Myopia corrective lenses with a continuous effect distribution

Abstract

In particular, the invention relates to a spectacle lens which has at least one diffractive effect zone as at least one part of a view region of the spectacle lens such that the spectacle lens comprises diffractive microstructures in the diffractive effect zone, said microstructures generating at least one base effect in each view point of the diffractive effect zone or a myopia corrective effect which deviates therefrom, wherein the diffractive effect zone comprises a combination zone in which the diffractive microstructures generate a combination of the base effect and the myopia corrective effect simultaneously.

Description

[0001] "Myopia stop lenses with continuous power distribution" Description The invention relates to a spectacle lens with a diffractive microstructure for the simultaneous generation of at least two different powers across at least a partial area of ​​the lens to improve long-term wearing comfort. Especially with spectacle lenses for correcting myopia, the often noticeable tendency for myopia progression leads to a decrease in the wearing comfort of once fitted spectacle lenses and thus also the wearer's satisfaction and the tolerability of the spectacles after a short time. In general, myopia is increasing dramatically worldwide, particularly in Asia. The WHO estimates that by 2050, over 50% of all people will be myopic. As the myopia of an individual increases, the risk of associated eye diseases such as retinal detachment, glaucoma, cataracts, and macular degeneration also increases significantly.There is therefore great interest in slowing the progression of myopia. There are several approaches to slowing the progression of myopia using optical aids (vision aids). However, what all these approaches have in common is that they are very complex and expensive, and also relatively inflexible when it comes to adapting to rapidly changing circumstances (e.g., changes in eyeglass prescriptions, demands on the visual system). To date, various optical effects regarding the tolerability and comfort of ophthalmic lenses, particularly spectacle lenses, have been investigated with regard to their influence on myopia and / or hyperopia, as well as their progression or development depending on the optical and physiological mechanisms that are intended to explain or slow down progression or advancement, particularly deterioration.Existing approaches are essentially based on projecting the image in front of the retina, as this is intended to slow the longitudinal growth of the eye. It has been shown that it is sufficient (or even better) if this occurs only in the periphery of the retina. One possible approach is the use of bifocal lenses and / or progressive lenses (PAL). On the one hand, the addition of the lenses projects an area in the peripheral region in front of the retina when looking into the distance, and on the other hand, when looking up close, at least when accommodation is insufficient, the image is not projected behind the retina. This works better for children with accommodative insufficiency and / or convergence excess. However, with such approaches, acceptable results are only achieved in a small group with convergence excess. Bifocal lenses are cosmetically unacceptable, especially for children.Another approach is based on special PAL (or radially symmetric PAL) with a central sharp image and peripheral addition (e.g. DE 102009053467 A1). PAL, as in these two approaches, have areas with large aberrations. If the lens power changes, which is often the case with children, a new, expensive lens must be manufactured at great expense. Furthermore, peripheral vision and also foveal vision when looking through the periphery of the lens are severely impaired by the aberrations. If high demands are placed on the visual system (e.g. in road traffic), this can only be solved with a second pair of single-vision glasses. This further increases the effort and cost of changing the prescription. The acceptance of such solutions is therefore often low. Other approaches are based, for example, on special contact lenses.For example, progressive contact lenses with a higher plus power in the periphery than in the central area have been studied. However, this also impairs foveal vision when the contact lens moves on the eye. Furthermore, here too, a change in power requires a new lens to be made, which is a complex process. Furthermore, handling and reliability are limited in children. This is particularly true for young children, and what makes it even more difficult is that the greatest effect is actually achieved when measures to slow myopia begin in early childhood. Another approach with contact lenses uses so-called Ortho-K contact lenses, which are worn overnight and deform the cornea. This is intended to correct myopia centrally and also create a plus power in the periphery (compared to the central one).Here, too, each contact lens has special requirements and a new lens must be manufactured at great expense, e.g. in the case of a new prescription. Furthermore, the effects of corneal deformation on the metabolism and structure of the cornea are unclear, particularly in young children. The problem for spectacle wearers resulting from the progression of myopia is the steadily decreasing comfort of glasses once fitted. One possible approach to myopia control is the use of spectacle lenses with small additional lenses (so-called lenslets) with additional positive refractive power. These additional lenses are made of knob-like structures. The additional effect leads to a local shift of the focal point in front of the retina and is intended to counteract excessive longitudinal growth of the eye.In the zone with the lenslets (hereinafter "active zone"), the power distribution is discontinuous: In the area of ​​the lenslets, the image is blurred, while in the area between them it is sharp. When looking through the zone, these lenslets are irritating because they locally prevent a sharp image. When the eye moves through this zone while looking, further irritation occurs because the arrangement of the lenslets in front of the pupil changes depending on the direction of view. The object of the present invention is therefore to improve the lasting compatibility of spectacles and thus to achieve long-term wearing comfort in a cost-effective manner. This object is achieved according to the invention by a spectacle lens having the features specified in the independent claims. Preferred embodiments are the subject of the dependent claims.The invention thus provides a spectacle lens having at least one diffractive power zone as at least part of a viewing area of ​​the spectacle lens, such that the spectacle lens comprises diffractive microstructures in the diffractive power zone that produce at least one basic power or a deviating myopic stopping power at each viewing point of the diffractive power zone. The diffractive power zone comprises a combination zone in which the diffractive microstructures simultaneously produce a combination of the basic power and the myopic stopping power. The basic power is understood to be a dioptric power according to a spherical equivalent for compensating for a misrefraction of an eye of a spectacle wearer. The myopic stopping power forms a dioptric power that deviates from the basic power.By implementing the basic power and the myopia stopping power using diffractive microstructures in the combination zone, it is now possible to create local transitions in the intensity ratio (i.e., the proportion of the basic power to the myopia stopping power) without visible steps and apparent inhomogeneities in the transparency of the spectacle lens. For example, areas with a pure basic power (e.g., in the center of a spectacle lens) can be converted quasi-continuously into (e.g., ring-shaped) areas in which the myopia stopping power is additionally or predominantly generated, without these areas having an apparently different transparency. This reduces eye irritation during gaze movements, for example, compared to the use of refractive microlenses for the local creation of additional focus areas.The myopia stopping power is understood to mean the corresponding overall power of the spectacle lens at the respective visual point. This can also be influenced by a refractive effect of the lens body or its surface curvature. For example, the diffractive microstructures of the spectacle lens can be formed on a first lens surface that has a base curve (curvature) which, together with a second, opposite lens surface, produces a refractive effect as a plus lens (converging lens) or minus lens (diffused lens). The overall power of the spectacle lens is then split by the diffractive microstructures into the basic power and the myopia stopping power (with different focal lengths). The diffractive microstructures preferably produce a sharp image, at least for the basic power.For the myopic stopping power, it is not absolutely necessary that a single sharp image (with a different focal length) be created. Multiple focal lengths with different diffraction orders could also be created. Preferably, the myopic stopping power has a shorter focal length than the basic power, particularly at each visual point in the combination zone. The difference in focal length should also be referred to here as the additional power (of the myopic stopping power compared to the basic power). The additional power preferably lies in a range of approximately 1.5 dpt to approximately 5 dpt, in particular in a range of approximately 2 dpt to approximately 4 dpt. To the extent that the basic power leads to a sharp image on the retina, an image in front of the retina is achieved precisely when a shorter focal length is created, which dampens excessive longitudinal growth of the eye and thus efficiently leads to long-term wearing comfort for the spectacle lens.It is not absolutely necessary for the invention that the basic power and the myopia stopping power are the same across the entire spectacle lens or even just across the diffractive power zone. Rather, both the basic power and the myopia stopping power could be different for different viewing directions, as is known, for example, for conventional progressive lenses. However, it is particularly preferred if at least the additional power (i.e. the difference between the focal lengths of the basic power and the myopia stopping power) remains essentially constant in the combination range, i.e. does not differ significantly for different viewing points within the combination zone, in particular by no more than approximately 2 dpt, preferably no more than approximately 1 dpt. In other words, when the basic power changes across the spectacle lens (in particular across the combination zone), the myopia stopping power is preferably also changed.As far as the simultaneous generation of the basic power and the myopic stopping power (in the combination zone) is mentioned here, this is intended to express that the diffractive microstructures in an environment representing the cross-section of an object-point-related light beam through the pupil of a spectacle wearer interact around a corresponding viewing point to generate both powers (basic power and myopic stopping power) simultaneously. This environment can preferably be considered to be a circular disk with a diameter in the range of approximately 1.5 mm to approximately 8 mm, preferably in a range of approximately 3 mm to approximately 6 mm, even more preferably in a range of not more than approximately 5 mm or even not more than approximately 4 mm, or even not more than approximately 3 mm.The consideration of such an environment around the respective viewing point is interesting in that the diffractive effect results from an interference of wavefronts with a finite lateral extent, whereby the geometry (e.g. periodicity, amplitude or step / jump height, glaze angle, etc.) of the diffractive microstructures varies across this environment. This can be particularly the case if the fundamental effect and the myopia stopping effect are generated by spatially separated diffractive substructures within the combination zone, i.e. the fundamental effect is generated by one of the substructures and the myopia stopping effect by another of the substructures. In this case, the two substructures are then so close together (particularly alternating with each other) that the observed environment around each viewing point in the combination zone always contains both substructures.As a result, the basic power and the myopia stopping power are not perceived by the eye as spatially separate from one another. For this characterization of the diffractive microstructures (in particular such substructures) and their optical effect for a respective visual point (in particular within the combination zone), it is particularly possible to consider a circular environment around the visual point, which has a diameter of no more than 3 mm, or even no more than 2 mm, or even no more than 1 mm. Preferably, the diffractive microstructures are formed in a ring shape around a center of the spectacle lens. Particularly preferably, the diffractive microstructures are formed rotationally symmetrically. Preferably, the diffractive microstructures have a sawtooth shape in a cross-section. Preferably, the diffractive microstructures have constant step heights.However, the radial distances of the steps are preferably dependent on the distance from the center and, in particular, decrease substantially inversely proportional to the distance from the center. In a preferred embodiment, the fundamental effect and the myopia stopping effect are each caused by a corresponding diffraction order of the light diffraction by the diffractive microstructures. Particularly preferably, the fundamental effect and / or the myopia stopping effect is generated as the zeroth diffraction order of the diffractive microstructures. In a preferred embodiment, the diffractive microstructures have at least substantially a simple periodicity for each viewing point (of a plurality of viewing points) within the combination zone, wherein the fundamental effect and the myopia stopping effect are caused by different diffraction orders of the (simple) diffraction grating formed thereby.The respective diffraction orders of the fundamental power and the myopia stopping power particularly preferably differ from one another by 1. In a preferred embodiment, the diffractive microstructures comprise, for each viewing