Four-piece high-NA near-infrared wide-angle telecentric high-resolution lens

Abstract

The invention discloses a four-piece high-NA near-infrared wide-angle telecentric high-resolution lens, and belongs to the technical field of optical imaging lens design, and the four-piece high-NA near-infrared wide-angle telecentric high-resolution lens is sequentially provided with a first lens, a second lens, a third lens and a fourth lens from an object side to an image side along an optical axis at intervals; the first lens has negative refractive power, the object side surface is a convex surface, and the image side surface is a concave surface; the second lens has negative refractive power, the object side surface is a concave surface, and the image side surface is a convex surface; the third lens has positive refractive power, the object side surface is a convex surface, and the image side surface is a concave surface; the fourth lens element with positive refractive power has a convex object-side surface and a convex image-side surface. According to the four-piece high-NA near-infrared wide-angle telecentric high-resolution lens provided by the invention, the refractive power and the surface type of each lens are reasonably distributed, and reasonable parameter setting is matched, so that the performance in a complex environment is provided, and the wide-angle lens is wide in application.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging lens design, and in particular to a four-piece high-NA near-infrared wide-angle telecentric high-resolution lens. Background Art

[0002] Since wide-angle lenses have the characteristics of a large shooting range and capturing more content, they can be used in some fields that have special requirements for imaging range, such as sports cameras, drones, vehicle-mounted imaging, and conference video equipment. As the demand for wide-angle lenses in these fields continues to increase, the requirements for the imaging quality of wide-angle lenses are getting higher and higher.

[0003] Wide-angle lenses in these fields have a wide range of application scenarios. They can be used in complex environments such as severe vibration, high pressure, or high and low temperatures. Therefore, higher performance requirements are placed on wide-angle lenses. Wide-angle lenses not only need to have good thermal stability to cope with variable use environments such as high and low temperatures, but also need to have a small size and weight, and be able to be paired with high-pixel chips to meet the application of different use scenarios. However, traditional wide-angle lenses have poor performance in the above complex environments and are difficult to meet the use requirements of the above complex environments. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a four-piece high-NA near-infrared wide-angle telecentric high-resolution lens. By reasonably allocating the refractive power and surface shape of each lens and matching reasonable parameter settings, the present invention provides performance in complex environments, thereby enabling wide-angle lenses to be widely used.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions: The present invention provides a four-piece high-NA near-infrared wide-angle telecentric high-resolution lens, which is provided with a first lens, a second lens, a third lens and a fourth lens in sequence with air gaps between them from the object side to the image side along the optical axis; The first lens has negative refractive power, the object side surface is convex, and the image side surface is concave; The second lens has negative refractive power, the object side surface is concave, and the image side surface is convex; The third lens has positive refractive power, the object side surface is convex, and the image side surface is concave; The fourth lens has positive refractive power, an object-side surface is convex, and an image-side surface is convex.

[0006] Furthermore, the lens satisfies: 26≤F2 / F≤10, wherein F2 is the effective focal length of the second lens, and F is the total effective focal length of the wide-angle lens.

[0007] Furthermore, the lens satisfies: -4≤F1 / F≤-1.7, wherein F1 is the effective focal length of the first lens.

[0008] Furthermore, the lens satisfies: 2.5≤F3 / F≤4, wherein F3 is the effective focal length of the third lens.

[0009] Furthermore, the lens satisfies: -3≤D / F1≤-1, wherein D is the maximum optical aperture of the wide-angle lens, and F1 is the effective focal length of the first lens.

[0010] Furthermore, the lens satisfies: -1≤F4 / F1≤-2, wherein F4 is the effective focal length of the fourth lens, and F1 is the effective focal length of the first lens.

[0011] Furthermore, the lens satisfies: -0.8≤(R21-R22) / (R21+R22)≤0.3, wherein R21 is the radius of curvature of the object side surface of the second lens, and R22 is the radius of curvature of the image side surface of the second lens.

[0012] Furthermore, the lens satisfies: 2≤F23 / F≤5, wherein F23 is the combined focal length of the second lens and the third lens.

[0013] Furthermore, the lens also satisfies: -0.8≤F12 / F34≤0, wherein F12 is the combined focal length of the first lens and the second lens, and F34 is the combined focal length of the third lens and the fourth lens.

