200822017 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種背光模組及其調光方法，特別關於 一種結合振幅及脈衝模式（burst-mode)之調光功能之背光 模組及其調光方法。 【先前技術】 隨著數位時代的來臨，液晶顯示裝置之技術亦快速成 長’已成為不可或缺的電子產品，因此對於液晶顯示裝置 之技術及功能的要求也愈來愈高。 一般而言’液晶顯示裝置係主要包含一液晶顯示面板 (Liquid Crystal Display Panel )、以及一背光模組 (Backlight Module)。其中，液晶顯示面板係主要具有兩 基板、以及一夾設於兩基板間的液晶層；而背光模組係發 出均勻的光線以分佈在液晶顯示面板之表面，傳統上，係 以冷陰極營光燈（Cold Cathode Fluorescent Lamp，CCFL ) 來作為背光模組之光源，並藉由一換流器（inverter)來提 供冷陰極螢光燈所需之驅動訊號。近來，為了提升液晶顯 示裝置的色彩表現，以及降低背光滅組的功率消耗，背光 模組之調光功能及控制光源之發光強度已成為背光模組 不可或缺的技術之一。 請參照圖1所示，習知之一種背光模組i係包含一換 流器11、至少一發光單元12以及一控制單元13。換流器 11係具有一切換單元111及一變壓器112，其中切換單元 200822017 111係以一全橋式切換電路為例，且切換單元i i i係接收 例如為24伏特（v)之一直流電壓。控制單元u係分別 與切換單元111及發光單元12電性連接，並產生一組控制 訊5虎SO 1、SO 1以控制切換早元111 ’故切換單元1 η係接 收並依據此組控制訊號SOI、S01，而產生一切換訊號S02 至變壓器112,而變壓器112係依據切換訊號S02產生一 驅動訊號S03，以使發光單元12發光。在此種架構下，背 光模組1係可藉由改變切換頻率、切換導通率（duty-rat⑻ 或輸入換流器之直流電壓來達到調光之目的，且上述調光 方式一般係統稱為振幅調光。 然而，振幅調光方式卻會伴隨背光模組1之電源端的 電磁干擾(Electromagnetic Diterference，EMI)濾波器不易設 計、因切換單元無零電壓切換(zero v〇ltage switching，ZVs) 導致電路效率降低及輸入電壓24伏特而限制調光範圍等 限制，而綜合上述問題，則可知最大的影響為調光範圍不 大。 因此，如何提供一種具有高調光範圍之背光模組及其 調光方式，正是當前的重要課題之一。 【發明内容】 有鑑於上述課題，本發明之目的為提供一種具有高調 光範圍之背光模組及其調光方式。 緣是，為達上述目的，依據本發明之一種背光模組包 含一切換單元、一諧振轉換單元、一變壓器以及一發光單 200822017 元。切換單元係依據一第一控制訊號以產生一切換訊號； 諧振轉換單元電性連接切換單元以接收切換訊號，且諧振 轉換單元係具有一第一儲能元件及一開關元件，並依據一 第二控制訊號以控制開關元件，使諧振轉換單元產生一諧 振轉換訊號；變壓器係具有一次側繞組及二次側繞組，其 中一次側繞組電性連接諧振轉換單元及切換單元，而變壓 器係依據諧振轉換訊號及切換訊號，產生一驅動訊號；發 光單元電性連接二次侧繞組，並依據驅動訊號以驅動發光 17 口 一 早兀0 另外，為達上述目的，依據本發明之一種背光模組包 含一切換單元、一諧振轉換單元、一變壓器以及一發光單 元。切換單元係依據一第一控制訊號以產生一切換訊號； 諧振轉換單元係具有一第一儲能元件及一開關元件，並依 據一第二控制訊號以控制開關元件，並使諧振轉換單元產 生一諧振轉換訊號；變壓器具有一次側繞組及二次側繞 組，其中一次側繞組係與該切換單元電性連接，二次側繞 組係與諧振轉換單元電性連接，且變壓器係依據切換訊號 及諧振轉換訊號，產生一驅動訊號；發光單元電性連接諧 振轉換單元，並依據驅動訊號以驅動發光單元。 又，為達上述目的，依據本發明之一種背光模組之調 光方法，其中背光模組係具有一切換單元、一諧振轉換單 元、一變壓器以及一發光單元，變壓器係電性連接切換單 元、發光單元及諧振轉換單元，諧振轉換單元係具有一開 關元件，調光方法包括下列步驟：依據一第一控制訊號產 200822017 生一切換訊號；開啟開關元件，以產生一第一諧振轉換訊 號；依據切換訊號及第一諧振轉換訊號，產生第一驅動訊 號以驅動發光單元；關閉開關元件，以產生一第二諧振轉 換訊號；以及依據切換訊號及第二諧振轉換訊號，產生一 第二驅動訊號以驅動發光單元。 承上所述，因依據本發明之一種背光模組及其調光方 法，藉由諧振轉換單元與變壓器之一次側繞組或二次側繞 組電性連接，且變壓器係電性連接切換單元及一發光單 元，以使切換單元依據一第一控制訊號產生切換訊號，且 依據第二控制訊號以控制諧振轉換單元之開關元件，而產 生諧振轉換訊號，變壓器係依據切換訊號及諧振轉換訊號 產生驅動訊號，以驅動發光單元，並藉由開啟或關閉諧振 轉換單元之開關元件來調整驅動訊號的大小，以調整發光 單元的發光強度。與習知技術相較，背光模組係於變壓器 之一次側繞組或二次側繞組藉由串聯或並聯之電性連接 方式增加諧振轉換單元，並利用諧振轉換單元之開關元件 依據第二控制訊號以開啟或關閉，配合變壓器而產生驅動 訊號，此種方式，除了使背光模組同時具有振幅及脈衝模 式調光方式外，亦可將振幅及脈衝模式調光方式交互使 用，進而增加背光模組之調光範圍，當然亦解決了習知振 幅調光所帶來之缺點。 【實施方式】 以下將參照相關圖式，說明依本發明較佳實施例之一 200822017 種背光模組及其調光方法。 請參照圖2A所示，本發明第一較佳實施例之一種背 光模組2包含一切換單元21、一諧振轉換單元22、一變 壓器23以及一發光單元24。此外，本實施例之背光模組 2更包含一控制單元25。 於本實施例中，切換單元21係包含一橋式切換電路， 其係依據一第一控制訊號Sll、S11’以產生一切換訊號 512。 本實施例之橋式切換電路，於實施上係可為一全橋 式切換電路(如圖2A所示）或一半橋式切換電路（如圖2B所 示），在此係以全橋式切換電路為例，並據以將第一控制訊 號Sll、S11’轉換為切換訊號S12而輸出。 另外，第一控制訊號S11、S11’於實施上係由一組控 制訊號S11、S11’構成，並可由外部之一訊號產生單元或 由控制單元25產生，在此係以第一控制訊號Sll、S11’ 由控制單元25產生為例。其中，第一控制訊號Sll之相 位係與第一控制訊號S11’之相位相差180度，且於實施上 皆為一脈衝寬度調變（PWM)訊號。 於本實施例中，控制單元25係電性連接切換單元21、 諧振轉換單元22及發光單元24，並產生一第二控制訊號 513。 此外，本實施例之控制單元25係可為一控制器或一 控制晶片，而第二控制訊號S13於實施上係為一脈衝寬度 調變訊號；另外，第一控制訊號S11、S11’之頻率係大於 第二控制訊號S13,故第一控制訊號Sll、S11’係為一高頻 之脈衝寬度調變訊號，而第二控制訊號S13係為一低頻之 200822017 脈衝寬度調變訊號。換言之，藉由調整第二控制訊號S13， 即可執行所謂的脈衝模式調光。 請再參照圖2A與圖2B所示，本實施例之諧振轉換單 元22係具有一第一儲能元件221及一開關元件222,而諧 振轉換單元22係與切換單元21電性連接，以接收切換訊 號S12。此外，第一儲能元件221係與開關元件222相互 並聯電性連接，而諧振轉換單元22則依據第二控制訊號 S13以控制開關元件222關閉（即導通）或開啟（即不導通）， 而使諧振轉換單元22產生一諧振轉換訊號S14,其中，當 開關元件222依據第二控制訊號S13而關閉時，諧振轉換 單元22係產生一第一諧振轉換訊號；當開關元件222依 據第二控制訊號S13而開啟時，諧振轉換單元22係產生 一第二諧振轉換訊號，意即諧振轉換訊號S14係至少由第 一諧振轉換訊號及第二諧振轉換訊號所構成。本實施例之 開關元件222係可為一雙載子電晶體、一場效電晶體或一 電源繼電器（power-relay)。 於本實施例中，變壓器23係具有一次側繞組231及 二次側繞組232，而一次側繞組231係電性連接諧振轉換 單元22及切換單元21，而變壓器23係依據諧振轉換訊號 S14及切換訊號S12而產生一驅動訊號S15。而本實施例 之驅動訊號S15係由具有不同振幅Rl、R2之一第一驅動 訊號S15a及一第二驅動訊號S15b所構成（如圖3所示）； 且驅動訊號S15為一電流訊號，並具有一第一工作週期T1 及一第二工作週期T2，即第一驅動訊號S15a之週期係為 11 200822017 第一工作週期ΤΙ，而第二驅動訊號S15b之週期係為第二 工作週期T2 (如圖3所示）。另外，本實施例之變壓器23 及諧振轉換單元22於實施上係可構成一諧振網路。 此外，本實施例之諧振轉換單元22與變壓器23之一 次側繞組231之電性連接方式並無限制，其係可為串聯或 並聯。 當諧振轉換單元22與一次側繞組231並聯時（如圖 2A、圖2B與圖4A所示），諧振轉換單元22更包含一第二 儲能元件223，其係電性連接一次側繞組231、第一儲能 元件221及開關元件222，且其係與第一儲能元件221及 開關元件222串聯。本實施例之第一儲能元件221及第二 儲能元件223於實施上係為一電容器（如圖2A與圖2B所 示）或為一電感器（如圖4A所示）。 當諧振轉換單元22與一次側繞組231串聯時，第一 儲能元件221係為一電容器（如圖4B所示）或一電感器（如 圖4C所示）。 請再參照圖2A與圖2B所示，於本實施例中，發光單 元24電性連接變壓器23之二次側繞組232及控制單元 25，並依據驅動訊號S15以驅動發光單元24發光。本實 施例之發光單元24於實施上係為一冷陰極螢光燈管 (CCFL)，在此以一個發光單元24為例。 此外，發光單元24更產生一回授訊號S16並傳送至 控制單元25，以使控制單元25依據回授訊號S16而調整 輸出第一控制訊號Sll、S11’，以對發光單元24做補償。 12 200822017 另外，請再參照圖2A至圖2B及圖4A至圖4C所示， 背光模組2更包含一第三儲能元件26及一第四儲能元件 27，於實施上係分別為一電容器，本實施例中，第三儲能 元件26電性連接諧振轉換單元22,而第四儲能元件27電 性連接二次側繞組232及發光單元24，故第三儲能元件 26係用以濾除諧振轉換訊號S14之直流，第四儲能元件 27係用以穩定驅動訊號S15。 於本實施例中，背光模組2之調光方式，在此係以諧 振轉換單元22與變壓器23之一次側繞組231並聯，且第 一儲能元件221及第二儲能元件223皆為電容器為例（如圖 2A與圖2B所示），故背光模組2之調光方式如下：切換單 元21係接收及依據控制單元25所產生之第一控制訊號 Sll、S11’，以產生切換訊號S12，諧振轉換單元22係接 收切換訊號S12以及由控制單元25所產生之第二控制訊 號S13,當開關元件222依據第二控制訊號S13而關閉時， 則僅由第二儲能元件223作動，而產生第一諧振轉換訊 號，以使變壓器23依據切換訊號S12及諧振轉換訊號， 經由一次側繞組231及二次側繞組232而產生第一驅動訊 號S15a(如圖3所示），以驅動發光單元24;當開關元件222 依據第二控制訊號S13而開啟時，則第一儲能元件221及 第二儲能元件223係同時作動，以產生第二諧振轉換訊 號，以使變壓器23依據切換訊號S12及第二諧振轉換訊 號而產生第二驅動訊號S 15b(如圖3所示），以驅動發光單 元24。