CN113995552A

CN113995552A - Method for manufacturing artificial lens for precise surface shape control and artificial lens

Info

Publication number: CN113995552A
Application number: CN202010732335.8A
Authority: CN
Inventors: 赵昭
Original assignee: Henan Saimeishi Biotechnology Co ltd
Current assignee: Henan Saimeishi Biotechnology Co ltd
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2022-02-01

Abstract

The application discloses an artificial lens manufacturing method for accurate surface shape control, which comprises the steps of obtaining an optical surface shape target model, carrying out optical processing based on the optical surface shape target model, and processing to obtain an artificial lens; carrying out actual measurement to obtain actual measurement surface profile data; performing mathematical modeling based on actually measured surface profile data to generate an optical surface actual model; judging whether the optical surface type actual model meets the surface type control requirement and preset performance indexes; if not, one or more parameters in the optical surface type target model are optimized until the requirements are met. This application can control the compensation to machining error, has overcome intraocular lens self deformation characteristic and has leaded to the face type error to increase in the actual manufacturing process, realizes the accurate control to the optical face type, makes the optical quality of intraocular lens product obtain effectively improving in full optical aperture department. In addition, the present application also provides an intraocular lens.

Description

Method for manufacturing artificial lens for precise surface shape control and artificial lens

Technical Field

The present invention relates to a method for manufacturing an intraocular lens, and more particularly, to a method for manufacturing an intraocular lens for precise surface shape control and an intraocular lens manufactured using the same.

Background

The technical description provided in this section is for the purpose of generally presenting the context of the disclosure and may or may not constitute prior art.

Intraocular lens refers to a special lens made of synthetic materials including silicone, polymethylmethacrylate, hydrogel, and the like. The artificial lens has the shape and the function similar to the natural lens of human eyes, and has the characteristics of light weight, high optical performance, no antigenicity, inflammation, carcinogenicity, biodegradability and the like.

The artificial lens is widely applied to the field of cataract medical treatment, the turbid crystalline lens is removed after cataract surgery, the artificial lens is implanted into an eye to replace the original crystalline lens, and external objects are focused and imaged on a retina, so that the aim of seeing surrounding scenes clearly is fulfilled.

The process from seeing the cataract patient to seeing clearly and then pursuing high-quality visual effect promotes a series of development of the artificial lens, and different types of artificial lenses are generated. From the viewpoint of the optical surface type of the intraocular lens, the intraocular lens can be classified into a spherical intraocular lens and an aspherical intraocular lens. The aspheric intraocular lens has the advantages that clearer imaging quality can be provided for patients, particularly, when light is insufficient at night, pupils are enlarged, more light enters eyes, and spherical aberration control of the edge of the aspheric surface is particularly important. The control of spherical aberration and other aberrations is closely related to individualization differences on the one hand and the optical quality of the intraocular lens itself on the other hand. Therefore, performance indicators for intraocular lenses are a focus of attention for those skilled in the art.

In the manufacturing process of the intraocular lens, a difference between a theoretical design value of the intraocular lens and an actually manufactured product may be caused due to various reasons such as a self-deformation characteristic of the intraocular lens and an error in the actual manufacturing process. Therefore, how to realize the accurate control of the surface shape of the artificial lens so as to improve the accuracy and stability of the design output conversion is a difficulty in manufacturing the artificial lens. Furthermore, for intraocular lenses, particularly aspherical intraocular lenses, the deviation of the theoretical design values from the actual values of the surface profile is generally more pronounced at large apertures. Therefore, how to realize the accurate control of the surface shape of the intraocular lens under the condition of large aperture so as to control the accuracy of performance indexes such as spherical aberration under the condition of large aperture is an important technical problem faced by the technical personnel in the field.

Disclosure of Invention

To solve the above problems, the present application proposes a method for precisely controlling the profile of an intraocular lens. The method can overcome adverse factors such as processing errors of the artificial lens, enables the actual value of the artificial lens to approach the theoretical design value, and achieves the purpose of controlling the accurate surface type. Moreover, the surface shape of the artificial lens can be effectively controlled and optimized in a large aperture range.

According to an aspect of the present application, there is provided a method of manufacturing an intraocular lens, comprising the steps of:

s11: obtaining an optical surface type target model, and carrying out optical processing on the basis of the optical surface type target model to obtain an artificial lens;

s12: actually measuring the optical surface type in the artificial lens to obtain actually measured surface type contour data;

s13: performing mathematical modeling based on the actually measured surface profile data, and performing inversion to generate an optical surface actual model;

s14: judging whether the optical surface type actual model meets the surface type control requirement or not; if the optical surface type actual model does not meet the requirement, optimizing one or more parameters in the optical surface type target model, determining the optimized optical surface type target model, and returning to execute the step S11 until the optical surface type actual model meets the surface type control requirement;

s15: judging whether the artificial lens finally meeting the surface type control requirement reaches a preset performance index; if the preset performance index is not met, model compensation adjustment optimization is required, and the execution returns to S11 until the artificial lens meets the preset performance index.

Optionally, S13 mathematically modeling based on the actual measured profile data, and the inverse generating of the optical profile actual model includes:

determining a surface type curve according to the optical surface type target model;

and taking the actually measured surface profile data as fitting data of the surface curve, and performing data inversion to generate an optical surface actual curve.

Optionally, taking the actually measured surface profile data as fitting data of the surface curve, and performing data inversion to generate an optical surface actual curve includes:

and taking the actually measured surface profile data as fitting data of the surface curve, and performing data inversion by adopting a least square method to generate a surface curve model.

