JPS5851276B2 - Driving method of liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving a liquid crystal display device that displays bar graphs and the like.

2. Description of the Related Art Conventionally, there have been devices in which a liquid crystal display device is statically driven to display an integrated value such as a bar graph in the following manner.

As shown in FIG. 8, two sets of liquid crystal panels P1. A polarizing plate A is sandwiched between P2, and two polarizing plates A are placed on the outside.

The configuration includes A.

It is assumed that each polarizing plate has parallel polarization axes.

LCD panel P. A common electrode C8 is provided on the glass substrate G1o, and a common electrode C8 is provided on the glass substrate G2o facing the liquid crystal LC1.
The divided electrodes 01...C5 are formed.

Further, on the glass substrate G3o of the liquid crystal panel P2, divided electrodes 01'...05 similar to the above divided electrodes C1...C6 are provided.
', and each divided electrode 01'...0 is placed on the glass substrate G4o.
5', ten divided electrodes S1...810 are formed in a zigzag pattern through the liquid crystal LC2.

Note that the liquid crystals LC1 and LC2 are both of twisted nematic type.

The residual divided electrodes C1...C6 are each divided electrode 0.
, /...C,, / are connected.

In the above configuration, the common electrode C8 is always maintained at a voltage O as shown in the first column of FIG.

On the other hand, divided electrodes C1...0. > and C0'...05
′ commonly has a voltage of 0. By selectively applying V, 2V (V is the saturation voltage of the liquid crystal) and selectively applying the voltages V, 3V in the ■ column to the divided electrodes S, . . . 810,
This is a bar graph display.

For example, when displaying the numerical value 15, the divided electrode C1,0
Apply voltage 2■ to 1', voltage ■ to divided electrode C2, 02',
Voltage O is applied to divided electrodes C3...C6, C3'...05'
Apply.

As a result, 2V and V are applied to the liquid crystal LO1 facing the divided electrodes C1 and C2, and in response, the long axes of the molecules are aligned in the direction of application of the electric field.

Further, the voltage applied to the liquid crystal LC1 facing the divided electrodes C3...C5 becomes O, and becomes non-responsive, resulting in an alignment state twisted by 90 degrees.

Since the polarization axes of polarizing plates A and A are parallel, the divided electrode C3
...The display area C6, that is, the scales 21 to 50, does not allow light to pass through regardless of the state of the liquid crystal LC2 and becomes dark.

Furthermore, the display area formed by the divided electrodes C7 and C2, that is, the scales O to 20, allows light to pass through.

On the other hand, in order to darken the display area of scales 16 to 20, a voltage ``2'' is applied to the divided electrodes S1...S5 corresponding to this area, and a voltage 3`` is applied to the divided electrodes S6...StO.

As a result, the divided electrode C1' and the divided electrode S1...
・Voltage ■ is applied to the liquid crystal LC2 between StO.

-■ is applied and responds, and the divided electrode c2'b and the divided electrode S.

. . . Voltage 2■ is applied to the liquid crystal LC2 between 810 and responds.

The voltage applied to the liquid crystal LC2 between the residual divided electrode 02/director and the divided electrodes S1, .

Therefore, the display area of scales 0 to 15 becomes brighter, the area of scales 16 to 50 becomes darker, and the numerical value 15 is displayed.

Because of the above, the voltage applied to the electrodes requires a maximum voltage of 3 times the saturation voltage of the liquid crystal, and in addition, voltages V and 2 V are required, making the power supply circuit complicated. I wasn't in a good mood.

Further, in the region where voltages of 2V and 3V are applied, power is wasted, resulting in an increase in power consumption.

Moreover, the contrast of the regions to which the voltages V, 2V, and 3V are applied differs slightly, and uniform display is not performed.

In terms of its structure, it required four glass substrates and three polarizing plates, was floating, and caused errors in reading the scale depending on the viewing angle, which was undesirable.

Furthermore, alignment when combining these liquid crystal panels was complicated.

Therefore, the present invention provides a space between the first button and the second transparent substrate, and a space between the first button and the second transparent substrate.
A liquid crystal is interposed between a button and a third transparent substrate, and a thin liquid crystal display device sandwiched between two polarizing plates, which requires fewer lead wires, is driven at a low voltage to display an integrated value.
This eliminates the above-mentioned conventional drawbacks.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Figure 1 shows a bar graph meter that displays temperature, voltage, etc., and as shown in Figure 2, it consists of two polarizing plates A and B with polarization axes perpendicular to each other, and a first, second, and third polarizer. Three glass substrates constituting the transparent substrate G1. G2. G3 and the glass substrate G0. G2 button and glass substrate G2. Twisted nematic liquid crystal LC1, L interposed between G3
C2 is also configured.

