A liquid level detection fixture for proton exchange

Abstract

The present invention discloses a liquid level detection fixture for proton exchange, comprising a substrate slot block, a clamping rod, a light guide rod and a transceiver module, wherein the lower part of the clamping rod is provided with a substrate slot block, the light guide rod is arranged inside the clamping rod, and the top of the light guide rod is provided with a transceiver module; the bottom end of the clamping rod is provided with a base, a bottom support plate is provided below the base, and a through hole B for permeating proton exchange liquid is provided on the bottom support plate. The present invention is simple and reliable, novel in structure, and low in cost, and is worthy of further promotion and use.

Description

Technical Field

[0001] The invention relates to the technical field of photoelectric sensors, and in particular to a liquid level detection fixture for proton exchange, which is mainly used in the proton exchange process of lithium niobate waveguide chip manufacturing and alarming the liquid level of proton exchange liquid. Background Art

[0002] The multifunctional integrated optical modulator is the core device of the closed-loop fiber gyroscope. The current mainstream multifunctional integrated optical modulator is a lithium niobate waveguide modulator based on the proton exchange annealing process. The proton exchange process is to load the lithium niobate substrate onto a quartz fixture, first preheat it to 240°C in a constant temperature box, then take the chip out of the constant temperature box and quickly put it into the proton exchange liquid for proton exchange. By replacing Li + in lithium niobate with H +, the TE mode refractive index of the exchange area is increased while the TM mode refractive index is reduced to form a single polarization propagation area. After a certain exchange time, the chip is taken out of the proton exchange liquid for annealing. However, this preheating method will cause large fluctuations in the temperature of the proton exchange liquid, and the size of each temperature fluctuation is affected by the temperature difference between the lithium niobate substrate and the exchange liquid at the beginning of the exchange, resulting in poor consistency of the prepared lithium niobate waveguide chip.

[0003] In order to improve the consistency of the prepared lithium niobate waveguide chip, before the lithium niobate substrate is immersed in the proton exchange liquid, the bottom surface of the quartz fixture can be allowed to contact the proton exchange liquid for heat conduction. The lithium niobate substrate does not contact the proton exchange liquid. After staying at the liquid surface for a few minutes, the lithium niobate substrate is immersed in the proton exchange liquid for proton exchange. This can effectively reduce the temperature fluctuation during the proton exchange process. If the above-mentioned secondary preheating of the substrate by heat conduction is to be realized, the fixture for loading the lithium niobate substrate must have a liquid level detection function.

[0004] There are many kinds of sensors currently used for liquid level measurement. Among them, the float level sensor has a simple structure, but the presence of movable parts makes it difficult to overcome the liquid surface shaking, and is not suitable for dynamic liquid level measurement; the capacitive level sensor has low cost, but is easily interfered by external factors such as temperature and electromagnetic waves, and the presence of steam above the liquid may cause the sensor to false alarm or even fail; the ultrasonic level sensor has good safety performance and can be used to measure high-viscosity and highly corrosive liquids, but there is a measurement blind spot, and the error will be large when the liquid surface shakes.

[0005] With the rapid development of fiber optic technology, fiber optic sensors are widely used in the field of liquid level measurement due to their advantages such as good electrical isolation, strong anti-electromagnetic interference, corrosion resistance, and water resistance. In terms of point-type optical fiber liquid level measurement, there are mainly the following types: Optical fiber point-type liquid level sensor based on frustrated total internal reflection. When the probe is in different media, the amount of light reflected by total internal reflection is different due to different refractive indices. By measuring the reflected light power, it can be known whether the prism is in contact with the liquid surface. The key lies in the design of the optical refraction detection element structure. The detection element has cone, semicircle and prism shapes. Optical fiber point-type liquid level sensor based on Fresnel reflection. Due to the different refractive indices of air and the measured liquid, the total amount of light refracted into the medium is different, and the amount of light reflected back is also different. By detecting the amount of reflected light received by the photoelectric detector, it can be determined whether the optical fiber is in contact with the liquid surface. Optical fiber point-type liquid level sensor based on light scattering. Its measuring end is wedge-shaped. Depending on whether there is liquid at the wedge end face, the transmission characteristics of the signals of different light intensities received by the end face are different. The differential signal of the receiving optical fiber is much greater than zero after amplification. The detector and related circuits are used to detect the size of the received light intensity to determine whether the sensing probe at the wedge end face of the optical fiber sensor is in contact with the liquid surface.

