201013618 六、發明說明： 【發明所屬之技術領域】 本發明大體上關於一種於電流驅動顯示器内平衡一共模 電壓之方法及裝置。特定言之，本發明提供一種回饋方 法’該方法藉由感測電流驅動顯示器（諸如一被動式矩陣 驅動有機電致發光顯示器）内之共模電壓而自動校正誤 差。 【先前技術】 • 有機發光二極體（OLED)包括一具有特別有優勢形式之 電光顯示器。該等二極體明亮、五彩繽紛、切換快速、提 供一寬視角且容易及實惠製造於各種基板上。 有機（此處包含有機金屬）LED藉由使用各種顏色（其取決 於所使用之材料）之聚合物或小分子而被製造，。基於聚 合物之有機LED之實例被描述於WO 90/13148、WO 95/06400及WO 99/48160中；基於小分子之器件之實例被 描述於美國專利第4,539,507號；及基於樹枝狀聚合物材料 ® 之實例被描述於WO 99/21935及WO 02/067343中。 於圖la中繪示一典型有機LED之基本結構100。一破璃 ； 或塑膠基板1〇2支撐一透明陽極層104(其包括（例如））氡化 銦錫（ITO))，在該透明陽極層1〇4上沈積一電洞傳輪層 106、一電致發光層1〇8及一陰極110。例如，該電致發光 層108可包括PEDOT:PSS(聚苯乙烯-加硫聚乙烯-二氣喧 吩）》陰極層110典型包括低功函數金屬（諸如鈣）且可包含 緊鄰近電致發光層108之一額外層（諸如一鋁層），用於改良 I41682.doc 201013618 電子能階匹配。至陽極及陰極的接觸導線114及116分別提 供至一電源118的一連接。小分子器件亦可採用相同基本 結構。 於圖la繪示之實例中，光12〇被發射穿過透明陽極層1〇4 及基板102，此等器件被稱作「底部發射器」。亦可構造穿 過陰極發射之器件，例如，藉由保持陰極層11〇之厚度小 於50毫米至100毫米使得陰極大體上係透明的。 有機LED可沈積於一矩陣像素基板上以形成一單色或多 色像素化顯示器。可使用紅、綠及藍發射像素群來構造一 多色顯示器。在此等顯示器中，通常係藉由啟動列（或行） 線以選擇像素而定址個別元件，列（或行）像素被寫入至個 別兀件，以產生一顯示。所謂的主動式矩陣顯示器具有與 各像素相關聯之一記憶體元件，該記憶體元件通常係一儲 存電容器及一電晶體，而被動式矩陣顯示器沒有此記憶體 元件，而是作為替代地被重複掃描’其有點相似於一電視 圖像’以給予一穩定影像之印象。 圖lb顯示穿過一被動式矩陣顯示器15〇之一橫斷面，其 中相似於圖la中之該等元件由相同元件符號表示。在該被 動式矩陣顯示器150中，電致發光層1〇8包括複數個像素 152，且陰極層11〇包括複數個相互電絕緣傳導線^彳，傳 導線154係佈線進入圖lb頁面中，各傳導線均具有一相關 聯之接點156。同樣地，氧化銦錫陽極層1〇4亦包括複數個 陽極線其中圖lb中僅繪示一個陽極線，陽極線係以 與陰極線成直角地佈線。亦提供用於各陽極線的接點（未 141682.doc 201013618 繪不於圖lb)。在陰極線與陽極線之交叉點處之一電致發 光像素152可藉由在相關陽極線與陰極線之間施加一電壓 而被定址。201013618 VI. Description of the Invention: TECHNICAL FIELD OF THE INVENTION The present invention generally relates to a method and apparatus for balancing a common mode voltage in a current driven display. In particular, the present invention provides a feedback method that automatically corrects for errors by sensing the common mode voltage within a current driven display such as a passive matrix driven organic electroluminescent display. [Prior Art] • An organic light emitting diode (OLED) includes an electro-optic display having a particularly advantageous form. These diodes are bright, colorful, fast to switch, provide a wide viewing angle, and are easy and affordable to manufacture on a variety of substrates. Organic (herein containing organometallic) LEDs are manufactured by using polymers or small molecules of various colors depending on the materials used. Examples of polymer-based organic LEDs are described in WO 90/13148, WO 95/06400, and WO 99/48160; examples of small molecule-based devices are described in U.S. Patent No. 4,539,507; and based on dendrimer materials Examples of ® are described in WO 99/21935 and WO 02/067343. A basic structure 100 of a typical organic LED is illustrated in FIG. a glass substrate; or a plastic substrate 1 2 supports a transparent anode layer 104 (including, for example, indium tin oxide (ITO)), and a hole transport layer 106 is deposited on the transparent anode layer 1〇4, An electroluminescent layer 1 〇 8 and a cathode 110. For example, the electroluminescent layer 108 can comprise PEDOT:PSS (polystyrene-sulphurized polyethylene-diode porphin) cathode layer 110 typically comprising a low work function metal (such as calcium) and can comprise close proximity to electroluminescence An additional layer of layer 108, such as an aluminum layer, is used to improve the electronic energy level matching of I41682.doc 201013618. Contact wires 114 and 116 to the anode and cathode provide a connection to a power source 118, respectively. Small molecule devices can also use the same basic structure. In the example illustrated in FIG. 1a, light 12〇 is emitted through transparent anode layer 1〇4 and substrate 102, and such devices are referred to as “bottom emitters”. It is also possible to construct a device that passes through the cathode emission, for example, by keeping the thickness of the cathode layer 11 小 less than 50 mm to 100 mm so that the cathode is substantially transparent. The organic LED can be deposited on a matrix pixel substrate to form a monochromatic or multi-color pixelated display. A multi-color display can be constructed using red, green, and blue emission pixel groups. In such displays, individual elements are typically addressed by initiating a column (or row) line to select pixels, and column (or row) pixels are written to individual elements to produce a display. A so-called active matrix display has a memory component associated with each pixel, the memory component is typically a storage capacitor and a transistor, and the passive matrix display does