Optical lens

Abstract

1. An optical lens intended to be placed in front of a wearer's eye, the optical lens having a front surface and a rear surface, the rear surface being the surface intended to be closest to the wearer's eye when the optical lens is placed in front of the wearer's eye, the optical lens having a mineral glass element on its front surface, and further comprising eye protection configured to prevent any fragments of the mineral glass element from reaching the wearer's eye in the event of breakage of the element, the eye protection comprising a polymer wafer placed on the rear surface.

Description

Technical Field

[0001] The present invention relates to an optical lens intended to be placed in front of the eyes of a wearer and having a front surface and a rear surface, the rear surface being the surface intended to be closest to the eyes of the wearer when the optical lens is placed in front of the eyes of the wearer, and relates to an optical device comprising a pair of such optical lenses adapted to be attached to an eyeglass frame.

Background Art

[0002] When manufacturing eyeglasses, the choice of material is important as it affects the weight and thickness of the lens and its resistance to impact. There are two main types of materials used for optical lenses, organic materials such as polycarbonate and mineral glass such as BK7.

[0003] Optical lenses made of polycarbonate have excellent impact resistance. However, not all types of optical lenses are made from polycarbonate. For example, some lens manufacturing methods may require reaching temperatures at which polycarbonate or other organic materials may deteriorate. The lifespan of the optical lens may be shortened. Therefore, mineral glass is sometimes the only available option.

[0004] However, in the case of an accidental collision with sufficient force, mineral glass may break. As a result, pieces of mineral glass may flake off and can potentially damage the eyes of the wearer.

[0005] Therefore, there is a need for optical lenses comprising mineral glass that do not damage the eyes of the wearer by shattering in the case of an accidental collision.

[0006] One object of the present invention is to provide such an optical lens.

Summary of the Invention

Means for Solving the Problems

[0007] To achieve this objective, the invention proposes an optical lens having a front and a rear surface, intended to be positioned in front of the wearer's eyes, wherein the rear surface is the surface intended to be closest to the wearer's eyes when the optical lens is positioned in front of the wearer's eyes, the optical lens having a mineral glass element on the front surface, and further comprising an eye protection device configured to prevent any fragments of the mineral glass element from reaching the wearer's eyes in the event of breakage, the eye protection device comprising a polymer wafer positioned on the rear surface.

[0008] Advantageously, the optical lens according to the invention can prevent glass fragments from detaching, and therefore protects the polymer wafer from broken glass fragments reaching the wearer's eyes.

[0009] According to further embodiments that can be considered individually or in combination, - The polymer wafer is a plano wafer and / or, - The polymer wafer has an average thickness of 10 μm or more, preferably 50 μm or more, more preferably 75 μm or more, even more preferably 300 μm or more, and most preferably 700 μm or more, and / or - The polymer wafer has an average thickness of 2 mm or less, preferably 1.5 mm or less, more preferably 1 mm or less, and / or - The polymer wafer has a front and a rear surface, the rear surface corresponding to the rear surface of the optical lens, and / or the front surface of the polymer wafer is bonded to a mineral glass element, and / or - The polymer wafer is made of a transparent material such as a thermoplastic or thermosetting material, for example, a transparent material suitable for ophthalmic lenses, and / or - The polymer wafer has scratch-resistant, antistatic, antifouling, and / or anti-fogging properties, and / or - The polymer wafer has, for example, an anti-reflective reflective function, and / or - The polymer wafer has, for example, blue light blocking and / or UV protection light absorption properties, and / or the polymer wafer has a specific color, and / or - The polymer wafer has a polarizing function and / or, - The polymer wafer has photochromic properties and / or, - The polymer wafer extends over the edge of the optical lens to protect the edge of the optical lens, and / or - The polymer wafer edge is provided with a bevel that is adapted to allow the mounting of optical lenses within an eyeglass frame, and / or - The optical lens comprises a second polymer wafer positioned at least in front of the optical lens, and / or - The mineral glass element comprises at least an electroactive element such as an electrochromic cell and / or a liquid crystal cell and / or a waveguide and / or a holographic mirror, and / or - The mineral glass element is configured to break at least partially when a steel ball drop test is applied to the lens, and / or - Mineral glass elements, for example, have a refractive function that conforms to the wearer's prescription.

