JP2859313B2 - Driving method of two-terminal type active matrix liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] Liquid crystal display elements are widely applied as flat panel displays with low power consumption. Among them, an active matrix method in which a switching element is formed in each pixel and driven is being used as a large-capacity, high-quality display element in televisions, information terminals, and the like. 3 for switching element
A terminal type TFT (thin film transistor) and a non-linear resistance element such as a two-terminal type diode or MIM are used. Commercialization is 3
Terminal type TFTs preceded, but the two terminal type is easier to manufacture than the three terminal type, and future prospects are expected.

The present invention relates to a method for driving a two-terminal type active matrix liquid crystal display device using two-terminal type switching elements.

[Conventional technology and its problems]

2 and 3 show a basic arrangement of pixels of an active matrix liquid crystal display element using a conventional two-terminal switching element.

FIG. 2 shows a system filed by Philips (JP-A-64-33534, JP-A-64-33532). C1, C2, and C3 are data lines 5, R1, R2, and R3 are scanning lines 6. A liquid crystal display pixel 10 and diode groups 20 and 21 correspond to intersections of the data lines 5 and the scanning lines 6.
A terminal type switching element is arranged. Each diode 22 is usually formed of a pin junction or a Schottky junction of amorphous silicon.

FIG. 3 shows a system applied by the present applicant. (Japanese Patent Application No. 1-88911), a two-terminal type switching composed of a liquid crystal display pixel 10 and one diode 13 at the intersection of a data line (or scanning line) 5 and a scanning line (or data line) 6 An element is provided.

FIG. 4 shows the scanning signals used in the system shown in FIGS.

The scanning signals φ ₁ , φ ₂ , φ ₃ correspond to the respective fields T _A
And a period T _A1, T _A2, T _A3 and T _B1, T _B2, the signal line are sequentially selected by T _B3 of T _B.

As for the scanning signal phi _1, the first write section T
_{In W1} , the first write voltage V _W1 is changed to the second write period T
The second write voltage V _W2 at _W2 is, first the holding period T _H1 first holding voltage V _H1 is, the second holding section T _H2 in the second holding voltage V _H2 is applied. The characteristics of this scanning signal are as follows.
It is that the reset period T _R of the reset voltage V _R is applied immediately before the writing period T _W1 is provided.

Operating voltage for supplying the conventional scanning signal V _R -V _W2
Becomes

FIG. 4Z shows the maximum voltage 41 and the minimum voltage 42 at each timing of the scanning signal group in FIG. In this embodiment, since the so-called row-by-row inversion method is used, the maximum voltage 41 and the minimum voltage 42 vary depending on the polarity of the write voltage of the scanning signal. When the write voltage is in the write period of the first write voltage, the timing is V _H1 −V _W1 after the maximum voltage and the minimum voltage,
At the timing of the write section of the second write voltage, V _R
−V _W2 .

It is known that in order to save the operating voltage of the driving circuit, the operating voltage of the driving circuit can be set to the difference between the maximum voltage and the minimum voltage. However, the difference between the second of the maximum voltage and the minimum voltage at the timing of the write voltage writing period of not save V _R -V _W2, and the peak-to-peak voltage and equal to the operating voltage of the scanning signal as described above.

The present invention is directed to overcoming the disadvantages of the prior art. That is, an object of the present invention is to provide a method of driving a two-terminal type active matrix liquid crystal display device which can greatly reduce the operating voltage of a driving circuit for supplying a scanning signal.

[Means for solving the problem]

The present invention improves the driving method of the conventional two-terminal type active matrix liquid crystal display device by adding a device to the scanning signal. That is, the present invention is characterized in that a scan signal in which a reset section, which conventionally uses a write section of another scan line, is provided in a horizontal retrace section is used.

〔Example〕

 Hereinafter, the present invention will be described based on examples.

FIG. 1 is an embodiment of a scanning signal waveform in a method for driving a two-terminal type active matrix liquid crystal display device according to the present invention.

