JP3213591B2 - Magnetophoretic display device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the magnetic particles encapsulated in the display device by applying a magnetic field to magnetic migration relates to a magnetic migration type display device for some indication.

[0002]

2. Description of the Related Art For example, JP-A-53-127032, JP-A-52-30196, and JP-A-55-25.
Japanese Patent Laid-Open No. 934 discloses a magnetophoretic monochrome display device. In such a magnetophoretic monochrome display device, the sealed space between the front panel sheet and the back panel sheet is divided into a large number of cells, and a dispersion liquid containing black magnetic particles and a white fluid is sealed in each cell. .
By moving a magnetic member for recording etc. in contact with the outer surface of the front panel sheet, the black magnetic particles in the dispersion liquid sealed in the cell corresponding to the trajectory of the pen are moved by the magnetic field of the pen. Magnetophoresis from the bottom to the surface panel sheet side. As a result, some monochrome display is performed on the outer surface of the transparent top panel sheet due to the difference in contrast between the white fluid and the black magnetic particles.

Japanese Patent Publication No. 8-7532 discloses various black magnetic particles in a dispersion liquid sealed in a magnetophoretic monochrome display device in order to obtain a good monochrome image display on the outer surface of the front panel sheet. The conditions are described.

Recently, utility model registration No. 30471 has been proposed.
As shown in Japanese Patent Publication No. 70-70, a magnetophoretic color display device capable of displaying a plurality of colors has also been proposed.

[0005]

However, in such a conventional magnetophoretic display device, a vinyl chloride resin is used as a surface panel sheet.
There were issues regarding disposal. Further, in the magnetophoretic display device, there is a demand for an improvement in black-and-white contrast or color contrast by eliminating display cutoff at a boundary portion (boundary portion) of each cell.

In particular, there is a demand for a magnetophoretic color display device that has no color bleeding, has a clear color tone, and can improve the resolution of a color display image. The conventional magnetophoretic display device has not been able to sufficiently satisfy these requirements.

The present invention has been made in view of such circumstances, is environmentally friendly at the time of disposal, and has a magnetic field capable of preventing display cutoff at a boundary portion (boundary portion) of each cell and improving contrast. electrophoretic display device
The first object is to provide A second object of the present invention is to provide a magnetic device capable of eliminating display cutoff at a boundary portion (boundary portion) of each cell, eliminating color bleeding, having a clear color tone, and improving the resolution of a color display image. An object of the present invention is to provide a migration type color display device.

[0008]

Means for Solving the Problems The present inventors have proposed the first method.
As a result of intensive studies to achieve the object, the material of the top panel sheet, the thickness of the sealed space between the top panel sheet and the back panel sheet, the magnetic member for recording and the
By identifying the effective magnetic flux density of the magnetic member, etc. , it was found that it is environmentally friendly at the time of disposal, and it is possible to eliminate the display cutoff at the boundary (boundary part) of each cell and improve the contrast. The invention has been completed.

The present inventors have conducted intensive studies to achieve the second object and found that various conditions for the colored magnetic particles,
By maintaining the various conditions of the dispersion liquid in a predetermined relationship comprehensively, display cutoff at the boundary (boundary) of each cell is eliminated, color bleeding is eliminated, and the color tone is sharpened and the color display image is reduced. Of the present invention can be improved, and the present invention has been completed.

That is, a magnetophoretic display device according to the present invention comprises: a transparent front panel sheet made of polyethylene terephthalate; and a back panel sheet disposed so as to form a sealed space between the front panel. A partition member that is provided between the front panel sheet and the back panel sheet, and that divides the sealed space having a thickness of 0.8 to 1.5 mm into a number of cells, and inside each cell partitioned by the partition member. Dispersion liquid containing magnetic particles to be encapsulated and moves along the outer surface of the top panel sheet
It is possible to contact the outer surface of the top panel sheet
In the state, the effective magnetic flux density on the outer surface of the back panel sheet
With a magnetic force of about 100 to 500 Gauss
A recording magnetic member and an outer surface of the back panel sheet.
In the state where it is arranged on the outer surface of the back panel sheet,
The effective magnetic flux density on the outer surface of the top panel sheet is 300
Erase magnet with magnetic force of about 1500 Gauss
A magnetic member , wherein the average particle size of the magnetic particles is 50 to 200 μm, and the magnetic field applied to the magnetic particles is 500 (O
e) the magnetization of the magnetic particles is 20.0 emu / g or more, the dispersion liquid is a liquid in which colored magnetic particles are dispersed in a single color fluid, and the viscosity of the single color fluid is 25
At 200 ° C., the monochromatic fluid comprises at least a dispersing medium and a monochromatic pigment,
When the total weight of the single color fluid is 100% by weight, the weight% of the dispersion medium in the single color fluid is A, and the weight% of the single color tone pigment in the single color fluid is B, the weight ratio A /
B is characterized in that 10 ≦ A / B ≦ 20.

In the present invention, the partition member is not particularly limited, but is preferably made of a material in which paper is coated with a resin, and is a honeycomb structure having a large number of substantially regular hexagonal cylindrical cells. Preferably, there is.
Alternatively, the partition member may be a microcapsule capable of enclosing a dispersion liquid.

[0012]

[0013]

The single color fluid is preferably a color having a high contrast to the color of the magnetic particles, and is not particularly limited, but is preferably a white fluid.

The white fluid is not particularly limited, but preferably contains at least isoparaffin and a mixture of a plurality of white tone inorganic oxides .

Further, according to the present invention, the component in the single color fluid is
The dispersion medium is not limited to isoparaffin,
Media, including white-tone inorganic oxidized pigments.
Not only things, including other pigments, dyes, colorants, etc.
It is not limited to white.

The dispersion liquid includes a first dispersion liquid containing first colored magnetic particles sealed in a specific cell selected from cells partitioned by the partition member, and the first dispersion liquid. And a second dispersion liquid containing second colored magnetic particles different in color from the first colored magnetic particles, which is enclosed in a selected specific one of the cells not enclosed. It is preferred that it is constituted.

[0018]

In the present invention, the specific shape of the magnetic member for recording is not particularly limited, and any shape such as a magnetic pen or a magnetic stamp can be adopted.

[0020]

Preferably, the erasing magnetic member is movably disposed along an outer surface of the back panel sheet.

