Parabolic lens and eyewear comprising such lens

Abstract

The invention describes a lens (1) for eyeglasses and / or masks, having an inner surface (3) tending to point to at least one eye of a wearer and an outer surface (5) opposite the inner surface (3); a first inner center curve (30) and a second inner center curve (31) are defined on the inner surface (3); a first outer center curve (50) and a second outer center curve (51) are defined on the outer surface (5); the first inner center curve (30) and the first outer center curve (50) are respectively defined by the intersection of the inner surface (3) and the outer surface (5) with a first plane (X0) passing through the geometric center of the lens (1) and extending in a substantially vertical direction; the second inner center curve (31) and the second outer center curve (51) are respectively defined by the intersection of the inner surface (3) and the outer surface (5) with a second plane (Y0) passing through the geometric center of the lens (1); the second plane (Y0) is inclined at an angle between-25 DEG and 25 DEG with respect to the horizontal; the inner surface (3) is convex towards the eyes of the wearer at least along a first inner center curve (30) and concave at least along a second inner center curve (31); the outer surface (5) is convex towards the eyes of the wearer at least along a first outer central curve (50) and concave at least along a second outer central curve (51).

Description

[0001] The invention relates to a parabolic lens, an eyewear comprising such a lens and a method for designing and / or manufacturing such a lens. The invention is applicable to the field of spectacles, in particular protective spectacles and / or face masks, but also to ophthalmic spectacles and / or face masks.

[0002] The invention is usefully used in the manufacture of sunglasses and / or face masks.

[0003] The present invention is also useful in the manufacture of corrective or ophthalmic spectacles and / or face masks.

[0004] Known spectacles and / or face masks with lenses, these lenses have an inner surface tending to point towards the wearer's eyes and an opposite surface pointing towards the outside. In known spectacles and / or face masks, the outer surface of the lens is a convex surface, and the inner surface is a concave surface.

[0005] This specific configuration of the surface of the lens limits the shapes that the lens can take and accordingly limits the freedom to give the lens itself specific and unexpected aesthetic effects. At present, indeed, the imparting of aesthetic effects is only possible with the shape of the lens (i.e. the shape of the cut) and its possible coloring.

[0006] Furthermore, it is disadvantageous that lenses made in this way adapt poorly to some facial shapes.

[0007] The object underlying the present invention is to provide a lens, an eyewear comprising such a lens and a method for designing and / or producing such a lens which overcome the above-mentioned disadvantages of the known art.

[0008] A particular object of the present invention is to provide a lens that can be given a desired aesthetic shape that differs from the aesthetic shapes of lenses of known types.

[0009] It is a further object of the present invention to provide a lens that is particularly well suited to conform to certain face types.

[0010] It is an additional object of the present invention to provide a lens in which the optical aberrations are minimized, or with a desired optical power, and in which the resolution characteristics of the lens itself are better.

[0011] Another object of the present invention is to provide a lens that meets the requirements set forth by current regulations in the field of eyewear.

[0012] The above tasks and the above objects and other objects which will become more apparent below are achieved by a lens as claimed in claim 1, wherein the lens has an inner surface tending to point toward the wearer's eye and an outer surface opposite to the inner surface; the inner surface and the outer surface are spaced apart from each other so as to define a thickness;

[0013] A first inner center curve and a second inner center curve are defined on the inner surface of the lens; a first outer center curve and a second outer center curve are defined on the outer surface of the lens;

[0014] The first inner center curve and the first outer center curve are defined by intersections of the inner surface and the outer surface, respectively, with a first plane passing through a geometric center of the lens and extending in a substantially vertical direction;

[0015] The second inner center curve and the second outer center curve are defined by intersections of the inner surface and the outer surface with a second plane passing through the geometric center of the lens, respectively; the second plane is inclined at an angle between -25° and 25° relative to the horizontal direction;

[0016] It is characterized in that

[0017] said inner surface being convex toward an eye of a wearer at least along said first inner central curve and concave at least along said second inner central curve;

[0018] Towards the wearer's eye, the outer surface is convex at least along the first outer central curve and concave at least along the second outer central curve.

[0019] Preferably, the second plane extends in a substantially horizontal direction.

[0020] The invention also relates to an eyewear as claimed in claims 14 and 15.

[0021] Further features are provided in the dependent claims.

