CN104914349B - A digital tube aging screening and detection device and its working method - Google Patents

Abstract

The invention discloses a nixie tube aging screening and detecting device and a working method thereof. The circuit board adopts the cascade expansion interface to connect the cascade expansion circuit board, can connect the cascade expansion circuit board according to requirements, can simultaneously detect a large number of LED nixie tubes with different models by changing the circuit, the socket model and the resistance value of the current-limiting resistor on the cascade expansion circuit board, and has higher detection efficiency. The circuit board of the invention adopts industrial chips, and can detect the LED nixie tube in high-temperature or low-temperature environment. The invention can download the compiled program through the JTAG interface, and can more conveniently and accurately detect the missing segment (a certain segment of the LED nixie tube is not bright) and the connecting segment (a certain segment of the LED nixie tube is short-circuited) and has more comprehensive detection content.

Description

A digital tube aging screening and detection device and its working method

technical field

The invention relates to a LED digital tube detection technology, in particular to a digital tube aging screening and detection device and a working method thereof.

Background technique

At present, there are many detection methods for LED digital tubes, mainly as follows:

1. Digital multimeter detection. Use the diode file and hFE file to detect the polarity, pin arrangement and luminescence of the LED digital tube. This method is time-consuming and labor-intensive, and the inspection effect is greatly affected by individual subjective factors.

2. Manual visual inspection. Make the LED digital tubes to be checked display numbers 0~8, and English letters A, b, C, d, E, F hexadecimal characters to judge whether the LED digital tubes can display normally. However, the display process takes a long time, which is not conducive to cost control, and the repeated execution of the same process is easy to make the operators slack off, neglecting the existing errors, and it is difficult to find the hidden faults of the LED digital tubes.

3. The existing detection devices and methods are all detected at normal temperature, and the LED digital tubes that need to be used in a specific environment (high temperature, low temperature, etc.) cannot be detected and screened before use. In addition, the number of tests is limited, which is not suitable for large-scale testing requirements.

At present, technologies related to digital tube detection include: "Seven-segment digital tube detection method" disclosed in Chinese patent CN102213744A, "A kind of LED digital tube detection device and method" disclosed in Chinese patent CN103048583A and "A kind of LED digital tube detection method" disclosed in Chinese patent CN102194392A LED digital tube quality inspection method".

The central processing module in the LED digital tube detection device disclosed in Chinese patent CN103048583A simultaneously outputs detection levels of the same polarity to each segment selection end of the LED digital tube under test and the drive detection module, and the drive detection module is driven by a constant current source Drive the tested LED digital tube to work, the central processing module judges the polarity, qualification and pin position insertion and placement of the tested LED digital tube, and drives the detection result display module to display the corresponding detection result information in real time according to the judgment result.

The existing LED digital tube detection device and method, on the one hand, have a small number of detections and low detection efficiency, which cannot meet the detection requirements of large quantities, and are prone to misjudgment and misjudgment due to the repeated operation of the same action by the detection personnel for a long time; on the other hand, , It is difficult to identify the detection of missing segments (a certain segment of the LED digital tube is not bright) and continuous segments (a certain segment of the LED digital tube is short-circuited), as well as the brightness of the LED digital tube and the color difference between segments, and the quality defects of the LED digital tube cannot be completely ruled out .

Furthermore, none of the existing detection devices and methods can detect and screen the resistance and lifespan of LED digital tubes in high-temperature or low-temperature environments.

Contents of the invention

In order to solve the above-mentioned problems existing in the prior art, the present invention will design a digital tube that can improve the detection efficiency, improve the detection content, reduce the detection cost, and solve the problem of affecting the service life of the LED digital tube and being difficult to detect in a high temperature or low temperature environment. Aging screening and detection device and working method thereof.

In order to achieve the above object, the technical solution of the present invention is as follows: a digital tube aging screening and detection device, including a main circuit board and several cascaded expansion circuit boards, the main circuit board and several cascade expansion circuit boards pass through Two-way cables are connected in series, and the main circuit board is located in the middle of the series circuit.

