JP3430054B2 - Magnetophoretic color display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetophoretic color display device which causes a magnetic field to cause a plurality of types of colored magnetic particles enclosed in the display device to electrophoretically perform a certain color display.

[0002]

2. Description of the Related Art For example, JP-A-53-127032, JP-A-52-30196, and JP-A-55-25
The magnetophoretic monochrome display device shown in Japanese Patent No. 934 has been conventionally known. 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 dispersed liquid containing black magnetic particles and a white fluid is enclosed in each cell. .
By moving a recording magnetic member etc. in contact with the outer surface of the surface panel sheet, the black magnetic particles in the dispersion liquid encapsulated in the cell corresponding to the trajectory of the pen are moved by the magnetic field action of the pen. Magnetophoresis occurs from the bottom to the surface panel sheet side. As a result, some monochrome display is performed on the outer surface of the transparent front panel sheet due to the difference in contrast between the white fluid and the black magnetic particles.

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

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

[0005]

However, in the magnetophoretic color display device capable of displaying a color image,
In particular, regarding various conditions and other conditions that can eliminate display breaks at the boundary (boundary part) of each cell, have no color bleeding, have a clear color tone, and improve the resolution of color display images. Was not disclosed in the prior art.

The present invention has been made in view of the above situation, and in a magnetophoretic color display device capable of displaying a color image, in particular, a display break at a boundary portion (boundary portion) of each cell is eliminated, and a color display is eliminated. No bleeding, clear color tone,
An object of the present invention is to provide a magnetophoretic color display device capable of improving the resolution of a color display image.

[0007]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to achieve the above objects, and as a result, the thickness of a sealed space between a front panel sheet and a back panel sheet, various conditions of colored magnetic particles, Only by maintaining the mixing ratio of the colored magnetic particles and various conditions of the dispersion liquid in a predetermined relationship comprehensively, the display breakage at the boundary (boundary part) of each cell is eliminated and the color bleeding is eliminated. The inventors have found that the sharpness of color tone and the resolution of a color display image can be improved, and have completed the present invention.

That is, in the magnetophoretic color display device according to the present invention, a transparent front panel sheet, a back panel sheet arranged so that a sealed space is formed between the front panel and the front panel, It is provided between the panel sheet and the back panel sheet and has a thickness of 0.8 to 1.5 m.
a partition member for partitioning the sealed space of m into a large number of cells;
A first dispersion liquid containing first colored magnetic particles, which is enclosed in a selected specific cell among cells partitioned by the partition member, and a cell in which the first dispersion liquid is not enclosed A magnetophoretic color display device comprising at least a second dispersion liquid containing second colored magnetic particles encapsulated in a selected specific cell, the second colored magnetic particles being colored differently from the first colored magnetic particles. Therefore, the particle size of the first colored magnetic particles and the second colored magnetic particles is
Is 50 to 200 μm, and the magnetization of the magnetic particles is 2 when the applied magnetic field to the magnetic particles is 500 (Oe).
0.0 emu / g or more, the first dispersion liquid is a liquid in which the first colored magnetic particles are dispersed in a single color fluid, and the second dispersion liquid is a second color in the single color fluid. A liquid in which magnetic particles are dispersed, and the viscosity of the single color fluid is 200 to 800 cp at 25 ° C.,
The single color fluid is a dispersion medium (not limited to isoparaffin,
Other dispersion media) and a single-tone pigment (not limited to white-tone inorganic oxides, including other pigments, dyes, colorants, etc., not limited to white), at least
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 pigment in the single color fluid is B, the weight ratio is A /
B is Ri near relation 10 ≦ A / B ≦ 20, the white fluid
And the mixing ratio of the first and second colored magnetic particles is 8
10 to 20% by weight for 0 to 90% by weight of white fluid
Of the first and second colored magnetic particles .

In the present invention, the partition member is not particularly limited, but a honeycomb structure having a large number of cells of substantially regular hexagonal cylinder shape is preferable. Alternatively, it may be a microcapsule capable of enclosing the dispersion liquid.

[0010]

[0011]

As the single color fluid, there are first and second fluids.
A color having a high contrast with respect to the color of the colored magnetic particles is preferable, and it is not particularly limited, but a white fluid is preferable. It is also preferable that the white fluid contains at least isoparaffin and a mixture of a plurality of white-tone inorganic oxides.

