Optical lens

Abstract

The application discloses an optical lens, which comprises, in sequence from an object side to an image side along an optical axis, a first lens with negative refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens, a fifth lens with a convex object side, a sixth lens with positive refractive power, a seventh lens with negative refractive power, and an eighth lens with positive refractive power; wherein the fifth lens and the sixth lens are glued together to form a double-glued lens; the maximum field of view angle of the optical lens corresponds to an image height H, and the entrance pupil diameter ENPD of the optical lens satisfies 2.7≤H / ENPD≤3.7.

Description

Technical Field

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

[0002] Wide-angle lenses, with their large field of view and wide shooting range, are widely used in security, automotive, video conferencing, smart home, and many other fields. With the widespread application of wide-angle lenses, higher demands are being placed on them. For example, they must remain in focus under large temperature differences, function effectively both day and night to meet shooting needs, and simultaneously meet the requirements of low cost and miniaturization.

[0003] Existing wide-angle lenses are usually composed of multiple lenses. When the lens design of a wide-angle lens is not reasonable, it is difficult to meet the requirements of a large aperture while also taking into account the visible light and infrared bands, as well as low cost, small size, and non-defocusing under conditions of large temperature differences. Summary of the Invention

[0004] This application provides an optical lens comprising, in sequence along the optical axis from the object side to the image side: a first lens having negative optical power, being a meniscus lens with a convex object side and a concave image side; a second lens having negative optical power, with a concave object side; a third lens having positive optical power, with a convex object side; a fourth lens; a fifth lens with a convex object side; a sixth lens having positive optical power, with both its object side and image side being convex; a seventh lens having negative optical power; and an eighth lens having positive optical power, with both its object side and image side being convex; wherein the fifth lens and the sixth lens are cemented together to form a doublet lens; the image height H corresponding to the maximum field of view of the optical lens and the entrance pupil diameter ENPD of the optical lens satisfy: 2.7 ≤ H / ENPD ≤ 3.7.

[0005] In one embodiment, the effective focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -3.8≤f1 / f≤-2.0.

[0006] In one embodiment, the effective focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -3.9≤f2 / f≤-2.1.

[0007] In one embodiment, the effective focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 3.0 ≤ f3 / f ≤ 4.1.

[0008] In one embodiment, the effective focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 3.3≤|f4 / f|≤6.0.

[0009] In one embodiment, the effective focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 2.1≤|f5 / f|≤9.2.

[0010] In one embodiment, the effective focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 2.1≤f6 / f≤4.8.

[0011] In one embodiment, the effective focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -6.0≤f7 / f≤-3.3.

[0012] In one embodiment, the effective focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 2.4≤f8 / f≤3.5.

[0013] In one embodiment, the effective focal length fj of the double-lens lens and the effective focal length f of the optical lens satisfy: 2.7≤fj / f≤7.9.

[0014] In one embodiment, the combined focal length Fa of the first lens, the second lens, and the third lens and the combined focal length Fb of the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy: -1.6 ≤ Fa / Fb ≤ -0.6.

[0015] In one embodiment, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 9.1≤TTL / f≤11.4.

[0016] In one embodiment, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5≤BFL / f≤2.2.

[0017] In one embodiment, the image height H corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy the following condition: 2.5 ≤ H / f ≤ 3.5.

[0018] In one embodiment, the maximum aperture Dmax of the optical lens and the total optical length TTL of the optical lens satisfy the following condition: 0.4≤Dmax / TTL≤0.7.

[0019] In one embodiment, the radius of curvature R1 of the object side of the first lens, the radius of curvature R2 of the image side of the first lens, and the effective focal length f of the optical lens satisfy: 5.5≤R1 / f≤14.6, 1.0≤R2 / f≤2.1.

[0020] In one embodiment, the radius of curvature R2 of the image side of the first lens and the radius of curvature R3 of the object side of the second lens satisfy: -3.0≤R3 / R2≤-0.8.

[0021] In one embodiment, the radius of curvature R8 of the object side of the fourth lens and the effective focal length f4 of the fourth lens satisfy: -1.5≤R8 / f4≤5.5.

[0022] In one embodiment, the refractive index Nd and Abbe number Vd of the negative lens in the doublet lens satisfy: 1.8≤Nd≤2.1, 15≤Vd≤40.

[0023] In one embodiment, the center thickness Dt of the double-sided lens and the total optical length TTL of the optical lens satisfy the following condition: 0.1≤Dt / TTL≤0.3.

