Optical lens

Abstract

This application discloses an optical lens. The optical lens, along its optical axis from the object side to the image side, sequentially comprises: a first lens with negative optical power, its object side being convex and its image side being concave; a second lens with negative optical power, its object side being convex and its image side being concave; a third lens with negative optical power, its object side being concave and its image side being concave; a fourth lens with positive optical power, its object side being convex and its image side being concave; a fifth lens with positive optical power, its object side being convex and its image side being convex; a sixth lens with negative optical power, its image side being concave; a seventh lens with positive optical power, its object side being convex and its image side being convex; and an eighth lens with positive optical power, its object side being convex. The effective focal length F1 of the first lens and the effective focal length F of the optical lens satisfy: -8.8 ≤ F1 / F ≤ -7.7.

Description

Technical Field

[0001] This application relates to the field of optical components, and more specifically, to an optical lens. Background Technology

[0002] As online video becomes more and more widely used, users' demands for picture quality are gradually increasing.

[0003] Currently, video conferencing lenses on the market struggle to simultaneously achieve high specifications in terms of field of view and distortion, making it difficult to meet the requirements of various applications. The demand for high-resolution, low-distortion lenses continues to grow in the high-end market. Therefore, designing a compact, ultra-wide-angle, low-distortion fixed-focus lens has become a market trend. Summary of the Invention

[0004] This application provides an optical lens comprising, along the optical axis from the object side to the image side, the following components in sequence: a first lens with negative optical power, having a convex object side and a concave image side; a second lens with negative optical power, having a convex object side and a concave image side; a third lens with negative optical power, having a concave object side and a concave image side; a fourth lens with positive optical power, having a convex object side and a concave image side; a fifth lens with positive optical power, having a convex object side and a convex image side; a sixth lens with negative optical power, having a concave image side; a seventh lens with positive optical power, having a convex object side and a convex image side; and an eighth lens with positive optical power, having a convex object side; wherein the effective focal length F1 of the first lens and the effective focal length F of the optical lens satisfy: -8.8 ≤ F1 / F ≤ -7.7.

[0005] In one embodiment, the effective focal length F2 of the second lens and the effective focal length F of the optical lens satisfy: -3.0≤F2 / F≤-2.4.

[0006] In one embodiment, the effective focal length F3 of the third lens and the effective focal length F of the optical lens satisfy: -7.0≤F3 / F≤-3.7.

[0007] In one embodiment, the effective focal length F4 of the fourth lens and the effective focal length F of the optical lens satisfy: 4.6≤F4 / F≤5.6.

[0008] In one embodiment, the effective focal length F5 of the fifth lens and the effective focal length F of the optical lens satisfy: 1.3≤F5 / F≤2.0.

[0009] In one embodiment, the effective focal length F6 of the sixth lens and the effective focal length F of the optical lens satisfy: -4.3≤F6 / F≤-2.1.

[0010] In one embodiment, the effective focal length F7 of the seventh lens and the effective focal length F of the optical lens satisfy: 3.1≤F7 / F≤5.2.

[0011] In one embodiment, the effective focal length F8 of the eighth lens and the effective focal length F of the optical lens satisfy: 4.3≤F8 / F≤8.9.

[0012] In one embodiment, the effective focal length F of the optical lens and the radius of curvature R1 of the object side surface of the first lens satisfy: 0.1≤F / R1≤0.3.

[0013] In one embodiment, the combined focal length F12 of the first lens and the second lens and the combined focal length Fa of the first lens, the second lens, the third lens and the fourth lens satisfy: 0.7≤F12 / Fa≤1.5.

[0014] In one embodiment, the effective focal length F2 of the second lens and the radius of curvature R4 of the image-side surface of the second lens satisfy: -2.5≤F2 / R4≤-2.0.

[0015] In one embodiment, the air gap D23 between the second and third lenses on the optical axis and the distance TTL from the center of the object side of the first lens to the imaging surface of the optical lens on the optical axis satisfy: 0.1≤D23 / TTL≤0.2.

[0016] In one embodiment, the air gap D56 between the fifth and sixth lenses on the optical axis and the distance TTL from the center of the object side of the first lens to the imaging surface of the optical lens on the optical axis satisfy: 0≤D56 / TTL≤0.1.

[0017] In one embodiment, the first to eighth lenses each have a central thickness on the optical axis, and the minimum value dn and the maximum value dm of the central thickness satisfy: 0.1≤dn / dm≤0.5.

[0018] In one embodiment, the distance BFL from the center of the image side of the eighth lens to the imaging surface of the optical lens on the optical axis and the distance TTL from the center of the object side of the first lens to the imaging surface of the optical lens on the optical axis satisfy: 0.1≤BFL / TTL≤0.2.

[0019] In one embodiment, the distance TTL from the center of the object side of the first lens to the imaging plane of the optical lens on the optical axis satisfies the following condition: 0 ≤ F / TTL ≤ 0.2.

[0020] In another aspect, this application provides an electronic device. This electronic device includes an optical lens according to this application and an imaging element for converting an optical image formed by the optical lens into an electrical signal.

