CN103617773B - A kind of exoelectron test macro of media protection membrane material and method - Google Patents

Abstract

A method for testing escaped electrons of a dielectric protective film material according to the present invention includes at least one cycle T for testing, and the cycle T includes the following successive voltage application cycles: 1) excitation cycle T _s , 2 ) Waiting period T _w , 3) Test period T _R ; Detect and record the optical signal generated by the discharge process of the working gas in the display unit of the plasma display screen under test during the test period, and at the same time obtain the scanning electrode Y and the maintenance time when the optical signal is generated. The test voltage difference V _D between the electrodes X is calculated by the formula V _w = V _f - V _D to obtain the internal field voltage V _w in the display unit, and the number of escaped electrons in the display unit is calculated according to V _w , and the alignment is completed. A test of the outgoing electrons of dielectric protective film materials. The invention relates to an exoelectronic test system for a dielectric protective film material used for realizing the test method, comprising a drive circuit, a photomultiplier tube, an oscilloscope, a computer, a control circuit and a power supply circuit.

Description

Exhaust electron testing system and method for a dielectric protective film material

technical field

The invention relates to the technical field of using gas discharge to measure tiny electrons, in particular to a testing system and method for the escaped electrons of a dielectric protective film material.

Background technique

Dielectric protective film materials are widely used in space, military industry, image enhancement, measurement and other fields due to their high sputtering resistance, long life, and high secondary electron emission characteristics. Among them, the application of the dielectric protective film in the plasma display (PDP, Plasma Display Panel) is particularly important. PDP mainly uses ultraviolet light generated by gas discharge to excite phosphors to emit light to realize the display of characters and images. According to different driving voltages and display units, plasma displays are classified into DC and AC discharge types. At present, the AC plasma display mainly adopts the addressing and display separation (ADS, Address Display Separate) driving method of the three-electrode structure to realize full-color display. Because of its long life, high reliability and low manufacturing cost, it has become a plasma The three-electrode AC discharge type plasma display is called a plasma display (PDP) hereinafter.

In the prior art, as shown in FIG. 1 , a PDP is mainly composed of two parts, a front substrate 1 and a rear substrate 2 . On the inner surface of the front substrate 1, there are two parallel and coplanar composite electrodes, the sustain electrode X and the scan electrode Y. Each composite electrode is composed of a metal electrode and an indium tin oxide transparent electrode. There is also a transparent dielectric layer 3 sintered with low glass powder between the composite electrode of the front substrate 1 and the gas discharge space. The dielectric layer 3 plays the role of isolating the composite electrode and the discharge space, and suppressing the discharge current. There is a dielectric protective film 4 made of magnesium oxide (MgO) on the surface of the dielectric layer 3. The dielectric protective film 4 mainly protects the medium and electrodes from sputtering of discharge ions and prolongs the working life of the medium. Since the secondary electron emission coefficient on the surface of the dielectric protection film 4 is relatively high, it can provide a certain amount of escaped electrons. The dielectric protection film 4 also has the functions of lowering the operating voltage, shortening the discharge delay, and improving the working stability of the device. On the rear substrate 2 of the PDP, the address electrodes A, the dielectric layer 3 of the rear panel, the phosphor layer 6 and the barrier ribs 5 are sequentially distributed.

PDP sustain discharge is mainly carried out between the sustain electrodes X and scan electrodes Y arranged in rows extending along the horizontal direction of the front substrate 1, and the vacuum ultraviolet (VUV) generated by the discharge is absorbed by the phosphor layer 6 coated on the rear substrate and converted into visible light Transmitted from the front substrate, a display image is formed. The address electrodes A are distributed on the surface of the rear substrate 2 and arranged in columns extending along a vertical direction. The scan electrode Y, the sustain electrode X and the address electrode A form a two-dimensional matrix, and each intersection of the matrix forms a display unit (pixel), and the plasma display screen realizes normal image display through the discharge process of the display unit. The coplanar discharge structure of the sustain electrode X and the scan electrode Y increases the space for VUV radiation and the effective discharge area, has a high uniformity of the discharge gap, and can prevent the phosphor layer 6 from being directly bombarded by VUV. Therefore, the brightness uniformity of the display screen can be improved, and the luminous efficiency of the display screen can be improved.

As shown in Figure 2, the PDP mainly includes basic units such as a plasma display screen, a control circuit, a scan drive circuit, a sustain drive circuit, and an address waveform generation circuit. During normal operation of the PDP, the addressing waveform generation circuit provides a given voltage V _a to the addressing electrode A according to the control signal of the control circuit. The scan driving circuit supplies a given voltage V _y to the scan electrode Y. The sustain drive circuit supplies the sustain electrode X with a given voltage V _x .

As shown in Figure 3, a complete display period of the ADS driving method consists of 10 subfields SF1~SF10, and each subfield consists of a preparation period (including the normal reset process t1 or global reset process t2), an addressing period (addressing process t3) and maintenance period (maintenance process t4). In the ADS driving method, during the preparation period, the voltage applied on the sustain electrode X and the scan electrode Y makes the wall charge distribution in each discharge cell of the display uniform and reaches a consistent state. During the addressing period, the discharge cells that need to emit light and the discharge cells that do not emit light are mainly selected. The applied voltage waveform is applied to the scan electrode Y and the address electrode A of the discharge cell that needs to emit light in a certain order. In the sustain period, sustain pulses are alternately applied to the scan electrode Y and the sustain electrode X. A continuous gas discharge is generated in the space of the display unit participating in the addressing to excite the phosphor to emit light.

