A small single infrared large-angle optical imaging system and its applied camera module

Abstract

The present invention 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 also taking into account the lens's resolution capability, enabling the system to better capture detailed information of objects. This also improves the optical lens's ability to capture details of photographed objects. The system has the advantages of high pixels, a wide angle, and a small aperture, a compact structure, and is easy to process and install. Furthermore, the large aperture configuration can increase the amount of light entering the optical system and achieve higher imaging quality, thereby meeting the needs of people for 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, rapid advances in artificial intelligence (AI) technology have driven the industry's transition toward unmanned, intelligent operations. In daily industrial production and manufacturing, people are increasingly accustomed to relying on intelligent machines to improve efficiency and speed. Machine vision-based inspection and monitoring systems have become a key component in improving the speed and efficiency of industrial production and manufacturing, and image acquisition through a camera is undoubtedly a prerequisite for achieving machine vision.

[0003] However, because industrial lenses are primarily used in complex production environments, they place extremely high demands on the cameras they carry, requiring not only a wide field of view (FOV) but also excellent imaging performance. Currently, most industrial lenses on the market utilize multiple glass and plastic lenses to achieve wide angles and excellent imaging performance. This results in large lenses, high costs, and is not conducive to market adoption. Furthermore, with the increasing miniaturization of optoelectronic components and the increasing interference from strong light during production, the market urgently needs a single infrared optical imaging lens with a small size, wide FOV, and low cost. Summary of the Invention

[0004] To address the problems of existing industrial lenses, such as large size, high cost, and general imaging, the present invention provides a small single-infrared wide-angle optical imaging system and a camera module used therein. By using a combination of two plastic lenses, a wide-angle range is achieved while also taking into account the lens's resolution capability, enabling it to better capture object details. At the same time, it can also improve the optical lens's ability to capture details of photographed objects, thereby meeting people's needs for wide-angle, high-definition imaging in industrial production and manufacturing.

[0005] The technical solutions adopted in this application are:

[0006] A small single infrared large-angle optical imaging system, which is composed of a first lens, an aperture, a second lens, and an infrared filter in sequence from the object plane to the image plane along the 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 single infrared industrial optical imaging 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 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 and second lenses.

[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 image side of the first lens, and CT2 is the center thickness of the second lens on the optical axis.

[0032] Preferably, the maximum effective semi-aperture of the objective 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 of view 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 includes at least 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 present invention has the following advantages:

[0037] The present invention 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 also taking into account the lens's resolution capability, enabling the system to better capture detailed information of objects. This also improves the optical lens's ability to capture details of photographed objects. The system has the advantages of high pixels, a wide angle, and a small aperture, a compact structure, and is easy to process and install. Furthermore, the large aperture configuration can increase the amount of light entering the optical system and achieve higher imaging quality, thereby meeting the needs of people 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 following briefly introduces the drawings required for describing the embodiments.

[0039] Figure 1 1 is a schematic structural diagram of an optical imaging system or camera module according to Example 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 2 is a schematic structural diagram of an optical imaging system or camera module according to embodiment 2 of the present application;

[0042] Figure 4 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 3 is a schematic structural diagram of an optical imaging system or camera module according to Example 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 4 is a schematic structural 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 present invention discloses a small single-infrared wide-angle optical imaging system, which is mainly used in the industrial field. By using a combination of two plastic lenses, a wide-angle range is achieved while also taking into account the lens's resolution capability, enabling it to better capture object details. At the same time, it can also improve the optical lens's ability to capture details of photographed objects, thereby meeting people's needs for wide-angle, high-definition imaging in industrial production and manufacturing.

[0051] Furthermore, the single infrared industrial optical imaging satisfies the following relationship:

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

[0053] Here, DFOV is the maximum field of view of the optical imaging system, DT11 is the maximum effective semi-aperture of the first lens's object side, TTL is the on-axis distance from the first lens's object side to the imaging surface, and ImgD is half the diagonal length of the effective pixel area on the imaging surface. This relationship reflects the constraints imposed on the optical lens's field of view and thinness, enabling the optical system to meet wide-angle requirements while also maintaining excellent thinness and lightness, ensuring the optical system's ultra-wide-angle, miniaturized, and thin characteristics. When the relationship falls below the lower limit, while ensuring the optical lens's field of view remains ultra-wide, further increasing DT11*TTL*IamgD will overly compress the lens's thinness and lightness, hindering its performance. When the relationship exceeds the upper limit, the lens struggles to achieve good imaging resolution.

