Prime lens

Abstract

The prime lens 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 which are sequentially arranged from an object plane to an image plane along an optical axis, the first lens, the second lens, the third lens, the fifth lens, the eighth lens and the eleventh lens are all negative focal power lenses, and the fourth lens, the sixth lens, the seventh lens, the ninth lens and the tenth lens are all positive focal power lenses. The third lens comprises a third object side surface close to one side of the object plane and a third image side surface close to one side of the image plane, the third object side surface is a concave surface, and the third image side surface is a convex surface; the fourth lens comprises a fourth object side surface close to one side of the object surface, and the fourth object side surface is a convex surface. By adopting the technical scheme, at least one beneficial effect of excellent imaging, large light transmission, large target surface, wide angle and the like can be realized.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of optical devices, in particular to a fixed focus lens. BACKGROUND

[0002] In today's era of rapid technological change, the application scenarios of security lenses are constantly expanding and extending, so the needs and requirements of security lenses are further improved.

[0003] At present, security lenses mostly adopt large apertures, but it is difficult to achieve high image quality at the same time. SUMMARY

[0004] The present application provides a fixed focus lens, which realizes lens design considering large aperture and high resolution.

[0005] The embodiment of the present application provides 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.

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

[0007] 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.

[0008] The fourth lens comprises a fourth object side surface close to the object plane, and the fourth object side surface is a convex surface.

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

[0010] Wherein, -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 first lens has a clear aperture DT1 and a center thickness CT1.

[0014] Optionally, 3.03≤DT1 / CT1≤10.87.

[0015] Optionally, the first lens includes a first object side surface close to the object plane and a first image side surface close to the image plane, the first object side surface is a convex surface, and the first image side surface is a concave surface.

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

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

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

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

[0020] The eighth lens includes an eighth object side surface close to the object plane and an eighth image side surface close to the image plane, the eighth object side surface is a concave surface, and the eighth image side surface is a concave surface.

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

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

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

[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 are 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 Nd7 and an Abbe number Vd7; the eighth lens has a refractive index Nd8 and an Abbe number Vd8; and the ninth lens has a refractive index Nd9 and an Abbe number Vd9.

[0030] 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 fixed-focus lens has a maximum imaging height IH and an entrance pupil diameter EPD.

[0032] 2.60≤IH / EPD≤2.79.

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

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

[0035] Optionally, the fixed-focus lens further comprises a diaphragm and a filter, and the diaphragm is arranged in the optical path between the third lens and the fourth lens.

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

[0037] The fixed focus lens provided by the embodiment of the present application comprises eleven lenses with optical power, and the total length of the fixed focus lens can be ensured to be appropriate by reasonably setting the number of the lenses, and the fixed focus lens is relatively small in size while the imaging aberration is ensured to be small and the imaging quality is ensured to be high. Further, the optical power matching mode of the eleven lenses is negative-negative-negative-positive-negative-positive-positive-negative-positive-positive-negative, and the aperture of the optical lens can be increased and the imaging resolution of the optical lens can be improved by reasonably matching the optical power design mode of the eleven lenses. In addition, the object side surface of the third lens is concave, the image side surface of the third lens is convex, the object side surface of the fourth lens is convex, and the light entering the optical system can be effectively controlled to diverge first and then converge by reasonably designing the surface shape of the third lens and the fourth lens, so that a large aperture is further realized.

[0038] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0040] Figure 1 is a structural schematic diagram of a fixed focus lens provided by the first embodiment of the present application;

[0041] Figure 2 is a spherical aberration curve schematic diagram of the fixed focus lens provided by the first embodiment of the present application;

[0042] Figure 3 is a structural schematic diagram of a fixed focus lens provided by the second embodiment of the present application;

[0043] Figure 4 is a spherical aberration curve schematic diagram of the fixed focus lens provided by the second embodiment of the present application;

[0044] Figure 5 is a structural schematic diagram of a fixed focus lens provided by the third embodiment of the present application;

[0045] Figure 6 is a spherical aberration curve schematic diagram of the fixed focus lens provided by the third embodiment of the present application;

[0046] Figure 7 is a structural schematic diagram of a fixed focus lens provided by the fourth embodiment of the present application;

