Optical lens

Abstract

The invention provides an optical lens, which comprises seven lenses with focal power and sequentially comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power from an object side to an imaging surface along an optical axis, the object side surface of the second lens is a concave surface, and the image side surface of the second lens near the optical axis is a convex surface; the third lens has negative focal power; the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface; the fifth lens has positive focal power, and the image side surface of the fifth lens is a convex surface; the sixth lens has negative focal power, and the image side surface of the sixth lens is a concave surface; and the object side surface of the seventh lens is a convex surface near the optical axis, and the image side surface of the seventh lens is a concave surface near the optical axis. According to the optical lens provided by the invention, the imaging quality of the optical lens can be improved, and the optical lens has the advantage of excellent imaging quality.

Description

Technical Field

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

[0002] With the popularization of remote work and online education, video conferencing has become an indispensable part of people's daily life and work. The quality of video conferencing largely depends on the optical lens of the video conferencing, which puts higher requirements on the video conferencing lens. For example, in order to provide clear video quality, video conferencing lenses usually need to provide high resolution, such as 1080p or 4K; for another example, in order to effectively capture the participants in the meeting room, it is often required that the video conferencing lens can have a larger shooting range. Traditional video conferencing lenses more or less have some limitations, such as low resolution, small shooting range, and poor imaging effect in low light or dim environments. Therefore, there is an urgent need to provide an optical lens that can meet the usage requirements of video conferencing. Summary of the Invention

[0003] Aiming at the above problems, the purpose of the present invention is to provide an optical lens, which has the advantage of excellent imaging quality.

[0004] The present invention provides an optical lens, which has seven lenses with optical power, and successively includes along the optical axis from the object side to the imaging surface:

[0005] A first lens with negative optical power, whose object side is convex and whose image side is concave;

[0006] A second lens with negative optical power, whose object side is concave and whose image side is convex near the optical axis;

[0007] A third lens with negative optical power;

[0008] A fourth lens with positive optical power, whose object side is convex and whose image side is convex;

[0009] A fifth lens with positive optical power, whose image side is convex;

[0010] A sixth lens with negative optical power, whose image side is concave;

[0011] A seventh lens with negative optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis;

[0012] Wherein, the curvature radius R3 of the object side of the second lens and the focal length f2 of the second lens satisfy: 0.18 < R / f < 0.48; the curvature radius R4 of the image side of the second lens and the focal length f2 of the second lens satisfy: 0.3 < R / f < 3.

[0013] Further preferably, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 0.4 < f4 / f5 < 1.4.

[0014] Further preferably, the object-side curvature radius R11 of the sixth lens and the focal length f6 of the sixth lens satisfy: -0.4 < R11 / f6 < 0.8; the image-side curvature radius R12 of the sixth lens and the focal length f6 of the sixth lens satisfy: -11 < R12 / f6 < -0.2.

[0015] Further preferably, 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: 38° < f × FOV / IH < 55°.

[0016] 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: 8.7° / mm < FOV / IH < 13° / mm.

[0017] Further preferably, the object-side curvature radius R11 of the sixth lens and the image-side curvature radius R12 of the sixth lens satisfy: -0.1 < R11 / R12 < 1.8.

[0018] Further preferably, the object-side curvature radius R1 of the first lens, the image-side curvature radius R2 of the first lens, and the central thickness CT1 of the first lens satisfy: 1.9 < R1 / (R2 + CT1) < 2.8.

[0019] Further preferably, the distance CT67 between the sixth lens and the seventh lens on the optical axis and the image-side curvature radius R12 of the sixth lens satisfy: 0.01 < CT67 / R12 < 0.9.

[0020] Further preferably, the object-side clear aperture semi-diameter DM11 of the first lens and the focal length f1 of the first lens satisfy: 0.19 < DM11 / f1 < 0.9.

[0021] Further preferably, the object-side clear aperture sag SAG71 of the seventh lens, the image-side clear aperture sag SAG72 of the seventh lens, and the central thickness CT7 of the seventh lens satisfy: -0.53 < (SAG72 - SAG71) / CT7 < -0.28.

