Optical lens

Abstract

The application provides an optical lens, which has seven lenses with optical power, and sequentially comprises, along an optical axis from an object side to an imaging surface, a first lens with negative optical power, whose object side surface is a convex surface and whose image side surface is a concave surface; a second lens with negative optical power, whose object side surface is a concave surface and whose image side surface is a convex surface; a third lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a convex surface; a fourth lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a convex surface; a fifth lens with negative optical power, whose object side surface is a concave surface and whose image side surface is a concave surface; a sixth lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a convex surface; and a seventh lens with negative optical power, whose object side surface is a convex surface near the optical axis and whose image side surface is a concave surface. The application has one or more advantages, such as a large imaging surface, a large aperture, miniaturization, high imaging quality and the like, by specific surface shape matching and reasonable optical power distribution.

Description

Technical Field

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

[0002] As people's demands for driving experience continue to increase, automotive optical lenses are being used more and more in intelligent driving, and the status of automotive optical lenses in the automotive industry is constantly rising.

[0003] Advanced Driver Assistance Systems (ADAS) play a crucial role in intelligent driving. They use various lenses and sensors to collect environmental information to ensure driver safety. Existing ADAS lenses not only require a slim and compact design with high pixel count and high resolution, but also need to produce clear images in low-light conditions. Therefore, it is necessary to develop an optical lens with excellent imaging performance. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide an optical lens with the advantage of excellent image quality.

[0005] The technical solution adopted in this invention is as follows:

[0006] An optical lens has seven lenses with optical power, arranged sequentially along the optical axis from the object side to the imaging plane:

[0007] The first lens with negative optical power has a convex object side and a concave image side.

[0008] A second lens with negative optical power has a concave object side and a convex image side.

[0009] A third lens with positive optical power has a convex object-side surface and a convex image-side surface.

[0010] The fourth lens with positive optical power has a convex object-side surface and a convex image-side surface.

[0011] The fifth lens with negative optical power has a concave object side and a concave image side.

[0012] The sixth lens with positive optical power has a convex object-side surface and a convex image-side surface.

[0013] The seventh lens with negative optical power has an object-side surface that is convex near the optical axis and an image-side surface that is concave.

[0014] Wherein, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -0.15 <f / f2<-0.05;

[0015] 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: -1.7 < R3 / f < -1.2;

[0016] 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: -2.8 < R4 / f < -1.8. Further preferably, the combined focal length f13 of the first lens, the second lens and the third lens and the combined focal length f47 of the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy: 0.85 < f13 / f47 < 1.2.

[0017] Further preferably, the maximum field angle FOV of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 9° / mm < FOV / IH < 10.5° / mm.

[0018] Further preferably, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.3 < IH / EPD < 2.9.

[0019] Further preferably, the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: -0.45 < (R11 + R12) / (R11 - R12) < -0.15; the radius of curvature R11 of the object side surface of the sixth lens and the focal length f6 of the sixth lens satisfy: 0.6 < R11 / f6 < 0.88; the radius of curvature R12 of the image side surface of the sixth lens and the focal length f6 of the sixth lens satisfy: -1.7 < R12 / f6 < -1.

[0020] Further preferably, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: -6 < f2 / f3 < -3.5; the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: -0.7 < f6 / f7 < -0.44.

[0021] Further preferably, the central thickness CT2 of the second lens and the central thickness CT3 of the third lens satisfy: 1.4 < CT2 / CT3 < 1.8.

[0022] Further preferably, the distance CT34 between the third lens and the fourth lens on the optical axis and the distance CT56 between the fifth lens and the sixth lens on the optical axis and the total optical length TTL of the optical lens satisfy: 0.08 < (CT34 + CT56) / TTL < 0.18.

[0023] Further preferably, the image-side half-aperture sagitta SAG32 of the third lens and the center thickness CT3 of the third lens satisfy: -0.15 <SAG32 / CT3<-0.05。

[0024] Further preferably, the half-aperture DM11 of the object-side surface of the first lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 0.6 <DM11 / IH<0.8。

[0025] The optical lens provided by this invention uses seven lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as large image area, large aperture, miniaturization, weak ghosting, and high imaging quality. Attached Figure Description

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0027] Figure 1 This is a schematic diagram of the optical lens structure in Embodiment 1 of the present invention.

