CN117008358A - An evaluation method and design method for double-sided progressive multifocal lenses - Google Patents
An evaluation method and design method for double-sided progressive multifocal lenses Download PDFInfo
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- G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
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- G02C7/02—Lenses; Lens systems ; Methods of designing lenses
- G02C7/06—Lenses; Lens systems ; Methods of designing lenses bifocal; multifocal ; progressive
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Abstract
本发明公开了一种双面渐进多焦点镜片的评价方法及设计方法，评价方法包括：在镜片后表面设置多个离散样本点Pbi；在瞳孔圆周上取n对光线起点；以平行于瞳孔中心向一样本点Pbi的方向，确定第一对光线起点到镜片的后表面的两条光线，并光线追迹得到其与镜片前表面的两交点以及从两交点的出射矢量s1和s2；获得两条出射光线的交点及该交点到该样本点的距离，将该距离的倒数作为第一对光线起点的切面光焦度；获得同一个样本点对应的其他对光线起点的切面光焦度；以该样本点对应的各个切面光焦度中的最大值和最小值的差值作为其像散值；得到每个样本点对应的像散值，仿真镜片的像散分布。本发明能更准确地反映使用镜片时的视觉效果。
The invention discloses an evaluation method and a design method for a double-sided progressive multifocal lens. The evaluation method includes: setting multiple discrete sample points P bi on the rear surface of the lens; taking n pairs of light starting points on the pupil circumference; With the center in the direction of a sample point P bi , determine the two rays from the starting point of the first pair of rays to the rear surface of the lens, and trace the rays to obtain the two intersection points with the front surface of the lens and the exit vectors s1 and s2 from the two intersection points; Obtain the intersection point of the two outgoing rays and the distance from the intersection point to the sample point, and use the reciprocal of the distance as the tangential power of the starting point of the first pair of rays; obtain the tangential power of the starting point of other pairs of rays corresponding to the same sample point ; Use the difference between the maximum value and the minimum value of the power of each section corresponding to the sample point as its astigmatism value; obtain the astigmatism value corresponding to each sample point, and simulate the astigmatism distribution of the lens. The present invention can more accurately reflect the visual effect when using the lens.
Description
Technical Field
The application relates to the field of optical lenses, in particular to an evaluation method and a design method of a double-sided progressive addition lens.
Background
Progressive addition lenses, also known as progressive addition lenses, can solve the problem of different power for long-distance, intermediate and near-distance objects, and are also an important choice for vision correction in teenagers. The accurate evaluation of progressive addition lenses is important for their design and post-processing, and is a precondition for obtaining lenses with optimal visibility.
In the prior art, the method for evaluating the progressive addition lens is generally only suitable for measuring and evaluating the processed lens, and the position relationship between the lens and the eyeball is considered in the evaluation process. The Chinese patent with publication number of CN103123420 proposes that optical parameters of a double-sided free-form surface lens are calculated through sagittal height distribution data of the front surface and the rear surface of the lens, and finally optical power and astigmatism distribution of the combined lens are deduced.
The above disclosure of background art is only for aiding in understanding the inventive concept and technical solution of the present application, and it does not necessarily belong to the prior art of the present patent application, nor does it necessarily give technical teaching; the above background should not be used to assess the novelty and creativity of the present application in the event that no clear evidence indicates that such is already disclosed prior to the filing date of the present patent application.
Disclosure of Invention
The application aims to provide an evaluation method and a design method of a double-sided progressive multi-focus lens, which simulate a plurality of light ray starting points at the pupil circumference position to calculate the astigmatic distribution of the lens and reflect the visual effect when the lens is used more accurately.
