Display panel aging test method

Abstract

This invention provides a display panel aging test method, which incorporates judgment and calibration steps to determine whether the screened abnormal grayscale is correct and correct erroneous experimental data, thereby finding the true grayscale with the most severe color difference and improving the accuracy of the aging test.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a method for testing the aging of display panels. Background Technology

[0002] Before LCD panels enter the consumer market, they typically undergo multiple aging tests to verify their stability. The test method usually involves keeping the display panel lit for an extended period and measuring the display data after this extended period. This data is then compared to the initial display data, and the stability of the display panel is determined by the fluctuations in the display data over different lighting times.

[0003] However, even if the same experimental method is used in each aging experiment, the results are not the same, which seriously affects the accuracy of the aging experiment. Summary of the Invention

[0004] The purpose of this invention is to provide a display panel aging test method to solve the technical problem of poor accuracy of existing display panel aging test results.

[0005] To achieve the above objectives, the present invention provides a display panel aging test method, which includes the following steps:

[0006] Light up the display panel and measure the display data of the display panel; obtain the color difference value of the display panel when it is initially lit and after a long period of lighting; screen out abnormal gray levels based on the color difference value; determine whether the screened abnormal gray levels are correct; when the screened abnormal gray levels are incorrect, calibrate the abnormal gray levels.

[0007] Furthermore, the step of determining whether the screened abnormal grayscale values ​​are correct includes the following steps:

[0008] Set a standard difference range; obtain the first contrast ratio of the display panel when it is initially lit; obtain the second contrast ratio of the display panel after it has been lit for a long time; compare the first contrast ratio and the second contrast ratio.

[0009] When the increase in contrast between the first and second contrast ratios is within the standard difference range, the screened abnormal grayscale is determined to be correct. When the increase in contrast between the first and second contrast ratios exceeds the standard difference range, the screened abnormal grayscale is determined to be incorrect.

[0010] Furthermore, the step of obtaining the first contrast ratio of the display panel when it is initially lit includes the following steps:

[0011] When the display panel is initially lit, the first bright state brightness and the first dark state brightness of the display panel are obtained; the first bright state brightness and the first dark state brightness are substituted into the contrast ratio formula to calculate the first contrast ratio.

[0012] Furthermore, the step of obtaining the second contrast ratio of the display panel after prolonged illumination includes the following steps:

[0013] After the display panel has been lit for an extended period of time, the second bright state brightness and the second dark state brightness of the display panel are obtained; the second bright state brightness and the second dark state brightness are then substituted into the contrast ratio formula to calculate the second contrast ratio.

[0014] Furthermore, the contrast ratio formula is: Contrast Ratio = Brightness in Bright State / Brightness in Dark State.

[0015] Furthermore, the standard difference ranges from -20% to 20%.

[0016] Furthermore, the step of calibrating the abnormal grayscale includes the following steps:

[0017] Obtain the reference tristimulus values ​​and the abnormal tristimulus values ​​that need to be corrected for the display panel; substitute the reference tristimulus values ​​and the abnormal tristimulus values ​​into the correction formula to calculate the correct chromaticity data; obtain the correct abnormal grayscale after correction using the correct chromaticity data.

[0018] Furthermore, the step of obtaining the reference tristimulus values ​​and the abnormal tristimulus values ​​of each grayscale of the display panel includes the following steps:

[0019] Obtain the tristimulus values ​​X, Y, and Z of each grayscale level when the display panel is initially lit and after the display panel has been lit for a long time; obtain the first contrast ratio of the display panel when it is initially lit; obtain the second contrast ratio of the display panel after the display panel has been lit for a long time; compare the first contrast ratio and the second contrast ratio.

[0020] For contrast ratios with higher values, the tristimulus values ​​of the corresponding dark-state image are used as the baseline tristimulus values. For contrast ratios with lower values, the tristimulus values ​​of each grayscale level are used as the aberrant tristimulus values.

[0021] Furthermore, the step of obtaining the tristimulus values ​​X, Y, and Z of each grayscale level during initial illumination and after prolonged illumination includes the following steps:

[0022] The brightness Lv, chromaticity x, and chromaticity y of each grayscale of the display panel are obtained when it is initially lit and after a long period of lighting. The tristimulus values ​​of each grayscale of the display panel are calculated using the tristimulus value calculation formula.

[0023] The formula for calculating the tristimulus value includes:

[0024] X = (Lv × x) / y;

[0025] Y = Lv;

[0026] Z = [Lv × (1 - xy)] / y.