L is a light source such as a fluorescent lamp. Glass substrate G1. G2. G
3 is for forming electrodes as shown in FIG.

A common electrode C8 is formed on the glass substrate G1, and divided electrodes C0...C5 constituting the first divided electrode are formed on the surface of the glass substrate G2 facing the liquid crystal LC1; are divided electrodes C'1...O constituting a second divided electrode having exactly the same shape as the divided electrodes C1...C6.
/, is formed.

Divided electrodes C1...C5 and divided electrodes 0/1...015
The lead wires are connected respectively.

On the glass substrate G3, divided electrodes S, .
- It is formed so as to face each of C10.

FIG. 4 shows the pulses applied to each electrode of the liquid crystal panel and the resulting pulses applied to the liquid crystals LC1 and LC2.

In the same figure, W. X, Y, and Z are pulses of the same waveform with a constant period and whose phases are shifted by a period.

1. The common electrode C6 is constantly supplied with pulses Y in the first column in the same figure, and the divided electrodes C1...05i- and the divided electrodes C
/1...0/.

In common, pulses w, x, and y are selectively supplied as shown in column 2 in the figure.

On the other hand, the divided electrodes S1...Sl. , pulses X and Z are selectively supplied as shown in column (2).

Due to the above pulses, the voltage O, the pulse (x, y) and the pulse (w, y) are selectively applied to the liquid crystal LC1, and the pulse (X, y) is selectively applied to the liquid crystal LC2.

Y), (Y, Z), voltage O, pulse (X, Z).

(W, X) and (W, Z) are selectively applied.

Therefore, we will briefly describe the case where the voltage applied to the liquid crystal LO1 is O.

When the applied voltage is 0, the liquid crystal LC1 becomes non-responsive, and the long axes of its molecules are twisted by 90 degrees.

On the other hand, at this time, the liquid crystal LC2 has pulses (X, Y), (Y
, Z) is selectively applied, the liquid crystal LC2 responds, and the long axis of its molecules is aligned in the direction of application of the electric field.

Therefore, the light that has passed through polarizing plate B passes through liquid crystal LC2 as it is, is twisted by 90 degrees by liquid crystal LC2, and is twisted by polarizing plate A.
pass through.

Therefore, among the divided electrodes C1 to C3, the display area facing the divided electrode to which the pulse Y has been applied becomes brighter and enters a single display state.

Next, a case will be described in which a pulse (x, y) is applied to the liquid crystal LC1.

The liquid crystal LC1 responds to the pulse (x, y).

On the other hand, at this time, the liquid crystal LC2 has a voltage O, a pulse (X'',
Z) is selectively applied.

First, when the voltage applied to the liquid crystal LC2 is O, the light that has passed through the polarizing plate B is twisted by 90 degrees by the liquid crystal LC2, passes through the liquid crystal LO1, and then passes through the polarizing plate A.

Therefore, among the divided electrodes S1...S1o, the display area corresponding to the divided electrode to which the pulse X has been applied becomes bright, and enters a - display state.

Next, when a pulse (X, Z) is applied to the liquid crystal LC2, the liquid crystal LC2 responds, and the light that has passed through the polarizing plate B passes through the liquid crystals LO2, LO, and is blocked by the polarizing plate A. Ru.

Therefore, among the divided electrodes S1...810, the display area corresponding to the divided electrode to which the pulse Z is applied becomes dark,
A different display state will occur.

Next, a case will be described in which a pulse (w, y) is applied to the liquid crystal LO1.

The liquid crystal LO1 responds by applying the pulse (w, y).

On the other hand, at this time, the liquid crystal LC2 has pulses (W, X), (W
, Z) is applied, and the liquid crystal LC2 also responds.

Therefore, the light that passed through the polarizing plate B is the liquid crystal LC2, LC1.
, and is blocked by the polarizing plate A.

Therefore, among the divided electrodes C1 to C3, the display area corresponding to the divided electrode to which the pulse W has been applied becomes dark and enters another display state.

FIG. 5 shows a circuit for supplying the pulses W...Z to each electrode.

In the figure, numbers 1 and 2 receive data on temperature, voltage, etc., and generate the 1st and 10th places by binary coded decimal output.

3 is a timing pulse generator, and its output terminal 3a
...3d, pulses W...Z are generated, respectively.

4 is a conversion circuit consisting of a gate circuit, etc., and its output terminals 4a...4j generate pulses Z and X as shown in FIG. 6 in accordance with the data from the data generation circuit 1, respectively. be.

