JPS5913037B2 - Display device driving method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for driving a display device.

Conventionally, the following methods have been used to statically drive a liquid crystal display device.

By applying periodic pulses with different widths to both electrodes of a liquid crystal display element, pulses are applied periodically between both electrodes, and the time and rate of the pulses applied within one period are varied. In particular, the liquid crystal could be made responsive or non-responsive. However, according to this method, a narrow pulse was applied to the liquid crystal which should be made non-responsive, or the applied voltage was the voltage o, resulting in uneven display. o Therefore, the present invention provides a static driving method for displaying a display element with uniform contrast. Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an example of a display 5 device that performs display using the present driving method. FIG. 2 is an expanded view of the main parts of the display device shown in FIG. 1, where 1 is a glass substrate;
Control electrode 2 constituting a fan-shaped first electrode that divides the glass substrate 1 into 12 equal parts...1
3 are provided electrically independently, and each electrode is connected to a lead wire 2a......13a.
It is connected to.

A glass substrate 14 faces the glass substrate 1 with a spacer 14a and a field effect liquid crystal interposed therebetween.

On the surface of the glass substrate 14 in contact with the liquid crystal, there are selection electrodes a1 constituting the second electrode divided into 5 equal parts of 60.
...,,,a123bl,...,,0,,song,,
b123e,...,,,,゜゜,... e12 is provided. Selective electrodes a,, bl...
...el, a2, b2゜゜゜゜゜゜゜゜゜゜゜゜゜゜゛゜e2゜゜゜゜゜゜゜゜゜゜゜'゜゜゜a12, b
12・・・・・・・・・・・・・・・E12 selects electrode group '0A4・・・・・・・・・・・・・
... constitutes A12. Control electrode 2...
......13, liquid crystal and selection electrodes a7, b,
...0,,,0,,,,,el3a23b2,,
,,Song...,,,,e2...,1,...・・・
・a, 2, b, 2, ・・・・・・・・・・・・・e
42 constitutes a display element. Selective electrode al...
・・・・・・・・・・・・・a, 2, 15bll,,,
, , , , , , b12I , , , , , , , , , , , , , , , , , , , , , ,
,・el,・,・,,,,,,. e12 is the common lead wire P1・・・・・・・・・・・・P5
It is connected to. 15 and 16 are polarizing plates each having a polarization axis shifted by 90 degrees.

FIG. 3 shows a drive circuit for the display device of FIG. 1. 17 is a crystal oscillation circuit, and 18 is a frequency division stage.

19 is a drive pulse generation circuit, and its output terminal 19a
, 19b, and 19c generate the pulses shown in FIG. 4, A, B, and C, respectively.

These pulses are for alternating current driving of the liquid crystal, and their phases are shifted by % period. Reference numeral 20 denotes a control electrode selection pulse generation circuit, which is composed of a flip-flop circuit and a gate circuit.

Its output terminal 20a......2
At 0k, each figure 5A...
...A pulse is generated as shown in E. Reference numeral 21 denotes a selection pulse generation circuit for the selection electrode, which is composed of a flip-flop circuit and a gate circuit.

Its output terminal 21a......2
From 1e to Fig. 5S, respectively...
...A pulse with a width of 1 second is generated as shown in S5. The selection pulse generation circuits 20 and 21 described above are conventionally used in this type of drive circuit, and their details will be omitted. 22 is a voltage selection supply circuit.

23 is a selection electrode drive circuit whose output terminals M, . . .
・・・・・・・・・・・・M5 is shown in Figure 6 M1...
・・・・・・・・・・・・M5 pulse is generated.

24 is a control electrode drive circuit whose output terminals N,...
・・・・・・・・・・・・Nl2 is shown in Figure 6 N1...
・・・・・・・・・・・・N, 2 pulses are generated.

FIG. 7 shows a voltage selection supply circuit 22 and a selection electrode drive circuit 23.
and an example of the thoracic electrode drive circuit 24 are shown. 25...
・・・・・・・・・・・・47 is a transfer element such as a transfer gate or a semiconductor switching element, 48...
. . . 57 is an inverter.

Next, the operation will be explained. For the purpose of explanation below, the liquid crystal is the 8th
It is assumed that the voltage-transmitted light amount characteristic shown in the figure is obtained.

In the figure, v is the voltage and α is the amount of transmitted light. In FIG. 7, when pulses are sequentially supplied to terminals 19a, 19b, and 19c, pulses of potential V are sequentially generated at terminals U, , U2, and U3.

