JP2006243154A - Particle movement type display element and particle movement type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a particle movement type display element and a particle movement type display device capable of stable halftone display for a long term.
A magnetic member that restricts movement of colored charged magnetic particles 2 to the other substrate side of the first substrate 3 and the second substrate 4 by a magnetic force on one substrate side of the first substrate 3 and the second substrate 4. 10 and the magnetic member 10 is configured so as to generate different magnetic fields stepwise along the electrode on one substrate side, thereby collecting the first electrode 5 and the second electrode on the one substrate side. Of the colored charged magnetic particles 2 that have received an electrostatic force due to an electric field generated between the electrodes 6, the colored charged magnetic particles 2 that have received an electrostatic force greater than the magnetic force acting between the colored charged magnetic particles 2 and the magnetic member 10 are used as the other. Move to the substrate side.
[Selection] Figure 1

Description

  The present invention relates to a particle movement type display element and a particle movement type display device that perform display by moving colored charged magnetic particles, and more particularly, to a device equipped with a magnetic member that regulates the movement of colored charged magnetic particles.

  In recent years, with the development of information equipment, the need for low power consumption and thin display devices is increasing, and research and development of display devices that meet these needs are actively conducted. In particular, reflective display devices are expected from the viewpoints of low power consumption and reduction of visual burden.

  Here, as an example of such a reflection type display device, there is a particle movement type display device that performs display by moving colored charged magnetic particles, and such a particle movement type display device includes a charge in an insulating liquid. There is an electrophoretic display device that performs display by moving electrophoretic particles. Furthermore, as such an electrophoretic display device, for example, an apparatus including an electrophoretic display element including a magnetic member that regulates the movement of colored charged magnetic particles has been devised (for example, see Patent Document 1).

  By the way, as shown in FIG. 7, an electrophoretic display element using such a conventional magnetic member has a charged colored charged magnetic particle 62 containing a magnetic material and a colored dye having a color different from that of the colored charged magnetic particle 62. A dispersion layer made of an insulating liquid 61 in which is dissolved, a microcapsule 67 containing the dispersion layer, a pair of electrodes 65 and 66 facing each other with the microcapsule 67 interposed therebetween, and a pair of substrates 63 and 64 And a magnetic member 68 formed in one of the substrates.

  When display is performed in such an electrophoretic display element, a voltage is applied to the dispersion layer via the electrodes 65 and 66, and the colored charged magnetic particles 62 are attracted to an electrode having a polarity opposite to the charge of the particles themselves. Like that. The display is performed by the color of the colored charged magnetic particles 62 and the color of the insulating liquid 61 in which a coloring pigment different from the hue of the colored charged magnetic particles 62 is dissolved.

  For example, in the state where the colored charged magnetic particles 62 are collected on the first electrode 65 side as shown in FIG. 7B, the first electrode 65 is used as the positive electrode and the second electrode 66 is used as the negative electrode. When the electrostatic force generated by the electric field between 65 and the second electrode 66 is greater than the magnetic force acting between the magnetic member 68 and the colored charged magnetic particles 62, the positive force is obtained as shown in FIG. The charged colored magnetic particles 62 with charges move to the second electrode 66 side. At this time, the color of the colored charged magnetic particles 62 is displayed from the observer (second substrate 64 side).

  On the other hand, as shown in FIG. 7A, when the colored charged magnetic particles 62 are gathered on the second electrode side and the first electrode 65 is the negative electrode and the second electrode 66 is the positive electrode, As shown in (b), the positively charged colored charged magnetic particles 62 move to the first electrode 65 side. At this time, the color of the coloring pigment contained in the insulating liquid 61 is displayed from the observer (second substrate 64 side).

  When the electrostatic force generated by the electric field between the first electrode 65 and the second electrode 66 is smaller than the magnetic force acting between the magnetic member 68 and the colored charged magnetic particles 62, the colored charged magnetic particles 62 are Maintain the position before applying voltage. That is, the colored charged magnetic particles 62 have a threshold value corresponding to the magnetic force acting between the magnetic member 68 and the colored charged magnetic particles 62, and an electrostatic force exceeding the threshold value is applied. In addition, the colored charged magnetic particles 62 can move.

WO02 / 093245 A1 publication

  By the way, in such a conventional electrophoretic display element, the threshold voltages corresponding to the threshold values of all the colored charged magnetic particles 62 are the same. For this reason, when halftone display is performed, by applying a voltage lower than the voltage at which the colored charged magnetic particles 62 can completely move between the pair of electrodes and higher than the threshold voltage, The key was displayed.

