Sensitivity test method and calibration method of pressure sensor

Abstract

The embodiment of the invention discloses a sensitivity test method and calibration method of a pressure sensor, and the test method comprises the steps: obtaining the output values Pd1, Pd2... Pdn of a to-be-tested pressure sensor in different states and the output values Pr1, Pr2... Prn of a reference pressure sensor, and n is an integer not less than 2; calculating the precision Pa of the to-be-tested pressure sensor, wherein Pa is equal to the difference between the output value Pd of the to-be-tested pressure sensor and the output value Pr of the reference pressure sensor; acquiring acceleration a1, a2... an acting on a sensing chip of the to-be-tested pressure sensor in different states; the sensitivity Ps of the pressure sensor to be measured is calculated, Ps is equal to the ratio of delta Pa to delta a, delta Pa is the variable quantity of the precision Pa or the precision Pa, and delta a is the variable quantity of the corresponding acceleration a or the corresponding acceleration a.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure sensors, and more specifically, to a sensitivity testing method and a calibration method of a pressure sensor. Background Art

[0002] In the era of rapid development of modern science and technology, air pressure sensors, as an important environmental sensing component, have been widely used in various consumer electronic terminal products, especially in the field of smart wearable devices, such as smart sports watches, health monitoring bracelets, etc. These devices not only require high accuracy and stability, but also need to adapt to a variety of complex usage environments, including underwater activities, high-intensity sports, and sweat or chemical contact during daily wear. Therefore, waterproof barometers came into being.

[0003] The waterproof barometer uses gel-coating technology to completely wrap the sensor chip and its connected gold wires in a layer of protective gel. This gel material has excellent waterproof, sweat-proof and chemical corrosion resistance, and can effectively resist the erosion of common liquids such as seawater, sweat, chlorine water, soapy water, etc., thereby significantly improving the reliability and service life of the sensor.

[0004] However, while the gel cover provides excellent environmental protection for the pressure sensor, it also introduces a new challenge. Since the gel itself has a certain weight, when it is in direct contact with the sensor's sensing chip, this additional weight will directly act on the sensitive membrane area on the chip and cause the magnitude and direction of the force acting on the sensitive membrane to change, thereby causing the pressure output value to shift. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a new technical solution for a sensitivity testing method and a calibration method of a pressure sensor.

[0006] According to one aspect of the present invention, a sensitivity testing method of a pressure sensor is provided. The pressure sensor has a sensing chip.

[0007] The sensitivity testing method of the pressure sensor includes:

[0008] Obtain output values ​​Pd1, Pd2, ..., Pdn of the pressure sensor to be tested in different states and output values ​​Pr1, Pr2, ..., Prn of the reference pressure sensor, where n is an integer not less than 2;

[0009] Calculating the accuracy Pa of the pressure sensor to be tested, where Pa is equal to the difference between the output value Pd of the pressure sensor to be tested and the output value Pr of the reference pressure sensor;

[0010] Acquire accelerations a1, a2, ..., an acting on the sensing chip of the pressure sensor to be tested in different states;

[0011] The sensitivity Ps of the pressure sensor to be tested is calculated, where Ps is equal to the ratio of ΔPa to Δa, wherein ΔPa is the change in accuracy Pa or the accuracy Pa, and Δa is the change in the corresponding acceleration a or the corresponding acceleration a.

[0012] Optionally, ΔPa is the change of the accuracy Pa, Δa is the corresponding change of the acceleration a, and n is in the range of 2 to 5;

[0013] The calculating the accuracy Pa of the pressure sensor to be tested includes: Pa is equal to the difference between the output value Pd of the pressure sensor to be tested and the corresponding output value Pr of the reference pressure sensor;

[0014] The calculating the sensitivity Ps of the pressure sensor to be tested includes: calculating a plurality of sensitivities Ps1, Ps2, ..., Psm of the pressure sensor to be tested, and taking an average value, wherein m=n-1.

[0015] Optionally, n is 2, the pressure sensor to be tested includes a first state and a second state, and the pressure sensor to be tested can be switched between the first state and the second state by rotating the pressure sensor to be tested, wherein the range of the rotation angle is 30° to 180°.

[0016] Optionally, by flipping the pressure sensor to be tested so that the pressure sensor to be tested can switch between a first state and a second state, the acceleration acting on the sensing chip of the pressure sensor to be tested in the first state is equal in magnitude and opposite in direction to the acceleration acting on the sensing chip of the pressure sensor to be tested in the second state.

[0017] Optionally, it also includes:

[0018] The pressure sensor to be tested and the reference pressure sensor are placed on a turntable, and the pressure sensor to be tested is perpendicular to the centrifugal acceleration direction of the turntable, and the reference pressure sensor is parallel to the centrifugal acceleration direction of the turntable. The centrifugal acceleration of the turntable is adjusted so that the pressure sensor to be tested and the reference pressure sensor can be in different states.

