A fixed focus lens

Abstract

The application discloses a fixed-focus lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens and an eleventh lens arranged in sequence along an optical axis from an object plane to an image plane; the first lens, the second lens, the third lens, the fifth lens, the eighth lens and the eleventh lens are negative-power lenses; the fourth lens, the sixth lens, the seventh lens, the ninth lens and the tenth lens are positive-power lenses; the third lens comprises a third object-side surface close to the object plane and a third image-side surface close to the image plane, the third object-side surface is a concave surface, and the third image-side surface is a convex surface; and the fourth lens comprises a fourth object-side surface close to the object plane, and the fourth object-side surface is a convex surface. The above technical scheme can realize at least one beneficial effect, such as excellent imaging, large light incidence, large target surface, wide angle and the like.

Description

Technical Field

[0001] The present invention relates to the field of optical device technology, and in particular to a fixed-focus lens. Background Technology

[0002] In today's rapidly evolving technological era, the application scenarios for security cameras are constantly expanding and extending, thus further increasing the need and requirements for security cameras.

[0003] Currently, most security cameras use large apertures, but it is difficult to achieve high image quality at the same time. Summary of the Invention

[0004] This invention provides a fixed-focus lens that achieves a lens design that balances large aperture and high resolution.

[0005] This invention provides a fixed-focus lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged sequentially along the optical axis from the object plane to the image plane;

[0006] The first lens, the second lens, the third lens, the fifth lens, the eighth lens, and the eleventh lens are all negative power lenses, while the fourth lens, the sixth lens, the seventh lens, the ninth lens, and the tenth lens are all positive power lenses.

[0007] The third lens includes a third object-side surface near the object plane and a third image-side surface near the image plane. The third object-side surface is concave, and the third image-side surface is convex.

[0008] The fourth lens includes a fourth object-side surface near the object surface, and the fourth object-side surface is convex.

[0009] Optionally, the optical power of the first lens is φ1, the optical power of the second lens is φ2, the combined optical power of the third and fourth lenses is φ34, the optical power of the fifth lens is φ5, the optical power of the sixth lens is φ6, the optical power of the seventh lens is φ7, the optical power of the eighth lens is φ8, the optical power of the ninth lens is φ9, the optical power of the tenth lens is φ10, and the optical power of the eleventh lens is φ11.

[0010] Where -0.67≤φ1 / φ≤-0.33, -0.18≤φ2 / φ≤-0.02, 0.07≤φ34 / φ≤0.24,

[0011] 0.05≤(φ5+φ6) / φ≤0.25, 0.06≤φ7 / φ≤0.38, -0.30≤φ8 / φ≤-0.01,

[0012] 0.07≤φ9 / φ≤0.41, 0.06≤φ10 / φ≤0.26; -0.16≤φ11 / φ≤-0.01.

[0013] Optionally, the aperture of the first lens is DT1, and the center thickness of the first lens is CT1;

[0014] Among them, 3.03≤DT1 / CT1≤10.87.

[0015] Optionally, the first lens includes a first object-side surface near the object surface and a first image-side surface near the image surface, wherein the first object-side surface is convex and the first image-side surface is concave.

[0016] The second lens includes a second image-side surface near the image plane, and the second image-side surface is concave.

[0017] The fifth lens includes a fifth object-side surface near the object plane and a fifth image-side surface near the image plane. The fifth object-side surface is concave, and the fifth image-side surface is convex.

[0018] The sixth lens includes a sixth object-side surface near the object plane and a sixth image-side surface near the image plane. The sixth object-side surface is convex, and the sixth image-side surface is convex.

[0019] The seventh lens includes a seventh object-side surface near the object plane and a seventh image-side surface near the image plane. The seventh object-side surface is convex, and the seventh image-side surface is convex.

[0020] The eighth lens includes an eighth object-side surface near the object plane and an eighth image-side surface near the image plane. The eighth object-side surface is concave, and the eighth image-side surface is concave.

[0021] The ninth lens includes a ninth object-side surface near the object plane and a ninth image-side surface near the image plane. The ninth object-side surface is convex, and the ninth image-side surface is convex.

[0022] The tenth lens includes a tenth image side surface near the image plane, and the tenth image side surface is convex.

[0023] The eleventh lens includes an eleventh object-side surface near the object plane and an eleventh image-side surface near the image plane. The eleventh object-side surface is concave, and the eleventh image-side surface is convex.

[0024] Optionally, the seventh lens and the eighth lens are cemented together;

[0025] Alternatively, the eighth lens and the ninth lens are cemented together.

[0026] Alternatively, the seventh lens, the eighth lens, and the ninth lens may be cemented together.

[0027] Optionally, the first lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all glass spherical lenses;

[0028] The second lens, the third lens, the fourth lens, the fifth lens, the tenth lens, and the eleventh lens are all plastic aspherical lenses.

[0029] Optionally, the seventh lens has a refractive index of Nd7 and an Abbe number of Vd7; the eighth lens has a refractive index of Nd8 and an Abbe number of Vd8; and the ninth lens has a refractive index of Nd9 and an Abbe number of Vd9.

[0030] Among them, 4.78≤Nd7+Nd8+Nd9≤4.90, 57.70≤Vd7≤73.30, 25.22≤Vd8≤34.64, and 57.70≤Vd9≤73.30.

[0031] Optionally, the maximum image height of the fixed-focus lens is IH, and the entrance pupil diameter of the fixed-focus lens is EPD;

[0032] Among them, 2.60≤IH / EPD≤2.79.