In order to achieve the above purpose, the application adopts the following technical scheme:
a method of evaluating a double-sided progressive addition lens, comprising the steps of:
determining the mirror structures of the front surface and the rear surface of the lens to be analyzed and the refractive index of the material of the lens to be analyzed;
providing a plurality of discrete sample points P on the rear surface of the lens bi Wherein i is more than or equal to 1 and less than or equal to j, and j is the integer number of sample points;
determining the center position of the pupil according to the preset glasses relationship for wearing glasses; determining the pupil circumference according to the preset pupil diameter;
taking n pairs of light starting points on the circumference of the pupil, wherein each pair of light starting points is symmetrical relative to the center of the pupil, and n is the integer number of the pairs of light starting points;
for each sample point P bi Its astigmatism is determined by:
to the sample point P in parallel with the pupil center bi Determining two rays from a first pair of ray origins to the rear surface of the lens and ray tracing to obtain their respective intersection points P with the front surface of the lens fi-1 And P fi-2 And an intersection point P fi-1 The exit vector s1 at the intersection point P fi-2 An exit vector s2 at;
obtaining the intersection point P of two rays of the outgoing vectors s1, s2 cross-i1 Obtaining the intersection point P cross-i1 To the sample point P bi And taking the reciprocal of the distance as the focal power of the first pair of light sources
Obtaining the same sample point P bi The focal power of the tangent plane corresponding to the starting point of other light raysTo->
Determining the same sample point P bi Maximum and minimum values in the corresponding individual section powers and taking the difference as the sample point P bi Corresponding astigmatism Δx' bi ；
And obtaining an astigmatism value corresponding to each sample point, simulating the astigmatism distribution of the lens, and taking the astigmatism distribution as a basis for evaluating the lens.
Further, any one or a combination of the foregoing technical solutions, determining a contour line of a preset astigmatism threshold in the astigmatism distribution;
estimating the area of the region within the contour line of the preset astigmatism threshold;
and if the area of the area within the high lines is smaller than a preset area threshold value, evaluating that the lens is unqualified.
Further, according to any one or a combination of the above-mentioned embodiments, the intersection point P of the two light rays of the emission vectors s1, s2 is calculated by the following formula cross-i1 ：
Normal＝s1×s2，
Normal_1＝s1×Normal，
Normal_2＝s2×Normal，
P f-3 ＝P f-2 -P f-1 ，
P cross-i1 ＝P f-1 +s1·(P f-3 ·Normal_2)/(s1·Normal_2)，
Wherein s1 is the emergent vector of the first emergent ray from the front surface of the lens, s2 is the emergent vector of the second emergent ray from the front surface of the lens, normal, normal_1 and normal_2 are all intermediate calculated variables, and P fi-1 Representing the intersection point of the first emergent ray and the front surface of the lens, P fi-2 Represents the intersection point of the second emergent ray and the front surface of the lens, and represents the intersection point P f-2 To the intersection point P f-1 Distance, P cross-i1 The intersection of the emission vectors s1, s2 is shown.
Further, according to any one or a combination of the foregoing aspects, an intersection point P of two rays from a first ray origin to a rear surface of the lens and a front surface of the lens is obtained by ray tracing by fi-1 And P fi-2 ：
To the sample point P by the pupil center bi And making a first light ray and a second light ray parallel to the virtual light ray, wherein the first light ray and the second light ray respectively pass through a first light ray starting point;
determining the first light according to the mirror structure of the rear surface of the lensIntersection point P of line and the rear surface bi-1 And the intersection point P bi-1 Normal line ofAnd determining an intersection point P of the second light ray with the rear surface bi-2 And the intersection point P bi-2 Normal line of
Determining the direction of the refracted ray after the first ray enters the lensAnd the direction of the refracted ray of the second ray after entering the lens +.>
Determining an intersection point P in combination with the mirror structure of the front surface of the lens bi-1 Direction of refracted rayIntersection point P of the ray of (C) with the front surface fi-1 And determining the intersection point P bi-2 Refractive ray direction->Intersection point P of the ray of (C) with the front surface fi-2 。
Further, according to any one or a combination of the above-mentioned aspects, the refractive light direction of the first light after entering the lens is calculated according to the following formula
Wherein (1)> For the direction of the refracted ray after the first ray enters the lens, I1 is the refractive index of the material of the lens, < >>For the direction of the first light passing through the start of one of the light rays,/->Is the intersection point P bi-1 Normal vector is positioned;
and calculating the direction of the refracted ray after the second ray enters the lens according to the following formula
Wherein (1)> For the direction of the refracted ray after the second ray enters the lens, I1 is the refractive index of the material of the lens,For the direction of the second light passing through the start of another light>Is the intersection point P bi-2 Normal vector.
