JPH11149265A - Magneto-phoretic display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-phoretic display panel using magnetic particles of good responsiveness to magnetic force, good coloring property, without impairing the color of a coloring agent, by enclosing the display panel with magnetic particles, a dispersion medium, the coloring agent constituting a background part, and by request a dispersion fluid made of a thickening agent. SOLUTION: Opposed two non-magnetic panels 12a, 12b are provided, and the panel 12a is on the visual side, the panel 12b is on the non-visual side. Many partition walls 14 are provided between these panels 12a, 12b, and many honeycomb type cells 16 are formed by these partion walls 14 and the panels 12a, 12b. The interior of the cell 16 is enclosed with magnetic particles 18, a dispersion medium, a coloring agent constituting a background part, and by request a dispersion fluid 20 made of a thickening agent. By using deformed stainless steel particles coloring the surface as the magnetic particles 18, clear color display can be performed, and because the magnetic particle 18 is deformed, responsiveness to a magnet can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetophoretic display panel.

[0002]

2. Description of the Related Art Conventionally, a multi-cell structure is formed between two substrates (panels). In these cells, magnetic particles such as magnetite and ferrite, a dispersion medium, and a colorant constituting a background are formed. There is known a magnetophoretic display panel in which a dispersion fluid comprising a thickener, if desired, is enclosed.

[0003] In this magnetophoretic display panel, when a front surface of a substrate is traced with a magnetic pen, magnetic particles attracted by the magnetic force of the magnetic pen migrate from the back substrate to reach the front substrate, and the dispersion fluid is dispersed. Black and white display is formed by the difference in contrast between the magnetic particles and the magnetic particles.

FIG. 1 shows a part of a conventional magnetophoretic display panel 10. (A) is a sectional view, and (b) is a plan view. As shown in the figure, the magnetophoretic display panel 10 has two opposing non-magnetic panels 12a and 12b, and the panel 12a is on the viewing side and the panel 12b is on the non-viewing side. These panels 12
a, a large number of partitions 14 are provided between 12b,
A large number of honeycomb cells 16 are formed by the partition walls 14 and the panels 12a and 12b. Usually, the panel 12a has a thickness of 0.2 to 0.3 mm, the height of the partition wall 14 is 0.5 to 1.5 mm, the panel 12b has a thickness of 0.1 mm, and the maximum width of the cell 16 is about 4 mm.

[0005] Inside the cell 16, magnetic particles 18 are provided.
A dispersion fluid 20 comprising a dispersion medium, a colorant constituting a background portion, and a thickener, if desired, is enclosed. When the surface of the panel 12a on the viewing side is traced with a magnetic pen 22,
The magnetic particles 18 are sucked and migrated to reach the rear surface of the panel 12a, and characters and the like traced by the magnetic pen 22 are displayed on the surface of the panel 12a by the color difference between the colorant and the magnetic particles constituting the background. Generally, since the magnetic particles 18 have a ground color of black or dark brown, the colorant constituting the background is made white to perform black-and-white display.

Next, in order to erase the once displayed characters and the like, the erasing magnet 24 disposed on the back surface of the non-viewing side panel 12b is slid along the surface of the panel 12b. Then, the magnetic particles 18 attracted to the back surface of the panel 12a migrate to the panel 12b this time, and when viewed from the panel 12a side, only the color of the dispersion fluid 20 is seen, and the display of characters and the like is erased. It was done. The panel 12a uses an opaque, for example, white light diffusing plate so that the color of the magnetic particles 18 cannot be seen through from the viewing side when there is no display.

In recent years, there has been an increasing demand for color display in addition to the above black-and-white display. Some have done it.

[0008]

However, when the above magnetic particles are used, since these magnetic materials are black to dark brown, they are suitable for obtaining a black-and-white display. Is impaired, which is not suitable for color display. In general, since spherical magnetic particles are used, the coloring properties are not sufficient, the coloring agent is easily peeled off, and the response to magnetic force is not always sufficient. Furthermore, if the black and white display as described above is used to make the infant memorize letters and numbers, etc., the infant who is tired easily moves to another play, is very inefficient, and lacks attractiveness to attract the infant. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetophoretic display panel using magnetic particles which have good responsiveness to magnetic force, good coloring properties, and do not impair the color of a colorant.

