1. A brightness compensation method for supporting different refresh frequencies of a display panel, the brightness compensation method comprising:

(a) when the update frequency of the display panel is a first update frequency, compensating the display panel by using first brightness unevenness compensation data corresponding to the first update frequency; (b) when the update frequency of the display panel is changed from the first update frequency to a second update frequency, the display panel is still compensated by the first brightness unevenness removal compensation data; and (c) compensating the display panel by using a specific brightness compensation technology.

2. The luminance compensation method as claimed in claim 1, wherein the display panel is an organic light emitting diode display panel.

3. The method of claim 1, wherein the first update frequency is different from the second update frequency.

4. The luminance compensation method of claim 1, wherein the specific luminance compensation technique is an edge warp compensation technique.

5. The method of claim 1, wherein the specific illumination compensation technique is to eliminate color shift of at least one display region of the display panel due to insufficient charging and discharging by changing a compensation data gain curve corresponding to the at least one display region.

6. The luminance compensation method of claim 5, wherein changing the compensation data gain curve comprises: the two sides of the compensated data gain curve on the horizontal axis are lifted.

7. The luminance compensation method of claim 5, wherein changing the compensation data gain curve comprises: the two sides of the compensated data gain curve on the horizontal axis are reduced.

8. The luminance compensation method of claim 5, wherein changing the compensation data gain curve comprises: the two sides of the compensated data gain curve on the vertical axis are lifted.

9. The luminance compensation method of claim 5, wherein changing the compensation data gain curve comprises: the two sides of the compensated data gain curve on the vertical axis are reduced.

10. The luminance compensation method of claim 5, wherein changing the compensation data gain curve comprises: support individual settings for different colors.

11. The luminance compensation method of claim 5, wherein changing the compensation data gain curve comprises: the processing is performed separately for different display areas.

12. The method of claim 5, wherein the waveform of the compensation data gain curve varies with different charging and discharging of a resistor and a capacitor of the display panel.

13. The luminance compensation method according to claim 1, further comprising: measuring the panel characteristics of the display panel at the first update frequency and calculating to obtain the first brightness unevenness compensation data; measuring the panel characteristics of the display panel at the second update frequency and other update frequencies to generate a plurality of compensation parameters corresponding to the second update frequency and other update frequencies, and storing the plurality of compensation parameters in a memory; accessing the plurality of compensation parameters from the memory according to a current update frequency of the display panel to generate a corresponding compensation data gain table; and obtaining a compensation data gain curve of the display panel at the current update frequency according to the first brightness unevenness compensation data and the compensation data gain table.

14. The luminance compensation method of claim 1, wherein the panel characteristic of the display panel comprises a non-linearly varying luminance nonuniformity.

Background

Please refer to fig. 1A to fig. 1C and fig. 2. Fig. 1A to 1C are schematic diagrams of several common dimming methods such as extended Vertical Front Port (VFP), T1A, and Skip frame (Skip frame) capable of supporting different update frequencies of a display panel, respectively; fig. 2 is a schematic diagram of 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 fig. 1A and 1C, when the extended vertical leading edge dimming method and the frame skipping dimming method are used to perform dimming on the display panel, the gate driving signal GOA corresponding to the higher update frequency (e.g., 90Hz) is used in both the higher update frequency (e.g., 90Hz) and the lower update frequency (e.g., 60Hz) in the extended vertical leading edge dimming method and the frame skipping dimming method, which results in a problem that the operation at the lower update frequency (e.g., 60Hz) needs to be accelerated, thereby greatly increasing the power consumption.

As shown in fig. 1B, when dimming the display panel by using the T1A dimming method, the T1A dimming method uses the gate driving signal GOA corresponding to the higher update frequency (e.g., 90Hz) and the lower update frequency (e.g., 60Hz) respectively under the application of the higher update frequency (e.g., 90Hz) and the lower update frequency (e.g., 60 Hz). At a lower refresh frequency (e.g. 60Hz), the timing of the gate clock signal GCLK and the source clock signal SCLK can be consistent (as shown in fig. 3A), so that the charging and discharging of the display panel PL are normal and good brightness uniformity can be maintained (as shown in fig. 3B). However, at a higher refresh frequency (e.g. 90Hz), the timing of the gate clock signal GCLK and the source clock signal SCLK corresponding to the two sides of the edge of the display panel PL are not consistent (as shown in fig. 4A), which causes the phenomenon of dark/color cast (e.g. red edge) on the two sides of the edge of the display panel PL due to insufficient charging/discharging, and seriously affects the brightness uniformity of the display panel PL (as shown in fig. 4B).

To solve this problem, the conventional method records the brightness non-uniformity (Mura) distribution of the display panel under the application of higher update frequency (e.g. 90Hz) and lower update frequency (e.g. 60Hz) so as to use the corresponding brightness non-uniformity (Demura) compensation data under the application of higher update frequency and lower update frequency, respectively, so that the display panel can maintain good brightness uniformity under any update frequency application.

However, since the above-mentioned method needs to store the de-luminance unevenness compensation data at various update frequencies, the required memory capacity is greatly increased, and improvement is needed.

