JP2007102042A - Method for refining electrophoresis particle, particle fluid dispersion using same, and image display medium/device - Google Patents

Method for refining electrophoresis particle, particle fluid dispersion using same, and image display medium/device Download PDF

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JP2007102042A
JP2007102042A JP2005294107A JP2005294107A JP2007102042A JP 2007102042 A JP2007102042 A JP 2007102042A JP 2005294107 A JP2005294107 A JP 2005294107A JP 2005294107 A JP2005294107 A JP 2005294107A JP 2007102042 A JP2007102042 A JP 2007102042A
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JP4911942B2 (en
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Masahiro Yanagisawa
匡浩 柳澤
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Ricoh Co Ltd
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<P>PROBLEM TO BE SOLVED: To provide an image display medium and a device which have a superior display contrast between white display and colored display by removing phoresis particles having abnormal electrostatic charging performance for electrophoresis display. <P>SOLUTION: A method for refining electrophoresis particles is characterized in that only electrodeposited particles are collected after two electrode substrates are dipped in fluid dispersions prepared by dispersing particles having electrophoretic property in a nonpolar solvent and a DC voltage is applied between their electrodes to electrodeposit the particles on one electrode substrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、画像表示媒体用電気泳動粒子、ならびにそれを用いた電気泳動粒子分散液、画像表示媒体及び画像表示装置に関する。   The present invention relates to an electrophoretic particle for an image display medium, an electrophoretic particle dispersion using the same, an image display medium, and an image display device.

従来、文字や静止画、動画等のいわゆる画像の表示用端末としてCRTや液晶ディスプレイが用いられている。これらはデジタルデータを瞬時に表示し、書き換えることができるが、装置を常に持ち歩くことは困難であり、長時間の作業では眼が疲労したり、電源をオフにしては表示できないなど多くの欠点もある。一方、文字や静止画を書類などとして配布や保存するときは、プリンタにて紙媒体に記録される。この紙媒体は、いわゆるハードコピーとして、広く使用されているものである。ハードコピーは、ディスプレイより文章を読みやすく、疲れにくく、自由な姿勢で読むことができる。さらに、軽量で自由に持ち運びが可能である特徴を有する。しかし、ハードコピーは使用された後は廃棄され、リサイクルされるが、そのリサイクルには多くの労力と費用を要するので省資源の点では問題が残る。   Conventionally, a CRT or a liquid crystal display is used as a terminal for displaying so-called images such as characters, still images, and moving images. They can display and rewrite digital data instantly, but it is difficult to always carry the device around, and it has many drawbacks such as eye fatigue when working for a long time and display when turning off the power. is there. On the other hand, when a character or a still image is distributed or stored as a document, it is recorded on a paper medium by a printer. This paper medium is widely used as a so-called hard copy. Hard copy is easier to read than display, less fatigue, and can be read freely. Furthermore, it has the characteristics that it is lightweight and can be carried freely. However, the hard copy is discarded and recycled after it is used. However, since the recycling requires a lot of labor and cost, there remains a problem in terms of resource saving.

以上のディスプレイとハードコピーの両方の長所を持った書き換えが可能なペーパーライクな表示媒体へのニーズは高く、これまでに高分子分散型液晶、双安定性コレステリック液晶、エレクトロクロミック素子、電気泳動素子等を用いた表示媒体が反射型で明るい表示ができ、かつメモリー性のある表示媒体として注目されている。中でも電気泳動素子を用いたものは、表示品質、表示動作時の消費電力の点で優れており、例えば、特許文献1(特開平5−173194号公報)、特許文献2(特許第2612472号公報)などに開示されている。電気泳動表示媒体では、一組の透明電極の間に、着色した分散媒中に分散媒の色とは異なる色を有する複数の電気泳動粒子を分散させた分散液を封入してある。この場合、その電気泳動粒子(単に泳動粒子とも言う)は、分散媒中で表面に電荷を帯びており、透明電極の一方に泳動粒子の電荷と逆向きの電圧を与えた場合には、泳動粒子がそちらに堆積して泳動粒子の色が観測され、泳動粒子の電荷と同じ向きの電圧を与えた場合には泳動粒子は反対側に移動するため分散媒の色が観測される。これにより表示を行なうことができる。
泳動粒子には表示・非表示状態に関わる白色・着色といった光学的性質と、外部電界に対して速やかに応答して移動するための良好な帯電性能が求められる。すなわち全ての同種類の粒子は同一極性に帯電し、電界に対して同じ方向に動く必要がある。逆極性に帯電した粒子あるいは帯電性が悪く電界に対して応答しない粒子は優れた表示特性の妨げになり、コントラストの低下といった表示媒体の視認性を悪くする要因となる。
これまで不純物を除去する手段としては液体クロマトグラフィーによる精製が特許文献3(特許第2996029号公報)に、また減圧乾燥による水分の除去による精製が特許文献4(特開2001−188267号公報)に開示されているが、電気的な手段による分離ではないため、必ずしも電気泳動性能が揃った粒子が得られるわけではない。
There is a great need for a rewritable paper-like display medium that has the advantages of both the above display and hard copy. So far, polymer-dispersed liquid crystals, bistable cholesteric liquid crystals, electrochromic devices, electrophoretic devices The display medium using the above has been attracting attention as a display medium that is reflective and can display bright and has a memory property. Among them, those using an electrophoretic element are excellent in terms of display quality and power consumption during display operation. For example, Patent Document 1 (Japanese Patent Laid-Open No. 5-173194), Patent Document 2 (Japanese Patent No. 2612472). ) And the like. In an electrophoretic display medium, a dispersion liquid in which a plurality of electrophoretic particles having a color different from the color of a dispersion medium is dispersed in a colored dispersion medium is sealed between a pair of transparent electrodes. In this case, the electrophoretic particles (also simply referred to as electrophoretic particles) are charged on the surface in the dispersion medium, and when a voltage opposite to the electrophoretic particle charge is applied to one of the transparent electrodes, the electrophoretic particles migrate. The particles are deposited there, and the color of the migrating particles is observed. When a voltage having the same direction as the charge of the migrating particles is applied, the migrating particles move to the opposite side, so the color of the dispersion medium is observed. As a result, display can be performed.
The electrophoretic particles are required to have optical properties such as white and coloring relating to the display / non-display state, and good charging performance to move quickly in response to an external electric field. That is, all particles of the same type must be charged to the same polarity and move in the same direction with respect to the electric field. Particles charged in reverse polarity or particles that are poorly charged and do not respond to an electric field hinder excellent display characteristics, and cause deterioration in visibility of the display medium, such as a reduction in contrast.
As means for removing impurities, purification by liquid chromatography has been disclosed in Patent Document 3 (Patent No. 2996029), and purification by removal of water by drying under reduced pressure has been disclosed in Patent Document 4 (Japanese Patent Laid-Open No. 2001-188267). Although disclosed, it is not necessarily a separation by electrical means, and therefore, particles having uniform electrophoretic performance are not necessarily obtained.

