JP2013200354A - Driving method of image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of achieving display in an intermediate density without impairing quality of an image, and selectively driving different types of particles in the case of simple matrix driving of an electrophoresis display.SOLUTION: Provided is a driving method of an image display device in which micro capsules including white, black, or colored particles together with dispersant are arranged with a binder between electrodes each having at least one transparent side. An AC pulse voltage is applied to one electrode, and a DC voltage is applied to the other electrode so as to control the particles in the micro capsules.

Description

  The present invention relates to a driving method of an image display device using a dielectrophoresis phenomenon of particles encapsulated in microcapsules.

  In recent years, with the development of information equipment, information display has been made in various forms. As a display of variable information, a CRT (cathode ray tube), a liquid crystal display, and the like are mainly used. A light-emitting display typified by a liquid crystal display using a CRT or a backlight makes the viewer's eyes tired when used over a long period of time, and is not suitable for reading text or the like.

  On the other hand, a reflection type liquid crystal display that does not use a backlight has a problem that the darkness of the screen due to the use of a polarizing plate appears remarkably and the visibility is poor.

  The images displayed on these displays do not have memory characteristics, and have the disadvantage that they disappear as soon as the electrical energy supply is stopped.

  In addition, since liquid crystal displays require cell gap accuracy, they are manufactured using a glass substrate, and it is difficult to manufacture and inject cells using films. Not suitable for mass production.

  In the replacement of printed information such as newspapers, books, magazines, and posters, as well as displays for portable information devices such as PDAs and e-books that will become more widespread in the future, good visibility, low power consumption, and flexibility It is considered necessary to have sex.

  Conventionally, electrophoretic display devices and two-color ball display devices are known as non-light-emitting displays that satisfy these requirements to some extent.

  Many electrophoretic display devices using an electrophoretic phenomenon by applying an electric field to electrophoretic particles dispersed in a dispersion medium have been reported. (See Patent Document 1)

  However, in a structure in which an electric field is simply applied to a dispersion system in which electrophoretic particles are dispersed in a dispersion medium, display unevenness is likely to occur due to particle agglomeration and adhesion to electrodes, and it is difficult to obtain good display quality. It was.

  For this reason, there is also known a structure in which the dispersion system is discontinuously divided by arranging various spacers to stabilize the display operation (see Patent Document 2). It is extremely difficult to fill the particles, and it cannot be said that the aggregation of particles and the adhesion and fixation to the electrodes could be reduced.

  As means for solving this problem, a method is described in which a dispersion system in which electrophoretic particles are dispersed in a dispersion medium is enclosed in microcapsules. (See Patent Document 3)

  According to this method, the aggregation of particles and the phenomenon of adhesion to the electrode are eliminated, stable display operation becomes possible, and not only the dispersion loading process is remarkably improved, but also the microcapsules themselves are made into ink. This makes it possible to create a display device using a printing technique such as coating or patterning on a flexible substrate.

  Thus, while display devices using electrophoretic particles are compatible with increasing size and flexibility, existing technologies for driving liquid crystal displays such as TFTs are used as the technology for driving them. The current situation is.

  However, when performing dynamic driving such as a simple matrix that is commonly used in liquid crystal display, unlike a liquid crystal with a clear threshold, even if a pair of opposing electrodes are selected and a pixel is specified, it is not specified. There is a problem in display quality such that particles migrate in a slight change in voltage, and in the case of intermediate density display, it is very difficult to control with a voltage proportional to the density.

  As described above, an electrophoretic dispersion system in which a substance having a thixotropic property is added to the dispersion system in order to provide a pseudo threshold value in the electrophoretic display is known.

  For example, an example has been reported in which the threshold value is indirectly increased based on the interaction between particles to improve properties such as dynamic driving and display maintenance (see Patent Document 4), but the material design is complicated. There remains a problem that power consumption for driving increases.

  A method of apparently increasing the contrast at the time of dynamic driving by combining a display system having a weak threshold response such as electrophoretic particles and a light-emitting display system having a clear threshold response has been studied (patent) Reference 5) must sacrifice features such as display memory performance and electrophoretic display legibility.

  As described above, in a display system using electrophoretic particles, it is difficult to operate with a simple matrix structure used in liquid crystal or the like, and driving by an active element typified by TFT (see Patent Document 6) is mainly used. Development is underway.

