Ultraviolet photographing equipment for investigation
By designing a four-group ultraviolet imaging objective lens, the problems of decreased imaging quality and increased equipment weight caused by photomultiplier tubes were solved, achieving high-quality, stable and economical imaging results.
Patent Information
- Application Number
- CN202520225571.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-13
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2035-02-13
AI Technical Summary
In existing ultraviolet imaging equipment, photomultiplier tubes suffer from decreased sensitivity, large size and weight, limited operating environment, short lifespan and high cost, which affect imaging quality and overall equipment performance.
The ultraviolet photographic objective lens adopts a four-group imaging lens structure, including a first imaging lens group, a second imaging lens group, a third imaging lens group, and a fourth imaging lens group. These lens groups filter and concentrate light, and combined with a CCD detector, high-quality imaging is achieved, eliminating the need for a photomultiplier tube.
It improves image quality, reduces equipment size and weight, extends lens life, lowers costs, and adds exposure compensation functionality to stabilize imaging results.
Smart Images
Figure CN223693953U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a camera technical field, concretely relates to a ultraviolet photographic equipment for investigation. BACKGROUND
[0002] Compared with visible light photographic technology, ultraviolet photographic technology can effectively record the brightness distribution of the light reflected by the object in the ultraviolet light band. Because the reflection properties of the object in the ultraviolet light band are very different from those in the visible light band, the specific details of the object can be more clearly and effectively photographed by using ultraviolet photographic technology, which cannot be achieved by ordinary photographic equipment. Therefore, ultraviolet photographic technology has a very wide application in the field of investigation.
[0003] Some faint traces, such as footprints and fingerprints, that cannot be seen or clearly seen by the naked eye can be photographed by using ultraviolet photographic technology. At present, in order to solve the problem of blind shooting, the existing ultraviolet photographic equipment is provided with a photomultiplier tube through photoelectric image enhancement technology, and a switching device for observation and shooting operation is also installed. The ultraviolet fluorescent reflection image of the fingerprint is finally imaged on the photomultiplier tube through the ultraviolet lens, and the fingerprint fluorescence can be observed by the naked eye after high-magnification image signal amplification processing. The observation and shooting operation windows can be switched at any time through the switching device. However, the ultraviolet photographic equipment with this structure mainly has the following technical problems:
[0004] (1) The sensitivity of the photomultiplier tube will decrease significantly when it is irradiated for a long time, thereby affecting the imaging quality.
[0005] (2) Even the ordinary photomultiplier tube has a relatively large size and weight, and its use space is limited, which increases the size and weight of the ultraviolet photographic equipment.
[0006] (3) The service life of the photomultiplier tube is reduced due to the limitation and influence of the use environment, and the price of the high-strength photomultiplier tube is higher than that of the ordinary type photomultiplier tube. Replacing the new photomultiplier tube also increases the cost of the ultraviolet photographic equipment. CONTENT OF THE UTILITY MODEL
[0007] Therefore, in order to solve the above technical problems of the existing ultraviolet photographic equipment, the utility model provides an ultraviolet photographic equipment for investigation.
[0008] The technical scheme adopted by the utility model to solve the technical problems is as follows:
[0009] The utility model provides a kind of ultraviolet photographing objective for investigation, comprising: first imaging lens group, second imaging lens group, third imaging lens group, fourth imaging lens group and CCD detector are sequentially arranged along optical path;The first imaging lens group includes first double-concave lens, first double-convex lens and first meniscus lens sequentially arranged along optical path;The second imaging lens group includes first convex-concave lens, second double-concave lens and second meniscus lens sequentially arranged along optical path;The third imaging lens group includes third double-concave lens, second double-convex lens and third meniscus lens sequentially arranged along optical path;The fourth imaging lens group includes fourth meniscus lens, ball lens and imaging lens sequentially arranged along optical path;The light emitted by target passes through the action of first double-concave lens, first double-convex lens, first meniscus lens, first convex-concave lens, second double-concave lens, second meniscus lens, third double-concave lens, second double-convex lens, third meniscus lens, fourth meniscus lens, ball lens, imaging lens in proper order and is imaged at the image plane of CCD detector.
