Method and apparatus for manufacturing spectacle lens

Abstract

Provided are a method and an apparatus for manufacturing a spectacle lens, with which it is possible to automatically determine the state of an outer edge of a lens surface. This method for manufacturing a spectacle lens comprises: an imaging step for capturing an image of a lens base material L; and an outer edge state determination step for extracting outer edge distance information including information of the distance R from the center of a virtual circumscribed circle Vc circumscribing a lens surface outer edge L1a of a lens surface L1 of the lens base material L to the lens surface outer edge L1a at a plurality of positions on the lens surface outer edge L1a on the basis of the image obtained in the imaging step, and determining the shape of the lens surface outer edge L1a on the basis of the outer edge distance information.

Description

Eyeglass lens manufacturing method and manufacturing device

[0001] The present invention relates to a method and an apparatus for manufacturing eyeglass lenses.

[0002] BACKGROUND ART Conventionally, there are known methods for manufacturing eyeglass lenses by subjecting lens substrates to various processes (see, for example, Patent Document 1).

[0003] JP 2014-85610 A

[0004] In the manufacturing process of such eyeglass lenses, it is sometimes necessary to check the condition of the outer edge of the lens surface in order to confirm the condition of the lens substrate. Conventionally, this checking of the condition of the outer edge of the lens surface has been done visually by an operator, which requires a lot of manpower for the checking work and is a factor that hinders automation of the manufacturing process. Furthermore, since the checking work involves judging the condition based on subjective intuition, there has been a problem in that the judgment results are prone to variation.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method and apparatus for manufacturing eyeglass lenses that are simple in configuration and capable of automatically determining the state of the outer edge of the lens surface.

[0006] One aspect of the method for manufacturing an eyeglass lens of the present invention solves the above problem by comprising: an imaging step of imaging a lens substrate; and an outer edge state determination step of extracting, based on the images obtained in the imaging step, outer edge distance information including the distance from the center of an imaginary circumscribing circle circumscribing the outer edge of the lens surface at multiple locations on the outer edge of the lens surface of the lens substrate to the lens surface outer edge, and determining the shape of the lens surface outer edge based on the outer edge distance information. Another aspect of the method for manufacturing an eyeglass lens of the present invention solves the above problem by comprising: an imaging step of imaging a lens substrate; and an outer edge state determination step of extracting the lens surface outer edge of the lens surface of the lens substrate based on the images obtained in the imaging step, and determining whether or not the outer edge of the lens substrate needs to be chamfered based on the lens surface outer edge. One aspect of the eyeglass lens manufacturing apparatus of the present invention solves the above problem by comprising an imaging device that images a lens substrate, and an outer edge state determination unit that extracts outer edge distance information including distances from the center of an imaginary circumscribing circle circumscribing the outer edge of the lens surface at multiple locations on the outer edge of the lens substrate based on images obtained by the imaging device to the outer edge of the lens surface, and determines the shape of the outer edge of the lens surface based on the outer edge distance information. Another aspect of the eyeglass lens manufacturing apparatus of the present invention solves the above problem by comprising an imaging device that images a lens substrate, and an outer edge state determination unit that extracts the outer edge of the lens surface of the lens substrate based on images captured by the imaging device, and determines whether or not the outer edge of the lens substrate needs to be chamfered based on the outer edge of the lens surface.

[0007] According to the present invention, the state of the outer edge of the lens surface can be automatically determined with a simple configuration.

[0008] The present invention relates to an eyeglass lens manufacturing apparatus and an eyeglass lens manufacturing method, and more particularly to an eyeglass lens manufacturing method and an eyeglass lens manufacturing method.

[0009] Hereinafter, a spectacle lens manufacturing apparatus 10 and manufacturing method according to one embodiment of the present invention will be described with reference to the drawings.

[0010] First, the eyeglass lens manufacturing apparatus 10 of this embodiment will be described below.

[0011] Next, the manufacturing apparatus 10 manufactures eyeglass lenses by performing various processes on a transparent lens substrate L, and as shown in FIG. 1 , is equipped with a back-side cutting device 20 that cuts the lens back surface L2 side opposite the lens surface L1 of the lens substrate L, an imaging device 30 that images the lens substrate L, an outer edge state determination unit 40 that determines the shape of the lens surface outer edge L1a of the lens surface L1 of the lens substrate L based on the image obtained by the imaging device 30, an outer edge chamfering device 50 that chamfers the outer edge of the lens substrate L, and a polishing device 60 that polishes the lens back surface L2.

[0012] Each component of the manufacturing apparatus 10 will be specifically described below.