[0024] The optical lens of this application, through reasonable configuration of the optical power and surface shape of each lens, can achieve confocal focusing of visible and infrared light, enabling the optical lens to obtain clear images even in low-light environments at night. By employing double-sided lenses, clear imaging can be achieved within a temperature range of -40℃ to 80℃ while maintaining a small size and low cost. By controlling the ratio of the image height corresponding to the maximum field of view of the optical lens to the entrance pupil diameter of the optical lens within a reasonable range, the width of the light beam entering the optical lens can be increased, thereby improving the brightness of the optical lens at the imaging plane, avoiding vignetting, facilitating the achievement of large aperture characteristics, providing more incident light to the optical lens, increasing the light transmission of the optical lens, enhancing the imaging effect of the optical lens in dark environments, and simultaneously increasing the field of view of the optical lens, which is conducive to achieving wide-angle characteristics, thereby acquiring more scene information and meeting the wide-angle requirements of the optical lens. Attached Figure Description

[0025] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:

[0026] Figure 1 A schematic diagram of the structure of an optical lens according to Embodiment 1 of this application is shown;

[0027] Figure 2 A schematic diagram of the structure of an optical lens according to Embodiment 2 of this application is shown;

[0028] Figure 3 A schematic diagram of the structure of an optical lens according to Embodiment 3 of this application is shown;

[0029] Figure 4 A schematic diagram of the structure of an optical lens according to Embodiment 4 of this application is shown;

[0030] Figure 5 A schematic diagram of the structure of an optical lens according to Embodiment 5 of this application is shown. Detailed Implementation

[0031] 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 exemplary 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.

[0032] It should be noted that in this specification, the terms "first," "second," 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 optical system discussed below may also be referred to as the second optical system, and the second optical system may also be referred to as the first optical system.

[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 paper, 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.

[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] An exemplary embodiment of this application provides an optical lens, which may include 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 arranged sequentially along the optical axis from the object side to the image side. The first lens may have negative optical power and may be a meniscus lens with a convex object side and a concave image side. The second lens may have negative optical power and its object side may be concave. The third lens may have positive optical power and its object side may be convex. The fifth lens may have a convex object side. The sixth lens may have positive optical power and both its object side and image side may be convex. The seventh lens may have negative optical power. The eighth lens may have positive optical power and both its object side and image side may be convex. The fifth and sixth lenses may be cemented together to form a doublet lens.

[0040] The optical lens of the first aspect of this application, through the rational configuration of the optical power and surface shape of each lens, can achieve confocal focusing of visible and infrared light, enabling the optical lens to obtain clear images even in low-light environments at night. By making the first lens have negative optical power and a meniscus lens with a convex-concave surface, it can collect as much light as possible from a large field of view into the rear lens, increasing the light transmission of the optical lens and helping to fix the direction of large-angle light rays at the edges. By making the second lens have negative optical power and a concave object side, it can further diverge light and adjust the refraction angle of the light, which helps to reduce chromatic aberration of the optical lens. By making the third lens have positive optical power and a convex object side, it can converge light, which helps the light enter the rear lens smoothly and reduces the sensitivity of the optical lens. By rationally configuring the optical power and surface shape of the fourth lens, it can compress the angle of the incident light to achieve a smooth transition of light, allowing the diverging light to enter the rear lens smoothly, further stabilizing the light path and helping to reduce the aperture of the rear lens. By appropriately configuring the optical power of the fifth lens and making its object-side surface convex, excessive divergence of object-side light rays entering the optical lens can be avoided. By giving the sixth lens positive optical power and a biconvex shape, aberrations can be further reduced, image quality improved, and distortion optimized. It also ensures that light rays converge effectively and smoothly at the final point, reaching the image plane smoothly and reducing the overall weight and cost of the optical lens. By giving the seventh lens negative optical power, the light path becomes smoother, facilitating the correction of astigmatism and distortion, thus improving the image quality of the optical lens. By giving the eighth lens positive optical power and a biconvex shape, as much large-angle peripheral light rays as possible can smoothly transition to the rear optical elements, correcting astigmatism and field curvature, and improving the resolving power of the optical lens. By using double-lens film, the air gap between the two lenses can be reduced, thereby reducing the overall optical length; the dispersion of the two lenses can be complementary, which helps to reduce chromatic aberration and improve image quality; the number of assembly parts between the two lenses can be reduced, thereby reducing processes and lowering costs; field curvature can be reduced, thereby correcting off-axis point aberrations of the system; and the focal length can be reasonably allocated, which helps to achieve thermal compensation and obtain good temperature performance; thus, clear imaging can be achieved in a temperature range of -40℃ to 80℃ while taking into account small size and low cost.