而發光單元24係產生回授訊號S16至控制單元25, 13 200822017 以使控制單元25依據回授訊號S16而調整第一控制訊號 Sll、S11’，以對發光單元24做補償。 當然，本實施例之諧振轉換單元22與變壓器23之一 次側繞組231之其他連接態樣（如圖4A至圖4C)皆與上述 調光方式具有相同功效，故於此不再贅述。 請再參照圖3所示，由上述背光模組2之調光方式之 作動可得知，本實施例之驅動訊號S15之第一驅動訊號 S15a及第二驅動訊號S15b的振幅Rl、R2大小，與第一 工作週期T1及第二工作週期T2之時間長短，係依據開關 元件222之開啟及關閉，並配合變壓器23經由諧振及轉 換做調整。 當然，本實施例之背光模組2之調光方式，係除了上 述方式之外，更可利用複數組諧振轉換單元並依據各開關 元件之開啟及關閉，而產生多種組合或交互使用之調光方 式，即具有多個不同振幅及多個不同工作週期之驅動訊號 (圖未示），以驅動發光單元，而可具有更多元的調光模式。 由於背光模組2係增加了諧振轉換單元22,並使諧振 轉換單元22電性連接變壓器23之一次側繞組231，故除 了可藉由諧振轉換單元22之開關元件222的開啟或關閉 並配合切換單元21及變壓器23,而具有振幅調光方式外， 更同時具有脈衝模式調光方式，且振幅及脈衝模式調光方 式係可交互使用，此種方式，除了可使背光模組2具有不 同功能的調光方式外，且使調光範圍更廣，而且諧振轉換 單元22係由簡單電路或元件所構成，故亦降低製造成本。 14 200822017 請參照圖5所示，本發明第二較佳實施例之一種背光 模組3係包含一切換單元31、一諧振轉換單元32、一變 壓器33以及一發光單元34。此外，本實施例之背光模組 3更包含一控制單元35。 本實施例之切換單元31係依據一第一控制訊號S21、 S21’以產生一切換訊號S22，且切換單元31於實施上係為 一橋式切換電路，在此係以切換單元31為全橋式切換電 路為例。此外，第一控制訊號S21、S21’係由一組相位相 差180度之控制訊號S21、S21’所構成，並可由外部之一 訊號產生單元或由控制單元35產生，在此則以第一控制 訊號S21、S21’由控制單元35產生為例。 本實施例之控制單元35係產生第一控制訊號S21、 S21’及第二控制訊號S23，並電性連接切換單元31、諧振 轉換單元32及發光單元34。 此外，本實施例之第一控制訊號S21、S21’及第二控 制訊號S23皆為一脈衝寬度調變訊號，且第一控制訊號 S21、S21’之頻率係大於第二控制訊號S23之頻率，故第 一控制訊號S21、S21’係為一高頻脈衝寬度調變訊號，而 第二控制訊號S23係為一低頻脈衝寬度調變訊號。 請再參照圖5所示，本實施例之諧振轉換單元32係 具有一第一儲能元件321件及一開關元件322，並接收第 二控制訊號S23,而諧振轉換單元32係依據第二控制訊號 S23以控制開關元件322之開啟或關閉，使諧振轉換單元 32產生一諧振轉換訊號S24。此外，本實施例之第一儲能 15 200822017 元件321及開關元件322係相互並聯電性連接。 本實施例之變壓器33，係具有一次側繞組331及二次 側繞組332，而一次側繞組331係與切換單元31電性連 接，而二次側繞組332係與諧振轉換單元32電性連接， 故變壓器33係依據切換訊號S22及諧振轉換訊號S24以 產生一驅動訊號S25。其中，本實施例之諧振轉換單元32 與變壓器33之二次側繞組332之連接方式並無限制，係 可為串聯或並聯。 當諧振轉換單元32係與二次側繞組332為並聯時（如 圖5所示），諧振轉換單元32係包括一第二儲能元件323， 其係電性連接二次側繞組332、第一儲能元件321及開關 元件322，且與第一儲能元件321及開關元件322相互串 聯，而本實施例之第一儲能元件321及第二儲能元件323 於實施上係可為一電容器（如圖5所示）或一電感器（如圖 6 A所示）。 當諧振轉換單元32係與二次側繞組332串聯時，則 第一儲能元件321係可為一電容器（如圖6B所示）或一電感 器（如圖6C所示）。 本實施例之發光單元34電性連接變壓器33之二次側 繞組332及諧振轉換單元32，並接收驅動訊號S25，以驅 動發光單元34，並藉由諧振轉換單元32之開關元件322 之開啟及關閉來調整驅動訊號S25的大小，使發光單元34 得以依據驅動訊號S25調整發光強度，而發光單元34係 產生一回授訊號S26至控制單元35，以使控制單元35依 16 200822017 據回授訊號S26而調整第一控制訊號S21、S21’，以對發 光單元34做補償。 另外，請再參照圖5至圖6C所示，背光模組3更包 含一第三儲能元件36及一第四儲能元件37，於實施上係 可分別為一電容器，且第三儲能元件36係用以濾除諧振 轉換訊號S24之直流，第四儲能元件37係用以穩定驅動 訊號S25。 於本實施例中，切換單元31、控制單元35、第一控 制訊號S21、S21’、第二控制訊號S23、開關元件322、發 光單元34、驅動訊號S25、第三儲能元件36及第四儲能 元件37係與上述第一較佳實施例（如圖2A所示）之切換單 元21、控制單元25、第一控制訊號Sll、S11’、第二控制 訊號S13、開關元件222、發光單元24、第三儲能元件26 及第四儲能元件27具有相同構成、特徵及功效，故於此 不再贅述。 請參照圖7所示，本發明較佳實施例之一種背光模組 之調光方法係應用於上述第一及第二較佳實施例之背光 模組2、3(如圖2A及圖5所示），且在此係以第一較佳實 施例之背光模組2為例。 請再參照圖2A所示，本實施例之背光模組2,係具有 一切換單元21、一諧振轉換單元22、一變壓器23以及一 發光單元24，而變壓器23電性連接切換單元21、發光單 元24及諧振轉換單元22,且諧振轉換單元22係電性連接 於切換單元21及變壓器23之間；而諧振轉換單元22係 (5 > 17 200822017 具有一第一儲能元件221及一開關元件222。此外，背光 模組2更具有一控制單元25，其係分別與切換單元21、 諧振轉換單元22及發光單元24電性連接。其中，背光模 組之調光方式，係包括步驟S1至S5。 步驟S1，係依據一組第一控制訊號，產生一切換訊 號；步驟S2,係開啟開關元件，以產生一第一諧振轉換訊 號；步驟S3，係依據切換訊號及第一諧振轉換訊號，而產 生第一驅動訊號以驅動發光單元；步驟S4，係關閉開關元 件，以產生一第二諧振轉換訊號；以及步驟S5，係依據切 換訊號及第二諧振轉換訊號，而產生第二驅動訊號以驅動 發光單元。 其中詳細的調光步驟，於上述第一較佳實施例及第二 較佳實施例中，已一併詳述，故於此不再加以贅述。 綜上所述，因依據本發明之一種背光模組及其調光方 式，藉由一諳振轉換單元與一變壓器之一次側繞組或二次 側繞組電性連接，且變壓器係電性連接切換單元及發光單 元，以使切換單元依據第一控制訊號產生切換訊號，且依 據第二控制訊號以控制諧振轉換單元之開關元件，而產生 諧振轉換訊號，變壓器則係依據切換訊號及諧振轉換訊號 產生驅動訊號，以驅動發光單元，並藉由開啟或關閉諧振 轉換單元之開關元件來調整驅動訊號的大小，以調整發光 單元之發光強度。與習知技術相較，背光模組係於變壓器 之一次側繞組或二次側繞組藉由串聯或並聯之電性連接 方式增加諧振轉換單元，並利用諧振轉換單元之開關元件 18 200822017 依據第二控制訊號以開啟或關閉，配合變壓器而產生驅動 訊號，此種方式，除了使背光模組同時具有振幅及脈衝模 式調光方式外，亦可將振幅及脈衝模式調光方式交互使 用，進而增加背光模組之調光範圍，當然亦解決了習知振 幅調光所帶來之缺點。另外，由於諧振轉換單元係由簡單 電路或元件所構成，故更可降低製造成本。 以上所述僅為舉例性，而非為限制性者。任何未脫離 本發明之精神與範疇，而對其進行之等效修改或變更，均 應包含於後附之申請專利範圍中。 【圖式簡單說明】 圖1為顯示習知之一種背光模組之示意圖； 圖2A至圖2B為顯示依本發明第一較佳實施例之一種 背光模組之示意圖，其中圖2A係顯示切換單元係為一全 橋式切換電路，圖2B係顯示切換單元係為一半橋式切換 電路； 圖3為顯示依本發明第一較佳實施例之背光模組之驅 動訊號所具有之振幅及第一工作時間與第二工作時間之 示意圖； 圖4A至4C為顯示依本發明第一較佳實施例之其他諧 振轉換單元與變壓器之一次側繞組之連接方式之示意圖； 圖5為顯示依本發明第二較佳實施例之一種背光模組 之不意圖， 圖6 A至6 C為顯示依本發明第二較佳實施例之其他諧 200822017 振轉換單元與變壓器之二次側繞組之連接方式之示意 圖；以及 圖7為顯示依本發明較佳實施例之背光模組之調光方 法之流程圖。 元件符號說明： 1、2、3 :背光模組 11 ： 換流 器 111 、21、 31 :切換單元 112 、23、 33 :變壓器 12、 24、 34 :發光單元 13 ^ 25、 35 :控制單元 XI、 32 ： 諧振轉換單元 221 、321 :第一儲能元件 222 、322 :開關元件 223 、323 :第二儲能元件 231 、331 :一次側繞組 232 、332 :二次側繞組 26 ^ 36 ： 第三儲能元件 27、 37 ： 第四儲能元件 R1、 R2 ： 振幅 S01 > S01 ’：控制訊號 S02 :切換訊號 S03 、S15 、S25 :驅動訊號 20 200822017 511、 Sir、S21、S21，：第一控制訊號 512、 S22 :切換訊號 513、 S23 ··第二控制訊號 514、 S24 :諧振轉換訊號 S15 a :第一驅動訊號 S15b :第二驅動訊號 S16、S26 :回授訊號 T1 :第一工作週期 T2 :第二工作週期 S1-S5:背光模組之調光方法之步驟 21200822017 IX. Description of the Invention: [Technical Field] The present invention relates to a backlight module and a dimming method thereof, and more particularly to a backlight module combining amplitude and pulse-mode dimming function and Dimming method. [Prior Art] With the advent of the digital age, the technology of liquid crystal display devices has also rapidly grown into an indispensable electronic product, and thus the requirements for the technology and function of liquid crystal display devices have become higher and higher. Generally, a liquid crystal display device mainly includes a liquid crystal display panel and a backlight module. The liquid crystal display panel mainly has two substrates and