201013622 九、發明說明： 【發明所屬之技術領域】 本發明係有關一種背光（backlight)控制，特別是一 種使用驅動加速（overdrive)查詢表（lookup table)之 背光控制系統及方法。 φ 【先前技術】 背光控制係用以從背面或侧面來照亮平面顯示器（例 如液晶顯示器）的一種技術。光源可以是冷陰極管 (CCFL)、發光二择體（LED)或其他光源。 固定式背光不管影像資料或週邊光線如何變化都會提 ❹供穩定固定的光線。固定式背光的最大缺點為不良的動態 對比特性。為了增加其對比，必須使用動態背光（dynamic backlight，DBL)技術’其動態地或適應性地（) 根據影像資料的分佈情形以調整整體或某特定部分的背光 亮度。 然而’-般的冷陰極管具有反應較慢的特性。換句話 說’冷陰極管需要-段時間才能達到目標亮度；因此，背 201013622 光的亮度改變通常會落後於背光驅動信號（例如脈寬調變 (PWM)工作週期（duty)訊號）的改變。若要解決上述 反應慢之問題，必須使用特殊之快速但昂責之冷陰極管來 置換一般便宜之冷陰極管。然而，此種解決方法對於大量 製造而言’若考量其成本及消費者接受度，將是不實際的。 鑑於傳統背光（特別是動態背光）不能有效地符合所 ❹要求的反應時間’因此，亟需提出-種新穎的動態背光控 制機制，使其具有較快的反應時間且不會犧牲其成本。 【發明内容】 根據上述’本發明的目的之一為提供一種背光控制系 統及方法，用以增快其反應時間且*會犧牲成本。 ❹ 根據本發月實施例，驅動力口速（〇verdrive)裝置根據 目前訊框之背光工作週期減與先前訊框之背光工作週期 訊號以更改背光工作週期訊號。在—實施例中 ，驅動加速 裝置包含_查詢表’其可經查詢而輸出得到該更改之背光 工作週期訊號。以1¾更改之f紅作週期訊號驅動背光以 發射光線至顯示面板，因而得以增快背光的反應速度。 6 201013622 【實施方式】 第一圖顯示本發明實施例之動態背光驅動加速 (overdrive )控制系統丄。第二圖顯示本發明實施例之動 .¾¾光驅動加速控制方法2的流程步驟。鑑於一般光源具 較慢的反應速度’例如冷陰極管（CCFL)、低速發光二極 II (LED)或其他低等級光源，本實施例因此使用驅動加 ❾速裝置10以加速背光控制系統1的整體反應時間。驅動 加速裝置10之實施可以為硬體電路、軟體程式或其組合。 在本實加例中，係以—查詢表（l〇〇kUp table )(如下表一） 來實施（步驟20) ’但是本發明並不限定於此。此驅動加 速查詢表係根據目前背光工作週期訊號（BLduty)及（儲 存於緩衝器12之）先前背光工作週期訊號，以輸出驅動 加速背光工作週期訊號（BLduty)。該背光工作週期訊號 ❹ （BL duty)可以為脈寬調變（pWM)訊號，其脈寬正比 於所需之背光照度》於表一當中，縱轴代表先前訊框 (frame)背光工作週期訊號，而橫轴則代表目前訊框背 光工作週期訊號。表一所示之值僅作為例示（而非限定） 一個八位元系統。表一當中的每一個值所對應的工作週期 (duty cycle )相當於，’值/255”。例如，表一當中的值”59” 即對應至23% (=59/255)之工作週期（例如背光脈寬調 變（PWM)工作週期）。 201013622 表一 前 先前 0 32 64 96 128 160 192 224 255 0 0 75 145 168 186 202 222 241 255 32 0 32 97 135 163 190 215 238 255 64 0 10 64 111 148 180 208 235 255 96 0 6 50 96 138 174 204 233 255 128 0 3 39 83 128 167 167 200 255 160 0 2 30 71 116 160 196 229 255 192 0 1 21 59 107 152 192 227 255 224 0 1 14 48 93 143 186 224 255 8 201013622 接著，比較目 作週期（步驟2ι β 牙光工作週期與先前訊框背光工 光週期作, 再由驅動加速查詢表得到驅動加速背 Ο 形，J：中M , 一圖例示背光工作週期訊號之反應波 ，、中N代表目 及 DN-i/DN/D，則代表d、°框，N_1代表先前訊框，而 框的背光工作调龙 光工作週期訊號的強度。如果先前訊 Dn.1<Dn)，則使^於目前訊樞的背光工作週期（亦即， 驅動加送背杏τ ^、 於預期Dn的較大強度D’N作為 前訊樞的背光工作(步驟_，如’如果先 期為”叱，由於”32，，<_，而目㈣框的背光工作週 馨201013622 IX. Description of the Invention: [Technical Field] The present invention relates to a backlight control, and more particularly to a backlight control system and method using an overdrive lookup table. φ [Prior Art] Backlight control is a technique used to illuminate a flat panel display (such as a liquid crystal display) from the back or side. The light source can be a cold cathode tube (CCFL), a light emitting diode (LED) or other light source. Fixed backlights provide stable, fixed light regardless of changes in image data or ambient light. The biggest drawback of fixed backlights is the poor dynamic contrast characteristics. In order to increase the contrast, dynamic backlight (DBL) technology must be used to dynamically or adaptively adjust the backlight brightness of the whole or a particular portion depending on the distribution of the image data. However, the cold cathode tube has a slow response characteristic. In other words, the cold cathode tube takes - some time to reach the target brightness; therefore, the brightness change of the back 201013622 light usually lags behind the change of the backlight drive signal (such as the pulse width modulation (PWM) duty signal). To solve the above problem of slow reaction, a special fast but rigorous cold cathode tube must be used to replace the generally inexpensive cold cathode tube. However, such a solution would be impractical for mass production to consider its cost and consumer acceptance. Since conventional backlights (especially dynamic backlights) do not effectively meet the required response times, there is a need for a novel dynamic