[0041] In an exemplary embodiment, the optical lens of this application may further include an aperture stop, which can be set at an appropriate position according to actual needs, for example, the aperture stop may be located between the third lens and the fourth lens. The aperture stop can constrain the light path and control the light intensity.

[0042] In an exemplary embodiment, at least one of the mirror surfaces of the first to eighth lenses can be an aspherical mirror surface. An aspherical lens is characterized by a continuously changing curvature from the lens center to the lens periphery. Unlike a spherical lens, which has a constant curvature from the lens center to the lens periphery, an aspherical lens has better curvature radius characteristics, offering advantages in improving distortion and astigmatism. By using an aspherical lens, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality. In one example, the eighth lens is an aspherical lens with positive optical power. By placing the aspherical lens at the rearmost position of the optical lens, away from the aperture stop, it can better correct the distortion of the optical lens.

[0043] In an exemplary embodiment, the fourth or fifth lens can be made of glass, while any of the remaining lenses from the first to the eighth lens can be made of plastic. Using glass allows the lens to have a high Abbe number and a high refractive index, reducing the size of the lens assembly. Using plastic helps save on the cost of the lens assembly and reduces the manufacturing difficulty of the lens while achieving high image quality. Using a combination of glass and plastic materials can reduce costs while overcoming the problem of focus drift caused by the large coefficient of thermal expansion of aspherical lenses made of plastic in high and low temperature environments, thus meeting the requirements for optical lenses in high and low temperature environments.

[0044] In an exemplary embodiment, the optical lens of this application satisfies the condition 2.7 ≤ H / ENPD ≤ 3.7, where H is the image height corresponding to the maximum field of view of the optical lens, and ENPD is the entrance pupil diameter of the optical lens. By controlling the ratio of the image height corresponding to the maximum field of view of the optical lens to the entrance pupil diameter of the optical lens within a reasonable range, the width of the light beam entering the optical lens can be increased, thereby improving the brightness of the optical lens at the imaging plane, avoiding vignetting, facilitating the achievement of large aperture characteristics, providing more incident light to the optical lens, increasing the light transmission of the optical lens, enhancing the imaging effect of the optical lens in dark environments, and simultaneously increasing the field of view of the optical lens, which is beneficial for achieving wide-angle characteristics, thereby acquiring more scene information and meeting the large-angle requirements of the optical lens.

[0045] In an exemplary embodiment, the optical lens of this application can satisfy the condition -3.8 ≤ f1 / f ≤ -2.0, where f1 is the effective focal length of the first lens and f is the effective focal length of the optical lens. By controlling the ratio of the effective focal length of the first lens to the effective focal length of the optical lens within a reasonable range, the first lens can have an appropriate negative power, which is beneficial for expanding the field of view of the optical lens. At the same time, it can reduce the impact of the distortion generated by the first lens itself on the overall distortion of the optical lens and reduce the difficulty of distortion correction by the rear lens.

[0046] In an exemplary embodiment, the optical lens of this application can satisfy the condition -3.9 ≤ f2 / f ≤ -2.1, where f2 is the effective focal length of the second lens and f is the effective focal length of the optical lens. By controlling the ratio of the effective focal length of the second lens to the effective focal length of the optical lens within a reasonable range, the focal length of the second lens can be reasonably allocated, allowing light to enter the optical lens smoothly. This also helps to collect more light, ensuring the light transmission of the optical lens and improving its resolution.

[0047] In an exemplary embodiment, the optical lens of this application can satisfy the condition 3.0≤f3 / f≤4.1, where f3 is the effective focal length of the third lens and f is the effective focal length of the optical lens. By controlling the ratio of the effective focal length of the third lens to the effective focal length of the optical lens within a reasonable range, the light path between the second and fourth lenses can be controlled, reducing aberrations caused by large-angle light rays entering through the second lens. Simultaneously, the inter-lens structure can be made more compact, which is beneficial for the miniaturization of the optical lens.

