Optical lens

Abstract

The utility model discloses an optical lens comprising 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 embodiment of the utility model relates 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 its increasing level of intelligence, people are paying more and more attention to driving safety, leading to the emergence of various assisted driving functions. As a key component of ADAS (Advanced Driver Assistance Systems), automotive cameras can perceive the vehicle's surrounding conditions in real time, enabling functions such as forward collision warning, lane departure warning, and pedestrian detection. Their performance directly affects the safety factor of ADAS, thus, the performance requirements for automotive cameras are becoming increasingly 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. Utility Model Content

[0004] The utility model provides an optical lens, which adopts 6 lenses and realizes 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] The embodiment of the utility model provides an optical lens, comprising a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence along an optical axis from an object plane to an image plane; the surface of the lens close to the object plane is the object side surface, and the surface of the lens close to the image plane is the 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 along 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 image side surface of the second lens are both convex, the object side surface and image side surface of the third lens are both convex, the object side surface and image side surface of the fourth lens are both 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] in, is the focal length of the optical lens, The optical powers of the first lens to the sixth lens are represented in order.

[0012] Optionally, the refractive index and Abbe number of the first to sixth lenses satisfy the following conditions:

[0013] 1.75≤n1≤1.87;38.5≤v1≤50.5;

[0014] 1.58≤n2≤1.94;33.5≤v2≤41.5;

[0015] 1.63≤n3≤1.84;44.5≤v3≤59.9;

[0016] 1.55≤n4≤1.64;60.5≤v4≤72.5;

[0017] 1.76≤n5≤1.97;17.3≤v5≤27.2;

[0018] 1.73≤n6≤1.98;30.5≤v6≤51.5;

[0019] Here, n1, n2, n3, n4, n5, and n6 represent the refractive indices of the first to sixth lenses, respectively, and v1, v2, v3, v4, v5, and v6 represent the Abbe numbers of the first to sixth lenses, respectively.

[0020] Optionally, the effective focal length EFFL of the optical lens and the total optical length TTL of the optical lens satisfy the following relationship:

[0021] TTL / EFFL<5.5.

[0022] Optionally, an entrance pupil diameter ENPD of the optical lens and a total optical length TTL of the optical lens satisfy the following relationship: ENPD / TTL>0.1.

[0023] Optionally, the central curvature radius R1 of the objective side of the first lens and the effective focal length EFFL of the lens satisfy the following relationship: 0.8<R1 / EFFL<1.5.

[0024] 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:

[0025] 2.5<Vd4 / Vd5<3.6; 0.8<Nd4 / Nd5<0.9.

[0026] Optionally, the optical back focus BFL of the optical lens and the total optical length TTL of the optical lens satisfy the following relationship: BFL / TTL≥0.11.

[0027] Optionally, a stop is further included, and the stop is located between the second lens and the third lens.

[0028] The optical lens provided in an embodiment of the present application includes six lenses arranged in sequence along the optical axis from the object plane to the image plane. The optical powers of the six 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 at high and low temperatures is achieved, meeting the market demand for automotive camera lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic structural diagram of an optical lens provided in the first embodiment of the application;

[0030] Figure 2 A ray fan diagram of an optical lens provided in Example 1 of the application;

[0031] Figure 3 An axial aberration diagram of an optical lens provided in Example 1 of the application;

[0032] Figure 4 A structural diagram of an optical lens provided in the second embodiment of the application;

[0033] Figure 5 A ray fan diagram of an optical lens provided in the second embodiment of the application;

[0034] Figure 6 An axial aberration diagram of an optical lens provided in the second embodiment of the application;

[0035] Figure 7 A structural diagram of an optical lens provided in the third embodiment of the application;

[0036] Figure 8 A ray fan diagram of an optical lens provided in the third embodiment of the application;

[0037] Figure 9 This is an axial aberration diagram of an optical lens provided in application embodiment 3. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should 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 of its components.

[0039] Figure 1 A schematic diagram of the structure of an optical lens provided in the first embodiment of the application is provided. Figure 1 The optical lens provided by the embodiment of the present invention includes a lens along the optical axis ( Figure 1 (as indicated by the arrow in the middle) 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 center of the lens to the image plane IMA (not shown);

[0040] The first lens L1 is a glass aspherical lens with negative optical power; the second lens L2 is a glass spherical lens with positive optical power; the third lens L3 is a glass spherical lens with positive optical power; the fourth lens L4 is a glass spherical lens with positive optical power; the fifth lens L5 is a glass spherical lens with negative optical power; and the sixth lens L6 is a glass spherical lens with positive optical power.

