CN1779506A - Farsighted lens - Google Patents

Abstract

A long sight glasses lens consists of the first surface of nonspherical surface and the second surface of scrobicula surface. The form of two said surface is seceded by nonspherical formula as Z= Cvr2/1+(1-Pcv2r2) +Br4 + Cr6 + Dr8 + Er10 where Z-lens surface depth; Cv - central curvity of nonspherical surface; r - vertical height from any point on lens surface to lens surface center; p - secondary curve constant value; B,C,D and E - nonspherical height second item coefficient.

Description

Farsighted lens

[technical field]

The present invention is about a kind of Farsighted lens, especially about a kind of Farsighted lens that adopts aspheric surface design.

[background technology]

For myopia correction and long sight, lens can be divided into two kinds, and a kind of is concavees lens, and a kind of is convex lens.

The lens thickness of Farsighted lens, weight and light transmission thereof become the Consideration that wearer selects eyeglass.Thicker Farsighted lens, can increase eyeglass weight, also can reduce eyeglass transmittance, affects eyeglass sharpness, and thicker eyeglass also can affect wearer's appearance simultaneously.Heavier Farsighted lens, can press the bridge of the nose, increases eye sense of fatigue.

Tool quality is light, thin thickness and minute surface levelling can lens, also require to there is less aberration simultaneously, and performance preferably lens depend on to a great extent method for designing spectacle lenses.

Farsighted lens generally includes two refractive surfaces, and in traditional Farsighted lens design, two refractive surfaces all adopt sphere, are convenient to processing, but along with the eyeglass number of degrees increase, eyeglass thickening, affects attractive in appearance.For addressing this problem, people start to design aspheric surface Farsighted lens, in prior art, as be disclosed in No. 02138569th, the China's Mainland patented claim on April 23rd, 2003, disclosed another kind of aspheric surface Farsighted lens design, wherein, in this Farsighted lens, at least one refractive surface is aspheric surface, and this aspheric surface computing formula adopts following form:

$z=\frac{c_v{r}^2}{1+\sqrt{1-c_v^2{r}^2}}+a_1{r}^4+a_2{r}^6+a_3{r}^8+a_4{r}^{10}+a_5{r}^{12}$

In this aspheric surface formula, although introduce even item, design aspherical lens, but, in its formula, r gets power 12 times, asphericity coefficient adopts 5 values, make its asphericity coefficient that places one's entire reliance upon adjust aberration, cannot obtain the good lens design of overall performance, in addition, though the aspherical lens thickness being calculated by this formula is than same specification spheric glass reduced thickness, in its four embodiment that provide, lens thickness only, than between the little 0.5-0.8mm of former sphere lens thickness, can not meet the demand of people to thinner Farsighted lens.

In view of above shortcoming, be necessary to provide a kind of lightweight, thin thickness and the smooth spectacles for long sight of minute surface.

[summary of the invention]

The object of the present invention is to provide a kind of lightweight, thin thickness and the smooth Farsighted lens of minute surface.

A Farsighted lens, comprises a first surface and a second surface, and wherein first surface is aspheric surface, and second surface is scrobicula face, and its shape is determined by aspheric surface formula:

$\frac{c_r{r}^2}{1+\sqrt{1-{\mathrm{Pc}}_v^2{r}^2}}+{\mathrm{Br}}^4+{\mathrm{Cr}}^6+{\mathrm{Dr}}^8+{\mathrm{Er}}^{10}$

In formula, z is the minute surface degree of depth, C _vrepresent aspheric surface curvature of centre, $r(r=\sqrt{x^2+y^2})$

Represent that on minute surface, any point is to the vertical height at minute surface center, P is conic constant value, and B, C, D, E represent aspheric surface high-order term coefficient.

Compared with prior art, the design of this aspheric surface Farsighted lens, adopts aspheric surface computing formula, can make the effective attenuate of lens thickness; The aspheric surface formula adopting, by introducing even item, has guaranteed the symmetry of lens surface, is conducive to manufacture processing; Introduce conic constant, by this conic constant and asphericity coefficient, come together to adjust lens performance, the Farsighted lens of design is compared with same specification sphere Farsighted lens, reduce thickness and alleviated weight, eyeglass is compared more smooth with spheric glass, met the demand of lens design.

