Lens element

Abstract

The invention relates to a lens element (10), in particular for a spectacle lens, a contact lens or an intraocular lens, intended to be worn by a wearer, comprising:-at least a first zone (12) having a dioptric region having a front face and a rear face, the dioptric region having a refractive power based on a prescription of the wearer's eyes; -at least one microstructured second zone (13) outside said first zone (12) and configured for myopia or hyperopia control, said microstructured second zone (13) being characterized by a measurable surface spatial power spectral density PSDmeasure (f) such that, within a spatial frequency range between 0.3 mm-1 and 10 mm-1, formula (I), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula (II), formula PSDnom is a nominal function defined by a Hann window, and f is spatial frequency. # imgabs0 #

Description

Technical Field

[0001] The present disclosure relates to a lens element intended to be worn in front of a person's eye in order in particular to inhibit, reduce or control the development of ametropia of the eye, such as myopia or hyperopia. The lens element is in particular an ophthalmic article.

[0002] The term "ophthalmic article" is particularly understood to mean corrective or other lenses which can be used, for example, as spectacle lenses for spectacles, in particular sunglasses, goggles, shields etc., or contact lenses to be worn by the user in direct contact with his eye. Background Art

[0003] Myopia is characterized by the eye focusing distant objects in front of its retina. Hyperopia is characterized by the eye focusing distant objects behind its retina. Myopia is usually corrected using concave lenses, and hyperopia is usually corrected using convex lenses.

[0004] It has been observed that some individuals, especially children, have inaccurate focus in the peripheral part of the retina when they observe objects at a distance (i.e., under distance vision conditions) when corrected with conventional single vision optical lenses. This is especially true in the case of today's children who have access to and use smartphones in their early childhood. Because of this focus defect in myopic children who are corrected for distance vision, images of nearby objects are also formed behind their retina (even in the foveal area).

[0005] This focusing defect may have an impact on the progression of myopia in such individuals. It can be observed that for most of these individuals, the myopia defect tends to worsen over time.

[0006] Foveal vision corresponds to the observation condition in which the image of the viewed object is formed by the eye in a central area of ​​the retina known as the fovea.

[0007] Peripheral vision corresponds to the perception of scene elements that are laterally offset with respect to the viewed objects, the images of which are formed on the peripheral parts of the retina, away from the fovea.

[0008] The ophthalmic correction provided to a subject with refractive errors is usually adapted to his foveal vision. However, it is well known that the correction for peripheral vision must be reduced relative to the correction determined for foveal vision. In particular, studies have been conducted showing that focusing light far behind the retinal periphery causes the eye to elongate and thus causes myopic defects to worsen, even when the light is perfectly focused on the fovea.

[0009] Therefore, there appears to be a need for a lens element that is able to inhibit, control or at least slow the progression of refractive errors of the eye, such as myopia or hyperopia.

[0010] WO 2019206569 in the name of the applicant proposes a solution by disclosing a lens element having optical elements which in particular show a focus shift which makes it possible not to focus the image on the periphery of the retina of the eye under standard wearing conditions.

[0011] The present disclosure is directed to providing lens elements having improved myopia or hyperopia control properties. Summary of the invention

[0012] To achieve this object, the present disclosure proposes a lens element, in particular for a spectacle lens, a contact lens or an intraocular lens, intended to be worn by a wearer, the lens element comprising:

[0013] - at least a first zone having a refractive zone with a front face and a rear face, the refractive zone having a refractive power based on the eye prescription of the wearer;

[0014] - at least one microstructured second zone, the at least one microstructured second zone being outside the first zone and configured for myopia or hyperopia control, the microstructured second zone being characterized by a measurable surface spatial power spectral density PSD measured (f) so that in the spatial frequency range between 0.3 mm-1 and 10 mm-1

[0015]

[0016] PSD nom is the nominal function defined by the Hann window

[0017]

[0018] Where f is the spatial frequency.

[0019] It has been observed that a measurable surface spatial power spectral density within a specific spatial frequency range is a good marker for a lens element having improved myopia or hyperopia control efficiency.

