JP2000147466A - Method for driving liquid crystal display element and information display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an information display device which is high in safety, is small, thin and light and is convenient to carry and a method for driving liquid crystal display element capable of fast forward mode. SOLUTION: This information display device displays information by impressing pulse voltage to the scanning electrodes and signal electrodes arranged in a matrix form on a liquid crystal display element formed by holding the liquid crystals exhibiting a cholesteric phase between transparent substrates, thereby selecting the liquid crystals existing in intersected positions to a planar state or focal conic state. The signal pulse voltage for driving the display element is set plural times with respect to one pixel, by which images are rapidly displayed while the contrast is low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a reflective liquid crystal display device having a memory function and an information display device using the display device.

[0002]

BACKGROUND OF THE INVENTION At present, information is provided over a wide area by printed matter, but there is concern that it will be discarded as garbage and that forest resources for pulp and paper will be depleted. The present inventors distribute information recorded on a conventional paper in a state recorded on a digital information recording medium, and establish a mode in which a user can read the information on a display device such as a liquid crystal display. With the idea that the resource problem will be alleviated,
We are developing an electronic book system using liquid crystal display elements. As information, we believe that any printed matter such as books (paperback books, weekly magazines, monthly magazines, specialized magazines, etc.), newspapers, and advertising magazines can be replaced with such a system.

[0003] Digital information of books is distributed as a recording medium by a publisher (manufacturer), and a general user who owns (or rents) a reproduction display device can copy the recording medium to an electronic book device main body (liquid crystal display). Display system) to view (reproduce) information.

[0004] In order to achieve the above systematization, it is necessary to finish the device as small and thin as a book, and to be freely open and viewable anywhere. For that purpose, it is necessary to use a memory-type liquid crystal display element with low power consumption and to make the power supply compact. In addition, in order to reduce the weight and thickness of the apparatus, it is necessary to adopt a reflection type that does not require a light source. That is, it is necessary to mount a reflective liquid crystal display element having a memory property.

However, it has been found that the reflection type liquid crystal display element having the memory property has a peculiar drawback that the drive response speed is slow, and the above system depends on how to overcome this drawback. . If the response speed is improved, the display screen can be flipped like a book (fast-forward mode), and the above-described electronic book can achieve the same handling function as a book.

[0006]

Heretofore, a display device using a liquid crystal display element has used a low-molecular liquid crystal. For this reason, the type using a glass substrate has a problem that, when the substrate is large, it is difficult to uniformly apply a rubbing orientation treatment and the substrate is easily broken. Further, the viewing angle of the display unit was narrow, and it was difficult to read the displayed information. Furthermore, when a shock or pressure is applied to the display panel itself, the orientation is disturbed, and the image information cannot be read.For example, the liquid crystal itself does not have a memory property, and it is necessary to always supply constant power during display.
There is also a problem that power consumption is large.

[0007] In view of the above problems, an object of the present invention is to provide a small, thin, lightweight, and convenient portable device, which does not necessarily require the use of a glass substrate, has high safety, and has an even display. An object of the present invention is to provide an information display device that requires less power consumption. It is a further object of the present invention to provide a method of driving a liquid crystal display device capable of performing a display mode (fast forward mode) similar to flipping pages of a printed matter by speeding up the driving response of the liquid crystal. The present invention proposes an information display device that is put to practical use as a portable electronic book and that also considers the electronic information supply mode (bending system).

[0008]

In order to achieve the above objects, the driving method according to the present invention uses a reflective liquid crystal display element having a memory function, and uses a signal pulse voltage for driving the display element. At least one pixel is set a plurality of times.

In the present invention, a reflective liquid crystal display device having a memory function is used. Liquid crystals that exhibit a cholesteric phase at room temperature (eg, chiral nematic liquid crystals)
It is preferred to use This type of liquid crystal having memory properties does not require the use of glass for the substrate, and thus has no risk of breakage. In addition, orientation control is easy, the viewing angle is wide, and no unevenness occurs even on a large screen. In addition, since it has a memory property, it is economical because power is not consumed for maintaining the display, there is no adverse effect of noise, and the display can be maintained even when the power is cut off.

In the driving method according to the present invention, the second driving mode in which the signal pulse voltage is set a plurality of times for one pixel is referred to as a fast-forward mode. In this fast-forward mode, one signal pulse voltage has a narrow pulse width, a low-contrast image is displayed in a short time, and the contrast increases with an increase in the number of times of application of the signal pulse voltage. The image is displayed. For a quick glance at the image and a rough idea of the information, the fast forward mode can be executed in page order. An effect similar to a fade-in in which the contrast increases as the number of times of application of the signal pulse voltage increases from an image having a low contrast can be exerted, and this can be used to reproduce a halftone. Further, information (for example, characters) can be increased with an increase in the number of times of application of the signal pulse voltage, and a complete screen can be finally displayed.

In particular, if a liquid crystal exhibiting a cholesteric phase at room temperature is sandwiched between transparent plastic films, a thin and lightweight information display device which is strong against external forces (bending and impact) can be obtained. It is ideal for portable information devices such as e-books, etc., which are targeted by the company.

Further, in the driving method according to the present invention, if the next information is displayed so as not to overlap the currently displayed information, the time for turning off the overlapped pixel once and turning it on again can be omitted, and the screen can be displayed on the screen. Switching time is shortened as a whole. If a film-like speaker is incorporated, it can be used as an information display device with sound, and in particular, information shortage in the fast-forward mode can be supplemented by sound.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a method for driving a liquid crystal display device and an information display device according to the present invention will be described with reference to the accompanying drawings.

(Display Element Using Liquid Crystal Showing Cholesteric Phase) In a liquid crystal display element in which a cholesteric liquid crystal or a chiral nematic liquid crystal is sandwiched between two substrates, display is performed by switching the state of the liquid crystal between a planar state and a focal conic state. Do. When the liquid crystal is in the planar state, the helical pitch of the cholesteric liquid crystal is P, and the average refractive index of the liquid crystal is n.
Then, light having a wavelength λ = P · n is selectively reflected.
In the focal conic state, when the selective reflection wavelength of the cholesteric liquid crystal is in the infrared light range, it is scattered, and when it is shorter than that, it transmits visible light. Therefore, by setting the selective reflection wavelength in the visible light range and providing the light absorbing layer on the side opposite to the observation side of the element, it is possible to display the selective reflection color in the planar state and display black in the focal conic state. In addition, by setting the selective reflection wavelength in the infrared light range and providing a light absorption layer on the side opposite to the observation side of the element, light in the infrared light range is reflected in the planar state, but the wavelength in the visible light range is reflected. Is transmitted, so that a black display and a white display due to scattering in the focal conic state are possible.

