Optical lens

Abstract

The application provides an optical lens, which comprises seven lenses, characterized in that, from the object side to the imaging surface along the optical axis, the first lens has negative optical power, the object side is a convex surface, and the image side is a concave surface; the second lens has positive optical power, the object side is a concave surface, and the image side is a convex surface; a diaphragm; the third lens has positive optical power, the object side and the image side are both convex surfaces; the fourth lens has positive optical power, the object side is a concave surface, and the image side is a convex surface; the fifth lens has negative optical power, the object side and the image side are both concave surfaces; the sixth lens has positive optical power, the object side and the image side are both convex surfaces; the seventh lens has optical power, the object side is a convex surface, and the image side is a concave surface; the entrance pupil diameter EPD of the optical lens and the real image height IH corresponding to the maximum field of view angle satisfy 1.5 < IH / EPD < 2.0.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and in particular to an optical lens. Background Technology

[0002] With the increasing development of security monitoring, consumers have higher and higher requirements for security lenses. On the one hand, they require a wider field of view to monitor a larger range of targets. On the other hand, they consider the heat generated by the circuitry of surveillance cameras and the temperature drift that can occur in low-temperature operating environments, leading to unclear images. Furthermore, security lenses are not very effective at night, especially in terms of infrared confocal technology. Moreover, the difficulty of image capture increases exponentially due to the alternation of day and night, influenced by temperature and infrared imaging.

[0003] Therefore, it is essential to develop an optical lens with a wide field of view, high pixel count, low temperature drift, and infrared confocal focus to meet the needs of security monitoring. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide an optical lens that has the advantages of a wide field of view, high pixel count, low temperature drift, and infrared confocal focus.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] An optical lens comprising seven lenses, characterized in that, along the optical axis from the object side to the imaging plane, they are arranged as follows:

[0007] The first lens with negative optical power has a convex object side and a concave image side.

[0008] A second lens with positive optical power has a concave object side and a convex image side.

[0009] Aperture;

[0010] A third lens with positive optical power has convex surfaces on both its object side and image side.

[0011] The fourth lens with positive optical power has a concave object side and a convex image side.

[0012] The fifth lens with negative optical power has concave object-side and image-side surfaces;

[0013] The sixth lens has positive optical power, and both its object-side and image-side surfaces are convex.

[0014] The seventh lens, which has optical power, has a convex object side and a concave image side.

[0015] The entrance pupil diameter EPD of the optical lens and the true image height IH corresponding to the maximum field of view satisfy the following condition: 1.5 < IH / EPD < 2.0.

[0016] Preferably, the field of view (FOV) and aperture value (FNO) of the optical lens satisfy the following condition: 110° < FOV / FNO < 120°.

[0017] Preferably, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view satisfy: TTL / IH < 3.5.

[0018] Preferably, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view satisfy: 1.5 < IH / f < 2.0.

[0019] Preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 7.0 < f2 / f.

[0020] Preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy the condition: 1.5 < f4 / f < 4.0.

[0021] Preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 12.0 < |f7 / f|.

[0022] Preferably, the effective focal length f of the optical lens and the combined focal length f of the first lens to the second lens are... 12 Satisfy: -5.5 < f 12 / f<-3.5.

[0023] Preferably, the effective focal length f of the optical lens and the combined focal length f of the third to seventh lenses are... 37 Satisfy: 1.5 < f 37 / f<2.0.

[0024] Preferably, the total optical length TTL of the optical lens and the sum of the center thicknesses ∑CT of the first to sixth lenses along the optical axis satisfy: 0.6 < ∑CT / TTL < 0.7

[0025] Compared to existing technologies, the advantages of this invention are: by rationally combining the lens shapes and optical powers of each lens, low-cost mass production is achieved; the materials are inexpensive; the structure is simple; and assembly is easy. By optimizing the positive and negative optical powers of each lens, aberrations are effectively corrected. Furthermore, the lens overcomes the defect of plastic aspherical lenses, which are prone to focus drift in high and low temperature environments due to their large coefficient of thermal expansion, achieving focus stability within a temperature range of -20℃ to 60℃, making it suitable for various environments. It also enables confocal infrared and visible light, and image capture with a maximum field of view of 110°.