[0028] Figure 2 This is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 3 This is the F-Theta distortion curve of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 4 This is an axial aberration curve of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 5 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 6 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

[0033] Figure 7 This is a relative illumination curve of the optical lens in Embodiment 1 of the present invention.

[0034] Figure 8 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0035] Figure 9 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 10 This is the F-Theta distortion curve of the optical lens in Embodiment 2 of the present invention.

[0037] Figure 11 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0038] Figure 12 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0039] Figure 13 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0040] Figure 14 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0041] Figure 15 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0042] Figure 16 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0043] Figure 17 This is the F-Theta distortion curve of the optical lens in Embodiment 3 of the present invention.

[0044] Figure 18 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0045] Figure 19 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0046] Figure 20 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0047] Figure 21 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0048] Figure 22 This is a schematic diagram of the optical lens structure in Embodiment 4 of the present invention.

[0049] Figure 23 This is a field curvature curve diagram of the optical lens in Embodiment 4 of the present invention.

[0050] Figure 24 This is the F-Theta distortion curve of the optical lens in Embodiment 4 of the present invention.

[0051] Figure 25 This is an axial aberration curve of the optical lens in Embodiment 4 of the present invention.

[0052] Figure 26 This is a chromatic aberration curve of the optical lens in Embodiment 4 of the present invention.

[0053] Figure 27 This is the MTF curve of the optical lens in Embodiment 4 of the present invention.

[0054] Figure 28 This is a relative illumination curve of the optical lens in Embodiment 4 of the present invention.

[0055] Figure 29 This is a schematic diagram of the optical lens structure in Embodiment 5 of the present invention.

[0056] Figure 30 This is a field curvature curve diagram of the optical lens in Embodiment 5 of the present invention.

[0057] Figure 31 This is the F-Theta distortion curve of the optical lens in Embodiment 5 of the present invention.

[0058] Figure 32 This is an axial aberration curve of the optical lens in Embodiment 5 of the present invention.

[0059] Figure 33 This is a chromatic aberration curve of the optical lens in Embodiment 5 of the present invention.

[0060] Figure 34 This is the MTF curve of the optical lens in Embodiment 5 of the present invention.

[0061] Figure 35 This is a relative illumination curve of the optical lens in Embodiment 5 of the present invention.

[0062] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0063] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this 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.

[0064] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0065] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0066] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0067] It should also be understood that the terms "comprising," "including," "having," "containing," 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. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0068] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0069] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0070] The optical lens provided in this embodiment of the invention has seven lenses with optical power, which are arranged sequentially from the object side to the imaging plane along the optical axis as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens.

[0071] In some embodiments, the first lens may have a negative optical power, with its object side being convex and its image side being concave. The second lens may have a negative optical power, with its object side being concave and its image side being convex. The third lens may have a positive optical power, with its object side being convex and its image side being convex. The fourth lens may have a positive optical power, with its object side being convex and its image side being convex. The fifth lens may have a negative optical power, with its object side being concave and its image side being concave. The sixth lens may have a positive optical power, with its object side being convex and its image side being convex. The seventh lens may have a negative optical power, with its object side being convex near the optical axis and its image side being concave.

[0072] In some embodiments, the optical lens may further include an aperture, which may be located between the third lens and the fourth lens. It can be understood that the aperture is used to limit the amount of incident light to change the brightness of the image formation. When the aperture is located between the third lens and the fourth lens, it is convenient for the correction of aperture aberration.

[0073] In some embodiments, the optical lens may further include a protective glass, which is disposed between the seventh lens and the imaging surface. The protective glass plays a role in protecting the optical lens and preventing the photosensitive chip from being damaged.

[0074] In some embodiments, the fourth lens and the fifth lens may be glued together to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens, improving the assembly yield of the optical lens, reducing the light energy loss, and improving the lens transmittance and imaging quality.