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

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

[0056] Where f is the effective focal length of the optical imaging system, and T12 is the spacing between the first and second lenses. This relationship reflects the constraints on the field of view angle of the optical lens and the spacing between the lenses. This allows the optical system to meet wide-angle requirements while also maintaining a small optical focal length, ensuring the lens's ultra-wide-angle and compact design. When the value is above or below the upper or lower limits of the relationship, while maintaining an ultra-wide-angle field of view, T12 will be further reduced. This will over-compact the thickness of the optical lens and the air space between the lenses, hindering lens processing and reducing the imaging resolution of the optical lens.

[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, the optical power is prevented from being excessively concentrated on the second lens. At the same time, it helps to constrain the image side of the first lens and the surface shape of the second lens, avoiding excessive bending that affects the processing and manufacturability 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 and manufacturability 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] Where f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. By properly distributing the focal power ratio of the first and second optical elements close to the image plane within a reasonable range, the residual spherical aberration can be balanced to balance the aberrations, thereby fine-tuning and controlling the aberrations of the system and enhancing the precise control of on-axis field aberrations.

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

[0064] 1.6<f1 / f12<2.5;

[0065] Here, 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 combined effective focal length of the first and second lenses, the optical power of the first and second lenses can be properly distributed, allowing the second lens to have more diverse compatibility. This balances the internal aberrations of the optical lens while meeting the requirements of a miniaturized design. This helps adjust the field curvature at the edge of the image, reduces distortion, and improves the resolution of the optical lens.

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

[0067] 5.9<TTL / f<7.6;

[0068] Where 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 and second lenses can be appropriately set. This effectively suppresses the significant expansion of the incident light beam due to divergence through the first lens without excessively strengthening the converging effect of the lens group on the image side of the second lens. This prevents large aberrations in the system and effectively limits the length of the optical lens, facilitating its miniaturization.

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

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

[0071] Where 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 in the imaging lens, the overall length of the optical lens can be effectively constrained to meet 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 curvature radii of the image and object sides of the first lens to the difference in the curvature radii of the image and object sides of the second lens, the total deflection angle of the object and image sides 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. It is also conducive to reasonably controlling the curvature of the second lens, giving it better processing and molding characteristics, while also preventing excessive deflection of light when transmitting between lenses, reducing the processing difficulty of the optical lens assembly.

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

[0076] 0.7<DT12 / CT2<1.3;

[0077] Where DT12 is the maximum effective semi-aperture of the image-side surface of the first lens, and CT2 is the center thickness of the second lens on the optical axis. When the above conditional equation is met, since the effective semi-aperture of a lens and its thickness are mutually influenced, properly controlling the effective semi-aperture of the image-side surface of the first lens can effectively shorten the center thickness of the second lens on the optical axis, further compressing the overall lens assembly volume, which helps reduce the total optical length of the optical system and reduces 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 surface 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, resulting in an excessively thin barrel wall, seriously affecting the strength and quality of the lens. If the outer diameter of the first lens barrel is greater than 4.5mm, the end area cannot be effectively reduced, which has an adverse effect on reducing the screen-to-body ratio.

[0078] Furthermore, the maximum effective semi-aperture of the first lens on the object side is ≤1.11mm, the total lens length of the optical imaging system is ≤2.7mm, the full field of view is >157°, and the F-number is ≤3.3. The single infrared wide-angle industrial optical imaging lens configured in the present invention has the advantages of high pixel count, wide angle, and small aperture, and is compact for easy processing and installation. Furthermore, the large aperture configuration increases the amount of light entering the optical system and improves imaging quality.