not have this memory component, but is instead repeatedly scanned 'It's a bit similar to a TV image' to give an impression of a stable image. Figure lb shows a cross section through a passive matrix display 15 ,, wherein the elements similar to those in Figure la are denoted by the same reference numerals. In the passive matrix display 150, the electroluminescent layer 1 〇 8 includes a plurality of pixels 152, and the cathode layer 11 〇 includes a plurality of mutually electrically insulated conductive lines, and the conductive lines 154 are wired into the page of FIG. The lines each have an associated contact 156. Similarly, the indium tin oxide anode layer 1 〇 4 also includes a plurality of anode lines, of which only one anode line is shown in Figure lb, and the anode line is routed at right angles to the cathode line. Contacts for each anode line are also provided (not 141682.doc 201013618 not shown in Figure lb). An electroluminescent pixel 152 at the intersection of the cathode line and the anode line can be addressed by applying a voltage between the associated anode and cathode lines.
現在參考圖2a，圖中概念上繪示用於於圖lb繪示之類型 之一被動式矩陣OLED顯示器15〇之一驅動配置。提供複數 個恆定電流產生器200，各恆定電流產生器連接至一電源 線202及連接至複數個行線2〇4中之一者，為清晰起見圖中 僅繪不一行線。亦提供複數個列線206(圖中僅繪示一列 線），且彼等列線之各者可藉由一切換式連接21〇而被選擇 地連接至一接地線208。如圖所示，在線2〇2上具有一正電 源電壓，行線204包括陽極連接丨5 8，且列線2〇6包括陰極 連接1 54，然而當電源線2〇2相對於接地線2〇8係負時，該 等連接將逆轉。 如繪示，該顯示器之像素212具有被施加至該像素的電 力且因此被照明。$ 了建立_影像，依次啟動該等行線之 各者直到完整列被定址時，保持用於一列之連接21〇,然 後選擇下一個列，重複處理程序。替代做法為，可選擇一 列且所有行被並行寫人（即，選擇—列且—電流被同時驅 動至該等行線之各者t )，卩同時以-所要亮度照明一列 中的像素。儘管後一配置需要更多行驅動電路，然而該後 配置係較佳，因為其允許一較迅速刷新每一像素。在一 =步替代配置中行中之各像素可在下—行被定址之 前被依次定址’然:而，由於尤其如下文所述之行電容的影 響，所以其通常不是較佳的。應瞭解，在圖2a中之配置 141682.doc -5^ 201013618 中，行驅動電路之功能與列驅動電路之功能可被互換。 通常提供一電流控制驅動（而非電壓控制驅動）給一 OLED，此係因為一 〇LED之亮度係藉由穿過其之電流而決 定的’因此決定其輸出之光子數量。在一電壓控制組態 中，亮度可橫跨一顯示器區域變化且隨著時間、溫.度及老 化變化，使得在一給定電壓驅動下，難以預測一像素將以 何種亮度呈現。在-彩色顯示器中，顏色呈現之準確性亦 可受到影響。 圖2b至圖2d分別繪示，施加至一像素之電流驅動22〇、 橫跨像素之電壓222，及當該像素被定址時隨著時間226推 移之來自該像素之光輸出224。含有該像素之列被定址， 且同時由虛線228表示之電流被驅動至該像素之行線上。 該行線（及像素）具有一相關聯電容，並且因此電壓逐漸升 高至一最大值23 0。該像素直到達到一點2 3 2才開始發射 光，在該點232上橫跨該像素之電壓大於該〇LED二極體之 壓降。相似地，在時間234，當該驅動電流關閉時，電壓 及光輸出隨著行電容放電而逐漸衰變。在同時寫入一列中 的所有像素之情況下（即在所有行被並行驅動之情況下）， 介於時間228與234之間之時間間隔對應於一線掃描週期。 圖3繪示被動式矩陣OLED顯示器之通用驅動電路之示意圖 3 〇〇。該OLED顯示器係藉由虛線3〇2表示且其包括複數（n) 個列線304及複數（n)個行線308，各列線具有-相應電極接 點3〇8，行線具有複數個對應行電極接點31〇 ^ 一 〇led連 接於各對列線與行線之間，在所繪示之配置中，〇LED之 141682.doc -6 - 201013618 其陽極連接至行線。一y驅動器314用一恆定電流驅動該等 行線308，一 X驅動器316驅動該列線3〇4，選擇性地連接該 等列線至接地。該y驅動器314及該X驅動器316兩者典型在 一處理器318控制之下。一電源供應器32〇提供電力到電 路’且特定言之，提供電力到y驅動器314。 圖4繪示一被動式矩陣OLED顯示器（諸如繪示於圖3之顯 示器302)之一行線之一電流驅動器4〇2之主要特徵。典型 地’一行驅動積體電路（諸如繪示於圖3之y驅動器314)尹提 供複數個此類電流驅動器，以驅動複數個被動式矩陣顯示 器行電極。 圖4中之該電流驅動器4〇2描述此電路之主要特徵的略圖 且包括一電流驅動器區塊406，該電流驅動器區塊併入一 雙極電晶體416，該雙極電晶體416具有一射極終端，該射 極終端大體上直接連接至處於電源電壓％之一電源供應線 4〇4。（此非必然要求應藉由最直接路線連接該射極終湍至 一電源線或該驅動器之一終端，而是較佳應無介入組件， 惟介於該射極與一電源供應軌之間驅動器電路内軌迹或連 接之固有電阻除外）。一行驅動輸出408通常經由一列驅動 器MOS切換器（未繪示於圖4)提供一電流驅動給〇led 412, OLED 412亦具有一接地連接414。一電流控制輪入 410被^供給電流驅動器區塊4〇6，且為圖解說明目的，圖 中繪示電流控制輸入410被連接至電晶體416之基極，然而 實務中一電流鏡像配置較佳。在電流控制線41〇上之信號 可包括一電壓或一電流信號。在電流驅動器區塊4〇6提供 141682.doc 201013618 可變可控式電流源之情況下，各電流驅動器區塊可介接 於且受控於來自一數位類比轉換器之一類比輸出。此類可 控電流源可提供一可變亮度或灰階顯示。改變像素亮度之 其他方法包含使用脈衝寬度調變（PWM)準時改變像素。在 一 PWM方案中，一像素完全開啟或者完全關閉，但是一像 素之表觀亮度由於觀察者眼睛内之時間積分而變化。 持續需要可改戍OLED顯示器之壽命之驅動器方案。特 別需要適用於被動式顯示器之技術，此係因為製造被動式 顯不器比製造主動式顯示器更便宜。減小〇LED之驅動位 準（且因此免度）可顯著&尚器件壽命，例如減半〇Le 〇之 驅動/亮度可使其哥命增加大約一因數4。在w〇 2006 035246、WO 2006 035247及评〇 2006 〇35248(彼等案之内 容以引用的方式併入本文）中，申請人意識到，一種解決 方案在於，採用多線定址技術以減小峰值顯示器驅動位 準，特定言之，在被動式矩陣OLED顯示器中，並且因此 增加該顯示器之壽命。從廣義上而言，此等方法包括使用 一第一組行驅動信號驅動OLED顯示器之複數個行電極， 同時使用一第一組列驅動信號驅動顯示器之兩個或兩個以 上列電極；然後使用一第二組行驅動信號驅動行電極，同 時使用一第二組列驅動信號驅動兩個或兩個以上列電極。 較佳地，該等列驅動信號及行驅動信號包括來自一大體恆 定電流產生器（諸如一電流源或電流儲集器）之電流驅動信 號。較佳地，此類電流產生器係可控或可程式化，例如， 使用一數位類比轉換器。 141682.doc 201013618 驅動一行同時驅動兩個或兩個以上列之效應係，依藉由 列驅動信號所決定之比例，在兩個或兩個以上列之間劃分 行驅動；換言之，對於一電流驅動，依藉由列驅動信號之 相對值或比例所決疋之比例，在兩個或兩個以上列之間割 分行驅動，在兩個或兩個以上列之間劃分一行中之電流。 從廣義上而言，此允許在多線掃描週期中建立一列像素或 線像素之光度分佈，因此有效率減少0LED像素之峰值亮 度，於是增加顯示器中之像素之壽命。運用一電流驅動二 憑藉至像素之連續驅動信號之大體上線性總和，而獲得像 素之所要光度。 【發明内容】 因此，本發明係、關於改良（特定言之卜被動式矩陣 oled顯示器之效率。有利的係’本發明亦相容於多線定 址技術。 一如上討論之最簡單形式之電流產生電路包括—電流躁及 一電流儲集器。例如’如圖3所示，行y驅動器314可被切 J疋：電流源，且列x驅動器316可被認為是1流諸集 器’然而如熟悉此項技術者所瞭解，功能可被逆轉。 -電流w或源電流Is 一是否匹配取決於 徵及操作參數(諸如電壓位準)之多個因素：：體特 匹配的驅動器係引起顯示器中條紋的原因，例％ ’不 之驅動相比於鄰近行困難的多。隨著時 ’個別行 的驅動器可漂移朝向匹配條件，通常在_最：不'配 若不需要此-最大電壓位準t壓位準。 位丰，則此-匹配條件可浪費電力 141682.doc 201013618 且亦會對OLED顯示器之壽命不利。 