A four-piece high-NA near-infrared wide-angle telecentric high-resolution lens

Abstract

The present invention discloses a four-piece high-NA near-infrared wide-angle telecentric high-resolution lens, belonging to the technical field of optical imaging lens design. Along the optical axis, a first lens, a second lens, a third lens, and a fourth lens are arranged in sequence from the object side to the image side with air gaps therebetween; the first lens has a negative refractive power, the object side is convex, and the image side is concave; the second lens has a negative refractive power, the object side is concave, and the image side is convex; the third lens has a positive refractive power, the object side is convex, and the image side is concave; the fourth lens has a positive refractive power, the object side is convex, and the image side is convex. The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens provided by the present invention provides performance in complex environments by reasonably distributing the refractive powers and surface shapes of the respective lenses and collocating reasonable parameter settings, making the wide-angle lens widely applicable.

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] Due to the characteristics of a wide-angle lens having a large shooting range and being able to shoot more picture contents, wide-angle lenses can be applied to some fields with special requirements for the imaging range, such as action cameras, drones, vehicle-mounted imaging, and conference video equipment. With the increasing demand for wide-angle lenses in these fields, the requirements for the imaging quality of wide-angle lenses are getting higher and higher.

[0003] The application scenarios of wide-angle lenses in these fields are relatively extensive, and they can be used in complex environments such as severe vibration, high pressure, or high and low temperatures. Therefore, higher performance requirements are imposed on wide-angle lenses. Wide-angle lenses not only need to have good thermal stability to cope with variable usage environments such as high and low temperatures, but also need to have a small volume and weight, and be able to be paired with high-pixel chips to meet the applications in different usage scenarios. However, the performance of traditional wide-angle lenses is poor in the above complex environments and it is difficult to meet the usage 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 distributing the refractive power and surface shape of each lens and with reasonable parameter settings, the performance in complex environments is provided, making the wide-angle lens widely applicable.

[0005] To achieve the above purpose, the present invention is implemented by the following technical solutions:

[0006] The present invention provides a four-piece high-NA near-infrared wide-angle telecentric high-resolution lens, which is configured with a first lens, a second lens, a third lens, and a fourth lens having air gaps in sequence from the object side to the image side along the optical axis;

[0007] The first lens has a negative refractive power, the object side is a convex surface, and the image side is a concave surface;

[0008] The second lens has a negative refractive power, the object side is a concave surface, and the image side is a convex surface;

[0009] The third lens has a positive refractive power, the object side is a convex surface, and the image side is a concave surface;

[0010] The fourth lens has a positive refractive power, the object side is a convex surface, and the image side is a convex surface.

[0011] Further, the lens satisfies: 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.

[0012] Further, the lens satisfies: -4 ≤ F1 / F ≤ -1.7, where F1 is the effective focal length of the first lens.

[0013] Further, the lens satisfies: 2.5 ≤ F3 / F ≤ 4, where F3 is the effective focal length of the third lens.

[0014] Further, the lens satisfies: -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.

[0015] Further, the lens satisfies: -1 ≤ F4 / F1 ≤ -2, where F4 is the effective focal length of the fourth lens and F1 is the effective focal length of the first lens.

[0016] Further, the lens satisfies: -0.8 ≤ (R21 - R22) / (R21 + R22) ≤ 0.3, where R21 is the radius of curvature of the object side of the second lens and R22 is the radius of curvature of the image side of the second lens.

[0017] Further, the lens satisfies: 2 ≤ F23 / F ≤ 5, where F23 is the combined focal length of the second lens and the third lens.

[0018] Further, the lens also satisfies: -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.

[0019] Further, the lens satisfies: 0.1 ≤ T23 / F23 ≤ 1, where T23 is the air gap on the optical axis between the second lens and the third lens and F23 is the combined focal length of the second lens and the third lens.

[0020] Further, the lens satisfies: 0.3 ≤ ∑CT / TTL ≤ 0.6, where ∑CT is the sum of the central thicknesses 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.