  Low-price, thin electricity that can display a simple matrix structure or its modified segment display when trying to expand displays into fields where display panels have not been used so far, such as tags, cards, tools, and appliances. The demand for electrophoretic display media is also expected to grow significantly.

  In addition, a display system using electrophoretic particles, which has been mainly used for black-and-white display so far, has a strong demand for adding a color display since it may be a single color.

Japanese Utility Model Publication No. 62-038626 JP 59-034518 Japanese Patent Laid-Open No. 1-086116 JP 2002-040967 A JP 2002-507765 A JP 2000-221546 A

  The present invention has been made in view of the problems of the prior art, and the problem is that even when an electrophoretic display is driven in a simple matrix, electrophoretic particles are not used for pixels that do not require operation. Of an image display device that does not impair the image quality due to operation, or can display intermediate density (gradation expression) and selectively drive different types of electrophoretic particles (for example, colored particles). It is to provide a driving method.

  As means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that a microcapsule in which white, black, or colored particles are encapsulated together with a dispersion medium has a binder between electrodes at least on one side. A driving method of an image display device arranged together with an alternating-current pulse voltage on one electrode of the image display device in which microcapsules containing particles of different coloring and particle size are mixed, and the other A driving method of an image display device, wherein a DC voltage is applied to an electrode to control particles in a microcapsule.

  In addition, the invention according to claim 2 induces dielectrophoresis of particles with an alternating pulse voltage applied to one electrode, and gives an offset to the alternating pulse voltage waveform with a direct voltage applied to the other electrode. And a moving direction of the image display device.

  The invention according to claim 3 is characterized in that the moving distance of the particles is controlled by adjusting the number of pulses of the non-uniform AC pulse voltage to which an offset is applied, and the display density is adjusted. It is.

  The invention according to claim 4 is the frequency of the AC pulse voltage at which all of the plurality of particle types included in the microcapsule migrate, and only one type of the plurality of particle types included in the microcapsule migrates. An image display apparatus driving method characterized in that display is performed by combining frequencies of alternating pulse voltages.

  According to the first aspect of the present invention, in the display device in which the white, black, or colored particles are encapsulated with the dispersion medium, at least one side is disposed with a binder between the transparent electrodes. Drive that controls the particles in the microcapsule by applying an AC pulse voltage to one electrode and a DC voltage to the other electrode of a display device with a mixture of microcapsules containing particles of different particle sizes By providing the means, it has become possible to display with a simple matrix electrode, which has been difficult to drive.

  Further, according to the invention described in claim 2, by inducing the dielectrophoresis of particles with an AC pulse voltage applied to one electrode and applying an offset to the AC pulse voltage waveform with a DC voltage applied to the other electrode, This makes it easy to control the direction of particle movement when driven by a simple matrix electrode, which is difficult to drive.

  According to the third aspect of the invention, the gradation expression of the display can be set in detail by controlling the moving distance of the particles according to the number of pulses of the non-uniform AC pulse voltage to which the offset is applied and adjusting the density of the display. It became so.

  In addition, according to the invention of claim 4, when the AC pulse voltage applied to the microcapsule exceeds a certain frequency, the specific particle is selectively driven by utilizing the characteristic that particles having a large particle diameter cannot follow. As a result, it is possible to control only particles having different colors and particle sizes, and it is possible to add a single color display or a plurality of color displays to a monocolor display.

By using the driving method of the present invention, it is possible to easily perform dynamic driving of electrophoretic display and selective driving of particles, which have been difficult until now, and improve display shading and contrast, and patterning of display panel electrodes and the like The display medium and the display device that can provide a single color display and partial color display at a low cost have been shown.