[0010] As a preferred embodiment, the center thickness of the first double-concave lens is 25.5-28mm, the radius of curvature of its front surface is-215.32mm, the radius of curvature of its back surface is 223.78mm, and the refractive index is 1.4202-1.5314; the center thickness of the first double-convex lens is 32-36.5mm, the radius of curvature of its front surface is 189.96mm, the radius of curvature of its back surface is-193.67mm, and the refractive index is 1.401-1.512; the center thickness of the first meniscus lens is 65.5-74.5mm, the radius of curvature of its front surface is-172.41mm, the radius of curvature of its back surface is-318.65mm, and the refractive index is 1.414-1.526.
[0011] As a preferred embodiment, the distance between the center of the first double-concave lens and the center of the first double-convex lens is 63-75mm; the distance between the center of the first double-convex lens and the center of the first meniscus lens is 68-79mm.
[0012] As a preferred embodiment, the center thickness of the first convex-concave lens is 41-52.2mm, the radius of curvature of its front surface is 357mm, the radius of curvature of its back surface is 366.2mm, and the refractive index is 1.411-1.535; the center thickness of the second double-concave lens is 15.5-21mm, the radius of curvature of its front surface is-209.52mm, the radius of curvature of its back surface is 227.49mm, and the refractive index is 1.412-1.524; the center thickness of the second meniscus lens is 41-52mm, the radius of curvature of its front surface is-355.82mm, the radius of curvature of its back surface is-363.53mm, and the refractive index is 1.413-1.525.
[0013] As a preferred embodiment, the distance between the center of the first meniscus lens and the center of the second biconcave lens is 45-55mm; the distance between the center of the second biconcave lens and the center of the second meniscus lens is 45-55mm.
[0014] As a preferred embodiment, the center thickness of the third biconcave lens is 25-28.5mm, the radius of curvature of the front surface is -215.54mm, the radius of curvature of the back surface is 223.55mm, and the refractive index is 1.422-1.537; the center thickness of the second biconvex lens is 32-36mm, the radius of curvature of the front surface is 189.43mm, the radius of curvature of the back surface is -193.69mm, and the refractive index is 1.401-1.512; the center thickness of the third meniscus lens is 65-74mm, the radius of curvature of the front surface is -172.27mm, the radius of curvature of the back surface is -318.89mm, and the refractive index is 1.414-1.526.
[0015] As a preferred embodiment, the distance between the center of the third biconcave lens and the center of the second biconvex lens is 64-76mm; the distance between the center of the second biconvex lens and the center of the third meniscus lens is 65-75mm.
[0016] As a preferred embodiment, the center thickness of the fourth meniscus lens is 24-29mm, the radius of curvature of the front surface is -239.97mm, the radius of curvature of the back surface is -103.76mm, and the refractive index is 1.408-1.509; the refractive index of the spherical lens is 1.56-1.58; the center thickness of the imaging mirror is 18.5-20.5mm, the radius of curvature of the front surface is 351.46mm, and the radius of curvature of the back surface is 322.73mm.
[0017] As a preferred embodiment, the distance between the center of the fourth meniscus lens and the center of the spherical lens is 58-72mm; the distance between the center of the spherical lens and the center of the imaging mirror is 56-75mm.
[0018] The utility model provides a kind of ultraviolet photographic equipment for investigation, using the ultraviolet photographic objective lens for investigation of the utility model implementation, this ultraviolet photographic equipment includes: fuselage, lens installed in the front surface of fuselage, ultraviolet photographic objective lens installed in lens, exposure lamp and switch button all installed on the surface of fuselage, liquid crystal display screen installed in the rear surface of fuselage, data interface and power interface all installed in the side of fuselage, power module installed in the inside of fuselage;The power module is connected with CCD detector, liquid crystal display screen, exposure lamp, switch button, data interface and power interface respectively, the power module is powered by power supply interface, and the power module is powered by switch button to connect power supply to supply power to CCD detector, liquid crystal display screen, exposure lamp and data interface;The CCD detector is connected with liquid crystal display screen, and the image at the image plane of the CCD detector is displayed by liquid crystal display screen;The CCD detector is connected with data interface.
[0019] The utility model has the advantages that:
[0020] 1、The utility model does not use photomultiplier tube, but realizes high-quality imaging by designing a kind of ultraviolet photographic objective lens for investigation.Specifically, four imaging lens groups are designed, including first imaging lens group, second imaging lens group, third imaging lens group and fourth imaging lens group, the light emitted by target is incident to second imaging lens group after being affected by first imaging lens group, and most of stray light in light can be filtered out by first imaging lens group, which is conducive to improving subsequent imaging quality;Stray light affected light can be gathered by second imaging lens group, laying a foundation for improving subsequent imaging quality;Stray light in high-quality light gathered can be further filtered out by third imaging lens group, improving imaging quality.High-quality imaging can be realized by spherical lens in fourth imaging lens group.The use of ultraviolet photographic objective lens improves imaging quality without affecting detection sensitivity and imaging quality.
