Method for manufacturing optical articles

Abstract

The invention relates to a method for manufacturing an optical article (30), comprising the following steps: S1) providing at least two different components (10), each component having two end faces (11, 12); s2) assembling the at least two components such that their end faces (11, 12) form the main faces (21, 22) of the component assembly (20); and S3) machining at least one of the main surfaces to generate at least one optical surface of the optical article.

Description

Technical Field

[0001] This invention generally relates to the field of eyeglasses.

[0002] More specifically, the present invention relates to a method for manufacturing an optical article (such as an ophthalmic lens) to be mounted in an eyeglass frame. Background Technology

[0003] A traditional method for manufacturing ophthalmic lenses includes:

[0004] - Two molded housings are provided, with annular closure members (e.g., sealing strips) around the periphery of the two molded housings, which, together with the housings, define a molding cavity.

[0005] - A lens blank is molded by filling the molding cavity with a monomer and by polymerizing the monomer into a polymer.

[0006] - The two surfaces of the blank are machined to obtain a lens that achieves its designed optical function.

[0007] These two molded housings are used to mold several lens blanks, thereby producing lenses with different shapes.

[0008] The shape difference between the lens blank and the resulting machined lens is usually significant. In fact, the blank must be thick enough to be used to manufacture lenses of various shapes.

[0009] In other words, molding lens blanks requires a large amount of material. Furthermore, a significant amount of material must be removed during the machining process. It is not uncommon for the weight of a lens blank to be five times that of the finished lens.

[0010] Using smaller blanks can avoid this problem, but this solution would require a large number of molded shells of different shapes, which is difficult to manage in practice. Summary of the Invention

[0011] Against this backdrop, the present invention provides a novel method for manufacturing optical articles that minimizes the amount of manufacturing materials required and the amount of material to be removed during machining steps.

[0012] More specifically, the present invention relates to a method for manufacturing optical articles, the method comprising the following steps:

[0013] S1) Provide at least two different components, each component having two end faces and at least one side face.

[0014] S2) Assemble the at least two components via their sides, such that their end faces form the main face of the component assembly (i.e., the lens blank), and

[0015] S3) Machining at least one of the main surfaces to form at least one optical surface of the optical article.

[0016] Therefore, the lens blank is not formed from a single part by molding, but from individual parts assembled edge-to-edge (their sides contact each other). Thus, each part can be designed to have the smallest possible size.

[0017] Therefore, thanks to this invention, the amount of material required to form a lens blank is far less than that required to mold a lens blank as a single component, which is both cost-effective and environmentally friendly. Furthermore, it reduces the amount of material to be removed during the machining process, allowing this step to be performed faster and at a lower cost due to less tool damage.

[0018] Other preferred features of the present invention are as follows:

[0019] - The optical surfaces are the front and back of the optical article (opposite to each other).

[0020] - The one or more sides extend between the end faces.

[0021] - Step S3) includes: machining the two main surfaces to form the two optical surfaces of the optical article;

[0022] - The assembly step S2) includes: positioning the at least two components relative to each other; and joining the at least two components together;

[0023] - The at least two components are made of a material having a first refractive index and are bonded together by means of an adhesive having a second refractive index, the ratio of the second refractive index to the first refractive index being between 83% and 100%;

[0024] - In the variant, the at least two components are joined together by melting.

[0025] - The end faces of each component are parallel;

[0026] - The two components have different lengths, each measured between the end faces of the components;

[0027] - The providing step S1) includes sub-step S11): calculating the length of each component based on the desired shape of the optical surface of the optical article;

[0028] - Each length is calculated such that at least one point on each end face of the component is located on one of the optical surfaces of the optical article, or at a distance from the optical surface less than a predetermined threshold.