[0075] In some embodiments, the second lens may have a concave-convex surface type, and the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -0.12 < f / f2 < -0.05; the radius of curvature R3 of the object side of the second lens and the effective focal length f of the optical lens satisfy -1.7 < R3 / f < -1.2; the radius of curvature R4 of the image side of the second lens and the effective focal length f of the optical lens satisfy -2.8 < R4 / f < -1.8. This makes the second lens have a relatively large negative optical power. At the same time, the object side of the second lens is concave, which is beneficial to receiving the rapidly diverging light emitted by the first lens, enabling the light to smoothly enter the third lens, and thus reducing the sensitivity of the optical lens. The image side of the second lens is convex, which can reduce the incident height of the large-field light, thereby reducing the rear aperture of the lens.

[0076] In some embodiments, the combined focal length f13 of the first lens, the second lens, and the third lens and the combined focal length f47 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: 0.85 < f13 / f47 < 1.2. Reasonably defining the ratio of the optical power of the lens groups before and after the aperture enables the light rays to have a relatively stable trend before and after the aperture, which is beneficial to reducing the system sensitivity. At the same time, it is beneficial to correcting aberrations such as distortion and field curvature of the optical system and improving the imaging quality of the lens.

[0077] In some embodiments, the maximum field angle FOV of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 9° / mm < FOV / IH < 10.5° / mm. Meeting the above conditions can ensure that the optical lens has a large field angle characteristic on the premise of meeting the image height requirement, so that the optical lens has good optical performance and can capture the details of the photographed object well.

[0078] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.3 < IH / EPD < 2.9. Meeting the above range enables the optical lens to meet the large image plane while ensuring sufficient image plane brightness in the marginal field of view, preventing the occurrence of vignetting phenomenon, and thus improving the imaging quality.

[0079] In some embodiments, the sixth lens may have a convex-convex surface type, and the object-side curvature radius R11 and the image-side curvature radius R12 of the sixth lens satisfy: -0.45 < (R11 + R12) / (R11 - R12) < -0.15. Reasonably controlling the curvature radius and surface type of the object side and the image side of the sixth lens can effectively control the shape of the sixth lens, and then control the refraction angle of the light rays, which is beneficial to quickly converging the divergent light rays emitted by the fifth lens, shortening the total length of the optical system. At the same time, it can reduce the height of the light rays entering the seventh lens, which is beneficial to reducing the aperture of the seventh lens, thereby reducing the production and manufacturing cost of the lens.

[0080] In some embodiments, the object-side curvature radius R11 of the sixth lens and the focal length f6 of the sixth lens satisfy: 0.6 < R11 / f6 < 0.88; the image-side curvature radius R12 of the sixth lens and the focal length f6 of the sixth lens satisfy: -1.7 < R12 / f6 < -1. By making the optical system satisfy the above relational expressions, the bending degrees of the object side and the image side of the sixth lens can be controlled, making the surface type of the sixth lens more reasonable and having better forming and processing characteristics.

[0081] In some embodiments, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: -6 < f2 / f3 < -3.5. Reasonably controlling the ratio range of the focal lengths of the second lens and the third lens is beneficial for the light to smoothly transition to the third lens, which is conducive to reducing distortion and improving the relative illumination at the edge.

[0082] In some embodiments, the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: -0.7 < f6 / f7 < -0.44. Constraining the ratio of the focal lengths of the two lenses of the sixth lens and the seventh lens within a certain range, the change amount of the optical path passing through the two lenses at high and low temperatures is small, making the thermal contribution amounts of the lenses at high and low temperatures close, which is beneficial for the entire optical system to maintain stable performance within a large temperature change range.

[0083] In some embodiments, the central thickness CT2 of the second lens and the central thickness CT3 of the third lens satisfy: 1.4 < CT2 / CT3 < 1.8. Reasonably configuring the ratio of the thickness of the second lens on the optical axis to the thickness of the third lens on the optical axis enables the second lens and the third lens to mutually regulate and maintain the characteristic of the miniaturization of the optical system.

[0084] In some embodiments, the spacing CT34 between the third lens and the fourth lens on the optical axis, the spacing CT56 between the fifth lens and the sixth lens on the optical axis, and the total optical length TTL of the optical lens satisfy: 0.08 < (CT34 + CT56) / TTL < 0.18. Meeting the above conditional formula, by reasonably controlling the air gap between the third lens and the fourth lens and the air gap between the fifth lens and the sixth lens, the total optical length can be shortened and the characteristic of the miniaturization of the optical system can be maintained.

