Spectacle lens, spectacles, computer-implemented method for designing a spectacle lens and method for manufacturing a spectacle lens

Abstract

A spectacle lens (1) is provided with - a lens back surface facing the eye (11); - a front surface of the spectacle lens facing away from the eye (13); - a Fresnel structure (3) comprising at least two Fresnel zones (3-1 to 3-6) and providing a focusing effect, wherein the focusing effect of the Fresnel structure (3) is based at least partially on a gradient of the refractive index within the Fresnel zones (3-1 to 3-6) and the Fresnel structure (3) has interfaces (5a to 5e) where a high refractive index of a Fresnel zone (3-1 to 3-6) and a low refractive index of an adjacent Fresnel zone (3-1 to 3-6) meet. The at least one interface (5a to 5e) has a rear intersection line (4a to 4e) with the posterior lens surface (11) and a front intersection line (6a to 6e) with the anterior lens surface (13).The posterior surface area of ​​the spectacle lens (11) enclosed by the innermost posterior cutting line (4a) has a posterior geometric centroid (PS), and the anterior surface area of ​​the spectacle lens (11) enclosed by the innermost anterior cutting line (6a) has an anterior geometric centroid (AC). For at least 25% of all azimuth angles, the posterior cutting line (4a to 4e) is closer to the posterior geometric centroid (PS) than the anterior cutting line (6a to 6e) is to the anterior geometric centroid (AC).

Description

[0001] The present invention relates to a spectacle lens with a Fresnel structure providing a focusing effect. The invention also relates to a computer-implemented method for designing such a spectacle lens and a method for manufacturing such a spectacle lens.

[0002] Conventional eyeglass lenses become thicker and heavier the higher the required vision correction. Weight reduction is achieved not only through the choice of material but primarily by reducing the dimensions, i.e., by choosing a smaller frame.

[0003] Weight is particularly relevant for vision correction applications in the field of augmented reality (AR glasses), as the system weight is already significantly higher than that of a conventional spectacle lens due to the additional components such as fiber optics, cameras, sensors, etc. However, reducing the diameter is often not a viable option here because of the necessary size of the fiber optics for projecting the virtual image into the wearer's field of vision.

[0004] For example, Fresnel structures for weight reduction in spectacle lenses are known from EP 0 927 905 A, GB 1,154,360 A, JP 2019174647 A and US 2013 / 0120707 A1. However, Fresnel structures are challenging to manufacture due to their sharp steps. Furthermore, the susceptibility of exposed Fresnel structures to contamination necessitates additional covering / filling. Additionally, the steps of Fresnel structures lead to shading effects and light scattering.

[0005] Furthermore, gradient index lenses (GRIN lenses) for ophthalmic applications are known from WO 2018 / 134037 A2, but these offer no weight advantages compared to a classic glass with a constant refractive index.

[0006] US patent 2022 / 0252931 A1 shows a segmented liquid crystal optic that can be used as a Fresnel GRIN lens with variable refractive power in augmented reality devices.

[0007] Fresnel-GRIN lenses, i.e., lenses in which the Fresnel structure is realized through variations in the refractive index, are known from the micro-optics literature for coupling light into optical fibers. Examples of publications on micro-optic Fresnel-GRIN lenses include, for example, Suhara et al., “Graded-index Fresnel lenses for integrated optics”, Appl. Opt. 21 (1982), pp. 1966–1971; P. Dellulier et al., “Femtosecond Laser Direct Writing of Gradient Index Fresnel Lens in GeS2-Based Chalcogenide Glass for Imaging Applications”, Appl. Sci 12 (2022), 4490; and R. Buczynski et al. 2019, “Achromatic nanostructured gradient index microlenses”, Optics Express, vol. 27, no. 7, pp. 9588-9600. The Fresnel-GRIN lenses described therein are designed for use in the infrared spectral range.

[0008] Diffractive Fresnel-GRIN lenses are described in A. Zhang, “Multifocal diffractive lens design in ophthalmology”, Applied Optics, Vol. 59, No. 31 (November 1, 2020), pp. 9807-9823. Diffractive Fresnel-GRIN lenses are used, for example, in intraocular lenses to create, in addition to the refractive focal point determined by the geometric shape of the intraocular lens, a second point of sharp vision determined by the diffractive effect of the Fresnel structure. This allows the intraocular lens to provide sharp vision at different distances.

[0009] Contact lenses designed as Fresnel-GRIN lenses are known from WO 97 / 10527 A1.

[0010] In contrast to the aforementioned prior art, a first object of the present invention is to provide an advantageous spectacle lens and advantageous spectacles with a Fresnel structure providing a focusing effect, in which the focusing effect of the Fresnel structure is based at least partially on a gradient of the refractive index within the Fresnel zones. For the purposes of this invention, the term "focusing effect" is, according to DIN EN ISO 13666:2019-12, section 3.10.2, a collective term for the spherical and astigmatic vertex power of a spectacle lens, which, according to DIN EN ISO 13666:2019-12, section 3.10.7, is in turn the reciprocal of the paraxial focal length of the spectacle lens.

[0011] A second object of the present invention is to provide a computer-implemented method for designing a spectacle lens, as well as a computer program and a computer for carrying out the method.

[0012] Finally, a third object of the present invention is to provide an advantageous method for manufacturing a spectacle lens.

[0013] The first problem is solved by a spectacle lens according to claim 1 and by spectacles according to claim 26, the second problem by a computer-implemented method according to claim 18, and the third problem by a method according to claim 25. The dependent claims contain advantageous embodiments of the invention.

[0014] According to a first aspect of the invention, a spectacle lens is provided. The term "spectacle lens" is intended to encompass both unprocessed round spectacle lenses and spectacle lenses adapted to a spectacle frame. Furthermore, the term "spectacle lens" is also intended to include numerical representations of spectacle lenses. A spectacle lens according to the invention can therefore be in the form of a physical spectacle lens or a numerical model of a spectacle lens.

[0015] A spectacle lens according to the invention has a rear surface facing the eye, a front surface facing away from the eye, and a Fresnel structure comprising at least two Fresnel zones. The Fresnel structure provides a focusing effect which, in at least one of the Fresnel zones, in particular in a plurality of the Fresnel zones or in all Fresnel zones, is based at least partially, but in particular completely, on a gradient of the refractive index within the corresponding Fresnel zone, and has interfaces at which a high refractive index of one Fresnel zone and a low refractive index of an adjacent Fresnel zone meet. A Fresnel structure that provides a focusing effect differs from a Fresnel structure that provides a diffractive effect in its structural dimensions, in particular in the width and / or height of the Fresnel zones.Within the scope of the present invention, the minimum width of a Fresnel zone is 0.5 mm and preferably 1 mm. In contrast, in diffractive Fresnel structures, the Fresnel zones typically have widths of less than 0.25 mm and heights that result in path length differences of less than 20 µm, preferably less than 10 µm, and typically less than 5 µm.

[0016] A Fresnel structure is understood to be a structure comprising at least two zones, so-called Fresnel zones, which has a jump in the arrow height and / or a jump in the refractive index at the boundary between adjacent zones.

[0017] At least one boundary surface has a rear intersection line with the rear surface of the spectacle lens and a front intersection line with the front surface of the spectacle lens. The rear surface area of ​​the spectacle lens enclosed by the innermost rear intersection line has a rear geometric centroid, and the front surface area of ​​the spectacle lens enclosed by the innermost front intersection line has a front geometric centroid.

[0018] In the spectacle lens according to the invention, the posterior cutting line is located closer to the posterior geometric center of gravity than the anterior cutting line is located closer to the anterior geometric center of gravity for at least 25% of all azimuth angles, preferably for at least 50% of all azimuth angles, and more preferably for at least 90% of all azimuth angles. In particular, the posterior cutting line can be located closer to the posterior geometric center of gravity than the anterior cutting line is to the anterior geometric center of gravity for any arbitrarily specified azimuth angle.In particular, in the spectacle lens according to the invention, for at least two interfaces and preferably for all interfaces, the rear intersection line of the respective interface can have a smaller distance from the rear geometric center of gravity than the front intersection line of this respective interface from the front geometric center of gravity for at least 25% of all azimuth angles, preferably for at least 50% of all azimuth angles and further preferably at least 90% and in particular for any arbitrarily specified azimuth angle.

[0019] For the purposes of the invention, the azimuth angle is defined as the angle between a straight line passing through the geometric centroid of the enclosed front surface area of ​​the spectacle lens in a tangent plane tangential to that area, and a straight reference line also passing through the geometric centroid of the enclosed front surface area in this tangent plane. The azimuth angle of a connecting line running on the front surface of the spectacle lens, which connects the geometric centroid of the enclosed front surface area to a point on a front-side intersection line of a boundary surface via the shortest path, is then the azimuth angle between the projection of this connecting line onto the tangent plane and the reference line running in the tangent plane.Within the scope of the present invention, this azimuth angle is also considered to be the azimuth angle of the point connected by the corresponding connecting line to the geometric centroid of the enclosed front surface area. Similarly, the azimuth angle of a connecting line running on the posterior surface of the spectacle lens, which connects the geometric centroid of the enclosed rear surface area to a point on a rear cross-sectional line of a boundary surface via the shortest path, is the azimuth angle between the projection of this connecting line onto the tangent plane and the reference line running in the tangent plane. Within the scope of the present invention, this azimuth angle is also considered to be the azimuth angle of the point connected by the corresponding connecting line to the geometric centroid of the enclosed rear surface area.Instead of a tangential plane that runs tangentially to the geometric centroid of the enclosed front surface area of ​​the spectacle lens front surface, a tangential plane that runs tangentially to the geometric centroid of the enclosed rear surface area of ​​the spectacle lens back surface can also be used to determine the azimuth angle.

[0020] The inventive design of the interface between adjacent Fresnel zones reduces disturbing shadows and reflections at the interface for eyeglass wearers by appropriately aligning the interface, for example, by tilting it. Its orientation can also be adapted to the respective viewing direction when looking along the interface. In particular, it is possible to individually adjust the orientation to each eyeglass wearer. Alternatively, a standard eye based on average values ​​and a standard head geometry can be used as the basis for aligning the interface in the respective viewing direction. Overall, the tilting of the interface and the associated reduction of shadows and reflections increases the wearing comfort of an eyeglass lens with a Fresnel structure based on gradients in the refractive index.

