A method for coating lenses with lenslets, which improves the control of refractive power shift.

Abstract

The present disclosure relates to a method for coating an optical lens having a major surface at least partially covered with lenslets, the optical lens being immersed in a coating fluid and withdrawn to reach an initial position defined with the major surface facing towards a horizontal first direction, the coating fluid coating the optical lens being dried. After withdrawing the optical lens and before or during drying of the coating fluid, the optical lens is tilted to a final position defined with the major surface facing upwards towards a final direction having an angle of 80°-100° with respect to the first direction, the first direction and the final direction defining a vertical plane. Alternatively or in combination, during withdrawal of the optical lens, a portion of the coating fluid is removed from the optical lens by sliding the optical lens along a mechanical blade.

Description

[Technical Field]

[0001] This disclosure belongs to the field of ophthalmic optics. This disclosure generally relates to coatings for optical lenses.

[0002] Specifically, a method for coating an optical lens having a main surface at least partially covered with a lenslet, as well as a corresponding computer program, storage medium, and processing circuit are disclosed. [Background technology]

[0003] In the ophthalmology industry, surface treatment of optical lenses has been known for decades.

[0004] For example, some lens formulations require light-blocking functionality for eye protection. Tinting is the most common method of converting clear lenses into light-blocking lenses. Depending on the material forming the lens, it is not always possible to dye optical lenses in large quantities. For example, polycarbonate does not readily absorb dye molecules. Therefore, polycarbonate-based optical lenses rely on a colorable hard coating that readily absorbs dye molecules for coloring.

[0005] The most common methods for coating optical lenses with hard coatings are immersion coating and spin coating.

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

[0007] In some applications, it has been found desirable to provide localized changes in the refractive power of an optical article by providing multiple lenslets, such as microlenses, on a base lens substrate. For example, a lens comprising multiple microlenses formed on the surface of the lens is known from U.S. Patent Application Publication No. 2017 / 0131567, which can suppress or delay the progression of myopia by providing localized changes in refractive power.

[0008] In this regard, coating a substrate with a lenslet on at least one of its surfaces affects the resulting refractive power in the lenslet. This effect can be compensated for by pre-adjusting the refractive power of the lenslet when manufacturing the substrate. However, such adjustments can only be calculated to compensate for the effect of a specific expected thickness of the hard coating.

[0009] As a result, if the effect of the hard coating on the refractive power of the lenslet is to be compensated for by uniformly adjusting the refractive power of the lenslet, it is further necessary to assume that the thickness of the hard coating is perfectly uniform throughout the optical lens.

[0010] Furthermore, if the thickness of the hard coating is not uniform across a given spherical lenslet, the hard coating introduces asphericity, causing such a lenslet to appear distorted to the wearer.

[0011] In this regard, it is necessary to tighten the tolerances for the thickness of the coating layer. This will allow for minimizing any deformation of the lenslet resulting from non-uniformity of the coating layer thickness. As a result, the spherical or aspherical properties of an optical lens having a lenslet on at least one of its main surfaces can be better controlled. This can improve the reliability and efficiency of production of all final products. [Overview of the project] [Means for solving the problem]

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

[0013] This disclosure aims to improve the situation. For this purpose, this disclosure describes a method for coating an optical lens having a principal surface at least partially covered with a lenslet, the method being: - Immersing the optical lens in a coating fluid, - To pull the optical lens out of the coating fluid and bring it to an initial position where its principal surface faces a horizontal first direction, - Includes drying the coating fluid that coats the optical lens, This method includes, after the optical lens has been pulled out and before or during the drying of the coating fluid, tilting the optical lens to a final position such that its main surface faces upward toward a final direction having an angle of 80° to 100° with respect to a first direction, wherein the first direction and the final direction define a vertical plane.

[0014] In its initial position, i.e., vertical, the fluid tends to flow towards the lower edge (bottom end) of the optical lens due to the effect of gravity. If we consider the lenslet as a complex structure, the same effect applies at the lenslet's scale, resulting in a greater volume of fluid and therefore a tendency for excess thickness at the lower edge of the lenslet.

