Method for coating lenses with lenticules having improved control of power shift

Abstract

The present disclosure relates to a method for coating an optical lens, the main surface of which is at least partially covered with lenslets. The optical lens is immersed in a coating fluid, taken out to reach an initial position, the initial position being defined such that said main surface faces a first horizontal direction, and the coating fluid coating said optical lens is dried. After taking out the optical lens and before or simultaneously with drying the coating fluid, the optical lens is tilted to a final position, the final position being defined such that said main surface faces upward a final direction, the final direction having an angle comprised between 80° and 100° with respect to the first direction, the first and final directions defining a vertical plane. Alternatively or in combination, while taking out said optical lens, part of the coating fluid is removed from the optical lens by sliding said optical lens along a mechanical blade.

Description

Technical Field

[0001] This disclosure pertains to the field of ophthalmic optics. Generally, this disclosure relates to the coating of optical lenses.

[0002] Specifically, a method for coating an optical lens, along with a corresponding computer program, storage medium, and processing circuitry, is disclosed, wherein the main surface of the optical lens is at least partially covered with a small lens. Background Technology

[0003] In the ophthalmology industry, people have known for decades about surface treatment of optical lenses.

[0004] For example, some lens prescriptions require sun protection to safeguard the eyes. Tinting is the most common method for converting clear lenses into sun-protective lenses. Depending on the material forming the lens, it's not always possible to tint the entire optical lens. For instance, polycarbonate does not readily absorb dye molecules. Therefore, polycarbonate-based optical lenses rely on a tintable hard coating that readily absorbs dye molecules to achieve tintability.

[0005] The most common methods for applying hard coatings to optical lenses are dip coating and spin coating.

[0006] A known problem with dip coating is controlling the thickness of the resulting hard coating.

[0007] For many applications, it has been found desirable to incorporate multiple microlenses (such as microlenses) on a base lens substrate to provide localized variations in the power of the optical article. For example, a lens is known from US 2017 / 0131567 that includes multiple microlenses formed on the lens surface, the localized variations in power provided by the microlenses capable of suppressing or slowing the progression of myopia.

[0008] In this respect, the substrate coated on at least one surface, including a microlens, affects the resulting optical power at the microlens. This effect can be compensated for by pre-adjusting the optical power of the microlens during substrate manufacturing. However, such adjustment may only be suitable for compensating for the effect of a specific expected thickness of the hard coating.

[0009] Therefore, if we want to compensate for the effect of the hard coating on the optical power of the microlens by uniformly adjusting the optical power of the microlens, we need to further assume that the thickness of the hard coating is completely uniform across the entire optical lens.

[0010] Furthermore, if the thickness of the hard coating is uneven on a given spherical microlens, the hard coating will introduce asphericity, and the microlens will appear distorted to the wearer.

[0011] In this case, it is necessary to reduce the tolerance of the coating thickness. This allows for minimizing any deformation of the microlens caused by coating thickness inhomogeneities. As a result, the sphericity or asphericity of optical lenses including microlenses on at least one main surface can be better controlled. This can improve the production reliability and efficiency of all end products. Summary of the Invention

[0012] This invention is defined by the appended independent claims. Additional features and advantages of the concepts disclosed herein are set forth in the following description.

[0013] This disclosure aims to improve this situation. To this end, this disclosure describes a method for coating an optical lens, the main surface of which is at least partially covered with a small lens, the method comprising:

[0014] - Immerse the optical lens in the coating fluid.

[0015] - The optical lens is removed from the coating fluid to reach an initial position, defined such that the main surface faces a first horizontal direction, and

[0016] -Dry the coating fluid used to coat the optical lens.

[0017] The method includes tilting the optical lens to a final position after removing the optical lens and before or simultaneously with drying the coating fluid. The final position is defined such that the main surface faces upward toward a final direction, which has an angle between 80° and 100° relative to a first direction. The first direction and the final direction define a vertical plane.

[0018] In the initial position, i.e., vertical, the fluid tends to flow towards the lower edge of the optical lens under the influence of gravity. Considering that the microlens is a complex structure, the same effect applies to the size of the microlens, causing the amount of fluid to tend to be larger, thus resulting in excess thickness at the lower edge of the microlens.

[0019] By tilting the optical lens, the fluid tends to spread better on the main surface of the optical lens on which the microlenses are arranged. Specifically, considering a given microlens on the main surface of the optical lens, when the optical lens is in its final position, i.e., basically horizontal, the fluid tends to have a more uniform thickness on the surface of the microlens.