[0033] Optionally, the fixed-focus lens has an aperture of F#, an imaging field of view of FOV, and a total optical length of TTL;

[0034] Among them, F#≤1.1, FOV≥160°, TTL≤40mm.

[0035] Optionally, the fixed-focus lens further includes an aperture stop and a filter, wherein the aperture stop is disposed in the optical path between the third lens and the fourth lens;

[0036] The filter is disposed in the optical path between the eleventh lens and the image plane.

[0037] The fixed-focus lens provided in this embodiment of the invention includes eleven lenses with optical power. By reasonably setting the number of lenses, the total length of the fixed-focus lens can be ensured to be appropriate, achieving a relatively small-scale design while maintaining small imaging aberrations and high image quality. Furthermore, the optical power of the eleven lenses is arranged in a negative-negative-negative-positive-positive-positive-negative-positive-positive-negative pattern. This reasonable arrangement of the optical power of the eleven lenses increases the aperture of the optical lens and improves its imaging resolution. Additionally, the object-side surface of the third lens is concave, and the image-side surface is convex, while the object-side surface of the fourth lens is convex. By reasonably designing the surface shapes of the third and fourth lenses, the divergence and convergence of light entering the optical system can be effectively controlled, further achieving a large aperture.

[0038] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of a fixed-focus lens provided in Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the spherical aberration curve of a fixed-focus lens provided in Embodiment 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the structure of a fixed-focus lens provided in Embodiment 2 of the present invention;

[0043] Figure 4 This is a schematic diagram of the spherical aberration curve of a fixed-focus lens provided in Embodiment 2 of the present invention;

[0044] Figure 5 This is a schematic diagram of the structure of a fixed-focus lens provided in Embodiment 3 of the present invention;

[0045] Figure 6 This is a schematic diagram of the spherical aberration curve of a fixed-focus lens provided in Embodiment 3 of the present invention;

[0046] Figure 7 This is a schematic diagram of the structure of a fixed-focus lens provided in Embodiment 4 of the present invention;

[0047] Figure 8This is a schematic diagram of the spherical aberration curve of a fixed-focus lens provided in Embodiment 4 of the present invention. Detailed Implementation

[0048] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0049] Example 1

[0050] Figure 1 This is a schematic diagram of the structure of a fixed-focus lens provided in Embodiment 1 of the present invention, as shown below. Figure 1 As shown, the fixed-focus lens provided in this embodiment of the invention includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, an eighth lens 108, a ninth lens 109, a tenth lens 110, and an eleventh lens 111 arranged sequentially along the optical axis from the object plane to the image plane. The first lens 101, the second lens 102, the third lens 103, the fifth lens 105, the eighth lens 108, and the eleventh lens 111 are all negative power lenses, while the fourth lens 104, the sixth lens 106, the seventh lens 107, the ninth lens 109, and the tenth lens 110 are all positive power lenses. The third lens 103 includes a third object-side surface near the object plane and a third image-side surface near the image plane. The third object-side surface is concave, and the third image-side surface is convex. The fourth lens 104 includes a fourth object-side surface near the object plane. The fourth object-side surface is convex.

[0051] like Figure 1 As shown, the fixed-focus lens provided in this embodiment of the invention includes eleven lenses with optical power. The arrangement of eleven lenses with optical power ensures that the number of lenses in the fixed-focus lens is reasonable. Too many lenses will result in a large lens size, and too few lenses will result in a large aberration due to a single lens bearing a large optical power. This ensures that the fixed-focus lens is miniaturized while ensuring small imaging aberrations and high imaging quality.

[0052] Furthermore, optical power is equal to the difference between the convergence of the beam at the image plane and the convergence of the beam at the object plane, characterizing the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger the bending ability of light; the smaller the absolute value, the weaker the bending ability. When the optical power is positive, the refraction of light is converging; when the optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., a surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group). In this embodiment of the invention, the optical powers of the first lens 101, the second lens 102, and the third lens 103 are all negative. As the lenses that first adjust the incident light in the optical lens, their negative optical power ensures that the light has a larger aperture before entering the aperture stop, increasing the aperture of the optical lens and enabling the lens to still produce clear images under dim or dark conditions. The fourth lens 104, with its positive optical power, can promptly correct the large aberrations produced by the first lens 101, the second lens 102, and the third lens 103, especially effectively correcting edge aberrations of the optical lens, thereby improving the imaging resolution of the optical system. Furthermore, the fifth lens group 105 has a negative optical power, the sixth lens 106 has a positive optical power, the seventh lens 107 has a positive optical power, the eighth lens 108 has a negative optical power, the ninth lens 109 has a positive optical power, the tenth lens 110 has a positive optical power, and the eleventh lens 111 has a negative optical power. Since the optical power of each subsequent lens in the optical path differs from that of the preceding lens, this facilitates aberration correction.

[0053] Furthermore, the object-side surface of a lens can be understood as the surface of the lens closest to the object plane, and the image-side surface of a lens can be understood as the surface of the lens closest to the image plane. In this embodiment of the invention, the object-side surface of the third lens 103 is concave, and the image-side surface is convex. This can be understood as the object-side surface of the third lens 103 being concave towards the object plane near the optical axis, and the image-side surface being convex towards the image plane near the optical axis; that is, the third lens 103 is a lens with a concave-convex structure. The object-side surface of the fourth lens 104 is convex, and the image-side surface is either convex or concave. This can be understood as the object-side surface of the fourth lens 104 being convex towards the object plane near the optical axis, and the image-side surface being either convex or concave towards the image plane near the optical axis; that is, the third lens 103 is a biconvex structure or a convex-concave lens. By designing the third lens 103 as a negative lens with a concave-convex structure and the fourth lens 104 as a positive lens with a convex-concave structure or a biconvex structure, the surface shape and optical power of the third lens 103 and the fourth lens 104 can be matched to effectively control the light propagating in the optical lens to first diverge and then converge, which is beneficial to achieving a large aperture.

