Wide-angle small-distortion high-definition all-glass lens

Abstract

The application discloses a wide-angle small-distortion high-definition all-glass lens, which comprises, in sequence from an object side to an image side along an optical axis of the lens, a first lens which is a non-spherical glass lens with negative refractive power, a second lens which is a spherical glass lens with negative refractive power, a third lens which is a spherical glass lens with positive refractive power, a fourth lens which is a spherical glass lens with positive refractive power, a fifth lens which is a spherical glass lens with positive refractive power, a sixth lens which is a spherical glass lens with negative refractive power, and a fifth lens and a sixth lens which are cemented lenses, and a seventh lens which is a non-spherical lens with positive refractive power. The application adopts seven glass lenses, and can simultaneously consider a visible light waveband and a near-infrared waveband. The F# of the visible light waveband can reach 2.5, the F# of the near-infrared waveband can reach 2.0, and the lens is matched with a 1 / 1.8-inch chip, so that a large field angle, small distortion, a large target surface and athermalization can be realized, and the lens has high cost performance.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and in particular to a wide-angle, low-distortion, high-definition all-glass lens suitable for industrial intelligent manufacturing and high-precision visual inspection. Background Technology

[0002] With the popularization and gradual maturation of intelligent manufacturing and machine vision technologies, the automation and intelligent transformation of the manufacturing industry, and the gradual replacement of human vision by machine vision, have created a strong demand for highly stable and high-precision industrial lenses. Simultaneously, with the continuous improvement of CMOS / CCD image sensor pixels and the large-scale implementation of AI vision algorithms, industrial lens technology is further developing towards large target surface adaptation, ultra-high resolution, low distortion, wide depth of field, industrial camera protection, and resistance to ambient light interference. Furthermore, with the iteration of domestic intelligent manufacturing policies and the process of domestic substitution of high-end equipment, industrial lenses are gradually shifting from early foreign brand dominance to a stage of breakthroughs in integrated R&D technologies encompassing domestic optical design, precision machining, and optical coating, becoming an indispensable key component for high-end intelligent inspection equipment.

[0003] With the widespread adoption of intelligent manufacturing technologies, machine vision has gradually replaced human vision, becoming a core technology supporting industrial automation inspection, precision positioning, defect identification, and intelligent sorting. This has created a rigid market demand for highly stable, high-precision, and highly adaptable industrial optical lenses. Simultaneously, the continuous improvement in pixel levels of CMOS and CCD image sensors and the large-scale application of AI vision algorithms are driving rapid iterations in industrial lens technology towards larger target surface adaptation, ultra-high resolution, ultra-low distortion, wide depth of field, wide temperature stability, and resistance to ambient light interference.

[0004] With the support of domestic substitution policies, China's industrial optics field has achieved breakthroughs in integrated technologies such as optical design, precision lens processing, and multi-layer optical coating. Industrial lenses are gradually breaking free from the monopoly of overseas brands and becoming an indispensable core component for high-end intelligent inspection equipment. However, conventional industrial wide-angle lenses currently on the market still have many technical shortcomings: First, wide-angle lenses with large field of view generally suffer from severe distortion and large edge imaging deformation errors, failing to meet the needs of high-precision industrial inspection for dimensional measurement and defect location; second, traditional wide-angle lenses have limited target surface adaptability, making it difficult to be compatible with 1 / 1.8-inch and 1 / 1.2-inch large target surface high-pixel chips, resulting in insufficient resolution and poor detail reproduction; third, their light transmission performance is limited, failing to simultaneously meet the high-definition imaging requirements of visible light and near-infrared bands, and their weak resistance to ambient light interference greatly restricts the detection accuracy and scene adaptability of machine vision equipment. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a wide-angle, low-distortion, high-definition all-glass lens that can be paired with a 1 / 1.8-inch lens and features high resolution, wide field of view, low distortion, and wide depth of field.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A wide-angle, low-distortion, high-definition all-glass lens defines the surface of the lens adjacent to the object plane as the object-side surface and the surface of the lens adjacent to the image plane as the image-side surface, arranged sequentially from the object-side to the image-side along the lens optical axis: The first lens is a glass lens with negative optical power, wherein the object side of the first lens is convex and the image side is concave. The second lens is a glass lens with negative optical power, and the object side of the second lens is convex and the image side is concave. The third lens is a glass lens with positive optical power, wherein the object side of the third lens is convex and the image side is concave. The fourth lens is a glass lens with positive optical power, wherein the object side of the fourth lens is convex and the image side is either flat or convex. The fifth lens is a glass lens with positive optical power, and the object side and the image side of the fifth lens are both convex. The sixth lens is a glass lens with positive optical power, wherein the object side of the sixth lens is concave and the image side is convex. The seventh lens is a glass lens with positive optical power, and the object side and the image side of the seventh lens are both convex. A filter, wherein the filter is disposed on the image-side surface of the seventh lens; An imaging surface is disposed on the image-side surface of the filter; in, The image-side surface of the fifth lens and the object-side surface of the sixth lens are cemented together to form a cemented lens.

