Apparatus for pulsed spray manufacturing of humidity sensor chips

Abstract

A device for pulsed spray type manufacturing of humidity sensor chip, comprising a cavity for accommodating a rectangular substrate, a first atomizing nozzle and a second atomizing nozzle are oppositely arranged inside the cavity; the first atomizing nozzle and the second atomizing nozzle are respectively used for alternately and pulsed atomizing spraying a first humidity sensitive material and a second humidity sensitive material; the resistivity of the first humidity sensitive material and the second humidity sensitive material is sensitive to the environmental humidity; the first atomizing nozzle is used for pulsed atomizing spraying the first humidity sensitive material to the rectangular substrate, and the distribution density of the first humidity sensitive material deposited on the substrate gradually decreases; the second atomizing nozzle is used for pulsed atomizing spraying the second humidity sensitive material to the rectangular substrate, and the distribution density of the second humidity sensitive material deposited on the substrate gradually decreases. The first atomizing nozzle, the second atomizing nozzle, the first jet type atomizer and the second jet type atomizer are fixedly arranged, which avoids the problem of easy fatigue damage of the manufacturing device.

Description

Technical Field

[0001] This invention relates to an apparatus for manufacturing a humidity sensor chip, and more particularly to an apparatus for manufacturing a humidity sensor chip using a pulse spray method. Background Technology

[0002] Finished humidity sensors made with specific humidity-sensitive materials are often only suitable for measuring humidity within a specific range. They only have good accuracy within a certain humidity range; outside this range, the accuracy becomes extremely unreliable. To achieve a wide humidity measurement range, humidity sensors with different measurement ranges are usually used in parallel, so that the overall humidity sensor system can cover the humidity measurement range of each individual sensor. However, this approach brings the problems of high cost and complex manufacturing process. Balancing a wide humidity measurement range with low cost and manufacturing complexity is a truly challenging problem.

[0003] On the other hand, in our prior patent application CN2021113843119 "A method for manufacturing a humidity sensor chip", the same atomizing nozzle is used to alternately atomize and spray a first humidity-sensitive material and a second humidity-sensitive material. Each pulse atomization spray is switched by a micro-valve to deliver the solution of the first humidity-sensitive material or the solution of the second humidity-sensitive material to the atomizing nozzle. This will make the atomizing nozzle easily cross-contaminated. In addition, since the atomizing nozzle needs to move alternately above the first edge of the substrate and above the second edge of the substrate during operation, and adjust the spray direction to point obliquely downwards to the second edge and the first edge of the rectangular substrate respectively, the frequent movement of the atomizing nozzle will make it very easy to fatigue and damage.

[0004] The technical solution of the present invention is a further development based on our prior invention patent application CN202111158676X "Wide Measurement Range Resistive Humidity Sensor" and prior invention patent application CN2021113843119 "A Method for Manufacturing a Humidity Sensor Chip". Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an apparatus for manufacturing humidity sensor chips using pulse spray technology. The purpose of this apparatus is to achieve a wide humidity measurement range, significantly reduce manufacturing process complexity and costs, and extend the service life of the manufacturing device.

[0006] The technical solution involves manufacturing a humidity sensor using a resistive humidity-sensitive material. The humidity-sensitive material is deposited on a rectangular substrate, and the rectangular substrate has interdigitated electrodes. The signals collected by the interdigitated electrodes can be used to acquire ambient humidity signals. The humidity sensor chip includes a rectangular substrate with opposing first and second edges, and opposing third and fourth edges. A pair of interdigitated electrodes are fabricated on the rectangular substrate, which has opposing first and second edges, and opposing third and fourth edges.

[0007] The apparatus of the present invention for manufacturing a humidity sensor chip by pulse spray includes a cavity for accommodating a rectangular substrate, wherein a first atomizing nozzle and a second atomizing nozzle are disposed opposite to each other inside the cavity; the first atomizing nozzle and the second atomizing nozzle are used to alternately pulse spray a first humidity-sensitive material and a second humidity-sensitive material; the resistivity of the first humidity-sensitive material and the second humidity-sensitive material is sensitive to ambient humidity.

