Pyroelectric multichannel parallel test device and test method

Abstract

The invention discloses a pyroelectric multichannel parallel testing device and testing method, and belongs to the technical field of pyroelectric testing of probe detection. The problem that in the prior art, a traditional pyroelectric testing device and a traditional pyroelectric testing method are low in testing efficiency is solved. The invention provides a pyroelectric multichannel parallel testing device which is characterized in that a temperature sensor and a heater are connected with a sample table, a high-low temperature heat table comprises the temperature sensor and the heater, the sample table and a multichannel testing clamp, the multichannel testing clamp comprises a probe table and probes on the probe table, the sample table is connected with the probe table, and the probe table is connected with the high-low temperature heat table. The multi-channel test clamp is connected with the multi-channel switching module and the electrometer. The temperature control module is respectively connected with the temperature sensor, the heater and the air pump; the air pump is respectively connected with the liquid nitrogen tank and the sample table; the main control end is connected with the temperature control module, the multi-channel switching module and the electrometer. According to the invention, the test efficiency is improved, automatic temperature regulation in a low-temperature and high-temperature range is realized, and the device can be applied to multi-sample pyroelectric test.

Description

Technical Field

[0001] The present invention relates to a pyroelectric multi-channel parallel testing device and a testing method, belonging to the technical field of pyroelectric testing based on probe detection. Background Art

[0002] In recent years, sensors and transducers used in high- and low-temperature environments in fields such as aviation, aerospace, and deep-sea applications have placed new demands on information-functional ceramics, necessitating characterization of the temperature characteristics of their related properties, the most fundamental of which is pyroelectricity. Temperature has a significant impact on the performance, structure, use, and preservation of materials, and even near certain critical temperatures, material properties exhibit significant differences. For information-functional materials, studying their pyroelectric properties at different temperature ranges is one of the most important methods for understanding the interplay between material polarization, microscopic mechanisms, composition, structure, and properties. Therefore, developing pyroelectric measurement solutions with wider temperature ranges, greater accuracy, and the ability to conduct multi-channel parallel testing has become a key focus and challenge for researchers in related fields.

[0003] The pyroelectric effect refers to the phenomenon that the polar regions inside a pyroelectric material fluctuate due to changes in external temperature, causing the spontaneous polarization intensity to change, thereby causing a change in the number of free charges on the outer surface. Pyroelectric properties are the most basic characterization method for studying dielectric materials, and their results determine the application potential and application environment of the material. Currently, existing technologies can achieve testing in a narrow temperature range and low temperature variation rate, and mature testing equipment is already available. Subsequently, there has been some progress in the measurement of pyroelectric properties. Currently, scientific researchers can build test systems with different temperature ranges (room temperature to 200°C, temperature variation rate of 5 to 20°C / min, etc.).

[0004] However, existing pyroelectric testing devices and testing methods have the following problems: (1) The system integration is not high, the operation is complicated, the degree of automation is low, and most of the measurements are manual; (2) Only one sample can be tested at a time. Since the test process requires heating and cooling, it is a long test process. A single station cannot meet a large number of test needs, and the test efficiency is low; (3) It generally does not have the test function of the low-temperature part.

[0005] In summary, a pyroelectric multi-channel parallel testing device and testing method with a higher degree of automation, a test temperature range that meets the requirements of most materials, and higher testing efficiency is needed. Summary of the Invention

[0006] A brief overview of the present invention is provided below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify key or important aspects of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is simply to present certain concepts in a simplified form as a prelude to the more detailed description discussed later.

[0007] In view of this, in order to solve the problem of low testing efficiency of conventional pyroelectric testing devices and testing methods in the prior art, the present invention provides a pyroelectric multi-channel parallel testing device and testing method.

