Optical lens

Abstract

The optical lens comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object plane to an image plane along an optical axis, the first lens is a glass aspheric lens with negative focal power; the second lens is a glass spherical lens with positive focal power; the third lens is a glass spherical lens with positive focal power; the fourth lens is a glass spherical lens with positive focal power; the fifth lens is a glass spherical lens with negative focal power; the six-lens structure is adopted, the shape and the focal power of each lens and the relative position of each lens are optimized, so that the optical lens with the characteristics of large aperture, high definition, small size, no large deviation of resolution at high and low temperatures and the like is realized, and the market demand of the vehicle-mounted camera lens is met.

Description

Technical Field

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

[0002] With the rapid development of the automotive industry and the continuous improvement of its intelligence, people are paying more and more attention to driving safety, and various assisted driving functions have emerged. As a key component of ADAS (Advanced Driver Assistance Systems), vehicle-mounted camera lenses can sense the conditions around the vehicle in real time and realize functions such as forward collision warning, lane departure warning and pedestrian detection. Their performance directly affects the safety factor of ADAS. Therefore, the performance requirements for vehicle-mounted camera lenses are getting higher and higher.

[0003] Currently, conventional automotive lenses have performance defects such as low resolution and large size, which cannot meet market demand. Therefore, it is necessary to develop an optical lens with high resolution and small size. Summary of the invention

[0004] The present invention provides an optical lens, which adopts 6 lenses and realizes the optical lens with the characteristics of large aperture, high definition, small size, and no large deviation of resolution under high and low temperatures by optimizing the shape, optical focal length and relative position of each lens, so as to meet the market demand for vehicle-mounted camera lenses.

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

[0006] The first lens is a glass aspherical lens with negative optical power; the second lens is a glass spherical lens with positive optical power; the third lens is a glass spherical lens with positive optical power; the fourth lens is a glass spherical lens with positive optical power; the fifth lens is a glass spherical lens with negative optical power; and the sixth lens is a glass spherical lens with positive optical power.

[0007] Optionally, along the direction from the object plane to the image plane of the optical axis, the object side surface of the first lens is convex, and the image side surface is concave, the object side surface and the image side surface of the second lens are convex, the object side surface and the image side surface of the third lens are convex, the object side surface and the image side surface of the fourth lens are convex, the object side surface of the fifth lens is concave, and the object side surface of the sixth lens is convex.

[0008] Optionally, the fourth lens and the fifth lens are cemented to form a cemented lens.

[0009] Optionally, the optical power of the first lens to the sixth lens meets the following conditions:

[0010]

[0011]

[0012]

[0013] in, is the focal length of the optical lens, The optical powers of the first lens to the sixth lens are represented in sequence.

[0014] Optionally, the refractive index and Abbe number of the first lens to the sixth lens satisfy the following conditions:

[0015] 1.75≤n1≤1.87;38.5≤v1≤50.5;

[0016] 1.58≤n2≤1.94;33.5≤v2≤41.5;

[0017] 1.63≤n3≤1.84;44.5≤v3≤59.9;

[0018] 1.55≤n4≤1.64;60.5≤v4≤72.5;

[0019] 1.76≤n5≤1.97;17.3≤v5≤27.2;

[0020] 1.73≤n6≤1.98;30.5≤v6≤51.5;

[0021] Among them, n1, n2, n3, n4, n5, and n6 represent the refractive indices of the first lens to the sixth lens in sequence, respectively, and v1, v2, v3, v4, v5, and v6 represent the Abbe numbers of the first lens to the sixth lens in sequence.

[0022] Optionally, the effective focal length EFFL of the optical lens satisfies the following relation with the total optical length TTL of the optical lens:

[0023] TTL / EFFL<5.5.

[0024] Optionally, an entrance pupil diameter ENPD of the optical lens and a total optical length TTL of the optical lens satisfy: ENPD / TTL>0.1.

[0025] Optionally, a central curvature radius R1 of the object side of the first lens and an effective focal length EFFL of the lens satisfy: 0.8<R1 / EFFL<1.5.

[0026] Optionally, the Abbe number Vd4 and the refractive index Nd4 of the fourth lens and the Abbe number Vd5 and the refractive index Nd5 of the fifth lens satisfy:

[0027] 2.5<Vd4 / Vd5<3.6; 0.8<Nd4 / Nd5<0.9.

[0028] Optionally, the optical back focus BFL of the optical lens and the total optical length TTL of the optical lens satisfy: BFL / TTL≥0.11.

[0029] Optionally, a stop is also included, and the stop is located between the second lens and the third lens.