[0021] In the spectacle lens according to the invention, at least one interface or several interfaces, in particular all interfaces, can be oriented such that the rays which run within a section plane along this interface converge after exiting the back surface of the spectacle lens at a point located on the side of the back surface of the spectacle lens and spaced apart from it.The plane of intersection is the plane in which a front connecting line runs at a specific azimuth angle in the front surface of the spectacle lens, connecting the geometric centroid of the enclosed front surface area to a point on the front intersection line of one of the interface surfaces via the shortest path, and in which a rear connecting line runs at the same specific azimuth angle in the back surface of the spectacle lens, connecting the geometric centroid of the enclosed back surface area to a point on the rear intersection line of the same interface surface via the shortest path. In particular, this point, located on and spaced from the side of the back surface of the spectacle lens, can be the same for all azimuth angles, whereby the rays then travel along a conical surface.In this way, the spectacle lens can be designed such that all rays running along an interface converge, after exiting the back surface of the spectacle lens, at the center of the pupil, at the center of the eye's rotation, or at a point lying on a straight line passing through the center of the pupil and the center of the eye's rotation in the zero-viewing direction. Within the scope of the invention, the zero-viewing direction is considered to be the horizontal fixation line that, when looking straight ahead without correction and with a habitual head and body posture, leads to an object at infinity (see DIN EN ISO 13666:2019-12, Section 3.2.25).In the context of the invention, the conical surface is to be understood as a surface obtained by connecting the points of a rear section line with a point that is spaced from the rear surface of the spectacle lens in a coordinate along the surface normal at the geometric centroid of the enclosed rear surface area.

[0022] In alternative designs, the distance of the point located on the side of the lens's back surface from the lens's back surface can also depend on the azimuth angle. This makes it possible, for example, to specify a different point for an azimuthal orientation of the cutting plane, corresponding to the wearer's horizontal gaze, than for an azimuthal orientation of the cutting plane, corresponding to the wearer's vertical gaze. This allows, for instance, consideration of the fact that the eye tends to roll horizontally rather than vertically. Thus, for horizontal gaze directions, the rays can converge at the eye's center of rotation, while for vertical gaze directions, which are typically less varied, the rays can converge at the pupil's center.In other words, the Fresnel structure can be optimized for horizontal viewing directions for a moving eye and for vertical viewing directions for a stationary eye.

[0023] In the spectacle lens according to the invention, at least two of the interfaces, and in particular all interfaces, can be oriented such that, for each interface, all rays running along these interfaces within the plane of section converge after exiting the back surface of the spectacle lens at a point located on the side of the back surface of the spectacle lens and spaced apart from it, and the point located on the side of the back surface of the spectacle lens and spaced apart from it is the same for the at least two interfaces. For example, if the spectacles are primarily intended for use with a resting eye, it is advantageous to orient at least two of the interfaces, and preferably all of the interfaces, such that the rays converge at the center of the pupil.

[0024] However, it is also possible that at least two of the interfaces, and in particular all interfaces, are oriented such that, for each interface, all rays running along the interface within the plane of intersection converge after exiting the lens back surface at a point located on and spaced apart from the lens back surface, and that the distance of this point from the lens back surface differs for the at least two interfaces. For example, the innermost interface or interfaces can be oriented such that the rays converge at the center of the pupil, whereas the outermost interface or interfaces can be oriented such that the rays converge at the eye's center of rotation.In this way, the eye can be treated like a stationary eye for small eye movements and like a rolling eye for large eye movements. Furthermore, it is possible to design the distance of the point located on the side of the lens's back surface, and thus the point of rejection, differently for each interface. For example, the innermost interface can be oriented so that the rays converge at the pupil's center, and the outermost interface so that the rays converge at the eye's center of rotation. The interfaces in between can then be oriented so that the rays converge at different points along a straight line passing through the pupil's center and the eye's center of rotation in the zero-viewing direction.A lens equipped in this way is optimized for narrow viewing angles with respect to a stationary eye, and its optimization changes with increasing viewing angle, shifting from the stationary eye to the rolling eye. By appropriately selecting the point where the rays converge, or the points where rays traveling along different interfaces converge after exiting the lens's back surface, the lens can be particularly well adapted to the wearer and the intended use of the glasses.

[0025] The spectacle lens according to the invention can be manufactured particularly easily if at least one of the interfaces, and in particular all interfaces, run along a straight line within the cutting plane. Alternatively, at least one of the interfaces can run along a curved line within the cutting plane. The curvature of the curved line is: - a curvature that follows the path of a light ray originating from the point spaced from the back surface of the spectacle lens and entering the spectacle lens at the boundary between the high refractive index of one Fresnel zone and the low refractive index of the adjacent Fresnel zone through the back surface of the spectacle lens immediately adjacent to the interface (5a to 5e) on the side of the high refractive index; - a curvature that follows the path of a light ray originating from a point spaced from the back surface of the lens and entering the lens at the boundary between the high refractive index of one Fresnel zone and the low refractive index of the adjacent Fresnel zone, passing through the back surface of the lens immediately adjacent to the interface on the side of the low refractive index; or - a curvature whose path lies between the paths of the aforementioned light rays.

[0026] The point from which the light ray originates, i.e., the point where the rays converge, can be the center of the pupil, the center of rotation of the eye, or a point lying on a straight line passing through the center of the pupil and the center of rotation in the zero viewing direction. By designing the interface as a curved surface, vignetting and reflections can be particularly well avoided. Here, too, the lens can be optimally adapted to the wearer and their use of the glasses by appropriately selecting the point or points from which the light ray originates. The point from which the light ray originates can be the same point for at least two interfaces, and in particular for all interfaces. However, there can also be at least two interfaces for which different points exist, spaced apart from the back surface of the lens.

[0027] In its negative lens configuration, the spectacle lens typically has a dead zone for each interface. These dead zones are defined by the path of a set of first light rays within the lens, by the path of a set of second light rays within the lens, and by an annular region on the lens's front surface resulting from the path of the first and second light rays. For each interface, the first light rays are those rays that originate from, or converge at, a point located at the rear surface of the lens and enter the Fresnel zone with its high refractive index immediately adjacent to the corresponding interface. The second light rays are those rays that originate from, or converge at, a point located at the rear surface of the lens and enter the Fresnel zone with its high refractive index immediately adjacent to the interface.The two surfaces are joined at this point and enter the Fresnel zone with its low refractive index adjacent to the corresponding interface through the back surface of the lens. Due to the different refractive indices on either side of the interface, the light rays incident on the different sides of the respective interface are refracted differently, which in turn leads to the described dead zones. Although these dead zones do not contribute to image formation, the interface located within the dead zone can still cause scattered light and reflections. To reduce scattered light and reflections, in an advantageous embodiment of the lens according to the invention, the dead zones are each provided with at least one light-absorbing layer.A light-absorbing layer may be present along the path of the quantity of first rays and / or a light-absorbing layer may be present along the path of the quantity of second rays and / or a light-absorbing layer may be present in the ring-shaped area of ​​the front surface of the spectacle lens.

[0028] If at least one of the interfaces, and in particular all interfaces, run along a straight line within the section plane described above, it is advantageous if this straight line(s) is / are oriented such that it lies within the dead zone. Such a design of the spectacle lens also enables the reduction of scattered light and reflections.

[0029] To reduce stray light and reflections, the dead zones of the spectacle lens can have a different refractive index than the high and low refractive indices of the Fresnel zones adjacent to the respective dead zone. This can be achieved, for example, by doping the corresponding parts of the lens or by using a different material for manufacturing these parts. Furthermore, the dead zone can be used for a continuous transition in refractive index, which may be preferable to a sharp break for reducing reflections, etc.

[0030] The measures mentioned above for reducing stray light and reflections can be used alternatively or cumulatively.

[0031] The spectacle lens according to the invention can have a central area without a Fresnel structure and with a curved surface. This central area can have a diameter of up to 20 mm. In particular, the central area can have a diameter between 5 mm and 20 mm, especially between 10 mm and 15 mm. In this case, the Fresnel structure is only present in an area outside the central region. The spectacle lens then provides a focusing effect in the center due to the curved surface and in the periphery due to the Fresnel structure. With such a design of the spectacle lens, a good compromise between thickness / weight on the one hand and image quality on the other can be achieved without image distortions occurring in the periphery of the spectacle lens, as is otherwise common with surface shapes of this type.At the same time, the chromatic aberration can be significantly improved compared to a lens where the refractive effect relies solely on a curved surface all the way to the edge, provided there is low dispersion at the high refractive index and high dispersion at the low refractive index. In lenses designed as positive lenses, the Fresnel structure can be implemented as a flat plate or meniscus of constant thickness if its focusing effect is based exclusively on a gradient of refractive index within the Fresnel zones. In lenses designed as negative lenses, the thickness can also decrease towards the edge. Due to the decoupling of surface shape and focusing effect made possible by the Fresnel structure, many variations are conceivable.

[0032] The resolution of a Fresnel structure for ophthalmic applications is limited by the structure width, which should ideally be larger than a certain fraction of the pupil (e.g., ≥ 1 mm or at least ≥ 0.5 mm). With a strong focusing effect, this leads to thick elements in Fresnel structures whose focusing effect is based on a gradient of the refractive index within the Fresnel zones, and to large jumps in the arrow height in Fresnel structures whose focusing effect is based on curved or inclined surfaces of the Fresnel zones. It can therefore be advantageous to combine a Fresnel structure whose focusing effect is based on a gradient of the refractive index within the Fresnel zones with a Fresnel structure whose focusing effect is based on curved or inclined surfaces of the Fresnel zones.It is therefore advantageous if the spectacle lens according to the invention, in addition to a Fresnel structure whose focusing effect is based at least partially on a gradient of the refractive index within the Fresnel zones, includes an additional Fresnel structure which has Fresnel facets with curved and / or inclined surfaces and in which there are jumps in the arrow height at the boundaries between adjacent Fresnel facets, i.e. a Fresnel structure in which the focusing effect is based on the curvature and in particular the inclination of the surfaces of the Fresnel facets.In such a combined Fresnel structure, the thickness of the Fresnel structure, whose focusing effect is based on a gradient of the refractive index within the Fresnel zones, can be reduced while maintaining the strong focusing effect, compared to a non-combined Fresnel structure (i.e., a Fresnel structure whose focusing effect is based solely on a gradient of the refractive index within the Fresnel zones). Simultaneously, in the combined Fresnel structure, the jumps in the sag of the Fresnel structure, whose focusing effect is based on curved surfaces of the Fresnel zones, can be reduced compared to a non-combined Fresnel structure (i.e., a Fresnel structure whose focusing effect is based solely on curved surfaces of the Fresnel zones).