[0008] Technical solution 1 is as follows: a pyroelectric multi-channel parallel testing device, including a temperature control module, a high and low temperature hot stage, a liquid nitrogen tank, an air pump, a multi-channel switching module, a main control terminal and an electrometer;

[0009] The high and low temperature hot stage includes a temperature sensor and a heater, a sample stage and a multi-channel test fixture, the temperature sensor and the heater are connected to the sample stage, the multi-channel test fixture includes a probe stage and a probe thereon, the sample stage is connected to the probe stage, and the multi-channel test fixture is connected to the multi-channel switching module and the electrometer respectively;

[0010] The temperature control module is connected to the temperature sensor, the heater and the air pump respectively, and the air pump is connected to the liquid nitrogen tank and the sample stage respectively;

[0011] The main control end is connected to the temperature control module, the multi-channel switching module and the electrometer respectively.

[0012] Furthermore, the multi-channel test fixture has four probes, among which one probe is connected to one electrode surface of the four samples on the sample table as a common end, and the other four probes are respectively connected to the other electrode surfaces of the four samples. The four probes are respectively connected to the four channels of the multi-channel switching module. The four probes are also respectively connected to the electrometer. The on and off of the loop is controlled by the multi-channel switching module, and the sample current is collected by the electrometer to realize multi-channel testing of the sample.

[0013] Technical Solution 2 is as follows: A pyroelectric multi-channel parallel testing method, using a pyroelectric multi-channel parallel testing device described in Technical Solution 1, includes the following steps:

[0014] S1. Enter the test conditions in the software operation interface of the main control terminal;

[0015] S2. Clamp the four test samples in the multi-channel test fixture and click Start. The test program sends commands to the temperature control module via the serial port. The temperature control module uses a PID algorithm to control the output power and sets the voltage across the sample using the high and low temperature hot stages. The temperature of the test samples first rises to the set temperature rise value and then falls to the set temperature fall value.

[0016] S3. During the temperature ramp, the test program continuously collects temperature information. When the temperature rises or falls by 1°C, the master control terminal controls the multi-channel switching module via the serial port line, connects the current channel, and uses the electrometer to measure the current of the current sample, which is then transmitted back to the master control terminal via the serial port line.

[0017] S4. Repeat step S3, the multi-channel switching module disconnects the current channel and connects the next channel until the pyroelectric current values of the four samples at a certain temperature are obtained. As the temperature rises / falls, the above test process is continued to finally obtain the pyroelectric coefficients of the four samples at different temperatures during the temperature rise and fall process.

[0018] Furthermore, in step S2, the control process of the PID algorithm is expressed as follows: the PID algorithm calculates the ideal temperature rise and fall program segment through the test conditions, and sets the theoretical temperature T m Corresponding to time t, the theoretical temperature T is obtained m The corresponding relationship with time t;

[0019] Theoretical temperature T m The corresponding relationship with time t is expressed as:

[0020] T m =T(t)

[0021] Where T(t) is the time function;

[0022] According to the current actual temperature signal T transmitted to the temperature control module by the temperature sensor true , get the difference ΔT between the actual temperature and the theoretical temperature;

[0023] The difference ΔT between the actual temperature and the theoretical temperature is expressed as:

[0024] ΔT=T m -T true

[0025] The current output power P is calculated by the PID algorithm. n ;

[0026] Current output power P n Expressed as:

[0027] P n =P n-1 +k p (ΔT n -ΔT n-1 )+k p k i ΔT n +k p k d (ΔT n -2ΔTn-1 +ΔT n-2 )

[0028] Among them, k p 、k i 、k d is the control factor, ΔT n-1 is the temperature difference at the next moment, ΔT n-2 is the temperature difference ΔT at the next moment n-1 The temperature difference at the next moment;

[0029] Temperature control is achieved by selecting the value of the control factor.

[0030] Furthermore, in step S4, a pyroelectric coefficient P is defined;

[0031] The pyroelectric coefficient P is expressed as:

[0032] P=dP S / dT

[0033] Among them, P S is the spontaneous polarization intensity, T is the temperature, and the pyroelectric current I of the sample to be tested is directly measured through the process of heating and cooling. p , obtain the curve of pyroelectric current changing with temperature, and obtain the pyroelectric coefficient p at different temperatures;

[0034] The pyroelectric coefficient p at different temperatures is expressed as:

[0035]

