1260454 九、發明說明： 【發明所屬之技術領域】 本發明係提供一種背光模組，尤指一種可提供穩定光線 之背光模組。 【先前技術】 液晶顯示面板主要是利用成矩陣狀排列的電晶體，配合 適當的電容、轉接墊等電子元件來驅動液晶像素，以產生 豐富亮麗的圖形。由於液晶顯示面板具有外型輕薄、耗電 量少以及無輻射污染等特性，因此被廣泛地應用在筆記型 電腦、個人數位助理等攜帶式資訊產品上，甚至已有逐漸 取代傳統桌上型電腦之CRT監視器（Cathode Ray Tube, CRT)及傳統電視的趨勢。 一般而言，液晶顯示器的背光模組係設於液晶顯示面板 的下方或側面，並利用至少一光源與各種光學元件（如擴散 板、稜鏡等）的組合，以提供液晶顯示面板高亮度且均勻之 光源，然後再藉由控制液晶顯示面板上的像素電極以形成 適當的色彩，進而構成液晶顯示器使用者所觀察到之亮麗 影像。 5 1260454 請參考第1圖，第1圖為一習知背光模組10之示意圖。 如第1圖所示，背光模組10係設於一液晶顯示面板12的 下方，並包含有至少一光源14、一擴散板16設於光源14 與液晶顯示面板12之間，以及一反射板18設於光源14下 方並固定於一金屬殼體20上。其中，光源14係用來提供 一光源至液晶顯示面板12，反射板18係用於將光源14所 產生的光線向液晶顯示面板12反射，以增加光的使用率， 進而提供一較佳之亮度輸出，擴散板16可將通過擴散板 16的光線進一步散射，以提供液晶顯示面板12較均勻分 散之光線。而設於反射板18下方並包覆反射板18周圍的 金屬殼體20，則是用來固定擴散板16、反射板18以及光 源14 〇 一般而言，背光模組10中的光源14大多是由一冷陰 極螢光燈管（cold cathode fluorescent lamp，CCFL)所構 成，而光源14往往係利用交流電加以驅動。請參閱第2圖， 第2圖係習知光源14以一交流電源所驅動之示意圖。交流 電源係由一電壓轉換器22與一電源26所組成。由於電壓 轉換器22之一次侧由電源26供電後，其二次侧會輸出一 交流電予光源14。由於光源14與金屬殼體20(繪示於第1 圖）之間的電容效應，因此導致漏電流（leakage current)的產 12604541260454 IX. Description of the Invention: [Technical Field] The present invention provides a backlight module, and more particularly to a backlight module that can provide stable light. [Prior Art] The liquid crystal display panel mainly uses a transistor arranged in a matrix to drive liquid crystal pixels with appropriate electronic components such as capacitors and transfer pads to produce rich and beautiful patterns. Because the liquid crystal display panel has the characteristics of thin and light appearance, low power consumption and no radiation pollution, it is widely used in portable information products such as notebook computers and personal digital assistants, and has even gradually replaced traditional desktop computers. The trend of CRT monitors (CRT) and traditional TV. Generally, the backlight module of the liquid crystal display is disposed under or on the side of the liquid crystal display panel, and uses at least one light source in combination with various optical components (such as a diffusion plate, a crucible, etc.) to provide high brightness of the liquid crystal display panel. A uniform light source is then formed by controlling the pixel electrodes on the liquid crystal display panel to form an appropriate color, thereby constituting a bright image observed by the user of the liquid crystal display. 5 1260454 Please refer to FIG. 1 , which is a schematic diagram of a conventional backlight module 10 . As shown in FIG. 1 , the backlight module 10 is disposed under a liquid crystal display panel 12 and includes at least one light source 14 , a diffusion plate 16 disposed between the light source 14 and the liquid crystal display panel 12 , and a reflective plate. 18 is disposed under the light source 14 and is fixed to a metal casing 20. The light source 14 is used to provide a light source to the liquid crystal display panel 12. The reflector 18 is used to reflect the light generated by the light source 14 to the liquid crystal display panel 12 to increase the light usage rate, thereby providing a better brightness output. The diffusing plate 16 can further scatter the light passing through the diffusing plate 16 to provide a relatively uniform dispersion of the liquid crystal display panel 12. The metal casing 20 disposed under the reflector 