[0019] Optionally, the centrifugal acceleration direction of the turntable is horizontal, and the sensing chip of the pressure sensor to be tested is in a vertical direction.

[0020] Optionally, it also includes:

[0021] The pressure sensor to be tested and the reference pressure sensor are placed on a vibration table, and the pressure sensor to be tested is perpendicular to the vibration direction of the vibration table, and the reference pressure sensor is parallel to the vibration direction of the vibration table. During the vibration of the vibration table, the pressure sensor to be tested and the reference pressure sensor are in different states.

[0022] Optionally, the calculating the accuracy Pa of the pressure sensor to be tested includes:

[0023] Pa is equal to the difference between the effective value of the output value Pd of the pressure sensor to be tested and the effective value of the output value Pr of the reference pressure sensor;

[0024] After acquiring the accelerations a1, a2, ..., an acting on the sensing chip of the pressure sensor to be tested in different states, the method further includes:

[0025] The effective value of the acceleration a acting on the sensing chip of the pressure sensor to be tested is calculated.

[0026] Optionally, before calculating the accuracy Pa of the pressure sensor to be tested, the method further includes:

[0027] Performing filtering processing on the obtained output value Pd of the pressure sensor to be tested and the output value Pr of the reference pressure sensor;

[0028] Before calculating the effective value of the acceleration a acting on the sensing chip of the pressure sensor to be tested, the method further includes:

[0029] The acquired acceleration a acting on the sensing chip of the pressure sensor to be tested is filtered.

[0030] Optionally, ΔPa is the accuracy Pa, Δa is the corresponding acceleration a, and the calculation of the sensitivity Ps of the pressure sensor to be tested includes:

[0031] Ps is equal to the ratio of the accuracy Pa to the effective value of acceleration a.

[0032] Optionally, the sensing chip of the pressure sensor to be tested and the sensing chip of the reference pressure sensor are at the same height.

[0033] According to another aspect of the present invention, a sensitivity calibration method for a pressure sensor is provided, comprising:

[0034] Obtaining an initial sensitivity Psr of the pressure sensor at an initial position, wherein the initial sensitivity Psr is measured using the sensitivity testing method of the pressure sensor;

[0035] Obtaining a rotation angle θ of the pressure sensor relative to an initial position;

[0036] The current sensitivity Psc of the pressure sensor is calculated, where Psc is equal to the product of Psr and cosθ.

[0037] According to another aspect of the present invention, a method for calibrating the sensitivity of a pressure sensor is provided, comprising:

[0038] Place the pressure sensor vertically so that the sensing chip of the pressure sensor is in a vertical direction, and obtain the output value Pdr of the pressure sensor at this time;

[0039] Place the pressure sensor horizontally in a first direction, and obtain an output value Pd1 of the pressure sensor at this time;

[0040] Place the pressure sensor horizontally in a direction opposite to the first direction, and obtain an output value Pd2 of the pressure sensor at this time;

[0041] Calculate the accuracy Pa1 and Pa2 of the pressure sensor respectively, Pa1 is equal to the difference between the output value Pd1 of the pressure sensor and the output value Pdr of the pressure sensor, Pa2 is equal to the difference between the output value Pd2 of the pressure sensor and the output value Pdr of the pressure sensor;

[0042] The sensitivity Ps of the pressure sensor is calculated, where Ps is equal to the ratio of the change in the accuracy Pa to the corresponding change in the acceleration a.

[0043] One technical effect of the embodiments of the present disclosure is:

[0044] The sensitivity test method of the pressure sensor includes obtaining the output values ​​Pd1, Pd2...Pdn of the pressure sensor to be tested and the output values ​​Pr1, Pr2...Prn of the reference pressure sensor in different states, wherein n is an integer not less than 2; calculating the accuracy Pa of the pressure sensor to be tested, wherein Pa is equal to the difference between the output value Pd of the pressure sensor to be tested and the output value Pr of the reference pressure sensor; obtaining the accelerations a1, a2...an of the sensing chip acting on the pressure sensor to be tested in different states; calculating the sensitivity Ps of the pressure sensor to be tested, wherein Ps is equal to the ratio of ΔPa to Δa, wherein ΔPa is the change in accuracy Pa or the accuracy Pa, and Δa is the change in the corresponding acceleration a or the corresponding acceleration a. Thus, by the above-mentioned measurement method, the reference pressure sensor is used as a reference, and the sensitivity of the pressure sensor to be tested can be obtained by comparing the output value with that of the pressure sensor to be tested under the same test environment, which is convenient for evaluating the sensing accuracy and response capability of the pressure sensor to be tested, and is also convenient for compensating for the weight influence of the waterproof gel or other structures on the sensing chip, thereby improving the sensing accuracy of the pressure sensor to be tested.

