Glass-plastic day and night confocal lens and electronic equipment
By using a compact optical structure with six lenses and a reasonable combination of materials, the problem of lightweighting and miniaturization of day and night confocal lenses has been solved, achieving high-performance imaging and cost optimization.
Patent Information
- Application Number
- CN202520785844.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-04-24
AI Technical Summary
Existing day-night confocal lenses struggle to achieve both high performance and lightweight design, and are also costly.
It employs a compact optical structure with six lenses, and through the rational allocation of the refractive power and surface design of each lens, it uses a combination of glass spherical and plastic aspherical lenses, combined with high and low dispersion materials, and sets an aperture to optimize the light path and image quality.
Significantly shortens the overall lens length, reduces material and manufacturing costs, improves imaging resolution and stability, meets miniaturization requirements, and maintains excellent imaging quality and day/night confocal performance.
Smart Images
Figure CN224682465U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of day and night confocal lens technology, and in particular to a glass-plastic day and night confocal lens and electronic device. Background Technology
[0002] With the widespread application of security systems in various fields, day / night confocal lenses, as a key optical component, have attracted much attention due to their ability to achieve high-quality monitoring and imaging under all-weather conditions. This technology effectively solves the problem of image defocusing caused by the wavelength difference between visible light and infrared light when switching between day and night modes in traditional lenses.
[0003] However, existing day / night convergent lens designs often struggle to balance image quality and day / night convergent performance while maintaining lightweight and compact dimensions. On one hand, to meet the requirements of day / night convergence, lenses typically require complex optical structures, increasing their size and weight. For example, some lenses use numerous lenses to correct chromatic aberration and other aberrations, resulting in a larger overall size. On the other hand, to ensure image stability in various environments, lenses often require high-quality optical materials, which not only increases cost but also further limits lightweight design options.
[0004] In conclusion, although day and night confocal lenses have important application value in the field of security monitoring, how to achieve lightweight and small size while maintaining high performance remains a major challenge in the field of optical design. Utility Model Content
[0005] In view of this, the purpose of this utility model is to provide a glass-plastic day-night confocal lens and electronic device. This lens can at least solve one of the technical shortcomings mentioned in the background art.
[0006] According to one aspect of the present invention, a glass-plastic confocal lens for day and night is provided, wherein the lens comprises, in order from the object side to the image side: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens;
[0007] The first lens has negative refractive power, the object side of the lens is convex, and the image side of the lens is concave.
[0008] The second lens has negative refractive power, and the object side of the lens is concave, as is the image side of the lens.
[0009] The third lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface of the lens.
[0010] The fourth lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface of the lens.
[0011] The fifth lens has negative refractive power. The object-side surface of the lens is concave, and the image-side surface of the lens is also concave.
[0012] The sixth lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface.
[0013] In the aforementioned technical solution, the glass-plastic day / night confocal lens adopts a compact optical structure with six lenses. By rationally allocating the diopter and curvature design of each lens, material and manufacturing costs are effectively reduced, while the overall lens length is significantly shortened (TTL < 22.3mm), and the effective lens diameter is smaller than... The overall size is significantly reduced, meeting the requirements of miniaturized optical systems. In terms of imaging performance, the lens maintains an MTF value greater than 0.55 across the entire field of view at a high spatial frequency of 100 lp / mm, ensuring excellent imaging resolution and contrast. With a target surface height greater than 6.6 mm, it can be matched with a 1 / 2.7-inch image sensor, meeting high-resolution imaging requirements while also ensuring confocal optical performance day and night. By using two negative diopter lenses (the second and first lenses) consecutively, the field of view is compressed and the light beam is expanded, optimizing the light path and deflecting it towards the optical axis. This effectively reduces the outer diameter of subsequent lenses, significantly reducing the size and complexity of the optical system while maintaining a large field of view. Furthermore, the sixth lens employs a positive diopter design and sets its image-side surface to be convex, optimizing the deflection path of incident beams in each field of view, enabling efficient convergence on the imaging plane. This significantly suppresses spherical aberration, chromatic aberration, field curvature, and astigmatism in the optical system, improving overall image quality and system stability.
