Manufacturing method of eyeglass lenses

Abstract

The invention relates to a method for manufacturing a spectacle lens comprising a base and a number of solid optical elements (20) embedded in the base, the solid optical elements having refractive properties different from those of the base, comprising the steps of: - providing the solid optical elements and a first part (11) of the base; - arranging the solid optical elements (20) inside the first part of the base; - manufacturing a second part of the base inside and to the solid optical elements to obtain the spectacle lens.

Description

[Technical field]

[0001] The present invention relates generally to the field of eyewear.

[0002] More specifically, the present invention relates to a method for manufacturing a spectacle lens that includes a base and a plurality of optical elements embedded in the base, the optical elements having refractive properties different from those of the base. [Background technology]

[0003] Myopia is characterized by the eye (in distance vision) imaging distant objects at a non-zero distance in front of the retina. Myopia is usually corrected with concave lenses.

[0004] It has been found that some people's (especially children's) eyes corrected with such lenses image inaccurately when viewing objects located at close range (near vision).

[0005] Due to this imaging defect, the image of an object is formed behind the person's retina, and such imaging defect may affect the progression of myopia in such a person, and it is therefore known that for the majority of said persons, the myopic defect is likely to increase over time.

[0006] Furthermore, myopia has been increasing worldwide in recent years and has become a serious social problem. For example, in East Asia, myopia may affect up to 80% of the population.

[0007] In this context, many techniques have been developed to prevent or slow the progression of myopia, and among these techniques, some methods based on special corrective glasses have been reported to be effective.

[0008] For example, the document EP 3730997 discloses a lens comprising a body having a standard refractive power (based on the individual's prescription) and a number of microlenses having an optical function of not focusing on the retina of the eye in order to slow the progression of myopia.

[0009] The microlenses are contained within a body. Summary of the Invention [Problem to be solved by the invention]

[0010] For this purpose, a first part of the body is molded. Then, a dispenser is used to drop a resin material onto a number of predetermined locations on the body. After the resin material has hardened to form the microlenses, a second part of the body is molded into the microlenses.

[0011] The main drawback of the above solutions is the difficulty of producing microlenses with the exact required characteristics. [Means for solving the problem]

[0012] In this situation, the present invention provides a new solution for lens manufacturing.

[0013] More specifically, the present invention is directed to a method for manufacturing a spectacle lens comprising a base and a plurality of solid optical elements embedded in the base, the solid optical elements having refractive properties different from those of the base, the method comprising the steps of: - providing the solid optical element and a first portion of the base; - disposing the solid optical element inside a first portion of the base; - manufacturing a first portion of a base and a second portion of said base inside said solid optical element to obtain said spectacle lens.

[0014] The present invention allows solid (i.e. non-liquid) optical elements to be manufactured adjacent to one another at a distance from the base, so that these optical elements can be shaped to provide the exact optical properties required, and the resulting spectacle lenses are therefore manufactured as precisely as possible to prevent or slow the progression of myopia.

[0015] Other preferred features of the present invention are as follows: - at least two of said solid optical elements have different refractive properties; - at least one of said solid optical elements has a non-null cylindrical power; - the positioning step comprises the step of adhering a solid optical element to the inside of the first portion of the base, e.g. to the inner annular contour, - the bonding is carried out with the aid of an adhesive material, - applying an adhesive material (such as that described above) to the inside of the first portion of the base or to a surface of each solid optical element prior to the positioning step; - the adhesive material is polymerizable; - said adhesive material is polymerized prior to said manufacturing step; - the solid optical element is stacked on the inside one by one with at least one group of solid optical elements, - the adhesive material located between the last deposited group and said inner side is polymerized before another group is deposited on said inner side, - each group contains only one solid optical element; - the adhesive material is applied to the inside along an annular contour; - said first portion is a front portion of a spectacle lens and said inner portion is a back side of said front portion; - the manufacturing step includes molding a second portion of the base with a molding assembly; - the forming assembly includes a forming shell having the same diameter as the first portion, and a tape wrapped around a periphery of the forming shell and the first portion to maintain the first portion and the forming shell at a non-null distance from each other, the inside of the first portion facing the forming shell; - the method includes the step of removing the spectacle lens from the molding assembly after said manufacturing step; - forming the first portion prior to said providing step; - prior to said providing step, molding said solid optical element.

