201035607 六、發明說明： 【發明所屬之技術領域】 本發明是有關於一種導光結構及應用其之背光模組，且特別 是有關於一種在表面上具有微結構之導光結構及應用其之背光 模組。 【先前技術】 液晶顯示面板係利用背光模組來作為光源，以顯示影像。背 0 光模組係包括光源、導光板、反射片與光學膜。光源投射出的光 線係藉由導光板與反射片的導引來投射至光學膜中，以改善光學 表現。目前市面上背光模組中的光學膜大多以包括相互堆疊之兩 片增亮膜及一片擴散膜來調整光視角以提升輝度，並改善光的均 勻性。 然而’同時設置擴散片與增亮膜在背光模組中往往對應地增 加了背光模組的製造成本。因此，如何在減少背光模組的製造成 本的前提下，更同時有效地提升背光模組的光學表現，乃為相關 © 業者努力之課題之一。 【發明内容】 本發明係有關於一種導光結構及應用其之背光模組，其藉由 在上下兩表面上的微結構來集中光視角、提升光均勻性與光繞射 效率。 根據本發明，提出一種導光結構，包括一主體、一底部結構 及一頂部結構。主體具有一底面與一頂面。底面相對於頂面。底 部結構設置於底面上’且具有數個第一突出部。各第一突出部突 201035607 1 ννΗ-ΟΗΖΓΛ 出於底面，且各第一突出部的延伸方向實質上平行於一入射之第 一光線的一入射方向。第一突出部用以導引第一光線成為一朝向 頂面投射之第二光線。頂部結構設置於頂面上，且具有數個第二 突出部。各第二突出部突出於頂面，且各第二突出部的延伸方向 實質上垂直於各第一突出部的延伸方向。第二突出部用以利用繞 射原理導引第二光線。本發明之導光結構可設置於一背光模組 中，以對應地提升背光模組之光學表現。 為讓本發明之上述内容能更明顯易懂，下文特舉一較佳實施 例，並配合所附圖式，作詳細說明如下： 【實施方式】 請同時參照第1Α圖及第1Β圖，背光模組10對應一顯示面 板20之位置設置，以提供顯示面板20顯示用的光線。背光模組 10包括一光源組110、一反射片120、一導光結構130及一擴散 片 140。 反射片120、導光結構130及擴散片140係依序設置。光源 組110包括數個發光二極體，設置於導光結構130的一側。光源 組110用以投射出光線至導光結構130中。導光結構130係將射 入之光線往擴散片140的方向導引，以藉由擴散片140之表面結 構來均勻化通過其的光線。另外，背光模組10中可設置反射片 120來減少可能從導光結構130中漏出的光線，以提升光的利用 此處係以光源組110沿著一入射方向，也就是正X軸方向， 投射出一光線L1為例來作進一步的說明。導光結構130包括一 主體131、一底部結構132及一頂部結構133。主體131具有一 201035607 底面13 lb與一頂面13 It，且底面131b相對於頂面13 It。底部結 構132設置於底面131b上，且頂部結構133設置於頂面131t上。 如第1A圖所示，底部結構132具有數個突出於底面131b之第一 突出部pi。各第一突出部pi的延伸方向（X軸方向）實質上平 行於入射之光線L1的入射方向（正X軸方向）。如第1B圖所示， 頂部結構133具有數個突出於頂面131t之第二突出部p2。各第 二突出部p2的延伸方向（y軸方向）實質上垂直於各第一突出部 pi的延伸方向（X軸方向）。 0 第一突出部pi用以導引光線L1成為一朝向頂面投射之光線 L2,且第二突出部p2用以導引光線L2往擴散片140之方向投射， 以透過擴散片140來均勻化通過其之光線。 一般來說，光源組110之發光二極體為近似於朗伯 (lambertian)輻射型式之光源。若發光二極體所發出之光線射入頂 部結構133，且方位角未收斂時，頂部結構133的繞射效率往往 不佳。透過第一突出部pi的設置，發光二極體所發出之光線的 方位角可被收斂，以提升頂部結構133的繞射效率。 Q 此處以光線L1通過第2A及2B圖之第一突出部pi為例說 明。第2A及2B圖分別繪示光線投射至第一突出部的側視圖及俯 視圖。第一突出部pi的截面形狀為三角形，且位於頂邊P的頂 角為125°。假設光線L1投射到第一突出部pi的位置S處。光線 L1投射至第一突出部pi的方向與第一突出部pi的延伸方向的夾 角以角度φΐ標示。另外，請參照第3圖，其繪示朝向頂面13It 投射之光線L2的示意圖。為了清楚地表示出角度φ2與角度φ3， 第3圖中並未繪示出第1Α與1Β圖中之底部結構132,且主體131 係以虛線表示。如第3圖所示，光線L1經由第一突出部pi全反 5 201035607 射後的光線L2投影至底面131b與第一突出部pi的延伸方向（也 就是X軸方向）的夾角以角度φ2標示。再者，光線L2的投射方 向與頂面131t的法線方向Ν的夾角以角度φ3標示。 角度φ卜角度φ2與角度φ3的關係如下所述。當角度φΐ介 於-58°〜58°的入射光線L1藉由第一突出部pi來作全反射時，係 可形成角度φ2介於-41°〜41°且角度φ3介於47°〜90°的反射光線 L2。如此一來，反射光線L2的角度φ2係位在可提升頂部結構 133的繞射效率之範圍内。 之後，光線L2係投射至頂面結構133中。通過頂部結構133 的第二突出部ρ2之光線L2可藉由繞射原理來控制出光視角，並 同時改善色偏的情況。 以導光結構 132 之材料為聚甲基丙烯酸甲酯 (polymethylmethacrylate，ΡΜΜΑ)，且其折射率為 1.49 來舉例說明。 當投射至頂面之光線的角度φ2大於41度或小於-41度時係無法 產生繞射效應，而可能散射到他處或損耗掉。因此，藉由通過本 實施例之底部結構132，具有第二角度φ2大於41度或小於-41 度的光線係可調整至可產生繞射效應之角度範圍内，以收斂光線 的視角，且進一步提升光線的利用率與繞射效率。 如第1Α圖所示之各第一突出部pi為一體成形的長條狀結 構，然而，各第一突出部pi亦可由第4圖所示之數個子突出部 pll所組成，以藉由子突出部之數量與位置的配置來提高光的均 勻性。此外，各第一突出部pi的截面形狀除了可為圖中所示之 三角形外，亦可為弧形或多邊形。當第一突出部pi之截面形狀 為弧形時，第一突出部pi之立體形狀可為微鏡(micro lens)形、 雷射圓點（laser dot)或半圓形。當第一突出部pi之截面形狀為多 201035607 邊形時，第一突出部pi之立體形狀可為第5A或5B圖中之形狀。 只要是截面形狀的寬度從底面朝外逐漸減少，以收斂光線之方位 角的形狀，皆可作為第一突出部pi的形狀。各第一突出部pi亦 可依第6圖所示之各子突出部pl2依照平行於入射之光線L1的 入射方向排列所組成，其中各子突出部pl2之受光面的寬度從底 面131b朝外逐漸減少，且受光面朝向光源組110。也就是說，各 子突出部pl2係對應於光源組110的位置旋轉其設置位置，以藉 由子突出部pl2之位置的配置來提高光的均勻性。 0 另外，於本實施例中，頂部結構133以一個第二突出部p2 為一單位來組成一等週期性結構，且等週期性結構的形狀係為方 波。等週期性結構的週期的範圍為0.001〜1微米（μιη)，且各第二 突出部ρ2之高度的範圍為0.001〜1微米。較佳地，等週期性結構 之週期的範圍為0.1〜0.5微米，且各第二突出部ρ2之高度的範圍 為0,1〜0.5微米。當然，頂部結構133亦可以至少兩個第二突出 部ρ2為一單位來組成一等週期性結構，或者，頂部結構133可 為一不等週期結構。此外，週期性結構的形狀亦可為弦波、三角 〇 波、階梯波或鋸齒波。各個第二突出部ρ2的高度與形狀亦可彼 此相異，且可為一連續結構或一非連續結構，以進一步改善色偏 與控制通過其之光線L2的出光視角。 目前，市面上的背光模組大多包括兩片增亮膜及一擴散片， 造成通過其之光線損失，且總光通量（total flux )約略為0.49流 明（lm)。相較之下，讓具有同樣條件之光線通過背光模組10之 後的總光通量可達到2.407流明。因此，光線在通過具有兩片增 亮膜及一擴散片的背光模組的外部偶合效率較通過背光模組10 的外部偶合效率約低了 79%。換言之，背光模組10具有較高之 7 201035607 光利用率。 另外，第7圖繪示另一個背光模組10’之示意圖。與第IB 圖中之背光模組10相較，第7圖中之背光模組10’更包括一 1/2 波片151以及一 1/4波片152。1/2波片151與1/4波片152依序 設置於導光結構130之底面131b側。如此，光線因繞射而產生 色偏的情況係可減輕。 本發明上述實施例所揭露之導光結構及應用其之背光模 組，其以底部結構與頂部結構為實質上垂直的結構設計來集中光 線的視角，使得光線之均勻度與繞射效率可對應地提升。 综上所述，雖然本發明已以一較佳實施例揭露如上，然其並 非用以限定本發明。本發明所屬技術領域中具有通常知識者，在 不脫離本發明之精神和範圍内，當可作各種之更動與潤飾。因 此，本發明之保護範圍當視後附之申請專利範圍所界定者為準。 【圖式簡單說明】 第1A圖繪示根據本發明一較佳實施例之背光模組之爆炸 圖。 