High-resolution confocal imaging optical system and its application in camera modules
By designing a reasonable combination of 7 lenses, the problem of miniaturization of high-pixel imaging lenses in the visible and infrared bands has been solved, achieving high stability and low-cost imaging in harsh environments, and meeting the needs of multiple fields of application.
Patent Information
- Application Number
- CN202522319568.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2026-11-06
- Estimated Expiration
- 2035-10-31
AI Technical Summary
Existing imaging lenses struggle to achieve high resolution, miniaturization, and low cost in both visible and infrared bands, while maintaining good performance in harsh environments.
Design a high-pixel confocal imaging optical system consisting of 7 lenses. By rationally matching the lens shape and optical power, optimizing the focal length, refractive index and Abbe number of the lens combination, the size and distortion of the optical system are controlled to ensure high imaging quality under extreme temperature environments.
It achieves high-resolution, confocal, miniaturized, and low-cost imaging lenses that maintain good stability in harsh environments, have a compact structure, and are easy to manufacture and install.
Smart Images
Figure CN224946252U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical imaging, and more particularly to a high-pixel confocal imaging optical system and a camera module for its application. Background Technology
[0002] In recent years, with the advancement of technology and the development of mobile internet, people's love for photography has been increasing, leading to the rapid development of optical imaging lenses. These lenses are now widely used in various fields such as smartphones, smart homes, tablets, video conferencing, vehicle monitoring, security monitoring, and intelligent transportation systems. However, current imaging lenses on the market struggle to meet the requirements of high pixel count, miniaturization, and low cost in both the visible and infrared wavelengths. Therefore, designing and manufacturing low-cost confocal lenses that produce clear images in confocal focus and maintain good and stable performance even in harsh environments is of great significance. Utility Model Content This application aims to provide a high-pixel, miniaturized, low-cost, high-strength confocal imaging optical system that can be used in extreme temperature environments, and can meet the needs of multiple fields.
[0003] A high-pixel confocal imaging optical system comprises, along the optical axis from the object plane to the image plane, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens has negative optical power, and its object side is convex while its image side is concave. The second lens has optical power, with its object side being concave and its image side being convex; The third lens has positive optical power and its image-side surface is convex. The fourth lens has positive optical power, and its object side is convex, as is its image side; The fifth lens has negative optical power, and its object side is concave, as is its image side; The sixth lens has positive optical power, and its object side is convex, and its image side is convex. The seventh lens has optical power and its object side is convex.
[0004] Preferably, the optical system satisfies the following conditions: |f12 / f34|<3.0; |f12 / f56|<3.0; Where f12 is the combined focal length of the first and second lenses, f34 is the combined focal length of the third and fourth lenses, and f56 is the combined focal length of the fifth and sixth lenses.
[0005] Preferably, the optical system satisfies the following conditions: -2 <f / f123<0; 0 <f / f567<2; Where f is the effective focal length of the optical imaging system, f123 is the combined focal length of the first, second and third lenses, and f567 is the combined focal length of the fifth, sixth and seventh lenses.
[0006] Preferably, the optical system satisfies the following conditions: TTL / f < 10; Where f is the effective focal length of the optical imaging system, and TTL is the on-axis distance from the object side of the first lens to the imaging plane.
[0007] Preferably, the optical system satisfies the following conditions: f / BFL < 2.5; Where f is the effective focal length of the optical imaging system, and BFL is the optical back focal length of the optical imaging lens.
[0008] Preferably, each lens of the optical system satisfies the following condition: 15.0 <DFOV / IHD<25.0; Wherein, DFOV is the maximum field of view of the target surface diagonally opposite the imaging system of the optical system, and IHD is the target surface diagonally opposite the imaging system of the optical system.
[0009] Preferably, the optical system satisfies the following conditions: 15<(vd1+vd4) / (nd1+nd4)<50; 8<| (vd3-vd2) / (nd2-nd3) |<14; Wherein, nd1 is the refractive index of the first lens, vd1 is the Abbe number of the first lens, nd4 is the refractive index of the fourth lens, vd4 is the Abbe number of the fourth lens, nd2 is the refractive index of the second lens, vd2 is the Abbe number of the second lens, nd3 is the refractive index of the second lens, and vd3 is the Abbe number of the third lens.