[0041] 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 L6 can be arranged in sequence along the optical axis from the object plane to the image plane in a lens barrel ( Figure 1 (not shown). It should be noted that Figure 1 The structural schematic diagrams corresponding to the subsequent embodiments are merely schematic diagrams of the structures, and shapes such as aspherical surfaces are not represented according to actual conditions.

[0042] Among them, the optical power 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, which characterizes the ability of the optical lens to deflect light. The larger the absolute value of the optical power, the stronger the ability to bend light, and the smaller the absolute value of the optical power, the weaker the ability to bend light. When the optical power is a positive number, the refraction of light is convergent; when the optical power is a negative number, the refraction of light is divergent. The optical power can be used to characterize a certain refractive surface of a lens (that is, 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 (that is, a lens group).

[0043] The aperture OTS includes an aperture stop and a field stop. The aperture stop refers to the stop that limits the light beam the most, and the field stop refers to the stop that limits the field of view (size) the most.

[0044] The front end of the aperture STO uses a first lens L1 with negative optical power and a second lens L2 with positive optical power. The first lens L1 diverges the incident light, and the second lens L2 converges the light. By reasonably matching the optical powers 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 to meet the usage requirements under different conditions.

[0045] The aperture STO is positioned between the positive-power second lens L2 and the positive-power third lens L3. It adjusts the direction of the light beam emitted from the second lens L2 to the incident surface of the third lens L3, thereby limiting the light beam or field of view within the optical lens. Furthermore, the second lens L2 at the front of the aperture STO converges the light, preventing stray light such as reflections at the aperture STO position while also adjusting the lens's aberrations to a certain extent, ensuring balanced aberrations and stable high and low-temperature performance.

[0046] 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 to first expand the converged light and then converge 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.

[0047] Considering the strong light-bending capabilities of glass lenses, which effectively correct lens aberrations, this application employs a glass aspherical lens for the first lens L1, and a glass spherical lens for the second, third, fourth, fifth, and sixth lenses L6. This reduces the number of lenses and the size of the lens. It also ensures excellent resolution across a wide range of high and low temperatures, meeting the performance requirements of automotive lenses.

[0048] For example, it can still maintain good performance in the ambient temperature range of -40 to 95°C.

[0049] 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.

[0050] Considering that aspherical lenses have a good ability to control 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:

[0051]

[0052] Among them, z represents the axial sagittal height in the Z direction of the aspheric surface; 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 curvature radius; k represents the fitted cone coefficient; A, B, C, D, E, F, and G represent the 4th-order, 6th-order, 8th-order, 10th-order, 12th-order, 14th-order, and 16th-order coefficients of the aspheric polynomial, respectively.

[0053] 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 surface, and the surface of the lens close to the image plane is the image side surface.

[0054] The object-side surface of the first lens L1 is convex, and the image-side surface is concave. The object-side and image-side surfaces of the second lens L2 are both convex. The object-side and image-side surfaces of the third lens L3 are both convex. The object-side and image-side surfaces 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.

[0055] 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.

[0056] The concave lens has a diverging effect on the transmitted light, while the convex lens has a converging effect on the transmitted light. By properly setting the surface shapes of the first lens L1 to the sixth lens L6, clear imaging can be achieved at various focal lengths of the optical lens.

[0057] Based on the above embodiments, Figure 1 , the refractive powers of the first lens L1 to the sixth lens L6 satisfy the following conditions:

[0058]

[0059] in, is the optical power of the optical lens, The optical powers of the first lens L1 to the sixth lens L6 are represented in order.

[0060] 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.

[0061] Based on the above embodiments, Figure 1The fourth lens L4 and the fifth lens L5 are cemented together to form a cemented lens. This can effectively reduce the air gap between the fourth lens L4 and the fifth lens L5, shorten the overall length of the optical lens, and help eliminate chromatic aberration.

[0062] 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:

[0063] 1.75≤n1≤1.87;38.5≤v1≤50.5;1.58≤n2≤1.94;33.5≤v2≤41.5;

[0064] 1.63≤n3≤1.84;44.5≤v3≤59.9;1.55≤n4≤1.64;60.5≤v4≤72.5;

[0065] 1.76≤n5≤1.97;17.3≤v5≤27.2;1.73≤n6≤1.98;30.5≤v6≤51.5.