第1B圖繪示第1A圖中之背光模組的另一視角之爆炸圖。 第2A及2B圖分別繪示光線投射至第一突出部的側視圖及 俯視圖。 第3圖繪示朝向頂面投射之光線的示意圖。 第4圖繪示第一突出部包括數個子突出部之示意圖之一例。 第5A圖繪示第一突出部之立體示意圖之一例。 第5B圖繪示第一突出部之立體示意圖之另一例。 第6圖繪示第一突出部包括數個子突出部配置之俯視圖之 另一例。 8 201035607 第7圖繪示另一個背光模組之示意圖。 【主要元件符號說明】 10 :背光模組 20 :顯示面板 110 :光源組 120 :反射片 130 :導光結構 131 :主體 131b :底面 131t :頂面 132 :底部結構 133 :頂部結構 140 :擴散片 151 : 1/2 波片 152 : 1/4 波片 LI、L2 :光線 N:法線方向 P :頂邊 pi :第一突出部 pll、pl2 :子突出部 p2 :第二突出部 S :位置 φΐ、φ2、φ3 :角度201035607 VI. Description of the Invention: [Technical Field] The present invention relates to a light guiding structure and a backlight module using the same, and particularly to a light guiding structure having a microstructure on a surface and using the same Backlight module. [Prior Art] A liquid crystal display panel uses a backlight module as a light source to display an image. The back 0 optical module includes a light source, a light guide plate, a reflective sheet, and an optical film. The light projected from the light source is projected into the optical film by the guiding of the light guide plate and the reflective sheet to improve optical performance. At present, most of the optical films in the backlight module on the market include two brightness enhancing films and a diffusion film stacked on each other to adjust the viewing angle of the light to improve the brightness and improve the uniformity of the light. However, the simultaneous provision of the diffusion sheet and the brightness enhancement film in the backlight module tends to increase the manufacturing cost of the backlight module. Therefore, how to effectively improve the optical performance of the backlight module while reducing the manufacturing cost of the backlight module is one of the issues that the related companies are working hard. SUMMARY OF THE INVENTION The present invention relates to a light guiding structure and a backlight module using the same, which concentrates a light viewing angle, enhances light uniformity, and light diffraction efficiency by a microstructure on upper and lower surfaces. According to the present invention, a light directing structure is provided comprising a body, a bottom structure and a top structure. The body has a bottom surface and a top surface. The bottom surface is opposite to the top surface. The bottom structure is disposed on the bottom surface and has a plurality of first protrusions. Each of the first protruding protrusions 201035607 1 ννΗ-ΟΗΖΓΛ is from the bottom surface, and the extending direction of each of the first protruding portions is substantially parallel to an incident direction of the incident first light. The first protrusion is for guiding the first light to be a second light projected toward the top surface. The top structure is disposed on the top surface and has a plurality of second projections. Each of the second protrusions protrudes from the top surface, and the extending direction of each of the second protrusions is substantially perpendicular to the extending direction of each of the first protrusions. The second projection serves to guide the second light using the principle of diffraction. The light guiding structure of the present invention can be disposed in a backlight module to correspondingly enhance the optical performance of the backlight module. In order to make the above description of the present invention more comprehensible, the following description of the preferred embodiment and the accompanying drawings will be described in detail as follows: [Embodiment] Please refer to FIG. 1 and FIG. The module 10 is disposed corresponding to a position of the display panel 20 to provide light for display of the display panel 20. The backlight module 10 includes a light source group 110, a reflective sheet 120, a light