The main circuit board includes a power supply module, a central processing module, a drive module, a cascade expansion interface L, a cascade expansion interface R, and a measured LED digital tube socket; The module, the cascade expansion interface L and the cascade expansion interface R are connected, the drive module is connected to the LED digital tube socket under test, and the drive module is also connected to the power supply module to obtain power supply. The external power supply is also the power module and the cascade expansion interface. L and the cascade expansion interface R provide the required voltage; the cascade expansion interface can transmit the control detection capability of the central processing module of the main circuit board and the external voltage of the power supply module to the cascade expansion circuit board.

The cascade expansion circuit board includes a power supply module, a drive module, a cascade expansion interface L, a cascade expansion interface R and a tested LED digital tube socket, and the power supply module is connected to the drive module and the cascade expansion interface respectively. L is connected to the cascade expansion interface R, and the drive module is also connected to the cascade expansion interface L, the cascade expansion interface R and the tested LED digital tube socket respectively; the cascade expansion interface L and the cascade expansion interface R is respectively connected to the main circuit board and the cascading expansion interfaces of other cascading expansion circuit boards.

Described central processing module comprises JTAG interface CN2, electric capacity C1, electric capacity C8, electric capacity C9, CPU U2, light emitting diode D2, light emitting diode D3, resistance R3 and resistance R4; Described electric capacity C1, electric capacity C8 and electric capacity C9 The positive poles of the resistors are respectively connected to the voltage output terminals of the power supply module, and the negative poles are respectively grounded; the first terminal of the resistor R3 is connected to the PD7 terminal of the central processing unit U2, the second terminal of the resistor R3 is connected to the positive pole of the light-emitting diode D2, and the first terminal of the resistor R4 It is connected to the voltage output terminal of the power supply module, the second terminal of the resistor R4 is connected to the positive pole of the light-emitting diode D3, the negative pole of the light-emitting diode D2 and the negative pole of the light-emitting diode D3 are commonly grounded; the first power supply terminal VCC1 of the central processing unit U2, the second The second power supply terminal VCC2 and the third power supply terminal VCC3 are connected to the voltage output terminal of the power supply module. The first ground terminal GND1, the second ground terminal GND2 and the third ground terminal GND3 of the central processing unit U2 are all grounded.

The power supply module includes an electrolytic capacitor C2, a voltage regulator U1, an inductor L1, a diode D1, an electrolytic capacitor C3, a capacitor C5, a resistor R1 and a resistor R2; the input terminal IN of the voltage regulator U1 and the positive pole of the electrolytic capacitor C2 are in common Connect and connect to the power interface, the power interface is connected to a DC power supply of 8 ~ 30V; the first end of the inductor L1 and the cathode of the diode D1 are connected to the output terminal OUT of the voltage regulator U1, the second end of the inductor L1 and the resistor R1 The first end, the positive pole of the electrolytic capacitor C3 and the positive pole of the capacitor C5 are connected together, the second end of the resistor R1 is connected with the FEEDBACK end of the regulator U1 and the first end of the resistor R2, the negative pole of the electrolytic capacitor C2, and the electrolytic capacitor C3 The negative pole of the capacitor C5, the second terminal of the resistor R2, the ground terminal GND of the voltage regulator U1 and the ON/OFF terminal of the voltage regulator U1 are commonly grounded.

