JPS6019196A - Method and apparatus for driving liquid crystal display - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a driving method for driving each pixel in a time division manner in a liquid crystal display device in which a plurality of scanning signal lines and a plurality of display signal lines are arranged in an intersecting manner and a display pixel is formed at each intersection. Regarding the device, the display surface area is increased.

This is to improve display unevenness that tends to occur with conventional driving methods as the number of display pixels increases.

Conventional driving methods of this type include those shown in FIGS. 1 to 12. 1 to 3 show the principle of the driving method. In FIG. 1, Xi, X2, X3 are display signal lines, Yr, Y2, . Y3 is a scanning signal line,
The white circle at the intersection of the display signal line and the scanning signal line indicates the selected pixel,
Black circles are non-selected pixels, eXl, eX2, etc. are voltage waveforms applied to the respective signal lines, ■0 is the reference voltage, vy+v
o is a scanning voltage, vo+vx is a non-selection voltage, and vo-vx is a selection voltage. FIG. 2 shows an example of a selection voltage waveform applied to a selected pixel, which is a drive voltage waveform applied to a display pixel at the intersection of the scanning signal line Y1 and the display signal line X1. FIG. 3 is an example of a non-selection voltage waveform applied to a non-selected pixel, which is a drive voltage waveform applied to a display pixel at the intersection of the scanning signal line Y1 and the display signal line X2.

Next, the operation will be explained. In the first stage of scanning,
A scanning voltage vo+vy appears on the scanning signal line Y1, and a scanning voltage vo+vy appears on the scanning signal line Y2. Both Y3 remain at the reference voltage VO. This means that the scanning signal line Y1 has been selected. Among the display pixels on the scanning signal line Yl, the one at the intersection with the display signal line X1 is the selected pixel, and the one on the display signal line X2. Since the pixel at the intersection of X3 is a non-selected pixel, the selection voltage vo-vx is applied to the display signal line XI, and the display signal line X2. A non-selection voltage vo+vx is applied to X3. Since the difference between the voltage of the scanning signal line and the voltage of the display signal line is applied to each display pixel, the voltage vy+vx is applied to the intersection of signal lines X1 and Yl, and the voltage vy+vx is applied to the intersection of signal lines X2 and Yl and X3 and Yl. is the voltage vy-vx
is applied.

Also, at this time, the scanning signal line y2. Since the voltage of Y3 is VO, the signal line Y2. A voltage of vX or -vX is applied to the display pixel on Y3. In the second stage of scanning, a scanning voltage appears on the scanning signal line Y2, the above operation is performed on the signal line Y2, and the same operation is repeated for each scanning line in the pot stage to complete one scanning period.

The important point here is that the voltage response of the liquid crystal does not depend on the polarity of the applied voltage, but only on its absolute value.
As mentioned above, when the scanning voltage is on the scanning signal line where the display pixel exists, the voltage applied to the display pixel during one scanning period is vy + vx for the selected pixel, and v y - v x for the non-selected pixel. ', and during the other periods, the voltage is IVXI, and the voltage applied to the selected pixels becomes higher than the voltage applied to the non-selected pixels on average, and a display appears. FIG. 2 shows the difference between eYl and eXl during one scanning period, and shows how the above selection voltage waveform is applied to the intersection of signal lines X1 and Yl. FIG. 3 shows the difference between eYl and eX2 during the same <1'' scanning period, and shows how the non-selection voltage waveform is applied to the intersection of signal lines X2 and Yl.

The above is an explanation of the principle of time-division driving of liquid crystals. However, if the above operation is simply repeated, as is clear from Figures 2 and 3, when the applied voltage is averaged over time, it does not become zero and becomes DC. Ingredients remain. However, driving liquid crystals with direct current has a significant impact on their lifespan and degrades display quality, so further improvements are needed in practice.

Two conventional methods for removing residual DC components will be described below.

Figure 4 is an example of the display image purple matrix and display pattern,
I, X2. -, Xi, -, Xn are display signal lines, Yl, Y
2. -, Yj, -, Ym are scanning signal lines, white circles are selected pixels, and black circles are non-selected pixels.

The display pixels on the display signal line X(i-1) are selected pixels.
This is an example of a driving waveform according to a practical conventional method. Fifth
Figure fan, (bl, (C1 is the scanning signal line Y
1. Y2. Scanning signal voltages eY1 and e applied to Y3
The waveforms of Y2 and eY3 are shown in Fig. 6(a), fbl
, , fcl are display signal lines X(i-1), respectively.