18 and surrounding the reflector 18 is used to fix the diffuser 16, the reflector 18, and the light source 14. In general, the light source 14 in the backlight module 10 is mostly It consists of a cold cathode fluorescent lamp (CCFL), and the light source 14 is often driven by alternating current. Please refer to FIG. 2, which is a schematic diagram of the conventional light source 14 driven by an alternating current power source. The AC power source is composed of a voltage converter 22 and a power source 26. Since the primary side of the voltage converter 22 is powered by the power source 26, an alternating current is supplied to the light source 14 on the secondary side. Due to the capacitive effect between the light source 14 and the metal casing 20 (shown in Figure 1), the leakage current is produced. 1260454
生，這麼一來，不僅會造成功率損失(power loss)，而且光 源14的兩端所發出的光線亮度也會不平均。為了避免這個 問題，請參閱第3圖以及第4圖，第3圖係光源14與電壓 轉換器22a、22b之示意圖，第4圖係施加於節點a、b之 電壓以及施加於光源14之跨壓之電壓關係圖。光源14兩 端分別電連接二電壓轉換器22a、22b，而這兩個獨立的電 壓轉換器22a、22b則分別連接於不同的電源26a、26b。一 般來說，光源14的兩端係分別連接於電壓轉換器22a、22b 之二次側，且電壓轉換器22a、22b之二次侧之極性會正好 相反。如第4圖所示，Va與Vb分別表示電壓轉換器22a、 22b施加於節點a、b之電壓，跨壓AV(亦即Va-Vb)則表示 施加於光源14之跨壓。理論上，為了使光源14兩端的跨 壓AV為最佳值，電壓轉換器22a、22b之開啟週期應該一 致，使得輸出於節點a、b之電壓Va、Vb之相位相差恰好 為180度。但是實際上，由於Va、Vb係由獨立之電壓轉 換器22a、22b之二次侧所提供，每個電壓轉換器在製造的 過程中，會因為不同電壓轉換器之間的鐵心接合面密合程 度、繞線鬆緊條件及組裝工藝不一致等因素影響，即使電 壓轉換器22a、22b之一次侧開啟週期一致的情形下，二次 侧輸出的電壓相位仍舊難以正好相差180度。如第4圖所 示，實際上，Va與Vb的相位會有誤差，這也就導致AV 1260454 的波形失真而無法提供最佳的協調電壓波形供應給光源。 【發明内容】 因此本發明之主要目的係提供一種可穩定發光之背 光模組，使得施加於光源的跨壓係一協調電壓波形，以解 決上述問題。 根據本發明之申請專利範圍，係提供一種可穩定發光 之背光驅動模組，其包含一電壓轉換器、一 DC/AC電源電 源、以及一光源。該電壓轉換器包含——次侧以及複數個 由該一次側感應之二次側。該電DC/AC電源係電連接於該 電壓轉換器之一次側，用來對該電壓轉換器之一次侧供 電。該光源係連接於該複數個二次側，用來依據該複數個 二次側輸出之電壓而發出光線。利用該電壓轉換器輸出至 該複數個二次側的電壓激發點亮該光源而發出光線。 本發明之優點在於，在同一個電壓轉換器中，將由同 ——次侧所感應之複數個二次侧所輸出電壓施加於背光模 組之光源，由於該複數個二次侧係由同--次側所感應， 故不會產生二次侧輸出之電壓相位有差異的問題，進一步 使得施加於該光源之跨壓係為最佳化結果。 1260454 為了使貴審查委員能更近一步了解本發明之特徵及 技術内容，請參閱以下有關本發明之詳細說明與附圖。然 而所附圖式僅供參考與輔助說明用，並非用來對本發明加 以限制者。 【實施方式】 請參考第5圖與第6圖，第5圖為一本發明應用於直下 式薄膜電晶體液晶顯示器之背光模組30之外觀示意圖，第 6圖為第5圖所示之背光模組30沿55’之剖面示意圖，其 中為清楚表達背光模組30内部之配置，故第5圖中未顯示 出擴散板等光學元件。如第5圖與第6圖所示，背光模組 30包含有一金屬背框(metal rear frame)62，作為背光模組 30之基座，一環狀結構之殼體(housing)64，垂直地欲固於 金屬背框62之四側邊，以形成一容納空間，複數個光源 (light source)32，容置於金屬背框62與殼體64所形成之容 納空間内，用以產生背光模組30所需之光源、一反射底板 68設於金屬背框62之表面，用以反射光源32向下方發射 出之光源以增加光的使用率，一擴散板70，覆蓋於殼體64 之侧邊使上述容納空間形成一近似密閉之空間，並將光源 32產生之光線散射至上方之液晶顯示面板（圖未示）以提供 1260454 均句刀政之光線’以及複數片反射片72，分別以傾斜方式 甘人口於'又體64輿金屬背框62之邊緣位置，肖以將光源32 沿水平方向發射之光線反射至擴散板70。反射底板68以 及反射片72通常係由高反射率材質構成，例如金屬或合 金，：或：利用表面具有高反射材質之高分子材質所組 $ i屬Θ框62係由鍍鋅鋼板、不銹鋼板、IS金屬板或紹 土板等材Μ構成’以提供足夠的結構強度與良好的熱傳 m2係由複數條平行設置於背光模組内之 直線型冷陰極h燈管所構成，亦可《要❹υ型冷陰 極螢光k官、外部電極螢光燈管、氤氣燈管以及平面燈管 等，以提供液晶I員示面板足夠之光源需求。 月i閱第7圖，第7圖係本發明之第一實施例之背光 权組30之光源、DC/AC冑源與電壓轉換器之連接示意圖。 由於刚述之光源32 -般係由交流電壓所驅動，故背光模組 扣另包含一電壓轉換器40以及一 DC/AC電源34。在本實 施例中，每一光源32係由同一電壓轉換器40所驅動，且 電壓轉換器係由DC/AC電源34供電至一次側，而由二次 側SI、S2輸出一交流電壓。電壓轉換器4〇之一次側ρι 系黾連接於DC/AC電源34，而二次側s 1、S2則分別電連 接於光源32之兩端。