[0008] Furthermore, in this invention, when any one of the first to seventh lenses is an aspherical surface, the aspherical surface of that lens satisfies the following aspherical lens curve equation:

[0009] Where Z is the distance vector from the origin of the aspherical surface at a height of r along the optical axis; c is the paraxial curvature of the aspherical surface (radius of curvature R = 1 / c, which is the reciprocal of curvature); k is the conic coefficient; Ai is the i-th order coefficient of the aspherical surface, and the higher order coefficients used in this invention are A4, A6, A8, A10, A12, A14, A16, A18, and A20.

[0010] Furthermore, an aperture stop is also provided along the optical axis of the lens, the aperture stop being disposed between the fourth lens and the fifth lens, or the aperture stop being disposed between the third lens and the fourth lens; Furthermore, the lens satisfies the following relationship: -3≤(f1+f2+f3) / f≤-2, 8≤(f4+f5+f7) / f≤15; Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f7 is the focal length of the seventh lens, and f is the total focal length of the lens. By using a combination of positive and negative focal lengths in the first three elements, edge distortion of the wide-angle system is effectively corrected. Optimization of the focal length of the positive-power lenses in the latter part of the lens improves the system's imaging resolution and depth of field.

[0011] Furthermore, the lens satisfies the following relationship: 0.2 ≤ tan(HFOV) / f ≤ 0.5, where HFOV is half of the lens's maximum field of view. This parameter precisely balances the matching relationship between the ultra-large field of view and the optical focal length, ensuring wide-angle imaging while also satisfying a large depth of field.

[0012] Furthermore, the lens satisfies the following relationship: 0.7 ≤ SAG1 / SAG2 ≤ 0.85, where SAG1 is the sag of the object-side surface of the first lens at half the maximum effective diameter of the light ray, and SAG2 is the sag of the image-side surface of the first lens at half the maximum effective diameter of the light ray. Optimizing the sag ratio of the first lens can effectively control the head size of the lens, enabling product miniaturization while improving incident light collection, reducing primary aberrations of the system, and enhancing edge imaging uniformity.

[0013] Furthermore, the lens satisfies the following relationship: 1.2 ≤ SD1 / IMGH ≤ 1.5, where SD1 is the maximum effective half-diameter of the light rays on the object side of the first lens, and IMGH is half the image height corresponding to the maximum field of view of the lens. This condition effectively ensures a reasonable relationship between the lens and the rear of the lens, ensuring that the lens size is not too large while maintaining performance, achieving miniaturization. At the same time, it adapts to the imaging needs of large target surfaces, ensures effective light incidence across the entire field of view, and avoids edge field-of-view light attenuation and vignetting problems.

[0014] Furthermore, the lens satisfies the following relationship: -1.95≤R13 / R14≤-1.5, where R13 is the radius of curvature of the object side of the seventh lens, and R14 is the radius of curvature of the image side of the seventh lens. Optimizing the curvature ratio of the last lens, accurately correcting residual aberrations, further compressing system distortion, and improving imaging resolution can effectively ensure that when the half-image height of the optical lens is 4.45mm, the angle of the principal ray incident on the detector will not exceed 10.5°. Matching the corresponding 1 / 1.8-inch and 1 / 1.2-inch detectors, there is no risk of color cast in the imaging, thereby effectively improving image clarity.

