TW200816121A - Liquid crystal display, circuit for adjusting light and method thereof - Google Patents

Abstract

A circuit for adjusting light and a method thereof are provided. The circuit and method of the present invention are adapted for the backlight module in the current liquid crystal display. The circuit changes the value of reference voltage and detection resistance to determine a reference current, and then determines the illumination of light unit in the backlight module according to the reference current. When the load current through light unit is greater than the reference current, variable impedance unit increases the loop impedance of light unit to decrease load current through light unit. On the other hand, when load current through light unit is smaller than the reference current, variable impedance unit decreases the loop impedance of light unit to increase load current through light unit. Thereby, it is possible to display the determined illumination by keeping the load current around the reference current.

Description

200816121 95103 19756twf.doc/t 九、發明說明： 【發明所屬之技術領域】 本發明是關於一種液晶顯示器之背光模組内多燈管亮 度調整的調光電路及方法，且特別是有關於一種可針對液 晶顯示器之背光模組内之燈管進行亮度調整的調光電路及 方法。 【先前技術】 近年來，由於液晶顯示面板（LCD panel)的尺寸越 做越大’故在液晶顯不面板之背光核組（例如為直下 式背光模組）所提供之面光源的燈管(例如:冷陰極管） 數目就會越多，而為了有效控制其製作成本及零件數 目，多燈管並聯（即相互平行排列而成）使用之技術便 應運而生。 然而，由於每一燈管本身的特性誤差大，以及每 一燈管與背光模組間的漏電流也因燈管排列方式及 背光模組之機板材質的不同而有差異，所以會造成流 經每一燈管的電流不同，而導致液晶顯示面板所呈現 的亮度不均（亦即某些區塊較暗或某些區塊較亮），故 控制其各燈管間的電流平衡便成為影響液晶顯示器 畫面品質好壞的關鍵。 圖1繪示為習知用以達到多燈管電流平衡的調 光電路之電路圖。請參照圖1，在調光電路之電路圖 100中包括多根燈管LrLs、多個高壓變壓器1>丁8、 多個電容C广C8，以及多個電流變壓器CTrCTy。其 中，高壓變壓器T〗〜T8會透過電容與燈管L〗〜L8 6 200816121 95103 19756twf.doc/t200816121 95103 19756twf.doc/t IX. Description of the Invention: [Technical Field] The present invention relates to a dimming circuit and method for adjusting brightness of a plurality of lamps in a backlight module of a liquid crystal display, and particularly relates to a A dimming circuit and method for adjusting brightness of a lamp tube in a backlight module of a liquid crystal display. [Prior Art] In recent years, since the size of the liquid crystal display panel (LCD panel) has become larger, the light source of the surface light source provided by the backlight core group of the liquid crystal display panel (for example, a direct type backlight module) For example, the number of cold cathode tubes will increase, and in order to effectively control the manufacturing cost and the number of parts, the technology of using multiple lamps in parallel (that is, arranged in parallel with each other) has emerged. However, since the characteristic error of each of the lamps themselves is large, and the leakage current between each of the lamps and the backlight module is also different due to the arrangement of the lamps and the material of the backlight module, the flow is caused. The current through each of the lamps is different, resulting in uneven brightness of the liquid crystal display panel (that is, some blocks are dark or some blocks are bright), so controlling the current balance between the lamps becomes The key to affecting the quality of LCD screens. 1 is a circuit diagram of a conventional dimming circuit for achieving multi-lamp current balance. Referring to Fig. 1, a circuit diagram 100 of a dimming circuit includes a plurality of lamps LrLs, a plurality of high voltage transformers 1>, a plurality of capacitors C, C8, and a plurality of current transformers CTrCTy. Among them, the high voltage transformer T 〖~T8 will pass through the capacitor and the lamp L 〗 〖L8 6 200816121 95103 19756twf.doc / t

連接，而電流變壓器CT〗〜CT7則配置在各燈管 間0 當高壓變歷 〜-人训伐队判反換-哭 (Inverter)所輸出的驅動訊號％後，會在高壓繳= T〗〜T8之二次侧產生驅動電流，且流經各燈管^°。 的驅動電流再利用電流變壓器CT1〜CT7來1〜L8 平衡，故每-燈管Ll〜L7戶斤發柄亮度“同到=Connection, and the current transformer CT〗 ~ CT7 is arranged between the lamps 0 When the high pressure catastrophe ~ - people training team to reverse the exchange - crying (Inverter) output drive signal %, will be in high pressure = T The secondary side of ~T8 generates a drive current and flows through each tube ^°. The driving current is again balanced by the current transformers CT1~CT7 to 1~L8, so the brightness of each lamp tube L1~L7 is "same to =