當DC/AC電源34對一次側P1 (亟數 1260454This will not only cause power loss, but also the brightness of the light emitted from both ends of the light source 14 will be uneven. In order to avoid this problem, please refer to FIG. 3 and FIG. 4, FIG. 3 is a schematic diagram of the light source 14 and the voltage converters 22a, 22b, and FIG. 4 is a voltage applied to the nodes a, b and applied to the light source 14 Voltage voltage diagram. The two ends of the light source 14 are electrically connected to the two voltage converters 22a, 22b, respectively, and the two independent voltage converters 22a, 22b are respectively connected to different power sources 26a, 26b. In general, the two ends of the light source 14 are connected to the secondary sides of the voltage converters 22a, 22b, respectively, and the polarities of the secondary sides of the voltage converters 22a, 22b are exactly opposite. As shown in Fig. 4, Va and Vb indicate the voltages applied to the nodes a and b by the voltage converters 22a and 22b, respectively, and the voltage across the voltage AV (i.e., Va-Vb) indicates the voltage applied to the light source 14. Theoretically, in order to make the voltage across the light source AV at the optimum value of the light source 14, the turn-on periods of the voltage converters 22a, 22b should be the same, so that the phases of the voltages Va, Vb outputted to the nodes a, b differ by exactly 180 degrees. However, in practice, since Va and Vb are provided by the secondary sides of the independent voltage converters 22a, 22b, each voltage converter is tightly bonded during the manufacturing process due to the core joint between the different voltage converters. The degree, the winding tightness condition, and the inconsistent assembly process affect the voltage phase of the secondary side output to be exactly 180 degrees apart even if the primary side opening periods of the voltage converters 22a, 22b are the same. As shown in Figure 4, in fact, there is an error in the phase of Va and Vb, which causes the waveform of the AV 1260454 to be distorted to provide an optimum coordinated voltage waveform to the source. SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide a backlight module that can stably illuminate such that a voltage waveform applied across the source of the light source is coordinated to solve the above problems. According to the patent application scope of the present invention, a backlight driving module capable of stably emitting light includes a voltage converter, a DC/AC power source, and a light source. The voltage converter includes a secondary side and a plurality of secondary sides sensed by the primary side. The electrical DC/AC power source is electrically coupled to the primary side of the voltage converter for supplying power to the primary side of the voltage converter. The light source is coupled to the plurality of secondary sides for emitting light in response to the voltage of the plurality of secondary side outputs. The voltage outputted to the plurality of secondary sides by the voltage converter excites the light source to emit light. The invention has the advantages that in the same voltage converter, the output voltages of the plurality of secondary sides induced by the same-minor side are applied to the light source of the backlight module, since the plurality of secondary side systems are the same - Since the secondary side senses, there is no problem that the voltage phase of the secondary side output differs, and the voltage across the light source is further optimized. 