An optical lens

Abstract

The embodiment of the present application discloses an optical lens. The optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along an optical axis from an object side to an image side; the optical power of the first lens to the seventh lens and the optical power of the optical lens satisfy a certain proportional relationship. The optical lens provided by the embodiment of the present application can realize a large-aperture miniaturized optical lens by using the optical power cooperation of each lens, and can correct the aberration of the lens by using the optical power cooperation of each lens, so as to ensure that the optical lens has high resolving power, has the characteristics of wide field of view, large aperture and large image surface, and can meet the use requirements under the temperature of-40 DEG C to 95 DEG C.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of automobile driving technology, and in particular to an optical lens. Background Art

[0002] With technological advancements, the automotive industry has undergone significant reforms, with advanced driver assistance systems and autonomous driving systems entering the mainstream. Advanced automotive technology attempts to teach cars to observe, think, and learn independently, and in-vehicle cameras are the "eyes" of these technologies. As automotive technology advances, so too have in-vehicle cameras.

[0003] At present, the requirements of assisted driving systems and autonomous driving systems for vehicle-mounted cameras are increasing accordingly. The mainstream requirements for optical lenses in vehicle-mounted cameras in the market have become large aperture, miniaturization, wide angle, etc. However, the vehicle-mounted lenses in existing technologies cannot have the above advantages at the same time and cannot meet the gradually increasing requirements of the automotive industry. Summary of the Invention

[0004] The present invention provides an optical lens that can achieve high-quality imaging of the optical lens or even the camera while meeting the requirements of large aperture, miniaturization and wide angle.

[0005] An embodiment of the present invention provides an optical lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens, which are arranged in sequence from the object side to the image side along an optical axis;

[0006] The optical power of the first lens is The optical power of the second lens is The optical power of the third lens is The optical power of the fourth lens is The optical power of the fifth lens is The optical power of the sixth lens is The optical power of the seventh lens is The optical power of the optical lens is The optical lens meets the following requirements:

[0007]

[0008]

[0009]

[0010]

[0011]

[0012]

[0013]

[0014] Optionally, the combined optical power of the first lens and the second lens is The optical lens meets the following requirements:

[0015] Optionally, the first lens, the second lens, and the sixth lens have negative optical power, and the third lens, the fourth lens, the fifth lens, and the seventh lens have positive optical power.

[0016] Optionally, the opposing surfaces of the fifth lens and the sixth lens are cemented to each other to form a cemented lens.

[0017] Optionally, the Abbe number of the fifth lens is v5, and the Abbe number of the sixth lens is v6;

[0018] The fifth lens and the sixth lens satisfy:

[0019] Optionally, the first lens, the third lens, the fifth lens, the sixth lens and the seventh lens are spherical lenses, and the second lens and the fourth lens are aspherical lenses.

[0020] Optionally, a refractive index Nd1 of the first lens satisfies: Nd1>1.75.

[0021] Optionally, the optical lens is an all-glass lens.

[0022] Optionally, a stop is further included, and the stop is located between the third lens and the fourth lens or between the fourth lens and the fifth lens.

[0023] The optical lens provided by the embodiment of the present invention comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence from the object side to the image side along the optical axis; the optical power of the first lens is The optical power of the second lens is The focal power of the third lens is The optical power of the fourth lens is The optical power of the fifth lens is The optical power of the sixth lens is The optical power of the seventh lens is The optical power of the optical lens is The optical lens satisfies the aforementioned focal power ratio relationship, and the focal power of each lens can be coordinated to achieve a large aperture and compact optical lens. The coordinated focal power of each lens can also be used to correct lens aberrations, ensuring that the optical lens has high resolution. The optical lens provided by the embodiments of the present invention can ensure the balance of the incident angles of the front and rear lens groups, and has the characteristics of a wide field of view, a large aperture, and a large image surface. While achieving good image quality, it can meet the operating requirements of temperatures between -40°C and 95°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a schematic structural diagram of an optical lens provided in Example 1 of the present invention;

[0025] Figure 2 yes Figure 1 The light fan diagram of the optical lens in the first embodiment is shown;

[0026] Figure 3 1 is a schematic structural diagram of an optical lens provided in Embodiment 2 of the present invention;

[0027] Figure 4 yes Figure 3 The light fan diagram of the optical lens in the second embodiment is shown;

[0028] Figure 5 This is a schematic structural diagram of an optical lens provided in Example 3 of the present invention;