Disclosure of Invention

Accordingly, the present invention is directed to a method for compensating brightness of a display panel with different update frequencies, so as to effectively solve the above-mentioned problems encountered in the prior art.

An embodiment of the present invention is a brightness compensation method for supporting different update frequencies of a display panel. In this embodiment, the brightness compensation method includes the following steps: (a) when the update frequency of the display panel is a first update frequency, compensating the display panel by using first brightness unevenness removal compensation data corresponding to the first update frequency; (b) when the update frequency of the display panel is changed from the first update frequency to the second update frequency, the display panel is still compensated by using the first brightness unevenness removal compensation data; and (c) compensating the display panel using a specific brightness compensation technique.

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 illumination Compensation technique is Edge warping Compensation (EBC).

In one embodiment, the specific brightness compensation technique eliminates color shift in at least one display region of the display panel due to insufficient charging and discharging by changing a compensation data gain curve corresponding to the at least one display region.

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

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

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

In one embodiment, changing the compensation data gain curve refers to decreasing the two 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 regions.

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

In one embodiment, the brightness compensation method further includes: measuring the panel characteristics of the display panel at a first updating frequency and calculating to obtain first brightness unevenness removal compensation data; measuring the panel characteristics of the display panel at the second update frequency and other update frequencies to generate a plurality of compensation parameters corresponding to the second update frequency and other update frequencies; generating a corresponding compensation data gain table according to the current updating frequency of the display panel; and obtaining a compensation data gain curve of the display panel under the current updating frequency according to the first brightness unevenness removal compensation data and the compensation data gain table.

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

Compared with the prior art, the present invention provides a luminance compensation method supporting different update frequencies of a display panel, which uses an edge luminance compensation technique to solve the problem of poor luminance uniformity at a higher update frequency in the conventional T1A dimming method, and does not increase power consumption at a lower update frequency as in the conventional extended vertical leading edge dimming method and the frame skipping dimming method, so that the display panel can maintain good luminance uniformity and power consumption no matter the display panel is applied at any update frequency.

In addition, the brightness compensation method of the invention does not need to additionally increase the capacity of the memory, so the cost and the space can be effectively saved, and the brightness compensation method of the invention can be simultaneously applied no matter the brightness unevenness (Mura) of the display panel is linear change or nonlinear change, so the defect that the prior art can only compensate the brightness unevenness of the linear change can be effectively improved.

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

Drawings

Fig. 1A to 1C are schematic diagrams of a conventional extended vertical front edge dimming method, a T1A dimming method, and a frame skipping dimming method, respectively.

Fig. 2 is a schematic diagram of the display panel respectively receiving a gate clock signal from the gate driving circuit and a source clock signal from the gate driving circuit.

Fig. 3A and 3B are schematic diagrams illustrating that when the conventional T1A dimming method is used, the timing of the source clock signal and the gate clock signal are consistent at a low refresh frequency (e.g., 60Hz) so that the charging and discharging of the display panel are normal to maintain good brightness uniformity.

Fig. 4A and 4B are timing diagrams illustrating a color shift phenomenon occurring at two side edges of a display panel due to abnormal charging and discharging of the display panel when a timing of a source clock signal and a timing of a gate clock signal are not consistent at a high refresh frequency (e.g., 90Hz) when a conventional T1A dimming method is used.

FIG. 5 is a flowchart illustrating a brightness compensation method supporting different update 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 is a schematic diagram illustrating an embodiment of a color shift phenomenon of a display panel.

FIG. 7B is a schematic diagram of a compensation data gain curve for compensating the color shift phenomenon shown in FIG. 7A.

FIG. 8A is a schematic diagram illustrating another embodiment of a color shift phenomenon of a display panel.

FIG. 8B is a schematic diagram of a compensation data gain curve for compensating the color shift phenomenon shown in FIG. 8A.

FIG. 9A is a schematic diagram illustrating an embodiment of a color shift phenomenon of a display panel.

FIG. 9B is a schematic diagram of a compensation data gain curve for compensating the color shift phenomenon shown in FIG. 9A.

Fig. 10A to 10C are other embodiments of the color shift phenomenon of the display panel, respectively.

Description of the main element symbols:

gate drive signals

Vertical synchronization signal

A gate clock signal

Source clock signal of SCLK

PL.

Charging of CHA

S10-S14

R1

R2

Red

Green

Blue color

Detailed Description

Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. The same or similar numbered elements/components used in the drawings and the embodiments are used to represent the same or similar parts.

An embodiment of the present invention is a brightness compensation method for supporting different update 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 linearly varying or non-linearly varying brightness unevenness (Mura).

Referring to fig. 5, fig. 5 is a flowchart illustrating a brightness compensation method supporting different update frequencies of a display panel according to this embodiment.

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

step S10: compensating the display panel by using first de-luminance unevenness compensation data corresponding to a first update frequency when the update frequency of the display panel is the first update frequency (for example, 60 Hz);

step S12: when the update frequency of the display panel is changed from the first update frequency to the second update frequency (for example, 90Hz), the display panel is still compensated by the first brightness unevenness removal compensation data; and

step S14: and compensating the display panel by using a specific brightness compensation technology at the second updating frequency.

