An image acquisition device in a high radiation environment

Abstract

The present invention discloses an image acquisition device in a high radiation environment, comprising a housing, a lens assembly arranged in the housing, a light-guide camera assembly and a control module, wherein the light-guide camera assembly comprises, from the inside to the outside, a light guide tube, a sleeve, a first copper foil layer, a focusing coil, a second copper foil layer, a first deflection coil, a third copper foil layer, a second deflection coil and a shielding film layer; the lens assembly comprises a lens barrel and a lens arranged in the lens barrel; the control module comprises a power module, a data acquisition module and a data processing and transmission module, one end of the light guide tube is electrically connected to the power module, the other end of the light guide tube is provided with a target surface, and the data acquisition module is connected to the target surface and the data processing and transmission module. The image acquisition device in a high radiation environment of the present invention is an image acquisition device suitable for use in a high radiation environment (environmental dose rate up to 1 KGy / h) and is quick and convenient to install.

Description

Technical Field

[0001] The present invention belongs to the field of image acquisition technology, and in particular relates to a dynamic image acquisition device used in high radiation environments such as reactor pools in nuclear power plants, spent fuel assembly inspections, radioactive waste storage areas, and other high-radiation laboratories. Background Art

[0002] At present, the radiation-resistant cameras used in nuclear power plants are mainly ordinary radiation-resistant CCD / CMOS high-definition cameras. The optical distance is increased by optical path conversion, and the protection capability is increased by peripheral physical shielding, so as to enhance the radiation resistance of CCM / CMOS cameras. However, the enhanced radiation resistance is extremely limited, generally reaching the KGy level. In a high radiation environment (environmental dose rate up to 1KGy / h), ordinary CCD / CMOS is irradiated by high-energy rays, and the high-energy rays bombard the isolation layer SiO2 of the gate in the CMOS / CCD. 2 , which will cause electron detachment or Si-O bond breaking, the isolation layer to be turned on, imaging failure, and a sharp drop in imaging quality. In addition, due to the optical path conversion and physical shielding, the camera is large in size and heavy in weight, which cannot meet the video acquisition needs in a limited space in a high radiation environment.

[0003] Photoconductive camera tubes have strong radiation resistance, high reliability and long service life. However, existing photoconductive camera tubes used in high radiation environments of nuclear power still have problems such as insufficient compactness of structure and inconvenient and inconvenient assembly and installation. Summary of the invention

[0004] In view of this, in order to overcome the defects of the prior art, the purpose of the present invention is to provide an image acquisition device for high radiation environments. Based on the optical waveguide imaging principle of magnetic focusing and magnetic deflection, an image acquisition device suitable for high radiation environments and quick and easy to install is obtained.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An image acquisition device for a high radiation environment includes a housing, a lens assembly arranged in the housing, a light guide camera assembly and a control module, wherein the light guide camera assembly includes a light pipe, a sleeve, a first copper foil layer, a focusing coil, a second copper foil layer, a first deflection coil, a third copper foil layer, a second deflection coil and a shielding film layer in order from the inside to the outside; the lens assembly includes a lens barrel and a lens arranged in the lens barrel; the control module includes a power module, a data acquisition module and a data processing and transmission module, one end of the light pipe is electrically connected to the power module, the other end of the light pipe is provided with a target surface, and the data acquisition module is connected to the target surface and the data processing and transmission module. The lens assembly and the control module are respectively arranged at both ends of the light guide camera assembly.

[0007] According to some preferred implementation aspects of the present invention, the sleeve includes a barrel portion and a first end portion and a second end portion respectively located at both ends of the barrel portion, the first end portion includes a first elastic sheet, a connecting ring and a connecting sheet in sequence, the barrel portion is provided with a second elastic sheet, the first elastic sheet and the second elastic sheet are both extended and inclined from the sleeve toward the light guide tube, and the first elastic sheet and the second elastic sheet are used to fix the sleeve on the outer periphery of the light guide tube. The first elastic sheet and the connecting sheet on the first end portion are both connected to both sides of the connecting ring, and a plurality of first elastic sheets and a plurality of connecting sheets are evenly spaced and distributed on both sides of the connecting ring.

[0008] According to some preferred implementation aspects of the present invention, the first elastic sheet extends from the connecting ring to the end of the light guide tube and is inclined from the connecting ring to the light guide tube; the second elastic sheet extends and is inclined from the barrel to the other end of the light guide tube.

