This application claims the benefit of Taiwan application Serial No. 100104339, filed Feb. 9, 2011, the subject matter of which is incorporated herein by reference.
1. Field of the Invention
The invention relates in general to a polarity inversion driving method, and more particularly to a polarity inversion driving method capable of being operated in a number of different inversion schemes.
2. Description of the Related Art
With rapid advance in technology, liquid crystal display has been provided and widely used in various applications. In general, the liquid crystal cells of the liquid crystal display cannot be fixed at a particular voltage, otherwise the liquid crystal cells, once the characteristics are damaged, can no longer be rotated in response to the change in electrical field to form different grey levels. Thus, the voltage must be resumed every period of time to avoid damaging the characteristics of the liquid crystal cells.
Therefore, different polarity inversion driving methods are provided. According to the frame polarity inversion driving method, the polarities of the display data provided to the liquid crystal cells are inverted every one frame. According to the column polarity inversion driving method, the polarities of the display data provided to the liquid crystal cells are inverted every predetermined number of pixel columns. Likewise, according to the row polarity inversion driving method, the polarities of the display data provided to the liquid crystal cells are inverted every predetermined number of pixel rows. According to the dot polarity inversion driving method, the polarities of the display data provided to the liquid crystal cells are inverted every predetermined number of pixels.
Each polarity inversion driving method has its advantages and disadvantages. For example, the column polarity inversion driving method is superior in eliminating the data delay of the data line and reducing power consumption but may trigger vertical flickering and vertical crosstalk and thus deteriorate the image quality. The frame polarity inversion driving method is superior in saving power consumption but the resultant image quality is the worst among these methods. The dot polarity inversion driving method is superior in eliminating crosstalk but is worst in saving power consumption.
Of the aforementioned generally known polarity inversion driving methods, none is superior in all aspects such as display effect (e.g. crosstalk elimination) and power consumption. In addition, the aforementioned polarity inversion driving methods cannot be adjusted in accordance with different design requirements and application conditions (such as device characteristics).
Therefore, how to provide a polarity inversion driving method capable of being flexibly adjusted in accordance with different design requirements and application conditions and achieving optimum performance in various aspects, such as display effect and power consumption, has become an imminent task for the industries.
The invention is directed to a multiple polarity inversion driving method. In comparison to conventional polarity inversion driving method, the multiple polarity inversion driving method of the invention is capable of being operated in a number of different inversion schemes and being flexibly adjusted in accordance with different design requirements and application conditions, hence achieving excellent or ideal performance in terms of display effect (such as elimination of crosstalk), power consumption and other aspects.
According to a first aspect of the present invention, a multiple polarity inversion driving method which can be used for driving a display is provided. The driving method includes providing display data in accordance with an inversion switching time unit as a repeated time unit. The inversion switching time unit has different types of polarity distribution pattern intervals. Additionally, the display data provided to the different types of polarity distribution pattern intervals respectively have different types of polarity distribution patterns on the display.
According to a second aspect of the present invention, a display driver including a timing controller and a data driver is provided. The timing controller instructs the inversion switching time unit having different types of polarity distribution pattern intervals. Display data are provided to a display in accordance with an inversion switching time unit as a repeated time unit. Additionally, the display data provided to different types of polarity distribution pattern intervals by the data driver respectively have different types of polarity distribution patterns on the display.
According to a third aspect of the present invention, a display device is provided. The display device includes a display driver and a display. The display is used for displaying corresponding image frames according to the display data provided by the display driver.
According to a fourth aspect of the present invention, a display device is provided. The display device includes: a display driver and a display. The display driver is used for providing display data in accordance with an inversion switching time unit as a repeated time unit, wherein the inversion switching time unit has a number of different types of polarity distribution pattern intervals. The display is used for displaying corresponding image frames according to the display data provided by the display driver, wherein the display data provided to the different types of polarity distribution pattern intervals respectively have different types of polarity distribution patterns on the display.
According to a fifth aspect of the present invention, a timing controller is provided. The timing controller includes: a timing controller used for instructing an inversion switching time unit. The inversion switching time unit has a number of different types of polarity distribution pattern intervals for driving a data driver, so that the data driver provides display data to a display in accordance with an inversion switching time unit as a repeated time unit. Additionally, the display data provided to different types of polarity distribution pattern intervals by the data driver respectively have different types of polarity distribution patterns on the display.
The above and other aspects of the invention will become better understood with regard to the following detailed description of the preferred but non-limiting embodiment(s). The following description is made with reference to the accompanying drawings.
Referring to
The present embodiment has a unique feature in that the display driver 1 is capable of being operated in a number of different inversion schemes. In other words, the display driver 1 adopts a multiple polarity inversion driving method rather than a single polarity inversion driving method as adopted in generally known technology.