[0015] By tilting the optical lens, the fluid tends to spread more effectively across the entire principal surface of the optical lens on which the lenslet is positioned. In particular, given a given lenslet on the principal surface of the optical lens, if the optical lens is in a substantially horizontal final position, the fluid tends to have a more uniform thickness across the surface of the lenslet.

[0016] Thus, an optical lens having lenticels, coated with a fluid, is tilted to a substantially horizontal final position, and then the coating fluid is dried while in such a final position, resulting in an optical lens having lenticels, the hard coating of which has a more uniform thickness than is known in the prior art.

[0017] In one embodiment, tilting the optical lens to the final position includes the following: tilting the optical lens from an initial position to an intermediate position defined such that the main surface faces upward in a second direction within a vertical plane, the second direction having an angle of 105° to 125° with respect to the first direction, and then tilting the optical lens from the intermediate position to the final position.

[0018] Considering that at the initial position the coating fluid flows in a given downward direction, at the intermediate position it is possible to reverse the flow of the coating fluid in the opposite direction. Such an intermediate position is particularly interesting for evenly spreading a relatively viscous coating fluid over the entire main surface of the optical lens, and more specifically over the entire surface of each particular lenticel, before drying.

[0019] As a result of such even spreading, the appearance of the lenticels and the resulting optical function of the optical lens are uniformly affected by the presence of the hard coating. The effect of a hard coating having a uniform thickness can be compensated more easily than the effect of a hard coating having a non-uniform thickness.

[0020] In one embodiment, pulling the optical lens out of the coating fluid is performed at a constant pulling speed.

[0021] In one embodiment, pulling the optical lens out of the coating fluid is performed at a pulling speed that gradually decreases.

[0022] The withdrawal speed is an example of an adjustable parameter that affects the uniformity of the coating layer. Selecting a specific constant withdrawal speed or a specific deceleration of the withdrawal speed is a choice that depends on the physical properties of the coating fluid, particularly in terms of viscosity and surface tension, and the physical properties of its interaction in terms of physical adhesion to the substrate.

[0023] In one embodiment, the method includes waiting for a predetermined time equal to at most 3 seconds after withdrawing the optical lens and before tilting it, to allow a portion of the coating fluid coating the optical lens to drip off.

[0024] By allowing a portion of the coating fluid to drip off, the total amount of the coating fluid remaining on the optical lens is reduced, resulting in a thinner hard coating layer after drying.

[0025] In one embodiment, tilting the optical lens is performed according to a smooth continuous movement.

[0026] The smooth continuous movement makes it possible to gradually stop the flow of the coating fluid towards a portion of the optical lens located at the lower edge in the initial position, then to be able to retreat, and to be able to spread uniformly over the main surface covered by the lenslets.

[0027] In one embodiment, drying the coating fluid coating the optical lens includes controlling the temperature on the main surface of the optical lens.

[0028] Typically, a single temperature plateau or a series of increasing temperature plateaus may be selected to evaporate the solvent at a specific rate to dry the hard coating layer in a predetermined time.

[0029] <​​

[0030] Establishing a gas flow allows for the exhaust of evaporated solvent. Therefore, the gas remains far from saturation, and solvent evaporation can continue until a dry hard coating is formed.

[0031] In another embodiment, a method is proposed for coating an optical lens having a principal surface at least partially covered with a lenslet, and this method is - Immersing the optical lens in a coating fluid, - To pull the optical lens out of the coating fluid and bring it to an initial position where its principal surface faces a horizontal first direction, - Includes drying the coating fluid that coats the optical lens, This method includes removing a portion of the coating fluid from the optical lens by sliding the optical lens along a mechanical blade while the optical lens is being extended.

[0032] The mechanical blade allows for the removal of excess coating fluid, which would otherwise accumulate at the bottom of the optical lens, causing localized excess thickness of the coating layer after drying.

[0033] In one embodiment, the method includes, after the optical lens has been pulled out and before or during the drying of the coating fluid, tilting the optical lens to a final position such that its main surface faces upward toward a final direction having an angle of 80° to 100° with respect to a first direction, wherein the first direction and the final direction define a vertical plane.

[0034] This corresponds to actually combining both proposed embodiments and thereby providing a combined advantage in realizing an optical lens having a lenslet on at least one of its main surfaces and covered with a hard coating, wherein the thickness of the hard coating is particularly uniform across the entire surface of the optical lens and across the surface of each particular lenslet.