In the prior art, PDP needs to use a working gas with high Xe (xenon) content in order to improve the luminous efficiency, which increases the discharge time (Td) of the PDP using the ADS driving method, and the discharge statistical time (Ts) in the addressing process becomes longer . After the addressing time is increased, the maintenance time of the displayed image will be correspondingly reduced, which will directly affect the contrast and brightness of the displayed image. In severe cases, it will also cause inaccurate addressing and maintenance error discharge, which seriously hinders the display quality. Especially with the development of emerging display technologies such as 3D display and 4 times high definition, it is necessary to further reduce the PDP addressing time. To improve the addressing stability and reduce the addressing time, it is necessary to enhance the exoelectron emission performance of the dielectric protection film material, and study the dielectric protection film material with high exoelectron emission characteristics to reduce the addressing time of the PDP. Accurate measurement of outgoing electrons is an important content in the study of material properties of dielectric protective films. In addition, high exoelectron emission materials in the fields of space science and electronic measurement have also been paid more and more attention and become a research hotspot. At present, the exoelectronic testing process mainly adopts the direct testing method.

In the prior art, the PDP escaped electrons all adopt the direct test method as shown in Figure 4. In this test method, the scan electrode Y, address electrode A, and sustain electrode X of all display units of the plasma display are connected together, and then Apply a square wave on scan electrode Y and sustain electrode X, and test the current on address electrode A. Since the addressing electrode A itself does not participate in the discharge basically, the current formed by it can be regarded as the vacuum ultraviolet (VUV, Vacuumultraviolet) generated by the gas discharge between the sustain electrode X and the scan electrode Y to excite electrons generated on the dielectric protection film material emission. After the current is drawn from the addressing electrode A, the current testing device is used to test, and the test result is used as a current formed by the escaped electrons of the dielectric protection film material, so as to make a judgment on the emission of the escaped electrons.

In addition, the exo-electron test can also detect the exo-electron emission current by suppressing the secondary electron emission on the surface of the dielectric protective film material through the metal mesh plate, and promoting the dielectric protective film to generate a small exo-electron emission current. The core is also mainly The current generated by the outgoing electrons is tested and amplified for detection.

However, there are many deficiencies in the measurement of these leakage currents in the prior art. Taking a high-definition PDP as an example, its display unit is only 0.81×0.27mm ² . During the test, the current formed by the escaped electrons of each display unit is less than 2pA, even if most of the display units are connected together, the current formed by the escaped electrons of the overall circuit is only a few nA. This nA-level current test requires professional equipment, which is not only expensive, but also easily affected by the large current generated by the alternating maintenance discharge of the device itself, and the phenomenon of alternating current overload appears continuously; especially the escape current itself is very Small, but the environmental current noise is relatively large, the test data is easily obliterated by the environmental noise, and it is difficult to obtain accurate measurement values. In some patents, the method of connecting an external resistor with a large resistance to the addressing electrode A and measuring the escaped electron current through the voltage drop of the resistor will also affect the accuracy of the test result due to the accuracy of the resistor itself and the distributed capacitance.

The deviation of the test results of the existing direct test method for outgoing electrons will have a certain impact on the application of dielectric film protection materials. It is necessary to find a more accurate and practical test method to realize the precise measurement of the outgoing electrons of the display unit.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a test system and method for the escaped electrons of the dielectric protective film material, which can reduce the test cost, improve the accuracy of the test results, and realize the accurate measurement of the escaped electron emission performance of the dielectric protective film .

The present invention is achieved through the following technical solutions:

A method for testing the escaped electrons of a dielectric protective film material according to the present invention includes at least one cycle T for testing, and the cycle T includes the following voltage application cycles carried out continuously in sequence,

1) Excitation period T _s : Alternately apply an excitation voltage including at least one discharge period T _c on the sustain electrode X and scan electrode Y of the plasma display screen under test, and the working gas completes at least one discharge process within one discharge period T _c ; The excitation voltage is not less than the ignition voltage V _f required for the discharge of the working gas in the plasma display screen under test;

2) Waiting period _Tw ; After the excitation period _Ts ends, the applied voltage on the sustain electrode X and the scan electrode Y is placed on the waiting voltage, which is less than the ignition required for the discharge of the working gas in the plasma display screen under test Voltage V _f ; the waiting time is not greater than the existence time of the escaped electrons generated when the working gas is discharged;

3) The test period T _R ; after the waiting period T _w ends, a synchronously rising test voltage is applied to the sustain electrode X and the scan electrode Y respectively, and the test voltage difference V _d between the scan electrode Y and the sustain electrode X gradually increases And only one working gas discharge process is generated;

Detect and record the optical signal generated by the discharge process of the working gas in the display unit of the plasma display screen under test, and at the same time obtain the difference V _D between the test voltage between the scanning electrode Y and the sustaining electrode X when the optical signal is generated, by the formula V _w =V _f -V _D Calculate the internal field voltage V _w in the display unit, calculate the number of escaped electrons in the display unit according to V _w , and complete a test on the escaped electrons of the dielectric protection film material.