Described driving module is made up of segment selection driver U3, segment selection driver U4 and bit selection driver U5; in the main circuit board, the input terminals of segment selection driver U3 and segment selection driver U4 are connected with the input and output terminals PA0～ PA6 is connected, and connected with the cascade expansion interface L and the cascade expansion interface R, and the 8 output terminals of the segment selection drive U3 pass through the current limiting resistor R1_1, the current limiting resistor R1_2, the current limiting resistor R2_1, the current limiting resistor R2_2, the current limiting resistor Current limiting resistor R3_1, current limiting resistor R3_2, current limiting resistor R4_1, current limiting resistor R4_2 and pin 1, pin 2, pin 4, pin 5, pin 7, lead Pin 10 is connected to pin 11, and the 8 output ends of segment selection drive U4 pass through current limiting resistor R5_1, current limiting resistor R5_2, current limiting resistor R6_1, current limiting resistor R6_2, current limiting resistor R7_1, current limiting resistor R7_2, current limiting resistor R7_1, current limiting resistor R7_2, current limiting resistor The current resistance R8_1 and the current limiting resistance R8_2 are connected to the pins 1, 2, 4, 5, 7, 10 and 11 of the LED digital tube sockets JP5~JP8 under test; The input terminals of drive U5 are respectively connected with the input and output terminals PC0-PC7 of the central processing unit U2, and connected with the cascade expansion interface L and the cascade expansion interface R, and the output terminals A0-A3 of the bit selection drive U5 are connected with the LEDs under test respectively. The pins 12, 9, 8 and 6 of the digital tube sockets JP1, JP3, JP5, and JP7 are connected, and the output terminals A4~A7 of the bit selection drive U5 are respectively connected to the tested LED digital tube sockets JP2, JP4, Pin 12, pin 9, pin 8, and pin 6 of JP6 and JP8 are connected; the tested LED digital tube sockets JP1~JP8 are 8 4-digit 7-segment common-cathode LED digital tube sockets. 1. Pin 2, pin 4, pin 5, pin 7, pin 10, and pin 11 are respectively connected to segment selection pin 1, segment selection pin 2, and segment selection pin 4 of the LED digital tube under test , Segment selection pin 5, Segment selection pin 7, Segment selection pin 10 and Segment selection pin 11, the pins 6, 8, 9 and 12 are respectively connected to the bits of the LED digital tube to be tested. Select pin 6, bit select pin 8, bit select pin 9 and bit select pin 12.

Central processing unit U2 described in the present invention is the single-chip microcomputer that model is ATmega162, and voltage regulator U1 is the voltage regulating and stabilizing chip that model is LM2576, and segment selection driver U3 and segment selection driver U4 are all the driver chips that model is 74HC245, bit The optional driver U5 is a driver chip with a model number of ULN2803.

A working method of a digital tube aging screening and detection device, comprising the following steps:

Step 1: Write the written LED digital tube lighting program into the central processing unit U2 through the JTAG interface CN2;

Step 2: Connect an appropriate number of cascade expansion circuit boards according to the detection requirements, and insert the LED digital tube to be tested into the main circuit board and the LED digital tube socket of the cascade expansion circuit board to form the LED digital tube circuit board to be tested ;

Step 3: Connect the DC power supply to the power supply module of the main circuit board, turn on the power supply, the power supply module provides power to the central processing unit U2, the segment selection driver U3 and the segment selection driver U4, and the output terminal voltage VCC of the power supply module The size is controlled by changing the resistance value of resistor R1 and resistor R2;

Step 4: The central processing unit U2 controls the LED digital tube to be tested to light up through the segment selection driver U3, segment selection driver U4 and bit selection driver U5, and the tester puts the tested LED digital tube circuit board into the required temperature environment according to the requirements For testing, the test time can be flexibly set according to the needs of use;

Step 5: After the test time is over, the inspectors visually observe and inspect the LED digital tube under test, and control it by pre-writing the display mode of the central processing module during the test. The display mode includes full brightness and sequential lighting , rotating circles and segments light up, and inspectors judge the fault by observing the lighting conditions of the tested LED digital tube in various display modes. If a certain segment is not on when it should be on, it means that there is a fault in this segment; If there is chromatic aberration, there is a fault that needs to be eliminated in this section.

Compared with the prior art, the present invention has the following beneficial effects:

1. Since the circuit board of the present invention adopts the cascading expansion interface to connect the cascading expansion circuit board, multiple cascading expansion circuit boards can be connected as required. The size can detect LED digital tubes of different sizes, different luminescence, and different polarities. It can meet the needs of detecting a large number of LED digital tubes of different types at the same time, and the detection efficiency is relatively high.

2. Since the present invention can download the lighting program written by oneself through the JTAG interface, the detected LED digital tube lighting mode is not single and fixed, and the detection of each segment and position of the LED digital tube is more comprehensive, especially for missing segments. (A certain segment of the LED digital tube is not bright) and the detection of continuous segments (a certain segment of the LED digital tube is short-circuited) is more convenient and accurate, and the detection content is more comprehensive.

