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CN-122018123-A - Double telecentric ultraviolet security monitoring lens

CN122018123ACN 122018123 ACN122018123 ACN 122018123ACN-122018123-A

Abstract

The application discloses a double telecentric ultraviolet security monitoring lens, and relates to the technical field of optical lenses. The application sequentially arranges a dustproof and waterproof window, a front lens group, a beam splitter prism, an aperture diaphragm, a rear lens group and an imaging surface from an object side to an image side along an optical axis. The lens adopts a double telecentric structure, telecentricity of the object side and the image side is less than or equal to 0.2 degrees, parallel light paths are arranged between the front lens group and the rear lens group, and light parallelism is less than or equal to 0.1 degrees. The dustproof and waterproof window is made of a sapphire material and is plated with a hydrophobic and antifouling film, and the lens is made of a fused quartz material and is plated with an ultraviolet antireflection film. The application ensures imaging dimensional stability through the double telecentric optical structure, the parallel light path is convenient for inserting the light splitting element to realize real-time monitoring of ultraviolet light beams, the protection design enables the lens to have IP67 protection level, the ultraviolet antireflection film improves the wave band transmittance of 300nm-400nm to more than 85%, and the application is suitable for outdoor ultraviolet security monitoring, high-voltage circuit arc detection and camouflage target identification scenes.

Inventors

  • LI BINGXUAN
  • ZHANG GE

Assignees

  • 闽都创新实验室

Dates

Publication Date
20260512
Application Date
20260326

Claims (10)

  1. 1. The double telecentric ultraviolet security monitoring lens is characterized in that a dustproof and waterproof window (1), a front lens group (2), a beam splitting prism (3), an aperture diaphragm (4), a rear lens group (5) and an imaging surface (6) are sequentially arranged from an object side to an image side along an optical axis; the lens adopts a double telecentric structure, telecentricity of an object side and an image side is less than or equal to 0.2 degrees, a parallel light path is arranged between the front lens group (2) and the rear lens group (5), and light parallelism of the parallel light path is less than or equal to 0.1 degrees.
  2. 2. The double telecentric ultraviolet security monitoring lens according to claim 1, wherein the front lens group (2) comprises a first lens (21), a second lens (22), a third lens (23) and a fourth lens (24) which are arranged in sequence from an object side to an image side; the first lens (21) is a biconcave spherical lens with negative focal power, the second lens (22) is a meniscus lens with negative focal power, the third lens (23) is a biconvex spherical lens with positive focal power, and the fourth lens (24) is a meniscus lens with positive focal power.
  3. 3. The double telecentric ultraviolet security monitoring lens according to claim 2, wherein the rear lens group (5) comprises a fifth lens (51), a sixth lens (52), a seventh lens (53) and an eighth lens (54) arranged in order from the object side to the image side; the fifth lens (51) is a biconvex spherical lens with positive focal power, the sixth lens (52) is a biconcave spherical lens with negative focal power, the seventh lens (53) is a biconvex spherical lens with positive focal power, and the eighth lens (54) is a meniscus lens with negative focal power; Preferably, the refractive index nd=1.45-1.48 and the dispersion coefficient vd=65-70 of the first to eighth lenses (21, 54).
  4. 4. The double telecentric ultraviolet security monitoring lens according to claim 1, characterized in that the dustproof and waterproof window (1) is made of sapphire, and the surface is plated with a hydrophobic and antifouling film; the first lens (21) to the eighth lens (54) are made of fused quartz materials, and the surfaces of the first lens and the eighth lens are plated with ultraviolet antireflection films; Preferably, the wavelength range of the ultraviolet antireflection film is 300nm-400nm, and the transmittance is more than or equal to 85%; Preferably, the thickness of the dustproof and waterproof window (1) is 3mm-5mm, the refractive index Nd=1.75-1.80, and the dispersion coefficient Vd=75-80.
  5. 5. The double telecentric ultraviolet security monitoring lens according to claim 1, characterized in that the beam splitting prism (3) is arranged between the front lens group (2) and the aperture stop (4) for monitoring the ultraviolet light beam and capturing abnormal signals; Preferably, the aperture of the aperture diaphragm (4) is 3mm-5mm, and the aperture diaphragm is positioned between the beam splitting prism (3) and the rear lens group (5).
  6. 6. The double telecentric ultraviolet security monitoring lens according to claim 1, wherein the effective field of view of the object side of the lens is more than or equal to 60mm, the effective field of view of the image side is more than or equal to 30mm, the numerical aperture is 0.15-0.25, the distortion is less than or equal to 0.1%, and the total optical length is 80-90mm; Preferably, the distortion is less than or equal to 0.08%; preferably, the lens has an IP67 dustproof and waterproof grade, and is suitable for outdoor ultraviolet security monitoring, high-voltage circuit arc detection or camouflage target identification scenes.
  7. 7. The double telecentric ultraviolet security monitoring lens according to claim 2, characterized in that the focal length of the first lens (21) is-120 mm to-130 mm, and the central thickness is 2.5mm-3.5mm; The focal length of the second lens (22) is-140 mm to-160 mm, and the center thickness is 2.5mm-3.5mm; The focal length of the third lens (23) is 170mm-190mm, and the center thickness is 3.5mm-4.5mm; The focal length of the fourth lens (24) is 150-170 mm, and the center thickness is 3.0-4.0 mm.
  8. 8. A double telecentric ultraviolet security monitoring lens according to claim 3, characterized in that the focal length of the fifth lens (51) is 300mm-340mm, and the central thickness is 3.5mm-4.5mm; The focal length of the sixth lens (52) is-90 mm to-100 mm, and the center thickness is 2.0mm-3.0mm; The focal length of the seventh lens (53) is 270mm-290mm, and the center thickness is 3.0mm-4.0mm; The focal length of the eighth lens (54) is-210 mm to-230 mm, and the center thickness is 2.5mm-3.5mm.
  9. 9. The double telecentric ultraviolet security monitoring lens according to claim 1, wherein telecentricity of the object side and the image side is less than or equal to 0.15 °, and light parallelism of the parallel light paths is less than or equal to 0.08 °.
  10. 10. The double telecentric ultraviolet security monitoring lens according to claim 1, wherein the imaging surface (6) is an ultraviolet sensitive detector target surface, and the distance between the imaging surface and the image side end surface of the rear lens group (5) is 5mm-15mm.

