Small-sized single-infrared wide-angle optical imaging system and camera module applied by same

Abstract

The utility model provides a miniature single-infrared wide-angle optical imaging system and a camera module applying the same, comprising a first lens and a second lens, the first lens has negative focal power, the object side surface of the first lens is a concave surface, the image side surface of the first lens is a concave surface, the second lens has positive focal power, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface. The optical imaging system satisfies the following relation: 92 < DFOV / (DT11 * ImgD * TTL) < 132; by adopting the combination of the two plastic lenses, the large wide-angle range is realized, the resolving power of the lens is also considered, the object detail information can be better captured, the object detail capturing capability of the optical lens can be improved, the optical lens has the advantages of high pixel, large wide angle and small caliber, the structure is compact, the processing and the installation are convenient, and meanwhile, the optical lens is convenient to use. The configuration of the large aperture can increase the light incoming amount of the optical system and improve the imaging quality, so as to meet the requirements of people for large-wide-angle high-definition imaging in industrial production and manufacturing.

Description

Technical Field

[0001] The present application relates to the field of optical imaging, and in particular to a small single infrared large-angle optical imaging system and a camera module used therein. Background Art

[0002] In recent years, the rapid progress of artificial intelligence technology has driven the industry to gradually transition towards unmanned intelligence. In daily industrial production and manufacturing, people are increasingly accustomed to relying on the power of intelligent machines to help people improve the efficiency and speed of production and manufacturing. Among them, the detection and monitoring system based on machine vision has become a key part of improving the speed and efficiency of industrial production and manufacturing, and image acquisition through the lens is undoubtedly one of the prerequisites for realizing machine vision.

[0003] However, since industrial lenses are mainly used in very complex production environments, the requirements for the cameras they carry are extremely high, requiring not only a large field of view, but also good imaging performance. At present, most industrial lenses on the market generally use multiple lenses made of glass and plastic materials in order to pursue wide angles and good imaging performance. This will result in a large lens size, high cost, and is not conducive to market promotion and application. In addition, with the increasing miniaturization of optoelectronic components and strong light interference during the production process, the market is in urgent need of manufacturing a small, large field of view, and low-cost single infrared optical imaging lens. Utility Model Content

[0004] In order to solve the problems of existing industrial lenses such as large size, high cost and general imaging, the utility model provides a small single infrared wide-angle optical imaging system and a camera module used therein. By adopting a combination of two plastic lenses, a wide-angle range is achieved while taking into account the resolution capability of the lens, so that it can better capture the detailed information of the object, and at the same time, it can also improve the ability of the optical lens to capture the details of the photographed object, so as to meet people's needs for wide-angle and high-definition imaging in industrial production and manufacturing.

[0005] The technical solution adopted in this application is:

[0006] A small single infrared large-angle optical imaging system includes a first lens and a second lens in sequence from an object plane to an image plane along an optical axis;

[0007] The first lens has negative optical power, its object side surface is concave, and its image side surface is concave;

[0008] The second lens has positive refractive power, an object-side surface thereof is concave, and an image-side surface thereof is convex.

[0009] Preferably, the optical imaging system satisfies the following relationship:

[0010] 92<DFOV / (DT11*ImgD*TTL)<132;

[0011] Wherein, DFOV is the maximum field of view of the optical imaging system, DT11 is the maximum effective light transmission semi-aperture of the object side of the first lens, TTL is the axial distance from the object side of the first lens to the imaging surface, and ImgD is half of the diagonal length of the effective pixel area on the imaging surface.

[0012] Preferably, the optical imaging system satisfies the following relationship:

[0013] 2.6<f*tan(DFVO) / T12<4.5;

[0014] Wherein, f is the effective focal length of the optical imaging system, and T12 is the distance between the first lens and the second lens.

[0015] Preferably, the optical imaging system satisfies the following relationship:

[0016] 4.7<(f1-f2) / (f1+f2)<9.2;

[0017] 1.8<f2 / (f1-f2)<4.1;

[0018] 1.6<f1 / f12<2.5;

[0019] Wherein, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, and f12 is the combined focal length of the first lens and the second lens.

[0020] Preferably, the optical imaging system satisfies the following relationship:

[0021] 5.9<TTL / f<7.6;

[0022] Wherein, TTL is the total length of the optical imaging system, and f is the effective focal length of the optical imaging system.

