TW202137188A - Brightness compensation method supporting different refresh rates of display panel - Google Patents

Abstract

A brightness compensation method supporting different refresh rates of a display panel is disclosed. The brightness compensation method includes steps of: (a) when a refresh rate of the display panel is a first refresh rate, using a first demura compensation data corresponding to the first refresh rate to compensate the display panel; (b) when the refresh rate of the display panel is changed from the first refresh rate to a second refresh rate, still using the first demura compensation data to compensate the display panel; and (c) using a specific brightness compensation technology to compensate the display panel.

Description

Support brightness compensation method of different update frequency of display panel

The present invention is related to display technology, and more particularly to a brightness compensation method that supports different refresh frequencies of a display panel.

Please refer to FIG. 1A to FIG. 1C and FIG. 2. Figures 1A to 1C respectively show several common dimming methods that can support different update frequencies of the display panel, such as extended vertical front porch (VFP), T1A, and skip frame (Skip frame) and other dimming methods. Schematic diagram; FIG. 2 is a schematic diagram showing the display panel PL receiving the gate clock signal GCLK from the gate driving circuit and the source clock signal SCLK from the gate driving circuit respectively.

As shown in Figure 1A and Figure 1C, when the extended vertical front-edge dimming method and the frame skipping dimming method are used for dimming of the display panel, the extended vertical front-edge dimming method and the frame skipping dimming method operate at a higher update frequency ( For example, 90Hz) and applications with a lower update frequency (e.g. 60Hz) will use the gate drive signal GOA corresponding to the higher update frequency (e.g. 90Hz), resulting in faster calculations at a lower update frequency (e.g. 60Hz) This causes the problem of a substantial increase in power consumption.

As shown in Figure 1B, when the T1A dimming method is used for dimming the display panel, the T1A dimming method will be used in applications with a higher update frequency (for example, 90 Hz) and a lower update frequency (for example, 60 Hz). The gate drive signal GOA has a higher update frequency (for example, 90 Hz) and a lower update frequency (for example, 60 Hz). At a lower update frequency (for example, 60 Hz), the timing of the gate clock signal GCLK and the source clock signal SCLK can be the same (as shown in FIG. 3A), so that the display panel PL can be charged and discharged normally and can maintain good brightness Uniformity (as shown in Figure 3B). However, at a higher update frequency (for example, 90 Hz), the timings of the gate clock signal GCLK and the source clock signal SCLK on both sides of the edge of the display panel PL are inconsistent (as shown in FIG. 4A), resulting in the display panel The two sides of the edge of the PL appear dark/color cast (for example, the edge is reddish) due to insufficient charge and discharge, which seriously affects the brightness uniformity of the display panel PL (as shown in FIG. 4B).

In order to solve this problem, the traditional method will first record the brightness uneven (Mura) distribution of the display panel in the application of a higher refresh frequency (for example, 90Hz) and a lower refresh frequency (for example, 60Hz), so as to achieve a higher refresh frequency. The corresponding Demura compensation data is used for applications with a lower update frequency, so that the display panel can maintain a good brightness uniformity under any update frequency application.

However, since the above-mentioned method needs to store uneven brightness compensation data at various update frequencies, the required memory capacity is greatly increased, which is in urgent need of improvement.

In view of this, the present invention proposes a brightness compensation method that supports different refresh frequencies of the display panel to effectively solve the above-mentioned problems encountered in the prior art.

A specific embodiment according to the present invention is a brightness compensation method that supports different refresh frequencies of a display panel. In this embodiment, the brightness compensation method includes the following steps: (a) When the refresh frequency of the display panel is the first refresh frequency, use the first brightness unevenness compensation data corresponding to the first refresh frequency to perform the display panel Compensation; (b) When the update frequency of the display panel changes from the first update frequency to the second update frequency, still use the first de-brightness compensation data to compensate the display panel; and (c) use a specific brightness compensation technology to compensate The display panel compensates.

In one embodiment, the display panel is an organic light emitting diode (OLED) display panel.

In one embodiment, the first update frequency is different from the second update frequency.

In one embodiment, the specific brightness compensation technology is Edge Bending Compensation (EBC) technology.

In one embodiment, the specific brightness compensation technology eliminates the color shift caused by insufficient charge and discharge in the at least one display area by changing the compensation data gain curve corresponding to the at least one display area of the display panel.

In one embodiment, changing the compensation data gain curve refers to increasing both sides of the compensation data gain curve on the horizontal axis.

In one embodiment, changing the compensation data gain curve refers to reducing both sides of the compensation data gain curve on the horizontal axis.

In one embodiment, changing the compensation data gain curve refers to increasing both sides of the compensation data gain curve on the vertical axis.