[0054] In summary, the fixed-focus lens provided in this embodiment of the invention includes eleven lenses with optical power. By reasonably setting the number of lenses, the total length of the fixed-focus lens can be ensured to be appropriate, achieving a relatively miniaturized design while ensuring small imaging aberrations and high image quality. Furthermore, the optical power of the eleven lenses is arranged in a negative-negative-negative-positive-positive-positive-negative-positive-positive-negative pattern. This reasonable arrangement of the optical power of the eleven lenses can increase the aperture of the optical lens and improve its imaging resolution. Moreover, the object-side surface of the third lens is concave, and the image-side surface is convex, while the object-side surface of the fourth lens is convex. By reasonably designing the surface shapes of the third and fourth lenses, the divergence and convergence of light entering the optical system can be effectively controlled, further achieving a large aperture.

[0055] Based on the above embodiments, continue to refer to Figure 1 As shown, the fixed-focus lens in this embodiment of the invention may also include an aperture stop STO and a filter 112. The aperture stop STO is disposed in the optical path between the third lens 103 and the fourth lens 104, and the filter 112 is disposed in the optical path between the eleventh lens 111 and the image plane.

[0056] Specifically, setting the STO (Side Stop) can adjust the direction of light propagation, which helps improve image quality. Furthermore, in this fixed-focus lens, the STO, set within the optical system, can limit the beam size and control the amount of light passing through the lens, thus allowing for a smaller aperture value and achieving a large aperture. The filter 112 can filter out stray light, improving image quality.

[0057] Furthermore, the optical lens provided in this embodiment of the invention may also include a protective glass and an imaging sensor. The protective glass may be disposed on the image-side of the filter, and the imaging sensor may be disposed on the image-side of the protective glass. The optical system is protected by the protective glass, and the image is acquired by the imaging sensor, thus enabling the optical system to perform its normal imaging function.

[0058] Based on the above embodiments, the optical power of the first lens 101 is φ1, the optical power of the second lens 102 is φ2, the combined optical power of the third lens 103 and the fourth lens 104 is φ34, the optical power of the fifth lens 105 is φ5, the optical power of the sixth lens 106 is φ6, the optical power of the seventh lens 107 is φ7, the optical power of the eighth lens 108 is φ8, the optical power of the ninth lens 109 is φ9, the optical power of the tenth lens 110 is φ10, and the optical power of the eleventh lens 1... The optical power of 11 is φ11; where -0.67≤φ1 / φ≤-0.33, -0.18≤φ2 / φ≤-0.02, 0.07≤φ34 / φ≤0.24, 0.05≤(φ5+φ6) / φ≤0.25, 0.06≤φ7 / φ≤0.38, -0.30≤φ8 / φ≤-0.01, 0.07≤φ9 / φ≤0.41, 0.06≤φ10 / φ≤0.26; -0.16≤φ11 / φ≤-0.01.

[0059] Specifically, setting the optical power of the first lens 101 to -0.67≤φ1 / φ≤-0.33 ensures that the system can pass light rays at large angles and control the incident angle of the optical system. Setting the optical power of the second lens 102 to -0.18≤φ2 / φ≤-0.02, and the optical power of the third lens 103 and the fourth lens 104 to 0.07≤φ34 / φ≤0.24, can correct off-axis aberrations, optimize field curvature, and adjust the focal length. Setting the optical power of the fifth lens 105 and the sixth lens 106 to 0.05≤(φ5+φ6) / φ≤0.25 can better balance the lens resolution, thereby improving the image quality of the lens. Setting the optical power of the seventh lens 107 to meet 0.06≤φ7 / φ≤0.38, the eighth lens 108 to meet -0.30≤φ8 / φ≤-0.01, and the ninth lens 109 to meet 0.07≤φ9 / φ≤0.41 can eliminate chromatic aberration and reduce assembly difficulty. Setting the optical power of the tenth lens 110 to meet 0.06≤φ10 / φ≤0.26 and the eleventh lens 111 to meet -0.16≤φ11 / φ≤-0.01 is beneficial for correcting spherical aberration and chromatic aberration of the optical lens, further improving image quality; it also avoids excessive pressure on the other lenses during the correction of chromatic aberration, aberrations, and CRA, which could result in shapes that are difficult to process.

[0060] Based on the above embodiments, the aperture of the first lens 101 is DT1, and the center thickness of the first lens 101 is CT1; wherein, 3.03≤DT1 / CT1≤10.87. As the first lens in the optical lens to adjust the incident light, setting the correspondence between the aperture and center thickness of the first lens 101 can further ensure that the optical lens can pass large-angle light, control the incident angle of the optical lens, and ensure the amount of light entering the optical lens.

