JPS5827876B2 - Display device drive method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a single drive force type display device.

Conventionally, there have been the following types of watches that statically drive a liquid crystal display to display the time in analog form.

A selection electrode group consisting of a plurality of selection electrodes is made to face each divided control electrode through a liquid crystal, and by controlling the application time of the voltage applied between the control electrode and the selection electrode, the control electrode, liquid crystal and Controls display and non-display of display segments consisting of selected electrodes.

For example, a voltage equal to or higher than a duty 2/3 threshold voltage is applied to a display segment to be displayed, and a voltage equal to or higher than a voltage O or a duty 1/3 threshold voltage is applied to a display segment to be hidden. Ta.

However, according to this method, some display segments that should be hidden are also displayed to some extent, resulting in poor contrast between display and non-display, which is not desirable.

Therefore, the present invention eliminates the above-mentioned drawbacks by applying at least two types of voltages to display segments that should be displayed, and applying one type of voltage to display segments that should not be displayed to perform integrated display. It is something.

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 shows a display device driven by this driving method.

FIG. 2 is an exploded view of the main parts of the display device shown in FIG. 1. 1 is a glass substrate, and 12
Equally divided fan-shaped control electrodes 2, 3...13 are provided electrically independently, and each electrode is connected to a lead wire 2.
a, 3a...13a.

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, selection electrodes a1. a2. ...312 + blt
b2'''b12...ell, e2-...e, 2 are provided.

Selection electrodes a,, bl, =-el, a2.
b2...-e2...a1□ and b12...el2 respectively select the selected electrode group A1. A2. ... constitutes A12.

Control electrode 2゜3...13, liquid crystal and selection electrode al, b,...e1a2! b2"'e2"
"'12+b121"/el2 constitutes a display segment.

Selection electrode a1. a2゜...a bb...b
...elt e2F ...e1212
9Is212 are each connected to a common lead wire p0. It is connected to p2...p5.

Note that two polarizing plates having polarization axes parallel to each other are provided on the outside of the glass substrates 8 and 14.

FIG. 3 shows one driving circuit that causes the display device shown in FIG. 1 to display an integrated display every second.

15 is a crystal oscillator, and 16 is a frequency division stage.

1T is a control electrode selection pulse generation circuit, which is composed of a flip-flop circuit and a gate circuit.

This output terminal 17a, 17b・A 7kI is the 4th A,
B...K Pulses are generated as shown in the diagram.

Reference numeral 18 denotes a selection pulse generation circuit for the selection electrode, which is composed of a flip-flop circuit and a gate circuit.

The pulse generating circuits 17 and 18 described above are used in this type of drive circuit.

This output terminal 18a. 4th S1 for 18b...18e
．． S2...S5 As shown in the figure, a pulse with a period of 5 seconds is generated.

19 is a voltage selection supply circuit.

20 is a selection electrode 1 drive circuit, and this output terminal rn1
．． Pulses shown in the fifth M12M2...M5 are generated in rn2...m5.

21 is a control electrode drive circuit, and this output terminal nl+
n2...n12 has the 5th N1. N2...N1□The pulse shown in the figure is generated.

Although FIG. 5 shows that pulses are generated at a period of 1 second for the sake of explanation, in reality, pulses of about 50 Hz are generated.

FIG. 6 shows a voltage selection supply circuit 199 and a selection electrode drive circuit 2.
0 and a control electrode drive circuit 21 are shown.

22, 23. . . . 54 is a transfer element such as a transfer gate or a semiconductor switching element; 55. 56
．． . . 60 is a gate circuit 61, 62 . . . 74 is an inverter.

Next, the operation will be explained.

For the following explanation, it is assumed that the liquid crystal has voltage-transmitted light amount characteristics shown in FIG.

In the figure, ■ is the voltage, and a is the amount of transmitted light.

In Fig. 6, the terminal P has 50H, which should drive the liquid crystal with AC.
A pulse with a frequency of approximately z is supplied, and when this pulse is at a high level, the transmission element 45°47.49,51,
53 is turned on, and terminals u1, u2...u5 have potentials of 4V, 3V, and 2V, respectively.

5V, held at 0.

Also, when the pulse becomes low level, the transmission element 46. 4
8. 50. 52. 54 is turned on, and the terminal u1.
u2...u5 respectively at potentials V, 2V, 3V, 0, 5
Hold at V.

Therefore, depending on the level of the pulse supplied to the terminal P, the terminal u1. u2...u5 are each (4■.

V) (3V, 2V), (2V, 3V)) (5V.

) o) and (0.5V) are held alternately.

Therefore, as an example, if the pulse of FIG. 4B is applied to terminal 1γb,
Looking at the state in which the pulse shown in FIG. 482 is supplied to the terminal 18b, when the terminal 18b is at a low level, the transmission element 3
8 is turned on, terminal m2 is at the potential of terminal u2 (3V,
2V).

Further, when the terminal 18b is at a high level, the transfer element 37 is turned on, and the terminal m2 is at the potential of the terminal u4 (5■).

O).

On the other hand, when both terminals 17a and 17b are at a low level, the transfer element 26 is turned on, and the terminal n2 is at the potential of the terminal u1 (4
V, V).

When the terminals 17a and 17b are at a high level and a low level, respectively, the transfer element 24 is turned on, and the terminal n2 is held at the potential of the terminal u3 (2V, 3V).

When the master terminal 17b is at a high level, the transfer element 25 is turned on, and the terminal n2 is held at the potential of the terminal U (0°5V).