In one embodiment, changing the compensation data gain curve refers to reducing both sides of the compensation data gain curve on the vertical axis.

In one embodiment, changing the compensation data gain curve also supports individual settings for different colors.

In one embodiment, changing the compensation data gain curve also supports separate processing for different display areas.

In one embodiment, the waveform of the compensation data gain curve varies with the charging and discharging of the resistance and capacitance of the display panel.

In one embodiment, the brightness compensation method further includes: measuring the panel characteristics of the display panel at the first refresh frequency and calculating the first de-brightness unevenness compensation data; measuring the display panel at the second refresh frequency and According to the panel characteristics at other update frequencies, a plurality of compensation parameters corresponding to the second update frequency and other update frequencies are generated; a corresponding compensation data gain table is generated according to the current update frequency of the display panel; and according to the first de-brightness Both the compensation data and the compensation data gain table obtain the compensation data gain curve of the display panel at the current update frequency.

In one embodiment, the panel characteristics of the display panel include non-linearly changing brightness unevenness (Mura).

Compared with the prior art, the present invention proposes a brightness compensation method that supports different refresh frequencies of the display panel, which uses edge brightness compensation technology to solve the problem of poor brightness uniformity in the traditional T1A dimming method at higher refresh frequencies. And it will not increase the power consumption at a lower update frequency like the traditional extended vertical front dimming method and frame skipping dimming method, so that the display panel can maintain good brightness uniformity and power consumption regardless of the application of the update frequency. .

In addition, the brightness compensation method of the present invention does not need to increase the capacity of the memory, so it can effectively save cost and space, and regardless of whether the brightness unevenness (Mura) of the display panel changes linearly or non-linearly, the brightness compensation method of the present invention Both can be applied at the same time, so it can effectively improve the disadvantage that the prior art can only compensate for the uneven brightness of linear changes.

The advantages and spirit of the present invention can be further understood from the following detailed description of the invention and the accompanying drawings.

Reference will now be made in detail to the exemplary embodiments of the present invention, and examples of the exemplary embodiments are illustrated in the accompanying drawings. Elements/components with the same or similar numbers used in the drawings and embodiments are used to represent the same or similar parts.

A specific embodiment according to the present invention is a brightness compensation method that supports different refresh frequencies of a display panel. In this embodiment, the display panel may be an organic light-emitting diode (OLED) display panel, and the panel characteristics of the display panel may include linear or non-linear variation of brightness unevenness (Mura). The brightness compensation method of the present invention is both Applicable, but not limited to this.

Please refer to FIG. 5. FIG. 5 shows a flowchart of the brightness compensation method supporting different refresh frequencies of the display panel in this embodiment.

As shown in FIG. 5, the brightness compensation method in this embodiment may include the following steps:

Step S10: when the update frequency of the display panel is the first update frequency (for example, 60 Hz), use the first uneven brightness compensation data corresponding to the first update frequency to compensate the display panel;

Step S12: when the update frequency of the display panel is changed from the first update frequency to the second update frequency (for example, 90 Hz), still use the first de-brightness compensation data to compensate the display panel; and

Step S14: At the second update frequency, the display panel is compensated using a specific brightness compensation technique.

It should be noted that when the first update frequency is less than the second update frequency, that is, the brightness compensation method of the present invention uses the lower first update frequency and the higher second update frequency to correspond to the lower first update frequency. The first de-brightness unevenness compensation data of an update frequency compensates the display panel. Next, the brightness compensation method of the present invention further uses a specific brightness compensation technology to compensate at least one display area of the display panel at a higher second update frequency, so as to improve the brightness of the display panel at a higher second update frequency Evenness.

It is worth adding that the present invention can also use the second uneven brightness compensation data to be applied to the second update frequency to compensate for the display panel. In combination with the use of a specific brightness compensation technology, the brightness uniformity of the display panel at a lower first update frequency is improved.

Therefore, no matter how the refresh frequency of the display panel changes, the brightness compensation method of the present invention can correspondingly maintain a good brightness uniformity of the display panel without color shifting in some areas as in the prior art.

In practical applications, the specific brightness compensation technology can be an edge bending compensation (Edge Bending Compensation, EBC) technology, which can change at least one display area of the display panel (for example, at the left and right edges, but not limited to this). The corresponding compensation data gain curve is used to eliminate the color shift caused by insufficient charge and discharge in the at least one display area of the display panel (such as the left and right edges, but not limited to this) at a higher update frequency, but Not limited to this. It should be noted that the waveform of the gain curve of the compensation data is not fixed, but will vary with the charging and discharging of the resistance and capacitance of the display panel.

