Data line voltage determining method, determining device and driving method
阅读说明：本技术 一种数据线电压确定方法、确定装置及驱动方法 (Data line voltage determining method, determining device and driving method ) 是由 戴文彬 于 2020-06-29 设计创作，主要内容包括：本申请提供一种数据线电压确定方法、确定装置及驱动方法,所述数据线电压确定方法包括：将显示装置的显示面板划分为n个区块,n为大于2的正整数,n个区块具有相同的参考电压最大值和最小值,以及相同的伽马寄存器值；将第n个区块的参考电压的范围划分为Dn等份,其中,Dn的取值与第n个区块内像素电极到驱动芯片连接的电源线长度的电源线阻抗呈负相关相关关系；根据参考电压的最大值、最小值、伽马寄存器值以及Dn,确定第n个区块内像素电极的数据线电压。通过调整每个区块内参考电压范围的划分等份值调整数据线电压,从而使得区块对应的显示亮度与目标亮度相同,进而达到提高显示面板整体显示均一性的目的。(The application provides a data line voltage determining method, a determining device and a driving method, wherein the data line voltage determining method comprises the following steps: dividing a display panel of the display device into n blocks, wherein n is a positive integer greater than 2, and the n blocks have the same maximum value and the same minimum value of a reference voltage and the same gamma register value; dividing the range of the reference voltage of the nth block into equal parts Dn, wherein the value of Dn and the power line impedance of the length of the power line connecting the pixel electrode in the nth block to the driving chip are in a negative correlation relationship; and determining the data line voltage of the pixel electrode in the nth block according to the maximum value and the minimum value of the reference voltage, the gamma register value and Dn. The data line voltage is adjusted by adjusting the divided equal parts of the reference voltage range in each block, so that the display brightness corresponding to the block is the same as the target brightness, and the aim of improving the overall display uniformity of the display panel is fulfilled.)
1. A data line voltage determining method is applied to a driving chip of a display device, and comprises the following steps:
dividing a display panel of the display device into n blocks, wherein n is a positive integer greater than 2, and the n blocks have the same maximum value and minimum value of a reference voltage and the same gamma register value;
dividing the range of the reference voltage of the nth block into equal parts Dn, wherein the value of Dn is in a correlation relation with the impedance of a power line from a pixel electrode in the nth block to the driving chip;
and determining the data line voltage of the pixel electrode in the nth block according to the maximum value and the minimum value of the reference voltage, the gamma register value and the Dn.
2. The method of claim 1, wherein the value of Dn is inversely related to the power line impedance from the pixel electrode to the driver chip in the nth block.
3. The method of claim 2, wherein when the range of the reference voltage of the nth block is divided into equal portions Dn, the method of determining Dn specifically comprises:
dividing the range of the reference voltage of each block into equal initial values;
detecting the display brightness of each block;
determining target brightness;
and adjusting the range division equal part value of the reference voltage of each block, so that the difference between the display brightness of each block and the target brightness is within a preset range.
4. The method for determining the data line voltage according to claim 3, wherein the determining the target brightness specifically comprises:
and taking the display brightness of the central block of the display panel as the target brightness.
5. The method for determining the voltage of the data line according to claim 4, wherein the adjusting the range of the reference voltage of each block into equal parts to make the difference between the display brightness of each block and the target brightness within a preset range comprises:
sequentially numbering all blocks in the display panel according to the descending order of the power line impedance from the pixel electrodes in the blocks to the driving chip, wherein the numbers of the blocks are 1, 2 and … … n;
dividing the range of the reference voltage of the 1 st block into m Δ D equal parts increased by the initial value, dividing the range of the reference voltage of the 2 nd block into m-1 Δ D equal parts increased by the initial value, and recurrently dividing the range of the reference voltage of the k-th block into m- Δ D equal parts increased by the initial value and (m-k-1) Δ D equal parts … …, and dividing the range of the reference voltage of the nth block into m- Δ D equal parts increased by the initial value, wherein when n is an even number, m is n/2, and when n is an odd number, m is (n-1)/2;
detecting the display brightness of each block;
comparing the target brightness, and if the difference between the display brightness of the ith block and the target brightness is within a preset range, determining the range division equal part value of the current reference voltage of the ith block as Di;
and if the difference between the display brightness of the jth block and the target brightness is out of the preset range, continuously adjusting the range of the reference voltage of the jth block to divide equal parts until the difference between the display brightness of the jth block and the target brightness is in the preset range, wherein j is not equal to i.
