100年10月14日核正替换頁 1360829 六、發明說明： 【發明所屬之技術領域】 [0001] 本發明涉及一種場發射體及其製備方法。 【先前技術】 [0002] 奈米碳管係一種新型碳材料，由日本研究人員Π jima於 1991 年發現，請參見 “Helical microtubules of graphitic carbon” ，S Iijima， Nature ’vol.354 ，p56( 1991 )。奈米碳管具有優異的導電性能，且其具 有幾乎接近理論極限的尖端表面積（尖端表面積愈小’ 其局部電場愈集中），所以奈米碳管係已知的最好的場 發射材料，它具有極低的場發射電壓，可傳輸極大的電 流密度，並且電流極穩定，因此非常適合做場發射材料 〇 [0003] 先前技術中’將奈米碳管用作場發射的方法主要有直接 生長法和印刷法。其中，直接生長法通常採用化學氣相 沈積法生長奈米碳管陣列作為發射體，其優點為場發射 性能好，其缺點係奈米碳管末端通常發生彎曲，互相交 織。故，為形成良好的發射尖端，需要對奈米碳管陣列 進行後續處理，將奈米碳管陣列的毛輪表面除去，形成 登直的發射尖端’社藝較複雜，且採用這種化學氣相 沉積法難以做成大面積均句的發射體。 國印刷法係將含有奈米碳管的導電衆料或者有機贴結劑印 刷成圖形，这種方法需要引入後續處理方法。因為製備 用於场發射材料的奈米碳管聚料時，通常採用的方式係 把奈米碳管混合到衆料中，或者混合到光刻朦中，這種 096137480 表單編號A0101 笫4 I/此ir答 ^ a 1003377730-0 1360,829 100年10月14日核正替換頁 混合使奈米碳管埋藏在導電漿料層内部，因此需要剝離 一層導電漿漿層，使奈米碳管從導電漿料中露出頭來成 為發射體。請參閱圖1中的發射體結構100，在基底102上 形成一陰極層104，將含有奈米碳管110、粘結劑106和 導電物質108的奈米碳管漿料塗在陰極層104上之後經處 理得奈米碳管複合層112，奈米碳管110埋藏在粘結劑 106和導電物質108的内部。目前採用的奈米碳管複合層 的後處理工藝有印刷加壓法、表面摩擦法、電漿刻蝕法 等。但這些方法一般操作比較複雜，無法實現奈米碳管 印刷層表面圖形的可控性或者可控性較差，且對奈米碳 管造成一定的破壞。請參閱圖2，採用傳統的後處理工序 處理之後，奈米碳管114雖然可以從奈米碳管複合層112 表面露出頭來，然，由於奈米碳管114在處理過程中受到 破壞，其長度往往會減小，因此，奈米碳管114的場發射 平面低於奈米碳管複合層112的平面，將此發射體用作陰 極時，奈米碳管114的場發射平面與陽極的距離大於原奈 米碳管複合層112的表面與陽極的距離，由場發射原理可 知，離陽極越近的發射體發射性能越好，因此奈米碳管 複合層11 2表面少量露出的奈米碳管與奈米碳管114之間 存在場發射競爭，因此需要將奈米碳管複合層112的表面 全部處理，故傳統的奈米碳管複合層的處理方法只適用 於平面發射體，難以實現圖形化。 [0005] 故，確有必要提供一種可圖形化、場發射性能好、操作 簡單的場發射體及其製備方法。 【發明内容】 096137480 表單編號A0101 第5頁/共18頁 1003377730-0 1360829 [0006] 一種場發射體，該場發射體包括一基底 100年10月14日修正替換頁 一陰極層位於 該基底表面及-奈米碳管複合層位於上迷陰極層表面， 其中’該奈米碳管複合層的表面包括至少—個突起部， 該突起部包括至少-個奈米碳管從突起部突出。 [0007] -種場發射體的製備方法，其包括以下步驟：提供一奈 米碳管漿料；提供-基底及—陰極層，該陰極層形成於 該基底上；將上述奈米碳管㈣塗敷於上述陰極層上， 冷卻後，形成一奈米碳管複合層於陰極層上；以一定功 率和掃描速度的鐳射照射奈米碳管複合層表面形成場發 射體。 [0008] 與先前相技術比較’本發明所提供的場發射體係利用錯 射的瞬間高能量的衝擊，使鐘射照射過的奈米碳管複合 層表面的奈米碳管漿料從該表面豎立起來，突起於原奈 米碳管複合層表面，且奈米碳管突出於突起部位的頂部 ，故，這種微觀結構更加有利於場發射，且性能穩定。 另外，本發明所提供的場發射體的製備方法可以通過電 腦控制鐳射光束，使其照射在奈米碳管漿料表面所需要 進行場發射的位置，實現奈米碳管複合層表面場發射的 圖开^化，且由於鐘射照射的過程特別迅速，故，本發明 所心：供的％發射陰極材料的製備方法快速穩定，重複性 好，適合量產β [0009] 【實施方式】 下面將結合附圖及對本技術方案的具體實施例作進一步 的詳細述明》 096137480 請參考圖3， 表單编號Α0101 本技術方案提供一種發射體的製備方法 第6頁/共18 '頁 其 1003377730-0 [0010] 100年10月14日修正#^頁 I36Q829 包括以下步驟： [0011] (一）提供一奈米碳管漿料。 [0012] 所述奈米碳管漿料為奈米碳管和漿料的混合物。其中奈 米碳管為單壁奈米碳管、雙壁奈米碳管、多壁奈米碳管 或其任意組合的混合物。本實施例選用單壁奈米碳管。 [0013] 所述漿料包括無機粘結劑、導電物質和有機溶劑。其中 ，無機粘結劑為絕緣物質，且熔點較低；導電物質包括 金屬和導電聚合物；有機溶劑為易揮發的有機物，可以 通過加熱去除。 [0014] 可以理解，上述漿料還可進一步包括助劑。其中，助劑 包括增粘劑、分散劑和表面活性劑等，以調節漿料的流 動性。 [0015] 本實施例中漿料包括低熔點玻璃粉末、ITO粉末和乙二醇 ，其中低熔點玻璃粉末的熔點為460°C。 [0016] 將奈米碳管與漿料混合，通過攪拌器攪拌得一均勻奈米 碳管漿料，其中，奈米碳管漿料中各物質所占的重量百 分比範圍分別為奈米碳管粉末3-7%，低熔點玻璃粉末 3-7%，ITO粉末8-12%，乙二醇75-95%，優選地，本實 施例中奈米碳管漿料中各物質的重量百分比為奈米碳管 5%，低熔點玻璃粉末5%，ITO粉末10%，乙二醇80%。 [0017] (二）提供一基底及一陰極層，該陰極層形成於該基底 [0018] 基底為玻璃片、塑膠片或其他絕緣物質，優選地，本實 1003377730-0 096137480 表單編號A0101 第7頁/共18頁 1360829 100年10月14日接正替換頁 施例中基底為玻璃片 [0019] [0020] [0021] 陰極層材料為矽、ITO玻璃、# ^ 銀、鋁或其他導電物質，優 選地，本實施例中陰極層枒料為鋁。 陰極層可以通過蒸鍍或者氣* 扎相 >儿積等方法形成於基底上 ’本實施例選用蒸鍍方法。 (三）將上述奈米碳管漿料塗敷於上述陰極層上，然後 在-定溫度下放置-段時間，冷卻後，形成一奈米碳管 複合層於陰極層上。 闕奈米碳管聚料通過滴麗、噴讓、絲網刷膜、旋塗或刷塗 的方式形成於陰極層上》本實施例選用旋塗的方式。 [0023] 所述溫度應高於奈米碳管漿料中有機溶劑的揮發溫度和 無機枯結劑的炫解溫度，所述時間為3 〇分鐘__ 3小時。 [0024] 本實施例中，將奈米碳管漿料塗敷於陰極層上之後，在 500°C下放置1小時，有機溶劑乙二醇揮發除去，同時使 低熔點的玻璃粉熔化，冷卻後，奈米碳管與漿料中IT〇和 低熔點的玻璃較為緊密的結合，形成一奈米碳管複合層 [0025] (四）以一定功率和掃描速度的鐳射光束照射奈米碳管 複合層的表面。 [0026] 本技術方案中，鐳射光束的功率密度為1〇〇〇〇-1〇〇〇〇〇瓦 /平方毫米’掃描速度為800-1500毫米/秒。優選地，本 實施例中’鐳射光束的功率密度為70000瓦/平方毫米， 掃描速度為1 000毫米/秒》 096137480 表單编號Α0101 第8頁/共18頁 1003377730-0 1360.829 [0027] [0028] [0029] [0030] [0031] [0032] 096137480 100年10月14日修正替換頁 確定好奈米碳管複合層表面所需要的圖樣，利用電腦程 式控制鐳射光束的照射路徑，使其照射過後所得到的圖 樣與奈米碳管複合層表面所需圖樣一致。 