TR2023001840T2 - REGIONAL DIFFRACTIVE EYE LENS - Google Patents

Abstract

The invention relates to a multifocal ophthalmic lens containing at least three focal points, and this lens has a light-permeable lens body. It includes at least a first portion having a first crushing base force and a second portion having a second crushing force coinciding with the central area thereof, the first portion and the second portion being concentrically disposed. The first part is a single focal area that provides distance vision. The multifocal ophthalmic lens also includes a multifocal symmetrical network combined with the second part, this multifocal symmetrical network is a periodic uniform sinusoidal network in the field r2, the orders of which are symmetrically located around the 0th order.

Description

DESCRIPTION P6018 REGIONAL DIFFRACTIVE EYE LENS TECHNICAL FIELD OF THE PRESENT INVENTION The present disclosure relates generally to ophthalmic lenses and more specifically to ophthalmic spectacles, ophthalmic ocular contact and intraocular multifocal lenses, where multifocality is achieved by the combination of the diffraction zone(s) and the refractive zone(s). BACKGROUND OF THE PRESENT INVENTION Diffractive lenses for ophthalmological applications are hybrid lenses that contain a diffractive pattern attached to a refractive body. Often one side of the lens is just refractive, while the other side has a diffraction grating superimposed on a refractive baseline. The refractive baseline may be spherical or, alternatively, may have some form of non-spherical shape. The diffractive pattern is superimposed on the refractive baseline. The diffractive part can generally be applied to either side of the lens, because if a diffractive pattern is to be combined with a refractive surface having some unique properties, it makes essentially no difference whether they are attached to the same side or whether one is attached to a first side of the lens and the other to a second side. Also, two diffractive patterns may be combined by superimposing them on one side or by adding them to separate sides so that they overlap. The optical power of the lens for a specific diffraction range can be calculated by adding the refractive base power and the optical power of this diffraction order. It should be noted that a diffraction grating functioning as a lens contains a range that varies with radius in absolute terms. The range depends on the refractive index, design wavelength, and first-order optical power. The spacing is determined so that there is a difference of exactly one wavelength per period in the light path difference (OPD) from the lens to the focal point of the first order of diffraction. To show the periodicity of the diffraction grating, a diffractive lens profile graph is often drawn according to the square of the radius. When plotted in this way, the periods (net spacing) are equidistant, more specifically the period spacing in the r2 field is 2A/D, where A is the design wavelength and D is the optical diffraction power of the first order in diopters. The term diffractive lens is sometimes used for the well-known Fresnel lenses. A Fresnel lens consists of concentric zones with vertical gradients at the zone transitions. The zones in Fresnel Lenses are often of equal width, and the optical properties of each zone can be analyzed through refractive theory. However, the diffractive lenses discussed here are lenses that require diffraction analysis. The most researched type of diffractive lens is the phase-coherent Fresnel lens, as taught in the 1995 study titled "Refractive and diffractive properties of planar micro-optical elements" by Rossi et al. This type of lens uses a sawtooth-shaped diffraction unit cell and a stage height corresponding to a phase modulation of exactly 21T. In the phase-coherent Fresnel element design, planar microlenses show both refractive and diffractive behavior, adjustable by the phase matching number M,- for each diffraction zone. A high MJ- increases the height and width of the region of interest. All the energy in such a lens goes to the first order, for each Mj equals 1, all the energy goes to the first order, which means these are single focus diffractive lenses. Of course, the only diffractive form that is 100% efficient is the sawtooth profile, which has the entire modulation of the design wavelength, meaning that the vertical jump at the zone transitions corresponds to a phase delay that is an integer multiple of the number of wavelengths. It is often desired to provide more than one focal point. For ophthalmic lenses, it can often be convenient to provide simultaneous distance vision and near vision, for example. To provide two focal points, the most light-efficient lens possible uses a sawtooth profile similar to the phase-coherent Fresnel described above but with lower height. The highest possible diffraction efficiency for such a lens is close to 81%. For diffractive lenses optimized for more than two focal points, sawtooth-shaped patterns are not the most efficient, and higher diffraction efficiencies are possible, as explained below. In recent years, lenses that provide three separate focal points, often distance, intermediate and near vision, have become widespread. The majority of diffractive trifocal ophthalmic lenses use sawtooth-shaped profiles. It is known in the art to combine the sawtooth-shaped profiles of two bifocal diffractive lenses to obtain trifocality. This process provides diffractive lenses whose usable orders are located asymmetrically with respect to the O. order, for example, in a trifocal lens, 0, +1 and +2 lenses are described, where the optical thickness of the surface profile varies monotonically with the radius within each region, at the transition between neighboring regions. A separate stage defines a step height. In order to adapt the diffraction efficiency of the optical element, the step heights for the relevant regions may vary periodically between regions, where the step heights may alternate between two values. In EP 2,377,493, a method of manufacturing an aphakic intraocular lens is proposed, which can more safely provide each multifocal effect while reducing the effect of aperture variations and lens eccentricity. EP 2,503,962 discloses an intraocular lens comprising an anterior surface and a posterior surface and having a substantially anteroposterior optical axis, wherein one of these anterior and posterior surfaces produces at least one first diffraction of order +1 on this optical axis. a first diffraction profile forming a focal point and a second diffractive profile forming at least a second diffraction focal point of order +1, the two diffraction focal points being separate and at least a portion of the second diffractive profile superimposed on at least a portion of the first diffractive profile. US 9,223,148 recommends a lens with more than two powers, at least one of which is refractive and one of which is refractive. In US 5,017,000 a phase plate with a multifocal profile is proposed, comprising a plurality of spaced annular concentric zones according to the formula r(k) = square root(constant x k), where r(k) is the zone radius and k is a zone; Here, a repeating stage with an optical path length of more or less than half a wavelength is included in this profile. In EP3.435.143, one of the prior art publications that can be cited within the technical field of the present invention, a multifocal diffractive ophthalmic lens containing focal points for near, intermediate and distance vision is taught. This lens includes a light-transparent lens body providing a refractive focus point and a periodic light-transparent diffraction grating that extends concentrically along at least a portion of the surface of the lens body and provides a series of diffraction focus points. The diffraction grating functions as an optical wave splitter, the diffraction focal point provides the focal point for intermediate vision, and the diffraction focal points provide focal points for near and far vision. There is a phase profile in the diffraction grating that changes the phase of the incident light in the lens body in such a way as to optimize the overall efficiency of light distribution at the refractive and diffraction focal points. The orders of this lens are located symmetrically around the 0th order and function at least in the -1, 0 and +1 orders. For example, diffractive lenses with sharp transitions in the diffractive profile, including sawtooth-shaped profiles and dual-profile lenses, cause machining difficulties and cause glare for a finished lens in the presence of diffuse light, i.e. bright light, such as direct or reflected sunlight, or artificial lights such as car headlights at night. They lead to increased occurrence of many undesirable optical phenomena and light scattering, such as visual difficulties and halo effects, that is, white or colored light rings seen in low light, in other words under mesopic conditions. Diffractive lenses without sharp transitions perform better with respect to these problems and have higher potential diffraction efficiency, at least for multifocal lenses with a single number of focal points. As explained by Osipov et al. in 2015 in the study titled "Journal of biomedica/ fabrication of trifocal diffractive lens with sine-like radial profile", sinusoidal or smooth diffractive profiles are more biocompatible than sawtooth-shaped profiles due to the lower residual sedimentation effect. The distribution of light at the focal points of an ophthalmic lens with usable orders located symmetrically around the forward diffraction grating and O. order is determined by the argument of the phase profile function and its amplitude as either or both a function of the radius of the lens body or a function of the radial distance to the optical axis of the lens body. It is known that it can be adjusted over a relatively wide range of intensity by modulation. In recent years, a general approach to making a lens known in the art, including a three-focal lens operating in the -1, 0 and +1 ranges, has also been introduced in US 5.017. It is known from the teachings of 000. The resulting diffractive lens is a diffractive lens that functions in the 0, +1 and +2 ranges. This can be done by starting from a linear phase network optimized for equal light distribution and diffraction efficiency. Linear phase networks have been researched and developed to create beam splitters. The general theory on the optimization of linear phase networks was published in 2007 by Romero and Dickey in "Theory of optimal beam splitting by phase gratings. l. It is taught in the work titled "One-dimensional gratings". The existing literature on diffraction phase networks is focused on finding the optimal solution for the case of equal intensity distribution among a certain number of orders, that is, the maximum diffraction efficiency. For the reasons given above, both positive and negative diffraction orders are used. It is often convenient to use multifocal, hybrid lenses utilizing uniform diffraction gratings. However, such prior art lenses have many limitations. After implantation of an intraocular lens in the human eye, the new focusing qualities of the eye as a whole must be measured. In practice, most physicians rely on a simple measurement with an automatic refractometer as a primary target indicator of the outcome of the visual system, consisting of the new lens and the rest of the wearer's eye. gives focus. For lenses with sinusoidal diffraction patterns throughout the lens optics, automatic refractometers and some combinations of lenses can provide the power of the refractive base, which often does not have the same optical power as distance vision. Other combinations of automatic