[0009] According to some preferred implementation aspects of the present invention, the first end is detachably connected to the barrel; the connecting piece has a connecting block, and the inner wall of the barrel has a corresponding connecting groove, and the connecting block is accommodated in the connecting groove for connecting the barrel and the first end. The connecting groove in the present invention is not a continuous annular groove, and there is a barrier between each connecting groove to prevent relative rotation between the first end and the barrel, thereby ensuring the synchronization of movement between the first end and the barrel.

[0010] That is, the first end portion is detachably connected to the barrel portion through a connecting block and a connecting groove, and the connecting block is arranged in an arc shape to facilitate insertion into the connecting groove; the second end portion is fixedly connected to the barrel portion. The receiving groove formed between the second end portion and the connecting ring of the first end portion can be used to accommodate and limit the first copper foil layer, the focusing coil and the second copper foil layer to prevent them from moving. When the sleeve and the light guide tube are installed, firstly, the end of the light guide tube close to the lens assembly is inserted from the end of the barrel portion close to the first end portion. After the second spring piece and the end of the light guide tube are engaged with the buckle, the first end portion of the sleeve is inserted from the other end of the light guide tube, and the connecting piece of the first end portion is close to the barrel portion and moves inward until the connecting block on the connecting piece is accommodated in the connecting groove, completing the installation of the sleeve and the fixing between the sleeve and the light guide tube. And through the setting of the above-mentioned sleeve, the light guide tube and the sleeve are fixed and it can be ensured that the light guide tube will not be damaged during the fixing process.

[0011] According to some preferred embodiments of the present invention, a support tube is provided between the second copper foil layer and the first deflection coil; the end of the support tube has an insert block extending outwardly from the support tube in parallel, the connecting ring has a slot, the insert block is received in the slot, and is used to drive the sleeve and the light guide to rotate when the support tube rotates. The support tube is sleeved outside the second copper foil layer, and has a groove on its outer wall for accommodating the first deflection coil, the third copper foil layer, and the second deflection coil, and has a limit block for fixing the first deflection coil and the second deflection coil.

[0012] According to some preferred embodiments of the present invention, the outer wall of the support tube has a limiting portion that is perpendicular to the support tube wall and extends outward, a limiting groove is formed between two limiting portions, and the first deflection coil, the third copper foil layer and the second deflection coil are accommodated in the limiting groove.

[0013] According to some preferred implementation aspects of the present invention, a groove is defined in the limiting slot, and the first deflection coil is accommodated in the groove.

[0014] According to some preferred embodiments of the present invention, the first deflection coil is a horizontal deflection coil; the second deflection coil is a vertical deflection coil. The focusing coil in the present invention is designed inside, and its main function is to focus the electron beam. The focusing coil can also be designed outside the deflection coil, but this will greatly increase the volume of the deflection coil, because in order to obtain the same central magnetic field, the larger the radius, the more coil turns are required under the same coil current. Placing the focusing coil inside can greatly reduce the volume of the coil. Although the volume of the deflection coil will increase, since the number of turns of the deflection coil is much less than that of the focusing coil, the increase in the number of turns of the deflection coil is acceptable, which is more advantageous than designing the focusing coil outside.

[0015] According to some preferred implementation aspects of the present invention, a fixing frame is provided in the housing, the fixing frame is sleeved on the outer periphery of the end of the light guide tube close to the control module, the inner wall of the housing protrudes inward to form a convex ring, and the fixing frame is accommodated in the convex ring. The fixing frame is connected to the housing and is used to fix the end of the light guide tube away from the lens assembly and the support tube.

[0016] According to some preferred implementation aspects of the present invention, a threaded ring is fixed on the fixing frame, and an internal thread is provided on the inner wall of the threaded ring. An external thread is provided on the end of the support tube close to the fixing frame, and the internal thread cooperates with the external thread to connect the support tube and the threaded ring and adjust the insertion depth of the light guide. That is, the support tube and the fixing frame are fixedly connected by the threaded ring, and the screw-in depth of the support tube can be controlled by the threaded connection. Since the plug block of the support tube is embedded in the slot of the connecting ring, the support tube rotates, driving the sleeve and the light guide to rotate, and then the insertion depth of the light guide can be adjusted.

[0017] According to some preferred implementation aspects of the present invention, the inner diameter of the threaded ring is greater than the outer diameter of the connecting ring.

[0018] According to some preferred embodiments of the present invention, the threaded ring outer shell is provided with a wiring fixing ring, and the wiring fixing ring is provided with a wire groove for fixing the wires, and the wires are used to electrically connect the coil, the copper foil layer, the shielding layer and the power module.

