JPH11149280A - Liquid crystal display - Google Patents

Abstract

(57) [Problem] To reduce an electric field radiated from a liquid crystal display device composed of two or more liquid crystal panels. SOLUTION: A liquid crystal panel having a plurality of scanning electrode rows and data electrode rows, a non-selection signal for disabling display and a selection signal for enabling display are generated, and the scanning electrode row is generated within a selection period. And a data electrode driving means for generating and applying the data voltage having the voltage level of the non-selection signal as a reference level, wherein the number of the liquid crystal panels is two or more. In a liquid crystal display device that is divided and displays an image by dividing an image for one frame on the divided liquid crystal display panel, the scan electrode driving unit may perform the same selection between the divided liquid crystal panels. Means for distributing the voltage level of the selection signal to each liquid crystal panel so that the selection signal does not have only the same voltage level within a period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which one liquid crystal panel is divided into a plurality of regions.
The present invention relates to a technique which is effective when applied to a liquid crystal display device which performs display by supplying driving power of liquid crystal independently for each of the divided areas.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device, in particular, a strip-shaped transparent electrode is provided on each of two glass substrates, and the two glass substrates are used to form an STN (Super Twisted).
d Nematic) A simple matrix liquid crystal panel sandwiching a liquid crystal and using pixels where pixels intersect each transparent electrode,
In a liquid crystal display device using a so-called STN liquid crystal panel, the number of scanning lines is 480 and the number of data lines is 640.
In realizing a so-called VGA display of a book, a so-called dual scan method is generally used, in which a display area is divided into upper and lower parts, that is, the number of scanning lines corresponding to each data line is reduced by half to 240 to perform VGA display. Met.

In the method of driving an STN liquid crystal panel of the dual scan system, a scanning line is sequentially selected one by one within one frame period, and a so-called line for applying a voltage to each pixel of the liquid crystal during this selection period. There are a sequential driving method and a so-called active driving method in which a voltage is applied to each pixel of the liquid crystal while simultaneously selecting a plurality of scanning lines.

In the line-sequential driving method, 0 V (zero volt) is set as a voltage to be applied when a scanning line is not selected (non-selection voltage), and a scanning line is selected from 28 V to 40 V and -28 V to -40 V. Voltage applied in case (selection voltage)
Alt Plesko driving method (also called smart addressing or HIFAS).
As a driving method widely used as a standard driving method, a set in which the non-selection voltage is 2 V and the selection voltage at this time is +30 V, the non-selection voltage is +28 V and the selection voltage at this time is 0 V There is a driving method of alternately outputting a set of frames for each frame and varying the voltage applied to the data lines based on each non-selection voltage.

The active driving method includes an all-line selecting method for selectively driving all the scanning lines within one frame period, and sequentially selecting about two to seven scanning lines sequentially during the selecting period. There has been a multiple line selection method in which a voltage is applied to each pixel of a corresponding scanning line during this selection period.

[0006]

SUMMARY OF THE INVENTION As a result of studying the above prior art, the present inventor has found the following problems. In a conventional liquid crystal display device using a simple matrix liquid crystal panel, except for a liquid crystal display device using an all-line selection method, each scanning line is selected, that is, a voltage is applied to each pixel for one frame. It will be about 1 to 7 times during the period. At this time, in the dual scan type liquid crystal display device which performs VGA display of 640 × 480 pixels, since the selection time of each scanning line is 1/240 in one frame period, a selection voltage of 15V to 40V is required. Was. Also,
In the conventional dual scan type liquid crystal display device,
A scanning line driving circuit for independently driving scanning lines is provided in each of the vertically divided display regions (liquid crystal panels). Each scanning line driving circuit is provided with a frame signal indicating one frame period and a direction of an electric field applied to the liquid crystal. An alternating signal for inverting, that is, instructing whether to output a positive or negative selection voltage to the scanning line is input to control the selection voltage and the non-selection voltage applied to each liquid crystal panel.

For this reason, the selection voltage of 15V to 40V is applied to each of the vertically divided liquid crystal panels at the same timing. Therefore, a simple matrix liquid crystal panel which does not divide the liquid crystal display panel, an active matrix liquid crystal panel, or the like is used. As compared with the matrix liquid crystal panel, there is a problem that an electric field change of 10 to 100 kHz at a position slightly (for example, 30 to 50 cm) away from the liquid crystal panel increases.

In particular, in recent years, there has been a concern that electromagnetic waves and electric fields radiated from information devices and home electric appliances will affect the human body, and it is important to suppress the radiation of these unnecessary electromagnetic waves and electric fields. .

An object of the present invention is to provide a technique capable of reducing an electric field radiated from a liquid crystal display device composed of two or more liquid crystal panels. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0010]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. (1) having a plurality of scanning electrode rows and data electrode rows;
A liquid crystal panel for displaying an image in accordance with the scanning voltage applied to the scanning electrodes and the data voltage applied to the data electrode rows; and sequentially selecting one or more scanning electrode rows from the scanning electrode rows. A selection signal consisting of two or more voltage levels for enabling display and a non-selection signal consisting of one or more voltage levels for disabling display by applying to a scanning electrode row not selected are generated within a selection period. A liquid crystal display device comprising: a scan electrode driving means for applying to the scan electrode row; and a data electrode drive means for generating the data voltage having a voltage level of the non-selection signal as a reference level and applying the data voltage to the data electrode row. The liquid crystal panel is divided into two or more,
In a liquid crystal display device which divides an image for one frame into the divided liquid crystal display panels to display an image, the scan electrode driving means includes: This is means for distributing the voltage level of the selection signal to each liquid crystal panel so that the selection signal does not have only the same voltage level.