6. The method for determining the voltage of the data line according to claim 5, wherein if the difference between the display brightness of the jth block and the target brightness is outside a preset range, the step of continuously adjusting the range of the reference voltage of the jth block to divide the voltage into equal parts comprises:
and adjusting the size of delta D in the range division equal parts of the reference voltage of the jth block according to the approaching trend of the display brightness of the jth block and the target brightness.
7. The method for determining the voltage of the data line according to claim 5, wherein if the difference between the display brightness of the jth block and the target brightness is outside a preset range, the step of continuously adjusting the range of the reference voltage of the jth block to divide the voltage into equal parts comprises:
and adjusting the number of delta D in the range division equal parts of the reference voltage of the jth block according to the approaching trend of the display brightness of the jth block and the target brightness.
8. The method of claim 1, wherein the determining the data line voltages of the pixel electrodes in the nth block according to the maximum value, the minimum value, the gamma register value and the Dn comprises:
Vdata_n＝Vgmp-(Vgmp-Vgsp)*d/Dn
wherein Vdata _ n represents a data line voltage of a pixel electrode in the nth block; vgmp is the maximum value of the reference voltage; vgsp is the reference voltage minimum; d is a gamma register value corresponding to the current gray scale of the pixel unit where the pixel electrode is located; dn is the number of divided parts of the range of the reference voltage of the nth block.
9. The method for determining the voltage of the data line according to claim 1, wherein the dividing the display panel of the display device into n blocks specifically comprises:
and dividing the display panel into n equal parts along the direction of the connecting line of the central point of the display panel and the central point of the driving chip.
10. The method for determining the voltage of the data line according to claim 1, wherein the dividing the display panel of the display device into n blocks specifically comprises:
and dividing the display panel into n blocks according to the number of the pixel units, wherein each block corresponds to at least one pixel unit.
11. The method for determining the voltage of the data line according to claim 1, wherein the dividing the display panel of the display device into n blocks specifically comprises:
and dividing the display panel into n blocks according to the number of the pixel electrodes, wherein each block corresponds to at least one pixel.
12. The method of claim 1, wherein a value of Dn is positively correlated to a power line impedance from the pixel electrode to the driver chip in the nth block.
13. A data line voltage determining apparatus in a driving chip of a display apparatus, the data line voltage determining apparatus comprising:
the display device comprises a dividing module, a storage module and a control module, wherein the dividing module is used for dividing a display panel of the display device into n blocks, n is a positive integer greater than 2, and the n blocks have the same maximum value and the same minimum value of a reference voltage and the same gamma register value;
the reference voltage dividing module is used for dividing the range of the reference voltage of the nth block into equal parts Dn, wherein the value of Dn is in a correlation relation with the impedance of a power line from the pixel electrode in the nth block to the driving chip;
and the data line voltage calculation module is used for determining and obtaining the data line voltage of the pixel electrode in the nth block according to the maximum value and the minimum value of the reference voltage, the gamma register value and the Dn.
14. A driving method applied to a display device, the driving method comprising:
determining a block where the pixel electrode is located;
outputting the data line voltage corresponding to the pixel electrode according to the preset relation between the block and the data line voltage, and driving the pixel electrode to display;
wherein the data line voltage is determined using the data line voltage determination method of any one of claims 1-12.
Technical Field
The invention relates to the technical field of display, in particular to a data line voltage determining method, a determining device and a driving method.
Background
From the CRT (Cathode Ray Tube) era to the liquid crystal era and now to the OLED (Organic Light-Emitting Diode) era, the display industry has been developing over decades. The display industry is closely related to our lives, and display technologies cannot be separated from traditional mobile phones, flat panels, televisions and PCs, to current intelligent wearable devices and VRs.
In general, a display panel is provided with a power supply signal line electrically connected to each pixel, and the power supply signal line is also connected to a driver chip which supplies a power supply voltage to each pixel through the power supply signal line as a power supply voltage required for each pixel to emit light.