[0010] The invention also relates to an optical instrument comprising a pair of optical lenses attached to an eyeglass frame.

[0011] Other features and advantages of the invention will become more apparent from the appended claims and from the following description of some embodiments given as examples without limitation with reference to the following drawings. [Brief explanation of the drawing]

[0012] [Figure 1-4] Figures 1-4 are cross-sectional views of an optical lens according to an embodiment of the invention. [Figure 5] Figure 5 shows an optical device according to one embodiment of the invention.

[0013] The components in the drawings are shown for simplification and clarity and are not necessarily drawn to an exact scale. For example, the dimensions of some components in the drawings may be exaggerated compared to others to help improve the understanding of embodiments of the invention. Unless otherwise specified, each surface of a component shown as concave in the drawings may also be convex, and vice versa. [Modes for carrying out the invention]

[0014] The present invention relates to an optical lens 2 having a front surface 4 and a rear surface 6, which is intended to be positioned in front of the wearer's eyes, wherein the rear surface 6 is the surface that is closest to the wearer's eyes when the optical lens is positioned.

[0015] Within the framework of the invention, the term “optical lens” should be understood to mean any known type of optical lens intended to be placed in front of the wearer’s eye. An optical lens may also refer to a non-corrective optical lens, or a corrective optical lens, also known as an ophthalmic lens, such as a progressive addition lens, monofocal lens, or multifocal lens.

[0016] Ophthalmic lenses have refractive properties that can be adjusted to match the wearer's prescription data.

[0017] The term "prescription" should be understood to mean, for example, the set of refractive power, astigmatism, prism deflection, and, if applicable, additional optical properties specified by an ophthalmologist or optometrist to correct the wearer's visual impairment by a lens positioned in front of the eye.

[0018] For example, a prescription for a progressive add-on lens includes refractive power and astigmatism values ​​at the distance, and additional values ​​as needed. The prescription data may also include data for emmetropic eyes.

[0019] As shown in FIGS. 1 to 4, the optical lens 2 includes a mineral glass element 8 such as a silicate-based glass element on the front surface 4. In the figure, the mineral glass element is represented as a dotted surface.

[0020] The mineral glass element 8 has a front surface 10 and a rear surface 12. The front surface 4 of the optical lens 2 includes at least a part of the front surface 10 of the mineral glass element 8.

[0021] The mineral glass element 8 may include a passive waveguide. The light coupled to the waveguide propagates along the waveguide by total reflection. The waveguide includes two opposing transparent walls with a gap filled with a hollow or a substrate. The length of the gap between the two opposing walls is specified so that light of a selected wavelength can propagate through the waveguide by reflecting many times on both opposing walls.

[0022] The mineral glass element 8 may include a passive holographic mirror. The holographic mirror is defined as being recorded using a holographic process. The mirror is used to reflect light rays generated from an image source so as to cause visualization of an image by the wearer. The holographic mirror is not used to reconstruct a recorded holographic image (as in the case of a conventional hologram display). By recording, when the mirror can be applied to modify the wavefront of light rays generated from the image source, an optical function possible upon reflection on the mirror is imparted. Thereby, since the optical lens incorporating the holographic mirror can modify the light rays generating an image in the wearer's eye, it is possible to correct the virtual vision of the wearer.

[0023] As shown in FIG. 2, the mineral glass element 8 may include one or more electroactive elements 14. The electroactive element 14 is an element having at least one changeable optical property by application of electrical energy.

[0024] The electroactive element 14 may be embedded inside the mineral glass element 8 or may be formed from the mineral glass element 8. The electroactive element 14 may be adapted to the edge of the mineral glass element 8 or to its front face 10 or rear face 12.