Optionally, determining a profile curve according to the optical profile target model comprises:

if the artificial lens is a spherical or aspherical artificial lens, the optical surface type is correspondingly spherical or aspherical, and the surface type curve is determined as follows:

wherein z is the optical surface rise value, k is the conic coefficient, c is the curvature, is the reciprocal of the radius of curvature, r is the radial distance of a point on the lens from the y-axis, a₂、a₄、a₆… is an aspheric coefficient, when k and the aspheric coefficient are both 0, the surface type is characterized as spherical; otherwise, the aspheric surface is represented;

if the artificial lens is astigmatic artificial lens, the optical surface type is planned to be a toric surface, and the surface type curve is determined as follows:

wherein Z is the rise of the toric surface, c_x，c_yThe curvatures of two toric meridians are respectively inverse of the curvature radius, k_x、k_yIs composed of twoThe conic coefficient of the principal meridian of the curved surface, r is the axial distance from the center of the lens, and theta is the meridian angle;

if the artificial lens is bifocal, trifocal or extended focal depth type, the optical surface type is planned to be a diffraction surface type with different annuluses and different step height combinations or a refraction/diffraction mixed surface type.

Optionally, the optical surface type of the intraocular lens includes a first optical surface type and a second optical surface type which are distributed front and back, one or more parameters in the optical surface type object model are optimized, and determining the optimized optical surface type object model includes:

and performing iterative optimization compensation on the established mathematical model according to the difference between the actual parameter feedback and a preset performance index, wherein the iterative optimization compensation comprises the optimization of one or more parameters in the first optical surface type and/or the second optical surface type.

Optionally, before S11, the method further includes:

and determining an optical surface type target model according to the technical indexes of the artificial lens.

Optionally, the performing optical processing according to the optical surface type object model and based on the optical surface type object model includes:

and determining processing parameters according to the optical surface type target model, and performing optical processing by adopting a single-point diamond numerical control turning machine.

Optionally, S12 performing actual measurement on the optical profile of the intraocular lens, and acquiring actual measurement profile data includes:

and actually measuring the optical surface of the artificial lens by adopting a contact type or a non-contact type to acquire actually measured surface profile data.

Optionally, the determining whether the optical surface type actual model meets the surface type control requirement and the preset performance index includes:

judging whether the spherical aberration of the optical surface type actual model is smaller than or equal to a preset spherical aberration threshold value, and if the spherical aberration of the optical surface type actual model is smaller than or equal to the preset spherical aberration threshold value, judging that the optical surface type actual model meets surface type control requirements and preset performance indexes; and if the spherical aberration of the optical surface type actual model is larger than the preset spherical aberration threshold value, judging that the optical surface type actual model does not meet the surface type control requirement and the preset performance index.

Optionally, the preset performance index includes any one or any combination of the following: spherical aberration, astigmatism, chromatic aberration.

In another aspect of the present application, there is also provided an intraocular lens manufactured using the aforementioned manufacturing method.

According to the manufacturing method of the artificial lens, the mathematical model is established through the artificial lens surface shape obtained through optical numerical control machining, inversion is carried out on the artificial lens surface shape by using the least square method according to the deviation between actual machining and theoretical surface shape, and the final compensation model is fed back to a lathe for machining until the deviation of the surface shape after final compensation machining meets the controllable requirement. Lathed iols also have a cumbersome manufacturing process that affects their optical properties due to temperature changes, hydration, injection molding, etc., for which the present application is directed to how to combine optical property changes in the manufacturing process with optical surface type iterations. According to the characteristics of the manufacturing process, the performance of the artificial lens can meet the performance index requirement through continuous iteration of the surface type. The compensation method overcomes the defects that the deformation characteristics (such as shrinkage or expansion and the like) of the artificial lens and the increase of surface errors are caused in the actual manufacturing process, realizes the accurate control on the optical surface, further improves the accuracy and stability of design output conversion, effectively improves the optical quality of the artificial lens product at the full optical aperture, and is favorable for manufacturing the high-precision and accurate aspheric surface/free-form surface artificial lens. The surface type control of the optical processing is that the surface type requirement is carried out on the self-production source of the artificial lens, which is beneficial to effectively evaluating the error in the subsequent artificial lens manufacturing process. In addition, the application also provides an artificial lens with the technical effect.

This summary is not intended to identify key or critical features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall be understood from the drawings and description that follow.

Drawings

Hereinafter, the present application will be further explained with reference to the drawings based on embodiments.

FIG. 1 schematically illustrates a flow chart of one embodiment of a method of manufacturing an intraocular lens provided herein;

FIG. 2 schematically illustrates a flow chart of another embodiment of a method of manufacturing an intraocular lens provided herein;

FIG. 3 schematically illustrates a schematic view of an embodiment of a method of manufacturing an intraocular lens provided herein;

FIG. 4 is a diagram showing the deviation between the actual input surface shape and the tested surface shape in a certain direction;

FIGS. 5-6 show schematic diagrams comparing interference patterns with deviations between simulated theoretical design values and actual process measurement values, respectively;

FIG. 7 shows a schematic of a process variation and fit data curve;

FIG. 8 shows a schematic diagram of fit residuals;

FIG. 9 shows a schematic diagram of the interference fringes after compensation;

FIG. 10 is a schematic diagram showing a deviation curve of a theoretical aspheric design from an actual surface profile;

FIGS. 11-12 show schematic diagrams comparing interference patterns with deviations of simulated theoretical design values and actual process measurement values, respectively;

FIG. 13 is a graph showing the difference between the actual deviation point of the process and the curve generated by fitting the data;

FIG. 14 shows a schematic of a process variation and fit data curve;

FIG. 15 shows a deviation diagram of a fitted curve;

FIG. 16 shows a schematic diagram of the interference fringes after model modification;

FIG. 17 shows a schematic representation of a front surface profile variation;

FIG. 18 shows a schematic representation of a back surface profile variation;

FIGS. 19-20 show schematic diagrams comparing theoretical design to actual processing, respectively;

FIG. 21 shows a schematic diagram of the results of model optimization.

