Electrically controlled optical device with front shell

Abstract

An electrically controlled optical device intended to be placed in front of a user's eye, the electrically controlled optical device being an ophthalmic device, the electrically controlled optical device comprising: a front shell defining a front surface and a back surface opposite the front surface, the front shell having a slab, at least one functional layer disposed on the back surface, and one primer layer, the primer layer being disposed between the at least one functional layer and the slab; and an electrically controlled objective lens facing the back surface of the front shell, the primer layer being adapted so that the electrically controlled optical device has mechanical resistance to an impact energy of at least 200 mJ.

Description

Technical Field

[0001] The present invention relates to an electrically controlled optical device.

[0002] The present invention further relates to a method of manufacturing an electrically controlled optical device.

Background Art

[0003] When manufacturing a new optical device, it is necessary to consider that in the case of an accidental impact with sufficient force, the optical element may be crushed. As a result, pieces of the optical element can break off and may damage the wearer's eye.

[0004] The selection of materials is important because it affects the weight and thickness of the optical element and its resistance to shock. There are two main types of transparent materials used in optical devices: organic materials such as polycarbonate and mineral glasses such as BK7.

[0005] In addition, eyewear having a specific function, such as an electrically controlled optical device, may need to apply a coating on the surface of the optical element. However, some coatings are known to have an adverse effect on the resistance to shock.

[0006] Restrictions are imposed on the material options due to the characteristics of the function to be applied and the conditions applied to the optical element during manufacturing and use.

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, there is a need for an electrically controlled optical device that does not damage the wearer's eye by crushing in the case of an accidental impact.

[0008] One of the objectives of the present invention is to provide such an apparatus.

[0009] Another object of the present invention is to provide a method for manufacturing such an apparatus. [Means for solving the problem]

[0010] To this end, the present invention proposes an electrically controlled optical device intended to be placed in front of the user's eyes, the electrically controlled optical device being an ophthalmic device, and the electrically controlled device is - A front shell defining a front surface and a back surface opposite to the front surface, wherein the front shell comprises a slab, at least one functional layer disposed on the back surface, and one primer layer, the primer layer being disposed between the at least one functional layer and the slab, - An electrically controlled objective lens facing the back surface of the front shell, It has, In this case, the primer layer is configured such that the electrically controlled device has mechanical resistance to an impact energy of at least 200 mJ.

[0011] Advantageously, the electrically controlled optical device of the present invention has improved shock resistance compared to known electrically controlled optical devices, due to the primer layer, without a significant increase in total thickness or weight.

[0012] Advantageously, the electrically controlled optical device according to the present invention can prevent the front shell from shattering or shattering when the front shell undergoes the FDA's drop ball test. In other words, since the front shell is not destroyed by this test and the 200 mJ impact energy, the present invention prevents fragments from being detached due to the primer layer, thereby protecting the user's eyes from any broken fragments of the front shell reaching them.

[0013] According to embodiments, the electrically controlled optical device according to the present invention may further have one or more of the following features, in any possible combination: - The slab is manufactured from an inorganic material and / or, - The front shell has a thickness of less than 1.7 mm, preferably less than 1.4 mm, more preferably less than 1.0 mm, and / or - The front shell is preferably configured to form a planar optical lens and / or a convex optical lens and / or a concave optical lens, which is an ophthalmic lens, and / or - The front shell, for example, has a light-refracting function adapted to the user's prescription, and / or - The primer layer has a thickness of less than 4 μm, particularly less than 3 μm, and / or less than 2 μm. - The primer layer has resistance to temperatures of at least 100°C, preferably 200°C, notably at least 250°C, and / or at least 300°C, - The primer layer is made from a polymer, sol-gel substance, or composite organic / inorganic substance, and / or - The primer layer is configured to form a refractive index adaptive layer, and / or - An electrically controlled optical device further comprises a back shell facing a front shell, the back shell being positioned such that an electrically controlled optical objective lens is positioned between the back shell and the front shell, and / or - The back surface of the front shell is concave, and / or - At least one functional layer has an anti-reflective coating and / or, - At least one functional layer preferably has a transparent conductive layer made from indium tin oxide, indium zinc oxide, aluminum zinc oxide, or gallium zinc oxide, and / or - An electrically controlled optical objective lens has an element positioned in electrical contact with a conductive layer, the element being selected from the group consisting of a liquid crystal layer, an electrochromic material layer, and / or - An electrically controlled optical objective lens has further elements selected from the group consisting of an electrically controlled active lens, a spatial light modulator, a waveguide, and a holographic structure, and / or - An electrically controlled optical device, for example, has a light refraction function adapted to the user's prescription, and / or - An electrically controlled optical device has, for example, a transmission function adapted to actively protect from glare, and / or - The electrically controlled optical device is a head-mounted device, preferably a head-mounted display.