可以理解，本技術方案中還可以固定鐳射光束，通過電 腦程式控制移動奈米碳管複合層本身，在奈米碳管複合 層表面得到所需圖樣。 由於本技術方案中，鐳射的功率較大，可以在其照射處 產生較高的熱量，又因為掃描速度足夠快，使該處奈米 碳管複合層中的奈米碳管、粘結劑和導電物質因為在短 時間内無法吸收如此多的熱量，而從表面突起，形成至 少一個突起部；在奈米碳管、粘結劑和導電物質突起的 同時，鐳射光束的高熱量會燒掉部分的奈米碳管、粘結 劑和導電物質，由於奈米碳管的熔點最高，因此奈米碳 管從突起部突出。 請參見圖4，本技術方案實施例依據上述方法製備的場發 射體200，其包括一基底202，一位於基底202表面的陰 極層204及位於該陰極層204表面的奈米碳管複合層212 〇 其中基底202可選用玻璃片、塑膠片及其它絕緣物質。本 實施例基底202選用破璃片。 陰極層204材料可為矽、ITO玻璃、銀、鋁或其他導電物 質。本實施例中陰極層204材料選用鋁。 該奈米碳管複合層212包括奈米碳管210、無機粘結劑 206和導電物質208，奈米碳管複合層212的表面包括至 表單編號A0101 第9頁/共18頁 1003377730-0 [0033] 1360829 100年10月14日修正替換頁 少一個突起部220，至少一奈米碳管216突出於該突起部 220頂部，突起部220的底部為起支撐作用的粘結劑214 和導電物質218，其微觀結構請參閱圖5及圖6。其中，奈 米碳管複合層212表面的突起部220可構成所需圖案，直 接應用於場發射。由於奈米碳管216從突起部220的頂部 突出，由場發射原理可知，在同一大小的電場作用下， 離陽極越近的發射體越容易發射電子，因此奈米碳管複 合層212表面的突起部220頂部突出的奈米碳管216具有 更好的場發射性能。 [0034] 圖5為本技術方案所提供的場發射體表面的掃描電鏡圖， 從圖中可以看出，場發射體的表面有至少一突起部，突 起的高度為8-12微米，該突起部包括奈米碳管、粘結劑 和導電物質。由於本技術方案中所選擇的鐳射功率較大 ，可以在其照射處產生較高的熱量，又因為掃描速度較 快，使鐳射照射處的奈米碳管複合層因為在短時間内無 法吸收如此多的熱量，從而使部分的奈米碳管、枯結劑 和導電物質從場發射體表面突起。 [0035] 圖6為圖5中奈米碳管複合層表面突起部的掃描電鏡照片 ，從圖5中可以看出，奈米碳管突出於突起部的頂部，突 起部的底部係起支撐作用的粘結劑和導電物質，由於使 用鐳射光束對奈米碳管複合層的表面進行照射時，在使 奈米碳管、粘結劑和導電物質突起的同時，會燒掉部分 的奈米碳管、粘結劑和導電物質，由於奈米碳管的熔點 最高，因此奈米碳管會突出於突起部的頂部。 [0036] 可以理解，本技術方案所提供的場發射體表面可以製備 096137480 表單编號A0101 第10頁/共18頁 1003377730-0 100年.10月14日接正 出任何所需要的圖案，請參見圖7，圖7係本技術方案所 供的預疋圖案的場發射體的結構示意圖，其中矩形方 框和數位123為鐳射掃描過的地方。圖案的圖樣可以由電 腦程式設計，圖案的準確率高，利用聚焦的鐳射光束， 可以使圖樣的寬度在0. 2毫米以下，滿足平面顯示陰極對 精度的要求；由於圖案可以通過電腦程式設計，因此重 複性好，且操作簡單，快速。 [〇〇37]圖8係利用圖7中的場發射體進行場發射所顯示的圖樣， 其與奈米碳管複合層表面的圖樣一致。 [0038] 綜上所述，本發明確已符合發明專利之要件，遂依法提 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。 【圖式簡單説明】 [0039] 圖1係先前技術中將奈米碳管漿料直接塗敷於基底上作為 場發射體的結構示意圖。 [0040] 圖2係圖1中的場發射體經過後續處理後的結構示意圖。 [0041] 圖3係本技術方案實施例場發射體製備方法的流程圖。 [0042] 圖4係本技術方案實施例所提供的場發射體的結構示意圖 〇 幽]冑5係本技術方案實施例所提供的場發射體表面的掃描電 鏡圖。 096137480 表單編號 第11頁/共18頁 1003377730-0 1360829 100年10月14日核正替換頁 [0044] 圖6係場發射體表面突起部的掃描電鏡圖。 [0045] 圖7係本技術方案實施例所提供的預定圖形的場發射體的 結構示意圖。 [0046] 圖8係利用圖7中的場發射體進行場發射所顯示的圖樣。 【主要元件符號說明】 [0047] 場發射體：100，200 [0048] 基底：102，20 2 [0049] 陰極層：104，204 [0050] 無機粘結劑：106，206，214 [0051] 導電物質：108，208，218 [0052] 奈米碳管：110，114，210，216 [0053] 奈米碳管複合層：112，212 [0054] 突起部：220 1003377730-0 096137480 表單編號A0101 第12頁/共18頁October 14th, 100th, nuclear replacement page 1360829 VI. Description of the invention: [Technical Field of the Invention] [0001] The present invention relates to a field emitter and a method of preparing the same. [Prior Art] [0002] Carbon nanotubes are a new type of carbon material discovered by Japanese researcher Πjima in 1991. See "Helical microtubules of graphitic carbon", S Iijima, Nature 'vol.354, p56 (1991) ). The carbon nanotubes have excellent electrical conductivity and have a tip surface area close to the theoretical limit (the smaller the tip surface area is, the more concentrated the local electric field is), so the carbon nanotubes are the best known field emission materials. It has a very low field emission voltage, can transmit a very large current density, and is extremely stable in current, so it is very suitable for field emission materials. [0003] In the prior art, the method of using nanocarbon tubes as field emission mainly has direct growth method. And printing method. Among them, the direct growth method generally uses a chemical vapor deposition method to grow a carbon nanotube array as an emitter, which has the advantage of good field emission performance, and the disadvantage is that the ends of the carbon nanotubes are usually