[0022] Compared with existing technologies, 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 small focal length, large field of view, small distortion, good thermal stability, and high resolution. Attached Figure Description

[0023] 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:

[0024] Figure 1 This is a schematic diagram of the optical lens structure in Embodiment 1 of the present invention.

[0025] Figure 2 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0026] Figure 3 This is an axial aberration curve of the optical lens in Embodiment 1 of the present invention.

[0027] Figure 4 This is a relative illumination curve of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 5 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 6 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0030] Figure 7 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 8 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 9 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 10 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 11 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0035] Figure 12 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0036] Figure 13 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0037] Figure 14 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0038] Figure 15 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0039] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The optical lens provided in this embodiment of the invention has seven lenses with optical power, which are arranged sequentially along the optical axis from the object side to the imaging plane as follows: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens.

[0048] In some embodiments, the first lens may have negative optical power, with a convex object-side surface and a concave image-side surface. The second lens may have negative optical power, with a concave object-side surface and a convex image-side surface near the optical axis. The third lens may have negative optical power, with both a concave and convex object-side surface and an image-side surface. The fourth lens may have positive optical power, with both a convex object-side surface and an image-side surface. The fifth lens may have positive optical power, with both a concave and convex object-side surface and an image-side surface. The sixth lens may have negative optical power, with both a concave and convex object-side surface and an image-side surface. The seventh lens may have negative optical power, with a convex object-side surface near the optical axis and a concave image-side surface near the optical axis.

[0049] In some embodiments, the optical lens may also include an aperture stop, which may be located between the fourth and fifth lenses. It is understood that the aperture stop is used to limit the amount of light entering the lens, thereby altering the brightness of the image.

[0050] In some embodiments, the optical lens may further include a filter and a protective glass, which are sequentially arranged between the seventh lens and the imaging surface along the optical axis. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass serves to protect the optical lens and prevent the photosensitive chip from being damaged.

[0051] In some embodiments, the radius of curvature R3 of the object side surface of the second lens and the focal length f2 of the second lens satisfy: 0.18 < R3 / f2 < 0.48; the radius of curvature R4 of the image side surface of the second lens and the focal length f2 of the second lens satisfy: 0.3 < R4 / f2 < 3. Meeting the above conditions is beneficial to controlling the surface shape and effective focal length of the second lens and is beneficial to balancing the axial chromatic aberration.

[0052] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 0.4 < f4 / f5 < 1.4. Meeting the above range is beneficial to the smooth transition of light rays, beneficial to correcting the aberration of the optical lens, and improving the imaging quality of the optical lens.

[0053] In some embodiments, the radius of curvature R11 of the object side surface of the sixth lens and the focal length f6 of the sixth lens satisfy: -0.4 < R11 / f6 < 0.8; the radius of curvature R12 of the image side surface of the sixth lens and the focal length f6 of the sixth lens satisfy: -11 < R12 / f6 < -0.2. By making the optical system satisfy the above relational expressions, the bending degrees of the object side surface and the image side surface of the sixth lens can be controlled, making the surface shape of the sixth lens more reasonable and having better molding and processing characteristics.

[0054] 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: 38° < f×FOV / IH < 55°. Meeting the above conditional expression, by reasonably restricting the relationship between the focal length, field angle, and image height of the optical lens, it is beneficial to achieving the balance of the large field angle and large target surface imaging of the optical lens, and better meeting the use requirements of high image quality and wide-angle shooting in a video conference room environment.

[0055] 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: 8.7° / mm < FOV / IH < 13° / 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 well capture the details of the photographed object.

[0056] In some embodiments, 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: -0.1 < R11 / R12 < 1.8. Meeting the above conditions enables smooth transition of light rays, helps balance various aberrations, and reduces the lens sensitivity to a certain extent.

[0057] 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: 1.9 < R1 / (R2 + CT1) < 2.8. Meeting the above range can reduce the difficulty of correcting the edge field distortion and control the distortion within a reasonable range.