[0010]

In order to solve the above-mentioned problems, the present invention employs the following means. 2. The magnetophoretic display panel according to claim 1, wherein a multi-cell structure is formed between the two substrates, and in these cells, magnetic particles composed of irregularly shaped stainless steel particles whose surface is colored and a dispersion medium are provided. And a dispersion fluid comprising a colorant constituting a background portion and, if desired, a thickener.

The magnetophoretic display panel according to claim 2 is
According to the first aspect of the present invention, the multi-cell structure is a honeycomb type.

According to a third aspect of the present invention, there is provided a magnetophoretic display panel.
The invention according to claim 1 is characterized in that the multi-cell structure is a microcapsule type.

[0013]

With the configuration described above, the responsiveness of the magnetophoretic display panel to the magnetic pen is improved. This can be attributed to the large surface area of the deformed magnetic particles. In addition, since the magnetic particles are irregularly shaped, the coloring properties of the color paint are good, and the peeling of the paint upon use is small, so that there is an advantage that deterioration with time is small, and stainless steel particles with a thin ground color are used. Therefore, the original color of the color paint can be visually recognized as compared with ferrite or magnetite, and a vivid color display can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The same or equivalent members as those described in the section of the related art will be described with the same reference numerals.

The appearance of the magnetophoretic display panel 10 according to the present invention is the same as that of the conventional one shown in FIG. 1 and will be described with reference to FIG. As shown in the figure, this magnetophoretic display panel 10 also has two non-magnetic panels 12a and 12b facing each other as in the conventional one, and the panel 12a
Is the viewing side and panel 12b is the non-viewing side. A large number of partitions 14 are provided between the panels 12a and 12b, and a large number of honeycomb cells 16 are formed by the partitions 14 and the panels 12a and 12b.

Inside the cell 16, a dispersion fluid 20 comprising magnetic particles 18, a dispersion medium, a colorant constituting a background portion and, if desired, a thickener is sealed. When the surface of the panel 12a is traced by the magnetic pen 22, the magnetic particles 18 are attracted and migrate to reach the back surface of the panel 12a, and the color difference between the colorant for displaying the background and the magnetic particles 18 causes the magnetic pen 18 to be applied to the surface of the panel 12a. The character traced in step 22 is displayed.

Next, the magnetic particles 18 used here are used.
Will be described. The magnetic particles 18 are stainless steel particles, whose components are: carbon C... 0.03% or less, silicon Si... 1.5% or less, manganese Mn... 0.3% or less, phosphorus P: 0.04% or less Sulfur S: 0.03% or less Nickel Ni: 0.6% or less Chromium Cr: 11.5 to 13.5% Iron Fe ... remaining

As shown in the sectional view of FIG.
It is odd. Here, the irregular shape means that the shape of the particles is not unified to a specific shape such as a sphere or a substantially rectangular parallelepiped, and each particle has a different shape.
Further, it is preferable that the surface is formed with a complicated uneven surface.

The particle size is measured on the long diameter side,
It is distributed in the range of 30 to 100 μm, and the average particle size is 7
It is 0 to 75 μm.

The magnetic particles 18 are made of stainless steel composed of the above-mentioned components, but are manufactured by a water atomizing method in order to make the particles irregular. In addition, the water atomizing method is a method of injecting high-pressure water into molten steel to powderize the steel. Due to the wide range of size distribution of the particles produced by this method, the above ranges are determined by sieving and excluding other parts.

Next, the color coloring of the magnetic particles 18 will be described. An acrylic resin paint is used as the paint. Polyurethane, epoxy or vinyl chloride may be used, but acrylic is superior in that it is less likely to peel off, and has good gloss and good water and oil resistance.

