CN113588727B - Humidity sensor chip without storage module - Google Patents

Abstract

The invention discloses a humidity sensor chip without a storage module, which comprises a humidity sensitive module, a measuring circuit module and a microprocessing unit (MCU); the humidity sensitive module comprises a humidity sensitive material, a substrate, a first electrode, a second electrode and a third electrode; the humidity sensitive material, the substrate, the first electrode, the second electrode and the third electrode form a humidity sensitive capacitor-resistor composite structure with a three-electrode structure; the first electrode, the humidity sensitive material and the second electrode form a humidity sensitive resistor (humidity sensitive resistor) structure, and the humidity sensitive material is used as the humidity sensitive material of the humidity sensitive resistor (humidity sensitive resistor); the substrate is a crystalline material with piezoelectric effect.

Description

Humidity sensor chip without memory module

This application is a divisional application for a humidity sensor chip with a three-electrode structure. The application date of this application is: 2020.01.07, the application number is 202010011995.7, and the name of the invention is: A humidity sensor chip with a three-electrode structure.

technical field

The invention relates to a humidity sensor chip without a storage module.

Background technique

The patent application of the present invention is a divisional application of CN202010011995.7, which is proposed to overcome the singularity defect of the parent case.

For the relevant background technical documents of the humidity sensor, please refer to:

[1] Hosseinbabaei, F. and P. Shabani (2014). “A gold/organic semiconductordiode for ppm-level humidity sensing.” Sensors and Actuators B-chemical 205: 143-150.

[2] Hosseini, M.S. and S. Zeinali (2019). “Capacitive humidity sensing using a metal-organic framework nanoporous thin film fabricated through electrochemical in situ growth,” Journal of Materials Science: Materials in Electronics 30(4): 3701-3710.

[3] Jeong, W., J. Song, et al. (2019). "Breathable Nanomesh Humidity Sensor for Real-time Skin Humidity Monitoring." ACS Applied Materials & Interfaces 11

(47): 44758-44763.

[4] Kuang, Q., C. Lao, et al. (2007). "High-sensitivity humidity sensor based on a single SnO2 nanowire." Journal of the American Chemical Society 129

(19): 6070-6071.

[5] Li, L., F. Vilela, et al. (2009). "Miniature humidity micro-sensor based on organic conductive polymer-poly(3,4-ethylenedioxythiophene)." Micro & NanoLetters 4(2): 84-87.

[6] Popov, V.I., D.V. Nikolaev, et al. (2017). “Graphene-based humidity sensors: the origin of alternating resistance change.” Nanotechnology 28(35): 355501.

[7] Su, P. and C. Uen (2005). "A resistive-type humidity sensor using composite films prepared from poly(2-acrylamido-2-methylpropane sulfonate) and dispersed organic silicon sol." Talanta 66(5): 1247 -1253.

[8] Zhang, C., W. Zhang, et al. (2010). "Optical fibre temperature and humidity sensor." Electronics Letters 46(9): 643-644.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a humidity sensor chip without a storage module, which can also realize self-diagnosis and replacement reminder of the humidity sensor chip. The concrete technical scheme that realizes the object of the present invention is:

A humidity sensor chip, the sensor chip includes a humidity sensitive module, the humidity sensitive module includes a humidity sensitive material, a substrate, an upper electrode and a lower electrode; the lower electrode is located on the back of the substrate material, and the humidity sensitive material is prepared on the front of the substrate , the upper electrode is located above the humidity-sensitive material; the humidity-sensitive material is characterized in that: it has the characteristic of water absorption, and absorbing the water in the ambient air causes the resistivity to change with the water content. The humidity-sensitive material is an organic material, or an inorganic material, or an organic/inorganic composite material.

In some embodiments, the sensor chip includes a humidity sensitive module, a measurement circuit module, and a microprocessing unit MCU; in some embodiments, the sensor chip includes a humidity sensitive module, a measurement circuit module, a storage module, and a microprocessing unit MCU.

In some embodiments, the humidity-sensitive module includes a humidity-sensitive material, a substrate, an upper electrode and a lower electrode; the humidity-sensitive material is: adding 5-8% by weight of cuprous oxide to phenyl benzoate , 4-7% by weight of zinc oxide, 4-8% by weight of 4-epoxypropanoloxycarbazole, the mixed solution formed after vigorous stirring at 90-110 ° C, namely:

The precursor solution of the humidity-sensitive material is: a hydrophobic oily mixed solution composed of cuprous oxide, zinc oxide, 4-epoxypropanoloxycarbazole (CAS number: 53-95-2), and phenyl benzoate ;

Preferably, the cuprous oxide is granular cuprous oxide of 1-10 μm, and the zinc oxide is rod-shaped zinc oxide of 0.5-5 μm;

Preferably, the weight part of cuprous oxide is 5-8%, the weight part of zinc oxide is 4-7%, the weight part of 4-epoxypropoxycarbazole is 3-6%, and the balance is benzene benzoate ester.