[0021] Further, the lens satisfies: 0 ≤ T12 / TTL ≤ 0.3, where T12 is the air gap on the optical axis between the first lens and the second lens and TTL is the total optical length of the wide-angle lens.

[0022] Further, the lens satisfies: 1 ≤ ET1 / CT1 ≤ 3, where ET1 is the edge thickness of the first lens and CT1 is the central thickness of the first lens on the optical axis.

[0023] Further, the lens satisfies: 0.5 ≤ ET3 / CT3 ≤ 1.2, where ET3 is the edge thickness of the third lens and CT3 is the central thickness of the third lens on the optical axis.

[0024] Further, the lens satisfies: 1 ≤ (CT3 + CT4) / T34 ≤ 5, where CT3 is the central thickness of the third lens on the optical axis, CT4 is the central thickness of the fourth lens on the optical axis, and T34 is the air space between the third lens and the fourth lens on the optical axis.

[0025] Further, the lens satisfies: 3.5 ≤ TTL / IH ≤ 5, where TTL is the overall optical length of the wide-angle lens and IH is the maximum image height corresponding to the maximum field of view angle of the wide-angle lens.

[0026] Further, the lens satisfies: 4 ≤ IH / ENPD ≤ 5.5, where IH is the maximum image height corresponding to the maximum field of view angle of the wide-angle lens and ENPD is the entrance pupil diameter of the wide-angle lens.

[0027] Further, the lens also satisfies: 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.

[0028] Further, the image side of the fourth lens has at least one inflection point;

[0029] And / or, a diaphragm is disposed between the second lens and the third lens.

[0030] Further, at least one of the object sides and image sides of the first lens, the second lens, the third lens, and the fourth lens is an aspherical mirror surface.

[0031] Further, the object side of the first lens, the object sides and image sides of the third lens and the fourth lens are all aspherical mirror surfaces, and the surface profiles of the respective aspherical lenses x Are represented by the aspherical formula as:

[0032] ;

[0033] In the formula, x Is the distance sagitta from the vertex of the aspherical surface at the position where the height is 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 radius of curvature R; k is the conic coefficient; Ai Are the high-order term coefficients.

[0034] Advantages achieved by the present invention: The four-piece high-NA near-infrared wide-angle telecentric high-resolution lens provided by the present invention is configured with a first lens, a second lens, a third lens, and a fourth lens having air gaps in sequence from the object side to the image side along the optical axis. By reasonably distributing the refractive power and surface shape of each lens and matching reasonable parameter settings, the wide-angle lens can be applicable to high and low temperature environments (-40°C - 80°C), and achieve at least one of the beneficial effects of high resolution, large field of view (120°), large NA (NA = about 0.35), telecentric, large image plane (the maximum image height IH corresponding to the maximum field of view ≥ 10 mm), small distortion (F-θ ≤ 11%), and miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 FIG. shows a schematic structural diagram of a wide-angle lens according to Embodiment 1 of the present application.

[0036] Figure 2 FIG. shows a schematic structural diagram of a wide-angle lens according to Embodiment 2 of the present application.

[0037] Figure 3 FIG. shows a schematic structural diagram of a wide-angle lens according to Embodiment 3 of the present application.

[0038] In the figure:

[0039] 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Aperture STO; 6. Imaging plane IMA. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0041] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is 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 a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0042] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", and "coupled" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0043] As Figures 1 to 3 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. These four lenses are arranged in sequence along the optical axis from the object side to the image side. Among them, there may be an air gap between two adjacent lenses among the first lens 1 to the fourth lens 4.

[0044] 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 convex, and the image side surface may be concave. By setting the first lens 1 in the above structural form, it can be ensured that the incident angle of light on the object side surface of the first lens 1 is small, and the light can reach the subsequent system smoothly through the first lens 1, which is beneficial to realizing the large field of view angle of the wide-angle lens.

[0045] 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 concave, and the image side surface may be convex. By setting the second lens 2 as a negative lens, it can be ensured that the light path between the first lens 1 and the second lens 2 is stable, and the light emitted from the first lens 1 can be well received by the second lens 2, reducing the loss of light in each field of view and improving the relative illuminance of each field of view.

