Patent Application
20240290242
This application claims the priority and benefit of Chinese patent application number 202310231477X, titled “Driving Method of Display Device, and Display Device” and filed Feb. 28, 2023 with China National Intellectual Property Administration, the entire contents of which are incorporated herein by reference.
The present application relates to the field of display technology, and in particular, to a driving method of a display device and a display device.
The description provided in this section is intended for the mere purpose of providing background information related to the present application but doesn't necessarily constitute prior art.
With the improvement of the quality of life, LED display screens put forward higher requirements for row driving, from simple P-channel Metal-Oxide-Semiconductor Field-Effect Transistor (PMOSFET) that realizes row switching, to multi-functional row drivers with higher integration and stronger functions.
When the data signal of the control row is low, the voltage on the row line (that is, the anode voltage of the LED light) will be pulled high, and the data of the column tube (which can be understood as the voltage on the cathode of the LED light) will be displayed. The low-level data signals with different widths will get different LED light brightnesses. However, due to the existence of parasitic capacitance, the current discharged by the parasitic capacitance remains unchanged during display, resulting in different proportions of the currents flowing through the LEDs to those entering the data driving chip, resulting in color shift.
In view of the above, it is therefore one purpose of the present application to provide a driving method of a display device and a display device, which can solve the problem of color shift caused by parasitic capacitance by compensating the display grayscale of the instant row.
The present application discloses a driving method of a display device. The display device includes scan lines, data lines, and a plurality of LED lights driven by the scan lines and data lines. The plurality of LED lights are arranged in multiple rows and columns. An anode of each LED is connected to the respective scan line. A cathode of each LED is connected to the respective data line. The driving method includes:
In some embodiments, the operation of obtaining the compensated display grayscale corresponding to the LED in the instant row according to the display grayscale of the LED in the previous row, the display grayscale of the LED in the instant row and the display grayscale compensation table includes:
In some embodiments, the display device includes an LED current generation circuit. Each data line is correspondingly connected to an LED current generation circuit. The LED current generation circuit includes a data register, a digital-to-analog converter and a control switch. A gate terminal of the control switch is connected to the data register through the digital-to-analog converter. A source of the control switch is connected to a reference low level. A drain of the control switch outputs the LED current. The operation of obtaining the corresponding driving parameters according to the compensated display grayscale corresponding to the LED in the instant row includes:
In some embodiments, the operation of obtaining the compensated display grayscale corresponding to the LED in the instant row according to the display grayscale of the LED in the previous row, the display grayscale of the LED in the instant row, and the display grayscale compensation table includes:
In some embodiments, the operation of obtaining the compensated display grayscale corresponding to the LED in the instant row according to the display grayscale of the LED in the previous row and the display grayscale of the LED in the instant row and the display grayscale compensation table includes:
In some embodiments, the LED lights include a red LED light, a green LED light, and a blue LED light, and the operation of obtaining the compensated display grayscale corresponding to the LED in the instant row according to the display grayscale of the LED in the previous row, the display grayscale of the LED in the instant row, and the display grayscale compensation table includes:
In some embodiments, the display device includes a data driving chip. The data driving chip outputs driving parameters to the data line. The operation of obtaining the compensated display grayscale corresponding to the LED in the instant row according to the display grayscale of the LED in the previous row, the display grayscale of the LED in the instant row and the display grayscale compensation table includes:
In some embodiments, the parasitic capacitance is C1, the parasitic capacitance between the data line and the ground wire is C2, the parasitic capacitance between the data line and the scan line is C3, and the parasitic capacitance in the LED light is C4, and C1=C2+C3+C4.
In some embodiments, the display grayscale is the display grayscale of the data line, and the driving method further includes:
The application further discloses a display device. The display device is driven by any of the driving methods described above. The display device includes scan lines, data lines, and a plurality of LED lights driven by the scan lines and data lines. The plurality of LED lights are arranged in multiple rows and columns. An anode of the LED is connected to the respective scan line. A cathode of the LED is connected to the respective data line. The display device further includes a storage module and a driving parameter generation module. The storage module is used to store the display grayscale compensation table. The driving parameter generation module generates corresponding driving parameters according to the compensated display grayscale corresponding to the LED in the instant row to control the display of the LED lights of the display device.