a liquid crystal layer sandwiched between the two substrates; and the backlight module emits uniform light to be distributed on the surface of the liquid crystal display panel. Traditionally, the cold cathode camp light is used. A Cold Cathode Fluorescent Lamp (CCFL) is used as a light source for the backlight module, and an inverter is used to provide a driving signal required for the cold cathode fluorescent lamp. Recently, in order to improve the color performance of the liquid crystal display device and reduce the power consumption of the backlight group, the dimming function of the backlight module and the illumination intensity of the control light source have become one of the indispensable technologies for the backlight module. Referring to FIG. 1 , a conventional backlight module i includes an inverter 11 , at least one light emitting unit 12 , and a control unit 13 . The inverter 11 has a switching unit 111 and a transformer 112. The switching unit 200822017 111 is exemplified by a full bridge switching circuit, and the switching unit i i receives a DC voltage of, for example, 24 volts (v). The control unit u is electrically connected to the switching unit 111 and the light-emitting unit 12, respectively, and generates a set of control signals 5 Tiger SO 1 and SO 1 to control the switching early element 111. Therefore, the switching unit 1 η receives and controls the signal according to the group. The SOI, S01 generates a switching signal S02 to the transformer 112, and the transformer 112 generates a driving signal S03 according to the switching signal S02 to cause the lighting unit 12 to emit light. In this architecture, the backlight module 1 can achieve dimming by changing the switching frequency, switching the conduction rate (duty-rat (8) or the DC voltage of the input converter, and the above dimming mode is generally called amplitude. However, the amplitude dimming method is accompanied by the electromagnetic interference of the power supply terminal of the backlight module 1 (Electromagnetic Diterference (EMI) filter is not easy to design, and the switching unit has no zero voltage switching (ZVs). The efficiency is reduced and the input voltage is 24 volts and the dimming range is limited. When the above problems are integrated, the maximum effect is that the dimming range is not large. Therefore, how to provide a backlight module with a high dimming range and its dimming method In view of the above problems, an object of the present invention is to provide a backlight module having a high dimming range and a dimming method thereof. The edge is that, in order to achieve the above object, according to the present invention The invention relates to a backlight module comprising a switching unit, a resonant conversion unit, a transformer and a luminous single 200822017 yuan. The unit is configured to generate a switching signal according to a first control signal; the resonant conversion unit is electrically connected to the switching unit to receive the switching signal, and the resonant conversion unit has a first energy storage element and a switching element, and according to a second control The signal is used to control the switching element to cause the resonant conversion unit to generate a resonant switching signal; the transformer has a primary side winding and a secondary side winding, wherein the primary side winding is electrically connected to the resonant conversion unit and the switching unit, and the transformer is based on the resonant conversion signal and Switching the signal to generate a driving signal; the light-emitting unit is electrically connected to the secondary winding, and driving the light-emitting port 17 according to the driving signal. The backlight module includes a switching unit according to the present invention. a resonant conversion unit, a transformer, and an illumination unit. The switching unit generates a switching signal according to a first control signal; the resonant conversion unit has a first energy storage component and a switching component, and is based on a second control signal To control the switching elements and cause the resonant conversion unit to generate a harmonic The conversion signal has a primary side winding and a secondary side winding, wherein the primary side winding is electrically connected to the switching unit, the secondary side winding is electrically connected to the resonant conversion unit, and the transformer is based on the switching signal and the resonant conversion signal. And generating a driving signal; the light emitting unit is electrically connected to the resonant converting unit, and driving the light emitting unit according to the driving signal. Further, in order to achieve the above object, according to the dimming method of the backlight module of the present invention, the