Display signal voltage eX applied to Xi,X (i+1)
(i-1), eXi, eX (i+1). FIG. 7 1al, <bl, (cl is an example of the drive voltage waveform applied to the display pixel as the difference between the scanning signal voltage and the display signal voltage, eYl −eX (i-1), eYl−
Voltages eXi and eYl -eX (i -1-1) are applied to the display pixels located at the intersections of the respective corresponding signal lines. Figure (a), (eYl-eX of bl
(i-1) and eYl-eXi are selection voltage waveforms, the same figure (C
1 eYl -eX (i+1) is a non-selection voltage waveform. In FIGS. 5 to 7, τ represents one stage, that is, one scanning selection period, and TI and T2 are the number of scanning lines m.
It represents the product of t and t, that is, one scanning period. In the figure, during the scanning period Tl, the potential ■5 corresponds to the reference potential ■0 in FIG. 1, vi is the scanning voltage vy + vo, V4 is the non-selection voltage VO + ■ corresponds to each. During the scanning period T2, ■2 corresponds to the reference potential ■0 in FIG. 1, and ■6 corresponds to the scanning voltage ■
At Y10, V3 becomes the non-selection voltage V O + V X, v
l corresponds to selection voltages vo-vx, respectively.

That is, in the T I period and the T2 period, the polarities of all voltages with respect to the reference potential are reversed. In this way, as is clear from the respective drive voltage waveforms in FIG. 7, the voltage applied to the liquid crystal during two scanning periods, that is, the period of TI+72, becomes a complete AC signal, thereby preventing the deterioration of the display quality of the liquid crystal. be able to.

A second practical conventional method for driving with an AC signal is shown in FIGS. 8-10. Figure 8(a),
(b) and (C) are the scanning signal voltage eY1, respectively.

The waveform of e Y 2 * e Y 3 is shown in Figure 9 (a
l, (b), TO) are the display signal voltage eX(
i1), eXi.

This is the waveform of eX(i+1). Figure 10 (al, (b)
).

(C) is an example of the drive voltage waveform applied to the display pixel as the difference between the scanning signal voltage and the display signal voltage, and as in FIG. 7,
eYl −eX (, i 1) in (a) and (b) of the same figure
and eYl, -eXi are the selection voltage waveforms, and eY in the same figure (C)
leX(i+l) is a non-selection voltage waveform. 5 represents one stage, that is, one scanning line selection period, and T represents one scanning period, which is the same as in FIGS. 5 to 7. While the first conventional method described above completes AC driving in two scanning periods, the second conventional method completes AC driving within one stage.

That is, in FIG. 8, in the first half of each stage, the potential v
5 is the reference potential VO in FIG. 1, and Vl is the scanning voltage vo+v.
y, and in the latter half, the polarity is reversed and v2 becomes the reference potential V
0, and v6 becomes the scanning voltage ■0+VY. The display signal voltage in Fig. 9 is also similar, and in the first half of each stage, v5 is
o, ■4 corresponds to the non-selection voltage vo+vx, V6 corresponds to the selection voltage vo-vx, and in the latter half, the polarity is reversed and V2 corresponds to ■o
, v3 is the non-selection voltage VO + VX, and ■1 is the selection voltage v
Compatible with ovx.

FIG. 11 shows a circuit for implementing the conventional method, in which 1 is a display pixel, Yl, Y2 . ... are scanning signal lines, Xl, X2
．． ... is a display signal line, and 2 is a scanning signal line Yl.

Y2. Y drive circuit that drives..., 3 is the display signal line X
I, X2. 4 is a control circuit that controls the Y drive circuit 2 and the X drive circuit 3, 5 is a display data line that sends display data from the control circuit 4 to the X drive circuit 3, and 6 is a control circuit. 4 is a scanning data line that sends scanning data to the Y drive circuit 2; 7 is a Cronk line; 8 is a strobe line; 9
11 is a frequency dividing circuit that divides the signal frequency of the strobe line 8 by 1/(2Xm), 10 is a waveform shaping circuit that shapes the signal of the strobe line 8 into a square wave with a duty ratio of 50%, and 11 is a frequency dividing circuit 9. A switch 12 selects the output from the waveform shaping circuit 10 and the output from the waveform shaping circuit 10. This is a polarity signal line that is supplied to the X drive circuit 3. 12th
Figures (a) to (d) illustrate important signals flowing through these signal lines, and CLOCK is clock 1.
Izumi 7.5 TROBE is strobe line 8, I'OLE I
For example, the output of the frequency divider circuit 9, POLE 2 is the waveform shaping circuit 10.
This is the voltage waveform of the output.