[0030] The optical lens provided by an embodiment of the present invention includes 6 lenses arranged in sequence from the object plane to the image plane along the optical axis, and the optical powers of the 6 lenses are negative, positive, positive, positive, negative, and positive, respectively. By optimizing the shape, optical power and relative position of each lens, an optical lens with the characteristics of large aperture, high definition, small size, and no large deviation in resolution under high and low temperatures is realized, thereby meeting the market demand for vehicle-mounted camera lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the structure of an optical lens provided in the first embodiment of the application;

[0032] Figure 2 A light fan diagram of an optical lens provided in the first embodiment of the application;

[0033] Figure 3 An axial aberration diagram of an optical lens provided in the first embodiment of the application;

[0034] Figure 4 A structural diagram of an optical lens provided for application embodiment 2;

[0035] Figure 5 A light fan diagram of an optical lens provided in the second embodiment of the application;

[0036] Figure 6 An axial aberration diagram of an optical lens provided in the second embodiment of the application;

[0037] Figure 7 A structural diagram of an optical lens provided for application embodiment 3;

[0038] Figure 8 A light fan diagram of an optical lens provided in the third embodiment of the application;

[0039] Fig. 9 This is an axial aberration diagram of an optical lens provided in application embodiment 3. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0041] Figure 1 A schematic diagram of the structure of an optical lens provided in the first embodiment of the application, referring to Figure 1 An optical lens provided by an embodiment of the present invention includes a lens along an optical axis ( Figure 1 From the object plane ( Figure 1 A first lens L1, a second lens L2, a stop STO, a third lens L3, a fourth lens L4, a fifth lens L5 and a sixth lens L6 are arranged in sequence from the image plane IMA to the image plane IMA (not shown);

[0042] The first lens L1 is a glass aspherical lens with negative power; the second lens L2 is a glass spherical lens with positive power, the third lens L3 is a glass spherical lens with positive power, the fourth lens L4 is a glass spherical lens with positive power, the fifth lens L5 is a glass spherical lens with negative power, and the sixth lens L6 is a glass spherical lens with positive power.

[0043] refer to Figure 1 In the embodiment of the present application, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L5 can be arranged in sequence along the optical axis from the object plane to the image plane in a lens barrel ( Figure 1 It should be noted that Figure 1 The structural schematic diagrams corresponding to the subsequent embodiments are only schematic diagrams of the structures, and the shapes such as aspherical surfaces are not represented according to the actual situation.

[0044] Among them, the focal length is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam. Its value is the reciprocal of the focal length, and it characterizes the ability of the optical lens 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 a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The focal length can be used to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group).

[0045] The aperture OTS includes an aperture diaphragm and a field diaphragm. The aperture diaphragm refers to the diaphragm that limits the light beam the most, and the field diaphragm refers to the diaphragm that limits the field of view (size) the most.

[0046] The front end of the aperture STO uses a first lens L1 with negative optical focal length and a second lens L2 with positive optical focal length. The first lens L1 diverges the incident light, and the second lens L2 converges the light. By reasonably matching the optical focal lengths of the first lens L1 and the second lens L2, the light can have a larger light aperture before entering the aperture STO, thereby increasing the aperture number of the optical lens and meeting the usage requirements under different conditions.

[0047] The aperture STO is set between the second lens L2 with positive focal power and the third lens L3 with positive focal power, which can adjust the propagation direction of the light beam emitted by the second lens L2 to the incident surface of the third lens L3, and limit the light beam or field of view in the optical lens. At the same time, the second lens L2 used at the front end of the aperture STO converges the light, which can avoid stray light such as reflection at the position of the aperture STO, and can adjust the aberration of the lens to a certain extent, ensuring the aberration balance of the lens and the stability of high and low temperature performance.

[0048] The rear end of the aperture STO uses a third lens L3 with positive focal power, a fourth lens L4 with positive focal power, a fifth lens L5 with negative focal power, and a sixth lens L6 with positive focal power. The third lens L3 and the fourth lens L4 converge the light along the optical axis, which can compress the beam aperture, limit the propagation angle and propagation direction of the light, and thus adjust the incident angle of the light entering the fifth lens L5. Furthermore, the fifth lens L5 and the sixth lens L6 are used in combination, first expanding the converged light and then converging it, which can correct the aberration at the rear end of the lens, which is conducive to forming a clear image on the image plane IMA and stabilizing the imaging quality of the optical lens.

[0049] Considering that glass lenses have a strong light deflection ability and a good correction effect on lens aberrations, the present application sets the first lens L1 to be a glass aspherical lens, and the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are all glass spherical lenses, which helps to reduce the number of lenses and the size of the lens. It can also enable the optical lens to have good resolution in the high and low temperature range, meeting the application requirements of vehicle-mounted lens performance.

