JPH1078567A - Manufacture of progressive multifocus lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a manufacture equipment cost and a management cost, to reduce the burdens of a worker and to prevent work errors by setting surface refractive power at a far-sight part measurement reference point smaller for a progressive refractive surface for manufacturing the progressive multifocus lens of larger joining refractive power. SOLUTION: A manufacture range is divided into plural blocks by the value of far-sight part vertex refractive power. Inside the respective blocks, one of the front surface and rear surface of a lens is turned to a common progressive refractive surface corresponding to the joining refractive power, the shape of the other surface is changed and prescribed far-sight part vertex refractive power is obtained. That is, for each joining refractive power ADD, in the relation of the far-sight part surface refractive power D1F of the progressive refractive surface and rear surface refractive power D2 capable of obtaining the far-sight vertex refractive power SPH+4.000ptr, CYL+0.000ptr, the surface refractive power at the far-sight part side measurement reference point is set smaller for the progressive refractive surface for manufacturing the progressive multifocus lens of the larger joining refractive power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a progressive multifocal lens.

[0002]

2. Description of the Related Art The range of production of a conventional spectacle lens is shown in, for example, a combination table of a spherical refractive power SPH and a cylindrical refractive power CYL as shown in FIGS. 8 (a), 8 (b) and 8 (c). Have been. In the case of the progressive multifocal lens, since there is a combination with the addition refractive power ADD, a three-dimensional table is obtained.

In order to process such progressive multifocal lenses having various refractive powers, a conventional spectacle lens manufacturer uses a distance portion vertex power (spherical power and cylindrical power) as shown in FIG. b) alphabets A, B, C, D, E
As shown by, the production range is divided into a plurality of blocks, and in each block, one of the front surface and the rear surface of the lens is a common progressive refraction surface corresponding to the addition power ADD. Then, in order to obtain a desired far-distance vertex refractive power, the shape of the surface on the side opposite to the progressive refractive surface is changed. For example, the addition power ADD2.00 diopters (Dpt
In (r), in order to obtain a total of 36 types of far vision apex powers in the range indicated by D in FIG. 8 (b), one common progressive refractive surface is used on the front surface of the lens, and the rear surface of the lens is , 4 types of spherical surfaces and 32 types of toric surfaces.

More specifically, the spherical power SPH + 4.
In order to produce a progressive multifocal lens having a refractive power of 00 Dptr, a cylindrical refractive power of CYL + 0.00 Dptr, and an additional refractive power of ADD of 2.00 Dptr, the front surface must have a surface refractive power of a distance reference portion reference point (distance refractive power of 7.00 Dptr). A progressive refraction surface having an addition power of ADD 2.00 Dptr is used, and a rear surface is a spherical surface of -3.24 Dptr. In addition, spherical refractive power SPH + 3.50 Dptr, cylindrical refractive power CY
In order to manufacture a progressive multifocal lens with L + 0.50 Dptr and addition power ADD2.00 Dptr, the front surface is a progressive refraction surface similar to the above, and the rear surface is a toric surface of -3.74 / -3.24 Dptr.

In the conventional method of manufacturing a progressive multifocal lens, the progressive surface of the same common block has an addition power AD.
Irrespective of D, the refractive power of the distance portion was almost constant. For example, the addition refractive power ADD4.D in the D block in FIG.
The distance refractive power of the progressive power surface for 00 Dptr was 7.00 Dptr, the same as that for ADD 2.00 Dptr. In this case, the spherical refractive power SPH + 4.00 Dptr,
Cylindrical refractive power CYL + 0.00 Dptr, addition refractive power ADD
When manufacturing a progressive multifocal lens of 4.00 Dptr,
The front surface has a distance power of 7.00 Dptr and an added power of 4.0.
A progressive refraction surface for 0 Dptr. Here, the rear surface is
Assuming a spherical surface of 3.24 Dptr, the distance power at the vertex is SP
H + 4.06 Dptr. When the addition refractive power ADD is 2.00 Dptr, the center thickness is 6.90 mm. However, when the addition refractive power ADD becomes 4.00 Dptr, the curvature of the progressive refractive surface increases, and the center thickness becomes 7.85 mm. In this case, the refractive power of the distance portion becomes high due to the influence of the change in the lens thickness.