[0015] Furthermore, the lens satisfies the following relationship: 0.8 ≤ (CT2 + CT3 + CT4) / f ≤ 1.5, where CT2 is the center thickness of the second lens element, CT3 is the center thickness of the third lens element, and CT4 is the center thickness of the fourth lens element. By optimizing the ratio of the mid-section lens thickness to the focal length, the optical path structure is stabilized, and the mechanical stability and temperature stability of the lens are improved.

[0016] Furthermore, the lens satisfies the following relationship: 1.75 ≤ R3 / R5 ≤ 2.5, where R3 is the radius of curvature of the object side of the second lens and R5 is the radius of curvature of the object side of the third lens. Optimizing the curvature matching of the front lens can effectively ensure that the second and third lenses share the optical power of the first lens, effectively correct spherical aberration and coma, improve the full field of view imaging clarity, and ensure the relative illumination of the system while achieving small distortion.

[0017] Furthermore, the maximum field of view of the lens is FOV, which satisfies FOV≥105°, achieving an ultra-wide-angle monitoring range and meeting the needs of large-scale panoramic industrial inspection.

[0018] Furthermore, the lens of this invention has excellent light transmission performance, with an F# number of 2.5 in the visible light band and an F# number of 2.0 in the near-infrared single band. It has a large dual-band light transmission capacity and strong resistance to ambient light interference, making it suitable for imaging in complex industrial conditions, including day and night and light and dark environments.

[0019] Furthermore, the lens of this invention has excellent low distortion performance: when paired with a 1 / 1.8-inch detector chip, the system distortion is less than 3.7%; when paired with a 1 / 1.2-inch large target chip, the system distortion is less than 2.5%, which can meet the stringent low distortion requirements for high-precision dimensional measurement and defect detection.

[0020] Furthermore, this invention adopts an all-glass lens structure, which has excellent optical stability and can work stably in an ultra-wide temperature range of -40℃ to 105℃, maintaining high-pixel high-definition imaging effect throughout the process without problems such as temperature drift, blurring, or color difference.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention is a wide-angle optical imaging lens, which uses 2 aspherical lenses and 5 spherical lenses. By combining different refractive forces, it achieves small distortion while ensuring large aperture, large field of view, large depth of field and high pixel count.

[0022] The beneficial effects of this invention are: This invention employs a seven-element all-glass optical architecture, combined with a cemented design for the fifth and sixth lenses. By precisely defining multi-dimensional optical parameters, it can efficiently correct various optical aberrations such as spherical aberration, coma, field curvature, and distortion. It is compatible with mainstream large-area high-pixel image sensors of 1 / 1.8-inch and 1 / 1.2-inch sizes, achieving ultra-low distortion imaging with an ultra-large field of view (FOV) ≥ 105°. It balances large-area monitoring with high-definition detail reproduction, making it suitable for scenarios such as industrial panoramic scanning, batch inspection, and large-area positioning. It offers high imaging resolution and good image uniformity.

[0023] This invention possesses excellent dual-band light transmission performance, with visible light band F2.5 and near-infrared band F2.0. It has a large light transmission capacity and strong low-light imaging capability, effectively resisting light interference in complex industrial environments, realizing high-definition imaging in both visible and near-infrared bands, and has a wide range of scene adaptability.

[0024] This invention adopts an all-glass material design, which has excellent high and low temperature stability compared with glass-plastic hybrid lenses. It can work continuously and stably in an ultra-wide temperature industrial environment from -60℃ to 105℃ without focal length shift, image blur, or image quality degradation. It has extremely strong environmental adaptability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the lens structure in Example 1.

[0026] Figure 2 The image shows the MTF curve of the lens in Example 1 in the visible band of 0.435-0.656nm.

[0027] Figure 3 The image shows the MTF curve of the lens in Example 1 at 0.850 nm.

[0028] Figure 4 This is a graph showing the astigmatism and distortion curves of the lens in Example 1.

[0029] Figure 5 This is a schematic diagram of the lens structure in Example 2.

[0030] Figure 6 The image shows the MTF curve of the lens in Example 2 in the visible band of 0.435-0.656nm.

[0031] Figure 7 The image shows the MTF curve of the lens at 0.850 nm in Example 2.

[0032] Figure 8 This is a graph showing the astigmatism and distortion curves of the lens in Example 2.