[0058] In some embodiments, the distance CT67 between the sixth lens and the seventh lens on the optical axis and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0.01 < CT67 / R12 < 0.9. Meeting the above conditions allows for a large air gap between the sixth lens and the seventh lens, ensuring a high receiving efficiency and imaging quality of the imaging surface while restricting the volume of the optical lens, and ultimately achieving a wide-angle field of view of the optical lens.

[0059] In some embodiments, the clear aperture semi-diameter DM11 of the object side surface of the first lens and the focal length f1 of the first lens satisfy: 0.19 < DM11 / f1 < 0.9. By controlling the ratio of the clear aperture semi-diameter of the object side surface of the first lens to the focal length of the first lens, the lens shape of the first lens can be reasonably controlled, enabling light rays to enter the object side surface of the first lens at the maximum incident angle and achieving wide-angleization of the optical system.

[0060] In some embodiments, the sag SAG71 of the clear aperture of the object side surface of the seventh lens, the sag SAG72 of the clear aperture of the image side surface of the seventh lens, and the central thickness CT7 of the seventh lens satisfy: -0.53 < (SAG72 - SAG71) / CT7 < -0.28. By controlling the difference between the convexities of the two mirror surfaces of the seventh lens and the central thickness, it is beneficial to the mechanical shaping of the seventh lens, reduces the sensitivity of the optical imaging lens, and better balances the relationship between the miniaturization of the optical imaging lens and the off-axis relative illumination.

[0061] In some embodiments, the distance BL from the image side surface 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 < 0.15. This is beneficial for achieving a short back focal length of the optical lens and is conducive to the miniaturization of the optical lens while ensuring sufficient space for the installation of optical components.

[0062] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 3.2 < TTL / f < 9. This can effectively limit the length of the lens and is conducive to the miniaturization of the optical lens.

[0063] 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: 2.2 < IH / f < 3.3. 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.

[0064] In some embodiments, the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.3 < TTL / IH < 3.2. It 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 overall length, and can match a larger-sized imaging chip to achieve high-definition imaging.

[0065] 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 < -1.4. The first lens is designed as a negative lens, which can effectively increase the back focal length of the optical system, making it have a longer mechanical back focus, which is beneficial to replacing the lens mount material to adjust the back focus at high and low temperatures, and further matching the requirements of the module.

[0066] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -18 < f2 / f < -3.9. When the second lens meets the above conditions, it can control the light path direction, provide a more reasonable light incident angle for the subsequent lenses, and reduce astigmatism and field curvature.

[0067] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -55 < f3 / f < -27. The third lens also uses a negative lens, which can further diverge light and increase the field angle of the imaging system.

[0068] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.8 < f4 / f < 2. The fourth lens converges the incident light at the front end, which is beneficial to correcting the aberration and distortion of the edge field caused by the first lens, making the lens have less distortion and providing a high-definition imaging effect.

[0069] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 1.2 < f5 / f < 2.2. By reasonably setting the focal length ratio of the fifth lens, it is beneficial to the smooth transition of light, facilitating the correction of astigmatism and field curvature, improving the imaging quality of the optical lens, and ensuring the stability of the optical system.

[0070] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -3.3 < f6 / f < -1.2. By setting the sixth lens to have a negative optical power, the beam diameter can be reduced, and the size of the subsequent lens group can be reduced.

[0071] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -82 < f7 / f < -45. The seventh lens has an appropriate negative focal length, which is beneficial to further increase the imaging area of the optical lens, balance various aberrations generated by the front lens group at the same time, and improve the imaging quality of the optical lens.

[0072] In some embodiments, the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 37° < FOV / Fno < 72°. Meeting the above range and reasonably limiting the ratio of the maximum field angle to the aperture value can collect light at large angles and obtain good imaging quality.

[0073] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 4mm < IH / Fno < 6.2mm. Meeting the above conditions can ensure a large aperture of the optical lens while maintaining a large image plane of the optical lens, achieving the balance of a large image plane and a large aperture.

[0074] 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: 5.3 < IH / EPD < 7. Meeting the above range enables the optical lens to satisfy a large image plane and sufficient image plane brightness in the edge field of view at the same time to prevent vignetting, thereby improving the imaging quality.

