Test method, test device, test equipment and computer readable storage medium

Abstract

The invention discloses a test method, a test device, test equipment and a computer readable storage medium. The test method is used for the display module. The test method comprises the following steps: increasing the gate turn-off voltage of a driving transistor; under the condition that the display module has a vertical crosstalk phenomenon, recording the gate turn-off voltage of the target area as a voltage threshold value; determining a drain current corresponding to the voltage threshold as a current threshold; carrying out a reliability test on the driving transistor for a set time so as to determine a test drain current according to a preset gate turn-off voltage of the display module; and when the test drain current is smaller than the current threshold, determining that the display module passes the test. According to the testing method, the direct factor drain current generating the vertical crosstalk phenomenon serves as a parameter for evaluating the display module, when the tested drain current is smaller than the current threshold value, the set preset grid closing voltage enables the display module not to generate the vertical crosstalk phenomenon within the set time, and the set preset grid closing voltage is appropriate.

Description

Technical Field

[0001] The present invention relates to the technical field of display devices, and more particularly, to a test method, a test device, a test equipment, and a computer-readable storage medium. Background Art

[0002] Outdoor liquid crystal display (LCD) products often need to face the use environment of high temperature and high brightness. Such a use environment will cause an increase in the leakage current of transistors in the LCD. At the same time, high temperature and high brightness also exacerbate the deterioration of transistors, resulting in a more rapid increase in the leakage current. A large enough leakage current will cause the occurrence of vertical crosstalk. The gate-off voltage of the driving transistor will affect the leakage current. Setting the gate-off voltage range for the LCD product can avoid excessive leakage current of the LCD product from causing vertical crosstalk. However, the gate-off voltage range needs to be set within a suitable range. Therefore, a corresponding test method is required to test whether the gate-off voltage range meets the requirements. Summary of the Invention

[0003] Embodiments of the present invention provide a test method, a test device, a test equipment, and a computer-readable storage medium.

[0004] Embodiments of the present invention provide a test method, which is used for a display module. The display module includes a driving transistor. The test method includes: raising the gate-off voltage of the driving transistor; when a vertical crosstalk phenomenon appears in the display module, recording the gate-off voltage of a target area as a voltage threshold, where the target area is located in the display area of the display module; determining the drain current corresponding to the voltage threshold as a current threshold; performing a reliability test on the driving transistor for a set time to determine a test drain current according to a preset gate-off voltage of the display module; and when the test drain current is less than the current threshold, determining that the display module passes the test.

[0005] In this way, taking the drain current, which is the direct factor causing the vertical crosstalk phenomenon, as a parameter for evaluating the display module, raising the gate-off voltage of the driving transistor, recording the gate-off voltage at which the vertical crosstalk phenomenon appears as the voltage threshold, and determining the drain current corresponding to the voltage threshold to obtain the current threshold as the evaluation parameter, and performing a reliability test on the display module for a set time, determining the test drain current according to the preset gate-off voltage of the set display module. When the test drain current is less than the current threshold, the set preset gate-off voltage is appropriate, so that the display module will not have a vertical crosstalk phenomenon within the set time, realizing the test of the preset gate-off voltage.

[0006] In some embodiments, determining the drain current corresponding to the voltage threshold includes: determining the correspondence between the gate-off current and the drain current of the display module; and determining the current threshold according to the correspondence and the voltage threshold.

[0007] In this way, by determining the correspondence between the gate-off current and the drain current of the display module, the corresponding drain current can be determined according to the voltage threshold to be used as the current threshold, thus realizing the determination of the current threshold.

[0008] In some embodiments, the display module includes a backlight layer. Before raising the gate-off voltage of the driving transistor, the test method further includes: adjusting the brightness of the backlight layer to a set backlight brightness; before determining the correspondence between the gate-off current and the drain current of the display module, determining the drain current corresponding to the voltage threshold further includes: applying a top light with a set top light brightness to the driving transistor, where the top light is used to irradiate the channel of the driving transistor, and the set top light brightness is the product of the set backlight brightness and a set coefficient.

[0009] In this way, by applying a top light that matches the backlight brightness, the accuracy of the obtained current threshold can be improved, thereby improving the accuracy of the test.

[0010] In some embodiments, after performing a reliability test on the driving transistor for a set time, the test method further includes: determining the variation relationship between the drain-off current and time according to the reliability result of the reliability test; and determining the lifespan of the display module according to the time corresponding to the current threshold in the variation relationship.

[0011] In this way, the variation relationship between the drain-off current and time can be determined according to the reliability result obtained from the reliability test, and then the lifespan of the display module can be determined according to the time corresponding to the current threshold in the variation relationship. Moreover, the current threshold is determined according to a preset gate-off voltage, that is, the lifespan of the display module is evaluated according to the preset gate-off voltage.

[0012] In some embodiments, performing a reliability test on the driving transistor for a set time includes: adjusting the gate voltage of the driving transistor, the frame duration of the display module, and the scanning range to complete the reliability test on the driving transistor for the set time within a set test time, where the set test time is shorter than the set time.

[0013] In this way, by setting the gate voltage of the driving transistor, the frame duration of the display module, and the scanning range, the long-time reliability test on the driving transistor can be completed in a shorter time, saving the reliability test time and energy consumption.

