JP2002049062A - Magnetophoresis display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetophoresis display panel using the magnetic particles having reduced particle size, excellent response to magnetic force and excellent coloring property and not impairing colors of colorants. SOLUTION: In the magnetophoresis display panel having a multi-cell structure between two sheets of substrates and enclosing a dispersion liquid consisting of the magnetic particles, a dispersion medium, the colorants and optionally an extender in the cells, the magnetophoresis display panel is characterized by using the magnetic particles composed of spherical stainless steel particles having surfaces coated with 1-6 μm composite oxide type pigment and having 45-150 μm particle size.

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 As shown in FIG. 4, a conventional magnetophoretic display panel 10 comprises two opposing substrates, a panel 11 on a viewing side.
And a panel 12 on the non-viewing side. A honeycomb-shaped partition wall 14 is provided between the panels 11 and 12, as shown in FIG.
6 are formed. Inside the cell 16, a dispersion liquid 20 comprising magnetic particles 18, a dispersion medium, a colorant constituting a background portion, and, if desired, an extender is sealed.

When the magnetic pen 22 is stroked from above the panel 11, the magnetic particles 18 attracted by the magnetic force migrate from the panel 12 side to reach the panel 11, and the contrast between the dispersion liquid 20 and the magnetic particles 18 is increased. , A black-and-white display is formed. An erasing magnet 24 is movably provided on the lower surface of the panel 12.

[0004] In addition to the black-and-white display magnetophoretic display panel, there is a magnetophoretic display panel capable of color display. In this case, the magnetic particles 18 of the above-mentioned material and the color resin are kneaded and pulverized. Since the pulverized particles are irregular in shape with a large number of acute angles, when sucked by the magnetic pen 22, they do not come into plane contact with the panel 11,
A gap is formed between the panel 11 and the magnetic powder. When this is viewed through the panel 11 on the visual side, color particles are seen behind the white color of the dispersion liquid, and it looks like a hazy color,
There was a drawback that the entire display was unclear.

[0005] In particular, when coloring black irregular shaped particles,
A large area of the particles is required, and a large amount of paint needs to be applied, especially for the coating at the sharp vertex. A large amount of paint results in weakening the magnetic force of the magnetic particles, and has a serious drawback that a clear image cannot be obtained.

[0006]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned conventional disadvantages. In particular, the present invention reduces the particle size of magnetic particles, and has good responsiveness to magnetic force, good colorability, and good color of a colorant. An object of the present invention is to provide a magnetophoretic display panel using intact magnetic particles.

[0007]

The magnetophoretic display panel of the present invention has a multi-cell structure between two substrates, in which magnetic particles, a dispersion medium, a colorant, and if necessary, an extender. Magnetic particles made of spherical stainless steel particles having a particle size of 45 μm to 150 μm, the surface of which is coated with a composite oxide pigment having a particle size of 1 to 6 μm in a magnetophoretic display panel enclosing a dispersion liquid composed of It is.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The magnetophoretic display panel of the present invention has a multi-cell structure between two substrates as in the conventional type. In this cell, magnetic particles, a dispersion medium, a colorant, , A dispersion liquid comprising a bulking agent is enclosed. As shown in FIG. 1, color magnetic particles 1 having substantially spherical stainless steel particles 2 and a colored layer 3 formed by coloring on the surface thereof are used in the dispersion liquid.

The stainless steel particles 2 are formed by the following components. Carbon C 0.03% or less Silicon Si 0.1% or less Manganese Mn 0.5% or less Sulfur S 0.03% or less Nickel Ni 0.6% or less Phosphorus P 0.04% or less Chromium Cr 11.0% or less Iron Fe remains. The cross-sectional shape of the stainless steel particles 2 is almost spherical as shown in FIG.