point of a plurality of viewing points within the combination zone: - at least one first diffractive substructure, which essentially generates the fundamental power; and - at least one second diffractive substructure, which essentially generates the myopia stopping power. Particularly preferably, the at least one first substructure is formed by a first periodic diffraction grating with a first grating period and a first grating amplitude, while the at least one second substructure is formed by a second periodic diffraction grating with a second grating period and a second grating amplitude.The term "grating amplitude" here does not refer to the influence of a conventional amplitude grating on the local attenuation of a light wave. Rather, it generally refers to the local influence on the light wave. This can indeed be an attenuation of the light wave by a conventional amplitude grating. However, within the scope of the present invention, it is preferred to use phase gratings through a refractive index transition. Particularly for the preferred case of a phase grating (due to refractive index transitions), the "grating amplitude" referred to here describes the spatially variable (in particular periodic) influence on the optical path length, i.e., for example, the local layer thickness of a layer forming the diffractive microstructures with a refractive index that differs from the refractive index of the base body of the spectacle lens.For example, in the case of sawtooth-shaped microstructures, the grating amplitude can be described by the jump height of the sawtooth-shaped cross-section of the microstructures. In a particularly preferred embodiment, the first grating amplitude and the second grating amplitude differ from one another, while preferably the first and second grating periods essentially coincide. In this case, "essentially" means in particular that deviations from exact agreement should be possible, which in particular realize a global radial variation of grating periods across the entire spectacle lens. In this embodiment, in the case of (essentially) identical grating periods, the two substructures correspond to one another to a certain extent in their diffraction factors. However, they differ from one another in their form factors. This will be explained in more detail later.The different grating amplitudes (form factors) allow for the targeted selection of different diffraction orders of the respective substructure, which provide the fundamental power and the myopia stopping power. In a further preferred embodiment, the first grating period and the second grating period differ from one another, while preferably the first and second grating amplitudes essentially coincide. This embodiment results in particularly great flexibility, since both the absolute value of the fundamental power and the myopia stopping power as well as their relative position, i.e., the additional power, can be adjusted relatively freely (in particular, continuously) via the continuously selectable grating periods. In particular, there is no restriction to the specific selection of diffraction orders (i.e., in steps).In principle, it is also possible for both the grating amplitudes and the grating periods of the two substructures to differ from each other, which can provide a further greater degree of freedom for selecting / adjusting the fundamental and myopic stopping power. The diffractive microstructures preferably comprise a plurality of first substructures and a plurality of second substructures, each arranged alternately with each other. In other words, at least within the combination zone, there is usually a second substructure between two first substructures, and vice versa.Particularly when using a plurality of alternately arranged first and second substructures, it is particularly preferred if, along a contiguous path (in particular extending radially on the spectacle lens) within the combination zone, a number of the first grating periods of the first substructures and a number of the second grating periods of the second substructures change successively in opposite directions. In other words, along a contiguous path that alternately traverses first and second substructures, one number of grating periods increases, while along the same path the other number of grating periods decreases. Thus, along the path, the respective area of ​​one type of substructure also increases (quasi)continuously, while the respective area of ​​the other type of substructure decreases (quasi)continuously.This achieves a (quasi-)continuous change in the proportion of the fundamental power relative to the proportion of the myopia stopping power, whereby the eye does not perceive any (step-like) inhomogeneity of the lens. Preferably, the number of grating periods in each substructure is in the range of about 2 to about 200, preferably in a range of at least about 5, even more preferably at least about 10, and / or in a range of no more than about 100. The invention is further described below using preferred embodiments with reference to the accompanying drawings. Therein: Figs. 1A to 1D show schematic cross-sections through exemplary spectacle lenses to illustrate the diffractive gratings formed by the diffractive microstructures; Fig. 2 shows a schematic illustration for determining the phase difference for two adjacent rays at an arbitrary, not necessarily periodic, surface; Fig.3 a prism with a back surface grating with blaze angle to illustrate locally periodic microstructures; Fig. 4 prism with a complex structured grating: the section within a period is divided into different subsections, which can represent substructures; Fig. 5 distributions of diffraction factor, shape factor, and total intensity as a function of the angle of reflection φ' for the blaze angle β=3.8°; Fig. 6 intensity distribution in orders 0 and -1 as well as in the sum of the remaining orders as a function of the blaze angle; Fig. 7A to 7D schematic cross-sections of preferred diffractive microstructures based on several substructures; Fig. 8 distributions of diffraction factor, shape factor, and total intensity as a function of the angle of reflection φ' for a further example of a diffractive microstructure; Fig. 9 the intensity distributions for different orders as a function of the number of grating periods per substructure; Fig.10A and 10B show examples of particularly simple microstructures. The present invention thus provides spectacle lenses in which, in an active zone (diffractive action zone or combination zone), at least part of the light enables a sharp image on the wearer's retina, while another part of the light is focused in such a way that a stimulus is provided against the myopia-causing increase in eye length. In contrast to conventional spectacle lenses, a spectacle lens according to the invention also offers a substantially homogeneous image in the active zone. In particular, a continuous visual impression is created during pupil movement. In general, the active zone, or the diffractive action zone and / or the combination zone, are not limited to specific areas on the spectacle lens. Thus, the diffractive effect can essentially be used freely anywhere on the spectacle lens.However, the combination zone particularly preferably omits at least a central viewing area of ​​the spectacle lens (e.g. with a diameter of approximately 10 mm or even approximately 15 mm). More preferably, the combination zone fills an annular area between a radius of approximately 20 mm and approximately 35 mm, or even between a radius of approximately 20 mm and approximately 40 mm, or even between a radius of approximately 15 mm and approximately 50 mm. With a spectacle lens according to the invention, it is achieved in particular that part of the light is focused on the retina with a first effect (basic effect, SG) and another part of the light is focused with a second effect (myopia stopping effect, S. M ), which is more positive than the basic effect by a third effect (additional effect ΔS), is focused in front of the retina. A fourth effect (effect of the basic lens S K) contribute to both the fundamental power and the myopia stopping power. This effect can also be zero or change across the entire lens area. Special diffractive microstructures additionally contribute to the myopia stopping power and / or the fundamental power. At least the splitting into the fundamental power and the myopia stopping power is caused by the diffractive microstructures. Fig. 1A to 1D, which will be described in more detail later, schematically illustrate examples of a possible structure of the spectacle lens consisting of a base lens and the diffractive microstructure. Although both can preferably be formed integrally from the same material, it is nevertheless possible, at least in terms of a model, to distinguish the macroscopic curvature of the base lens with its refractive power from the microstructures with their diffractive effect. As will be explained in more detail below, the preferred axial extent of the diffractive microstructures depends on the diffraction orders used.It is determined in particular as the product of the diffraction order and the design wavelength divided by the difference in the refractive indices of the two media. In preferred embodiments, the first diffraction order is used. The lateral dimensions of corresponding diffraction gratings are typically in the range of approximately 1 mm to approximately 0.01 mm. However, more specific details for specific embodiments will be explained later. The lateral extent of the individual grating elements (periods) of the diffraction grating results from the design of the structure. For simple gratings, the principle applies that the lateral extent is linearly reciprocal to the prismatic power of the glass at that point. For a given sphero-cylindrical power, this power must increase from the center to the edge of the glass according to the Prentice formula prism = power * radius. The extent is therefore in particular reciprocal to the radius.The Prentice formula also shows that the prismatic power increases with the desired sphero-cylindrical power. This results in a wide range of lateral dimensions for the individual grating elements. This will be explained in more detail later. The variation in magnitude can be clearly explained by the fact that, for example, in a diffractive lens with a power of around 10 dpt, the magnitude of the grating constant in the region of the center of the lens is in the region of 1 mm, and in the periphery, via the 1 / r law, it is typically 1 / 30 of this, i.e. 0.03 mm or slightly less. The diffractive grating (i.e. the diffractive microstructures) can act against air, as is illustrated in Fig. 1A to 1D. Nevertheless, thin layers that do not significantly change the structure can be applied if necessary, e.g. as a hard coating, anti-reflective coating or topcoat.In a preferred embodiment, the structure is covered by a cover layer that is thicker than the structure height and preferably offers a flat surface. The refractive index of this layer must then be taken into account in the effect of the structure. In a preferred embodiment, the diffractive structure is applied rotationally symmetrically around the center or the principal viewing point or the far point of the spectacle lens. This avoids unwanted prismatic effects and the design of the lens can be defined particularly easily around the corresponding point. In a further preferred embodiment, the periodicity or the course of the grating is rotationally symmetrical around the center, but not necessarily the structure height. This allows, for example, structures in which the intensity distribution depends on the polar angle.The fundamental effect is represented by the effect of the ground glass and the effect Sdiff,G of the mG-th diffraction order of the diffractive structure of the diffraction grating. The myopic stopping effect results from the effect of the ground glass and the (at least one) effect Sdiff,M of the (at least one) mM-th order. The difference between the effect of the mG-th and the mM-th diffraction order(s) is thus the additional effect ΔS. The portion of the incident radiation that goes into the fundamental effect (the mG-th diffraction order) and the portion of the incident radiation that goes into the (at least one) myopic stopping effect (m. M-th diffraction order) is determined by the structure (e.g. height) of the diffractive grating. This can be set so that a desired intensity distribution is realized. This will be explained in more detail below. Part of the incident radiation can also be diffracted into further orders. This can be undesirable and can be minimized as much as possible. This can be achieved in particular by appropriately choosing the structure height (or amplitude or jump height) of the diffractive microstructure, as will be explained in more detail below. As an alternative to just a single m M-th order of diffraction, the myopic stopping power can also be formed from several diffraction orders. This is possible because its primary purpose is to provide an incentive against further longitudinal growth of the eye and not to produce a sharp image. In a preferred case, the orders of the basic power mG and myopic stopping power m M directly next to each other (m M = m G ± 1). In this case, the grating can take on a sawtooth shape, and the intensity distribution can be controlled by the height of the respective spikes. In the simplest case, mG = 0 and therefore m M= ±1. The basic power is therefore not influenced by the diffractive structure and corresponds to the power of the base lens. The diffractive structure thus provides the additional power. However, other mG values ​​can also be selected. This allows the power of the base lens to be reduced, and thus the curvature of the surfaces and ultimately the thickness of the lens, while maintaining the same basic power. Furthermore, by skillfully selecting the power of the base lens and the power of the grating in the mG-th order, the chromatic aberration for the basic power can be reduced. As a first approximation, the dioptric power is ^ ^^^^ of the diffractive grating for a given grating parameter ^ linear for the wavelength ^ dependent on the diffraction order m: ^ ^^^^ ^^^ = ^^ ^ (G1) The lattice parameter A describes the periodicity of the lattice as a function of the distance from the center. Details on the structure of the lattice and the definition of the lattice parameter will be discussed in more detail below. 16