bent and interwoven. Therefore, in order to form a good emission tip, it is necessary to carry out subsequent processing on the carbon nanotube array, and remove the surface of the wheel of the carbon nanotube array to form a straightened emission tip, which is more complicated and uses this chemical gas. The phase deposition method is difficult to make an emitter of a large area. The printing system of the country prints conductive materials or organic binders containing carbon nanotubes into a pattern. This method requires the introduction of subsequent processing methods. Because of the preparation of carbon nanotubes for field emission materials, the usual method is to mix the carbon nanotubes into the bulk material or mix them into the photolithography crucible. This 096137480 form number A0101 笫4 I/ This ir answer ^ a 1003377730-0 1360,829 October 14, 100 nuclear replacement page mixing allows the carbon nanotubes to be buried inside the conductive paste layer, so it is necessary to peel off a layer of conductive slurry, so that the carbon nanotubes from A head is exposed in the conductive paste to become an emitter. Referring to the emitter structure 100 of FIG. 1, a cathode layer 104 is formed on the substrate 102, and a carbon nanotube slurry containing the carbon nanotubes 110, the binder 106 and the conductive material 108 is coated on the cathode layer 104. Thereafter, the carbon nanotube composite layer 112 is processed, and the carbon nanotubes 110 are buried inside the binder 106 and the conductive material 108. The post-treatment processes of the currently used carbon nanotube composite layer include a printing press method, a surface rubbing method, and a plasma etching method. However, these methods are generally complicated to operate, and the controllability or controllability of the surface pattern of the carbon nanotube printing layer cannot be achieved, and the carbon nanotubes are damaged to some extent. Referring to FIG. 2, after the conventional post-treatment process, the carbon nanotubes 114 can be exposed from the surface of the carbon nanotube composite layer 112. However, since the carbon nanotubes 114 are damaged during the treatment, The length tends to decrease. Therefore, the field emission plane of the carbon nanotubes 114 is lower than the plane of the carbon nanotube composite layer 112. When the emitter is used as a cathode, the field emission plane of the carbon nanotubes 114 and the anode are The distance is greater than the distance between the surface of the original carbon nanotube composite layer 112 and the anode. It is known from the field emission principle that the closer the emitter is to the anode, the better the emission performance, so that the surface of the carbon nanotube composite layer 11 2 is slightly exposed. There is a field emission competition between the carbon tube and the carbon nanotube 114, so the surface of the carbon nanotube composite layer 112 needs to be completely treated. Therefore, the conventional nanocarbon tube composite layer treatment method is only suitable for the planar emitter, which is difficult. Implement graphics. [0005] Therefore, it is indeed necessary to provide a field emitter that can be patterned, has good field emission performance, and is simple to operate, and a preparation method thereof. SUMMARY OF THE INVENTION 096137480 Form No. A0101 Page 