backlight module has a switching unit, a resonant conversion unit, a transformer and an illumination unit, the transformer is electrically connected to the switching unit, the illumination unit and the resonance conversion unit, and the resonance conversion unit has a switching element, and the dimming method comprises the following steps: a control signal is generated in 200822017 to generate a switching signal; the switching element is turned on to generate a first resonant conversion signal; the first driving signal is generated to drive the light emitting unit according to the switching signal and the first resonant switching signal; and the switching element is turned off to generate a Second resonant conversion signal; And the second resonant conversion signal generates a second driving signal to drive the light emitting unit. According to the present invention, a backlight module and a dimming method thereof are electrically connected to a primary winding or a secondary winding of a transformer by a resonant conversion unit, and the transformer is electrically connected to the switching unit and the first a light-emitting unit, wherein the switching unit generates a switching signal according to a first control signal, and controls a switching element of the resonant conversion unit according to the second control signal to generate a resonant conversion signal, and the transformer generates a driving signal according to the switching signal and the resonant conversion signal To drive the light-emitting unit and adjust the size of the driving signal by turning on or off the switching element of the resonant conversion unit to adjust the luminous intensity of the light-emitting unit. Compared with the prior art, the backlight module is connected to the primary side winding or the secondary side winding of the transformer to increase the resonant conversion unit by means of electrical connection in series or parallel, and the switching element of the resonant conversion unit is used according to the second control signal. In order to open or close, the driver generates a driving signal. In addition to the amplitude and pulse mode dimming mode of the backlight module, the amplitude and pulse mode dimming modes can be used interchangeably to increase the backlight module. The dimming range, of course, also solves the shortcomings of conventional amplitude dimming. [Embodiment] Hereinafter, a backlight module of 200822017 and a dimming method thereof according to a preferred embodiment of the present invention will be described with reference to related drawings. Referring to FIG. 2A, a backlight module 2 according to a first preferred embodiment of the present invention includes a switching unit 21, a resonant conversion unit 22, a transformer 23, and a lighting unit 24. In addition, the backlight module 2 of the embodiment further includes a control unit 25. In this embodiment, the switching unit 21 includes a bridge switching circuit for generating a switching signal 512 according to a first control signal S11, S11'. The bridge switching circuit of this embodiment may be a full bridge switching circuit (as shown in FIG. 2A) or a half bridge switching circuit (shown in FIG. 2B), which is a full bridge switching. The circuit is taken as an example, and the first control signals S11, S11' are converted into switching signals S12 for output. In addition, the first control signals S11, S11' are implemented by a group of control signals S11, S11', and can be generated by an external signal generating unit or by the control unit 25, where the first control signal S11, S11' is generated by the control unit 25 as an example. The phase of the first control signal S11 is 180 degrees out of phase with the first control signal S11', and is implemented as a pulse width modulation (PWM) signal. In this embodiment, the control unit 25 electrically connects the switching unit 21, the resonant conversion unit 22, and the illumination unit 24, and generates a second control signal 513. In addition, the control unit 25 of the embodiment may be a controller or a control chip, and the second control signal S13 is implemented as a pulse width modulation signal; in addition, the frequency of the first control signals S11, S11' The first control signal S11, S11' is a high frequency pulse width modulation signal, and the second control signal S13 is a low frequency 200822017 pulse width modulation signal. In other words, by adjusting the second control signal S13, so-called pulse mode dimming can be performed. Referring to FIG. 2A and FIG. 2B , the resonant converter unit 22 of the present embodiment has a first energy storage component 221 and a switching component 222 , and the resonant converter unit 22 is electrically connected to the switching unit 21 to receive Switch signal S12. In