3. Since the circuit structure of the present invention is simple, the size of the circuit board is small, and it does not affect the number and effect of the detection, the detection time can be set freely during the detection, and the detection personnel do not need to follow up and observe the whole process during the detection process, and can be directly observed after the detection After receiving the test results, LED digital tubes with color difference or brightness difference defects can be quickly screened out, and the test cost is relatively low.

4. Since the present invention can freely set the detection time during the detection process, for users who need to use the LED digital tube for a long time, it is obvious that a short-term detection before use cannot meet the requirements. There is no need for inspection personnel to follow up in real time, and the lighting time can be set at will; the inventive device has strong adaptability, and all use industrial-grade chips, which can detect LED digital tubes in specific high or low temperature environments to screen out which are not suitable for later use The product.

5. In order to conduct batch detection of LED digital tubes, a cascading expansion interface (J_Left and J_Right) is provided on both sides of the main circuit board, which is convenient for connecting the cascading expansion circuit board and testing more LED digital tubes. The external power supply supplies power to the power supply module and the cascading expansion interfaces on both sides at the same time. The cascading expansion interface transmits the voltage to each cascading expansion circuit board, and is converted to the voltage required by the drive module through the power supply module on the cascading expansion circuit board. , when the power of each detection board is the same, the circuit loss can be minimized.

Description of drawings

Fig. 1 is a structural diagram of the main circuit board module of the present invention.

Fig. 2 is a structural diagram of the cascade expansion circuit board module of the present invention.

Fig. 3 is a cascaded connection diagram of an expansion circuit that can be realized in the present invention.

Fig. 4 is a power supply circuit diagram of the present invention.

Fig. 5 is a 4-digit seven-segment common-cathode LED digital tube of the present invention.

Fig. 6 is a schematic circuit diagram of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

In the embodiment of the present invention, by adopting the LED digital tube aging screening and detection device including a central processing module, a driving module, and a power supply module, the power supply module and the central processing unit cooperate with the driving module to continuously and variously monitor the LED digital tubes under test. As well as the detection under specific environments (high temperature, low temperature, etc.), the circuit is simple and the cost is low, and the detection personnel can obtain the detection results very intuitively after the detection is completed. In addition, through the cascading expansion interface, multiple cascading expansion circuit boards can be connected, and the LED digital tubes can be detected in batches, which improves the detection efficiency. The circuit board of the present invention selects industrial-grade chips and components to meet the detection and use requirements in specific environments (high temperature, low temperature, etc.).

Fig. 1 shows the structure diagram of the main circuit board module of the LED digital tube detection device provided by the embodiment of the present invention, which is described in detail as follows:

The module structure diagram of the main circuit board of the LED digital tube detection device includes: a central processing module, a power supply module, a drive module, a socket of the LED digital tube to be tested, and a cascade expansion interface and other modules.

The central processing module is connected with the drive module, the power supply module and the cascade expansion interface, the drive module is connected with the LED digital tube socket under test, and the drive module is also connected with the power supply module to obtain power supply.

In order to carry out batch detection of LED digital tubes, a cascading expansion interface (J_Left and J_Right) is provided on both sides of the main circuit board to facilitate the connection of cascading expansion circuit boards to detect more LED digital tubes. The external power supply supplies power to the power supply module and the cascading expansion interfaces on both sides at the same time.

FIG. 2 is a structural diagram of the cascaded expansion circuit board module of the present invention. In practical applications, in order to detect different models and types of LED digital tubes, inspectors can change the circuit on the cascaded expansion circuit board, the type of LED digital tube socket and the resistance value of the current limiting resistor to complete the detection, and a large number of LED digital tubes need to be tested When connecting to the main circuit board, select an appropriate number of cascaded expansion circuit boards and connect them to the main circuit board. The cascade expansion board obtains the control detection capability of the central processing module and the external voltage of the power supply module from the main board or the cascade expansion board near the main board through the cascade expansion interface on one side, and the cascade expansion interface from the other side is Adjacent cascading expansion boards transmit the control and detection capabilities of the central processing module and the external voltage of the power supply module, so as to ensure that each cascading expansion circuit board normally implements detection work. As long as the main board does not solder the central processing unit U2 to the cascading expansion circuit board.