Detailed Description

The method of the present application will be described in detail below with reference to the accompanying drawings and specific embodiments. It is to be understood that the embodiments shown in the drawings and described below are merely illustrative and not restrictive of the application.

FIG. 1 illustrates a flow chart of one embodiment of a method of manufacturing an intraocular lens provided herein. In this embodiment, the method specifically includes:

s11: acquiring an optical surface type target model, and carrying out optical processing based on the optical surface type target model to obtain an artificial lens;

the optical surface type target model can be designed based on technical indexes or preset performance indexes, and can also be an updated optical surface type target model after subsequent iterative optimization. After the optical surface type object model is determined, optical processing is performed based on the optical surface type object model, so that an actual artificial lens is obtained. As a specific embodiment, the artificial lens can be automatically processed by adopting a numerical control lathe optical processing mode, and the artificial lens is not limited to the specific mode.

S12: actually measuring the optical surface type in the artificial lens to obtain the profile data of the actually measured surface type;

after the actual intraocular lens is processed, the actual measurement can be carried out on the surface profile of the intraocular lens so as to restore the processed surface profile, and the actual measurement surface profile data can be obtained, and the accuracy of processing can be evaluated through the data. The measurement process can adopt contact measurement or non-contact measurement, which does not influence the realization of the application.

for intraocular lenses with different optical parameters, this can be achieved by different optical surface types. For example: spherical and aspherical surfaces; the aspheric surface can be a toric surface, a diffractive surface, a mixture of refractive and diffractive surfaces or a superposition combination of multiple surface types. Different optical surface types may correspond to different optical surface type object models.

Specifically, in the present embodiment, the optical surface model may be specifically characterized by a surface curve. Step S13 may specifically be: determining a surface type curve according to the optical surface type target model; and taking the actually measured surface profile data as fitting data of the surface curve, and performing data inversion to generate an optical surface actual curve.

Taking the optical surface type as an aspheric surface, a spherical surface or a compound curved surface as an example, specifically:

if the optical surface type is an aspheric surface or a spherical surface, determining the surface type curve as follows:

wherein z is_asphIs the optical surface rise value, k is the conic coefficient, c is the curvature, is the inverse of the radius of curvature, r is the radial distance of a point on the lens from the y-axis, a₂、a₄、a₆… are aspheric coefficients; when k and the aspheric surface coefficient are both 0, the surface type is characterized as a spherical surface; otherwise, it represents an aspheric surface.

If the artificial lens is astigmatic artificial lens, when the optical surface type is a toric surface, determining the surface type curve as:

wherein Z is the rise of the toric surface, c_x，c_yThe curvatures of two toric meridians are respectively inverse of the curvature radius, k_x、k_yIs the conic coefficient of the principal meridians of the two toric surfaces, r is the axial distance from the center of the lens, and θ is the meridian angle.

In this embodiment, the actually measured surface profile data may be used as fitting data of the surface curve, and a least square method is used for performing data inversion to generate the optical surface actual curve. And is of course not limited to this particular manner.

S14: judging whether the optical surface type actual model meets the surface type control requirement or not; if the optical surface type actual model does not meet the surface type control requirement, optimizing one or more parameters in the optical surface type target model, determining the optimized optical surface type target model, and returning to execute the step S11 until the optical surface type actual model meets the surface type control requirement;

In the actual manufacturing process of the artificial lens, there is a difference between the theoretical design value and the actual manufacturing. The intraocular lens is subjected to other manufacturing processes besides machining, which also affect the optical properties of the intraocular lens, and the reason for analyzing the intraocular lens is also due to the change of the surface type, so that in addition to the machining, other processes such as hydration, injection molding, temperature and the like, which may greatly affect the surface type, need to be comprehensively considered. In order to approach the theoretical design infinitely, the established optical surface type actual model can be continuously corrected and optimized to reach the theoretical design value after actual processing. Meanwhile, the process is continuously optimized, so that the accurate control of the surface type of the artificial lens is achieved, and the optimization of the optical performance is realized.

It is understood that the optical profiles of the lenses referred to herein may include a first optical profile and a second optical profile in an anterior-posterior arrangement. The first optical surface type and the second optical surface type can be the same surface type or different surface types. For example, the anterior surface is spherical and the posterior surface is aspherical; or the front surface is an aspheric surface, the back surface is a spherical surface, or both surfaces are aspheric surfaces; an aspherical surface-based ellipsoid, a diffraction surface, and a free-form surface may be used. In this case, the optimizing one or more parameters in the optical surface type object model, and determining the optimized optical surface type object model may specifically include: and optimizing one or more parameters in the first optical surface type and/or the second optical surface type, and determining an optimized optical surface type target model. Aiming at the condition of two optical surface types, the operation of performing measurement optimization on the two surface types can be respectively performed, or only one of the two surface types can be subjected to measurement optimization, so that the integral surface type control of the artificial lens meets the requirement finally. Without departing from the scope of the present application.

For the manufacturing of the artificial lens, the surface control is a necessary condition for achieving accurate optics, the optical performance index of the artificial lens is mainly realized through the surface control, but the optical surface after optical processing changes due to different lens materials and processing technologies, so that the processing surface is controllable, the performance of the artificial lens also needs to be monitored and iteratively corrected, and a method for further iterative optimization when the performance of the artificial lens does not meet the requirements after processing error compensation and adjustment is proposed.