[0010] Preferably, the optical system satisfies the following conditions: | DIS / (IHD / 2)| < 19.5; Wherein, DIS represents the optical distortion corresponding to the diagonal field of view of the optical imaging system, and IHD represents the diagonal target surface of the optical imaging system.
[0011] Preferably, the optical system satisfies the following conditions: The fifth and sixth lenses are cemented lenses, 10 <vd5 / nd5<40;10<vd6 / nd6<40; Wherein, nd5 is the refractive index of the fifth lens, vd5 is the Abbe number of the fifth lens, nd6 is the refractive index of the sixth lens, and vd6 is the Abbe number of the sixth lens.
[0012] Preferably, the optical system satisfies the following conditions: 2.2 <TTL / IHD<8.8; Where TTL is the axial distance from the object side of the first lens to the imaging surface, and IHD is half the diagonal length of the effective pixel area on the imaging surface.
[0013] On the other hand, this application also provides a camera module in which the above-mentioned high-pixel confocal imaging optical system is installed in the camera lens.
[0014] Compared with the prior art, the beneficial effects of this application are as follows: This utility model provides a high-pixel confocal imaging optical system and its application camera module, which is mainly composed of 7 lenses. Through the reasonable combination of lens shape and optical power, it effectively meets the design requirements of confocal, high resolution and miniaturization of optical imaging systems. It has the advantages of high pixel count, confocal, miniaturization and low cost. It can maintain good and stable performance in harsh environments. It has a compact structure and is easy to process and install. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.
[0016] Figure 1 This is a schematic diagram of the structure of the optical system or camera module in Embodiment 1 of this application; Figure 2 This is the MTF curve of the optical system or camera module in the visible light band of Embodiment 1 of this application; Figure 3 This is the MTF curve of the near-infrared band of the optical system or camera module of Embodiment 1 of this application; Figure 4 This is a schematic diagram of the structure of the optical system or camera module in Embodiment 2 of this application; Figure 5 This is the MTF curve of the optical system or camera module in the visible light band of Embodiment 2 of this application; Figure 6 This is the MTF curve of the near-infrared band of the optical system or camera module of Embodiment 2 of this application; Figure 7 This is a schematic diagram of the structure of the optical system or camera module in Embodiment 3 of this application; Figure 8 This is the MTF curve of the optical system or camera module in the visible light band of Embodiment 3 of this application; Figure 9 This is the MTF curve of the near-infrared band of the optical system or camera module of Embodiment 3 of this application. Detailed Implementation
[0017] like Figure 1-9 As shown, this application provides a high-pixel confocal imaging lens and a camera module for its application, including a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and a seventh lens E7 arranged sequentially from the object side. The first lens E1 has negative optical power, and its object side is convex and its image side is concave. The second lens E2 has optical power, with its object side being concave and its image side being convex; The third lens E3 has positive optical power and its image-side surface is convex. The fourth lens E4 has positive optical power, and its object side is convex, and its image side is convex. The fifth lens E5 has negative optical power, and its object side is concave, and its image side is concave. The sixth lens E6 has positive optical power, and its object side is convex, and its image side is convex. The seventh lens E7 has optical power and its object side is convex.
[0018] This utility model provides an optical system and its application camera module, which is mainly composed of 7 lenses. Through the reasonable combination of lens shape and optical power, it effectively meets the design requirements of confocal, high resolution and miniaturization of optical imaging system.
[0019] Furthermore, as a preferred embodiment of this utility model and not a limitation thereof, the optical system satisfies the following condition: TTL / f < 10, where f is the effective focal length of the optical imaging system, and TTL is the on-axis distance from the object side of the first lens to the imaging plane. By reasonably balancing the relationship between the effective focal length and the TTL of the optical imaging system, the size of the optical imaging system can be effectively reduced, achieving the requirement of miniaturization.
[0020] Furthermore, as a preferred embodiment of this utility model and not a limitation thereof, the optical system satisfies the condition that f / BFL < 2.5, where f is the effective focal length of the optical imaging system and BFL is the optical back focal length of the optical imaging lens. By effectively controlling the range of the effective focal length and optical back focal length of the optical imaging system, high imaging quality is ensured under varying temperature conditions.
