CN-121994591-A - Flexible display screen bending angle and conductivity correlation test method and system

CN121994591ACN 121994591 ACN121994591 ACN 121994591ACN-121994591-A

Abstract

The invention provides a method and a system for testing the association of a bending angle and conductivity of a flexible display screen, which relate to the technical field of display screen testing, and comprise the steps of calculating the area of a hysteresis loop of a resistor and the residual increment by synchronously recording the angle and a plurality of electrical parameters in the bending process, distinguishing the damage type by utilizing alternating current impedance, and identifying microcracks through resistance noise power, establishing phase space analysis to identify damage evolution stages and turning points, determining a damage concentrated section, recording a position migration sequence and predicting damage development trend, and realizing accurate assessment and prediction of reliability of the flexible display screen.

Inventors

CHEN WENTAI
TANG LIANG
ZHOU YANG
CHEN WENTA
Chen Haozhuang

Assignees

深圳市康凌源科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260312

Claims (10)

1. The method for testing the association of the bending angle and the conductivity of the flexible display screen is characterized by comprising the following steps: In the process of repeatedly bending the flexible display screen, synchronously recording bending angles and collecting resistance values, alternating current impedance and resistance noise power in a plurality of monitoring sections arranged along the bending axis direction; Calculating a closed loop area formed by the resistance changing along with the angle in each bending cycle as a hysteresis loop area and a resistance residual increment of each monitoring section, wherein alternating current impedance is used for distinguishing interface debonding and body damage, and resistance noise power is used for identifying microcracks; identifying a damage evolution stage and positioning damage turning points through phase space analysis constructed by the resistance residual increment, the hysteresis loop accumulation value and the low-frequency alternating current impedance, and identifying a section with the maximum resistance residual increment growth rate and microcrack as a damage concentration section; Recording a space position migration sequence of the damage concentrated section, and judging a dominant failure mode according to alternating current impedance and resistance noise power change trend; And inputting the spatial position migration sequence and the electrical parameter historical data into a neural network to predict migration direction and migration probability, and dynamically adjusting the acquisition frequency and the position of the detection point by combining the approach degree of the current circulation distance damage turning point.
2. The method of claim 1, wherein the step of simultaneously recording the bend angle and collecting the resistance value, the ac impedance, and the resistive noise power at a plurality of monitoring zones disposed along the bend axis comprises: The method comprises the steps of acquiring a bending angle change curve in real time in the bending process, and dividing the bending angle change curve into a loading stage and an unloading stage, wherein the electrical parameter acquisition of each monitoring section is triggered at a preset angle interval in the loading stage, and the preset angle interval is determined according to an angle interval corresponding to the peak position of the resistance value change rate in the preface bending cycle; Identifying a monitoring section of which the resistance value is not restored to an initial value at the unloading stage as a plastic deformation section, and reducing the preset angle interval for the plastic deformation section in a subsequent bending cycle; And (3) establishing time sequence correlation between the resistance value, alternating current impedance and resistance noise power acquired by each monitoring section in the loading stage and the unloading stage and the corresponding bending angle.
3. The method of claim 1, wherein the step of calculating a closed loop area formed by a resistance as a function of angle for each bending cycle as a hysteresis loop area and a residual increase in resistance for each monitored segment, wherein the alternating current impedance is used to distinguish between interfacial debonding and body damage, and wherein the step of using the resistive noise power to identify microcracks comprises: extracting a data point set forming a closed track from the acquired angle-resistance data points, and calculating the area surrounded by the closed track as a hysteresis loop area through integration; Calculating the difference value between the resistance value and the initial reference value when each bending cycle returns to the initial straight state as a resistance residual increment, and triggering microcrack detection when the resistance residual increment exceeds a preset residual threshold value; In a bending cycle peak value angle maintaining stage for triggering microcrack detection, applying high-frequency pulse current to a corresponding monitoring section as perturbation excitation, collecting high-frequency fluctuation of a resistance signal, calculating power spectrum density, and judging that microcracks exist in the monitoring section when the power spectrum density exceeds a preset power threshold; Collecting transient recovery curves of the resistance value of the monitoring section after the perturbation excitation is removed, identifying a rapid descent stage and a slow descent stage, and respectively calculating rapid decay time and slow decay time; alternating current excitation with different frequencies is applied to a monitoring section entering a critical unsteady state, alternating current impedance is measured, interface debonding is judged when low-frequency impedance amplification exceeds a preset proportion, and body damage is judged when wide-frequency impedance fluctuation exceeds a preset dispersity.
4. The method of claim 3, wherein the step of collecting transient recovery curves for monitoring segment resistance values after the perturbation stimulus is removed, and determining the critical instability condition comprises: Starting high-frequency sampling monitoring section resistance values at the moment of removing perturbation excitation to form a transient recovery curve, performing first derivative calculation on the transient recovery curve to obtain a resistance descending speed curve, and identifying a first peak point in the resistance descending speed curve as a demarcation point of a rapid descending stage and a slow descending stage; defining the time interval from the moment of removing the perturbation excitation to the demarcation point as a rapid decay time, and defining the time interval from the demarcation point to the stable resistance value as a slow decay time; Carrying out exponential function fitting on the fast descending stage to extract a fast decay time constant, carrying out logarithmic function fitting on the slow descending stage to extract a slow decay time constant, and calculating the ratio of the two time constants to be used as a dual-stage decay characteristic parameter; and calculating the second derivative of the double-stage attenuation characteristic parameter to the cycle times, judging that the material stability index increases in speed to generate an inflection point when the second derivative is converted from a negative value to a positive value, and marking the monitoring section to enter a critical unstability state.