[0020] Therefore, by tilting the fluid-coated optical lens with a small lens to a final, substantially horizontal position, and then drying the coating fluid at this final position, an optical lens with a small lens is provided, the hard coating having a more uniform thickness than that known in the prior art.

[0021] In the example, tilting the optical lens to its final position includes:

[0022] - Tilt the optical lens from its initial position to an intermediate position, defined as such that the main surface faces upward toward a second direction within the vertical plane, the second direction having an angle between 105° and 125° relative to the first direction, then...

[0023] - Tilt the optical lens from the middle position to the final position.

[0024] Considering that in the initial position, the coating fluid flows in a given downward direction, and then in the intermediate position, the coating fluid is allowed to flow back in the opposite direction. This intermediate position is particularly significant for forcing the relatively viscous coating fluid to be uniformly distributed on the main surface of the optical lens, and more specifically on the surface of each particular microlens, before drying.

[0025] Due to this uniform distribution, the appearance of the small lens and the resulting optical function of the optical lens are uniformly affected by the presence of the hard coating. The effects of a hard coating with uniform thickness may be more easily compensated for compared to a hard coating with non-uniform thickness.

[0026] In the example, the optical lens is removed from the coating fluid at a constant removal rate.

[0027] In one example, the optical lens is removed from the coating fluid at a gradually decreasing removal rate.

[0028] The removal speed is an example of an adjustable parameter that affects coating uniformity. Choosing a specific constant removal speed or a specific deceleration of the removal speed is an option that depends on the physical properties of the coating fluid (particularly in terms of viscosity and surface tension) and its interaction with the substrate (in terms of physical adhesion).

[0029] In the example, the method includes waiting for a predetermined amount of time, up to 3 seconds, after removing the optical lens and before tilting the optical lens, to allow a portion of the coating fluid used to coat the optical lens to drip off.

[0030] By allowing some of the coating fluid to drip off, the total amount of coating fluid remaining on the optical lens is reduced, thereby thinning the hard coating after drying.

[0031] In the example, the tilting optical lens is based on smooth, continuous motion.

[0032] Smooth, continuous motion allows the coating fluid to gradually stop flowing toward the lower edge of the optical lens in its initial position, then retreat and spread evenly across the main surface covered with the small lens.

[0033] In the example, the coating fluid used to dry the optical lens includes controlling the temperature at the main surface of the optical lens.

[0034] Typically, a single temperature plateau or a series of elevated temperature plateaus can be selected to evaporate the solvent at a specific rate to dry the hard coating within a predetermined time.

[0035] In the example, the coating fluid for drying the optical lens includes controlling the gas flow rate at the main surface of the optical lens.

[0036] Establishing a gas flow allows for the evaporation of the solvent. Therefore, the gas is far from saturated, and solvent evaporation may continue until a dry, hard coating forms.

[0037] On the other hand, a method for coating an optical lens, wherein the main surface of the optical lens is at least partially covered with a small lens, the method comprising:

[0038] - Immerse the optical lens in the coating fluid.

[0039] - The optical lens is removed from the coating fluid to reach an initial position, defined such that the main surface faces a first horizontal direction, and

[0040] -Dry the coating fluid used to coat the optical lens.

[0041] The method includes removing a portion of the coating fluid from the optical lens by sliding it along a mechanical blade while removing the optical lens.

[0042] Mechanical blades allow the removal of excess coating fluid, which would otherwise accumulate at the bottom of the optical lens and cause localized over-thickness of the coating after drying.

[0043] In the example, the method includes tilting the optical lens to a final position after removing the optical lens and before or simultaneously with drying the coating fluid. The final position is defined such that the main surface faces upward toward a final direction, which has an angle between 80° and 100° relative to a first direction, the first direction and the final direction defining a vertical plane.

[0044] This actually corresponds to combining the two aspects proposed to provide a composite advantage in realizing an optical lens comprising a small lens on at least one of its main surfaces and covered with a hard coating whose thickness is particularly uniform across the entire surface and on the surface of each particular small lens.

[0045] Embodiments of the present invention further provide a computer program comprising one or more stored instruction sequences that are accessible by a processing unit and, when executed by the processing unit, cause the processing unit to perform at least a portion of the proposed method.

[0046] An embodiment of the present invention further provides a storage medium that stores one or more stored instruction sequences of the above-described computer program.

