WO1994000791A1

WO1994000791A1 - Two-terminal type active matrix liquid crystal display device and driving method thereof

Info

Publication number: WO1994000791A1
Application number: PCT/JP1993/000832
Authority: WO
Inventors: Seigo Togashi
Original assignee: Citizen Watch Co., Ltd.
Priority date: 1992-06-19
Filing date: 1993-06-21
Publication date: 1994-01-06
Also published as: JP3167135B2; EP0600096A4; DE69323276T2; EP0600096B1; EP0600096A1; DE69323276D1

Abstract

This invention is directed to provide a driving method capable of reducing the sticking and after-image of a picture resulting from the change of characteristics of a switching device due to a current in a two-terminal type active matrix liquid crystal display device. The liquid crystal display device includes a plurality of data lines and scanning lines, and liquid crystal pixels so disposed as to correspond to points of intersections between the data lines and the scanning lines. The liquid crystal pixel has at least one two-terminal type switching device, and is driven by a scanning signal applied to the scanning line and a data signal applied to the data line. Here, a period (27, 28, 32, 33) in which a current is supplied through the switching device is disposed before a selection period (26, 31) of the scanning signal Ζ(n). Further, a retention period is disposed after the selection period.

Description

Specification

TECHNICAL FIELD The present invention relates to a two-terminal active matrix liquid crystal display device and a method of driving the same.

Liquid crystal displays are widely applied as low power flat panel displays. Among them, the active matrix method in which a switching element is built in each pixel and driven is being used as a large-capacity, high-quality display element in televisions, information terminals, and the like. As the switching element, a non-linear resistance element such as a three-terminal TFT (thin film transistor) and a two-terminal diode ゃ MIM is used. The two-terminal type is easier to manufacture than the three-terminal type, and is expected in the future. The present invention relates to a two-terminal type active matrix liquid crystal display device using a two-terminal type switching element and a driving method thereof. Background art

Figure 3 shows a block diagram of an active matrix liquid crystal display using a two-terminal switching element. The matrix display panel 3 includes matrix lines D1, D2,..., DM and scanning lines S1, S2,..., SN arranged in a matrix. A liquid crystal pixel 1 and a two-terminal switching element 2 are provided corresponding to the intersection. The data signal is supplied from the data line driver circuit 4 to the data line, and the scanning signal is supplied from the scanning line driver circuit 5 to the scanning line. A control circuit for processing a clock and an image signal 7 and a power supply circuit 6 are connected to the data line driver circuit 4 and the scanning line driver circuit 5. As a two-terminal switching element, an MIM having a metal-insulator-metal (conductor) structure and a nonlinear current-voltage characteristic is often used. The typical structure of M IM In some cases, the lower electrode is made of Ta, the insulating film is made of an anodic oxide film (TaOx), and the upper electrode is made of IT0 (transparent conductor). It can be manufactured with two patterns (masks).

FIG. 2 shows a scanning signal type and a data signal type in a conventional method of driving a two-terminal type active matrix liquid crystal display device such as a diode or a MIM (Japanese Patent Laid-Open No. 59-57288). 0 (η) and 0 (η + 1) are the scanning signals applied to the n-th and n + 1-th scanning lines, respectively.The scanning signal is a selection period for writing the electric charges accumulated in the liquid crystal display pixels and the electric charges. Has a retention period for retaining In general, a liquid crystal display pixel needs to be driven by a voltage of both polarities. Therefore, during the selection period, a positive potential is applied to the liquid crystal display pixel and the two-terminal switching element having a selection potential Val and a positive voltage is applied to the liquid crystal display pixel.選択 (η), Η '(η + 1) and a second selection period in which a negative voltage is applied with a selection potential Va2 and a negative charge is applied to the liquid crystal display pixels. H ′ (n). H (n + 1). The other non-selection periods have the holding potentials Vb 1 and Vb 2 and are the holding periods.