可以使得液晶顯示面板所呈現的亮度更均自。妙戶^ 習知所使用的電流變壓器CT]〜CT7因所佔面^， 且無法針對單一燈管進行調整，所以不但勢=士’ 高，且使用彈性空間不大。 、乍成本較 【發明内容】 有鑑於此，本發明的目的就是提供了一種 方法，其可針對液晶顯示器之背光模組内單—燈管7及 調整，故而可解決先前技術因採用電流變壓器二二 之缺點，所以可達到使用彈性空間較大、垆而二 小，以及製作成本低廉等優點。 豕面積 本發明的另-目的就是提供—種液晶顯示器，A藉由 將本發明之調光電路應用在其巾，除了可料到上述^ 明之調光電路的優點外，且可以使得液晶顯示面板所^ 現的免度更均勻，以達到提升液晶顯示器所呈現的晝 面品質。 基於上述及其他目的，本發明提供一種調光電路，其 適於控制液晶顯示器之背域組内發光單摘亮度，而此 調光電路包括_單元、比較單元，以及可㈣抗單元。 7 200816121 95103 19756twf.d〇c/t 其中，備測單元電性連接發光單元之第—端，用以债測流 經各^發光單元的^，並將其轉換_測電壓後輸出。 比較單TGf性連接偵爾元，用以將侧單元所輸出的偵 電壓與考電壓做比較，而輸出控制訊號。可變阻抗 f元電H連接比較單元與發光單元之第二端，此可變阻抗 單元依據比lx單元所輸$的控制訊號n變其阻值 一阻抗或第二組抗。 於本發明較佳實施例所述之調光電路，當偵測電壓大 =該參考電科，可變阻抗單元之阻值為第—阻抗， 1偵測電壓下降至參考電壓，而當躺電壓小於參考電壓 1，可k：阻抗％7〇之阻值為第二阻抗i以使得 升至參考電壓。 從另-觀點來看，本發明提供—種調光方法，盆適於 控制液晶顯示器之背光模組内發光單元的亮度，而此調光 括下列步驟··首先，設定—參考電流。接著，伯測 光單元的負載電流。其中，當負載電流大於參考電 增加發鮮元迴路之阻抗，以使負載電流下降至參、 一電流，反之，當負載電流小於參考電流時，降低發光 兀迴路之阻抗，喊負載電流上升至參考電流。 再從另一觀點來看，本發明提供一種液晶顯示哭，並 其中’背光模組係用以提 1、液曰曰顯不面板所需之光源’而此背光模組至少呈有 光單元與-調光電路。於本發明較佳實施 ς顯 示器，發光單元係用以產生光源，而調光電路則係 8 200816121 95103 19756twf.doc/t 制發光單70的亮度，且此調光電路包括控制單元與可變阻 抗單元。 於本务明較佳實施例所述之液晶顯示器，控制單元電 ϋ連接發光單元之第一端，用以偵測流經發光單元之電 流，並將其轉換成偵測電壓而與一參考電壓做比較， 出控制訊號。 ％The brightness exhibited by the liquid crystal display panel can be made more uniform. Miaohu ^ The current transformers CT]~CT7 used by the conventional technology cannot be adjusted for a single lamp because of the surface area, so the potential is not high, and the elastic space is not large. In view of the above, the object of the present invention is to provide a method for the single-light tube 7 and the adjustment of the backlight module of the liquid crystal display, so that the prior art can be solved by using the current transformer. The shortcomings of the second, so that the use of flexible space is large, the second and the second, and the production cost is low.豕 Area Another object of the present invention is to provide a liquid crystal display, A, by applying the dimming circuit of the present invention to its towel, in addition to the advantages of the above-described dimming circuit, The degree of uniformity is more uniform to improve the quality of the facet exhibited by the liquid crystal display. In view of the above and other objects, the present invention provides a dimming circuit adapted to control the brightness of a single illumination in a back-domain group of a liquid crystal display, and the dimming circuit includes a _ unit, a comparison unit, and a (four) anti-cell. 7 200816121 95103 19756twf.d〇c/t The test unit is electrically connected to the first end of the light-emitting unit, and is used to measure the flow through each of the light-emitting units, and convert it to a voltage measurement output. Comparing a single TGf connection detector element, the detection voltage outputted by the side unit is compared with the test voltage, and the control signal is output. The variable impedance f-element H is connected to the second end of the comparing unit and the light-emitting unit, and the variable-impedance unit changes its resistance by an impedance or a second set of reactance according to the control signal n input by the lx unit. In the dimming circuit according to the preferred embodiment of the present invention, when the detection voltage is large=the reference voltage, the resistance of the variable impedance unit is the first impedance, and the detection voltage drops to the reference voltage, and when the voltage is lying Less than the reference voltage 1, k: the resistance of the impedance %7〇 is the second impedance i such that it rises to the reference voltage. From another point of view, the present invention provides a dimming method for controlling the brightness of a light-emitting unit in a backlight module of a liquid crystal display, and the dimming includes the following steps: First, setting a reference current. Next, the load current of the light metering unit. Wherein, when the load current is greater than the reference electric power, the impedance of the fresh-bright circuit is increased, so that the load current drops to the reference and the current, and vice versa, when the load current is less than the reference current, the impedance of the illuminating 兀 circuit is lowered, and the load current rises to the reference. Current. From another point of view, the present invention provides a liquid crystal display crying, and wherein the 'backlight module is used to raise the liquid light required for the liquid crystal display panel, and the backlight module has at least a light unit and - Dimming circuit. In the preferred embodiment of the present invention, the display unit is configured to generate a light source, and the dimming circuit is a brightness of the light-emitting unit 70, and the dimming circuit includes a control unit and a variable impedance. unit. In the liquid crystal display of the preferred embodiment of the present invention, the control unit is electrically connected to the first end of the light emitting unit for detecting a current flowing through the light emitting unit and converting the detected current into a detecting voltage and a reference voltage. Compare and output control signals. %

於本發明較佳實施例所述之液晶顯示器，控制單元包 括價，單福味單元。其巾，制料紐連接發光^ 兀之第一端，用以偵測流經發光單元的電流，並將其轉換 成偵^1電壓後輸出。比較單元電性連接侧單it，用以將 偵測單元所輸出的偵測電壓與-參考電壓做比較，而輸出 一於本發明較佳實施例所述之液晶顯示器，可變阻抗 兀電性連接比較單元與發光單元H，此可變阻抗單 70依據比較單元所輸出的控制訊號，而改變其阻值為第一 阻抗或第二組抗。 Μ 於本發明較佳實施例所述之液晶顯示器，當備測電壓 大於翏考電可變阻抗單元之阻值為第—阻抗， 得偵測電壓下降至參考電壓貞測 :至二阻抗，得偵測= ρ ί的調光電路及其方法，可以應用於現今 模組中，其藉由改變可變阻抗單元之阻 抗，而增加或降低背光模組内發光單元的迴路阻抗， 200816121 95103 l9756twf.doc/t =變流經發光單元之電流為設計者先前所設定的表In the liquid crystal display of the preferred embodiment of the present invention, the control unit includes a valence, single-blessness unit. The towel, the material button is connected to the first end of the light emitting device, for detecting the current flowing through the light emitting unit, and converting it into a voltage of the detector and outputting it. The comparison unit is electrically connected to the side unit to compare the detection voltage outputted by the detection unit with the reference voltage, and outputs a liquid crystal display according to the preferred embodiment of the present invention. The comparison unit and the illumination unit H are connected, and the variable impedance unit 70 changes its resistance to the first impedance or the second group according to the control signal output by the comparison unit. In the liquid crystal display according to the preferred embodiment of the present invention, when the measured voltage is greater than the resistance of the variable impedance unit, the detected voltage drops to the reference voltage: to the second impedance. The dimming circuit and method thereof for detecting = ρ ί can be applied to the current module, which increases or decreases the loop impedance of the light-emitting unit in the backlight module by changing the impedance of the variable impedance unit, 200816121 95103 l9756twf. Doc/t = current through the illuminating unit is the table previously set by the designer