[0075] In some embodiments, the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: 3 < R1 / R2 < 6. The surface shape of the first lens can be reasonably set to enhance the light collection ability of the first lens, thereby achieving a larger field angle.

[0076] In some embodiments, the curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: -5 < (R3 + R4) / (R3 - R4) < -1.2. By making the optical system satisfy the above relational expression, it is beneficial to reasonably configure the ratio of the curvature radius of the object side surface of the second lens to the curvature radius of the image side surface of the second lens, control the shape of the second lens, comprehensively balance the spherical aberration, chromatic aberration and field curvature of the optical system, reduce the risk of ghost imaging, improve the resolution ability of the optical system, and at the same time, it is also beneficial to reduce the processing difficulty of the fourth lens.

[0077] In some embodiments, 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: -9.5 < (R11 + R12) / (R11 - R12) < 4.6. By reasonably controlling the radius of curvature of the object side surface and the radius of curvature of the image side surface of the sixth lens, the shape of the sixth lens can be effectively controlled, and then the refraction angle of light can be controlled, so that the exit angle of the light after passing through the optical imaging system better matches the chip.

[0078] In some embodiments, the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: 15 < (R13 + R14) / (R13 - R14) < 22. Satisfying the above range and reasonably defining the shapes of the object side surface and the image side surface of the seventh lens can 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.

[0079] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.14 < f1 / f2 < 0.4. By reasonably setting the focal length ratio of the first lens and the second lens, the system length can be shortened, the aberration and the distortion of the edge field of view can be reduced, so that the lens has less distortion and can provide a high-definition imaging effect.

[0080] In some embodiments, the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: 0.01 < f6 / f7 < 0.05. Satisfying the above range and reasonably setting the focal length relationship between the sixth lens and the seventh lens can converge the incident angle of the edge light, improve the illumination uniformity and clarity of the picture edge, and at the same time finely correct aberrations such as distortion, so that the video conference picture can obtain a high-quality, dark-corner-free and non-deformed clear image.

[0081] In some embodiments, the central thickness CT3 of the third lens and the central thickness CT4 of the fourth lens satisfy: 0.55 < CT3 / CT4 < 10. Satisfying the above conditions can effectively eliminate the field curvature and ensure that the lens assembly has better processability.

[0082] In some embodiments, the central thickness CT5 of the fifth lens and the central thickness CT6 of the sixth lens satisfy: 1.7 < CT5 / CT, < 6.5. Satisfying the above conditions can reduce the sensitivity of the system performance, while ensuring the lens processability and assembly stability, and improving the assembly yield.

[0083] In some embodiments, the total 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 respectively satisfy: 0.4 < ∑CT / TTL < 0.6. Satisfying the above conditions can effectively compress the total length of the optical lens, and at the same time is beneficial to the structural design and production process of the optical lens.

[0084] In some embodiments, the clear aperture semi-diameter DM11 of the object side of the first lens and the clear aperture semi-diameter DM72 of the image side of the seventh lens satisfy: 0.9 < DM11 / DM72 < 3.9. By reasonably setting the ratio of the apertures of the first and last lenses, the lens can have a smaller head size while having a larger imaging surface, better meeting the balance of miniaturization and high pixels.

[0085] 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: 0.05 < DM11 / IH < 0.32. Meeting the above conditions can ensure that the lens has a large field angle while ensuring that the overall size of the lens is appropriate.

[0086] In some embodiments, the sagittal height SAG21 of the clear aperture of the object side of the second lens, the sagittal height SAG22 of the clear aperture of the image side of the second lens, and the central thickness CT2 of the second lens satisfy: 0.19 < (SAG22 - SAG21) / CT2 < 0.72. Meeting the above conditions can limit the degree of central depression of the second lens and reduce the difficulty of aberration correction in the marginal field of view.