[0085] In some embodiments, the sagittal height SAG32 of the image-side clear aperture of the third lens and the central thickness CT3 of the third lens satisfy: -0.15 < SAG32 / CT3 < -0.05. This helps to reasonably control the shape of the third lens, making the image side of the third lens flatter. On the one hand, it is beneficial to coat an IR film on the image side of the third lens, avoiding difficult coating, ensuring the filtering performance of the IR film, and at the same time, coating the IR film on the third lens is beneficial for reducing ghost images of the lens and improving imaging clarity. On the other hand, it is beneficial to control the light path, making the aberration of the system smaller and improving the imaging quality of the system.

[0086] In some embodiments, the clear aperture semi-diameter DM11 of the object side of the first lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.6 < DM11 / IH < 0.8. Meeting the above range can ensure the balance between the front aperture diameter of the optical lens and the image plane size.

[0087] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half-field angle of the optical lens satisfy: 1 < (IH / 2) / (f×θ) < 1.02. Meeting the above conditions can better achieve small distortion and is more conducive to achieving high resolution.

[0088] In some embodiments, the distance BL from the image side of the seventh lens to the imaging surface on the optical axis and the total optical length TTL of the optical lens satisfy: 0.08 < BL / TTL < 0.12. This is conducive to achieving a short back focal length of the optical lens and, while ensuring sufficient space for the installation and focusing of optical elements, is conducive to the miniaturization of the optical lens.

[0089] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.4 < TTL / f < 6.7. Meeting the above range can effectively limit the length of the lens and is conducive to the miniaturization of the optical lens.

[0090] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 50° < f×FOV / IH < 62°. Meeting the above conditional formula can, by reasonably restricting the relationship between the focal length, field angle, and image height of the optical lens, achieve long focal length and large field imaging while meeting a certain image height, thereby improving the imaging quality.

[0091] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.4 < IH / f < 1.8. Meeting the above conditions can achieve a larger field angle and imaging range, and can achieve the characteristics of a large image plane while ensuring the depth of field of the optical lens, thereby improving the imaging quality of the optical system.

[0092] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 3.3 < TTL / IH < 4.1. This can better achieve the miniaturization of the lens, and at the same time, ensure that the lens has a larger image plane under the same total length, and can match a larger-sized imaging chip to achieve high-definition imaging.

[0093] In some embodiments, the first lens may have a convex-concave surface shape. The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -0.61 < f / f1 < -0.48; the object-side curvature radius R1 of the first lens and the focal length f1 of the first lens satisfy: -2.4 < R1 / f1 < -1.8; the image-side curvature radius R2 of the first lens and the focal length f1 of the first lens satisfy: -0.6 < R2 / f1 < -0.47. The first lens has a negative optical power. When the field angle is fixed, the subsequent optical system can have a larger light-receiving surface, which is beneficial to improving the illumination of marginal rays. The object side of the first lens is convex, which is convenient for collecting light rays in a large field of view as much as possible, thereby improving the light flux and illumination of the lens. At the same time, it is also beneficial to the sliding of water droplets, avoiding the problem of dust accumulation, and ensuring the imaging clarity of the lens. The image side of the first lens is concave, which can quickly diverge light rays, facilitating the realization of a large field of view. Thus, the incident angle of light when entering the first lens can be controlled, ensuring that the light rays can be effectively received and processed by the subsequent lens group, and further improving the light flux and imaging efficiency of the entire optical imaging lens.

[0094] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.33 < f / f3 < 0.45. The third lens converges the incident light rays at the front end, which is beneficial to correcting the aberration and distortion of the marginal field brought by the front negative lens group, enabling the lens to have less distortion and providing a high-definition imaging effect.

[0095] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.48 < f / f4 < 0.7; the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -0.7 < f / f5 < -0.45. The focal lengths f4 of the fourth lens and f5 of the fifth lens satisfy: -1.1 < f4 / f5 < -0.85. The fourth lens and the fifth lens are glued together to form a doublet lens. The fourth lens and the fifth lens can have optical powers with opposite signs, which is beneficial to correcting chromatic aberration, improving the resolution, and achieving high resolution. At the same time, the use of the glued part is beneficial to reducing the tolerance sensitivity of the lens to tilt / eccentricity, etc. during the assembly process, improving the resolution stability, and further enhancing the system performance. By reasonably distributing the focal lengths of the fourth lens and the fifth lens, it helps to achieve thermal compensation, enabling the optical lens to have good temperature performance.

