A fixed focus lens and a vehicle-mounted camera

Abstract

The application discloses a fixed-focus lens, which comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence along an optical axis from an object plane to an image plane; the first lens has negative optical power, the second lens has positive optical power, the third lens has positive optical power, the fourth lens has positive optical power, and the fifth lens has negative optical power; wherein the optical aperture D of the first lens and the total length TTL of the optical system of the fixed-focus lens satisfy 0.1<=D / TTL<=0.5. The technical scheme of the application can realize a large field angle range and meet the requirements of miniaturization and small aperture.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and more particularly to a fixed-focus lens and an in-vehicle camera. Background Technology

[0002] With the continuous advancement of science and technology and the ongoing development of society, optical imaging lenses have also experienced rapid development in recent years, and are widely used in various fields such as smartphones, tablets, video conferencing, dashcams, and security monitoring. Therefore, the requirements for optical imaging lenses are becoming increasingly stringent. Among these, optical lenses used in dashcams play a crucial role in driving safety.

[0003] However, current optical lenses used for dashcams still have many shortcomings, and how to further improve the performance of optical lenses has become an urgent technical problem to be solved. Summary of the Invention

[0004] This invention provides a fixed-focus lens and an automotive camera to achieve a wide field of view while meeting the requirements of miniaturization and small aperture.

[0005] According to one aspect of the present invention, a fixed-focus lens is provided, comprising: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object plane to the image plane;

[0006] The first lens has negative optical power, the second lens has positive optical power, the third lens has positive optical power, the fourth lens has positive optical power, and the fifth lens has negative optical power.

[0007] Wherein, the optical aperture D of the first lens and the total optical system length TTL of the fixed-focus lens satisfy: 0.1≤D / TTL≤0.5.

[0008] Optionally, the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all glass spherical lenses.

[0009] Optionally, the first lens, the second lens, the fourth lens, and the fifth lens are all glass spherical lenses; the third lens is a glass aspherical lens.

[0010] Optionally, the fourth lens and the fifth lens are cemented lenses.

[0011] Optionally, the optical power of the first lens is φ1, the optical power of the second lens is φ2, the optical power of the third lens is φ3, the optical power of the fourth lens is φ4, the optical power of the fifth lens is φ5, and the optical power of the fixed-focus lens is φ.

[0012] Among them, -1.5≤φ1 / φ≤0, 0.1≤φ2 / φ≤0.8, 0.1≤φ3 / φ≤0.7, 0.5≤φ4 / φ≤1.2, and -1.2≤φ5 / φ≤0.

[0013] Optionally, the refractive index of the fourth lens is n4, and the refractive index of the fifth lens is n5; wherein, 0.85≤n4 / n5≤1.15.

[0014] Optionally, the fixed-focus lens further includes: an aperture stop;

[0015] The aperture stop is located in the optical path between the second lens and the third lens.

[0016] Optionally, the Abbe constant Vd4 of the fourth lens has the following range: 31 < Vd4 < 50.

[0017] Optionally, the diagonal image height of the effective imaging area of ​​the imaging surface of the fixed-focus lens is ImgH; wherein, 2.2≤TTL / ImgH≤3.2.

[0018] According to another aspect of the present invention, an in-vehicle camera is provided, comprising: the aforementioned focal lens.

[0019] The technical solution of this invention, by sequentially arranging a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with positive optical power, and a fifth lens with negative optical power along the optical axis from the object plane to the image plane, uses only five lenses. The optical power of each lens is reasonably arranged, which can meet the requirements of a large field of view, high imaging quality, and miniaturization. At the same time, by setting the optical aperture D of the first lens and the total optical system length TTL of the fixed-focus lens to satisfy 0.1≤D / TTL≤0.5, the requirement of a small aperture can be met while achieving miniaturization.

[0020] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a fixed-focus lens provided in an embodiment of the present invention;

[0023] Figure 2 To and Figure 1 A diagram illustrating the field curvature and distortion of a corresponding prime lens;

[0024] Figure 3 To and Figure 1 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens;

[0025] Figure 4 To and Figure 1 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens;

[0026] Figure 5 This is a schematic diagram of another fixed-focus lens provided in an embodiment of the present invention;

[0027] Figure 6 To and Figure 5 A diagram illustrating the field curvature and distortion of a corresponding prime lens;

[0028] Figure 7 To and Figure 5 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens;

[0029] Figure 8 To and Figure 5 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens;

[0030] Figure 9 This is a schematic diagram of another fixed-focus lens provided in an embodiment of the present invention;

[0031] Figure 10 To and Figure 9 A diagram illustrating the field curvature and distortion of a corresponding prime lens;

[0032] Figure 11 To and Figure 9 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens;

[0033] Figure 12 To and Figure 9 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens;

[0034] Figure 13 This is a schematic diagram of another fixed-focus lens provided in an embodiment of the present invention;

[0035] Figure 14 To and Figure 13 A diagram illustrating the field curvature and distortion of a corresponding prime lens;

[0036] Figure 15 To and Figure 13 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens;

[0037] Figure 16 To and Figure 13 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens;

[0038] Figure 17 This is a schematic diagram of the structure of another fixed-focus lens provided in an embodiment of the present invention;

[0039] Figure 18 To and Figure 17 A diagram illustrating the field curvature and distortion of a corresponding prime lens;

[0040] Figure 19 To and Figure 17 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens;

[0041] Figure 20 To and Figure 17 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens;

[0042] Figure 21 This is a schematic diagram of the structure of another fixed-focus lens provided in an embodiment of the present invention;

[0043] Figure 22 To and Figure 21 A diagram illustrating the field curvature and distortion of a corresponding prime lens;

[0044] Figure 23 To and Figure 21 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens;

[0045] Figure 24 To and Figure 21 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens. Detailed Implementation

[0046] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0047] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a system, product, or device comprising a series of units is not necessarily limited to those steps or units explicitly listed, but may include other units not explicitly listed or inherent to such products or devices.