addition, the first energy storage component 221 and the switching component 222 are electrically connected in parallel with each other, and the resonant conversion unit 22 controls the switching component 222 to be turned off (ie, turned on) or turned on (ie, not turned on) according to the second control signal S13. The resonant switching unit 22 generates a resonant switching signal S14, wherein when the switching element 222 is turned off according to the second control signal S13, the resonant converting unit 22 generates a first resonant switching signal; when the switching element 222 is in accordance with the second control signal When S13 is turned on, the resonant conversion unit 22 generates a second resonant switching signal, that is, the resonant switching signal S14 is formed by at least the first resonant converted signal and the second resonant converted signal. The switching element 222 of this embodiment can be a dual carrier transistor, a field effect transistor or a power-relay. In the present embodiment, the transformer 23 has a primary winding 231 and a secondary winding 232, and the primary winding 231 is electrically connected to the resonant converter unit 22 and the switching unit 21, and the transformer 23 is switched according to the resonant switching signal S14. A driving signal S15 is generated by the signal S12. The driving signal S15 of the embodiment is composed of a first driving signal S15a and a second driving signal S15b having different amplitudes R1 and R2 (as shown in FIG. 3); and the driving signal S15 is a current signal, and Having a first duty cycle T1 and a second duty cycle T2, that is, the period of the first driving signal S15a is 11 200822017 first working period ΤΙ, and the period of the second driving signal S15b is the second working period T2 (eg Figure 3). In addition, the transformer 23 and the resonant converter unit 22 of the present embodiment can constitute a resonant network. In addition, the electrical connection manner between the resonant converter unit 22 of the present embodiment and one of the secondary windings 231 of the transformer 23 is not limited, and may be serial or parallel. When the resonant converter unit 22 is connected in parallel with the primary winding 231 (as shown in FIG. 2A, FIG. 2B and FIG. 4A), the resonant converter unit 22 further includes a second energy storage component 223 electrically connected to the primary winding 231, The first energy storage element 221 and the switching element 222 are connected in series with the first energy storage element 221 and the switching element 222. The first energy storage component 221 and the second energy storage component 223 of this embodiment are implemented as a capacitor (as shown in Figures 2A and 2B) or as an inductor (as shown in Figure 4A). When the resonant converter unit 22 is connected in series with the primary side winding 231, the first energy storage element 221 is a capacitor (as shown in Figure 4B) or an inductor (as shown in Figure 4C). Referring to FIG. 2A and FIG. 2B again, in the embodiment, the light-emitting unit 24 is electrically connected to the secondary winding 232 of the transformer 23 and the control unit 25, and drives the light-emitting unit 24 to emit light according to the driving signal S15. The illumination unit 24 of the present embodiment is implemented as a cold cathode fluorescent lamp (CCFL), and an illumination unit 24 is exemplified herein. In addition, the illumination unit 24 further generates a feedback signal S16 and transmits it to the control unit 25, so that the control unit 25 adjusts and outputs the first control signals S11, S11' according to the feedback signal S16 to compensate the illumination unit 24. 12 200822017 In addition, as shown in FIG. 2A to FIG. 2B and FIG. 4A to FIG. 4C , the backlight module 2 further includes a third energy storage component 26 and a fourth energy storage component 27 , which are respectively implemented as one. In the present embodiment, the third energy storage component 26 is electrically connected to the resonant converter unit 22, and the fourth energy storage component 27 is electrically connected to the secondary side winding 232 and the light emitting unit 24. Therefore, the third energy storage component 26 is used. To filter out the DC of the resonant conversion signal S14, the fourth energy storage component 27 is used to stabilize the driving signal S15. In this embodiment, the dimming mode of the backlight module 2 is in this case, the resonant conversion unit 22 is connected in parallel with the primary winding 231 of the transformer 23, and the first energy storage component 221 and the second energy storage component 223 are capacitors. For example, as shown in FIG. 2A and FIG. 2B, the dimming mode of the backlight module 2 is as follows: the switching