根據本發明之-第-態樣，提供—種於—被動式矩陣驅 動發射式顯示器中平衡一共模電壓之方法，該方法包含： 使用一第一組行驅動信號驅動一第一組行電極，且使用一 第一組列驅動信號驅動一第一組列電極；監测橫跨該第一 組行電極或該第一組列電極之各者之一共模電壓，且比較 該所監測之共模電壓與一臨限值；將該等所監測之共模電 壓求和，同時排除對該臨限值之一特定偏差的列電極或行 電極求和；比較該經求和之共模電壓與一參考電壓；及調 整該第一組行驅動信號或該第一組列驅動信號使得該經 求和之共模電壓接近該第二參考電壓。 較佳地，排除包括：停用該被排除之列電極或行電極所 連接的一列驅動器或行驅動器之一啟用輸入。 該特定偏差較佳低於該臨限值。 較佳地，求和包含：決定一橫跨該求和電極之平均電 壓。 較佳地’比較該經求和之共模電壓與一參考電壓包含· 產生一 ^说以指示出該經求和共模電壓是否高於或低於該 參考電壓。更較佳地，該產生之信號係一單一位元。 一列驅動信號或行驅動信號係藉由一驅動處理器根據一 參考控制電流而予以控制，且調整包含傳達一信號至該驅 動處理器及調整該參考控制電流。 較佳地’該方法包含：使用該第一組行驅動信號驅動該 顯示器之該等行電極，同時使用該第一組列驅動信號驅動 141682.doc • 10· 201013618 該顯示器之兩個或兩個以上列電極；然後使用該第二組行 驅動信號驅動該等行電極’同時使用一第二組列驅動信號 驅動兩個或兩個以上列電極。 較佳地，該等第一與第二行驅動信號及該等第一與第二 列驅動信號經選擇使得藉由該等列及行電極驅動之該顯示 器中之像素之一所要光度係藉由從該等第一列驅動信號與 第一行驅動信號決定之光度及從該等第二列驅動信號與第 二行驅動信號決定之光度之一大體線性光度總和而獲得。 較佳地，該發射式顯示器包括由一有機電致發光材料組 成之像素。 本發明之實施例現將僅以範例的方式及參考附加圖式來 說明。 【實施方式】 圖5中，一被動式矩陣〇led顯示器（相似於參考圖3描述 之被動式矩陣OLED顯示器）具有藉由列驅動電路512驅動 之列電極3 06及藉由行驅動器51〇驅動之行電極31〇。於圖6 繪示根據本發明之列驅動電路512之進一步細節。行驅動 器510具有一行資料輸入5〇9’用於設定至一或多個行電極 的電流驅動；相似地，列驅動器512具有一列資料輸入 511用於δ又疋至兩個或兩個以上列的電流驅動比率。輸 入509及511且係數位輸入以易於介接；行資料輸入5〇9宜 設定顯示器302中之所有瓜行的電流驅動。 一資料控制匯流排502(其可為串列或並行）上提供用於 顯不器之貝料。匯流排5〇2提供一輸入至一圖框儲存記憶 體503 ’其中記憶體5G3儲存顯示器之各像素的光度資料， 141682.doc •11 · 201013618 或在一彩色顯不器中，記憶體503儲存各子像素的光度資 訊（其可被編碼為獨立RGB彩色信號，或編碼為光度信號 或色度仏號’或依其他方式）。儲存在圖框記憶體5〇3中之 資料決定顯不器之各像素（或子像素）之一所要表觀亮度， 且一顯不器驅動處理器506可憑藉第二讀取匯流排5〇5讀出 此資訊（在實施例中，可省略匯流排5〇5，且作為替代地使 用匯流排502)。 可完全以硬體實施顯示器驅動處理器5〇6，或使用（例 如）一數位信號處理核心以軟體實施顯示器驅動處理器 506，或以硬體與軟體之組合實施顯示器驅動處理器5〇6， 例如，使用專用硬體以加速矩陣操作。然而，一般而言， 將至少部分地憑藉儲存在一程式記憶體5〇7中之經儲存程 式碼或微碼來實施顯示器驅動處理器5〇6,顯示器驅動處 理器506在一時脈508控制下且結合工作記憶體5〇4操作。 可在一貝料載體或可抽換式儲存器5〇7a上提供程式記憶體 5 07中之程式碼。 程式§己憶體507中之程式碼經組態以使用習知程式化技 術來實施一或多種多線定址方法。在一些實施例中，可藉 由使用一標準數位信號處理器及依一習知程式發展語言執 行之程式碼來實施此等方法。在此一實例中，例如，可採用 一習知DSP常式之程式庫，以實施奇異值分解法（singuiar value decomposition ; SVD)，或可撰寫用於此目的的專用 程式碼，或可實施不採用SVD之其他實施例，諸如以上描 述之關於驅動彩色顯示器之技術。 參考圖6，根據本發明中之一實施例之一列驅動器6〇〇之 141682.doc •12- 201013618 一示意圖包括可連接至列資料輸入511的複數個列電極306 之各者。該複數個列電極306之各者進一步連接至一高值 電阻器602 ’其中提供的高值電阻器602之數量匹配列電極 306之數量。各咼值電阻器602及相應地各列電極3〇6亦連 接至一共同節點604，共同節點604係透過參考電阻器6〇8 連接至一參考電壓產生器6〇6。 跨參考電阻器608連接一比較器610，比較器61〇具有連 接於參考電阻器608與共同節點604之間的一正輸入終端及 ® 連接於參考電阻器608與參考電壓產生器606之間之一負輸 入終端。比較器610之一輸出終端連接至一數位控制器 612，數位控制器612包括一校正邏輯模組614、一校正查 詢表616、一校正内插器618及一後處理模組62〇。 在操作中，在共同節點6〇4處提供受驅動列電極之平 均列電壓。若受驅動列電極3〇6之平均列電壓係高於藉由 參考電壓產生器606產生之一參考電塵，則一電流流入至 a同節點604中且流出參考電壓產生器606。若受驅動列電 極306之平均列電壓係低於藉由參考電壓產生器產生之 參考電壓’則-電流從參考電壓產生器606流出朝向共 同節點604。 八 ”藉由比較器610偵測電流，比較器61〇係可操作以輸出一 單一位元，以：士山企^ 夺日不出又驅動列電極3〇6之平均列電壓是否 高於或低於參考雷嚴。 〒電壓该單一位元被傳達給數位控钊器 612且被用於調整一 金列參考電流以用於後續圖框。一！接 收到該單一位开，田 用^就通知數位控制器612採用校i邏 141682.doc -13- 201013618 輯模組614進行校正邏輯，以調整列參考電流Iref。一校正 查詢表616提供用於‘調整的決定值，取決於需求，隨後 逐步調升或逐步調降iref。 在-些情況下，-替代配置對於搭配本發明第二實施例 中指述之配置係較佳的。例如，所有列電極可被程式化到 -定電流，但是特定行可暫時被關閉或消隱。在此等消隱 ㈣’不再具有「拉上」行電流之個別列通常迅速降至接 地。當此發生時’求和電㈣受驅動列電極（包含迅逮降 至接地之列電極)之平均列電壓。結果，誤差被引入至共 模電壓比較器之求和點中。 a 為阻止此誤差出現’參考圖7，本發明之—第三實施例 700在列電極306之各者上提供一比較器7〇2。在操作中， 比較器702監測列電極3〇6之各者上的列共模電壓以決定 其是否衰變低於-定參考電壓ϋ較器搬觀察到共 模電壓低於參考電壓，則一列啟用切換器7〇4可停用列電 極電流以防被包含於求和電壓中。 啟用列電極電流及停用列電極電流以防被包含於求和電 壓的功能係自動的且不需要經由行電極DAC控制及調節整 體共模電壓之-共模控制電路的介入。必匕冑免需要所有n 個個別列電極之個別控制，且因此減小列電極控制之額外 耗用。 毋庸置疑熟習此項技術者可想出許多其他有效替代物。 應瞭解本發明不受限於被描述之實施例且包含熟習此技術者 所瞭解之處於附在此處之請求項之精神及範圍内之修改。 141682.doc -14- 201013618 【圖式簡單說明】 圖la及圖lb分別繪示有機發光二極體及被動式矩陣 OLED顯示器之橫截面； 圖2a到圖2d分別繪示被動式矩陣OLED顯示器之概念驅 動器配置、顯示器像素之驅動電流對時間圖表、像素電壓 對時間圖表，及像素光輸出對時間圖表； 圖3螬示根據先前技術之被動式矩陣〇led顯示器之通用 驅動器電路之示意圖； 圖4繪示被動式矩陣OLED顯示器驅動器之方塊圖； 圖5係根據本發明之第一實施例之被動式矩陣驅動〇led 顯示器之示意圖； 圖6係根據本發明之第二實施例之列驅動器之示意圖；及 圖7係根據本發明之第三實施例之列驅動器之示意圖。 【主要元件符號說明】 100 有機LED之基本結構 102 基板 104 陽極傳輸層 106 電洞傳輪層 108 電致發光層 110 陰極層 114 接觸導線 116 接觸導線 118 電源 120 光 141682.doc •15- 201013618 150 被動式矩陣顯示器 152 像素 154 相互電絕緣傳導線/陰極連接 156 節點 158 陽極線/陽極連接 200 恆定電流產生器 202 饋電線 204 行線 206 列線 208 接地線 210 切換式連接 302 虛線 304 列線 306 列電極 308 行線/列電極接點 310 行電極接點 314 行y驅動器/y驅動器 316 列X驅動器/χ驅動器 320 電源供應益 402 電流驅動器 404 電源供應線 406 電流驅動益區塊 408 行驅動輸出 410 電流控制線 141682.doc -16- 201013618 412 有機發光二極體 502 資料控制匯流排 503 圖框儲存記憶體 504 工作記憶體 506 顯示器驅動處理器 507 程式記憶體 508 時脈 509 行資料輸入Referring now to Figure 2a, a one-drive configuration of one of the passive matrix OLED displays of the type illustrated in Figure lb is conceptually illustrated. A plurality of constant current generators 200 are provided. Each of the constant current generators is coupled to a power supply line 202 and to one of a plurality of line lines 2〇4. For clarity, only one line is drawn. A plurality of column lines 206 are also provided (only one column is shown), and each of the column lines can be selectively connected to a ground line 208 by a switched connection 21A. As shown, there is a positive