[0025] The electroactive element 14 may be, for example, an electrochromic cell between two transparent supports made of a substrate. The electrochromic cell has an oxidation potential and comprises at least one electrochromic dye compound that undergoes one optical property change upon application of an electric field between transparent supports using at least two transparent electrodes. For example, the dye may be colorless in an oxidized state and yellow, green, blue or purple in another oxidized state. The oxidation state of the dye may be controlled by applying an electric field, in other words a voltage, between the electrodes and to the electrochromic dye compound.

[0026] The electroactive element 14 may be a liquid crystal cell. The liquid crystal cell comprises, for example, at least one liquid crystalline substance between two transparent supports made of a substrate. At least one transparent support, for example both transparent supports, comprises at least one transparent electrode. The liquid crystal cell changes light based on the optical properties of the liquid crystalline substance depending on the presence or absence of an electric field, in other words a voltage, applied between the electrodes and to the liquid crystalline substance.

[0027] The electroactive element 14 may be an electroactive waveguide. The waveguide comprises two opposing transparent walls with a gap that is hollow or filled with a substrate. The length of the gap between the two opposing walls is specified such that light of a selected wavelength may propagate through the waveguide by reflecting multiple times off both opposing walls. The electroactive waveguide may comprise one or more regions of adjustable optical properties such as values of refractive index, phase, reflectivity (value, angle, wavelength, or spectral curve), transmittance, etc. For example, the walls may each comprise a transparent electrode and the gap is filled with a substrate, and in the case of transparent electrodes, the active optical waveguide changes the propagation of light based on the refractive index of the substrate depending on 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 commanded.

[0028] The electroactive element 14 may be an electroactive holographic mirror. The holographic mirror may have one or more ranges of adjustable optical properties such as refractive index, phase, reflectance (value, angle, wavelength, or spectral curve), transmittance, etc. The mineral glass element 8 may have a refractive function that can be adapted to the wearer's prescription data.

[0029] As shown in Figures 1-4, the optical lens further includes an eye protector 16 configured to prevent any fragments of the mineral glass element 8 from reaching the wearer's eye in the event of breakage of the mineral glass element 8. The eye protector 16 comprises a polymer wafer 18 positioned on the rear surface 6 of the optical lens 2. In the figures, the polymer wafer 18 is represented as a vertically striped surface.

[0030] The polymer wafer 18 has a front surface 20 and a rear surface 22. The rear surface 6 of the optical lens 2 includes at least a portion of the rear surface 22 of the polymer wafer.

[0031] The polymer wafer 18 prevents fragments of the mineral glass element 8 from detaching if the mineral glass element 8 is at least partially damaged when the optical lens is subjected to an impact.

[0032] An impact test may be performed. The impact test may be a so-called "steel ball drop test." According to the steel ball drop 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) above the convex top surface of the lens. The ball must hit within a circle with a diameter of 5 / 8 inch (1.5875 cm) located at the geometric center of the lens.

[0033] The ball is guided, but may not be restricted, by being dropped through a tube that extends approximately 4 inches (10.16 cm) within the lens. To pass the steel ball drop test, the optical lens must not be damaged.

[0034] An optical lens is considered broken if it is cracked through its entire thickness, including any layered layers, and across its entire diameter, or if any visible lens material is separated from the surface of the lens that is intended to face the eye when the lens is positioned in front of the eye.

[0035] Advantageously, the optical lens 2 of the invention, for eye protection 16 equipped with a polymer wafer 18, passes the steel ball drop test even if the mineral glass element 8 is broken.

[0036] According to embodiments of the invention, the polymer wafer 18 may have an average thickness of 10 μm or more, preferably 50 μm or more, more preferably 75 μm or more, even more preferably 300 μm or more, and most preferably 700 μm or more, and 2 mm or less, preferably 1.5 mm or less, and more preferably 1 mm or less. The inventors observed that a polycarbonate polymer wafer 18 with an average thickness of 300 μm or more greatly improves the impact resistance of the optical lens 2.

[0037] Furthermore, the polymer wafer 18 with an average thickness of approximately 800 μm further improves the optical performance of the optical lens 2. In fact, when using a 300 μm wafer, some optical distortion may occur due to wafer deformation during manufacturing, especially during the coating process.