[0048] This invention provides a fixed-focus lens that can be applied to vehicle cameras, such as dashcams, to meet the requirements of a wide field of view, miniaturization, small aperture, and high imaging quality. Figure 1 This is a schematic diagram of the structure of a fixed-focus lens provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the fixed-focus lens includes: a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, and a fifth lens 50 arranged sequentially along the optical axis from the object plane to the image plane; the first lens 10 has negative optical power, the second lens 20 has positive optical power, the third lens 30 has positive optical power, the fourth lens 40 has positive optical power, and the fifth lens 50 has negative optical power; wherein, the optical aperture D of the first lens 10 and the total optical system length TTL of the fixed-focus lens satisfy: 0.1≤D / TTL≤0.5.

[0049] Specifically, optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam; it characterizes the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger the bending ability of light; the smaller the absolute value, the weaker the bending ability. When the optical power is positive, the refraction of light is converging; when the optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group). In the medium-telephoto lens provided in this embodiment, all lenses can be fixed in a single lens barrel (…). Figure 1(Not shown in the image). In this embodiment of the invention, by using only five lenses and rationally allocating the optical power of each lens, and setting the first lens 10 closest to the object side to have a negative optical power, the incident angle of the light in the optical system can be controlled, thus correcting field curvature. This allows the fixed-focus lens to have miniaturization characteristics while meeting the requirements of a large field of view and high imaging quality. At the same time, by setting the optical aperture D of the first lens 10 and the total optical system length TTL of the fixed-focus lens to satisfy 0.1≤D / TTL≤0.5, the fixed-focus lens can have a small aperture and a compact optical structure, meeting the miniaturization requirements. Therefore, when this fixed-focus lens is applied to an automotive camera, the automotive camera can have a small size, high imaging quality, and a large field of view.

[0050] Optionally, the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, and the fifth lens 50 are all glass spherical lenses.

[0051] In this embodiment, by using glass spherical lenses for the first lens 10, second lens 20, third lens 30, fourth lens 40, and fifth lens 50 of the fixed-focus lens, it is possible to eliminate the need for mold injection molding compared to plastic lenses, thus avoiding the development costs of molds and contributing to the low cost of the fixed-focus lens. Furthermore, since glass lenses have excellent temperature characteristics, when the first lens 10, second lens 20, third lens 30, fourth lens 40, and fifth lens 50 of the fixed-focus lens in this embodiment are all made of glass spherical lenses, the fixed-focus lens can maintain stable high and low temperature performance, for example, it can maintain high imaging quality within a temperature range of -40℃ to 85℃.

[0052] In other alternative embodiments, the first lens 10, the second lens 20, the fourth lens 40, and the fifth lens 50 are all glass spherical lenses; while the third lens 30 is a glass aspherical lens.

[0053] Spherical lenses have a constant curvature from their center to their edge, while aspherical lenses have a continuously changing curvature from their center to their edge. Aspherical lenses allow light rays to converge to a single point, enabling one aspherical lens to replace multiple spherical lenses and correct spherical aberration introduced by spherical lenses in collimation and focusing systems. Thus, by using a glass aspherical lens for the third lens 30, aberrations can be corrected, ensuring the optical performance of the fixed-focus lens and meeting the requirements for high image quality. Furthermore, since the first lens 10, second lens 20, third lens 30, fourth lens 40, and fifth lens 50 are all made of glass, the fixed-focus lens also maintains stable high and low temperature performance, for example, exhibiting high image quality within a temperature range of -40℃ to 85℃.

[0054] In an exemplary embodiment, the aspherical surface of the third lens 30 satisfies:

[0055]

[0056] Where Z represents the axial sagitta in the Z-direction of the aspherical surface; y represents the distance from a point on the aspherical surface to the optical axis; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; K represents the fitted conic coefficients; and a1, a2, a3, a4, a5, and a6 represent the 2nd, 4th, 6th, 8th, 10th, and 12th order coefficients of the aspherical polynomial, respectively.

[0057] Optionally, the fourth lens 40 and the fifth lens 50 are cemented lenses.

[0058] Cemented lenses can be used to minimize or eliminate chromatic aberration. Using cemented lenses in optical systems improves image quality and reduces light energy reflection loss, thereby enhancing the clarity of the image. Furthermore, the use of cemented lenses simplifies the assembly process in optical system manufacturing, improving equipment efficiency. In this embodiment, the image-side surface of the fourth lens 40 is cemented to the object-side surface of the fifth lens 50, i.e., the fourth lens 40 and the fifth lens 50 are cemented together. By assembling the fourth lens 40 and the fifth lens 50 into a cemented lens, the influence of chromatic aberration can be eliminated, reducing tolerance sensitivity; simultaneously, the cemented lens can also balance the overall chromatic aberration of the optical system. Cementing the lenses eliminates the air gap between the two lenses, making the overall optical system compact and meeting the requirements for system miniaturization. Moreover, cementing the lenses reduces tolerance sensitivity issues such as tilting / eccentricity that occur during lens assembly. Exemplarily, the fourth lens 40 and the fifth lens 50 can be supported by a gasket or cemented together with adhesive; this embodiment does not specifically limit the cementing method for the fourth lens 40 and the fifth lens 50.

