Prescription lenses for XR products and methods of making the same

Abstract

The application discloses a vision correction lens for an XR product and a manufacturing method thereof, the lens comprising a front surface and a rear surface, the front surface is arranged as a plane, and the rear surface is arranged as a curved surface, the manufacturing method specifically comprises the following steps: S1, constructing a three-dimensional eyeball simulation model containing human eye structure characteristics, and establishing a lens-eyeball joint optical model; S2, optimizing the integrated structure of the lens and the waveguide; S3, sampling lens grid data points point by point; S4, constructing a target evaluation function MF and an optimization parameter; and S5, calculating a correlation coefficient to construct a lens and a free ring curved surface profile. The application particularly distinguifies the differences between natural light and light from an XR waveguide sheet in wavelength and light component, can significantly improve the image distortion problem at the edge of the field of view under a large viewing angle, effectively improves the image quality and visual comfort of the XR glasses under the premise of ensuring the vision correction function, and simplifies the integrated structure of the lens and the waveguide.

Description

Technical Field

[0001] This invention relates to the fields of optometry and augmented reality technology, specifically to a vision correction lens for XR products and its manufacturing method. Background Technology

[0002] As the core optical device for correcting refractive errors, eyeglass lenses adjust the focusing of incident light to make the image clear on the retina. Their design requires treating the lens and the human eye as a joint optical system. From traditional spherical lenses to aspherical lenses, and then to freeform torus lenses, lens design has been constantly evolving: spherical lenses have significant distortion at the edge of the field of vision, while freeform lenses break through the constraints of symmetry and can optimize off-axis aberrations when the eye moves, achieving thinner lenses and clear vision across the entire field of vision. At the same time, they support personalized vision parameters and complex astigmatism correction. The advantage of freeform technology is that its three-dimensional curved surface design can simultaneously optimize aberrations at the center and the edge, and reduce the edge thickness of the lens, significantly improving wearing comfort.

[0003] The shortcomings of existing technology:

[0004] Currently, vision correction for XR devices faces unique challenges: when correcting the vision of XR device wearers, it is necessary to deal with diffracted light that differs significantly from natural light. Natural light is continuous, broadband, and unpolarized, while XR waveguide diffracted light is typically discrete RGB narrow spectrum, with narrow spectral width and linear polarization characteristics. This special usage scenario can cause additional compound aberrations such as polarization, chromatic aberration, and field curvature. Existing solutions have significant limitations: for example, custom-fitted insert lenses increase weight and affect eye-tracking accuracy; built-in mechanical adjustments can only adjust diopter and cannot solve astigmatism and chromatic aberration problems; in addition, when the field of view of XR devices expands to a large field of view exceeding 30°, the edge distortion rate of traditional designs usually exceeds 30%, causing significant image distortion and resulting in visual dizziness. Summary of the Invention

[0005] The purpose of this invention is to provide a vision correction lens for XR products and a method for manufacturing the same, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a vision correction lens for XR products, the lens comprising a front surface and a rear surface, the front surface being a plane and the rear surface being a curved surface.

[0007] The present invention also provides a method for manufacturing a refractive lens for XR products, the method specifically comprising:

[0008] S1. Construct a three-dimensional simulation model of the human eyeball that includes the structural features of the human eye, and establish a lens-eyeball joint optical model;

[0009] S2. Optimize the integrated structure of the lens and waveguide;

[0010] S3, sampling lens grid data points point by point;

[0011] S4. Construct the objective evaluation function MF and optimization parameters;

[0012] S5. Calculate the correlation coefficient to construct the lens and free torus surface profile.

[0013] Preferably, step S1 specifically involves constructing a coordinate system with the eyeball rotation center as the origin, and defining the line of sight and pitch angle during eyeball rotation. and left and right perspectives A coordinate system is constructed with the geometric center O of the lens as the origin. The X-axis and Y-axis correspond to the horizontal and vertical meridians, respectively, and the Z-axis corresponds to the optical axis direction, thus constructing a joint optical model of the lens and eyeball.