[0014] Furthermore, the lens satisfies: 0.1≤T23 / F23≤1, wherein T23 is an air interval between the second lens and the third lens on the optical axis, and F23 is a combined focal length of the second lens and the third lens.

[0015] Furthermore, the lens satisfies: 0.3≤∑CT / TTL≤0.6, wherein ∑CT is the sum of the center thickness of each lens from the first lens to the fourth lens on the optical axis, and TTL is the total optical length of the wide-angle lens.

[0016] Furthermore, the lens satisfies: 0≤T12 / TTL≤0.3, wherein T12 is the air interval between the first lens and the second lens on the optical axis, and TTL is the total optical length of the wide-angle lens.

[0017] Furthermore, the lens satisfies: 1≤ET1 / CT1≤3, wherein ET1 is the edge thickness of the first lens, and CT1 is the center thickness of the first lens on the optical axis.

[0018] Furthermore, the lens satisfies: 0.5≤ET3 / CT3≤1.2, wherein ET3 is the edge thickness of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0019] Further, the lens satisfies: 1≤(CT3+CT4) / T34≤5, wherein CT3 is the center thickness of the third lens on the optical axis, CT4 is the center thickness of the fourth lens on the optical axis, and T34 is the air interval between the third lens and the fourth lens on the optical axis.

[0020] Furthermore, the lens satisfies: 3.5≤TTL / IH≤5, wherein TTL is the total optical length of the wide-angle lens, and IH is the maximum image height corresponding to the maximum field angle of the wide-angle lens.

[0021] Furthermore, the lens satisfies: 4≤IH / ENPD≤5.5, wherein IH is a maximum image height corresponding to a maximum field angle of the wide-angle lens, and ENPD is an entrance pupil diameter of the wide-angle lens.

[0022] Furthermore, the lens also satisfies: 0.8≤BFL / F≤2, wherein BFL is the back focal length of the wide-angle lens, and F is the total effective focal length of the wide-angle lens.

[0023] Furthermore, the image side surface of the fourth lens has at least one inflection point; And / or, an aperture is arranged between the second lens and the third lens.

[0024] Furthermore, at least one of the object-side surface and the image-side surface of the first lens, the second lens, the third lens and the fourth lens is an aspherical mirror surface.

[0025] Furthermore, the object side surface of the first lens, the object side surface and the image side surface of the third lens and the fourth lens are all aspherical mirror surfaces, and the surface shape of each aspherical lens is x The aspheric formula is expressed as: ; In the formula, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R, that is, the paraxial curvature c is the inverse of the curvature radius R; k is the cone coefficient; Ai is the coefficient of the higher order term.

[0026] Beneficial effects achieved by the present invention: The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens provided by the present invention is provided with a first lens, a second lens, a third lens and a fourth lens arranged in sequence with air gaps between them along the optical axis from the object side to the image side. By reasonably allocating the refractive power and the surface shape of each lens and matching reasonable parameter settings, the wide-angle lens can be applied to high and low temperature environments (-40°C-80°C), and at least one of the beneficial effects of the wide-angle lens including high resolution, large field of view (120°), large NA (NA=about 0.35), telecentricity, large image surface (maximum image height IH corresponding to the maximum field of view ≥10mm), small distortion (F-θ≤11%), and miniaturization can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic structural diagram of a wide-angle lens according to Embodiment 1 of the present application is shown.

[0028] Figure 2 A schematic structural diagram of a wide-angle lens according to Embodiment 2 of the present application is shown.

[0029] Figure 3 A schematic structural diagram of a wide-angle lens according to Embodiment 3 of the present application is shown.

[0030] In the figure: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Aperture STO; 6. Imaging surface IMA. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0034] like Figure 1~Figure 3 As shown, in an embodiment of the present invention, a four-piece high-NA near-infrared wide-angle telecentric high-resolution lens is provided, which may include a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4. The four lenses are arranged in sequence from the object side to the image side along the optical axis. There may be an air gap between adjacent two lenses among the first lens 1 to the fourth lens 4.