[0008] The cavity comprises a top plate, a bottom porous filter, and a cylindrical body, with the bottom porous filter used to fix and place a rectangular substrate.

[0009] The left and right side walls of the cylinder are symmetrically provided with a first atomizing pipe and a second atomizing pipe, respectively. A first atomizing nozzle and a second atomizing nozzle are respectively provided at one end of the first atomizing pipe and the second atomizing pipe. The first atomizing nozzle points obliquely downward from above the first edge of the rectangular substrate to the second edge of the rectangular substrate; the second atomizing nozzle points obliquely downward from above the second edge of the rectangular substrate to the first edge of the rectangular substrate.

[0010] The first atomizing nozzle is used to pulse-atomize and spray a first humidity-sensitive material onto a rectangular substrate. The atomized mist containing the first humidity-sensitive material has a concentration gradient, which causes the distribution density of the first humidity-sensitive material deposited on the substrate to gradually decrease in the direction away from the first atomizing nozzle.

[0011] The second atomizing nozzle is used to pulse-atomize and spray a second humidity-sensitive material onto a rectangular substrate. The atomized mist containing the second humidity-sensitive material has a concentration gradient, which causes the distribution density of the second humidity-sensitive material deposited on the substrate to gradually decrease in the direction away from the second atomizing nozzle.

[0012] The fabrication of a humidity sensor chip using the aforementioned apparatus for pulse spray manufacturing includes the following steps:

[0013] A. Fabricate a pair of interdigitated electrodes on a rectangular substrate;

[0014] B. A humidity-sensitive material is fabricated on the rectangular substrate with a pair of interdigitated electrodes attached, obtained in step A, as specifically implemented below:

[0015] Ba. A first atomizing nozzle is used to pulse-atomize and spray a first humidity-sensitive material onto the rectangular substrate from above the first edge and diagonally downwards toward the second edge of the rectangular substrate. The atomized mist containing the first humidity-sensitive material has a concentration gradient, which causes the distribution density of the first humidity-sensitive material deposited on the substrate to gradually decrease from the first edge to the second edge.

[0016] Bb. A second atomizing nozzle is used to pulse-atomize and spray a second humidity-sensitive material onto the rectangular substrate from above the second edge and diagonally downwards toward the first edge of the rectangular substrate. The atomized mist containing the second humidity-sensitive material has a concentration gradient, which causes the distribution density of the second humidity-sensitive material deposited on the substrate to gradually decrease from the second edge to the first edge.

[0017] Steps Ba and Bb are performed alternately, and the number of repetitions depends on the needs.

[0018] C. Under the control of the temperature controller, the heater heats up to the set temperature to dry and cure the humidity-sensitive material;

[0019] D. Weld the electrode leads to complete the manufacturing of the humidity sensor chip.

[0020] Electrodes and humidity-sensitive material are attached to the rectangular substrate. In step A, the interdigitated lines of the interdigitated electrodes are located between the third and fourth edges of the substrate and are parallel to the third and fourth edges of the substrate. The two lead-out lines of a pair of interdigitated electrodes are parallel to the first and second edges of the substrate and are close to the first and second edges of the substrate, respectively. The two lead-out lines are respectively provided with lead-out pads.

[0021] The first humidity-sensitive material and the second humidity-sensitive material have different surface resistivity-humidity characteristic curves, resulting in different optimal humidity sensing sensitivities.

[0022] The composite humidity-sensitive material formed by alternating steps Ba and Bb several times from the first edge to the second edge, and the first humidity-sensitive material and the second humidity-sensitive material, exhibit a gradual change in surface resistivity-humidity characteristic curve along the length of the electrode. This results in the composite humidity-sensitive material having different optimal humidity sensitivity at different locations, ultimately leading to a resistive humidity sensor with a wide measurement range.