[0036] The beneficial effects of the present invention are as follows: the present invention controls the temperature of the temperature sensor and heater, liquid nitrogen tank, and air pump of the high and low temperature hot stage through a temperature control module based on PID control, thereby realizing temperature rise and fall regulation during the test process, and at the same time having the test function of the low temperature part; the present invention is based on centralized control at the main control end, with high integration, simple operation, and a high degree of automation. No manual testing is required, and automatic temperature adjustment can be achieved according to the input test conditions to obtain the test results; the present invention solves the problem that the pyroelectric test device can only test one sample at a time, greatly improving the test efficiency, and further improving the accuracy through the multi-channel switching module and the single-channel connection of the electrometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0038] Figure 1 This is a structural diagram of a pyroelectric multi-channel parallel testing device;

[0039] Figure 2 The figure is a flow chart of a pyroelectric multi-channel parallel testing method;

[0040] Figure 3 It is a structural diagram of temperature control based on PID algorithm;

[0041] Figure 4 Schematic diagram of the housing structure of the electrometer;

[0042] Figure 5 Schematic diagram of the shell structure of the temperature control box;

[0043] Figure 6 It is a structural diagram of the high and low temperature hot stage;

[0044] Figure 7 This is a schematic diagram of the software operation interface of the main control terminal;

[0045] Figure 8 This is the test result of the low temperature narrow temperature range;

[0046] Figure 9 This is the test result of the high temperature part in a wide temperature range.

[0047] Description of the figures: 1. Temperature control module; 2. High and low temperature hot plate; 3. Liquid nitrogen tank; 4. Air pump; 5. Multi-channel switching module; 6. Main control terminal; 7. Temperature sensor and heater; 8. Sample stage; 9. Multi-channel test fixture; 10. Electrometer; 11-24. Ports; 25. Common port; 26. Temperature control terminal data cable; 27. Hot plate water cooling circulation pipeline; 28. Heating silver ingot with insulating coating; 29. Hot plate power supply line; 30. Liquid nitrogen circulation system pipeline; 31. Probe station. DETAILED DESCRIPTION

[0048] To make the technical solutions and advantages of the embodiments of the present invention more clearly understood, exemplary embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It should be noted that the embodiments described are only a portion of the embodiments of the present invention, and are not an exhaustive list of all embodiments. It should be noted that the embodiments of the present invention and the features thereof may be combined with each other unless they conflict.

[0049] Example 1: Reference Figure 1-9 Detailed description of this embodiment, a pyroelectric multi-channel parallel testing device includes a temperature control module 1, a high and low temperature hot stage 2, a liquid nitrogen tank 3, an air pump 4, a multi-channel switching module 5, a main control terminal 6 and an electrometer 10;

[0050] The high and low temperature hot stage 2 includes a temperature sensor and heater 7, a sample stage 8 and a multi-channel test fixture 9, the temperature sensor and heater 7 are connected to the sample stage 8, the multi-channel test fixture 9 includes a probe station 31 and a probe thereon, the sample stage 8 is connected to the probe station 31, and the multi-channel test fixture 9 is connected to the multi-channel switching module 5 and the electrometer 10 respectively;

[0051] The temperature control module 1 is connected to the temperature sensor, the heater 6 and the air pump 4 respectively, and the air pump 4 is connected to the liquid nitrogen tank 3 and the sample stage 7 respectively;

[0052] The main control terminal 6 is connected to the temperature control module 1 , the multi-channel switching module 5 and the electrometer 10 respectively.

[0053] Furthermore, the multi-channel test fixture 9 has five probes, which are made of beryllium copper gold-plated material. Among them, one probe is connected to one electrode surface of the four samples on the sample table 8 as a common end, and the other four probes are respectively connected to the other electrode surfaces of the four samples. The four probes are respectively connected to the four channels of the multi-channel switching module 5. The four probes are also respectively connected to the electrometer 10. The on and off of the circuit is controlled by the multi-channel switching module 5, and the sample current is collected by the electrometer 10 to realize multi-channel testing of the sample.