[0050] For example, it can still maintain good performance in the ambient temperature range of -40 to 95°C.

[0051] It should be noted that the materials of the glass spherical lens and the glass aspherical lens are various types of glass known to those skilled in the art, and the embodiments of the present application will not elaborate on this and will not limit this.

[0052] Among them, considering that the aspherical lens has a good ability to control the high-order aberrations of the optical system, in the embodiment of the present application, the aspherical lens of the optical lens satisfies the following formula:

[0053]

[0054] Among them, z represents the axial vector height of the aspheric surface in the Z direction; r represents the distance from the point on the aspheric surface to the optical axis; c represents the curvature of the fitted sphere, which is the inverse of the radius of curvature; k represents the fitted cone coefficient; A, B, C, D, E, F, and G represent the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order coefficients of the aspheric polynomial, respectively.

[0055] Based on the above embodiments, Figure 1 , along the direction from the object side to the image side of the optical axis, the surface of the lens close to the object plane is the object side, and the surface of the lens close to the image plane is the image side.

[0056] The object side surface of the first lens L1 is convex, and the image side surface is concave. The object side surface and the image side surface of the second lens L2 are both convex. The object side surface and the image side surface of the third lens L3 are both convex. The object side surface and the image side surface of the fourth lens L4 are both convex. The object side surface of the fifth lens L5 is concave. The object side surface of the sixth lens L6 is convex.

[0057] refer to Figure 1 The surface type of the first lens L1 is convex-concave, the surface type of the second lens L2 is convex-convex, the surface type of the third lens L3 is convex-convex, and the surface type of the fourth lens L4 is convex-convex.

[0058] Among them, the concave lens has a divergent effect on the transmitted light, and the convex lens has a converging effect on the transmitted light. By reasonably setting the surface shapes of the first lens L1 to the sixth lens L6, clear imaging of the optical lens at various focal lengths can be achieved.

[0059] Based on the above embodiments, Figure 1 , the refractive powers of the first lens L1 to the sixth lens L6 satisfy the following conditions:

[0060]

[0061]

[0062]

[0063] in, is the focal length of the optical lens, The optical powers of the first lens L1 to the sixth lens L6 are represented in order.

[0064] Specifically, by reasonably matching the optical powers of the first lens L1 to the sixth lens L6, the aberration of the entire lens can be corrected, a clear image can be formed on the image plane IMA, and the imaging quality of the optical lens can be stabilized.

[0065] Based on the above embodiments, Figure 1 The fourth lens L4 and the fifth lens L5 are cemented to form a cemented lens, which can effectively reduce the air space between the fourth lens L4 and the fifth lens L5, reduce the total length of the optical lens, and help to eliminate chromatic aberration.

[0066] Based on the above embodiments, Figure 1 , the refractive index and Abbe number of the first lens L1 to the sixth lens L6 satisfy the following conditions:

[0067] 1.75≤n1≤1.87; 38.5≤v1≤50.5; 1.58≤n2≤1.94; 33.5≤v2≤41.5;

[0068] 1.63≤n3≤1.84; 44.5≤v3≤59.9; 1.55≤n4≤1.64; 60.5≤v4≤72.5;

[0069] 1.76≤n5≤1.97; 17.3≤v5≤27.2; 1.73≤n6≤1.98; 30.5≤v6≤51.5.

[0070] Among them, n1, n2, n3, n4, n5, and n6 represent the refractive indices of the first lens L1 to the sixth lens L6 in sequence, respectively, and v1, v2, v3, v4, v5, and v6 represent the Abbe numbers of the first lens L1 to the sixth lens L6 in sequence.

[0071] Among them, the refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. It is mainly used to describe the material's ability to refract light. Different materials have different refractive indices. The higher the refractive index, the slower the light propagates in the material. The Abbe number is an index used to represent the dispersion ability of a transparent medium, also known as the dispersion coefficient. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the milder the dispersion of the medium, the larger the Abbe number.

[0072] Generally speaking, the refractive index and the Abbe number are inversely proportional. This means that materials with higher refractive indexes tend to have lower Abbe numbers, and vice versa. In the optical design of the embodiment of the present application, by reasonably designing the refractive index and Abbe number of the first lens L1 to the sixth lens L6, and selecting a combination of materials with different refractive indices and Abbe numbers, it is helpful to improve the imaging effect of the optical lens while minimizing chromatic aberration.