[0035] In an exemplary embodiment, the first lens 1 may have a negative refractive power. The object side surface of the first lens 1 may be a convex surface, and the image side surface may be a concave surface. By setting the first lens 1 in the above-mentioned structural form, the incident angle of the light on the object side surface of the first lens 1 can be small, and the light can smoothly reach the rear system through the first lens 1, which is conducive to achieving a large field of view of the wide-angle lens.

[0036] In an exemplary embodiment, the second lens 2 may have a negative refractive power. The object side surface of the second lens 2 may be a concave surface, and the image side surface may be a convex surface. By setting the second lens 2 as a negative lens, the light between the first lens 1 and the second lens 2 can be made to move smoothly, ensuring that the light emitted by the first lens 1 is well received by the second lens 2, reducing the loss of light in each field of view, and improving the relative illumination of each field of view.

[0037] In an exemplary embodiment, the third lens 3 may have positive refractive power. The object side surface of the third lens 3 may be convex, and the image side surface may be concave. By setting the third lens 3 as a positive lens, it is beneficial to reduce the deflection angle of the light while converging the light, so that the light trend transitions smoothly.

[0038] In an exemplary embodiment, the fourth lens 4 may have a positive refractive power. The object side surface of the fourth lens 4 may be a convex surface, and the image side surface may be a convex surface. By setting the fourth lens 4 in the above-mentioned structural form, it is beneficial to effectively transmit the light regulated by each lens to the imaging surface, thereby ensuring that the wide-angle lens realizes the characteristic of a large image surface.

[0039] As a specific example, the image side surface of the fourth lens 4 has at least one inflection point. By making the image side surface of the fourth lens 4 have at least one inflection point, it is helpful to raise the light and make the light smoothly transition to the imaging surface, so as to realize a large image surface of the telecentric wide-angle lens.

[0040] In an exemplary embodiment, the wide-angle lens may further include a stop. The stop may be disposed between the second lens 2 and the third lens 3.

[0041] In an exemplary embodiment, the wide-angle lens may also satisfy: -3≤D / F1≤-1, where D is the maximum optical aperture of the wide-angle lens, and F1 is the effective focal length of the first lens 1. By constraining the ratio of the maximum optical aperture of the wide-angle lens to the effective focal length of the first lens 1, light rays with large angles can be incident on the system, thereby effectively increasing the field of view of the wide-angle lens.

[0042] In an exemplary embodiment, the wide-angle lens may also satisfy: -4≤F1 / F≤-1.7, where F1 is the effective focal length of the first lens 1, and F is the total effective focal length of the wide-angle lens. By constraining the ratio of the effective focal length of the first lens 1 to the total effective focal length of the wide-angle lens, the field of view of the wide-angle lens can be increased, and the wide-angle characteristic of the wide-angle lens can be achieved.

[0043] In an exemplary embodiment, the wide-angle lens may also satisfy: -0.8≤(R21-R22) / (R21+R22)≤0.3, where R21 is the radius of curvature of the object side surface of the second lens 2, and R22 is the radius of curvature of the image side surface of the second lens 2. Configuring the radius of curvature of the object side surface and the image side surface of the second lens 2 can effectively converge light of a large angle field of view, and can also reduce the aberration generated by the first lens 1, thereby achieving high resolution of the wide-angle lens.

[0044] In an exemplary embodiment, the wide-angle lens may also satisfy: 2.5≤F3 / F≤4, where F3 is the effective focal length of the third lens 3, and F is the total effective focal length of the wide-angle lens. By constraining the ratio of the effective focal length of the third lens 3 to the total effective focal length of the wide-angle lens, it is beneficial to the smooth transmission of light, and the aberration of the wide-angle lens can be effectively corrected, thereby improving the imaging quality of the wide-angle lens.

[0045] In an exemplary embodiment, the wide-angle lens may also satisfy: -1≤F4 / F1≤-2, where F1 is the effective focal length of the first lens 1, and F4 is the effective focal length of the fourth lens 4. By constraining the ratio of the effective focal length of the fourth lens 4 to the effective focal length of the first lens 1, it is possible to avoid the refractive power of the wide-angle lens being concentrated on the first lens 1, thereby reducing the sensitivity of the first lens 1. At the same time, the fourth lens 4 can be used to balance the spherical aberration and field curvature that are not completely eliminated by the three front lenses, thereby improving the imaging quality of the wide-angle lens.