  In this case, however, the colored charged magnetic particles 62 are dispersed in the insulating liquid 61 without adhering to the surface of the microcapsule 67 as shown in FIG. Here, in the state where the colored charged magnetic particles 62 are dispersed in the insulating liquid 61 as described above, in order to fix the position of the colored charged magnetic particles 62 and maintain a halftone display state over a long period of time, The specific gravity of the colored charged magnetic particles 62 and the insulating liquid 61 must be matched.

  For this purpose, it is necessary to lower the specific gravity of the colored charged magnetic particles 62 or increase the specific gravity of the insulating liquid 61. In particular, when the colored charged magnetic particles 62 containing a magnetic member are used, the insulating liquid is used. Since the weight of the colored charged magnetic particles 62 is heavier than that of the 61, there is a problem that the selection range of the material becomes very narrow in order to make the specific gravity of the insulating liquid 61 and the colored charged magnetic particles 62 coincide.

  Therefore, the present invention has been made to solve such problems, and an electrophoretic display element (particle movement type display element) and an electrophoretic display device that enable stable halftone display over a long period of time. The object is to provide a (particle movement type display device).

  According to the present invention, colored charged magnetic particles are arranged between a first substrate and a second substrate arranged with a gap, and the colored charged magnetic particles are arranged so as to face the gap and the first electrode and In a particle movement type display element that displays an image by moving in a gap by an electric field generated between two electrodes, the first substrate of the colored charged magnetic particles is disposed on one of the first substrate and the second substrate. The movement of the second substrate to the other substrate side is restricted by magnetic force, and different magnetic fields are generated stepwise along the electrode on the one substrate side of the first electrode and the second electrode. Among the colored charged magnetic particles that are provided with a configured magnetic member and are collected on the one substrate side and have received an electrostatic force due to an electric field generated between the first electrode and the second electrode, the colored charged magnetic particles and the Greater than the magnetic force acting between magnetic members It is characterized in that to move the colored charged magnetic particles that have undergone electric force on the substrate side of the other.

  As in the present invention, on one substrate side of the first substrate and the second substrate, a magnetic member for restricting the movement of the colored charged magnetic particles to the other substrate side of the first substrate and the second substrate by a magnetic force is provided, In addition, by configuring the magnetic member to generate different magnetic fields stepwise along the electrode on one substrate side, the electric field collected between the first substrate side and generated between the first electrode and the second electrode is generated. Among the colored charged magnetic particles subjected to the electrostatic force by the colored charged magnetic particles, the colored charged magnetic particles that have received an electrostatic force larger than the magnetic force acting between the colored charged magnetic particles and the magnetic member can be moved to the other substrate side. As a result, the colored charged magnetic particles are not dispersed in the insulating liquid, and a stable halftone display is possible over the long term.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an electrophoretic display element which is an example of the particle movement type display element according to the first embodiment of the present invention. As shown in FIG. A second substrate 4 on the display side and a first substrate 3 on the rear side, which are a pair of substrates arranged with a predetermined gap therebetween, and a partition wall 9 for forming a gap between these substrates 3 and 4; An insulating liquid 1 disposed in a space surrounded by the substrates 3 and 4 and the partition walls 9 and a plurality of colored charged magnetic particles 2 dispersed in the insulating liquid 1 are provided.

  This electrophoretic display element has pixels arranged in a matrix on a substrate, and the partition wall 9 also has a function of preventing the colored charged magnetic particles 2 from moving between adjacent pixels.

  The first electrode 5 is disposed on the surface of the first substrate 3 facing the second substrate 4, and the first electrode 5 defines one unit of display, that is, a pixel. The surface of the first electrode 5 is covered with the first insulating layer 7.

  On the other hand, the second electrode 6 to which a voltage having a polarity different from that of the first electrode 5 is applied is disposed on the second substrate 4. Then, by forming an electric field for controlling the spatial distribution of the colored charged magnetic particles 2 containing the magnetic material between the first electrode 5 and the second electrode 6 arranged facing the space (gap). The colored charged magnetic particles 2 are moved between the first electrode 5 and the second electrode 6. The surface of the second electrode 6 is covered with an insulating layer 8.