[0014] Preferably, step S2 includes the following steps:

[0015] a1. Design vision correction lenses with a flat front surface;

[0016] a2. Analyze the differences in wavelength and composition between natural light and light from the XR waveguide.

[0017] Preferably, step a2 specifically includes:

[0018] a21. Natural light refers to electromagnetic waves that reach the Earth's surface after being scattered by the atmosphere from solar radiation. The formula for defining the absolute spectral power distribution is:

[0019]

[0020] Where, h = 6.62607015 × 10 -34 J Let c be Planck's constant, and c = 2.998 × 10⁻⁶. 8 m / s is the speed of light in a vacuum. Boltzmann's constant, The wavelength of light C It is a proportionality constant;

[0021] a22. Light from a waveguide sheet is generated by electrical energy exciting a material. The formula for the absolute spectral power distribution is:

[0022]

[0023] in, The wavelength of light It is the full width at half maximum (FWHM) of the spectrum. , ;

[0024] a23. The spectrum in the visible light range cannot be decomposed into a finite number of discrete Gaussian terms, and the spectrum shows a continuous distribution without abrupt peaks; the spectrum of waveguide light in the visible light range consists of a blue light main peak and a broad yellow light peak, showing a discrete spectrum with characteristic peaks and the light source has a divergence angle.

[0025] Preferably, step S3 specifically involves: dividing the lens into M equal groups along the circumferential direction, sampling N=10 points radially in each group, for a total of [number of sampling points]. And M and N are both integers.

[0026] Preferably, step S4 specifically includes:

[0027] b1. Calculate beam astigmatism using the following formula:

[0028]

[0029] in , These are the meridional and sagittal refractive powers, respectively.

[0030] b2. Calculate the meridional and sagittal field curvatures of the beam using the following formula:

[0031] ;

[0032] Where y is the image height and f is the effective focal length;

[0033] b3. Calculate beam distortion using the following formula:

[0034]

[0035] in, The actual image height of the main ray. For the ideal image height;

[0036] b4. Construct the evaluation function, the formula is:

[0037]

[0038] in, Operand weights For operand values, The target value for the operand;

[0039] b5. The rear surface of the lens uses a biconical Zernike surface as its base, and the formula is:

[0040]

[0041] in, , Let x and y represent the curvatures in the x and y directions, respectively. , Represents the conic coefficient. , Represents higher-order coefficients of a freeform surface;

[0042] b6. Optimization is performed using a genetic algorithm. Based on the established evaluation function MF, the evaluation function of each sampling point of the freeform surface is obtained. Based on this, the corrected sag of each higher-order term is determined, and discrete data sampling points are obtained. The sag data of the discrete sampling points are fitted using the least squares method. Finally, the coefficients of each higher-order term of the biconical Zernike polynomial are determined, and the back surface of the freeform torus is established.

[0043] Preferably, in step b4, the design weights are... , , 1.5 , respectively, correspond to the operands of the astigmatic function Operands of the Field distorted operands Operands of the modulation transfer function .

[0044] Compared with the prior art, the beneficial effects of the present invention are:

[0045] This invention discloses a refractive lens for XR products and its manufacturing method. The front surface adopts a planar design, which can directly and tightly fit the XR waveguide sheet, eliminating the influence of air gaps on imaging and simplifying mechanical integration. The rear surface is based on the human eye-lens model. Taking into account the difference in wavelength composition between natural light and diffracted light, the freeform rear surface simultaneously corrects aberrations such as defocus, polarization, astigmatism, field curvature, and distortion. This invention ensures that the wearer's myopia and astigmatism are corrected within a large field of view, and can also effectively optimize aberrations such as field curvature and distortion. It breaks through the traditional bottleneck that it is difficult to achieve both a large field of view and aberration correction, giving the wearer a good visual experience when wearing XR devices. Attached Figure Description

[0046] Figure 1 This is a structural diagram of the lens-waveguide sheet of the present invention;

[0047] Figure 2 This is a three-dimensional mirror-eye model diagram of the present invention;

[0048] Figure 3 This is a standard dot diagram of the free-circular torus lens and the same specification spherical lens of the present invention;

[0049] Figure 4 The MTF diagrams for the free-circular torus lens and the same-specification spherical lens of the present invention are shown. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integrated connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a number" means two or more, unless otherwise explicitly specified.

