Method for one-stop brightness correction and local resistance potential drop compensation of organic light emitting diode panel

Abstract

A method for one-stop brightness correction and local resistance potential drop compensation of an organic light emitting diode panel includes steps of: (A) taking brightness information of each sub-pixel of the organic light emitting diode panel at a plurality of predetermined gray scales; (B) calculating brightness correction compensation values of each gray scale, and selecting and storing a brightness correction compensation value of a specific gray scale; (C) calculating local resistance potential drop compensation parameters of each sub-pixel by subtracting the brightness correction compensation value of the specific gray scale stored from the brightness correction compensation values of each gray scale; and (D) according to local resistance potential drop compensation, fusing the local resistance potential drop compensation parameters of each sub-pixel at each gray scale calculated in step (C) to obtain local resistance potential drop compensation parameters of each region distinguished by the organic light emitting diode panel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic light emitting diode panels, and in particular to a method for one-stop brightness correction and local IR drop compensation of an organic light emitting diode panel. BACKGROUND

[0002] Organic light emitting diode (OLED) panels have a lot of variations between sub-pixels in the manufacturing process, resulting in random non-uniformity of panel brightness (Mura phenomenon), which is usually presented as sandy Mura and has a low yield. To solve this problem, an optical compensation method is used, i.e., Demura is used to remove the non-uniformity of the brightness of the panel. Since the OLED panel is powered by a power chip, the distance of the power supply trace is different, resulting in different degrees of IR drop of the voltage (ELVDD) supplied to each sub-pixel, which leads to progressive non-uniformity of the in-panel brightness, and local IR drop compensation (LIRC) is needed.

[0003] The aforementioned Demura needs to obtain the brightness information of all sub-pixel units when the OLED panel displays different gray scales of each color (R / G / B), and analyze the brightness non-uniformity to obtain and store the Demura compensation values of each color corresponding to different gray scales of each sub-pixel unit. However, since the amount of data of the aforementioned Demura compensation values is huge, it is generally impossible to store Demura compensation values of all gray scales, and only Demura compensation values of each color corresponding to a certain specific gray scale of each sub-pixel unit are stored, and Demura compensation values of the remaining gray scales are calculated for brightness correction.

[0004] The aforementioned LIRC is to measure the brightness of each position in the OLED panel by an optical instrument (such as CA-410) in the OLED production process to establish a model of local IR drop and establish compensation-related parameters. For example, each OLED panel is divided into 2x3=6 regions, and the optical instrument measures the brightness information of 3 colors (R / G / B), 4 gray scales (64 / 128 / 192 / 255), and 12 images of B64 / B128 / B192 / B255 in 6 (=2x3) regions of the OLED panel, i.e., a total of 12x6=72 regions of brightness information need to be measured, and the brightness information of the 72 regions is stored to establish the LIRC model and the LIRC compensation parameters for local IR drop compensation.

[0005] As the requirements of panel factory and mobile phone factory for OLED in-plane uniformity are increasingly stringent, the compensation partition number of LIRC is also increased, which can be up to hundreds of regions. In order to obtain the luminance information of all regions of all test colors, a total of thousands of position points may need to be measured, which is extremely time-consuming and seriously affects the production speed of the panel.

[0006] Furthermore, in the data path of the driving chip, LIRC is processed before Demura, so in the existing OLED production process, the operation process of LIRC and Demura is to first perform LIRC to measure the luminance of each partition of the required test color of LIRC, calculate the compensation parameters of LIRC, and perform LIRC compensation; and then perform Demura compensation based on the already compensated in-plane luminance non-uniformity of the OLED panel.

[0007] Since the aforementioned Demura and LIRC need to be photographed by a CCD camera and measured by an optical instrument at two process stations, it takes a long time and seriously affects the production speed of the panel.

[0008] Therefore, there are still many deficiencies in the existing display panel process, and it is necessary to improve them. SUMMARY

[0009] The purpose of the present application is to provide a one-stop luminance correction and local resistance potential drop compensation method for an organic light-emitting diode panel, which integrates local resistance potential drop compensation and luminance correction in the same station, avoiding the increase of production equipment and time cost and effectively solving the two luminance non-uniformity problems of the organic light-emitting diode panel.

