JPS6022333B2 - Magnetophoretic display method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a magnetic sardine, which applies a magnetic field to a plastically fluid powder in which magnetic particles are dispersed, and controls the migration and retention properties of the magnetic particles by magnetic force, thereby displaying high performance. Regarding display method.

Tsubaki Sekisho 48-15 as a display method applying the magnetic phoresis phenomenon
A method described in Japanese Patent No. 6393 is known.

In this method, a magnetic field is applied to a colored dispersion device in which magnetic fine powder of a different color from the dispersion medium is dispersed, and the magnetic fine powder is caused to migrate due to the magnetic force, and the color of the colored dispersed butterfly is changed and displayed. However, there is a serious drawback that the stability and high speed of display are hindered because the retention and migration properties of the magnetic fine particles conflict with each other. That is, in order to prevent the magnetic particles from settling and improve the stability of the display, if a substance with a low specific gravity is attached to the magnetic particles, the magnetic force acting on the magnetic particles becomes extremely small, and no display occurs. The display can only be expressed as broken points. In addition, in a normal liquid without a yield value, the continuous movement of magnetic particles cannot be stopped, and a clear display cannot be obtained. The present invention does not have any of the drawbacks of the above methods, and can adjust the retention of magnetic particles to improve display stability.
The display speed can be adjusted by controlling the electrophoretic speed of the magnetic particles, and the magnetic particles can be electrophoresed only when the yield value is exceeded, resulting in a clear display.

As a result of research on magnetophoretic display methods, the present inventor found that the above-mentioned characteristics can be imparted by using plastic flow powder as the dispersed soot of magnetic particles.

Generally, the fluidity of a plastically fluid powder is determined by the yield value leading to flow and the flow viscosity during flow, but the yield value and flow viscosity can be controlled independently. In the magnetophoretic sardine display method, when plastic flowable powder is used as a dispersion medium for magnetic particles, the stability of the display can be achieved by adjusting the retention property based on the yield value of the plastic flow powder.
Furthermore, since the magnetic particles in the plastic-flowable powder migrate when the magnetic force due to the action of the magnetic field exceeds the yield value, it is clear that the magnetic particles are mixed relatively uniformly, and the migration region and non-migration region are distinct. In other words, by utilizing the property that magnetic particles do not move unless a magnetic force greater than the yield value is applied to a plastically fluid powder, the magnetic particles can be electrophoresed, resulting in a clear display. . In the present invention, since the yield value and flow viscosity of the plastic flowable powder can be controlled, a wide range of magnetic particles with large specific gravity and large grain size can be used. Furthermore, a wide range of powders can be used by appropriately adjusting the apparent specific gravity and the like. Since the yield value of plastic flowable powder can be controlled, it is possible to display and erase displays using various magnetic forces. In the present invention, plastic flowable powder is particularly used as a dispersant for magnetic particles.

Plastic-flowable powders behave similarly to plastic-flowable liquids, but
It has the advantage that its yield value does not change due to temperature changes, is extremely strong in terms of sunlight fastness, and can withstand harsh usage conditions, and its composition does not change at all due to evaporation during use. It has advantages. It also shows performance comparable to plastic flowable powder in terms of display clarity. Furthermore, when plastic-flowable powder is incorporated into a magnetic display device as described below, minute bubbles are likely to be generated inside the panel's display board, that is, on the surface of the liquid, due to temperature changes. No such bubbles are generated, and the clarity of the display is even better. The plastically fluid powder used in the present invention includes various powders, such as finely powdered silica and alumina prepared by a dry process, but other materials exhibiting plastically fluidic properties can also be used as appropriate.

It is preferable to impart coloring properties and hiding power to the plastic fluid powder to enhance the contrast with the magnetic particles, so various dyes and pigments may be added in the form of powder and mixed and dispersed.
Various dyes and pigments can be added and mixed in the form of solutions or dispersions, and then dried again to prepare colored plastic-flowable powders.

