JPH1124042A - Liquid crystal display device and its driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to keep a moving picture characteristic while providing a sufficient relaxation time by splitting picture elements of liquid crystal elements into a plurality of scanning blocks and sequentially jump- scanning the scanning lines over each block. SOLUTION: By using an inactive period for 1-th, m-th, and n-th scanning lines of block A, the scanning lines of the other block B through block E are scanned. For example, there is an inactive period for 4H from 1-th pulse A of block A up to m-th pulse A of block A. In this period, pulse A is given the four scanning lines of 1-th one of block B, 1-th one of block C, 1-th one of block D, and 1-th one of block D. Assuming a write pulse width (a pulse width of pulse B) as 20 μsec a single scanning time is 50 μm, and for example, in the case of a display element of S-VGA (600 scanning lines ×800 information lines), a frame frequency is about 33 Hz, and this provides a frame frequency of performance endurable to a moving picture display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ferroelectric liquid crystal (F).
LC) and a driving method thereof using a liquid crystal display (LC).
In particular, the present invention relates to a liquid crystal display device that performs gradation display by a matrix driving method and a driving method thereof.

[0002]

2. Description of the Related Art A display device using a ferroelectric liquid crystal is disclosed in Japanese Patent Application Laid-Open No. 61-94023. 1 to 3 μm so that the transparent electrode is on the inner surface.
It is well known that a ferroelectric liquid crystal is injected into a liquid crystal cell having a cell gap of about μm.

A ferroelectric liquid crystal element has two stable states, a light transmitting state and a blocking state, and is mainly used as a binary (white / black) display element. However, a multi-valued display, that is, a halftone display is also possible. . Japanese Patent Application Laid-Open No. 4-218 as a halftone display method
As disclosed in Japanese Unexamined Patent Publication No. 022 and No. 5-158444, an area gray scale method has been proposed in which an intermediate light transmission state is formed by controlling an area ratio of a bistable state in a pixel. I have. Hereinafter, this method will be described.

FIG. 8 is a diagram schematically showing the relationship between the switching pulse amplitude and the light transmittance in a ferroelectric liquid crystal element. A cell (element) which is initially in a completely light-blocked (black) state is shown.
7 is a graph in which the amount of transmitted light I after applying a one-shot pulse of one polarity is plotted as a coefficient of the amplitude V of the one-shot pulse. When the pulse amplitude V is equal to or less than the threshold value Vth (V ≦ Vth), all the pixels remain in the light blocking state, so that the amount of transmitted light does not change, and the transmitting state after pulse application is as shown in FIG. 9B. This is the same as the state of FIG. 9A showing the state before application. The pulse amplitude V exceeds the threshold value Vth (Vth <V <Vsa
t) and a part of the pixel is in the other stable state, that is, FIG.
The state transits to the light transmission state shown in (c) and shows an intermediate amount of transmitted light as a whole. When the pulse amplitude further increases and the pulse amplitude V becomes equal to or higher than the saturation value Vsat (Vsat ≦ V), as shown in FIG. 9D, all the pixels are in the light transmitting state, and the light amount reaches a constant value. That is, in the area gradation method, halftone display is realized by controlling the voltage so that the pulse amplitude V becomes (Vth <V <Vsat).

However, the relationship between the amplitude V of a single pulse and the amount of transmitted light I shown in FIG. 8 depends on the cell gap, temperature, and the like. That is, if there is a cell gap distribution or a temperature distribution in the cell, different grayscale levels are displayed for applied pulses having the same pulse amplitude. FIG. 10 is a graph for explaining this, and is a graph showing the relationship between the pulse amplitude V and the amount of transmitted light I as in FIG. 8, but showing the relationship between the two at different temperatures, that is, the relationship at high temperatures. And a curve L indicating a relationship at a low temperature. Generally, in a display having a large display size, it is not uncommon for a temperature distribution to occur in the same cell. Therefore, even if an attempt is made to display a halftone by a certain driving voltage Vop, as shown in FIG. In some cases, the halftone level in the same cell varies, making it impossible to obtain a uniform gradation display.

A driving method (hereinafter referred to as a four-pulse method) that solves the above-mentioned problem has been proposed in Japanese Patent Application Laid-Open No. Hei 4-218022. In the four-pulse method, the same amount of transmitted light is obtained by applying a plurality of pulses to all of a plurality of pixels which are on the same scanning line as one cell and have different thresholds due to the influence of temperature distribution and the like. Is to get.