[0014] In some embodiments, before the gate-off voltage of the recording target area reaches the voltage threshold, the test method further includes: when the brightness ratio is greater than a set ratio, determining that the display module has a vertical crosstalk phenomenon, where the brightness ratio is the ratio of the difference between the brightness value of the target area and the set brightness value to the set brightness value.

[0015] In this way, using the brightness ratio as the criterion for determining whether the display module has a vertical crosstalk phenomenon, when the brightness ratio is greater than the set ratio, it is determined that the display module has a vertical crosstalk phenomenon; when the brightness ratio is less than or equal to the set ratio, it is determined that the display module does not have a vertical crosstalk phenomenon, avoiding the inaccuracy caused by the subjectivity of using the human eye to judge the vertical crosstalk phenomenon and improving the accuracy of evaluating the voltage threshold.

[0016] In some embodiments, the test method further includes: determining a reference drain current according to the brightness difference, the set ratio, and the frame duration per frame. The brightness difference is the brightness difference of the target area at a first moment and a second moment. When displaying a preset picture, the source-drain voltage difference of the driving transistor in the target area is the largest within the first moment to the second moment, and the source-drain voltage difference is used to represent the voltage difference between the drain and the source of the driving transistor; determining a current threshold according to the reference drain current and the drain current corresponding to the voltage threshold.

[0017] In this way, the theoretical reference drain current can be determined according to the brightness difference, the set ratio, and the frame duration per frame, and then the current threshold can be determined according to the reference drain current and the drain current corresponding to the voltage threshold, so as to provide a criterion for judging the current threshold.

[0018] An embodiment of the present invention provides a test device for a display module. The display module includes a driving transistor. The test device includes an adjustment module, a recording module, a first determination module, a test module, and a second determination module. The adjustment module is used to increase the gate-off voltage of the driving transistor; the recording module is used to record that the gate-off voltage of the target area is the voltage threshold when the display module has a vertical crosstalk phenomenon, and the target area is located in the display area of the display module; the first determination module is used to determine the drain current corresponding to the voltage threshold as the current threshold; the test module is used to perform a reliability test on the driving transistor for a set time to determine the test drain current of the test target according to the preset gate-off voltage of the display module; the second determination module is used to determine that the display module passes the test when the test drain current is less than the current threshold.

[0019] Thus, taking the drain current, which is the direct factor causing the vertical crosstalk phenomenon, as a parameter for evaluating the display module, the gate-off voltage of the driving transistor is increased, the gate-off voltage at which the vertical crosstalk phenomenon appears is recorded as the voltage threshold, and the drain current corresponding to the voltage threshold is determined to obtain the current threshold as the evaluation parameter. Then, a reliability test for the display module is performed for a set time. The test drain current is determined according to the preset gate-off voltage of the set display module. When the test drain current is less than the current threshold, the set preset gate-off voltage is appropriate, so that the display module will not have the vertical crosstalk phenomenon within the set time, realizing the test of the preset gate-off voltage.

[0020] An embodiment of the present invention provides a test device, which includes one or more processors and a memory. The memory stores a computer program. When the computer program is executed by the processor, the steps of the test method in any of the above embodiments are implemented.

[0021] Thus, taking the drain current, which is the direct factor causing the vertical crosstalk phenomenon, as a parameter for evaluating the display module, the gate-off voltage of the driving transistor is increased, the gate-off voltage at which the vertical crosstalk phenomenon appears is recorded as the voltage threshold, and the drain current corresponding to the voltage threshold is determined to obtain the current threshold as the evaluation parameter. Then, a reliability test for the display module is performed for a set time. The test drain current is determined according to the preset gate-off voltage of the set display module. When the test drain current is less than the current threshold, the set preset gate-off voltage is appropriate, so that the display module will not have the vertical crosstalk phenomenon within the set time, realizing the test of the preset gate-off voltage.

[0022] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the steps of the test method in any of the above embodiments are implemented.

[0023] Thus, taking the drain current, which is the direct factor causing the vertical crosstalk phenomenon, as a parameter for evaluating the display module, the gate-off voltage of the driving transistor is increased, the gate-off voltage at which the vertical crosstalk phenomenon appears is recorded as the voltage threshold, and the drain current corresponding to the voltage threshold is determined to obtain the current threshold as the evaluation parameter. Then, a reliability test for the display module is performed for a set time. The test drain current is determined according to the preset gate-off voltage of the set display module. When the test drain current is less than the current threshold, the set preset gate-off voltage is appropriate, so that the display module will not have the vertical crosstalk phenomenon within the set time, realizing the test of the preset gate-off voltage.