[0054] Example

[0055] Please see Figure 1-4 As shown, the present invention provides a vision correction lens technical solution for XR products: the lens includes a front surface and a rear surface, the front surface is set as a plane and the rear surface is set as a curved surface.

[0056] This invention also provides a method for manufacturing a refractive lens for XR products, the method specifically including:

[0057] S1. Construct a three-dimensional simulation model of the human eyeball that includes structural features of the human eye, and establish a joint optical model of the lens and eyeball; construct a coordinate system with the center of eyeball rotation as the origin, and define the line of sight and pitch angle when the eyeball rotates. and left and right perspectives A coordinate system is constructed with the geometric center O of the lens as the origin. The X-axis and Y-axis correspond to the horizontal and vertical meridians, respectively, and the Z-axis corresponds to the optical axis direction, thus constructing a joint optical model of the lens and eyeball.

[0058] S2. Optimize the integrated structure of the lens and waveguide;

[0059] a1. Design vision correction lenses with a flat front surface;

[0060] a2. Analyze the differences in wavelength and composition between natural light and light from the XR waveguide sheet;

[0061] a21. Natural light refers to electromagnetic waves that reach the Earth's surface after being scattered by the atmosphere from solar radiation. The formula for defining the absolute spectral power distribution is:

[0062]

[0063] Where, h = 6.62607015 × 10 -34 J Let c be Planck's constant, and c = 2.998 × 10⁻⁶. 8 m / s is the speed of light in a vacuum. Boltzmann's constant, The wavelength of light C It is a proportionality constant;

[0064] a22. Light from a waveguide sheet is generated by electrical energy exciting a material. The formula for the absolute spectral power distribution is:

[0065]

[0066] in, The wavelength of light It is the full width at half maximum (FWHM) of the spectrum. , ;

[0067] a23. The spectrum in the visible light range cannot be decomposed into a finite number of discrete Gaussian terms, and the spectrum shows a continuous distribution without abrupt peaks; the spectrum of waveguide light in the visible light range consists of a blue light main peak and a broad yellow light peak, showing a discrete spectrum with characteristic peaks and the light source has a divergence angle.

[0068] S3. Sampling lens grid data points point by point; Divide the lens into M equal groups along the circumference, and sample N=10 points radially in each group, for a total of sampling points. And M and N are both integers;

[0069] S4. Construct the objective evaluation function MF and optimization parameters;

[0070] b1. Calculate beam astigmatism using the following formula:

[0071]

[0072] in , These are the meridional and sagittal refractive powers, respectively.

[0073] b2. Calculate the meridional and sagittal field curvatures of the beam using the following formula:

[0074] ;

[0075] Where y is the image height and f is the effective focal length;

[0076] b3. Calculate beam distortion using the following formula:

[0077]

[0078] in, The actual image height of the main ray. For the ideal image height;

[0079] b4. Construct the evaluation function, the formula is:

[0080]

[0081] in, Operand weights For operand values, The target value for the operand;

[0082] b5. The rear surface of the lens uses a biconical Zernike surface as its base, and the formula is:

[0083]

[0084] in, , Let x and y represent the curvatures in the x and y directions, respectively. , Represents the conic coefficient. , Represents higher-order coefficients of the freeform surface, design weights , , 1.5 , respectively, correspond to the operands of the astigmatic function Operands of the Field distorted operands Operands of the modulation transfer function ;

[0085] b6. Optimize using a genetic algorithm. Based on the established evaluation function MF, obtain the evaluation function of each sampling point of the free surface. Based on this, determine the corrected sag of each higher-order term and obtain discrete data sampling points. Fit the sag data of the discrete sampling points using the least squares method. Finally, determine the coefficients of each higher-order term of the biconical Zernike polynomial and establish the back surface of the free torus.

