A miniaturized portable ultraviolet imaging lens and its application

Abstract

This application discloses a miniaturized portable ultraviolet imaging lens and its application, relating to the field of optical imaging technology. Addressing the technical problems of existing ultraviolet imaging lenses being bulky, heavy, difficult to adapt to portable testing equipment, and having insufficient imaging resolution and low transmittance in the ultraviolet band, this invention arranges a first to a sixth lens sequentially along the optical axis from the object side to the image side, with the aperture stop positioned between the third and fourth lenses. The total optical length of the lens is ≤50mm, the overall weight is ≤30g, all six lenses are made of fused silica material, and the surface is coated with an ultraviolet anti-reflection film. The lens transmittance in the ultraviolet band is ≥85%. This invention, through the reasonable optical power configuration of the six lenses and the selection of fused silica material, achieves miniaturization, lightweight design, and high transmittance of the ultraviolet imaging lens, facilitating integration into portable testing equipment and meeting the needs of on-site mobile testing.

Description

Technical Field

[0001] This application relates to a miniaturized portable ultraviolet imaging lens and its application, belonging to the field of optical imaging technology. Background Technology

[0002] Ultraviolet (UV) imaging technology, as an important optical detection method, has wide applications in various fields such as criminal investigation, environmental monitoring, medical diagnosis, and industrial inspection. As the core optical component of UV detection equipment, the UV imaging lens's main function is to converge the UV light signal emitted or reflected by the target object onto the imaging sensor to form a clear UV image. Currently, most UV imaging lens designs in the industry are based on improvements to the optical structure of traditional visible light lenses. They typically employ multi-lens optical systems, with lens materials primarily consisting of optical glass or special UV-transmitting materials. Some designs use cemented lens groups or aspherical lenses to correct aberrations. In terms of application scenarios, existing UV lenses are mainly designed for industrial-grade fixed inspection equipment, emphasizing optical performance stability and image quality. They generally contain eight or more lenses, have a relatively long optical length, and a relatively complex overall structure.

[0003] However, the current problem is that most existing ultraviolet imaging lenses are industrial-grade designs, with numerous lenses, large size, and heavy weight, making them difficult to adapt to the miniaturization and lightweight requirements of portable inspection equipment. At the same time, existing portable ultraviolet lenses have limitations in imaging performance, exhibiting insufficient imaging resolution, significant distortion, and low transmittance in the ultraviolet band, failing to meet the requirements of high-precision on-site inspection. Furthermore, some ultraviolet lenses use cemented lenses or aspherical lens structures, which, while improving optical performance, involve complex manufacturing processes and high costs, hindering the large-scale popularization and promotion of portable ultraviolet inspection equipment.

[0004] Therefore, how to design an ultraviolet imaging lens that combines miniaturization, lightweight design, and high imaging performance has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This invention relates to a miniaturized portable ultraviolet imaging lens and its application. The technical problem to be solved by this invention is that most existing ultraviolet imaging lenses are industrial-grade designs with a large number of lenses, large size, and heavy weight, which makes it difficult to adapt to the miniaturization and weight reduction requirements of portable detection equipment. At the same time, existing portable ultraviolet lenses have limitations in imaging performance, such as insufficient imaging resolution, large distortion, and low transmittance in the ultraviolet band, which cannot meet the requirements of high-precision on-site detection.

[0006] To achieve the above objectives, this application provides the following technical solution: A miniaturized portable ultraviolet imaging lens is provided, wherein a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, and a sixth lens are arranged sequentially along the optical axis from the object side to the image side; The total optical length of the ultraviolet imaging lens is ≤50mm, and the overall weight is ≤30g; The first to sixth lenses are all made of fused silica material and are all coated with an ultraviolet anti-reflection film. The aperture stop is positioned between the third lens and the fourth lens; The ultraviolet imaging lens has a transmittance of ≥85% in the ultraviolet band.