5. The method of claim 1, wherein the step of identifying a segment of maximum rate of increase of the resistive residual delta and having microcracks as a concentrated segment of damage by identifying a lesion evolution stage and locating a lesion turning point through phase space analysis constructed of the resistive residual delta, the accumulated value of hysteresis loop, and the low frequency ac impedance comprises: The method comprises the steps of extracting a resistance residual increment, a hysteresis loop accumulation value and low-frequency alternating current impedance of each bending cycle to construct three-dimensional phase space coordinate points, calculating Euclidean distances between adjacent cyclic coordinate points to serve as state evolution step sizes, and marking the state evolution step sizes to enter an accelerated evolution stage when the state evolution step sizes are continuously increased; For the circulation after entering the accelerated evolution stage, calculating the variation coefficient of the resistance residual increment and the hysteresis loop accumulation value in a sliding time window, and judging the accelerated instability state when the inter-circulation variation rate of the variation coefficient is changed from being smaller than a preset stable threshold value to continuously increasing; Calculating mutual information of a resistance residual increment and a hysteresis loop accumulation value for a circulation interval judged to be in an acceleration instability state, and marking that the circulation interval is subjected to damage mechanism transition when the descending amplitude of the mutual information exceeds a preset descending threshold value; Calculating information entropy of three-dimensional phase space coordinate point distribution in a circulation interval in which damage mechanism transformation occurs, and identifying the circulation times of which the information entropy jump amplitude exceeds a preset entropy change threshold value as damage turning points; And in the cycles corresponding to the damage turning points and subsequent cycles, identifying the section with the maximum first derivative and the positive second derivative of the residual increment of the resistance from the monitoring sections with the microcrack marks as the damage concentration section.
6. The method of claim 1, wherein the step of recording the sequence of spatial position transitions of the lesion field and determining dominant failure modes based on alternating current impedance and resistive noise power trend comprises: tracking the spatial position change of the damage concentration section in a continuous bending cycle, recording migration events when the damage concentration section is migrated from the first monitoring section to the second monitoring section, and forming a spatial position migration sequence by arranging the continuous migration events in time sequence; Counting the occurrence frequency of interface debonding judgment results and body damage judgment results corresponding to all monitoring sections in the spatial position migration sequence, and determining a failure mode corresponding to the judgment result with higher occurrence frequency as a dominant failure mode; And cross-verifying the dominant failure mode and the resistance noise power change trend of the corresponding monitoring section, and confirming the judging result when the dominant failure mode is interface debonding and the resistance noise power has no obvious pulse mutation, and confirming the judging result when the dominant failure mode is body damage and the resistance noise power has continuous pulse mutation.
7. The method of claim 6, wherein inputting the spatial location migration sequence and the electrical parameter history data into a neural network predicts a migration direction and a migration probability, and dynamically adjusts the acquisition frequency and the probe location in combination with the proximity of the current circulation distance to the damage turning point comprises: Extracting an alternating current impedance frequency response curve and a resistance noise power time domain fluctuation characteristic corresponding to a migration direction label and a migration moment in the space position migration sequence as input characteristics, outputting migration probability distribution of which each monitoring section becomes a next damage concentrated section through a neural network, and identifying a monitoring section with highest probability from the migration probability distribution as a predicted migration direction; Calculating a difference value of a hysteresis loop accumulation value corresponding to the current cycle and a hysteresis loop accumulation value corresponding to the damage turning point, and increasing the acquisition frequency to a preset multiple of the initial acquisition frequency when the difference value is smaller than a preset difference threshold value and the increase rate sequence shows an ascending trend; And marking the monitoring section corresponding to the predicted migration direction and the adjacent monitoring section along the bending axis direction as a high-risk section, and increasing the resistance value, alternating current impedance and resistance noise power acquisition density of the high-risk section to the preset multiple of other monitoring sections in the subsequent bending cycle.
8. A flexible display screen bending angle and conductivity correlation test system for implementing the method of any one of the preceding claims 1-7, comprising: The data acquisition module is used for synchronously recording the bending angle and acquiring resistance values, alternating current impedance and resistance noise power in a plurality of monitoring sections arranged along the bending axis direction in the process of repeatedly bending the flexible display screen; The characteristic extraction module is used for calculating a closed loop area formed by the resistance changing along with the angle in each bending cycle as a hysteresis loop area and resistance residual increment of each monitoring section, wherein alternating current impedance is used for distinguishing interface debonding and body damage, and resistance noise power is used for identifying microcracks; The damage analysis module is used for identifying a damage evolution stage and positioning damage turning points through phase space analysis constructed by the resistance residual increment, the hysteresis loop accumulation value and the low-frequency alternating current impedance, and identifying a section with the largest resistance residual increment rate and microcrack as a damage concentrated section; The failure mode judging module is used for recording the space position migration sequence of the damage concentrated section and judging a dominant failure mode according to alternating current impedance and resistance noise power change trend; And the self-adaptive regulation and control module is used for inputting the spatial position migration sequence and the electrical parameter historical data into a neural network to predict the migration direction and migration probability, and dynamically regulating the acquisition frequency and the detection point position by combining the approach degree of the current circulation distance damage turning point.
9. An electronic device, comprising: A processor; A memory for storing processor-executable instructions; Wherein the processor is configured to invoke the instructions stored in the memory to perform the method of any of claims 1 to 7.
10. A computer readable storage medium having stored thereon computer program instructions, which when executed by a processor, implement the method of any of claims 1 to 7.