supply voltage on line 2〇2, row line 204 includes anode connection 丨5 8, and column line 2〇6 includes cathode connection 1 54. However, when power line 2〇2 is relative to ground line 2 When 〇8 is negative, the connections will be reversed. As shown, the pixel 212 of the display has power applied to the pixel and is thus illuminated. $Build_image, start each of the row lines in turn until the full column is addressed, keep the connection for one column 21〇, then select the next column and repeat the processing. Alternatively, a column can be selected and all rows are written in parallel (i.e., select-column and - current is simultaneously driven to each of the row lines), while simultaneously illuminating the pixels in a column with the desired brightness. Although the latter configuration requires more row drive circuitry, the post configuration is preferred because it allows for a faster refresh of each pixel. In a = step alternative configuration, each pixel in the row can be addressed sequentially before the lower row is addressed. However, it is generally not preferred due to the effects of row capacitance, particularly as described below. It should be understood that the function of the row driver circuit and the function of the column driver circuit can be interchanged in the configuration 141682.doc -5^ 201013618 in Fig. 2a. A current controlled drive (rather than a voltage controlled drive) is typically provided to an OLED because the brightness of an LED is determined by the current passing through it, thus determining the number of photons it outputs. In a voltage controlled configuration, the brightness can vary across a display area and varies with time, temperature, and aging, making it difficult to predict at what brightness a pixel will be rendered at a given voltage. In a color display, the accuracy of color presentation can also be affected. 2b through 2d respectively illustrate the current drive 22 施加 applied to a pixel, the voltage 222 across the pixel, and the light output 224 from the pixel as the pixel is addressed as time 226 is shifted. The column containing the pixel is addressed, and the current indicated by dashed line 228 is driven to the row of the pixel. The row line (and pixel) has an associated capacitance, and thus the voltage gradually rises to a maximum value of 230. The pixel does not begin to emit light until it reaches a point 232, at which point the voltage across the pixel is greater than the voltage drop of the 〇LED diode. Similarly, at time 234, when the drive current is turned off, the voltage and light output gradually decay as the row capacitance discharges. In the case where all pixels in one column are simultaneously written (i.e., in the case where all rows are driven in parallel), the time interval between times 228 and 234 corresponds to a one-line scanning period. 3 is a schematic diagram of a general-purpose driving circuit of a passive matrix OLED display. The OLED display is represented by a dashed line 3〇2 and includes a plurality (n) of column lines 304 and a plurality of (n) row lines 308, each column line having a corresponding electrode contact 3〇8, the row line having a plurality of Corresponding row electrode contacts 31 〇 ^ 〇 led connected between each pair of column lines and row lines, in the illustrated configuration, 〇 LED 141682.doc -6 - 201013618 its anode is connected to the row line. A y driver 314 drives the row lines 308 with a constant current, and an X driver 316 drives the column lines 3〇4 to selectively connect the column lines to ground. Both the y driver 314 and the X driver 316 are typically under the control of a processor 318. A power supply 32 〇 provides power to the circuit 'and, in particular, provides power to the y driver 314. 