[0021] 2、Since the utility model does not use photomultiplier tube, but uses ultraviolet photographic objective lens and power module, liquid crystal display screen, fuselage, lens, exposure lamp, switch button, data interface and power interface, its size will not be too large, and since the quality of each lens in ultraviolet photographic objective lens is relatively light, the overall weight will not be increased, and since the size of ultraviolet photographic objective lens is relatively small, the overall size and weight of ultraviolet photographic equipment will not be increased.
[0022] 3、The utility model will not be restricted and influenced by use environment, the service life of each lens in the ultraviolet photographic objective lens used is relatively long, and the price of lens is relatively cheap, even if damaged, it is very convenient to replace, and the cost will not be increased.
[0023] 4. The utility model discloses add exposure lamp, can realize exposure compensation function, through the artificial adjustment exposure, and then adjust picture brightness, keep the stable imaging of key area. BRIEF DESCRIPTION OF DRAWINGS
[0024] Figure 1 The utility model provides a whole structure schematic diagram of ultraviolet photographic equipment for investigation.
[0025] Figure 2 The utility model provides a light path schematic diagram of ultraviolet photographic objective lens for investigation.
[0026] Figure 3 It is the light path schematic diagram of first imaging lens group.
[0027] Figure 4 It is the light path schematic diagram of second imaging lens group.
[0028] Figure 5 It is the light path schematic diagram of third imaging lens group.
[0029] Figure 6 It is the light path schematic diagram of fourth imaging lens group.
[0030] In the drawing, 1, first imaging lens group, 101, first double concave lens, 102, first double convex lens, 103, first concave convex lens, 2, second imaging lens group, 201, first convex concave lens, 202, second double concave lens, 203, second concave convex lens, 3, third imaging lens group, 301, third double concave lens, 302, second double convex lens, 303, third concave convex lens, 4, fourth imaging lens group, 401, fourth concave convex lens, 402, spherical lens, 403, imaging lens, 5, CCD detector, 6, body, 7, lens, 8, exposure lamp, 9, switch button, 10, data interface, 11, power interface. DETAILED DESCRIPTION
[0031] The utility model makes further detailed description in combination with the drawings.
[0032] First, the utility model provides a kind of ultraviolet photographic objective lens for investigation.
[0033] Referring to Figures 2 to 6 The utility model provides a kind of ultraviolet photographic objective lens for investigation, its light path structure mainly includes following lens components: first imaging lens group 1, second imaging lens group 2, third imaging lens group 3, fourth imaging lens group 4 and CCD detector 5;Wherein, according to the order of first imaging lens group 1, second imaging lens group 2, third imaging lens group 3, fourth imaging lens group 4, CCD detector 5, first imaging lens group 1, second imaging lens group 2, third imaging lens group 3, fourth imaging lens group 4, CCD detector 5 are sequentially arranged along imaging light path.
[0034] The following section provides a detailed introduction to the specific structure and parameters of the first imaging lens group 1, the second imaging lens group 2, the third imaging lens group 3, and the fourth imaging lens group 4.
[0035] like Figure 3 As shown, the first imaging lens group 1 is mainly composed of a first biconcave lens 101, a first biconvex lens 102, and a first concave-convex lens 103, which are arranged sequentially along the optical path. Specifically, the first biconcave lens 101 has a center thickness of 25.5-28 mm, a radius of curvature of -215.32 mm on its front surface R1, a radius of curvature of 223.78 mm on its rear surface R2, and a refractive index of 1.4202-1.5314; the first biconvex lens 102 has a center thickness of 32-36.5 mm, a radius of curvature of 189.96 mm on its front surface R3, a radius of curvature of -193.67 mm on its rear surface R4, and a refractive index of 1.401-1.512; the first concave-convex lens 103 has a center thickness of 65.5-74.5 mm, a radius of curvature of -172.41 mm on its front surface R5, a radius of curvature of -318.65 mm on its rear surface R6, and a refractive index of 1.414-1.526.