The magnetic particles used in the present invention include magnetic materials with high magnetic permeability, such as oxide magnetic materials such as black magnetite, y-hematite, chromium dioxide, and ferrite, iron, cobalt,
An alloy-based metallic material such as nickel, which is used in the form of powder or flakes, or by granulation to adjust the size, shape, color tone, etc.

Magnetic particles can be used in sizes ranging from fine particles to coarse particles depending on the purpose, and can be used in shapes such as spherical, columnar, lumpy, and flaky. The magnetic particles can be mixed with various coloring agents or their surfaces can be coated with various coloring agents to give them a different color tone from their inherent color. Incidentally, if there is variation in the size of the magnetic particles, the electrophoretic properties will also vary, so making them uniform is good for display clarity. Next, a description will be given of an embodiment of the enchantment carried out by the present invention.

In the bag demon shown in the first diagram, a transparent front plate 1 and a transparent or opaque back plate 2 (transparent ones are made of plastic, glass, etc., opaque ones are made of metal, etc.) are made of plastic fluid powder in which magnetic particles 3 are dispersed. A partition 5 is placed perpendicularly to the surface plate 1.
is provided. The partition 5 is used to prevent unevenness in the amount of magnetic particles 3 adsorbed to the outer surface of the surface plate 1 per unit area, which will be described later. You can use sheet materials such as
It can also be integrally molded with the front plate 1 or the back plate 2.
To display, a permanent magnet or an electromagnetic erasing magnet 6 is scanned over the surface of the back plate 2 to apply a magnetic field to the plastic fluid powder 4 to attract the magnetic particles 3 to the back surface of the back plate 2. A magnetic marker made of a magnet or an electromagnet or a recording magnet 7 of a magnetic head is moved on the surface of the top plate 1 or a current is applied to apply a magnetic field to the plastic fluid powder 4 to form magnetic particles 3 on the back side of the top plate 1. The plastic fluid powder 4 is adsorbed to create a contrast and display is performed. In the above embodiment, if the two magnetic poles of the magnetic particles 3 are colored in different colors as shown in the second figure, two-color display can be achieved by selecting the polarity of the recording magnet.

In the embodiment shown in the third figure, a columnar permanent magnet 8 is inserted between each of the partitions 5 configured in the same manner as the first figure,
Display can be performed using the recording magnet 7.

In the present invention, the surface plate may be positioned not only horizontally but also vertically or diagonally.

Next, examples of the present invention will be described.

10 parts of Aerosil and 1 part of Shiroenka○ (finely powdered calcium carbonate from Nisseki Kogyo Co., Ltd.) were thoroughly mixed to prepare a white plastically fluid powder.

Two parts of MRMP-450 (Magnetite manufactured by Toda Kogyo ■) and five parts of a 20% toluene solution of Acrybet VK (Tacrylic resin manufactured by Mitsubishi Rayon ■) are kneaded with three rolls, dried, and crushed to give a 100% ~25 black magnetic particles 2
Got Kibe.

These magnetic particles were uniformly mixed with the plastic flowable powder and filled into a white PVC perforated plate (cell size 3, thickness 2 ribs) to which a transparent polyester film was adhered as a top plate, and a A 0.5 kite transparent vinyl chloride sheet was heat-sealed to make it a fake.

The surface of the back sheet was scanned with an erasing magnet made of a ferrite magnet magnetized on both sides, and a recording magnet made of a samarium-cobalt alloy magnet was used to record from the surface of the front sheet, resulting in a clear black display on a white background. .

When the sheet on the hair surface was scanned with an erasing magnet, the display could be quickly erased. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 3 are partially omitted cross-sectional views of an apparatus for carrying out the present invention, and FIG. 2 is an enlarged view of magnetic particles in another embodiment of the apparatus of FIG. 1.

1... Surface plate, 2... Back plate, 3... Magnetic particles,
4... Plastic flowable powder, 5... Partition, 6... Erasing magnet, 7... Recording magnet, 8... Permanent magnet.

Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A magnetophoretic display method in which display is performed by applying a magnetic field greater than the yield value to a plastic fluid powder having a yield value in which magnetic particles are dispersed to cause the magnetic particles to migrate.