[0033] To combine a Fresnel structure whose focusing effect is based on a gradient of the refractive index within the Fresnel zones with a Fresnel structure whose focusing effect is based on curved and / or inclined surfaces of the Fresnel zones, for example, a Fresnel structure whose focusing effect is based on curved and / or inclined surfaces of the Fresnel zones can additionally be provided with variations in the refractive index within the Fresnel zones. This approach offers the advantage that the jumps in the arrow height coincide with the interfaces between a high refractive index of a Fresnel zone and a low refractive index of an adjacent Fresnel zone. However, this is not necessary within the scope of the present invention.

[0034] In the combined Fresnel structure, the variations in refractive index can be limited to that section of the Fresnel structure over which the curved and / or inclined surfaces of the Fresnel zones with the jumps in the arrow heights rise. If the variations in refractive index also extend to that section of the Fresnel structure which has the curved and / or inclined surfaces and the jumps in the arrow heights, the curvatures and / or inclinations of the surfaces of the Fresnel zones must be adjusted to the variation in refractive index within the Fresnel zone.

[0035] In the combined Fresnel structure, the jumps in the arrow heights can be formed by flanks of the Fresnel facets, which may continue the course of the interfaces up to a kink caused by the law of refraction at the interface between the Fresnel structure whose focusing effect is based on a gradient of the refractive index within the Fresnel zones and the Fresnel structure whose focusing effect is based on curved and / or inclined surfaces of the Fresnel zones.

[0036] The gradient of the refractive index within the Fresnel zones of the spectacle lens according to the invention is particularly non-linear, i.e., the refractive index increases in the radial direction according to a spherical or aspherical profile. For example, a parabolic or hyperbolic profile is possible as an aspherical profile. However, other aspherical profiles are also possible. Furthermore, the radii of curvature do not need to be the same in all radial directions, for example, when astigmatism correction is required.

[0037] The gradient of the refractive index within the Fresnel zones of the spectacle lens according to the invention can also exhibit a linear increase in the radial direction. Linear increases offer the advantage of potentially being easier to manufacture than non-linear refractive index gradients. However, in the case of a linear refractive index gradient, an adaptation of the lens surface is necessary. This adaptation can be achieved, for example, by the described combination with a Fresnel structure whose focusing effect is based on curved and / or inclined surfaces of the Fresnel zones. In the spectacle lens according to the invention, the adaptation can also be achieved by a lens surface without discontinuities in the arrow height. The lens has a front surface and / or a back surface that has a kink at the boundary between two Fresnel zones.In this case, a surface would result that locally generates the curvature of the wavefront, while the gradient of the refractive index is responsible for the beam deflection according to the desired focusing effect. Compared to a combination with a Fresnel structure, whose focusing effect is based on curved and / or inclined surfaces of the Fresnel zones, this approach offers the advantage that less complex measures are required to prevent contamination of the lens surface, and the lens surface is also easier to clean.

[0038] In order to design the spectacle lens according to the invention as an achromatic spectacle lens, two materials can be combined in the spectacle lens in such a way that color errors are at least partially compensated and / or a low dispersion can be combined with the high refractive index and a high dispersion with the low refractive index.

[0039] According to a second aspect of the invention, a computer-implemented method for designing a spectacle lens according to the invention is provided. The computer-implemented method comprises the following steps: - Recording at least correction data that represent at least the correction to be achieved with the spectacle lens, and distance data that represent at least the distance of the pupil center or the eye rotation center from the vertex of the spectacle lens back surface, or from which at least the distance of the pupil center or the eye rotation center from the vertex of the spectacle lens back surface can be derived; - Determining the Fresnel structure based on the correction data and the distance data.

[0040] The collected correction and distance data can be standardized, particularly in the case of distance data, statistically derived from a sufficiently large group of test subjects. Alternatively, they can be individualized, meaning data measured for a specific spectacle wearer. The latter offers the advantage of allowing the lens to be individually tailored to the wearer. It is also possible, for example, to determine the correction data individually and use standardized distance data for this purpose. If both the correction and distance data are standardized, stock lenses can be generated for a number of combinations of correction and distance data.

[0041] The procedure can also include, in particular, the measurement of the vertex distance, i.e., the distance between the vertex of the lens back surface and the apex of the wearer's cornea. The distance of the pupil center from the vertex of the lens back surface can then be determined using the vertex distance and the distance of the pupil center from the apex of the wearer's cornea. Similarly, the distance of the eye's center of rotation from the vertex of the lens back surface can be determined using the vertex distance and the distance of the eye's center of rotation from the apex of the wearer's cornea. A statistically averaged, standardized distance of the eye's center of rotation from the apex of the cornea is 13.5 ± 2.5 mm.

[0042] The computer-implemented method may in particular also include a step of outputting a numerical representation of the designed spectacle lens for use in the manufacture of a physical spectacle lens corresponding to the numerical representation of the spectacle lens by means of a computer-aided numerically controlled (CNC) manufacturing process.

[0043] According to the second aspect of the invention, a non-volatile, computer-readable storage medium with a numerical representation of the spectacle lens according to the invention is also provided for use in the manufacture of a physical spectacle lens corresponding to the numerical representation of the spectacle lens by means of a computer-aided numerically controlled (CNC) manufacturing process.

[0044] Furthermore, according to the second aspect of the invention, a computer system is provided with data that can be retrieved via a network and which provides a numerical representation of the spectacle lens according to the invention for use in the manufacture of a physical spectacle lens corresponding to the numerical representation of the spectacle lens by means of a computer-aided numerically controlled (CNC) manufacturing process.

[0045] Furthermore, according to the second aspect of the invention, a computer program with instructions that cause a computer to carry out the computer-implemented method according to the invention is provided when the instructions are executed by the computer.

[0046] Finally, according to the second aspect of the invention, a data processing system is provided comprising a memory that stores instructions that cause the data processing system to carry out the computer-implemented method, and a processor for executing the instructions stored in the memory.

[0047] According to a third aspect of the invention, a method for manufacturing a spectacle lens is provided. In this method, a physical spectacle lens corresponding to the numerical representation of the spectacle lens according to the invention is manufactured using a computer-aided, numerically controlled manufacturing process based on a numerical representation of the spectacle lens. The computer-aided, numerically controlled manufacturing process can, in particular, be an additive manufacturing process such as 3D printing. Alternatively, the computer-aided, numerically controlled manufacturing process can be a manufacturing process in which a photosensitive material is selectively exposed by means of structured illumination and / or suitable masks. Furthermore, methods are conceivable in which, for example, in a first step...By winding or stacking thin polymer films, such as those already used for GRIN lenses, a cylindrical or cubic blank is first produced. This blank, if necessary after forming, exhibits a Fresnel structure with a gradient of refractive index within the Fresnel zones, and its diameter corresponds to the diameter of the later, unprocessed round spectacle lens. In a subsequent step, unprocessed round spectacle lenses can then be cut from the cylindrical blank.

[0048] A pair of glasses according to the invention is equipped with at least one lens according to the invention. The advantages associated with the glasses according to the invention arise directly from the advantages described with regard to the lens according to the invention.

[0049] The glasses according to the invention can further comprise a display, a light guide, an input element for coupling a beam of light emanating from the display into the light guide, and an output structure for coupling the beam of light from the light guide towards the eye of a wearer of the glasses. For example, an air gap can be present between the light guide and the lens, which enables the beam of light to be guided inside the light guide by means of total internal reflection. However, instead of an air gap between the light guide and the lens, a layer of a material with a refractive index lower than that of the light guide can also be present between the light guide and the lens. In this embodiment as well, the beam of light can be guided inside the light guide by means of total internal reflection.

[0050] Because the Fresnel structure of the spectacle lens provides a focusing effect which, in at least one of the Fresnel zones, in particular in a majority of the Fresnel zones or in all Fresnel zones, is based at least partially, but especially completely, on a gradient of the refractive index within the corresponding Fresnel zone, the thickness of the spectacle lens can be kept low, even if the spectacle lens is designed to correct a strong refractive error, so that the combination of the spectacle lens with a light guide can also have a relatively low thickness.

[0051] The display can be an LED display, an LCD display, an OLED display, or any other suitable display. A prism, for example, can be used as the coupling element. Its prism faces are shaped and inclined in such a way that a beam of light emanating from the display is guided into the optical fiber in such a manner that it is directed to the output coupling structure via reflections at the optical fiber surfaces, particularly total internal reflection. The output coupling structure can be a diffraction grating, a partially transparent, inclined mirror, or partially transparent Fresnel elements. In the case of a diffraction grating, the beam of light is coupled out of the lens, for example, via the first-order diffraction maximum, while the observation light can pass through the output coupling structure with minimal interference via the zero-order diffraction maximum.

[0052] Further features, properties and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying figures. Features of the individual exemplary embodiments can also be combined with one another. Fig. Figure 1 shows the general structure of a Fresnel structure, in which the focusing effect is based on a gradient in the refractive index within the Fresnel zones. Fig. Figure 2 schematically shows a first embodiment of a spectacle lens with a Fresnel structure, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones. Fig. Figure 3 schematically shows a second embodiment of a spectacle lens with a Fresnel structure, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones. Fig. Figure 4 schematically shows a third embodiment of a spectacle lens with a Fresnel structure, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones. Fig. Figure 5 schematically shows a fourth embodiment of a spectacle lens with a Fresnel structure, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones. Fig. Figure 6 schematically shows a fifth embodiment of a spectacle lens with a Fresnel structure, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones. Fig. Figure 7 schematically shows a sixth embodiment of a spectacle lens with a Fresnel structure, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones. Fig. Figure 8 schematically shows a seventh embodiment of a spectacle lens with a Fresnel structure, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones. Fig. Figure 9 schematically shows an eighth embodiment of a spectacle lens with a Fresnel structure, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones. Fig. Figure 10 shows an exemplary embodiment of a computer-implemented method for the design of a spectacle lens with a Fresnel structure whose focusing effect is based on a gradient of the refractive index within the Fresnel zones, using a flowchart. Fig. Figure 11 shows a schematic representation of a pair of glasses with lenses having a Fresnel structure, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones.

[0053] The following refers to Fig. 1. The basic structure of a Fresnel lens, in which the focusing effect is based on a gradient in the refractive index within the Fresnel zones, is described before referring to the Fig. Two to nine different embodiments of a spectacle lens with a Fresnel structure are described, the focusing effect of which is based on a gradient of the refractive index within the Fresnel zones. The focusing effect can be positive or negative. Furthermore, it can include a spherical effect and / or an astigmatic effect.