[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] Further, the optical power is equal to the difference between the converging degree of the image plane and the converging degree of the object plane, which represents the ability of the optical system to deflect light. The greater the absolute value of the optical power, the stronger the bending ability of the light, and the smaller the absolute value of the optical power, the weaker the bending ability of the light. When the optical power is positive, the refraction of the light is convergent; when the optical power is negative, the refraction of the light is divergent. The optical power can be used to represent a certain refractive surface of a lens (i.e., a surface of the lens), a certain lens, or a system formed by multiple lenses (i.e., a lens group). In the embodiment of the present application, the optical powers of the first lens 101, the second lens 102, and the third lens 103 are all negative. The first lens 101, the second lens 102, and the third lens 103 are the first lenses in the optical lens to adjust the incident light, and the negative optical power can ensure that the light has a larger aperture before entering the diaphragm, increase the aperture of the optical lens, and enable the lens to clearly image in dark or dark conditions. The positive optical power of the fourth lens 104 can correct the large aberration generated by the first lens 101, the second lens 102, and the third lens 103 in time, especially the edge aberration of the optical lens, thereby improving the imaging resolution of the optical system. Further, the optical power of the fifth lens group 105 is negative, the optical power of the sixth lens 106 is positive, the optical power of the seventh lens 107 is positive, the optical power of the eighth lens 108 is negative, the optical power of the ninth lens 109 is positive, the optical power of the tenth lens 110 is positive, and the optical power of the eleventh lens 111 is negative. The optical power of the latter lens in the optical path is different from that of the former lens, which is conducive to correcting aberration.

[0053] Further, the object side of the lens can be understood as the surface of the lens close to the object plane, and the image side of the lens can be understood as the surface of the lens close to the image plane. In the embodiment of the present application, the object side of the third lens 103 is concave, and the image side is convex, which can be understood as the object side of the third lens 103 being concave towards the object plane at the near optical axis position, and the image side being convex towards the image plane at the near optical axis position, that is, the third lens 103 is a concave-convex lens. The object side of the fourth lens 104 is convex, and the image side is convex or concave, which can be understood as the object side of the fourth lens 104 being convex towards the object plane at the near optical axis position, and the image side being convex or concave towards the image plane at the near optical axis position, that is, the third lens 103 is a double-convex lens or a convex-concave lens. By designing the third lens 103 as a concave-convex negative lens and the fourth lens 104 as a convex-concave or double-convex positive lens, the surface type and optical power of the third lens 103 and the fourth lens 104 can effectively control the light propagating in the optical lens to first diverge and then converge, which is conducive to realizing a large aperture.

[0054] In summary, the fixed focus lens provided by the embodiment of the present application comprises eleven lenses with optical power, and the total length of the fixed focus lens can be ensured appropriate by reasonably setting the number of lenses, and the fixed focus lens is relatively small in size while ensuring small imaging aberration and high imaging quality. Further, the optical power of the eleven lenses is arranged in the manner of negative-negative-negative-positive-negative-positive-positive-negative-positive-positive-negative, and the aperture of the optical lens can be increased and the imaging resolution of the optical lens can be improved by reasonably arranging the optical power of the eleven lenses. In addition, the object side of the third lens is concave, and the image side is convex, and the object side of the fourth lens is convex, and the light rays entering the optical system can be effectively controlled to diverge first and then converge by reasonably designing the surface shape of the third lens and the fourth lens, thereby further achieving a large aperture.

[0055] On the basis of the above-mentioned embodiment, with reference to Figure 1 continuously to the fixed focus lens provided by the embodiment of the present application can further comprise a diaphragm STO and a filter 112, the diaphragm STO is arranged in the optical path between the third lens 103 and the fourth lens 104, and the filter 112 is arranged in the optical path between the eleventh lens 111 and the image plane.

[0056] Specifically, the diaphragm STO can adjust the propagation direction of the light beam, which is beneficial to improve the imaging quality. In addition, in the fixed focus lens, the diaphragm STO arranged in the optical system can limit the size of the light beam and control the light quantity of the lens, which is beneficial to reduce the aperture value and achieve a large aperture. The filter 112 can filter out stray light and improve the imaging effect.

[0057] Further, the optical lens provided by the embodiment of the present application can further comprise a protective glass and an imaging sensor, the protective glass can be arranged on the image side of the filter, and the imaging sensor can be arranged on the image side of the protective glass. The optical system is protected by the protective glass, and the imaging sensor is used to collect images, thereby realizing the normal imaging function of the optical system.

[0058] On the basis of the above-mentioned 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 111 is φ11; wherein -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, and -0.16≤φ11 / φ≤-0.01.