refractometers and sinusoidal diffractive lenses provide a power between the power of the refractive base and the power of one of the refractive powers. Although protocols exist to measure entire intraocular lens foci, the implementation of such protocols is often perceived as too time-consuming. In general, in diffractive multifocal lenses with asymmetric gratings, the height of the grating can be reduced to increase the density of the refractive focal point. This process can be used in sawtooth diffraction gratings to enhance one of the outermost diffraction orders relative to all the other orders, which can sometimes be advantageous. A frequently desired characteristic of multifocal lenses is to provide a relatively even density distribution for mesopic conditions while providing much stronger relative intensity for distance vision for the larger pupils present in scotopic conditions. In sawtooth-shaped multifocal diffractive lenses, this is often achieved by adaptation, which in this context refers to diffraction gratings where the radius is increased and the height is reduced, as taught in the Journal of M. J. Simpson's "History and development of the apodized diffractive intraocular lens." For a lens using a uniform sinusoidal mesh, this simple method cannot be used for this purpose. Lenses derived from an established linear phase network are disclosed. In this case, the intensity distribution is fine-tuned by laterally shifting the diffraction grating along the radial direction. However, the current state of the technology does not allow the use of lenses using smooth sinusoidal gratings with higher diffraction efficiency than this. An underlying reason for this is that when gratings with very high diffraction efficiencies are used in well-known configurations, they entail undesirable intensity distributions. Once a multifocal intraocular lens is implanted, there is always an adjustment period before the user fully appreciates the advantages of the lens. This is due to adaptation processes in the user's eyes and also in his brain. Clinical observations show that after implantation, users first adapt to distance focus and, for a multifocal lens, eventually adapt to two additional focal points, namely near and intermediate focus, within a few days or weeks. However, in a lens center that is fully optimized for multifocality for all pupil sizes, the accommodation time for distance focus also increases. This may be unpleasant and disturbing for some users. There is therefore a need for an improved ophthalmic lens that takes advantage of uniform sinusoidal diffraction gratings but solves the prior art limitations of such lenses, in particular by combining the relative intensities of three or more diffraction orders or focal points to provide significantly different intensity ratios for different aperture sizes. It enables lens designs that provide greater freedom in adjusting and controlling, offer the ability to easily measure the diffraction focal point, improve a user or patient's adaptation time, and improve the ability to utilize diffraction gratings with very high diffraction efficiency. OBJECTIVES OF THE PRESENT INVENTION The primary object of the present invention is to provide a multifocal ophthalmic lens containing at least three focal points, one of which provides distance vision. Another object of the present invention is to provide a multifocal ophthalmic lens comprising at least a first and a second part providing a first and a second refractive optical power, respectively, and these parts are arranged concentrically. A further object of the present invention is to provide a multifocal ophthalmic lens comprising a symmetrical diffraction grating providing at least three focal points when combined with the first part, the O. order of this diffraction grating being added to the optical power of the first part for the design wavelength. A further object of the present invention is to provide a multifocal ophthalmic lens comprising a symmetrical diffraction grating such that one of the non-Oth order diffraction orders of the diffraction grating is added to the refractive optical power of the second part. A further object of the present invention is to provide a multifocal ophthalmic lens wherein the refractive base powers of the first and second parts are different and at least one of the two has a sawtooth-shaped diffraction grating with an arbitrary height. It is another object of the present invention to provide a multifocal ophthalmic lens with optimized multifocality wherein the diffraction efficiency is greatly improved. In a first aspect, a multifocal ophthalmic lens is provided which includes at least one focal point for distance vision. This lens has a light-transparent lens body, which includes a symmetric (i.e., optical powers are symmetrically aligned about 0.000 order) diffraction grating extending concentrically across a portion of the lens body surface in the radial direction from the optical axis of the lens body. The lens includes at least a first and a second part, each part having a different refractive baseline and each part providing a refractive optical power different from that of any other part, the parts being concentrically arranged and the arrangement of a symmetrical diffraction grating on the first part. , for the design wavelength, at least two of the focal points of the diffraction grating are such that they coincide with and receive contribution from the refractive power of the two parts. Assume an lens with a structure that provides a target focal point for near vision at +1 diffraction order, a target focal point for distance vision at -1 diffraction order, and a target mid-refraction focal point, also referred to as 0 (zero) order. For example, when the focal point of the monofocal peripheral portion coincides with the target focal point for distance vision, this provides the ophthalmologist with a lens portion that can be measured unambiguously. The present invention enables very different intensity distributions for different pupil sizes without the need for any diffraction pattern with sharp edges, as in sawtooth or binary diffraction profiles. On the contrary, lenses according to the invention can provide three or more foci for photopic and mesopic conditions with higher diffraction efficiency than is possible, for example, when using asymmetric diffraction gratings combined with the very strong distance vision provided in scotopic conditions. A typical automatic refractometer measures around the patient's pupil. However, an ophthalmologist often takes measurements in light conditions that cause the pupil to be approximately 3 mm in diameter. If, for example, in a 3mm diameter pupil, the multifocal central part of a lens according to the present invention is 2.3mm in diameter, an automatic refractometer of the said type gives the refractive power provided by the peripheral part. According to the present invention, the lens body includes a first part having a monofocal central region providing distance vision, extending for a distance in the radial direction from the optical axis of the lens body along a portion of the lens body surface, and a second part having a symmetrical diffraction grating with high diffraction efficiency. . The present description is that by providing a multifocal periphery and a monofocal center with high diffraction efficiency in the ophthalmic lens, a focal point coinciding with one of the diffraction focal points provided by the diffraction grating, the ease of accurate in vivo measurements of the distance vision of the lens is improved, allowing users to focus on the distance focus. It is based on the predictions that adaptation time is shortened and useful and practical designs with very high diffraction efficiencies are enabled in the underlying linear diffraction grating, as the strong far vision of the central part can balance the weaker diffractive far vision in a high efficiency grating. The target focal point for near vision at +1 diffraction order, Assume a lens with a structure that provides a target focal point for distance vision at -1 refraction order and a target mid-refraction focal point, also specified as 0 (zero) order. For example, when the focal point of the single-focal central portion overlaps the target focal point for distance vision, the adaptation of the combination of the patient's visual system, side, lens, and eye to the targeted distance vision can be measured for pupil sizes close to the size of the single-focal central portion. A typical automatic refractometer measures around the patient's pupil. However, an ophthalmologist often takes measurements in light conditions that cause the pupil to be approximately 3 mm or less in diameter. A typical pupil size when measuring a lens manufactured according to the present invention is approximately 1mm to 2mm. Therefore, with such dimensions, the person making the measurement knows that the measurement gives a result based on the focal point of the single-focus central region. Furthermore, with the present disclosure, a strong distance or near focus provided by the single-focus central zone can be achieved for a wide range of pupil sizes. In outdoor and/or daytime conditions, far or near focus is dominant. Compared to multifocal lenses known in the art, this provides a faster adaptation time for the focus provided by the single-focus central zone and a more comfortable experience until the user's visual system accepts all of the focuses. As mentioned above, in the absence of concentric rings or zones with sharp edges, no Lenses with a continuous, smooth profile without sharp edges are less prone to haloing and scattering or flare caused by irregularities in the path of incident light through the lens, as well as being easier to fabricate to a calculated profile than meshes or reliefs, such as sawtooth or binary types. . In any case, a higher diffraction efficiency leads to less scattered light. Due to production technologies based on diamond turning or similar machining methods, a smooth profile is more reliable, faster and cheaper than profiles with sharp edges such as sawtooth or double profiles. An important step in the production of ophthalmic lenses, for example by micromachining or diamond turning, is mechanical polishing to remove cutting marks. To comply with quality requirements and medical regulations for intraocular lenses, all visible cut marks must be removed. However, achieving extremely low levels of cutting marks requires expensive machinery along with slow cutting. If the lenses are polished after cutting, the machine can work faster. Sharp angles, corners or edges in the height profile of diffractive lenses make mechanical polishing difficult. If mechanical polishing is not possible due to the height profile of the lens, it is necessary to use chemical polishing, which requires hazardous chemicals, or to produce lenses without the need for polishing. Manufacturing lenses without the need for polishing results in very high manufacturing costs due to lower efficiency, more expensive machinery, or both. Uniform diffraction geometries according to the present invention allow polishing and, therefore, a significant increase in efficiency relative to lenses with sharp transitions in height profiles. The present invention aims to teach combinations of certain types of gratings and zones with different refractive base power, providing technical results associated with the improvement of the disadvantages noted in the prior art. . Considering the uncertainties of the measurements performed on the lenses, the teachings of the present invention provide lenses with monofocal parts located concentrically with respect to each other and multifocal parts located symmetrically