[0096] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.4 < f / f6 < 0.55. The sixth lens satisfying the above conditions can focus the divergent light rays emerging from the doublet lens, which is beneficial to reducing the aperture of the seventh lens. At the same time, it can correct distortion and improve the imaging quality of the lens.

[0097] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -0.35 < f / f7 < -0.2. The seventh lens has an appropriate negative focal length, which is beneficial to further increasing the imaging area of the optical lens, and at the same time is beneficial to reducing the CRA, and can better match the chip. More specifically, the seventh lens can be an aspherical lens. The object side surface of the seventh lens can have an anticlastic curvature, with a convex surface near the optical axis and a concave surface at the edge, which is beneficial to balancing various aberrations generated by the front group of lenses and improving the imaging quality of the optical lens.

[0098] In some embodiments, the effective focal length f of the optical lens and the focal length f45 of the seventh lens satisfy: 0.01 < f / f45 < 0.1. Meeting the above range, by reasonably limiting the light power ratio of the cemented lens composed of the fourth lens and the fifth lens, it is beneficial to reduce chromatic aberration and spherical aberration and improve the imaging quality.

[0099] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 50° < FOV / Fno < 62°. Meeting the above range, by reasonably limiting the ratio of the maximum field of view to the aperture value, it is possible to collect light at large angles and obtain good imaging quality.

[0100] In some embodiments, the true image height IH corresponding to the maximum field of view of the optical lens and the aperture value Fno of the optical lens satisfy: 5mm < IH / Fno < 6.5mm. Meeting the above conditions, while maintaining a large image plane for the optical lens, ensuring that the optical lens has a large aperture, and achieving the balance of a large image plane and a large aperture.

[0101] In some embodiments, the curvature radius R7 of the object side surface of the fourth lens and the curvature radius R8 of the image side surface of the fourth lens satisfy: -1.1 < R7 / R8 < -0.55; 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: -0.7 < R9 / R10 < -0.4. By controlling the ratio of the curvature radii of the object side surface and the image side surface of the fourth lens and the object side surface and the image side surface of the fifth lens in the cemented lens, the angular difference of the light entering and exiting the cemented lens can be effectively adjusted, which is beneficial to achieving small distortion.

[0102] In some embodiments, the curvature radius R13 of the object side surface of the seventh lens and the curvature radius R14 of the image side surface of the seventh lens satisfy: 1.5 < (R13 + R14) / (R13 - R14) < 3.2. Meeting the above range, by reasonably limiting the shape of the object side surface and the image side surface of the seventh lens, it is possible to control the seventh lens to have an appropriate surface shape, which helps to control the light trend of the edge field of view and improve the imaging quality of the edge field of view.

[0103] In some embodiments, the radius of curvature R13 of the object side surface of the seventh lens and the focal length f7 of the seventh lens satisfy: -2.6 < R13 / f7 < -0.7; the radius of curvature R14 of the image side surface of the seventh lens and the focal length f7 of the seventh lens satisfy: -0.5 < R14 / f7 < -0.35. Satisfying the above ranges, by reasonably defining the light power ratio and the surface shape of the seventh lens, it is beneficial to increase the divergence degree of light rays, increase the area of light rays entering the imaging surface, achieve large target surface imaging, and at the same time is beneficial to balancing aberrations such as distortion and improving the imaging quality of the lens. The image side surface of the seventh lens is a concave surface, which can further diverge the light rays, reduce the incident angle of the chief ray entering the chip, and help improve the illuminance of the lens.

[0104] 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 seventh lens along the optical axis satisfy: 0.5 < ∑CT / TTL < 0.68. Satisfying the above range can effectively compress the overall length of the optical lens.

[0105] In some embodiments, the radius of curvature R1 of the object side surface of the first lens, the radius of curvature R2 of the image side surface of the first lens and the central thickness CT1 of the first lens satisfy: 2.8 < R1 / (R2 + CT1) < 3.6. Satisfying the above range can reduce the correction difficulty of the marginal field distortion and control the distortion within a reasonable range.