[0023] Both the first humidity-sensitive material and the second humidity-sensitive material are nanomaterials, which are uniformly dispersed in a solvent to form a solution. The first jet atomizer and the second jet atomizer are used to hold the solutions formed by the first humidity-sensitive material and the second humidity-sensitive material being uniformly dispersed in the solvent, and to atomize and spray the solutions when needed.

[0024] Along the length of the electrode, the resistivity-humidity characteristic curve of the humidity-sensitive material gradually changes. The humidity-sensitive material at different locations responds sensitively to different ambient humidity levels, achieved through its composition and / or specific surface area and / or nanoscale size and / or microstructure. For example, by gradually varying the composition of the humidity-sensitive material along the length of the electrode, the differences in composition at different locations result in a gradual change in the resistivity-humidity characteristic curve. Each humidity-sensitive material at a different location responds sensitively to a different range of humidity changes, meaning each component performs its specific function. This gradual change in the resistivity-humidity characteristic curve allows the humidity-sensitive resistor between a pair of electrodes to respond sensitively to a wide range of humidity variations.

[0025] The technical solution of this invention is a further development based on our prior patent applications CN202111158676X "Wide Measurement Range Resistive Humidity Sensor" and CN2021113843119 "A Method for Manufacturing a Humidity Sensor Chip". The technical principles can be found in the prior patent application CN202111158676X, and will not be repeated extensively in this patent application. The content of the specification in the prior patent application CN202111158676X can be considered part of this patent, and the applicant reserves the right to incorporate part or all of the content of the specification in CN202111158676X when necessary.

[0026] Humidity-sensitive materials with different compositions, microstructures, and specific surface areas will exhibit different optimal humidity sensing ranges. The specific sensing range can be determined by rationally selecting between two humidity-sensitive materials based on actual conditions.

[0027] By employing the above-described configuration, a single humidity sensor can respond to a wide range of humidity variations, thereby achieving a broad humidity measurement range. As can be seen from the core concept of this invention, it provides a resistive humidity sensor with a wide measurement range. While maintaining accuracy, it achieves a wide humidity measurement range using only a single humidity sensor, further reducing manufacturing costs and the complexity of the humidity sensor. Furthermore, since the first atomizing nozzle, second atomizing nozzle, first jet atomizer, and second jet atomizer in this invention are all fixedly positioned, there is no need for frequent back-and-forth movement of their positions or angles, thus avoiding the problem of fatigue damage to the manufacturing equipment caused by frequent movement.

[0028] The inventors have now explained in detail the working principle, technical solution, and technical effects of this invention. This instruction manual The content not described in detail belongs to the prior art known to those skilled in the art. . Attached Figure Description

[0029] Figure 1 Side view of an apparatus used for manufacturing humidity sensor chips using pulse spray technology;

[0030] Figure 2 : Schematic diagram of the connection between the device used for manufacturing humidity sensor chips using pulse spray and the temperature controller;

[0031] Figure 3 : Figure 2 Top view of the clamping device;

[0032] Figure 4 A humidity sensor chip according to the present invention;

[0033] Figure 5 The first jet atomizer and the second jet atomizer in this invention.

[0034] In the diagram: 1 is a stud, 2 is an upper cover plate, 3 is a lower cover plate, 4 is a top plate, 5 is a bottom porous filter, 6 is an upper nut, 7 is a lower nut, 8 is a bolt, 9 is a washer, 10 is a heater, 11 is a thermocouple, 12 is the first atomizing pipe, 13 is the second atomizing pipe, 14 is the suction pipe, 15 is the first atomizing nozzle, 16 is the second atomizing nozzle, 17 is a clamping device, 18 is a rectangular substrate, 19 is a cylinder, 20 is a temperature controller, 21 is the first edge, 22 is the second edge, 23 is the third edge, 24 is the fourth edge, 25a is the outlet of the first jet atomizer, 25b is the outlet of the second jet atomizer, 26a is the outlet of the second jet atomizer. 26b is the gas flow meter inlet of the first jet atomizer, 27a is the variable air intake port of the first jet atomizer, 27b is the variable air intake port of the second jet atomizer, 28a is the carrier gas injection hole of the first jet atomizer, 28b is the carrier gas injection hole of the second jet atomizer, 29a is the siphon tube of the first jet atomizer, 2ba is the siphon tube of the second jet atomizer, 30a is the liquid storage container of the first jet atomizer, 30b is the liquid storage container of the second jet atomizer, 31a is the filter of the first jet atomizer, and 31b is the filter of the second jet atomizer. Detailed Implementation

[0035] The technical solution of the present invention will be described in detail below with reference to examples.

