Optical imaging lens and application

Abstract

The application discloses an optical imaging lens and application, and belongs to the technical field of optical lenses, and the structure comprises a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens with negative refractive power, a fifth lens with positive refractive power and a protective glass arranged in sequence along an optical axis from an object side to an image side, wherein the first lens, the third lens, the fourth lens and the fifth lens are all even aspheric lenses, and the second lens is a spherical lens; by reasonably distributing the refractive power of each lens and controlling the ratio of key curvature radii and air spacing, the optical imaging lens is long-focus, large-aperture and small-sized, and is applied to an AR glasses terminal.

Description

Technical Field

[0001] This invention belongs to the field of optical lens technology, specifically relating to a telephoto, large-aperture, miniaturized optical imaging lens suitable for AR glasses terminals. Background Technology

[0002] As the demand for first-person perspective shooting in large-scale, far-field scenarios such as concerts and sporting events increases with the use of augmented reality (AR) glasses, users are placing higher demands on the focal length of the glasses' cameras. Only with a sufficiently long focal length can distant details be clearly captured. At the same time, the pixel size of current image sensors is constantly shrinking, requiring lenses to maintain sufficient contrast transmission capabilities at correspondingly high spatial frequencies.

[0003] However, existing lens designs for AR glasses generally suffer from the following contradictions: On the one hand, to accommodate the limited installation space of the glasses, the total optical length is strictly limited to a very short range, resulting in traditional solutions only achieving shorter focal lengths, which cannot meet the needs of capturing details at long distances. On the other hand, achieving both a long focal length and a large aperture under the condition of limited total length significantly increases the difficulty of aberration correction. Higher-order spherical aberration, axial chromatic aberration, and the principal ray incident angle (CRA) of the edge field of view are difficult to control within an acceptable range, resulting in decreased edge illumination and color crosstalk. At the same time, the modulation transfer function (MTF) required for high-frequency resolution is difficult to reach the design calibration level at the widest aperture, failing to fully realize the performance potential of high-resolution sensors. In addition, to be compatible with protective glass and infrared cutoff filters, a certain amount of space needs to be reserved for the optical back focal length. However, existing compact lenses often sacrifice back focal length, making it difficult to accommodate necessary components and resulting in extremely sensitive assembly tolerances, making it difficult to guarantee mass production yield.

[0004] Patent application CN120610378A discloses an ultra-thin wide-angle small-head AR lens with a total optical length (TTL) of only 3.79–4.10 mm. However, since this solution pursues ultra-thinness by drastically compressing the total length, its optical design inevitably comes at the cost of an extremely short focal length and wide-angle characteristics in order to obtain a larger field of view. It has the disadvantages of having too short a focal length, being unable to clearly capture distant details, and being unable to meet the needs of long-range shooting in large-scale far-field scenes such as concerts and sports events.

[0005] Wang Yang et al. published "Design of Miniaturized Concentric Reflective Mobile Phone Lens" (Wang Yang, Wang Ning, Gu Zhiyuan, et al. Design of Miniaturized Concentric Reflective Mobile Phone Lens [J]. Infrared and Laser Engineering, 2021, 50(11):217-223.). This paper designed a mobile phone lens with an F-number of 1.8 and a total length of 2.7 mm. It achieved a high resolution level of 0.7 field-of-view MTF greater than 0.34 and full field-of-view MTF greater than 0.23 at a spatial cutoff frequency of 400 lp / mm. However, since this design requires a curved sensor with a pixel size of 1.25μm and an extremely compact structure with a total length of 2.7mm, its technical solution is highly dependent on the special hardware platform of the curved sensor. Moreover, the design focal length is only 2.7mm and the full field of view reaches 100°, which belongs to the ultra-wide-angle lens solution. It is difficult to directly transplant it to the AR glasses scenario. It has the disadvantages of being too dependent on specific hardware and being unable to directly reproduce its high-frequency resolution level in a long-focal compact structure adapted to conventional planar sensors.