[0059] Optionally, when the optical power of the first lens 10 is φ1, the optical power of the second lens 20 is φ2, the optical power of the third lens 30 is φ3, the optical power of the fourth lens 40 is φ4, the optical power of the fifth lens 50 is φ5, and the optical power of the fixed-focus lens is φ, then -1.5≤φ1 / φ≤0, 0.1≤φ2 / φ≤0.8, 0.1≤φ3 / φ≤0.7, 0.5≤φ4 / φ≤1.2, and -1.2≤φ5 / φ≤0.

[0060] Thus, by reasonably setting the optical power of the first lens 10, the second lens 20, the third lens 30, the fourth lens 40 and the fifth lens 50, the fixed-focus lens of the present invention has the characteristics of a large field of view, miniaturization and small aperture, while maintaining stable optical performance in a temperature range of -40℃ to 85℃, and has high relative illumination, thereby achieving high resolution and meeting the requirements of high imaging quality.

[0061] Optionally, when the refractive index of the fourth lens 40 is n4 and the refractive index of the fifth lens 50 is n5, 0.85≤n4 / n5≤1.15.

[0062] 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 a material's ability to refract light, and different materials have different refractive indices. By combining and setting the refractive indices of the fourth and fifth lenses, it is possible to achieve a miniaturized design of a fixed-focus lens while simultaneously achieving higher pixel resolution and reducing lens assembly tolerances.

[0063] Optionally, the Abbe constant Vd4 of the fourth lens 40 can be in the range of 31 < Vd4 < 50.

[0064] The Abbe number is an index used to represent the dispersion capability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion, the larger the Abbe number. By properly setting the Abbe number of the fourth lens 40, dispersion can be improved, image sharpness can be enhanced, and the requirements for high-resolution imaging can be met.

[0065] In an optional embodiment, when the refractive index of the first lens 10 is n1, the refractive index of the second lens 20 is n2, the refractive index of the third lens 30 is n3, the refractive index of the fourth lens 40 is n4, and the refractive index of the fifth lens 50 is n5, the refractive indices of each lens satisfy the following: 1.56 < n1 < 1.75, 1.92 < n2 < 2.05, 1.57 < n3 < 2.05, 1.72 < n4 < 1.96, and 1.84 < n5 < 2.

[0066] Optionally, the diagonal image height of the effective imaging area of ​​the fixed-focus lens is ImgH; where 2.2≤TTL / ImgH≤3.2. This ensures that while achieving miniaturization, imaging can be performed over a wide field of view, meeting the requirements for high-quality imaging.

[0067] Optionally, based on the above embodiments, the fixed-focus lens may further include an aperture stop 60, which is located in the optical path between the second lens 20 and the third lens 30.

[0068] The addition of an aperture stop 60 can adjust the direction of beam propagation, which is beneficial to improving image quality. Furthermore, by setting the aperture stop 60 in a suitable position, it can help improve relative illumination and reduce the angle of the principal rays.

[0069] This invention employs only five lenses, arranged sequentially along the optical axis from the object plane to the image plane: a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with positive optical power, and a fifth lens with negative optical power. The reasonable arrangement of the optical powers of each lens achieves the requirements of a wide field of view, high image quality, and miniaturization. Furthermore, by setting the optical aperture D of the first lens and the total optical system length TTL of the fixed-focus lens to satisfy 0.1 ≤ D / TTL ≤ 0.5, miniaturization is achieved while meeting the requirement of a small aperture. In addition, the fixed-focus lens of this invention exhibits stable high and low temperature performance, maintaining high image quality within a temperature range of -40℃ to 85℃.

[0070] As a feasible embodiment, the design parameters of various lenses in a fixed-focus lens are described below as an example.

[0071] In one exemplary embodiment, Table 1 is related to Figure 1 The specific parameters of each lens in the corresponding fixed-focus lens.

[0072] Table 1. Parameter design of each lens in a fixed-focus lens.

[0073] Example 1 lower limit upper limit φ1 / φ -0.78 -1.5 0 φ2 / φ 0.52 0.1 0.8 φ3 / φ 0.18 0.1 0.7 φ4 / φ 0.99 0.5 1.2 φ5 / φ -0.55 -1.2 0 TTL / ImgH 2.35 2.2 3.2 D / TTL 0.43 0.1 0.5

[0074] In this embodiment, by reasonably setting the optical power of each lens and the fixed-focus lens, the ratio of the optical aperture D of the first lens 10 to the total optical system length TTL of the fixed-focus lens, D / TTL, is only 0.43, and the ratio of the total optical system length TTL of the fixed-focus lens to the diagonal image height ImgH of the effective imaging area of ​​the fixed-focus lens, TTL / ImgH, is 2.35. Thus, the fixed-focus lens can have high imaging quality over a large field of view while meeting the requirements of miniaturization and small aperture.

[0075] Table 2 shows the design parameters of the surface type, radius of curvature, thickness, and material of each lens in a fixed-focus lens corresponding to Table 1.

[0076] Table 2. One design parameter for each lens in a fixed-focus lens.