Further, any one or a combination of the above-mentioned aspects, the intersection point P is determined by fi-1 The exit vector s1 at the intersection point P fi-2 Exit vector atAn amount s2;
determining an intersection point P with the front surface of the lens according to the mirror structure of the front surface fi-1 Normal line ofDetermining an intersection point P with the front surface fi-2 Normal line of the department->
Determining the medium refractive index I2 of the environment in which the lens is positioned, and calculating the intersection point P by the following formula fi-1 Exit vector s1 at:
wherein (1)>s1 is the intersection point P fi-1 The emergent vector at the position, I2 is the medium refractive index of the environment where the lens is located, +.>Is the refractive ray direction after the first ray enters the lens, +.>Is the intersection point P fi-1 Normal vector is positioned;
the intersection point P is calculated by the following formula fi-2 Exit vector s2 at:
wherein (1)>s2 is the intersection point P fi-2 The emergent vector at the position, I2 is the medium refractive index of the environment where the lens is located, +.>For the direction of the refracted ray after the second ray enters the lens,Is the intersection point P fi-2 Normal vector.
Further, any one or a combination of the above-mentioned aspects may be applied to the method of obtaining the same sample point P bi The focal power of the tangent plane of each corresponding light ray starting pointTo->Thereafter, an average value of the tangential power is calculated as the sample point P bi A corresponding average optical power;
and obtaining the average focal power corresponding to each sample point, simulating the average focal power distribution of the lens, and taking the average focal power distribution as the basis for auxiliary evaluation of the lens.
Further, in the foregoing any one or combination of the foregoing any one or more embodiments, determining an average power value at a preset position in the average power distribution, where the preset position includes a far zone and a near zone, and if the average power of the near zone is 0 and the average power of the far zone meets a design target power value, evaluating that the lens is qualified.
Further, taking a point with a preset lens distance from the center of the rear surface of the lens as a pupil center position on the optical axis of the rear side of the lens according to any one or a combination of the above-mentioned technical aspects;
determining a plane in which the pupil circumference is located in a direction perpendicular to the optical axis;
the pairs of light starting points on the circumference of the pupil are more than six pairs, and more than 12 light starting points are distributed on the circumference of the pupil at equal intervals.
According to another aspect of the present application, there is provided a method for designing a dual-sided progressive addition lens, wherein the method for evaluating the lens according to any one or a combination of the above-mentioned technical solutions is used to obtain an astigmatism distribution of the lens;
and adjusting design parameters of the lens according to the astigmatism distribution until the astigmatism distribution of the lens meets a preset standard.
The technical scheme provided by the application has the following beneficial effects: considering the actual wearing state of a user, a plurality of light ray starting points are simulated at the pupil circumference position, and the actual situation of an object is observed closer to eyes, so that the obtained astigmatism distribution can theoretically reflect the actual visual effect of the user when the lens is used, and the accuracy of lens performance evaluation is improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to the drawings without inventive effort to those skilled in the art.
FIG. 1 is a flow chart of a method of evaluating a dual-sided progressive addition lens according to an exemplary embodiment of the present application;
fig. 2 is a schematic diagram of a pupil and lens optical system when a pair of eyes of a person wear glasses according to an exemplary embodiment of the present application;
FIG. 3 is a schematic view of a pupil circumference setup 6 of a light ray starting point according to an exemplary embodiment of the present application;
FIG. 4 is a schematic view of a lens back surface with a plurality of sampling points according to an exemplary embodiment of the present application;
FIG. 5 is a schematic illustration of the deflection of incident and outgoing light rays through a lens surface provided by an exemplary embodiment of the present application;
FIG. 6 is a schematic view of the optical path of two light rays through a lens passing through a pair of light ray origins and parallel to the pupil center in the direction of a sample point provided by an exemplary embodiment of the present application;
FIG. 7 is an astigmatism distribution diagram of a lens obtained using conventional surface shape simulation in accordance with an exemplary embodiment of the present application;
FIG. 8 is an astigmatism distribution diagram of the lens of FIG. 7 simulated by the lens evaluation method of the present application;
FIG. 9 is a graph of the power profile of the lens of FIG. 7 obtained by conventional surface shape simulation;
FIG. 10 is a graph of the power profile of the lens of FIG. 7 obtained by simulation using the lens evaluation method provided by the present application.
Wherein, the reference numerals include: 1-pupil, 2-lens, 21-lens back surface, 22-lens front surface, 3-first ray, 4-second ray.