[0079] In the four cases described, the first and second lenses are both aspherical plastic lenses. The present invention discloses a single infrared wide-angle industrial optical lens. By combining two plastic lenses, it achieves a wide-angle range while also maintaining high resolution, enabling it to better capture detailed information about objects. This also improves the optical lens's ability to capture detailed information about the object being photographed, meeting the needs for wide-angle, high-definition imaging in industrial manufacturing.

[0080] Example 1

[0081] Specifically, as a preferred embodiment of the present invention but not limiting, the following reference is made to Figures 1 to 2 The optical imaging lens according to Example 1 of the present application is described. Figure 1 A schematic structural diagram of an optical imaging lens according to Example 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 refractive power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has positive refractive power, with its object-side surface S3 being concave and its image-side surface S4 being convex. The filter E3 has an object-side surface S5 and an image-side surface S6. The chip cover glass E4 has an object-side surface S7 and an image-side surface S8. Light from the object sequentially passes through surfaces S1 to S8 and is ultimately 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 curvature radius and thickness are both millimeters (mm).

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

[0086] Face number Surface type Curvature radius (mm) Thickness (mm) Material OBJ spherical surface endless 200 S1 Q-type aspheric surface -1.7822 0.3272 1.54,55.98 S2 Q-type aspheric surface 0.6597 0.6083 STO spherical surface endless 0.0839 S3 Q-type aspheric surface -5.4220 0.6194 1.63,23.35 S4 Q-type aspheric surface -0.3581 0.2281 S5 spherical surface endless 0.2100 1.52,64.21 S6 spherical surface endless 0.1931 S7 spherical surface endless 0.4000 1.52,64.21 S8 spherical surface endless 0.0325 S9 spherical surface endless 0

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

[0088]

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

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

[0091] Surface number S1 S2 S3 S4 K 1.21E+00 -4.34E+00 9.00E+01 -4.16E-01 A4 3.18E-01 -7.49E+03 -1.90E+08 7.46E-01 A6 -9.17E-03 -5.53E+03 2.41E+08 -1.48E-01 A8 1.03E-04 -2.93E+03 1.35E+08 3.34E-02 A10 8.14E-04 -1.12E+03 -1.88E+08 -2.12E-03 A12 4.04E-05 -2.99E+02 -2.97E+08 -7.11E-03 A14 -9.06E-06 -5.18E+01 -1.91E+08 7.30E-03 A16 6.97E-06 -5.18E+00 -6.92E+07 -3.89E-03 A18 -1.94E-06 -2.53E-01 -1.38E+07 3.23E-04 A20 -1.87E-06 -1.85E-02 -1.19E+06 1.78E-03 A22 2.64E-07 -5.41E-03 -3.47E-03 -2.03E-03 A24 1.56E-07 6.83E-03 2.43E-03 8.61E-04 A26 3.38E-07 -3.69E-03 -1.22E-03 7.03E-04 A28 -1.23E-07 -8.66E-03 -6.62E-04 -1.23E-03 A30 2.01E-09 -2.31E-03 3.29E-03 -7.06E-04

[0092] Figure 2 The MTF curve and MTF through focus curve of the optical imaging lens of Example 1 are shown. The MTF curve represents the MTF values ​​in the meridional and sagittal directions at different spatial frequencies and fields of view. The MTF through focus curve shows the separation of the MTF values ​​in the meridional and sagittal directions at different spatial frequencies and fields of view. The lower the separation of the MTF values ​​in the meridional and sagittal directions, the better the imaging quality of the optical imaging lens. The figure shows that the optical imaging lens of Example 1 can achieve excellent imaging quality.

[0093] Example 2

[0094] Specifically, as a preferred embodiment of the present invention but not limiting, the following reference is made to Figures 3 and 4 The optical imaging lens according to Example 2 of the present application is described. Figure 3 A schematic structural diagram of an optical imaging lens according to Example 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 refractive power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has positive refractive power, with its object-side surface S3 being concave and its image-side surface S4 being convex. The filter E3 has an object-side surface S5 and an image-side surface S6. The chip cover glass E4 has an object-side surface S7 and an image-side surface S8. Light from the object sequentially passes through surfaces S1 to S8 and is ultimately 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 system of Example 2, where the units of curvature radius and thickness are both millimeters (mm).