特開平5−173194号公報JP-A-5-173194 特許第2612472号公報Japanese Patent No. 2612472 特許第2996029号公報Japanese Patent No. 2996029 特開2001−188267号公報JP 2001-188267 A

本発明の目的は、電気泳動表示において上記問題を解決して帯電性能が異常である泳動粒子を除去することにより、白色表示および着色表示の間の表示コントラストが優れた画像表示媒体、装置を提供することにある。   An object of the present invention is to provide an image display medium and an apparatus having excellent display contrast between white display and colored display by solving the above-mentioned problems in electrophoretic display and removing electrophoretic particles having abnormal charging performance. There is to do.

電気泳動表示に使用される粒子は原理的に非極性溶媒中で2電極間に電圧を印加すると電界方向に沿って泳動し、いずれかの電極に電着する。このとき実際には一部の粒子は何らかの原因で逆極性に帯電していて電圧印加時に大部分の粒子とは逆の方向に泳動したり、あるいはほとんど帯電していないために電圧を印加しても電界に沿って泳動しない。これらの粒子は電気泳動粒子としてはいわば不純物であり、電気泳動表示の表示品質を損なうものであるから、電気的な手段でこれら不純物を除去することが望ましい。
そこで正常に泳動する粒子は電圧印加時に一方の電極に電着する現象に着目し、実際に非極性溶媒中で粒子分散液に浸漬した2電極間に直流電圧を印加し、一方の電極に電着した粒子のみを回収して電気泳動表示用粒子分散液を調製したところ、表示コントラストが大きく改善し、表示品質が向上することを見出した。
本発明は以上の知見に基づくものである。
In principle, particles used for electrophoretic display migrate along the electric field direction when a voltage is applied between two electrodes in a nonpolar solvent, and are electrodeposited on one of the electrodes. At this time, some particles are actually charged to the opposite polarity for some reason, and when voltage is applied, they migrate in the opposite direction to most of the particles, or the voltage is applied because they are hardly charged. Nor does it migrate along the electric field. These particles are so-called impurities as electrophoretic particles, and impair the display quality of electrophoretic display. Therefore, it is desirable to remove these impurities by electrical means.
Therefore, paying attention to the phenomenon that particles that migrate normally are electrodeposited on one electrode when a voltage is applied, a DC voltage is actually applied between the two electrodes immersed in the particle dispersion in a nonpolar solvent, and the one electrode is electrically charged. When only the attached particles were collected to prepare a particle dispersion for electrophoretic display, it was found that the display contrast was greatly improved and the display quality was improved.
The present invention is based on the above findings.

即ち、上記課題は、本発明の(1)〜(8)によって解決される。
(1)「電気泳動性を有する粒子を非極性溶媒に分散させた粒子分散液に2つの電極基板を浸漬し、これら電極間に直流電圧を印加して一方の電極基板に該粒子を電着させた後、電着した粒子のみを回収することを特徴とする電気泳動粒子の精製方法」
(2)「前記回収粒子をさらに非極性溶媒に再分散し、再度前記電圧印加および粒子回収の工程を複数回繰り返すことを特徴とする前記第(1)項に記載の電気泳動粒子の精製方法」
(3)「前記電圧印加を行なった後、さらに2電極間に逆極性の直流電圧を印加することを特徴とする前記第(1)項又は第(2)項に記載の電気泳動粒子の精製方法」
(4)「前記電着させた粒子を回収する際乃至非極性溶媒に再分散する際に、電極を非極性溶媒に浸漬し、超音波を印加することを特徴とする前記第(1)項乃至第(3)項のいずれかに記載の電気泳動粒子の精製方法」
(5)「前記前記第(1)項乃至第(4)項のいずれかに記載の精製方法により得られることを特徴とする電気泳動粒子」
(6)「少なくとも前記第(5)項に記載の電気泳動粒子を非極性溶媒に分散させることを特徴とする電気泳動粒子分散液」
(7)「所望の間隔を設けて配設された少なくとも一方が光透過性である二つの基板間に、少なくとも前記第(6)項に記載の電気泳動粒子を非極性溶媒に分散してなる分散液を含有してなり、前記二基板間に電圧を印加することによる該粒子の電気泳動により表示動作を行なうことを特徴とする画像表示媒体」
(8)「前記第(7)項に記載の画像表示媒体を構成要素に有することを特徴とする画像表示装置」
That is, the said subject is solved by (1)-(8) of this invention.
(1) “Two electrode substrates are immersed in a particle dispersion in which electrophoretic particles are dispersed in a nonpolar solvent, and a DC voltage is applied between these electrodes to electrodeposit the particles on one electrode substrate. And then collecting only the electrodeposited particles after the electrophoretic particle purification method ”
(2) “The method for purifying electrophoretic particles according to (1) above, wherein the recovered particles are further redispersed in a nonpolar solvent, and the steps of applying the voltage and recovering the particles are repeated a plurality of times. "
(3) “Purification of electrophoretic particles according to (1) or (2) above, wherein after applying the voltage, a DC voltage of opposite polarity is further applied between the two electrodes” Method"
(4) The item (1), wherein the electrode is immersed in a nonpolar solvent and ultrasonic waves are applied when the electrodeposited particles are collected or redispersed in a nonpolar solvent. Thru | or the refinement | purification method of the electrophoretic particle in any one of (3) "
(5) "Electrophoretic particles obtained by the purification method according to any one of (1) to (4)"
(6) “Electrophoretic particle dispersion characterized in that at least the electrophoretic particles according to item (5) are dispersed in a nonpolar solvent”
(7) “At least one of the electrophoretic particles according to the item (6) is dispersed in a nonpolar solvent between two substrates, at least one of which is disposed at a desired interval and is light transmissive. An image display medium comprising a dispersion and performing a display operation by electrophoresis of the particles by applying a voltage between the two substrates "
(8) “Image display device comprising the image display medium according to item (7) as a constituent element”