[0021] This application employs eight lenses. By optimizing the shape, optical power, and other relevant parameters of each lens, the optical lens achieves at least one beneficial effect, such as a large field of view, low distortion, high relative illumination, and miniaturization. Attached Figure Description

[0022] Other features, objects, and advantages of this utility application will become more apparent from the following detailed description of the embodiments, taken in conjunction with the accompanying drawings. In the drawings:

[0023] Figure 1 This is a schematic diagram illustrating the structure of an optical lens according to Embodiment 1 of this application;

[0024] Figure 2 To illustrate the distortion curve of the optical lens according to Embodiment 1 of this application;

[0025] Figure 3 To illustrate the structure of the optical lens according to Embodiment 2 of this application;

[0026] Figure 4 To illustrate the distortion curve of the optical lens according to Embodiment 2 of this application;

[0027] Figure 5 To illustrate the structure of the optical lens according to Embodiment 3 of this application;

[0028] Figure 6 To illustrate the distortion curve of the optical lens according to Embodiment 3 of this application;

[0029] Figure 7 To illustrate the structural schematic diagram of the optical lens according to Embodiment 4 of this application; and

[0030] Figure 8 To illustrate the distortion curve of the optical lens according to Embodiment 4 of this application. Detailed Implementation

[0031] To facilitate understanding of this application, a more complete description of the application will be provided below with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of the application and are not intended to limit the scope of the 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.

[0032] 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 this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0033] 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.

[0034] 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 side is called the image-side surface of the lens.

[0035] 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.

[0036] 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 a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0037] 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.

[0038] The features, principles and other aspects of this application are described in detail below.

[0039] In an exemplary embodiment, the optical lens includes, for example, eight lenses with optical power, namely a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. These eight lenses are arranged sequentially along the optical axis from the object side to the image side, and any two adjacent lenses among the first to eighth lenses may have a gap distance between them.

[0040] In an exemplary embodiment, the optical lens may further include a photosensitive element disposed on the image side of the eighth lens. Optionally, the photosensitive element disposed on the image side of the eighth lens may be a photosensitive coupling element (CCD) or a complementary metal oxide semiconductor element (CMOS).

[0041] In an exemplary embodiment, an aperture stop may be provided between the fourth and fifth lenses to limit the light beam and further improve the imaging quality of the optical lens. The aperture stop helps to concentrate the light entering the optical lens, reduce the maximum aperture of the optical lens, and decrease the assembly sensitivity of the system. In this embodiment, the aperture stop may be located near the object side of the fifth lens. However, it should be noted that the location of the aperture stop disclosed herein is merely an example and not a limitation; in alternative embodiments, the aperture stop may be located at other positions as needed.

[0042] In an exemplary embodiment, the first lens has negative optical power, with its object-side surface being convex and its image-side surface being concave. The negative optical power and convex object-side surface of the first lens allow for the collection of light rays from a large field of view into the rear optical system, effectively increasing light transmission and fixing the direction of large-angle light rays at the edges. The concave image-side surface prevents excessive divergence of object-side light rays, which is beneficial for controlling the aperture of the rear lenses.

[0043] In an exemplary embodiment, the second lens has negative optical power, with its object-side surface being convex and its image-side surface being concave. The negative optical power and convex object-side surface of the second lens effectively converge light rays to prevent excessive divergence; the concave image-side surface allows the light rays exiting the second lens to be smoother, which in turn helps control the aperture of the rear lens.

[0044] In an exemplary embodiment, the first lens and the second lens are both designed as meniscus lenses with negative optical power. When combined, they can make the outgoing light rays smoother, which is beneficial for achieving small distortion.

[0045] In an exemplary embodiment, the third lens has negative optical power, and both its object-side and image-side surfaces are concave. The negative optical power of the third lens allows it to collect light rays entering through the second lens, resulting in a smooth transition of light paths. The concave object-side surface allows the light rays transmitted from the second lens to diverge after passing through the object-side surface of the third lens, causing the light rays at the rear to converge slowly. Furthermore, it causes the light rays at the edge of the field of view to exhibit an upward trend, which is beneficial for achieving a matching effect with large chips, thereby obtaining a larger image.

[0046] In an exemplary embodiment, the fourth lens has positive optical power, with its object-side surface being convex and its image-side surface being concave. This configuration of the fourth lens can effectively converge light rays, and together with the third lens having negative optical power, it facilitates the smooth entry of light rays into the rear lenses, thereby improving resolution.

[0047] In an exemplary embodiment, the fifth lens has positive optical power, with both its object-side and image-side surfaces being convex. This configuration of the fifth lens facilitates light convergence; simultaneously, it compresses the angle of the incident light rays, allowing for a smooth transition and enabling diverging light rays to smoothly enter the rear, further smoothing the light path and facilitating a reduction in the aperture of the rear lens.

[0048] In an exemplary embodiment, the sixth lens has negative optical power and its image-side surface is concave. This arrangement of the sixth lens can collect light rays entering through the fifth lens, allowing for a smooth transition in light path; its concave image-side surface helps to make the light rays trend upwards, thereby expanding the imaging range.

