CN108172152B - Current detection device and detection method of display panel - Google Patents
Current detection device and detection method of display panel Download PDFInfo
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- CN108172152B CN108172152B CN201711383458.XA CN201711383458A CN108172152B CN 108172152 B CN108172152 B CN 108172152B CN 201711383458 A CN201711383458 A CN 201711383458A CN 108172152 B CN108172152 B CN 108172152B
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/006—Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays
Abstract
The invention discloses a current detection device of a display panel, comprising: the device comprises a multi-gear current acquisition resistor, a resistor compensation module, a differential amplification module, a voltage compensation module and a sampling control module; before leaving the factory, the sampling control module fits a fitting function of compensation voltage through typical potential applied in the current detection device, wherein when in testing, the sampling control module controls the voltage compensation module to perform voltage compensation based on the fitting function according to driving signals applied by different display panels and controls the resistance compensation module to perform resistance compensation; and the sampling control module calculates the current flowing through the display panel to be detected according to the output of the compensated differential amplification module and judges whether the display panel is normal or not. The invention also discloses a current detection method of the display panel.
Description
Technical Field
The invention relates to the field of circuit testing. And more particularly, to a current detecting apparatus and a detecting method of a display panel.
Background
When the display panel is produced, in order to eliminate the defective products from flowing into the subsequent process and avoid unnecessary material waste, the corresponding detection is carried out on the defective products. And a corresponding detection interface is reserved on the display panel, and a corresponding signal voltage is applied to the display panel, so that the display panel can be driven to work, and good products and defective products are judged according to the display condition of the panel.
The current detection device of the display panel is typically in the structure shown in fig. 1, and measures the voltage value in the sampling resistor through the instrumentation operational amplifier to calculate the corresponding current value, but the current detection device is greatly affected by the change of the common-mode signal, the change of the common-mode signal causes the reduction of the detection precision, the measurement result is inaccurate, in addition, the current detection device is not suitable for the measurement of the large voltage signal, the display panel which needs the large voltage driving signal cannot be tested, even the detection device is damaged, and when the bidirectional current is detected, the measurement precision is also low.
Therefore, it is desirable to provide a current detection device for a display panel and a detection method thereof, which can detect a bidirectional current while suppressing a common mode signal error while satisfying various voltage signals.
Disclosure of Invention
The invention aims to provide a current detection device of a display panel and a detection method thereof, which can satisfy various voltage signals, restrain common mode signal errors and detect bidirectional current.
In order to achieve the purpose, the invention adopts the following technical scheme:
a current detection device of a display panel, comprising: the device comprises a multi-gear current acquisition resistor, a resistor compensation module, a differential amplification module, a voltage compensation module and a sampling control module, wherein before delivery, the sampling control module fits a fitting function of compensation voltage through a fitting potential applied in a current detection device, and stores the fitting function in the sampling control module for repeated use in subsequent tests; during testing, according to driving signals applied by different display panels, the sampling control module controls the voltage compensation module to perform voltage compensation based on the fitting function and controls the resistance compensation module to perform resistance compensation; and the sampling control module calculates the current flowing through the display panel to be detected according to the output of the compensated differential amplification module and judges whether the display panel to be detected is normal or not.
Preferably, the differential amplification module is a high common mode differential operational amplifier, and is used for detecting under the condition of a large voltage signal or a small voltage signal.
Preferably, the voltage at two ends of the multi-gear current collection resistor is used as an input signal of the differential amplification module, and the resistor compensation module is connected with the low input impedance of the multi-gear current collection resistor.
Preferably, the multi-gear current collection resistor comprises a plurality of gears of sampling resistors, and the resistor compensation module comprises a plurality of gears of compensation resistors corresponding to the multi-gear current collection resistor, wherein the sampling control module controls the gears of the multi-gear current collection resistor and the resistor compensation module to be set according to the value output by the differential amplification module.
Preferably, the voltage compensation module is connected with an input end of the differential amplification module as a reference input end.
