JP2000250496A - Active matrix type liquid crystal display and driving method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active matrix type liquid crystal display capable of attaining high display quality and reducing power consumption even when a driving method such as performing an interlaced scanning is to be used with respect to pixel electrodes and to provide a driving method therefor. SOLUTION: The driving method of this active matrix type liquid crystal display is the driving method of an active matrix type liquid crystal display which is provided with a display part by plural pixel electrodes (p) which are arranged in a matrix shape and a scan driver interlacingly scanning at least pixel electrodes of one part of these plural pixel electrodes (p) and, in this method, when at least pixel electrodes of one part are to be interlacingly scanned in a first scanning order such as from odd-numbered rows to even- numbered rows in a first frame, they are to be interlacingly scanned in a second scanning order such as from even-numbered rows to odd-numbered rows in a second frame succeeding to the first frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display typified by a TFT (thin film transistor) type liquid crystal display and a method of driving the same, and particularly low power consumption is required. The present invention relates to an active matrix type liquid crystal display used as a display device of a portable device or the like and a driving method thereof.

[0002]

2. Description of the Related Art FIG. 1 is a conceptual diagram of a liquid crystal display. The liquid crystal display includes an active matrix substrate, a counter substrate, and a liquid crystal layer sandwiched therebetween. On the active matrix substrate, as shown in FIG. 1, a display unit 30 including a plurality of pixel electrodes P arranged in a matrix, and a plurality of rows for applying a scanning signal (gate voltage) to the plurality of pixel electrodes P. An electrode (scanning line or gate electrode) G, a plurality of column electrodes (source electrodes) S for applying a data signal (grayscale voltage) to the plurality of pixel electrodes P, a pixel electrode P, a row electrode G, and a column electrode S , A scan driver (gate driver) 32 for driving the row electrodes G, and a data driver (data driver) 34 for driving the column electrodes S. The common electrode 36 is formed on the counter substrate.

[0006] The scan driver 32 is controlled by a control unit 38 and receives a gate voltage from a gate voltage generation circuit 40. The data driver 34 is controlled by the control unit 38 and receives a gray scale voltage from the gray scale voltage generation circuit 42. The common electrode 36 receives the common electrode voltage V
com is driven.

In driving the above-mentioned active matrix type liquid crystal display, generally, the polarity of the voltage applied to the liquid crystal is alternately inverted (this is called "AC driving of liquid crystal"), so that a DC voltage is applied to the liquid crystal. The device is devised so as not to be applied. This is because the liquid crystal has the property that the characteristics are deteriorated when a DC voltage is applied. The most widely used method of AC driving of a liquid crystal in the past is the row inversion method (also called “line inversion method”) shown in FIG.
According to this method, the polarity of the voltage applied to the liquid crystal is inverted for each row (scanning line) and for each frame. When the polarity inversion for each row is added to the polarity inversion for each row, the pixel inversion method (also referred to as “dot inversion”) shown in FIG.
The pixel inversion method is particularly suitable for XGA because of its high display quality.
It is becoming the mainstream for driving large and high-definition displays of more than type.

FIG. 4 shows a simplified pixel P (i, i,
An equivalent circuit corresponding to j) is shown. The capacitance of the pixel is mainly composed of the pixel electrode and the auxiliary electrode (additional electrode). In FIG. 4, the total capacitance is Cp.

FIG. 5 shows the drive timing of each part of the display shown in FIG. 1 and the applied voltage waveform. In FIG. 5, Vsy
n and Hsyn represent a vertical synchronization signal and a horizontal synchronization signal, respectively. When the output VG (j) of the scan driver corresponding to the j-th row becomes high potential, the switch element T (i, j) corresponding to the pixel P (i, j) in the j-th row is turned on, and the pixel P
(I, j) is the output S (i) of the data driver at that time
Will be charged by. When the potential of VG (j) becomes low, the switch element T (i, j) is turned off, and the pixel P (i, j) is turned off.
The charge charged in j) is then stored until T (i, j) is turned on, during which time the liquid crystal filled between the pixel electrode and the common electrode is driven. In FIG. 5,
The number assigned to the horizontal synchronizing signal indicates a horizontal period in which the image signal for the pixel in the row of the number is transmitted. Since the data driver samples and stores the data of the first row and outputs it in the next horizontal period, the scan driver in the corresponding row sets the output to a high potential only in the horizontal period during which data is transmitted. One horizontal period later.

