Optical lens

Abstract

The present invention provides an optical lens, which has a total of six lenses, and includes in order from the object side to the imaging surface along the optical axis: a first lens with negative optical power, whose image side surface is concave; a second lens with negative optical power, whose object side surface is convex and whose image side surface is concave; a third lens with positive optical power, whose image side surface is convex; a fourth lens with negative optical power, whose object side surface and image side surface are both concave; a fifth lens with positive optical power, whose object side surface is convex and whose image side surface is concave; a sixth lens with positive optical power, whose object side surface is convex and whose image side surface is concave. The optical lens provided by the present invention has one or more advantages such as large aperture, large field of view, high imaging quality, etc. through specific surface shape matching and reasonable optical power distribution.

Description

Technical Field

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

[0002] As intelligent driving gradually improves, vehicle-mounted cameras, as the "eyes of autonomous driving", are the core sensor devices. The development of vehicle-mounted cameras has gradually extended from early use for driving records, reversing images, and parking surrounds to behavior recognition in intelligent cockpits and ADAS assisted driving.

[0003] As an extension of the driver monitoring system DMS, the in-cabin monitoring system OMS can not only monitor the driver's status and remind the driver of dangerous behaviors such as fatigue driving, smoking, and making phone calls, but also monitor the behavior of other passengers in the car, including whether children are left in the car, and whether there are objects left in the car. However, the existing OMS lens has a small field of view and low imaging quality, and cannot monitor the status of the driver and passengers well. Summary of the invention

[0004] In view of the above problems, an object of the present invention is to provide an optical lens having the advantage of excellent imaging quality.

[0005] The technical solution adopted by the present invention is:

[0006] An optical lens, comprising six lenses, which include:

[0007] A first lens having negative optical power, whose image side surface is concave;

[0008] The second lens has a negative optical power, its object side surface is convex, and its image side surface is concave;

[0009] A third lens element having positive refractive power and a convex image-side surface;

[0010] The fourth lens element has negative optical power, and both the object side surface and the image side surface are concave;

[0011] a fifth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is concave;

[0012] a sixth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is concave;

[0013] The curvature radius R9 of the object side surface of the fifth lens and the curvature radius R10 of the image side surface of the fifth lens satisfy: -0.9<(R9-R10) / (R9+R10)<-0.1.

[0014] Further preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4.7 < IH / EPD < 5.4.

[0015] Further preferably, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: f5 / f > 8; the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 0.1 < R9 / R10 < 0.9.

[0016] Further preferably, the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens and the effective focal length f of the optical lens satisfy: 2.7 < f456 / f < 10.5.

[0017] Further preferably, the radius of curvature R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: R3 / f > 3.6; the radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -29 < R7 / f < -3.5.

[0018] Further preferably, the radius of curvature R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 2 < R4 / f < 3.7; the radius of curvature R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 1.5 < R12 / f < 2.4.

[0019] Further preferably, the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: R10 / f > 10; the sagittal height Sag10 of the image side surface clear aperture of the fifth lens and the clear aperture diameter d10 of the image side surface of the fifth lens satisfy: -0.15 < Sag10 / d10 < 0.15.

[0020] Further preferably, the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 0.1 < R3 / R10 < 3.1; the radius of curvature R10 of the image side surface of the fifth lens and the focal length f5 of the fifth lens satisfy: 0.1 < R10 / f5 < 2.8.

[0021] Further preferably, the radius of curvature R8 of the image side surface of the fourth lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: (R8 + R9) / (R8 - R9) > 1; the distance CT45 between the fourth lens and the fifth lens on the optical axis and the central thickness CT5 of the fifth lens along the optical axis satisfy: 12 < CT5 / CT45 < 39.

[0022] More preferably, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 8 < f5 / f < 210; the radius of curvature R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 3.6 < R3 / f < 35; the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 10 < R10 / f < 45; the radius of curvature R8 of the image side surface of the fourth lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: 1 < (R8 + R9) / (R8 - R9) < 380.

