201109797 Fllbt)» 31787twf.doc/n 六、發明說明： 【發明所屬的技術領域】 本發明是有關於-種背光模組，且特別是有關於一種 能提供亮度與色度均勻之面光源的背光模組。 【先前技術】 傳統無導光板的背光模組是分別將光源、反射元件與 光學膜肢置於空動峻、底部與上方。辆所發出喊 束在無實際物體的空腔内傳遞反射。隨著光束反射數的增 加，整體混光特性就越佳，進而能夠達到亮度均勻的效果 然而，為提供免度均勻的面光源，空腔配置反射元件之一 端翹起的設計將使背光模組難以輕薄化。另一方面，藉由 改變反射元件與出光面的距離’以提升遠離光源處的光反 射率來改善出光能量不均勻的作法’也將使背光模組難以 薄型化。 另外’美國專利號7164863揭露一種背光模組，其包 括一光源、一光學腔、一稜鏡結構的材料片以及一具高反 射面的材料片。光源設置於光學腔旁，而稜鏡結構的材料 片與具高反射面的材料片分別配置於光學腔的上下兩表 面，其中兩材料片皆呈平板狀。另外，具高反射面的材料 片上提供結構圖案，並使用塗佈一散射反射材料（scattering reflective materials)，來控制光的反射。 除此之外，台灣專利公開號200636353揭露一種背光 模組’其包括一背板、一反光鏡、一反射層以及一透光板， 201109797 j-ίίθθδ； 3I787twf.doc/n 其中上述元件形成一封閉空間。而反射芦 散光結構適於使發光元件所發出的光束^勻穿透出 【發明内容】 本發明提出-種背光模組，其能提供 均勻的面光源。 …、頌邑201109797 Fllbt)» 31787twf.doc/n VI. Description of the Invention: [Technical Field] The present invention relates to a backlight module, and more particularly to a backlight capable of providing a surface light source having uniform brightness and chromaticity Module. [Prior Art] A conventional backlight module without a light guide plate separates a light source, a reflective element, and an optical film limb, respectively, at a space, a bottom, and a top. The shouting of the vehicle transmits reflections in the cavity without the actual object. As the number of reflections of the beam increases, the overall light mixing characteristic is better, and the brightness uniformity can be achieved. However, in order to provide a uniform surface light source, the design of one end of the cavity configuration reflective element will make the backlight module It is difficult to be thin and light. On the other hand, the method of improving the light energy non-uniformity by changing the distance between the reflective element and the light-emitting surface to increase the light reflectance away from the light source will also make the backlight module difficult to be thin. Further, U.S. Patent No. 7,164,863 discloses a backlight module comprising a light source, an optical cavity, a sheet of material of a meandering structure, and a sheet of material having a highly reflective surface. The light source is disposed beside the optical cavity, and the material piece of the 稜鏡 structure and the material piece with the high reflection surface are respectively disposed on the upper and lower surfaces of the optical cavity, wherein the two material pieces are flat. In addition, a material having a highly reflective surface is provided with a structural pattern on the sheet, and a scattering reflective material is applied to control the reflection of light. In addition, Taiwan Patent Publication No. 200636353 discloses a backlight module which includes a back plate, a mirror, a reflective layer and a light transmissive plate, 201109797 j-ίίθθδ; 3I787twf.doc/n wherein the above components form a Closed space. The reflective astigmatism structure is adapted to allow the light beam emitted by the illuminating element to be uniformly penetrated. SUMMARY OF THE INVENTION The present invention provides a backlight module capable of providing a uniform surface light source. ...,颂邑
本發明的其他目的和優點可倾本發明所揭露 術特徵中得到進一步的了解。 、技 為，上述之一或部份或全部目的或是其他目的，本 明之貝加例提供一種背光模組。此背光模組包括一可調 式反射偏振片（tunable reflective polarizer，TRP )、一透 ^ 基材、至少一發光元件、一反射元件以及多個光擴散微妹 構（optical diffusion microstructure)。透光基材配置於可 調式反射偏振片的一側，且具有一朝向可調式反射偏振片 的第一表面及一背對可調式反射偏振片的第二表面。除此 之外’透光基材與可調式反射偏振片保持一間隔空間，其 中間隔工間具有一入光截面。入光截面由透光基材的—端 延伸至與入光截面相鄰之可調式反射偏振片的一端。另 外’發光元件配置於間隔空間旁，且適於發出一光束。光 束適於經由入光截面進入間隔空間中，並適於經由穿透可 調式反射偏振片傳遞至背光模組外。反射元件配置於透光 基材的第二表面上。多個光擴散微結構設於透光基材，且 位於間隔空間與反射元件之間。 201109797 FH508 3l787twf.doc/n 在本發明之-實施例中’上述之光擴散微結構設 光基材之#近發光7〇件的部分。上述之光擴散微結構 ，發光元件處的數量密度例如大於在遠離發統件處 1孩度。上述之光擴散微結構可配置於透光基材的第一 面上。上述之光擴散微結構例如為一凸起或一凹陷。又 在本發明之一實施例中，上述之光擴散微結構的折射 率與透光基材的折射率相同。在本發明之一實施例中，上 述之光擴散微結構的折射率與透光基材的折射率不同。