FIG. 6 shows an equivalent circuit of one data line of the liquid crystal display. Cd and Rd respectively indicate the capacitance and resistance of the data line expressed by a lumped constant, Cp indicates the pixel capacitance, and Ron indicates the on-resistance of the switch element. Although the circuit of FIG. 6 becomes a load for one output of the data driver, the pixel capacitance Cp is smaller than the data line capacitance Cd by two to three orders of magnitude, and therefore can be ignored as a load of the driver. Therefore, the load of the driver includes the data line resistance Rd and the data line capacitance Cd.
It is enough to consider d. By the way, the circuit of FIG. 6 exists in a one-to-one correspondence with the output of the data driver. For the entire display, for example, even if it is a VGA type which has a relatively medium resolution at present, if it is color, 640 × 3 = 192
Since there are zero, the load of the data driver as a whole becomes considerably large. In a row inversion method or a pixel inversion method in which the output of the data driver needs to be inverted for each scanning line, the power consumption increases because the capacitance Cd is charged and discharged between positive and negative polarities every output operation. Problem arises.

As one method for preventing the above-mentioned increase in power consumption, Japanese Patent Laid-Open Publication No. H8-32067 proposes interlaced scanning. "Interlaced scanning" means that all odd-numbered (or even-numbered) pixel electrodes are scanned first,
Next, the remaining even (or odd) rows of pixel electrodes are scanned. In this method, the rows of pixels having the same polarity are sequentially scanned, so that the increase in the power consumption can be suppressed. When scanning of one frame (that is, scanning of both odd and even rows) is completed, a state similar to that in FIG. 2 or FIG. 3 is obtained.

[0009]

However, although the power consumption is reduced by the above-described interlaced scanning, a new problem is that a slight horizontal stripe is generated every other row due to a slight difference in gradation between an odd row and an even row. May occur. In addition, flicker (flicker) that cannot be ignored sometimes, and image quality deterioration of a moving image having large motion are also observed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the image quality such as flicker or the adjacent line gap even when a driving method of interlaced scanning of a pixel electrode is used. It is an object of the present invention to provide an active matrix type liquid crystal display capable of achieving high display quality and low power consumption without generating horizontal stripes due to a difference in gray scale of the above and a driving method thereof.

[0011]

A method of driving an active matrix type liquid crystal display according to the present invention comprises a display section including a plurality of pixel electrodes arranged in a matrix and at least a part of the plurality of pixel electrodes. And a scan driver for interlaced scanning of the active matrix type liquid crystal display, wherein at least some of the pixel electrodes are arranged in a first scanning order from odd rows to even rows in a first frame. When the interlaced scanning is performed in the second frame following the first frame, the interlaced scanning is performed in the second scanning order of even-numbered rows to odd-numbered rows,
Thereby, the above object is achieved.

In another driving method of an active matrix type liquid crystal display according to the present invention, a display section including a plurality of pixel electrodes arranged in a matrix and at least a part of the plurality of pixel electrodes are skipped and scanned. A driving unit for driving the active matrix type liquid crystal display device, wherein at least some of the pixel electrodes are divided into a plurality of areas in a column direction, and the plurality of areas are sequentially skipped. Performed, and in one of the plurality of areas, the pixel electrodes are interlacedly scanned in a first scanning order from an odd row to an even row in a first frame, and in a second frame subsequent to the first frame, Interlaced scanning is performed in a second scanning order from even rows to odd rows,
Thereby, the above object is achieved.

In one embodiment, preferably, the second
The interlaced scanning is performed in the second scanning order in the third frame subsequent to the third frame, and the interlaced scanning is performed in the first scanning order in the fourth frame subsequent to the third frame.

An active matrix type liquid crystal display according to the present invention comprises: a display section including a plurality of pixel electrodes arranged in a matrix; a scan driver for skipping at least a part of the plurality of pixel electrodes; Wherein the at least some pixel electrodes are interlacedly scanned in a first scanning order from odd-numbered rows to even-numbered rows in the first frame. In the second frame subsequent to the above, interlaced scanning is performed in a second scanning order from even-numbered rows to odd-numbered rows, thereby achieving the above object.