[0036] See Figure 1-5 The humidity sensor chip of the present invention includes a humidity-sensitive material, a rectangular substrate, and a pair of interdigitated electrodes; both the pair of interdigitated electrodes and the humidity-sensitive material are fabricated on the substrate. The rectangular substrate has a first edge 21 and a second edge 22, a third edge 23 and a fourth edge 24 arranged opposite to each other. The pair of interdigitated electrodes includes a first sub-electrode and a second sub-electrode, the distance between the lead-out lines of the first sub-electrode and the lead-out lines of the second sub-electrode is L, the line spacing between the first sub-electrode and the second sub-electrode is w, and the vertical distance from any point between the lead-out lines of the first sub-electrode and the second sub-electrode is x.

[0037] The humidity sensor chip includes a rectangular substrate 18 on which a pair of interdigitated electrodes are fabricated. The rectangular substrate 18 has a first edge and a second edge, a third edge and a fourth edge that are disposed opposite to each other.

[0038] An apparatus for manufacturing a humidity sensor chip by pulse spraying includes a cavity for accommodating a rectangular substrate 18, and a first atomizing nozzle 15 and a second atomizing nozzle 16 disposed opposite to each other inside the cavity; the first atomizing nozzle 15 and the second atomizing nozzle 16 are respectively used to alternately pulse spray a first humidity-sensitive material and a second humidity-sensitive material; the resistivity of the first humidity-sensitive material and the second humidity-sensitive material is sensitive to ambient humidity.

[0039] The first atomizing nozzle 15 is used to pulse-atomize and spray a first humidity-sensitive material onto the rectangular substrate 18. The atomized mist containing the first humidity-sensitive material has a concentration gradient, so that the distribution density of the first humidity-sensitive material deposited on the substrate gradually decreases in the direction away from the first atomizing nozzle 15.

[0040] The second atomizing nozzle 16 is used to pulse-atomize and spray a second humidity-sensitive material onto the rectangular substrate 18. The atomized mist containing the second humidity-sensitive material has a concentration gradient, which causes the distribution density of the second humidity-sensitive material deposited on the substrate to gradually decrease in the direction away from the second atomizing nozzle 16.

[0041] The cavity consists of a top plate 4, a bottom porous filter 5, and a cylinder 19. The bottom porous filter is used to fix and place the substrate.

[0042] The cavity is fixed in the frame; the frame includes multiple symmetrically arranged studs 1, upper cover plate 2, lower cover plate 3, multiple upper nuts 6, and multiple lower nuts 7. Each stud 1 passes through the upper cover plate 2 and the lower cover plate 3. The upper nuts 6 and lower nuts 7 are fastened to the upper and lower ends of the stud 1, respectively, so that the cavity is fixedly arranged in the space enclosed by multiple symmetrically arranged studs 1, upper cover plate 2, and lower cover plate 3.

[0043] A heater 10 and a thermocouple 11 are installed inside the wall of the cylinder 19. The heater 10 and the thermocouple 11 are electrically connected to a temperature controller 20 to control the temperature inside the cavity. The purpose of controlling the temperature inside the cavity is to allow the solvent in the solution to evaporate more quickly and be rapidly discharged from the cavity by heating to a set temperature, and to dry and cure moisture-sensitive materials.