[0002] While it is advantageous to minimize (or at least not increase) the chromatic aberration for the image created by the basic power, a (greater) chromatic aberration can be accepted when creating the image created by the myopic stop power, since a sharp image on the retina is not achieved anyway. The necessary division of the total effect between the refractive component (effect of the basic lens) and the diffractive component to fully compensate for the chromatic aberration depends on the refractive indices of the materials of the lens body riK and any cover layer ns, as well as the Abbe number v Kthe material of the lens body. Details on this, including the definition of the chromatic aberration parameter o as a function of the material parameters, will be discussed in more detail below.

[0003] The chromatic aberration does not necessarily have to be completely compensated. It is sufficient if the chromatic aberration is partially compensated or partially overcompensated, i.e., a smaller chromatic aberration (in the normal or abnormal direction) remains than would be the case with a purely refractive lens.

[0004] An improvement can already be achieved if where <J0eine von der Abbezahl und dem Brechungsindex abhängige Konstante ist, wie später noch ausgeführt wird. Bei den üblichen Materialien liegt <J0im Bereich von 0,09.

[0005] Some examples are summarized in Table 1.

[0006] Sdiff.G [dpt] Sditf.M [dpt]

[0007] S G[dpt] SM [dpt] zlS [dpt] SK [dpt] Remark

[0008] (m G ) (m M )

