1. Field of the Invention
The present invention relates to a method of controlling data display on a panel of a display device and a related driving system for the display device, and more particularly, to a method of dynamically controlling the order of displaying data on a panel of a display device and a related driving system for the display device.
2. Description of the Prior Art
A liquid crystal display (LCD), which is a flat panel display having the advantages of low radiation, light weight and low power consumption, is widely used in various information technology (IT) products such as notebook computers, personal digital assistants (PDA), and mobile phones. An active matrix thin film transistor (TFT) LCD is the most commonly used transistor type in LCD families, and particularly in the large-size LCD family. A driving system installed in the LCD includes a timing controller, source drivers and gate drivers. The source and gate drivers respectively control data lines and scan lines, which intersect to form a cell matrix. Each intersection is a cell including crystal display molecules and a TFT. In the driving system, the gate drivers are responsible for transmitting scan signals to gates of the TFTs to turn on the TFTs on the panel. The source drivers are responsible for converting digital image data, sent by the timing controller, into analog voltage signals and outputting the voltage signals to sources of the TFTs. When a TFT receives the voltage signals, a corresponding liquid crystal molecule has a terminal whose voltage changes to equalize the drain voltage of the TFT, which thereby changes its own twist angle. The rate that light penetrates the liquid crystal molecule is changed accordingly, allowing different colors to be displayed on the panel.
The normal operation always scans the scan lines on the LCD panel to turn on the TFTs row by row in a fixed order from up to down, and the data lines on the LCD panel are charged to specific voltage levels, to output the image data to the turned-on TFTs. In this manner, most power consumption of the LCD device is generated by charging the data lines. With increasing demands of large scale TFT LCD panels and high resolution requirements, more and more cells are included in an LCD panel; this increases power consumption much more. Thus, how to reduce power consumption of the LCD panel has become an important issue in this art.
It is therefore an objective of the present invention to provide a method of controlling data display on a panel of a display device, in order to reduce power consumption of the display device.
The present invention discloses a method of controlling data display on a panel. The method comprises displaying a first row data by turning on a first scan line; comparing a plurality of row data with the first row data, to generate a comparison result; determining an order of displaying the plurality of row data according to the comparison result; and outputting the plurality of row data and turning on a plurality of scan lines corresponding to the plurality of row data in the order, to display the plurality of row data in the order.
The present invention further discloses a driving system for a display device. The driving system comprises a gate driver, at least one source driver and a timing controller. The gate driver is used for turning on a first scan line to display a first row data on a panel of the display device. The at least one source driver is used for outputting a plurality of row data after the first row data is displayed. The timing controller comprises a data comparison unit and a control unit. The data comparison unit is used for comparing the plurality of row data with the first row data, to generate a comparison result. The control unit is used for determining an order of displaying the plurality of row data according to the comparison result, and controlling the at least one source driver to output the plurality of row data and the gate driver to turn on a plurality of scan lines corresponding to the plurality of row data in the order.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Please refer to
Please note that in a driving system of a display device such as the driving system 120, most power consumption originates from charging of the data lines. Larger data variations may usually need more electric charge quantity, and thereby consumes more power. Therefore, in order to reduce power consumption by reducing the degree of data variations, the present invention detects the data variations and changes the order of displaying row data.
Please keep referring to
Please refer to
Step 200: Start.
Step 202: Display a first row data by turning on a first scan line.
Step 204: Compare a plurality of row data with the first row data, to generate a comparison result.
Step 206: Determine an order of displaying the plurality of row data according to the comparison result.
Step 208: Output the plurality of row data and turn on a plurality of scan lines corresponding to the plurality of row data in the order, to display the plurality of row data in the order.
Step 210: End.
According to the data display process 20, the panel 100 first displays a first row data when the gate driver 102 turns on a first scan line. The data comparison unit 112 compares a plurality of row data to be displayed with the first row data, to generate a comparison result. The control unit 114 then determines an order of displaying the plurality of row data according to the comparison result, where the display order may lead to fewer data variations and thereby generate lower power consumption. Accordingly, the source driver 104 will output the plurality of row data in this order, and the gate driver 102 will turn on the plurality of scan lines corresponding to the plurality of row data in this order, so that the plurality of row data are displayed in this order.