The data signal D (m) applied to the m-th data line takes a potential between the data electricity Vdl and Vd2. Either amplitude modulation or pulse width modulation is used for gradation display, and FIG. 2 shows the latter example. Numeral 12 is a reference potential. In this figure, even if it fluctuates in the whole system drawn at a constant potential, it fluctuates in many cases depending on the power supply voltage of the driver circuit because it is equivalent in principle. In the figure, Val and Va2 and Vbl and Vb2 are shown symmetrically with respect to the reference potential. However, if the characteristics of the two-terminal switching element are not symmetric, they may be asymmetric. In this example, the selection potentials of the nth and n + 1st consecutive selection periods H (11), 11 (11 + 1) and ^ 1 '(n), H' (n + 1) are inverted. In contrast to the example of line-by-line inversion, Responding, however, is often the case of field-by-field inversion.

Next, problems of the conventional driving method will be described with reference to FIGS. 4 (A) to 4 (D). Active Matrix Using Two-Terminal Switching Devices The biggest problem with liquid crystal display devices, especially when MIM is used as the switching device, is image sticking and afterimage phenomena. Fig. 4 (A) shows the ideal transmittance change when displaying white, halftone, black, and halftone in the case of normally white display, and Fig. 4 (B) is the same. It shows the change in the actual transmittance with respect to the display. The transmittance change waveform of FIG. 4 (B) does not match the waveform of FIG. 4 (A). When changing from white to halftone, an image that is slightly darker than halftone is burned in for a certain period of time as indicated by 17; conversely, when changing from black to halftone, an image that is slightly brighter than halftone is printed for a certain period of time such as 18. This is because the threshold voltage Vth of the switching element changes. This change depends on the amount of current flowing through the switching element, and the threshold voltage Vth tends to increase when a state with a large amount of current continues to some extent, and conversely, Vth tends to decrease with a small amount of current. The amount of current flowing through the switching element depends on the voltage applied during the selection period, and the applied voltage depends on the degree of gray scale to be displayed. In the case of normally white, the darker the darker, the larger the current, and the amount of current flowing through the switching element when the gradation changes as shown in Fig. 4 (A) changes as shown in Fig. 4 (C). Therefore, the threshold voltage changes as shown in Fig. 4 (D), and afterimages and image sticking occur for a certain period from the point of time when the gradation changes to a stable state. The threshold voltage Vth changes even in white or black, and burn-in occurs in principle in white or black. However, in the white or white state, there is little change in the transmittance with respect to the applied voltage, and the image is most noticeable in halftone. <2-terminal type using a switching element whose element characteristics change depending on the amount of current flowing as described above In an active matrix liquid crystal display device, image burn-in and afterimage caused by the change in characteristics become a problem. Obedience In the conventional driving method, the amount of current flowing through the switching element differs depending on the gray scale displayed on the liquid crystal pixels, and this phenomenon cannot be eliminated. An object of the present invention is to provide a driving method capable of improving image sticking and an afterimage phenomenon by increasing the amount of current flowing through the switching element as compared with the conventional example. Disclosure of the invention

In order to achieve the above object, the method for driving a two-terminal active matrix liquid crystal display device of the present invention has a selection period, a current application period preceding the selection period, and a holding period following the selection period as a scanning signal. It is characterized by using signals, and its basic technical configuration includes a plurality of data lines and scanning lines, and liquid crystal pixels provided corresponding to intersections of the data lines and scanning lines. The liquid crystal pixel has at least one two-terminal switching element, and is a two-terminal active mask in which the liquid crystal pixel is driven by a scanning signal applied to a scanning line and a data signal applied to a data line. In the driving method of the liquid crystal display device, the scanning signal is a signal for applying a current to the switching element prior to the selection period for writing the electric charge stored in the liquid crystal pixel. It is configured two-terminal type active Conclusions Li hex liquid crystal display device to have a retention period following the application interphase and the selection period.

Still another technical configuration of the present invention is a driving method for driving the above-described liquid crystal display device as described above. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows driving waveforms in one embodiment of a driving method of a two-terminal type active matrix liquid crystal display device of the present invention.

Figure 2 shows the drive of a conventional two-terminal active matrix liquid crystal display. It is a drive waveform in the method.