[0013] First, as shown in Fig. 2, the back surface cutting device 20 cuts the lens back surface L2 side of the lens substrate L formed as a semi-finished lens to form a shape that satisfies the prescription of the spectacle lens wearer. Note that the symbol Lr in Fig. 2 indicates the portion of the lens substrate L on the lens back surface L2 side that is removed by the back surface cutting device 20.

[0014] The imaging device 30 is installed downstream of the back surface side cutting device 20, and includes an imaging unit such as a CCD camera, and images the lens substrate L from a position away in the lens thickness direction, as shown in Fig. 2. In this embodiment, the lens substrate L is imaged from the lens back surface L2 side as shown in Fig. 2, but the lens substrate L may also be imaged from the lens surface L1 side.

[0015] Outer edge state determination unit 40 is a unit that determines the shape of the lens surface outer edge L1a of lens surface L1 of lens substrate L based on the image obtained by imaging device 30, and in this embodiment, it is a unit that extracts the lens surface outer edge L1a of lens surface L1 of lens substrate L based on the image obtained by imaging device 30, and determines whether or not chamfering of the outer edge of lens substrate L is necessary based on this lens surface outer edge L1a. Outer edge state determination unit 40 is equipped with a memory unit consisting of ROM, RAM, etc., an input unit, an output unit, a control unit consisting of a CPU, etc., a communication unit, an auxiliary storage device, etc., and the control unit is configured as a control terminal such as a personal computer that operates in accordance with software deployed in the memory unit.

[0016] When the outer edge condition determination unit 40 determines that the shape of the outer edge L1a of the lens surface is not circular, the outer edge chamfering device 50 chamfers the outer edge (edge) of the lens substrate L by cutting or grinding so as to remove the acute corner Le formed on the outer edge of the lens substrate L as shown in Figure 2 (b).

[0017] The polishing device 60 is installed downstream of the outer edge chamfering device 50 and polishes the lens back surface L2 of the lens substrate L. [Method of Manufacturing Spectacle Lenses]

[0018] Next, a method for manufacturing a spectacle lens using the manufacturing apparatus 10 of this embodiment will be described below.

[0019] The method for manufacturing eyeglass lenses includes, in order from the upstream side, a back-side cutting process for cutting the lens back surface L2 side of the lens substrate L; an imaging process for imaging the lens substrate L; an outer edge state determination process for determining the shape of the lens surface outer edge L1a of the lens surface L1 of the lens substrate L based on the image obtained in the imaging process; an outer edge chamfering process for chamfering the outer edge of the lens substrate L; and a polishing process for polishing the lens back surface L2.

[0020] Each step of the manufacturing method will be specifically described below.

[0021] First, the back surface cutting process involves using a back surface cutting device 20 to cut the lens back surface L2 of the lens substrate L into a shape that satisfies the prescription of the eyeglass lens wearer. As shown in Figure 2, the back surface cutting process is carried out with colored tape T attached to the lens surface L1 of the lens substrate L. In this embodiment, the colored tape T is attached over the entire surface of the lens surface L1 for the purpose of protecting the convexly curved lens surface L1, and in this embodiment, it is a translucent blue tape.

[0022] The imaging process is carried out after the back surface cutting process, and involves imaging the lens substrate L from a position away in the lens thickness direction using an imaging device 30, as shown in Fig. 2. The imaging process is carried out with the colored tape T described above attached to the lens surface L1 of the lens substrate L, as shown in Fig. 2.

[0023] The outer edge condition determination process involves the outer edge condition determination unit 40 determining the shape of the lens surface outer edge L1a based on the image obtained by the imaging device 30. In this embodiment, the lens surface outer edge L1a of the lens surface L1 of the lens substrate L is extracted based on the image obtained by the imaging device 30, and a determination is made as to whether or not chamfering of the outer edge of the lens substrate L is required based on the lens surface outer edge L1a.

[0024] Specifically, in the back-side cutting process, the lens substrate L is cut from the lens back surface L2 side. However, depending on the prescription of the spectacle lens wearer, the lens substrate L may be cut significantly, down to the lens surface L1, as shown in Fig. 2(b). In this case, the outer edge L1a of the lens surface L1, which was circular before cutting, becomes non-circular, as shown in Fig. 3(b). At this time, the colored tape T is also cut along with the lens surface L1, and the shape of the colored tape T becomes non-circular, just like the lens surface L1. Note that Figs. 2(a) and 3(a) show an example in which the lens surface L1 is not cut in the back-side cutting process, while Figs. 2(b) and 3(b) show an example in which the lens surface L1 is cut down to the lens surface L1 in the back-side cutting process.