[0029] Figure 6 yes Figure 5 The light fan diagram of the optical lens in the third embodiment is shown. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0031] The terms used in the embodiments of the present application are merely for the purpose of describing particular embodiments and are not intended to limit the present application. It should be noted that the positional words such as "upper", "lower", "left", "right", and the like described in the embodiments of the present application are described in the angle shown in the drawings, and should not be understood as a limitation on the embodiments of the present application. In addition, it should be understood in the context that when referring to an element being formed "on" or "under" another element, it can be formed "on" or "under" another element directly or indirectly through an intermediate element. The terms "first", "second", and the like are only for the purpose of description and do not represent any order, quantity, or importance, but are only used to distinguish different components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0032] Figure 1 is a structural schematic diagram of an optical lens provided by an embodiment of the present application, referring to Figure 1 The optical lens comprises, in order along the optical axis from the object side to the image side, a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16, and a seventh lens 17; the focal power of the first lens 11 is The focal power of the second lens 12 is The focal power of the third lens 13 is The focal power of the fourth lens 14 is The focal power of the fifth lens 15 is The focal power of the sixth lens 16 is The focal power of the seventh lens 17 is The focal power of the optical lens is The optical lens satisfies:

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040] Among them, the focal length of the lens is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, which represents the ability of the optical system to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the focal length, the weaker the ability to bend light. When the focal length is positive, the refraction of light is convergent; when the focal length is negative, the refraction of light is divergent. Figure 1 In the illustrated optical lens, the first lens 11, the second lens 12, and the seventh lens 17 are configured with negative focal powers, while the third lens 13, the fourth lens 14, the fifth lens 15, and the sixth lens 16 have positive focal powers. Each lens can be used to converge or diverge light. By properly setting the focal power ratios of each lens relative to the overall optical lens, the relative convergence or divergence of each lens within the overall lens is effectively limited. The aforementioned ratios of the focal powers of each lens to the focal power of the optical lens are derived through reasonable experimentation. Under these focal power ratios, the entire fixed-focus lens can correct and balance various aberrations, such as distortion and spherical aberration, ensuring image quality while meeting the requirements of a large aperture, miniaturization, and wide angle.

[0041] Exemplarily, the first lens 11 can be set as a convex-concave lens, the second lens 12 can be set as a biconcave lens, the third lens 13 can be set as a concave-convex lens, the fourth lens 14 can be set as a biconvex lens, the fifth lens 15 can be set as a biconvex lens, the sixth lens 16 can be set as a biconcave lens, and the seventh lens 17 can be set as a biconvex lens.

[0042] The optical lens provided by the embodiment of the present invention comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence from the object side to the image side along the optical axis; the optical power of the first lens is The optical power of the second lens is The focal power of the third lens is The optical power of the fourth lens is The optical power of the fifth lens is The optical power of the sixth lens is The optical power of the seventh lens is The optical power of the optical lens is The optical lens satisfies the aforementioned focal power ratio relationship, and the focal power of each lens can be coordinated to achieve a large aperture and compact optical lens. The coordinated focal power of each lens can also be used to correct lens aberrations, ensuring that the optical lens has high resolution. The optical lens provided by the embodiments of the present invention can ensure the balance of the incident angles of the front and rear lens groups, and has the characteristics of a wide field of view, a large aperture, and a large image surface. While achieving good image quality, it can meet the operating requirements of temperatures between -40°C and 95°C.

[0043] Furthermore, in the embodiment of the present invention, the combined optical power of the first lens 11 and the second lens 12 can be set to Optical lens meets:

[0044] In addition, each lens in the optical lens of the embodiment of the present invention can meet the following optical power conditions: the first lens 11, the second lens 12, and the sixth lens 16 have negative optical power, and the third lens 13, the fourth lens 14, the fifth lens 15 and the seventh lens 17 have positive optical power.

[0045] Among them, the first lens 11 and the second lens 12 are set to have negative optical power. While setting the optical power of the combined lens group of these two lenses to be negative, they are also set to meet the above-mentioned ratio with the entire optical lens. The two lenses can cooperate to control the incident angle of the optical system and ensure a large field of view. On this basis, through the cooperation of the positive and negative optical powers of other lenses, the aberrations of the optical lens with a large field of view can be corrected to ensure that the optical lens has a high resolving power.