FIG. 3 is a block diagram of an active matrix liquid crystal display device using a typical two-terminal switching element.

FIG. 4 is an explanatory diagram of a problem of the conventional driving method.

FIG. 5 is an explanatory diagram showing the effect of the driving method of the present invention.

FIG. 6 shows a scanning signal waveform in another embodiment of the driving method of the present invention. FIG. 7 shows a driving waveform in another embodiment of the driving method of the present invention. FIG. 8 is a block diagram showing a configuration example of the liquid crystal display device of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 8 is a block diagram showing a configuration example of a two-terminal active matrix liquid crystal display device according to the present invention. The basic structure is substantially the same as that of the conventional liquid crystal display device shown in FIG. Since members having the same functions are denoted by the same reference numerals, detailed description thereof will be abbreviated here.

The difference between the two-terminal type active matrix liquid crystal display device according to the present invention and the related art two-terminal type active matrix liquid crystal display device shown in FIG. In addition, prior to the selection period, the control circuit 6 further includes a current application period setting means 61 for setting a current application period for applying a current to the two-terminal switching element 2; Polarity setting means 62 for determining the polarity of the current applied to the two-terminal switching element 2 during the application period, voltage setting means 63 for determining the voltage of the current applied to the two-terminal switching element 2 And application of current applied to the two-terminal switching element 2. An application frequency setting means 64 for determining the frequency is provided, and each of the means is configured to be controlled by an appropriate control means.

That is, FIG. 8 shows a configuration example of a liquid crystal display device according to the present invention. The configuration includes, for example, a plurality of data lines and scanning lines, and intersections of the data lines and scanning lines. The liquid crystal pixel has at least one two-terminal switching element, and the scanning line, the data line, the liquid crystal pixel, and the two-terminal switching. Control means including a control circuit for controlling the device and the liquid crystal display in response to a control signal from the control means by a scanning signal applied to the scanning line and a data signal applied to the data line. A two-terminal type active matrix liquid crystal display device in which pixels are driven, wherein the control means includes at least a predetermined selection period for writing the electric charge stored in the liquid crystal display pixels by the scanning signal. Prior to the two-terminal type A current application period setting means for setting a current application period for applying a current to the switching element 2; a polarity setting for determining a polarity of a current applied to the two-terminal switching element during the current application period Means, voltage setting means for setting the voltage of the current applied to the two-terminal switching element, and current for setting the number of times of application of the current applied to the two-terminal switching element to an appropriate number This is a two-terminal active matrix liquid crystal display device provided with application frequency setting means 4.

FIG. 8 further includes a plurality of data lines and scanning lines, and liquid crystal pixels provided corresponding to intersections of the data lines and the scanning lines, and the liquid crystal pixels include at least one two-terminal switching. A two-terminal type active matrix liquid crystal display device, comprising: an element; and a liquid crystal display pixel driven by a scanning signal applied to the scanning line and a data signal applied to the data line. The scanning signal is a signal stored in the liquid crystal display pixel. A selection period for writing a load; a current application period for applying a current to the two-terminal switching element prior to the selection period; and a charge period for the liquid crystal display pixels following the selection period. It also shows a method of driving a two-terminal active matrix liquid crystal display device having a holding period for the operation.

Further, in the liquid crystal driving method according to the present invention, the scanning signal includes a first selection period in which a voltage of a first polarity is applied to the liquid crystal display pixel and the two-terminal switching element, and a voltage of a second polarity. And a voltage having a polarity opposite to that of the voltage in the selection period can be applied to the two-terminal switching element in the current application period prior to each selection period.

Further, in the present invention, the scanning signal has a first selection period in which a voltage of a first polarity is applied to the two-terminal switching element and a second selection period in which a voltage of a second polarity is applied to the two-terminal switching element. However, in a current application period prior to each selection period, driving may be performed so as to have a potential equal to a potential in a selection period in which writing with a polarity opposite to that of the selection period is performed.