=針對背光餘内任-發光單元進行亮度罐，^直到 =無性空間較大、佔據面積小，以及製作成本 ^點。除此之外，正因本發明之液晶顯示器係因庫用本 發明之調光電路於其背光模財，故林可以達到I列戶^ 述之優點外1可以使得液晶顯示面板所呈現 ^ 均句，以達到提升液晶顯示器所呈現的晝面品質，更 為讓本發明之上述和其他目的、特徵和優點能更明 憧，下文特舉本㈣讀彳4實蘭，魏合所 羊 說明如下。 卜评細 【實施方式】 圖士繪示為賴树明較佳實施例之調光電路的 圖。請茶照圖2 ’調光電路2〇〇係例如可以用以控制液曰 顯不器（未緣示)之背光模組(backlight module)内發光單$ L!(例如.燈管、冷陰極管、螢光燈、齒素燈…等)之亮产， 但在此亚不限财應祕本發明之技觸域。也就是說， 只要有需要發光單元Li之亮度時，其雖非應用於本發 明之技術領Ά惟其㈣於本發明之保護範圍。 調光電路200包括控制單元2〇1與可變阻抗單元 203其中’控制單元2〇1是用來摘測流經發光單元之 電流iL’並將其轉換為_電壓（亦即為電流L乘上侧電 阻RD之阻值卜與„參考電壓Vr』比較後輸出控制訊 號CS。於本實施例中’控制單元2〇1包括侧單元篇 200816121 95103 I9756twf.doc/t 與比，單元2〇1b。其中，偵測單元2〇la是用以债測流經 發光單TO L〗之電流iL，並將其轉換為偵測電壓，而比較單 元201b則是用以將偵測電壓與參考電壓Vref做比較，而輸 出控制訊號CS。 本實施例之偵測單元201a係由第一二極體Di、第二 , 二極體D2,以及偵測電阻RD所組成。其中，二極體^ 之陽極與侧電阻^之第二端用以接收—參考電位(例如 • 為f地電位，但不限制於此電位），二極體D1之陰極與發 光單元第一端及二極體〇2之陽極彼此電性連接，而二極體 D2之陰極則電性連接偵測電阻Rd之第一端。 、此外，比較單元201b係由比較器〇P、回授電容cf， 以及回授電阻Rf所組成。其中，比較器〇p之正輪入端 ^以接收參考電壓H比較器〇P之負輪人端㈠電性 L接偵測電阻rd之第一端及回授電阻Rf之第一端。回授 Rf之，二端電性連接回授電容Cf之第—端，而回授 φ “合Cf之第二端則電性連接比較器OP之輸出端。 . —清繼續參照圖2，可變阻抗單元203電性連接發光單= For the backlight, the internal light-emitting unit is used for the brightness tank, ^ until = the non-sex space is large, the occupied area is small, and the manufacturing cost is ^. In addition, because the liquid crystal display of the present invention uses the dimming circuit of the present invention in the backlight mode of the library, the forest can achieve the advantages described in the first column, and the liquid crystal display panel can be rendered. The above and other objects, features and advantages of the present invention will be more apparent in order to improve the quality of the facet exhibited by the liquid crystal display. The following is a special description of this (4) reading 实 4 Shilan, Wei He's sheep explained below . BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment] The figure is shown as a dimming circuit of the preferred embodiment of Lai Shuming. Please refer to Figure 2 'The dimming circuit 2' for example, which can be used to control the backlight module in the backlight module (not shown) (for example, lamp, cold cathode) Tubes, fluorescent lamps, dentate lamps, etc.), but in this Asia, it is not limited to the technical touch of the invention. That is to say, as long as the brightness of the light-emitting unit Li is required, it is not applicable to the technical scope of the present invention, and it is (4) within the protection scope of the present invention. The dimming circuit 200 includes a control unit 〇1 and a variable impedance unit 203, wherein the 'control unit 〇1 is used to extract the current iL' flowing through the illuminating unit and convert it into a _ voltage (that is, a current L multiplied The resistance value of the upper resistor RD is compared with the reference voltage Vr, and the control signal CS is output. In the present embodiment, the control unit 2〇1 includes the side unit 200816121 95103 I9756twf.doc/t and the ratio, the unit 2〇1b The detecting unit 2〇1a is used for measuring the current iL flowing through the light emitting unit TO L and converting it into a detecting voltage, and the comparing unit 201b is for detecting the voltage and the reference voltage Vref. For comparison, the control unit CS is output. The detecting unit 201a of the embodiment is composed of a first diode Di, a second diode, a diode D2, and a detecting resistor RD. The second end of the side resistor is used to receive a reference potential (eg, f ground potential, but not limited to this potential), the cathode of the diode D1 and the first end of the light emitting unit and the anode of the diode 〇2 Electrically connected to each other, and the cathode of the diode D2 is electrically connected to the first of the detecting resistor Rd In addition, the comparing unit 201b is composed of a comparator 〇P, a feedback capacitor cf, and a feedback resistor Rf, wherein the positive input terminal of the comparator 〇p receives the reference voltage H and the comparator 〇P is negative. The first end of the wheel (1) is connected to the first end of the detecting resistor rd and the first end of the feedback resistor Rf. The Rf is fed back, and the two ends are electrically connected to the first end of the capacitor Cf, and the feedback φ The second end of the Cf is electrically connected to the output end of the comparator OP. - Clearly referring to FIG. 2, the variable impedance unit 203 is electrically connected to the light emitting unit.

