車窗外罩注射模具設(shè)計-塑料注塑模側(cè)抽芯1模2腔含proe三維及16張CAD圖帶開題報告.zip

車窗外罩注射模具設(shè)計-塑料注塑模側(cè)抽芯1模2腔含proe三維及16張CAD圖帶開題報告.zip,車窗,外罩,注射,模具設(shè)計,塑料,注塑,模側(cè)抽芯,proe,三維,16,CAD,開題,報告 設(shè)計中期檢查表 系別 學(xué)號 學(xué)生姓名 班級 專業(yè) 指導(dǎo)教師 畢業(yè)設(shè)計（論文）題目 外罩注射模具設(shè)計　 畢業(yè)設(shè)計（論文）進展情況與已完成的工作： 說明書已基本完成。 已完成的工作：2D零件圖 ? ?三維圖 ? ?裝配圖 ? ?外文翻譯 下一步擬進行的工作計劃： 完善說明書，修改圖紙，準(zhǔn)備答辯。 學(xué)生簽名： 年 月 日 指導(dǎo)教師評語： 　 指導(dǎo)教師簽名： 年 月 日 DVD 拾取鏡頭三束光柵的注塑成型和注射壓縮成型 Cheng-Hsien Wu ?, Wei-Shiu Chen 摘要 本文目的在于研究注塑成型和注射壓縮成型在衍射光柵產(chǎn)生中的應(yīng)用。首先設(shè)計模具以便產(chǎn)生一個與固定襯套相連的衍射等級。驗證表明組合件具有良好衍射性能。集成光柵減少了組裝成本和誤差。然后應(yīng)用光刻法制作模具嵌件。并利用田口法和參數(shù)分析法研究模壓工藝參數(shù)對光柵質(zhì)量的影響。接著，介紹并比較結(jié)構(gòu)化模具表面的設(shè)計，制造以及通過注塑成型 (IM)和注射壓縮成型(ICM)的復(fù)制結(jié)果。結(jié)果表明 ICM光柵的衍射角比 IM光柵更精確。通過 ICM制作的光柵產(chǎn)生的翹曲比通過 ICM制作的光柵小很多。衍射圖說明在復(fù)制衍射光柵方面 ICM比IM工藝更好。 關(guān)鍵詞：注塑成型；注射壓縮成型；光柵；復(fù)制 1. 引言 光學(xué)拾取器的所有部件，包括記錄基板和許多組件，都要求有優(yōu)越的光學(xué)性能。這便要求形狀復(fù)制需十分精確且由模塑相關(guān)應(yīng)力引起的光學(xué)各向異性較低。 每當(dāng)行波遇到尺寸與其波長類似的阻塞時，波中的一些能量便會被分散[1,2] 。如果該阻塞周期性出現(xiàn)或的確如果影響波傳播的任意參數(shù)有周期性變化，那么能量則向各個離散方向或衍射級分散，以這種方式發(fā)揮作用的結(jié)構(gòu)可被稱為衍射光柵。 播放器的光學(xué)拾取器中，衍射光學(xué)元件(DOE)不僅用來將主要激光束分割成尋跡追蹤的三個光束，而且使得返回光束向探測區(qū)域偏轉(zhuǎn)。制造光柵的傳統(tǒng)方法是在較好的光學(xué)表面上進行刻劃、拋光或壓花一系列凹槽[3]。 母件通常是DOE原件通過一種或幾種高分辨率光刻步驟組合制造而成的金屬復(fù)制品[4,5]。制造原件的材料可為抗蝕劑、石英、硅或?qū)嵸|(zhì)上任意適合的高分辨率膜或基材。母件一般情況下由電鍍鎳原料制造，但是在有些情況下，其也可為其他材料如石英、塑料或其他金屬，或甚至原料本身。標(biāo)準(zhǔn)光柵首先由一層薄薄的非粘附材料（如金）覆蓋。然后是實質(zhì)層鋁。之后母件通過一層薄薄的低粘度樹脂膠結(jié)到經(jīng)過仔細清潔的復(fù)制坯料上，這使得樹脂在恒溫下聚合（通常是一個緩慢過程）。