[0046] Optionally, to improve the quality of aberration correction, the fifth lens 15 and the sixth lens 16 may be cemented together to form a cemented lens. Furthermore, in a specific embodiment, the Abbe number of the fifth lens 15 may be v5, and the Abbe number of the sixth lens 16 may be v6; and the fifth lens 15 and the sixth lens 16 may satisfy:

[0047] Those skilled in the art will appreciate that the fifth lens element 15 and the sixth lens element 16 are biconvex and biconcave, respectively. By appropriately modifying the surface shapes of the fifth and sixth lenses 15, 16, such as their radius of curvature and aspheric parameters, the curvatures of adjacent surfaces can be made consistent before bonding. This ensures that the fifth and sixth lenses 15, 16 achieve a coordinated positive and negative optical power, correcting aberrations such as field curvature. Furthermore, setting the Abbe number difference v5 - v6 of the bonded fifth and sixth lenses 15, 16 to be greater than 25 can help correct chromatic aberrations in the optical lens, resulting in clearer images.

[0048] Furthermore, the optical lens in this embodiment further includes an aperture 20, which is located in the optical path between the third lens 13 and the fourth lens 14. Of course, in other embodiments of the present invention, the aperture 20 may also be disposed in the optical path between the third lens 13 and the fifth lens 15.

[0049] The diaphragm 20 in an optical system limits the size of the light beam, determining the amount of light that passes through the lens and reaches the photosensitive element. This means it controls the amount of light passing through the lens, directly determining the size of the optical lens's aperture. In the optical lens provided by the present invention, the diaphragm is positioned between the third and fourth lenses, or between the fourth and fifth lenses, utilizing the waist position of the entire optical system to control light transmission. This effectively limits the size of the optical system's aperture while ensuring the amount of light that passes through the diaphragm, thus ensuring image brightness. Furthermore, the diaphragm blocks off-axis light, effectively reducing off-axis aberrations and ensuring image clarity.

[0050] In a specific embodiment, the first lens 11 , the third lens 13 , the fifth lens 15 , the sixth lens 16 , and the seventh lens 17 may be spherical lenses, and the second lens 12 and the fourth lens 14 may be aspherical lenses.

[0051] The fourth lens element 14 is configured as an aspheric lens and is positioned at the system aperture to primarily correct spherical aberration. The second lens element 12 is configured as an aspheric lens and positioned away from the aperture to effectively expand the optical system's field of view in conjunction with the first lens element 11 while also correcting off-axis aberrations of the optical system, including coma, astigmatism, and distortion.

[0052] Furthermore, in the embodiment of the present invention, the refractive index Nd1 of the first lens 11 may satisfy: Nd1>1.75. A lens refractive index greater than 1.75 indicates that the lens has relatively strong refractive power.

[0053] Taking into account the wide-angle requirement, the first lens 11, which is the first lens on the optical path of the optical lens, is generally set to a larger optical focal length to make the light bending ability stronger, gather more light, and increase the incident angle. That is, the curvature of the first lens 11 is set to be larger to achieve a large optical focal length. In other words, based on the large field of view of the lens, in order to ensure the incident angle of the light, the first lens and the first lens 11 need to meet R / F < 30, where R is the radius of curvature of the object side of the first lens 11, and F is the focal length of the optical lens. The smaller the R value, the more convex the object side shape of the first lens 11, and the more light enters from the outside. Based on this, in this embodiment, the first lens 11 is set to have a larger refractive index, and is greater than 1.75, which can increase the light refractive power of the lens and assist in achieving a wide angle. Conversely, under the premise of the same refractive power, using a lens with a larger refractive index can reduce the curvature of the lens, which can make the surface of the first lens 11 relatively flatter, thereby helping to reduce the processing difficulty of the lens and ensure the machinability of the lens.

[0054] Optionally, the optical lens in this embodiment of the present invention is an all-glass lens, that is, the first lens 11 to the seventh lens 17 are all made of glass. The main purpose of using glass lenses is to reduce the sensitivity of the lenses to temperature by using glass material, ensure the imaging quality of the lenses at different temperatures, meet the use requirements under temperature conditions of -40°C to 95°C, and be more suitable for the use scenario of vehicle-mounted lenses.