FIGS. 9 (a) and 9 (b) show vertical sectional views of spectacle lenses when the addition power ADD is 2.00 Dptr and 4.00 Dptr. 9A and 9B, reference numerals 15 and 16 denote the front surface of the lens, 25 and 26 denote the rear surface of the lens, 35 and 36 denote progressive refraction surfaces, 45 and 46 denote distance reference measurement reference points, and 55 and 46, respectively. Reference numeral 56 denotes a reference point for measuring the addition power of the near portion. In the case of a conventional lens having an addition refractive power ADD of 4.00 Dptr, if the rear surface is a spherical surface of −3.30 Dptr, a spherical refractive power SPH + 4.00 Dptr is obtained. In Conventional Example 1, for each addition refractive power ADD, the distance portion surface refractive power D1F of the progressive refractive surface and the distance portion vertex power SPH + 4.
When the back surface refractive power D2 for obtaining 00 Dptr and CYL + 0.00 Dptr is obtained, the result is as shown in Table 1 and FIG. In FIG. 10, the horizontal axis represents the addition refractive power ADD, and the vertical axis represents the distance portion surface refractive power D1F on the upper side and the rear surface refractive power D2 on the lower side.

Conventional example 1

[Table 1]

In FIG. 8, an A block is added with an additional refractive power A.
In the case of manufacturing with a progressive refractive surface having a constant distance refractive power of 5.00 Dptr irrespective of DD, a spherical refractive power SPH + 1.
The back surface refractive power for producing a progressive multifocal lens having a refractive power of 00 Dptr, a cylindrical refractive power CYL + 0.00 Dptr, and an add power ADD 2.00 Dptr is -4.07 Dptr. Then, the spherical refractive power becomes SPH + 0.99 Dptr. When applied to the addition refractive power ADD4.00 Dptr, the spherical refractive power SPH is obtained.
+1.04 Dptr.

With respect to the conventional example 2, each addition refractive power ADD
In each case, the distance portion surface power D1F of the progressive refraction surface and the distance portion vertex power SPH + 1.00Dptr, CYL + 0.00Dp
When the rear refractive power D2 for obtaining tr is obtained, the result is as shown in Table 2 and FIG. In FIG. 11, the horizontal axis represents the addition refractive power ADD, the vertical axis represents the distance portion surface refractive power D1F on the upper side, and the rear surface refractive power D2 on the lower side.

Conventional example 2

[Table 2]

As described above, in the conventional lens technology, the refractive power of the distance portion of the progressive refraction surface is set to be constant regardless of the addition power ADD. It was necessary to adjust the surface refractive power of the surface on the opposite side of the progressive refraction surface according to the addition refractive power ADD. Therefore, when a finished product of a progressive multifocal lens is manufactured by molding, various types of spherical molds and toric molds for molding the surface opposite to the progressive refraction surface are required. Further, when a semi-finished product having a progressive refraction surface formed in advance is ground and polished to produce a finished progressive multifocal lens, various types of polishing plates are required. If there are many types of molds and polishing plates, there is a problem that manufacturing equipment costs and management costs increase, and a burden on a processor also increases, which easily leads to a processing error.

[0012]

SUMMARY OF THE INVENTION The present invention reduces the number of molds for forming the surface opposite to the progressive refraction surface and the types of polishing plates for polishing, thereby reducing manufacturing equipment costs and management costs, and It is an object of the present invention to provide a method of manufacturing a progressive multifocal lens capable of reducing a load and preventing a processing error.

[0013]

SUMMARY OF THE INVENTION To achieve this object, a method of manufacturing a progressive multifocal lens according to the present invention is provided in a progressive multifocal lens product group that includes a manufacturing range of a predetermined distance portion vertex power and a predetermined addition power. A method for manufacturing a multifocal lens,
The manufacturing range is divided into a plurality of blocks according to the value of the distance portion vertex refractive power, and in each block, one of the front surface and the rear surface of the lens is a common progressive refractive surface according to the addition power. By changing the shape of the other surface to obtain a predetermined distance refractive power at the vertex, the progressive refraction surface for manufacturing a progressive addition lens having a larger addition power has a higher surface refractive power at the distance measuring reference point. The feature is that the force is set small.

In particular, according to the present invention, the surface refractive power of the section along the principal meridian at the distance reference point is DFm, and the surface refractive power of the section orthogonal to the principal meridian at the distance reference point. In the method of manufacturing a progressive multifocal lens that satisfies DFm <DFs, DFs <DFs, in a block having the same apex refractive power at the far vision portion, the progressive power surface having a larger addition power has a greater distance measurement reference point. The average surface refractive power at is reduced. Note that the average surface power is the surface power DF.
The arithmetic mean of m and DFs. Further, in the present invention, when a change in surface refractive power of a cross section along the principal meridian at a distance measurement reference point due to a change in addition refractive power is ΔDFm, and a change in surface refractive power of a cross section orthogonal to the main meridian is ΔDFs, , | ΔDFm | <| ΔDFs |.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIGS. 1 and 2 are graphs showing the surface refractive power of Examples 1 and 2 of progressive multifocal lenses to which the present invention is applied, the front surface of which is a progressive refraction surface and the rear surface of which is a spherical surface. 1 and 2, the horizontal axis represents the addition refractive power ADD, and the vertical axis represents the distance portion surface power D1F on the upper side and the rear surface power D2 on the lower side.