However, due to the different impedances of the power signal lines, the brightness of different areas on the display panel is different, and the display uniformity is poor.
Disclosure of Invention
In view of the above, the present invention provides a method, a device and a method for determining a data line voltage, so as to solve the problem of poor display uniformity caused by different impedances of power signal lines in the prior art.
In order to achieve the purpose, the invention provides the following technical scheme:
a data line voltage determining method is applied to a driving chip of a display device and comprises the following steps:
dividing a display panel of the display device into n blocks, wherein n is a positive integer greater than 2, and the n blocks have the same maximum value and minimum value of a reference voltage and the same gamma register value;
dividing the range of the reference voltage of the nth block into equal parts Dn, wherein the value of Dn is in a correlation relation with the impedance of a power line from a pixel electrode in the nth block to the driving chip;
and determining the data line voltage of the pixel electrode in the nth block according to the maximum value and the minimum value of the reference voltage, the gamma register value and the Dn.
The present invention also provides a data line voltage determining device in a driving chip of a display device, the data line voltage determining device including:
the display device comprises a dividing module, a storage module and a control module, wherein the dividing module is used for dividing a display panel of the display device into n blocks, n is a positive integer greater than 2, and the n blocks have the same maximum value and the same minimum value of a reference voltage and the same gamma register value;
the reference voltage dividing module is used for dividing the range of the reference voltage of the nth block into equal parts Dn, wherein the value of Dn is in a correlation relation with the impedance of a power line from the pixel electrode in the nth block to the driving chip;
and the data line voltage calculation module is used for determining and obtaining the data line voltage of the pixel electrode in the nth block according to the maximum value and the minimum value of the reference voltage, the gamma register value and the Dn.
In addition, the present invention also provides a driving method applied to a display device, the driving method including:
determining a block where the pixel electrode is located;
outputting the data line voltage corresponding to the pixel electrode according to the preset relation between the block and the data line voltage, and driving the pixel electrode to display;
wherein the data line voltage is determined using the data line voltage determination method described above.
According to the technical scheme, the data line voltage determining method provided by the invention is applied to the driving chip of the display device, namely the data line voltage determining method output by the driving chip, the determining method divides the display panel into a plurality of blocks on the basis of algorithm, the reference voltage range of each block is the same, the reference voltage range has the same maximum value and the same minimum value of the reference voltage, and each block also has the same gamma register value; the difference is that the divided equal parts of the range of the reference voltage in each block are different, and the divided equal parts are in a correlation relation with the power line impedance from the pixel electrode in the block to the driving chip. That is, the reference voltage range of each block is divided into different equal parts according to different resistances of power lines from the pixel electrodes to the driving chip in the block, so that different data line voltages are obtained by changing the divided equal parts of the reference voltage range to be different under the condition that each block has the same gamma register value and the same reference voltage range, and the data line voltages can compensate the IR voltage drop caused by the resistances of the power lines, thereby improving the uniformity of the display brightness of the display panel.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic diagram of a PVEE signal line structure provided in the prior art;
FIG. 2 is a schematic diagram of a PVDD signal line structure provided in the prior art;
FIG. 3 is a flow chart of a method for determining a data line voltage according to an embodiment of the present invention;
FIG. 4 is a block diagram of a display panel with double-side driving according to an embodiment of the present invention;
FIG. 5 is a block diagram of a display panel according to another double-side driving scheme in an embodiment of the present invention;
fig. 6 is a schematic diagram of a display panel adopting a double-side driving method for block division in the present embodiment;
FIG. 7 is a flow chart of a method of determining the range-divided-equal-fraction values of the reference voltage for each block;
FIG. 8 is a schematic diagram of a data line voltage determining apparatus according to an embodiment of the present invention;
fig. 9 is a flowchart of a driving method according to an embodiment of the present invention.
Detailed Description
As described in the background section, the luminance of different areas on the display panel is different in the related art due to the difference in the impedance of the power signal lines.