[0006] Ying Yuan et al. published "Design of wide field of view pinhole lens for VR / AR image quality test" (Ying Y, Dewen C, Qiwei W, et al. Design of wide field of view pinhole lens for VR / AR image quality test[J]. OPTICS FRONTIER ONLINE 2020: OPTICS IMAGING AND DISPLAY, 2020, 11571.). This paper points out that simultaneously achieving a large field of view, high imaging performance, and low distortion in a compact pinhole lens is a recognized technical challenge. This paper designs a pinhole lens based on a 1-inch sensor, with a 100° field of view and a 4 mm entrance pupil diameter. In the final design, distortion is controlled within 2.5%, and the full-field modulation transfer function is greater than 0.3 at 161 line pairs / mm (lp / mm). Spherical aberration, chromatic aberration, and field curvature are all well corrected. The pinhole lens designed in this paper is used in the image quality inspection system of VR / AR head-mounted displays. It is an inspection lens rather than a shooting lens for user wearable devices. Its resolution evaluation frequency is only 161 lp / mm. It has the disadvantage of insufficient high-frequency resolution at the Nyquist frequency of about 600 lp / mm corresponding to a pixel size of 0.8μm, and it is difficult to directly reuse it for long-distance telephoto shooting scenarios in the first-person perspective of AR glasses. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the present invention aims to provide an optical imaging lens and its application in AR glasses terminals. The present invention employs a 5-lens structure, and by rationally allocating the optical power of each lens and controlling the key curvature radius ratio and air gap, it achieves a balance between long focal length, large aperture, and miniaturization within a compact overall length. Simultaneously, it effectively corrects edge field-of-view aberrations and principal ray angles, ensuring high-frequency resolution and reserving ample back focal length space.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An optical imaging lens includes, arranged sequentially along the optical axis from the object side to the image side: a first lens 1 with positive optical power, a second lens 2 with negative optical power, a third lens 3 with positive optical power, a fourth lens 4 with negative optical power, a fifth lens 5 with positive optical power, and a protective glass 6. Among them, the first lens 1, the third lens 3, the fourth lens 4, and the fifth lens 5 are all even-order aspherical lenses, and the second lens 2 is a spherical lens.

[0009] Optionally, it also includes an aperture stop S3, which is located between the first lens 1 and the second lens 2.

[0010] Optionally, the optical imaging lens satisfies: 0.87 ≤ f / TTL ≤ 0.95 Where f is the focal length of the optical imaging lens, TTL is the total optical length, and the total optical length is the distance from the object side surface S1 of the first lens to the image surface S14.

[0011] Optionally, the optical imaging lens satisfies: 0.36 ≤ R1 / f ≤ 0.44 Wherein, R1 is the radius of curvature of the object side surface S1 of the first lens.

[0012] Optionally, the optical imaging lens satisfies: 0.17 ≤ d34 / TTL ≤ 0.23 Wherein, d34 is the air gap between the third lens 3 and the fourth lens 4 on the optical axis.

[0013] Optionally, the material of the second lens 2 satisfies: 1.58 ≤ nd2 ≤ 1.68, 19.0≤ Vd2 ≤30.0 Wherein, nd2 is the refractive index of the second lens 2, and Vd2 is the Abbe number of the second lens 2.

[0014] Optionally, the material of the fourth lens 4 satisfies: 1.60 ≤ nd4 ≤ 1.95, 20.0 ≤ Vd4 ≤ 40.0 Wherein, nd4 is the refractive index of the fourth lens 4, and Vd4 is the Abbe number of the fourth lens 4.

[0015] Optionally, the optical imaging lens also satisfies: 0.17 ≤ BFL / f ≤ 0.25 Wherein, BFL is the distance from the image side S13 of the protective glass to the image plane S14.

[0016] Optionally, the total optical length (TTL) of the optical imaging lens is ≤15mm; the aperture number (F#, i.e., the ratio of the lens focal length to the entrance pupil diameter) is 1.8; the maximum half-image height is 3.9mm, which can completely cover the imaging surface with an image diameter of Φ7.8mm.

[0017] The optical imaging lens described in this invention can be applied to AR glasses terminals.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Significantly improved imaging quality: This invention adopts a five-element alternating optical power structure of positive-negative-positive-negative-positive, combined with multiple even-order aspherical lenses, to effectively correct spherical aberration, coma, and astigmatism. In addition, by reasonably controlling the ratio between the curvature radius S1 of the object side of the first lens and the focal length of the optical imaging lens, excessive concentration of optical power load on the first lens is avoided; at the same time, relying on the overall alternating positive and negative optical path layout, the light deflection and optical power effect are shared by multiple lenses, reducing the risk of aberrations caused by a single lens and effectively improving the overall imaging quality.