The preparation method of the humidity sensitive module is as follows:

(a) Preparation of the precursor solution of the humidity-sensitive material: adding 5-8% by weight of cuprous oxide, 4-7% by weight of zinc oxide, and 4-8% by weight of phenyl benzoate 4-propylene oxide alkoxycarbazole; the mixture is heated to 90-110°C, and vigorously stirred with a magnetic stirrer for 30-60 minutes to form a hydrophobic oily liquid mixture;

(b) Preparation of humidity-sensitive material on the front side of the substrate: spin-coating the hydrophobic oily mixed solution obtained in step (a) on the front side of the substrate at 90-110° C., and then naturally cool to room temperature;

(c) adopting evaporation process or sputtering process or radio frequency magnetron sputtering process to prepare the third electrode on the backside of the substrate;

(d) using a mask to prepare a first electrode and a second electrode on the humidity-sensitive material on the front side of the substrate by an evaporation process or a sputtering process or a radio frequency magnetron sputtering process;

Optionally, step (c) is adjusted before step (a).

In all embodiments of the present invention, the humidity-sensitive module includes a humidity-sensitive material, a substrate, a first electrode, a second electrode, and a third electrode; a humidity-sensitive material, a substrate, a first electrode, a second electrode, and a third electrode Three electrodes form a humidity-sensitive capacitor-resistor composite structure with a three-electrode structure, namely:

A humidity-sensitive resistor (humidity-sensitive resistor) is formed between the first electrode and the second electrode, a humidity-sensitive capacitor (humidity-sensitive capacitor) is formed between the first electrode and the third electrode, and a humidity is also formed between the second electrode and the third electrode. A sensitive capacitor (humidity sensitive capacitor), and the first electrode, the second electrode and the third electrode are the same humidity sensitive material;

The substrate is a crystalline material with piezoelectric effect.

In the present invention, the humidity sensor measures ambient air humidity, and the implementation is as follows:

The measurement circuit module is used to perform the following two measurement operations during measurement, and the sequence of the two measurement operations is not limited:

(1) The measurement circuit module applies an AC excitation signal with a preset frequency range to the first electrode and the third electrode of the humidity sensitive module, or the AC excitation signal is applied to the second electrode and the third electrode of the humidity sensitive module. , measure the resonant frequency of the humidity sensitive module;

(2) The measurement circuit module applies a direct current signal to the first electrode and the second electrode of the humidity sensitive module, and measures the humidity sensitive resistance (humidity sensitive resistance) value of the humidity sensitive module;

the resonant frequency and the humidity-sensitive resistance (humidity-sensitive resistance) value vary with the moisture content of the humidity-sensitive material;

The measurement circuit module transmits the measured resonant frequency and humidity sensitive resistance (humidity sensitive resistance) value of the measured humidity sensitive module to the microprocessor unit MCU;

The micro-processing unit MCU calculates and obtains two ambient air humidity reference values, namely, ambient air humidity reference value a and ambient air humidity reference value b, respectively, according to the resonant frequency and the humidity sensitive resistor (humidity sensitive resistor) value;

Preferably, the mean square value or average value of the ambient air humidity reference value a and the ambient air humidity reference value b is output as the result.

The humidity sensor chip realizes self-diagnosis and replacement reminder. Specifically: the micro-processing unit MCU includes a discriminating function module, and the discriminating function module performs the following discriminating functions: the discriminating function module in the micro-processing unit MCU obtains the ambient air humidity reference value a and the environment according to the calculation. The air humidity reference value b performs self-diagnosis to determine whether the humidity sensor chip is faulty or its performance is aging.

During the research process of the present invention, the inventor found that some humidity-sensitive modules have two different physical properties that change with the moisture content of the humidity-sensitive material. Both physical properties are closely related to the moisture content of the humidity-sensitive material. Both can be used to detect humidity in ambient air. The inventor also found that, due to two different physical properties, the physical mechanism of the change with the moisture content is different. After the moisture sensitive module is constructed, these two different physical properties are closely related to the moisture content of the moisture sensitive material. Physical properties, the performance degradation curve is also inconsistent as the humidity sensor is used for an extended period of time, i.e., different physical properties related to humidity sensitivity, the deviation in measurement accuracy will become more and more as the sensor is used for an extended period of time. is larger, and the degree of deviation is inconsistent.

In the present invention, the humidity sensitivity of the resistivity of certain humidity sensitive materials is utilized to detect ambient air humidity. At the same time , the inventor creatively proposes that the humidity-sensitive module includes a humidity-sensitive material, a substrate, a first electrode, a second electrode and a third electrode; the humidity-sensitive material, the substrate, the first electrode, the second electrode and the third electrode A humidity-sensitive capacitor-resistor composite structure that constitutes a three-electrode structure; the first electrode, the humidity-sensitive material, the substrate, and the third electrode constitute a capacitor structure , and the humidity-sensitive material and the substrate are the composite dielectric layer of the capacitor; the second electrode , The humidity-sensitive material, the substrate, and the third electrode also constitute the capacitor structure, and the humidity-sensitive material and the substrate are the dielectric layers of the capacitor ;

When an alternating current excitation signal of a certain frequency is applied to the capacitor, mechanical oscillation will occur, and the resonance frequency of the mechanical oscillation is sensitively dependent on the humidity of the ambient air. This is because the quartz flakes have piezoelectric properties. When an alternating current excitation signal of a certain frequency is applied, mechanical oscillation will occur, and the resonance frequency of the mechanical oscillation is sensitive to the cutting direction, size, and quality of the quartz flakes, while water molecules are sensitive to humidity. After the material is adsorbed, the quality of the humidity-sensitive material attached to the quartz sheet is changed, so that when the capacitor is applied with an AC excitation signal of a certain frequency, the resonant frequency is sensitive to a certain frequency.