(2) A liquid crystal panel having a plurality of scanning electrode rows and data electrode rows, and displaying an image in accordance with a scanning voltage applied to the scanning electrodes and a data voltage applied to the data electrode rows. And selecting one or more scan electrode rows from among the scan electrode rows sequentially and applying a selection signal consisting of two or more voltage levels that enable display and applying the signal to unselected scan electrode rows to disable display. Generating a non-selection signal including one or more voltage levels to be applied to the scan electrode row during a selection period; and generating the data voltage having the voltage level of the non-selection signal as a reference level. A liquid crystal display device having data electrode driving means for applying a voltage to the data electrode row, wherein the liquid crystal panel is divided into two or more, and an image for one frame is divided into the divided liquid crystal display panels. A first scan function generating means for generating a first scan function according to a selection period in accordance with a first orthogonal function set in advance, and -1 times the orthogonal function. And a second scan function generating means for generating a second scan function according to the selection period according to the second orthogonal function. The scan electrode driving means and the data electrode driving means Each of the liquid crystal panels has a different first and second
Is applied to each scan electrode row or data electrode row.

According to the above-described means (1), when the selection signals of different voltage levels are applied within the same period between the liquid crystal panels, that is, when the non-selection voltages are used as references, Since the electric field directions of the selection signal applied to the liquid crystal panel are opposite to each other, the fluctuation of the electric field due to the application of the selection voltage in the vicinity of the liquid crystal panel can be offset by the electric field in the opposite direction. The emitted electric field can be reduced.

According to the above-mentioned means (2), the first orthogonal function which is an orthogonal function expressing the line sequential driving method, the multiple line selection method and the all line selection driving method, and the second orthogonal function which is -1 times the first orthogonal function. The selection signal, the non-selection signal, and the data voltage selected and output according to the orthogonal function have a target relationship with respect to the reference potential of each signal, so that a liquid crystal panel driven in accordance with the first orthogonal function; In the liquid crystal panel driven by the second orthogonal function, the direction of the electric field of the selection signal applied to the liquid crystal panel can be reversed in the same manner as in (1) above, that is, in the vicinity of the liquid crystal panel. Fluctuations in the electric field due to the application of the selection voltage can be offset by the electric field in the opposite direction, so that the electric field radiated from the liquid crystal display device can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings together with embodiments (examples) of the invention. In all the drawings for describing the embodiments of the present invention, components having the same functions are denoted by the same reference numerals, and their repeated description will be omitted.

(Embodiment 1) FIG. 1 is a block diagram for explaining a schematic configuration of a liquid crystal display device according to Embodiment 1 of the present invention, wherein 101 is a liquid crystal controller, 102 is a liquid crystal panel, and 103a is upper data. A driver (data electrode driving means); 103b, a lower data driver (data electrode driving means); 104a, an upper scanning line driver (scanning electrode driving means); 104b, a lower scanning line driver (scanning electrode driving means); A scanning function generating means, 106 is an inverting means, 107 is a power supply circuit, and 108 is a display system main body.

In FIG. 1, a liquid crystal controller 101
Are the data drivers 103a and 103b, the scanning line drivers 104a and 104b, and the scanning function generator 105.
A well-known liquid crystal controller that supplies display data and various synchronization / control signals. This liquid crystal controller 1
01 is 12-bit parallel display data D0 to D1
1. A data latch clock CL2 used to capture display data, a line transfer clock CL1, which is a signal for one line, a head line clock FLM, and a display off control signal DISPOFF for controlling display on / off.
Is output.

The liquid crystal display panel 102 has, for example,
STN liquid crystal panel (upper liquid crystal panel 10) composed of 072 dots (1024 dots × 3 colors) and 384 dots vertically
2a, the lower liquid crystal panel 102b)
This is a dual scan type STN liquid crystal display panel that performs high-definition display of 024 × 768 dots, so-called XGA display.

The data drivers 103a and 103b are well-known data drivers for supplying data voltages to the upper liquid crystal panel 102a and the lower liquid crystal panel 102b, respectively. In the first embodiment, the number of outputs is 240. Data driver IC (Integrated C)
ircuit) are used. The details of the data drivers 103a and 103b will be described later.

The scanning line drivers 104a and 104b are well-known scanning line drivers for supplying a scanning voltage to the liquid crystal panel 102. In the first embodiment, the number of outputs is 19.
Four well-known scanning line driver ICs are used.

The scanning function generating means 105 counts the leading line clock FLM and the line transfer clock CL1 by a well-known counter (not shown) and, based on the counted values, two scanning functions based on an orthogonal function which is a Walsh function. A means for generating and outputting the signals W1 and W2. As this output pattern, two signals W1, W2
If the “High level” is “1” and the “Low level” is “0”, “00”, “01”, “10”,
There are four types of “11”. Here, when these four combinations are represented in decimal as 0, 1, 2, and 3, respectively, for example, the scanning functions W1 and W2 are 0132023.
101320...