[0019] (2) Significantly enhanced high-frequency detail resolution: Under the tight constraint of strictly limited total optical length, this invention reasonably sets the ratio of the effective focal length of the optical imaging lens to the total optical length, effectively extending the equivalent focal length of the system without increasing the overall axial size of the lens, thereby achieving telephoto imaging characteristics within a miniaturized architecture; at the same time, the first lens 1, the third lens 3, the fourth lens 4, and the fifth lens 5 are all optimized with aspherical surface shapes, so that the lens maintains a high level of MTF value in the center field of view at a high spatial frequency of 600 lp / mm, and the size of the blur spot in the entire field of view is well controlled. The simulation results can corroborate the high-frequency detail imaging capability of this lens.

[0020] (3) Compact structure and convenient assembly, with outstanding feasibility for mass production: The present invention adopts a simple structure of five lenses plus protective glass 6, which is lightweight and low in cost. By reasonably allocating the center thickness and air gap of each lens and reserving sufficient optical back focal length BFL (i.e., the distance from the image side S13 of the protective glass to the image plane S14), sufficient physical gap is ensured between the protective glass 6 and the sensor package to avoid assembly interference.

[0021] In summary, this invention achieves balanced focal length distribution and effectively corrects various optical aberrations by using a five-piece optical path structure with alternating positive and negative elements and multiple aspherical surfaces to improve imaging quality. It also achieves telephoto characteristics within a limited and compact size, ensuring detail resolution at high spatial frequencies. Furthermore, the structure is rationally laid out, with sufficient optical back focus, and is small in size, meeting the actual usage requirements of AR terminals. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the two-dimensional optical path structure provided in Embodiment 1 of the present invention; Figure 2 This is a dot diagram provided in Embodiment 1 of the present invention; Figure 3 The MTF curve provided in Embodiment 1 of the present invention; Figure 4 The field curvature and distortion curves provided in Embodiment 1 of the present invention; Figure 5 The relative illumination curve provided in Embodiment 1 of the present invention.

[0024] Figure 6 This is a schematic diagram of the two-dimensional optical path structure provided in Embodiment 2 of the present invention; Figure 7 This is a dot diagram provided in Embodiment 2 of the present invention; Figure 8 This is an MTF curve diagram provided in Embodiment 2 of the present invention; Figure 9 The field curvature and distortion curves provided in Embodiment 2 of the present invention; Figure 10 The relative illumination curve provided in Embodiment 2 of the present invention.

[0025] Figure 11 This is a schematic diagram of the two-dimensional optical path structure provided in Embodiment 3 of the present invention; Figure 12 This is a dot plot provided in Embodiment 3 of the present invention; Figure 13 This is the MTF curve provided in Embodiment 3 of the present invention; Figure 14 The field curvature and distortion curves provided in Embodiment 3 of the present invention; Figure 15The relative illumination curve provided in Embodiment 3 of the present invention.

[0026] Wherein, 1 is the first lens; 2 is the second lens; 3 is the third lens; 4 is the fourth lens; 5 is the fifth lens; 6 is the protective glass; S1 is the object plane side of the first lens; S2 is the image plane side of the first lens; S3 is the aperture stop; S4 is the object plane side of the second lens; S5 is the image plane side of the second lens; S6 is the object plane side of the third lens; S7 is the image plane side of the third lens; S8 is the object plane side of the fourth lens; S9 is the image plane side of the fourth lens; S10 is the object plane side of the fifth lens; S11 is the image plane side of the fifth lens; S12 is the object plane side of the protective glass; S13 is the image plane side of the protective glass; and S14 is the image plane. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings.

[0028] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are merely 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 should fall within the scope of protection of the present invention.

[0029] It should be noted that the terminology used in the embodiments of the present invention is for the purpose of describing specific embodiments only and is not intended to limit the present invention. The terms "first," "second," etc., are only used to distinguish different components and do not indicate any order, quantity, or importance. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0030] Figure 1 , Figure 6 or Figure 11 These are schematic diagrams of a two-dimensional optical path structure of an optical imaging lens provided in embodiments of the present invention. (Reference) Figure 1 The optical imaging lens provided in this embodiment of the invention can be applied to AR glasses terminals, including a first lens 1 with positive optical power, a second lens 2 with negative optical power, a third lens 3 with positive optical power, a fourth lens 4 with negative optical power, a fifth lens 5 with positive optical power, and a protective glass 6 arranged sequentially along the optical axis from the object side to the image side. The first lens 1, third lens 3, fourth lens 4, and fifth lens 5 are all even-order aspherical lenses, and the second lens 2 is a spherical lens.