  Further, in the vicinity of the dispersion layer composed of the insulating liquid 1 and the colored charged magnetic particles 2, magnetic forces that differ stepwise in the electrode in-plane direction, which is the direction along the first electrode 5, with respect to the colored charged magnetic particles 2. A plurality of magnetic members 10 to be added are juxtaposed in the in-plane direction of the electrode. Here, the magnetic member 10 can be disposed on the first substrate 3, the first electrode 5, the first insulating layer 7, or the inside thereof. The magnetic member 10 is disposed on the second substrate 4, the second electrode 6, the second insulating layer 8, or the inside of the second substrate 4, if the insulating liquid 1 and the colored charged magnetic particles 2 can be observed by an observer. can do.

  By the way, in the electrophoretic display element having such a configuration, the colored charged magnetic particles 2 in the insulating liquid 1 are applied with a voltage between the first electrode 5 and the second electrode 6 to apply the first electrode 5 and the second electrode 6. The display is performed by moving between the electrodes 6. For example, as the insulating liquid 1, by using the insulating liquid 1 in which a coloring pigment different from the colored charged magnetic particles 2 is dissolved, monochrome display or the like can be performed. Two-color display can be realized.

  Further, by changing the size (length) of the magnetic member 10 in the electrode surface direction in stages, different magnetic forces can be applied to the colored charged magnetic particles 2 in steps in the electrode surface direction. . Then, by applying different magnetic forces stepwise to the colored charged magnetic particles 2 in this way, a voltage is applied between the electrodes, and the maximum of the magnetic force applied stepwise to the colored charged magnetic particles 2. When an electrostatic force smaller than the value is applied, only the colored charged magnetic particles 2 to which a magnetic force smaller than the electrostatic force is applied migrate between the electrodes, and as a result, halftone display becomes possible.

  In other words, in the present embodiment, by changing the size of the magnetic member 10 in the electrode in-plane direction, different magnetic forces are applied to the colored charged magnetic particles 2 in the electrode in-plane direction. At the same time, by applying a voltage that can apply an electrostatic force smaller than the maximum value of the magnetic force applied by the magnetic member 10 between the electrodes, the colored charged magnetism to which a magnetic force smaller than the electrostatic force is applied is applied. Only particle 2 can be migrated.

  Next, a display method of the electrophoretic display element having such a configuration will be described. In the following description, it is assumed that the colored charged magnetic particles 2 in the insulating liquid 1 colored in a different color from the colored charged magnetic particles 2 are positively charged.

  Here, when the second electrode 6 is used as a positive electrode and the first electrode 5 is used as a negative electrode and an electrostatic force is applied to the colored charged magnetic particles 2, as shown in FIG. 2A, positively charged colored charged magnetic particles 2. Are collected on the first electrode 5, and the colored charged magnetic particles 2 adhere to the first insulating layer 7. At this time, the color of the insulating liquid 1 colored in a different color from the colored charged magnetic particles 2 is observed from the observer (second substrate 4 side).

  On the other hand, with the colored charged magnetic particles 2 attached on the first insulating layer 7 as shown in FIG. 2A, the polarity of the voltage applied to the first electrode 5 and the second electrode 6 is changed, When an electrostatic force larger than the maximum value of the magnetic force acting between the colored charged magnetic particles 2 and the magnetic member 10 on the first insulating layer 7 is applied to the colored charged magnetic particles 2, FIG. As shown, the colored charged magnetic particles 2 move to the second electrode 6 side, and the second insulating layer 8 is covered with the colored charged magnetic particles 2. At this time, the color of the colored charged magnetic particles 2 is observed from the observer (second substrate 4 side).

  Here, for example, if the color of the colored charged magnetic particles 2 is white and the color of the insulating liquid 1 is black, monochrome display is possible. Color display is also possible by newly providing a color filter on the insulating liquid 1 colored in a plurality of hues (for example, yellow, cyan, magenta, etc.), the colored charged magnetic particles 2, or the substrates 3 and 4. It becomes.

  By the way, when displaying a halftone, for example, as shown in FIG. 2A, the first electrode 5 is used as the positive electrode, with the colored charged magnetic particles 2 attached on the first insulating layer 7, and the first electrode 5 as the positive electrode. The two electrodes 6 are made negative, and the voltage applied to the first electrode 5 and the second electrode 6 is made to exert an electrostatic force smaller than the maximum value of the magnetic force applied stepwise to the colored charged magnetic particles 2. It is made to be a big size.