Depends on the humidity of the ambient air.

Therefore, in the humidity sensor chip of the three-electrode structure of the present invention, when measuring the ambient air humidity, two physical characteristics of the humidity sensitive module created by the present invention are simultaneously utilized:

(I) The resonant frequency of the humidity-sensitive module changes with the moisture content of the humidity-sensitive material; (II) The humidity-sensitive resistor (humidity-sensitive resistor) value of the humidity-sensitive module changes with the change of the moisture content of the humidity-sensitive material.

In addition, these two physical mechanisms are different. With the extension of the humidity sensor's use time, the performance degradation curve is also inconsistent, which can be used to realize the self-diagnosis and replacement reminder functions of the humidity sensor.

For more detailed technical principles, please refer to the descriptions of the two prior patent applications filed by the inventor:

CN2019111875813, CN2019113061843.

The differences from the two earlier applications above are:

In the present invention, the physical properties of the humidity-sensitive resistance (humidity-sensitive resistance) value of the humidity-sensitive module changing with the moisture content of the humidity-sensitive material are used, which replaces the two previously applied patent applications (CN2019111875813, CN2019113061843). The physical properties of the capacitance value (dielectric constant) of the utilized humidity-sensitive module as a function of the moisture content of the humidity-sensitive material;

In some embodiments of the present invention, the independent storage modules existing in the two previously filed patent applications (CN2019111875813, CN 2019113061843) are cancelled, and the two different physical properties of the humidity sensitive module are no longer recorded as The standard curve of the moisture content of the humidity sensitive material changes, the value of the ambient air humidity is calculated by the microprocessor unit MCU according to the formula, so that the cost of the humidity sensor chip can be reduced;

In all embodiments of the present invention, the humidity-sensitive material, the substrate, the first electrode, the second electrode and the third electrode in the humidity-sensitive module constitute a humidity-sensitive capacitor-resistance composite structure with a three-electrode structure, and the first electrode , A humidity-sensitive resistor (humidity-sensitive resistor) is formed between the second electrodes, a humidity-sensitive capacitor (humidity-sensitive capacitor) is formed between the first electrode and the third electrode, and a humidity-sensitive capacitor (humidity-sensitive capacitor) is formed between the second electrode and the third electrode. Humidity sensitive capacitor), and the first electrode, the second electrode and the third electrode are the same humidity sensitive material; while in the two patent applications filed earlier, it is a simple upper and lower electrodes, and the humidity sensitive module The humidity-sensitive material, substrate, upper electrode, and lower electrode constitute a simple humidity-sensitive capacitor structure.

In the present invention, two organic/inorganic composite humidity-sensitive materials that are not disclosed in the previous application are further proposed, that is, the humidity-sensitive materials are: adding 5-8% by weight of cuprous oxide to phenyl benzoate, A mixture formed after vigorous stirring of 4-7% by weight of zinc oxide and 4-8% by weight of 4-epoxypropanoloxycarbazole;

In the present invention, the proposed organic/inorganic composite humidity-sensitive material is a hydrophobic humidity-sensitive material, so as to avoid peeling of the humidity-sensitive sensing layer due to dissolving in water at higher humidity under higher humidity conditions, and This technical issue was not considered in the two earlier applications;

In the present invention, as a preferred technical solution, an electronic switch controlled by the micro-processing unit MCU is arranged between the first electrode and the second electrode, and the electronic switch is a transmission gate composed of a pair of PMOS/NMOS; The control terminal is connected to the micro-processing unit MCU; when measuring the resonant frequency of the humidity sensitive module, the electronic switch is controlled by the micro-processing unit MCU to be in an on state, so that the first electrode and the second electrode are short-circuited, and the rest of the time is The aforementioned electronic switch remains in an off state, and this technical problem is not involved in the two earlier applications;

In the present invention, as a preferred technical solution, a temperature sensor is also integrated in the humidity sensitive module, the temperature sensor is connected to the measurement circuit module, and the measurement circuit module transmits the measured temperature value of the humidity sensitive material to the microprocessing unit MCU, and the microcomputer The processing unit MCU corrects the measured ambient air humidity value according to the temperature value. The inventors on page 5/9 of the invention found that temperature affects the relative humidity of a given ambient space, and this technical problem was not considered in the two prior applications. During the self-diagnosis process, the humidity sensor chip of the present invention does not need to rely on any external reference standard other than the humidity sensor chip itself, but only uses its own characteristics to realize self-diagnosis.

So far, the inventor has described the working principle, technical solutions, and technical effects of the present invention. For details, please refer to the two prior patent applications of the present inventor (CN2019111875813, CN 2019113061843). Of course, in addition to the aforementioned features, the present invention also has the beneficial effects of the above two prior patent applications.

Description of drawings

Figure 1: The front view of the humidity sensor chip, 1 is the first electrode, 2 is the second electrode, 3 is the humidity sensitive material, the quartz substrate and the third electrode on the back are not marked.

Fig. 2 is a three-dimensional schematic diagram of a humidity sensor chip. In Fig. 2, 1 is a first electrode, 2 is a second electrode, 3 is a third electrode, 4 is a humidity sensitive material, and 5 is a quartz flake.