Another active matrix type liquid crystal display according to the present invention is a display unit including a plurality of pixel electrodes arranged in a matrix, and a scan driver for skipping and scanning at least a part of the plurality of pixel electrodes. Wherein the at least some of the pixel electrodes are divided into a plurality of sections in the column direction, and the plurality of sections are sequentially interlaced and scanned, and In one of the areas, the pixel electrodes are arranged in odd-numbered rows to even-numbered rows in the first frame.
, The interlaced scanning is performed in the second frame following the first frame in the second scanning order of even rows to odd rows, thereby achieving the above object.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Generation of Horizontal Stripes in Every Other Row> First, the cause of the occurrence of horizontal stripes in every other row due to interlaced scanning will be described. In the following description, the polarity of the pixels in the same row will be described in a row inversion mode in which the polarity is the same. However, in the pixel inversion mode, only the polarity is inverted for each column, and the description can be applied as it is. The description of the case of the inversion mode is omitted. Note that the “row inversion mode” here means that the screen polarity is in the state of FIG. 2 when driving of one frame is completed as described above, and the “pixel inversion mode” As described above, this indicates a screen in which the polarity of the screen at the time when driving of one frame is completed is in the state of FIG.

FIGS. 7A to 7D show the state transition of the voltage polarity when the pixel electrode is skipped and scanned. FIG. 7 (a)
Indicates a state immediately before a new frame starts. At this time, the voltage polarity of each pixel is in a row inversion state. By scanning only the odd-numbered rows from here, the voltage polarities of the pixels in the odd-numbered rows are inverted, and the state shifts to the state shown in FIG. Next, by scanning the even-numbered rows, the voltage polarities of the pixels in the even-numbered rows are inverted, and the state shifts to the state shown in FIG. The state in FIG. 7C is a state in which scanning of one frame is completed. In the next frame, the state is changed to the state shown in FIG. 7A through the state shown in FIG. 7D similarly (however, the polarity is reversed).

FIG. 8 shows four adjacent columns (ie, four columns).
1 shows pixel electrodes P (over a row) (TFT switch elements are omitted). A scanning line (gate line) G exists between the pixel electrodes P, and the sides in the scanning line direction are parallel, so that a coupling capacitance Cpp exists between adjacent pixel electrodes. The charge is held in the coupling capacitance Cpp by the voltage difference V between the two adjacent pixel electrodes, and the magnitude of the charge is
It is a function of the voltage difference V, which is 0 when V = 0, and a monotonically increasing function with respect to V (where V ≧ 0). In addition,
Since the dielectric constant of the liquid crystal changes depending on the alignment state, the coupling capacitance Cpp itself is also a function of the voltage difference V.

FIGS. 9 (a) and 9 (b) show the case where charge is generated in the coupling capacitance Cpp and the case where no charge is generated in the coupling capacitance Cpp (that is, all four pixel electrodes shown in FIG. 8 are set to the same potential). 2) shows an equivalent circuit of four pixel electrodes. When no charge is generated in the coupling capacitance Cpp,
In order to make the equivalent circuit easier to see, the relevant portion of the coupling capacitance Cpp is omitted from FIG. 9B (the same applies hereinafter). It is assumed that the same data is written on the entire screen. Note that “writing data” means charging a pixel electrode with a voltage corresponding to data (the same applies hereinafter).

When transitioning from the state of FIG. 7A to the state of FIG. 7B and transitioning from the state of FIG. 7C to the state of FIG. Transitions from the appearing state to the disappearing state. For simplicity, the effect between pixels in two adjacent rows will be described with reference to FIGS. When the pixels in the odd rows are written while the switch elements A in the even rows are open, the movement state of the electric charges is changed from FIG. 10A to FIG. 10B or FIG.
The transition from (c) to FIG. 10 (d) is made. Since the switch element A in the even-numbered row remains open, the electric charge of −q or + q captured by the capacitance Cpp moves to the pixel electrode in the even-numbered row due to the disappearance of the voltage difference between both ends of the capacitance Cpp. The charge of the pixel electrode increases to-(Q + q) or (Q + q). That is, writing data to the pixels in one row (odd-numbered row) works to increase the voltage of the pixels in the adjacent row (even-numbered row). Strictly speaking, a slight difference in potential caused here causes a small charge to remain between the capacitors A and B in the capacitor Cpp, but it is negligible because it is extremely small with respect to the original charge q. Note that “deeper voltage” means that the potential difference between the pixel electrode and the common electrode becomes larger (the same applies hereinafter).