Ll與控制單元201，用以接收由反換流器(Invert杜，未 =不)所輸出之驅動訊號ν〇，並透過第一電容c將驅動訊 L d傳送至發光單元l與控制單元，且依據控制單 广201。所輪出的控制訊號cs，而決定增加或降低發光單元 第I之迴路阻抗，以控制偵測電壓處在參考電壓乂其中， 弟電各c係用以濾除驅動訊號Vd的直流成份。 於本貫施例中，當偵測電壓大於參考電壓vref時，可 200816121 95103 19756twf.doc/t 變阻抗單元203之阻值為第一阻抗，而增加 =單:=電=_壓\，二 vrefB, , ^ 降牴癸杏罝；τ 、 平兀 之丨且值為弟二阻抗，而 ^ 1之迴路阻抗，以使得偵測電壓上升至 電壓Y而調整流經發光單灿之電流^升至參考 Α 例之可冑阻抗單元期係由開關SW(例如可以 為，電晶體或任何具有開關功能之元件）、第一2 、弟一電阻R2，以及高壓變壓器所級成。i中， 連接比較器0p之輸出端，而開關s; 之弟各別電性連接第—電阻&一一 =二電阻"1之第-娜連接開關，之第二端： =1且R2之弟一端則電性連接高壓變壓器 。高嶋，Tl之二次侧的第二端電性連接第人： in之1 一端，而高壓變壓器乃之一次側則用以接收 反換抓态所輪出之驅動訊號％ 〇 而為了更清楚地說明上述實施例的内容，以下再 個祀例.請灣參照圖2，若要決定發光單元^所呈現之 亮度的大/J、’可藉由改變比較器〇p之正輸入端(+)所接收 的^考電麗Vref之值與偵測電阻Rd之阻值，而決定流經發 光早兀L】之電流iL，亦即將參考· I之數值除以^ 電阻rd之阻值可得知。 、 因此’當南屢變麼器T〗之-次側接收到反換流器所輪 出的正半週驅動訊號VD後，由於發光單元^可等效看做 12 200816121 95103 19756twf. doc/t 一電阻&，且此時二極體认會 流經發光單元L】之電流iL，即正半週H疋理^出 ==τΤΐ:其中發先單元Li之鱗阻抗包含; 向二側阻抗、等效電阻、二極料順 ¥通^几r〇,以及偵測電阻RD之阻值。 設定in了要使得流經發料元1"之電U先前所 口又疋麥考·電壓V之值盥 ㈣尸厂 入 值。故依攄上、阻值所求得之 徉到伯、目丨ΐ厂求件的電流iL流經侧電阻後，會 :到、偵測严且此偵測電物至比較器0P之負輸 ref 做比較 =b=°I之f輪入端(+)所接收的參考電壓兄 ^ 雨.一控制訊號CS至開關SW的控制端。 所輪出之電壓大於參考電壓Vref時，比較器op ^工制訊號CS會致使開W SW截止，故高壓變壓 _ ΐί^Γ次侧阻抗會提升(即為第—電叫之阻值累加第 有^ 2之阻值）’而眾所皆知地，由於高壓變壓器Τ!呈 數=且=壓=依據高壓變壓器Τ|一次側£ ^ τ 。欠反。0 T1之二次側阻抗提升會引起高壓變壓 i路1二―次#純亦提升，0此便增加了發光單元一之 二會降低流經發光單仏m，故债測 冤壓亦下降至參考電壓V时。 所乂之，當侧電壓小於參考電壓m比較器⑽ 之控制訊號cs會致使開M sw導通，故高壓變壓 次側阻抗會下降(即為第—電阻R1之阻值），所以 、回壓變壓器ΤΆ—、二次側隨關係，高壓變壓器 13 200816121 95103 19756twf.doc/tThe L1 and the control unit 201 are configured to receive the driving signal ν〇 outputted by the inverter (Invert Du, No=No), and transmit the driving signal L d to the lighting unit 1 and the control unit through the first capacitor c. And according to the control list 201. The control signal cs is turned on, and it is decided to increase or decrease the impedance of the first circuit of the light-emitting unit to control the detection voltage to be in the reference voltage, and the c-series are used to filter the DC component of the driving signal Vd. In the present embodiment, when the detection voltage is greater than the reference voltage vref, the resistance of the 200816121 95103 19756 twf.doc/t variable impedance unit 203 is the first impedance, and the increase = single: = electricity = _ pressure \, two vrefB, , ^ 牴癸 牴癸 牴癸 罝; τ 、 兀 丨 丨 丨 丨 丨 丨 τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ The 胄 胄 impedance unit period to the reference 级 example is composed of a switch SW (for example, a transistor or any component having a switching function), a first 2, a resistor R2, and a high voltage transformer. i, the output of the comparator 0p is connected, and the switch s; the brothers are electrically connected to the first-resistance & one = two resistance " 1 of the first-to-nap switch, the second end: =1 and One end of the R2 is electrically connected to the high voltage transformer. The sorghum, the second end of the secondary side of Tl is electrically connected to the first person: the one end of the in 1 and the primary side of the high voltage transformer is used to receive the driving signal % 轮 rotated by the reverse switching state, and more clearly Explain the content of the above embodiment, the following example. Please refer to Figure 2, to determine the brightness of the light-emitting unit ^ / /, can be changed by changing the positive input (+) of the comparator 〇p The value of the received voltage Vref and the resistance of the detecting resistor Rd determine the current iL flowing through the light illuminating L], and the value of the reference I is divided by the resistance of the resistor rd. . Therefore, after the positive half-cycle drive signal VD that the reverse converter has rotated, the secondary unit can be equivalently regarded as 12 200816121 95103 19756twf. doc/t a resistor & and at this time the diode recognizes the current iL flowing through the light-emitting unit L], that is, the positive half-cycle H疋^^==τΤΐ: where the scale element of the first-order unit Li is included; , the equivalent resistance, the two-pole material 顺¥通^ several r〇, and the resistance RD resistance. Set in in order to make the flow of the material 1 " the previous U and the value of the voltage V (盥) corps into the value. Therefore, according to the upper and lower values obtained by the resistance, the current iL flowing through the device and the target device will flow through the side resistor, and will: detect and detect the negative to the comparator 0P. Ref Compare =b=°I f The input voltage received by the wheel (+) is the control voltage of the control signal CS to the switch SW. When the voltage of the turn-out is greater than the reference voltage Vref, the comparator op ^ working signal CS will cause the open W SW to be cut off, so the high-voltage transformer _ ΐ ί Γ Γ 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗 阻抗The first has a resistance value of ^ 2)' and it is well known that due to the high voltage transformer 呈! number = and = pressure = according to the high voltage transformer Τ | primary side £ ^ τ. Inverse. 0 T1's secondary side impedance increase will cause high pressure to change pressure i road 1 2 - times # pure also improve, 0 will increase the light-emitting unit one of the two will reduce the flow through the light single 仏 m, so the debt test pressure is also reduced When the reference voltage V is reached. Therefore, when the side voltage is less than the reference voltage m, the control signal cs of the comparator (10) will cause the opening M sw to be turned on, so the impedance of the secondary side of the high voltage transformer will drop (that is, the resistance of the first resistor R1), so back pressure Transformer ΤΆ—, secondary side relationship, high voltage transformer 13 200816121 95103 19756twf.doc/t