[0006] The current proton exchange process cannot achieve precise temperature control. There are many point-type liquid level sensors in the existing technology, but none of them are combined with the proton exchange fixture design. Therefore, designing a liquid level detection fixture for proton exchange is the key to solving the problem of large temperature fluctuations in proton exchange and achieving precise temperature control. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention proposes a liquid level detection fixture for proton exchange in order to solve the above deficiencies, which is mainly used for detecting the proton exchange liquid level manufactured by an integrated optical modulator for a fiber optic gyroscope.

[0008] The proton exchange liquid is a mixed melt of benzoic acid and lithium benzoate. The lithium benzoate content is relatively low, so its refractive index is similar to that of the benzoic acid melt. The liquid level information can be obtained based on the different reflectivities of light at the glass-air interface and the glass-benzoic acid melt interface.

[0009] In two different media, air and proton exchange fluid, the reflected light power in the optical fiber is different due to the different refraction between the two. Liquid level measurement can be achieved by detecting the reflected light power.

[0010] The liquid level detection fixture for proton exchange described in the present invention is realized by the following technical solutions:

[0011] Provided is a liquid level detection fixture for proton exchange, comprising a substrate slot block, a clamping rod, a light guide rod and a transceiver module, wherein the substrate slot block is provided at the lower part of the clamping rod, the light guide rod is arranged inside the clamping rod, and the transceiver module is provided on the top of the light guide rod; a base is provided at the bottom end of the clamping rod, a bottom support plate is provided below the base, a through hole B for permeating proton exchange liquid is provided on the bottom support plate, and the base is used to position the substrate slot block so that the substrate slot block can be nested on the clamping rod.

[0012] Further, the substrate slot block includes a first mounting plate, a second mounting plate and a mounting block, the mounting block is provided with a hollow mounting hole, the first mounting plate is arranged at the upper end of the mounting block, and the middle part of the first mounting plate is provided with a through hole communicating with the mounting hole, the second mounting plate is arranged at the lower end of the mounting block, and the middle part of the second mounting plate is provided with a through hole communicating with the mounting hole, the first mounting plate, the mounting block and the second mounting plate are sequentially connected to form a substrate slot block with an annular groove in the middle part, and the substrate slot block is sleeved on the lower part of the clamping rod through the mounting hole.

[0013] Grooves for loading lithium niobate substrates are provided near the edges of the lower surface of the first mounting plate and the upper surface of the second mounting plate. A plurality of through holes A are provided on both the first mounting plate and the second mounting plate, and the through holes A are used to reduce the buoyancy of the proton exchange liquid on the fixture when the fixture is immersed.

[0014] Furthermore, a cavity with openings at both ends is provided in the clamping rod, and the cavity includes a cylindrical hollow column cavity and a crescent-shaped hollow column cavity. The design of the crescent-shaped hollow column cavity can reduce the weight of the clamping rod and save materials;

[0015] The light guide rod is arranged in the cavity of the cylindrical hollow column, the bottom support plate and the base form a receiving cavity, and the receiving cavity is communicated with the cavity inside the clamping rod, and the bottom end of the light guide rod abuts against the bottom of the receiving cavity; the through hole B and the receiving cavity are used to block benzoic acid crystals and penetrate the proton exchange liquid.

[0016] Furthermore, the transceiver module includes a collimated LED light source, a beam splitter prism, a C-lens focusing lens, a photodetector and a signal processing circuit. A beam splitter prism is provided above the light guide rod, and the beam splitter prism is arranged below the collimated LED light source. A C-lens focusing lens is provided on the top of the light guide rod, and a photodetector is provided on the right side of the beam splitter prism. The photodetector is connected to the signal processing circuit unit. The collimated LED light source provides incident light to the incident end of the light source through the beam splitter prism. The photodetector detects reflected light from the reflected light detection end through the beam splitter prism. The C-lens focusing lens is used to converge light, and then the reflected light power is detected through the signal processing circuit to know whether the probe detects the liquid level.

