TWI795118B - Initialization voltage dynamic adjustment method, OLED display device, and information processing device - Google Patents

Abstract

The present invention mainly discloses a method for dynamically adjusting initialization voltage, which includes the following steps: finding out a current frame initialization voltage from a lookup table based on the average display data calculated from the previous frame display data and the average display data of the current frame display data. Then, when performing reset and writing of display data of the current frame, the initialization voltage of the current frame is used as an initialization voltage of the pixel circuit unit. Finally, a reference initialization voltage is used as the initialization voltage of the pixel circuit unit when performing reset and writing of display data of the next frame. Therefore, even if there is a significant difference between the average display gray scale of the display data of the previous frame and the average display gray scale of the display data of the current frame, the method of the present invention can also reduce the adverse effect caused by the significant difference on the brightness of the display screen of the current frame ( brightness drop) to a minimum.

Description

Initialization voltage dynamic adjustment method, OLED display device, and information processing device

The invention relates to the technical field of display driving of an OLED display panel, in particular to a method for dynamically adjusting initialization voltage.

It is known that flat panel displays include non-self-illuminating flat-panel displays and self-illuminating flat-panel displays, wherein liquid crystal displays are a kind of non-self-illuminating flat-panel displays that have been used for a long time, and organic light-emitting diodes (Organic light-emitting diode, OLED) Displays and light-emitting diode (Light-emitting diode, LED) displays are conventional self-illuminating flat-panel displays. FIG. 1 shows a block diagram of a conventional OLED display. As shown in FIG. 1, the architecture of OLED display 1a mainly includes: an OLED display panel 11a, a gate (column) driving unit 12a, a source (row) driving unit 13a, a display controller 14a, and a voltage The conversion unit 15a, wherein the OLED display panel 11a includes M×N OLED sub-pixels 111a and M×N pixel circuit units 112a, where M and N are integers greater than 1. In more detail, the two electrical terminals of each OLED sub-pixel 111a are respectively coupled to a first driving voltage ELVDD and a second driving voltage ELVSS provided by the voltage converting unit 15a.

FIG. 2 is a front view of the OLED display panel shown in FIG. 1 . Practical experience shows that due to the hysteresis effect of the OLED display panel, when the previous frame is a black image, if the black image is switched to a white image in the current frame, the brightness of the white image will appear certain. degree of decline. For example, as shown in FIG. 2, the OLED display panel 11a is controlled so that the left half of the previous frame and the right half of the picture respectively display a black image (that is, gray 0) and a white image (that is, gray 0). , Gray 255). Next, the OLED display panel 11a is controlled so that both the left half frame and the right half frame of the current frame display a white image. It is worth noting that the brightness measurement value shows that the brightness of the white image displayed in the previous frame and the white image displayed in the current frame are both 250nits. However, after the black image displayed in the previous frame is switched to the white image in the current frame, the brightness of the white image is only 200 nits instead of 250 nits.

FIG. 3 is a circuit topology diagram of the pixel circuit unit 112a shown in FIG. 1 . As shown in FIG. 3, the pixel circuit unit 112a exemplary includes: a driving thin film transistor 1Da, a first thin film transistor 1M1a, a second thin film transistor 1M2a, a switching element 1Sa, and a storage capacitor 1Ca . Further, FIG. 4 is a working timing diagram of the gate voltage V _G shown in FIG. 3 , and FIG. 5 is a working timing diagram of the OLED current I _OLED shown in FIG. 3 . As shown in Figure 4, for a pixel circuit unit 112a that displays black pixels in the previous frame and white pixels in the current frame, the voltage between the gate voltage of the previous frame and the gate voltage of the current frame is There is a gate voltage difference (ie, ΔV _G1 ). After the reset and the writing of the display data of the current frame are completed in an initialization phase, it can be seen that the gate voltage difference still cannot be completely eliminated (ΔV _G2 still exists).