[0013]

[0014]

The magnetophoretic color display device according to the present invention further comprises a recording magnetic member movable along the outer surface of the front panel sheet, and the recording magnetic member comprises the recording magnetic member. It is preferable to have a magnetic force such that the effective magnetic flux density on the outer surface of the back panel sheet becomes 100 to 500 Gauss in a state of being in contact with the outer surface of the front panel sheet.

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

Further, the magnetophoretic color display device according to the present invention further includes an erasing magnetic member arranged on the outer surface of the back panel sheet, and the erasing magnetic member includes the erasing magnetic member. When placed on the outer surface of the back panel sheet, it preferably has a magnetic force such that the effective magnetic flux density on the outer surface of the front panel sheet is 300 to 1500 Gauss.

It is preferable that the erasing magnetic member is movably arranged along the outer surface of the back panel sheet.

In the magnetophoretic color display device according to the present invention, in addition to the first dispersed liquid and the second dispersed liquid, a third coloring different from the first colored magnetic particles and the second colored magnetic particles is formed. A third dispersion liquid containing colored magnetic particles may be included. In this case, the colors of the first to third colored magnetic particles are different from each other, and preferably the three primary colors (red,
It is preferably either green or blue). Also,
The magnetophoretic color display device according to the present invention may have a dispersion liquid containing, in addition to these first to third colored magnetic particles, magnetic particles colored differently from them.

[0020]

In the present invention, the sealed space has a thickness of 0.8 to
1.5 mm, more preferably 1.00 to 1.40 mm
Is. If this thickness is too small, in order to adjust the monochromaticity (eg whiteness) of the monochromatic fluid for hiding the color tone of the colored magnetic particles in the cell, the monochromatic fine particles (eg white fine particles) in the monochromatic fluid are adjusted. ) Will need to be included in large quantities. As a result, the viscosity of the single color fluid becomes high, the magnetic migration of the colored 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. Also, the resolution and color tone of the color display object displayed on the display surface of the display device tend to be poor.

Further, if the thickness of the sealed space is too large, the magnetophoretic distance is long in order to cause the colored magnetic particles to sufficiently migrate to the surface panel sheet side in the cell. It is necessary to increase the magnetic flux density of the magnetic member. In addition, the cost of the magnet attached to the recording or erasing magnetic member is high. Also,
The resolution of the color display object displayed on the display surface of the display device also tends to be poor.

In the present invention, particles of the colored magnetic particles
The size is 50 to 200 μm, and more preferably 75 to
It is 150 μm. When the particle size of the colored magnetic particles is too small, the background color of a single color fluid (white fluid) is easily contaminated due to the influence of the colored magnetic particles, and the response of magnetophoresis at the time of erasing the image display is slow. Tends to become. Also,
If the particle size of the colored magnetic particles is too large, color display is possible, but resolution of color display tends to deteriorate.

The colored magnetic particles used in the present invention preferably have a magnetization of 20.0 emu when the magnetic field applied to the colored magnetic particles is 500 (Oe).
/ G or more, more preferably 22.0 emu / g or more. The colored magnetic particles are required to have a magnetization that causes magnetophoresis under the action of a low magnetic field possessed by the recording magnetic member or the erasing magnetic member. By having a magnetic susceptibility within the above range, the colored magnetic particles are subjected to magnetophoresis. Is sufficiently performed, and 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.
It is 0 cp, more preferably 300 to 600 cp.
If the viscosity of the single-color fluid (white fluid) is too low, the single-color (whiteness) of the single-color fluid (white fluid) becomes weaker, and when the image is erased (a single color is displayed on the display surface), the colored magnetic particles The 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) masks the color tone of the colored magnetic particles, and a clear color tone display cannot be obtained. The magnetic migration of the colored 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.

In the present invention, when the weight% of the dispersion medium in the single color fluid is A and the weight% of the single color pigment in the single color fluid is B, the weight ratio A / B is preferable. Has a relationship of 10 ≦ A / B ≦ 20.

[0026]

If the weight ratio A / B is too large, the white fluid (single color fluid) has a weak whiteness (single color), and the colored magnetic particles should be completely erased from the panel display surface when the displayed image is erased. And 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) masks the color tone of the colored magnetic particles, and a clear color tone display tends not to be obtained.

In a recording magnetic member that can be used in the magnetophoretic color display device of the present invention, the recording magnetic member is provided on the outer surface of the back panel sheet while being in contact with the outer surface of the front panel sheet. Effective magnetic flux density is 1
It is preferable to have a magnetic force of about 00 to 500 Gauss. Further, in the erasing magnetic member that can be used in the magnetophoretic color display device of the present invention, the erasing magnetic member is effective on the outer surface of the front panel sheet when the erasing magnetic member is arranged on the outer surface of the rear panel sheet. It is preferable to have a magnetic force such that the magnetic flux density is 300 to 1500 Gauss.