[0009] 0.0 + 3.0 Simplest case

[0010] + 2.0 + 5.0 + 3.0 + 2.0 (0) (1 ) plus glass

[0011] - 2.0 + 1 ,5 + 3.5 - 2.0 0.0 + 3.5 Simplest case (0) (1) Minus glass Table 1: Examples of effects and diffraction orders with m M = m G ± 1 As also described below, small portions of the incident light can also be diffracted into neighboring diffraction orders (mainly into the directly neighboring diffraction orders m M - 1 and m M + 2 or m M - 2 and m M+ 1). However, as long as the structure is of sufficient quality and the diffraction into unwanted orders is not too high, this is acceptable and does not hinder the use. Preferably, the proportion of diffraction into unwanted orders in regions where full correction is to be achieved (particularly in central visual areas and / or in distance vision areas and / or in near vision areas, i.e. in the mainly used visual areas of the spectacle lens) is not greater than approximately 5%, even more preferably not greater than approximately 3%, and most preferably not greater than approximately 1%. In other regions, a proportion of 20% or more in unwanted orders could still be tolerable. There are cases in which the proportion of foreign orders cannot be reduced any further. For example, ifIf two neighboring orders achieve the same intensity, then there is a theoretical minimum of just over 20% of the energy that unintentionally ends up in other orders. However, there is not a sharp theoretical limit for every situation. Using neighboring diffraction orders of a sawtooth structure avoids unnecessary complexity and allows sufficient flexibility for most applications. Thus, all desired additional effects can be realized by choosing the lattice parameter A. However, there is a certain dependence between the fundamental effect and the additional effect, since according to equation (G1), ^ ±^ ^ =. ^^ ^ ^ ∙ ^ ^ ^^^^,^ ^^^^,^= ^ ^ ∙ ^ ^^^^,^ (G3) In many cases, however, the flexibility is sufficient, since, for example, chromatic aberration correction is more relevant for high powers than for low powers. For some applications, it may be useful to increase flexibility in adjusting the powers by not restricting the power to neighboring diffraction orders. This allows for power distributions with arbitrary integer ratios. ^ ^^^^,^ = ^^ ^ ^ ∙ ^ ^^^^,^ (G4) This allows, for example, chromatic aberration correction for lower primary powers or higher additional powers, as well as better matching to the chromatic aberration of the primary lens. Furthermore, the additional power can be finely tuned if the primary power is to be created solely or predominantly by the grating. Some examples are summarized in Table 2. Sdiff,G [dpt] Sdiff,M [dpt] S G [dpt] S M [dpt] ∆ S [dpt] S K[dpt] Remark Compared to the situation in Table 1, the chromatic aberration compensation is almost complete here and the additional effect is significantly higher. Secondary maxima can also occur in the intensity distribution. For the primary effect, the aim is to use only one maximum (or closely adjacent secondary maxima) to ensure a sharp image. For the myopic stopping effect, however, several maxima (especially secondary maxima) with greater spacing can be used, since a sharp image is less important here. Overall, the influencing factors on the design of the diffractive microstructures are better understood through the following basic explanations. For example, US 2013 / 0229619 A1 (and US 2013 / 0235337 A1) describes the optical properties of a (particularly at least locally flat) surface that has a periodic sagittal height according to the equation ∆φ + ∆φ = ∆φ, 0 ≤ ≤ ∆φ (1) ^ ^!^If a parallel light beam (plane wavefront) falls on such a surface at any angle and covers the entire width 0 ≤ ! ≤ '#, then the outgoing light has an angular distribution of intensity ( = ( ) × ( , which is the product of a diffraction factor ( and a form factor ( )can be understood as. The diffraction factor (apart from the angle of incidence) depends only on the period # and the number of periods '. The form factor, on the other hand, is independent of ', but depends on the form of the function ^ ^!^ within a period. The background to the application of diffractive structures in US 2013 / 0229619 A1 is the possibility of color fringing correction. In contrast, it is now proposed to use diffractive gratings to improve the long-term wearing comfort of spectacle lenses by suppressing the progression of myopia. The desired optical properties consist in the lens producing, in addition to a basic power, a second image which is created in front of the retina, typically with an additional power of in particular around +3 dpt. Overall, this additional power is preferably in a range from around +1.5 dpt to around +5 dpt. To illustrate the principle, the prism orthe flat surface can be viewed with an equidistant grating. This already describes it very well locally (i.e. for a specific viewing point and its local surroundings). The results can then be transferred to lenses in a similar way to the procedure in US 2013 / 0229619 A1. Thus, the following explains how the intensity distribution changes when more complex structures are permitted within a grating period, such as different grating constants and different blaze angles in substructures. For better clarity, the initial situation from US 2013 / 0229619 A1 regarding equidistant gratings is summarized here again with slightly different nomenclature. The situation of a finite equidistant grating with ' periods is assumed, where the grating profile can initially be arbitrary. The normal of the surface on which the grating is applied points in the z-direction, and the grating is defined by the profile^ ^!^, 0 ≤ ! ≤ !.^ = '# is defined from equation (1). If light (coherent across the entire width of the grating) is incident on the grating at an angle of incidence + relative to the surface normal, then it is useful to first determine the resulting phase shift as a function of !. As can be seen from Fig. 2, two neighboring rays enter into a phase relationship even with any type of grating, not necessarily a periodic one. If the intersection points are defined by ! ^ ! , / ^ = - ^ ^!^^ ., , / = - ^ ^! / ^ . (2) are given, then one can define the projection sections ^ ^ , ^ / calculate by ^^, ^ + ^ ^ 0′^ − , / ^0′ = 2 (3) λ1 = (P2 −P 1 ) N ' (4) The phase difference of beam 2 compared to beam 1 is now Φ21 =n 'λ1 + n λ 2 ' ' ' ' ) with the abbreviations 34^+, +′^ = ^^′ 56^ + ′ − ^ 56^ +^ ; 38^+, +′^ = ^^′ 9:5 + ′ − ^ 9:5 +^ (7) If the refracting surface is actually flat, ie ^ ^!^ ≡ 0 holds, then the second term disappears, and the law of refraction would follow from the first by requiring a vanishing phase difference for all !. The phase of any ray, defined as the phase difference compared to the ray at ! = 0, is, assuming ^ ^0^ = 0: <^+, +′, !^ = !^^′ 56^ + ′ − ^ 56^ +^ + ^ ^!^^^′ 9:5 + ′ − ^ 9:5 +^ (8) Conveniently, the phase can also be introduced as the function <^34, 38, !^ = !34+ ^ ^!^38(9) The amplitude in the failure direction +′ is =^34, 38^ ^ ^ > AB^ ?!3^6@<^34, 38, !^^#! (10) with @ ^ 2C / ^ (measurement factors were neglected here, which are intended to take into account that different oblique positions on the grating are hit by different “numbers” of rays per unit area). If @ ^ 2C / ^ and the periodicity condition from Eq.(1) holds, then Eq.(10) can be rewritten as where after the substitution the periodicity was exploited. The front factor is a form factor = ) ^#, 34, 38^ , and the posterior factor = ^', #, 34^ takes into account the periodicity of the diffractive grating, and is therefore a diffraction factor. The intensity distribution is thus given by 2 I ( ps , pc , N , d ) = U ( ps , pc , N , d ) For practical reasons, new notations for the argument are now introduced: @ # ^ / E ^ #: ^ 2CG (13) The diffraction factor can then be rewritten as Exp Nikdp Exp - Nikdp - Exp Nikdp UD ( ps , N , d ) = ( s / 2 ) ( s / 2 ) ( s / 2 ) as well as J KL / 4^I- MN . 4^I^ ^ / ( ^34' #^ ^ H KL O MP ( ^34' G^ ^ - QERSN ^ ^ ^ . (15) The function 56^^ '!^ / 56^ ! is known to have sharp maxima wherever ! ^ C^, ^ ∈ U. This means that maxima occur where This is the well-known diffractive extension of the law of refraction. The form factor is given by and cannot be simplified further without further assumptions. However, for the special case of a sawtooth grating, the following applies: ^ ^!^ ^ 1! VW^ X , 0 & ! & # (18) where X is the so-called blazing angle. Its sign is initially arbitrary, and is chosen in the following such that XY 0 describes the case where a back surface grating on a prism with base down (see Fig. 3) magnifies the prism. Thus, where X was included as an additional argument. The factor Z : ^ ^3 4 138 VW^ X^ (20) has a very vivid meaning, namely

[0012] Damian and (23) Here, sinc! ^ 56^ ! / ! is the diffraction amplitude of the single slit. It has its maximum where the argument ! ^ is 0, and at all other zeros of the numerator, ! ^ C^ ) , ^ ) ∈ U\`0a, there is a zero. This means that for 3 4b ^ 0 ⇔ ^′ 56^^ +′ 1 X^ 1 ^ 56^^ + 1 X^ ^ 0 (24) the maximum is to be expected, i.e. in the direction in which classically, ie without the wave nature of light, the refraction would already take place. The zeros are for ^ ) d 0, in alternative notations, at kdp s β / cos β = pi m F For practical reasons (in favor of a normalized representation of the diffraction factor, form factor and total intensity), normalized functions are introduced for the diffraction factor and the form factor, which have the value 1 at the central maximum: (26) (27) (28) Fig. 3 illustrates a complex or combined lattice and represents a variant with different substructures. For its mathematical description, starting from the sagittal representation in Eq. (18), the period of length # can be divided according to # ^ # ^ " # / ⇒ # / = # / ^#, # ^ ^ (29) where preferably in section # ^ in f ^ Grid lines divided with a blaze angle X ^ , section # / on the other hand i f / Grid lines divided with a blaze angle X / . The arrow height in section # ^ is then described by ì1! VW^ X^ , 0 & ! & k^1^! 1 k^^ VW^ X^ k^ & ! & 2k^and in section ì1! VW^ X / , 0 & ! & k / 1^! 1 k ^ VW^ X k & ! & 2k The total intensity is then still described by Eq.(12), but the form factor can be described by the sum of both sections instead of the amplitude from Eq.(22) = ) ^34, 38, # ^ , # / , X ^ , X / , f ^ , f / ^ ^ ∑ / pr^ = ^p^ ) ^34, 38, `# q a, X p , f p ^ (33) For section # p you get With the abbreviations Z p ^ 34138VW^ X p , ℎ = 1.2 (35) is obtained after simplification (where the index 'ℎ' is omitted from the dummy arguments):

