200841052 九、發明說明： 【發明所屬之技術領域】 本發明涉及-種光學器件及其製備 種偏光元件及其製備方法。 一汰 【先前技術】 2光讀係-㈣要之林器件，被廣泛應用於太陽 鏡與液晶顯示器中。找廣泛應用之—種偏光元件，可吸200841052 IX. Description of the Invention: [Technical Field] The present invention relates to an optical device and a preparation method thereof, and a method of fabricating the same. [Previous technology] 2 Optical reading system - (4) Essential forest devices are widely used in solar mirrors and liquid crystal displays. Looking for a wide range of applications - a polarizing element that can be sucked
個偏振態之光，㈣-偏振態之光則通過偏光元件。 此種偏光讀通常制這樣—種方法轉：將二向色性分 子溶于或吸收在高分子物質巾’如聚⑽醇，並將所得薄 膜以二個方向拉伸配列二向色性分子。這時，二向色性分 子沿著拉伸方向有規麟列起來，形成—條長鏈。在入射 光波中，光振動方向平行於長鏈方向之光被吸收，垂直於 長鏈方向之絲透過，所以透射光成树偏振光。此種偏 光凡件也可以通過將二向色性分子吸收在單軸拉伸之聚合 物膜上之方法來生產。 由於此種偏光元件之製造需要將二向色性分子結合高 分子聚合物作為偏光膜，製備過程較為複雜。而應用高分 子聚合物作為偏光膜之偏光元件於50°C以上使用一段時間 後，偏光膜之偏光率減少，甚至失去偏光作用。而且此類 偏光元件對濕度要求也較高，一旦工作環境惡劣，濕度大， 偏光元件將失去偏光作用。 另，先前之偏光元件一般只對某一波段之電磁波（如 微波、紅外光、可見光、紫外光等）具有良好之偏振性能， 7 200841052 無法對各種波長之電磁波麵—之偏振吸收特性。 有鑒於此，提供-種對各種波長之電磁波均 之偏振性能之偏光元件及絲備方法實為〜、有良好 【發明内容】 種偏光元件’其包括—支撐體與—由 樓之偏光膜，其中，該偏光膜包括至少-奈“2 膜’該偏光财奈米碳管均沿同—方向^向排=涛 该奈米碳管薄膜之層數大於等於10層。 該示米石反官薄膜之厚度為〇· 〇1〜100微米。 該奈米碳管薄膜為多個首尾相連之奈击 以擇優取向排_叙_滅。 “束The light of one polarization state, (4) - the light of the polarization state passes through the polarizing element. Such a polarized reading is usually produced by dissolving or absorbing a dichroic molecule in a polymeric material such as poly(10) alcohol, and stretching the resulting film in two directions to form a dichroic molecule. At this time, the dichroic molecules are arranged along the stretching direction to form a long chain. In the incident light wave, the light having the direction of the light vibration parallel to the long-chain direction is absorbed, and the light perpendicular to the long-chain direction is transmitted, so that the transmitted light is converted into a tree-polarized light. Such a polarizing member can also be produced by a method of absorbing a dichroic molecule on a uniaxially stretched polymer film. Since the manufacture of such a polarizing element requires the use of a dichroic molecule in combination with a high molecular polymer as a polarizing film, the preparation process is complicated. When a polarizing element using a high molecular polymer as a polarizing film is used at a temperature of 50 ° C or more for a period of time, the polarizing ratio of the polarizing film is reduced, and even the polarizing effect is lost. Moreover, such polarizing elements have high requirements on humidity. Once the working environment is bad and the humidity is high, the polarizing element will lose its polarizing effect. In addition, the prior polarizing elements generally have good polarization properties only for electromagnetic waves of a certain wavelength band (such as microwave, infrared light, visible light, ultraviolet light, etc.), and the polarization absorption characteristics of electromagnetic wave surfaces of various wavelengths are not available. In view of the above, it is possible to provide a polarizing element and a wire preparation method for polarizing performance