Next, the pigment to be mixed into the paint will be described. The pigment was implemented for four colors of blue, yellow, green and red. Blue pigment: Melamine / toluenesulfonamide resin fine particles colored with a fluorescent dye, with good solvent resistance and clear color. Yellow pigment: Inorganic pigment mainly composed of chrome yellow (PbCrO4) and chromium zinc, having high coloring power and hiding power. Green pigment: Chromium oxide (Cr2O3), an inorganic pigment with high stability to chemicals. Red pigment: azo organic pigment. In addition, acetone and toluene were used as a solvent.

The coloring of the magnetic particles 18 is performed by a spray dryer method, the drying temperature is 130 ± 2 ° C., and the drying time is 3 seconds. No pre-processing was performed. Thus, a colored film having a thickness of 20 to 30 μm was formed on the surface of the magnetic particles 18. Instead of the pigment, pigments and dyes such as ultramarine blue, aniline blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, and phthalocyanine green can be used.

The magnetic particles 18 produced as described above
Since the material is stainless steel, the saturation magnetization is lower by about 10% than that of ferrite or the like. This can be dealt with by increasing the magnetic force of the magnetic pen by 20%. Since the stainless steel is used, the color of the colorant can be displayed without deteriorating the original color without having a light ground color and not being covered with a silver-white concealing film or the like. In addition, since the magnetic particles 18 are irregularly shaped, they have a better magnetic sensitivity than a spherical shape, a good adhesion of the paint, and are hardly rusted. is there.

Further, by coloring the magnetic particles 18 as described above, the heat resistance can be improved.
At a temperature of ° C., the magnetic particles solidify in a dumpling shape, whereas in the case of the magnetic particles 18 in this embodiment, such a phenomenon is not observed.

Next, a second embodiment of the present invention will be described.
This will be described with reference to the drawings. The same or equivalent members as those described in the first embodiment are denoted by the same reference numerals.

As shown in FIG. 3, the magnetophoretic display panel 30 according to the second embodiment has two non-magnetic panels 12a and 12b facing each other. The non-visual side. These panels 12
A large number of spherical microcapsules 26 are accommodated between a and 12b, and the microcapsules 26 form a multi-cell structure. Inside the microcapsules 26, the honeycomb-type cells 16 in the first embodiment are provided.
A dispersion fluid 20 composed of the same magnetic particles 18 made of colored stainless steel, a dispersion medium, a colorant constituting a background portion, and, if desired, a thickener, is contained therein. It is enclosed.

The microcapsules 26 are made of the magnetic particles 18.
A dispersion fluid 20 comprising a dispersion medium, a colorant constituting a background portion, and, if desired, a thickener;
It is composed of a shell material such as a polymer covering the shell. The resin used as the shell material generally includes an acrylic resin, a methacrylic resin, a polystyrene resin, a polyester resin, a polyurethane resin, a polyamide resin, an epoxy resin, and the like. Alternatively, they are used in combination.

The method for producing the microcapsules 26 includes a phase separation method in which a dense layer of polymer is separated around a dispersion fluid 20 serving as a core material dispersed in a polymer solution, and a method of forming a polymer around a core material in a polymer solution. In-liquid curing coating method in which the polymer is cured with a curing test agent, etc., in-situ weight covering the surface of the core material with polymer by supplying a monomer or polymerization catalyst from either the inner or outer phase of the emulsion in which the core material is dispersed There is a law. In particular, phase separation methods,
According to the in-situ polymerization method, the particle size is uniform, and the magnetic particles 1
The microcapsules 26 that can easily move the microcapsules 8 can be manufactured.

When the surface of the panel 12a on the visual side of the thus formed magnetophoretic display panel 30 is traced with the magnetic pen 22, the magnetic particles 18 are attracted and the microcapsules 2 are drawn.
6, the microcapsules 26 on the panel 12a side
Colorant and magnetic particles 1 reaching back and displaying background
The characters and the like traced with the magnetic pen 22 are displayed on the surface of the panel 12a in a color difference from the color 8. The panel 12a uses an opaque, for example, white light diffusing plate so that the color of the magnetic particles 18 cannot be seen through from the viewing side when there is no display.