[0027] Furthermore, the baseline tristimulus value includes X 基准 Y 基准 and Z 基准 The abnormal tristimulus values ​​include X. 异常 Y 异常 and Z 异常 The chromaticity data includes chromaticity values ​​x and chromaticity values ​​y.

[0028] The correction formula includes:

[0029] x=(X 异常 –X 基准 ) / (X 异常 +Y 异常 +Z 异常 -X 基准 -Y 基准 -Z 基准 );

[0030] y = (Y 异常 –Y 基准 ) / (X 异常 +Y 异常 +Z 异常 -X 基准 -Y 基准 -Z 基准 ).

[0031] Beneficial effects: The display panel aging test method of the present invention can determine whether the screened abnormal grayscale is correct, and can also correct the relevant display data, thereby finding the true grayscale with the most serious color difference, and thus improving the accuracy of the aging test. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart illustrating the display panel aging test method in an embodiment of the present invention.

[0034] Figure 2This is a flowchart illustrating the abnormal grayscale determination method in an embodiment of the present invention;

[0035] Figure 3 This is a flowchart illustrating the abnormal grayscale calibration method in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram illustrating the difference in chromaticity values ​​y of white points at various gray levels after the experimental panel has been lit for a long time in an embodiment of the present invention.

[0037] Figure 5 This is a schematic diagram of the curves of the chromaticity values ​​y of each grayscale white point when the experimental panel is initially lit up in an embodiment of the present invention.

[0038] Figure 6 This is a schematic diagram of the curves of the white point chromaticity value y before calibration of each grayscale level on the experimental panel in this embodiment of the invention after 48 hours of illumination.

[0039] Figure 7 This is a schematic diagram of the curves of the white point chromaticity value y after each grayscale calibration of the experimental panel in an embodiment of the present invention after being lit for 48 hours.

[0040] Figure 8 This is a schematic diagram illustrating the difference fluctuation of the white point chromaticity value y at each color level after calibration in an embodiment of the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0042] This invention provides an aging test method for a display panel, used to detect the aging condition of the display panel after prolonged lamp operation. The aging test method includes a detection method for abnormal grayscale, a judgment method, and a calibration method. The detection method is used to initially screen out grayscale levels that have developed color differences after aging, as well as the abnormal grayscale levels with the most severe color differences. The judgment method is used to determine whether the screened abnormal grayscale levels are correct. If the screened abnormal grayscale levels are incorrect, the calibration method can correct the erroneous colorimetric data and re-screen out the correct abnormal grayscale levels.

[0043] Specifically, the process of the aging test method for the display panel is as follows: Figure 1 As shown, it includes the following specific steps:

[0044] Step S100) Light up the display panel and measure the relevant display data of the display panel:

[0045] Set the aging test duration for the display panel and turn it on. After turning on the display panel, measure the display data of the display panel at the initial lighting stage.

[0046] The display panel is kept lit continuously. Once the lighting duration of the display panel meets the aging test duration, the display data of the display panel is measured again after the aging test duration.

[0047] Specifically, the display data includes chromaticity data and luminance data for each grayscale level, as well as tristimulus values. The chromaticity data includes chromaticity values ​​x and chromaticity values ​​y.

[0048] Step S200) The grayscale values ​​that cause severe color differences after the display panel ages are screened out using an abnormal grayscale detection method. The detection method includes steps S210-220.

[0049] Step S210) Obtain the color difference value of the display panel when it is initially lit up and after a long period of lighting up:

[0050] In the display data measured in step S100, the chromaticity values ​​y of each gray level of the display panel when it is initially lit are obtained, and the chromaticity values ​​y of each gray level of the display panel after it has been lit for a long time are obtained.

[0051] The chromaticity difference between the initial lighting and the long-term lighting of the display panel is obtained by subtracting the chromaticity value y of each gray level from the chromaticity value y of each gray level when the display panel is initially lit.

[0052] Step S220) Based on the color difference value, screen out grayscale values ​​that have developed severe color differences after aging:

[0053] Obtain the chromaticity difference values ​​of each grayscale obtained through calculation in step S210, and compare the chromaticity difference values ​​between each grayscale. Among them, the grayscale with the largest chromaticity difference value is the abnormal grayscale with the most severe chromaticity difference after aging.

[0054] Step S300) Determine whether the screened abnormal grayscale levels are correct using an abnormal grayscale determination method. The process of the determination method is as follows: Figure 2 As shown, it includes steps S310-S330.