  When a voltage having such a magnitude is applied to the first electrode 5 and the second electrode 6, both sides of the magnetic member 10 to which a magnetic force smaller than the electrostatic force is applied have a small magnitude in the electrode plane direction. Only the colored charged magnetic particles 2 facing the portion migrate between the electrodes and move to the second electrode 6 side. In addition, the colored charged magnetic particles 2 facing the central portion of the magnetic member 10 to which a magnetic force larger than the electrostatic force is applied and having a large size in the electrode in-plane direction do not migrate.

  As a result, as shown in FIG. 2C, all the colored charged magnetic particles 2 adhere to the first insulating layer 7 or the second insulating layer 8. And by attaching all the colored charged magnetic particles 2 to the first insulating layer 7 or the second insulating layer 8 in this way, the colored charged magnetic particles 2 dispersed in the insulating liquid 1 can be eliminated, As a result, clear and long-term stable halftone display is possible.

  In the present embodiment, the magnetic member 10 is patterned so as to generate a closed magnetic field around the magnetic member 10, and by generating a closed magnetic field around the magnetic member 10 in this way, The magnetic force acting between the magnetic member 10 and the colored charged magnetic particles 2 in the normal direction can be sharply attenuated. As a result, the colored charged magnetic particles 2 that have once moved away from the first insulating layer 7 are accelerated by the attenuation of the magnetic force and move to the second insulating layer 8 side.

  Further, by steeply decreasing the magnetic force in this way, the colored charged magnetic particles 2 during migration can be prevented from being affected by the magnetic force in the in-plane direction of the electrode. , It is possible to prevent uneven distribution in a portion having the strongest magnetic force in the pixel.

  On the other hand, the magnitude of the force acting between the colored charged magnetic particles 2 and the magnetic member 10 is determined by the gradient of the magnetic field generated by the magnetic member 10 and the magnitude of the magnetization of the colored charged magnetic particles 2. The acceleration effect of the particles 2 is increased by adopting a configuration in which the colored charged magnetic particles 2 have a magnetization almost zero when no external magnetic field is applied. Further, by giving the colored charged magnetic particles 2 a characteristic that the magnetization is substantially zero when no external magnetic field is applied, the colored charged magnetic particles 2 are prevented from aggregating during migration due to the colored charged magnetic particles 2 having magnetization. be able to.

  That is, by giving the colored charged magnetic particles 2 the characteristic that the magnetization is substantially zero when no external magnetic field is applied, the colored charged magnetic particles 2 during electrophoresis are aggregated by the magnetic force generated by their own magnetization. You can avoid that. Further, the magnetization decreases due to the reduction of the magnetic field during electrophoresis, thereby increasing the difference in magnetic force between the case where the magnet is attached to the first insulating layer 7 or the second insulating layer 8 and the case where the electrophoresis is performed. As a result, an increase in driving voltage can be suppressed and an electrophoresis speed can be increased.

  Next, a method for manufacturing the electrophoretic display element having such a configuration will be described. In the following description, attention is paid to only one pixel among pixels arranged in a matrix, and the manufacturing process will be described with reference to FIG.

  First, as shown in FIG. 3A, a conductive film is formed on the first substrate 3 to form the first electrode 5. As the first substrate 3, an inorganic material such as glass or quartz, or a polymer material such as polyethylene terephthalate (PET), polyethersulfone (PES), or polycarbonate can be used.

  Next, as shown in FIG. 3B, the magnetic member 10 is formed on the first electrode 5, and the magnetic member can be generated in a stepwise manner in the in-plane direction of the electrode. Patterning is performed so that the length in the in-plane direction of the electrode 10 changes stepwise. As the material of the magnetic member 10, for example, a rare earth-transition metal amorphous alloy, a noble metal-transition metal alloy, or various magnet materials are formed.

  Next, as shown in FIG. 3C, the first insulating layer 7 is formed on the magnetic member 10. In addition, as a material of the 1st insulating layer 7, what is hard to form a pinhole in a thin film is good, For example, a polyimide, PET, polymethylmethacrylate (PMMA) etc. can be used.

  Next, a partition wall 9 is formed on the first insulating layer 7. In addition, as a material of the partition wall 9, a polymer resin or the like is used. In addition, any method may be used for forming the partition wall 9. For example, a method of performing exposure and wet development after applying a photosensitive resin layer, or a method of bonding a separately manufactured partition wall, or the like is used. Can do.