[0049] In an exemplary embodiment, the seventh lens has positive optical power, and its object-side surface is convex, as is its image-side surface. This configuration of the seventh lens allows diverging light rays to converge smoothly into the rear lens after passing through the seventh lens, further smoothing the transition of light paths, which is beneficial for improving astigmatism and field curvature in imaging, and enhancing the resolving power of the optical lens.

[0050] In an exemplary embodiment, the eighth lens has positive optical power and its object-side surface is convex. The positive optical power and convex object-side surface of the eighth lens allow light rays passing through the preceding lens to smoothly transition to the imaging plane, reducing the overall optical length, correcting astigmatism and field curvature, and improving resolution. The eighth lens may be a freeform surface lens to further correct edge distortion and improve resolution.

[0051] In an exemplary embodiment, the optical lens according to this application satisfies: -8.8 ≤ F1 / F ≤ -7.7, where F1 is the effective focal length of the first lens and F is the effective focal length of the optical lens. Satisfying -8.8 ≤ F1 / F ≤ -7.7 optimizes the optical power of the first lens, which is beneficial for light rays with a large field of view to enter the optical lens.

[0052] In an exemplary embodiment, the optical lens according to this application satisfies: -3.0 ≤ F2 / F ≤ -2.4, where F2 is the effective focal length of the second lens and F is the effective focal length of the optical lens. Satisfying -3.0 ≤ F2 / F ≤ -2.4 optimizes the optical power of the second lens, collects light rays entering through the first lens, helps to smooth the path of forward light rays, and improves resolving power.

[0053] In an exemplary embodiment, the optical lens according to this application satisfies: -7.0 ≤ F3 / F ≤ -3.7, where F3 is the effective focal length of the third lens and F is the effective focal length of the optical lens. Satisfying -7.0 ≤ F3 / F ≤ -3.7, the third lens has negative optical power, controlling the direction of light, which helps to reduce the rear aperture of the optical lens and achieve miniaturization of the optical lens.

[0054] In an exemplary embodiment, the optical lens according to this application satisfies: 4.6 ≤ F4 / F ≤ 5.6, where F4 is the effective focal length of the fourth lens and F is the effective focal length of the optical lens. Satisfying 4.6 ≤ F4 / F ≤ 5.6 allows the fourth lens to further converge light rays, ensuring a smooth transition of light rays after passing through the third and fourth lenses to the rear lens, thus improving resolving power. Simultaneously, the converging effect of the fourth lens further reduces the rear aperture of the optical lens, facilitating miniaturization.

[0055] In an exemplary embodiment, the optical lens according to this application satisfies: 1.3 ≤ F5 / F ≤ 2.0, where F5 is the effective focal length of the fifth lens and F is the effective focal length of the optical lens. Satisfying 1.3 ≤ F5 / F ≤ 2.0 helps the optical lens absorb more light and improve relative illumination.

[0056] In an exemplary embodiment, the optical lens according to this application satisfies: -4.3 ≤ F6 / F ≤ -2.1, where F6 is the effective focal length of the sixth lens and F is the effective focal length of the optical lens. Satisfying -4.3 ≤ F6 / F ≤ -2.1 helps to smoothly transition light and reduces the sensitivity of the optical lens.

[0057] In an exemplary embodiment, the optical lens according to this application satisfies: 3.1≤F7 / F≤5.2, where F7 is the effective focal length of the seventh lens and F is the effective focal length of the optical lens. Satisfying 3.1≤F7 / F≤5.2 and reasonably setting the optical power of the seventh lens helps to balance various aberrations of the optical lens.

[0058] In an exemplary embodiment, the optical lens according to this application satisfies: 4.3≤F8 / F≤8.9, where F8 is the effective focal length of the eighth lens and F is the effective focal length of the optical lens. Satisfying 4.3≤F8 / F≤8.9 facilitates the smooth entry of light into the rear optical system, helps compensate for the positive distortion introduced by the seventh lens, and can further correct various aberrations generated by the front lens group.

[0059] In an exemplary embodiment, the optical lens according to this application satisfies: 0.1≤F / R1≤0.3, where F is the effective focal length of the optical lens and R1 is the radius of curvature of the object-side surface of the first lens. Satisfying 0.1≤F / R1≤0.3 can avoid the object-side surface radius of curvature of the first lens being too small, thereby effectively avoiding the generation of aberrations when light is incident, and is also beneficial to the fabrication and shaping of the first lens.

[0060] In an exemplary embodiment, the optical lens according to this application satisfies 0.7≤F12 / Fa≤1.5, where F12 is the combined focal length of the first and second lenses, and Fa is the combined focal length of the first, second, third, and fourth lenses. Satisfying 0.7≤F12 / Fa≤1.5 allows for control of the light path between the first and fourth lenses, reducing aberrations caused by large-angle light rays entering through the first lens, and simultaneously making the lens structure more compact, which is beneficial for the miniaturization of the optical lens.