[0077] Face number Face type radius of curvature / mm Thickness / mm Refractive index Abbe number OBJ surface Infinity Infinity S1 spherical 15.96 1.10 1.72 38.3 S2 spherical 2.23 0.80 S3 spherical 7.61 3.30 2.0 25.4 S4 spherical -15.94 -0.001 S5 Aperture Infinity 0.23 S6 spherical -3.95 2.51 2.0 25.4 S7 spherical -4.17 0.10 S8 spherical 8.34 1.67 1.75 49.9 S9 spherical -2.72 0.57 1.95 17.7 S10 spherical -6.61 0.6 S11 spherical Infinity 0.7 1.52 64.2 S12 spherical Infinity 3.47

[0078] refer to Figure 1The optical system provided in this embodiment includes a first lens 10 with negative optical power, a second lens 20 with positive optical power, a third lens 30 with positive optical power, a fourth lens 40 with positive optical power, and a fifth lens 50 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. Each lens is a glass spherical lens. Furthermore, an aperture stop 60 is provided in the optical path between the second lens 20 and the third lens 30, and a flat glass plate 70 can be provided between the image plane and the fifth lens 50. This flat glass plate 70 serves to filter light and provide protection. Table 2 shows the optical physical parameters of each lens in the optical system provided in this embodiment, including surface type, curvature diameter, thickness, and material. The surface number is assigned according to the order of the surfaces of each lens. For example, "OBJ" represents the object surface, "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, "S4" represents the image-side surface of the second lens 20, and so on. "S11" represents the object-side surface of the flat glass 70, and "S12" represents the image-side surface of the flat glass 70. The radius of curvature represents the degree of curvature of the lens surface. A positive value means that the surface bends towards the image surface, and a negative value means that the surface bends towards the object surface. The thickness represents the central axial distance from the current surface to the next surface. The unit of thickness is millimeters (mm). The refractive index and Abbe number indicate the material properties used in different lenses.

[0079] Figure 2 To and Figure 1 A diagram illustrating the field curvature and distortion of a corresponding prime lens; Figure 3 To and Figure 1 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens; Figure 4 To and Figure 1 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens; by Figures 2-4 It can be seen that, under the premise of small size and small aperture, this embodiment can have stable high and low temperature performance and high imaging quality in the temperature range of -40℃ to 85℃.

[0080] In another exemplary embodiment, Figure 5 This is a schematic diagram of another fixed-focus lens provided in an embodiment of the present invention. Table 3 shows the structure of the lens. Figure 5 The specific parameters of each lens in the corresponding fixed-focus lens.

[0081] Table 3. Another parameter design for each lens in a fixed-focus lens.

[0082] Example 2 lower limit upper limit φ1 / φ -0.64 -1.5 0 φ2 / φ 0.33 0.1 0.8 φ3 / φ 0.19 0.1 0.7 φ4 / φ 1.07 0.5 1.2 φ5 / φ -0.54 -1.2 0 TTL / ImgH 2.35 2.2 3.2 D / TTL 0.44 0.1 0.5

[0083] In this embodiment, by reasonably setting the optical power of each lens and the fixed-focus lens, the ratio of the optical aperture D of the first lens 10 to the total optical system length TTL of the fixed-focus lens, D / TTL, is only 0.44. Furthermore, the ratio of the total optical system length TTL of the fixed-focus lens to the diagonal image height ImgH of the effective imaging area of ​​the fixed-focus lens, TTL / ImgH, is 2.35. This allows the fixed-focus lens to achieve high imaging quality over a wide field of view while meeting the requirements of miniaturization and small aperture.

[0084] Table 4 shows the design parameters of the surface type, radius of curvature, thickness, and material of each lens in a fixed-focus lens corresponding to Table 3.

[0085] Table 4. Another design parameter for each lens in a fixed-focus lens.

[0086] Face number Face type radius of curvature / mm Thickness / mm Refractive index Abbe number OBJ surface Infinity Infinity S1 spherical 7.74 0.79 1.72 38.3 S2 spherical 2.18 1.73 S3 spherical 6.69 2.05 1.96 17.5 S4 spherical 28 0.14 S5 Aperture Infinity 0.22 S6 spherical -4.32 2.36 2.0 25.4 S7 spherical -4.27 0.09 S8 spherical 7.96 1.75 1.76 49.9 S9 spherical -2.45 1.1 1.95 17.9 S10 spherical -4.78 0.6 S11 spherical Infinity 0.7 1.52 64.2 S12 spherical Infinity 3.5

[0087] refer to Figure 5 The optical system provided in this embodiment includes a first lens 10 with negative optical power, a second lens 20 with positive optical power, a third lens 30 with positive optical power, a fourth lens 40 with positive optical power, and a fifth lens 50 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. Each lens is a glass spherical lens. Furthermore, an aperture stop 60 is provided in the optical path between the second lens 20 and the third lens 30, and a flat glass plate 70 can be provided between the image plane and the fifth lens 50. This flat glass plate 70 serves to filter light and provide protection. Table 4 shows the optical physical parameters of each lens in the optical system provided in this embodiment, including surface type, curvature diameter, thickness, and material. The surface number is assigned according to the order of the surfaces of each lens. For example, "OBJ" represents the object surface, "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, "S4" represents the image-side surface of the second lens 20, and so on. "S11" represents the object-side surface of the flat glass 70, and "S12" represents the image-side surface of the flat glass 70. The radius of curvature represents the degree of curvature of the lens surface. A positive value means that the surface bends towards the image surface, and a negative value means that the surface bends towards the object surface. The thickness represents the central axial distance from the current surface to the next surface. The unit of thickness is millimeters (mm). The refractive index and Abbe number indicate the material properties used in different lenses.