around the 0th order. The teaching of the present invention also provides multifocal lenses containing a wider range of intensity distribution profiles, in particular lenses having a wider difference in intensity distribution between different apertures. To address this, lenses with strong multifocality are recommended for small apertures (e.g., photopic and mesopic conditions) but with larger pupils, i.e., distance-view dominant for scotopic vision. Another proposal of the present invention is a type of lens with single-focus central portions and peripheral portions containing a highly efficient diffraction grating. DETAILED DESCRIPTION OF THE PRESENT INVENTION Eye 12 Pupil 14 Retina Posterior space 16 Anterior and posterior chamber 17 Distance vision 18 Intermediate vision 19 Near vision Optical axis 29 Optical axis Ophthalmic lens 31 Lens body 32 Haptic(s) 33 Center piece 34 Anterior surface Rear surface 36 Diffraction grating 37 Optical diameter 38 External diameter 39 Center thickness 40 Lens 41 Lens body 42 Diffraction grating 43 DOE(s) 44 Light receiving surface 45 Center piece 46 Primary light beam 47 Secondary light beam 48 Optical axis 50 Multifocal aphakic intraocular lens 51 Central lens part 52 Symmetric multifocal reticle 53 Peripheral lens part 60 Baseline curvature 61 Height profile 62 -1 diffraction order 63 +1 diffraction order 64 O diffraction order 70 Baseline curvature 71 Height profile 72 Light intensity distribution 73 -1 diffraction order 74 +1 refraction order 75 O refraction order Sawtooth shaped profiles are used in the majority of diffractive trifocal ophthalmic lenses. It is known in the art to combine the sawtooth-shaped profiles of two bifocal diffractive lenses to obtain trifocality. This process provides diffractive lenses whose usable orders are asymmetrically located with respect to the 0th order, for example, a trifocal lens may use 0, +1 and +2 orders or 0, +2 and +3 orders. From here on, such diffraction gratings are referred to as asymmetric gratings. For diffractive trifocal lenses, the highest possible diffraction efficiency for the most useful intensity distribution is achieved by smooth sinusoidal surfaces whose usable ranges are symmetrically located around the 0th order. The orders of such a lens are located symmetrically around the 0th order and it functions at least in the -1, 0 and +1 orders. From here on, networks containing this arrangement of available orders are referred to as symmetric networks. An important element in comparing diffraction surfaces is diffraction efficiency. Diffraction efficiency is a measure of how much of the optical power is directed to the desired diffraction ranges or, especially in the case of diffractive lenses, how much of the optical power is directed to the desired focal points. As for bifocal lenses, the highest possible diffraction efficiency is achieved using the principles of a phase-coherent Fresnel lens using a sawtooth or notched type diffraction grating, if the lens body surface is optimized to provide as good a view as possible at two separate distances. Reference is made to the publication "Refractive and diffractive properties of planar micro-optical elements" by M. Rossi et al. Fresnel lenses have all the disadvantages described above, in particular regarding flare and halos as a result of discontinuities in the diffraction profile, due to the sharp edges of the sawtooth-shaped or jagged type of diffraction pattern, in addition to the difficulty of manufacturing such structures with high precision. However, as a trifocal lens, the most suitable mesh for lenses that provide the best possible vision to three separate focal points is the mesh that does not contain any sharp edges. It is often convenient to consider the linear phase network first, because this field contains well-developed theory and can be used for diffractive lenses. As for the original case of a three-focus linear phase network with equal density distribution to each order, it has been specifically shown in the publication "Analytical derivation of the optimum triplicator" that the optimal solution is a structure without sharp edges, which is included here by reference, Journal of Optical Society of America volume 24, issue 8 (2007) p. In the publication "Theory of optimal beam splitting by phase gratings. l. One-dimensional gratings" by L. A. Romero and F. M. Dickey, published in 2280-2295, this situation is explained more generally and, at least, for splitting equal to an odd number of orders. It proves that there are persistent profiles in suitable networks. This final work provides the mathematical tools to find any given set of target orders and any given density distribution among those target orders. The optimal grating is defined as the linear diffraction grating with the highest diffraction efficiency for the specified intensity distribution. It should be noted that the publications by Gori et al. and Romero et al. discuss linear phase networks only with respect to beamsplitters. According to the present invention, a lens such as an intraocular lens is proposed, more specifically, a multi-zone multifocal intraocular lens that can correct vision errors for a variety of human eyes with different corneas under a wide range of light conditions and perform in different orientations. The lens according to the present invention is an intraocular lens comprising at least a first and a second part, wherein each part has a different refractive baseline and each part provides an optical power that is different from the optical power of any other part. In one embodiment, at least a first and a second part are arranged concentrically; The first part contains a symmetrical diffraction grating, one of whose (non-0th order) diffraction orders essentially coincides with the optical power of the second part. In Figure 1, the anatomy of the human eye (10) is shown in a simplified form in order to illustrate the present invention. The cornea (11), which is a sphere-shaped transparent tissue covering the pupil (12), forms the front part of the eye (10). The pupil (12) is the adaptive light receiving part of the eye (10) and controls the amount of light received into the eye (10). The light rays passing through the pupil (12) are received in the natural crystal lens (13), which is a small, transparent and flexible disc inside the eye (10) that focuses the light rays on the retina (14) at the back of the eye (10). The retina (14) functions in the image formation of the eye (10). The posterior space (15), that is, the area between the retina (14) and the lens (13), is filled with vitreous body, which is a clear, jelly-like substance. The anterior and posterior chambers (16), that is, the area between the lens (13) and the cornea (11), are filled with eye fluid, which is a clear, watery fluid. The reference number (20) indicates the optical axis of the eye (10). In order to obtain a sharp and clear far-field vision with the eye (10), the lens (13) must be relatively flat; in order to obtain a sharp and clear near-field vision, the lens (13) must be relatively curved. The curvature of the lens (13) must be controlled by the ciliary muscles ( not shown), the ciliary muscles are also controlled by the human brain. A healthy eye (10) can adapt in front of the cornea (11) to provide a clear and sharp image of images at any distance between the far field and near field, that is, it can control the lens (13). Ophthalmic or artificial lenses are applied together with the lens (13) to correct the vision of the eye (10), in which cases the ophthalmic lens is positioned in front of the cornea (11) or is applied to replace the lens (13). Lens replacement is also referred to as aphakic ophthalmic lenses. Multifocal ophthalmic lenses are used to improve or correct the vision of the eye (10) at various distances. For example, in the case of trifocal ophthalmic lenses, the ophthalmic lens provides room for sharp and clear vision at three or more separate distances or focal points, often including distance, intermediate and near vision, designated by reference numerals 17, 18 and 19, respectively, in Figure 1. gets. In optical terms, distance vision is when the incoming light rays are parallel or close to parallel. The light rays emitted from objects located at these distances or focal points 17, 18 and 19 or around them are focused correctly on the retina (14), meaning that clear and sharp images of these objects are reflected. In practice, focal points can correspond to focal distances ranging from a few meters to tens of centimeters, 17, 18, and 1910 centimeters, respectively. Ophthalmologists often choose lenses for patients so that the far focus allows the patient to focus on parallel light, which in common optical terminology means focusing on far infinity. When testing patients, ophthalmologists commonly measure near vision at a distance of 40cm from the eyes and intermediate vision at a distance of 66cm, but other values may also be used. The amount of correction provided by an ophthalmic lens is called optical power OP and is expressed in diopters D. Optical power OP is calculated as the reciprocal of the focal distance f measured in meters. That is, OP = 1/f, where f is the relative focal distance from the lens to a corresponding focal point for far (17), intermediate (18) or near vision (19). The optical power of a series of lenses is found, for example, by adding the optical powers of the lenses that make up this series. The optical power of a healthy human lens (13) is approximately 20 D. Figure 2a shows the top view of a typical multifocal ophthalmic aphakic intraocular lens (30), and Figure 2b shows the side view of this lens (30). The lens (30) includes a light-permeable circular disc-shaped lens body (31) and a pair of haptics (32) extending outward from the lens body 31 to support the lens (30) in the human eye. It should be noted that this is an example haptic and there are many known haptic designs. The lens body (31) is disvex on both sides and includes a central part (33), an anterior or anterior surface (34) and a back or posterior surface (35). The lens body (31) also includes an optical axis (29) extending transversely to the front and rear surfaces (34, 35) and from the center of the center piece (33). The skilled worker will appreciate that the optical axis 29 is a virtual axis for purposes of reference to the optical qualities of the lens 30. In a practical embodiment, the convex lens body (31) provides a refractive optical power of approximately 20D. In the embodiment shown, a periodic light-permeable diffraction grating or relief (36) is located on the front surface (34) of the lens body (31), which indicates that the lens body (31) It consists of rings or regions extending concentrically according to the optical axis (29) through the central part (33) along at least one part of the front surface (34). The diffraction grating or relief 36 provides a series of diffraction focuses. Although not shown, the diffraction grating or relief 36 may also be located on the rear surface 35 of the lens body 31 or on both surfaces 34, 35. In practice, the diffraction grating 36 is not limited to concentric circular or annular ring-shaped regions, but includes, for example, concentric elliptical or oval-shaped regions, or in general any type of concentric ring-shaped regions. In practice, the optical diameter 37 of the lens body 31 is about 5mm to 7mm, the thickness of the haptics 31 39 can be about 1mm. In the case of multifocal ophthalmic contact lenses and spectacle lenses, there is no haptic (32) in the lens body (31), and the lens body (31) has a shape that is flat on one side and convex on the other side, concave on two surfaces, or flat on one side and concave on the other face, or convex and