[0045] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0047] Figure 1 is a flow chart of a sensitivity testing method of a pressure sensor according to an embodiment of the present disclosure;

[0048] Figure 2 This is one of the sensitivity test schematic diagrams of the first pressure sensor according to the embodiment of the present disclosure;

[0049] Figure 3 This is the second sensitivity test schematic diagram of the first pressure sensor according to the embodiment of the present disclosure;

[0050] Figure 4 is a schematic diagram of a sensitivity test of a second pressure sensor according to an embodiment of the present disclosure;

[0051] Figure 5 is a schematic diagram of sensitivity testing of a third pressure sensor according to an embodiment of the present disclosure;

[0052] Figure 6 is one of the sensitivity calibration schematic diagrams of the first pressure sensor according to the embodiment of the present disclosure;

[0053] Figure 7 This is the second sensitivity calibration diagram of the first pressure sensor according to the embodiment of the present disclosure;

[0054] Figure 8 is one of the sensitivity calibration schematic diagrams of the second pressure sensor according to the embodiment of the present disclosure;

[0055] Fig. 9 This is the second sensitivity calibration schematic diagram of the second pressure sensor according to the embodiment of the present disclosure;

[0056] Fig.10 This is the third sensitivity calibration diagram of the second pressure sensor of the embodiment of the present disclosure.

[0057] Description of reference numerals:

[0058] 1. Pressure sensor to be tested; 2. Reference pressure sensor; 3. Flip table; 4. Turntable; 5. Vibration table; 6. Angle sensor. DETAILED DESCRIPTION

[0059] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0060] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0061] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0062] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0063] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0064] An embodiment of the present invention provides a sensitivity testing method for a pressure sensor. The pressure sensor has a sensing chip. The sensing chip can sense the pressure acting on the pressure sensor and convert it into an electrical signal for output.

[0065] In order to improve the waterproof performance of the pressure sensor, a waterproof gel is usually covered on the sensing chip, and the gravity of the waterproof gel will also act on the sensing chip, causing the output value of the pressure sensor to be offset.

[0066] Alternatively, after the pressure sensor is used for a long time, there is a risk of foreign matter such as dust adhering to the sensing chip or waterproof gel inside the pressure sensor, and these foreign matter may also act on the sensing chip, causing the output value of the pressure sensor to be offset.

[0067] Based on this, it is necessary to test and calibrate the sensitivity Ps of the pressure sensor to ensure the sensing accuracy and sensing reliability of the pressure sensor.

[0068] like Figure 1 As shown, the sensitivity testing method of the pressure sensor provided by the embodiment of the present invention includes:

[0069] S1. Obtain the output values ​​Pd1, Pd2 ... Pdn of the pressure sensor 1 to be tested and the output values ​​Pr1, Pr2 ... Prn of the reference pressure sensor 2 in different states, where n is an integer not less than 2;

[0070] The pressure sensor to be tested 1 is a pressure sensor containing waterproof gel, and the reference pressure sensor 2 is a pressure sensor without waterproof gel, so that the influence of waterproof gel on the sensitivity of the pressure sensor can be evaluated by the test method. When the pressure sensor is used to make a barometer, the influence of waterproof gel on the gravity sensitivity of the pressure sensor can be evaluated by the test method, so as to compensate for the influence and ensure the measurement accuracy of the air pressure piece.

[0071] During the test, the sensing chip of the pressure sensor 1 to be tested and the sensing chip of the reference pressure sensor 2 need to be kept at the same height so that their sensing capabilities of the external pressure remain consistent.

[0072] Among them, different states can be achieved by constructing a test environment with adjustable acceleration, such as using a centrifuge, an inclined platform or a gravity simulator, so that the acceleration acting on the sensing chip of the pressure sensor 1 to be tested can be changed. Among them, according to the actual test requirements, n can be taken as any integer from 2, 3, 4, 5...10. The environmental conditions such as temperature and humidity can be kept consistent during each test to eliminate the interference of environmental factors.

[0073] S2. Calculate the accuracy Pa of the pressure sensor 1 to be tested, where Pa is equal to the difference between the output value Pd of the pressure sensor 1 to be tested and the output value Pr of the reference pressure sensor 2;

[0074] When the output values ​​of the pressure sensor 1 to be tested are obtained as Pd1 and Pd2, and the corresponding output values ​​of the reference pressure sensor 2 are obtained as Pr1 and Pr2, Pa1 = Pd1 - Pr1 and Pa2 = Pd2 - Pr2 are calculated respectively.

[0075] When the output values ​​of the pressure sensor 1 to be tested are obtained as Pd1, Pd2 and Pd3, and the corresponding output values ​​of the reference pressure sensor 2 are obtained as Pr1, Pr2 and Pr3, Pa1=Pd1-Pr1, Pa2=Pd2-Pr2, Pa3=Pd3-Pr3 are calculated respectively.

[0076] When the output value of the pressure sensor 1 to be tested is obtained as the AC Pd1, Pd2...Pdn, and the output value of the reference pressure sensor 2 is obtained as the AC Pr1, Pr2...Prn, the effective value of the output value Pd of the pressure sensor 1 to be tested and the effective value of the output value Pr of the reference pressure sensor 2 can be calculated first, and then Pa=effective value of Pd-effective value of Pr can be calculated.