上 述之光擴散微結構可分布於透光基材内部，並位於第—李 面與第二表面之間。 、 在本發明之一實施例中，上述之反射元件為—反射鍍 膜。上述之可調式反射偏振片可具有朝向透光基材的 三表面。第一表面與第三表面可分別位於一第一參考平面 與—第二參考平面上，且發光元件可位於第一參考平面與 第二參考平面之間。 本發明之一 Μ施例另提出一種背光模組’包括一可調 式反射偏振片（tunable reflective polarizer, TRP )、一透光 基材、至少一發光元件、一反射元件以及一多層膜 (multilayer film)。透光基材配置於可調式反射偏振片的 —側’且具有一朝向可調式反射偏振；：}的第—表面及一背 對可調式反射偏振片的第二表面。除此之外，透光基材與 可调式反射偏振片保持一間隔空間，其中間隔空間具有一 入光截面。入光截面由透光基材的一端延伸至與其相鄰之 可調式反射偏振片的一端。另外，發光元件配置於間隔空 201109797 r i ιου8 31787twf.doc/n 間旁，且適於發出一光束。光束經由入光截面進入間隔空 間中，並經由穿透可調式反射偏振片傳遞至背光模組外。 反射元件配置於透光基材的第二表面上。多層膜配置於透 光基材的第一表面上。 在本發明之一實施例中’上述之多層膜配置於第一表 面之返離發光元件的一側。上述之多層膜可覆蓋至少部分 第一表面。 本發明之一實施例還提出一種背光模組，包括一可調 式反射偏振片（tunable reflective polarizer，TRP )、一透光 基材、至少一發光元件、一反射元件以及一繞射光學元件 層（diffractive optical elementlayer，DOE layer)。透光基Other objects and advantages of the invention will be apparent from the teachings of the invention. The present invention provides a backlight module in one or a part or all of the above or other purposes. The backlight module includes a tunable reflective polarizer (TRP), a transparent substrate, at least one illuminating element, a reflective element, and a plurality of optical diffusion microstructures. The light transmissive substrate is disposed on one side of the tunable reflective polarizer and has a first surface facing the tunable reflective polarizer and a second surface facing away from the tunable reflective polarizer. In addition to this, the light transmissive substrate and the adjustable reflective polarizer maintain a space in which the spacer has a light incident cross section. The light incident cross section extends from the end of the light transmissive substrate to one end of the adjustable reflective polarizer adjacent the light incident cross section. Further, the light-emitting element is disposed beside the space and is adapted to emit a light beam. The beam of light is adapted to enter the space through the light entering section and is adapted to be transmitted outside the backlight module via the penetrating tunable reflective polarizer. The reflective element is disposed on the second surface of the light transmissive substrate. A plurality of light diffusing microstructures are disposed on the light transmissive substrate and between the spacing space and the reflective element. 201109797 FH508 3l787twf.doc/n In the embodiment of the present invention, the portion of the above-mentioned light-diffusing microstructure-based light-emitting substrate is a near-light-emitting device. In the above light-diffusing microstructure, the number density at the light-emitting element is, for example, greater than 1 degree away from the hairline. The light diffusing microstructure described above may be disposed on the first side of the light transmissive substrate. The light diffusing microstructure described above is, for example, a protrusion or a depression. In still another embodiment of the invention, the light diffusing microstructure has a refractive index which is the same as the refractive index of the light transmissive substrate. In one embodiment of the invention, the refractive index of the light diffusing microstructure is different from the refractive index of the light transmissive substrate. The light diffusing microstructure described above may be distributed inside the light transmissive substrate and located between the first surface and the second surface. In an embodiment of the invention, the reflective element is a reflective coating. The above-mentioned adjustable reflective polarizing plate may have three surfaces facing the light transmissive substrate. The first surface and the third surface may be respectively located on a first reference plane and a second reference plane, and the light emitting element