[0023] The optical lens provided by the present invention adopts six lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and enable the lens to have one or more advantages such as a large aperture, a large field of view angle, and high imaging quality. Brief Description of the Drawings

[0024] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0025] Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0026] Figure 2 is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0027] Figure 3 is an F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 4 is an axial aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 5 is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 6 is an MTF curve diagram of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 7 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 8 is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0033] Fig. 9 is an F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 2 of the present invention.

[0034] Fig.10 Graph showing the axial aberration of the optical lens in Embodiment 2 of the present invention.

[0035] Fig.11 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0036] Fig.12 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0037] Fig.13 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0038] Fig.14 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0039] Fig.15 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 3 of the present invention.

[0040] Fig.16 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0041] Fig.17 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0042] Fig.18 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0043] Fig.19 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0044] Fig. 20 It is a field curvature curve diagram of the optical lens in Example 4 of the present invention.

[0045] Fig.21 4 is a F-Tan (Theta) distortion curve of the optical lens in Example 4 of the present invention.

[0046] Fig. 22 4 is an axial aberration curve diagram of the optical lens in Example 4 of the present invention.

[0047] Fig.23 Graph showing the vertical axis chromatic aberration of the optical lens in Example 4 of the present invention.

[0048] Fig.24 This is the MTF curve diagram of the optical lens in Example 4 of the present invention.

[0049] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0050] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0051] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0052] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0053] In this article, the near optical axis refers to the area near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least at the near optical axis; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least at the near optical axis. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0054] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0055] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0056] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0057] The optical lens provided by the embodiment of the present invention is composed of six lenses, which are a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens in order from the object side to the imaging surface along the optical axis.

[0058] In some embodiments, the first lens may have a negative optical power, its object side surface is convex or concave, and its image side surface is concave. The second lens may have a negative optical power, its object side surface is convex, and its image side surface is concave. The third lens may have a positive optical power, its object side surface may be concave or convex, and its image side surface is convex. The fourth lens may have a negative optical power, and both its object side surface and image side surface are concave. The fifth lens may have a positive optical power, its object side surface is convex, and its image side surface is concave. The sixth lens may have a positive optical power, its object side surface is convex, and its image side surface is concave.

[0059] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the third lens and the fourth lens. It is understandable that the aperture can be used to limit the amount of light entering to change the brightness of the image. In addition, when the aperture is located between the third lens and the fourth lens, the aperture can reasonably distribute the effects of the first lens to the sixth lens. For example, the first lens, the second lens, and the third lens can be used to receive light to a greater extent, and the fourth lens to the sixth lens can be used to correct the aberration, which is beneficial to balance the structure of the entire optical system. In addition, when the aperture is located between the third lens and the fourth lens, it is convenient to correct the aperture aberration.

[0060] In some embodiments, the optical lens may further include a filter and a protective glass, and the filter and the protective glass may be sequentially arranged between the sixth lens and the imaging surface along the optical axis. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass plays a role in protecting the optical lens, preventing the photosensitive chip from being damaged, and can improve the impact resistance and scratch resistance of the optical lens, while having almost no effect on the imaging quality of the optical lens.

[0061] In some embodiments, the radius of curvature R9 of the object side of the fifth lens and the radius of curvature R10 of the image side of the fifth lens satisfy: -0.9<(R9-R10) / (R9+R10)<-0.1. Meeting the above range and reasonably limiting the shapes of the object side and image side of the fifth lens can effectively reduce the field curvature and aberration of the optical lens and improve the imaging quality. Preferably, -0.71<(R9-R10) / (R9+R10)<-0.15.

[0062] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4.7 < IH / EPD < 5.4. By reasonably controlling the true image height and the entrance pupil diameter corresponding to the maximum field of view angle of the optical lens within the above range, the width of the light beam incident on the optical lens can be increased, so that the brightness at the image plane of the optical lens is improved to avoid vignetting, and the optical lens has the characteristic of a large image plane, thereby improving the imaging quality. Preferably, 4.85 < IH / EPD < 5.06.

