CN102419476B - Optimization method for reducing astigmatism of progressive additional lens - Google Patents

Abstract

The invention discloses a method for reducing the astigmatism of a progressive additional lens, and provides an overall astigmatism optimization method. The method comprises the following step of: adding initial rise distribution data to new rise distribution data of a freedom surface to obtain lens surface shape rise distribution data subjected to astigmatism optimization. After an initial progressive additional lens is optimized by the method provided by the invention, the maximum astigmatism of the lens is reduced by 14.3 percent. In the method, according to a curvature definition in differential geometry, each point is added with a corresponding freedom surface which is related to the minimum curvature and consists of micro cylindrical surfaces so as to reduce the astigmatism of each point, and the direction of each micro cylindrical surface is consistent with the minimum curvature direction of the point; therefore, by the method, the maximum astigmatism of the surface of the lens can be effectively reduced, the distinct range of a vision far zone is enlarged, and the refraction capacity of a user in an effective vision zone is improved.

Description

A kind of optimization method that reduces astigmatism of progressive additional lens

Technical field

The present invention relates to a kind of progressive multi-focus lens, particularly a kind of disposal route that reduces astigmatism of progressive additional lens.

Background technology

Progressive multi-focus lens can satisfy simultaneously look far away with look near demand, avoided again two light microscopics etc. look far away when looking nearly conversion the defective such as fracture, the application of present progressive multi-focus lens is day by day extensive.Referring to accompanying drawing 1, the progressive multi-focus lens surface is divided into looks far field 1, intermediate transition zone 2, near reading range 3 and astigmatism district 4.

Before the present invention made, United States Patent (USP) (US 4861153) disclosed a kind of preparation method of eye lens.Often there is larger astigmatism in this method in peripheral spread area, and excessive astigmatism can hinder eyeglass wearer's euphorosia degree on the eyeglass.If change the initial designs parameter, can make again the area optical character variation that has met the demands on the eyeglass.Therefore, on the basis that obtains the distribution of lens surface rise, how eyeglass is optimized, can guarantee that initial designs parameter and lens optical character are constant, can reduce the lens periphery astigmatism again, make astigmatism distribution can more become to satisfying wearer's requirement, tool is of great significance.

Chinese patent (201010548849.4) discloses a kind of optimization method of astigmatism of progressive additional lens, the method is: according to prior art on the basis of the initial rise distributed data that obtains progressive multi-focus lens face shape, select the upper astigmatism value of eyeglass face shape to be made as astigmatism greater than 80% the zone that adds light quantity or the part in the described zone and optimize the zone, the method of its astigmatism optimization process is: initial rise data that should the zone sphere rise that deducts take the mean value of this regional focal power as focal power that distributes distributes, obtaining the poor data of two curved surface rises distributes, it is adopted the mean curvature flow smoothing processing, resulting result adds this sphere rise and distributes, and obtains the eyeglass face shape rise distributed data after astigmatism is optimized.Optimization Steps by this invention is processed, and can effectively reduce the maximum astigmatism on progressive multi-focus lens surface, and the refractive power in its effective visible sensation district is substantially constant.Yet the method is that eyeglass is carried out local optimum, whole eyeglass is not all optimized, and can not make astigmatism distribution reach ideal state, does not also well improve available field of visual, therefore still has many defectives.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of optimization method that can effectively reduce astigmatism of progressive additional lens, make astigmatism distribution can more become to satisfying wearer's demand, and the refractive power in Effective Raise effective visible sensation district, and cost is lower, is convenient to industry and applies.

For solving the problems of the technologies described above, the invention provides following technical scheme and be: a kind of optimization method that reduces astigmatism of progressive additional lens, as follows operation:

(1) according to designing requirement and the lens parameters of eyeglass to be processed, obtains the initial rise distributed data z before eyeglass face shape is optimized ₀(x, y);

(2) it is as follows to derive on the eyeglass curvature formulations of each point on all directions, and wherein orientation angle is θ:

$k(x,y,\mathrm{\&theta;})=\frac{\frac{{\&PartialD;}^{2}z}{{\&PartialD;x}^2}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000124443430000011.png,HDA0000124443430000061.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&theta;}+2\frac{{\&PartialD;}^{2}z}{\&PartialD;x\&PartialD;y}\sin \mathrm{\&theta;}\cos \mathrm{\&theta;}+\frac{{\&PartialD;}^{2}z}{\&PartialD;y^2}{\sin }^2\mathrm{\&theta;}}{{[1+{(\frac{\&PartialD;z}{\&PartialD;x}\cos \mathrm{\&theta;}+\frac{\&PartialD;z}{\&PartialD;y}\sin \mathrm{\&theta;})}^2]}^{\frac{3}{2}}};$ Utilize this formula according to initial rise distributed data z before optimizing ₀Each point maximum curvature k on the eyeglass before (x, y) calculates and optimize _MaxThe direction θ of (x, y) and maximum curvature _Max(x, y); And calculate optimize before each point minimum curvature k on the eyeglass _MinThe direction θ of (x, y) and minimum curvature _Min(x, y);

(3) the average principal curvatures of each point is on the front eyeglass of optimization:

The principal curvatures of each point is poor on the eyeglass before optimizing is: δ ₀(x, y)=k _Max(x, y)-k _Min(x, y)

(4) the rise distributed data z of a new free form surface of calculating _t(x, y):

New free form surface is comprised of the small cylinder of each different curvature, and the curvature of each small cylinder is:

C(x,y)＝δ ₀(x,y)/M；

In the formula, δ ₀(x, y) is poor for the principal curvatures of each point before optimizing, and M is the constant of 20-35;

New free form surface rise is distributed as: $z_t(x,y)=\frac{C(x,y){(x\cos {\mathrm{\&theta;}}_t-y\sin {\mathrm{\&theta;}}_t)}^2}{1+\sqrt{1-C^2(x,y){(x,y)(x\cos {\mathrm{\&theta;}}_t-y\sin {\mathrm{\&theta;}}_t)}^2}};$

In the formula, θ _iGet the minimum curvature direction θ of the each point that step (2) tries to achieve _Min(x, y);

(5) eyeglass face shape is optimized front initial rise distributed data z ₀(x, y) and new free form surface rise distributed data z _t(x, y) addition obtains the eyeglass face shape rise distributed data z after astigmatism is optimized ₁(x, y); According to z ₁(x, y) processes the progressive multi-focus lens that reduces astigmatism.

As a kind of preferred version that reduces the optimization method of astigmatism of progressive additional lens of the present invention, wherein: the each point maximum curvature k in the described step (2) _MaxThe direction θ of (x, y) and maximum curvature _Max(x, y) and each point minimum curvature k _MinThe direction θ of (x, y) and minimum curvature _Min(x, y) calculates as follows: θ gets a value every 3 °-18 °, tries to achieve each corresponding k (x, y, θ) value according to the computing formula in the step (2), and relatively obtains each point maximum curvature k _Max(x, y) and minimum curvature k _Min(x, y), and the direction θ of corresponding maximum curvature _MaxThe direction θ of (x, y) and minimum curvature _Min(x, y).

As a kind of preferred version that reduces the optimization method of astigmatism of progressive additional lens of the present invention, wherein: in the described step (4), the poor δ of principal curvatures on the eyeglass ₀(x, y) makes δ less than the point of 0.25/n-1/1000 ₀(x, y)=0, n is the eyeglass refractive index in the formula.

As a kind of preferred version that reduces the optimization method of astigmatism of progressive additional lens of the present invention, wherein: the M value in the described step (4) gets 25.

As a kind of preferred version that reduces the optimization method of astigmatism of progressive additional lens of the present invention, wherein: θ gets a value every 7.5 ° in the described step (2).

Compared with prior art, after initial progressive multi-focus lens was processed through technical scheme of the present invention, its obvious advantage was that the maximum astigmatism of eyeglass has reduced 14.3%, obviously increases depending on effective viewing area, far field.Because the method is that whole eyeglass is all optimized, so effect of optimization is more even.Simultaneously, the method is the definition according to the infinitesimal geometry mean curvature, for reducing the each point astigmatism, adds the free form surface that a small cylinder relevant with this minimum curvature size forms at each point, and the direction of each small cylinder is consistent with the minimum curvature direction of this point.Therefore, after step process of the present invention, not only reduced astigmatism, and improved available field of visual, the important optical parametric of eyeglass is constant.

Description of drawings

Fig. 1 is the subregion synoptic diagram of progressive multi-focus lens; Among the figure, 1, look the far field; 2, intermediate transition zone; 3, near reading range; 4, astigmatism district.