1260454 For a more detailed understanding of the features and technical aspects of the present invention, the following detailed description of the invention and the accompanying drawings. The drawings are for illustrative purposes only and are not intended to limit the invention. [Embodiment] Please refer to FIG. 5 and FIG. 6 , FIG. 5 is a schematic diagram of the appearance of a backlight module 30 applied to a direct-type thin film transistor liquid crystal display, and FIG. 6 is a backlight shown in FIG. The schematic diagram of the module 30 along the 55', in order to clearly express the internal configuration of the backlight module 30, does not show optical elements such as a diffuser in FIG. As shown in FIG. 5 and FIG. 6, the backlight module 30 includes a metal rear frame 62 as a base of the backlight module 30, a housing 64 of a ring structure, vertically To be fixed to the four sides of the metal back frame 62 to form a receiving space, a plurality of light sources 32 are received in the receiving space formed by the metal back frame 62 and the housing 64 to generate a backlight module. The light source required for the group 30 and a reflective bottom plate 68 are disposed on the surface of the metal back frame 62 for reflecting the light source emitted downward from the light source 32 to increase the light usage rate. A diffusion plate 70 covers the side of the housing 64. The accommodating space is formed into an approximately confined space, and the light generated by the light source 32 is scattered to the upper liquid crystal display panel (not shown) to provide 1260454 uniform ray light and a plurality of reflective sheets 72, respectively, inclined The method is in the position of the edge of the 64-inch metal back frame 62, and the light emitted from the light source 32 in the horizontal direction is reflected to the diffusion plate 70. The reflective bottom plate 68 and the reflective sheet 72 are usually made of a high reflectivity material, such as a metal or an alloy, or: a polymer material having a highly reflective material on the surface. The group is made of a galvanized steel sheet or a stainless steel sheet. , IS metal plate or sand plate and other materials constitute 'to provide sufficient structural strength and good heat transfer m2 is composed of a plurality of linear cold cathode h lamps arranged in parallel in the backlight module, or It is required to provide a cold cathode fluorescent lamp, an external electrode fluorescent tube, a xenon tube, and a flat tube to provide sufficient light source requirements for the liquid crystal panel. Referring to Figure 7, Figure 7 is a schematic diagram showing the connection of a light source, a DC/AC source and a voltage converter of the backlight unit 30 of the first embodiment of the present invention. Since the light source 32 just described is generally driven by an alternating voltage, the backlight module buckle further includes a voltage converter 40 and a DC/AC power source 34. In the present embodiment, each of the light sources 32 is driven by the same voltage converter 40, and the voltage converter is supplied from the DC/AC power source 34 to the primary side, and the secondary side SI, S2 outputs an alternating voltage. The primary side of the voltage converter 4 is connected to the DC/AC power source 34, and the secondary sides s1, S2 are electrically connected to both ends of the light source 32, respectively. When DC/AC power supply 34 is on the primary side P1 (number of turns 1260454