[0063] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: f5 / f > 8; the radius of curvature R9 of the object side surface of the fifth lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 0.1 < R9 / R10 < 0.9. By reasonably limiting the ratio of the focal length of the fifth lens and the shapes of the object side surface and the image side surface of the fifth lens within the above range, the angle of incidence of the marginal field of view on the imaging plane can be suppressed, and more light beams can be effectively transmitted to the imaging plane, thereby improving the imaging quality. Further, 8 < f5 / f < 210. Preferably, 9.17 < f5 / f < 199.22, 0.16 < R9 / R10 < 0.74.

[0064] In some embodiments, the combined focal length f456 of the fourth lens, the fifth lens and the sixth lens and the effective focal length f of the optical lens satisfy: 2.7 < f456 / f < 10.5. By reasonably controlling the ratio of the focal length of the rear lens group of the optical lens within the above range, the light trend can be reasonably controlled, and the imaging stability of the optical lens can be improved. Preferably, 2.97 < f456 / f < 9.67.

[0065] In some embodiments, the radius of curvature R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: R3 / f > 3.6; the radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -29 < R7 / f < -3.5. By reasonably restricting the shapes of the object side surface of the second lens and the object side surface of the fourth lens within the above range, it helps to control distortion and improve the resolution of the optical lens. Further, 3.6 < R3 / f < 35. Preferably, 3.98 < R3 / f < 33.18, -27.09 < R7 / f < -4.05.

[0066] In some embodiments, the radius of curvature R4 of the image side surface of the second lens and the effective focal length f of the optical lens satisfy: 2 < R4 / f < 3.7; the radius of curvature R12 of the image side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 1.5 < R12 / f < 2.4. By satisfying the above ranges and reasonably defining the shapes of the image side surfaces of the second lens and the sixth lens, it is beneficial to correct the spherical aberration of the optical lens and improve the imaging quality of the optical lens. Preferably, 2.28 < R4 / f < 3.39, 1.6 < R12 / f < 2.17.

[0067] In some embodiments, the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: R10 / f > 10; the sagittal height Sag10 of the clear aperture of the image side surface of the fifth lens and the clear aperture diameter d10 of the image side surface of the fifth lens satisfy: -0.15 < Sag10 / d10 < 0.15. By satisfying the above ranges and reasonably defining the shape of the image side surface of the fifth lens, it is possible to improve the field curvature of the lens, reduce the difficulty of optimizing lens aberrations, and thus improve the imaging quality of the lens. Further, 10 < R10 / f < 45. Preferably, 11.55 < R10 / f < 40.64, -0.1 < Sag10 / d10 < 0.04.

[0068] In some embodiments, the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R10 of the image side surface of the fifth lens satisfy: 0.1 < R3 / R10 < 3.1; the radius of curvature R10 of the image side surface of the fifth lens and the focal length f5 of the fifth lens satisfy: 0.1 < R10 / f5 < 2.8. By satisfying the above ranges and reasonably defining the radius of curvature of the object side surface of the second lens, the radius of curvature of the image side surface of the fifth lens, and the focal length of the fifth lens, it is helpful to converge light, reduce the light deflection angle, and make the light path stable. Preferably, 0.16 < R3 / R10 < 2.88, 0.19 < R10 / f5 < 2.59.

[0069] In some embodiments, the radius of curvature R8 of the image side surface of the fourth lens and the radius of curvature R9 of the object side surface of the fifth lens satisfy: (R8 + R9) / (R8 - R9) > 1; the distance CT45 between the fourth lens and the fifth lens on the optical axis and the central thickness CT5 of the fifth lens along the optical axis satisfy: 12 < CT5 / CT45 < 39. By satisfying the above ranges and reasonably controlling the shapes of the image side surface of the fourth lens and the object side surface of the fifth lens, the distance between the fourth lens and the fifth lens on the optical axis, and the central thickness of the fifth lens along the optical axis, it is possible to maintain good processability of the lens and reasonable arrangement within the system. Further, 1 < (R8 + R9) / (R8 - R9) < 380. Preferably, 1.19 < (R8 + R9) / (R8 - R9) < 342.63, 13.36 < CT5 / CT45 < 35.56.