[0046] In an exemplary embodiment, the wide-angle lens may also satisfy: 2≤F23 / F≤5, where F23 is the combined focal length of the second lens 2 and the third lens 3, and F is the total effective focal length of the wide-angle lens. By constraining the ratio of the combined focal length of the third lens 3 and the fourth lens 4 to the total effective focal length of the wide-angle lens, the light trend between the second lens 2 and the third lens 3 can be controlled, and the aberration caused by the large-angle light entering through the second lens 2 can be reduced. At the same time, it is ensured that the combined lens formed by the second lens 2 and the third lens 3 is a positive lens, which suppresses the light, reduces the diameter of the rear port of the wide-angle lens, and realizes the miniaturization of the wide-angle lens.

[0047] In an exemplary embodiment, the wide-angle lens may also satisfy: -0.8≤F12 / F34≤0, where F12 is the combined focal length of the first lens 1 and the second lens 2, and F34 is the combined focal length of the third lens 3 and the fourth lens 4. By constraining the ratio of the combined focal length of the first lens 1 and the second lens 2 to the combined focal length of the third lens 3 and the fourth lens 4 within a reasonable range, the refractive power contribution of the front lens and the rear lens of the wide-angle lens can be reasonably allocated, which is conducive to correcting aberrations such as field curvature and distortion of the wide-angle lens, and improving the imaging quality of the wide-angle lens. At the same time, the total optical length of the wide-angle lens can be shortened, thereby realizing the miniaturization of the wide-angle lens.

[0048] In an exemplary embodiment, the wide-angle lens may also satisfy: 0.3≤∑CT / TTL≤0.6, where ∑CT is the sum of the center thickness of each lens on the optical axis from the first lens 1 to the fourth lens 4, and TTL is the total optical length of the wide-angle lens. Reasonable distribution of the center thickness of each lens on the optical axis can effectively shorten the total optical length of the wide-angle lens, and is beneficial to the structural design and production process of the wide-angle lens.

[0049] In an exemplary embodiment, the wide-angle lens also satisfies: 1≤ET1 / CT1≤3, where ET1 is the edge thickness of the first lens 1, and CT1 is the center thickness of the first lens 1 on the optical axis. Reasonable allocation of the edge thickness and center thickness of the first lens 1 can not only make the first lens 1 have good processability, but also make the light entering the system with a large field angle diverge, reduce the incident angle, make the light trend tend to be gentle, and reduce the difficulty of aberration correction.

[0050] In an exemplary embodiment, the wide-angle lens also satisfies: 0≤T12 / TTL≤0.3, where T12 is the air interval between the first lens 1 and the second lens 2 on the optical axis, and TTL is the total optical length of the wide-angle lens. By constraining the ratio of the air interval between the first lens 1 and the second lens 2 on the optical axis to the total optical length of the wide-angle lens within a reasonable range, the light can be smoothly transferred to the rear system, and sufficient space can be reserved for matching the structural setting.

[0051] In an exemplary embodiment, the wide-angle lens may also satisfy: 0.5≤ET2 / CT2≤1.2, where ET3 is the edge thickness of the third lens 3, and CT3 is the center thickness of the third lens 3 on the optical axis. Reasonable allocation of the edge thickness and center thickness of the third lens 3 can reduce the tolerance sensitivity of the third lens 3.

[0052] In an exemplary embodiment, the wide-angle lens may also satisfy: 0.1≤T23 / F23≤1, wherein T23 is the air interval between the second lens 2 and the third lens 3 on the optical axis, and F23 is the combined focal length of the second lens 2 and the third lens 3. By constraining the ratio of the air interval between the second lens 2 and the third lens 3 on the optical axis to the combined focal length of the second lens 2 and the third lens 3 within a reasonable range, the light can be smoothly transitioned from the image side surface of the second lens 2 to the object side surface of the third lens 3, thereby reducing the deflection angle of the marginal light deflected by the second lens 2 and the third lens 3, improving the imaging quality of the marginal field of view, and at the same time avoiding the reflection of the light between the second lens 2 and the third lens 3, reducing the risk of ghost image and stray light, and improving the imaging quality of the wide-angle lens.