[0054] Fig. Figure 1 schematically shows an example of a spectacle lens 1 with a Fresnel structure 3, comprising six Fresnel zones 3-1 to 3-6, in which the focusing effect is based on a gradient in the refractive index within the Fresnel zones 3-1 to 3-6. These gradients in the refractive index are symbolized by the point densities within the individual Fresnel zones 3-1 to 3-6, with a higher point density symbolizing a higher refractive index. It can be seen that, in this example, the refractive index in each Fresnel zone 3-1 to 3-6 increases from the radial center to the radial center.

[0055] The example lens 1 shown is a rimless round lens with a diameter of 40 mm. It should be noted, however, that the diameter of rimless round lenses can also be larger or smaller than 40 mm and is typically between 30 and 60 mm. The central Fresnel zone 3-1 has a diameter of 12.6 mm in this example. The widths of the annular Fresnel zones 3-2 to 3-6, which adjoin the central Fresnel zone 3-1, decrease progressively towards the outside, with the outermost Fresnel zone 3-6 having a width of 1 mm in this example.

[0056] Due to the decreasing width of the Fresnel zones, the gradient in the refractive index becomes increasingly steep from the central Fresnel zone 3-1 to the outer Fresnel zone 3-6. However, it would also be possible to make the gradient in the refractive index less steep in the outer Fresnel zones and instead design the surface of the Fresnel zones to be curved and / or inclined, so that the focusing effect of the Fresnel zones is determined partly by the gradient in the refractive index and partly by the shape of the surface of the Fresnel zones.

[0057] The local beam deflection achieved by the Fresnel structure 1 is determined by the gradient in the refractive index of the individual Fresnel zones 3-1 to 3-6 and the thickness of the lens 1. With a thickness of, for example, 1 mm and a maximum refractive index difference of 0.1 within a Fresnel zone, path length differences of 100 µm can be achieved in the Fresnel structure. A lens with a focusing power of 5 diopters thus has a diameter of the central Fresnel zone of 12.6 mm; at a distance of 20 mm from the lens center, the structure size is 1 mm, which is still acceptable for image quality in terms of effective pupil diameter.

[0058] In the approximation of perpendicular passage of the light rays through the spectacle lens 1, the path length difference ΔOPD (OPD: optical path difference) introduced by a spectacle lens with local thickness d(x,y) is given by the equation ΔOPD=(n(x,y)−1)⋅d(x,y) Given, where n(x,y) denotes the refractive index at position (x,y). The y-direction of the in Fig. The coordinate system shown in Figure 1 is perpendicular to the plane of the sheet, pointing away from the viewer. Within the limits of the refractive index n possible in materials with refractive index gradients. min and n max and, if applicable, a specified minimum and maximum thickness d min and d maxStarting from a predefined target path length difference (target OPD), which, for example, for a focusing lens, increases or decreases approximately quadratically with distance from the axis, a sectionwise continuous varying path length difference can be realized for spectacle lens 1. The discontinuities in the refractive index preferably occur from the maximum to the minimum refractive index to reduce the number of discontinuities. Discontinuities in the surface are also permitted, but not mandatory. For example, a continuous surface can be specified as a boundary condition. The distribution of the refractive index within spectacle lens 1 – including the discontinuities in the refractive index – can then be determined based on the predefined target OPD and / or on the predefined target imaging properties for the continuous surface.Alternatively, the locations of the jumps in the refractive index can be specified and the surface area determined accordingly, so that, for example, as much of the focusing effect as possible is realized via the gradient in the refractive index, in order to minimize, for example, the total thickness or mass of the element.

[0059] The described procedures can also be iterated, or the position of the jumps in the refractive index and / or the distribution of the refractive index and / or the surface shape can be optimized with a suitable objective function.

[0060] For optimization, a numerical model of the spectacle lens is typically defined with a specific initial position of the refractive index discontinuities and / or a specific initial refractive index distribution and / or an initial surface shape. Using this numerical model, the path length difference and / or the imaging properties to be achieved with the spectacle lens are then simulated via ray tracing. Subsequently, the deviation of the path length difference and / or the imaging properties determined by the simulation from the target path length difference and / or the target imaging properties are determined. The position of the refractive index discontinuities and / or the refractive index distribution and / or the surface shape in the numerical model of the spectacle lens are then...The parameters are then iteratively varied until the deviation of the path length difference determined by the simulation from the target path length difference and / or the mapping properties determined by the simulation from the target mapping properties fulfills a termination criterion. This termination criterion could be, for example, that the value of an objective function dependent on the deviation no longer exceeds a predefined limit, or the fact that the value of the objective function no longer changes significantly in the iteration steps.

[0061] In an optimized spectacle lens, the distribution of the refractive index discontinuities does not need to be uniform (e.g., concentric for a rotationally symmetric optic). Furthermore, the refractive index discontinuities do not need to be between minimum values. min and the maximum value n maxThe refractive index should be adjusted if this is advantageous for the imaging properties or aesthetics. For example, for spectacles with astigmatism, the contour lines could still be chosen to be concentric for aesthetic reasons (then with a different distribution of the refractive index at different azimuths). This offers advantages in terms of aesthetic appearance, especially in cases of oblique astigmatism or when there is different astigmatism in each eye.

[0062] For non-perpendicular passage of rays through the spectacle lens 1, an analogous consideration or optimization is possible.

[0063] A first exemplary embodiment of a spectacle lens 1 designed according to the invention is described below with reference to Fig. 2 described. In the spectacle lens 1 made of Fig. 2. Interfaces 5a to 5e are present where a high refractive index of a Fresnel zone and a low refractive index of an adjacent Fresnel zone meet. Interfaces 5a to 5e each have a section line 4a to 4e with the rear surface of the spectacle lens 11 and a section line 6a to 6e with the front surface of the spectacle lens 13. The figure shows a section through the spectacle lens 1, which extends in the x-direction of the Fig. The line extending from the coordinate system shown in Figure 2 runs along the line, with the origin of the coordinate system located at the geometric centroid VS of the front surface area of ​​the spectacle lens front surface 11 enclosed by the front section line 6a. The axes are in Fig. 2 is shown above the front surface of the spectacle lens 11 for the sake of clarity only.

[0064] In this exemplary embodiment, the x-direction of the coordinate system corresponds to an azimuth angle of 0 degrees, where the azimuth angle represents the angle that a straight line running clockwise in the xy-plane makes with the x-axis. The x-axis thus serves as a reference line for determining the azimuth angle. The y-direction of the coordinate system runs along the xy-axis. Fig. 1. Coordinate system shown perpendicular to the plane of the sheet, away from the viewer.

[0065] In the Fig. In the spectacle lens 1 shown in Figure 2, the front surface 13 and the back surface 11 of the spectacle lens are both parallel to the xy-plane. The azimuth angle can therefore be directly determined using a straight line running along the front surface 13, from the geometric centroid VS of the front surface area to a point on one of the front section lines 6a to 6e. The point to which this straight line leads then has the same azimuth angle as the straight line itself. Similarly, an azimuth angle can be determined for the line running from the geometric centroid RS of the back surface area to a point on one of the back section lines 4a to 4e, as well as for the point on one of the back section lines 4a to 4e that this straight line connects to the geometric centroid RS of the back surface area.

[0066] If the spectacle lens is different than in Fig. 2, which has a curvature, the azimuth angle of a connecting line running on the front surface 13 of the spectacle lens, which connects the geometric centroid VS of the front surface area with a point on a front section line 6a to 6e by the shortest path, is equal to the azimuth angle between the projection of this connecting line onto a tangent plane that is tangent to the geometric centroid VS of the front surface area enclosed by the front section line 6a and the x-axis running in the tangent plane, the projection being made along the normal direction of the tangent plane.Accordingly, the azimuth angle of a connecting line running on the posterior surface 11 of the spectacle lens, which connects the geometric centroid RS of the posterior surface area with a point on a posterior section line 4a to 4e via the shortest path, is the azimuth angle between the projection of this connecting line onto the aforementioned tangent plane and the x-axis running in the tangent plane, the projection being made along the normal direction of the tangent plane. Alternatively, instead of a projection onto a tangent plane running tangentially to the geometric centroid VS of the anterior surface area, a projection onto a tangent plane running tangentially to the geometric centroid RS of the posterior surface area can also be used, the projection being made along the normal direction of the tangent plane.

[0067] In the Fig. In the section shown along a line with an azimuth angle of 0 degrees, the radially innermost interface 5a, i.e., the interface between the high refractive index of Fresnel zone 3-1 and the lower refractive index of Fresnel zone 3-2, is represented by two straight lines. These straight lines are aligned such that light rays 9-1 traveling along these lines inside the lens 1 converge outside the lens's back surface at the pupil center PM of the wearer's eye 7 when the glasses are worn in their intended position. The term "intended position" refers to the position and orientation of the glasses relative to the wearer's eyes and face while the glasses are being worn (see DIN EN ISO 13666:2019-12, section 3.2.36).

[0068] The remaining boundary surfaces 5b to 5e are in the in Fig. The section shown in Figure 2 is each represented by two straight lines, which are aligned such that light rays 9-2 to 9-5 running along these lines inside the lens 1 converge outside the lens's back surface at the eye rotation point AD of the wearer's eye 7. The inclination of the lines representing the interfaces 5a to 5e significantly reduces shadowing and reflections for the wearer. In the section shown in Fig. In the exemplary embodiment shown in Figure 2, the interfaces 5b to 5e are particularly well adapted to the rolling eye when looking through an edge region of the spectacle lens 1. Only for the central Fresnel zone 3-1 is the interface 5a to the second Fresnel zone 3-2 adapted to the static eye in the zero gaze direction.