Figure 2 illustrates a flow chart of another embodiment of a method of manufacturing an intraocular lens provided herein. In this embodiment, the method specifically includes:

s20: determining an optical surface type target model according to the technical indexes of the artificial lens;

s21: determining processing parameters according to the optical surface type target model, and performing optical processing by adopting a single-point diamond numerical control turning machine to obtain the artificial lens;

the numerical control lathe optical processing utilizes digital programming to realize automatic operation of a machine tool and finish surface type processing of optical parts, and has the characteristics of high accuracy, high repeatability, easiness in operation, high efficiency and the like. Compared with the traditional aspheric optical part processing method, the numerical control lathe optical processing not only can meet the requirements in time, efficiency and cost, but also can finish the processing of metal such as gold, copper, nickel and the like and aspheric optical surfaces such as gold, copper, nickel and the like. Meanwhile, the method can also solve the technical problem of ultraprecise processing of complex aspheric surface curved surface parts, such as free curved surfaces, elliptic curved surfaces, diffraction surfaces, off-axis aspheric surfaces and other optical parts, which cannot be solved by the traditional aspheric surface optical part processing method.

The ultra-precision machining of optical elements such as complex aspheric surfaces, off-axis aspheric surfaces and the like can be realized by adopting a single-point diamond numerical control turning machine tool. Therefore, the single-point diamond numerical control turning machine is adopted to carry out optical processing, and optical surface processing can be carried out according to different materials and different optical surface types. Wherein, different materials include but not limited to PMMA, hydrophilic acrylate, hydrophobic acrylate, etc., different surface types include but not limited to sphere, aspheric surface, and aspheric surface includes complex curved surface, diffraction surface, etc. The single-point diamond numerical control turning machine tool is adopted for processing, so that the processing error can be greatly reduced, and the shape error can be less than 0.1 mu m.

S22: actually measuring the optical surface of the artificial lens obtained by processing by adopting a contact type or a non-contact type to obtain the profile data of the actually measured surface;

the step can be used for measuring the processed optical profile so as to restore the processed surface type, evaluating the error of the processed surface type by actually measuring the surface type profile data and judging the processing accuracy. Specifically, the measurement mode may be contact measurement or non-contact measurement. Contact measurement can be used for acquiring and analyzing the existing different surface profiles. By adopting non-contact measurement and utilizing a laser interference principle or a white light interference principle, the whole profile surface can be obtained and analyzed to obtain the deviation of the whole processing surface.

S23, performing mathematical modeling based on the actually measured surface profile data, and performing inversion to generate an optical surface actual model;

for intraocular lenses with different optical parameters, different optical surface types are realized. Such as spherical, aspherical; the aspheric surface can be a compound curved surface, a diffraction surface or a superposition combination of a plurality of surface types. Different optical surface types may correspond to different optical surface type object models. The embodiment adopts a profile curve to characterize an optical profile actual model.

The process of mathematical modeling is further elaborated upon by the detailed description below.

wherein z is the optical surface rise value, k is the conic coefficient, c is the curvature, is the reciprocal of the radius of curvature, r is the radial distance of a point on the lens from the y-axis, a₂、a₄、a₆… are aspheric coefficients. The constructed aspheric surface is an even-order aspheric surface, and when the conical coefficient k and the aspheric coefficient are 0, the optical surface formed by the equation is considered to be a spherical surface; otherwise, it represents an aspheric surface.

If the optical surface type is a toric surface, determining the surface type curve as follows:

wherein Z is the rise of the toric surface, c_x，c_yThe curvatures of two toric meridians are respectively inverse of the curvature radius, k_x、k_yIs the conic coefficient of the principal meridians of the two toric surfaces, r is the axial distance from the center of the lens, and θ is the meridian angle. In the plane type, when k is_x＝0，k_yWhen 0, the compound curved surface may have a spherical surface characteristic; when k is_xNot equal to 0, or k_yNot equal to 0, or k_x≠0，k_yWhen not equal to 0, the surface type is considered to be a compound curved surface with aspheric surface characteristics.

If the optical surface is a diffractive surface, the diffractive surface can be divided into two surfaces, one surface is a basic aspheric surface, and the other surface is defined as a surface determined by the step height, the zone radius, and the like, and the surfaces are superposed on the aspheric surface to form the whole diffractive optical surface. The diffraction surface has various mathematical models according to different ring zone radii and step heights. For example: the step heights are the same, and the ring belt radiuses are the same; or the ring belt radius is the same, the step heights are different, and the like, so that different superposed diffraction surfaces are formed according to different energy distributions, diffraction efficiencies and the like. Therefore, the mathematical model of the diffractive optical surface can be various, and will not be described in detail.

If the optical surface type is a diffraction surface type with a toric characteristic. The surface type can be a complex surface type combining an aspheric surface, a compound curved surface and a diffraction curved surface, and different optical characteristics can be realized from the aspect of characteristics of the artificial lens.

S24: judging whether the optical surface type actual model meets the surface type control requirement or not; if the optical surface type actual model does not meet the requirement, optimizing one or more parameters in the optical surface type target model, determining the optimized optical surface type target model, and returning to execute the step S21 until the optical surface type actual model meets the surface type control requirement;

by inverting the profile of the machined surface type, the original profile in either direction or multiple directions can be taken, preferably over the entire measurement range. Determining parameters after the surface fitting, wherein the parameters can comprise: radius of curvature, aspheric coefficients, rise value deviation at different apertures, total face shape deviation RMS (root mean square), or any combination thereof. Judging whether the deviation between the actually fitted surface type and the surface type to be achieved is smaller than the deviation requirement or not, and if so, judging that the surface type machined by the lathe meets the surface type control requirement; otherwise, the surface type control requirement is not met. For example, when the rise value deviation of the artificial lens actual surface at different apertures is less than or equal to a preset value, the optical surface type actual model is considered to meet or satisfy the surface type control requirement, otherwise, the optical surface type actual model is considered not to meet the surface type control requirement. For another example, when the total surface deviation RMS (root mean square value) of the actual surface of the intraocular lens is less than or equal to the predetermined value, the actual optical surface model is considered to meet or satisfy the surface control requirement, otherwise, the actual optical surface model is considered not to meet the surface control requirement. For another example, when the rise value deviation of the actual surface of the intraocular lens at different apertures and the whole surface deviation RMS are both less than or equal to corresponding preset values, the actual optical surface model is considered to meet or satisfy the surface control requirement, otherwise, the actual optical surface model is considered not to meet the surface control requirement.