of electromagnetic waves of various wavelengths, and it is good that the polarizing element includes a support film and a polarizing film of the floor. Wherein, the polarizing film comprises at least a neat "2 film", the polarized carbon nanotubes are all along the same direction, and the number of layers of the carbon nanotube film is greater than or equal to 10 layers. The thickness of the film is 〇· 〇1~100 μm. The carbon nanotube film is a plurality of end-to-end shots arranged in a preferred orientation.
該支撐體為固定框架或透明基板。 種偏光元件之製備方法，其包括以下步驟··提 t支樓體；提供至少—層奈米碳管薄膜，該奈米碳 中奈米碳管均沿同，方向排列；以及將上述奈 米石反官薄_附固定於上述支撐體形成偏光元件。 進步將多層奈米碳管薄膜沿相同方向重疊地 山》 支樓歧形成偏光元件，該偏光元件中奈米 碳官均沿同—方向排列。 上述奈米碳管薄膜之製備方法包括以下步驟：提 ^示米唉官陣列；從上述奈米碳管陣列中選定一定 、太/夕個奈米碳管束；以及以一定速度沿基本垂直 于不米蚊官陣列生長方向拉伸該多個奈米碳管束，以 形成-連續之奈米碳管薄媒。 200841052 上述奈米碳管陣列之製備方法包括以下步驟：提 ‘供一平整基底；在基底表面均勻形成一催化劑層；將 • 上述形成有催化劑層之基底在700〜900°C之空氣中退 火約30分鐘〜90分鐘；以及將處理過之基底置於反應 爐中，在保護氣體環境下加熱到500〜740°C，然後通 入碳源氣反應約5〜30分鐘，生長得到高度為200〜400 微米之奈米碳管陣列。 進一步包括用有機溶劑處理該偏光元件中之奈 ⑩ 米碳管薄膜。 上述使用有機溶劑處理奈米碳管薄膜之方法包 括通過試管將有機溶劑滴落在奈米碳管薄膜表面浸 潤整個奈米碳管薄膜，或將上述形成有奈米碟管薄膜 之支撐體整個浸入盛有有機溶劑之容器中浸潤。 上述有機溶劑為乙醇、曱醇、丙酮、二氯乙烷或 氯仿。 相較於先前技術，所述之偏光元件採用多層奈米 ^ 碳管薄膜作為偏振膜，由於奈米碳管具有高溫之熱穩 定性，對於各種波長之電磁波有均一之吸收特性，故 本發明之偏光元件對於各種波長之電磁波有均一之 偏振吸收性能，具有廣泛之應用範圍。 【實施方式】 以下將結合附圖對本發明作進一步之詳細說明。 請參閱圖1，本發明提供一種偏光元件10，該偏 光元件10包括一支撐體12與一由支撐體12支撐之 9 200841052 奈米碳管薄膜]4。該支撐體】 透明基板。該奈米碳管薄膜H直接細 或二 外框或透明基板表面作為偏光夺、疋框架 可為-層或堆疊之多層薄㈣二不未蚊官缚膜14 14為多個首尾相連之奈米碳管束以摆供：厌5㈣ ,^ , 束以擇優取向排列形 成之潯膜結構。當該奈米碳管薄膜Μ 奈求碳管薄膜14中奈米碳管束美…夕^，該 排列。 w束基本沿同-方向定向The support is a fixed frame or a transparent substrate. a method for preparing a polarizing element, comprising the steps of: providing a t-substrate; providing at least a layer of carbon nanotube film, wherein the carbon nanotubes are arranged along the same direction; and the above-mentioned nano The stone anti-official thin_ is attached to the above support to form a polarizing element. Progressively, the multilayered carbon nanotube film is overlapped in the same direction to form a polarizing element, and the nanocarbons of the polarizing element are arranged in the same direction. The method for preparing the above carbon nanotube film comprises the steps of: extracting a rice squash array; selecting a certain, too/seven carbon nanotube bundle from the carbon nanotube array; and substantially perpendicular to the The plurality of carbon nanotube bundles are stretched in the growth direction of the M. mosquito net array to form a continuous carbon nanotube thin medium. 200841052 The preparation method of the above carbon nanotube array comprises the steps of: providing a flat substrate; forming a catalyst layer uniformly on the surface of the substrate; and annealing the substrate on which the catalyst layer is formed in air at 700 to 900 ° C. 30 minutes to 90 minutes; and the treated substrate is placed in a reaction furnace, heated to 500-740 ° C under a protective gas atmosphere, and then reacted with carbon source gas for about 5 to 30 minutes, and the growth height is 200~ 400 micron carbon nanotube array. Further, the film of the carbon nanotubes in the polarizing element is