Detailed Description
In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or device.
In one embodiment of the present application, there is provided a method of evaluating a double-sided progressive addition lens, see fig. 1, the method comprising the steps of:
determining the mirror structures of the front surface and the rear surface of the lens to be analyzed and the refractive index of the material of the lens to be analyzed;
referring to fig. 4, a plurality of discrete sample points P are provided on the rear surface of the lens bi Wherein i is more than or equal to 1 and less than or equal to j, and j is the integer number of sample points;
determining the center position of the pupil according to the preset glasses relationship for wearing glasses; determining the pupil circumference according to the preset pupil diameter;
referring to fig. 3, n light ray starting points are taken on the circumference of the pupil, each light ray starting point is symmetrical with respect to the center of the pupil, and n is an integer number of light ray starting point pairs;
for each sample point P bi Its astigmatism is determined by:
as shown in fig. 6, the sample point P is oriented parallel to the pupil center bi Determining two rays from a first pair of ray origins to the rear surface of the lens and ray tracing to obtain their respective intersection points P with the front surface of the lens fi-1 And P fi-2 And an intersection point P fi-1 The exit vector s1 at the intersection point P fi-2 An exit vector s2 at;
obtaining the intersection point P of two rays of the outgoing vectors s1, s2 cross-i1 Obtaining the intersection point P cross-i1 To the sample point P bi And taking the reciprocal of the distance as the focal power of the first pair of light sources
Obtaining the same sample point P bi The focal power of the tangent plane corresponding to the starting point of other light raysTo->
Determining the same sample point P bi Maximum and minimum values in the corresponding individual section powers and taking the difference as the sample point P bi Corresponding astigmatism Δx' bi ；
And obtaining an astigmatism value corresponding to each sample point, simulating the astigmatism distribution of the lens, and taking the astigmatism distribution as a basis for evaluating the lens.
The evaluation method of the double-sided progressive multi-focus lens provided by the application is characterized in that a plurality of light ray starting points are simulated at the pupil circumference position, and the light ray tracking method is used for calculating the astigmatism distribution of the lens.
In one embodiment of the application, the pupil and lens optical system is shown in fig. 2 when the eye wears the glasses. Wherein the rear surface 21 of the lens has a concave structure, the front surface 22 of the lens has a planar structure, and the refractive index of the lens 2 is I; taking a point, which is a preset lens eye distance from the center of the rear surface of the lens, as a pupil center position on the optical axis of the rear side of the lens 2, wherein the distance from the center of the pupil 1 to the rear surface of the lens 2 is 27mm as shown in fig. 2; the coordinates of the pupil center can be set as (0, -27), and the intersection point of a light ray passing through the pupil center and the rear surface of the lens is P b The intersection point of the front surface of the lens is P f 。
The plane in which the pupil circumference is located is determined in a direction perpendicular to the optical axis, and in this embodiment, a circle having a radius of 2mm in a direction perpendicular to the optical axis is used as the pupil circumference. The pairs of light starting points on the circumference of the pupil are more than six pairs, and more than 12 light starting points are distributed on the circumference of the pupil at equal intervals.
In this embodiment, referring to fig. 3, 6 light ray starting points are taken on the pupil circumference, each light ray starting point being symmetrical about the pupil center. The circles shown in fig. 3 are pupil circles on which 1 and 1-are a pair of light start points, 2 and 2-are a pair of light start points, 3 and 3-are a pair of light start points, 4 and 4-are a pair of light start points, 5 and 5-are a pair of light start points, and 6-are a pair of light start points.
Referring to fig. 6, a sample point P is oriented parallel to the pupil center bi Two rays of light from the first pair of rays to the rear surface 12 of the lens, namely the first ray 3 and the second ray 4 in fig. 6, are determined.
Referring to fig. 6, a sample point P is oriented parallel to the pupil center bi Two rays of light from the first pair of rays to the rear surface 12 of the lens, namely the first ray 3 and the second ray 4 in fig. 6, are determined.