[0017] The photoelectric detector sends the reflected light signal to the photoelectric conversion circuit, converts the light signal into an electrical signal, then sends the electrical signal to the amplifier circuit, amplifies the electrical signal, and finally sends the amplified electrical signal to the data acquisition and analysis circuit, converts the electrical signal from an analog quantity to a digital quantity, and analyzes the signal to obtain information on whether the liquid level is detected.

[0018] Furthermore, the signal processing circuit includes a photoelectric conversion circuit, an amplifying circuit and a data acquisition and analysis circuit, which are connected in sequence, and the photoelectric conversion circuit is connected to a photodetector.

[0019] Furthermore, the end face of the C-lens focusing lens close to the beam splitter prism is provided with an inclination angle of 7.5° to 8.5°, and the inclination angle is set for anti-reflection. The beam splitter prism is a semi-reflective and semi-transparent mirror. The bottom end of the light guide rod is a plane, and the bottom end of the light guide rod is tightly attached to the bottom of the accommodating cavity, serving as a probe to detect the liquid level of the proton exchange fluid.

[0020] Furthermore, the light guide rod is provided with a core and cladding which are the same as those of the optical fiber.

[0021] Furthermore, the substrate slot block, the clamping rod and the light guide rod are all made of quartz glass.

[0022] (1) The liquid level detection fixture for proton exchange described in the present invention is designed based on the principle that the reflectivity of light at the glass-air interface and at the glass-benzoic acid melt interface is different. It can solve the problem of large temperature fluctuations during proton exchange and improve the consistency of manufacturing lithium niobate waveguide chips.

[0023] (2) The liquid level detection fixture for proton exchange described in the present invention has a simple structure, is easy to assemble, has a reliable principle, is easy to use, and can be reused after being cleaned with alcohol. The substrate card slot block, the clamping rod, the light guide rod, and the transceiver module can all be reused, thereby reducing the cost of use.

[0024] (3) The liquid level detection fixture for proton exchange described in the present invention can be used in harsh environments such as high temperature and high pressure, flammable and explosive, and strong magnetic fields. The materials used to make the fixture do not react with the benzoic acid melt and can participate in proton exchange throughout the use process.

[0025] (4) The method for using the detection fixture of the present invention can reduce the temperature fluctuation caused by the temperature difference between the chip and the exchange solution when the chip is placed in the proton exchange solution, thereby improving the control accuracy of the proton exchange. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Attached Figure 1 It is a schematic structural diagram of the liquid level detection fixture for proton exchange according to the present invention.

[0027] Attached Figure 2 It is a structural schematic diagram of the substrate slot block of the present invention.

[0028] Attached Figure 3 It is a schematic structural diagram of the clamping rod of the present invention.

[0029] Attached Figure 4 It is a schematic diagram of the top view of the clamping rod of the present invention.

[0030] Attached Figure 5 It is a structural schematic diagram of the light transmission and transceiver module in the light guide rod of the present invention.

[0031] Attached Figure 6 It is a bottom view structural schematic diagram of the clamping rod of the present invention.

[0032] In the attached figure:

[0033] 1. Substrate card slot block, 2. Clamping rod, 3. Light guide rod, 4. Transceiver module, 5. Collimated LED light source, 6. Incident light, 7. C-lens focusing lens, 8. Reflected light, 9. Beam splitter prism, 10. Photodetector;

[0034] 101. second mounting plate, 102. groove, 103. through hole A, 104. first mounting plate, 105. mounting hole, 106. mounting block;

[0035] 201. Through hole B, 202. Base, 203. Receiving cavity, 204. Cylindrical hollow column cavity, 205. Crescent-shaped hollow column cavity, 206. Bottom supporting plate. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with specific implementation methods. The accompanying drawings are only used for exemplary descriptions and are only schematic diagrams, not actual drawings, and cannot be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the accompanying drawings may be omitted.

[0037] The present invention provides a liquid level detection fixture for proton exchange, which is mainly used in the proton exchange process of lithium niobate waveguide chip production and alarming the liquid level of proton exchange liquid;

[0038] like Figures 1 to 3As shown, the liquid level detection fixture for proton exchange includes a substrate slot block 1, a clamping rod 2, a light guide rod 3 and a transceiver module 4, wherein the substrate slot block 1 is provided at the lower portion of the clamping rod 2, the light guide rod 3 is arranged inside the clamping rod 2, and the transceiver module 4 is provided on the top of the light guide rod 3; a base 202 is provided at the bottom end of the clamping rod 2, a bottom support plate 206 is provided below the base 202, a through hole B201 for penetrating proton exchange liquid is provided on the bottom support plate 206, and the base 202 is used to position the substrate slot block 1 so that the substrate slot block 1 can be nested on the clamping rod 2.