Figure 3 shows the cascade connection diagram of the expansion circuit board. The cascading expansion interface transmits the voltage to each cascading expansion circuit board, which is converted into the voltage required by the drive module through the power supply module on the cascading expansion circuit board. When the power of each detection board is the same, it can minimize the circuit loss. The invention not only can detect various types of LED digital tubes, but also realizes batch detection, improves detection efficiency and reduces detection cost.

The power supply module shown in Figure 4 includes:

Electrolytic capacitor C2, voltage regulator U1, inductor L1, diode D1, electrolytic capacitor C3, capacitor C5, resistor R1, resistor R2. The power supply interface can be connected to 8-30V DC power supply, and it is connected with the input terminal IN of the voltage regulator U1 and the positive pole of the electrolytic capacitor C2, and the first end of the inductor L1 is connected with the negative pole of the diode D1 to the output of the voltage regulator U1 terminal OUT, the second terminal of the inductor L1 is connected with the first terminal of the resistor R1, the positive pole of the electrolytic capacitor C3, and the positive pole of the capacitor C5, and the second terminal of the resistor R1 is connected with the FEEDBACK terminal of the regulator U1 and the first terminal of the resistor R2 The negative poles of the electrolytic capacitor C2, the negative poles of the electrolytic capacitor C3, the negative poles of the capacitor C5, the second terminal of the resistor R2, the ground terminal GND and the ON/OFF terminal of the regulator U1 are commonly grounded. The magnitude of the voltage VCC at the voltage output terminal can be controlled by the resistance values of the resistors R1 and R2. Wherein, the voltage regulator U1 may be a voltage regulating and stabilizing chip with a model number of LM2576.

Fig. 5 is a 4-digit seven-segment common-cathode LED digital tube involved in an embodiment of the present invention.

In the embodiment of the present invention, 8 4-bit 7-segment common-cathode LED digital tubes are detected, a, b, c, d, e, f, g are the segment selection pins of the tested LED digital tubes, and the The segment drivers are connected to U3 and U4, and S1, S2, S3, and S4 are the bit selection pins of the LED digital tube to be tested, which are connected to the bit selection driver U5. In the present invention, the LED digital tube to be tested adopts a dynamic display mode to light up.

FIG. 6 is a schematic circuit diagram of an embodiment of the present invention.

In the embodiment, the pre-written LED digital tube lighting program is written into the central processing unit U2 through the JTAG interface, the cascaded expansion circuit board is connected according to the detection requirements, and the LED digital tube to be tested is inserted into the soldered socket. Connect the DC power supply to the power supply module of the main circuit board and turn on the power supply. The output voltage VCC of the power supply module can be controlled by the resistance value of the resistor R1 and the resistor R2. The input DC power supply voltage range of the present invention is 8- 30V, the output voltage VCC of the power supply module is 3.48V, and provides 3.48V voltage to the central processing unit U2, driver chips U3, U4, and the central processor is connected to the driver chips U3, U4, U5 to light up the LED digital tubes to be detected. to test. Testers put the tested LED digital tube circuit board into the required temperature environment for testing according to the requirements, and the test time can be flexibly set according to the needs of use. After the test time is over, the inspectors visually observe and inspect the LED digital tube under test, and control it by pre-writing the display mode of the central processing module during the detection. The segment lights up, and the inspector judges the fault by observing the lighting status of the LED digital tube under test in various display modes. If a certain segment is not on when it should be on, it means that there is a fault in this segment; If there is chromatic aberration, there is a fault that needs to be eliminated in this section.

In the embodiment of the present invention, by adopting detection devices including a central processing module, a driving module, and a power supply module, the central processing module cooperates with the driving module to perform continuous and changing lighting detection of the LED digital tube, and the circuit structure is simple and the production cost is low. , strong adaptability, can detect and age-screen LED digital tubes in specific environments (high temperature, low temperature, etc.) And LED digital tube socket model, current limiting resistor resistance size, can realize the batch detection of multi-type LED digital tubes, the detection method is simple and efficient, for missing segments (LED digital tubes are not bright) and continuous segments (LED digital tubes There is a short circuit in a certain section) and the detection of the brightness of the LED digital tube and the color difference between the segments is more convenient, and the detection results can be obtained intuitively, which can eliminate the quality defects of the LED digital tube to the greatest extent, and avoid the real-time follow-up of the inspectors The detection saves manpower and material resources, improves the detection efficiency, and solves the problems of low detection efficiency, high cost and inability to carry out special pre-use screening detection existing in the prior art.