[0088] Figure 6 To and Figure 5 A diagram illustrating the field curvature and distortion of a corresponding prime lens; Figure 7 To and Figure 5 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens; Figure 8 To and Figure 5 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens; by Figures 6-8 It can be seen that, under the premise of small size and small aperture, this embodiment can have stable high and low temperature performance and high imaging quality in the temperature range of -40℃ to 85℃.

[0089] As an exemplary embodiment, Figure 9 This is a schematic diagram of another fixed-focus lens provided in an embodiment of the present invention. Table 5 shows the structure of the lens. Figure 9 The specific parameters of each lens in the corresponding fixed-focus lens.

[0090] Table 5. Another parameter design for each lens in a fixed-focus lens.

[0091] Example 3 lower limit upper limit φ1 / φ -0.74 -1.5 0 φ2 / φ 0.45 0.1 0.8 φ3 / φ 0.21 0.1 0.7 φ4 / φ 0.96 0.5 1.2 φ5 / φ -0.52 -1.2 0 TTL / ImgH 2.28 2.2 3.2 D / TTL 0.46 0.1 0.5

[0092] In this embodiment, by reasonably setting the optical power of each lens and the fixed-focus lens, the ratio of the optical aperture D of the first lens 10 to the total optical system length TTL of the fixed-focus lens, D / TTL, is only 0.46, and the ratio of the total optical system length TTL of the fixed-focus lens to the diagonal image height ImgH of the effective imaging area of ​​the fixed-focus lens, TTL / ImgH, is 2.28. Thus, the fixed-focus lens can have high imaging quality over a large field of view while meeting the requirements of miniaturization and small aperture.

[0093] Table 6 shows the design parameters of the surface type, radius of curvature, thickness, and material of each lens in a fixed-focus lens corresponding to Table 5.

[0094] Table 6. Another design parameter for each lens in a fixed-focus lens.

[0095] Face number Face type radius / mm Thickness / mm Refractive index Abbe number OBJ surface Infinity Infinity S1 spherical 9.69 0.83 1.72 2.84 S2 spherical 2.09 0.87 S3 spherical 9.14 2.86 1.96 17.5 S4 spherical -15.99 0.008 S5 Aperture Infinity 0.22 S6 spherical -4.11 2.80 1.90 31.3 S7 spherical -4.08 0.10 S8 spherical 8.95 1.79 1.76 49.9 S9 spherical -2.75 0.7 1.95 17.9 S10 spherical -6.52 0.6 S11 spherical Infinity 0.7 1.52 64.2 S12 spherical Infinity 3.59

[0096] refer to Figure 9The optical system provided in this embodiment includes a first lens 10 with negative optical power, a second lens 20 with positive optical power, a third lens 30 with positive optical power, a fourth lens 40 with positive optical power, and a fifth lens 50 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. Each lens is a glass spherical lens. Furthermore, an aperture stop 60 is provided in the optical path between the second lens 20 and the third lens 30, and a flat glass plate 70 can be provided between the image plane and the fifth lens 50. This flat glass plate 70 serves to filter light and provide protection. Table 4 shows the optical physical parameters of each lens in the optical system provided in this embodiment, including surface type, curvature diameter, thickness, and material. The surface number is assigned according to the order of the surfaces of each lens. For example, "OBJ" represents the object surface, "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, "S4" represents the image-side surface of the second lens 20, and so on. "S11" represents the object-side surface of the flat glass 70, and "S12" represents the image-side surface of the flat glass 70. The radius of curvature represents the degree of curvature of the lens surface. A positive value means that the surface bends towards the image surface, and a negative value means that the surface bends towards the object surface. The thickness represents the central axial distance from the current surface to the next surface. The unit of thickness is millimeters (mm). The refractive index and Abbe number indicate the material properties used in different lenses.

[0097] Figure 10 To and Figure 9 A diagram illustrating the field curvature and distortion of a corresponding prime lens; Figure 11 To and Figure 9 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens; Figure 12 To and Figure 9 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens; by Figures 10-12 It can be seen that, under the premise of small size and small aperture, this embodiment can have stable high and low temperature performance and high imaging quality in the temperature range of -40℃ to 85℃.

[0098] As an exemplary embodiment, Figure 13 This is a schematic diagram of another fixed-focus lens provided in an embodiment of the present invention. Table 7 shows the structure of the fixed-focus lens. Figure 13 The specific parameters of each lens in the corresponding fixed-focus lens.

[0099] Table 7. Another parameter design for each lens in a fixed-focus lens.

[0100] Example 4 lower limit upper limit φ1 / φ -0.69 -1.5 0 φ2 / φ 0.14 0.1 0.8 φ3 / φ 0.67 0.1 0.7 φ4 / φ 0.91 0.5 1.2 φ5 / φ -0.79 -1.2 0 TTL / ImgH 3.14 2.2 3.2 D / TTL 0.39 0.1 0.5

[0101] In this embodiment, by reasonably setting the optical power of each lens and the fixed-focus lens, the ratio of the optical aperture D of the first lens 10 to the total optical system length TTL of the fixed-focus lens, D / TTL, is only 0.39, and the ratio of the total optical system length TTL of the fixed-focus lens to the diagonal image height ImgH of the effective imaging area of ​​the fixed-focus lens, TTL / ImgH, is 3.14. Thus, the fixed-focus lens can have high imaging quality over a large field of view while meeting the requirements of miniaturization and small aperture.

[0102] Table 8 shows the design parameters of the surface type, radius of curvature, thickness, and material of each lens in a fixed-focus lens corresponding to Table 7.