[0106] In some embodiments, the sagittal height SAG71 of the object side surface clear aperture of the seventh lens, the sagittal height SAG72 of the image side surface clear aperture of the seventh lens and the central thickness CT7 of the seventh lens satisfy: 0.27 < (SAG72 - SAG71) / CT7 < 0.5. By controlling the relationship between the height difference of the sagittal heights of the image side surface and the object side surface of the seventh lens and the central thickness of the seventh lens, it is beneficial to correct the coma of the off-axis field and improve the imaging quality of the off-axis field of the optical lens.

[0107] In some embodiments, the clear aperture semi-diameter DM11 of the object side surface of the first lens and the clear aperture semi-diameter DM72 of the image side surface of the seventh lens satisfy: 1.3 < DM11 / DM72 < 1.7. Satisfying the above conditions can effectively reduce the aperture size of the lens while ensuring that light rays enter the system within a large range, which is beneficial to achieving the balance of the field of view and the aperture of the lens.

[0108] In some embodiments, the optical lens satisfies the following conditional expressions: 5mm < f < 6.5mm; 1.5 < Fno < 1.8; 82° < FOV < 100°; 8.5mm < IH < 10.5mm. In the above conditional expressions, f represents the effective focal length of the optical lens, Fno represents the aperture value of the optical lens, FOV represents the maximum field angle of the optical lens, and IH represents the true image height corresponding to the maximum field angle of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as a large image plane, a large aperture, and a large field angle.

[0109] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, due to the low dispersion characteristics of glass itself, the geometric chromatic aberration of the optical system can be effectively corrected. The optical lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0110] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the seventh lens of the present invention adopts an aspherical lens; the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens adopt spherical lenses.

[0111] In various embodiments of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the zoom lens satisfy the following equations:

[0112] ;

[0113] where z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the quadratic surface coefficient, and B, C, D, E, F, G, H are the surface coefficients of the fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order respectively.

[0114] The present invention will be further described in multiple embodiments below. In each embodiment, the thickness, curvature radius, and material selection of each lens in the optical lens are somewhat different. For specific differences, refer to the parameter tables of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any other changes, substitutions, combinations, or simplifications made without departing 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.

[0115] Example 1

[0116] Please see Figure 1 The diagram shows a schematic of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 includes, along the optical axis from the object side to the imaging surface, the following components in sequence: 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 seventh lens L7, and a protective glass G1.

[0117] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0118] The second lens L2 has negative optical power, its object side S3 is concave, and its image side S4 is convex.

[0119] The third lens L3 has positive optical power, its object side S5 is convex, and its image side S6 is convex.

[0120] The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side is convex.

[0121] The fifth lens L5 has negative optical power, its object side is concave, and its image side S9 is concave.

[0122] The fourth lens L4 and the fifth lens L5 form a cemented lens group with positive optical power, that is, the cemented surface of the image side of the fourth lens L4 and the object side of the fifth lens L5 is S8.

[0123] The sixth lens L6 has positive optical power, its object side S10 is convex, and its image side S11 is convex.

[0124] The seventh lens L7 has negative optical power, its object side S12 is convex near the optical axis, and its image side S13 is concave.

[0125] The object side S14 and image side S15 of the protective glass G1 are both flat.

[0126] The imaging plane S16 is a plane.

[0127] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are glass spherical lenses; the seventh lens L7 is a glass aspherical lens.

[0128] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0129] Table 1-1

[0130]

[0131] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0132] Table 1-2

[0133]

[0134] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown.

[0135] Figure 2 The field curvature curve of Example 1 is shown, which represents the degree of curvature of light in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within -0.04 mm to 0.02 mm, indicating that the optical lens can effectively correct the field curvature.

[0136] Figure 3 The F-Theta distortion curve of Example 1 is shown, which represents the F-Theta distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within 0~2%, indicating that the optical lens can correct distortion well.

[0137] 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. As can be seen from the figure, the axial aberration offset is controlled within -0.02 mm to 0.01 mm, indicating that the optical lens can correct axial aberration well.

[0138] Figure 5 The diagram shows the transverse chromatic aberration curves for Example 1, representing the chromatic aberration of each wavelength relative to the center wavelength (0.546 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2 μm to 1 μm, indicating that the optical lens can effectively correct chromatic aberration.