[0087] In some embodiments, the sagittal height SAG61 of the clear aperture of the object side of the sixth lens, the sagittal height SAG62 of the clear aperture of the image side of the sixth lens, and the central thickness CT6 of the sixth lens satisfy: 0.67 < (SAG62 - SAG61) / CT6 < 2.5. This helps to reasonably control the shape of the third lens. On the one hand, it is beneficial to control the light path, making the aberration of the system smaller and improving the imaging quality of the system. On the other hand, it is beneficial to the lens forming process and avoids difficulties in the processing technology.

[0088] In some embodiments, the optical lens satisfies the conditional formula: 3.8 mm < f < 5 mm, 16 mm < TTL < 35 mm, 2 < Fno < 2.8, 10 mm < IH < 14 mm, 100° < FOV < 160°, where f represents the effective focal length of the optical lens, TTL represents the overall optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field angle of the optical lens, and FOV represents the maximum field angle of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention: has a short overall length, which is beneficial to better realizing the miniaturization of the device; has the characteristics of short focal length and wide angle, and the depth of field of the short focal length lens is relatively deep, and both the front and back of the subject can remain relatively clear; has a large field angle, providing a wider shooting field of view for lenses in scenarios such as video conferencing and capturing more image information; has a large imaging surface, which can be matched with a larger size chip to achieve high-definition imaging; has a large aperture, which is beneficial to increasing the light input of the lens and enabling the lens to achieve high-definition imaging in a dim environment.

[0089] In some embodiments, all seven lenses in the optical lens can be made of plastic lenses or adopt a structure with a combination of glass and plastic materials. Preferably, the optical lens of the present invention adopts a structure of seven lenses with a combination of glass and plastic, which can improve the thermal stability performance. Specifically, the first lens and the fourth lens can be made of glass lenses, and the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are all plastic lenses.

[0090] 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, in the optical lens provided by the present invention, the first lens and the fourth lens can adopt spherical lenses; the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens can adopt aspherical lenses.

[0091] In various embodiments of the present invention, when the lens adopts an aspherical lens, the surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0092]

[0093] 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 conic 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.

[0094] The present invention will be further described below with reference to several 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 tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0095] Example 1

[0096] Please see Figure 1 The figure shown is a schematic diagram 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 plane, the following components in sequence: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and a protective glass G2.

[0097] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0098] The second lens L2 has negative optical power, its object side S3 is concave, and its image side S4 is convex near the optical axis.

[0099] The third lens L3 has negative optical power, its object side S5 is concave, and its image side S6 is convex.

[0100] The fourth lens L4 has positive optical power, its object side S7 is convex, and its image side S8 is convex.

[0101] The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side S10 is convex.

[0102] The sixth lens L6 has negative optical power, its object side S11 is concave, and its image side S12 is concave.

[0103] The seventh lens L7 has negative optical power, its object side S13 is convex, and its image side S14 is concave.

[0104] Both the object side and image side of filter G1 are planar;

[0105] Both the object side and the image side of the protective glass G2 are flat.

[0106] The first lens L1 and the fourth lens L4 are glass spherical lenses; the second lens L2, the third lens L3, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all plastic aspherical lenses.

[0107] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0108] Table 1-1

[0109]

[0110]

[0111] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0112] Table 1-2

[0113] Face number K B C D E F G H S3 -2.83E+01 -8.33E-05 4.67E-05 -2.63E-06 7.68E-08 -1.07E-09 -1.29E-13 1.80E-15 S4 -8.49E+00 1.80E-03 1.07E-05 -2.36E-08 -9.26E-08 2.10E-09 1.62E-13 1.21E-14 S5 -2.29E+00 -2.96E-04 5.17E-07 3.38E-06 7.39E-08 -3.80E-09 1.89E-11 -7.30E-15 S6 -3.62E+00 -8.05E-04 5.47E-05 1.94E-06 1.87E-08 -2.48E-10 6.16E-11 0.00E+00 S9 5.99E+00 7.76E-04 -2.54E-04 4.82E-05 -1.47E-05 0.00E+00 0.00E+00 0.00E+00 S10 -6.25E-01 -2.59E-03 -1.29E-05 -5.61E-06 -5.70E-06 0.00E+00 0.00E+00 0.00E+00 S11 -4.29E+00 -5.72E-03 -2.38E-04 3.04E-05 -6.08E-06 0.00E+00 0.00E+00 0.00E+00 S12 2.24E+02 4.41E-03 -3.22E-04 3.10E-05 -1.68E-06 5.23E-10 0.00E+00 0.00E+00 S13 -2.61E+01 -7.02E-04 7.96E-05 -3.43E-06 5.54E-08 -2.64E-10 0.00E+00 0.00E+00 S14 -2.11E+01 -1.73E-03 6.79E-05 -1.55E-06 -6.80E-09 1.69E-10 0.00E+00 0.00E+00