[0031] In specific implementation, refer to Figure 1The protective glass 6 is located on the side closest to the image plane to protect the photosensitive chip in the imaging sensor. It can be understood that optical power is the reciprocal of focal length, characterizing the ability of an optical imaging lens to deflect light. When the optical power is positive, the light refraction is converging; when the optical power is negative, the light refraction is diverging. The first lens 1 with positive optical power and the second lens 2 with negative optical power collect the incident light and initially correct aberrations. The third lens 3 with positive optical power and the fourth lens 4 with negative optical power further balance aberrations and lengthen the system focal length. Finally, the fifth lens 5 with positive optical power controls the light exit angle, ensuring that the principal ray angle (CRA) of the image plane meets the chip requirements (CRA≤10°). In Example 1, the focal length f of the optical imaging lens is 13.6073 mm, the total optical length TTL is 14.986 mm, the F# is 1.8, and the maximum image height is 3.9 mm, corresponding to Φ7.8 mm.

[0032] The imaging optical lens provided in this embodiment of the invention adopts a structure of 5 lenses (4 of which are even-order aspherical). Through the design of the lens shape and the reasonable allocation of the optical power of each lens, the control of the key curvature radius ratio and the air gap between the third lens 3 and the fourth lens 4, a telephoto lens with a total length ≤15mm and an F#=1.8, a large aperture, and a miniaturized design are achieved. At the same time, it meets the requirements of distortion within ±3%, CRA ≤10°, and relative illumination ≥80%, which is suitable for AR glasses to shoot at long distances in sports events, concerts and other scenarios.

[0033] Continue to refer to Figure 1 Optionally, the imaging optical lens also includes an aperture stop S3, which is located between the first lens 1 and the second lens 2 (specifically, the S3 surface is the aperture stop surface).

[0034] Optionally, the optical imaging lens satisfies the following condition: 0.87 ≤ f / TTL ≤ 0.95 Where f is the focal length of the optical imaging lens, and TTL is the total optical length, which is the distance from the vertex of the object-side surface of the first lens 1 to the image plane. Setting f / TTL within the above range ensures that a telephoto lens is achieved with an extremely short total length, enabling the optical imaging lens to capture distant objects, while avoiding an excessively long total length that would be unsuitable for AR glasses.

[0035] Optionally, the optical imaging lens satisfies: 0.36 ≤ R1 / f ≤ 0.44 Where R1 is the radius of curvature of the side surface S1 of the first lens. Controlling the curvature of the side surface of the first lens helps to enhance optical power, and together with a large aperture of F#=1.8, ensures sufficient light-gathering ability.

[0036] Optionally, the optical imaging lens satisfies: 0.17 ≤ d34 / TTL ≤ 0.23 Here, d34 represents the air gap between the third lens 3 and the fourth lens 4 on the optical axis. This large gap is a key structural feature for extending the focal length of an optical imaging lens, while also leaving space for the rear elements within a finite total length, which is beneficial for aberration balance.

[0037] Optionally, the material of the second lens 2 satisfies: 1.58 ≤ nd2 ≤ 1.68, 19.0 ≤ Vd2 ≤ 30.0 Wherein, nd2 is the refractive index of the second lens 2, and Vd2 is the Abbe number of the second lens 2. Through the above material selection, the second lens 2, as a negative lens, can provide sufficient dispersion and, in conjunction with the front and rear positive lenses, achromatic.

[0038] Optionally, the material of the fourth lens 4 satisfies: 1.60 ≤ nd4 ≤ 1.95, 20.0 ≤ Vd4 ≤ 40.0 Where nd4 is the refractive index of the fourth lens 4, and Vd4 is the Abbe number of the fourth lens 4. Using a negative lens with ultra-high refractive index and high dispersion can effectively correct chromatic aberration and improve image quality.

[0039] Optionally, the optical imaging lens also satisfies: 0.17 ≤ BFL / f ≤ 0.25 Wherein, BFL is the distance from the image side S13 of the protective glass to the image plane S14. A reasonable back focus to focal length ratio is set to ensure compatibility with the chip without increasing the overall length.

[0040] The surface sagitta of all even-order aspherical lenses in the optical imaging lens strictly follows the standard even-order aspherical equation: In the formula, This represents the surface sagitta parallel to the optical axis. The reference curvature at the surface vertex; It is the conic constant; This is the radial distance from the lens surface to the optical axis; Represents the coefficients of each higher-order even-order aspherical surface. Take the values ​​1, 2, 3, ... . According to optical design principles, the coefficients of the quadratic term... The physical effects are already included in the reference curvature In order to avoid variable redundancy, this embodiment... Its constant value is 0.