[0070] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.8 < TTL / f < 7.8, and the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 2.5 < TTL / IH < 3.1. By reasonably limiting the total optical length TTL, the effective focal length f, and the true image height IH corresponding to the maximum field of view angle of the optical lens within the above ranges, the optical lens has sufficient space to arrange each lens and has the characteristic of a large image plane. Preferably, 6.26 < TTL / f < 7.58, 2.57 < TTL / IH < 3.01.

[0071] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1 < BFL / f < 1.3. By reasonably limiting the back focal length of the optical lens within the above range, the design and assembly difficulty of the optical lens is reduced, and the yield is improved. Preferably, 1.02 < BFL / f < 1.24.

[0072] In some embodiments, the maximum field of view angle FOV of the optical lens, the effective focal length f of the optical lens, and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 50° < FOV × f / IH < 65°. By reasonably limiting the maximum field of view angle, the effective focal length, and the true image height of the optical lens within the appropriate ranges, it helps the optical lens to have the characteristics of a large field of view angle and a large image height. Preferably, 56.27° < FOV × f / IH < 58.48°.

[0073] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -2.8 < f1 / f < -1.1. By reasonably limiting the proportion of the focal length of the first lens within the above range, it helps to collect light rays with a large field of view angle and increase the field of view angle of the optical lens. Preferably, -2.57 < f1 / f < -1.3.

[0074] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -19.3 < f2 / f < -4.2. By reasonably limiting the proportion of the focal length of the second lens within the above range, it helps to share the negative optical power of the front-end lens and reduce the difficulty of chromatic aberration correction for the subsequent lenses. Preferably, -17.65 < f2 / f < -4.67.

[0075] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 1.1 < f3 / f < 2.2. By reasonably limiting the proportion of the focal length of the third lens within the above range, the difficulty of aberration and field curvature correction for the subsequent lenses can be effectively reduced. Preferably, 1.3 < f3 / f < 2.01.

[0076] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -26.7 < f4 / f < -5.2. Meeting the above range, by reasonably defining the proportion of the focal length of the fourth lens, it is beneficial to the smooth trend of light rays, reduce the deflection angle of marginal rays, and reduce the difficulty of subsequent lens aberration correction. Preferably, -24.28 < f4 / f < -5.76.

[0077] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 2.7 < f6 / f < 4.5. Meeting the above range, by reasonably defining the proportion of the focal length of the sixth lens, it helps to suppress the angle of incidence of marginal fields on the imaging surface, effectively transmit more light beams to the imaging surface, and improve the imaging quality. Preferably, 3.07 < f6 / f < 4.17.

[0078] In some embodiments, the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: (R5 + R6) / (R5 - R6) > 0.8. Meeting the above range, by reasonably defining the shapes of the object side surface and the image side surface of the third lens, it helps to control the trend of marginal field light beams to increase the image height and reduce the off-axis aberration of the optical lens. Further, 0.8 < (R5 + R6) / (R5 - R6) < 45. Preferably, 0.81 < (R5 + R6) / (R5 - R6) < 42.03.

[0079] In some embodiments, the curvature radius R10 of the image side surface of the fifth lens and the curvature radius R11 of the object side surface of the sixth lens satisfy: 1 < (R10 + R11) / (R10 - R11) < 1.3. Meeting the above range, by reasonably defining the shapes of the image side surface of the fifth lens and the object side surface of the sixth lens, it can effectively improve the imaging quality of the marginal field and improve the image quality. Preferably, 1.05 < (R10 + R11) / (R10 - R11) < 1.22.