[0033] Figure 9 This is a schematic diagram of the lens structure in Example 3.

[0034] Figure 10 The image shows the MTF curve of the lens in Example 3 in the visible band of 0.435-0.656nm.

[0035] Figure 11 The image shows the MTF curve of the lens at 0.850 nm in Example 3.

[0036] Figure 12 This is a graph showing the astigmatism and distortion curves of the lens in Example 3.

[0037] Figure 13 This is a schematic diagram of the lens structure in Example 4.

[0038] Figure 14 The image shows the MTF curve of the lens in Example 4 in the visible band of 0.435-0.656nm.

[0039] Figure 15 The image shows the MTF curve of the lens at 0.850 nm in Example 4.

[0040] Figure 16 This is a graph showing the astigmatism and distortion curves of the lens in Example 4. Detailed Implementation

[0041] 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. In this specification, the expressions "first," "second," "third," etc., are only used to distinguish one feature from another, and do not indicate any limitation on the features. The shape of a spherical or aspherical surface is not limited to the spherical or aspherical shapes shown in the drawings. The drawings are for illustrative purposes only and are not strictly drawn to scale.

[0042] In this invention, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region; if the lens surface is not defined as convex, concave, or flat, it means that the lens surface can be convex, concave, or flat. The surface of each lens closest to the object being photographed is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0043] Unless otherwise specified, all terms used in this invention (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the same meaning as they have in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so defined in this invention.

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0045] To better understand and implement the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0046] The main element symbols in the specific embodiments of the present invention are explained in Table 1.

[0047] Table 1

[0048] The data from various specific embodiments of the present invention are summarized in Table 2 below.

[0049] Table 2

[0050] Example 1 Reference Figure 1 The diagram shown is a schematic representation of the optical structure of the wide-angle, low-distortion, high-definition all-glass lens in this embodiment. In this embodiment, the lens has a total focal length f = 3.4016 mm, a visible light band FNO = 2.5, a near-infrared band FNO = 2.0, and a field of view FOV = 107.03°.

[0051] In this embodiment, the wide-angle, low-distortion, high-definition all-glass lens is arranged sequentially from the object side to the image side along the lens optical axis: The first lens 11 is a spherical glass lens with negative optical power, the object side of which is convex and the image side of which is concave. The second lens 12 is an aspherical glass lens with negative optical power, its object side is convex and its image side is concave. The third lens 13 is a spherical glass lens with positive optical power, its object side is convex and its image side is concave. The fourth lens 14 is a spherical glass lens with positive optical power, its object side is convex and its image side is flat; Aperture 10; The fifth lens 15 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The sixth lens 16 is a spherical glass lens with positive optical power. Its object side is concave and its image side is convex. The image side of the fifth lens 15 and the object side of the sixth lens 16 are cemented together to form a cemented lens. The seventh lens 17 is an aspherical glass lens with positive optical power, and its object side and image side are both convex. Filter 18; And imaging plane 19.

[0052] In this embodiment, the radius of curvature (in mm), center thickness d (in mm), refractive index (ND), and Abbe constant (VD) of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, and the seventh lens 17 are shown in Table 1-1.

[0053] Table 1-1

[0054] In Table 1-1, the radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. The center thickness represents the central axial distance from the current surface to the next surface. The refractive index represents the ability of the current lens material to deflect light. The Abbe number represents the dispersion characteristics of the current lens material.

[0055] In this embodiment, the aspherical surfaces of both the first lens 11 and the seventh lens 17 can be defined by the aforementioned aspherical lens curve equation. Table 1-2 shows the coefficients of the aspherical surfaces of each optical surface of the first lens 11 and the seventh lens 17.

[0056] Table 1-2

[0057] In this embodiment, the surface parameters of the aspherical lens follow the aspherical general formula defined by this invention. By matching the corresponding conic coefficients and polynomial coefficients of each order, the surface shape of the lens is precisely optimized, effectively correcting the global aberration of the lens and improving the image clarity and edge illumination uniformity.