[0026] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0028] Figure 1 This is a schematic diagram of the structure of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 2 This is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 3 This is an F-Theta distortion curve of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 4 This is a relative illumination curve of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 5 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

[0033] Figure 6 This is an axial aberration curve of the optical lens in Embodiment 1 of the present invention.

[0034] Figure 7 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0035] Figure 8 This is a schematic diagram of the optical lens structure of Embodiment 2 of the present invention.

[0036] Figure 9 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0037] Figure 10 This is the F-Theta distortion curve of the optical lens in Embodiment 2 of the present invention.

[0038] Figure 11 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0039] Figure 12 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0040] Figure 13 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0041] Figure 14 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0042] Figure 15 This is a schematic diagram of the optical lens structure of Embodiment 3 of the present invention.

[0043] Figure 16 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0044] Figure 17 This is the F-Theta distortion curve of the optical lens in Embodiment 3 of the present invention.

[0045] Figure 18 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0046] Figure 19 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0047] Figure 20 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0048] Figure 21 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0049] Figure 22 This is a schematic diagram of the optical lens structure of Embodiment 4 of the present invention.

[0050] Figure 23 This is a field curvature curve diagram of the optical lens in Embodiment 4 of the present invention.

[0051] Figure 24 This is the F-Theta distortion curve of the optical lens in Embodiment 4 of the present invention.

[0052] Figure 25 This is a relative illumination curve of the optical lens in Embodiment 4 of the present invention.

[0053] Figure 26 This is the MTF curve of the optical lens in Embodiment 4 of the present invention.

[0054] Figure 27 This is an axial aberration curve of the optical lens in Embodiment 4 of the present invention.

[0055] Figure 28 This is a chromatic aberration curve of the optical lens in Embodiment 4 of the present invention. Detailed Implementation

[0056] To better understand the invention, various aspects of the invention will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of the invention and are not intended to limit the scope of the invention in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0057] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0058] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0059] In this article, 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. The surface of each lens closest to the subject 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.

[0060] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of the invention, the word "may" is used to mean "one or more embodiments of the invention." And the term "exemplary" is intended to refer to an example or illustration.

[0061] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0062] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0063] According to an embodiment of the present invention, the optical lens, from the object side to the image side, comprises, in sequence: a first lens, a second lens, an aperture stop, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a filter, and a protective glass.

[0064] In some embodiments, the first lens may have negative optical power, which helps to reduce the angle of incidence of light rays, thereby effectively distributing the large field of view on the object side. The object side of the first lens is convex, and the image side is concave, which can collect as much light as possible into the rear optical system, increasing the light transmission and providing a basic guarantee for the large aperture of the optical lens, while also helping to meet the requirements of high illumination. In addition, the first lens can use a high Abbe number material, for example, the Abbe number of the first lens satisfies Vd1 > 55, which helps to reduce chromatic aberration caused by the first lens and improve the imaging quality of the optical lens.

[0065] In some embodiments, the second lens may have positive optical power, which helps to suppress chromatic aberration in the optical lens and improve the imaging quality of the optical lens. The object-side surface of the second lens is concave, and the image-side surface is convex, which helps to make the refraction angle of light more gradual, so that the collected light rays can be smoothly gathered and enter the rear optical system, which is conducive to the miniaturization of the rear end of the lens.

[0066] In some embodiments, the third lens may have positive optical power, which helps to reduce the angle of light refraction and allows for a smooth transition of light path. Both the object-side and image-side surfaces of the third lens are convex, which can balance the coma generated by the third lens itself, while correcting spherical aberration and astigmatism of the optical lens, thereby improving the imaging quality of the optical lens.

[0067] In some embodiments, the fourth lens may have positive optical power, which helps to reduce the refraction angle of light and allows for a smooth transition in the light path. The object-side surface of the fourth lens is concave, and the image-side surface is convex, which helps to smooth the light path and balances the spherical aberration generated by the fourth lens itself, thereby improving the imaging quality of the optical lens.