[0029] - At least two components have the same cross-section in a plane orthogonal to the axis passing through the two end faces of one of the components;

[0030] - All components have the same cross-section;

[0031] - The at least two components have different cross sections in a plane orthogonal to the axes passing through the two end faces of one of the components;

[0032] - One component has a circular shape, and at least one other component has an annular shape;

[0033] - One component has a recess, and another component has a protrusion that engages with the recess during assembly step S2);

[0034] - The providing step S1) includes sub-step S12): manufacturing at least one part by additive manufacturing, molding, or cutting a template;

[0035] - The at least two components have different refractive indices;

[0036] - The optical product in question is an ophthalmic lens;

[0037] - The at least two components perform different optical functions. For example, one of these components may include microlenses (such as those described in document WO 2019166654), a diffuse / scattering surface or element, a specific coating, or a color filter.

[0038] It should be noted that the following features may be employed in a single embodiment:

[0039] - The components are joined together by melting.

[0040] - One component has a circular shape, and at least one other component has an annular shape, and

[0041] - The providing step S1) includes sub-step S11): calculating the length of each component based on the desired shape of the optical surface of the optical article.

[0042] In addition, these features collectively address a single technical problem: minimizing the amount of manufacturing material required (no glue, no useless material) and minimizing the amount of material to be removed during machining steps.

[0043] The present invention also relates to an optical article having two optical surfaces and comprising at least two different and assembled components, each component having two end faces that form the optical surfaces. Detailed Implementation

[0044] The following description, with reference to the accompanying drawings and by way of non-limiting examples, makes clear the scope of the invention and the ways in which it may be practiced.

[0045] In the attached diagram:

[0046] - Figure 1 This is a schematic diagram of a lens blank and a lens manufactured according to the present invention;

[0047] - Figure 2 yes Figure 1 A schematic front view of a lens blank and variations thereof;

[0048] - Figure 3 It shows the relationship with Figure 1 A cross-sectional view of the lens blanks stacked together by the manufactured lenses;

[0049] - Figure 4 yes Figure 1 A schematic front view of a component of another variant of the lens blank;

[0050] - Figure 5 yes Figure 1 A schematic diagram of another variant of the lens blank;

[0051] - Figure 6 yes Figure 1 A schematic diagram of another variant of the lens blank;

[0052] - Figure 7 The illustration shows the method according to the present invention. method

[0053] Figure 7 A method for manufacturing optical articles 30 is demonstrated.

[0054] The optical component 30 can have any shape.

[0055] exist Figure 1 In the embodiment shown on the right side, the optical article is an ophthalmic lens, such as a single-vision lens, a myopia control lens, a progressive multifocal lens, or a bifocal or trifocal lens. This lens is suitable for mounting in the rim of an eyeglass frame. However, in variations, the optical article 30 may be a sunglasses lens (tinted or untinted, polarized or non-polarized), a lens suitable for mounting in goggles, a lens for optical devices (microscope lenses, telescope lenses), etc.

[0056] The manufacturing method according to the present invention comprises three main steps.

[0057] The first step S1) includes providing at least two different parts (hereinafter referred to as “lens blank part 10” or “part 10”), each part having a side and two end faces 11, 12.

[0058] The second step S2) includes assembling the at least two lens blank components 10 (hereinafter referred to as "lens blank 10") such that their end faces 11, 12 form the main faces 21, 22 of the lens blank. In this step, the components 10 are assembled side-to-side through their sides.

[0059] The third step (S3) includes machining one and / or the other of the main surfaces 21 and 22 to form the optical surface of the optical article 30.

[0060] Many different embodiments are possible.

[0061] Firstly, it can be based on Figures 1 to 3 These steps will be described in detail by describing a first embodiment of the invention. - S1

[0062] In this embodiment, the first step S1 includes providing a plurality of different components 10 that extend along the main axis A1.

[0063] In one embodiment, all components have the same refractive index. These components are all made of the same material.

[0064] In a preferred embodiment, the cross-section of each component 10 (in a cross-sectional plane orthogonal to the principal axis A1) has a constant shape, regardless of the position of the cross-sectional plane along the principal axis A1. In other words, all components 10 have cylindrical side surfaces.

[0065] The end faces 11, 12 of each component 10 are flat and orthogonal to the main axis A1 of the component.

[0066] At least two of these components 10 have the same cross-section.

[0067] In the illustrated embodiment, these components all have the same cross-section. These cross-sections are all hexagonal in shape.