[0059] Specifically, the optical power of the first lens 101 is set to satisfy -0.67≤φ1 / φ≤-0.33, which can ensure that the system can pass light rays at a large angle and control the incidence angle of the optical system. The optical power of the second lens 102 is set to satisfy -0.18≤φ2 / φ≤-0.02, and the optical power of the third lens 103 and the fourth lens 104 is set to satisfy 0.07≤φ34 / φ≤0.24, which can correct off-axis aberrations, optimize field curvature, and control focal length. The optical power of the fifth lens 105 and the sixth lens 106 is set to satisfy 0.05≤(φ5+φ6) / φ≤0.25, which can better balance the resolution of the lens and thus improve the image quality of the lens. The optical power of the seventh lens 107 is set to satisfy 0.06≤φ7 / φ≤0.38, the optical power of the eighth lens 108 is set to satisfy -0.30≤φ8 / φ≤-0.01, and the optical power of the ninth lens 109 is set to satisfy 0.07≤φ9 / φ≤0.41, which can correct chromatic aberration and reduce the difficulty of assembly and adjustment. The optical power of the tenth lens 110 is set to satisfy 0.06≤φ10 / φ≤0.26, and the optical power of the eleventh lens 111 is set to satisfy -0.16≤φ11 / φ≤-0.01, which is conducive to correcting the spherical aberration and chromatic aberration of the optical lens and further improving the image quality; and it can also avoid excessive pressure on the remaining lenses in the process of correcting chromatic aberration, aberration, and CRA, so that the shape is difficult to process.

[0060] On the basis of the above-mentioned embodiments, the light passing 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 that first adjusts the incident light, the corresponding relationship between the light passing aperture and the center thickness of the first lens 101 can further ensure that the optical lens can pass light rays at a large angle, control the incidence angle of the optical lens, and ensure the amount of light entering the optical lens.

[0061] On the basis of the above-mentioned embodiments, the first lens 101 comprises a first object side surface close to the object plane and a first image side surface close to the image plane, the first object side surface is convex, and the first image side surface is concave; the second lens 102 comprises a second image side surface close to the image plane, and the second image side surface is concave; the fifth lens 105 comprises a fifth object side surface close to the object plane and a fifth image side surface close to the image plane, the fifth object side surface is concave, and the fifth image side surface is convex; the sixth lens 106 comprises a sixth object side surface close to the object plane and a sixth image side surface close to the image plane, the sixth object side surface is convex, and the sixth image side surface is convex; the seventh lens 107 comprises a seventh object side surface close to the object plane and a seventh image side surface close to the image plane, the seventh object side surface is convex, and the seventh image side surface is convex; the eighth lens 108 comprises an eighth object side surface close to the object plane and an eighth image side surface close to the image plane, the eighth object side surface is concave, and the eighth image side surface is concave; the ninth lens 109 comprises a ninth object side surface close to the object plane and a ninth image side surface close to the image plane, the ninth object side surface is convex, and the ninth image side surface is convex; the tenth lens 110 comprises a tenth image side surface close to the image plane, and the tenth image side surface is convex; the eleventh lens 111 comprises an eleventh object side surface close to the object plane and an eleventh image side surface close to 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, which can be understood as that the object side surface of the first lens 101 protrudes towards the object plane at the position close to the optical axis, and the image side surface is concave at the position close to the optical axis, that is, the first lens 101 is a meniscus lens with convex-concave structure. The object side surface of the first lens is designed to be convex, which can converge light into the system as much as possible, and the image side surface is designed to be concave, which can make the light enter the system with a smaller deflection angle, which is beneficial to realize a larger aperture and smaller aberration.

[0063] The object side surface of the second lens 102 can be convex or concave, and the image side surface is concave, which can be understood as that the object side surface of the second lens 102 protrudes towards the object plane or is concave at the position close to the optical axis, and the image side surface is concave at the position close to the optical axis, that is, the second lens 102 is a lens with convex-concave structure or double-concave structure.

[0064] The object side surface of the fifth lens 105 is concave, and the image side surface is convex, which can be understood as that the object side surface of the fifth lens 105 is concave at the position close to the optical axis, and the image side surface protrudes towards the image plane at the position close to the optical axis, that is, the fifth lens 105 is a lens with 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] On the basis of the above-mentioned embodiments, the seventh lens 107 and the eighth lens 108 are cemented; or the eighth lens 108 and the ninth lens 109 are cemented; or the seventh lens 107, the eighth lens 108 and the ninth lens 109 are cemented.