  Next, the 2nd board | substrate provided with the 2nd electrode 6 and the 2nd insulating layer 8 shown to (d) of FIG. 3 is manufactured separately. Here, the second electrode 6 is formed by forming a conductive film on the second substrate 4, and the second insulating layer 8 is formed on the second electrode 6.

  In addition, as the material of the second substrate 4, a material having high optical transparency, for example, an inorganic material such as glass or quartz, or a polymer material such as polyethylene terephthalate (PET), polyethersulfone (PES), or polycarbonate is used. can do. Moreover, as a material of the 2nd electrode 6, a material with high light transmittance, for example, ITO etc., can be used. Further, the material of the second insulating layer 8 is preferably a material having high light transmittance and difficult to form pinholes. For example, polyimide, PET, polymethyl methacrylate (PMMA), or the like can be used.

  Next, the partition wall 9 is filled with the insulating liquid 1 and the colored charged magnetic particles 2. Further, a charge control material or the like is added as necessary. The insulating liquid 1 is a colored liquid in which a dye is dispersed in an insulating liquid such as silicone oil. Further, as the charged charged magnetic particles 2, a material that can be charged in the insulating liquid 1, for example, a resin such as polyethylene or polystyrene in which a magnetic member such as magnetite or maghemite is encapsulated is used. Furthermore, particles containing a pigment or dye together with a magnetic member are used as necessary.

  Next, after forming an adhesive layer on the joint surface between the second insulating layer 8 and the partition wall 9, the first substrate 3 and the second substrate 4 are aligned, and the second insulating layer 8 and the partition wall 9 are brought into contact with each other. Bonding by heat or UV irradiation.

  An electrophoretic display device having an electrophoretic display element as shown in FIG. 3D is obtained by providing a voltage applying means (not shown). The electrophoretic display device manufactured by the above method can perform binary display, color display, and clear halftone display.

  In this way, the size of the magnetic member 10 in the in-plane direction of the magnetic member 10 is changed stepwise so as to generate different magnetic fields along the second electrode 6. Among the colored charged magnetic particles subjected to the electrostatic force due to the electric field generated between 5 and 6, the colored charged magnetic particles 10 receiving the electrostatic force larger than the magnetic force acting between the colored charged magnetic particle 2 and the magnetic member 10 are secondly used. It can be moved to the substrate side. As a result, the colored charged magnetic particles 2 are not dispersed in the insulating liquid, and a stable halftone display is possible over a long period of time.

  In the above description, in order to generate different magnetic fields stepwise in the electrode surface direction, the size (length) of the parallel magnetic members 10 in the electrode surface direction is changed stepwise. However, in addition to this, for example, the size (length) in the normal direction of the electrode surface of the magnetic members 10 formed continuously or arranged side by side as shown in FIG. Alternatively, the interval may be changed stepwise in the electrode in-plane direction without changing the length of the magnetic members 10 arranged in parallel as shown in FIG. Further, as the magnetic member 10, a plurality of types of magnetic members 10 having different magnetic characteristics may be disposed in the electrode surface.

  Next, a second embodiment of the present invention will be described.

  FIG. 6 is a diagram showing a schematic configuration of the electrophoretic display element according to the present embodiment. As shown in FIG. 6, the electrophoretic display element has a second electrode 56 provided inside a partition wall 58. In addition, a transparent liquid is used as the insulating liquid 51, and the colored charged magnetic particles 52 are applied with a voltage between the first electrode 55 installed on the bottom surface of the pixel and the second electrode 56 installed inside the partition wall 58. The display is moved by application to display. The display is performed by the color of the colored charged magnetic particles 52 and the color of the insulating layer 57, the first electrode 55, or the first substrate 53 colored in a different color from the colored charged magnetic particles 52.

  Further, the magnetic member 59 is disposed on the first electrode surface. By arranging the magnetic member 59 in this way, the colored charged magnetic particles 52 correspond to the magnetic force acting between the magnetic member 59 and the magnetic member 59. Will have a threshold.

  Here, in such a configuration, since the electric field is different at different locations in the in-plane direction of the first electrode 55, the driving voltage of the colored charged magnetic particles 52 at different locations in the in-plane direction of the first electrode 55 is Different.