當(dāng)樹脂固化后，復(fù)制品和母件分離。 作為 DOEs低成本，批量生產(chǎn)的主要技術(shù)，替代性復(fù)制方法如下。這里有三種替代性復(fù)制方法：母本鎳鑄造、壓花和注塑成型 (IM)。 鑄造方法中，在固態(tài)基板上應(yīng)用環(huán)氧樹脂薄膜。在室溫條件下熱固化環(huán)氧樹脂。該方法的主要弊端是固化時間長。還有一種特別感興趣的相關(guān)技術(shù)是將DOEs復(fù)制成涂覆在玻璃或聚合物基質(zhì)上的UV固化材料的薄層。 一種制造光柵復(fù)制品較快的方法是在一定壓力下使其從光滑的支承輥穿過加熱料筒壓印成塑料膜。通常情況下料筒有鎳電鍍包裹圍繞。因為這是一個連續(xù)工藝，單位成本最低，但是質(zhì)量卻僅限于學(xué)生試驗或更可能是裝飾設(shè)備，如全息圖。 注塑成型是一種經(jīng)典的低成本工藝，原則上可以通過將源于一個精密母件鎳電鍍復(fù)制品插入到合適模具中產(chǎn)生光柵。注塑光柵的精度通常受工藝成型條件的限制。所以研究人員應(yīng)更加努力識別影響充型行為的重要因素。 近年來，塑料已經(jīng)表現(xiàn)出巨大的商業(yè)潛能特別是在微結(jié)構(gòu)零件制造方面。注塑成型是制造塑料件的最重要工藝。雖然許多原型塑料微器材通過工程法如激光加工等制造，但是目前全球研究最多的還是微注塑成型法[6,7]。注塑成型的一個優(yōu)勢是，通過此我們可在一個自動化工藝的一次生產(chǎn)步驟中制成復(fù)雜的幾何形狀。許多微器材如手表和照相機組件、汽車碰撞、加速、距離傳感器、硬盤讀/寫頭、CD驅(qū)動器、醫(yī)療傳感器、泵、手術(shù)器械和電信組件等都已經(jīng)被成功地注塑成型。 注塑成型涉及將金屬聚合物注塑到一個模具中使得金屬可冷卻且固化形成一個塑料件。通常來說，這是一個三相工藝，即填充、壓緊和冷卻階段。當(dāng)空腔穩(wěn)定后，產(chǎn)品則從模具中彈出。 盡管有許多優(yōu)勢，注塑成型工藝在模塑微結(jié)構(gòu)方面也有一些固有問題[8]。主要問題是微小腔中的熔融聚合物一接觸相對較冷的腔壁時便立即凍結(jié)。當(dāng)模制具有較高縱橫比的微結(jié)構(gòu)時，情況會更糟糕。但是當(dāng)熔化和模制溫度均高于正常值時便可實現(xiàn)最佳復(fù)制結(jié)果[9]。 注射壓縮成型(ICM) 也有很多優(yōu)點如降低成型壓力、減少殘余應(yīng)力、將分子取向最小化、均勻壓緊、減少不均勻收縮、克服凹痕和翹曲。減少密度變化并提高尺寸精度等。由于這些優(yōu)點，注射壓縮成型通常用來制造高精度尺寸部件，特別對光學(xué)部件來說無殘余應(yīng)力。 [7]沒有應(yīng)用微注塑機而是通過常規(guī)注塑成型法制造亞μm光柵光學(xué)元件。利用兩種不同工藝制成嵌件：SiO2中的反應(yīng)離子蝕刻(RIE)和電子束光刻，緊接著是鎳電鍍。模制溫度為140℃時不存在填充問題。然而， SEM顯微圖則顯示存在一定的形狀偏差，即結(jié)構(gòu)頂部比底部厚。光柵元件間距小于0.5 μm且深度超過1.5 μm。通過在兩個減速元件上分割功能，實際僅需一半填充深度。從而降低形狀偏差的影響。通過與聚碳酸酯注塑成型復(fù)制一個深度為2 μm間距為0.5 μm的光柵結(jié)構(gòu)。 