[0024] The additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, where:

[0026] Figure 1 is a schematic flowchart of the test method according to an embodiment of the present invention;

[0027] Figure 2 is a schematic diagram of the test device according to an embodiment of the present invention;

[0028] Figure 3 is a schematic diagram of the preset screen according to an embodiment of the present invention;

[0029] Figure 4 is a schematic diagram of the data signal voltage and pixel voltage at point A and point A' according to an embodiment of the present invention;

[0030] Figure 5 is a schematic flowchart of the test method according to an embodiment of the present invention;

[0031] Figure 6 is a schematic diagram of the first determination module according to an embodiment of the present invention;

[0032] Figure 7 is a schematic flowchart of the test method according to an embodiment of the present invention;

[0033] Figure 8 is a schematic diagram of the test device according to an embodiment of the present invention;

[0034] Figure 9 is a schematic diagram of the curve of drain current and gate voltage of an embodiment according to an embodiment of the present invention;

[0035] Figure 10 is a schematic flowchart of the test method according to an embodiment of the present invention;

[0036] Figure 11 is a schematic diagram of the test device according to an embodiment of the present invention;

[0037] Figure 12 is a schematic diagram of the curve of gate turn-off voltage and time according to an embodiment of the present invention;

[0038] Figure 13 is a schematic flowchart of the test method according to an embodiment of the present invention;

[0039] Figure 14 is a schematic diagram of the test device according to an embodiment of the present invention;

[0040] Figure 15 is a schematic flowchart of the test method according to an embodiment of the present invention;

[0041] Figure 16 It is a schematic diagram of the test device according to an embodiment of the present invention;

[0042] Figure 17 It is a schematic flowchart of the test method according to an embodiment of the present invention;

[0043] Figure 18 It is a schematic diagram of the test device according to an embodiment of the present invention. Specific Embodiments

[0044] The following details the embodiments of the present invention. The embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention and should not be construed as a limitation of the present invention.

[0045] Outdoor liquid crystal display (LCD) products often need to face high-temperature and high-brightness usage environments. Such usage environments can cause an increase in the leakage current of transistors in the LCD. At the same time, high temperature and high brightness also exacerbate the deterioration of the transistors, resulting in a more rapid increase in the leakage current. A sufficiently large leakage current can cause vertical crosstalk to occur. The gate-off voltage of the driving transistor affects the leakage current. Setting a range of gate-off voltages for the LCD product can prevent the leakage current of the LCD product from being too large and causing vertical crosstalk. However, the range of gate-off voltages needs to be set within a suitable range. Therefore, a corresponding test method is required to test whether the range of gate-off voltages meets the requirements.

[0046] Please refer to Figure 1 , an embodiment of the present invention provides a test method for a display module. The display module includes a driving transistor. The test method includes:

[0047] 01: Increase the gate-off voltage of the driving transistor;

[0048] 02: When a vertical crosstalk phenomenon occurs in the display module, record the gate-off voltage of the target area as the voltage threshold. The target area is located within the display area of the display module;

[0049] 03: Determine the drain current corresponding to the voltage threshold as the current threshold;

[0050] 04: Perform a reliability test on the driving transistor for a set time to determine the test drain current according to the preset gate-off voltage of the display module;

[0051] 05: When the test drain current is less than the current threshold, determine that the display module passes the test.

[0052] Specifically, please refer to Figure 2, the test method according to the embodiments of the present invention can be implemented by the test device 100 according to the embodiments of the present invention. The test device 100 includes an adjustment module 10, a recording module 20, a first determination module 30, a test module 40, and a second determination module 50. That is to say, the adjustment module 10 can be used to increase the gate-off voltage of the driving transistor; the recording module 20 can be used to record the gate-off voltage of the target area as the voltage threshold when the vertical crosstalk phenomenon appears in the display module, and the target area is located within the display area of the display module; the first determination module 30 can be used to determine the drain current corresponding to the voltage threshold as the current threshold; the test module 40 can be used to perform a reliability test on the driving transistor for a set time to determine the test drain current of the test target according to the preset gate-off voltage of the display module; the second determination module 50 can be used to determine that the display module passes the test when the test drain current is less than the current threshold.

[0053] Among them, the display module includes pixels, data signal lines, and gate driving lines. The gate driving lines are used to control the driving transistor to turn on. When the driving transistor is turned on, the driving transistor is used to drive the pixels to display. The data signal lines are used to provide data signal voltages to the pixels to control the display brightness of the pixels. The drain of the driving transistor is connected to the pixel, the source of the driving transistor is connected to the data signal line, and the gate of the driving transistor is connected to the gate driving line.

[0054] In the related art, please refer to Figure 3 , taking a preset picture as an example for illustration. The preset picture includes a first part and a second part. The first part displays an L80 grayscale picture, and the second part displays an L255 white picture. The second part occupies 1 / 2 of the vertical length. The part from the upper edge of the second part to the upper edge of the preset picture occupies 1 / 4 of the vertical length, and the part from the lower edge of the second part to the lower edge of the preset picture occupies 1 / 4 of the vertical length. The pixel voltage Vpixel is the pixel driving voltage provided by the gate driving line, and the data signal voltage Vdata is the voltage provided by the data signal line. Taking the charging of the positive frame voltage at points A and A' of the pixels as the starting point T1, where point A is located at the junction of the first part and the second part, and point A' is located within the first part. The corresponding data signal voltage Vdata and pixel voltage Vpixel change as Figure 4 , Vpixel, Vdata, and Vpixel - Vdata correspond to the TFT gate Vg, source voltage Vs, and drain voltage Vds respectively. Therefore, the TFT source-drain voltage difference Vds = Vpixel - Vdata. The relationship between the drain voltage and the gate voltage at points A and A' during the time periods from T3 to T4 and from T6 to T7 is shown in Table 1. From Figure 4 and Table 1, it can be seen that there are significant differences in Vds at points A and A' during the periods from T3 to T4 and from T6 to T7. The source-drain voltage difference Vds of point A during the period from T3 to T4 is V +L80 -V-L255 ; The source-drain voltage difference Vds of point A in the T6 to T7 section is V -L80 -V +L255 ; The source-drain voltage difference Vds of point A' in the T3 to T4 section is V +L80 -V -L80 ; The source-drain voltage difference Vds of point A' in the T6 to T7 section is V -L80 -V +L80 . According to the drain voltage difference between point A and point A', the drain current difference between point A and point A' can be determined. The drain current difference between point A and point A' is mainly reflected in the positive frame during the time period from T3 to T4, and the drain current difference increases with the increase of the gate-off voltage Vgl. When the drain current difference increases to a certain value, the voltage difference between point A and point A' will change qualitatively from quantitative change, so that the human eye can feel an obvious brightness difference, that is, the vertical crosstalk (V-crosstalk, V-ct) phenomenon occurs; since the drain current of point A in the positive frame during the time period from T3 to T4 is much larger than that in other time periods, it can be approximately considered that the drain current value of point A in this time period is the difference between the drain currents of point A and point A'.