Comparing the waveform of the OLED current I _OLED shown in FIG. 5 , it can be found that the gate voltage difference (ΔV _G2 ) causes the current frame OLED current of the OLED sub-pixel 111a driven by the pixel circuit unit 112a to be equal to the OLED current of the current frame. A certain degree of current difference also occurs between the currents. Therefore, as shown in FIG. 2 , after the black image displayed in the previous frame is switched to the white image in the current frame, the brightness of the white image is only 200 nits instead of 250 nits. Special attention must be paid to the fact that with the improvement of the display frame, the reset time and display data writing time are forced to be shortened, and this will cause the second gate voltage difference ΔV _G2 to become larger, so that when the black image is switched to the white image , the brightness of the white image will drop more.

It can be seen from the above description that there is an urgent need in the art for a method for dynamically adjusting the initialization voltage.

The main purpose of the present invention is to provide a dynamic adjustment method for initialization voltage, which is used to dynamically adjust the pixel when there is a significant difference between the average display gray scale of the previous frame display data and the average display gray scale of the current frame display data. The initialization voltage of the circuit unit is used to minimize the adverse effect (decrease in brightness) caused by the significant difference on the brightness of the current frame display image.

In order to achieve the above purpose, the present invention proposes an embodiment of the method for dynamically adjusting the initialization voltage, which is used to dynamically initialize the voltage of an OLED display panel including M×N OLED sub-pixels and M×N pixel circuit units. For adjustment, M and N are integers greater than 1, and include the following steps:

calculating a first average display data according to the previous frame display data, and calculating a second average display data according to the current frame display data;

Finding a current frame initialization voltage from a lookup table according to the first average display data and the second average display data;

When performing reset and writing the display data of the current frame, using the initialization voltage of the current frame as an initialization voltage of the pixel circuit unit; and

A reference initialization voltage is used as the initialization voltage of the pixel circuit unit when performing reset and writing of display data of the next frame.

In one embodiment, the lookup table is a three-dimensional lookup table including a previous frame display data axis, a current frame display data axis, and an initialization voltage axis, and the previous frame display data axis and the current frame display data axis There are K gamma binding points for the axis, and K is a positive integer greater than 1.

In an embodiment, the grayscale value of the first gamma binding point and the grayscale value of the Kth gamma binding point of the display data axis of the current frame and the display data axis of the previous frame are both 0 and 0 respectively. 255.

In an embodiment, along the current frame display data axis, each of the gamma binding points has a corresponding initialization voltage of the current frame, and corresponds to the jth of the jth gamma binding point The absolute value of the current frame initialization voltage is greater than the absolute value of the j-1th current frame initialization voltage corresponding to the j-1th gamma binding point, and j is a positive integer greater than 1.

In one embodiment, when the second average display data falls between the jth gamma binding point and the j-1th gamma binding point, the interpolation method is used to calculate The current frame initialization voltage corresponding to the second average display data.

Moreover, the present invention also provides an OLED display device, which includes at least one display driver chip and an OLED display panel, wherein the display driver chip has an initialization voltage adjustment unit for performing a method for dynamically adjusting the initialization voltage; the initialization voltage The dynamic adjustment method includes the following steps:

calculating a first average display data according to the previous frame display data, and calculating a second average display data according to the current frame display data;

Finding a current frame initialization voltage from a lookup table according to the first average display data and the second average display data;

When performing reset and writing the display data of the current frame, using the initialization voltage of the current frame as an initialization voltage of the pixel circuit unit; and

A reference initialization voltage is used as the initialization voltage of the pixel circuit unit when performing reset and writing of display data of the next frame.

In one embodiment, the lookup table is a three-dimensional lookup table including a previous frame display data axis, a current frame display data axis, and an initialization voltage axis, and the previous frame display data axis and the current frame display data axis There are K gamma binding points for the axis, and K is a positive integer greater than 1.

In an embodiment, the grayscale value of the first gamma binding point and the grayscale value of the Kth gamma binding point of the display data axis of the current frame and the display data axis of the previous frame are both 0 and 0 respectively. 255.

In an embodiment, along the current frame display data axis, each of the gamma binding points has a corresponding initialization voltage of the current frame, and corresponds to the jth of the jth gamma binding point The absolute value of the current frame initialization voltage is greater than the absolute value of the j-1th current frame initialization voltage corresponding to the j-1th gamma binding point, and j is a positive integer greater than 1.

