CN116381451A - Testing device and method for welding open-circuit single-ended planting needle based on thermosensitive piece - Google Patents

Abstract

The invention provides a test device and method based on thermal sheet welding open-short single-end single-end needle implantation, the method includes providing an excitation source signal from a test circuit board and touching the FPC/FFC gold soldered with a thermal sheet through a test probe. At one end of the finger, the excitation source signal flows through the circuit formed by the internal circuit of the thermal chip through the FPC/FFC line, and the resistance value and voltage voltage between the protection circuit between the internal related signal PIN pin of the thermal chip IC and GND are detected. According to the set normal threshold, by switching each PIN pin measurement to determine whether the corresponding line has abnormal welding quality; after the test is completed, the test result is output through the test result output circuit. The application of the present invention can solve the problems in the prior art that the cost is too high, the open circuit test cannot be performed, the misjudgment rate is high, material resources, manpower and time are wasted too much, so as to achieve low cost, and the open and short circuit test is performed at the same time, with high accuracy and labor saving Material and other purposes.

Description

A test device and method for single-end needle implantation based on thermal sheet welding open-short circuit

technical field

The invention relates to the technical field of electronic component testing, in particular to a testing device based on thermal sheet welding open-short-circuit single-end needle planting and a testing method using the device.

Background technique

At present, the thermal film, the key component of the thermal printer, must be soldered to the flexible circuit board (specifically, FPC and FFC). Due to the technical reasons of the welding process, the test probe can only be implanted on the gold finger of the flexible circuit board. It is not possible to solder the terminal pin at the other end, which belongs to the single-ended test method.

After the thermal sheet is welded to the flexible circuit board, it is necessary to test whether the welding quality of the thermal sheet is qualified. At present, there are two main methods in China: one is a professional ICT (on-line tester) or ATE (on-line multi-function tester). The first way is to match a professional tester with a computer, which is expensive. The imported models of the brand are all above 100,000 RMB, and the domestic non-branded models are also above 30,000 RMB, and professional personnel are required to write the software for the test items, which takes up a large space, and the instrument needs to be returned to the factory for repair if it is damaged. , the maintenance cost is high, and this test method is generally difficult for small enterprises in the domestic thermal printer industry to popularize; Different networks are grouped into groups A and B. Groups A and B correspond to the red and black test leads of the multimeter. Turn on the beep file of the multimeter to test whether the PINs of different adjacent networks are short-circuited. If there is a short circuit, the multimeter buzzer will sound . However, this test has many bad drawbacks, namely:

1. It is impossible to test whether the thermal pad welding is open;

2. If the test probe does not touch the corresponding PIN of the gold finger of the flexible circuit board or the probe is stuck or the needle cover on the probe is broken, the multimeter can only measure the short circuit and cannot measure the open circuit, resulting in buzzing. Misjudgment caused by the device not beeping;

3. Due to this test method, it is impossible to test the welding open circuit and misjudgment, which caused the thermal film to be assembled in the post-process assembly movement. The movement was disassembled due to poor welding of the thermal film, and the thermal film was repaired and then assembled for testing. A lot of repetitive work caused by the finished product testing of the movement has resulted in a lot of waste of material resources, manpower and time.

Contents of the invention

The present invention provides a test device and method based on thermal sheet welding open-short-circuit single-end needle planting, which is mainly used to solve the problem of high cost, inability to perform open-circuit test, high misjudgment rate, and excessive waste of material resources in the prior art. manpower and time issues.

The present invention achieves the above object through the following technical solutions:

A test device based on thermal sheet welding open-short-circuit single-ended needle implantation, including test probes installed on the test tool, a test circuit board, an external signal input circuit, and a test result output circuit. The test circuit board passes through the test probe. The needle touches one end of the FPC/FFC gold finger welded with the thermal sheet, and outputs an excitation source signal to it, and the excitation source signal flows through the circuit formed by the internal circuit of the thermal sheet through the FPC/FFC line, and is used to detect the thermal sensor. The resistance value and the voltage drop of the protection circuit between the related signal PIN pin and GND in the chip IC; after the test is completed, the test circuit board outputs the test result signal to the test result output circuit, and the test result output circuit Output test results;

Wherein, the test circuit board includes an MCU main control circuit, an excitation source circuit, an ADC data acquisition circuit, an input and output IO control module, an analog switch switching circuit, and a voltage follower circuit, and the excitation source circuit provides a stable voltage for the test circuit board. A piezoelectric power source, the ADC data acquisition circuit is used to collect the real voltage signal of the measured target, and feeds back to the MCU main control circuit, and the MCU main control circuit communicates with the external signal input through the input and output IO control module circuit connection, the analog switch switching circuit is connected to the test probe through a pin switching circuit, and the voltage follower circuit is connected to the excitation source circuit.