For example, as shown in FIG. 6A, when the update frequency of the display panel is 60 Hz, the brightness compensation method of the present invention uses Demura compensation data corresponding to 60 Hz to compensate the display panel (corresponding to step S10 in FIG. 5) . As shown in FIG. 6B, when the update frequency of the display panel is increased from 60 Hz to 90 Hz, the brightness compensation method of the present invention will still first use the Demura compensation data corresponding to 60 Hz to compensate the display panel (corresponding to step S12 in FIG. 5). ), and then use edge brightness compensation technology (such as EBC technology) to compensate at least one display area of the display panel (corresponding to step S14 in FIG. 5).

In practical applications, the brightness compensation method of the present invention can measure the panel characteristics of the display panel at the first update frequency (for example, the fundamental frequency 60Hz), and calculate the first uneven brightness compensation data based on the calculation, and measure the display panel The panel characteristics at the second update frequency (for example, 90 Hz) and other update frequencies are used to generate a plurality of compensation parameters corresponding to the second update frequency and other update frequencies. Next, the brightness compensation method of the present invention can also generate a corresponding compensation data gain table according to the current update frequency of the display panel (for example, 75 Hz), and obtain the current display panel according to the first brightness unevenness compensation data and the compensation data gain table. The compensation data gain curve at the update frequency (for example, 75 Hz) is used to compensate for the color shift phenomenon that occurs in at least one display area of the display panel.

Next, please refer to FIGS. 7A and 7B. FIG. 7A shows an example of a color shift phenomenon in a display panel, and FIG. 7B shows a schematic diagram of a compensation data gain curve used to compensate for the color shift phenomenon shown in FIG. 7A.

As shown in FIG. 7A, when the brightness of the left and right edges of the display panel PL is lower than the brightness of the central area, the brightness compensation method of the present invention will correspondingly increase the compensation on the horizontal axis (X axis) as shown in FIG. 7B The two sides of the data gain curve increase the brightness of the left and right edges of the display panel PL to maintain the brightness uniformity of the entire display panel PL.

Similarly, as shown in FIG. 8A, when the brightness of the left and right edges of the display panel PL is higher than the brightness of the central area, the brightness compensation method of the present invention will correspondingly lower the horizontal axis (X axis) as shown in FIG. 8B The two sides of the above compensation data gain curve reduce the brightness of the left and right sides of the display panel PL to maintain the brightness uniformity of the entire display panel PL.

In another embodiment, as shown in FIG. 9A, when the brightness of the upper and lower sides of the display panel PL is lower than the brightness of the central area, the brightness compensation method of the present invention will increase the vertical axis correspondingly as shown in FIG. 9B The two sides of the compensation data gain curve on the (Y axis) increase the brightness of the upper and lower edges of the display panel PL to maintain the brightness uniformity of the entire display panel PL.

In another embodiment, as shown in FIG. 10A, when the brightness of the upper and lower edges and the left and right edges of the display panel PL are lower than the brightness of the central area, the brightness compensation method of the present invention will be as shown in FIG. 7B and FIG. Figure 9B shows that both sides of the compensation data gain curve on the horizontal axis (X-axis) are increased and both sides of the compensation data gain curve on the vertical axis (Y-axis) are increased, so as to increase the left and right edges of the display panel PL and The brightness of the upper and lower edges is to maintain the brightness uniformity of the entire display panel PL.

In practical applications, the brightness compensation method of the present invention can also support processing for different display areas and individual settings for different colors, but it is not limited to this.

As shown in FIG. 10B, the display panel PL can include a first display area R1 and a second display area R2. When the brightness compensation method of the present invention changes the compensation data gain curve, it can also support different display areas (such as the first display area R1). And the second display area R2) are processed separately, but not limited to this.

As shown in FIG. 10C, each display area of the display panel PL can display different colors (for example, red R, green G, blue B). When the brightness compensation method of the present invention changes the compensation data gain curve, it can also support different colors. Set individually, but not limited to this.

Compared with the prior art, the present invention proposes a brightness compensation method that supports different refresh frequencies of the display panel, which uses edge brightness compensation technology to solve the problem of poor brightness uniformity in the traditional T1A dimming method at higher refresh frequencies. And it will not increase the power consumption at a lower update frequency like the traditional extended vertical front dimming method and frame skipping dimming method, so that the display panel can maintain good brightness uniformity and power consumption regardless of the application of the update frequency. .

In addition, the brightness compensation method of the present invention does not need to increase the capacity of the memory, so it can effectively save cost and space, and regardless of whether the brightness unevenness (Mura) of the display panel changes linearly or non-linearly, the brightness compensation method of the present invention Both can be applied at the same time, so it can effectively improve the disadvantage that the prior art can only compensate for the uneven brightness of linear changes.