[0035] Embodiments of the present invention further provide a computer program which includes one or more stored instruction sequences that are accessible to a processing unit and cause the processing unit to perform at least a portion of the proposed method when executed by the processing unit.

[0036] Embodiments of the present invention further provide a storage medium for storing one or more stored instruction sequences of the above-described computer program.

[0037] Embodiments of the present invention further provide a processing circuit comprising a processing unit connected to a memory and connected to a communication interface with at least one motor, the processing circuit configured to implement the above method by commanding at least one motor to control the position and / or orientation of an optical lens having a main surface at least partially covered by a lenslet.

[0038] The above-described method, computer program, storage medium, and processing circuit make it possible to make the coating layer coating the main surface of the optical lens uniform, so that the aforementioned main surface is at least partially covered with lenslet.

[0039] To better understand the descriptions and advantages provided herein, please refer here to the following brief descriptions in relation to the attached drawings and detailed descriptions, where similar reference numbers represent similar parts. [Brief explanation of the drawing]

[0040] [Figure 1] Figure 1 shows an exemplary embodiment of tilting an optical lens in a single step. [Figure 2] Figure 2 shows an exemplary embodiment of tilting an optical lens in two steps. [Figure 3]Figure 3 shows the appearance of an optical lens coated with a layer of uneven thickness resulting from unwanted flow of the coating during drying. [Figure 4] Figure 4 shows the appearance of an optical lens coated with a layer having a more uniform thickness than the optical lens in Figure 3, according to an exemplary embodiment. [Figure 5] Figure 5 shows an exemplary processing circuit according to an exemplary embodiment. [Figure 6] Figure 6 shows a flowchart of a computer-based method according to an exemplary embodiment. [Figures 7A-7D] Figures 7A–7C show a side view, front view, and enlarged front view of a straight mechanical blade according to an exemplary embodiment, respectively. Figure 7D shows an enlarged front view of another straight mechanical blade according to an exemplary embodiment. [Figures 8A-8C] Figures 8A-8C show a side view, an enlarged side view, and a front view, respectively, of a curved mechanical blade according to an exemplary embodiment. [Modes for carrying out the invention]

[0041] This disclosure describes alternative methods for addressing the same problem of controlling the uniformity of the hard coating thickness of optical lenses, preferably ophthalmic lenses, having a principal surface at least partially covered with a lenslet. These methods may, of course, be combined.

[0042] The final result is an optical lens in which the hard coating has a uniform effect or refractive power shift on the optical function of the lenslet. Such an effect can be easily compensated upstream by appropriately and uniformly offsetting the optical function of the lenslet during its manufacture.

[0043] The structural aspects of the optical lens will be described below. The optical lens includes a lenslet which may be positioned on the convex front side (also called the object side) or the concave rear side (also called the eyeball side) of the main surface of the optical lens, or on both sides of the main surface.

[0044] Lenslets may form bumps and / or recesses on the main surface in which they are positioned. The contour of a lenslet may be circular or polygonal, such as hexagonal.

[0045] More specifically, in the following definition, a lenslet is a discrete optical element that induces a local change in the refractive power of an optical device.

[0046] More specifically, the lenslet may be a microlens. The microlens may be spherical, toric, or aspherical in shape, and may or may not be rotationally symmetric. The microlens may have a single focal point, cylindrical power, or nonfocal power. In a preferred embodiment, the lenslet or microlens can be used to prevent the progression of myopia or hyperopia. In this case, the base lens substrate comprises a base lens that provides refractive power to correct myopia or hyperopia, and the lenslet or microlens may each provide a refractive power greater than that of the base lens if the wearer has myopia, or a refractive power less than that of the base lens if the wearer has hyperopia.

[0047] Lenslets or microlenses may also be Fresnel structures, diffractive structures such as microlenses each defining a Fresnel structure, permanent technical bumps, or phase-shift elements. They may be refractive optical elements such as microprisms, and light-dispersive optical elements such as small protrusions or cavities, or any type of element that creates irregularities on a substrate.