[0041] The optical imaging lens of the present invention will be described in detail below with reference to several specific embodiments.

[0042] Example 1: Table 1 shows the... Figure 1 The core parameters of the optical imaging lens corresponding to Example 1: Table 1 Core Parameters of Optical Imaging Lenses Parameter Relationship Example 1 lower limit value Upper limit f / TTL 0.91 0.87 0.95 R1 / f 0.41 0.36 0.44 d34 / TTL 0.20 0.17 0.23 nd2 1.66 1.58 1.68 Vd2 21.0 19.0 30.0 nd4 1.90 1.60 1.95 Vd4 37.1 20.0 40.0 BFL / f 0.19 0.17 0.25 In this embodiment 1, the parameters of each lens component of the optical imaging lens are shown in Table 2. The side of the lens on which light enters is the object side, and the side on which light exits is the image side. For example, the S1 surface of the first lens 1 is the object side, and the S2 surface is the image side. Other lenses will not be described here. The surface interval represents the central axial distance from the current surface to the next surface. The refractive index (nd) represents the ability of the material between the current surface and the next surface to deflect light. The blank space represents that the current position is air, and the refractive index is 1. The Abbe number (vd) represents the dispersion characteristics of the material between the current surface and the next surface.

[0043] Table 2. Basic Structure and Material Parameters of Optical Imaging Lenses Table 3 shows the design values ​​of the aspherical parameters in Example 1: Table 3 Design values ​​of aspherical parameters Face number A4 A6 A8 A10 A12 S1 -1.813E-04 -5.867E-06 -8.846E-08 -7.204E-09 0 S2 -3.823E-04 1.275E-05 -2.549E-07 4.377E-09 0 S6 -2.600E-03 -2.131E-04 -6.238E-06 -3.637E-07 0 S7 -1.637E-03 -4.488E-04 -6.933E-06 -1.237E-06 0 S8 1.761E-03 -3.784E-04 -2.414E-04 5.830E-05 -6.577E-06 S9 8.849E-04 -1.321E-05 -1.328E-04 2.563E-05 -2.328E-06 S10 -9.746E-03 4.051E-04 -1.019E-05 2.422E-07 0 S11 -0.012 5.096E-04 -2.361E-05 7.019E-07 0 Where -1.813E-04 indicates that the A4 coefficient of surface number S1 is -1.813 × 10⁻⁴. -4 .

[0044] Figure 2 This is a dot plot provided in Embodiment 1 of the present invention. The dot plot represents the distribution of light spots formed on the image plane after light passes through the optical system. The smaller the root mean square radius (RMS radius) of the light spot, the clearer the system image. Figure 2 As can be seen, the light spot is relatively concentrated in each field of view in this embodiment, and the RMS radius at the center field of view is controlled within the Airy disk radius, indicating that the system has good imaging resolution.

[0045] Figure 3 This is an MTF curve provided in Embodiment 1 of the present invention. The MTF curve reflects the system's contrast transfer capability at different spatial frequencies. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value (0~1). The higher the frequency and the larger the value on the curve, the sharper the image. Figure 3 As can be seen, the system exhibits a center field-of-view MTF value greater than 0.25 at a high spatial frequency of 600 lp / mm, demonstrating excellent high-frequency imaging performance and enabling high-definition detail reproduction, thus meeting the design requirements for high-resolution imaging.

[0046] Figure 4 The field curvature and distortion curves provided in Embodiment 1 of the present invention. Figure 4 In the left-hand coordinate system, the horizontal coordinate represents the magnitude of the field curvature, in mm; the vertical coordinate represents the normalized image height, which has no unit. Figure 4 As can be seen, the imaging optical system provided in this embodiment effectively controls field curvature. In the coordinate system on the right, the horizontal axis represents the magnitude of distortion, in units of %; the vertical axis represents the normalized image height, which has no unit. Figure 4 As can be seen, the distortion of the imaging optical system provided in this embodiment has been well corrected, and the imaging distortion is small.

[0047] Figure 5 This is a relative illumination curve of the imaging optical system provided in Embodiment 1 of the present invention. Relative illumination represents the ratio of light intensity at different field-of-view positions to the light intensity of the central field of view, reflecting the attenuation of brightness at the lens edges. The horizontal axis represents the normalized image height (0~1, 1 corresponds to a maximum image height of 3.9 mm), and the vertical axis represents the relative illumination (%). Figure 5 As can be seen, the relative illuminance of this embodiment is greater than 80%, and the curve decreases smoothly from the center to the edge without any drastic jumps.