[0071] Specifically, the cemented arrangement of different lenses can be understood as that the image side surface of a previous lens in the optical path is attached to the object side surface of a subsequent lens, and has the same surface type. In the embodiments of the present application, the seventh lens 107 and the eighth lens 108 are cemented, as shown in FIG. 1B; or the eighth lens 108 and the ninth lens 109 are cemented; or the seventh lens 107, the eighth lens 108 and the ninth lens 109 are cemented. Figure 1 The cemented arrangement of the seventh lens 107 and the eighth lens 108 can be understood as that the image side surface of the seventh lens 107 is attached to the object side surface of the eighth lens 108 to form two cemented lenses; the cemented arrangement of the eighth lens 108 and the ninth lens 109 can be understood as that the image side surface of the eighth lens 108 is attached to the object side surface of the ninth lens 109 to form two cemented lenses; and the cemented arrangement of the seventh lens 107, the eighth lens 108 and the ninth lens 109 can be understood as that the image side surface of the seventh lens 107 is attached to the object side surface of the eighth lens 108 and the image side surface of the eighth lens 108 is attached to the object side surface of the ninth lens 109 to form three cemented lenses. The cemented lenses can be used to minimize chromatic aberration or eliminate chromatic aberration, and the use of cemented lenses in optical lenses can improve image quality and reduce reflection loss of light energy, thereby improving the clarity of lens imaging. In addition, the cementing of lenses omits the air gap between two lenses, so that the overall optical lens is compact, meeting the system miniaturization requirement. Moreover, the cementing of lenses can reduce the tolerance sensitivity problems such as tilt and eccentricity of lens units in the assembly process.

[0072] In addition, the two or three lenses cemented can be supported by a gasket or can be cemented by glue, and the specific implementation mode of cementing is not limited in the embodiments of the present application.

[0073] On the basis of the above-mentioned 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; and 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, the non-spherical lens is characterized in that the curvature continuously changes from the center of the lens to the periphery of the lens, which is different from the spherical lens having a constant curvature from the center of the lens to the periphery of the lens. The non-spherical lens has better curvature radius characteristics, and has the advantages of improving the distortion aberration and improving the astigmatism aberration. 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 non-spherical lenses. The plastic non-spherical lens is provided to reduce the processing technology of the non-spherical lens, and the cost of the non-spherical lens is relatively low, so that the cost of the optical system can be reduced.

[0075] The spherical lens is characterized in that the curvature is constant from the center of the lens to the periphery of the lens, which ensures that the lens is simple in arrangement. Further, since the thermal expansion coefficient of the glass material is small and the stability is good, 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 thermal properties of the glass spherical lens are more stable, and when a large amount of optical power is borne, the lens can have good resolving power in a wide temperature range. Furthermore, the range of glass materials that can be selected is wider, the refractive index and Abbe number are relatively free to choose, which can control the high-order aberration and chromatic aberration of the lens to a certain extent, and meet the use requirements under complex conditions.

[0076] Therefore, in the fixed focus lens provided by the embodiment of the present application, the glass spherical lens and the plastic non-spherical lens can be mixed and matched, so that the optical performance of the fixed focus lens can be ensured while the cost of the fixed focus lens can be effectively controlled. Meanwhile, the materials of the lenses have a mutual compensation effect, so that the lenses can still be normally used in high and low temperature environments.

[0077] On the basis of the above embodiment, 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; 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 the range, the chromatic aberration of the optical lens can be ensured, so that high image quality can be achieved.

[0078] On the basis of the above embodiment, the maximum imaging 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. The above relationship can control the entrance pupil diameter of the optical lens while the optical lens meets the requirements of large target surface and high-quality imaging, so that the edge field angle of the large target surface imaging system can be ensured to be sufficient, and the image plane brightness can be improved.

[0079] On the basis of the above-mentioned embodiments, the aperture number of the fixed focus lens is F#, the imaging field of view angle is FOV, and the total optical length is TTL; wherein F#≤1.1, FOV≥160°, and TTL≤40mm. That is, the fixed focus lens with large aperture, large field of view, and small total optical length is realized.

[0080] As a feasible implementation manner, the parameters of each lens in the fixed focus lens are described as follows.

[0081] Table 1: An optical design value of the fixed focus lens in the first embodiment

[0082]

[0083] Table 2: A design value of the optical physical parameters of the fixed focus lens

[0084]

[0085] The surface serial number in Table 2 is numbered according to the surface order of each lens, wherein “S1” represents the front surface of the first lens, “S2” represents the rear surface of the first lens, and the like is sequentially continued; “STO” represents the diaphragm of the lens; “IMA” represents the image surface of the lens; the curvature radius represents the bending degree of the lens surface, the positive value represents that the surface is bent to the image side, and the negative value represents that the surface is bent to the object side, wherein “Infinity” represents that the surface is a plane, the curvature radius is infinite, and the distance is infinite; the thickness represents the center axis distance from the current surface to the next surface; the refractive index Nd represents the deflection ability of the material between the current surface and the next surface; the space represents that the current position is air, and the refractive index is 1; the Abbe number Vd represents the dispersion characteristics of the material between the current surface and the next surface, and the space represents that the current position is air; the half diameter represents the effective diameter of the light of the lens; and the k value represents the numerical size of the conic coefficient of the aspheric surface.