Description

Flexible display screen bending angle and conductivity correlation test method and system Technical Field The invention relates to a display screen testing technology, in particular to a flexible display screen bending angle and conductivity correlation testing method and system. Background The flexible display technology is an important development direction of a new generation of display technology, has the advantages of light weight, thinness, flexibility, impact resistance and the like, and has great application potential in the fields of intelligent wearing, folding mobile phones, curled televisions and the like. Flexible displays are subject to repeated flexing during actual use, which presents serious challenges to the structural integrity and electrical performance of the display. Flexible displays are typically composed of multiple layers of composite materials, including a substrate layer, a conductive layer, a light-emitting layer, a packaging layer, and the like, and repeated bending can cause interface debonding, material fatigue, and microcrack generation, ultimately affecting the conductive performance and display quality of the display. Therefore, the establishment of the correlation test method between the bending angle and the conductivity of the flexible display screen has important significance for evaluating the reliability of the flexible display screen and predicting the service life of the flexible display screen. The existing test method generally adopts static bending at a fixed angle or simple periodic bending test, and cannot monitor the electrical parameter change of the display screen in the bending process in real time, particularly, the dynamic relationship between the bending angle change and the electrical property degradation is difficult to capture, so that the test result is difficult to reflect the property change under the actual use condition. The prior art lacks an effective damage mechanism recognition means, can not accurately distinguish different failure modes such as interface debonding, body material damage, microcracks and the like, and also can not be used for positioning specific damage positions and predicting damage evolution trend, so that the guiding significance of test results is limited, and targeted suggestions are difficult to provide for material improvement and structure optimization. Disclosure of Invention The embodiment of the invention provides a method and a system for testing the correlation of a bending angle and conductivity of a flexible display screen, which can solve the problems in the prior art. In a first aspect of the embodiment of the present invention, a method for testing association between a bending angle and a conductive performance of a flexible display screen is provided, including: In the process of repeatedly bending the flexible display screen, synchronously recording bending angles and collecting resistance values, alternating current impedance and resistance noise power in a plurality of monitoring sections arranged along the bending axis direction; Calculating a closed loop area formed by the resistance changing along with the angle in each bending cycle as a hysteresis loop area and a resistance residual increment of each monitoring section, wherein alternating current impedance is used for distinguishing interface debonding and body damage, and resistance noise power is used for identifying microcracks; identifying a damage evolution stage and positioning damage turning points through phase space analysis constructed by the resistance residual increment, the hysteresis loop accumulation value and the low-frequency alternating current impedance, and identifying a section with the maximum resistance residual increment growth rate and microcrack as a damage concentration section; Recording a space position migration sequence of the damage concentrated section, and judging a dominant failure mode according to alternating current impedance and resistance noise power change trend; And inputting the spatial position migration sequence and the electrical parameter historical data into a neural network to predict migration direction and migration probability, and dynamically adjusting the acquisition frequency and the position of the detection point by combining the approach degree of the current circulation distance damage turning point. The step of synchronously recording the bending angle and collecting the resistance value, the alternating current impedance and the resistance noise power in a plurality of monitoring sections arranged along the bending axis direction comprises the following steps: The method comprises the steps of acquiring a bending angle change curve in real time in the bending process, and dividing the bending angle change curve into a loading stage and an unloading stage, wherein the electrical parameter acquisition of each monitoring section is triggered at a preset angle interval in the loading stage