The flow chart of steps that the astigmatism of a kind of progressive multi-focus lens that Fig. 2 provides for the embodiment of the invention one is optimized.

Fig. 3 for the progressive multi-focus lens that obtains by prior art etc. the focal power line drawing.

Fig. 4 for the astigmatism optimization method that provides through the embodiment of the invention one progressive multi-focus lens after processing etc. the focal power line drawing.

Fig. 5 waits the astigmatism line drawing for the progressive multi-focus lens that obtains by prior art.

Fig. 6 waits the astigmatism line drawing for the astigmatism optimization method that provides through the embodiment of the invention one progressive multi-focus lens after processing.

Fig. 7 processes front and back eyeglass surface optics nature parameters contrast for the astigmatism optimization method that provides through the embodiment of the invention one.

Fig. 8 for the astigmatism optimization method that provides through the embodiment of the invention two progressive multi-focus lens after processing etc. the focal power line drawing.

Fig. 9 waits the astigmatism line drawing for the astigmatism optimization method that provides through the embodiment of the invention two progressive multi-focus lens after processing.

Figure 10 for the astigmatism optimization method that provides through the embodiment of the invention three progressive multi-focus lens after processing etc. the focal power line drawing.

Figure 11 waits the astigmatism line drawing for the astigmatism optimization method that provides through the embodiment of the invention three progressive multi-focus lens after processing.

Embodiment

The invention will be further described below in conjunction with accompanying drawing and embodiment.

Embodiment one:

In the present embodiment, the designing requirement parameter of eyeglass to be processed is: looking the far point eyeglass number of degrees is 0 diopter, depending on far away and look to add light quantity between the near point be 1.8 diopters, eyeglass passage length h=14 millimeter.

The lens parameters of eyeglass to be processed is: diameter 66mm, refractive index 1.523.

Referring to accompanying drawing 1, it is the subregion synoptic diagram of progressive multi-focus lens, and lens surface is divided into looks far field 1, intermediate transition zone 2, near reading range 3 and astigmatism district 4.

Referring to accompanying drawing 2, it is the flow chart of steps that a kind of astigmatism to progressive multi-focus lens that present embodiment provides is optimized processing, and concrete step is:

1, initial eyeglass face shape rise distributes

In the present embodiment, first by US Patent No. 4861153 disclosed methods, the initial rise distributed data z of the progressive multi-focus lens face shape before being optimized ₀(x, y).

2, maximum curvature and maximum curvature direction, minimum curvature and the minimum curvature direction of each point on the front eyeglass of calculation optimization

Press disclosed method in the document " infinitesimal geometry ", the curvature formulations of plane curve is:

$k_r=\frac{\frac{d^{2}y}{{\mathrm{dx}}^2}}{{[1+{\left(\frac{\mathrm{dy}}{\mathrm{dx}}\right)}^2]}^{\frac{3}{2}}};$

The known differential equation again $\frac{\mathrm{dz}}{{\mathrm{dr}}_{\mathrm{\&theta;}}}=\frac{\mathrm{dz}}{\mathrm{dx}}\cos \mathrm{\&theta;}+\frac{\mathrm{dz}}{\mathrm{dy}}\sin \mathrm{\&theta;};$

It is as follows to derive the curvature formulations of each point on all directions, and wherein orientation angle is θ:

$k(x,y,\mathrm{\&theta;})=\frac{\frac{{\&PartialD;}^{2}z}{{\&PartialD;x}^2}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000124443430000011.png,HDA0000124443430000061.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&theta;}+2\frac{{\&PartialD;}^{2}z}{\&PartialD;x\&PartialD;y}\sin \mathrm{\&theta;}\cos \mathrm{\&theta;}+\frac{{\&PartialD;}^{2}z}{\&PartialD;y^2}{\sin }^2\mathrm{\&theta;}}{{[1+{(\frac{\&PartialD;z}{\&PartialD;x}\cos \mathrm{\&theta;}+\frac{\&PartialD;z}{\&PartialD;y}\sin \mathrm{\&theta;})}^2]}^{\frac{3}{2}}};$

θ gets a value every 7.5 °, utilizes this computing formula according to initial rise distributed data z before optimizing ₀(x, y) tries to achieve each corresponding k (x, y, θ) value, and relatively obtains each point maximum curvature k _Max(x, y) and minimum curvature k _Min(x, y), and the direction θ of corresponding maximum curvature _MaxThe direction θ of (x, y) and minimum curvature _Min(x, y).