[0061] In an exemplary embodiment, the optical lens according to this application satisfies: -2.5 ≤ F2 / R4 ≤ -2.0, where F2 is the effective focal length of the second lens and R4 is the radius of curvature of the image-side surface of the second lens. By satisfying -2.5 ≤ F2 / R4 ≤ -2.0, the effective focal length of the second lens and its radius of curvature of the image-side surface are reasonably controlled. When the image-side surface of the second lens is formed as a concave surface, the optical power of the second lens can be made negative. This is beneficial for collecting light rays entering through the first lens, avoiding excessive divergence of object-side light rays, and is beneficial for controlling the aperture of the rear lens.

[0062] In an exemplary embodiment, the optical lens according to this application satisfies: 0.1 ≤ D23 / TTL ≤ 0.2, where D23 is the air gap between the second and third lenses on the optical axis, and TTL is the distance on the optical axis from the center of the object-side surface of the first lens to the imaging surface of the optical lens. Satisfying 0.1 ≤ D23 / TTL ≤ 0.2 allows light to enter the third lens smoothly, helping to reduce ghosting caused by the distance between the second and third lenses.

[0063] In an exemplary embodiment, the optical lens according to this application satisfies: 0 ≤ D56 / TTL ≤ 0.1, where D56 is the air gap between the fifth and sixth lenses on the optical axis, and TTL is the distance on the optical axis from the center of the object side of the first lens to the imaging surface of the optical lens. Satisfying 0 ≤ D56 / TTL ≤ 0.1 is beneficial for improving ghosting and also facilitates lens assembly.

[0064] In an exemplary embodiment, the first to eighth lenses each have a central thickness on the optical axis, and the minimum value dn and the maximum value dm of the central thickness satisfy: 0.1 ≤ dn / dm ≤ 0.5. Satisfying 0.1 ≤ dn / dm ≤ 0.5 is beneficial for optimizing the parameters of each lens in the optical lens, making the central thickness of each lens uniform and the function of each lens stable.

[0065] In an exemplary embodiment, the optical lens according to this application satisfies: 0.1 ≤ BFL / TTL ≤ 0.2, where BFL is the distance on the optical axis from the center of the image-side surface of the eighth lens to the imaging surface of the optical lens, and TTL is the distance on the optical axis from the center of the object-side surface of the first lens to the imaging surface of the optical lens. Satisfying 0.1 ≤ BFL / TTL ≤ 0.2 is beneficial for achieving a long back focal length while realizing miniaturization. This is beneficial for module assembly, and controlling the back focal length within a reasonable range also helps reduce the energy of ghost images generated by reflections from the center of the lenses and color filters.

[0066] In an exemplary embodiment, the optical lens according to this application satisfies: 0 ≤ F / TTL ≤ 0.2, where TTL is the distance on the optical axis from the center of the object-side surface of the first lens to the imaging surface of the optical lens, and F is the effective focal length of the optical lens. Satisfying 0 ≤ F / TTL ≤ 0.2 can effectively limit the length of the lens, which is beneficial for achieving lens miniaturization.

[0067] In an exemplary embodiment, the optical lens of this application has the characteristic of a large field of view, with a maximum field of view of up to 130°, which is beneficial for the optical lens to achieve wide-angle characteristics, thereby enabling the acquisition of more scene information.

[0068] In an exemplary embodiment, the optical lens of this application satisfies the wide-angle characteristic while achieving a distortion value as low as 1%, ensuring the authenticity of the image.

[0069] In an exemplary embodiment, the optical lens of this application has high relative illumination, with a relative illumination of at least 75%, which ensures the transparency and uniformity of the brightness of the image, and there will be no dark corners even at the edges of the image.

[0070] In an exemplary embodiment, the optical lens of this application may, as needed, include a filter and / or protective glass disposed between the eighth lens and the imaging surface to filter light of different wavelengths and prevent damage to the image-side elements (e.g., chips) of the optical lens.

[0071] In an exemplary embodiment, the first to eighth lenses can be spherical lenses or aspherical lenses. This application does not specifically limit the number of spherical and aspherical lenses; when image quality is a primary concern, the number of aspherical lenses can be increased, and even all lenses can be aspherical. Aspherical lenses are characterized by a continuously changing curvature from the lens center to the periphery. Unlike spherical lenses, which have a constant curvature from the lens center to the periphery, aspherical lenses have better radius of curvature characteristics, offering advantages in improving distortion aberrations and astigmatism. Using aspherical lenses can minimize aberrations that occur during imaging, thereby improving the lens's image quality. Optionally, at least one of the object-side and image-side surfaces of each of the first to eighth lenses is an aspherical mirror surface.

[0072] In an exemplary embodiment, the first and fifth lenses are spherical mirrors; the object-side and image-side surfaces of each of the second, third, fourth, sixth, seventh, and eighth lenses are aspherical mirrors. Specifically, the object-side and image-side surfaces of the third and / or eighth lenses can be freeform surfaces.

[0073] The optical lens of this application can employ freeform surface lenses. By rationally designing the freeform surface and combining its surface shape and material, the lens can better correct system edge distortion values ​​and balance various aberrations without increasing the number of lenses or the overall length, while simultaneously meeting the requirements for wide-angle and low-distortion performance. For example, the third lens and / or the eighth lens in the optical lens of this application employ freeform surface lenses.