[0069] It should be noted that it is not necessary for the radially innermost interface 5a to be oriented such that light rays 9-1 traveling along it outside the lens 1 are directed towards the center of the pupil, whereas the remaining interfaces 5b to 5e are oriented such that light rays 9-2 to 9-5 traveling along these interfaces outside the lens 1 are directed towards the eye's center of rotation AP. Rather, it is also possible to orient all interfaces 5a to 5e either such that light rays traveling along the interfaces outside the lens 1 are directed towards the center of the pupil PM or towards the eye's center of rotation AD.It is also possible to orient several interfaces such that light rays running along these interfaces outside the spectacle lens 1 are directed towards the pupil center PM, and to orient several other interfaces such that light rays running along these other interfaces outside the spectacle lens 1 are directed towards the eye rotation center AD, for example, the light rays 9-1 and 9-2 running along interfaces 5a and 5b towards the pupil center PM and the light rays 9-3 to 9-5 running along interfaces 5c to 5e towards the eye rotation center AD.Furthermore, it is possible to orient the interface 5a such that light rays 9-1 passing along it outside the spectacle lens 1 are directed towards the pill center PM, and to orient the interface 5e such that light rays 9-5 passing along it outside the spectacle lens 1 are directed towards the eye rotation center AD, whereas the remaining interfaces 5b to 5d are oriented such that light rays 9-1 passing along these interfaces outside the spectacle lens 1 are directed towards one or more points located in the Fig. The zero gaze direction shown in Figure 2 lies on a straight line 8 passing through the pupil center PM and the eye rotation center AD between the pupil center PM and the eye rotation center AD. The interfaces 5b to 5d can be oriented, for example, such that light rays 9-2 to 9-4 running along these interfaces outside the spectacle lens 1 are directed to the same point or to different points, such that the points towards which the light rays 9-2 to 9-4 running along the interfaces 5b to 5d outside the spectacle lens 1 are directed are closer to the eye rotation center AD the further radially outwards the corresponding interface is located in the spectacle lens 1.

[0070] As the light rays exit the lens 1, their orientation changes due to refraction as they pass through the lens's back surface 11, so that the rays outside the lens 1 form an angle with the rays inside the lens 1. Since the refractive index of the lens 1 is always greater than 1 (the refractive index of air) and is typically in the range of 1.50 to 1.75, the rays exiting the lens's back surface form a larger angle with the normal than they did inside the lens.Since a low refractive index and a high refractive index border each other at the interface between the Fresnel zones, with the difference between the low and high refractive indices generally not exceeding 10%, the refractive index of the spectacle lens can be either the high refractive index, the low refractive index, or any refractive index between the high and low refractive indices. This intermediate refractive index can, in particular (but does not necessarily have to), be the average of the two. The resulting differences in the distance of the point where the rays converge from the back surface of the spectacle lens, caused by the different refractive indices, do indeed lead to the pupil center being...The eye rotation point may not be precisely hit, however this only slightly restricts the usability of the spectacle lens.

[0071] The alignment of the lines representing the interfaces 5a to 5e in a section through the spectacle lens 1 can be determined by the same point, regardless of the azimuth angle of the section. In this case, the rays emanating from a posterior section surface 4a to 4e each represent the lateral surface of a cone whose apex lies at the pupil center PM or the eye's center of rotation AD. However, the rays do not necessarily have to represent the lateral surfaces of cones. For example, the alignment of the lines representing the interfaces 5a to 5e can change with the azimuth angle in the direction of the section. This allows, for example, for...It is taken into account that the eye rolls more horizontally than vertically, for example by aligning the lines representing the boundary surfaces 5a to 5e in a section whose azimuth corresponds to the horizontally rolling eye 7 of the spectacle wearer such that light rays 9-1 to 9-5 running along these lines inside the spectacle lens 1 intersect outside the spectacle lens back surface 11 at the eye's center of rotation AD, whereas in a section whose azimuth corresponds to the vertically rolling eye 7 of the spectacle wearer the lines are oriented such that light rays 9-1 to 9-5 running along these lines inside the spectacle lens 1 intersect outside the spectacle lens back surface 11 at the pupil center PM.In sections whose azimuthal orientation lies between these two azimuthal orientations, the lines representing the interfaces 5a to 5e can be aligned such that light rays 9-1 to 9-5 running along these lines inside the spectacle lens 1 intersect outside the spectacle lens back surface at a point located between the eye rotation center AD and the pupil center PM.

[0072] Due to the described orientations of the interfaces 5a to 5e, each interface 5a to 5e has a section line 4a to 4e with the spectacle lens back surface 11, which has a smaller distance from the geometric centroid RS of the back surface area RB of the spectacle lens back surface 11 enclosed by the innermost back section line 4a than the distance that the front section line 6a to 6e of this interface 5a to 5e with the spectacle lens front surface 13 has from the geometric centroid VS of the front surface area VB of the spectacle lens front surface 13 enclosed by the innermost front section line 6a.The geometric centroid RS of the posterior surface area enclosed by the innermost posterior section line 4a is hereinafter referred to as the posterior geometric centroid RS, and the geometric centroid VS of the posterior surface area enclosed by the innermost anterior section line 6a is referred to as the anterior geometric centroid VS. In the present exemplary embodiment, each interface 5a to 5e has a section line 4a to 4e with the posterior lens surface 11, which, for any arbitrarily specified azimuth angle, is a smaller distance from the posterior geometric centroid RS than the distance that the section line 6a to 6e of this interface 5a to 5e with the anterior lens surface 13 has from the anterior geometric centroid VS.In alternative embodiments, each interface 5a to 5e can have a section line 4a to 4e with the posterior lens surface 11, which, for only a portion of all azimuth angles, is located at a smaller distance from the posterior geometric centroid RS than the distance that the section line 6a to 6e of this interface 5a to 5e with the anterior lens surface 13 has from the anterior geometric centroid VS. This portion of all azimuth angles comprises at least 25% of all azimuth angles, preferably at least 50% of all azimuth angles, and particularly at least 90% of all azimuth angles.

[0073] To further reduce shadowing and reflections, it is possible to arrange reflection-reducing layers at the interfaces in addition to the inclination of the interfaces 5a to 5e.

[0074] The interfaces 5a to 5e between a high refractive index of a Fresnel zone and a lower refractive index of an adjacent Fresnel zone need not necessarily be represented by straight lines in an azimuthal section, as is the case in the first exemplary embodiment. Instead, they can be curved in such a way that they follow the path of a light ray emanating from the pupil center PM, the eye rotation center AD, or an intermediate point. In this case as well, each interface 5a to 5e has a section line 4a to 4e with the posterior lens surface 11, which is located a shorter distance from the posterior geometric centroid RS than the distance that the section line 6a to 6e of these interfaces 5a to 5e with the anterior lens surface 13 has from the anterior geometric centroid VS. A corresponding second exemplary embodiment is shown in Fig. 3 shown.

[0075] The Fig. Figure 3 shows, by way of example, the interface 5a between the high refractive index of the central Fresnel zone 3-1 and the adjacent Fresnel zone 3-2 in a section along an azimuthally oriented line. The figure also shows a light ray 9 originating from the pupil center PM and entering the spectacle lens 1 through the lens back surface 11 at the interface 5a between the high and lower refractive indices. Due to the gradient in refractive index, the light ray 9 has a curved path inside the spectacle lens 1. In the Fig. In the exemplary embodiment shown in Figure 3, the line representing the interface 5a exhibits a curvature in each section along an azimuthal line, which is adapted to the path of the light beam 9. This measure helps to further reduce shadowing and reflections.

[0076] The different refractive indices to the left and right of an interface 5 also cause a light ray 9 entering the lens 1 through the rear surface 11 at interface 5a to be deflected slightly differently, depending on whether it enters the lens 1 immediately to the left or immediately to the right of interface 5a. Therefore, depending on whether it enters the lens 1 immediately to the left or immediately to the right of interface 5a, it exits the lens 1 through the front surface 13 at different points, as shown in Fig. As shown in Figure 4 using light rays 9a and 9b, if we consider a set of light rays that, in this exemplary embodiment, originate from the pupil center PM and enter the region of the Fresnel zone 3-1 with the high refractive index at the intersection line 4a immediately adjacent to the interface 5a, these light rays emerge from the spectacle lens 1 through the lens front surface 13 as light rays 9a. These light rays are subsequently referred to as first light rays. Similarly, if we consider a set of light rays that, in this exemplary embodiment, originate from the pupil center PM and enter the region of the Fresnel zone 3-2 with the low refractive index at the intersection line 4a immediately adjacent to the interface 5a, these light rays emerge from the spectacle lens 1 through the lens front surface 13 as light rays 9b.These light rays are hereinafter referred to as second light rays. In negative lenses, the distance between the first light rays 9a exiting along the interface 5a and the second light rays 9b exiting along the interface 5a results in an annular region 14 on the front surface 13 of the spectacle lens, from which no light rays emerge. The area within the spectacle lens 1 bounded by this annular region 14 and the path of the light rays 9a and 9b inside the lens 1 is referred to as a dead zone 15 within the scope of the present invention, since no ray emanating from the pupil center PM passes through this zone. Corresponding dead zones are formed at all interfaces 5a to 5b. Light entering these dead zones from the outside can cause reflections and scattered light. In a third exemplary embodiment, which is described in . Fig. As shown in Figure 4, to prevent reflections and scattered light, the annular area 14 on the front surface of the spectacle lens 13 is provided with a coating 17, which can be, in particular, a light-absorbing coating. Additionally or alternatively, the dead zones 15 can be provided with a different refractive index than the adjacent refractive indices. A different refractive index can be achieved, for example, by using a different material in the dead zones 15 or by doping the dead zones 15. Furthermore, additionally or alternatively, to prevent reflections and scattered light, the areas inside the spectacle lens 1 represented by the paths of rays 9a and 9b can be provided with anti-reflective layers. The anti-reflective layers can, in particular, be light-absorbing layers.

[0077] Although the interface 5a in Fig. 4 has a curvature adapted to the beam path inside the spectacle lens, alternatively, it is possible to provide an interface which in the sections along an azimuthal line is represented by a straight line extending from the entry point of the beam 9 located on the rear surface 11 of the spectacle lens to a point located in the annular area 14 of the front surface 13 of the spectacle lens.

[0078] The resolution of a Fresnel structure for ophthalmic applications is limited by the structure width, which should ideally be larger than a certain fraction of the pupil, for example, larger than 0.5 mm, and particularly larger than 1 mm. With a strong focusing effect, this leads to thick Fresnel structures in the case of Fresnel structures based on a gradient in the refractive index, and to large jumps in the arrow height in the case of Fresnel structures based on a curvature and / or inclination of the surface. In a fourth exemplary embodiment, which is described in Fig. As shown in Figure 5, the spectacle lens 1 has a combined Fresnel structure comprising a first Fresnel structure 3 based on a gradient in the refractive index and a second Fresnel structure 19 based on Fresnel facets 20-1 to 20-6, i.e., a Fresnel structure in which the focusing effect is based on a curvature and / or inclination of the surface of the Fresnel facets. The combination of the two Fresnel structures allows both the thickness of the spectacle lens 1 and the maximum sag h of the Fresnel facets 20-1 to 20-6, and the associated jumps in sag, to be kept relatively small. It is advantageous if, as in the present exemplary embodiment, the interfaces 5a to 5e coincide spatially with the back faces 21a to 21f of the Fresnel facets 20-1 to 20-6. However, this is not absolutely necessary within the scope of the invention.