[0019] According to some preferred implementation aspects of the present invention, a shielding tube is provided between the optical camera assembly and the lens barrel assembly, and the shielding tube is connected to one end of the support tube away from the threaded ring, that is, one end of the support tube is connected to the shielding tube, and the other end is connected to the threaded ring.

[0020] According to some preferred implementation aspects of the present invention, a socket is fixed on the fixing frame, the socket is plugged into the end of the light guide, and the power module is electrically connected to the socket. Through the connection between the socket and the power module, one end of the light guide is controlled to emit electrons to the other end.

[0021] According to some preferred implementation aspects of the present invention, a support rod is provided in the housing, the control module is fixed on the support rod, and both ends of the support rod are fixed on the lens barrel and the housing respectively. The power module, data acquisition module and data processing and transmission module in the control module are fixed by the support rod, and the structural strength of the whole device can be enhanced.

[0022] Due to the adoption of the above technical scheme, compared with the prior art, the advantages of the present invention are: the image acquisition device for high radiation environment of the present invention is based on the optical waveguide camera principle of magnetic focusing and magnetic deflection, and through the overall structural design of the image acquisition device and the structural design of the optical waveguide camera component, an image acquisition device suitable for high radiation environment (environmental dose rate up to 1KGy / h) and quick and easy to install is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a stereoscopic diagram of an image acquisition device in a high radiation environment in a preferred embodiment of the present invention;

[0025] Figure 2 This is a stereoscopic diagram of the image acquisition device in a high radiation environment in a preferred embodiment of the present invention after the housing is hidden;

[0026] Figure 3 It is a cross-sectional view of an image acquisition device in a high radiation environment in a preferred embodiment of the present invention;

[0027] Figure 4 It is a cross-sectional view of a light-conducting camera assembly in an image acquisition device in a high-radiation environment in a preferred embodiment of the present invention;

[0028] Figure 5 It is a partial exploded view of a light-conducting camera assembly in an image acquisition device in a high-radiation environment in a preferred embodiment of the present invention;

[0029] Figure 6 A three-dimensional diagram of a sleeve in an image acquisition device in a high radiation environment in a preferred embodiment of the present invention;

[0030] Figure 7 A stereoscopic diagram of another viewing angle of the sleeve in the image acquisition device in a high radiation environment in a preferred embodiment of the present invention;

[0031] Figure 8 It is a cross-sectional view of a sleeve in an image acquisition device in a high radiation environment in a preferred embodiment of the present invention;

[0032] Fig. 9 It is a three-dimensional diagram of a support tube in an image acquisition device in a high radiation environment in a preferred embodiment of the present invention;

[0033] Fig.10 A three-dimensional diagram of a deflection coil in an image acquisition device in a high radiation environment in a preferred embodiment of the present invention;

[0034] Fig.11 A schematic diagram of the working principle of the light guide in a preferred embodiment of the present invention;

[0035] Fig.12 It is a schematic diagram of a circuit design framework corresponding to an image acquisition device in a high radiation environment in a preferred embodiment of the present invention;

[0036] Fig.13 A schematic diagram of a high-voltage boost circuit corresponding to an image acquisition device in a preferred embodiment of the present invention;

[0037] Fig.14 A schematic diagram of a filter circuit corresponding to an image acquisition device in a preferred embodiment of the present invention;

[0038] Fig.15 This is a photographic effect diagram of an image acquisition device in a high radiation environment in a preferred embodiment of the present invention;