may be located between the first reference plane and the second reference plane. Another embodiment of the present invention further provides a backlight module 'including a tunable reflective polarizer (TRP), a light transmissive substrate, at least one light emitting element, a reflective element, and a multilayer film (multilayer) Film). The light transmissive substrate is disposed on the side of the tunable reflective polarizer and has a first surface oriented toward the tunable reflective polarization; and a second surface facing away from the tunable reflective polarizer. In addition, the light transmissive substrate maintains a space with the adjustable reflective polarizer, wherein the space has a light incident cross section. The light incident section extends from one end of the light transmissive substrate to one end of the adjustable reflective polarizer adjacent thereto. In addition, the light-emitting elements are disposed beside the space between 201109797 r i ιου8 31787twf.doc/n and are adapted to emit a light beam. The light beam enters the space through the light entering section and is transmitted outside the backlight module via the through-transmissive reflective polarizer. The reflective element is disposed on the second surface of the light transmissive substrate. The multilayer film is disposed on the first surface of the light transmissive substrate. In an embodiment of the invention, the multilayer film described above is disposed on a side of the first surface that is returned to the light-emitting element. The multilayer film described above may cover at least a portion of the first surface. An embodiment of the present invention further provides a backlight module including a tunable reflective polarizer (TRP), a light transmissive substrate, at least one light emitting component, a reflective component, and a diffractive optical component layer ( Diffractive optical elementlayer, DOE layer). Light-transmitting base
材配置於可凋式反射偏振片的一侧，且具有一朝向可調式 反射偏振片的第-表面及—背對可調式反射偏振片的第二 表面。除此之外，透光基材與可調式反射偏振片保持一間 隔空間’其中間隔空間具有—人域面。人域面由透光 基材的-端延伸至與人光截面相鄰之可調式反射偏振片的 二端。另外，發光元件配置於間隔空間旁，且適於發出一 光束。光束適於經由入光截面進入間隔空間中，並適於經 由穿透可調式反射偏振#傳輕背絲組外。反射元件配 置於透光基材的第二表面上。繞射光學元件層配置於透光 基材的第一表面上。 在-實關巾，上述之繞㈣學元件層配置 ^弟^蚊遠離發光元件的—側。上狀繞射光學元件 層可覆盍至少部份第一表面。 201109797 FllbbS 31787twf.doc/n 基於上述，在本發明之上述實施例的背光模組中，由 於透光基材的第一表面配置有反射元件，且透光基材的第 二表面配置有光學擴散結構、多層膜層或繞射光學元件 層，故可調整出光源的強度與色彩，以提供亮度與顏色均 勻的面光源。 為讓本發明之上述特徵和優點能更明顯易懂，下文特 舉多個實施例，並配合所附圖式，作詳細說明如下。 【實施方式】 有關本發明之前述及其他技術内容、特點與功效，在 以下配合參考圖式之多個實施例的詳細說明中，將可清楚 的呈現。以下實施例中所提到的方向用語，例如「上」、 「下」、「前」、「後」、「左」、「右」等，僅是參考 附加圖式的方向。因此，使用的方向用語是用來說明，而 非用來限制本發明。 第一實施例 圖1A繪示為本發明之第一實施例背光模組1〇〇的示 意圖。請參照圖1A，背光模組100包括一可調式反射偏振 片（tunable reflective polarizer，TRP ) 110、一透光基材 120、 至少一發光元件130、一反射元件140以及多個光擴散微 結構（optical diffusion microstructure) 150。 發光元件130例如是冷陰極榮光燈（cold cathode fluorescent lamp，CCFL)或是發光二極體（light emitting 201109797 PT16b8 31787twf.doc/n diode，LED)，且發光元件i3〇適於發出一光束132 〇可調 式反射偏振片110例如為3M公司（Minnesota Mining and Manufacturing Company)製造的特殊膜層（tunable reflectiveThe material is disposed on one side of the deflectable reflective polarizer and has a first surface facing the adjustable reflective polarizer and a second surface facing away from the adjustable reflective polarizer. In addition to this, the light-transmitting substrate and the adjustable reflective polarizer maintain a space in which the space has a human face. The human domain extends from the end of the light transmissive substrate to the ends of the tunable reflective polarizer adjacent to the human light section. Further, the light emitting element is disposed beside the space and is adapted to emit a light beam. The beam is adapted to enter the space through the light entering section and is adapted to pass through