[0023] Preferably, the optical imaging system satisfies the following relationship:

[0024] 2.6<TTL / (CT1+CT2)<3.5;

[0025] Wherein, TTL is the total length of the optical imaging system, CT1 is the center thickness of the first lens, and CT2 is the center thickness of the second lens.

[0026] Preferably, the optical imaging system satisfies the following relationship:

[0027] 0.3<|(R2-R1) / (R4-R3)|<1.5;

[0028] Among them, R1 is the curvature radius of the object side of the first lens, R2 is the curvature radius of the image side of the first lens, R3 is the curvature radius of the object side of the second lens, and R4 is the curvature radius of the image side of the second lens.

[0029] Preferably, the optical imaging system satisfies the following relationship:

[0030] 0.7<DT12 / CT2<1.3;

[0031] Wherein, DT12 is the maximum effective semi-aperture of the first lens on the image side, and CT2 is the center thickness of the second lens on the optical axis.

[0032] Preferably, the maximum effective light transmission semi-aperture of the object side of the first lens is ≤1.11 mm.

[0033] Preferably, both the first lens and the second lens are aspherical plastic lenses.

[0034] Preferably, the total length of the lens of the optical imaging system is ≤2.7 mm, the full field angle is >157°, and the F number is ≤3.3.

[0035] On the other hand, an embodiment of the present application further provides a camera module, which at least includes an optical lens, in which the above-mentioned small single infrared large-angle optical imaging system is installed.

[0036] Compared with the prior art, the beneficial effects of this application are as follows:

[0037] The utility model provides a small single infrared wide-angle optical imaging system and a camera module used therein. By adopting a combination of two plastic lenses, a wide-angle range is achieved while taking into account the resolution capability of the lens, so that the system can better capture the detailed information of the object, and at the same time, the optical lens can also improve the ability to capture the details of the photographed object. The system has the advantages of high pixel, wide angle and small aperture, compact structure, and is easy to process and install. At the same time, the configuration of a large aperture can increase the amount of light entering the optical system and higher imaging quality, so as to meet people's needs for wide-angle high-definition imaging in industrial production and manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for describing the embodiments are briefly introduced below.

[0039] Figure 1 It is a structural schematic diagram of an optical imaging system or camera module according to Embodiment 1 of the present application;

[0040] Figure 2 The MTF curve and MTF defocus curve of the optical imaging system or camera module in Example 1 of the present application;

[0041] Figure 3 It is a structural schematic diagram of an optical imaging system or camera module according to Embodiment 2 of the present application;

[0042] Figure 4 It is the MTF curve and MTF defocus curve of the optical imaging system or camera module of Example 2 of the present application;

[0043] Figure 5 It is a structural schematic diagram of an optical imaging system or camera module according to Embodiment 3 of the present application;

[0044] Figure 6 The MTF curve and MTF defocus curve of the optical imaging system or camera module of Example 3 of the present application;

[0045] Figure 7 It is a structural schematic diagram of an optical imaging system or camera module according to Embodiment 4 of the present application;

[0046] Figure 8 These are the MTF curve and MTF defocus curve of the optical imaging system or camera module of Example 4 of the present application. DETAILED DESCRIPTION

[0047] A small single infrared large-angle optical imaging system, which is composed of a first lens E1, an aperture ATO, a second lens E2, and an infrared filter E3 in sequence from the object plane to the image plane along the optical axis;

[0048] The first lens has negative optical power, its object side surface is concave, and its image side surface is concave;

[0049] The second lens has positive refractive power, an object-side surface thereof is concave, and an image-side surface thereof is convex.

[0050] The embodiment of the utility model discloses a small single infrared wide-angle optical imaging system, which is mainly used in the industrial field. By adopting a combination of two plastic lenses, a wide-angle range is achieved while taking into account the resolution ability of the lens, so that it can better capture the detailed information of the object, and at the same time, it can also improve the ability of the optical lens to capture the details of the photographed object, so as to meet people's needs for wide-angle high-definition imaging in industrial production and manufacturing.