[0073] The present application adopts 6 glass lenses, the first lens L1 is a glass aspherical lens, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are all glass spherical lenses. Compared with plastic lenses, by selecting glass lenses with higher refractive index, the refractive ability of the lens to light can be effectively increased. At the same time, the refractive index and Abbe number of the glass lens have a wide range of choices. By reasonably matching the refractive index and Abbe number of the first lens L1 to the sixth lens L6, the chromatic aberration of the optical lens can be corrected to a large extent, which is conducive to the combination of each lens to form an approximate bonding effect, thereby playing a role in achromatization.

[0074] Based on the above embodiments, Figure 1 , by reasonably setting the Abbe number Vd4, refractive index Nd4 of the fourth lens L4 and the Abbe number Vd5, refractive index Nd5 of the fifth lens L5 to satisfy:

[0075] 2.5<Vd4 / Vd5<3.6;0.8<Nd4 / Nd5<0.9. Such an arrangement is conducive to the bonding of the fourth lens L4 and the fifth lens L5, and eliminates the chromatic aberration of the light after passing through the two lenses.

[0076] Based on the above embodiments, Figure 1 The central curvature radius R1 of the object side surface of the first lens L1 and the effective focal length EFFL (Effective Focal Length, referred to as EFFL) of the optical lens satisfy: 0.8<R1 / EFFL<1.5.

[0077] Among them, the ratio between the radius of curvature of the lens and the focal length directly affects the imaging effect and optical performance of the lens. For focal length changes: when the radius of curvature of the lens increases, its focal length will also increase. In other words, since the increase in the radius of curvature means that the curvature of the lens decreases, the degree of refraction of light inside the lens decreases, resulting in an increase in focal length. As for imaging quality: changes in the radius of curvature will also affect the imaging quality of the lens. A smaller radius of curvature will lead to a stronger divergence or convergence of light, which will affect the clarity and contrast of the image. Based on this, the present application controls the ratio of the central radius of curvature R1 of the object side of the first lens L1 to the effective focal length EFFL of the optical lens to be between 0.8 and 1.5, which is beneficial to improving the imaging quality of the optical lens and controlling the volume of the optical lens within a reasonable range, thereby achieving the purpose of small volume.

[0078] Based on the above embodiments, Figure 1 , the effective focal length EFFL of the optical lens and the total optical length TTL (Total Track Length, referred to as TTL) of the optical lens satisfy: TTL / EFFL<5.5.

[0079] Among them, the total optical length TTL and effective focal length EFFL of the optical lens directly affect the imaging effect and applicable scenarios of the lens. The total optical length TTL of the optical lens refers to the distance from the object side of the first lens L1 in the lens to the image plane. The effective focal length EFFL refers to the distance from the optical center (principal point) of the optical lens to the imaging plane (focus). The longer the effective focal length EFFL, the more distant objects can be magnified and imaged; the shorter the effective focal length EFFL, the wider the shooting range. For the imaging effect, the relationship between the total optical length TTL and the effective focal length EFFL of the optical lens directly affects the imaging effect of the lens. The longer the effective focal length EFFL, the narrower the imaging range, but farther objects can be photographed; the shorter the effective focal length EFFL, the wider the imaging range, but the shooting distance is closer. For applicable scenarios: long focal length lenses are suitable for shooting distant objects or scenes that need to magnify details, such as telescopes, telephoto cameras, etc.; short focal length lenses are suitable for shooting wide scenes or scenes that require a wide range of vision, such as landscape photography, surveillance cameras, etc. The present application satisfies the ratio of the total optical length TTL of the optical lens to the effective focal length EFFL by reasonably controlling the following conditions: TTL / EFFL<5.5. Thus, the scene application requirements of the vehicle-mounted camera lens are met while ensuring high-quality imaging.

[0080] Based on the above embodiments, Figure 1 , the entrance pupil diameter ENPD (Entrance Pupil Diameter, referred to as ENPD) of the optical lens and the total optical length TTL of the optical lens satisfy: ENPD / TTL>0.1.

[0081] Among them, the entrance pupil refers to the equivalent aperture formed after the light enters the optical system and is refracted or reflected. The entrance pupil diameter determines how much light the optical system can collect, which directly affects the brightness and resolution of the image. The present application reasonably controls the ratio of the entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens to be greater than 0.1, thereby controlling the beam aperture of the incident light, increasing the field of view angle and the amount of light entering the optical lens, effectively compressing the volume of the optical lens, realizing the miniaturization of the lens, and at the same time improving the brightness and resolution of the image to meet the market demand for vehicle-mounted camera lenses.

[0082] Based on the above embodiments, Figure 1 , the optical back focus BFL (Back Focal Length, referred to as BFL) of the optical lens and the optical total length TTL of the optical lens satisfy: BFL / TTL≥0.11.