The inverting means 106 comprises, for example, a well-known inverter circuit as shown in FIG.
The scan functions W1 and W2 input to the data driver 103b and the scan line driver 104b for driving the scan driver 02b are inverted.

The power supply circuit 107 is a circuit for supplying a drive voltage to each part of the liquid crystal display device according to the first embodiment, and is provided with an external power supply voltage Vc input from the display system main body 108.
c, VEE, the data voltage VY0 (for example, -5.
5V), VY1 (for example, 0 (zero) V), VY2
(For example, + 5.5V) and scanning voltages VX0 (for example, 0V), VXL (for example, -20V), VXH
(+ 20V) is generated and supplied. Also, the voltage VCON
Is a voltage for adjusting the output voltage of the power supply circuit 107. Further, a general logic voltage (Vcc = 5 volts, GND = 0 volt) is also supplied.

However, in the liquid crystal display device according to the first embodiment, according to the orthogonal function having a 6 × 6 square matrix as a selection matrix shown in the following equation 1, two times during one frame period determined by the first line clock FLM. Selection voltages are applied and two scanning lines (scanning electrode rows) within the same scanning period.
The scanning line driving based on the so-called multiple line selection method for driving the scanning lines of the liquid crystal panel 102 with a pattern for applying a selection voltage to the scanning lines of six scanning lines as one cycle is used.

[0024]

(Equation 1)

In Equation 1, ± 1 indicates a selected state, and 0 (zero) indicates a non-selected state.

Next, FIG. 6 is a diagram for explaining a selection voltage applied to each scanning line of the liquid crystal panel according to the first embodiment. Hereinafter, based on FIG. The operation of the liquid crystal display will be described. Note that FIG. 6A is a diagram illustrating a selection voltage in a first scanning period in a frame period, and FIG. 6B is a diagram illustrating a selection voltage in a second scanning period. FIG. 6C is a diagram showing a selection voltage in the third scanning period. In FIG. 6, the hatched portions indicate the liquid crystal pixels to which the selection voltage is applied in each scanning period, that is, the scanning lines, and the diagonal directions indicate the electric field directions of the selection voltage with reference to the non-selection voltage level. ing.

As shown in FIG. 6, in the liquid crystal display device according to the first embodiment, the upper and lower liquid crystal panels 102a, 102a, 1
02b scanning lines X1 to X384 for 384 rows
Are driven in units of two adjacent rows of blocks, and scanning for one frame is performed by 384 times of driving. At this time, the scanning voltage VXH or the scanning voltage VXL determined according to four predetermined scanning functions is applied to the two scanning lines driven at the same time. Furthermore, in the liquid crystal display device of the first embodiment, the data driver 103a and the scanning line driver 104a connected to the upper liquid crystal panel 102a, and the data driver 103b and the scanning line driver 104b connected to the lower liquid crystal panel 102b Here, the phases of the input scanning functions W1 and W2 are inverted by the inverting means 106. Thus, in the liquid crystal display device of the first embodiment, the electric field direction of the selection voltage applied to upper liquid crystal panel 102a and the selection voltage applied to lower liquid crystal panel 102b when the non-selection voltage level is used as a reference. The direction of the electric field is different from the direction of the electric field.

Therefore, in the liquid crystal display device of the first embodiment, as shown in FIGS. 6A to 6C, the upper liquid crystal panel based on the non-selection voltage level in the same scanning period The direction of the electric field of the selection voltage applied to the lower liquid crystal panel 102b can be different from the direction of the electric field of the selection voltage applied to the lower liquid crystal panel 102b.

That is, in the liquid crystal display device of the first embodiment, the scanning lines of the upper liquid crystal panel 102a are driven in accordance with the orthogonal function expressed by the equation (1). By driving the scanning lines of the lower liquid crystal panel 102b in accordance with the orthogonal function multiplied by 1, the directions of the electric fields of the selection voltages applied to the respective liquid crystal panels 120a and 120b are reversed. At this time, it goes without saying that the direction of the electric field of the data voltage output from the data drivers 103a and 103b also follows the orthogonal functions of Equations 1 and 2.

[0030]

(Equation 2)

FIG. 2 is a block diagram for explaining a schematic configuration of a scanning line driver IC constituting the scanning line driver according to the first embodiment, wherein 201 is a selector, 202 is a clock control circuit, and 203 is a scanning line. Selector, 204
Is a first level shifter, 205 is a second level shifter,
206 is a decoder, and 207 is a voltage selector.

In FIG. 2, the selector 201 outputs the output X
Based on a shift direction selection signal SHL for selecting the output direction of 1 to X192, that is, the shift direction of the output, which one of the two terminals DIO1 and DIO2 (hereinafter referred to as DIO1 / 2) is used as an input terminal and the other terminal is used as the input terminal. Is a well-known input / output switching means (IO selection means) for selecting whether or not is an output terminal. However, the signal (scan completion signal) output from the DIO1 / 2 terminal is the output X1 of the IC.
To X192 are completed, and the output of the outputs X1 to X192 is started based on the input signal.

