Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2001-11-28
2004-12-28
Ngo, Julie-Huyen (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S155000, C430S007000
Reexamination Certificate
active
06836304
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing an image display medium, and more specifically to a method of manufacturing an image display medium that can display an image repeatedly, and to an image display medium.
2. Description of the Related Art
Hitherto, electronic paper technology for displaying desired images on a display substrate utilizing an electric power has become known. When broadly classified, such electronic paper technology includes constructions in which a liquid display element or a display liquid with a display element dispersed in a liquid is encapsulated between opposed substrates, as in the case of technologies such as electrophoresis, thermal rewritability, liquid crystals, and electrochromy are used, and constructions in which a powder-type display element such as a toner is encapsulated between the opposed substrates, as in the case of a construction in which conductive coloring toner
96
and white particles
98
are encapsulated between two display substrates
90
a
,
90
b
each constructed with a matrix electrode
92
and an electric charge transferring layer
94
laminated in sequence, as shown in FIG.
20
.
A method of manufacturing electronic paper in the former construction, in which a liquid display element or a display liquid obtained by dispersing a display element in a liquid is encapsulated between the opposed substrates, is generally known. For example, a liquid crystal display is produced by forming a vacuum between the substrates and causing the liquid display element, or the display liquid with the display element dispersed in the liquid, to be sucked between the substrates.
However, a method of manufacturing electronic paper in the latter construction, in which a powder-type display element such as toner is encapsulated between the opposed substrates, is not generally known. A method comprising steps of dispersing powder bodies in carrier fluid, filling the carrier fluid from an opening into a vacuumed space between substrates, and evaporating the carrier fluid is conceivable as a technique for producing electronic paper with such a construction. However, this is difficult and it is not practical to completely evaporate the carrier fluid filled between the substrates from the opening. In addition, when the substrates are fixed by a spacer, a problem of deterioration of display due to trapping of the powder bodies may arise.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to encapsulate a prescribed amount of a powder-type display element uniformly between opposed substrates. It is another object of the present invention to provide a method of manufacturing an image display medium, and an image display medium, in which a powder-type display element can be encapsulated uniformly between opposed substrates and irregularities in displayed images due to trapping of powder bodies may be prevented.
In order to achieve the objects described above, a method of manufacturing an image display medium according to a first aspect of the present invention includes steps of: providing substantially flat substrates, one of which having at least one spacer disposed thereon; disposing a plurality of color material particles distributed substantially uniformly on at least one of the substrates; while maintaining a predetermined amount of the plurality of color material particles distributed on the at least one substrate, superimposing another substrate thereon; and using the at least one spacer to fix the substrates to one another.
That is, according to the first aspect of the present invention, a prescribed amount of the color material particles is encapsulated uniformly between two opposed substrates by fixing the first substrate and the spacer of the second substrate in a state in which the color material particles are held on the first substrate, the spacer-side of the second substrate, or both the first substrate and the spacer-side of the second substrate.
Especially, when using two types of color material particles having different electrostatic properties, it is preferable to attach the color material particles having one of the electrostatic properties to the first substrate and the color material particles having the other electrostatic property to the spacer-side of the second substrate.
In other words, since the first substrate and the spacer of the second substrate are fixed with each other in the method of manufacturing the image display medium according to the first aspect, the distance between the first substrate and the second substrate is kept constant. In addition, since the color material particles are held on at least one of the substrates, the color material particles can be encapsulated uniformly over the whole area thereof without causing a disadvantage that the amount of the color material particles encapsulated between the first substrate and the second substrate varies between areas divided by the spacer, including a case where some areas have no color material particles at all.
In order to distribute the color material particles uniformly, the color material particles may be attached to one or both of the first and the second substrates by transferring the particles a prescribed distance by an electric field.
For example, a method utilizing an electrostatic recording system, which includes steps of charging the color material particles and attaching the charged color material particles directly to a substrate formed with an electrostatic latent image on a surface thereof, or of attaching the charged color material particles to an intermediate transfer body formed with an electrostatic latent image on a surface thereof, and then transferring the charged color material particles from the intermediate transfer body to the substrate, may be employed. In addition, the color material particles can be applied in a desired pattern by using electrostatic recording methods such as electrophotographic technology, a multi-stylus electrode, liquid development, electrostatic application, and so on.
Alternatively, a method of simply supplying the color material particles to the substrate and holding the particles on the substrate or the like may be employed. Examples of this method include screen printing, blade coating, roll coating, spray coating, gap coating, and bar coating, and the layer of color material particles may be applied on the substrate by supplying the color material particles with these methods.
Alternatively, the color material particles may be distributed uniformly by dispersing the color material particles in gas and supplying the gas to at least one of the first and the second substrates.
For example, a particle falling method, in which the color material particles are suspended in a space by air blowing or the like, and the substrate is held or passed in the space for a predetermined period of time so that the color material particles are allowed to drop down to form a uniform layer of color material particles on the substrate, may be employed.
Alternatively, a method using magnetic recording, in which color material particles including magnetic bodies therein are held directly on a substrate formed with a magnetic pattern on the surface thereof, or the color material particles are held on an intermediate transfer body formed with a magnetic pattern on the surface thereof and then transferred from the intermediate transfer body to the substrate and held thereon, may be employed. By using magnetography as a magnetic recording method, the color material particles can be applied in a desired pattern.
The color material particles can also be distributed uniformly by supplying them to at least one of the first substrate and the second substrate in a state of being dispersed in a liquid.
For example, a method which includes steps of dispersing the color material particles in a carrier fluid, holding the carrier fluid including the color material particles on the surface of a substrate, and evaporating the carrier fluid so that o
Kakinuma Takeo
Koshimizu Minoru
Machida Yoshinori
Matsunaga Takeshi
Nakayama Nobuyuki
Fuji 'Xerox Co., Ltd.
Ngo Julie-Huyen
Oliff & Berridg,e PLC
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