[0083] Among them, the optical back focus BFL of the optical lens refers to the distance from the last side of the lens in the optical lens to the image plane along the optical axis, that is, the distance from the image side of the sixth lens L6 to the image plane IMA in this application. The optical back focus BFL directly affects the final imaging quality of the optical lens and the space requirements for system installation. By reasonably setting the ratio between the optical back focus BFL of the optical lens and the total optical length TTL to at least 0.11, the installation requirements of the vehicle-mounted camera lens can be met, that is, the application requirements of small volume can be met.

[0084] On the basis of the above embodiment, the optical lens may further include a flat glass CG, which is arranged in the optical path between the sixth lens L6 and the image plane IMA, and the flat glass CG may protect the photosensitive chip in the imaging sensor. The imaging chip is used to convert the light signal collected by the optical lens into an electrical signal, thereby ensuring the imaging effect of the optical lens.

[0085] Reference Figure 1 As shown, each lens of the optical lens provided in the embodiment of the present application can be fixed in a lens barrel and sealed or vacuum packaged to ensure the stability and clarity of the mirror surface of each lens and to ensure the imaging quality, which is not shown in the embodiment of the present application.

[0086] In summary, the optical lens provided in the embodiment of the present invention adopts a 6-lens structure and realizes an optical lens with the characteristics of large aperture, high definition, small size, and no large deviation in resolution under high and low temperatures by optimizing the shape, optical focal length and relative position of each lens, thereby meeting the market demand for vehicle-mounted camera lenses.

[0087] Specific embodiments of the optical lens applicable to the above-mentioned embodiments are further described below with reference to the accompanying drawings.

[0088] Embodiment 1

[0089] Continue to refer Figure 1 , an optical lens provided in the first embodiment of the present invention includes a Figure 1 From the object plane ( Figure 1The first lens L1, the second lens L2, the aperture STO, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are arranged in sequence from the sixth lens L6 to the image plane IMA (not shown in the figure). The first lens L1 is a glass aspherical lens with negative focal power; the second lens L2 is a glass spherical lens with positive focal power, the third lens L3 is a glass spherical lens with positive focal power, the fourth lens L4 is a glass spherical lens with positive focal power; the fifth lens L5 is a glass spherical lens with negative focal power; and the sixth lens L6 is a glass spherical lens with positive focal power. The plane glass CG is arranged between the sixth lens L6 and the image plane IMA. The plane glass CG can protect the photosensitive chip in the imaging sensor, wherein the imaging chip is used to convert the light signal collected by the optical lens into an electrical signal, thereby ensuring the imaging effect of the optical lens.

[0090] refer to Figure 1 , the effective focal length EFFL of the optical lens is 4.39 mm, the aperture F number is 1.58, and the total optical length TTL of the optical lens is 23.34 mm. Table 1 details the specific optical physical parameters of each lens in the optical lens provided in Example 1 of the present invention.

[0091] Table 1 Design values ​​of optical physical parameters of optical lenses

[0092] Surface number S Surface type Curvature radius R thickness Materials (n.d.) Material (vd) S1 Aspheric 5.67 3.50 1.77 49.00 S2 Aspheric 1.87 1.85 S3 Spherical 16.93 5.50 1.88 40.00 S4 Spherical -16.93 -0.05 Aperture Spherical Infinity 1.22 S6 Spherical 9.25 2.79 1.65 58.40 S7 Spherical -9.25 0.11 S8 Spherical 10.90 2.00 1.60 68.00 S9 Spherical -4.26 1.64 1.78 25.72 S10 Spherical 30.15 0.16 S11 Spherical 9.14 1.78 1.88 40.13 S12 Spherical 59.40 0.64 S13 flat Infinity 0.60 1.52 64.20 S14 flat Infinity 1.61 S15 Image plane Infinity

[0093] Among them, the surface number S in Table 1 is numbered according to the surface order of each lens; "STO" represents the aperture of the optical lens; IMA represents the image plane; the radius of curvature R represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image plane, and a negative value represents that the surface is bent toward the object plane; "Infinity" represents that the surface is a plane 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 nd represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1. The Abbe number vd represents the dispersion characteristics of the material between the current surface and the next surface to the light; the half-aperture represents half of the lens aperture. Among them, the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number.

[0094] In this embodiment, the aspherical lens of the optical lens can satisfy the following formula:

[0095]

[0096] Among them, z represents the axial vector height of the aspheric surface in the Z direction; r represents the distance from the point on the aspheric surface to the optical axis; c represents the curvature of the fitted sphere, which is the inverse of the radius of curvature; k represents the fitted cone coefficient; A, B, C, D, E, F, and G represent the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order coefficients of the aspheric polynomial, respectively.