Scanning signal _{^{Φ 1 *, Φ 2 *,}} Φ 3 * in each field T _A, section _{T B T A1, T A2,} T A3 and T _B1, T _B2, line-sequentially the signal selected by the T _B3 is there. Each section T _A1 ,
T _A2 , T _A3 and T _B1 , T _B2 , T _B3 are used as a part of a first writing section or a second writing section T _W of each scanning signal and a holding section of another scanning signal that follows thereafter. It is composed from the section T _R is. The interval T _R suitably is a position that does not also used section as a write section of which the scanning signal after the write section of a video signal used in the conventional CRT, respectively the scanning signal in the horizontal blanking interval and call it has since the present invention It is referred to as an upper horizontal retrace interval. Regarding the scanning signal Φ ₁ ^* , the first write voltage V _W1 is applied in the first write interval T _W1 , the second write voltage V _W2 is applied in the second write interval T _W2 , and the first holding interval T _{H1 is applied.} Now the first holding voltage
V _H1 is the second holding voltage V _H2 in the second holding section T _H2 ,
In the reset sections T _R1 and T _R2 , a reset voltage V _R is applied. The feature of this scanning signal Φ ₁ ^* is that the reset section is a horizontal retrace section TR1 after the selection section of the scanning signal applied to the scanning line immediately before this scanning signal Φ ₁ ^* , and one more before that. in that provided in the horizontal blanking interval T _R2 after the selection period of the scan signal to the scan lines.

Z ^* in FIG. 1 shows the maximum voltage 11 and the minimum voltage 12 at each timing of the scanning signal group in FIG. In this embodiment, the reset section is provided in the horizontal retrace section. As a result, while the reset section conventionally corresponds to the first write section of a scan signal of a different polarity applied to another scan line,
In the present invention, the reset section can be made to correspond to the holding section of another scanning signal. Therefore, the reset voltage which is the maximum voltage of the scanning signal and the minimum voltage _VW2 do not occur at the same time. As a result, in the present embodiment, the difference between the maximum voltage and the minimum voltage is V _H1 −V _W1 or V
_H1 -V _W2, the V _R -V _H2 at the timing of the horizontal blanking interval. Unlike the conventional example, the difference between the maximum voltage and the minimum voltage is lower than the peak-to-peak voltage V _R -V _W2 of the scanning signal, so that the operating voltage of the driving circuit can be saved.

FIG. 5 shows another embodiment of the modulated scanning signal in which the operating voltage is reduced by using the scanning signal of the embodiment of FIG.
The maximum modulation amplitude possible from FIG. 1 Z ^* is V _W1 −V _W2 or V _R −
V _H1 . In FIG. 5, the difference between the first and second holding voltages V _H2 −
Modulation was performed at V _W2 = a. The amplitude V _H2 −V shown in FIG.
_W2 = a modulated signal scanning signals phi ₁ ^** next operating voltage is subtracted from the scanning signal of FIG. 1 FIG. 5 can be saved only V _H2 -V _W2 minutes.

In this embodiment, two horizontal flyback sections T _R1 and T _R2 are used as reset sections. In the shortest section, one horizontal retrace section may be used, but in order to keep the reset voltage low, it is effective to use two or more horizontal retrace sections as described above.

〔The invention's effect〕

Above mentioned as in the present invention by a reset interval of the conventional scanning signal provided to the horizontal blanking interval, a second write voltage V _W2 is the reset voltage V _R and the minimum voltage is a maximum voltage of the scanning signal is simultaneously You can avoid being. As a result, the operating voltage of the circuit for supplying the scanning signal can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a waveform diagram showing a scanning signal in an embodiment of a method for driving a two-terminal type active matrix liquid crystal display device according to the present invention. FIGS. 2 and 3 are both two-terminal type active matrices according to the prior art. FIG. 4 is a circuit diagram showing a basic configuration of a liquid crystal display device, FIG. 4 is a waveform diagram showing a scanning signal in a driving method of a conventional two-terminal type active matrix liquid crystal display device, and FIG. FIG. 9 is a waveform chart showing another example of the scanning signal. 5 ...... data line, 6 ...... scanning lines, 10 ...... liquid crystal display _{^{pixel, φ 1 *, φ 2 *}} , φ 3 * ...... scan signal.

Claims (2)

(57) [Claims] 1. A scanning device comprising: data lines and scanning lines arranged in a matrix; a liquid crystal display pixel provided at an intersection of the data lines and the scanning lines; and at least one two-terminal switching element; In a driving method of a two-terminal type active matrix liquid crystal display device in which a liquid crystal display pixel is driven by a scanning signal applied to a line and a data signal applied to the data line, the scanning signal includes a first writing period and It has a first holding section, a second writing section, a second holding section, and a reset section, and performs scanning after the first writing section and the second writing section of the scanning signal applied to each scanning line, respectively. There is a horizontal blanking interval which is located after the signal writing interval and is not used as any scanning signal writing interval, and the scanning signal reset interval is before the first writing interval. The driving method of another two-terminal active matrix liquid crystal display device, characterized in that provided in the horizontal blanking interval after the writing period of the scanning signal of the scanning line. 2. The two-terminal active matrix liquid crystal display device according to claim 1, wherein the reset section is provided over a plurality of horizontal retrace sections after a write section of another plurality of scanning lines. Drive method.