S25: judging whether the artificial lens finally meeting the surface type control requirement reaches a preset performance index; if the preset performance index is not met, model compensation adjustment optimization is required, and the execution returns to S11 until the artificial lens meets the preset performance index.

In general, the manufacturing process of an intraocular lens includes many steps, and different manufacturing processes have a great influence on the surface shape change and even the optical performance. For this reason, in addition to achieving a controlled profile during processing, it is necessary to simultaneously consider the final effect on the optical properties of the intraocular lens after all manufacturing steps. For example, hydration processes, injection molding processes, temperature changes, etc. may have an effect on the optical properties.

In addition to the controllability of the machined surface type, factors influencing the optical performance in the subsequent manufacturing process are comprehensively considered. The performance index of the artificial lens meets the preset performance index through the measurement of the optical performance and the repeated iteration process. And the iteration of the performance index is mainly realized by continuously iterating and optimizing the surface type in the manufacturing process. The influence of the manufacturing process on the surface type change of the model is taken into consideration, and the initially established model is repeatedly iterated in an optical model iteration optimization mode until the optical performance of the model reaches the preset performance index.

The preset performance index can be any one or any combination of the following: spherical aberration, astigmatism, chromatic aberration. Taking spherical aberration as an example, the specific way of judging that the performance index is reached in this step may be: judging whether the spherical aberration of the intraocular lens processed according to the method is less than or equal to a preset spherical aberration threshold value or not, and if the spherical aberration of the intraocular lens is less than or equal to the preset spherical aberration threshold value, judging that the spherical aberration of the intraocular lens reaches a preset performance index; and if the spherical aberration of the artificial lens is larger than a preset spherical aberration threshold value, judging that the preset performance index is not reached.

In the embodiment, the surface form deviation is obtained, inversion is carried out on the surface form deviation by using a least square method according to the deviation between actual machining and theoretical surface form, and a final compensation model is fed back to a lathe for machining until the surface form deviation after final compensation machining meets controllable requirements. The following describes a specific implementation process of the method for performing optimization correction by using the least square method.

The basic idea of least squares curve fitting is: and the fitting curve which minimizes the sum of squares of errors of all the data points and the fitting points is the least square fitting curve. For a given set of data { (X)_i,Y_i) (i-1, 2, …, m), and if the fitted curve model is y-f (X), the ith error distance is f (X)_i)-Y_iThe sum of the squares of all points is:

further, a parameter corresponding to the minimum value of the sum of squares is obtained to obtain a fitting curve f (X)_i)。

The process of correcting the model mainly comprises the following steps:

determining a function model of the fitted curve;

the mathematical model to be corrected may be an aspheric surface, a compound curved surface, a diffractive curved surface or other complex optical surface type.

Determining solution parameters of a normal equation;

suppose a known data point (r)_i，z_i) Z is a polynomial composed of all aspheric coefficients with degree not exceeding m, and the polynomial is decomposed: z ═ H (r) + a_kr^k

The aspheric surface is assumed to be a quadric surface, and the curvature of the center point is c₀Coefficient of quadric surface of k₀Taking the point P of the edge₁(r₁，z₁) And an intermediate point P₂(r₂，z₂) And the coefficients of the remaining terms are 0, the following equation is obtained:

can obtain R₀＝1/c₀And k₀Value and take R e (0.8R)₀，1.2R₀)，k∈(0.8k₀，1.2k₀) The value ranges of R and k are defined as follows.

Now the inverse calculation is performed for the aspheric coefficients in the Z equation,

order to

So that

Solving partial derivative of the above formula and order

Then there is a change in the number of,

the collected data can be rapidly processed by a computer to obtain a corrected model, and correction optimization is performed by combining the numerical difference between the model and the actual sampling point to finish data correction.

And measuring the corrected surface shape until the requirement of the preset performance index is met by measuring the final optical performance of the artificial lens, and finishing the iteration process after the requirement is met. Otherwise, the model needs to be iteratively optimized according to data feedback in the process and by combining the performance indexes until the requirement of the preset performance indexes is met. Referring to fig. 3, a schematic diagram of an embodiment of a method of manufacturing an intraocular lens provided herein is shown.

The method for manufacturing the artificial lens provided by the embodiment has the following technical effects:

(1) the intraocular lens changes in the actual surface type, and the embodiment combines the principle of the least square method to perform profile inversion on the data sampling points, so that the final design output result can well cover the parameter values input by the design through compensation analysis;

(2) the optical processing of the numerical control lathe is applied to the production and manufacturing process of the artificial lens, and the realization of precise surface type can be well provided from a manufacturing source.

(3) The precision optical measurement is adopted to carry out actual measurement on the product processed by the numerical control optics, and certain feedback is given according to the measurement result, so that a certain basis is provided for the establishment of a mathematical model, and the optical performance of the product is further improved.

(4) And (4) establishing a mathematical model of the profile of the artificial lens according to the surface type measurement result of the artificial lens and the related surface type characteristics. The mathematical model provides a premise for subsequent iterative optimization by establishing different optical surface types according to different optical performance requirements and accurately expressing the optical surface types by using the mathematical model.

(5) Through continuous optimization iteration of the established mathematical model until the technical indexes of the product performance of the intraocular lens are met, the realization of good accurate surface shape control and high yield and quality can be achieved.