Preferably, the waveform of the excitation voltage is a combination of one or more of square wave, triangular wave, trapezoidal wave, multi-pulse wave, sine wave and exponential wave; the waveform of the test voltage is a ramp wave, exponential wave, triangular wave, trapezoidal wave One or more combinations of them.

Preferably, the waiting time is greater than 1 ms.

Preferably, the scan electrode Y and the sustain electrode in the plasma display screen under test are respectively short-circuited together to apply voltage successively, and the address electrode A is short-circuited together and grounded.

Preferably, through repeated tests of the same cycle T for multiple times, the corresponding multiple test voltage differences V _D are respectively obtained, and the average value is taken as the final test result of the test voltage difference V _D .

The present invention is a kind of exoelectronic test system for realizing the dielectric protective film material of test method described in the present invention, comprises drive circuit, photomultiplier tube, oscilloscope, computer, control circuit and power supply circuit; Described drive circuit comprises The scan drive circuit and the sustain drive circuit are used to provide the applied voltage; the scan drive circuit and the sustain drive circuit are respectively connected to the scan electrode Y and the sustain electrode X on the plasma display screen under test; the photomultiplier tube is arranged on the The image output side of the front panel of the display unit in the plasma display screen is used to detect the optical signal generated by the working gas discharge process in the display unit, and convert the optical signal into an electrical signal and input it to the oscilloscope; the oscilloscope also uses The applied voltage signal corresponding to the test is loaded on the scanning electrode Y and the sustaining electrode X; the computer is used to set the loading parameters of the applied voltage, and is used to receive one electrical signal and two applied voltage signals collected by the oscilloscope, and use The calculation and comparison output of signal data; the control circuit is used to convert the loading parameters output by the computer into switch signals, and output them to the drive circuit together with the generated switch control timing signals; the power supply circuit is used to drive The electrical and control circuits provide the required voltages.

Preferably, an optical auxiliary system is arranged between the photomultiplier tube and the front panel of the display unit, and the optical auxiliary system includes at least one set of eyepiece systems for focusing the detection range of the photomultiplier tube on the target display unit or multiple display units. in the display area of the target.

Further, filters are superimposed in the eyepiece system.

Preferably, the power supply circuit includes an adjustable voltage DC stabilized power supply.

Preferably, the scan drive circuit includes a square wave circuit, an up-ramp circuit and a down-ramp circuit for controlling the waveform of the voltage applied to the scan electrode Y, and the sustain drive circuit includes a circuit for controlling the waveform of the voltage applied to the sustain electrode X. Square wave circuit and ramp wave circuit.

Compared with the prior art, the fugitive electron testing method described in the present invention has the following beneficial technical effects:

1. By alternately applying the excitation voltage on the sustain electrode and the scan electrode during the excitation period, the working gas discharge between the sustain electrode and the scan electrode generates VUV, and then excites the dielectric protective film material to generate exoelectrons; including multiple The excitation voltage of the discharge cycle can continuously accumulate the number of escaped electrons through each discharge of the working gas, thereby greatly reducing the difficulty of testing the escaped electrons. At the same time, it can also adjust the number of discharge cycles to meet different tests. Demand, control the number of escaped electrons, precise control, wide application range.

2. Using the characteristic that the existence period of the wall charge attached to the surface of the dielectric protective film formed by the discharge of the working gas is much shorter than the existence period of the outgoing electrons, the waiting voltage lower than the ignition voltage is applied during the waiting period, so that the memory in the waiting period The wall charges in the display unit are gradually lost and the number is reduced; by adjusting the waiting time of the waiting period, the influence of the wall charges in the display unit on the test of extraneous electrons is minimized, which greatly increases the proportion of the space charges of the extraneous electrons in the working gas. , thereby eliminating the adverse effects of wall charges in the test results and ensuring the accuracy of the test results.

3. Through the control of the applied voltage, the discharge of the working gas of the display unit is realized, thereby generating a light signal, and the difference between the test voltage of the scanning electrode and the sustaining electrode is obtained by using the detection of the light signal and the position of the corresponding light signal, so that it can pass The difference between the fixed gas ignition voltage and the collected and calculated test voltage is used to obtain the voltage value of the internal electric field. Since the internal electric field after the waiting period is mainly formed by the escaped electrons, the number of escaped electrons can be obtained, and the test is simple and convenient; What is used in the invention is to judge the occurrence of the gas discharge process by collecting the optical signal generated by the extravasated electrons, and then obtain the electric field generated by the escaped electrons, calculate the number of escaped electrons, and realize the indirect measurement of the escaped electrons. The test avoids the impact of the instrument on the test accuracy in the direct test; and because the object of the direct test is the optical signal instead of the current signal, it overcomes the annihilation effect of the tiny current of the extravasated electrons by the environmental current noise, and realizes the accurate measurement of the extravasated electrons. It has strong practicability and high test accuracy, and can be well applied in the measurement of the escaped electrons of dielectric protective films of various materials in different environments.

Further, by limiting the excitation voltage, the operational difficulty of the test method is reduced, and at the same time, by limiting the test voltage waveform, it is convenient to meet the requirement that the test voltage rises synchronously and the difference between the test voltages increases, reducing calculation and The difficulty of operation improves the test efficiency.

Furthermore, by limiting the lower limit of the waiting time, a large amount of wall charge is guaranteed to be lost, so that the main charge in the display unit is the escaped charge, thereby better improving the accuracy of the test.