unit 21 receives and controls the first control signals S11 and S11' generated by the control unit 25 to generate a switching signal. S12, the resonant conversion unit 22 receives the switching signal S12 and the second control signal S13 generated by the control unit 25, and when the switching element 222 is turned off according to the second control signal S13, only the second energy storage element 223 is activated. The first resonant conversion signal is generated, so that the transformer 23 generates the first driving signal S15a (shown in FIG. 3) via the primary winding 231 and the secondary winding 232 according to the switching signal S12 and the resonant switching signal to drive the light. When the switching element 222 is turned on according to the second control signal S13, the first energy storage element 221 and the second energy storage element 223 are simultaneously activated to generate a second resonant conversion signal, so that the transformer 23 is The second driving signal S 15b (shown in FIG. 3) is generated according to the switching signal S12 and the second resonant conversion signal to drive the light emitting unit 24. The illumination unit 24 generates the feedback signal S16 to the control unit 25, 13 200822017 to cause the control unit 25 to adjust the first control signals S11, S11' according to the feedback signal S16 to compensate the illumination unit 24. Of course, the other connection modes of the resonant switching unit 22 of the present embodiment and one of the secondary windings 231 of the transformer 23 (as shown in FIGS. 4A to 4C) have the same functions as the above-mentioned dimming mode, and thus will not be described herein. Referring to FIG. 3, the amplitudes of the first driving signal S15a and the second driving signal S15b of the driving signal S15 of the driving signal S15 of the present embodiment can be determined by the operation of the dimming mode of the backlight module 2. The length of time between the first duty cycle T1 and the second duty cycle T2 is adjusted according to the opening and closing of the switching element 222, and is matched with the transformer 23 via resonance and conversion. Of course, the dimming mode of the backlight module 2 of the embodiment is in addition to the above manner, and the multi-array resonant conversion unit can be utilized, and various combinations or interactive dimming can be generated according to the opening and closing of each switching element. The mode, that is, a driving signal (not shown) having a plurality of different amplitudes and a plurality of different duty cycles to drive the light emitting unit, and having a dimming mode of more elements. Since the backlight module 2 adds the resonant conversion unit 22 and electrically connects the resonant conversion unit 22 to the primary winding 231 of the transformer 23, the switching element 222 of the resonant conversion unit 22 can be switched on or off and switched. The unit 21 and the transformer 23 have an amplitude dimming mode and a pulse mode dimming mode, and the amplitude and pulse mode dimming modes can be used interchangeably. In addition, the backlight module 2 can have different functions. In addition to the dimming mode, and the dimming range is wider, and the resonant converter unit 22 is composed of a simple circuit or component, the manufacturing cost is also reduced. Referring to FIG. 5, a backlight module 3 according to a second preferred embodiment of the present invention includes a switching unit 31, a resonant conversion unit 32, a transformer 33, and a light emitting unit 34. In addition, the backlight module 3 of the embodiment further includes a control unit 35. The switching unit 31 of the present embodiment generates a switching signal S22 according to a first control signal S21, S21', and the switching unit 31 is implemented as a bridge switching circuit, wherein the switching unit 31 is a full bridge type. The switching circuit is taken as an example. In addition, the first control signals S21, S21' are formed by a group of control signals S21, S21' whose phases are 180 degrees out of phase, and can be generated by an external signal generating unit or by the control unit 35, where the first control is performed. The signals S21, S21' are generated by the control unit 35 as an example. The control unit 35 of the present embodiment generates the first control signals S21, S21' and the second control signal S23, and is electrically connected to the switching unit 31, the resonance conversion unit 32, and the light-emitting unit 34. In addition, the first control signals S21, S21' and the second control signal S23 of the embodiment are all a pulse width modulation signal, and the frequency of the first control signals S21, S21' is greater than the frequency of the second control signal