[0077] S3. Obtaining the accelerations a1, a2, ... an acting on the sensing chip of the pressure sensor 1 under test in different states;

[0078] The acceleration sensor may be used to measure the acceleration a acting on the sensing chip of the pressure sensor 1 to be tested, and the direction of the sensitive axis of the acceleration sensor is consistent with the direction of the acceleration a acting on the sensing chip of the pressure sensor 1 to be tested.

[0079] S4. Calculate the sensitivity Ps of the pressure sensor 1 to be tested, where Ps is equal to the ratio of ΔPa to Δa, wherein ΔPa is the change in accuracy Pa or the accuracy Pa, and Δa is the change in the corresponding acceleration a or the corresponding acceleration a.

[0080] Among them, two or more different acceleration states can be selected, ΔPa and Δa can be calculated, and then the sensitivity Ps can be calculated using the following formula:

[0081] Ps=ΔPa / Δa, where ΔPa is the change in accuracy Pa or the accuracy Pa, and Δa is the change in acceleration a or the acceleration a.

[0082] When more than two acceleration states are used for testing, that is, when n is greater than 2, multiple groups of ΔPa / Δa can be calculated separately, and then the average value is taken as the final sensitivity value.

[0083] According to the calculated sensitivity Ps value, the response characteristics of the pressure sensor 1 under different acceleration conditions can be analyzed. If the Ps value is small and stable, it means that the pressure sensor 1 under test is less sensitive to pressure changes and is suitable for use in environments with large gravity changes; on the contrary, if the Ps value is large or fluctuates significantly, it means that the pressure sensor 1 under test is more sensitive to pressure changes and it may be necessary to further optimize the design of the pressure sensor 1 under test or perform a calibration process.

[0084] In this way, through the above-mentioned measurement method, the reference pressure sensor 2 is used as a benchmark, and by comparing the output value with that of the pressure sensor 1 to be tested under the same test environment, the sensitivity of the pressure sensor 1 to be tested can be obtained, which is convenient for evaluating the sensing accuracy and response capability of the pressure sensor 1 to be tested, and is also convenient for compensating for the weight influence of the waterproof gel or other structures on the sensing chip, thereby improving the sensing accuracy of the pressure sensor 1 to be tested.

[0085] Optionally, ΔPa is the change of the accuracy Pa, Δa is the corresponding change of the acceleration a, and n is in the range of 2 to 5;

[0086] The calculating the accuracy Pa of the pressure sensor 1 to be tested includes: Pa is equal to the difference between the output value Pd of the pressure sensor 1 to be tested and the corresponding output value Pr of the reference pressure sensor 2;

[0087] The calculating the sensitivity Ps of the pressure sensor 1 to be tested includes: calculating a plurality of sensitivities Ps1, Ps2, ..., Psm of the pressure sensor 1 to be tested, and taking an average value, wherein m=n-1.

[0088] Specifically, by setting the value range of n between 2 and 5, it is possible to obtain the output values ​​Pd of multiple groups of pressure sensors 1 to be tested and the corresponding output values ​​Pr of multiple groups of reference pressure sensors 2, so as to calculate one or more accuracies Pa, and thus to calculate one or more sensitivities Ps. While simplifying the measurement method, it is possible to improve the measurement accuracy by averaging multiple measurements and obtain a more reliable sensitivity value.

[0089] Optionally, n is 2, the pressure sensor 1 to be tested includes a first state and a second state, and the pressure sensor 1 to be tested can be switched between the first state and the second state by rotating the pressure sensor 1 to be tested, wherein the range of the rotation angle is 30° to 180°.

[0090] Specifically, in the first state, the pressure sensor 1 to be tested and the reference pressure sensor 2 are both in the first position, and the acceleration acting on the sensing chip of the pressure sensor 1 to be tested is a1; in the second state, the pressure sensor 1 to be tested and the reference pressure sensor 2 are both in the second position, and the acceleration acting on the sensing chip of the pressure sensor 1 to be tested is a2, and a2 is not equal to a1. In this way, the sensitivity of the pressure sensor 1 to be tested can be obtained by the above method, which is convenient for evaluating the sensing accuracy and response capability of the pressure sensor 1 to be tested.

[0091] The first state and the second state, that is, the first position and the second position, of the pressure sensor 1 to be tested can be achieved by rotating or flipping, so as to adjust the acceleration a acting on the sensing chip of the pressure sensor 1 to be tested.

[0092] Optionally, by flipping the pressure sensor 1 to be tested so that the pressure sensor 1 to be tested can switch between a first state and a second state, the acceleration acting on the sensing chip of the pressure sensor 1 to be tested in the first state is equal in magnitude and opposite in direction to the acceleration acting on the sensing chip of the pressure sensor 1 to be tested in the second state.