Specifically, the following series of write operations are performed. FIG. 11 is a diagram showing a driving waveform of the 4-pulse method, FIG. 12 is a diagram for explaining a driving means of the 4-pulse method, FIG.
FIG. 3 illustrates a display state when the four-pulse method is used. The pulses (A) to (D) shown below are all scanning waveforms. First, the entire surface of the cell is written to a certain state Q0 by the reset pulse (A) (entire reset). The reset pulse (A) is a waveform having a sufficient energy for a composite voltage of the scanning waveform and the information waveform to reset the entire surface, no matter what information waveform comes. Second, a pulse (B) having a polarity opposite to that of the pulse (A) is applied. A voltage obtained by combining the pulse (B) and the information waveform is applied to the pixel, the pixel in the high threshold portion of the cell is written until the light transmittance of Ia% is reached, and the pixel in the low threshold portion of the cell is completely written. Inverted Q10
It becomes a state of 0. Assuming that the light transmittance in the state of Q0 is 0%, Q1 is 100% and that of Qa is Ia%. Third, a pulse (C) having a polarity opposite to that of the pulse (B) is applied.
The information waveform at this time is 0V. Then, no switching occurs in the pixels in the high threshold portion of the cell, and the state Qa created by the pulse (B) is stored. On the other hand, the state of Q100 (light transmittance of 100%) is changed from the state of Q100 (light transmittance of 100%) to the state Qb of light transmittance (100-Ib)% in the pixel at the low threshold value portion of the cell. Fourth, a pulse (D) having a polarity opposite to that of the pulse (C) is applied. A voltage obtained by combining the pulse (D) and the information waveform is applied to the pixel, and the pixel in the high threshold portion of the cell stores the state Qa created by the pulse (B), and the pixel in the low threshold portion of the cell The state changes to the state Qc with a light transmittance of (100−Ib + Ic)%. The information waveform at this time is a pulse (B)
Has the same shape as the information waveform synthesized. Thus, finally, the pixels in the high threshold portion and the pixels in the low threshold portion of the cell realize the same light transmittance state Qa. FIG. 12 shows that the transmittance Ta% and the transmittance (100−Ib + Ic)% are the same.
It is clear from the fact that the triangle abc and the triangle a'b'c 'in the middle are congruent.

Further, Japanese Patent Application Laid-Open No. Hei 5-158444 proposes a pixel shift method in which the writing time is shorter than the four-pulse method. In the pixel shift method, by inputting and selecting different scanning signals to a plurality of scanning signal lines at the same time, a distribution of the electric field intensity over the plurality of scanning lines is created, and gradation display is performed. The outline of the pixel shift method will be described below.

The liquid crystal cell used has a threshold distribution within one pixel as shown in FIG. In the figure, 81 is glass, 82 is liquid crystal, 83 is an information side electrode, 84 is a scanning side electrode, 85 is a base layer, and 86 is an alignment film. FIG. 15A is a diagram schematically illustrating the relationship between the switching pulse amplitude and the light transmittance when pixels on two scanning lines are grouped together. Here, characteristics at three temperatures T1, T2, and T3 existing in the panel surface are shown by three lines, respectively. Note that the cause of the threshold value variation is other than the temperature change, but here, for convenience of explanation, the description will be made mainly using the temperature change.

In FIG. 15A, the transmittance is 0% to 100%.
Is the display area of the pixel B on the scanning line 2, and the transmittance is 100%.
〜200% is represented as a display area of the pixel A on the scanning line 1. Since one pixel is constituted per one scanning line, when two pixels are simultaneously scanned, the transmittance when both the pixel A and the pixel B are all in the light transmitting state is set to 200 for convenience.
%. In the pixel shift method, two scanning lines are simultaneously selected for one piece of gradation information, but one gradation information is displayed in a region having an area of one pixel.