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

[0099] Face number Surface type Curvature radius (mm) Thickness (mm) Material OBJ spherical surface endless 200 S1 Q-type aspheric surface -1.8734 0.2452 1.60,61.46 S2 Q-type aspheric surface 0.7757 0.6097 STO spherical surface endless 0.0867 S3 Q-type aspheric surface -2.7775 0.4796 1.58,62.65 S4 Q-type aspheric surface -0.3161 0.2852 S5 spherical surface endless 0.2100 1.52,64.21 S6 spherical surface endless 0.1611 S7 spherical surface endless 0.4000 1.52,64.21 S8 spherical surface endless 0.0325 S9 spherical surface endless 0

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

[0101]

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

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

[0104] Surface number S1 S2 S3 S4 K 1.35E+00 -3.85E+00 4.16E+01 -1.14E+00 A4 3.45E-01 -7.49E+03 -1.90E+08 -1.80E-02 A6 -1.39E-02 -5.53E+03 2.42E+08 -2.52E-03 A8 -1.64E-03 -2.93E+03 1.35E+08 2.62E-04 A10 2.18E-03 -1.12E+03 -1.88E+08 -2.53E-04 A12 -6.66E-04 -2.99E+02 -2.97E+08 1.08E-04 A14 -7.95E-05 -5.18E+01 -1.92E+08 -7.41E-05 A16 1.77E-04 -5.18E+00 -6.92E+07 4.86E-05 A18 -9.66E-05 -2.65E-01 -1.38E+07 -1.91E-05 A20 -2.08E-05 -1.78E-02 -1.19E+06 2.33E-05 A22 4.74E-05 3.83E-03 -1.32E-03 -2.28E-05 A24 -1.22E-04 9.18E-04 1.02E-03 4.57E-06 A26 8.54E-05 -4.50E-03 -5.77E-04 -5.33E-06 A28 -6.03E-05 2.84E-03 -1.74E-04 7.38E-06 A30 3.42E-06 3.85E-03 1.27E-03 -2.15E-06

[0105] Figure 4 The MTF curve and MTF through focus curve of the optical imaging lens of Example 2 are shown. The MTF curve represents the MTF values ​​in the meridional and sagittal directions at different spatial frequencies and for different fields of view. The MTF through focus curve shows the separation of the MTF values ​​in the meridional and sagittal directions at different spatial frequencies. The lower the separation of the MTF values ​​in the meridional and sagittal directions, the better the imaging quality of the optical imaging lens. The figure shows that the optical imaging lens of Example 2 can achieve excellent imaging quality.

[0106] Example 3:

[0107] Specifically, as a preferred embodiment of the present invention but not limiting, the following reference is made to Figures 5 and 6 The optical imaging lens according to Example 3 of the present application is described. Figure 5 A schematic structural diagram of an optical imaging lens according to Example 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 refractive power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has positive refractive power, with its object-side surface S3 being concave and its image-side surface S4 being convex. The filter E3 has an object-side surface S5 and an image-side surface S6. The chip cover glass E4 has an object-side surface S7 and an image-side surface S8. Light from the object sequentially passes through surfaces S1 to S8 and is ultimately 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 system of Example 3, where the units of curvature radius and thickness are both millimeters (mm).

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

[0112] Face number Surface type Curvature radius (mm) Thickness (mm) Material OBJ spherical surface endless 200 S1 Q-type aspheric surface -1.7983 0.3027 1.56,64.16 S2 Q-type aspheric surface 0.5915 0.6242 STO spherical surface endless 0.0884 S3 Q-type aspheric surface -1.9875 0.4789 1.63,35.45 S4 Q-type aspheric surface -0.3376 0.3274 S5 spherical surface endless 0.2100 1.52,64.21 S6 spherical surface endless 0.2033 S7 spherical surface endless 0.4000 1.52,64.21 S8 spherical surface endless 0.0325 S9 spherical surface endless 0

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

[0114]

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

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

[0117]

[0118]

[0119] Figure 6 The MTF curve and MTF through focus curve of the optical imaging lens of Example 3 are shown. The MTF curve represents the MTF values ​​in the meridional and sagittal directions at different spatial frequencies and fields of view. The MTF through focus curve shows the separation of the MTF values ​​in the meridional and sagittal directions at different spatial frequencies and fields of view. The lower the separation of the MTF values ​​in the meridional and sagittal directions, the better the imaging quality of the optical imaging lens. The figure shows that the optical imaging lens of Example 3 can achieve excellent imaging quality.