[0055] Position Time period Vg (V) -8 -7 -6 -5 -4 -3 -2 A T3 to T4 <![CDATA[V +L80 -V -L255 > 4.925 8.976 17.492 36.074 81.651 209.564 615.218 A T6 to T7 <![CDATA[V +L80 -V -L80 > 1.161 1.498 1.935 2.923 4.844 8.382 15.878 A’ T3 to T4 <![CDATA[V -L80 -V +L255 > 2.497 2.215 2.771 3.688 5.952 9.952 18.228 A’ T6 to T7 <![CDATA[V -L80 -V +L80 > 0.606 0.632 1.222 2.231 3.93 7.268 14.089

[0056] Table 1

[0057] Therefore, in the embodiment of the present invention, the gate-off voltage Vgl of the driving transistor is increased until the vertical crosstalk phenomenon appears in the target area. When the vertical crosstalk appears in the target area, record the gate-off voltage at this time as the voltage threshold Vgl_NG, and use the drain-off current Ioff corresponding to the voltage threshold Vgl_NG as the current threshold Ioff_spec. Since the direct influencing factor for the occurrence of vertical crosstalk is the drain-off current Ioff of the transistor, Ioff_spec can be used as the standard for judging whether the display module has vertical crosstalk. If the drain-off current Ioff exceeds Ioff_spec, the display module will have the vertical crosstalk phenomenon; if the drain-off current Ioff does not exceed Ioff_spec, the display module will not have the vertical crosstalk phenomenon.

[0058] In addition, a reliability test is performed on a partial array substrate composed of driving transistors for a set time, which can be 1000 hours, that is, a reliability test is performed on the driving transistors for 1000 hours to obtain the results after 1000 hours of deterioration of the driving transistors, and the Id-Vg-1000 curve is tested. Each display module has a set gate-off voltage range Vgl margin, and the preset gate-off voltage is the maximum value of the set gate-off voltage range. According to the drain-off current Ioff corresponding to the preset gate-off voltage in the Id-Vg curve, the drain-off current Ioff and the current threshold Ioff_spec are compared. When the drain-off current is greater than the current threshold Ioff_spec, the display module with the preset gate-off voltage will not have a vertical crosstalk phenomenon, and then the display module passes the test. When performing the test, there is no need to use the entire display device for testing, and only the display module can be used for testing. The display module includes an array substrate. The test method can be used to test the array substrate, that is, a suitable preset gate-off voltage can be tested at the Array (array substrate) stage, and whether the preset gate-off voltage is appropriate can be predicted in the early stage of the product, avoiding related defects caused by inappropriate setting of the preset gate voltage, reducing costs, and saving power consumption.

[0059] In this way, taking the drain current, which is the direct factor causing the vertical crosstalk phenomenon, as a parameter for evaluating the display module, the gate-off voltage of the driving transistor is increased, and the gate-off voltage at which the vertical crosstalk phenomenon occurs is recorded as the voltage threshold, and the drain current corresponding to the voltage threshold is determined to obtain the current threshold as the evaluation parameter. A reliability test is performed on the display module for a set time, and the test drain current is determined according to the preset gate-off voltage of the set display module. When the test drain current is less than the current threshold, the set preset gate-off voltage is appropriate, so that the display module will not have a vertical crosstalk phenomenon within the set time, realizing the test of the preset gate-off voltage.

[0060] Please refer to Figure 5 , in some embodiments, step 03 (determining the drain current corresponding to the voltage threshold) includes:

[0061] 0301: Determine the correspondence between the gate-off current and the drain current of the display module;

[0062] 0302: Determine the current threshold according to the correspondence and the voltage threshold.

[0063] Specifically, please refer to Figure 6, step 0301 can be implemented by the first determination sub-module 31 of the first determination module 30, and step 0302 can be implemented by the second determination sub-module 32 of the first determination module 30. That is to say, the first determination sub-module 31 can be used to determine the correspondence between the gate-off current and the drain current of the display module; the second determination sub-module 32 can be used to determine the current threshold according to the correspondence and the voltage threshold. Test the correspondence between the drain current and the gate voltage of the display module. The test method can be to change the gate voltage Vg while determining the drain voltage and the source voltage, and record the corresponding drain current Id, so as to obtain the Id-Vg curve, and determine the drain current corresponding to the voltage threshold Vgl_NG in the Id-Vg curve as the current threshold Ioff_spec.