the transmissively tunable reflective polarization. The reflective element is disposed on the second surface of the light transmissive substrate. The diffractive optical element layer is disposed on the first surface of the light transmissive substrate. In the - solid towel, the above-mentioned four (4) element layer configuration ^ brother mosquito away from the side of the light-emitting element. The upper diffractive optical element layer covers at least a portion of the first surface. In the backlight module of the above embodiment of the present invention, the first surface of the light-transmitting substrate is provided with a reflective element, and the second surface of the light-transmitting substrate is provided with optical diffusion. The structure, the multilayer film layer or the diffractive optical element layer can adjust the intensity and color of the light source to provide a surface light source with uniform brightness and color. The above described features and advantages of the invention will be apparent from the following description. The above and other technical contents, features, and advantages of the present invention will be apparent from the following detailed description of the embodiments of the invention. The directional terms mentioned in the following embodiments, such as "upper", "lower", "before", "after", "left", "right", etc., are only directions referring to the additional schema. Therefore, the directional terminology used is for the purpose of illustration and not limitation. First Embodiment Fig. 1A is a view showing a backlight module 1A according to a first embodiment of the present invention. Referring to FIG. 1A , the backlight module 100 includes a tunable reflective polarizer (TRP ) 110 , a light transmissive substrate 120 , at least one light emitting component 130 , a reflective component 140 , and a plurality of light diffusing microstructures ( Optical diffusion microstructure) 150. The light-emitting element 130 is, for example, a cold cathode fluorescent lamp (CCFL) or a light-emitting diode (light emitting 201109797 PT16b8 31787twf.doc/n diode, LED), and the light-emitting element i3 is adapted to emit a light beam 132 〇 The tunable reflective polarizer 110 is, for example, a tunable reflective manufactured by 3M Company (Minnesota Mining and Manufacturing Company).
polarizer，TRP)。可調式反射偏振片u〇能依據光束ι32 的入射角選擇讓光束132反射或穿透。舉例而言，當光束 132的入射角大於某特定角度時，光束會被可調式反射偏 振片110反射。相反地，當光束132的入射角小於此特定 角度時，光束132可穿透可調式反射偏振片11〇，且穿透 的光束132為線偏振光。另一方面，上述特定角度在可調 式反射偏振片110上的不同位置可具有不同的量值，以調 整光束132的出光均句度或亮度分佈。 請繼續參照圖1A’透光基材120配置於可調式反射偏 振片11〇的-側’且具有一朝向可調式反射偏振片ιι〇的 第-表面122及-背對可調式反射偏振片UQ的第二表面 I24。透光基材m例如為一軟性基材或是—薄膜。除此之 外’透光基材120與可調式反射偏振片11〇保持一間 間160,而間隔空間16〇具有一入光截面162。呈體而= 透=板m與可調式反射偏振片11G可、。 固定其位置，以使彼此之間可保持咖空間 入光截面162由透光基材120的—端 162相鄰之可調式反射偏振片11〇的一端。-入先截面 如圖1A所示，至少一發光 辦。光束咖由人域面162⑽:工間 並經由穿_狀射 201109797 PT1668 31787twf.doc/n 外。反射元件140配置於透光基材120的第二表面124上。 在本實施例中，反射元件140例如為一反射鏡膜，其中反 射鍍膜可以是鏡面反射片或具有部份擴散功能的反射片。 另外，本實施例之可調式反射偏振片11〇具有朝向透光基 材120的一第三表面112。第一表面122與第三表面112 可分別位於一第一參考平面P1與一第二參考平面上P2， 且發光元件130位於第一參考平面pi與第二參考平面p2 之間。 除此之外，多個光擴散微結構150設於透光基材12〇, 且位於間隔空間16〇與反射元件140之間，其中光擴散微 結構150的製作方式例如是採用壓印或塗佈方式。本實施 例之光擴散微結構150為一凸起（例如為凸點），而其折 射率可與透光基材12〇的折射率不同或相同。另外，於其 他實施例中，光擴散微结構150也可以是一凹陷（例如為 凹點）（未繪示）’其中光擴散微結構15〇的折射率與透 光基材120的折射率相同。 值知注意的是，光學微結構150可改變光束130的反 射?度:達到調整背光模组1〇〇局部亮度的功能，進而提 供党度均勻的面光源。詳細而言，發光元件請所發出的 ，束132會經由入光截面162進入間隔空間16〇，其中部 知的光束132在照射到第-表Φ 122的光擴散結構150會 被折射，=以從可調式反射偏振片110的第三表面112 ^出或在第二表面⑴與透光基材120的第二表面124間 °反射而。卩分光束132在經多次反射後，會照射到透 201109797 ΠΙ008 3l787twf.doc/n 光基材120第一表面122上的光擴散微結構150，其中光 擴散結構150會改變並擴散光束132的行進方向，而使光 束132從第三表面112射出。或者，光束132會被位於第 二表面124下方的反射元件140反射，而依序穿透透光基 材120的第一表面122與可調式反射偏振片ho的第三表 面112。如此一來’背光模組1〇〇便可在第三表面122上 形成一面光源。 