[0020] According to further aspects relating to the lens element defined above or the method defined above, taken alone or in combination:

[0021] In the microstructured second zone, the measured surface spatial power spectral density PSD measured At 0.3mm -1 With 10mm -1 Between, especially 0.3mm -1 With 5mm -1 The spatial frequency range between equal to or above the nominal PSD nom function.

[0022] Measured surface spatial power spectral density PSD measured (f) At least one local maximum may be shown on a logarithmic scale.

[0023] At least one local maximum is located at 0.3 mm -1 Up to 2mm -1 The spatial frequency range between (including the boundary values).

[0024] There may also be at least two local maxima located at 1 mm -1 Up to 5mm -1 The spatial frequency range between (including the boundary values).

[0025] The microstructured second zone may include at least one optical element that locally modifies the optical power relative to a refractive zone having an optical power based on an eye prescription of the wearer.

[0026] The at least one optical element locally modifying the optical power is for example selected from the group comprising: refractive or diffractive lenslets, monofocal lenslets, bifocal lenslets, multifocal lenslets, toric lenslets, Pi-Fresnel lenslets.

[0027] The microstructured second zone comprises in particular a number of optical elements which locally modify the optical power and are arranged according to a predetermined pattern.

[0028] The predetermined pattern may be a ring pattern, in particular a ring pattern along several concentric rings, or for example a hexagonal pattern.

[0029] The at least one optical element that locally modifies the optical power is arranged on the front face or on the rear face.

[0030] According to another aspect, at least one optical element locally modifying the optical power is embedded in a layer of said lens element.

[0031] The surface of the at least one microstructured second zone can be at least 10 mm2.

[0032] The at least one microstructured second zone is, for example, located outside the central zone of the lens element.

[0033] The microstructured second zone may extend radially from the optical center of the lens element.

[0034] The invention also relates to spectacles provided with a lens element as defined above. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other advantages and features will become apparent after reading the following description of the accompanying drawings, in which:

[0036] - Figure 1 is a schematic plan view of a lens element for explaining the principle of a lens element configured for myopia / hyperopia control;

[0037] - Figure 2 yes Figure 1 A generalized cross-sectional view of a lens element,

[0038] - Figure 3 partially shows a microstructured second zone with optical elements according to a first example,

[0039] - Figure 4 The log-log graph shows the Figure 3 An example of measured and nominal surface spatial power spectral density over a specific spatial frequency range,

[0040] - Figure 5 partially shows a microstructured second zone with optical elements according to a second example,

[0041] - Figure 6 The log-log graph shows the Figure 5 Examples of measured and nominal surface spatial power spectral density over a specific spatial frequency range. DETAILED DESCRIPTION

[0042] In all the drawings, the same elements are provided with the same reference numerals.

[0043] The following embodiments are merely examples. Although this specification relates to one or several embodiments, the present invention is not limited to these embodiments. In addition, features described in connection with one embodiment may also be related to another embodiment, even if this is not explicitly mentioned. Simple features of different embodiments may also be combined to provide additional implementations.

[0044] In this specification, by the "front" or "back" face of a layer or lens element or surface, reference is made to the propagation of light rays through the ophthalmic lens toward the eye when the ophthalmic device carrying the ophthalmic lens is worn on the wearer's face. Thus, the "front" face is always the face farthest from the user's eye, and therefore closest to the field of vision, while the "back" face is always the face closest to the user's eye.

[0045] The present disclosure relates to a lens element intended to be worn in front of a wearer's eye.

[0046] In the context of the present disclosure, the term "lens element" may refer to a lens blank, an uncut optical lens, a spectacle optical lens that is edged to fit a specific spectacle frame, an ophthalmic lens or a contact lens.

[0047] In the context of the present disclosure, a microstructured area is considered to be an area that provides an optical wavefront modification, in particular in terms of its intensity, curvature or light deflection. These wavefront modifications can be achieved by different physical phenomena (interaction of light and matter), such as refraction, diffraction, absorption (partial or total), scattering, etc.