[0103] Table 8. Another design parameter for each lens in a fixed-focus lens.

[0104] Face number Face type radius / mm Thickness / mm Refractive index Abbe number OBJ surface Infinity 2000 S1 spherical 8.70 1.10 1.61 58.9 S2 spherical 2.10 1.04 S3 spherical 23.51 1.97 2.00 25.5 S4 spherical Infinity 0.10 S5 Aperture Infinity 1.28 S6 aspherical -14.03 2.16 1.62 66 S7 aspherical -2.69 0.06 S8 spherical 15.23 2.40 1.9 37.1 S9 spherical -3.94 0.82 1.92 20.9 S10 spherical Infinity 0.30 S11 spherical Infinity 0.60 1.52 64.2 S12 spherical Infinity 3.65

[0105] refer to Figure 13 The optical system provided in this embodiment includes a first lens 10 with negative optical power, a second lens 20 with positive optical power, a third lens 30 with positive optical power, a fourth lens 40 with positive optical power, and a fifth lens 50 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. The first lens 10, second lens 20, fourth lens 40, and fifth lens 50 are all spherical glass lenses, and the third lens 30 is a glass aspherical lens. Furthermore, an aperture stop 60 is provided in the optical path between the second lens 20 and the third lens 30, and a flat glass plate 70 can be provided between the image plane and the fifth lens 50, which serves to filter light and provide protection. Table 4 shows the optical physical parameters of each lens in the optical system provided in this embodiment, including surface type, curvature diameter, thickness, and material. The surface number is assigned according to the order of the surfaces of each lens. For example, "OBJ" represents the object surface, "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, "S4" represents the image-side surface of the second lens 20, and so on. "S11" represents the object-side surface of the flat glass 70, and "S12" represents the image-side surface of the flat glass 70. The radius of curvature represents the degree of curvature of the lens surface. A positive value means that the surface bends towards the image surface, and a negative value means that the surface bends towards the object surface. The thickness represents the central axial distance from the current surface to the next surface. The unit of thickness is millimeters (mm). The refractive index and Abbe number indicate the material properties used in different lenses.

[0106] Among them, the aspherical surface of the third lens 30 satisfies:

[0107]

[0108] Where Z represents the axial sagitta in the Z-direction of the aspherical surface; y represents the distance from a point on the aspherical surface to the optical axis; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; K represents the fitted conic coefficients; and a1, a2, a3, a4, a5, and a6 represent the 2nd, 4th, 6th, 8th, 10th, and 12th order coefficients of the aspherical polynomial, respectively.

[0109] As a feasible embodiment, the aspherical surface parameters of the third lens corresponding to Table 8 are shown in Table 9.

[0110] Table 9. Aspherical surface parameters of the third lens in a fixed-focus lens.

[0111] surface S6 S7 K 44.42 0.3 <![CDATA[a2]]> -1.110E-02 1.746E-03 <![CDATA[a3]]> 2.050E-03 6.227E-04 <![CDATA[a4]]> -3.462E-03 -1.600E-04 <![CDATA[a5]]> 1.406E-03 2.810E-05 <![CDATA[a6]]> -3.486E-04 0

[0112] Where -1.110E-02 represents -1.110 * 10 -2 .

[0113] Figure 14 To and Figure 13 A diagram illustrating the field curvature and distortion of a corresponding prime lens; Figure 15 To and Figure 13 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens; Figure 16 To and Figure 13 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens; by Figures 14-16 It can be seen that, under the premise of small size and small aperture, this embodiment can have stable high and low temperature performance and high imaging quality in the temperature range of -40℃ to 85℃.

[0114] In yet another exemplary embodiment, Figure 17 This is a schematic diagram of another fixed-focus lens provided in an embodiment of the present invention. Table 10 shows the structure of the fixed-focus lens. Figure 17 The specific parameters of each lens in the corresponding fixed-focus lens.

[0115] Table 10: Another parameter design for each lens in a fixed-focus lens.

[0116] Example 5 lower limit upper limit φ1 / φ -0.67 -1.5 0 φ2 / φ 0.14 0.1 0.8 φ3 / φ 0.69 0.1 0.7 φ4 / φ 0.93 0.5 1.2 φ5 / φ -0.81 -1.2 0 TTL / ImgH 3.14 2.2 3.2 D / TTL 0.39 0.1 0.5

[0117] In this embodiment, by reasonably setting the optical power of each lens and the fixed-focus lens, the ratio of the optical aperture D of the first lens 10 to the total optical system length TTL of the fixed-focus lens, D / TTL, is only 0.39, and the ratio of the total optical system length TTL of the fixed-focus lens to the diagonal image height ImgH of the effective imaging area of ​​the fixed-focus lens, TTL / ImgH, is 3.14. Thus, the fixed-focus lens can have high imaging quality over a large field of view while meeting the requirements of miniaturization and small aperture.

[0118] Table 11 shows the design parameters of the surface type, radius of curvature, thickness, and material of each lens in a fixed-focus lens corresponding to Table 10.