If the magnetic force of the recording magnetic member is too small, the magnetophoretic action in the cell is weak, and it is difficult to perform color display on the display surface. Further, if the magnetic force of the recording magnetic member is too large, the magnetic field is too strong, which tends to deteriorate the resolution of the color display object when the magnetophoresed colored magnetic 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 becomes difficult to pull back the colored magnetic particles from the panel display surface side, and the display object on the display surface is erased. Tends to be difficult. Further, if the magnetic force of the erasing magnetic member is too large, the magnetic field is too strong, and the colored magnetic particles that have been electrophoresed for erasing remain on the inner surface of the panel display surface as a spike phenomenon. There is a tendency that the display cannot be erased cleanly.

In the present invention, as described above, the thickness of the sealed space, the particle size of the colored 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 material. By limiting the effective magnetic flux density of the member in a specific area, a color display on the panel display surface can be clearly displayed and a magnetophoretic color display device capable of clear erasing can be obtained.

The application of the magnetophoretic color display device according to the present invention is not particularly limited, and it can be used for toys for children, teaching materials, calligraphy boards,
It can be widely used as a board for various games, a bulletin board for recording, a memo board, a blackboard, a whiteboard, an advertising board, a portable memo pad, and the like. The location where the magnetophoretic color display device according to the present invention is installed is not particularly limited, and is not limited to the inside of a building such as a factory or a school, and may be outdoors at a station platform, a ticket gate, a construction site, or underwater. May be.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a cross-sectional view of a magnetophoretic color display device according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of an essential 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 sectional view of an essential part showing a manufacturing process of the magnetophoretic color display device, and FIGS. 5A to 5C are planes of a mask sheet used in the manufacturing process of the magnetophoretic color display device. FIG. 6D is a schematic diagram showing a pattern in which the display surface is divided for each coloring, and FIGS. 6A to 6C are schematic diagrams showing evaluation criteria in the examples of the present invention.

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

The magnetic display panel 20 has a front panel sheet 4 and a rear panel sheet 6, and the outer peripheries of these sheets 4 and 6 are heat-sealed or adhered to each other so that the sheets 4 and 6 are A sealed space 8 is formed between them. A honeycomb structure 10 as a partition member is arranged in the closed space 8. As shown in FIG. 3, the honeycomb structure 10 has a large number of substantially regular hexagonal tubular 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 the first colored magnetic particles 14a, a dispersion liquid 12b containing the second colored magnetic particles 14b, And any of the third dispersion liquid 12c containing the third colored magnetic particles 14c is enclosed. Which of the dispersion liquids 12a to 12c is enclosed in any of the cell spaces 15 is arbitrary, but a large number of cell spaces 15 constituting the display surface are divided into, for example, three blocks by each method by a method described later. Different dispersion liquids 12a to 1 for each
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 magnetophoretic color display device 2, the tip of the magnetic pen 16 is slid on the display surface 4a, which is the surface of the front panel sheet 4, so that the display corresponding to the trajectory of the magnetic pen 16 is moved. Colored magnetic particles 14 in cell 30
The magnetic field acts on a to 14c to cause coloring magnetic particles 14a to 14c.
Magnetophoresis of c occurs inside the cell 30, and color display is performed on the display surface 4a. In order 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 and connected to the magnetic display panel 20 in advance. The operation of the magnetic lever 18 may be manually performed by an operator's hand, but it may also 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 are covered and protected by a synthetic resin casing or the like. The magnetic lever 18 is preferably movably connected to its casing. An opening is formed in the casing so that the display surface 4a of the magnetic display panel 20 is exposed.

The magnet 17 of the recording magnetic pen 16 has an effective magnetic flux density of 100 to 500 Gauss on the outer surface of the rear panel sheet 6 with the magnet 17 of the magnetic pen 16 in contact with the outer surface of the front panel sheet 4. Has a certain degree of magnetic force. Further, the magnet 19 of the erasing magnetic lever 18 has an effective magnetic flux density of 300 to 1500 Gauss on the outer surface of the front panel sheet 4 when the magnet 19 of the magnetic lever 18 is arranged on the outer surface of the rear panel sheet 6. Has a degree of magnetic force.

