JPH07140442A - Method for driving ldc matrix panel - Google Patents

Abstract

PURPOSE:To reduce power consumption when a full surface is made inactive with an easy operation and a simple constitution. CONSTITUTION:When a control signal B is H, an output from an OR gate group 10, that from an OR gate 12 are H and a bias voltage VI is impressed to all common electrode. When the control signal B is also H, an output from an OR gate group 11 is H, and that from an AND gate 14 is L and the biased voltage VI is impressed to all segment electrode. Thus, an LDC matrix panel I made inactive on its full surface. In this case, since the impressed voltage VI is constant, no charged/discharged current flows to the equalizing capacitor, etc., of the LDC.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LCD matrix panel driving method for line-sequentially driving an LCD (liquid crystal) matrix panel.

[0002]

2. Description of the Related Art FIG. 2 is a diagram showing a configuration example of an LCD matrix panel drive circuit used in a conventional LCD matrix panel drive method. The LCD matrix panel drive circuit is a circuit that drives the LCD matrix panel 1. Although not shown, the LCD matrix panel 1 has a plurality of common electrodes arranged in the horizontal direction and a plurality of segment electrodes arranged on the opposite side of the electrodes in the vertical direction perpendicular to the electrodes. The LCD at a predetermined position is changed and displayed by the voltage selectively applied to both electrodes. The scan data generator 2 that constitutes a drive circuit is for generating scan data for scanning the common electrodes of the LCD matrix panel 1, and the scan data is held (latched) by the scan data holder 3. The bias power source selection unit 4 receives a plurality of levels of bias voltages V1, V2, V5 from the bias power source unit 5.
V6 is applied, a predetermined bias voltage is selected based on the scan data from the scan data holding unit 3, and this is selected on the LCD.
This is a circuit applied to the common electrode of the matrix panel 1.
The common side control unit of the LCD matrix panel 1 is configured by such elements. On the other hand, LCD
The segment side (data side) control section of the matrix panel 1 is composed of a display data generating section 6, a display data holding section 7, a bias voltage selecting section 8 and the bias power supply section 5. That is, the display data generated by the display data generation unit 6 is latched by the display data holding unit 7 and given to the bias power supply selection unit 8. Here, since the bias power supply unit 5 is supplied with the bias voltages V1, V3, V4 and V6 of a plurality of levels from the bias power supply unit 5, the predetermined bias voltage selected based on the display data is displayed on the LCD. It is adapted to be applied to the segment electrodes of the matrix panel 1. Note that the LCD generally deteriorates in characteristics when a DC voltage is applied. Therefore, in order to prevent this, an AC signal A is applied to the bias power source selecting units 4 and 8 via the signal line 9 to cause the LCD matrix panel 1 to have a DC constant voltage. Is not applied.

Next, a method of driving a conventional LCD matrix panel using the circuit of FIG. 2 will be described. Since the common side control unit performs line-sequential scanning, it supplies a bias voltage so that the common electrodes are sequentially lit one by one. Table 1 is a truth table showing the operation of the common side control unit. In the table, the symbol "H" is high level, "L" is low level, "V1", "V".
2 ”,“ V3 ”, and“ V4 ”represent bias voltages.

[Table 1] Table 2 is a truth table showing the operation of the segment side control unit, which operates in synchronization with the line scanning on the common side.

[Table 2] In addition, in the outputs V1 to V6 in Tables 1 and 2, V1>V2>
The relationship of V3>V4>V5> V6 is established.