guiding structure 130, and a diffusion sheet 140. The reflection sheet 120, the light guiding structure 130, and the diffusion sheet 140 are sequentially disposed. The light source group 110 includes a plurality of light emitting diodes disposed on one side of the light guiding structure 130. The light source group 110 is used to project light into the light guiding structure 130. The light guiding structure 130 guides the incident light toward the diffusion sheet 140 to homogenize the light passing therethrough by the surface structure of the diffusion sheet 140. In addition, the reflective module 120 can be disposed in the backlight module 10 to reduce the light that may leak from the light guiding structure 130, so as to enhance the utilization of the light, the light source group 110 is along an incident direction, that is, the positive X-axis direction. A light L1 is projected as an example for further explanation. The light guiding structure 130 includes a main body 131, a bottom structure 132 and a top structure 133. The main body 131 has a bottom surface 13 lb of 201035607 and a top surface 13 It, and the bottom surface 131b is opposite to the top surface 13 It. The bottom structure 132 is disposed on the bottom surface 131b, and the top structure 133 is disposed on the top surface 131t. As shown in Fig. 1A, the bottom structure 132 has a plurality of first projections pi protruding from the bottom surface 131b. The extending direction (X-axis direction) of each of the first protruding portions pi is substantially parallel to the incident direction (positive X-axis direction) of the incident light ray L1. As shown in FIG. 1B, the top structure 133 has a plurality of second protrusions p2 protruding from the top surface 131t. The extending direction (y-axis direction) of each of the second protruding portions p2 is substantially perpendicular to the extending direction (X-axis direction) of each of the first protruding portions pi. The first protrusion pi is used to guide the light L1 into a light L2 projected toward the top surface, and the second protrusion p2 is used to guide the light L2 to be projected in the direction of the diffusion sheet 140 to be uniformized by the diffusion sheet 140. Light through it. In general, the light emitting diode of source group 110 is a light source that approximates a lambertian radiation pattern. If the light emitted by the light-emitting diode is incident on the top structure 133 and the azimuth angle is not converged, the diffraction efficiency of the top structure 133 tends to be poor. Through the arrangement of the first protrusion pi, the azimuth of the light emitted by the light-emitting diode can be converged to enhance the diffraction efficiency of the top structure 133. Q Here, the light L1 passes through the first protrusion pi of the 2A and 2B drawings as an example. 2A and 2B are respectively a side view and a top view of light projected onto the first protrusion. The cross-sectional shape of the first protrusion pi is a triangle, and the apex angle at the top side P is 125°. It is assumed that the light ray L1 is projected to the position S of the first protrusion pi. The angle between the direction in which the light ray L1 is projected to the first protrusion pi and the direction in which the first protrusion pi extends is indicated by an angle φ 。 . In addition, please refer to FIG. 3, which shows a schematic view of the light L2 projected toward the top surface 13It. In order to clearly show the angle φ2 and the angle φ3, the bottom structure 132 in the first and second figures is not shown in Fig. 3, and the main body 131 is indicated by a broken line. As shown in FIG. 3, the angle L2 of the light ray L1 projected through the first protrusion pi all-inverted 5 201035607 to the extending direction of the bottom surface 131b and the first protrusion pi (that is, the X-axis direction) is indicated by the angle φ2. . Further, the angle between the projection direction of the light ray L2 and the normal direction Ν of the top surface 131t is indicated by an angle φ3. The relationship between the angle φb angle φ2 and the angle φ3 is as follows. When the incident light ray L1 having an angle φ ΐ between -58° and 58° is totally reflected by the first protruding portion pi, the angle φ2 is formed to be -41° to 41° and the angle φ3 is between 47° and 90°. ° Reflected light L2. As a result, the angle φ2 of the reflected ray L2 is in the range of the diffraction efficiency of the top structure 133. Light ray L2 is then projected into top surface structure 133. The light ray L2 passing through the second protrusion ρ2 of the top structure 133 can control the light viewing angle by the diffraction principle while improving the color shift. The material of the light guiding structure 132 is polymethylmethacrylate (polymethylmethacrylate), and its refractive index is 1.49. When the angle φ2 of the light projected to the top surface is larger than 41 degrees or smaller than -41 degrees, the diffraction effect cannot be generated, and it may be scattered elsewhere or lost. Therefore, by passing through the bottom structure 132 of the present embodiment, the light ray having the second angle φ2 greater than 41 degrees or less than -41 degrees can be adjusted to an angle range in which the diffraction effect can be generated to converge the angle of view of the light, and further Improve light utilization and diffraction efficiency. Each of the first protruding portions pi shown in FIG. 1 is an integrally formed elongated structure. However, each of the first protruding portions pi may be composed of a plurality of sub-protrusions p11 as shown in FIG. 4 to be protruded by sub-protrusions. The number and location of the sections are configured to increase the uniformity of light. Further, the cross-sectional shape of each of the first protrusions pi may be curved or polygonal in addition to the triangles shown in the drawing. When the cross-sectional shape of the first protrusion pi is curved, the three-dimensional shape of the first protrusion pi may be a micro lens shape, a laser dot or a semicircle. When the cross-sectional shape of the first protrusion pi is more than 201035607, the three-dimensional shape of the first protrusion pi may be the shape in the 5A or 5B. As long as the width of the cross-sectional shape gradually decreases from the bottom surface toward the outside, the shape of the azimuth angle of the condensed light can be used as the shape of the first protruding portion pi. Each of the first protrusions pi may also be arranged according to an incident direction parallel to the incident light L1 according to each sub-protrusion pl2 shown in FIG. 6, wherein the width of the light-receiving surface of each sub-protrusion pl2 is outward from the bottom surface 131b. Gradually decreasing, and the light receiving surface faces the light source group 110. That is, each of the sub-protrusions pl2 rotates its set position corresponding to the position of the light source group 110 to improve the uniformity of light by the arrangement of the positions of the sub-protrusions pl2. In addition, in the present embodiment, the top structure 133 is composed of a second protrusion p2 as a unit to form an equal periodic structure, and the shape of the isochronous structure is a square wave. The period of the periodic structure is in the range of 0.001 to 1 μm, and the height of each of the second protrusions ρ2 is in the range of 0.001 to 1 μm. Preferably, the period of