【０００１】[0001]
【産業上の利用分野】本発明は、電気泳動粒子を利用し
た表示素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using electrophoretic particles.
【０００２】[0002]
【従来の技術】従来より、少なくとも一方の電極板が透
明である対向配置された一組の電極板の間に、電気泳動
粒子を着色分散媒に分散させてなる分散系を封入し、電
極板間に電圧を印加することにより電気泳動粒子を透明
電極板側へ移動させて、電気泳動粒子と分散媒とのコン
トラストを透明電極板側から認識させる電気泳動表示素
子が開発されている。2. Description of the Related Art Conventionally, a dispersion system, in which electrophoretic particles are dispersed in a coloring dispersion medium, is enclosed between a pair of opposed electrode plates in which at least one electrode plate is transparent, and the space between the electrode plates is sealed. An electrophoretic display element has been developed in which a voltage is applied to move electrophoretic particles to the transparent electrode plate side and the contrast between the electrophoretic particles and the dispersion medium is recognized from the transparent electrode plate side.
【０００３】従来の電気泳動表示素子では、分散媒中に
分散している電気泳動粒子が電極板に付着したり、ある
いは、電気泳動粒子が互いに凝集し、または電気泳動粒
子と分散媒との比重の差により時間の経過とともに電気
泳動粒子が徐々に沈降したり、あるいは、電気泳動粒子
の帯電が不十分で印加電圧に対して十分応答できないと
いう現象が生じていた。このため、信頼性が高く耐久性
のある電気泳動表示素子は実現していなかった。In the conventional electrophoretic display device, electrophoretic particles dispersed in a dispersion medium adhere to the electrode plate, or the electrophoretic particles aggregate with each other, or the specific gravity of the electrophoretic particles and the dispersion medium. Due to the difference, the electrophoretic particles gradually settled with the passage of time, or the electrophoretic particles were not sufficiently charged and could not sufficiently respond to the applied voltage. For this reason, a highly reliable and durable electrophoretic display element has not been realized.
【０００４】このような欠点を解決するために、電気泳
動粒子を樹脂で被覆することにより電気泳動粒子と分散
媒との比重を実質上等しくすることが提案されている
（特開昭４８−３１０９７号公報）。また、電気泳動粒
子としての二酸化チタン微粒子をシリコン樹脂で被覆す
ることにより、電気泳動粒子に大きな自然発生帯電量を
付与することが提案されている（特開平２−１８９５２
５号公報）。さらに、電気泳動粒子をチタネート系のカ
ップリング剤とソルビタン脂肪酸エステルで処理するこ
とが提案されている（特開平２−２８４１２８号公
報）。In order to solve such a drawback, it has been proposed to coat the electrophoretic particles with a resin so that the specific gravities of the electrophoretic particles and the dispersion medium are substantially equal (Japanese Patent Laid-Open No. 48-31097). Publication). Further, it has been proposed to coat titanium dioxide fine particles as electrophoretic particles with a silicone resin to impart a large amount of spontaneous charge to the electrophoretic particles (JP-A-2-18952).
No. 5). Further, it has been proposed to treat the electrophoretic particles with a titanate-based coupling agent and a sorbitan fatty acid ester (JP-A-2-284128).
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記の
樹脂で被覆された電気泳動粒子は、確かに比重が分散媒
と実質上等しくなり、分散媒中での電気泳動粒子の沈降
等は防止されるが、電気泳動粒子を被覆している樹脂が
分散媒中の染料等により汚染され易く、電気泳動粒子と
分散媒とのコントラストが低下してしまうという問題が
ある。さらに、加熱溶融樹脂中に電気泳動粒子を分散さ
せ、冷却硬化後に電気泳動表示素子に適した所定の大き
さに微粉砕することが困難であるという問題もある。However, the specific gravity of the above-mentioned resin-coated electrophoretic particles is substantially equal to that of the dispersion medium, and sedimentation of the electrophoretic particles in the dispersion medium is prevented. However, there is a problem that the resin coating the electrophoretic particles is easily contaminated by the dye or the like in the dispersion medium, and the contrast between the electrophoretic particles and the dispersion medium is lowered. Further, there is a problem that it is difficult to disperse the electrophoretic particles in the heat-melted resin and to finely pulverize the electrophoretic particles into a predetermined size suitable for the electrophoretic display element after cooling and curing.
【０００６】また、上記のシリコン樹脂で被覆された二
酸化チタン微粒子を電気泳動粒子として使用する場合
は、低消費電力で大型化の容易な電気泳動表示素子が可
能となるが、シリコン樹脂が分散媒中の染料等により汚
染され易く、経時的に電気泳動粒子と分散媒とのコント
ラストが低下してしまうという問題がある。When titanium dioxide fine particles coated with the above-mentioned silicon resin are used as electrophoretic particles, an electrophoretic display element that consumes less power and can easily be made larger is possible, but the silicon resin is a dispersion medium. There is a problem in that it is easily contaminated by the dyes therein and the contrast between the electrophoretic particles and the dispersion medium decreases over time.