[0022] Further features and advantages will become more apparent from the description of preferred but not exclusive embodiments of lenses, eyewear and methods for designing and / or manufacturing such lenses, illustrated in an indicative and non-limiting manner with the aid of the accompanying drawings, in which:

[0023] - Figure 1 and Figure 2 A pair of spectacles comprising a pair of lenses according to the invention is shown;

[0024] - Figure 2a and Figure 2b Two different views of a pair of lenses according to the present invention are shown;

[0025] - Figure 3 shows a plan view of a semi-finished lens before it is shaped to form a lens according to the invention, wherein the section plane XX passes through the axis of rotation of the torus generating the outer surface of the semi-finished lens, and the section plane YY is orthogonal to the axis of the torus;

[0026] - Figure 4Shown in top view Figure 3 semi-finished products;

[0027] - Figure 5 Shown in side view Figure 3 and Figure 4 A semi-finished product, some of which have section planes YY perpendicular to section plane XX;

[0028] - Figure 6 Shown in different side views Figures 3 to 5 A semi-finished product in which some of the section planes XX pass through the axis of rotation of the torus generating the outer surface of the semi-finished lens;

[0029] - Figure 7 Shown along Figure 5 The plane YY depicted in Figure 5 semi-finished products;

[0030] - Figure 8 Shown along Figure 6 The plane XX described in Figure 6 semi-finished products;

[0031] - Fig. 9 Schematically illustrates a comparison between a reference grid representing an ideal case of a lens (ie without aberrations) and a grid associated with a lens according to the invention;

[0032] - Figures 10 to 12 Different perspective views of a lens for a mask according to the invention are shown.

[0033] With reference to the accompanying drawings, a lens 1 for spectacles and / or a mask is described below.

[0034] exist Figures 3 to 8 In particular, a semi-finished lens 10 is shown, i.e. a round wafer from which the lens 1 is then formed by a cutting process known as "forming". However, what is shown with reference to the semi-finished product 10 applies to the lens 1, since the properties of the lens 1, such as the optical and geometrical features, are already present in the semi-finished product 10, which is then shaped to manufacture the lens 1.

[0035] The lens 1 according to the invention has an inner surface 3 which is intended to be directed towards at least one eye of the wearer.

[0036] In particular, in the present disclosure, the term wearer refers to a person who wears a pair of glasses comprising two different lenses according to the present invention or a mask having a single lens according to the present invention.

[0037] Eyewear comprising at least one lens 1 as described in the present disclosure also forms part of the present invention.In the present disclosure, the term eyewear refers to any kind of spectacles or masks.

[0038] Indeed, spectacles 100 comprising at least one lens 1 , preferably two lenses 1 as described in the present disclosure also form part of the present invention.

[0039] A mask comprising a single lens 1 as described in this disclosure also forms part of the present invention.

[0040] According to a first preferred embodiment, the eyewear is sunglasses and / or a sun shield, and therefore the lens 1 is preferably a sun lens.

[0041] According to a second preferred embodiment, the eyewear is a corrective spectacles and / or a corrective face mask, and therefore the lens 1 is preferably a corrective or ophthalmic lens.

[0042] The lens 1 is suitable for frames and / or visors of all types of spectacles 100 , whether they are made of cellulose acetate, injection-moulded, metal and / or “rimless”.

[0043] Therefore, the lens 1 is preferably a lens of a thermoplastic material or acrylic polymer, such as for example polyamide and / or biopolyamide. Alternatively, the lens 1 is made of polycarbonate.

[0044] The lens 1 further has an outer surface 5 opposite the inner surface 3 .

[0045] Preferably, the outer surface 5 is cylindrical.

[0046] The inner surface 3 and the outer surface 5 are spaced apart from each other, thereby defining a lens thickness S. The lens thickness S is typically between 0.8 mm and 5 mm. Preferably, the lens thickness S is 2 mm.

[0047] In a preferred embodiment, the lens 1 is a shading lens. Shading can be added to lenses for glasses and / or masks, on the one hand to improve their aesthetics, and on the other hand to attenuate the intensity of light transmitted to the wearer's eyes, for example. Alternatively, the lens 1 is a tinted lens. The shading or tinting can be in any mode or "pattern", such as but not limited to classic gradient shading, circular shading, overlapping shading, transparent shading or shaped shading.

[0048] The lens 1 can be of polar type and of non-polar type. In a polar embodiment, the lens 1 is functionalized, for example comprising a polarizing layer and / or a photochromic layer and / or a layer with contrast enhancing properties.

[0049] A variety of treatments may be applied to the lens 1, such as, but not limited to, anti-reflection, mirror treatment, anti-fog treatment, hydrophobic treatment and / or anti-fouling treatment, anti-scratch treatment, anti-static treatment, and other treatments known in the art. The treatments may be applied to the outer surface 5 and / or the inner surface 3 of the lens 1.

[0050] The lens 1 may comprise a two-dimensional and / or three-dimensional pattern. Furthermore, a finishing treatment may be applied to the lens 1. For example, a surface pattern obtained by laser machining or pad printing or other techniques known in the art may be applied to the lens 1.