[0014] Furthermore, the present invention proposes a method for manufacturing a front shell for an electrically controlled optical device intended to be placed in front of the user's eyes, and the method is: - A step of providing a slab having a front and a back surface, - A step of depositing a primer layer on at least the back surface of the slab, - A step of curing the primer layer deposited on the slab at the curing temperature, - The step of applying at least one functional layer on a primer layer such that at least one functional layer is positioned on at least the back surface of the front shell, It has the following steps.

[0015] According to embodiments, the method for manufacturing an electrically controlled optical device according to the present invention may further have one or more of the following features in any possible combination: - At least one functional layer is applied through a sputtering method at a predetermined sputtering temperature, and / or - The established sputtering temperature is 100°C, preferably above 200°C, particularly above 250°C, and advantageously 300°C or higher.

[0016] Hereinafter, the embodiments of the present invention will be described only as examples and with reference to the following drawings.

Brief Description of the Drawings

[0017] [Figure 1] It is a schematic side view of an electrically controlled optical device according to the present invention. [Figure 1B] It is a schematic side view of an electrically controlled optical device according to the present invention. [Figure 2] It is a flowchart of various steps of a method for manufacturing an electrically controlled optical device according to the present invention. [Figure 3] It is a flowchart of various steps of a method for manufacturing an electrically controlled optical device according to an embodiment of the present invention. [Figure 4] It is a flowchart of various steps of a method for manufacturing an electrically controlled optical device according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0018] The elements in the figures are shown for the purpose of simplicity and clarity, and the drawn scales are not necessarily accurate. For example, the dimensions of some of the elements in the figures may be exaggerated in relation to other elements to assist in the understanding of the embodiments of the present invention. Also, unless otherwise specified, each surface of the elements represented in the figures as concave may be convex, and vice versa.

[0019] The present invention relates to an electrically controlled optical device intended to be placed in front of a user's eye, and the electrically controlled optical device is an ophthalmic device.

[0020] The present invention relates to any type of electrically controlled optical device, including active lenses, virtual reality devices, augmented reality devices, LCD displays, e-focus lenses (known as lenses including active focus or dynamic vision correction), and active polarizers. The electrically controlled optical device may have any optical elements that can be included in eyewear, such as solar lenses, electrochromic cells, waveguides, and holographic mirrors. The electrically controlled optical device may have a standard or specific frame, such as an electronic frame.

[0021] In some embodiments, the electrically controlled optical device is a head-mounted device, preferably a head-mounted display.

[0022] In some embodiments, the electrically controlled optical device has, for example, a light refraction function adapted to the user's prescription. In embodiments, the light refraction function can be controlled by the electrically controlled optical device.

[0023] In some embodiments, electrically controlled optical devices have a transmission function adapted, for example, to actively protect from glare. This function can be implemented by an electrochromic device.

[0024] As shown in Figures 1 and 1B, the electrically controlled optical device according to the present invention comprises at least, - Front shell 2 (shown as striped in Figures 1 and 1B), - An electrically controlled objective lens 12 (shown in gray in Figures 1 and 1B), It has.

[0025] According to the present invention, the front shell 2 defines a front surface 4 and a back surface 6 opposite to the front surface 4. The back surface 6 corresponds to the surface of the front shell 2 that is intended to be closest to the user's eye when the optical lens is positioned in front of the user's eye.

[0026] The front shell 2 has a slab 3.

[0027] In the sense of the present invention, slab 3 defines a front surface oriented toward the front surface of the front shell and a back surface oriented toward the rear surface of the front shell. Slab 3 may be flat or curved.

[0028] In embodiments, slab 3 is manufactured from an inorganic material, in particular, mineral glass. Advantageously, inorganic materials can withstand relatively high temperatures compared to organic materials such as polyurethane, or acrylic polymers, copolymers, or mixtures thereof. Advantageously, inorganic materials are resistant to manufacturing conditions involving heating at temperatures above 250°C. Advantageously, mineral glass is a very transparent material and provides a very good barrier to oxygen and moisture.