[0051] Furthermore, the optical imaging system satisfies the following relationship:

[0052] 92<DFOV / (DT11*ImgD*TTL)<132;

[0053] Among them, DFOV is the maximum field of view of the optical imaging system, DT11 is the maximum effective semi-aperture of the first lens object side, TTL is the axial distance from the first lens object side to the imaging surface, and ImgD is half of the diagonal length of the effective pixel area on the imaging surface. This relationship reflects the constraints of the optical lens on the field of view and thinness, so that the optical system has good thinness while meeting the wide-angle requirements, ensuring that the optical system has the characteristics of ultra-wide angle, miniaturization, and thinness. When it is lower than the lower limit of the relationship, on the basis of ensuring that the field of view of the optical lens is ultra-wide angle, DT11*TTL*IamgD further increases, which will over-compress the thinness of the optical lens and is not conducive to the improvement of the performance of the optical lens; when it exceeds the upper limit of the relationship, it is difficult for the optical lens to obtain good imaging resolution.

[0054] Furthermore, the optical imaging system satisfies the following relationship:

[0055] 2.6<f*tan(DFVO) / T12<4.5;

[0056] Among them, f is the effective focal length of the optical imaging system, and T12 is the distance between the first lens and the second lens. This relationship reflects the constraints of the field of view angle of the optical lens and the lens spacing, which will enable the optical system to meet the wide-angle requirements while also having the characteristics of a small optical focal length, ensuring that the lens has the characteristics of ultra-wide angle and miniaturization. When it is higher or lower than the upper and lower limits of the relationship, while ensuring that the field of view angle of the optical lens is ultra-wide angle, T12 will be further reduced, which will over-compress the thickness of the optical lens and the air space between the lenses, which is not conducive to the processing of the lens, and will also make the imaging resolution of the optical lens worse.

[0057] Furthermore, the single infrared industrial optical imaging satisfies the following relationship:

[0058] 4.7<(f1-f2) / (f1+f2)<9.2;

[0059] Among them, f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. By adjusting the optical power of the first lens and the second lens, it is possible to avoid the optical power being too concentrated on the second lens, and at the same time, it is helpful to constrain the image side of the first lens and the surface shape of the second lens, and avoid excessive bending that affects the processing technology of the first lens and the second lens. In addition, satisfying the above relationship can also reduce the tolerance sensitivity of the optical lens. When the lower limit of the above relationship is exceeded, the optical power of the first lens is too concentrated, resulting in the surface shape of the image side of the second lens being too curved, which is not conducive to the processing technology of the first lens. When the upper limit of the above relationship is exceeded, the optical power of the first lens is insufficient, which is not conducive to the correction of the aberration of the optical lens and affects the tolerance sensitivity of the optical lens.

[0060] Furthermore, the single infrared industrial optical imaging satisfies the following relationship:

[0061] 1.8<f2 / (f1-f2)<4.1;

[0062] Among them, f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. By reasonably allocating the ratio of the focal power of the first and second optical lenses close to the image plane within a reasonable range, the residual spherical aberration after balancing can be used to balance the aberration, and then the aberration of the system can be fine-tuned and controlled, and the precise control of the on-axis field aberration can be strengthened.

[0063] Furthermore, the single infrared industrial optical imaging satisfies the following relationship:

[0064] 1.6<f1 / f12<2.5;

[0065] Among them, f1 is the effective focal length of the first lens, and f12 is the effective combined focal length of the first and second lenses. By constraining the ratio of the focal length of the first lens to the effective focal length of the first and second lenses combined, the optical power of the first lens and the second lens can be properly distributed, allowing the second lens to have more diverse coordination, thereby achieving a balance of the internal aberrations of the optical lens on the basis of satisfying the miniaturization design of the optical lens, thereby helping to adjust the field curvature of the imaging edge of the optical lens, while reducing the distortion of the optical lens and improving the resolution quality of the optical lens.

[0066] Furthermore, the single infrared industrial optical imaging satisfies the following relationship:

[0067] 5.9<TTL / f<7.6;

[0068] Wherein, TTL is the total length of the imaging lens, and f is the effective optical focal length of the imaging lens. By constraining the ratio of the total length of the imaging lens to the optical focal length of the imaging lens, the distance between the first lens and the second lens can be reasonably set, and the phenomenon that the incident light beam diverges and expands greatly after passing through the first lens can be effectively suppressed without excessively strengthening the convergence effect of the lens group on the image side of the second lens, thereby preventing the system from generating large aberrations, and effectively limiting the length of the optical lens, which is conducive to miniaturization of the optical lens.