The clock control circuit 202 is a known clock control circuit that generates a control signal for controlling the scanning line selector 203 based on the line transfer clock CL1, the leading line clock FLM, the shift direction selection signal SHL, and the scan completion signal. is there.

The scanning line selector 203 is, for example,
It has select circuits (not shown) for the number of scanning voltage output terminals (192), and generates 192 line select signals S1 to S192 based on the control output of the clock control circuit and outputs the signals to the first level shifter 204. I do. The line selection signals S1 to S192 correspond to 192 scanning lines on a one-to-one basis, and only two line selection signals corresponding to two simultaneously driven scanning lines are “High” during the same scanning period. Becomes Also, the scanning line selector 203
Is reset when the display-off control signal DISPOFF is “Low”, and all the line selection signals are set to “L”.
ow ”.

The first level shifter 204 outputs L of the line selection signals S1 to S192 and the scanning function signals W1 and W2.
The potential on the ow side (GND side) is changed to the scanning line driver 10.
4 is a well-known level shifter that level-shifts to VXL, which is a low-side potential of No. 4.

The second level shifter 205 has line selection signals S1 to S192 output from the first level shifter.
And the scanning function signals W1 and W2 on the High side (Vcc
This is a well-known level shifter that shifts the level of the scanning line driver 104 to VXH, which is the High side potential of the scanning line driver 104.

The decoder 206 outputs the level-shifted line selection signals S1 to S192 and the scanning function signals W1 and W2.
And the scanning voltages VXL, VX0, VX for driving the liquid crystal in accordance with the correspondence described later for each line selection signal.
H for selecting one level of H
3 outputs). However, in the first embodiment, as described later in detail, when the line selection signal is at a low level, a selection signal for selecting VX0 is output regardless of the scanning function output. On the other hand, when the line selection signal is at the High level, the scanning functions W1 and W2 are both High.
A selection signal for selecting VXH is output at the time of the h level, and the scanning function W1 is at the high level and the scanning function W2 is at the Lo level.
In the case of the w level, among the selected outputs, the odd-numbered outputs select VXH, and the even-numbered outputs select VXL. When the line selection signal is High
In the case of the level, the scanning functions W1 and W2 are both Lo.
At the time of w level, a selection signal for selecting VXL is output,
The scanning function W1 is at a low level and the scanning function W2 is at a high level.
In the case of the gh level, among the selected outputs, the odd-numbered outputs select VXL and the even-numbered outputs select VXH. That is, when the scanning function is inverted, the voltage selected by the selection signal is also inverted with reference to VX0.

The voltage selector 207 has one end connected to one of the outputs VXL, VX0 and VXH of the power supply circuit 107 and the other end connected to one scanning signal output terminal. A group of analog switches (for example, well-known transfer gates) is composed of the number of scanning signal output terminals (192). The control input of each analog switch corresponds to the selection signal on a one-to-one basis.
One of the scanning voltages VXL, VX0, VXH is output.

However, the scanning line drivers 104a and 104b according to the first embodiment are the same as the scanning line driver IC shown in FIG.
Are used respectively to constitute each scanning line driver.

Next, FIGS. 4 and 5 show diagrams for explaining the operation of the scanning line driver 104 according to the first embodiment. Hereinafter, the scanning line drivers 104a and 104b will be described based on FIGS. Will be described. In particular, FIG. 4 is a diagram for explaining the operation of the scanning line driver 104a that supplies a scanning voltage to the upper liquid crystal panel 102a, and FIG. 5 is a diagram for explaining the operation of the lower scanning line driver 104b.

The scanning line selector 203 performs the operations of S1 to S4 in FIG. 4 based on a control signal from the clock control circuit 202.
As shown in S384, a line selection signal for selecting two lines out of the 384 outputs is output at a timing synchronized with the line transfer clock. At this time, in the first embodiment, since the scanning lines are driven with six scanning lines as one period, as shown in FIG.
The signal group of the line selection signal shown in FIG. 6 is one pattern. Next, the first level shifter 204 and the second level shifter 205 sequentially convert the line selection signal output from the scan line selector 203 into a line selection signal of VXH on the High side and VXL on the Low side. At this time, the scanning functions W1 and W2 are also
Level shifted. The decoder 206 compares the input line selection signal with the scanning functions W1 and W2, and selects an analog switch (not shown) of the voltage selector 207 based on the comparison result.
In order, the scanning voltage corresponding to each input is output to the scanning line. The scanning voltages output to the respective scanning lines X0 to X384 at this time are indicated by X1 to X384 in FIG.

On the other hand, like the scanning line driver 104b,
When the inverted signals of the scanning functions W1 and W2 are input, the line selection signal input to the decoder 206 is
This is the same as the case described above. At this time, W1, W in FIG.
As shown in FIG. 2, since the values of the scan functions W1 and W2 are inverted, the decoder 206 outputs a scan voltage which is a target compared with FIG. 4 described above to the scan line based on the scan voltage VX0. The situation at this time is indicated by X385 in FIG.
~ X768.

As described above, by inverting the scanning functions W1 and W2, the scanning voltage output to the scanning line is changed between the upper liquid crystal panel 102a and the lower liquid crystal panel 102b on the opposite side with respect to the scanning voltage VX0. Voltage level. That is, in the upper liquid crystal panel 102a and the lower liquid crystal panel 102b, the direction of the electric field of the scanning voltage applied to each line is opposite when the scanning voltage VX0 is used as a reference.