[0093] The positive direction is vertically downward, such as Figure 2 As shown in FIG. 1 , the acceleration acting on the sensing chip of the pressure sensor 1 to be tested is +g. Figure 3As shown, the acceleration acting on the sensing chip of the pressure sensor 1 to be tested is -g. By flipping the flip table 3, the pressure sensor 1 to be tested can change from the first state to the second state, and the corresponding change in acceleration a is 2g. This placement method can directly use the gravity acceleration for reading, without the need for an additional acceleration sensor, and also saves measurement costs.

[0094] Optionally, it also includes:

[0095] The pressure sensor to be tested 1 and the reference pressure sensor 2 are placed on a turntable 4, and the pressure sensor to be tested 1 is perpendicular to the centrifugal acceleration direction of the turntable 4, and the reference pressure sensor 2 is parallel to the centrifugal acceleration direction of the turntable 4. The centrifugal acceleration of the turntable 4 is adjusted so that the pressure sensor to be tested 1 and the reference pressure sensor 2 can be in different states.

[0096] like Figure 4 As shown, the centrifugal acceleration direction of the turntable 4 is horizontal, and the sensing chip of the pressure sensor 1 to be tested is in a vertical direction, so that the centrifugal acceleration of the turntable 4 can act vertically on the sensing chip of the pressure sensor 1 to be tested, so that the acceleration acting on the sensing chip of the pressure sensor 1 to be tested can be obtained by measuring the centrifugal acceleration of the turntable 4. The sensitive axis direction of the acceleration sensor for measuring the centrifugal acceleration of the turntable 4 is set to be consistent with the centrifugal acceleration direction of the turntable 4, so as to improve the reliability of the acceleration measurement result.

[0097] By adjusting the centrifugal acceleration of the turntable 4, the output value Pd of the pressure sensor 1 to be tested, the corresponding output value Pr of the reference pressure sensor 2 and the acceleration a output by the acceleration sensor are obtained after the turntable 4 is stabilized. The sensitivity of the pressure sensor 1 to be tested can be obtained through the above method, so as to evaluate the sensing accuracy and response capability of the pressure sensor 1 to be tested.

[0098] Optionally, the centrifugal acceleration direction of the turntable 4 is horizontal, and the sensing chip of the pressure sensor 1 to be tested is in a vertical direction, so that the centrifugal acceleration of the turntable 4 can act vertically on the sensing chip of the pressure sensor 1 to be tested, thereby obtaining the acceleration acting on the sensing chip of the pressure sensor 1 to be tested by measuring the centrifugal acceleration of the turntable 4.

[0099] Optionally, it also includes:

[0100] The pressure sensor to be tested 1 and the reference pressure sensor 2 are placed on a vibration table 5, and the vibration direction of the pressure sensor to be tested 1 is perpendicular to that of the vibration table 5, and the vibration direction of the reference pressure sensor 2 is parallel to that of the vibration table 5. During the vibration of the vibration table 5, the pressure sensor to be tested 1 and the reference pressure sensor 2 are in different states.

[0101] like Figure 5 As shown, the vibration direction of the vibration table 5 is the vertical direction, and the sensing chip of the pressure sensor 1 to be tested is in the horizontal direction, so that the vibration acceleration of the vibration table 5 can act vertically on the sensing chip of the pressure sensor 1 to be tested, so that the acceleration acting on the sensing chip of the pressure sensor 1 to be tested can be obtained by measuring the vibration acceleration of the vibration table 5. The sensitive axis direction of the acceleration sensor for measuring the vibration acceleration of the vibration table 5 is set to be consistent with the vibration acceleration direction of the vibration table 5, so as to improve the reliability of the acceleration measurement result.

[0102] By adjusting the amplitude, frequency and other measurement parameters of the vibration table 5, and continuously reading the output value Pd of the pressure sensor 1 to be tested, the corresponding output value Pr of the reference pressure sensor 2 and the acceleration a output by the acceleration sensor for a period of time after the vibration table 5 is stable, the sensitivity of the pressure sensor 1 to be tested can be obtained through the above method, so as to evaluate the sensing accuracy and response capability of the pressure sensor 1 to be tested. Among them, the amplitude of the vibration table 5 can be set to be no more than 10g, the frequency can be between 10Hz-100Hz, and the reading time can be no less than 1 minute for easy measurement.

[0103] Among them, since the vibration of the vibration table 5 is usually sinusoidal, that is, the output value of the pressure sensor 1 to be tested is read as AC Pd1, Pd2...Pdn, the output value of the reference pressure sensor 2 is read as AC Pr1, Pr2...Prn, and the acceleration output by the acceleration sensor is read as AC a1, a2...an, the effective value of the output value Pd of the pressure sensor 1 to be tested, the effective value of the output value Pr of the reference pressure sensor 2 and the effective value of the acceleration a output by the acceleration sensor can be calculated first, and then the accuracy Pa is calculated as Pd's effective value - Pr's effective value, and finally the ratio of the accuracy Pa to the effective value of the acceleration a output by the acceleration sensor is calculated to obtain the sensitivity of the pressure sensor 1 to be tested.