[0021] Further, as a preferred but non-limiting embodiment of the present utility model, the optical system satisfies the following condition: 5.0<DFOV / IHD<25.0; where DFOV is the maximum diagonal target surface field of view angle of the imaging system of the optical system, and IHD is the diagonal target surface of the imaging system of the optical system. By controlling the relationship between the field of view angle and the maximum target surface, the viewing angle range of the imaging system is effectively corrected, and the maximum field of view angle range is increased.
[0022] Further, as a preferred but non-limiting embodiment of the present utility model, the optical system satisfies the following conditions: 15<(vd1+vd4) / (nd1+nd4)<50; 8<|(vd3-vd2) / (nd2-nd3)|<14, where nd1 is the refractive index of the first lens, vd1 is the Abbe number of the first lens, nd4 is the refractive index of the fourth lens, vd4 is the Abbe number of the fourth lens, nd2 is the refractive index of the second lens, vd2 is the Abbe number of the second lens, nd3 is the refractive index of the third lens, and vd3 is the Abbe number of the third lens. By defining the refractive indices and Abbe numbers of the first lens, the second lens, the third lens and the fourth lens, the optical imaging system obtains a reasonable light deflection angle and a reasonable distribution of optical power, effectively reduces the component tolerance sensitivity, and improves the quality of the optical imaging system. At the same time, by balancing the relationship between the focal lengths, the performance difference between the visible light and infrared bands is corrected, ensuring a small focal shift and high imaging quality between daytime and night vision.
[0023] Further, as a preferred but non-limiting embodiment of the present utility model, the optical system satisfies the following condition: |DIS / (IHD / 2)|<19.5, where DIS is the optical distortion corresponding to the diagonal field of view angle of the optical imaging system, and IHD is the diagonal target surface of the imaging system of the optical system. By controlling the distortion of the optical imaging system and the maximum target surface, the imaging requirements for daytime and nighttime are met, and high imaging quality is achieved under a large field of view angle.
[0024] Further, as a preferred but non-limiting embodiment of the present utility model, the optical system satisfies the following conditions: -2<f / f123<0, 0<f / f567<2, where f is the effective focal length of the optical imaging system, f123 is the combined focal length of the first lens, the second lens and the third lens, and f567 is the combined focal length of the fifth lens, the sixth lens and the seventh lens. By controlling the relationship between the effective focal length of the optical imaging system, the combined focal length of the first, second and third lenses and the combined focal length of the fifth, sixth and seventh lenses, the light trend is reasonably controlled, the high sensitivity problem of the optical imaging system is avoided, the astigmatism generated by the lens is corrected, so as to improve the imaging quality of the optical system.
[0025] Further, as a preferred but non-limiting embodiment of the present utility model, the optical system satisfies the following conditions: the fifth lens and the sixth lens are cemented lenses, 10<vd5 / nd5<40; 10<vd6 / nd6<40, where nd5 is the refractive index of the fifth lens, vd5 is the Abbe number of the fifth lens, nd6 is the refractive index of the sixth lens, and vd6 is the Abbe number of the sixth lens. By controlling the material of the cemented lens, the chromatic aberration of the optical imaging system is effectively reduced, and the risks of purple fringing and color shift are lowered. Meanwhile, high performance under night vision is ensured.
[0026] Further, as a preferred but non-limiting embodiment of the present utility model, the optical system satisfies the following conditions: |f12 / f34|<3.0; |f12 / f56|<3.0, where f12 is the combined focal length of the first lens and the second lens, f34 is the combined focal length of the third lens and the fourth lens, and f56 is the combined focal length of the fifth lens and the sixth lens. By controlling the combined focal length between the lenses within a reasonable range, the spherical aberration generated by the entire system can be balanced, so as to control the spherical aberration of the system, which is beneficial to improving the imaging quality of the system, and at the same time effectively ensures that the optical imaging system has good performance at high and low temperatures.
[0027] Further, as a preferred but non-limiting embodiment of the present utility model, each lens of the optical system satisfies the following condition: 2.2<TTL / IHD<8.8; TTL is the on-axis distance from the object side of the first lens to the imaging plane, and IHD is half of the diagonal length of the effective pixel area on the imaging plane. By controlling the relationship between the total length of the optical system and the imaging area, it is beneficial to the increase of the field of view, and at the same time realizes the miniaturization of the high-pixel confocal lens.