[0013] as well as If we set again as in Eq.(13) as abbreviation @k ^ / E ^ k: ^ 2CG t (38) then Overall, the intensity of the form factor The normalized form factor intensity is then according to Eq.(27) where the intensities of the sub-grids are abbreviated ( ^p^ ) ^ ^ u / p , ℎ = 1,2 (45) and for the interference term the ng ( ^^ / ^ ) ^ ^ 2u ^ u / 9:5^ v / 1 v ^ ^ (46) The normalized diffraction factor intensity is given by Eq.(26), so that the total normalized intensity is given as The methodology presented here can be used to design the structure of spectacle lenses with a myopia stopping power. The specific procedure will be explained using three examples of preferred embodiments. Even though these examples are described separately, the specific measures for designing the diffractive microstructures can also be combined. The first example presents how specific (particularly neighboring) diffraction orders of a simple grating can be used for the fundamental power and the myopia stopping power. To investigate the intensity distribution across different orders, one would strictly speaking have to evaluate the energy content of each diffraction order by taking an integral. However, if the peaks of the diffraction factor are sharp enough, it is sufficient to evaluate the form factor at the position of the respective angle of reflection corresponding to a specific diffraction order.For this purpose, a simple diffraction grating (i.e., without splitting) with a blaze angle of X ^ 3.8° is considered. If the intensity (. ^ ^34, 38, #, 0, X, X, 1,1, '^ for X ^ 3.8° (so VW^ X = 0.0664), we obtain for the angle of reflection v′ ^ = 15.09° in order ^ = 0 an intensity of ( ^ = 0.1564. The corresponding intensity for the angle of reflection v′ ^^ = 12.15° in the order ^ ^ 11 is ( ^ ^ 0.6791. The resulting spectrum is shown in Fig.5. Fig. 5 shows the distributions of diffraction factor ( ^ (blue), form factor ( )^ (red), and total intensity ( ^(black) as a function of the angle of reflection φ' for the blaze angle X ^ 3.8°. In this case, the order ^ ^ 0 and the order ^ = −1 are dominant orders, but other orders are also occupied. By appropriately varying the blaze angle X, the intensity can be distributed between different diffraction orders. The dependence of the intensity in the two orders ^ = 0 and ^ = −1 on the blaze angle is shown in Fig. 6. Fig.6 shows a curve of the intensity in the orders ^ = 0 (blue) and ^ = −1 (orange) as well as in the sum of the remaining orders (green) as a function of the blaze angle X. The blaze angle of 3.8° shown corresponds to the situation in Fig. 5. For X ≈ 2.85° (i.e. VW^ X ≈ 0.0497) the same proportion of ( ^= 0.3956 and a remainder of just over 20% for the remaining orders. This variation in the blaze angle corresponds clearly to the variation in the jump height between the integer multiple of the design wavelength divided by the difference in the refractive indices of the media and the next higher integer multiple of the design wavelength divided by the difference in the refractive indices of the media. This allows the previously described embodiments of utilizing neighboring diffraction orders for the fundamental power and the myopia stopping power to be very well implemented and optimized. A second example explains in more detail how the diffractive microstructures can be constructed using substructures with different powers. To obtain an additional degree of freedom compared to simple gratings, the two desired powers (fundamental power and myopia stopping power) can be provided by different subgratings (substructures).In the simplest case, the two effects correspond to the m1-th and m2-th diffraction orders of a grating with the lattice constant (k). Further flexibility is thus achieved by using two substructures instead of a simply periodic structure with a lattice parameter A, namely a first substructure with the respective lattice parameter AG and a second substructure with the lattice parameter AM. These substructures alternate in ring-shaped zones, preferably starting from the center and preferably beginning with the first structure outwards. ZG(j) points (number of first lattice periods) of the first substructure are followed by ZM(j) points (number of second lattice periods) of the second substructure, followed by ZG(j+1) points of the first substructure, and so on. The parameter j is a running variable for numbering the individual zones (or substructures of the same type of substructure, namely first or second).The grating parameters AG or AM and the diffraction order mG or mM are chosen to produce the desired effects Sdiff,G and Sdiff,M. Where "G" stands for the fundamental effect and "M" for the myopia stopping effect. The intensity distribution between the two effects can be controlled using the number of points ZG(j) or ZM(j) (i.e. the respective number of grating periods). This is described in more detail below. The number of points ZG(j) or ZM(j) can vary with j across the lens surface. By dividing the structure into zones or substructures, interference can occur between neighboring zones of different substructure types and / or interference between consecutive zones of the same substructure type. These effects must be taken into account when designing the structure. Interference between neighboring zones of different substructures can, for example, lead to intensities in undesirable (secondary) orders.This effect can be reduced by higher Z, since wider zones reduce the interference between neighboring zones. Furthermore, this effect can be reduced by appropriately matching the AG or AM and the ZG(j) or ZM(j). Fig. 7A to 7D show different arrangements of diffractive microstructures. Fig. 7A shows a periodic grating with only one (locally constant) grating period. Figures 7B to 7D schematically illustrate diffractive microstructures, each with two substructures. The two substructures can be distinguished in the schematic representation by different hatching and otherwise differ technically, in particular by a different grating constant or grating period. In Figures 7B to 7D, a first substructure (vertically striped) is uninterrupted by a second substructure (horizontally striped). In the sections of Fig. 7B to Fig.7D shows two separate zones for the first substructure, separated from each other by a zone of the second substructure. Interference between consecutive zones of the same substructure type is unproblematic for a substructure if the number of spikes is chosen such that the (j+1)th zone of this substructure type, in relation to the jth zone after the interruption by the other substructure (horizontally striped spikes in Figs. 7B, 7C, and 7D), runs in the same way (vertically striped spikes in Figs. 7A and 7D) as if it were not interrupted by the other substructure (Fig. 7A). In this case, constructive interference occurs between the two consecutive zones of one substructure type. This can be achieved by ensuring that the sum of the widths of the individual spikes of the interrupting other substructure corresponds to the sum of the widths of the individual spikes of the displaced substructure (Fig. 7C).However, this is associated with a corresponding restriction of the effects of the two substructures. This restriction can be circumvented if the phase of the interrupted substructure in the j+1 zone is chosen such that it corresponds to the phase position in the uninterrupted case (Fig. 7A). If this condition is not met (Fig. 7C), destructive or not entirely constructive interference can occur between the two consecutive zones of one substructure (i.e., substructure type) in a direction where constructive interference would be necessary, and at least partially constructive interference can occur in directions where (as entirely as possible) destructive interference is desired. This can reduce the intensity in the desired effect and diffract the intensity in undesired effects or directions.As in the case of interference between adjacent zones of different substructures, this effect can be reduced by choosing higher Z, since wider zones reduce the interference between different zones. Irrespective of this, higher Z values ​​allow for finer control of the intensity distribution at approximately the same ratio. Conversely, excessively high Z values ​​can lead to individually perceptible areas. This can be desirable if, for example, only the basic effect is to be provided in a central area. However, if both the basic effect and the myopic stopping effect are to be present within a single area, this can be undesirable. The decisive factor here is the area on the lens through which light penetrates the pupil when the eye is deflected accordingly.To avoid this, at least one zone of each type of substructure can be located within an area surrounding a viewing point, which corresponds to a so-called effective pupil. The effective pupil can be calculated from the power of the glass and the size of the physical pupil and is typically between two and eight millimeters. In the simplest case, the first diffraction order is used for both substructures. This simplifies analytical analysis and ensures uniform, as few high structures as possible. However, higher diffraction orders can also be used. The resulting larger structures can, under certain circumstances, be more easily manufactured with the necessary precision. The diffraction order used can also vary between the two substructures and even between individual zones of the same substructure.This creates additional degrees of freedom in the design of the structures, which can be used to optimize the diffraction behavior of the overall structure. The significance of secondary maxima in the fundamental or myopia stopping power, as well as the design to reduce chromatic errors and their significance in the fundamental or myopia stopping power, applies analogously to what has been described for an individual structure. According to the formalism described below, the two desired effects are achieved by combining two sub-gratings (substructures), each with the same grating constant (k). ^ = k / = k ) but with different jump heights (and thus blaze angles). This offers greater flexibility than the example with only a single periodic grating. The latter only allows the use of two adjacent diffraction orders, whereas any diffraction orders can be combined by varying the blaze angle. This can be illustrated using a superlattice consisting of two sub-lattices with the given properties. As a basis, one can consider a grating that operates in the first diffraction order and is used as the first sub-lattice (first substructure). For the second sub-lattice (second substructure), the same grating period can be used, but with a jump height that corresponds to three times the diffraction order. f ^ = f / = 1 , one obtains for ( ^a relatively broad