[0048] In an exemplary embodiment, the optical lens of this application satisfies the condition 3.3 ≤ |f4 / f| ≤ 6.0, where f4 is the effective focal length of the fourth lens and f is the effective focal length of the optical lens. By controlling the ratio of the effective focal length of the fourth lens to the effective focal length of the optical lens within a reasonable range, the optical power of the fourth lens can be reasonably allocated, allowing light to converge. This enables divergent light to smoothly enter the rear lens and lowers the position of the light entering the rear lens, reducing the aperture of the rear lens and facilitating the miniaturization of the optical lens.

[0049] In an exemplary embodiment, the optical lens of this application can satisfy condition 2.1≤|f5 / f|≤9.2, where f5 is the effective focal length of the fifth lens and f is the effective focal length of the optical lens. By controlling the ratio of the effective focal length of the fifth lens to the effective focal length of the optical lens within a reasonable range, it helps to ensure a smooth transition of light and is beneficial for correcting chromatic aberration in the optical lens.

[0050] In an exemplary embodiment, the optical lens of this application can satisfy the condition 2.1≤f6 / f≤4.8, where f6 is the effective focal length of the sixth lens and f is the effective focal length of the optical lens. By controlling the ratio of the effective focal length of the sixth lens to the effective focal length of the optical lens within a reasonable range, it helps to smooth the transition of light and is beneficial for correcting chromatic aberration in the optical lens.

[0051] In an exemplary embodiment, the optical lens of this application can satisfy the condition -6.0 ≤ f7 / f ≤ -3.3, where f7 is the effective focal length of the seventh lens and f is the effective focal length of the optical lens. By controlling the ratio of the effective focal length of the seventh lens to the effective focal length of the optical lens within a reasonable range, the seventh lens can have negative optical power, which can then be used to balance the astigmatism produced by the subsequent positive lenses.

[0052] In an exemplary embodiment, the optical lens of this application can satisfy the condition 2.4≤f8 / f≤3.5, where f8 is the effective focal length of the eighth lens and f is the effective focal length of the optical lens. By controlling the ratio of the effective focal length of the eighth lens to the effective focal length of the optical lens within a reasonable range, it is beneficial for light to reach the imaging plane smoothly, while reducing the distortion of the optical lens and improving the resolution quality of the optical lens.

[0053] In an exemplary embodiment, the optical lens of this application can satisfy the condition 2.7≤fj / f≤7.9, where fj is the effective focal length of the doublet lens and f is the effective focal length of the optical lens. By controlling the ratio of the effective focal length of the doublet lens to the effective focal length of the optical lens within a reasonable range, it helps to smooth the transition of light, which is beneficial for correcting chromatic aberration, improving image quality, and effectively improving the thermal compensation of the optical lens.

[0054] In an exemplary embodiment, the optical lens of this application can satisfy the condition -1.6 ≤ Fa / Fb ≤ -0.6, where Fa is the combined focal length of the first, second, and third lenses, and Fb is the combined focal length of the fourth, fifth, sixth, seventh, and eighth lenses. By controlling the ratio of the combined focal length of the first, second, and third lenses to the combined focal length of the fourth, fifth, sixth, seventh, and eighth lenses within a reasonable range, the focal length distribution of the lens groups before and after the aperture stop can be made similar, which helps to smoothly transition light and improves the imaging quality of the optical lens.

[0055] In an exemplary embodiment, the optical lens of this application can satisfy the condition 9.1≤TTL / f≤11.4, where TTL is the total optical length of the optical lens and f is the effective focal length of the optical lens. By controlling the ratio of the total optical length to the effective focal length of the optical lens within a reasonable range, the length of the optical lens can be effectively limited, which is beneficial for miniaturizing the optical lens.

[0056] In an exemplary embodiment, the optical lens of this application can satisfy the condition 1.5≤BFL / f≤2.2, where BFL is the back focal length of the optical lens and f is the effective focal length of the optical lens. By controlling the ratio of the back focal length to the effective focal length of the optical lens within a reasonable range, it is beneficial to achieve a balance between obtaining good image quality and an easy-to-assemble optical back focal length, thereby reducing the manufacturing difficulty of optical lens assembly while ensuring the image quality of the optical lens.

[0057] In an exemplary embodiment, the optical lens of this application can satisfy the condition 2.5 ≤ H / f ≤ 3.5, where H is the image height corresponding to the maximum field of view of the optical lens, and f is the effective focal length of the optical lens. By controlling the ratio of the image height corresponding to the maximum field of view of the optical lens to the effective focal length of the optical lens within a reasonable range, it is beneficial to improve the resolving quality of the optical lens.