[embodiment]

Now the invention will be further described in conjunction with specific embodiments: Farsighted lens of the present invention comprises a first surface and a second surface, and with wearing spectacles, one side is outside eyeglass first surface, and the one side of being close to eyes is eyeglass second surface.Here defining first surface radius-of-curvature is R ₁, second surface radius-of-curvature is R ₂, n is eyeglass material refractive index, t is center of lens thickness, the index of refraction F of first surface ₁=(n-1)/R ₁, the index of refraction F of second surface ₂=(1-n)/R ₂, the number of degrees of Farsighted lens (diopter) are Farsighted lens back focal length gained reciprocal, its formula:

$F_V=\frac{F_1+F_2-\frac{t}{n}{F}_1{F}_2}{1-\frac{t}{n}{F}_1}$

F _vunit is 1/ meter, conventionally with D, represents, general 1D=100 degree, and our usual said Farsighted lens number of degrees, are exactly F _vvalue is multiplied by 100 value.By formula, obtained, Farsighted lens material is certain, so the Farsighted lens number of degrees are by first surface radius of curvature R ₁, R ₂and t value decides.

During design, for making the thickness that this Farsighted lens tool is thinner, need to be designed to applicable edge thickness e.Edge thickness e can not be too little, if too small, easily cracked, if too large, causes the waste of material, gains in weight.Edge thickness e while and center thickness t, first surface radius of curvature R ₁, the second face curvature radius R ₂relevant.During design, by edge thickness desired value, calculate t value, after t value is determined, by adjusting R ₁and R ₂value guarantees that the Farsighted lens number of degrees are constant.R ₁and R ₂change further have influence on the change of e, for keeping e constant, then adjust center thickness t, after adjustment, then be optimized, thereby calculate satisfied asphericity coefficient optimal value.

This Farsighted lens adopts plastic cement material, the density p=1.25g/mm of this plastic cement material ³, wherein at least one surface is aspheric surface, the aspheric surface computing formula that wherein aspheric surface adopts is

$z\frac{c_v{r}^2}{1+\sqrt{1-{\mathrm{Pc}}_v^2{r}^2}}+{\mathrm{Br}}^4+{\mathrm{Cr}}^6+{\mathrm{Dr}}^8+{\mathrm{Er}}^{10}$

Wherein, in formula, z is the minute surface degree of depth, C _vrepresent aspheric surface curvature of centre, $r(r=\sqrt{x^2+y^2})$ Represent that on minute surface, any point is to the vertical height at minute surface center, P is conic constant value, P < 0 in the present embodiment, and B, C, D, E represent aspheric surface high-order term coefficient.

Getting second surface is scrobicula face, and first surface is aspheric surface, and in the design, first surface designs with the aspheric surface of hyperboloid distortion, and wherein conic constant value P gets the value that is less than 0.C in aspheric surface formula _vinverse for first surface radius-of-curvature.First get R ₁, R ₂be a fixed value, by optimizer, determine first surface aspheric surface P, B, C, D, the value of E, in optimizing process, R2 can adjust according to the Farsighted lens number of degrees.

Complete for the first time after optimizing process, calculate t value, the further e that obtains, for making the thick desired value that is approximately in limit, our desired value is decided to be 1mm here, and center thickness t need be deducted to edge thickness increment, constant for guaranteeing the Farsighted lens number of degrees, further adjust second index of refraction, then be optimized, the result t after optimizing for the second time continues to deduct the increment of e.The like, repeatedly, after loop optimization, can obtain edge thickness and become into 1mm.

The first embodiment of Farsighted lens of the present invention: a kind of aspheric surface Farsighted lens, the number of degrees are 1D, and first surface is aspheric surface, and second is scrobicula face, and the parameter list of this aspheric surface Farsighted lens, asks for an interview table 1.

Table 1

Specification	The aspheric surface Farsighted lens of design	The sphere Farsighted lens of same specification
			Diopter:	1.0D
Optic diameter:	72mm
			First surface radius-of-curvature:	213.9041mm	74.5031mm
The second face curvature radius:	335.1565mm	84.2894mm
			Quadric surface constant P:	-6.3927	Nothing
Asphericity coefficient:	B：-8.8665×10 -8 C：8.287×10 -11 D：-2.973×10 -14 E：-1.1087×10 -17	Nothing
			Center thickness:	1.873mm	2.201mm
Edge thickness:	1.001mm	1.000mm
			Axial height:	3.812mm	10.275mm
Oblique fire astigmatism:	0	0
			Index of refraction error:	-0.056D	-0.056D
Distortion:	1.226％	1.260％
			Weight:	7.114g	8.325g

Compare with same specification sphere Farsighted lens, its center thickness reduces 15%, and axial height reduces 63%, weight saving 15%, compares with sphere Farsighted lens, has obviously reduced thickness and the weight of Farsighted lens, Farsighted lens is compared with sphere Farsighted lens simultaneously, more smooth.