Nl)充電至電壓V時，二次侧SI、S2(匝數N2)的感應電壓 Vsl、Vs2皆為(N2/N1)*V。而感應電壓Vsl、Vs2則會施 加於光源32之兩端之節點c、d。 請參閱第8圖，第8圖係顯示施加於節點c、d的電壓 和施加於光源32之跨壓VL之關係圖。由於二次侧S1、S2 係感應自同--次侧P1，所以二次侧SI、s2的感應電壓When Nl) is charged to the voltage V, the induced voltages Vsl and Vs2 of the secondary side SI and S2 (number of turns N2) are (N2/N1)*V. The induced voltages Vs1 and Vs2 are applied to the nodes c and d at both ends of the light source 32. Referring to Fig. 8, Fig. 8 is a graph showing the relationship between the voltage applied to the nodes c, d and the voltage across the VL applied to the light source 32. Since the secondary side S1 and S2 are induced from the same-sub-side P1, the induced voltage of the secondary side SI and s2
Vs 1、Vs2的相位會一致，而不會出現相位差異的問題。由 於二次侧SI、S2接於節點C、D之極性正好相反，故二次 側SI、S2輸出電壓且施加於節點c、d的電壓相位會正好 相差180度，如第8圖所示。施加於光源32之跨壓VL為 Vc_Vd，而且感應電壓Vsl、Vs2並沒有相位落後的問題發 生，所以之波峰值正好為Vsl與Vs2之波峰值的兩倍（亦 即。在這樣的情形下，光源34所施加電壓Vl 既解決亮度不均的問題，同時也解決了功率耗損的缺失。 請參閱第9圖，第9圖係本發明之第二實施例之背光 模組50之光源、DC/AC電源與電壓轉換器之連接示意圖。 與第7圖之背光模組30不同之處在於，背光模組50之電 壓轉換器72具有由第一侧P1所感應之二次侧S1、S2、S3、 S4，其中二次侧S1、S3係串聯，而二次側S2、S4係串聯， 1260454 且二次侧SI、S3與二次侧S2、S4之極性相反，故施加於 光源32之跨壓VL也會產生第8圖之VL所示之效果。 請參閱第10圖，第10圖係本發明之第三實施例之背光 模組80之光源、DC/AC電源與電壓轉換器之連接示意圖。 背光模組80包含二個光源32a、32b，一 DC/AC電源34 以及電壓轉換器82。電壓轉換器52包含兩個一次侧P1、 P2以及複數個二次j則SI、S2、S3、S4，一次j則PI、P2 >[系 為串聯。二次側SI、S2係由一次侧P1所感應，二次側S3、 S4係由一次側P2所感應。DC/AC電源34係連結於串聯之 一次側PI、P2，而二次側SI、S2係連接於光源32a，二次 側S3、S4係連接於光源32b。由於一次侧PI、P2係串聯， 故可等效為一次側P12。由於一次側P12係由DC/AC電源 34所供電，所以二次側SI、S2、S3、S4所感應的電壓也 會具有相同之相位。背光模組80的二次侧SI、S2的極性 相反，而二次側S3、S4的極性亦相反，所以施加於光源 32a、32b之跨壓Vli、Vl2也會產生類似於第8圖之Vl所 示之效果。 請參閱第11圖，第11圖係本發明之第四實施例之背 光模組90之光源、DC/AC電源與電壓轉換器之連接示意 12 1260454 圖。與弟1G圖之f光模組8G不同之處在於，背光模組90 黾源34係連接於並聯之一次侧p 1、μ。而電壓 轉換口口 2的—次侧S1、S2的極性相反，而二次侧幻、％ 的極性亦相反，所以施加於光源32a、32b之跨壓Vu、Vl2 也會產生類似於第8圖之VL所示之效果。 本發明之應用也不限於兩個光源，多組光源亦可依據 本發明之機制與多個電壓轉換器加以連接。 請注意’本發明之背光模組雖以直下式（directtype) 背光模組為例作說明，但是光源位於顯示面板側邊附近的 側光式（edge light type)背光模組50亦可應用於本發明之概 念’請麥閱第12圖，第12圖係應用於側光式液晶顯示器 之背光模組之示意圖。侧光式背光模組110係設於一顯示 面板112的下方，主要包含有一導光板(light guide plate， LGP) 114設於顯示面板112下方、一光源（light source) 16 設於導光板114之一側、一反射罩118設於光源116之外 侧、一反射板(reflecting sheet)120設於導光板114下方並 固定於一框架122上，以及一擴散板(diffusing plate) 124設 於導光板114與顯示面板112之間。其中，光源116係用 來發出光線，反射罩118及反射板120係用於將光源116 13 1260454 所產生的光線反射至導光板114中以增加光的使用率，以 進而提供一較佳之亮度輸出。導光板114係用來將光源116 產生之該光源散射（scatter)至擴散板124，擴散板124可 將由導光板114反射出之光線進一步散射，以提供顯示面 板112較均勻分散之光線，而框架122則是用來固定導光 板114、光源116、反射罩118、反射板120及擴散板124。 侧光式背光模組110的光源、電壓轉換器以及DC/AC電源 的電連接方式和工作原理皆可與背光模組30、50、80、90 相同，在此不再贅述。 本發明之光源32係一氣體放電燈管（gas discharge lamp)，如冷陰極螢光燈管（cold cathode fluorescent lamp， CCFL)、外部電極螢光燈管(EEFL)氙氣燈管或是霓虹燈 管，或是任何以交流電驅動之燈管。而本發明之背光模組 30也可以應用於各種需要提供液晶顯示面板高亮度且均勻 之光源的液晶顯示器，如薄膜電晶體液晶顯示器（Thin-Film Transistor Liquid-Crystal Display，TFT-LCD)，矽液晶顯示器 (Liquid Crystal on Silicon display，LCoS display)等等。 綜上所述，相較於習知技術，本發明之背光模組的光源 係由極性相反之複數個二次侧所輸出之電壓所驅動，而且 14 1260454 該複數個二次侧係由同一次侧所感應，所以複數個二次侧 所輸出之電壓不會有相位誤差的產生，且避免漏電流及功 率損失。如此一來，本發明之背光模組之光源能產生更穩 定的光線。 以上所述僅為本發明之較佳實施例，凡依本發明申請 專利範圍所做之均等變化與修飾，皆應屬本發明之涵蓋範 圍。 【圖式簡單說明】 第1圖係習知背光模組之示意圖。 弟2圖係習知光源以*^父流電源所驅動之不意圖。 第3圖係光源與電壓轉換器之示意圖。 第4圖係施加於節點a、b之電壓以及施加於光源之跨壓之 電壓關係圖。 