Figure 3: A diagram of another humidity sensor chip. In Figure 3, 1 is the first electrode, 2 is the second electrode, 3 is the third electrode, and 4 is the humidity-sensitive material. In the figure, the quartz flake is below the humidity-sensitive material. , not marked.

Fig. 4: Equivalent circuit of the capacitance-resistance composite structure of the humidity sensitive module of the humidity sensor chip in Fig. 3 or Fig. 4.

Detailed ways

The technical solutions of the present invention are specifically described below with reference to examples.

Humidity sensor chip, the sensor chip includes a humidity sensitive module, a measurement circuit module, and a microprocessor unit MCU. In some embodiments, the humidity-sensitive material is an organic material; in some embodiments, the humidity-sensitive material is an inorganic material; in some embodiments, the humidity-sensitive material is an organic/inorganic composite material.

In some embodiments, relative to the prior invention patent application with application number CN2019111875813, there is no independent storage module; in such embodiments, the humidity-sensitive module includes a humidity-sensitive material, a substrate, a first electrode, a second The electrode and the third electrode; the humidity-sensitive material, the substrate, the first electrode, the second electrode and the third electrode constitute a humidity-sensitive capacitor-resistance composite structure with a three-electrode structure; as shown in FIG. 2 .

The humidity sensitive module, the micro-processing unit MCU, and the storage module are integrated on a piece of substrate material through stack packaging technology to obtain a humidity sensor chip; a humidity sensitive resistor (humidity sensitive resistor) is formed between the first electrode and the second electrode, and the first electrode, A humidity-sensitive capacitor (humidity-sensitive capacitor) is formed between the third electrodes, a humidity-sensitive capacitor (humidity-sensitive capacitor) is also formed between the second electrode and the third electrode, and the first electrode, the second electrode and the third electrode are mutually It is the same humidity sensitive material; the humidity sensitive material is prepared on the front side of the substrate, the first electrode and the second electrode are located on the top of the humidity sensitive material, and the third electrode is located on the back side of the substrate material; the first electrode and the second electrode are one pairs of electrodes surrounding each other without touching each other, with moisture-sensitive material therebetween;

The first electrode, the humidity sensitive material, the substrate and the third electrode constitute a capacitor structure, and the humidity sensitive material and the substrate are the composite dielectric layer of the capacitor; the second electrode, the humidity sensitive material, the substrate and the third electrode also constitute the capacitor structure , the humidity-sensitive material and the substrate are the dielectric layers of the capacitor; the first electrode, the humidity-sensitive material, and the second electrode constitute a humidity-sensitive resistor structure, and the humidity-sensitive material is used as the humidity-sensitive material of the humidity-sensitive resistor;

In such an embodiment, the micro-processing unit MCU calculates two ambient air humidity reference values, ie, ambient air humidity reference value a and ambient air humidity reference value b, respectively, according to the preset formula, from the resonance frequency and the humidity sensitive resistance value.

In some embodiments, the sensor chip includes a humidity sensitive module, a measurement circuit module, a micro-processing unit MCU, and a storage module; that is, compared with the foregoing embodiments, an independent storage module is added, and the storage module is used to store standard parameters library; in such an embodiment: the humidity sensitive module includes a humidity sensitive material, a substrate, a first electrode, a second electrode and a third electrode; the humidity sensitive material, the substrate, the first electrode, the second electrode and the third electrode A humidity-sensitive capacitor-resistor composite structure that constitutes a three-electrode structure; a humidity-sensitive module, a micro-processing unit MCU, a measurement circuit module, and a storage module are integrated on a piece of substrate material by stacking packaging technology to obtain a humidity sensor chip; the first electrode, A humidity-sensitive resistor is formed between the second electrodes, a humidity-sensitive capacitor is formed between the first electrode and the third electrode, a humidity-sensitive capacitor is also formed between the second electrode and the third electrode, and the first electrode, the second electrode and the third electrode The electrodes are of the same humidity sensitive material as each other; as shown in Figure 2.

The humidity-sensitive material is prepared on the front side of the substrate, the first electrode and the second electrode are located on the top of the humidity-sensitive material, and the third electrode is located on the backside of the substrate material; the first electrode and the second electrode are a pair of surrounding each other without contact The first electrode, the humidity-sensitive material, the substrate, and the third electrode constitute a capacitor structure, and the humidity-sensitive material and the substrate are the composite dielectric layer of the capacitor; the second electrode, the humidity-sensitive material , The substrate and the third electrode also constitute the capacitor structure, the humidity sensitive material and the substrate are the dielectric layers of the capacitor; the first electrode, the humidity sensitive material and the second electrode constitute a humidity sensitive resistor (humidity sensitive resistor) structure, and the humidity sensitive material Humidity sensitive material as humidity sensitive resistor;

In such an embodiment, a standard parameter library is stored in the storage module, and the resonant frequency of the humidity sensitive module and the humidity sensitive resistance value of the humidity sensitive module are recorded in the standard parameter library as the moisture content of the humidity sensitive material changes, respectively. changing standard curve;

According to the measured resonant frequency and humidity sensitive resistance value of the humidity sensitive module, the microprocessor unit MCU changes the resonant frequency and humidity sensitive resistance value of the humidity sensitive module recorded in the standard parameter library with the moisture content of the humidity sensitive material, respectively. The standard curve that changes with the change is indexed, compared and calculated respectively, and the reference value a of the ambient air humidity and the reference value b of the ambient air humidity are obtained respectively.