A current detection method of a display panel comprises the following steps: under the condition of not connecting the display panel to be tested, inputting a plurality of fitting potentials to obtain a fitting function of the compensation voltage, and storing the fitting function in the sampling control module; accessing a display panel to be tested, applying a driving signal to the display panel to be tested, and obtaining a compensation voltage through a fitting function according to the voltage of the driving signal; based on the value output by the differential amplification module, adjusting the gear of the sampling resistor and adjusting the gear of the corresponding compensation resistor; and calculating the current in the display panel to be tested according to the measured value output by the differential amplification module, and judging whether the display panel to be tested is normal.
Preferably, inputting a plurality of fitting potentials, deriving a fitting function for the compensation voltage comprises: and fitting in the intervals of the reference potentials respectively to obtain a plurality of fitting functions, wherein the obtained fitting functions are piecewise functions.
Preferably, the adjusting the tap position of the sampling resistor based on the value output by the differential amplification module, and the adjusting the tap position of the corresponding compensation resistor comprises: when the current value measured by the set gear of the sampling resistor is close to the upper limit of the measuring range, the sampling control module lowers the gear of the sampling resistor of the multi-gear current collecting resistor and correspondingly adjusts the value of the compensating resistor in the resistor compensating module, and when the current value measured by the set gear of the sampling resistor is close to zero, the sampling control module raises the gear of the sampling resistor of the multi-gear current collecting resistor and correspondingly adjusts the value of the compensating resistor in the resistor compensating module.
Preferably, the value of the compensation resistor is set to be equal to the resistance value of the sampling resistor according to the set corresponding resistance value in the shift position of the sampling resistor.
The invention has the following beneficial effects:
the technical scheme of the invention provides the current detection device and the detection method of the display panel, which can meet various voltage signals, inhibit common-mode signal errors and detect bidirectional current.
Drawings
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings;
fig. 1 is a block diagram illustrating an exemplary typical display panel inspection apparatus in the related art;
FIG. 2 is a block diagram illustrating an exemplary display panel inspection apparatus according to the present disclosure; and
fig. 3 is a flowchart illustrating a test method of an exemplary display panel inspection apparatus according to the present disclosure.
Detailed Description
In order to more clearly illustrate the invention, the invention is further described below with reference to preferred embodiments and the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.
Fig. 2 is a block diagram illustrating an exemplary display panel detection apparatus 20 according to the present disclosure.
As shown in fig. 2, an exemplary display panel detection apparatus 20 according to the present disclosure includes a multi-tap current collection resistor 201, a resistor compensation module 203, a differential amplification module 205, a sampling control module 207, and a voltage compensation module 209.
As can be seen from the figure, the arrows indicate the flow directions of the control signal and the sampling signal, and the sampling control module 207 controls the multi-tap current collecting resistor 201, the resistor compensation module 203, and the voltage compensation module 209 according to the received value from the differential amplification module 205.
The acquisition control module 207 is a processor capable of performing data processing, and may be various types of processor chips such as a single chip processor, a Digital Signal Processor (DSP), a Complex Programmable Logic Device (CPLD), and the like. It will be appreciated that since the processor is a digital processor, for processor chips without an integrated AD converter, the acquisition control module 207 should also have interface circuitry and AD converter circuitry accordingly. It is only necessary to make simple extensions according to the functions and communication protocols of the processor.
For each display panel inspection device 20, a voltage fitting function of the display panel inspection device 20 is obtained before the display panel inspection device 20 is connected to a display panel to be inspected. So that the voltage compensation is performed in real time according to the variation of the input driving signal during the test. The resulting fit function is stored in the memory of the acquisition control module 207 to be called at test time.
As shown in fig. 2, the voltage drop of the multi-step current collecting resistor 201 is used as the input signal of the display panel detecting device 20. The multi-gear current collecting resistor 201 includes a sampling resistor having a plurality of gears, such as a microampere (μ a) gear sampling resistor, a milliamp (mA) gear sampling resistor, an ampere (a) gear sampling resistor, and the like. The gear and the resistance value can be freely adjusted in real time according to the control signal of the sampling control module 207.