5 is a control circuit consisting of a gate circuit, etc., which receives the output from the data generation circuit 2, and the 10th place of the data is 0.2.4.
, the output terminals 5a...5j are connected to terminal 4, respectively.
a... A pulse is generated from 4j, and the 10th position of the data is 1.
, 3, the output terminals 5a...5j are connected to the terminals 4j, respectively.
. . . generates pulses from 4a, and connects the output terminals 5a . . . 5j of the control circuit 5 to the divided electrodes S in FIG.
, . . . are connected to StO.

In this way, using the control circuit 5, the terminal 4 is
The connection relationship between a to 4j and terminals 5a to 5j is reversed because the divided electrodes S1...StO are wired in a zigzag pattern.

That is, the scale l~10.21~30, 41~50 is,
This is because the scales 11 to 20 and 31 to 40 are respectively displayed by the divided electrodes 810...S, contrary to the above, although they are displayed by the divided electrodes S1...S1o.

For example, when displaying scales 1 to 1O sequentially, as will be described later, in this order, the division electrodes S1...810,
The pulses X are sequentially supplied, and the scale 11~
20, the positional relationship of the divided electrodes S1...StO corresponding to this scale is reversed, so contrary to the above, the divided electrodes 810...Sl are sequentially displayed in the order of pulses We must continue to provide this.

The reason why the middle divided electrodes S1...S1o are connected in a zigzag manner is to prevent the wiring lines from crossing each other, and this is a commonly used technique in this field.

Reference numeral 6 denotes a conversion circuit consisting of a gate circuit, etc., which generates pulses X, Y, and W at output terminals 6a, . . . , and 6e, respectively, as shown in FIG. 7, according to data.

Connecting the output terminals 6a...6e of the conversion circuit 6 to (divided electrode 011- and divided electrode C'1)...(divided electrode 0.i- and divided electrode C',) in FIG. 2, respectively. It is.

Next, the operation will be explained.

For example, a case where 15 scales are displayed will be explained.

In this case, a pulse X is generated from the output terminals 4a . . . 4e of the conversion circuit 4, and a pulse Z is generated from the output terminals 4f .

On the other hand, due to the output of data 1 from the data generation circuit 2,
Pulses from terminals 4j...4a are generated at output terminals 5a...5j of control circuit 5, respectively, and are supplied to divided electrodes S1...810 in FIG. 2, respectively.

Then, the output terminal 6aKIri pulse Y of the conversion circuit 6 is
The output terminal 6b receives a pulse X, and the output terminals 6c, 6d, 6
At e, a pulse W is generated as shown in Fig. 7, and each of the pulses W is generated as shown in Fig.
(The divided electrode C6 button and the divided electrode C'5) are supplied.

Therefore, the voltage applied to the liquid crystal between the common electrode C8 and the divided electrode 01 becomes O, and as described above, the 10th scale corresponding to the divided electrode C1 is displayed brightly.

On the other hand, divided electrode C/2 and divided electrode S.

...The applied voltage between S7 becomes O, and this scale is displayed brightly, and the 15th scale is displayed brightly.

As described above, the integrated display is performed according to the data from the data generating circuits 1 and 2.

As described above, since pulses with the same waveform but different phases are selectively supplied to each electrode, it is only necessary to shift the phase of pulses of a fixed period and supply them, which simplifies the circuit configuration.

Further, as described above, when the duty of the pulse is set to k, the duty of the pulse applied to the liquid crystal becomes k.

Therefore, the voltage of this pulse ■. is the saturation voltage of the liquid crystal.
The setting is made so as to satisfy the following equation: yo2 = y2.

That is, the voltage of the pulse ■.

By setting the voltage to approximately 1.4 times the saturation voltage, you can obtain the same effective voltage value as if the saturation voltage was constantly applied. Looking at the power consumption, response speed button, and contrast, when the saturation voltage ■ is constantly applied, becomes the same as

Therefore, there is no need for wasted power consumption due to the constant application of voltages of 2V and 3V as in the past, resulting in low power consumption.
Moreover, a sufficient response speed button and uniform contrast can be obtained.

As mentioned above, setting the duty of the pulses w, x, y, and z to A is the most preferable because it requires the lowest voltage and has the fastest response speed compared to setting the duty to a smaller value. However, the present invention is not limited to this, and it is also possible to drive using a pulse with a smaller duty, for example, a pulse with a smaller duty.

That is, the above-mentioned pulses W and X are applied to four systems of pils having different phases in terms of duty.

It may be used in place of Y and Z and driven in exactly the same manner as above.

However, in this case, the duty of the voltage applied to the liquid crystal that should respond becomes electric, so unless the pulse voltage is set to twice the saturation voltage, the effective voltage value will be the same as if the saturation voltage was constantly applied. is not obtained.