[0074] However, those skilled in the art will understand that the number of lenses constituting the lens can be varied to obtain the various results and advantages described in this specification without departing from the technical solutions claimed in this application. For example, although eight lenses are described as an example in the embodiments, the optical lens is not limited to including eight lenses. If desired, the optical lens may also include other numbers of lenses. Specific embodiments of the optical lens applicable to the above embodiments are further described below with reference to the accompanying drawings.

[0075] Example 1

[0076] The following is for reference Figure 1 An optical lens according to Embodiment 1 of this application is described. Figure 1 A schematic diagram of the structure of an optical lens according to Embodiment 1 of this application is shown.

[0077] like Figure 1 As shown, the optical lens includes, in sequence from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 along the optical axis.

[0078] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0079] The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave.

[0080] The third lens L3 has negative optical power, and its object side S5 is concave, as is its image side S6.

[0081] The fourth lens L4 has positive optical power, with its object side S7 being convex and its image side S8 being concave.

[0082] The fifth lens L5 has positive optical power, and its object side S9 is convex, and its image side S10 is convex.

[0083] The sixth lens L6 has negative optical power, with its object side S11 being convex and its image side S12 being concave.

[0084] The seventh lens L7 has positive optical power, and its object side S13 is convex, and its image side S14 is convex.

[0085] The eighth lens L8 has positive optical power, with its object side S15 being convex and its image side S16 being concave.

[0086] The optical lens may also include an aperture stop STO, which may be positioned between the fourth lens L4 and the fifth lens L5 to improve image quality.

[0087] Optionally, the optical lens may also include a filter CG having an object-side surface S17 and an image-side surface S18 and / or a protective glass (not shown) having both an object-side surface and an image-side surface. The filter CG and / or the protective glass can be used to correct color aberrations, and can also be used to protect the image sensor chip IMA located at the imaging surface. Light from the object passes sequentially through each surface S1 to S18 and is ultimately imaged onto the imaging surface.

[0088] Table 1-1 shows the radius of curvature, thickness / distance, refractive index, and Abbe number of each lens in the optical lens of Example 1, wherein the units of radius of curvature and thickness / distance are millimeters (mm).

[0089]

[0090] Table 1-1

[0091] In Example 1, the first and fifth lenses are spherical lenses. The object-side and image-side surfaces of any one of the second, third, fourth, sixth, seventh, and eighth lenses are aspherical. Specifically, the second, third, fourth, sixth, and seventh lenses are conventional aspherical lenses, and the surface shape of each conventional aspherical lens is... The following aspherical formulas can be used for limitation:

[0092] (1)

[0093] in, For an aspherical surface along the optical axis at a height of h When the position is such that the distance from the vertex of the aspherical surface is the sag; c For the paraxial curvature of an aspherical surface, c =1 / R (i.e., paraxial curvature) c (The reciprocal of the radius of curvature R in Table 1 above). k The conic coefficient; Ai Is it an aspherical first i -th order correction coefficients.

[0094] The object-side and image-side surfaces of the eighth lens are freeform surfaces, more specifically, Zernike edge-sagittary surfaces. Zernike edge-sagittary surfaces are defined by even-order aspherical surfaces (supporting planes, spheres, quadric surfaces, and polynomial aspherical surfaces) plus some additional aspherical conditions determined by the Zernike edge coefficients. The surface sagittary form is:

[0095]

[0096] Where N is the index of the Zernike coefficient in the series. Ai ρ is the coefficient of the i-th Zernike marginal polynomial, r is the radial ray coordinate, and ρ is the normalized radial ray coordinate. These are the coordinates of a ray, expressed in angles.

[0097] Table 1-2 below shows the higher-order coefficients of S3-S8 and S11-S14 for each conventional aspherical mirror in Example 1. A 4 , A 6 , A 8 , A 10 , A 12 and A 14 .

[0098]

[0099] Table 1-2

[0100] Tables 1-3 below show the higher-order coefficients of the Zernike edge sagittal surfaces S15 and S16 that can be used in Example 1.

[0101]

[0102] Table 1-3

[0103] In this embodiment, the absolute value of optical distortion of the optical lens is 3.0%. Figure 2 The distortion curve of the optical lens of Embodiment 1 is shown, representing the distortion magnitude values ​​corresponding to different image heights. According to... Figure 2 It can be seen that the optical lens given in Example 1 can achieve good imaging quality.

[0104] Example 2

[0105] The following is for reference Figure 3 An optical lens according to Embodiment 2 of this application is described. In this embodiment and the following embodiments, for the sake of brevity, descriptions similar to those in Embodiment 1 will be omitted. Figure 3 A schematic diagram of the structure of an optical lens according to Embodiment 2 of this application is shown.

[0106] like Figure 3 As shown, the optical lens includes, in sequence from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 along the optical axis.

[0107] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0108] The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave.

[0109] The third lens L3 has negative optical power, and its object side S5 is concave, as is its image side S6.