4 illustrates the main features of a current driver 4〇2 of one of the row lines of a passive matrix OLED display (such as the display 302 shown in FIG. 3). Typically, a row of driver integrated circuits (such as y driver 314 shown in Figure 3) provides a plurality of such current drivers to drive a plurality of passive matrix display row electrodes. The current driver 4〇2 of FIG. 4 depicts a schematic of the main features of the circuit and includes a current driver block 406 that incorporates a bipolar transistor 416 having a shot. The pole terminal is substantially directly connected to one of the power supply voltages 4 〇 4 at a power supply voltage %. (This does not necessarily require that the emitter terminal be connected to a power line or one of the terminals of the driver by the most direct route, but preferably there should be no intervening components, but between the emitter and a power supply rail Except for the inherent resistance of the trace or connection within the driver circuit). A row of driver outputs 408 typically provides a current drive to 〇led 412 via a column of driver MOS switches (not shown in FIG. 4), which also has a ground connection 414. A current control wheel 410 is supplied to the current driver block 4〇6, and for illustrative purposes, the current control input 410 is coupled to the base of the transistor 416, but in practice a current mirror configuration is preferred. . The signal on current control line 41 can include a voltage or a current signal. In the case where the current driver block 4〇6 provides a 141682.doc 201013618 variable controllable current source, each current driver block can be interfaced to and controlled by an analog output from a digital analog converter. Such a controllable current source provides a variable brightness or gray scale display. Other methods of changing pixel brightness include using pulse width modulation (PWM) to change pixels on time. In a PWM scheme, a pixel is fully on or off completely, but the apparent brightness of a pixel varies due to time integration within the observer's eye. There is a continuing need for a driver solution that can change the life of an OLED display. In particular, there is a need for a technology suitable for passive displays, since manufacturing passive displays is less expensive than manufacturing active displays. Reducing the drive level of the 〇LED (and thus the degree of freedom) can significantly reduce the device lifetime, for example, by reducing the drive/brightness of Le 〇Le 〇 to increase its sacredness by a factor of four. In WO 2006 035246, WO 2006 035247, and cit. 2006 〇35248 (the contents of each of which are hereby incorporated by reference), the Applics <RTIgt;</RTI> Display drive levels, in particular, in passive matrix OLED displays, and thus increase the lifetime of the display. Broadly speaking, the methods include driving a plurality of row electrodes of the OLED display using a first set of row drive signals while simultaneously driving two or more column electrodes of the display using a first set of column drive signals; A second set of row drive signals drives the row electrodes while simultaneously driving two or more column electrodes using a second set of column drive signals. Preferably, the column drive signals and the row drive signals comprise current drive signals from a substantially constant current generator, such as a current source or current collector. Preferably, such current generators are controllable or programmable, for example, using a digital analog converter. 141682.doc 201013618 Driving a row to drive two or more columns of effect systems simultaneously, dividing the row drive between two or more columns by the ratio determined by the column drive signal; in other words, for a current drive By dividing the row drive between two or more columns by dividing the relative value or ratio of the column drive signals, the current in one row is divided between two or more columns. In a broad sense, this allows for the luminosity distribution of a column of pixels or line pixels to be established in a multi-line scan period, thus effectively reducing the peak brightness of the OLED pixels, thus increasing the lifetime of the pixels in the display. The luminosity of the pixel is obtained by using a current drive 2 to obtain a substantially linear sum of the continuous drive signals to the pixels. SUMMARY OF THE INVENTION Accordingly, the present invention is directed to an improvement (specifically, the efficiency of a passive matrix OLED display. Advantageously, the present invention is also compatible with multi-line addressing techniques. The simplest form of current generation circuit as discussed above Including - current 躁 and a current collector. For example, as shown in FIG. 3, row y driver 314 can be cut: current source, and column x driver 316 can be considered as a stream collector. As understood by the skilled artisan, the function can be reversed. - Whether