distribution of four peaks around the central diffraction order of each grating (see Fig. 8). This behavior can be phenomenologically explained by the strong interference of the two substructures. Even a moderate increase in the parameter f ^ and f / This broadening can be narrowed, as simulation calculations tf ^ = f / = 2 (Fig. 9A), f ^ = f / = 5 (Fig. 9B), f ^ = f / = 10 (Fig. 9C) and f ^ = f / = phase shift of the elements of the sub-gratings to each other. A narrow distribution is particularly important for the fundamental power, and at least desirable for the myopia stopping power. This can be achieved, as shown above, by moderately increasing the parameters f ^ and f / Furthermore, a completely different effect can be exploited: In the approximation used in the model presented here, an infinite coherence length is assumed. In reality, however, one is dealing with light of limited coherence length (“in the range of the medium wavelength (order of magnitude 10−6 m)”). Thus, interference only occurs between somewhat neighboring grating elements. This effect leads to higher parameters f ^ and f / to suppress parasitic interference between the elements of different sub-gratings compared to the interference within the respective sub-gratings. The area of ​​the lens occupied by a light beam passing through the pupil of the eye and contributing to the image on the retina can be chosen to be large enough compared to the grating constant to achieve correspondingly large M (synonym for f ^ and / or f / ) without causing irregularities in the visual impression. Preferred values ​​for M are preferably in the range from 5 to 200, particularly preferably from 10 to 100. Furthermore, M can also be made variable over this range. Since the grating constant decreases towards the periphery, the M can increase towards the periphery with the same vignetting through the entrance pupil of the eye. A further suppression of parasitic interference can be achieved by using higher diffraction orders. This is because the number of grating elements participating in the diffraction is further reduced for the given coherence length. As already mentioned, a third example is a grating consisting of two sub-gratings with different grating constants and adapted blaze angles, as has already been described schematically with reference to Fig. 7.The structures of the respective zones do not (necessarily) differ in the diffraction order used, but rather in terms of the lattice constants. This allows for an even broader range of effects, since the effect of the two substructures no longer requires different diffraction orders of the same lattice constant, but the lattice constant can be freely chosen for each zone (substructure) according to the desired effect. In the formalism used here, the two desired effects are therefore realized by combining two sub-lattices with the same jump heights but different lattice constants (and thus blaze angles). This is again investigated using a superlattice consisting of two sub-lattices with the given properties. As a basis, a lattice can be considered that operates in the first diffraction order and is used as the first substructure.The second sub-grating is considered to be a grating with four times the lattice constant. Since the intensity of the contribution of each sub-grating depends on the area it occupies, for each lattice element from the lattice with the higher lattice constant, a corresponding number of lattice elements from the lattice with the lower lattice constant could be selected to achieve the same intensity. However, this is preferably deliberately deviated from if a different (especially a locally different) intensity distribution is desired. Here, too, one obtains f. ^ = 1 and f / = 4 for ( ^ a relatively broad distribution of five peaks each around the z ntral diffraction order of the individual gratings. Again, this broadening can be narrowed by a moderate increase in the Ms, as simulation calculations with f ^ = 2, 5 and 10 (and f / = 4f ^). For the phenomenological understanding, the application for the construction of a superlattice with two narrow intensity distributions and the exploitation of the limited coherence length of natural radiation, the same applies as already explained for the second example. In the case of a spectacle lens, in contrast to a prism, the grating "constant" is preferably not constant across the entire lens, but slowly variable. Especially for a lens, the state of the art reveals a dependence corresponding to #(^)~1 / ^, where ^ is the distance from the lens center (see e.g. US 2013 / 0235337 A1). Such a decrease in the grating period towards the edge is also schematically illustrated in Fig. 1A to 1D.Since the jump heights of the grating points can be chosen to be constant even for a spectacle lens to a good approximation, and since the blaze angle is given by VW^ X = ℎ / #(^) , the steepness of the grating points increases for increasing radius according to VW^ X ~^. With the method presented here, in particular the effect of a superlattice consisting of two sub-lattices in the approximation of Fraunhofer diffraction and an infinitely long coherence length can be simulated. Three different grating concepts were investigated as examples. This shows the occurrence of interference between the sub-lattices that is undesirable for the application. This leads to a broadening of the actually desired sharp diffraction orders. In reality, however, this can be sufficiently narrowed by increasing the grating factors M.Additionally, these parasitic interferences can be suppressed by transitioning to higher Ms and / or higher diffraction orders, since in natural radiation the coherence length and thus the ability to interfere across more distant grating elements (laterally and axially) is limited. Even though the investigation was conducted for gratings with prismatic powers and constant grating constants, the results and design principles can be transferred to other gratings according to the invention with dioptric power and defined variation of the grating constants. The invention is not limited to the structures analytically described above. Further possibilities include holographic structures, in which the structure is determined or manufactured as a holographic structure based on the desired light distribution for a given irradiation level.The intensity distribution between the fundamental power and the myopia stopping power can be constant across the entire lens or variable depending on the respective location on the lens. This allows, for example, zones with only the fundamental power, zones with both powers, and zones with only the myopia stopping power to be created. The zones can be, for example, annular, full-sector-shaped, or annular-sector-shaped. An advantage of this invention is that it not only distinguishes between a region of the fundamental power and a region with the myopia stopping power, but also allows a continuous transition to be formed. A simple grating with a single diffraction order can only provide one power.The simplest structure according to the invention would be a simple grating (in particular with a grating constant decreasing towards the outside and) with a radius-dependent jump height that controls the power distribution between the fundamental power (0th diffraction order) and the myopia stop power (1st diffraction order). A simple example of a myopia stop lens could look like this: A diffractive grating applied to a lens and with a grating constant d(r) = A / r, where r is the distance from the center of the lens, has a refractive power of -mλ / A at wavelength λ and in the diffraction order m. The jump height is h = mλ / (n-1) if the intensity is to end up in the m-th diffraction order. If one wants to create a myopia stop lens that has no additional diffractive power in the center of the lens but in the order m = 1 on the outside, then the jump height can have a transition between h = 0 and h = λ / (n-1). The myopia stopping effect at the wavelength λ=550nm should be approximately ΔS=2.3 dpt, then a constant A = 2.4 x 10-7 m2 is required. A grating that has a constant myopia stopping power ΔS is shown in Fig. 10A. If a transition is to be installed that has zero power in the center but ΔS in the periphery, then the center can be attenuated as shown in Fig. 10B. The following are exemplary details of the shapes and dimensions of preferred diffractive microstructures for use in the present invention. In particular, diffractive microstructures with simple periodicity will be discussed first. With these diffractive microstructures, either one diffraction order (complete intensity in one diffraction order) or, for example, two neighboring diffraction orders can be used. As in the exemplary embodiments from Fig. 1A to Fig.As shown in Figure 2D, the diffractive microstructures are preferably rotationally symmetrical around a glass center, so that a definition of the cross-section along a meridian is sufficient. Preferably, the meridians follow at defined intervals. ^ , ^ / , ^ ^ , … one edge each, where the ^ ^ from the glass center, preferably in the vertical plane (i.e., the tangential plane at the glass center) as projections perpendicular to the vertical plane. Preferably, all edges have, at least locally, essentially the same jump height ℎ . This is preferably also measured perpendicular to the vertical plane. However, it can also be measured perpendicular to the glass surface. The difference is usually only slight and not relevant in this approximation. Preferably, the same curvature @ is present everywhere on the edge-free sections of the diffractive microstructures (i.e., between the edges). ^Thus, the edges in the cross-section shown preferably form a lattice with a radially variable lattice constant #. In particular, # ^ = ^ ^^^ − ^ ^ or # ^ = ^ ^ − ^ ^^^ . The lattice constant # can be particularly preferably defined as a function # ( ^ ^ (so that in the discrete case the size # ^ , which is actually a function of 6, especially preferably also as a function of ^ ^ can be written). The preferred function is # ( ^ ) a Laurent series. In a preferred embodiment, the lattice spacings, i.e. the distances between the edges, are given by #(^) = ^⁄ ^ , and thus # ^ = #(^ ^ ) = ^⁄ ^ ^ (A1) In another preferred embodiment, radii ^ ^ directly given by ^ ^ = ^W^ ∙ (6 − 1) (A2) Equation (A2) is derived from Equation (A1) by treating 6 as a real variable and interpreting Equation (A1) itself as a differential equation. Its solution is then Equation (A2). For large values ​​of 6, it gives the same behavior as Equation (A1), but differs noticeably for small values, especially for 6 ≤ 10. Therefore, Equation (A2) is presented here as a separate embodiment. The dioptric power of a grating with grating constant # ( ^ ) is given by calculating the