[0044] The left and right side walls of the cylinder 19 are symmetrically provided with a first atomizing pipe 12 and a second atomizing pipe 13, respectively. A first atomizing nozzle 15 and a second atomizing nozzle 16 are respectively provided at one end of the first atomizing pipe 12 and the second atomizing pipe 13. The first atomizing nozzle 15 extends obliquely downwards from above the first edge of the rectangular substrate 18 towards the second edge of the rectangular substrate 18; the second atomizing nozzle 16 extends obliquely downwards from above the second edge of the rectangular substrate 18 towards the first edge of the rectangular substrate 18. The other ends of the first atomizing pipe 12 and the second atomizing pipe 13 are respectively connected to the outlet 25a of the first jet atomizer and the outlet 25b of the second jet atomizer. The first jet atomizer and the second jet atomizer are used to hold solutions formed by uniformly dispersing the first humidity-sensitive material and the second humidity-sensitive material in a solvent, respectively, and to atomize and spray the solutions when needed.

[0045] like Figure 5 As shown, the first jet atomizer includes an outlet 25a, a gas flow meter inlet 26a, a variable air intake port 27a, a carrier gas injection hole 28a, a siphon tube 29a, a liquid storage container 30a, and a filter 31a; the second jet atomizer includes an outlet 25b, a gas flow meter inlet 26b, a variable air intake port 27b, a carrier gas injection hole 28b, a siphon tube 29b, a liquid storage container 30b, and a filter 31b. The structure of the second jet atomizer is exactly the same as that of the first jet atomizer.

[0046] The storage container holds the solution containing diluted humidity-sensitive materials, the filter filters out excessively large particles of the humidity-sensitive materials from the solution, the outlet of the jet atomizer sprays out aerosol, the variable air inlet controls the carrier gas flow rate and velocity, the gas flow meter measures the gas flow rate, and the carrier gas injection orifice sprays the carrier gas at high speed. The solution is extracted and atomized through the siphon effect of the siphon tube. The principle of the jet atomizer in this invention is compression atomization, also called jet atomization. It is based on the Venturi principle, using high-pressure carrier gas to form a high-speed airflow through a narrow tube. The resulting negative pressure carries the liquid and sprays it onto the obstruction. Under high-speed impact, the liquid splashes outwards, turning droplets into atomized particles that are ejected from the outlet tube.

[0047] Two clamping devices 17 are symmetrically arranged between the bottom porous filter screen 5 and the bottom end of the cylinder 19 for fixing the rectangular substrate 18. The rectangular substrate 18 is attached to the bottom porous filter screen 5, and the clamping device 17 clamps the rectangular substrate 18 and keeps it in a flat state.

[0048] Preferably, a first automatic valve and a second automatic valve are respectively provided in the middle of the first atomizing pipe 12 and the second atomizing pipe 13. The first automatic valve and the second automatic valve are used to control the opening and closing of the first atomizing pipe 12 and the second atomizing pipe 13, respectively. During operation, the first automatic valve and the second automatic valve switch on and off alternately, so that the first humidity-sensitive material and the second humidity-sensitive material are pulsed atomized and sprayed out. The first automatic valve and the second automatic valve are not shown in the figure.

[0049] Preferably, the first automatic valve and the second automatic valve are switched on and off alternately by a controller. The controller is not shown in the figure.

[0050] Preferably, when the upper nut 6 and the lower nut 7 are fastened to the upper and lower ends of the stud 1 respectively, a washer 9 is also provided.

[0051] The lower cover plate 3 has a through hole in the middle, and an air extraction pipe 14 is installed in the through hole. The air extraction pipe is connected to a micro vacuum pump and works in conjunction with the lower porous filter screen so that the air pressure inside the cavity is lower than the external atmospheric pressure when the device is working, forming a downward airflow. The mist of the humidity-sensitive material is more likely to flow and deposit onto the rectangular substrate 18, rather than being scattered everywhere.

[0052] Preferably, the extraction pipeline is threadedly connected to the miniature vacuum pump via bolt 8. The miniature vacuum pump is not shown in the figure.

[0053] Preferably, the first atomizing nozzle (15) and the second atomizing nozzle (16) are located directly above the first edge and the second edge of the rectangular substrate (18), respectively.