The inventors found that the power supply signal line generally includes a PVEE signal line and a PVDD signal line, where PVDD refers to Pixel VDD and PVEE refers to Pixel VEE, where Pixel represents a Pixel, VDD represents a positive voltage, and VEE represents a negative voltage. Thus, PVDD represents a positive voltage to the pixel and PVEE represents a negative voltage to the pixel.
As shown in fig. 1, a schematic diagram of a PVEE signal line structure provided in the prior art is shown; in the prior art, the PVEE signal line is of a strip or whole-surface structure, and the whole-surface structure is opposite to the strip structure, so that the negative voltage of the pixel is basically uniform; as shown in fig. 2, a schematic diagram of a PVDD signal line structure provided in the prior art is shown, because the PVDD signal line provides a driving voltage for a pixel electrode in each pixel, the PVDD signal line has a stripe structure.
In order to improve the resolution of the display panel, the size of the display panel is increasing, and in order to realize a larger display area, a narrow frame becomes a mainstream for development, however, in terms of the current technology, the driving chip can only be arranged in the frame area, generally in the lower frame position of the display panel, which makes it impossible to arrange an equal-resistance power signal line between the data line connected to each pixel electrode and the driving chip, and generally, the power signal line between the data line near the driving chip and the driving chip is shorter and has smaller resistance; and the power signal line between the data line far away from the lower frame and the driving chip is longer and the resistance is larger, so that the voltage drop of the area far away from the driving chip and the voltage drop of the area near the driving chip are different, namely, the brightness of the display area of the whole display panel near the driving chip is higher than that of the display area far away from the driving chip, so that the display panel has the problem of uneven brightness display.
Therefore, the impedance of the pixel electrode to the power supply line of the driving chip is related to the luminance of the display panel, but on the one hand, if the PVEE signal line has a full-surface structure, the resistance is relatively small; the PVDD signal line resistance of the strip structure is relatively large; on the other hand, during the display process of the display panel, the switching transistor (TFT) of the pixel usually operates in the saturation region, and the brightness is not related to the voltage on the PVEE line, so the brightness of the display panel is only related to the voltage on the PVDD signal line, and the relationship between the brightness LV and the PVDD voltage can be expressed as LV- (V) — (V)data-VPVDD)2. Therefore, the PVDD voltage drops at different positions are different, and the display brightness can be adjusted by adjusting the corresponding data line voltage.
In order to solve the above problem, the present invention provides a method for determining a data line voltage, which is applied to a driving chip of a display device, that is, a method for determining an output data line voltage of the driving chip, the method including:
dividing a display panel of the display device into n blocks at an algorithm level, wherein n is a positive integer greater than 2, and the blocks on the display panel have the same reference voltage range and gamma register value; that is, the maximum value and the minimum value of the reference voltages of the plurality of blocks are the same;
dividing the range of the reference voltage of the nth block into equal parts Dn, wherein the value of Dn has a correlation with the power line impedance from the pixel electrode in the block to the driving chip;
and calculating the voltage of the data line applied to the pixel electrode in the nth block according to the maximum value, the minimum value, the gamma register value and the equal part Dn of the reference voltage.
That is to say, the data line voltage determining method provided in the present invention has the same reference voltage range and the same gamma register value for all blocks in the display panel, and the only difference is that the divided equal parts of the reference voltage range in the blocks at different positions are different. The voltage of the data line is converted by the driving chip according to the gamma register value as an analog quantity and then output, an output analog voltage corresponding to the least significant bit lsb (least significant bit) of the gamma register value is used as a unit quantity voltage, and the unit quantity voltage is obtained by equally dividing the voltage difference of the reference voltage Vgmp and Vgsp, namely the unit quantity voltage is determined by (Vgmp-Vgsp)/Dn. It can be seen from theoretical analysis that the data line voltage is related to the gamma register value, the voltage difference between the reference voltages Vgmp and Vgsp, and the fractional number Dn thereof. Under the condition that the gamma register values are the same and the maximum value and the minimum value of the reference voltage range are the same, the data line voltage can be adjusted by adjusting the equal number Dn of the reference voltage range, so that different equal numbers Dn are set according to different impedances of power lines from pixel electrodes to driving chips in different blocks, the data line voltages connected with the pixel electrodes in different blocks are different, different IR voltage drops caused by different impedances of the power lines from the pixel electrodes to the driving chips in different blocks are compensated, and the display brightness uniformity of the display panel is better.