(6) The present invention is not limited to spherical and aspherical optical surface types, and can be applied to an asymmetric ellipsoidal surface and a diffractive optical surface. Also, the present invention is not limited to any material, and can be applied to both hard and soft materials. Therefore, the application can meet the requirement of personalized design for different optical designs and different optical surface types.

The following is a non-limiting example that specifically illustrates the implementation of the present application. Table 1 shows the basic indices of the intraocular lens.

TABLE 1

Through the basic indexes of the artificial lens, the artificial lens is planned to comprise two optical surfaces, in order to meet the technical index requirements, the spherical aberration within the aperture range of 5mm is 0 μm, and the technical index is realized by an aspheric surface, wherein the front surface can be an aspheric surface, the back surface can be a spherical surface, or the front surface can be a spherical surface, the back surface can be an aspheric surface, or the front surface and the back surface can be both aspheric surfaces. In this example, the front surface is selected to be spherical and the back surface to be aspherical. The basic parameters of both optical surfaces are shown in table 2.

TABLE 2

Taking the aspherical intraocular lens as an example, the intraocular lens consists of two optical surfaces. Where the anterior surface is spherical and the posterior surface is a higher order aspheric surface. By adopting the optical processing, optical measurement and mathematical model establishing method provided by the application, the adjustment and iterative optimization of the established surface model are carried out according to the actual processing process error and the factors possibly influencing the surface model in the subsequent manufacturing process, and the aim is to realize the accurate control of the spherical aberration under the large aperture of the single-focus artificial lens, thereby improving the optical performance of the artificial lens under the dark environment.

Likewise, the method is not limited to this profile and this IOL design, but is also applicable to the diffractive optical surfaces of toric, multifocal, EDOF IOLs that form the optical characteristics of astigmatic IOLs.

And inputting the obtained optical parameters into a processing file, and respectively processing two surfaces of the artificial lens. In this embodiment, the front surface sphere is processed and inspected, and the parameters involved in the processing include the optically effective aperture, the radius of curvature, and other mechanical characteristics.

Spherical optical surface machining and measurement are relatively simple optical surface machining, and the quality of a machined surface can be evaluated through surface shape errors. In this example, the rise difference at different apertures is used to estimate the profile error, and fig. 4 shows a schematic diagram of the deviation between the actual input profile in a certain direction and the profile obtained after the test, and at an aperture of 5mm, the profile deviation is 1 μm, and the profile deviation exceeds the control range. Figures 5-6 show a comparison of interference patterns with deviations from the simulated theoretical design values and the actual process measurements.

The machining process generally has large surface shape deviation, the deviation can be reduced to the minimum by performing model compensation adjustment for several times, such as curvature radius, cutter center difference, optical surface shape difference and the like, and certain compensation needs to be performed in the machining process to ensure that the machining error is minimized and the surface shape accuracy is ensured. The deviation of the surface shape in the processing process can be obtained from fig. 5-6, the deviation of the surface shape measured after processing and the designed surface shape is positive, the processing error caused by the influence of other factors such as the temperature, the personnel operation and the like in the material and the processing process is mainly concentrated at a large aperture of 5mm-6mm, and the contribution of the large aperture to the spherical aberration is as follows: the spherical aberration is relatively increased by 0.063 lambda. The main advantage of aspheric surfaces is the quality of the image at large apertures, so achieving a precise aspheric surface is of great interest for intraocular lens products. To achieve accurate non-spherical, the surface shape deviation generated in the production and manufacturing process needs to be further controlled and iteratively optimized.

After measurement, any one or more original contours on the curved surface can be obtained, the points on the contours are analyzed, the established model is processed in a data process by combining the curve equation inversion theory and the curve equation inversion method, and as shown in a schematic diagram of processing deviation and fitting data curve of FIG. 7, a model curve equation is obtained as

Wherein c is close to 0; k is 0; a2 ═ 2.96 e-5; a4 ═ 9.497 e-8; as shown in the fitted residual diagram of fig. 8.

According to the fitting result of the deviation curve, the original curve contour to be compensated is combined for compensation, an ideal optimized curve can be finally obtained, and finally an optical surface compensation model is adjusted to be,

wherein c is 0.053; k is 0; a2 ═ 2.96 e-5; a4 ═ 9.497 e-8;

and evaluating the interference fringes of the compensated result, wherein the interference fringes are very close to an ideal design value as shown in a schematic diagram of the interference fringes after compensation in figure 9, and the controllable requirement of the surface type is met.

The back surface is aspheric and the same machining principle and analysis method can be used. For aspheric surface processing, more processing parameters may need to be planned than for spherical surface processing. According to the aspheric surface type processing designed in this embodiment, the main parameters to be converted into the input processing are: radius of curvature, conic coefficient, corresponding higher order aspheric coefficient. An original profile is obtained by measuring the processed optical surface type, and points on the original profile are subjected to curve inversion and fitting calculation, so that a curve schematic diagram of deviation between the theoretical aspheric surface design and the actual surface type as shown in fig. 10 is finally obtained, the deviation between the theoretical design and the actual surface type changes along with the change of the aperture, the deviation at the maximum aperture is 2.2 μm, the change trend at the position of 5mm-6mm is more obvious, and the change of the surface type deviation is reflected in the change of optical aberration as shown in fig. 11-12. It is clear that the profile deviations caused in this process are beyond the profile control requirements. Fig. 11 shows that the interference fringe pattern PV contributed by the theoretically designed surface pattern is 2.5544 λ, and PV of the actually processed and detected surface pattern is 2.8357 λ, as shown in fig. 12. For this reason, since the influence of the surface shape deviation on the optical aberration is obvious, it is necessary to compensate and correct the generated surface shape deviation model.