In FIGS. 10A and 10C, the electric charges of the pixels in the odd-numbered rows are Qq and-(Qq), respectively, as will be apparent from the following description with reference to FIG. 7D from the state of FIG. 7D to the state of FIG. 7A or the state of FIG.
This is a result affected by the transition to the state (c). Since the adjacent row is an even-numbered row in the above case, a voltage is applied to the even-numbered row deeper than the original gradation.

With the same consideration, the state shown in FIG.
FIG. 7A to the state of FIG. 7C or from the state of FIG.
In the case of transition to the state of FIG. 11, the equivalent circuit changes from the state of FIG. 11B to the state of FIG. 11C or FIG.
The state transits to the state of (a). The appearance of the voltage difference between adjacent rows causes the electric charge of the pixel electrode to move to the capacitance Cpp, thereby acting to lower the voltage for the pixels of the adjacent row. “The voltage becomes shallow” means that the potential difference between the pixel electrode and the common electrode becomes small (the same applies hereinafter). Since the adjacent row is an odd row in this case, the voltage of the odd row becomes shallower than the original gradation.

As described above, when a potential having the same polarity as the polarity of the voltage of an electrode is written to an electrode adjacent to a certain electrode, the voltage of the electrode becomes deep, while when a voltage of the opposite polarity is written, That is, the voltage of the electrode becomes shallower. For this reason, in the case of a normally black display, the odd-numbered rows are thinner than the original gradations and the even-numbered rows are darker, so that a slight gradation difference occurs between the even-numbered rows and the odd-numbered rows. It will be observed as thin horizontal stripes every other line.

FIG. 12 shows the driving waveforms when the display includes eight rows of pixel electrodes and scanning lines. In addition,
For the sake of simplicity, it is assumed that the display has eight scanning lines unless otherwise specified. Although the actual number of scanning lines of the display is much larger, for example, 726, the driving principle is exactly the same. In FIG. 12, VP (i, 3) and VP (i, 4) represent the potentials of the pixel electrodes on the third and fourth rows, respectively. Show.

As described above, an electrode adjacent to a certain electrode is:
When writing a potential having the same polarity as the polarity of the voltage of the electrode, the voltage of the electrode increases, while when writing a voltage of the opposite polarity, the voltage of the electrode decreases. This is reflected in the waveform shown in FIG. That is, VP (i, 3), which is an odd row, fluctuates so that the voltage becomes shallower in successive frames, and PV (i, 4), which is an even row,
Conversely, the voltage fluctuates so as to increase.

There are other factors, such as a pull-in voltage when the gate is turned off, as factors that cause the potential of the pixel to fluctuate. These factors are not directly related to the present invention and are shown in order to avoid complication. No (same below).
In addition, the fluctuation of the potential is extremely exaggerated for visual recognition. Although the actual level of the potential fluctuation depends on the characteristics of the display and cannot be unconditionally determined, it is, for example, about 1% of the pixel electrode potential with respect to the common electrode.

In the above description, a case was described in which data was first written to pixels in odd-numbered rows, and then data was written to pixels in even-numbered rows. However, even when data was written to even-numbered rows first and odd-numbered rows were written later. Since the cause of the problem that occurs is the same, the description is omitted.

According to the present invention, an image display based on the coupling capacitance between adjacent pixels on the same column as described above can be performed even when all or a part of the screen is skipped in order to reduce power consumption. This is to prevent deterioration and realize high-quality display without horizontal stripes.

<Basic Concept of the Present Invention> As discussed above, when all or part of the screen is interlacedly scanned in a certain field, the voltage polarity of the pixels in the adjacent rows changes from the different state to the same state. When it changes
The voltage of the pixel written in the previous field changes to be deeper. When the voltage polarity of the pixels in the adjacent row changes from the same state to a different state, the voltage of the pixel written in the previous field changes so as to be shallow.