[0048] A lenslet or microlens may be a π-Fresnel lenslet, as described in U.S. Patent Application Publication No. 2021109379A1, that is, a Fresnel lenslet whose phase function has a π phase jump at nominal wavelength. This is in contrast to a single-focal-length Fresnel lens, whose phase jump is a multiple of 2π. Such a lenslet includes a structure having a discontinuous shape. In other words, the shape of such a structure can be described by the elevation function in terms of the distance from the base level of the principal surface of the optical lens to which the lenslet belongs, and that function exhibits a discontinuity, or its derivative exhibits a discontinuity.

[0049] The lenslet of the present invention may have a contour shape that can be inscribed in a circle having a diameter of 0.5 micrometers (μm) or more and 1.5 millimeters (mm) or less.

[0050] The lenslets of the present invention have a maximum height of 0.1 μm or more and 50 μm or less when measured in a direction perpendicular to the principal surface on which they are positioned. The principal surface can be defined as a surface, and can be a plane, a sphere, a cylinder, or a more complex surface, and includes the central position of all microstructures. This principal surface can be a virtual surface when microstructures are embedded in the lens, or it can be close to or identical to the physical outer surface of the ophthalmic lens when microstructures are not embedded. In this case, the height of the microstructures can be determined by using a local perpendicular axis to this principal surface and calculating, for each point of the microstructure, the difference between the maximum positive deviation and the minimum negative deviation along this axis relative to the principal surface.

[0051] Lenslets may have a periodic or pseudo-periodic layout, or they may have random positions. Exemplary layouts of lenslets may be grids with a set grid step, honeycomb layouts, multiple concentric rings, for example, adjacent with no space between microstructures.

[0052] These structures can provide optical wavefront modification in terms of intensity, curvature, or optical deviation, where the wavefront intensity is configured such that the structure can absorb and locally absorb wavefront intensity in the range of 0% to 100%, the curvature is configured such that the structure can locally modify wavefront curvature in the range of ±20 diopters, and the optical deviation is configured such that the structure can locally scatter light at angles in the range of ±1° to ±30°.

[0053] The distance between structures can range from 0 times (adjacent) to 3 times the length of the structure (separate microstructure).

[0054] Today, optical lenses can be given various types of additional functions, usually through hard coatings. Hard coatings, which are made of layers of films composed of materials such as silver, zinc sulfide, and cryolite, are generally superior to the previously used soft coatings. In fact, hard coatings are robust, their edges are less susceptible to degradation than soft coatings when exposed to moisture and during normal use, and their wavelength transmittance is significantly better than that of soft coatings and remains constant over time and throughout use.

[0055] Immersion coating techniques may be used to apply a hard coating to an optical lens. Immersion coating of an optical lens involves first immersing the optical lens in a tank filled with a fluid. Such fluids include, for example, varnish and a solution of the coating material in a volatile solvent. If the coating is applied to only one of the main surfaces, or to only a portion of such surfaces, the rest of the optical lens can be covered with a film that will be peeled off later. After immersion, the optical lens is removed from the tank and dried. Due to the evaporation of the solvent, the coating material forms a hard layer covering the optical lens. Such evaporation can be accelerated by using a gas flow and by controlling the ambient pressure and ambient temperature.

[0056] It is essential to ensure that a specific amount of coating material is applied to the optical lens and that this amount of coating material is spread to form a layer with a generally uniform thickness. In particular, the layer should have a uniform thickness on the surface of any given lenslet. To this end, various parameters can be controlled at every stage.

[0057] For example, the composition of a coating fluid affects its physical properties, particularly its viscosity and surface tension. Both of these affect how well the coating fluid is retained by the complex surface before drying. Therefore, the composition of a coating fluid is an example of a controllable parameter, in terms of the properties of the solvent and solute, and in terms of the concentration of the solute. In connection with this specification, it is always assumed that the coating fluid has a composition suitable for coating an optical lens having a lenslet on one or both of its main surfaces.

[0058] For example, the speed at which the optical lens is drawn from the tank, and its variation, affects how the coating is retained on the surface of the optical lens. Therefore, an example of a controllable parameter is whether the optical lens is drawn from the tank at a constant speed, or, more preferably, at a gradually decreasing speed to achieve uniformity in the hard coating thickness.