In the circuit of FIG. 2, in the voltage averaging method, when the AC signal A is H, the common electrode is V1 and the segment electrode is V6, or when the AC signal A is L, the common electrode is When the segment side electrode becomes V1 at V6, the potential difference (| V1-V6 |) between the electrodes becomes high potential, and the LCD at the intersection of both electrodes is in the lighting selected state (corresponding to lighting). On the other hand, when the AC signal A is H, the common side electrode is V5 and the segment side electrode is V4 or V
6, when the common side electrode is V1 and the segment side electrode is V4, or when the AC signal A is L, the common side electrode is V2 and the segment side electrode is V3 or V1, and the common side When the electrode is V6 and the segment side electrode is V3, the potential difference (| V2
-V3 |, | V4-V5 |, | V1-V4 |, | V6-
V3 |, | V2-V1 |, | V5-V6 |) becomes low potential, and the LCD at the intersection of both electrodes remains in the non-lighting selected state (corresponding to non-lighting). Further, in the circuit of FIG. 2, when the entire panel surface is made inactive (non-lighting) when there is no display, there have conventionally been the following two methods. The first method is a method in which at least one of the scan data on the common side and the display data on the segment side is all data corresponding to inactivity (L in the examples of Tables 1 and 2). The second method is the inactive bias voltage (L
This is a method of adjusting the bias power supply unit 5 so that a voltage equal to or lower than the CD threshold value) is applied.

[0005]

However, in the conventional driving method of the LCD matrix panel, when the first method is adopted, the alternating voltage is applied to the LCD matrix panel 1 by the alternating signal A, so that the LCD Charge and discharge current flows through the equivalent capacitor of. In addition, a charge / discharge current also flows through a signal line that is connected to the common electrode and the segment electrode and that transmits a voltage in the active state or the inactive state to the common electrode and the segment electrode. As a result, there is a problem that power is consumed in the LCD matrix panel 1 and the signal lines connected to the common electrodes and the segment electrodes even when the LCD matrix panel 1 is in the inactive state. On the other hand, when the second method is adopted, it is necessary to change the voltage of the bias power supply unit 5, so that there is a problem that the circuit configuration of the bias power supply unit 5 becomes complicated and the cost required therefor increases. It was SUMMARY OF THE INVENTION The present invention solves, as problems that the above-mentioned prior art has, a charge / discharge current to an equivalent capacitor and a signal line of an LCD and an increase in cost due to a complicated circuit configuration of a bias power supply unit, and a simple operation. With the above configuration, a method for driving an LCD matrix panel is provided that reduces power consumption when the entire surface is deactivated.

[0006]

In order to solve the above problems, the present invention provides, for example, an LCD matrix panel (1).
The first LCD driving DC bias voltage (V1
Alternatively, by applying a plurality of LCD driving DC bias voltages (V1 to V6) including V6) and averaging the voltages, the L
In the LCD matrix panel driving method of line-sequentially driving the CD matrix panel, the following first, second and third steps are executed. In the first step, in the first period, the potential level of the first data signal (scan data) and the potential level of the first alternating signal (output of the OR gate 12) are set to the first LCD drive. A plurality of LCD driving DC bias voltages (V1, V2, V5, V6) including a DC bias voltage for use are output to each of the common electrodes, and a second data signal (display The potential level of the data) and the potential level of the second AC signal (output of the AND gate 14) are set to a plurality of LCD driving DC bias voltages (V1, V1) including the first LCD driving DC bias voltage.
3, V4, V6) is output to each of the segment electrodes. In the second step, an instruction signal (B) for deactivating the entire surface of the LCD matrix panel is provided in the second period. In the third step, in the second period, the potential level of the first data signal and the potential level of the first alternating signal are changed to the first LCD driving direct current in response to the instruction signal. The bias voltage is fixed to a third combination so that it is applied to all of the common electrodes substantially simultaneously, and the potential level of the second data signal and the potential level of the second alternating signal are set. , A fourth combination such that the first LCD driving DC bias voltage is applied to all of the segment electrodes substantially simultaneously.

[0007]

According to the present invention, in the first period, a predetermined LCD driving DC bias voltage is applied to the common electrode and the segment electrode by the first and second combinations,
Normal LCD matrix driving is performed. In the second period, when the instruction signal for deactivating the entire surface of the LCD matrix panel is input, the first LCD driving DC bias voltage is applied to all of the common electrodes and the segment electrodes, and the LCD Generation of charging / discharging current in the equivalent capacitor and the signal line is suppressed. Therefore, the above problem can be solved.