By the way, if the first threshold voltage for untwisting the liquid crystal exhibiting the cholesteric phase is Vth1,
After the voltage Vth1 has been applied for a sufficient time, the voltage becomes lower than a second threshold voltage Vth2 which is lower than the first threshold voltage Vth1, and a planar state is established. Further, when a voltage of Vth2 or more and Vth1 or less is applied for a sufficient time, a focal conic state is established. These two states are stable even after the voltage application is stopped. It is also known that a mixture of these two states exists, and it is known that gray scale display is possible (see US Pat. No. 5,384,067).

Since the liquid crystal exhibiting the cholesteric phase has a memory characteristic capable of maintaining a display state even when no voltage is applied, a display element divided into a plurality of pixels is driven by a simple matrix drive to obtain a desired image or character. Can be displayed. However, since this type of liquid crystal has a hysteresis characteristic, the display state is different even with the same driving voltage due to the state before the liquid crystal.

In view of the above, according to the present invention, the liquid crystal constituting all the pixels is simultaneously reset to a focal conic state which requires a long time for selection, and then the liquid crystal constituting each pixel is reset. Are sequentially applied to select the display state of the liquid crystal constituting all the pixels. According to this driving method, all the pixels are simultaneously reset to the focal conic state, so that the long selection time required to select the focal conic state is required only once for one screen. As a result, the rewriting speed is improved when simple matrix driving is performed.

In the liquid crystal display element used in the present invention, the liquid crystal material is sandwiched in the order of resin film / transparent electrode / alignment control film / liquid crystal material / alignment control film / transparent electrode / resin film as described in detail below. The alignment is determined by the combination of the alignment control film and the liquid crystal material. Usually, the alignment process is the same for the upper and lower layers, but this combination may be changed depending on the colorization, driving method, application, and the like.

Although such names are used for the orientation control film for convenience, the function is not always clear. Rather than the general effect of controlling the alignment of liquid crystal molecules,
It can be said that the effect of improving the stability is great.

(Configuration of Liquid Crystal Display Element) FIG. 1 shows an example of a reflection type liquid crystal display element used in the present invention. In the liquid crystal display element 10, a red display layer 11R for performing display by switching between red selective reflection and a transparent state is disposed on a light absorber 19, and display is performed thereon by switching between green selective reflection and a transparent state. A green display layer 11G to be performed is stacked, and a blue display layer 11B for performing display by switching between blue selective reflection and a transparent state is further stacked thereon.

Each of the display layers 11R, 11G, and 11B has a resin-made columnar structure 15 and a liquid crystal 16 sandwiched between transparent substrates 12 on which transparent electrodes 13 and 14 are formed, respectively. Further, an orientation control film or an insulating film (not shown) may be provided on the transparent electrodes 13 and 14.

The transparent electrodes 13 and 14 are respectively connected to the driving circuit 2
0, and the transparent electrode 1
A predetermined pulse voltage is applied between 3 and 14, respectively. In response to the applied voltage, the display is switched between a transparent state in which the liquid crystal 16 transmits visible light and a selective reflection state in which visible light is selectively reflected.

The transparent electrodes 13 and 14 provided on the respective color display layers 11R, 11G and 11B are each composed of a plurality of strip electrodes arranged in parallel with a fine interval therebetween, and the directions of the strip electrodes are mutually aligned. They are opposed so as to be at right angles. Current is sequentially applied to these upper and lower strip electrodes. That is, display is performed by sequentially applying a voltage to each liquid crystal 16 in a matrix. This is called matrix driving. The liquid crystal display element 1 is formed by sequentially or simultaneously performing such matrix driving for each color display layer.
A full color image is displayed at 0.

By providing the light absorber 19 in the lowermost layer with respect to the viewing direction (the direction of arrow A), each color display layer 1
Light transmitted through 1R, 11G, and 11B is all light absorber 19
Is absorbed by That is, if all the color display layers are in a transparent state, black display is performed. As such a light absorber 19, for example, a black film can be used. Alternatively, a black paint such as black ink may be applied to the lowermost surface of the display element to form the light absorber 19.

In FIG. 1, the red display layer 11R shows a planar state, the green display layer 11G shows a focal conic state, and the blue display layer 11B shows a state where both the planar state and the focal conic state coexist.

(Various Materials of Display Element) As the transparent substrate 12, a colorless and transparent glass plate or a transparent resin film can be used. Examples of the material of the transparent resin film include polyarylate resin, polyether sulfone resin, polycarbonate resin, norbornene resin, amorphous polyolefin resin, and modified acrylate resin. The characteristics of resin film are high translucency, no optical anisotropy, dimensional stability, surface smoothness, friction resistance, bending resistance, high electrical insulation, chemical resistance, liquid crystal resistance, heat resistance , Moisture resistance, gas barrier properties, etc. are required.

As the transparent electrodes 13 and 14, transparent electrodes such as ITO and Nesa films can be used, and those formed on the transparent substrate 12 by a sputtering method or a vacuum evaporation method are used. Further, as the transparent electrode 14 in the lowermost layer, a black electrode can be used including the role as a light absorber.

As the liquid crystal 16, a liquid crystal exhibiting a cholesteric phase at room temperature is particularly preferable. Further, a chiral nematic liquid crystal obtained by adding a chiral dopant to a nematic liquid crystal can be used.

The nematic liquid crystal has rod-shaped liquid crystal polymers arranged in parallel, but does not have a layered structure. As the nematic liquid crystal, various single liquid crystals such as a biphenyl compound, a tolan compound, a pyrimidine compound, and a cyclohexane compound, or a mixed liquid crystal thereof can be used.
Those having a positive dielectric anisotropy are preferred. Specifically, a liquid crystal K15 mainly containing a cyanobiphenyl compound is used.
, M15, mixed liquid crystal MN1000XX (all manufactured by Chisso), E44, ZLI-1565, TL-213, B
L-035 (all manufactured by Merck).

The chiral dopant is an additive having a function of twisting the molecules of the nematic liquid crystal when added to the nematic liquid crystal. By adding a chiral dopant to a nematic liquid crystal, a helical structure of liquid crystal molecules having a predetermined twist interval is generated, thereby exhibiting a cholesteric phase.

The chiral nematic liquid crystal has the advantage that the pitch of the helical structure can be changed by changing the addition amount of the chiral dopant, thereby controlling the selective reflection wavelength of the liquid crystal. In addition,
In general, as a term representing the pitch of the helical structure of liquid crystal molecules, a “helical pitch” defined by a distance between molecules when the liquid crystal molecules rotate 360 degrees along the helical structure of the liquid crystal molecules is used.