Therefore, the duty of the pulse is most preferably k.

In the above embodiment, polarizing plates A and B having polarizing axes perpendicular to each other are used, but polarizing plates having polarizing axes parallel to each other may be used. In this case, the brightness and darkness of the display will be different from the above. is reversed.

In the above embodiment, data such as voltage and temperature are displayed using bar graphs, but the present invention is not limited to this, and for example, time such as seconds may be displayed.

In this case, for example, the common electrode is made circular, the first divided electrode and the second divided electrode are made into a fan shape obtained by dividing the circle into 12, and the third divided electrode is arranged in a zigzag manner to each of the second divided electrodes. Have the books face each other.

Then, in accordance with the second data from the clock device, a signal is supplied to each electrode in the same manner as in the above embodiment to display the integrated seconds.

As detailed above, the present invention includes a liquid crystal panel in which a liquid crystal is interposed between first and second transparent substrates and between a second button and a third transparent substrate, sandwiched between two polarizing plates, Pulses of the same waveform but different only in phase are selectively applied to each electrode of a liquid crystal display device in which divided electrodes formed on both sides of a second transparent substrate are commonly connected. Since the display state is made to differ between the display area where one of the liquid crystals is non-responsive and the display area where both of the liquid crystals are responsive, low-voltage driving is possible, low power consumption, and integration with a thin structure. Can be displayed.

Therefore, when reading, the scale can be read accurately even when viewed from an oblique direction.

Moreover, since the waveform of each pulse is the same, it is only necessary to supply pulses of a fixed period to each electrode with a phase shift.
This simplifies the circuit configuration.

Further, since the application time of the pulses applied within one cycle to the liquid crystals that should respond is the same, and the voltage applied to the liquid crystals that should not respond is O, completely uniform display can be performed.

In particular, when the duty of the constant period pulse is set to I, the application time within one period of the pulse applied to the liquid crystal to be responded is long, so that low electrode driving can be performed and the response speed is fast.

Furthermore, in order to commonly supply signals to the electrodes formed on both surfaces of the second transparent substrate, a common lead wire can be led out from the circuit board, and the number of lead wires can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an example of a liquid crystal display device of the present invention;
FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, FIG. 3 is a front view showing each of the glass substrates that constitute the liquid crystal panel in FIG. 1, and FIG. 4 shows the pulses supplied to each electrode, An explanatory diagram showing the pulses applied to the liquid crystal as a result, FIG. 5 is a block diagram showing an example of the circuit that generates the voltage shown in FIG. FIG. 8 is a sectional view showing an example of a conventional liquid crystal display device, and FIG. 9 is an explanatory view for explaining the operation of FIG. G1...First glass substrate, G2...
・Second glass substrate, G3...Third glass substrate, Co...Common electrode, C1 to C5...
・First divided electrode, 0/1 to 015...Second divided electrode, S1 to StO...Third divided electrode, L
Cl, LC2...Liquid crystal, A, B...Polarizing plate.

Claims (1)

[Claims] 1. A common electrode is formed on one surface of a first transparent substrate, a plurality of first divided electrodes are formed on one surface of a second transparent substrate facing the common electrode, and a plurality of first divided electrodes are formed on the other surface of the second transparent substrate. A second divided electrode is formed corresponding to each of the first divided electrodes, and each corresponding first divided electrode and second divided electrode are electrically connected, and one surface of the third transparent substrate is formed. A plurality of third divided electrodes are formed facing each of the second divided electrodes, and a button between the first transparent substrate and the second transparent substrate, and a liquid crystal is provided between the second transparent substrate and the third transparent substrate. A method for driving a liquid crystal display device in which a polarizing plate is provided opposite to each other surface of a first transparent substrate button and a third transparent substrate with at least four polarizers having the same waveform but different only in phase. A pulse generation circuit that generates a series of pulses is provided, one series of pulses is applied to the common electrode, and the above one series of pulses and the other two series of pulses are applied to the first divided electrode and the second divided electrode. is selectively applied to the third divided electrode, and a pulse button of one system of the other two pulse systems and a pulse of another system are selectively applied to the third divided electrode, and the common electrode and the first divided The area where the same system of pulses is applied to each of the electrodes and the area where the same system of pulses is applied to each of the second divided electrode and the third divided electrode are continuous on the same plane in one display state. A display area was formed, and different types of pulses were applied to each of the common electrode and the first divided electrode, and different types of pulses were applied to each of the second divided electrode and the third divided electrode. A method for driving a liquid crystal display device in which display regions in different display states are continuously formed on the same plane.