[0061] Based on the above embodiments, the first lens 101 includes a first object-side surface near the object plane and a first image-side surface near the image plane, the first object-side surface being convex and the first image-side surface being concave; the second lens 102 includes a second image-side surface near the image plane, the second image-side surface being concave; the fifth lens 105 includes a fifth object-side surface near the object plane and a fifth image-side surface near the image plane, the fifth object-side surface being concave and the fifth image-side surface being convex; the sixth lens 106 includes a sixth object-side surface near the object plane and a sixth image-side surface near the image plane, the sixth object-side surface being convex and the sixth image-side surface being convex; the seventh lens 107 includes a seventh object-side surface near the object plane and a fifth image-side surface near the image plane. The seventh image side surface near the image plane is convex, and the seventh object side surface is convex; the eighth lens 108 includes an eighth object side surface near the object plane and an eighth image side surface near the image plane, the eighth object side surface is concave, and the eighth image side surface is concave; the ninth lens 109 includes a ninth object side surface near the object plane and a ninth image side surface near the image plane, the ninth object side surface is convex, and the ninth image side surface is convex; the tenth lens 110 includes a tenth image side surface near the image plane, the tenth image side surface is convex; the eleventh lens 111 includes an eleventh object side surface near the object plane and an eleventh image side surface near the image plane, the eleventh object side surface is concave, and the eleventh image side surface is convex.

[0062] The object-side surface of the first lens 101 is convex, and the image-side surface is concave. This can be understood as the object-side surface of the first lens 101 convex towards the object plane near the optical axis, while the image-side surface is concave towards the image plane near the optical axis. In other words, the first lens 101 is a meniscus lens with a convex-concave structure. Designing the object-side surface of the first lens as convex helps to converge light rays into the system as much as possible, while designing the image-side surface as concave allows light rays to enter the system at a smaller deflection angle, which is beneficial for achieving a larger aperture and smaller aberrations.

[0063] The object-side surface of the second lens 102 can be convex or concave, and the image-side surface is concave. This can be understood as the object-side surface of the second lens 102 being convex or concave towards the object surface near the optical axis, and the image-side surface being concave towards the image surface near the optical axis. In other words, the second lens 102 is a lens with a convex-concave structure or a double-concave structure.

[0064] The object side of the fifth lens 105 is concave, and the image side is convex. This can be understood as the object side of the fifth lens 105 being concave towards the object surface near the optical axis, and the image side being convex towards the image surface near the optical axis. In other words, the fifth lens 105 is a lens with a concave-convex structure.

[0065] The object-side surface of the sixth lens 106 is convex, and the image-side surface is also convex. This can be understood as the object-side surface of the sixth lens 106 convex towards the object plane near the optical axis, and the image-side surface convex towards the image plane near the optical axis. In other words, the sixth lens 106 can be considered a biconvex lens. Since both surfaces of the sixth lens 106 are convex, it can effectively control the direction of light rays, allowing the light to enter the seventh lens 107 with a smaller deflection angle, thus effectively reducing the system's tolerance sensitivity.

[0066] The seventh lens 107 has a convex object-side surface and a convex image-side surface. This can be understood as the object-side surface of the seventh lens 107 bulging towards the object plane near the optical axis, and the image-side surface bulging towards the image plane near the optical axis. Therefore, the seventh lens 107 is a biconvex lens. The eighth lens 108 has a concave object-side surface and a concave image-side surface. This can be understood as the object-side surface of the eighth lens 108 being concave towards the object plane near the optical axis, and the image-side surface being concave towards the image plane near the optical axis. Therefore, the eighth lens 108 is a biconcave lens. The ninth lens 109 has a convex object-side surface and a convex image-side surface. This can be understood as the object-side surface of the ninth lens 109 bulging towards the object plane near the optical axis, and the image-side surface bulging towards the image plane near the optical axis. Therefore, the ninth lens 109 is a biconvex lens. By appropriately setting the surface shapes of the seventh lens 107, the eighth lens 108, and the ninth lens 109, it is possible to ensure a smaller distance between the seventh lens 107 and the eighth lens 108, and a smaller distance between the eighth lens 108 and the ninth lens 109. This is beneficial for miniaturizing the optical lens and designing its overall length. Furthermore, appropriately setting the surface shapes of the seventh lens 107, the eighth lens 108, and the ninth lens 109 can also meet the bonding requirements between them.

[0067] The object-side surface of the tenth lens 110 can be convex or concave, and the image-side surface is convex. This can be understood as the object-side surface of the tenth lens 110 being convex or concave towards the object surface near the optical axis, and the image-side surface being convex towards the image surface near the optical axis. In other words, the tenth lens 110 is a lens with a biconvex structure or a concave-convex structure.

[0068] The object-side surface of the eleventh lens 111 is concave, and the image-side surface is convex. This can be understood as the object-side surface of the eleventh lens 111 being concave towards the object surface near the optical axis, and the image-side surface being convex towards the image surface near the optical axis. In other words, the eleventh lens 111 is a lens with a concave-convex structure.

[0069] By properly setting the concave and convex surfaces of each lens, it is possible to ensure that each lens modulates the light emission angle and reduce the spacing between adjacent lenses, which is beneficial for achieving a small-volume fixed-focus lens design.

[0070] Based on the above embodiments, the seventh lens 107 and the eighth lens 108 are cemented together; or, the eighth lens 108 and the ninth lens 109 are cemented together; or, the seventh lens 107, the eighth lens 108 and the ninth lens 109 are cemented together.