In FIG. 15, at the temperature T1, the input gradation information is 0% when the applied voltage is V0, and 10% when the applied voltage is V100.
It is written in the range corresponding to 0%. As can be seen from the figure, at the temperature T1, this gradation control range (pixel region) is entirely on the scanning line 2. However, when the temperature changes from T1 to T2
When the same voltage is applied to the pixel, the region higher than the temperature T1 in the pixel is inverted. To correct this, the temperature T2
Is set so as to extend over the scanning line 1 and the scanning line 2. When the temperature further rises to T3,
The image area to be drawn by changing the applied voltage from V0 to V100 is set only on the scanning line 1.

In this manner, by displaying the pixel area for performing the gradation display by the temperature on the two scanning lines while shifting, the gradation display can be correctly performed in the temperature range from T1 to T3. Pixel A having the same voltage-transmittance characteristic
In order to cause the pixel A to display 100 to 200% using the pixels A and B, for example, the amplitude of the selection pulse of the pixel A (corresponding to the pulse (D) of the four-pulse method) is set to (Corresponding to B)) is set to be smaller by Vsat-Vth than the amplitude of (B). In the pixel shift method, 4
Since the pulses corresponding to the pulses (D) and (B) of the pulse method can be applied to the pixels A and B at the same timing, the writing time can be reduced compared to the four-pulse method.

[0013]

However, when the above-described gradation driving method such as the four-pulse method or the pixel shift method is used, the following drawbacks may occur. That is, in order to realize the above-mentioned gradation driving method, it is necessary to perform writing by the next pulse after the optical response of the liquid crystal by each writing is sufficiently settled. Here, the time until the optical response of the liquid crystal sufficiently falls is called a relaxation time. The relaxation time will be described below.

FIGS. 16 and 17 are graphs showing the state of the relaxation time. FIG. 16 shows a change in the amount of transmitted light when a single pulse is applied. As shown in FIG. 16, it takes about 200 μsec to settle down to a certain light amount level after applying the write pulse. FIG. 17 shows a change in the final transmitted light amount when another pulse (crosstalk pulse) is applied after the application of the write pulse. The crosstalk pulse is a bipolar pulse of ± Vc, the pulse width of each polarity is the same as the write pulse width, and the pulse amplitude | ± Vc | is a value sufficiently smaller than the inversion threshold Vth. The final transmitted light amount depends on the idle period T between the write pulse and the crosstalk pulse, and the idle period T
Is greater than or equal to 200 μsec, the final transmitted light quantity is substantially unaffected by the subsequent crosstalk pulse. This also indicates that the relaxation time is about 200 μsec.

Therefore, it takes about 200 μm between each write pulse.
Considering the matrix drive under the condition that the time is longer than sec, the waveform shown in FIG. 18 can be considered. In the case of the drive waveform shown in this figure, the write pulse width (pulse width of pulse (B))
Is set to 20 .mu.sec, it takes 250 .mu.sec to scan one scanning line. For example, S-
When a VGA (600 scanning lines × 800 information lines) display element is considered, the frame frequency is about 7 Hz, and moving image information and the like are extremely poor display quality.

The present invention has been made in view of the above-mentioned problems in the conventional example, and has as its object to provide a liquid crystal display device having sufficient moving image characteristics while providing a sufficient relaxation time.

[0017]

According to the present invention, there is provided a scanning electrode group provided on each electrode substrate with a ferroelectric liquid crystal sandwiched between two electrode substrates disposed opposite to each other. A pixel is formed at the intersection of the liquid crystal display element and the information electrode group, and when performing a gradation display on a ferroelectric liquid crystal display element having a threshold distribution formed in each pixel, at least two or more pixels of the liquid crystal display element are used. , And scanning lines are sequentially skipped over each block.

In a preferred embodiment of the present invention,
The number of scanning blocks is changed according to the writing characteristics of the ferroelectric liquid crystal. Each of the above scanning blocks is sequentially (non-interlaced) scanned. Further, gradation display is performed over pixels on two adjacent scanning electrodes of the liquid crystal display element. In this case, the final scan line in the scan block divided into at least two or more blocks is
By combining one of the plurality of pulses of the last scan line itself in the scan block with the gray scale information of the first scan line in the scan block physically adjacent to the scan block, the difference with respect to the temperature change is obtained. Compensates for key display. When the last scanning line in the scanning block is the last scanning line of the liquid crystal display element, the scanning line changes its temperature by synthesizing its own gradation information and one of its own plurality of pulses. Is compensated for gradation display.