Table 3 shows the results obtained in the first embodiment shown in FIG.
For each addition refractive power ADD, the distance portion surface refractive power D1F of the progressive refraction surface and the distance portion vertex power SPH + 4.00 Dptr, C
Back surface power D2 that can obtain YL + 0.00 Dptr
It is a specific numerical example of the relationship with.

Embodiment 1

[Table 3]

Table 4 shows the results obtained in the second embodiment shown in FIG.
For each addition refractive power ADD, the distance portion surface power D1F of the progressive refraction surface and the distance portion vertex power SPH + 1.00 Dptr, C
Back surface power D2 that can obtain YL + 0.00 Dptr
It is a specific numerical example of the relationship with.

Embodiment 2

[Table 4]

According to the first and second embodiments, in a lens group having the same distance portion vertex power, the rear surface of the lens can be formed into a common spherical surface regardless of the addition power ADD. Was.

FIG. 3 is a vertical sectional view of a spectacle lens having a rear surface as a progressive refractive surface. In the third embodiment in which the present invention is applied to this spectacle lens, for each addition refractive power ADD, the distance portion surface power D2F of the progressive refraction surface and the distance portion vertex power S
Table 5 and FIG. 4 show the relationship between the front refractive power D1 at which PH + 4.00 Dptr and CYL + 0.00 Dptr can be obtained. In FIG. 3, reference numeral 11 denotes a front surface of the lens, 21 denotes a rear surface of the lens, 31 denotes a progressive refraction surface, 41 denotes a distance reference point, and 51 denotes a near addition power reference point.

Embodiment 3

[Table 5]

According to the third embodiment, the front surface 11 can be a common spherical surface irrespective of the addition power ADD of the progressive refractive surface 31 of the rear surface 21.

FIG. 5 shows that the front surface is a progressive refractive surface, and a predetermined difference is made between the surface refractive power of the meridional section along the principal meridian at the distance measuring reference point and the surface refractive power of the sagittal section perpendicular to the principal meridian. FIG. 4 is a front view of a lens that is made thinner and lighter by lowering a base curve (refractive power of the front surface of the lens).

Example 6 in which the present invention was applied to the lens shown in FIG. 5 is shown in Table 6 and FIG. Table 6 and FIG. 6 show, for each addition refractive power ADD, the sectional refractive power D1Fm along the principal meridian at the distance measuring reference point of the progressive refractive surface, the sectional refractive power D1Fs orthogonal to the principal meridian, and the distance use. It shows the relationship with the rear surface refractive power D2 that can obtain a vertex power SPH + 4.00 and CYL + 0.00Dptr. In addition,
5, reference numeral 32 denotes a progressive refractive surface, reference numeral 42 denotes a distance reference point, reference numeral 52 denotes a near addition power measurement reference point, reference numeral 62 denotes a principal meridian, reference numeral 72 denotes a meridional section, and reference numeral 82 denotes a sagittal section. . In FIG. 6, the sign m is the addition power A.
DD and sectional refractive power D1F at meridional section 72
The symbol s indicates the relationship between the added refractive power ADD and the sectional refractive power D1Fs in the sagittal section 82.

Embodiment 4

[Table 6]

Example 7 in which the present invention was applied to the lens shown in FIG. 5 is shown in Table 7 and FIG. Table 7 and FIG. 7 show, for each addition refractive power ADD, the sectional refractive power D1Fm along the principal meridian at the distance measuring reference point of the progressive refractive surface, the sectional refractive power D1Fs orthogonal to the principal meridian, and the distance use. It shows the relationship with the rear surface refractive power D2 for obtaining the apex refractive power SPH + 2.00 Dptr and CYL + 0.00 Dptr.

Embodiment 5

[Table 7]

In Examples 4 and 5, when the surface refractive power of a section along the principal meridian at the distance reference point is D1Fm and the surface refractive power of a section orthogonal to the principal meridian is D1Fs, D1Fm <D1Fs is satisfied. To be satisfied. Further, as can be seen from FIGS. 6 and 7, in Examples 4 and 5, the change in the surface power of the cross section along the main meridian at the distance measurement reference point due to the change in the addition power ADD is ΔD1Fm, the main meridian and Assuming that the change in the surface refractive power of the orthogonal cross section is ΔD1Fs, | ΔD1Fm | <| ΔD1Fs | is satisfied.