[0071] Specifically, the cemented configuration of different lenses can be understood as the image-side surface of the preceding lens and the object-side surface of the following lens being bonded together in the optical path, possessing the same surface shape. In this embodiment of the invention, the seventh lens 107 and the eighth lens 108 are cemented together, as shown below. Figure 1 As shown; or, the eighth lens 108 and the ninth lens 109 are cemented together; or, the seventh lens 107, the eighth lens 108, and the ninth lens 109 are cemented together. The cementing of the seventh lens 107 and the eighth lens 108 can be understood as the image-side of the seventh lens 107 and the object-side of the eighth lens 108 being bonded together to form a two-bonded lens; the cementing of the eighth lens 108 and the ninth lens 109 can be understood as the image-side of the eighth lens 108 and the object-side of the ninth lens 109 being bonded together to form a two-bonded lens; the cementing of the seventh lens 107, the eighth lens 108, and the ninth lens 109 can be understood as the image-side of the seventh lens 107 being bonded to the object-side of the eighth lens 108, and the image-side of the eighth lens 108 being bonded to the object-side of the ninth lens 109, forming a three-bonded lens. Cemented lenses can be used to minimize or eliminate chromatic aberration. Using cemented lenses in optical lenses can improve image quality, reduce light energy reflection loss, and thus improve the sharpness of the lens image. Furthermore, the cementation of the lenses eliminates the air gap between the two lenses, making the overall optical lens compact and meeting the requirements for system miniaturization. In addition, the cementation of the lenses reduces tolerance sensitivity issues such as tilting / eccentricity that may occur during the assembly of the lens units.

[0072] Furthermore, the two or three lenses that are glued together can be supported by a gasket or glued together. The specific method of gluing is not limited in the embodiments of the present invention.

[0073] Based on the above embodiments, the first lens 101, the sixth lens 106, the seventh lens 107, the eighth lens 108 and the ninth lens 109 are all glass spherical lenses; the second lens 102, the third lens 103, the fourth lens 104, the fifth lens 105, the tenth lens 110 and the eleventh lens 111 are all plastic aspherical lenses.

[0074] Specifically, aspherical lenses are characterized by a continuous change in curvature from the center to the periphery, unlike spherical lenses which have a constant curvature from the center to the periphery. Aspherical lenses have better curvature radius characteristics, which improves distortion aberrations and astigmatism. The second lens 102, third lens 103, fourth lens 104, fifth lens 105, tenth lens 110, and eleventh lens 111 are all plastic aspherical lenses. The use of plastic aspherical lenses helps to reduce the processing complexity of aspherical lenses, and the lower cost of aspherical lenses can reduce the cost of the optical system.

[0075] Spherical lenses are characterized by a constant curvature from the center to the periphery, ensuring a simple lens setup. Furthermore, due to the low coefficient of thermal expansion and good stability of glass lenses, the first lens 101, sixth lens 106, seventh lens 107, eighth lens 108, and ninth lens 109 are all glass spherical lenses. The thermal properties of glass spherical lenses are more stable, ensuring good resolving power over a wide temperature range when handling higher optical powers. Moreover, the wider range of glass materials available allows for more flexible selection of refractive index and Abbe number, enabling better control over higher aberrations and chromatic aberrations, meeting the needs of use under complex conditions.

[0076] Therefore, the fixed-focus lens provided in this embodiment of the invention can adopt a combination of glass spherical lenses and plastic aspherical lenses, which can effectively control the cost of the fixed-focus lens while ensuring its optical performance; at the same time, the lens materials have a mutual compensating effect, which can ensure normal use in high and low temperature environments.

[0077] Based on the above embodiments, the refractive index of the seventh lens 107 is Nd7 and the Abbe number is Vd7; the refractive index of the eighth lens 108 is Nd8 and the Abbe number is Vd8; and the refractive index of the ninth lens 109 is Nd9 and the Abbe number is Vd9. Wherein, 4.78≤Nd7+Nd8+Nd9≤4.90, 57.70≤Vd7≤73.30, 25.22≤Vd8≤34.64, and 57.70≤Vd9≤73.30. When the seventh lens 107, the eighth lens 108, and the ninth lens 109 are within this range, chromatic aberration of the optical lens can be guaranteed, thereby achieving high image quality.

[0078] Based on the above embodiments, the maximum image height of the fixed-focus lens is IH, and the entrance pupil diameter of the fixed-focus lens is EPD; wherein, 2.60≤IH / EPD≤2.79. Satisfying the above relationship allows the entrance pupil diameter of the optical lens to be controlled while meeting the requirements of large target area and high-quality imaging, ensuring sufficient edge field of view of the large target area imaging system and improving image brightness.

[0079] Based on the above embodiments, the fixed-focus lens has an aperture of F#, an imaging field of view of FOV, and a total optical length of TTL; wherein, F#≤1.1, FOV≥160°, and TTL≤40mm. This achieves a fixed-focus lens with a large aperture, a large field of view, and a small total optical length.

[0080] As a feasible implementation method, the parameters of each lens in the fixed-focus lens will be explained next.

[0081] Table 1. Optical design values ​​for a fixed-focus lens in Example 1

[0082]

[0083] Table 2 Design values ​​of optical physical parameters for fixed-focus lenses

[0084]

[0085] The surface numbers in Table 2 are assigned according to the surface sequence of each lens. "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on. "STO" represents the aperture stop of the lens. "IMA" represents the image plane of the lens. The radius of curvature represents the curvature of the lens surface; a positive value indicates the surface bends towards the image plane, and a negative value indicates the surface bends towards the object plane. "Infinity" indicates the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index Nd represents the ability of the material between the current and next surfaces to deflect light; a blank space indicates the current location is air with a refractive index of 1. The Abbe number Vd represents the dispersion characteristics of the material between the current and next surfaces; a blank space indicates the current location is air. The semi-diameter represents the effective diameter of the lens. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0086] In this embodiment of the invention, the aspherical lens of the fixed-focus lens satisfies the following formula:

[0087]

[0088] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; and the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the AG aspherical polynomial.

[0089] Table 3 Aspherical coefficients of fixed-focus lenses

[0090]

[0091] Wherein, 1.452713E-03 represents 1.452713 × 10 -3 All other parameters can be represented in this way.