FIG. 3 is a diagram for explaining a schematic configuration of the data driver ICs constituting the data drivers 103a and 103b according to the first embodiment, wherein 301 is a data rearrangement circuit, 302 is a shift register, and 303 is Reference numeral 1 denotes a latch circuit, 304 denotes a clock control circuit, 305 denotes a second latch circuit, 306 denotes a third latch circuit, 307 denotes an arithmetic circuit, 308 denotes a fourth latch circuit, and 309 denotes a liquid crystal driving circuit.

In FIG. 3, data rearranging circuit 301
Is a circuit that rearranges the arrangement order of the display data D0 to D11 input from the liquid crystal controller 101 based on the shift direction selection signal SHL and outputs it to the internal bus. For example, the circuit 2 corresponds to each signal line of the display data. It is composed of two known two-input AND circuits and one two-input OR circuit that uses the outputs of the two AND circuits as input signals.

The shift register 302 is a well-known shift register whose shift configuration can be changed by a shift direction selection signal SHL. For example, the shift register 302 receives the first data at the falling edge of a data latch clock CL2 for taking in display data.
And outputs a data capture signal to the latch circuit 303.
However, two terminal bars E of the shift register 302
/ IO1 and bar E / IO2 are well-known input / output terminals which operate as output terminals when one side is operating as an input terminal, and display data when operating as an output terminal. Outputs a latch completion clock indicating the completion of the above latch, and operates as a terminal for inputting a completion clock from the adjacent data driver IC when operating as an input terminal.

Four first latch circuits 303, that is, four
This is a well-known data latch circuit for four bits (4 bits), and display data D0 to D3 output to the internal bus in response to a data fetch signal from the shift register 302.
D4 to D7 and D8 to D11 of the latch circuit 303
Fetches and latches the display data of the internal bus to which is connected. Further, the first latch circuit 303 outputs the latched display data to the second latch circuit 305 and the third latch circuit 305, respectively.
To the latch circuit 306.

The clock control circuit 304 generates a second latch circuit 305 and a third latch circuit 306 based on the line transfer clock CL1 and the head line clock FLM.
And a data capture signal of the fourth latch circuit 308,
Also, it is a circuit that generates a selection signal of the arithmetic circuit 307 and outputs it to each corresponding circuit.

The second latch circuit 305 includes, for example, 2
It is composed of a well-known 40-bit latch circuit.
Is latched based on the data latch signal of the clock control circuit 304 and latched.

The third latch circuit 306 includes, for example,
A known latch circuit of 40 bits is a latch circuit composed of 12 stages, and the first latch circuit 303 or the second latch circuit
The data output from the latch circuit 305 is fetched and latched by the data fetch signal from the clock control circuit 304 for 12 lines. Further, the third latch circuit 306 outputs the touched data to the arithmetic circuit 30.
7 is output.

The arithmetic circuit 307 is composed of, for example, 240 well-known arithmetic circuits. First, two out of 12 bits input from the third latch circuit 306 in accordance with a selection signal from the clock control circuit 304. Select a bit. Next, the arithmetic circuit 307 compares the upper bit of the 2-bit data with the scan function W1 and the lower bit of the 2-bit data with the scan function W2, respectively, and checks the total number of matches. . Next, the arithmetic circuit 307
Generates a liquid crystal drive level selection signal for selecting one bit out of three bits from the total number, and outputs the signal to the fourth latch circuit 308. For example, when the total number is "0 (zero)", a signal for selecting data voltage VY0 is output, and when the total number is "1", a signal for selecting data voltage VY1 is output. In the case of "2", a signal for selecting the data voltage VY2 is output. FIG. 7 shows the relationship between the scan functions W1 and W2 and the data voltage at this time. As is apparent from FIG. 7, when the values of the scan functions W1 and W2 are inverted and input, Since the total number is the same as the case where “the total number before inverting the scanning function” is subtracted from 2, the data voltage V is included in the liquid crystal drive level selection signal output from the arithmetic circuit 307.
Only the signals for selecting Y0 and data voltage VY2 are interchanged.

The fourth latch circuit 308 includes, for example, 2
It is constituted by a well-known 40-bit latch circuit, and takes in and latches a liquid crystal drive level selection signal output from the arithmetic circuit 307 at the falling edge of the line transfer clock CL1 supplied via the clock control circuit 304. Further, the fourth latch circuit 308 converts the level of the latched liquid crystal drive level selection signal into a signal for driving the liquid crystal, and outputs this signal to the liquid crystal drive circuit 309.

The liquid crystal drive circuit 309 has, for example, one end connected to one of the outputs VY0, VY1 and VY2 of the power supply circuit 107, and the other end connected to an output to one data line. A group of three analog switches (for example, well-known transfer gates) is composed of the number of outputs to the data lines (240). The control input of each analog switch corresponds to the level selection signal corresponding to the liquid crystal drive level selection signal on a one-to-one basis. According to the output of the level selection signal, three output terminals are connected to the data lines.
One data voltage out of the two data voltages VY0, VY1, VY2 is output. However, the data voltage V shown in FIG.
Y0L, VY0R, VY1L, VY1R, VY2L, V
Y2R only indicates whether the data voltage is input to the liquid crystal driving circuit 309 from the Y1 side or the data voltage input from the Y240 side, and the input voltages are VY0 and VY0, respectively.
VY1 and VY2.