為使背光模組提供亮度均勻的面光源，在本實施 例中’光擴散微結構150則是設於透光基材丨2〇之靠近發 光元件130的部分。此外，在其他實施例中，可在第一表 面122靠近發光元件130處配置較多的光擴散微結構 15〇。換言之，光擴散微結構150靠近發光元件130處的數 量密度大於在遠離發光元件130處的數量密度。再者，在 其他實施例中’光擴散微結構150也可以分佈在整個第一 表面122。 另一方面，如圖1A所示，本實施例之光擴散微結構 150與反射元件140是分別配置於透光基材12〇的第一表 面122和第二表面124。因此相較習知直接將光擴散微結 構150形成於反射元件140上，而須額外地對反射元件14〇 作加工的技術，本實施例之背光模組1〇〇在製作 便，進而可以減少製造成本。 ’ 圖1B為本發明之另一實施例之背光模組2〇〇的示意 圖。圖1A與圖1B相似，惟兩者主要差異之處在於：背光 模組200的光擴散微結構15〇 (例如是擴散粒子）'分布於 201109797 ΡΊ 1668 31787twf.doc/n 透光基材12G内部’並位於第一表面122與第二表面124 之間。另外，本實施例之光擴散微結構150的折射率與透 光基材120的折射率不同。除此之外，在本實施例中，光 擴散微結構150靠近發光元件130處的數量密度大於在遠 離發光元件130處的數量密度。再者，在其他實施例中， 光擴散微結構150也可以分佈在整個第一表面122。 在以下的實施例與圖式中’相同或相似的標號代表相 同或相似的元件，以簡化說明。 第二實施例 圖2繪示為本發明之第二實施例背光模組3〇〇的示意 圖。如圖2所示，背光模組300包括可調式反射偏振片 (tunabk reflective polarizer，TOP) 110、透光基材 120、 發光元件130、反射元件140以及一多層膜（muitiiayer f|im) 310。請同時參照圖2與圖ΙΑ，背光模組300與背光模組 100相似’兩者主要差異之處在於：背光模組3〇〇包括配 置於透光基材120的第一表面122上的多層膜310。 如圖2所示’多層膜310配置於第一表面ι22之遠離 發光多件的一侧並覆蓋部份第一表面122。然而，在其他 實施例中，多層膜310亦可以完全覆蓋第一表面122，或 配置於第一表面122上的其他位置。多層膜31〇是由多個 折射率相異的介電材料交互堆疊而成。主要是利用光干涉 現象，而使多層膜310對光波長有選擇性的穿透和反射， 進而調整背光模組300的色均勻度。舉例而言，在遠離發 12 201109797 ΠΙΟΟδ 31787twf.doc/n 光元件130處配置多層膜310 ’則對應該位置因可調式反 射偏振片110而產生的色度差異變可獲得改善。如此一 來，背光模組300便可提供色度均勻的面光源。 第三實施例 圖3繪示為本發明之第二實施例背光模組4〇〇的示意 圖。如圖3所示，.背光模組400包括可調式反射偏振片 (tunable reflective polarizer，TRP) 11〇、透光基材 120、 發光元件130、反射元件140以及一繞射光學元件層 (diffractive optical element layer，DOE layer ) 410。請同時 參照圖2與圖3，背光模組400與背光模組300相似，兩 者主要差異之處在於：背光模組400包括配置於透光基材 120的第一表面122上的繞射光學元件層41〇。 如圖2所示，繞射光學元件層41〇配置於第一表面122 之遠離發光元件的一側並覆蓋部份第一表面122。然而， 在其他實施例中，繞射光學元件層41〇亦可以完全覆蓋第 一表面122 ’或配置於第一表面上的其他位置。繞射 光學元件層410對光波長有選擇性的穿透和反射，進而調 整背光模組100的色均勻度。舉例而言，在遠離發光元件 130處配置繞射光學元件層41〇，則對應該位置因可調式反 射偏振片110而產生的色度差異變可獲得改善。如此〜 來，背光模組400便可提供色度均勻的面光源。 练上所述，本發明之實施例的背光模組主要是藉由 擴散微結赫反射元㈣，並搭配可調式反射偏振片來調 13 201109797 FI 1608 31787twf.doc/n 整光束位於不同位置的反射或穿透強度，進而提供亮度均 勻的面光源。另外，由於本實施例的光擴散微結構與反射 元件層是分別配置在透光基材上下兩表面，故在製作上較 習知方便。除此之外，藉由多層膜以及繞射光學元件層也 可使特殊的光波長穿透或反射，因此可以改善可調式反射 偏振片造成的色偏現象，進而提供色彩均勻的面光源。. 惟以上所述者，僅為本發明之較佳實施例而已，當不 能以此限定本發明實施之範圍，即大凡依本發明申請專利 範圍及發明說明内容所作之簡單的等效變化與修飾，皆仍 屬本發明專利涵蓋之範圍内。另外，本發明的任一實施例 或申請專利範圍不須達成本發明所揭露之全部目的或優點 ，特點。此外，摘要部分和標題僅是用來辅助專利文件搜 尋之用，並非用來限制本發明之權利範圍。 【圖式簡單說明】 圖1A繪示為本發明之第一實施例背光模組的示意 圖0 圖1B為本發明之另一實施例之背光模組的示意圖。 圖2綠示為本發明之第二實施例背光模組的示意圖。 圖3綠示為本發明之第二實施例背光模組4〇〇的示意 圖0 201109797 r 丄 31787twf.doc/n 【主要元件符號說明】 100、200、300、400 :背光模組 110 :可調式反射偏振片 112 :第三表面 120 :透光基材 122 :第一表面 124 :第二表面 130 :發光元件 • 132 :光束 140 :反射元件 150 :光擴散微結構 160 :間隔空間 162 :入光截面 P1 :第一參考平面 P2 :第二參考平面 310 :多層膜 • 410:繞射光學元件層 15Polarizer, TRP). The adjustable reflective polarizer u〇 is selected to reflect or penetrate the beam 132 depending on the angle of incidence of the beam ι32. For example, when the angle of incidence of the beam 132 is greater than a certain angle, the beam is reflected by the tunable reflective polarizer 110. Conversely, when the angle of incidence of the beam 132 is less than this particular angle, the beam 132 can penetrate the tunable reflective polarizer 11 〇 and the transmitted beam 132 is linearly polarized. Alternatively, the particular angles described above may have different magnitudes at different locations on the tunable reflective polarizer 110 to adjust the uniformity or brightness distribution of the beam 132. Referring to FIG. 1A, the transparent substrate 120 is disposed on the side of the adjustable reflective polarizer 11A and has a first surface 122 facing the adjustable reflective polarizer and a back-adjustable reflective polarizer UQ. The second surface I24. The light-transmitting substrate m is, for example, a soft substrate or a film. In addition, the light-transmitting substrate 120 and the adjustable reflective polarizer 11 are held at an interval 160, and the space 16 is provided with a light-in section 162. Formed and = transparent plate m and adjustable reflective