Optical lens

Abstract

The application provides an optical lens which is composed of four lenses and sequentially comprises, along an optical axis from an object side to an imaging surface: a first lens with negative optical power, the object side of which is a convex surface and the image side of which is a concave surface; a second lens with positive optical power, the image side of which is a convex surface; a third lens with negative optical power, the object side of which is a concave surface and the image side of which is a convex surface; and a fourth lens with negative optical power, the object side of which is a concave surface and the image side of which is a convex surface; wherein the effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy 7<f / EPD<8. The optical lens provided by the application has one or more advantages such as long focal length, large F number small aperture, large depth of field and high relative luminance through specific surface shape matching and reasonable optical power distribution.

Description

Technical Field

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

[0002] With the continuous advancement of existing image processing algorithms and AI technologies, optical lenses are widely used in various fields such as smartphones, automotive lenses, QR code payment, action cameras, drones, and smart homes. Therefore, the performance requirements for optical lenses are becoming increasingly stringent. In some fields, such as QR code payment, optical lenses are required to capture image information, demanding high accuracy in capturing barcodes or scanning QR codes. However, most existing optical lenses require a specific distance for successful scanning and have relatively poor precision, failing to meet market demands. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide an optical lens that has one or more advantages such as telephoto, large F-number small aperture, large depth of field, and high relative illumination.

[0004] The technical solution adopted in this invention is as follows:

[0005] An optical lens, consisting of four lenses, arranged sequentially along the optical axis from the object side to the imaging plane:

[0006] The first lens with negative optical power has a convex object side and a concave image side.

[0007] A second lens with positive optical power has a convex image-side surface.

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

[0009] The fourth lens with negative optical power has a concave object side and a convex image side.

[0010] Wherein, the effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7 <f / EPD<8。

[0011] Further preferably, the effective focal length f of the optical lens and the radian of the maximum half-field angle θ of the optical lens satisfy: 9mm / rad <f / θ<12mm / rad。

[0012] Further preferably, the total optical length (TTL) of the optical lens and the effective focal length (f) of the optical lens satisfy: 1.5 <TTL / f<1.9。

[0013] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 0.2 <f2 / f<0.6。

[0014] More preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -3 < f3 / f < -0.5; the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 0.2 < R5 / R6 < 0.8.

[0015] More preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -20 < f4 / f < -1; the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0.2 < R7 / R8 < 0.8.

[0016] More preferably, the effective focal length f of the optical lens and the radius of curvature R4 of the image side surface of the second lens satisfy: -0.5 < R4 / f < -0.1.

[0017] More preferably, the effective focal length f of the optical lens and the radius of curvature R5 of the object side surface of the third lens satisfy: -0.5 < R5 / f < -0.05; the effective focal length f of the optical lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -0.8 < R6 / f < -0.1.

[0018] More preferably, the effective focal length f of the optical lens and the radius of curvature R7 of the object side surface of the fourth lens satisfy: -1 < R7 / f < -0.1; the effective focal length f of the optical lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -1.5 < R8 / f < -0.2.

[0019] More preferably, the mechanical clear aperture SD1 of the first lens and the mechanical clear aperture SD4 of the fourth lens satisfy: 0.35 < SD1 / SD4 < 0.5; the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -2 < R1 / R8 < -0.2.

[0020] Compared with the prior art, the optical lens provided by the present invention has a high relative illumination due to specific surface shape settings and reasonable optical power distribution. The object side surface of the first lens is convex, which helps to converge the incident light, reduces the head lens aperture, and is beneficial to head miniaturization. At the same time, the lens has a long focal length characteristic, which can better present larger local details, make the picture more concentrated and compact, so as to meet the local shooting requirements. The lens has a small aperture. Through the design of a large F-number and a small aperture, while ensuring the imaging quality of the lens, a longer depth of field range is achieved, so that when the image moves within a long range, the image can also be accurately collected. Description of the Drawings

[0021] 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:

[0022] Figure 1 This is a schematic diagram of the optical lens structure in Embodiment 1 of the present invention.

[0023] Figure 2 This is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0024] Figure 3 This is an axial aberration curve of the optical lens in Embodiment 1 of the present invention.

[0025] Figure 4 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0026] Figure 5 This is a relative illumination curve of the optical lens in Embodiment 1 of the present invention.

[0027] Figure 6 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0028] Figure 7 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0029] Figure 8 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0030] Figure 9 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 10 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 11 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0033] Figure 12 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0034] Figure 13 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0035] Figure 14 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0036] Figure 15 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0037] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0038] To better understand this application, various aspects of this application 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 this application and are not intended to limit the scope of this application 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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 this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0043] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0044] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will describe this application in detail with reference to the drawings and in combination with the embodiments.