Description

Double telecentric ultraviolet security monitoring lens Technical Field The application relates to a double telecentric ultraviolet security monitoring lens, and belongs to the technical field of optical lenses. Background In the field of security monitoring, ultraviolet imaging technology is widely applied to special scenes such as high-voltage circuit arc detection, camouflage target identification and the like due to the sensitivity characteristic of ultraviolet imaging technology to light rays with specific wavelengths. The performance of the ultraviolet monitoring lens as a core optical component of an ultraviolet imaging system directly influences the imaging quality and the detection precision. At present, the ultraviolet security monitoring lens commonly adopted in the industry is mainly of a common telecentric structure or a non-telecentric structure, and the lens has a certain application foundation in the fields of industrial detection and scientific research. Meanwhile, the double telecentric optical structure is used as a high-precision imaging scheme, and is applied to fields with high requirements on imaging stability, such as industrial photoetching, precise measurement, 3D printing and the like, and the double telecentric optical structure can effectively reduce magnification fluctuation caused by object distance change by keeping telecentric characteristics on both an object side and an image side. However, the existing ultraviolet security monitoring lens has the problems that the telecentricity control precision is insufficient, the requirement of outdoor large-scale monitoring on imaging stability is difficult to meet, the angle of view is small, the distortion correction capability is limited, and the imaging quality is easily affected in a complex environment. In addition, the existing double telecentric ultraviolet lens is mainly designed for industrial indoor environments, has complex structure, huge volume and higher manufacturing cost, lacks protection design for outdoor severe environments, does not have dustproof and waterproof functions, and is difficult to adapt to the use requirements of outdoor security monitoring scenes. Meanwhile, the prior art scheme has limitations in the aspects of optical material selection and film coating technology of ultraviolet bands, has low ultraviolet transmittance, influences detection sensitivity and signal capturing capacity, and cannot effectively meet the comprehensive requirements of security monitoring applications such as high-voltage circuit arc detection, camouflage target identification and the like on high imaging quality and environmental adaptability. Disclosure of Invention The technical problems to be solved by the application are that the existing ultraviolet security monitoring lens is insufficient in telecentricity control precision, is difficult to meet the requirement of outdoor large-scale monitoring on imaging stability, has smaller angle of view and limited distortion correction capability, so that imaging quality is easily affected in a complex environment, and meanwhile, the existing double telecentric ultraviolet lens lacks protection design for outdoor severe environment, does not have dustproof and waterproof functions, has low ultraviolet transmittance, and affects detection sensitivity and signal capturing capability. In order to achieve the above object, the present application provides the following technical solutions: the application provides a double telecentric ultraviolet security monitoring lens, which is sequentially provided with a dustproof and waterproof window, a front lens group, a beam splitting prism, an aperture diaphragm, a rear lens group and an imaging surface along an optical axis from an object side to an image side; the lens adopts a double telecentric structure, telecentricity of an object side and an image side is less than or equal to 0.2 degrees, parallel light paths are arranged between the front lens group and the rear lens group, and light parallelism of the parallel light paths is less than or equal to 0.1 degrees. Optionally, the front lens group includes a first lens, a second lens, a third lens, and a fourth lens sequentially disposed from an object side to an image side; The first lens is a biconcave spherical lens with negative focal power, the second lens is a meniscus lens with negative focal power, the third lens is a biconvex spherical lens with positive focal power, and the fourth lens is a meniscus lens with positive focal power. Optionally, the rear lens group includes a fifth lens, a sixth lens, a seventh lens, and an eighth lens disposed in order from an object side to an image side; The fifth lens is a biconvex spherical lens with positive focal power, the sixth lens is a biconcave spherical lens with negative focal power, the seventh lens is a biconvex spherical lens with positive focal power, and the eighth lens is a meniscus lens with negative focal power; preferabl