[0058] refer to Figure 2The figure shows the MTF curves of the lens in this embodiment at different fields of view with a visible light wavelength of 0.435-0.656μm and a spatial frequency of 100lp / mm. The horizontal axis represents the spatial frequency, and the vertical axis represents the MTF value. As can be seen from the figure, at a spatial frequency of 100lp / mm, the MTF value of the center field of view is greater than 0.75, and the MTF value of the 0.9 field of view is greater than 0.6. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0059] refer to Figure 3 The figure shows the MTF curves of the lens in this embodiment at 0.850μm and a spatial frequency of 100lp / mm for different fields of view. The horizontal axis represents spatial frequency, and the vertical axis represents MTF value. As can be seen from the figure, at a spatial frequency of 100lp / mm, the MTF value in the center field of view is greater than 0.72, and the MTF value in the 0.9 field of view is greater than 0.38. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0060] refer to Figure 4 The figure shows the astigmatism and distortion curves of the lens in this embodiment. The vertical axis of both the astigmatism and distortion curves represents the field of view, the horizontal axis of the astigmatism curve represents the astigmatism value, and the horizontal axis of the distortion curve represents the distortion percentage. As can be seen from the figure, the absolute value of distortion across the entire field of view in this embodiment can be kept below 3.5%, meeting the requirement for small distortion at the field of view angle.

[0061] This embodiment provides a wide-angle, low-distortion, high-definition all-glass lens that can be paired with a 1 / 1.8-inch large-area sensor. While maintaining a field of view greater than 105°, it features low distortion, high resolution, and high relative illumination. This meets customers' needs for a wide field of view, low distortion, high resolution, and high relative illumination.

[0062] Example 2 Reference Figure 5 The diagram shown is a schematic representation of the optical structure of the wide-angle, low-distortion, high-definition all-glass lens in this embodiment. In this embodiment, the lens has a total focal length f = 3.5154 mm, a visible light band FNO = 2.5, a near-infrared band FNO = 2.0, and a field of view FOV = 105.27°.

[0063] In this embodiment, the wide-angle, low-distortion, high-definition all-glass lens is arranged sequentially from the object side to the image side along the lens optical axis: The first lens 11 is a spherical glass lens with negative optical power, the object side of which is convex and the image side of which is concave. The second lens 12 is an aspherical glass lens with negative optical power, its object side is convex and its image side is concave. The third lens 13 is a spherical glass lens with positive optical power, its object side is convex and its image side is concave. The fourth lens 14 is a spherical glass lens with positive optical power, its object side is convex and its image side is flat; Aperture 10 The fifth lens 15 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The sixth lens 16 is a spherical glass lens with positive optical power. Its object side is concave and its image side is convex. The image side of the fifth lens 15 and the object side of the sixth lens 16 are cemented together to form a cemented lens. The seventh lens 17 is an aspherical glass lens with positive optical power, and its object side and image side are both convex. Filter 18; And imaging plane 19.

[0064] In this embodiment, the radius of curvature (in mm), center thickness d (in mm), refractive index (ND), and Abbe constant (VD) of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, and the seventh lens 17 are shown in Table 2-1.

[0065] Table 2-1

[0066] In Table 2-1, the radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. The center thickness represents the central axial distance from the current surface to the next surface. The refractive index represents the ability of the current lens material to deflect light. The Abbe number represents the dispersion characteristics of the current lens material.

[0067] In this embodiment, the aspherical surfaces of both the first lens 11 and the seventh lens 17 can be defined by the aforementioned aspherical lens curve equation. Table 2-2 provides the coefficients of the aspherical surfaces of each optical surface of the first lens 11 and the seventh lens 17.

[0068] Table 2-2

[0069] In this embodiment, the surface parameters of the aspherical lens follow the aspherical general formula defined by this invention. By matching the corresponding conic coefficients and polynomial coefficients of each order, the surface shape of the lens is precisely optimized, effectively correcting the global aberration of the lens and improving the image clarity and edge illumination uniformity.