In consideration of this situation, in order to eliminate the horizontal stripes in every other row, the present invention makes the voltage of the pixel of one row shallow in one frame and increases in the next frame. To do. This allows
The change in the voltage of the pixel is canceled in successive frames, and a uniform voltage is applied to the pixel as an effective value. More specifically, in a portion where the interlaced scanning is performed, in a certain frame, when scanning is performed in the first scanning order in which the scanning of the odd-numbered pixel electrodes is performed after the scanning of the odd-numbered pixel electrodes, the following scanning is performed. In the frame, scanning is performed in a second scanning order in which scanning of odd-numbered pixel electrodes is performed after scanning of even-numbered pixel electrodes in the opposite direction to the first scanning order. That is, the first scanning order and the second scanning order are alternated for each frame, thereby eliminating horizontal stripes every other row.

(First Embodiment) Hereinafter, a first embodiment of a method of driving an active matrix type liquid crystal display according to the present invention will be described in detail. The active matrix type liquid crystal display according to the present invention has a configuration basically similar to the configuration shown in FIG. 1, and a description thereof will be omitted.

The driving method of the active matrix type liquid crystal display of this embodiment will be described with reference to FIG. FIG.
FIG. 2 is a schematic diagram of a display unit 30 (FIG. 1) in which pixels in a row are shown as one line. This figure shows the order of scanning over two frames (frame (a) and frame (b)). The numbers on the left end are the numbers of the pixel rows counted in order from the top of the screen, and the numbers shown in circles indicate the order of scanning.

First, in the frame (a), the odd rows of the first, third, fifth and seventh rows are scanned (first field of the first frame), and then the even rows of the second, fourth, sixth and eighth rows are scanned. Scan (first field, second field). Conversely, in the next frame (b), the even-numbered rows of the second, fourth, sixth and eighth rows are scanned first (the first field of the second frame), and then the first, second and third rows are scanned.
Scan odd rows 3, 5, and 7 (second frame 2
field).

FIGS. 14A to 14D show the state transition of the polarity of the pixel in the above scanning. In the first field of the first frame, the first, third, fifth and seventh rows change from positive to negative (transition from the state (a) to the state (b)). Therefore, the pixels in the adjacent rows (second, fourth, sixth and eighth rows) are the first,
Since the transition is made from the different polarity to the same potential of the same polarity for the pixels in rows 3, 5, and 7, the pixel voltages in rows 2, 4, 6, and 8 written in the previous field become deeper. (Actually, the potential that has become shallow returns to its original state).

In the second field of the first frame, the second,
The polarities of the pixels in rows 4, 6, and 8 change from negative to positive (transition from state (b) to state (c)). Therefore,
Pixels in adjacent rows (first, third, fifth and seventh rows) are second, fourth,
Since the transition from the same potential of the same polarity to a different polarity is performed for the pixels in rows 6 and 8, the pixel voltages in the first, third, fifth and seventh rows written in the previous field become shallower.

In the first field of the second frame, the second,
The polarities of the pixels in rows 4, 6, and 8 change from positive to negative (transition from the state (c) to the state (d)). Therefore,
Pixels in adjacent rows (first, third, fifth and seventh rows) are second, fourth,
Since the transition is made from the different polarity to the same potential of the same polarity for the pixels in rows 6 and 8, the potential becomes deeper (actually the shallow potential returns to the original).

In the second field of the second frame, the first,
The polarities of the pixels in rows 3, 5, and 7 change from negative to positive (transition from the state (d) to the state (a)). Therefore,
The pixels in the second, fourth, sixth and eighth rows are first, third, fifth and seventh
Since the transition from the same polarity to a different polarity is performed for the pixels in the row, the potential becomes shallow.

FIG. 15 shows a driving waveform of the above scanning. Both the odd-numbered pixel P (i, 3) and the even-numbered pixel P (i, 4) have the potentials (VP (i, 3) and V
Since P (i, 4)) varies so as to be shallow, the influence on the gradation in the odd-numbered / even-numbered rows is the same, and horizontal stripes do not occur. However, in the present embodiment, since the drive times of the positive polarity and the negative polarity are different, a DC is applied slightly as an average value. But that is not immediately a problem at the practical level. Even if a direct current as an average value is applied, a slight voltage does not lead to irreversible destruction of the liquid crystal. This is because, for example, a problem such as an afterimage is likely to occur, but there is no problem if there is no problem from a practical level. In this sense, the present embodiment has a sufficient level of practicality depending on the intended use of the display.