[0054] Specifically, the present invention mainly includes two parts: temperature control and current collection. Among them, temperature control is mainly achieved by controlling the temperature sensor and heater 7 according to the PID algorithm by the temperature control module 1 to realize temperature transmission and heating; current collection is achieved by the sample multi-channel test fixture 9, the multi-channel switching module 5, etc. The multi-channel switching module 5, the electrometer 10 and the temperature control module 1 are respectively connected to the main control terminal 6, i.e., the PC, through the communication port and the communication serial port line. Under the control of the software in the PC, the coordinated linkage of the control-test unit is realized, and the current generated by the pyroelectric effect of the sample can be tested. Figure 3 , the temperature control display module is the temperature control module;

[0055] The main control terminal 6 is connected to the multi-channel switching module 5 through the RS-232 serial port. The function of the multi-channel switching module 5 is to receive the instructions sent by the main control terminal 6 through the serial port to switch the signal. Its main control chip U2 adopts the domestic microcontroller (MCU) model STC12C2052 of Hongjing Technology. The main function of chip U2 is to convert RS232 level and TTL level. The microcontroller processes the signal after the level conversion of U1 and parses the instruction sent by the host. According to the instruction, the corresponding input and output port (IO) controls the signal relay to control the signal, thereby realizing signal switching. In order to ensure that the signal is not interfered with, the signal switching board has shielded the signal line;

[0056] In this embodiment, the temperature sensor and heater 7 are implemented by a constant temperature box, the heater is a heating ceramic piece, the temperature sensor is a temperature measuring thermocouple, and the temperature control module 1 controls the temperature of the liquid nitrogen circulation system composed of the constant temperature box, the liquid nitrogen tank 3 and the air pump 4 through a PID algorithm;

[0057] refer to Figure 6 The high and low temperature hot stage 2 is an integrated chamber for temperature rise and fall. Port 11 is the interface connected to the common port 25. Ports 12 to 15 are respectively connected to the four probes in the chamber. The lines are represented by black thick dashed lines and are connected to the electrometer 10 through the BNC port to collect current signals. Ports 16 and 17 are the connection ports of the temperature control end data line entity 26, which are internally connected to the heating ceramic piece and the temperature measuring thermocouple, and externally connected to the temperature control module 1; Ports 18 to 21 are the connection ports of the hot stage water cooling circulation pipeline 27, which maintains the chamber shell at extremely low / extreme temperatures. The mechanical structure is stable at high temperatures; ports 22 and 23 are the input and output circulation ports of the liquid nitrogen circulation system pipeline 30, which are used to achieve a low-temperature environment in the chamber and cooperate with the heating ceramic to achieve fine temperature control of the heating process; port 24 is the power supply port of the high and low temperature heating stage 2, which is connected to the heating stage power supply line 29. The heating silver ingot 28 with an insulating coating is used to heat the silver ingot 28. A heating ceramic piece is embedded in the silver ingot 28 to achieve uniform heat distribution over a larger area when in contact with the sample, and together with the liquid nitrogen circulation system, achieve fine temperature control of the heating and cooling process.

[0058] Example 2: Reference Figure 1-9 This embodiment is described in detail. A pyroelectric multi-channel parallel testing method, using the pyroelectric multi-channel parallel testing device described in Example 1, includes the following steps:

[0059] S1. Enter the test conditions in the software operation interface of the main control terminal;

[0060] S2. Clamp the four test samples in the multi-channel test fixture and click Start. The test program sends commands to the temperature control module via the serial port. The temperature control module uses a PID algorithm to control the output power and sets the voltage across the sample using the high and low temperature hot stages. The temperature of the test samples first rises to the set temperature rise value and then falls to the set temperature fall value.

[0061] S3. During the temperature ramp, the test program continuously collects temperature information. When the temperature rises or falls by 1°C, the master control terminal controls the multi-channel switching module via the serial port line, connects the current channel, and uses the electrometer to measure the current of the current sample, which is then transmitted back to the master control terminal via the serial port line.

[0062] S4. Repeat step S3, the multi-channel switching module disconnects the current channel and connects the next channel until the pyroelectric current values of the four samples at a certain temperature are obtained. As the temperature rises / falls, the above test process is continued to finally obtain the pyroelectric coefficients of the four samples at different temperatures during the temperature rise and fall process.