A further scheme is that a test probe needle mold is provided on the test tool, and the test probe is placed in the test probe needle mold. When installing and testing, the test product is put into the needle mold groove, After the infrared sensor senses that the product under test is put in, it triggers the cylinder to press down, and the magnetic induction switch installed on the side of the cylinder senses that the pressure is in place, and the test starts automatically.

A further solution is that the external signal input circuit includes a switch button and an electromagnetic inductor, and the MCU main control circuit is respectively connected to the switch button and the electromagnetic inductor through the input and output IO control module.

A further solution is that the test result output circuit includes an LCD display, a test result indicator light and an alarm unit, and the MCU main control circuit is connected to the LCD display, the test result indicator light and the alarm unit respectively.

A test method based on thermal sheet welding open-short-circuit single-end needle implantation, which is applied to the above-mentioned test device based on thermal sheet welding open-short-circuit single-end needle implantation for testing, including:

The excitation source signal provided by the test circuit board touches the end of the FPC/FFC gold finger welded with the thermal sheet through the test probe, and the excitation source signal flows through the circuit formed by the internal circuit of the thermal sheet through the FPC/FFC line. Detect the resistance value and voltage drop between the protection circuit between the PIN pin and GND of the internal related signal of the thermal chip IC, and judge whether there is welding in the corresponding line by switching the measurement of each PIN pin according to the set normal threshold value The quality is abnormal; after the test is completed, the test result is output through the test result output circuit;

Among them, after the thermal sheet is soldered to the software circuit board, the test probe can be used to touch the PIN end of the gold finger of the cable to test and determine whether there is a welding open circuit or short circuit abnormality when the thermal sheet is soldered to the cable, and the corresponding thermal sensor can be modified through the software. The chip's PIN pin test function is used to match different types of thermal chips.

According to a kind of test method based on thermal sheet welding open-short single-end needle planting provided by the present invention, when performing the short-circuit test of thermal sheet welding, test the unexpected short-circuit phenomenon on the thermal sheet to be tested, will expect The short circuit phenomenon forms a short circuit group. During the short circuit test, measure whether the resistance value between the short circuit and other groups is less than the standard value according to the recursive algorithm. If it is less than the group, there is a short circuit problem.

According to a test method based on thermal sheet welding open-short-circuit single-end needle planting provided by the present invention, when performing an open-circuit test of thermal sheet welding, the resistance value between the group and other PIN points is measured according to the recursive algorithm. It is greater than the standard value, if it is greater than, there is an open circuit problem.

According to a test method based on thermal sheet welding open-short-circuit single-ended pin implantation provided by the present invention, when measuring resistance, the excitation source circuit of the test circuit board sends a constant current source to the signal PIN of the thermal sheet to be tested. On the foot, the resistance value of the thermal film to be tested is calculated by measuring the voltage across the thermal film to be tested.

According to a test method based on thermal sheet welding open-short single-end needle planting provided by the present invention, the positive input terminal of the excitation source circuit of the test circuit board provides a test current, and the current flows through the sampling resistor and then flows to the excitation source switch The A channel of the switch then flows to the input terminal of the voltage follower circuit, flows through its output terminal to the A terminal of the pin switching circuit, and then flows to the PAD A pin welded by the thermal sheet through the test probe and the FFC/FPC connection cable.

According to the test method provided by the present invention based on thermal sheet welding open-short-circuit single-ended needle implantation, if the welding is not open, the test current flows to the internal circuit of the thermal sheet and then flows out from the PIN B pin, and then connects the wiring It flows out from the B terminal of the pin switching circuit, passes through the B channel of the excitation source switching switch, and then passes through the negative input terminal of the excitation source circuit to GND.