In all embodiments, preferably, the substrate is a crystalline material with piezoelectric effect.

In all embodiments, preferably, the first electrode and the second electrode are a pair of interdigitated electrodes, as shown in Figures 1 and 2, or a pair of spiral electrodes, as shown in Figure 3, or a pair of looped electrodes electrode;

In all embodiments, preferably, the first electrode, the second electrode and the third electrode are gold electrodes or silver electrodes;

In some embodiments, the first electrode, the second electrode, and the third electrode are all prepared by an evaporation process;

In some embodiments, the first electrode, the second electrode, and the third electrode are all prepared by a sputtering process;

In some embodiments, the first electrode, the second electrode, and the third electrode are all prepared by a radio frequency magnetron sputtering process;

In all embodiments, preferably, the humidity-sensitive material is a hydrophobic material to avoid peeling of the humidity-sensitive sensing layer due to dissolving in water at higher humidity under higher humidity conditions;

As an example, the precursor solution of the humidity-sensitive material is: a solution consisting of cuprous oxide, zinc oxide, 4-epoxypropoxycarbazole (CAS number: 53-95-2), phenyl benzoate Hydrophobic oily mixture;

Preferably, the cuprous oxide is granular cuprous oxide of 1-10 μm, and the zinc oxide is rod-shaped zinc oxide of 0.5-5 μm;

Preferably, the weight part of cuprous oxide is 5-8%, the weight part of zinc oxide is 4-7%, the weight part of 4-epoxypropoxycarbazole is 3-6%, and the balance is benzene benzoate ester.

Here, the hydrophobicity of phenyl benzoate and 4-epoxypropanoloxycarbazole is utilized. Cuprous oxide and zinc oxide are used as moisture sensitive materials.

The preparation method of the humidity sensitive module is as follows:

(a) Preparation of the precursor solution of the humidity-sensitive material: adding 5-8% by weight of cuprous oxide, 4-7% by weight of zinc oxide, and 4-8% by weight of phenyl benzoate 4-propylene oxide alkoxycarbazole; the mixture is heated to 90-110°C, and vigorously stirred with a magnetic stirrer for 30-60 minutes to form a hydrophobic oily liquid mixture;

(b) Preparation of humidity-sensitive material on the front side of the substrate: spin-coating the hydrophobic oily mixed solution obtained in step (a) on the front side of the substrate at 90-110° C., and then naturally cool to room temperature;

(c) adopting evaporation process or sputtering process or radio frequency magnetron sputtering process to prepare the third electrode on the backside of the substrate;

(d) using a mask to prepare a first electrode and a second electrode on the humidity-sensitive material on the front side of the substrate by an evaporation process or a sputtering process or a radio frequency magnetron sputtering process;

Optionally, step (c) is adjusted before step (a).

The humidity-sensitive module includes a humidity-sensitive material, a substrate, an upper electrode and a lower electrode; the humidity-sensitive material is: adding 5-8% by weight of cuprous oxide to phenyl benzoate, and 4-8% by weight of cuprous oxide. 7% of zinc oxide, 4-8% by weight of 4-epoxypropanoloxycarbazole, and a mixture formed after vigorous stirring at 90-110°C.

In all embodiments, preferably, an electronic switch controlled by a microprocessor unit MCU is arranged between the first electrode and the second electrode. When measuring the resonant frequency of the humidity sensitive module, the electronic switch is controlled by the microprocessor. The unit MCU is controlled to be in an on state, so that the first electrode and the second electrode are short-circuited and connected, and the electronic switch is kept in an off state during the rest of the time; preferably, the electronic switch is a transmission gate composed of a pair of PMOS/NMOS; The control terminal of the door is connected to the microprocessor unit MCU.

As shown in Figure 4, K is an electronic switch, which is controlled by the MCU; the first electrode 1, the humidity-sensitive material 4, the quartz sheet 5, and the third electrode 3 form a capacitor structure C1; the second electrode 2, the humidity-sensitive material 4, The quartz sheet 5 and the third electrode 3 constitute the capacitor structure C2; the first electrode 1, the humidity sensitive material 4, and the second electrode 2 constitute the humidity sensitive resistor R.

In all embodiments, preferably, a temperature sensor is further integrated in the humidity sensitive module, the temperature sensor is connected to the measurement circuit module, and the measurement circuit module transmits the measured temperature value of the humidity sensitive material to the microprocessor unit MCU, and the microprocessor processes The unit MCU corrects the measured ambient air humidity value according to the temperature value. The correction of the humidity measurement value by using temperature can be performed through an empirical formula, and those skilled in the art are capable of realizing it according to the description of the present invention, which will not be repeated here.