[0092] This embodiment satisfies the following parameters:

[0093] Focal length: f=3.62mm;

[0094] Aperture number: F#=1.08;

[0095] The field of view (FOV) corresponding to the φ9.1mm imaging target surface is 160°.

[0096] Total optical length: TTL=36.62mm.

[0097] Figure 2 This is a schematic diagram of the spherical aberration curve of a fixed-focus lens provided in Embodiment 1 of the present invention. The vertical direction represents the normalized aperture, 0 indicates that it is on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (436nm, 486nm, 546nm, 588nm, and 656nm, respectively), which are... Figure 2 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of this fixed-focus lens is well controlled at each wavelength, which can meet the requirements of wide-spectrum applications.

[0098] In summary, the fixed-focus lens provided in this embodiment of the invention adopts a 5G6P structure, with its optical power matching in the form of negative-negative-negative-positive-positive-positive-negative-positive-positive-negative. The optical power, shape, and position of each lens are reasonably arranged, achieving a focal length of approximately 3.62mm. This results in clear imaging with a larger aperture (F1.08) on a target surface larger than φ9.1mm. It can be matched with a 1 / 1.8-inch four-megapixel chip to meet high image quality requirements, and the field of view reaches 160°, making it suitable for a wider range of usage needs.

[0099] Example 2

[0100] Figure 3 This is a schematic diagram of the structure of a fixed-focus lens provided in Embodiment 2 of the present invention, as shown below. Figure 3As shown, the fixed-focus lens provided in Embodiment 2 of the present invention includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, an eighth lens 108, a ninth lens 109, a tenth lens 110, and an eleventh lens 111 arranged sequentially along the optical axis from the object plane to the image plane; the first lens 101, the second lens 102, the third lens 103, the fifth lens 105, the eighth lens 108, and the eleventh lens 111 are all negative power lenses, and the fourth lens 104, the sixth lens 106, the seventh lens 107, the ninth lens 109, and the tenth lens 110 are all positive power lenses; the third lens 103 includes a third object-side surface near the object plane and a third image-side surface near the image plane, the third object-side surface being concave and the third image-side surface being convex; the fourth lens 104 includes a fourth object-side surface near the object plane, the fourth object-side surface being convex.

[0101] Other parameters are the same as in Example 1, and will not be repeated here.

[0102] As another feasible implementation method, the specific parameters of the fixed-focus lens are explained below.

[0103] Table 4. Optical design values ​​for a fixed-focus lens in Example 2.

[0104]

[0105] Table 5 Design values ​​of optical physical parameters for fixed-focus lenses

[0106]

[0107] The surface numbers in Table 5 are assigned according to the surface sequence of each lens. "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on. "STO" represents the aperture stop of the lens. "IMA" represents the image plane of the lens. The radius of curvature represents the curvature of the lens surface; a positive value indicates the surface bends towards the image plane, and a negative value indicates the surface bends towards the object plane. "Infinity" indicates the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index Nd represents the ability of the material between the current and next surfaces to deflect light; a blank space indicates the current location is air with a refractive index of 1. The Abbe number Vd represents the dispersion characteristics of the material between the current and next surfaces; a blank space indicates the current location is air. The semi-diameter represents the effective diameter of the lens. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0108] In this embodiment of the invention, the aspherical lens of the fixed-focus lens satisfies the following formula:

[0109]

[0110] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; and the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the AG aspherical polynomial.

[0111] Table 6 Aspherical coefficients of fixed-focus lenses

[0112]

[0113] Where 1.008381E-03 represents 1.008381 × 10 -3 All other parameters can be represented in this way.

[0114] This embodiment satisfies the following parameters:

[0115] Focal length: f=3.59mm;

[0116] Aperture number: F#=1.08;

[0117] The field of view (FOV) corresponding to the φ9.1mm imaging target surface is 160°.

[0118] Total optical length: TTL=36.82mm.

[0119] Figure 4 This is a schematic diagram of the spherical aberration curve of a fixed-focus lens provided in Embodiment 2 of the present invention. The vertical direction represents the normalized aperture, 0 indicates that it is on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (436nm, 486nm, 546nm, 588nm, and 656nm, respectively), which are... Figure 4 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of this fixed-focus lens is well controlled at each wavelength, which can meet the requirements of wide-spectrum applications.

[0120] In summary, the fixed-focus lens provided in this embodiment of the invention adopts a 5G6P structure, with its optical power matching pattern being negative-negative-negative-positive-positive-positive-negative-positive-positive-negative. The optical power, shape, and position layout of each lens are reasonable, achieving a focal length of approximately 3.59mm. This results in clear imaging with a larger aperture (F1.08) on a target surface larger than φ9.1mm. It can be matched with a 1 / 1.8-inch four-megapixel chip to meet high image quality requirements, and the field of view reaches 160°, making it suitable for a wider range of usage needs.

[0121] Example 3

[0122] Figure 5 This is a schematic diagram of the structure of a fixed-focus lens provided in Embodiment 3 of the present invention, as shown below. Figure 5 As shown, the fixed-focus lens provided in Embodiment 3 of the present invention includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, an eighth lens 108, a ninth lens 109, a tenth lens 110, and an eleventh lens 111 arranged sequentially along the optical axis from the object plane to the image plane; the first lens 101, the second lens 102, the third lens 103, the fifth lens 105, the eighth lens 108, and the eleventh lens 111 are all negative power lenses, and the fourth lens 104, the sixth lens 106, the seventh lens 107, the ninth lens 109, and the tenth lens 110 are all positive power lenses; the third lens 103 includes a third object-side surface near the object plane and a third image-side surface near the image plane, the third object-side surface being concave and the third image-side surface being convex; the fourth lens 104 includes a fourth object-side surface near the object plane, the fourth object-side surface being convex.