backlight control mechanism that allows for faster reaction times without sacrificing cost. SUMMARY OF THE INVENTION One object of the present invention is to provide a backlight control system and method for increasing the response time and at the expense of cost. ❹ According to the embodiment of the present month, the driving speed (〇verdrive) device reduces the backlight duty cycle signal according to the backlight duty cycle of the current frame minus the backlight duty cycle signal of the previous frame. In an embodiment, the drive acceleration device includes a _ lookup table that can be queried to output the modified backlight duty cycle signal. The backlight is driven by a 13⁄4 modified f-cycle signal to emit light to the display panel, thereby increasing the response speed of the backlight. 6 201013622 [Embodiment] The first figure shows a dynamic backlight drive overdrive control system according to an embodiment of the present invention. The second figure shows the flow steps of the optical drive acceleration control method 2 of the embodiment of the present invention. In view of the slow response speed of a typical light source, such as a cold cathode tube (CCFL), a low speed light emitting diode (LED) or other low level light source, the present embodiment thus uses a drive plus idle device 10 to speed up the backlight control system 1. Overall reaction time. The implementation of the drive acceleration device 10 can be a hardware circuit, a software program, or a combination thereof. In the present embodiment, it is implemented by a query table (l〇〇kUp table) (see Table 1 below). However, the present invention is not limited thereto. The drive acceleration query table outputs an accelerated backlight duty cycle signal (BLduty) according to the current backlight duty cycle signal (BLduty) and the previous backlight duty cycle signal (stored in the buffer 12). The backlight duty cycle signal ❹ (BL duty) can be a pulse width modulation (pWM) signal, the pulse width is proportional to the required backlight illumination, and the vertical axis represents the previous frame backlight duty cycle signal. The horizontal axis represents the current frame backlight duty cycle signal. The values shown in Table 1 are for illustrative purposes only and are not intended to be an octet system. The duty cycle corresponding to each value in Table 1 is equivalent to 'value/255.' For example, the value "59" in Table 1 corresponds to a duty cycle of 23% (=59/255) ( For example, backlight pulse width modulation (PWM) duty cycle. 201013622 Table 1 previous 0 32 64 96 128 160 192 224 255 0 0 75 145 168 186 202 222 241 255 32 0 32 97 135 163 190 215 238 255 64 0 10 64 111 148 180 208 235 255 96 0 6 50 96 138 174 204 233 255 128 0 3 39 83 128 167 167 200 255 160 0 2 30 71 116 160 196 229 255 192 0 1 21 59 107 152 192 227 255 224 0 1 14 48 93 143 186 224 255 8 201013622 Next, compare the target cycle (step 2 ι β tooth light duty cycle and the previous frame backlight work cycle, and then drive the acceleration lookup table to get the drive acceleration back shape, J: medium M A picture illustrates the reaction wave of the backlight duty cycle signal, where N represents the target and DN-i/DN/D, which represents the d, ° box, N_1 represents the previous frame, and the backlight of the frame works. Intensity. If the previous message Dn.1<Dn), then the backlight of the current armature The cycle (that is, the drive plus back apricot τ ^, the expected intensity of the Dn D'N as the backlight of the front armature (step _, such as 'if the previous is 叱, 由于, because '32,, < _, while the eye (four) box of backlight work Zhou Xin