The ray tracing process includes two key steps: solving the intersection point position of the light ray and the free-form surface; and secondly, solving the direction of the refracted ray. The Chinese patent application with publication number of CN113281903A provides a rapid iterative solving method for the intersection point position of light rays and free curved surfaces, and the method provided by the patent can obtain the intersection point P of two light rays from the first light ray starting point to the rear surface of the lens and the front surface 21 of the lens fi-1 And P fi-2 。
In the present embodiment, the intersection point P of the first light ray 3 and the second light ray 4, which are two light rays from the first light ray origin to the rear surface of the lens, and the front surface 21 of the lens is obtained by ray tracing fi-1 And P fi-2 ：
To the sample point P by the pupil center bi And making a first light ray 3 and a second light ray 4 parallel to the virtual light ray, wherein the first light ray 3 and the second light ray 4 respectively pass through a first light ray starting point;
determining the intersection point P of the first light ray and the rear surface according to the mirror surface structure of the rear surface of the lens bi-1 And the intersection point P bi-1 Normal line ofAnddetermining the intersection point P of the second light ray and the rear surface bi-2 And the intersection point P bi-2 Normal line of
Determining the direction of the refracted ray after the first ray enters the lensAnd the direction of the refracted ray of the second ray after entering the lens +.>
Determining an intersection point P in combination with the mirror structure of the front surface of the lens bi-1 Direction of refracted rayIntersection point P of the ray of (C) with the front surface fi-1 And determining the intersection point P bi-2 Refractive ray direction->Intersection point P of the ray of (C) with the front surface fi-2 。
In one embodiment of the application, referring to FIG. 5, the refractive ray direction after the first ray enters the lens is calculated according to the following formula
Wherein (1)> Is the direction of the refracted ray after the first ray enters the lens, I1 is a mirrorRefractive index of sheet material>For the direction of the first light passing through the start of one of the light rays,/->Is the intersection point P bi-1 Normal vector is positioned;
and calculating the direction of the refracted ray after the second ray enters the lens according to the following formula
Wherein (1)> For the direction of the refracted ray after the second ray enters the lens, I1 is the refractive index of the material of the lens,For the direction of the second light passing through the start of another light>Is the intersection point P bi-2 Normal vector.
In one embodiment of the application, the intersection point P is determined by fi-1 The exit vector s1 at the intersection point P fi-2 An exit vector s2 at;
determining an intersection point P with the front surface of the lens according to the mirror structure of the front surface fi-1 Normal line ofAnd determining and saidIntersection point P of front surface fi-2 Normal line of the department->
Determining the medium refractive index I2 of the environment in which the lens is positioned, and calculating the intersection point P by the following formula fi-1 Exit vector s1 at:
wherein (1)>s1 is the intersection point P fi-1 The emergent vector at the position, I2 is the medium refractive index of the environment where the lens is located, +.>Is the refractive ray direction after the first ray enters the lens, +.>Is the intersection point P fi-1 Normal vector is positioned;
the intersection point P is calculated by the following formula fi-2 Exit vector s2 at:
wherein (1)>s2 is the intersection point P fi-2 The emergent vector at the position, I2 is the medium refractive index of the environment where the lens is located, +.>For the direction of the refracted ray after the second ray enters the lens,Is the intersection point P fi-2 Normal vector.
In one embodiment of the present application, the intersection point P of the two rays of the exit vectors s1, s2 is calculated by the following formula cross-i1 ：
Normal＝s1×s2，
Normal_1＝s1×Normal，
Normal_2＝s2×Normal，
P f-3 ＝P f-2 -P f-1 ，
P cross-i1 ＝P f-1 +s1·(P f-3 ·Normal_2)/(s1·Normal_2)，
Wherein s1 is the emergent vector of the first emergent ray from the front surface of the lens, s2 is the emergent vector of the second emergent ray from the front surface of the lens, normal, normal_1 and normal_2 are all intermediate calculated variables, and P fi-1 Representing the intersection point of the first emergent ray and the front surface of the lens, P fi-2 Represents the intersection point of the second emergent ray and the front surface of the lens, and represents the intersection point P f-2 To the intersection point P f-1 Distance, P cross-i1 The intersection of the emission vectors s1, s2 is shown.