5 of 18 1003377730-0 1360829 [0006] A field emitter comprising a substrate on October 14, 100, a modified replacement page, a cathode layer on the surface of the substrate And a carbon nanotube composite layer is located on the surface of the upper cathode layer, wherein the surface of the carbon nanotube composite layer includes at least one protrusion, and the protrusion includes at least one carbon nanotube protruding from the protrusion. [0007] A method for preparing a field emitter, comprising the steps of: providing a carbon nanotube slurry; providing a substrate and a cathode layer, the cathode layer being formed on the substrate; and the carbon nanotube (4) It is coated on the cathode layer, and after cooling, a carbon nanotube composite layer is formed on the cathode layer; the field emitter is formed by irradiating the surface of the carbon nanotube composite layer with laser at a certain power and scanning speed. [0008] Compared with the prior art technique, the field emission system provided by the present invention utilizes the instantaneous high-energy impact of the mis-spraying to make the carbon nanotube slurry on the surface of the irradiated carbon nanotube composite layer from the surface. The erected surface protrudes from the surface of the original carbon nanotube composite layer, and the carbon nanotube protrudes from the top of the protruding portion, so the microstructure is more favorable for field emission and the performance is stable. In addition, the method for preparing the field emitter provided by the invention can control the laser beam to be irradiated on the surface of the surface of the carbon nanotube slurry to perform field emission, thereby realizing surface field emission of the carbon nanotube composite layer. The invention is open, and since the process of the clock irradiation is particularly rapid, the present invention is directed to: the method for preparing the % emission cathode material is fast and stable, and has good repeatability, and is suitable for mass production β [0009] [Embodiment] The specific embodiment of the technical solution will be further described in detail with reference to the accompanying drawings and 096137480. Please refer to FIG. 3, the form number Α0101. The technical solution provides a method for preparing an emitter. Page 6 of 18 pages 1003377730- 0 [0010] October 14, 2014 Revision #^页 I36Q829 includes the following steps: [0011] (1) Providing a carbon nanotube slurry. [0012] The carbon nanotube slurry is a mixture of a carbon nanotube and a slurry. The carbon nanotubes are a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, or a mixture of any combination thereof. In this embodiment, a single-walled carbon nanotube is used. [0013] The slurry includes an inorganic binder, a conductive substance, and an organic solvent. Among them, the inorganic binder is an insulating material and has a low melting point; the conductive material includes a metal and a conductive polymer; and the organic solvent is a volatile organic substance which can be removed by heating. [0014] It will be appreciated that the above slurry may further comprise an adjuvant. Among them, the auxiliary agent includes a tackifier, a dispersant, a surfactant, and the like to adjust the flowability of the slurry. [0015] The slurry in this embodiment includes a low melting point glass powder, an ITO