Still further, in the driving method according to the present invention, the scan signal may include a first selection period in which a voltage of a first polarity is applied to the two-terminal switching element and a second period in which a voltage of a second polarity is applied to the two-terminal switching element. 2 selection periods, and in a current application period preceding each selection period, a voltage having a polarity opposite to that of the selection period and a voltage having the same polarity are applied to the two-terminal switching element. You can also.

In the present invention, the scanning signal has a first selection period for applying a voltage of a first polarity to the two-terminal switching element and a second selection period for applying a voltage of a second polarity to the two-terminal switching element. Then, in a current application period preceding each selection period, a potential equal to a potential of a selection period in which writing is performed in a polarity opposite to that of the selection period, or a potential of a selection period having the same polarity as the selection period. Preferably they have equal potentials.

In the liquid crystal driving method according to the present invention, the scanning signal includes a first selection period in which a voltage of a first polarity is applied to the two-terminal switching element and a second period in which a voltage of a second polarity is applied to the two-terminal switching element. 2 selection periods, and the absolute value of the potential during the current application period prior to each selection period may be set to be greater than the absolute value of the potential during the selection period. The length may be set to be equal to the length of the selection period.

Further, in the liquid crystal driving method according to the present invention, the length of the current application period of the scanning signal may be set longer than the length of the selection period. It may use a selection period of a scanning signal to be applied.

Next, in the liquid crystal driving method of the present invention, the selection period of the scanning signal and the current application period preceding the selection period may be configured to be continuous. Alternatively, a configuration may be employed in which a period having a potential at which no current is applied to the two-terminal switching element is inserted.

Further, when a reference value is an intermediate value between the maximum value and the minimum value that the data signal can take in each period, the reference potential fluctuates in a selection period and a current application period preceding the selection period. You may.

Specific examples of each aspect of the above-described driving method of the liquid crystal display device of the present invention will be described below.

1 (A) to 1 (D) show an embodiment of the driving method according to the present invention. φ (η) and φ (n + 1) are scanning signals applied to the n-th and n + 1-th scanning lines, respectively. This embodiment shows an example of so-called row-by-row inversion as apparent from the selection polarity in each period shown in FIG. Of course, the present invention is not limited to row-by-row inversion, but is also effective with frame inversion and in-row inversion. Scan signal ø (n) is positive polarity The selection period H (n) and the selection period H '(n) of the negative polarity are selected.The scanning signal ø (n + 1) is the selection period H' (n + 1) and the selection period of the negative polarity. It has H (n + 1) and has a selection potential Va1 for positive polarity and Va2 for negative polarity. The period following each selection period corresponds to the holding period, and takes the holding potential Vb1 in the holding period following the selection period of positive polarity, and takes the holding potential Vb2 in the holding period following the selection period of negative polarity. In the present embodiment, the selection periods H (η) are the periods 26 and 31 during which the selection potential Va and Va2 are taken out of Η ′ (η), and some are the holding potentials Vbl and Vb2. May be used as the selection potential.

A feature of the present invention resides in a period preceding the selection period. For the scanning signal ø (n), the periods H (n-1) and H

In (n-2), there is a period during which no holding potential is taken. If this period is called the current application period, it corresponds to 27 and 28 in FIG. The voltage written to and stored in the liquid crystal pixels is determined by the selection potential period 26 of the selection period H (n), and the image immediately before that should not be significantly affected. The present invention is characterized in that a current is applied by applying a large voltage to a two-terminal switching element using this period in which the effect on the image is minimal. Specifically, the period H immediately before the positive polarity selection period H (n)

(n-1) is provided with a period 27 for applying a large potential with a different polarity, here a negative selection potential Va2, and in the previous period H (n-2), a large period with a different polarity from the period 27 is applied. A period 28 for applying a potential, here a positive selection potential Va 1, is provided. The same applies to the negative polarity selection period H '(n) .In the immediately preceding period H' (n-1), a large potential with a different polarity is applied.In this case, the positive polarity selection potential Val is applied. In the period H '(n-2) before that, a large potential having a polarity different from that of the period 32, here a period 33 for applying the negative selection potential Va2 is provided.o In the present embodiment, for example, in the period H (n−1) immediately before the selection period H (n), 29 periods other than the current application period 27 are provided. Similar periods are set for 30, 34 and 35. Such a period is not required. That is, there is no problem even if H (n-1) = 27 and H (n-2) = 28 (However, it is effective to provide 29, 30, 20, 21 depending on the scanning line driver circuit. For example, Va 1 → In the case of a driver circuit that generates a scanning signal that changes in the order of 1 → Va2 → Vb2, the signal of the present invention can be generated without changing the circuit only by changing the timing.