Similar to the multi-gear current collection resistor 201, the resistor compensation module 203 is a compensation resistor connected to an input end of the differential amplification module 205 opposite to the multi-gear current collection resistor, and is configured to compensate for a sampling resistor in the multi-gear current collection resistor 201, and therefore, the resistor compensation module 203 includes compensation resistors of multiple gears. And the gear corresponds to the gear of the sampling resistor in the multi-gear current collecting resistor 201, and the resistance value of the resistance compensation module 203 is equal to the resistance value of the sampling resistor according to the set resistance value of the sampling resistor during testing. Preferably, the compensation resistor should be connected to the low input impedance side of the sampling resistor.
In the present embodiment, as shown, the voltage compensation module 209 performs voltage compensation to the differential amplification module 205 according to the control of the sampling control module 207, and it should be understood that the voltage compensation module 209 is connected to the reference input terminal of the differential amplification module 205. For the differential amplification block 205, detection errors can be reduced by real-time compensation when the common mode signal varies. In addition, the differential amplification module 205 of the present disclosure is a high common mode differential operational amplifier to satisfy the test of high driving signal. It should be understood by those skilled in the art that due to the structural characteristics of the operational amplifier, the forward input terminal and the backward input terminal have the "virtual short and virtual break" feature, so that when the compensation voltage is input at the reference voltage input terminal, the range of the input window can be adjusted, and for the input voltage signal exceeding the AD conversion range, the sampling window is changed through the compensation effect, so that the measurement is more flexible.
FIG. 3 is a flow chart diagram 30 illustrating a method of testing an exemplary display panel inspection device 20 according to the present disclosure.
As shown in fig. 3, first, in step S301, in a case where the display panel to be tested is not connected to the display panel detection apparatus 20 of the present disclosure before detection (generally before shipment, and in a case where the stored data is destroyed in a few cases), a fitting potential is input to the input terminal of the display panel detection apparatus 20, a fitting function of the compensation voltage is obtained from the output of the differential amplification module at the fitting potential, and the obtained fitting function is stored in the sampling control module 207.
Since the display panel detection apparatus 20 of the present disclosure is used to test various types of display panels, in order to simplify the test steps, a fitting function suitable for driving signals of different types of display panels should be fitted. Preferably, fitting voltages of +30V, 0V, and-30V may be input, respectively, and the resulting fitting voltages are stored in the sampling control module 207.
In practical application, in order to make the compensation more accurate, a plurality of fitting voltages can be added in the fitting voltage range, and the fitting function in the form of a piecewise function can be obtained by performing piecewise fitting on different intervals.
In step S303, the display panel to be tested is connected in series with the display panel detection apparatus 20, a driving signal is output to the display panel to be tested through the sampling control module 207, the stored fitting function is read according to the value of the input driving signal, the compensation voltage corresponding to the driving signal is obtained, and the compensation voltage of the voltage compensation module 209 is set.
In step S305, according to the value output by the difference amplifying module 205, the sampling control module 207 adjusts the shift of the sampling resistor in the multi-shift current collecting resistor 201, and adjusts the shift of the compensation resistor in the resistor compensation module 203 following the shift of the sampling resistor.
Specifically, because the resistance in the multi-step current collecting resistor 201 is divided into multiple steps, each step corresponds to a different measuring range, when the equivalent range is selected to be too large, for example, when a mA step is selected, if the output value is close to zero, the output value can be adjusted to the μ a step. Conversely, when the range is selected too small, for example, when the μ a range is selected, the output value may be adjusted to the mA range if the output value approaches the full range. Correspondingly, the resistance compensation module 203 selects the same value following the change of the gears and the numerical values of the multi-gear current collection resistor 201 to suppress the influence of the common-mode signal change on the detection.
In step S307, the sampling control module 207 performs calculation according to the measured value output by the differential amplification module 205, obtains a current value flowing in the display panel through ohm' S law, and determines whether the display panel to be detected is normal according to the detected current value.
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.
Claims (9)
1. A current detection device of a display panel, comprising: a multi-gear current acquisition resistor, a resistance compensation module, a differential amplification module, a voltage compensation module and a sampling control module,
before delivery, the sampling control module fits a fitting function of the compensation voltage through a fitting potential applied in the current detection device, and stores the fitting function in the sampling control module for repeated use in subsequent tests;
when in testing, the sampling control module applies different driving signals according to different display panels or different tests of the display panels, and the sampling control module controls the voltage compensation module to perform voltage compensation based on the fitting function and controls the resistance compensation module to perform resistance compensation;
and the sampling control module calculates the current flowing through the display panel to be detected according to the compensated output of the differential amplification module, and judges whether the display panel to be detected is normal.