[0063] Specifically, in this embodiment, reference Figure 7 , the test conditions are expressed as: starting temperature (20℃), heating temperature (214℃), heating time (1min), cooling temperature (172℃), cooling time (1min), recording interval (1s), and number of cycles (1 time); the test limits are expressed as: minimum test temperature (-200℃), maximum test temperature (600℃), starting temperature (25℃), target heating temperature (50℃), heating time (25min, heating rate 1℃ / min), target cooling temperature (-50℃), cooling time (100min, cooling rate 1℃ / min), recording interval (1℃) and number of cycles (10 times); after heating the temperature from 25℃ to 50℃ in 25min, it took 100min to reduce the temperature to -50℃;

[0064] The present invention has a multi-channel (typically four-channel) pyroelectric test function, which can complete wide temperature range and low current testing. The specific parameters are as follows:

[0065] Temperature range: -200℃~600℃;

[0066] Temperature change rate: 0.01℃ / min~150℃ / min;

[0067] Current range: 0.0001pA~20mA;

[0068] Number of samples: Up to 4 samples can be tested simultaneously.

[0069] Furthermore, in step S2, the control process of the PID algorithm is expressed as follows: the PID algorithm calculates the ideal temperature rise and fall program segment through the test conditions, and sets the theoretical temperature T m Corresponding to time t, the theoretical temperature T is obtained m The corresponding relationship with time t;

[0070] Theoretical temperature T m The corresponding relationship with time t is expressed as:

[0071] T m =T(t)

[0072] Where, T(t) is the time function;

[0073] According to the current actual temperature signal T transmitted to the temperature control module by the temperature sensor true , get the difference ΔT between the actual temperature and the theoretical temperature;

[0074] The difference ΔT between the actual temperature and the theoretical temperature is expressed as:

[0075] ΔT=T m-T true

[0076] The current output power P is calculated by the PID algorithm. n ;

[0077] Current output power P n Expressed as:

[0078] P n =P n-1 +k p (ΔT n -ΔT n-1 )+k p k i ΔT n +k p k d (ΔT n -2ΔT n-1 +ΔT n-2 )

[0079] Among them, k p 、k i 、k d is the control factor, ΔT n-1 is the temperature difference at the next moment, ΔT n-2 is the temperature difference ΔT at the next moment n-1 The temperature difference at the next moment;

[0080] Temperature control is achieved by selecting the value of the control factor.

[0081] Specifically, the initial value of the PID algorithm is parameter k p =20,k i =1, and k d =0, in addition, during the temperature control process, the self-learning of the test program can achieve appropriate adjustment of the control factor.

[0082] Furthermore, in step S4, for the same material, the faster the temperature changes, the greater the pyroelectric current. In order to characterize the strength of the pyroelectric performance of different materials, a pyroelectric coefficient P is defined;

[0083] The pyroelectric coefficient P is expressed as:

[0084] P=dP S / dT

[0085] Among them, P Sis the spontaneous polarization intensity, T is the temperature, and the larger the absolute value of the pyroelectric coefficient, the stronger the heat-to-electricity conversion ability of the material. The direct method is used to characterize the pyroelectric performance. The direct method not only meets the zero electric field condition, but also can obtain the pyroelectric current in a continuous temperature range. By heating and cooling the sample, the pyroelectric current I p , obtain the curve of pyroelectric current changing with temperature, and obtain the pyroelectric coefficient p at different temperatures;

[0086] The pyroelectric coefficient p at different temperatures is expressed as:

[0087]

[0088] Although the present invention has been described with respect to a limited number of embodiments, it will be apparent to those skilled in the art, having benefit of the foregoing description, that other embodiments are contemplated within the scope of the invention thus described. Furthermore, it should be noted that the language used in this specification has been selected primarily for readability and didactic purposes, rather than for the purpose of explaining or limiting the subject matter of the present invention. Consequently, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is intended to be illustrative rather than restrictive of the scope of the invention, which is defined by the appended claims.