Further, during the test, the scanning electrodes are short-circuited, the sustain electrodes are short-circuited, and the addressing electrodes are short-circuited to ground, which ensures that the escaped electrons will not be affected by the external circuit during the test, and better improves the The accuracy of the test.

Further, through the algorithm of taking the average value after multiple measurements of the test voltage difference, the correctness of the calculated data is ensured, the randomness of the collected data is avoided, and the accuracy of the test is better improved.

The test system of the present invention realizes the output of the voltage applied to the scanning electrode and the sustaining electrode in different periods through the driving circuit, and uses the photomultiplier tube to realize the collection and conversion of the weak light signal emitted by the discharge of the working gas in the display unit, In order to accurately judge the occurrence of the gas discharge process, the test voltage applied on the scanning electrode and the sustaining electrode during the working gas discharge is collected synchronously through the oscilloscope; the computer is used to dynamically adjust the loading parameters corresponding to the applied voltage in real time to realize the control of the test process. Realize the logic sequence of loading parameters through the control circuit, obtain the switch control sequence signal, and realize the sequence control of the corresponding scanning drive circuit and maintenance drive circuit in the drive circuit; the system has strong versatility, low equipment cost, simple implementation, and no direct external communication Escaped electrons form a current test, thus avoiding the impact of equipment accuracy on test results, enhancing the accuracy and practicability of the escaped electrons test, and overcoming the influence of equipment current test range and load size on the test in the prior art.

Furthermore, the setting of the eyepiece system can improve the pertinence and accuracy of the test system for detecting the optical signal in the display unit, and ensure that the optical signal can be picked up normally without being obliterated by external signals, thereby reducing test errors.

Further, by using the optical filter superimposed in the eyepiece system, an optical filter of corresponding wavelength can be added in front of the optical system to filter the influence of ambient light on the test result, thereby improving the sensitivity of optical signal detection.

Furthermore, through the limitation of the circuit, the requirements of the control circuit and the drive circuit for high voltage and low voltage and the conversion between them are better met, and the normal and stable operation of the test system is guaranteed.

Further, by setting the scanning driving circuit and the sustaining driving circuit, the requirements for waveform control of the applied voltage during testing can be better met, the efficiency of testing can be improved, and the difficulty of operation can be reduced.

Description of drawings

FIG. 1 is a schematic diagram of a transverse cross-sectional structure of a display unit of a plasma display panel in the prior art.

FIG. 2 is a schematic diagram of the basic structure of a PDP in the prior art.

FIG. 3 is a time distribution diagram of sub-field composition in the PDP adopting the ADS driving method in the prior art.

FIG. 4 is a schematic diagram of a direct test method for PDP exodus electrons in the prior art.

FIG. 5 is a schematic diagram of a waveform of an applied voltage according to the present invention.

Fig. 6 is a structural block diagram of the testing system of the present invention.

7 is a block diagram of the drive circuit of the present invention; 7a is a block diagram of a scan drive circuit, and 7b is a block diagram of a sustain drive circuit.

FIG. 8 is a schematic diagram of the connection between the display unit and the test system according to the present invention.

FIG. 9 is a schematic diagram of the discharge voltage and discharge time of the display unit according to the present invention.

In the figure: 1 is the front substrate, 2 is the rear substrate, 3 is the dielectric layer, 4 is the dielectric protective film, 5 is the barrier wall, 6 is the phosphor layer, 7 is the visible light, 8 is the optical auxiliary system, X is the sustain electrode, Y A is a scan electrode, and A is an address electrode.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

A method for testing the escaped electrons of a dielectric protective film material according to the present invention, as shown in FIG. 5 , includes at least one cycle T for testing, and the cycle T includes the following successive voltage application cycles,

1) Excitation period T _s : Alternately apply an excitation voltage including at least one discharge period T _c on the sustain electrode X and scan electrode Y of the plasma display screen under test, and the working gas completes at least one discharge process within one discharge period T _c ; The excitation voltage is not less than the ignition voltage V _f required by the working gas discharge in the plasma display screen to be tested; thereby forming a VUV gas discharge for exciting the outgoing electrons between the sustain electrode X and the scan electrode Y.

2) Waiting period _Tw ; After the excitation period _Ts ends, the applied voltage on the sustain electrode X and the scan electrode Y is placed on the waiting voltage, which is less than the ignition required for the discharge of the working gas in the plasma display screen under test Voltage V _f ; the waiting time is not greater than the existence time of the escaped electrons generated during the discharge of the working gas; thereby reducing the surface wall charge of the dielectric protective film and enhancing the number of escaped electrons in the discharge space charge, the waiting voltage can be set to zero or one At a fixed level that will not cause discharge, in this preferred embodiment, as shown in FIG. 5 , the waiting voltage selection is set to zero as an example.

3) The test period T _R ; after the waiting period T _w ends, a synchronously rising test voltage is applied to the sustain electrode X and the scan electrode Y respectively, and the test voltage difference V _d between the scan electrode Y and the sustain electrode X gradually increases And only one working gas discharge process is generated; detect and record the optical signal generated by the working gas discharge process in the display unit of the plasma display screen under test, and at the same time obtain the test voltage between the scanning electrode Y and the sustaining electrode X when the optical signal is generated The difference V _D , the internal field voltage V _w in the display unit is calculated by the formula V _w = V _f - V _D , and the number of escaped electrons in the display unit is calculated according to V _w . of a test. The method realizes the measurement of the exoelectron in the discharge process in which the exoelectron participates, changes the current test in the prior art into a visible light test, and improves the accuracy of the test by detecting the corresponding applied voltage change.