[0019]

According to the above arrangement, the screen of the liquid crystal display for performing the gradation display by the matrix driving method is divided into a plurality of scanning blocks, and the interlaced scanning is performed over each scanning block. Even when the pixel shift method is adopted, the frame frequency can be increased by the number of divisions, and the display quality can be improved.

FIG. 1 shows an example of a driving waveform suitable for the pixel shift method. In the pixel shift method,
The time relationship between adjacent scanning lines required for compensation is the same as in FIG. 18, and the frame frequency can be increased by scanning another scanning line during the idle period in FIG.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of a display device according to an embodiment of the present invention, and FIG. 3 is a communication timing chart of image information. The graphic controller 125 transfers scanning line address information and image information for designating scanning electrodes of the display element 121 to the panel controller 124. In this embodiment, since the scanning line address information and the image information are transferred on the same transmission line, the two types of information must be distinguished. The signal for this identification is AH / DL in FIG. 3, and when the AH / DL signal is at “H” level, PD0 to PD0
Indicating that the PD 15 is the scanning line address information,
The “L” level indicates that PD0 to PD15 are image information. The scanning line address information is converted into image information PD0 to PD15 by a panel controller 124 in the liquid crystal display device.
After being extracted from the image information transferred as the image data and decomposed into four scanning line address information of pulse (A) to pulse (D), the scanning line driving circuit is synchronized with the timing for driving the designated scanning line 123. The scanning line address information is transferred to the decoders 1 to 4 in the scanning line driving circuit 123, and the designated scanning of the display panel 121 is performed via the decoders 1 to 4 according to the scanning waveform control information from the scanning waveform control circuit. Applied to the electrodes. on the other hand,
The image information is transferred to a shift register in the information line drive circuit 122, and is shifted in units of 16 bits by a transfer clock. When the shift register completes the shift of one scanning line in the horizontal direction, it is transferred to the line memory in the information line driving circuit 122 and stored for one horizontal scanning period, and the image information and the information waveform control circuit 122 are stored. Is applied to the information line electrode according to the information waveform control information.

In this embodiment, the driving of the display panel 121 and the graphic controller 1 in the liquid crystal display device are performed.
Since the generation of the scanning line address information and the image information in 25 is performed asynchronously, it is necessary to synchronize the devices when transferring the image information. The signal that governs this synchronization is shown in FIG.
The HSYNC is generated by the panel controller 124 in the liquid crystal display every one horizontal scanning period. The graphic controller 125 always monitors the HSYNC signal. When the HSYNC signal is at "L" level, image information is transferred. When the HSYNC signal is at "H" level, image information for one horizontal scanning line is transferred. After completion, no transfer is performed.
That is, when the graphic controller 125 detects that the HSYNC signal in FIG. 3 has become “L” level, it immediately sets the AH / DL signal to “H” level and starts transferring image information for one horizontal scanning line. . The panel controller 124 in the liquid crystal display device sets the HSYNC signal to the “H” level during the image information transfer period. After the writing to the display element 121 is completed after a predetermined horizontal scanning period,
The panel controller 124 can receive the image information of the next scanning line by returning the HSYNC signal to the “L” level again. The graphic controller 125 has a frame memory, and the graphic controller can transfer image information for an arbitrary scanning line.

FIG. 1 is a timing chart of driving waveforms in the first embodiment of the present invention.
The relationship between the pulses (A) to (D) of the scanning lines of block #l, m and n is the same as in FIG.

The pulse (A) is a waveform in which the combined voltage of the scanning waveform and the information waveform has sufficient energy to reset the entire surface regardless of the type of the information waveform, while the pulse (C) is applied. , The information waveform is 0V. Therefore, the pulse (A) and the pulse (C) can provide the liquid crystal with writing characteristics which are not affected by the information waveform.

Therefore, a scanning line of another scanning block can be scanned between the pulse (B) and the pulse (D) of the A block. The rest period between pulse (B) and pulse (D) depends on the relaxation time mentioned above, here 4H minutes
(About 200 μsec). In the case of the pause period of 4H, a scanning waveform of another four blocks can be applied between the pulse (B) and the pulse (D) of the A block. FIG. 4 is a schematic diagram divided into five scanning blocks A to E. In this case, the scanning order is A block-1,
B block No. 1, C-1, D-1, E-1, A-2,
Scanning is performed in the order of B-2. The number of scanning blocks is 2 if the idle period is 1H, and 3 if the idle period is 2H, and may be determined according to the characteristics of the liquid crystal.