[0068] Therefore, each component can be surrounded by six other identical components 10.

[0069] like Figure 2 As clearly shown in the left-hand diagram, there is a central component 10 surrounded by six first components, twelve second components surrounding these first components, and twelve final components distributed around the second components. In other words, these components (except for the central component) are distributed along coaxial circles with different diameters.

[0070] The number of components used depends on the diameter of the optical component 30 to be manufactured. This number is chosen to be as small as possible.

[0071] For this purpose, Figure 2 In the diagram on the right, these different components are distributed in different ways. In this configuration, there are three central components, and the other components are distributed in layers around these three central components.

[0072] The goal in both cases is that, once the component is assembled along its sides, it forms an assembly (lens blank 20) ​​covering a circular surface without any openings. The circle C1 defining this surface corresponds here to the diameter of the optical article 30 to be manufactured.

[0073] In the following text, components 10 will be considered as mounted adjacent to each other on a flat support 100 during their assembly, such that their main axes A1 extend vertically, and that the front main surface 21 of the lens blank 20 is supported against the support 10 (see [link to documentation]). Figure 3 ).

[0074] Therefore, the concept of “height” will be used below to define the distance between a point, axis, or plane and the support 100.

[0075] Each component 10 may have the same length and be distributed at different heights relative to the support 100.

[0076] However, preferably, at least two of the components 10 have different lengths. In fact, the aim is to ensure that the shape of the lens blank 20 after machining is as close as possible to the shape of the optical article 30.

[0077] Therefore, step S1 includes a first sub-step S11 for calculating the ideal length of each component 10 and a sub-step S12 for manufacturing these components.

[0078] exist Figure 3 In the image, a cross-sectional view of a portion of the lens blank 20 (with its two main surfaces 21, 22) is shown, which is virtually superimposed on a view of a portion of the machined optical article 30 (with its two optical surfaces 31, 32).

[0079] The figure shows a central component 10 with length L1, two adjacent components 10 with length L2 located on each side of the central component 10, and two peripheral components 10 with length L3.

[0080] It can be observed that if the lower end faces 11 of the central component and adjacent components 10 are at the same height from the support 100, the lower end faces of the peripheral components are not, but are offset upwards. For this reason, shims of the desired height can be inserted between these lower end faces 11 and the support 100.

[0081] Of course, to facilitate the manufacture of lens blanks, all lower end faces can be arranged at the same height. Therefore, when assembling component 10, these components can be placed directly on the flat support 100. However, this variation is not preferred because it would require a much larger amount of material to manufacture the optical article 30.

[0082] exist Figure 3 Further observation revealed that the upper surfaces 12 of the central component, adjacent components, and peripheral components are all located at different heights.

[0083] Therefore, sub-step S11 includes operations for obtaining the 3D shape of the optical surfaces 31, 32 of the optical article 30.

[0084] Then, this sub-step includes the operation of virtually distributing the components 10 relative to the 3D shape to minimize the number of components required to manufacture the optical article 30 (as described above based on...). Figure 2 (As explained).

[0085] The sub-step also includes the following steps: calculating the lengths L1, L2, and L3 of component 10 such that the end faces 11 and 12 of component 10 are completely located on each side of the optical surfaces 31 and 32 of optical article 30.

[0086] Preferably, it is planned that there be a non-zero gap between the end faces 11, 12 of the component 10 and the optical surfaces 31, 32 of the optical article 30 (in the above virtual distribution), so that the entire main surface 21, 22 of the lens blank 20 can be machined. This gap is, for example, chosen to be between 0.1 mm and 1 mm.

[0087] In other words, the calculation operation is performed such that the length of each component 10 is greater than or equal to (preferably strictly greater than) the expected maximum thickness in the region where the component of the optical article 30 is located (the maximum thickness is considered to be equal to the height difference between the highest point of the upper optical surface 32 and the lowest point of the lower optical surface 31 in that region).

[0088] The final operation will include calculating the thickness of the gaskets required to hold the different components 10 together.

[0089] During sub-step S12, different parts 10 are manufactured. This can be done in quite different ways.