3, calculate eyeglass optical power profile and astigmatism distribution

The average principal curvatures of optimizing each point on the front eyeglass is:

The principal curvatures of each point is poor on the eyeglass before optimizing is: δ ₀(x, y)=k _Max(x, y) k _Min(x, y; Average principal curvatures μ according to each point on the eyeglass before optimizing ₀The focal power Φ of each point on this eyeglass before (x, y) calculation optimization ₀(x, y)=1000 (n-1) μ ₀(x, y) diopter; The poor δ of principal curvatures according to each point on the eyeglass before optimizing ₀The astigmatism ast of each point on this eyeglass before (x, y) calculation optimization ₀(x, y)=1000 (n-1) δ ₀(x, y) diopter, wherein n is the Refractive Index of Material of eyeglass, 1 diopter=1m ^-1

4, calculate the rise distributed data z of a new free form surface _t(x, y)

New free form surface is comprised of the small cylinder of each different curvature, and the curvature of each small cylinder is:

C(x,y)＝δ ₀(x,y)/M；

In the formula, δ ₀(x, y) is poor for the principal curvatures of each point before optimizing, and M gets 25;

According to Formula of Coordinate System Transformation:

$\left\{\begin{array}{c}{x}^{\&prime;}=x\cos {\mathrm{\&theta;}}_t-y\sin {\mathrm{\&theta;}}_t\\ y^{\&prime;}=x\cos {\mathrm{\&theta;}}_t+y\sin {\mathrm{\&theta;}}_t\end{array}\right.$ Calculate x', y',

New free form surface rise is distributed as $z_t(x,y)=\frac{C(x,y)x^{\&prime;}}{1+\sqrt{C^2(x,y)x^{\&prime;2}}}=\frac{C(x,y){(x\cos {\mathrm{\&theta;}}_t-y\sin {\mathrm{\&theta;}}_t)}^2}{1+\sqrt{1-C^2(x,y){(x\cos {\mathrm{\&theta;}}_t-y\sin {\mathrm{\&theta;}}_t)}^2}};$

In the formula, θ _iGet the minimum curvature direction θ of the each point that step (2) tries to achieve _Min(x, y);

5, eyeglass face shape rise distribution optimization is processed and machining eyeglass

Eyeglass face shape is optimized front initial rise distributed data z ₀(x, y) and new free form surface rise distributed data z _t(x, y) addition obtains the eyeglass face shape rise distributed data z after astigmatism is optimized ₁(x, y); According to z ₁(x, y) machining lens obtains a kind of progressive multi-focus lens that reduces astigmatism.

Process eyeglass face shape rise data rise data distribution z after the astigmatism that obtains is optimized by the technical scheme of present embodiment one ₁(x, y) calculates the average principal curvatures distribution u of eyeglass by the method for step 2 and step 3 ₁(x, y) and principal curvatures difference cloth δ ₁(x, y), wherein z ₀(x, y) is by z ₁(x, y) replaces, and obtains thus the optical power profile Φ of eyeglass ₁(x, y) and astigmatism distribution ast ₁(x, y).After tested, after eyeglass was optimized, maximum astigmatism had reduced 14.3%, obviously enlarge depending on the far field definition range, Effective Raise the refractive power of corresponding available field of visual.

Referring to accompanying drawing 3, it for the progressive multi-focus lens that obtains by prior art etc. the focal power line drawing; Referring to accompanying drawing 4, the progressive multi-focus lens after the astigmatism optimization method that it provides for the embodiment of the invention one is processed etc. the focal power line drawing.Comparison diagram 3 and Fig. 4 can find out that after the employing technical solution of the present invention, focal power is that the 0 dioptric outline line that waits is more smooth, shows that looking the far field definition range obviously enlarges, and has improved wearer's available field of visual.

Referring to accompanying drawing 5, it waits the astigmatism line drawing for the progressive multi-focus lens that obtains by prior art; Referring to accompanying drawing 6, it waits the astigmatism line drawing for the astigmatism optimization method that provides through the embodiment of the invention one progressive multi-focus lens after processing; Comparison diagram 5 and Fig. 6 can see that after the employing technical solution of the present invention, the maximum astigmatism in astigmatism district, lens surface left side is reduced to 2 diopters from 2.25 diopters, makes maximum astigmatism value descend 12.5%; The maximum astigmatism in astigmatism district, right side is reduced to 1.75 diopters from 2 diopters, makes maximum astigmatism value descend 14.3%.