[0036] The distance between the center of the first biconcave lens 101 and the center of the first biconvex lens 102 is 63-75mm; the distance between the center of the first biconvex lens 102 and the center of the first concave-convex lens 103 is 68-79mm.
[0037] The light emitted from the target passes through the first biconcave lens 101, the first biconvex lens 102, and the first concave-convex lens 103 in sequence before entering the second imaging lens group 2. The first biconcave lens 101, the first biconvex lens 102, and the first concave-convex lens 103 can filter stray light in the light, which is beneficial to improving the subsequent imaging quality.
[0038] like Figure 4As shown, the second imaging lens group 2 is mainly composed of the first convex-concave lens 201, the second double-concave lens 202 and the second concave-convex lens 203, and the first convex-concave lens 201, the second double-concave lens 202 and the second concave-convex lens 203 are sequentially arranged along the optical path. Specifically, the central thickness of the first convex-concave lens 201 is 41-52.2 mm, the radius of curvature of the front surface R7 is 357 mm, the radius of curvature of the rear surface R8 is 366.2 mm, and the refractive index is 1.411-1.535; the central thickness of the second double-concave lens 202 is 15.5-21 mm, the radius of curvature of the front surface R9 is -209.52 mm, the radius of curvature of the rear surface R10 is 227.49 mm, and the refractive index is 1.412-1.524; the central thickness of the second concave-convex lens 203 is 41-52 mm, the radius of curvature of the front surface R11 is -355.82 mm, the radius of curvature of the rear surface R12 is -363.53 mm, and the refractive index is 1.413-1.525.
[0039] Wherein, the distance between the center of the first convex-concave lens 201 and the center of the second double-concave lens 202 is 45-55 mm; the distance between the center of the second double-concave lens 202 and the center of the second concave-convex lens 203 is 45-55 mm.
[0040] The light emitted by the first imaging lens group 1 sequentially passes through the first convex-concave lens 201, the second double-concave lens 202 and the second concave-convex lens 203, and then is incident on the third imaging lens group 3. The first convex-concave lens 201, the second double-concave lens 202 and the second concave-convex lens 203 can make the light affected by stray light filtering out gathered, laying a foundation for improving the subsequent imaging quality.
[0041] As shown in the figure, Figure 5 The third imaging lens group 3 is mainly composed of the third double-concave lens 301, the second double-convex lens 302 and the third concave-convex lens 303, and the third double-concave lens 301, the second double-convex lens 302 and the third concave-convex lens 303 are sequentially arranged along the optical path. Specifically, the central thickness of the third double-concave lens 301 is 25-28.5 mm, the radius of curvature of the front surface R13 is -215.54 mm, the radius of curvature of the rear surface R14 is 223.55 mm, and the refractive index is 1.422-1.537; the central thickness of the second double-convex lens 302 is 32-36 mm, the radius of curvature of the front surface R15 is 189.43 mm, the radius of curvature of the rear surface R16 is -193.69 mm, and the refractive index is 1.401-1.512; the central thickness of the third concave-convex lens 303 is 65-74 mm, the radius of curvature of the front surface R17 is -172.27 mm, the radius of curvature of the rear surface R18 is -318.89 mm, and the refractive index is 1.414-1.526.
[0042] The interval between the center of the third double-concave lens 301 and the center of the second double-convex lens 302 is 64-76mm; and the interval between the center of the second double-convex lens 302 and the center of the third double-convex lens 303 is 65-75mm.
[0043] The light rays emitted by the second imaging lens group 2 pass through the third double-concave lens 301, the second double-convex lens 302 and the third double-convex lens 303 in sequence and then are incident on the fourth imaging lens group 4.
[0044] As shown in Figure 6 The fourth imaging lens group 4 mainly comprises a fourth double-convex lens 401, a ball lens 402 and an imaging lens 403, and the fourth double-convex lens 401, the ball lens 402 and the imaging lens 403 are sequentially arranged along the optical path.
[0045] The interval between the center of the fourth double-convex lens 401 and the center of the ball lens 402 is 58-72mm; and the interval between the center of the ball lens 402 and the center of the imaging lens 403 is 56-75mm.
[0046] The light rays emitted by the third imaging lens group 3 pass through the fourth double-convex lens 401, the ball lens 402 and the imaging lens 403 in sequence and then are imaged on the image plane of the CCD detector 5.