[0054] The manufacturing method of a humidity sensor chip includes the following steps:

[0055] A. Fabricate a pair of interdigital electrodes on a rectangular substrate; in practice, step A can be carried out by any one of sputtering, vapor deposition, mask printing, chemical electroplating, or screen printing to complete the fabrication of the interdigital electrodes.

[0056] B. A humidity-sensitive material is fabricated on the rectangular substrate with a pair of interdigitated electrodes attached, obtained in step A, as specifically implemented below:

[0057] Ba. A first atomizing nozzle is used to pulse-atomize and spray a first humidity-sensitive material onto the rectangular substrate from above the first edge and diagonally downwards toward the second edge of the rectangular substrate. The atomized mist containing the first humidity-sensitive material has a concentration gradient, which causes the distribution density of the first humidity-sensitive material deposited on the substrate to gradually decrease from the first edge to the second edge.

[0058] Bb. A second atomizing nozzle is used to pulse-atomize and spray a second humidity-sensitive material onto the rectangular substrate from above the second edge and diagonally downwards toward the first edge of the rectangular substrate. The atomized mist containing the second humidity-sensitive material has a concentration gradient, which causes the distribution density of the second humidity-sensitive material deposited on the substrate to gradually decrease from the second edge to the first edge.

[0059] Steps Ba and Bb are performed alternately, and the number of repetitions depends on the needs.

[0060] C. Under the control of the temperature controller, the heater heats up to the set temperature to dry and cure the humidity-sensitive material;

[0061] D. Weld the electrode leads to complete the manufacturing of the humidity sensor chip.

[0062] Electrodes and humidity-sensitive material are attached to a rectangular substrate. In step A, the interdigitated lines of the interdigitated electrodes are located between the third edge 23 and the fourth edge 24 of the substrate, and are parallel to the third edge 23 and the fourth edge 24 of the substrate. The two lead-out lines of a pair of interdigitated electrodes are parallel to the first edge 21 and the second edge 22 of the substrate, and are close to the first edge 21 and the second edge 22 of the substrate, respectively. Each lead-out line is provided with a lead-out pad. The square areas on the two sub-electrodes in the figure are the lead-out pads.

[0063] Preferably, both the first humidity-sensitive material and the second humidity-sensitive material are nanomaterials, each uniformly dispersed in a solvent to form a solution for pulsed atomization spraying.

[0064] The first and second humidity-sensitive materials are characterized by their water-absorbing properties, absorbing moisture from the ambient air, causing their resistivity to change with the moisture content. Both the first and second humidity-sensitive materials can be organic composites, inorganic composites, or organic / inorganic composites. The resistivity of both materials changes with humidity.

[0065] For example, the first humidity-sensitive material and the second humidity-sensitive material are selected from any two of the following: SnO2 nanomaterials, Fe3O4 nanomaterials, Sb2O3 nanomaterials, ZnO nanomaterials, In2O3 nanomaterials, TiO2 nanowires, PdCl2 nanomaterials, Cu2O nanomaterials, WO3 nanomaterials, CeO2 nanomaterials, MnWO4 powder, NiWO4 powder, ZnCrO4 powder, MgCr2O4 powder, polypyrrole, polyvinyl dioxythiophene, sodium polystyrene sulfonate, dimethylaminoethyl methacrylate brominated n-butane quaternary ammonium salt (MEBA), and active siloxane monomer—γ-methacryloyloxypropyltrimethoxysilane (KH570).

[0066] The humidity-sensitive material can also be any other known material with humidity-sensitive properties, as long as the selected first and second humidity-sensitive materials have different humidity-sensitive characteristic curves, that is, different optimal humidity sensing ranges. The greater the difference in the optimal humidity sensing ranges of the two humidity-sensitive materials, the wider the humidity measurement range of the final humidity sensor obtained by this invention.

[0067] The composite humidity-sensitive material formed by alternating steps Ba and Bb several times from the first edge 1 to the second edge 2, and the first humidity-sensitive material and the second humidity-sensitive material, exhibit a gradual change in surface resistivity-humidity characteristic curve along the length of the electrode, resulting in different optimal humidity-sensing sensitivities at different locations; ultimately, a resistive humidity sensor with a wide measurement range is obtained.