As the chiral dopant, those having a nematic liquid crystal molecule having a layered helical structure can be used. For example, it is a nematic liquid crystal such as a biphenyl compound, a terphenyl compound or an ester compound. Specifically, commercially available chiral dopants S811, CB1 obtained by bonding an optically active group as a terminal group of the compound.
5, S1011, CE2 (all manufactured by Merck) and the like can be used. A cholesteric liquid crystal having a cholesteric ring represented by cholesteric nonanoate (CN) can also be used as a chiral dopant.

As the chiral dopant to be added to the nematic liquid crystal, plural kinds of chiral dopants may be mixed and used, and in addition to the combination of the same kind of optical rotation, a combination of different kinds of optical rotation can also be used. The use of multiple types of chiral dopants can change the phase transition temperature of cholesteric liquid crystals, reduce the change in the selective reflection wavelength in response to temperature changes, and also provide dielectric anisotropy, refractive index anisotropy and viscosity. And other properties of the cholesteric liquid crystal can be changed, thereby improving the characteristics of the display device.

Materials used for the columnar structure 15 include:
For example, a thermoplastic resin can be used. For this purpose, a material which is softened by heating and solidified by cooling, is desired not to cause a chemical reaction with a liquid crystal material to be used and to have appropriate elasticity.

As specific examples, for example, polyvinyl chloride resin, polyvinylidene chloride resin, polymethacrylate resin, polyacrylate resin, polyvinyl acetate resin, polystyrene resin, polyamide resin, polyethylene resin, polypropylene resin, fluorine Resins, polyurethane resins, polyacrylonitrile resins, polyvinyl ether resins, polyvinyl ketone resins, polyvinyl pyrrolidone resins, polycarbonate resins, chlorinated polyether resins, and the like. These may be used alone or in combination, or the columnar structure 15 may be formed from a material containing at least one or a mixture of these.

The substance is printed by a known printing method using a pattern so as to form dot columns. Depending on the size of the liquid crystal display element and the pixel resolution, the size of the cross-sectional shape, arrangement pitch, and shape (cylinder, drum, polygon, etc.)
Is appropriately selected. Further, it is more preferable to arrange the columnar structures 15 preferentially between the electrodes 13 because the aperture ratio is improved.

The shape may be a stripe shape instead of a dot shape, and may be selected according to the purpose. Further, in order to improve the accuracy of the gap control between the substrates 12, the columnar structures 15
When forming a spacer material having a size smaller than the thickness of the resin, for example, glass fibers, ball-shaped glass or ceramic powder, or spherical particles made of an organic material, the gap is changed by heating or pressing. If it is made difficult, gap accuracy is further improved, and voltage unevenness, color unevenness and the like can be reduced.

(Display of Color) In the color display layers 11R, 11G, and 11B using such a chiral nematic liquid crystal, when the selective reflection wavelength of the cholesteric liquid crystal is in a visible light region, the helical axis of the cholesteric liquid crystal molecule is set on the substrate surface. In the focal conic arrangement state which is almost parallel to the visible light, the light is slightly scattered with respect to incident visible light, but is almost transparent. Also,
In a planar arrangement state in which the helical axis of the cholesteric liquid crystal molecules is substantially perpendicular to the substrate surface, light having a wavelength corresponding to the helical pitch is selectively reflected with respect to incident visible light. These two states can be switched by a change in a field such as a predetermined electric field, magnetic field, or temperature. Even when the field disappears, each state is maintained, that is, it has a memory property.

When a chiral nematic liquid crystal is used from the above characteristics, the amount of the chiral dopant to be added to the nematic liquid crystal is adjusted so that the helical pitch of the chiral nematic liquid crystal can be adjusted by the selective reflection wavelength.
By adjusting the wavelengths to correspond to the red, green, and blue light, respectively, it selectively reflects light in the wavelength ranges corresponding to red, green, and blue, respectively, in the planar arrangement state, In the state of alignment, a liquid crystal material which is transparent and transmits visible light can be obtained. By sandwiching the thus obtained liquid crystal material between the transparent electrodes, a color liquid crystal display element can be obtained.

(Addition of Dyes for Improving Color Purity and Contrast, Arrangement of Color Filters)
In R, 11G, and 11B, in order to improve the color purity of the display performed by selective reflection and to absorb a light component that leads to a decrease in the transparency in the transparent state, a dye is added to each color display layer, or a dye equivalent thereto is added. A colored filter layer that provides an effect, that is, a plate member such as a color glass filter or a color film may be provided on each color display layer. The dye may be added to any of the liquid crystal material, the resin material, the transparent electrode material, and the transparent substrate material constituting each color display layer, and a plurality of the constituent elements may contain the dye. However, in order not to lower the display quality, the dye to be added and the filter layer to be added are:
It is desirable not to hinder color display by selective reflection of each color display layer.

As the dye to be added to the liquid crystal material, conventionally known various dyes can be used. For example,
Various dyes such as resin dyes and liquid crystal display dichroic dyes can be used. Specific examples of the dye for resin dyeing include SPR-Red1 and SPR-Yellow1.
(All manufactured by Mitsui Toatsu Dye Co., Ltd.). Further, specific examples of the dichroic dye for liquid crystal display include SI-426,
M-483 (all manufactured by Mitsui Toatsu Dye Co., Ltd.). Among these dyes, a dye that does not hinder display by the selective reflection wavelength of the liquid crystal and absorbs spectral light in a wavelength region that causes a reduction in display may be appropriately selected and used for each color display layer. Further, as described above, since the light component that degrades the display quality is considered to be mainly present on the short wavelength side, the dye that absorbs the spectrum light in the wavelength range shorter than the selective reflection wavelength of the liquid crystal. Is more preferably used.

The amount of the dye to be added is not particularly limited as long as the switching operation characteristic for displaying the liquid crystal is not remarkably reduced.
It is preferable to add the above, and about 1% by weight is sufficient.

When a color filter is employed in place of the addition of a dye, an additional filter layer material may be a colorless and transparent substance to which a dye is added. It may be a material that is inherently colored without adding a dye, or a thin film of a specific substance that functions similarly to the dye. Specific examples of the filter layer include commercially available colored glass filters and Wratten gelatin filter Nos. 8, no. 25 (all manufactured by Eastman Kodak Co.) can be used. Of course, instead of disposing the filter layer, the transparent substrate 12
It is clear that the same effect can be obtained even if the filter itself is replaced with the above-mentioned filter layer material.