More specifically, the control unit 114 may determine a difference between each of the plurality of row data and the first row data by comparing each of the plurality of row data with the first row data, respectively. In this manner, the control unit 114 is able to find out a row data most similar to the first row data (i.e., the row data with a smaller difference to the first row data) from the plurality of row data, and the panel 100 displays this row data after the first row data is displayed. The panel 100 then displays a row data secondarily similar to the first row data. Among the plurality of row data, a row data having a smaller difference to the first row data is displayed earlier than another row data having a larger difference to the first row data, in order to minimize power consumption. For example, the gate driver may turn on a second scan line among the plurality of scan lines to display a second row data among the plurality of row data before turning on a third scan line among the plurality of scan lines to display a third row data among the plurality of row data when the difference between the second row data and the first row data is less than the difference between the third row data and the first row data.
In an embodiment, the timing controller 106 may control the panel 100 to display a row data D0 in the scan line SC_N and then determine that a row data D1 in the scan line SC_(N+1) or a row data D2 in the scan line SC_(N+2) will be displayed following the row data D0. The data comparison unit 112 then compares the row data D1 and D2 with the latest displayed row data D0. In detail, the data comparison unit 112 compares the row data D1 with the row data D0 and finds out the difference between the row data D1 and the row data D0. The data comparison unit 112 also compares the row data D2 with the row data D0 and finds out the difference between the row data D2 and the row data D0. If the difference between the row data D1 and the row data D0 is less than the difference between the row data D2 and the row data D0, the panel 100 displays the row data D1 before displaying the row data D2. If the difference between the row data D2 and the row data D0 is less than the difference between the row data D1 and the row data D0, the panel 100 displays the row data D2 before the row data D1. In contrast to the conventional display device where the row data are always displayed in a fixed order from up to down, the present invention may change the display order, e.g., reverse the order of displaying the row data D1 and D2, to reduce power consumption since the row data with a smaller difference are displayed successively to reduce the amounts of charging and discharging in data lines.
Please note that when the source driver 104 outputs the row data based on the order determined by the timing controller 106, the gate driver 102 may also turn on the scan lines in this order correspondingly. For example, if the source driver 104 outputs the row data in an order of D0, D1 and D2, the gate driver 102 may correspondingly turn on the scan lines in an order of SC_N, SC_(N+1) and SC_(N+2), to display the row data D0, D1 and D2. If the source driver 104 outputs the row data in an order of D0, D2 and D1, where the row data D2 is displayed before the row data D1 since the row data D2 has a smaller difference to the row data D0, the gate driver 102 may correspondingly turn on the scan lines in an order of SC_N, SC_(N+2) and SC_(N+1), to display the row data D0, D2 and D1. That is, in contrast to the conventional data display method where image data is always displayed from up to down, the order of displaying the row data D1 and D2 may be reversed if the reversion leads to reduction of power consumption.
After the plurality of compared row data are displayed, the row data last displayed among the plurality of row data will become the latest row data, which is further compared with a subsequent plurality of row data. More specifically, in the above embodiment, if the panel 100 displays the row data in an order of D0, D1 and D2, the row data D2 will become the latest row data and will be compared with the row data in the scan lines SC_(N+3), SC_(N+4) or other subsequent data lines. If the panel 100 displays the row data in an order of D0, D2 and D1, the row data D1 will become the latest row data and will be compared with the row data in the scan lines SC_(N+3), SC_(N+4) or other subsequent data lines. In this manner, the timing controller 106 may determine the display order in every two row data (or more than two row data), and the panel 100 may display the row data in an order with less data variation or difference in the data lines. This generates less power consumption in every two (or more) row data, and may bring about significant power reduction in image display.
The abovementioned operations of comparing the row data D1 and D2 with the row data D0 to determine the display order may be summarized into a data display process 30, as shown in
Step 300: Start.
Step 302: The source driver 104 outputs the row data D0 and the gate driver 102 turns on the scan line SC_N, to display the row data D0.
Step 304: The timing controller 106 compares the row data D1 and D2 with the latest displayed row data D0, and determines whether the difference between the row data D2 and the row data D0 is less than the difference between the row data D1 and the row data D0. If yes, go to Step 306; otherwise, go to Step 310.
Step 306: The source driver 104 outputs the row data D2 and the gate driver 102 correspondingly turns on the scan line SC_(N+2), to display the row data D2.
Step 308: The source driver 104 outputs the row data D1 and the gate driver 102 correspondingly turns on the scan line SC_(N+1), to display the row data D1, and go to Step 304 to compare the latest displayed row data D1 with subsequent row data.