[0047] An embodiment of the present invention further provides a processing circuit comprising a processing unit connected to a memory and a communication interface with at least one or more motors, the processing circuit being configured to implement the above method by at least directing one or more motors to control the position and / or orientation of an optical lens, the main surface of the optical lens being at least partially covered by a small lens.

[0048] The above-described method, computer program, storage medium, and processing circuitry allow for the uniform coating of the main surface of an optical lens, the main surface of which is at least partially covered by a small lens. Attached Figure Description

[0049] To gain a more complete understanding of the descriptions and advantages provided herein, please refer now to the following brief description in conjunction with the accompanying drawings and detailed description, wherein the same reference numerals denote the same parts.

[0050] Figure 1 A single-step tilt of an optical lens according to an exemplary embodiment is shown.

[0051] Figure 2 A two-step tilt of an optical lens according to an exemplary embodiment is depicted.

[0052] Figure 3 The appearance of an optical lens with a coated layer is depicted, which has an uneven thickness due to the unfavorable flow of the coating during drying.

[0053] Figure 4 The appearance of an optical lens coated with a layer according to an exemplary embodiment is depicted, the thickness of which is greater than that of a conventional optical lens. Figure 3 The optical lenses have a more uniform thickness.

[0054] Figure 5 An exemplary processing circuit according to an exemplary embodiment is depicted.

[0055] Figure 6 A flowchart illustrating a computer-implemented method according to an exemplary embodiment is provided.

[0056] Figure 7A , Figure 7B and Figure 7C A side view, a front view, and a close-up front view of a straight mechanical blade according to an exemplary embodiment are depicted.

[0057] Figure 7D A close-up front view of another straight mechanical blade according to an exemplary embodiment is depicted.

[0058] Figure 8A , Figure 8B and Figure 8C A side view, a close-up side view, and a front view of a bending mechanical blade according to an exemplary embodiment are depicted. Detailed Implementation

[0059] This disclosure describes alternative methods for solving the same problem of controlling the thickness uniformity of a hard coating on an optical lens (preferably an ophthalmic lens) having a main surface at least partially covered by a small lens. These methods can, of course, be used in combination.

[0060] The end result is an optical lens whose hard coating has a uniform effect on the optical function or focal length shift of the microlens. This effect can be easily compensated upstream by uniformly shifting the optical function of the microlens during its manufacture.

[0061] The structural aspects of optical lenses will be described later. Optical lenses include small lenses that can be arranged on the main surface of the optical lens on the convex front side (also known as the object side) or the concave back side (also known as the eyeball side), or on both main surfaces.

[0062] Small lenses can form protrusions and / or depressions on the main surface on which they are arranged. The outline of the small lenses can be circular or polygonal, such as hexagonal.

[0063] More specifically, in the following text, a small lens is a discrete optical element that causes localized changes in the optical power of an optical device.

[0064] More specifically, the small lens can be a microlens. A microlens can be spherical, toric, or have an aspherical shape, and can be rotationally symmetric or non-rotationally symmetric. A microlens can have a single focal point, cylindrical power, or a non-focal point. In a preferred embodiment, the small lens or microlens can be used to prevent the progression of myopia or hyperopia. In this case, the base lens substrate includes a base lens that provides optical power for correcting myopia or hyperopia, and respectively, if the wearer is myopic, the small lens or microlens can provide optical power greater than that of the base lens, or if the wearer is hyperopic, the microlens can provide optical power less than that of the base lens.

[0065] Microlenses or pinholes can also be Fresnel structures, diffractive structures (such as microlenses defining each Fresnel structure), permanent technical protrusions, or phase-shifting elements. Microlenses can also be refractive optical elements such as microprisms and light-diffusing optical elements such as small protrusions or cavities, or any type of element that creates roughness on a substrate.

[0066] Microlenses or small lenses can also be π-Fresnel microlenses as described in US2021109379 A1, i.e., Fresnel microlenses whose phase function has a π phase jump at the nominal wavelength, as opposed to single-focus Fresnel lenses with multiple values ​​of 2π phase jumps. Such microlenses include structures with discontinuous shapes. In other words, the shape of this structure can be described by a height function, exhibiting discontinuities in distance from the reference plane of the principal surface of the optical lens to which the microlens belongs, or by a discontinuous derivative thereof.