Next, in order to erase the characters and the like once displayed, the erasing magnet 24 arranged on the back of the non-visual side panel 12b is slid along the surface of the panel 12b. Then, the magnetic particles 18 attracted to the back surface of the microcapsules 26 on the panel 12a side migrate inside the microcapsules 26 in the direction of the panel 12b, reach the back surface of the microcapsules 26 on the panel 12b side, and When viewed from the side, only the color of the dispersion fluid 20 is visible, and the display of characters and the like has been deleted.

Next, FIG. 4 is a plan view showing the appearance when the present invention is applied to the color drawing toy 1 for an infant. This infant color drawing toy 1 has a frame 2 made of a substantially rectangular plastic material, and a magnetophoretic display panel 10 is fitted into the center of the frame 2. A slit 3 is provided in the horizontal direction below the frame 2, and a bar-shaped permanent magnet 24 slidably formed using the slit 3 is arranged. A handle 24a for sliding the permanent magnet 24 is disposed on the front side of the frame 2, and the rod-shaped (ruled) permanent magnet 24 is close to the back surface of the magnetophoretic display panel 10 while being connected to the handle 24a. When the handle 24a is slid left and right, the permanent magnet 24
Slides on the back surface of the magnetophoretic display panel 10.

The shape of the magnetophoretic display panel 10 and the cell 1
6, the internal structure or the material and shape of the magnetic particles to be used;
The size, coloring mode, manufacturing method, etc. are the same as those shown in FIG. The cell 16 is divided into desired regions in advance, and a dispersion fluid containing magnetic particles colored in different colors for each region is sealed therein. This will be described later. Note that the different color is a concept that includes the same color having different shades and also includes black. Therefore, the panel 1 on the viewing side
When the surface of 2a is traced with the magnetic pen 22, the magnetic particles 18 are sucked and migrated to reach the rear surface of the panel 12a, and the panel 12 is moved by the color difference between the colorant for displaying the background and the magnetic particles 18.
Characters and the like traced by the magnetic pen 22 are displayed on the surface a.

Next, in order to erase the characters and the like once displayed, the erasing magnet 24 arranged on the back side of the panel 12b on the non-viewing side is slid along the surface of the panel 12b. Then, the magnetic particles 18 attracted to the back surface of the panel 12a migrate to the panel 12b this time, and when viewed from the panel 12a side, only the color of the dispersion fluid 20 is seen, and the display of characters and the like is erased. It was done.

Next, the blue color produced as described above,
The method of enclosing the magnetic particles 18 colored red, green and yellow in the cells is as follows. First, as shown in FIG. 4, a large number of cells 16 formed between the panels 12a and 12b are formed in a desired area as shown in FIG. 4 (4a, 4b, 4c, 4d,...), And magnetic particles 18 of different colors of blue, red, green, and yellow are sealed in each of the divided areas.

For example, the dispersion fluid 20 containing the magnetic particles 18 colored red is sealed in the region 4a, the dispersion fluid 20 containing the magnetic particles 18 colored blue is sealed in the region 4b, and the dispersion fluid 20 is sealed in the region 4c. Is filled with the dispersion fluid 20 containing the magnetic particles 18 colored green, and the region 4d is filled with the dispersion fluid 20 containing the magnetic particles 18 colored yellow. The region is filled with a dispersion fluid in which only one color magnetic particle 18 is mixed. The number of cells 16 constituting the region is appropriately determined in a range of about 1 to 200, and it is preferable that the shapes of the regions are different from each other.

As described above, the large number of cells 16 formed between the panels 12a and 12b are previously stored in the desired area 4 (4a, 4a).
b, 4c, 4d,...), and magnetic particles 18 of colors different from blue, red, green, and yellow are enclosed in each of the divided areas, so that the tip of the pen tip is placed on the surface of the viewing side panel 12a. When a single straight line is drawn with a normal magnetic pen 22 having a magnet part diameter of 1 to 1.3 mm, a line having a width of about 2 mm can be drawn. With this alone, each time the area changes along the locus, blue, red, green Then, the magnetic particles 18 colored differently from yellow are attracted, and a colorful display is obtained as shown in FIG.