[0068] In some embodiments, the fifth lens may have negative optical power, which is beneficial for increasing the imaging area of ​​the optical lens, while correcting chromatic aberration caused by the preceding lenses and improving the imaging quality of the optical lens. Both the object-side and image-side surfaces of the fifth lens are concave, which is beneficial for correcting various aberrations of the optical lens and improving its imaging quality. Furthermore, the fifth lens may use a high refractive index material; for example, the refractive index of the fifth lens may satisfy Nd⁵ ≥ 1.66, which is beneficial for reducing the lens aperture and thickness and improving image quality.

[0069] In some embodiments, the sixth lens may have positive optical power, which is beneficial for improving the ability to converge light rays at the edge of the field of view, while effectively controlling the overall optical length and reducing the size of the optical lens, thereby facilitating the miniaturization of the optical lens. Both the object-side and image-side surfaces of the sixth lens are convex, which can balance the coma generated by the sixth lens itself, while correcting the spherical aberration of the optical lens and improving the imaging quality of the optical lens.

[0070] In some embodiments, the object-side surface of the seventh lens is convex and the image-side surface is concave, which can balance various aberrations generated by the seventh lens itself, while transmitting more light beams to the imaging surface, improving the relative illumination of the edge field of view, avoiding the generation of vignetting, and improving the imaging quality of the optical lens.

[0071] In some embodiments, an aperture stop for limiting the light beam may be provided between the second lens and the third lens. The aperture stop may be located near the object side of the third lens, which can reduce the generation of optical lens ghosting and help to gather the light entering the optical system and reduce the rear port diameter of the optical lens.

[0072] In some embodiments, the relative refractive index temperature coefficient dn / dt of at least one of the first lens, second lens, fourth lens, and sixth lens satisfies: 60 × 10⁻⁶. -6 / ℃<dn / dt. Meeting the above range is beneficial for the optical system to achieve non-defocusing within a temperature range of -20℃ to 60℃, giving it the characteristic of good high and low temperature imaging performance.

[0073] In some embodiments, the aperture value FNO of the optical lens satisfies: FNO ≤ 1.00. Satisfying this range is beneficial for achieving large aperture characteristics, providing more incident light to the optical lens, and thus acquiring sufficient scene information.

[0074] In some embodiments, the maximum field of view (FOV) of the optical lens satisfies: 110° ≤ FOV. Meeting this range facilitates the achievement of wide-angle characteristics, thereby enabling the acquisition of more scene information and meeting the needs of large-area detection.

[0075] In some embodiments, the total optical length (TTL) of the optical lens and the true image height (IH) corresponding to the maximum field of view satisfy the condition: TTL / IH < 3.5. Meeting this range helps to achieve a balance between good imaging quality and miniaturized design in the optical lens, and can meet the requirements of the optical lens under different working conditions.

[0076] In some embodiments, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view satisfy the following condition: 1.5 < IH / f < 2.0. Satisfying this range can achieve a large image plane characteristic while ensuring the depth of field of the optical lens, thereby improving the imaging quality of the optical system.

[0077] In some embodiments, the optical back focal length (BFL) and effective focal length (f) of the optical lens satisfy the condition: 0.9 < BFL / f. Meeting this range helps to achieve a balance between good image quality and an easily assembleable optical back focal length, ensuring the image quality of the optical lens while reducing the assembly difficulty of the camera module.

[0078] In some embodiments, the entrance pupil diameter EPD of the optical lens and the true image height IH corresponding to the maximum field of view satisfy the following condition: 1.5 < IH / EPD < 2.0. Satisfying this range allows for a larger width of the light beam entering the optical lens, thereby improving the brightness of the optical lens at the image plane and avoiding vignetting, while also increasing the imaging area of ​​the optical lens.

[0079] In some embodiments, the field of view (FOV) and aperture value (FNO) of the optical lens satisfy the following condition: 110° < FOV / FNO < 120°. Meeting this range helps to expand the field of view and increase the aperture of the optical lens, achieving wide-angle and large-aperture characteristics. The wide-angle characteristic allows the optical lens to acquire more scene information, meeting the needs of large-area detection. The large aperture characteristic helps to mitigate the problem of rapid brightness decrease at the edges of the field of view caused by the wide-angle feature, thus also facilitating the acquisition of more scene information.