It is sectional drawing which shows the structure of a part of display panel of the display apparatus in one Embodiment of this invention. It is sectional drawing which shows the structure of a part of display panel of the display apparatus in one Embodiment of this invention. (A) It is sectional drawing for showing the name setting of an electrode at the time of calculating | requiring the characteristic with respect to the voltage of the display apparatus in one Embodiment of this invention, and an observation surface. (B) It is an example of the characteristic curve which showed the characteristic with respect to the voltage of the display apparatus in one Embodiment of this invention. (C) It is an example of the characteristic curve which showed the dielectrophoretic characteristic of the display apparatus in one Embodiment of this invention. (D) It is an example of the characteristic curve which showed the characteristic with respect to the frequency and particle diameter of the alternating voltage of the display apparatus in one Embodiment of this invention. (I) It is the front view which looked at the display panel (3x3 matrix) of the display apparatus in one Embodiment of this invention from the COMMON side electrode surface, and shows the preparatory stage of display operation | movement. (I) ′ shows voltage waveforms applied to the respective electrodes in the preparation stage of the display panel of the display device according to the embodiment of the present invention. (II) It is the front view which looked at the display panel (3x3 matrix) of the display apparatus in one Embodiment of this invention from the COMMON side electrode surface. (II) 'shows an example of a voltage waveform applied to each electrode during drawing of the display panel of the display device according to the embodiment of the present invention. (III) It is the front view which looked at the display panel (3x3 matrix) of the display apparatus in one Embodiment of this invention from the COMMON side electrode surface. (III) ′ An example of a voltage waveform applied to each electrode during drawing of the display panel of the display device according to the embodiment of the present invention is shown. (A) Schematic diagram inside a microcapsule at the time of drawing (white display) of the display panel of the display device in one embodiment of the present invention (A) 'At the time of drawing of the display panel of the display device in one embodiment of the present invention An example of the voltage waveform applied to each electrode of (white display) is shown. (B) Schematic diagram inside the microcapsule at the time of drawing (color display) of the display panel of the display device in one embodiment of the present invention (b) 'At the time of drawing of the display panel of the display device in one embodiment of the present invention An example of the voltage waveform applied to each electrode of (color display) is shown.

  The display device of the present invention is characterized in that electronic ink in which a dispersion system containing migrating particles is included in a microcapsule is provided between opposing transparent electrodes, and conditions for applying alternating current and direct current to each electrode of the display device To conduct dielectrophoresis of particles.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  In the present embodiment, a transparent base material provided with transparent electrodes arranged in a stripe shape is illustrated as a method for manufacturing a display device having matrix-like pixels in which electrode surfaces are superposed with each other at right angles, respectively. After describing an example of the voltage waveform applied to the electrode and optical characteristics viewed from one electrode, the present invention will be described by illustrating a driving method.

  First, a display device according to the present invention will be described.

  1 and 2 are cross-sectional views showing the structure of a part of the display panel of the display device.

  FIG. 1 shows a cross-sectional view of the display panel 11.

  As the transparent substrates 11a and 11e, a transparent glass substrate or a transparent plastic resin substrate can be used. When obtaining a flexible display panel, it has excellent dimensional stability such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide, etc., with a thickness of 50 to 500 μm. The plastic resin substrate used is used.

  In order to improve barrier resistance, if necessary, polyvinyl alcohol copolymer, polyvinyl alcohol, SiOx, SiNx are provided by coating or vapor deposition, or impregnation with a known UV absorber or coating treatment is performed to improve light resistance. Also good.

  The transparent conductive layers 11b and 11d are formed by forming a transparent conductive material (thickness) such as indium tin oxide (ITO), tin oxide (NESA), or zinc oxide by a known method such as sputtering, vacuum deposition, or CVD. 100 to 2500 mm) and formed by patterning by etching.

  A configuration when the microcapsule electrophoresis method is used for the image display layer 11c will be described.

  Next, an example of the microcapsule 110 is shown in FIG.

  The microcapsule 110 has a capsule shell 111 made of methacrylic acid resin, urea resin, gum arabic or the like, and white particles 113 (or particles 115) made of titanium oxide inside, black particles 114 made of carbon black, and pigments or colored particles. 116 is dispersed using a highly viscous transparent dispersion medium 112 such as aliphatic hydrocarbon, aromatic hydrocarbon, alicyclic hydrocarbon, halogenated hydrocarbon, various esters, alcohol solvents, silicone oil, and the like. , And encapsulated in a microcapsule produced using a known method such as a phase separation method such as a complex coacervation method, an interfacial polymerization method, an in-situ method, or a solution dispersion cooling.

  The white particles 113 (or particles 115) made of titanium oxide and the black particles 114 made of carbon black and the pigment or colored particles 116 encapsulated in the microcapsule have a diameter of 0.1 μm to 20 μm, considering migration within the microcapsule. Preferably, a material having a thickness of 1 μm to 10 μm can be used, and a surface coating with a polymer resin can be applied to prevent aggregation and to induce polarization during migration.