[0070] refer to Figure 6The figure shows the MTF curves of the lens in this embodiment at different fields of view with a visible light wavelength of 0.435-0.656μm and a spatial frequency of 100lp / mm. The horizontal axis represents the spatial frequency, and the vertical axis represents the MTF value. As can be seen from the figure, at a spatial frequency of 100lp / mm, the MTF value of the center field of view is greater than 0.75, and the MTF value of the 0.9 field of view is greater than 0.6. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0071] refer to Figure 7 The figure shows the MTF curves of the lens in this embodiment at 0.850μm and a spatial frequency of 100lp / mm for different fields of view. The horizontal axis represents spatial frequency, and the vertical axis represents MTF value. As can be seen from the figure, at a spatial frequency of 100lp / mm, the MTF value in the center field of view is greater than 0.72, and the MTF value in the 0.9 field of view is greater than 0.35. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0072] refer to Figure 8 The figure shows the astigmatism and distortion curves of the lens in this embodiment. The vertical axis of both the astigmatism and distortion curves represents the field of view, the horizontal axis of the astigmatism curve represents the astigmatism value, and the horizontal axis of the distortion curve represents the distortion percentage. As can be seen from the figure, the absolute value of distortion across the entire field of view in this embodiment can be kept below 3.7%, meeting the requirement for small distortion at the field of view angle.

[0073] Example 3 Reference Figure 9 The diagram shown is a schematic representation of the optical structure of the wide-angle, low-distortion, high-definition all-glass lens in this embodiment. In this embodiment, the lens has a total focal length f = 3.5169 mm, a visible light band FNO = 2.5, a near-infrared band FNO = 2.0, and a field of view FOV = 105°.

[0074] In this embodiment, the wide-angle, low-distortion, high-definition all-glass lens is arranged sequentially from the object side to the image side along the lens optical axis: The first lens 11 is a spherical glass lens with negative optical power, the object side of which is convex and the image side of which is concave. The second lens 12 is an aspherical glass lens with negative optical power, its object side is convex and its image side is concave. The third lens 13 is a spherical glass lens with positive optical power, its object side is convex and its image side is concave. The fourth lens 14 is a spherical glass lens with positive optical power, its object side is convex and its image side is flat; Aperture 10 The fifth lens 15 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The sixth lens 16 is a spherical glass lens with positive optical power. Its object side is concave and its image side is convex. The image side of the fifth lens 15 and the object side of the sixth lens 16 are cemented together to form a cemented lens. The seventh lens 17 is an aspherical glass lens with positive optical power, and its object side and image side are both convex. Filter 18; And imaging plane 19.

[0075] In this embodiment, the radius of curvature (in mm), center thickness d (in mm), refractive index (ND), and Abbe constant (VD) of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, and the seventh lens 17 are shown in Table 3-1.

[0076] Table 3-1

[0077] In Table 3-1, the radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane. The center thickness represents the central axial distance from the current surface to the next surface. The refractive index represents the ability of the current lens material to deflect light. The Abbe number represents the dispersion characteristics of the current lens material.

[0078] In this embodiment, the aspherical surfaces of both the first lens 11 and the seventh lens 17 can be defined by the aforementioned aspherical lens curve equation. Table 3-2 shows the coefficients of the aspherical surfaces of each optical surface of the first lens 11 and the seventh lens 17.

[0079] Table 3-2

[0080] In this embodiment, the surface parameters of the aspherical lens follow the aspherical general formula defined by this invention. By matching the corresponding conic coefficients and polynomial coefficients of each order, the surface shape of the lens is precisely optimized, effectively correcting the global aberration of the lens and improving the image clarity and edge illumination uniformity.

[0081] refer to Figure 10 The figure shows the MTF curves of the lens in this embodiment at different fields of view with a visible light wavelength of 0.435-0.656μm and a spatial frequency of 100lp / mm. The horizontal axis represents the spatial frequency, and the vertical axis represents the MTF value. As can be seen from the figure, at a spatial frequency of 100lp / mm, the MTF value in the center field of view is greater than 0.75, and the MTF value in the 0.9 field of view is greater than 0.57. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0082] refer to Figure 11The figure shows the MTF curves of the lens in this embodiment at 0.850μm and a spatial frequency of 100lp / mm for different fields of view. The horizontal axis represents spatial frequency, and the vertical axis represents MTF value. As can be seen from the figure, at a spatial frequency of 100lp / mm, the MTF value in the center field of view is greater than 0.72, and the MTF value in the 0.9 field of view is greater than 0.37. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0083] refer to Figure 12 The figure shows the astigmatism and distortion curves of the lens in this embodiment. The vertical axis of both the astigmatism and distortion curves represents the field of view, the horizontal axis of the astigmatism curve represents the astigmatism value, and the horizontal axis of the distortion curve represents the distortion percentage. As can be seen from the figure, the absolute value of distortion across the entire field of view in this embodiment can be kept below 3.5%, meeting the requirement for small distortion at the field of view angle.