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 utilizes the first de-mura compensation data corresponding to the lower first update frequency to compensate the display panel at both the lower first update frequency and the higher second update frequency. Then, the brightness compensation method of the invention further utilizes a specific brightness compensation technology to compensate at least one display area of the display panel under the higher second update frequency, so as to improve the brightness uniformity of the display panel under the higher second update frequency.

It is worth supplementing that the present invention can also use the second de-luminance unevenness compensation data to compensate the display panel with the second update frequency. And then, the brightness uniformity of the display panel under the lower first updating frequency is improved by matching and utilizing a specific brightness compensation technology.

Therefore, no matter how the update frequency of the display panel changes, the brightness compensation method of the invention can correspondingly maintain good brightness uniformity of the display panel without color cast phenomenon in partial area as in the prior art.

In practical applications, the specific brightness Compensation technique may be Edge warping Compensation (EBC), which can eliminate the color shift phenomenon caused by insufficient charging and discharging at a higher update frequency by changing a Compensation data gain curve corresponding to at least one display area (for example, but not limited to, left and right edges) of the display panel. It should be noted that the waveform of the compensation data gain curve is not constant, but varies with the charge and discharge of the resistor and capacitor of the display panel.

For example, as shown in fig. 6A, when the update frequency of the display panel is 60Hz, the brightness compensation method of the present invention compensates the display panel by using the Demura compensation data corresponding to 60Hz (corresponding to step S10 in fig. 5). As shown in fig. 6B, when the update frequency of the display panel is increased from 60Hz to 90Hz, the brightness compensation method of the present invention still compensates the display panel by using the Demura compensation data corresponding to 60Hz (corresponding to step S12 in fig. 5), and then compensates at least one display region of the display panel by using the edge brightness compensation technique (e.g., EBC technique) (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 a first update frequency (e.g., 60Hz at the base frequency) and calculate a first de-brightness unevenness compensation data accordingly, and measure the panel characteristics of the display panel at a second update frequency (e.g., 90Hz) and other update frequencies and generate a plurality of compensation parameters corresponding to the second update frequency and other update frequencies accordingly. Then, the brightness compensation method of the present invention may further generate a corresponding compensation data gain table according to the current update frequency (e.g. 75Hz) of the display panel, and obtain a compensation data gain curve of the display panel at the current update frequency (e.g. 75Hz) according to the first de-mura compensation data and the compensation data gain table, so as to compensate the color shift phenomenon occurring in at least one display region of the display panel.

Referring to fig. 7A and 7B, fig. 7A is a schematic diagram illustrating an embodiment of a color shift phenomenon occurring on a display panel, and fig. 7B is a schematic diagram illustrating a compensation data gain curve for compensating the color shift phenomenon illustrated 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 region, the brightness compensation method of the present invention correspondingly increases the two sides of the compensation data gain curve on the horizontal axis (X-axis) as shown in fig. 7B, so as to increase the brightness of the left and right edges of the display panel PL and 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 region, the brightness compensation method of the present invention correspondingly reduces the two sides of the compensation data gain curve on the horizontal axis (X axis) as shown in fig. 8B, so as to reduce the brightness of the left and right edges of the display panel PL and 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 edges of the display panel PL is lower than the brightness of the central region, the brightness compensation method of the present invention correspondingly increases the two sides of the compensation data gain curve on the vertical axis (Y-axis) as shown in fig. 9B, so as to increase the brightness of the upper and lower edges of the display panel PL and 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 correspondingly increases the two sides of the compensation data gain curve on the horizontal axis (X axis) and the two sides of the compensation data gain curve on the vertical axis (Y axis) at the same time as shown in fig. 7B and 9B, so as to increase the brightness of the left and right edges and the upper and lower edges of the display panel PL, thereby maintaining 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 regions and setting for different colors, but not limited thereto.

As shown in fig. 10B, the display panel PL may include a first display region R1 and a second display region R2, and may also support separate processing for different display regions (e.g., the first display region R1 and the second display region R2) when the brightness compensation method of the present invention changes the compensation data gain curve, but not limited thereto.

As shown in fig. 10C, each display region of the display panel PL can display different colors (e.g. red R, green G, and blue B), and the brightness compensation method of the present invention can also support setting for different colors when changing the compensation data gain curve, but not limited thereto.

Compared with the prior art, the present invention provides a luminance compensation method supporting different update frequencies of a display panel, which uses an edge luminance compensation technique to solve the problem of poor luminance uniformity at a higher update frequency in the conventional T1A dimming method, and does not increase power consumption at a lower update frequency as in the conventional extended vertical leading edge dimming method and the frame skipping dimming method, so that the display panel can maintain good luminance uniformity and power consumption no matter the display panel is applied at any update frequency.

In addition, the brightness compensation method of the invention does not need to additionally increase the capacity of the memory, so the cost and the space can be effectively saved, and the brightness compensation method of the invention can be simultaneously applied no matter the brightness unevenness (Mura) of the display panel is linear change or nonlinear change, so the defect that the prior art can only compensate the brightness unevenness of the linear change can be effectively improved.