[0064] In this way, by determining the correspondence between the gate-off current and the drain current of the display module, the corresponding drain current can be determined according to the voltage threshold to be used as the current threshold, thus realizing the determination of the current threshold.

[0065] Please refer to Figure 7 , in some embodiments, the display module includes a backlight layer. Before step 01 (raising the gate-off voltage of the driving transistor), the test method further includes:

[0066] 06: Adjust the brightness of the backlight layer to the set backlight brightness.

[0067] Before step 0301 (determining the correspondence between the gate-off current and the drain current of the display module), determining the drain current corresponding to the voltage threshold further includes:

[0068] 0303: Apply a top light with a set top light brightness to the driving transistor. The top light is used to irradiate the channel of the driving transistor, and the set top light brightness is the product of the set backlight brightness and the set coefficient.

[0069] Specifically, please refer to Figure 8 , step 06 can be implemented by the adjustment module 60 of the test device 100 according to the embodiments of the present invention, and step 0303 can be implemented by the top light sub-module 33 of the first determination module 30. That is to say, the adjustment module 60 can be used to adjust the brightness of the backlight layer to the set backlight brightness; the top light sub-module 33 can be used to apply a top light with a set top light brightness to the driving transistor. The top light is used to irradiate the channel of the driving transistor, and the set top light brightness is the product of the set backlight brightness and the set coefficient.

[0070] Among them, the driving transistor can be a thin film transistor (TFT). When testing the display module, the light intensity L of the backlight applied inside the display module enters the channel of the TFT after reflection or refraction T and the test backlight intensity L BThe ratio is a, and the light intensity L entering the TFT channel of the entire LCD display device M and the backlight intensity L of the entire machine B ’s ratio is b. a may be much larger than b, which may lead to a lower accuracy of the test results. If an appropriate Ioff Spec is to be measured, the light intensity entering the TFT channel during testing and when the entire machine is working needs to be the same, that is, it is necessary to make L T = L M , L B *a = L B ’*b. Therefore, in the embodiment of the present invention, top light L is directly added to the channel of the TFT top . The set backlight brightness can be the pre-set backlight brightness L B1 , and the set top light brightness can be the pre-set top light brightness L top1 = L B1 ×c, where c is a constant, to satisfy L T = L M .

[0071] In one embodiment, the set coefficient c = 0.55‰. The backlight brightness of the display module is adjusted to L1, L2, and L3 respectively, and the corresponding voltage thresholds V1, V2, and V3 are measured respectively. According to the set coefficient, top lights L T1 , L T2 , L T3 , L T1 corresponding to the backlight brightness L1, L T2 corresponding to the backlight brightness L2, and L T3 corresponding to the backlight brightness L3 are added to the display module respectively; please refer to Figure 9 , and the Id-Vg curves (Ioff1-Vg1, Ioff1-Vg2, and Ioff1-Vg3) are measured respectively, and the drain currents Ioff1, Ioff2, and Ioff3 corresponding to the voltage thresholds V1, V2, and V3 are determined respectively according to the measured Id-Vg curves as the current thresholds. Theoretically, Ioff1 = Ioff2 = Ioff3 = Ioff_spec.

[0072] In this way, by adding a top light that matches the backlight brightness, the accuracy of the obtained current threshold can be improved, thereby improving the accuracy of the test.

[0073] Please refer to Figure 10 , in some embodiments, after step 04 (performing a reliability test on the driving transistor for a set time), the test method further includes:

[0074] 07: According to the reliability result of the reliability test, determine the change relationship between the drain-off current and time;

[0075] 08: Determine the lifespan of the display module according to the time corresponding to the current threshold in the variation relationship.

[0076] Specifically, please refer to Figure 11 , step 07 can be implemented by the third determination module 70 of the test device 100 according to an embodiment of the present invention, and step 08 can be implemented by the fourth determination module 80 of the test device 100 according to an embodiment of the present invention. That is to say, the third determination module 70 can be used to determine the variation relationship between the drain-off current and time according to the reliability result of the reliability test; the fourth determination module 80 can be used to determine the lifespan of the display module according to the time corresponding to the current threshold in the variation relationship.

[0077] Among them, the drain-off current Ioff gradually increases during the reliability test and gradually tends to the limit value after increasing to a certain extent. Please refer to Figure 12 , the variation curve of the drain-off current Ioff with time can be determined through the reliability result of the outdoor environment reliability test. As the deterioration time increases, the drain-off current Ioff gradually rises. According to the time corresponding to the current threshold Ioff_spec in the variation curve, the time when the display module has vertical crosstalk can be determined, and thus the lifespan (T_spec) of the display module can be determined.

[0078] In this way, the variation relationship between the drain-off current and time can be determined according to the reliability result obtained from the reliability test, and then the lifespan of the display module can be determined according to the time corresponding to the current threshold in the variation relationship. Moreover, the current threshold is determined according to the preset gate-off voltage, that is, the evaluation of the lifespan of the display module according to the preset gate-off voltage is realized.