[0059] The problem that arises when an optical lens is immersed in a fluid tank and then completely withdrawn from the tank is that, due to gravity, the fluid coating the optical lens tends to flow downward and accumulate at the lower edge. This is true at the overall scale of the optical lens, but also at the smaller scale of a single lenslet, and therefore a meniscus forms at the lower edge of every lenslet.

[0060] The formation of a meniscus at the lower edge signifies localized excess thickness after the fluid has dried. In other words, the coating layer exhibits a thickness gradient, resulting in an uneven effect on the refractive power of the lenslet.

[0061] To prevent, or at least reduce, such thickness variations, in one embodiment, it is proposed to tilt the drawn-out, fluid-coated optical lens before and / or during the drying of the coating fluid.

[0062] Referring to Figure 1, an example of tilting such an optical lens in a single step is shown.

[0063] When the optical lens is fully withdrawn from the fluid tank, it is held vertically in its initial position (1). The assumed definition of the initial position (1) is that, at that position, the contours of each principal surface lie in the corresponding vertical plane. An assumed alternative definition, considering, for example, that the lenslet is positioned on the front principal surface, is that, at the initial position (1), the normal to the front principal surface at its geometric center points in the horizontal initial direction X0.

[0064] A standard basis vector (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 such a case, when the optical lens is in its initial position (1), the contours of the principal surfaces each lie in the corresponding parallel planes defined by the points belonging to their contours and by the vectors Y and Z.

[0065] The optical lens is tilted from its initial position (1) until it reaches its final position (3) where it is horizontal. In Figure 1, the tilting is performed in a single step and is a rotation of the optical lens from the initial position (1) to the final position (3), with the rotation being at an angle of 80° to 100° around the axis pointed to by vector Y.

[0066] This rotation can be thought of as, for example, a 90° tilt from the initial position (1) to the final position (3). In such a case, at the final position (3), the contour of each principal surface lies in the corresponding horizontal plane, which can be defined by the points belonging to that contour and by vectors X and Y. The normal to the front principal surface at the geometric center of the front principal surface is in the final direction X. F It is oriented in a certain direction, which is perpendicular, pointing upwards, and corresponds to vector Z.

[0067] By tilting the optical lens at an angle of 80° to 100° to reach its final position (3), the layer of coating fluid coating the optical lens becomes flatter, and its thickness becomes more uniform across the entire main surface where the lenslet is positioned. Any localized excess thickness is minimized.

[0068] The optical lens can be tilted as described above, either immediately from its initial position (1) or after a predetermined time, for example, set to 3 seconds or less, allowing excess coating fluid to drip back into the tank. Such a predetermined time is an example of a controllable parameter.

[0069] The tilting itself may be performed at a specific speed, and such tilting speed is another example of a controllable parameter. For example, rotational movement may be performed at a constant speed within a predetermined time frame of 3 to 10 seconds.

[0070] Drying may be carried out for approximately 15-20 minutes by applying a predetermined temperature program to the optical lens, which may include one or more temperature flats, while it is in the final position (3). Throughout this process, the optical lens may be exposed to a gas flow. The temperature program, as well as the properties and flow rate of the gas, are further examples of controllable parameters that can be adjusted to form an optimized parameter set for a particular coating fluid and / or to achieve a specific target thickness of the coating layer.

[0071] Referring to Figure 2, it can be seen that such an optical lens can be tilted in two steps.

[0072] In Figure 2, the optical lens is tilted from the same initial position (1) to the same final position (3) as in Figure 1, but the transition between the two positions is not monotonous.

[0073] Rather, the optical lens first reaches an intermediate position (2) as a result of rotation around the axis pointed to by vector Y. This rotation exceeds the target angle difference of 80° to 100° between the initial position (1) and the final position (3), which it subsequently reaches. Only then is the optical lens tilted in the opposite direction to reach the final position (3).

[0074] Instead, at the intermediate position (2), the normal to the front principal plane at the geometric center of the front principal plane is in the intermediate direction X. i It faces in that direction, forming an angle of 105° to 125° with respect to the initial direction X0.

[0075] The lower edge of the optical lens in the initial position (1) becomes the upper edge when it is in such an intermediate position (2). This allows the coating fluid to flow in the opposite direction to before tilting.