[0014] In some embodiments, the lens satisfies the following condition:
[0015] nd3 > 2.0
[0016] In the formula, nd3 is the refractive index of the third lens.
[0017] In the above technical solution, the glass-plastic day and night confocal lens uses a high refractive index material (satisfying the condition nd3>2.0) to reduce the distance between the lenses, thereby effectively shortening the overall length of the optical system. At the same time, while maintaining excellent imaging performance, it further reduces the complexity and volume of the system and improves the compactness of the optical system.
[0018] In some embodiments, an aperture stop is provided between the third lens and the fourth lens.
[0019] In the aforementioned technical solution, this glass-plastic confocal day / night lens improves the imaging quality of the optical system by placing an aperture stop between the third and fourth lenses and utilizing the aperture stop's ability to limit and control light. Specifically, by adjusting the distances between the third lens and the aperture stop, and between the aperture stop and the fourth lens, the incident angle and light path distribution are optimized, effectively correcting astigmatism, especially providing excellent correction for off-axis aberrations such as coma, distortion, and transverse aberration. This design not only enhances the system's imaging sharpness and contrast but also improves the overall performance and stability of the optical system, ensuring high-quality imaging results under different fields of view and lighting conditions.
[0020] In some embodiments, the first lens and the third lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspherical lenses.
[0021] In the aforementioned technical solution, this glass-plastic day / night confocal lens achieves an optimized balance between optical performance and manufacturing cost through the rational configuration of lens materials and types. Specifically, the first and third lenses employ a glass spherical lens design, ensuring the stability and environmental resistance of the optical system; while the second, fourth, fifth, and sixth lenses utilize a plastic aspherical lens design, fully leveraging the advantages of aspherical lenses in aberration correction. By increasing the order of even-order aspherical surfaces, the second, fourth, fifth, and sixth lenses significantly improve the utilization efficiency of each lens, thereby effectively reducing the number of lenses used. While maintaining system imaging quality, this significantly reduces the lens size, lowers manufacturing costs, and enhances the compactness and integration of the optical system.
[0022] In some embodiments, the second lens, the fourth lens, and the sixth lens are made of high dispersion materials; the third lens and the fifth lens are made of low dispersion materials.
[0023] In the aforementioned technical solution, the second, fourth, and sixth lenses of the glass-plastic confocal day / night lens are made of high-dispersion materials, while the third and fifth lenses are made of low-dispersion materials. This design utilizes the interaction of lenses with different dispersion coefficients to effectively counteract focus shift caused by wavelength differences, thereby significantly reducing chromatic aberration. Simultaneously, the second, fourth, fifth, and sixth lenses employ an aspherical lens design, precisely correcting spherical aberration and field curvature, further optimizing the overall performance of the optical system.
[0024] In some embodiments, the lens satisfies the following condition:
[0025] 7.5 <TTL / f<8.5
[0026] In the formula, TTL is the total optical length of the lens, and f is the focal length of the lens.
[0027] In the aforementioned technical solution, this glass-plastic day / night confocal lens optimizes the size of the optical system while ensuring image quality by precisely controlling the ratio of total optical length to focal length (TTL / f). Specifically, when the TTL / f is less than 7.5, the optical system may suffer from decreased image quality due to its excessively small size; while when the TTL / f is greater than 8.5, the optical system may be too large, hindering miniaturization design. By controlling the TTL / f between 7.5 and 8.5, the lens achieves the optimal balance between miniaturization and image quality.
[0028] According to another aspect of the present invention, an electronic device is provided, comprising the aforementioned glass-plastic day / night confocal lens; and
[0029] An image sensor is configured to receive images formed by the glass-plastic day / night confocal lens.