If the magnetic force of the magnet 17 of the recording magnetic pen 16 is too small, the color migration on the display surface 4a is difficult 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, so that the magnetically migrated colored magnetic particles 14 are formed.
When a to 14c are displayed on the panel display surface 4a, the resolution of the color display tends to deteriorate.

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 becomes difficult to pull back c, and it tends to be difficult to erase the 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, and thus the colored magnetic particles 1 that have been electrophoresed for erasing.
Since 4a to 14c remain on the inner surface of the panel display surface 4a as a spike phenomenon, the display on the panel display surface 4a tends not to be erased neatly.

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

In the display panel 20 of the display device 2 according to this embodiment, the front panel sheet 4 is made of a transparent sheet, and the outer surface thereof becomes the panel display surface 4a. The material of the surface panel sheet 4 is not particularly limited as long as it is transparent, but is preferably made of a synthetic resin having excellent durability such as vinyl chloride, polyethylene terephthalate, polyester and polyethylene. The thickness of the front panel sheet 4 is
Although not particularly limited, preferably 0.10 to 0.50 m
m, and more preferably 0.15 to 0.25 mm.
If the thickness of the surface panel sheet 4 is too small, the magnetic pen 1
The durability against friction of No. 6 tends to decrease, and if the thickness is too large, the material is wasted. The front panel sheet 4 may be a multi-layer sheet.

The back panel sheet 6 does not necessarily have to be transparent, and its material is not particularly limited,
For example, it is made of synthetic resin such as vinyl chloride, polyethylene terephthalate, polyester, polyethylene. The thickness of the back panel sheet 6 is not particularly limited, but is preferably 0.05 to 0.30 mm, more preferably 0.10 to 0.20 mm. If the thickness of the back panel sheet 6 is too small, the durability tends to decrease, and if the thickness is too large, the material is wasted. The back panel sheet 6 may also be a multi-layer sheet.

The honeycomb structure 10 shown in FIG. 3 is made of, for example, water resistant special paper or synthetic resin such as polyester, vinyl chloride or acrylic. The cross-sectional area of each cell space 15 in the honeycomb structure 10 having a substantially regular hexagonal shape is not particularly limited, but is preferably 1.0 to
5.0 mm ² , more preferably 2.0 to 3.0 mm
It is ² . The smaller the cross-sectional area, the finer the display becomes possible. However, if the cross-sectional area is too small, the 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 the display object on the display surface 4a and is excellent in strength.

The thickness of the partition wall that divides each cell space 15 of the honeycomb structure 10 is not particularly limited, but is preferably 0.01 to 0.5 mm, more preferably 0.03 to.
It is 0.1 mm. The partition wall thickness is preferably as thin as possible from the viewpoint of eliminating discontinuity of the 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, this thickness T is 0.8 to 1.5 mm. If this 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, the magnetophoresis of the colored magnetic particles 14a to 14c does not occur smoothly, and 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. In addition, the resolution and color tone of the display object displayed on the display surface 4a of the display device tend to be adversely affected.

If the sealed space T is too thick,
In order to cause the colored magnetic particles 14a to 14c to sufficiently migrate to the front panel sheet 4 side or the rear panel sheet 6 side in the cell 30, since the magnetophoretic distance is long, the magnet 17 in the magnetic pen 16 or the magnetic lever 18 is used. Or 19
It is necessary to increase the magnetic flux density of. Further, these magnets 17 or 19 also become expensive in cost.

As shown in FIG. 2, the dispersion liquids 12a to 12c enclosed in each cell 30 are contained in a white fluid.
It is a liquid 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
nO), white tone inorganic oxides such as silica (silicon oxide: SiO ₂ ) are preferably used. The dispersion medium is not particularly limited, and examples thereof include polar dispersion media such as water and glycols, and nonpolar dispersion media such as organic solvents and oils. In the present embodiment, paraffins are preferable. (Especially isoparaffin) is used.

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

When the weight ratio A / B is too large, the white fluid is weak in whiteness and the colored magnetic particles 1 are used when the displayed image is erased.
4a to 14c cannot be completely erased from the panel display surface 4a, and the panel display surface 4a tends to appear dirty. On the other hand, if A / B is too small, the white color of the white fluid masks the color tones of the colored magnetic particles 14a to 14c, and a clear color tone display cannot be obtained.