The second embodiment of invention Farsighted lens: a kind of aspheric surface Farsighted lens, the number of degrees are 2D, and first surface is aspheric surface, and second is scrobicula face, and the parameter list of this aspheric surface Farsighted lens, asks for an interview table 2.

Table 2

Specification	The aspheric surface Farsighted lens of design	The sphere Farsighted lens of same specification
			Diopter:	2D
Optic diameter:	72mm
			First surface radius-of-curvature:	181.5909mm	66.2660mm
The second face curvature radius:	470.5473mm	83.5023mm
			Quadric surface constant P:	-8.1367	Nothing
Asphericity coefficient:	B：-1.7047×10 -7 C： 1.2603×10 -10 D：-4.7475×10 -14 E： -6.0824×10 -18	Nothing

Center thickness:	2.775mm	3.473mm
			Edge thickness:	1.000mm	1.000mm
Axial height:	4.154mm	11.631mm
			Oblique fire astigmatism:	0	0
Index of refraction error:	-0.115D	-0.114D
			Distortion:	2.335％	2.266％
Weight:	9.276g	11.814g

Compare with same specification sphere Farsighted lens, its center thickness reduces 20%, and axial height reduces 64%, weight saving 21%, compares with sphere Farsighted lens, has obviously reduced thickness and the weight of Farsighted lens, Farsighted lens is compared with sphere Farsighted lens simultaneously, more smooth.

The 3rd embodiment of Farsighted lens of the present invention: a kind of aspheric surface Farsighted lens, the number of degrees are 3D, and first surface is aspheric surface, and second is scrobicula face, and the parameter list of this aspheric surface Farsighted lens, asks for an interview table 3.

Table 3

Specification	The aspheric surface Farsighted lens of design	The sphere Farsighted lens of same specification
			Diopter:	3D
Optic diameter:	72mm
			First surface radius-of-curvature:	158.0317mm	60.2695mm
The second face curvature radius:	791.7613mm	83.5195mm
			Quadric surface constant P:	-8.0105	Nothing
Asphericity coefficient:	B：-2.4955×10 -7 C： 1.3738×10 -10 D： -4.6234×10 -14 E：-4.5764×10 -18	Nothing
			Center thickness:	3.660mm	4.777mm
Edge thickness:	1.001mm	1.000mm
			Axial height:	4.478mm	12.933mm
Oblique fire astigmatism:	0	0
			Index of refraction error:	-0.176D	-0.174D
Distortion:	3.389％	3.170％
			Weight:	11.383g	15.460g

Compare with the sphere Farsighted lens of same specification, its center thickness reduces 23%, and axial height reduces 65%, weight saving 26%, compares with sphere Farsighted lens, has obviously reduced thickness and the weight of Farsighted lens, Farsighted lens is compared with sphere Farsighted lens simultaneously, more smooth.

The 4th embodiment of invention Farsighted lens: a kind of aspheric surface Farsighted lens, the number of degrees are 4D, and first surface is aspheric surface, and second is scrobicula face, and the parameter list of this aspheric surface Farsighted lens, asks for an interview table 4.

Table 4

Specification	The aspheric surface Farsighted lens of design	The sphere Farsighted lens of same specification
			Diopter:	4D
Optic diameter:	72mm
			First surface radius-of-curvature:	132.2325mm	55.0851mm
The second face curvature radius:	1198.686mm	82.5985mm
			Quadric surface constant P:	-5.5079	Nothing
Asphericity coefficient:	B：-3.1912×10 -7 C： 1.2857×10 -10 D： -3.0321×10 -14 E：-9.234×10 -18	Nothing
			Center thickness:	4.567mm	6.134mm
Edge thickness:	1.001mm	1.000mm
			Axial height:	5.107mm	14.391mm
Oblique fire astigmatism:	0	0
			Index of refraction error:	-0.237D	-0.236D
Distortion:	4.371％	3.955％
			Weight:	13.558g	19.359g

Compare with the sphere Farsighted lens of same specification, its center thickness reduces 26%, and axial height reduces 65%, weight saving 30%, compares with sphere Farsighted lens, has obviously reduced thickness and the weight of Farsighted lens, Farsighted lens is compared with sphere Farsighted lens simultaneously, more smooth.