Tl之二次侧阻抗下降會引起高壓變壓器Ti之 亦下降，便降低了^光單灿之迴路阻 : 加流經發光單元L〗之電流iL，故偵測電壓 二^ 壓Vref。在本實施例中，高壓變壓器τ ^升 > 考電 幅度’可藉由調整第-電阻Rl與第二電阻=;=文= 是高壓變壓器1之一、二次側匝數。 ^The lowering of the impedance of the secondary side of Tl causes the high voltage transformer Ti to also drop, which reduces the loop resistance of the light single light: plus the current iL flowing through the light emitting unit L, so the detection voltage is equal to Vref. In the present embodiment, the high voltage transformer τ ^ liter > the test amplitude ' can be adjusted by adjusting the first-resistance R1 and the second resistance =; = text = is one of the high-voltage transformer 1, the secondary side turns. ^

# 由於比較器會反覆地比較偵測電屬與 Vref’故藉由如此反覆的動作嗜得偵測電壓會維 電壓Vref，所以流經發光單元L1之電流iL會維持 2 設定參考電壓Vw之值與_電阻RD之阻值 』斤 值。而值得一提的是’為了要使得比較器op處於正石I 工作區（即讓比較If QP運作在比較之動作），在本實施例 中，在比較器OP之負回授迴路上加入回授電容^盘 電阻Rf，以抑制比較器0P運作在非正確的工作區（例如^ 4)。 辰 另外，圖2所揭露的調光電路2〇〇是針對反換流界 輸出的正半週驅動訊號vD動作，但熟悉此技藝者當可:， 當高壓變壓If H次侧接收到反換流器所輪出 遇驅動訊號VD時，亦可依據本發明之精神，以控制流細 發光單兀L]之電流iL會維持在先前所設定參考電壓乂工 之數值與偵測電阻RD之阻值所求得之值。 "ef 圖3繪示為運用本發明調光電路以達到多個發光單 元電流平衡之電路圖。請參照圖3，由圖3所揭露= 多個發光單元電流平衡之電路圖中包括多個調光電 14 200816121 95103 19756twf.doc/t 路200a〜200η與多個發光單元L]〜Ln。其中，調光電 路200a〜200η之功效與耦接關係與圖2所揭露的調光 電路200類似，故在此並不再加以贅述之，而 達到發光單元Ι^η的電流平衡，只需將參考電屢 Vref]〜Vrefn ^數值與偵測電阻RDi〜RDn之阻值皆設為 一致，發光單元1^〜1^所呈現的亮度就會相同，以 到發光單元L]〜Ln的電流平衡，如此液晶顯示面板所 =現的贵度會更均勻，而其所應用的液晶顯示器之書面品 質亦會隨之提升。 一曲 承接上述，圖3所揭露的多個發光單元l l ^衡之電路圖中的發光單元[A，可並 η ^于排列而成）制，而運用在液晶顯示面板 Ϊ =外，使用者可依據實際設計需求，而適時的 受動茶考電壓Vrefl〜Vrefn之數值與偵 之阻值，來達成其它設計之功效。 D1 R〇n 山為了要達到上述調光電路所能提供的功效，以 出一種調光方法。圖4繪示為依昭本發 A牛 ::光方法的流程圖。請參照圖發 * 發，單元(例如:燈管、冷陰極管、瑩光燈、 老帝、、“ 中5又疋—參考電流。其中，此泉 發光單元;=經發光單元之電流/亦是決定 接著，在步驟S403中，偵測流經發光單元的負 15 200816121 95103 19756twf.doc/t 載電流，並如步驟S4〇5所述，當負載電流大於參考 電流日^，增加發光單元迴路之阻抗，以使負載電流下 降至參考電流，反之，當負載電流小於參考電流時， 降低發光單元迴路之阻抗，以使負載電流上升至參考 電流，藉此控制負载電流值接近參考電流值，以呈現 先前所決定之發光單元的亮度。 綜上所述，本發明提供了 一種調光電路及方法，其可 • 應、用於現今液晶顯示器之背光模組中。而依據上述的實施 例，本發明至少包含下列優點·· ^ 1 ·利用可Μ阻抗單元取代先前技術所使用的電流變壓 器，以節省佔據面積；故可降低製作成本。 2.可針對液晶顯示器之背光模組内單一發光單元進行 調整，故使用彈性空間較大。 ‘ 3·藉由將本發明之調光電路應用於液晶顯示器之背光 模組中，故可以使得液晶顯示面板所呈現的亮度更均勻， φ 以達到提升液晶顯示器所呈現的晝面品質。 雖然本發明已以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 和範圍内，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為準。 【圖式簡單說明】 圖1繪示為習知用以達到多燈管電流平衡的 光電路之電路圖。 σ 圖2繪示為依照本發明較佳實施例之調光電路的帝 圖。 包峪 16 200816121 95103 19756twf.doc/t 圖3繪示為運用本發明調光電路以達到多燈 衡之電路圖。 圖4繪示為依照本發明較佳實施例之調光方法的流程圖。 【主要元件符號說明】 100、200、200a〜200η :調光電路 201 :控制單元 201a :偵測單元 201b :比較單元 203:可變阻抗單元 L!〜Ln :燈管 Τι〜τ8 :高壓變壓器 C :第一電容 c!〜c8 :電容 CTVCT7 :電流變壓器 D!:第一二極體 D2 :第二二極體# Since the comparator will repeatedly compare the detected electric current with Vref', so as to detect the voltage Vever voltage Vref by such repeated action, the current iL flowing through the light-emitting unit L1 will maintain the value of the 2 set reference voltage Vw. And the resistance value of _ resistance RD. It is worth mentioning that 'in order to make the comparator op in the Orthogonal I working area (that is, let the comparison If QP operate in comparison), in this embodiment, add back to the negative feedback loop of the comparator OP. The capacitor ^R resistor Rf is applied to suppress the comparator 0P from operating in an incorrect working area (eg ^ 4). In addition, the dimming circuit 2〇〇 disclosed in FIG. 2 is a positive half-cycle driving signal vD action for the reverse commutation output, but those skilled in the art can: when the high-voltage transformer If H sub-side receives the counter When the inverter receives the driving signal VD, according to the spirit of the present invention, the current iL of the control flow light emitting unit L] is maintained at the value of the previously set reference voltage and the detecting resistance RD. The value obtained by the resistance value. "ef Figure 3 is a circuit diagram showing the current balancing of a plurality of light-emitting units using the dimming circuit of the present invention. Referring to FIG. 3, the circuit diagram of the current balancing of the plurality of light-emitting units is disclosed in FIG. 3, and includes a plurality of light-modulating signals 14200816121 95103 19756twf.doc/t paths 200a-200n and a plurality of light-emitting units L]~Ln. The functions and coupling relationships of the dimming circuits 200a to 200n are similar to those of the dimming circuit 200 disclosed in FIG. 2, and thus are not described herein again, and the current