In the magnetophoretic display device according to the present invention, in addition to the first dispersion liquid and the second dispersion liquid, a third coloring different from the first coloring magnetic particles and the second coloring magnetic particles may be performed. It may have a third dispersion liquid containing magnetic particles. In this case, the colors of the first to third colored magnetic particles are different from each other, and are preferably three primary colors (red, green, and blue).
Is preferably any one of the following. Further, the magnetophoretic display device according to the present invention may include a dispersion liquid containing magnetic particles colored differently from the first to third colored magnetic particles, in addition to the first to third colored magnetic particles.

[0023]

According to the present invention, since the surface panel sheet is made of polyethylene terephthalate (PET),
It is easier to dispose of than a surface panel sheet made of vinyl chloride, and is more environmentally friendly. In addition, the present inventors have found that, by configuring the material of the front panel sheet by PET, the contrast on the panel display surface is improved.

In the present invention, the thickness of the sealed space is 0.8 to 1.5 mm, more preferably 1.00 to 1.5 mm.
1.40 mm. If the thickness is too small, single color particles (eg, white particles) in the single color fluid to adjust the single color chromaticity (eg, whiteness) of the single color fluid to hide the color tone of the magnetic particles in the cell. Must be contained in large amounts. As a result, the viscosity of the single-color fluid increases, so that the magnetic migration of the magnetic particles does not occur smoothly, and it is necessary to increase the magnetic flux density of the recording magnetic member and the erasing magnetic member. Further, the resolution and color tone of a display object displayed on the display surface of the display device tend to be inferior.

If the thickness of the sealed space is too large, the magnetic particles are required to be sufficiently electrophoresed on the surface panel sheet side in the cell. It is necessary to increase the magnetic flux density of the member. Further, the magnet mounted on the recording or erasing magnetic member is also expensive. In addition, the resolution of a display object displayed on the display surface of the display device tends to be poor.

In the present invention, the average particle size of the magnetic particles is 50 to 200 μm, more preferably 75 to 200 μm.
150 μm. If the average particle size of the colored magnetic particles is too small, a single color fluid (white fluid), which is the back color, is likely to be contaminated by the influence of the magnetic particles, and the response of the magnetophoresis when erasing the image display is slow. Tend to be. Also,
If the average particle size of the magnetic particles is too large, display is possible, but the resolution of display tends to deteriorate.

In the magnetic particles used in the present invention, when the magnetic field applied to the magnetic particles is 500 (Oe), the magnetization of the colored magnetic particles is preferably 20.0 emu / g or more.
More preferably, it is 22.0 emu / g or more. The magnetic particles need to have a magnetization such that the magnetophoresis is performed in the action of the low magnetic field of the recording magnetic member or the erasing magnetic member. The display and / or erasing action on the display surface of the display device is improved.

In the present invention, a single color fluid (white fluid)
Has a viscosity of preferably 200 to 80 at 25 ° C.
0 cp, and more preferably 300 to 600 cp.
If the viscosity of the single-color fluid (white fluid) is too low, the single color (white fluid) of the single-color fluid (white fluid) will be weakened, and when erasing the image (displaying a single color on the display surface), Color cannot be completely hidden from the display surface. If the viscosity of the single color fluid (white fluid) is too high, the single color (whiteness) of the single fluid (white fluid) obscures the color tone of the magnetic particles, and a clear color tone display cannot be obtained. Magnetophoresis of magnetic particles does not occur smoothly, and it is necessary to increase the magnetic flux density of the recording magnetic member and the erasing magnetic member.

[0029]

In the present invention, the dispersion in the single color fluid is
A single tone pigment in the single color fluid, wherein A is the weight% of the medium
And the weight ratio A / B is 10 ≦ A
/ B ≦ 20.

If the weight ratio A / B is too large , the whiteness (single color) of the white fluid (single color fluid) is weak, and the magnetic particles can be completely erased from the panel display surface when the displayed image is erased. No, the panel display surface tends to look dirty. On the other hand, if A / B is too small , the whiteness (single color) of the white fluid (single color fluid) obscures the color tone of the magnetic particles, and a clear color tone display tends not to be obtained.

In the recording magnetic member that can be used in the magnetophoretic display device of the present invention, the recording magnetic member is in contact with the outer surface of the top panel sheet, and is effective on the outer surface of the back panel sheet. Magnetic flux density is 100 ~
It has a magnetic force of about 500 Gauss . Further, in the erasing magnetic member that can be used in the magnetophoretic display device of the present invention, in a state where the erasing magnetic member is arranged on the outer surface of the back panel sheet, the effective magnetic flux on the outer surface of the front panel sheet is reduced. Density is 300 to 1500 Gauss
It is preferable to have a magnetic force of about s.

If the magnetic force of the recording magnetic member is too small, it is difficult to perform color display on the display surface because the magnetophoretic action in the cell is weak. On the other hand, if the magnetic force of the recording magnetic member is too large, the magnetic field is too strong, and the resolution of the display object tends to be degraded when the magnetized particles are displayed on the panel surface.

If the magnetic force of the erasing magnetic member is too small, the magnetophoretic action in the cell is weak, and it is difficult to pull back the magnetic particles from the panel display surface side. It tends to be difficult. Also, if the magnetic force of the erasing magnetic member is too large, the magnetic field is too strong, and the magnetic particles that have been magnetophoresed for erasing will remain on the inner surface of the panel display surface as earing phenomena. Tend to be unable to erase cleanly.

In the present invention, as described above, the thickness of the sealed space, the particle size of the magnetic particles, the magnetization characteristics, the viscosity and composition of the single-color fluid (white fluid), and / or the recording magnetic member and the erasing magnetic member By restricting the specific area in the effective magnetic flux density, etc., it is possible to obtain a magnetophoretic display device in which the display on the panel display surface, in particular, the color display is made clear and the erasure can be made clear.

Further, according to the manufacturing method of the present invention, a magnetophoretic display device which is easy to dispose, is friendly to the global environment, and can improve the contrast on the display surface can be manufactured very easily. can do.

The use of the magnetophoretic display device according to the present invention is not particularly limited, and toys for infants, teaching materials, calligraphy boards, various game boards, recording bulletin boards, memo boards, blackboards, whiteboards, advertising boards, It can be widely used as a portable notepad. The installation location of the magnetophoretic display device according to the present invention is not particularly limited, and is not limited to the inside of a building such as a factory or a school. The platform may be a station platform, a ticket gate, an outdoor site such as a construction site, or underwater. Is also good.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings. FIG. 1 is a sectional view of a magnetophoretic color display device according to one embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part corresponding to a unit cell of the magnetophoretic color display device, and FIG. 3 is a honeycomb as a partition member. FIG. 4 is a perspective view of the structure, FIG. 4 is a cross-sectional view of a main part showing a manufacturing process of the magnetophoretic color display device, and FIGS. 5A to 5C are plan views of a mask sheet used in the manufacturing process of the magnetophoretic color display device. FIG. 6 (D) is a schematic view showing a pattern obtained by dividing the display surface for each color, FIGS. 6 (A) and 6 (B) are schematic views showing a process for manufacturing a honeycomb structure, and FIGS. (C) is a schematic diagram showing evaluation criteria in the example of the present invention.