[0030] In the above technical solution, the advantage of this electronic device relies on the glass-plastic day and night confocal lens, which will not be elaborated here. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a structural schematic diagram of Example 1 of a glass-plastic confocal day-night lens according to this utility model;
[0033] Figure 2 This is the MTF curve of Example 1 of a glass-plastic day-night confocal lens of this utility model;
[0034] Figure 3 This is an MTF curve at 850nm wavelength for Example 1 of a glass-plastic day-night confocal lens of this utility model;
[0035] Figure 4 This is a Through Focus curve at 850nm wavelength for Example 1 of a glass-plastic day-night confocal lens of this utility model;
[0036] Figure 5 This is a Lateral Color curve of Example 1 of a glass-plastic day-night confocal lens of this utility model;
[0037] Figure 6 This is a structural schematic diagram of Example 2 of a glass-plastic day-night confocal lens according to this utility model;
[0038] Figure 7 This is the MTF curve of Example 2 of a glass-plastic day-night confocal lens of this utility model;
[0039] Figure 8 This is an MTF curve at 850nm wavelength for Example 2 of a glass-plastic day-night confocal lens of this utility model;
[0040] Figure 9 This is a Through Focus curve at 850nm wavelength for Example 2 of a glass-plastic day-night confocal lens of this utility model;
[0041] Figure 10 This is a Lateral Color curve of Example 2 of a glass-plastic day-night confocal lens of this utility model;
[0042] Figure 11 This is a structural schematic diagram of Example 3 of a glass-plastic day-night confocal lens according to this utility model;
[0043] Figure 12 This is the MTF curve of Example 3 of a glass-plastic confocal day and night lens of this utility model;
[0044] Figure 13 This is an MTF curve at 850nm wavelength for Example 3 of a glass-plastic day-night confocal lens of this utility model;
[0045] Figure 14 This is a Through Focus curve at 850nm wavelength for Example 3 of a glass-plastic day-night confocal lens of this utility model;
[0046] Figure 15 This is a Lateral Color curve of Example 3 of a glass-plastic day-night confocal lens of this utility model;
[0047] Figure 16 This is a schematic diagram of the structure of an electronic device example 4 of this utility model. Detailed Implementation
[0048] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are only for illustrating the present invention and do not limit the scope of the present invention. Similarly, the following embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.
[0049] The purpose of this invention is to provide a glass-plastic confocal lens with high optical performance for both day and night operation, and an electronic device thereof. Embodiments according to this invention will now be described in detail with reference to the accompanying drawings.
[0050] Figure 1 , Figure 6 , Figure 11 These are cross-sectional views of a glass-plastic confocal day / night lens (optical system) according to Examples 1 to 3. The glass-plastic confocal day / night lens according to Example 1 is used in imaging devices and interchangeable-lens optical devices, including digital video cameras, digital still cameras, broadcast cameras, and surveillance cameras. In each cross-sectional view, the left side is the object-side OBJ and the right side is the image-side IMA, with the optical axis OA. In each cross-sectional view, Li represents the i-th lens, and G1 represents the protective glass and filter. IMA represents the image plane, and when the glass-plastic confocal day / night lens according to Examples 1 to 3 is used in an imaging optical system for a digital video camera or digital still camera, a solid-state imaging element (photoelectric conversion element), such as a CMOS image sensor or a CCD image sensor, is arranged on the image plane IMA.
[0051] According to the various examples, the glass-plastic day and night confocal lenses include, in order from the object side to the image side, the lenses in the following order from the object side to the image side: first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, and sixth lens L6.
[0052] The first lens L1 has negative refractive power, with a convex object-side surface and a concave image-side surface; the second lens L2 has negative refractive power, with a concave object-side surface and a concave image-side surface; the third lens L3 has positive refractive power, with a convex object-side surface and a convex image-side surface; the fourth lens L4 has positive refractive power, with a convex object-side surface and a convex image-side surface; the fifth lens L5 has negative refractive power, with a concave object-side surface and a concave image-side surface; and the sixth lens L6 has positive refractive power, with a convex object-side surface and a convex image-side surface. An aperture stop ST is provided between the third lens L3 and the fourth lens L4.
[0053] The first lens L1 and the third lens L3 are glass spherical lenses, while the second lens L2, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are plastic aspherical lenses.
[0054] The second lens L2, the fourth lens L4, and the sixth lens L6 are made of high dispersion material; the third lens L3 and the fifth lens L5 are made of low dispersion material.