(Method of Color Display) In the liquid crystal display element 10 in which the respective color display layers 11R, 11G, 11B manufactured with the above-described material constitutions are laminated, the blue display layer 11B and the green display layer 11G are formed by the liquid crystal 16 being focal. A red display can be performed by setting the transparent state in the conic arrangement and the selective reflection state in which the liquid crystal 16 has the planar arrangement in the red display layer 11R. Further, the blue display layer 11B is set in a transparent state in which the liquid crystal 16 is in a focal conic arrangement, and the green display layer 11G and the red display layer 11R are
Is set in the selective reflection state in which the elements are in a planar arrangement, so that yellow display can be performed. Similarly, red, green, blue, white, cyan, magenta, yellow, and black can be displayed by appropriately selecting the state of each color display layer between a transparent state and a selective reflection state. Further, by selecting an intermediate selective reflection state as the state of each color display layer 11R, 11G, 11B, display of an intermediate color becomes possible, and it can be used as a full-color display element.

Each color display layer 11 in the liquid crystal display element 10
The order of lamination of R, 11G, and 11B may be other than that shown in FIG. However, considering that the transmittance of the light in the long wavelength region is higher than that in the short wavelength region, the selective reflection wavelength of the liquid crystal contained in the upper layer is changed to that of the liquid crystal contained in the lower layer. It is better to keep it shorter than the wavelength
Since more light is transmitted to the lower layer, a bright display can be performed. Therefore, it is most desirable to sequentially form the blue display layer 11B, the green display layer 11G, and the red display layer 11R in order from the observation side (the direction of arrow A), and this state provides the most preferable display quality.

(Production Example of Liquid Crystal Display Element) The resin columnar structure 15 is formed on the upper substrate 12 by the printing method. FIG. 2 shows the upper substrate 12 in this state. here,
The resin film as the substrate is PES (polyether sulfone: manufactured by Tomo Bakelite Co., Ltd.) of 20 μm, and a screen printing coater MS400 (manufactured by Murakami Co., Ltd.) having a dot pattern of polyvinyl chloride with a thickness of about 15 μm is further formed thereon. And printed.

On the resin film, an ITO thin film was formed in a belt shape with a thickness of 700 Å by a known sputtering method. Subsequently, a silicon oxide film was laminated to a thickness of 4000 angstroms using the same device to form an insulating film. Next, the temperature of the resin film was adjusted to 25 ° C., and a sealing material 17 was printed around the thermoplastic polyester resin using the screen printing applicator MS400. After printing, the whole is 80 ° C on a hot plate,
Heating was performed for 20 minutes, and the solvent contained in the columnar structure 15 and the sealing material 17 was dried. As a result, a columnar structure 15 having a diameter of 35 μm, a height of 10 μm, and a pitch of 300 μm, and a sealing material 17 having a width of 1 mm and a height of 10 μm were formed.

Next, SE-610 was used as an alignment control material.
(Manufactured by Nissan Chemical Industries, Ltd.) by a known spin coating method to about 50
It was applied to a thickness of 0 Å and heated at 180 ° C. for 1 hour.

Next, another PES serving as a lower substrate
(Same as the upper side) is prepared, and the strip-shaped transparent electrode surface is superimposed on the upper side film, and the liquid crystal 16 is dropped between the two films 12 by the apparatus shown in FIG.
The liquid crystal 16 was sealed while heating and pressing with. However, at this stage, the sealing region at the end was opened without heating and pressing so that excess liquid crystal could be discharged to the outside.

Next, the two superimposed films 12 were sandwiched between two stainless steel flat plates to obtain 0.37 kg / cm.
^With a load of ² applied, the film 12 was left in a thermostat at 160 ° C. for 1 hour, and the entire surface of the film 12 was bonded. Thereafter, the power of the thermostat was turned off, and the chamber was cooled to room temperature while applying a load.
Ultraviolet-curable resin Photolec A-704-60 (manufactured by Sekisui Fine Chemical Co., Ltd.) was applied to the peripheral portions of both films 12 and irradiated with ultraviolet light to complete the sealing.

As a liquid crystal material, MLC6068-00 is used.
No. 0 (a nematic liquid crystal material manufactured by Merck) and 2.4 wt% of a chiral material S-811 (manufactured by Merck) were added. Using the cholesteric liquid crystal display device thus manufactured, a full-color liquid crystal display device 10 was manufactured.

(Driving Circuit and Driving Method of Display Element) Since the pixel configuration in each display layer of the liquid crystal display element 10 is a simple matrix, as shown in FIG.
1, R2 to Rm and an m × n matrix of signal electrodes C1, C2 to Cn. A pixel at the intersection of the scanning electrode Ra and the signal electrode Cb (a and b are natural numbers satisfying a ≦ m and b ≦ n) is defined as LCa-b. Further, these electrode groups are respectively a scan drive IC 21 and a signal drive IC 22.
Of the driving ICs 21 and
From 22, a scanning voltage and a selection voltage are applied to each electrode.

The driving circuit of the liquid crystal display element 10 is not limited to the matrix-structured driver, but the signal driving IC is provided for each line of the scanning driving IC 21.
The image data may be transferred serially from 22 via a line latch memory. In this case, the scanning drive IC 21 is not line-compatible, but needs to be for serial use, and the cost of the driver is low.

Hereinafter, this driving circuit will be described. FIG. 5 shows voltage waveforms applied to the respective scanning electrodes and signal electrodes, and the resulting voltage waveforms applied to the liquid crystal. Waveform (a),
(B) and (c) show voltage waveforms applied to the scanning electrodes R1, R2, and R3, respectively. Waveforms (d), (e)
Indicates voltage waveforms applied to the signal electrodes C1 and C2, respectively. Waveform (f) shows scanning electrode R3 and signal electrode C1.
Shows the voltage waveform applied to the liquid crystal constituting the pixel LC3-1 that intersects. This waveform (f) is 300 (1)
To 300 (m), 301, and 302. The total of 300 (1) to 300 (m) is referred to as a scanning period, 301 is referred to as a reset period, and 302 is referred to as a display period.

In the reset period 301, each of the scan electrodes R1 to R1
A voltage VF and a pulse voltage having a pulse width t1 are applied to Rm. This pulse voltage is called a scan reset signal. In the reset period 301, no voltage is applied to each of the signal electrodes C1 to Cn. The signal applied to the signal electrode during the reset period 301 is called a data reset signal, and the voltage is 0 in this example. By applying the scan reset signal and the data reset signal, a pulse voltage having a voltage VF and a pulse width t1 is applied to the liquid crystal constituting all the pixels during the reset period 301. This pulse voltage is called a reset signal.