  The microcapsules are preferably screened as necessary, and the capsule diameter distribution is preferably adjusted to 1 to 300 μm by an arbitrary method such as a specific gravity separation method, taking into account the density in the subsequent process and display such as coating, Preferably, it is preferably adjusted to 5 to 200 μm.

  The microcapsules thus produced are dispersed together with binder resins such as vinyl chloride / vinyl acetate copolymer system, urethane system, epoxy system, acrylic system, polyester system, roll coater, knife coater, die coater, reverse roll coater, The image display layer 11c having a thickness of 5 μm to 100 μm can be provided by using an existing printing method such as a blade coater, a rod coater, a comma coater, a gravure coater, an applicator, a bar coater, a spin coater, or a screen printing method, or a coating method. .

  In display by normal electrophoresis, titanium oxide, which is white particles in the microcapsule, has a positive electrode, while carbon black, which is black particles, has a negative charge. ), When a voltage is applied to a pair of electrodes (here, COMMON and SEGMENT are specified) as a negative electrode on the COMMON side and a positive electrode on the SEGMENT side, positively charged white particles 113 are attracted to the COMMON side, When the black particles 114 are drawn to the SEGMENT side and observed from the COMMON side, the portion to which the voltage is applied appears white.

  Conversely, when a voltage is applied with the COMMON side as the positive electrode and the SEGMENT side as the negative electrode, the positively charged white particles 113 are attracted to the SEGMENT side, while the black particles 114 are attracted to the COMMON side and observed from the COMMON side. The part where is applied appears black.

  FIG. 3B shows the reflection density of the pixel when the COMMON side electrode is kept at 0.0 V and the voltage of the SEGMENT electrode is set to 0.5 V, 1.0 V, 8.0 V, and 10.0 V, respectively. It is the characteristic curve which showed the relationship with reaction time.

  In this measurement, the pixel was set to white (Optical Density = about 0.59) in advance before applying the voltage.

  This characteristic curve shows that it is necessary to apply a relatively high voltage (10 V) in order to move the migrating particles quickly.

  However, when a voltage of 8 V is applied, the response time is delayed, but a color change is observed, but it does not show a clear threshold such as a sudden response from a certain voltage like liquid crystal.

  Although there is a voltage region where no response is seen even after a certain period of time, it is a considerably low voltage region compared to a voltage that can be driven sufficiently, so dynamic drive such as a simple matrix has been performed so far It was not suitable for. (Particles move and the contrast deteriorates.)

Therefore, in the driving method of the present invention, by using the dielectrophoresis phenomenon of particles, the simple matrix driving and the selective particle control are realized at the same time.

Dielectrophoresis is a phenomenon in which a substance (particle) placed in an inhomogeneous electric field moves by the interaction of the surrounding electric field and the dipole moment induced thereby.

In electrophoresis, it moves toward the electrode along a line of electric force due to a simple applied voltage, whereas in dielectrophoresis, it moves according to the gradient of the electric field strength.

Further, depending on the polarizability of a substance (particle), the migration speed varies depending on the expression of positive and negative dielectrophoresis (related to the migration direction) and the difference in dielectric constant.

In the present invention, as a property of the dielectrophoresis, the property that the migration cannot follow the high-frequency AC pulse voltage when the particle size is actually confirmed and utilized.

That is, the operation of particles in a selected area on the electrode is controlled by the applied voltage (AC pulse voltage), the offset voltage, and the frequency and number of pulses of the AC pulse voltage.

This will be described in detail below with reference to figures and graphs.

FIG. 3C shows pixel reflection when an AC voltage of 10 Hz and ± 10 V is applied to the COMMON side electrode, and each voltage of 0.0 V, −0.5 V, and −1.0 V is applied to the SEGMENT side electrode. It is the characteristic curve which showed the relationship between a density | concentration and reaction time.

By applying a pulsed AC voltage from the COMMON side electrode, particle polarization is induced, and by applying a negative voltage to the SEGMENT side electrode, an offset is applied to the AC waveform applied from the COMMON side electrode. Uniform alternating current is used, and the direction of dielectrophoresis movement is controlled.

  Compared with FIG. 3 (b), it is shown that not only the SEGMENT side voltage but also the migration of the migrating particles is facilitated by the application of the AC voltage.