As shown in FIG. 1, the magnetophoretic color display device 2 according to one embodiment of the present invention comprises at least a magnetic display panel 20, a recording magnetic pen 16 as a recording magnetic member, and an erasing magnetic pen. Magnetic erasing lever 1 as a member
8 is provided.

The magnetic display panel 20 has a top panel sheet 4 and a back panel sheet 6, and the outer peripheries of the sheets 4 and 6 are heat-sealed or bonded to each other. A sealed space 8 is formed therebetween. In the closed space 8, a honeycomb structure 10 as a partition member is arranged. As shown in FIG. 3, the honeycomb structure 10 has a large number of substantially regular hexagonal cylindrical cell spaces 15. As shown in FIG. 1, inside each cell space 15 surrounded by the sheets 4 and 6, a first dispersion liquid 12a containing first colored magnetic particles 14a, a dispersion liquid 12b containing second colored magnetic particles 14b, And any of the third dispersion liquids 12c containing the third colored magnetic particles 14c. Which cell space 15 is to be filled with any of the dispersion liquids 12a to 12c is arbitrary. However, according to a method described later, a large number of cell spaces 15 constituting the display surface are divided into, for example, three blocks, and each block is divided into three blocks. Different dispersion liquids 12a to 1
It is preferable to encapsulate 2c. Each dispersion liquid 12a, 1
Each cell space 15 in which 2b or 12c is enclosed is shown in FIG.
The single display cell 30 shown in FIG.

In the color display device 2, the tip of the magnetic pen 16 is slid on the display surface 4 a, which is the surface of the front panel sheet 4, so that the display corresponding to the locus of the movement of the magnetic pen 16 is performed. Colored magnetic particles 14 in cell 30
A magnetic field acts on the colored magnetic particles 14a to 14c.
The magnetophoresis c occurs inside the cell 30, and a color display is performed on the display surface 4a. To erase the display on the display surface 4a, the magnetic lever 18 is moved at the bottom of the magnetic display panel 20 to erase the color display on the display surface 4a of the magnetic panel 20.

A permanent magnet 17 is held at the tip of the magnetic pen 16, and a permanent magnet 19 is also held at the magnetic lever 18. The magnetic pen 16 is not connected to the magnetic display panel 20 and is provided as a separate member. The magnetic lever 18 is arranged so as to be movable along the outer surface of the back panel sheet 6 in advance to be connected to the magnetic display panel 20. The operation of the magnetic lever 18 may be manually performed by an operator's hand, or may be automatically performed by connecting a drive device such as a motor actuator to the magnetic lever and operating an operation button or the like.

Although not shown in FIG. 1, it is preferable that the outer periphery and the back surface of the magnetic display panel 20 be covered and protected by a synthetic resin casing or the like. The magnetic lever 18 is preferably movably connected to the casing. An opening is formed in the casing, and the display surface 4a of the magnetic display panel 20 is exposed.

When the magnet 17 of the magnetic pen 16 is in contact with the outer surface of the front panel sheet 4, the effective magnetic force on the outer surface of the back panel sheet 6 is changed.
It has a magnetic force such that the flux density becomes 100 to 500 Gauss. Also, the magnet 19 of the erasing magnetic lever 18 is in a state in which the magnet 19 of the magnetic lever 18 is disposed on the outer surface of the back panel sheet 6, the actual at the outer surface of the front panel sheet 4
It has a magnetic force such that the effective magnetic flux density becomes 300 to 1500 Gauss.

If the magnetic force of the magnet 17 of the recording magnetic pen 16 is too small, it is difficult to perform color display on the display surface 4a because the magnetophoretic action in the cell 30 is weak. If the magnetic force of the magnet 17 of the recording magnetic pen 16 is too large, the magnetic field is too strong.
When a to c are displayed on the panel display surface 4a, the resolution of the color display object tends to be deteriorated.

On the other hand, if the magnetic force of the magnet 19 of the erasing magnetic lever 18 is too small, the magnetophoretic action in the cell 30 is weak, and the colored magnetic particles 14a to 14 from the panel display surface 4a side.
It is difficult to pull back c, and there is a tendency that it is difficult to erase a display object on the display surface 4a. If the magnetic force of the magnet 19 of the erasing magnetic lever 18 is too large, the magnetic field is too strong.
Since 4a to 14c remain on the inner surface of the panel display surface 4a as a spike phenomenon, there is a tendency that the display on the panel display surface 4a cannot be erased cleanly.

The materials of the magnets 17 and 19 are not particularly limited, and known materials may be used. For example, a magnet made of ferrite powder (magnet plumbite type ferrite) or metal powder (single or alloy of Nd, Sm, Co, Fe, Ni, etc.) or a magnet formed by adding rubber or resin to these materials is used. Just choose.

In the magnetic display panel 20 of the display device 2 according to the present embodiment, the front panel sheet 4 is formed of a transparent sheet, and the outer surface thereof becomes the panel display surface 4a. In this embodiment, the material of the front panel sheet 4 is made of polyethylene terephthalate. The magnetic display panel 20 having the surface panel sheet 4 made of polyethylene terephthalate is easy to dispose of and is friendly to the natural environment. Further, when the front panel sheet 4 is made of polyethylene terephthalate, the color contrast on the display surface is improved.

The thickness of the front panel sheet 4 is not particularly limited, but is preferably 0.10 to 0.50 mm, and more preferably 0.15 to 0.25 mm. If the thickness of the front panel sheet 4 is too small, the durability of the magnetic pen 16 against friction tends to decrease. If the thickness is too large, material is wasted. The front panel sheet 4 is
It may be a multilayer sheet.

The back panel sheet 6 is not necessarily required to be transparent, and its material is not particularly limited.
For example, vinyl chloride, polyethylene terephthalate (P
ET), a synthetic resin such as polyester or polyethylene, and preferably a PET. The thickness of the back panel sheet 6 is not particularly limited, but is preferably 0.05 to 0.30 mm, and more preferably 0.10 mm.
０．２0.20 mm. If the thickness of the back panel sheet 6 is too small, durability tends to decrease, and if the thickness is too large, material is wasted. This back panel sheet 6 may also be constituted by a multilayer sheet.

