle lens according to claim 4, wherein, in the planar xy-plane, on a single meridian extending from the center of the optical surface, the following ranges are arranged in order from the side closest to the center of the optical surface: a range where the object distance Dn is equal (the first), a range where the object distance Dn is monotonically increasing or decreasing, and a range where the object distance Dn is equal (the second).

7. A method for designing a single-focus aspherical spectacle lens according to claim 6, wherein, in the planar xy plane, five to twenty positions are set where the object distance Dn is monotonically increasing or monotonically decreasing.

8. A method for manufacturing a single-focus aspherical spectacle lens, comprising shaping the optical surface of a spectacle lens obtained by the design method for a single-focus aspherical spectacle lens according to the coordinates of each position of the optical surface of the spectacle lens according to any one of claims 1 to 7.

Images