polarizer 11G. The position is fixed so that the ink-receiving section 162 is adjacent to one end of the adjustable reflective polarizer 11 相邻 adjacent to the end 162 of the light-transmitting substrate 120. - First section as shown in Fig. 1A, at least one illumination is performed. The beam coffee is made by the human face 162 (10): the work room and through the wearing _ _ 201109797 PT1668 31787twf.doc / n outside. The reflective element 140 is disposed on the second surface 124 of the light transmissive substrate 120. In the present embodiment, the reflective member 140 is, for example, a mirror film, wherein the reflective coating may be a specular reflection sheet or a reflection sheet having a partial diffusion function. In addition, the adjustable reflective polarizer 11 of the present embodiment has a third surface 112 facing the light transmissive substrate 120. The first surface 122 and the third surface 112 are respectively located on a first reference plane P1 and a second reference plane P2, and the light emitting element 130 is located between the first reference plane pi and the second reference plane p2. In addition, a plurality of light-diffusing microstructures 150 are disposed on the light-transmitting substrate 12A and located between the space 16〇 and the reflective element 140, wherein the light-diffusing microstructures 150 are fabricated, for example, by stamping or coating. Cloth way. The light-diffusing microstructure 150 of the present embodiment is a protrusion (e.g., a bump), and its refractive index may be different or the same as the refractive index of the light-transmitting substrate 12A. In addition, in other embodiments, the light-diffusing microstructure 150 may also be a recess (for example, a pit) (not shown). The refractive index of the light-diffusing microstructure 15 is the same as the refractive index of the transparent substrate 120. . It is to be noted that the optical microstructure 150 can change the reflection degree of the light beam 130: the function of adjusting the local brightness of the backlight module 1 to provide a uniform surface light source. In detail, the light emitting element is emitted, and the beam 132 enters the space 16 经由 via the light incident section 162, wherein the light beam 132 is refracted by the light diffusing structure 150 irradiated to the first table Φ 122. It is reflected from the third surface 112 of the tunable reflective polarizer 110 or between the second surface (1) and the second surface 124 of the transparent substrate 120. After being reflected multiple times, the split beam 132 will illuminate the light diffusing microstructure 150 on the first surface 122 of the light substrate 120 of 201109797 ΠΙ008 3l787twf.doc/n, wherein the light diffusing structure 150 will change and diffuse the light beam 132. The direction of travel is such that beam 132 is emitted from third surface 112. Alternatively, beam 132 is reflected by reflective element 140 located below second surface 124 and sequentially penetrates first surface 122 of light transmissive substrate 120 and third surface 112 of tunable reflective polarizer ho. In this way, the backlight module 1 can form a light source on the third surface 122. In order to provide the backlight module with a uniform surface light source of brightness, in the present embodiment, the light diffusing microstructure 150 is disposed on the portion of the light transmitting substrate 丨2 that is adjacent to the light emitting element 130. Moreover, in other embodiments, a plurality of light diffusing microstructures 15 can be disposed adjacent the light emitting elements 130 at the first surface 122. In other words, the number density of the light diffusing