[0079] In the Fig. In the exemplary embodiment shown in Figure 5, the gradients in the refractive index are limited to the portion of the combined Fresnel structure shown in the figure above; that is, they do not extend into the Fresnel facets 20-1 to 20-6. In alternative embodiments, however, the gradients can extend into the Fresnel facets 20-1 to 20-6. In this case, however, the curvatures of the surfaces of the Fresnel facets 20-1 to 20-6 differ from the curvature of the surfaces of Fresnel facets into which the gradients in the refractive index do not extend. Additionally or alternatively, in further embodiments, the back faces 21a to 21e of the Fresnel facets 20-1 to 20-5 can have the same orientation as the interfaces 5a to 5e. Furthermore, the spectacle lens 1 of the fourth exemplary embodiment does not differ from the spectacle lens of the first exemplary embodiment.

[0080] A fifth exemplary embodiment of a spectacle lens 1 according to the invention is shown in Fig. 6 shown. Elements whose function does not differ from elements in the preceding exemplary embodiments are shown in Fig. 6, which are designated with the same reference numerals as in the preceding exemplary embodiments, and are not explained again in detail.

[0081] The spectacle lens 1 of the in Fig. The fifth exemplary embodiment shown in section 6 differs from the one in Fig. The spectacle lens of the first exemplary embodiment shown in Figure 2 is made thicker by having a concave curvature on its front surface 13. This offers the advantage that in the edge region, where a greater deflection of the light rays is required to achieve the focusing effect, the spectacle lens 1 is thicker, thus allowing for a greater structure width of the Fresnel structure 3 based on the gradient in the refractive index. Instead of the Fig. In addition to the concave curvature shown in Figure 6, the front surface 13 of the spectacle lens can alternatively have a convex curvature. Furthermore, the back surface 11 of the spectacle lens can also have a concave or convex curvature, either instead of or in addition to the front surface 13. The combination of a concave or convex curvature of the front surface 13 and / or a concave or convex curvature of the back surface 11 with a Fresnel structure 3 based on a gradient in the refractive index generally offers the possibility of decoupling the surface geometry of the spectacle lens 1 from the focusing effect to be achieved. Otherwise, the spectacle lens 1 of the fifth exemplary embodiment does not differ from the spectacle lens of the first exemplary embodiment.

[0082] A sixth exemplary embodiment of the spectacle lens 1 according to the invention is shown in Fig. 7 shown. Elements whose function does not differ from elements in the preceding exemplary embodiments are shown in Fig. 7, which are designated with the same reference numerals as in the preceding exemplary embodiments, and are not explained again in detail.

[0083] In contrast, in Fig. In the first exemplary embodiment shown in 2, the front surface of the spectacle lens 13 has, according to the Fig. In the sixth exemplary embodiment shown in Figure 7, facets are formed by the fact that the lens front surface 13 has curved surface sections 13-1 to 13-6 in the region of the respective Fresnel zone 3-1 to 3-6. The lens front surface 13 itself is continuous, but at the boundaries between the individual Fresnel zones 3-1 to 3-6, there are kinks 18a to 18e in the lens front surface 13, so that the first derivative of the lens front surface 13 is not continuous. This design offers the possibility that the gradients in the refractive index within the respective Fresnel zone 3-1 to 3-6 can increase linearly. Linear increases in the refractive index are generally easier to produce than gradients in the refractive index that follow a nonlinear function, for example, a spherical, parabolic, or hyperbolic function.In the case of linear gradients, the beam deflection required for the focusing effect is achieved by the gradients in the refractive index, while the shape of the wavefront is determined by the curvatures of the lens front surface 13 in surface sections 13-1 to 13-6. Because the kinks 18a to 18e in the lens front surface 13 coincide with the changes in the refractive index, such a lens 1 can be produced without any interfering optical properties. Instead of the one in . Fig. The front surface of the lens 13 can alternatively have convex facets instead of the concave facets shown in Figure 7. Furthermore, the back surface of the lens 11 can also have concave or convex facets instead of, or in addition to, the front surface of the lens 13.

[0084] A seventh exemplary embodiment of the spectacle lens according to the invention is shown in Fig. 8. Elements whose function does not differ from elements in the preceding exemplary embodiments are shown in Fig. 8, which are designated with the same reference numerals as in the preceding exemplary embodiments, are not explained again in detail.

[0085] In the Fig. In the exemplary embodiment shown in Figure 8, the spectacle lens 1 has a central area 23 without a gradient in the refractive index. In this area, the focusing effect of the spectacle lens 1 is achieved solely by the curved shape of the lens front surface 13. Adjoining this central area 23 without a gradient in the refractive index are Fresnel zones 3-2 to 3-6, as described with reference to the spectacle lens 1 of the first exemplary embodiment. The focusing effect of the Fig. The Fresnel structure 3 of the spectacle lens 1 shown in Figure 8 is therefore created outside the central region 23 by a gradient in the refractive index. In contrast to the preceding exemplary embodiments, the first interface 5a is not an interface where a low refractive index and a high refractive index meet, but rather an interface between a region without a gradient in the refractive index (namely the central region 23) and a region with a gradient in the refractive index (namely the first Fresnel zone 3-2). With the Fig. With the spectacle lens 1 shown in Figure 8, a good compromise between thickness / weight on the one hand and image quality of the spectacle lens 1 on the other hand can be achieved, without distortions of the image occurring in the edge area, as would otherwise be common with surface shapes of this type.

[0086] The in Fig. The spectacle lens 1 shown in Figure 8 represents a positive lens, which has its greatest thickness in the center of the spectacle lens 1 and a planar geometry in its edge region. In contrast, with negative lenses, the thickness increases from the central part 23 of the spectacle lens 1 and can decrease again towards the edge of the spectacle lens 1, as can be seen from an eighth embodiment of the spectacle lens 1 according to the invention, which is designed as a negative lens. Fig. 9 is shown. Except for the shape of its lens front surface 13, it differs in Fig. 9 spectacle lens shown from the one in Fig. The spectacle lens shown in section 8 is also characterized by the fact that the gradient in the refractive index is designed to increase from radially inward to radially outward, whereas in the spectacle lens it is... Fig. 8 is designed such that it decreases from radially inward to radially outward. Furthermore, the differ in Fig. 8 and in Fig. The 9 depicted spectacle lenses are not separate.

[0087] The gradient of the refractive index in the spectacle lenses according to exemplary embodiments 2 to 6 and 8 is selected such that the refractive index increases from the radial center to the radial center. Therefore, the spectacle lenses of embodiments 2 to 6 and 8 represent negative lenses. However, the spectacle lenses of embodiments 2 to 6 and 8 can also be designed as positive lenses if the gradient of the refractive index is selected such that the refractive index decreases from the radial center to the radial center. Due to the Fresnel structure based on a gradient in the refractive index, it is possible to decouple the surface shape of the spectacle lens from its focusing effect, so that a specific focusing effect can be achieved with different combinations of surface shapes and gradients in the refractive index. This considerably expands the design possibilities for spectacle lenses.

[0088] In the spectacle lenses according to the invention, chromatic aberrations of the Fresnel structures based on the gradient in the refractive index can be minimized or completely avoided by suitable combinations of two or more materials. This is described, for example, in Buczinsky et al., “Achromatic nanostructured gradient index microlenses”, Opt. Exp. 27 (2019), pp. 9588–9599 and the references cited therein. The classic analogue to this is an achromatic doublet in which the refractive index is (conceptually) averaged along the optical axis. For a planar Fresnel structure based on a gradient in the refractive index, materials must be selected in this analogy in which the desired refractive power of a doublet with planar surfaces on both sides can be achieved. This is possible in principle with a neo-achromat (low dispersion with a high refractive index or high dispersion with a low refractive index).However, the case of a doublet lens is also interesting, as it requires a certain curvature of a surface for color correction. Applied to a Fresnel structure based on a gradient in the refractive index, this means that a certain basic curvature of the front surface and / or the back surface of the spectacle lens, as described in... Fig. 6 is shown, or a faceting of the front surface and / or the back surface of the spectacle lens, as shown in Fig. Figure 7 is shown, which is necessary to achieve the desired color correction.

[0089] The following refers to Fig. Section 10 describes an exemplary embodiment of a computer-implemented method for designing a spectacle lens according to the invention, illustrated by a flowchart. The method is executed on a computer in which a computer program containing instructions for carrying out the method is stored in memory. Based on these instructions, the computer's processor then executes the computer-implemented method. For example, a non-volatile, computer-readable storage medium on which the computer program is stored can be used to read the computer program into memory. Alternatively, the computer program can also be retrieved from a computer system via a network.

[0090] In the first step S1 of the procedure, the required user-specific data is read into the computer. The user-specific data includes at least correction data representing the correction to be achieved with the spectacle lens, as well as distance data representing at least the distance of the pupil center and / or the eye's center of rotation from the vertex of the spectacle lens's back surface, or from which at least the distance of the pupil center and / or the eye's center of rotation from the vertex of the spectacle lens's back surface can be derived.

[0091] The correction data can specify the correction to be achieved with the spectacle lens, for example, as a single spherical vertex power for near or distance vision if the spectacle lens is to be a single-vision lens. Alternatively, they can also specify the correction to be achieved as multiple spherical vertex powers if the spectacle lens is to be a multifocal lens, such as a progressive lens. In the case of a progressive lens, the spherical vertex power for near vision can be specified as an addition to the spherical vertex power for distance vision, according to DIN EN ISO 13666:2019-12, section 3.16.3. If the correction to be achieved with the spectacle lens is also intended to correct astigmatism, the correction data can specify at least one astigmatic vertex power in addition to at least one spherical vertex power.

[0092] Optionally, the user-specific data can also include data indicating the usage position of the spectacle lens (DIN EN ISO 13666:2019-12, section 3.2.36). This data can include, in particular, the pantoscopic tilt angle (DIN EN ISO 13666:2019-12, section 3.2.37), the lens-to-frame angle (DIN EN ISO 13666:2019-12, section 3.2.8), and the vertex distance (DIN EN ISO 13666:2019-12, section 3.2.40).