[0046] In an exemplary embodiment, the third lens 3 may have a 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 light while converging the light, so that the light path transitions smoothly.

[0047] 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 convex, and the image side surface may be convex. By setting the fourth lens 4 in the above structural form, it is beneficial to effectively transmit the light adjusted by each lens to the imaging surface, and further ensure that the wide-angle lens realizes the characteristic of a large image surface.

[0048] 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 beneficial to raise the light, so that the light transitions smoothly to the imaging surface to realize the large image surface of the telecentric wide-angle lens.

[0049] In an exemplary embodiment, the wide-angle lens may further include a diaphragm. The diaphragm may be disposed between the second lens 2 and the third lens 3.

[0050] In an exemplary embodiment, the wide-angle lens may further 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, large-angle light can be made to enter the system, thereby effectively increasing the field of view angle of the wide-angle lens.

[0051] In an exemplary embodiment, the wide-angle lens may further 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 angle of the wide-angle lens can be increased, and the wide-angle characteristic of the wide-angle lens can be achieved.

[0052] In an exemplary embodiment, the wide-angle lens may further 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. By configuring the radii of curvature of the object side surface and the image side surface of the second lens 2, large-angle field light can be effectively converged, and the aberration generated by the first lens 1 can be reduced, achieving high resolution of the wide-angle lens.

[0053] In an exemplary embodiment, the wide-angle lens may further 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 for the smooth transmission of light, and the aberration of the wide-angle lens can be effectively corrected, improving the imaging quality of the wide-angle lens.

[0054] In an exemplary embodiment, the wide-angle lens may further 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, the refractive power concentration of the wide-angle lens on the first lens 1 can be avoided, 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 first three front lenses, improving the imaging quality of the wide-angle lens.

[0055] In an exemplary embodiment, the wide-angle lens may further 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 path between the second lens 2 and the third lens 3 can be controlled, the aberration caused by the large-angle light entering through the second lens 2 can be reduced, and 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, the light is depressed, the rear aperture of the wide-angle lens is reduced, and the miniaturization of the wide-angle lens is achieved.

[0056] In an exemplary embodiment, the wide-angle lens may further 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 distributed, which is beneficial to correcting aberrations such as field curvature and distortion of the wide-angle lens, improving the imaging quality of the wide-angle lens, and at the same time, the optical total length of the wide-angle lens can be shortened, and the miniaturization of the wide-angle lens is achieved.

[0057] In an exemplary embodiment, the wide-angle lens may further satisfy: 0.3 ≤ ∑CT / TTL ≤ 0.6, where ∑CT is the sum of the central thicknesses of the lenses on the optical axis from the first lens 1 to the fourth lens 4, and TTL is the optical total length of the wide-angle lens. By reasonably distributing the central thicknesses of the lenses on the optical axis, the optical total length of the wide-angle lens can be effectively shortened, and at the same time, it is beneficial to the structural design and production process of the wide-angle lens.

[0058] In an exemplary embodiment, the wide-angle lens further satisfies: 1 ≤ ET1 / CT1 ≤ 3, where ET1 is the edge thickness of the first lens 1, and CT1 is the central thickness of the first lens 1 on the optical axis. By reasonably distributing the edge thickness and the central thickness of the first lens 1, the first lens 1 can have good processability, and at the same time, the light entering the large field of view angle of the system can be diverged, the incident angle can be reduced, the light path can be made to tend to be gentle, and the difficulty of aberration correction can be reduced.

[0059] In an exemplary embodiment, the wide-angle lens further satisfies: 0 ≤ T12 / TTL ≤ 0.3, where T12 is the air gap between the first lens 1 and the second lens 2 on the optical axis, and TTL is the optical total length of the wide-angle lens. By constraining the ratio of the air gap between the first lens 1 and the second lens 2 on the optical axis to the optical total length of the wide-angle lens within a reasonable range, the light can be smoothly transitioned to the rear system, and at the same time, enough space can be reserved for matching the structural setting.