balance of the light-emitting unit is achieved, and only The reference voltage Vref]~Vrefn^ value and the detection resistances RDi~RDn are all set to be the same, and the brightness of the light-emitting units 1^~1^ is the same, so that the current balance of the light-emitting units L]~Ln Therefore, the current value of the liquid crystal display panel will be more uniform, and the written quality of the liquid crystal display to which it is applied will also increase. According to the above, the plurality of light-emitting units of the plurality of light-emitting units disclosed in FIG. 3 are formed by the light-emitting units [A, which can be arranged in an array], and are used in the liquid crystal display panel Ϊ = According to the actual design requirements, and timely, the value of the tea test voltage Vrefl ~ Vrefn and the resistance value of the detection to achieve other design effects. D1 R〇n Mountain has a dimming method in order to achieve the efficacy of the above dimming circuit. FIG. 4 is a flow chart showing the method of A-Beef: Light in accordance with the present invention. Please refer to the figure for sending hair, unit (for example: lamp, cold cathode tube, fluorescent lamp, old emperor, "middle 5 and 疋 - reference current. Among them, this spring light unit; = current through the light unit / It is determined that, in step S403, a negative current of 200816121 95103 19756twf.doc/t current flowing through the light-emitting unit is detected, and as described in step S4〇5, when the load current is greater than the reference current day, the light-emitting unit circuit is increased. The impedance is such that the load current drops to the reference current. Conversely, when the load current is less than the reference current, the impedance of the light-emitting unit circuit is lowered to cause the load current to rise to the reference current, thereby controlling the load current value to be close to the reference current value, Presenting the brightness of the previously determined illumination unit. In summary, the present invention provides a dimming circuit and method that can be used in a backlight module of a current liquid crystal display. According to the above embodiment, The invention at least includes the following advantages: · 1 · Replacing the current transformer used in the prior art with a Μ-impedance unit to save the occupied area; therefore, the manufacturing cost can be reduced. It can be adjusted for a single light-emitting unit in the backlight module of the liquid crystal display, so the use of the flexible space is large. '3. By applying the dimming circuit of the present invention to the backlight module of the liquid crystal display, the liquid crystal display can be made The brightness of the panel is more uniform, φ to improve the quality of the facet exhibited by the liquid crystal display. Although the invention has been disclosed in the preferred embodiments as above, it is not intended to limit the invention, and anyone skilled in the art; The scope of protection of the present invention is defined by the scope of the appended claims, and the scope of the invention is defined by the scope of the appended claims. A circuit diagram of an optical circuit for achieving multi-lamp current balance is shown. σ Figure 2 is a diagram of a dimming circuit in accordance with a preferred embodiment of the present invention. 包 峪 16 200816121 95103 19756 twf.doc/t Figure 3 FIG. 4 is a flow chart showing a dimming method according to a preferred embodiment of the present invention. FIG. 4 is a flow chart showing a dimming method according to a preferred embodiment of the present invention. 100, 200, 200a to 200n: dimming circuit 201: control unit 201a: detecting unit 201b: comparing unit 203: variable impedance unit L!~Ln: lamp Τι~τ8: high voltage transformer C: first capacitor c !~c8: Capacitor CTVCT7: Current Transformer D!: First Diode D2: Second Diode

Rd ·彳貞測電阻 OP :比較器 cf:回授電容Rd · Measure resistance OP : Comparator cf: feedback capacitor

Rf:回授電阻 SW :開關Rf: feedback resistor SW: switch

Ri :第一電阻 R2 :第二電阻 S40ί〜S405 :本發明較佳實施例所繪示之調光方法流 程圖的各步驟 17Ri: first resistor R2: second resistor S40ί~S405: steps of the flow chart of the dimming method shown in the preferred embodiment of the present invention 17

Claims (1)