  In consideration of this electric field distribution, the magnetic force acting between the magnetic member 59 and the colored charged magnetic particles 52 is changed stepwise in the in-plane direction of the first electrode 55, thereby causing the in-plane direction of the first electrode 55. A necessary threshold value can be appropriately given to the colored charged magnetic particles 52 in different places, and the colored charged magnetic particles 52 that have received an electrostatic force exceeding the threshold value can be migrated to the partition wall 58 side. As a result, the colored charged magnetic particles 2 are not dispersed in the insulating liquid, and a stable halftone display is possible over a long period of time.

  Next, examples of the present invention will be described.

  First, in this embodiment, as an electrophoretic display device having pixels arranged in a matrix on a substrate, a device in which single pixels are arranged in a matrix of 1000 rows and 1000 columns on a first substrate having a planar size of 150 mm × 150 mm. Is made. In the following description, a manufacturing process of one pixel having a planar dimension of 100 μm × 100 μm among pixels arranged in a matrix will be described.

  First, an Al film is formed as a conductive film on a glass substrate, which is the first substrate 3, and patterned to form the first electrode 5 (see FIG. 3A). Next, a TbFeCo film having a film thickness of 200 nm is formed as a magnetic member 10 on the surface, and the diameter of the colored charged magnetic particles 2 is increased to 0.1 to 1 times in the in-plane direction of the electrode using a lift-off method. Patterning is performed with different sizes in stages (see FIG. 3B).

  Next, an acrylic resin material (Opter made by JSR) is applied as a first insulating layer 7 on the magnetic member 10 by a spin coating method, and then the partition walls 9 are formed. The partition wall 9 is spin-coated with a thick film processing resist (Tokyo Ohka Kogyo PMER N-CA2000PMT-1) made of a photosensitive epoxy resin, and then subjected to photolithography to form a partition wall 9 having a height of 20 μm and a width of 5 μm. (See FIG. 3C).

  Next, an external magnetic field is applied to magnetize TbFeCo in the normal direction of the electrode surface. Thereafter, an ITO film is formed on the glass substrate as the second substrate 4 to form the second electrode 6. Further, an acrylic resin (Opter made by JSR) is applied as a second insulating layer 8 to the surface by a spin coating method (see FIG. 3D).

  Next, after a UV curable adhesive layer is formed on the bonding surface between the second insulating layer 8 and the partition wall 9, the insulating liquid 1 and the colored charged magnetism are formed in a region surrounded by the partition wall 9 and the first insulating layer 7. Fill particles 2. Here, as the insulating liquid 1, an anthraquinone-based black dye dispersed in silicone oil is used, and as the colored charged magnetic particles 2, magnetite fine particles and titanium oxide white pigment powder are included. Polystyrene particles having a particle diameter of about 5 μm are used. The colored charged magnetic particles 2 used have a white color close to that of pure titanium oxide.

  Next, the bonding position of the second insulating layer 8 and the partition wall 9 is aligned, and the second insulating layer 8 and the partition wall 9 are bonded by UV irradiation (see FIG. 3E).

  Next, display is performed using the electrophoretic display device thus manufactured. In addition, since the white colored charged magnetic particles 2 used in this example were positively charged in the insulating liquid 1, they move to the negative electrode when a voltage is applied.

  Therefore, for example, when the second electrode 6 is set to 0 V and the first electrode 5 is set to the negative electrode (−5 V), the positively charged colored charged magnetic particles 2 leave the second insulating layer 8 and move to the first insulating layer 7 side. Then, they are dispersed and attached to the first insulating layer 7 (see FIG. 2A). Therefore, the display surface viewed from the observer (the second substrate 4 side) is a black display that is the color of the insulating liquid 1.

  On the other hand, by changing the polarity of the voltage applied to the electrode, the second electrode 6 is set to 0 V and the first electrode 5 is set to the positive electrode (+10 V), and the step is performed in the electrode plane with respect to the positively charged colored charged magnetic particles 2. When an electrostatic force larger than the maximum value of the magnetic force that changes is applied, all the colored charged magnetic particles 2 move away from the first insulating layer 7 to the second insulating layer 8 side by the electrostatic force, and the second insulation The second insulating layer 8 is dispersed and adhered to the layer 8 and is covered with the colored charged magnetic particles 2 (see FIG. 2B). For this reason, the display surface viewed from the observer (second substrate 4 side) is displayed in white.