[0038] In a preferred embodiment, the rear surface 22 of the polymer wafer 18 corresponds to the rear surface 6 of the optical lens.

[0039] The front surface 20 of the polymer wafer 18 may be bonded to the mineral glass element 8, for example, to the rear surface 12 of the mineral glass element 8. For example, the adhesive may be spread on the rear surface 12 of the mineral glass element 8, and then the polymer wafer 18 may be dropped onto the spread adhesive. To avoid deformation of the polymer wafer 18 caused by the weight of the mineral glass element 8, the polymer wafer 18 may be placed on the mineral glass element 18 during the bonding process.

[0040] The polymer wafer 18 may be bonded to the mineral glass element 8 by a liquid adhesive or a pressure-sensitive adhesive (PSA). The adhesive composition may be selected based on the material of the polymer wafer 18 so as to bond with the mineral glass element. In the case of wafers obtained from a film, PSA is preferred.

[0041] The bonding may be performed over the entire surface of the polymer wafer 18 or only around the perimeter of the polymer wafer 18. In this second case, a spacer may be introduced into the liquid adhesive to ensure a uniform thickness of adhesive around the entire perimeter of the polymer wafer 18.

[0042] Plasma or corona treatment may be applied to the mineral glass element 8. Advantageously, this ensures the spreading of the adhesive on the mineral glass element 8 and the polymer wafer 18, as well as the adhesion between the mineral glass element 8 and the polymer wafer 18.

[0043] An adhesive primer may be used during the bonding process to promote adhesion.

[0044] The polymer wafer 18 may be trimmed or cut before being bonded to the mineral glass element 8. If the polymer wafer 18 is obtained from a film, the cutting of the polymer wafer 18 may be performed using a laser. Bonding is particularly advantageous because the polymer wafer 18 and the mineral glass element 8 remain integrated for a very long time, and unlike other fastening means, the adhesive is transparent and therefore does not restrict the wearer's field of vision. Preferably, the adhesive may take the form of a layer having a uniform thickness across the front surface 20 of the polymer wafer 18.

[0045] Alternatively, the polymer wafer 18 may be bonded to the mineral glass element 8 by any other method known to those skilled in the art.

[0046] The polymer wafer 18 comprises at least one base wafer. The polymer wafer may also comprise one or more functional layers supported by the base wafer.

[0047] The base wafer can be obtained by casting, injection molding, or surfacing, starting from a thicker blank. The base wafer can also be obtained from a film. This film can itself be obtained by various techniques, for example, by extrusion, followed by uniaxial or biaxial stretching. The film is then thermoformed to give the wafer a radius of curvature that matches the radius of curvature of the mineral glass to which the wafer is bonded.

[0048] The base wafer can also be obtained by welding layers using conventional welding techniques known to those skilled in the art, such as immersion coating, spin coating, spray coating, inkjet coating, etc., and optionally by subsequent drying and / or polymerization steps under UV or visible light irradiation, or by heat treatment.

[0049] Finally, the base wafer can be manufactured directly on mineral glass using additive manufacturing technology.

[0050] The polymer wafer 18 may be laminated on a mineral glass element 8. The lamination method may include a lamination step during which a specific holding system for the mineral glass element 8 is used, and the holding system is configured to avoid damage around the mineral glass element 8 during the lamination step.

[0051] As a non-limiting instruction, the base wafer material may be selected from materials for optical, particularly ophthalmic optics. The material may be selected from thermoplastic or thermosetting materials such as, for example, polycarbonates, polyamides, polyimides, polysulfones, polyethylene terephthalate and polycarbonate copolymers, polyolefins, particularly polynorbornene, diethylene glycol bis(allyl carbonate) polymers and copolymers, (meth)acrylic polymers and copolymers, particularly polymers derived from bisphenol A and (meth)acrylic copolymers, thio(meth)acrylic polymers and copolymers, urethanes and thiourethane polymers and copolymers, epoxy polymers and copolymers, episulfide polymers and copolymers, cellulose polymers and copolymers, particularly cellulose triacetate, vinyl polymers and copolymers, particularly polyvinyl chloride, urethane polymers and copolymers, particularly thermoplastic polyurethanes, and siloxane polymers and copolymers.