Next, in the scanning period 300 (3),
The liquid crystal forming the pixel on the scanning electrode R3 is rewritten. At this time, the scan electrode R3 to be rewritten is called a scan selection electrode, and the other scan electrodes are called scan non-selection electrodes. 300 (3) is referred to as a scan selection period of the scan electrode R3. During the scan selection period of the scan electrode R3, a pulse voltage having a voltage Vr and a pulse width t2 is applied to the scan electrode R3. This pulse voltage is called a scan selection signal. At the same time, a pulse voltage of voltage Vc1 (3) and pulse width t2 is applied to the signal electrode C1. The pulse voltage applied to the signal electrode is called a data signal. By applying the scan selection signal and the data signal, the scan selection electrode R3 and the signal electrode C1 are applied.
Is applied to the liquid crystal LC3-1 at the position where the voltage Vr-
A pulse voltage of Vc1 (3) and pulse width t2 is applied. This pulse voltage is called a selection signal.

During the scanning period, 300 (1), 300
(2), 300 (4) to 300 (m) have the scanning electrode R3
Is selected as a scanning non-selection electrode. 300 (1), 300
(2), 300 (4) to 300 (m) are referred to as a non-selection period of the scanning electrode R3. No voltage is applied to the scan electrode R3 during the non-selection period of the scan electrode R3. Here, the voltage is 0, but this pulse voltage is referred to as a scanning non-selection signal. The voltage of the pulse width t2 is applied to the signal electrode C1 by V
c1 (1), Vc1 (2), Vc1 (4) to Vc1
The data signal of (m) is applied. By applying the scanning non-selection signal and the data signal, the liquid crystal LC3 at the position where the scanning non-selection electrode R3 intersects with the signal electrode C1.
-1 has voltages -Vc1 (1), -Vc1 (2), -Vc
A pulse voltage of 1 (4) to -Vc1 (m) and a pulse width t2 is applied. This pulse voltage is called a non-selection signal.

In the display period 302, each of the scanning electrodes R1 to Rm
And no voltage is applied to each of the signal electrodes C1 to Cn. The pulse voltage at this time is called a display maintaining signal.

In the liquid crystal display element 10, the display state of the liquid crystal is a function of the applied voltage and the pulse width. When a pulse voltage having a constant width is applied to the liquid crystal after first resetting the liquid crystal to a focal conic state showing the lowest Y value (luminous reflectance), the display state becomes as shown in FIG. Changes. 6, the vertical axis indicates the Y value, and the horizontal axis indicates the applied voltage. When the pulse of the voltage Vp is applied, the planar state showing the highest Y value is selected, and the voltage Vf
Is applied, the focal conic state showing the lowest Y value is selected. When an intermediate voltage is applied, a state in which the planar state and the focal conic state exhibiting an intermediate Y value are mixed is selected, and halftone display becomes possible.

Vf is a voltage value that brings the liquid crystal to the focal conic state most when applied for a relatively short time. On the other hand, VF is a voltage value that brings the liquid crystal to the closest focal conic state when applied for a relatively long time. Generally, Vf> VF.

Hereinafter, the meaning of each signal will be described. The reset signal applied to the liquid crystal in the reset period 301 is applied simultaneously to the liquid crystal constituting all the pixels, and the display state of all the pixels is set to the focal conic state. The voltage VF is a voltage for bringing the cholesteric liquid crystal into a focal conic state. Preferably, the pulse width t1 is set to a sufficiently long time. This is because the liquid crystal slowly changes to the focal conic state even when the voltage VF is applied. Therefore, unless a voltage is applied for a sufficiently long time, the liquid crystal is affected by the state before the voltage and all the pixels do not uniformly enter the focal conic state. is there. Depending on the required number of tones and cell configuration, for example,
t1 can be set in a range of about 100 ms to 1 s.

During the scanning period, a selection signal and a non-selection signal are applied to the liquid crystal. The voltage setting of each signal is as follows. During a selection period of a certain scan electrode Ri (i is an integer of 1 to m), a scan selection signal having a voltage Vr = Vp and a pulse width t2 is applied to the scan electrode Ri, and a voltage is applied to a certain signal electrode Cj (j is an integer of 1 to n). Vcj (i) and a data signal having a pulse width t2 are applied. Further, during the non-selection period of the scanning electrode Ri, the scanning electrode Ri
No voltage is applied to. In this manner, the liquid crystal constituting the pixel where the scanning electrode Ri and the signal electrode Cj intersect during the selection period of the scanning electrode Ri is supplied with the voltage Vr-Vcj (i), that is, the voltage Vp- with the pulse width t2. Vcj (i)
Are applied. Vcj (i) is changed from 0 to Vp
When a selection is made from -Vf, a selection signal having a pulse width t2 and a voltage of Vp to Vf is applied to the liquid crystal, and an arbitrary display state can be selected.

In the non-selection period of the scanning electrode Ri, the voltage of the liquid crystal constituting the pixel on the scanning electrode Ri is changed from 0 to V.
A non-selection signal of p-Vf is applied. The liquid crystal to be driven in the present invention has memory characteristics, and the display state does not change at a voltage lower than a certain threshold voltage. Therefore, if the non-selection signal is kept below a predetermined threshold voltage, the display state of the liquid crystal is maintained. In order to select the display state of the liquid crystal constituting all the pixels, the scanning electrodes Ri are sequentially scanned from 1 to m.

In the display period, no voltage is applied to the liquid crystal,
Maintain the display state stored in memory. That is, the voltage applied to the scanning electrode and the signal electrode is set to 0, and no voltage is applied to the liquid crystal.

The time required for rewriting the entire screen is t1 + m × t2 because it is the reset period plus the scanning period. Since the time for selecting the focal conic state is longer than the time for selecting the planar state, t1 >> t2. Therefore, even if the number of pixels increases, the long reset period does not increase, so that high-speed rewriting can be performed. The driving mode as described above is referred to as a still image mode.

FIGS. 7A and 7B show waveforms (a) and (b) of pulse voltages applied to the liquid crystal of the test cell prototyped by the present inventors. Here, only the selection signal is applied from the signal electrode during scanning with respect to only one pixel. The voltage of the reset signal was 50 V, the pulse width (reset time) was 200 ms for the wavelength (a), and 50 ms for the wavelength (b).
Then, a selection signal for setting the liquid crystal to the planar state was applied at a voltage of 90 V-Vc for 5 ms.