[0047] The working principle of the ultraviolet photographic objective for investigation is as follows:
[0048] The incident light passes through the first imaging lens group 1, the second imaging lens group 2, the third imaging lens group 3 and the fourth imaging lens group 4 in sequence and then is imaged on the image plane of the CCD detector 5.
[0049] The ultraviolet photographing objective lens for investigation has a focal length of 45-65mm, a relative aperture of 4.2-4.8mm, a resolution of 2048*2048, and pixel points of 5.9-6.3μm.
[0050] In the second aspect, the utility model provides an ultraviolet photographing equipment for investigation mainly using the ultraviolet photographing objective lens for investigation of the utility model first aspect.
[0051] As Figure 1 The utility model provides an ultraviolet photographing equipment for investigation, and it specifically includes the following components:
[0052] The ultraviolet photographing objective lens, the power module, the liquid crystal display screen, the body 6, the lens 7, the exposure lamp 8, the switch button 9, the data interface 10 and the power interface 11.
[0053] Specifically, the lens 7 is installed on the front surface of the body 6, the exposure lamp 8 and the switch button 9 are both installed on the upper surface of the body 6, and the data interface 10 and the power interface 11 are both installed on the side surface of the body 6.
[0054] Meanwhile, the liquid crystal display screen is installed on the rear surface of the body 6.
[0055] In the utility model, the ultraviolet photographing objective lens is installed in the lens 7.
[0056] The CCD detector 5 in the ultraviolet photographing objective lens is connected with the power module, and after the switch button 9 is connected with the power supply, the power module can supply power to the CCD detector 5.
[0057] The CCD detector 5 in the ultraviolet photographing objective lens is connected with the liquid crystal display screen, and the image at the image plane of the CCD detector 5 is displayed through the liquid crystal display screen.
[0058] The CCD detector 5 in the ultraviolet photographing objective lens is connected with the data interface 10, and through the data interface 10, image processing and storage equipment can be externally connected, so that the image data can be received, stored and processed.
[0059] The specific working principle of the ultraviolet photographing equipment for investigation provided by the utility model is as follows:
[0060] The light emitted by the target is imaged on the image plane of the CCD detector 5 in turn through the action of the first double-concave lens 101, the first double-convex lens 102, the first meniscus lens 103, the first convex-concave lens 201, the second double-concave lens 202, the second meniscus lens 203, the third double-concave lens 301, the second double-convex lens 302, the third meniscus lens 303, the fourth meniscus lens 401, the spherical lens 402 and the imaging lens 403, and finally displayed through the liquid crystal display screen.
[0061] In the description of the present application, it should be understood that the orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be understood as a limitation on the protection scope of the present application.
[0062] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. An ultraviolet photographic device for reconnaissance, characterized in that, The application discloses a kind of ultraviolet photographic objective lens for investigation, the ultraviolet photographic objective lens includes: first imaging lens group (1), second imaging lens group (2), third imaging lens group (3), fourth imaging lens group (4) and CCD detector (5) sequentially arranged along optical path;The first imaging lens group (1) includes first double-concave lens (101), first double-convex lens (102) and first meniscus lens (103) sequentially arranged along optical path;The second imaging lens group (2) includes first convex-concave lens (201), second double-concave lens (202) and second meniscus lens (203) sequentially arranged along optical path;The third imaging lens group (3) includes third double-concave lens (301), second double-convex lens (302) and third meniscus lens (303) sequentially arranged along optical path;The fourth imaging lens group (4) includes fourth meniscus lens (401), spherical lens (402) and imaging lens (403) sequentially arranged along optical path;Light emitted by target passes through first double-concave lens (101), first double-convex lens (102), first meniscus lens (103), first convex-concave lens (201), second double-concave lens (202), second meniscus lens (203), third double-concave lens (301), second double-convex lens (302), third meniscus lens (303), fourth meniscus lens (401), spherical lens (402) and imaging lens (403) in sequence and is imaged on the image plane of CCD detector (5).
2. The ultraviolet photographic equipment for investigation according to claim 1, wherein The center thickness of the first double-concave lens (101) is 25.5-28mm, the curvature radius of the front surface thereof is-215.32mm, the curvature radius of the back surface thereof is 223.78mm, and the refractive index thereof is 1.4202-1.5314;The center thickness of the first double-convex lens (102) is 32-36.5mm, the curvature radius of the front surface thereof is 189.96mm, the curvature radius of the back surface thereof is-193.67mm, and the refractive index thereof is 1.401-1.512;The center thickness of the first meniscus lens (103) is 65.5-74.5mm, the curvature radius of the front surface thereof is-172.41mm, the curvature radius of the back surface thereof is-318.65mm, and the refractive index thereof is 1.414-1.