FIG. 13 is a schematic diagram showing the difference between the actual deviation point of the process and the curve generated by fitting the data, and compensating the mathematical model thereof, the difference between the actual fitted curve and the process deviation being shown in FIGS. 14-15. Fig. 14 shows a graph of process variation and fitted data, and fig. 15 shows a graph of fitted curve variation.

The model after the final surface shape compensation is as follows:

c is close to 0, a3 ═ 2.97e-6,

wherein c is 0.042, k is 0.27, and a3 is 1.088 e-05.

And then lathe processing and measurement back calculation are carried out through the modified model, and finally the surface shape generated on the back surface is very close to the actual processing input value, as shown in figure 16. Fig. 16 shows a schematic diagram of the interference fringes after model correction. It can be seen from this that the surface shape of the soft lens changes at 4.5mm to 6.0mm, the spherical aberration at large aperture varies due to the deviation of the surface shape, and the most critical embodiment is also at large aperture for the aspherical lens, so it is necessary to control the aberration at large aperture, and controlling the change of the surface shape deviation becomes the key to control the accuracy of spherical aberration.

After the processed surface type can meet the surface type control requirement, the artificial lens can be subjected to other manufacturing processes, and the artificial lens subjected to other processes can be subjected to corresponding optical performance evaluation, such as focal power, spherical aberration and the like. And evaluating the performance of the artificial lens, and if the performance of the artificial lens meets the preset performance index, determining that the artificial lens meets the performance index requirement. Otherwise, the performance improvement in the manufacturing process continues, and the optical performance of the intraocular lens is improved primarily by the modification and control of its optical profile, which modification and compensation of the profile over the process has an effect on its optical performance. Therefore, the relationship between the surface type and the performance of the product needs to be explored by combining the surface type iteration, and the performance of the product can meet the performance index requirement through continuous iteration optimization of the surface type according to factors which possibly influence the surface type and the performance in the manufacturing process.

For example, a finished intraocular lens can meet the requirements of surface shape control, but after the artificial lens is influenced by processes such as hydration, temperature, injection molding and the like, the artificial lens has a large influence on the optical surface shape. In this embodiment, the power of the final intraocular lens after all manufacturing processes shifts from 20.0D to 20.3D, the spherical aberration at the aperture of 5mm changes to-0.15 μm, which is far beyond the controllable range of +/-0.05 μm, so that the planned surface profile needs to be iteratively optimized to meet the performance requirements of the intraocular lens after all manufacturing processes.

Because the intraocular lens is composed of the front optical surface and the back optical surface, and the two optical surfaces jointly contribute to the optical power and the spherical aberration, when the surface type iterative optimization is carried out, the surface type errors of the front surface and the back surface after all manufacturing processes need to be analyzed and determined, and then model iteration is carried out on one optical surface or two optical surfaces. Thus, iterations can be made on only one optical surface, e.g., the front surface, or the back surface. Of course, iteration of one of the optical surfaces can be used to compensate and balance the surface type deviation change of the other surface, so as to achieve effective control of the optical parameters at the large aperture of the whole intraocular lens. The iterative process is to determine the surface shape deviation caused by other processes after optical processing through data collection, and uniformly perform feedback and iteration until the optical performance of the intraocular lens meets the performance index requirement.

The results of the profile deviations of the front and back surfaces are shown in fig. 17-18. Fig. 17 shows a schematic diagram of the front surface profile variation, and fig. 18 shows a schematic diagram of the rear surface profile variation.

After the two surfaces are deformed, the spherical aberration is changed from 0 μm to-0.15 μm because the two surfaces contribute together. FIGS. 19-20 show that different PV values are exhibited due to variations in the profile. For the precise non-sphere, the deformed surface shape of the non-sphere needs to be compensated, so that the non-sphere is infinitely close to the designed surface shape.

According to the deviation generated in the actual process, the surface type is compensated and corrected by the method adopted by the application. For example, the measurement optimization is only carried out on the front surface, the front surface is enabled to bear the deformation of the rear surface, namely the over-compensation is carried out, and the Z value at the maximum aperture position after the surface deformation is increased, so that the spherical aberration at the large aperture position is changed to be close to the design value. The final result is shown in the model optimization result diagram of fig. 21.

By optimizing the surface type of the back surface and combining the principle of the fitting curve, the final compensation curve is as follows:

where c is 1/20.08, K is 0, a2 is-5.699 e-05, a3 is 5.664e-07, and the final curve equation is obtained by substituting the equations. The front surface is kept unchanged, the focal power of the artificial lens can reach 20+/-0.1D after verification, the spherical aberration at the aperture of 5mm can reach 0+/-0.02 mu m, accurate control and optimization can be achieved under the large aperture of the aspheric artificial lens, and the performance index can meet the requirement of technical indexes.

In the above example, the aspheric surface coefficients are not limited to the example, and may be preferentially selected according to the actual process.

Similarly, the method provided by the application can be applied to other compound curved surfaces, diffraction element processing measurement and model establishment and model adjustment compensation.

In addition, the present application provides an intraocular lens manufactured using any of the above-described intraocular lens manufacturing methods.

In summary, the intraocular lens and the manufacturing method thereof provided by this embodiment overcome the defect of increased surface shape errors caused in the processing process and the actual manufacturing process by adopting the technical means of digital control lathe optical processing, precise optical measurement, precise mathematical model establishment and iterative optimization, achieve control compensation of precise surface shape, further improve the accuracy and stability of design output conversion, and effectively improve the optical quality of the intraocular lens at the full optical aperture. In addition to the traditional simple spherical surface, complex optical surface designs are used in modern IOLs to control the locally transmitted wavefront, by which the IOL can precisely achieve a variety of optical performance requirements to very detailed visual acuity, contrast sensitivity, and depth of focus. The present invention provides a method by which these complex surface designs can be realized in practice.