Step 310: The source driver 104 outputs the row data D1 and the gate driver 102 correspondingly turns on the scan line SC_(N+1), to display the row data D1.
Step 312: The source driver 104 outputs the row data D2 and the gate driver 102 correspondingly turns on the scan line SC_(N+2), to display the row data D2, and go to Step 304 to compare the latest displayed row data D2 with subsequent row data.
In this manner, every two scan lines and the corresponding row data may be classified into a group, and compared with the latest displayed row data. The data display process 30 may be performed in each group, allowing the row data in each group to be displayed in an order so that the data lines possess smaller amounts of charging and discharging, which bring about less power consumption. Please note that a group may also include more than two row data and corresponding scan lines, to achieve further improvements in power reduction, where the number of row data included in a group should be controlled without influencing the quality of displayed image and increasing the cost excessively.
Please refer to
As illustrated by the normal scan method shown in
Please note that in the above embodiments, the comparison between row data is performed on the entire row data. In several embodiments, the comparison between row data is performed on partial row data. More specifically, the panel may be divided into several regions, and the comparison of row data is performed with the partial row data located in each region. Therefore, the difference between the row data to be displayed and the latest displayed row data in each region is determined, respectively.
For example, please refer to
In detail, the order of displaying the row data is determined by incorporating the differences between each row data to be displayed and the latest displayed row data in different regions. In an embodiment, the differences obtained in all regions are obtained to determine whether to reverse the order of displaying two row data such as the row data D1 and D2 shown in
Please refer to
Please note that the current trend of LCD panel is large scale and high resolution, which requires more source drivers to drive a larger number of data lines. Therefore, it is preferable to include more source driver integrated circuits (ICs) in a driving system of an LCD, where each driver IC is responsible for a part of data lines in partial area of the panel. In such a condition, the panel is divided into multiple regions based on the allocation of data lines thereon to each driver IC. In other words, the number of regions may be equal to the number of source drivers implemented in a driving system, and each region is corresponding to one source driver.
In this case, the order of displaying the row data may be determined by considering partial or all of the source driver ICs. In other words, each of the source drivers is able to determine whether to perform row data reversion in order to meet specific requirements. For example, each of the source driver ICs may include a temperature sensor to detect the temperature in the corresponding region. If the temperature detected by one or several source driver ICs exceeds a predetermined level to be regarded as an over-temperature condition, only the region(s) corresponding to this (these) source driver IC(s) is considered to determine whether to perform row data reversion. That is, the order of displaying the row data is determined by incorporating the differences between each of the row data to be displayed and the latest displayed row data only in the region(s) where over-temperature occurs.
Please keep referring to
Please note that the present invention aims at reducing power consumption of a display device by reducing transient power on data lines, which is achieved by dynamically controlling the order of displaying data lines on the panel to allow data lines with less data difference to be displayed successively, so that the electric power for charging the data lines can be decreased. Based on the above operations, those skilled in the art may perform modifications and alternations according to system requirements. For example, the number of row data compared with the latest displayed row data may be two, three or any possible number. The panel may be divided into any number of regions, based on the number of source driver ICs implemented in the driving system or due to other reasons; this should not be limited herein. Furthermore, the circuit structure implemented with the resistors shown in
Please refer to
As illustrated by the normal scan method shown in
In the prior art, the normal operation always scans the scan lines on the LCD panel to turn on the TFTs row by row in a fixed order from up to down, and the data lines on the LCD panel are charged to specific voltage levels, to output the image data. Most power consumption of the LCD device is generated by charging the data lines. The trend of large scale and high resolution in LCD panels is accompanied by more and more power consumption. Therefore, the present invention provides a method of controlling data display on a panel of a display device and the driving system driving the display device. According to embodiments of the present invention, several row data to be displayed are compared with the latest displayed row data, to obtain the difference between each of the row data to be displayed and the latest displayed row data. Therefore, the row data having a smaller difference to the latest displayed row data will be displayed earlier than those having a larger difference to the latest displayed row data. In such a condition, the row data with fewer data variations are displayed successively, which reduces the amounts of charging and discharging operations included in data lines, and thereby reduces power consumption. As a result, the interchange or reversion of the display order of row data may lead to reduction of power consumption after the comparisons between row data are performed. Furthermore, the panel may be divided into several regions, and the comparison of row data is performed in each region. Therefore, the difference between the row data to be displayed and the latest displayed row data located in each region is determined, respectively, and the comparison result in each region is considered to prevent occurrence of over-temperature in specific region(s).
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.