[0055] The glass-plastic day-night confocal lens in each example can satisfy at least one of the following setting conditions 1) to 3):
[0056] 1) 1.80 <nd1<1.85,40<vd1<45;
[0057] 2) 1.50 <nd2<1.60,55<vd2<60;
[0058] 3) 2.00 <nd3<2.05,29<vd3<35;
[0059] 4) 1.50 <nd4<1.55,50<vd4<60;
[0060] 5) 1.65 <nd5<1.70,19<vd5<25;
[0061] 6) 1.50 <nd6<1.55,50<vd6<60;
[0062] 7)7.5 <TTL / f<8.5;
[0063] In the above conditional expressions, nd1 to nd6 are the refractive indices of the first to sixth lenses, respectively, and vd1 to vd6 are the Abbe coefficients of the first to sixth lenses, respectively. TTL is the total optical length of the lens, and f is the focal length of the lens.
[0064] Please refer to the optical structure of Example 1. Figure 1 The specific parameters for Example 1 are shown in Tables 1 and 2 below. In Example 1, the lens focal length f' = 2.8 mm, and the total optical length (TTL) of the lens is less than 22.3 mm.
[0065] Table 1 Example 1 Parameter Table
[0066]
[0067] Table 2 Example 1 Aspheric Coefficients Table
[0068]
[0069]
[0070] Please see Figure 2 The MTF curve of the optical system in Example 1 shows that the MTF is greater than 0.5 across the entire field of view at 100 lp / mm. Please refer to [link / reference]. Figure 3 In Example 1, the MTF at 850nm wavelength shows a full-field MTF greater than 0.5 at 100 lp / mm. Please refer to [link / reference]. Figure 4 Example 1 shows the through-focus curve at 850nm wavelength, with an IRshift of less than 3µm. Please refer to [link / reference]. Figure 5 Example 1 shows the LateralColor curve, with lens magnification color difference correction less than 5µm.
[0071] Please refer to the optical structure of Example 2. Figure 6The specific parameters for Example 2 are shown in Tables 3 and 4 below. In Example 2, the lens focal length f' = 2.8mm, and the total optical length (TTL) of the lens is less than 22.3mm.
[0072] Table 3 Example 2 Parameter Table
[0073]
[0074]
[0075] Table 4 Example 2 Aspherical Coefficients Table
[0076]
[0077] Please see Figure 7 The MTF curve of the optical system in Example 2 shows that the MTF is greater than 0.5 across the entire field of view at 100 lp / mm. Please refer to [link / reference]. Figure 8 In Example 2, the MTF at 850nm wavelength shows a full-field MTF greater than 0.5 at 100 lp / mm. Please refer to [link / reference]. Figure 9 Example 2 shows the through-focus curve at 850nm wavelength, with an IRshift of less than 4µm. Please refer to [link / reference]. Figure 10 Example 2 shows the LateralColor curve, with lens magnification color difference correction less than 5µm.
[0078] Please refer to the optical structure of Example 3. Figure 11 The specific parameters for Example 3 are shown in Tables 5 and 6 below. In Example 3, the lens focal length f' = 2.8mm, and the total optical length (TTL) of the lens is less than 22.3mm.
[0079] Table 5 Example 3 Parameter Table
[0080]
[0081]
[0082] Table 6 Example 3 Aspherical Coefficients Table
[0083]
[0084] Please see Figure 12 The MTF curve of the optical system in Example 3 shows that the MTF is greater than 0.5 across the entire field of view at 100 lp / mm. Please refer to [link / reference]. Figure 13 In Example 3, the MTF at 850nm wavelength shows a full-field MTF greater than 0.5 at 100 lp / mm. Please refer to [link / reference]. Figure 14 Example 3 shows the through-focus curve at 850nm wavelength, with an IRshift of less than 3µm. Please refer to [link / reference]. Figure 15Example 3 shows the LateralColor curve, with lens magnification chromatic aberration correction less than 5µm.