[0067] The microlens of the present invention can have an external shape that can be inscribed within a circle with a diameter greater than or equal to 0.5 micrometers (μm) and less than or equal to 1.5 millimeters (mm).

[0068] The microlenses of the present invention have a maximum height, measured in a direction perpendicular to a main surface on which they are arranged, greater than or equal to 0.1 μm and less than or equal to 50 μm. The main surface can be defined as the surface including the center point of each microstructure, and can be a plane, a sphere, a cylindrical surface, or even a composite surface. When the microstructure is embedded in the lens, the main surface can be a virtual surface, or when the microstructure is not embedded, it can be close to or identical to the physical outer surface of the ophthalmic lens. The height of the microstructure can then be determined using a local axis perpendicular to this main surface, and the difference between the maximum positive deviation along this axis and the minimum negative deviation from the main surface can be calculated for each point of the microstructure.

[0069] Microlenses can have a periodic or pseudo-periodic layout, but they can also be randomly positioned. Exemplary layouts of microlenses can be grids with a constant grid step size, honeycomb layouts, multiple concentric rings, or continuous layouts, such as those with no space between microstructures.

[0070] These structures can provide light wavefront modification in terms of intensity, curvature, or optical deviation, wherein the intensity of the wavefront is configured such that the structure can be absorbent and can locally absorb wavefront intensity in the range of 0% to 100%, wherein the curvature is configured such that the structure can locally modify the wavefront curvature in the range of + / -20 diopters, and wherein the optical deviation is configured such that the structure can locally scatter light at an angle of + / -1° to + / -30°.

[0071] The distance between structures can range from 0 (continuous) to 3 times the distance between structures (separate microstructures).

[0072] Today, optical lenses can typically be equipped with a variety of additional functions using hard coatings. Hard coatings are generally superior to the soft coatings used previously, and are made of thin film stacks, such as those composed of silver, zinc sulfide, cryolite, etc. In fact, hard coatings are very robust; their edges are less prone to degradation when exposed to moisture than those of soft coatings, and through typical use, they exhibit significantly better wavelength transmission than soft coatings, which remains unchanged over time and with use.

[0073] To apply a hard coating to an optical lens, a dip-coating technique can be used. Dip-coating an optical lens first involves immersing it in a container filled with a liquid (e.g., varnish), which is a solution of the coating material in a volatile solvent. If the coating is applied only to one or a portion of the main surface, the rest of the optical lens can be covered, for example, with a film to be subsequently peeled off. After immersion, the optical lens is removed from the container and allowed to dry. Through the evaporation of the solvent, the coating material forms a hard layer covering the optical lens. This evaporation can be accelerated by using airflow and by controlling ambient pressure and temperature.

[0074] Crucially, it is essential to ensure that a specific amount of coating material is applied to the optical lens and that this amount is distributed to form a layer with a substantially uniform thickness. In particular, this layer should have a uniform thickness on the surface of any given microlens. To achieve this, various parameters are controllable at each stage.

[0075] For example, the composition of the coating fluid affects its physical properties, particularly viscosity and surface tension, both of which influence the degree to which the coating fluid is retained on complex surfaces before drying. Therefore, the composition of the coating fluid is an example of a controllable parameter in terms of the properties of the solvent and solute, as well as the concentration of the solute. In the context of this document, it is always assumed that the coating fluid has a composition suitable for coating optical lenses comprising small lenses on one or both main surfaces.

[0076] For example, the speed at which an optical lens is removed from the can and how that speed affects how the coating remains on the surface of the optical lens. Therefore, one example of a controllable parameter is whether the optical lens is removed from the can at a constant speed or, conversely, at a gradually decreasing speed that is more conducive to achieving uniformity in the thickness of the hard coating.

[0077] The problem that occurs when an optical lens is immersed in a fluid container and then completely removed from the container is that, due to gravity, the fluid coating the optical lens tends to flow downwards and accumulate at the lower edge. This is true across the entire size range of the optical lens, as well as at the smaller size of individual microlenses, thus forming a meniscus at the lower edge of each individual microlens.

[0078] After the fluid dries, the meniscus formed at the lower edge becomes locally excessively thick. In other words, the coating exhibits a thickness gradient and has a non-uniform effect on the optical power at the microlens.

[0079] To prevent or at least reduce such thickness variation, in one embodiment, it is proposed to tilt the removed fluid-coated optical lens before and / or simultaneously with drying the coating fluid.