[0010] According to a feature of the present application, a one-stop luminance correction and local resistance potential drop compensation method for an organic light-emitting diode panel is provided, which includes the following steps: (A) for each color, photographing the luminance information of each sub-pixel of the organic light-emitting diode panel at multiple predetermined gray scales; (B) for each color, calculating the luminance correction compensation value of each gray scale, and selecting and storing the luminance correction compensation value of a specific gray scale; (C) for each color, subtracting the luminance correction compensation value of the specific gray scale stored from the luminance correction compensation value of each gray scale to calculate the local resistance potential drop compensation parameters of each sub-pixel; and (D) for each color, according to the local resistance potential drop compensation, the local resistance potential drop compensation parameters of each sub-pixel at each gray scale calculated in step (C) are integrated to obtain the local resistance potential drop compensation parameters of each region. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 A flow of a method of brightness correction and local IR drop compensation for a one-stop Organic Light Emitting Diode (OLED) panel is shown.

[0012] Figure 2 A structure of an OLED panel is shown schematically.

[0013] Figure 3 Brightness information of each sub-pixel unit of an OLED panel at a plurality of predetermined gray scales is shown schematically.

[0014] Figure 4 Local IR drop compensation parameters of a plurality of regions of an OLED panel are shown schematically.

[0015] Steps S11-S14

[0016] An OLED panel 20

[0017] A pixel unit 21

[0018] A sub-pixel unit 201

[0019] A region 41 DETAILED DESCRIPTION

[0020] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the implementation of the present application and should not be used to limit the present application.

[0021] Figure 1 A flow of a method of brightness correction and local IR drop compensation for a one-stop Organic Light Emitting Diode (OLED) panel is shown. In the method of the present application, local IR drop compensation (LIRC) and brightness correction (Demura) are integrated and performed at the same station, that is, Figure 1 Steps (A) to (D) of the present application are performed at the same Demura station to obtain Demura compensation values and LIRC compensation parameters for brightness non-uniformity compensation and LIRC compensation of an OLED panel, wherein, for example, Figure 2As shown, an OLED panel 20 has a plurality of pixel units 21, each pixel unit 21 including at least one color sub-pixel unit 201. In one embodiment and in the following description of the present invention, each pixel unit 21 of the OLED panel 20 includes a red (R) sub-pixel unit 201, a green (G) sub-pixel unit 201 and a blue (B) sub-pixel unit 201. That is, the color displayed by the pixel unit 21 of the OLED panel 20 is composed of the three colors R / G / B. However, the present invention is not limited to this arrangement of sub-pixels. In other embodiments, the sub-pixel units in the above-mentioned pixel unit may also be arranged in different orders.

[0022] like Figure 1 As shown, in step S11, for each of the three colors R / G / B, the brightness information of each sub-pixel unit 201 of the OLED panel 20 at multiple predetermined gray levels is captured by a CCD camera. Taking an 8-bit color depth display as an example, the multiple predetermined gray levels are, for example, four gray levels: level 64, level 128, level 192, and level 255. Therefore, as... Figure 3 As shown, step S11 involves capturing the brightness information of sub-pixel units 201 of 12 images at the Demura site using a CCD camera, including images with 3 colors (R / G / B) and 4 gray levels (64 / 128 / 192 / 255), namely R64 / R128 / R192 / R255, G64 / G128 / G192 / G255, and B64 / B128 / B192 / B255.

[0023] Secondly, in step S12, for each of the three colors R / G / B, based on the brightness information of each sub-pixel 201 of the OLED panel 20 at multiple predetermined gray levels captured in step S11, and analyzing the brightness unevenness, the Demura compensation value for each gray level is calculated, and the Demura compensation value of a specific gray level is selected and stored in the flash memory. This specific gray level is the one that is considered optimal after brightness analysis. In the example shown in step S11 above, it is based on... Figure 3Demura compensation values for each gray scale (64 / 128 / 192 / 255), specifically, for each gray scale (64 / 128 / 192 / 255), a Demura compensation value for red (Demura_comR), a Demura compensation value for green (Demura_comG), and a Demura compensation value for blue (Demura_comB) are calculated; and a Demura compensation value for a specific gray scale (64) is selected from the gray scales (64 / 128 / 192 / 255) and stored in the flash memory, the specific gray scale Demura compensation value includes a specific gray scale Demura compensation value for red (Demura_comR_sp_scale), a specific gray scale Demura compensation value for green (Demura_comG_sp_scale), and a specific gray scale Demura compensation value for blue (Demura_comB_sp_scale). The relationship between the Demura compensation values obtained by this step S12 and the display data values is as follows:

[0024] R' = R + Demura_comR;

[0025] G' = G + Demura_comG;

[0026] B' = B + Demura_comB; (Formula 1)

[0027] wherein R / G / B are original red / green / blue display data values to be displayed by the red / green / blue sub-pixel units 201, Demura_comR / Demura_comG / Demura_comB are the stored or calculated Demura compensation values for red / green / blue, and R' / G' / B' are the red / green / blue display data values after Demura compensation.