Calculating the intersection point P cross-i1 To the sample point P bi And taking the reciprocal of the distance as the focal power of the first pair of light sources
Repeatedly adopting the method to obtain the same sample point P bi The focal power of the tangent plane corresponding to the starting point of other light raysTo->And determining the same sample point P bi Maximum and minimum values in the corresponding individual section powers and taking the difference as the sample point P bi Corresponding astigmatism Δx' bi The method comprises the steps of carrying out a first treatment on the surface of the Astigmatic value Δx' bi The following formula can be used for expression:
then, the above method is repeatedly adopted to obtain the astigmatism values corresponding to other sample points, and the astigmatism distribution of the lens is simulated based on the astigmatism values corresponding to all sample points, as shown in fig. 8, and the astigmatism distribution is used as the basis for evaluating the lens: determining a contour line of a preset astigmatism threshold value in the astigmatism distribution; estimating the area of the region within the contour line of the preset astigmatism threshold; if the area of the area within the high lines is smaller than a preset area threshold value, evaluating that the lens is unqualified; and if the area of the area within the high lines is not smaller than a preset area threshold value, evaluating the lens to be qualified. In a typical evaluation rule, an area within-0.5 of the astigmatism value is an effective area, and, for example, in fig. 8, an area within-0.5 of the astigmatism contour is a conforming area. The larger the area within the 0.5 astigmatism contour, which means the better the lens performance, the different grades can also be rated, the grade of the lens being evaluated on the basis of the area within the-0.5 astigmatism contour.
In one embodiment of the present application, the proposed method for evaluating a dual-sided progressive addition lens includes determining an astigmatism value corresponding to each sample point, simulating an astigmatism distribution of the lens, and taking the astigmatism distribution as a basis for evaluating the lens, and determining an average optical power corresponding to each sample point, simulating an average optical power distribution of the lens, and taking the average optical power distribution as a basis for assisting in evaluating the lens:
in the present embodiment, the same sample point P is obtained bi The focal power of the tangent plane of each corresponding light ray starting pointTo the point ofThereafter, an average value of the tangential power is calculated as the sample point P bi A corresponding average optical power; obtaining an average optical power corresponding to each sample point, simulating an average optical power distribution of the lens, such asFig. 10 shows the result of this as a basis for assisting in evaluating the lens. The lens may be evaluated in the following manner:
and determining an average focal power value at a preset position in the average focal power distribution, wherein the preset position comprises a central local area, and if the average focal power of the lower part of the central local area is 0 and the average focal power of the upper part of the central local area accords with a design target focal power value, evaluating that the lens is qualified. For example, a lens with a designed power of 2.0 in the far-field area, a designed power of 0 in the near-field area and an add of 2.0 is taken as an example in fig. 10, and the optical powers of the far-field and near-field test points in the diagram are determined to meet the design requirement, and then the lens is evaluated to be qualified.
In a specific embodiment of the present application, the evaluation method of the double-sided progressive addition lens is used to evaluate a lens having an outer surface (i.e., a lens front surface) with a radius of curvature of 228mm and an inner surface (i.e., a lens rear surface) with a progressive surface, and in this embodiment, a distance from the pupil center to the rear surface of the lens in the case of wearing glasses is set to 27mm and a pupil circumference radius of 2mm.
In this embodiment, fig. 7 is an astigmatism distribution diagram obtained by simulating the lens using a conventional surface shape method, and fig. 8 is an astigmatism distribution diagram obtained by simulating the lens evaluation method using ray tracing provided by the present application. FIG. 9 is a graph of the power profile obtained by simulating the lens using a conventional surface shape method; FIG. 10 is a graph of power distribution obtained by simulation using the method for evaluating lenses using ray tracing provided by the present application. From fig. 7 to fig. 10, it can be seen that the simulation result based on the ray trace is similar to the simulation result obtained by the surface shape method, but has obvious differences: the application simulates a plurality of light ray starting points at the pupil circumference position and is closer to the actual condition of an object observed by eyes, so that the obtained astigmatism distribution can theoretically reflect the real visual effect of a user when using the lens.
In another embodiment of the present application, a method for designing a dual-sided progressive addition lens is provided, where the evaluation method described in any of the above embodiments is used to obtain an astigmatism distribution and an average power distribution of the lens; and adjusting design parameters of the lens according to the astigmatism distribution and/or the average focal power distribution until the astigmatism distribution of the lens meets the preset standard.