the periodic structure is in the range of 0.1 to 0.5 μm, and the height of each of the second protrusions ρ2 is in the range of 0, 1 to 0.5 μm. Of course, the top structure 133 may also have at least two second protrusions ρ2 as a unit to form an equal periodic structure, or the top structure 133 may be an unequal periodic structure. In addition, the shape of the periodic structure may be a sine wave, a triangular wave, a staircase wave or a sawtooth wave. The height and shape of each of the second protrusions ρ2 may also be different from each other, and may be a continuous structure or a discontinuous structure to further improve the color shift and control the light-emitting angle of view of the light L2 passing therethrough. At present, most of the backlight modules on the market include two brightness enhancing films and a diffusing film, causing light loss through them, and the total luminous flux is about 0.49 lumens (lm). In contrast, the total luminous flux after passing the light of the same condition through the backlight module 10 can reach 2.407 lumens. Therefore, the external coupling efficiency of light passing through the backlight module having two brightening films and one diffusion sheet is about 79% lower than that of the external coupling through the backlight module 10. In other words, the backlight module 10 has a higher light utilization rate of 201035607. In addition, FIG. 7 is a schematic diagram of another backlight module 10'. Compared with the backlight module 10 in FIG. IB, the backlight module 10' in FIG. 7 further includes a 1/2 wave plate 151 and a 1/4 wave plate 152. The 1/2 wave plate 151 and 1/ The four wave plates 152 are sequentially disposed on the bottom surface 131b side of the light guiding structure 130. In this way, the color shift caused by the diffraction can be alleviated. The light guiding structure and the backlight module using the same according to the above embodiments of the present invention are designed to converge the viewing angle of the light with a structure in which the bottom structure and the top structure are substantially perpendicular, so that the uniformity of the light and the diffraction efficiency can be matched. Promote the ground. In view of the above, the present invention has been disclosed above in a preferred embodiment, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is an exploded view of a backlight module in accordance with a preferred embodiment of the present invention. FIG. 1B is an exploded view of another perspective view of the backlight module in FIG. 1A. 2A and 2B are respectively a side view and a plan view showing the light projected onto the first protrusion. Figure 3 is a schematic view of the light projected toward the top surface. FIG. 4 is a diagram showing an example of a schematic diagram in which the first protrusion includes a plurality of sub-protrusions. FIG. 5A is a schematic diagram showing an example of a perspective view of the first protruding portion. FIG. 5B illustrates another example of a perspective view of the first protrusion. Fig. 6 is a view showing another example of a plan view in which the first projection includes a plurality of sub-protrusions. 8 201035607 Figure 7 shows a schematic diagram of another backlight module. [Main component symbol description] 10: backlight module 20: display panel 110: light source group 120: reflective sheet 130: light guiding structure 131: main body 131b: bottom surface 131t: top surface 132: bottom structure 133: top structure 140: diffusion sheet 151 : 1/2 wave plate 152 : 1/4 wave plate LI, L2 : light N: normal direction P : top edge pi : first protruding portion p11, pl2 : sub-protrusion portion p2 : second protruding portion S : position Φΐ, φ2, φ3: angle