In such a circuit configuration, the X drive circuit 2 and the X drive circuit 3 have built-in shift registers, and the CLOCK
Accordingly, display data and scanning data are sent to the drive circuits 2 and 3, respectively, and when the data for one stage is lined up, 5TPOBE occurs, and the next STI? The above data is held in the shift registers of the redrive circuits 2 and 3 until OBE. Based on the held data, the X drive circuit 2 and the X drive circuit 3 set the scanning voltage 2 selection voltage and non-selection voltage with positive polarity if the data on the polarity signal line 12 is "1", and with negative polarity if it is 0. The pulse interval τ of 5TROBH corresponds to the one scanning line selection time τ in FIGS. , by using its output POLEI as a polarity signal, the first conventional method can be realized to complete AC drive in two scanning periods.On the other hand, the period of the waveform shaping circuit 10 matches τ, and the waveform shaping circuit 10 has a polarity of 1. Since "0" appears at equal intervals, if the output POLE 2 is used as a polarity signal, the second conventional method of completing AC drive in the I stage can be realized.

The conventional driving method for a liquid crystal display device is as described above.
Various problems have arisen as the display area becomes larger and the number of scanning lines increases. The reason for this is that the display pixel 1 in FIG. 11 is electrically a capacitive load, and the scanning signal line Y1. Y2.・
... and display signal lines XI, X2, ... are ideal conductors (and have a finite electrical resistance. Therefore, from the perspective of and the capacitance are connected in series to drive a load,
It is a well-known fact that when such a load is driven with AC, the voltage actually applied to the capacitance part, that is, the display pixel 1, depends on the frequency of the drive signal, and the higher the frequency, the lower the applied voltage. be. Increasing the display area inevitably brings about an increase in the resistance of the signal line, and the effect of the frequency dependence described above becomes thicker.On the other hand, the scanning period T is set at a certain time so that the human eye does not notice flickering. The selection time τ for one scanning line becomes shorter in inverse proportion to the increase in the number of scanning lines, pushing the frequency component of the drive signal higher.Also, as is clear from the principle, the selection voltage The difference between the voltage and the non-selection voltage appears only during the period in which the scanning line in which the display pixel exists is selected, and does not occur in other periods.

Therefore, in terms of effective value, it is natural that the above difference becomes smaller as the number of scanning lines increases.

If we first consider the first conventional method with these things in mind, it will be seen that the frequency components of the drive signal vary greatly depending on the display pattern, as is clear from FIG. Specifically, for display pixels on a column with a high spatial frequency of the display pattern, such as X(i-1) in FIG. The voltage drop is small in the display pixels on the column where the spatial frequency of the display pattern is low, such as Xi, X (i+1). Such a difference in applied voltage appears as a difference in shading of a display pattern, resulting in a serious defect in display quality.

Next, in the second conventional method, as is clear from FIG. 10, the frequency of the polar signal is dominant in the drive signal, and the contribution of the spatial frequency of the display pattern is relatively small. Therefore, unlike the first conventional method, voltage differences due to differences in display patterns are less likely to occur, but since the frequency components are generally higher, differences between the selection voltage and the non-selection voltage are less likely to occur (because both The difference appears in the high range of the drive frequency component)
The larger the number of scanning lines, the more disadvantageous it becomes, and the largest liquid crystal display panels currently in use produce display crosstalk that is unacceptable.

In order to avoid these problems, you can lower the resistance value of the signal line, but in reality, the signal line is made of a transparent conductive film.
It is not easy to significantly reduce this resistance value in terms of technology and cost.

In view of these points, the present invention prevents the drive frequency component from becoming extremely high, reduces the contribution of the spatial frequency component of the display pattern, maintains the difference between the selection voltage and the non-selection voltage, and maintains sufficient display contrast while maintaining shading. An object of the present invention is to provide a method for driving a liquid crystal display device and a device thereof that can provide a display with less unevenness.

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 13 to 15 show voltage waveforms according to an embodiment of the first invention of the present application. Figure 13(a), (bl.