[0114] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, relative illumination curve, and MTF curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown.

[0115] Figure 2 The F-Tan (Theta) distortion curve of Example 1 is shown, which represents the F-Tan (Theta) distortion of light 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-Tan (Theta) distortion of the optical lens is controlled within 0 to 20%, indicating that the optical lens 100 can correct distortion well.

[0116] Figure 3 The axial aberration curve of Embodiment 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 -1 mm to 2 mm, indicating that the optical lens 100 can correct the axial aberration well.

[0117] Figure 4 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 half-field 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 40% at the maximum half-field angle, indicating that the optical lens 100 has good relative illumination.

[0118] Figure 5The MTF 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 0.5 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, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0119] Example 2

[0120] Please see Figure 6 The figure shows 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 object side S5 of the third lens L3 is a convex surface; the image side S6 of the third lens L3 is a concave surface; the object side S9 of the fifth lens L5 is a concave surface; the object side S11 of the sixth lens L6 is a convex surface; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0121] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0122] Table 2-1

[0123]

[0124] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0125] Table 2-2

[0126]

[0127]

[0128] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, relative illumination curve, and MTF curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Figure 9 , Figure 10 As shown.

[0129] from Figure 7 As can be seen, the F-Tan (Theta) distortion of the optical lens is controlled within -20% to 0, indicating that the optical lens 200 can correct distortion well.

[0130] from Figure 8 As can be seen, the axial aberration offset is controlled within -2mm to 8mm, indicating that the optical lens 200 can correct axial aberration well.

[0131] from Figure 9 As can be seen, the relative illumination value of the optical lens is still greater than 40% at the maximum half field of view, indicating that the optical lens 200 has good relative illumination.

[0132] from Figure 10 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.

[0133] Example 3

[0134] Please see Figure 11 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.

[0135] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0136] Table 3-1

[0137]

[0138]

[0139] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0140] Table 3-2

[0141] Face number K B C D E F G H S3 -2.13E+01 1.04E-04 3.81E-05 -2.59E-06 8.19E-08 -1.25E-09 -1.29E-13 1.80E-15 S4 -2.41E+01 1.77E-03 6.36E-06 -2.68E-07 -7.75E-08 2.10E-09 1.62E-13 1.21E-14 S5 -2.64E+00 -4.74E-04 -1.17E-05 3.23E-06 9.20E-08 -3.80E-09 1.89E-11 -7.30E-15 S6 -3.78E+00 -9.15E-04 4.69E-05 1.58E-06 2.40E-08 -2.48E-10 6.16E-11 0.00E+00 S9 3.79E+00 6.82E-04 -2.72E-04 5.54E-05 -1.42E-05 0.00E+00 0.00E+00 0.00E+00 S10 -5.50E-01 -2.91E-03 1.32E-04 -1.59E-05 -4.75E-06 0.00E+00 0.00E+00 0.00E+00 S11 -4.06E+00 -5.47E-03 -2.04E-04 2.49E-05 -5.53E-06 0.00E+00 0.00E+00 0.00E+00 S12 3.78E+02 4.92E-03 -3.75E-04 3.27E-05 -1.68E-06 5.23E-10 0.00E+00 0.00E+00 S13 -2.49E+01 -8.10E-04 7.21E-05 -2.36E-06 4.13E-08 -2.64E-10 0.00E+00 0.00E+00 S14 -1.82E+01 -1.51E-03 5.26E-05 -1.12E-06 1.16E-09 1.69E-10 0.00E+00 0.00E+00

[0142] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, relative illumination curve, and MTF curve of the optical lens 300 are respectively as follows: Figure 12 , Figure 13 , Figure 14 , Figure 15 As shown.