[0086] In the embodiment of the application, the aspheric lens of the fixed focus lens satisfies the following formula:

[0087]

[0088] Wherein, z is the axial height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitting sphere, which is the reciprocal of the curvature radius in the numerical value; k is the fitting conic coefficient; A-G is the 4th order, 6th order, 8th order, 10th order, 12th order, 14th order, and 16th order term coefficient of the aspheric polynomial.

[0089] Table 3: Aspheric surface coefficients of the fixed focus lens

[0090]

[0091] Wherein, 1.452713E-03 represents 1.452713*10 -3 The rest of the parameters can be represented in this way.

[0092] The following parameters are met in this embodiment:

[0093] Focal length: f=3.62mm;

[0094] F-number: F#=1.08;

[0095] φ9.1mm imaging target surface corresponding field angle: FOV=160°;

[0096] Optical total length: TTL=36.62mm.

[0097] Figure 2 is a schematic diagram of the spherical aberration curve of a fixed focus lens provided by the first embodiment of the present application, the normalized aperture is represented in the vertical direction, 0 represents on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset amount relative to the ideal focus point, with units of millimeters (mm). Different linear curves in the figure represent different wavelengths (436nm, 486nm, 546nm, 588nm and 656nm, respectively) of system imaging, and the spherical aberration curve of the fixed focus lens is shown in the figure. Figure 2 It can be seen that the axial aberration of different wavelengths is controlled within the range of (-0.05mm, +0.05mm), which shows that the spherical aberration of the fixed focus lens at each wavelength is well controlled, and can meet the wide spectrum application requirement.

[0098] In summary, the fixed focus lens provided by the embodiment of the present application adopts the structure of 5G6P, the refractive power matching mode is negative-negative-negative-positive-negative-positive-positive-negative-positive-negative, the refractive power, shape and position layout of each lens are reasonable, and a fixed focus lens with a focal length of about 3.62mm is realized, which has a larger aperture under the imaging target surface > φ9.1mm target surface, reaches F1.08, can match a 1 / 1.8 inch four million pixel chip, meets the high image quality requirement, the field angle reaches 160°, and is suitable for more situations.

[0099] Embodiment two

[0100] Figure 3 is a structural schematic diagram of a fixed focus lens provided by the second embodiment of the present application, as Figure 3As shown, the fixed focus lens provided by the second embodiment of the present application comprises, in order along the optical axis from the object plane to the image plane, 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; 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 negative focal 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 positive focal power lenses; the third lens 103 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; the fourth lens 104 comprises a fourth object side surface close to the object plane, and the fourth object side surface is a convex surface.

[0101] Other parameters are the same as those in the first embodiment, which will not be repeated here.

[0102] As another possible implementation, the specific parameters in the fixed focus lens are described as follows.

[0103] Table 4: One optical design value of the fixed focus lens in the second embodiment

[0104]

[0105] Table 5: Design value of optical physical parameters of the fixed focus lens

[0106]

[0107] The surface number in Table 5 is numbered according to the surface order of each lens, wherein "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and the like; "STO" represents the stop of the lens; "IMA" represents the image plane of the lens; the radius of curvature represents the bending degree of the lens surface, a positive value represents that the surface is bent toward the image plane side, and a negative value represents that the surface is bent toward the object plane side, wherein "Infinity" represents that the surface is a plane, the radius of curvature is infinite, and the distance is infinite; the thickness represents the center axis distance from the current surface to the next surface; the refractive index Nd represents the light deflection ability of the material between the current surface and the next surface; the space represents that the current position is air, and the refractive index is 1; the Abbe number Vd represents the chromatic dispersion characteristic of the material between the current surface and the next surface, and the space represents that the current position is air; the half diameter represents the effective diameter of the light of the lens; and the k value represents the numerical size of the conic coefficient of the aspheric surface.