microstructures 150 near the light emitting elements 130 is greater than the number density at the distance from the light emitting elements 130. Further, in other embodiments, the light diffusing microstructures 150 may also be distributed throughout the first surface 122. On the other hand, as shown in Fig. 1A, the light-diffusing microstructures 150 and the reflective elements 140 of the present embodiment are disposed on the first surface 122 and the second surface 124 of the light-transmitting substrate 12A, respectively. Therefore, in the prior art, the light-diffusing microstructure 150 is directly formed on the reflective element 140, and the reflective element 14 must be additionally processed. The backlight module 1 of the present embodiment is fabricated, thereby reducing manufacturing cost. 1B is a schematic view of a backlight module 2A according to another embodiment of the present invention. 1A is similar to FIG. 1B, but the main difference between the two is that the light diffusion microstructure 15 〇 (for example, diffusion particles) of the backlight module 200 is distributed at 201109797 ΡΊ 1668 31787 twf.doc/n inside the transparent substrate 12G 'And between the first surface 122 and the second surface 124. Further, the refractive index of the light-diffusing microstructure 150 of the present embodiment is different from the refractive index of the light-transmitting substrate 120. In addition to this, in the present embodiment, the number density of the light-diffusing microstructures 150 near the light-emitting elements 130 is greater than the number density at the remote light-emitting elements 130. Moreover, in other embodiments, the light diffusing microstructures 150 may also be distributed throughout the first surface 122. The same or similar reference numerals are used to denote the same or similar elements in the following embodiments in the drawings to simplify the description. Second Embodiment FIG. 2 is a schematic view showing a backlight module 3A according to a second embodiment of the present invention. As shown in FIG. 2, the backlight module 300 includes a tunable reflective polarizer (TOP) 110, a light-transmitting substrate 120, a light-emitting element 130, a reflective element 140, and a multilayer film (muitiiayer f|im) 310. . Referring to FIG. 2 and FIG. 2 simultaneously, the backlight module 300 is similar to the backlight module 100. The main difference between the two is that the backlight module 3 includes multiple layers disposed on the first surface 122 of the transparent substrate 120. Film 310. As shown in Fig. 2, the multilayer film 310 is disposed on a side of the first surface ι22 away from the plurality of light-emitting pieces and covers a portion of the first surface 122. However, in other embodiments, the multilayer film 310 may also completely cover the first surface 122 or be disposed at other locations on the first surface 122. The multilayer film 31 is formed by alternately stacking a plurality of dielectric materials having different refractive indices. The light interference phenomenon is mainly used to selectively penetrate and reflect the wavelength of the light of the multilayer film 310, thereby adjusting the color uniformity of the backlight module 300. For example, arranging the multilayer film 310' at a distance away from the illuminating layer 31 201109797 ΠΙΟΟδ 31787 twf.doc/n optical element 130, the chromaticity difference corresponding to the position of the tunable reflective polarizing plate 110 can be improved. In this way, the backlight module 300 can provide a surface light source with uniform chromaticity. Third Embodiment FIG. 3 is a schematic view showing a backlight module 4A according to a