It can be seen that the test circuit board provided by the present invention has a hardware self-check function and a PIN pin finding function, and is simple and practical to maintain; The test probe touches the PIN end of the gold finger of the cable to test and determine whether there is any abnormal welding quality when the thermal film is soldered to the cable. The corresponding PIN test function of each type of thermal film can be used by modifying the corresponding PIN test function through software, which has strong versatility , fast test speed (single product test time <2 seconds), simple operation, ultra-low cost and easy popularization (test development board hardware cost <300RMB), etc., can realize low-cost and high-efficiency test functions.

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is a principle diagram of an embodiment of a test device based on a heat-sensitive sheet welding open-short-circuit single-end needle planting in the present invention.

FIG. 2 is a schematic diagram of a test circuit board in an embodiment of a test device based on thermal sheet welding open-short-circuit single-end needle planting in the present invention.

Fig. 3 is a schematic diagram for detecting whether the welding between the thermal sheet and the FPC/FFC cable is abnormal in an embodiment of a test device based on the thermal sheet welding open-short circuit single-end needle implantation in the present invention.

Fig. 4 is a test flow chart of an embodiment of a test method for single-end needle planting based on thermal sheet welding open-short circuit according to the present invention.

5 is a schematic diagram of an open-short circuit group in an embodiment of a test method for single-end needle implantation based on thermal sheet welding open-short circuit according to the present invention.

FIG. 6 is a schematic diagram of resistance testing in an embodiment of a test method based on thermal sheet welding open-short-circuit single-end needle planting in the present invention.

FIG. 7 is a schematic diagram of the first test for measuring clamping diodes in an embodiment of a test method based on thermal sheet welding open-short-circuit single-end needle implantation in the present invention.

FIG. 8 is a schematic diagram of a second test for measuring clamping diodes in an embodiment of a test method based on thermal sheet welding open-short-circuit single-end needle planting in the present invention.

FIG. 9 is a schematic diagram of the internal wiring of the heat-sensitive film IC in an embodiment of a test method based on heat-sensitive film welding open-short-circuit single-end needle implantation in the present invention.

FIG. 10 is a schematic diagram of a test current flow circuit in an embodiment of a test method based on thermal sheet welding open-short-circuit single-end needle planting in the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the following will clearly and completely describe the technical solutions of the embodiments of the present invention in conjunction with the drawings of the embodiments of the present invention. Apparently, the described embodiments are some, not all, embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

An embodiment of a test device based on thermal sheet welding open-short-circuit single-end needle implantation

Referring to Fig. 1, a kind of test device based on thermal sheet welding open-short single-ended needle implantation involved in the present invention includes: test probes installed on test tooling, test circuit board, external signal input circuit, test result output Circuit, the test circuit board touches the end of the FPC/FFC gold finger welded with the thermal sheet through the test probe, and outputs the excitation source signal to it, and the excitation source signal flows through the circuit formed by the internal circuit of the thermal sheet through the FPC/FFC line , used to detect the resistance value and voltage drop of the protection circuit between the internal related signal PIN pin of the thermal chip IC and GND; after the test is completed, the test circuit board outputs the test result signal to the test result output circuit, and the test result output circuit Output test results.

As shown in Figure 2, the test circuit board includes MCU main control circuit, excitation source circuit, ADC data acquisition circuit, input and output IO control module, analog switch switching circuit and voltage follower circuit, and the excitation source circuit provides a regulated power supply for the test circuit board , the ADC data acquisition circuit is used to collect the real voltage signal of the measured target and feed it back to the MCU main control circuit. The MCU main control circuit is connected to the external signal input circuit through the input and output IO control module, and the analog switch switching circuit is through the pin switching circuit. It is connected with the test probe, and the voltage follower circuit is connected with the excitation source circuit.

The test tool is equipped with a test probe needle mold, and the test probe is placed in the test probe needle mold. When installing and testing, put the test product into the needle mold groove, and sense the product under test through the infrared sensor. After entering, trigger the cylinder to press down, and the magnetic induction switch installed on the side of the cylinder senses that the pressure is in place, and the test will start automatically.

In this embodiment, the external signal input circuit includes a switch button and an electromagnetic inductor, and the MCU main control circuit is respectively connected to the switch button and the electromagnetic inductor through an input and output IO control module.

In this embodiment, the test result output circuit includes an LCD display screen, a test result indicator light and an alarm unit, and the MCU main control circuit is connected to the LCD display screen, the test result indicator light and the alarm unit respectively.