[0051] Furthermore, decorations by UV / laser printing and / or pad printing and / or engraving may be applied to the lens 1 and / or two-dimensional elements may be inserted into the lens 1 that are visible or invisible to anyone observing the lens 1 from the outside, such as a two-dimensional insert containing electronic devices for decorative and / or functional purposes (e.g., an RFID tag).

[0052] The lens 1 can be manufactured by injection molding, casting or thermoforming.

[0053] A first inner central curve 30 and a second inner central curve 31 are defined on the inner surface 3 of the lens 1 .

[0054] In addition, a first outer central curve 50 and a second outer central curve 51 are defined on the outer surface 5 of the lens 1 .

[0055] In particular, the first inner center curve 30 and the first outer center curve 50 are defined by the intersection of the inner surface 3 and the outer surface 5 with the first plane X_0, respectively. This first plane X_0 passes through the geometric center of the lens 1 and extends in a substantially vertical direction. In the present disclosure, the terms vertical and horizontal are intended to be relative to one or more lenses installed in the frame or mask of the glasses and relative to the wearer. In the case of a toric lens 1, this first plane X_0 further passes through the axis of rotation of the torus that generates the outer surface 5. In the case of lenses 1 of other shapes, the first plane X_0 is a substantially vertical plane that still passes through the geometric center of the lens 1.

[0056] On the other hand, the second inner center curve 31 and the second outer center curve 51 are defined by the intersection lines of the inner surface 3 and the outer surface 5 with the second plane Y_0, respectively. This second plane Y_0 passes through the geometric center of the lens 1. This second plane Y_0 is inclined at an angle between -25° and +25° relative to the horizontal plane.

[0057] It should be noted that the second plane Y_0 may also be inclined at an angle equal to 0 relative to the horizontal plane, that is, the second plane may be substantially parallel to the horizontal plane.

[0058] Preferably, the second plane extends in a substantially horizontal direction. In the case of a toric lens, the second plane Y_0 is parallel to a plane defined as a plane orthogonal to the axis of rotation of the torus and passing through the center of the circumference of the generating torus.

[0059] According to an embodiment, in the case of a toric lens 1, such second plane Y_0 is preferably inclined at a first angle α between -25° and +25° relative to a horizontal plane, which is called the anteversion angle. In other words, once the plane that divides the toric plane horizontally into two parts is defined as a horizontal plane, the second plane Y_0 is a plane inclined at such a first angle α relative to the horizontal plane.

[0060] According to the example shown, α is between −4° and −5° and is in particular equal to −4.625°.

[0061] According to a first preferred embodiment, for any type of lens 1, the first plane X_0 is preferably inclined at a second angle β between -30° and +30° relative to the vertical plane, which is called the wrap angle. In other words, once the plane that vertically divides the lens 1 into two parts is defined as a vertical plane, the first plane X_0 is a plane inclined at this second angle β relative to the vertical plane.

[0062] Preferably, β is between 5° and 7°.

[0063] According to the present invention, reference Figure 2a and Figure 2b It should be noted that, relative to the wearer's eye, the inner surface 3 is convex at least along the first inner center curve 30. The inner surface 3 is further concave at least along the second inner center curve 31 relative to the wearer's eye.

[0064] Still reference Figure 2a and Figure 2b On the other hand, the outer surface 5 is convex at least along a first outer central curve 50 and concave at least along a second outer central curve 51 relative to the wearer's eye.

[0065] In other words, for a person looking at the lens from the outside, the lens 1 is concave in a substantially vertical direction and convex in a direction inclined at an angle between -25° and 25° with respect to the horizontal.

[0066] This "vertical" outward concavity effect is aesthetically perceptible to a person looking at the lens 1 as worn by the wearer, e.g. Figure 2 and Figure 2a exemplified in .

[0067] Advantageously, lens 1 thus has a parabolic shape.

[0068] According to the present invention, preferably, the inner surface 3 has a curvature radius R30 that changes continuously in an increasing and / or decreasing manner at least along the first inner center curve 30 .

[0069] In particular, the radius of curvature R30 varies continuously, which means that the inner surface 3 has no discontinuities (eg, steps) along the first inner center curve 30 .

[0070] Furthermore, the radius of curvature R30 varies in increasing or decreasing manner, or in increasing and decreasing manner, in different portions of the inner surface 3 along the first inner center curve 30. In other words, the radius of curvature R30 is not a constant radius throughout the first inner center curve 30.

[0071] Similarly, even preferably, the inner surface 3 further has a radius of curvature R31 that varies continuously in an increasing and / or decreasing manner at least along the second inner center curve 31 .

[0072] In particular, the radius of curvature R31 varies continuously, which means that the inner surface 3 has no discontinuity (eg, step) along the second inner center curve 31 .