[0080] In some embodiments, the overall optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis satisfy: 0.5 < ∑CT / TTL < 0.8. Meeting the above range, it helps to achieve high pixel characteristics and improve the imaging quality of the optical lens. Preferably, 0.51 < ∑CT / TTL < 0.69.

[0081] In some embodiments, the clear aperture radius d1 of the object side surface of the first lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.4 < d1 / (IH / 2) / tan(FOV / 2) < 0.7. By satisfying the above range, by reasonably defining the front port diameter, true image height, and maximum field of view angle of the optical lens, the overall geometric shape of the optical lens can be reasonably arranged, improving its structural stability. Preferably, 0.43 < d1 / (IH / 2) / tan(FOV / 2) < 0.6.

[0082] In some embodiments, the optical lens satisfies the following conditional expressions: 1.4 mm < f < 1.8 mm; 140° < FOV < 150°; 0.7 mm < EPD < 0.9 mm; 9 mm < TTL < 13.5 mm; 1.8 < FNO < 2.2; 3.6 mm < IH < 4.4 mm; 21.4° < CRA < 28.3°; 1.5 < BFL < 2.1 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the overall optical length of the optical lens, FNO represents the f-number of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the principal ray incident angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. By satisfying the above range, the optical lens has at least one or more advantages such as a large target surface, a large aperture, and a large field of view angle. Preferably, 1.58 mm < f < 1.66 mm; 141° < FOV < 143°; 0.78 mm < EPD < 0.83 mm; 10.33 mm < TTL < 12.01 mm; 1.9 < FNO < 2.1; 3.9 mm < IH < 4.1 mm; 23.71° < CRA < 25.84°; 1.69 < BFL < 1.96 mm.

[0083] In some embodiments, the lens material in the optical lens provided by the present invention may be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. Additionally, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected due to the low dispersion characteristic of the glass itself. More specifically, the first lens and the third lens in the optical lens provided by the present invention may be glass lenses, and the second lens, the fourth lens, the fifth lens, and the sixth lens may be plastic lenses.

[0084] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens may be spherical lenses or aspherical lenses. Compared with spherical structures, aspherical structures can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and reducing the size of lenses, and better realizing miniaturization of lenses. More specifically, the first lens and the third lens of the present invention are spherical lenses, and the second lens, the fourth lens, the fifth lens, and the sixth lens are aspherical lenses.

[0085] In various embodiments of the present invention, when the lens is an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations:

[0086] ;

[0087] Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients respectively.

[0088] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0089] Example 1

[0090] See also Figure 1 , which is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention, wherein the optical lens 100 includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a filter G1 and a protective glass G2.

[0091] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0092] The second lens L2 has negative refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave;

[0093] The third lens L3 has positive refractive power, and its object-side surface S5 and image-side surface S6 are both convex;

[0094] The fourth lens L4 has negative refractive power, and its object-side surface S7 and image-side surface S8 are both concave;

[0095] The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave;

[0096] The sixth lens L6 has positive refractive power, its object-side surface S11 is convex, and its image-side surface S12 is concave;

[0097] The object side surface S13 and the image side surface S14 of the filter G1 are both planes;

[0098] The object side surface S15 and the image side surface S16 of the protective glass G2 are both flat surfaces;

[0099] The imaging surface S17 is a plane.

[0100] The first lens L1 and the third lens L3 are glass spherical lenses, and the second lens L2, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are plastic aspherical lenses.

[0101] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0102] Table 1-1

[0103]

[0104] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0105] Table 1-2

[0106]

[0107] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve and MTF curve of the optical lens 100 are respectively as follows: Figures 2 to 6 shown.

[0108] Figure 2 The field curvature curve of Example 1 is shown, which indicates the degree of curvature of light of different wavelengths on the meridional image plane and the sagittal image plane, the horizontal axis indicates the offset (unit: mm), and the vertical axis indicates the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.02mm~0.08mm, indicating that the optical lens can correct the field curvature well.