第5圖為一本發明應用於直下式薄膜電晶體液晶顯示器之 背光模組之外觀示意圖。 第6圖為第5圖所示之背光模組沿44’之剖面示意圖 第7圖係本發明之第一實施例之背光模組30之光源、 DC/AC電源與電壓轉換器之連接示意圖。 第8圖係顯示施加於節點c、d的電壓和施加於光源之跨壓 15 1260454 vL之關係圖。 第9圖係本發明之第二實施例之背光模組之光源、DC/AC 電源與電壓轉換器之連接示意圖。 第10圖係本發明之第三實施例之背光模組之光源、DC/AC ^ 電源與電壓轉換器之連接示意圖。 ^ 第11圖係本發明之第四實施例之背光模組之光源、DC/AC 電源與電壓轉換器之連接示意圖。 第12圖係應用於侧光式液晶顯示器之背光模組之示意圖。· 【主要元件符號說明】The phases of Vs 1 and Vs2 will be the same without the problem of phase difference. Since the polarity of the secondary side SI and S2 connected to the nodes C and D is reversed, the voltages of the secondary side SI and S2 output voltages and applied to the nodes c and d are exactly 180 degrees apart, as shown in Fig. 8. The cross-voltage VL applied to the light source 32 is Vc_Vd, and the induced voltages Vsl, Vs2 do not have a phase lag problem, so the peak value of the wave is exactly twice the peak value of Vsl and Vs2 (that is, in such a case, The voltage V1 applied by the light source 34 not only solves the problem of uneven brightness, but also solves the lack of power consumption. Referring to FIG. 9, FIG. 9 is a light source of the backlight module 50 of the second embodiment of the present invention, DC/ The connection between the AC power source and the voltage converter is different from the backlight module 30 of FIG. 7 in that the voltage converter 72 of the backlight module 50 has the secondary sides S1, S2, and S3 induced by the first side P1. , S4, wherein the secondary side S1, S3 are connected in series, and the secondary side S2, S4 are connected in series, 1260454 and the secondary side SI, S3 and the secondary side S2, S4 have opposite polarities, so the cross-pressure applied to the light source 32 VL also produces the effect shown by VL in Fig. 8. Referring to Fig. 10, Fig. 10 is a diagram showing the connection of a light source, a DC/AC power supply and a voltage converter of a backlight module 80 according to a third embodiment of the present invention. The backlight module 80 includes two light sources 32a, 32b, a DC/AC power source 34, and electricity. Voltage converter 82. Voltage converter 52 includes two primary sides P1, P2 and a plurality of secondary j, then SI, S2, S3, S4, and once j, PI, P2 > [system is connected in series. Secondary side SI, S2 is induced by the primary side P1, and secondary sides S3 and S4 are induced by the primary side P2. The DC/AC power supply 34 is connected to the primary side PI, P2 of the series, and the secondary side SI, S2 is connected to the light source. 32a, the secondary side S3, S4 is connected to the light source 32b. Since the primary side PI and P2 are connected in series, it can be equivalent to the primary side P12. Since the primary side P12 is powered by the DC/AC power source 34, the secondary side The voltages induced by SI, S2, S3, and S4 also have the same phase. The secondary sides SI, S2 of the backlight module 80 have opposite polarities, and the secondary sides S3 and S4 have opposite polarities, so they are applied to the light source 32a. The cross-over voltage Vli, Vl2 of 32b also produces an effect similar to that shown by V1 of Fig. 8. Referring to Fig. 11, FIG. 11 is a light source of the backlight module 90 of the fourth embodiment of the present invention, DC/ The connection between the AC power supply and the voltage converter is shown in Fig. 12 1260454. The difference from the optical module 8G of the 1G diagram is that the backlight module 90 is connected to the source 34. The primary side is p1, μ, and the polarity of the secondary side S1, S2 of the voltage conversion port 2 is opposite, and the polarity of the secondary side and % are opposite, so the voltage across the light sources 32a, 32b is Vu, Vl2 also produces an effect similar to that shown by VL of Figure 8. The application of the present invention is also not limited to two light sources, and multiple sets of light sources may be connected to a plurality of voltage converters in accordance with the mechanism of the present invention. Although the backlight module of the invention is described by taking a direct type backlight module as an example, an edge light type backlight module 50 having a light source located near the side of the display panel can also be applied to the concept of the present invention. Please refer to Figure 12, which is a schematic diagram of a backlight module applied to an edge-lit liquid crystal display. The side light type backlight module 110 is disposed under the display panel 112, and mainly includes a light guide plate (LGP) 114 disposed under the display panel 112, and a light source 16 disposed on the light guide plate 114. A reflective cover 118 is disposed on the outer side of the light source 116, a reflecting sheet 120 is disposed under the light guide plate 114 and fixed on a frame 122, and a diffusing plate 124 is disposed on the light guide plate 114. Between the display panel 112 and the display panel 112. The light source 116 is used to emit light, and the reflector 118 and the reflector 120 are used to reflect the light generated by the light source 116 13 1260454 into the light guide plate 114 to increase the light usage, thereby providing a better brightness output. . The light guide plate 114 is used to scatter the light source generated by the light source 116 to the diffuser plate 124. The diffuser plate 124 can further scatter the light reflected by the light guide plate 114 to provide a lighter uniform dispersion of the display panel 112. 122 is used to fix the light guide plate 114, the light source 116, the reflection cover 118, the reflection plate 120, and the diffusion plate 124. The light source, the voltage converter, and the DC/AC power supply of the edge-lit backlight module 110 can be the same as the backlight module 30, 50, 80, and 90, and will not be described herein. The light source 32 of the present invention is a gas discharge lamp, such as a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL) xenon lamp or a neon tube. Or any lamp that is driven by an alternating current. The backlight module 30 of the present invention can also be applied to various liquid crystal displays, such as a thin film LCD (Thin-Film Transistor Liquid-Crystal Display) Liquid crystal on Silicon display (LCoS display) and the like. In summary, compared with the prior art, the light source of the backlight module of the present invention is driven by a voltage outputted by a plurality of secondary sides of opposite polarities, and 14 1260454 