請求項1の発明によれば、電気泳動性を有する粒子を非極性溶媒に分散させた粒子分散液に2つの電極基板を浸漬し、これら電極間に直流電圧を印加して一方の電極基板に該粒子を電着させた後、電着した粒子のみを回収するので、帯電極性が揃った電気泳動粒子を得ることができる。
また、請求項2の発明によれば、前記回収粒子をさらに非極性溶媒に再分散し、再度前記電圧印加および粒子回収の工程を複数回繰り返すので、さらに純度が高く帯電極性が揃った電気泳動粒子を得ることができる。
請求項3の発明によれば、前記電圧印加を行った後、さらに2電極間に逆極性の直流電圧を印加することにより、電極基板に対する付着力が強い電気泳動表示に適さない粒子が除去されるので、さらに純度が高く帯電極性が揃った電気泳動粒子を得ることができる。
請求項4の発明によれば、前記電着させた粒子を回収する際乃至非極性溶媒に再分散する際に、電極を非極性溶媒に浸漬し超音波振動を加えるので、電極に電着した粒子が容易に非極性溶媒に分散するので、精製に要する時間が短縮される。
請求項5及び請求項6の発明によれば、前記の精製方法により得られた電気泳動粒子を非極性溶媒に分散させることにより、帯電極性が揃った粒子が分散された粒子分散液となるので、電気泳動表示に好適な泳動特性が優れた粒子分散液が得られる。
請求項7及び請求項8の発明によれば、少なくとも請求項6の粒子分散液を含有してなるので、表示コントラストが優れた画像表示媒体および画像表示装置を提供することができる。
According to the first aspect of the present invention, two electrode substrates are immersed in a particle dispersion in which electrophoretic particles are dispersed in a nonpolar solvent, and a DC voltage is applied between the electrodes to apply the one electrode substrate. After the particles are electrodeposited, only the electrodeposited particles are collected, so that electrophoretic particles with uniform charge polarity can be obtained.
According to the invention of claim 2, since the recovered particles are further redispersed in a nonpolar solvent, and the voltage application and particle recovery steps are repeated a plurality of times, electrophoresis with higher purity and uniform charge polarity is achieved. Particles can be obtained.
According to a third aspect of the present invention, after applying the voltage, by applying a reverse polarity DC voltage between the two electrodes, particles that are not suitable for electrophoretic display with strong adhesion to the electrode substrate are removed. Therefore, it is possible to obtain electrophoretic particles with higher purity and uniform charge polarity.
According to the invention of claim 4, when the electrodeposited particles are collected or redispersed in a nonpolar solvent, the electrode is immersed in the nonpolar solvent and subjected to ultrasonic vibration. Since the particles are easily dispersed in the nonpolar solvent, the time required for purification is shortened.
According to the invention of claim 5 and claim 6, by dispersing the electrophoretic particles obtained by the purification method in a non-polar solvent, a particle dispersion liquid in which particles having uniform charged polarity are dispersed is obtained. In addition, a particle dispersion excellent in electrophoretic characteristics suitable for electrophoretic display can be obtained.
According to the seventh and eighth aspects of the invention, since at least the particle dispersion of the sixth aspect is contained, an image display medium and an image display device having excellent display contrast can be provided.

本発明の第1の実施の形態を図1に基づき説明する。
図1において、容器(1)に精製前の電気泳動粒子分散液(2)を入れ1対の電極(3A)、(3B)を浸漬する。電気泳動粒子分散液(2)における粒子の濃度に特に制限はないが、濃度が低すぎると粒子の回収効率が悪く、一方で粒子が凝集しない程度の濃度に抑えることが望ましい。このような濃度範囲として1〜50重量%程度が適当である。1対の電極(3A)、(3B)の間に電源(4)より直流電圧を印加すると電極間の電界に沿って粒子が泳動する。例えば、電気泳動粒子が正帯電の場合、電極(3A)が+となるように電圧を印加すると粒子は電極(3B)に向かって泳動し、やがて電極(3B)上に電着する。
印加電圧は2電極間の電界強度が10〜10V/mになるようにすることが好ましい。電界強度が低すぎると粒子が泳動しにくいために電着しにくくなり、一方、電界強度が高すぎると粒子が電極に強固に電着してしまい、回収が困難になる。このようにして粒子が電着した電極(3B)を取り出し電着した粒子を回収すれば精製された電気泳動粒子が得られる。回収方法としては粒子が電着した電極基板を取り出し、加熱あるいは減圧などにより溶媒を蒸発させて残った固体粒子を集めればよい。
A first embodiment of the present invention will be described with reference to FIG.
In FIG. 1, an electrophoretic particle dispersion (2) before purification is placed in a container (1), and a pair of electrodes (3A) and (3B) are immersed therein. The concentration of the particles in the electrophoretic particle dispersion liquid (2) is not particularly limited, but it is desirable that the concentration is too low so that the particle recovery efficiency is poor, but on the other hand, the concentration is not set so that the particles do not aggregate. A concentration range of about 1 to 50% by weight is appropriate. When a DC voltage is applied from the power source (4) between the pair of electrodes (3A) and (3B), particles migrate along the electric field between the electrodes. For example, when the electrophoretic particles are positively charged, when a voltage is applied so that the electrode (3A) becomes +, the particles migrate toward the electrode (3B) and eventually electrodeposit on the electrode (3B).
The applied voltage is preferably such that the electric field strength between the two electrodes is 10 4 to 10 6 V / m. If the electric field strength is too low, the particles are difficult to migrate because the particles are difficult to migrate. On the other hand, if the electric field strength is too high, the particles are strongly electrodeposited on the electrode, making recovery difficult. Purified electrophoretic particles can be obtained by taking out the electrode (3B) on which the particles are electrodeposited in this way and collecting the electrodeposited particles. As a recovery method, the electrode substrate on which the particles are electrodeposited is taken out, and the solvent is evaporated by heating or decompression to collect the remaining solid particles.

本発明に用いられる非極性溶媒としては公知の誘電率が低く電気絶縁性が高い溶媒が使用できる。このような有機溶媒としてはペンタン、ヘキサン、ヘプタン、オクタン、ノナン、デカン、ドデカン等のパラフィン系炭化水素、イソヘキサン、イソオクタン、イソドデカン等のイソパラフィン系炭化水素、流動パラフィン等のアルキルナフテン系炭化水素、ベンゼン、トルエン、キシレン、アルキルベンゼン、ソルベントナフサ等の芳香族炭化水素、ジメチルシリコーンオイル、フェニルメチルシリコーンオイル、ジアルキルシリコーンオイル、アルキルフェニルシリコーンオイル、環状ポリジアルキルシロキサン又は環状ポリアルキルフェニルシロキサン等のシリコーンオイルが挙げられる。   As the nonpolar solvent used in the present invention, a known solvent having a low dielectric constant and high electrical insulation can be used. Examples of such organic solvents include paraffinic hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, and dodecane, isoparaffinic hydrocarbons such as isohexane, isooctane, and isododecane, alkyl naphthenic hydrocarbons such as liquid paraffin, and benzene. Aromatic hydrocarbons such as toluene, xylene, alkylbenzene and solvent naphtha, silicone oils such as dimethyl silicone oil, phenylmethyl silicone oil, dialkyl silicone oil, alkylphenyl silicone oil, cyclic polydialkylsiloxane or cyclic polyalkylphenylsiloxane It is done.