[0048] The microstructured area can be located on top of the substrate, in particular on the front side, but also on the back side. The microstructured area can also be embedded in such a substrate. For example, when the substrate comprises several layers, the microstructured area can be part of a specific optical layer.

[0049] The hard coating protects the lens elements and covers the microstructured areas as well as the refractive areas.

[0050] As mentioned above, the function of the microstructured area can be based on an absorption principle (locally up to 100%) or not based on an absorption principle.

[0051] Alternatively, the function of the microstructured area can also be based on the principles of scattering or light diffraction.

[0052] like Figure 1 and Figure 2 As shown, a lens element 10 according to the present disclosure comprises:

[0053] - at least a first zone 12 having a refractive area, and

[0054] at least one microstructured second zone 13 configured for myopia or hyperopia control and located outside said first zone 12 .

[0055] The microstructured second zone 13 may present, for example, a plurality of optical elements 14 which are, for example, located on the front face F1 of the lens element 10 and which may be partially overlapping or non-overlapping.

[0056] In the present context, the optical element 14 may be regarded as an optical microstructure having a certain physical extension Z (deformation / height) and a physical extension X / Y (width / length / diameter).

[0057] However, the microstructured region 13 can also be realized in another way, which does not have individual optical elements 14 but has, for example, local refractive index variations, local absorption variations or local scatterers.

[0058] In these Figure 1 and Figure 2 In , the lens element 10 comprises a substrate 16 and the first zone 12 with the refractive area together with the microstructured second zone 13 with the optical elements 14 form the front face F1 of the lens element 10 which is the interface with the surrounding air.

[0059] In other embodiments, for example when the substrate comprises several layers, the microstructured second regions 13 can be embedded in a layer of the multilayer substrate. The microstructured second regions 13 can be part of a specific optical layer of the substrate 16.

[0060] The substrate 16 is for example made of a plastic material, for example a polymer substrate, such as a thermosetting material, in particular poly(urea-urethane), or a thermoplastic material, in particular polyamide (PA), such as nylon or polycarbonate or polyester.

[0061] The microstructured second region 13 , in particular the optical element 14 , can be made of the same material as the substrate 16 and therefore have the same refractive index.

[0062] In other examples, particularly when embedded, the microstructured region 13 can be made of a different material having a different refractive index than the refractive material forming the substrate 16 .

[0063] The optical element 14 of the second zone may locally modify the optical power relative to the first zone 12 having a refractive zone with an optical power based on the eye prescription of the wearer.

[0064] The at least one optical element 14 locally modifying the optical power is selected from the group comprising: a refractive or diffractive lenslet, a monofocal lenslet, a bifocal lenslet, a multifocal lenslet, a toric lenslet, a Pi-Fresnel lenslet.

[0065] like Figure 1 and Figure 2 As shown, the microstructured second zone 13 comprises several optical elements 14 which locally modify the optical power and are arranged according to a predetermined pattern, such as a ring pattern, in particular along several concentric rings. Other patterns may be chosen, like for example a hexagonal pattern.

[0066] As a possible example, the optical element 14 is Figure 1 and Figure 2 F1 protrudes from the front.

[0067] In other embodiments, the microstructured second regions 13 and the optical elements 14 may be located on the back side R1 of the substrate 16 .

[0068] In other examples, optical element 14 may be formed from a cavity (open or closed), a recess, or a hole.

[0069] The surface of the at least one microstructured second area 13 is at least 10 mm2.

[0070] The first area 12 having the refractive region is preferably formed as an area other than the area formed by the at least one microstructured second area 13. In other words, the refractive region 12 is an area complementary to the area occupied by the microstructured second area 13.

[0071] exist Figure 1 In the present case, the microstructured second zone 13 is bounded, for example, by a dashed outer circle Lo and a dashed inner circle Li. Figure 1 Also shown are two first zones 12, which are a ring-shaped zone 12o and a circular-shaped central portion 12c.