The lens evaluation method provided by the application is applied to the lens design process, can directly evaluate the astigmatism and focal power conditions of each optical tracking position of the lens, is simple, can be fed back to the optimal design according to the evaluation result, can shorten the design period of the lens, and is convenient for industrial popularization and application.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing is merely illustrative of the embodiments of this application and it will be appreciated by those skilled in the art that variations and modifications may be made without departing from the principles of the application, and it is intended to cover all modifications and variations as fall within the scope of the application.
Claims (10)
1. A method for evaluating a double-sided progressive addition lens, comprising the steps of:
determining the mirror structures of the front surface and the rear surface of the lens to be analyzed and the refractive index of the material of the lens to be analyzed;
providing a plurality of discrete features on the rear surface of the lensSample point P bi Wherein i is more than or equal to 1 and less than or equal to j, and j is the integer number of sample points;
determining the center position of the pupil according to the preset glasses relationship for wearing glasses; determining the pupil circumference according to the preset pupil diameter;
taking n pairs of light starting points on the circumference of the pupil, wherein each pair of light starting points is symmetrical relative to the center of the pupil, and n is the integer number of the pairs of light starting points;
for each sample point P bi Its astigmatism is determined by:
to the sample point P in parallel with the pupil center bi Determining two rays from a first pair of ray origins to the rear surface of the lens and ray tracing to obtain their respective intersection points P with the front surface of the lens fi-1 And P fi-2 And an intersection point P fi-1 The exit vector s1 at the intersection point P fi-2 An exit vector s2 at;
obtaining the intersection point P of two rays of the outgoing vectors s1, s2 cross-i1 Obtaining the intersection point P cross-i1 To the sample point P bi And taking the reciprocal of the distance as the focal power of the first pair of light sources
Obtaining the same sample point P bi The focal power of the tangent plane corresponding to the starting point of other light raysTo->
Determining the same sample point P bi Maximum and minimum values in the corresponding individual section powers and taking the difference as the sample point P bi Corresponding astigmatism Δx' bi ；
And obtaining an astigmatism value corresponding to each sample point, simulating the astigmatism distribution of the lens, and taking the astigmatism distribution as a basis for evaluating the lens.
2. The method of evaluating a double-sided progressive addition lens according to claim 1, wherein a contour line of a preset astigmatism threshold is determined in the astigmatism distribution;
estimating the area of the region within the contour line of the preset astigmatism threshold;
and if the area of the area within the high lines is smaller than a preset area threshold value, evaluating that the lens is unqualified.
3. The method for evaluating a double-sided progressive addition lens according to claim 1, wherein the intersection point P of two rays of the outgoing vectors s1, s2 is calculated by the following formula cross-i1 ：
Normal＝s1×s2，
Normal_1＝s1×Normal，
Normal_2＝s2×Normal，
P f-3 ＝P f-2 -P f-1 ，
P cross-i1 ＝P f-1 +s1·(P f-3 ·Normal_2)/(s1·Normal_2)，
Wherein s1 is the emergent vector of the first emergent ray from the front surface of the lens, s2 is the emergent vector of the second emergent ray from the front surface of the lens, normal, normal_1, normal_2 are intermediate calculated variables, P fi-1 Representing the intersection point of the first emergent ray and the front surface of the lens, P fi-2 Representing the intersection point of the second emergent ray and the front surface of the lens, P fi-3 Representing the intersection point P f-2 To the intersection point P f-1 Distance, P cross-i1 The intersection of the two rays of the emission vectors s1, s2 is shown.