[0039] In the accompanying drawings, image acquisition device 1, housing 2, convex ring 21, support rod 22, cable 3, optical camera assembly 4, optical tube 41, sleeve 42, first end 421, first spring piece 4211, connecting ring 4212, slot 4213, connecting piece 4214, connecting block 4215, second end 422, barrel 423, second spring piece 4231, connecting groove 4232, first copper foil layer 43, focusing coil 44, The second copper foil layer -45, the supporting tube -46, the limiting part -461, the groove -462, the limiting block -463, the insert block -464, the first deflection coil -47, the third copper foil layer -48, the second deflection coil -49, the shielding film layer -410, the lens barrel -51, the lens -52, the power module -61, the data acquisition module -62, the data processing and transmission module -63, the fixing frame -7, the socket -8, the threaded ring -9, the wire trough -10, the wiring fixing ring -11, the shielding tube -12. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0041] like Fig.11 As shown, the working principle of the light guide in this embodiment is first introduced. Fig.11 In the figure, G1 is the heating pole: the heating source of the hot cathode, with a heating wire inside, which can generate hundreds or even thousands of degrees of temperature when working, thereby heating the cathode and making it easy to emit electrons; G2 is the cathode: the cathode is a barrel-shaped metal coated with metal oxide on the surface, which can emit electrons under heating conditions; G3 is the control pole: controls the density of the emitted electron beam; G4 is the acceleration pole: a positive electric field is formed between the control pole and the acceleration pole, which can accelerate electrons; G5 is the focusing stage: an electric field is formed between the G5 pole and the G6 pole field net, and at the same time, combined with the focusing magnetic field generated by the focusing coil, field, which can produce a more ideal focusing field; G6 is the field network: a deceleration electric field can be formed near the field network, thereby decelerating the electrons and making most of the electrons go vertically to the target; G7 is the target surface: the target surface includes a transparent conductive film and a photoconductive film. The imaging light passes through the transparent conductive film and is incident on one side of the photoconductive film, where the electrons are excited to the conduction band to form hole-electron pairs, and then the electrons on the scanning surface are attracted. The stronger the light, the higher the potential on the scanning surface. When the electron beam scans the pixel point, it generates electricity for it, so that the corresponding signal is detected at the signal electrode connected to the G7 target surface.

[0042] The working mode of the photoconductive camera assembly in this embodiment is magnetic deflection and magnetic focusing. The focusing and deflection of the electron beam are completed by the magnetic field. By controlling the current in the focusing coil, the electron beam can be formed into an extremely fine point on the target surface. By controlling the current of the deflection coil, the electron beam can be scanned left and right and up and down. The image signal is converted into current through the scanning of the electron beam, and then collected by the collection current, and finally restored to an image and transmitted through the network port. The generation of the electron beam requires high voltage, and high voltage is required to generate different voltages.

[0043] Example 1 Specific structure of the image acquisition device in a high radiation environment

[0044] like Figure 1-Figure 10 As shown, the image acquisition device 1 in a high radiation environment in this embodiment includes a housing 2, a lens assembly arranged in the housing 2, a light guide camera assembly 4, a control module, and a cable 3 connected to the control module. The lens assembly and the control module are respectively arranged at the two ends of the light guide camera assembly 4. The lens assembly includes a lens barrel 51 and a lens 52 arranged in the lens barrel 51; the control module includes a power module 61, a data acquisition module 62, and a data processing and transmission module 63. A support rod 22 is arranged in the housing 2, and the control module is fixed on the support rod 22. The two ends of the support rod 22 are respectively fixed on the lens barrel 51 and the housing 2. The power module 61, the data acquisition module 62, and the data processing and transmission module 63 in the control module are fixed by the support rod 22, and the overall structural strength of the device can be enhanced.

[0045] The optical camera assembly 4 includes, from the inside to the outside, an optical guide tube 41, a sleeve 42, a first copper foil layer 43, a focusing coil 44, a second copper foil layer 45, a support tube 46, a first deflection coil 47, a third copper foil layer 48, a second deflection coil 49, and a shielding film layer 410. A fixing frame 7 is provided in the housing 2, and the fixing frame 7 is sleeved on the end of the optical guide tube 41. The inner wall of the housing 2 protrudes inward to form a convex ring 21, and the fixing frame 7 is accommodated in the convex ring 21. The fixing frame 7 is connected to the housing 2 and is used to fix the end of the optical guide tube 41 away from the lens assembly and the support tube 46. A socket 8 is fixed on the fixing frame 7, and the socket 8 is plugged into the end of the optical guide tube 41, and the power module 61 is electrically connected to the socket 8. The socket 8 is connected to the power module 61 to control one end of the optical guide tube 41 to emit electrons to the other end. The power module 61 is used to provide the high voltage required for electron beam generation, and is electrically connected to the coils (focusing coil 44 and deflection coil), and is electrically connected to the copper foil and the shielding film layer 410 to provide zero potential.

[0046] One end of the light guide 41 is electrically connected to the power module 61, and the other end of the light guide 41 is provided with a target surface. The data acquisition module 62 is connected to the target surface and the data processing and transmission module 63 for collecting and transmitting signals. Based on the principle of optical imaging with magnetic focusing and magnetic deflection, through the overall structural design of the image acquisition device 1 and the structural design of the optical imaging component 4, an image acquisition device 1 suitable for high radiation (environmental dose rate up to 1 KGy / h) environment and quick and easy to install is obtained.