This application considers that parasitic capacitance will be generated after the display of the LED in the previous row, and the generated parasitic capacitance will affect the display of the next row of LEDs, and so the present application adjusts the display grayscale of the LED in view of the influence of the parasitic capacitance. In particular, the display grayscale of the LED light in the previous row and the display grayscale of the LED light in the instant row are obtained, and then the compensated display grayscale corresponding to the LED in the instant row is obtained through the stored display grayscale compensation table. Further, the corresponding driving parameters are obtained according to the compensated display grayscale corresponding to the LED in the instant row. Accordingly, the display of LEDs in the instant row is controlled through the driving parameters. Because the driving parameters obtained by the display grayscale compensation table already include the influence of parasitic capacitance on the image, the color shift problem has been improved and resolved when LED is displayed.
The accompanying drawings are used to provide a further understanding of the embodiments according to the present application, and constitute a part of the specification. They are used to illustrate the embodiments according to the present application, and explain the principle of the present application in conjunction with the text description. Apparently, the drawings in the following description merely represent some embodiments of the present disclosure, and for those having ordinary skill in the art, other drawings may also be obtained based on these drawings without investing creative efforts. A brief description of the accompanying drawings is provided as follows.
In the drawings: 100, display device; 110, scan line; 120, data line; 130, LED light; 140, storage module; 150, driving parameter generation module; 151, LED current generation circuit; 152, data register; 153, digital-analog converter; 154, control switch; 160, driving switch.
It should be understood that the terms used herein, the specific structures and function details disclosed herein are intended for the mere purposes of describing specific embodiments and are representative. However, this application may be implemented in many alternative forms and should not be construed as being limited to the embodiments set forth herein.
As used herein, terms “first”, “second”, or the like are merely used for illustrative purposes, and shall not be construed as indicating relative importance or implicitly indicating the number of technical features specified. Thus, unless otherwise specified, the features defined by “first” and “second” may explicitly or implicitly include one or more of such features. Terms “multiple”, “a plurality of”, and the like mean two or more. Term “comprising”, “including”, and any variants thereof mean non-exclusive inclusion, so that one or more other features, integers, steps, operations, units, components, and/or combinations thereof may be present or added.
In addition, terms “center”, “transverse”, “up”, “down”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, or the like are used to indicate orientational or relative positional relationships based on those illustrated in the drawings. They are merely intended for simplifying the description of the present disclosure, rather than indicating or implying that the device or element referred to must have a particular orientation or be constructed and operate in a particular orientation. Therefore, these terms are not to be construed as restricting the present disclosure.
Furthermore, as used herein, terms “installed on”, “mounted on”, “connected to”, “coupled to”, “connected with”, and “coupled with” should be understood in a broad sense unless otherwise specified and defined. For example, they may indicate a fixed connection, a detachable connection, or an integral connection. They may denote a mechanical connection, or an electrical connection. They may denote a direct connection, a connection through an intermediate, or an internal connection between two elements. For those of ordinary skill in the art, the specific meanings of the above terms as used in the present application can be understood depending on specific contexts.
Hereinafter this application will be described in further detail with reference to the accompanying drawings and some optional embodiments.
As shown in
After the display of the LED in the previous row ends, the corresponding parasitic capacitances are also charged. Due to the existence of parasitic capacitance, when the instant row is displayed, the current discharged by the parasitic capacitance remains unchanged, resulting in a different proportion of the current flowing through the LED and entering the driving parameter generation module 150 (also called MBI LED-Driver IC, LED data driving chip), resulting in color shift. This phenomenon is more severe especially for low grayscales, because the proportion of the current on the parasitic capacitance entering the Driver IC becomes larger, and so the phenomenon is naturally more obvious. This application obtains the compensated display grayscale corresponding to the LED in the instant row based on the display grayscale of the LED in the previous row 130, the display grayscale of the LED in the instant row 130 and the display grayscale compensation table, and so the driving parameters corresponding to the compensated display grayscale have actually taken into account the problem of parasitic capacitance. When the driving parameters corresponding to the compensated display grayscale are used to drive the LED lights 130 for display, the problem of color shift is improved and resolved.