[0139] Figure 6The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the lens imaging modulation at different spatial frequencies in various fields of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents MTF value. As can be seen from the figure, the MTF value of this example is above 0.35 throughout the entire field of view. Within the range of 0–120 lp / mm, the MTF curve decreases smoothly and uniformly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0140] Figure 7 The relative illumination curves for Example 1 are shown, representing the relative illumination values ​​at different field-of-view angles on the imaging plane. The horizontal axis represents the field-of-view angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 75% at the maximum half-field-of-view angle, indicating that the optical lens has good relative illumination.

[0141] Example 2

[0142] Please see Figure 8 The figure shown is a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0143] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0144] Table 2-1

[0145]

[0146] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0147] Table 2-2

[0148]

[0149] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination curve of the optical lens 200 are respectively as follows: Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13 , Figure 14 As shown.

[0150] from Figure 9 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.04mm to 0.02mm, indicating that the optical lens can effectively correct the field curvature.

[0151] from Figure 10 As can be seen, the F-Theta distortion of the optical lens is controlled within 0~2%, indicating that the optical lens can correct distortion well.

[0152] from Figure 11 As can be seen, the axial aberration offset is controlled within -0.02mm to 0.01mm, indicating that the optical lens can effectively correct axial aberration.

[0153] from Figure 12 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2μm to 1μm, indicating that the optical lens can correct chromatic aberration well.

[0154] from Figure 13 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0155] from Figure 14 As can be seen, the relative illumination value of the optical lens is still greater than 75% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0156] Example 3

[0157] Please see Figure 15 The figure shown is a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0158] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0159] Table 3-1

[0160]

[0161] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0162] Table 3-2

[0163]

[0164] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination curve of the optical lens 300 are respectively as follows: Figure 16 , Figure 17 , Figure 18 , Figure 19 , Figure 20 , Figure 21 As shown.

[0165] from Figure 16 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.04mm to 0.02mm, indicating that the optical lens can effectively correct the field curvature.

[0166] from Figure 17 As can be seen, the F-Theta distortion of the optical lens is controlled within 0~2%, indicating that the optical lens can correct distortion well.

[0167] from Figure 18 As can be seen, the axial aberration offset is controlled within -0.02mm to 0.01mm, indicating that the optical lens can effectively correct axial aberration.

[0168] from Figure 19 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2μm to 1μm, indicating that the optical lens can correct chromatic aberration well.

[0169] from Figure 20 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0170] from Figure 21 As can be seen, the relative illumination value of the optical lens is still greater than 75% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0171] Example 4

[0172] Please see Figure 22 The figure shown is a schematic diagram of the structure of the optical lens 400 provided in Embodiment 4 of the present invention. The main difference between this embodiment and Embodiment 1 is that the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0173] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0174] Table 4-1

[0175]

[0176] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0177] Table 4-2

[0178]

[0179] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination curve of the optical lens 400 are respectively as follows: Figure 23 , Figure 24 , Figure 25 , Figure 26 , Figure 27 , Figure 28 As shown.

[0180] from Figure 23 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.04mm to 0.02mm, indicating that the optical lens can effectively correct the field curvature.

[0181] from Figure 24 As can be seen, the F-Theta distortion of the optical lens is controlled within 0~2%, indicating that the optical lens can correct distortion well.

[0182] from Figure 25 As can be seen, the axial aberration offset is controlled within -0.02mm to 0.01mm, indicating that the optical lens can effectively correct axial aberration.

[0183] from Figure 26 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1μm, indicating that the optical lens can effectively correct chromatic aberration.

[0184] from Figure 27 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0185] from Figure 28 As can be seen, the relative illumination value of the optical lens is still greater than 80% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0186] Example 5

[0187] Please see Figure 29 The figure shown is a schematic diagram of the structure of the optical lens 500 provided in Embodiment 5 of the present invention. The main difference between this embodiment and Embodiment 1 is that the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0188] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0189] Table 5-1

[0190]

[0191] The surface profile parameters of the aspherical lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0192] Table 5-2

[0193]

[0194] In this embodiment, the field curvature curve, F-Theta distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination curve of the optical lens 500 are respectively as follows: Figure 30 , Figure 31 , Figure 32 , Figure 33 , Figure 34 , Figure 35 As shown.