[0053] In an exemplary embodiment, the wide-angle lens may also satisfy: 1≤(CT3+CT4) / T34≤5, where CT3 is the center thickness of the third lens 3 on the optical axis, CT4 is the center thickness of the fourth lens 4 on the optical axis, and T34 is the air interval on the optical axis between the third lens 3 and the fourth lens 4. By constraining the ratio of the sum of the center thicknesses of the third lens 3 and the fourth lens 4 to the air interval between the third lens 3 and the fourth lens 4 within a reasonable range, the astigmatism of the wide-angle lens can be controlled.

[0054] In an exemplary embodiment, the wide-angle lens may also satisfy: 3.5≤TTL / IH≤5, where TTL is the total optical length of the wide-angle lens, and IH is the maximum image height corresponding to the maximum field angle of the wide-angle lens. By constraining the ratio of the total optical length of the wide-angle lens to the maximum image height corresponding to the maximum field angle of the wide-angle lens within a reasonable range, the total optical length of the wide-angle lens can be effectively shortened while ensuring that the wide-angle lens has good imaging quality, thereby achieving miniaturization of the wide-angle lens.

[0055] In an exemplary embodiment, the wide-angle lens may also satisfy: 0.8≤BFL / F≤2, where BFL is the back focal length of the wide-angle lens, and F is the total effective focal length of the wide-angle lens. By constraining the ratio of the back focal length of the wide-angle lens to the total effective focal length of the wide-angle lens within a reasonable range, a balance can be achieved between the wide-angle lens having good imaging quality and the wide-angle lens having a back focal length that is easy to assemble, thereby reducing the difficulty of the assembly process of the wide-angle lens while ensuring the imaging quality of the wide-angle lens.

[0056] In an exemplary embodiment, the wide-angle lens may also satisfy: 4≤IH / ENPD≤5.5, where IH is the maximum image height corresponding to the maximum field angle of the wide-angle lens, and ENPD is the entrance pupil diameter of the wide-angle lens. By constraining the ratio of the maximum image height corresponding to the maximum field angle of the wide-angle lens to the entrance pupil diameter of the wide-angle lens within a reasonable range, the width of the light beam incident on the wide-angle lens can be increased, thereby improving the brightness of the image plane of the wide-angle lens while avoiding the generation of dark corners.

[0057] The technical solution of the present application adopts four lenses. By reasonably allocating the refractive power and surface shape of each lens and matching it with reasonable parameter settings, the wide-angle lens can be made suitable for high and low temperature environments (-40℃-80℃), and at least one of the beneficial effects of the wide-angle lens including high resolution, large field of view (120°), large NA (NA=about 0.35), telecentricity, large image surface (maximum image height IH≥10mm corresponding to the maximum field of view), small distortion (F-θ≤11%), and miniaturization can be achieved.

[0058] In an exemplary embodiment, at least one of the mirror surfaces of each lens in the first lens to the fourth lens is an aspherical mirror surface. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After adopting an aspherical lens, the aberration occurring during imaging can be eliminated as much as possible, thereby improving the imaging quality. Optionally, the object side surface of the first lens, the object side surface and the image side surface of the third lens and the fourth lens are all aspherical surfaces.

[0059] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the wide-angle lens can be changed to obtain the various results and advantages described in this specification.

[0060] Next, the four-piece high-NA near-infrared wide-angle telecentric high-resolution lens of the present invention is described in conjunction with the use and operation of a specific embodiment.

[0061] Example 1

[0062] The following reference Figure 1 A wide-angle lens according to Embodiment 1 of the present application is described. Figure 1 Schematic diagram of the structure of a wide-angle lens according to Example 1 of the present application.

[0063] like Figure 1 As shown, the wide-angle lens includes, in order from the object side to the image side along the optical axis: a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4. A stop STO5 may be disposed between the second lens 2 and the third lens 3.

[0064] The first lens 1 has negative refractive power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens 2 has negative refractive power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens 3 has positive refractive power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens 4 has positive refractive power, and its object side surface S7 is convex, and its image side surface S8 is convex. The light from the object passes through each surface S1 to S8 in sequence and is finally imaged on the imaging surface IMA.