[0058] In an exemplary embodiment, the optical lens of this application can satisfy the condition 0.4≤Dmax / TTL≤0.7, where Dmax is the maximum aperture of the optical lens and TTL is the total optical length of the optical lens. By controlling the ratio of the maximum aperture to the total optical length of the optical lens within a reasonable range, the aperture at the front end of the optical lens can be made smaller, which is beneficial for miniaturizing the optical lens.

[0059] In an exemplary embodiment, the optical lens of this application satisfies the conditions 5.5≤R1 / f≤14.6 and 1.0≤R2 / f≤2.1, where R1 is the radius of curvature of the object-side surface of the first lens, R2 is the radius of curvature of the image-side surface of the first lens, and f is the effective focal length of the optical lens. By controlling the ratio of the radius of curvature of the object-side surface and the radius of curvature of the image-side surface of the first lens to the effective focal length of the optical lens within a reasonable range, it is beneficial to achieve wide-angle characteristics, thereby enabling the acquisition of more scene information and meeting the requirement of a large field of view for the optical lens.

[0060] In an exemplary embodiment, the optical lens of this application can satisfy the condition -3.0 ≤ R3 / R2 ≤ -0.8, where R2 is the radius of curvature of the image-side surface of the first lens and R3 is the radius of curvature of the object-side surface of the second lens. By controlling the ratio of the radius of curvature of the image-side surface of the first lens to the radius of curvature of the object-side surface of the second lens within a reasonable range, it is beneficial that the incident light rays from the first lens are relatively smooth when they enter the object-side surface of the second lens, thereby reducing the tolerance sensitivity of the optical lens.

[0061] In an exemplary embodiment, the optical lens of this application can satisfy the condition -1.5≤R8 / f4≤5.5, where R8 is the radius of curvature of the object-side surface of the fourth lens, and f4 is the effective focal length of the fourth lens. By controlling the ratio of the radius of curvature of the object-side surface of the fourth lens to the effective focal length of the fourth lens within a reasonable range, the shape of the fourth lens can be reasonably designed and optimized, so that the diverging light rays after passing through the first, second, and third lenses can be further converged, and the aperture of the optical lens can be further reduced.

[0062] In an exemplary embodiment, the fifth and sixth lenses in the optical lens of this application are cemented together to form a doublet lens, or the fourth and fifth lenses are cemented together to form a doublet lens. The optical lens of this application can satisfy the conditions 1.8≤Nd≤2.1, 15≤Vd≤40, where Nd is the refractive index of the negative lens in the doublet lens, and Vd is the Abbe number of the negative lens in the doublet lens. By controlling the refractive index and Abbe number of the negative lens in the doublet lens within a reasonable range, the high and low refractive indices of the lenses in the doublet lens can be matched, which is beneficial for the rapid transition of light in front, increases the aperture, and improves the light transmission, thus helping the optical lens meet the needs of night vision.

[0063] In an exemplary embodiment, the fifth and sixth lenses in the optical lens of this application are cemented together to form a doublet lens, or the fourth and fifth lenses are cemented together to form a doublet lens. The optical lens of this application can satisfy the condition 0.1≤Dt / TTL≤0.3, where Dt is the center thickness of the doublet lens and TTL is the total optical length of the optical lens. By controlling the ratio of the center thickness of the doublet lens to the total optical length of the optical lens within a reasonable range, it is beneficial to reasonably set the center thickness of the doublet lens, which can help improve the relative illumination of the optical lens.

[0064] In an exemplary embodiment, the optical lens of this application may further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface.

[0065] According to the above-described embodiments of the present application, the optical lens can achieve confocal focusing of visible and infrared light by reasonably configuring the optical power and surface shape of each lens, enabling the optical lens to obtain clear images even in low-light environments at night. By using double-sided lenses, clear imaging can be achieved within a temperature range of -40°C to 80°C while maintaining a small size and low cost. By controlling the ratio of the image height corresponding to the maximum field of view of the optical lens to the entrance pupil diameter of the optical lens within a reasonable range, the width of the light beam entering the optical lens can be increased, thereby improving the brightness of the optical lens at the imaging plane, avoiding vignetting, facilitating the achievement of large aperture characteristics, providing more incident light to the optical lens, increasing the light transmission of the optical lens, enhancing the imaging effect of the optical lens in dark environments, and simultaneously increasing the field of view of the optical lens, which is conducive to achieving wide-angle characteristics, thereby acquiring more scene information and meeting the large-angle requirements of the optical lens.