It should be noted that, with respect to the reference voltage range corresponding to different positions, the data line voltage determining method provided by the present invention can realize that the data line voltage of a certain block changes along with the change of the power line impedance from the pixel electrode to the driving chip only by changing the algorithm without changing the hardware circuit structure, and compensate the IR voltage drop caused by the power line impedance; in addition, the data line voltage determining method changes the divided equal parts of the reference voltage range in the blocks, only the block division mode and the data of the divided equal parts of the reference voltage range in each block are needed to be stored in the aspect of data processing, and compared with the method for changing the register value corresponding to the gray scale, the data storage space is smaller.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 3, fig. 3 is a flowchart of a method for determining a data line voltage according to an embodiment of the present invention; the data line voltage determining method is applied to a driving chip of a display device, and comprises the following steps:
s101: dividing a display panel of the display device into n blocks, wherein n is a positive integer greater than 2, and the n blocks have the same maximum value and minimum value of a reference voltage and the same gamma register value;
s102: dividing the range of the reference voltage of the nth block into equal parts Dn, wherein the value of Dn is in a correlation relation with the impedance of a power line from a pixel electrode in the nth block to the driving chip;
s103: and determining the data line voltage of the pixel electrode in the nth block according to the maximum value and the minimum value of the reference voltage, the gamma register value and the Dn.
It should be noted that the power line from the pixel electrode to the driving chip in this embodiment is a PVDD signal line. That is, the value of Dn in this embodiment is related to the impedance from the pixel electrode in the nth block to the power line PVDD of the driving chip. The impedance of the power line in this embodiment is generally related to the material of the power line, the cross-sectional area of the power line, and the length of the power line, so that the compensation of the difference in voltage drop caused by the difference in impedance of the power line in this embodiment does not refer to the voltage drop caused by the difference in length of the power line alone, but refers to the problem of non-uniform display brightness in different areas caused by the difference in impedance of the integrated power line.
When the materials of the power lines connected to all the pixel electrodes are the same and the cross-sectional areas are the same, the greater factor causing the non-uniformity of the display brightness is the length of the power line from the pixel electrode to the driving chip, and in this case, the value Dn may be only related to the length of the PVDD signal line from the pixel electrode to the driving chip. However, if the materials of the power lines from all the pixel electrodes to the driving chip are the same, and the cross-sectional areas and the lengths of the power lines are different, the impedance of the power lines is different under the comprehensive condition of the cross-sectional areas and the lengths of the power lines, and then the value of Dn in this embodiment is related to both the cross-sectional areas and the lengths of the power lines.
Correspondingly, the display panel of the display device is divided into n blocks, and the dividing manner is not limited in this embodiment, for example, when the materials of the power lines from all the pixel electrodes to the driving chip are the same and the cross-sectional areas are the same, the display brightness is less influenced by other factors and mainly influenced by the IR drop caused by the impedance generated by the length of the power lines from the pixel electrodes to the driving chip, so that, in this embodiment, as shown in fig. 4, fig. 4 is a schematic diagram of the dividing manner of the display panel in the double-side driving manner provided in the embodiment of the present invention; because the double-side driving mode is that the driving chip is respectively connected to different pixel electrodes through the left and right power lines, the display panel is bounded by the middle line I, and the display brightness of the display areas AA1 and AA2 on the left and right sides is basically the same, but because the driving chip IC is usually placed at the lower frame position of the display panel, the pixel electrode PS above the display panel is far away from the driving chip, the length of the corresponding power line X1 is long, the resistance R1 is large, and the generated IR voltage drop is large; the pixel electrode PX under the display panel is closer to the driver chip, the length of the corresponding power line X2 is shorter, the resistance R2 is smaller, and the generated IR drop is smaller, so the luminance of the pixel far away from the driver chip is smaller than the luminance of the pixel near the driver chip, i.e., the display luminance above the display panel is darker than the display luminance below the display panel.