200816121 95103 19756twf.doc/t 十、申請專利範圍： 1.-種調減路，適於控制—液晶顯示器之一背 組内-發光單元之亮度，而該調光電路包括： 、 -偵測單S，電性連接該發光單元之第—端，用以债 f流經該發光單元之電流，並將其轉換成—制電壓後輸 出，200816121 95103 19756twf.doc/t X. Patent application scope: 1.- Kind of adjustment and deduction, suitable for control - brightness of one of the liquid crystal display in the back group - the light-emitting unit, and the dimming circuit comprises: S, electrically connecting the first end of the light-emitting unit, for the current flowing through the light-emitting unit of the debt f, and converting the current into a voltage, and outputting m y比較單元，電性連接_測衫，用以比較該偵測 電廢與-茶考電壓，而輸出—控制訊號；以及 斤-可變阻抗單元，電性連接該比較單元與該發光單元 之第二端，依據該控制訊號而改變其阻值為一第一阻抗 一弟二阻抗， 其中，當該偵測電壓大於該參考電壓時，該可變阻抗 單元之阻值為該第一阻抗，以使得該偵測電壓下降至該參 f電壓，而當該偵測電壓小於該參考電壓時，該可變阻抗 單元之阻值為該第二阻抗，以使得該偵測電壓上升至該泉 考電壓。 口乂多 2·如申請專利範圍第1項所述之調光電路，1中哕 測單元包括：八^ 、 一第一二極體，其陰極電性連接該發光單元之第一 端，而該第一二極體之陽極電性連接第一參考電位； 一第二二極體，其陽極電性連接該發光單元之第一 端；以及 一偵測電阻，其第一端電性連接該第二二極體之陰 極’而該偵測電阻之第二端電性連接第二參考電位。 3·如申請專利範圍第1項所述之調光電路，其中該比 18 200816121 95103 19756twf.doc/t 車二元包括-比較器’其二輪入端用以分別接收該參考電 屋契錄則電壓，而該比較器之輸出端則輸出該控制訊號。 4. 如申請專利範圍第3項所述之調光電路，其中該比 較單元更包括·· -回授電阻’其第-端電性連接該比較器之二輸入端 其中之一；以及 山一回授電容，其第-端電性連接該回授電阻之第二 ‘而=授電容之第二端則電性連接該比較器之輸出端。 5. 如申請專利範圍第η所述 中 變阻抗單元包括： ' ^ ^ J 開關，其控制端用以接收該控制訊號； 一第一電阻，與該開關並聯； 一第二電阻，與該開關串聯； 止狀ί中’當該偵測電壓大於該參考電壓時，該開關為截 4二3得該可變阻抗單元之阻值為該第-阻抗，而 小於該參考電壓時，該開關為導通狀態，以 使传5亥可變阻抗單元之阻值為該第二阻抗。 申請專利範圍第5項所述之調光電路，其中該可 換流器所輪出二:剩壓器之-次侧則接收反 光電路專利範圍第5項所述之調光電路，其中該調 電.~壓_之 士申明專利felij第1項所述之調光電路，其中該發 19 200816121 95103 19756twf.doc/t 光單元包括燈管、冷陰極管、螢光燈或齒素燈。 9·-種調:¾方法，適於控制—液晶顯示器之—背 組内7發光單元之紐，而該調光方法包括下列步驟果 設定一參考電流； 偵測流經該發光單元之一負載電流； 當該負載電流大於該參考電流時，增加該發光單 之阻抗’以使該負载電流下降至該參考電流；以及 *該負載電流小於該參考電流時，降低該發 路之阻抗，以使該負載電流上升至該參考電流。 噁 10=請專·圍第9項所述之調光方法，其中 先早几包括燈管、冷陰極管、螢光燈或㈣燈。 ^ 1·一種液晶顯示器，包括： 一液晶顯示面板，以及 调二ίί模組’其係用以提供該液晶顯示面板所需之并 源，而該背光模組至少包括： 《而〈先 m 一發光單元，其係用以產生光源；以及 調光電路’其係用以控制該發光單元之 測’電性連接該發光單元之第-端，用以伯 -：ϊϊϋ70之電流’並將其轉換成-偵測電壓而與 参考電堡做比較，以輸出一控制訊號；以及 、 之第3變=單元’電性連接該控制單元與該發光單元 一疒二依據該控制訊號而改變其阻抗為一第一阻抗 壓時，該可變阻抗 其中；當該偵測電壓大於該參考電 20 200816121 95103 19756twf.doc/t 早元之阻抗為該第一阻抗，以使得該彳貞測電壓下降至該參 考電壓，而當該偵測電壓小於該參考電壓時，該可變阻抗 單元之阻抗為該第二阻抗，以使得該偵測電壓上升至該參 考電壓。 12·如申請專利範圍第11項所述之液晶顯示器，其中 該控制單元包括： • 一偵測單元，電性連接該發光單元之第一端，用以偵 • 測流經該發光單元之電流，並將其轉換成一偵测電壓後輸 着出；以及 一比較單元，電性連接該偵測單元，用以比較該偵測 電壓與一參考電壓，而輸出一控制訊號。 13. 如申請專利範圍第12項所述之液晶顯示器，其中 該偵測單元包括： 一第一二極體，其陰極電性連接該發光單元之第一 端，而該第一二極體之陽極電性連接第一參考電位； 一第二二極體，其陽極電性連接該發光單元之第一 φ 端；以及 • 一偵測電陳，其第一端電性連接該第二二極體之陰 _ 極，而該偵測電阻之第二端電性連接第二參考電位。 14. 如申請專利範圍第12項所述之液晶顯示器，其中 該比較單元包括一比較器，其二輸入端分別用以接收該參 考電壓與該偵測電壓，而該比較器之輸出端則輸出該控制 訊號。 15. 如申請專利範圍第14項所述之液晶顯示器，其中 該比較單元更包括： 21 200816121 95103 19756twf.doc/t 其中之一；以及、、第一端電性連接該比較器之二輪入端 一回授電容，发昝 端，而該回授電容：；—=生連接該回授電阻之第二 16如申嗜容刹μ弗一知則耦接該比較器之輪出端。 該可變；項料__，其中 一 f關·其控制端用以接收該控制訊號，· 2一電阻’與該開關並聯； 一第二電阻，與該開關串聯； 止狀ί中以忿該=壓時，該開關為截 於該參考電壓:，該二'ί::: 使付该可變阻抗單元之阻抗為該第二阻抗。心 又丨仇平7〇更包括一高壓蠻靨哭， Φ 該第一電阻與該第二電阻，而該高i變壓芯侧， 收反換流器所輪出之驅動訊號。^之—次側則接 該調1 光範圍第16項所述之液晶顯示器，其中 器之-次側元連接於該高壓變壓 該發光單元包圍！二，S液晶顯示器，其中 u拓& &、冷陰極官、螢光燈或鹵素燈。 22a comparison unit, an electrical connection _ trouser for comparing the detected electrical waste and the tea test voltage, and an output-control signal; and a jin-variable impedance unit electrically connected to the comparison unit and the illuminating unit The second end changes the resistance to a first impedance and a second impedance according to the control signal. When the detection voltage is greater than the reference voltage, the resistance of the variable impedance unit is the first impedance. So that the detection voltage is lowered to the voltage of the reference f, and when the detection voltage is less than the reference voltage, the resistance of the variable impedance unit is the second impedance, so that the detection voltage rises to the spring Voltage. 2. The dimming circuit according to the first aspect of the patent application, wherein the detecting unit comprises: a first diode, the cathode is electrically connected to the first end of the light emitting unit, and The anode of the first diode is electrically connected to the first reference potential; the second diode has an anode electrically connected to the first end of the light emitting unit; and a detecting resistor, the first end of which is electrically connected to the first terminal The cathode of the second diode is 'the second end of the detecting resistor is electrically connected to the second reference potential. 3. The dimming circuit as claimed in claim 1, wherein the ratio 18 200816121 95103 19756 twf.doc/t vehicle binary includes a comparator - the second wheel is used to receive the reference electric house Voltage, and the output of the comparator outputs the control signal. 4. The dimming circuit of claim 3, wherein the comparing unit further comprises: - a feedback resistor 'the first end of which is electrically connected to one of the input terminals of the comparator; and The capacitor is electrically coupled to the second end of the feedback resistor and the second end of the capacitor is electrically connected to the output of the comparator. 