[0097] Exemplarily, Table 2 describes in detail the aspheric coefficients of each lens in the first embodiment in a feasible implementation manner.

[0098] Table 2 Design values ​​of aspheric coefficients of each lens in the optical lens

[0099] Surface number k A B C D E F S1 -5.49E+00 1.38E-03 -2.29E-04 5.59E-06 9.63E-08 -6.15E-09 7.52E-11 S2 -9.34E-01 -6.12E-03 -4.92E-04 -3.20E-05 2.51E-05 -2.74E-06 9.84E-08

[0100] Among them, 1.38E-03 means that the coefficient A of the surface number S1 is 1.38*10-3, and so on.

[0101] Furthermore, a number of performance tests were conducted on the optical lens provided in Example 1, and the test results are as follows:

[0102] Figure 2 A light fan diagram of an optical lens is provided for application Example 1, wherein the light fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis in the light fan diagram is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 2 It can be seen that the optical lens provided in Example 1 of the present application is well close to the horizontal axis at each wavelength in each field of view, indicating that the vertical axis aberration of each wavelength of the optical lens is well corrected. At the same time, there is no obvious dispersion of each wavelength from the wavelength of 0.436μm to 0.656nm, indicating that the system chromatic aberration is also well corrected, thereby ensuring that the optical lens can achieve high-resolution imaging requirements.

[0103] Figure 3 This is an axial aberration diagram of an optical lens provided in the first embodiment of the application. Figure 3 , the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Figure 3 It can be seen that from the wavelength of 0.436μm to 0.656nm, the axial aberration of normalized apertures at different wavelengths is controlled within a reasonable range, indicating that the axial chromatic aberration of the optical lens is well controlled and meets the usage requirements.

[0104] Embodiment 2

[0105] Figure 4 A structural diagram of an optical lens provided in the second embodiment of the application, refer to Figure 4 , an optical lens provided in the first embodiment of the present invention includes a Figure 4 From the object plane ( Figure 4 The first lens L1, the second lens L2, the aperture STO, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are arranged in sequence from the sixth lens L6 to the image plane IMA (not shown in the figure). The first lens L1 is a glass aspherical lens with negative focal power; the second lens L2 is a glass spherical lens with positive focal power, the third lens L3 is a glass spherical lens with positive focal power, the fourth lens L4 is a glass spherical lens with positive focal power; the fifth lens L5 is a glass spherical lens with negative focal power; and the sixth lens L6 is a glass spherical lens with positive focal power. The plane glass CG is arranged between the sixth lens L6 and the image plane IMA. The plane glass CG can protect the photosensitive chip in the imaging sensor, wherein the imaging chip is used to convert the light signal collected by the optical lens into an electrical signal, thereby ensuring the imaging effect of the optical lens.

[0106] refer to Figure 4 , the effective focal length EFFL of the optical lens is 4.44 mm, the aperture F number is 1.61, and the total optical length TTL of the optical lens is 23.34 mm. Table 3 details the specific optical physical parameters of each lens in the optical lens provided in the second embodiment of the present invention.

[0107] Table 3 Design values ​​of optical physical parameters of optical lenses

[0108] Surface number S Surface type Curvature radius R thickness Materials (n.d.) Material (vd) S1 Aspheric 5.36 3.38 1.85 40.00 S2 Aspheric 1.94 1.70 S3 Spherical 25.00 5.46 1.60 38.00 S4 Spherical -25.00 0.05 Aperture Spherical Infinity 0.10 S6 Spherical 8.60 3.56 1.82 46.00 S7 Spherical -11.74 0.52 S8 Spherical 8.63 2.46 1.57 70.99 S9 Spherical -3.71 0.80 1.81 23.00 S10 Spherical 23.71 0.20 S11 Aspheric 9.31 2.32 1.96 32.00 S12 Aspheric -55.00 0.64 S13 flat Infinity 0.60 1.52 64.20 S14 flat Infinity 1.55 S15 Image plane Infinity

[0109] Among them, the surface number S in Table 3 is numbered according to the surface order of each lens; the radius of curvature R represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "Infinity" means that the surface is a plane 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 nd represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1. The Abbe number vd represents the dispersion characteristics of the material between the current surface and the next surface to the light; the half-aperture represents half of the lens aperture. Among them, the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number.

[0110] In this embodiment, the aspherical lens of the optical lens can satisfy the following formula:

[0111]

[0112] Among them, z represents the axial vector height of the aspheric surface in the Z direction; r represents the distance from the point on the aspheric surface to the optical axis; c represents the curvature of the fitted sphere, which is the inverse of the radius of curvature; k represents the fitted cone coefficient; A, B, C, D, E, F, and G represent the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order coefficients of the aspheric polynomial, respectively.