The basic principle of the test method of the present invention is that, during the internal discharge process of the display unit, the ignition voltage V _f required by the gas discharge is the sum of the external voltage and the internal electric field V _W formed by the internal charges in the discharge space. The voltage V _f required for gas discharge is a certain value, and the applied voltage corresponds to the applied voltage at the time point of the VUV position corresponding to the actual discharge, that is, the voltage difference V _D of the applied voltage on the sustain electrode X and the scan electrode Y, and the display unit The internal field voltage V _W =V _f –V _D generated by the exoelectrons. Therefore, the difference V _D of the test voltage during the gas discharge process is calculated by the position of the VUV photon pulse generated by the working gas discharge in the test period and the test voltage applied to the scan electrode and the sustain electrode corresponding to the applied voltage, that is, the applied value of the corresponding luminous point Voltage, and then the voltage value of the internal electric field V _W can be calculated with the ignition voltage and the applied voltage. At this time, the internal electric field is mainly formed by the outgoing electrons. After obtaining the internal electric field V _W , the size of the outgoing electrons can be obtained to realize the measurement of the outgoing electrons.

The constitutional mechanism of the cycle period in the test method of the present invention is that the exoelectrons originate from the Auger effect in the re-nucleation process of electrons and holes, especially the Auger electron emission generated by the excitation of 147nm VUV photons to the band gap of the dielectric protective film, Therefore, the escaped electrons have a longer life, and the number is affected by the number of gas discharges. The more discharge times, the greater the number of escaped electrons. In the present invention, the number of VUV photon excitations can be adjusted by adjusting the number of discharge cycles T _C of the periodic discharge, thereby increasing effective Auger electron emission and increasing the number of outgoing electrons. Changing the time length of the waiting period can adjust the waiting time before the measurement of the outgoing electrons and wall charges before the test period and after the excitation period. Because the lifetime of the ions generated by the working gas circuit is very short, the wall charge will be lost as time goes on during the waiting period, while the life of the escaped electrons is longer. After the waiting process, the charge that can exist in the display unit is mainly escaped. electronics, thereby improving the accuracy of the measurement results. It avoids the problem that during the measurement process, due to the small number of escaping electrons, the current formed is very small and is obliterated by the environmental current noise. By measuring the internal electric field formed by the accumulation of escaping electrons inside the display unit, the external electric field is applied when the working gas is discharged. , and then measure the number of outgoing electrons.

Preferably, the waveform of the excitation voltage is a combination of one or more of square wave, triangular wave, trapezoidal wave, multi-pulse wave, sine wave and exponential wave; the waveform of the test voltage is a ramp wave. In this preferred embodiment, as As shown in Figure 5, the waveform of the excitation voltage is a square wave, and the waveform of the test voltage is a ramp wave.

Preferably, the waiting time is greater than 1 ms. After the waiting time passes, a large amount of wall charges will be lost, further increasing the proportion of escaping charges. When adopting the test method of the present invention, the scan electrode Y and the sustain electrode in the plasma display screen to be tested are respectively short-circuited together to apply a voltage successively, and the addressing electrode A is short-circuited together and grounded, so as to ensure that the external Yi Electronics will not be affected by external circuits, improving test accuracy.

Preferably, in order to ensure the correctness of the data, the corresponding multiple test voltage differences V _D are respectively obtained through repeated tests of the same cycle T, and the average value is taken as the final test result of the test voltage difference V _D .

A kind of escape electronic test system of the dielectric protective film material of the present invention, as shown in Figure 6, it comprises drive circuit, photomultiplier tube, oscilloscope, computer, control circuit and power supply circuit for realizing above-mentioned test method; The drive circuit includes a scan drive circuit and a sustain drive circuit for providing an applied voltage; the scan drive circuit and the sustain drive circuit are respectively connected to the scan electrode Y and the sustain electrode X on the plasma display screen to be tested; The photomultiplier tube is set on the image output side of the front panel of the display unit in the plasma display screen under test, and is used to detect the light signal generated by the working gas discharge process in the display unit, and convert the light signal into an electrical signal and input it to the oscilloscope The oscilloscope is also used to test the applied voltage signal corresponding to the scanning electrode Y and the sustain electrode X; the computer is used to set the loading parameters of the applied voltage, and is used to receive the electrical signal collected by the oscilloscope and two The circuit applies voltage signals, and is used for calculation and comparison output of signal data; the control circuit is used to convert the loading parameters output by the computer into switch signals, and output them to the drive circuit together with the generated switch control timing signals; The power supply circuit is used to provide the required voltage for the drive circuit and control circuit.