treated with an organic solvent. The above method for treating a carbon nanotube film by using an organic solvent comprises: dipping an organic solvent onto a surface of a carbon nanotube film by a test tube to infiltrate the entire carbon nanotube film, or immersing the support body formed with the film of the nano-disc film; Infiltrated in a container containing an organic solvent. The above organic solvent is ethanol, decyl alcohol, acetone, dichloroethane or chloroform. Compared with the prior art, the polarizing element adopts a multi-layered carbon nanotube film as a polarizing film, and since the carbon nanotube has high temperature thermal stability, it has uniform absorption characteristics for electromagnetic waves of various wavelengths, so the present invention The polarizing element has uniform polarization absorption properties for electromagnetic waves of various wavelengths and has a wide range of applications. [Embodiment] Hereinafter, the present invention will be further described in detail with reference to the accompanying drawings. Referring to Fig. 1, the present invention provides a polarizing element 10 comprising a support 12 and a 9200841052 carbon nanotube film 4 supported by a support 12. The support is a transparent substrate. The carbon nanotube film H is directly thin or the outer frame or the surface of the transparent substrate is used as a polarizing light, and the frame can be a layer or a stacked layer of thin (four) two non-mosquito binding film 14 14 is a plurality of end-to-end nanometers. The carbon tube bundle is provided with a membranous structure formed by arranging 5 (four), ^, and bundles in a preferred orientation. When the carbon nanotube film is in the carbon nanotube film 14, the carbon nanotube bundle is beautiful... w beam is oriented substantially in the same direction
私η貝犯例T该奈米碳管薄膜14之寬产可為 ^10厘米，該奈米碳管薄膜14之厚度為G息Γ〇〇: 本發明實施例料元件1G之偏振吸收性能盘夺 ^炭管薄膜u之層數有關，奈米碳管薄膜14層數越 夕，该偏光兀件10之偏振性能越好。 由於奈米碳管對電磁波之吸收接近絕對黑體，奈The private carbon nanotube film 14 can have a wide yield of 10 cm, and the thickness of the carbon nanotube film 14 is G: 偏振: The polarization absorption performance plate of the material element 1G of the embodiment of the invention The number of layers of the carbon nanotube film u is related, and the number of layers of the carbon nanotube film 14 is higher, and the polarization performance of the polarizing element 10 is better. Because the absorption of electromagnetic waves by the carbon nanotubes is close to the absolute black body,
米碳管對於各種波長之電磁波均有均一之吸收S 性’故本發明之偏光元件1Q對於各種波長之電磁波 也有均一之偏振吸收性能。當光波入射時，振動方向 =行于奈米碳管束長度方向之光被吸收，垂直于奈: 石厌S束長度方向之光能透過，所卩透射光成為線偏振 光0 請參閱圖2，本發明實施例偏光元件10之製備方 法主要包括以下幾個步驟： 步驟一：提供一奈米碳管陣列，優選地，該陣列 為超順排奈米碳管陣列。 200841052 本實施例中，超順排奈求碳管陣列之製備方法採 用化學氣相沉積法，其具體步驟包括：（a)提供一平 整基底，該基底可選用P型或N型矽基底，或選用形 成有氧化層之矽基底，本實施例優選為採用4英寸之 矽基底；（b)在基底表面均勻形成一催化劑層，該催 化劑層材料可選用鐵（Fe)、鈷（Co)、鎳（Nl)或其 任意組合之合金之一；（C)將上述形成有催化劑層之 基底在700〜900°c之空氣中退火約30分鐘〜9〇分 U)將處理過之基底置於反職巾，在保護氣體環 境下加熱到500儀’然後通入碳源氣體反應約 5〜30分鐘，生長得到超順排奈米碳管陣列，其高度為 200〜400微米。該超順排奈米碳管陣列為多個彼此平 行且垂直於基底生長之奈米碳管形成之純奈米碳管 陣列。通過上述控制生長祕，該超順排奈米碳管陣 列中基本不含有雜質，如無定型碳或㈣.