Naturally, the same applies to characters and pictures. FIG. 6 shows a state in which a picture of a UFO is displayed by contacting a hiragana “ma” with a magnetic stamp using a magnetic pen 22. As mentioned above, this color toy for toddlers has characters,
Numbers, symbols, etc. are displayed in multicolored colors, so that the infant can be encouraged to study and the area is usually not visible, so the result is unexpected for the infant So you won't get bored.
That is, it can be used as an educational toy. Further, since it is easy to display multi-colors, it is an educational toy suitable for infants who have begun to recognize colors and who are interested in colors, and can develop their color sense and aesthetic talent.

In the above embodiment, blue, red, green, and yellow are used as the colors. However, black and other colors can be used as a matter of course. Gray, crimson and pink are used as different colors.

The mode of forming the region for enclosing the magnetic particles colored in different colors is not limited to the example shown in FIG. For example, as shown in FIGS. 7 (a) and 7 (b),
A vertical (or horizontal) stripe or a diagonal stripe may be formed by each of the regions 28a, 28b, 28c,..., Or as shown in FIG. 28c... May be formed so as to be divided into a plurality of screens.

[0041]

As described above, according to the present invention,
A magnetophoretic display in which a multi-cell structure is formed between two substrates, and a dispersion fluid comprising magnetic particles, a dispersion medium, a colorant constituting a background portion, and, if desired, a thickener is sealed in these cells. In the panel, as the magnetic particles, the deformed stainless steel particles whose surface was colored were used,
Compared with ferrite or magnetite, the ground color is lighter and the original color of the color paint can be visually recognized, and a vivid color display can be performed. Further, since the magnetic particles are irregular in shape, the responsiveness to the magnet is good, the adhesion of the color coating is good, and the coating is hardly rusted.

[Brief description of the drawings]

FIG. 1 shows a part of a magnetophoretic display panel which has been conventionally used and is also a first embodiment of the present invention, wherein (a) is a cross-sectional view and (b) is a plan view.

FIG. 2 is a cross-sectional view of a magnetic colored irregular shaped magnetic particle.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a first illustration of a color drawing toy for an infant according to the present invention.
It is a top view of an embodiment.

FIG. 5 is a diagram in which one line is drawn with a magnetic pen.

FIG. 6 is a diagram showing a state in which a hiragana “ma” is stamped with a magnetic pen and a UFO picture is stamped with a magnetic stamp.

FIGS. 7 (a), (b) and (c) are plan views of a second embodiment of a color drawing toy for infants, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnetophoretic display panel 12a Viewing side panel 12b Non-viewing side panel 14 Partition wall 16 Cell 18 Magnetic particle 20 Dispersion fluid 22 Magnetic pen 24 Permanent magnet 26 Microcapsule 30 Magnetophoretic display panel

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[Procedure amendment]

[Submission date] April 16, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Magnetophoretic display panel

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetophoretic display panel.

[0002]

2. Description of the Related Art Conventionally, a multi-cell structure is formed between two substrates (panels). In these cells, magnetic particles such as magnetite and ferrite, a dispersion medium, and a colorant constituting a background are formed. There is known a magnetophoretic display panel in which a dispersion fluid comprising a thickener, if desired, is enclosed.

[0003] In this magnetophoretic display panel, when a front surface of a substrate is traced with a magnetic pen, magnetic particles attracted by the magnetic force of the magnetic pen migrate from the back substrate to reach the front substrate, and the dispersion fluid is dispersed. Black and white display is formed by the difference in contrast between the magnetic particles and the magnetic particles.

FIG. 1 shows a part of a conventional magnetophoretic display panel 10. (A) is a sectional view, and (b) is a plan view. As shown in the figure, the magnetophoretic display panel 10 has two opposing non-magnetic panels 12a and 12b, and the panel 12a is on the viewing side and the panel 12b is on the non-viewing side. These panels 12
a, a large number of partitions 14 are provided between 12b,
A large number of honeycomb cells 16 are formed by the partition walls 14 and the panels 12a and 12b. Usually, the panel 12a has a thickness of 0.2 to 0.3 mm, the height of the partition wall 14 is 0.5 to 1.5 mm, the panel 12b has a thickness of 0.1 mm, and the maximum width of the cell 16 is about 4 mm.