Next, the operation of the data driver according to the first embodiment will be described with reference to FIG.
02, first, the respective latch circuits constituting the first latch circuit 303 are sequentially selected, and one line of display data output to the internal bus by the data arrangement circuit 301 is stored in the first latch circuit. 303. The display data for one line output from the first latch circuit 303 is sequentially output to the third latch circuit 305 by the data capture signal output from the clock control circuit 304 to the second latch circuit 305 and the third latch circuit 306. The data is sequentially taken in from the first plane of the latch circuit 306. The display data captured by the third latch circuit 306 is sequentially selected from the 12-bit output from each plane by the arithmetic circuit 307 starting from the display data of the first row, two bits at a time. The total number of matches is calculated for each column, and the data voltage for driving the liquid crystal corresponding to the number of matches is output to the output terminal Y1 to the data line. Similarly, the data voltages for driving the liquid crystal up to the display data on the 240th row are output to the output terminals to the data lines.

Therefore, when the scanning functions W1 and W2 input to the scanning line driver 104b are inverted, the scanning functions W1 and W2 input to the data driver 103b corresponding to the scanning line driver 104b are also inverted and input. Thus, without changing the effective value of the driving voltage of the liquid crystal applied to each pixel of the liquid crystal panel 102, the electric field direction of the selection voltage in the upper liquid crystal panel 102a and the lower liquid crystal panel 102b, that is, the non-selection voltage The electric field direction of the selected voltage level based on the level can be reversed.

As a result, the electric fields radiated from the upper liquid crystal panel 102a and the lower liquid crystal panel 102b, respectively, are canceled by the electric fields in opposite directions, so that the amount can be reduced.

As described above, in the liquid crystal display device according to the first embodiment, the data driver 103a and the scanning line driver 104a connected to the upper liquid crystal panel 102a.
Has a scanning function W according to the orthogonal functions shown in Equations 1 and 2.
1 and W2 as they are, while the lower liquid crystal panel 10
The data driver 103a and the scanning line driver 104a connected to the scanning circuit 2b are supplied with the scanning functions W1 and W2 obtained by inverting the phases of the scanning functions W1 and W2 by the inverting means 106, thereby setting the scanning voltage VX0 as a reference. In this case, the direction of the electric field of the selection voltage applied to the upper liquid crystal panel 102a is opposite to the direction of the electric field of the selection voltage applied to the lower liquid crystal panel 102b.

Therefore, in the liquid crystal display device of the first embodiment, the upper liquid crystal panel 102a and the lower liquid crystal panel 102b
Since the electric fields respectively radiated from and are canceled by the opposite electric field, the amount can be reduced.

However, in the liquid crystal display device of the first embodiment, the scanning line driving based on the multiple line selection method in which the number of scanning lines to be selected at the same time is two is used.
The present invention is not limited to this, and it is needless to say that the present invention is applicable to a scanning line driving method based on a multiple line selection method including an all line selection method in which the number of simultaneously selected scanning lines is all lines.

However, as shown in the first embodiment, the effect of reducing the electric field radiated from the liquid crystal panel 102 in response to the application of the selection voltage to the scanning line is as follows.
This is particularly effective in a scanning line driven liquid crystal display device based on a multiple line selection method in which the number of scanning lines to be simultaneously selected to be V or more is 4 lines or less.

On the other hand, in the case of the multiple line selection method in which the number of simultaneously selected scanning lines is large, including the all line selection method in which the number of simultaneously selected scanning lines is all lines, the data voltage applied to the data line In this case, the effect of reducing the electric field radiated from the liquid crystal panel 102 with the application of the data voltage to the data lines (data electrode rows) is obtained.

(Embodiment 2) FIG. 8 is a block diagram for explaining a schematic configuration of a liquid crystal display device according to Embodiment 2 of the present invention, in which reference numeral 701 denotes a liquid crystal controller, and 702a and 702b.
703a, 7 are data drivers (scan electrode driving means)
03b, a scanning line driver (scanning electrode driving means);
Indicates a power supply circuit. However, the liquid crystal display device of the second embodiment is a so-called HIFAS drive type simple matrix liquid crystal display device in which a selection voltage is applied to one scanning line during one scanning period. In the second embodiment, only the parts that are the same as the first embodiment described above will be described.

In FIG. 8, the liquid crystal controller 701
Is a well-known liquid crystal controller that supplies display data and various synchronization / control signals to the data drivers 702a and 702b and the scanning line drivers 703a and 703b. The liquid crystal controller 701 includes 12-bit parallel display data D0 to D11, a data latch clock CL2 used to capture display data, a line transfer clock CL1 that is a signal for one line, a head line clock FLM, and display on / off control. , And an alternating signal M which is a control signal for changing the direction of the electric field of the selection voltage applied to each pixel of the liquid crystal panel 102.