second embodiment of the present invention. As shown in FIG. 3, the backlight module 400 includes a tunable reflective polarizer (TRP) 11 〇, a transparent substrate 120, a light-emitting element 130, a reflective element 140, and a diffractive optical layer. Element layer, DOE layer ) 410. Referring to FIG. 2 and FIG. 3 , the backlight module 400 is similar to the backlight module 300 . The main difference between the two is that the backlight module 400 includes diffractive optics disposed on the first surface 122 of the transparent substrate 120 . The element layer 41 is. As shown in FIG. 2, the diffractive optical element layer 41 is disposed on a side of the first surface 122 remote from the light emitting element and covers a portion of the first surface 122. However, in other embodiments, the diffractive optical element layer 41 can also completely cover the first surface 122' or other locations disposed on the first surface. The diffractive optical element layer 410 selectively penetrates and reflects the wavelength of the light to adjust the color uniformity of the backlight module 100. For example, by arranging the diffractive optical element layer 41 at a position away from the light-emitting element 130, the chromaticity difference corresponding to the position due to the tunable reflective polarizer 110 can be improved. Thus, the backlight module 400 can provide a surface light source with uniform chromaticity. As described above, the backlight module of the embodiment of the present invention is mainly adjusted by diffusing the micro-deformed reflection element (4) and adjusting the polarizing plate with the adjustable reflection lens. 2011 201109797 FI 1608 31787twf.doc/n The entire beam is located at different positions. Reflecting or penetrating the intensity, which in turn provides a uniform source of brightness. Further, since the light-diffusing microstructure and the reflective element layer of the present embodiment are disposed on the upper and lower surfaces of the light-transmitting substrate, respectively, it is convenient to manufacture. In addition, special light wavelengths can be penetrated or reflected by the multilayer film and the diffractive optical element layer, thereby improving the color shift caused by the adjustable reflective polarizer, thereby providing a uniform color source. The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention. All remain within the scope of the invention patent. In addition, any of the embodiments or advantages of the present invention are not required to achieve any of the objects or advantages and features of the present invention. In addition, the abstract sections and headings are only used to assist in the search for patent documents and are not intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a schematic view of a backlight module according to a first embodiment of the present invention. FIG. 1B is a schematic diagram of a backlight module according to another embodiment of the present invention. 2 is a schematic view showing a backlight module according to a second embodiment of the present invention. 3 is a schematic view of a backlight module 4A according to a second embodiment of the present invention. 201109797 r 丄31787twf.doc/n [Description of main components] 100, 200, 300, 400: backlight module 110: adjustable Reflecting polarizer 112: third surface 120: light transmissive substrate 122: first surface 124: second surface 130: light emitting element • 132: light beam 140: reflective element 150: light diffusing microstructure 160: spacing space 162: light entering Section P1: First Reference Plane P2: Second Reference Plane 310: Multilayer Film • 410: Diffractive Optical Element Layer 15