[0108] In the embodiment of the present application, the aspheric lens of the fixed focus lens satisfies the following formula:

[0109]

[0110] Wherein, z is the axial height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitting sphere, which is the reciprocal of the radius of curvature in value; k is the fitting conic coefficient; A-G are the 4th order, 6th order, 8th order, 10th order, 12th order, 14th order and 16th order term coefficients of the aspheric surface polynomial.

[0111] Table 6 Aspheric surface coefficients of the fixed focus lens

[0112]

[0113] Wherein, 1.008381E-03 represents 1.008381*10 -3 The remaining parameters can be represented in this manner.

[0114] The embodiment meets the following parameters:

[0115] Focal length: f=3.59mm;

[0116] F-number: F#=1.08;

[0117] φ9.1mm imaging target surface corresponding field angle: FOV=160°;

[0118] Optical total length: TTL=36.82mm.

[0119] Figure 4 is a schematic diagram of the spherical aberration curve of the fixed focus lens provided in the second embodiment of the application, the normalized aperture is represented in the vertical direction, 0 represents on the optical axis, and the vertical direction vertex represents the maximum pupil radius; the horizontal direction represents the offset amount relative to the ideal focus point, with the unit of millimeter (mm). Different linear curves in the figure represent different wavelengths (436nm, 486nm, 546nm, 588nm and 656nm) of system imaging, and the spherical aberration curve of the fixed focus lens is shown in the figure. Figure 4 It can be seen that the axial aberration of different wavelengths is controlled within the range of (-0.05mm, +0.05mm), which indicates that the spherical aberration of the fixed focus lens at each wavelength is well controlled, and the wide spectrum application requirement can be met.

[0120] In summary, the fixed focus lens provided in the embodiment of the application adopts the structure of 5G6P, the refractive power matching mode is negative-negative-negative-positive-negative-positive-positive-negative-positive-negative, the refractive power, shape and position layout of each lens are reasonable, a focal length of about 3.59mm is realized, the imaging is clear under the imaging target surface >φ9.1mm target surface, the aperture is larger, reaches F1.08, can match 1 / 1.8 inch four million pixel chips, meets the high image quality requirement, the field angle reaches 160°, and is suitable for more situation use requirements.

[0121] Embodiment three

[0122] Figure 5 is a structural schematic diagram of a fixed focus lens provided by Embodiment three of the present application, as shown in the figure, the fixed focus lens provided by Embodiment three of the present application comprises, in order along the optical axis from the object plane to the image plane, 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; 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 focal 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 focal power lenses; the third lens 103 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; the fourth lens 104 comprises a fourth object side surface close to the object plane, and the fourth object side surface is a convex surface. Figure 5

[0123] Other parameters are the same as those in Embodiment one, and will not be described here.

[0124] As another possible implementation, the specific parameters in the fixed focus lens are described below.

[0125] Table 7 Optical design values of the fixed focus lens in Embodiment three

[0126]

[0127] Table 8 Design values of optical physical parameters of the fixed focus lens

[0128]

[0129] ​The surface sequence number in Table 8 is numbered according to the surface sequence of each lens, wherein "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and the like; "STO" represents the diaphragm of the lens; "IMA" represents the image surface of the lens; the radius of curvature represents the bending degree of the lens surface, a positive value represents that the surface is bent to the image surface side, and a negative value represents that the surface is bent to the object surface side, wherein "Infinity" represents that the surface is a plane, the radius of curvature is infinite, and the distance is infinite; the thickness represents the central axis distance from the current surface to the next surface; the refractive index Nd represents the deflection ability of the material between the current surface and the next surface; the space represents that the current position is air, and the refractive index is 1; the Abbe number Vd represents the dispersion characteristics of the material between the current surface and the next surface, and the space represents that the current position is air; the half diameter represents the effective diameter of the lens; and the k value represents the numerical size of the conic coefficient of the aspheric surface.

[0130] In the embodiment of the application, the aspheric lens of the fixed-focus lens satisfies the following formula:

[0131]

[0132] wherein z is the axial height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitting sphere, and the numerical value is the reciprocal of the radius of curvature; k is the fitting conic coefficient; A-G are the 4th order, 6th order, 8th order, 10th order, 12th order, 14th order and 16th order term coefficients of the aspheric polynomial.

[0133] Table 9: Aspheric surface coefficients of the fixed-focus lens

[0134]

[0135] wherein 1.289265E-03 represents 1.289265*10 -3 The remaining parameters can be represented in this manner.

[0136] The embodiment satisfies the following parameters:

[0137] Focal length: f = 3.59 mm;

[0138] F-number: F# = 1.04;

[0139] φ9.1 mm imaging target surface corresponding field angle: FOV = 160°;

[0140] Optical total length: TTL = 36.96 mm.