[0052] According to one embodiment, if the base wafer is obtained from a film, the material of the film may be selected, for non-restrictive purposes, from polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, polyarylate, polyvinyl alcohol, polycyclic olefin, polyamide, polyurethane, or polyimide. The film may also have a structure comprising multiple overlapping layers, a multilayer film, or a composite film. The film may have one or more functional treatments, such as an anti-scratch coating, an anti-reflective coating, an anti-fouling coating, or a UV or blue light cut coating. The film may be a multilayer anti-fragmentation film. The film may have microstructures on its surface, such as a structured anti-reflective coating, a Fresnel lens, a microlens, a metasurface, or a holographic mirror such as an embossed hologram.

[0053] The polymer wafer 18 may be a plano wafer, also known as an uncorrected wafer. Alternatively, the polymer wafer 18 may have specific optical properties, including a refractive function that may include spherical refractive power, cylindrical refractive power, cylindrical axis, addition, bifocal or trifocal, or a progressive plane and / or a prism.

[0054] The optical properties of the polymer wafer 18 may include reflective properties, such as anti-reflective properties. Advantageously, a polymer wafer 18 having anti-reflective properties reflects a small portion of the light, and therefore, a large portion of the light is transmitted through the polymer wafer 18 and the optical lens 2 instead. The reflective properties may differ between the front surface 20 and the rear surface 22 of the polymer wafer 18. In particular, if the optical lens 2 is intended to be attached to sun protection eyewear, it is preferable that the front surface 20 of the polymer wafer 18 has a high reflectivity to reduce some of the light transmitted through the optical lens 2 toward the wearer's eyes. It is also preferable that the rear surface 22 of the polymer wafer 18 has a low reflectivity to avoid reflecting ambient light toward the wearer's eyes.

[0055] The optical properties of the polymer wafer 18 may include, for example, a light-absorbing function that cuts blue light and / or protects against UV light. Blue light is known to cause glare and eye strain. The light-absorbing function may absorb most of the blue light and ultraviolet light to protect the wearer's eyes.

[0056] The optical properties of the polymer wafer 18 may include a specific color. The polymer wafer 18 may be colored. The color may be selected based on the wearer's preference.

[0057] The optical properties of the polymer wafer 18 may include a polarization function. The polymer wafer 18 may transmit only light having a specific polarization direction.

[0058] The optical properties of the polymer wafer 18 may include photochromic properties. The polymer wafer 18 may darken when exposed to a specific type of light of sufficient intensity, such as blue light or ultraviolet light.

[0059] The polymer wafer 18 may have other properties, including scratch resistance, antistatic properties, antifouling properties, antifogging properties, and / or optical lens edge protection properties. The optical lens edge protection properties may include protection of the optical lens 2 against impact, collision, or abrasion. The optical lens edge protection properties may include sealing the edges of the optical lens 2 from external environmental factors such as moisture, solvents, oxygen, etc. Such protection is particularly useful in embodiments in which the electroactive element 14 extends to the edges of the optical lens 2.

[0060] As shown in Figure 3, the polymer wafer 18 may extend over the edge of the optical lens 2 to protect the edge of the optical lens 2. In particular, the polymer wafer 18 may extend over the edge of the mineral glass element 8 to form a compressible buffer region between the mineral glass element 8 and the spectacle frame element of the spectacle frame. A specific intermediate seal may be inserted between the edge of the optical lens 2 and the portion of the polymer wafer 18 extending over the edge.

[0061] The above optical properties or other properties of the polymer wafer 18 may be properties of the base wafer, or properties of the functional layer, if any, or properties of the combination of the base wafer and the functional layer.

[0062] The edges of the polymer wafer may include a bevel 24, which is adapted to allow the attachment of optical lenses to an eyeglass frame, as shown in Figure 4. The bevel may include outward-facing ridges and / or inward-facing cavities.