[0028] Next, in step S13, for each of the three colors of R / G / B, the stored specific gray scale Demura compensation value is subtracted from the Demura compensation value for each gray scale to calculate offset value parameters for LIRC compensation for each sub-pixel, wherein LIRC is used to divide the OLED panel 20 into multiple regions and measure the luminance information of each region of the OLED panel 20 at multiple predetermined gray scales for each color. Step S13 uses the luminance information of each sub-pixel 201 of the OLED panel 20 at multiple predetermined gray scales photographed in step S11 and the Demura compensation values for each gray scale calculated in step S12 to calculate the LIRC compensation parameters for each sub-pixel 201.

[0029] Since the brightness unevenness of the OLED panel 20 is actually compensated completely with the relationship of the display data value by Demura and LIRC, it is:

[0030] R' = R + LIRC_offsetR + Demura_comR_sp_scale;

[0031] G' = G + LIRC_offsetG + Demura_comG_sp_scale;

[0032] B' = B + LIRC_offsetB + Demura_comB_sp_scale; (Formula 2)

[0033] Wherein, R / G / B is the original red / green / blue display data value to be displayed by the red / green / blue sub-pixel unit 201, LIRC_offsetR / LIRC_offsetG / LIRC_offsetB is the LIRC compensation parameter of red / green / blue, Demura_comR_sp_scale / Demura_comG_sp_scale / Demura_comB_sp_scale is the specific gray scale Demura compensation value of red / green / blue, and R' / G' / B' is the red / green / blue display data value after LIRC compensation. Comparing Formula 1 with Formula 2, it can be obtained that:

[0034] Demura_comR = LIRC_offsetR + Demura_comR_sp_scale;

[0035] Demura_comG = LIRC_offsetG + Demura_comG_sp_scale;

[0036] Demura_comB = LIRC_offsetB + Demura_comB_sp_scale;

[0037] That is:

[0038] LIRC_offsetR = Demura_comR - Demura_comR_sp_scale;

[0039] LIRC_offsetG = Demura_comG - Demura_comG_sp_scale;

[0040] LIRC_offsetB = Demura_comB - Demura_comB_sp_scale;

[0041] Therefore, the LIRC compensation parameter of each sub-pixel 201 is equal to the Demura compensation value of each gray scale minus the Demura compensation value of the specific gray scale stored. For example, assuming that Demura stores the Demura compensation value of the 64th gray scale, the LIRC compensation parameter of the 128th gray scale of each sub-pixel of the OLED panel 20 can be obtained:

[0042] LIRC_offsetR

[128] = Demura_comR

[128] - Demura_comR

[64] ;

[0043] LIRC_offsetG

[128] = Demura_comG

[128] - Demura_comR

[64] ;

[0044] LIRC_offsetB

[128] = Demura_comB

[128] - Demura_comR

[64] ;

[0045] wherein LIRC_offsetR

[128] / LIRC_offsetG

[128] / LIRC_offsetB

[128] is the LIRC compensation parameter of the 128th gray scale of red / green / blue, Demura_comR

[128] / Demura_comG

[128] / Demura_comB

[128] is the Demura compensation value of the 128th gray scale of red / green / blue, and Demura_comR

[64] / Demura_comG

[64] / Demura_comB

[64] is the Demura compensation value of the 64th gray scale of red / green / blue.

[0046] Therefore, the R64 / R128 / R192 / R255, G64 / G128 / G192 / G255, and B64 / B128 / B192 / B255 full sub-pixel brightness information obtained by the Demura station in step S11 with the CCD camera is the compensation parameter corresponding to a plurality of predetermined gray scales (64 / 128 / 192 / 255) that LIRC needs to store, and the LIRC compensation value of each sub-pixel required can be obtained by one-step LIRC and Demura.

[0047] Finally, in step S14, for each color of R / G / B, the LIRC compensation parameter of each region of the OLED panel 20 is obtained by fusing the LIRC compensation parameter of each sub-pixel at each gray scale calculated in step S13, such as Figure 4As shown, since step S13 is to obtain the LIRC compensation parameters of each sub-pixel 201 of each color, and the LIRC needs to store the LIRC compensation parameters of the plurality of regions 41 of the OLED panel 20, the LIRC compensation parameters of the sub-pixels 201 belonging to the same region 41 at each gray scale are averaged to obtain the LIRC compensation parameters of the plurality of regions 41 of the OLED panel 20.