[0025] When the lens substrate L is ground down to the lens surface L1 side, as shown in FIG. 2( b), an acute-angled corner (a so-called knife edge) Le is formed on part of the outer edge of the lens substrate L. When such an acute-angled corner Le is formed, the acute-angled corner Le will damage the polishing pad in the polishing step, which is a step downstream of the back surface cutting step. Therefore, it is desirable to remove the acute-angled corner Le by chamfering the outer edge of the lens substrate L prior to the polishing step, etc.

[0026] Therefore, the outer edge condition determination process of this embodiment solves the above-mentioned problem by extracting the lens surface outer edge L1a of the lens surface L1 of the lens substrate L based on the image obtained in the imaging process, and automatically determining whether or not chamfering of the outer edge of the lens substrate L is required based on the lens surface outer edge L1a.

[0027] Next, the determination method in the outer edge state determination step will be described in detail. First, in the outer edge state determination step of this embodiment, the color (blue) of the colored tape T affixed to the lens surface L1 is extracted from the image obtained in the imaging step shown in Fig. 3 and binarized (in this embodiment, the image obtained in the imaging step is converted into an RGB image, then converted into an HSV color coordinate system, and the hue is limited to the blue hue of the colored tape T used in this embodiment, and binarization is performed). This extracts the lens surface outer edge L1a by assuming that the outline of the colored tape T is the lens surface outer edge L1a. Next, based on the extracted lens surface outer edge L1a, an imaginary circumscribing circle Vc circumscribing the lens surface outer edge L1a is set as shown in Fig. 3. Outer edge distance information including the distance R from the center of the imaginary circumscribing circle Vc to the lens surface outer edge L1a is extracted at multiple locations on the lens surface outer edge L1a, i.e., at angular positions at a predetermined angular interval (e.g., 1° interval) circumferentially around the lens surface outer edge L1a. Next, the standard deviation of the distances R at multiple locations on the lens surface outer edge L1a is calculated, and if the calculated standard deviation is equal to or less than a predetermined threshold value, it is determined that the shape of the lens surface outer edge L1a is circular and that chamfering of the lens surface outer edge L1a is not necessary; if the standard deviation is greater than the threshold value, it is determined that the shape of the lens surface outer edge L1a is non-circular and that chamfering of the lens surface outer edge L1a is necessary.

[0028] In the outer edge chamfering process, when it is determined in the outer edge condition determination process that the shape of the lens surface outer edge L1a is non-circular and that chamfering of the lens surface outer edge L1a is necessary, the outer edge chamfering device 50 chamfers the outer edge of the lens substrate L so as to remove the above-mentioned acute corner portion Le.

[0029] The polishing step is a step of polishing the lens rear surface L2 of the lens substrate L using a polishing device 60 after the rear surface cutting step.

[0030] The eyeglass lens manufacturing apparatus 10 and manufacturing method of the present embodiment obtained in this manner include an imaging step of imaging the lens substrate L, and an outer edge state determination step of extracting outer edge distance information including the distance R from the center of an imaginary circumscribing circle Vc circumscribing the lens surface outer edge L1a to the lens surface outer edge L1a at multiple locations on the lens surface outer edge L1a of the lens substrate L based on the images obtained in the imaging step, and determining the shape of the lens surface outer edge L1a based on the outer edge distance information. This makes it possible to automatically and accurately determine the shape of the lens surface outer edge L1a (in the case of this embodiment, determine whether the shape of the lens surface outer edge L1a is circular), thereby eliminating the need for an operator to visually determine the shape of the lens surface outer edge L1a, thereby reducing the labor required and suppressing variation in the determination results.

[0031] Furthermore, in the imaging process, the lens substrate L is imaged with colored tape T attached to the lens surface L1, and in the outer edge state determination process, outer edge distance information is extracted assuming that the outline of the colored tape T is the lens surface outer edge L1a. This makes it possible to extract outer edge distance information well and accurately determine the shape of the lens surface outer edge L1a even when the lens substrate L is highly transparent (low colorability).

[0032] In addition, in the outer edge state determination process, the standard deviation of the distance R at multiple locations on the lens surface outer edge L1a is calculated, and if the calculated standard deviation is below a predetermined threshold, it is determined that the shape of the lens surface outer edge L1a is circular, thereby making it possible to accurately determine whether the shape of the lens surface outer edge L1a is circular based on the outer edge distance information.

[0033] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design modifications can be made without departing from the present invention as defined in the claims, such as configuring an eyeglass lens manufacturing apparatus 10 and manufacturing method by arbitrarily combining the respective configurations of the above or following embodiments and modified examples.