[0080] In some embodiments, the effective focal length f, the maximum half-field angle θ, and the true image height IH corresponding to the maximum half-field angle of the optical lens are... θ Satisfy: 0.55 < IH θ / (f×Tanθ)<0.65. Meeting this range helps reduce optical lens distortion and facilitates post-processing restoration using software algorithms.

[0081] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy the condition: -2.5 < f1 / f < -1.5. Satisfying this range allows the first lens to have appropriate negative optical power, which is beneficial for reducing the angle of incidence of the incident light, thereby effectively sharing the large field of view on the object side, and at the same time obtaining a larger field of view range.

[0082] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 7.0 < f2 / f. Satisfying this range allows the second lens to have appropriate positive optical power, which is beneficial for suppressing chromatic aberration in the optical lens and improving the imaging quality of the optical lens.

[0083] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy the condition: 2.0 < f3 / f < 3.0. Meeting this range allows the third lens to have appropriate positive optical power, which helps to converge light while reducing the light deflection angle, ensuring a smooth transition of light path and improving the imaging quality of the optical lens.

[0084] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy the condition: 1.5 < f4 / f < 4.0. Meeting this range allows the fourth lens to have appropriate positive optical power, which helps to converge light while reducing the light deflection angle, ensuring a smooth transition of light path and improving the imaging quality of the optical lens.

[0085] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy the condition: -2.0 < f5 / f < -1.0. Satisfying this range allows the fifth lens to have appropriate negative optical power, which is beneficial for increasing the imaging area of ​​the optical lens, while correcting chromatic aberration caused by the front lenses and improving the imaging quality of the optical lens.

[0086] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy the condition: 1.5 < f6 / f < 2.5. Satisfying this range allows the sixth lens to have appropriate positive optical power, which is beneficial for improving the light-gathering ability of the edge field of view, while effectively controlling the overall optical length to reduce the size of the optical lens, thereby facilitating the miniaturization of the optical lens.

[0087] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 12.0 < |f7 / f|. Satisfying this range allows the seventh lens to have appropriate optical power, which helps to suppress the angle of incidence of the edge field of view onto the imaging plane, effectively transmit more light beams to the imaging plane, and improve the imaging quality of the optical lens.

[0088] In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the first lens to the second lens are... 12 Satisfy: -5.5 < f 12 / f < -3.5. Meeting this range allows for a more stable light path into the rear of the optical lens by appropriately allocating the focal lengths of the first and second lenses. This helps reduce the difficulty of correcting various aberrations and improves the image quality of the optical lens.

[0089] In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the third to seventh lenses are... 37 Satisfy: 1.5 < f 37 / f < 2.0. Meeting the above range, by reasonably allocating the focal lengths of the third to seventh lenses, helps to balance various aberrations and improve the imaging quality of the optical lens.

[0090] In some embodiments, the radius of curvature R3 of the object-side surface and the radius of curvature R4 of the image-side surface of the second lens satisfy: 0.9 < R3 / R4 < 1.1. Satisfying the above range allows the object-side surface and the image-side surface of the second lens to achieve similar surface shapes, which is beneficial for balancing the field curvature of the second lens and improving the imaging quality of the optical lens.

[0091] In some embodiments, the sagitta Sag7 of the object side of the fourth lens and the half-aperture d7 of the object side of the fourth lens, and the sagitta Sag8 of the image side of the fourth lens and the half-aperture d8 of the object side of the fourth lens, respectively satisfy: -0.2 < Sag7 / d7 < -0.1, -0.4 < Sag8 / d8 < -0.2. Satisfying these ranges avoids the problem of uneven coating caused by excessive curvature of the object side of the fourth lens, reducing the processing difficulty of the fourth lens; it also facilitates the transmission of edge light to the rear end of the optical lens, improving the imaging quality of the optical lens.

[0092] In some embodiments, the total optical length TTL of the optical lens and the sum of the center thicknesses of the first to sixth lenses along the optical axis, ∑CT, satisfy the condition: 0.6 < ∑CT / TTL < 0.7. Satisfying this range can effectively compress the total length of the optical lens, while also benefiting the structural design and manufacturing process of the optical lens.