Referring to accompanying drawing 7, it processes front and back eyeglass surface optics nature parameters contrast for the astigmatism optimization method that provides through the embodiment of the invention one.Optimize front-and rear-view far field and near reading range focal power and do not change, do not change the important optical parametric of eyeglass; Be that the peak width of 0D has increased 18mm depending on the far field in y=-5mm place focal power, effectively enlarged and looked the far field available field of visual; The isoline that equals 0.25D at x=20mm place astigmatism is to the height of the horizontal central line 3.5mm that descended; Be apparent that most: the peak width that equals 2D at x=-10mm place astigmatism has reduced 3mm; The peak width that equals 1.75D at x=10mm place astigmatism has reduced 13mm, has obviously improved astigmatism distribution.These variations make the wearer of progressive multi-focus lens feel more comfortable, are more prone to adapt to progressive multi-focus lens.

Embodiment two

Implementation step such as embodiment one, wherein θ gets 3 °, and M gets 35.

Referring to accompanying drawing 8, the progressive multi-focus lens after the astigmatism optimization method that it provides for the embodiment of the invention two is processed etc. the focal power line drawing.Comparison diagram 3 and Fig. 8 can find out that after the technical scheme that the employing embodiment of the invention two provides, focal power is that the 0 dioptric outline line that waits is more smooth, shows that looking the far field definition range obviously enlarges, and has improved wearer's available field of visual.

Referring to accompanying drawing 9, the line drawing such as astigmatism such as grade of the progressive multi-focus lens after the astigmatism optimization method that it provides for the embodiment of the invention two is processed.Comparison diagram 5 and Fig. 9 can see that after the technical scheme that employing embodiment two provides, the maximum astigmatism in astigmatism district, lens surface left side is reduced to 2 diopters from 2.25 diopters, makes maximum astigmatism value descend 12.5%; Astigmatism district, right side is that 2 dioptric zones are reduced into a very speckle.Comparison diagram 6 and Fig. 9 can see that the lens surface astigmatism distribution after the astigmatism optimization method that embodiment one provides is processed is slightly better than embodiment two effects.

Embodiment three

Implementation step such as embodiment one, wherein θ gets 18 °, and M gets 20.

Referring to accompanying drawing 10, the progressive multi-focus lens after the astigmatism optimization method that it provides for the embodiment of the invention three is processed etc. the focal power line drawing.Comparison diagram 3 and Figure 10 can find out that after the technical scheme that the employing embodiment of the invention three provides, focal power is that the 0 dioptric outline line that waits is more smooth, shows that looking the far field definition range obviously enlarges, and has improved wearer's available field of visual.

Referring to accompanying drawing 11, the line drawing such as astigmatism such as grade of the progressive multi-focus lens after the astigmatism optimization method that it provides for the embodiment of the invention three is processed.Comparison diagram 5 and Figure 11 can see that after the technical scheme that employing embodiment three provides, the maximum astigmatism in astigmatism district, lens surface left side is reduced to 2 diopters from 2.25 diopters, makes maximum astigmatism value descend 12.5%; Astigmatism district, right side is that 2 dioptric zones are reduced into a very speckle.Comparison diagram 6 and Figure 11 can see that the lens surface astigmatism distribution of implementing after an astigmatism optimization method that provides is processed is slightly better than embodiment three effects.

The present invention is take the progressive multi-focus lens design and optimization as target, obtain in prior art on the basis of initial rise distributed data of progressive multi-focus lens face shape, overall astigmatism optimization method is proposed, be about to the rise distributed data addition of the new free form surface of initial rise distributed data and, obtain the eyeglass face shape rise distributed data after astigmatism is optimized.Initial progressive multi-focus lens is through behind the Optimization Steps provided by the invention, and the maximum astigmatism of eyeglass has reduced 14.3%.The method is the definition according to the infinitesimal geometry mean curvature, for reducing the each point astigmatism, add the free form surface that a small cylinder relevant with this minimum curvature size forms at each point, the direction of each small cylinder is consistent with the minimum curvature direction of this point, so Optimization Steps of the present invention can effectively reduce the maximum astigmatism of lens surface, and expansion is looked the far field definition range, raising wearer's available field of visual.