Therefore, in this embodiment, the display panel may be divided into n blocks along a direction where a central point of the display panel is connected to a central point of the driving chip, and the n blocks are numbered, and the number of the n blocks may be sequentially numbered as 1, 2, and 3 … … n according to a descending order of power line impedances from the pixel electrodes to the driving chip in the blocks. Referring to fig. 4, since the driving chip is disposed at the lower frame, a connection line between the center point of the display panel and the center point of the driving chip is a Y direction in fig. 4. When the driving chip is located at other positions, similarly, the driving chip may be divided according to the lengths of power lines from the pixel electrodes at different positions in the display panel to the driving chip, and the number of the pixel electrodes corresponding to each block in the n divided blocks may be the same, as shown in fig. 4, the driving chip is sequentially divided into 3 blocks from top to bottom, and the blocks are respectively numbered 1, 2 and 3; in other embodiments, the number of the pixel electrodes corresponding to each of the n divided blocks may also be different, as shown in fig. 5, which is not limited in this embodiment.
In this embodiment, a value of n is not limited, n may be any positive integer greater than or equal to 2, when the value of n is larger, the number of divided blocks is larger, and the data line voltage may be adjusted for each block, so that the adjustment accuracy is higher, and the luminance of all the blocks tends to be uniform, and the uniformity of the display panel is higher. In order to further improve the uniformity of the display brightness in different areas, in this embodiment, the display panel may be further divided into n blocks according to the number of the pixel electrodes, and each block corresponds to at least one pixel. For example, one pixel is divided into one block, or a plurality of pixels are divided into one block. It should be noted that a plurality of pixels or a plurality of pixel units divided into one block may or may not be adjacent, which is not limited in this embodiment.
However, each block corresponds to one value Dn, and when the number of divided blocks is large, the data storage of Dn occupies a certain storage space of the driver chip, and the occupied data storage space is large compared with that of the divided blocks. Therefore, in the actual use process, the number and the position of the division blocks can be adjusted according to the uneven brightness degree of the display panel.
For example, two pixels can be divided into one block to save half the space occupied by the Dn data storage, as compared to dividing one pixel into one block. Specifically, as shown in fig. 6, fig. 6 is a schematic diagram of a display panel adopting a double-side driving manner to divide blocks in this embodiment; because the left and right subareas are symmetrical with respect to the connecting line I between the central point of the display panel and the central point of the driving chip, the lengths of the power lines between the pixel electrodes of the two symmetrical pixels (P1 and P1 ', P2 and P2 ', P3 and P3 ', … …) which are in mirror image relation with the connecting line and the driving chip are the same, and under the condition that the materials and the cross-sectional areas of the power lines are also the same, the two symmetrical pixels can be divided into a block, so that the storage space occupied by half Dn value can be saved, and the uniformity of the display panel can be improved to the maximum extent.
It should be noted that, for the OLED display device, in terms of the current technology, the brightness of the OLED and the PVDD voltage VPVDDThe relationship of (A) is LV>K(VPVDD-Vdata)2That is, the power line far from the driver chip may have a larger impedance, and the voltage drop may be larger, and the PVDD voltage V may be largerPVDDRelatively small so that the corresponding need is to connect the data line voltage VdataAlso adjusted down, and the power line impedance near the driving chip may be smaller, the generated voltage drop is smaller, and the PVDD voltage V is smallerPVDDIs relatively large, so that the data line voltage V is correspondingly requireddataAnd also up-regulated. The data line voltage is determined by the maximum value, the minimum value, the gamma register value and the equal fraction value of the reference voltage, i.e. the data line voltage V of the nth blockdata_nThe following relationship is satisfied:
Vdata_n＝Vgmp-(Vgmp-Vgsp)*d/Dn
wherein, VgmpIs the maximum value of the reference voltage, i.e. the gamma voltage corresponding to the black picture; vgspIs a reference voltage minimum value, i.e., a gamma voltage corresponding to a white picture; d is a gamma register value corresponding to the current gray scale of the pixel unit where the pixel electrode is located, the gamma register value is in the gray scale of 0-255, and each gray scale corresponds to a gamma register value; dn is the number of divided parts of the range of the reference voltage of the nth block; (V)gmp-Vgsp) and/Dn is the output analog voltage corresponding to the least significant bit of the gamma register value, namely the unit quantity voltage.