In addition, the method provided by the application applies the optical processing of the numerical control lathe to the production and manufacturing process of the artificial lens, and can well realize the precise surface type from the manufacturing source. The precision optical measurement is adopted to carry out actual measurement on the product processed by the numerical control optics, and certain feedback is given according to the measurement result, so that a certain basis is provided for the establishment of a mathematical model, and the optical performance of the product is further improved. And (4) establishing a mathematical model of the profile of the artificial lens according to the surface type measurement result of the artificial lens and the related surface type characteristics. The mathematical model provides a premise for subsequent iterative optimization by establishing different optical surface types according to different optical performance requirements and accurately expressing the optical surface types by using the mathematical model. And (3) combining the least square principle to perform contour inversion on the data sampling points, and performing compensation analysis, so that the final design output result can well close the parameter value of the design input. Through continuous optimization iteration of the established mathematical model until the technical indexes of the product performance of the intraocular lens are met, the realization of good accurate surface shape control and high yield and quality can be achieved.

The intraocular lens and the method for manufacturing the same according to the present application are applicable to any of asymmetric ellipsoidal surfaces and diffractive optical surfaces, as well as spherical and aspherical optical surface types. Also, the present invention is not limited to any material, and can be applied to both hard and soft materials. Therefore, the application can meet the requirement of personalized design for different optical designs and different optical surface types.

While various embodiments of aspects of the present application have been described for purposes of this disclosure, they are not to be construed as limiting the teachings of the present disclosure to these embodiments. Features disclosed in one particular embodiment are not limited to that embodiment, but may be combined with features disclosed in different embodiments. For example, one or more features and/or operations of a method according to the present application described in one embodiment may also be applied, individually, in combination, or in whole, in another embodiment. It will be understood by those skilled in the art that there are many more alternative embodiments and variations possible and that various changes and modifications may be made to the system described above without departing from the scope defined by the claims of the present application.

Claims

1. A method of manufacturing an intraocular lens for precise face control, comprising the steps of:

s11: acquiring an optical surface type target model of the artificial lens, and carrying out optical processing on the basis of the optical surface type target model to obtain the artificial lens;

s12: actually measuring the optical surface of the artificial lens to obtain actually measured surface profile data;

s13: performing mathematical modeling based on the actually measured surface profile data, and performing inversion to generate an optical surface actual model of the intraocular lens;

s15: judging whether the artificial lens meeting the surface type control requirement reaches a preset performance index or not; and if the preset performance index is not met, performing model compensation adjustment optimization, and returning to execute S11 until the artificial lens meets the preset performance index.

2. The method for manufacturing an intraocular lens according to claim 1, further comprising, before the step of obtaining the optical surface type object model of the intraocular lens at step S11: and determining an optical surface type target model according to the technical indexes of the artificial lens.

3. The method of manufacturing an intraocular lens according to claim 1 or 2, wherein the step S13 of performing mathematical modeling based on the actually measured surface profile data, the inverse generation of the actual model of the optical surface of the intraocular lens comprising:

4. The intraocular lens manufacturing method according to claim 3, wherein performing data inversion to generate an optical surface actual curve using the actually measured surface profile data as fitting data of the surface curve comprises:

5. The intraocular lens manufacturing method of claim 3, wherein determining a profile curve from the optical profile target model comprises:

if the artificial lens is a spherical or aspherical artificial lens, the optical surface type is correspondingly spherical or aspherical, and the determined surface type curve is as follows:

wherein Z is the rise of the toric surface, c_x，c_yThe curvatures of two toric meridians are respectively inverse of the curvature radius, k_x、k_yThe conic coefficients of the principal meridians of the two toric surfaces, r is the axial distance from the center of the lens, and theta is the meridian angle;

6. The method of claim 1 or 2, wherein the optical surface type of the intraocular lens comprises a first optical surface type and a second optical surface type distributed anteroposteriorly, wherein the optimization of one or more parameters in the optical surface type object model is performed, and wherein the determination of the optimized optical surface type object model comprises:

and performing iterative optimization compensation on the established mathematical model according to the difference between the actual parameter and a preset performance index, wherein the iterative optimization compensation comprises the optimization of one or more parameters in the first optical surface type and/or the second optical surface type.

7. The intraocular lens manufacturing method according to claim 1 or 2, wherein obtaining an optical surface type target model and performing optical processing based on the optical surface type target model comprises:

8. The method of manufacturing an intraocular lens according to claim 1 or 2, wherein the actual measurement of the optical profile of the intraocular lens in S12 is performed, and the obtaining of the actual measured profile data comprises:

9. The method for manufacturing an intraocular lens according to claim 1 or 2, wherein the parameters required for the reactive surface type control include: radius of curvature, aspheric coefficients, rise value deviation at different apertures, total profile deviation RMS, or any combination thereof.

10. The method of claim 9, wherein determining whether the optical surface model meets the surface control requirement comprises:

judging whether the rise value deviation or/and the whole face shape deviation RMS at different apertures of the optical face shape actual model is smaller than or equal to a preset value, if the rise value deviation or/and the whole face shape deviation RMS at different apertures of the optical face shape actual model is smaller than or equal to the preset value, judging that the optical face shape actual model meets the face shape control requirement; and if the rise value deviation or/and the whole face shape deviation RMS at different apertures of the optical face shape actual model is/are larger than the preset value, judging that the optical face shape actual model does not meet the face shape control requirement.

11. The method of manufacturing an intraocular lens according to claim 1 or 2, wherein the predetermined performance criteria comprises any one or any combination of: focal power, spherical aberration, astigmatism, chromatic aberration.

12. Intraocular lens, characterized in that it is manufactured with the method for manufacturing an intraocular lens according to any one of claims 1 to 10.