TWI321230B - A design method of a hypermetropia lens - Google Patents

Description

1321230 IX. Description of the Invention: [Technical Field] The present invention relates to a method for designing a far-sighted ophthalmic lens, and more particularly to a method for designing a spectacle lens using an aspherical design. [Prior Art] Spectacle lenses for correcting myopia and hyperopia can be classified into two types, one being a negative lens and the other being a positive lens. In the demand for ophthalmic lenses, it is generally desired that the ophthalmic lenses have a light weight, a thin thickness, and a mirror-like performance, and have small aberrations, and the better-performing ophthalmic lenses largely depend on the spectacle design method.

The conventional spectacle lens design method uses a spherical design because in the spherical design, the aberration can only be corrected by adjusting the radius of curvature of the two surfaces, thereby making the center of the ophthalmic lens thicker and cumbersome. The applicant's Taiwan Patent No. 9312(8)5〇, filed on July 2, 2004, discloses a method for designing an aspherical negative lens. The design method of the aspherical negative lens is to first fix the lens to the lens surface. One surface, one side of the eye is the second side of the lens 'in order to make the thickness thin, take the first surface as a plane'. The second surface spherical design method is aspherical design method, the secret thickness can be effectively thinned, and Make the lens look good; however, the _ spherical surface Wei design method is not complete _ $ film design, if the design of the aspherical positive lens thickness thin H surface is flat, but because the second side is close to the eye When wearing, the eyes are more convex, so they cannot satisfy the requirements of the person. Stomach 8' to the lens

It is necessary. SUMMARY OF THE INVENTION The invention provides a design method for a farsighted ophthalmic lens which can design a better performance. The present invention is a method for designing a farsighted ophthalmic lens. Flute _ Mirror 'The steps of the method for designing the spectacle lens are as follows. 4 Take the face as a shallow concave surface, the first face according to the degree of the distance of the spectacle lens, the princess first function includes _ pole _, the performance 6 thickness value 'make it Reduce the initial value of the thick red red increment material-reading, t the far-mirror (four) meter method of the invention, first ___ green, 5 also got a good correction; the design introduces the quadratic constant, through ^Aspherical recording - get the gallbladder pulse energy, so that the design of the far-lens lens reversing the spherical retreat glasses # compared to the 'mixed good far-field mirror recording energy; material, optimize the influence of the recurve point, make the design The farsighted spectacle lens is easy to process. ~, [Embodiment]

The design method of the hyperopic ophthalmic lens of the present invention will be further described in conjunction with the specific embodiments. The method for designing the hyperopic ophthalmic lens of the present invention first defines that the surface of the eye that is not in close contact with the eye is the first surface of the lens, and one of the faces of the eye is the second surface of the lens. Take the radius of curvature of the first surface as Rl, the radius of curvature of the second surface is R2' η is the refractive index of the lens material, t is the thickness of the center of the lens, and the refractive index of the first surface f FKn-iyR! 'The refractive index of the second surface (4) (4) also The degree of the farsighted spectacle lens (yield) is the reciprocal of the focal length after the spectacle lens, and the formula is:

Fv= ^ + __η

Fv unit ^1/m' is usually represented by D. Generally, D=1〇〇 'We usually say that the degree of spectacle lens' is the value of Fv multiplied by the value of 100. The calculation formula of the spectacle lens degree is suitable for positive lens. Negative lenses are also suitable. From the perspective of "style", the distance of the spectacle lens material is certain, then the degree of the farsighted spectacle lens is determined by the R2 and t values.

In order to make the positive lens have a thin thickness, it is necessary to design it to have a suitable edge thickness e. The edge thickness e should not be too small. If it is too small, it will be easily broken. If it is too large, it will waste material and increase the weight. The edge thickness e is simultaneously related to the center thickness t, the first face curvature radius &, the ^ face curvature radius & At the time of design, the value of t is calculated from the target value of the edge thickness. After the value of t is determined, the values of the farsighted glasses are not changed by adjusting the R] and & values. The change of 艮 and 1 further affects the change of e. In order to keep the value unchanged, the center thickness t is adjusted, and then adjusted, and then optimized, and then sequentially, to calculate the satisfactory aspheric coefficient optimization value. At least one surface of the farsighted ophthalmic lens is designed to be aspherical, wherein the aspherical surface is calculated by the aspherical formula as 71321230 2= C〆+Br* +Cr6 +Dre + Br10 \+^-pcy where z is Mirror depth, cv represents the aspheric center curvature, r represents the vertical height from any point on the mirror surface to the center of the mirror, P is the quadratic constant value, and B, c, D, E represent the aspheric high-order coefficient. The design method of the hyperopic spectacle lens of the present invention takes the positive lens design process of the distance vision lens as 4D as an example, and the process is as follows: The schematic diagram of the conventional 4D spherical hyperopic ophthalmic lens 'Please refer to the first figure, wherein the first side of the spherical hyperopic ophthalmic lens The radius of curvature is Ri=55.08512 mm, the radius of curvature of the second face is R2=82.59859 mm, the thickness of the mirror center is t=6.134 mm, the thickness of the mirror edge is e=i 000626, the axial height of the mirror is ah=14.39197, and the diameter of the lens is DA=72 mm.