4. The method for evaluating a double-sided progressive addition lens according to claim 1, wherein the intersection point P of two rays of light from a first ray origin to the rear surface of the lens and the front surface of the lens is obtained by ray tracing by fi-1 And P fi-2 ：
To the sample point P by the pupil center bi And making a first light ray and a second light ray parallel to the virtual light ray, wherein the first light ray and the second light ray respectively pass through a first light ray starting point;
determining the intersection point P of the first light ray and the rear surface according to the mirror surface structure of the rear surface of the lens bi-1 And the intersection point P bi-1 Normal line ofAnd determining an intersection point P of the second light ray with the rear surface bi-2 And the intersection point P bi-2 Normal line of the department->Determining the refractive ray direction of said first ray after entering said lens>And the direction of the refracted ray of the second ray after entering the lens +.>
Determining an intersection point P in combination with the mirror structure of the front surface of the lens bi-1 Direction of refracted rayIntersection point P of the ray of (C) with the front surface fi-1 And determining the intersection point P bi-2 Refractive ray direction->Intersection point P of the ray of (C) with the front surface fi-2 。
5. The method of evaluating a double-sided progressive addition lens of claim 4, wherein the first light entering is calculated according to the following formulaRefractive ray direction behind the lens
Wherein (1)>For the direction of the refracted ray after the first ray enters the lens, I1 is the refractive index of the material of the lens, < >>For the direction of the first light passing through the start of one of the light rays,/->Is the intersection point P bi-1 Normal vector is positioned;
and calculating the direction of the refracted ray after the second ray enters the lens according to the following formula
Wherein (1)>For the direction of the refracted ray after the second ray enters the lens, I1 is the refractive index of the material of the lens,For the direction of the second light passing through the start of another light>Is the intersection point P bi-2 Normal vector.
6. The method for evaluating a double-sided progressive addition lens according to claim 4, wherein the intersection point P is determined by fi-1 The exit vector s1 at the intersection point P fi-2 An exit vector s2 at;
determining an intersection point P with the front surface of the lens according to the mirror structure of the front surface fi-1 Normal line ofDetermining an intersection point P with the front surface fi-2 Normal line of the department->
Determining the medium refractive index I2 of the environment in which the lens is positioned, and calculating the intersection point P by the following formula fi-1 Exit vector s1 at:
wherein (1)>s1 is the intersection point P fi-1 The emergent vector at the position, I2 is the medium refractive index of the environment where the lens is located, +.>Is the refractive ray direction after the first ray enters the lens, +.>Is the intersection point P fi-1 Normal vector is positioned;
the intersection point P is calculated by the following formula fi-2 Exit vector s2 at:
wherein (1)>s2 is the intersection point P fi-2 The emergent vector at the position, I2 is the medium refractive index of the environment where the lens is located, +.>For the direction of the refracted ray after the second ray enters the lens,Is the intersection point P fi-2 Normal vector.
7. The method for evaluating a double-sided progressive addition lens according to claim 1, wherein the same sample point P is obtained bi The focal power of the tangent plane of each corresponding light ray starting pointTo->Thereafter, an average value of the tangential power is calculated as the sample point P bi A corresponding average optical power;
and obtaining the average focal power corresponding to each sample point, simulating the average focal power distribution of the lens, and taking the average focal power distribution as the basis for auxiliary evaluation of the lens.
8. The method of evaluating a dual-sided progressive addition lens of claim 7, wherein an average power value at a preset location in the average power profile is determined, the preset location comprising a distance zone and a near zone, and the lens is evaluated as being acceptable if the average power of the near zone is 0 and the average power of the distance zone meets a design target power value.
9. The evaluation method of a double-sided progressive addition lens according to any one of claims 1 to 8, characterized in that a point on an optical axis of the lens rear side, which is a predetermined lens eye distance from a center of the lens rear surface, is taken as a pupil center position;
determining a plane in which the pupil circumference is located in a direction perpendicular to the optical axis;
the pairs of light starting points on the circumference of the pupil are more than six pairs, and more than 12 light starting points are distributed on the circumference of the pupil at equal intervals.
10. A method of designing a double-sided progressive addition lens, characterized in that the astigmatism distribution of the lens is obtained by the evaluation method according to any one of claims 1 to 9;
and adjusting design parameters of the lens according to the astigmatism distribution until the astigmatism distribution of the lens meets a preset standard.
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| CN118654584A (en) * | 2024-08-15 | 2024-09-17 | 恒迈光学精密机械(杭州)有限公司 | A method for optical equal thickness testing of free-form surface transparent parts |
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| CN106526890A (en) * | 2016-12-19 | 2017-03-22 | 苏州苏大明世光学股份有限公司 | Progressive multi-focal lens customized for glasses wearer and preparation method of progressive multi-focal lens |
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| CN1274860A (en) * | 1999-05-20 | 2000-11-29 | 庄臣及庄臣视力产品有限公司 | Method for manufacture of graduated supplementary lens |
| WO2008089999A1 (en) * | 2007-01-25 | 2008-07-31 | Rodenstock Gmbh | Method for optimising a spectacle lens |
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