the current w or the source current Is a match depends on a number of factors that cite operational parameters (such as voltage levels): the body-matched driver causes the stripes in the display The reason, the example % 'no drive is more difficult than the adjacent row. With time 'the individual row of the driver can drift towards the matching condition, usually in the _ most: not equipped with this - the maximum voltage level t The level of pressure. If this is the case, the matching condition can waste power 141682.doc 201013618 and it will also be detrimental to the life of the OLED display. According to the first aspect of the present invention, the passive matrix drive is provided. A method of balancing a common mode voltage in an emissive display, the method comprising: driving a first set of row electrodes using a first set of row drive signals, and driving a first set of column electrodes using a first set of column drive signals; monitoring A common mode voltage across one of the first set of row electrodes or the first set of column electrodes, and comparing the monitored common mode voltage to a threshold value; summing the monitored common mode voltages, Simultaneously eliminating the sum of the column or row electrodes of a particular deviation of the threshold; comparing the summed common mode voltage to a reference voltage; and adjusting the first set of row drive signals or the first set of column drives The signal causes the summed common mode voltage to be close to the second reference voltage. Preferably, excluding includes deactivating one of the column of row drivers or row drivers to which the excluded column or row electrode is connected. Preferably, the summation comprises: determining an average voltage across the summing electrode. Preferably comparing 'the summed common mode voltage with a reference voltage comprising · generating One ^ said to It is shown whether the summed common mode voltage is higher or lower than the reference voltage. More preferably, the generated signal is a single bit. A column of driving signals or row driving signals is controlled by a driving processor according to Controlling the control current, and adjusting includes transmitting a signal to the driver processor and adjusting the reference control current. Preferably, the method includes: driving the row electrodes of the display using the first set of row drive signals, Simultaneously using the first set of column drive signals to drive 141682.doc • 10· 201013618 two or more column electrodes of the display; then using the second set of row drive signals to drive the row electrodes 'while using a second set The column drive signal drives two or more column electrodes. Preferably, the first and second row drive signals and the first and second column drive signals are selected to be driven by the columns and row electrodes The luminosity of one of the pixels in the display is determined by the luminosity determined from the first column of driving signals and the first row of driving signals and the second row of driving signals and the second row One of the luminance motion signal determines the sum of brightness obtained substantially linear. Preferably, the emissive display comprises a pixel comprised of an organic electroluminescent material. Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings. [Embodiment] In FIG. 5, a passive matrix 〇led display (similar to the passive matrix OLED display described with reference to FIG. 3) has a column electrode 306 driven by the column driving circuit 512 and a row driven by the row driver 51 〇 The electrode 31 is 〇. Further details of the column driver circuit 512 in accordance with the present invention are illustrated in FIG. Row driver 510 has a row of data inputs 5〇9' for current drive to one or more row electrodes; similarly, column driver 512 has a column of data inputs 511 for δ and 疋 to two or more columns. Current drive ratio. Inputs 509 and 511 and the coefficient bit input is easy to interface; the line data input 5〇9 should set the current drive of all the meridians in the display 302. A material control bus 502 (which may be in series or in parallel) is provided for the beaker of the display. The bus bar 5〇2 provides an input to a frame storage memory 503 'where the memory 5G3 stores the photometric data of each pixel of the display, 