Further, it should be noted that in the generation of the display grayscale compensation table, specifically, as shown in
The above operations can also be understood as the generation operations of the display grayscale compensation table. The display grayscale compensation table calculates the compensation value for the LED display grayscales of the instant row based on the display grayscale of the LED in the previous row, the corresponding parasitic capacitance and the display grayscales of the instant row. The display grayscale compensation table is as shown in Table 1 below:
In the above table 1, there is shown the data voltages (64 grayscales, corresponding to 6 bits of data) that need to be output corresponding to the grayscales of the previous row and the grayscales of the instant row. Gray(n) indicates the grayscale displayed by LED in the same column of the previous row, and Gray(m)′ is the grayscale to be displayed in the same column of the instant row. Before the mass production of the product, the most suitable table will be debugged according to the display needs of the form. The table will be adjusted based on the display requirements to obtain the most suitable table. For example, if the grayscale displayed in the previous row is Gray2′, and the grayscale displayed in the instant row is Gray0, then the display grayscale of the instant row after compensation is the grayscale of V02 in the table. Because the display grayscale V02 already includes the influence of parasitic capacitance on the image, the problem of color shift is solved.
In operation S1, the compensated display grayscale corresponding to the LED in the instant row may be obtained based on the original display grayscale of the LED in the previous row 130, the original a display grayscale of the LED in the instant row 130 and the display grayscale compensation table, or the compensated display grayscale corresponding to the LED in the instant row may be obtained based on the compensated display grayscale of the LED in the previous row 130, the original a display grayscale of the LED in the instant row 130 and the display grayscale compensation table.
In addition, if the total amount of parasitic capacitance contributing to the effect is C1, the parasitic capacitance between the data line 120 and the ground wire is C2, the parasitic capacitance between the data line 120 and the scan line 110 is C3, and the parasitic capacitance in the LED light 130 is C4, then C1=C2+C3+C4. This application considers all parasitic capacitances, and through the calculation of all parasitic capacitances, the color shift problem caused by all parasitic capacitances is avoided. The compensated display grayscale obtained in the display grayscale compensation table thus formed can completely eliminate the influence of parasitic capacitance.
In addition, when the LED light 130 stops emitting light, no driving parameter is output on the data line 120, then the control terminal voltage of the driving switch 160 of the scan line 110 can be correspondingly reduced to release the parasitic capacitance on the scan line 110. By reducing the control terminal voltage of the driving switch 160, thereby increasing the conduction degree of the driving switch 160, the parasitic capacitance generated by the scan line 110 can be released faster. In addition, when the LED is displayed, the conduction degree of the driving switch 160 can also be changed, thereby changing the voltage at the anode terminal of the LED, thereby changing the magnitude of the current on the LED, and further changing the proportion of the current produced by the parasitic capacitance. That is, a display grayscale compensation table can also be generated corresponding to the scan line 110 and used together with the display grayscale compensation table corresponding to the data line 120, so as to change the influence of the parasitic capacitance on the data line 120 and the scan line 110.
As shown in
Considering that the current is the main factor affecting the display of the LED light 130, the corresponding voltage data is obtained according to the compensated display grayscale corresponding to the LED in the preceding row. Before the LED light 130 is displayed, the data register 152 transmits the stored voltage data to the digital-to-analog converter 153 to generate a corresponding data voltage, and the generated data voltage is used to control the turn-on of the control switch 154 to generate and output the LED current. During the turn-on period of one scan signal, a current signal is output according to the output parameters of the current signal to drive the LED that needs to be lit at present, so that the LED light 130 lights up and displays. The conduction degree of the control switch 154 is controlled by controlling the voltage value of the control terminal of the switch 154, thereby controlling the magnitude of the driving current of the LED, adjusting the ratios of the discharge current of the parasitic capacitor to the current flowing through the LED and to that entering the Driver IC.