[0007] Optionally, the first lens is a negative optical power biconcave spherical lens, with the object plane side being concave and the image plane side being concave. The second lens is a biconvex spherical lens with positive optical power, having a convex surface on both the object and image sides; The third lens is a negative optical power curved moon lens, with a convex surface on the object side and a concave surface on the image side; Preferably, the fourth lens is a biconvex spherical lens with positive optical power, having a convex surface on both the object plane and image plane sides; The fifth lens is a negative optical power biconcave spherical lens, with a concave surface on both the object and image sides. The sixth lens is a positive optical power curved moon lens, with a concave surface on the object side and a convex surface on the image side.

[0008] Optionally, the wavelength range of the ultraviolet antireflective film is 280nm-400nm, and the transmittance of the ultraviolet imaging lens in the 300nm-380nm band is ≥85%.

[0009] Optionally, the aperture of the aperture stop is 2-3 mm; The ultraviolet imaging lens has a focal length of 15-20mm and a numerical aperture of 0.2-0.3.

[0010] Optionally, the distortion of the ultraviolet imaging lens is ≤0.2%, and the MTF curve value at 50 line pairs / mm is ≥0.6.

[0011] Optionally, the refractive index Nd of the first lens to the sixth lens is 1.46 and the dispersion coefficient Vd is 67.8.

[0012] Optionally, the ultraviolet imaging lens has an optical length of 45mm, an overall weight of 25g, a focal length of 18mm, and a numerical aperture of 0.25.

[0013] Optionally, the center thickness of the first lens is 2-3 mm, and the focal length is -30 mm to -40 mm; The second lens has a center thickness of 2.5-3.5 mm and a focal length of 25-32 mm. The center thickness of the third lens is 2-2.5mm, and the focal length is -40mm to -45mm; Preferably, the center thickness of the fourth lens is 2.5-3.2 mm, and the focal length is 20-25 mm; The fifth lens has a center thickness of 2-2.6 mm and a focal length of -35 mm to -42 mm. The sixth lens has a center thickness of 2.3-3.0 mm and a focal length of 28-35 mm.

[0014] Optionally, the ultraviolet imaging lens further includes a lens barrel and an imaging surface, wherein the first to sixth lenses are fixedly installed inside the lens barrel, and the imaging surface is disposed on the image side of the sixth lens.

[0015] Optionally, the ultraviolet imaging lens is suitable for portable ultraviolet detection equipment, on-site criminal investigation evidence collection equipment, or outdoor ultraviolet monitoring equipment.

[0016] The beneficial effects that this application can produce include: 1) This application adopts a six-lens optical structure design. By reasonably configuring the optical power and surface shape of each lens, the number of lenses is effectively reduced while ensuring imaging quality. The total optical length of the lens is controlled within 50mm and the overall weight does not exceed 30g. This achieves the miniaturization and lightweighting of the ultraviolet imaging lens, making it easy to integrate into portable detection equipment and meet the needs of on-site mobile detection.

[0017] 2) All lenses in this application are made of fused silica material, which has excellent transmittance in the ultraviolet band. Combined with the ultraviolet antireflection coating coated on the surface, the transmittance of the lens in the ultraviolet band reaches more than 85%, which effectively improves the acquisition efficiency of ultraviolet light signals and ensures the clarity and signal-to-noise ratio of the image.

[0018] 3) This application sets the aperture stop between the third and fourth lenses. By optimizing the position of the aperture stop, the incident angle of light from each lens is effectively balanced, the system aberration is reduced, the lens distortion is controlled within 0.2%, and the MTF curve at 50 line pairs / mm reaches a value of more than 0.6, which significantly improves the imaging resolution and image quality and meets the application requirements of high-precision ultraviolet detection.

[0019] 4) All lenses in this application adopt a spherical design. Compared with aspherical or cemented lens solutions, the processing technology is simple and the manufacturing cost is low, which is conducive to the large-scale production and market promotion of portable ultraviolet imaging lenses. At the same time, the alternating positive and negative optical power of the six lenses effectively corrects chromatic aberration and spherical aberration, ensuring imaging consistency in the ultraviolet band. Attached Figure Description

[0020] Figure 1 A schematic diagram of the optical structure of a miniaturized portable ultraviolet imaging lens provided in one embodiment of this application; Figure label: 10-Ultraviolet imaging lens; 11-First lens; 12-Second lens; 13-Third lens; 14-Aperture stop; 15-Fourth lens; 16-Fifth lens; 17-Sixth lens; 18-Lens barrel; 19-Image plane. Detailed Implementation

[0021] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] To address the problems of existing ultraviolet imaging lenses being bulky, heavy, and difficult to adapt to portable detection equipment, this application provides a miniaturized portable ultraviolet imaging lens and its application.