[0065] Table 1 shows the basic parameters of the wide-angle lens of Example 1, wherein the units of the radius of curvature, thickness / distance and focal length are all millimeters (mm).

[0066] Table 1

[0067] In Example 1, the object side surface of the first lens, the object side surface and the image side surface of the third lens and the fourth lens are all aspherical surfaces, and the surface shape of each aspherical lens is x The following aspheric formulas can be used but are not limited to: ; in, x The aspheric surface is at a height of h When the position is , the distance vector height from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface, c =1 / R (i.e., paraxial curvature c is the inverse of the radius of curvature R in Table 1 above); k is the cone coefficient; BH is the correction coefficient of the i-th order aspheric surface. Table 2 gives the cone coefficients of the aspheric mirror surfaces S1-S8 that can be used in Example 1. k And the high-order coefficient A 2、 A 4、 A 6、 A 8、 A 10 .

[0068] Table 2

[0069] Table 3 shows the variation of back focus S8 parameters of the wide-angle lens of Example 1 under the multiple structures with temperature, wherein TEMP represents temperature.

[0070] Table 3

[0071] Example 2 The following reference Figure 2 A wide-angle lens according to Embodiment 2 of the present application is described. Figure 2Schematic diagram of the structure of a wide-angle lens according to Example 2 of the present application.

[0072] like Figure 2 As shown, the wide-angle lens includes, in order from the object side to the image side along the optical axis: a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4. A stop STO may be disposed between the second lens 2 and the third lens 3.

[0073] The first lens 1 has negative refractive power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens 2 has negative refractive power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens 3 has positive refractive power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens 4 has positive refractive power, and its object side surface S7 is convex, and its image side surface S8 is convex. The light from the object passes through each surface S1 to S8 in sequence and is finally imaged on the imaging surface IMA.

[0074] Table 4 shows the basic parameters of the wide-angle lens of Example 2, wherein the units of the radius of curvature, thickness / distance and focal length are all millimeters (mm).

[0075] Table 4

[0076] In Example 2, the object side surface of the first lens 1, the object side surface and the image side surface of the third lens 3 and the fourth lens 4 are all aspherical surfaces. Table 5 shows the cone coefficient k and the high-order coefficient A of each aspherical mirror surface S1-S8 that can be used in Example 2. 2、 A 4、 A 6、 A 8、 A 10 .

[0077] Table 5

[0078] Table 6 shows the variation of back focus S8 parameters of the wide-angle lens of Example 1 under the multiple structures with temperature, wherein TEMP represents temperature.

[0079] Table 6

[0080] Example 3 The following reference Figure 3 A wide-angle lens according to Example 3 of the present application is described. Figure 3 Schematic diagram of the structure of a wide-angle lens according to Example 3 of the present application.

[0081] like Figure 3As shown, the wide-angle lens includes, in order from the object side to the image side along the optical axis: a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4. A stop STO may be disposed between the second lens 2 and the third lens 3.

[0082] The first lens 1 has negative refractive power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens 2 has negative refractive power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens 3 has positive refractive power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens 4 has positive refractive power, and its object side surface S7 is convex, and its image side surface S8 is convex. The light from the object passes through each surface S1 to S8 in sequence and is finally imaged on the imaging surface IMA.

[0083] Table 7 shows the basic parameters of the wide-angle lens of Example 3, wherein the units of the radius of curvature, thickness / distance and focal length are all millimeters (mm).

[0084] Table 7

[0085] In Example 3, the object side surface of the first lens 1, the object side surface and the image side surface of the third lens 3 and the fourth lens 4 are all aspherical surfaces. Table 8 shows the cone coefficient k and the high-order coefficient A of each aspherical mirror surface S1-S8 that can be used in Example 3. 2、 A 4、 A 6、 A 8、 A 10 .

[0086] Table 8

[0087] Table 9 shows the variation of back focus S8 parameters of the wide-angle lens of Example 1 under the multiple structures with temperature, wherein TEMP represents temperature.