  Further, after the colored charged magnetic particles 2 are dispersed on the first insulating layer 7, when the second electrode 6 is set to 0V and the first electrode 5 is set to the positive electrode (+ 8V), approximately half of the colored charged magnetic particles 2 are electrostatically charged. The first insulating layer 7 is moved by force to the second insulating layer 8 and dispersed and attached to the second insulating layer 8, and approximately half of the second insulating layer 8 is covered with the colored charged magnetic particles 2 (see FIG. 2 (c)). For this reason, the display surface viewed from the observer (second substrate 4 side) is displayed in gray, which is a halftone.

  At this time, the colored charged magnetic particles 2 are not affected by the magnetic force in the in-plane direction during migration, and the portion covered with the colored charged magnetic particles 2 of the second insulating layer 8 is the magnetic member 10. And the colored charged magnetic particles 2 are directly above the portion where the force acting between the colored charged magnetic particles 2 is less than half of the maximum value of the magnetic force gradually changing in the in-plane direction of the electrode. In all display states, the response speed is 300 ms or less.

  Further, even after the application of voltage is stopped after such halftone display and left for 1 hour, no change in display state due to sedimentation of the colored charged magnetic particles 2 is observed. Further, since the colored charged magnetic particles 2 have a magnetization of 10% or less of the saturation magnetization when no external magnetic field is applied, the colored charged magnetic particles 2 during migration do not aggregate and good migration is observed.

1 is a diagram showing a schematic configuration of an electrophoretic display element which is an example of a particle movement type display element according to a first embodiment of the present invention. FIG. 6 illustrates a display operation of the electrophoretic display element. The figure which shows the manufacturing method of the said electrophoretic display element. The figure which shows the other structure of the said electrophoretic display element. The figure which shows the other structure of the said electrophoretic display element. The figure which shows schematic structure of the electrophoretic display element which concerns on the 2nd Embodiment of this invention. The figure explaining the display operation of the conventional electrophoretic display element.

Explanation of symbols

1, 51 Insulating liquid 2, 52 Colored charged magnetic particles 3, 53 First substrate 4, 54 Second substrate 5, 55 First electrode 6, 56 Second electrode 7, 57 First insulating layer 8 Second insulating layer 9 , 58 Bulkhead 10,59 Magnetic member

Claims (9)

Colored charged magnetic particles are arranged between a first substrate and a second substrate arranged with a gap, and the colored charged magnetic particles are arranged between the first electrode and the second electrode arranged to face the gap. In a particle movement type display element that displays an image by moving in a gap by an electric field generated in
The movement of the colored charged magnetic particles to the other substrate side of the first substrate and the second substrate is regulated by a magnetic force on one substrate side of the first substrate and the second substrate, and the first electrode and the second substrate Providing a magnetic member configured to generate different magnetic fields stepwise along an electrode on one substrate side of the two electrodes;
Of the colored charged magnetic particles collected on the one substrate side and subjected to electrostatic force due to the electric field generated between the first electrode and the second electrode, the magnetic force acting between the colored charged magnetic particles and the magnetic member A particle movement type display element, characterized in that colored charged magnetic particles receiving a large electrostatic force are moved to the other substrate side.   A plurality of the magnetic members are juxtaposed in a direction along the electrode on the one substrate side, and are formed so that the lengths in the direction along the electrode on the one substrate side are stepwise different. The particle movement type display element according to claim 1.   A plurality of the magnetic members are juxtaposed in a direction along the electrode on the one substrate side, and are formed such that intervals in the direction along the electrode on the one substrate side are stepwise different. The particle movement type display element according to claim 1.   2. The particle movement type display element according to claim 1, wherein the magnetic member is formed such that the length in the normal direction of the electrode on the one substrate side is stepwise different.   2. The particle movement type display element according to claim 1, wherein the magnetic member has magnetic characteristics that differ stepwise in a direction along the electrode on the one substrate side.   6. The particle movement type display element according to claim 1, wherein the colored charged magnetic particles have substantially zero magnetization when no external magnetic field is applied.   The gap between the first substrate and the second substrate is filled with an insulating liquid, and the colored charged magnetic particles are dispersed in the insulating liquid. The particle movement type display element of description.   8. A partition wall for holding a gap between the first substrate and the second substrate is provided, and another electrode of the first electrode and the second electrode is provided on the partition wall. 2. A particle movement type display element according to item 1. A particle movement type display device comprising the particle movement type display element according to any one of claims 1 to 8.

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