We use the aspheric design method to correct the above conventional design. Firstly, we design by the method of spherical design. At this time, the correction of the aberration is not considered in the design. The material of the farsighted ophthalmic lens is plastic. Here, PC (polycarbonate) is used. Density p=1.25g/mm3, refractive index nd=1 side, dispersion %=58 6, lens diameter DA=72mm 〇Aspherical positive lens design, in order to make the designed lens thin and flat, the first side needs to be defined as The spherical 'the second side is flat' but to protect the eyes, the second side is taken as a shallow concave surface. Face F2=(ln)/R2, calculated as R2 is 1172mm. To make the lens thinner, define e=lmm Ri=132.5mm, t=5.44mm. Then, based on the initial design, correct with aspherical optimization. Hyperopia_County. τ alone: (4) Surface 'We use the least squares method to optimize, first define _ performance function is small, the degree is minus 50 degrees, that is, F2 we take _〇.5D, then the second side, the first surface curvature The radius is calculated according to the formula, and at this time, the far-sighted spectacle lens is flat and thin, but the aberration is large.

KC Φ=

YjWOei -ti)f _ « .2 w Two Ui i=l where π is the weight factor, and its value is determined by Wi> 〇^ property, if the item in the position of •^ is equal to or greater than the integer of 丨, Ei is a larger factor for the correction factor m considered. The value of m is small, the target, the weight, the value = the expected value of $ 1321230, and each item can be represented by 乂. In the design of hyperopic ophthalmic lenses, the first thing we care about is the aberration ei. In order to make the aberration control on the second mirror surface more moderate, we take the aberration correction of three positions, including the 05 field of view. The oblique astigmatism, the oblique astigmatism of the 0.7 field of view angle, and the oblique astigmatism of the 〇·〇 field of view are denoted by ei, e2, es, respectively. Another - the correction factor considered is the distortion of the ι 〇 field of view, denoted by q. In addition, we must also consider the influence of the inflection point of the second side, which is represented by e5. The judgment of the inflection point can be judged by the second differential value of the mirror height r by the mirror depth s, that is, the extraction in the aspherical formula Second Derivative. If there is an inflection point, the value of the surface d2S/dr2 has a positive or negative sign, which can be judged. The last Φ value can be expressed as a function (1): 0=W, 2(ert1)2+ W22(e2-t2)2 +W32(e3-t3)2 +W42(e4-t4)2 +W52(e5-t5 ) 2 (1) One of the five square factors is related to the aspheric coefficients B, C, D, E and the quadric coefficient p, which can be expressed as (P, B, C, D, E) five variable parameters The function. In the aspheric formula, we take five variable design parameters (P, B, C, D, E), and finally the φ value is expressed as containing five variable parameters (p, B, c, D, E). function. We optimize the above formula (1), we can take each weight factor Wi=W2=W3=W4=W5=1, and the optimal value of the target value φ is controlled to be the best range, but it is generally difficult to achieve, we can The experience is defined as the Φ value - the range, the φ value will be smaller and smaller in the optimization process towel. To calculate the value of (P, B, C, D, E), we use the damped least squares method. Since the initial design, each ship C, D, E) has - initial value 'we use vector to represent, let (10) take the initial value, each has an initial value, we set to use. The value after optimization is expressed in tons, ¥3, ¥5), and the aberration is -Yuyu, 44 s). The X table does not have the value of X_XG. The solution of the damped least squares method can solve the value of the variation. The specific formula of the damped least squares solution is X=(ATA+PI)-, ATf〇3/ where A is five rows and five columns. The matrix, Ay= g·, U to ίτ5β, 疋fl, f2, f3, f4, f5 respectively for Xl, X2, X3, ~, X5 to obtain the partial derivative of the five-row column car; its transposition matrix of the frame, ρ is the damping representation -) negation matrix, through the multiplication of the above matrix ^ ^ through the 'can determine the value of X' and then can be obtained after the correction of the hunger take two different values to complete the first -: human optimization process, calculated (4) coffee, enter-step e=i.858_, 1321230 In order to make the edge thickness approx. lmm, the center thickness t needs to be subtracted from the edge thickness increment, ie, 5.441-0.8581^=4.583^, to ensure the degree of far-sighted glasses No change, further adjust the second-sided refractive index' The second optimization initial value is t=4.583, e=0.988mm, and then optimized. The result after the second optimization is t=4.583, e=1.016. By analogy, after multiple cycles of optimization, the edge thickness can be increased by 1 mm. The second figure is a schematic diagram of the optimized aspherical hyperopic ophthalmic lens. The third A and third B are the optimized results. The oblique astigmatism is 0, the refractive index error is -0.237D, and the distortion is 4_371〇/ 0. Finally, the value of Ri is determined by the number of degrees. See Table 1 for the results of the aspherical optimization design of the 4D hyperopic ophthalmic lens. Specifications Diopter: Lens diameter: radius of curvature of the first surface Semi-curvature of the second surface: Quadratic constant P: Aspherical coefficient: _Table 1 Design of aspherical hyperopic spectacle lens Spherical hyperopic spectacle lens of the same specification