[0016] The following description, with reference to the accompanying drawings given as non-limiting examples, clarifies the components of the invention and how it can be put into practice. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a schematic diagram of a first step in the manufacturing process of a first portion of a spectacle lens according to the invention. [Diagram 2] FIG. 4 is a schematic diagram of a second step in the manufacturing process of the first portion of the eyeglass lens. [Diagram 3-4] 3 is a schematic diagram of a third step of the manufacturing process during which a first portion of the spectacle lens contains a microlens. FIG. [Diagram 5] 5 is a partial cross-sectional view of a first portion of the eyeglass lens shown in FIG. 4. [Figure 6] 5 is a side view of a first portion of the spectacle lens and a molding shell shown in FIG. 4. [Figure 7] FIG. 1 is a schematic diagram of a molding assembly used in manufacturing eyeglass lenses. [Figure 8] FIG. 2 is a schematic diagram of a spectacle lens in the final step of the manufacturing process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention relates to spectacle lenses, and herein to spectacle lenses that are designed to be cut to fit into a frame to be worn in front of the eye of an individual (hereinafter referred to as the "wearer").

[0019] In the context of the present invention, the term "lens" preferably refers to an uncut optical lens, which is not necessarily finished in the sense that it may further be covered by a finishing layer (anti-fog coating, anti-reflective coating...).

[0020] In the remainder of this specification, the terms "front side" and "back side" are used and should be understood in the context of how the lens is worn: in other words, while the lens is worn, the back side of the element faces the corresponding eye of the wearer and the front side faces in the opposite direction.

[0021] In the following description, reference is made to refractive or corrective power.

[0022] Such power of a corrective spectacle lens (or a part thereof) is defined by its spherical, cylindrical and prismatic refractive properties. It will be understood that such an optical definition is more general in scope than a surface-only definition. It defines the total refractive effect of a lens (or a part thereof) on an incident ray of light, resulting from the algebraic sum of the refractions caused successively by both the front and back sides of the lens.

[0023] Of these refractive properties, the first to be defined is the "spherical power" of the lens for an incident beam passing through it. It is defined as the degree of characterization and quantification of the main effect of the spherical refractive index of the lens (the "magnifying glass" effect) on the beam under examination. If it is a positive value, the lens has a converging effect on the beam, if it is a negative value, the effect on the beam is diverging. The point of the lens where the magnifying glass effect is zero (i.e., the point where the incident and transmitted rays have the same axis for a lens with a perfectly spherical power) is called the optical center. The axis perpendicular to the front surface of the lens and passing through this point is called the principal axis A1.

[0024] The term "cylindrical power" of a lens is defined as the degree of characterization and quantification of the cylindrical refraction effect produced by the lens for an incident light ray passing through it (also called cylinder power), which results in the formation of not one but two focal regions located in different planes, which are generally perpendicular to each other and are called the tangent and sagittal focus. The cylindrical power is also called "cylindrical power" or simply "astigmatism" and corresponds to the difference in the spherical power associated with the two focal regions. The two regions are distinguished by an axis passing through their respective "optical centers", commonly called the cylinder axis.

[0025] Finally, the "prismatic power" of a lens is defined as the degree of characterization and quantification of the prismatic refraction effect on an incident light ray passing through the lens (also known as the prismatic power), or more simply, the polarization caused by the lens on the light ray under examination. The prismatic power in question, also called "prism", corresponds to the angle at which the light ray is deflected, i.e. the angle formed between the entry point and the exit point of the light ray. The prism is composed of two components: a horizontal component called "horizontal prism", which corresponds to the angle formed between the projection of the entry point and the exit point of the light ray on a horizontal plane, and a vertical component called "vertical prism", which corresponds to the angle formed between the projection of the entry point and the exit point of the light ray on a vertical plane.

[0026] The following discussion is divided into two parts.

[0027] First, the spectacle lens to be manufactured will be described, followed by a description of the manufacturing process of the lens.

[0028] The eyeglass lens 10 to be manufactured is shown in FIG.

[0029] Here, the lenses are specifically designed to counteract the natural progression of optical defects, such as myopia.