[0120] Example 4:

[0121] 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 Example 4 of the present application is described. Figure 7 A schematic structural diagram of an optical imaging lens according to Example 4 of the present application is shown.

[0122] 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.

[0123] The first lens E1 has negative refractive power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has positive refractive power, with its object-side surface S3 being concave and its image-side surface S4 being convex. The filter E3 has an object-side surface S5 and an image-side surface S6. The chip cover glass E4 has an object-side surface S7 and an image-side surface S8. Light from the object sequentially passes through surfaces S1 to S8 and is ultimately imaged on the imaging surface S9.

[0124] Table 7 shows the surface type, curvature radius, thickness, and material of each lens of the optical imaging lens system of Example 4, where the units of curvature radius and thickness are both millimeters (mm).

[0125] Table 7: Basic parameters of the optical imaging system of Example 4

[0126]

[0127]

[0128] In Table 7, both the object side and the image side of the first lens E1 and the second lens E2 are Q-type aspheric surfaces. The surface shape of each aspheric lens can be defined by, but not limited to, the following aspheric formula:

[0129]

[0130] Where Z is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspheric surface, c is the curvature of the vertex of the aspheric surface, K is the conic coefficient, Am is the aspheric coefficient, rmax is the maximum radial radius coordinate, and u = r / rmax. Table 8 shows the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 of various aspheric surfaces that can be used in Example 4.

[0131] Table 8: Aspheric surface related values ​​of the lens surface of Example 4

[0132] Surface number S1 S2 S3 S4 K -9.25E+00 -1.12E+00 -9.00E+01 1.70E-02 A4 4.27E-01 -9.57E+03 6.85E+07 -4.76E-03 A6 -1.03E-01 -7.19E+03 -8.67E+07 -3.93E-04 A8 2.54E-02 -3.92E+03 -4.92E+07 2.01E-05 A10 -1.35E-02 -1.57E+03 6.73E+07 2.08E-07 A12 3.73E-03 -4.53E+02 1.08E+08 -3.91E-05 A14 -2.78E-03 -9.07E+01 7.01E+07 -1.30E-05 A16 2.34E-04 -1.20E+01 2.55E+07 -3.38E-06 A18 -6.85E-04 -1.01E+00 5.14E+06 -2.86E-06 A20 5.50E-04 -6.21E-02 4.49E+05 -2.43E-06 A22 -1.75E-04 3.91E-03 -2.39E-03 -2.39E-06 A24 -1.71E-04 6.58E-03 1.79E-03 4.76E-07 A26 -1.70E-04 -6.44E-03 -7.62E-04 -8.45E-07 A28 2.21E-05 2.13E-03 -1.94E-04 -1.11E-06 A30 -1.13E-04 4.29E-03 2.78E-03 -2.14E-07

[0133] Figure 8 The MTF curve and MTF through focus curve of the optical imaging lens of Example 4 are shown. The MTF curve represents the MTF values ​​in the meridional and sagittal directions at different spatial frequencies and for different fields of view. The MTF through focus curve shows the separation of the MTF values ​​in the meridional and sagittal directions at different spatial frequencies. The lower the separation of the MTF values ​​in the meridional and sagittal directions, the better the imaging quality of the optical imaging lens. The figure shows that the optical imaging lens of Example 4 can achieve excellent imaging quality.