[0063] In one embodiment, the optical lens 2 may include a second polymer wafer 26 disposed at least in front of the optical lens 2. The second polymer wafer 26 may have any of the features described for the polymer wafer 18 disposed at least on the rear surface 12. The second polymer wafer 26 may have a functional layer different from that of the polymer wafer 18 disposed at least on the rear surface 12.

[0064] The refractive indices of the materials constituting the mineral glass element 8, the adhesive, the polymer wafer 18, and the second polymer wafer 26 are preferably as close as possible to each other in order to avoid reflected light loss at the interface. Alternatively, if the materials have significantly different refractive indices, the dimensions and shape of the interface must be precisely determined. In particular, the widths of the mineral glass element 8, the adhesive, the polymer wafer 18, and the second polymer wafer 26 must be controlled to avoid generating uncompensated diopters. Furthermore, it is important to avoid surface irregularities that could result in optical deformations that are difficult to compensate for.

[0065] The invention also relates to an optical instrument 28 comprising a pair of optical lenses 2 according to the invention, mounted on an eyeglass frame, as shown in Figure 5.

[0066] The invention has been described above using embodiments without being limited by the broad concept of invention.

[0067] Many further improvements and modifications are given merely as examples and are not intended to limit the scope of the invention, but rather to evoke those skilled in the art when referring to the aforementioned exemplary embodiments, which are determined solely by the appended claims.

[0068] In the claims, the word “equipped with” does not exclude other components or steps, and the indefinite article “a” or “an” does not exclude plurals. The mere fact that different features are described in different dependent claims does not imply that combinations of these features cannot be used to the advantage. No reference numeral in the claims should be construed as limiting the scope of the invention.

Claims

1. 1. An optical lens intended to be placed in front of a wearer's eye, the optical lens having a front surface and a rear surface, the rear surface being the surface intended to be closest to the wearer's eye when the optical lens is placed in front of the wearer's eye, the optical lens having a mineral glass element on the front surface, and further comprising eye protection configured to prevent any fragments of the mineral glass element from reaching the wearer's eye in the event of breakage of the element, the eye protection comprising a polymer wafer placed on at least the rear surface.

2. The optical lens of claim 1 , wherein the polymer wafer is a plano wafer.

3. 3. The optical lens according to claim 1, wherein the polymer wafer has an average thickness of 10 μm or more and 2 mm or less.

4. 4. The optical lens of claim 1, wherein the polymer wafer has a front surface and a rear surface, the rear surface corresponding to the rear surface of the optical lens, and the front surface being bonded to the mineral glass element.

5. 5. The optical lens according to claim 1, wherein the polymer wafer is made of a transparent material such as a thermoplastic or thermosetting material, for example a transparent material suitable for ophthalmic lenses.

6. 6. The optical lens according to claim 1, wherein the polymer wafer has, for example, anti-reflection properties and / or a light absorbing function, a reflective function, for example blue cut and / or UV protection, and / or the polymer wafer has a particular color.

7. 7. The optical lens of claim 1, further comprising at least a second polymer wafer disposed on the front surface of the optical lens.

8. 8. The optical lens according to claim 1, wherein the polymer wafer has a polarizing function.

9. 9. The optical lens according to claim 1, wherein the polymer wafer has photochromic properties.

10. 10. The optical lens of claim 1, wherein the polymer wafer extends over the edge of the optical lens to protect the edge.

11. 11. The optical lens of claim 1, wherein the polymer wafer edge comprises a bevel adapted to allow mounting of the optical lens in an eyeglass frame.

12. 12. Optical lens according to any one of claims 1 to 11, wherein the mineral glass element comprises at least one electro-active element, such as an electrochromic cell and / or a liquid crystal cell and / or a waveguide and / or a holographic mirror.

13. 13. The optical lens of claim 1, wherein the mineral glass element is configured to at least partially break when a steel ball drop test is applied to the lens.

14. 14. Optical lens according to any one of claims 1 to 13, wherein the mineral glass element has a refractive function that is adapted, for example, to a prescription of a wearer.

15. 15. Optical device comprising a pair of optical lenses according to any one of claims 1 to 14 mounted in a spectacle frame.

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