To achieve the above feature, the timing control signal S_ctrl preferably instructs an inversion switching time unit Tu and controls the data driver 12 to provide display data to display 2 in accordance with an inversion switching time unit Tu as a repeated time unit. The number of times of using the inversion switching time unit Tu does not need to be specified or can be specified as a predetermined number of times (such as one or more times). The inversion switching time unit has different types of polarity distribution pattern intervals. In other words, the inversion switching time unit has at least two different types of polarity distribution pattern intervals. Of the different types of polarity distribution pattern intervals, the display data provided by the data driver 12 respectively have different types of polarity distribution patterns on the display 2. Preferably, at least one of the different types of polarity distribution patterns is selected from the following types of polarity distribution patterns, namely, row inversion, column inversion, single dot inversion, multi-dot inversion, multi+multi-dot inversion, and frame inversion.
It is noted that the ratio among the durations of different types of polarity distribution pattern intervals preferably meets a specific requirement. That is, in each polarity inversion switching time, the total number of times of switching each pixel of the display 2 from positive polarity to negative polarity is substantially equal to the total number of times of switching each pixel of the display from negative polarity to positive polarity.
Referring to
In a preferred embodiment (illustrated in
Under such disposition, during the period of 2+N frame cycles Ta_1˜Ta_2+N in the first type of polarity distribution pattern interval Ta, the 2+N first display data Da_1, Da_2, . . . , Da_2+N provided by the data driver 12 have the first type of polarity distribution pattern on the display 2. Besides, during the period of the 1+M frame cycles Tb_1˜Tb_1+M in the second type of polarity distribution pattern interval Tb, the second frame data Db_1, Db_2, . . . , Db_1+M provided by the data driver 12 have the second type of polarity distribution pattern on the display 2. The second type of polarity distribution pattern is not the same with the first type of polarity distribution pattern.
For example, one of the first type and the second type of polarity distribution patterns is such as in accordance with one of row inversion and dot inversion, and the other of the first type and the second type of polarity distribution patterns is such as in accordance with one of column inversion and frame inversion.
In another example, one of the first type and the second type of polarity distribution patterns is, such as, in accordance with one of column inversion and frame inversion, and the other of the first type and the second type of polarity distribution patterns is, such as, in accordance with one of row inversion and dot inversion.
In further another example, one of the first type and the second type of polarity distribution patterns is, such as, n-dot inversion, and the other of the first type and the second type of polarity distribution patterns is, such as, in accordance with one of row inversion, dot inversion, column inversion, frame inversion, n′-dot inversion and m+n″-dot inversion, wherein n, n′, m and n″ are natural numbers larger than 1.
In yet another example, one of the first type and the second type of polarity distribution patterns is, such as, m+n-dot inversion, and the other of the first type and the second type of polarity distribution patterns is, such as, in accordance with one of row inversion, dot inversion, column inversion, frame inversion, n′-dot inversion and m′+n″ dot inversion, wherein m, n, n′, m′ and n″ are natural numbers larger than 1.
In the embodiment illustrated in
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In the aforementioned embodiments disclosed in
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In a preferred embodiment, to meet the aforementioned requirement regarding the number of times of switching, it can be arranged that the ratio between the durations of the third and the fourth type of polarity distribution pattern intervals Tc and Td equals 2+N′:1+M′, wherein N′ and M′ are integers larger than or equal to 0. To put it in greater details, the third type of polarity distribution pattern interval Tc includes 2+N′ frame cycles Tc_1, Tc_2, . . . , Tc_2+N′, and the fourth type of polarity distribution pattern interval Td includes 1+M′ frame cycles Td_1, Td_2, . . . , Td_1 +M′.
Under such disposition, during the period of the 2+N′ frame cycles Tc_1˜Tc_2+N′ of the third type of polarity distribution pattern interval Tc, the 2+N′ third display data Dc_1, Dc_2, . . . , Dc_2+N′ provided by the data driver 12 have the third polarity distribution pattern on the display 2. Besides, during the period of the 1+M′ frame cycles Td_1˜Td_1+M′ of the fourth type of polarity distribution pattern interval Td, the 1+M′ fourth display data Dd_1, Dd_2, . . . , Dd_1+M′ provided by the data driver 12 have the fourth polarity distribution pattern on the display 2, wherein the fourth polarity distribution pattern is different from the third polarity distribution pattern.
Like the first and the second polarity distribution patterns, one of the third and fourth polarity distribution patterns is such as in accordance with one of row inversion and dot inversion, and the other of the third and fourth polarity distribution patterns is such as in accordance with one of column inversion and frame inversion.
In another example, one of the third and the fourth polarity distribution patterns is such as in accordance with one of column inversion and frame inversion, and the third and the fourth polarity distribution patterns the other of is such as in accordance with one of row inversion and dot inversion.
In further another example, one of the third and the fourth polarity distribution patterns is such as in accordance with n-dot inversion, and the other of the third and the fourth polarity distribution patterns is such as in accordance with one of row inversion, dot inversion, column inversion, frame inversion, n′-dot inversion and m+n″-dot inversion, wherein n, n′, m and n″ are natural numbers larger than 1.
In yet another example, one of the third and the fourth polarity distribution patterns is such as in accordance with m+n-dot inversion, and the other of the third and the fourth polarity distribution patterns is such as in accordance with one of row inversion, dot inversion, column inversion, frame inversion, n′-dot inversion and m′+n″ dot inversion, wherein m, n, n′, m′ and n″ are natural numbers larger than 1.