Among them, the computer is used to set the loading parameters such as the shape of the waveform of the applied voltage, the number of cycles, and the duration of the external electronic test. At the same time, the data of the discharge position and discharge voltage transmitted by the oscilloscope will be collected to form corresponding calculation results. Output in the form of a report, so as to obtain an evaluation report for the performance test of the dielectric protective film's escaped electron emission; the drive circuit uses the switch control sequence transmitted by the control circuit to maintain and scan the applied voltage of the corresponding waveform output by the two drive circuits respectively loaded on the sustain electrodes and scan electrodes of the display screen; the oscilloscope unit is used to test the three-way signals, two of which preferably use high-voltage probes to collect the waveforms of the applied voltages on the scan electrodes and sustain electrodes, and analyze the working status of the drive circuit. The other channel uses a photoelectric multiplier to collect the discharge of the display unit during the measurement period, and the data of the three channels are transmitted to the computer for analysis through the interface to form discharge position and scanning voltage data during discharge. The photomultiplier tube converts the weak light signal generated during the gas discharge process into an electrical signal to judge the occurrence of the gas discharge process, so as to accurately collect the test voltage difference between the sustain electrode X and the scan electrode Y during the discharge process. In the process of use, the cycle length of each discharge cycle _Tc of the excitation cycle, the time length of the rising edge and falling edge of the waveform, and the time parameters of the waiting cycle can be adjusted by the computer and the corresponding timing can be realized by the control circuit Control to achieve precise control of the start point and end point of the applied voltage waveform.

When the computer transmits the parameters related to voltage loading to the control circuit, that is, the transmission of the waveform control parameters, preferably in the form of a parameter table, including the switch state of each control signal, the duration of the corresponding state, and various periodic waveforms Cycle Time. The parameter table can dynamically modify each signal and its timing to ensure that the display screens with different process parameters can have suitable waveforms to achieve test accuracy and stability. The computer's control of the applied voltage can increase the number of cycles of the excitation cycle, prolong the time of the waiting cycle, adjust the waveform slope of the test cycle, realize the selection and combination of various waveforms such as square wave, exponential, and triangle, and increase the emission of exoelectrons. Quantity, to reduce the impact of wall charges on the test results. It meets the control requirements of the test method and can be performed in real time. After the computer interface parameters are modified, real-time modification can be carried out through the communication between the computer and the control circuit.

In this preferred embodiment, as shown in Figure 8, an optical auxiliary system is arranged between the photomultiplier tube and the front panel of the display unit, and the optical auxiliary system includes at least one set of eyepiece systems for making the detection range of the photomultiplier tube converge to In the target display unit or the target display area composed of multiple display units, the optical signal is focused, filtered and amplified by the optical auxiliary system 8 at the front end of the photomultiplier tube to form a millivolt level voltage signal for testing. Preferably, an optical filter is superimposed in the eyepiece system to reduce the influence of ambient light on the test result.

In this preferred embodiment, the power supply circuit adopts an adjustable DC stabilized power supply capable of providing low voltage and high voltage. The scanning driving circuit includes a square wave circuit for controlling the voltage waveform applied to the scanning electrode Y, an up ramp circuit and a down ramp circuit, and the sustain driving circuit includes a square wave circuit for controlling the voltage waveform applied to the sustain electrode X and ramp circuits.

Specifically, when using the test method and the test system described in the present invention to test the exoelectrons.

As shown in Figure 5, it is a cycle T of a test. During the excitation period T _s , the alternating excitation voltage applied to the sustain electrode X and the scan electrode Y causes the excitation discharge of the working gas in the display unit. The gas The discharge process will generate a large number of VUV photons, which provide energy and excite the electrons captured by the solid surface defects of the dielectric protective film to escape into the discharge space to form exoelectrons. At the same time, after the gas itself is ionized, it can also form wall charges attached to the surface of the dielectric protection film. During this process, the number of discharge periods T _c that are alternately applied periodically on the sustain electrode X and the scan electrode Y determines the number of wall charges generated by the gas discharge and the number of outgoing electrons. The more excitation voltage discharge cycle _Tc , the more escaped electrons, the easier the test, so it is necessary to dynamically adjust the discharge cycle _Tc according to the actual test situation. Specifically, the voltage amplitude V _S =200V is used for the excitation cycle, the single discharge cycle _Tc used is composed of a square wave with a duty cycle of 50%, the cycle is 20μs, and the number of discharge cycles _Tc is 50.

In the waiting period T _w stage, the waiting voltage is applied to the sustain electrode X and the scanning electrode Y, and the working gas will not discharge under the waiting voltage. Since the existence period of the wall charge is much shorter than the outgoing electrons, as the waiting time increases, The wall charges will gradually flow away, and the number will decrease, while the outgoing electrons will have a longer existence time through the continuous recombination-excitation process in the excitation period T _s , and their number will not change significantly. The content of escaped electrons in the test electrons is increased through the waiting period, and the accuracy of the test signal is enhanced. Specifically, in the waiting period, the waiting voltage on the scan electrode Y and the sustain electrode X are both set to 0V, and the whole waiting period time T _W =5 ms.

During the test period T _R phase, the sustain electrode X and the scan electrode Y are respectively applied with ramp test voltages of different shapes, wherein the amplitude of the test voltage applied to the scan electrode Y is V _S +V _R , and the amplitude of the test voltage applied to the sustain electrode X is The magnitude of the test voltage is V _S , and a photomultiplier is used to test the starting position and voltage magnitude of the discharge between the scan electrode Y and the sustain electrode X. By measuring the value of the test voltage difference, the number of outgoing electrons can be calculated; specifically, in the test period T _R , the test voltage applied by the scanning electrode Y rises vertically to the amplitude of V _S , and then gradually rises with a slope of 2V/μs to the voltage _VR , _VR =200V. After that, the voltage applied by the scan electrode Y drops vertically to the amplitude of V _S , and then drops to 0V with a slope of 1.6V/μs, and the test voltage applied by the sustain electrode X gradually rises to the voltage amplitude of V _S with a slope of 1.4V/μs , after the test voltage on the scan electrode Y and the sustain electrode X reaches the highest point amplitudes of V _S +VR and V _{S respectively} , the sustain electrode drops to 0V, and under the waveform of this test voltage, a test cycle T _R is completed testing process.