[0066] Here, n1, n2, n3, n4, n5, and n6 represent the refractive indices of the first lens L1 to the sixth lens L6, respectively, and v1, v2, v3, v4, v5, and v6 represent the Abbe numbers of the first lens L1 to the sixth lens L6, respectively.

[0067] The refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. It primarily describes a material's ability to refract light. Different materials have different refractive indices; the higher the refractive index, the slower the light propagates through the material. The Abbe number, also known as the dispersion coefficient, is an index used to indicate the dispersion capacity of a transparent medium. The greater the dispersion, the smaller the Abbe number; conversely, the less dispersion, the larger the Abbe number.

[0068] Generally speaking, refractive index and 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 present embodiment, by rationally designing the refractive index and Abbe number of the first lens L1 through the sixth lens L6, and selecting a variety of material combinations with different refractive indices and Abbe numbers, the imaging effect of the optical lens is improved while minimizing chromatic aberration.

[0069] This application uses 6 glass lenses, the first lens L1 is 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. Compared with plastic lenses, by selecting glass lenses with a higher refractive index, the lens's refractive power of light can be effectively increased. At the same time, the glass lenses have a wide range of matching options for the refractive index and Abbe number. 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 a near-cemented effect, thereby playing a role in achromatism.

[0070] 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 so as to satisfy:

[0071] 2.5<Vd4 / Vd5<3.6;0.8<Nd4 / Nd5<0.9. Such an arrangement is conducive to cementing the fourth lens L4 and the fifth lens L5 together, eliminating chromatic aberration after light passes through the two lenses.

[0072] 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, abbreviated as EFFL) of the optical lens satisfy the following relationship: 0.8<R1 / EFFL<1.5.

[0073] 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 degree of 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: the change 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 curvature radius 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.

[0074] 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 meet the following relationship: TTL / EFFL<5.5.

[0075] The total optical length (TTL) and effective focal length (EFFL) of an optical lens directly impact its imaging performance and applicable scenarios. The total optical length (TTL) of an optical lens refers to the distance from the object side of the first lens element L1 to the image plane. The effective focal length (EFFL) refers to the distance from the optical center (principal point) of the lens to the imaging plane (focal point). The longer the effective focal length (EFFL), the more distant objects can be magnified; the shorter the effective focal length (EFFL), the wider the shooting range. Regarding imaging performance, the relationship between the total optical length (TTL) and effective focal length (EFFL) of an optical lens directly impacts the lens's imaging performance. The longer the effective focal length (EFFL), the narrower the imaging range, but it can capture more distant objects; the shorter the effective focal length (EFFL), the wider the imaging range, but the shooting distance is shorter. Regarding applicable scenarios: long focal length lenses are suitable for capturing distant objects or scenes that require magnified details, such as telescopes and telephoto cameras; short focal length lenses are suitable for capturing expansive scenes or scenes that require a wide field of view, such as landscape photography and surveillance cameras. This application satisfies the following requirement by reasonably controlling the ratio of the total optical length TTL and the effective focal length EFFL of the optical lens: TTL / EFFL<5.5. In this way, while ensuring high-quality imaging, it meets the scene application requirements of the vehicle-mounted camera lens.

[0076] 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 meet the following conditions: ENPD / TTL>0.1.

[0077] 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. This application reasonably controls the ratio of the entrance pupil diameter ENPD of the optical lens to 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 lens miniaturization, and at the same time improving the brightness and resolution of the image, thereby meeting the market demand for vehicle-mounted camera lenses.

[0078] 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 meet the following conditions: BFL / TTL ≥ 0.11.

[0079] The back focus (BFL) of an optical lens refers to the distance from the rearmost lens surface to the image plane along the optical axis, specifically the distance from the image side of the sixth lens element L6 to the image plane IMA in this application. The back focus (BFL) directly impacts the final image quality of the optical lens and the space required for system installation. By properly setting the ratio of the back focus (BFL) to the total optical length (TTL) to at least 0.11, the installation requirements for vehicle-mounted camera lenses can be met, effectively satisfying the requirements for compact applications.

[0080] In addition to the above embodiment, the optical lens may further include a flat glass plate CG disposed in the optical path between the sixth lens element L6 and the image plane IMA. The flat glass plate CG may protect the photosensitive chip in the imaging sensor. The imaging chip is used to convert the light signals collected by the optical lens into electrical signals, thereby ensuring the imaging effect of the optical lens.

[0081] Reference Figure 1 As shown, the various lenses 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 that the mirror surface of each lens is stable and clear and the imaging quality is guaranteed, which is not shown in the embodiment of the present application.