[0039] As a further improvement of the above embodiment, the substrate slot block 1 includes a first mounting plate 104, a second mounting plate 101 and a mounting block 106, the mounting block 106 is provided with a hollow mounting hole 105, the first mounting plate 104 is arranged at the upper end of the mounting block 106, and the middle of the first mounting plate 104 is provided with a through hole communicating with the mounting hole 105, the second mounting plate 101 is arranged at the lower end of the mounting block 106, and the middle of the second mounting plate 101 is provided with a through hole communicating with the mounting hole 105, the first mounting plate 104, the mounting block 106, and the second mounting plate 101 are connected in sequence to form a substrate slot block 1 with an annular groove 102 in the middle, the substrate slot block 1 is sleeved on the lower part of the clamping rod 2 through the mounting hole 105, and the diameter of the mounting hole 105 is slightly larger than that of the clamping rod 2 for easy installation.

[0040] A groove 102 for loading a lithium niobate substrate is provided near the edge of the lower surface of the first mounting plate 104 and the upper surface of the second mounting plate 101. A plurality of through holes A103 are provided on both the first mounting plate 104 and the second mounting plate 101. The through holes A103 are used to reduce the buoyancy of the proton exchange liquid on the fixture when the fixture is immersed.

[0041] As a further improvement of the above embodiment, a cavity with openings at both ends is provided in the clamping rod 2, and the cavity includes a cylindrical hollow column cavity 204 and a crescent-shaped hollow column cavity. The design of the crescent-shaped hollow column cavity 205 can reduce the weight of the clamping rod 2 and save materials.

[0042] The light guide rod 3 is arranged in the cylindrical hollow column cavity 204, the bottom support plate 206 and the base 202 form a receiving cavity 203, and the receiving cavity 203 is communicated with the cavity inside the clamping rod 2, and the bottom end of the light guide rod 3 is abutted against the bottom of the receiving cavity 203; the bottom end of the light guide rod 3 is close to the bottom of the receiving cavity 203, and the benzoic acid vapor will flow upward, and will not form crystals at the bottom end of the light guide rod 3 to affect the detection. The through hole B201 and the receiving cavity 203 are used to block benzoic acid crystals and penetrate the proton exchange liquid.

[0043] As a further improvement of the above-mentioned embodiment, the transceiver module 4 includes a collimated LED light source 5, a beam splitter prism 9, a C-lens focusing lens 7, a photodetector 10 and a signal processing circuit. The beam splitter prism 9 is provided above the light guide rod 3, and the beam splitter prism 9 is arranged below the collimated LED light source 5. The top of the light guide rod 3 is provided with a C-lens focusing lens 7, and the right side of the beam splitter prism 9 is provided with a photodetector 10. The photodetector 10 is connected to the signal processing circuit unit. The collimated LED light source 5 provides incident light 6 to the incident end of the light source through the beam splitter prism 9. The photodetector 10 detects the reflected light 8 from the detection end of the reflected light 8 through the beam splitter prism 9. The C-lens focusing lens 7 is used to converge the light, and then the power of the reflected light 8 is detected through the signal processing circuit to know whether the probe detects the liquid level.

[0044] The photoelectric detector 10 sends the signal of the reflected light 8 to the photoelectric conversion circuit, converts the optical signal into an electrical signal, and then sends the electrical signal to the amplifier circuit to amplify the electrical signal. Finally, the amplified electrical signal is sent to the data acquisition and analysis circuit, which converts the electrical signal from an analog quantity to a digital quantity, and analyzes the signal to obtain information on whether the liquid level is detected.

[0045] As a further improvement of the above embodiment, the signal processing circuit includes a photoelectric conversion circuit, an amplifying circuit and a data acquisition and analysis circuit, which are connected in sequence, and the photoelectric conversion circuit is connected to the photodetector 10. The photoelectric conversion circuit, the amplifying circuit and the data acquisition and analysis circuit all adopt the photoelectric conversion circuit, the amplifying circuit and the data acquisition and analysis circuit commonly used in the prior art.