During the test, the test system used is shown in Figure 6. The computer can adapt to the test system for testing different dielectric protective film materials; Piezoelectric power supply; specifically, the control circuit is implemented by a logic control device with logic processing and interface communication capabilities, the output power device control signal is 14, and the minimum resolution of the timing of the generated signal is 25ns; the drive circuit is aimed at this preferred embodiment Specifically, the method and requirement setting, the structure is shown in FIG. 7 , the scan drive circuit includes: a square wave circuit, an up ramp circuit, and a down ramp circuit, and the sustain drive circuit includes a square wave circuit and a ramp circuit. The drive circuit can generate square waves and slope waves required for the applied voltage proposed in the embodiment of the present invention. The power devices included in the drive circuit are all rated at least 150A and 300V. In this preferred example, the rated values are 160A and 350V. High-speed IGBT or MOSFET switching tubes, in order to meet the needs of the actual waveform current, these power devices are used in parallel in some circuits. The waveform control of the entire applied voltage is generated by the control circuit, and the control circuit outputs a total of 14 logic timing signals, respectively controlling QerH, QerL, QsusH, QsusL, QrampH, QpassH, The switching control signals of power devices such as QrampL and QpassL, V _S =200V, V _setup =200V, and V _y =0V in Figures 5 and 7 are high-voltage direct currents, which are provided by the power circuit unit. In this embodiment, the entire cycle period T The waveform of the applied voltage is a combination of square wave and ramp wave.

During the test, the connection structure between the test system and the display unit of the plasma display screen under test is shown in Figure 8. The photomultiplier tube is directly applied to the front substrate 1 of the display unit by means of an optical auxiliary system 8, so that the photomultiplier tube can be tested to maintain The working gas discharge between the electrode X and the scanning electrode Y produces weak light, and converts the light signal into an electrical signal to form an electrical pulse signal higher than the ambient noise. The photomultiplier tube used in this preferred example can pick up nA-level dark current, has high irradiation sensitivity, can pick up the photons generated by the discharge in the display unit and amplify them to a millivolt level voltage signal and transmit it to the oscilloscope. The voltage signal can be recognized normally by the oscilloscope. In order to ensure that the VUV photon signal can be picked up normally and not be annihilated by external signals, a filter of corresponding wavelength can also be added to the superposition of the optical auxiliary system to filter the influence of ambient light on the test results and improve the sensitivity of the signal.

The corresponding relationship of the data obtained after the test is shown in Figure 9. After the test period _TR starts, the test voltage applied on the scan electrode Y rises vertically to the amplitude of VS, and then the test voltage _applied on the start and sustain electrodes has different slopes. The ramp continues to rise synchronously. At this time, the voltage difference between the voltage applied to the scan electrode and the sustain electrode increases gradually, and the sum of the charge V _W accumulated by the exoelectrons inside the display unit and the difference V _D of the applied test voltage reaches the ignition voltage V _f of the working gas. A dark discharge occurs between the two electrodes to generate VUV photons. At this time, the photomultiplier tube can test a luminance peak value, which corresponds to point A on the waveform of the scanning electrode test voltage and point C on the waveform of the sustaining electrode test voltage in Figure 9, and test the voltage V _AC between point C and point A The pressure difference between the gas ignition voltage V _f and the voltage V _AC can be calculated, and this pressure difference is mainly V _W formed by the accumulation of escaped electrons in the internal space of the display unit. Moreover, calculating the variation law of t between point A and the starting point B of the measurement cycle can also study the influence of exoelectrons on the discharge stability.

According to the technical solution of the embodiment of the present invention, the corresponding waveform parameters and timing relationship are set by the computer and provided to the control circuit, and the corresponding power device timing signal is generated by the control circuit to form a corresponding test voltage waveform in the driving circuit. This method can achieve relatively flexible and simple waveform control and generation, and can dynamically adjust the shape, quantity and time length of the waveform in the discharge cycle of the applied voltage in the excitation cycle according to the actual display screen test needs. This method of using parameter settings to control the generation of test waveforms is of positive significance for studying the changes in the performance of exoelectron emission under different applied voltage waveforms, that is, under the driving waveform, as well as increasing the number of exoelectron emissions and increasing the test accuracy. .

In an embodiment of the invention, the measurements are primarily made around the voltage difference between the sustain and scan electrodes when a dark discharge point is formed on the scan and sustain electrode ramps, which reflects the exoelectrons formed during the excitation cycle The amount of the number, although the number of escaped electrons is not enough to produce the current required for conventional equipment testing, but the difference V _D of the test voltage applied during discharge can be greatly changed inside the display unit. In addition, through the optical auxiliary system, the study of exoelectron emission can be concentrated on the required specific display unit or specific area, and the obtained results can eliminate environmental noise interference, with high accuracy and signal-to-noise ratio, which is very important for the research display screen The exoelectron emission of dielectric protective film materials is of great significance.

Obviously, those skilled in the art should understand that each module or step of the above-mentioned invention can be realized by a variety of related equipment and devices, and they can be combined in one device or distributed on a network composed of multiple devices, or even solidified into a circuit module to fulfill. Thus, the present invention is not limited to any specific combination of hardware and software.