【０００７】さらに、上記のチタネート系のカップリン
グ剤とソルビタン脂肪酸エステルで処理された電気泳動
粒子は、表面に有機単分子膜が形成され、これにより有
機分散媒との親和性が向上し、電極板への付着や粒子相
互の凝集による沈降は防止されるが、電気泳動粒子の比
重そのものは変わらない。したがって、比重の大きい無
機粒子を電気泳動粒子として使用する場合には、一般に
毒性が大きく、高価な比重の大きい分散媒を用いないと
粒子の単独沈降が発生するという問題がある。Further, the electrophoretic particles treated with the titanate-based coupling agent and the sorbitan fatty acid ester have an organic monomolecular film formed on the surface thereof, thereby improving the affinity with the organic dispersion medium, and thus the electrode. Sedimentation due to adhesion to the plate and aggregation of particles is prevented, but the specific gravity of the electrophoretic particles itself does not change. Therefore, when the inorganic particles having a large specific gravity are used as the electrophoretic particles, there is a problem that the particles are generally highly toxic and the particles are solely precipitated unless an expensive dispersion medium having a large specific gravity is used.
【０００８】本発明は、このような事情に鑑みてなされ
たものであり、電気泳動粒子の凝集、沈降、電極板への
付着等が防止された電気泳動表示用の分散系と、このよ
うな分散系を用いたメモリー性に優れ信頼性の高い電気
泳動表示素子を提供することを目的とする。The present invention has been made in view of the above circumstances, and a dispersion system for electrophoretic display in which agglomeration, sedimentation, adhesion to electrode plates, etc. of electrophoretic particles are prevented, and such a system. It is an object of the present invention to provide an electrophoretic display device that uses a dispersion system and has excellent memory properties and high reliability.
【０００９】[0009]
【課題を解決するための手段】このような目的を達成す
るために、本発明の電気泳動表示用の分散系は表面にポ
リマーのグラフト鎖が形成された電気泳動粒子と、分散
媒とからなるような構成とした。In order to achieve such an object, the dispersion system for electrophoretic display of the present invention comprises electrophoretic particles having a polymer graft chain formed on the surface and a dispersion medium. It was configured like this.
【００１０】また、本発明の電気泳動表示素子は、少な
くとも一方が透明な一組の電極板を所定の間隔を設けて
対向配置して形成した空間に上記の分散系を封入すると
ともに、前記電極板間に制御用電圧を印加して前記分散
系内の電気泳動粒子の分布状態を変えるための制御手段
を設けたような構成とした。Further, in the electrophoretic display device of the present invention, the above-mentioned dispersion system is enclosed in a space formed by facing a pair of electrode plates, at least one of which is transparent, with a predetermined gap therebetween, The control means is applied between the plates to change the distribution state of the electrophoretic particles in the dispersion system.
【００１１】[0011]
【作用】電気泳動粒子は表面にポリマーのグラフト鎖が
形成されて表面改質され、分散媒中での電気泳動粒子の
凝集、沈降、電極板への付着（固着）等が防止された電
気泳動表示用の分散系が得られ、このような分散系が少
なくとも一方が透明な一組の電極板を所定の間隔を設け
て対向配置して形成した空間に封入され、制御手段によ
り電極板間に制御用電圧が印加されることにより表示動
作が行われる。[Function] The electrophoretic particles are surface-modified by forming polymer graft chains on the surface to prevent the electrophoretic particles from aggregating, settling, and adhering (fixing) to the electrode plate in the dispersion medium. A dispersion system for display is obtained, and such a dispersion system is enclosed in a space formed by opposing a pair of transparent electrode plates, at least one of which is transparent, with a control means between the electrode plates. The display operation is performed by applying the control voltage.
【００１２】[0012]
【実施例】以下、本発明の一実施例について図面を参照
しながら説明する。図１は本発明の電気泳動表示素子の
構成を示す概略断面図である。図１において、電気泳動
表示素子１は、表面に透明電極３が設けられた透明基板
２と、表面に複数の分割電極５が設けられた基板４と
を、透明電極３と分割電極５とが対向するように配置
し、この両電極間の周縁部分にスペーサ６を介在させる
ことにより密封空間７を形成し、この密封空間７に電気
泳動表示用の分散系１１を封入したものである。そし
て、複数の分割電極５のうちの所望の電極に制御用電圧
を付加して透明電極３と分割電極５との間に電界を形成
し分散系１１内の電気泳動粒子の分布状態を変えるため
の制御手段（図示せず）が配設されている。また、分散
系１１は、着色分散媒１２と、この着色分散媒１２中に
分散されている電気泳動粒子１３とからなっている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing the structure of the electrophoretic display device of the present invention. In FIG. 1, the electrophoretic display element 1 includes a transparent substrate 2 having a transparent electrode 3 provided on the surface thereof and a substrate 4 having a plurality of divided electrodes 5 provided on the surface thereof. It is arranged so as to face each other, and a sealed space 7 is formed by interposing a spacer 6 in a peripheral portion between both electrodes, and a dispersion system 11 for electrophoretic display is enclosed in the sealed space 7. Then, a control voltage is applied to a desired electrode among the plurality of divided electrodes 5 to form an electric field between the transparent electrode 3 and the divided electrode 5 to change the distribution state of the electrophoretic particles in the dispersion system 11. Control means (not shown) is provided. The dispersion system 11 includes a colored dispersion medium 12 and electrophoretic particles 13 dispersed in the colored dispersion medium 12.