白色粒子としては、二酸化珪素、酸化アルミニウム、酸化チタンなどの金属酸化物の固体粒子が使用できる。黒色の着色粒子としては、例えば、カーボンブラック、アニリンブラック、ファーネスブラック、ランプブラック等が使用できる。シアンの着色粒子としては、例えば、フタロシアニンブルー、メチレンブルー、ビクトリアブルー、メチルバイオレット、アニリンブルー、ウルトラマリンブルー等が使用できる。マゼンタの着色粒子としては、例えば、ローダミン6Gレーキ、ジメチルキナクリドン、ウォッチングレッド、ローズベンガル、ローダミンB、アリザリンレーキ等が使用できる。イエローの着色粒子としては、例えば、クロムイエロー、ベンジジンイエロー、ハンザイエロー、ナフトールイエロー、モリブデンオレンジ、キノリンイエロー、タートラジン等が使用できる。これら着色粒子は、粒径範囲50nm〜2μm程度のものが好ましい。   As the white particles, solid particles of metal oxides such as silicon dioxide, aluminum oxide, and titanium oxide can be used. As black colored particles, for example, carbon black, aniline black, furnace black, lamp black and the like can be used. Examples of cyan colored particles include phthalocyanine blue, methylene blue, Victoria blue, methyl violet, aniline blue, and ultramarine blue. As magenta colored particles, for example, rhodamine 6G lake, dimethylquinacridone, watching red, rose bengal, rhodamine B, alizarin lake and the like can be used. As yellow colored particles, for example, chrome yellow, benzidine yellow, hansa yellow, naphthol yellow, molybdenum orange, quinoline yellow, tartrazine and the like can be used. These colored particles preferably have a particle size range of about 50 nm to 2 μm.

また、粒子を非極性溶媒に分散させる際に、粒子分散剤を使用しても良い。粒子分散剤とは粒子分散液において溶媒に対して溶解性があり、粒子存在時には該粒子に吸着性がある化合物であり、静電反発ないし分散剤分子の立体効果により粒子同士の凝集を防ぐものである。非水溶媒中で粒子が安定に分散し、分散性が良好な粒子分散液が得られる。本発明の実施の形態で使用できる粒子分散剤としては、公知の粒子分散剤として使用される界面活性剤の内、非極性溶媒に可溶なものが使用でき、好ましくは高分子系の分散剤である。なお、粒子回収時には溶媒で粒子分散剤を洗浄し取り除くことが望ましい。   Further, when dispersing the particles in a nonpolar solvent, a particle dispersant may be used. A particle dispersant is a compound that is soluble in a solvent in a particle dispersion and adsorbs to the particle when it is present, and prevents aggregation between particles due to electrostatic repulsion or the steric effect of the dispersant molecule. It is. In the non-aqueous solvent, the particles are stably dispersed, and a particle dispersion having good dispersibility can be obtained. As the particle dispersant that can be used in the embodiment of the present invention, among the surfactants used as known particle dispersants, those that are soluble in a nonpolar solvent can be used, and preferably a polymeric dispersant. It is. In addition, it is desirable to wash and remove the particle dispersant with a solvent when collecting the particles.

本発明の第2の実施の形態において、前記電圧印加および粒子回収の工程を複数回繰り返す。すなわち粒子が電着した電極から回収した粒子を再度非極性溶媒に分散し、前記の電圧印加の工程を再度繰り返すものである。この操作を繰り返すことにより泳動粒子の純度が上がり、さらに表示特性が良好になる。   In the second embodiment of the present invention, the voltage application and particle recovery steps are repeated a plurality of times. That is, the particles recovered from the electrode on which the particles are electrodeposited are dispersed again in a nonpolar solvent, and the above-described voltage application step is repeated again. By repeating this operation, the purity of the migrating particles is increased, and the display characteristics are further improved.

本発明の第3の実施の形態において、前記電圧印加を行なった後、さらに2電極間に逆極性の直流電圧を印加する。すなわち、例えば本発明の第1の実施の形態において電気泳動粒子が正帯電の場合、まず電極(3A)が+となるように電圧を印加すると粒子は電極(3B)に向かって泳動し、やがて電極(3B)上に電着する。次に電極(3A)が−となるように電圧を印加すると電極(3B)上に電着した粒子が今度は電極(3A)に向かって泳動し、やがて電極(3A)上に電着する。このような操作を行なうことにより電極基板に対する付着力が大きく一度電極基板に電着してしまうと逆方向の電界下でも二度と電極から離脱しないような電気泳動表示には適さない粒子を取り除くことができる。   In the third embodiment of the present invention, after applying the voltage, a DC voltage having a reverse polarity is further applied between the two electrodes. That is, for example, in the first embodiment of the present invention, when the electrophoretic particles are positively charged, first, when a voltage is applied so that the electrode (3A) becomes +, the particles migrate toward the electrode (3B), and eventually Electrodeposit on the electrode (3B). Next, when a voltage is applied so that the electrode (3A) becomes −, the particles electrodeposited on the electrode (3B) migrate toward the electrode (3A) and eventually electrodeposit on the electrode (3A). By performing such an operation, the adhesion force to the electrode substrate is large, and once it is electrodeposited on the electrode substrate, particles that are not suitable for electrophoretic display that do not leave the electrode again even under an electric field in the opposite direction can be removed. it can.

本発明の第4の実施の形態における電気泳動粒子の精製方法では、前記電着させた粒子を回収する際乃至非極性溶媒に再分散する際に、電極を非極性溶媒に浸漬し、超音波振動を加える。これにより電極に電着した粒子が非極性溶媒に容易に分散されるので粒子の回収に要する時間が短縮される。超音波振動を加える手段としては電極に直接加えても電極を浸漬した容器に加えても良い。   In the method for purifying electrophoretic particles according to the fourth embodiment of the present invention, when the electrodeposited particles are collected or redispersed in a nonpolar solvent, the electrode is immersed in the nonpolar solvent, and an ultrasonic wave is obtained. Add vibration. Thereby, since the particles electrodeposited on the electrode are easily dispersed in the nonpolar solvent, the time required for collecting the particles is shortened. As a means for applying ultrasonic vibration, it may be added directly to the electrode or may be added to a container in which the electrode is immersed.

本発明の第5の実施の形態において、電気泳動粒子は本発明の1乃至4の実施の形態における精製方法により得られた粒子である。電着により精製された電気粒子は帯電極性が揃っているため、電気泳動表示に適用した際には印加電圧に対して全ての粒子が同一方向に泳動するため表示コントラストが優れた表示媒体を得ることができる。   In the fifth embodiment of the present invention, the electrophoretic particles are particles obtained by the purification method according to the first to fourth embodiments of the present invention. Since the electric particles purified by electrodeposition have the same charge polarity, when applied to electrophoretic display, all particles migrate in the same direction with respect to the applied voltage, thereby obtaining a display medium with excellent display contrast. be able to.