GOA: Gate drive signal VSYN: vertical sync signal GCLK: gate clock signal SCLK: source clock signal PL: display panel CHA: Charging S10~S14: steps R1: the first display area R2: Second display area R: red G: green B: blue

The drawings of the present invention are described as follows: 1A to 1C show schematic diagrams of the traditional extended vertical front-end dimming method, T1A dimming method, and frame skipping dimming method, respectively. FIG. 2 is a schematic diagram showing the display panel respectively receiving the gate clock signal from the gate driving circuit and the source clock signal from the gate driving circuit. 3A and 3B show that when the traditional T1A dimming method is used, the source clock signal and the gate clock signal have the same timing at a lower update frequency (for example, 60 Hz), so that the display panel is charged and discharged normally to maintain Schematic diagram of good brightness uniformity. 4A and 4B show that when the traditional T1A dimming method is used, the timing of the source clock signal and the gate clock signal at a higher update frequency (for example, 90 Hz) is inconsistent, resulting in abnormal charging and discharging of the display panel. The timing chart of the color shift phenomenon on both sides of the edge. FIG. 5 shows a flowchart of a brightness compensation method supporting different refresh frequencies of a display panel according to a preferred embodiment of the present invention. FIG. 6A is a schematic diagram corresponding to step S10 in FIG. 5. FIG. 6B is a schematic diagram corresponding to steps S12 and S14 in FIG. 5. FIG. 7A illustrates an embodiment of the color shift phenomenon of the display panel. FIG. 7B is a schematic diagram of a compensation data gain curve used to compensate for the color shift phenomenon shown in FIG. 7A. FIG. 8A illustrates another embodiment of the color shift phenomenon of the display panel. FIG. 8B is a schematic diagram of a compensation data gain curve used to compensate for the color shift phenomenon shown in FIG. 8A. FIG. 9A illustrates another embodiment of the color shift phenomenon of the display panel. FIG. 9B is a schematic diagram of a compensation data gain curve used to compensate for the color shift phenomenon shown in FIG. 9A. 10A to 10C respectively illustrate other embodiments in which the color shift phenomenon occurs in the display panel.

S10~S14: steps

Claims (14)

A brightness compensation method supports different update frequencies of a display panel. The brightness compensation method includes the following steps: (a) When the update frequency of the display panel is a first update frequency, use a first de-brightness unevenness compensation data corresponding to the first update frequency to compensate the display panel; (b) when the display panel When the update frequency of is changed from the first update frequency to a second update frequency, still use the first de-brightness uneven compensation data to compensate the display panel; and (c) use a specific brightness compensation technology for the display panel Make compensation. The brightness compensation method according to claim 1, wherein the display panel is an organic light emitting diode (OLED) display panel. The brightness compensation method according to claim 1, wherein the first update frequency is different from the second update frequency. The brightness compensation method according to claim 1, wherein the specific brightness compensation technology is an edge bending compensation (Edge Bending Compensation, EBC) technology. The brightness compensation method according to claim 1, wherein the specific brightness compensation technology eliminates the at least one display area caused by insufficient charge and discharge by changing a compensation data gain curve corresponding to at least one display area of the display panel Color cast phenomenon. The brightness compensation method according to claim 5, wherein changing the compensation data gain curve includes: raising both sides of the compensation data gain curve on the horizontal axis. The brightness compensation method according to claim 5, wherein changing the compensation data gain curve includes: reducing both sides of the compensation data gain curve on the horizontal axis. The brightness compensation method according to claim 5, wherein changing the compensation data gain curve includes: raising both sides of the compensation data gain curve on the vertical axis. The brightness compensation method according to claim 5, wherein changing the compensation data gain curve includes: reducing both sides of the compensation data gain curve on the vertical axis. The brightness compensation method according to claim 5, wherein changing the compensation data gain curve includes: supporting separate settings for different colors. The brightness compensation method according to claim 5, wherein changing the compensation data gain curve includes: processing separately for different display areas. The brightness compensation method according to claim 5, wherein the waveform of the gain curve of the compensation data varies with the charging and discharging of a resistor and a capacitor of the display panel. The brightness compensation method according to claim 1, further comprising: measuring the panel characteristics of the display panel at the first update frequency and calculating the first compensation data for brightness unevenness; measuring the display panel According to the panel characteristics at the second update frequency and other update frequencies, a plurality of compensation parameters corresponding to the second update frequency and other update frequencies are generated, and the plurality of compensation parameters are stored in a memory; according to the display A current update frequency of the panel accesses the plurality of compensation parameters from the memory to generate a corresponding compensation data gain table; and obtains the display panel on the basis of the first de-brightness unevenness compensation data and the compensation data gain table A compensation data gain curve at the current update frequency. The brightness compensation method according to claim 1, wherein the panel characteristics of the display panel include non-linearly changing brightness unevenness (Mura).

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