141682.doc •11 · 201013618 or in a color display, the memory 503 is stored Photometric information for each sub-pixel (which can be encoded as an independent RGB color signal, or encoded as a photometric signal or a chrominance apostrophe' or otherwise). The data stored in the frame memory 5〇3 determines the apparent brightness of one of the pixels (or sub-pixels) of the display, and a display driver processor 506 can rely on the second read bus 5〇. 5 This information is read (in the embodiment, the bus bar 5〇5 may be omitted and the bus bar 502 is used instead). The display drive processor 〇6 may be implemented entirely in hardware, or the display drive processor 506 may be implemented in software using, for example, a digital signal processing core, or the display drive processor 〇6 may be implemented in a combination of hardware and software, For example, use dedicated hardware to speed up matrix operations. However, in general, the display driver processor 5〇6 will be implemented, at least in part, by the stored code or microcode stored in a program memory 5〇7, which is controlled by a clock 508 And combined with working memory 5〇4 operation. The code in the program memory 507 can be provided on a batten carrier or removable storage 5〇7a. The code in program 507 is configured to implement one or more multi-line addressing methods using conventional stylized techniques. In some embodiments, such methods may be implemented by using a standard digital signal processor and a code implemented in a language-implemented language development language. In this example, for example, a conventional DSP routine library can be used to implement singuiar value decomposition (SVD), or a dedicated code for this purpose can be written, or can be implemented. Other embodiments of SVD are employed, such as the techniques described above for driving a color display. Referring to Figure 6, a column driver 6 141682.doc • 12- 201013618 in accordance with one embodiment of the present invention includes a plurality of column electrodes 306 connectable to column data input 511. Each of the plurality of column electrodes 306 is further coupled to a high value resistor 602' wherein the number of high value resistors 602 provided matches the number of column electrodes 306. Each of the threshold resistors 602 and corresponding column electrodes 3〇6 are also coupled to a common node 604 which is coupled to a reference voltage generator 6〇6 via a reference resistor 6〇8. A comparator 610 is coupled across the reference resistor 608. The comparator 61 has a positive input terminal connected between the reference resistor 608 and the common node 604 and is connected between the reference resistor 608 and the reference voltage generator 606. A negative input terminal. An output terminal of comparator 610 is coupled to a digital controller 612. The digital controller 612 includes a correction logic module 614, a calibration query table 616, a calibration interpolator 618, and a post processing module 62. In operation, the average column voltage of the driven column electrodes is provided at a common node 6〇4. If the average column voltage of the driven column electrodes 3〇6 is higher than one of the reference electrodes generated by the reference voltage generator 606, a current flows into the a-node 604 and flows out of the reference voltage generator 606. If the average column voltage of the driven column electrode 306 is lower than the reference voltage generated by the reference voltage generator, the current flows from the reference voltage generator 606 toward the common node 604. The comparator 61 detects the current, and the comparator 61 is operable to output a single bit to: whether the average column voltage of the column electrode 3〇6 is higher than or after the Shishan enterprise Below the reference Thunder. The single bit is transmitted to the digital controller 612 and is used to adjust a gold column reference current for subsequent frames. One! After receiving the single bit, the field uses ^ The notification digital controller 612 performs correction logic to adjust the column reference current Iref using the calibration logic 141682.doc -13 - 201013618 module 614. A calibration lookup table 616 provides the decision value for the adjustment, depending on the demand, followed by The iref is stepped up or down gradually. In