[0046] As a further improvement of the above-mentioned embodiment, the end face of the C-lens focusing lens 7 close to the beam splitter prism 9 is provided with an inclination angle of 8°, and the setting of the inclination angle is used for anti-reflection. The beam splitter prism 9 is a semi-reflective and semi-transparent mirror. The bottom end of the light guide rod 3 is a plane, and the bottom end of the light guide rod 3 is tightly attached to the bottom of the accommodating cavity 203, serving as a probe to detect the liquid level of the proton exchange fluid.

[0047] like Figure 4 and Figure 6 As shown, as a further improvement of the above-mentioned embodiment, the light guide rod 3 is provided with a core plus cladding same as that of the optical fiber, and the light beam is conducted by utilizing the principle of total reflection. The C-lens focusing lens 7 at the upper end of the light guide rod 3 has an inclination angle of 8° near the end face of the beam splitter prism 9 for anti-reflection.

[0048] As a further improvement of the above embodiment, the substrate slot block 1, the clamping rod 2 and the light guide rod 3 are all made of quartz glass.

[0049] The working principle of the liquid level detection fixture for proton exchange described in the present invention is as follows:

[0050] Install the chip in the groove on the substrate slot block at the bottom of the detection fixture, and slowly place the lower end of the liquid level detection fixture used for proton exchange into the exchange furnace filled with proton exchange liquid. When the reflected light power changes significantly, the fixture stops moving down, indicating that the fixture has contacted the liquid surface. The heat is quickly evenly distributed through heat conduction, so that the temperature of the chip is close to the exchange liquid. However, the chip does not contact the exchange liquid, and the exchange does not occur. Wait until the chip temperature is close to the exchange liquid (about 1-3 minutes, estimated based on the thermal model and specific experience), then slowly move the fixture and slowly soak the chip in the exchange liquid. The above operation process can greatly reduce the range of temperature fluctuations during the exchange process and improve the control accuracy of the exchange amount.

[0051] The transceiver module 4 includes a collimated LED light source 5, a beam splitter prism 9, a C-lens focusing lens 7 and a photodetector 10. Figure 5 As shown, the collimated LED light source 5 provides incident light 6 to the liquid level detection fixture via the beam splitter prism 9, and the photodetector 10 detects the reflected light 8 from the light guide rod 3 via the beam splitter prism 9;

[0052] A C-lens condenser lens 7 is placed between the top of the light guide rod 33 and the beam splitter prism 9 to converge the light, and the photodetector 10 sends the detected reflected light 8 signal to the photoelectric conversion circuit.

[0053] When the bottom end of the light guide rod 3 is in the air, part of the light in the light guide rod 3 will be totally reflected at the end surface and return to the detector to generate a signal;

[0054] When the bottom end of the light guide rod 3 is immersed in the proton exchange liquid, the light in the light guide rod 3 will be reflected by Fresnel at the end face, and part of the light power will be transmitted into the exchange liquid along with the refracted light. The refractive index of air is n 0 =1.0, the material of the light guide rod 3 is quartz glass, the refractive index of quartz glass is n 1 =1.46, and the proton exchange liquid is benzoic acid melt, and its refractive index is n 2 =1.54.

[0055] For normally incident light, when reflection occurs at the quartz glass / air interface, the reflectivity calculation formula is given by the following formula:

[0056]

[0057] When reflection occurs at the interface of quartz glass / benzoic acid melt, the reflectivity calculation formula is given by the following formula:

[0058]

[0059] Through calculation and analysis, it can be known that when the light is totally reflected at the quartz glass / air interface, the reflectivity is 3.5%, and when the Fresnel reflection occurs at the quartz glass / benzoic acid melt interface, the reflectivity is 0.07%. The light power received by the detector is greatly reduced. By detecting the power of the reflected light 8 in the light guide rod 3, it can be known whether the liquid level of the proton exchange liquid is detected.