[0048] Example 2: Table 4 shows the results. Figure 6 The core parameters of the optical imaging lens in the corresponding embodiment 2.

[0049] Table 4 Core Parameters of Optical Imaging Lenses Parameter Relationship Example 2 lower limit value Upper limit f / TTL 0.92 0.87 0.95 R1 / f 0.40 0.36 0.44 d34 / TTL 0.21 0.17 0.23 nd2 1.66 1.58 1.68 Vd2 20.6 19.0 30.0 nd4 1.88 1.60 1.95 Vd4 37.2 20.0 42.0 BFL / f 0.18 0.17 0.25 In this embodiment 2, the parameters of each lens component of the optical imaging lens are shown in Table 5.

[0050] Table 5. Basic Structure and Material Parameters of Optical Imaging Lenses On a lens, the side on which light enters is the object side, and the side on which light exits is the image side. For example, in the first lens 1, surface S1 is the object side and surface S2 is the image side. Other lenses will not be described here. The surface interval represents the central axial distance between the current surface and the next surface. The refractive index (nd) represents the ability of the material between the current surface and the next surface to deflect light. The space represents that the current position is air, and the refractive index is 1. The Abbe number (vd) represents the dispersion characteristics of the material between the current surface and the next surface.

[0051] Table 6 shows the design values ​​of the aspherical parameters in Example 2.

[0052] Table 6 Design values ​​of aspherical parameters Face number A4 A6 A8 A10 A12 S1 -2.127E-04 -7.558E-06 -3.405E-08 -1.301E-08 0 S2 -4.488E-04 1.898E-05 -5.580E-07 1.008E-08 0 S6 -3.194E-03 -2.138E-04 -5.335E-06 1.692E-07 0 S7 -3.144E-03 -5.053E-04 4.098E-06 -1.426E-06 0 S8 1.146E-05 2.465E-04 -4.861E-04 1.142E-04 -1.404E-05 S9 6.012E-04 1.897E-04 -1.829E-04 3.439E-05 -3.273E-06 S10 -7.645E-03 4.051E-04 -1.621E-05 4.351E-07 0 S11 -9.895E-03 5.096E-04 -2.567E-05 7.439E-07 0 Where -2.127E-04 indicates that the A4 coefficient of surface number S1 is -2.127 × 10⁻⁴. -4 .

[0053] Figure 7 This is a dot plot provided in Embodiment 2 of the present invention. The dot plot represents the distribution of light spots formed on the image plane after light passes through the optical imaging lens. The smaller the root mean square radius (RMS radius) of the light spot, the clearer the system image. Figure 7 As can be seen, the light spot is relatively concentrated in each field of view in this embodiment, and the RMS radius at the center field of view is controlled within the Airy disk radius, indicating that the system has good imaging resolution.

[0054] Figure 8 This is an MTF curve provided in Embodiment 2 of the present invention. The MTF curve reflects the system's contrast transfer capability at different spatial frequencies. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value (0~1). The higher the frequency and the larger the value on the curve, the sharper the image. Figure 8 As can be seen, the system exhibits a center field-of-view MTF value greater than 0.25 at a high spatial frequency of 600 lp / mm, demonstrating excellent high-frequency imaging performance and enabling high-definition detail reproduction, thus meeting the design requirements for high-resolution imaging.

[0055] Figure 9 The field curvature and distortion curves provided in Embodiment 2 of the present invention. Figure 9 In the left-hand coordinate system, the horizontal coordinate represents the magnitude of the field curvature, in mm; the vertical coordinate represents the normalized image height, which has no unit. Figure 9 As can be seen, the imaging optical system provided in this embodiment effectively controls field curvature. In the coordinate system on the right, the horizontal axis represents the magnitude of distortion, in units of %; the vertical axis represents the normalized image height, which has no unit. Figure 9 As can be seen, the distortion of the imaging optical system provided in this embodiment has been well corrected, and the imaging distortion is small.

[0056] Figure 10 This is a relative illumination curve of the imaging optical system provided in Embodiment 2 of the present invention. Relative illumination represents the ratio of light intensity at different field-of-view positions to the light intensity of the central field of view, reflecting the attenuation of brightness at the lens edges. The horizontal axis represents the normalized image height (0~1, 1 corresponds to a maximum image height of 3.9 mm), and the vertical axis represents the relative illumination (%). Figure 10 As can be seen, the relative illuminance of this embodiment is greater than 80%, and the curve decreases smoothly from the center to the edge without any drastic jumps.