[0069] Furthermore, the single infrared industrial optical imaging satisfies the following relationship:

[0070] 2.6<TTL / (CT1+CT2)<3.5;

[0071] Wherein, TTL is the total length of the imaging lens, CT1 is the center thickness of the first lens, and CT2 is the center thickness of the second lens. By constraining the ratio of the total length of the imaging lens to the sum of the center thicknesses of each lens of the imaging lens, the overall length of the optical lens can be effectively constrained to meet the miniaturization requirements.

[0072] Furthermore, the single infrared industrial optical imaging satisfies the following relationship:

[0073] 0.3<|(R2-R1) / (R4-R3)|<1.5;

[0074] Among them, R1 is the radius of curvature of the object side of the first lens, R2 is the radius of curvature of the image side of the first lens, R3 is the radius of curvature of the object side of the second lens, and R4 is the radius of curvature of the image side of the second lens. By controlling the ratio of the difference in the radius of curvature between the image side and the object side of the first lens to the difference in the radius of curvature between the image side and the object side of the second lens, the total deflection angle of the object side and the image side of the first lens at the edge of the field of view can be reasonably controlled within a reasonable range, which can effectively reduce the sensitivity of the system and improve the lens yield. At the same time, it is conducive to reasonably controlling the curvature degree of the second lens, so that it has better processing and molding characteristics, and at the same time avoids excessive deflection of light when transmitting between lenses, reducing the processing difficulty of the optical lens group.

[0075] Furthermore, the single infrared industrial optical imaging satisfies the following relationship:

[0076] 0.7<DT12 / CT2<1.3;

[0077] Among them, DT12 is the maximum effective semi-aperture of the image side of the first lens, and CT2 is the center thickness of the second lens on the optical axis. When the above conditional formula is met, since the effective semi-aperture of the lens and the thickness of the lens itself affect each other, by reasonably controlling the size of the effective semi-aperture of the image side of the first lens, the center thickness of the second lens on the optical axis can be reasonably shortened, and the volume of the overall lens group can be compressed to a greater extent, which is conducive to reducing the total optical length of the optical system and reducing the risk of ghost images; exceeding the upper limit of the relationship is not conducive to reducing the effective semi-aperture of the image side of the first lens, affecting the smooth incidence of light on the second lens, and increasing the risk of ghost images. Below the lower limit of the relationship, the outer diameter of the first lens barrel is too small, which will also cause the wall thickness of the lens barrel to be too thin, seriously affecting the strength and quality of the lens. If the outer diameter of the first lens barrel is greater than 4.5mm, the area of ​​the end cannot be reduced well, which has an adverse effect on reducing the screen-to-body ratio.

[0078] Furthermore, the maximum effective semi-aperture of the first lens object side is ≤1.11mm, the total lens length of the optical imaging system is ≤2.7mm, the full field angle is >157°, and the F number is ≤3.3. The single infrared wide-angle industrial optical imaging lens configured in the utility model has the advantages of high pixel, wide angle and small aperture, compact structure, easy processing and installation, and at the same time, the configuration of large aperture can increase the amount of light entering the optical system and higher imaging quality.

[0079] In the four cases described, the first lens and the second lens are both aspherical plastic lenses. The utility model embodiment discloses a single infrared large-angle industrial optical lens, which realizes a wide-angle range while taking into account the resolution ability of the lens by using a combination of two plastic lenses, so that it can better capture the detailed information of the object, and at the same time improve the ability of the optical lens to capture the details of the photographed object, so as to meet people's needs for wide-angle high-definition imaging in industrial production.

[0080] Embodiment 1

[0081] Specifically, as a preferred embodiment of the present invention but not limiting, the following reference is made to Figure 1 to Figure 2 An optical imaging lens according to Embodiment 1 of the present application is described. Figure 1 A schematic structural diagram of an optical imaging lens according to Embodiment 1 of the present application is shown.

[0082] like Figure 1 As shown, the optical imaging lens according to an exemplary embodiment of the present application includes, in order from the object side to the image side along the optical axis: a first lens E1, an aperture surface STO, a second lens E2, an infrared filter E3, a chip protection glass E4 and an imaging surface S9.