[0072] The first zone 12 with a refractive area (including 12c and 12o) is configured to provide the wearer with a first optical power based on the wearer's prescription under standard wearing conditions, in particular for foveal vision, which is used to correct the refractive error of the wearer's eye. The purpose of the first zone 12 with a refractive area is to focus parallel incident light on the retina.

[0073] The microstructured area 13 is intended to produce unfocused light, for example in front of the retina, especially in the peripheral area, in order to reduce myopia.

[0074] The wearing condition is understood as the position of the lens element 10 relative to the wearer's eye, as defined by the anteversion angle, cornea-to-lens distance, pupil-to-cornea distance, center of rotation of the eye (CRE)-to-pupil distance, CRE-to-lens distance, and wrap angle.

[0075] like Figure 1 As shown, the at least one microstructured second zone 13 is located outside the central region CR of the lens element 10 .

[0076] In some embodiments, Figure 1 As shown, the microstructured second zone 13 extends radially from the optical center 16 of the lens element 10 .

[0077] like Figure 1 and Figure 2 The lens element 10 presented in can be manufactured in various ways, in particular by molding and / or machining and polishing a substrate 16 or lens blank.

[0078] To achieve improved myopia / hyperopia control, the microstructured second zone 13 for myopia or hyperopia control is characterized by a measurable surface spatial power spectral density PSD measured (f) so that in the spatial frequency range between 0.3 mm-1 and 10 mm-1

[0079]

[0080] PSD nomis the nominal function defined by the Hann window

[0081]

[0082] Where f is the spatial frequency.

[0083] The power spectral density PSD indicates the degree of surface or diopter inhomogeneity for a light ray on its path through the lens element 10. It is defined in particular in the standard ISO 10110-8:2017 entitled "Optics and photonics - Preparation of drawings of optical components and systems - Part 8: Surface texture".

[0084] Surface texture is a property related to the profile of an optical surface and can be effectively described using statistical methods.

[0085] More than 30mm -1 In the spatial frequency range, PSD describes the "surface roughness" which is not the concern of the present invention.

[0086] For myopia or hyperopia control, the spatial frequency range of interest is 0.3mm -1 With 10mm -1 between.

[0087] PSD measured (f) is the measured PSD function. This measurement can be performed mechanically or optically. Optical non-contact measurement is particularly preferred when the microstructured second area 13 is embedded.

[0088] This method first requires measuring the surface of the optical lens. This surface measurement can be performed by a tactile surface measuring instrument or a non-contact instrument.

[0089] A surface profiler, a coordinate measuring machine or a non-contact 3D optical profiler or any other known surface measuring device may be used. Depending on the technique used, local or global areas may be measured.

[0090] Some options are available for measuring larger areas, such as rectangular or circular tiles. The goal is to measure the optical element at least over the area of ​​interest.

[0091] The top surface of the optical lens or the surface below the coating(s) can be measured, or even an optical element encapsulated between the front and back surfaces of the optical lens can be measured. For example, interferometry can be used to measure the surface of the optical element. In this case, the refractive index of the coating(s) should be known to compensate for the height and infer the true surface from it.

[0092] The second optional step of the method is to remove the shape of the first zone 12 with a refractive area of ​​the optical lens 10. The shape of the first zone 12 with a refractive area can be removed before any other metrological operation. However, since the spatial frequency of the shape of the first zone 12 with a refractive area is outside the range of the spatial frequency of the microstructured second zone 13, this second step can be considered optional and is not performed at 0.3 mm. -1 With 10mm -1 The spatial frequency range between them has limited impact on the PSD function.

[0093] This second step can be performed using any known standard solution for analyzing profilometry and topographic data.The shape of the first zone 12 with the refractive zone is typically a rotational shape (cylindrical, spherical) corresponding to the prescription of the wearer's eye.

[0094] Before calculating the surface condition parameters, the metrologist performs adjustments or shape removal. This operation involves modeling a shape and associating it with the measured points, then subtracting the shape and obtaining a flat or nearly flat surface.