[0080] Now for reference Figure 1 The figure shows an exemplary single-step tilt of this optical lens.

[0081] After the optical lens is completely removed from the fluid tank, it remains vertically in the initial position (1). The initial position (1) can be defined as such that the profile of each principal surface lies within its corresponding vertical plane. A possible alternative definition, for example, considering that the small lens is positioned on the front principal surface, is that in the initial position (1), the normal to the front principal surface at its geometric center faces the horizontal initial direction X0.

[0082] Mutually orthogonal standard basis vectors (X, Y, Z) can be defined, where X points to a first direction corresponding to the initial direction X0, Y points to a second horizontal direction, and Z points to a third vertical direction. In this case, when the optical lens is in the initial position (1), the contours of the main surface are all located in the corresponding parallel planes, which can be defined by the points and vectors Y and Z belonging to the contours.

[0083] From the initial position (1), the optical lens is tilted until it reaches the final position (3) where the optical lens is horizontally positioned. Figure 1 In the process, the tilt is completed in one step and the optical lens rotates from the initial position (1) to the final position (3) around the axis pointed to by the vector Y, with a rotation angle between 80° and 100°.

[0084] For example, consider a 90° tilt from the initial position (1) to the final position (3). In this case, at the final position (3), the profile of each master surface lies in the corresponding horizontal plane, which can be defined by points and vectors X and Y belonging to the profile. At the geometric center of the front master surface, the normal of the front master surface faces the final direction X. F The final direction is vertical, facing upwards, and corresponds to vector Z.

[0085] By tilting the optical lens at an angle of 80° to 100° and reaching the final position (3), the coating fluid layer on which the optical lens is coated becomes flat: the thickness of the coating fluid layer is more uniform across the entire main surface on which the small lenses are arranged. Any local excess thickness is also minimized.

[0086] Starting from the initial position (1), the optical lens can be tilted as described above immediately or after a predetermined time (e.g., set to 3 seconds or less) to allow excess coating fluid to drip back into the tank. This predetermined time is an example of a controllable parameter.

[0087] The tilting itself can be performed at a specific speed, which is another example of a controllable parameter. For example, rotational motion can be completed at a constant speed within a predetermined time period, ranging from 3 to 10 seconds.

[0088] Drying can be performed, for example, over approximately 15 to 20 minutes, by subjecting the optical lens to a predetermined temperature program at the final position (3), which may include one or more temperature plateaus. Throughout the process, the optical lens may be subjected to a gas flow. The temperature program, as well as the properties and flow rate of the gas, are other examples of controllable parameters that can be adjusted to form an optimized set of parameters for a particular coating fluid and / or to achieve a specific target thickness of the coating.

[0089] Now for reference Figure 2 The figure depicts the double-step tilt of this optical lens.

[0090] exist Figure 2 In the middle, the optical lens from and Figure 1 The same initial position (1) tilts to the same final position (3), but the transition between the two positions is not monotonous.

[0091] Instead, the optical lens first reaches the intermediate position (2) due to the rotation of the optical lens about the axis pointed to by the vector Y, which exceeds the target angular difference of 80° to 100° relative to the initial position (1) reached later at the final position (3). Only then will the optical lens tilt in the opposite direction to reach the final position (3).

[0092] Instead, at the middle position (2), the normal of the front master surface at the geometric center of the front master surface faces the middle direction X. i It forms an angle between 105° and 125° with the initial direction X0.

[0093] The lower edge of the optical lens in the initial position (1) becomes the upper edge in this intermediate position (2). This allows the coating fluid to flow in the opposite direction to that before tilting.

[0094] Therefore, by rotating the optical lens upward to the intermediate position (2), unlike simply rotating the optical lens to the final position (3), any local excess thickness of the coating is further reduced. Compared to the single-step tilt described above, the double-step tilt thus allows for a better smoothing of the coating when the coating fluid can only flow slowly due to its high viscosity.

[0095] Now for reference Figure 3 The figure is a picture of an optical lens coated with a spherical microlens (4), which has a circular profile and is arranged in concentric rings on its convex surface.

[0096] Figure 3 The optical lens was dipped vertically into a coating fluid tank for coating, then removed vertically and dried, remaining vertical and without tilting during the process.

[0097] Figure 3 Specifically depicting a portion of the convex surface of a horizontally placed, coated optical lens. Figure 3 The left side corresponds to the upper side of the optical lens during the drying process. Conversely, Figure 3 The right side corresponds to the lower side of the optical lens during the drying process.