In the above description, the case where all the screens display the same gradation is described for easy understanding. When the gradation of the pixels in the adjacent rows is different, the charge always remains in the coupling capacitance Cpp. However, the movement of the charge is caused by the same mechanism, and the difference from the original gradation is slightly the same. It is. Also in the following description, a case where all screens display the same gradation will be described.

(Second Embodiment) A second embodiment of the method for driving an active matrix type liquid crystal display according to the present invention will be described below. In the present embodiment, the scanning order of the first frame and the second frame is the same as that of the first embodiment, and the third frame and the fourth frame are the scanning order opposite to that of the first frame and the second frame. To That is, in the third frame, the even-numbered rows are scanned first and the odd-numbered rows are scanned later.
In the frame, odd rows are scanned first and even rows are scanned later.

FIGS. 16A to 16D show the scanning order of four consecutive frames as described above. FIG. 17 shows the driving waveform. As shown in FIG. 17, T ₁ (+) and T ₂ of the voltage VP (i, 3) of the pixel P (i, 3) in the third row.
(+), T ₁ (−), and T ₂ (−) are the T P of the voltage VP (i, 4) of the pixel P (i, 4) in the fourth row, respectively.
_The waveforms are inverted with respect to the ₁ (+), T ₂ (+), T ₁ (−), and T ₂ (−) portions and the common electrode. Therefore, the effective values (alternating current) are almost the same, no difference in gradation occurs, and no horizontal stripes occur.

The present embodiment is superior to the first embodiment in that the pixels in the odd-numbered rows and the pixels in the even-numbered rows have a positive polarity time and a negative polarity time, with four frames as one cycle. Are the same. Pixels P (i, 3) and P (i, 4) both have the time obtained by adding T ₁ (+) and T ₂ (+) to the time obtained by adding T ₁ (−) and T ₂ (−). It is because they are equal. Therefore, it is possible to prevent the occurrence of horizontal stripes without sacrificing the AC driving of the liquid crystal for preventing the application of the DC voltage as an average value. If the time of one frame is 1/60 second, the period of four frames is 1/15 second. However, since the voltage difference in question here is very small, this causes flickering. I will not do it.

(Third Embodiment) A third embodiment of the method for driving an active matrix type liquid crystal display according to the present invention will be described below.

FIG. 18 shows drive waveforms when the first embodiment is applied to a display including 18 rows of pixels. In FIG. 18, the drive waveforms of the pixels in the ninth and subsequent rows are omitted. It should be noted that the numbers assigned to the Hsyn waveform are numbers assigned sequentially from the horizontal period corresponding to the period in which scanning is started (the meaning is different from the number assigned to the Hsyn waveform in FIG. 5). . The problem of the driving in FIG. 18 is that the imbalance between the time during which the positive voltage is applied to the pixel and the time during which the negative voltage is applied to the pixel is greater than in the case of the driving in FIG. This imbalance increases as the number of rows increases.

The third embodiment according to the present invention is to solve this problem. FIGS. 19 (a) and (b)
Indicates the scanning order of pixels over two frames in the present embodiment. In the present embodiment, the pixels of the display unit are set to 2
It is divided into two areas (a first area and a second area), and for each area, the jump scanning is completed in the order of the numbers surrounded by ○.

FIG. 20 shows a driving waveform of the above scanning.
Note that, similarly to FIG. 18, the drive waveforms of the pixels in the ninth and subsequent rows are omitted. As is apparent from the figure, since the interlaced scanning is completed in each area, the imbalance in the time required to apply the positive and negative voltages of each pixel is smaller than in the case of FIG. Even when the number of rows of pixels is further increased, an increase in the number of areas can suppress an increase in the imbalance between positive and negative. For example, in the case where the number of rows of pixels is 480, the number of pixels may be divided into 60 sections every 8 pixels. Of course, the number of lines included in one area is not limited to eight, and can be determined to any number.