Due to the potential generated in this way, a voltage is applied between the terminals n2 and m2 as shown in Table 1.

Between terminals n2 and rn2 (voltage (L V), (3V
.

3V), (-5V, 5V) are selectively applied.

Therefore, the saturation voltage V shown in FIG.

When the above voltages (-3V, 3V), (-5V, 5V) are applied, the liquid crystal remains responsive and the display segment becomes bright.

When a voltage below the threshold voltage is applied, the liquid crystal remains unresponsive and the display segment becomes dark.

Similar voltages are applied between other terminals as well.

In this way, each terminal rn1. rn2...m5 and the fifth M1.N2/N5. to terminal n1"2""12.
N1. N2...N1□ pulses are generated, and each terminal n
x-my(x'=1.2...12.y=1.2・
. . . 5) The pulses shown in the 8th diagram X1°X2 . . . X6o are applied between them.

Therefore, in the display device shown in FIG. 1, the display is incremented one second at a time, and cumulative seconds are displayed.

In Figure 1, the hatched part is displayed brightly, and 5※※
Displaying seconds.

By the way, the voltages applied to the liquid crystal are not limited to those mentioned above, and may be applied as shown in Table 2.

The terminal my has potentials (4V, 2V) and potentials (2V, 4V).
V) is selectively supplied, and the potential (0,6 V) is supplied to the terminal nx.
, potential (V, 5V) and ■.

However, the potential (0.6V) is the potential (4■.2V), the potential (
2V, 4V) and the potential (V, 5V) at half the period.

In order to realize this voltage application, the circuit shown in FIG. 9 may be used in place of the voltage selection supply circuit 19 shown in FIG.

In FIG. 9, 75, 76, . . . , 82 are transmission elements, and 83, 84, 85, 86 are inverters.

With the above configuration, the terminal q is supplied with a pulse having a frequency for alternating current driving of the liquid crystal, and the terminal r is supplied with a pulse having a period of 1/2 of that frequency.

Therefore, terminal u1. u2. u3. Each u4 has a potential of 3V.

(2V, 4V), (V, 5V), (4V, 2V) are generated, and the potential (0, 6V) is generated at the terminal u5 in half the period.
occurs.

Terminal u1. The potentials generated at u2, . . ., u5 are changed to the terminals n1, . n2
．． By supplying voltages (-3V, 3V) to n12 and terminals m12m2...m5 as shown in Table 2.
, (V, -V) and the voltage (-4V,
2V), (-2V, 4V) are selectively applied to the liquid crystal,
Voltage (-3■, 3v) (-4V, 2V), (-2V, 4
The liquid crystal is held in a responsive state by the voltage (V,
-V) is held in a non-responsive state.

By the way, when this voltage application method is used, the voltages applied to the display segments to be displayed are the same or the difference between them is small, so that the contrast becomes uniform, which is most preferable.

Note that in the above two embodiments, the terminal u1. The voltages generated at terminals u5 and u2.
By replacing the voltages generated at u4, the brightness and darkness of the display can be reversed.

In addition, in this case, the two polarization axes are shifted by 90°.
If two polarizing plates are provided outside the glass substrates 8 and 14 shown in FIG. 2, a display similar to that of the above embodiment can be obtained.

Further, although a field effect type liquid crystal was used in the above embodiment, a dynamic scattering type liquid crystal may also be used.

Further, in the above embodiment, a liquid crystal is used as the electro-optical display element, but the present invention is not limited to this, and a dipole suspension or the like may be used.

As detailed above, according to the present invention, at least two types of display voltages are applied to the display segments to be displayed, and one type of non-display voltage is applied to the display segments to be hidden, and the integrated display is performed. As a result, the contrast of the display becomes uniform, a high-contrast display with quick response can be obtained, and the number of lead wires for supplying voltage to the display device can be reduced.

[Brief explanation of drawings]

Figure 1 is a front view showing an example of a display device driven by this drive method, Figure 2 is a developed view of the main parts of Figure 1, and Figure 3 is a drive circuit for realizing the drive method. A block diagram showing an example of the block diagram, Figures 4 and 5 are
A time chart for explaining the figures, Figure 6 is an electrical circuit diagram showing in detail an example of the main part of Figure 3, and Figure 7 shows the voltage-transmitted light amount characteristics of the liquid crystal used in this example. Characteristic diagram,
FIG. 8 is a time chart for explanation, and FIG. 9 is an electric circuit diagram showing the main parts of the circuit for realizing the voltage application shown in Table 2. 2.3...13: Control electrode, A1. A2...A12
: Selected electrode group, al, a2...a1□, bl, b2...
...b12°'-e,. e2...e1□: Selection electrode.

Claims (1)

[Claims] 1 A selection electrode group is made to face each of the plurality of divided control electrodes via an electro-optic display element, and the selection electrodes,
In a driving method for sequentially and cumulatively displaying display segments constituted by an electro-optical display element and a control electrode, a control pulse signal having four or more different amplitude values to be applied to the control electrode is generated, and the control pulse signal is applied to the control electrode. A selection pulse signal having two or more different amplitude values to be applied to a selection electrode is generated, and the electro-optic display element is displayed and hidden by selective combination of the control pulse signal and the selection pulse signal. Set the polarized pulse signal to
A single driving force type display device in which a polar pulse signal for non-display is applied to a display element in a non-display state, and a polar pulse signal for display is sequentially applied to one display element that is to display an integrated display.