[0104] Optionally, the calculating the accuracy Pa of the pressure sensor 1 to be tested includes:

[0105] Pa is equal to the difference between the effective value of the output value Pd of the pressure sensor 1 to be tested and the effective value of the output value Pr of the reference pressure sensor 2;

[0106] After acquiring the accelerations a1, a2, ..., an acting on the sensing chip of the pressure sensor 1 to be tested in different states, the method further includes:

[0107] The effective value of the acceleration a acting on the sensing chip of the pressure sensor 1 to be tested is calculated.

[0108] Specifically, since the vibration of the vibration table 5 is usually sinusoidal, that is, the output values ​​read are all AC variable frequency signals, so when calculating the accuracy Pa of the pressure sensor 1 to be tested, the effective value of the output value is used instead of the instantaneous value. The effective value can reflect the average energy or power of the output signal over a period of time, and can better represent the true output characteristics of the pressure sensor 1 to be tested, thereby improving the accuracy and stability of the test, and also helping to more accurately evaluate the performance of the sensor in practical applications. Among them, the effective value can be the root mean square value obtained by performing root mean square processing on the output signal.

[0109] Furthermore, by calculating the effective value of the acceleration a, the average acceleration acting on the sensing chip of the pressure sensor 1 to be tested can also be more accurately reflected, thereby reducing the error caused by instantaneous acceleration fluctuations and further improving the reliability of the test results.

[0110] Optionally, before calculating the accuracy Pa of the pressure sensor 1 to be tested, the method further includes:

[0111] Performing filtering processing on the obtained output value Pd of the pressure sensor to be tested 1 and the output value Pr of the reference pressure sensor 2;

[0112] Before calculating the effective value of the acceleration a acting on the sensing chip of the pressure sensor 1 to be tested, the method further includes:

[0113] The acquired acceleration a acting on the sensing chip of the pressure sensor 1 to be tested is filtered.

[0114] Specifically, before calculating the accuracy Pa of the pressure sensor 1 to be tested and calculating the effective value of the acceleration a of the sensing chip acting on the pressure sensor 1 to be tested, the output values ​​Pd of multiple pressure sensors 1 to be tested, the output values ​​Pr of multiple reference pressure sensors 2, and the acceleration a of multiple sensing chips acting on the pressure sensor 1 to be tested are filtered respectively, which can effectively remove noise and interference signals and retain real and effective signal components, so that the calculated accuracy Pa and the effective value of acceleration a are closer to the real value, thereby improving the reliability of the test results.

[0115] In addition, filtering can also avoid the influence of outliers in the data on the test results, making the test results more stable and reliable.

[0116] Optionally, ΔPa is the accuracy Pa, Δa is the corresponding acceleration a, and the calculation of the sensitivity Ps of the pressure sensor 1 to be tested includes:

[0117] Ps is equal to the ratio of the accuracy Pa to the effective value of acceleration a.

[0118] Specifically, for the read AC variable frequency signal, after being processed and obtaining the effective value, the effective value can reflect the average energy or power of the output signal within a period of time, so the accuracy Pa can be directly calculated using the effective value of the output value Pd of the pressure sensor 1 to be tested and the effective value of the output value Pr of the reference pressure sensor 2, and the effective value of the acceleration a acting on the sensing chip of the pressure sensor 1 to be tested is used to replace the change in acceleration a. In this way, the sensitivity of the pressure sensor 1 to be tested can be obtained, so as to evaluate the sensing accuracy and response capability of the pressure sensor 1 to be tested.

[0119] Optionally, the sensing chip of the pressure sensor 1 to be tested and the sensing chip of the reference pressure sensor 2 are at the same height.

[0120] Specifically, the setting of the same height ensures that the sensing chip of the pressure sensor 1 to be tested and the sensing chip of the reference pressure sensor 2 can be subjected to the same acceleration during the test, thereby improving the consistency of the test conditions. This helps to more accurately evaluate the sensitivity of the pressure sensor 1 to be tested and reduces the errors caused by inconsistent test conditions. It also helps to improve test efficiency, reduce test costs, and maintain the accuracy of test results.

[0121] The embodiment of the present invention further provides a sensitivity calibration method of a pressure sensor, comprising:

[0122] Obtaining an initial sensitivity Psr of the pressure sensor at an initial position, wherein the initial sensitivity Psr is measured using the sensitivity testing method of the pressure sensor;

[0123] like Figure 6 As shown, the initial position may be a horizontal position, in which case the acceleration acting on the sensing chip of the pressure sensor is the gravitational acceleration g, and the initial sensitivity Psr corresponding to this state may be obtained through the above three test methods.

[0124] Obtaining a rotation angle θ of the pressure sensor relative to an initial position;

[0125] like Figure 7 As shown, an angle sensor 6 such as a gyroscope and an electronic digital display inclinometer can be used to monitor the rotation angle θ of the pressure sensor relative to the initial position, so as to facilitate subsequent calibration of the current sensitivity Psc.