[0047] The following is a detailed description of some important components:

[0048] 1) Sleeve 42

[0049] like Figure 5-8 As shown, the sleeve 42 includes a barrel 423 and a first end 421 and a second end 422 located at both ends of the barrel 423. The first end 421 includes a first elastic piece 4211, a connecting ring 4212 and a connecting piece 4214 in sequence. The barrel 423 is provided with a second elastic piece 4231. The first elastic piece 4211 and the second elastic piece 4231 are both extended and inclined from the sleeve 42 to the light guide 41. The first elastic piece 4211 and the connecting piece 4214 on the first end 421 are both connected to both sides of the connecting ring 4212, and a plurality of first elastic pieces 4211 and a plurality of connecting pieces 4214 are evenly spaced and distributed on both sides of the connecting ring 4212. The barrel 423 and the first end 421 are detachably connected; the connecting piece 4214 is provided with a connecting block 4215, and a connecting groove 4232 is correspondingly provided on the inner wall of the barrel 423. The connecting block 4215 is accommodated in the connecting groove 4232 for connecting the barrel 423 and the first end 421. In addition, the connecting groove 4232 in this embodiment is not a continuous annular groove, and there is a barrier between each connecting groove 4232 to prevent relative rotation between the first end 421 and the barrel 423, thereby ensuring the synchronization of the movement between the first end 421 and the barrel 423.

[0050] The first elastic piece 4211 extends from the connecting ring 4212 to the end of the light pipe 41 and is inclined from the connecting ring 4212 to the light pipe 41; the second elastic piece 4231 extends from the cylinder 423 to the other end of the light pipe 41 and is inclined. That is, the diameter of the circle formed by the plurality of first elastic pieces 4211 and the plurality of second elastic pieces 4231 is smaller than the outer diameter of the light pipe.

[0051] The first end 421 and the barrel 423 are detachably connected through the connecting block 4215 and the connecting groove 4232, and the connecting block 4215 is arranged in an arc shape to facilitate insertion into the connecting groove 4232; the second end 422 and the barrel 423 are fixedly connected. The receiving groove formed between the second end 422 and the connecting ring 4212 of the first end 421 can be used to receive and limit the first copper foil layer 43, the focusing coil 44 and the second copper foil layer 45 to prevent them from moving.

[0052] When installing the sleeve 42 and the light guide 41, first insert the end of the light guide 41 close to the lens assembly, that is, the target surface side, from the end of the barrel 423 close to the first end 421, and after the second spring piece 4231 and the end of the light guide 41 are engaged and buckled, the first end 421 of the sleeve 42 is inserted from the other end of the light guide 41, and the connecting piece 4214 of the first end 421 is close to the barrel 423 and moves inward until the connecting block 4215 on the connecting piece 4214 is accommodated in the connecting groove 4232, completing the installation of the sleeve 42 and the fixing between the sleeve 42 and the light guide 41. And through the above-mentioned setting of the sleeve 42, the light guide 41 and the sleeve 42 are fixed, which can ensure that the light guide 41 will not be damaged during the fixing process, and effectively ensure the consistency of the rotation of the sleeve 42 and the light guide 41.

[0053] 2) Support tube 46

[0054] like Figure 5 and 9 As shown, the end of the support tube 46 has an insert block 464 extending outwardly from the support tube 46 in parallel, and a slot 4213 is provided on the connecting ring 4212. The insert block 464 is accommodated in the slot 4213, and is used to drive the sleeve 42 and the light guide 41 to rotate while the support tube 46 rotates. The support tube 46 is sleeved outside the second copper foil layer 45, and has a groove on its outer wall for accommodating the first deflection coil 47, the third copper foil layer 48 and the second deflection coil 49, and has a limit block 463 for fixing the first deflection coil 47 and the second deflection coil 49. The first deflection coil 47 is a horizontal deflection coil; the second deflection coil 49 is a vertical deflection coil.

[0055] At the same time, the outer wall of the support tube 46 has a limiting portion 461 that is perpendicular to the wall of the support tube 46 and extends outward, and a limiting groove is formed between the two limiting portions 461, and the first deflection coil 47, the third copper foil layer 48 and the second deflection coil 49 are accommodated in the limiting groove. Preferably, a groove 462 is opened in the limiting groove, and the first deflection coil 47 is accommodated in the groove 462.