化劑全 屬顆粒等。該奈米碳管陣列中之奈米石炭管彼此通過凡 德瓦爾力緊密接觸形成陣列。 山t實施财碳執可制乙炔等化學性質較活潑 之石厌氫化合物，保護氣體可選 卜 體。 」^用鼠乳、氨氣或惰性氣 步驟^一 ·採用一拉仲工1 /从夫 獲得至少-太米石…处示米碳管陣列中拉取 ^ . 不…、反&潯臊。該奈米碳管薄膜之f備呈 從上述奈米碳管陣二 疋見度之夕個奈米碳管片斷’本實施例優選為採用具 200841052 有一定寬度之膠帶接觸奈米碳管陣列以選定一定寬 * 度之多個奈米碳管束；（b)以一定速度沿基本垂直于 w 奈米碳管陣列生長方向拉伸多個該奈米碳管束，以形 成一連續之奈米碳管薄膜。 在上述拉伸過程中，該多個奈米碳管束在拉力作 用下沿拉伸方向逐漸脫離基底之同時，由於范德華力 作用，該選定之多個奈米碳管束分別與其他奈米碳管 束首尾相連地連續地被拉出，從而形成一奈米碳管薄 • 膜。該奈米碳管薄膜為擇優取向排列之多個奈米碳管 束首尾相連形成之具有一定寬度之奈米碳管薄膜。該 奈米碳管薄膜中奈米碳管之排列方向基本平行于奈 米碳管薄膜之拉伸方向。 本實施例中，該奈米碳管薄膜之寬度與奈米碳管 陣列所生長之基底之尺寸有關，該奈米碳管薄膜之長 度不限，可根據實際需求制得。本實施例中採用4英 I 寸之基底生長超順排奈米碳管陣列，該奈米碳管薄膜 之寬度可為1〜10厘米，該奈米碳管薄膜之厚度為 0. 01〜100微米。 步驟三··提供一支撐體，將上述奈米碳管薄膜沿 預定方向粘附固定於支撐體，從而得到偏光元件。 本實施例中，該支撐體可為一方形之金屬固定框 架，用於固定奈米碳管薄膜，其材質不限，固定框架 外之多餘之奈米碳管薄膜可直接去除。 由於本實施例步驟一中提供之超順排奈米碳管陣 12 200841052 列中之奈米碳管非常純淨，且由於奈米碳管本身之比 β 表面積非常大，所以該奈米碳管薄膜本身具有較強之 w 粘性。步驟三中該奈米碳管薄膜可利用其本身之粘性 直接粘附於固定框架，使該奈米碳管薄膜之四周通過 固定框架固定，該奈米碳管薄膜之中間部分懸空。 本實施例中’該支撐體也可為一透明基板。上述 第一奈米碳管薄膜可直接黏附於透明基板表面。 本技術領域技術人貝應明白’該支撐體之大小可 • 依據實際需求確定，當支撐體之寬度大於上述奈米碳 管薄膜之寬度時，可將多個上述奈米碳管薄膜無間隙 地並排覆蓋並粘附在支撐體上。 可以理解，步驟三中，可將多層奈米碳管薄膜沿 相同之方向粘附固定於上述支撐體得到偏光元件。 該多層奈米碳管薄膜之間由於范德華力緊密連接 形成穩定之多層奈米碳管薄膜結構。該奈米碳管薄膜 之層數不限，具體可依據實際需求製備。 0 另外，上述獲得之偏光元件可進一步使用有機溶 劑處理偏光元件中之奈米碳管薄膜。 可通過試管將有機溶劑滴落在奈米碳管薄膜表面 浸潤整個奈米碳管薄膜，或者，也可將上述形成有奈 米碳管薄膜之固定框架整個浸入盛有有機溶劑之容 器中浸潤。該有機溶劑為揮發性有機溶劑，如乙醇、 曱醇、丙酮、二氣乙烧或氯仿，本實施例中優選採用 乙醇。該奈米碳管薄膜經有機溶劑浸潤處理後，在揮 13 200841052 發性有機溶劑之表面張力之作用下，奈米碳管薄膜中 - 之平行之奈米碳管束會部分聚集，因此，處理後之該 * 奈米碳管薄膜表面體積比小，無粘性，且具有良好之 機械強度及韌性。處理後之偏光元件能更方便地應用 於宏觀領域。 請參閱圖3及圖4,為本發明實施例偏光元件使用 有機溶劑處理前後之掃描電子顯微鏡照片（SEM)對比 示意圖。偏光元件之奈米碳管薄膜中奈米碳管均定向 ⑩ 排列，相鄰奈米碳管薄膜之間通過范德華力結合。進 一步地，將上述獲得之偏光元件中之奈米碳管薄膜使 用有機溶劑處理後，在表面張力之作用下，處理後之 該奈米碳管薄膜中之奈米碳管聚集成束。處理後之該 奈米碳管薄膜表面體積比小，無粘性，且具有良好之 機械強度及韌性，因此能更方便地應用於宏觀領域。 請參閱圖5,本發明偏光元件分別採用2層、5層、 10層、20層與30層奈米碟管薄膜作為偏振膜，由於 奈米碳管對於各種波長之電磁波均有均一之吸收特 性’故本發明之偏光元件對於各種波長之電磁波也有 均一之偏振吸收性能。同時，從圖5中可明顯看出， 當奈米碳管薄膜層數較少時，該偏光元件在紫外波段 會有較好之偏振性能，當偏光元件中奈米碳管薄膜之 層數越多，偏光元件之偏振度越高，可在各個波段均 具有良好之偏振性能。 綜上所述，本發明確已符合發明專利之要件，遂 14 200841052 依法提出專利申請。惟，以上所述者僅為本發明之較 ‘佳實施例，自不能以此限制本案之申請專利範圍。舉 A 凡熟悉本案技藝之人士援依本發明之精神所作之等 效修飾或變化，皆應涵蓋於以下申請專利範圍内。 【圖式簡單說明】 圖1係本發明實施例偏光元件之結構示意圖。 圖2係本發明實施例偏光元件之製備方法之流程 圖。 • 圖3係本發明實施例有機溶劑處理前之偏光元件 之掃描電鏡照片。 圖4係本發明實施例有機溶劑處理後之偏光元件 之掃描電鏡照片。 圖5係本發明實施例採用不同層數之奈米碳管薄 膜之偏光元件在各波長下之偏振度對比示意圖。 【主要元件符號說明】 偏光元件 10 支撐體 12 _ 奈米碳管薄膜 14 15The carbon nanotubes have uniform absorption S properties for electromagnetic waves of various wavelengths. Therefore, the polarizing element 1Q of the present invention has uniform polarization absorption properties for electromagnetic waves of various wavelengths. When the light wave is incident, the direction of vibration = light traveling in the longitudinal direction of the carbon nanotube bundle is absorbed, perpendicular to the light energy of the length of the nano-S beam, and the transmitted light becomes linearly polarized light. See Figure 2, The preparation method of the polarizing element 10 of the embodiment of the invention mainly comprises the following steps: Step 1: providing an array of carbon nanotubes, preferably the array is a super-sequential carbon nanotube array. In the present embodiment, the method for preparing the super-shun carbon nanotube array adopts a chemical vapor deposition