The above is only a preferred embodiment of the present invention, the implementation of the present invention is not limited by the above embodiments, any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (3)

1. a kind of charactron burn-in screen and detection means, it is characterised in that：Including main circuit board and several cascade extension electricity Road plate, described main circuit board and several cascade expander boards are connected by bidirectional cable, and main circuit board is located at series electrical The centre on road；

Described main circuit board includes power supply supplying module, central processing module, drive module, cascade expansion interface L, cascade expansion Open up the digital pipe insert seats of interface R and tested LED；Described central processing module respectively with drive module, power supply supplying module, cascade Expansion interface L and cascade expansion interface R connections, drive module and tested LED number pipe insert seat are connected, drive module also with power supply Supplying module connection is to obtain power supply supply, and external power supply is simultaneously power module, cascades expansion interface L and cascade expansion interface Voltage needed for R is provided；Described cascade expansion interface transmits the control of main circuit board central processing module to cascade expander board The external voltage of system detection signal and power supply supplying module；

Described cascade expander board includes power supply supplying module, drive module, cascade expansion interface L, cascade expansion interface R With the digital pipe insert seats of tested LED, described power supply supplying module extends with drive module, cascade expansion interface L and cascade respectively Interface R connections, described drive module is also inserted with cascade expansion interface L, cascade expansion interface R and tested LED charactrons respectively Seat connection；Described cascade expansion interface L and cascade expansion interface R respectively with main circuit board and other cascade expander boards Cascade expansion interface connection；

Described central processing module includes jtag interface CN2, electric capacity C1, electric capacity C8, electric capacity C9, central processing unit U2, luminous Diode D2, light emitting diode D3, resistance R3 and resistance R4；Described electric capacity C1, electric capacity C8 and electric capacity C9 positive pole connect respectively The voltage output end of power supply supplying module, negative pole is grounded respectively；Resistance R3 the first termination central processing unit U2 PD7 ends, electricity Hinder R3 the second termination light emitting diode D2 positive pole, resistance R4 first end and the voltage output end phase of power supply supplying module Connect, resistance R4 the second termination light emitting diode D3 positive pole, light emitting diode D2 negative pole and light emitting diode D3 negative pole Common ground；Central processing unit U2 the first power end VCC1, second source end VCC2 and the 3rd power end VCC3 is connected to electricity altogether The voltage output end of source supplying module, central processing unit U2 the first earth terminal GND1, the second earth terminal GND2 and the 3rd ground connection End GND3 is grounded；

Described power supply supplying module includes electrochemical capacitor C2, voltage-stablizer U1, inductance L1, diode D1, electrochemical capacitor C3, electric capacity C5, resistance R1 and resistance R2；Voltage-stablizer U1 input IN and electrochemical capacitor C2 positive pole connect and are connected with power interface altogether, electricity Source interface connects 8~30V dc source；Inductance L1 first end is connected to voltage-stablizer U1 output end with diode D1 negative pole altogether OUT, inductance L1 the second end and resistance R1 first end, electrochemical capacitor C3 positive pole and electric capacity C5 positive pole connect altogether, resistance R1 The second end connect with voltage-stablizer U1 FEEDBACK ends and resistance R2 first end, electrochemical capacitor C2 negative pole, electrochemical capacitor C3 negative pole, electric capacity C5 negative pole, resistance R2 the second end, voltage-stablizer U1 earth terminal GND and voltage-stablizer U1 ON/OFF ends Common ground；