[0008]

First Embodiment FIG. 1 is a block diagram of an LCD matrix panel drive circuit used in a method for driving an LCD matrix panel according to a first embodiment of the present invention. It should be noted that elements common to the elements in the related art in FIG. 2 are denoted by common reference numerals. In this LCD matrix panel drive circuit, a new OR is provided between the scan data holding unit 3 and the bias power supply selecting unit 4 on the common side in FIG.
A gate group 10 is provided, and an OR gate group 11 is newly provided between the display data holding unit 7 and the bias power source selection unit 8 on the segment side, and an OR gate 12,
A signal input circuit including an inverter 13 and an AND gate 14 is added. Here, the signal A in the figure is an alternating signal, and the signal B is a control signal (instruction signal) which is a feature of this embodiment. The alternating signal A is logically ORed with the control signal B in the OR gate 12 to obtain the bias power source selection unit 4
And the inverted control signal B ^{− which} is inverted by the inverter 13 and is ANDed by the AND gate 14 and is given to the bias power source selection unit 8. Further, the control signal B is given to each OR gate which constitutes the OR gate groups 10 and 11.

Next, the driving method of the LCD matrix panel of the first embodiment using the circuit of FIG.
Will be described with reference to. First, in the common side control unit, when the control signal B is H (second period), the OR is performed regardless of the scan data (output of the scan data holding unit 3).
The output of the gate group 10 becomes H. Also, the OR gate 12
As for the output of the above, if the control signal B is H, it becomes H regardless of the alternating signal A. Therefore, it can be seen from Table 1 that the voltage applied to the common electrode is always V1.
On the other hand, in the segment side control section, when the control signal B is H, the output of the OR gate group 11 becomes H regardless of the display data (output of the display data holding section 7). Further, the output of the AND gate 14 becomes L regardless of the AC signal A if the control signal B is H. Therefore, it can be seen from Table 2 that the voltage applied to the segment electrodes is always V1. Thus, the control signal B is H
Then, since the bias voltage V1 having the same potential is applied to the common electrode and the segment electrode, the LCD matrix panel 1 is entirely inactive. At this time, since the applied voltage is constant, the charge / discharge current does not flow in the equivalent capacitor of the LCD. Further, the charging / discharging current does not flow in the signal line connected to the common electrode and the segment electrode and transmitting the voltage in the active state or the inactive state to the common electrode and the segment electrode.

When the control signal B is L (first period), the OR gate groups 10 and 11 allow the scanning data to pass therethrough, and the OR gate 12 and the AND gate 14 allow the alternating signal A to pass therethrough. , Normal line-sequential driving can be executed. In the first embodiment,
The OR gate groups 10 and 11 are provided between the data holding units 3 and 7 and the bias power supply selecting units 4 and 8, respectively, but OR is provided between the data generating units 2 and 6 and the data holding units 3 and 7, respectively. The gate groups 10 and 11 may be provided. Further, in the first embodiment, a signal obtained by logically adding (OR) the alternating signal A and the control signal B is input to the bias power source selection unit 4 on the common side, and the bias power source selection unit 8 on the segment side is input. the alternating signal a inverted control signal B ^- While are entering logical product (aND) signal, and inputs the logical product signal to the common side may enter a logical sum signal to the segment side. By doing so, the voltage V6 is applied to both the common electrode and the segment electrode.

Second Embodiment FIG. 3 is a block diagram of an LCD matrix panel drive circuit used in a method for driving an LCD matrix panel according to a second embodiment of the present invention. Elements common to those in FIG. 1 are designated by common reference numerals. In this LCD matrix panel drive circuit, OR gate groups 10 and 11 of FIG.
OR gate 12, inverter 13, and AND gate 14
Instead of this, switch circuit units 30 and 31 are provided on both the common side and the segment side. Each of the switch circuit units 30 and 31 is a circuit that switches the output to the common electrode and the segment electrode to the potential V7 side when the control signal B becomes H.