The data signal D (m) applied to the m-th data line takes a potential between the data potentials Vdl and Vd2 as indicated by 25 as in the conventional example of FIG. Either amplitude modulation or pulse width modulation is used for gradation display, and the latter example is shown in FIGS. 1 (A) to 1 (D). Reference numeral 22 denotes a reference potential, which is drawn at a constant potential in this figure, but may fluctuate throughout the system. In FIG. 1, Va and Va2 and Vb and Vb2 are shown symmetrically with respect to the reference potential, but may be asymmetric. Although this example corresponds to the example of inversion of each line, field inversion and in-line inversion may be used.

FIGS. 6A to 6D show scanning signals ø (n) according to another embodiment of the present invention. The timing corresponds to the scanning signal ø (n) used in the embodiment of FIGS. 1 (A) to 1 (D), and the selection period H (η), Η '(η) and the subsequent holding period Are the same and differ only in the current application period.

The current application periods 34 and 35 of the scanning signal ø (η) in the embodiment of FIG. 6 (Α) are the periods 2 (η−1) for two rows immediately before the selection periods Η (η) and Η ′ (η). Η (η-2), Η '(η-1), and Η' (η-2), and have the same polarity and the same potential. When such a method is used in the row-by-row inversion method, the average value of the data signals of the two rows is closer to a constant value than that of the one row, and the current flowing through the switching element during the current application period is reflected in the image 00832 There is a merit that it is hard to depend.

The current application periods 36 and 37 of the scanning signal ø (n) in the embodiment of FIG. 6 (B) are the selection periods H (η) and the periods Η (η−1) and 1 ′ one row before Η ′ (η).

(η-1) and the period 行 (η-3) and Η '(η-3) three rows before, and have the same polarity and the same potential. In the case of the row-by-row inversion method, if Η (η) is the selection period of the positive polarity of the scanning signal ø (η), the period 1 (η-1) one row earlier and the period Η (η-3) three rows earlier Corresponds to the selection period of the negative polarity of the scanning signals φ (η−1) and φ (η−3), respectively. Therefore, in this example, the potential Va2 during the current application period 36 of ø (η) is the same polarity and the same potential as the selection potential of the scanning signal of the simultaneously selected scanning line. Similarly, the potential Va 1 during the current application period 37 has the same polarity and the same potential as the selection potentials of the scanning signals (n−1) and Φ (n−3) of the scanning line selected in the same manner. Assuming that the potential during the current application period has the same polarity as the scanning signal of the scanning line that is selected at the same time, the power supply swing method and FIGS.

The voltage amplitude of the circuit can be reduced by the reference potential fluctuation method of (B). Further, if the potentials are the same, the number of potentials can be reduced.

The current application periods 38 and 39 of the scanning signal ø (n) in the embodiment of FIG. 6 (C) are the periods H (n-2) and Η 'two lines before the selection period H (n) and H' (n).

(η-2) and has the opposite polarity to the potential during the selection period. In periods 40 and 41, the holding potentials Vb2 and Vbl are taken. H for row-by-row inversion