The method of dividing the display section into a plurality of sections in the column direction and completing the interlaced scanning for each section as described above is disclosed in Japanese Patent Application No. Hei.
This is described in more detail in the paragraph 0-161199. With this method, power consumption can be reliably reduced, and flickering and image quality deterioration of a moving image having large motion can be suppressed.

(Fourth Embodiment) FIGS. 21 (a) to 21 (d)
9 shows a pixel scanning order according to the fourth embodiment of the active matrix type liquid crystal display driving method of the present invention. In this embodiment,
The third embodiment (FIG. 19) is different from the second embodiment (FIG. 1).
This is the case where the concept of 6) is added.

According to the present embodiment, the imbalance in the time during which the positive and negative voltages of each pixel are applied is suppressed (the effect of the third embodiment), and the time during which the pixels in the odd-numbered rows and the pixels in the even-numbered rows have the positive polarity is obtained. The application of the DC voltage as an average value is prevented by making the time of the negative polarity the same as the above (effect of the second embodiment).
However, the occurrence of horizontal stripes can be prevented.

(Fifth Embodiment) FIGS. 22A and 22B show the scanning order of pixels according to a fifth embodiment of the driving method of the active matrix type liquid crystal display of the present invention.

This embodiment is a modification of the embodiment of FIG. 19 (third embodiment).
And the order of the scans is reversed, as shown in FIGS. More specifically, when performing interlaced scanning in a first scanning order from odd rows to even rows in the first area, interlacing scanning in a second scanning order from even rows to odd rows in the second area. I do. Also, needless to say,
When performing interlaced scanning in the second scanning order in the first area, interlaced scanning is performed in the first scanning order in the second area.

As described above, in the present embodiment, even if the scanning order of each area is set independently, the essence of the present invention is not deviated, and the above-described effects can be obtained.

In all of the above embodiments, it goes without saying that the polarity of the pixel potential may be reversed in each frame. Also, although not directly related to the essence of the present invention and not specified in the above embodiments, the data driver outputs data to the pixel electrodes in response to scanning of the pixel electrodes in each row. It goes without saying that it is controlled.

[0054]

In the driving method for performing the interlaced scanning on the display section, the pixel electrodes are scanned over the odd-numbered (or even-numbered) pixel electrodes in a certain frame and then over the even-numbered (or odd-numbered) pixel electrodes. In such a case, in the next frame, the pixel electrodes on the even rows (or the odd rows) are scanned first, and then the pixel electrodes on the odd rows (or the even rows) are scanned. As a result, power consumption is reduced, and at the same time, occurrence of horizontal stripes every other row can be prevented.

In the case where the display section is divided into a plurality of sections in the column direction and the pixel electrodes are interlacedly scanned in one section in the first scanning order in the first frame, the display section following the first frame may be used. In frame 2, interlaced scanning is performed in the second scanning order. As a result, it is possible to suppress flicker (flicker) and image quality deterioration of a moving image having large motion.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a liquid crystal display.

FIG. 2 is a diagram showing a polarity distribution and transition of a pixel voltage in a row inversion method;

FIG. 3 is a diagram showing a polarity distribution and transition of a pixel voltage in a pixel inversion method;

FIG. 4 is a simplified equivalent circuit diagram of a TFT and a pixel.

FIG. 5 is a diagram showing a drive timing of a TFT liquid crystal display and a waveform of a pixel voltage.

FIG. 6 is an equivalent circuit diagram of a data line.

FIGS. 7A to 7D are diagrams showing the state transition of the polarity of the pixel voltage when performing interlaced scanning.

FIG. 8 is a diagram showing continuous pixel electrodes on the same column.

FIGS. 9A and 9B are equivalent circuit diagrams of continuous pixel electrodes on the same column.

10A to 10D are diagrams showing a state change of an equivalent circuit when pixels in odd rows are charged.

FIGS. 11A to 11D are diagrams showing a state change of an equivalent circuit when pixels in an even-numbered row are charged.

FIG. 12 is a diagram showing drive waveforms of a display device when display quality is deteriorated.

FIGS. 13A and 13B are diagrams showing a scanning order of pixel electrodes according to the first embodiment of the present invention.

