This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 103110147 filed in Taiwan, Republic of China on Mar. 18, 2014, the entire contents of which are hereby incorporated by reference.
1. Field of Invention
The invention relates to a display device and driving method thereof and, in particular, to an organic light-emitting diode (OLED) display device and driving method thereof.
2. Related Art
Flat display apparatuses, having advantages such as low power consumption, less heat, light weight and non-radiation, are widely applied to various electronic products and gradually take the place of cathode ray tube (CRT) display apparatuses. A flat display apparatus can be divided into a passive matrix type and an active matrix type according to its driving method. Limited to the driving method, the passive matrix display apparatus is short of a long lifespan and unfavorable to a large-scale production. Although the active matrix display apparatus is made by an advanced technology with the higher cost, it is suitable for the large-scale and high-definition full color display with a large information capacity and therefore has become the mainstream of the flat display apparatus. For the active matrix display device, the matrix OLED display device is getting more and more popular recently.
However, due to some factors such as the variation of process, material or element characteristic, the threshold voltage (Vth) of the driving transistors applied to the active OLED display device for driving OLEDs may be shifted, and therefore the driving currents of the OLEDs of the pixels may be slightly different in magnitude even though the same data voltage is provided for driving. Consequently, the displayed image will have the problem of uneven brightness (such as Mura effect).
Accordingly, in the conventional art, a pixel compensation circuit is used to compensate the shift of the threshold voltage of the driving transistor to avoid the uneven brightness of the image. For the conventional pixel compensation, a so-called sequential compensation technique is to compensate the pixels of a row at one time according to the scanning sequence of the scan lines in the timing operation of the TFT circuit. However, this kind of compensation will increase the quantity of the signal circuit along the scanning direction and also the quantity of the driving IC (i.e. the gate driver).
For reducing the quantity of the above-mentioned signal circuit and driving IC, another compensation technique is proposed to connect the all signal circuits required for the compensation together to implement one-time compensation to all the pixels of the panel. However, such kind of one-time compensation will shorten the time for displaying image and lower down the average brightness of the displayed image, and besides, the displayed image will also easily have the flick issue.
Therefore, it is an important subject to provide an OLED display device and the driving method thereof which can reduce the quantity of the scanning signal circuit and driving IC and also can avoid the flick of the displayed image.
In view of the foregoing subject, an objective of the invention is to provide an OLED display device and the driving method thereof which can reduce the quantity of scanning signal circuit and driving IC and also can avoid the flick of the displayed image.
To achieve the above objective, an OLED display device according to the invention includes a display panel, m scan lines, n first control lines, n second control lines and a compensation driving circuit. The display panel includes a plurality of pixel units arranged in a matrix formed by columns and rows. Each of the pixel units has a compensation circuit. The pixel units are arranged into m rows of the matrix, and pixel units of the rows are divided into n groups. The scan lines are disposed corresponding to and electrically connected with the pixel units of the rows. The first control lines and the second control lines are disposed corresponding to the groups and electrically connected with the pixel units of the corresponding groups. The ratio (m/n) is a positive integer, and 2≦(m/n)<m. The compensation driving circuit is electrically connected with the pixel units through the scan lines, the first control lines and the second control lines.
To achieve the above objective, a driving method of an OLED display device of the invention is disclosed. The OLED display device includes a display panel, m scan lines, n first control lines, n second control lines and a compensation driving circuit, the display panel includes a plurality of pixel units arranged in a matrix formed by columns and rows, each of the pixel units has a compensation circuit, and the compensation driving circuit is electrically connected with the pixel units through the scan lines, the first control lines and the second control lines. The driving method comprises a step of: driving the pixel units sequentially through the first control lines, the second control lines and the scan lines by the compensation driving circuit, wherein the pixel units are arranged into m rows of the matrix, the pixel units of the rows are divided into n groups, the scan lines are disposed corresponding to and electrically connected with the pixel units of the rows, the first control lines and the second control lines are disposed corresponding to the groups and electrically connected with the pixel units of the corresponding groups, and the ratio (m/n) is a positive integer and 2≦(m/n)<m.
As mentioned above, in the OLED display device and driving method thereof according to the invention, the pixel units are arranged into m rows, and pixel units of the rows are divided into n groups. Besides, the scan lines are disposed corresponding to and electrically connected with the pixel units of the rows. The first control lines and the second control lines are disposed corresponding to the groups and electrically connected with the pixel units of the corresponding groups. The ratio (m/n) is a positive integer, and 2≦(m/n)<m. Thereby, the OLED display device and the driving method thereof according to the invention not only can reduce the quantity of the scanning signal circuit and driving IC but also can avoid the flick of the displayed image.