[0073] Furthermore, the radius of curvature R30 varies in increasing or decreasing manner, or in increasing and decreasing manner, in different portions of the inner surface 3 along the second inner center curve 31. In other words, the radius of curvature R30 is not a constant radius throughout the second inner center curve 31.

[0074] Preferably, the radius of curvature R30 of the inner surface 3 at least partially increases and at least partially decreases along the first inner center curve 30 .

[0075] Still preferably, the radius of curvature R31 of the inner surface 3 at least partially increases and at least partially decreases along the second inner center curve 31 .

[0076] Preferably, a radius of curvature R30 of the inner surface 3 along the first inner center curve 30 is different from a radius of curvature R31 of the inner surface 3 along the second inner center curve 31 .

[0077] In other words, preferably, the radius of curvature varies within the inner surface 3 .

[0078] Still preferably, the outer surface 5 has a constant radius of curvature R50 at least along the first outer center curve 50 .

[0079] Preferably, the outer surface 5 has a constant curvature radius R51 at least along the second outer center curve 51 .

[0080] Preferably, a radius of curvature R50 along the first outer center curve 50 and a radius of curvature R51 along the second outer center curve 51 are different from each other.

[0081] For example, in the specific embodiment shown in the drawings, the radius of curvature R50 along the first outer center curve is about 130.5 mm, and the radius of curvature R51 along the second outer center curve 51 is about 261 mm.

[0082] More preferably, the thickness S of the lens 1 varies continuously.

[0083] In particular, the thickness S varies with the curvature radius R30, R31 of the inner surface 3 because the curvature radius R30, R31 of the inner surface 3 varies along the first inner center curve 30 or along the second inner center curve 31, while the curvature radius R50, R51 of the outer surface 5 is constant along the corresponding first outer curve R50 and second outer curve R51.

[0084] According to a preferred embodiment, the inner surface 3 has further radii of curvature R32, R34, R36, R38, R40, R42 along the further first inner curve. Figure 8 As can be seen in FIG. 3 , these additional first inner curves are defined by the intersection of the inner surface 3 and additional planes X_-6, X_-4, X_-2, X_2, X_4, X_6 that are angularly spaced apart from the first plane X_0. In particular, each radius of curvature R32, R34, R36, R38, R40, R42 changes continuously in an increasing and / or decreasing manner along the corresponding additional first inner curve.

[0085] Planes X_0, X_2, X_4, X_6, X_-2, X_-4, X_-6 Figure 6 For example, the depicted planes X_0, X_2, X_4, X_6, X_-2, X_-4, X_-6 are angularly spaced 2° from each other.

[0086] Still preferably, the inner surface 3 has a radius of curvature that varies continuously in an increasing and / or decreasing manner along each first inner curve, each first inner curve being defined by the intersection of the inner surface 3 with any radial plane angularly spaced relative to the first plane X_0.

[0087] In other words, on the inner surface 3 , each further first inner curve defined on the inner surface 3 by any plane XX spaced angularly relative to X_0 has a continuously varying non-constant radius of curvature.

[0088] Basically, preferably, not only the further planes X_2, X_4, X_6, X_-2, X_-4, X_-6, but also all planes which are angularly spaced apart relative to the first plane X_0 have a radius of curvature which varies continuously in an increasing and / or decreasing manner.

[0089] Preferably, on the inner surface 3, each of such curves has an at least partially increasing and at least partially decreasing radius of curvature, ie the radius of curvature increases for at least one section of the curve and decreases for at least one section of the curve.

[0090] For example, the radius of curvature R30 is smaller in the central part of the lens 1 and larger at the edge of the lens 1. In other words, the radius of curvature decreases from a determined value R30 at the center of the curve, toward the outside of the lens 1, to determined values ​​R30', R30" at the edge of the curve.

[0091] Thus, along the first inner central curve 30 , the thickness S of the lens 1 is greater in the central portion and smaller in the peripheral portion.

[0092] Therefore, according to an embodiment, the radius of curvature varies along the first inner center curve 30 such that R30′ and R30″ are smaller than R30.

[0093] For example, in the specific embodiment illustrated in the drawings, the radius of curvature R30 along the first inner central curve 30 at the center of the curve is substantially equal to 130 mm.

[0094] Still preferably, this trend is valid for all first inner curves.

[0095] In particular, in the specific embodiment shown in the accompanying drawings, along the other first inner curve, the curvature radii R32' and R32", R34' and R34", R36' and R36", R38' and R38" at the edges are smaller than the corresponding curvature radii R32, R34, R36, R38, R40, R42 at the center of the corresponding curve.