本発明の第6の実施の形態において、電気泳動粒子分散液は少なくとも本発明の第5の実施の形態における電気泳動粒子を非極性溶媒に分散させたものである。非極性溶媒には分散粒子の分散性を制御するために分散剤などが必要に応じて添加されることもある。粒子分散液における固形分の重量割合は、所望の濃度の色が得られるように適宜設定されるが、0.1〜25重量%程度が適当である。これら各成分を非極性溶媒中に加え混合分散することにより粒子分散液を得る。この場合、分散手段としてホモジナイザー、ボールミル、サンドミル、アトライター等公知の分散手段を用いてもよい。   In the sixth embodiment of the present invention, the electrophoretic particle dispersion liquid is obtained by dispersing at least the electrophoretic particles in the fifth embodiment of the present invention in a nonpolar solvent. In order to control the dispersibility of the dispersed particles, a dispersant or the like may be added to the nonpolar solvent as necessary. The weight ratio of the solid content in the particle dispersion is appropriately set so as to obtain a desired concentration of color, but about 0.1 to 25% by weight is appropriate. These components are added to a nonpolar solvent and mixed and dispersed to obtain a particle dispersion. In this case, a known dispersing means such as a homogenizer, a ball mill, a sand mill, or an attritor may be used as the dispersing means.

本発明の第7の実施の形態を図2に基づき説明する。
図2において、(5)および(6)は導電層で少なくとも一方は光透過性である。導電層としてはAl、Ag、Ni、Cu等の金属やITO、SnO、ZnO:Al等の透明導電体をスパッタリング法、真空蒸着法、CVD法、塗布法等で薄膜状に形成したもの、あるいは導電剤を溶媒あるいは合成樹脂バインダに混合して塗布したものが用いられる。導電剤としてはポリメチルベンジルトリメチルクロライド、ポリアリルポリメチルアンモニウムクロライド等のカチオン性高分子電解質、ポリスチレンスルホン酸塩、ポリアクリル酸塩等のアニオン性高分子電解質や電子伝導性の酸化亜鉛、酸化スズ、酸化インジウム微粉末等が用いられる。導電層は自体が自己保持機能を有する程度に厚い場合もあるし、図示しない自己保持機能を有する基体上に導電層が設けられている場合もあり、いずれの場合も好適に使用できる。また、導電層(5)、(6)は、異方導電性を示す層であってもよいし、厚さ方向に導電性部分が貫通したパターン状ないしマルチドット状のセグメントを有する層であってもよい。いずれにおいても導電層(5)、(6)の一部に電源電極をコンタクトすれば導電層(5)、(6)の間に電界を生じさせることが可能となるので、白色ないし着色粒子は確実に移動できる。表示を行なうには導電層(5)、(6)間の電圧印加手段を用意すればよいので、簡便である。
A seventh embodiment of the present invention will be described with reference to FIG.
In FIG. 2, (5) and (6) are conductive layers, at least one of which is light transmissive. As the conductive layer, a metal such as Al, Ag, Ni, Cu or the like, or a transparent conductor such as ITO, SnO 2 , ZnO: Al or the like formed into a thin film by a sputtering method, a vacuum deposition method, a CVD method, a coating method, Or what mixed and apply | coated the electrically conductive agent with the solvent or the synthetic resin binder is used. Conductive agents include cationic polyelectrolytes such as polymethylbenzyltrimethyl chloride and polyallylpolymethylammonium chloride, anionic polyelectrolytes such as polystyrene sulfonate and polyacrylate, and electronically conductive zinc oxide and tin oxide. Indium oxide fine powder or the like is used. The conductive layer itself may be thick enough to have a self-holding function, or the conductive layer may be provided on a substrate having a self-holding function (not shown), which can be preferably used in either case. In addition, the conductive layers (5) and (6) may be layers having anisotropic conductivity, or layers having pattern-like or multi-dot segments with conductive portions penetrating in the thickness direction. May be. In any case, if the power supply electrode is contacted to a part of the conductive layers (5) and (6), an electric field can be generated between the conductive layers (5) and (6). Can move reliably. In order to perform the display, voltage applying means between the conductive layers (5) and (6) may be prepared, which is convenient.

図2において、(7)はマイクロカプセルである。ただし、マイクロカプセルは必須用件ではなくフォトリソグラフィーなどにより微細な隔壁を設けたセル内に後述の粒子分散液を封入しても良い。いずれにせよ2つの電極間を微細な多数のセルで区切った方が重力による粒子の偏りや粒子同士の凝集を防ぐことができるので好ましい。マイクロカプセルの作製方法としては、コアセルベーション法、相分離法など公知の方法が使用でき、特に限定されない。(8)は精製された白色粒子である。粒子分散液における固形分の重量割合は、所望の濃度の色が得られるように適宜設定されるが、0.1〜25重量%程度が適当である。これら各成分を非極性溶媒中に加え混合分散することにより粒子分散液を得る。この場合、分散手段としてホモジナイザー、ボールミル、サンドミル、アトライター等公知の分散手段を用いてもよい。   In FIG. 2, (7) is a microcapsule. However, the microcapsule is not an essential requirement, and a particle dispersion described later may be enclosed in a cell provided with fine partition walls by photolithography or the like. In any case, it is preferable to divide the two electrodes by a large number of fine cells because it can prevent the deviation of particles and the aggregation of particles due to gravity. A known method such as a coacervation method or a phase separation method can be used as a method for producing the microcapsules, and is not particularly limited. (8) is a purified white particle. The weight ratio of the solid content in the particle dispersion is appropriately set so as to obtain a desired concentration of color, but about 0.1 to 25% by weight is appropriate. These components are added to a nonpolar solvent and mixed and dispersed to obtain a particle dispersion. In this case, a known dispersing means such as a homogenizer, a ball mill, a sand mill, or an attritor may be used as the dispersing means.