As shown in the waveform (a), when the reset signal is applied for 200 ms, the selection signal is applied regardless of whether the liquid crystal state before reset is in the planar state or the focal conic state. A good planar state was obtained, and gradation expression when the voltage value of the selection signal was changed was also possible. On the other hand, as shown in the waveform (b), when the reset signal was applied for 50 ms, the liquid crystal was not always sufficiently reset, and the Y value when the liquid crystal was set to the planar state thereafter varied.

It has been found from the above experiments that the longer the reset signal application time is, the less likely it is to be affected by the state before rewriting, and that if the time is sufficiently long, the desired display state can be rewritten irrespective of the state before rewriting. It is. In other words, by applying the reset signal for a sufficiently long time,
No longer affected by the previous state. In the waveform (a), it was found that the display time of about 4 gradations was possible when the reset signal application time was 200 ms. However, when the reset signal of 200 ms or more was applied, the selected display state depending on the difference in the initial state And the display of four or more gradations becomes possible.

(Driving Method) FIG. 8 shows the liquid crystal display element 1
The pulse voltage applied to each of the electrodes 13 and 14 for driving the zero is shown. After applying a reset signal of 50 V for 200 msec, a selection signal of 150 V is applied to one pixel for 1 ms.
ec is applied N times. The number of times N is arbitrary, and when driven at N = 2, an image can be displayed in a shorter time than in the still image mode, although the contrast is low. If this is displayed in the order of the pages of the image stored in advance, it is possible to display that the pages of the book are flipped, and such driving is referred to as a fast-forward mode. On the other hand, the contrast may be increased each time a voltage is applied by setting N = 4, and a final image of full contrast may be displayed by applying the fourth pulse voltage. In this case, an expression similar to fade-in is possible. If an image can be grasped in the middle of the fade-in, an instruction to display the next page is input, and if the display is switched to the next page, the same usage as in the fast forward mode is eventually achieved.

FIG. 9 shows an information display device 1 according to an embodiment of the present invention including a drive / image signal processing circuit 20 adapted to rewrite image data. The scanning drive IC 21 and the signal drive IC 22 are connected to the liquid crystal display element 10, and these ICs 21 and 22 are connected to the scan controller 2 respectively.
3. Driven by a control signal from a signal controller 24 incorporating a time counter. Image data to be newly displayed is input from the memory 26 to the signal controller 24, but is converted into a selection signal by the image data conversion means 25 before that.

The time counter counts the timing of rewriting the image on the liquid crystal display element 10 when the fast-forward mode is selected. The memory 26 stores image data of a plurality of pages, and outputs the image data displayed at a timing based on the count of the time counter in the order of pages. The memory 26 stores image data transferred from the CPU 33 described below.

FIG. 10 shows an example of a control procedure for driving the liquid crystal display element 10. As shown in FIG. 5, this control includes a reset period (first period), a scanning period (second period), and a display period (third period). Period and display period are repeated multiple times. Then, when a predetermined image is displayed or when the observer inputs a reset request, the screen is reset. The image data used here is binary.

First, the liquid crystal display element 10 is reset in step S1. At this time, it is displayed in black as shown in the display state 1. When there is a write request for the character "A" in step S2, the character "A" is written in step S4 (see display state 2). When there is a write request for the character "B" in step S5, the character "AB" is written in step S7 (see display state 3). Further, in step S8, the character "
If there is a write request of "C", in step S10 the character "
ABC ”is written (refer to display state 4). If there are any more characters to be displayed, a write request is subsequently performed, and
Desired characters are sequentially displayed on the liquid crystal display element 10 by one reset. In this case, the newly added image (character) data is based on the image (character) data synthesized so as not to overlap the already displayed image (character) data, ie, the liquid crystal display element 10, that is, the scanning electrode 13 and the The signal electrode 14 is driven.

When a full screen reset request is made in step S11, the process returns to step S1 to perform reset processing.
The full screen reset request is performed when a predetermined image (character) is displayed on the display element 10 after the desired number of times of writing has been executed, or when an observer inputs a reset request.

In the above control means, the display states 1 and
The period in which 2, 3, and 4 are displayed is a period until a write request or a reset request is made (steps S3, S6, S
9, S12), and the display in step S12 is maintained until a full screen reset request is made. If there is a reset request in step S11, the liquid crystal display element 1
On the screen 0, images (characters) of the next page are sequentially displayed.

FIG. 11 shows a control procedure for displaying a multi-valued color image like fade-in using the driving method shown in FIG. In this control, the selection pulse signal is applied four times, the contrast is improved each time, and a complete color image is displayed by applying the fourth selection pulse signal. In addition, when a signal to display another image is input during application of the pulse signal four times, the screen is switched to another image screen (fast forward mode).

First, in step S21, the liquid crystal display element 10
Reset. Next, the first write is performed in step S22, and as shown in FIG.
/ 4 image is displayed. Subsequently, steps S24 and S
At 26 and S28, the second, third, and fourth writings are performed, and images with sequentially improved contrast are displayed as shown in FIGS. 13, 14, and 15, respectively.

On the other hand, when a request to write another image is input during the writing of each image (steps S23 and S2).
5, S27, S29), returning to step S21 to perform a reset process, and display an image of the next page. The input of the request to write another image here is performed at an appropriate time by turning on a fast-forward key (not shown) when the observer wants to view another image quickly.

FIG. 16 shows a circuit configuration in which only a portion changed when information is rewritten can be partially rewritten. Since the liquid crystal display element 10 has memory characteristics, partial rewriting is possible.

First, the current image data is stored in the image memory 1. The image data to be newly displayed is stored in the image memory 2. Line memory 1 has image memory 1
, Data per scanning electrode is read out and stored. In addition, data is similarly read from the image memory 2 and stored in the line memory 2. This line memory 1,
The data of No. 2 is compared by the comparing means, here the comparator 41, and the line numbers which do not match are stored in the address storage means. In this way, only the part that changes from the current image is extracted for each scanning electrode, and is set as a rewriting target.

A predetermined time is set in advance in a time counter built in the controller 24, and when this time has elapsed, the scanning controller 23 and the data signal controller 24 store the address stored in the address storage means 42. Referring to FIG. 3, the control signal is supplied to the scanning signal driving IC 2 so that only the liquid crystal on the corresponding scanning electrode is rewritten.
1. Output to the data signal drive IC 22. As a result, the scanning signal driving IC 21 and the data signal driving IC 22 drive only the liquid crystal to be rewritten. According to such a driving method, only the portion to be rewritten can be rewritten, and display can be performed faster than rewriting the entire screen.