Its oblique fire astigmatism of designed aspheric surface Farsighted lens is 0, and the curvature of field is average index of refraction error, and all, in being less than 0.25 scope, distortion is less than in 4.371% scope, so all can meet the demands.

Claims (7)

1. a Farsighted lens, comprises a first surface and a second surface, it is characterized in that: first surface is aspheric surface, and second surface is scrobicula face, and described aspherical shape is decided by following aspheric surface formula:

$z=\frac{c_v{r}^2}{1+\sqrt{1-P{c}_v^2{r}^2}}+{\mathrm{Br}}^4+{\mathrm{Cr}}^6+{\mathrm{Dr}}^8+{\mathrm{Er}}^{10}$

In formula, z is the minute surface degree of depth, C _vrepresent aspheric surface curvature of centre, r represents that on minute surface, any point is to the vertical height at minute surface center, and P is conic constant value, and B, C, D, E represent aspheric surface high-order term coefficient.

2. Farsighted lens as claimed in claim 1, is characterized in that: P < 0 in described aspheric surface formula.

3. Farsighted lens as claimed in claim 1, is characterized in that: described Farsighted lens material is plastic cement.

4. Farsighted lens as claimed in claim 1, is characterized in that: described Farsighted lens parameter is Specification The aspheric surface Farsighted lens of design Diopter: 1.0D Optic diameter: 72mm First surface radius-of-curvature: 213.9041mm The second face curvature radius: 335.1565mm Quadric surface constant P: -6.3927 Asphericity coefficient: B：-8.8665×10 ^-8 C：8.287×10 ^-11 D：-2.973×10 ^-14 E：-1.1087×10 ^-17 Center thickness: 1.873mm Edge thickness: 1.001mm Axial height: 3.812mm Oblique fire astigmatism: 0 Index of refraction error: -0.056D Distortion: 1.226％ Weight: 7.114g 。

5. Farsighted lens as claimed in claim 1, is characterized in that: described Farsighted lens parameter is

Specification The aspheric surface Farsighted lens of design Diopter: 2D Optic diameter: 72mm First surface radius-of-curvature: 181.5909mm The second face curvature radius: 470.5473mm Quadric surface constant P: -8.1367 Asphericity coefficient: B：-1.7047×10 ^-7 C：1.2603×10 ^-10 D：-4.7475×10 ^-14 E：-6.0824×10 ^-18 Center thickness: 2.775mm Edge thickness: 1.000mm Axial height: 4.154mm Oblique fire astigmatism: 0 Index of refraction error: -0.115D Distortion: 2.335％ Weight: 9.276g 。

6. Farsighted lens as claimed in claim 1, is characterized in that: described Farsighted lens parameter is Specification The aspheric surface Farsighted lens of design Diopter: 3D Optic diameter: 72mm First surface radius-of-curvature: 158.0317mm The second face curvature radius: 791.7613mm Quadric surface constant P: -8.0105 Asphericity coefficient: B：-2.4955×10 ^-7 C：1.3738×10 ^-10 D：-4.6234×10 ^-14 E：-4.5764×10 ^-18 Center thickness: 3.660mm Edge thickness: 1.001mm Axial height: 4.478mm Oblique fire astigmatism: 0 Index of refraction error: -0.176D Distortion: 3.389％ Weight: 11.383g 。

7. Farsighted lens as claimed in claim 1, is characterized in that: described Farsighted lens parameter is

Specification The aspheric surface Farsighted lens of design Diopter: 4D Optic diameter: 72mm First surface radius-of-curvature: 132.2325mm The second face curvature radius: 1198.686mm Quadric surface constant P: -5.5079 Asphericity coefficient: B：-3.1912×10 ^-7 C：1.2857×10 ^-10 D：-3.0321×10 ^-14 E：-9.234×10 ^-18 Center thickness: 4.567mm Edge thickness: 1.001mm Axial height: 5.107mm Oblique fire astigmatism: 0 Index of refraction error: -0.237D Distortion: 4.371％ Weight: 13.558g 。