[0055] Step S310) Set the standard difference range:

[0056] A standard difference range is set for the contrast ratio of the display panel when it is initially lit up and after prolonged lighting. Preferably, the standard difference range is -20% to 20%.

[0057] Step S320) Obtain the contrast data of the display panel under different lighting durations:

[0058] In the display data measured in step S100, the first bright state brightness and the first dark state brightness of the display panel when it is initially lit, and the second bright state brightness and the second dark state brightness of the display panel after a long period of lighting are obtained.

[0059] Substituting the first bright state brightness and the first dark state brightness into the contrast ratio formula, the first contrast ratio of the display panel when it is initially lit is calculated.

[0060] By substituting the second bright state brightness and the second dark state brightness into the contrast ratio formula, the second contrast ratio of the display panel after a long period of illumination is calculated.

[0061] Wherein, the first bright state brightness is the brightness of the white screen when the display panel is initially lit, the first dark state brightness is the brightness of the black screen when the display panel is initially lit, the second bright state brightness is the brightness of the white screen after the display panel has been lit for a long time, and the second dark state brightness is the brightness of the black screen after the display panel has been lit for a long time. The contrast ratio formula is: Contrast Ratio = Bright State Brightness / Dark State Brightness.

[0062] Step S330) Determine whether the abnormal grayscale values ​​screened out are correct based on the contrast data:

[0063] Compare the magnitudes of the first contrast ratio and the second contrast ratio, and calculate the increase between them. When the increase between the first contrast ratio and the second contrast ratio is within the standard difference range, the abnormal grayscale detected in step S200 is correct, and its relevant data can be directly used. When the increase between the first contrast ratio and the second contrast ratio exceeds the standard difference range, the abnormal grayscale detected in step S200 is incorrect and needs to be corrected.

[0064] Step S400) Corrects abnormal gray levels and their related data using an abnormal gray level calibration method. The calibration method is as follows: Figure 3 As shown, it includes steps S410-S430.

[0065] Step S410) Obtain the grayscale tristimulus values ​​of the display panel at different illumination times:

[0066] In the display data measured in step S100, the tristimulus values ​​X, Y, and Z of each grayscale level are obtained when the display panel is initially lit and after the display panel has been lit for a long time. The tristimulus values ​​can be directly measured using a measuring tool, or obtained through steps S411-S412:

[0067] Step S411) From the display data measured in step S100, obtain the brightness and chromaticity data of each gray level of the display panel when it is initially lit and after a long period of lighting.

[0068] Step S412) Substitute the brightness (Lv) and chromaticity data of each gray level into the tristimulus value calculation formula to calculate the tristimulus values ​​of each gray level of the display panel when it is initially lit and after a long period of lighting.

[0069] The formula for calculating the tristimulus values ​​includes:

[0070] X = (Lv × x) / y;

[0071] Y = Lv;

[0072] Z = [Lv × (1 - xy)] / y.

[0073] Step S420) Correct abnormal chromaticity data using tristimulus values ​​and correction formulas:

[0074] Obtain the first contrast ratio and the second contrast ratio calculated in step S300, and compare the first contrast ratio and the second contrast ratio. The contrast ratio with a larger value corresponds to the baseline tristimulus value for the dark state image; the contrast ratio with a smaller value corresponds to the aberrant tristimulus values ​​for each grayscale level. Using the baseline tristimulus value as the correction benchmark for the chromaticity data, correct the aberrant tristimulus values ​​to obtain the corrected normal tristimulus values.

[0075] According to the contrast ratio formula, a low contrast ratio means increased brightness in dark areas. Low grayscale images will increase brightness beyond the existing low-level brightness, leading to data anomalies. Therefore, it is necessary to correct the grayscale data corresponding to a low contrast ratio to avoid affecting low-grayscale images.

[0076] The abnormal tristimulus values ​​for each grayscale level are obtained, and then corrected using a tristimulus value correction formula to obtain the normal tristimulus values ​​for each grayscale level. The reference tristimulus values ​​include X... 基准 Y 基准 and Z 基准 The abnormal tristimulus values ​​include X 异常 Y 异常 and Z 异常The normal tristimulus values ​​include X 正常 Y 正常 and Z 正常 .

[0077] The tristimulus value correction formula includes:

[0078] X 正常 =X 异常 -X 基准 ;

[0079] Y 正常 =Y 异常 -Y 基准 ;

[0080] Z 正常 =Y 异常 -Y 基准 .