[0141] Figure 6is a schematic diagram of the spherical aberration curve of the fixed focus lens provided in Embodiment Three, the vertical direction represents the normalization of the aperture, 0 represents on the optical axis, and the vertical top represents the maximum pupil radius; the horizontal direction represents the offset amount relative to the ideal focus point, with the unit of millimeter (mm). Different linear curves in the figure represent different wavelengths (436 nm, 486 nm, 546 nm, 588 nm and 656 nm, respectively) of system imaging, and the curve is obtained by Figure 6 It can be seen that the axial aberration of different wavelengths is controlled within the range of (-0.05 mm, +0.05 mm), which indicates that the spherical aberration of the fixed focus lens at each wavelength is well controlled, and the wide spectrum application requirement can be met.

[0142] In summary, the fixed focus lens provided in the embodiment of the present application adopts the structure of 5G6P, the refractive power matching mode is negative-negative-negative-positive-negative-positive-positive-negative-positive-positive-negative, the refractive power, shape and position layout of each lens are reasonable, a focal length of about 3.59 mm is realized, the imaging target surface is greater than φ9.1 mm, the imaging is clear and the aperture is larger, reaching F1.04, which can match a 1 / 1.8 inch four million pixel chip, so as to meet the high image quality requirement, and the field of view reaches 160°, which is suitable for more use requirements in more situations.

[0143] Embodiment Four

[0144] Figure 7 is a structural schematic diagram of a fixed focus lens provided in Embodiment Four, as shown in Figure 7 The fixed focus lens provided in Embodiment Four includes, arranged in order along the optical axis from the object plane to the image plane, 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; 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 negative refractive 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 positive refractive power lenses; the third lens 103 includes 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; the fourth lens 104 includes a fourth object side surface close to the object plane, and the fourth object side surface is a convex surface.

[0145] Other parameters are the same as those in Embodiment One, which will not be described here.

[0146] As another possible implementation manner, the specific parameters in the fixed focus lens are described below.

[0147] Table 10. Design values of one optical design of the fixed focus lens in Example Four

[0148]

[0149] Table 11. Design values of optical physical parameters of the fixed focus lens

[0150]

[0151] The surface serial number in Table 11 is numbered according to the surface order of each lens, wherein "S1" represents the front surface of the first lens, "S2" represents the rear surface of the first lens, and the like; "STO" represents the stop of the lens; "IMA" represents the image surface of the lens; the radius of curvature represents the bending degree of the lens surface, a positive value represents that the surface is bent to the image side, and a negative value represents that the surface is bent to the object side, wherein "Infinity" represents that the surface is a plane, the radius of curvature is infinite, and the distance is infinite; the thickness represents the center axis distance from the current surface to the next surface; the refractive index Nd represents the light deflection ability of the material between the current surface and the next surface; the space represents that the current position is air, and the refractive index is 1; the Abbe number Vd represents the chromatic dispersion characteristics of the material between the current surface and the next surface, and the space represents that the current position is air; the half diameter represents the effective diameter of the light of the lens; and the k value represents the numerical size of the conic coefficient of the aspheric surface.

[0152] In the embodiment of the present application, the aspheric lens of the fixed focus lens satisfies the following formula:

[0153]

[0154] wherein z is the axial height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitting sphere, which is the reciprocal of the radius of curvature in the numerical value; k is the fitting conic coefficient; A-G are the 4th order, 6th order, 8th order, 10th order, 12th order, 14th order and 16th order term coefficients of the aspheric polynomial.

[0155] Table 12. Aspheric surface coefficients of the fixed focus lens

[0156]

[0157] wherein 6.189894E-04 represents 6.189894x10 -4 The remaining parameters can also be expressed in this manner.

[0158] The embodiment satisfies the following parameters:

[0159] Focal length: f = 3.59 mm;

[0160] F-number: F# = 1.08;

[0161] φ9.1mm imaging target surface corresponding field angle: FOV=160°;

[0162] Optical total length: TTL=39.27mm.

[0163] Figure 8 is a schematic diagram of the spherical aberration curve of a fixed focus lens provided by the fourth embodiment of the present application, the vertical direction represents the normalized aperture, 0 represents the optical axis, and the vertical top point represents the maximum pupil radius; the horizontal direction represents the relative ideal focus offset, with units of millimeters (mm). Different linear curves in the figure represent different wavelengths (436nm, 486nm, 546nm, 588nm and 656nm respectively) of system imaging, and the horizontal axis represents the relative ideal focus offset, with units of millimeters (mm). Figure 8 It can be seen that the axial aberration of different wavelengths is controlled within the range of (-0.05mm, +0.05mm), which shows that the spherical aberration of the fixed focus lens at each wavelength is well controlled, and can meet the wide spectrum application requirement.