[0110] The fourth lens L4 has positive optical power, with its object side S7 being convex and its image side S8 being concave.

[0111] The fifth lens L5 has positive optical power, and its object side S9 is convex, and its image side S10 is convex.

[0112] The sixth lens L6 has negative optical power, and its object side S11 is concave, and its image side S12 is concave.

[0113] The seventh lens L7 has positive optical power, and its object side S13 is convex, and its image side S14 is convex.

[0114] The eighth lens L8 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0115] The optical lens may also include an aperture stop STO, which may be positioned between the fourth lens L4 and the fifth lens L5 to improve image quality.

[0116] Optionally, the optical lens may also include a filter CG having an object-side surface S17 and an image-side surface S18 and / or a protective glass (not shown) having both an object-side surface and an image-side surface. The filter CG and / or the protective glass can be used to correct color aberrations, and can also be used to protect the image sensor chip IMA located at the imaging surface. Light from the object passes sequentially through each surface S1 to S18 and is ultimately imaged onto the imaging surface.

[0117] Table 2-1 shows the radius of curvature, thickness / distance, refractive index, and Abbe number of each lens in the optical lens of Example 2, wherein the units of radius of curvature and thickness / distance are millimeters (mm).

[0118]

[0119] Table 2-1

[0120] In Example 2, the first and fifth lenses are spherical lenses. The object-side and image-side surfaces of any one of the second, third, fourth, sixth, seventh, and eighth lenses are aspherical. Among them, the second, fourth, sixth, and seventh lenses are conventional aspherical lenses, and the third and eighth lenses are Zernike edge-sagittar surfaces. Table 2-2 shows the higher-order coefficients that can be used for each conventional aspherical lens in Example 2. Each conventional aspherical surface can be defined by formula (1) given in Example 1 above. Table 2-3 shows the higher-order coefficients that can be used for each Zernike edge-sagittar surface in Example 2. Each Zernike edge-sagittar surface can be defined by formula (2) given in Example 1 above.

[0121]

[0122] Table 2-2

[0123]

[0124] Table 2-3

[0125] In this embodiment, the absolute value of optical distortion of the optical lens is 1.2%. Figure 4 The distortion curve of the optical lens of Embodiment 2 is shown, representing the distortion magnitude values ​​corresponding to different image heights. According to... Figure 4It can be seen that the optical lens given in Example 2 can achieve good imaging quality.

[0126] Example 3

[0127] The following is for reference Figure 5 An optical lens according to Embodiment 3 of this application is described. Figure 5 A schematic diagram of the structure of an optical lens according to Embodiment 3 of this application is shown.

[0128] like Figure 5 As shown, the optical lens includes, in sequence from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 along the optical axis.

[0129] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0130] The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave.

[0131] The third lens L3 has negative optical power, and its object side S5 is concave, as is its image side S6.

[0132] The fourth lens L4 has positive optical power, with its object side S7 being convex and its image side S8 being concave.

[0133] The fifth lens L5 has positive optical power, and its object side S9 is convex, and its image side S10 is convex.

[0134] The sixth lens L6 has negative optical power, and its object side S11 is concave, and its image side S12 is concave.

[0135] The seventh lens L7 has positive optical power, and its object side S13 is convex, and its image side S14 is convex.

[0136] The eighth lens L8 has positive optical power, with its object side S15 being convex and its image side S16 being concave.

[0137] The optical lens may also include an aperture stop STO, which may be positioned between the fourth lens L4 and the fifth lens L5 to improve image quality.

[0138] Optionally, the optical lens may also include a filter CG having an object-side surface S17 and an image-side surface S18 and / or a protective glass (not shown) having both an object-side surface and an image-side surface. The filter CG and / or the protective glass can be used to correct color aberrations, and can also be used to protect the image sensor chip IMA located at the imaging surface. Light from the object passes sequentially through each surface S1 to S18 and is ultimately imaged onto the imaging surface.

[0139] Table 3-1 shows the radius of curvature, thickness / distance, refractive index, and Abbe number of each lens in the optical lens of Example 3, wherein the units of radius of curvature and thickness / distance are millimeters (mm).

[0140]

[0141] Table 3-1

[0142] In Example 3, the first and fifth lenses are spherical lenses. The object-side and image-side surfaces of any one of the second, third, fourth, sixth, seventh, and eighth lenses are aspherical. The second, fourth, sixth, seventh, and eighth lenses are conventional aspherical lenses. Table 3-2 shows the higher-order coefficients applicable to each conventional aspherical lens in Example 3. Each conventional aspherical surface can be defined by formula (1) given in Example 1 above. The third lens is a freeform surface, more specifically an extended polynomial surface. Table 3-3 shows the higher-order coefficients applicable to each extended polynomial surface in Example 3. Each extended polynomial surface supports a base quadratic aspherical surface plus a polynomial aspherical surface. The extended polynomial surface sag is defined as:

[0143]

[0144] Where N is the total number of polynomial coefficients in the series. Ai These are the coefficients of the i-th extended polynomial. This polynomial is simply a power series in the x and y directions. The first term is x, then y, then x... x, x y, y y, etc. There are 2 terms of degree 1, 3 terms of degree 2, 4 terms of degree 3, and so on, with the highest degree being 20, making the maximum total number of polynomial aspherical coefficients 230. The data values ​​at positions such as x and y are divided by a normalized radius to obtain a dimensionless polynomial coefficient.