[0084] Example 4 Reference Figure 13 The diagram shown is a schematic representation of the optical structure of the wide-angle, low-distortion, high-definition all-glass lens in this embodiment. In this embodiment, the lens has a total focal length f = 3.5121 mm, a visible light band FNO = 2.5, a near-infrared band FNO = 2.0, and a field of view FOV = 105.22°.

[0085] In this embodiment, the wide-angle, low-distortion, high-definition all-glass lens is arranged sequentially from the object side to the image side along the lens optical axis: The first lens 11 is a spherical glass lens with negative optical power, the object side of which is convex and the image side of which is concave. The second lens 12 is an aspherical glass lens with negative optical power, its object side is convex and its image side is concave. The third lens 13 is a spherical glass lens with positive optical power, its object side is convex and its image side is concave. Aperture 10; The fourth lens 14 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The fifth lens 15 is a spherical glass lens with positive optical power. Its object side is convex and its image side is convex. The image side of the fifth lens 15 and the object side of the sixth lens 16 are cemented together to form a cemented lens. The sixth lens 16 is a spherical glass lens with positive optical power, its object side is concave and its image side is convex. The seventh lens 17 is an aspherical glass lens with positive optical power, and its object side and image side are both convex. Filter 18; And imaging plane 19.

[0086] In this embodiment, the radius of curvature (in mm), center thickness d (in mm), refractive index (ND), and Abbe constant (VD) of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, and the seventh lens 17 are shown in Table 4-1.

[0087] Table 4-1

[0088] In Table 4-1, the radius of curvature represents the degree of curvature of the lens surface; a positive value indicates that the surface bends toward the image plane, and a negative value indicates that the surface bends toward the object plane. The center thickness represents the central axial distance from the current surface to the next surface. The refractive index represents the ability of the current lens material to deflect light, and the Abbe number represents the dispersion characteristics of the current lens material.

[0089] In this embodiment, the aspherical surfaces of both the first lens 11 and the seventh lens 17 can be defined by the aforementioned aspherical lens curve equation. Table 4-2 provides the coefficients of the aspherical surfaces of each optical surface of the first lens 11 and the seventh lens 17.

[0090] Table 4-2

[0091] In this embodiment, the surface parameters of the aspherical lens follow the aspherical general formula defined by this invention. By matching the corresponding conic coefficients and polynomial coefficients of each order, the surface shape of the lens is precisely optimized, effectively correcting the global aberration of the lens and improving the image clarity and edge illumination uniformity.

[0092] refer to Figure 14 The figure shows the MTF curves of the lens in this embodiment at different fields of view with a visible light wavelength of 0.435-0.656μm and a spatial frequency of 100lp / mm. The horizontal axis represents the spatial frequency, and the vertical axis represents the MTF value. As can be seen from the figure, at a spatial frequency of 100lp / mm, the MTF value of the center field of view is greater than 0.75, and the MTF value of the 0.9 field of view is greater than 0.6. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0093] refer to Figure 15 The figure shows the MTF curves of the lens in this embodiment at 0.850μm and a spatial frequency of 100lp / mm for different fields of view. The horizontal axis represents spatial frequency, and the vertical axis represents MTF value. As can be seen from the figure, at a spatial frequency of 100lp / mm, the MTF value in the center field of view is greater than 0.72, and the MTF value in the 0.9 field of view is greater than 0.35. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0094] refer to Figure 16 The figure shows the astigmatism and distortion curves of the lens in this embodiment. The vertical axis of both the astigmatism and distortion curves represents the field of view, the horizontal axis of the astigmatism curve represents the astigmatism value, and the horizontal axis of the distortion curve represents the distortion percentage. As can be seen from the figure, the absolute value of distortion across the entire field of view in this embodiment can be kept below 3.8%, meeting the requirement for small distortion at the field of view angle.