[0045] The optical lens provided by the embodiment of the present invention is composed of four lenses, which are, in order from the object side to the imaging surface along the optical axis, the first lens, the second lens, the third lens, and the fourth lens.

[0046] In some embodiments, the first lens may have a negative optical power, its object side is convex, and its image side is concave. The second lens may have a positive optical power, and its image side is convex. The third lens may have a negative optical power, its object side is concave, and its image side is convex. The fourth lens may have a negative optical power, its object side is concave, and its image side is convex.

[0047] In some embodiments, the optical lens may further include an aperture for restricting the light beam. The aperture may be located between the first lens and the second lens, which can reduce the generation of ghosts in the optical lens and effectively reduce the difficulty of distortion correction of the lens.

[0048] In some embodiments, the effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7 < f / EPD < 8. Meeting the above conditions can make the lens have a smaller aperture. Through the design of a large F-number and small aperture, while ensuring the imaging quality of the lens, a longer depth of field range can be achieved, so that when the image moves within a longer range, the image can also be accurately captured. Specifically, the present invention can be used in fields such as code scanning payment, for example, the optical lens in a barcode scanner.

[0049] In some embodiments, the effective focal length f of the optical lens and the radian θ of the maximum half field angle of the optical lens satisfy: 9 mm / rad < f / θ < 12 mm / rad. Meeting the above conditions can make the lens have a larger focal length, which can better highlight the object to be photographed, blur the background, and achieve high-definition imaging of the object to be photographed within a specific distance.

[0050] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 1.9. Meeting the above conditions can reasonably control the ratio of the total length to the effective focal length of the optical lens, enabling the optical lens to have a short total length while achieving long focal length performance.

[0051] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 0.2 < f2 / f < 0.6. Meeting the above conditions, by setting the second lens to have a large positive refractive power, it is beneficial to the smooth transition of light, can effectively balance the aberration brought by the negative refractive power of the first lens, and improve the imaging resolution.

[0052] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -3 < f3 / f < -0.5; the object-side curvature radius R5 of the third lens and the image-side curvature radius R6 of the third lens satisfy: 0.2 < R5 / R6 < 0.8. Meeting the above conditions is beneficial to the smooth transition of light, better correcting the aberration and distortion brought by the previous lens, and improving the overall imaging quality.

[0053] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -20 < f4 / f < -1; the object-side curvature radius R7 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy: 0.2 < R7 / R8 < 0.8. Meeting the above conditions, by adjusting the focal length and meniscus shape of the fourth lens, the exit angle of light can be appropriately increased, thereby increasing the height of light focusing, increasing the photosensitive area of the image plane, and at the same time enabling the lens to have a high relative illumination, making the picture brightness of the captured image uniform, and facilitating subsequent image analysis and processing.

[0054] In some embodiments, the effective focal length f of the optical lens and the image-side curvature radius R4 of the second lens satisfy: -0.5 < R4 / f < -0.1. Meeting the above conditions, by reasonably setting the shape of the second lens, it is beneficial to converge light, reduce the difficulty of distortion correction, make the image in the edge field of view of the lens undistorted, and improve the overall imaging quality while achieving small distortion of the lens.

[0055] In some embodiments, the effective focal length f of the optical lens and the object-side curvature radius R5 of the third lens satisfy: -0.5 < R5 / f < -0.05; the effective focal length f of the optical lens and the image-side curvature radius R6 of the third lens satisfy: -0.8 < R6 / f < -0.1. Meeting the above conditions, by reasonably setting the shape of the third lens, it is beneficial to balance various aberrations of the lens, improve the imaging quality of the optical lens, while reducing the processing difficulty of the third lens and improving the processability.

[0056] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R7 of the object side surface of the fourth lens satisfy: -1 < R7 / f < -0.1; the effective focal length f of the optical lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -1.5 < R8 / f < -0.2. Meeting the above conditions is beneficial to balancing various aberrations of the lens, improving the imaging quality of the optical lens, reducing the processing difficulty of the fourth lens, and improving the processability.

[0057] In some embodiments, the mechanical clear aperture SD1 of the first lens and the mechanical clear aperture SD4 of the fourth lens satisfy: 0.35 < SD1 / SD4 < 0.5; the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: -2 < R1 / R8 < -0.2. Meeting the above conditions, by controlling the aperture and surface shape relationship of the first and last lenses in the lens, the relationship between the working aperture of the first lens and the image plane size can be balanced, enabling the lens to have a large image plane while having a small aperture, and achieving the balance of a small aperture and a large image plane of the lens.