図2において、(9)は着色分散媒であり、非極性有機溶媒が白色粒子の色とは異なる色に着色されている。着色分散媒には分散粒子の分散性を制御するために分散剤などが必要に応じて添加されることもある。
使用される染料の例としては、上記分散媒に可溶な油溶性染料が挙げられ、Colour IndexにおいてSolvent dyeに分類される染料が好適に使用される。これらの染料にはアゾ系、アントラキノン系、フタロシアニン系、トリアリルメタン系の各色の染料が存在する。これら油性染料は、例えば、スピリットブラック(SB、SSBB、AB)、ニグロシンベース(SA、SAP、SAPL、EE、EEL、EX、EXBP、EB)、オイルイエロー(105、107、129、3G、GGS)、オイルオレンジ(201、PS、PR)、ファーストオレンジ、オイルレッド(5B、RR、OG)、オイルスカーレット、オイルピンク312、オイルバイオレット#730、マクロレックスブルーRR、スミプラストグリーンG、オイルブラウン(GR、416)、スーダンブラックX60、オイルグリーン(502、BG)、オイルブルー(613、2N、BOS)、オイルブラック(HBB、860、BS)、バリファーストイエロー(1101、1105、3108、4120)、バリファーストオレンジ(3209、3210)、バリファーストレッド(1306、1355、2303、3304、3306、3320)、バリファーストピンク2310N、バリファーストブラウン(2402、3405)、バリファーストブルー(3405、1501、1603、1605、1607、2606、2610)、バリファーストバイオレット(1701、1702)、ヴァリファーストブラック(1802、1807、3804、3810、3820、3830)が代表的なものとして挙げられるが、本発明の目的に反しない限り、ここに記載された染料以外の油性染料又は油溶性染料であっても構わない。
In FIG. 2, (9) is a colored dispersion medium, and the nonpolar organic solvent is colored in a color different from the color of the white particles. In order to control the dispersibility of the dispersed particles, a dispersant or the like may be added to the colored dispersion medium as necessary.
Examples of the dye used include oil-soluble dyes that are soluble in the dispersion medium, and dyes that are classified as Solvent dye in the Color Index are preferably used. These dyes include azo dyes, anthraquinone dyes, phthalocyanine dyes, and triallylmethane dyes. These oil-based dyes include, for example, Spirit Black (SB, SSBB, AB), Nigrosine Base (SA, SAP, SAPL, EE, EEL, EX, EXBP, EB), Oil Yellow (105, 107, 129, 3G, GGS) , Oil orange (201, PS, PR), Fast orange, Oil red (5B, RR, OG), Oil scarlet, Oil pink 312, Oil violet # 730, Macrolex blue RR, Sumiplast green G, Oil brown (GR 416), Sudan Black X60, Oil Green (502, BG), Oil Blue (613, 2N, BOS), Oil Black (HBB, 860, BS), Bali First Yellow (1101, 1105, 3108, 4120), Bali First ole Di (3209, 3210), Bali First Red (1306, 1355, 2303, 3304, 3306, 3320), Bali First Pink 2310N, Bali First Brown (2402, 3405), Bali First Blue (3405, 1501, 1603, 1605, 1607, 2606, 2610), Bali First Violet (1701, 1702), Vari First Black (1802, 1807, 3804, 3810, 3820, 3830) are typical examples, as long as they are not contrary to the object of the present invention. Oil-based dyes or oil-soluble dyes other than the dyes described herein may be used.

図2において、(10)は接着支持層であり、マイクロカプセルを導電層(5)、(6)間に保持する。接着支持層(10)には導電層に接着する任意の公知の材料が使用できるが、透明であること、また電気的絶縁性に優れることが好ましい。特に無溶剤型の硬化材料が好ましい。このような材料としては光硬化型のエポキシ樹脂、ウレタン樹脂、アクリル樹脂が挙げられる。   In FIG. 2, (10) is an adhesive support layer, which holds the microcapsules between the conductive layers (5) and (6). Although any known material that adheres to the conductive layer can be used for the adhesive support layer (10), it is preferably transparent and excellent in electrical insulation. A solvent-free curable material is particularly preferable. Examples of such a material include a photocurable epoxy resin, a urethane resin, and an acrylic resin.

別の本発明の第7の実施の形態を図3に基づき説明する。
図3において、(8A)、(8B)は精製された白色ないし着色粒子であり、(8A)、(8B)の色および帯電極性はそれぞれ異なる。図3において、(11)は分散媒であり、無色透明であることが白色ないし着色粒子(8A)、(8B)の色の違いに基づく画像のコントラストに悪影響を与えないので好ましい。分散媒(11)には分散粒子の分散性を制御するために分散剤などが必要に応じて添加されることもある。粒子分散液を構成する白色粒子の例としては、前記白色粒子が挙げられる。着色粒子の例としては、公知の白色以外の電気泳動粒子が挙げられる。図3において(5)および(6)は導電層で少なくとも一方は光透過性である。導電層としては前記の材料が使用できる。導電層(5)、(6)の一部に電源電極をコンタクトすれば導電層(5)、(6)の間に電界を生じさせることが可能となり、2種の粒子(8A)、(8B)は確実にかつそれぞれ逆方向に移動できる。表示を行なうには導電層(5)、(6)間の電圧印加手段を用意すればよいので、簡便である。
Another seventh embodiment of the present invention will be described with reference to FIG.
In FIG. 3, (8A) and (8B) are purified white or colored particles, and (8A) and (8B) have different colors and charged polarities. In FIG. 3, (11) is a dispersion medium, and being colorless and transparent is preferable because it does not adversely affect the contrast of the image based on the color difference between white or colored particles (8A) and (8B). In order to control the dispersibility of the dispersed particles, a dispersant or the like may be added to the dispersion medium (11) as necessary. Examples of white particles constituting the particle dispersion include the white particles. Examples of the colored particles include known electrophoretic particles other than white. In FIG. 3, (5) and (6) are conductive layers, at least one of which is light transmissive. The above materials can be used for the conductive layer. An electric field can be generated between the conductive layers (5) and (6) by contacting the power supply electrode with a part of the conductive layers (5) and (6), and the two kinds of particles (8A) and (8B) ) Can move reliably and in the opposite directions. In order to perform the display, voltage applying means between the conductive layers (5) and (6) may be prepared, which is convenient.

本実施の形態における画像表示媒体を製造するには、上記で得られる粒子分散液含有マイクロカプセルと接着支持層となる接着剤とを混合した混合物を電極基板に塗布し、対向電極基板を張り合わせる。塗布方法としてはブレード、ワイヤーバー、ディッピング、スピンコートなど公知の塗膜形成方法が使用でき、また特に限定されない。これらの工程により簡便に画像表示媒体を製造することが可能となる。   In order to manufacture the image display medium in the present embodiment, a mixture obtained by mixing the particle dispersion-containing microcapsules obtained above and an adhesive serving as an adhesive support layer is applied to an electrode substrate, and the counter electrode substrate is bonded to the electrode substrate. . As a coating method, a known coating film forming method such as blade, wire bar, dipping, spin coating or the like can be used, and it is not particularly limited. An image display medium can be easily manufactured by these steps.

本発明の第8の実施の形態を図4に基づき説明する。
図4に示されるように、本発明の画像表示装置(12)は画像表示媒体(13)を備え、そして、図示しない駆動回路、演算回路、内部メモリ、電源等を備えている。表示媒体における電極は、ドットマトリックスを形成し、指定のドットをON表示することにより、全体として画像を表示する。図4において、(14)は筺体であり、また、(15)は情報入力手段である。
An eighth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 4, the image display device (12) of the present invention includes an image display medium (13), and includes a drive circuit, an arithmetic circuit, an internal memory, a power source and the like (not shown). The electrodes in the display medium form a dot matrix and display an image as a whole by displaying ON a specified dot. In FIG. 4, (14) is a housing, and (15) is information input means.