It should be noted that, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although with reference to preferred embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (5)

1. optimization method that reduces astigmatism of progressive additional lens is characterized in that carrying out the operation of following steps:

(1) according to designing requirement and the lens parameters of eyeglass to be processed, obtains the initial rise distributed data z before eyeglass face shape is optimized ₀(x, y);

(2) it is as follows to derive on the eyeglass curvature formulations of each point on all directions, and wherein orientation angle is θ:

$k(x,y,\mathrm{\&theta;})=\frac{\frac{{\&PartialD;}^{2}z}{{\&PartialD;x}^2}{\cos }^2\mathrm{\&theta;}+2\frac{{\&PartialD;}^{2}z}{\&PartialD;x\&PartialD;y}\sin \mathrm{\&theta;}\cos \mathrm{\&theta;}+\frac{{\&PartialD;}^{2}z}{\&PartialD;y^2}{\sin }^2\mathrm{\&theta;}}{{[1+{(\frac{\&PartialD;z}{\&PartialD;x}\cos \mathrm{\&theta;}+\frac{\&PartialD;z}{\&PartialD;y}\sin \mathrm{\&theta;})}^2]}^{\frac{3}{2}}};$ Utilize this formula according to initial rise distributed data z before optimizing ₀Each point maximum curvature k on the eyeglass before (x, y) calculates and optimize _MaxThe direction θ of (x, y) and maximum curvature _Max(x, y); And calculate optimize before each point minimum curvature k on the eyeglass _MinThe direction θ min (x, y) of (x, y) and minimum curvature;

(3) the average principal curvatures of each point is on the front eyeglass of optimization:

The principal curvatures of each point is poor on the eyeglass before optimizing is: δ ₀(x, y)=k _Max(x, y)-k _Min(x, y);

(4) the rise distributed data z of a new free form surface of calculating _t(x, y):

New free form surface is comprised of the small cylinder of each different curvature, and the curvature of each small cylinder is:

C(x,y)＝δ ₀(x,y)/M；

In the formula, δ ₀(x, y) is poor for the principal curvatures of each point before optimizing, and M is the constant of 20-35; New free form surface rise is distributed as: $z_t(x,y)=\frac{C(x,y){(x\cos {\mathrm{\&theta;}}_t-y\sin {\mathrm{\&theta;}}_t)}^2}{1+\sqrt{1-C^2(x,y){(x\cos {\mathrm{\&theta;}}_t-y\sin {\mathrm{\&theta;}}_t)}^2}};$

In the formula, θ _tGet the minimum curvature direction θ of the each point that step (2) tries to achieve _Min(x, y);

(5) eyeglass face shape is optimized front initial rise distributed data z ₀(x, y) and new free form surface rise distributed data z _t(x, y) addition obtains the eyeglass face shape rise distributed data z after astigmatism is optimized ₁(x, y); By z ₁(x, y) processes the progressive multi-focus lens that reduces astigmatism.

2. the optimization method that reduces astigmatism of progressive additional lens according to claim 1 is characterized in that: the each point maximum curvature k in the described step (2) _MaxThe direction θ of (x, y) and maximum curvature _Max(x, y) and each point minimum curvature k _MinThe direction θ of (x, y) and minimum curvature _Min(x, y) calculates as follows: θ gets a value every 3 °-18 °, tries to achieve each corresponding k (x, y, θ) value according to the computing formula in the step (2), and relatively obtains each point maximum curvature k _Max(x, y) and minimum curvature k _Min(x, y), and the direction θ of corresponding maximum curvature _MaxThe direction θ of (x, y) and minimum curvature _Min(x, y).

3. the optimization method that reduces astigmatism of progressive additional lens according to claim 1 is characterized in that: in the described step (4), for the poor δ of principal curvatures on the eyeglass ₀(x, y) makes δ less than the point of 0.25/n-1/1000 ₀(x, y)=0, n is the eyeglass refractive index in the formula.

4. the optimization method that reduces astigmatism of progressive additional lens according to claim 1, it is characterized in that: the M value in the described step (4) gets 25.

5. the optimization method that reduces astigmatism of progressive additional lens according to claim 2 is characterized in that: θ gets a value every 7.5 ° in the described step (2).

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