[0058] In some embodiments, the focal length f of the optical lens and the true image height corresponding to the maximum field angle of the optical lens satisfy: 0.8 < f / IH < 0.9. Meeting the above conditions can not only achieve the telephoto characteristics of the lens to meet the local shooting requirements, but also achieve the large image plane characteristics of the lens, be able to match a larger size chip, and achieve high-pixel imaging of the lens.

[0059] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -8 < f1 / f < -0.5; the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 1 < R1 / R2 < 5. Meeting the above conditions, making the first lens a meniscus lens with negative refractive power helps to converge the incident light, reduces the aperture of the front lens, and is beneficial to the miniaturization of the front part.

[0060] In some embodiments, the first lens, the second lens, the third lens, and the fourth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberrations of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the second lens of the present invention can adopt a spherical lens, and the first lens, the third lens, and the fourth lens can adopt aspherical lenses.

[0061] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical lens provided by the present invention includes at least one glass lens and one plastic lens. The four-lens combination of glass and plastic has a good temperature drift effect and can also have good resolution in high and low temperature usage scenarios. More specifically, the second lens of the present invention can be a glass lens, and the first, third, and fourth lenses can be plastic lenses.

[0062] In some embodiments, the optical lens satisfies the conditional formula: 8mm < TTL < 10mm, 4.5mm < f < 6.5mm, 5.5mm < IH < 7mm, 7 < Fno < 8; where TTL represents the total optical length of the optical lens, f represents the effective focal length of the optical lens, IH represents the true image height corresponding to the maximum field angle of the optical lens, and Fno represents the aperture value of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least the characteristics of large image height, long focal length, large aperture, and miniaturization.

[0063] In each embodiment of the present invention, when the lens uses an aspherical lens, the surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0064]

[0065] where z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and B, C, D, E, F, G, H are the surface coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders respectively.

[0066] The present invention will be further described in multiple embodiments below. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are somewhat different. For specific differences, refer to the parameter tables of each embodiment. The following embodiments are only the preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any other changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0067] Embodiment 1

[0068] Please refer to Figure 1The diagram shown is a structural schematic of the optical lens 100 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, an aperture ST, a second lens L2, a third lens L3, a fourth lens L4, and a filter G1.

[0069] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0070] The second lens L2 has positive optical power, its object side surface S3 is a plane, and its image side surface S4 is a convex surface.

[0071] The third lens L3 has negative optical power, its object side S5 is concave, and its image side S6 is convex.

[0072] The fourth lens L4 has negative optical power, its object side S7 is concave, and its image side S8 is convex.

[0073] The object-side surface S9 and the image-side surface S10 of filter G1 are both planar.

[0074] The imaging plane S11 is a plane.

[0075] The first lens L1 is a glass spherical lens, while the second lens L2, the third lens L3, and the fourth lens L4 are plastic aspherical lenses.

[0076] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0077] Table 1-1

[0078]

[0079]

[0080] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0081] Table 1-2

[0082] Face number K B C D E F G H S1 -2.63E+00 1.21E-01 -4.36E-02 6.52E-02 -4.48E-02 5.24E-02 -4.56E-02 2.07E-02 S2 -4.57E+01 7.48E-01 -1.45E+00 2.23E+00 4.99E+00 -2.42E+01 3.47E+01 -1.24E+01 S5 2.74E-01 3.72E-01 3.99E-01 -3.95E-01 -1.96E-01 8.96E-01 -7.84E-01 3.41E-01 S6 -1.45E+00 1.51E-01 1.49E-01 2.47E-02 -9.29E-02 -1.02E-01 2.02E-01 -9.44E-02 S7 -8.20E+00 -6.29E-02 9.51E-03 3.10E-03 -8.12E-04 9.68E-05 -1.37E-05 1.13E-06 S8 -9.25E-03 -2.70E-02 2.62E-03 -4.38E-04 3.34E-05 2.69E-05 -8.99E-06 8.37E-07

[0083] In this embodiment, the field curvature curve, axial aberration curve, transverse chromatic aberration curve, and relative illumination curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown.

[0084] 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 field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within ±0.2 mm, indicating that the optical lens 100 can effectively correct the field curvature.

[0085] Figure 3 The diagram shows the axial aberration curves for Embodiment 1, which represent the aberrations of each wavelength along the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the diagram, the axial aberration offset is controlled within ±0.05 mm, indicating that the optical lens 100 can effectively correct axial aberrations.