In one embodiment, when the second average display data falls between the jth gamma binding point and the j-1th gamma binding point, the interpolation method is used to calculate The current frame initialization voltage corresponding to the second average display data.

The present invention also provides an information processing device, which has the aforementioned OLED display device of the present invention.

In one embodiment, the information processing device is selected from the group consisting of smart phones, smart watches, smart bracelets, tablet computers, notebook computers, all-in-one computers, access control devices, and electronic door locks an electronic device.

In order to enable your examiners to further understand the structure, features, purpose, and advantages of the present invention, drawings and detailed descriptions of preferred embodiments are hereby attached.

Please refer to FIG. 6 , which shows a block diagram of an OLED display device applying a method for dynamically adjusting initialization voltage of the present invention. As shown in FIG. 6, the OLED display device includes an OLED display panel 11 and at least one display driver chip 12, wherein the OLED display panel 11 includes M×N OLED sub-pixels 111 and M×N pixel circuit units 112 , M and N are both integers greater than 1. It should be noted that, in the case of applying a method for dynamically adjusting the initialization voltage of the present invention, the display driver chip 12 has a look-up table 121 and an initialization voltage adjustment unit 122 . In more detail, the lookup table 121 is a three-dimensional lookup table including a previous frame display data axis, a current frame display data axis and an initialization voltage axis.

FIG. 7 is an example diagram of a three-dimensional coordinate axis of the lookup table 121 shown in FIG. 6 , and FIG. 8 is an example table diagram of the lookup table 121 shown in FIG. 6 . As shown in Figure 6 and Figure 7, the previous frame (i.e., j-1th frame) display data axis and the current frame (i.e., jth frame) display data axis are provided with K gamma binding points, K is A positive integer greater than 1. For example, there are 8 gamma binding points, namely Gray 0, Gray 32, Gray 64, Gray 128, Gray 160, Gray 192, Gray 224, and Gray 255. In other words, the grayscale value of the first gamma binding point and the grayscale value of the Kth gamma binding point of the display data axis of the current frame and the display data axis of the previous frame are 0 and 255, respectively.

Further, FIG. 9 shows a flow chart of a method for dynamically adjusting the initialization voltage of the present invention. In the case where the initialization voltage dynamic adjustment method of the present invention is applied, the display driver chip 12 will provide the pixel circuit unit 112 with its initialization voltage adjustment unit 122 during the display driving process of the OLED display panel 11. An initialization voltage Vint of 1 is dynamically adjusted. First, the initialization voltage adjustment unit 122 performs step S1: calculate a first average display data according to the display data of the previous frame (ie, frame j-1), and calculate a first average display data based on the display data of the current frame (ie, frame j) Output a second average display data, j is an integer greater than 1. Next, step S2 is executed: searching a current frame initialization voltage from a lookup table 121 according to the first average display data and the second average display data. For example, the first average display data is Gray 0 (that is, displaying a black image) and the second average display data is Gray 64. At this time, it can be found from the lookup table 121 that the initialization voltage of the current frame is V _{INT_1} .

For another example, if the first average display data is Gray 32 and the second average display data is Gray 160, then the initialization voltage of the current frame can be found out from the lookup table 121 as V _{INT — 9} . In other words, along the display data axis of the current frame (that is, the jth frame), each of the gamma binding points has a corresponding initialization voltage (V _{INT_J} ) of the current frame, and corresponds to the jth frame The absolute value of the initialization voltage of the jth current frame of the gamma binding point is greater than the absolute value of the initialization voltage of the j-1th current frame corresponding to the j-1th gamma binding point, j is a positive integer. Of course, in most cases, the second average display data will not be exactly equal to the preset gamma binding point. Therefore, according to the design of the present invention, when the second average display data falls between the jth gamma binding point and the j-1th gamma binding point, an interpolation method can be used calculating the current frame initialization voltage corresponding to the second average display data.

Continuing, the method flow is to execute step S3: when executing reset and writing of display data of the current frame, using the initialization voltage of the current frame as an initialization voltage of the pixel circuit unit. Please refer to FIG. 3 and FIG. 4 repeatedly, there is an initialization stage between the display stage of the previous frame and the display stage of the current frame. In the initialization stage, the pixel circuit unit 112 will reset and write the display data of the current frame. Therefore, according to the design of the present invention, in step S3, when performing reset and writing of display data of the current frame, the current frame initialization voltage V _{INT_J} obtained from the lookup table 121 is used as the pixel circuit unit 112 an initialization voltage Vint.