[0096] Still according to a preferred embodiment, the inner surface 3 has further radii of curvature R37, R35, R33, R39, R41, R43 along another second inner curve. Figure 7 As can be seen in FIG. 1 , these additional second inner curves are defined by the intersection lines of the inner surface 3 and the planes Y_10, Y_20, Y_30, Y_-10, Y_-20, Y_-30 parallel to the second plane Y_0. In particular, each radius of curvature R37, R35, R33, R39, R41, R43 changes continuously in an increasing and / or decreasing manner along the corresponding additional second inner curve.

[0097] Parallel planes Y_10, Y_20, Y_30, Y_-10, Y_-20, Y_-30 Figure 5 For example, the depicted parallel planes Y_10, Y_20, Y_30, Y_-10, Y_-20, Y_-30 are spaced 10 mm from each other.

[0098] Still preferably, the inner surface 3 has a curvature radius that changes continuously in an increasing and / or decreasing manner along each second inner curve, each second inner curve being defined by an intersection line of the inner surface 3 and any plane parallel to the second plane Y_0.

[0099] In other words, on the inner surface 3 , each additional first inner curve defined on the inner surface 3 by any plane parallel to Y_0 has a continuously varying non-constant radius of curvature.

[0100] Basically, preferably, not only the curvature radii of the further parallel planes Y_10, Y_20, Y_30, Y_-10, Y_-20, Y_-30, but also all planes parallel to the second plane Y_0 have curvature radii that vary continuously in an increasing and / or decreasing manner.

[0101] Preferably, on the inner surface 3, each of such curves has an at least partially increasing and at least partially decreasing radius of curvature, ie the radius of curvature increases for at least one section of the curve and decreases for at least one section of the curve.

[0102] For example, the radius of curvature R31 is larger in the central part of the lens 1 and smaller at the edge of the lens 1. In other words, the radius of curvature increases from a determined value R31 at the center of the curve toward the outside of the lens 1 to determined values ​​R31', R31" at the edge of the curve.

[0103] Therefore, along the second inner central curve 31 , the thickness S of the lens 1 is larger in the peripheral portion and smaller in the central portion.

[0104] Therefore, according to an embodiment, the radius of curvature varies along the second inner center curve 31 such that R31 ′ and R31 ″ are greater than R31 .

[0105] Still preferably, this trend is valid for all second inner curves.

[0106] In particular, along the further second inner curve, the radii of curvature R33' and R33", R35' and R35", R37' and R37", R39' and R39" at the edges are greater than the corresponding radii of curvature R33, R35, R37, R39, R41, R43 at the center of the corresponding curve.

[0107] Still according to a preferred embodiment, the outer surface 5 has further radii of curvature R50, R58, R60, R62, R56, R54, R52 along another first outer curve. Figure 8 As can be seen in FIG. 5 , these further first outer curves are defined by the intersections of the outer surface 5 with planes X_0, X_2, X_4, X_6, X_-2, X_-4, X_-6 spaced at an angle relative to the first plane X_0. In particular, each radius of curvature R50, R58, R60, R62, R56, R54, R52 is constant along the respective further first outer curves.

[0108] Still preferably, the radius of curvature of the outer surface 5 is constant along all further first outer curves and furthermore all radii of curvature R33, R35, R37, R39, R41, R43 along each further first outer curve are equal to one another.

[0109] In other words, preferably, R52 , R54 , R56 , R58 , R60 , R62 are equal to each other and are equal to the curvature radius R50 along the first outer curve 50 .

[0110] Still preferably, the outer surface 5 has a constant radius of curvature along each first outer curve, each first outer curve being defined by the intersection of the outer surface 5 with any plane angularly spaced relative to the first plane X_0. All radii of curvature along all first outer curves are preferably equal to each other.

[0111] Still according to a preferred embodiment, the outer surface 5 has further radii of curvature R57, R55, R53, R59, R61, R63 along another second outer curve. Figure 7 As can be seen in FIG. 5 , these additional second outer curves are defined by the intersection of the outer surface 5 and the planes Y_10, Y_20, Y_30, Y_-10, Y_-20, Y_-30 parallel to the second plane Y_0. In particular, each radius of curvature R53, R55, R57, R59, R61, R63 is constant along the corresponding additional second outer curve.

[0112] Still preferably, the radius of curvature of the outer surface 5 is constant along all further second outer curves. Furthermore, all radii of curvature R53, R55, R57, R59, R61, R63 along each further second outer curve are different from each other.

[0113] In other words, preferably, the radii of curvature R53, R55, R57, R59, R61, R63 are constant along the respective other second curves, but vary between one second curve and another. Still preferably, the radii of curvature R53, R55, R57, R59, R61, R63 also vary relative to the radius of curvature R51 along the second outer curve 51.

[0114] Still preferably, the outer surface 5 has a constant radius of curvature along each second outer curve, each second outer curve being defined by the intersection of the outer surface 5 with any plane parallel to the second plane Y_0. All radii of curvature along all first outer curves are preferably different from each other.