  It is possible to obtain a clearer change in response that has not been seen in the past due to the presence or absence of an AC electric field, and it can be applied to dynamic driving such as a simple matrix, as well as particle movement depending on the number of AC pulses (application time). It became possible to control the distance.

  Specifically, an AC voltage waveform is applied to the electrode corresponding to the COMMON side electrode related to the pixel to which the electrophoretic particles are to be moved, and a positive or negative voltage is applied to the electrode corresponding to the SEGMENT side electrode of the pixel for offsetting. Thus, it is possible to drive the electrophoretic particles of the pixel at the portion intersecting with the electrodes.

On the other hand, a pixel related to an electrode corresponding to the COMMON side electrode not applied with an AC voltage waveform is not driven unless a voltage of a certain level or higher is applied to the electrode corresponding to the SEGMENT side electrode.

  It is possible to perform display using the contrast of these pixels.

  Note that the electrodes corresponding to the SEGMENT side may be sequentially applied with voltages to a part of the arranged electrodes, or may be applied simultaneously, and if they are applied simultaneously, the time required for rewriting the image display Can be drastically shortened.

  The AC pulse voltage on the COMMON side can operate in the range of 4.0 Vp-p to 40.0 Vp-p, but is preferably 10.0 Vp-p to 20.0 Vp-p. Moreover, although the operation | movement with a frequency of 5 Hz-30 Hz is possible, Preferably it shall be 8 Hz-15 Hz. The conditions of these voltage waveforms vary depending on the particles used, the filling rate, the solvent viscosity, and the size of the microcapsules, and it is preferable to set the conditions according to the characteristics.

  FIG.3 (d) is an experimental result which shows the difference in behavior by particle diameter at the time of applying the alternating voltage pulse voltage of a certain frequency.

  In this case, when the particle size is small (2 μm), the behavior of dielectrophoresis can be confirmed even under a high frequency condition, whereas when the particle size is relatively large (8 μm), migration is hardly observed.

  In the case of a large particle size, the polarization is induced by the non-uniform (offset) AC pulse voltage, but it is considered that the migration does not follow due to the weight of the particle and the resistance of the nearby filling liquid.

  That is, when particles having different frequency characteristics are simultaneously used for dielectrophoresis, it is possible to induce migration by selecting the particle size.

  Thereby, for example, colored particles having different particle diameters can be mixed in the microcapsules, or microcapsules containing particles of different colors can be arranged at the same time, whereby color display can be performed.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise indicated, “parts” are parts by weight.

  First, a dispersion liquid in which each of titanium oxide having a particle size of 2 μm surface-treated with polyethylene resin and red particles having a particle size of 1 to 2 μm (Pigment Red122) surface-treated with stearylamine acetate was dispersed in tetrachloroethylene was prepared.

  About 40 parts of the dispersion liquid was mixed with an aqueous solution in which 10 parts of gelatin and 0.1 part of polystyrene sulfonate were mixed in 80 parts of water, the liquid temperature was adjusted to 40 ° C., and the homogenizer was used while maintaining the liquid temperature. Stirring to obtain an O / W emulsion.

  Next, the obtained O / W emulsion is mixed with an aqueous solution in which 10 parts of gum arabic is blended with 80 parts of water adjusted to 40 ° C., and the solution temperature is kept at 40 ° C. using acetic acid. The pH was adjusted to 4, and microcapsule walls were formed by coacervation.

  Further, after the liquid temperature was lowered to 5 ° C., 1.9 parts of a 37 wt% formalin solution was added to harden the microcapsule wall, thereby producing microcapsules enclosing white particles and red particles.

  These microcapsules were sieved to obtain microcapsules having a diameter of 40 μm.

  Also, using a dispersion in which 8 μm particle diameter titanium oxide surface-treated with a polyethylene resin and 8 μm particle size carbon black particles surface-treated with alkyltrimethylammonium chloride were dispersed in tetrachloroethylene, the diameter was reduced to 40 μm as described above. Prepared microcapsules.

  To 100 parts of the toluene solution and 80 parts of the polyurethane-based resin, 80 parts of the total microcapsules 1: 1 prepared above were mixed to obtain an image display layer ink.

  Two transparent glass substrates on which indium tin oxide (ITO) electrodes are formed in three rows of stripes are prepared, and the image display layer ink is coated on the electrode surface of one of the glass substrates using an applicator. For 30 minutes to obtain an image display layer having a film thickness of 60 μm.