In this embodiment, the viscosity of this 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 colors of the colored magnetic particles 14a to 14c should be completely hidden from the display surface 4a when the image is erased (white is displayed on the display surface 4a). I can't. When the viscosity of the white fluid is too high, the white color of the white fluid masks the color tone of the colored magnetic particles 14a to 14c, so that a clear color tone display cannot be obtained, and the magnetic migration of the colored magnetic particles 14a to 14c is prevented. The magnetic pen 16 for recording and the magnetic lever 18 for erasing do not happen smoothly.
It is necessary to increase the magnetic flux density of the magnet 17 or 19 of FIG.

In the present embodiment, each of the dispersion liquids 12a-12
colored magnetic particles 14a contained together with a white fluid in c.
14c is not particularly limited as long as it is colored differently from each other, and various colored fine particles can be used. For example, as the colored magnetic particles 14a to 14c, fine particles in which the outer peripheral surface of a magnetic material such as ferrite powder or metal powder is coated 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 the following materials. The material of such a magnetic material is not particularly limited, and oxide magnetic materials such as black magnetite, chromium dioxide, ferrite (spill-type ferrite, magnetoplumbite-type ferrite), cobalt, iron, copper, nickel, or Metal magnetic materials such as these alloys are exemplified, but metal magnetic materials are preferable.

The colored magnetic particles 14a to 14c are required to have such a magnetization as to cause magnetophoresis under the action of the low magnetic field possessed by the recording magnetic pen 16 or the erasing magnetic lever 18, and the magnetic susceptibility within the above range is obtained. By having the colored magnetic particles 14a to 14c, the magnetophoresis is sufficiently performed, and the display and / or erasing action on the display surface 4a of the display device is improved.

As the synthetic resin contained in the colored magnetic particles 14a to 14c, a known resin may be used.
It may be selected from styrene type, polyester type, acrylic type, epoxy type and the like. As the colorant, a known inorganic or organic pigment corresponding to the color tone to be colored may be used. For example, colored magnetic particles 14a to 14c.
When any one of them 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 coloring agents are preferably used. That is, as the blue colorant, a colorant such as a Co—Mn-based complex oxide pigment is preferable. Moreover, as the green colorant, a colorant such as a Co—Mn-based composite oxide pigment is preferable. Further, as the red colorant, a colorant such as hematite is preferable.

The synthetic resin and / or the coloring agent in the colored magnetic particles 14a to 14c preferably form a coating layer for coating the magnetic powder. When the magnetic powder is not coated 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 the dispersion liquids 12a to 1c.
In 2c, the type of synthetic resin and / or colorant is
It is also possible to use a synthetic resin which is selected so that it does not soften or swell, and which is partially crosslinked with a crosslinking agent (for example, a urethane modifier).

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

In this embodiment, the colored magnetic particles 14a are used.
The particle size of ~ 14c is 50-200 µm. Such colored magnetic particles 14a to 14c may have a spherical shape or an irregular shape other than a spherical shape, and can be obtained by a conventional general manufacturing method. For example, the composition composed of the synthetic resin and / or the coloring agent and the magnetic material shown above is melt-mixed, and then pulverized and air-classified to 50 to 2
The colored magnetic particles 14a to 14c of 00 μm are obtained. Alternatively, a similar composition can be mixed in a solvent, dried and
Classified and colored magnetic particles 14a to 14 of 50 to 200 μm
get c. If the particle size of the colored magnetic particles is too small,
The white fluid, which is a background color, is likely to be contaminated due to the influence of the colored magnetic particles 14a to 14c, and the responsiveness of magnetophoresis at the time of erasing the image display tends to be slow. Further, if the particle size of the colored magnetic particles 14a to 14c is too large, although color display is possible, the resolution of color display tends to deteriorate.

In the present embodiment, the mixing ratio of the white fluid and the colored magnetic particles 14a to 14c in the dispersion liquids 12a to 12c sealed in each cell 30 is such that the colored magnetic particles 14 are mixed.
Although it depends on the color tone of a to 14c, it is generally 8
The weight ratio of the white fluid of 0 to 90% by weight and the colored magnetic particles 14a to 14c of 10 to 20% by weight is preferable. Colored magnetic particles 14a to 14c in dispersion liquid
When the content ratio of is too low, the colored magnetic particles 14a to 14c
Since the amount of light is small, 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 a break may occur. Further, if the content ratio of the colored magnetic particles 14a to 14c is too high, the concentration of the display matter on the display surface 4a of the display device can be increased, but it is easy to contaminate the white fluid. In this case, the white color becomes weak, and the color contrast tends to decrease.