The invention will become more fully understood from the detailed description and accompanying drawings, which are given for illustration only, and thus are not limitative of the present invention, and wherein:
The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
As shown in
The display panel 11 includes a plurality of pixel units 111, which are arranged in a matrix formed along a column direction and a row direction. For example, the above column direction is the vertical direction in
There are m rows of the pixel units 111 and the pixel units 111 of the rows are divided into n groups G1˜Gn. Each of the groups has the same number of the rows and therefore has the same number of the pixel units 111. In other words, by regarding the row as a unit, the pixel units 111 of the all rows are divided averagely into n groups G1˜Gn along the column direction, so that each of the groups has the same number of the pixel units 111. Moreover, the compensation driving circuit 12 is electrically connected with the pixel units 111 of the display panel 11 through the scan liens S1˜Sm, the first control lines CL11˜CL1n and the second control lines CL21˜CL2n. In this embodiment, the pixel unit 111 is a 3T2C circuit structure for example, so the compensation driving circuit 12 is electrically connected with the all pixel units 111 of the same row through a scan line and electrically connected with the all pixel units 111 of the same group through a first control line (such as the compensation signal line) and a second control line (such as the signal line for controlling the lighting of the OLED). To be noted, the number of the control lines is not limited in this invention, and it may change according to the number of the elements used in the compensation driving circuit. Herein for example, there are two control line groups, indicating n first control lines CL11˜CL1n and n second control lines CL21˜CL2n.
The first control lines CL11˜CL1n and the second control lines CL21˜CL2n are disposed corresponding to the groups G1˜Gn and electrically connected with the pixel units 111 of the corresponding groups. In this embodiment, each of the groups has three rows of the pixel units 111 and therefore the number of the pixel units 111 of each group is 3*p (due to p columns). However, in other embodiments, each group can have the rows of a different quantity, and for example, 2 rows, 4 rows or others, so that the all pixel units 111 are divided into the groups of different numbers. The scan lines S1˜Sm are disposed corresponding to and electrically connected with the pixel units 111 of the rows. Herein as shown in
The data driving circuit 13 is electrically connected with the pixel units 111 of the display panel 11 through the data lines D1˜Dp, and the timing control circuit 14 is electrically connected with the compensation driving circuit 12 and the data driving circuit 13. The timing control circuit 14 can transmit the vertical clock signal and the vertical synchronization signal to the compensation driving circuit 12, convert the image signal received through the external interface into the data signal used by the data driving circuit 13, and transmit the data signal, horizontal clock signal and horizontal synchronization signal to the data driving circuit 13. Besides, the compensation driving circuit 12 drives the pixel units 111 through the first control lines CL11˜CL1n, the second control lines CL21˜CL2n and the scan lines S1˜Sm sequentially. Herein, the compensation driving circuit 12 sequentially enables the scan lines S1˜Sm according to the vertical synchronization signal. Besides, before the compensation driving circuit 12, through a scan line, enables the pixel units 111 of the corresponding row, the compensation driving circuit 12 drives the pixel units 111 corresponding to the scan line through the first control lines CL11˜CL1n and the second control lines CL21˜CL2n to implement the pixel compensation and control the lighting of the OLED. The compensation driving circuit 12 implements the compensation to the shift of threshold voltage of TFT of the pixel units 111 through the first control lines CL11˜CL1n or the second control lines CL21˜CL2n. When the scan lines S1˜Sm are sequentially enabled, the data driving circuit 13 can transmit the pixel voltage signals corresponding to the pixel units 111 of each row to the corresponding pixel units 111 through the data lines D1˜Dp so that the display device 1 can display images.
As shown in
Moreover, the OLED display device 1 can further include at least one multiplexing unit disposed in the peripheral area BB. Herein for example, two multiplexing units 151, 152 are disposed on the opposite two sides of the peripheral area BB of the display panel 11, respectively (of course, only one multiplexing unit 151 can be used). The compensation driving circuit 12 of the driving unit 2 can be electrically connected with the scan lines S1˜Sm (not shown), the first control lines CL11˜CL1n (not shown), the second control lines CL21˜CL2n (not shown) and the pixel units 111 through the multiplexing units 151, 152.
As shown in
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The above-mentioned first selection signal C1, second selection signal C2 and third selection signal C3 can be outputted by the timing control circuit 14 or the driving unit 2.