method, and the specific steps thereof include: (a) providing a flat substrate, the substrate may be selected from a P-type or N-type germanium substrate, or The crucible substrate formed with the oxide layer is selected, and in this embodiment, a 4-inch crucible substrate is preferably used; (b) a catalyst layer is uniformly formed on the surface of the substrate, and the catalyst layer material may be selected from iron (Fe), cobalt (Co), and nickel. (Nl) or one of any combination of alloys; (C) annealing the substrate on which the catalyst layer is formed in air at 700 to 900 ° C for about 30 minutes to 9 minutes U) placing the treated substrate in the opposite direction The service towel is heated to 500 meters in a protective gas atmosphere and then reacted with a carbon source gas for about 5 to 30 minutes to grow to obtain a super-aligned carbon nanotube array having a height of 200 to 400 μm. The super-sequential carbon nanotube array is a plurality of pure carbon nanotube arrays formed parallel to each other and perpendicular to the substrate-grown carbon nanotubes. Through the above-mentioned control growth, the super-sequential carbon nanotube array contains substantially no impurities, such as amorphous carbon or (4) all of the particles. The carboniferous tubes in the array of carbon nanotubes are in close contact with each other to form an array by van der Waals forces. Mountain t implements carbon-based carbon acetylene and other chemically active stone anahydrogen compounds, and the protective gas can be selected. ^^Using mouse milk, ammonia gas or inert gas step ^1·Using a pull-in worker 1 / obtaining at least - too rice stone from the husband... Pulling in the carbon nanotube array ^. No..., anti & . The carbon nanotube film is prepared from the carbon nanotubes of the above-mentioned carbon nanotube array. The present embodiment preferably uses a tape-contacting carbon nanotube array having a width of 200841052. Selecting a plurality of carbon nanotube bundles of a certain width *; (b) stretching a plurality of the carbon nanotube bundles at a constant speed along a growth direction substantially perpendicular to the w carbon nanotube array to form a continuous carbon nanotube film. In the above stretching process, the plurality of carbon nanotube bundles are gradually separated from the substrate in the stretching direction under the tensile force, and the selected plurality of carbon nanotube bundles and the other carbon nanotube bundles are respectively end-to-end due to van der Waals force. Connected continuously and continuously to form a thin carbon nanotube film. The carbon nanotube film is a carbon nanotube film having a certain width formed by connecting a plurality of carbon nanotube bundles arranged in a preferred orientation. The arrangement of the carbon nanotubes in the carbon nanotube film is substantially parallel to the stretching direction of the carbon nanotube film. In this embodiment, the width of the carbon nanotube film is related to the size of the substrate on which the carbon nanotube array is grown. The length of the carbon nanotube film is not limited and can be obtained according to actual needs. 