[0115] For example, the radius of curvature R53 is greater than the radius of curvature R55, the radius of curvature R55 is further greater than the radius of curvature R57, and the radius of curvature R57 is further greater than the radius of curvature R51.

[0116] In addition, the radius of curvature R51 is greater than the radius of curvature R59, and so on.

[0117] In other words, the radii of curvature between different second outer curves have a tendency to decrease from one side to the other side of the lens 1. Or conversely, the radii of curvature between different second outer curves have a tendency to increase from one side to the other side of the lens 1.

[0118] In the case of sun lenses, the invention allows providing a lens 1 in which the optical aberrations are reduced.

[0119] exist Fig. 9 , an exemplary image depicting the difference between the ideal case of a lens without optical aberrations (represented by the reference grid G1) and a lens 1 according to the invention (represented by the grid G2 associated with such a lens 1). As can be observed, the difference between the grid G2 associated with the lens 1 according to the invention and the reference grid G1 is minimal, due to the optimization of the surface shape (aimed at reducing the optical aberrations). In other words, the lens 1 according to the invention is close to the ideal case.

[0120] A suitable design of the lens 1 by providing the inner surface 3 with the radii of curvature R30 , R31 allows the optical properties of the lens 1 itself to be optimized in terms of spherical power, astigmatism and prismatic power.

[0121] A method for designing and / or manufacturing a lens 1 as described above also forms part of the present invention.

[0122] The method according to the invention is applicable to the design and / or production of both sun lenses and corrective or ophthalmic lenses.

[0123] This method involves identifying a target configuration of a lens 1 having certain desired aesthetic characteristics, wherein the outer surface 5 of the lens 1 itself is concave towards the outside (convex towards the wearer) along at least one vertical direction.

[0124] In particular, the method comprises a first step (a) of selecting a desired outer radius of curvature R50 for the outer surface 5 which is positive (relative to a center positioned to one side of the wearer's eye) and constant along at least a first outer center curve 50 .

[0125] This first step (a) further comprises still selecting a desired outer radius of curvature R51 for the outer surface 5 , which is negative (relative to a center positioned on one side of the wearer's eye) and constant along at least the second outer center curve 51 .

[0126] In other words, the first step (a) involves selecting constant radii of curvature R50, R51 for the outer surface 5, which are respectively positive along the first outer center curve 50 so as to give the lens 1 an outer concavity in the vertical direction, and are negative along the second outer center curve 51 so as to give the lens 1 an outer convexity in the horizontal direction.

[0127] The first step (a) is the same for both designing and / or manufacturing sun lenses and corrective or ophthalmic lenses.

[0128] In the case of designing and / or manufacturing a sun lens, the method comprises a subsequent step (b): calculating for the inner surface 3 an inner radius of curvature R30 varying along a first inner central curve 30 and an inner radius of curvature R31 varying along a second inner central curve 31, wherein such inner radii R30, R31 are calculated so as to minimize the optical aberrations of the semi-finished lens 10 having the above-mentioned outer surface 5 and inner surface 3.

[0129] In the case of designing and / or manufacturing corrective or ophthalmic lenses, the method comprises, after step (a), a step (b): calculating for the inner surface 3 an inner radius of curvature R30 varying along a first inner center curve 30 and an inner radius of curvature R31 varying along a second inner center curve 31, wherein such inner radii R30, R31 are calculated so as to give the semi-finished lens 10 having the above-mentioned outer surface 5 and inner surface 3 the desired optical focal length or gradient.

[0130] Therefore, the method comprises, after step (b), a further step (c): calculating the inner radii of curvature R30 and R31. Step (c) involves manufacturing a semi-finished lens 10 based on such desired outer radii of curvature R50, R51 and such calculated inner radii of curvature R30, R31, the semi-finished lens having an inner surface 3 and an outer surface 5, the inner surface being characterized by the inner radii of curvature R30, R31 as calculated above along the first inner central curve 30 and along the second inner central curve 31, so as to minimize aberrations or impart the desired optical power or gradient, and the outer surface being characterized by the outer radii of curvature R50, R51 as initially selected above along the first outer central curve 50 and along the second outer central curve 51.

[0131] In particular, such a step of manufacturing the semi-finished lens 10 preferably involves injection molding the semi-finished lens 10 .

[0132] Once the semi-finished lens 10 is manufactured, the method comprises a subsequent step (d): shaping the semi-finished lens 10 to achieve a lens 1 according to the present invention, i.e., a lens 1 having an inner radius of curvature R30 that continuously changes in an increasing and / or decreasing manner at least along the first inner center curve 30, and having an inner radius of curvature R31 that continuously changes in an increasing and / or decreasing manner at least along the second inner center curve 31.