[0086] Figure 4 The diagram shows the transverse chromatic aberration curves for Example 1, representing the chromatic aberration of each wavelength relative to the center wavelength (0.550 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 100 can effectively correct chromatic aberration at the edge of the field of view and the secondary spectrum of the entire image plane.

[0087] Figure 5 The relative illumination curves for Example 1 are shown, representing the relative illumination values ​​at different field-of-view angles on the imaging plane. The horizontal axis represents the field-of-view angle (unit: °), and the vertical axis represents the relative illumination. As can be seen from the figure, the relative illumination value of the optical lens 100 is still greater than 0.8 at the edge of the field of view, indicating that the optical lens 100 has good relative illumination.

[0088] Example 2

[0089] Please see Figure 6 The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S3 of the second lens L2 is a convex surface, and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0090] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0091] Table 2-1

[0092]

[0093] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0094] Table 2-2

[0095] Face number K B C D E F G H S1 1.22E+01 8.22E-02 -3.25E-02 5.74E-03 3.93E-03 -1.62E-03 -6.64E-04 3.81E-04 S2 1.49E+00 1.30E-01 1.30E-01 -5.83E-01 1.21E+00 -1.04E+00 1.20E-01 3.05E-01 S5 8.44E-01 1.38E-01 -2.78E-02 6.25E-01 -1.46E+00 3.12E+00 -4.49E+00 3.74E+00 S6 -1.24E+01 -5.47E-03 4.97E-02 3.15E-02 -3.49E-02 -5.66E-03 1.81E-02 -7.34E-03 S7 -1.47E+01 -5.17E-02 1.18E-02 1.44E-03 -6.56E-04 3.72E-05 9.34E-06 -1.15E-06 S8 -9.01E+00 -2.68E-02 1.10E-03 1.09E-04 -5.87E-07 -2.14E-06 -6.77E-07 1.00E-07

[0096] In this embodiment, the field curvature curve, axial aberration curve, transverse chromatic aberration curve, and relative illumination curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Figure 9 , Figure 10 As shown. From Figure 7 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.1mm, indicating that the optical lens 200 can effectively correct field curvature. From Figure 8 As can be seen, the axial aberration offset is controlled within ±0.02mm, indicating that the optical lens 200 can effectively correct axial aberration. From Figure 9 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1.5μm, indicating that the optical lens 200 can excellently correct chromatic aberration at the edges of the field of view and the second-order spectrum of the entire image plane. From Figure 10 As can be seen, the relative illumination value of optical lens 200 is still greater than 0.8 at the edge of the field of view, indicating that optical lens 200 has good relative illumination.

[0097] Example 3

[0098] Please see Figure 11 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S3 of the second lens L2 is a convex surface, and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0099] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0100] Table 3-1

[0101]

[0102] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0103] Table 3-2

[0104] Face number K B C D E F G H S1 -6.18E-01 1.66E-01 -2.11E-01 3.71E-01 -3.38E-01 1.16E-01 0.00E+00 0.00E+00 S2 2.82E+00 1.02E-01 6.09E-01 -3.81E+00 6.38E+00 -5.93E+00 0.00E+00 0.00E+00 S5 -8.76E-01 7.09E-02 -5.64E-02 3.03E-01 -5.72E-01 1.21E-01 0.00E+00 0.00E+00 S6 -5.34E+00 -1.61E-01 1.49E-01 -2.79E-02 -5.80E-03 1.84E-03 0.00E+00 0.00E+00 S7 -5.60E-01 -6.49E-02 7.20E-03 5.56E-03 -8.69E-04 1.25E-05 0.00E+00 0.00E+00 S8 2.57E+00 -6.47E-02 1.24E-02 -7.49E-04 -1.63E-04 2.45E-05 0.00E+00 0.00E+00

[0105] In this embodiment, the field curvature curve, axial aberration curve, transverse chromatic aberration curve, and relative illumination curve of the optical lens 300 are respectively as follows: Figure 12 , Figure 13 , Figure 14 , Figure 15 As shown. From Figure 12As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.4mm, indicating that the optical lens 300 can effectively correct field curvature. From Figure 13 As can be seen, the axial aberration offset is controlled within ±0.05mm, indicating that the optical lens 300 can effectively correct axial aberration. Figure 14 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±4μm, indicating that the optical lens 300 can excellently correct chromatic aberration at the edge of the field of view and the second-order spectrum of the entire image plane. From Figure 15 As can be seen, the relative illumination value of optical lens 300 is still greater than 0.75 at the edge of the field of view, indicating that optical lens 300 has good relative illumination.