試驗證明較高縱橫比的特性通常難以形成，但是按照設(shè)想，注塑成型的進一步優(yōu)化將解決這些困難[10]。Parashar等人[11]采用兩步驟工藝轉(zhuǎn)移復(fù)制玻璃中的結(jié)構(gòu)：首先，從一個母本結(jié)構(gòu)處獲得一個聚二甲基硅氧烷 (PDMS)復(fù)制品。然后，在PDMS軟復(fù)制品上施用一層溶膠凝膠材料，經(jīng)過干燥和退火后在玻璃中得到微-/納米-結(jié)構(gòu)。他們已經(jīng)在玻璃微-/納米-結(jié)構(gòu)的納米復(fù)制品中，創(chuàng)建了內(nèi)部開發(fā)的衍生自金屬醇鹽的溶膠凝膠材料的有效性。 Obi等人[12]提出了一種制造微結(jié)構(gòu)的復(fù)制方法。將UV固化溶膠凝膠作為一種基礎(chǔ)材料?；A(chǔ)的制造工藝涉及一個犧牲間隔層沉積和模式化以及模制和光刻步驟組合。該制造工藝可應(yīng)用于包含透鏡、衍射光學(xué)元件或波導(dǎo)的光學(xué)MEMS設(shè)備。 本文旨在研究 IM和 ICM工藝在衍射光柵產(chǎn)生中的應(yīng)用。此外應(yīng)用田口法和參數(shù)分析法研究成型參數(shù)對光柵質(zhì)量的影響。論文描述了結(jié)構(gòu)化模具表面的設(shè)計，制造以及通過IM和ICM工藝的復(fù)制結(jié)果。 2. 傳播衍射光柵 2.1 應(yīng)用實例---光學(xué)拾取器 當(dāng)激光束通過衍射光柵時，其被分割成中央明亮和多個側(cè)光束。CD利用中央光束和每側(cè)的一個光束進行系統(tǒng)追蹤?？紤]到CD播放器的一部分包含幾個軌道，如果光學(xué)頭在軌道上，那么主光束便集中在軌道上（凹坑和凸起），二次射束集中在陸地上。三個點彼此之間刻意偏移約20 μm。兩個附加探測器沿主四象限探測器放置以便拾取這些輔助光束。如果三個光束在軌道上，則兩個輔助光電探測器具有等量光，并且相當(dāng)明亮，這是因為它們僅在陸地上追蹤。中央光束的亮度降低，因為其在陸地和凹坑處均進行追蹤。然而，如果光學(xué)頭偏離軌道，則中心點可得到更多光線(因為幾乎沒有凹坑偏離軌道)且側(cè)面探測器也將不平衡。 現(xiàn)代CD播放器中最常見的光學(xué)系統(tǒng)是三光束拾取器，如圖1所示。從激光二極管發(fā)射的光進入衍射光柵。光柵將入射光束轉(zhuǎn)化成中心峰值和一些副峰值。在追蹤機制中主要的中心峰值和兩個副峰值十分重要。三種光束穿過偏振光束分光器。這僅傳播平行于頁面的極化。此時，出現(xiàn)的光（現(xiàn)已與頁面平行極化）是平行的。平行光穿過λ/4板，將其轉(zhuǎn)化為圓偏振光，圓偏振光聚焦后射到盤上。如果光照射到地面上，其將被反射回物鏡。（如果光照射到凹坑，現(xiàn)在為一個凸起處，其不會被反射），然后光再次穿過 λ/4板。因為其以反方向照射，其將在垂直于原始光束的方向偏振（換句話說，現(xiàn)在光朝垂直于紙的方向偏振）。當(dāng)這次垂直的偏振光遇到偏振光束分光器時，其將被反射（不像原來那樣傳播）。因此，其將通過聚焦透鏡反射，然后是柱面透鏡，接著便在光探測器陣列上成像。在自動聚焦機構(gòu)中柱面透鏡十分重要。 2.2 常見的光柵方程 傳輸衍射光柵是一個具有大量平行的幻燈片，并在其上繪制密集間隔縫隙（透明空間）。