[0034] For example, in the above-described embodiment, the lens substrate L is described as a semi-finished lens, that is, a semi-finished lens that is a semi-finished product in which the shape of the lens front surface side, which has a convex curved surface (facing outward when worn) (a convex curved surface near the center) is in a completed state, and the shape of the lens back surface L2, which has a concave curved surface (facing the eyeball when worn) (a concave curved surface near the center), is processed in the above-described back surface cutting step to achieve a shape that satisfies the prescription of the eyeglass lens wearer, but the specific form of the lens substrate L is not limited to the above.

[0035] Furthermore, in the above-described embodiment, an image of the lens substrate L with colored tape T attached to the lens surface L1 is captured, and in the outer edge state determination process, outer edge distance information is extracted assuming that the outline of the colored tape T is the lens surface outer edge L1a. However, the method of extracting outer edge distance information is not limited to this, and it is also possible to capture an image of the lens substrate L with no colored tape T attached to the lens surface L1, extract the lens surface outer edge L1a of the lens surface L1 from the captured image, and extract the outer edge distance information.

[0036] The lens substrate L may have any refractive index, but the present invention is suitable for a lens substrate L having a refractive index of 1.5 or more.

[0037] REFERENCE SIGNS LIST 10 Manufacturing device 20 Back surface cutting device 30 Imaging device 40 Outer edge state determination unit 50 Outer edge chamfering device 60 Polishing device L Lens substrate L1 Lens surface L1a Lens surface outer edge L2 Lens back surface T Colored tape Lr Portion to be removed in back surface cutting process Le Acute-angled corner Vc Virtual circumscribed circle

Claims

1. A method for manufacturing an eyeglass lens, comprising: an imaging step of imaging a lens substrate; and an outer edge state determination step of extracting outer edge distance information including the distance from the center of a virtual circumscribed circle circumscribing the outer edge of the lens surface to the outer edge of the lens surface at a plurality of locations on the outer edge of the lens surface of the lens substrate based on the image obtained in the imaging step, and determining the shape of the outer edge of the lens surface based on the outer edge distance information.

2. The method for manufacturing an eyeglass lens according to claim 1, wherein in the outer edge state determination step, it is determined whether the shape of the outer edge of the lens surface is circular based on the outer edge distance information.

3. The method for manufacturing an eyeglass lens according to claim 2, further comprising an outer edge chamfering step of chamfering the outer edge of the lens substrate when it is determined in the outer edge state determination step that the shape of the outer edge of the lens surface is not circular.

4. The method for manufacturing an eyeglass lens according to claim 3, further comprising a polishing step of polishing the back surface of the lens of the lens substrate as a step performed after the outer edge chamfering step.

5. In the imaging step, the lens substrate with a colored tape attached to the lens surface is imaged, and in the outer edge state determination step, the outer edge distance information is extracted assuming that the contour of the colored tape is the outer edge of the lens surface. The method for manufacturing an eyeglass lens according to any one of claims 1 to 4.

6. The method for manufacturing an eyeglass lens according to claim 5, further comprising a back surface side cutting step of cutting the back surface of the lens substrate on the side opposite to the lens surface with a colored tape attached to the lens surface as a step performed before the imaging step.

7. In the outer edge state determination step, the standard deviation of the distances at a plurality of locations on the outer edge of the lens surface is calculated, and when the calculated standard deviation is equal to or less than a preset threshold value, it is determined that the shape of the outer edge of the lens surface is circular. The method for manufacturing an eyeglass lens according to any one of claims 1 to 6.

8. A method for manufacturing an eyeglass lens, comprising: an imaging step of imaging a lens substrate; and an outer edge state determination step of extracting the outer edge of the lens surface of the lens substrate based on the image obtained in the imaging step, and determining the necessity of chamfering the outer edge of the lens substrate based on the outer edge of the lens surface.

9. An apparatus for manufacturing spectacle lenses, comprising: an imaging device that images a lens substrate; and an outer edge state determination unit that extracts outer edge distance information including the distance from the center of a virtual circumscribed circle circumscribing the outer edge of the lens surface to the outer edge of the lens surface at a plurality of locations on the outer edge of the lens surface of the lens substrate based on an image obtained by the imaging device, and determines the shape of the outer edge of the lens surface based on the outer edge distance information.

10. An apparatus for manufacturing spectacle lenses, comprising: an imaging device that images a lens substrate; and an outer edge state determination unit that extracts the outer edge of the lens surface of the lens substrate based on an image captured by the imaging device, and determines whether chamfering of the outer edge of the lens substrate is necessary based on the outer edge of the lens surface.

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