This embodiment only gives some specific application examples, belongs to the preferred embodiments of the present invention, and is not intended to limit the present invention. For those skilled in the art of related technical research, there are still many modifications and changes in the present invention. Where within the scope of the claimed invention, according to the above-mentioned embodiments, the relevant applied voltage waveforms of different excitation periods, waiting periods and measurement periods are designed, and various modifications, equivalent replacements, improvements, etc. are formed in the prior art. Both the deformation testing device and the testing method should be included in the protection scope of the present invention.

Claims (10)

1. an exoelectron method of testing for media protection membrane material, comprises at least one for the cycle period T tested, it is characterized in that, described cycle period T comprises the voltage carried out continuously successively as follows and applies the cycle,

1) excitation cycle T _s; The maintenance electrode X and scan electrode Y of tested plasma display panel (PDP) are alternately applied to and comprise a discharge cycle T less _cexciting voltage, at a discharge cycle T _cinterior working gas at least completes single step of releasing electric process; Exciting voltage is not less than the firing voltage V in tested plasma display panel (PDP) needed for working gas electric discharge _f;

2) latent period T _w; At excitation cycle T _safter end, the applying voltage on maintenance electrode X and scan electrode Y is placed in and waits on voltage, wait for that voltage is less than the firing voltage V in tested plasma display panel (PDP) needed for working gas electric discharge _f; The life period of the exoelectron that the stand-by period produces when being not more than working gas electric discharge;

3) test period T _r; At latent period T _wafter end, maintenance electrode X and scan electrode Y apply the synchronous test voltage risen respectively, the difference V of the test voltage between scan electrode Y and maintenance electrode X _dincrease gradually and only produce one action process gas discharge;

Detect and record the light signal produced by working gas discharge process in display unit in tested plasma display panel (PDP), the difference V of test voltage when simultaneously obtaining producing light signal between scan electrode Y and maintenance electrode X _d, by formula V _w=V _f-V _dcalculate the fields inside voltage V in display unit _w, according to V _wcalculate the quantity of exoelectron in display unit, complete the once test to media protection membrane material exoelectron.

2. the exoelectron method of testing of a kind of media protection membrane material according to claim 1, is characterized in that, the waveform of described exciting voltage is one or more the combination in square wave, triangular wave, trapezoidal wave, multiple-pulse ripple, sine wave and exponential wave; The waveform of test voltage is one or more combinations in oblique wave, exponential wave, triangular wave, trapezoidal wave.

3. the exoelectron method of testing of a kind of media protection membrane material according to claim 1, it is characterized in that, the described stand-by period is greater than 1ms.

4. the exoelectron method of testing of a kind of media protection membrane material according to claim 1; it is characterized in that; scan electrode Y in described tested plasma display panel (PDP) and maintenance electrode are shorted together respectively and apply voltage in succession, and addressing electrode A is shorted together ground connection setting.

5. the exoelectron method of testing of a kind of media protection membrane material according to claim 1, is characterized in that, by the repeated test of repeatedly same cycle duration T, obtains the difference V of corresponding multiple test voltages respectively _d, average as the difference V of test voltage _dfinal testing result.

6. for realizing an exoelectron test macro for the media protection membrane material of method of testing as claimed in claim 1, it is characterized in that, comprise driving circuit, photomultiplier, oscillograph, computing machine, control circuit and power circuit;

Described driving circuit comprises to be executed alive scan drive circuit for providing and maintains driving circuit; Scan drive circuit and maintain driving circuit and be connected respectively on scan electrode Y in tested plasma display panel (PDP) and maintenance electrode X;

Described photomultiplier is arranged on the image outgoing side of display unit front panel in tested plasma display panel (PDP), for the light signal produced by working gas discharge process in detection display unit, and light signal is converted to electric signal and is input in oscillograph;

Described oscillograph is also carried in applying voltage signal on scan electrode Y and maintenance electrode X for testing correspondence;

Described computing machine is used for setting and executes alive loading parameters, for receiving a road electric signal that oscillograph collects and two tunnels apply voltage signal, and for the calculating of signal data to specific output;

Described control circuit is used for the loading parameters of computer export to be converted to switching signal, and together outputs in driving circuit with the switch control time sequence signal produced;

Described power circuit is used for providing required voltage for driving circuit and control circuit.

7. the exoelectron test macro of a kind of media protection membrane material according to claim 6; it is characterized in that; optics backup system is provided with between described photomultiplier and the front panel of display unit; optics backup system comprises at least one group of eyepiece system, gathers in the target viewing area of target display unit or multiple display unit formation for making the sensing range of photomultiplier.

8. the exoelectron test macro of a kind of media protection membrane material according to claim 7, is characterized in that, in described eyepiece system, superposition arranges optical filter.

9. the exoelectron test macro of a kind of media protection membrane material according to claim 6, is characterized in that, described power circuit adopts pressure adjustable type DC Steady voltage.

10. the exoelectron test macro of a kind of media protection membrane material according to claim 6; it is characterized in that; described scan drive circuit comprises the circuit and square-wave applying voltage waveform control on scan electrode Y, upper slope circuit and lower slope circuit, and described maintenance driving circuit comprises on maintenance electrode X, apply voltage waveform control circuit and square-wave and slope circuit.