The honeycomb structure 10 shown in FIG. 3 is made of water-resistant special paper. The cross-sectional area of the substantially regular hexagon of each cell space 15 in the honeycomb structure 10 is not particularly limited, but is preferably 1.0 to 5.0 mm ² ,
More preferably from 2.0 to 3.0 mm ^2. The smaller the cross-sectional area is, the finer the display is. However, if the cross-sectional area is too small, smooth magnetic migration of the colored magnetic particles 14 in each cell 30 tends to be difficult. Tends to be difficult. In the present embodiment, such a honeycomb structure 10 is used because it has a structure capable of increasing the resolution of a display object on the display surface 4a and has excellent strength. Further, when the honeycomb structure 10 is made of paper, the magnetic display panel 20 can be easily disposed of. A method for manufacturing the honeycomb structure 10 will be described later.

The thickness of the partition partitioning each cell space 15 of the honeycomb structure 10 is not particularly limited, but is preferably 0.01 to 0.5 mm, and more preferably 0.03 to 0.5 mm.
0.1 mm. The thickness of the partition wall is preferably as small as possible from the viewpoint of preventing interruption of a display object on the display surface 4a, but if it is too thin, the strength tends to decrease.

The height H (see FIG. 3) of the honeycomb structure 10 corresponds to the thickness T of the sealed space 8 shown in FIG. In the present embodiment, the thickness T is 0.8 to 1.5 mm. If the thickness is too small, it is necessary to contain a large amount of white fine particles in the white fluid in order to adjust the whiteness of the white fluid for hiding the color tone of the colored magnetic particles 14a to 14c in the cell 30. As a result, the viscosity of the white fluid increases, and the magnetic migration of the colored magnetic particles 14a to 14c does not occur smoothly. Therefore, it is necessary to increase the magnetic flux density of the magnet 17 or 19 in the magnetic pen 16 or the magnetic lever 18. Further, the resolution and the color tone of the display object displayed on the display surface 4a of the display device tend to be adversely affected.

If the thickness of the sealed space T is too large,
In order to sufficiently cause the colored magnetic particles 14a to 14c to be electrophoresed on the front panel sheet 4 side or the rear panel sheet 6 side in the cell 30, the magnet pen 16 or the magnet 17 in the magnetic lever 18 is used because the magnetic migration distance is long. Or 19
Needs to be increased in magnetic flux density. In addition, these magnets 17 or 19 are also expensive.

As shown in FIG. 2, the dispersion liquids 12a to 12c sealed in each cell 30 are contained in a white fluid.
These are liquids in which the colored magnetic particles 14a to 14c are dispersed. The white fluid contains at least a white pigment (including a dye) and a dispersion medium. The white pigment is not particularly limited, and examples thereof include titanium oxide, alumina, zinc oxide, silica, barium titanate, and barium zirconate. In the present embodiment, titanium oxide (Ti
O ₂ ), alumina (Al ₂ O ₃ ), zinc oxide (Z
White inorganic inorganic oxides such as nO) and silica (silicon oxide: SiO ₂ ) are preferably used. The dispersion medium is not particularly limited, and examples thereof include a polar dispersion medium such as water and glycols, and a nonpolar dispersion medium such as an organic solvent and oil. In the present embodiment, preferably, paraffins are used. (Especially isoparaffin) is used.

In this embodiment, the total weight of the white fluid is 10
0% by weight, the weight% of isoparaffins in this white fluid is A, and the weight% of the mixture of white-tone inorganic oxides is B
, The weight ratio A / B is in a relationship of 10 ≦ A / B ≦ 20.

If the weight ratio A / B is too large, the whiteness of the white fluid is weak, and the colored magnetic particles 1
4a to 14c cannot be completely erased from the panel display surface 4a, and the panel display surface 4a tends to look dirty. On the other hand, if the A / B is too small, the whiteness of the white fluid will obscure the color tone of the colored magnetic particles 14a to 14c, and a clear color tone display will not be obtained.

In the present embodiment, the viscosity of the white fluid is 200 to 800 cp at 25 ° C.
If the viscosity of the white fluid is too low, the whiteness of the white fluid becomes weak, and the color of the colored magnetic particles 14a to 14c is completely hidden from the display surface 4a when erasing an image (displaying white on the display surface 4a). Can not. If the viscosity of the white fluid is too high, the whiteness of the white fluid will obscure the color tone of the colored magnetic particles 14a to 14c, and a clear color tone display will not be obtained. It does not occur smoothly, and the recording magnetic pen 16 and the erasing magnetic lever 18
It is necessary to increase the magnetic flux density of the magnet 17 or 19 of FIG.

In this embodiment, each of the dispersion liquids 12a to 12a
c, colored magnetic particles 14a to 14c contained together with a white fluid.
14c is not particularly limited as long as it is colored differently, and various colored fine particles can be used. For example, as the colored magnetic particles 14a to 14c, fine particles obtained by coating the outer peripheral surface of a magnetic substance such as a ferrite powder or a metal powder with a synthetic resin or a coloring agent can be used.

The material of the magnetic material in the colored magnetic particles 14a to 14c is such that the magnetization of the colored magnetic particles 14a to 14c is 20.0 emu / g or more when the applied magnetic field to the colored magnetic particles 14a to 14c is 500 (Oe). It is selected from such materials. The material of such a magnetic body is not particularly limited, and oxide magnetic materials such as black magnetite, chromium dioxide, and ferrite (spill-type ferrite, magnetoplumbite-type ferrite), cobalt, iron, copper, nickel, or Examples thereof include metal magnetic materials such as alloys thereof, and metal magnetic materials are preferable.

The colored magnetic particles 14a to 14c need to have such a degree of magnetization that magnetophoresis can be performed by the action of the low magnetic field of the recording magnetic pen 16 or the erasing magnetic lever 18, and the magnetic susceptibility in the above-mentioned range. With this, the colored magnetic particles 14a to 14c are sufficiently subjected to magnetophoresis, and the display and / or erasing action on the display surface 4a of the display device is improved.

Known synthetic resins may be used as the synthetic resin contained in the colored magnetic particles 14a to 14c.
It may be selected from styrene, polyester, acrylic, epoxy, and the like. As the colorant, a known inorganic or organic pigment depending on the color to be colored may be used. For example, the colored magnetic particles 14a to 14c may be used.
When any of the above is black, carbon black is used. When the colored magnetic particles 14a are blue magnetic particles, the colored magnetic particles 14b are green magnetic particles, and the colored magnetic particles 14c are red magnetic particles, the following colorants are preferably used. That is, as the blue colorant, a colorant such as a Co-Mn-based composite oxide pigment is preferable. Further, as a green colorant, Co-Mn
A colorant such as a complex oxide pigment is preferred. Further, as the red colorant, a colorant such as hematite is preferable.