[0005] Inside the cell 16, magnetic particles 18 are provided.
A dispersion fluid 20 comprising a dispersion medium, a colorant constituting a background portion, and a thickener, if desired, is enclosed. When the surface of the panel 12a on the viewing side is traced with a magnetic pen 22,
The magnetic particles 18 are sucked and migrated to reach the rear surface of the panel 12a, and characters and the like traced by the magnetic pen 22 are displayed on the surface of the panel 12a by the color difference between the colorant and the magnetic particles constituting the background. Generally, since the magnetic particles 18 have a ground color of black or dark brown, the colorant constituting the background is made white to perform black-and-white display.

Next, in order to erase the once displayed characters and the like, the erasing magnet 24 disposed on the back surface of the non-viewing side panel 12b is slid along the surface of the panel 12b. Then, the magnetic particles 18 attracted to the back surface of the panel 12a migrate to the panel 12b this time, and when viewed from the panel 12a side, only the color of the dispersion fluid 20 is seen, and the display of characters and the like is erased. It was done. The panel 12a uses an opaque, for example, white light diffusing plate so that the color of the magnetic particles 18 cannot be seen through from the viewing side when there is no display.

In recent years, there has been an increasing demand for color display in addition to the above black-and-white display. Some have done it.

[0008]

However, when the above magnetic particles are used, since these magnetic materials are black to dark brown, they are suitable for obtaining a black-and-white display. Is impaired, which is not suitable for color display. In general, since spherical magnetic particles are used, the coloring properties are not sufficient, the coloring agent is easily peeled off, and the response to magnetic force is not always sufficient.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetophoretic display panel using magnetic particles which have good responsiveness to magnetic force, good coloring properties, and do not impair the color of a colorant.

[0010]

In order to solve the above-mentioned problems, the present invention employs the following means. 2. The magnetophoretic display panel according to claim 1, wherein a multi-cell structure is formed between the two substrates, and in these cells, magnetic particles composed of irregularly shaped stainless steel particles whose surface is colored and a dispersion medium are provided. And a dispersion fluid comprising a colorant constituting a background portion and, if desired, a thickener.

The magnetophoretic display panel according to claim 2 is
According to the first aspect of the present invention, the multi-cell structure is a honeycomb type.

According to a third aspect of the present invention, there is provided a magnetophoretic display panel.
The invention according to claim 1 is characterized in that the multi-cell structure is a microcapsule type.

[0013]

With the configuration described above, the responsiveness of the magnetophoretic display panel to the magnetic pen is improved. This can be attributed to the large surface area of the deformed magnetic particles. In addition, since the magnetic particles are irregularly shaped, the coloring properties of the color paint are good, and the peeling of the paint upon use is small, so that there is an advantage that deterioration with time is small, and stainless steel particles with a thin ground color are used. Therefore, the original color of the color paint can be visually recognized as compared with ferrite or magnetite, and a vivid color display can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The same or equivalent members as those described in the section of the related art will be described with the same reference numerals.

The appearance of the magnetophoretic display panel 10 according to the present invention is the same as that of the conventional one shown in FIG. 1 and will be described with reference to FIG. As shown in the figure, this magnetophoretic display panel 10 also has two non-magnetic panels 12a and 12b facing each other as in the conventional one, and the panel 12a
Is the viewing side and panel 12b is the non-viewing side. A large number of partitions 14 are provided between the panels 12a and 12b, and a large number of honeycomb cells 16 are formed by the partitions 14 and the panels 12a and 12b.

Inside the cell 16, a dispersion fluid 20 comprising magnetic particles 18, a dispersion medium, a colorant constituting a background portion and, if desired, a thickener is sealed. When the surface of the panel 12a is traced by the magnetic pen 22, the magnetic particles 18 are attracted and migrate to reach the back surface of the panel 12a, and the color difference between the colorant for displaying the background and the magnetic particles 18 causes the magnetic pen 18 to be applied to the surface of the panel 12a. The character traced in step 22 is displayed.