The color magnetic particles 1 have a particle size distributed in the range of 45 to 150 μm on the major axis side, and have an average particle size of 75 to 100 μm. The reason for limiting to these numerical values is that, for example, when coating is performed on particles having a size of 45 μm or less, particles that are coated on the entire surface and particles that are coated on the spots are formed, and are separated and incomplete. Also, 150
When particles having a size of μm or more are displayed in color on a magnetophoretic display panel using a magnetic pen, there is a possibility that the edges of the display line width by the magnetic pen are not uniform, and the gap between the color magnetic particles is unclear. Taking these into account, the magnetic particle diameter is set to 45
It was determined in the range of μm to 150 μm.

As the spherical stainless steel particles 2 forming the color magnetic particles 1, those produced by a water atomizing method are used. In the water atomization method, high-pressure water is injected into a molten stainless steel with a large number of injection nozzles, and atomized in a water atomizing device to cause surface tension due to the physical properties of the molten metal to form a spherical shape. In addition, in order to make the said average particle size, what was sieved is used.

Next, the colored layer 3 formed on the surface of the substantially spherical stainless steel particles 2 will be described. The specific gravity of the composite oxide-based pigment is limited to a value of 3.0 to 6.5 CGS, for example, when the surface of the stainless steel particles 2 is coated with a tumbling fluidizer, the specific gravity is 3.0 CGS.
The following paints cannot be applied because the injected paints fly in the air and do not become entangled with the magnetic particles in the pot of the tumbling fluidizer. Further, the paint of 6.5 CGS or more sinks to the bottom of the kettle of the tumbling fluidizer, does not get entangled with the magnetic particles, and cannot be painted. Therefore, the specific gravity of the composite oxide-based pigment was set in the range of 3.0 to 6.5 CGS. The composite oxide pigment is excellent in oil resistance, water resistance and chemical resistance, and is also excellent in that it is difficult to peel off.

Next, the following pigments are used for the blue, yellow, green and red colors to be mixed into the paint. That is, yellow pigment: cobalt oxide, titanium oxide, nitrite oxide. Green pigment: titanium oxide, cobalt oxide, nitrite oxide, zinc oxide. Blue pigment: cobalt oxide, aluminum oxide. Red pigment: Iron oxide. With the above physical properties, a clear pigment specific gravity of 3.0 to 6.5 CGS could be obtained.

The coating of the magnetic particles having a size of 45 μm to 150 μm has been made possible by finely forming the composite oxide pigment. That is, complete coating cannot be performed unless the composite oxide pigment is pulverized to a particle size of 1 to 6 μm. According to the present invention, a composite oxide pigment of 1 to 6 μm could be obtained by utilizing an ultrafine pulverizer. This is a kind of pin mill, in which two disks with a large number of pins are rotated at a high speed, and the pigments are finely pulverized by the interaction of impact and repulsion by engaging the pins. For example, by setting the relative rotation speed of the disk to an extremely high speed of 210 m / sec, it becomes possible to ultrafinely pulverize the pigment by the impact, whereby the composite oxide pigment is 1 to 6 μm and the specific gravity is 3. 0 to
6.5 CGS could be obtained.

In the above-mentioned coating, stainless steel particles 2 of magnetic particles are put into a rolling fluidizing device, and the particles are blown up with air in the device to roll. Here, after the magnetic particles are wet, the powder of the paint is adsorbed to form a compacted sphere. It is removed from the tumbling fluidizer after it has been dried and consolidated. The spray pigment liquid used for the above coating is pigment 2
3%, 2% titanium oxide, 37% resin solution, 38% water, trace amounts of additives. The coating liquid is 50% resin liquid,
50% water.

Since the color magnetic particles 1 manufactured as described above are made of stainless steel, the saturation magnetization is about 10% lower than that of ferrite or the like. Alternatively, it can be dealt with by increasing the use of neodymium iron boron by 20%. Further, since the stainless steel is used, the background color is thin, and the colorant can be displayed without impairing the colorant even if it is not covered with a silver-white concealing film.