[0079] Please refer to Figure 13 , in some embodiments, step 04 (conduct a reliability test on the driving transistor for a set time) includes:

[0080] 0401: Adjust the gate voltage of the driving transistor, the per-frame duration of the display module, and the scanning range to complete the reliability test on the driving transistor for a set time within the set test time, and the set test time is shorter than the set time.

[0081] Specifically, please refer to Figure 14 , step 0401 can be implemented by the adjustment sub-module 41 of the test module 40. That is to say, the adjustment sub-module 41 can be used to adjust the gate voltage of the driving transistor, the per-frame duration of the display module, and the scanning range to complete the reliability test on the driving transistor for a set time within the set test time, and the set test time is shorter than the set time.

[0082] Among them, the embodiment of the present invention combines a reliability test model to adjust the gate voltage of the driving transistor, the duration of each frame of the display module, and the scanning range. By means of the method of combining a high-temperature and high-brightness environment with the TFT gate bias voltage, the deterioration degree of the TFT reaches the result of the reliability test for the set time within the set test time. The set test time can be 1 hour or 2 hours, and the set time can be 1000 hours, that is, the set test time is much less than the set time. The suitability of the preset gate-off voltage Vgl is quickly tested and evaluated in a short time to evaluate whether the gate-off voltage range Vgl_margin of the display module is reasonably set.

[0083] In this way, by setting the gate voltage of the driving transistor, the duration of each frame of the display module, and the scanning range, the long-term reliability test of the driving transistor can be completed in a relatively short time, saving the reliability test time and energy consumption.

[0084] Please refer to Figure 15 , in some embodiments, before step 02 (recording the gate-off voltage of the target area as the voltage threshold), the test method further includes:

[0085] 09: When the brightness ratio is greater than the set ratio, it is determined that the display module has a vertical crosstalk phenomenon. The brightness ratio is the ratio of the difference between the brightness value of the target area and the set brightness value to the set brightness value.

[0086] Specifically, please refer to Figure 16 , step 09 can be implemented by the fifth determination module 90 of the test device 100 according to the embodiment of the present invention. That is to say, the fifth determination module 90 can be used to determine that the display module has a vertical crosstalk phenomenon when the brightness ratio is greater than the set ratio. The brightness ratio is the ratio of the difference between the brightness value of the target area and the set brightness value to the set brightness value.

[0087] Among them, in the related art, the evaluation of the vertical crosstalk of the display module is mostly subjectively judged by the human eye. However, the judgment result of the human eye is often subjective and inaccurate. Therefore, the embodiment of the present invention uses the brightness ratio as the judgment criterion. The brightness ratio can be the ratio of the absolute value of the difference between the brightness value of the target area and the set brightness value to the set brightness value. The target area can be the pixel at point A, and the set brightness value can be the brightness value L of point A when displaying the L80 gray-scale picture L80 , when displaying the preset picture, the brightness value of point A is L V , that is, the brightness ratio is |L V -L L80 | / L L80 =|ΔL| / L L80 , the set ratio can be 1.5%, 2%, 3%, etc. In this embodiment, the set ratio is taken as 2% for illustration, that is, when |L V -LL80 | / L L80 = |ΔL| / L L80 When it is greater than 2%, it is determined that the display module has a vertical crosstalk phenomenon, and it is recorded as NG, so as to achieve an accurate evaluation of the vertical crosstalk phenomenon. Since the leakage difference is mainly caused by the period from the positive frame T3 to T4, it can be considered that the average brightness difference within 2 frame times (2T) is 2%, and it is mainly contributed by the brightness difference in the time period from T3 to T5 (0.5T + t1, where t1 is proportional to the vertical distance between point A and the second part, and t1 ≤ 0.25T), that is, it is approximately considered that within the time periods from T1 to T3 and from T5 to T8, the brightness of point A is the same under the preset picture and the L80 gray scale picture, and the average brightness is L under both pictures, where L is the brightness of point A at the moment of T3.

[0088] In one embodiment, please refer to Table 2. Top light is added to the driving transistor channel with different setting coefficients, and the current threshold Ioff_spec of two target areas (position 1 and position 2) of the display module is tested; among them, the Ioff1 fluctuation and the Ioff2 fluctuation are respectively the ratios of the maximum value to the minimum value of the current thresholds measured within position 1 and position 2 at this setting coefficient, and the Ioff area fluctuation is expressed as the ratio of the maximum value to the minimum value of the current thresholds measured at this setting coefficient. It can be seen from the table that the setting coefficient c = 0.55‰ is more appropriate.

[0089]

[0090] Table 2

[0091] In this way, using the brightness ratio as the standard for judging whether the display module has a vertical crosstalk phenomenon, when the brightness ratio is greater than the set ratio, it is determined that the display module has a vertical crosstalk phenomenon; when the brightness ratio is less than or equal to the set ratio, it is determined that the display module does not have a vertical crosstalk phenomenon, avoiding the inaccuracy caused by the subjectivity of using the human eye to judge the vertical crosstalk phenomenon and improving the accuracy of evaluating the voltage threshold.