[0066] Those skilled in the art will understand that, without departing from the technical solutions claimed in this application, the number of lenses constituting the optical lens can be changed to obtain the various results and advantages described in this specification.

[0067] Specific embodiments of the optical lens applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0068] Example 1

[0069] The following is for reference Figure 1 Example 1 of the optical lens according to this application is described. Figure 1 A schematic diagram of the structure of an optical lens 110 according to Embodiment 1 of this application is shown.

[0070] like Figure 1 As shown, the optical lens 110 includes, in sequence along the optical axis from the object side to the image side: a first lens L1, a second lens L2, a third lens L3, an aperture stop STO, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter CG, and an imaging plane IMA. The fifth lens L5 and the sixth lens L6 are cemented together to form a doublet lens.

[0071] In this embodiment, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0072] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0073] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0074] The fourth lens L4 has positive optical power, and its object side S8 is convex, while its image side S9 is convex.

[0075] The fifth lens L5 has negative optical power, with its object side S10 being convex and its image side S11 being concave.

[0076] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0077] The seventh lens L7 has negative optical power, with its object side S13 being convex and its image side S14 being concave.

[0078] The eighth lens L8 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0079] Table 1 shows the basic parameters of the optical lens 110 of Embodiment 1, wherein the units for radius of curvature and thickness are millimeters (mm).

[0080]

[0081] Table 1

[0082] In Embodiment 1, the object-side and image-side surfaces of the first lens L1 to the third lens L3, and the seventh lens L7 to the eighth lens L8 are all aspherical, and the surface shape of each aspherical lens is... The following aspherical formulas can be used for limitation:

[0083] (1)

[0084] 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 non-spherical 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 Correction coefficients of order. Table 2 below shows the higher-order coefficients that can be used for the aspherical mirrors S1-S6 and S13-S16 in Example 1. A 4 , A 6 , A 8 , A 10 and A 12 .

[0085]

[0086] Table 2

[0087] Example 2

[0088] The following is for reference Figure 2 Embodiment 2 of the optical lens according to this application is described. In this embodiment, for the sake of brevity, parts similar to those in Embodiment 1 are omitted. Figure 2 A schematic diagram of the structure of an optical lens 120 according to Embodiment 2 of this application is shown.

[0089] like Figure 2 As shown, the optical lens 120 includes, in sequence along the optical axis from the object side to the image side: a first lens L1, a second lens L2, a third lens L3, an aperture stop STO, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter CG, and an imaging plane IMA. The fifth lens L5 and the sixth lens L6 are cemented together to form a doublet lens.

[0090] In this embodiment, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0091] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0092] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0093] The fourth lens L4 has positive optical power, with its object side S8 being concave and its image side S9 being convex.

[0094] The fifth lens L5 has negative optical power, with its object side S10 being convex and its image side S11 being concave.

[0095] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0096] The seventh lens L7 has negative optical power, with its object side S13 being convex and its image side S14 being concave.

[0097] The eighth lens L8 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0098] Table 3 shows the basic parameters of the optical lens 120 in Embodiment 2, where the units for radius of curvature and thickness are millimeters (mm). In this embodiment, the object-side and image-side surfaces of the first lens L1 to the third lens L3, and the seventh lens L7 to the eighth lens L8 are all aspherical. Table 4 shows the higher-order coefficients that can be used for each aspherical mirror surface S1-S6, S13-S16 in Embodiment 2. A 4 , A 6 , A 8 , A 10 and A 12 Each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0099]

[0100] Table 3

[0101]

[0102] Table 4

[0103] Example 3

[0104] The following is for reference Figure 3 Embodiment 3 of the optical lens according to this application is described. In this embodiment, for the sake of brevity, descriptions similar to those in Embodiment 1 are omitted. Figure 3 A schematic diagram of the structure of an optical lens 130 according to Embodiment 3 of this application is shown.

[0105] like Figure 3 As shown, the optical lens 130 includes, in sequence along the optical axis from the object side to the image side: a first lens L1, a second lens L2, a third lens L3, an aperture stop STO, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter CG, and an imaging plane IMA. The fifth lens L5 and the sixth lens L6 are cemented together to form a doublet lens.

[0106] In this embodiment, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0107] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0108] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0109] The fourth lens L4 has positive optical power, with its object side S8 being concave and its image side S9 being convex.