In all embodiments, the measurement circuit module is configured to perform the following two measurement operations during measurement, and the sequence of the two measurement operations is not limited:

(1) The measurement circuit module applies an AC excitation signal with a preset frequency range and a frequency change to the first electrode and the third electrode of the humidity sensitive module to measure the resonant frequency of the humidity sensitive module; as shown in Figure 4, the AC excitation signal Added between points A and G, the electronic switch K is in an open state; or,

The measurement circuit module applies an AC excitation signal with a preset frequency range and a frequency change to the second electrode and the third electrode of the humidity sensitive module to measure the resonant frequency of the humidity sensitive module; as shown in Figure 4, that is, the AC excitation signal is added to B Between the two points of G and G, the electronic switch K is in an off state;

Or, preferably, the electronic switch is controlled by the micro-processing unit MCU to be in an on state, so that the first electrode and the two electrodes on page 8/9 are short-circuited, and the measurement circuit module is connected to the first electrode and the second electrode of the humidity sensitive module. Apply an AC excitation signal with a preset frequency range and a frequency change to the third electrode to measure the resonant frequency of the humidity sensitive module; as shown in Figure 4, the equivalent circuit of the humidity sensitive module on the left becomes the simple capacitor on the right Form C, that is, the electronic switch K is in a conducting state, the AC excitation signal is equivalent to being added between points A and G, and C is equivalent to the equivalent capacitance of C1 and C2 in parallel.

(2) The electronic switch is controlled by the micro-processing unit MCU to be in an off state, so that the first electrode and the second electrode are disconnected, and the measurement circuit module applies a direct current signal to the first electrode and the second electrode of the humidity sensitive module to measure Humidity sensitive resistance (humidity sensitive resistance) value of the humidity sensitive module; at this time, C1 and C2 are equivalent to circuit breakage, and do not have any influence on the measurement of the humidity sensitive resistance (humidity sensitive resistance) value.

The resonant frequency and the humidity-sensitive resistance value vary with the moisture content of the humidity-sensitive material;

The measurement circuit module transmits the measured resonant frequency and humidity sensitive resistance (humidity sensitive resistance) value of the measured humidity sensitive module to the microprocessor unit MCU;

The microprocessor unit MCU calculates and obtains two ambient air humidity reference values respectively according to the resonance frequency and the humidity sensitive resistance value, namely the ambient air humidity reference value a and the ambient air humidity reference value b;

Preferably, the mean square value or average value of the ambient air humidity reference value a and the ambient air humidity reference value b is output as the result. For specific calculation details, please refer to two prior patent applications (CN2019111875813, CN2019113061843) of the inventor.

In some embodiments, the humidity sensor chip is also capable of self-diagnosis and replacement reminders, specifically:

The micro-processing unit MCU includes a discrimination function module, and the discrimination function module performs the following discrimination functions:

The discrimination function module in the micro-processing unit MCU performs self-diagnosis according to the ambient air humidity reference value a and ambient air humidity reference value b obtained by calculation, and determines whether the humidity sensor chip is faulty or has performance aging. The specific implementation is as follows:

Preset the first discrimination threshold, calculate the absolute value of the difference between the aforementioned ambient air humidity reference value a and the ambient air humidity reference value b; determine whether the absolute value of the difference between the ambient air humidity reference value a and the ambient air humidity reference value b is greater than the predetermined value. The set first judgment threshold; if the absolute value of the difference is less than the preset first judgment threshold, then: the root mean square value or average value of the ambient air humidity reference value a and the ambient air humidity reference value b is output as the result, And it means that the humidity sensor chip is working normally;

If the absolute value of the difference is equal to or greater than the preset first discrimination threshold, then: the micro-processing unit MCU further outputs a warning message, the warning message indicates that the humidity sensor chip is faulty, or the performance is aging, indicating that maintenance or replacement is required;

Preferably, the discrimination function module in the micro-processing unit MCU is further preset with a second discrimination threshold, and the second discrimination threshold is greater than the first discrimination threshold; if the absolute value of the difference is smaller than the preset first discrimination threshold , then: the root mean square value or average value of the ambient air humidity reference value a and the ambient air humidity reference value b is output as the result, and it indicates that the humidity sensor chip is working normally; if the absolute value of the difference is equal to or greater than the preset first The first judgment threshold is smaller than the second judgment threshold, then: the microprocessor unit MCU outputs a warning message, and the warning message indicates that the humidity sensor chip may be faulty, or the performance has been slightly aged, and it is recommended to repair or replace it;

If the absolute value of the difference is equal to or greater than the preset second discrimination threshold, the micro-processing unit MCU outputs an error message indicating that the humidity sensor chip is faulty, or the performance has deteriorated seriously and must be repaired or replaced.

As an example, the preset first judgment threshold is 1%RH, and the second judgment threshold is 2%RH; in a certain measurement page 9/9, the microprocessor unit MCU changes the moisture content according to the physical property A of the humidity sensitive module The ambient air humidity reference value a calculated by the standard curve that changes with the change is 23.27%RH, and the ambient air humidity reference value b calculated according to the standard curve of the physical property B of the humidity sensitive module that changes with the change of the moisture content is 24.11%RH, then, the absolute value of the difference between the ambient air humidity reference value a and the ambient air humidity reference value b is 24.11%RH-23.27%RH=0.84%RH,

The discrimination function module in the micro-processing unit MCU is compared, and it is concluded that the absolute value of the difference 0.84%RH is less than the preset first discrimination threshold 1%RH. Therefore, it means that the humidity sensor chip is working normally, and the average output of a and b is The root value of 23.69%RH is used as the final result to output the ambient air humidity value.