Specifically, the test device of this embodiment is mainly composed of a test circuit board, DC24V power supply, switch buttons, related connecting cables/conductors, test probes and needle socket connecting lines, test result indicator lights (red and green indicator lights), LCD display Screen (12864), infrared sensor, electromagnetic sensor and buzzer (onboard).

Among them, the test board includes:

MCU main control circuit (model stm32f103ze): realize the main logic function control processing and result judgment output display, as well as collect data, process data, and output control signals;

ADC data acquisition circuit (IC model AD7190): mainly used to achieve high-precision, high-real-time acquisition of the real voltage feedback of the measured target, and send it back to the MCU for data processing and analysis;

Input and output IO control module and analog switch switching circuit (composed of CD4052, CH446 IC models): Due to the limited IO output capability of the MCU, it is impossible to output power that meets the requirements and remove the reverse-serial interference of external devices, and it is necessary to add power output and safety isolation;

Excitation source circuit (composed of lm31117 IC and resistor divider circuit): the main power supply circuit of the MCU, which mainly steps down and stabilizes the external voltage to 3.3V to ensure the normal operation of the MCU;

Voltage follower circuit (consisting of LM358 chip): to protect the output and acquisition of MCU from external interference.

An embodiment of a test method for single-end needle implantation based on thermal sheet welding open-short circuit

A test method based on thermal sheet welding open-short-circuit single-end needle implantation, which is applied to the above-mentioned test device based on thermal sheet welding open-short-circuit single-end needle implantation for testing, the method includes:

The excitation source signal provided by the test circuit board touches the end of the FPC/FFC gold finger welded with the thermal sheet through the test probe, and the excitation source signal flows through the circuit formed by the internal circuit of the thermal sheet through the FPC/FFC line. Detect the resistance value and voltage drop between the protection circuit between the PIN pin and GND of the internal related signal of the thermal chip IC, and judge whether there is welding in the corresponding line by switching the measurement of each PIN pin according to the set normal threshold value The quality is abnormal; after the test is completed, the test result is output through the test result output circuit.

As shown in Figure 3, you only need to put the test product into the needle mold groove on the test fixture, and the infrared sensor senses that the product is put in and triggers the cylinder to press down, and the magnetic sensor switch installed on the left side of the cylinder senses the press down When it is in place, the test will start automatically. After the test is completed, the result will be displayed on the LED display and red and green LED lights. The cylinder will automatically rise and wait for the next test to be triggered. This cycle is simple and practical.

Among them, after the thermal sheet is soldered to the software circuit board, the test probe can be used to touch the PIN end of the gold finger of the cable to test and determine whether there is a welding open circuit or short circuit abnormality when the thermal sheet is soldered to the cable, and the corresponding thermal sensor can be modified through the software. The chip's PIN pin test function is used to match different types of thermal chips.

During the short-circuit test of thermal sheet welding, the unexpected short-circuit phenomenon on the thermal sheet to be tested is tested, and the expected short-circuit phenomenon is formed into a short-circuit group, and the short-circuit and other groups are measured according to the recursive algorithm during the short-circuit test. Whether the resistance value between them is less than the standard value, if it is less than the group, there is a short circuit problem.

When performing the open circuit test of thermal sheet welding, measure whether the resistance value between the group and other PIN points is greater than the standard value according to the recursive algorithm, and if it is greater, there is an open circuit problem.

When measuring resistance, the excitation source circuit of the test circuit board sends a constant current source to the signal PIN pin of the thermal sheet to be tested, and the voltage of the thermal sheet to be tested is calculated by measuring the voltage at both ends of the thermal sheet to be tested. resistance.

In this embodiment, a test current is provided by the positive input terminal of the excitation source circuit of the test circuit board, and the current flows through the sampling resistor and flows to the A channel of the excitation source switching switch, and then flows to the input terminal of the voltage follower circuit, through which The output terminal flows to the A terminal of the pin switching circuit, and then flows to the PAD A pin welded by the thermal pad through the test probe and the FFC/FPC connection cable.

If the welding is not open, the test current flows to the internal circuit of the thermal sheet and then flows out from the PIN B pin, then flows out from the B terminal of the pin switching circuit after connecting the cable, and passes through the excitation source after passing through the B channel of the excitation source switching switch. Negative input of the circuit to GND.