(C1 indicates the scanning signal waveforms eY1, eY2, and eY3 applied to the scanning signal lines Yl, Y2, and Y3 in order to display the display screen in FIG. 4, respectively;
, (b), (C1 is the display signal line X(i-1
), Xi, and the display signal waveforms applied to X (i+1). The feature of the present invention is that the conventional method has one scanning period T.
Alternatively, the polarity of the signal is inverted at half of the l scanning selection time τ, whereas in the method of the present invention, the polarity is inverted every l stages, which is less than one scanning period T.
FIG. 15 corresponds to x=3.

In the figure, in the first three stages, the potential ■5 corresponds to the reference potential VO in FIG.
, V6 becomes the selection voltage vo-vx. In the next three stages, potential ■2 becomes reference potential ■0, and ■6 becomes scanning voltage VO.
+VY and V3 correspond to the non-selection voltage vo-vx, and Vl corresponds to the selection voltage vo-vx. Thereafter, polarity reversal is repeated every three stages. In this way, the drive voltage waveforms applied to the display pixels become as shown in FIG. , fb) eYl-e
Comparing X(i −1) and eYl−eXi), it can be seen that there is no large difference in frequency components. Furthermore, compared to the second conventional method in which the signal is inverted once during l scanning line selection period τ, it is also clear that the drive is performed with lower frequency components as a whole.

Next, the removal of the DC component, which is a basic condition in the method of driving a liquid crystal display device, will be explained.

Figure 16 shows a liquid crystal display device with eight scanning signal lines.
This diagram illustrates whether the polarity of the scanning signal voltage is positive or negative in each scanning period (frame) when the polarity of the drive signal is inverted every three stages. As shown in the figure, the same signal time is repeated every 24 stages, ie, 3 frames, in each scanning signal line, and the number of positive polarity scanning signals and the number of negative polarity scanning signals may not match. For example, in the first row, the ratio is 2 for positive polarity and 1 for negative polarity.

In general, the number of scanning signal lines is m2, the number of inversion stages is l, and m
Let the least common multiple of and , (m,
If jl)÷p is an even number, the polarity of the signal is reversed an even number of times in the signal time series, and the beginning of the signal time series always has the same polarity. Furthermore, if C, M, (m, I ÷ l is an even number, all prime factors of powers of 2 among L, C, M, (m, 1) will be included in m, L, C,
M, (m, n) 10m is always an odd number. However, if the period of the signal time series is expressed by the number of frames, it will always be an odd number. In this way, in a signal time series that repeats every odd frame, the number of frames with positive polarity and the number of frames with negative polarity do not match, and a DC component remains.

Here, it seems to be a special condition that L, C, M, (m, It) + jl are even numbers, but the number m of scanning signal lines is not consistent with the external circuit in a normal liquid crystal display device. In many cases, the number is set to a power of 2, and in this case, the above conditions are always met, and as mentioned above, the life of the liquid crystal decreases due to the residual DC, making it impossible to put it into practical use as it is. Become.

One way to solve this problem is to further invert the first polarity signal, which is inverted every l stages, according to a second polarity signal, which is inverted every stage L, C, M, (m, Il). This is a method in which a third polarity signal is generated using the third polarity signal, and the polarity of the actual drive signal is inverted in accordance with this third polarity signal.

Figure 17 shows m=8. This diagram shows the polarity of the scanning signal using this method in the case of β-3. In the figure, the polarity of the first polarity signal is in parentheses, the polarity of the second polarity signal is in parentheses, and the others are the actual scanning signals. The polarity of the signal, ie, the third polarity indicates the polarity of the signal. As mentioned above, the time series of the first polarity signal repeats the number of stages C, M, (m, A) for each scanning signal line, so this is inverted according to the second polarity signal. In this way, a drive signal of the necessary opposite polarity can be obtained for each time-series period, and therefore, the DC component of the drive signal can be removed.

Furthermore, if the above method is generalized, it is sufficient that the polarity of the second polarity signal is reversed an odd number of times during the time series period of the first polarity signal, C, M, (m) stages. This can be said to be the case.Since it is reversed an odd number of times, the opposite polarity is applied every time series period, and the DC component can be removed after all.Figure 18 is based on this idea, and when m = 8.J = 3, the second This diagram shows the polarity of the scanning signal when the polarity signal is inverted every frame. The symbol in parentheses is the first polarity signal, the symbol in parentheses is the second polarity signal, and the others indicate the polarity of the actual scanning signal. In the case of Figure 18, the first polarity signal forms a time series with a period of three frames, and the second polarity signal is inverted three times in one time series period, so the DC component is removed. Therefore, the merit condition is satisfied.