[0055] Based on the same inventive concept above, the present invention provides three different specific embodiments, whose optical power relationships and design ranges are shown in Table 1:

[0056] Table 1 Relationship and design range of the optical power of the optical lens in three embodiments of the present invention

[0057] like Figure 1 The parameter design values ​​of each lens in the optical lens of Example 1 are shown in Table 2:

[0058] Table 2 A design value of each lens of the optical lens

[0059] Surface number Face shape Curvature radius (mm) Thickness (mm) Refractive index Abbe number K value S1 spherical surface 24.68 1 1.8 46.5 S2 spherical surface 6.04 1.99 S3 Aspheric -16.61 0.99 1.81 40.7 7.07 S4 Aspheric 15.1 1.04 14.56 S5 spherical surface -30.57 4 1.95 18 S6 spherical surface -12.29 2.16 aperture spherical surface PL 0.1 S7 Aspheric 10.86 1.8 1.62 63.9 7.59 S8 Aspheric -6.84 0.1 -1.82 S9 spherical surface 11.55 2.76 1.73 54.7 S10 spherical surface -6.58 0.6 1.85 23.8 S11 spherical surface 6.36 2.06 S12 spherical surface 13.24 1.37 1.95 32.3 S13 spherical surface -33.05 1.5 S14 spherical surface PL 0.7 1.52 64.2 S15 spherical surface PL 2.45

[0060] The surface numbers in Table 2 are numbered according to the order of the surfaces of each lens, where "S1" represents the front surface of the first lens, "S2" represents the back surface of the first lens, and so on; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents that the surface is curved toward the image plane, and a negative value represents that the surface is curved toward the object plane, where "PL" represents that the surface is flat and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a blank space represents that the current position is air with a refractive index of 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light, and a blank space represents that the current position is air; the K value represents the numerical value of the best-fit conic coefficient of the aspheric surface.

[0061] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0062]

[0063] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the curvature radius; k is the fitting cone coefficient; AD is the coefficient of the 4th, 6th, 8th, and 10th order terms of the aspheric polynomial.

[0064] The even-order coefficients of the aspheric surfaces in the above embodiment are shown in Table 3:

[0065] Table 3 Aspheric surface parameters

[0066] Surface number A B C D S3 3.559E-04 6.060E-05 -3.363E-06 6.572E-08 S4 1.883E-03 1.030E-04 7.690E-07 1.339E-07 S7 -7.579E-04 -5.510E-05 -3.868E-07 4.570E-09 S8 1.438E-04 -2.702E-05 -1.185E-08 2.473E-07

[0067] Figure 2 yes Figure 1 The ray fan diagram of the optical lens in the first embodiment is shown. It can be seen from the ray fan diagram that the imaging range of different wavelengths (0.436μm, 0.486μm, 0.546μm, 0.587μm and 0.656μm) at different field angles is within ±50μm, ensuring that the aberration difference in different field areas is small, which means that the optical lens has better corrected the aberration of the optical system and has better imaging quality.

[0068] Figure 3 is a structural diagram of an optical lens provided by Example 2 of the present invention, Figure 3 The focal length relationship and refractive index design values ​​of the optical lens in the second embodiment are shown in Table 1. The design values ​​of a parameter of each lens in the optical lens are shown in Table 4:

[0069] Table 4 A design value of each lens of the optical lens

[0070]

[0071]

[0072] The surface numbers in Table 4 are numbered according to the order of the surfaces of each lens, where "S1" represents the front surface of the first lens, "S2" represents the back surface of the first lens, and so on; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents that the surface is curved toward the image plane, and a negative value represents that the surface is curved toward the object plane, where "PL" represents that the surface is flat and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a blank space represents that the current position is air with a refractive index of 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light, and a blank space represents that the current position is air; the K value represents the numerical value of the best-fit conic coefficient of the aspheric surface.

[0073] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0074]

[0075] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the curvature radius; k is the fitting cone coefficient; AD is the coefficient of the 4th, 6th, 8th, and 10th order terms of the aspheric polynomial.

[0076] The even-order coefficients of the aspheric surfaces in the above embodiment are shown in Table 5:

[0077] Table 5 Aspheric surface parameters

[0078] Surface number A B C D S3 -5.520E-04 1.736E-05 -5.131E-07 4.918E-08 S4 2.183E-04 1.489E-06 2.869E-06 -6.408E-08 S7 -5.805E-04 -3.680E-05 -8.626E-07 -3.462E-08 S8 7.498E-05 -3.410E-05 2.968E-06 -1.003E-07

[0079] Figure 4 yes Figure 3 The ray fan diagram of the optical lens in the second embodiment is shown. It can be seen from the ray fan diagram that the imaging range of different wavelengths (0.436μm, 0.486μm, 0.546μm, 0.587μm and 0.656μm) at different field angles is within ±50μm, ensuring that the aberration difference in different field areas is small, which means that the optical lens has better corrected the aberration of the optical system and has better imaging quality.