It is preferable that the synthetic resin and / or the colorant in the colored magnetic particles 14a to 14c form a coating layer for coating the magnetic powder. When the magnetic material powder is not covered with the coating layer, the resistance to abrasion is reduced, which tends to cause coloring of the display surface. Also,
The colored magnetic particles 14a to 14c are each dispersed liquid 12a to 1c.
In 2c, the type of the synthetic resin and / or the colorant must be
A resin that does not cause softening or swelling is selected, and a synthetic resin partially cross-linked with a cross-linking agent (for example, a urethane modifier) can also be used.

In this embodiment, each of the colored magnetic particles 14a to 14a
The weight ratio of the magnetic material to the synthetic resin and / or the colorant in 14c varies depending on the color tone of each of the particles 14a to 14c, but generally, 60 to 90% by weight of the magnetic material and 10 to 40% by weight. It is preferable that the weight ratio is based on the weight of the synthetic resin and / or the colorant.

In this embodiment, the colored magnetic particles 14a
The average particle size of １４14c is 50-200 μm. Such colored magnetic particles 14a to 14c may be spherical or irregularly shaped other than spherical, and can be obtained by a conventional general manufacturing method. For example, after melt-mixing the above-mentioned composition comprising the synthetic resin and / or the colorant and the magnetic material, pulverize, classify by wind and classify.
Colored magnetic particles 14a to 14c of 0 to 200 μm are obtained.
Alternatively, a similar composition is mixed in a solvent, dried and classified, and the colored magnetic particles 14a having a size of 50 to 200 μm are mixed.
To 14c. If the average particle size of the colored magnetic particles is too small, the white fluid that is the back color will be
14c tends to cause contamination, and the responsiveness of magnetophoresis when erasing an image display tends to be slow. If the average particle size of the colored magnetic particles 14a to 14c is too large, color display is possible, but the resolution of color display tends to deteriorate.

In the present embodiment, the mixing ratio of the white fluid and the colored magnetic particles 14 a to 14 c in the dispersion liquids 12 a to 12 c sealed in each cell 30
Although it differs depending on the color tone of a to 14c, in general, 8
It is preferable that the weight ratio is 0 to 90% by weight of the white fluid and 10 to 20% by weight of the colored magnetic particles 14a to 14c. Colored magnetic particles 14a to 14c in dispersion liquid
Is too low, the colored magnetic particles 14a to 14c
, The resolution of the display object on the display surface 4a of the display device tends to be poor. For example, the thickness of a line or a character becomes thin, and the line or the character may be interrupted. On the other hand, if the content ratio of the colored magnetic particles 14a to 14c is too high, the density of the display substance on the display surface 4a of the display device can be increased, but the white fluid is easily contaminated. Is a factor that weakens the white color, and tends to cause a decrease in color contrast.

In order to manufacture the magnetophoretic type color display device 2 according to the present embodiment, first, as shown in FIG. 4, a concave portion 4b of a front panel sheet 4 made of transparent PET having a concave portion 4b on the inner surface side. The honeycomb structure 10 is housed. The honeycomb structure 10 according to the present embodiment is made of special paper. As shown in FIG. 6A, in a state before mounting, the honeycomb structure 10 is contracted in one direction to form a honeycomb preformed block 10a. I have. A tensile force F is applied from both ends of the honeycomb preformed block 10a, as shown in FIG.
The block 10a is expanded, and each cell space 15 is opened.

For example, in the state of the block 10a, the length L1 in one direction is preferably 3.0 to 5.0 cm, more preferably 3.5 to 4.5 cm, and the length L2 Is preferably 40-60 cm,
More preferably, it is 45 to 58 cm. In addition, the opening length L3 of each cell space 15 in the elongated structure 10 is preferably 2.5 to 5.0 mm, more preferably 2.8 to 4.2 mm. The tensile force F for performing such opening changes according to the size of the honeycomb structure 10 and the like, and is not particularly limited.
It is about 100 gf. If this tensile force is too small,
There is a tendency that the cell space 15 cannot be opened well, and if it is too large, the honeycomb structure 10 may be damaged.

The aperture length L3 in each cell space 15 is
Since the honeycomb structure 10 tends to shrink with the passage of time together with the length L2 of the honeycomb structure 10, in the present embodiment, the solidifying agent is applied to the honeycomb structure 10 after the release of the tensile force F (for example, after several tens of seconds). Is spray applied. As a solidifying agent,
The solidifying agent is not particularly limited as long as the solidifying agent can suppress the contraction of the shape of the elongated honeycomb structure 10. For example, the solidifying agent is made of a solution obtained by dissolving an acrylic resin such as a styrene-acryl copolymer in ethyl acetate. A solidifying agent is used. The weight ratio of ethyl acetate to the acrylic resin in the solidifying agent is not particularly limited, and it is preferable that the amount of the acrylic resin is about 10 to 20% by weight based on 80 to 90% by weight of ethyl acetate. By increasing the resin content, the structure 1
Although the effect of suppressing shrinkage of 0 can be expected to be high, if the content ratio of the resin is too high, spray application by a spray tends to be difficult.

The honeycomb structure 10 is cut into a predetermined size in a state where the cell space 15 is opened and the shrinkage of the honeycomb structure 10 is suppressed, as shown in FIG. The cut honeycomb structure 10 is housed and bonded in the recess 4b of the top panel sheet 4 having the recess 4b.

Thereafter, the first to first cells are placed inside each cell space 15.
The dispersion liquid 12a, 12b or 12c containing any one of the third colored magnetic particles 14a to 14c is separated according to a predetermined rule or randomly. In order to separate according to a predetermined rule, a method using a mask sheet or a mold in which a pattern opening for each predetermined coloring is formed,
A method using a masking tape, a method using screen printing, and the like are exemplified.
The mask sheets 50a to 50c shown in (A) to (C) are used.

The mask sheet 5 shown in FIGS.
0a to 50c respectively have a first coloring opening 52.
a, second coloring opening 52b and third coloring opening 5
2c is formed. These openings 52a to 52c are
Each has a pattern that does not overlap.