【００１３】図示例では、中央より左側の分割電極に正
の制御用電圧が付加され、この領域では電気泳動粒子１
３（この場合、正に帯電しているものとする）が透明電
極３へ泳動して、透明基板２、透明電極３を介して電気
泳動粒子１３の色（例えば白色）が認識される。また、
中央より右側の分割電極には負の制御用電圧が付加さ
れ、この領域では電気泳動粒子１３が分割電極３へ泳動
して、透明基板２、透明電極３側からは着色分散媒１２
の色（例えば黒色）のみが認識される。In the illustrated example, a positive control voltage is applied to the divided electrodes on the left side of the center, and in this region, the electrophoretic particles 1
3 (in this case, positively charged) migrates to the transparent electrode 3, and the color (for example, white) of the electrophoretic particles 13 is recognized through the transparent substrate 2 and the transparent electrode 3. Also,
A negative control voltage is applied to the divided electrodes on the right side of the center, and in this region, the electrophoretic particles 13 migrate to the divided electrodes 3 and the colored dispersion medium 12 is applied from the transparent substrate 2 and transparent electrode 3 sides.
Is recognized (for example, black) only.
【００１４】透明基板２としては、ガラス基板、透明樹
脂基板（フィルム状のものも含まれる）等の公知の材料
を用いることができる。また、透明電極３は、酸化イン
ジウムスズ（ＩＴＯ）、酸化スズ（ＳｎＯ2）、酸化イ
ンジウム、ヨウ化銅の薄膜や金、クロムなどの金属蒸着
膜等により形成することができる。As the transparent substrate 2, known materials such as a glass substrate and a transparent resin substrate (including a film-shaped substrate) can be used. Further, the transparent electrode 3 can be formed by a thin film of indium tin oxide (ITO), tin oxide (SnO2 ), indium oxide, copper iodide, a metal vapor deposition film of gold, chromium or the like.
【００１５】一方、基板４は特に限定はない。また、こ
の基板４表面に形成される分割電極５の形状、寸法等
は、電気泳動表示素子の使用目的等に応じて適宜決定す
ることができる。On the other hand, the substrate 4 is not particularly limited. Further, the shape, size and the like of the divided electrode 5 formed on the surface of the substrate 4 can be appropriately determined according to the purpose of use of the electrophoretic display element and the like.
【００１６】このような電気泳動表示素子に用いる分散
系１１を構成する着色分散媒１２は、トルエン、キシレ
ン、シクロヘキサン、ｎ−ヘプタン、ベンゼン、ｎ−ブ
タノール、塩化エチレン、塩化メチレン、三塩化フッ化
メタン、三塩化三フッ化エタン、四塩化炭素、四塩化二
フッ化エタン、オレイン酸、シリコン油、オリーブ油、
やし油、ひまし油、流動パラフィン、アルコール系溶
媒、エステル類、脂肪族炭化水素、脂環式炭化水素、芳
香族炭化水素、ハロゲン化炭化水素等の有機溶媒、ある
いはこれらの任意の混合物からなる有機溶媒を染料で着
色したものが用いられる。The colored dispersion medium 12 constituting the dispersion system 11 used in such an electrophoretic display device is toluene, xylene, cyclohexane, n-heptane, benzene, n-butanol, ethylene chloride, methylene chloride, trifluorofluoride. Methane, trichloroethane trifluoride, carbon tetrachloride, tetrachlorodifluoroethane, oleic acid, silicone oil, olive oil,
Organic oils such as coconut oil, castor oil, liquid paraffin, alcoholic solvents, esters, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, etc., or any mixture thereof A solvent colored with a dye is used.
【００１７】本発明で用いられる電気泳動粒子１３は、
表面にポリマーのグラフト鎖が形成された電気泳動粒子
である。電気泳動粒子としては、二酸化チタン、酸化亜
鉛、硫化亜鉛、鉛白、黄鉛、硫化カドミウム、黒鉛、カ
ーボンブラック等の表面に水酸基を有する無機粉体が好
ましく用いられる。このような無機粉体の大きさは、
０．２〜２．０μｍ程度が好ましい。The electrophoretic particles 13 used in the present invention are:
It is an electrophoretic particle having a polymer graft chain formed on the surface. As the electrophoretic particles, inorganic powders having a hydroxyl group on the surface such as titanium dioxide, zinc oxide, zinc sulfide, lead white, yellow lead, cadmium sulfide, graphite and carbon black are preferably used. The size of such an inorganic powder is
It is preferably about 0.2 to 2.0 μm.
【００１８】そして、このような電気泳動粒子の表面へ
のポリマーのグラフト鎖形成は、電気泳動粒子の表面に
官能基を導入し、この官能基にポリマーをグラフト反応
させることにより行われる。導入される官能基として
は、後にグラフト重合されるポリマーとの適性を考慮し
て決定することができ、例えば下記の官能基を挙げるこ
とができる。The formation of a polymer graft chain on the surface of the electrophoretic particle is carried out by introducing a functional group into the surface of the electrophoretic particle and causing a graft reaction of the polymer with the functional group. The functional group to be introduced can be determined in consideration of suitability for a polymer to be graft-polymerized later, and the following functional groups can be exemplified.
【００１９】[0019]
【化１】[Chemical 1]
【００２０】[0020]
【化２】[Chemical 2]
【００２１】[0021]
【化３】このような官能基を電気泳動粒子の表面に導入するに
は、官能基を末端に備えた末端反応型カップリング剤に
より電気泳動粒子を処理することが好ましい。また、電
気泳動粒子の表面に導入された官能基と容易に反応して
グラフト鎖を形成するためのポリマーは、末端反応型の
変性ポリマーであることが好ましい。この場合、末端反
応型カップリング剤は電気泳動粒子に対して０．５〜１
０重量％添加することが好ましい。また、変性ポリマー
は溶剤を用いない場合、電気泳動粒子に対して大過剰に
添加することが好ましく、例えば５００〜１０００重量
％添加することができる。[Chemical 3] In order to introduce such a functional group onto the surface of the electrophoretic particle, it is preferable to treat the electrophoretic particle with an end reaction type coupling agent having a functional group at the end. The polymer for easily reacting with the functional group introduced on the surface of the electrophoretic particles to form a graft chain is preferably a terminal-reactive modified polymer. In this case, the end-reactive coupling agent is 0.5 to 1 with respect to the electrophoretic particles.