[0029] In the embodiments, the front shell 2 has a thickness of less than 1.7 mm, preferably less than 1.4 mm. In the embodiments, the front shell 2 has a thickness of more than 0.1 mm, preferably more than 0.5 mm. Advantageously, the weight of the electrically controlled optical device is minimized while maintaining sufficient resistance to shock.

[0030] In the embodiment, the front shell 2 is preferably configured to form a planar optical lens and / or a convex optical lens and / or a concave optical lens, which are ophthalmic lenses.

[0031] In this embodiment, the back surface 6 of the front shell 2 is concave.

[0032] In the embodiment, the front shell 2 has, for example, a light refraction function adapted to the user's prescription. Advantageously, the front shell 2 combines the function of correcting the user's visual acuity within a single objective lens with the function of protecting the electrically controlled objective lens 12 from impact.

[0033] The term "prescription" should be understood to mean a set of optical properties, such as refractive power, astigmatism, prismatic deviation, and, where appropriate, add power, determined by an ophthalmologist or optometrist to correct a user's visual impairment using a lens positioned in front of the user's eye.

[0034] For example, a prescription for progressive multifocal lenses includes refractive power and astigmatism values ​​at the point of visual acuity at distance, and, as appropriate, an add power value. The prescription data may include data for emmetropic eyes.

[0035] The front shell 2 may have a passive waveguide. Light coupled into the waveguide propagates along the waveguide by total internal reflection. The waveguide has two opposite transparent walls with a gap, which may be hollow or filled with a substrate. The length of the gap between the two opposite walls is determined so that light of a selected wavelength can propagate through the waveguide by repeated reflection off both opposite walls.

[0036] The front shell 2 may have a passive holographic mirror. The holographic mirror is defined as one that is recorded using a holographic process. The mirror is used to reflect a light beam generated from an image source to produce an image visualization by the wearer. The holographic mirror is not used to reconstruct the recorded holographic image (as in conventional hologram observation). Due to the recording, the mirror is equipped with an optical function that, as appropriate, can alter the wavefront of the light beam originating from the image source upon reflection onto the mirror. This allows for a substantial correction of the wearer's vision because the optical lens containing the holographic mirror can alter the light beam that generates the image in the wearer's eye.

[0037] When passive elements (waveguides or holographic mirrors) are used, the electrically controlled objective lens of the present invention can be positioned in front of the passive elements to improve the contrast of the image obtained by the passive elements.

[0038] According to the present invention, the front shell 2 has at least one functional layer 8 disposed on the back surface 6.

[0039] At least one functional layer 8 may have an anti-reflective coating and / or a transparent conductive layer, preferably made from indium tin oxide, indium zinc oxide, aluminum zinc oxide, or gallium zinc oxide.

[0040] According to the present invention, the front shell 2 has one primer layer 10 disposed between at least one functional layer 8 and the back surface 6.

[0041] In this embodiment, the primer layer 10 is adapted such that the electrically controlled optical device has mechanical resistance to an impact energy of at least 200 mJ.

[0042] Impact testing can be performed. The impact test may be a so-called "drop ball test" that complies with the impact resistance requirements issued by the Food and Drug Administration (FDA). In the drop ball test, a 5 / 8-inch (1.5875 cm) steel ball weighing approximately 0.56 ounces (15.87573 g) is dropped from a height of 50 inches (127 cm) onto the horizontally convex upper surface of an electrically controlled optical device. The ball will strike within a circle with a diameter of 5 / 8 inch (1.5875 cm) positioned at the geometric center of the electrically controlled optical device.

[0043] The ball is dropped through a tube extending approximately 4 inches (10.16 cm) within the optical device, allowing it to be guided without restriction during its descent. To pass the ball drop test, the optical device must not be damaged.

[0044] An optical device is considered to have broken into two or more separate pieces, if present, throughout its entire thickness, including the laminar layer, and across its entire diameter, or to have been disintegrated when any material visible to the naked eye is removed from the surface of the optical device intended to face the eye when the optical device is positioned in front of the eye.

[0045] The electrically controlled optical device according to the present invention has passed the ball-dropping test because the front shell 2 does not break or shatter due to the primer layer 10.

[0046] To comply with FDA standards, manufacturing samples must be tested and have a failure rate of less than 6.5%.