may include combinations of concave shapes. The lens body may comprise any of hydrophobic acrylic, hydrophilic acrylic, silicone materials, or, in the case of an ophthalmic aphakic lens, any other light-permeable material suitable for use in the human eye. In Figure 3, the optical operation of a known periodic light-transmitting diffraction grating or relief (42) of a lens (40) comprising a light-transmitting circular disk-shaped lens body (41) convex on two faces is shown schematically. This type of lens, which combines refractive and diffraction power, is also called a hybrid lens. The lens 40 is seen in a cross-sectional view in the radial direction of the lens body. The diffraction grating or relief 42 contains many repeating, adjacent, prism-shaped transparent diffractive optical elements (DOE) 43. DOEs 43 extend in concentric regions around the center piece 45 of the lens body 41, similar to the rings or regions of the mesh or relief 36 seen in Figure 2a. For illustration purposes, the DOEs 43 of the diffraction grating 42 are viewed as well-known notched or sawtooth type elements containing a continuous, inclined light receiving surface 44, such as a linear or curved inclined light receiving surface 44. Networks or reliefs in which the DOEs 43 alternate between two heights spaced apart in the radial direction of the lens body 41 are called dual type reliefs (not shown). The repetition period or interval of the DOEs 43 decreases monotonically in the radial direction from the center or optical axis of the lens and varies with the square of the radial distance. The range depends on the refractive index, design wavelength, and first-order optical power. The spacing is determined so that there is a difference of exactly one wavelength per period in the optical path difference (OPD) through the lens to the focal point of the first order. To visualize the periodicity of a diffraction grating, the diffractive lens profile is often plotted versus the square of the radius. When plotted in this way, the periods (net spacing) are equidistant, more specifically the period spacing at r2 is |2/1f|, where A is the design wavelength and f is the reciprocal of the optical power of the first order of diffraction. In the technique, one side of the lens is purely refractive, while the other side has a diffraction grating superimposed on the refractive baseline. The crusher baseline may, for example, be spherical or some form of non-spherical shape. The diffraction pattern superimposed on the refractive baseline can generally be applied to either side of the lens. Therefore, if a diffraction pattern is to be combined with a refractive surface with some unique characteristics, it is usually of little importance that they are added on the same side, or that one is added to the first side of the lens and the other to the second side. Also, two diffraction patterns can be combined by superimposing them on one side or by superimposing them on separate sides. In the descriptions of the present invention, the combination of two lens structures should always be understood as allowing both possibilities. The optical power of a lens for a given diffraction range can be calculated by adding the refractive base power and the optical power of this diffraction order. An incident or primary light beam (46) passing through the network (42) and the lens body (41) is respectively diffracted and refracted, resulting in an incident or secondary light beam (47). Secondary light beams (47), that is, refracted and diffracted light waves, create many focal points on the optical axis (48) of the lens (40) as a result of the constructive interference of the secondary light beams (47). Constructive interference occurs when the optical path difference between the secondary light beams (47) reaching the lens body (41) at a certain focal point is an integer multiple of their wavelengths, that is, the light waves are in phase, so their amplitudes are additively additive. When the difference in the optical path length that the interfering light waves (47) travel from the lens body (41) is an odd multiple of half the wavelength, the peak of one wave meets the bottom point of another wave and the light waves (secondary light beams 47) partially or partially destroy each other. They suppress completely, that is, the light waves are out of phase and focal points are not formed on the optical axis (48) of the lens body (41). Constructive interference points at various distances from the lens body (41) are generally determined diffraction orders. The focal point corresponding to the focal point resulting from the refractive function of the curvature of the lens (40) is indicated by the zero order 0. Other focal points are specified by orders +m and -m, where m is a positive integer value. That is, if the relevant focal point appears on the left side of the zero range when viewed from the drawing plane, that is, when viewed from a distance in the direction of the Iens body 41, m = +1, +2, +3, etc., and if the relevant focal point is viewed from the drawing plane , that is, if it appears on the right side of the zero range when viewed from a distance in the opposite direction to the lens body 41, m = -1, -2, -3, etc. are indicated by their ranks. This situation can be seen, for example, in Figure 3. It should be noted that the above ordering of positive and negative diffraction orders may be reversed in some publications and manuals due to their position relative to the zero order. This occurs, for example, when the theory in Romero et al.'s publication is applied directly, as is done here. Unless otherwise stated, the present disclosure follows the scheme seen in Figure 3. The diffraction relief (42) may have a structure that provides focal points at different distances from the lens body (41). The periodic distance or spacing of the DOEs (43) essentially determines the locations where destructive and constructive interference points occur on the optical axis (48) of the Iens, that is, the positions of the diffraction orders on the optical axis (48). The amount of incident light provided at a constructive interference point, that is, at a given diffraction order, is controlled by the shape and height of the DOEs (43). In the case of a diffraction grating or relief (42) that provides regularly spaced diffraction orders on both sides of the zero order, this grating or relief is called a symmetric wave splitter or diffraction grating, since the incident light beam (46) is located symmetrically with respect to the zero order. It is diffracted or divided into different levels. A grating or relief that forms a non-regular spacing of diffraction orders such as +1, +2, -3, -5 is called an asymmetric diffraction grating. Common cases of diffraction gratings that form usable orders at 0th order and +1 or at 0th, +1 and +2 are asymmetric diffraction gratings. The light energy in the secondary light beams (47) that are focused or refracted at focal points or levels that do not contribute to image formation on the retina (14) of the human eye (10) is lost and reduces the total efficiency of the lens (40) and therefore the quality of images perceived by a human using such a lens. In practice, for the sake of the most suitable lens design, it is convenient to pre-adjust the focal points, for example, to provide or correct distance, intermediate and near vision to the human eye, as seen in Figure 1, and to use the light energy received from the light beam (46) at these pre-set focal points. It is most appropriate to provide a diffraction grating 42 that maximizes the overall efficiency. In the scientific literature, a diffraction grating that optimizes the overall efficiency of light distribution in preset or target diffraction orders is a linear phase-only function or phase profile that creates target diffraction gratings with a maximum total efficiency ri or coefficient of performance defined as the sum of the normalized light energies of all of these target orders. It is found from the determination. These diffraction gratings can then be shaped into Iens by setting the argument so that they have equidistant periods in the r2 field. The skilled artisan will appreciate that the Iens body 41 may include a shape that is flat on one side and convex on the other, concave on two faces, or flat on one side and concave on the other, or combinations of convex and concave shapes or curves (not shown). Figure 4a shows the top view of a multifocal ophthalmic aphakic intraocular lens (50) that functions in accordance with the present technique, and Figure 4b shows the side view of this lens (50). The difference compared to the previous technique, seen in Figure 2, is the optics of the lens. The lens body (56) is disvex on both sides and includes a front or anterior surface (54) and a back or posterior surface (55). The skilled artisan will recognize that in some embodiments, one or both of the front surface 54 and the rear surface 55 may be concave or planar, depending on the refractive baseline needed for a specific application. In this embodiment of the invention, the lens body, according to the present description, includes a central lens part (51) and a peripheral lens part (53) combined with a symmetrical multifocal diffraction grating (52). The refractive powers of the central lens part (51) and the peripheral lens part (53) are different. The structure of the lens is such that, for the design wavelength, one of the diffraction orders of the symmetrical multifocal diffraction network (52) contributes to the refractive focal point of the central lens part (51). Figure 4 shows a lens that is refractive only on one side and has a diffraction grating superimposed on the refractive baseline on the other side. As explained above in relation to Figure 3, this is just one of the structures. For example, it is possible to distribute the diffraction grating on both sides, or to superimpose the diffraction grating on any side of the lens, flat on one side and convex on the other, or flat on one side and concave on the other. The shape or height profile of the refractive baseline for any of the lens sections may be selected from among the many continuous refractive profiles known from single-focus lenses, such as spherical shape, or based on the single-focus diffraction surface, or aspherical surfaces, which are among the most common forms of single-focal lenses known in the art. . With single-focal diffraction surfaces, reference is made to phase-coherent Fresnel lenses discussed above. By adjusting the number of phase coherences, an arbitrarily large continuous single-focal region can be created via diffraction optics. It is possible to combine different types of refractive surfaces in a single lens, so that the central part and the peripheral part consist of different types of refractive surfaces. The production of fracture or diffraction surfaces can be accomplished, for example, by laser micromachining, diamond turning, BB printing, or any other machining or lithographic surface treatment technique. Figure 5 shows a single-focus diffractive lens operating in the first order. From these images, in Figure 5a, the diffraction profile is seen as it really is, and in Figure 5b, the lens graph is drawn according to the square of the radius, so that the periodicity in the r2 field is clearly visible. Profile height H(r) is shown on the vertical axes. Generally, for first-order diffractive lenses, the spacing is determined so that there is exactly one wavelength difference in optical path difference (OPD) from the lens to the focal point of the first order of diffraction. To illustrate the periodicity of a diffraction grating, one often plots the diffractive lens profile versus the square of the radius (often referred to