Described drive module is made up of section choosing driving U3, section choosing driving U4 and position choosing driving U5；In main circuit board, section choosing driving U3 and section choosing driving U4 input are connected with central processing unit U2 input/output terminal PA0~PA6, and with cascading expansion interface L with cascade expansion interface R be connected, section choosing drive U3 8 output ends respectively by current-limiting resistance R1_1, current-limiting resistance R1_2, Current-limiting resistance R2_1, current-limiting resistance R2_2, current-limiting resistance R3_1, current-limiting resistance R3_2, current-limiting resistance R4_1, current-limiting resistance R4_2 Connect with the digital pipe insert seat JP1~JP4 of tested LED pin 1, pin 2, pin 4, pin 5, pin 7, pin 10 and pin 11 Connect, section choosing driving U4 8 output ends pass through current-limiting resistance R5_1, current-limiting resistance R5_2, current-limiting resistance R6_1, current limliting electricity respectively R6_2, current-limiting resistance R7_1, current-limiting resistance R7_2, current-limiting resistance R8_1 and current-limiting resistance R8_2 is hindered to insert with tested LED charactrons Seat JP5~JP8 pin 1, pin 2, pin 4, pin 5, pin 7, pin 10 and pin 11 is connected；Position choosing driving U5 input End is connected with central processing unit U2 input/output terminal PC0~PC7 respectively, and with cascading expansion interface L and cascade expansion interface R It is connected, position choosing driving U5 0~A3 of output terminals A pin 12 respectively with tested LED digital pipe insert seat JP1, JP3, JP5, JP7, Pin 9, pin 8, pin 6 are connected, position choosing driving U5 4~A7 of output terminals A respectively with the digital pipe insert seat JP2 of tested LED, JP4, JP6, JP8 pin 12, pin 9, pin 8, pin 6 are connected；Tested digital pipe insert seat JP1~JP8 of LED are 847 sections common Its pin 1, pin 2, pin 4, pin 5, pin 7, pin 10, pin 11 are distinguished in negative electrode LED number pipe insert seats, detection process The section of the tested LED charactrons of connection selects pin 1, section to select pin 2, section to select pin 4, section to select pin 5, section to select pin 7, section to select pin 10 and section select pin 11, pin 6, position are selected in the position that its pin 6, pin 8, pin 9, pin 12 connect tested LED charactrons respectively Pin 8, position is selected to select pin 9 and position to select pin 12.

2. a kind of charactron burn-in screen according to claim 1 and detection means, it is characterised in that：Described centre Reason device U2 is model ATmega162 single-chip microcomputer, and voltage-stablizer U1 is model LM2576 voltage-regulation voltage-stabilization chip, section choosing driving U3 and section choosing driving U4 are model 74HC245 driving chips, and position choosing driving U5 is model ULN2803 driving core Piece.

3. a kind of charactron burn-in screen as claimed in claim 1 and the method for work of detection means, it is characterised in that：Including Following steps：

The first step：The LED charactrons write are lighted by program by jtag interface CN2 and write central processing unit U2；

Second step：An appropriate number of cascade expander board is connected according to detection demand, LED charactrons to be measured are inserted in main electricity On the digital pipe insert seats of LED of road plate and cascade expander board, tested LED charactron circuit boards are constituted；

3rd step：Dc source is accessed into main circuit board power supply supplying module, switched on power, power supply supplying module is handled to center Device U2, section choosing driving U3 and section choosing driving U4 provide power supply, and the output end voltage VCC of power supply supplying module size is by changing Resistance R1 and resistance R2 resistance are controlled；

4th step：Central processing unit U2 sections choosing driving U3, section choosing driving U4 and the tested LED charactrons of position choosing driving U5 controls Light, tested LED charactrons circuit board is put into requires to be detected in temperature environment as desired by tester, the testing time Flexibly set according to using needs；

5th step：After testing time terminates, testing staff intuitively carries out observation detection to tested LED charactrons, leads to during detection Cross and be previously written the display mode of central processing module and be controlled, described display mode includes all light, lights, turn-takes successively Lighted with segmentation, testing staff lights situation failure judgement by the tested LED charactrons of observation under multiple display modes； If this lights but and does not have bright certain section, illustrate that the section has scarce segment fault；When segmentation is lighted, if two sections light simultaneously, then say The bright Duan Youlian segment faults；If certain section of brightness is relatively low or has aberration, the failure of this section of exclusion in need.