[0047] In the embodiment, the primer layer 10 has a thickness of less than 4 μm, particularly less than 3 μm, and preferably less than 2 μm. Advantageously, the thickness and weight of the primer layer are negligible over the total thickness and weight of the electrically controlled optical device. Advantageously, minimizing the thickness of the primer layer 10 contributes to minimizing haze on the electrically controlled optical device.

[0048] In the embodiment, the primer layer 10 has a thickness of more than 0.1 μm, particularly more than 0.2 μm, and preferably more than 0.4 μm.

[0049] In embodiments, the primer layer 10 has resistance to temperatures of at least 100°C, preferably 200°C, particularly at least 250°C, and advantageously at least 300°C. Advantageously, during manufacturing, at least one functional layer 8 can be applied through a sputtering method at a predetermined sputtering temperature in which the primer layer 10 remains unchanged. Advantageously, applying at least one functional layer 8 at such high temperatures contributes to minimizing haze on the optical device.

[0050] In the embodiment, the primer layer 10 is manufactured from a material that is resistant to all process conditions experienced by the mineral glass shell during manufacturing, including high temperatures above 200°C, vacuum, and cleaning processes.

[0051] In embodiments, the primer layer 10 is manufactured from a polymer, sol-gel substance, or composite organic / inorganic substance. Possible materials include silicone resins, polyesters, polyimide polysiloxanes, polytitanocarbosilanes, alkoxysilanes, or mixtures or copolymers of these materials. Specifically, colloids, which are metal oxide particles such as graphene, silicon dioxide particles, titanium dioxide particles, or zirconium oxide particles, can be added to the material. The composition may be in a solvent or in a water-based solution. Some of these can also be applied by dry deposition processes, such as plasma-enhanced deposition or chemical deposition. Several additives can be added to the formulation, such as surfactants or co-solvents to improve the coating process, thermal or UV crosslinking agents to improve its mechanical properties, antioxidants or UV absorbers to improve its thermal or photostability, or to modify its optical properties, such as its refractive index or UV absorption.

[0052] The primer can be cured by heat or UV. In some cases, it may be necessary to cure the primer in an inert atmosphere, such as under nitrogen, to avoid yellowing of the primer during the curing step.

[0053] In this embodiment, the primer layer 10 is configured to form a refractive index adaptive layer between the slab 3 and the functional layer 8. In practice, if the refractive indices of the slab 3 and the functional layer 8 are different, some degree of light reflection will occur at the interface. By selecting the refractive index of the primer layer 10 to be between the refractive indices of the slab 3 and the functional layer 8, light reflection can be reduced, thereby improving the overall transparency of the electrically controlled optical device.

[0054] In one embodiment, the primer layer 10 may extend over the back surface 6 of the slab 3. Alternatively, the front shell 2 may have a second primer layer (not shown) positioned on the front surface 4.

[0055] The primer layer must actually support the heat treatment that will be applied in the functional layer deposition process. In particular, when a highly conductive coating is required, a primer layer with heat resistance is preferred because these are typically applied at temperatures of 150°C or above 200°C.

[0056] For example, silicone resins are known to produce thin films with excellent thermal resistance and adjustable flexibility and hardness due to their three-dimensional structure. Silicone resins with methyl and phenyl substituents, in particular, exhibit excellent thermal resistance. For instance, Shin Etsu's commercially available resin (KR300), based on a methyl / phenyl silicone component, was used as a primer. This resin was deposited by spin coating on the concave side of a glass shell with a thickness of 0.85 mm. The resin thickness was 3 μm. An ITO coating was deposited on this silicone layer by sputtering to obtain a surface sheet resistance of approximately 10 Ω / □ (ohm / square). Excellent impact resistance was obtained. Without this primer layer, the glass shell would not have passed the FDA drop ball test. With this primer layer, not only the front shell, but also cells manufactured to have a front shell coated with this primer, successfully pass the FDA drop ball test.

[0057] Furthermore, polyimides are also interesting as primer materials because some of them can withstand high curing temperatures and processes of 200°C, 250°C, 300°C, or even higher. For example, some polyimide resins from Nissan Chemical Industries, which have the trademark Sunever, could be used.

[0058] Furthermore, several polyester resins can also be used. Some of these have high heat resistance. Polyvinyl ester resins generally have greater temperature resistance than unsaturated polyester resins. In addition, some fluorosilicone-modified polyester resins are known to have greater heat resistance than polyester resins alone.