[0164] In summary, the fixed focus lens provided by the embodiment of the present application adopts the structure of 5G6P, the refractive power matching mode is negative-negative-negative-positive-negative-positive-positive-negative-positive-negative, the refractive power, shape and position layout of each lens are reasonable, a focal length of about 3.59mm is realized, the imaging is clear under the imaging target surface >φ9.1mm target surface, and the aperture is larger, reaching F1.08, which can match a 1 / 1.8 inch four million pixel chip, to meet the high image quality requirement, the field angle reaches 160°, and is suitable for more situations of use requirement.

[0165] The above specific embodiments do not constitute a limitation on the protection scope of the present application. 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 modification, equivalent replacement and improvement within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A fixed focus lens characterized in that, The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens and the eleventh lens are arranged in sequence 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 negative focal length lenses, and the fourth lens, the sixth lens, the seventh lens, the ninth lens and the tenth lens are positive focal length 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; The fourth lens comprises a fourth object side surface close to the object plane, and the fourth object side surface is a convex surface.

2. The fixed focal length lens of claim 1, wherein, The focal length of the first lens is φ1, the focal length of the second lens is φ2, the combined focal length of the third lens and the fourth lens is φ34, the focal length of the fifth lens is φ5, the focal length of the sixth lens is φ6, the focal length of the seventh lens is φ7, the focal length of the eighth lens is φ8, the focal length of the ninth lens is φ9, the focal length of the tenth lens is φ10, and the focal length of the eleventh lens is φ11; Wherein, -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 of claim 1, wherein The first lens has a light transmission aperture DT1, and the first lens has a central thickness CT1; Wherein, 3.03≤DT1 / CT1≤10.

87.

4. The fixed focus lens of claim 1, wherein The first lens comprises a first object side surface close to the object plane and a first image side surface close to the image plane, the first object side surface is a convex surface, and the first image side surface is a concave surface; The second lens comprises a second image side surface close to the image plane, and the second image side surface is a concave surface; The fifth lens comprises a fifth object side surface close to the object plane and a fifth image side surface close to the image plane, the fifth object side surface is a concave surface, and the fifth image side surface is a convex surface; The sixth lens comprises a sixth object side surface close to the object plane and a sixth image side surface close to the image plane, the sixth object side surface is a convex surface, and the sixth image side surface is a convex surface; The seventh lens comprises a seventh object side surface close to the object plane and a seventh image side surface close to the image plane, the seventh object side surface is a convex surface, and the seventh image side surface is a convex surface; The eighth lens comprises an eighth object side surface close to the object plane and an eighth image side surface close to the image plane, the eighth object side surface is a concave surface, and the eighth image side surface is a concave surface; The ninth lens comprises a ninth object-side surface close to the object plane and a ninth image-side surface close to the image plane, the ninth object-side surface is a convex surface, and the ninth image-side surface is a convex surface; The tenth lens comprises a tenth image-side surface close to the image plane, the tenth image-side surface is a convex surface; The eleventh lens comprises an eleventh object-side surface close to the object plane and an eleventh image-side surface close to the image plane, the eleventh object-side surface is a concave surface, and the eleventh image-side surface is a convex surface.

5. The fixed focus lens of claim 4, wherein, 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 are cemented together.

6. The fixed focus lens of claim 1, wherein, 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 of claim 1, wherein, The refractive index of the seventh lens is Nd7, and the Abbe number is Vd7; the refractive index of the eighth lens is Nd8, and the Abbe number is Vd8; the refractive index of the ninth lens is Nd9, and the Abbe number is Vd9; 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 of claim 1, wherein, The maximum imaging height of the fixed-focus lens is IH, and the entrance pupil diameter of the fixed-focus lens is EPD; 2.60≤IH / EPD≤2.

79.

9. The fixed focus lens of claim 1, wherein, The aperture number of the fixed-focus lens is F#, the imaging field of view is FOV, and the total optical length is TTL; F#≤1.1, FOV≥160°, and TTL≤40mm.

10. The fixed lens according to claim 1, characterized in that, The fixed-focus lens further comprises a diaphragm and a filter, the diaphragm is arranged in the optical path between the third lens and the fourth lens; The filter is arranged in the optical path between the eleventh lens and the image plane.

Images