For example, the mask sheet 50a having the openings 52a is positioned and placed inside the front panel sheet 4 in which the honeycomb structure 10 shown in FIG. 4 is stored. Next, a plurality of cell spaces 1 divided into blocks located in a pattern corresponding to the opening 52a of the mask sheet 50a.
5 is filled with the first dispersion liquid 12a containing the first colored magnetic particles 14a.

Next, the mask sheet 50a is removed, and the mask sheet 50b having the openings 52b of another pattern is formed.
Is positioned and placed inside the front panel sheet 4 in which the honeycomb structure 10 shown in FIG. 4 is accommodated. Next, the second dispersion liquid 12b containing the second colored magnetic particles 14b is filled into the inside of the blocked multiple cell spaces 15 located in the pattern corresponding to the openings 52b of the mask sheet 50b.

Next, the mask sheet 50b is removed, and the mask sheet 50c having the openings 52c of another pattern is formed.
Is positioned and placed inside the front panel sheet 4 in which the honeycomb structure 10 shown in FIG. 4 is accommodated. Next, the third dispersed liquid 12c containing the third colored magnetic particles 14c is filled into the inside of the blocked multiple cell spaces 15 located in the pattern corresponding to the openings 52c of the mask sheet 50c.

Thereafter, the mask sheet 50c is removed, and FIG.
As shown in (2), the back panel sheet 6 with the adhesive 42 applied to the inner surface is pressed and adhered to the upper surface of the honeycomb structure 10 in the drawing and the inner peripheral surface of the front panel sheet 4. Next, using a high-frequency welder, a part 40 of the outer periphery of the front panel sheet 4 is thermally welded to completely seal the inside, and the magnetic display panel 20 shown in FIG. 1 is obtained. The conditions for heat welding with a high-frequency welder are not particularly limited, but are preferably 80 to 110 ° C., and more preferably 9 to 110 ° C.
At a heating temperature of 5 to 105 ° C, it is preferably 3 to 7 seconds, more preferably 4 to 6 seconds. If the heating temperature is too low, it tends to be difficult to heat seal the top panel sheet 4 made of PET, and if the heating temperature is too high, it tends to adversely affect the internal dispersion liquids 12a to 12c. 1 and 4, the magnetic display panel 20 is shown upside down.

According to such a method, as shown in FIG. 5 (D), the entire display surface 4a is divided into three blocks of a predetermined pattern, and different color tones are placed inside the cell space 15 located in each block. Colored magnetic particles 14a to 14c
Can be manufactured, which can display a plurality of colors by dispersing liquids 12a to 12c containing the same.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention.

For example, the partition member for dividing the inside of the magnetic display panel 20 into a plurality of cells 30 is not limited to the honeycomb structure shown in FIG. 3, but may use microcapsules or other partition members. it can.

The recording magnetic member as the recording magnetic pen 16 shown in FIG. 1 may be connected to the magnetic display panel 20 by a string or the like without being completely separated. Further, the recording magnetic member serving as the recording magnetic pen 16 can be automatically moved by an XY plotter or the like without being manually moved.

The color tones of the colored magnetic particles 14a to 14c are not limited to the three primary colors, but may be other colors.
Further, the types of the colored magnetic particles are not limited to three types, but may be two types or four or more types. Further, the color tone of the single color fluid which is the back color of the dispersion liquid in which these colored magnetic particles are dispersed is not limited to white, but may be other colors.

Further, in the above-described embodiment, the magnetophoretic color display device has been described.
The present invention is not limited to a magnetophoretic color display device, but can be applied to a monochrome type of electrophoretic display device such as a monochrome one.

[0083]

EXAMPLES Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples. In addition, wt% in a table | surface shows a weight%.

Preparation of Inclusions in the Panel Isoparaffin, titanium oxide, zinc oxide, silicon oxide and alumina were quantified to a predetermined composition as shown in Table 1 below, and then stirred at 4000 rpm for 5 minutes with a homogenizer stirrer. White fluids (white fluids) 1 to 7 were obtained. 100% by weight of the total weight% of these white fluids 1 to 7
%, And the weight% of isoparaffin in the white fluid is A.
When B is the weight percentage of a white oxide mixture comprising titanium oxide, zinc oxide, silicon oxide and alumina, A
Table 1 shows the ratio of / B. Table 1 shows the viscosity of each of the white fluids (white fluids) 1 to 7 at a temperature of 25 ° C. This viscosity was determined by using a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd.) and setting 500 cc of each white fluid.

[0085]

[Table 1]

Separately from the white fluids 1 to 7, colored magnetic powders 1 to 7 (corresponding to the colored magnetic particles 14a to 14c in FIGS. 1 and 2) having the compositions and magnetization characteristics shown in Table 2 below are prepared. Got ready.

[0087]

[Table 2]

In Table 2, the black magnetic powder 1 is a magnetic substance obtained by coating 70% by weight of a magnetic substance mainly composed of Fe with a colorant of 30% by weight of carbon and a synthetic resin of styrene-acrylic resin. The average particle size and magnetization characteristics of the particles are shown in Table 2.

The blue magnetic powder 2 is a magnetic material obtained by coating a magnetic material containing 85% by weight of Fe as a main component with a colorant composed of 15% by weight of a Co—Mn-based composite oxide and a synthetic resin composed of a polyester resin. The average particle size and magnetization characteristics of the particles are shown in Table 2.

The red magnetic powder 3 is a magnetic substance particle obtained by coating a magnetic substance containing 85% by weight of Fe as a main component with a coloring agent composed of 15% by weight of hematite and a synthetic resin composed of styrene-acryl resin. The average particle size and magnetization characteristics are shown in Table 2.

The green magnetic powder 4 is a magnetic material obtained by coating a magnetic material containing 80% by weight of Fe as a main component with a colorant comprising 20% by weight of a Co—Mn-based composite oxide and a synthetic resin comprising a polyester resin. The average particle size and magnetization characteristics of the particles are shown in Table 2.

The black magnetic powder 5 is a magnetic substance particle obtained by coating a magnetic substance containing 60% by weight of Fe as a main component with a colorant composed of 40% by weight of carbon and a synthetic resin composed of a polyester resin. The particle size and magnetization characteristics are shown in Table 2.

The black magnetic powder 6 is a magnetic substance particle obtained by coating a magnetic substance containing 75% by weight of Fe as a main component with a coloring agent composed of 25% by weight of carbon and a synthetic resin composed of styrene-acryl resin. The average particle size and magnetization characteristics are shown in Table 2.

