JP2851315B2 - 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, and two-terminal switching elements including a liquid crystal display pixel 10 and diode groups 20 and 21 are arranged corresponding to their intersections. . 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 switching element 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 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 T _B are signals for selecting line-sequential in the sections T _A1 , T _A2 , T _A3 and T _B1 , T _B2 , T _B3 . As for the scanning signals phi _1, first the write period T _W1 first write voltage V _W1
Is the second write voltage V in the second write section _TW2 .
_W2 is the first holding voltage V _H1 in the first holding section T _H1 .
Holding voltage V _H2 of the holding section T in _H2 second is applied. Feature of the scanning signal is that the reset period T _R of the reset voltage V _R is applied immediately before the first write section 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. At the timing of the write section in which the write voltage is the first write voltage, the difference between the maximum voltage and the minimum voltage is V _H1 −V _W1 ,
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 conventional method of driving a two-terminal type active matrix liquid crystal display device by modifying the scanning signal. That is, it is characterized by using a scanning signal in which a third holding section is provided between a reset section and a writing section, which have been conventionally continuous.

〔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 and T interval T _A1 of _B, T _A2, T _A3 and T _B1, T _B2, line-sequentially the signal selected by the T _B3 is there. As for the scanning signals phi _1, first the write period T _W1 first write voltage V _W1 is second in the write section T _W2 second write voltage V _W2 is, in the first holding section T _H1 First holding voltage V
_H1 is, the second holding section T _H2 in the second holding voltage V _H2 is the reset voltage V _R the reset period T _R is applied. The feature of this scanning signal is that a third holding section is provided between the reset section and the first writing section.

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, a third holding section is provided between the reset section and the first writing section. As a result, conventionally, the reset section corresponds to the first write section of a scan signal of a different polarity applied to another scan line, whereas in the present invention, the reset section is applied to the other scan line. This makes it possible to correspond to the first write section of the polarity scanning signal. For this,
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 this embodiment, the first
The difference between the maximum and minimum voltages at the timing of the write voltage writing period of the V _H1 -V _W2 at the timing of V _R -V _W1, write section of the second write voltage. Unlike the conventional example, the difference between the maximum voltage and the minimum voltage is lower than the peak-to-peak voltage 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 the difference V _W1 −V _W2 between the first and second selection voltages. In FIG. 5, the modulation is performed at the difference V _H1 −V _H2 between the first and second holding voltages. V _H1 −V _H2 is V _W1 −V
_Although it may be slightly smaller than _W2, it may be set the same as in this embodiment. Figure 5 X V _H1 -V _H2 = Subtracting the modulated signal at a from the scanning signal of FIG. 1 FIG. 5 of the scanning signals phi ₁ ^** shown in, φ ₂ ^**, φ ₃ ^**, and the The operating voltage can be saved by V _W1 −V _W2 = V _H1 −V _H2 .

The third holding voltage applied to the third holding section
If V _H3 is substantially equal to the first holding voltage V _H1 or the second holding voltage V _H2 , it is easy to do on the drive circuit, and in this embodiment, it is the same as V _H1 . However, of course, other voltages may be used.

〔The invention's effect〕

As described above, in the present invention, by providing the third holding section between the conventional reset section of the scanning signal and the first writing section, the reset voltage which is the maximum voltage of the scanning signal is provided.
The second write voltage V _W2 is V _R and the minimum voltage can be avoided that the simultaneous presence. 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 of the present invention, and FIGS. Circuit diagram showing the basic configuration of a liquid crystal active matrix liquid crystal display device, FIG.
FIG. 5 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. 5 is a waveform diagram showing another embodiment of the scanning signal in the driving method of the present invention. . 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, a reset section, and a third holding section. The reset section is the first section of the same polarity scanning signal applied to another scanning line. A method for driving a two-terminal active matrix liquid crystal display device, wherein the method corresponds to a writing section. 2. The two-terminal active matrix liquid crystal according to claim 1, wherein the third holding voltage applied to the third holding section is substantially equal to the first holding voltage or the second holding voltage. A method for driving a display device.