powder, and ethylene glycol, wherein the low melting point glass powder has a melting point of 460 °C. [0016] The carbon nanotubes are mixed with the slurry, and stirred by a stirrer to obtain a uniform carbon nanotube slurry, wherein the weight percentage of each substance in the carbon nanotube slurry is respectively a carbon nanotube Powder 3-7%, low-melting glass powder 3-7%, ITO powder 8-12%, ethylene glycol 75-95%, preferably, the weight percentage of each substance in the carbon nanotube slurry in this embodiment is Carbon nanotubes 5%, low melting glass powder 5%, ITO powder 10%, ethylene glycol 80%. [0017] (b) providing a substrate and a cathode layer, the cathode layer is formed on the substrate [0018] The substrate is a glass sheet, a plastic sheet or other insulating material, preferably, the real 1003377730-0 096137480 form number A0101 seventh Page / Total 18 pages 1360829 October 14th, 100th, the replacement page, the substrate is a glass sheet [0019] [0021] The cathode layer material is tantalum, ITO glass, # ^ silver, aluminum or other conductive materials Preferably, the cathode layer of the present embodiment is aluminum. The cathode layer may be formed on the substrate by vapor deposition or gas phase separation and the like. In this embodiment, an evaporation method is selected. (3) The above-mentioned carbon nanotube slurry is applied onto the above cathode layer, and then left at a constant temperature for a period of time, and after cooling, a carbon nanotube composite layer is formed on the cathode layer. The nano carbon tube aggregate is formed on the cathode layer by means of dripping, spraying, screen brushing, spin coating or brush coating. This embodiment uses a spin coating method. [0023] The temperature should be higher than the volatilization temperature of the organic solvent in the carbon nanotube slurry and the deconstruction temperature of the inorganic binder, which is 3 〇 minutes __ 3 hours. [0024] In this embodiment, after the carbon nanotube slurry is applied onto the cathode layer, it is allowed to stand at 500 ° C for 1 hour, and the organic solvent glycol is volatilized and removed, and the low melting point glass powder is melted and cooled. After that, the carbon nanotubes are tightly combined with the IT crucible and the low melting point glass in the slurry to form a carbon nanotube composite layer. [0025] (4) Irradiation of the carbon nanotubes with a laser beam of a certain power and scanning speed The surface of the composite layer. In the technical solution, the power density of the laser beam is 1〇〇〇〇-1〇〇〇〇〇W/mm 2′, and the scanning speed is 800-1500 mm/sec. Preferably, in the present embodiment, the power density of the laser beam is 70,000 watts/mm 2 and the scanning speed is 1 000 mm/sec. 096137480 Form No. 1010101 Page 8 of 18 1003377730-0 1360.829 [0027] [0028 [0032] [0032] [0032] 096137480 October 14, 100 revised replacement page to determine the pattern required for the surface of the carbon nanotube composite layer, using a computer program to control the illumination path of the laser beam, to illuminate it The pattern obtained afterwards is consistent with the pattern required for the surface of the carbon nanotube composite layer. It can be understood that in the technical solution, the laser beam can be fixed, and the moving carbon nanotube composite layer itself is controlled by