[0076] Therefore, rotating the optical lens to the intermediate position (2) further recedes any localized excess thickness of the coating, in contrast to rotating the optical lens only to the final position (3). Thus, if the coating fluid can only flow slowly due to its high viscosity, tilting in two steps allows for relatively better planarization of the coating layer compared to tilting in a single step as described above.

[0077] Referring now to Figure 3, this is a photograph of a coated optical lens having spherical lenslets (4) with a circular contour, where the lenslets are arranged adjacently on a convex surface in the shape of concentric rings.

[0078] The optical lens in Figure 3 is immersed vertically in a coating fluid tank for immersion coating, then pulled out vertically and dried while remaining vertical; it is not tilted during this process.

[0079] Figure 3, in particular, depicts a portion of the convex surface of a coated optical lens placed horizontally. The left side of Figure 3 corresponds to the upper side of the optical lens during the drying process. Conversely, the right side of Figure 3 corresponds to the lower side of the optical lens during the drying process.

[0080] It can be seen that each lenslet has a similarly deformed crescent shape, which is detrimental to its optical properties. In fact, during the drying of the coating fluid after the optical lenses were removed, a meniscus was systematically formed at the lower end of each lenslet (4) due to the flow of the coating fluid. The solidification of such a meniscus resulted in a crescent-shaped localized excess thickness of the hard coating coating the lenslet in region (5).

[0081] Referring now to Figure 4, this is a photograph of another coated optical lens. Such a lens differs from the one shown in Figure 3 in that the optical lens is drawn from a tank filled with coating fluid to an initial position, then tilted toward a final position at an angle of 80° to 100° relative to the initial position, and finally dried while held in the final position.

[0082] Figure 4 shows that each lenslet (4) has a roughly spherical appearance, and there is no crescent-shaped region of excessive thickness as seen in Figure 3. Therefore, due to the tilt, the general appearance of the lenslets is retained after coating the optical lenses, i.e., it matches the actual shape of the lenslets before coating. More importantly, the optical properties of the lenslets are uniformly affected by the hard coating, both on a scale of individual lenslets and on a scale of lenslets to lenslets, i.e., on a scale of the entire optical lens.

[0083] The method described above in relation to Figures 1 and 2, and depicted in Figure 4, for producing an optical lens may be performed manually by an operator, semi-automated, or even fully automated. Semi-automation is necessary to test different values ​​of various controllable parameters, then check the quality of the resulting coated optical lens by, for example, capturing photographs as shown in Figure 4, and finally approve an optimized set of controllable parameters. Full automation is key to ensuring mass production of coated optical lenses having a lenslet on at least one of its main surfaces and a coating layer of uniform thickness across multiple lenslets.

[0084] Typically, the optical lens may be held by a lens holder, which can be translated and rotated by operating a motor, such as a stepper motor. The translational and rotational movements may be controlled by an operator in the case of semi-automation, or pre-programmed in the case of full automation.

[0085] Referring here to Figure 5, an exemplary processing circuit is shown, and referring to Figure 6, a general algorithm for a computer program containing one or more instructions is shown. The instructions may be executed by such a processing circuit, and in this way, a method for coating an optical lens having a principal surface at least partially covered with a lenslet may be implemented.

[0086] The processing circuit (100) shown in Figure 5 comprises a processing unit (101), which is operably coupled to a non-temporary memory (102) capable of storing the above-mentioned computer program, and is operably coupled to a communication interface (103) that at least enables the operation of a motor that translates and / or rotates a lens holder that holds an optical lens. The communication interface (103) may further enable the reception of commands arising from interaction with a human-computer interface. The communication interface (103) may further enable the operation of a heat generator for controlling the temperature in the optical lens, and / or a valve for controlling the gas flow rate in the optical lens. As previously mentioned, temperature and gas flow rate may be controllable parameters for the purpose of optimizing the drying of the coated optical lens.

[0087] The processing unit operates one or more motors to translate the lens holder so that the held optical lens is immersed in a tank filled with a coating fluid (10).

[0088] The processing unit then operates one or more motors to translate the lens holder so as to pull the held optical lens out of the tank (20). Such translational movement can be defined by an initial velocity and acceleration, both of which are controllable or adjustable parameters.