Specifically, this embodiment provides a low-cost and easy-to-operate test method, including the test device based on the thermal sheet welding open-short-circuit single-end needle planting as described in the above-mentioned embodiment, and the relevant test constant current ( 1～5mA) or constant voltage (5V/3.3V/1.25V) is formed by touching the end of the FPC/FFC gold finger welded with the thermal sheet through the test probe, and flowing through the internal circuit of the thermal sheet through the FPC/FFC line The circuit, by detecting the resistance value and voltage drop between the protection circuits between the internal related signal PIN pins, the normal threshold value is set by the software, and the measurement of each PIN pin is switched by the algorithm to determine whether there is a welding open circuit or not in the relevant circuit. Abnormal short circuit. After the test is completed, the test result is finally output through the LCD display and LED (red and green) indicators, and the test result NG is output by the buzzer at a specific frequency to alert the user.

The test circuit board of the present invention has a hardware self-check function and a PIN pin search function, and is simple and practical to maintain; The PIN end of the gold finger of the cable can be tested to determine whether there is abnormal welding quality when the thermal film is soldered and wired. The corresponding PIN test function of each type of thermal film can be used by modifying the corresponding PIN foot test function, which has strong versatility and fast test speed. (Single product test time <2 seconds), simple operation, ultra-low cost and easy popularization (test development board hardware cost <300RMB), etc., can realize low-cost and high-efficiency test functions.

Further, as shown in Figure 4, check whether there is an open circuit, short circuit with tin, false soldering, or misalignment in the welding between the thermal sheet and the FPC/FFC cable.

The following test items, test methods and test specifications are obtained by analyzing the relevant specification data of the thermal sheet to be tested, as shown in Table (1):

Table 1)

OPEN/SHORT test principle: The short-circuit test of thermal sheet welding is to test the unexpected (Unexpected) short circuit phenomenon on the thermal sheet to be tested, and there are usually some expected (Expected) short circuits on the thermal sheet to be tested, such as The power supply terminal VH, GND or other adjacent signal PINs are in the same network and other components smaller than the short-circuit Threshold exist. Therefore, in the process of writing the single-chip software, the expected short circuit can be formed into a short circuit group. The short circuit test is to measure whether the resistance value between it and other groups is less than the standard value according to the recursive algorithm. If it is less than the group, there is a short circuit problem. The open circuit test refers to whether the resistance value between the group and other PIN points is greater than the standard according to the recursive algorithm. If it is larger, there is an open circuit problem; its function example is shown in Figure 5, open and short circuit group ("{}" indicates a short circuit group).

As shown in Figure 6, when measuring resistance, a constant current source is sent from the excitation source circuit of the test board to the signal PIN of the thermal sheet to be tested, and the voltage to be tested is calculated by measuring the voltage at both ends of the thermal sheet to be tested. The resistance value of the thermistor.

The constant current output by the excitation source circuit of the test board is I, the resistance of the thermal film to be tested is R _X , the voltage on the thermal film to be tested is V _RX , and the resistance value of the thermal film to be tested can be calculated by the following formula out, the calculation method is as formula (1):

As shown in Figure 7, the test principle of measuring the clamping diode: Most thermal chips will add a protection diode to the input/output PIN, the main purpose is to act as a voltage CLAMP, taking a CMOS device as an example.

Since the input terminal is a MOS gate, the gate is a "metal-SiO2" capacitor, where SiO2 is a thin film. If the voltage of the gate is too high, such as static electricity, it will generate a large electric field and break down the SiO2 film. The gate terminal is used as a voltage limiter, and a diode is added, but when the voltage of the PIN is too high, the diode is easy to burn (a large current flows through the diode), so a resistor is often connected in series with the gate terminal to limit the current to protect the diode. The gate of the MOS uses the RS protection diode, and the clamping diode TEST uses this diode characteristic to judge whether the PIN of the thermal sheet is open or not. The method is to generate a 1.25V voltage (according to the input value) in the control board and send it out. , and in order to prevent the load from short-circuiting, it is necessary to add a current limiter (1mA), and measure the load voltage in the control board at the same time (similar to the Vx method of measuring the resistance). Since the error of RS is large and varies with each brand, it is necessary to The measurement value of the clamp diode needs to take a large error (0.3<Vx<0.8V). This voltage source is a constant current type, and the voltage source is placed in the test board. At the same time, the method of measuring Vx is similar to measuring resistance. Therefore, the VRs value is measured by the ADC of the test board, Vx=1.25-VRs, as shown in FIG. 8 .