is composed of the same secondary side by the same time. The side is sensed, so the voltage output from the plurality of secondary sides does not have a phase error, and leakage current and power loss are avoided. In this way, the light source of the backlight module of the present invention can generate more stable light. The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the invention are intended to be included in the scope of the present invention. [Simple description of the drawing] Fig. 1 is a schematic diagram of a conventional backlight module. Brother 2 is a schematic of the conventional light source driven by the *^ parent flow power supply. Figure 3 is a schematic diagram of a light source and voltage converter. Fig. 4 is a graph showing voltages applied to the voltages of the nodes a and b and the voltage across the light source. Fig. 5 is a schematic view showing the appearance of a backlight module applied to a direct type thin film transistor liquid crystal display. FIG. 6 is a cross-sectional view of the backlight module shown in FIG. 5 along the line 44'. FIG. 7 is a schematic diagram showing the connection of the light source, the DC/AC power source and the voltage converter of the backlight module 30 of the first embodiment of the present invention. Figure 8 is a graph showing the relationship between the voltage applied to nodes c, d and the voltage across the source 15 1260454 vL. FIG. 9 is a schematic diagram showing the connection of a light source, a DC/AC power source and a voltage converter of a backlight module according to a second embodiment of the present invention. Figure 10 is a schematic diagram showing the connection of a light source, a DC/AC^ power supply and a voltage converter of a backlight module according to a third embodiment of the present invention. ^11 is a schematic diagram showing the connection of a light source, a DC/AC power source and a voltage converter of a backlight module according to a fourth embodiment of the present invention. Figure 12 is a schematic diagram of a backlight module applied to an edge-lit liquid crystal display. · [Main component symbol description]
10 背光模組 12 液晶顯不面板 14 光源 16 擴散板 18 反射板 20 金屬殼體 22 電壓轉換器 26 DC/AC電源 22a、22b電壓轉換器 26a、26b DC/AC電源 30 背光模組 32 光源 32a、32b 光源 34 DC/AC電源 40 電壓轉換器 50 背光模組 52 電壓轉換器 62 金屬背框 64 殼體 68 反射底板 70 擴散板 72 反射片 16 1260454 80 背光模組 82 電壓轉換器 90 背光模組 92 電壓轉換器 110 背光模組 112 顯不面板 114 導光板 116 光源 118 反射罩 120 反射板 122 框架 124 擴散板 PI、P2 一次侧 S卜S2 二次侧 P12 等效之一次侧 a-d 節點 S3、S4 二次侧10 backlight module 12 LCD panel 14 light source 16 diffuser 18 reflector 20 metal housing 22 voltage converter 26 DC / AC power 22a, 22b voltage converter 26a, 26b DC / AC power supply 30 backlight module 32 light source 32a 32b light source 34 DC/AC power supply 40 voltage converter 50 backlight module 52 voltage converter 62 metal back frame 64 housing 68 reflective bottom plate 70 diffuser 72 reflective sheet 16 1260454 80 backlight module 82 voltage converter 90 backlight module 92 Voltage converter 110 Backlight module 112 Display panel 114 Light guide plate 116 Light source 118 Reflector 120 Reflector 122 Frame 124 Diffusion plate PI, P2 Primary side Sb S2 Secondary side P12 Equivalent primary side ad node S3, S4 Secondary side