01〜100。 The thickness of the carbon nanotube film is 0. 01~100. The thickness of the carbon nanotube film is 0. 01~100 Micron. Step 3: A support is provided, and the above-mentioned carbon nanotube film is adhered and fixed to the support in a predetermined direction to obtain a polarizing element. In this embodiment, the support body can be a square metal fixing frame for fixing the carbon nanotube film, and the material of the carbon nanotube film is not limited, and the excess carbon nanotube film outside the fixing frame can be directly removed. Since the carbon nanotubes in the super-sequential carbon nanotube array 12 200841052 column provided in the first step of the embodiment are very pure, and because the ratio of the beta carbon surface of the carbon nanotube itself is very large, the carbon nanotube film is It has a strong w viscosity. In the third step, the carbon nanotube film can be directly adhered to the fixing frame by its own viscosity, and the periphery of the carbon nanotube film is fixed by a fixing frame, and the middle portion of the carbon nanotube film is suspended. In this embodiment, the support may also be a transparent substrate. The first carbon nanotube film described above can be directly adhered to the surface of the transparent substrate. Those skilled in the art should understand that the size of the support body can be determined according to actual needs. When the width of the support body is larger than the width of the above-mentioned carbon nanotube film, a plurality of the above-mentioned carbon nanotube films can be gap-free. Covered side by side and adhered to the support. It can be understood that, in the third step, the multilayered carbon nanotube film can be adhered and fixed to the support body in the same direction to obtain a polarizing element. The multilayered carbon nanotube film is closely connected by van der Waals force to form a stable multilayer carbon nanotube film structure. The number of layers of the carbon nanotube film is not limited, and can be prepared according to actual needs. Further, the polarizing element obtained above may further treat the carbon nanotube film in the polarizing element using an organic solvent. The organic solvent may be dropped on the surface of the carbon nanotube film by a test tube to infiltrate the entire carbon nanotube film, or the entire frame in which the carbon nanotube film is formed may be immersed in a container containing an organic solvent to infiltrate. The organic solvent is a volatile organic solvent such as ethanol, decyl alcohol, acetone, diethylene bromide or chloroform, and ethanol is preferably used in this embodiment. After the carbon nanotube film is infiltrated with an organic solvent, the parallel carbon nanotube bundles in the carbon nanotube film partially aggregate under the action of the surface tension of the 200841052 hair organic solvent, so after the treatment The carbon nanotube film has a small surface volume