[0023] Please refer to Figure 1 As shown, a miniaturized portable ultraviolet imaging lens is provided, comprising a first lens 11, a second lens 12, a third lens 13, an aperture stop 14, a fourth lens 15, a fifth lens 16, and a sixth lens 17 arranged sequentially along the optical axis from the object side to the image side; the total optical length of the ultraviolet imaging lens 10 is ≤50mm, and the overall weight is ≤30g; the first lens 11 to the sixth lens 17 are all made of fused silica material, and their surfaces are all coated with an ultraviolet antireflection film; the aperture stop 14 is disposed between the third lens 13 and the fourth lens 15; the transmittance of the ultraviolet imaging lens 10 in the ultraviolet band is ≥85%.

[0024] It should be noted that the first lens 11 to the sixth lens 17 are optical glass elements, arranged sequentially along the optical axis. Adjacent lenses are positioned and fixed by limiting steps within the lens barrel 18. The total optical length refers to the distance from the vertex of the object-side surface of the first lens 11 to the imaging surface 19, and is limited to within 50mm by controlling the thickness of each lens and the air gap. The overall weight includes the total mass of all lenses, the lens barrel 18, and the fixing components, and is controlled to within 30g by using lightweight materials and a simplified structure. The fused silica material is an optical material with a silicon dioxide content ≥99.9%, exhibiting excellent ultraviolet transmittance. The ultraviolet antireflective coating is fabricated using a multilayer dielectric film deposition process, with film materials including magnesium fluoride and silicon dioxide. The aperture stop 14 is a circular light-passing hole structure, mechanically machined and installed inside the lens barrel 18. This structure achieves convergence imaging of ultraviolet light through the rational arrangement of six lenses. The light enters from the object side, is refracted sequentially by the six lenses, and then converges onto the imaging surface.

[0025] The above-mentioned simplified structure of six lenses combined with fused silica material achieves miniaturization and weight reduction of the ultraviolet imaging lens 10. The total optical length is controlled within 50mm and the overall weight does not exceed 30g, which makes it easy to integrate into portable detection equipment and meet the needs of on-site mobile detection. At the same time, the transmittance of the ultraviolet band reaches more than 85%, which effectively improves the acquisition efficiency of ultraviolet light signals.

[0026] To address the problem of significant aberrations caused by the unreasonable configuration of lens surfaces and optical power in existing ultraviolet imaging lenses, this application further optimizes the structure of the first three lenses.

[0027] Please refer to Figure 1 As shown, the first lens 11 is a negative optical power biconcave spherical lens with a concave surface on both the object and image sides; the second lens 12 is a positive optical power biconvex spherical lens with a convex surface on both the object and image sides; and the third lens 13 is a negative optical power crescent-shaped lens with a convex surface on both the object and image sides.

[0028] It should be noted that negative optical power refers to a lens that diverges light, with a negative focal length. Positive optical power refers to a lens that converges light, with a positive focal length. A biconcave spherical lens is a spherical lens with two concave surfaces, formed through grinding and polishing. A biconvex spherical lens is a spherical lens with two convex surfaces, formed through grinding and polishing. A crescent-shaped spherical lens is a spherical lens with one convex surface and the other concave, with different radii of curvature. The object plane side refers to the side facing the object being photographed, and the image plane side refers to the side facing the imaging sensor. These three lenses together constitute the front optical system of the ultraviolet imaging lens 10. The first lens 11 initially diverges the incident light, the second lens 12 converges the light, and the third lens 13 further diverges the light and corrects aberrations.

[0029] By employing an alternating configuration of negative, positive, and negative optical power, the spherical aberration and coma of the system are effectively corrected, reducing the overall aberration of the optical system and improving imaging quality. At the same time, the spherical design facilitates processing and manufacturing, reducing production costs.

[0030] To address the problem of insufficient imaging resolution caused by the unreasonable configuration of the rear lens group in existing ultraviolet imaging lenses, this application further optimizes the structure of the rear three lenses.