as the r2 area), as here. When plotted in this way, the periods (net spacing) are equidistant, more specifically the period spacing in the r2 field is 2A/D, where A is the design wavelength and D is the optical diffraction power of the first order in diphthongs. The lens in Figure 5 is a first-order monofocal lens, this is achieved by using a sawtooth-shaped diffraction unit cell and a stage height corresponding to a phase modulation of exactly 21T (two pi or two times pi). All of the energy in this type of lens goes to either +1 order or -1 order, depending on the definition. This is the only type of diffraction grating with 100% diffraction efficiency. By setting the phase matching number to m, the height of each region in the r2 field is increased to m21T, and the width of each region increases by multiplying it with m. I am such an Iensin. It is considered to be a single-focal diffractive lens that functions at the highest level. Lenses with m1 are sometimes referred to as a Multi-Order Diffractive (MOD) lens; they are sometimes used to reduce the thickness of a lens and reduce longitudinal chromatic aberration. As with other diffraction profiles, this profile can be combined with other refraction or diffraction profiles on the same or opposite sides of a lens (not shown in the figure). Figure 6 shows a sawtooth-shaped three-focal diffractive lens profile and its spectrum. In this figure, the diffraction profile of the lens can be seen in the graph above, with the height graph drawn from the optical center according to the radius. The bottom graph contains the spectrum of the lens with intensity I relative to the diopter. Density is shown in arbitrary units. If the height of the single focus diffractive lens in Figure 5 is reduced so that the phase modulation corresponding to the step height is less than 21T, the light is split between 0th order and 1st order. One method to create a trifocal diffractive lens is to combine two such bifocal lenses with different first orders of diffraction. This idea is known in minor variations in the art, the most prominent being B2. A general approach to making such a lens is also known from the teaching of US 5,017,000. The resulting diffractive lens is an asymmetric diffractive lens that functions in the 0, +1 and +2 ranges. There are other, more direct ways to calculate the ideal asymmetric trifocal lens. A frequently desired characteristic of multifocal lenses is to provide a relatively even density distribution for mesopic conditions while providing much stronger relative intensity for distance vision for the larger pupils present in scotopic conditions. In sawtooth-shaped multifocal diffractive lenses, this is often achieved by adaptation, which in this context refers to diffraction gratings in which the height is reduced by increasing the diameter, as taught in the Journal of M. J. Simpson's "History and development of the apodized diffractive intraocular lens." For a lens using a uniformly symmetrical mesh, this simple method cannot be used for this purpose, so an alternative strategy is needed. Such an adaptation process applied directly to a multifocal lens based on a symmetrical mesh causes a very strong 0th order for large pupils. In the original case of the diffractive lens profile seen in Figure 6, which provides distance vision, intermediate vision and near vision, the lens is modeled for a refractive base of 18.5 D used for direct distance vision. The refractive powers of this lens are 1.5 D (intermediate vision) and 3 D (near vision). The majority of diffractive ophthalmic lenses known in the art use "asymmetric" diffraction gratings, as shown with reference to Figures 5 and 6. When symmetrical or asymmetrical qualities are attributed to multifocal ophthalmic lenses, it is taken into account which orders this lens utilizes or makes useful. In symmetrical diffractive lenses, orders are used symmetrically around the Oth order. It should be noted that symmetric diffraction gratings are defined by which orders they use, not by the light distribution in the orders they use. Some symmetrical diffraction gratings can be tuned to have a significant difference in light intensity, for example between +1 and -1 orders. To do this, it is necessary to manipulate the process of tuning the unit cell of the diffraction grating so that it becomes asymmetric, but this is not the case referred to by symmetric or asymmetric diffraction gratings. A diffraction grating set in this way is still considered a symmetric diffraction grating. Although the terms symmetric and asymmetric are not commonly used when referring to diffraction gratings, these terms are in any case very appropriate for the teaching of the disclosed invention and are consistent with the use of the terms in the literature in that a diffraction grating is often defined by which orders are made useful to the user. In a bifocal lens, there will be more than two orders of magnitude of non-zero light intensity, but the difference in intensity (especially at the design wavelength) tends to be significant. A unique case of an optimal trifocal network with uniform density distribution is shown with reference to Figures 7, Figures 8 and Figure 9, which was first introduced by Gori in his 1998 study in lenses with uneven distributions with some minor adjustments in the unit cell lens design. It can even be used. One of these techniques is to shift the diffraction profile horizontally (laterally), a process that changes the light distribution between orders for finite apertures. The most efficient linear phase network for three orders has a diffraction efficiency of 92.56. A trifocal lens with a modeled spectrum is seen. This symmetrical lens functions in the -1, 0 and +1 ranges. Such symmetrical lenses tend to perform at higher diffraction efficiency than asymmetric sawtooth shaped lenses. In addition, relatively smoother mesh shapes are highly desirable because the prevalence of light scattering, glare, and halos is greatly limited. In addition, Osipov's 2015 study proposes the idea that lenses with smooth networks should be "more biocompatible thanks to a reduced effect of residue sedimentation." There are different methods in the art to calculate and adjust symmetrical diffractive lenses. It is a 7-focal lens described in the published study "Computer generated diffractive multi-focal lens" by Golub et al. As a continuation of this, there are additional regulations in the work titled "Fabrication of three-focal diffractive Ienses by two-photon polymerization technique" by Osipov et al., published in the already mentioned Osipov 529. These articles describe trifocal symmetrical lenses made with modifications to a sinusoidal network. However, although these studies provide good approximations, the absolute most suitable diffractive lenses. Another method to adjust and optimize symmetrical or asymmetrical diffractive lenses is to first find the most suitable linear phase network for the desired light distribution, that is, instead of a lens, a light beam is divided into a certain number of times. or finding a linear diffraction that divides into new beams. By treating the x-axis of the linear network as the r2 field of the diffractive lens, any linear phase of this type can be converted into an lens. The best information available in the art on linear phase optimizations can be found in the 2007 work by Romero and Dickey. Using this theory, it is possible to define the considered orders and the relative density distributions of the relevant order and to find the equation for the most appropriate (most efficient) network for these input values. This work also shows that symmetric networks with at least one contiguous order sequence contain optimal networks without discontinuities for relatively equal density distributions. Some symmetric networks with non-contiguous order sequences also have networks without discontinuities. In the Romero and Dickey study, only networks with equal density distributions are shown, but networks with unequal distributions have also been documented using the theory provided. The commonly investigated case is the one in which there is an equal density distribution among the selected orders. The highest diffraction efficiency that can be achieved for equal intensity distribution in a linear network for three focal points is 92.56%. The phase profile for such a linear network, (löiinOC) was originally defined by Gori et al as follows: çbunbc) = tan_ $iin(x) is the phase profile of the linear phase network, x is the axis or distance over which the network extends, [mm]. By this definition, a period is exactly 1 unit long. Using (1), a lens with a phase profile function (Mr) constructed on this network can be defined as: 27T{T2 -S} S is the lateral shift which has a constant value between 0 and 1, and A(r) is often a constant is the amplitude modulation function chosen to be , and T is the period or spacing of the diffraction grating in the rz field [mm2]. The value A(r) of the amplitude modulation function can be constant across the lens surface, for example between 1.05 and 1.15, to take into account the reduction of the diffraction grating height due to lens post-treatment operations, such as polishing. For lens bodies that do not require such post-treatment, the A(r) value may be 1. It should be noted that this formula provides phase modulation. When creating the actual lens, the refractive index of the lens material and also the surrounding medium must be taken into account, which is simple for the professional. The lateral shift S is a way of expressing the phase shift of the periodic lattice, the choice of which adjusts the behavior of the lens. Because the term phase has many meanings in this document, elsewhere in the document the term is referred to simply as lateral shift. An exemplary height profile or amplitude profile expressed in mm2 of a continuous periodic diffraction profile of area is shown, and in Fig. 7b, the same height function is radial, based on the phase profile function gb(r) according to equation (2) along a linear scale. Shown as a function of distance r. As with the single-focal sawtooth lens in Figure 5 or the trifocal sawtooth lens in Figure 6, this lens is strictly periodic in the r2 field, as expected. The amplitude of the height profile H(r) (61) is shown on the vertical axis in um scale. The optical axis passing through the center of the lens body is assumed to be at radial position = 0, the radial distance measured in the outward direction from the optical axis rise is expressed in mm on the horizontal axis. In this embodiment, the design wavelength of the lens is assumed to be 550nm, the refractive index of the lens body is set to 1.4618, and the refractive index of the medium surrounding the lens body is assumed to be 1.336. The amplitude modulation function A(r) 1 is constant at O7, in the field r2 the period is T = 0.733 mm2 and the lateral shift is S = O. The reference number 60 refers to the outer peripheral or baseline curvature of the front surface 34 of the lens body 30 with the diffraction grating or relief 36 containing the height profile H(r) 61 (see Fig. 2a and Fig. 2b). The skilled worker will recognize that a diffraction profile may be located on either or both the front and back surfaces of the lens. The amount of light diffracted by the Iens with height profile H(r) (61) is shown by computer-simulated light intensity distributions in Figure 7c. The reference number (64) refers to the 0 diffraction order, which provides a focal point for intermediate vision, the reference number (62) refers to the -1 diffraction order, which provides a focal point for distance vision, and the reference number (63) refers to a focal point for near vision. Reference is made to the +1 