[0090] Typically, component 10 can be manufactured by molding. In this case, different molds are used to manufacture components 10 with different lengths. In this embodiment, the mold selected for manufacturing the component is one that allows the length of the component to be as close as possible, but is generally larger than the calculated length.

[0091] Alternatively, component 10 can be made from a bar with a desired cross-section by cutting the bar to a desired length. The bar itself can be obtained by molding.

[0092] Still as a variant, part 10 can be produced by additive manufacturing (e.g., using a 3D printer). In fact, some additive manufacturing methods can be performed on objects smaller than optical article 30 but larger than part 10. This manufacturing method can be used in this context.

[0093] The materials used to manufacture the parts are the same as known materials (glass, polycarbonate, etc.). - S2

[0094] During step S2), the components are assembled and secured together.

[0095] Different fixing methods can be used. Typically, these components can be fixed by melting, for example, using a laser in this regard.

[0096] In a variant, certain adhesives may be used to attach the components 10 to each other. In this variant, the aim is to ensure that the adhesive does not create visible gaps between the components 10. For this purpose, the adhesive will be selected such that its refractive index is equal to or slightly lower than the refractive index of the components 10. In a preferred embodiment, the ratio of the refractive index of the adhesive to the refractive index of the components 10 is between 83% and 100%.

[0097] Figure 4 A variant is shown in which components 10A and 10B are equipped with interlocking devices to ensure better assembly (increased mating surface). On at least one component 10B, these interlocking devices include a protrusion 18 adapted to engage with a recess 19 provided in the other component 10A.

[0098] In this variant, when components 10 are manufactured by molding or by cutting bar stock, these components preferably all have the same cross-section. For example, each component 10 has one, two, or three protrusions distributed on its six sides and correspondingly one, two, or three cavities. If components 10 are manufactured by cutting bar stock, these protrusions and cavities will extend over the entire length of each component 10. When components 10 are manufactured by additive manufacturing, a different approach can be taken, for example, providing protrusions and cavities only where they are considered most useful (e.g., on the periphery of the lens blank), and they can be provided only for a portion of the length of each component. - S3

[0099] During step S3, the two main surfaces 21 and 22 of the machined lens blank 10 are machined.

[0100] This machining concept may involve surface treatment, that is, removing a large amount of material (e.g., more than 0.1 mm) from at least one area of ​​the lens blank 20 to machine the main surfaces 21, 22.

[0101] Alternatively, or as a variation, machining may include polishing these main surfaces 21, 22 with a tool having a particle size of less than 3 µm.

[0102] Preferably, a surface treatment operation is performed on each of the two main surfaces 21, 22 of the lens blank 22, followed by a polishing operation. However, as a variation, ideally, when the part 10 is manufactured by additive manufacturing, only one of the two main surfaces 21, 22 of the lens blank 20 may be machined, while the other has an intact surface condition.

[0103] In any case, the resulting optical article 30 is formed from different components 10, which are rigidly fixed to each other and arranged so that the lens can fulfill the optical function it is designed for.

[0104] The edge of the optical component 30 can then be machined to achieve a circular profile. Alternatively, the edge can be directly machined into the shape of the lens rim profile. Other embodiments

[0105] This invention is by no means limited to Figures 1 to 4 The embodiments described and illustrated.

[0106] For example, the component 10 used to manufacture an optical article 30 can be formed from different materials or can be manufactured according to different methods.

[0107] As a first example, if the lens to be manufactured is a progressive multifocal lens, components with different refractive indices can be used to form the distance and near vision zones of the lens. Thanks to this arrangement, progressive multifocal lenses with small thicknesses can be designed.

[0108] As a second example, some of these components may have a front end face with a flat or convex shape, while others may have a front end face with several concave and convex features. The first components will be arranged at the center of the lens and along the lens's contour, while the other components will be arranged in a circle between these first components. This lens will be designed to alter the natural evolution of optical defects (in this case, myopia). Such concave and convex features with microlens functionality are described, for example, in document WO 2019166654.