As an example, the preset first discrimination threshold is 1%RH, and the second discrimination threshold is 2%RH; in a certain measurement, the micro-processing unit MCU changes according to the physical property A of the humidity sensitive module as the moisture content changes. The ambient air humidity calculated from the standard curve is 42.69%RH, and the ambient air humidity calculated according to the standard curve that the physical property B of the humidity sensitive module changes with the moisture content is 44.57%RH, then, the ambient air humidity reference The absolute value of the difference between the value a and the reference value b of the ambient air humidity is 44.57%RH-42.69%RH=1.88%RH. After comparing the discriminant function module in the micro-processing unit MCU, it is concluded that the absolute value of the difference 1.88%RH is greater than The preset first judgment threshold is 1%RH, but it is less than the second judgment threshold 2%RH. Therefore, the micro-processing unit MCU outputs a warning message. The warning message indicates that the humidity sensor chip may be faulty, or the performance has been slightly aged, and maintenance is recommended. or replace.

As another example, the preset first discrimination threshold is 0.5% RH, and the second discrimination threshold is 1% RH; in a certain measurement, the micro-processing unit MCU changes with the moisture content according to the physical property A of the humidity sensitive module The ambient air humidity calculated according to the standard curve is 42.69%RH, and the ambient air humidity calculated according to the standard curve of the physical property B of the humidity sensitive module changing with the moisture content is 44.57%RH, then, the ambient air humidity The absolute value of the difference between the reference value a and the ambient air humidity reference value b is 44.57%RH-42.69%RH=1.88%RH. After comparing the discriminant function module in the micro-processing unit MCU, it is obtained: the absolute value of the difference is 1.88%RH It is greater than the preset second discrimination threshold 1%RH. Therefore, the micro-processing unit MCU outputs an error message, which indicates that the humidity sensor chip is faulty, or the performance has deteriorated seriously and must be repaired or replaced.

It can be seen from the above three examples that whether the micro-processing unit MCU outputs warning information or error information, or prompts normal operation and outputs the final calculation result, depends on the preset first and second judgment thresholds.

The setting of the first judgment threshold and the second judgment threshold depends on the tolerance of the end user to the performance degradation of the humidity sensor chip. If the end user has a low tolerance for the performance degradation of the humidity sensor chip and there is a need for accurate measurement, a smaller first and second judgment thresholds can be preset; If the tolerance is high, and no particularly precise measurement requirements are required, relatively large first discrimination thresholds and second discrimination thresholds may be preset. On the other hand, the preset size of the first discrimination threshold and the second discrimination threshold will also affect the in-service time of the humidity sensor chip. If the preset first judgment threshold and the second judgment threshold are smaller, the in-service time of the humidity sensor chip will be shorter; if the preset first and second judgment thresholds are larger, the in-service time of the humidity sensor chip will be sufficient. longer. It all depends on the end customer's requirements for measurement accuracy and cost of use.

In each embodiment described in the specification, the adopted technical means are not in conflict with each other, that is, they can be freely combined to form different technical solutions. The technical solutions obtained by these possible permutations and combinations are deemed to have been recorded in the original application documents of the present application. Unless a special statement is made, some technical means are technically contradictory and cannot coexist in the same technical solution. The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Substitutions should be covered within the protection scope of the present invention.

Claims (15)