[0095] This is Figure 3 , which partially shows a microstructured second zone 13 with optical elements 14 .

[0096] In some cases it may be useful to remove the natural shape by spherical equations, by complex polynomial equations, by filtering, or by complex algorithms using Zernike polynomials.

[0097] When the basis radius is unknown, it can be calculated by the method of least squares. A standard approach in regression analysis is to approximate the solution of an overdetermined system by minimizing the sum of the squares of the residuals obtained in the solution of each equation.

[0098] The same approach can be used with polynomials involving powers higher than 3. An alternative approach is to define the fitting surface based on a classical subset of orthogonal Zernike polynomials.

[0099] Several statistical parameters can be used as indicators to determine the best method or the best approximation order: RMS root mean square, average roughness, and area flatness deviation.

[0100] Measuring the microstructured second areas 13 across the entire surface of the optical lens 10 can be complicated with currently available measurement equipment.

[0101] The present disclosure further relates to a method of measuring the entire surface of an optical lens using a currently available optical profiler.

[0102] An optical profiler (eg, an interferometer) is capable of measuring the shape, waviness, and roughness of the surface of an optical lens, particularly an optical element, by using a technique that uses interference of superimposed waves to extract height information (x, y, z data).

[0103] Combining an X,Y motorized stage and a stitching process, it is possible to extend the measurement range to be larger than the field of view of the initial objective. Most measurement setups use the x,y position of each frame to calculate the final stitching, as the accuracy is better than using common data from each frame. Finally, all structures of an optical component can be measured, such as Figure 1 A ring of optical element 14 is represented.

[0104] This method can also be used to measure packaged optical components, that is, optical components included between the front and back surfaces of an optical lens, or under a coating.

[0105] Figure 4 This is shown in a log-log plot:

[0106] -PSD nom , a nominal function defined by a Hann window, referenced 100, and

[0107] -PSD measured (f) For example Figure 3 An example measured surface spatial power spectral density of the microstructured second region 13 is shown, which is referenced 102 .

[0108] Figure 3 Line 104 in corresponds to the tangential slice where the calculations are performed.

[0109] for Figure 3 and Figure 4 The outline of

[0110]

[0111] Even if other cross-sectional lines are taken along which the calculation is performed (for example, a cross-sectional line passing through two optical elements 14), the relationship is verified. Established.

[0112] It has been shown that lens elements having such microstructured second zones 13 are very efficient for myopia or hyperopia control.

[0113] As in Figure 4 It can also be seen that in the microstructured second area 13, the measured surface spatial power spectral density PSD measured At 0.3mm -1 With 10mm -1 Between, especially 0.3mm -1 With 5mm-1 The spatial frequency range between equal to or above the nominal PSD nom function.

[0114] In addition, the measured surface spatial power spectral density PSD measured (f) shows at least one local maximum, referenced 106, on a logarithmic scale.

[0115] At least one local maximum 106 is located at 0.3 mm -1 Up to 2mm -1 In the spatial frequency range between (including the boundary values), especially at 0.9mm -1 Place.

[0116] As in Figure 4 As can be seen in FIG. 1 , the second local maximum 108 is located at 1.8 mm. -1 Place.

[0117] Therefore, at least two local maxima 106 and 108 are located at 1 mm -1 Up to 5mm -1 The spatial frequency range between (including the boundary values).

[0118] These local maxima 106 and 108 are of considerable importance, since they can be regarded as “signatures” of the microstructured second regions 13 .

[0119] The higher the local maximum, in particular the first local maximum 106, the stronger the periodic arrangement of the microstructured second zones 13 with the optical elements 14 or the wavefront shaping variation, which enhances the myopia / hyperopia control.

[0120] Figure 5 is similar to Figure 3 , and partially shows a microstructured second zone 13 with optical elements 14 of another embodiment, wherein the optical elements 14 are arranged according to a hexagonal pattern.