[0031] Please refer to Figure 1 As shown, the fourth lens 15 is a positive optical power biconvex spherical lens with a convex surface on both the object and image sides; the fifth lens 16 is a negative optical power biconcave spherical lens with a concave surface on both the object and image sides; and the sixth lens 17 is a positive optical power crescent moon lens with a concave surface on both the object and image sides.

[0032] It should be noted that the biconvex spherical structure of the fourth lens 15 is formed through a grinding and polishing process, and the radii of curvature of the two convex surfaces can be the same or different. The biconcave spherical structure of the fifth lens 16 is formed through a grinding and polishing process, and the radii of curvature of the two concave surfaces can be the same or different. The crescent-shaped structure of the sixth lens 17 is formed through a grinding and polishing process, and the radii of curvature of the concave and convex surfaces are determined according to the optical design. These three lenses together constitute the rear optical system of the lens, working in conjunction with the first three lenses to achieve light convergence and aberration correction.

[0033] By employing an alternating configuration of positive and negative optical power, the field curvature and distortion of the system are effectively corrected, allowing light to converge accurately onto the imaging surface, thus improving imaging resolution and image edge sharpness. At the same time, it forms a symmetrical optical structure with the first three lenses, which is beneficial for system assembly and alignment.

[0034] To address the issue of low transmittance in the ultraviolet band of existing ultraviolet imaging lenses, this application further optimizes the antireflection coating and transmittance parameters.

[0035] Please refer to Figure 1 As shown, the wavelength range of the ultraviolet antireflective film is 280nm-400nm, and the transmittance of the ultraviolet imaging lens 10 in the 300nm-380nm band is ≥85%.

[0036] It should be noted that the UV antireflective coating is prepared using a vacuum deposition process, and the film thickness is optimized according to the target wavelength, typically with a single layer thickness of one-quarter of the wavelength. The wavelength range of UV light is 280nm-400nm, covering near-UV and part of the mid-UV band. 300nm-380nm is the commonly used operating band for UV detection, where transmittance requirements are more stringent. Transmittance refers to the ratio of incident light energy to emitted light energy, measured using a spectrometer. The antireflective coating is deposited on both surfaces of the lens using electron beam evaporation or ion-assisted deposition processes.

[0037] This antireflection coating structure reduces reflection loss on the lens surface and improves the transmittance of ultraviolet light, enabling the lens to achieve a transmittance of over 85% in the 300nm-380nm wavelength range. This effectively improves the acquisition efficiency of ultraviolet light signals, ensures the clarity and signal-to-noise ratio of the image, and meets the performance requirements of ultraviolet detection equipment.

[0038] To address the problem of unstable imaging quality caused by unreasonable optical parameter design in existing ultraviolet imaging lenses 10, this application further optimizes the aperture stop 14 and the lens optical parameters.

[0039] Please refer to Figure 1 As shown, the aperture stop 14 has an aperture of 2-3 mm; the ultraviolet imaging lens 10 has a focal length of 15-20 mm and a numerical aperture of 0.2-0.3.

[0040] It should be noted that the aperture of the aperture stop 14 refers to the diameter of the light-passing aperture, which is controlled to a tolerance within ±0.05mm through precision machining. The focal length refers to the distance from the principal point of the lens to the focal point, which is determined through optimization using optical design software. The numerical aperture refers to the parameter of the lens's ability to collect light, which is equal to the refractive index multiplied by the sine of the aperture angle. The aperture stop 14 is located inside the lens barrel 18 and its position is fixed by a positioning ring. This parameter configuration gives the ultraviolet imaging lens 10 a moderate amount of light and an imaging field of view. The focal length of 15-20mm is suitable for close-range ultraviolet detection applications, the numerical aperture of 0.2-0.3 ensures sufficient light intake and depth of field, and the aperture of 2-3mm balances imaging brightness and aberration control, enabling the ultraviolet imaging lens 10 to have stable imaging performance in portable application scenarios.

[0041] To address the issues of significant image distortion and insufficient resolution in existing ultraviolet imaging lenses, this application further optimizes the optical performance indicators of the lens.