[0098] It can be seen that each microlens includes the same deformed, crescent-shaped appearance, which is detrimental to its optical properties. In fact, after the optical lenses are removed and while the coating fluid is drying, a meniscus is systematically formed at the lower end of each microlens (4) due to the flow of the coating fluid. This curing of the meniscus results in localized excessive thickness of the hard coating covering the microlens, which appears crescent-shaped in region (5).

[0099] Now for reference Figure 4 The image shows another coated optical lens. This lens is similar to... Figure 3 The only difference in the lens described is that the optical lens has been removed from the tank filled with coating fluid to reach the initial position, then tilted at an angle of 80° to 100° relative to the initial position toward the final position, and finally dried while held in the final position.

[0100] from Figure 4 As can be seen, each small lens (4) has a roughly spherical appearance and no... Figure 3 The excessively thick crescent-shaped area observed in the image. Therefore, due to the tilt, the overall appearance of the microlens is preserved after coating the optical lens, i.e., it matches the actual shape of the microlens before coating. More importantly, the optical properties of the microlens are uniformly affected by the hard coating, both at the scale of individual microlenses and between microlenses, i.e., at the scale of the entire optical lens.

[0101] The above combination Figure 1 and Figure 2 Described and produced as Figure 4 The method for producing the optical lens shown can be performed manually by an operator, or semi-automatically, or even fully automatically. Semi-automatic operation is suitable for testing various controllable parameters at different values ​​and then checking the quality of the resulting coated optical lens (e.g., by capturing...). Figure 4The image shown is necessary to finally approve a set of optimized values ​​for controllable parameters. Full automation is critical for reliably enabling mass production of coated optical lenses having microlenses on at least one of their main surfaces and a coating of uniform thickness on the microlenses.

[0102] Typically, an optical lens can be held by a lens holder that can be translated and rotated by an operating motor (e.g., a stepper motor). In semi-automatic cases, the translational and rotational movements can be directly controlled by the operator, or in fully automated cases, they can be pre-programmed.

[0103] Now for reference Figure 5 and Figure 6 , Figure 5 An exemplary processing circuit is depicted. Figure 6 A general algorithm for a computer program is described, the computer program comprising one or more instructions that can be executed by such processing circuitry to perform a method for coating an optical lens, the main surface of which is at least partially covered by a small lens.

[0104] Figure 5 The processing circuit (100) shown includes a processing unit (101) operatively coupled to a non-transitory memory (102) capable of storing the aforementioned computer program and a communication interface (103) that allows operation at least the operation of a motor for translating and / or rotating a lens holder holding the optical lens. The communication interface (103) further allows the receiving of commands originating from interaction with a human-machine interface. The communication interface (103) further allows operation of a heat generator for controlling the temperature at the optical lens and / or a valve for controlling the gas flow rate at the optical lens. As described above, temperature and gas flow rate can be controllable parameters for optimizing the drying of the coated optical lens.

[0105] The processing unit operates one or more motors to translate the lens holder to immerse the held optical lens into (10) a tank filled with coating fluid.

[0106] The processing unit then operates one or more motors to translate the lens holder to remove the held optical lens (20) from the container. This translational motion can be defined by an initial velocity and acceleration, both of which are controllable or adjustable parameters.

[0107] Optionally, an adjustable waiting time of up to three seconds can allow excess coating fluid to drip back into the tank from the optical lens.

[0108] The processing unit then operates one or more motors to rotate the lens holder, thereby rotating the retrieved optical lens. The rotation can be, for example... Figure 1 The single-step rotation (31) shown is similar to, for example... Figure 2 Choose between the two-step rotations (32) shown. Rotation speed and acceleration are adjustable parameters.

[0109] Finally, the optical lens is dried (40) following an adjustable temperature program and at an adjustable gas flow rate, such as air or, when the coating is protected against oxidation, an inert gas (e.g., argon).

[0110] Therefore, the optical lens is covered with a dry hard coating, which has a uniform thickness on the microlens.

[0111] The process can then be repeated on the same optical lens with the same coating fluid, possibly using different adjustable parameter values, to form a double-layer hard coating.

[0112] The process can also be repeated on the same optical lens with different coating fluids, possibly using different adjustable parameter values, to form multilayer hard coatings with different compositions and providing different properties.

[0113] It is also proposed to use a mechanical blade, also known as a mechanical droplet destroyer, to homogenize the coating on the main surface of an optical lens, which includes a small lens.