Next, the magnetic particles 18 used here are used.
Will be described. The magnetic particles 18 are stainless steel particles, whose components are: carbon C... 0.03% or less, silicon Si... 1.5% or less, manganese Mn... 0.3% or less, phosphorus P: 0.04% or less Sulfur S: 0.03% or less Nickel Ni: 0.6% or less Chromium Cr: 11.5 to 13.5% Iron Fe ... remaining

As shown in the sectional view of FIG.
It is odd. Here, the irregular shape means that the shape of the particles is not unified to a specific shape such as a sphere or a substantially rectangular parallelepiped, and each particle has a different shape.
Further, it is preferable that the surface is formed with a complicated uneven surface.

The particle size is measured on the long diameter side,
It is distributed in the range of 30 to 100 μm, and the average particle size is 7
It is 0 to 75 μm.

The magnetic particles 18 are made of stainless steel composed of the above-mentioned components, but are manufactured by a water atomizing method in order to make the particles irregular. In addition, the water atomizing method is a method of injecting high-pressure water into molten steel to powderize the steel. Due to the wide range of size distribution of the particles produced by this method, the above ranges are determined by sieving and excluding other parts.

Next, the color coloring of the magnetic particles 18 will be described. An acrylic resin paint is used as the paint. Polyurethane, epoxy or vinyl chloride may be used, but acrylic is superior in that it is less likely to peel off, and has good gloss and good water and oil resistance.

Next, the pigment to be mixed into the paint will be described. The pigment was implemented for four colors of blue, yellow, green and red. Blue pigment: Melamine / toluenesulfonamide resin fine particles colored with a fluorescent dye, with good solvent resistance and clear color. Yellow pigment: Inorganic pigment mainly composed of chrome yellow (PbCrO4) and chromium zinc, having high coloring power and hiding power. Green pigment: Chromium oxide (Cr2O3), an inorganic pigment with high stability to chemicals. Red pigment: azo organic pigment. In addition, acetone and toluene were used as a solvent.

The coloring of the magnetic particles 18 is performed by a spray dryer method, the drying temperature is 130 ± 2 ° C., and the drying time is 3 seconds. No pre-processing was performed. Thus, a colored film having a thickness of 20 to 30 μm was formed on the surface of the magnetic particles 18. In addition, ultramarine, aniline blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue,
Pigments and dyes such as phthalocyanine green can also be used.

The magnetic particles 18 produced as described above
Since the material is stainless steel, the saturation magnetization is lower by about 10% than that of ferrite or the like. This can be dealt with by increasing the magnetic force of the magnetic pen by 20%. Since the stainless steel is used, the color of the colorant can be displayed without deteriorating the original color without having a light ground color and not being covered with a silver-white concealing film or the like. In addition, since the magnetic particles 18 are irregularly shaped, they have a better magnetic sensitivity than a spherical shape, a good adhesion of the paint, and are hardly rusted. is there.

Further, by coloring the magnetic particles 18 as described above, the heat resistance can be improved.
At a temperature of ° C., the magnetic particles solidify in a dumpling shape, whereas in the case of the magnetic particles 18 in this embodiment, such a phenomenon is not observed.

Next, a second embodiment of the present invention will be described.
This will be described with reference to the drawings. The same or equivalent members as those described in the first embodiment are denoted by the same reference numerals.

As shown in FIG. 3, the magnetophoretic display panel 30 according to the second embodiment has two non-magnetic panels 12a and 12b facing each other. The non-visual side. These panels 12
A large number of spherical microcapsules 26 are accommodated between a and 12b, and the microcapsules 26 form a multi-cell structure. Inside the microcapsules 26, the honeycomb-type cells 16 in the first embodiment are provided.
A dispersion fluid 20 composed of the same magnetic particles 18 made of colored stainless steel, a dispersion medium, a colorant constituting a background portion, and, if desired, a thickener, is contained therein. It is enclosed.