[0042] Please refer to Figure 1 As shown, the distortion of the ultraviolet imaging lens 10 is ≤0.2%, and the MTF curve value at 50 line pairs / mm is ≥0.6.

[0043] It should be noted that distortion refers to the percentage deviation between the actual image height and the ideal image height, which is optimized and controlled through optical design software. The MTF curve, or Modulation Transfer Function curve, reflects the lens's ability to transmit different spatial frequencies. 50 line pairs / mm is a medium spatial frequency used to evaluate the lens's imaging resolution. A value ≥0.6 indicates that the lens has good contrast transmission capabilities at that frequency. Distortion is corrected through optimization of lens shape and aperture stop position, while MTF is improved through lens material selection and optical power configuration.

[0044] These performance indicators enable the ultraviolet imaging lens 10 to have low image distortion and high imaging resolution, ensuring the geometric accuracy and detail clarity of ultraviolet images, and meeting the requirements of high-precision detection applications such as criminal investigation and environmental monitoring.

[0045] To address the issue of unstable image quality caused by the unstable material properties of existing ultraviolet imaging lenses 10, this application further optimizes the lens material parameters.

[0046] Please refer to Figure 1 As shown, the refractive index Nd of the first lens 11 to the sixth lens 17 is 1.46, and the dispersion coefficient Vd is 67.8.

[0047] It should be noted that refractive index Nd refers to a material's ability to refract light at a specific wavelength; the refractive index of fused silica at a wavelength of 587.6 nm is approximately 1.46. Dispersion coefficient Vd measures the change in refractive index of a material for different wavelengths of light; the dispersion coefficient of fused silica is approximately 67.8. All six lenses use fused silica material from the same batch, verified by optical parameter testing reports provided by the material supplier. Material consistency is ensured by procuring optical blanks from the same fusion batch.

[0048] The material parameter configuration enables the six lenses to have uniform optical performance, reducing chromatic aberration and aberration caused by material differences, ensuring imaging consistency in the ultraviolet band, while the fused silica material has stable transmittance in the ultraviolet band and is not prone to aging and deterioration with long-term use.

[0049] In view of the problem that the size and weight parameters of the existing ultraviolet imaging lens 10 are not specific enough, this application further optimizes the parameters of the specific embodiment of the lens.

[0050] Please refer to Figure 1 As shown, the ultraviolet imaging lens 10 has an optical length of 45mm, an overall weight of 25g, a focal length of 18mm, and a numerical aperture of 0.25.

[0051] It should be noted that the total optical length of 45mm was calculated by summing the thicknesses of each lens and the air gaps. Specifically, the thickness of the first lens 11 is 2.5mm, the air gap is 3mm; the thickness of the second lens 12 is 3mm, the air gap is 2.5mm; the thickness of the third lens 13 is 2.2mm, the air gap is 4mm; the thickness of the fourth lens 15 is 2.8mm, the air gap is 3.5mm; the thickness of the fifth lens 16 is 2.3mm, the air gap is 3.5mm; the thickness of the sixth lens 17 is 2.7mm, and the back cutoff is 13mm. The overall weight of 25g was calculated based on the material density and volume; the density of fused silica is approximately 2.2g / cm³. The focal length of 18mm was determined through optimization using optical design software. The numerical aperture of 0.25 was calculated using the aperture stop 14 and the focal length.

[0052] This specific parameter configuration is a preferred embodiment of the lens, achieving a balance between miniaturization, lightweighting, and high imaging performance. The total optical length and weight are both better than the upper limit requirements, providing a specific design reference for portable ultraviolet detection devices.

[0053] To address the issue that the size parameters of the 10 lenses in existing ultraviolet imaging lenses are not specific enough, this application further optimizes the thickness and focal length of the first three lenses.

[0054] Please refer to Figure 1 As shown, the center thickness of the first lens 11 is 2-3mm, and the focal length is -30mm to -40mm; the center thickness of the second lens 12 is 2.5-3.5mm, and the focal length is 25-32mm; the center thickness of the third lens 13 is 2-2.5mm, and the focal length is -40mm to -45mm.