129 166 219 255 得到背光週期為，作為驅動:=動：迷查詢表查詢 由4動加送责先工作週期的輪出。 Π ’㈣轉加錢會形狀應_ 3() 反應時間遠快於未使用驅動加速之反應波形3^30’其 如果先前訊框的背光工作週期大於目前訊框的背光工 作週期（亦即，Dn-^Dn) ’則使用強度小於預期Dn Υ工 小強度D’N作為驅動加送背光工作週期的輪出（的較 22B)。如果先前訊框的背光工作週期等於或大約等於 9 201013622 訊框的彦光工作週期（亦即，Dn-fDn)，則使用強度等於 預期Dn的相同強度D’n作為驅動加送背光工作週期的輸出 (步驟22C)。 接著’將所產生的驅動加速背光工作週期訊號饋至背 光裝置（簡稱背光）或背光模組14，用以動態地控制背光 14的發光元件（例如冷陰極管、低速發光二極體或其他光 ©源）之開與關。該背光14因而提供照射光線至顯示面板 16 (步驟 23)。 根據本發明實施例’動態背光14的反應快於傳統未 使用驅動加速技術之背光。本發明提供大量製造背光裝置 的途控’此種動態背光不但能增快反應時間且不會犧牲成 本。 以上所述僅為本發明之較佳實施例 而已，並非用以限 定本發明之申請專利蘇阁. 、 圍，凡其它未脫離發明所揭示之精 神下所完成之等效改變武攸 雙4修飾，均應包含在下述之申請專 利範圍内。 【圖式簡單說明】 201013622 第一圖顯示本發明實施例之動態背光驅動加速 (overdrive)控制系統。 第二圖顯示本發明實施例之動態背光驅動加速控制方法的 流程步驟。 第三圖例示，背光工作週期訊號之反應波形。 【主要元件符號說明】 1 動態背光驅動加速（overdrive )控制系統 10 驅動加速裝置 12 緩衝器 14 背光 16 面板 2 動態背光驅動加速控制方法 20-23 動態背光驅動加速控制方法之步驟 30 使用驅動加速之反應波形 32 未使用驅動加速之反應波形 11129 166 219 255 Get the backlight cycle as, as the drive: = move: the fan query table query by the 4 move plus the responsibility of the first work cycle round. Π '(4) Transfer money will shape _ 3 () The reaction time is much faster than the response waveform of the unused drive acceleration 3^30'. If the backlight working period of the previous frame is greater than the backlight working period of the current frame (ie, Dn-^Dn) 'The intensity is less than the expected Dn. The small intensity D'N is used as the turn-off of the driving plus backlight duty cycle (compared to 22B). If the backlight duty cycle of the previous frame is equal to or approximately equal to the Yanguang duty cycle of the 201013622 frame (ie, Dn-fDn), the same intensity D'n with the intensity equal to the expected Dn is used as the driving plus backlight duty cycle. Output (step 22C). Then, the generated driving acceleration backlight duty cycle signal is fed to a backlight device (referred to as a backlight) or a backlight module 14 for dynamically controlling the light-emitting elements of the backlight 14 (for example, a cold cathode tube, a low-speed light-emitting diode, or other light). © source) on and off. The backlight 14 thus provides illumination to the display panel 16 (step 23). The dynamic backlight 14 reacts faster than conventional backlights that do not use drive acceleration techniques in accordance with embodiments of the present invention. The present invention provides a way to manufacture a large number of backlights. This dynamic backlight not only increases reaction time but also does not sacrifice cost. The above is only the preferred embodiment of the present invention, and is not intended to limit the invention of the present invention. The singularity of the singularity of the present invention is not limited to the spirit of the invention. , should be included in the scope of the patent application below. BRIEF DESCRIPTION OF THE DRAWINGS 201013622 The first figure shows a dynamic backlight drive overdrive control system in accordance with an embodiment of the present invention. The second figure shows the flow steps of the dynamic backlight driving acceleration control method of the embodiment of the present invention. The third figure illustrates the response waveform of the backlight duty cycle signal. [Main component symbol description] 1 Dynamic backlight drive overdrive control system 10 Drive acceleration device 12 Buffer 14 Backlight 16 Panel 2 Dynamic backlight drive acceleration control method 20-23 Step 30 of dynamic backlight drive acceleration control method Using drive acceleration Reaction waveform 32 does not use drive acceleration response waveform 11