[0056] The focusing coil 44 in this embodiment is designed to be inside, and its main function is to focus the electron beam. The focusing coil 44 can also be designed to be outside the deflection coil, but this will greatly increase the volume of the deflection coil, because in order to obtain the same central magnetic field, the larger the radius, the more coil turns are required under the same coil current. Placing the focusing coil 44 inside can greatly reduce the volume of the coil. Although the volume of the deflection coil will increase, since the number of turns of the deflection coil is much less than that of the focusing coil 44, the increase in the number of turns of the deflection coil is acceptable, which is more advantageous than designing the focusing coil 44 outside.

[0057] 3) Threaded ring 9

[0058] like Figure 2-4 As shown, the threaded ring 9 is fixedly connected to the fixing frame 7, and the inner diameter of the threaded ring 9 is larger than the outer diameter of the connecting ring 4212. An internal thread is provided on the inner wall of the threaded ring 9, and an external thread is provided on the end of the support tube 46 close to the fixing frame 7, and the internal thread and the external thread cooperate to fix the support tube 46 and adjust the insertion depth of the light guide 41. That is, the support tube 46 and the fixing frame 7 are fixedly connected through the threaded ring 9, and the screw-in depth of the support tube 46 can be controlled through the threaded connection. In addition, since the insert block 464 of the support tube 46 cooperates with the slot 4213 of the connecting ring 4212 to be embedded and connected, the support tube 46 rotates, driving the sleeve 42 and the light guide 41 to rotate, and then the insertion depth of the light guide 41 can be adjusted.

[0059] Wires are arranged between the coil, the copper foil layer, the shielding layer and the power module 61 to achieve electrical connection. A wiring fixing ring 11 is arranged on the outer surface of the threaded ring 9, and a wire groove 10 for fixing the wires is opened on the wiring fixing ring 11; a wire groove 10 is also opened on the limiting portion 461 of the support tube 46 near the end of the fixing frame 7.

[0060] In this embodiment, a shielding tube 12 is arranged between the light guide camera assembly 4 and the lens barrel 51 assembly, and the shielding tube 12 is connected to one end of the support tube 46 away from the threaded ring 9. That is, one end of the support tube 46 is connected to the shielding tube 12, and the other end is connected to the threaded ring 9.

[0061] Example 2 Circuit design of image acquisition device in high radiation environment

[0062] like Figure 12-14 As shown, this embodiment provides a circuit structure design corresponding to the image acquisition device structure in Embodiment 1, which mainly includes a high-voltage boost circuit, a voltage stabilizing circuit, a precision amplification acquisition circuit, a filtering circuit, an ADC sampling circuit, a current control circuit, an image processing circuit, etc. The basic design framework is as follows Fig.12 shown.

[0063] The main principle is: the high-voltage circuit generates the voltage required for the normal operation of the light pipe. The high-voltage circuit uses a resonant circuit to generate a low-ripple voltage source. The hot cathode in the light pipe is heated to excite electrons, which pass through the control electrode, the acceleration electrode, and finally the deceleration electrode and are vertically incident on the target surface. When the image target surface is illuminated by light, a fluctuating electric potential is generated. After being illuminated by the back of the electron beam, a discharge process occurs and current is generated. The maximum signal current is 300nA, which passes through a precision transimpedance amplifier and is finally collected by a high-speed ADC. When the current of the horizontal and vertical deflection coils is controlled, the electron beam can be controlled to scan from left to right and from top to bottom, and finally the strong and weak signals of the image are converted into strong and weak signals of the current. The accuracy of imaging is related to the focusing ability, scanning linearity and afterglow hysteresis characteristics of the electron beam. The obtained image signal is compared with the scanning timing, and the delay compensation is added to finally obtain the completed image. The obtained image is digitally filtered, the detailed features are enhanced, and finally compressed into a video format and transmitted to the imaging end for display through the network port.

[0064] The following is a detailed description of some circuit structures:

[0065] 1) High voltage boost circuit

[0066] Using a two-switch boost forward circuit, the DSP outputs a precise ePWM wave to control the on / off of the MOS, thereby generating a changing current in the transformer, and then inducing a high potential in the secondary coil. The induced high potential generates different voltages through different voltage-dividing nodes, which provide voltages for the control pole, acceleration pole, focusing pole and deceleration pole of the light guide.

[0067] 2) Voltage stabilization circuit

[0068] The voltage stabilization circuit requires a voltage source with sufficient accuracy. The power supply of the high-speed acquisition circuit is provided by LDO, which generates less noise and has less impact on the image signal. The power supply of the high-voltage boost circuit can use BuckBoost circuit to ensure the efficiency of the power supply. In order to prevent the noise emitted by the high-frequency inductor from affecting the circuit acquisition, a shielding layer needs to be added.