[0113] Exemplarily, Table 4 describes in detail the aspheric coefficients of each lens in Example 2 of the present application in a feasible implementation manner.

[0114] Table 4 Design values ​​of aspheric coefficients of each lens in the optical lens

[0115] Surface number k A B C D E F S1 -3.61E+00 9.62E-04 -1.49E-04 6.47E-07 1.76E-07 -4.10E-09 1.55E-11 S2 -8.59E-01 -4.52E-03 -1.56E-03 2.94E-04 -3.92E-05 3.68E-06 -1.53E-07

[0116] Among them, 9.62E-04 means that the coefficient A of the surface number S1 is 9.62*10-4, and so on.

[0117] Furthermore, the performance parameters of the optical lens provided in Example 2 were tested, and the test results are as follows:

[0118] Figure 5 A light fan diagram of an optical lens provided in the second embodiment of the application, referring to Figure 5 The horizontal axis of the light fan diagram is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane. The corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 5 It can be seen that the optical lens provided in Example 2 of the present application is well aligned with the horizontal coordinate at each wavelength in each field of view, indicating that the vertical axis aberration of each wavelength of the optical lens is well corrected. At the same time, there is no obvious dispersion of each wavelength from the wavelength of 0.436μm to 0.656nm, indicating that the system chromatic aberration is also well corrected, thereby ensuring that the optical lens can achieve high-resolution imaging requirements.

[0119] Figure 6 Axial aberration diagram of an optical lens provided in the second embodiment of the application. Figure 6 , the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Figure 6It can be seen that from the wavelength of 0.436μm to 0.656nm, the axial aberration of normalized apertures at different wavelengths is controlled within a reasonable range, indicating that the axial chromatic aberration of the optical lens is well controlled and meets the usage requirements.

[0120] Embodiment 3

[0121] Figure 7 A structural diagram of an optical lens provided in the second embodiment of the application, refer to Figure 7 , an optical lens provided in the first embodiment of the present invention includes a Figure 7 From the object plane ( Figure 7 The first lens L1, the second lens L2, the aperture STO, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are arranged in sequence from the sixth lens L6 to the image plane IMA (not shown in the figure). The first lens L1 is a glass aspherical lens with negative focal power; the second lens L2 is a glass spherical lens with positive focal power, the third lens L3 is a glass spherical lens with positive focal power, the fourth lens L4 is a glass spherical lens with positive focal power; the fifth lens L5 is a glass spherical lens with negative focal power; and the sixth lens L6 is a glass spherical lens with positive focal power. The plane glass CG is arranged between the sixth lens L6 and the image plane IMA. The plane glass CG can protect the photosensitive chip in the imaging sensor, wherein the imaging chip is used to convert the light signal collected by the optical lens into an electrical signal, thereby ensuring the imaging effect of the optical lens.

[0122] refer to Figure 7 , the effective focal length EFFL of the optical lens is 4.45 mm, the aperture F number is 1.42, and the total optical length TTL of the optical lens is 23.26 mm. Table 5 details the specific optical physical parameters of each lens in the optical lens provided in the third embodiment of the present invention.

[0123] Table 5 Design values ​​of optical physical parameters of optical lenses

[0124]

[0125]

[0126] Among them, the surface number S in Table 5 is numbered according to the surface order of each lens; the radius of curvature R represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "Infinity" means that the surface is a plane 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 nd represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1. The Abbe number vd represents the dispersion characteristics of the material between the current surface and the next surface to the light; the half-aperture represents half of the lens aperture. Among them, the more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, the larger the Abbe number.

[0127] In this embodiment, the aspherical lens of the optical lens can satisfy the following formula:

[0128]

[0129] Among them, z represents the axial vector height of the aspheric surface in the Z direction; r represents the distance from the point on the aspheric surface to the optical axis; c represents the curvature of the fitted sphere, which is the inverse of the radius of curvature; k represents the fitted cone coefficient; A, B, C, D, E, F, and G represent the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order coefficients of the aspheric polynomial, respectively.

[0130] Exemplarily, Table 6 describes in detail the aspheric coefficients of each lens in Example 3 of the present application in a feasible implementation manner.

[0131] Table 6 Design values ​​of aspheric coefficients of each lens in the optical lens

[0132]

[0133]

[0134] Among them, 3.64E-03 means that the coefficient A of the surface number S1 is 3.64*10 -3 , and so on.