[0093] To achieve better optical performance, the lens employs multiple aspherical lenses, and the shapes of each aspherical surface of the optical lens satisfy the following equation:

[0094] ;

[0095] Where z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, and A, B, C, D, E, F, G, and H are the second, fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth order surface coefficients, respectively.

[0096] The present invention will be further described below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different; for specific differences, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0097] Example 1

[0098] Please see Figure 1The figure shows a schematic diagram of the structure of the optical lens provided in Embodiment 1 of the present invention. The optical lens includes, in sequence along the optical axis from the object side to the imaging plane: a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and a protective glass G2.

[0099] The first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0100] The second lens L2 has positive optical power, its object side S3 is concave, and its image side S4 is convex.

[0101] Aperture ST;

[0102] The third lens L3 has positive optical power, and its object side S5 and image side S6 are both convex surfaces.

[0103] The fourth lens L4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex.

[0104] The fifth lens L5 has negative optical power, and both its object side S9 and image side S10 are concave.

[0105] The sixth lens L6 has positive optical power, and both its object-side surface S11 and image-side surface S12 are convex.

[0106] The seventh lens L7 has negative optical power, and its object side S13 is convex, while its image side S14 is concave.

[0107] The filter G1 has both its object side S15 and image side S16 as planes.

[0108] The protective glass G2 has a flat surface on both the object side S17 and the image side S18.

[0109] The imaging plane S19 is a plane.

[0110] The relevant parameters of each lens in the optical lens of Example 1 are shown in Table 1-1.

[0111] Table 1-1

[0112]

[0113] The surface profile parameters of the aspherical lens in Example 1 are shown in Table 1-2.

[0114] Table 1-2

[0115]

[0116] Figure 2The field curvature curve of Example 1 is shown, which represents the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within ±0.06 mm, indicating that the optical lens can effectively correct the field curvature.

[0117] Figure 3 The F-Tanθ distortion curves for Example 1 are shown, representing the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents F-Tanθ distortion (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within ±40%, indicating that the optical lens can effectively correct F-Tanθ distortion.

[0118] Figure 4 The relative illumination curve of Example 1 is shown, which represents the relative illumination value at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 50% at the maximum half-field angle, indicating that the optical lens has good relative illumination.

[0119] Figure 5 The modulation transfer function (MTF) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this example is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0120] Figure 6 The diagram shows the axial aberration curves for Example 1, representing the aberrations of each wavelength along the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the diagram, the axial aberration offset is controlled within ±15 μm, indicating that the optical lens can effectively correct axial aberrations.

[0121] Figure 7The diagram shows the transverse chromatic aberration curves for Example 1, representing the chromatic aberration of each wavelength relative to the center wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value (unit: μm) of each wavelength relative to the center wavelength, and the vertical axis represents the normalized field of view. As can be seen from the figure, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±3 μm, indicating that the optical lens can excellently correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0122] Example 2

[0123] Please see Figure 8 The figure shows a schematic diagram of the structure of the optical lens provided in Embodiment 2 of the present invention. The optical lens includes, in sequence along the optical axis from the object side to the imaging plane: a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and a protective glass G2.

[0124] The first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0125] The second lens L2 has positive optical power, its object side S3 is concave, and its image side S4 is convex.

[0126] Aperture ST;

[0127] The third lens L3 has positive optical power, and its object side S5 and image side S6 are both convex surfaces.

[0128] The fourth lens L4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex.

[0129] The fifth lens L5 has negative optical power, and both its object side S9 and image side S10 are concave.

[0130] The sixth lens L6 has positive optical power, and both its object-side surface S11 and image-side surface S12 are convex.

[0131] The seventh lens L7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave.

[0132] The filter G1 has both its object side S15 and image side S16 as planes.

[0133] The protective glass G2 has a flat surface on both the object side S17 and the image side S18.

[0134] The imaging plane S19 is a plane.

[0135] The relevant parameters of each lens in the optical lens of Example 2 are shown in Table 2-1.

[0136] Table 2-1

[0137]

[0138] The surface profile parameters of the aspherical lens in Example 2 are shown in Table 2-2.