[0134] In Examples 1-4, the basic data are shown in Table 9 below:

[0135] Table 9 Basic data of Examples 1-4

[0136] Basic data / Example 1 2 3 4 f1(mm) -0.87 -0.90 -0.78 -0.63 f2(mm) 0.59 0.58 0.60 0.50 f(mm) 0.36 0.38 0.37 0.37 TTL(mm) 2.70 2.51 2.67 2.22 DFOV(°) 158.00 158.00 158.00 158.00 f / EPD 3.14 3.19 3.3 2.7

[0137] In Examples 1-4, the conditional formula is shown in Table 10 below:

[0138] Table 10 Conditional formula for Examples 1-4

[0139] Conditional formula / Example 1 2 3 4 DT11 1.11 0.91 1.08 0.95 DT12 0.48 0.48 0.57 0.40 T12 0.69 0.70 0.71 0.37 IamgD 0.57 0.57 0.55 0.56 f12 0.36 0.38 0.37 0.37 R1 -1.78 0.66 -5.42 -0.36 R2 -1.87 0.78 -2.78 -0.32 R3 -1.80 0.59 -1.99 -0.34 R4 -0.99 1.01 -6.60 -0.38 CT1 0.33 0.25 0.30 0.42 CT2 0.62 0.48 0.48 0.41 f*tan(DFOV) 1.85 1.96 1.88 1.83 DFOV / (DT11*IamgD*TTL) 92.66 121.36 100.08 131.90 f*tan(DFVO) / T12 2.68 4.08 3.93 4.46 (f1-f2) / (f1+f2) 5.24 4.71 7.61 9.10 f2 / (f1-f2) 2.12 1.85 3.31 4.05 f1 / f12 2.40 2.36 2.12 1.69 TTL / f 7.50 6.60 7.29 5.97 TTL / (CT1+CT2) 2.85 3.46 3.41 2.67 |(R2-R1) / (R4-R3)| 0.48 1.08 1.45 0.32 DT12 / CT2 0.78 0.99 1.19 0.98

[0140] A camera module includes at least 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 and has the advantages of high pixels, wide angle and small aperture. It has a compact structure and is easy to process and install. At the same time, the large aperture configuration can increase the amount of light entering the optical system and higher imaging quality, achieving a wide-angle range while also taking into account the resolution capability of the lens, so that it can better capture the detailed information of the object. At the same time, it can also improve the optical lens's ability to capture the details of the photographed object, thereby meeting people's needs for wide-angle high-definition imaging in industrial production and manufacturing.

[0141] The above descriptions are provided in conjunction with specific content to provide one or more embodiments, and the specific implementation of the present invention is not limited to these descriptions. Any similarity or similarity with the methods, structures, etc. of the present invention, or any technical deduction or substitution based on the concept of the present invention, shall be considered within the scope of protection of the present invention.

Claims

1. A small single infrared large-angle optical imaging system, characterized by: Along the optical axis, from the object plane to the image plane, it is composed of the first lens, aperture, second lens, and infrared filter in sequence; 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 single infrared industrial optical imaging satisfies the following relationship: 92° / mm 3 <DFOV / (DT11*ImgD*TTL)<132° / mm 3 ; 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 on-axis 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; The optical imaging system satisfies the following relationship: 2.6<f*tan(DFVO) / T12<4.5; 4.7<(f1-f2) / (f1+f2)<9.2; 1.8<f2 / (f1-f2)<4.1; 1.6<f1 / f12<2.5; Wherein, f is the effective focal length of the optical imaging system, T12 is the distance between the first lens and the second lens, 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.

2. The small single infrared large-angle optical imaging system according to claim 1, 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.

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: 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.

4. The small single infrared large-angle optical imaging system according to claim 1, 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.

5. The small single infrared large-angle optical imaging system according to claim 1, 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 image side of the first lens, and CT2 is the center thickness of the second lens on the optical axis.

6. The small single infrared large-angle optical imaging system according to claim 1, characterized in that: The maximum effective semi-aperture of the objective side of the first lens is ≤1.11 mm.

7. The small single infrared large-angle optical imaging system according to claim 1, characterized in that: The first lens and the second lens are both aspherical plastic lenses; 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.

8. 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 according to any one of claims 1 to 7.

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