[0055] It should be noted that the center thickness refers to the thickness at the optical axis of the lens, and the tolerance is controlled within ±0.02mm through precision grinding. The focal length is calculated based on the lens's radius of curvature, thickness, and material refractive index. The negative focal length of the first lens 11 causes it to diverge light, the positive focal length of the second lens 12 causes it to converge light, and the negative focal length of the third lens 13 causes it to diverge light again. The thickness and focal length range of the three lenses are determined through optical design optimization, controlling the lens volume while ensuring image quality.

[0056] This parameter configuration enables the three front lenses to have a reasonable distribution of optical power, effectively corrects the spherical aberration and coma of the system, and controls the size and weight of the lenses, providing specific parameter support for the miniaturization design of the lens.

[0057] To address the issue that the dimensions of the three rear lenses in existing ultraviolet imaging lenses are not specific enough, this application further optimizes the thickness and focal length of the three rear lenses.

[0058] Please refer to Figure 1 As shown, the center thickness of the fourth lens 15 is 2.5-3.2mm, and the focal length is 20-25mm; the center thickness of the fifth lens 16 is 2-2.6mm, and the focal length is -35mm to -42mm; the center thickness of the sixth lens 17 is 2.3-3.0mm, and the focal length is 28-35mm.

[0059] It should be noted that the center thickness is controlled to a tolerance within ±0.02mm through precision grinding. The focal length is calculated based on the lens's radius of curvature, thickness, and material refractive index. The positive focal length of the fourth lens 15 causes it to converge light, the negative focal length of the fifth lens 16 causes it to diverge light, and the positive focal length of the sixth lens 17 causes it to converge light. The thickness and focal length range of the three lenses are determined through optical design optimization, controlling the lens volume while ensuring image quality.

[0060] This parameter configuration enables the rear three lenses to have a reasonable distribution of optical power, effectively correcting the field curvature and distortion of the system. At the same time, it forms a symmetrical optical structure with the front three lenses, providing specific parameter support for the lens's high-resolution imaging.

[0061] To address the issue of insufficient structural integrity in existing ultraviolet imaging lenses 10, this application further optimizes the overall structure of the lens.

[0062] Please refer to Figure 1 As shown, the ultraviolet imaging lens 10 also includes a lens barrel 18 and an imaging surface 19. The first lens 11 to the sixth lens 17 are fixedly installed inside the lens barrel 18, and the imaging surface 19 is disposed on the image side of the sixth lens 17.

[0063] It should be noted that the lens barrel 18 is a cylindrical or elliptical metal structure made of aluminum alloy or stainless steel, and is CNC machined. Multiple limiting steps are provided on the inner wall for lens positioning. The lens is connected to the lens barrel 18 using a pressure ring, which is made of aluminum alloy and connected to the lens barrel 18 via threads. The imaging surface 19 is the photosensitive surface of the image sensor, located at the back focal length position on the image side of the sixth lens 17, and perpendicularly aligned with the lens optical axis. The outer surface of the lens barrel 18 has mounting threads for connection to testing equipment.

[0064] This structural configuration provides a stable mounting position for the six lenses, the lens barrel 18 provides mechanical protection and optical path shielding, and the precise alignment of the imaging surface 19 with the lens ensures image quality. The overall structure is compact and reliable, making it easy to integrate into portable ultraviolet detection equipment.

[0065] In response to the problem of unclear application scenarios for existing ultraviolet imaging lenses, this application further clarifies the application areas of the lenses.

[0066] Specifically, the ultraviolet imaging lens 10 is suitable for portable ultraviolet detection equipment, on-site criminal investigation evidence collection equipment, or outdoor ultraviolet monitoring equipment.

[0067] Understandably, portable ultraviolet (UV) detection equipment refers to handheld or shoulder-mounted UV imaging instruments, typically weighing less than 2 kg. On-site criminal investigation evidence collection equipment refers to specialized equipment used for UV trace detection at crime scenes, requiring rapid deployment and mobility. Outdoor UV monitoring equipment refers to UV imaging instruments used in outdoor scenarios such as environmental monitoring and power supply inspection, needing to adapt to various environmental conditions. The miniaturization and lightweight design of the lenses enable their integration into the aforementioned equipment, meeting the needs of mobile detection.