diffraction order that provides the point. In intensity profiles, the intensity I of the diffracted light is displayed on the vertical axis in arbitrary units as a function of the optical power in diopters D, seen on the horizontal axis. In computer-simulated light intensity distributions, it is designed to target a zero-order focal point at (20) diopter D and first-order focal points at 21.5 D and 18.5 D positioned symmetrically with respect to zero order, shown in Figure 2a and Figure 2b. An ophthalmic lens (30) of the type seen is assumed to have a lens body (31) that is convex on both sides. That is, for a zero-order focal point, a focal point is provided for intermediate vision at 20 D, with a -1 diffraction order, a focal point is provided for far vision at 18.5 D, and with a +1 diffraction order, a focal point is provided for near vision at 21.5 D. A focal point for vision is provided. The skilled artisan will appreciate that these optical powers or focal points may differ for actual lenses depending on their target focal point. The samples are calculated using MATLABTM-based simulation software and assuming a pupil size of 6 mm in diameter. As can be seen in Figure 7c, unlike the lens phase profile calculated for the optimal linear triplet by Gori et al., the amount of light incident on the curved lens body is not evenly distributed at the target focal points. This is because the optimal ternary periodic phase profile function was calculated by Gori et al. for a linear or planar phase network, so that the distances between the periods show a linear relationship, and when these calculations are transformed into an Iense, the distances between the periods of the phase profile function contain a square root relationship. Figure 8a shows the height profile 71 as a function of the radial distance r of the diffraction grating in one embodiment of a trifocal ophthalmic intraocular lens. For this arrangement, the design wavelength A, the refractive index of the lens body n, the refractive index of the medium surrounding the lens body nm, the amplitude modulation function A(r) and the period T in the r2 field are the same as the parameters of the arrangement seen in Figures 7a to Figures 7c. Unlike the arrangement seen in Figure 7a to Figure 7c, as seen in Figure 8, the diffractive profile is shifted laterally and modulated by the lateral shift S, which has a constant non-zero value. The reference number 71 refers to the outer periphery or baseline curvature of the front surface 34 of the Iens body 30, which has a diffraction grating or relief 36 extending from the optical axis, H(r) 71 ), which includes the height profile. Figure 8b, Figure 8c and Figure 8d show the Iensin computer-simulated light intensity distributions in Figure 8a for various pupil sizes. In the graphs in Figure 8b, Figure 8c and Figure 8d, the relative intensity of the refracted and diffracted light according to the maximum intensity at one of the focal points is shown on the vertical axis. I is viewed as a function of optical power in diopters D shown on the horizontal axis. Again, these examples are calculated using MATLABTM-based simulation software. In computer-simulated light intensity distributions, a bifacial convex lens body is assumed, designed to target a zeroth-order focal point at (20) diopter D and first-order focal points at 21.5 D and 18.5 D symmetrically positioned with respect to the zeroth order. For a zero-order focal point, a focal point is provided for intermediate vision at 20 D, with a -1 diffraction order, a focal point is provided for distance vision at 18.5 D, and with a +1 diffraction order, a focal point is provided for near vision at 21.5 D. A focal point is provided. Figure 8b shows the light intensity distribution (72) for a 1 mm diameter pupil. As can be seen in Figure 8b, almost all of the light incident on the lens is concentrated at the focal point for intermediate vision at 20 D. That is, when the optical system of a user containing intraocular lenses according to the arrangement in Figure 8a is measured by an automatic refractometer and using a light intensity such that the user's pupil size is approximately 1 mm in diameter, the focal point actually measured by the automatic refractometer is not one of the diffraction focal points but the middle or is the focal point of refraction. In Figure Sc? Light intensity distribution is seen for a mm diameter pupil size. A pupil of this size covers most of the convex surface and diffraction profile of the lens, as seen in Figure 8b with a 1 mm pupil size. The reference number (73) refers to the 0 diffraction order, which provides the focal point for intermediate vision. The reference number (74) refers to the -1 diffraction order, which provides the focal point for distance vision, and the reference number (75) refers to the +1 diffraction order, which provides the focal point for near vision. As can be seen from the intensity profile in Figure 8b, a larger part of the incident light is scattered at the focal point for near vision (75) compared to the amount of light scattered at the focal points for intermediate (73) and far vision (74). Figure 8d shows the light intensity distribution for a pupil size of 6 mm diameter. A pupil of this size usually covers the entire optical system of an ophthalmic lens. Again, the reference number (73) refers to the 0 diffraction order that provides the focal point for intermediate vision, the reference number (74) refers to the -1 diffraction order that provides the focal point for distance vision, and the reference number (75) refers to the near vision Reference is made to the +1 diffraction order, which provides the focal point for The effect of applying a lateral shift to the diffractive profile can be seen by comparing Figure 8d with Figure 7c. In this case, it can be seen that moving the first peak further away from the lens center, as in Figure 8, reduces the relative intensity provided by the 0 diffraction order indicated by the reference number (73), which provides the focal point for the intermediate view. Thus, in designing a multifocal lens, it has been seen that both the target intensity distribution of the underlying diffraction grating can be selected and the actual distribution of the lens can be fine-tuned by lateral shifting of the diffraction pattern. The choice of lateral shift to use can also affect the manufacturability of the lens, as different geometries have very different sensitivities to small distortions. Figure 9 shows another lens using an optimal diffraction unit cell for uniform dispersion over three orders of magnitude ([1 1 1]). Figure 9a shows a unit cell for the resulting order distribution and a bar graph showing this resulting order distribution. The diffraction efficiency of the optimal diffraction grating for equal splitting over three orders is 92.56%. Figure 9b shows the diffraction profile of a lens based on the unit cell above. Figure 9c shows the resulting energy distribution of the lens in Figure 9b. The spectrum is modeled for a 3mm diameter opening and a base crushing force of 20 D is assumed. Equation (1) shows the optimal linear phase network for a trifocal network with uniform density distribution. It is often necessary to design a unique optical network with the required characteristics. The above-mentioned work by Romero et al. describes a methodology to find the optimal linear phase network for a desired set of target focal points and a given density distribution among them. For the case of a three-focus linear network, the unsimplified linear phase network $iian) formula based on the work of Romero et al. is as follows: represent the phases of the corresponding Fourier coefficients of the function, lakl/yk=N, where N is a positive constant, and |ak| represents the amplitude of the Fourier coefficient ak of the diffraction grating for k = 1, 2, 3, x is the axis along which the grating lies. By this definition, a period is exactly 1 unit long. It can be used for the trifocal part of a lens by replacing ag x in equation (3) with the square of the lens radius r. More specifically, x must be replaced by (r2 - S(r))/Tile to arrive at the equivalent of equation (2). It should be noted that the entire setup for finding the optimal network is not included in the present document, as this is available in the cited literature. The formula in Equation (3) can be optionally extended to describe other structures. Lenses with four, five and seven focal points are particularly interesting. Now, from the linear network in equation (3), a lens equation equivalent to equation (2) above can be constructed. Using the phase profile $iin(x) defined in Equation (3), it is obtained: cm) = Am * cpu-n (ÜS) (4› (Mr) is the continuous periodic phase profile function of the lens diffraction grating, r is the optical phase of the lens body is the radial distance or radius outward from the axis, [mm], A(r) is the amplitude modulation function which is often chosen to have a constant value, S is the lateral offset and has a constant value varying between 0 and 1 * T, and T is rz It is the period or spacing of the diffraction grating in the field [mm2].It should be noted that due to the way the theory in the work of Romero and others is applied here, the focal points for distance and near vision correspond to positive and negative diffraction orders, respectively. This is the opposite of the way used elsewhere in the description of the present application. From this perspective, such reversals of orders and focal points are trivial. Using the work of Romero et al. and the mathematics in equation (3) to find the optimal trifocal network with equal division over the orders (-1, 0, +1), the following equation is obtained: This definition is identical to equation (1) above except for a shift of 90 degrees (0.25 * T). When making a lens, shift must be taken into account by changing S appropriately to account for this shift. Optionally, any of the formulas in equation (1) or equation (5) can be chosen. If instead an equal intensity distribution of the diffraction grating is to be achieved, for example a (near, middle, far) division of [1,2, 1, 1], one way to express the optimal diffraction grating that meets these requirements is to follow the teachings of Romero et al. is to apply as per equation (3), which is the set of diffraction efficiency and constants set as follows: An important aspect of the general formulation of trifocal linear networks optimized in equation (3) is the splitting with equal intensity [1 1 1] 92.56% diffraction Although this is the most suitable solution with diffraction efficiency, there are solutions with significantly higher diffraction efficiencies in many other intensity distributions. Figure 10 is similar to Figure 9, but is based on a diffraction unit cell optimized for intensity distribution [1,2 1 1]. The diffraction efficiency of this dispersion is 91.26, which is slightly lower than that for even dispersion. Here, this process is done in such a way that the levels in the lens [Near, Middle, Far] are related to the intensities. The order chosen is such that the strongest power (corresponding to the focal point closest to the user) is first and the weakest power is last. The diffractive lens profile in Figure 10c is identical to the lens profile in Figure 9c except that the refractive indices and lateral shift are identical for the selected cell unit. The spectrum is modeled for a 3mm diameter opening and a base crushing force of 20 D is assumed. In Figure 10c, it can be seen that the near density has been increased compared to Figure 9c. It is based on the diffraction unit cell. The diffraction efficiency of this distribution is 93.88, which is slightly higher than that for the uniform distribution in Figure 