1300207 九、發明說明： 【發明所屬之技術領域】 技術領域 本發明係有關於一種顯示元件及其驅動方法、以及包 5含該顯示元件之資訊顯示系統。 L先前标】 背景技術1300207 IX. Description of the Invention: TECHNICAL FIELD The present invention relates to a display element and a method of driving the same, and an information display system including the display element. L previous standard] background technology
10 15 、近年來，在各企業、大學，對電子紙張進行之開發甚 為，、盛。包子紙張受到期待之應用市場，已有應用於以電 子書籍為首，甚至於行動終端機之副顯示裝置、及1C卡之 顯示部等，多種攜帶機器之方案。無線寫人之技術，被視 為電子紙張具發展性之應用技術之_，正在研究之中。須 存進行無線寫人之界面，有無線LAN、藍芽__她；蜜 錄_、及非接觸听方式等。利用無線lan或藍芽時， :須使電子紙張備有電池。另_方面，非接觸叫方式則 ^用頃取機/寫人機所發出之電波作為暫時的電源，進行κ 内=讀寫。由於電波強度為數十讀，因此藉由採用非接 卡方切實㈣電子紙張進行_之寫^不須具有 之無線、無電池驅動方式。 乍為電子紙張之纽顯示元件之_是❹膽固醇液晶 7元件。醇液晶之顯示元件由於具有可半永 地維持顯示之記憶性，因此可實現無線、無電池驅動 j所須之低耗電化。另外，利用膽固醇液晶之顯示元件 "可得到鮮明彩色顯示之彩色顯示特性、高對比、高解 20 1300207 析度等優異之特徵。膽固醇液晶是藉由在向列液晶中添加 較多量（數十％)之旋光性添加劑（亦稱為旋光性材料）而得 到，亦稱為旋光性向列（chiral nematic)液晶。膽固醇液晶形 成向列液晶分子定向成螺旋狀之膽固醇相。 5 利用膽固醇液晶之顯示元件係藉由控制液晶分子之定 向狀況來進行顯示。膽固醇液晶之定向狀態中，包括反射 入射光之水平螺旋狀態(P)、及使入射光穿透之垂直螺旋狀 態（FC)，且該等狀態在無電場之情形下皆可安定地存在。 垂直螺旋狀態之液晶層可讓光穿透，且水平螺旋狀態之液 10晶層則可會對應液晶分子之螺旋間距選擇性反射特定波長 之光。 第12(a)圖模式化顯示一般之液晶顯示元件之構成，且 第12⑻圖則模式化顯示利用_醇液晶之液晶顯示元件之 構成。如第12(a)圖所示，一般之液晶顯示元件具有紅(R)、 15綠(G)、監(B)之各色像素並排設置之液晶顯示層101。相對 地，如第12(b)圖所示，利用膽固醇液晶之液晶顯示元件則 -般具有分別S&置有R、G、B各色像素之3個液晶顯示層 101R、101G、1G1B積層而成之構造。液晶顯示層1〇iR、 1〇1G、1〇ib藉由使液晶分子之螺旋間距相異，可顯示R、G、 20 B各顏色。利用膽固醇液晶之液晶顯示元件與—般之液晶顯 不元件相比具有大約3倍之開口率。因此，利用膽固醇液晶 之液曰日頒不兀件由於具有一般之液晶顯示元件約3倍之光 利用效率（反射率），因此可實現鮮明之彩色顯示。 專利文獻1 :登錄實用新案第3089912號公報 1300207 專利文獻2 :特開2003-66413號公報 專利文獻3 :特開2002-108308號公報 【發明内容】 發明之揭示 5 本發明所欲解決之問題 然而，利用膽固醇液晶之進行彩色顯示之液晶顯示元 件具有3片之單色液晶顯示元件之積層構造，由於需要十數 V以上之驅動電壓，大幅增加改寫顯示時之消耗電力。另 外，利用微弱電波作為電力之無線、無電池驅動方式，若 10 通訊距離長則接收之電力會減少。因此，無線、無電池驅 動方式之液晶顯示元件有容易因電力不足產生動作不良之 問題。 本發明之目的係提供一種即使接收電力減少仍可穩定 運作之顯示元件及其驅動方法、以及包含該顯示元件之資 15 訊顯示系統。 解決問題之手段 前述目的可藉由一種顯示元件來達成。該顯示元件包 含有：顯示部，係積層有複數之顯示層者；無線送收訊部， 係接收含有前述複數顯示層之顯示資料之電波者；驅動電 20 壓產生部，係由接收到之前述電波產生用以驅動前述顯示 層之驅動電壓者；及控制部，係藉由前述驅動電壓同時驅 動依前述電波之收訊狀況決定之層數之前述顯示層者。 另外，前述目的亦可藉由如下之顯示元件來達成。一 種顯示元件，包含有：顯示部，係積層有複數之顯示層者； 1300207 無線送收訊部，係接收含有前述複數顯示層之顯示資料之 電波者；驅動電壓產生部，係由接收到之前述電波產生用 以驅動前述顯示層之驅動電壓者；及控制部，係依前述電 波之收訊狀況決定之掃描速度，藉由前述驅動電壓同時驅 5 動前述顯示層者。 又，前述目的亦可藉由如下之顯示元件驅動方法來達 成。一種顯示元件驅動方法，係依來自外部之接收電波驅 動具備積層有複數顯示層之顯示部之顯示元件者，而前述 顯示元件之驅動方法包含以前述接收電波產生用以驅動前 10 述顯示層之驅動電壓，並藉由前述驅動電壓同時驅動依前 述電波之收訊狀況決定之層數之前述顯示層。 再者，前述目的亦可藉由如下之資訊傳送裝置來達 成。一種資訊傳送裝置，包含有：無線送收訊部，係對具 備積層有複數顯示層之顯示部之顯示元件傳送電波，並接 15 收來自前述顯示元件之前述電波之收訊狀況資料者；及控 制部，係依前述收訊狀況資料產生對前述顯示元件傳送之 傳送資料者。 更，前述目的亦可藉由如下之資訊顯示系統來達成。 一種資訊顯示系統，包含有顯示元件及資訊傳送裝置，且 20 前述顯示元件包含有；顯示部，係積層有複數之顯示層者； 無線送收訊部，係接收含有前述複數顯示層之顯示資料之 電波者；驅動電壓產生部，係由接收到之前述電波產生用 以驅動前述顯示層之驅動電壓者；及控制部，係藉由前述 驅動電壓同時驅動依前述電波之收訊狀況決定之層數之前 1300207 述顯示層者，又，前述資訊傳送裝置包含有；無線送收訊 部，係對前述顯示元件傳送電波，並接收來自前述顯示元 件之前述收訊狀況資料者；及控制部，係依前述收訊狀況 資料產生對前述顯示元件傳送之傳送資料者。 5 發明之效果 依據本發明，可實現一種即使接收電力減少仍可穩定 動作之顯示元件及其驅動方法、以及包含該顯示元件之資 訊顯示系統。 圖式簡單說明 10 第1圖係模式化顯示依據本發明之一實施形態之資訊 顯示系統之圖。 第2圖係顯示依據本發明之一實施形態之資訊顯示系 統之方塊圖。 第3圖係顯示依據本發明之一實施形態之顯示元件構 15 .成之方塊圖。 第4圖係顯示膽固醇液晶之電壓反應特性之圖表。 第5圖係模式化顯示依據本發明之一實施形態之顯示 元件之顯示部構成之截面圖。 第6(a)〜(d)圖係顯示對掃描電極及訊號電極施加之電 20 壓波形之圖。 弟7(a)〜(c)圖係顯不對液晶層施加之電壓波形之圖。 第8(a)〜(e)圖係顯示依據本發明之一實施形態之顯示 元件驅動方法原理之圖。 第9圖係顯示依據本發明之一實施形態之顯示元件驅 9 1300207 動方法之圖。 第（）（b)圖係顯示依據本發明之一實施形態之顯示 元件驅動方法之變化例之圖。 $⑻（b)圖係顯示依據本發明之-實施形態之顯示 5元件驅動方法之另-變化例之圖。 第（a) (b)圖係模式化顯示液晶顯示元件構成之圖。 【實施方式】 實施發明之最佳形態 以下利用第1圖至第11圖說明依據本發明-實施形態 10之顯不兀★件及其驅動方法，以及利用該顯示元件之資訊顯 示系、先第1圖係換式化顯示依據本實施形態之資訊顯示系 統之方塊圖。如第i圖所示，資訊顯示系統】包含有無線傳 达預疋之顯7F貝sfL之顯示資轉送裝置2,及可接收無線傳 送,顯示資訊並可依該顯示資訊進行顯示之顯示元件3。顯 15示資訊#送裝置2與顯示元件3之間可相互通訊，例如是對 應ISO/IEC18092等之無線通訊規格，即近接型（通訊距離 10cm左右）之非接mc卡之通訊方式之相互通訊。另外，亦 可進行對應其他無線賴規格之通訊，例如密接型（通訊距 離2麵左右）、近距型（通訊距離lm左右）、及遠距型（通訊距 20離數m左右）之非接觸1C卡或非接觸1C卡以外之通訊方式。 顯示資訊傳送裝置2對顯示元件3輸出時脈訊號CLK、顯示 資料及驅動控制訊號等。顯示元件3不具有電池，以來自顯 示資訊傳送裝置2之電波作為動力源使用。顯示元件3之驅 動電路接收時脈訊號後啟動，該驅動電路係構成為接㈣ 1300207 示資料及驅動控制訊號後將該等轉送至顯示層。 第2圖係顯示依據本實施形態之顯示資訊傳送裝置2構 成之方塊圖。如第2圖所示，顯示資訊傳送裝置2具有控制 裝置内各電路之控制部20及供應各電路電力之電源部24。 5控制部20連接無線送收訊部21。無線送收訊部21透過天線 22進行與外部之無線通訊。另外控制部2〇亦連接記憶部 23。記憶部23具有储存預定程式及資料之唯讀記憶體與暫 時儲存資料之隨機存取記憶體。控制部20進行與主電腦間 各種資訊之傳送與接收。 10 第3圖係顯示依據本實施形態之顯示元件3構成之方塊 圖。如第3圖所示，顯示元件3包含有透過天線35與顯示資 Λ傳送裝置2之無線送收訊部21進行無線通訊之無線送收 訊部34;控制顯示元件3内各電路之控制部3〇;及積層有顯 不紅色（R)之顯不層（紅層）39R、顯示綠色（G)之顯示層C綠 15層）39G、顯示藍色(B)之顯示層（藍層）39B之顯示部38。各顯 示層39R、39G、39B具有例如通用之STN驅動器，以單純 之矩陣驅動方式驅動。另外顯示元件3不具有不變性記憶 控制部30具有判斷來自外部電波收訊狀況之機能。控 20制部30之電壓轉換電路31將接收之電波轉換為電屢 。直/交 流變流器32將電塵轉換電路Μ所產生電麼之位準轉會為數 位心虎並產生收訊電壓資料。驅動控制基本電路幻依收訊 電壓資料判斷電Μ之收訊狀況，蚊顯示層撤、39G、携 可同π驅動之層數。另外驅動控制基本電路％控制驅動多 11 1300207 工杰37所選擇之顯示層39(39R、39G或39B)之驅動器。電壓 轉換電路31並具有整流部及穩定部，且連接驅動電壓產生 電路36 °驅動電壓產生電路36係產生複數位準之驅動電 壓’以驅動顯示層39R、39G、39B。 5 在此’針對顯示部38進行說明。進行如本實施形態之 無線、無電池驅動時，顯示部38之顯示層宜為使用膽固醇 液晶之液晶顯示層。其第1項理由，是使用膽固醇液晶之液 曰曰頒不層具有記憶性。因此，一旦寫入各像素之顯示資料， 之後仍可維持而不須再定期地 寫入。因此，由於可以低速 10寫入故’肖耗電力小，可將微弱之收訊電力中大部分集中 供應至掃描中之像素。 其第2項理由，是由於膽固醇液晶具有高阻抗率，因此 /肖耗電流較少。反之，例如以電流驅動之有機£1^顯示或電 氣著色顯示等，則難以無電池驅動。 15 膽固醇液晶穩定之定向狀態有反射入射光之水平螺旋 狀態及使入射光穿透之垂直螺旋狀態。垂直螺旋狀態之液 晶層令光牙透，而水平螺旋狀態之液晶層則對應液晶分子 之螺旋間距選擇性反射特定波長之光。設水平螺旋狀態之 液晶層選擇性反射之光之中心波長為χ，液晶之平均折射率 20 為η，螺旋間距為Ρ，貝彳λ可以如下之數式表示。 λ=η · ρ 反射頻帶Δλ會隨著液晶之折射異向性Αη之增加而增 大。藉由在液晶層之外設置光吸收層，可在液晶為垂直螺 旋狀態時顯示黑色。 12 1300207 對膽固醇液晶施加電壓產生較強電場時，液晶分子之 螺旋構造會完全解開，液晶之定向狀態成為全部分子之長 軸方向與電場方向一致之垂直(homeotropic)狀態。接著， 若急速地去除垂直肤態液晶之電場，則液晶之螺旋軸會與 5電極垂直，成為水平螺旋狀態，選擇性反射對應液晶分^ 螺旋間距波長之光線。另一方面，使膽固醇液晶產生液晶 分子之螺旋構造不會完全解開之程度之較弱電場後，再去 除電場時，或者在產生較強電場後緩慢去除電場時，液晶 之螺旋軸會與電極平行，成為令入射光穿透之垂直螺旋狀 10態。另外，若供應中等強度之電場後再急遽地去除，則液 晶之定向狀態會成為水平螺旋狀態與垂直螺旋狀態混合存 在之狀態。該狀態時可進行中間色調之顯示。使用膽固醇 液晶之顯示元件，可利用該等現象進行資訊之顯示。 第4圖係顯示膽固醇液晶之電壓反應特性之圖表。圖表 15之橫軸顯示對液晶層施加脈衝電壓之大小（V)，縱軸顯示施 加脈衝電壓後液晶層之光反射率（相對值）。反射率相對較高 之狀態表不水平螺旋狀態（P)，相對較低之狀態則表示垂直 螺旋狀態（FC)。如第4圖所示，施加電壓之大小低於¥1(例 如4V)時，若液晶定向之初期狀態為水平螺旋狀態則會維持 2〇水平螺旋狀態，若初期狀態為垂直螺旋狀態則會維持垂直 螺旋狀態。 液晶定向之初期狀態為水平螺旋狀態時，施加V2以上 V3以下（V1<V2<V3)之較大脈衝電壓（例如24V左右），則定 向狀恶會轉換為垂直螺旋狀態，若施加V4以上（V3<V4)之 13 1300207 更大脈衝電壓(例如32V左右），則定向狀態會維持水平螺旋 狀態。另一方面，液晶定向之初期狀態為垂直螺旋狀態時， 施加V2以上V3以下之脈衝電壓，則定向狀態仍會維持垂直 螺旋狀態，若施加V4以上之脈衝電壓，則定向狀態會轉換 5為水平螺旋狀態。換言之，無論液晶之初期狀態為水平螺 旋狀悲返疋垂直螺旋狀癌’ V 2以上V 3以下之電壓範圍合成 為垂直螺旋狀悲之驅動頻帶’而V4以上之脈衝電壓會成為 水平螺旋狀態之驅動頻帶。 第5圖係模式化顯示使用膽固醇液晶之顯示部3 8之截 10面構成。如第5圖所示，顯示部38所具有之3張顯示層39B、 39G、39R，具有隔著封裝材44貼合之一對玻璃基板42、43。 玻璃基板42、43亦可以利用聚對苯二甲酸乙二酯、聚碳酸 酯等之膜基板取代。 玻璃基板42在與玻璃基板43對向之面上，形成有大略 15相互平行之複數帶狀之掃描電極48。另外玻璃基板43在與 玻璃基板42對向之面上，形成有大略相互平行之複數帶狀 之訊號電極50。從與基板面垂直之方向上看，掃描電極48 與讯號電極50係相互交叉地延伸。掃描電極48及訊號電極 50使用例如氧化銦錫(IT0; IndiumTin〇xide)來形成。亦可 2〇使用氧化銦鋅(IZO ; Indium Zic Oxide)等透明導電膜或石夕等 金屬電極，或者非晶性矽、氧化矽鉍(BS〇; BismuthSilic〇n Oxide)等光導電性膜來形成掃描電極48及訊號電極5〇。 掃描電極48及訊號電極50上宜覆蓋有絕緣性薄膜或定 向穩定化膜。絕緣性薄膜可防止電極間之短路並作為氣體 14 1300207 阻隔層阻隔氣體成分，具有提高液晶顯示層可靠性之機 能。定向穩定化膜可使用聚酸亞胺、聚醯胺醯亞胺、聚醚 醯亞胺、聚乙烯丁醛樹脂、及丙烯酸酯樹脂等有機膜，或 氧化矽、氧化鋁等無機材料。本例中掃描電極48、訊號電 5極50上覆蓋有定向穩定化膜。另外，定向穩定化膜亦可兼 用作為絕緣性薄膜。 玻璃基板42、43之間設有間隔體以維持均一之晶胞間 隙。間隔體可使用樹脂製或無機氧化物製之球狀間隔體、 表面覆蓋有熱可塑性樹脂之固接間隔體、及使用微影成像 10 法形成於基板上之柱狀間隔體等。 玻璃基板42、43之間形成有封裝室溫下顯示膽固醇相 之膽固醇液晶組成物之液晶層46。膽固醇液晶組成物係於 向列液晶組成物中添加1〇〜4〇wt%之旋光材料製成。在此 旋光材料之添加量係以向列液晶與旋光材料之合計量作為 100wt%日守之值。右旋光材料之添加量過多，則會由於向列 液晶之分子強烈地扭曲，使螺旋間距短，而選擇性反射短 波長之光。向列液晶可使用公知之各種材料，然而顧及驅 動黾壓，宜使用介電率異向性△8為2〇以上者。只要介電率 異向性Δε為20以上，驅動電壓就會相對較低。添加旋光材 〇料後之膽固醇液晶組成物之介電率異向性&宜為2〇〜5〇。 另外，折射率異向性么!；!宜為〇18〜〇 24。若折射率異向性八^ 小於該範圍，則水平螺旋狀態下的反射率會降低。反之， 若折射率異向性Δη大於該範圍，則垂直螺旋狀態下除亂反 射έ增大之外，黏度也會增高而降低反應速度。另外，液 15 1300207 βθ層之厚度（晶胞厚度）以3〜6μπ!左右為佳。晶胞厚度若小 於該範圍則水平螺旋狀態下之反射率會降低，若比該範圍 更厚則驅動電壓會過高。 本實施形態之顯示元件顯示部，從觀察者側（第5圖之 5上方）來看，為依序積層有在水平螺旋狀態下分別選擇性反 射藍、綠、紅光之3張顯示層39Β、39G、39R之構成。顯示 層39R在觀察者側之相反側（第5圖之下方），更可依須要設 置可見光吸收層40。顯示層39Β、39G、39R之晶胞間隙皆 為5μπι。構成顯示層39Β、39G、39R之液晶層46之向列液 1〇晶及旋光材料使用相同之材料，為透過旋光材料添加量之 不同以選擇性反射不同波長之光之構成。 顯示層39Β、39G、39R分別具有對掃描電極48及訊號 電極50施加脈衝電壓之驅動電路52。驅動電路52使用通用 之STN用驅動1C。例如在掃描側使用2個條輸出之stn 15驅動1C，在訊號側使用240條輸出之STN驅動IC。另外使用 齊納二極體以穩定化輸入驅動1C之電壓。雖然亦可以運算 放大器穩定電壓，但齊納二極體在省電之點上較適合無線 驅動。另外，以共通之驅動電壓產生電路36所產生之複數 位準之驅動笔壓’供應顯示層39B、39G、39R之各驅動電 20 路52。 第6圖係顯示該等驅動電路52對掃描電極佔及訊號電 極50施加脈衝電壓之1選擇期間（數〜數十咖）之電壓波 形。第6(a)關示為使液晶成為水平螺旋狀態而對訊號電極 50施加之電壓波形’第6(b)®顯示為使液晶成為垂直螺旋狀 16 !300207 “對訊號電極5輪加之電壓波形，刚顯示對選擇之 掃描電極48施加之電壓波形，第6(d)圖顯示對非選擇之掃描 ，極48施加之電壓波形。第7_顯示對驅動為水平螺旋二 紅像素之液晶層施加之電壓波形，第7(b)圖顯示對驅動為 5垂直螺旋狀態之像素之液晶層施加之電驗形。第7(〇圖顯 示對未選擇之像素之液晶層施加之電壓波形。 驅動為水平螺旋狀態之像素，在選擇時間之前半中， 如第6(a)圖所示，訊號電極5〇之電壓成為+32v，如第了⑻ 圖所示，該像素之液晶層會被施加有+32¥之電壓。而在選 10擇時間之後半中，訊號電極5〇之電壓成為〇v，掃描電極仙 之電壓成為+32V。因此，該像素之液晶層施加有柳之電 壓。如第7(c)圖所示，由於非選擇期間中施加之電壓為 或-4V，因此該像素之液晶層會被施加有大略±32乂之脈衝電 壓。藉此，該像素之液晶會成為水平螺旋狀態。由於膽固 15醇液晶具有記憶性，在施加脈衝電壓之後，仍會維持水平 螺旋狀態。 、 另方面，驅動為垂直螺旋狀態之像素，在選擇時間 之前半中，如第6(b)圖所示，訊號電極50之電壓成為+24V， 掃描電極之電壓會成為0V。因此，如第7(b)圖所示，該像 20素之液晶層會被施加有+24V之電壓。而在選擇時間之後半 中’訊號電極50之電壓成為8V，掃描電極48之電壓成為 +32V。因此，該像素之液晶層會被施加有-24V之電壓。由 於非選擇期間中施加之電壓為+4V或-4V，因此該像素之液 晶層會被施加有大略±24V之脈衝電壓。藉此，該像素之液 17 130020710 15 In recent years, in various companies and universities, the development of electronic paper has been very successful. The bun paper is expected to be used in the application market, and has been applied to a variety of portable devices, such as electronic books, sub-display devices for mobile terminals, and display units for 1C cards. The technology of wireless writing is regarded as the development technology of electronic paper, and is under study. There must be a wireless writing interface, such as wireless LAN, Bluetooth __ her; honey recording _, and non-contact listening. When using wireless lan or Bluetooth, the electronic paper must be equipped with a battery. On the other hand, the non-contact calling method is to use the radio wave generated by the pick-up/write man-machine as a temporary power source to perform κ internal=reading and writing. Since the intensity of the radio wave is dozens of readings, it is not necessary to have a wireless or battery-free driving method by using a non-contact card to reliably write (4) electronic paper.乍 is the electronic display element of the electronic paper. Since the display element of the alcohol liquid crystal has a memory property that can maintain the display semi-permanently, it is possible to achieve low power consumption required for wireless or batteryless driving. In addition, the display element using cholesteric liquid crystals can be characterized by excellent color display characteristics, high contrast, and high resolution 20 1300207 resolution. Cholesterol liquid crystals are obtained by adding a large amount (tens of percent) of an optically active additive (also referred to as an optically active material) to a nematic liquid crystal, and are also referred to as chiral nematic liquid crystals. The cholesteric liquid crystal forms a cholesterol phase in which the nematic liquid crystal molecules are oriented in a spiral shape. 5 Display elements using cholesteric liquid crystals are displayed by controlling the orientation of liquid crystal molecules. The directional state of the cholesteric liquid crystal includes a horizontal spiral state (P) for reflecting incident light and a vertical spiral state (FC) for penetrating incident light, and these states are stable in the absence of an electric field. The liquid crystal layer in the vertical spiral state allows light to pass through, and the liquid crystal layer in the horizontal spiral state selectively reflects light of a specific wavelength corresponding to the helical pitch of the liquid crystal molecules. Fig. 12(a) schematically shows the configuration of a general liquid crystal display element, and Fig. 12(8) shows a configuration of a liquid crystal display element using a liquid crystal. As shown in Fig. 12(a), a general liquid crystal display element has a liquid crystal display layer 101 in which pixels of respective colors of red (R), 15 green (G), and (B) are arranged side by side. On the other hand, as shown in Fig. 12(b), the liquid crystal display element using cholesteric liquid crystal generally has three liquid crystal display layers 101R, 101G, and 1G1B each having S, R, G, and B pixels. Construction. The liquid crystal display layers 1〇iR, 1〇1G, and 1〇ib can display the respective colors of R, G, and 20 B by making the spiral pitch of the liquid crystal molecules different. A liquid crystal display element using a cholesteric liquid crystal has an aperture ratio of about 3 times as compared with a general liquid crystal display element. Therefore, the use of the liquid crystal of the cholesteric liquid crystal can achieve a vivid color display because it has about three times the light use efficiency (reflectance) of a general liquid crystal display element. Patent Document 1: Japanese Unexamined Patent Publication No. Publication No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. Publication No The liquid crystal display element which performs color display by cholesteric liquid crystal has a laminated structure of three monochromatic liquid crystal display elements, and since a driving voltage of ten or more V is required, power consumption at the time of rewriting display is greatly increased. In addition, the weak electric wave is used as the wireless or battery-free driving method of electric power. If the communication distance is long, the received power will be reduced. Therefore, the liquid crystal display element of the wireless or batteryless type has a problem that it is easy to cause malfunction due to insufficient power. SUMMARY OF THE INVENTION An object of the present invention is to provide a display element which can stably operate even if reception power is reduced, a method of driving the same, and a video display system including the display element. Means for Solving the Problem The foregoing objects can be achieved by a display element. The display element includes: a display unit, which has a plurality of display layers; the wireless transmission and reception unit receives a radio wave containing the display material of the plurality of display layers; and the driving power 20 pressure generation unit receives the The radio wave generates a driving voltage for driving the display layer; and the control unit drives the display layer that determines the number of layers determined by the reception state of the radio wave by the driving voltage. In addition, the foregoing objects can also be achieved by the following display elements. A display element includes: a display portion, which has a plurality of display layers; 1300207 wireless receiving and receiving unit receives a radio wave containing display data of the plurality of display layers; and a driving voltage generating unit receives the received signal The radio wave generates a driving voltage for driving the display layer; and the control unit drives the display layer simultaneously by the driving voltage according to the scanning speed determined by the receiving state of the radio wave. Further, the above object can also be attained by the following display element driving method. A display element driving method for driving a display element having a display portion in which a plurality of display layers are stacked by external receiving waves, wherein the driving method of the display element includes generating the first 10 display layers by the received radio waves. Driving the voltage and simultaneously driving the display layer determined by the number of layers determined by the reception state of the radio wave by the driving voltage. Furthermore, the foregoing objects can also be attained by the following information transmitting apparatus. An information transmission device comprising: a wireless transmission and reception unit that transmits a radio wave to a display element having a display unit in which a plurality of display layers are stacked, and receives and receives information on the reception status of the radio wave from the display element; The control unit generates the transmission information transmitted to the display element based on the reception status data. Moreover, the foregoing objects can also be achieved by the following information display system. An information display system includes a display component and an information transmission device, and 20 of the display elements include: a display portion having a plurality of display layers; and a wireless transmission receiving portion receiving display data including the plurality of display layers a driving wave generating unit that generates a driving voltage for driving the display layer from the received radio wave; and a control unit that simultaneously drives the layer determined by the reception state of the radio wave by the driving voltage And the information transmission device includes: the wireless transmission and reception unit transmits the radio wave to the display element, and receives the reception status information from the display element; and the control unit The transmission information transmitted to the display element is generated according to the foregoing reception status data. Advantageous Effects of Invention According to the present invention, it is possible to realize a display element which can stably operate even if reception power is reduced, a method of driving the same, and an information display system including the display element. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view schematically showing an information display system according to an embodiment of the present invention. Figure 2 is a block diagram showing an information display system in accordance with an embodiment of the present invention. Fig. 3 is a block diagram showing a display element structure according to an embodiment of the present invention. Figure 4 is a graph showing the voltage response characteristics of cholesteric liquid crystals. Fig. 5 is a cross-sectional view showing the configuration of a display portion of a display element according to an embodiment of the present invention. Figures 6(a) to (d) show the voltage waveforms applied to the scan electrodes and the signal electrodes. The brothers 7(a) to (c) show a diagram of the voltage waveform applied to the liquid crystal layer. 8(a) to 8(e) are diagrams showing the principle of a display element driving method according to an embodiment of the present invention. Fig. 9 is a view showing a method of driving a display element drive 9 1300207 according to an embodiment of the present invention. The (b)th diagram shows a modification of the display element driving method according to an embodiment of the present invention. Fig. 8(b) and (b) are views showing another embodiment of the display of the 5-element driving method according to the embodiment of the present invention. The (a) and (b) drawings schematically show the configuration of the liquid crystal display element. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a display device according to the present invention and a driving method thereof, and an information display system using the display device will be described with reference to FIGS. 1 to 11 . 1 is a block diagram showing an information display system according to the present embodiment. As shown in the figure i, the information display system includes a display transfer device 2 that wirelessly transmits the preview, and a display element 3 that can receive wireless transmission, display information, and display according to the display information. . The communication information between the sending device 2 and the display device 3 can communicate with each other, for example, the wireless communication standard corresponding to ISO/IEC 18092, that is, the communication mode of the non-connected mc card communication mode of the proximity type (the communication distance is about 10 cm) . In addition, it is also possible to communicate with other wireless specifications, such as close-contact type (communication distance of about 2 sides), close-range type (communication distance lm or so), and remote type (communication distance of 20 minutes or so) non-contact Communication method other than 1C card or non-contact 1C card. The display information transmitting apparatus 2 outputs the clock signal CLK, the display data, the drive control signal, and the like to the display element 3. The display element 3 does not have a battery, and is used as a power source from radio waves from which the information transmitting device 2 is displayed. The driving circuit of the display component 3 is activated after receiving the clock signal, and the driving circuit is configured to transmit the data and the driving control signal to the display layer after receiving the data. Fig. 2 is a block diagram showing the configuration of the display information transmitting apparatus 2 according to the present embodiment. As shown in Fig. 2, the display information transmitting apparatus 2 has a control unit 20 that controls each circuit in the apparatus, and a power supply unit 24 that supplies power to each circuit. The control unit 20 is connected to the wireless transmission and reception unit 21. The wireless transmission and reception unit 21 performs wireless communication with the outside via the antenna 22. Further, the control unit 2 is also connected to the memory unit 23. The memory unit 23 has a read-only memory for storing a predetermined program and data, and a random access memory for temporarily storing data. The control unit 20 performs transmission and reception of various information with the host computer. Fig. 3 is a block diagram showing the configuration of the display element 3 according to the present embodiment. As shown in FIG. 3, the display element 3 includes a wireless transmission and reception unit 34 that wirelessly communicates with the wireless transmission and reception unit 21 of the display resource transmitting device 2 via the antenna 35; and a control unit that controls each circuit in the display element 3. 3〇; and the display layer has a red (R) display layer (red layer) 39R, display green (G) display layer C green 15 layer) 39G, display blue (B) display layer (blue layer) Display portion 38 of 39B. Each of the display layers 39R, 39G, and 39B has, for example, a general-purpose STN driver and is driven by a simple matrix driving method. Further, the display element 3 does not have an invariant memory. The control unit 30 has a function of judging the state of reception from an external radio wave. The voltage conversion circuit 31 of the control unit 30 converts the received electric wave into an electric power. The direct/AC converter 32 converts the level of electricity generated by the Dust converter circuit into a digital heart and generates the received voltage data. The drive control basic circuit illusion receives the voltage data to determine the reception status of the eMule, the mosquito display layer is removed, 39G, and the number of layers that can be driven by π. In addition, the drive control basic circuit % controls the drive of the display layer 39 (39R, 39G or 39B) selected by the driver 11 . The voltage conversion circuit 31 has a rectifying portion and a stabilizing portion, and is connected to a driving voltage generating circuit 36. The driving voltage generating circuit 36 generates a plurality of driving voltages ' to drive the display layers 39R, 39G, and 39B. 5 Here, the display unit 38 will be described. When the wireless or batteryless driving of the present embodiment is performed, the display layer of the display unit 38 is preferably a liquid crystal display layer using a cholesteric liquid crystal. The first reason is to use a liquid crystal of cholesteric liquid crystal to express memory. Therefore, once the display material of each pixel is written, it can be maintained thereafter without having to write periodically. Therefore, since the power can be written at a low speed of 10, most of the weak reception power can be supplied to the pixels in the scan. The second reason is that the cholesteric liquid crystal has a high impedance ratio, so the current consumption is small. Conversely, for example, a current-driven organic display or an electric color display, etc., it is difficult to drive without a battery. 15 The condensed state of the cholesteric liquid crystal has a horizontal spiral state that reflects incident light and a vertical spiral state that allows incident light to penetrate. The liquid crystal layer in the vertical spiral state causes light to pass through, and the liquid crystal layer in the horizontal spiral state selectively reflects light of a specific wavelength corresponding to the helical pitch of the liquid crystal molecules. It is assumed that the center wavelength of the light selectively reflected by the liquid crystal layer in the horizontal spiral state is χ, the average refractive index 20 of the liquid crystal is η, and the pitch of the spiral is Ρ, and the 彳λ can be expressed by the following formula. λ = η · ρ The reflection band Δλ increases as the refractive anisotropy η of the liquid crystal increases. By providing a light absorbing layer outside the liquid crystal layer, black can be displayed when the liquid crystal is in a vertical spiral state. 12 1300207 When a voltage is applied to the cholesteric liquid crystal to generate a strong electric field, the helical structure of the liquid crystal molecules is completely unraveled, and the orientation state of the liquid crystal becomes a homeotropic state in which the long axis direction of all molecules coincides with the direction of the electric field. Then, if the electric field of the vertical skin liquid crystal is rapidly removed, the spiral axis of the liquid crystal will be perpendicular to the five electrodes, and will be in a horizontal spiral state, and selectively reflect the light corresponding to the wavelength of the liquid crystal. On the other hand, when the cholesteric liquid crystal produces a weaker electric field to the extent that the helical structure of the liquid crystal molecules is not completely resolved, when the electric field is removed, or when the electric field is slowly removed after generating a strong electric field, the spiral axis of the liquid crystal and the electrode Parallel, it becomes a vertical spiral 10 state that allows incident light to penetrate. In addition, if a medium-strength electric field is supplied and then removed violently, the orientation state of the liquid crystal becomes a state in which the horizontal spiral state and the vertical spiral state are mixed. In this state, the display of the halftone can be performed. The use of cholesterol liquid crystal display elements can be used to display information. Figure 4 is a graph showing the voltage response characteristics of cholesteric liquid crystals. The horizontal axis of the graph 15 shows the magnitude (V) of the pulse voltage applied to the liquid crystal layer, and the vertical axis shows the light reflectance (relative value) of the liquid crystal layer after the application of the pulse voltage. The state with a relatively high reflectance does not have a horizontal spiral state (P), while the relatively low state represents a vertical spiral state (FC). As shown in Fig. 4, when the magnitude of the applied voltage is less than ¥1 (for example, 4V), if the initial state of the liquid crystal orientation is the horizontal spiral state, the horizontal spiral state is maintained, and if the initial state is the vertical spiral state, the state is maintained. Vertical spiral state. When the initial state of the liquid crystal orientation is the horizontal spiral state, when a large pulse voltage of V2 or more and V3 or less (V1 < V2 < V3) is applied (for example, about 24 V), the orientation-like evil is converted into a vertical spiral state, and if V4 or more is applied ( V13 <V4) 13 1300207 Larger pulse voltage (for example, about 32V), the orientation state will maintain the horizontal spiral state. On the other hand, when the initial state of the liquid crystal orientation is the vertical spiral state, when a pulse voltage of V2 or more and V3 or less is applied, the orientation state maintains the vertical spiral state. If a pulse voltage of V4 or more is applied, the orientation state is converted to 5 Spiral state. In other words, regardless of the initial state of the liquid crystal, the horizontal spiral sinus 疋 vertical spiral cancer 'V 2 or more V 3 or less is combined into a vertical spiral sorrow drive band' and the pulse voltage of V4 or higher becomes a horizontal spiral state. Drive band. Fig. 5 is a schematic view showing a configuration in which a display portion 38 of a cholesteric liquid crystal is used. As shown in FIG. 5, the three display layers 39B, 39G, and 39R included in the display unit 38 have a pair of glass substrates 42 and 43 bonded to each other via the package member 44. The glass substrates 42 and 43 may be replaced by a film substrate such as polyethylene terephthalate or polycarbonate. On the surface of the glass substrate 42 opposed to the glass substrate 43, a plurality of scanning electrodes 48 having a plurality of strips parallel to each other are formed. Further, on the surface of the glass substrate 43 opposed to the glass substrate 42, a plurality of signal electrodes 50 of a plurality of strips which are substantially parallel to each other are formed. The scan electrode 48 and the signal electrode 50 extend across each other as viewed in a direction perpendicular to the substrate surface. The scan electrode 48 and the signal electrode 50 are formed using, for example, indium tin oxide (ITO). Alternatively, a transparent conductive film such as indium zinc oxide (IZO; Indium Zic Oxide) or a metal electrode such as Shiki, or a photoconductive film such as amorphous yttrium or yttrium oxide (BS 〇; BismuthSilic〇n Oxide) may be used. The scan electrode 48 and the signal electrode 5 are formed. The scan electrode 48 and the signal electrode 50 should preferably be covered with an insulating film or a directional stabilizing film. The insulating film prevents short-circuit between the electrodes and acts as a barrier to gas in the gas barrier. It has the function of improving the reliability of the liquid crystal display layer. As the alignment-stabilizing film, an organic film such as polyamicimide, polyamidimide, polyetherimide, polyvinyl butyral resin, or acrylate resin, or an inorganic material such as cerium oxide or aluminum oxide can be used. In this example, the scan electrode 48 and the signal electrode 5 are covered with an alignment stabilizing film. Further, the orientation stabilizing film can also be used as an insulating film. Spacers are provided between the glass substrates 42, 43 to maintain a uniform cell gap. As the spacer, a spherical spacer made of a resin or an inorganic oxide, a fixed spacer covered with a thermoplastic resin, and a columnar spacer formed on the substrate by a lithography 10 method can be used. A liquid crystal layer 46 encapsulating a cholesterol liquid crystal composition exhibiting a cholesterol phase at room temperature is formed between the glass substrates 42 and 43. The cholesteric liquid crystal composition is prepared by adding 1 to 4% by weight of an optically active material to the nematic liquid crystal composition. The amount of the optically active material added is a total of the nematic liquid crystal and the optically active material as a value of 100% by weight. When the amount of the right-handed optical material is too large, the molecules of the nematic liquid crystal are strongly twisted, the spiral pitch is short, and the short-wavelength light is selectively reflected. As the nematic liquid crystal, various known materials can be used. However, in consideration of driving pressure, it is preferable to use a dielectric anisotropy Δ8 of 2 〇 or more. As long as the dielectric anisotropy Δ ε is 20 or more, the driving voltage is relatively low. The dielectric constant anisotropy of the cholesteric liquid crystal composition after the addition of the optically active material is preferably 2 〇 5 5 。. In addition, the refractive index anisotropy!;! should be 〇18~〇 24. If the refractive index anisotropy is less than this range, the reflectance in the horizontal spiral state is lowered. On the other hand, if the refractive index anisotropy Δη is larger than the range, the viscosity is increased and the reaction rate is lowered in addition to the increase in the disordered reflection enthalpy in the vertical spiral state. Further, the thickness (cell thickness) of the liquid 15 1300207 βθ layer is preferably about 3 to 6 μπ! If the cell thickness is smaller than this range, the reflectance in the horizontal spiral state is lowered, and if it is thicker than this range, the driving voltage is too high. The display element display unit of the present embodiment has three display layers 39 which selectively reflect blue, green, and red light in a horizontal spiral state as viewed from the observer side (above the fifth line of FIG. 5). The composition of 39G and 39R. The display layer 39R is on the opposite side of the viewer side (below the fifth drawing), and the visible light absorbing layer 40 may be provided as needed. The cell gaps of the display layers 39A, 39G, and 39R are all 5 μm. The nematic liquid 1 and the optically active material constituting the liquid crystal layer 46 of the display layers 39A, 39G, and 39R are made of the same material, and are configured to selectively reflect light of different wavelengths by the difference in the amount of the optically active material. The display layers 39A, 39G, and 39R respectively have drive circuits 52 for applying pulse voltages to the scan electrodes 48 and the signal electrodes 50. The drive circuit 52 uses a general-purpose STN drive 1C. For example, on the scanning side, two output STn 15 drives 1C, and on the signal side, 240 output STN drive ICs are used. In addition, a Zener diode is used to stabilize the input to drive the voltage of 1C. Although it is also possible to operate the amplifier to stabilize the voltage, the Zener diode is more suitable for wireless driving at the point of power saving. Further, each of the driving electrodes 20 of the display layers 39B, 39G, 39R is supplied with a driving pen pressure ' at a plurality of levels generated by the common driving voltage generating circuit 36. Fig. 6 is a view showing voltage waveforms of the selection period (several to several tens of coffee) in which the drive circuit 52 applies a pulse voltage to the scan electrode and the signal electrode 50. The sixth (a) is a voltage waveform applied to the signal electrode 50 to make the liquid crystal into a horizontal spiral state. The sixth (b)® is displayed so that the liquid crystal becomes a vertical spiral 16 ! 300207 "The voltage waveform applied to the signal electrode 5 The voltage waveform applied to the selected scan electrode 48 is just displayed, and the sixth (d) graph shows the voltage waveform applied to the non-selected scan, the pole 48. The 7th display shows the application of the liquid crystal layer driven to the horizontal spiral red pixel. The voltage waveform, Figure 7(b) shows the shape of the electromotive applied to the liquid crystal layer of the pixel that is driven to the 5 vertical spiral state. Figure 7 (〇图 shows the voltage waveform applied to the liquid crystal layer of the unselected pixel. In the horizontal spiral state, in the first half of the selection time, as shown in Fig. 6(a), the voltage of the signal electrode 5〇 becomes +32v. As shown in the figure (8), the liquid crystal layer of the pixel is applied. +32¥ voltage. In the second half of the selection time, the voltage of the signal electrode 5〇 becomes 〇v, and the voltage of the scanning electrode becomes +32V. Therefore, the liquid crystal layer of the pixel is applied with the voltage of the willow. As shown in Figure 7(c), due to the non-selection period In addition, the voltage is -4V, so the liquid crystal layer of the pixel is applied with a pulse voltage of about ±32 。. Thereby, the liquid crystal of the pixel will become a horizontal spiral state. Since the cholesterol 15 alcohol liquid crystal has memory, it is applied. After the pulse voltage, the horizontal spiral state is maintained. On the other hand, the pixel is driven to the vertical spiral state. In the first half of the selection time, as shown in Fig. 6(b), the voltage of the signal electrode 50 becomes +24V, scanning The voltage of the electrode will become 0 V. Therefore, as shown in Fig. 7(b), the liquid crystal layer of the image is applied with a voltage of +24 V. In the second half of the selection time, the voltage of the signal electrode 50 becomes 8 V. The voltage of the scan electrode 48 becomes +32 V. Therefore, the liquid crystal layer of the pixel is applied with a voltage of -24 V. Since the voltage applied during the non-selection period is +4 V or -4 V, the liquid crystal layer of the pixel is applied. There is a pulse voltage of ±24V. By this, the liquid of the pixel 17 1300207
10 1510 15
20 晶會成為垂直螺旋狀態。由於膽固醇液晶具有記憶性，在 施加脈衝電壓之後，仍會維持垂直螺旋狀態。 接著，說明本實施形態中顯示元件之驅動方法。在本 實施形態中，不具有電池而以收訊電波作為驅動電力源， 例如在驅動顯示元件，而該顯示元件之顯示部積層有使用 膽固醇液晶之顯示層時，同時驅動之顯示層之層數會依收 訊電波之強度而異。藉此，即使收訊電波之強度低，顯示 元件也不會產生動作不良，可寫入良好之顯示。 第8圖顯示本實施形態中顯示元件驅動方法之原理。圖 之橫方向表時間，以開始寫入之時間為0。本實施形態中， 在收訊電波之強度高、收訊電力充足（例如收訊電力大於 10mW左右）時，如第8(a)圖所示，同時驅動紅層（39R)、綠 層（39G)及藍層（39B)3層。從開始寫入顯示資料至結束為止 所須之時間，是與掃描240條線之時間相當之時間tl。設驅 動紅層時之消耗電力約為2.8mW、驅動綠層時之消耗電力 約為3.0m\V、驅動藍層時之消耗電力約為3.3mW，則同時 驅動3層所必須之電力為9.ImW左右。若包含其他電路之部 分，則必須之電力為10mW左右。 在收訊電力略為不足，難以同時驅動3層時（例如收訊 電力為7mW左右），如第8(b)、（c)圖所示，令同時驅動之層 數為2層。在第8(b)圖所示之例中，首先同時驅動紅層與綠 層2層，寫入第1線(Rl、G1)之顯示資料。Rl、G1之顯示資 料寫入完畢後，只驅動藍層寫入第1線(B1)之顯示資料。如 此，交互地驅動紅層、綠層及藍層，寫入至例如第240線為 18 1300207 止之顯示資料。 在第8(c)圖所示之例中，首先同時驅動紅層與綠層2 層，寫入全部線之顯示資料。在紅層及綠層全部線之寫入 結束後，只驅動藍層寫入全部線之顯示資料。此時，先從 5 顏色能見度高之層開始寫入顯示資料，則使用者可較早得 知顯示的整體内容。由於顏色之能見度依序是綠色、紅色、 藍色，因此宜如本例般先驅動紅層及綠層2層。20 crystals will become vertical spiral. Since the cholesteric liquid crystal has memory, the vertical spiral state is maintained after the application of the pulse voltage. Next, a method of driving the display element in the present embodiment will be described. In the present embodiment, the number of layers of the display layer that is simultaneously driven when the display unit of the display element is laminated with the display layer using the cholesteric liquid crystal is used, without the battery, and the received radio wave is used as the driving power source. It will vary depending on the strength of the receiving radio wave. Thereby, even if the strength of the received radio wave is low, the display element does not cause malfunction, and a good display can be written. Fig. 8 shows the principle of the display element driving method in the present embodiment. In the horizontal direction of the graph, the time to start writing is 0. In the present embodiment, when the strength of the received radio wave is high and the received power is sufficient (for example, the received power is greater than about 10 mW), as shown in Fig. 8(a), the red layer (39R) and the green layer (39G) are simultaneously driven. ) and the blue layer (39B) 3 layers. The time required from the start of writing the display data to the end is the time t1 corresponding to the time of scanning 240 lines. The power consumption when driving the red layer is about 2.8 mW, the power consumption when driving the green layer is about 3.0 m\V, and the power consumption when driving the blue layer is about 3.3 mW, and the power necessary to drive the three layers is 9 .ImW or so. If part of other circuits are included, the power must be around 10mW. When the receiving power is slightly insufficient, it is difficult to drive the three layers at the same time (for example, the receiving power is about 7 mW). As shown in the figure 8(b) and (c), the number of layers simultaneously driven is two. In the example shown in Fig. 8(b), first, the red layer and the green layer are simultaneously driven, and the display data of the first line (R1, G1) is written. After the display data of R1 and G1 is written, only the blue layer is written to the display data of the first line (B1). Thus, the red layer, the green layer, and the blue layer are alternately driven, and written to, for example, the display data of the 18th line is 18 1300207. In the example shown in Fig. 8(c), the red layer and the green layer 2 layer are simultaneously driven at the same time, and the display data of all lines is written. After the writing of all the lines of the red layer and the green layer is completed, only the blue layer is driven to write the display data of all the lines. At this time, the display data is written from the layer with high color visibility, and the user can know the overall content of the display earlier. Since the visibility of the color is green, red, and blue in order, it is preferable to drive the red layer and the green layer 2 layers as in this example.
此時，對於所驅動之層以外之層，宜切斷其電力之供 應，可有效地節省電力。同時驅動紅層及綠層2層所必須之 10 電力為5.8mW左右，而只驅動藍層所必須之電力為3.3mW 左右。如此，使同時驅動之層數為2層，可大幅減低消耗之 電力，即使收訊電力為7mW左右，仍可對3層寫入顯示資 料。而寫入顯示資料從開始到結束所須之時間，為掃描480 條線所需之t2(与2xtl)。但是，在第8(c)圖所示之例中，在 15 紅層與綠層全線之寫入結束之時間tl，即可得知顯示之内 容。 在收訊電力之供應更為不足時（例如收訊電力為4mW 左右），如第8(d)、（e)圖所示，令同時驅動之層數為1層。在 第8(d)圖所示之例中，首先只驅動綠層，寫入第1線(G1)之 20 顯示資料。G1之顯示資料寫入完畢後，只驅動紅層寫入第1 線(B1)之顯示資料。R1之顯示資料寫入完畢後，只驅動藍 層寫入第1線(B1)之顯示資料。如此，依序地驅動綠層、紅 層及藍層，寫入至第240線為止之顯示資料。 在第8(e)圖所示之例中，首先只驅動綠層寫入全部線之 19 1300207 顯示資料。在綠層全部線之寫入結束後，只驅動紅層寫入 全部線之顯示資料。在紅層全部線之寫入結束後，只驅動 藍層寫入全部線之顯示資料。如本例，藉由先從顏色能見 度高之層開始驅動，則使用者可較早得知顯示的整體内容。 5 如此，使驅動之層數為1層層依序驅動，可大幅減低消 耗之電力，即使收訊電力為4mW左右，仍可對3層寫入顯示 資料。而寫入顯示資料從開始到結束所須之時間，為掃描 720條線所必須之t3(与3xtl)。但是，在第8(e)圖所示之例 中，在綠層全線之寫入結束之時間tl，即可得知顯示之内 10 容。 第9圖係說明本實施形態中顯示元件驅動方法之圖。本 實施形態之前提，是顯示元件3靠近顯示資訊傳送裝置2之 顯示元件檢出步驟，及之後之相互認證步驟等兩步驟業已 完成。如第9圖所示，顯示資訊傳送裝置2向顯示元件3傳送 15 包含預定初始化資料之電波（步驟S1)，之後進入待命狀態 (步驟S2)。已接收初始化資料之顯示元件3初始化控制部30 及驅動電壓產生電路（電源部）36(步驟S3)。接著，顯示元件 3自接收之電波產生收訊狀態資料（步驟S4)，並將產生之收 訊狀態資料與顯示資料、驅動器控制資料要求(R E Q)訊號一 20 起往顯示資訊傳送裝置2傳送(步驟S5)。 業已接收收訊狀態資料與顯示資料、驅動器控制資料 要求(REQ)訊號之顯示資訊傳送裝置2之控制部20，依收訊 狀態資料決定同時驅動之層數。顯示資訊傳送裝置2則依決 定之層數編輯顯示資料及驅動器控制資料（步驟S6)，並在將 20 1300207 認識(ACK)訊號回傳顯衫件3之同時，將顯示資料及驅動 器控制資料往顯示元件3傳送(步驟S7)。換言之，顯示資訊 傳送裝置2在顯示元件3之收訊電波強度高時，如第8⑷圖所 不’將用以同時驅動紅層、綠層、藍層3層之控制資料，及 :於該等3層之顯示資料之混合後顯示資料傳送往顯示元 顯示資訊傳送裝置2在顯示元件3之收訊電波強度低 ^ ’則如第8⑻〜(e)圖所示，將用以驅動紅層、綠層、藍 属 S或1層之驅動益'控制資料，及對於驅動之2層或1 10 15 =“、’貞不貝料傳达在顯示元件3。驅動器控制資料包含有例 =取資料時脈、資料鎖存、掃描位移、脈衝極性、及電 傳^出按叙之各資料。顯示資料則是以每次一線份之方式 業已接收驅動器控制資料及顯示資料之顯示元件3,藉 正反電路儲存該兩資料(步驟S8)。顯示元们之控制部3〇 八'區動益控制貧料選擇驅動之顯示層，將接收之一條線部 =資料寫人選擇之顯示層。此時顯示元件3之控制部赚 刀畸對於未選擇顯示層之電力供應。 在顯Μ料之寫人結綠返回步㈣，_元件3之控 :=3〇再次產生收訊狀況資料並傳送1此，即使在顯示 二枓之寫人途中收訊狀況有變動，仍可同時驅動層數依變 後之收訊狀況決定之顯示層。絲是收訊狀況沒有變動 二未必須要產生、傳送收訊狀況資料。對於每-條線都重 ρ行步驟S5〜S8,寫人紅層、綠層、藍層3層之顯示資料。 舄入途中顯示元件3方面之電波收訊強度成為〇時，顯示 21 1300207 貧訊傳送裝42則依來自顯示元件3之REQ訊號之收訊次 數，再次傳送途中之顯示資料。藉此通訊再度開始時顯示 元件3可從寫入中斷之部分開始寫入顯示資料。 在如上之說明中，雖然同時驅動之顯示層層數由顯示 5兀件3方面之電波收訊狀況所決定，但顯然資訊傳送裝置2 之控制部20亦可依顯示元件3方面之電波收訊狀況決定顯 示層之掃描速度。藉由降低掃描速度，可減少將顯示資料 舄入顯不層時之消耗電力。換言之，使掃描速度隨著收訊 電波強度之降低而降低，並使掃描速度隨著收訊電波強度 10 之增加而增加即可。 接著’說明本實施形態之顯示元件及其驅動方法之變 化例。在顯示層使用膽固醇液晶時，縱然使用同一組成之 液aa，對個別之晶胞間隙進行調整，亦難以使各層之電壓 反應特性與第4圖中所示者完全一致。而且，若欲改變各層 15驅動脈衝之電壓值，則驅動電壓產生電路36會變得複雜。 第10圖顯示本變形例中對液晶層施加之驅動脈衝之波 形。第10(a)圖顯示藍層驅動脈衝之波形，第1〇(13)圖顯示藍 層及綠層驅動脈衝之波形。第1〇(a)、圖中上段顯示使液 晶成為水平螺旋狀態之驅動脈衝，下段顯示使液晶成為垂 2〇 直螺旋狀態之驅動脈衝。如第1 〇圖所示，本變形例中顯示 元件之控制部30以工作比各異之驅動脈衝驅動紅層、綠層 及藍層。藉由改變各層驅動脈衝之工作比，可補償電壓反 應特性之差異。例如，若藍層在特性上須要最高之驅動電 壓’則如第10圖所示，將藍層驅動脈衝之工作比設為 22 1300207 10 15 20 100%。相對地，若綠層及紅層所須之驅動電壓略低，則將 綠層及紅層驅動脈衝之工作比設為比100%低，而不改變其 電壓。另外，若紅層之驅動電壓又比綠層低時，只要將紅 層驅動脈衝之工作比設為比綠層低即可。依據本變形例， 由於各層可利用共通之驅動電壓產生電路36，因此可補償 各層電壓反應特性之差異，且不會增加成本或消耗電力。 接著’說明本實施形態之顯示元件之另一變化例。以 往具有電池之顯示元件，在改寫顯示時一般都會將前一次 顯示之全畫面進行全體重置。然而，在進行全畫面之全體 重置至少也會消耗數+ mW之電力。例如，在使用非接觸1(： 卡時，從讀取/寫入機方面供應之電力為5〜1〇碰。由於全 體重置賴之電力遠大於供應之電力，因此在不具有電池 之顯示元件方面進行全體重置是困難的。 第11⑻圖顯示利用本變化例改寫顯示元件之顯示畫面 之狀態’第11(_模式化顯示本變化例之驅動方法。如第 11(a)、（b)圖所示，本變化例中 線進行重置，同時隔著休條線(例如4條線⑽ 線)之顯示資料之寫人，且如上^、線）進仃寫人前頭線（1條 數相同。ϋ由進行如此之晝面^動作之重覆次數與線之總 抑制消耗電力。另外，不使用特|，比進行全體重置更能 之像素顯示白色者），而對宜> 1之重置資料(例如令全部 j馬八前頭繞 料本身會寫入重置線之像素，、 '、像素寫入之顯示資 y、’以進行曹番 在第11⑻圖中晝面之下半部分顯 晝面，上半部分顯示新 顯 不前一次顯示部分之 不之晝面。為仏批— 在此頒示從最上方之 23 1300207 5At this time, it is preferable to cut off the supply of electric power to the layer other than the layer to be driven, and it is possible to effectively save power. At the same time, the power required to drive the red and green layers is about 5.8 mW, and the power required to drive only the blue layer is about 3.3 mW. In this way, the number of layers to be simultaneously driven is two, which can greatly reduce the power consumption, and even if the received power is about 7 mW, the display information can be written to the third layer. The time required to write the display data from start to finish is the t2 (and 2xtl) required to scan 480 lines. However, in the example shown in Fig. 8(c), the content of the display can be known at time t1 when the writing of the red line and the green layer is completed. When the supply of the received power is even insufficient (for example, the received power is about 4 mW), as shown in the figure 8(d) and (e), the number of layers simultaneously driven is one. In the example shown in Fig. 8(d), first, only the green layer is driven, and the data of the first line (G1) is written. After the display data of G1 is written, only the red layer is written to the display data of the first line (B1). After the display data of R1 is written, only the blue layer is written to the display data of the first line (B1). In this way, the green layer, the red layer, and the blue layer are sequentially driven, and the display data up to the 240th line is written. In the example shown in Figure 8(e), first, only the green layer is written to the 19 1300207 display data of all lines. After the writing of all the lines of the green layer is completed, only the red layer is driven to write the display data of all the lines. After the writing of all the lines of the red layer is completed, only the blue layer is driven to write the display data of all the lines. As in this example, by first driving from a layer of high color visibility, the user can know the overall content of the display earlier. 5 In this way, the number of layers driven is sequentially driven by one layer, which can greatly reduce the power consumption. Even if the receiving power is about 4mW, the display data can be written to the third layer. The time required to write the display data from start to finish is the t3 (and 3xtl) necessary to scan 720 lines. However, in the example shown in Fig. 8(e), the time within the display at the time t1 when the writing of the entire green line is completed can be known. Fig. 9 is a view for explaining a method of driving a display element in the embodiment. Prior to this embodiment, the display element 3 is displayed near the display element detecting step of the display information transmitting apparatus 2, and the two steps of the mutual authentication step are completed. As shown in Fig. 9, the display information transmitting apparatus 2 transmits 15 radio waves including predetermined initialization data to the display element 3 (step S1), and then enters a standby state (step S2). The display element 3 that has received the initialization data initializes the control unit 30 and the drive voltage generating circuit (power supply unit) 36 (step S3). Then, the display component 3 generates the reception status data from the received radio wave (step S4), and transmits the generated reception status data and the display data and the driver control data request (REQ) signal 20 to the display information transmission device 2 ( Step S5). The control unit 20 of the display information transmitting apparatus 2 that has received the reception status data and the display data and the drive control data request (REQ) signal determines the number of layers to be simultaneously driven according to the reception status data. The display information transmitting device 2 edits the display data and the driver control data according to the determined number of layers (step S6), and displays the data and the drive control data while the 20 1300207 recognizes the (ACK) signal back to the display device 3. The display element 3 is transferred (step S7). In other words, when the intensity of the received signal wave of the display element 3 is high, as shown in FIG. 8(4), the display information transmitting device 2 is used to simultaneously drive the control data of the red, green, and blue layers, and: After the mixing of the display data of the 3 layers, the display data is transmitted to the display unit. The intensity of the received wave of the information transmitting device 2 on the display element 3 is low. ' As shown in the figure 8(8) to (e), it will be used to drive the red layer. The green layer, the blue genus S or the first layer of the drive benefit 'control data, and for the drive of the 2 layers or 1 10 15 = ", ' 贞 贝 not communicated in the display element 3. The drive control data contains examples = take information Clock, data latch, scan shift, pulse polarity, and telex output. The display data is the display component 3 that has received the drive control data and display data every time. The reverse circuit stores the two data (step S8). The display unit of the display unit 3 〇 ' 区 控制 控制 控制 控制 控制 控制 选择 选择 选择 选择 选择 选择 选择 选择 选择 选择 选择 选择 之一 之一 之一 之一 之一 之一 之一 之一 之一 之一 之一 之一 之一 之一 之一The control part of the display component 3 earns a knife distortion for the unselected display The power supply of the layer. In the case of the reading material, the green return step (4), the control of the component 3: =3, the data of the receiving status is generated again and transmitted, even if the receiving status of the writer is displayed on the way. If there is any change, the display layer determined by the reception status of the layer will be driven at the same time. The silk is that the reception status has not changed, and it is not necessary to generate and transmit the reception status data. For each line, the steps are repeated. S5~S8, the display data of the red layer, the green layer and the blue layer of the human layer are written. When the radio wave receiving strength of the component 3 is displayed on the way, the display 21 1300207 is transmitted from the display component 3 The number of times of receiving the REQ signal, and the display data on the way is transmitted again. When the communication is restarted, the display component 3 can write the display data from the portion where the write is interrupted. In the above description, although the display layer is simultaneously driven The number is determined by the radio wave reception status of the display 3, but it is obvious that the control unit 20 of the information transmission device 2 can also determine the scanning speed of the display layer according to the radio wave reception condition of the display element 3. By reducing the scanning speed , It is possible to reduce the power consumption when the display data is inserted into the display layer. In other words, the scanning speed is lowered as the intensity of the received wave is lowered, and the scanning speed is increased as the intensity of the received wave 10 is increased. A description will be given of a variation of the display element and the method for driving the same according to the embodiment. When the liquid crystal liquid crystal is used in the display layer, even if the liquid cell aa of the same composition is used, the individual cell gaps are adjusted, and it is difficult to make the voltage reaction characteristics of the respective layers and The one shown in Fig. 4 is completely identical. Further, if the voltage value of the drive pulse of each layer 15 is to be changed, the drive voltage generating circuit 36 becomes complicated. Fig. 10 shows the drive pulse applied to the liquid crystal layer in the present modification. Waveform. Figure 10(a) shows the waveform of the blue-layer drive pulse, and Figure 1(13) shows the waveform of the blue-layer and green-layer drive pulses. In the first step (a), the upper part of the figure shows a drive pulse for causing the liquid crystal to be in a horizontal spiral state, and the lower stage shows a drive pulse for causing the liquid crystal to be in a vertical spiral state. As shown in Fig. 1, in the present modification, the control unit 30 of the display element drives the red layer, the green layer, and the blue layer with different driving pulses. By varying the operating ratio of the drive pulses of each layer, the difference in voltage response characteristics can be compensated. For example, if the blue layer requires the highest driving voltage characteristic, then as shown in Fig. 10, the blue layer driving pulse operation ratio is set to 22 1300207 10 15 20 100%. In contrast, if the driving voltage required for the green layer and the red layer is slightly lower, the operating ratio of the green layer and the red layer driving pulse is set to be lower than 100% without changing the voltage. Further, if the driving voltage of the red layer is lower than that of the green layer, the operating ratio of the red layer driving pulse may be set to be lower than that of the green layer. According to the present modification, since the common driving voltage generating circuit 36 can be utilized for each layer, the difference in voltage reaction characteristics of the respective layers can be compensated without increasing the cost or power consumption. Next, another modification of the display element of the embodiment will be described. In the past, the display unit with the battery generally resets the entire screen of the previous display when the display is rewritten. However, at least a total of + mW of power is consumed in the overall reset of the full screen. For example, when using a non-contact 1 (: card, the power supplied from the reader/writer is 5 to 1 bump. Since the power of the entire reset is much larger than the power supplied, there is no display of the battery. It is difficult to perform overall resetting on the device side. Fig. 11(8) shows the state in which the display screen of the display element is rewritten by the present modification. [11] The method of driving the present variation is shown in Fig. 11 (a), (b) In the figure, the line is reset in this variation, and the person who displays the data through the line of the break (for example, the line of 4 lines (10)), and the above line, and the line in front of the line (1 line) The number is the same. The power consumption is reduced by the number of repetitions of the operation and the total suppression of the line. In addition, the special color is not used, and the pixel is more white than the overall reset, and the appropriate > 1 reset data (for example, all the j-heads will be written to the pixels of the reset line, ', the pixel write display y, ' to carry out Cao Fan under the 11th (8) picture Half of the display, the upper part shows the new display part of the previous display Day batch surface is Fo - here shown from above awarded the most 2313002075
10 1510 15
20 開始之寫入前頭線，即前述逐條之寫入線，大概到達畫 面之中央附近之狀態，在線上之資料執行寫入之同時，重 置線(例如4條線)上則執行使用寫入資料之重置。 本變化例中，在將顯示資料寫入像素前，將該像素之 液晶重置成為垂直狀態或垂直螺旋狀態。藉此，可將消耗 包力之增加抑制於最低限度，實現高對比之良好顯示。 以下製作本實施形態之顯示元件及顯示資訊傳送裝 置。頒不元件使用近接型B形式(TYPE-B)之非接觸ic卡。 顯示資訊傳送裝置則使用非接觸1C卡狀讀取/寫入器。令 、頁示元件罪近该讀取/寫入器，使距離小於lcm，則由於驅 動用之電力充足，因此同時寫入紅綠藍各層之顯示。接著， 使顯示元件與讀取/寫人11間之㈣為3em，則由於顯示元 件無法接收足以同時寫人紅綠藍各狀電力，因此先寫入 ^曰之"、員示’之後，再同時寫入藍層及紅層2層之顯示。若 更將顯不7L件與讀取/寫入器間之距離提高為&㈤，則會依 綠層—紅層〜藍層之順序寫人顯示。 卜C形式等B形式以外之形式，亦證實可同樣地進 行無線、無電池之寫入。 另外，令掃描速度可變亦可實現。在電力充足時，以 鶴波形3喊ne之掃描速度寫人，並對應電力之減少，降 低知為速度。另外，為補償紅綠藍各層驅動電壓之差異， 將驅動脈叙工作比設為藍層丨嶋、綠獅％、紅層鄕， 證貫可進行良好之補償。 如以上之說明，依據本實施形態，可省電且穩定地驅 24 1300207 動使用膽固醇液晶之無線、無電池驅動方式之顯示元件。 另外，由於依據本實施形態可使用廉價之通用驅動器，因 此可減低製造成本。更，依據本實施形態，可高速地進行 部分晝面之改寫。 5 本發明並不限定於上述之實施形態，可進行各種之變 化。 例如，在前述之實施形態中雖然舉使用膽固醇液晶之 顯示元件為例，但本發明並不限定於此，亦可適用其他以 電壓驅動且具記憶性之顯示元件（例如電泳等），其中，如果 10 是液晶之一種，則在物理穩定性之方面上特別適當。 【圖式簡單說明3 第1圖係模式化顯示依據本發明之一實施形態之資訊 顯示系統之圖。 第2圖係顯示本發明一實施形態之顯示資訊傳送裝置 15 之方塊圖。 第3圖係顯示本發明一實施形態之顯示元件構成之方 塊圖。 第4圖係顯示膽固醇液晶之電壓反應特性之圖表。 第5圖係模式化顯示本發明一實施形態之顯示元件之 20 顯示部構成之截面圖。 第6(a)〜(d)圖係顯示對掃描電極及訊號電極施加之電 壓波形之圖。 第7(a)〜(c)圖係顯示對液晶層施加之電壓波形之圖。 第8 (a)〜(e)圖係顯示依據本發明之一實施形態之顯示 25 1300207 元件驅動方法原理之圖。 第9圖係顯示依據本發明之一實施形態之顯示元件驅 動方法之圖。 第10(a)、（b)圖係顯示依據本發明之一實施形態之顯示 5 元件驅動方法之變化例之圖。 第11(a)、（b)圖係顯示依據本發明之一實施形態之顯示 元件驅動方法之另一變化例之圖。 第12(a)、（b)圖係模式化顯示液晶顯示元件構成之圖。 【主要元件符號說明】 1...資訊顯示系統 38...顯示部 2…顯示資訊傳送裝置 39R···顯示層（紅色層） 3...顯示元件 39G··.顯示層(綠色層) 20、30...控制部 39B···顯示層(藍色層） 21、34...無線送收訊部 40...可見光吸收層 22、35···天線 42、43…玻璃基板 23…記憶部 44...封裝材 24...電源部 46...液晶層 31...電壓轉換電路 48...掃描電極 32...直/交流變流器 50...訊號電極 33...驅動器控制基本電路 52...驅動電路 36...驅動電壓產生電路 37...多工器 2620 At the beginning, the front line is written, that is, the above-mentioned write line is about to reach the state near the center of the screen. When the data on the line is written, the write line (for example, 4 lines) is executed. Reset the data. In this variation, the liquid crystal of the pixel is reset to a vertical state or a vertical spiral state before the display material is written to the pixel. Thereby, the increase in the consumption power can be suppressed to a minimum, and a good display with high contrast can be achieved. The display element and display information transmitting apparatus of this embodiment are produced as follows. The non-contact ic card of the proximity type B form (TYPE-B) is used for the component. The display information transfer device uses a non-contact 1C card reader/writer. If the page reader component is close to the reader/writer, the distance is less than 1 cm, and since the power for driving is sufficient, the display of each layer of red, green and blue is simultaneously written. Then, if the (4) between the display element and the read/write person 11 is 3em, since the display element cannot receive enough power to write the red, green, and blue colors at the same time, the first write is performed after the " The display of the blue layer and the red layer 2 layer is simultaneously written. If the distance between the 7L and the reader/writer is increased to & (5), the display will be displayed in the order of green layer - red layer ~ blue layer. Forms other than the B form, such as the C form, have also confirmed that wireless and batteryless writing can be performed in the same manner. In addition, variable scanning speed can also be achieved. When the power is sufficient, write the person at the scanning speed of the crane waveform 3, and reduce the power to reduce the speed. In addition, in order to compensate for the difference in the driving voltage of each layer of red, green and blue, the driving pulse ratio is set to blue layer 丨嶋, green lion %, red layer 鄕, and the syndrome can be well compensated. As described above, according to the present embodiment, it is possible to save power and stably drive the display element of the wireless or batteryless driving method using the cholesteric liquid crystal. Further, since an inexpensive general-purpose driver can be used according to this embodiment, the manufacturing cost can be reduced. Further, according to the present embodiment, the rewriting of the partial face can be performed at a high speed. 5 The present invention is not limited to the above embodiments, and various changes can be made. For example, in the above-described embodiment, a display element using a cholesteric liquid crystal is exemplified, but the present invention is not limited thereto, and other voltage-driven and memory-sensitive display elements (for example, electrophoresis or the like) may be applied. If 10 is one of liquid crystals, it is particularly suitable in terms of physical stability. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view schematically showing an information display system according to an embodiment of the present invention. Fig. 2 is a block diagram showing a display information transmitting apparatus 15 according to an embodiment of the present invention. Fig. 3 is a block diagram showing the configuration of a display element according to an embodiment of the present invention. Figure 4 is a graph showing the voltage response characteristics of cholesteric liquid crystals. Fig. 5 is a cross-sectional view showing the configuration of a display unit of a display element according to an embodiment of the present invention. Figures 6(a) to (d) show the voltage waveforms applied to the scan electrodes and the signal electrodes. Figures 7(a) to (c) show diagrams of voltage waveforms applied to the liquid crystal layer. 8(a) to (e) are diagrams showing the principle of the display 25 1300207 element driving method according to an embodiment of the present invention. Fig. 9 is a view showing a display element driving method according to an embodiment of the present invention. Fig. 10 (a) and (b) are views showing a modification of the display 5 element driving method according to an embodiment of the present invention. Fig. 11 (a) and (b) are views showing another modification of the display element driving method according to an embodiment of the present invention. The 12th (a) and (b) drawings schematically show the configuration of the liquid crystal display element. [Description of main component symbols] 1...Information display system 38...Display section 2...Display information transfer device 39R···Display layer (red layer) 3...Display element 39G··.Display layer (green layer) 20, 30... Control unit 39B···Display layer (blue layer) 21, 34...Wireless transmission receiving unit 40... Visible light absorbing layer 22, 35··· Antenna 42, 43... Glass Substrate 23...memory portion 44...package material 24...power source portion 46...liquid crystal layer 31...voltage conversion circuit 48...scanning electrode 32...straight/alternating current converter 50... Signal electrode 33...driver control basic circuit 52...drive circuit 36...drive voltage generation circuit 37...multiplexer 26