[0081] The conversion formula between chromaticity data and tristimulus values ​​is known to be:

[0082] x = X / (X + Y + Z);

[0083] y = Y / X + Y + Z.

[0084] The correct chromaticity data is:

[0085] x = X 正常 / (X 正常 +Y 正常 +Z 正常 );

[0086] y = Y 正常 / (X 正常 +Y 正常 +Z 正常 ).

[0087] Furthermore, by combining the correction formula for the tristimulus values ​​with the conversion formula mentioned above, we can obtain the correction formula for the chromaticity data:

[0088] x=(X 异常 –X 基准 ) / (X 异常 +Y 异常 +Z 异常 -X 基准 -Y 基准 -Z 基准 );

[0089] y = (Y 异常 –Y 基准 ) / (X 异常 +Y 异常 +Z 异常 -X 基准 -Y 基准 -Z基准 ).

[0090] By substituting the reference tristimulus value and the abnormal tristimulus value of each gray level into the correction formula of the above chromaticity data, the correct chromaticity data after correction for each gray level can be obtained.

[0091] Step S430) Use the corrected chromaticity data to recalculate the chromaticity difference of each gray level of the display panel when it is initially lit up and after a long period of lighting up, and use the chromaticity difference calculated this time to screen out gray levels that have serious color differences after aging.

[0092] Specifically, this embodiment of the invention provides an experimental panel, which undergoes an aging test using the aforementioned aging test method. In this experiment, the aging test duration for the experimental panel is 48 hours.

[0093] The experimental panel was turned on, and the display data of the experimental panel was measured at the initial lighting time and after 48 hours of lighting.

[0094] From the measured display data, obtain the chromaticity values ​​y of each grayscale level of the experimental panel when it is initially lit and the chromaticity values ​​y of each grayscale level of the experimental panel after 48 hours of lighting. Calculate the difference between the white point chromaticity values ​​y of each grayscale level when it is initially lit and the white point chromaticity values ​​y of each grayscale level after 48 hours of lighting, and plot the results as shown below. Figure 4 The graph shows the fluctuation of the white point chromaticity value y. (Based on...) Figure 4 It can be seen that the maximum color difference occurs at level 0.

[0095] The first bright state brightness and the first dark state brightness of the experimental panel when it is initially lit, and the second bright state brightness and the second dark state brightness of the experimental panel after 48 hours of lighting, are obtained, and the first contrast ratio of the experimental panel when it is initially lit and the second contrast ratio of the experimental panel after 48 hours of lighting are calculated respectively.

[0096] Specifically, the relevant brightness and contrast data of the experimental panel are shown in Table 1.

[0097] When initially lit After 48 hours of being lit Brightness 345.2 343.6 Dark state brightness 0.085 0.212 Contrast 4061 1621

[0098] Table 1

[0099] As shown in Table 1, the first contrast ratio is 4061 and the second contrast ratio is 1621. The increase between the first contrast ratio and the second contrast ratio is -60%, which exceeds the standard difference range of -20% to 20%, so it needs to be corrected.

[0100] Based on the contrast data above, it can be seen that the first contrast ratio is greater than the second contrast ratio in chromaticity. Therefore, the tristimulus value of the dark state 0th level corresponding to the first contrast ratio is the baseline tristimulus value, while the tristimulus values ​​of each gray level corresponding to the second contrast ratio are abnormal tristimulus values. That is, it is necessary to correct the abnormal original chromaticity data of the experimental panel after it has been lit for 48 hours using the corresponding correction formula, and to obtain the correct new chromaticity data.

[0101] Specifically, in this embodiment of the invention, the datasets of grayscale chromaticity values ​​y before and after calibration of the experimental panel at the initial lighting and 48 hours after lighting are combined and plotted as curves. Figure 5-7 .according to Figure 6-7 It can be seen that the chromaticity value y of the experimental panel was effectively corrected after being lit for 48 hours.

[0102] Based on the corrected chromaticity data, the differences between the chromaticity values ​​y of each grayscale level at the initial illumination and the chromaticity values ​​y of each grayscale level after 48 hours of illumination are recalculated and plotted as follows: Figure 8 The diagram shows the variation fluctuations. According to... Figure 8 As can be seen from the content, after the experimental panel was lit for a long time, the actual maximum color difference did not occur at level 0, but at around level 20.

[0103] The display panel aging test method provided in this embodiment of the invention incorporates a method for judging abnormal grayscale and a calibration method. The judgment method determines whether the screened abnormal grayscale is correct, and the calibration method obtains accurate display data and identifies the true grayscale with the most severe color difference, thereby improving the accuracy of the aging test.