[0093] The user-specific data can be individualized for the respective user, or it can be general data that has been determined from a statistical ensemble of users.

[0094] In a second step, S2 is used to determine the locally required beam deflection based on the recorded data, whereby in the case of a multifocal spectacle lens or a progressive lens an object distance model is also used, which specifies the object distance for which the spectacle lens is to be optimized for the respective direction of gaze.

[0095] In the next step, S3, a surface shape of the spectacle lens is specified. If the spectacle lens is to have a central area without gradients in the refractive index, as is the case with regard to the Fig. 8 and Fig. As described in section 9, step S3 can also include optimizing the surface shape in the central area with regard to the beam deflection to be achieved, so that the surface shape specified in step S3 in the central area is already optimized with regard to the focusing effect.

[0096] In step S4, the gradients of the refractive index and / or the locations of the jumps in the refractive index are then optimized, as is done with reference to Fig. 1 has been described. Furthermore, as part of the optimization carried out in step S4, the inclination of the interfaces between the Fresnel zones or the course of these interfaces is determined, whereby the point from which a ray travels to the respective interface is determined based on the distance data. In the case of cone-shaped interfaces, such as those with reference to Fig. As described in section 2, the inclination of the respective interface can be determined based on the geometric relationships resulting from the lens's position in use and the distance data. In the case of curved interfaces, as described in section 2, the inclination of the respective interface can be determined based on the geometric relationships resulting from the lens's position in use and the distance data. Fig. 3 and Fig. As described in section 4, the course of this interface is determined using ray tracing performed as part of the optimization.

[0097] If the central area is not to have a gradient in the refractive index and a surface shape has already been optimized in step S3 with regard to the focusing effect, then in step S4 only the edge area of ​​the spectacle lens adjoining the central area needs to be optimized.

[0098] In an alternative embodiment of the method, instead of specifying the surface shape, the locations of the discontinuities in the refractive index can be defined, and then the surface shape and the gradients of the refractive index can be optimized. As a further alternative, it is also possible to optimize the surface shape, the locations of the discontinuities in the refractive index, and the gradients of the refractive index simultaneously.

[0099] At the end of the process, the optimized lens is output by the computer in step S5 as a numerical representation of the lens. Based on this numerical representation, a computer-controlled manufacturing machine can then be controlled to produce a physical lens, for example, using an additive manufacturing process. The computer-controlled manufacturing machine could be a 3D printer that prints a lens corresponding to the numerical representation of the lens. The gradients in the refractive index can be achieved by varying the material feed depending on the current position of the print head. A continuous variation in the refractive index can be achieved by appropriately mixing two materials.

[0100] A pair of glasses 30, which is equipped with at least one spectacle lens 1 according to the invention, is schematically shown in Fig. 11 shown. The representation in Fig. Figure 11 is essentially limited to the right spectacle lens 1L and the right spectacle temple 33. The left spectacle lens 1L is only partially shown, and the left spectacle temple is not shown at all.

[0101] The in Fig. The glasses 30 shown in Figure 11 are designed as AR glasses (AR: Augmented Reality) with which images superimposed on the surroundings can be presented to the wearer. A light guide 31 is associated with the right lens 1R, extending in this exemplary embodiment from the right edge of the lens 1R to approximately the middle of the lens 1R. The light guide 31 is arranged with an air gap 32 to the lens 1R, so that a beam of light can be guided through the interior of the light guide 31 by means of total internal reflection. Instead of an air gap 32 between the lens 1R and the light guide 31, an intermediate layer can also be present whose refractive index is lower than that of the material from which the light guide 31 is made. Such an intermediate layer offers the advantage over an air gap that it can simultaneously serve as an attachment point for the light guide 31 to the lens 30.The intermediate layer can, for example, be formed by an optical kit. Alternatively, the production of the intermediate layer can be integrated into the 3D printing process of the spectacle lens by first printing a suitable low-refractive-index material as a layer before the spectacle lens 1R is manufactured. The low-refractive-index material of the intermediate layer can, for example, be printed onto the light guide 31 before the spectacle lens is printed onto the intermediate layer. Furthermore, additional layers for further functions can be applied in a final outer layer of the spectacle lens 1R, for example, to integrate scratch protection or tints.

[0102] A display 34, such as an LED display, an LCD display, an OLED display, etc., is located in the area of ​​the temple 33. A control device 35 for controlling the display 34 is also located in the area of ​​the temple 33. The control device 35 controls the display 34 such that images intended to be superimposed on the wearer's field of vision are displayed on the display 34. The control device 35 can generate the images to be displayed on the display 34 itself or receive them via cable or, preferably, wirelessly from another device (not shown). A beam of light emanating from the display 34, representing the image to be displayed, is coupled into the light guide 31 via a coupling element 36 located at the right edge of the light guide 31. In the present exemplary embodiment, the coupling element 36 is designed as a prism.The prism surfaces of prism 36 are designed such that a beam of light emanating from the display 34 is coupled into the optical fiber 31 at an angle across its circumferential surface towards an outer surface. This angle causes the beam to be totally reflected by the outer surface, resulting in total internal reflection upon impact with the opposite outer surface of the optical fiber 31. In this way, the beam can be guided via total internal reflection from the coupling element 36 to an output coupling structure 37, which couples the beam out of the optical fiber 31 towards the eye. It should be noted that the guidance of the beam within the optical fiber does not necessarily have to occur via total internal reflection.Instead, the outer surfaces of the light guide can be provided with semi-transparent reflective coatings that allow ambient light to pass through the light guide 31 and simultaneously guide the beam coupled in via the coupling element 36 at least partially to the output coupling structure 37 by means of reflections.

[0103] In the present embodiment, the surfaces of the prism 36 also have an imaging function that creates the impression for the user of the glasses that the image displayed on the screen 34 is floating at a certain distance in front of the eye in the surrounding environment. This imaging function can alternatively be performed completely or partially by one or more other structures, e.g., an imaging optic (not shown) arranged between the screen 34 and the prism 36.

[0104] In the present exemplary embodiment, the output coupling structure 37 is designed in the form of semi-transparent Fresnel elements, so that in addition to the image projected into the wearer's field of vision, the surroundings can also be perceived. It can also be designed as a semi-transparent, inclined mirror. Alternatively, the output coupling structure 37 can be designed as a diffraction grating. In this case, the beam of light is coupled out of the optical fiber 31, for example, via the first-order diffraction maximum, while the observation light can pass through the output coupling structure 31 with minimal interference via the zero-order diffraction maximum. Furthermore, the output coupling structure 37 can also be designed to contribute to the imaging process, for example, by providing the semi-transparent Fresnel elements with a suitable curvature.

[0105] Because the Fresnel structure of the spectacle lens 1R of the spectacle 30 provides a focusing effect that is based, at least partially, but especially completely, on a gradient of the refractive index within the corresponding Fresnel zone in at least one, in particular in a majority of the Fresnel zones or in all Fresnel zones, the thickness of the spectacle lens 1R can be kept low, even if the spectacle lens 1R is designed to correct a high degree of refractive error. This allows the combination of the spectacle lens 1R with the light guide 31 to be realized with a relatively low thickness.

[0106] The one in Fig.The left spectacle lens 1L, shown only partially, can either be designed analogously to the right spectacle lens 1R, or it can be a spectacle lens without a light guide. Of course, it is also possible that the left spectacle lens 1L is equipped with a light guide and the right spectacle lens 1R is not.

[0107] The present invention has been described in detail with reference to exemplary embodiments for illustrative purposes. However, a person skilled in the art will recognize that the invention can deviate from the individual exemplary embodiments and, in particular, that features of the individual exemplary embodiments can also be combined with one another. Therefore, the present invention is not to be limited by the exemplary embodiments, but only by the attached claims. Reference symbol list 1 spectacle lens 3 Fresnel structure 3-1 - 3-6 Fresnel zones 4a-e Intersection line 5a-e Interfaces 6a-e Intersection line 7 Eye 8 Straight 9-1 - 9-5 Light rays 9, 9a, 9b Light rays 11 Lens back surface 13 Front surface of the spectacle lens 14 ring-shaped area 15 dead zone 17 Coating 18a-e kinks 19 Fresnel structure 20-1 - 20-6 Fresnel facets 21a-f Back edges 23 central area 30 spectacle lens 31 fiber optic cables 32 air gap 33 Eyeglass temples 34 ads 35 Control device 36 Coupling element 37 Coupling structure AD Eye rotation point PM Pupil center RS geometric center of gravity VS geometric center of gravity RB back surface area VB front surface area QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 0 927 905 A

[0004] GB 1,154,360 A

[0004] JP 2019174647 A

[0004] US 2013 / 0120707 A1

[0004] WO 2018 / 134037 A2

[0005] US 2022 / 0252931 A1

[0006] WO 97 / 10527 A1

[0009] Cited non-patent literature

[0000] Suhara et al., “Graded-index Fresnel lenses for integrated optics,” Appl. Opt. 21 (1982), pp. 1966-1971

[0007] P. Dellulier et al., „Femtosecond Laser Direct Writing of Gradient Index Fresnel Lens in GeS2-Based Chalcogenide Glass for Imaging Applications“, Appl. Sci 12 (2022), 4490

[0007] R. Buczynski et al. R 2019, ‚Achromatic nanostructured gradient index microlenses‘, Optics Express, vol. 27, no. 7, pp. 9588-9600

[0007] A. Zhang, „Multifocal diffractive lens design in ophthalmology“, Applied Optics, Vol. 59, No. 31 (1 November 2020), pp. 9807- 9823

[0008] DIN EN ISO 13666:2019-12 [0021, 0067, 0091, 0092] Buczinsky et al., „Achromatic nanostructured gradient index microlenses“, Opt. Exp. 27 (2019), pp. 9588-9599

[0088]