From the above analysis, it can be known that the data line voltage V of the nth blockdata_nAnd unit quantity voltage (V)gmp-Vgsp) The data line voltage V of the nth block is equal to the data line voltage V of the nth block when the maximum value and the minimum value of the reference voltage range of all blocks are the same and the gamma register value remains the samedata_nIs proportional to the number Dn of the nth block divided by the range of the reference voltage.
Thus, the brightness and PVDD voltage VPVDDThe relationship of (3) can be simplified to the relationship of the luminance LV and the fraction Dn into which the range of the reference voltage of the nth block is divided.
However, it should be noted that, in the case of the OLED display device, the brightness of the OLED and the PVDD voltage VPVDDThe relationship of (A) is LV>K(VPVDD-Vdata)2Correspondingly, when the material of the power line is the same and the cross section area is the same, the impedance of the power line is only related to the length of the power line; pixel electrode pair far away from driving chipThe length of the corresponding power line is longer, the impedance is larger, and the generated voltage drop is also larger, so the corresponding PVDD voltage VPVDDSmaller, in order to make the brightness of the pixel the same as that of other pixels, the voltage V of the data line connected to the pixel electrode needs to be correspondingly reduceddataA value; correspondingly, the division value Dn of the reference voltage of the block where the pixel electrode is located is reduced. That is, the value of Dn is inversely related to the power line impedance from the pixel electrode to the driving chip in the nth block.
Then, for the lcd device, the relationship between the pixel display brightness and the PVDD voltage drop is opposite, and therefore, in other embodiments of the present invention, the value of Dn and the impedance of the power line from the pixel electrode to the driving chip in the nth block may also be in a positive correlation, which is not limited in this embodiment.
It can be derived from the above theory that the method for determining the data line voltage provided by the embodiment of the invention realizes the adjustment of the data line voltage without changing the maximum value and the minimum value of the reference voltage range and the gamma register value, thereby compensating the brightness difference caused by the difference of voltage drops due to the difference of impedances of different pixel power lines and enabling the display brightness of the display device to be more uniform.
Moreover, compared with the adjustment of the reference voltage range and the need of designing a new circuit, the data line voltage determining method provided by the embodiment of the invention can realize brightness compensation only through algorithm adjustment without changing a hardware structure, thereby reducing the cost problem caused by hardware improvement; compared with a scheme of adjusting a gamma register value to compensate brightness, each gray scale corresponds to one gamma register value, each pixel has a gray scale of 0-255 after the gamma register value is modified, and the gamma register value corresponding to each gray scale needs to be correspondingly changed, so that the occupied space of data storage is large.
In order to more clearly illustrate the determination of the reference voltage division equal part Dn value corresponding to each block in the embodiment, the embodiment of the present invention provides a specific implementation method, that is, an approximation method is adopted to finally obtain the division equal part value corresponding to each block.
S102: as shown in fig. 7, fig. 7 is a flowchart of a method for determining a range-divided-portion value of the reference voltage of each block, and the method for determining the range-divided-portion value of the reference voltage of each block specifically includes:
s1021: dividing the range of the reference voltage of each block into equal initial values;
s1022: detecting the display brightness of each block;
s1023: determining target brightness;
s1024: and adjusting the range division equal part value of the reference voltage of each block, so that the difference between the display brightness of each block and the target brightness is within a preset range.
That is, after the display panel is divided into n blocks, the maximum value and the minimum value of the reference voltage corresponding to all the blocks and the gamma register value corresponding to a certain gray scale are determined; then, the reference voltage range of each block is divided into equal initial value portions, which are the same as the divided equal portions of all blocks.
Then, based on the divided equal part value of the reference voltage range, the display brightness of each block is detected, a target brightness is preset, and the divided equal part value of the reference voltage range of each block is adjusted by comparing the display brightness of each block with the target brightness, so that the display brightness of all the blocks is consistent with the target brightness.