(Information Display Device) FIG. 17 shows a portable electronic book type information display device 40 in which the liquid crystal display element 10 is disposed on the left and right sides of a cover 45 which can be folded at a central portion 46.
Is shown. Here, the element 10 on the left is screen 1 and the element 10 on the right is screen 2. In the fast-forward mode, the images are displayed sequentially on screens 1, 2, 1, 2,. in this case,
Screens 1 and 2 are largely divided into upper and lower parts. First, the upper half is reset, and images A and B are displayed by the driving method shown in FIG. 8, respectively. The display of the image C in the lower half is started by the driving method shown in FIG. Next, the next image is similarly displayed in the lower half of the screen 2. When the image A is completed, it is erased and the next image is written in the erased portion. By displaying images sequentially using two screens in this way, the fast-forward mode can be executed at a higher speed.

FIG. 18 also shows an information display device 40 in the same electronic book form as FIG. Here, screens 1 and 2 are divided into left and right, respectively, and images A, B, C,.
Are sequentially displayed by the driving method shown in FIG.

In FIGS. 17 and 18, reference numeral 43 denotes a power switch, and reference numeral 44 denotes a group of operation keys, of which an operation key 44a is a fast-forward mode selection key. This key 44
When a is turned on, the fast forward mode is executed, and when it is turned on again, it returns to the normal still image mode.

(Light Amount Compensation) In the liquid crystal display element 10, the amount of reflected light on the screen decreases at night or in a dark room. Therefore, as shown in FIG. 19, a front light 47 and a diffusion plate 48 for compensating the amount of reflected light are provided on the front surface of the liquid crystal display element 10. Front light 47 on,
The turning off or the adjustment of the light amount is controlled based on the detection result of the light receiving sensor 49 shown in FIGS. If the detected light amount is equal to or less than the predetermined value, the light amount of the front light 47 is increased, and if the detected light amount exceeds the predetermined value, the light amount of the front light 47 is fixed to a relatively low constant value or the light 47 is turned off. Such light amount compensation is not limited to the electronic book type, but can be applied to a wall-mounted display element 10 shown in FIG.

Further, a temperature sensor is provided in place of the light receiving sensor 49. When the temperature detected by the temperature sensor exceeds a predetermined value, the currently displayed screen is reset once, and the driving voltage at the time of writing is reset. Also rewrite at a lower voltage. The contrast of the liquid crystal used in the present embodiment becomes too large as the temperature rises. Therefore, it is preferable to recover the contrast that has become too large due to the temperature rise. A change in contrast due to a temperature change has a large adverse effect in the fast-forward mode, and is effective in the fast-forward mode.

FIG. 20 shows an example of a display method of the liquid crystal display element 10. Here, the screen of the display element 10 is divided into an image information area 10a and a character information area 10b, and the image information area 10a is displayed in the fast-forward mode by the driving method shown in FIG. Usually, it is considered that the image information has a larger information amount than the character information, and the information can be easily specified. Therefore, when image information and character information are mixed on one screen, even if the image information has a low contrast, the image information is preferentially displayed in the fast forward mode, the image to be displayed is determined, and then the corresponding character information is displayed. Is displayed.

(Information Display System) FIG. 21 shows a first example of an information display system using the information display device 40. In this system, an information display device 40 and a host device 50 are combined into an electronic book form shown in FIGS. The host device 50 includes the signal processing unit 5
2, a controller 53, a driver 54 and a power supply 55. The information recording medium 51 is a card type memory,
The storage medium is a well-known recording medium such as a CD-ROM or a magnetic memory, and is purchased or rented from a store such as a convenience store by a user and inserted into the host device 50. The information data from the inserted information recording medium 51 is input to the signal processing unit 52.

The information display device 40 shown in FIG. 21 is constituted by the circuit shown in FIG. Here, the host device 50
Receiving the information data transferred from the driver 54 of the receiving circuit 3
1 and input to the CPU 33 via the demodulation circuit 32 and further stored in the memory 35. The display of information on the liquid crystal display element 10 is performed by reading data from the memory 35 and driving the display element 10 by the drive / image signal processing circuit 20. The power supply unit 36 supplies power to various circuits in the display device 40.

FIG. 23 shows a second example of the information display system. This system is an electronic book type information display device 40.
And the host device 50 ′, and one host device 5
The information data can be transferred from 0 'to a plurality of information display devices 40.

The host device 50 'has an IRDA (infrared communication means) 56 at its output section, and transfers information data to the information display device 40 by remote control. In this system, for example, if a host device 50 'is installed in one room of a building, information can be transferred to the information display devices 40 at a plurality of locations. That is, a plurality of users can view information of the same source. In addition, IRDA5
Instead of 6, other communication means such as a frequency modulation communication means may be used.

(Information Display Device with Speaker) FIG.
The information display device 40 'provided with the speaker 61 is shown. The speaker 61 has a film shape and is provided below the liquid crystal display element 10. Further, the host device 50 shown in FIG. 21 is also incorporated in the device 40 ', and the information recording medium 51 is inserted. Further, an operation unit 62 for volume control and information display is installed integrally with the power supply unit and the like. The speaker 61 plays audio information stored in the medium 51 in advance. In the fast-forward mode, display information can be supplemented with audio information. Also, the audio may be fast-forwarded in synchronization with the fast-forward of the screen. Note that the headphones 6
3 may be provided instead of the speaker 61, or may be provided together.

(Bending System) FIG.
7, a first example of a bending system for supplying an information recording medium 51 to a user having the information display device 40 shown in FIG. The information recording medium 51 is manufactured by a publisher or the like as an electronic information maker, and is brought into a convenience store, which is a store, via a dedicated cable, dedicated communication using radio waves, or a maintenance man.
The user can select the desired recording medium 5 at the convenience store.
You will either buy or rent one. The user may store desired information in the display device 40 owned by the user at the convenience store.

FIG. 26 shows a second example of the bending system. In this vending system, an electronic information maker transfers information ordered by a user after viewing a catalog or the like to a user's personal computer 75 via a cable (telephone line). The user outputs the information transferred on the screen of the personal computer 75 or stores the information in the recording medium 51 owned by the user, and inputs the information to the information display device 40 via the recording medium 51. In addition, the electronic information maker that has received the order is
1 may be delivered directly to the user.

(Other Embodiments) The information display device and the information display system according to the present invention are not limited to the above embodiments, but can be variously modified within the scope of the invention. In particular, specific examples and numerical values of various materials such as a liquid crystal are merely examples. Further, there are various usages and display contents of the display device or the system, and an optimum control method may be adopted.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a liquid crystal display element used in an information display device or an information display system according to the present invention.