Claims

[1] Lens (1) with - a rear surface of the lens (11) facing the eye; - a front surface of the lens (13) which is to be turned away from the eye; - a Fresnel structure (3) comprising at least two Fresnel zones (3-1 to 3-6) providing a focusing effect, wherein the focusing effect of the Fresnel structure (3) in at least one of the Fresnel zones (3-1 to 3-6) is based at least partially on a gradient of the refractive index within, and the Fresnel structure (3) has interfaces (5a to 5e) at which a high refractive index of a Fresnel zone (3-1 to 3-6) and a low refractive index of an adjacent Fresnel zone (3-1 to 3-6) adjoin one another, wherein - the at least one boundary surface (5a to 5e) has a rear intersection line (4a to 4e) with the rear surface of the spectacle lens (11) and a front intersection line (6a to 6e) with the front surface of the spectacle lens (13); - the rear surface area of ​​the lens rear surface (11) enclosed by the innermost rear cutting line (4a) has a rear geometric center of gravity (RS) and - the front surface area of ​​the front surface of the spectacle lens (11) enclosed by the innermost front cutting line (6a) has a front geometric center of gravity (VS); characterized by , that - the rear section line (4a to 4e) has a smaller distance from the rear geometric centre of gravity (RS) than the front section line (6a to 6e) from the front geometric centre of gravity (VS) for at least 25% of the azimuth angles. [2] Spectacle lens (1) according to claim 1, characterized bythat at least one boundary surface (5a to 5e) is aligned such that those rays (9-1 to 9-5) which run within a cutting plane along this boundary surface (5a to 5e) unite, after exiting the rear surface of the spectacle lens (11), into a point (PM, AD) lying on the side of the rear surface of the spectacle lens (11) and spaced therefrom, wherein the cutting plane is a plane, - in which there is a front connecting line running at a specific azimuth angle in the front surface (13) of the lens, which connects the geometric center of gravity (VS) of the enclosed front surface area by the shortest route with a point on the front intersection line (6a to 6e) of one of the boundary surfaces (5a to 5e), - and in which there is also a rear connecting line running at the same specific azimuth angle in the rear surface of the lens (11), which connects the geometric center of gravity (RS) of the enclosed rear surface area by the shortest path with a point on one of the rear intersection lines (4a to 4e) of the same boundary surfaces (5a to 5e). [3] Spectacle lens (1) according to claim 2, characterized by that the point (PM, AD) lying on the side of the rear surface of the lens (11) and spaced therefrom is the same for all azimuth angles. [4] Spectacle lens (1) according to claim 2, characterized by that the distance of the point (PM, AD) lying on the side of the rear surface of the spectacle lens (11) and spaced therefrom from the rear surface of the spectacle lens (11) depends on the azimuth angle. [5] Spectacle lens (1) according to one of claims 2 to 4, characterized bythat at least two of the interfaces (5a to 5e) are aligned in such a way that, for the respective interface (5a to 5e), all rays (9-1 to 9-5) running within the cutting plane along this interface (5a to 5e) combine, after exiting the rear surface (11) of the spectacle lens, into a point (PM, AD) lying on the side of the rear surface (11) of the spectacle lens and spaced therefrom, and the point (PM, AD) lying on the side of the rear surface (11) of the spectacle lens and spaced therefrom is the same for the at least two interfaces (5a to 5e). [6] Spectacle lens (1) according to one of claims 2 to 5, characterized bythat at least two of the boundary surfaces (5a to 5e) are aligned in such a way that, for the respective boundary surface (5a to 5e), all rays (9-1 to 9-5) running within the cutting plane along this boundary surface (5a to 5e) converge, after exiting the rear surface of the spectacle lens (11), into a point (PM, AD) located on the side of the rear surface of the spectacle lens (11) and spaced therefrom, and the distance of the point (PM, AD) located on the side of the rear surface of the spectacle lens (11) and spaced therefrom from the rear surface of the spectacle lens (11) is different for the at least two boundary surfaces (5a to 5e). [7] Spectacle lens according to one of claims 2 to 6, characterized by that at least one of the interfaces (5a to 5e) runs along a straight line within the cutting plane. [8] Spectacle lens (1) according to one of claims 2 to 7, characterized bythat at least one of the boundary surfaces (5a to 5e) runs within the cutting plane along a curved line, the curvature of which - is a curvature that follows the path of a light beam (9a) that emanates from the point (PM, AD) spaced from the rear surface of the lens (13) and enters the spectacle lens (1) at the boundary between the high refractive index of one Fresnel zone (3-1 to 3-6) and the low refractive index of the adjacent Fresnel zone (3-1 to 3-6) through the rear surface of the lens (11) immediately adjacent to the boundary surface (5a to 5e) on the side of the high refractive index; or - is a curvature that follows the path of a light beam (9b) that emanates from the point (PM, AD) spaced from the rear surface of the lens (13) and enters the spectacle lens (1) at the boundary between the high refractive index of one Fresnel zone (3-1 to 3-6) and the low refractive index of the adjacent Fresnel zone (3-1 to 3-6) through the rear surface of the lens (11) immediately adjacent to the boundary surface (5a to 5e) on the side of the low refractive index; or - a curvature whose course lies between the courses of the said light rays (9a, 9b). [9] Spectacle lens (1) according to one of claims 2 to 8, characterized bythat the spectacle lens (1) is designed as a negative lens and has a dead zone (15) for each boundary surface (5a to 5e), which is delimited by the course of a set of first light rays (9a) in the spectacle lens (1), by the course of a set of second light rays (9b) in the spectacle lens (1) and by an annular region (14) of the front surface (13) of the spectacle lens resulting from the course of the first set of light rays (9a) and the course of the second set of light rays (9b), wherein - the first light rays (9a) are those light rays (9) which emanate from the point (PM, AD) spaced from the rear surface of the lens (11) and enter the Fresnel zone (3-1 to 3-6) with the high refractive index adjacent to the rear surface (5a to 5e) through the rear surface of the lens (11) immediately adjacent to the corresponding interface (5a to 5e), and - the second light rays (9b) are those light rays (9) which emanate from the point (PM, AD) spaced from the rear surface of the spectacle lens (11) and enter the Fresnel zone (3-1 to 3-6) with the low refractive index adjacent to the rear surface (5a to 5e) through the rear surface of the spectacle lens (11) immediately adjacent to the corresponding boundary surface (5a to 5e), and - the respective dead zones (15) are each provided with at least one light-absorbing layer (17). [10] Spectacle lens (1) according to claim 7 and claim 9, characterized by that at least one of the boundary surfaces (5a to 5e) runs along a straight line within the cutting plane and this straight line is aligned such that it runs at least partially within the dead zone (15). [11] Spectacle lens (1) according to claim 9 or claim 10, characterized bythat the dead zones (15) of the spectacle lens (1) have a different refractive index than the high refractive index and the low refractive index of the Fresnel zones (3-1 to 3-6) adjacent to the respective dead zone (15). [12] Spectacle lens (1) according to one of claims 1 to 11, characterized by that it has a central region (23) without a Fresnel structure (3) and with a curved surface and the Fresnel structure (3) is only present in a region outside the central region (23), wherein the spectacle lens (1) provides a focusing effect in the central region (23) due to the curved surface and in the edge region due to the Fresnel structure (3). [13] Spectacle lens (1) according to one of claims 1 to 12 characterized bythat an additional Fresnel structure (20) with Fresnel facets (20-1 to 20-6) having curved surfaces is formed on the front surface (13) of the spectacle lens or the rear surface (11) of the spectacle lens and has jumps in the arrow height at the front cutting lines (6a to 6e) or the rear cutting lines (6a to 6e). [14] Spectacle lens (1) according to claim 2 and claim 13, characterized by that the jumps in the sagittal heights are formed by flanks (21a to 21e) of the Fresnel facets (20-1 to 20-6), which continue the course of the interfaces (5a to 5e). [15] Spectacle lens (1) according to one of claims 1 to 14, characterized by that it has a spectacle lens front surface (13) and / or a spectacle lens rear surface (11) which has a bend (18a to 18e) at the boundaries between two Fresnel zones (3-1 to 3-6). [16] Spectacle lens (1) according to one of claims 1 to 15, characterized bythat at least two materials are combined in such a way that color errors are at least partially compensated. [17] Spectacle lens (1) according to one of claims 1 to 16, characterized by that at the high refractive index there is low dispersion and at the low refractive index there is high dispersion [18] Computer-implemented method for designing a spectacle lens according to one of claims 1 to 17, characterized by - detecting at least correction data representing the correction to be achieved with the spectacle lens (1) and distance data representing at least the distance of the pupil center (PM) or the eye rotation point (AD) from the vertex of the rear surface of the spectacle lens (11) or from which at least the distance of the pupil center (PM) or the eye rotation point (AD) from the vertex of the rear surface of the spectacle lens (11) can be derived; - Determining the Fresnel structure (3) on the basis of at least the correction data and the distance data. [19] Computer-implemented method according to claim 18, characterized by a step of detecting the corneal-vertex distance. [20] Computer-implemented method according to claim 18 or 19, characterized by a step of outputting a numerical representation of the designed spectacle lens (1) for use in producing an actual spectacle lens (1) corresponding to the numerical representation of the spectacle lens (1) by means of a computer-aided numerically controlled manufacturing process. [21] Non-volatile computer-readable storage medium with a numerical representation of a spectacle lens (1) according to one of claims 1 to 17 for use in the manufacture of an objective spectacle lens (1) corresponding to the numerical representation of the spectacle lens (1) by means of a computer-aided numerically controlled manufacturing process. [22] Computer system with data which can be called up via a network and which provides a numerical representation of a spectacle lens according to one of claims 1 to 17 for use in the manufacture of an objective spectacle lens corresponding to the numerical representation of the spectacle lens (1) by means of a computer-controlled manufacturing process. [23] A computer program comprising instructions which, when the instructions are executed by the computer, cause a computer to perform the computer-implemented method according to any one of claims 18 to 20. [24] A computer comprising a memory storing instructions for causing a computer to perform the computer-implemented method of any one of claims 18 to 20, and a processor for executing the instructions stored in the memory. [25] Method for producing a spectacle lens (1), in which an objective spectacle lens (1) corresponding to the numerical representation of the spectacle lens is produced by means of a computer-aided numerically controlled production process on the basis of a numerical representation of a spectacle lens (1) according to one of claims 1 to 17. [26] Spectacles (30) with at least one spectacle lens (1) according to one of claims 1 to 18. [27] Spectacles (30) according to claim 26, further comprising a display (34), a light guide (31), a coupling element (36) for coupling a beam of rays emanating from the display (34) into the light guide (31) and a coupling-out structure (37) for coupling the beam of rays out of the light guide (31) in the direction of the eye of a wearer of the spectacles (30). [28] Spectacles according to claim 27, in which an air gap (32) is present between the light guide (31) and the spectacle lens (1). [29] Spectacles according to claim 27, in which a layer is present between the light guide (31) and the spectacle lens (30) whose refractive index is lower than the refractive index of the light guide (31).

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