[0110] The fifth lens L5 has negative optical power, with its object side S10 being convex and its image side S11 being concave.

[0111] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0112] The seventh lens L7 has negative optical power, with its object side S13 being convex and its image side S14 being concave.

[0113] The eighth lens L8 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0114] Table 5 shows the basic parameters of the optical lens 130 in Embodiment 3, where the units for radius of curvature and thickness are millimeters (mm). In this embodiment, the object-side and image-side surfaces of the second lens L2 to the third lens L3, and the seventh lens L7 to the eighth lens L8 are all aspherical. Table 6 shows the higher-order coefficients that can be used for each aspherical mirror surface S3-S6 and S13-S16 in Embodiment 3. A 4 , A 6 , A 8 , A 10 and A 12 Each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0115]

[0116] Table 5

[0117]

[0118] Table 6

[0119] Example 4

[0120] The following is for reference Figure 4 Embodiment 4 of the optical lens according to this application is described. In this embodiment, for the sake of brevity, descriptions similar to those in Embodiment 1 are omitted. Figure 4 A schematic diagram of the structure of an optical lens 140 according to Embodiment 4 of this application is shown.

[0121] like Figure 4As shown, the optical lens 140 includes, in sequence along the optical axis from the object side to the image side: a first lens L1, a second lens L2, a third lens L3, an aperture stop STO, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter CG, and an imaging plane IMA. The fifth lens L5 and the sixth lens L6 are cemented together to form a doublet lens.

[0122] In this embodiment, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0123] The second lens L2 has negative optical power, and its object side S3 is concave, as is its image side S4.

[0124] The third lens L3 has positive optical power, with its object side S5 being convex and its image side S6 being concave.

[0125] The fourth lens L4 has positive optical power, with its object side S8 being concave and its image side S9 being convex.

[0126] The fifth lens L5 has negative optical power, with its object side S10 being convex and its image side S11 being concave.

[0127] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0128] The seventh lens L7 has negative optical power, with its object side S13 being concave and its image side S14 being convex.

[0129] The eighth lens L8 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0130] Table 7 shows the basic parameters of the optical lens 140 in Embodiment 4, where the units for radius of curvature and thickness are millimeters (mm). In this embodiment, the object-side and image-side surfaces of the second lens L2 to the fourth lens L4, and the seventh lens L7 to the eighth lens L8 are all aspherical. Table 8 shows the higher-order coefficients that can be used for each aspherical mirror surface S3-S6, S8-S9, and S13-S16 in Embodiment 4. A 4 , A 6 , A 8 , A 10 and A 12 Each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0131]

[0132] Table 7

[0133]

[0134] Table 8

[0135] Example 5

[0136] The following is for reference Figure 5 Embodiment 5 of the optical lens according to this application is described. In this embodiment, for the sake of brevity, parts similar to those in Embodiment 1 are omitted. Figure 5 A schematic diagram of the structure of an optical lens 150 according to Embodiment 5 of this application is shown.

[0137] like Figure 5 As shown, the optical lens 150 includes, in sequence along the optical axis from the object side to the image side: a first lens L1, a second lens L2, a third lens L3, an aperture stop STO, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a filter CG, and an imaging plane IMA. The fifth lens L5 and the sixth lens L6 are cemented together to form a doublet lens.

[0138] In this embodiment, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0139] The second lens L2 has negative optical power, and its object side S3 is concave, as is its image side S4.

[0140] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0141] The fourth lens L4 has positive optical power, and its object side S8 is convex, while its image side S9 is convex.

[0142] The fifth lens L5 has negative optical power, with its object side S10 being convex and its image side S11 being concave.

[0143] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0144] The seventh lens L7 has negative optical power, and its object side S13 is concave, and its image side S14 is concave.

[0145] The eighth lens L8 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0146] Table 9 shows the basic parameters of the optical lens 150 of Embodiment 5, where the units for radius of curvature and thickness are millimeters (mm). In this embodiment, the object-side and image-side surfaces of the first lens L1 to the third lens L3, and the seventh lens L7 to the eighth lens L8 are all aspherical. Table 10 shows the higher-order coefficients that can be used for each aspherical mirror surface S1-S6, S13-S16 in Embodiment 5. A 4 , A 6 , A 8 , A 10 and A 12 Each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0147]

[0148] Table 9

[0149]

[0150] Table 10

[0151] The aperture coefficient FNO, total optical length TTL, and maximum field of view FOV of the optical lenses in Examples 1 to 5 are shown in Table 11.