[0126] The current sensitivity Psc of the pressure sensor is calculated, where Psc is equal to the product of Psr and cosθ.

[0127] In this way, the rotation angle θ of the pressure sensor relative to the initial position measured by the angle sensor 6 and combined with the cosine function can be used to calculate the current sensitivity Psc, thereby taking into account the component changes of the gravitational acceleration g in different postures and achieving accuracy calibration, thereby improving the measurement accuracy and reliability of the pressure sensor.

[0128] When the pressure sensor is used in a terminal, the rotation or swing of the terminal will cause the internal pressure sensor to rotate. Real-time calibration can timely detect and correct the error caused by the posture change of the pressure sensor, and maintain the stability and accuracy of the pressure sensor performance. Moreover, through automated measurement and calculation, the calibration process can be further simplified, the calibration cost can be reduced, and the accuracy of the calibration results can be maintained.

[0129] The embodiment of the present invention further provides a sensitivity calibration method of a pressure sensor, comprising:

[0130] Place the pressure sensor vertically so that the sensing chip of the pressure sensor is in a vertical direction, and obtain the output value Pdr of the pressure sensor at this time;

[0131] like Figure 8 As shown, when the pressure sensor is applied to a terminal, the position of the terminal can be adjusted so that the sensing chip of the pressure sensor therein is in a vertical direction, and the gravity acceleration of the waterproof gel will not act on the sensing chip. In this state, the output value Pdr of the pressure sensor at this time can be obtained as a reference value, and the reference value is not affected by the gravity of the waterproof gel.

[0132] Place the pressure sensor horizontally in a first direction, and obtain an output value Pd1 of the pressure sensor at this time;

[0133] When the pressure sensor is applied to a terminal, the sensing chip of the pressure sensor therein can be placed in a horizontal direction by adjusting the position of the terminal, for example Fig. 9 The opening of the pressure sensor in the middle is facing vertically upward. The vertical downward direction is the positive direction. Fig. 9 As shown, the acceleration acting on the sensing chip of the pressure sensor is +g. In this state, the output value Pd1 of the pressure sensor can be obtained, and the output value Pd1 is affected by the gravity of the waterproof gel.

[0134] Place the pressure sensor horizontally in a direction opposite to the first direction, and obtain an output value Pd2 of the pressure sensor at this time;

[0135] When the pressure sensor is applied to a terminal, the sensing chip of the pressure sensor therein can be placed in a horizontal direction by adjusting the position of the terminal, for example Fig.10The opening of the pressure sensor in the middle is facing vertically downward. Fig.10 As shown, the acceleration acting on the sensing chip of the pressure sensor is -g. In this state, the output value Pd2 of the pressure sensor can be obtained, and the output value Pd2 is affected by the gravity of the waterproof gel.

[0136] Calculate the accuracy Pa1 and Pa2 of the pressure sensor respectively, Pa1 is equal to the difference between the output value Pd1 of the pressure sensor and the output value Pdr of the pressure sensor, Pa2 is equal to the difference between the output value Pd2 of the pressure sensor and the output value Pdr of the pressure sensor;

[0137] Among them, Pa1=Pd1-Pdr, Pa2=Pd2-Pdr.

[0138] The sensitivity Ps of the pressure sensor is calculated, where Ps is equal to the ratio of the change in the accuracy Pa to the corresponding change in the acceleration a.

[0139] That is, Ps = (Pa1-Pa2) / 2g. In this way, by adjusting the position of the pressure sensor and measuring the output value of the pressure sensor in different postures, the sensitivity of the pressure sensor can be calibrated to remove the influence of foreign matter adhering to the waterproof gel on the measurement result of the pressure sensor, so that the pressure sensor can still maintain good measurement accuracy after long-term use.

[0140] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0141] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A sensitivity testing method for a pressure sensor, wherein the pressure sensor has a sensing chip, characterized in that: include: Obtain output values ​​Pd1, Pd2, ..., Pdn of the pressure sensor to be tested in different states and output values ​​Pr1, Pr2, ..., Prn of the reference pressure sensor, where n is an integer not less than 2; Calculating the accuracy Pa of the pressure sensor to be tested, where Pa is equal to the difference between the output value Pd of the pressure sensor to be tested and the output value Pr of the reference pressure sensor; Acquire accelerations a1, a2, ..., an acting on the sensing chip of the pressure sensor to be tested in different states; The sensitivity Ps of the pressure sensor to be tested is calculated, where Ps is equal to the ratio of ΔPa to Δa, wherein ΔPa is the change in accuracy Pa or the accuracy Pa, and Δa is the change in the corresponding acceleration a or the corresponding acceleration a.