Since the color magnetic particles 1 are spherical, their surface area is small, their magnetic sensitivity is higher than that of irregularly shaped particles having an acute angle, and the paint has good adhesion and rust. Since it is difficult to use, there is an advantage that peeling of the paint due to use is small and deterioration with time is small.

FIG. 2 shows a configuration example of a magnetophoretic display panel using the color magnetic particles 1 of the present invention. FIG. 3A shows a multi-cell structure between two substrates, a red dispersion liquid 31 containing red color magnetic particles, a yellow dispersion liquid 32 containing yellow color magnetic particles, and a blue dispersion liquid. This is a display panel in which a blue-yellow dispersion liquid 33 containing color magnetic particles and a green dispersion liquid 34 containing green color magnetic particles are arranged vertically. Similarly, (b) shows a red dispersion liquid 31, a yellow dispersion liquid 32, and a blue yellow dispersion liquid 3
3 shows a configuration example of a display panel in which green dispersion liquids 34 are arranged side by side.

FIG. 3 shows a color development in the case where hiragana “to” is drawn on the magnetophoretic display panel of FIG. 2 using a magnetic pen. That is, in FIG. 3C, the characters "to" are color-coded in order from the top corresponding to the arrangement of the respective color dispersion liquids on the display panel. Similarly, in (d), the characters “to” are displayed side by side and color-coded.

[0020]

EXAMPLE The apparent density of the above color magnetic particles was 2.10 g.
/ Cm ³ .

[0021]

As described above, according to the magnetophoretic display panel of the present invention, spherical stainless steel particles having a colored surface are used as the magnetic particles. They can be easily arranged in order on the back of the panel. As a result, the ground color is lighter than the conventional one using ferrite or magnetite, and the original color of the color paint can be visually recognized. Also,
Since the color magnetic particles are spherical, the surface area is small, the responsiveness to the magnetic force of the magnetic pen is improved, the adhesion of the color paint at the time of painting is good, it is hard to rust, the paint peels off due to use, and the deterioration over time Can be reduced.
In particular, when the magnetic particles are formed to have a small particle diameter in the range of 45 μm to 150 μm, the color magnetic particles can be arranged in a more ordered manner when they are sucked by a magnetic pen, and can be densely packed. As a result, the distance between the color magnetic particles becomes narrower and smaller, and the white color of the dispersion liquid cannot be seen with the naked eye from between the color magnetic particles from the viewing side panel,
The edges of the line width were also irregular, and the jaggedness could not be seen with the naked eye, and a clear image could be obtained. Furthermore, the denseness of the color magnetic particles makes it possible to form a clearer image with a deeper color of the displayed image.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of color magnetic particles used in a magnetophoretic display panel showing one embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement example of color magnetic particles of the magnetophoretic display panel of the present invention.

FIG. 3 is a plan view showing an example of coloring of characters drawn on the magnetophoretic display panel of the present invention.

FIG. 4 is a sectional view of a main part of a conventional magnetophoretic display panel.

FIG. 5 is a sectional view of a main part of a partition wall in a conventional magnetophoretic display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Color magnetic particle 2 Spherical stainless steel particle 3 Colored layer 10 Magnetophoretic display panel 11 Visual side panel 12 Non-visual side panel 14 Partition wall 16 Cell 18 Magnetic particle 20 Dispersion liquid 22 Magnetic pen 24 Erase magnet 31 Red dispersion liquid 32 Yellow Dispersion liquid 33 Yellow dispersion liquid 34 Green dispersion liquid

Claims (1)

[Claims] 1. A magnetophoretic display panel in which a multi-cell structure is provided between two substrates, and a dispersion liquid comprising magnetic particles, a dispersion medium, a colorant and, if desired, an extender is sealed in the cells. A magnetophoretic display panel comprising spherical stainless steel particles having a particle diameter of 45 μm to 150 μm, the surfaces of which are coated with a 1-6 μm composite oxide pigment.