[0060] Then the photodetector 10 sends the signal of the reflected light 8 to the photoelectric conversion circuit, converts the optical signal into an electrical signal, and then sends it to the amplifier circuit to amplify the electrical signal, and finally sends it to the data acquisition and analysis circuit to convert the electrical signal from an analog quantity to a digital quantity, and analyzes the signal to obtain information on whether the liquid level is detected.

[0061] (1) The liquid level detection fixture for proton exchange described in the present invention is designed based on the principle that the reflectivity of light at the glass-air interface and at the glass-benzoic acid melt interface is different. Combined with the use method, it can solve the problem of large temperature fluctuations during the proton exchange process and improve the consistency of manufacturing lithium niobate waveguide chips.

[0062] (2) The liquid level detection fixture for proton exchange described in the present invention has a compact structure, simple assembly, reliable principle, and is easy to use. It can be reused after being cleaned with alcohol. The substrate card slot block 1, the clamping rod 2, the light guide rod 3, and the transceiver module 4 can all be reused, thereby reducing the cost of use.

[0063] (3) The liquid level detection fixture for proton exchange described in the present invention can be used in harsh environments such as high temperature and high pressure, flammable and explosive, and strong magnetic fields. The materials used to make the fixture do not react with the benzoic acid melt and can participate in proton exchange throughout the use process.

[0064] Obviously, the above embodiments are merely examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A liquid level detection fixture for proton exchange, comprising a substrate slot block, a clamping rod, a light guide rod and a transceiver module, characterized in that: The lower part of the clamping rod is provided with a substrate card slot block, the light guide rod is arranged inside the clamping rod, and the top of the light guide rod is provided with a transceiver module; the bottom end of the clamping rod is provided with a base, and a bottom support plate is provided below the base, and the bottom support plate is provided with a through hole B for permeating a proton exchange liquid; The clamping rod is provided with a cavity with two ends opened, the cavity includes a cylindrical hollow column cavity and a crescent-shaped hollow column cavity, the light guide rod is arranged in the cylindrical hollow column cavity, the bottom support plate and the base form a receiving cavity, and the receiving cavity is communicated with the cavity inside the clamping rod, and the bottom end of the light guide rod abuts against the bottom of the receiving cavity; the bottom end of the light guide rod is a plane, and the bottom end of the light guide rod is tightly attached to the bottom of the receiving cavity; The substrate card slot block comprises a first mounting plate, a second mounting plate and a mounting block, the mounting block is provided with a hollow mounting hole, the first mounting plate is arranged at the upper end of the mounting block, and the middle part of the first mounting plate is provided with a through hole communicating with the mounting hole, the second mounting plate is arranged at the lower end of the mounting block, and the middle part of the second mounting plate is provided with a through hole communicating with the mounting hole, the first mounting plate, the mounting block and the second mounting plate are sequentially connected to form a substrate card slot block with an annular groove in the middle part, the substrate card slot block is sleeved on the lower part of the clamping rod through the mounting hole; the lower surface of the first mounting plate and the upper surface of the second mounting plate are provided with a groove for loading the substrate near the edge, and the first mounting plate and the second mounting plate are both provided with a plurality of through holes A; The transceiver module includes a collimated LED light source, a beam splitter prism, a C-lens focusing lens, a photodetector and a signal processing circuit. The beam splitter prism is arranged above the light guide rod, and the beam splitter prism is arranged below the collimated LED light source. The top of the light guide rod is provided with a C-lens focusing lens, and a photodetector is arranged on the right side of the beam splitter prism. The photodetector is connected to the signal processing circuit unit.

2. The liquid level detection fixture for proton exchange according to claim 1, characterized in that: The signal processing circuit comprises a photoelectric conversion circuit, an amplifying circuit and a data acquisition and analysis circuit, which are connected in sequence, and the photoelectric conversion circuit is connected to a photodetector.

3. The liquid level detection fixture for proton exchange according to claim 1, characterized in that: The end surface of the C-lens condenser lens close to the beam splitter prism is provided with an inclination angle of 7.5° to 8.5°.

4. The liquid level detection fixture for proton exchange according to any one of claims 1 to 3, characterized in that: The light guide rod is provided with a core and a cladding layer which are the same as those of the optical fiber.

5. The liquid level detection fixture for proton exchange according to claim 4, characterized in that: The substrate slot block, the clamping rod and the light guide rod are all made of quartz glass.

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