It is preferable to add 0% by weight. When the solvent is not used, the modified polymer is preferably added in a large excess with respect to the electrophoretic particles, for example, 500 to 1000% by weight can be added.
【００２２】例えば、官能基としてエポキシ基を導入す
る場合、電気泳動粒子と末端エポキシ変性のシランカッ
プリング剤とを有機溶媒中で反応させて、電気泳動粒子
表面の水酸基存在部位にエポキシ基を導入することがで
きる。そして、有機溶媒とシランカップリング剤とを取
り除いた後、エポキシ基との反応性が高いアミノ基を両
末端に有するアミノ変性ポリマーを添加して反応させる
ことによりポリマーのグラフト鎖が形成される。末端エ
ポキシ変性のシランカップリング剤としては、例えばγ
−グリシドキシプロピルトリメトキシシラン、β−
（３，４エポキシシクロヘキシル）エチルトリメトキシ
シラン、γ−グリシドキシプロピルトリメトキシシラン
等を使用することができる。また、アミノ変性ポリマー
としては、例えばアミノ変性ポリシロキサン、ポリビニ
ルアミン、ポリアリルアミン、ポリエチレンイミンなど
の他、アミノ基を有する各種マクロモノマーを使用する
ことができる。尚、上記の有機溶媒として分散系を構成
する分散媒と同一の溶媒を用いることにより、ポリマー
のグラフト鎖形成と、分散系の調製とを一連の連続操作
とすることができるので便利である。For example, when an epoxy group is introduced as a functional group, the electrophoretic particles are reacted with a terminal epoxy-modified silane coupling agent in an organic solvent to introduce an epoxy group into the hydroxyl group-existing site on the surface of the electrophoretic particles. can do. Then, after removing the organic solvent and the silane coupling agent, a graft chain of the polymer is formed by adding and reacting an amino-modified polymer having amino groups having high reactivity with an epoxy group at both ends. Examples of the terminal epoxy-modified silane coupling agent include γ
-Glycidoxypropyltrimethoxysilane, β-
(3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane and the like can be used. As the amino-modified polymer, for example, amino-modified polysiloxane, polyvinylamine, polyallylamine, polyethyleneimine, and various macromonomers having an amino group can be used. By using the same solvent as the dispersion medium constituting the dispersion system as the organic solvent, it is convenient because the graft chain formation of the polymer and the preparation of the dispersion system can be performed in a series of continuous operations.
【００２３】上述のように、電気泳動粒子１３は、表面
にポリマーのグラフト鎖が形成されたものでため、電気
泳動粒子１３の表面に位置する水酸基がブロックされて
電気泳動粒子１３の親油性が向上し、分散媒中での電気
泳動粒子１３の凝集および電極への付着が防止されると
ともに、電気泳動粒子１３の見掛の比重が低下して分散
媒中での電気泳動粒子１３の沈降が防止される。As described above, since the electrophoretic particles 13 have polymer graft chains formed on their surfaces, the hydroxyl groups located on the surfaces of the electrophoretic particles 13 are blocked, and the electrophoretic particles 13 have a lipophilic property. As a result, the aggregation of the electrophoretic particles 13 in the dispersion medium and the adhesion to the electrodes are prevented, and the apparent specific gravity of the electrophoretic particles 13 is reduced to prevent the sedimentation of the electrophoretic particles 13 in the dispersion medium. To be prevented.
【００２４】次に、実験例を示して本発明を更に詳細に
説明する。 （実験例１）冷却管を取付けた１００mlのなす型フラス
コに、充分に乾燥させた電気泳動粒子（二酸化チタン）
３ｇと、脱水洗浄したトルエン５０mlと、エポキシ変性
カップリング剤（γ−グリシドキシプロピルトリメトキ
シシラン）０．３ｇとを添加し、１２０℃に加熱して十
分に分散処理を行いながら９時間反応を行った。反応終
了後、放冷してフラスコの内容物を冷却し、その後、ト
ルエンを取り除いた。Next, the present invention will be described in more detail with reference to experimental examples. (Experimental Example 1) Electrophoretic particles (titanium dioxide) that had been sufficiently dried were placed in a 100 ml eggplant-shaped flask equipped with a cooling tube.
3 g, 50 ml of dehydrated and washed toluene, and 0.3 g of an epoxy-modified coupling agent (γ-glycidoxypropyltrimethoxysilane) were added, and the mixture was heated to 120 ° C. and sufficiently dispersed for reaction for 9 hours. I went. After completion of the reaction, the contents of the flask were cooled by allowing to cool, and then toluene was removed.
【００２５】次に、充分に乾燥させたポリマー（末端ア
ミノ変性ポリシロキサン）３０ml（二酸化チタンに対し
て１０００重量％、但し、二酸化チタンと実際に反応し
ているポリマーは二酸化チタンに対して８０重量％程
度）を上記のなす型フラスコ内に添加し、７０℃に加熱
して２時間反応を行った。以上の反応によりポリマー
（ポリシロキサン）のグラフト鎖が形成された電気泳動
粒子（本発明）を得た。Next, 30 ml of sufficiently dried polymer (terminal amino-modified polysiloxane) (1000% by weight with respect to titanium dioxide, except that the polymer actually reacting with titanium dioxide is 80% by weight with respect to titanium dioxide) %) Was added to the above eggplant-shaped flask, heated to 70 ° C. and reacted for 2 hours. By the above reaction, electrophoretic particles (invention) in which a polymer (polysiloxane) graft chain was formed were obtained.