1. a humidity sensor chip without a storage module, characterized in that: The sensor chip includes a humidity sensitive module, a measurement circuit module, and a microprocessor unit MCU; it does not contain an independent storage module; The humidity-sensitive module includes a humidity-sensitive material, a substrate, a first electrode, a second electrode, and a third electrode; the humidity-sensitive material, the substrate, the first electrode, the second electrode, and the third electrode form a humidity-sensitive capacitor with a three-electrode structure - Resistive composite structure; A humidity-sensitive resistor is formed between the first electrode and the second electrode, a humidity-sensitive capacitor is formed between the first electrode and the third electrode, a humidity-sensitive capacitor is also formed between the second electrode and the third electrode, and the first electrode and the second electrode are also formed. The electrode and the third electrode are the same humidity sensitive material; The humidity sensitive material is prepared on the front side of the substrate, the first electrode and the second electrode are both located on the top of the humidity sensitive material, and the third electrode is located on the back side of the substrate material; The first electrode, the humidity sensitive material, the substrate and the third electrode constitute a capacitor structure, and the humidity sensitive material and the substrate are the composite dielectric layer of the capacitor; the second electrode, the humidity sensitive material, the substrate and the third electrode also constitute the capacitor structure , the humidity-sensitive material and the substrate are the dielectric layers of the capacitor; the first electrode, the humidity-sensitive material, and the second electrode form a humidity-sensitive resistor structure, and the humidity-sensitive material is used as the humidity-sensitive material of the humidity-sensitive resistor; the substrate is a humidity-sensitive material with piezoelectric effect crystalline material; An electronic switch controlled by the micro-processing unit MCU is arranged between the first electrode and the second electrode. When measuring the resonant frequency of the humidity sensitive module, the electronic switch is controlled by the micro-processing unit MCU to be in a conducting state, so that the first electrode and the second electrode are in a conducting state. The two electrodes are short-circuited, and the electronic switch remains disconnected for the rest of the time. 2. The humidity sensor chip according to claim 1, wherein: The moisture sensitive material is a hydrophobic material. 3. The humidity sensor chip of claim 1, wherein: The first electrode and the second electrode are a pair of double electrodes that surround each other without contact, and have humidity-sensitive material in between; the first electrode and the second electrode are a pair of interdigitated electrodes, or a pair of spiral electrodes, or a pair of Circular electrode. 4. The humidity sensor chip of claim 1, wherein: The first electrode, the second electrode and the third electrode are gold electrodes or silver electrodes. 5 . The humidity sensor chip according to claim 4 , wherein the first electrode, the second electrode and the third electrode are all prepared by an evaporation process or a sputtering process. 6 . 6. The humidity sensor chip according to claim 1, wherein the humidity sensitive material is an organic material, an inorganic material, or an organic/inorganic composite material. 7. The humidity sensor chip of claim 1, wherein the substrate is a quartz flake. 8 . The humidity sensor chip according to claim 1 , wherein the electronic switch is a transmission gate composed of a pair of PMOS/NMOS; the control end of the transmission gate is connected to the micro-processing unit MCU. 9 . 9. The humidity sensor chip according to any one of claims 1-4, wherein: A temperature sensor is also integrated in the humidity sensitive module. The temperature sensor is connected to the measurement circuit module. The measurement circuit module transmits the measured temperature value of the humidity sensitive material to the micro-processing unit MCU. The air humidity value is corrected. 10. The humidity sensor chip according to any one of claims 1-4, wherein: The measurement circuit module is used to perform the following two measurement operations during measurement, and the sequence of the two measurement operations is not limited: (1) The measurement circuit module applies an AC excitation signal of a preset frequency range and a frequency change to the first electrode and the third electrode of the humidity sensitive module to measure the resonant frequency of the humidity sensitive module; or, The measurement circuit module applies an AC excitation signal with a preset frequency range and a frequency change to the second electrode and the third electrode of the humidity sensitive module, and measures the resonance frequency of the humidity sensitive module; (2) The electronic switch is controlled by the micro-processing unit MCU to be in a disconnected state, so that the first electrode and the second electrode are disconnected, and the measurement circuit module applies a direct current signal to the first electrode and the second electrode of the humidity sensitive module to measure the humidity sensitive module. The humidity sensitive resistance value of the module; The resonance frequency and the humidity sensitive resistance value change with the moisture content of the humidity sensitive material; The measurement circuit module transmits the measured resonance frequency and humidity sensitive resistance value of the measured humidity sensitive module to the microprocessor unit MCU; The microprocessor unit MCU calculates and obtains two ambient air humidity reference values, namely, ambient air humidity reference value a and ambient air humidity reference value b, respectively, according to the resonant frequency and the humidity sensitive resistance value. 11. The humidity sensor chip according to claim 10, wherein: The electronic switch is controlled by the micro-processing unit MCU to be in an on state, so that the first electrode and the second electrode are short-circuited, and the measurement circuit module applies a predetermined frequency range, Frequency-varying AC excitation signal to measure the resonant frequency of the humidity-sensitive module. 12 . The humidity sensor chip according to claim 11 , wherein the mean square value or average value of the ambient air humidity reference value a and the ambient air humidity reference value b is output as the result. 13 . 13. The humidity sensor chip of claim 10, wherein: The micro-processing unit MCU calculates two ambient air humidity reference values, ie, ambient air humidity reference value a and ambient air humidity reference value b, respectively, by calculating the resonant frequency and the humidity-sensitive resistance value according to the preset formula. 14. The humidity sensor chip according to claim 10, characterized in that: the humidity sensor chip self-diagnoses and reminds of replacement, specifically: the micro-processing unit MCU comprises a judging function module, and the judging function module performs the following judging function: The discrimination function module in the micro-processing unit MCU performs self-diagnosis according to the ambient air humidity reference value a and ambient air humidity reference value b obtained by calculation, and determines whether the humidity sensor chip is faulty or has performance aging, which is specifically implemented as follows: preset first discrimination Threshold, calculate the absolute value of the difference between the aforementioned ambient air humidity reference value a and ambient air humidity reference value b; Determine whether the absolute value of the difference between the ambient air humidity reference value a and the ambient air humidity reference value b is greater than the preset first determination threshold; if the absolute value of the difference is smaller than the preset first determination threshold, then: The root mean square value or average value of the ambient air humidity reference value a and the ambient air humidity reference value b is output as the result, and it indicates that the humidity sensor chip works normally; If the absolute value of the difference is equal to or greater than the preset first discrimination threshold, then: The microprocessor unit MCU further outputs a warning message, which indicates that the humidity sensor chip is faulty, or its performance is aging, indicating that it needs to be repaired or replaced. 15. The humidity sensor chip according to claim 14, wherein the discrimination function module in the micro-processing unit MCU is further preset with a second discrimination threshold, and the second discrimination threshold is greater than the first discrimination threshold; If the absolute value of the difference is less than the preset first discrimination threshold, then: The root mean square value or average value of the ambient air humidity reference value a and the ambient air humidity reference value b is output as the result, and it indicates that the humidity sensor chip works normally; If the absolute value of the difference is equal to or greater than the preset first judgment threshold and less than the second judgment threshold, then: The microprocessor unit MCU outputs a warning message, which indicates that the humidity sensor chip may be faulty, or the performance has been slightly aged, and it is recommended to repair or replace it; If the absolute value of the difference is equal to or greater than the preset second discrimination threshold, then: The micro-processing unit MCU outputs an error message, which indicates that the humidity sensor chip is faulty, or the performance has been seriously aged, and must be repaired or replaced.

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