[0028] Specifically, as a preferred but non-limiting embodiment of the present utility model, reference is made below to Figures 1 to 3 the optical imaging lens according to Embodiment 1 of the present application will be described. Figure 1 A schematic structural diagram of the optical imaging lens according to Embodiment 1 of the present application is shown.
[0029] As shown in Figure 1 the figure, the optical imaging lens according to the exemplary embodiment of the present application sequentially includes from the object side to the image side along the optical axis: a first lens E1, a second lens E2, a third lens E3, a stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an imaging plane S17.
[0030] The first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being concave and its image-side surface S4 being convex. The third lens E3 has positive optical power, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has positive optical power, with its object-side surface S8 being convex and its image-side surface S9 being convex. The fifth lens E5 has negative optical power, with its object-side surface S10 being concave and its image-side surface S11 being concave. The sixth lens E6 has positive optical power, with its object-side surface S12 being convex and its image-side surface S13 being convex. The seventh lens E7 has negative optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave. The filter E8 has an object-side surface S15 and an image-side surface S16. Light from the object passes sequentially through surfaces S1 to S16 and is finally imaged onto the imaging surface S17.
[0031] Table 1 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 1, wherein the units for radius of curvature and thickness are millimeters (mm).
[0032] Table 1
[0033] In Table 1, the object-side surface and image-side surface of any one of the following lenses—E2, E3, E5, E6, and E7—are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:
[0034] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 2 gives the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 for each aspherical surface that can be used in the first embodiment.
[0035] Table 2
[0036] Specifically, as a preferred embodiment of the present invention and not a limitation thereof, the following references are made. Figures 4 to 6 Describes an optical imaging lens according to Embodiment 2 of this application. Figure 4 A schematic diagram of the structure of an optical imaging lens according to Embodiment 2 of this application is shown.
[0037] like Figure 4As shown, the optical imaging lens according to an exemplary embodiment of this application includes, in sequence along the optical axis from the object side to the image side: a first lens E1, a second lens E2, a third lens E3, an aperture stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an imaging surface S17.
[0038] The first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being convex. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has positive optical power, with its object-side surface S8 being convex and its image-side surface S9 being convex. The fifth lens E5 has negative optical power, with its object-side surface S10 being concave and its image-side surface S11 being concave. The sixth lens E6 has positive optical power, with its object-side surface S12 being convex and its image-side surface S13 being convex. The seventh lens E7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being convex. The filter E8 has an object-side surface S15 and an image-side surface S16. Light from the object passes sequentially through surfaces S1 to S16 and is finally imaged onto the imaging surface S17.
[0039] Table 3 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 2, wherein the units for radius of curvature and thickness are millimeters (mm).
[0040] Table 3
[0041] In Table 3, the object-side surface and image-side surface of any one of the following lenses—E2, E3, E5, E6, and E7—are aspherical. The surface shape of this aspherical lens can be defined using, but is not limited to, the following aspherical formula:
[0042] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 4 gives the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, and A18 for each aspherical surface that can be used in the second embodiment.
[0043] Table 4
[0044] Specifically, as a preferred embodiment of the present invention and not a limitation thereof, the following references are made. Figures 7 to 9Describes an optical imaging lens according to Embodiment 3 of this application. Figure 7 A schematic diagram of the structure of an optical imaging lens according to Embodiment 3 of this application is shown.
[0045] like Figure 7 As shown, the optical imaging lens according to an exemplary embodiment of this application includes, in sequence along the optical axis from the object side to the image side: a first lens E1, a second lens E2, a third lens E3, an aperture stop STO, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8, and an imaging surface S17.
[0046] The first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being concave and its image-side surface S4 being convex. The third lens E3 has positive optical power, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has positive optical power, with its object-side surface S8 being convex and its image-side surface S9 being convex. The fifth lens E5 has negative optical power, with its object-side surface S10 being concave and its image-side surface S11 being concave. The sixth lens E6 has positive optical power, with its object-side surface S12 being convex and its image-side surface S13 being convex. The seventh lens E7 has negative optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave. The filter E8 has an object-side surface S15 and an image-side surface S16. Light from the object passes sequentially through surfaces S1 to S16 and is finally imaged onto the imaging surface S17.
[0047] Table 5 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 3, wherein the units for radius of curvature and thickness are millimeters (mm).