S23. Therefore, the first control signals S21, S21' are a high frequency pulse width modulation signal, and the second control signal S23 is a low frequency pulse width modulation signal. Referring to FIG. 5 again, the resonant converter unit 32 of the present embodiment has a first energy storage component 321 and a switching component 322, and receives a second control signal S23, and the resonant conversion unit 32 is based on the second control. The signal S23 controls the switching element 322 to turn on or off, so that the resonant converter unit 32 generates a resonant switching signal S24. In addition, the first energy storage 15 200822017 element 321 and the switching element 322 of the embodiment are electrically connected in parallel with each other. The transformer 33 of the present embodiment has a primary side winding 331 and a secondary side winding 332, and the primary side winding 331 is electrically connected to the switching unit 31, and the secondary side winding 332 is electrically connected to the resonant conversion unit 32. Therefore, the transformer 33 generates a driving signal S25 according to the switching signal S22 and the resonant switching signal S24. The connection between the resonant converter unit 32 of the present embodiment and the secondary winding 332 of the transformer 33 is not limited, and may be series or parallel. When the resonant converter unit 32 is connected in parallel with the secondary winding 332 (as shown in FIG. 5), the resonant converter unit 32 includes a second energy storage component 323 electrically connected to the secondary winding 332, first. The energy storage component 321 and the switching component 322 are connected in series with the first energy storage component 321 and the switching component 322, and the first energy storage component 321 and the second energy storage component 323 of the embodiment may be a capacitor. (as shown in Figure 5) or an inductor (as shown in Figure 6A). When the resonant converter unit 32 is in series with the secondary winding 332, the first energy storage component 321 can be a capacitor (as shown in Figure 6B) or an inductor (as shown in Figure 6C). The light-emitting unit 34 of the embodiment is electrically connected to the secondary winding 332 of the transformer 33 and the resonant converter unit 32, and receives the driving signal S25 to drive the light-emitting unit 34, and is turned on by the switching element 322 of the resonant converter unit 32. The control unit 35 generates a feedback signal S26 to the control unit 35, so that the control unit 35 can respond to the signal according to the 16 200822017, the illumination unit 34 can adjust the illumination intensity according to the driving signal S25. S26 adjusts the first control signals S21, S21' to compensate the light-emitting unit 34. In addition, as shown in FIG. 5 to FIG. 6C , the backlight module 3 further includes a third energy storage component 36 and a fourth energy storage component 37 , which are respectively implemented as a capacitor and a third energy storage device. The component 36 is for filtering the DC of the resonant conversion signal S24, and the fourth energy storage component 37 is for stabilizing the driving signal S25. In this embodiment, the switching unit 31, the control unit 35, the first control signals S21, S21', the second control signal S23, the switching element 322, the light emitting unit 34, the driving signal S25, the third energy storage element 36, and the fourth The energy storage component 37 is a switching unit 21, the control unit 25, the first control signals S11, S11', the second control signal S13, the switching element 222, and the light emitting unit of the first preferred embodiment (shown in FIG. 2A). 24. The third energy storage component 26 and the fourth energy storage component 27 have the same configuration, features, and effects, and thus are not described herein. Referring to FIG. 7 , a dimming method of a backlight module according to a preferred embodiment of the present invention is applied to the backlight modules 2 and 3 of the first and second preferred embodiments (as shown in FIG. 2A and FIG. 5 ). The backlight module 2 of the first preferred embodiment is taken as an example. Referring to FIG. 2A again, the backlight module 2 of the embodiment has a switching unit 21, a resonant conversion unit 22, a transformer 23 and a light-emitting unit 24, and the transformer 23 is electrically connected to the switching unit 21 and emits light. The unit 24 and the resonant converter unit 22, and the resonant converter unit 22 is electrically connected between the switching unit 21 and the transformer 23; and the resonant converter unit 22 (5 > 17 200822017 has a first energy storage element 221 and a switch The 222 is further provided with a control unit 25, which is