[0060] In an exemplary embodiment, the wide-angle lens may further satisfy: 0.5 ≤ ET2 / CT2 ≤ 1.2, where ET3 is the edge thickness of the third lens 3, and CT3 is the central thickness of the third lens 3 on the optical axis. Reasonably allocating the edge thickness and the central thickness of the third lens 3 can reduce the tolerance sensitivity of the third lens 3.

[0061] In an exemplary embodiment, the wide-angle lens may further satisfy: 0.1 ≤ T23 / F23 ≤ 1, where T23 is the air gap 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 gap 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 smoothly transition 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 rays deflected by the second lens 2 and the third lens 3, improving the imaging quality of the marginal field of view. At the same time, it can also avoid the reflection of light between the second lens 2 and the third lens 3, reduce the risk of ghost image and stray light generation, and improve the imaging quality of the wide-angle lens.

[0062] In an exemplary embodiment, the wide-angle lens may further satisfy: 1 ≤ (CT3 + CT4) / T34 ≤ 5, where CT3 is the central thickness of the third lens 3 on the optical axis, CT4 is the central thickness of the fourth lens 4 on the optical axis, and T34 is the air gap between the third lens 3 and the fourth lens 4 on the optical axis. By constraining the ratio of the sum of the central thicknesses of the third lens 3 and the fourth lens 4 to the air gap between the third lens 3 and the fourth lens 4 within a reasonable range, the astigmatism of the wide-angle lens can be controlled.

[0063] In an exemplary embodiment, the wide-angle lens may further satisfy: 3.5 ≤ TTL / IH ≤ 5, where TTL is the overall optical length of the wide-angle lens, and IH is the maximum image height corresponding to the maximum field of view angle of the wide-angle lens. By constraining the ratio of the overall optical length of the wide-angle lens to the maximum image height corresponding to the maximum field of view angle of the wide-angle lens within a reasonable range, it is possible to effectively shorten the overall optical length of the wide-angle lens while ensuring good imaging quality of the wide-angle lens, thereby realizing the miniaturization of the wide-angle lens.

[0064] In an exemplary embodiment, the wide-angle lens may further 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 good imaging quality of the wide-angle lens and an easily assembled back focal length, while ensuring the imaging quality of the wide-angle lens, reducing the assembly process difficulty of the wide-angle lens.

[0065] In an exemplary embodiment, the wide-angle lens may further satisfy: 4 ≤ IH / ENPD ≤ 5.5, where IH is the maximum image height corresponding to the maximum field of view 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 of view 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 avoiding the generation of vignetting while improving the image plane brightness of the wide-angle lens.

[0066] In the technical solution of the present application, four lenses are adopted. By reasonably distributing the refractive power and surface shape of each lens and matching reasonable parameter settings, the wide-angle lens can be applicable to high and low temperature environments (-40°C - 80°C), and achieve at least one beneficial effect among high resolution, large field of view angle (120°), large NA (NA ≈ 0.35), telecentricity, large image plane (the maximum image height IH corresponding to the maximum field of view angle ≥ 10 mm), small distortion (F-θ ≤ 11%), and miniaturization.

[0067] In an exemplary embodiment, at least one of the lens surfaces of each of the first lens to the fourth lens is an aspherical lens surface. The characteristic of an aspherical lens is that the curvature continuously changes from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging 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.

[0068] 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.

[0069] Next, the four-piece high-NA near-infrared wide-angle telecentric high-resolution lens of the present invention will be described in combination with the usage operations of specific embodiments.

[0070] Embodiment 1

[0071] The following refers to Figure 1 Describe the wide-angle lens according to Embodiment 1 of the present application. Figure 1 It is a schematic structural diagram of the wide-angle lens according to Embodiment 1 of the present application.

[0072] As Figure 1 shown, the wide-angle lens sequentially includes, 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. The aperture stop STO5 can be disposed between the second lens 2 and the third lens 3.

[0073] The first lens 1 has a negative refractive power, with its object side S1 being convex and its image side S2 being concave. The second lens 2 has a negative refractive power, with its object side S3 being concave and its image side S4 being convex. The third lens 3 has a positive refractive power, with its object side S5 being convex and its image side S6 being concave. The fourth lens 4 has a positive refractive power, with its object side S7 being convex and its image side S8 being convex. Light from the object sequentially passes through each surface S1 to S8 and finally forms an image on the imaging surface IMA.