9 and higher than the cell unit used in Figure 10. The diffraction efficiency of this unit cell is higher than that for equal-intensity splitting over three orders, which is often cited in the literature as optimal splitting. In the specific case of trifocal gratings, very high diffraction efficiencies are achieved for high 0th order intensities, but this is not a general rule as discussed further below. In detail, this is not the case for diffraction gratings optimized for five focal points. The diffractive lens profile in Figure 11c is identical to the lens profile in Figure 9c and Figure 10c except that the refractive indices and lateral shift are identical for the selected cell unit. The spectrum is modeled for a 3mm diameter opening and a base crushing force of 20 D is assumed. In Figure 11c, it can be seen that the relative far density is reduced compared to Figure 9c and Figure 10c. The spectrum is modeled for a 3mm diameter opening and a base crushing force of 20 D is assumed. Figure 12 shows the relationship between the choice of lateral shift and the choice of diffraction gratings to suit the behavior of a multifocal incident lens. In the literature on optical beam splitting, which is partially taught in the present invention, the term "optimal" is typically used for the most efficient network for a given number of orders with equal intensity distribution over the orders. However, this does not have to be the case for lenses: in certain lens structures, a higher overall diffraction efficiency can very well be exploited. As can be understood from the illustrations in Figure 9, Figure 10 and Figure 11, the highest possible diffraction efficiency depends on the required intensity distribution. The density distribution for a given phase network is determined by the lateral shift of the network (within some limits) 7). Provides a full period shift prime lens. Figure 12a, Figure 12b and Figure 12c show how the simulated densities for three different networks, Far, Near and Middle, change at 3mm aperture for different lateral shift when making the lens. Lenses have a structure that provides distance vision, (0th order) intermediate vision and near vision as part of each lateral shift period. These three tables show the intensity for each focal point as a function of the lateral shift 8 in equation (4) for each diffraction unit cell. The behavior in Figures 9a to 90 is the expected behavior, where the higher 0th order chosen provides a higher median view. This is also valid for other levels, provided that the necessary changes are made. However, it should be noted that the stronger order in the underlying linear phase network is not necessarily stronger for every 8 possible. On the contrary, it is clear from these tables that it is important to choose the correct value for 8 to achieve the desired light distribution. Figure 12d shows the total density in arbitrary units for each network. A higher total indicates an efficient diffractive lens. The graph in Figure 12d compares the sums of the three intensities for each selected diffraction grating. The sum of the peaks is a good indicator of the effective diffraction efficiency. It can be seen that the change in this parameter corresponds closely to the change in diffraction efficiency between the networks. It should be noted that a given lateral shift with higher diffraction efficiency will generally provide a more efficient lens, but a poorly chosen lateral shift with an efficient mesh will perform worse than a less efficient mesh with a more favorable lateral shift. Most of the time, manufacturability and behavior for different spans constrain the choice of lateral offset (i.e. choice of parameter value 8). Using the calculations included in the modeling in Figures 12a to Figure 12d, an example of such a region is 0.45 < 8 * T< 0.7. In addition, it is often convenient to choose a grating with high diffraction efficiency. In detail, lenses with high refractive efficiency certainly provide more usable light to the eye, but such lenses also reduce the amount of light going into unwanted diffraction ranges and undesirable effects such as halo and flare. However, trifocal gratings with very high diffraction efficiency used over the entire lens optics cause undesirable intensity distributions. For trifocal symmetrical lenses, a very high diffraction efficiency tends to lead to a very strong zero order. The diffraction unit cell (which is the focal point) is seen. This linear phase network provides a very high diffraction efficiency of 98.98%. This value is significantly higher than the optimized diffraction grating for the five-focal grating with an equal intensity splitting [1 1 1 1 1], the intensity dispersion of this pentafocal grating is 92.13%. Figure 13b shows the diffractive lens based on the diffraction unit cell in Figure 13a. The spacing of the diffraction grating of this novel arrangement is such that it provides 2.13 D between the strongest and weakest focus, where the Iens design wavelength of 550 nm is assumed, the refractive index of the lens body is set to 1.492, and the refractive index of the medium surrounding the lens body is assumed to be 1.336 . In this way, this unique example provides the user with five focal points, distributed mostly in and between distance and intermediate vision. By rearranging the spacing of the diffraction grating, a five-focal lens can be achieved, providing near vision in addition to distance and intermediate vision, of course. Figure 13c is the modeled spectrum corresponding to the diffractive Iens profile in Figure 13b, shown as relative intensities, with the highest peak set to 1. The spectrum is modeled for a 6mm aperture, assuming a base crushing force of 20 D. For penfocal symmetrical lenses, very high diffraction efficiency tends to provide very strong first orders, which are relatively weaker. Figure 14 shows one way to make a lens according to the invention by combining a trifocal field with a different refractive base from the central part of the lens. In Figure 14a it is made entirely of a three-focus linear phase network. The aperture has a structure that provides a first-order diffraction power of 1.675 D. 8 is set to 0.48 * T as defined by equation (3) and equation (4). Figure 14b shows the profile of a lens according to the present invention, excluding the refractive base power of 20 D. The lens contains only a refractive central part placed within the diffraction grating of Figure 14a, in which case the diameter of the single-focal central region is 1.03 mm. The power of the single focal central region is -1.675 D, so that the focal point it provides coincides with the diffractive far power of the diffraction grating. The base refractive power of the lens (not shown) coincides with the intermediate power. It should be understood that this is only an example and that any type of diffraction surface can be used, such as a portion of a single-focus diffraction grating, a spherical surface, or any form of non-spherical surface. For most applications, a properly designed non-spherical diffraction surface is suitable. The modeled density distributions in Figure 14c show how this unique lens works. The density distribution is relatively even at different apertures. The lens uses a highly efficient diffraction unit cell with no significant peaks except the desired three peaks. A lens constructed accordingly can function as a so-called enhanced depth of focus (EDOF) lens because it has strong distance vision but still distributes enough light near and far to allow the wearer to participate in most activities without other ophthalmological tools. The combination of a multifocal grating with a single-focal central region allows using diffraction gratings with very high grating efficiencies, since the strong farsight of the central region can be used to offset the limitations of such gratings. This type of lens geometry, particularly multifocal lenses that contain a broader array of intensity distribution profiles with a wider difference in intensity distribution between different apertures. Additionally, this lens structure provides a way for an ophthalmologist to perform in-vivo measurements from the single-focal portion of the lens, which It is also sometimes convenient. In the specific case of the lens of Fig. 14, this single focal part interferes with distance vision, which is often measured by another lens according to the present invention, shown in Fig. 15. In Figure 15a, the intensity distribution [0.87 linear phase mesh provides a diffraction efficiency of 98.54%; This is significantly higher than the diffraction efficiency of equal intensity splitting grating. Figure 15b shows a lens profile with a refractive base of 20 D. The unit in Fig. 15a is a simple fivefocal grating (not shown) with an 8 as defined by equation (3) and equation (4) and a first-order optical power of 0.84 D, set to 0.8 * T ) is used to create. The lens contains only a refractive central part placed within the diffraction grating of Figure 14a, in which case the diameter of the single-focal central region is 1.14 mm. The power of the single focal central region is -1.675 D, so that the focal point it provides coincides with the diffractive far power of the diffraction grating. The base refractive power of the lens (not shown) coincides with the intermediate power. It should be understood that this is only an example and that any type of diffraction surface can be used, such as a portion of a single-focus diffraction grating, a spherical surface, or any non-spherical surface form. Modeling for different aperture sizes in Figure 15c shows that this novel lens provides strong distance vision for all apertures and well-developed multifocality for larger apertures. It should be noted that a penfocal lens has a more dispersed spectrum than most conventional multifocal lenses. The two second-order foci may be referred to as near vision and distance vision, and the 0th order may be referred to as intermediate vision. There are also two additional focuses here. Together, they can provide the user with a relatively uninterrupted view. Both the examples in Figure 14b and Figure 15b illustrate lenses according to the invention, which are taken here. However, this is by no means the only structure of interest. In recent years, enhanced depth of focus (EDOF) has been increasingly discussed. Figure 15b describes a lens with two additional focal points between the far, intermediate and near focal points to provide the user with continuous vision10. In another structure of interest, the focal points of the symmetrical diffractive lens in accordance with the patent are located for one or more diffraction orders, which form the focal point(s) in distance vision, intermediate vision and optical power(s) between these distance and intermediate vision. Commercially available EDOF lenses often only target far and intermediate powers but do not offer continuous vision across these distances. In this paper, linear phase networks are shown to be a possible starting point for creating multifocal lenses. Current theory and understanding of such networks can also be used to analyze lenses if the underlying linear phase network can be extracted from the lens. The simplified flow diagram 160 in Figure 16 shows the steps of a method for measuring the profile of a multifocal ophthalmic lens and determining the diffraction efficiency of the underlying diffraction grating. The direction of flow is from the top to the bottom of the drawing. In a first step, a region of the lens is selected and measured in block 161, preferably along a line perpendicular to the optical axis. In a second step, in block 162, the curvature of the base crushing power of the selected region is subtracted from