As described above, according to the progressive multifocal lens configurations of the fourth and fifth embodiments, the rear surface can be a common spherical surface irrespective of the addition refractive power ADD of the front progressive surface.

[0031]

As is clear from the above description, according to the present invention, the surface on the opposite side of the progressive refraction surface for obtaining the same refractive power at the apex of the far vision can be commonly used regardless of the addition power. Thus, when a finished product of the progressive multifocal lens is manufactured, the types of the spherical type and the toric type for molding the surface opposite to the progressive refraction surface can be reduced. In the lens manufactured according to the present invention, the lens thickness increases as the addition refractive power increases, and the refractive power of the distance portion vertex becomes stronger under the influence of the change in the lens thickness. Since the correction is made by reducing the surface refractive power, the surface on the opposite side to the progressive refraction surface does not need to be corrected. Further, according to the present invention, when a semi-finished product in which a progressive refracting surface is formed in advance is ground and polished to produce a finished progressive multifocal lens, the burden on the processor is reduced, and processing errors are reduced.

[Brief description of the drawings]

FIG. 1 is a graph showing the surface refractive power of a lens of Example 1 manufactured by a manufacturing method of the present invention.

FIG. 2 is a graph showing a surface refractive power of a lens of Example 2 manufactured by a manufacturing method of the present invention.

FIG. 3 is a vertical sectional view of another lens to which the manufacturing method of the present invention is applied.

FIG. 4 is a graph showing the surface refractive power of the lens of Example 3 in which the manufacturing method of the present invention is applied to the lens shown in FIG. 3;

FIG. 5 is a front view of still another lens to which the manufacturing method of the present invention is applied.

FIG. 6 is a graph showing the surface refractive power of the lens of Example 4 in which the manufacturing method of the present invention is applied to the lens shown in FIG.

FIG. 7 is a graph showing the surface refractive power of the lens of Example 5 in which the manufacturing method of the present invention is applied to the lens shown in FIG. 5;

FIGS. 8A, 8B, and 8C are tables showing examples of a manufacturing range and blocking of a progressive multifocal lens.

FIGS. 9A and 9B are diagrams showing the relationship between the addition power and the lens thickness when the front surface of the lens is a progressive surface.

FIG. 10 is a graph showing the surface refractive power of a conventional lens in a graph.

FIG. 11 is a graph showing the surface refractive power of another conventional lens.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Front surface of lens 21 Rear surface of lens 31 Progressive refraction surface 32 Progressive refraction surface 41 Distance measurement reference point 42 Distance measurement reference point 51 Near addition power measurement reference point 52 Near addition power measurement reference point 62 Main meridian 72 Meridional section 82 Sagittal section

Claims (4)

[Claims] 1. A method of manufacturing a progressive multifocal lens in a progressive multifocal lens product group including a production range of a predetermined distance portion vertex power and a predetermined addition power, wherein the production range is a distance portion. Divided into a plurality of blocks according to the value of the vertex refractive power, and within each block, one of the front surface and the rear surface of the lens is a common progressive refractive surface according to the added refractive power, and the shape of the other surface is A predetermined distance portion vertex refractive power is obtained, and the surface refractive power at the distance portion measurement reference point is set to be smaller for a progressive power surface for producing a progressive addition lens having a larger addition power. A method of manufacturing a progressive multifocal lens. 2. A progressive multifocal lens according to claim 1, wherein, when said predetermined distance portion vertex power is the same, the other surface has the same surface power regardless of said additional power. Method. 3. It has a positive far-distance portion vertex power, and the surface refractive power of a section along the principal meridian at the far-distance portion measurement reference point is D
Fm, where DFs is a surface refractive power of a cross section orthogonal to the principal meridian, a method of manufacturing a progressive multifocal lens in which DFm <DFs is satisfied. The method of manufacturing a progressive multifocal lens, characterized in that the average surface refractive power at the distance measuring reference point is set to be smaller as the progressive refraction surface becomes. 4. The method according to claim 3, wherein the change in the surface refractive power of the cross section along the principal meridian at the distance measuring reference point due to the change in the addition refractive power is ΔDFm, and the change in the surface refractive power of the cross section orthogonal to the main meridian. Where ΔDFs is satisfied, | ΔDFm | <| ΔDFs | is satisfied.