FIG. 19 is a configuration example of a driving device for a liquid crystal display device which is the second invention of the present application, and this device is the second invention of the present application.
This is for realizing an embodiment of the invention of the 11th invention.
In place of the frequency divider circuit 9 and waveform shaping circuit 10 in the circuit example in the figure, a (2XIl) frequency divider circuit (first polarity signal generation circuit) 13 and a (2×k) frequency divider circuit (second polarity signal generation circuit) ) 14 is provided, and a logic gate (third polarity signal generation circuit) is provided.
15, (2x the output of the frequency divider circuit 13 and (2xk)
An exclusive OR with the output of the frequency dividing circuit 14 is taken, and this is applied to the signal line 12 as a polarity signal. Here, the value of k is selected so that an odd multiple of k is equal to a natural number multiple of the least common multiple of m and l. Figure 20(a)-(d)
) are diagrams showing the main signals of the circuit in FIG. The waveform POLE is the output waveform of logic gate 15.

As is well known, exclusive OR is a logic that outputs "0" if the inputs match, and "1" if they do not match, and is inverted every time one scanning signal line is selected. The signal POLE-a is inverted for each scanning signal line.
It is further inverted by LE-b to become POLE. Using this as a polarity signal, Y drive circuit 2 and X drive circuit 3
It is clear that the driving method according to the first invention of the present application can be realized by the circuit of this embodiment.

In the above embodiment, the second polarity signal is inverted within the number of stages that is the least common multiple of C and m, but even if the second polarity signal is inverted within a period that is an integral multiple of the least common multiple,
Similar to the above embodiment, this has the effect of removing DC components.

Furthermore, the present invention is not limited to driving liquid crystal display devices, but can be used generally when it is necessary to average the frequency components of drive signals in time-division driving of circuit elements that require AC drive. The value is very great.

Furthermore, the polarity signal is sent to the shift register in the drive circuit.
Although it was generated from the TPOBB signal, it is not generally used in the form of a drive circuit, and since there is naturally a signal for recognizing one scanning line selection period on the control circuit side, it is used to generate a polarity signal. You may also do so.

As described above, according to the present invention, the first polarity signal, which is inverted every time fewer than four scanning signal lines are selected from m scanning signal lines, is Since the polarity of the drive signal is inverted according to the second polarity signal which is inverted an odd number of times during several times the number of stages, and the third polarity signal created thereby, the frequency of the drive signal is component is relatively low, and there is less dependence on the spatial frequency of the display pattern, display pixels in a matrix array of capacitive loads with finite wiring resistance can be driven with a uniform voltage, and density unevenness in the display pattern is reduced. Moreover, the direct current component of the drive signal is removed, and there is an effect that a decrease in the life of the liquid crystal can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the principle of the driving method of a liquid crystal display device, FIG. 3 is a non-selected waveform diagram, and FIG. 4 is a diagram showing an example of a display pattern of a liquid crystal display device formed in a matrix.
Fig. 5 is a scanning signal waveform diagram according to the first conventional practical driving method, Fig. 6 is a display signal waveform diagram thereof, and Fig. 7 is a selection voltage waveform and non-selection voltage waveform applied to the display pixel. 8 is a scanning signal waveform diagram according to the second conventional practical driving method, FIG. 9 is a display signal waveform diagram thereof, and FIG. 10 is a selection voltage waveform applied to the display pixel and a non-selection voltage waveform. Figure 11 is a circuit diagram for realizing a conventional practical driving method, Figure 12 is a time chart diagram of the circuit diagram in Figure 11, and Figure 13 is a diagram showing voltage waveforms. A scanning signal waveform diagram of a method for driving a liquid crystal display device according to an embodiment of the invention,
FIG. 14 is a diagram showing the display signal waveform, FIG. 15 is a diagram showing the selection voltage waveform and non-selection voltage waveform applied to the display pixel, and FIG. 16 is the scanning signal using only the first polarity signal in this driving method. FIG. 17 is a diagram showing an example of the polarity of the scanning signal by the third polarity signal created from the first polarity signal and the second polarity signal in the driving method,
FIG. 18 is a diagram showing the polarity of a scanning signal based on a third polarity signal generated from a second polarity signal different from that in FIG.
FIG. 9 is a circuit diagram of a driving device for a liquid crystal display device according to an embodiment of the second invention of the present application, and FIG. 20 is a time chart diagram of the circuit of FIG. 19. XI, X2. ..., Xi, ..., Xn... display signal line, Yl, Y2. ..., Yj, ..., Ym...
Scanning signal line, vo+vy...Scanning voltage, vo+vx・
...Non-selection voltage, vo-vx...Selection voltage, τ...
1 scanning line selection period (1 stage), ■...Display pixel,
2... Scanning signal line drive circuit, 3... Display signal line drive circuit, 4... Control circuit, 5... Display data line, 6...
...Scanning data line, 13...(2×β) frequency division circuit (first polarity signal generation circuit), 14...(2Xk) frequency division circuit (second polarity signal generation circuit), 15. ...Logic gate (third polarity signal generation circuit), POLE-a-...
1st polarity signal, POLE-b...2nd polarity signal, POLE...3rd polarity signal. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa 11th Y1 Figure 5 ρ ■ 1 Figure 6 Figure 7 Figure 8 Figure 9 (Q) Figure 10 Figure 13 Figure 14 Figure 15 (C) eYi-eX (i+1) Sade − ;→ Procedural amendment (1 shot) 587. :'S'6 Showa year, month, day Dear Commissioner of the Japan Patent Office 1. Case description Japanese Patent Application No. 58-129057 3. Part 5 to the representative of the person making the amendment, Hitoshi Katayama. 5. Detailed explanation of the invention in the specification subject to the amendment. Column 6, Contents of correction fll "Signal time" on page 17, line 10 of the specification is corrected to "signal time series."that's all