[0080] Figure 5 is a structural diagram of an optical lens provided by Example 3 of the present invention, Figure 5 The focal length relationship and refractive index design values ​​of the optical lens in the third embodiment are shown in Table 1.

[0081] The design values ​​of a parameter of each lens in the optical lens are shown in Table 6:

[0082] Table 6 A design value of each lens of the optical lens

[0083]

[0084]

[0085] The surface numbers in Table 6 are numbered according to the order of the surfaces of each lens, where "S1" represents the front surface of the first lens, "S2" represents the back surface of the first lens, and so on; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents that the surface is curved toward the image plane, and a negative value represents that the surface is curved toward the object plane, where "PL" represents that the surface is flat and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a blank space represents that the current position is air with a refractive index of 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to the light, and a blank space represents that the current position is air; the K value represents the numerical value of the best-fit conic coefficient of the aspheric surface.

[0086] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following expression method:

[0087]

[0088] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the curvature radius; k is the fitting cone coefficient; AD is the coefficient of the 4th, 6th, 8th, and 10th order terms of the aspheric polynomial.

[0089] The even-order coefficients of the aspheric surfaces in the above embodiment are shown in Table 7:

[0090] Table 7 Aspheric surface parameters

[0091] Surface number A B C D S3 -1.932E-04 -2.238E-06 4.042E-07 -6.295E-08 S4 9.872E-04 2.014E-06 5.167E-06 -4.754E-07 S7 1.439E-04 -1.848E-05 2.733E-06 -1.631E-07 S8 9.699E-04 7.228E-05 -4.887E-06 4.579E-07

[0092] Figure 6 yes Figure 5 The ray fan diagram of the optical lens in the third embodiment is shown. It can be seen from the ray fan diagram that the imaging range of different wavelengths (0.436μm, 0.486μm, 0.546μm, 0.587μm and 0.656μm) under different field angles is within ±50μm, ensuring that the aberration difference in different field areas is small, which means that the optical lens has better corrected the aberration of the optical system and has better imaging quality.

[0093] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations, and substitutions are possible for those skilled in the art without departing from the scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. An optical lens, characterized in that: The optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence from the object side to the image side along the optical axis; the optical lens has seven lenses; The focal power of the first lens is φ1, the focal power of the second lens is φ2, the focal power of the third lens is φ3, the focal power of the fourth lens is φ4, the focal power of the fifth lens is φ5, the focal power of the sixth lens is φ6, the focal power of the seventh lens is φ7, and the focal power of the optical lens is φ. The optical lens satisfies: -0.6<φ1 / φ<-0.25; -0.55<φ2 / φ<-0.1; 0.1<φ3 / φ<0.45; 0.3<φ4 / φ<0.65; 0.4<φ5 / φ<0.9; -1.4<φ6 / φ<-0.7; 0.2<φ7 / φ<0.5; The combined optical power of the first lens and the second lens is φ12, and the optical lens satisfies: -1.3<φ12 / φ<-0.5; The first lens, the second lens, and the sixth lens have negative refractive power, and the third lens, the fourth lens, the fifth lens, and the seventh lens have positive refractive power; The object side surface of the first lens is convex, and the image side surface is concave; The object side surface of the second lens is concave or convex, and the image side surface is concave; The object side surface of the third lens is concave or convex, and the image side surface is convex; The object-side surface of the fourth lens is convex, and the image-side surface is convex; The object-side surface of the fifth lens is convex, and the image-side surface is convex; The object-side surface of the sixth lens is concave, and the image-side surface is concave; The object-side surface of the seventh lens is convex, and the image-side surface is convex.

2. The optical lens according to claim 1, wherein: Opposite surfaces of the fifth lens and the sixth lens are cemented to each other to form a cemented lens.

3. The optical lens according to claim 2, wherein: The Abbe number of the fifth lens is v5, and the Abbe number of the sixth lens is v6; The fifth lens and the sixth lens satisfy the following conditions: -0.9<φ5 / φ6<-0.3, v5-v6>25.

4. The optical lens according to claim 1, wherein: The first lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are spherical lenses, and the second lens and the fourth lens are aspherical lenses.

5. The optical lens according to claim 1, wherein: The refractive index Nd1 of the first lens satisfies: Nd1>1.

75.

6. The optical lens according to claim 1, wherein: The optical lens is an all-glass lens.

7. The optical lens according to claim 1, wherein: The optical system further includes a stop located between the third lens and the fourth lens or between the fourth lens and the fifth lens.

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