  An electrophoretic display panel provided with pixels in a matrix was obtained by superposing the electrode surfaces so that one glass substrate faced 90 ° C.

  FIG. 4 shows a front view of electrophoretic display panels (I) to (III) in which pixels are arranged in a 3 × 3 matrix, and voltage waveforms (I) ′ to (III) ′ applied at the time of driving. The front view of the display panel is viewed from the COMMON electrode side.

  Each pixel is described as drawing by shifting from a white state to a black state, but it is also possible to change all pixels to black and then partially change to white.

  (I) and (I) ′ show a state indicating an initial stage of drawing and a voltage waveform applied at that time. First, the operation of collecting the white particles 113 (and 115) on the COMMON electrode side is a process for improving the display quality, and there is a case where it is not particularly necessary.

  By applying an AC waveform to the COMMON side electrodes COM0 to COM2, and applying a slight positive voltage to the SEGMENT side electrodes SEG0 to SEG2, the applied voltage in the pixel is changed to a non-uniform AC voltage whose negative side is increased. Make it white.

  Next, as shown in (II) and (II) ′, an alternating waveform is applied to COM0, a positive voltage is applied to SEG0 and SEG2, and a negative voltage is applied to SEG1, so that COM0 and SEG0 and SEG2 cross each other. The pixel of is in the white state as in the cases of (I) and (I) ′.

  On the other hand, in the pixel where COM0 and SEG1 intersect, contrary to the cases of (I) and (I) ′, the AC pulse voltage in the pixel becomes a non-uniform AC voltage that is increased to the positive side. Show.

  Furthermore, since only a DC voltage of ± 0.5 V is applied to the pixels where COM1 and COM2 and SEG0-2 intersect, no movement of particles is observed as shown in FIG.

  Similarly, in (III) and (III) ′, an alternating waveform is applied to COM1, a negative voltage is applied to SEG0, and a positive voltage is applied to SEG1, so that the pixels where COM1 and SEG0 intersect are black, and COM1 and SEG1 intersect. Pixels that do this are white.

  On the other hand, by giving SEG2 a waveform (about half the pulse) in which the negative voltage is applied for a shorter time than SEG0, the pixel where COM1 and SEG2 intersect is darker than the pixel where COM1 and SEG0 intersect. Is in a low state (particle movement is small).

Next, a voltage similar to that shown in FIG. 5 (a) 'is applied to the electrode once again, and each electrode is brought into a state indicating the initial stage of drawing. Then, a voltage similar to that shown in FIG. Only the capsule was driven and the red particles moved to the front of the screen.

  The present invention relates to a driving method of an image display device that performs display by inducing and controlling dielectrophoresis of particles encapsulated in a microcapsule. Can be used for realization.

11 ... Display panel 11a ... Transparent substrate 11b ... Transparent conductive layer 11c ... Image display layer 11d ... Transparent conductive layer 11e ... Transparent substrate 110 ... Microcapsule 111 ... · Capsule shell 112 ... Dispersion medium 113 ... White particles 114 ... Black particles 115 ... White particles (small particle size)
116... Pigment or colored particles (small particle size)

Claims (4)

A method for driving an image display device, wherein a microcapsule in which white, black, or colored particles are encapsulated with a dispersion medium is disposed with a binder between at least one of the transparent electrodes,
An alternating current pulse voltage is applied to one electrode of an image display device in which microcapsules containing particles having different colors and particle sizes or a plurality of types of microcapsules containing particles having different colors and particle sizes are mixed. A driving method of an image display device, wherein a DC voltage is applied to one electrode to control particles in a microcapsule.   2. The driving method according to claim 1, wherein the induction of particles is induced by an AC pulse voltage applied to one electrode and an offset is applied to the AC pulse voltage waveform by a DC voltage applied to the other electrode. A driving method of an image display device, characterized by controlling a moving direction. 3. The driving method according to claim 1, wherein the moving distance of the particles is controlled by adjusting the number of pulses of the non-uniform AC pulse voltage to which the offset is applied, and the display density is adjusted. Method.   4. The driving method according to claim 1, wherein at least a frequency of an alternating pulse voltage at which all of the plurality of particle types included in the microcapsule migrate and one of the plurality of particle types included in the microcapsule is selected. A method for driving an image display device, characterized in that display is performed by combining frequencies of alternating pulse voltages at which only types migrate.