[0059] Furthermore, other complex organic-inorganic hybrid materials are also suitable primer materials. These can actually possess significant temperature resistance. For example, a composition in methanol containing 20-30% glycidoxypropyltrimethoxysilane, 10-20% tetraethoxysilane, and a catalyst can be used.

[0060] According to the present invention, the electrically controlled objective lens 12 is positioned opposite the back surface of the front shell 2.

[0061] In this embodiment, the electrically controlled optical objective lens 12 has an element positioned in electrical contact with a conductive layer.

[0062] The element may have an electrically controlled active lens. The element may have a refractive function that can be adapted to the user's prescription data.

[0063] The element may have an electrochromic material layer of an electrochromic cell between two transparent supports, in which case one of the transparent supports is the front shell 2. The electrochromic cell has at least one electrochromic dye compound having an oxidation potential and experiencing a change in one optical property when an electric field is applied between the transparent supports using at least two transparent electrodes. For example, the dye may be uncolored in one oxidation state and yellow, green, blue, or purple in another oxidation state. The oxidation state of the dye can be controlled by applying an electric field, in other words, a voltage, between the electrodes and to the electrochromic dye compound.

[0064] The element may have a liquid crystal layer of a liquid crystal cell having at least one liquid crystal material between two transparent supports, in which case one of the transparent supports is the front shell 2. For example, at least one of the transparent supports, such as both of the transparent supports, has at least one transparent electrode. The liquid crystal cell changes light based on the optical properties of the liquid crystal material, in the presence or absence of an electric field, in other words, a voltage, applied between the electrodes and to the liquid crystal material.

[0065] The element may have an electrically operated waveguide. The waveguide has two opposite transparent walls with a gap, which may be hollow or filled with a substrate. The length of the gap between the two opposite walls is determined so that light of a selected wavelength can propagate through the waveguide by iteratively reflecting off both opposite walls. The electrically operated waveguide may have one or more areas of tunable optical properties, such as refractive index, phase, reflectance (value, angle, wavelength, or spectral curve), and transmittance. For example, each wall may have a transparent electrode, the gap may be filled with a substrate, and the active optical waveguide changes the propagation of light based on the refractive index of the substrate, in the presence or absence of an electric field, in other words, a voltage, applied between the electrodes and to the substrate. The length of the gap may also be controllable.

[0066] The element may have an electrically operated spatial light modulator.

[0067] The element may have an electrically operated holographic mirror. The holographic mirror may have one or more areas of tunable optical properties, such as values ​​of refractive index, phase, reflectance (value, angle, wavelength, or spectral curve), transmittance, etc.

[0068] As shown in Figure 1B, the electrically controlled optical device may further have a back shell 14 facing the front shell 2, and the back shell is configured such that an electrically controlled optical objective lens 12 is positioned between the back shell 14 and the front shell 2.

[0069] Furthermore, it is naturally possible to apply any of the above-described features, or any combination thereof, to the backshell 14 with respect to the front cell 2.

[0070] Another object of the present invention is a method for manufacturing a front shell 2 of an electrically controlled optical device intended to be positioned in front of the user's eyes.

[0071] The front shell 2 defines the front 4 and the back 6, which is opposite the front 4.

[0072] As shown in Figure 2, the method is: - Step S1 provides slab 3, - Step S2 involves depositing a primer layer 10 on at least the back surface of the slab 3, - Step S4 involves curing the primer layer 10 deposited on the slab 3 at the curing temperature, - Step S5 of applying at least one functional layer 8 on the primer layer 10 such that at least one functional layer 8 is positioned on at least the back surface 6 of the front shell 2, It has the following steps.

[0073] Step S2, which involves depositing the primer layer 10, can be carried out by a wet coating process such as spin coating, dip coating, spray coating, slit coating, inkjet coating, or drop jetting.

[0074] Furthermore, in step S2, in which the primer layer 10 is deposited, the primer layer 10 can also be deposited on the front surface 4 of the front shell 2.

[0075] In step S4, which involves curing the primer layer 10 deposited on the front shell 2, the curing temperature may be greater than 200°C, preferably greater than 250°C, and more preferably greater than 300°C.

[0076] In step S5, in which at least one functional layer 8 is applied, the at least one functional layer 8 can be applied by a sputtering method at a predetermined sputtering temperature. In embodiments, the predetermined sputtering temperature is greater than 200°C, particularly greater than 250°C, and advantageously greater than 300°C.