In order to manufacture the magnetophoretic color display device 2 according to this embodiment, first, as shown in FIG. 4, the honeycomb structure 10 is provided in the recess 4b of the surface panel sheet 4 having the recess 4b on the inner surface side. To house. After that, each cell space 15
The dispersion liquid 12a, 12b or 12c containing the magnetic particles of any one of the first to third colored magnetic particles 14a to 14c is put into the inside of the container according to a predetermined rule or randomly. In order to separate them according to a predetermined rule, a method of using a mask sheet or mold in which a pattern opening for each predetermined coloring is formed, a method of using a masking tape, a method of applying screen printing, etc. are exemplified. In the embodiment, the mask sheet 50 shown in FIGS.
a to 50c are used.

Mask sheet 5 shown in FIGS. 5A to 5C.
0a to 50c each have a first coloring opening 52.
a, the second coloring opening 52b and the third coloring opening 5
2c is formed. These openings 52a to 52c are
The patterns do not overlap each other.

For example, the mask sheet 50a having the openings 52a formed therein is positioned and placed inside the front panel sheet 4 containing the honeycomb structure 10 shown in FIG. Next, the blocked plural cell space 1 located in the 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 on which another pattern of openings 52b is formed 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 plural cell spaces 15 located in the pattern corresponding to the opening 52b of the mask sheet 50b.

Next, the mask sheet 50b is removed, and the mask sheet 50c in which the opening 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 in the inside of the blocked plural 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 the mask sheet shown in FIG.
As shown in FIG. 5, the back panel sheet 6 having the inner surface coated with the adhesive 42 is pressure-bonded to the upper surface of the honeycomb structure 10 shown in the figure and the inner surface of the front panel sheet 4 on the outer peripheral side,
Then, a part 40 of the outer circumference is heat-sealed to completely seal the inside, and the magnetic display panel 20 shown in FIG. 1 is obtained. However, in FIG. 1 and FIG. 4, the magnetic display panel 20 is shown upside down.

By this method, as shown in FIG. 5D, the entire display surface 4a is divided into three blocks having a predetermined pattern, and different color tones are provided inside the cell space 15 located in each block. Colored magnetic particles 14a-14c
It is possible to manufacture a magnetophoretic color display device 2 in which a plurality of colors can be displayed, in which the dispersion liquids 12a to 12c containing are arranged.

The present invention is not limited to the above-mentioned 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, and microcapsules or other partition members may be used. 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 means such as a string without being completely separated. Further, the recording magnetic member as the recording magnetic pen 16 can be automatically moved by an XY plotter or the like without being manually moved.

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

[0072]

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

Preparation of Encapsulated Material in Panel After isoparaffin, titanium oxide, zinc oxide, silicon oxide and alumina were quantitatively determined in the composition shown in Table 1 below, the mixture was 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 A is the weight% of isoparaffin in the white fluid, and B is the weight% of the white oxide mixture consisting of titanium oxide, zinc oxide, silicon oxide and alumina.
The ratio of / B is shown in Table 1. Table 1 shows the viscosities of the white fluids (white fluids) 1 to 7 at a temperature of 25 ° C. The viscosity was determined by using a B type viscometer (manufactured by Tokyo Keiki Co., Ltd.) and setting 500 cc of each white fluid.

[0074]

[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 were used. Got ready.

[0076]

[Table 2]

In Table 2, the black magnetic powder 1 is a magnetic material obtained by coating 70% by weight of a magnetic material containing Fe as a main component with 30% by weight of a coloring agent made of carbon and a synthetic resin made of styrene-acrylic resin. A particle and its particle size
And the magnetization characteristics are shown in Table 2.

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

The red magnetic powder 3 is magnetic substance particles obtained by coating 85% by weight of a magnetic substance containing Fe as a main component with 15% by weight of a coloring agent made of hematite and a synthetic resin made of styrene-acrylic resin. The particle size and magnetizing properties are shown in Table 2.

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

[0081] black magnetic powder 5, a magnetic material mainly composed of 60 wt% of Fe, a magnetic particles coated with a synthetic resin consisting of colorant and a polyester resin consisting of 40 wt% of carbon, the particles The size and magnetizing properties are shown in Table 2.

The black magnetic powder 6 is a magnetic material particle in which 75% by weight of a magnetic material containing Fe as a main component is coated with 25% by weight of a coloring agent made of carbon and a synthetic resin made of styrene-acrylic resin, The particle size and magnetizing properties are shown in Table 2.