The above driving method will be described in detail with reference to FIG. The other scanning line from block B to block E is to be scanned using the idle periods of the scanning lines of block A-1 (m), m and n. For example, there is a pause of 4H from the pulse (A) of block A-1 to the pulse (A) of block A-m. Here B
Block-l (L) number, C block l (L) number,
A pulse (A) is applied to four (1) -th scanning lines of the D-block and l- (l) of the E-block. Similarly, for the pulse (B), the pulse (C), and the pulse (D), the idle period is completely filled by using the idle period of the scanning line of the A block. At this time, there are pulses of different scanning lines within the same 1H period. However, since the pulses (A) and (C) provide the liquid crystal with a drive characteristic independent of the information waveform, the other scanning lines are used. There is no problem at all even if the waveform is superimposed on the waveform. Therefore, if the time relation between the pulse (B) and the pulse (D), that is, the fact that the pulse (B) and the pulse (D) of the adjacent scanning line in the same scanning block exist in the same 1H period, It has no effect on the driving characteristics of the liquid crystal. By the driving method described above, the write pulse width (pulse width of pulse (B)) is set to 20 μsec.
Then, the time per scanning line is 50 μsec, and for example, S-VGA (600 scanning lines × 800 information lines)
When the display element is considered, the frame frequency is about 33 Hz, and a frame frequency with a performance that can endure displaying moving images can be obtained.

The following points must be considered at the breaks of the scanning block. That is, the information waveform synthesized with the pulse (D) of the last scanning line of each block uses the information waveform of the first scanning line of the adjacent scanning block. FIG. 4 is a diagram showing a scanning block in the first embodiment, and FIG. 5 is a diagram showing A to E in the first embodiment.
FIG. 6 is a diagram for explaining a method of scanning a break between scan blocks up to the present. In the scanning address information in FIG. 5, four types of addresses are given in each one horizontal scanning period (1H).
This specifies the pulses (A) to (D),
For example, the first address in FIG.
The pulse (A) is designated to the 0th scan line, the pulse (B) is designated to the A block-120 scan line, and the pulse (D) is designated to the C block-119 scan line. Figures 4 and 5 show S-
FIG. 6 is a diagram for explaining a case of VGA resolution (600 scanning lines × 800 information lines). The waveform synthesized with the pulse (D) of the A block-120 scan line must be the information waveform of the B block-1 scan line. Then, during the same 1H period, the pulse (D) is output to the A-line # 120 scanning line and the pulse (B) is output to the B-block # 1 scanning line. However, in such a case, the B block-1 scan line is scanned next to the B block-120 scan line.
The scanning of the A block-1 scan line cannot be performed, the scanning order is changed, and a phenomenon such as flickering is likely to occur. Therefore, block A-120, B
Block-120, Block C-120, Block D-120, Block E-120 At the timing of the pulse (D) of the scanning line, only the information waveform synthesized with the pulse (D) is applied to the information line. The application of the scanning waveforms of the B block # 1, the C block # 1, the D block # 1, the E block # 1, and the A block # 1 is not performed. As a result, the scanning order starting from the A-block-1 scan line can be maintained. Since the E-block-120 scanning line has no adjacent scanning block, the information waveform of itself (E-block-120) is used as the information waveform combined with the pulse (D).

[0028]

FIG. 6 shows a second embodiment of the present invention.
FIG. 6 is a diagram for explaining a method of scanning a break between scanning blocks from E to E. FIG. 6 is a diagram for explaining the case of XGA resolution (768 scanning lines × 1024 information lines). In this case, when the scanning lines are divided into five blocks, the number of scanning lines in each block differs depending on the block. The number of scanning lines in each block is, for example, in the case of 768 scanning lines, A to D blocks are 15
There are four lines, 152 blocks only for E blocks, or 154 scan lines for A and B blocks and 153 scan lines for C to E blocks. Here, 154 blocks for A to D blocks and E block Only the case of 152 lines will be described.

In this case, as in the first embodiment, the information waveform of the first scanning line of the adjacent block is synthesized with the pulse (D) of the last scanning line of each block. Since the number of scanning lines is small, a 1H pause period is inserted between the information waveform of the D-block-154th scanning line and the information waveform of the B-block-1st scanning line.