The main difference from the OLED display device 1 is that the OLED display device 1a can further include n third control lines CL31˜CL3n, which are disposed corresponding to the groups G1˜Gn and electrically connected with the pixel units 111 of the corresponding groups G1˜Gn. Herein, the pixel unit 111 of the OLED display device 1a is a 4T2C circuit structure for example, so the compensation driving circuit 12 is electrically connected with the all pixel units 111 of the same row through a scan line and electrically connected with the all pixel units 111 of the same group through a first control line (such as the compensation signal line), a second control line (such as the signal line controlling the lighting switch of the OLED) and a third control line (such as a reset signal line).
The driving process and other technical features of the OLED display device 1 can be comprehended by referring to the OLED display device 1 and therefore the related descriptions are omitted here for conciseness.
As below, refer to
The driving method of the OLED display device 1 includes the step S01 of driving the pixel units 111 sequentially through the first control lines CL11˜CL1n, the second control lines CL21˜CL2n and the scan lines S1˜Sm by the compensation driving circuit 12, wherein the pixel units 111 are arranged into m rows, the pixel units 111 of the rows are divided into n groups G1˜Gn, the scan lines S1˜Sm are disposed corresponding to and electrically connected with the pixel units 111 of the rows, the first control lines CL11˜CL1n and the second control lines CL21˜CL2n are disposed corresponding to the groups G1˜Gn and electrically connected with the pixel units 111 of the corresponding groups G1˜Gn, and the ratio (m/n) is a positive integer and 2≦(m/n)<m.
Before the compensation driving circuit 12, through a scan line, enables the pixel units 111 of the corresponding row, the compensation driving circuit 12 implements the compensation to the shift of the threshold voltage of the TFTs of the pixel units 111 of the corresponding group through the first control lines CL11˜CL1n or the second control lines CL21˜CL2n. By taking the first scan line S1 as an example, before the scan line S1 enables the corresponding pixel units 111 of the first row, the compensation driving circuit 12 can implement the compensation to the shift of the threshold voltage of the TFTs of the all pixel units 111 of the first group G1 (three rows totally) through the first control line CL11 (or the second control line CL21). Then, before the scan line S2 enables the corresponding pixel units 111 of the second row, the compensation driving circuit 12 can implement the compensation to the shift of the threshold voltage of the TFTs of the all pixel units 111 of the second group G2 (three rows totally) through the first control line CL12 (or the second control line CL22). The rest can be deduced by analogy.
Furthermore, when the scan lines S1˜Sm are enabled sequentially, the data driving circuit 13 can transmit the pixel voltage signals corresponding to the pixel units 111 of each row to the corresponding pixel units 111 through the data lines D1˜Dp, and therefore the display device 1 can display images.
During a frame time, the pixel units 111 have three stages: a compensation stage, a write-in stage of pixel voltage and a display stage of image. By comparing
By taking a physical embodiment as an example, when the OLED display device 1 has 480 scan liens (m=480), there are totally 160 groups (n=160) if a group has three rows (i.e. (m/n=3)), so the signal circuit for scanning, i.e. including the scan lines, first control lines and second control lines, just has 800 (i.e. 480+(480/3)+(480/3)) lines. However, for the sequential compensation, there will be 1440 (480 scan lines+480 first control lines+480 second control lines) lines of the scan signal circuit totally. Therefore, the invention can reduce the quantity of the signal circuit by 640 lines.
In other embodiments, if 4 rows are a group (i.e. (m/n)=4), there will be 120 groups (n=120), and therefore this invention only has 720 (480+(480/4)+(480/4)) lines for the scan signal circuit, less than the sequential compensation by 720 lines.
Furthermore, for the structure of the OLED display device 1a in
Since other technical features of the driving method of the OLED display device have been clearly illustrated in the above, the related description is omitted here for conciseness.
Summarily, in the OLED display device and driving method thereof according to the invention, the pixel units are arranged into m rows, and pixel units of the rows are divided into n groups. Besides, the scan lines are disposed corresponding to and electrically connected with the pixel units of the rows. The first control lines and the second control lines are disposed corresponding to the groups and electrically connected with the pixel units of the corresponding groups. The ratio (m/n) is a positive integer, and 2≦(m/n)<m. Thereby, the OLED display device and the driving method thereof according to the invention not only can reduce the quantity of the scanning signal circuit and driving IC but also can avoid the flick of the displayed image.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.
Number | Date | Country | Kind |
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103110147 | Mar 2014 | TW | national |