[0145]

[0146] Table 3-2

[0147]

[0148] Table 3-3

[0149] In this embodiment, the absolute value of optical distortion of the optical lens is 3.2%. Figure 6 The distortion curve of the optical lens of Embodiment 3 is shown, representing the distortion magnitude corresponding to different image heights. According to... Figure 6It can be seen that the optical lens given in Example 3 can achieve good imaging quality.

[0150] Example 4

[0151] The following is for reference Figure 7 An optical lens according to Embodiment 4 of this application is described. Figure 7 A schematic diagram of the structure of an optical lens according to Embodiment 4 of this application is shown.

[0152] like Figure 7 As shown, the optical lens includes, in sequence from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 along the optical axis.

[0153] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0154] The second lens L2 has negative optical power, its object side S3 is convex, and its image side S4 is concave.

[0155] The third lens L3 has negative optical power, and its object side S5 is concave, as is its image side S6.

[0156] The fourth lens L4 has positive optical power, with its object side S7 being convex and its image side S8 being concave.

[0157] The fifth lens L5 has positive optical power, and its object side S9 is convex, and its image side S10 is convex.

[0158] The sixth lens L6 has negative optical power, with its object side S11 being convex and its image side S12 being concave.

[0159] The seventh lens L7 has positive optical power, and its object side S13 is convex, and its image side S14 is convex.

[0160] The eighth lens L8 has positive optical power, with its object side S15 being convex and its image side S16 being concave.

[0161] The optical lens may also include an aperture stop STO, which may be positioned between the fourth lens L4 and the fifth lens L5 to improve image quality.

[0162] Optionally, the optical lens may also include a filter CG having an object-side surface S17 and an image-side surface S18 and / or a protective glass (not shown) having both an object-side surface and an image-side surface. The filter CG and / or the protective glass can be used to correct color aberrations, and can also be used to protect the image sensor chip IMA located at the imaging surface. Light from the object passes sequentially through each surface S1 to S18 and is ultimately imaged onto the imaging surface.

[0163] Table 4-1 shows the radius of curvature, thickness / distance, refractive index, and Abbe number of each lens in the optical lens of Example 4, wherein the units of radius of curvature and thickness / distance are millimeters (mm).

[0164]

[0165] Table 4-1

[0166] In Example 4, the first and fifth lenses are spherical lenses. The object-side and image-side surfaces of any one of the second, third, fourth, sixth, seventh, and eighth lenses are aspherical. Among them, the second, third, fourth, sixth, and seventh lenses are conventional aspherical lenses, and the eighth lens is a Zernike edge-sagittar surface. Table 2-2 shows the higher-order coefficients that can be used for each conventional aspherical lens in Example 4. Each conventional aspherical surface can be defined by formula (1) given in Example 1 above. Table 2-3 shows the higher-order coefficients that can be used for each Zernike edge-sagittar surface in Example 4. Each Zernike edge-sagittar surface can be defined by formula (2) given in Example 1 above.

[0167]

[0168] Table 4-2

[0169]

[0170] Table 4-3

[0171] In this embodiment, the absolute value of optical distortion of the optical lens is 1.0%. Figure 8 The distortion curve of the optical lens of Example 4 is shown, representing the distortion magnitude corresponding to different image heights. According to... Figure 8 It can be seen that the optical lens given in Example 4 can achieve good imaging quality.

[0172] In summary, Examples 1 to 4 satisfy the relationships shown in Table 5 below.

[0173]

[0174] Table 5

[0175] This application also provides an electronic device that may include an optical lens according to the above embodiments of this application and an imaging element for converting an optical image formed by the optical lens into an electrical signal. The electronic device may be a stand-alone electronic device, such as a rangefinder camera, or an imaging module integrated into a rangefinder device. Furthermore, the electronic device may also be a stand-alone imaging device, such as an in-vehicle camera, or an imaging module integrated into a driver assistance system, such as a vehicle-mounted camera.

[0176] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical lens, characterized in that, The optical lens comprises, along the optical axis from the object side to the image side, the following in sequence: The first lens with negative optical power has a convex object side and a concave image side. A second lens with negative optical power has a convex object side and a concave image side. A third lens with negative optical power has a concave object side and a concave image side. The fourth lens with positive optical power has a convex object side and a concave image side. A fifth lens with positive optical power, having a convex object-side surface and a convex image-side surface; and The sixth lens has negative optical power and its image-side surface is concave. The seventh lens with positive optical power has a convex object-side surface and a convex image-side surface. The eighth lens, which has positive optical power, has a convex object-side surface; The effective focal length F1 of the first lens and the effective focal length F of the optical lens satisfy: -8.8 ≤ F1 / F ≤ -7.7; The effective focal length F4 of the fourth lens and the effective focal length F of the optical lens satisfy the following condition: 4.6 ≤ F4 / F ≤ 5.6; The optical lens has eight lenses with optical power.