本発明を実施例によりさらに詳細に説明する。ただし、本発明は下記の実施例に限定されるものではない。なお、以下の実施例で用いる部は、全て重量部である。
実施例1
(電気泳動粒子の精製)
油溶性顔料分散剤(アビシア Solsperse 17000)0.1部をイソパラフィン系炭化水素溶媒(エクソン化学 Isopar H)100部に溶解した分散媒に酸化チタン(石原産業 TIPAQUE CR−90 平均一次粒径280nm)1部を分散した。この分散液を容器に入れ、金属電極2枚を1mm間隔で対向するように浸漬し、両電極間に50Vの直流電圧を10分間印加した。電圧印加終了後、一方の電極に電着した酸化チタンを溶媒で洗い落とし、遠心分離を3回繰り返して乾燥し、精製粒子を得た。
The invention is explained in more detail by means of examples. However, the present invention is not limited to the following examples. The parts used in the following examples are all parts by weight.
Example 1
(Purification of electrophoretic particles)
Titanium oxide (Ishihara Sangyo TIPAQUE CR-90 average primary particle size 280 nm) 1 in a dispersion medium in which 0.1 part of an oil-soluble pigment dispersant (Avicia Solsperse 17000) is dissolved in 100 parts of an isoparaffin hydrocarbon solvent (Exxon Chemical Isopar H) Parts were dispersed. This dispersion was put in a container, and two metal electrodes were immersed so as to face each other at 1 mm intervals, and a DC voltage of 50 V was applied between both electrodes for 10 minutes. After the voltage application was completed, the titanium oxide electrodeposited on one electrode was washed off with a solvent and centrifuged three times to dry, thereby obtaining purified particles.

(画像表示媒体の作製と動作)
水290部に尿素10部、レソルシノール1部、エチレン−無水マレイン酸共重合体10部を溶解したものを水酸化ナトリウム水溶液でpHを3.5に調整した。別にイソパラフィン系炭化水素溶媒(エクソン化学 Isopar H)の染料(バイエル マクロレックスブルーRR)飽和溶液30部に上記微粒子6部およびオクタン酸酸化ジルコニウム0.03部を加え超音波分散したものを粒子分散液として調製し、この分散液を上記水溶液に加え、さらにホルムアルデヒド溶液25部を加えて50℃で3時間加熱撹拌した。反応終了後吸引ろ過と水洗、乾燥によりマイクロカプセルを回収した。
上記で得られたマイクロカプセルを紫外線硬化エポキシ樹脂(商品名:スリーボンド 3121)中に分散させ、ITO電極付きガラス基板上にワイヤーバーで塗布した。次にもう一枚のITO電極で電極間が100μmになるように塗布膜を挟み、その後紫外線を照射し硬化させた。
上部ITO電極に−100Vを印加すると、白色微粒子は速やかに上部電極側に電着し、上部基板面から見ると白色に見えた。次に上部電極に+100Vを印加すると、白色微粒子は下部電極側に移動し、上部基板側から見ると染料の色に起因する着色状態が鮮明に見られた。また白色表示時の白色反射率(白色入射光量に対する反射光量の割合)は35%であった。
(Production and operation of image display medium)
A solution prepared by dissolving 10 parts of urea, 1 part of resorcinol and 10 parts of ethylene-maleic anhydride copolymer in 290 parts of water was adjusted to pH 3.5 with an aqueous sodium hydroxide solution. Separately, 30 parts of an isoparaffin hydrocarbon solvent (Exxon Chemical Isopar H) dye (Bayer Macrolex Blue RR) saturated solution and ultrasonically dispersed with 6 parts of the fine particles and 0.03 part of zirconium octoate are dispersed into particles. The dispersion was added to the aqueous solution, and 25 parts of a formaldehyde solution was further added, followed by heating and stirring at 50 ° C. for 3 hours. After completion of the reaction, the microcapsules were collected by suction filtration, washing with water and drying.
The microcapsules obtained above were dispersed in an ultraviolet curable epoxy resin (trade name: ThreeBond 3121) and applied on a glass substrate with an ITO electrode with a wire bar. Next, the coating film was sandwiched with another ITO electrode so that the distance between the electrodes was 100 μm, and then cured by irradiation with ultraviolet rays.
When −100 V was applied to the upper ITO electrode, the white fine particles were quickly electrodeposited on the upper electrode side, and looked white when viewed from the upper substrate surface. Next, when +100 V was applied to the upper electrode, the white fine particles moved to the lower electrode side, and when viewed from the upper substrate side, the coloring state due to the color of the dye was clearly seen. The white reflectance during white display (the ratio of the reflected light amount to the white incident light amount) was 35%.

比較例1
(画像表示媒体の作製と動作)
白色泳動粒子として精製操作を行わなかった酸化チタンを使用した以外は実施例1と同様に画像表示媒体を作製し電圧を印加させて表示切替を行なったところ、白色表示時の白色反射率はほぼ同等であったが染料の色に起因する着色状態は逆極性に泳動する酸化チタンに起因して鮮明ではなかった。
Comparative Example 1
(Production and operation of image display medium)
An image display medium was prepared in the same manner as in Example 1 except that titanium oxide that had not been subjected to a purification operation was used as white migrating particles, and the display was switched by applying a voltage. The coloration due to the color of the dye was equivalent but was not clear due to the titanium oxide migrating to the opposite polarity.

実施例2
(電気泳動粒子の精製)
黒色粒子としてカーボンブラック(三菱化学 MA100 平均径1μm)0.2部とポリエチレン0.8部を加熱により溶融混練し微粉砕したものをシリコーンオイル(信越化学 KF96L−1cs)100部に分散した分散液を容器に入れ、金属電極2枚を1mm間隔で対向するように浸漬し、両電極間に50Vの直流電圧を10分間印加した。電圧印加終了後、電圧の極性を反転させて再度両電極間に50Vの直流電圧を10分間印加した。電圧印加終了後、大量の黒色粒子が電着した一方の電極を新たなシリコーンオイル100部に浸漬し、5分間超音波振動を加えた。得られた粒子分散液に対して上記の操作をもう一度繰り返し、最後は遠心分離と乾燥により黒色粒子を回収した。
Example 2
(Purification of electrophoretic particles)
Dispersion liquid in which 0.2 parts of carbon black (Mitsubishi Chemical MA100 average diameter 1 μm) and 0.8 parts of polyethylene were melt-kneaded by heating and finely pulverized as black particles in 100 parts of silicone oil (Shin-Etsu Chemical KF96L-1cs) Was immersed in two metal electrodes facing each other at 1 mm intervals, and a DC voltage of 50 V was applied between both electrodes for 10 minutes. After the voltage application was completed, the polarity of the voltage was reversed and a DC voltage of 50 V was applied again between the electrodes for 10 minutes. After the voltage application was completed, one electrode electrodeposited with a large amount of black particles was immersed in 100 parts of new silicone oil and subjected to ultrasonic vibration for 5 minutes. The above operation was repeated once again on the obtained particle dispersion, and finally black particles were collected by centrifugation and drying.