Finally, the method flow is to execute step S4: when performing reset and writing of display data of the next frame (ie, j+1th frame), a reference initialization voltage (ie, V _REF shown in FIG. 8 ) is used as the The initialization voltage of the pixel circuit unit. It can be seen from the foregoing description that the absolute value of each current frame initialization voltage V _{INT_J} is greater than the absolute value of a reference initialization voltage V _REF preset by the circuit.

FIG. 10 is a working timing diagram of the OLED current shown in FIG. 6 . For a pixel circuit unit 112 that displayed black pixels in the previous frame (that is, the j-1th frame) and displayed white pixels in the current frame (that is, the jth frame), its previous frame gate There must be a gate voltage difference between the electrode voltage and the gate voltage of the current frame, and this gate voltage difference causes the OLED current of the previous frame and the current frame OLED current of the OLED sub-pixel 111 driven by the pixel circuit unit 112 A certain degree of current difference also occurs between the currents. As shown in Figure 10, in the case of applying the initialization voltage dynamic adjustment method of the present invention, the value of the current frame initialization voltage V _{INT_J} is dynamically adjusted from -3.1V to -5.0V, so that the current difference is greatly reduced (8% →3%).

In this way, the above has completely and clearly described a method for dynamically adjusting the initialization voltage of the present invention; and, through the above, it can be known that the present invention has the following advantages:

(1) The present invention discloses a method for dynamically adjusting the initialization voltage, which is used to dynamically adjust the pixel circuit when there is a significant difference between the average display gray scale of the previous frame display data and the average display gray scale of the current frame display data The initialization voltage of the unit, in this way, the adverse effect (brightness drop) caused by this significant difference on the brightness of the current frame display screen is minimized.

(2) The present invention also provides an OLED display device, which includes at least one display driver chip and an OLED display panel, and the display driver chip has a look-up table and an initialization voltage adjustment unit, so as to be able to perform the aforementioned initialization of the present invention Voltage dynamic adjustment method.

(3) The present invention also provides an information processing device having the aforementioned OLED display device of the present invention. Moreover, the information processing device is an electronic device selected from the group consisting of smart phones, smart watches, smart bracelets, tablet computers, notebook computers, all-in-one computers, access control devices, and electronic door locks .

It must be emphasized that what is disclosed in the above-mentioned case is a preferred embodiment, and all partial changes or modifications derived from the technical ideas of this case and easily deduced by those familiar with the technology are all inseparable from the patent of this case. category of rights.

To sum up, the purpose, means and efficacy of this case all show that it is very different from the conventional technology, and its first invention is practical, and indeed meets the patent requirements of the invention. I implore your review committee to be aware and grant a patent as soon as possible to benefit you. Society is for the Most Prayer.

1a: OLED display 11a: OLED display panel 111a: OLED sub-pixel 112a: pixel circuit unit 12a: Gate drive unit 13a: Source drive unit 14a: Display Controller 15a: Voltage conversion unit 1: OLED display device 11:OLED display panel 111: OLED sub-pixel 112:Pixel circuit unit 12: Display driver chip 121:Lookup table 122: Initialize the voltage adjustment unit S1: Calculate a first average display data based on the previous frame display data, and calculate a second average display data based on the current frame display data S2: Find a current frame initialization voltage from a lookup table according to the first average display data and the second average display data S3: When performing reset and writing of the display data of the current frame, using the initialization voltage of the current frame as an initialization voltage of the pixel circuit unit S4: When performing reset and writing of the display data of the next frame, use a reference initialization voltage as the initialization voltage of the pixel circuit unit

FIG. 1 is a block diagram of a known OLED display; FIG. 2 is a front view of the OLED display panel shown in FIG. 1; FIG. 3 is a circuit topology diagram of the pixel circuit unit shown in FIG. 1; FIG. 4 is a working timing diagram of the gate voltage shown in FIG. 3; FIG. 5 is a working timing diagram of the OLED current shown in FIG. 3; FIG. 6 is a block diagram showing an OLED display device applied with a method for dynamically adjusting an initialization voltage of the present invention; Fig. 7 is an exemplary diagram of a three-dimensional coordinate axis of the look-up table shown in Fig. 6; Fig. 8 is an exemplary table diagram of the look-up table shown in Fig. 6; Fig. 9 is a flowchart of a method for dynamically adjusting initialization voltage of the present invention; and FIG. 10 is a working timing diagram of the OLED current shown in FIG. 6 .