contribution ∆v ^^ ^ ^^^ ( ^ ) = ^(^) (A3) which the diffractive grating contributes to the prismatic deflection angle, as a function of ^ and as effect the derivative ^ ^^^^ (^) = ^ ^ ^ Δv ^^^^ (^) (A4) In the preferred embodiment with #(^) = ^⁄ ^ this effect is constant and is given in the diffraction order ^ at the wavelength ^ by equation (A1) with the grating parameter ^. The grating curvature @ ^ , i.e. the curvature of the cross section of the diffractive microstructure along the meridian, is given by @ ^ = @ ^ + @ ^^^^ (A5) where @ ^ is the curvature of the base curve and @ ^^^^ the diffractive curvature change that occurs due to the diffractive grating. The preferred curvature is then @ ^^^^ tailored to the effect, ie (^ ^ − ^ ^ ) @ ^^^^ = ^ ^^^^ (A6) where ^ ^ is the refractive index of the base body and ^ ^the refractive index of the outer material or the cover layer. The jump height ℎ for the diffractive microstructures, whose maximum diffraction intensity at the design wavelength ^ corresponds to the diffraction order m Max is given by ^ ℎ = ^^ ^ I^8^4^^^I^8^4^^∙ ^ ^^A ≈ I ^ ^I ^ ∙ ^ ^^A (A7) where v ^ is the angle of the beam within the body and v ^ the angle in the cover layer, and the second partial expression without cos terms of the small angle approximation at approximately normal incidence corresponds. However, if the proportion p G in the order of the basic effect m G and as much of the remaining part as possible is bent into the order of the myopia stopping power mM = mG ± 1, the jump height is calculated as A ^ ℎ = ^^ ^ ^ ^ ^4^^ ∙ -^ − ^ A I 8^4^ ^I 8 ^ E . ≈ I ^ ^I ^ ∙ -^ ^ − E . (A8) where ! is one of 3 ^ dependent number for which 56^9 / ! = 3 ^ Naturally, with this type of grid, the entire remaining portion 1 - p G be bent into the order of the myopia stopping power, because then intensity is also generally distributed among the remaining orders. If the same intensity (almost 40%) is to be distributed between the basic power and the myopia stopping power, then ℎ = ^^ ^ ^ ^^ ^ ^ ^ ^ ^^ I ^8^4^^^I^8^4^^ ∙ / ≈ I ^ ^I ^ ∙ ^ ^ / (A9) In this case, a share of about 10% ends up in the respective neighboring diffraction orders m G - 1 and m G + 2 or and m G - 2 and m G + 1. If the grid is not used for color fringing correction, then the values ​​of the radii ^ ^ (or the function # ( ^ ) ), the values ​​of the jump height ℎ and the lattice curvature @ ^independent of the base lens, i.e. in particular of the material of the lens. However, if the grating is to be used in the presence of a base lens, its effect ^ ^ is purely refractive, be adjusted to a color fringe correction, then the values ​​of the radii ^ ^ or the function # ( ^ ) , the values ​​of the jump height ℎ and the lattice curvature @ ^ preferably determined by • the refractive index ^ of the material at the design wavelength ^ • the Abbé number ^ ^ of the material • the refractive power ^ ^ of the base glass at the design wavelength ^ • the base curve @ ^ In this embodiment (full color fringe compensation) the grid parameter ^ is given by ^ = ^ | ^^| ∙ ^ ^ − ^ ) ∙ ^ ^ (A10) where the Abbé number according to (the so-called old) definition is given by ^ ^ ≔ IL^^ I ^^I^ (A11) where ^ ^ , ^) , ^ ^ the refractive indices at constant wavelengths ^ ^ = 587.5618 ^^ 656.2725 ^^ (A12) ^ ) = 486.1327 ^^. Approximately, the Abbé number is because I ^ ≔ IL^^ ^ ^ = L ^^ I(^L)^^ I ( ^^ ) ^^ ^ I ^I ( I^^I^ )⁄ ( ^^^^^ ) ∙ ( ^^^^^ ) ≈I^(^L)∙(^^^^^)≈ I^ ( ^^ ) ∙ ( ^^^^^ ) (A13) linked to the derivative ^′(^ ) of the refractive index with respect to wavelength. Since ^ according to Eq. (A2) depends on the fundamental action ^ ^ depends, the radii are a function ^ ^ ( ^ ^ ) of the counting index 6 and ^ ^ In the case of a refractive base lens, the diffractive curvature change is determined by: @ ^ ^ ^^^ = ^∙^^^^^^^∙^L∙(I^^)(A14) which makes the lattice curvature a function @ ^ = @ ^ (@ ^ , @ ^ ) of the base curve and the basic effect. For at least partial compensation of a chromatic aberration, the effect can be calculated as a function ^ ( ^, ^ ^ , Δ^ ) the wavelength and the two orders ^ ^ and Δ^, where Δ^ ≔ ^ ^ − ^ ^ is defined. If one defines the relative longitudinal color error ^^ ^^ as a derivative of the total effect S, related to the basic effect (prescription effect) ^ ^ as derivative (^⁄ ^^ ^ ^,^ ,^^ | ^^ ) ( ^ ) ^^ ^^ ≔ ^ ^ (B1) according to the wavelength ^ , evaluated at a specific design wavelength (reference wavelength) ^ , then one obtains a straight line equation ^^ ^^ = W^ + ^ (B2) as a function of the variable ^, where ^ ^ ^^ ^ ≔ ^ ^ ^^ , ^ ≔ ^ ^ (B3) and where the line parameters are given by W = ^ I^(^ ^ ) ( ) ^ ^ − I(^ ^ )^^ , ^ = I^ ^^ I (^^)^^ (B4) The longitudinal color error disappears at the zero point of the straight line equation, i.e. for ^ (^ ^ ) ^ ^ = − W ⁄ ^ = ^I^ ^^I(^ ^ )^^ ^ I^(^ ^ ) (B5) The zero itself is also a function of ^′ ( ^ )or the Abbé number. To reduce chromatic aberration, so-called MODs (multi-order diffractive structures) can be used, both in the basic power and in the myopic stopping power range. With simple diffractive structures, the diffraction orders with the greatest intensity are identical for all wavelengths. With MODs, however, the structure is designed so that different spectral ranges have their diffraction maxima in different orders. This allows dispersion to be controlled and chromatic aberration to be minimized. The structure can be designed so that the diffractive structure does not introduce any additional chromatic aberration. Preferably, the structure can also be designed so that it (additionally) compensates for the chromatic aberration of the refractive power of the basic lens, thus leading to an overall minimal chromatic aberration.Such structures can also be used in the zones for the basic power and / or the myopia stopping power. In general, the diffractive microstructures can be located either on the front or the back surface of the lens. They are preferably located on the front surface. The basic power can then be determined by the shape of the back surface using conventional technology (grinding shells) or freeform technology. Particularly in conjunction with a base curve system, the effect of the diffractive microstructures can be a defocus ("sphere") and the refractive effect of the opposing surface can have an additional defocus component and an astigmatic component ("cylinder"). This allows the rotational symmetry of the front surface to be maintained while still providing lenses with a cylindrical basic power.Of course, a cylindrical effect of the diffractive microstructures is also possible, but this requires a non-rotationally symmetric structure. The diffractive microstructures can also be protected by overcoating them with a material whose refractive index differs from that of the ophthalmic lens. This covering layer can serve both during use and during subsequent manufacturing steps (e.g., mechanical processing of the opposite surface of the ophthalmic lens) and can also be covered by further layers (e.g., hard coating, anti-reflective coating, and / or top coat). It can also serve as a hard coating itself. The diffractive microstructures can be incorporated directly into the ophthalmic lens (e.g., by machining or embossing). Alternatively, a negative of the diffractive microstructures can be molded into the mold (e.g.,by machining or embossing) and transferred into the lens during casting. Alternatively, the structure can also be introduced as a negative into a transfer layer that remains on the later lens as a protective layer (e.g., by machining, embossing, or casting), and the lens can then be cast onto this. Furthermore, one or more casting molds (with a negative structure) for the lens can be created by molding a directly structured master (with a positive structure). This can be advantageous for the following reasons: Firstly, molding is often more cost-effective than direct structuring. Secondly, materials that are well suited for direct structuring (e.g., nickel alloys) are often less suitable for casting lens materials, or vice versa (e.g., hardened crown glass). Furthermore, the structuring can be done photolithographically (e.g.,with a mask or with direct laser exposure). This applies to the ophthalmic lens itself, any transfer layer, any casting mold, and any master. Furthermore, the structures can also be created by locally changing the refractive index of the lens material inside the lens. If the structures are rotationally symmetrical, they can be created particularly easily using (precision) lathes or other rotating manufacturing systems (e.g. lasers). If the periodicity of the grating is rotationally symmetrical around the center, but not the structure height, they can also be created using (precision) lathes or other rotating manufacturing systems (e.g. lasers). However, in this case, a variation of the tool position or energy with the polar angle is required. The following are non-exclusive examples of the materials used: Materials for ophthalmic lenses: • Perfalit 1.5 (Chemical name: Polyethylene glycol bisallyl carbonate, based on CR 39 (Columbia Resin 39) from PPG, refractive index 1.5, Abbe number 58), • PCM 1.54 (Chemical name: Polyethylene glycol dimethacrylate, refractive index 1.54, Abbe number 43) • Polycarbonate (refractive index 1.59, Abbe number 29) • Perfalit 1.6 (Chemical name: Polythiourethane, refractive index 1.60, Abbe number 41) • Perfalit 1.67 (Chemical name: Polythiourethane, refractive index 1.67, Abbe number 32) • Perfalit 1.74 (Chemical name: Polythiourethane, refractive index 1.74, Abbe number about 32) Materials for transfer layers: • TS56T (3) from Tokuyama (refractive index of 1.49) • IM-9200 from SDC Technologies (refractive power between 1.585 and 1.605) • Transhade from Tokuyama (if necessary with primer (Transhade-SC-P) as adhesion promoter, refractive index 1.54) • Hi Guard 1080 from PPG Furthermore, the materials listed under materials for ophthalmic lenses can also be used for the transfer layers.Materials for casting molds: • Crown glass (for example hardened crown glass of type CH-W 0991 (S-3) from Barberini GmbH based on Schott materials) • Quartz glass (“fused silica”) • Metals (e.g. steel, nickel, nickel alloys) • Plastics (e.g. polycarbonate (PC), polyamide (PA), polymethyl methacrylate (PMMA) Materials for carrier substrates: • The materials listed under materials for ophthalmic lenses • The materials listed under materials for casting molds A preferred material combination is: Ophthalmic lens: Perfalit 1.6 or 1.67, transfer layer: Transshade, casting mold: Crown glass CH-W 0991, carrier substrate: Perfalit 1.5 In principle, a wide variety of materials are possible, such as plastics, glasses or metals, both individually and in combination. The individual materials can be layered and / or structured on the surface.