FIG. 7 is a diagram for explaining a method of scanning a break between scanning blocks A to E in the third embodiment. FIG. 7 is a diagram for explaining the case of the XGA resolution (768 scanning lines × 1024 information lines) as in FIG. The difference from the second embodiment is that the information waveform of the D block-154th scanning line and the information waveform of the B block- 1st scanning line have A
That is, the information waveform of the block-1 scan line is inserted to eliminate the pause period. Also, at this time, unlike the first and second embodiments, the A block-1 scan line can be applied sequentially from the pulse (A) without interfering with the pulses of the other scan lines. In addition, it is possible to realize a scanning method that does not require a pause period.

[0031]

As described above, according to the present invention, a high frame frequency can be realized and the display quality can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a driving waveform according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a display device according to an embodiment of the present invention.

FIG. 3 is a communication timing chart of image information of the display device of FIG. 2;

FIG. 4 is a schematic diagram showing a scanning block according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a driving waveform according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a driving waveform according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a drive waveform according to a third embodiment of the present invention.

FIG. 8 is a diagram showing driving characteristics of a ferroelectric liquid crystal cell.

FIG. 9 is a diagram showing a display state based on the drive characteristics of FIG.

FIG. 10 is a diagram showing a change in driving characteristics depending on the temperature of the ferroelectric liquid crystal cell.

FIG. 11 is a diagram showing a driving waveform of the four-pulse method.

FIG. 12 is a diagram showing a driving means of a four-pulse method.

FIG. 13 is a diagram showing a display state when the four-pulse method is used.

FIG. 14 is a schematic view of a ferroelectric liquid crystal cell.

FIG. 15 is a diagram showing a driving means of the pixel shift method.

FIG. 16 is a diagram showing a state of a relaxation time when a single pulse is applied.

FIG. 17 is a diagram showing the influence of crosstalk pulses on transmittance.

FIG. 18 is a diagram showing a driving waveform of the pixel shift method.

[Explanation of symbols]

81: glass, 82: liquid crystal, 83: information side electrode, 84:
Scanning electrode, 85: base layer, 86: alignment film, 121: display element, 122: information line drive circuit, 123: scanning line drive circuit, 124: panel controller, 125: graphic controller.

Claims (7)

[Claims] A pixel is formed at an intersection of a scanning electrode group and an information electrode group provided on each electrode substrate with a ferroelectric liquid crystal sandwiched between two electrode substrates arranged opposite to each other. A ferroelectric liquid crystal display element formed with a threshold distribution in a pixel,
A liquid crystal display device comprising: a driving unit for performing gradation display on the liquid crystal display element; wherein the driving unit divides the pixels of the liquid crystal display element into at least two or more scanning blocks, and scans the scanning lines over each block. A liquid crystal display device, which sequentially scans the data. 2. A pixel is formed at the intersection of a scanning electrode group and an information electrode group provided on each electrode substrate by sandwiching a ferroelectric liquid crystal between two electrode substrates arranged opposite to each other. In a driving method for performing gradation display on a ferroelectric liquid crystal display element having a threshold distribution formed in a pixel, a pixel of the liquid crystal display element is divided into at least two or more scanning blocks, and scanning is performed over each block. A method for driving a liquid crystal display element, wherein lines are sequentially skipped and scanned. 3. The driving method according to claim 2, wherein the number of scanning blocks is changed according to a writing characteristic of the ferroelectric liquid crystal. 4. The driving method according to claim 2, wherein the scanning block is sequentially scanned. 5. The driving method according to claim 2, wherein gradation display is performed over pixels on two adjacent scanning electrodes of the liquid crystal display element. 6. A final scanning line in a scanning block divided into at least two or more blocks, wherein one of a plurality of selection pulses of the final scanning line itself in the scanning block and a physical pulse in the scanning block. 6. A driving method according to claim 5, wherein the gradation display is compensated for a temperature change by synthesizing the gradation information with the gradation information of the first scanning line in the adjacent scanning block. 7. When the last scan line in the scan block is the last scan line of the liquid crystal display element, the scan line combines its own gradation information with one of its own plurality of pulses. 7. The driving method according to claim 6, wherein the gradation display is compensated for the temperature change by the following method.