S1: Calculate a first average display data based on the previous frame display data, and calculate a second average display data based on the current frame display data

S2: Find a current frame initialization voltage from a lookup table according to the first average display data and the second average display data

S3: When performing reset and writing of the display data of the current frame, using the initialization voltage of the current frame as an initialization voltage of the pixel circuit unit

S4: When performing reset and writing of the display data of the next frame, use a reference initialization voltage as the initialization voltage of the pixel circuit unit

Claims (6)

A method for dynamically adjusting the initialization voltage, which is used for dynamically adjusting the initialization voltage of an OLED display panel including M×N OLED sub-pixels and M×N pixel circuit units, where M and N are both integers greater than 1, and The method comprises the following steps: calculating a first average display data according to the previous frame display data, and calculating a second average display data according to the current frame display data; A current frame initialization voltage is found in the lookup table; when performing reset and writing of display data of the current frame, using the current frame initialization voltage as an initialization voltage of the pixel circuit unit; and performing reset and the next When writing frame display data, a reference initialization voltage is used as the initialization voltage of the pixel circuit unit; wherein, the lookup table includes a previous frame display data axis, a current frame display data axis, and an initialization voltage A three-dimensional lookup table for the axis, and the previous frame display data axis and the current frame display data axis are provided with K gamma binding points, K is a positive integer greater than 1; along the current frame display data axis, each The gamma binding point has a current frame initialization voltage corresponding to it, and the absolute value of the jth current frame initialization voltage corresponding to the jth gamma binding point is greater than that corresponding to the j-1th gamma binding point The absolute value of the initialization voltage of the j-1th current frame of the gamma binding point, where j is a positive integer greater than 1. The initialization voltage dynamic adjustment method according to claim 1, wherein the current frame displays the data axis and the previous frame displays the gray scale value of the first gamma binding point and the Kth gamma binding point of the data axis The gray scale values of are 0 and 255 respectively. The initialization voltage dynamic adjustment method according to claim 1, wherein, when the second average display data falls between the jth gamma binding point and the j-1th gamma binding point Next, the current frame initialization voltage corresponding to the second average display data is calculated by using an interpolation method. An OLED display device comprising at least one display driver chip and an OLED display panel, wherein the display driver chip has an initialization voltage adjustment unit for performing a dynamic initialization voltage adjustment method; the initialization voltage dynamic adjustment method includes the following steps : Calculate a first average display data according to the previous frame display data, and calculate a second average display data according to the current frame display data; find out a current frame initialization voltage; when performing reset and writing the display data of the current frame, use the current frame initialization voltage as an initialization voltage of a plurality of pixel circuit units; and when performing reset and displaying the next frame When writing data, a reference initialization voltage is used as the initialization voltage of the pixel circuit unit; wherein, the look-up table includes a previous frame display data axis, a current frame display data axis and an initialization voltage axis A three-dimensional lookup table, and the previous frame display data axis and the current frame display data axis are provided with K gamma binding points, K is a positive integer greater than 1; along the current frame display data axis, each of the The gamma binding point has a current frame initialization voltage corresponding to it, and the absolute value of the jth current frame initialization voltage corresponding to the jth gamma binding point is greater than that corresponding to the j-1th The absolute value of the initialization voltage of the j-1th current frame of the gamma binding point, where j is a positive integer greater than 1. The OLED display device according to claim 4, wherein, when the second average display data falls between the jth gamma binding point and the j-1th gamma binding point, The current frame initialization voltage corresponding to the second average display data is calculated by using an interpolation method. An information processing device having the OLED display device described in any one of Claim 4 to Claim 5.

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