Claims

Applicant: Rodenstock GmbH "Myopia-Stop Lenses with Continuous Effect Distribution" Our Reference: R 3282 - hb / hb Claims 1. Spectacle lens, which has at least one diffractive effect zone as at least a part of a viewing area of ​​the spectacle lens such that the spectacle lens in the diffractive effect zone comprises diffractive microstructures which generate at least one basic effect or a different myopia-stop effect at each viewing point of the diffractive effect zone, wherein the diffractive effect zone comprises a combination zone in which the diffractive microstructures simultaneously generate a combination of the basic effect and the myopia-stop effect.

2. Spectacle lens according to claim 1, wherein the myopia-stop effect at each viewing point of the combination zone has a shorter focal length than the basic effect. 3.Spectacle lens according to any one of the preceding claims, wherein the 15 diffractive microstructures are arranged in a ring shape, in particular rotationally symmetrical, around a center of the spectacle lens.

4. Spectacle lens according to any one of the preceding claims, wherein the diffractive microstructures have a sawtooth shape in cross-section. 20 5. Spectacle lens according to any one of the preceding claims, wherein the diffractive microstructures have constant step heights.

6. Spectacle lens according to any one of the preceding claims, wherein the 25 basic effect and the myopia-stopping effect are each effected by a corresponding diffraction order of the light diffraction by the diffractive microstructures.

7. Spectacle lens according to any one of the preceding claims, wherein the basic power and / or the myopia stop power is generated as the zeroth diffraction order of the diffractive microstructures.

8. Spectacle lens according to any one of the preceding claims, wherein the diffractive microstructures exhibit at least substantially a simple periodicity for each viewing point of a plurality of viewing points within the combination zone, wherein the basic power and the myopia stop power are effected by different diffraction orders of a diffraction grating formed thereby.

9. Spectacle lens according to claim 8, wherein the respective diffraction orders of the basic power and the myopia stop power differ from each other by 1. 10.Spectacle lens according to any of the preceding claims, wherein the diffractive microstructures for each viewing point of a plurality of viewing points within the combination zone comprise: - a first diffractive substructure that essentially generates the basic effect; and - a second diffractive substructure that essentially generates the myopia stopping effect.

11. Spectacle lens according to claim 10, wherein the first substructure is formed by a first periodic diffraction grating with a first grating period and a first grating amplitude, and wherein the second substructure is formed by a second periodic diffraction grating with a second grating period and a second grating amplitude.

12. Spectacle lens according to claim 11, wherein the first grating amplitude and the second grating amplitude differ from each other, while preferably the first and second grating periods are essentially the same. 13.Spectacle lens according to claim 11, wherein the first lattice period and the second lattice period differ from each other, while preferably the first. and the second lattice amplitude substantially coincide.

14. Spectacle lens according to any one of claims 11 to 13, wherein the diffractive microstructures comprise a plurality of first substructures and a plurality of second substructures, each arranged alternately with respect to the other.

15. Spectacle lens according to claim 14, wherein along a continuous path within the combination zone, a number of the first lattice periods of the first substructures and a number of the second lattice periods of the second substructures change successively in opposite directions.

16. Spectacle lens according to any one of claims 11 to 15, wherein the number of lattice periods in each substructure is in the range of about 2 to about 200, preferably in a range of at least about 5, more preferably at least about 10; and / or in a range of not more than about 100.

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