ratio, is non-tacky, and has good mechanical strength and toughness. The processed polarizing element can be more conveniently applied to the macroscopic field. Please refer to FIG. 3 and FIG. 4, which are schematic diagrams of scanning electron micrographs (SEM) of the polarizing element before and after treatment with an organic solvent according to an embodiment of the present invention. The carbon nanotubes in the polarizing element of the carbon nanotube film are oriented in a 10 arrangement, and adjacent carbon nanotube films are bonded by van der Waals force. Further, after the carbon nanotube film in the polarizing element obtained above is treated with an organic solvent, the carbon nanotubes in the treated carbon nanotube film are aggregated into a bundle under the action of surface tension. The treated carbon nanotube film has a small surface volume ratio, is non-tacky, and has good mechanical strength and toughness, so that it can be more conveniently applied to the macroscopic field. Referring to FIG. 5, the polarizing element of the present invention uses two layers, five layers, ten layers, 20 layers and 30 layers of nano-disc film as polarizing films respectively, since the carbon nanotubes have uniform absorption characteristics for electromagnetic waves of various wavelengths. Therefore, the polarizing element of the present invention also has uniform polarization absorption properties for electromagnetic waves of various wavelengths. At the same time, it can be clearly seen from Fig. 5 that when the number of layers of the carbon nanotube film is small, the polarizing element has better polarization performance in the ultraviolet band, and the number of layers of the carbon nanotube film in the polarizing element is higher. Many, the higher the degree of polarization of the polarizing element, the better the polarization performance in each band. In summary, the present invention has indeed met the requirements of the invention patent, and 遂 14 200841052 filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. The equivalent modifications or variations made by those skilled in the art to the spirit of the present invention are intended to be included in the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the structure of a polarizing element according to an embodiment of the present invention. Fig. 2 is a flow chart showing a method of preparing a polarizing element according to an embodiment of the present invention. Figure 3 is a scanning electron micrograph of a polarizing element before organic solvent treatment in the embodiment of the present invention. Fig. 4 is a scanning electron micrograph of a polarizing element after treatment with an organic solvent in the embodiment of the present invention. Fig. 5 is a schematic view showing the comparison of polarization degrees of polarizing elements of different layers of carbon nanotube film at respective wavelengths in the embodiment of the present invention. [Main component symbol description] Polarizing element 10 Support body 12 _ Nano carbon tube film 14 15