[0082] In summary, the optical lens provided in the embodiment of the present invention adopts a 6-lens structure. By optimizing the shape, optical focal length and relative position of each lens, an optical lens with the characteristics of large aperture, high clarity, small size, and no large deviation in resolution at high and low temperatures is achieved, which meets the market demand for vehicle-mounted camera lenses.

[0083] Specific embodiments of the optical lens applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0084] Example 1

[0085] Continue to refer Figure 1 The optical lens provided in the first embodiment of the present invention includes a lens along the optical axis ( Figure 1 (as indicated by the arrow in the middle) from the object plane ( Figure 1Arranged in sequence from the sixth lens L6 to the image plane IMA (not shown) are 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. The first lens L1 is a glass aspherical lens with negative optical power; the second lens L2 is a glass spherical lens with positive optical power; the third lens L3 is a glass spherical lens with positive optical power; the fourth lens L4 is a glass spherical lens with positive optical power; the fifth lens L5 is a glass spherical lens with negative optical power; and the sixth lens L6 is a glass spherical lens with positive optical power. A flat glass element CG is positioned between the sixth lens L6 and the image plane IMA. The flat glass element CG protects the photosensitive chip in the imaging sensor, which converts the optical signals collected by the optical lens into electrical signals, thereby ensuring the imaging effect of the optical lens.

[0086] 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.

[0087] Table 1 Design values ​​of optical physical parameters of optical lens

[0088] Surface number S Surface type Curvature radius R thickness Materials (nd) Material (vd) S1 Aspheric 5.67 3.50 1.77 49.00 S2 Aspheric 1.87 1.85 S3 spherical surface 16.93 5.50 1.88 40.00 S4 spherical surface -16.93 -0.05 aperture spherical surface Infinity 1.22 S6 spherical surface 9.25 2.79 1.65 58.40 S7 spherical surface -9.25 0.11 S8 spherical surface 10.90 2.00 1.60 68.00 S9 spherical surface -4.26 1.64 1.78 25.72 S10 spherical surface 30.15 0.16 S11 spherical surface 9.14 1.78 1.88 40.13 S12 spherical surface 59.40 0.64 S13 flat Infinity 0.60 1.52 64.20 S14 flat Infinity 1.61 S15 Image plane Infinity

[0089] The surface number S in Table 1 is numbered according to the order of the lens surfaces; "STO" represents the aperture of the optical lens; IMA represents the image plane; the radius of curvature R represents the degree of curvature of the lens surface; a positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane; "Infinity" indicates 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 nd represents the light deflection ability of the material between the current and next surfaces; a blank space represents the current position as air with a refractive index of 1. The Abbe number vd represents the light dispersion characteristics of the material between the current and next surfaces; and the half-aperture represents half the lens aperture. The more severe the medium's dispersion, the smaller the Abbe number; conversely, the less severe the medium's dispersion, the larger the Abbe number.

[0090] In this embodiment, the aspherical lens of the optical lens can satisfy the following formula:

[0091]

[0092] Among them, z represents the axial sagittal height in the Z direction of the aspheric surface; 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 curvature radius; k represents the fitted cone coefficient; A, B, C, D, E, F, and G represent the 4th-order, 6th-order, 8th-order, 10th-order, 12th-order, 14th-order, and 16th-order coefficients of the aspheric polynomial, respectively.

[0093] For example, Table 2 describes in detail the aspheric coefficients of each lens in the first embodiment in a feasible implementation manner.

[0094] Table 2 Design values ​​of aspheric coefficients of each lens in the optical lens

[0095] 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

[0096] Among them, 1.38E-03 means that the coefficient A of the surface number S1 is 1.38*10-3, and so on.

[0097] Furthermore, a number of performance tests were conducted on the optical lens provided in Example 1, and the test results are as follows:

[0098] Figure 2 The light fan diagram of an optical lens provided in the first embodiment of the application is a diagram of a light fan. 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. The corresponding interval on the vertical axis of the curve is the maximum diffusion 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 aligned with the horizontal axis at all wavelengths in all fields of view, indicating that the vertical axis aberration of the optical lens at all wavelengths is well corrected. At the same time, there is no obvious dispersion of the wavelengths from 0.436 μm to 0.656 nm, indicating that the system chromatic aberration is also well corrected, thereby ensuring that the optical lens can achieve high-resolution imaging requirements.

[0099] 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 of 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.