The data drivers 702a and 702b are well-known HIFAS driving data drivers that supply data voltages to the upper liquid crystal panel 102a and the lower liquid crystal panel 102b, respectively.

The scanning line drivers 703a and 703b are a well-known HIFAS for supplying a scanning voltage to the liquid crystal panel 102.
It is a known scanning line driver for driving.

The power supply circuit 107 is a circuit for supplying a drive voltage to each section of the liquid crystal display device according to the first embodiment, and is provided with an external power supply voltage Vc input from the display system body 108.
c, VEE, the data voltage VY1 (for example, 5.5)
V), VY2 (for example, -5.5V) and scanning voltage VX0 (for example, + 2.5V), VXL (-32.5V).
V), VXH (for example, +37.5 V).

Next, FIG. 9 is a diagram for explaining a selection voltage applied to each scanning line of the liquid crystal panel according to the second embodiment. Hereinafter, based on FIG. The operation of the liquid crystal display will be described. Note that FIG. 9A is a diagram illustrating a selection voltage in a first scanning period in an arbitrary frame period, and FIG. 9B is a diagram illustrating a selection voltage in a second scanning period. FIG. 9C is a diagram showing the selection voltage in the third scanning period. In FIG. 9, the hatched portions indicate the liquid crystal pixels to which the selection voltage is applied in each scanning period, that is, the scanning lines, and the diagonal lines indicate the electric field direction of the selection voltage with reference to the non-selection voltage level. ing.

As shown in FIG. 6, in the liquid crystal display device of the first embodiment, upper and lower liquid crystal panels 102a, 102a, 1
02b scanning lines X1 to X384 for 384 rows
Are driven one row at a time, and one drive is performed by 384 times.
Scanning for a frame is performed. At this time, the scanning voltage VXH or the scanning voltage VXL determined according to the AC signal M is applied to the driven scanning line. Furthermore, in the liquid crystal display device of the second embodiment, the data driver 702a and the scanning line driver 703a connected to the upper liquid crystal panel 102a, and the data driver 702b and the scanning line driver 703b connected to the lower liquid crystal panel 102b Here, the phase of the input AC signal M is inverted by the inversion means 106. Accordingly, in the liquid crystal display device of the second embodiment, the direction of the electric field of the selection voltage applied to upper liquid crystal panel 102a with respect to the non-selection voltage level and the lower liquid crystal panel 102b
The electric field directions are different from the electric field directions of the selection voltage applied to the respective elements.

Therefore, in the liquid crystal display device of the second embodiment, as shown in FIGS. 9A to 9C, the upper liquid crystal panel based on the non-selection voltage level in the same scanning period The direction of the electric field of the selection voltage applied to the lower liquid crystal panel 102b can be different from the direction of the electric field of the selection voltage applied to the lower liquid crystal panel 102b.

As a result, in the liquid crystal display device of the second embodiment, the upper liquid crystal panel 102a and the lower liquid crystal panel 102
Since the electric fields respectively radiated from b and b are canceled by the electric field in the opposite direction, the amount can be reduced.

Further, in the liquid crystal display device of the first embodiment, the scanning lines of upper liquid crystal panel 102a are driven in accordance with an orthogonal matrix having a diagonal component of 1, and in accordance with an orthogonal matrix obtained by multiplying the orthogonal matrix by -1. Side liquid crystal panel 102b
Of the liquid crystal panel 120 by driving the scanning lines of
The electric field directions of the selection voltages applied to the a and 120b are opposite directions. At this time, the data driver 702
a, the electric field direction of the data voltage output from 702b is also
It goes without saying that each orthogonal matrix is followed.

In this embodiment, the horizontal 102
A description has been given of a dual scan type liquid crystal display device which uses two liquid crystal panels 102a and 102b of 4, 384 dots in height and arranges the liquid crystal panels 102a and 102b vertically to display an image for one frame. It is needless to say that the present invention is not limited to this, and it is needless to say that the present invention can be applied to a liquid crystal display device in which four liquid crystal panels are arranged vertically, horizontally, two by two, and an image for one frame is displayed.

In the liquid crystal display device according to the present embodiment, as a means for generating a function of -1 times the orthogonal function, the scanning function is inverted by the inverting means without using a dedicated means. However, it goes without saying that the calculation may be performed using a dedicated means. As described above, the invention made by the inventor has been specifically described based on the embodiment of the present invention. However, the present invention is not limited to the embodiment of the invention, and does not depart from the gist of the invention. It goes without saying that various changes can be made in.

[0074]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows. An electric field radiated from a liquid crystal display device including two or more liquid crystal panels can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a block diagram for explaining a schematic configuration of a scanning line driver IC constituting the scanning line driver according to the first embodiment;

FIG. 3 is a diagram for explaining a schematic configuration of a data driver IC constituting the data driver according to the first embodiment;

FIG. 4 is a diagram for explaining an operation of the scanning line driver according to the first embodiment;

FIG. 5 is a diagram for explaining the operation of the scanning line driver according to the first embodiment;

FIG. 6 is a diagram illustrating a selection voltage applied to each scanning line of the liquid crystal panel according to the first embodiment.

FIG. 7 is a diagram for explaining a relationship between scanning functions W1 and W2 and a data voltage in the liquid crystal panel of the first embodiment.