[0152]

[0153] Table 11

[0154] The conditional expressions of the optical lenses in each of the embodiments in Examples 1 to 5 satisfy the conditions shown in Table 12.

[0155]

[0156] Table 12

[0157] This application also provides an imaging device, whose electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device such as a digital camera, or an imaging module integrated into a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical lens described above.

[0158] 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 protection 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 concept of this application. 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, Along the optical axis from the object side to the image side, the following are included in sequence: The first lens has negative optical power and is a meniscus lens with a convex object side and a concave image side. The second lens has negative optical power and its object side is concave. The third lens has positive optical power and its object side is convex. The fourth lens has positive optical power and its image-side surface is convex. The fifth lens has negative optical power, with a convex object side and a concave image side. The sixth lens has positive optical power, and both its object-side and image-side surfaces are convex. The seventh lens has negative optical power; and The eighth lens has positive optical power, and both its object-side and image-side surfaces are convex. The optical lens has eight lenses with optical power. The fifth lens and the sixth lens are cemented together to form a doublet lens; the image height H corresponding to the maximum field of view of the optical lens and the entrance pupil diameter ENPD of the optical lens satisfy the following: 2.829≤H / ENPD≤3.490; The effective focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy the following: 3.415≤|f4 / f|≤5.

825.

2. The optical lens according to claim 1, characterized in that, The effective focal length f1 of the first lens and the effective focal length f of the optical lens satisfy the following: -3.637≤f1 / f≤-2.

131.

3. The optical lens according to claim 1, characterized in that, The effective focal length f2 of the second lens and the effective focal length f of the optical lens satisfy the following: -3.786≤f2 / f≤-2.

238.

4. The optical lens according to claim 1, characterized in that, The effective focal length f3 of the third lens and the effective focal length f of the optical lens satisfy the following: 3.253≤f3 / f≤3.

954.

5. The optical lens according to claim 1, characterized in that, The effective focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy the following: 3.168≤|f5 / f|≤9.

104.

6. The optical lens according to claim 1, characterized in that, The effective focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy the following: 2.216≤f6 / f≤3.

556.

7. The optical lens according to claim 1, characterized in that, The effective focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy the following: -5.870≤f7 / f≤-3.

580.

8. The optical lens according to claim 1, characterized in that, The effective focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy the following: 2.589≤f8 / f≤3.

293.

9. The optical lens according to claim 1, characterized in that, The effective focal length fj of the double-sided lens and the effective focal length f of the optical lens satisfy the following: 2.870≤fj / f≤7.

806.

10. The optical lens according to claim 9, characterized in that, The combined focal length Fa of the first lens, the second lens, and the third lens, and the combined focal length Fb of the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens satisfy the following: -1.485≤Fa / Fb≤-0.

791.

11. The optical lens according to claim 1, characterized in that, The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy the following: 9.239≤TTL / f≤10.

951.

12. The optical lens according to claim 1, characterized in that, The back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy the following: 1.687≤BFL / f≤2.

009.

13. The optical lens according to claim 1, characterized in that, The image height H corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy the following: 2.608≤H / f≤3.

234.

14. The optical lens according to claim 1, characterized in that, The maximum aperture Dmax of the optical lens and the total optical length TTL of the optical lens satisfy the following: 0.476≤Dmax / TTL≤0.

584.

15. The optical lens according to claim 1, characterized in that, 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 effective focal length f of the optical lens satisfy the following: 5.5≤R1 / f≤10.918, 1.0≤R2 / f≤2.

029.

16. The optical lens according to claim 1, characterized in that, The radius of curvature R2 of the image-side surface of the first lens and the radius of curvature R3 of the object-side surface of the second lens satisfy the following: -2.894≤R3 / R2≤-0.

948.

17. The optical lens according to claim 1, characterized in that, The radius of curvature R8 of the object-side surface of the fourth lens and the effective focal length f4 of the fourth lens satisfy the following: -1.397≤R8 / f4≤5.

411.

18. The optical lens according to claim 1, characterized in that, The refractive index Nd and Abbe number Vd of the negative lens in the doublet lens satisfy the following: 1.85≤Nd≤1.92, 18.9≤Vd≤31.

4.

19. The optical lens according to claim 1, characterized in that, in, The center thickness Dt of the double-sided lens and the total optical length TTL of the optical lens satisfy the following: 0.1≤Dt / TTL≤0.176.

Images