[0083] red magnetic powder 7, a magnetic body made of 65 wt% of magnetite, a magnetic particles coated with a synthetic resin consisting of colorant and a polyester resin consisting of 35 wt% of hematite, its particle size and magnetization The properties are shown in Table 2. The average particle size of the colored magnetic powders 1 to 7 was measured by placing the colored magnetic powders on each sieve of mesh numbers # 83 to # 325 and vibrating them to obtain the amount of the colored magnetic powders remaining on each sieve. It was performed by calculating the average particle diameter from the ratio.

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

[0085]

[Table 3]

Production of Magnetic Display Panel The surface panel sheet 4 shown in FIG. 1 has a thickness of 0.20 m.
m, a transparent vinyl chloride sheet having a thickness of 0.10 mm is prepared as the back panel sheet 6, and the honeycomb structure 10 shown in FIG.
A honeycomb structure made of special paper was prepared. Honeycomb structure 1
The cross-sectional area of each cell space 15 at 0 is 3.0 mm
² and the thickness of the partition wall that partitions each cell space 15 is
It was 0.05 mm. 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 surface of the honeycomb structure 10 is adhered to the inner surface of the front panel sheet 4 by using an epoxy adhesive, the material enclosed in the panel is placed inside each cell space 15. Each of the inclusions obtained in the manufacturing process was filled with stirring. When filling the inclusions, in each of the panel samples 1 to 15 shown in Table 3, two or more kinds of colored magnetic powders are enclosed in the same panel sample so that multi-color display of two or more colors is possible. did. When encapsulating, use a masking tape to divide the display surface into predetermined blocks,
A white fluid containing different colored magnetic powder was enclosed in each block.

Then, as shown in FIG. 4, the rear panel sheet 6 made of a vinyl chloride sheet coated with an epoxy 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. By heat-sealing the outer peripheral portion 40, the inside was completely sealed, and panel samples 1 to 15 shown in Table 3 (corresponding to the magnetic display panel 20 shown in FIG. 1) were obtained.

The following measurements and evaluations were performed on the obtained magnetic panels 1 to 15. The results are shown in Table 4 below. The measurement was performed as follows.

Measurement a. To measure the magnetization of the colored magnetic powder sample, use a vibrating sample magnetometer (product number VSM-3 manufactured by Toei Industry Co., Ltd.), set the colored magnetic powder sample in a holder, and apply a magnetic field of 5
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 magnetic pen for recording in the magnetic display panel was performed by using the magnetic display panels 1 to 15 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 by a handy type magnetometer (product number FS-5 type manufactured by ADS Co., Ltd.). . Similarly, as shown in Table 3, the effective magnetic flux density of the magnet used for the erasing magnetic arm was measured by using the magnetic display panels 1 to 15 having a predetermined sealed space thickness and erasing 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 by applying a magnet for handy type magnetometer (Product No. F manufactured by ADS Co., Ltd.)
S-5 type).

C. Measurement of reflectance The reflectance on the display surface of the magnetic display panel is measured by a reflectance meter (product number REFLECTMETER manufactured by Tokyo Denshoku Co., Ltd.
/ TC-6MC type) was used to directly measure the display image on the display surface of the magnetic display panel with a reflectometer. The reflectance was calculated when white was displayed on the display surface of the magnetic display panel (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. In order to improve the color contrast on the display surface, the reflectance for white display is preferably 55% or more. The results are shown in Table 4 below.
Shown in.

D. Resolution of display object The resolution of the display object on the display surface was visually confirmed. The way of blurring the characters shown in FIG. 6A 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 after 10 repeated tests, and × indicates 5 times in 10 repeated tests. As described above, it is shown that blurring of characters is observed.

E. Discontinuity of the display object at the boundary part (boundary part) of each cell Boundary part (boundary part) of each cell on the magnetic display panel
The discontinuity of the display object in (3) was visually confirmed. In the evaluation of the break at the boundary of each cell in Table 4 below,
◯ indicates that no discontinuity was observed at the boundary of each cell as shown in FIG. 6 (C) even after 10 repeated tests, and × indicates 5 or more times in 10 repeated tests. , Shows that discontinuity was observed at the boundary of each cell shown in FIG. 6 (B).

F. Clarity of multiple colors when displayed on panel display surface Clarity of multiple colors when displayed on panel display surface was visually confirmed. The vividness of the color tone and the bleeding of the color were observed.

In the evaluation of 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 repeated tests, and x indicates
It shows that unclear color tone or bleeding of color was observed 5 times or more in 10 repeated tests.