【００２６】次に、上記のようにして調製した本発明の
電気泳動粒子と、未処理の電気泳動粒子とについて、以
下のようにして分散安定性を比較した。試験管中に被検
体である電気泳動粒子を３ｇと、分散媒（トルエン）５
０mlと、必要ならば界面活性剤（ポリカルボン酸誘導
体）０．６ｇとを添加し、マグネチックスターラで２時
間攪拌した後、直ちに上澄みを1.0 ml量り取り、これを
オーブンで加熱して分散媒を完全に除去した後の重量を
測定した。このときの重量をＷo (g) とした。また、上
記の試験管を所定時間静置した後、同様に上澄みを1.0
ml量り取り、これをオーブンで加熱して分散媒を完全に
除去した後の重量を測定した。このときの重量をＷi
(g) とした。そして、下記の式により分散安定性Ｓを算
出した。Next, the electrophoretic particles of the present invention prepared as described above and untreated electrophoretic particles were compared in dispersion stability as follows. In a test tube, 3 g of the electrophoretic particles, which is the sample, and a dispersion medium (toluene) 5
0 ml and, if necessary, a surfactant (polycarboxylic acid derivative) 0.6 g were added, stirred for 2 hours with a magnetic stirrer, and immediately 1.0 ml of the supernatant was weighed and heated in an oven to disperse the dispersion medium. Was completely removed and the weight was measured. The weight at this time was defined as Wo (g). In addition, after leaving the above test tube for a predetermined time, the supernatant was similarly removed with 1.0
ml was weighed and heated in an oven to completely remove the dispersion medium, and the weight was measured. The weight at this time is Wi
(g) Then, the dispersion stability S was calculated by the following formula.
【００２７】分散安定性Ｓ（％） ＝ Ｗi (g) ／Ｗo
(g) × １００ このようにして求めた本発明の電気泳動粒子と、未処理
の電気泳動粒子の分散安定性Ｓの測定結果を図２に示し
た。Dispersion stability S (%) = Wi (g) / Wo
(g) × 100 The measurement results of the dispersion stability S of the electrophoretic particles of the present invention thus obtained and untreated electrophoretic particles are shown in FIG.
【００２８】図２から明らかなように、未処理の電気泳
動粒子に比べて、ポリマー（ポリシロキサン）のグラフ
ト鎖が形成された電気泳動粒子は分散媒中での分散安定
性が著しく向上した。また、界面活性剤が存在すること
により分散安定性はさらに向上することが認められた。 （実験例２）比較として以下のような表面処理を行って
電気泳動粒子（比較試料１）を得た。すなわち、ポリエ
チレン樹脂７５．０７７４ｇを加熱溶融した中に二酸化
チタン粉末２４．９２２６ｇをロールミルを用いて均一
に分散した後に、冷却硬化させて微粉砕した。As is clear from FIG. 2, the electrophoretic particles having the graft chains of the polymer (polysiloxane) have remarkably improved dispersion stability in the dispersion medium, as compared with the untreated electrophoretic particles. It was also found that the dispersion stability was further improved by the presence of the surfactant. (Experimental Example 2) As a comparison, the following surface treatment was performed to obtain electrophoretic particles (Comparative Sample 1). That is, 25.9226 g of titanium dioxide powder was uniformly dispersed using a roll mill while 75.0774 g of polyethylene resin was melted by heating, followed by cooling and hardening to finely pulverize.
【００２９】次に、実験例１において作成した電気泳動
粒子（本発明）、電気泳動粒子（比較試料１）および未
処理の電気泳動粒子のそれぞれについて、下記の組成の
分散系を調製した。 （分散系の組成） 電気泳動粒子 １ 重量部 分散媒（トルエン） 3.4 重量部 染料（青色染料ＤＨ−Ｃ２（ＩＣＩ製）） 0.04重量部 界面活性剤（ポリカルボン酸誘導体） 0.2 重量部 そして、上記の分散系を図１に示されるような電気泳動
表示素子の密封空間に封入して電気泳動表示素子とし
た。この電気泳動表示素子の透明電極と分割電極間に３
０Ｖの電圧を印加して表示性を比較した。さらに、１４
日間経過後に同じように表示性を比較した。Next, a dispersion system having the following composition was prepared for each of the electrophoretic particles (invention), the electrophoretic particles (comparative sample 1) and the untreated electrophoretic particles prepared in Experimental Example 1. (Composition of dispersion system) Electrophoretic particles 1 part by weight Dispersion medium (toluene) 3.4 parts by weight Dye (blue dye DH-C2 (manufactured by ICI)) 0.04 parts by weight Surfactant (polycarboxylic acid derivative) 0.2 parts by weight And the above The dispersion system of No. 1 was sealed in the sealed space of the electrophoretic display device as shown in FIG. Between the transparent electrode and the divided electrode of this electrophoretic display element, 3
A display voltage was compared by applying a voltage of 0V. Furthermore, 14
The display properties were similarly compared after the lapse of days.
【００３０】その結果、電気泳動粒子（本発明）を用い
た電気泳動表示素子では、メモリー性に著しい向上がみ
られ、電気泳動粒子の沈降、電極への付着は防止され表
示性の優れた電気泳動表示素子であった。また、経時に
よる表示性の低下はみられなかった。As a result, in the electrophoretic display device using the electrophoretic particles (the present invention), the memory property is remarkably improved, and the electrophoretic particles are prevented from settling and adhering to the electrodes, and thus the electrophoretic display device having excellent display properties is obtained. It was a migration display element. In addition, the displayability was not deteriorated with time.
【００３１】これに対して、電気泳動粒子（比較試料
１）を用いた電気泳動表示素子では、粒子表面が樹脂で
覆われているために、電気泳動粒子の沈降は見られない
が、粒子が着色することでコントラストが低下し、応答
性が悪く、メモリー性に向上が見られなかった。On the other hand, in the electrophoretic display element using the electrophoretic particles (Comparative Sample 1), since the surface of the particles is covered with the resin, no sedimentation of the electrophoretic particles is observed, but the particles are not formed. By coloring, the contrast was lowered, the responsiveness was poor, and the memory property was not improved.
【００３２】また、未処理の電気泳動粒子を用いた電気
泳動表示素子では、泳動泳子の凝集沈降が起き、また電
極へ付着した粒子が取れないという結果であった。Further, in the electrophoretic display device using the untreated electrophoretic particles, the results were that the electrophoretic spores aggregated and settled, and the particles attached to the electrodes could not be removed.
【００３３】[0033]
【発明の効果】以上詳述したように、本発明によれば電
気泳動粒子は表面にポリマーのグラフト鎖が形成された
ものであることにより、電気泳動粒子の表面に位置する
水酸基がブロックされて電気泳動粒子の親油性が向上
し、分散媒中での電気泳動粒子の凝集あるいは電極への
付着が防止されるとともに、電気泳動粒子の見掛の比重
が低下して分散媒中での電気泳動粒子の沈降が防止され
る。そして、このような電気泳動粒子を用いた分散系を
電極板間に封入した電気泳動表示素子は、表示性に優れ
信頼性の高いものである。As described in detail above, according to the present invention, the electrophoretic particles have a polymer graft chain formed on the surface thereof, so that hydroxyl groups located on the surface of the electrophoretic particles are blocked. The lipophilicity of the electrophoretic particles is improved to prevent the electrophoretic particles from aggregating or adhering to the electrode in the dispersion medium, and the apparent specific gravity of the electrophoretic particles is reduced to cause electrophoresis in the dispersion medium. Settling of particles is prevented. An electrophoretic display element in which a dispersion system using such electrophoretic particles is enclosed between electrode plates has excellent displayability and high reliability.
【図１】本発明の電気泳動表示素子の構成を示す概略断
面図である。FIG. 1 is a schematic cross-sectional view showing the configuration of an electrophoretic display device of the present invention.
【図２】電気泳動粒子の分散安定性Ｓの測定結果を示す
図である。FIG. 2 is a diagram showing a measurement result of dispersion stability S of electrophoretic particles.
１…電気泳動表示素子 ２…透明基板 ３…透明電極 ４…基板 ５…分割電極 ６…スペーサ ７…密封空間 １１…分散系 １２…着色分散媒 １３…電気泳動粒子 DESCRIPTION OF SYMBOLS 1 ... Electrophoretic display element 2 ... Transparent substrate 3 ... Transparent electrode 4 ... Substrate 5 ... Divided electrode 6 ... Spacer 7 ... Sealed space 11 ... Dispersion system 12 ... Colored dispersion medium 13 ... Electrophoretic particles
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34281091AJPH05173193A (en) | 1991-12-25 | 1991-12-25 | Dispersed system for electrophoretic display and electrophoretic display element using the dispersed system |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34281091AJPH05173193A (en) | 1991-12-25 | 1991-12-25 | Dispersed system for electrophoretic display and electrophoretic display element using the dispersed system |
| Publication Number | Publication Date |
|---|---|
| JPH05173193Atrue JPH05173193A (en) | 1993-07-13 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34281091APendingJPH05173193A (en) | 1991-12-25 | 1991-12-25 | Dispersed system for electrophoretic display and electrophoretic display element using the dispersed system |
| Country | Link |
|---|---|
| JP (1) | JPH05173193A (en) |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002006345A (en)* | 2000-04-19 | 2002-01-09 | Fuji Xerox Co Ltd | Image display medium and image display device |
| JP2002328630A (en)* | 2001-02-20 | 2002-11-15 | Sharp Corp | Display device |
| WO2003091799A1 (en) | 2002-04-26 | 2003-11-06 | Bridgestone Corporation | Particle for image display and its apparatus |
| JP2004240409A (en)* | 2003-01-14 | 2004-08-26 | Natoko Kk | Electrophoretic color particle and display element |
| US6853477B2 (en) | 2001-04-27 | 2005-02-08 | Canon Kabushiki Kaisha | Particles for electrophoresis, a production method thereof and a display using the particles |
| US6950084B2 (en)* | 2000-09-29 | 2005-09-27 | Fuji Xerox Co., Ltd. | Image display medium and image forming apparatus |
| JP2005345568A (en)* | 2004-05-31 | 2005-12-15 | Canon Inc | Electrophoretic particles, production method thereof, and electrophoretic display element using electrophoretic dispersion |
| US7002728B2 (en) | 1997-08-28 | 2006-02-21 | E Ink Corporation | Electrophoretic particles, and processes for the production thereof |
| KR100575452B1 (en)* | 1999-09-28 | 2006-05-03 | 엘지.필립스 엘시디 주식회사 | Reflective type liquid crystal display using electrophoretic display and electrophoretic display |
| JP2006201617A (en)* | 2005-01-21 | 2006-08-03 | Seiko Epson Corp | Electrophoretic display dispersion and method for producing the same, microcapsule for electrophoretic display, electrophoretic display sheet, and electrophoretic display device |
| JP2006343782A (en)* | 1997-03-18 | 2006-12-21 | Massachusetts Inst Of Technol <Mit> | Microencapsulated electrophoretic or dielectrophoretic material |
| US7230750B2 (en) | 2001-05-15 | 2007-06-12 | E Ink Corporation | Electrophoretic media and processes for the production thereof |
| US7236290B1 (en) | 2000-07-25 | 2007-06-26 | E Ink Corporation | Electrophoretic medium with improved stability |
| US7247379B2 (en) | 1997-08-28 | 2007-07-24 | E Ink Corporation | Electrophoretic particles, and processes for the production thereof |
| JP2008171011A (en)* | 2001-02-20 | 2008-07-24 | Sharp Corp | Display device |
| US7405865B2 (en) | 2003-09-03 | 2008-07-29 | Mitsubishi Pencil Co., Ltd. | Liquid for electrophoretic display, display medium and display device using the same |
| US7411720B2 (en) | 2001-05-15 | 2008-08-12 | E Ink Corporation | Electrophoretic particles and processes for the production thereof |
| JP2008185990A (en)* | 2007-01-31 | 2008-08-14 | Ricoh Co Ltd | Electrophoretic particles and production method thereof, electrophoretic particle dispersion and image display device using the same |
| JP2008542809A (en)* | 2005-05-27 | 2008-11-27 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Robust multiparticulate system for color electrophoretic displays with very low drive voltage with small amounts of electrolyte |
| US7639428B2 (en) | 2004-08-25 | 2009-12-29 | Fujifilm Corporation | Optical element and image taking apparatus |
| JP2010244069A (en)* | 2010-06-21 | 2010-10-28 | Seiko Epson Corp | Method for producing microcapsules for electrophoretic display device |
| US7952791B2 (en) | 2007-05-18 | 2011-05-31 | Ricoh Company, Ltd. | Electrophoretic particle, electrophoretic particle dispersion liquid, image display medium, and image display device |
| US9323126B2 (en) | 2013-06-04 | 2016-04-26 | Seiko Epson Corporation | Electrophoretic particles, method for manufacturing electrophoretic particles, electrophoresis dispersion, display device, and electronic apparatus |
| KR20160115797A (en) | 2015-03-27 | 2016-10-06 | 세이코 엡슨 가부시키가이샤 | An electrophoretic dispersion, an electrophoresis sheet, an electrophoresis apparatus, and an electronic apparatus |
| US9645467B2 (en) | 2013-06-24 | 2017-05-09 | Seiko Epson Corporation | Electrophoretic particles, electrophoretic dispersion liquid, display sheet, display device, and electronic equipment |
| US9645466B2 (en) | 2013-06-24 | 2017-05-09 | Seiko Epson Corporation | Electrophoretic particles, electrophoretic dispersion liquid, display sheet, display device, and electronic equipment |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006343782A (en)* | 1997-03-18 | 2006-12-21 | Massachusetts Inst Of Technol <Mit> | Microencapsulated electrophoretic or dielectrophoretic material |
| US7002728B2 (en) | 1997-08-28 | 2006-02-21 | E Ink Corporation | Electrophoretic particles, and processes for the production thereof |
| US7247379B2 (en) | 1997-08-28 | 2007-07-24 | E Ink Corporation | Electrophoretic particles, and processes for the production thereof |
| KR100575452B1 (en)* | 1999-09-28 | 2006-05-03 | 엘지.필립스 엘시디 주식회사 | Reflective type liquid crystal display using electrophoretic display and electrophoretic display |
| JP2002006345A (en)* | 2000-04-19 | 2002-01-09 | Fuji Xerox Co Ltd | Image display medium and image display device |
| US7236290B1 (en) | 2000-07-25 | 2007-06-26 | E Ink Corporation | Electrophoretic medium with improved stability |
| US6950084B2 (en)* | 2000-09-29 | 2005-09-27 | Fuji Xerox Co., Ltd. | Image display medium and image forming apparatus |
| JP2002328630A (en)* | 2001-02-20 | 2002-11-15 | Sharp Corp | Display device |
| US7176991B2 (en) | 2001-02-20 | 2007-02-13 | Sharp Kabushiki Kaisha | Display |
| US7385654B2 (en) | 2001-02-20 | 2008-06-10 | Sharp Kabushiki Kaisha | Display |
| US7102704B2 (en) | 2001-02-20 | 2006-09-05 | Sharp Kabushiki Kaisha | Display |
| JP2008171011A (en)* | 2001-02-20 | 2008-07-24 | Sharp Corp | Display device |
| US6853477B2 (en) | 2001-04-27 | 2005-02-08 | Canon Kabushiki Kaisha | Particles for electrophoresis, a production method thereof and a display using the particles |
| US7230750B2 (en) | 2001-05-15 | 2007-06-12 | E Ink Corporation | Electrophoretic media and processes for the production thereof |
| US7411720B2 (en) | 2001-05-15 | 2008-08-12 | E Ink Corporation | Electrophoretic particles and processes for the production thereof |
| US7375875B2 (en) | 2001-05-15 | 2008-05-20 | E Ink Corporation | Electrophoretic media and processes for the production thereof |
| US7532388B2 (en) | 2001-05-15 | 2009-05-12 | E Ink Corporation | Electrophoretic media and processes for the production thereof |
| EP1500971A4 (en)* | 2002-04-26 | 2006-12-27 | Bridgestone Corp | Particle for image display and its apparatus |
| US7646530B2 (en) | 2002-04-26 | 2010-01-12 | Bridgestone Corporation | Particle and device for image display |
| WO2003091799A1 (en) | 2002-04-26 | 2003-11-06 | Bridgestone Corporation | Particle for image display and its apparatus |
| JP2004240409A (en)* | 2003-01-14 | 2004-08-26 | Natoko Kk | Electrophoretic color particle and display element |
| US7405865B2 (en) | 2003-09-03 | 2008-07-29 | Mitsubishi Pencil Co., Ltd. | Liquid for electrophoretic display, display medium and display device using the same |
| JP2005345568A (en)* | 2004-05-31 | 2005-12-15 | Canon Inc | Electrophoretic particles, production method thereof, and electrophoretic display element using electrophoretic dispersion |
| US7639428B2 (en) | 2004-08-25 | 2009-12-29 | Fujifilm Corporation | Optical element and image taking apparatus |
| JP2006201617A (en)* | 2005-01-21 | 2006-08-03 | Seiko Epson Corp | Electrophoretic display dispersion and method for producing the same, microcapsule for electrophoretic display, electrophoretic display sheet, and electrophoretic display device |
| JP2008542809A (en)* | 2005-05-27 | 2008-11-27 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Robust multiparticulate system for color electrophoretic displays with very low drive voltage with small amounts of electrolyte |
| JP2008185990A (en)* | 2007-01-31 | 2008-08-14 | Ricoh Co Ltd | Electrophoretic particles and production method thereof, electrophoretic particle dispersion and image display device using the same |
| US7952791B2 (en) | 2007-05-18 | 2011-05-31 | Ricoh Company, Ltd. | Electrophoretic particle, electrophoretic particle dispersion liquid, image display medium, and image display device |
| JP2010244069A (en)* | 2010-06-21 | 2010-10-28 | Seiko Epson Corp | Method for producing microcapsules for electrophoretic display device |
| US9323126B2 (en) | 2013-06-04 | 2016-04-26 | Seiko Epson Corporation | Electrophoretic particles, method for manufacturing electrophoretic particles, electrophoresis dispersion, display device, and electronic apparatus |
| US9645467B2 (en) | 2013-06-24 | 2017-05-09 | Seiko Epson Corporation | Electrophoretic particles, electrophoretic dispersion liquid, display sheet, display device, and electronic equipment |
| US9645466B2 (en) | 2013-06-24 | 2017-05-09 | Seiko Epson Corporation | Electrophoretic particles, electrophoretic dispersion liquid, display sheet, display device, and electronic equipment |
| KR20160115797A (en) | 2015-03-27 | 2016-10-06 | 세이코 엡슨 가부시키가이샤 | An electrophoretic dispersion, an electrophoresis sheet, an electrophoresis apparatus, and an electronic apparatus |
| EP3081984A2 (en) | 2015-03-27 | 2016-10-19 | Seiko Epson Corporation | Electrophoresis dispersion liquid, electrophoresis sheet, electrophoresis device, and electronic apparatus |
| US9804472B2 (en) | 2015-03-27 | 2017-10-31 | Seiko Epson Corporation | Electrophoresis dispersion liquid, electrophoresis sheet, electrophoresis device, and electronic apparatus |
| Publication | Publication Date | Title |
|---|---|---|
| JPH05173193A (en) | Dispersed system for electrophoretic display and electrophoretic display element using the dispersed system | |
| KR101711682B1 (en) | Silane-containing pigment particles for electrophoretic display | |
| US11493820B2 (en) | Color organic pigments and electrophoretic display media containing the same | |
| US8961831B2 (en) | Silane-containing pigment particles for electrophoretic display | |
| CN101699341B (en) | Electrophoretic dispersion solution, image display medium using the same, and image display device using the same | |
| US7532388B2 (en) | Electrophoretic media and processes for the production thereof | |
| CN103026283B (en) | Pigment particles for electrophoretic displays | |
| JP4780118B2 (en) | Method for producing display particles | |
| US20130244149A1 (en) | Charged pigment particles for electrophoretic display | |
| CN103183968A (en) | High molecular weight steric barrier for electrophoretic particles | |
| CA2282603A1 (en) | Polymeric-coated dielectric particles and formulation and method for preparing same | |
| WO1998037136A9 (en) | Polymeric-coated dielectric particles and formulation and method for preparing same | |
| JPH04166918A (en) | Display liquid for electrophoretic display device and electrophoretic display device using the display liquid | |
| KR101090039B1 (en) | Electrophoretic media | |
| KR101060980B1 (en) | Electrophoretic media | |
| US6765713B2 (en) | Electrophoretic composition, image display medium using same and image display device | |
| JPH03249739A (en) | Display liquid for electrophoresis display device and electrophoresis display device using the same | |
| JPH03249736A (en) | Display liquid for electrophoresis display device and electrophoresis display device using the same | |
| JP2013057875A (en) | Coating film formed on electrode surface of electrophoretic display device | |
| JPH03249737A (en) | Display liquid for electrophoresis display device and electrophoresis display device using the same | |
| JP3453381B2 (en) | Adhesive spacer for liquid crystal display panel, its manufacturing method and liquid crystal display panel | |
| JPH03249738A (en) | Display liquid for electrophoresis display device and electrophoresis display device using the same |