Specifically, take one row of LEDs in the display device 100 as an example, because the charges on the parasitic capacitance has a strong correlation with the display of the previous row. For example, in
As shown in
Referring to
Further, as shown in
If the proportion of the current flowing through the red LED is small, the red LED light 130 is less affected by the parasitic capacitance, and the overall color is reddish. If the proportion of the current flowing through the blue LED is small, then the blue LED light 130 is less affected by the parasitic capacitance, and the overall color is bluish. If the proportion of the current flowing through the green LED is small, the green LED light 130 is less affected by the parasitic capacitance, and the overall color is greenish. In
As shown in
The number of rows and the total number of LEDs in the first display region are the same as the number of rows and the total number of LED lights 130 in the second display region. When the display grayscale of the LED in the previous row 130 and the display grayscale of the LED in the instant row 130 in the first display region are the same as the display grayscale of the LED in the previous row 130 and the display grayscale of the LED in the instant row 130 in the second display region, the compensated display grayscale corresponding to the first display grayscale compensation table and the second display grayscale compensation table are different. When the LED light in the previous row is located in the first display region and the LED light in the instant row is located in the second display region, the compensated display grayscale corresponding to the LED in the instant row is obtained according to the compensated display grayscale of the LED in the previous row, the display grayscale of the LED in the instant row and the first display grayscale compensation table.
Considering the influence of wire resistance, the voltage signal or current on the data line will have a certain loss, so the compensation at the end far away from the signal output is different from the end close to the signal output, and so there are different display grayscale compensation tables in the first display region and the second display region. Of course, a display device 100 may not only be provided with two display regions, but may be provided with display regions according to the number of scan lines 110, where one row of scan lines 110 or two rows of scan lines 110 may be defined as a display region. Thus, different display grayscale compensation tables are set depending on the distances between the display region and the signal output end, so as to more accurately solve the color shift problem of each row of LED lights 130.
As shown in
According to the display grayscale of the LED in the previous row 130, the display grayscale of the LED in the instant row 130 and the display grayscale compensation table, the compensated display grayscale corresponding to the LED in the instant row are obtained. When the driving parameters corresponding to the compensated display grayscale are used to drive and display the LED lights 130, the driving parameters are actually changed relative to the driving parameters corresponding to the original display grayscales, and the parasitic capacitance is taken into consideration, so that the parasitic capacitance is taken into account and the current generated by the parasitic capacitance accounts for less current flowing into the input terminal of the driving parameter generation module 150, so as to avoid the current generated by the parasitic capacitance from affecting the current of the LED in the instant row after the LED in the previous row emits light thus resulting in a color shift problem.
It should be noted that the limitations of various operations involved in this solution will not be deemed to limit the order of the operations, provided that they do not affect the implementation of the specific solution, so that the operations written earlier may be executed earlier or they may also be executed later or even at the same time. As long as the solution can be implemented, they should all be regarded as falling in the scope of protection of this application.
It should be noted that the inventive concept of the present application can be formed into many embodiments, but the length of the application document is limited and so these embodiments cannot be enumerated one by one. The technical features can be arbitrarily combined to form a new embodiment, and the original technical effect may be enhanced after the various embodiments or technical features are combined.
The foregoing description is merely a further detailed description of the present application made with reference to some specific illustrative embodiments, and the specific implementations of the present application will not be construed to be limited to these illustrative embodiments. For those having ordinary skill in the technical field to which this application pertains, numerous simple deductions or substitutions may be made without departing from the concept of this application, and shall all be regarded as falling in the scope of protection of this application.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202310231477.X | Feb 2023 | CN | national |