[0095] The above description merely illustrates several embodiments of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A wide-angle, low-distortion, high-definition all-glass lens, characterized in that: The surface of the lens adjacent to the object plane is defined as the object-side surface, and the surface of the lens adjacent to the image plane is defined as the image-side surface. These surfaces are arranged sequentially from the object-side to the image-side along the lens optical axis. The first lens is a glass lens with negative optical power, wherein the object side of the first lens is convex and the image side is concave. The second lens is a glass lens with negative optical power, and the object side of the second lens is convex and the image side is concave. The third lens is a glass lens with positive optical power, wherein the object side of the third lens is convex and the image side is concave. The fourth lens is a glass lens with positive optical power, wherein the object side of the fourth lens is convex and the image side is either flat or convex. The fifth lens is a glass lens with positive optical power, and the object side and the image side of the fifth lens are both convex. The sixth lens is a glass lens with positive optical power, wherein the object side of the sixth lens is concave and the image side is convex. The seventh lens is a glass lens with positive optical power, and the object side and the image side of the seventh lens are both convex. The image-side surface of the fifth lens and the object-side surface of the sixth lens are cemented together to form a cemented lens. The lens satisfies the following relationship: -3≤(f1+f2+f3) / f≤-2, 8≤(f4+f5+f7) / f≤15; Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f7 is the focal length of the seventh lens, and f is the total focal length of the lens.

2. The wide-angle, low-distortion, high-definition all-glass lens according to claim 1, characterized in that: The lens satisfies the following relationship: 0.2 ≤ tan(HFOV) / f ≤ 0.

5. Wherein: HFOV is half of the maximum field of view of the lens.

3. The wide-angle, low-distortion, high-definition all-glass lens according to claim 1, characterized in that: The lens satisfies the following relationship: 0.7 ≤ SAG1 / SAG2 ≤ 0.

85. Wherein, SAG1 is the sagitta of the object side of the first lens at the maximum effective diameter of half the aperture of the light ray, and SAG2 is the sagitta of the image side of the first lens at the maximum effective diameter of half the aperture of the light ray.

4. The wide-angle, low-distortion, high-definition all-glass lens according to claim 1, characterized in that: The lens satisfies the following relationship: 1.2 ≤ SD1 / IMGH ≤ 1.

5. Wherein, SD1 is the maximum effective half-diameter of the light rays on the object side of the first lens, and IMGH is half the image height corresponding to the maximum field of view of the lens.

5. A wide-angle, low-distortion, high-definition all-glass lens according to claim 1, characterized in that: The lens satisfies the following relationship: -1.95 ≤ R13 / R14 ≤ -1.

5. Where R13 is the radius of curvature of the object side of the seventh lens, and R14 is the radius of curvature of the image side of the seventh lens.

6. The wide-angle, low-distortion, high-definition all-glass lens according to claim 1, characterized in that: The lens satisfies the following relationship: 0.8 ≤ (CT2 + CT3 + CT4) / f ≤ 1.

5. Among them, CT2 is the center thickness of the second lens, CT3 is the center thickness of the third lens, and CT4 is the center thickness of the fourth lens.

7. A wide-angle, low-distortion, high-definition all-glass lens according to claim 1, characterized in that: The lens satisfies the following relationship: 1.75 ≤ R3 / R5 ≤ 2.

5. Wherein, R3 is the radius of curvature of the object side of the second lens, and R5 is the radius of curvature of the object side of the third lens.

8. A wide-angle, low-distortion, high-definition all-glass lens according to claim 1, characterized in that: The maximum field of view of the lens is FOV, which satisfies FOV≥105°.

9. A wide-angle, low-distortion, high-definition all-glass lens according to claim 1, characterized in that: The aperture of the lens is F#, which satisfies the following conditions: F#=2.5 in the visible light band and F#=2.0 in the near-infrared single band.

10. A wide-angle, low-distortion, high-definition all-glass lens according to any one of claims 1 to 9, characterized in that: Also set along the lens optical axis: An aperture stop, wherein the aperture stop is disposed between the fourth lens and the fifth lens, or the aperture stop is disposed between the third lens and the fourth lens; A filter, wherein the filter is disposed on the image-side surface of the seventh lens; An imaging surface is disposed on the image-side surface of the filter.

Images