[0123] Other parameters are the same as in Example 1, and will not be repeated here.

[0124] As another feasible implementation method, the specific parameters of the fixed-focus lens are explained below.

[0125] Table 7. Optical design values ​​for a fixed-focus lens in Example 3

[0126]

[0127] Table 8 Design values ​​of optical physical parameters for fixed-focus lenses

[0128]

[0129] The surface numbers in Table 8 are assigned according to the surface sequence of each lens. "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on. "STO" represents the aperture stop of the lens. "IMA" represents the image plane of the lens. The radius of curvature represents the curvature of the lens surface; a positive value indicates the surface bends towards the image plane, and a negative value indicates the surface bends towards the object plane. "Infinity" indicates the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index Nd represents the ability of the material between the current and next surfaces to deflect light; a blank space indicates the current location is air with a refractive index of 1. The Abbe number Vd represents the dispersion characteristics of the material between the current and next surfaces; a blank space indicates the current location is air. The semi-diameter represents the effective diameter of the lens. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0130] In this embodiment of the invention, the aspherical lens of the fixed-focus lens satisfies the following formula:

[0131]

[0132] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; and the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the AG aspherical polynomial.

[0133] Table 9 Aspherical coefficients of fixed-focus lenses

[0134]

[0135] Where 1.289265E-03 represents 1.289265 × 10 -3 All other parameters can be represented in this way.

[0136] This embodiment satisfies the following parameters:

[0137] Focal length: f=3.59mm;

[0138] Aperture number: F#=1.04;

[0139] The field of view (FOV) corresponding to the φ9.1mm imaging target surface is 160°.

[0140] Total optical length: TTL=36.96mm.

[0141] Figure 6This is a schematic diagram of the spherical aberration curve of a fixed-focus lens provided in Embodiment 3 of the present invention. The vertical direction represents the normalized aperture, 0 indicates that it is on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (436nm, 486nm, 546nm, 588nm, and 656nm, respectively), which are... Figure 6 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of this fixed-focus lens is well controlled at each wavelength, which can meet the requirements of wide-spectrum applications.

[0142] In summary, the fixed-focus lens provided in this embodiment of the invention adopts a 5G6P structure, with its optical power matching pattern being negative-negative-negative-positive-positive-positive-negative-positive-positive-negative. The optical power, shape, and position layout of each lens are reasonable, achieving a focal length of approximately 3.59mm. This results in clear imaging with a larger aperture (F1.04) on an imaging target surface greater than φ9.1mm. It can be matched with a 1 / 1.8-inch four-megapixel chip to meet high image quality requirements, and the field of view reaches 160°, making it suitable for a wider range of usage needs.

[0143] Example 4

[0144] Figure 7 This is a schematic diagram of the structure of a fixed-focus lens provided in Embodiment 4 of the present invention, as shown below. Figure 7 As shown, the fixed-focus lens provided in Embodiment 4 of the present invention includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, an eighth lens 108, a ninth lens 109, a tenth lens 110, and an eleventh lens 111 arranged sequentially along the optical axis from the object plane to the image plane; the first lens 101, the second lens 102, the third lens 103, the fifth lens 105, the eighth lens 108, and the eleventh lens 111 are all negative power lenses, and the fourth lens 104, the sixth lens 106, the seventh lens 107, the ninth lens 109, and the tenth lens 110 are all positive power lenses; the third lens 103 includes a third object-side surface near the object plane and a third image-side surface near the image plane, the third object-side surface being concave and the third image-side surface being convex; the fourth lens 104 includes a fourth object-side surface near the object plane, the fourth object-side surface being convex.

[0145] Other parameters are the same as in Example 1, and will not be repeated here.

[0146] As another feasible implementation method, the specific parameters of the fixed-focus lens are explained below.

[0147] Table 10. Optical design values ​​for a fixed-focus lens in Example 4

[0148]

[0149] Table 11 Design values ​​of optical physical parameters for fixed-focus lenses

[0150]

[0151] The surface numbers in Table 11 are assigned according to the surface sequence of each lens. "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and so on. "STO" represents the aperture stop of the lens. "IMA" represents the image plane of the lens. The radius of curvature represents the curvature of the lens surface; a positive value indicates the surface bends towards the image plane, and a negative value indicates the surface bends towards the object plane. "Infinity" indicates the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index Nd represents the ability of the material between the current and next surfaces to deflect light; a blank space indicates the current location is air with a refractive index of 1. The Abbe number Vd represents the dispersion characteristics of the material between the current and next surfaces; a blank space indicates the current location is air. The semi-diameter represents the effective diameter of the lens. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0152] In this embodiment of the invention, the aspherical lens of the fixed-focus lens satisfies the following formula:

[0153]

[0154] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; and the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the AG aspherical polynomial.

[0155] Table 12 Aspherical coefficients of fixed-focus lenses

[0156]

[0157] Wherein, 6.189894E-04 represents 6.189894 × 10 -4 All other parameters can be represented in this way.

[0158] This embodiment satisfies the following parameters:

[0159] Focal length: f=3.59mm;

[0160] Aperture number: F#=1.08;

[0161] The field of view (FOV) corresponding to the φ9.1mm imaging target surface is 160°.

[0162] Total optical length: TTL=39.27mm.

[0163] Figure 8 This is a schematic diagram of the spherical aberration curve of a fixed-focus lens provided in Embodiment 4 of the present invention. The vertical direction represents the normalized aperture, 0 indicates that it is on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (436nm, 486nm, 546nm, 588nm, and 656nm, respectively), which are... Figure 8 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of this fixed-focus lens is well controlled at each wavelength, which can meet the requirements of wide-spectrum applications.