[0030] The spectacle lens 10 includes a first optically refractive zone for correcting the wearer's vision at a predetermined distance and a second optically refractive zone for countering the natural progression of optical defects.

[0031] The first light-refractive region is at the center of the lens and the second light-refractive region completely surrounds the first light-refractive region.

[0032] The first optical refraction includes, for example, a spherical power that corrects the wearer's distance vision (for viewing objects located farther than 6 meters). The first optical refraction may also include a cylindrical and / or prismatic power.

[0033] The second refraction provides an additional optical feature, which is specifically designed to prevent or limit or arrest the progression of myopia.

[0034] For this purpose, the spectacle lens 10 used comprises a number of solid optical elements in the form of lenslets embedded in the remaining part of the spectacle lens 10, hereafter referred to as base 13.

[0035] It should be noted that a variety of lenslets may be used, including spherical, aspheric, plano-convex, bi-convex, polygonal, etc.

[0036] The lenslets may each have a contour shape that is inscribed within a circle having a diameter of at least 0.5 micrometers (μm) and no more than 1.5 millimeters (mm).

[0037] More specifically, the lenslets may be microlenses.

[0038] Here, the microlens 20 has the optical function of not forming an image on the retina of the eye in order to slow down the progression of abnormal refraction of the eye.

[0039] These structures can provide optical wavefront modification in intensity, curvature, or light deflection, where the wavefront intensity is configured such that the structures are absorptive and can locally absorb the wavefront intensity in the range of 0% to 100%, the curvature is configured such that the structures can locally modify the wavefront curvature in the range of ±20 diopters, and the light deflection is configured such that the structures can locally scatter the light at angles in the range of ±1° to ±30°.

[0040] Each microlens 20 is preferably made of a material that is distinct from the material of the base 13. The lenses are distinct in the sense that their respective refractive indices differ from one another.

[0041] All of the microlenses 20 may be identical. In this embodiment, they all have non-null spherical power.

[0042] However, in a preferred embodiment, some of the microlenses 20 are different from the others: in particular, at least one of the microlenses exhibits a different spherical power than another of the microlenses.

[0043] In a preferred embodiment, at least one of said microlenses exhibits a non-null cylindrical power.

[0044] It should be noted that at least one of the microlenses may be made of a material having a refractive index different from the refractive index of another one of the microlenses.

[0045] In other words, the spectacle lens 10 is - a transparent base 13 (body) designed to have a first refractive power based on a prescription that corrects the anomalous refraction of the wearer's eye; It includes a plurality of transparent solid microlenses 20 having optical properties different from those of the base 13.

[0046] The term "prescription" is understood to mean a set of optical characteristics of power, astigmatism and prism deviation determined by an ophthalmologist or optometrist to correct a vision defect of the eye. For example, a prescription for a myopic eye contains values ​​of powers (sphere, cylinder and prism) with an astigmatism axis. In the following, the base 13 of the spectacle lens 10 is considered to have only a spherical refractive power.

[0047] Such a spectacle lens 10 is described in more detail in the patent document WO 2019166654.

[0048] The manufacturing process for the spectacle lens 10 is described in more detail below. The process is carried out in five successive steps.

[0049] During this process, the main body 13 is manufactured in two parts 11 and 12 (actually two layers) that sandwich the microlens 20.

[0050] During the first step, the manufacturer orders or manufactures the first portion 11 of the base 13 and the microlenses 20 .

[0051] Here, the first part 11 of the base is formed by part of the thickness of the spectacle lens 10 .

[0052] Here, the first portion 11 is a front side portion of the spectacle lens 10. Thus, a front side 11F of the first portion 11 forms the front side of the spectacle lens, and a back side 11R (or inner side) is covered by the other portion 12 of the base 13.

[0053] The microlens 20 is solid at the end of this step in the sense that its shape does not change during the manufacture of the spectacle lens 10 and can therefore be defined as a finished microlens.

[0054] In a first example, the first portion 11 and the microlens 20 can be molded.

[0055] In this example, the microlenses are ordered from an outside supplier and the first portion 11 is molded in-situ.