[0068] like Figure 4 As shown, point Surface resistivity-humidity function of humidity-sensitive materials The partial derivative of surface resistivity with humidity Let x represent the humidity sensitivity of the surface resistivity at point x as a function of humidity. This represents the function curve showing the relationship between the humidity sensitivity of a humidity-sensitive material and the humidity h. The peak value of the function curve represents the optimal humidity sensitivity of the humidity-sensitive material at point x. Therefore: from the near end to the far end, the humidity-sensitive material... The peak value of the function curve varies with Gradually moving; in the above formula R Indicates the surface resistivity of humidity-sensitive materials. Indicates humidity.

[0069] A pair of interdigitated electrodes includes a first sub-electrode and a second sub-electrode. The distance between the lead lines of the first sub-electrode and the lead lines of the second sub-electrode is L, and the line spacing between the first sub-electrode and the second sub-electrode is w. At any point between the lead lines of the first sub-electrode and the second sub-electrode, at a perpendicular distance x from the lead line of the first sub-electrode, the surface resistivity R of the composite humidity-sensitive material is a function of humidity h and distance x. If the resistance of the humidity-sensitive material at any point x of the first and second sub-electrodes is regarded as Rx, then the total resistance between a pair of interdigitated electrodes is equivalent to the parallel connection of humidity-sensitive resistors at countless locations.

[0070] As the distribution density of the first humidity-sensitive material deposited on the substrate gradually decreases from the first edge 1 to the second edge 2, the distribution density of the second humidity-sensitive material deposited on the substrate gradually increases, and the composition of the humidity-sensitive material changes continuously. The total parallel resistance can be expressed in integral form.

[0071] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. An apparatus for manufacturing a humidity sensor chip by pulse spraying, the humidity sensor chip comprising a rectangular substrate (18) having a first edge and a second edge disposed opposite to each other; Its features are: The apparatus for manufacturing humidity sensor chips by pulse spray includes a cavity for accommodating a rectangular substrate (18), a first jet atomizer, and a second jet atomizer. The cavity contains a first atomizing nozzle (15) and a second atomizing nozzle (16) arranged opposite to each other. The first atomizing nozzle (15) and the second atomizing nozzle (16) are located directly above the first edge and the second edge of the rectangular substrate (18), respectively. The first atomizing nozzle (15) and the second atomizing nozzle (16) are used to alternately pulse-atomize and spray the first humidity-sensitive material and the second humidity-sensitive material. The resistivity of the first humidity-sensitive material and the second humidity-sensitive material is sensitive to the ambient humidity. The first atomizing nozzle (15) is used to pulse atomize and spray the first humidity-sensitive material onto the rectangular substrate (18). The atomized mist containing the first humidity-sensitive material has a concentration gradient, so that the distribution density of the first humidity-sensitive material deposited on the substrate gradually decreases in the direction away from the first atomizing nozzle (15). The second atomizing nozzle (16) is used to pulse atomize and spray the second humidity-sensitive material onto the rectangular substrate (18). The atomized mist containing the second humidity-sensitive material has a concentration gradient, so that the distribution density of the second humidity-sensitive material deposited on the substrate gradually decreases in the direction away from the second atomizing nozzle (16). The first humidity-sensitive material and the second humidity-sensitive material each respond sensitively to different ranges of humidity change. The cavity comprises a top plate (4), a bottom porous filter (5), and a cylinder (19). The bottom porous filter is used to fix and place the substrate. A heater (10) and a thermocouple (11) are provided inside the wall of the cylinder (19). The heater (10) and the thermocouple (11) are electrically connected to a temperature controller (20) to control the temperature inside the cavity. A first atomizing pipe (12) and a second atomizing pipe (13) are symmetrically arranged on the left and right side walls of the cylinder (19). A first atomizing nozzle (15) and a second atomizing nozzle (16) are respectively provided at one end of the first atomizing pipe (12) and the second atomizing pipe (13). The first atomizing nozzle (15) points obliquely downward from above the first edge of the rectangular substrate (18) to the second edge of the rectangular substrate (18); the second atomizing nozzle (16) points obliquely downward from above the second edge of the rectangular substrate (18) to the first edge of the rectangular substrate (18). Two clamping devices (17) for fixing a rectangular substrate (18) are symmetrically arranged between the bottom porous filter (5) and the bottom end of the cylinder (19). The rectangular substrate (18) is attached to the bottom porous filter (5), and the clamping device (17) clamps the rectangular substrate (18) and makes it flat.