[0100] Example 2

[0101] Figure 4 For the structural diagram of an optical lens provided in the second embodiment of the application, refer to Figure 4 The optical lens provided in the first embodiment of the present invention includes a lens along the optical axis ( Figure 4 (as indicated by the arrow in the middle) from the object plane ( Figure 4 Arranged in sequence from the sixth lens L6 to the image plane IMA (not shown) are 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. The first lens L1 is a glass aspherical lens with negative optical power; the second lens L2 is a glass spherical lens with positive optical power; the third lens L3 is a glass spherical lens with positive optical power; the fourth lens L4 is a glass spherical lens with positive optical power; the fifth lens L5 is a glass spherical lens with negative optical power; and the sixth lens L6 is a glass spherical lens with positive optical power. A flat glass element CG is positioned between the sixth lens L6 and the image plane IMA. The flat glass element CG protects the photosensitive chip in the imaging sensor, which converts the optical signals collected by the optical lens into electrical signals, thereby ensuring the imaging effect of the optical lens.

[0102] 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 Example 2 of the present utility model.

[0103] Table 3 Design values ​​of optical physical parameters of optical lens

[0104] Surface number S Surface type Curvature radius R thickness Materials (nd) Material (vd) S1 Aspheric 5.36 3.38 1.85 40.00 S2 Aspheric 1.94 1.70 S3 spherical surface 25.00 5.46 1.60 38.00 S4 spherical surface -25.00 0.05 aperture spherical surface Infinity 0.10 S6 spherical surface 8.60 3.56 1.82 46.00 S7 spherical surface -11.74 0.52 S8 spherical surface 8.63 2.46 1.57 70.99 S9 spherical surface -3.71 0.80 1.81 23.00 S10 spherical surface 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

[0105] The surface number S in Table 3 is numbered according to the order of the lens surfaces. The radius of curvature R represents the degree of curvature of the lens surface; a positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane. "Infinity" indicates that the surface is flat and has an infinite radius of curvature. The thickness represents the axial distance from the center of the current surface to the next surface. The refractive index nd represents the light-bending ability of the material between the current and next surfaces. A blank space represents the current position as air with a refractive index of 1. The Abbe number vd represents the light-dispersion properties of the material between the current and next surfaces. The half-aperture represents half the lens aperture. The greater the dispersion of the medium, the smaller the Abbe number; conversely, the less dispersion there is, the larger the Abbe number.

[0106] In this embodiment, the aspherical lens of the optical lens can satisfy the following formula:

[0107]

[0108] Among them, z represents the axial sagittal height in the Z direction of the aspheric surface; 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 curvature radius; k represents the fitted cone coefficient; A, B, C, D, E, F, and G represent the 4th-order, 6th-order, 8th-order, 10th-order, 12th-order, 14th-order, and 16th-order coefficients of the aspheric polynomial, respectively.

[0109] For example, Table 4 describes in detail the aspheric coefficients of each lens in Example 2 of the present application in a feasible implementation manner.

[0110] Table 4 Design values ​​of aspheric coefficients of each lens in the optical lens

[0111] 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

[0112] Among them, 9.62E-04 means that the coefficient A of the surface number S1 is 9.62*10-4, and so on.

[0113] Furthermore, the performance parameters of the optical lens provided in Example 2 were tested, and the test results are as follows:

[0114] Figure 5 For the light fan diagram of an optical lens provided in the second embodiment of the application, refer to Figure 5 In the ray fan diagram, the horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The 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 ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also show 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 axis at all wavelengths in all fields of view, indicating that the vertical axis aberration of the optical lens at all wavelengths is well corrected. At the same time, there is no obvious dispersion of the wavelengths from 0.436 μm to 0.656 nm, indicating that the system chromatic aberration is also well corrected, thereby ensuring that the optical lens can achieve high-resolution imaging requirements.

[0115] 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 of 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.

[0116] Example 3

[0117] Figure 7 For the structural diagram of an optical lens provided in the second embodiment of the application, refer to Figure 7 The optical lens provided in the first embodiment of the present invention includes a lens along the optical axis ( Figure 7 (as indicated by the arrow in the middle) from the object plane ( Figure 7 Arranged in sequence from the sixth lens L6 to the image plane IMA (not shown) are 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. The first lens L1 is a glass aspherical lens with negative optical power; the second lens L2 is a glass spherical lens with positive optical power; the third lens L3 is a glass spherical lens with positive optical power; the fourth lens L4 is a glass spherical lens with positive optical power; the fifth lens L5 is a glass spherical lens with negative optical power; and the sixth lens L6 is a glass spherical lens with positive optical power. A flat glass element CG is positioned between the sixth lens L6 and the image plane IMA. The flat glass element CG protects the photosensitive chip in the imaging sensor, which converts the optical signals collected by the optical lens into electrical signals, thereby ensuring the imaging effect of the optical lens.