[0056] For this purpose, a molded assembly is selected having an internal cavity adapted to the customer's prescription, the aim being to fill said molded assembly so as to obtain a first portion 11 having a thickness determined as a function of the shape of the front side 11F and the wearer's prescription (see FIG. 1).

[0057] In one variant, the first portion 11 may be shaped as a spherical plano lens, ie a lens with no optical power.

[0058] The second step, shown in FIG. 2, involves applying an adhesive material to the backside 11R of the first portion 11 of the base 13 or to the front side of each microlens 20.

[0059] Here, the embodiment used involves covering with an adhesive material the second optically refractive area on the back side 11R of the first portion 11. This embodiment is preferred because it is easy to implement.

[0060] The adhesive material is selected to be capable of securing the microlens 20 to the first portion 11 during the third and fourth steps of the process (described below).

[0061] The material is now polymerizable and contains, for example, a UV initiator of the "CGI1850" type (for example a mixture of 50% each of BAPO and IRGACURE® 184).

[0062] For example, the material 15 is applied to an annular region centered on the primary axis A1, as shown in Figure 2. Microlenses 20 are actually distributed in the region at a fixed distance from the optical center of the lens (the center of the lens that the wearer uses to see distant objects).

[0063] The third step, shown in FIG. 3, involves disposing a microlens 20 on the back side 11R of the first portion 11 of the base 13.

[0064] Each microlens 20 has a surface to be bonded to the back side 11R (which is concave), which may be a flat or convex surface. In a preferred embodiment, the radius of curvature of the front side of the microlens 20 is equal to the radius of curvature of the back side 11R of the first portion 11.

[0065] During this step, the microlenses 20 are for example first distributed along an inner circle centered on the main axis A1, and then distributed along another circle concentric with the latter, as shown in FIGS.

[0066] The microlenses are arranged to eventually form a network. The microlenses may have a periodic or quasi-periodic layout, but may also have randomized positions. Other exemplary layouts of the microlenses may be a grid or honeycomb layout with a constant grid step.

[0067] The distance between the microlenses may range from 0 (contiguous) to 3 times the structure (distinct microlenses). The microlenses 20 form discontinuous optical elements.

[0068] The distribution of the microlenses is advantageously carried out by an apparatus having a support for fixing the first portion 11 and a head movable relative to the support for picking up the microlenses 20 one by one and depositing them on the first portion 11.

[0069] It can be seen that the microlenses may differ from one another depending on their location on the first portion 11. For example, the microlenses 20 may have a different spherical power for each circle.

[0070] In this step, the microlenses can be held in place by a non-polymerized adhesive material (see FIG. 5).

[0071] The adhesive material is then polymerized.

[0072] More specifically, the material may be polymerized after some or all of the microlenses have been deposited in the first portion 11 .

[0073] However, in a preferred variant, the material is polymerised area by area with a short UV flash at the interface of the last deposited microlens and the first part 11 after each deposition of a microlens on the first part.

[0074] Here, the output of the UV flash is 20-60mWcm -2 It is.

[0075] This polymerization permanently bonds the microlens 20 to the first portion 11 and prevents it from moving any further.

[0076] A fourth step involves manufacturing the second part 12 of the base 13 on the rear side 11R of the first part 11 and on said microlens 20 to obtain said spectacle lens 10.

[0077] The second portion 12 may be manufactured by additive manufacturing.

[0078] However, in a preferred embodiment, second portion 12 is molded directly onto first portion 11 by a molding assembly 30 (see FIG. 7).

[0079] The mold assembly 30 may include a single molded shell 31 and tape 32. The first portion 11 may act as such a molded shell, eliminating the need for a separate molded shell.

[0080] Here, it can be seen that the first portion 11 thus presents a cylindrical periphery 11E (see FIG. 6).

[0081] The molded shell 31 is selected to have a cylindrical periphery 31E of the same diameter as the diameter of the first portion 11, and a front side 31F that conforms to the wearer's prescription.

[0082] The tape 32 is designed to be wrapped around the entire periphery 11E, 31E of the molded shell 31 and first portion 11 such that the first portion 11 and the molded shell 31 are maintained at a non-null distance from each other (the distance being determined as a function of the formulation).