Claims (1)

[Claims] +11 For a liquid crystal display device in which a plurality (m) of scanning signal lines and a plurality (n) of display signal lines are arranged in an intersecting manner and a display pixel is formed at each intersection, the scanning signal lines are sequentially scanned. A selection voltage is applied to the display signal line where the selected pixel among the pixels on the scanning signal line to which the scanning voltage is applied is located, and a selection voltage is applied to the display signal line where the non-selected pixel among the pixels is located. In the method for driving a liquid crystal display device in which a desired liquid crystal display is performed by applying a non-selective voltage, the first method of (a) below is described.
Create a third polarity signal by inverting the polarity signal according to the second polarity signal in (b) below, and invert the polarity of the scanning voltage 2 selection voltage and non-selection voltage according to the third polarity signal. A method for driving a liquid crystal display device, characterized in that the scanning voltage 2 selection voltage and non-selection voltage having no DC component are applied to each signal line. (a) r scanning signal lines for m scanning signal lines (here, ρ is the m
The least common multiple of and a natural number p smaller than m! A polarity signal whose polarity is inverted each time a scanning signal line (a natural number such that the value divided by is an even number) is selected. (b) A polarity signal whose polarity is inverted an odd number of times at equal time intervals during a period in which a number of scanning signal lines that are a natural number multiple of the least common multiple of m and 4 are selected. (2) In a driving device for a liquid crystal display device that drives a liquid crystal display device in which a plurality (m1 scanning signal line and a plurality (0) display signal lines) are arranged in an intersecting manner and a display pixel is formed at each intersection, the liquid crystal display device shown in FIG. A control circuit that generates scanning data and display data to cause the display device to display a desired display, and p of the m scanning signal lines (where l is the minimum of the m and a natural number ρ smaller than m). a first polarity signal generation circuit that generates a first polarity signal that is inverted for each scanning signal line (a natural number such that the value obtained by dividing the common multiple by l is an even number); and a least common multiple of the above l and m. a second polarity signal generation circuit that generates a second polarity signal whose polarity is inverted an odd number of times at equal time intervals during a period in which a natural number multiple of scanning signal lines are selected;
a third polarity signal generation circuit that inverts the first polarity signal according to the second polarity signal to generate a third polarity signal; a scanning signal line drive circuit that applies a scanning voltage to the scanning signal line with a polarity of , and a selection voltage and a non-selection voltage that apply the display data to the display signal line with a positive or negative polarity depending on the third polarity signal; 1. A driving device for a liquid crystal display device, comprising: a display signal line driving circuit which applies the scanning voltage 1 selection voltage and non-selection voltage having no DC component to each signal line.