In this embodiment, the determination method of the target brightness is not limited, and in order to reduce the number of the adjusted blocks as the same as the habit of the user, optionally, the display brightness of the central block of the display panel is used as the target brightness in this embodiment. That is, the luminance of the block where the pixel electrode at the central area of the display panel is located is determined as the target luminance. Thus, the adjustment of the display brightness of the central block of the display panel, that is, the determination of the range division equal part value of the reference voltage of the central block can be omitted.
After the display brightness of the central block is determined to be the target brightness, according to the
Detecting the display brightness of each block; comparing the target brightness, and if the difference between the display brightness of the ith block and the target brightness is within a preset range, determining the range division equal part value of the current reference voltage of the ith block as Di; and if the difference between the display brightness of the jth block and the target brightness is out of the preset range, continuously adjusting the range of the reference voltage of the jth block to divide equal parts until the difference between the display brightness of the jth block and the target brightness is in the preset range, wherein j is not equal to i.
That is, in the embodiment, the Δ D is used as the adjustment unit of the divided equal value of the reference voltage range, and the divided equal value of the reference voltage range of each block is adjusted step by step until the difference between the display brightness and the target brightness of each block is within the preset range. In this embodiment, the specific value and the positive-negative relationship of Δ D are not limited, and in the specific operation, the adjustment of the display luminance is gradually realized by using an approximation method, and the divided equal parts of the reference voltage range of each block are determined.
In addition, if the difference between the display brightness of the jth block and the target brightness is outside the preset range, the method continues to adjust the range of the reference voltage of the jth block to divide the same into equal parts, and specifically includes: and adjusting the size of delta D in the range division equal parts of the reference voltage of the jth block according to the approaching trend of the display brightness of the jth block and the target brightness. Or adjusting the number of delta D in the range division equal parts of the reference voltage of the jth block according to the approaching trend of the display brightness of the jth block and the target brightness.
That is to say, after the range of the reference voltage is adjusted once to divide the equal parts, if the display brightness of some blocks is not adjusted to the target brightness, the difference between the display brightness of the block and the target display brightness is larger, in the subsequent adjustment process, the adjustment can be performed according to the multiple Δ D, and the approaching speed of the display brightness is accelerated; however, the difference between the display brightness of some blocks and the target brightness is small, and it is possible to adjust one Δ D, and an adjusted situation occurs, for example, when the display brightness is smaller than the target brightness and becomes larger than the target brightness, the size of Δ D can be reduced by adjusting the size of Δ D, so that the display brightness of the block is closer to the target brightness, and the problem that the display brightness cannot be adjusted in place all the time due to Δ D being a fixed adjustment unit is avoided.
According to the embodiment of the invention, by the data line voltage determining method, the data line voltage is adjusted by adjusting the divided equal parts of the reference voltage range in each block, so that the display brightness corresponding to the block is the same as the target brightness, and the aim of improving the overall display uniformity of the display panel is fulfilled.
Based on the same inventive concept, as shown in fig. 8, a schematic diagram of a data line voltage determining apparatus provided for an embodiment of the present invention is shown, where the data line voltage determining apparatus is located in a driving chip of a display apparatus, and the data line voltage determining apparatus includes:
a
a reference
and the data line
It should be noted that the data line voltage determining device provided in the embodiment of the present invention is located in a driving chip of the display device, and the data line voltage corresponding to the pixel electrode in each block is finally obtained through algorithm and logic control in the driving chip.
The working principle of the data line voltage determining apparatus in this embodiment may refer to the specific process of the data line voltage determining method, which is not described in detail in this embodiment.
Based on the same inventive concept, an embodiment of the present invention further provides a driving method, which is applied to a display device, as shown in fig. 9, where fig. 9 is a flowchart of the driving method provided by the embodiment of the present invention; the driving method includes:
s201: determining a block where the pixel electrode is located;
s202: outputting the data line voltage corresponding to the pixel electrode according to the preset relation between the block and the data line voltage, and driving the pixel electrode to display;
wherein the data line voltage is determined using the data line voltage determination method described in the above embodiment.
That is, when the data line voltage is provided for each pixel electrode, the block where the pixel electrode is located is determined, and then the corresponding data line voltage is output according to the data line voltage corresponding to the block where the pixel electrode is located, so that the display brightness in each block in the display panel is similar or identical, and the uniformity of the display panel is improved.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in an article or device that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
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