FIG. 2 is a plan view showing a state in which a columnar structure and a sealing material are formed on a film substrate of the liquid crystal display element.

FIG. 3 is an explanatory view showing a manufacturing process of the liquid crystal display element.

FIG. 4 is a block diagram showing a matrix drive circuit of the liquid crystal display element.

FIG. 5 is a chart showing a voltage waveform applied to the matrix driving circuit.

FIG. 6 is a graph showing a relationship between a voltage applied to a selection signal and a Y value in the matrix driving circuit.

FIG. 7 is a chart showing a voltage waveform experimentally applied to a test cell.

FIG. 8 is a chart showing a voltage waveform applied in a fast-forward mode.

FIG. 9 is a block diagram showing a driving / image signal processing circuit used in an embodiment of the present invention.

FIG. 10 is a flowchart illustrating an example of a control procedure of the liquid crystal display element.

FIG. 11 is a flowchart showing another example of the control procedure of the liquid crystal display element.

FIG. 12 is a diagram showing an image written for the first time in the control procedure shown in FIG. 11;

FIG. 13 is a view showing an image written for the second time in the control procedure shown in FIG. 11;

FIG. 14 is a view showing an image written for the third time in the control procedure shown in FIG. 11;

FIG. 15 is a view showing an image written for the fourth time in the control procedure shown in FIG. 11;

FIG. 16 is a block diagram showing another example of the drive circuit of the liquid crystal display element.

FIG. 17 is a plan view showing an example of an information display device in an electronic book form.

FIG. 18 is a plan view showing another example of the information display device in the form of an electronic book.

FIG. 19 is a schematic side view showing an example in which a front light is attached to the information display device.

FIG. 20 is an explanatory diagram illustrating an example of a display method on a liquid crystal display element.

FIG. 21 is a block diagram showing a first example of an information display system according to the present invention.

FIG. 22 is a block diagram showing a control circuit incorporated in the information display device shown in FIG. 21;

FIG. 23 is a block diagram showing a second example of the information display system according to the present invention.

FIG. 24 is a plan view showing an information display device incorporating a speaker.

FIG. 25 is an explanatory diagram showing a first example of a recording medium bending system.

FIG. 26 is an explanatory diagram showing a second example of a recording medium bending system.

[Explanation of symbols]

 1, 40, 40 'Information display device 10 Liquid crystal display element 12 Substrate 13 Scanning electrode 14 Signal electrode 16 Liquid crystal 20 Driving / image signal processing circuit 31 Receiving circuit 50, 50' Host device 61 Film speaker

Continued on the front page (72) Inventor Hideo Hotomi 2-13-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka International Building Minolta Co., Ltd. (reference) 2H093 NA14 NA43 NA51 NA61 NB02 NB03 NB09 NB10 NB13 NB14 NB23 NC10 NC12 NC13 NC27 NC28 NC37 NC55 ND02 ND32 NE01 NF17 NG01 NG20 5C006 AA02 AA03 AA22 AA28 AC02 AC15 AF05 BA12 BB11 BB28 BC12 BF05 BF14 FA12 5C080 AA10 BB05 CC03 DD08 EE01 EE17 EE12 A02 JJ30 EJ12 EJ30 JJ12 EJ30 JJ12 EJ30 JJ12 JJ30 EJ30 AA36 BA49 GA10 HA10

Claims (15)

[Claims] 1. A method of driving a reflection type liquid crystal display element having a memory property, wherein a signal pulse voltage for driving the liquid crystal display element is:
A method for driving a liquid crystal display element, wherein the method is set a plurality of times for at least one pixel. 2. A reflection type liquid crystal display element having a memory function, driving means for applying a pulse voltage for driving the liquid crystal display element, and a plurality of signal pulse voltages corresponding to information data for at least one pixel. An information display device comprising: control means for setting the number of times. 3. The information display device according to claim 2, further comprising a receiving means for receiving information data transferred from outside. 4. An information display device having a reflective liquid crystal display element having a memory function, wherein: a first operation mode for setting a single signal pulse voltage for each pixel to display one image; The signal pulse voltage for driving the display element is
An information display device comprising: a second operation mode that is set a plurality of times for at least one pixel; and a selection unit that selects the first and second operation modes. 5. The information display device according to claim 2, further comprising a film speaker. 6. A liquid crystal exhibiting a cholesteric phase at room temperature is sandwiched between a first substrate having a plurality of scanning electrodes and a second substrate having a plurality of signal electrodes, and the scanning electrodes and the signal electrodes are arranged in a matrix. A driving method of the opposing liquid crystal display element, wherein a first period in which the liquid crystal simultaneously applies a reset pulse voltage to take a first state to a predetermined number of scanning electrodes and signal electrodes;
A second period in which the state of the liquid crystal is changed by sequentially applying a scan pulse voltage to a predetermined number of scan electrodes and applying a signal pulse voltage corresponding to information data to the predetermined number of signal electrodes sequentially in synchronization with the scan pulse voltage; A third period in which a voltage applied to a predetermined number of scan electrodes and signal electrodes is set to 0 to maintain a display state, and the second and third periods are performed a plurality of times following the first period. Repeating, a method for driving a liquid crystal display element. 7. The method according to claim 6, wherein the first state is a focal conic state. 8. The method according to claim 6, wherein the predetermined number of scan electrodes is all scan electrodes. 9. The driving method of a liquid crystal display device according to claim 6, wherein the predetermined number of scanning electrodes is a continuous electrode group adjacent to the scanning electrodes. 10. When the second and third periods are repeated a plurality of times, the information to be displayed next is applied to the scanning electrode and the signal electrode based on information data synthesized so that the information to be displayed next does not overlap the currently displayed information. 10. The method of driving a liquid crystal display device according to claim 6, wherein a voltage is applied. 11. The method according to claim 10, wherein the information is binary image data. 12. The liquid crystal display element according to claim 6, wherein the number of repetitions of the second and third periods is set to a predetermined number. Drive method. 13. The method according to claim 12, wherein the information is multi-valued image data. 14. When a rewrite request signal is generated during the repetition of the second and third periods, the drive of the first period is performed again, and then the second and third periods are repeated a plurality of times. 14. The method according to claim 12, wherein
The driving method of the liquid crystal display element described in the above. 15. A first operation mode in which the first period, the second period, and the third period are sequentially executed, and a second operation mode in which the driving method according to claim 6 is executed can be selected. A method for driving a liquid crystal display element.