[0074] Table 1 shows the basic parameter table of the wide-angle lens of Example 1, where the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0075] Table 1

[0076]

[0077] In Example 1, the object side of the first lens, the object side and the image side of the third lens and the fourth lens are all aspherical surfaces, and the surface profiles of each aspherical lens x can be defined by, but not limited to, the following aspherical formula:

[0078] ;

[0079] where x is the sagitta, the distance from the vertex of the aspherical surface to the aspherical surface along the optical axis at a position with a height of h ; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; BH is the correction coefficient of the i-th order of the aspherical surface. Table 2 gives the conic coefficients k and the high-order term coefficients A 2、 A 4、 A 6、 A 8、 A 10 .

[0080] Table 2

[0081]

[0082] Table 3 shows the table of the change of the back focal length S8 parameter of the wide-angle lens of Example 1 under the multi-structure with temperature, where TEMP represents temperature.

[0083] Table 3

[0084]

[0085] Example 2

[0086] The following refers to Figure 2 a wide-angle lens according to Embodiment 2 of the present application. Figure 2 It is a schematic structural diagram of the wide-angle lens according to Embodiment 2 of the present application.

[0087] As Figure 2 shown, the wide-angle lens sequentially includes, 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. The aperture stop STO can be disposed between the second lens 2 and the third lens 3.

[0088] The first lens 1 has a negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave. The second lens 2 has a negative refractive power, its object side surface S3 is concave, and its image side surface S4 is convex. The third lens 3 has a positive refractive power, its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens 4 has a positive refractive power, its object side surface S7 is convex, and its image side surface S8 is convex. The light from the object sequentially passes through the surfaces S1 to S8 and finally forms an image on the imaging surface IMA.

[0089] Table 4 shows the basic parameter table of the wide-angle lens of Embodiment 2, where the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0090] Table 4

[0091]

[0092] In Embodiment 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 conic coefficient k and the higher-order term coefficient A that can be used for each aspherical mirror surface S1-S8 in Embodiment 2 2、 A 4、 A 6、 A 8、 A 10 .

[0093] Table 5

[0094]

[0095] Table 6 shows the table of the change of the back focal S8 parameter with temperature under the multi-structure of the wide-angle lens of Embodiment 1, where TEMP represents temperature.

[0096] Table 6

[0097]

[0098] Embodiment 3

[0099] The following refers to Figure 3 a wide-angle lens according to Embodiment 3 of the present application. Figure 3Schematic structural diagram of a wide-angle lens according to Embodiment 3 of the present application.

[0100] As Figure 3 shown, the wide-angle lens sequentially includes, 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. The aperture stop STO can be disposed between the second lens 2 and the third lens 3.

[0101] The first lens 1 has a negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave. The second lens 2 has a negative refractive power, its object side surface S3 is concave, and its image side surface S4 is convex. The third lens 3 has a positive refractive power, its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens 4 has a positive refractive power, its object side surface S7 is convex, and its image side surface S8 is convex. Light from the object sequentially passes through the surfaces S1 to S8 and finally forms an image on the imaging surface IMA.

[0102] Table 7 shows the basic parameter table of the wide-angle lens of Embodiment 3, where the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm).

[0103] Table 7

[0104]

[0105] In Embodiment 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 conic coefficient k and the higher-order term coefficient A that can be used for the aspherical mirror surfaces S1-S8 of Embodiment 3 2、 A 4、 A 6、 A 8、 A 10 .

[0106] Table 8

[0107]

[0108] Table 9 shows the table of the change of the back focal S8 parameter with temperature under the multiple structures of the wide-angle lens of Embodiment 1, where TEMP represents temperature.

[0109] Table 9

[0110]

[0111] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can still be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

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

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: -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.

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 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 reciprocal of the curvature radius R; k is the cone coefficient; Ai is the coefficient of the higher-order term.

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