[0139] Table 2-2

[0140]

[0141] Figure 9 The field curvature curve of Example 2 is shown, which represents the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within ±0.06 mm, indicating that the optical lens can effectively correct the field curvature.

[0142] Figure 10 The F-Tanθ distortion curves for Example 2 are shown, representing the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents F-Tanθ distortion (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within ±40%, indicating that the optical lens can effectively correct F-Tanθ distortion.

[0143] Figure 11 The relative illumination curves for Example 2 are shown, representing the relative illumination values ​​at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the graph, the relative illumination value of the optical lens is still greater than 50% at the maximum half-field angle, indicating that the optical lens has good relative illumination.

[0144] Figure 12 The modulation transfer function (MTF) curve of Example 2 is shown, which represents the lens imaging modulation at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this example is above 0.4 throughout the entire field of view. Within the range of 0–160 lp / mm, the MTF curve decreases smoothly and uniformly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0145] Figure 13The axial aberration curve of Example 2 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the axial aberration offset is controlled within ±15μm, indicating that the optical lens can effectively correct axial aberration.

[0146] Figure 14 The diagram shows the transverse chromatic aberration curves for Example 2, representing the chromatic aberration of each wavelength relative to the center wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2 μm, indicating that the optical lens can excellently correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0147] Example 3

[0148] Please see Figure 15 The figure shows a schematic diagram of the structure of the optical lens provided in Embodiment 3 of the present invention. The optical lens includes, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and a protective glass G2.

[0149] The first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0150] The second lens L2 has positive optical power, its object side S3 is concave, and its image side S4 is convex.

[0151] Aperture ST;

[0152] The third lens L3 has positive optical power, and its object side S5 and image side S6 are both convex surfaces.

[0153] The fourth lens L4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex.

[0154] The fifth lens L5 has negative optical power, and both its object side S9 and image side S10 are concave.

[0155] The sixth lens L6 has positive optical power, and both its object-side surface S11 and image-side surface S12 are convex.

[0156] The seventh lens L7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave.

[0157] The filter G1 has both its object side S15 and image side S16 as planes.

[0158] The protective glass G2 has a flat surface on both the object side S17 and the image side S18.

[0159] The imaging plane S19 is a plane.

[0160] The relevant parameters of each lens in the optical lens of Example 3 are shown in Table 3-1.

[0161] Table 3-1

[0162]

[0163] The surface profile parameters of the aspherical lens in Example 3 are shown in Table 3-2.

[0164] Table 3-2

[0165]

[0166] Figure 16 The field curvature curve of Example 3 is shown, which represents the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within ±0.06 mm, indicating that the optical lens can effectively correct the field curvature.

[0167] Figure 17 The F-Tanθ distortion curves for Example 3 are shown, representing the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents F-Tanθ distortion (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within ±40%, indicating that the optical lens can effectively correct F-Tanθ distortion.

[0168] Figure 18 The relative illumination curve of Example 3 is shown, which represents the relative illumination value at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 50% at the maximum half-field angle, indicating that the optical lens has good relative illumination.

[0169] Figure 19The modulation transfer function (MTF) curve of Example 3 is shown, which represents the lens imaging modulation at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this example is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0170] Figure 20 The axial aberration curve of Example 3 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the axial aberration offset is controlled within ±15μm, indicating that the optical lens can effectively correct axial aberration.

[0171] Figure 21 The diagram shows the transverse chromatic aberration curves for Example 3, representing the chromatic aberration of each wavelength relative to the center wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the figure, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2 μm, indicating that the optical lens can excellently correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0172] Example 4

[0173] Please see Figure 22 The diagram shows a schematic of the structure of the optical lens provided in Embodiment 4 of the present invention. The optical lens includes, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and a protective glass G2.

[0174] The first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0175] The second lens L2 has positive optical power, its object side S3 is concave, and its image side S4 is convex.

[0176] Aperture ST;

[0177] The third lens L3 has positive optical power, and its object side S5 and image side S6 are both convex surfaces.

[0178] The fourth lens L4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex.