[0164] In summary, the fixed-focus lens provided in this embodiment of the invention adopts a 5G6P structure, with its optical power matching pattern being negative-negative-negative-positive-positive-positive-negative-positive-positive-negative. The optical power, shape, and position layout of each lens are reasonable, achieving a focal length of approximately 3.59mm. This results in clear imaging with a larger aperture (F1.08) on a target surface larger than φ9.1mm. It can be matched with a 1 / 1.8-inch four-megapixel chip to meet high image quality requirements, and the field of view reaches 160°, making it suitable for a wider range of usage needs.

[0165] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A fixed-focus lens, characterized in that, It includes the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, tenth lens and eleventh lens arranged sequentially along the optical axis from the object plane to the image plane; The first lens, the second lens, the third lens, the fifth lens, the eighth lens, and the eleventh lens are all negative power lenses, while the fourth lens, the sixth lens, the seventh lens, the ninth lens, and the tenth lens are all positive power lenses. The third lens includes a third object-side surface near the object plane and a third image-side surface near the image plane. The third object-side surface is concave, and the third image-side surface is convex. The fourth lens includes a fourth object-side surface near the object surface, and the fourth object-side surface is convex.

2. The fixed-focus lens according to claim 1, characterized in that, The first lens has an optical power of φ1, the second lens has an optical power of φ2, the combined optical power of the third and fourth lenses is φ34, the fifth lens has an optical power of φ5, the sixth lens has an optical power of φ6, the seventh lens has an optical power of φ7, the eighth lens has an optical power of φ8, the ninth lens has an optical power of φ9, the tenth lens has an optical power of φ10, and the eleventh lens has an optical power of φ11. Where -0.67≤φ1 / φ≤-0.33, -0.18≤φ2 / φ≤-0.02, 0.07≤φ34 / φ≤0.24, 0.05≤(φ5+φ6) / φ≤0.25, 0.06≤φ7 / φ≤0.38, -0.30≤φ8 / φ≤-0.01, 0.07≤φ9 / φ≤0.41, 0.06≤φ10 / φ≤0.26; -0.16≤φ11 / φ≤-0.

01.

3. The fixed-focus lens according to claim 1, characterized in that, The aperture of the first lens is DT1, and the center thickness of the first lens is CT1. Among them, 3.03≤DT1 / CT1≤10.

87.

4. The fixed-focus lens according to claim 1, characterized in that, The first lens includes a first object-side surface near the object plane and a first image-side surface near the image plane. The first object-side surface is convex, and the first image-side surface is concave. The second lens includes a second image-side surface near the image plane, and the second image-side surface is concave. The fifth lens includes a fifth object-side surface near the object plane and a fifth image-side surface near the image plane. The fifth object-side surface is concave, and the fifth image-side surface is convex. The sixth lens includes a sixth object-side surface near the object plane and a sixth image-side surface near the image plane. The sixth object-side surface is convex, and the sixth image-side surface is convex. The seventh lens includes a seventh object-side surface near the object plane and a seventh image-side surface near the image plane. The seventh object-side surface is convex, and the seventh image-side surface is convex. The eighth lens includes an eighth object-side surface near the object plane and an eighth image-side surface near the image plane. The eighth object-side surface is concave, and the eighth image-side surface is concave. The ninth lens includes a ninth object-side surface near the object plane and a ninth image-side surface near the image plane. The ninth object-side surface is convex, and the ninth image-side surface is convex. The tenth lens includes a tenth image side surface near the image plane, and the tenth image side surface is convex. The eleventh lens includes an eleventh object-side surface near the object plane and an eleventh image-side surface near the image plane. The eleventh object-side surface is concave, and the eleventh image-side surface is convex.

5. The fixed-focus lens according to claim 4, characterized in that, The seventh lens and the eighth lens are cemented together. Alternatively, the eighth lens and the ninth lens are cemented together. Alternatively, the seventh lens, the eighth lens, and the ninth lens may be cemented together.

6. The fixed-focus lens according to claim 1, characterized in that, The first lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all glass spherical lenses; The second lens, the third lens, the fourth lens, the fifth lens, the tenth lens, and the eleventh lens are all plastic aspherical lenses.

7. The fixed-focus lens according to claim 1, characterized in that, The seventh lens has a refractive index of Nd7 and an Abbe number of Vd7; the eighth lens has a refractive index of Nd8 and an Abbe number of Vd8; and the ninth lens has a refractive index of Nd9 and an Abbe number of Vd9. Among them, 4.78≤Nd7+Nd8+Nd9≤4.90, 57.70≤Vd7≤73.30, 25.22≤Vd8≤34.64, and 57.70≤Vd9≤73.

30.

8. The fixed-focus lens according to claim 1, characterized in that, The maximum image height of the fixed-focus lens is IH, and the entrance pupil diameter of the fixed-focus lens is EPD. Among them, 2.60≤IH / EPD≤2.

79.

9. The fixed-focus lens according to claim 1, characterized in that, The fixed-focus lens has an aperture of F#, an imaging field of view of FOV, and a total optical length of TTL; Among them, F#≤1.1, FOV≥160°, TTL≤40mm.

10. The fixed-focus lens according to claim 1, characterized in that, The fixed-focus lens also includes an aperture stop and a filter, wherein the aperture stop is disposed in the optical path between the third lens and the fourth lens; The filter is disposed in the optical path between the eleventh lens and the image plane.

Images