526.
3. The ultraviolet photographic equipment for investigation according to claim 1, wherein The spacing between the center of the first double-concave lens (101) and the center of the first double-convex lens (102) is 63-75mm;The spacing between the center of the first double-convex lens (102) and the center of the first meniscus lens (103) is 68-79mm.
4. The ultraviolet photographic equipment for investigation according to claim 1, wherein The center thickness of the first convex-concave lens (201) is 41-52.2mm, the radius of curvature of the front surface is 357mm, the radius of curvature of the back surface is 366.2mm, and the refractive index is 1.411-1.535; the center thickness of the second double-concave lens (202) is 15.5-21mm, the radius of curvature of the front surface is -209.52mm, the radius of curvature of the back surface is 227.49mm, and the refractive index is 1.412-1.524; the center thickness of the second concave-convex lens (203) is 41-52mm, the radius of curvature of the front surface is -355.82mm, the radius of curvature of the back surface is -363.53mm, and the refractive index is 1.413-1.
525.
5. The ultraviolet photographic equipment for investigation according to claim 1, wherein The distance between the center of the first convex-concave lens (201) and the center of the second double-concave lens (202) is 45-55mm; the distance between the center of the second double-concave lens (202) and the center of the second concave-convex lens (203) is 45-55mm.
6. The ultraviolet photographic equipment for investigation according to claim 1, wherein The center thickness of the third double-concave lens (301) is 25-28.5mm, the radius of curvature of the front surface is -215.54mm, the radius of curvature of the back surface is 223.55mm, and the refractive index is 1.422-1.537; the center thickness of the second double-convex lens (302) is 32-36mm, the radius of curvature of the front surface is 189.43mm, the radius of curvature of the back surface is -193.69mm, and the refractive index is 1.401-1.512; the center thickness of the third concave-convex lens (303) is 65-74mm, the radius of curvature of the front surface is -172.27mm, the radius of curvature of the back surface is -318.89mm, and the refractive index is 1.414-1.
526.
7. The ultraviolet photographic equipment for investigation according to claim 1, wherein The distance between the center of the third double-concave lens (301) and the center of the second double-convex lens (302) is 64-76mm; the distance between the center of the second double-convex lens (302) and the center of the third concave-convex lens (303) is 65-75mm.
8. The ultraviolet photographic equipment for investigation according to claim 1, wherein The center thickness of the fourth concave-convex lens (401) is 24-29mm, the radius of curvature of the front surface is -239.97mm, the radius of curvature of the back surface is -103.76mm, and the refractive index is 1.408-1.509; the refractive index of the spherical lens (402) is 1.56-1.58; the center thickness of the imaging lens (403) is 18.5-20.5mm, the radius of curvature of the front surface is 351.46mm, and the radius of curvature of the back surface is 322.73mm.
9. The ultraviolet photographic equipment for investigation according to claim 1, wherein The distance between the center of the fourth concave-convex lens (401) and the center of the spherical lens (402) is 58-72mm; the distance between the center of the spherical lens (402) and the center of the imaging lens (403) is 56-75mm.
10. The ultraviolet photographic equipment for investigation according to claim 1, wherein Also comprising: The camera body (6), the lens (7) installed on the front surface of the camera body (6), the ultraviolet camera objective installed in the lens (7), the exposure lamp (8) and the switch button (9) installed on the upper surface of the camera body (6), the liquid crystal display screen installed on the rear surface of the camera body (6), the data interface (10) and the power interface (11) installed on the side surface of the camera body (6), the power module installed in the camera body (6); the power module is connected with the CCD detector (5), the liquid crystal display screen, the exposure lamp (8), the switch button (9), the data interface (10) and the power interface (11) respectively, the power module is connected with the power supply through the power interface (11), the power module supplies power for the CCD detector (5), the liquid crystal display screen, the exposure lamp (8) and the data interface (10) by connecting the power supply through the switch button (9); the CCD detector (5) is connected with the liquid crystal display screen, the image at the image plane of the CCD detector (5) is displayed through the liquid crystal display screen; the CCD detector (5) is connected with the data interface (10).