As shown in Figure 9, Figure 9 is the internal wiring diagram of the thermal chip IC. When testing the voltage drop, the test principle is to use the protection diode voltage drop between each signal PIN and GND inside the thermal chip IC. When the TEST PIN sends a signal of a 1.25V excitation source to the pin to be tested of the thermal chip to be tested, at this time, the other signal pins of the thermal chip IC will be connected to the ground through the TESTPIN on the FIXTURE, if the pin to be tested When the pin is OPEN, because there is no signal on TESTPIN, Vx cannot sense a large enough pressure. When the pin is connected, Vx can sense a ratio IC due to the voltage drop between the thermal chip signal and GND. The voltage is small when OPEN, so you can know whether there is OPEN on the IC pin according to this voltage.

As shown in Figure 10, the positive electrode of the excitation source circuit flows through the sampling resistor and then flows to the A channel of the excitation source switch (IC) and then flows to the IN terminal of the voltage follower chip, and flows to the A terminal of the PIN switch through the OUT terminal, and then passes through The test probe and the FFC/FPC connection cable flow to the thermal sheet and solder the PAD A pin. If there is no OPEN during welding, the current flows to the internal circuit of the thermal sheet and then flows out from the PIN B pin, and then switches the switch chip B from PIN after connecting the cable. Outflow through the B channel of the excitation source switch (IC) and finally through the excitation source IN- to GND;

It can be seen that the test circuit board provided by the present invention has a hardware self-check function and a PIN pin finding function, and is simple and practical to maintain; The test probe touches the PIN end of the gold finger of the cable to test and determine whether there is any abnormal welding quality when the thermal film is soldered to the cable. The corresponding PIN test function of each type of thermal film can be used by modifying the corresponding PIN test function through software, which has strong versatility , fast test speed (single product test time <2 seconds), simple operation, ultra-low cost and easy popularization (test development board hardware cost <300RMB), etc., can realize low-cost and high-efficiency test functions.

The above-mentioned embodiment is only a preferred embodiment of the present invention, and cannot be used to limit the protection scope of the present invention. Any insubstantial changes and substitutions made by those skilled in the art on the basis of the present invention belong to the scope of the present invention. Scope of protection claimed.

Claims (10)

1. A testing arrangement based on single-ended planting needle of thermal sensitive piece welding open circuit is characterized in that includes:

the test device comprises a test probe, a test circuit board, an external signal input circuit and a test result output circuit, wherein the test probe, the test circuit board, the external signal input circuit and the test result output circuit are arranged on a test tool, the test circuit board is contacted with one end of an FPC/FFC golden finger welded with a thermosensitive plate through the test probe, an excitation source signal is output to the test circuit board, and the excitation source signal flows through a loop formed by an internal circuit of the thermosensitive plate through an FPC/FFC circuit and is used for detecting the resistance value and voltage drop of a protection circuit between a PIN PIN and GND of an internal related signal of the thermosensitive plate IC; after the test is finished, the test circuit board outputs a test result signal to the test result output circuit, and the test result output circuit outputs a test result;

the test circuit board comprises an MCU main control circuit, an excitation source circuit, an ADC data acquisition circuit, an input/output IO control module, an analog switch switching circuit and a voltage follower circuit, wherein the excitation source circuit provides a voltage stabilizing power supply for the test circuit board, the ADC data acquisition circuit is used for acquiring a real voltage signal of a tested target and feeding back the real voltage signal to the MCU main control circuit, the MCU main control circuit is connected with an external signal input circuit through the input/output IO control module, the analog switch switching circuit is connected with a test probe through a pin switching circuit, and the voltage follower circuit is connected with the excitation source circuit.

2. The test device for welding open-circuit and short-circuit single-ended planting needles based on the thermosensitive sheet according to claim 1, wherein the test device comprises:

the test fixture is provided with a test probe needle die, the test probe is placed in the test probe needle die, when the test fixture is installed and tested, a test product is placed in a needle die groove, the infrared sensor senses that the tested product is placed in the test product and then triggers the cylinder to press down, and the magnetic sensing switch installed on one side of the cylinder senses that the test is started automatically when the magnetic sensing switch is arranged on one side of the cylinder to sense that the test probe is pressed down in place.