the measured profile. Sometimes part of the refractive base is actually a single-focal phase-coherent Fresnel lens or MOD lens, in which case this single-focus diffraction pattern must be subtracted from the measured profile. In a third step, at block 163, the resulting lens profile is plotted against the square root of the distance to the optical center. In a fourth step, the underlying linear phase is obtained by transforming the height profile from the previous step using the design wavelength, the refractive index of the ophthalmic lens, and the refractive index of the specified medium in the eye. Finally, in a fifth step, in block 164, the diffraction efficiency and linear grating for the usable orders are calculated. Once the phase profile of the underlying linear phase network is known, it is possible to calculate the diffraction efficiency. If it is a phased network (Mx), the transmission function can be written as follows: T(X) : eiçbÜC) (7) The efficiency of each diffraction order or a combination of diffraction orders can be found by examining the Fourier coefficients of the transmission function. If the length of the diffraction unit cell is 1, the Fourier coefficients can be written as follows: TR = fileiçb(x)-2ikrr (8) For phase-only networks, the situation is as follows: lêîîînlrklz = 1 (9› These Fourier coefficients specified by k correspond to the relevant diffraction orders, their diffraction Its efficiency can be written as ri, 17 = lrkl2. For example, for a trifocal lens operating in the order of k = -1.0, 1, the total diffraction efficiency can be written as: Extending the numerical applications of these analytical results, such as calculating the diffraction efficiency of a measured diffraction grating. It is easy. The professional practicing the claimed invention can see and realize different variations from the examples and embodiments described by examining the drawings, description and attached claims. The word "comprises" in the claims does not exclude other elements or steps, and the indefinite adjective "an" does not exclude the plurality in different dependent claims. The specific measures cited do not indicate that a combination of these measures cannot be used favorably. Any reference notation in the claims should not be construed as limiting the scope of the claims. Equal or equivalent elements or processes are referred to with the same reference signs. According to one embodiment of the present invention, a multifocal ophthalmic lens is proposed comprising at least three focal points, the lens having a light-transparent lens body, the lens body having at least a first part and a second refractive base power coinciding with the central area thereof. It contains a second part with a crushing power. In another embodiment of the present invention, the multifocal ophthalmic lens further includes a multifocal symmetrical network combined with the second part, wherein the structure of the combination with the second part is such that a diffraction order of this multifocal symmetrical network will be added to the base refractive power of the central area coinciding with the first part for the design wavelength. and the diffraction grating has a higher diffraction efficiency than the diffraction efficiency of the corresponding diffraction grating with equal light distribution. In another embodiment of the present invention, the first refractive base of the first part of the multifocal ophthalmic lens and the second refractive base of the second part are unequal. In another embodiment of the present invention, at least a first portion, at least a second portion, or both of these portions include a sawtooth shaped diffraction grating. In another embodiment of the present invention, the sawtooth shaped diffraction grating is single focal. In another embodiment of the present invention, the multifocal lens is a trifocal lens, with a correspondingly multifocal symmetrical network providing three focal points. In another embodiment of the present invention, the multifocal lens is a five-focal lens and the corresponding multifocal symmetrical network provides five focal points. In another embodiment of the present invention, the multifocal symmetric network provides a number of focal points selected from a group including, but not limited to, four, five, nine focal points. In another embodiment of the present invention, the multifocal symmetric network of at least a first part and the multifocal symmetric network of at least a second part provide different numbers of focal points. In another embodiment of the present invention, many focal points provided by these multifocal symmetrical networks are in a structure that provides distance, intermediate and near vision. In another embodiment of the present invention, the placement of many focal points provided by multifocal symmetrical networks is such that the power difference between the focal point with the highest optical power and the focal point with the lowest power is at most 2 Diopters. In another embodiment of the present invention, the ophthalmic lens further includes a transition zone between at least a first part and at least a second part, whereby a refractive base power or a range of refractive powers is achieved between the refractive powers of at least a first and at least a second part. Crushing base power is provided. According to an embodiment of the present invention, a method is proposed to measure the profile of a multifocal ophthalmic lens, preferably outward from the optical center of the ophthalmic lens. According to another embodiment of the present invention, this method includes the step of selecting a region of the measured profile containing a diffraction pattern. According to another embodiment of the present invention, the method includes the step of removing the curvature of the base crushing power of the selected region. According to another embodiment of the present invention, the method includes the step of removing any diffraction periodic grating(s) having maximum phase modulation greater than the design wavelength of the ophthalmic lens. According to another embodiment of the present invention, the method includes the step of plotting the resulting lens profile against the square root of the distance to the optical center. According to another embodiment of the present invention, the method includes the step of obtaining a linear phase mesh by converting the height profile in the previous step into a phase profile using the refractive index of the ophthalmic lens and the refractive index of the medium determined in the eye. According to another embodiment of the present invention, this method includes the step of calculating the diffraction efficiency for usable orders and the design wavelength of the linear grating.TR TR TR

Claims (1)

1. CLAIMS A multifocal ophthalmic lens comprising at least three focal points, the lens having a light-permeable lens body, the lens body having at least a first part having a first refractive base power and a second refractive power coinciding with the central area thereof. It contains a second part, the first part and the second part are located concentrically, its features are as follows: the first part is a single focal area that provides distance vision, the multifocal ophthalmic lens also contains a multifocal symmetrical network combined with the second part, this multifocal symmetrical network , is a periodic, regular sinusoidal network in the field r2, whose orders are symmetrically located around the Oth order, where the structure of the combination with the second part is such that a diffraction order of the multifocal symmetric network is added to the base refractive power of the central field coinciding with the first part for the design wavelength, The structure of the uniform sinusoidal diffraction grating combined with the second part is such that the diffraction efficiency of the linear phase grating underlying it is higher than the diffraction efficiency of the corresponding optimal linear diffraction grating with the same usable orders, the diffraction efficiency of the uniform sinusoidal diffraction grating being the square root of the optical distance to the center of the lens. It can be obtained by drawing the network profile graph according to; And. The first breaker base of the first part and the second breaker base of the second part have an unequal structure. The multifocal ophthalmic lens according to claim 1, characterized as follows: the multifocal lens is a three-focal lens and a correspondingly multifocal symmetrical network provides three focal points. Multifocal ophthalmic lens according to claim 1 or 2, characterized in that: the multifocal lens is a five-focal lens and a correspondingly multifocal symmetrical network provides five focal points. It is a multifocal ophthalmic lens according to any of the previous claims, characterized in that the multifocal symmetrical network provides a number of focal points selected from a group including, but not limited to, four, five, nine focal points. It is a multifocal ophthalmic lens according to any of the previous claims, characterized in that the multifocal symmetric network of at least one first part and the multifocal symmetric network of at least one second part provide different numbers of focal points. It is a multifocal ophthalmic lens conforming to any of the previous claims, and its feature is that many focal points provided by multifocal symmetrical networks are in a structure that provides distance vision, intermediate vision and near vision. 7) It is a multifocal ophthalmic lens conforming to any of the previous claims, and its feature is that many focal points provided by multifocal symmetrical networks are located in such a way that the power difference between the focal point with the highest optical power and the focal point with the lowest power is at most 2 Diopters. 8) Multifocal ophthalmic lens according to any of the previous claims, characterized in that: the ophthalmic lens also includes a transition zone between at least one first part and at least one second part, thanks to this region, at least one first and at least one second part is refractive. A crushing base power or a series of crushing base powers are provided between the forces. 9) It is a multifocal ophthalmic lens according to any of the previous claims, characterized in that the multifocal diffraction grating includes at least one separate order located between distance and middle vision so that improved depth of focus is obtained. 10) It is a multifocal ophthalmic lens according to any of the previous claims, and its feature is that the multifocal diffraction network has at least four separate structures, two of which are located between intermediate and far vision and the other two are located between intermediate and near vision, providing improved continuity between these types of vision. It contains levels. 11) Method for measuring the profile of a multifocal ophthalmic lens according to any of the previous claims, preferably from the optical center of the ophthalmic lens outward, characterized in that it includes the following steps: l) the region of the measured profile with a diffraction pattern is selected, ll) the curvature of the base refractive power of the selected region. is eliminated, lll) plot of the resulting lens profile versus the square root of the distance to the optical center lV) linear phase mesh is obtained by converting the height profile from the previous step to a phase profile using the design wavelength, the refractive index of the ophthalmic lens, and the refractive index of the specified medium in the eye, V) linear The diffraction efficiency is calculated for the available ranges of the network. TR TR TR