[0121] Figure 6 Similar to Figure 4 and is shown in a log-log graph. Figure 5 Microstructured second zone 13:

[0122] -PSD nom , a nominal function defined by a Hann window, referenced 100, and

[0123] -PSD measured (f) For example Figure 5 An example measured surface spatial power spectral density of the microstructured second region 13 is shown, which is referenced 102 .

[0124] for Figure 5 and Figure 6 The outline of

[0125]

[0126] In this case, there are -1 and 3.4mm -1 There are two local maxima 106 and 108 at .

[0127] The present disclosure has been described above by means of embodiments without limiting the general inventive concept. Many further modifications and variations will be apparent to those skilled in the art upon reference to the foregoing illustrative embodiments, which are given by way of example only and are not intended to limit the scope of the present disclosure, which is determined solely by the appended claims.

[0128] In the claims, the word "comprising" does not exclude other elements or steps and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that different features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage. Any reference signs in the claims shall not be construed as limiting the scope of the disclosure.

Claims

1. A lens element (10), in particular for a spectacle lens, a contact lens or an intraocular lens, intended to be worn by a wearer, comprising: - at least a first zone (12) having a refractive zone with a front face (F1) and a rear face (R1), said refractive zone having a refractive power based on the eye prescription of the wearer; - at least one microstructured second zone (13) outside the first zone (12) and configured for myopia or hyperopia control, the microstructured second zone (13) being characterized by a measurable surface spatial power spectral density PSD measured (f) so that in the spatial frequency range between 0.3 mm-1 and 10 mm-1 PSD nom is the nominal function defined by the Hann window Wherein, f is the spatial frequency.

2. A lens element according to claim 1, wherein In the microstructured second zone (13), the measured surface spatial power spectral density PSD measured At 0.3mm -1 With 10mm -1 Between, especially 0.3mm -1 With 5mm -1 The spatial frequency range between equal to or above the nominal PSD nom function.

3. A lens element according to claim 1 or 2, wherein: The measured surface spatial power spectral density PSD measured (f) At least one local maximum is shown on a logarithmic scale.

4. A lens element according to any one of claims 1 to 3, wherein At least one local maximum (106) is located at 0.3 mm -1 Up to 2mm -1 The spatial frequency range between and including the boundary values.

5. A lens element according to any one of claims 1 to 4, wherein At least two local maxima (106, 108) are located at 1 mm -1 Up to 5mm -1 The spatial frequency range between and including the boundary values.

6. A lens element according to any one of claims 1 to 5, wherein: The microstructured second zone (13) comprises at least one optical element (14) which locally modifies the optical power relative to the refractive zone, the refractive zone having an optical power based on an eye prescription of the wearer.

7. A lens element according to claim 6, wherein: The at least one optical element (14) locally modifying the optical power is selected from the group consisting of: refractive or diffractive lenslets, monofocal lenslets, bifocal lenslets, multifocal lenslets, toric lenslets, Pi-Fresnel lenslets.

8. A lens element according to claim 6 or 7, wherein: The microstructured second zone (13) comprises a plurality of optical elements (14) which locally modify the optical power and are arranged according to a predetermined pattern.

9. A lens element according to claim 8, wherein: The predetermined pattern is a ring pattern, in particular a ring pattern along several concentric rings.

10. A lens element according to claim 8, wherein: The predetermined pattern is a hexagonal pattern.

11. A lens element according to any one of claims 6 to 10, wherein The at least one optical element (14) that locally modifies the optical power is arranged on the front face (F1) or the rear face (R1).

12. A lens element according to any one of claims 6 to 10, wherein The at least one optical element (14) which locally modifies the optical power is embedded in a layer of the lens element (10).

13. A lens element according to any preceding claim, wherein: The surface of the at least one microstructured second area (13) is at least 10 mm2.

14. A lens element according to any preceding claim, wherein: The at least one microstructured second zone (13) is located outside the central zone (CR) of the lens element (10).

15. A lens element according to any preceding claim, wherein: The microstructured second zone (13) extends radially from the optical center (16) of the lens element (10).

Images