Next, a method of driving the LCD matrix panel of the second embodiment using the circuit of FIG. 3 will be described. When the control signal B is H (second period), the switch circuit unit 3
The individual switches forming 0 are switched to the potential V7 side. Therefore, the potential V7 is applied to the common electrode regardless of the output of the bias power source selection unit 4. In addition, the individual switches forming the switch circuit unit 31 also have the potential V
Since it is switched to the 7 side, the potential V7 is applied to the segment electrode irrespective of the output of the bias power source selection unit 8. As described above, when the control signal B is H, the common electrode and the segment electrode have the same potential, so that the entire LCD matrix panel 1 becomes inactive. Moreover, since the applied voltage is constant, no charging / discharging current flows. When the control signal B is L (first period), the switch circuit unit 3
0 and 31 do not operate, and normal line-sequential driving is performed. In the second embodiment, the switch circuit unit 30,
Reference numeral 31 can be composed of a thyristor, a MOS transistor, etc., and the potential V7 can also be supplied from the bias power supply unit 5.

[0013]

As described in detail above, according to the present invention, when the instruction signal for deactivating the entire surface of the LCD matrix panel is input in the second period, the common electrode and the segment electrode are changed. First for all
Since a DC bias voltage for LCD driving is applied, the potentials of the common electrode and the segment electrode become the same, and the entire surface is deactivated. At this time, since the common electrode and the segment electrode have a constant potential, the charge / discharge current in the equivalent capacitor of the LCD can be eliminated, and further,
It is also possible to eliminate the charge / discharge current in the signal line connected to the common electrode and the segment electrode and transmitting the voltage in the active state or the inactive state to the common electrode and the segment electrode. Therefore, when the entire surface is inactive, the power consumed by the LCD matrix panel and the signal lines connected to the common electrodes and the segment electrodes can be reduced. In addition, in the driving method of the present invention, the DC bias voltage for LCD driving used in the normal display operation is used as the voltage for deactivating the entire surface of the LCD matrix panel. An inexpensive LCD matrix panel drive circuit can be provided without complication.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an LCD matrix panel drive circuit used in a method for driving an LCD matrix panel according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an LCD matrix panel drive circuit used in a conventional LCD matrix panel drive method.

FIG. 3 is a configuration diagram of an LCD matrix panel drive circuit used in a method for driving an LCD matrix panel according to a second embodiment of the present invention.

[Explanation of symbols]

 1 LCD Matrix Panel 2 Scan Data Generation Section 3 Scan Data Storage Section 4, 8 Bias Power Supply Selection Section 5 Bias Power Supply Section 6 Display Data Generation Section 7 Display Data Storage Section 10, 11 OR Gate Group 12 OR Gate 13 Inverter 14 AND Gate 30 , 31 Switch circuit part A AC signal B Control signal V1 to V6 Bias voltage

Claims (1)

[Claims] 1. A first electrode for each of a plurality of common electrodes and segment electrodes arranged on an LCD matrix panel.
The plurality of liquid crystal driving DC bias voltages including the liquid crystal driving DC bias voltage are applied to average the voltage,
In a method for driving an LCD matrix panel, which drives the D matrix panel line-sequentially, the potential level of the first data signal and the potential level of the first alternating signal are set to the first liquid crystal driving in the first period. And a plurality of liquid crystal driving DC bias voltages including a DC bias voltage for driving are output to each of the common electrodes, and the potential level of the second data signal and the second AC signal are changed. A first step of setting the potential level to a second combination such that a plurality of liquid crystal driving DC bias voltages including the first liquid crystal driving DC bias voltage are output to each of the segment electrodes; A second step of providing an instruction signal for deactivating the entire surface of the LCD matrix panel in the second period; In response to the instruction signal, the potential level of the first data signal and the potential level of the first AC signal are substantially equal to the first liquid crystal driving DC bias voltage with respect to all of the common electrodes. And the potential level of the second data signal and the potential level of the second alternating signal are set to the first liquid crystal driving DC bias voltage. And a third step of fixing the fourth combination so that it is applied to all of the segment electrodes substantially at the same time.