[0057] Example 3: Table 7 shows the results. Figure 11The core parameter table of the optical imaging lens in the corresponding embodiment 3.

[0058] Table 7 Core Parameters of Optical Imaging Lenses Parameter Relationship Example 3 lower limit value Upper limit f / TTL 0.90 0.87 0.95 R1 / f 0.36 0.36 0.44 d34 / TTL 0.18 0.17 0.23 nd2 1.60 1.58 1.68 Vd2 28.1 19.0 30.0 nd4 1.66 1.60 1.95 Vd4 21.0 20.0 40.0 BFL / f 0.20 0.17 0.25 In this embodiment 3, the parameters of each lens component of the optical imaging lens are shown in Table 8.

[0059] Table 8. Basic Structure and Material Parameters of Optical Imaging Lenses On a lens, the side on which light enters is the object side, and the side on which light exits is the image side. For example, in the first lens 1, surface S1 is the object side and surface S2 is the image side. Other lenses will not be described here. The surface interval represents the central axial distance between the current surface and the next surface. The refractive index (nd) represents the ability of the material between the current surface and the next surface to deflect light. The space represents that the current position is air, and the refractive index is 1. The Abbe number (vd) represents the dispersion characteristics of the material between the current surface and the next surface.

[0060] Table 9 shows the design values ​​of the aspherical parameters in Example 3.

[0061] Table 9 Design values ​​of aspherical parameters Face number A4 A6 A8 A10 A12 S1 -4.402E-04 -1.063E-05 -2.191E-08 -5.567E-08 0 S2 -2.052E-03 9.343E-05 -3.209E-06 7.148E-08 0 S6 -4.454E-03 -2.024E-04 -9.816E-06 -1.022E-06 0 S7 -5.386E-04 -3.054E-04 -3.052E-05 1.837E-06 0 S8 4.770E-03 -2.386E-04 -4.820E-04 1.442E-04 -2.112E-05 S9 3.487E-03 -2.061E-04 -7.579E-05 1.964E-05 -2.264E-06 S10 -5.819E-03 4.051E-04 -2.299E-05 5.613E-07 0 S11 -7.307E-03 5.096E-04 -2.785E-05 7.130E-07 0 Where -4.402E-04 indicates that the A4 coefficient of surface number S1 is -4.402 × 10⁻⁴. -4 .

[0062] Figure 12 This is a dot plot provided in Embodiment 3 of the present invention. The dot plot represents the distribution of light spots formed on the image plane after light passes through the optical system. The smaller the root mean square radius (RMS radius) of the light spot, the clearer the system image. Figure 12 As can be seen, the light spot is relatively concentrated in each field of view in this embodiment, and the RMS radius at the center field of view is controlled within the Airy disk radius, indicating that the system has good imaging resolution.

[0063] Figure 13 This is an MTF curve provided in Embodiment 3 of the present invention. The MTF curve reflects the system's contrast transfer capability at different spatial frequencies. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value (0~1). The higher the frequency and the larger the value on the curve, the sharper the image. Figure 13 It can be seen that the system has a center field-of-view MTF value greater than 0.25 at a high spatial frequency of 600 lp / mm, demonstrating excellent high-frequency imaging performance and enabling high-definition detail reproduction, thus meeting the design requirements for high-resolution imaging.

[0064] Figure 14The field curvature and distortion curves provided in Embodiment 3 of the present invention. Figure 14 In the left-hand coordinate system, the horizontal coordinate represents the magnitude of the field curvature, in mm; the vertical coordinate represents the normalized image height, which has no unit. Figure 14 As can be seen, the imaging optical system provided in this embodiment effectively controls field curvature. In the coordinate system on the right, the horizontal axis represents the magnitude of distortion, in units of %; the vertical axis represents the normalized image height, which has no unit. Figure 14 As can be seen, the distortion of the imaging optical system provided in this embodiment has been well corrected, and the imaging distortion is small.

[0065] Figure 15 This is a relative illumination curve of the imaging optical system provided in Embodiment 3 of the present invention. Relative illumination represents the ratio of light intensity at different field-of-view positions to the light intensity of the central field of view, reflecting the attenuation of brightness at the lens edges. The horizontal axis represents the normalized image height (0~1, 1 corresponds to a maximum image height of 3.9 mm), and the vertical axis represents the relative illumination (%). Figure 15 As can be seen, the relative illuminance of this embodiment is greater than 80%, and the curve decreases smoothly from the center to the edge without any drastic jumps.