3. The test device for welding open-circuit and short-circuit single-ended planting needles based on the thermosensitive sheet according to claim 1, wherein the test device comprises:

the external signal input circuit comprises a switch key and an electromagnetic inductor, and the MCU main control circuit is respectively connected with the switch key and the electromagnetic inductor through the input/output IO control module.

4. The test device for welding open-circuit and short-circuit single-ended planting needles based on the thermosensitive sheet according to claim 1, wherein the test device comprises:

the MCU main control circuit is respectively connected with the LCD display screen, the test result indicator lamp and the alarm unit.

5. A testing method based on a thermal-sensitive-sheet-welded open-short single-ended needle implantation, which is characterized by being applied to the testing device based on the thermal-sensitive-sheet-welded open-short single-ended needle implantation according to any one of claims 1 to 4 for testing, and comprising the following steps:

providing an excitation source signal by a test circuit board, contacting one end of an FPC/FFC golden finger welded with a thermosensitive plate through a test probe, enabling the excitation source signal to flow through a loop formed by an internal circuit of the thermosensitive plate through an FPC/FFC circuit, detecting a resistance value and a voltage drop between a protection circuit between a PIN PIN and GND of a related signal in the thermosensitive plate IC, and judging whether the corresponding circuit has abnormal welding quality or not by switching the measurement of each PIN PIN according to a set normal threshold value; after the test is completed, outputting a test result through a test result output circuit;

after the software circuit board is welded on the heat-sensitive sheet, whether the welding open circuit or the short circuit abnormality exists when the heat-sensitive sheet is welded on the flat cable can be tested and judged by the test probe contacting with one end of the PIN finger of the flat cable, and the PIN foot test function of the corresponding heat-sensitive sheet can be modified by software to be matched with the heat-sensitive sheets of different types.

6. The test method for the open-circuit single-ended needle implantation based on the thermal-sensitive welding of the sheet according to claim 5, wherein the test method comprises the following steps:

and when the short circuit test of the welding of the thermal sensitive sheet is carried out, the unexpected short circuit phenomenon on the thermal sensitive sheet to be tested is tested, the expected short circuit phenomenon is formed into a short circuit group, whether the resistance value between the short circuit and other groups is smaller than the standard value is measured according to a recursion algorithm when the short circuit test is carried out, and if the resistance value is smaller than the standard value, the short circuit problem exists.

7. The test method for the open-circuit single-ended needle implantation based on the thermal-sensitive welding of the sheet according to claim 6, wherein the test method comprises the following steps:

and when an open circuit test of the thermal sensitive sheet welding is carried out, measuring whether the resistance value between the group and other PIN points is larger than a standard value according to a recursive algorithm, and if so, having the open circuit problem.

8. The test method for the open-circuit single-ended needle implantation based on the thermal-sensitive welding of the sheet according to claim 5, wherein the test method comprises the following steps:

when measuring the resistance, the excitation circuit of the test circuit board sends a constant current source to the signal PIN of the thermal sensitive sheet to be measured, and the resistance value of the thermal sensitive sheet to be measured is calculated by measuring the voltages at two ends of the thermal sensitive sheet to be measured.

9. The test method for the open-circuit single-ended needle implantation based on the thermal-sensitive welding of the sheet according to claim 5, wherein the test method comprises the following steps:

the positive input end of the excitation source circuit of the test circuit board provides a test current, the current flows to the A channel of the excitation source change-over switch after flowing through the sampling resistor, then flows to the input end of the voltage follower circuit, flows to the A end of the pin change-over circuit through the output end of the voltage follower circuit, and then flows to the PAD A pin welded on the thermosensitive plate through the test probe and the FFC/FPC connecting flat cable.

10. The test method for the open-circuit single-ended needle implantation based on the thermal-sensitive welding of the sheet according to claim 9, wherein the test method comprises the following steps:

if the welding is not open, the test current flows to the internal circuit of the thermal sensitive sheet and then flows out from the PIN B, then flows out from the end B of the PIN switching circuit after being connected with the flat cable, and passes through the negative electrode input end of the excitation source circuit to GND after passing through the channel B of the excitation source switching switch.

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