[0083] The first lens E1 has negative power, and its object side surface S1 is concave, and its image side surface S2 is concave. The second lens E2 has positive power, and its object side surface S3 is concave, and its image side surface S4 is convex. The filter E3 has an object side surface S5 and an image side surface S6. The chip protection glass E4 has an object side surface S7 and an image side surface S8. The light from the object passes through surfaces S1 to S8 in sequence and is finally imaged on the imaging surface S9.

[0084] Table 1 shows the surface type, curvature radius, thickness and material of each lens of the optical imaging lens of Example 1, wherein the units of the curvature radius and thickness are both millimeters (mm).

[0085] Table 1: Basic parameters of the optical imaging system of Example 1

[0086]

[0087] In Table 1, the object side surface and the image side surface of any lens of the first lens E1 and the second lens E2 are both Q-type aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical formula:

[0088]

[0089] Wherein, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, K is the cone coefficient, Am is the aspherical coefficient, rmax is the maximum radial radius coordinate, and u=r / rmax. Table 2 shows the cone coefficients and high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of each aspherical surface that can be used in Example 1.

[0090] Table 2: Aspheric surface related values ​​of the lens surface of Example 1

[0091]

[0092] Figure 2 The MTF curve and MTF defocus curve of the optical imaging lens of Example 1 are shown. The MTF curve represents the MTF values ​​in the meridian and sagittal directions of different fields of view at different spatial frequencies. The MTF defocus curve represents the MTF separation in the meridian and sagittal directions of different fields of view at different spatial frequencies. The lower the MTF separation in the meridian and sagittal directions, the better the imaging quality of the optical imaging lens. It can be seen from the figure that the optical imaging lens given in Example 1 can achieve good imaging quality.

[0093] Embodiment 2

[0094] Specifically, as a preferred embodiment of the present invention but not limiting, the following reference is made to Figure 3 to Figure 4 An optical imaging lens according to Embodiment 2 of the present application is described. Figure 3 A schematic structural diagram of an optical imaging lens according to Embodiment 2 of the present application is shown.

[0095] like Figure 3 As shown, the optical imaging lens according to an exemplary embodiment of the present application includes, in order from the object side to the image side along the optical axis: a first lens E1, an aperture surface STO, a second lens E2, an infrared filter E3, a chip protection glass E4 and an imaging surface S9.

[0096] The first lens E1 has negative power, and its object side surface S1 is concave, and its image side surface S2 is concave. The second lens E2 has positive power, and its object side surface S3 is concave, and its image side surface S4 is convex. The filter E3 has an object side surface S5 and an image side surface S6. The chip protection glass E4 has an object side surface S7 and an image side surface S8. The light from the object passes through surfaces S1 to S8 in sequence and is finally imaged on the imaging surface S9.

[0097] Table 3 shows the surface type, curvature radius, thickness and material of each lens of the optical imaging lens of Example 2, wherein the units of the curvature radius and thickness are both millimeters (mm).

[0098] Table 3: Basic parameters of the optical imaging system of Example 2

[0099]

[0100] In Table 3, the object side surface and the image side surface of any lens of the first lens E1 and the second lens E2 are both Q-type aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical formula:

[0101]

[0102] Wherein, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, K is the cone coefficient, Am is the aspherical coefficient, rmax is the maximum radial radius coordinate, and u=r / rmax. Table 4 shows the cone coefficients and high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of each aspherical surface that can be used in Example 2.

[0103] Table 4: Aspheric surface related values ​​of lens surface in Example 2

[0104]

[0105] Figure 4 The MTF curve and MTF defocus curve of the optical imaging lens of Example 2 are shown. The MTF curve represents the MTF values ​​in the meridian and sagittal directions of different fields of view at different spatial frequencies. The MTF defocus curve represents the MTF separation in the meridian and sagittal directions of different fields of view at different spatial frequencies. The lower the MTF separation in the meridian and sagittal directions, the better the imaging quality of the optical imaging lens. It can be seen from the figure that the optical imaging lens given in Example 2 can achieve good imaging quality.

[0106] Embodiment 3

[0107] Specifically, as a preferred embodiment of the present invention but not limiting, the following reference is made to Figures 5 and 6 An optical imaging lens according to Embodiment 3 of the present application is described. Figure 5 A schematic structural diagram of an optical imaging lens according to Embodiment 3 of the present application is shown.