the computer program to obtain the desired pattern on the surface of the carbon nanotube composite layer. Due to the high power of the laser in the technical solution, high heat can be generated at the irradiation place, and because the scanning speed is fast enough, the carbon nanotubes, the binder and the carbon nanotubes in the composite layer of the carbon nanotubes are Since the conductive material cannot absorb so much heat in a short time, it protrudes from the surface to form at least one protrusion; while the carbon nanotube, the binder and the conductive substance protrude, the high heat of the laser beam burns off part. The carbon nanotubes, the binder and the conductive material, because the carbon nanotube has the highest melting point, the carbon nanotube protrudes from the protrusion. Referring to FIG. 4 , a field emitter 200 prepared according to the above method includes a substrate 202 , a cathode layer 204 on the surface of the substrate 202 , and a carbon nanotube composite layer 212 on the surface of the cathode layer 204 . In the substrate 202, glass sheets, plastic sheets and other insulating materials may be used. In the embodiment, the substrate 202 is made of a glass granule. The cathode layer 204 material can be tantalum, ITO glass, silver, aluminum or other conductive material. In the embodiment, the material of the cathode layer 204 is aluminum. The carbon nanotube composite layer 212 includes a carbon nanotube 210, an inorganic binder 206, and a conductive material 208. The surface of the carbon nanotube composite layer 212 is included to form No. A0101, page 9 / page 18, 1003377730-0 [ 0033] 1360829 On October 14, 100, the replacement page has one protrusion 220, at least one carbon nanotube 216 protrudes from the top of the protrusion 220, and the bottom of the protrusion 220 is a supporting adhesive 214 and a conductive substance. 218, the microstructure of which is shown in Figure 5 and Figure 6. Among them, the protrusions 220 on the surface of the carbon nanotube composite layer 212 can form a desired pattern and are directly applied to field emission. Since the carbon nanotube 216 protrudes from the top of the protrusion 220, it is known from the field emission principle that the closer the emitter is to the anode, the easier it is to emit electrons under the electric field of the same size, so the surface of the carbon nanotube composite layer 212 is The carbon nanotubes 216 protruding from the top of the protrusions 220 have better field emission properties. [0034] FIG. 5 is a scanning electron micrograph of the surface of the field emitter provided by the present technical solution. As can be seen from the figure, the surface of the field emitter has at least one protrusion, and the height of the protrusion is 8-12 micrometers. The department includes carbon nanotubes, binders and conductive materials. Since the laser power selected in the technical solution is large, high heat can be generated at the irradiation place, and because the scanning speed is fast, the carbon nanotube composite layer at the laser irradiation cannot be absorbed in a short time. A lot of heat, so that part of the carbon nanotubes, the deadener and the conductive material protrude from the surface of the field emitter. 