[0077] Alternatively, at least one functional layer 8 can be applied via a vapor deposition method.

[0078] As shown in Figure 3, the method may have a pre-curing step S3 before the curing step S4, in which case the primer layer 10 deposited on the front shell 2 is pre-cured at 100°C for, for example, 15 minutes. Advantageously, in cases where the primer layer is based on a solvent or water-based volume, most of the solvent is removed in the pre-curing step.

[0079] Alternatively, pre-curing can be achieved by UV exposure to obtain a first level of crosslinking in the primer, which allows for easy handling or gelling of the primer. The final curing step completes the crosslinking and / or polymerization of the primer.

[0080] As shown in Figure 4, the method may have a post-curing step S6 after step S5, in which at least one functional layer 8 is applied. The post-curing step S6 may include maintaining the front shell 2, having the slab 3, primer layer 10, and at least one functional layer 8, at a temperature similar to or slightly lower than the curing temperature for a long period of time, such as one hour or more. The post-curing step S6 is also usually performed when an electrically controlled optical device has a back shell 14. Advantageously, the electrically controlled optical device results in improved transparency properties.

[0081] The method may include both a pre-curing step S3 and a post-curing step S6.

[0082] The present invention has been described above with the support of embodiments, without being limited by the general concept of the invention.

[0083] Those skilled in the art will see many further modifications and variations by referring to the above exemplary embodiments, which are provided only as examples and are not intended to limit the scope of the invention as determined solely by the appended claims.

[0084] In the claims, the term “having” does not preclude other elements or steps, and the indefinite article “one” does not preclude the plural. The fact that different features are described in different dependent claims does not, in itself, imply that combinations of these features cannot be used advantageously. Any reference numerals in the claims should not be construed as limiting the scope of the invention.

Claims

1. An electrically controlled optical device intended to be placed in front of the user's eyes, wherein the electrically controlled optical device is an ophthalmic device, and the electrically controlled optical device is A front shell defining a front surface and a back surface opposite to the front surface, wherein the front shell comprises a slab, at least one functional layer disposed on the back surface, and one primer layer, the primer layer disposed between the at least one functional layer and the slab, An electrically controlled objective lens facing the back surface of the front shell, It has, The primer layer is configured such that the electrically controlled optical device has mechanical resistance to an impact energy of at least 200 mJ. The thickness of the front shell is less than 1.7 mm. The aforementioned primer layer is configured to form a refractive index-adaptive layer in an optical device.

2. The optical apparatus according to claim 1, wherein the slab is manufactured from an inorganic material.

3. The optical apparatus according to claim 1 or 2, wherein the primer layer has a thickness of less than 4 μm.

4. The optical apparatus according to claim 1 or 2, wherein the primer layer has resistance to a temperature of at least 100°C.

5. The optical apparatus according to claim 1 or 2, wherein the primer layer is manufactured from a polymer, a sol-gel substance, or a composite organic / inorganic substance.

6. The optical device according to claim 1 or 2, wherein the electrically controlled optical device further comprises a back shell facing the front shell, the back shell being configured such that the electrically controlled optical objective lens is positioned between the back shell and the front shell, and the at least one functional layer is a transparent conductive layer.

7. The optical apparatus according to claim 6, wherein the electrically controlled optical objective lens has an element arranged in electrical contact with the transparent conductive layer, and the element is selected from the group consisting of a liquid crystal layer and an electrochromic material layer.

8. The optical device according to claim 1 or 2, wherein the back surface of the front shell is concave.

9. The optical apparatus according to claim 1 or 2, wherein the electrically controlled optical apparatus has a transmission function.

10. A method for manufacturing a front shell for an electrically controlled optical device intended to be positioned in front of a user's eyes, according to any one of claims 1 to 9, A step of providing a slab having a front and a back surface, The steps include depositing a primer layer on at least the back surface of the slab, The steps include curing the primer layer deposited on the slab at the curing temperature, A method comprising the step of depositing the at least one functional layer on the primer layer such that the at least one functional layer is positioned on at least the back surface of the front shell.

11. The method according to claim 10, wherein the at least one functional layer is deposited by a sputtering method at a predetermined sputtering temperature.

12. The method according to claim 11, wherein the predetermined sputtering temperature is at least 100°C.

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