[0089] Optionally, an adjustable waiting time of up to 3 seconds allows excess coating fluid to drip back into the tank from the optical lens.

[0090] Next, the processing unit activates one or more motors to rotate the lens holder so as to rotate the pulled-out optical lens. The rotation may be selected between a single-step rotation (31), for example, as shown in Figure 1, and a two-step rotation (32), for example, as shown in Figure 2. The rotation speed and acceleration are adjustable parameters.

[0091] Finally, after the adjustable temperature program, the optical lenses are dried under an adjustable flow rate of a gas, which may be, for example, air, or an inert gas such as argon if the coating should be protected from oxidation (40).

[0092] As a result, the optical lens is covered with a dry hard coating layer having a uniform thickness across the lenslet.

[0093] This process may then be repeated on the same optical lens, using the same coating fluid, and possibly with different adjustable parameter values, thereby forming a two-layer hard coating.

[0094] This process may also be repeated on the same optical lens using different coating fluids and possibly different adjustable parameters, thereby forming a multilayer hard coating, where these layers have different compositions and provide different properties.

[0095] It has been further proposed to use a mechanical blade, also called a mechanical drop-breaking device, to make the coating film on the main surface of an optical lens uniform, such a main surface having a lenslet.

[0096] To achieve this, the optical lens is maintained so that there is permanent contact between the bottom of the lens and the mechanical blade. The lens, held in this manner, is immersion coated and then drawn out at a uniform or progressive drawing speed.

[0097] When the lens is being pulled out of the coating fluid, the coating film is "pulled out" by the mechanical blade due to surface tension (capillary force). As a result, the thickness of the coating layer, and the effect of that thickness on the apparent shape and refractive power of the lenslet, become uniform.

[0098] In other words, if such a mechanical blade is positioned to be in permanent contact with the optical lens, the thickness of the coating layer will be uniform as a result of the mechanical blade passively removing excess coating fluid while actively drawing the optical lens from the tank filled with coating fluid.

[0099] The thickness of the coating layer can be made even more uniform by actively rotating the optical lens, as shown in Figures 1 and 2.

[0100] Referring here to Figures 7A, 7B, 7C, 7D, 8A, 8B, and 8C, different diagrams of different types of mechanical blades (7) are shown, and it can be seen that the blades are in contact with the optical lens (6), which has a lenslet on one of its main surfaces, when the optical lens (6) is being drawn out of a tank filled with coating fluid.

[0101] Specifically, Figures 7A, 7B, and 7C show different diagrams of a straight mechanical blade without chamfering. Figure 7D shows a straight mechanical blade with chamfering. Figures 8A, 8B, and 8C show different diagrams of a curved mechanical blade, or the curved portion of a convex mechanical blade.

[0102] The mechanical blade is made of metal or other material that allows the flow of the coating fluid. The blade is narrow, for example, 0.5 mm to 2 mm wide, thereby preventing lateral defects such as marks from forming on the optical lens (6). Additional chamfering, as shown in Figure 7D, is possible to further reduce the width of the blade (7) at the contact point with the optical lens (6).