The red magnetic powder 7 is a magnetic substance particle obtained by coating a magnetic substance composed of 65% by weight of magnetite with a synthetic resin composed of a coloring agent composed of 35% by weight of hematite and a polyester resin. The magnetization characteristics are shown in Table 2. The average particle size of the colored magnetic powders 1 to 7 was measured by placing the colored magnetic powder on each of the sieves having mesh numbers # 83 to # 325 and vibrating to determine the amount of the colored magnetic powder remaining on each sieve. The calculation was performed by calculating the average particle diameter from the ratio.

Next, the white fluid 1 prepared in Table 1 was prepared.
Are transferred to a plurality of separate containers, and colored magnetic powders 1 to 7 having compositions and magnetization characteristics shown in Table 2 are respectively added thereto. The mixture is stirred for 1 minute at 300 rpm using a stirrer. I got The addition amount of the colored magnetic powder in the dispersion liquid was 1 to 80 to 90% by weight of the white fluids 1 to 7.
0-20% by weight of colored magnetic powders 1-7. The combinations of the white fluid and the magnetic powder are shown in Table 3 below.

[0096]

[Table 3]

Preparation of Magnetic Display Panel As the surface panel sheet 4 shown in FIG.
m transparent PET sheet is prepared and the rear panel sheet 6 is prepared.
As a sample, a transparent PET sheet having a thickness of 0.10 mm was prepared and used as a panel sheet for panel samples 1 to 15 in Table 3. In addition, regarding only the panel sample 16 shown in Table 3, as the surface panel sheet 4 shown in FIG.
A transparent vinyl chloride sheet having a thickness of 0.20 mm was used. As the back panel sheet 6, a transparent vinyl chloride sheet having a thickness of 0.10 mm was used. Further, as the honeycomb structure 10 shown in FIG. 3, a honeycomb structure made of special paper is prepared.
It was used as a honeycomb structure for panel samples 1 to 16 in Table 3.

As shown in FIG. 6 (A), the honeycomb structure 10 has contracted in one direction before being mounted, and has become a honeycomb preformed block 10a. A tensile force F = 94 from both ends of the honeycomb preformed block 10a.
gf, and as shown in FIG.
0a was expanded, and each cell space 15 was opened.

In the state of the block 10a, the length L1 in one direction was 4.5 cm.
The length L2 of 0 was 57.6 cm. The opening length L3 of each cell space 15 in the structure 10 immediately after the stretching is 4.2 mm, and the opening length L3 is 30 mm immediately after the release of the tensile force F.
The opening length L3 after 2 seconds was 3.0 mm. In this state, the solidifying agent was spray-coated on the honeycomb structure 10. The solidifying agent used was a solution in which 20% by weight of a styrene-acrylic copolymer was dissolved in 80% by weight of ethyl acetate.

The honeycomb structure 10 is cut into a predetermined size in a state where the cell spaces 15 are opened in this way and the shrinkage of the honeycomb structure 10 is suppressed, and as shown in FIG. The cut honeycomb structure 10 was bonded in the recess 4b of the top panel sheet 4 having the recess 4b. At the time of bonding, a vinyl acetate-based adhesive was used.

In this state, the cross-sectional area of each cell space 15 in the honeycomb structure 10 is 3.0 mm ² , and the thickness of the partition partitioning each cell space 15 is 0.05 mm.
mm. Further, as the honeycomb structure 10, those having various heights H (see FIG. 3) were prepared. This height H corresponds to the thickness T of the sealed space 8 shown in FIG. 2, and various thicknesses (corresponding to the panel thickness in Table 3) were prepared as shown in Table 3 above. .

As shown in FIG. 4, after the lower end face of the honeycomb structure 10 is adhered to the inner face of the front panel sheet 4, each of the cell spaces 15 obtained in the process of producing the in-panel inclusion is placed inside each cell space 15. The fill was filled with stirring. When filling the enclosure, two types of panel samples 1 to 16 (excluding panel sample 5) shown in Table 3 were used for the same panel sample so that two or more colors could be displayed. The above colored magnetic powder was enclosed. At the time of this sealing, the display surface was divided into predetermined blocks using a masking tape, and a white fluid containing different colored magnetic powder was sealed in each block. As for the panel sample 5, a white fluid containing one type of magnetic powder 1 was sealed.

Thereafter, as shown in FIG. 4, the back panel sheet 6 coated with a vinyl acetate adhesive is bonded to the inner peripheral surface of the front panel sheet 4 and the other end surface of the honeycomb structure 10 while applying pressure. Was heated and heated at 100 ° C. for 5 seconds using a high-frequency welder, and the inside was completely sealed.
16 (corresponding to the magnetic display panel 20 shown in FIG. 1).

The obtained magnetic panels 1 to 16 were measured and evaluated as follows. The results are shown in Table 4 below. The measurement was performed as follows.

Measurement a. The magnetization of the colored magnetic powder sample was measured using a vibrating sample magnetometer (Model No. VSM-3 manufactured by Toei Kogyo Co., Ltd.), setting the colored magnetic powder sample in a holder, and applying a magnetic field of 5 to the holder.
The measurement was performed as 00 (Oe).

B. As shown in Table 3, the measurement of the effective magnetic flux density of the magnet used for the recording magnetic pen in the magnetic display panel was performed using the magnetic display panels 1 to 16 having a predetermined sealed space thickness (panel thickness). The tip of a magnetic pen was applied to the display surface, and the magnetic flux density on the outer surface of the back panel sheet of the magnetic display panel was determined using a handy type magnetometer (product number FS-5, manufactured by ADS Co., Ltd.). . Similarly, the effective magnetic flux density of the magnet used for the erasing magnetic arm was measured using magnetic display panels 1 to 15 having a predetermined sealed space thickness as shown in Table 3, and the erasing was performed on the outer surface of the back panel sheet. The magnetic flux density on the outer surface of the surface panel sheet of the magnetic display panel was measured using a hand-held magnetometer (ADS Co., Ltd., product number F).
S-5).

C. Measurement of reflectivity The reflectivity of the display surface of the magnetic display panel is measured using a reflectometer (product number REFLECTMETER manufactured by Tokyo Denshoku).
/ TC-6MC type), and directly measured the image displayed on the display surface of the magnetic display panel with a reflectometer. The reflectance was determined when white was displayed on the display surface of the magnetic display panel (the state in which the colored magnetic particles 14a to 14c shown in FIG. 2 were close to the inner surface of the back panel sheet 6).
In the case of white display, the higher the reflectance, the better. The results are shown in Table 4 below.

D. Resolution of Displayed Object The resolution of the displayed object on the display surface was visually confirmed. The blurring of the characters shown in FIG. 7A was observed. In the evaluation of the resolution of the display object in Table 4 below, ○ indicates that no blurring of characters was observed even in 10 repeated tests, and × indicates 5 times in 10 repeated tests. As described above, blurring of characters is observed.