As an example, if we consider a state in which the pulse shown in FIG. 5B is supplied to the terminal 20b and the pulse shown in FIG. The pulse of the terminal U3 is generated at the terminal M2. Also, when the terminal 21b has a logical value 2, the transfer element 37 is turned on, and the pulse of the terminal U is generated at the terminal M2. On the other hand, the terminal 20b is at the logic value of When is the transmission element 27
is turned on, a pulse from the terminal U1 is generated at the terminal N2, and when the terminal 20b is in the negative state, the transmission element 28 is turned on, and a pulse from the terminal U2 is generated at the terminal N2. FIG. 9 shows the voltage waveform applied between the terminals N2m2 due to the pulses generated in this manner.

A polar pulse of voltage 0 or voltage 1V1 is applied between terminals N2 and M2, but since the polarizing plates 15 and 16 whose polarization axes are shifted by 90 degrees are provided, the voltage 1 that is higher than the saturation voltage is applied.
When V1 is applied, the liquid crystal remains responsive and the display element becomes dark. When the applied voltage is O, the liquid crystal is held in a non-responsive state and the display element becomes bright. Similar voltages are applied between other terminals as well.

In this way, each terminal m1...
・・M5 and terminal N, ・・・・・・・・・・・・・・・
・N, 2 to Figure 6 M1・・・・・・・・・・・・・・・
M5 and Figure 6 N1・・・・・・・・・・・・・・・
N,2 pulses are generated, and each terminal -My(x=1,2
・・・・・・・・・・・・・・・12, y=1, 2...
・・・・・・・・・・・・・・・5) In between, there is a figure 10
.........The pulse of X6O is applied. Therefore, in the display device of FIG. 1, the display is incremented one second at a time to display seconds. In FIG. 1, the hatched area is displayed brightly and indicates 5 seconds.
In the above example, the polarization axes of both polarizing plates are made parallel,
The brightness and darkness of the display may be reversed.

Further, in the above embodiment, a liquid crystal is used for the electro-optic modulation section, but the present invention is not limited to this, and a dipole suspension or the like may be used.

Further, as in the above embodiment, it is most preferable that the voltage applied to the display element to be non-responsive is 0, but this is not limited to this, and if the contrast with the display element that is to respond is sufficient, a minute voltage can be applied. may be applied.

As detailed above, according to the present invention, pulses having the same waveform and the same phase are applied to the first electrode and the second electrode constituting the display element to be selected, respectively, to make the liquid crystal non-responsive.
Pulses with the same waveform and different phases are applied to the first and second electrodes constituting the display element to be unselected to make the liquid crystal respond, so there is no crosstalk and the contrast is uniform. A clear and clear display can be obtained.

However, since it is only necessary to supply the first and second electrodes of the display element with pulses of a constant period shifted in phase, the circuit configuration is simplified. Furthermore, a first electrode and a second
When the duty of the pulse applied to the electrode is expressed as %, the application time within one cycle of the pulse applied to the liquid crystal to be responded is long, so low voltage driving can be performed and the response speed is fast.

[Brief explanation of the drawing]

FIG. 1 is a front view of a display device driven by the present driving method;
2 is a developed view of the main parts of FIG. 1, FIG. 3 is a block diagram showing an example of a circuit that drives the display device of FIG. 1, and FIGS. Figure 7 is an electric circuit diagram showing the main parts of Figure 3 in detail, Figure 8 is a characteristic diagram showing the characteristics of the liquid crystal used in this example, Figure 9 is a time chart for explaining the operation of the figure. 1 is an explanatory diagram showing an example of a voltage application method, and FIG. 10 is a time chart for explaining the operation of FIG. 3. 2-13...First electrode, A, ~Al2~E,
~El2... Second electrode.

Claims (1)

[Claims] 1. A plurality of first electrodes are provided, a plurality of second electrodes are provided opposite each of the first electrodes via a liquid crystal, and a display element is controlled by the first electrode, the liquid crystal, and the second electrode. In the driving method of the display device, a first pulse of a constant period is applied to a first electrode to be selected, and a first pulse is applied to a first electrode to be unselected.
A second pulse with the same waveform and different phase as the first pulse is applied, and a pulse with the same waveform and phase as the first pulse is applied to the second electrode to be selected to make the liquid crystal non-responsive. and the second electrode, which is to be unselected, receives the first pulse and the second pulse.
A method of driving a display device in which a third pulse having the same waveform and a different phase as each of the pulses is applied to cause a liquid crystal to respond. 2. The method for driving a display device according to claim 1, wherein the first pulse, the second pulse, and the third pulse are pulses with a duty of 1/3.