The microcapsules 26 are made of the magnetic particles 18.
A dispersion fluid 20 comprising a dispersion medium, a colorant constituting a background portion, and, if desired, a thickener;
It is composed of a shell material such as a polymer covering the shell. The resin used as the shell material generally includes an acrylic resin, a methacrylic resin, a polystyrene resin, a polyester resin, a polyurethane resin, a polyamide resin, an epoxy resin, and the like. Alternatively, they are used in combination.

The method for producing the microcapsules 26 includes a phase separation method in which a dense layer of polymer is separated around a dispersion fluid 20 serving as a core material dispersed in a polymer solution, and a method of forming a polymer around a core material in a polymer solution. In-liquid curing coating method in which the polymer is cured with a curing test agent, etc., in-situ weight covering the surface of the core material with polymer by supplying a monomer or polymerization catalyst from either the inner or outer phase of the emulsion in which the core material is dispersed There is a law. In particular, phase separation methods,
According to the in-situ polymerization method, the particle size is uniform, and the magnetic particles 1
The microcapsules 26 that can easily move the microcapsules 8 can be manufactured.

When the surface of the panel 12a on the visual side of the thus formed magnetophoretic display panel 30 is traced with the magnetic pen 22, the magnetic particles 18 are attracted and the microcapsules 2 are drawn.
6, the microcapsules 26 on the panel 12a side
Colorant and magnetic particles 1 reaching back and displaying background
The characters and the like traced with the magnetic pen 22 are displayed on the surface of the panel 12a in a color difference from the color 8. The panel 12a uses an opaque, for example, white light diffusing plate so that the color of the magnetic particles 18 cannot be seen through from the viewing side when there is no display.

Next, in order to erase the characters and the like once displayed, the erasing magnet 24 arranged on the back of the non-visual side panel 12b is slid along the surface of the panel 12b. Then, the magnetic particles 18 attracted to the back surface of the microcapsules 26 on the panel 12a side migrate inside the microcapsules 26 in the direction of the panel 12b, reach the back surface of the microcapsules 26 on the panel 12b side, and When viewed from the side, only the color of the dispersion fluid 20 is visible, and the display of characters and the like has been deleted.

[0032]

As described above, according to the present invention,
A magnetophoretic display in which a multi-cell structure is formed between two substrates, and a dispersion fluid comprising magnetic particles, a dispersion medium, a colorant constituting a background portion, and, if desired, a thickener is sealed in these cells. In the panel, as the magnetic particles, the deformed stainless steel particles whose surface was colored were used,
Compared with ferrite or magnetite, the ground color is lighter and the original color of the color paint can be visually recognized, and a vivid color display can be performed. Further, since the magnetic particles are irregular in shape, the responsiveness to the magnet is good, the adhesion of the color coating is good, and the coating is hardly rusted.

[Brief description of the drawings]

FIG. 1 shows a part of a magnetophoretic display panel which has been conventionally used and is also a first embodiment of the present invention, wherein (a) is a cross-sectional view and (b) is a plan view.

FIG. 2 is a cross-sectional view of a magnetic colored irregular shaped magnetic particle.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

DESCRIPTION OF SYMBOLS 10 Magnetophoretic display panel 12a Viewing side panel 12b Non-viewing side panel 14 Partition wall 16 Cell 18 Magnetic particles 20 Dispersion fluid 22 Magnetic pen 24 Permanent magnet 26 Macro capsule 30 Magnetophoretic display panel

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Claims (3)

[Claims] 1. A multi-cell structure is formed between two substrates, and in these cells, magnetic particles composed of irregularly shaped stainless steel particles having a colored surface, a dispersion medium, and a background portion are formed. A magnetophoretic display panel in which a dispersion fluid comprising a colorant and, if desired, a thickener is enclosed. 2. The magnetophoretic display panel according to claim 1, wherein the multi-cell structure is a honeycomb type. 3. The magnetophoretic display panel according to claim 1, wherein the multi-cell structure is of a microcapsule type.