[0068] This application specification clarifies the usage scenarios of the ultraviolet imaging lens 10, provides a technical reference for the system integration of the device, and demonstrates the practical application value of the technical solution of this application.

[0069] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A miniaturized portable ultraviolet imaging lens, characterized in that, Along the optical axis from the object side to the image side, a first lens (11), a second lens (12), a third lens (13), an aperture stop (14), a fourth lens (15), a fifth lens (16), and a sixth lens (17) are arranged in sequence. The total optical length of the ultraviolet imaging lens (10) is ≤50mm and the total weight is ≤30g; The first lens (11) to the sixth lens (17) are all made of fused silica material and are coated with an ultraviolet anti-reflective film on their surfaces; The aperture stop (14) is disposed between the third lens (13) and the fourth lens (15); The ultraviolet imaging lens (10) has a transmittance of ≥85% in the ultraviolet band.

2. The miniaturized portable ultraviolet imaging lens according to claim 1, characterized in that, The first lens (11) is a negative optical power biconcave spherical lens, with the object side being concave and the image side being concave. The second lens (12) is a biconvex spherical lens with positive optical power, with a convex surface on the object side and a convex surface on the image side; The third lens (13) is a negative optical power curved moon lens, with a convex surface on the object side and a concave surface on the image side; Preferably, the fourth lens (15) is a biconvex spherical lens with positive optical power, the object side being convex and the image side being convex; The fifth lens (16) is a negative optical power biconcave spherical lens, with the object side being concave and the image side being concave. The sixth lens (17) is a positive optical power curved moon lens with a concave surface on the object side and a convex surface on the image side.

3. The miniaturized portable ultraviolet imaging lens according to claim 1, characterized in that, The wavelength range of the ultraviolet antireflective film is 280nm-400nm, and the transmittance of the ultraviolet imaging lens (10) in the 300nm-380nm band is ≥85%.

4. The miniaturized portable ultraviolet imaging lens according to claim 1, characterized in that, The aperture of the aperture stop (14) is 2-3 mm; The ultraviolet imaging lens (10) has a focal length of 15-20mm and a numerical aperture of 0.2-0.

3.

5. The miniaturized portable ultraviolet imaging lens according to claim 1, characterized in that, The distortion of the ultraviolet imaging lens (10) is ≤0.2%, and the MTF curve value at 50 line pairs / mm is ≥0.

6.

6. The miniaturized portable ultraviolet imaging lens according to claim 1, characterized in that, The refractive index Nd of the first lens (11) to the sixth lens (17) is 1.46 and the dispersion coefficient Vd is 67.

8.

7. The miniaturized portable ultraviolet imaging lens according to claim 1, characterized in that, The ultraviolet imaging lens (10) has an optical length of 45mm, an overall weight of 25g, a focal length of 18mm, and a numerical aperture of 0.

25.

8. The miniaturized portable ultraviolet imaging lens according to claim 1, characterized in that, The center thickness of the first lens (11) is 2-3 mm, and the focal length is -30 mm to -40 mm; The center thickness of the second lens (12) is 2.5-3.5 mm, and the focal length is 25-32 mm; The center thickness of the third lens (13) is 2-2.5mm, and the focal length is -40mm to -45mm; Preferably, the center thickness of the fourth lens (15) is 2.5-3.2 mm, and the focal length is 20-25 mm; The center thickness of the fifth lens (16) is 2-2.6 mm, and the focal length is -35 mm to -42 mm; The center thickness of the sixth lens (17) is 2.3-3.0 mm, and the focal length is 28-35 mm.

9. The miniaturized portable ultraviolet imaging lens according to claim 1, characterized in that, The ultraviolet imaging lens (10) also includes a lens barrel (18) and an imaging surface (19). The first lens (11) to the sixth lens (17) are fixedly installed inside the lens barrel (18), and the imaging surface (19) is disposed on the image side of the sixth lens (17).

10. The miniaturized portable ultraviolet imaging lens according to claim 1, characterized in that, The ultraviolet imaging lens (10) is suitable for portable ultraviolet detection equipment, on-site criminal investigation and evidence collection equipment or outdoor ultraviolet monitoring equipment.

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