[0109] Figure 3The F-Tan (Theta) distortion curve of Example 1 is shown, which represents the F-Tan (Theta) distortion of light of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-Tan (Theta) distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the F-Tan (Theta) distortion of the optical lens is controlled within -60%~0, the image compression in the edge angle area is relatively gentle, and the clarity of the expanded image is effectively improved.

[0110] Figure 4 The axial aberration curve of Example 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the offset of the axial aberration is controlled within -0.02mm~0.02mm, indicating that the optical lens can correct the axial aberration well.

[0111] Figure 5 The vertical chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.940 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2 μm~2 μm, indicating that the optical lens can perfectly correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0112] Figure 6 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value of this embodiment is above 0.3 in the whole field of view, and in the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability under normal temperature.

[0113] Example 2

[0114] See also Figure 7 , shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0115] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0116] Table 2-1

[0117]

[0118] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0119] Table 2-2

[0120]

[0121] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve, and MTF curve of the optical lens 200 are shown as follows: Figures 8 to 12 As shown. Figure 8 It can be seen from the figure that the field curvature of the meridian image plane and the sagittal image plane is controlled within -0.04mm~0.02mm, indicating that the optical lens 200 can correct the field curvature well. Fig. 9 It can be seen that the F-Tan (Theta) distortion of the optical lens 200 is controlled within -60% to 0, and the image compression in the edge angle area is relatively gentle, which effectively improves the clarity of the expanded image. Fig.10 It can be seen from the figure that the offset of the axial aberration in this embodiment is controlled within -0.01mm~0.02mm, indicating that the optical lens can correct the axial aberration well. Fig.11 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2μm~3μm, indicating that the optical lens can well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane. Fig.12 It can be seen that the MTF value of this embodiment is above 0.4 in the whole field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, with good imaging quality and good detail resolution.

[0122] Example 3

[0123] See also Fig.13 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0124] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0125] Table 3-1

[0126]

[0127] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0128] Table 3-2

[0129]

[0130] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve, and MTF curve of the optical lens 300 are shown as follows: Figures 14 to 18 As shown. Fig.14 It can be seen from the figure that the field curvature of the meridian image plane and the sagittal image plane is controlled within -0.04mm~0.04mm, indicating that the optical lens 300 can correct the field curvature well. Fig.15 It can be seen that the F-Tan (Theta) distortion of the optical lens 300 is controlled within -60% to 0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image. Fig.16 It can be seen from the figure that the offset of the axial aberration in this embodiment is controlled within -0.01mm~0.03mm, indicating that the optical lens can correct the axial aberration well. Fig.17 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -3μm~4μm, indicating that the optical lens can well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane. Fig.18 It can be seen that the MTF value of this embodiment is above 0.4 in the whole field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, with good imaging quality and good detail resolution.

[0131] Example 4

[0132] See also Fig.19 , shown is a schematic diagram of the structure of an optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0133] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0134] Table 4-1

[0135]

[0136] The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0137] Table 4-2

[0138]

[0139] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, vertical chromatic aberration curve, and MTF curve of the optical lens 400 are shown as follows: Figure 20 to Figure 24 As shown. Fig. 20 It can be seen from the figure that the field curvature of the meridian image plane and the sagittal image plane is controlled within -0.02mm~0.03mm, indicating that the optical lens 400 can correct the field curvature well. Fig.21 It can be seen that the F-Tan (Theta) distortion of the optical lens 400 is controlled within -60% to 0, and the image compression in the edge angle area is relatively smooth, which effectively improves the clarity of the expanded image. Fig. 22 It can be seen from the figure that the offset of the axial aberration in this embodiment is controlled within -0.01mm~0.02mm, indicating that the optical lens can correct the axial aberration well. Fig.23 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2μm~2μm, indicating that the optical lens can perfectly correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane. Fig.24 It can be seen that the MTF value of this embodiment is above 0.4 in the whole field of view. In the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, with good imaging quality and good detail resolution.