Claims

1. A pyroelectric multi-channel parallel testing device, characterized in that: It includes a temperature control module (1), a high and low temperature heating stage (2), a liquid nitrogen tank (3), an air pump (4), a multi-channel switching module (5), a main control terminal (6) and an electrometer (10); The high and low temperature heating stage (2) includes a temperature sensor and a heater (7), a sample stage (8) and a multi-channel test fixture (9), wherein the temperature sensor and the heater (7) are connected to the sample stage (8), the multi-channel test fixture (9) includes a probe stage (31) and a probe thereon, the sample stage (8) is connected to the probe stage (31), and the multi-channel test fixture (9) is connected to the multi-channel switching module (5) and the electrometer (10), respectively; The temperature control module (1) is connected to the temperature sensor and heater (6) and the air pump (4) respectively, and the air pump (4) is connected to the liquid nitrogen tank (3) and the sample stage (7) respectively; The main control terminal (6) is connected to the temperature control module (1), the multi-channel switching module (5) and the electrometer (10) respectively.

2. The pyroelectric multi-channel parallel testing device according to claim 1, characterized in that: The multi-channel test fixture (9) has five probes, wherein one probe is connected to one electrode surface of four samples on the sample table (8) as a common end, and the other four probes are respectively connected to the other electrode surfaces of the four samples. The four probes are respectively connected to the four channels of the multi-channel switching module (5). The four probes are also respectively connected to the electrometer (10). The on-off of the circuit is controlled by the multi-channel switching module (5), and the sample current is collected by the electrometer (10) to realize the multi-channel test of the sample.

3. A pyroelectric multi-channel parallel testing method, characterized in that: A pyroelectric multi-channel parallel testing device according to any one of claims 1 to 2 is used, comprising the following steps: S1. Enter the test conditions in the software operation interface of the main control terminal; S2. Clamp the four test samples in the multi-channel test fixture and click Start. The test program sends commands to the temperature control module via the serial port. The temperature control module uses a PID algorithm to control the output power and sets the voltage across the sample using the high and low temperature hot stages. The temperature of the test samples first rises to the set temperature rise value and then falls to the set temperature fall value. S3. During the temperature ramp, the test program continuously collects temperature information. When the temperature rises or falls by 1°C, the master control terminal controls the multi-channel switching module via the serial port line, connects the current channel, and uses the electrometer to measure the current of the current sample, which is then transmitted back to the master control terminal via the serial port line. S4. Repeat step S3, the multi-channel switching module disconnects the current channel and connects the next channel until the pyroelectric current values of the four samples at a certain temperature are obtained. As the temperature rises / falls, the above test process is continued to finally obtain the pyroelectric coefficients of the four samples at different temperatures during the temperature rise and fall process.

4. The pyroelectric multi-channel parallel testing method according to claim 3, characterized in that: In step S2, the control process of the PID algorithm is expressed as follows: the PID algorithm calculates the ideal temperature rise and fall program segment through the test conditions, and sets the theoretical temperature T m Corresponding to time t, the theoretical temperature T is obtained m The corresponding relationship with time t; Theoretical temperature T m The corresponding relationship with time t is expressed as: T m =T(t) Where, T(t) is the time function; According to the current actual temperature signal T transmitted to the temperature control module by the temperature sensor true , get the difference ΔT between the actual temperature and the theoretical temperature; The difference ΔT between the actual temperature and the theoretical temperature is expressed as: ΔT=T m -T true The current output power P is calculated by the PID algorithm. n ; Current output power P n Expressed as: P n =P n-1 +k p (ΔT n -ΔT n-1 )+k p k i ΔT n +k p k d (ΔT n -2ΔT n-1 +ΔT n-2 ) Among them, k p 、k i 、k d is the control factor, ΔT n-1 is the temperature difference at the next moment, ΔT n-2 is the temperature difference ΔT at the next moment n-1 The temperature difference at the next moment; Temperature control is achieved by selecting the value of the control factor.

5. The pyroelectric multi-channel parallel testing method according to claim 4, characterized in that: In the step S4, a pyroelectric coefficient P is defined; The pyroelectric coefficient P is expressed as: P=dP S / dT Among them, P S is the spontaneous polarization intensity, T is the temperature, and the pyroelectric current I of the sample to be tested is directly measured through the process of heating and cooling. p , obtain the curve of pyroelectric current changing with temperature, and obtain the pyroelectric coefficient p at different temperatures; The pyroelectric coefficient p at different temperatures is expressed as:

Images