[0108] like Figure 5 As shown, the optical imaging lens according to an exemplary embodiment of the present application includes, in order from the object side to the image side along the optical axis: a first lens E1, an aperture surface STO, a second lens E2, an infrared filter E3, a chip protection glass E4 and an imaging surface S9.

[0109] The first lens E1 has negative power, and its object side surface S1 is concave, and its image side surface S2 is concave. The second lens E2 has positive power, and its object side surface S3 is concave, and its image side surface S4 is convex. The filter E3 has an object side surface S5 and an image side surface S6. The chip protection glass E4 has an object side surface S7 and an image side surface S8. The light from the object passes through surfaces S1 to S8 in sequence and is finally imaged on the imaging surface S9.

[0110] Table 5 shows the surface type, curvature radius, thickness and material of each lens of the optical imaging lens of Example 3, wherein the units of the curvature radius and thickness are both millimeters (mm).

[0111] Table 5: Basic parameters of the optical imaging system of Example 3

[0112]

[0113] In Table 5, the object side surface and the image side surface of any lens of the first lens E1 and the second lens E2 are both Q-type aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical formula:

[0114]

[0115] Wherein, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, K is the cone coefficient, Am is the aspherical coefficient, rmax is the maximum radial radius coordinate, and u=r / rmax. Table 6 shows the cone coefficients and high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of each aspherical surface that can be used in Example 3.

[0116] Table 6: Aspheric surface related values ​​of lens surface in Example 3

[0117]

[0118] Figure 6 The MTF curve and MTF defocus curve of the optical imaging lens of Example 3 are shown. The MTF curve represents the MTF values ​​in the meridian and sagittal directions of different fields of view at different spatial frequencies. The MTF defocus curve represents the MTF separation in the meridian and sagittal directions of different fields of view at different spatial frequencies. The lower the MTF separation in the meridian and sagittal directions, the better the imaging quality of the optical imaging lens. It can be seen from the figure that the optical imaging lens given in Example 3 can achieve good imaging quality.

[0119] Embodiment 4:

[0120] Specifically, as a preferred embodiment of the present invention but not limiting, the following reference is made to Figures 7 and 8 An optical imaging lens according to Embodiment 4 of the present application is described. Figure 7 A schematic structural diagram of an optical imaging lens according to Embodiment 4 of the present application is shown.

[0121] like Figure 7 As shown, the optical imaging lens according to an exemplary embodiment of the present application includes, in order from the object side to the image side along the optical axis: a first lens E1, an aperture surface STO, a second lens E2, an infrared filter E3, a chip protection glass E4 and an imaging surface S9.

[0122] The first lens E1 has negative power, and its object side surface S1 is concave, and its image side surface S2 is concave. The second lens E2 has positive power, and its object side surface S3 is concave, and its image side surface S4 is convex. The filter E3 has an object side surface S5 and an image side surface S6. The chip protection glass E4 has an object side surface S7 and an image side surface S8. The light from the object passes through surfaces S1 to S8 in sequence and is finally imaged on the imaging surface S9.

[0123] Table 7 shows the surface type, curvature radius, thickness and material of each lens of the optical imaging lens of Example 4, wherein the units of the curvature radius and thickness are both millimeters (mm).

[0124] Table 7: Basic parameters of the optical imaging system of Example 4

[0125]

[0126] In Table 7, the object side surface and the image side surface of any lens of the first lens E1 and the second lens E2 are both Q-type aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0127]

[0128] Wherein, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, K is the cone coefficient, Am is the aspherical coefficient, rmax is the maximum radial radius coordinate, and u=r / rmax. Table 8 shows the cone coefficients and high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of each aspherical surface that can be used in Example 4.

[0129] Table 8: Aspheric surface related values ​​of lens surface in Example 4

[0130]

[0131] Figure 8 The MTF curve and MTF defocus curve of the optical imaging lens of Example 4 are shown. The MTF curve represents the MTF values ​​in the meridian and sagittal directions of different fields of view at different spatial frequencies. The MTF defocus curve represents the MTF separation in the meridian and sagittal directions of different fields of view at different spatial frequencies. The lower the MTF separation in the meridian and sagittal directions, the better the imaging quality of the optical imaging lens. It can be seen from the figure that the optical imaging lens given in Example 4 can achieve good imaging quality.