In the embodiment illustrated in
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In another application example, to meet the aforementioned requirement regarding the number of times of switching, wherein N and M N and M are integers satisfying one of the condition that N+M is equal to 0 and the other condition that N+M is equal to any positive even number, and N′ and M′ are integers satisfying one of the condition that N′ and M′ is equal to 0 and the other condition that N′+M′ is equal to any positive even number. According to the above disclosure, the inversion switching time unit Tu′ equivalently includes two segments of inversion switching time unit Tu illustrated in
Referring to
Step (b): during the frame periods Ta_1 ˜Ta_2+N of the first type of polarity distribution pattern interval Ta, a number of first display data Da_1˜Da_2+N corresponding to the first polarity distribution pattern are respectively provided to drive the display 2.
Step (c): during the frame periods Tb_1˜Tb_1+M of the second type of polarity distribution pattern interval Tb, a number of second display data Db_1˜Db_1+M corresponding to the second polarity distribution pattern are respectively provided to drive the display 2.
It is noted that since the inversion switching time unit Tu is used as a repeated time unit, after steps (b) and (c) are sequentially performed, the process returns to step (b). In short, the number of times of using the inversion switching time unit Tu does not need to be specified or can be specified as a predetermined number of times (such as one or more times). Besides, any of the steps (b) and (c) can be used as the starting step or the ending step, and the process does not have to start with step (b) or terminate with step (c). Detailed operations of steps (b) and (c) can be obtained from
Referring to
Step (d): during the frame periods Tc_1˜Tc_2+N′ of the third type of polarity distribution pattern interval Tc, a number of third display data Dc_1˜Dc_2+N′ corresponding to the third polarity distribution pattern are respectively provided to drive the display 2.
Step (e): during the frame period Td_1˜Td_1+M′ of the fourth type of polarity distribution pattern interval Td, a number of fourth display data Dd _1˜Dd_1+M′ corresponding to the fourth polarity distribution pattern are respectively provided to drive the display 2.
It is noted that since the inversion switching time unit Tu is used as a repeated time unit, after steps (b′)˜(e) are sequentially performed, the process returns to step (b′). In short, the number of times of using the inversion switching time unit Tu does not need to be specified or can be specified as a predetermined number of times (such as one or more times). Besides, any of the steps (b′)˜(e) can be used as the starting step or the ending step, and the process does not have to start with step (b′) or terminate with step (e′). Detailed operations of steps (b′)˜(c′) and steps (c)˜(d) can be obtained from
The aforementioned multiple polarity inversion driving method can be implemented in many different ways. For example, the control wave-patterns of a polarity control signal POL of the timing control signals S_ctrl can be used to achieve the desired inversion switching time unit. In general, when the polarity control signal POL is at the first level (such as high signal level), the polarity of the pixel data outputted to the corresponding pixel is negative. To the contrary, when the polarity control signal POL is at the second level (such as low signal level), the polarity of the pixel data outputted to the corresponding pixel is positive.
For example, during the period of each inversion switching time unit, when the polarity distribution pattern of the display 2 is in accordance with dot inversion or column inversion, the timing relationship between the polarity control signal POL and the pixel data loading signal LD is as illustrated in
In another example, during the period of each inversion switching time unit, when the polarity distribution pattern of the display 2 is in accordance with frame inversion, the timing relationship between the polarity control signal POL and the pixel data loading signal LD is as illustrated in
The above two situations are combined below. In order to drive the display, the display driver 1 of the present embodiment has to provide pixel data corresponding to different polarity distribution patterns in the first type and the second type of polarity distribution pattern intervals Ta and Tb respectively, and the timing relationship between the polarity control signal POL and the pixel data loading signal LD is as illustrated in
It is noted that the ratio among the durations of different types of polarity distribution pattern intervals is determined in accordance with the aforementioned number of times of switching as well as design requirements, application conditions and device characteristics. In addition, the types and the number of polarity distribution pattern intervals included in the inversion switching time unit used as a repeated time unit is also determined in according with design requirements, application conditions and device characteristics. For example, the ratio of the durations among different types of polarity distribution pattern intervals can be adjusted based on a single one or more of different factors such as the crosstalk of the display, the target power consumption and so on.
It is noted that in the above embodiments one single polarity distribution pattern interval is used for exemplification. However, in other embodiments, multiple polarity distribution pattern intervals can also be used. In other words, after display data are provided in accordance with the inversion switching time unit as a time unit, subsequent display data are provided in accordance with another one or more inversion switching time units as repeated time unit respectively, and each polarity distribution pattern interval can use a predetermined number of times (such as one or more times).
In comparison to the generally known technology which uses one single type of polarity inversion driving method and is unable to concurrently meet the requirements of display effect and power consumption, the above embodiments adopt different types of polarity inversion driving methods and are capable of flexibly adjusting the ratio of the durations among different types of polarity distribution pattern intervals in accordance with design requirements and application conditions, hence achieving excellent or ideal performance in terms of display effect, power consumption and other aspects.
While the invention has been described by way of example and in terms of the preferred embodiment(s), it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Number | Date | Country | Kind |
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100104339 | Feb 2011 | TW | national |