[0066] Based on the parameter limitations and simulation test results of multiple embodiments of the present invention, the rationality of the optical imaging lens structure design and the superiority of its optical performance can be fully verified. As shown in the parameter table of the embodiments, the core key parameters of the present invention are strictly controlled within preset upper and lower limits. These include the ratio of focal length to total optical length (f / TTL), the ratio of the radius of curvature of the object side surface of the first lens 1 to the focal length (R1 / f), the ratio of the air gap between the third lens 3 and the fourth lens 4 to the total optical length (d34 / TTL), and the refractive index (nd2, nd4), Abbe number (Vd2, Vd4), and the ratio of optical back focal length to focal length (BFL / f) of the key lenses. These parameters work together to provide reliable support for the overall optical performance of the lens.

[0067] Based on the scientific constraints of the aforementioned parameters, combined with a five-element alternating optical power structure (positive-negative-positive-negative-positive), a multi-element aspherical design, and reasonable material selection, this invention can effectively correct various monochromatic aberrations and chromatic aberrations, evenly distribute the optical power load, and avoid excessive load on any single lens. Simulation test results further corroborate that the lens exhibits concentrated and well-controlled spot size across all fields of view, resulting in good image resolution; excellent high-frequency MTF curve performance, demonstrating outstanding detail reproduction capability; and effective correction of field curvature and distortion, with controllable image deformation across the entire field of view. All optical indicators synergistically meet the design requirements, enabling the product to simultaneously achieve miniaturization, a large aperture, and telephoto imaging characteristics. The overall structure is compact and well-organized, adapting to the high-definition imaging needs of AR glasses terminals, further confirming the rationality and practical value of this design.

[0068] Obviously, the above embodiments are merely examples to clearly illustrate the technical solutions of the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications (e.g., adjusting aberration correction parameters) based on the above description. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An optical imaging lens, characterized in that, It includes the following elements arranged sequentially along the optical axis from the object side to the image side: a first lens (1) with positive optical power, a second lens (2) with negative optical power, a third lens (3) with positive optical power, a fourth lens (4) with negative optical power, a fifth lens (5) with positive optical power, and a protective glass (6). Among them, the first lens (1), the third lens (3), the fourth lens (4), and the fifth lens (5) are all even-order aspherical lenses, and the second lens (2) is a spherical lens.

2. The optical imaging lens according to claim 1, characterized in that, An aperture stop (S3) is also provided between the first lens (1) and the second lens (2).

3. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: 0.87 ≤ f / TTL ≤ 0.95 Where f is the focal length of the optical imaging lens, TTL is the total optical length, and the total optical length is the distance from the object side (S1) of the first lens to the image plane (S14).

4. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: 0.36 ≤ R1 / f ≤ 0.44 Wherein, R1 is the radius of curvature of the object side (S1) of the first lens, and f is the focal length of the optical imaging lens.

5. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens satisfies: 0.17 ≤ d34 / TTL ≤ 0.23 Wherein, d34 is the air gap between the third lens (3) and the fourth lens (4) on the optical axis, and TTL is the total optical length.

6. The optical imaging lens according to claim 1, characterized in that, The material of the second lens (2) satisfies: 1.58 ≤ nd2 ≤ 1.68, 19.0≤ Vd2 ≤30.0 Wherein, nd2 is the refractive index of the second lens (2), and Vd2 is the Abbe number of the second lens (2).

7. The optical imaging lens according to claim 1, characterized in that, The material of the fourth lens (4) satisfies: 1.60 ≤ nd4 ≤ 1.95, 20.0 ≤ Vd4 ≤ 40.0 Wherein, nd4 is the refractive index of the fourth lens (4), and Vd4 is the Abbe number of the fourth lens (4).

8. The optical imaging lens according to claim 1, characterized in that, The optical imaging lens also satisfies: 0.17 ≤ BFL / f ≤ 0.25 Wherein, BFL is the distance from the protective glass image side (S13) to the image plane (S14), and f is the focal length of the optical imaging lens.

9. The optical imaging lens according to claim 3 or 5, characterized in that, The total optical length (TTL) of the optical imaging lens is ≤15mm; the aperture number (F#) is 1.8; the maximum half-image height of the optical imaging lens is 3.9mm, which can completely cover the imaging surface with an image diameter of Φ7.8mm.

10. The application of an optical imaging lens according to any one of claims 1 to 9 to an AR glasses terminal.

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