[0103] The blade may be straight, as shown in Figures 7A, 7B, 7C, and 7D. The blade may be curved, as shown in Figures 8A, 8B, and 8C, or it may be convex and concave, especially for lenses with thick edges, in order to ensure good contact between the blade (7) and the convex and concave surfaces of the lens (6). The inventions relating to this disclosure include the following aspects: <Aspect 1> A method for coating an optical lens having a principal surface that is at least partially covered with a lenslet, The aforementioned method, - Immersing the optical lens in the coating fluid, - The optical lens is withdrawn from the coating fluid and moved in a horizontal first direction (X 0 To reach an initial position (1) where the main surface faces toward ), - Drying the coating fluid that coats the optical lens, Includes, The method involves, after withdrawing the optical lens and before or during the drying of the coating fluid, moving the optical lens in the first direction (X 0 The final direction (X) has an angle of 80° to 100° relative to ). F This includes tilting the main surface to a final position (3) such that it faces upward toward the first direction (X 0 ) and the final direction (X F ) is the vertical plane (X 0 X F A method for determining ). <Aspect 2> Tilting the optical lens to the final position means The optical lens is moved from the initial position (1) to the vertical plane (X 0 X F ) in the second direction (X i The first part of the second i ) is the first direction (X 0 ) has an angle of 105° to 125°, and then, The optical lens is tilted from the intermediate position (2) to the final position (3), The method according to embodiment 1, including the method described in embodiment 1. <Aspect 3> The method according to embodiment 1 or 2, wherein the optical lens is withdrawn from the coating fluid at a constant withdrawal speed. <Aspect 4> The method according to embodiment 1 or 2, wherein the optical lens is withdrawn from the coating fluid at a gradually decreasing withdrawal speed. <Aspect 5> The method according to any one of embodiments 1 to 4, wherein the method includes waiting for a predetermined time equal to a maximum of 3 seconds after pulling out the optical lens and before tilting it, so that a portion of the coating fluid coating the optical lens can drip off. <Aspect 6> The method according to any one of embodiments 1 to 5, wherein the tilting of the optical lens is performed in accordance with a smooth, continuous movement. <Aspect 7> The method according to any one of embodiments 1 to 6, wherein drying the coating fluid coating the optical lens includes controlling the temperature on the main surface of the optical lens. <Aspect 8> The method according to any one of embodiments 1 to 7, wherein drying the coating fluid coating the optical lens includes controlling the gas flow rate on the main surface of the optical lens. <Pattern 9> A method for coating an optical lens having a main surface at least partially covered with a lenslet, wherein the method is: The optical lens is immersed in a coating fluid, The optical lens is withdrawn from the coating fluid and moved in a horizontal first direction (X 0 To reach an initial position (1) where the main surface faces toward ), This includes drying the coating fluid that coats the optical lens, The method includes removing a portion of the coating fluid from the optical lens by sliding the optical lens along a mechanical blade while the optical lens is being pulled out. <Aspect 10> The method involves, after withdrawing the optical lens and before or during the drying of the coating fluid, moving the optical lens in the first direction (X 0 The final direction (X) has an angle of 80° to 100° relative to ). F This includes tilting the main surface to a final position (3) such that it faces upward toward the first direction (X 0 ) and the final direction (X F ) is the vertical plane (X 0 X F The method according to aspect 9, which determines the following. <Aspect 11> A computer program comprising one or more stored instruction sequences that are accessible to a processing unit and, when executed by the processing unit, cause the processing unit to execute at least a portion of the method described in any one of embodiments 1 to 10. <Aspect 12> A non-temporary storage medium storing one or more stored instruction sequences of the computer program described in aspect 11.

Claims

1. A method for coating an optical lens having a principal surface that is at least partially covered with a lenslet, The aforementioned method, - Immersing the optical lens in the coating fluid, - To withdraw the optical lens from the coating fluid and bring it to an initial position where the main surface faces a horizontal first direction, - Drying the coating fluid that coats the optical lens, Includes, The method comprises, after the optical lens has been withdrawn and before or during the drying of the coating fluid, tilting the optical lens to a final position such that the main surface faces upward toward a final direction having an angle of 80° to 100° with respect to the first direction, wherein the first direction and the final direction define a vertical plane.

2. Tilting the optical lens to the final position means The optical lens is tilted from its initial position to an intermediate position determined such that its principal surface faces upward toward a second direction in the vertical plane, wherein the second direction has an angle of 105° to 125° with respect to the first direction, and then, The optical lens is tilted from the intermediate position to the final position, The method according to claim 1, including the method described in claim 1.

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

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

5. The method according to claim 1, further comprising waiting for a predetermined time equal to a maximum of 3 seconds after pulling out the optical lens and before tilting it, to allow a portion of the coating fluid coating the optical lens to drip off.

6. The method according to claim 1, wherein the tilting of the optical lens is performed in accordance with a smooth, continuous movement.

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

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

9. The method according to Claim 1, The method includes removing a portion of the coating fluid from the optical lens by sliding the optical lens along a mechanical blade while the optical lens is being pulled out.

10. A non-temporary computer-readable storage medium on which a program is recorded, the program being a program for implementing the method described in claim 1 when executed by a processor.

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