The period H (n−2) two rows before, where (n) is the selection period of the positive polarity of the scanning signal ø (n), corresponds to the selection period of the positive polarity of the scanning signal ø (n−2). Therefore, in this example, the potential Va2 during the current application period 38 of ø (n) is opposite in polarity to the selection potential of the scanning signal of the scanning line selected at the same time. Similarly, the potential Va 1 during the current application period 39 has a polarity opposite to the selection potential of the scanning signal ø (n−2) of the scanning line selected in the same manner. In this way, the potential during the current application period is set to the opposite polarity to the scanning signal of the scanning line selected at the same time. Although this is disadvantageous for the circuit voltage amplitude in the power supply fluctuation method and the reference potential fluctuation method in FIG. 7, there is an advantage in preventing image sticking. In general, the spatial frequency of an image is relatively low, and the gradations of the adjacent n-th and n−2 lines are often similar. For example, assume that n rows and n-2 rows in normal white mode have black (maximum voltage) gradation. In the selection period H (n) of Φ (n), the maximum current flows, but in the current application period, the voltage of ø (n) has the opposite polarity and is the smallest current. Conversely, in the case of white (minimum voltage) gray scale, the current is the minimum during the ø (n) selection period H (n), but becomes the maximum current during the current application period because the voltage of Φ (n) has the opposite polarity. In this way, the current is averaged as a whole and burn-in is minimized.

In the above example, the potentials during the current application period are the same as the selection potentials Va 1 and Va 2, which is very advantageous in terms of saving the number of power supplies in the circuit. However, in the present invention, the potential does not necessarily have to be the same as the selection potential. In the scanning signal ø (n) of the embodiment of FIG. 6D, the potential during the current application period is Vcl in the periods 43 and 44, and Vc 2 in the periods 42 and 45, which is a large potential different from the selection potential. I have.

FIGS. 7 (A) to 7 (B) are in principle completely equivalent to FIG. 1, and the scanning signal is obtained by shaking the reference potential 22 of FIGS. 1 (A) to 1 (D) for each row as 50. This is an example in which the signal amplitude is reduced. Conversely, the data signal amplitude has increased. The drive waveforms look different but are equivalent. The present invention is also applicable to such a fluctuation potential if the reference potential is fixed and described as equivalent. In the above embodiments, the example of the current application period for one or two rows is shown. I do not care. The same applies to both continuous and discontinuous. Similarly, the retention period need not be continuous as long as it is after the selection period. The invention's effect As described in Figs. 4 (A) to 4 (D), the problems of the conventional driving method are described above.The biggest problems of the active matrix liquid crystal display device using the two-terminal switching element are image burn-in and image burn-in. This is an afterimage phenomenon, which is caused by the fact that the threshold voltage Vth of the switching element changes depending on the amount of current flowing. In the present invention, in particular, the current is forcibly applied to the switching element by the provided current application period, and the threshold Vth is changed to stabilize the current, thereby reducing the burn-in and the afterimage.

The effect of the invention will be described with reference to FIG. For example, in the embodiment shown in FIGS. 1A to 1D, two current application periods having different polarities are provided before the selection period, and the current is forcibly applied to the switching element. The current flowing through the device shown in Fig. 5 (C) increases three times as frequently as the current shown in Fig. 4 (C). In the embodiment of FIG. 1, there is still a difference in the amount of current depending on the gradation, but the Vth change amount due to the gradation is smaller in FIG. 5 (D) than in FIG. 4 (D) due to the increase in the absolute amount. As a result, the burn-in 48, 49 appearing in the actual transmittance change in Fig. 5 (B) with respect to the ideal transmittance change in Fig. 5 (A) has been greatly reduced. The improvement effect is slightly larger in Figs. 6 (A), (C), and (D) than in Figs. 1 and 6 (B).

Claims

The scope of the claims

1. It has a plurality of data lines and scanning lines, and a liquid crystal pixel provided corresponding to the intersection of the data line and the scanning line, and the liquid crystal pixel has at least one two-terminal switching element. A method of driving a two-terminal active matrix liquid crystal display device in which a liquid crystal display pixel is driven by a scanning signal applied to a scanning line and a data signal applied to a data line; A selection period for writing electric charges accumulated in the pixel, a current application period for applying a current to the two-terminal switching element prior to the selection period, and a liquid crystal display subsequent to the selection period. A method for driving a two-terminal active matrix liquid crystal display device, characterized by having a retention period for retaining charges of display pixels.