2. The apparatus as described in claim 1, characterized in that: The cavity is fixed in a frame; the frame includes multiple studs (1), an upper cover plate (2), a lower cover plate (3), multiple upper nuts (6), and multiple lower nuts (7) arranged symmetrically. Each stud (1) passes through the upper cover plate (2) and the lower cover plate (3). The upper nuts (6) and the lower nuts (7) are fastened to the upper and lower ends of the studs (1) respectively, so that the cavity is fixed in the space enclosed by multiple studs (1), upper cover plate (2), and lower cover plate (3) arranged symmetrically.

3. The apparatus as described in claim 1, characterized in that: The other ends of the first atomizing pipe (12) and the second atomizing pipe (13) are respectively connected to the outlet (25a) of the first jet atomizer and the outlet (25b) of the second jet atomizer. The first jet atomizer and the second jet atomizer are respectively used to hold the solutions formed by the first humidity-sensitive material and the second humidity-sensitive material being uniformly dispersed in the solvent, and to atomize and spray the solutions when needed.

4. The apparatus as described in claim 3, characterized in that: The first atomizing pipeline (12) and the second atomizing pipeline (13) are each provided with a first automatic valve and a second automatic valve. The first automatic valve and the second automatic valve are used to control the opening and closing of the first atomizing pipeline (12) and the second atomizing pipeline (13). During operation, the first automatic valve and the second automatic valve switch on and off alternately, so that the first humidity-sensitive material and the second humidity-sensitive material are pulsed atomized and sprayed out.

5. The apparatus as described in claim 4, characterized in that: The controller controls the alternating opening and closing of the first and second automatic valves.

6. The apparatus according to any one of claims 2-5, characterized in that: When the upper nut (6) and lower nut (7) are fastened to the upper and lower ends of the stud (1) respectively, a washer (9) is also provided.

7. The apparatus as claimed in claim 2, characterized in that: The lower cover plate (3) has a through hole in the middle, and an air extraction pipe (14) is provided in the through hole. The air extraction pipe is connected to a micro vacuum pump, so that the air pressure in the cavity is lower than the external atmospheric pressure when the device is working, forming an airflow, and the mist of the humidity-sensitive material is more likely to flow to the rectangular substrate (18).

8. The apparatus as claimed in claim 7, characterized in that: The air extraction pipeline is threadedly connected to the micro vacuum pump via bolts (8).

9. The apparatus according to any one of claims 1-8, characterized in that: The first jet atomizer includes an outlet (25a), a gas flow meter inlet (26a), a variable air intake (27a), a carrier gas injection orifice (28a), a siphon (29a), a liquid storage container (30a), and a filter (31a); the second jet atomizer includes an outlet (25b), a gas flow meter inlet (26b), a variable air intake (27b), a carrier gas injection orifice (28b), a siphon (29b), a liquid storage container (30b), and a filter (31b); each liquid storage container (30a, 30b) is used to hold a solution diluted with a humidity-sensitive material, the filter (31a, 31b) is used to filter out particles of humidity-sensitive material with excessive particle size in the solution, the outlet (25a, 25b) of the jet atomizer is used to spray out aerosol, the variable air intake (27a, 27b) is used to regulate the carrier gas flow rate and velocity, the gas flow meter is used to measure the gas flow rate, and the carrier gas injection orifice (28a, 28b) is used to spray the carrier gas at high speed.

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