[0133] Steps (c) and (d) are applicable to the design and / or manufacture of both sun lenses and corrective or ophthalmic lenses.

[0134] Preferably, step (a) comprises the following steps: selecting a plurality of desired outer radii of curvature along a plurality of corresponding outer curves. In other words, step (a) comprises the following steps: selecting a constant outer radius of curvature at the intersection of the outer surface 5 with a plurality of second planes Y_0, Y_10, Y_20, Y_30, Y_-10, Y_-20, Y_-30 and the first planes X_0, X_2, X_4, X_6, X_-2, X_-4, X_-6.

[0135] In the same manner, step (b) comprises the following steps: calculating a plurality of inner radii of curvature that vary along a plurality of corresponding inner curves that respectively correspond to the above outer curves for the inner surface 3. In other words, step (b) comprises the following steps: calculating an inner radius of curvature that varies (continuously in an increasing and / or decreasing manner) at the intersection of the inner surface 3 and the second plane Y_0, Y_10, Y_20, Y_30, Y_-10, Y_-20, Y_-30 that is the same as the outer radius of curvature for defining the outer surface 5 of the lens 1, and the first plane X_0, X_2, X_4, X_6, X_-2, X_-4, X_-6.

[0136] Preferably, in the case of designing and / or manufacturing a sun lens, the step (b) of calculating the variable inner radius of curvature to minimize optical aberrations comprises the following steps: calculating the variable inner radius of curvature that optimizes at least one of the spherical power, astigmatism and prismatic power of the lens 1.

[0137] Still more preferably, such step (b) comprises the step of calculating a modified internal radius of curvature that optimizes a weighted combination of the spherical power, the astigmatism and the prismatic power of the lens 1. In other words, since usually the optimum value of one of the three powers mentioned above does not correspond to the optimum values ​​of the other two, step (b) comprises the step of weighing by calculation the contribution given by each of the three powers in minimizing the optical aberrations, so as to find the modified internal radius of curvature that ensures the best overall compromise.

[0138] The lens thus envisaged, as well as the eyewear comprising such a lens and the method for designing and / or manufacturing such a lens, are susceptible to numerous modifications and variations, all of which fall within the scope of the inventive concept; moreover, all the details may be replaced by technically equivalent elements.

[0139] In practice, the material used may be any material, depending on the technical requirements, as long as it is compatible with the specific use and has the required size and shape.

Claims

1. A lens (1) for spectacles and / or face masks, said lens (1) having an inner surface (3) tending to point towards at least one eye of a wearer and an outer surface (5) opposite said inner surface (3); said inner surface (3) and said outer surface (5) being spaced from each other so as to define a thickness (S); A first inner center curve (30) and a second inner center curve (31) are defined on the inner surface (3) of the lens (1); a first outer center curve (50) and a second outer center curve (51) are defined on the outer surface (5) of the lens (1); The first inner center curve (30) and the first outer center curve (50) are respectively defined by intersection lines of the inner surface (3) and the outer surface (5) with a first plane (X_0) passing through the geometric center of the lens (1) and extending in a substantially vertical direction; The second inner center curve (31) and the second outer center curve (51) are respectively defined by the intersection lines of the inner surface (3) and the outer surface (5) with a second plane (Y_0) passing through the geometric center of the lens (1); the second plane (Y_0) is inclined at an angle between -25° and 25° relative to the horizontal direction; It is characterized in that Towards the eye of the wearer, the inner surface (3) is convex at least along the first inner central curve (30) and concave at least along the second inner central curve (31); Towards the wearer's eye, the outer surface (5) is convex at least along the first outer central curve (50) and concave at least along the second outer central curve (51).

2. The lens (1) according to claim 1, wherein: - the inner surface (3) has a radius of curvature (R30) that varies continuously in an increasing and / or decreasing manner, at least along the first inner center curve (30); The inner surface (3) has, at least along the second inner center curve (31), a radius of curvature (R31) that varies continuously in an increasing and / or decreasing manner.

3. The lens (1) according to claim 2, wherein: The radius of curvature (R30) of the inner surface (3) at least partially increases and at least partially decreases along the first inner center curve (30); the radius of curvature (R31) of the inner surface (3) at least partially increases and at least partially decreases along the second inner center curve (31).

4. The lens (1) according to claim 2 or 3, wherein: The outer surface (5) has a constant radius of curvature (R50) at least along the first outer center curve (50).

5. The lens (1) according to any one of claims 2 to 4, wherein: The outer surface (5) has a constant radius of curvature (R51) at least along the second outer center curve (51).