[0106] Please refer to Table 4 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, true image height IH corresponding to the maximum field of view, maximum field of view FOV, and the values ​​corresponding to each conditional expression in each embodiment.

[0107] Table 4

[0108] Parameters and conditional expressions Example 1 Example 2 Example 3 f(mm) 5.290 5.275 5.197 FOV (°) 60 60 60 TTL(mm) 8.770 9.000 9.000 Fno 7.557 7.535 7.424 IH(mm) 6.115 6.112 6.129 EPD (mm) 0.700 0.700 0.700 f1 / f -4.748 -0.873 -1.924 f2 / f 0.407 0.341 0.336 f3 / f -1.133 -0.684 -2.750 f4 / f -11.850 -15.864 -1.170 TTL / f 1.658 1.706 1.732 f / θ(mm) 10.107 10.079 9.931 f / IH 0.865 0.863 0.848 f / EPD 7.557 7.535 7.424 SD1 / SD4 0.419 0.466 0.459 R1 / R2 1.292 3.599 1.586 R5 / R6 0.615 0.417 0.610 R7 / R8 0.785 0.768 0.344 R4 / f -0.341 -0.394 -0.197 R5 / f -0.205 -0.204 -0.151 R6 / f -0.334 -0.489 -0.247 R7 / f -0.666 -0.613 -0.443 R8 / f -0.848 -0.799 -1.287 R1 / R8 -0.640 -1.478 -0.335

[0109] In summary, the optical lens provided by the present invention has at least the following advantages:

[0110] (1) The object side of the first lens is convex, which helps to converge the incident light, reduce the aperture of the head lens, and facilitate the miniaturization of the head. The lens has telephoto characteristics, which can better present larger local details, making the image more focused and compact, thereby meeting the needs of local shooting; it can also realize the large image plane characteristics of the lens, and can carry a larger chip to achieve high-definition imaging.

[0111] (2) The lens has a small aperture. By using a large F-number and small aperture design, the lens can achieve a long depth of field while ensuring image quality, so that the image can be accurately captured even when the image moves over a long range.

[0112] (3) The glass-plastic hybrid structure is adopted, which enhances the light transmittance, optimizes the lens offset at different temperatures, and can have good thermal stability while meeting the requirements of high pixel count, and can reduce costs.

[0113] (4) By setting specific surface shapes and reasonable optical power distribution, the lens has the characteristics of high relative illumination, which can capture real images well and the captured images have uniform brightness, making subsequent image analysis and processing better.

[0114] 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.

[0115] 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 consisting of four lens pieces, characterized in that, In order from the object side to the imaging surface along the optical axis, successively comprises: a first lens with negative refractive power, the object side surface of which is convex, and the image side surface of which is concave; a second lens with positive refractive power, the image side surface of which is convex; a third lens with negative refractive power, the object side surface of which is concave, and the image side surface of which is convex; a fourth lens with negative refractive power, the object side surface of which is concave, and the image side surface of which is convex; wherein the effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 7<f / EPD<8.

2. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the maximum half field angle θ of the optical lens satisfy: 9mm / rad<f / θ<12mm / rad.

3. The optical lens of claim 1, wherein, The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5<TTL / f<1.

9.

4. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 0.2<f2 / f<0.

6.

5. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -3<f3 / f<-0.5; the object side surface curvature radius R5 of the third lens and the image side surface curvature radius R6 of the third lens satisfy: 0.2<R5 / R6<0.

8.

6. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -20<f4 / f<-1; the object side surface curvature radius R7 of the fourth lens and the image side surface curvature radius R8 of the fourth lens satisfy: 0.2<R7 / R8<0.

8.

7. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the image side surface curvature radius R4 of the second lens satisfy: -0.5<R4 / f<-0.

1.

8. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the object side surface curvature radius R5 of the third lens satisfy: -0.5<R5 / f<-0.05; the effective focal length f of the optical lens and the image side surface curvature radius R6 of the third lens satisfy: -0.8<R6 / f<-0.

1.

9. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the object side surface curvature radius R7 of the fourth lens satisfy: -1<R7 / f<-0.1; the effective focal length f of the optical lens and the image side surface curvature radius R8 of the fourth lens satisfy: -1.5<R8 / f<-0.

2.

10. The optical lens of claim 1, wherein, The mechanical clear aperture SD1 of the first lens and the mechanical clear aperture SD4 of the fourth lens satisfy: 0.35<SD1 / SD4<0.5; the object side surface curvature radius R1 of the first lens and the image side surface curvature radius R8 of the fourth lens satisfy: -2<R1 / R8<-0.2.

Images