[0088] Table 9

[0089] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A four-element high-NA near-infrared wide-angle telecentric high-resolution lens, characterized in that: A first lens, a second lens, a third lens and a fourth lens are sequentially arranged with air spaces between them from the object side to the image side along the optical axis; The first lens has negative refractive power, the object side surface is convex, and the image side surface is concave; The second lens has negative refractive power, the object side surface is concave, and the image side surface is convex; The third lens has positive refractive power, the object side surface is convex, and the image side surface is concave; The fourth lens has positive refractive power, an object-side surface is convex, and an image-side surface is convex.

2. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens according to claim 1, characterized in that: The lens meets the following requirements: 26≤F2 / F≤10, where F2 is the effective focal length of the second lens and F is the total effective focal length of the wide-angle lens; -4≤F1 / F≤-1.7, where F1 is the effective focal length of the first lens; 2.5≤F3 / F≤4, where F3 is the effective focal length of the third lens.

3. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens according to claim 1 or 2, characterized in that: The lens meets the following requirements: -3≤D / F1≤-1, where D is the maximum optical aperture of the wide-angle lens and F1 is the effective focal length of the first lens; -1≤F4 / F1≤-2, wherein F4 is the effective focal length of the fourth lens, and F1 is the effective focal length of the first lens.

4. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens according to claim 1, characterized in that: The lens satisfies: -0.8≤(R21-R22) / (R21+R22)≤0.3, wherein R21 is the curvature radius of the object side surface of the second lens, and R22 is the curvature radius of the image side surface of the second lens.

5. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens according to claim 1, characterized in that: The lens meets the following requirements: 2≤F23 / F≤5, where F23 is the combined focal length of the second lens and the third lens; -0.8≤F12 / F34≤0, where F12 is the combined focal length of the first lens and the second lens, and F34 is the combined focal length of the third lens and the fourth lens; 0.1≤T23 / F23≤1, wherein T23 is the air distance between the second lens and the third lens on the optical axis, and F23 is the combined focal length of the second lens and the third lens.

6. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens according to claim 1, characterized in that: The lens meets the following requirements: 0.3≤∑CT / TTL≤0.6, where ∑CT is the sum of the center thicknesses of the first to fourth lenses on the optical axis, and TTL is the total optical length of the wide-angle lens; 0≤T12 / TTL≤0.3, wherein T12 is the air distance between the first lens and the second lens on the optical axis, and TTL is the total optical length of the wide-angle lens.

7. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens according to claim 1, characterized in that: The lens meets the following requirements: 1≤ET1 / CT1≤3, where ET1 is the edge thickness of the first lens, and CT1 is the center thickness of the first lens on the optical axis; 0.5≤ET3 / CT3≤1.2, wherein ET3 is the edge thickness of the third lens, and CT3 is the center thickness of the third lens on the optical axis; 1≤(CT3+CT4) / T34≤5, wherein CT3 is the center thickness of the third lens on the optical axis, CT4 is the center thickness of the fourth lens on the optical axis, and T34 is the air interval between the third lens and the fourth lens on the optical axis.

8. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens according to claim 1, characterized in that: The lens meets the following requirements: 3.5≤TTL / IH≤5, where TTL is the total optical length of the wide-angle lens, and IH is the maximum image height corresponding to the maximum field of view of the wide-angle lens; The lens satisfies: 4≤IH / ENPD≤5.5, wherein IH is the maximum image height corresponding to the maximum field angle of the wide-angle lens, and ENPD is the entrance pupil diameter of the wide-angle lens; 0.8≤BFL / F≤2, wherein BFL is the back focal length of the wide-angle lens, and F is the total effective focal length of the wide-angle lens.

9. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens according to claim 1, characterized in that: The image side surface of the fourth lens has at least one inflection point; And / or, an aperture is arranged between the second lens and the third lens.

10. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens according to claim 1, characterized in that: At least one of the object-side surface and the image-side surface of each of the first lens, the second lens, the third lens and the fourth lens is an aspherical mirror surface; The object side surface of the first lens, the object side surface and the image side surface of the third lens and the fourth lens are all aspherical mirror surfaces, and the surface shape x of each aspherical lens is expressed by the aspherical formula: ； In the formula, x is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c=1 / R, that is: the paraxial curvature c is the reciprocal of the curvature radius R; k is the cone coefficient; Ai is the coefficient of the higher-order term.

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