[0140] Please refer to Table 5-1 and Table 5-2, which are the optical characteristics corresponding to the above-mentioned embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value FNO, the real image height IH corresponding to the maximum field of view angle, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0141] Table 5-1

[0142]

[0143] Table 5-2

[0144]

[0145] In summary of the above embodiments, the optical lens provided by the present invention adopts six lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it is possible to improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as large aperture, large field of view, and high imaging quality.

[0146] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0147] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, comprising six lenses, characterized in that: It sequentially includes, from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose image side is concave; A second lens with negative optical power, whose object side is convex and whose image side is concave; A third lens with positive optical power, whose image side is convex; A fourth lens with negative optical power, whose object side and image side are both concave; A fifth lens with positive optical power, whose object side is convex and whose image side is concave; A sixth lens with positive optical power, whose object side is convex and whose image side is concave; Wherein, the radius of curvature R9 of the object side of the fifth lens and the radius of curvature R10 of the image side of the fifth lens satisfy: -0.9 < (R9 - R10) / (R9 + R10) < -0.1; the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4.7 < IH / EPD < 5.

4.

2. The optical lens according to claim 1, characterized in that: The maximum field of view angle FOV of the optical lens, the effective focal length f of the optical lens, and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 50° < FOV×f / IH < 65°.

3. The optical lens according to claim 1, characterized in that: The focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: f5 / f > 8; the radius of curvature R9 of the object side of the fifth lens and the radius of curvature R10 of the image side of the fifth lens satisfy: 0.1 < R9 / R10 < 0.

9.

4. The optical lens according to claim 1, characterized in that: The combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens and the effective focal length f of the optical lens satisfy: 2.7 < f456 / f < 10.

5.

5. The optical lens according to claim 1, characterized in that: The radius of curvature R3 of the object side of the second lens and the effective focal length f of the optical lens satisfy: R3 / f > 3.6; the radius of curvature R7 of the object side of the fourth lens and the effective focal length f of the optical lens satisfy: -29 < R7 / f < -3.

5.

6. The optical lens according to claim 1, characterized in that: The radius of curvature R4 of the image side of the second lens and the effective focal length f of the optical lens satisfy: 2 < R4 / f < 3.7; the radius of curvature R12 of the image side of the sixth lens and the effective focal length f of the optical lens satisfy: 1.5 < R12 / f < 2.

4.

7. The optical lens according to claim 1, characterized in that: The radius of curvature R10 of the image side of the fifth lens and the effective focal length f of the optical lens satisfy: R10 / f > 10; the sagittal height Sag10 of the image side clear aperture of the fifth lens and the image side clear aperture diameter d10 of the fifth lens satisfy: -0.15 < Sag10 / d10 < 0.

15.

8. The optical lens according to claim 1, characterized in that: The radius of curvature R3 of the object side of the second lens and the radius of curvature R10 of the image side of the fifth lens satisfy: 0.1 < R3 / R10 < 3.1; the radius of curvature R10 of the image side of the fifth lens and the focal length f5 of the fifth lens satisfy: 0.1 < R10 / f5 < 2.

8.

9. The optical lens according to claim 1, characterized in that: The radius of curvature R8 of the image side of the fourth lens and the radius of curvature R9 of the object side of the fifth lens satisfy: (R8 + R9) / (R8 - R9) > 1; the distance CT45 between the fourth lens and the fifth lens on the optical axis and the central thickness CT5 of the fifth lens along the optical axis satisfy: 12 < CT5 / CT45 < 39.

10. The optical lens according to claim 1, characterized in that: The focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 8 < f5 / f < 210; the curvature radius R3 of the object side surface of the second lens and the effective focal length f of the optical lens satisfy: 3.6 < R3 / f < 35; the curvature radius R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 10 < R10 / f < 45; the curvature radius R8 of the image side surface of the fourth lens and the curvature radius R9 of the object side surface of the fifth lens satisfy: 1 < (R8 + R9) / (R8 - R9) < 380.

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