[0114] For this purpose, the optical lens is maintained in such a way that there is a prolonged contact between the bottom of the lens and the mechanical blade. The lens, thus held in place, is dipped in a coating and then removed at a uniform or gradual removal speed.

[0115] When the lens is removed from the coating fluid, the coating film is "pulled out" by a mechanical blade due to surface tension (capillary force). As a result, the thickness of the coating and its effect on the apparent shape and optical power of the microlens are homogenized.

[0116] In other words, when such a mechanical blade is arranged to be in contact with an optical lens for an extended period of time, the coating thickness is homogenized because the mechanical blade passively removes excess coating fluid while the optical lens is actively removed from the tank filled with coating fluid.

[0117] like Figure 1 or Figure 2 The thickness of the coating can be further homogenized by actively rotating the optical lens, as described.

[0118] Now for reference Figure 7A , Figure 7B , Figure 7C , Figure 7D , Figure 8A , Figure 8B and Figure 8CThese figures depict different views of different types of mechanical blades (7) as the optical lens (6) is removed from a tank filled with a coating fluid, shown in contact with the optical lens (6), which includes a small lens on one of its main surfaces.

[0119] Specifically, Figure 7A , Figure 7B and Figure 7C Different views of a straight mechanical blade without chamfering are shown. Figure 7D A straight mechanical blade with a chamfer is shown. Figure 8A , Figure 8B and Figure 8C Different views of the curved portion of a curved or serrated mechanical blade are shown.

[0120] The mechanical blade can be made of metal or other materials that allow the coating fluid to flow. The blade width is small, for example, between 0.5 mm and 2 mm, to avoid creating lateral defects such as marks on the optical lens (6). Figure 7D As shown, the additional chamfer can further reduce the width of the blade (7) at the point of contact with the optical lens (6).

[0121] The blade can be straight, such as... Figure 7A , Figure 7B , Figure 7C and Figure 7D As depicted. Conversely, the blade can be as... Figure 8A , Figure 8B and Figure 8C The blade (7) is curved or serrated, especially for lenses with thick edges, to ensure better contact between the convex and concave sides of the lens (6).

Claims

1. A method for coating an optical lens, wherein the main surface of the optical lens is at least partially covered with microlenses, each microlens having an external shape capable of being inscribed within a circle with a diameter greater than or equal to 0.5 micrometers and less than or equal to 1.5 millimeters, and a maximum height measured in a direction perpendicular to the main surface, said maximum height being greater than or equal to 0.1 micrometers and less than or equal to 50 micrometers, the method comprising: - Immerse the optical lens in the coating fluid. - The optical lens is removed from the coating fluid to reach an initial position, defined such that the main surface faces a first horizontal direction, and -Dry the coating fluid used to coat the optical lens. The method includes tilting the optical lens to a final position after removing the optical lens and before or simultaneously with drying the coating fluid. The final position is defined such that the main surface faces upward toward a final direction, which has an angle between 80° and 100° relative to a first horizontal direction. The first horizontal direction and the final direction define a vertical plane.

2. The method according to claim 1, wherein, Tilting the optical lens to the final position includes: - Tilt the optical lens from the initial position to an intermediate position, the intermediate position being defined such that the main surface faces upward toward a second direction in the vertical plane, the second direction having an angle between 105° and 125° relative to the first horizontal direction, then - Tilt the optical lens from the intermediate position to the final position.

3. The method according to claim 1, wherein, The optical lens is removed from the coating fluid at a constant removal speed.

4. The method according to claim 1, wherein, The optical lens is removed from the coating fluid at a gradually decreasing removal speed.

5. The method according to claim 1, wherein, The method includes waiting for a predetermined amount of time, up to 3 seconds, after removing the optical lens and before tilting the optical lens to allow a portion of the coating fluid used to coat the optical lens to drip off.

6. The method according to claim 1, wherein, The tilting of the optical lens is achieved through smooth, continuous motion.

7. The method according to claim 1, wherein, The process of drying the coating fluid used to coat the optical lens includes controlling the temperature at the main surface of the optical lens.

8. The method according to claim 1, wherein, The coating fluid used to dry the optical lens includes controlling the gas flow rate at the main surface of the optical lens.

9. A non-transitory computer-readable storage medium having a program recorded thereon, which, when executed by a processor, is used to implement the method according to claim 1.

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