E. Discontinuity of the display at the boundary part (boundary part) of each cell Boundary part (boundary part) of each cell on the magnetic display panel
The interruption of the display in the above was visually confirmed. In the evaluation of the break at the boundary for each cell in Table 4 below,
○ indicates that no break was observed at the boundary of each cell as shown in FIG. 7 (C) even in the 10 repeated tests, and × indicates 5 or more times in the 10 repeated tests. 7B shows that a break was observed at the boundary of each cell.

F. The sharpness of a plurality of colors when displaying on the panel display surface The sharpness of a plurality of colors when displaying on the panel display surface was visually confirmed. The sharpness of color tone and color blur were observed.

In the evaluation of the sharpness of a plurality of colors in Table 4 below, ○ indicates that the color tone was clear and no color bleeding was observed even after 10 times of repeated tests, and × indicates that
In 10 repetition tests, it is shown that unclear color tone or color bleeding was observed 5 times or more.

[0112]

[Table 4]

As can be understood from all of the above tables, the magnetophoretic color display device within the preferred numerical range of the present invention is more effective than the magnetophoretic color display device outside the preferred numerical range of the present invention. It is possible to eliminate display cutoff at a boundary portion (boundary portion) of each cell, eliminate color bleeding, have a clear color tone, and improve the resolution of a color display image.

As shown in Table 4, panel sample 1 and panel sample 16 were compared under the same conditions except that PET or vinyl chloride sheet was used as the material of the front panel sheet and the back panel sheet. by doing,
It was found that panel sample 1 using PET had higher panel white reflectance. By improving the panel white reflectance, an improvement in contrast in color display can be expected.

[0115]

As described above, according to the present invention, there is provided a magnetophoretic display device which can be easily disposed of, is friendly to the global environment, and can improve the contrast on the display surface. can do. Further, according to the present invention, it is possible to eliminate display cutoff at a boundary portion (boundary portion) of each cell, to prevent color bleeding, to obtain a clear color tone, and to improve the resolution of a color display image. A type color display device can be provided.

Further, according to the manufacturing method of the present invention, a magnetophoretic display device which is easy to dispose of, is friendly to the global environment, and can improve the contrast on the display surface can be manufactured very easily. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view of a magnetophoretic color display device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part corresponding to a unit cell of the magnetophoretic color display device.

FIG. 3 is a perspective view of a honeycomb structure as a partition member.

FIG. 4 is a fragmentary cross-sectional view showing the manufacturing process of the magnetophoretic color display device.

5A to 5C are plan views of a mask sheet used in a manufacturing process of the magnetophoretic color display device, and FIG. 5D is a schematic diagram showing a pattern obtained by dividing a display surface for each color. It is.

FIGS. 6A and 6B are schematic views showing a process of manufacturing a honeycomb structure.

FIGS. 7A to 7C are schematic diagrams showing evaluation criteria in the example of the present invention.

[Explanation of symbols]

 2 ... Magnetophoretic color display device 4 ... Top panel sheet 4a ... Display surface 6 ... Back panel sheet 8 ... Sealed space 10 ... Honeycomb structure (partition member) 12a-12c ... Dispersed liquid 14a-14c ... Colored magnetic particles 15 ... Cell space 16 Magnetic pen for recording (magnetic member for recording) 17 Magnet 18 Magnetic arm for erasing (magnetic member for erasing) 19 Magnet 20 Magnetic display panel 30 Cell 50a to 50c Mask sheet 52a to 52c Coloring opening

Continuation of the front page (72) Inventor Kenji Imamura 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References JP-A-9-71042 (JP, A) JP-A-10-44689 ( JP, A) JP-A-10-282908 (JP, A) JP-A-7-29146 (JP, A) JP-A-4-106581 (JP, A) JP-A-4-199087 (JP, A) JP Hei 4-199086 (JP, A) JP-A-2-193185 (JP, A) Registered utility model 3053706 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G09F 9/37 G02F 1/167

Claims (5)

(57) [Claims] 1. A transparent surface panel sheet made of polyethylene terephthalate, a back panel sheet arranged so as to form a sealed space between the surface panel, and a space between the surface panel sheet and the back panel sheet. A partition member for partitioning the sealed space having a thickness of 0.8 to 1.5 mm into a number of cells, and a dispersion liquid containing magnetic particles sealed inside each cell partitioned by the partition member. , Is movable along the outer surface of the top panel sheet,
While in contact with the outer surface of the top panel sheet,
The effective magnetic flux density on the outer surface of the back panel sheet is 100 to 5
Recording magnetic member having a magnetic force of about 00 Gauss
And a rear panel disposed on an outer surface of the rear panel sheet,
The front panel seal is placed on the outer surface of the
The effective magnetic flux density on the outer surface of the plate is 300 to 1500 Gau
a magnetic member for erasing having a magnetic force of about ss , wherein the average particle size of the magnetic particles is 50 to 200 μm, and the applied magnetic field to the magnetic particles is 500 ( O
e) The magnetization of the magnetic particles at the time of e) is 20.0 emu / g or more, and the dispersion liquid is a liquid in which colored magnetic particles are dispersed in a single color fluid, and the viscosity of the single color fluid is 25 ° In C, 200-
800 cp, wherein the single color fluid includes at least a dispersion medium and a single tone pigment, the total weight of the single color fluid is 100% by weight, and the weight% of the dispersion medium in the single color fluid is A. When the weight% of the single tone pigment in the single color fluid is B, the weight ratio A /
A magnetophoretic display device, wherein B has a relationship of 10 ≦ A / B ≦ 20. 2. The magnetophoretic type according to claim 1, wherein the single color fluid is a white fluid, the dispersion medium is isoparaffin, and the single color tone pigment is a mixture of a white tone inorganic oxide. Display device. 3. The first dispersion liquid containing first colored magnetic particles sealed in a specific cell selected from among cells divided by the partition member, wherein the first dispersion liquid contains: A second dispersion liquid containing second colored magnetic particles, which is enclosed in a selected specific cell among the cells in which the dispersion liquid is not enclosed, and is colored differently from the first colored magnetic particles; Claim 1.
Or the magnetophoretic display device according to 2. 4. The magnetophoretic display device according to claim 1, wherein the partition member is a member in which paper is covered with a resin. Wherein said erasing magnetic member, according to claim 1 which is disposed movably along the outer surface of the back panel sheet
5. The magnetophoretic display device according to any one of items 1 to 4 .