[0104] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A method for testing the aging of a display panel, characterized in that, Includes the following steps: Turn on the display panel and measure the display data of the display panel; Obtain the color difference between the display panel when it is initially lit and after a long period of lighting; Abnormal gray levels are screened out based on the color difference values; Determine whether the abnormal grayscale values ​​identified during screening are correct; When the abnormal grayscale detected during screening is incorrect, the abnormal grayscale is calibrated. The abnormal grayscale calibration step includes the following steps: Obtain the baseline tristimulus values ​​and the abnormal tristimulus values ​​that need to be corrected for the display panel; The correct chromaticity data is calculated by substituting the reference tristimulus value and the abnormal tristimulus value into the correction formula; Corrected aberration grayscale is obtained by using correct chroma data; The steps for obtaining the reference tristimulus values ​​and abnormal tristimulus values ​​for each grayscale level of the display panel include the following steps: Obtain the tristimulus values ​​X, Y, and Z of each grayscale level when the display panel is initially lit and after the display panel has been lit for a long time; The display data includes the first bright state brightness and the first dark state brightness of the display panel when it is initially lit, and the second bright state brightness and the second dark state brightness of the display panel after a long period of lighting. Substitute the first bright state brightness and the first dark state brightness into the contrast formula to calculate the first contrast ratio of the display panel when it is initially lit. By substituting the second bright state brightness and the second dark state brightness into the contrast ratio formula, the second contrast ratio of the display panel after a long period of illumination is calculated.

2. The display panel aging test method as described in claim 1, characterized in that, The process of obtaining the tristimulus values ​​X, Y, and Z at each grayscale level during initial illumination and after prolonged illumination includes the following steps: The brightness Lv, chromaticity value x, and chromaticity value y of each grayscale level of the display panel are obtained when it is initially lit and after a long period of lighting. The tristimulus values ​​of the display panel at each gray level were calculated using the tristimulus value calculation formula, both when initially lit and after prolonged lighting.

3. The display panel aging test method as described in claim 2, characterized in that, The step of obtaining the reference tristimulus values ​​and abnormal tristimulus values ​​of each grayscale of the display panel also includes the following steps: Compare the first contrast ratio and the second contrast ratio; For contrast values ​​that are relatively large, the tristimulus values ​​of the corresponding dark-state image are used as the reference tristimulus values. For contrast values ​​that are relatively small, the tristimulus values ​​of each corresponding gray level are taken as the abnormal tristimulus values.

4. The display panel aging test method as described in claim 3, characterized in that, The calibration of the abnormal grayscale step also includes: correcting the abnormal chromaticity data using the tristimulus value calculation formula and correction formula.

5. The display panel aging test method as described in claim 4, characterized in that, The formula for calculating the tristimulus value includes: X = (Lv × x) / y; Y=Lv; Z = [Lv × (1 - xy)] / y.

6. The display panel aging test method as described in claim 5, characterized in that, The reference tristimulus values ​​include X reference, Y reference and Z reference, the abnormal tristimulus values ​​include X abnormal, Y abnormal and Z abnormal, and the chromaticity data includes chromaticity value x and chromaticity value y; The correction formula includes: x = (X anomaly – X baseline) / (X anomaly + Y anomaly + Z anomaly - X baseline - Y baseline - Z baseline); y = (Y anomaly – Y baseline) / (X anomaly + Y anomaly + Z anomaly - X baseline - Y baseline - Z baseline).

7. The display panel aging test method as described in claim 6, characterized in that, The corrected chromaticity data for each gray level is obtained by substituting the reference tristimulus value and the abnormal tristimulus value for each gray level into the correction formula of the above chromaticity data.

8. The display panel aging test method as described in claim 7, characterized in that, After obtaining the correct chromaticity data for each grayscale level, the method further includes: using the corrected chromaticity data to recalculate the chromaticity difference of each grayscale level of the display panel when it is initially lit up and after a long period of lighting up, and using the chromaticity difference calculated this time to screen out grayscale levels that have produced serious color differences after aging.

9. The display panel aging test method as described in claim 8, characterized in that, The step of screening out grayscales with severe color difference after aging by using the calculated color difference value includes: calculating the color difference value of each grayscale and comparing the color difference values ​​between each grayscale, wherein the grayscale with the largest color difference value is the abnormal grayscale with the most severe color difference after aging.

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