[0135] Furthermore, the performance parameters of the optical lens provided in Example 3 were tested, and the test results are as follows:

[0136] Figure 7 A light fan diagram of an optical lens provided in the third embodiment of the application, referring to Figure 7The horizontal axis of the light fan diagram is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane. The corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 7 It can be seen that the optical lens provided in Example 2 of the present application is well aligned with the horizontal coordinate at each wavelength in each field of view, indicating that the vertical axis aberration of each wavelength of the optical lens is well corrected. At the same time, there is no obvious dispersion of each wavelength from the wavelength of 0.436μm to 0.656nm, indicating that the system chromatic aberration is also well corrected, thereby ensuring that the optical lens can achieve high-resolution imaging requirements.

[0137] Figure 8 This is an axial aberration diagram of an optical lens provided in the third embodiment of the application. Figure 8 , the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius; the horizontal direction represents the offset relative to the main wavelength, in millimeters (mm). Figure 8 It can be seen that from the wavelength of 0.436μm to 0.656nm, the axial aberration of normalized apertures at different wavelengths is controlled within a reasonable range, indicating that the axial chromatic aberration of the optical lens is well controlled and meets the usage requirements.

[0138] In summary, in Embodiment 1, Embodiment 2 and Embodiment 3 of the present application, the optical physical parameters of the first lens to the sixth lens are as shown in Table 7.

[0139] Table 7 Design values ​​of optical physical parameters of optical lenses

[0140]

[0141]

[0142] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An optical lens, characterized in that: It includes a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens and a sixth lens which are arranged in sequence from the object plane to the image plane along the optical axis; The first lens is a glass aspherical lens with negative optical power; the second lens is a glass spherical lens with positive optical power; the third lens is a glass spherical lens with positive optical power; the fourth lens is a glass spherical lens with positive optical power; the fifth lens is a glass spherical lens with negative optical power; and the sixth lens is a glass spherical lens with positive optical power.

2. The optical lens according to claim 1, characterized in that: Along the direction from the object plane to the image plane, The object side surface of the first lens is convex, and the image side surface is concave, the object side surface and the image side surface of the second lens are convex, the object side surface and the image side surface of the third lens are convex, the object side surface and the image side surface of the fourth lens are convex, the object side surface of the fifth lens is concave, and the object side surface of the sixth lens is convex.

3. The optical lens according to claim 1, characterized in that: The fourth lens and the fifth lens are cemented to form a cemented lens.

4. The optical lens according to claim 1, characterized in that: The optical power of the first lens to the sixth lens meets the following conditions: -0.74≤φ1 / φ≤-0.55; 0.19≤φ2 / φ≤0.44; 0.49≤φ3 / φ≤0.69; 0.58≤φ4 / φ≤0.91; -1.17≤φ5 / φ≤-0.69; 0.35≤φ6 / φ≤0.54; Wherein, φ is the optical power of the optical lens, and φ1, φ2, φ3, φ4, φ5, and φ6 represent the optical powers of the first lens to the sixth lens in order.

5. The optical lens according to claim 1, characterized in that: The refractive index and Abbe number of the first to sixth lenses satisfy the following conditions: 1.75≤n1≤1.87;38.5≤v1≤50.5; 1.58≤n2≤1.94;33.5≤v2≤41.5; 1.63≤n3≤1.84;44.5≤v3≤59.9; 1.55≤n4≤1.64;60.5≤v4≤72.5; 1.76≤n5≤1.97;17.3≤v5≤27.2; 1.73≤n6≤1.98;30.5≤v6≤51.5; Among them, n1, n2, n3, n4, n5, and n6 represent the refractive indices of the first lens to the sixth lens in sequence, respectively, and v1, v2, v3, v4, v5, and v6 represent the Abbe numbers of the first lens to the sixth lens in sequence.

6. The optical lens according to claim 1, characterized in that: The Abbe number Vd4 and the refractive index Nd4 of the fourth lens satisfy the Abbe number Vd5 and the refractive index Nd5 of the fifth lens: 2.5<Vd4 / Vd5<3.6; 0.8<Nd4 / Nd5<0.

9.

7. The optical lens according to claim 1, characterized in that: The effective focal length EFFL of the optical lens and the total optical length TTL of the optical lens satisfy: TTL / EFFL<5.

5.

8. The optical lens according to claim 1, characterized in that: An entrance pupil diameter ENPD of the optical lens and a total optical length TTL of the optical lens satisfy: ENPD / TTL>0.

1.

9. The optical lens according to claim 1, characterized in that: The central curvature radius R1 of the object side of the first lens and the effective focal length EFFL of the optical lens satisfy: 0.8<R1 / EFFL<1.

5.

10. The optical lens according to claim 1, characterized in that: The optical back focus BFL of the optical lens and the total optical length TTL of the optical lens satisfy: BFL / TTL≥0.11.

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