[0069] 3) Amplification and acquisition circuit

[0070] The requirements for the low noise amplifier circuit in this embodiment are as follows:

[0071]

[0072]

[0073] The most important thing for the preamplifier circuit is to eliminate noise and convert and amplify the current signal into a voltage signal. The possible noise sources are as follows: resistor thermal noise, scattering noise; transistor flicker noise, burst noise; power supply noise; amplifier noise; interference noise caused by signal lines, such as parasitic capacitance, parasitic inductance, mechanical vibration noise; electromagnetic wave interference noise; noise caused by ground loop.

[0074] In order to prevent the signal current from being submerged in the noise signal, reasonable selection design, filtering, wiring layout, grounding, shell shielding, electrostatic shielding, etc. are required. Due to the high impedance characteristics of the optical tube, a low-noise JFET amplifier is selected at the front end. Because the signal rate of the optical tube is high, the input capacitance of the JFET must be small. In addition, the signal frequency is high and the noise generated is large. The LC oscillation circuit is used to improve the signal quality.

[0075] Therefore, the present embodiment adopts the following design details: add LC or RC filter to the front end, use voltage stabilizer and LDO chip for high precision, the voltage output can be as close to the amplifier as possible and away from the high-frequency signal source; signal grounding: in order to shield interference, use shielded wire, and the outer shell of the shielded wire is grounded. When the transmission signal line is very long, it is necessary to consider the influence of the grounding loop, and signal coupling can be used. A shielding cover can be added to the high-frequency transformer, with a high magnetic permeability material inside and a low magnetic permeability material outside; constant temperature, in order to make the components work within the normal range, the ambient temperature must be guaranteed to be within a certain range, especially high temperature will cause the amplifier and other components to fail, and the temperature must be constant, and the working temperature is set at about 45°C. A resistance wire and a temperature sensor can be combined. If the working temperature exceeds 45°C, it will greatly affect the imaging quality.

[0076] 4) Filter circuit

[0077] The image produced by the provided photoconductive camera tube is a grayscale image, and the signal center frequency is 3MHz. The signal frequency cannot exceed 3MHz. A frequency that is too fast will lose signal quality due to the influence of signal afterglow hysteresis. This means that the circuit image is about 25 frames per second, and no signal will be obtained if it is higher. The signal frequency is 3MHz, the signal center frequency is 3MHz, and a Bessel low-pass filter is used with a cutoff frequency of 6MHz. The structural design diagram is shown in the figure. Fig.14 shown.

[0078] 5)ADC sampling circuit

[0079] There are many types of ADCs. The image sampling frequency is 6M. The ADC sampling accuracy inside the MUC is 12bit. For 8-bit encoded grayscale images, the image resolution is sufficient, but the ADC clock frequency is at least greater than 12M (according to the double sampling theorem). An external high-speed ADC is used to read data through the high-speed parallel port and finally collected by the DSP.

[0080] 6) Current control circuit

[0081] The focusing deflector requires a constantly changing magnetic field. In order to simplify the design, a controllable current source can be used. The chip outputs a control voltage according to the TV accuracy of the image to be displayed, thereby generating a magnetic field in the refocusing deflector to control the movement of electrons. The timing can be generated by the timer inside the microcontroller. However, sometimes the frequency of electronic scanning is high, scanning an image of about 50,000 points, scanning 25 images per second, a total of 1.25 million points, and a high-speed DAC is required to generate the corresponding control voltage. In order to ensure the left, right, up and down scanning of the electron beam, a corresponding current bias circuit is required.

[0082] 7) Image processing circuit

[0083] Industrial-grade DSP chips are used to process images. The image signals obtained need to undergo a series of operations such as digital filtering, gamma adjustment, and image enhancement to obtain a clear image. Finally, the image needs to be compressed, converted into a video format, and transmitted through the network port. DSP has fast floating-point operations and is suitable for image processing. The STM32 interface is chosen because it has a built-in network port, which simplifies the design and can share part of the burden of STM32 image processing.