[0195] from Figure 30 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within -0.04mm to 0.02mm, indicating that the optical lens can effectively correct the field curvature.

[0196] from Figure 31 As can be seen, the F-Theta distortion of the optical lens is controlled within 0~2%, indicating that the optical lens can correct distortion well.

[0197] from Figure 32 As can be seen, the axial aberration offset is controlled within -0.02mm to 0.01mm, indicating that the optical lens can effectively correct axial aberration.

[0198] from Figure 33 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -2μm to 1μm, indicating that the optical lens can correct chromatic aberration well.

[0199] from Figure 34 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0200] from Figure 35 As can be seen, the relative illumination value of the optical lens is still greater than 70% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0201] Please refer to Tables 6-1 and 6-2 for the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, true image height IH corresponding to the maximum field of view, maximum field of view FOV, distance BL from the image side of the seventh lens to the imaging plane on the optical axis, and the numerical values ​​corresponding to each conditional expression in each embodiment.

[0202] Table 6-1

[0203]

[0204] Table 6-2

[0205]

[0206] In summary, the optical lens provided by the present invention employs seven lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as a large image plane, a large aperture, and high imaging quality.

[0207] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0208] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens comprising seven lenses having optical power, characterized in that, It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is convex and whose image side is concave; A second lens with a negative optical power, whose object side is concave and whose image side is convex; A third lens with a positive optical power, whose object side is convex and whose image side is convex; A fourth lens with a positive optical power, whose object side is convex and whose image side is convex; A fifth lens with a negative optical power, whose object side is concave and whose image side is concave; A sixth lens with a positive optical power, whose object side is convex and whose image side is convex; A seventh lens with a negative optical power, whose object side is convex near the optical axis and whose image side is concave; Among them, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -0.15 < f / f2 < -0.05; The radius of curvature R3 of the object side of the second lens and the effective focal length f of the optical lens satisfy: -1.7 < R3 / f < -1.2; The radius of curvature R4 of the image side of the second lens and the effective focal length f of the optical lens satisfy: -2.8 < R4 / f < -1.8; The maximum field angle FOV of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 9° / mm < FOV / IH < 10.5° / mm.

2. The optical lens according to claim 1, characterized in that, The combined focal length f13 of the first lens, the second lens and the third lens and the combined focal length f47 of the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy: 0.85 < f13 / f47 < 1.

2.

3. The optical lens according to claim 1, characterized in that, 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: -0.7 < R9 / R10 < -0.

4.

4. The optical lens according to claim 1, characterized in that, The true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 2.3 < IH / EPD < 2.

9.

5. The optical lens according to claim 1, characterized in that, The radius of curvature R11 of the object side of the sixth lens and the radius of curvature R12 of the image side of the sixth lens satisfy: -0.45 < (R11 + R12) / (R11 - R12) < -0.15; the radius of curvature R11 of the object side of the sixth lens and the focal length f6 of the sixth lens satisfy: 0.6 < R11 / f6 < 0.88; the radius of curvature R12 of the image side of the sixth lens and the focal length f6 of the sixth lens satisfy: -1.7 < R12 / f6 < -1.

6. The optical lens according to claim 1, characterized in that, The focal length f2 of the second lens and the focal length f3 of the third lens satisfy: -6 < f2 / f3 < -3.5; the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: -0.7 < f6 / f7 < -0.

44.

7. The optical lens according to claim 1, characterized in that, The central thickness CT2 of the second lens and the central thickness CT3 of the third lens satisfy: 1.4 < CT2 / CT3 < 1.

8.

8. The optical lens according to claim 1, characterized in that, The distance CT34 between the third lens and the fourth lens on the optical axis, the distance CT56 between the fifth lens and the sixth lens on the optical axis, and the total optical length TTL of the optical lens satisfy the following condition: 0.08 < (CT34 + CT56) / TTL < 0.

18.

9. The optical lens according to claim 1, characterized in that, The image-side half-aperture sagitta SAG32 of the third lens and the center thickness CT3 of the third lens satisfy the condition: -0.15 <SAG32 / CT3<-0.05。 10. The optical lens according to claim 1, characterized in that, The half-aperture DM11 of the object-side surface of the first lens and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 0.6 <DM11 / IH<0.8。

Images