some cases, the alternative configuration is preferred for the configuration described in the second embodiment of the invention. For example, all column electrodes can be programmed to a constant current, but Certain lines can be temporarily turned off or blanked. In this case, blanking (4) 'individual columns that no longer have "pull" line currents usually fall quickly to ground. When this occurs, the summation (4) is the average column voltage of the driven column electrode (which includes the electrode that is quickly dropped to ground). As a result, the error is introduced into the summing junction of the common mode voltage comparator. a To prevent this error from occurring' Referring to Figure 7, a third embodiment 700 of the present invention provides a comparator 7〇2 on each of the column electrodes 306. In operation, comparator 702 monitors the column common mode voltage on each of column electrodes 3〇6 to determine if it decays below a predetermined reference voltage, and the column is enabled to observe that the common mode voltage is lower than the reference voltage. The switch 7〇4 can disable the column electrode current from being included in the summing voltage. The column electrode current is enabled and the column electrode current is disabled to prevent the intervention of the common mode control circuit that is automatically included in the function of the summing voltage and that does not require control and regulation of the overall common mode voltage via the row electrode DAC. Individual control of all n individual column electrodes is required to be eliminated, and thus the additional consumption of column electrode control is reduced. There is no doubt that many other effective alternatives can be imagined by those skilled in the art. It is to be understood that the invention is not to be construed as being limited by the descriptions 141682.doc -14- 201013618 [Simple diagram of the diagram] Figures la and lb show the cross section of the organic light emitting diode and the passive matrix OLED display respectively; Fig. 2a to Fig. 2d respectively show the conceptual driver of the passive matrix OLED display Configuration, display pixel drive current versus time graph, pixel voltage vs. time graph, and pixel light output versus time graph; FIG. 3 is a schematic diagram of a universal driver circuit of a passive matrix 〇led display according to the prior art; FIG. Figure 5 is a block diagram of a passive matrix driven 〇led display according to a first embodiment of the present invention; Figure 6 is a schematic view of a column driver according to a second embodiment of the present invention; and Figure 7 A schematic diagram of a column driver in accordance with a third embodiment of the present invention. [Main component symbol description] 100 Basic structure of organic LED 102 Substrate 104 Anode transport layer 106 Electrode transfer layer 108 Electroluminescent layer 110 Cathode layer 114 Contact wire 116 Contact wire 118 Power supply 120 Light 141682.doc •15- 201013618 150 Passive matrix display 152 pixels 154 electrically insulated conductive wire / cathode connection 156 node 158 anode wire / anode connection 200 constant current generator 202 feeder 204 row line 206 column line 208 ground line 210 switching connection 302 dotted line 304 column line 306 column Electrode 308 Row Line/Column Electrode Contact 310 Row Electrode Contact 314 Row y Driver / y Driver 316 Column X Driver / χ Driver 320 Power Supply Benefit 402 Current Driver 404 Power Supply Line 406 Current Drive Benefit Block 408 Row Drive Output 410 Current Control Line 141682.doc -16- 201013618 412 Organic Light Emitting Diode 502 Data Control Bus 503 Picture Storage Memory 504 Working Memory 506 Display Driver Processor 507 Program Memory 508 Clock 509 Line Data Input
510 行驅動器 511 列資料輸入 512 列驅動器電路 600 列驅動器 602 高值電阻器 604 共同節點 606 參考電壓產生器 608 參考電阻器 610 比較器 612 數位控制器 614 校正邏輯模組 616 校正查詢表 618 校正内插器 620 後處理模組 702 比較器 704 列啟用切換器 141682.doc -17-510 Row Driver 511 Column Data Input 512 Column Driver Circuit 600 Column Driver 602 High Value Resistor 604 Common Node 606 Reference Voltage Generator 608 Reference Resistor 610 Comparator 612 Digital Controller 614 Correction Logic Module 616 Calibration Query Table 618 Correction Interpolator 620 Post-Processing Module 702 Comparator 704 Column Enable Switcher 141682.doc -17-