4D 72mm 132.2325mm 1198.686mm -5.5079 B: -3.1912xl0'7 C: 1.2857xlO'10 D: -3.0321xl〇·14 E: -9.2340xl0'18 55.08512mm 82.59859mm No center thickness: Edge thickness: 4.567mm 1.001mm 6.134mm 1.000626mm

-----=------=Compared with the spherical hyperopic ophthalmic lens, the thickness of the edge is reduced, the axial height is reduced by 3Q%, and the spherical hyperopic lens is reduced. The thickness and quality of the hyperopic spectacle lens, while the hyperopic ophthalmic lens and the spherical hyperopic ophthalmic lens are more symmetrical than the aspherical hyperopic spectacle lens, and the field curvature is the average refractive index error 'all less than 0_25 range Inside, the distortion is less than 4.4%, so the method of designing the hyperopic ophthalmoscope 10 can meet the requirements. The present invention conforms to the invention patent requirements and is filed in accordance with the law. However, in the preferred embodiment of the invention, the person familiar with the skill of the present invention, in the thief, contains the _ the next _ please fill the inside of the first. The first picture is a schematic diagram of the conventional spherical hyperopia lens; The silly B picture after the design of the method for designing the far-sighted ophthalmic lens of the present invention is a schematic diagram of the aspherical lens of the method for designing the far-sighted lens of the present invention.

Claims (1)

^9«. Π· i S —— 年月R修(更)iE舒换-^Ι· '!' - -I 13212州-r', the patent application of the ML surface and the second surface of the hyperopic glasses, The second surface is set to be a shallow concave surface, and the flute is determined by using the aspherical optimization method for the first surface; the number, the performance function 4 I ^ positive aberration' The function and § 卯 卯 卯 其中 其中 其中 其中 其中 Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ The spherical coefficient function calculates the result by damping the busiest multiplication method; the initial value, the loop optimization is used to reduce the increment of the edge thickness as the next optimization. 2 The design method of the far-sighted ophthalmic lens described in the patent scope, the surface optimization method The financial application f spherical formula to calculate, the aspherical formula is aspheric ζ = ΪΓ ^ ^ Τ + do Ά) 8 + do 10 where ζ is the mirror depth, Cv represents the vertical height of the aspheric center curve center, P is - Female performance is the number of mirrors from the point on the mirror surface of the furnace β r^. For the human curve reading, B, C, D, E represent the aspherical high-order term 3 & such as Shen 4 specializes in her circumference. 2. Design method, = take five items '0·5 respectively Field angle oblique astigmatism ei, 〇7 shot, medium ^ 1 function medium angle oblique 2 astigmatism (1) distortion e4, inflection point e5, its formula A angle oblique image like e2, UM field 〇 = Wl (ertOV W22 (e2 -t2)2 + W32(e3-t3)2 + W42(e4-t4)2 + W52(es.t ^ 0 • The design method of the spectacle lens according to claim 3 of the patent application, 5) The inflection point is obtained by obtaining the second derivative of the aspherical calculation formula.