[0179] The fifth lens L5 has negative optical power, and both its object side S9 and image side S10 are concave.

[0180] The sixth lens L6 has positive optical power, and both its object-side surface S11 and image-side surface S12 are convex.

[0181] The seventh lens L7 has negative optical power, and its object side S13 is convex, while its image side S14 is concave.

[0182] The filter G1 has both its object side S15 and image side S16 as planes.

[0183] The protective glass G2 has a flat surface on both the object side S17 and the image side S18.

[0184] The imaging plane S19 is a plane.

[0185] The relevant parameters of each lens in the optical lens of Example 4 are shown in Table 4-1.

[0186] Table 4-1

[0187]

[0188] The surface profile parameters of the aspherical lens in Example 4 are shown in Table 4-2.

[0189] Table 4-2

[0190]

[0191] Figure 23 The field curvature curve of Example 4 is shown, which represents the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within ±0.08 mm, indicating that the optical lens can effectively correct the field curvature.

[0192] Figure 24 The F-Tanθ distortion curves for Example 4 are shown, representing the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents F-Tanθ distortion (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within ±40%, indicating that the optical lens can effectively correct F-Tanθ distortion.

[0193] Figure 25The relative illumination curves for Example 4 are shown, representing the relative illumination values ​​at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the graph, the relative illumination value of the optical lens is still greater than 50% at the maximum half-field angle, indicating that the optical lens has good relative illumination.

[0194] Figure 26 The modulation transfer function (MTF) curve of Example 4 is shown, which represents the lens imaging modulation at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this example is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0195] Figure 27 The axial aberration curve of Example 4 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the axial aberration offset is controlled within ±6μm, indicating that the optical lens can correct axial aberration very well.

[0196] Figure 28 The diagram shows the transverse chromatic aberration curves for Example 4, representing the chromatic aberration of each wavelength relative to the center wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the figure, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2 μm, indicating that the optical lens can excellently correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0197] Please refer to Table 5 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture number FNO, true image height IH, field of view FOV, and the values ​​corresponding to each conditional expression in the embodiments.

[0198] Table 5

[0199]

[0200] In summary, the optical lens of this invention achieves a wide field of view, high pixel count, low temperature drift, and infrared confocal effect by rationally combining the lens shapes and optical power of each lens.

[0201] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0202] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. 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 these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens comprising seven lenses, characterized in that, Along the optical axis from the object side to the imaging plane, the order is as follows: The first lens with negative optical power has a convex object side and a concave image side. A second lens with positive optical power has a concave object side and a convex image side. Aperture; A third lens with positive optical power has convex surfaces on both its object side and image side. The fourth lens with positive optical power has a concave object side and a convex image side. The fifth lens with negative optical power has concave object-side and image-side surfaces; The sixth lens has positive optical power, and both its object-side and image-side surfaces are convex. The seventh lens, which has optical power, has a convex object side and a concave image side. The entrance pupil diameter EPD of the optical lens and the true image height IH corresponding to the maximum field of view satisfy the following condition: 1.5 < IH / EPD < 2.

0.

2. The optical lens according to claim 1, characterized in that, The field of view (FOV) and aperture value (FNO) of the optical lens satisfy the following condition: 110° < FOV / FNO < 120°.

3. The optical lens according to claim 1, characterized in that, The total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view satisfy the following condition: 3.22≤TTL / IH<3.

5.

4. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view satisfy the following condition: 1.5 < IH / f < 2.

0.

5. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy the condition: 7.0 < f2 / f ≤ 9.

25.

6. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy the condition: 1.5 < f4 / f < 4.

0.

7. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy the following condition: 12.0 < |f7 / f| ≤ 49.

34.

8. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the combined focal length f of the first lens to the second lens 12 Satisfy: -5.5 < f 12 / f<-3.

5.

9. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the combined focal length f of the third to seventh lenses 37 Satisfy: 1.5 < f 37 / f<2.

0.

10. The optical lens according to claim 1, characterized in that, The total optical length TTL of the optical lens and the sum of the center thicknesses of the first to sixth lenses along the optical axis, ∑CT, satisfy the following condition: 0.6 < ∑CT / TTL < 0.7.

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