2. The scanning signal includes a first selection period in which a voltage of a first polarity is applied to the liquid crystal display pixel and the two-terminal switching element, and a second selection period in which a voltage of a second polarity is applied. 2. The two-terminal switching device according to claim 1, wherein a voltage having a polarity opposite to that of said selection period is applied to said two-terminal switching element during a current application period preceding each selection period. Driving method of the active matrix liquid crystal display device.

3. The scanning signal has a first selection period in which a voltage of a first polarity is applied to the two-terminal switching element and a second selection period in which a voltage of a second polarity is applied to the two-terminal switching element. 3. The two-terminal type active matrix liquid crystal display device according to claim 2, wherein in a current application period preceding the period, the potential has a potential equal to a potential in a selection period in which writing of a polarity opposite to the selection period is performed. Method.

4. The scanning signal has a first selection period for applying a voltage of a first polarity to the two-terminal switching element and a second selection period for applying a voltage of a second polarity to the two-terminal switching element. In the current application period preceding the period 3. The two-terminal type active matrix liquid crystal display device according to claim 1, wherein a voltage having a polarity opposite to and a voltage having the same polarity as the voltage during the selection period is applied to the two-terminal switching element. Drive method.

5. The scanning signal has a first selection period for applying a voltage of a first polarity to the two-terminal switching element and a second selection period for applying a voltage of a second polarity to the two-terminal switching element. The current application period preceding the period has a potential equal to a potential of a selection period in which writing is performed in a polarity opposite to that of the selection period, or a potential equal to a potential of a selection period having the same polarity as the selection period. 4. A method for driving a two-terminal active matrix liquid crystal display device according to item 4.

6. The scanning signal has a first selection period for applying a voltage of a first polarity to the two-terminal switching element and a second selection period for applying a voltage of a second polarity to the two-terminal switching element. 2. The method for driving a two-terminal active matrix liquid crystal display device according to claim 1, wherein the absolute value of the potential during the current application period prior to the period is larger than the absolute value of the potential during the selection period.

7. The method of driving a two-terminal active matrix liquid crystal display device according to claim 1, wherein the length of the current application period of the scanning signal is equal to the length of the selection period.

8. The method of driving a two-terminal active matrix liquid crystal display device according to claim 1, wherein the length of the current application period of the scanning signal is longer than the length of the selection period.

9. The two-terminal type active matrix liquid crystal display device according to claim 1, wherein the current application period of the scanning signal uses a selection period of a scanning signal applied to another scanning line. Method.

10. The two-terminal activator according to claim 1, wherein a selection period of said scanning signal and a current application period preceding said selection period are continuous. A method for driving a Bumatrix liquid crystal display device.

11. The two-terminal type according to claim 1, wherein a period having a potential at which no current is applied to the two-terminal switching element is inserted between the current application period and the selection period of the scanning signal. Active matrix A method for driving a liquid crystal display device.

12. When the intermediate value between the maximum value and the minimum value that the data signal can take in each period is set as a reference potential, the reference potential fluctuates during a selection period and a current application period preceding the selection period. A method for driving a two-terminal type active matrix liquid crystal display device according to claim 1, wherein

13. It has a plurality of data lines and scanning lines, and liquid crystal pixels provided corresponding to intersections of the data lines and the scanning lines, and the liquid crystal pixels have at least one two-terminal switching element. And control means including a control circuit for controlling the scanning line, the data line, the liquid crystal pixel, and the two-terminal switching element, and in response to a control signal of the control means. A two-terminal active matrix liquid crystal display device in which liquid crystal display pixels are driven by a scan signal applied to the scan line and a data signal applied to a data line,

The control means applies a current to the two-terminal switching element 2 at least prior to a predetermined selection period for writing the charge stored in the liquid crystal display pixel by the scanning signal. Current application period setting means for setting an application period, polarity setting means for determining the polarity of a current applied to the two-terminal switching element during the current application period, and a two-terminal switching element. Provided with voltage setting means for setting the voltage of the applied current and current application number setting means 4 for setting the number of application of the current applied to the two-terminal switching element to an appropriate number. A two-terminal active matrix liquid display device, characterized in that: