1224942 11255twfl.doc/006 修正曰期93.9.3 玖、發明說明： 發明所屬之技術領城 本發明是有關於一種有機電激發光元件及其製造方 法，且特別是有關於一種能增進對比度的有機電激發光元 件及其製造方法。 先前技術 資訊通訊產業已成爲現今的主流產業，特別是可攜式 的各種通訊顯示產品更是發展的重點。而由於平面顯示器 是人與資訊之間的溝通界面，因此其發展顯得特別重要。 目前應用在平面顯示器的技術包括有電漿顯示器（Plasma Display Panel，PDP)、液晶顯示器(Liquid Crystal Display， LCD)、無機電激發光顯示器（Inorganic Electroluminescent Display，EL)、發光二極體(Light Emitting Diode)顯示器、 真空螢光顯示器（Vacuum Fluorescence Display，VFD)、場 致發射顯示器(Field Emission Display，FED)以及電變色顯 示器(Electro-Chromic Display)等。 相較於其他平面顯示器，有機電激發光元件以其自發 光、無視角、省電、製程簡易、低成本、操作溫度廣泛、 高應答速度以及全彩化等的優點，使其具有極大的潛力， 因此可望成爲下一代平面顯示器之主流。 有機電激發光元件係一種利用有機官能性材料 (organic functional materials)的自發光的特性來達到顯示 效果的元件，可依照有機官能性材料的分子量不同分爲小 分子有機發光元件（small molecule OLED，SM-OLED)與 高分子有機發光元件（polymer light-emitting device， 5 1224942 11255twfi.doc/006 修正日期93·9·3 PLED)兩大類。其發光結構皆是由一對電極以及有機官 能性材料層所構成。當電流通過透明陽極及金屬陰極間， 使電子和電洞在有機官能性材料層內結合而產生激子時， 便可以使有機官能性材料層依照其材料之特性，而產生不 同顏色之放光機制。 對於任何顯示器而言，全亮與全暗的亮度比値是決定 其識別度好壞的重大因素’此亮度比値爲一般所稱之對比 度（Contrast Ratio，CR)，若對比度越大則表示其識別度越 佳，而對比度的定義如下式（1)所示： ^subtoff ^amb__________( 1 ) 其中，Lsubw爲畫素（pixel)被點亮時的亮度，Lsub()ff爲畫 素未被點亮時的亮度’而Ramb爲外界光線進入顯示器內被 反射出的亮度，假設畫素被點亮時的亮度爲1〇〇，而未被 點亮時亮度爲1，則根據式（1)可計算出外界光線進入顯示 器內被反射出的亮度與顯示器的對比度之間的關係（如第i 圖所示）。第1圖爲繪示習知一種有機電激發光顯示器中對 比度與反射的亮度之間的關係圖，由第1圖可明顯的看出， 當外界光線從有機電激發光顯示器反射的量越多時，其對 比度會越小，亦即顯示器的識別度會越差。 第2圖爲繪示習知一種有機電激發光元件之剖面示 意圖。請參照第2圖，此其包括透明基板1〇〇、陽極層1〇2、 有機官能層1〇4與陰極層106。其中，陽極層102係配置 於透明基板100上，有機官能層104係配置於陽極層102 上’陰極層106係配置於有機官能層104上。其中，有機 6 1224942 11255twfl.doc/006 修正日期93.9.3 官能層104的折射率h和陽極層102的折射率n2非常接 近，而有機官能層104的折射率ηι大於透明基板1〇〇的折 射率n3,且n3大於外界空氣的折射率(si)，其中A約爲1.7 左右，n2約介於1.8至2.0之間，而n3約爲1·5左右。 有機電激發光元件所放射出的光線係由有機官能層 104所產生，而所產生光線的行進方向雖爲任意方向’但 當中的陰極層1〇6可視爲反射層，故光線僅能朝透明基板 1〇〇方向傳出。當外界光線W從透明基板1〇〇的方向進入 有機電激發光元件時，主要會於以下三個界面產生反射’ 之後再朝透明基板100方向傳出。 第一個界面是在空氣與透明基板100之間的界面，此 界面的反射光線^^約佔4%。第二個界面是在透明基板100 與陽極層102之間的界面，此界面的反射光線w2約佔0.8%。 第三個界面是在有機官能層104與陰極層106之間的界面， 此界面的反射光線W3則超過90%。 由此可知，大部份的反射光線是由第三個界面（有機 官能層104與陰極層106之間的界面）反射而產生的。換言 之，有機官能層104與陰極層106之間的界面是反射光線的 主要來源。 因此，在習知技術中，LUXELL公司提出一種改善有 機電激發光顯示器對比度的方法，其主要是在有機電激發 光元件之有機官能層與金屬陰極之間加入一層吸收層，此 吸收層係由一層薄的金屬半穿透層及一層透明的金屬氧化 物所構成，藉此吸收層而將外界光線吸收，以使其反射率 降至1%以下，進而提升顯示器的對比度。 7 11255twfl.doc/006 修正臼期93,9.3 然而，上述之方法雖然可吸收外界光線，以降低其反 射率，但在此同時，有機官能層所發出的光亦會被此吸收 層吸收，而使元件之發光效率減少約原來的一半。且吸收 層的形成係爲濺鍍（sPuttering)方式，亦會對有機官能層 造成損害。 另外，通常有機電激發光元件之有機官能層以及陰極 層是採用蒸鍍的方式形成’但是透明陽極層卻必須使用濺 鍍的方式進行鍍膜，因此，不同機台進行鍍膜除了會使所 需耗費的製程時間較長之外，還會有不同製程機台所產生 之膜層之間會有應力匹配的問題，進而導致良率下降、製 程成本增加。此外，習知使用吸收層以降低外界光線反射 率之技術中，其吸收層也是以濺鍍方式鍍製，因此同樣會 有較耗費製程時間以及不冋製程機台鑛製的膜層會有應力 匹配之問題。 發明內容 有鑑於此，本發明的目的就是在提供一種有機電激發 光元件，以提升在強光下的對比度，進而增加顯示器的識 別效果，且不會使元件的發光效率降低。 本發明的另一目的是提供一種有機電激發光元件的製 造方法，以使得有機電激發光元件中的各膜層都可以採用 蒸鍍的方法鍍膜，以減少製程時間並且避免不同製程機台 所鍍製之膜層會有應力匹配之問題。 本發明提出一種有機電激發光元件，此元件包括一透 明基板、一半反射半穿透導電層、一有機官能層以及一第 二電極層。其中半反射半穿透導電層係配置於透明基板上 1224942 11255twfl.doc/006 修正日期93.9.3 且其係作爲第一電極層之用，而且此半反射半穿透導電層 (例如是半反射半穿透金屬層）之材質可選自金或鋁等。 另外，有機官能層係配置於半反射半穿透導電層上，且其 總光學厚度係爲外界光主要波長的四分之一倍，亦即 η^Ι^^(1/4)λ，其中n。^爲有機官能層的折射率，I^g爲 有機官能層的總厚度，λ爲外界光主要波長，其介於 500nm〜600nm之間。此外，第二電極層係配置於有機官能 層上。由於本發明之第一電極層係爲具有半反射半穿透性 質’因此當外界的光線射入透明基板之後，一部份的光會 由透明基板與第一電極層之間的界面反射，另一部份的光 會穿透第一電極層，而從有機官能層與第二電極層之間的 界面反射，而且上述兩處所反射的光會彼此產生破壞性干 涉0 本發明提出一種有機電激發光元件的製造方法，此方 法係首先於基板上形成半反射半穿透導電層，此半反射半 穿透導電層係作爲第一電極層之用，其中所形成之半反射 胃導電層（例如是半反射半穿透金屬層）之材質可選 自金或錦等。之後，於半反射半穿透導電層上形成有機官 能層’此有機官能層的總光學厚度係爲外界光主要波長的 四分之一倍，亦即，其中nQrg爲有機官能層 的折射率’ I^g爲有機官能層的總厚度，λ爲外界光主要 波長’其介於5〇〇nm〜6〇〇nm之間。然後，於有機官能層 上形成第二電極層。特別是，上述之半反射半穿透導電層 (陽極層）、有機官能層與第二電極層（陰極層）都是採用相 同之製程方法，其例如是都採用蒸鍍製程來進行。 9 1224942 11255twfl.doc/006 修正日期 93.9.3 因此，由上可知，本發明之有機電激發光元件之第一 電極層係爲半反射半穿透導電層，此半反射半穿透導電層 除了作爲陽極之外，還可以使得外界的光在進入顯示器 後，在不同界面所反射的光會彼此產生破壞性干涉。而且， 此導電層並不會令有機官能層所發出來的光產生破壞性干 涉。 此外，由本發明之有機電激發光元件的製造方法可 知，元件中的第一電極層（陽極層）、有機官能層以及第二 電極層（陰極層）都採取蒸鍍方法鍍膜，因此本發明之方法 具有製程較爲簡便，且不會有因不同製程機台所產生之膜 層之間會有應力匹配之問題。 爲讓本發明之上述和其他目的、特徵、和優點能更明 顯易懂，下文特舉一較佳實施例，並配合所附圖式，作詳 細說明如下： 實施方式 第3A圖至第3C圖係繪示依照本發明一較佳實施例 的一種有機電激發光元件的製造流程剖面示意圖。請參照 第3A圖，有機電激發光元件的製造方法係首先於基板200 上形成半反射半穿透導電層202，且此半反射半穿透導電 層202係作爲第一電極層（例如陽極層）之用，而形成半 反射半穿透導電層202的方法例如是進行蒸鍍製程。此外， 半反射半穿透導電層202例如是一半反射半穿透金屬層， 且其材質可選自金或鋁等材質，其中若使用金作爲半反射 半穿透導電層202的材質，則其所形成的厚度約爲30nm 時，可以達到半反射半穿透的效果，而若使用鋁作爲半反 10 1224942 修正日期93.9.3 11255twfl.doc/006 射半穿透導電層202的材質，則其所形成的厚度約爲6nm 時，可以達到半反射半穿透的效果。另外，在各種半反射 半穿透導電層202的材質中又以金材質對於透明基板200 的黏著性最佳。此外，此半反射半穿透導電層202的材質 本身需具有高功函數的性質，如此在顯示器作動時，可以 降低電流傳輸的阻障。 透明基板200可以是一柔性（flexible)基板或一剛性 (rigid )基板。同時，透明基板200亦可以是一塑膠 (plastic)基板或是一玻璃基板。其中，柔性基板與塑膠 基板可爲一聚碳酸酯（polycarbonate，PC)基板、一聚酯 (polyester，PET)基板、一環嫌共聚物（cyclic olefin copolymer，C0C)基板或一金屬鉻合物基材一環烯共聚物 (metallocene- based cyclic olefin copolymer，mCOC)基 板。 之後，請參照第3B圖，於半反射半穿透導電層202 上形成有機官能層204,其形成方法例如是進行蒸鍍製程， 且有機官能層204的總光學厚度係爲外界光主要波長的四 分之一倍，亦即，其中η"爲有機官能層的 折射率’ I^g爲有機官能層的總厚度，λ爲外界光主要波 長，其介於500nm〜600nm之間。另外，有機官能層204 中例如是包括有電洞注入層、電洞傳輸層、有機發光層、 電子傳輸層與電子注入層依序堆疊於半反射半穿透導電層 202 上。 然後，請參照第3C圖，於有機官能層204上形成第 二電極層（例如陰極層）206，其中形成第二電極層206 11 1224942 修正日期93.9.3 11255twfl.doc/006 的方法例如是進行蒸鍍製程。 第二電極層206的材質係可選自但不限定爲鋁(A1)、 鈣（Ca)、鎂(Mg)、銦(In)、錫（Sn)、錳(Μη)、銀(Ag)、金(Au) 及含鎂之合金（例如鎂銀(Mg:Ag)合金、鎂銦(Mg:In)合金、 鎂錫（Mg:Sn)合金、鎂銻（Mg:Sb)合金及鎂碲（Mg:Te)合金） 等。 上述之有機電激發光元件中的各個膜層（例如：半反 射半穿透導電層202、有機官能層204與第二電極層206) 都可採取相同之製程方法，而此製程方法例如是蒸鍍製 程。因此，本發明之製造方法較爲簡便，而且不會有因不 同製程機台所產生之膜層之間會有應力匹配之問題。 另外，以下說明依照本發明之一較佳實施例的一種有 機電激發光元件的結構(如第4圖所示）。請參照第4圖， 此元件包括一透明基板200、一半反射半穿透導電層202、 一有機官能層204以及一第二電極層206。 其中，半反射半穿透導電層202係配置於透明基板200 上且其係作爲第一電極層（例如陽極層）之用。其中，半 反射半穿透導電層202 (例如半反射半穿透金屬層）之反 射率須相近於其穿透率，材質可選自金或鋁等，其中若使 用金作爲半反射半穿透導電層202的材質’則其所形成的 厚度約爲30nm時，可以達到半反射半穿透的效果，而若 使用鋁作爲半反射半穿透導電層202的材質，則其所形成 的厚度約爲6mn時，可以達到半反射半穿透的效果。另外’ 在各種半反射半穿透導電層202的材質中又以金材質對於 透明基板200的黏著性最佳。此外，此半反射半穿透導電 12 1224942 11255twn.doc/006 修正日期 93.9.3 層202的材質本身需具有高功函數的性質，如此在顯示器 作動時，可以降低電流傳輸的阻障。 透明基板200可以是一柔性（flexible)基板或一剛性 (rigid )基板。同時，透明基板200亦可以是一塑膠 (plastic)基板或是一玻璃基板。其中，柔性基板與塑膠 基板可爲一聚碳酸酯（polycarbonate，PC)基板、一聚酯 (polyester，PET)基板、一環烯共聚物（cyclic olefin copolymer，C0C)基板或一金屬鉻合物基材一環嫌共聚物 (metallocene- based cyclic olefin copolymer，mCOC)基 板。 另外，有機官能層204係配置於半反射半穿透導電層 202上，其中有機官能層204的總光學厚度係爲外界光主 要波長的四分之一倍，亦即，其中nQrg爲有 機官能層的折射率，I^g爲有機官能層的總厚度，λ爲外 界光主要波長，其介於500nm〜600nm之間。此外，第二 電極層（例如陰極層）206係配置於有機官能層204上。 除此之外，有機官能層204中更可包括電洞注入層、電洞 傳輸層、有機發光層、電子傳輸層與電子注入層依序堆疊 於半反射半穿透導電層202。 請繼續參照第4圖，在上述有機電激發光元件中所配 置的半反射半穿透導電層202可以使外界的光線X在射入 透明基板200之後，一部份的光Xi會由透明基板200與 半反射半穿透導電層202的界面反射出，另一部分的光線 X2則穿過半反射半穿透導電層202與有機官能層204，之 後由有機官能層204與陰極層206之間的界面反射出光線 13 1224942 11255twfl.doc/006 修正日期93.9.3 X2,。. 特別是，當有機官能層204的總光學厚度係爲外界光 主要波長的四分之一倍，自有機官能層204與第二電極層 206之間的界面反射出光線X2’，與自透明基板200與半 反射半穿透導電層202之間的界面反射出光線Xi會彼此 產生破壞性干涉，因此，利用本發明可以避免外界光線影 響顯示器之對比度。 除此之外，爲了證明本發明確實可行，以下特舉出有 機電激發光顯示器中對比度與外界亮度的關係圖（如第5圖 所示）以及半反射半穿透導電層厚度與反射率(reflectance)/ 穿透率(transmittance)的關係圖（如第6圖與第7圖所示）加以 說明。請參照第5圖，第5圖爲繪示本發明之有機電激發光 顯示器中對比度與外界亮度之間的關係圖，其中橫軸係表 示外界亮度，縱軸係表示顯示器對比度，實線Y/系表示利 用本發明所得之關係曲線，而實線¥2係表示利用習知技術 所得之關係曲線。 由第5圖可知，當外界亮度大於100時，利用習知技術 所得之對比度小於5(如¥2關係曲線所示），而利用本發明之 對比度仍可維持在20左右（如Yi關係曲線所示），意即利用 本發明的確可以降低外界光線對於顯示器之對比度的影 響。另外，當外界亮度小於5時，利用習知所得之對比度 大約爲80左右，而利用本發明所得之對比度則非常接近 1〇〇，意即微量的外界光線不會對本發明之顯示器的對比 度造成很大的影響。 此外，請參照第6圖，第6圖爲在光波長550nm的情況 1224942 修正日期93.9.3 11255twfl.doc/006 下利用金作爲半反射半穿透導電層的材質，其厚度與反射 率/穿透率的關係圖，其中橫軸表示導電層厚度(A)，縱軸 表示反射率（％)/穿透率（％)，而圖中之圓形標號係表示穿 透率（％)，矩形標號係表反射率（％)。由第6圖可知，反射 率會隨著膜厚的增加而增加，而穿透率會隨著膜厚的增加 而減少’而且當以金作爲材質的半反射半穿透導電層厚度 爲30nm時，其反射率及穿透率最爲接近，意即具有半反射 半穿透的效果。 另外，請參照第7圖，第7圖爲在光波長550nm的情況 下利用鋁作爲半反射半穿透導電層的材質，其厚度與反射 率/穿透率的關係圖，其中橫軸表示導電層厚度(人），縱軸 表示反射率（％)/穿透率（％)，而圖中之圓形標號係表示穿 透率（％)，矩形標號係表反射率（％)。由第7圖可知，反射 率會隨著膜厚的增加而增加，而穿透率會隨著膜厚的增加 而減少，而且當以鋁作爲材質的半反射半穿透導電層厚度 爲6nm時，其反射率及穿透率最爲接近，意即具有半反射 半穿透的效果。所以，由上述之金與鋁材質半反射半穿透 導電層厚度與反射率/穿透率的關係圖可知，達到半反射 半穿~透效_之導電層的厚度，會因薄膜材質的不同而有所 不同。 因此由上可知，本發明之有機電激發光元件可以有效 降低有機官能層與第二電極層之間的界面之反射光線W3 或X2’（如第2圖或第4圖所示），所以，本發明具有避免 顯示器的發光效率降低、提升在強光下的對比度以及增加 顯示器的識別效果等優點。此外，本發明之製程方法由於 15 1224942 11255twfl.doc/006 修正日期93.9.3 有機電激發光元件中的各個膜層都採取相同的製程，因此 具有製程簡便以及節省成本等優點。 雖然本發明已以一較佳實施例揭露如上，然其並非用 以限定本發明，任何熟習此技藝者，在不脫離本發明之精 神和範圍內，當可作些許之更動與潤飾，因此本發明之保 護範圍當視後附之申請專利範圍所界定者爲準。 圖式簡單說明 第1圖是習知的一種有機電激發光顯示器中對比度與 反射的亮度之間的關係圖； 第2圖是習知一種有機電激發光元件之剖面示意圖； 第3A圖至第3C圖是依照本發明一較佳實施例的一 種有機電激發光元件之製造流程剖面示意圖； 第4圖是依照本發明之一較佳實施例的一種有機電激 發光元件之剖面示意圖； 第5圖是本發明的一種有機電激發光顯示器中對比度 與外界亮度之間的關係圖，其中橫軸係表示外界亮度，縱 軸係表示顯示器對比度，實線Y!係表示利用本發明所得 之關係曲線，而實線γ2係表示利用習知技術所得之關係 曲線； 第6圖爲在光波長550nm的情況下利用金作爲本發明 之半反射半穿透導電層的材質，其厚度與反射率/穿透率 的關係圖，其中橫軸表示導電層厚度（人），縱軸表示反射 率（％)/穿透率（％)，而圖中之圓形標號係表示穿透率（％)， 矩形標號係表反射率(％);以及 第7圖爲在光波長550nm的情況下利用鋁作爲本發明 16 1224942 11255twfl.doc/006 修正日期93·9·3 之半反射半穿透導電層的材質，其厚度與反射率/穿透率 的關係圖，其中橫軸表示導電層厚度（A)，縱軸表示反射 率（％)/穿透率（％)，而圖中之圓形標號係表示穿透率（％)， 矩形標號係表反射率（％)。 圖式標記說明 100、200 :透明基板 102 :陽極層 104、204 :有機官能層 106 :陰極層 202 :半反射半穿透導電層 206 :第二電極層 W、Wi、W2、W3、X、Xi、X2、X2,：光線1224942 11255twfl.doc / 006 Revised date 93.9.3 发明, description of the invention: The technology to which the invention belongs The present invention relates to an organic electroluminescent device and a method for manufacturing the same, and in particular to a method capable of improving contrast Electromechanical excitation light element and manufacturing method thereof. Previous technology The information and communication industry has become the mainstream industry today, and especially various portable communication display products are the focus of development. The development of flat-panel displays is particularly important because they are the interface between people and information. The technologies currently used in flat panel displays include Plasma Display Panel (PDP), Liquid Crystal Display (LCD), Inorganic Electroluminescent Display (EL), and Light Emitting Diode) display, Vacuum Fluorescence Display (VFD), Field Emission Display (FED), and Electro-Chromic Display. Compared with other flat displays, organic electroluminescent devices have great potential due to their advantages such as self-emission, no viewing angle, power saving, simple process, low cost, wide operating temperature, high response speed, and full color. Therefore, it is expected to become the mainstream of next-generation flat-panel displays. Organic electroluminescent devices are devices that use the self-luminous properties of organic functional materials to achieve display effects. They can be divided into small molecule OLEDs according to the molecular weight of the organic functional materials. SM-OLED) and polymer organic light-emitting devices (polymer light-emitting device, 5 1224942 11255twfi.doc / 006 revision date 93 · 3 · 3 PLED). Its light emitting structure is composed of a pair of electrodes and an organic functional material layer. When an electric current is passed between the transparent anode and the metal cathode, and electrons and holes are combined in the organic functional material layer to generate excitons, the organic functional material layer can be caused to emit light in different colors according to the characteristics of the material. mechanism. For any display, the ratio of full brightness to full darkness is a significant factor that determines its recognition. This brightness ratio is generally called the Contrast Ratio (CR). If the contrast is larger, it means The better the degree of recognition, and the definition of contrast is shown in the following formula (1): ^ subtoff ^ amb __________ (1) where Lsubw is the brightness when the pixel (pixel) is lit, and Lsub () ff is the pixel has not been spotted Brightness when lit 'and Ramb is the brightness reflected by outside light entering the display, assuming that the brightness of the pixel when it is lit is 100, and the brightness when it is not lit is 1, then according to formula (1), Calculate the relationship between the brightness of the external light entering the display and the contrast of the display (as shown in Figure i). Fig. 1 is a graph showing the relationship between the contrast and the reflected brightness in a conventional organic electroluminescent display. From Fig. 1, it can be clearly seen that when the external light reflects from the organic electroluminescent display, the more The smaller the contrast, the lower the recognition of the display. Fig. 2 is a schematic cross-sectional view showing a conventional organic electroluminescent device. Please refer to FIG. 2, which includes a transparent substrate 100, an anode layer 102, an organic functional layer 104, and a cathode layer 106. Among them, the anode layer 102 is disposed on the transparent substrate 100, and the organic functional layer 104 is disposed on the anode layer 102. The cathode layer 106 is disposed on the organic functional layer 104. Among them, organic 6 1224942 11255twfl.doc / 006 revised date 93.9.3 The refractive index h of the functional layer 104 and the refractive index n2 of the anode layer 102 are very close, and the refractive index η of the organic functional layer 104 is larger than the refractive index of the transparent substrate 100. Rate n3, and n3 is greater than the refractive index (si) of the outside air, where A is about 1.7, n2 is between 1.8 and 2.0, and n3 is about 1.5. The light emitted by the organic electro-optical excitation element is generated by the organic functional layer 104. Although the traveling direction of the generated light is arbitrary, the cathode layer 106 in the middle can be regarded as a reflective layer, so the light can only be transparent. The substrate goes out in the 100 direction. When external light W enters the organic electro-optical light emitting element from the direction of the transparent substrate 100, it will mainly reflect at the following three interfaces and then be transmitted toward the transparent substrate 100. The first interface is the interface between the air and the transparent substrate 100, and the reflected light ^^ at this interface accounts for about 4%. The second interface is the interface between the transparent substrate 100 and the anode layer 102, and the reflected light w2 at this interface accounts for about 0.8%. The third interface is the interface between the organic functional layer 104 and the cathode layer 106, and the reflected light W3 at this interface exceeds 90%. It can be seen that most of the reflected light is generated by the reflection of the third interface (the interface between the organic functional layer 104 and the cathode layer 106). In other words, the interface between the organic functional layer 104 and the cathode layer 106 is the main source of reflected light. Therefore, in the conventional technology, LUXELL company proposes a method for improving the contrast of organic electroluminescent display, which is mainly adding an absorption layer between the organic functional layer of the organic electroluminescent device and the metal cathode. The absorption layer is composed of It consists of a thin metal semi-transparent layer and a transparent metal oxide. The absorption layer absorbs external light to reduce the reflectance to less than 1%, thereby improving the contrast of the display. 7 11255twfl.doc / 006 Modified acetabular period 93, 9.3 However, although the above method can absorb external light to reduce its reflectivity, at the same time, the light emitted by the organic functional layer will also be absorbed by this absorbing layer, and Reduce the luminous efficiency of the device by about half. Moreover, the formation of the absorbing layer is sputtering, which also causes damage to the organic functional layer. In addition, the organic functional layer and the cathode layer of an organic electroluminescent device are usually formed by vapor deposition. However, the transparent anode layer must be coated by sputtering. Therefore, in addition to coating on different machines, it will cost more. In addition to the long process time, there will also be the problem of stress matching between the film layers produced by different process machines, which will lead to a decrease in yield and an increase in process costs. In addition, in the conventional technology that uses an absorbing layer to reduce the external light reflectivity, the absorbing layer is also plated by sputtering, so it will also take a long time to process and the film layer made of non-manufacturing equipment will have stress. The problem of matching. SUMMARY OF THE INVENTION In view of this, the object of the present invention is to provide an organic electroluminescent device to improve the contrast under strong light, thereby increasing the recognition effect of the display without reducing the luminous efficiency of the device. Another object of the present invention is to provide a method for manufacturing an organic electroluminescent device, so that each layer in the organic electroluminescent device can be coated by evaporation, so as to reduce the process time and avoid plating by different process equipment. The produced film will have the problem of stress matching. The present invention provides an organic electro-optic light-emitting device, which includes a transparent substrate, a semi-reflective and trans-conductive layer, an organic functional layer, and a second electrode layer. The semi-reflective and transflective conductive layer is arranged on a transparent substrate. 1224942 11255twfl.doc / 006 The date of revision is 93.9.3 and it is used as the first electrode layer. The semi-reflective and transflective conductive layer (for example, semi-reflective) The semi-penetrating metal layer) can be selected from gold or aluminum. In addition, the organic functional layer is disposed on the semi-reflective and transflective conductive layer, and its total optical thickness is a quarter of the main wavelength of external light, which is η ^ Ι ^^ (1/4) λ, where n. ^ Is the refractive index of the organic functional layer, I ^ g is the total thickness of the organic functional layer, and λ is the main wavelength of external light, which is between 500nm and 600nm. The second electrode layer is disposed on the organic functional layer. Because the first electrode layer of the present invention has a semi-reflective and transflective property, after external light enters the transparent substrate, a part of the light will be reflected by the interface between the transparent substrate and the first electrode layer. Part of the light will penetrate the first electrode layer and be reflected from the interface between the organic functional layer and the second electrode layer, and the light reflected at the two places will cause destructive interference with each other. The present invention proposes an organic electrical excitation A method for manufacturing an optical element. This method first forms a semi-reflective and semi-transparent conductive layer on a substrate. The semi-reflective and semi-transparent conductive layer is used as a first electrode layer. The semi-reflective gastric conductive layer (for example, It is semi-reflective and semi-transparent metal layer) and the material can be selected from gold or brocade. Then, an organic functional layer is formed on the semi-reflective and transflective conductive layer. 'The total optical thickness of the organic functional layer is a quarter of the main wavelength of external light, that is, where nQrg is the refractive index of the organic functional layer.' I ^ g is the total thickness of the organic functional layer, and λ is the main wavelength of external light, which is between 500 nm and 600 nm. Then, a second electrode layer is formed on the organic functional layer. In particular, the above-mentioned semi-reflective and semi-transmissive conductive layer (anode layer), organic functional layer, and second electrode layer (cathode layer) all adopt the same process method, for example, they are all performed by evaporation process. 9 1224942 11255twfl.doc / 006 Date of amendment 93.9.3 Therefore, it can be seen from the above that the first electrode layer of the organic electro-optic light-emitting element of the present invention is a semi-reflective and semi-transparent conductive layer. As an anode, after the external light enters the display, the light reflected at different interfaces can cause destructive interference with each other. Moreover, the conductive layer does not cause destructive interference with the light emitted from the organic functional layer. In addition, according to the manufacturing method of the organic electroluminescent device of the present invention, it can be known that the first electrode layer (anode layer), the organic functional layer, and the second electrode layer (cathode layer) in the element are all deposited by the vapor deposition method. The method has a simple process and does not have the problem of stress matching between the film layers generated by different process machines. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below and described in detail with the accompanying drawings as follows: FIG. 3A to FIG. 3C FIG. 4 is a schematic cross-sectional view illustrating a manufacturing process of an organic electroluminescent device according to a preferred embodiment of the present invention. Referring to FIG. 3A, a method of manufacturing an organic electro-optical light-emitting device is to first form a semi-reflective semi-transmissive conductive layer 202 on a substrate 200, and the semi-reflective semi-transmissive conductive layer 202 serves as a first electrode layer (for example, an anode layer). ), And the method of forming the semi-reflective and transflective conductive layer 202 is, for example, a vapor deposition process. In addition, the semi-reflective and semi-transmissive conductive layer 202 is, for example, a semi-reflective and semi-transmissive metal layer, and its material can be selected from materials such as gold or aluminum. If gold is used as the material of the semi-reflective and semi-transmissive conductive layer 202, When the thickness is about 30nm, the effect of semi-reflective and semi-transmissive can be achieved, and if aluminum is used as the semi-reflective 10 1224942 correction date 93.9.3 11255twfl.doc / 006 the material of the semi-transmissive conductive layer 202, its When the thickness is about 6nm, the effect of half reflection and half penetration can be achieved. In addition, among various materials of the semi-reflective and transflective conductive layer 202, a gold material has the best adhesion to the transparent substrate 200. In addition, the material of the semi-reflective and transflective conductive layer 202 itself needs to have a high work function, so that when the display is operated, the barrier to current transmission can be reduced. The transparent substrate 200 may be a flexible substrate or a rigid substrate. Meanwhile, the transparent substrate 200 may also be a plastic substrate or a glass substrate. The flexible substrate and the plastic substrate may be a polycarbonate (PC) substrate, a polyester (PET) substrate, a cyclic olefin copolymer (C0C) substrate, or a metal chromium substrate. A metallocene-based cyclic olefin copolymer (mCOC) substrate. Then, referring to FIG. 3B, an organic functional layer 204 is formed on the semi-reflective and transflective conductive layer 202. The method for forming the organic functional layer 204 is, for example, an evaporation process, and the total optical thickness of the organic functional layer 204 is the main wavelength of external light. One-fourth, that is, where η " is the refractive index of the organic functional layer 'I ^ g is the total thickness of the organic functional layer, and λ is the main wavelength of external light, which is between 500nm and 600nm. In addition, the organic functional layer 204 includes, for example, a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and an electron injection layer sequentially stacked on the semi-reflective and transflective conductive layer 202. Then, referring to FIG. 3C, a second electrode layer (eg, a cathode layer) 206 is formed on the organic functional layer 204. The second electrode layer 206 is formed. 11 1224942 The date of revision is 93.9.3 11255twfl.doc / 006. Evaporation process. The material of the second electrode layer 206 may be selected from, but not limited to, aluminum (A1), calcium (Ca), magnesium (Mg), indium (In), tin (Sn), manganese (Μη), silver (Ag), Gold (Au) and magnesium-containing alloys (such as magnesium silver (Mg: Ag) alloy, magnesium indium (Mg: In) alloy, magnesium tin (Mg: Sn) alloy, magnesium antimony (Mg: Sb) alloy, and magnesium tellurium ( Mg: Te) alloy) and so on. Each film layer in the above organic electro-optic light-emitting device (for example: semi-reflective and transflective conductive layer 202, organic functional layer 204, and second electrode layer 206) can adopt the same process method, and this process method is, for example, steaming Plating process. Therefore, the manufacturing method of the present invention is relatively simple, and there is no problem of stress matching between the film layers generated by different process machines. In addition, the structure of an organic electroluminescent device according to a preferred embodiment of the present invention is shown below (as shown in FIG. 4). Referring to FIG. 4, the device includes a transparent substrate 200, a semi-reflective and transflective conductive layer 202, an organic functional layer 204, and a second electrode layer 206. The semi-reflective and transflective conductive layer 202 is disposed on the transparent substrate 200 and serves as a first electrode layer (for example, an anode layer). The reflectivity of the semi-reflective and semi-transmissive conductive layer 202 (for example, the semi-reflective and semi-transmissive metal layer) must be close to its transmittance. The material can be selected from gold or aluminum. Among them, if gold is used as the semi-reflective semi-transmissive The material 'of the conductive layer 202' can achieve a semi-reflective and transflective effect when the thickness is about 30 nm, and if aluminum is used as the material of the semi-reflective and semi-transmissive conductive layer 202, the thickness formed is about When it is 6mn, the effect of half reflection and half penetration can be achieved. In addition, among various materials of the semi-reflective and transflective conductive layer 202, a gold material has the best adhesion to the transparent substrate 200. In addition, this semi-reflective and transflective conductivity 12 1224942 11255twn.doc / 006 Modified Date 93.9.3 The material of the layer 202 itself must have a high work function property, so that when the display is activated, the barrier to current transmission can be reduced. The transparent substrate 200 may be a flexible substrate or a rigid substrate. Meanwhile, the transparent substrate 200 may also be a plastic substrate or a glass substrate. The flexible substrate and the plastic substrate may be a polycarbonate (PC) substrate, a polyester (PET) substrate, a cyclic olefin copolymer (C0C) substrate, or a metal chromium substrate. A metallocene-based cyclic olefin copolymer (mCOC) substrate. In addition, the organic functional layer 204 is disposed on the semi-reflective and transflective conductive layer 202. The total optical thickness of the organic functional layer 204 is a quarter of the main wavelength of external light, that is, where nQrg is an organic functional layer. The refractive index, I ^ g is the total thickness of the organic functional layer, and λ is the main wavelength of external light, which is between 500nm and 600nm. The second electrode layer (for example, the cathode layer) 206 is disposed on the organic functional layer 204. In addition, the organic functional layer 204 may further include a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and an electron injection layer sequentially stacked on the semi-reflective and transflective conductive layer 202. Please continue to refer to FIG. 4. The semi-reflective and semi-transmissive conductive layer 202 disposed in the organic electro-optic light-emitting element can allow external light X to enter the transparent substrate 200, and a part of the light Xi will pass through the transparent substrate. The interface between 200 and the semi-reflective semi-transparent conductive layer 202 is reflected, and the other part of the light X2 passes through the semi-reflective semi-transparent conductive layer 202 and the organic functional layer 204, and then the interface between the organic functional layer 204 and the cathode layer 206 Reflected light 13 1224942 11255twfl.doc / 006 Revised date 93.9.3 X2 ,. In particular, when the total optical thickness of the organic functional layer 204 is a quarter of the main wavelength of external light, light X2 'is reflected from the interface between the organic functional layer 204 and the second electrode layer 206, and is transparent. The light rays Xi reflected from the interface between the substrate 200 and the semi-reflective and semi-transmissive conductive layer 202 will cause destructive interference with each other. Therefore, the present invention can prevent external light from affecting the contrast of the display. In addition, in order to prove that the present invention is indeed feasible, the following specifically lists the relationship between the contrast and the external brightness in the organic electroluminescent display (as shown in Figure 5), and the thickness and reflectance of the semi-reflective and transflective conductive layer ( The relationship between reflectance) / transmittance (as shown in Figure 6 and Figure 7) will be described. Please refer to FIG. 5. FIG. 5 is a graph showing the relationship between the contrast and the external brightness in the organic electroluminescent display of the present invention. The horizontal axis represents the external brightness, and the vertical axis represents the display contrast. The solid line Y / Indicates a relationship curve obtained by using the present invention, and a solid line ¥ 2 indicates a relationship curve obtained by using a conventional technique. It can be seen from Figure 5 that when the external brightness is greater than 100, the contrast obtained by the conventional technology is less than 5 (as shown by the ¥ 2 relationship curve), and the contrast of the present invention can still be maintained at about 20 (as shown by the Yi relationship curve). (Shown), which means that the use of the present invention can indeed reduce the effect of external light on the contrast of the display. In addition, when the external brightness is less than 5, the conventionally obtained contrast ratio is about 80, and the contrast ratio obtained by the present invention is very close to 100, which means that a small amount of external light will not cause much contrast to the display of the present invention. Great influence. In addition, please refer to Fig. 6, which shows the case of the light wavelength of 550nm. 1224942 Revised date 93.9.3 11255twfl.doc / 006 Uses gold as the material of the semi-reflective and semi-transmissive conductive layer. Its thickness and reflectivity / penetration Transmittance relationship diagram, where the horizontal axis represents the thickness of the conductive layer (A), the vertical axis represents the reflectance (%) / transmittance (%), and the round numbers in the figure represent the transmittance (%), rectangular The labels refer to reflectance (%). It can be seen from Fig. 6 that the reflectance increases with the increase of the film thickness, and the transmittance decreases with the increase of the film thickness. And when the thickness of the semi-reflective and semi-transmissive conductive layer with gold is 30 nm, , Its reflectance and transmittance are the closest, which means it has the effect of semi-reflective and semi-transparent. In addition, please refer to FIG. 7, which is a graph of