6. The lens (1) according to any one of claims 2 to 5, wherein: The thickness (S) varies continuously.

7. The lens (1) according to any one of claims 2 to 6, wherein: The inner surface (3) has additional radii of curvature (R38, R40, R42, R36, R34, R32) along an additional first inner curve, and the additional first inner curve is defined by the intersection of the inner surface (3) and a first plane (X_2, X_4, X_6, X_-2, X_-4, X_-6) spaced apart at an angle relative to the first plane (X_0), and each additional radius of curvature changes continuously in an increasing and / or decreasing manner along the corresponding additional first inner curve.

8. The lens (1) according to claim 7, wherein: The inner surface (3) has a radius of curvature that changes continuously in an increasing and / or decreasing manner along any first inner curve, and any first inner curve is defined by the intersection of the inner surface (3) and any plane angularly spaced apart relative to the first plane (X_0).

9. The lens (1) according to any one of claims 2 to 8, wherein: The inner surface (3) has another curvature radius (R37, R35, R33, R39, R41, R43) along another second inner curve, and the other second inner curve is defined by the intersection of the inner surface (3) and a second plane (Y_10, Y_20, Y_30, Y_-10, Y_-20, Y_-30) parallel to the second plane (Y_0), and each other curvature radius changes continuously in an increasing and / or decreasing manner along the corresponding other second inner curve.

10. The lens (1) according to claim 9, wherein: The inner surface (3) has a curvature radius that changes continuously in an increasing and / or decreasing manner along any second inner curve, and any second inner curve is defined by the intersection of the inner surface (3) and any plane parallel to the second plane (Y_0).

11. The lens (1) according to any one of the preceding claims, wherein: The outer surface (5) is cylindrical.

12. The lens (1) according to any one of the preceding claims, wherein: The second plane (Y_0) extends in a substantially horizontal direction.

13. The lens (1) according to any one of the preceding claims, wherein: The first plane (X_0) is inclined at a second angle (β) between -30° and +30° relative to a vertical plane.

14. An eyewear (100) comprising at least one lens (1) for spectacles and / or masks, said lens (1) having an inner surface (3) tending to be directed towards at least one eye of a wearer and an outer surface (5) opposite said inner surface (3); said inner surface (3) and said outer surface (5) being spaced from each other so as to define a thickness (S); A first inner center curve (30) and a second inner center curve (31) are defined on the inner surface (3) of the lens (1); a first outer center curve (50) and a second outer center curve (51) are defined on the outer surface (5) of the lens (1); The first inner center curve (30) and the first outer center curve (50) are respectively defined by intersection lines of the inner surface (3) and the outer surface (5) with a first plane (X_0) passing through the geometric center of the lens (1) and extending in a substantially vertical direction; The second inner center curve (31) and the second outer center curve (51) are respectively defined by the intersection lines of the inner surface (3) and the outer surface (5) with a second plane (Y_0) passing through the geometric center of the lens (1); the second plane (Y_0) is inclined at an angle between -25° and 25° relative to the horizontal direction; It is characterized in that Towards the eye of the wearer, the inner surface (3) is convex at least along the first inner central curve (30) and concave at least along the second inner central curve (31); Towards the wearer's eye, the outer surface (5) is convex at least along the first outer central curve (50) and concave at least along the second outer central curve (51).

15. An eyewear comprising at least one lens (1) for spectacles and / or masks, said lens (1) having an inner surface (3) tending to be directed towards at least one eye of the wearer and an outer surface (5) opposite said inner surface (3); said inner surface (3) and said outer surface (5) being spaced from each other so as to define a thickness (S); A first inner center curve (30) and a second inner center curve (31) are defined on the inner surface (3) of the lens (1); a first outer center curve (50) and a second outer center curve (51) are defined on the outer surface (5) of the lens (1); The first inner center curve (30) and the first outer center curve (50) are respectively defined by intersection lines of the inner surface (3) and the outer surface (5) with a first plane (X_0) passing through the geometric center of the lens (1) and extending in a substantially vertical direction; The second inner center curve (31) and the second outer center curve (51) are respectively defined by the intersection lines of the inner surface (3) and the outer surface (5) with a second plane (Y_0) passing through the geometric center of the lens (1); the second plane (Y_0) is inclined at an angle between -25° and 25° relative to the horizontal direction; It is characterized in that Towards the eye of the wearer, the inner surface (3) is convex at least along the first inner central curve (30) and concave at least along the second inner central curve (31); Towards the eye of the wearer, the outer surface (5) is convex at least along the first outer central curve (50) and concave at least along the second outer central curve (51); in: - the inner surface (3) has a radius of curvature (R30) that varies continuously in an increasing and / or decreasing manner, at least along the first inner center curve (30); The inner surface (3) has, at least along the second inner center curve (31), a radius of curvature (R31) that varies continuously in an increasing and / or decreasing manner.

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