[0085] Based on Examples 1 to 3, this case has the following advantages:
[0086] This glass-plastic confocal day / night lens employs a compact six-lens optical structure. Through the rational allocation of diopter and surface design of each lens, material and manufacturing costs are effectively reduced, while the overall lens length is significantly shortened (TTL < 22.3mm), and the effective lens diameter is less than φ11mm, resulting in a significantly smaller overall volume and meeting the requirements of miniaturized optical systems. In terms of imaging performance, the lens maintains an MTF value greater than 0.55 across the entire field of view at a high spatial frequency of 100lp / mm, ensuring excellent imaging resolution and contrast. With a target surface height greater than 6.6mm, it can be matched with a 1 / 2.7-inch image sensor, meeting high-resolution imaging requirements while also maintaining confocal optical performance day and night. By consecutively using two negative diopter lenses (the second and first lenses), the field of view is compressed and the light beam is expanded, optimizing the light path and deflecting it towards the optical axis. This effectively reduces the outer diameter of subsequent lenses, significantly reducing the size and complexity of the optical system while maintaining a large field of view. In addition, the sixth lens adopts a positive diopter design and sets its image-side surface to be convex, which optimizes the deflection path of the incident beams in each field of view, enabling them to converge efficiently on the imaging surface. This significantly suppresses spherical aberration, chromatic aberration, field curvature, and astigmatism of the optical system, thereby improving the overall imaging quality and system stability.
[0087] Example 4
[0088] For reference Figure 16 A description of electronic device A according to Example 4 of this utility model will be given. Figure 16 This is a schematic diagram of an electronic device (industrial camera) using the glass-plastic day-night confocal lens according to Examples 1 to 3 in a camera optical system.
[0089] exist Figure 16 In the figures, reference numeral A2 indicates the main body of the electronic device, and reference numeral A1 indicates a camera optical system (interchangeable lens) including a glass-plastic day / night confocal lens according to Examples 1 to 3. Reference numeral A3 indicates an image sensor (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor, which is built into the camera body A2 and receives light from the camera optical system A1 (the optical image formed by the camera optical system A1 is then photoelectric converted).
[0090] By using the glass-plastic day-night confocal lens according to Examples 1 to 3 in electronic devices such as digital still cameras, electronic devices with lenses having high optical performance can be obtained.
[0091] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the disclosed exemplary embodiments. The scope of the following claims will be given the broadest interpretation to cover all such modifications and equivalent structures and functions.
Claims
1. A glass-plastic confocal lens for day and night illumination, characterized in that, The lenses, from the object side to the image side, are in the following order: first lens, second lens, third lens, fourth lens, fifth lens, and sixth lens; The first lens has negative refractive power, the object side of the lens is convex, and the image side of the lens is concave. The second lens has negative refractive power, and the object side of the lens is concave, as is the image side of the lens. The third lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface of the lens. The fourth lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface of the lens. The fifth lens has negative refractive power. The object-side surface of the lens is concave, and the image-side surface of the lens is also concave. The sixth lens has positive refractive power, and the object-side surface of the lens is convex, as is the image-side surface of the lens. The lens satisfies the following condition: nd3 > 2.0 In the formula, nd3 is the refractive index of the third lens.
2. The glass-plastic day / night confocal lens as described in claim 1, characterized in that, An aperture stop is provided between the third lens and the fourth lens.
3. The glass-plastic day / night confocal lens as described in claim 1, characterized in that, The first lens and the third lens are glass spherical lenses, while the second lens, the fourth lens, the fifth lens, and the sixth lens are plastic aspherical lenses.
4. A glass-plastic day / night confocal lens as described in claim 3, characterized in that, The second lens, the fourth lens, and the sixth lens are made of high dispersion material; the third lens and the fifth lens are made of low dispersion material.
5. A glass-plastic day / night confocal lens as described in claim 1, characterized in that, The lens satisfies the following condition: 7.5 <TTL / f<8.5 In the formula, TTL is the total optical length of the lens, and f is the focal length of the lens.
6. An electronic device, characterized in that, A glass-plastic day / night confocal lens according to any one of claims 1-5; and An image sensor is configured to receive images formed by the glass-plastic day / night confocal lens.