[0118] 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 Example 3 of the present utility model.

[0119] Table 5 Design values ​​of optical physical parameters of optical lens

[0120]

[0121]

[0122] The surface number S in Table 5 is numbered according to the order of the lens surfaces. The radius of curvature R represents the degree of curvature of the lens surface; a positive value indicates that the surface is curved toward the image plane, and a negative value indicates that the surface is curved toward the object plane. "Infinity" indicates that the surface is flat and has an infinite radius of curvature. The thickness represents the axial distance from the center of the current surface to the next surface. The refractive index nd represents the light-bending ability of the material between the current and next surfaces. A blank space represents the current position as air with a refractive index of 1. The Abbe number vd represents the light-dispersion properties of the material between the current and next surfaces. The half-aperture represents half the lens aperture. The greater the dispersion of the medium, the smaller the Abbe number; conversely, the less dispersion there is, the larger the Abbe number.

[0123] In this embodiment, the aspherical lens of the optical lens can satisfy the following formula:

[0124]

[0125] Among them, z represents the axial sagittal height in the Z direction of the aspheric surface; 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 curvature radius; k represents the fitted cone coefficient; A, B, C, D, E, F, and G represent the 4th-order, 6th-order, 8th-order, 10th-order, 12th-order, 14th-order, and 16th-order coefficients of the aspheric polynomial, respectively.

[0126] For example, Table 6 describes in detail the aspheric coefficients of each lens in Example 3 of the present application in a feasible implementation manner.

[0127] Table 6 Design values ​​of aspheric coefficients of each lens in the optical lens

[0128] Surface number k A B C D E F S1 -4.43E+00 3.64E-03 -3.49E-04 9.77E-06 -9.71E-08 1.68E-12 0.00E+00 S2 -9.10E-01 -2.46E-03 -1.19E-03 9.95E-05 -2.51E-06 -1.40E-08 0.00E+00

[0129] Among them, 3.64E-03 means that the coefficient A of the surface number S1 is 3.64*10 -3 , and so on.

[0130] Furthermore, the performance parameters of the optical lens provided in Example 3 were tested, and the test results are as follows:

[0131] Figure 7 For the light fan diagram of an optical lens provided in the third embodiment of the application, refer to Figure 7 In the ray fan diagram, the horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The 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 ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also show the size of the vertical axis chromatic aberration. Figure 7It can be seen that the optical lens provided in Example 2 of the present application is well aligned with the horizontal axis at all wavelengths in all fields of view, indicating that the vertical axis aberration of the optical lens at all wavelengths is well corrected. At the same time, there is no obvious dispersion of the wavelengths from 0.436 μm to 0.656 nm, indicating that the system chromatic aberration is also well corrected, thereby ensuring that the optical lens can achieve high-resolution imaging requirements.

[0132] 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 of 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.

[0133] In summary, in Example 1, Example 2, and Example 3 of the present application, the optical and physical parameters of the first to sixth lenses are shown in Table 7.

[0134] Table 7 Design values ​​of optical physical parameters of optical lens

[0135]

[0136] Note that the above are only preferred embodiments of the present invention and the technical principles employed. 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 are possible for 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 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: comprising a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence along the optical axis from the object plane to the image plane; 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, wherein: Along the direction of the optical axis 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, wherein: The fourth lens and the fifth lens are cemented together to form a cemented lens.

4. The optical lens according to claim 1, wherein: 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, respectively, in order.

5. The optical lens according to claim 1, wherein: 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; Here, n1, n2, n3, n4, n5, and n6 represent the refractive indices of the first to sixth lenses, respectively, and v1, v2, v3, v4, v5, and v6 represent the Abbe numbers of the first to sixth lenses, respectively.

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

9.

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

5.

8. The optical lens according to claim 1, wherein: The entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens satisfy the following relationship: ENPD / TTL>0.

1.

9. The optical lens according to claim 1, wherein: The central curvature radius R1 of the objective side of the first lens and the effective focal length EFFL of the optical lens satisfy the following relationship: 0.8<R1 / EFFL<1.

5.

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

Images