the relationship between the thickness and the reflectance / transmittance using aluminum as the material of the semi-reflective and semi-transmissive conductive layer at a wavelength of 550 nm, where the horizontal axis represents conductivity The layer thickness (person), the vertical axis represents the reflectance (%) / transmittance (%), while the circular numbers in the figure indicate the transmittance (%), and the rectangular numbers indicate the reflectance (%). As can be seen from Fig. 7, the reflectance increases with the increase of the film thickness, and the transmittance decreases with the increase of the film thickness. When the thickness of the semi-reflective and semi-transmissive conductive layer with aluminum is 6 nm, , Its reflectance and transmittance are the closest, which means it has the effect of semi-reflective and semi-transparent. Therefore, from the above graph of the thickness of the semi-reflective and transflective conductive layer of gold and aluminum materials and the reflectance / transmittance, it can be known that the thickness of the conductive layer that achieves semi-transparent and transflective ~ transmissivity will depend on the film material. It's different. Therefore, it can be known from the above that the organic electro-optical excitation light element of the present invention can effectively reduce the reflected light W3 or X2 ′ (as shown in FIG. 2 or 4) at the interface between the organic functional layer and the second electrode layer. The invention has the advantages of avoiding the reduction of the luminous efficiency of the display, improving the contrast under strong light, and increasing the recognition effect of the display. In addition, the manufacturing method of the present invention has the advantages of simple manufacturing process, cost saving, and the like because each film layer in the organic electroluminescent device adopts the same manufacturing process because 15 1224942 11255twfl.doc / 006 is revised. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes and retouch without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application. Brief Description of the Drawings Figure 1 is a relationship diagram between contrast and reflected brightness in a conventional organic electroluminescent display; Figure 2 is a schematic sectional view of a conventional organic electroluminescent device; Figures 3A to 1 FIG. 3C is a schematic cross-sectional view of a manufacturing process of an organic electroluminescent device according to a preferred embodiment of the present invention; FIG. 4 is a schematic cross-sectional view of an organic electroluminescent device according to a preferred embodiment of the present invention; The figure is the relationship between contrast and external brightness in an organic electroluminescent display of the present invention, where the horizontal axis represents the external brightness, the vertical axis represents the display contrast, and the solid line Y! Represents the relationship curve obtained by using the present invention. The solid line γ2 represents the relationship curve obtained by using conventional techniques; Figure 6 shows the use of gold as the material of the semi-reflective and transflective conductive layer of the present invention at a light wavelength of 550 nm, and its thickness and reflectance / penetration Transmittance relationship diagram, where the horizontal axis represents the thickness of the conductive layer (person), the vertical axis represents the reflectance (%) / transmittance (%), and the round numbers in the figure indicate penetration Rate (%), the rectangular number refers to the reflectance (%); and Figure 7 shows the use of aluminum as the present invention at a wavelength of 550 nm. 16 1224942 11255twfl.doc / 006 half-reflective The relationship between the thickness of the transparent conductive layer and its reflectance / transmittance. The horizontal axis represents the thickness of the conductive layer (A), and the vertical axis represents the reflectance (%) / transmittance (%). The round number indicates the transmittance (%), and the rectangular number indicates the reflectance (%). Description of reference numerals 100, 200: transparent substrate 102: anode layer 104, 204: organic functional layer 106: cathode layer 202: semi-reflective and transflective conductive layer 206: second electrode layer W, Wi, W2, W3, X, Xi, X2, X2 ,: light
Yi、Y2 : PJ係曲線 17Yi, Y2: PJ curve 17