[0084] The image acquisition device for high-radiation environments of the present invention has a compact structure, high reliability, and quick installation: the optical camera component adopts a compact design, and its product size is small and easy to install; it has strong radiation resistance: the maximum radiation resistance dose per hour can reach up to 30,000 Gy / h, and the total radiation resistance dose can reach 200 WGy, and it can go deep into high-radiation areas that ordinary people dare not approach to monitor the operation of nuclear power plants; it has a long service life: the service life is related to the environmental radiation intensity, and the cumulative total amount can reach up to 200 WGy, and it can work continuously for 2000 hours under high-intensity radiation of 1000 Gy / h.

[0085] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An image acquisition device in a high radiation environment, characterized in that: The invention comprises a housing, a lens assembly arranged in the housing, a light-guide camera assembly and a control module, wherein the light-guide camera assembly comprises, from the inside to the outside, a light pipe, a sleeve, a first copper foil layer, a focusing coil, a second copper foil layer, a first deflection coil, a third copper foil layer, a second deflection coil and a shielding film layer; the lens assembly comprises a lens barrel and a lens arranged in the lens barrel; the control module comprises a power module, a data acquisition module and a data processing and transmission module, one end of the light pipe is electrically connected to the power module, the other end of the light pipe is provided with a target surface, and the data acquisition module is connected to the target surface and the data processing and transmission module; The sleeve comprises a barrel portion and a first end portion and a second end portion respectively located at two ends of the barrel portion, the first end portion comprises a first elastic sheet, a connecting ring and a connecting sheet in sequence, the barrel portion is provided with a second elastic sheet, the first elastic sheet and the second elastic sheet both extend and tilt from the sleeve toward the light guide tube, and the first elastic sheet and the second elastic sheet are used to fix the sleeve on the outer periphery of the light guide tube; A support tube is arranged between the second copper foil layer and the first deflection coil; an insert block is provided at the end of the support tube and extends outward from the support tube, a slot is provided on the connecting ring, the insert block is accommodated in the slot, and is used to drive the sleeve and the light guide tube to rotate while the support tube rotates; A fixing frame is arranged in the shell, and the fixing frame is sleeved on the outer periphery of the end of the light guide tube. The inner wall of the shell protrudes inward to form a convex ring, and the fixing frame is accommodated in the convex ring; a threaded ring is fixed on the fixing frame, and an internal thread is opened on the inner wall of the fixing frame. An external thread is arranged on the end of the support tube close to the fixing frame, and the internal thread cooperates with the external thread to connect the support tube and the threaded ring and adjust the insertion depth of the light guide tube.

2. The image acquisition device according to claim 1, characterized in that: The first elastic sheet extends from the connecting ring to the end of the light guide tube and is inclined from the connecting ring to the light guide tube; the second elastic sheet extends from the cylinder to the other end of the light guide tube and is inclined.

3. The image acquisition device according to claim 1, characterized in that: The first end portion is detachably connected to the barrel portion; the connecting piece is provided with a connecting block, and a connecting groove is correspondingly provided on the inner wall of the barrel portion, and the connecting block is accommodated in the connecting groove for connecting the barrel portion and the first end portion.

4. The image acquisition device according to claim 1, characterized in that: The outer wall of the support tube has a limiting portion which is perpendicular to the support tube wall and extends outwards, a limiting groove is formed between two limiting portions, and the first deflection coil, the third copper foil layer and the second deflection coil are accommodated in the limiting groove.

5. The image acquisition device according to claim 4, characterized in that: A groove is provided in the limiting groove, and the first deflection coil is accommodated in the groove.

6. The image acquisition device according to claim 1, characterized in that: The first deflection coil is a horizontal deflection coil; the second deflection coil is a vertical deflection coil.

7. The image acquisition device according to claim 1, characterized in that: The inner diameter of the threaded ring is greater than the outer diameter of the connecting ring.

8. The image acquisition device according to claim 1, characterized in that: The threaded ring outer shell is provided with a wiring fixing ring, and the wiring fixing ring is provided with a wire groove for fixing electric wires, and the electric wires are used to electrically connect the coil, the copper foil layer, the shielding layer and the power module.

9. The image acquisition device according to claim 1, characterized in that: A shielding tube is arranged between the light-guide camera assembly and the lens barrel assembly, and the shielding tube is connected to an end of the support tube away from the threaded ring.

10. The image acquisition device according to claim 1, characterized in that: A socket is fixed on the fixing frame, the socket is plugged into the end of the light guide tube, and the power module is electrically connected to the socket.

11. The image acquisition device according to claim 1, characterized in that: A support rod is arranged in the shell, the control module is fixed on the support rod, and two ends of the support rod are respectively fixed on the lens barrel and the shell.

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