[0132] In Examples 1-4, the basic data are shown in Table 9 below:

[0133] Table 9 Basic data of Examples 1-4

[0134]

[0135] In Examples 1-4, the conditional formula is shown in Table 10 below:

[0136] Table 10 Conditional formula of Example 1-4

[0137]

[0138] A camera module at least includes an optical lens, in which a small single infrared wide-angle optical imaging system is installed. The optical imaging system adopts a combination of two plastic lenses, has the advantages of high pixel, wide angle and small aperture, compact structure, easy processing and installation, and at the same time, the configuration of large aperture can increase the amount of light entering the optical system and higher imaging quality, realizing a wide-angle range while taking into account the resolution ability of the lens, so that it can better capture the detailed information of the object, and at the same time can improve the ability of the optical lens to capture the details of the photographed object, so as to meet people's needs for wide-angle high-definition imaging in industrial production and manufacturing.

[0139] As described above, one or more implementation methods are provided in combination with specific contents, and the specific implementation of the utility model is not limited to these descriptions. Any method, structure, etc. similar to or identical to the method, structure, etc. of the utility model, or a number of technical deductions or replacements based on the concept of the utility model, shall be regarded as the protection scope of the utility model.

Claims

1. A small single infrared large-angle optical imaging system, characterized in that: The optical axis includes a first lens and a second lens in sequence from the object plane to the image plane; The first lens has negative optical power, its object side surface is concave, and its image side surface is concave; The second lens has positive refractive power, its object side surface is concave, and its image side surface is convex; The optical imaging system satisfies the following relationship: 92<DFOV / (DT11*ImgD*TTL)<132; Wherein, DFOV is the maximum field of view of the optical imaging system, DT11 is the maximum effective semi-aperture of the object side of the first lens, TTL is the axial distance from the object side of the first lens to the imaging surface, and ImgD is half of the diagonal length of the effective pixel area on the imaging surface.

2. A small single infrared large angle optical imaging system according to claim 1, characterized in that: The optical imaging system satisfies the following relationship: 2.6<f*tan(DFVO) / T12<4.5; Wherein, f is the effective focal length of the optical imaging system, and T12 is the distance between the first lens and the second lens.

3. The small single infrared large angle optical imaging system according to claim 1, characterized in that: The optical imaging system satisfies the following relationship: 4.7<(f1-f2) / (f1+f2)<9.2; or 1.8<f2 / (f1-f2)<4.1; or 1.6<f1 / f12<2.5; Wherein, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, and f12 is the combined focal length of the first lens and the second lens.

4. A small single infrared large angle optical imaging system according to any one of claims 1 to 3, characterized in that: The optical imaging system satisfies the following relationship: 5.9<TTL / f<7.6; Wherein, TTL is the total length of the optical imaging system, and f is the effective focal length of the optical imaging system.

5. A small single infrared large angle optical imaging system according to any one of claims 1 to 3, characterized in that: The optical imaging system satisfies the following relationship: 2.6<TTL / (CT1+CT2)<3.5; Wherein, TTL is the total length of the optical imaging system, CT1 is the center thickness of the first lens, and CT2 is the center thickness of the second lens.

6. A small single infrared large-angle optical imaging system according to any one of claims 1 to 3, characterized in that: The optical imaging system satisfies the following relationship: 0.3<|(R2-R1) / (R4-R3)|<1.5; Among them, R1 is the curvature radius of the object side of the first lens, R2 is the curvature radius of the image side of the first lens, R3 is the curvature radius of the object side of the second lens, and R4 is the curvature radius of the image side of the second lens.

7. A small single infrared large angle optical imaging system according to any one of claims 1 to 3, characterized in that: The optical imaging system satisfies the following relationship: 0.7<DT12 / CT2<1.3; Wherein, DT12 is the maximum effective semi-aperture of the first lens on the image side, and CT2 is the center thickness of the second lens on the optical axis.

8. A small single infrared large angle optical imaging system according to any one of claims 1 to 3, characterized in that: The maximum effective semi-aperture of the first lens object side is ≤1.11mm; and / or The total lens length of the optical imaging system is ≤2.7mm, the full field of view angle is >157°, and the F number is ≤3.

3.

9. A small single infrared large-angle optical imaging system according to any one of claims 1 to 3, characterized in that: The first lens and the second lens are both aspherical plastic lenses.

10. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with a small single infrared large-angle optical imaging system as described in any one of claims 1 to 9.

Images