[0119] Table 11 Another design parameter for each lens in a fixed-focus lens

[0120] Face number Face type radius / mm Thickness / mm Refractive index Abbe number OBJ surface Infinity 2000 S1 spherical 14.68 1.09 1.57 56 S2 spherical 2.34 0.99 S3 spherical 11.36 1.83 1.98 25.5 S4 spherical 77.63 0.12 S5 Aperture Infinity 1.19 S6 aspherical -12 2.47 1.7 63.6 S7 aspherical -2.87 0.17 S8 spherical 25.85 1.98 1.95 32.3 S9 spherical -3.89 0.48 1.92 18.9 S10 spherical Infinity 0.3 S11 spherical Infinity 0.6 1.52 64.2 S12 spherical Infinity 4.3

[0121] refer to Figure 17 The optical system provided in this embodiment includes a first lens 10 with negative optical power, a second lens 20 with positive optical power, a third lens 30 with positive optical power, a fourth lens 40 with positive optical power, and a fifth lens 50 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. The first lens 10, second lens 20, fourth lens 40, and fifth lens 50 are all spherical glass lenses, and the third lens 30 is a glass aspherical lens. Furthermore, an aperture stop 60 is provided in the optical path between the second lens 20 and the third lens 30, and a flat glass plate 70 can be provided between the image plane and the fifth lens 50, which serves to filter light and provide protection. Table 4 shows the optical physical parameters of each lens in the optical system provided in this embodiment, including surface type, curvature diameter, thickness, and material. The surface number is assigned according to the order of the surfaces of each lens. For example, "OBJ" represents the object surface, "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, "S4" represents the image-side surface of the second lens 20, and so on. "S11" represents the object-side surface of the flat glass 70, and "S12" represents the image-side surface of the flat glass 70. The radius of curvature represents the degree of curvature of the lens surface. A positive value means that the surface bends towards the image surface, and a negative value means that the surface bends towards the object surface. The thickness represents the central axial distance from the current surface to the next surface. The unit of thickness is millimeters (mm). The refractive index and Abbe number indicate the material properties used in different lenses.

[0122] Among them, the aspherical surface of the third lens 30 satisfies:

[0123]

[0124] Where Z represents the axial sagitta in the Z-direction of the aspherical surface; y represents the distance from a point on the aspherical surface to the optical axis; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; K represents the fitted conic coefficients; and a1, a2, a3, a4, a5, and a6 represent the 2nd, 4th, 6th, 8th, 10th, and 12th order coefficients of the aspherical polynomial, respectively.

[0125] As a feasible embodiment, the aspherical surface parameters of the third lens corresponding to Table 11 are shown in Table 12.

[0126] Table 12 Aspherical surface parameters of the third lens in another type of fixed-focus lens

[0127] surface S6 S7 K 35.68 0.33 <![CDATA[a2]]> -1.200E-02 1.682E-03 <![CDATA[a3]]> 3.745E-03 4.664E-04 <![CDATA[a4]]> -4.876E-03 -1.170E-04 <![CDATA[a5]]> 2.032E-03 2.289E-05 <![CDATA[a6]]> -4.329E-04 0.000E+00

[0128] Where -1.200E-02 represents -1.200 * 10 -2 .

[0129] Figure 18 To and Figure 17 A diagram illustrating the field curvature and distortion of a corresponding prime lens; Figure 19 To and Figure 17 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens; Figure 20 To and Figure 17 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens; by Figures 18-20 It can be seen that, under the premise of small size and small aperture, this embodiment can have stable high and low temperature performance and high imaging quality in the temperature range of -40℃ to 85℃.

[0130] As an exemplary embodiment, Figure 21 This is a schematic diagram of another fixed-focus lens provided in an embodiment of the present invention. Table 13 shows the structure of the lens. Figure 21 The specific parameters of each lens in the corresponding fixed-focus lens.

[0131] Table 13: Another parameter design for each lens in a fixed-focus lens.

[0132] Example 6 lower limit upper limit φ1 / φ -0.67 -1.5 0 φ2 / φ 0.14 0.1 0.8 φ3 / φ 0.67 0.1 0.7 φ4 / φ 1.07 0.5 1.2 φ5 / φ -0.95 -1.2 0 TTL / ImgH 3.14 2.2 3.2 D / TTL 0.36 0.1 0.5

[0133] In this embodiment, by reasonably setting the optical power of each lens and the fixed-focus lens, the ratio of the optical aperture D of the first lens 10 to the total optical system length TTL of the fixed-focus lens, D / TTL, is only 0.36, and the ratio of the total optical system length TTL of the fixed-focus lens to the diagonal image height ImgH of the effective imaging area of ​​the fixed-focus lens, TTL / ImgH, is 3.14. Thus, the fixed-focus lens can have high imaging quality over a large field of view while meeting the requirements of miniaturization and small aperture.

[0134] Table 14 shows the design parameters of the surface type, radius of curvature, thickness, and material of each lens in a fixed-focus lens corresponding to Table 13.

[0135] Table 14. Another design parameter for each lens in a fixed-focus lens.

[0136] Face number Face type radius / mm Thickness / mm Refractive index Abbe number OBJ surface Infinity 2000 S1 spherical 9.04 1.09 1.57 56 S2 spherical 2.16 1.18 S3 spherical 51.64 1.6 2 25.5 S4 spherical -42 0.5 S5 Aperture Infinity 1.17 S6 aspherical -11.87 2.02 1.61 63.8 S7 aspherical -2.55 0.17 S8 spherical 23.91 1.91 1.9 37.4 S9 spherical -3.04 0.48 1.85 23.8 S10 spherical 113.68 0.3 S11 spherical Infinity 0.6 1.52 64.2 S12 spherical Infinity 4.06