[0097]

[Table 4]

As can be understood from all the above-mentioned tables, a magnetophoretic type using colored magnetic particles, a white fluid, a magnetic display panel, a recording magnetic member or an erasing magnetic member which is out of the preferable numerical range of the present invention. Compared to a color display device, colored magnetic particles within the preferred numerical range of the present invention, white fluid,
A magnetophoretic color display device that uses a magnetic display panel, a recording magnetic member, and an erasing magnetic member eliminates display breaks at the boundary (boundary portion) of each cell, has no color bleeding, and has a clear color tone. The resolution of the color display image can be improved.

[0099]

As described above, according to the present invention, it is possible to eliminate display breaks at the boundary (boundary part) of each cell, to prevent color bleeding, to provide a clear color tone, and to solve a color display image. It is possible to provide a magnetophoretic color display device capable of improving the image quality.

[Brief description of 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 an essential part corresponding to a unit cell of a magnetophoretic color display device.

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

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

5A to 5C are plan views of a mask sheet used in the manufacturing process of the magnetophoretic color display device, and FIG. 5D is a schematic view showing a pattern in which the display surface is divided for each coloring. Is.

6 (A) to 6 (C) are schematic diagrams showing evaluation criteria in Examples of the present invention.

[Explanation of symbols]

2 ... Magnetophoretic color display 4 ... Front panel sheet 4a ... Display surface 6 ... Rear panel sheet 8 ... Sealed space 10 ... Honeycomb structure (partitioning member) 12a to 12c ... Dispersed liquid 14a to 14c ... Colored magnetic particles 15 ... Cell space 16 ... Magnetic pen for recording (magnetic member for recording) 17 ... Magnet 18 ... Erase magnetic arm (erase magnetic member) 19 ... Magnet 20 ... Magnetic display panel 30 ... cell 50a-50c ... Mask sheet 52a to 52c ... Coloring openings

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Imamura 1-13-1 Nihonbashi, Chuo-ku, Tokyo, TDK Corporation (56) References JP-A-10-197908 (JP, A) JP-A-10 -171381 (JP, A) JPB 59-31710 (JP, B2) Registered utility model 3047170 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G09F 9/37

Claims (2)

(57) [Claims] 1. A transparent front panel sheet, a back panel sheet arranged so that a sealed space is formed between the front panel sheet and the front panel sheet, and the back panel sheet between the front panel sheet and the back panel sheet, A partition member that partitions the sealed space having a thickness of 0.8 to 1.5 mm into a large number of cells, and a first colored magnetic material that is sealed inside a specific cell selected from the cells partitioned by the partition member. A first dispersion liquid containing particles, and the first dispersion liquid is encapsulated inside a specific cell selected from cells not encapsulated, and is colored differently from the first colored magnetic particles. A second dispersion liquid containing second colored magnetic particles; and a recording magnetic member movable along the outer surface of the front panel sheet, the recording magnetic member being in contact with the outer surface of the front panel sheet. State, the effective magnetic flux density at the outer surface of the back panel sheet 100~500Gaus
a recording magnetic member having a magnetic force of about s, and an erasing magnetic member arranged on the outer surface of the rear panel sheet, the erasing magnetic member being arranged on the outer surface of the rear panel sheet. A erasing magnetic member having a magnetic force such that the effective magnetic flux density on the outer surface of the surface panel sheet is 300 to 1500 Gauss. particle support of the second colored magnetic particles
Is 50 to 200 μm, and the magnetization of the magnetic particles when the applied magnetic field to the magnetic particles is 500 (Oe) is 20.0 emu / g or more. 1 is a liquid in which the colored magnetic particles are dispersed, the second dispersed liquid is a liquid in which the second colored magnetic particles are dispersed in the white fluid, and the viscosity of the white fluid is 200 at 25 ° C. ~ 8
00 cp, the white fluid contains at least isoparaffin and a mixture of white-tone inorganic oxides, the total weight of the white fluid is 100% by weight, the weight% of isoparaffin in the white fluid is A, When the weight% of the mixture of the white-tone inorganic oxides in the white fluid is B, the weight ratio A / B has a relationship of 10 ≦ A / B ≦ 20.
The white fluid and the first and second colored magnetic particles.
The total ratio is 10 to 10% by weight of the white fluid.
A magnetophoretic color display device characterized by comprising ˜20% by weight of the first and second colored magnetic particles . 2. The erasing magnetic member is movably arranged along the outer surface of the back panel sheet.
The magnetophoretic color display device described in 1.