electrically connected to the switching unit 21, the resonant conversion unit 22, and the illuminating unit 24. The dimming mode of the backlight module includes the step S1. Step S1, generating a switching signal according to a set of first control signals; step S2, turning on the switching element to generate a first resonant switching signal; and step S3, according to the switching signal and the first resonant switching signal a first driving signal is generated to drive the light emitting unit; in step S4, the switching element is turned off to generate a second resonant switching signal; and step S5 is based on the switching signal and the second Resonating the signal to generate a second driving signal to drive the light emitting unit. The detailed dimming step has been described in detail in the first preferred embodiment and the second preferred embodiment, and thus is no longer In summary, a backlight module according to the present invention and a dimming method thereof are electrically connected to a primary side winding or a secondary side winding of a transformer by a vibration conversion unit, and the transformer is electrically connected. The switching unit and the lighting unit are connected to each other, so that the switching unit generates the switching signal according to the first control signal, and controls the switching element of the resonant conversion unit according to the second control signal to generate a resonant conversion signal, and the transformer is based on the switching signal and the resonance. The conversion signal generates a driving signal to drive the light-emitting unit, and adjusts the size of the driving signal by turning on or off the switching element of the resonant conversion unit to adjust the luminous intensity of the light-emitting unit. Compared with the prior art, the backlight module is tied to The primary side winding or the secondary side winding of the transformer is added to the resonant conversion unit by electrical connection in series or in parallel. The switching element 18 of the resonant conversion unit is used to turn on or off according to the second control signal, and the driving signal is generated by the transformer. In this way, in addition to the amplitude and pulse mode dimming mode of the backlight module, the amplitude can also be used. The pulse mode dimming mode is used interchangeably to increase the dimming range of the backlight module, and of course, the disadvantages caused by the conventional amplitude dimming are also solved. In addition, since the resonant conversion unit is composed of a simple circuit or component, The above description is only for the purpose of illustration and not limitation, and any equivalent modifications and changes may be included in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a conventional backlight module; FIG. 2A to FIG. 2B are schematic diagrams showing a backlight module according to a first preferred embodiment of the present invention, wherein FIG. 2A The display switching unit is a full bridge switching circuit, and FIG. 2B shows that the switching unit is a half bridge switching circuit; FIG. 4A to FIG. 4C are diagrams showing other resonant transitions according to the first preferred embodiment of the present invention; FIG. 4A to FIG. 4C are diagrams showing the amplitude of the driving signal of the backlight module of the first preferred embodiment; FIG. FIG. 5 is a schematic diagram showing a backlight module according to a second preferred embodiment of the present invention, and FIGS. 6A to 6C are diagrams showing a second preferred embodiment of the present invention. A schematic diagram of the connection mode of the other harmonics of the 200822017 vibration conversion unit and the secondary winding of the transformer; and FIG. 7 is a flow chart showing the dimming method of the backlight module according to the preferred embodiment of the present invention. Description of component symbols: 1, 2, 3: backlight module 11: inverters 111, 21, 31: switching unit 112, 23, 33: transformers 12, 24, 34: lighting unit 13^25, 35: control unit XI 32: Resonant conversion unit 221, 321 : first energy storage element 222 , 322 : switching element 223 , 323 : second energy storage element 231 , 331 : primary side winding 232 , 332 : secondary side winding 26 ^ 36 : Three energy storage elements 27, 37: Fourth energy storage elements R1, R2: amplitude S01 > S01 ': control signal S02: switching signals S03, S15, S25: drive signal 20 200822017 511, Sir, S21, S21,: A control signal 512, S22: switching signal 513, S23 · second control signal 514, S24: resonant conversion signal S15 a: first driving signal S15b: second driving signal S16, S26: feedback signal T1: first work Cycle T2: second duty cycle S1-S5: step 21 of the dimming method of the backlight module