[0083] For this purpose, the molded shell 31 and the first part 11 are fixed on respective spindles (not shown) in front of each other and at a convenient distance from each other. A first extremity of the tape 32 is then applied to both peripheral edges 11E, 31E. The two elements (molded shell 31 and first part 11) are then driven in rotation about their main axis A1 so that the tape 32 is wound around these peripheral edges 11E, 31E.

[0084] The rotation is stopped before the two elements have completed one revolution, so that at this step only the main portion of the tape 32 is attached to the elements, as shown in Figure 7. The remainder is kept away from the elements to keep the opening 33 open.

[0085] The mold cavity defined between the two elements is then filled with monomer.

[0086] It can be seen that the resin material (monomer) for forming the second portion 12 is substantially the same as that used to mold the first portion 11 (and thus different from that used to manufacture the microlenses).

[0087] The remaining portion of the tape 32 is then pressed against the periphery 11E, 31E of the two elements to close the opening 33. At this step, the mold assembly 30 can be placed in a polymerization apparatus so that the mold cavity is sealed to produce the eyeglass lens 10.

[0088] The fifth and final step is then to remove the eyeglass lens 10 from the molding assembly 30.

[0089] To this end, once the lens has been polymerized, the molded spectacle lens 10 is formed by peeling off the tape 32 to separate the molded shell 31 from the remainder.

[0090] In this step, the microlenses 20 are completely embedded in the base 13, so that the spectacle lens 10 has smooth front and back sides without any irregularities.

[0091] The invention is in no way limited to the embodiments described and shown.

[0092] In particular, the microlens may be affixed to a backside 12 of a base 13 and a front side 11 molded to the backside 12 .

Claims

1. 1. A method for manufacturing a spectacle lens (10) comprising a base (13) and a plurality of solid optical elements (20) having refractive properties different from those of the base (13) and embedded in the base (13), comprising the steps of: - providing said solid optical element (20) and a first part (11) of said base (13); - placing said solid optical element (20) inside (11R) of said first portion (11) of said base (13); - manufacturing a second part (12) of said base (13) on said inner side (11R) of said first part (11) of said base (13) and on said solid optical element (20) to obtain said spectacle lens (10).

2. The method of claim 1 , wherein at least two of the solid optical elements (20) exhibit different refractive properties.

3. 3. The method of claim 1, wherein at least one of the solid optical elements (20) exhibits a non-null cylindrical power.

4. The method according to any one of claims 1 to 3, wherein the positioning step comprises bonding the solid optical element (20) to an inner side (11R) of the first portion (11) of the base (13).

5. The method according to any one of the preceding claims, further comprising applying an adhesive material to an inner side (11R) of the first portion (11) of the base (13) or to a front surface of each solid optical element (20) prior to said positioning step.

6. The method of claim 5 , wherein the adhesive material is polymerizable.

7. The method of claim 6 , wherein the adhesive material is polymerized prior to the manufacturing step.

8. 8. The method according to claim 7, wherein the solid optical elements (20) are deposited on the inner side (11R) one by one in groups of at least one solid optical element (20), and the adhesive material located between the last deposited group and the inner side (11R) is polymerized before another group is deposited on the inner side (11R).

9. A method according to any one of claims 4 to 8, wherein said adhesive material is disposed on said inner side (11R) along an annular contour.

10. The method according to any one of the preceding claims, wherein the first portion (11) is a front portion of the spectacle lens (10) and the inner side (11R) is a rear side of the front portion.

11. The method according to any one of the preceding claims, wherein the manufacturing step comprises molding the second portion (12) of the base (13) by means of a molding assembly (30).

12. 12. The method according to claim 11, wherein the forming assembly (30) comprises a forming shell (31) having the same diameter as the diameter of the first portion (11), and a tape (32) wrapped around the periphery (11E, 31E) of the forming shell (31) and the first portion (11) to maintain the first portion (11) and the forming shell (31) at a non-null distance from each other, and an inner side (11R) of the first portion (11) is directed towards the forming shell (31).

13. 13. The method according to claim 11 or 12, comprising the step of removing the spectacle lens (10) from the molding assembly (30) after said manufacturing step.

14. The method according to any one of the preceding claims, wherein said first portion (11) is shaped prior to said providing step.

15. The method according to any one of the preceding claims, wherein the solid optical element (20) is molded prior to the providing step.

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