6 is a scanning electron micrograph of the surface protrusion of the carbon nanotube composite layer of FIG. 5. As can be seen from FIG. 5, the carbon nanotube protrudes from the top of the protrusion, and the bottom of the protrusion serves as a support. The binder and the conductive material, when the surface of the carbon nanotube composite layer is irradiated by using a laser beam, a part of the nanocarbon is burned while the carbon nanotube, the binder and the conductive substance are protruded. Tubes, binders, and conductive materials. Because of the highest melting point of the carbon nanotubes, the carbon nanotubes protrude from the top of the protrusions. [0036] It can be understood that the surface of the field emitter provided by the technical solution can be prepared 096137480 Form No. A0101 Page 10 / Total 18 Page 1003377730-0 100 years. On October 14th, any required pattern is received, please Referring to FIG. 7, FIG. 7 is a schematic structural diagram of a field emitter of a pre-patterned pattern provided by the present technical solution, wherein a rectangular box and a digit 123 are laser-scanned places. The pattern of the pattern can be designed by a computer program, and the accuracy of the pattern is high. With the focused laser beam, the width of the pattern can be less than 0.2 mm, which satisfies the accuracy requirement of the flat display cathode; since the pattern can be designed by computer program, Therefore, the repeatability is good, and the operation is simple and fast. [Fig. 8] Fig. 8 is a pattern shown by field emission using the field emitter of Fig. 7, which is identical to the pattern of the surface of the carbon nanotube composite layer. [0038] In summary, the present invention has indeed met the requirements of the invention patent, and the patent application is filed 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. Equivalent modifications or variations made by those skilled in the art to the spirit of the invention are intended to be included within the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS [0039] FIG. 1 is a schematic view showing the structure of a prior art in which a carbon nanotube slurry is directly applied to a substrate as a field emitter. 2 is a schematic structural view of the field emitter in FIG. 1 after subsequent processing. 3 is a flow chart of a method for preparing a field emitter according to an embodiment of the present technical solution. 4 is a schematic structural view of a field emitter provided by an embodiment of the present technical solution. FIG. 4 is a scanning electron micrograph of a surface of a field emitter provided by an embodiment of the present technical solution. 096137480 Form No. Page 11 of 18 1003377730-0 1360829 October 14th, 100th Nuclear Replacement Page [0044] Figure 6 is a scanning electron micrograph of the surface protrusion of the field emitter. 7 is a schematic structural diagram of a field emitter of a predetermined pattern provided by an embodiment of the present technical solution. [0046] FIG. 8 is a pattern displayed by field emission using the field emitter of FIG. 7. [Main component symbol description] [0047] Field emitter: 100, 200 [0048] Substrate: 102, 20 2 [0049] Cathode layer: 104, 204 [0050] Inorganic binder: 106, 206, 214 [0051] Conductive material: 108, 208, 218 [0052] Carbon nanotube: 110, 114, 210, 216 [0053] Carbon nanotube composite layer: 112, 212 [0054] Projection: 220 1003377730-0 096137480 Form No. A0101 Page 12 of 18