[0143] from Figure 12 As can be seen, the F-Tan (Theta) distortion of the optical lens is controlled within 0-20%, indicating that the optical lens 300 can correct distortion well.

[0144] from Figure 13 As can be seen, the axial aberration offset is controlled within -1mm to 2mm, indicating that the optical lens 300 can effectively correct axial aberration.

[0145] from Figure 14 As can be seen, the relative illumination value of the optical lens is still greater than 50% at the maximum half field of view, indicating that the optical lens 300 has good relative illumination.

[0146] from Figure 15 As can be seen, the MTF value of this embodiment is above 0.5 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, and it has good imaging quality and good detail resolution in both low and high frequency conditions.

[0147] Please refer to Table 4 for the optical characteristics corresponding to each of 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.

[0148] Table 4

[0149]

[0150]

[0151] In summary, the optical lens provided by this invention employs seven lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power allocation, it can improve the imaging quality of the optical lens, reduce aberrations, and achieve low distortion and high resolution, thereby enhancing the image quality of the optical lens. It features short focal length and wide angle characteristics; the short focal length lens has a deeper depth of field, maintaining relative sharpness in both the foreground and background of the subject. It has a large field of view, providing a wider shooting field for scenarios such as video conferencing, capturing more image information. The use of a glass-plastic hybrid design helps reduce weight and cost, improves thermal stability, and minimizes temperature drift.

[0152] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," and "some examples" 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.

[0153] 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 successively 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 near the optical axis; A third lens with a negative optical power; A fourth lens with a positive optical power, whose object side is convex and whose image side is convex; A fifth lens with a positive optical power, whose image side is convex; A sixth lens with a negative optical power, whose image side is concave; A seventh lens with a negative optical power, whose object side is convex near the optical axis and whose image side is concave near the optical axis; Wherein, the curvature radius R3 of the object side of the second lens and the focal length f2 of the second lens satisfy: 0.18 < R3 / f2 < 0.48; the curvature radius R4 of the image side of the second lens and the focal length f2 of the second lens satisfy: 0.3 < R4 / f2 < 3.

2. The optical lens according to claim 1, characterized in that, The focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 0.4 < f4 / f5 < 1.

4.

3. The optical lens according to claim 1, characterized in that, The curvature radius R11 of the object side of the sixth lens and the focal length f6 of the sixth lens satisfy: -0.4 < R11 / f6 < .8; the curvature radius R12 of the image side of the sixth lens and the focal length f6 of the sixth lens satisfy: -11 < R12 / f6 < -0.

2.

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, the effective focal length f of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 38° < f×FOV / IH < 55°.

5. The optical lens according to claim 1, characterized in that, 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: 8.7° / mm < FOV / IH < 13° / mm.

6. The optical lens according to claim 1, characterized in that, The curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: -0.1 < R11 / R12 < 1.

8.

7. The optical lens according to claim 1, characterized in that, The curvature radius R1 of the object side of the first lens, the curvature radius R2 of the image side of the first lens, and the central thickness CT1 of the first lens satisfy: 1.9 < R1 / (R2 + CT1) < 2.

8.

8. The optical lens according to claim 1, characterized in that, The distance CT67 between the sixth lens and the seventh lens on the optical axis and the curvature radius R12 of the image side of the sixth lens satisfy: 0.01 < CT67 / R12 < 0.

9.

9. The optical lens according to claim 1, characterized in that, The clear aperture semi-diameter DM11 of the object side of the first lens and the focal length f1 of the first lens satisfy: 0.19 < DM11 / f1 < 0.

9.

10. The optical lens according to claim 1, characterized in that, The sagittal height SAG71 of the clear aperture of the object side of the seventh lens, the sagittal height SAG72 of the clear aperture of the image side of the seventh lens, and the central thickness CT7 of the seventh lens satisfy: -0.53 < (SAG72 - SAG71) / CT7 < -0.28.

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