[0137] refer to Figure 21The optical system provided in this embodiment includes a first lens 10 with negative optical power, a second lens 20 with positive optical power, a third lens 30 with positive optical power, a fourth lens 40 with positive optical power, and a fifth lens 50 with negative optical power, arranged sequentially along the optical axis from the object plane to the image plane. The first lens 10, second lens 20, fourth lens 40, and fifth lens 50 are all spherical glass lenses, and the third lens 30 is a glass aspherical lens. Furthermore, an aperture stop 60 is provided in the optical path between the second lens 20 and the third lens 30, and a flat glass plate 70 can be provided between the image plane and the fifth lens 50, which serves to filter light and provide protection. Table 4 shows the optical physical parameters of each lens in the optical system provided in this embodiment, including surface type, curvature diameter, thickness, and material. The surface number is assigned according to the order of the surfaces of each lens. For example, "OBJ" represents the object surface, "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, "S4" represents the image-side surface of the second lens 20, and so on. "S11" represents the object-side surface of the flat glass 70, and "S12" represents the image-side surface of the flat glass 70. The radius of curvature represents the degree of curvature of the lens surface. A positive value means that the surface bends towards the image surface, and a negative value means that the surface bends towards the object surface. The thickness represents the central axial distance from the current surface to the next surface. The unit of thickness is millimeters (mm). The refractive index and Abbe number indicate the material properties used in different lenses.

[0138] Among them, the aspherical surface of the third lens 30 satisfies:

[0139]

[0140] Where Z represents the axial sagitta in the Z-direction of the aspherical surface; y represents the distance from a point on the aspherical surface to the optical axis; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; K represents the fitted conic coefficients; and a1, a2, a3, a4, a5, and a6 represent the 2nd, 4th, 6th, 8th, 10th, and 12th order coefficients of the aspherical polynomial, respectively.

[0141] As a feasible embodiment, the aspherical surface parameters of the third lens corresponding to Table 14 are shown in Table 15.

[0142] Table 15 shows the aspherical surface parameters of the third lens in another type of fixed-focus lens.

[0143] surface S6 S7 K 25 0.27 <![CDATA[a2]]> -1.460E-02 4.652E-03 <![CDATA[a3]]> 1.070E-03 1.668E-03 <![CDATA[a4]]> -4.053E-03 -4.970E-04 <![CDATA[a5]]> 2.077E-03 7.011E-05 <![CDATA[a6]]> -5.980E-04 0

[0144] Where -1.460E-02 represents -1.460 * 10 -2 .

[0145] Figure 22 To and Figure 21 A diagram illustrating the field curvature and distortion of a corresponding prime lens; Figure 23 To and Figure 21 A schematic diagram of the vertical aberration of a corresponding fixed-focus lens; Figure 24 To and Figure 21 A schematic diagram of a Ray Fan corresponding to a fixed-focus lens; by Figures 18-20 It can be seen that, under the premise of small size and small aperture, this embodiment can have stable high and low temperature performance and high imaging quality in the temperature range of -40℃ to 85℃.

[0146] Based on the same inventive concept, embodiments of the present invention also provide a vehicle-mounted camera, which includes a fixed-focus lens provided in any embodiment of the present invention. Therefore, the vehicle-mounted camera provided in the embodiments of the present invention possesses the technical features of the fixed-focus lens provided in the embodiments of the present invention, and can achieve the beneficial effects of the fixed-focus lens provided in the embodiments of the present invention. Similarities can be found in the above description of the fixed-focus lens provided in the embodiments of the present invention, and will not be repeated here.

[0147] It should be understood that the various structures shown above can be used to rearrange, add, or delete modules, units, etc. For example, the structures described in this invention can exist in parallel or some or all of them, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0148] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A fixed focus lens characterized by, Comprise: a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in order along an optical axis from an object plane to an image plane; the first lens has a negative optical power, the second lens has a positive optical power, the third lens has a positive optical power, the fourth lens has a positive optical power, and the fifth lens has a negative optical power; wherein the optical aperture D of the first lens and the total length of the optical system TTL of the fixed focus lens satisfy: 0.1≤D / TTL≤0.5; the fourth lens and the fifth lens are cemented lenses; the refractive index of the fourth lens is n4, and the refractive index of the fifth lens is n5; wherein 0.85≤n4 / n5≤1.15; the fixed focus lens is composed of five lenses with optical power.

2. The fixed focus lens of claim 1, wherein The first lens, the second lens, the third lens, the fourth lens and the fifth lens are all glass spherical lenses.

3. The fixed focus lens of claim 1, wherein The first lens, the second lens, the fourth lens and the fifth lens are all glass spherical lenses; and the third lens is a glass aspherical lens.

4. The fixed focus lens of claim 1, wherein, The optical power of the first lens is φ1, the optical power of the second lens is φ2, the optical power of the third lens is φ3, the optical power of the fourth lens is φ4, the optical power of the fifth lens is φ5, and the optical power of the fixed focus lens is φ; wherein -1.5≤φ1 / φ≤0, 0.1≤φ2 / φ≤0.8, 0.1≤φ3 / φ≤0.7, 0.5≤φ4 / φ≤1.2, and -1.2≤φ5 / φ≤0.

5. The fixed focus lens of claim 1, wherein Further comprise: a diaphragm; the diaphragm is located in the optical path between the second lens and the third lens.

6. The fixed focus lens of claim 1, wherein, The Abbe number Vd4 of the fourth lens is in the range of 31 7. The fixed focus lens of claim 1, wherein, The diagonal image height of the effective imaging area of the image plane of the fixed focus lens is ImgH; wherein 2.2≤TTL / ImgH≤3.

2.

8. A vehicle camera, characterized by, Comprise: the fixed focus lens of any one of claims 1-7.

Images