5. The medium-impedance impedance unit as described in claim η includes: a ^ ^ J switch whose control terminal is used to receive the control signal; a first resistor connected in parallel with the switch; a second resistor, and the switch When the detection voltage is greater than the reference voltage, the switch is cut off 4:3, the resistance of the variable impedance unit is the first impedance, and when the voltage is less than the reference voltage, the switch is The conduction state is such that the resistance of the 5 hm variable impedance unit is the second impedance. The dimming circuit of claim 5, wherein the converter is rotated 2: the secondary side of the residual pressure device receives the dimming circuit described in the fifth aspect of the reflective circuit, wherein the adjustment The light dimming circuit described in the patent item felij, wherein the light source unit comprises a lamp tube, a cold cathode tube, a fluorescent lamp or a dentate lamp. 9·- species adjustment: 3⁄4 method, suitable for control—liquid crystal display—the 7-light unit of the back group, and the dimming method includes the following steps: setting a reference current; detecting a load flowing through one of the illumination units a current; when the load current is greater than the reference current, increasing an impedance of the illuminating unit to decrease the load current to the reference current; and * when the load current is less than the reference current, reducing an impedance of the transmitting circuit to enable The load current rises to the reference current. Evil 10=Please refer to the dimming method described in item 9, which includes a lamp, a cold cathode tube, a fluorescent lamp or a (four) lamp. ^1· A liquid crystal display comprising: a liquid crystal display panel, and a two-dimensional module for providing a parallel source required for the liquid crystal display panel, and the backlight module comprises at least: a light-emitting unit for generating a light source; and a dimming circuit for controlling the light-emitting unit to electrically connect to the first end of the light-emitting unit, and to convert and convert the current of the light-emitting unit 70 The detection-voltage is compared with the reference electric castle to output a control signal; and the third change=unit is electrically connected to the control unit and the illumination unit to change its impedance according to the control signal. a first impedance, wherein the detected voltage is greater than the reference voltage 20 200816121 95103 19756 twf.doc / t early element impedance is the first impedance, such that the measured voltage drops to the a reference voltage, and when the detection voltage is less than the reference voltage, the impedance of the variable impedance unit is the second impedance, so that the detection voltage rises to the reference voltage. The liquid crystal display of claim 11, wherein the control unit comprises: • a detecting unit electrically connected to the first end of the light emitting unit for detecting a current flowing through the light emitting unit And converting it into a detection voltage and outputting; and a comparison unit electrically connected to the detection unit for comparing the detection voltage with a reference voltage and outputting a control signal. 13. The liquid crystal display of claim 12, wherein the detecting unit comprises: a first diode, the cathode of which is electrically connected to the first end of the light emitting unit, and the first diode The anode is electrically connected to the first reference potential; the second diode has an anode electrically connected to the first φ end of the light emitting unit; and • a detecting electrode, the first end of which is electrically connected to the second diode The cathode of the body is _ pole, and the second end of the detecting resistor is electrically connected to the second reference potential. 14. The liquid crystal display of claim 12, wherein the comparison unit comprises a comparator, wherein the two input ends respectively receive the reference voltage and the detection voltage, and the output of the comparator outputs The control signal. 15. The liquid crystal display of claim 14, wherein the comparison unit further comprises: 21 200816121 95103 19756 twf.doc/t one of; and, the first end is electrically connected to the second wheel of the comparator A feedback capacitor, the hairpin, and the feedback capacitor:; - = raw connection of the feedback resistor of the second 16 if the application is coupled to the wheel of the comparator. The variable __, where a f is off, its control terminal is used to receive the control signal, and the second resistor is connected in parallel with the switch; a second resistor is connected in series with the switch; When the voltage is depressed, the switch is intercepted by the reference voltage: the two 'ί::: the impedance of the variable impedance unit is the second impedance. The heart and the 丨 丨 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 高压 高压 高压 Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ Φ 第一 第一 第一 第一 第一 第一 第一 第一 第一 第一 第一 第一^—The secondary side is connected to the liquid crystal display according to item 16 of the light range, wherein the secondary side element is connected to the high voltage transformer and the light emitting unit is surrounded! Second, S liquid crystal display, where u extension &&, cold cathode officer, fluorescent lamp or halogen lamp. twenty two