2. The sensitivity testing method of a pressure sensor according to claim 1, characterized in that: ΔPa is the change in accuracy Pa, Δa is the corresponding change in acceleration a, and the value range of n is between 2 and 5; The calculating the accuracy Pa of the pressure sensor to be tested includes: Pa is equal to the difference between the output value Pd of the pressure sensor to be tested and the corresponding output value Pr of the reference pressure sensor; The calculating the sensitivity Ps of the pressure sensor to be tested includes: calculating a plurality of sensitivities Ps1, Ps2, ..., Psm of the pressure sensor to be tested, and taking an average value, wherein m=n-1.

3. The sensitivity testing method of the pressure sensor according to claim 2, characterized in that: n is 2, the pressure sensor to be tested includes a first state and a second state, and the pressure sensor to be tested can be switched between the first state and the second state by rotating the pressure sensor to be tested, wherein the range of the rotation angle is 30° to 180°.

4. The sensitivity testing method of the pressure sensor according to claim 3, characterized in that: By flipping the pressure sensor to be tested so that it can switch between a first state and a second state, the acceleration acting on the sensing chip of the pressure sensor to be tested in the first state is equal in magnitude and opposite in direction to the acceleration acting on the sensing chip of the pressure sensor to be tested in the second state.

5. The sensitivity testing method of a pressure sensor according to claim 2, characterized in that: Also includes: The pressure sensor to be tested and the reference pressure sensor are placed on a turntable, and the pressure sensor to be tested is perpendicular to the centrifugal acceleration direction of the turntable, and the reference pressure sensor is parallel to the centrifugal acceleration direction of the turntable. The centrifugal acceleration of the turntable is adjusted so that the pressure sensor to be tested and the reference pressure sensor can be in different states.

6. The sensitivity testing method of a pressure sensor according to claim 5, characterized in that: The centrifugal acceleration direction of the turntable is horizontal, and the sensing chip of the pressure sensor to be tested is in a vertical direction.

7. The sensitivity testing method of a pressure sensor according to claim 1, characterized in that: Also includes: The pressure sensor to be tested and the reference pressure sensor are placed on a vibration table, and the pressure sensor to be tested is perpendicular to the vibration direction of the vibration table, and the reference pressure sensor is parallel to the vibration direction of the vibration table. During the vibration of the vibration table, the pressure sensor to be tested and the reference pressure sensor are in different states.

8. The sensitivity testing method of a pressure sensor according to claim 7, characterized in that: The calculating the accuracy Pa of the pressure sensor to be tested comprises: Pa is equal to the difference between the effective value of the output value Pd of the pressure sensor to be tested and the effective value of the output value Pr of the reference pressure sensor; After acquiring the accelerations a1, a2, ..., an acting on the sensing chip of the pressure sensor to be tested in different states, the method further includes: The effective value of the acceleration a acting on the sensing chip of the pressure sensor to be tested is calculated.

9. The sensitivity testing method of a pressure sensor according to claim 8, characterized in that: Before calculating the accuracy Pa of the pressure sensor to be tested, the method further includes: Performing filtering processing on the obtained output value Pd of the pressure sensor to be tested and the output value Pr of the reference pressure sensor; Before calculating the effective value of the acceleration a acting on the sensing chip of the pressure sensor to be tested, the method further includes: The acquired acceleration a acting on the sensing chip of the pressure sensor to be tested is filtered.

10. The sensitivity testing method of a pressure sensor according to claim 8, characterized in that: ΔPa is the accuracy Pa, Δa is the corresponding acceleration a, and the calculation of the sensitivity Ps of the pressure sensor to be tested includes: Ps is equal to the ratio of the accuracy Pa to the effective value of acceleration a.

11. The sensitivity testing method of a pressure sensor according to claim 1, characterized in that: The sensing chip of the pressure sensor to be tested and the sensing chip of the reference pressure sensor are at the same height.

12. A method for calibrating the sensitivity of a pressure sensor, characterized in that: include: Obtaining an initial sensitivity Psr of the pressure sensor at an initial position, wherein the initial sensitivity Psr is measured by using the sensitivity testing method for the pressure sensor according to any one of claims 1 to 11; Obtaining a rotation angle θ of the pressure sensor relative to an initial position; The current sensitivity Psc of the pressure sensor is calculated, where Psc is equal to the product of Psr and cosθ.

13. A method for calibrating the sensitivity of a pressure sensor, characterized in that: include: Place the pressure sensor vertically so that the sensing chip of the pressure sensor is in a vertical direction, and obtain the output value Pdr of the pressure sensor at this time; Place the pressure sensor horizontally in a first direction, and obtain an output value Pd1 of the pressure sensor at this time; Place the pressure sensor horizontally in a direction opposite to the first direction, and obtain an output value Pd2 of the pressure sensor at this time; Calculate the accuracy Pa1 and Pa2 of the pressure sensor respectively, Pa1 is equal to the difference between the output value Pd1 of the pressure sensor and the output value Pdr of the pressure sensor, Pa2 is equal to the difference between the output value Pd2 of the pressure sensor and the output value Pdr of the pressure sensor; The sensitivity Ps of the pressure sensor is calculated, where Ps is equal to the ratio of the change in the accuracy Pa to the corresponding change in the acceleration a.

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