2. The optical lens according to claim 1, wherein, The effective focal length F2 of the second lens and the effective focal length F of the optical lens satisfy: -3.0≤F2 / F≤-2.

4.

3. The optical lens according to claim 1, wherein, The effective focal length F3 of the third lens and the effective focal length F of the optical lens satisfy the following condition: -7.0≤F3 / F≤-3.

7.

4. The optical lens according to claim 1, wherein, The effective focal length F5 of the fifth lens and the effective focal length F of the optical lens satisfy the following condition: 1.3≤F5 / F≤2.

0.

5. The optical lens according to claim 1, wherein, The effective focal length F6 of the sixth lens and the effective focal length F of the optical lens satisfy the following condition: -4.3≤F6 / F≤-2.

1.

6. The optical lens according to claim 1, wherein, The effective focal length F7 of the seventh lens and the effective focal length F of the optical lens satisfy the following condition: 3.1≤F7 / F≤5.

2.

7. The optical lens according to claim 1, wherein, The effective focal length F8 of the eighth lens and the effective focal length F of the optical lens satisfy the following condition: 4.3≤F8 / F≤8.

9.

8. The optical lens according to any one of claims 1-7, wherein, The effective focal length F of the optical lens and the radius of curvature R1 of the object side surface of the first lens satisfy the condition: 0.1≤F / R1≤0.

3.

9. The optical lens according to any one of claims 1-7, wherein, The combined focal length F12 of the first lens and the second lens and the combined focal length Fa of the first lens, the second lens, the third lens and the fourth lens satisfy: 0.7≤F12 / Fa≤1.

5.

10. The optical lens according to any one of claims 1-7, wherein, The effective focal length F2 of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: -2.5≤F2 / R4≤-2.

0.

11. The optical lens according to any one of claims 1-7, wherein, The air gap D23 between the second lens and the third lens on the optical axis and the distance TTL from the center of the object side of the first lens to the imaging surface of the optical lens on the optical axis satisfy: 0.1≤D23 / TTL≤0.

2.

12. The optical lens according to any one of claims 1-7, wherein, The air gap D56 between the fifth lens and the sixth lens on the optical axis and the distance TTL from the center of the object side of the first lens to the imaging surface of the optical lens on the optical axis satisfy the following condition: 0 ≤ D56 / TTL ≤ 0.

1.

13. The optical lens according to any one of claims 1-7, wherein, The first lens to the eighth lens each have a central thickness on the optical axis, and the minimum value dn and the maximum value dm of the central thickness satisfy: 0.1≤dn / dm≤0.

5.

14. The optical lens according to any one of claims 1-7, wherein, The distance BFL from the center of the image side of the eighth lens to the imaging surface of the optical lens on the optical axis and the distance TTL from the center of the object side of the first lens to the imaging surface of the optical lens on the optical axis satisfy the following condition: 0.1 ≤ BFL / TTL ≤ 0.

2.

15. The optical lens according to any one of claims 1-7, wherein, The distance TTL from the center of the object side of the first lens to the imaging surface of the optical lens on the optical axis satisfies the following condition: 0 ≤ F / TTL ≤ 0.

2.

16. The optical lens according to claim 1, wherein, The optical lens satisfies any one of the following conditions: -8.695≤F1 / F≤-7.984, -2.644≤F² / F≤-2.506 -5.912≤F3 / F≤-3.810, 4.712≤F4 / F≤5.433 1.483≤F5 / F≤1.897 -4.164≤F6 / F≤-2.377, 3.218≤F7 / F≤5.098 4.374≤F8 / F≤8.790 0.167≤F / R1≤0.204, 0.966≤F12 / Fa≤1.382, -2.430≤F² / R⁴≤-2.063, 0.113≤D23 / TTL≤0.154; 0.004≤D56 / TTL≤0.021 0.179≤dn / dm≤0.391, 0.122≤BFL / TTL≤0.131 0.100≤F / TTL≤0.113 Wherein, F1 is the effective focal length of the first lens, F is the effective focal length of the optical lens, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, F4 is the effective focal length of the fourth lens, F5 is the effective focal length of the fifth lens, F6 is the effective focal length of the sixth lens, F7 is the effective focal length of the seventh lens, F8 is the effective focal length of the eighth lens, R1 is the radius of curvature of the object-side surface of the first lens, F12 is the combined focal length of the first lens and the second lens, and Fa is the combined focal length of the first lens, the second lens, the third lens, and the fourth lens. Focal length, R4 is the radius of curvature of the image-side surface of the second lens, D23 is the air gap between the second lens and the third lens on the optical axis, D56 is the air gap between the fifth lens and the sixth lens on the optical axis, TTL is the distance from the center of the object-side surface of the first lens to the imaging surface of the optical lens on the optical axis, the first lens to the eighth lens each have a center thickness on the optical axis, dn is the minimum value of the center thickness, dm is the maximum value of the center thickness, and BFL is the distance from the center of the image-side surface of the eighth lens to the imaging surface of the optical lens on the optical axis.

Images