14 (a) to (d) are diagrams showing the state transition of the polarity of the pixel voltage in the scan of FIG.

FIG. 15 is a diagram showing a driving waveform of the scanning in FIG. 13;

FIGS. 16A to 16D are diagrams showing the scanning order of pixel electrodes according to the second embodiment of the present invention.

FIG. 17 is a diagram showing driving waveforms of the scanning in FIG. 16;

FIG. 18 is a diagram showing a driving waveform of scanning according to the first embodiment of the present invention when the number of rows of pixels is large.

FIGS. 19A and 19B are diagrams showing a scanning order of pixel electrodes according to the third embodiment of the present invention.

FIG. 20 is a diagram showing a driving waveform of the scanning in FIG. 19;

FIGS. 21A to 21D are diagrams showing a scanning order of pixel electrodes according to a fourth embodiment of the present invention.

FIGS. 22A and 22B are diagrams showing a scanning order of pixel electrodes according to a fifth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 30 display unit 32 scan driver (gate driver) 34 data driver (data driver) 36 common electrode 38 control unit 40 gate voltage generation circuit 42 gradation voltage generation circuit 44 common electrode drive circuit

Continuing from the front page (72) Inventor Yasukun Yamane 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka F-term (reference) 2H093 NA16 NA34 NA45 NC34 ND10 ND15 ND39 5C006 AA16 AC29 AF44 BB14 BB16 BF43 FA22 FA23 FA47 5C080 AA10 BB05 DD05 DD06 DD26 EE29 FF11 JJ02 JJ03 JJ04

Claims (6)

[Claims] 1. An active matrix type liquid crystal display comprising: a display unit including a plurality of pixel electrodes arranged in a matrix; and a scan driver for skipping and scanning at least a part of the plurality of pixel electrodes. The method according to claim 1, wherein the at least some pixel electrodes are interlacedly scanned in a first scanning order from an odd-numbered row to an even-numbered row in a first frame. In the method of driving an active matrix type liquid crystal display, interlaced scanning is performed in a second scanning order from even rows to odd rows. 2. In a third frame following the second frame, interlaced scanning is performed in the second scanning order, and in a fourth frame following the third frame, interlaced scanning is performed in the first scanning order. The method of driving an active matrix type liquid crystal display according to claim 1, wherein scanning is performed. 3. An active matrix type liquid crystal display comprising: a display unit including a plurality of pixel electrodes arranged in a matrix; and a scan driver for skipping and scanning at least a part of the plurality of pixel electrodes. The at least some of the pixel electrodes are divided into a plurality of areas in the column direction, and the plurality of areas are sequentially scanned in an interlaced manner, and the pixel electrodes are arranged in one of the plurality of areas. When the interlaced scanning is performed in the first frame in the first scanning order of odd rows to even rows, in the second frame following the first frame, the interlaced scanning is performed in the second scanning order of even rows to odd rows. Method for driving an active matrix type liquid crystal display. 4. In a third frame following the second frame, interlaced scanning is performed in the second scanning order, and in a fourth frame following the third frame, interlaced scanning is performed in the first scanning order. 4. The driving method of an active matrix type liquid crystal display according to claim 3, wherein scanning is performed. 5. An active matrix type liquid crystal display comprising: a display unit including a plurality of pixel electrodes arranged in a matrix; and a scan driver for skipping and scanning at least a part of the plurality of pixel electrodes. Wherein at least some of the pixel electrodes are skipped in a first scanning order from an odd row to an even row in a first frame, and an even row in a second frame following the first frame. An active matrix type liquid crystal display, which is interlacedly scanned in a second scanning order of odd rows. 6. An active matrix type liquid crystal display, comprising: a display section including a plurality of pixel electrodes arranged in a matrix; and a scan driver for skipping and scanning at least a part of the plurality of pixel electrodes. The at least some of the pixel electrodes are divided into a plurality of sections in the column direction, and the plurality of sections are sequentially interlaced, and in one of the plurality of sections, the pixel electrode is a first electrode. When the interlaced scanning is performed in the first scanning order of the odd rows to the even rows in the first frame, the interlaced scanning is performed in the second scanning order of the even rows to the odd rows in the second frame following the first frame. Active matrix liquid crystal display.