[0048] As known from the above description, the present application can obtain the brightness information of all the sub-pixels on the whole surface by the shooting of the Demura station, which can be used to calculate the brightness information corresponding to the LIRC partition, which is flexible enough to be applicable to different number of LIRC partitions without re-measurement. Therefore, unlike the prior art, the present application does not need double stations to process the brightness unevenness problem of the OLED panel, and can avoid the increase of production equipment and time cost.

[0049] The above embodiments are only examples for convenience of illustration, and the scope of the right claimed by the present application should be subject to the description of the claims, and is not limited to the above embodiments.

Claims

1. A method for one-stop brightness correction and local resistance potential drop compensation of an organic light-emitting diode (OLED) panel, wherein the OLED panel has a plurality of pixel units, each pixel unit comprising at least one color sub-pixel unit, characterized in that, The method includes the following steps: (A) For each color, capture the brightness information of each sub-pixel of the organic light-emitting diode panel at multiple predetermined gray levels; (B) For each color, calculate the brightness correction compensation value for each gray level, and select and store the brightness correction compensation value for a specific gray level. (C) For each color, subtract the stored brightness correction compensation value for that specific grayscale from the brightness correction compensation value for each grayscale level to calculate the local resistance potential drop compensation parameter for each sub-pixel; and (D) For each color, based on the local resistance potential drop compensation, the local resistance potential drop compensation parameters of each sub-pixel at each gray level calculated in step (C) are fused to obtain the local resistance potential drop compensation parameters of each region in the multiple regions distinguished by the organic light-emitting diode panel.

2. The method for one-stop brightness correction and local resistance potential drop compensation of an organic light-emitting diode panel as described in claim 1, characterized in that, In step (A), a CCD camera is used to capture the brightness information of each sub-pixel of the organic light-emitting diode panel at multiple predetermined gray levels.

3. The method for one-stop brightness correction and local resistance potential drop compensation of an organic light-emitting diode panel as described in claim 1, characterized in that, Each pixel unit contains a red sub-pixel unit, a green sub-pixel unit, and a blue sub-pixel unit.

4. The method for one-stop brightness correction and local resistance potential drop compensation of an organic light-emitting diode panel as described in claim 3, characterized in that, Step (B) involves calculating the luminance correction compensation value for red, green, and blue for each grayscale level, and the relationship between these luminance correction compensation values ​​and the display data values ​​is as follows: R' = R + Demura_comR; G' = G + Demura_comG; B' = B + Demura_comB; In this context, R / G / B represents the original red / green / blue display data values ​​to be displayed by the red / green / blue sub-pixel units, Demura_comR / Demura_comG / Demura_comB represents the brightness correction compensation values ​​for red / green / blue, and R' / G' / B' represents the red / green / blue display data values ​​after brightness correction compensation.

5. The method for one-stop brightness correction and local resistance potential drop compensation of an organic light-emitting diode panel as described in claim 4, characterized in that, The local resistance potential drop compensation parameters for each sub-pixel are obtained according to the following formula: LIRC_offsetR=Demura_comR-Demura_comR_sp_scale; LIRC_offsetG=Demura_comG-Demura_comG_sp_scale; LIRC_offsetB=Demura_comB-Demura_comB_sp_scale; Among them, LIRC_offsetR / LIRC_offsetG / LIRC_offsetB are the local resistance potential drop compensation parameters for red / green / blue, and Demura_comR_sp_scale / Demura_comG_sp_scale / Demura_comB_sp_scale are the specific grayscale brightness correction compensation values ​​for red / green / blue.

6. The method for one-stop brightness correction and local resistance potential drop compensation of an organic light-emitting diode panel as described in claim 4, characterized in that, In step (D), the local resistance potential drop compensation parameters of sub-pixels belonging to the same region at each gray level are averaged to obtain the local resistance potential drop compensation parameters of multiple regions of the organic light-emitting diode surface.

7. The method for one-stop brightness correction and local resistance potential drop compensation of an organic light-emitting diode panel as described in claim 1, characterized in that, Steps (A) through (D) are performed at the brightness correction station.

8. The method for one-stop brightness correction and local resistance potential drop compensation of an organic light-emitting diode panel as described in claim 1, characterized in that, In step (B), the selected specific gray level is the one that is considered optimal based on brightness analysis.

9. The method for one-stop brightness correction and local resistance potential drop compensation of an organic light-emitting diode panel as described in claim 1, characterized in that, In step (B), the brightness correction compensation value for the specific grayscale is stored in the flash memory.

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