[0086] S5. Calculate the correlation coefficient to construct the lens and free torus surface profile.

[0087] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a refractive lens for XR products, characterized in that: The manufacturing method specifically includes the following steps: S1. Construct a three-dimensional simulation model of the human eyeball that includes the structural features of the human eye, and establish a lens-eyeball joint optical model; S2. Optimize the integrated structure of the lens and waveguide; Step S2 includes the following steps: a1. Design vision correction lenses with a flat front surface; a2. Analyze the differences in wavelength and composition between natural light and light from the XR waveguide sheet; S3, sampling lens grid data points point by point; The specific steps of step S3 are as follows: Divide the lens into M groups along the circumference, sample N=10 points radially in each group, and make a total of K=M×N=720 sampling points, where M and N are both integers; S4. Construct the objective evaluation function MF and optimization parameters; Step S4 specifically includes the following steps: b1. Calculate beam astigmatism using the following formula: in , These are the meridional and sagittal refractive powers, respectively. b2. Calculate the meridional and sagittal field curvatures of the beam using the following formula: ； Where y is the image height and f is the effective focal length; b3. Calculate beam distortion using the following formula: in, The actual image height of the main ray. For the ideal image height; b4. Construct the evaluation function, the formula is: in, Operand weights For operand values, The target value for the operand; b5. The rear surface of the lens uses a biconical Zernike surface as its base, and the formula is: in, , Let x and y represent the curvatures in the x and y directions, respectively. , Represents the conic coefficient. , Represents higher-order coefficients of a freeform surface; b6. Optimize using a genetic algorithm. Based on the established evaluation function MF, obtain the evaluation function of each sampling point of the free surface. Based on this, determine the corrected sag of each higher-order term and obtain discrete data sampling points. Fit the sag data of the discrete sampling points using the least squares method. Finally, determine the coefficients of each higher-order term of the biconical Zernike polynomial and establish the back surface of the free torus. S5. Calculate the correlation coefficient to construct the lens and free torus surface profile.

2. The method for manufacturing a refractive lens for XR products according to claim 1, characterized in that: Step S1 specifically involves constructing a coordinate system with the center of eye rotation as the origin, and defining the line of sight and pitch angle during eye rotation. and left and right perspectives A coordinate system is constructed with the geometric center O of the lens as the origin. The X-axis and Y-axis correspond to the horizontal and vertical meridians, respectively, and the Z-axis corresponds to the optical axis direction, thus constructing a joint optical model of the lens and eyeball.

3. The method for manufacturing a refractive lens for XR products according to claim 1, characterized in that: Step a2 specifically includes: a21. Natural light refers to electromagnetic waves that reach the Earth's surface after being scattered by the atmosphere from solar radiation. The formula for defining the absolute spectral power distribution is: Where, h = 6.62607015 × 10 -34 J Let c be Planck's constant, and c = 2.998 × 10⁻⁶. 8 m / s is the speed of light in a vacuum. Boltzmann's constant, The wavelength of light C It is a proportionality constant; a22. Light from a waveguide sheet is generated by electrical energy exciting a material. The formula for the absolute spectral power distribution is: in, The wavelength of light It is the full width at half maximum (FWHM) of the spectrum. , ; a23. The spectrum in the visible light range cannot be decomposed into a finite number of discrete Gaussian terms, and the spectrum shows a continuous distribution without abrupt peaks; the spectrum of waveguide light in the visible light range consists of a blue main peak and a broad yellow peak, showing a discrete spectrum with characteristic peaks and the light source has a divergence angle.

4. The method for manufacturing a refractive lens for XR products according to claim 1, characterized in that: In step b4, design weights , , 1.5 , respectively, correspond to the operands of the astigmatic function Operands of the Field distorted operands Operands of the modulation transfer function .

5. A refractive lens for XR products, characterized in that: The lens is prepared by the method described in claim 1, and includes a front surface and a rear surface, wherein the front surface is set as a plane and the rear surface is set as a curved surface.

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