2. The current detection device of claim 1, wherein the differential amplifier module is a high common mode differential operational amplifier for detecting a large voltage signal or a small voltage signal.
3. The current detection device of the display panel according to claim 2, wherein a voltage across the multi-tap current collection resistor is used as an input signal of the differential amplification module, and the resistance compensation module is connected to a low input impedance side of the multi-tap current collection resistor.
4. The current detection device of the display panel according to claim 1, wherein the multi-tap current collection resistor includes a sampling resistor of a plurality of taps, and the resistance compensation module includes a compensation resistor of a plurality of taps corresponding to the multi-tap current collection resistor,
the sampling control module controls the setting of the multi-gear current acquisition resistor and the gear of the resistor compensation module according to the value output by the differential amplification module.
5. The current detection device of a display panel according to claim 3 or 4,
and the voltage compensation module is connected with the input end serving as a reference input end in the differential amplification module.
6. A current detection method of a display panel for use in the current detection device according to any one of claims 1 to 5, characterized by comprising the steps of:
under the condition of not connecting the display panel to be tested, inputting a plurality of fitting potentials to obtain a fitting function of the compensation voltage, and storing the fitting function in the sampling control module;
accessing the display panel to be tested, applying a driving signal to the display panel to be tested, and obtaining a compensation voltage through the fitting function according to the voltage value of the driving signal;
based on the value output by the differential amplification module, adjusting the gears of the multi-gear current acquisition resistor and adjusting the gears of the corresponding compensation resistor; and
and calculating the current in the display panel to be tested according to the measured value output by the differential amplification module, and judging whether the display panel to be tested is normal or not.
7. The method for detecting current of a display panel according to claim 6, wherein the inputting a plurality of fitting potentials and deriving a fitting function of the compensation voltage comprises:
and fitting in the intervals of the reference potentials respectively to obtain a plurality of fitting functions, wherein the obtained fitting functions are piecewise functions.
8. The current detection method of the display panel according to claim 6, wherein the adjusting the shift of the multi-shift current collection resistor based on the value output by the differential amplification module comprises:
when the current value measured by the set gear of the sampling resistor is close to the upper limit of the measuring range, the sampling control module lowers the gear of the sampling resistor of the multi-gear current acquisition resistor, correspondingly adjusts the gear of a compensation resistor in the resistor compensation module, and
when the current value measured by the set gear of the sampling resistor is close to zero, the sampling control module adjusts the gear of the sampling resistor of the multi-gear current acquisition resistor to be high, and correspondingly adjusts the gear of the compensation resistor in the resistor compensation module.
9. The current detection method of a display panel according to claim 8, wherein a value of the compensation resistor is set to be equal to a resistance value of the sampling resistor in accordance with a corresponding resistance value in a shift position of the set sampling resistor.
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| CN109975690A (en) * | 2019-03-28 | 2019-07-05 | 华东师范大学 | A kind of integrated circuit multi gear position current detection means |
| CN111913595B (en) * | 2019-05-10 | 2024-03-08 | 北京钛方科技有限责任公司 | Touch pad pressing force detection system and method |
| CN110880293B (en) * | 2019-12-09 | 2021-04-06 | 合肥视涯技术有限公司 | Pixel compensation circuit, display panel and pixel compensation method |
| CN111398888A (en) * | 2020-04-14 | 2020-07-10 | 南方电网科学研究院有限责任公司 | Low-power-consumption dynamic monitoring device and equipment of intelligent electric meter and using method |
| CN113532805A (en) * | 2020-04-15 | 2021-10-22 | 华兴源创(成都)科技有限公司 | Fault detection method and device of display panel detection equipment |
| CN113075446B (en) * | 2021-03-31 | 2023-06-16 | 北京润科通用技术有限公司 | Current acquisition method and device |
| CN114487582B (en) * | 2022-01-30 | 2023-04-14 | 北京思凌科半导体技术有限公司 | Current detection device and current detection system |
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