[0092] Please refer to Figure 17 , in some embodiments, the test method further includes:

[0093] 011: Determine the reference drain current according to the brightness difference, the set ratio and the duration of each frame. The brightness difference is the brightness difference of the target area at the first moment and the second moment. When displaying the preset picture, the source-drain voltage difference of the driving transistor in the target area is the largest within the first moment to the second moment, and the source-drain voltage difference is used to represent the voltage difference between the drain and the source of the driving transistor;

[0094] 012: Determine the current threshold according to the reference drain current and the drain current corresponding to the voltage threshold.

[0095] Specifically, please refer toFigure 18 Step 011 can be implemented by the sixth determination module 110 of the test device 100 according to an embodiment of the present invention, and step 012 can be implemented by the seventh determination module 120 of the test device 100 according to an embodiment of the present invention. That is to say, the sixth determination module 110 can be used to determine a reference drain current according to a luminance difference, a set ratio, and a per-frame duration. The luminance difference is the luminance difference of a target area at a first moment and a second moment. When a preset screen is displayed, the source-drain voltage difference of the driving transistor in the target area is the largest within the first moment to the second moment, and the source-drain voltage difference is used to represent the voltage difference between the drain and the source of the driving transistor; the seventh determination module 120 can be used to determine a current threshold according to the reference drain current and the drain current corresponding to a voltage threshold.

[0096] Among them, it is set that at time T3, the luminance of point A is L under both the preset screen and the L80 gray-scale screen; the luminance difference is the luminance difference of point A under the two screens at time T4. The set luminance difference is ΔL, and the luminance difference and the transmittance difference are approximately proportional, |ΔTr| / Tr = |ΔL| / L; at time T4, the pixel voltage difference of point A under the two screens is ΔV. When |ΔV| is small (such as |ΔV| is less than 0.1 V), the drain-off current Ioff is a constant value, and the transmittance difference and the voltage difference are proportional, that is, |ΔTr| = |ΔV|×C, then |ΔL| = |ΔV|×D, where C and D are constants; according to the capacitor charge and discharge formula:

[0097] |ΔV| = Q / (Cst + Clc) = Ioff×t / (Cst + Clc)

[0098] Among them, Cst is the storage capacitor, Clc is the liquid crystal capacitor, t = 0.5T, and T is the per-frame duration of the display module. Therefore:

[0099]

[0100] Since the human eye perceives the average luminance within a relatively short period of time, and |ΔL| is proportional to the time t, and the set ratio is 2%, so there should be:

[0101]

[0102] It can be simplified to:

[0103]

[0104] When t1 is the maximum value of 0.25T:

[0105]

[0106] Converted to the transmittance difference:

[0107]

[0108] Combined with the Gamma and V-Tr curves (not shown in the figure), when the transmittance Tr = 7.8% at the L80 gray level screen, the constant C can be approximately calculated from the V-Tr curve. At the same time, substituting the values of Cst+Clc and T, the Ioff value can be approximately calculated. This Ioff can be used as the theoretical reference drain current Ioff_spec1. According to the order of magnitude of the reference drain current Ioff_spec1 and the voltage threshold, the current threshold Ioff_spec can be determined. In one embodiment, |ΔV| = 0.035V < 0.1V, then it is approximately considered that Ioff_spec is a fixed value. The reference drain current Ioff_spec1 is 6.2 pA, so the order of magnitude of the current threshold should be in the pA level, and the current threshold can be determined within the pA level. If the order of magnitude of the current threshold determined according to the voltage threshold is not in the pA level, it can be considered that the current threshold is determined incorrectly; at the same time, the gate-off voltage range Vgl_margin can be estimated according to the reference drain current.

[0109] In addition, the reference drain current can be used to determine the setting coefficients for setting the top light brightness and the backlight brightness. Since the reference drain current Ioff_spec1 is small, the test equipment is vulnerable to the influence of air humidity and sample surface stains at this order of magnitude (pA level), resulting in a large error in the measured Ioff. However, the enhancement of the top light can increase the test leakage ratio of the TFT, reducing the influence of this part of the Ioff error; but the continuous increase of the top light will also lead to a weakening of the linear relationship between Ioff and the light intensity. And due to the limited light illumination accuracy of the test device, it is difficult to reduce the top light of the driving transistor to below 1 nit. At the same time, at low light levels, Ioff and the top light brightness are strongly linearly correlated. In one embodiment, the setting coefficient c = 0.55‰, the reference current threshold Ioff_spec1 is 30 pA to 35 pA, the gate-off voltage range can be estimated according to the reference current threshold, and the estimated value of the gate-off voltage range is 1V higher than the measured value, which can be considered close to the measured value. The voltage thresholds and current thresholds measured at three positions of the display module are shown in Table 3.

[0110]

[0111] Table 3

[0112] In this way, according to the brightness difference, the setting ratio, and the duration of each frame, the theoretical reference drain current can be determined, and then according to the reference drain current and the drain current corresponding to the voltage threshold, the current threshold can be determined, so as to provide a judgment standard for the current threshold.

[0113] An embodiment of the present invention provides a test device, which includes one or more processors and a memory. The memory stores a computer program. When the computer program is executed by the processor, the steps of the test method according to any of the above embodiments are implemented.