(画像表示媒体の作製と動作)
上記黒色粒子1部と実施例1で精製した白色粒子6部をシリコーンオイル30部に加えて超音波分散したものを粒子分散液として調製した以外は実施例1と同様に画像表示媒体を作製した。
この画像表示媒体の上部ITO電極に−100Vを印加すると、白色微粒子は速やかに上部電極側に電着し、一方黒色粒子は下部電極側に移動し、上部基板面から見ると白色に見えた。次に上部電極に+100Vを印加すると、白色微粒子は下部電極側に移動し、一方黒色粒子は上部電極側に移動し、上部基板側から見ると黒色に見えた。また白色表示時の白色反射率は40%であった。
(Production and operation of image display medium)
An image display medium was prepared in the same manner as in Example 1 except that 1 part of the black particles and 6 parts of white particles purified in Example 1 were added to 30 parts of silicone oil and ultrasonically dispersed. .
When -100 V was applied to the upper ITO electrode of this image display medium, the white fine particles were quickly electrodeposited on the upper electrode side, while the black particles moved to the lower electrode side and looked white when viewed from the upper substrate surface. Next, when +100 V was applied to the upper electrode, the white fine particles moved to the lower electrode side, while the black particles moved to the upper electrode side, and looked black when viewed from the upper substrate side. The white reflectance during white display was 40%.

比較例2
(画像表示媒体の作製と動作)
白色粒子と黒色粒子として精製操作を行なわなかったものを使用した以外は実施例2と同様に画像表示媒体を作製し電圧を印加させて表示切替を行なったところ、白色反射率は25%であり明らかに白色度が低かった。
Comparative Example 2
(Production and operation of image display medium)
An image display medium was prepared in the same manner as in Example 2 except that white particles and black particles that were not refined were used, and the display was switched by applying a voltage. The white reflectance was 25%. The whiteness was clearly low.

本発明の一実施の形態である電気泳動粒子の精製方法を具現化する装置の模式図である。It is a schematic diagram of the apparatus which embodies the purification method of the electrophoretic particle which is one embodiment of the present invention. 本発明の一実施の形態を示す画像表示媒体の断面図である。It is sectional drawing of the image display medium which shows one embodiment of this invention. 本発明の他の一実施の形態を示す画像表示媒体の断面図である。It is sectional drawing of the image display medium which shows other one Embodiment of this invention. 本発明の一実施の形態を示す画像表示装置の模式図である。It is a schematic diagram of an image display device showing an embodiment of the present invention.

符号の説明Explanation of symbols

1 容器
2 粒子分散液
3A、3B 電極
4 電源
5 導電層
6 導電層
7 マイクロカプセル
8 白色粒子
8A、8B 白色ないし着色粒子
9 着色分散媒
10 接着支持層
11 分散媒
12 画像表示装置
13 画像表示媒体
14 筺体
15 情報入力手段
DESCRIPTION OF SYMBOLS 1 Container 2 Particle dispersion liquid 3A, 3B Electrode 4 Power supply 5 Conductive layer 6 Conductive layer 7 Microcapsule 8 White particle 8A, 8B White thru | or colored particle 9 Colored dispersion medium 10 Adhesive support layer 11 Dispersion medium 12 Image display apparatus 13 Image display medium 14 Housing 15 Information input means

Claims (8)

電気泳動性を有する粒子を非極性溶媒に分散させた粒子分散液に2つの電極基板を浸漬し、これら電極間に直流電圧を印加して一方の電極基板に該粒子を電着させた後、電着した粒子のみを回収することを特徴とする電気泳動粒子の精製方法。 After immersing two electrode substrates in a particle dispersion in which particles having electrophoretic properties are dispersed in a nonpolar solvent, and applying a DC voltage between these electrodes to electrodeposit the particles on one electrode substrate, A method for purifying electrophoretic particles, comprising collecting only the electrodeposited particles. 前記回収粒子をさらに非極性溶媒に再分散し、再度前記電圧印加および粒子回収の工程を複数回繰り返すことを特徴とする請求項1に記載の電気泳動粒子の精製方法。 2. The method for purifying electrophoretic particles according to claim 1, wherein the recovered particles are further redispersed in a nonpolar solvent, and the steps of applying the voltage and recovering the particles are repeated a plurality of times. 前記電圧印加を行なった後、さらに2電極間に逆極性の直流電圧を印加することを特徴とする請求項1又は2に記載の電気泳動粒子の精製方法。 The method for purifying electrophoretic particles according to claim 1, wherein after applying the voltage, a DC voltage having a reverse polarity is further applied between the two electrodes. 前記電着させた粒子を回収する際乃至非極性溶媒に再分散する際に、電極を非極性溶媒に浸漬し、超音波を印加することを特徴とする請求項1乃至3のいずれかに記載の電気泳動粒子の精製方法。 4. The electrode is immersed in a nonpolar solvent and ultrasonic waves are applied when the electrodeposited particles are collected or redispersed in a nonpolar solvent. Of purification of electrophoretic particles. 前記請求項1乃至4のいずれかに記載の精製方法により得られることを特徴とする電気泳動粒子。 Electrophoretic particles obtained by the purification method according to any one of claims 1 to 4. 少なくとも請求項5に記載の電気泳動粒子を非極性溶媒に分散させることを特徴とする電気泳動粒子分散液。 6. An electrophoretic particle dispersion, wherein at least the electrophoretic particles according to claim 5 are dispersed in a nonpolar solvent. 所望の間隔を設けて配設された少なくとも一方が光透過性である二つの基板間に、少なくとも請求項6に記載の電気泳動粒子を非極性溶媒に分散してなる分散液を含有してなり、前記二基板間に電圧を印加することによる該粒子の電気泳動により表示動作を行なうことを特徴とする画像表示媒体。 A dispersion liquid in which at least one of the electrophoretic particles according to claim 6 is dispersed in a non-polar solvent is contained between two substrates, at least one of which is disposed at a desired interval and is light transmissive. An image display medium which performs a display operation by electrophoresis of the particles by applying a voltage between the two substrates. 請求項7に記載の画像表示媒体を構成要素に有することを特徴とする画像表示装置。
An image display apparatus comprising the image display medium according to claim 7 as a component.
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US8237733B2 (en) 2009-03-31 2012-08-07 Ricoh Co., Ltd. Page transition on electronic paper display

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