FIG. 8 is a block diagram illustrating a schematic configuration of a liquid crystal display device according to a second embodiment.

FIG. 9 is a diagram illustrating a selection voltage applied to each scanning line of the liquid crystal panel according to the second embodiment.

[Description of Signs] 101: liquid crystal controller, 102: liquid crystal panel, 10
3a: Upper data driver (data electrode driving means), 1
03b lower data driver (data electrode driving means);
104a: Upper scanning line driver (scanning electrode driving means)
104b: lower scanning line driver (scanning electrode driving means)
105: scanning function generating means, 106: inverting means, 107
.. Power supply circuit, 108 display system body, 201 selector, 202 clock control circuit, 203 scanning line selector, 204 first level shifter, 205 second
, A decoder, 207, a voltage selector, 301, a data rearranging circuit, 302, a shift register, 303, a first latch circuit, 304, a clock control circuit, 305, a second latch circuit, 306, a third Latch circuit, 307 arithmetic circuit, 308 fourth latch circuit, 309 liquid crystal drive circuit, 701 liquid crystal controller, 702a, 702b data driver, 703a,
703b: scanning line driver; 704: power supply circuit.

[Procedure amendment]

[Submission date] March 1, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008] In particular, in recent years, it is possible to suppress the radiation of unwanted electromagnetic waves and electric field that is emitted from the information devices and home appliances, etc. has become important.

Claims (8)

[Claims] 1. A liquid crystal panel having a plurality of scan electrode rows and data electrode rows, and displaying an image in accordance with a scan voltage applied to the scan electrodes and a data voltage applied to the data electrode rows. A non-selection signal comprising one or more voltage levels applied to unselected scan electrode rows to disable display and one or more scan electrode rows from the scan electrode rows are sequentially selected to enable display. Generating a selection signal having two or more voltage levels to be applied to the scan electrode array during a selection period; and generating the data voltage having the voltage level of the non-selection signal as a reference level. A liquid crystal display device having data electrode driving means for applying data to the data electrode row, wherein the liquid crystal panel is divided into two or more, and an image for one frame is divided into the divided liquid crystal display panels. hand In a liquid crystal display device that performs image display, the scan electrode driving unit includes: a liquid crystal display device that controls the liquid crystal panels so that the selection signal does not reach only the same voltage level within the same selection period between the divided liquid crystal panels. A liquid crystal display device, which is means for distributing a voltage level of a selection signal. 2. The liquid crystal display device according to claim 1, wherein the scan electrode driving means is configured to prevent the voltage levels of the selection signals of the adjacent liquid crystal panels from being the same in the same selection period. A liquid crystal display device as means for distributing the voltage level of the selection signal. 3. The liquid crystal display device according to claim 2, wherein the scanning electrode driving means supplies a selection signal to two scanning electrode rows for each liquid crystal panel within the same selection period. A liquid crystal display device, comprising: 4. The liquid crystal display device according to claim 1, wherein an output voltage level of said scan driver and said data driver during a selection period according to a preset orthogonal function. Means for generating a control signal for controlling the control signal, and inverting means for inverting the phase of the control signal, wherein the scan electrode driving means and the data electrode driving means are based on the control signal and the inverted control signal. A liquid crystal display device for driving the scanning electrode rows and the data electrode rows, respectively. 5. The liquid crystal display device according to claim 1, wherein said scan electrode driving means generates a selection signal of a first voltage level and a second voltage level. And a means for generating a non-selection signal of a third voltage level. 6. The liquid crystal display device according to claim 5, wherein said scanning electrode driving means generates a non-selection signal of a fourth voltage level and a fifth voltage level, and said first voltage level. And a means for applying a set of the select signal of the second voltage level and the set of the select signal of the second voltage level and a set of the non-selective signal of the fifth voltage level to the scan electrode row. A liquid crystal display device comprising: 7. The liquid crystal display device according to claim 6, wherein the first voltage level and the fifth voltage level, and the second voltage level and the fourth voltage level are respectively the same. A liquid crystal display device having a voltage level. 8. A liquid crystal panel having a plurality of scanning electrode rows and data electrode rows, and displaying an image according to a scanning voltage applied to the scanning electrodes and a data voltage applied to the data electrode rows. One or more scan electrode rows are sequentially selected from the scan electrode rows to enable display, and a selection signal consisting of two or more voltage levels is applied to the unselected scan electrode rows to invalidate the display. A scan electrode driving unit configured to generate a non-selection signal including one or more voltage levels and to apply the non-selection signal to the scan electrode row within a selection period; A liquid crystal display device having data electrode driving means for applying data to said data electrode rows, wherein said liquid crystal panel is divided into two or more, and an image for one frame is divided into said divided liquid crystal display panels. Picture In a liquid crystal display device for displaying an image, a first scanning function generating means for generating a first scanning function according to a selection period according to a first orthogonal function set in advance, and -1 times the orthogonal function. A second generating a second scanning function according to the selection period according to the second orthogonal function;
Scanning function generating means, wherein the scanning electrode driving means and the data electrode driving means respectively provide the divided liquid crystal panels with a selection signal corresponding to the different first and second scanning functions. A liquid crystal display device wherein a selection signal and a data voltage are applied to each scanning electrode row or data electrode row.