[0114] Thus, taking the drain current, which is the direct factor causing the vertical crosstalk phenomenon, as a parameter for evaluating the display module, increasing the gate-off voltage of the driving transistor, recording the gate-off voltage at which the vertical crosstalk phenomenon occurs as the voltage threshold, and determining the drain current corresponding to the voltage threshold to obtain the current threshold as the evaluation parameter. Then, performing a reliability test on the display module for a set time, determining the test drain current according to the preset gate-off voltage of the set display module. When the test drain current is less than the current threshold, the set preset gate-off voltage is appropriate, so that the display module will not have the vertical crosstalk phenomenon within the set time, realizing the test of the preset gate-off voltage.

[0115] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by the processor, the steps of the test method according to any of the above embodiments are implemented.

[0116] Thus, taking the drain current, which is the direct factor causing the vertical crosstalk phenomenon, as a parameter for evaluating the display module, increasing the gate-off voltage of the driving transistor, recording the gate-off voltage at which the vertical crosstalk phenomenon occurs as the voltage threshold, and determining the drain current corresponding to the voltage threshold to obtain the current threshold as the evaluation parameter. Then, performing a reliability test on the display module for a set time, determining the test drain current according to the preset gate-off voltage of the set display module. When the test drain current is less than the current threshold, the set preset gate-off voltage is appropriate, so that the display module will not have the vertical crosstalk phenomenon within the set time, realizing the test of the preset gate-off voltage.

[0117] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples" or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. In addition, without conflict, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0118] In addition, the term "connection" should be understood in a broad sense. For example, it may include fixed connection, may also include detachable connection, or integral connection; it may include direct connection, may also be indirectly connected through an intermediate medium, and may further include the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0119] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0120] Any process or method description shown in the flowchart or described in other ways herein can be understood as representing a module, segment, or part of code including one or more executable instructions for implementing a specific logical function or process. And the scope of the preferred embodiments of the present invention includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0121] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A testing method for a display module, characterized in that, The display module includes a driving transistor, and the test method includes: Raise the gate-off voltage of the driving transistor; When the display module exhibits a vertical crosstalk phenomenon, record the gate-off voltage of the target area as the voltage threshold, where the target area is within the display area of the display module; Determine the drain current corresponding to the voltage threshold as the current threshold; Perform a reliability test on the driving transistor for a set time to determine the test drain current according to the preset gate-off voltage of the display module; When the test drain current is less than the current threshold, determine that the display module passes the test.

2. The test method according to claim 1, wherein, The determining the drain current corresponding to the voltage threshold includes: Determine the correspondence between the gate-off current and the drain current of the display module; Determine the current threshold according to the correspondence and the voltage threshold.

3. The test method according to claim 2, wherein The display module includes a backlight layer. Before raising the gate-off voltage of the driving transistor, the test method further includes: Adjust the brightness of the backlight layer to a set backlight brightness; Before determining the correspondence between the gate-off current and the drain current of the display module, the determining the drain current corresponding to the voltage threshold further includes: Apply a top light with a set top light brightness to the driving transistor. The top light is used to irradiate the channel of the driving transistor, and the set top light brightness is the product of the set backlight brightness and a set coefficient.

4. The test method according to claim 1, wherein After performing the reliability test on the driving transistor for a set time, the test method further includes: Determine the variation relationship between the drain-off current and time according to the reliability result of the reliability test; Determine the lifespan of the display module according to the time corresponding to the current threshold in the variation relationship.

5. The test method according to claim 1, characterized in that The performing the reliability test on the driving transistor for a set time includes: Adjust the gate voltage of the driving transistor, the frame duration of the display module, and the scanning range to complete the reliability test on the driving transistor for a set time within a set test time, where the set test time is shorter than the set time.

6. The test method according to claim 1, wherein Before recording the gate-off voltage of the target area as the voltage threshold, the test method further includes: When the brightness ratio is greater than a set ratio, determine that the display module exhibits a vertical crosstalk phenomenon. The brightness ratio is the ratio of the difference between the brightness value of the target area and a set brightness value to the set brightness value.

7. The test method according to claim 6, wherein The test method further includes: Determine a reference drain current according to the brightness difference, the set ratio, and the frame duration. The brightness difference is the brightness difference of the target area at a first moment and a second moment. When displaying a preset image, the source-drain voltage difference of the driving transistor of the target area is the largest within the first moment to the second moment, and the source-drain voltage difference is used to represent the voltage difference between the drain and the source of the driving transistor; Determine the current threshold according to the reference drain current and the drain current corresponding to the voltage threshold.

8. A test device for a display module, characterized in that, The display module includes a driving transistor, and the test device includes: An adjustment module for raising the gate-off voltage of the driving transistor; A recording module, which is configured to record that the gate-off voltage of a target area is a voltage threshold when a vertical crosstalk phenomenon occurs in the display module, and the target area is located within the display area of the display module; A first determination module, which is configured to determine the drain current corresponding to the voltage threshold as a current threshold; A testing module, which is configured to perform a reliability test on the driving transistor for a set time to determine the test drain current of a test target according to the preset gate-off voltage of the display module; A second determination module, which is configured to determine that the display module passes the test when the test drain current is less than the current threshold; 9. A testing device, characterized in that, The testing device includes one or more processors and a memory, and the memory stores a computer program. When the computer program is executed by the processor, the steps of the testing method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, the steps of the testing method according to any one of claims 1 to 7 are implemented.

Images