[0109] Figure 5 Another embodiment is shown. In this embodiment, some components 10C, 10D, 10E, and 10F of the lens blank 20A have different shapes, depending on whether the component is located around the center of the lens (in which case the cross-section of the component is triangular), on the first ring around these triangular components (the cross-section of the component is trapezoidal), or on subsequent rings (the cross-section of the component is still trapezoidal, but the width increases).

[0110] Figure 6 Another embodiment is shown. In this embodiment, all components 10 of the lens blank 20B have cross-sections with different shapes.

[0111] Here, the central component 10G has a circular shape; the intermediate component 10H has an annular shape, and its opening is closed by the central component 10G; and the outer component 10J has an annular shape, and its opening is closed by both the central component 10G and the intermediate component 10H.

[0112] In this embodiment, the refractive index of the intermediate component 10H can be, for example, slightly higher than that of the central component 10G, and the refractive index of the outer component 10J can be slightly higher than that of the intermediate component 10H. The opposite is also conceivable. Thanks to this arrangement, lenses with small thicknesses can be designed.

Claims

1. A method for manufacturing an optical article (30), the method comprising the following steps: S1) Provide at least two different parts (10), each part having two end faces (11, 12) and at least one side face. S2) Assemble the at least two components (10) by means of their side faces, such that their end faces (11, 12) form the main faces (21, 22) of the component (10) assembly (20), and S3) Machining at least one of the main surfaces (21, 22) to form at least one optical surface (31, 32) of the optical article (30).

2. The method according to claim 1, wherein, Step S3) includes machining the two main surfaces (21, 22) to form the two optical surfaces (31, 32) of the optical article (30).

3. The method according to claim 1 or 2, wherein, The assembly step S2) includes: positioning the at least two components (10) relative to each other; and joining the at least two components (10).

4. The method according to claim 3, wherein, The at least two components (10) are made of a material having a first refractive index and are bonded together by means of an adhesive having a second refractive index, the ratio of the second refractive index to the first refractive index being between 83% and 100%.

5. The method according to claim 3, wherein, The at least two components (10) are joined together by melting.

6. The method according to any one of claims 1 to 5, wherein, The end faces (11, 12) of each component (10) are parallel.

7. The method according to any one of claims 1 to 6, wherein, The two components (10) have different lengths (L1, L2, L3), each length being measured between the end faces (11, 12) of the components (10).

8. The method according to claim 7, wherein, The provision step S1) includes sub-step S11): calculating the length (L1, L2, L3) of each component (10) based on the desired shape of the optical surfaces (31, 32) of the optical article (30).

9. The method according to claim 8, wherein, Each length (L1, L2, L3) is calculated such that at least one point of each end face (11, 12) of the component (10) is located on one of the optical surfaces (31, 32) of the optical article (30), or at a distance less than a predetermined threshold from the optical surface.

10. The method according to any one of claims 1 to 9, wherein, The at least two components (10) have the same cross section in a plane orthogonal to the axes of the two end faces (11, 12) of one of the components (10).

11. The method according to any one of claims 1 to 9, wherein, The at least two components (10C, 10D, 10E, 10F) have different cross sections in a plane orthogonal to the axes of the two end faces (11, 12) of one of the components (10C, 10D, 10E, 10F).

12. The method according to claim 11, wherein, One component (10G) has a circular shape, and at least one other component (10H, 10J) has an annular shape.

13. The method according to any one of claims 1 to 12, wherein, One component (10A) has a recess and another component (10B) has a protrusion that engages with the recess during the assembly step S2).

14. The method according to any one of claims 1 to 13, wherein, The providing step S1) includes sub-step S12): manufacturing at least one part (10) by additive manufacturing or by molding or by cutting a template.

15. The method according to any one of claims 1 to 14, wherein, The at least two components (10) have different refractive indices.

16. The method according to any one of claims 1 to 15, wherein, The at least two components (10) perform different optical functions.

17. An optical article (30) having two optical surfaces (31, 32) and comprising at least two different and assembled components (10), each component (10) having two end faces (11, 12), the end faces (11, 12) of the component (10) forming the optical surfaces (31, 32).

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