[0048] Table 5
[0049] In Table 5, the object-side surface and image-side surface of any one of the following lenses—E2, E3, E5, E6, and E7—are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:
[0050] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 6 gives the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 for each aspherical surface that can be used in the third embodiment.
[0051] Table 6
[0052] In Examples 1-3, each conditional expression satisfies the conditions in the table below: Table 7
[0053] A camera module includes at least an optical lens, in which the aforementioned optical system is installed. The camera lens of this embodiment is mainly composed of 7 lenses. Through the reasonable combination of lens shape and optical power, the design requirements of confocal, high resolution and miniaturization of the optical imaging system are effectively met.
[0054] The above description provides one or more embodiments in conjunction with specific content, and does not imply that the specific implementation of this utility model is limited to these descriptions. Any methods or structures that are similar to or identical to those of this utility model, or any technical deductions or substitutions made based on the concept of this utility model, should be considered within the protection scope of this utility model.
Claims
1. A high-pixel confocal imaging optical system, comprising, sequentially from the object plane to the image plane along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens, characterized in that: The first lens has negative optical power, and its object side is convex while its image side is concave. The second lens has optical power, with its object side being concave and its image side being convex; The third lens has positive optical power and its image-side surface is convex. The fourth lens has positive optical power, and its object side is convex, as is its image side; The fifth lens has negative optical power, and its object side is concave, as is its image side; The sixth lens has positive optical power, and its object side is convex, and its image side is convex. The seventh lens has optical power and its object side is convex. The optical system satisfies the following conditions: TTL / f < 10; f / BFL < 2.5; 15 < (vd1 + vd4) / (nd1 + nd4) < 50; and 8<|(vd3-vd2) / (nd2-nd3)|<14; Where f is the effective focal length of the optical system, TTL is the on-axis distance from the object side of the first lens to the imaging plane, BFL is the optical back focal length of the optical system, nd1 is the refractive index of the first lens, vd1 is the Abbe number of the first lens, nd4 is the refractive index of the fourth lens, vd4 is the Abbe number of the fourth lens, nd2 is the refractive index of the second lens, vd2 is the Abbe number of the second lens, nd3 is the refractive index of the third lens, and vd3 is the Abbe number of the third lens.
2. The high-pixel confocal imaging optical system according to claim 1, characterized in that, The optical system satisfies the following conditions: |f12 / f34| < 3.0; and / or |f12 / f56| < 3.0; Wherein, f12 is the combined focal length of the first lens and the second lens, f34 is the combined focal length of the third lens and the fourth lens, and f56 is the combined focal length of the fifth lens and the sixth lens.
3. The high-pixel confocal imaging optical system according to claim 1, characterized in that, The optical system satisfies the following conditions: -2 < f / f123 < 0; and / or 0 < f / f567 < 2; Where f is the effective focal length of the optical system, f123 is the combined focal length of the first lens, the second lens and the third lens, and f567 is the combined focal length of the fifth lens, the sixth lens and the seventh lens.
4. The high-pixel confocal imaging optical system according to any one of claims 1-3, characterized in that, The optical system satisfies the following conditions: |DIS / (IHD / 2)| < 19.5; Wherein, DIS is the optical distortion corresponding to the diagonal field of view of the optical system, and IHD is half the diagonal length of the effective pixel area on the imaging surface.
5. The high-pixel confocal imaging optical system according to any one of claims 1-3, characterized in that, The fifth lens and the sixth lens are cemented lenses and satisfy the following conditions: 10 < vd5 / nd5 < 40; 10 < vd6 / nd6 < 40; Wherein, nd5 is the refractive index of the fifth lens, vd5 is the Abbe number of the fifth lens, nd6 is the refractive index of the sixth lens, and vd6 is the Abbe number of the sixth lens.
6. The high-pixel confocal imaging optical system according to any one of claims 1-3, characterized in that, The optical system satisfies the following conditions: 2.2 < TTL / IHD < 8.8; and / or 15.0 < DFOV / IHD < 25.0; Wherein, DFOV is the maximum diagonal field of view of the optical system, TTL is the on-axis distance from the object side of the first lens to the imaging surface, and IHD is half the diagonal length of the effective pixel area on the imaging surface.
7. A camera module, characterized in that, It includes at least an optical lens, wherein the optical lens is equipped with the high-pixel confocal imaging optical system according to any one of claims 1-6.