早期的載玻片是用碳覆蓋的用針尖蝕刻的玻璃載片--現(xiàn)在它們傾向于被印到幻燈片上。入射光顏色分離良好，因為根據(jù)光柵關(guān)系，不同波長的光以不同角度衍射（圖2）： 其中d是狹縫之間的距離，θ為衍射角，λ 光波長，且n為衍射級。 2.3 衍射效率 標(biāo)準(zhǔn)相位光柵的衍射效率，連續(xù)閃耀或多級逼近是衍射微光學(xué)中的一個基本問題。在幾乎所有的光柵應(yīng)用中，主要要求是高衍射效率。實踐中可實現(xiàn)的效率則取決于多個因素：所應(yīng)用制造技術(shù)的類型和性能，以及光柵周期與波長比，材料等。另外由于不存在唯一的衍射效率定義，所以實質(zhì)值也取決于衍射效率定義。因此對于文獻中呈現(xiàn)的結(jié)果，比較起來十分困難。 為了描述衍射光柵的性能，時常應(yīng)用兩個數(shù)字： （1）總效率ηo,1 該總效率被定義為ηo,1 =一階強度/入射光強度 （2）衍射效率ηd,1 衍射效率被定義ηd,1 =一階強度/穿過非結(jié)構(gòu)話基板的投射光強度。 在第二個定義中，由于光柵界面表面粗糙度引起的損耗也包含在效率測量中。本研究中應(yīng)用衍射效率 ηd,1。 3. 試驗步驟 3.1 材料 本研究是使用的材料是聚甲基丙烯酸甲酯的高熱注射級（PMMA, CM-205，來自臺灣奇美公司）。熔體流動指數(shù) 1.8 g/10 min 且體積密度為1.19 g/cm3。建議的料筒溫度在210 到250 ?C之間，推薦的模具溫度在50 到70 ?C之間。材料在成型前使用除濕干燥機于90 ?C環(huán)境下預(yù)干燥4小時。 3.2 零件幾何體和模具設(shè)計 衍射光柵在玻璃基板上加工。加工后，光柵組裝成固定襯套（如圖3 所示）。組裝要求大量生產(chǎn)時間和人力成本。其還產(chǎn)生定位誤差和角度誤差，然后降低光學(xué)拾波器精確度。在該研究中，產(chǎn)品設(shè)計為光柵和套管的組合。整個部件直徑為7 mm。光柵部分直徑為4 mm，位于中心。鎳模具插件設(shè)計周期為20 μm。切口深度為1.5 μm。 中心澆口模架中安裝電鍍鎳模具嵌件如圖4所示。模具有兩個對稱腔位于澆口兩對邊。模板由S45C工具鋼制成?？涨煌ㄟ^一個澆口、兩個澆道和兩個扇形澆口進料，如圖5所示。澆口 48mm長直徑為5 mm。澆道的尺寸為 1.55 mm × 3.50 mm × 5.68 mm。 3.3 模具嵌件制造 我們的光刻工藝涉及光掩膜制造、晶片清洗、旋轉(zhuǎn)涂布、軟烘、曝光、曝光后烘烤、顯影和硬烘烤。 CAD程序中創(chuàng)建的包含特征設(shè)計的高分辨率透明度可作為光刻法中的掩膜。在本研究中，利用高分辨率激光打印機 (16,000 dpi)將掩膜圖案轉(zhuǎn)印到幻燈片上。 圖6為制造鎳電鍍模具嵌件步驟示意圖。硅晶片作為一個基板。為去除晶片表面污染物，晶片清潔便是一個必要步驟以便獲得高性能且高可靠性的產(chǎn)品，還能預(yù)防工藝設(shè)備污染。晶片表面在120 ?C 條件下用4:1 H2SO4/H2O2清洗10分鐘以去除有機污染物。而后用去離子（DI）水清潔晶片表面直至耐水性高于8 K。接著在室溫條件下 用50:1 H2O/HF處理10分鐘以去除化學(xué)氧化物。再次用去離子水清洗晶片表面。清洗后，旋轉(zhuǎn)基板并用加熱氮吹干，然后放置在熱板上（120℃條件下放置3分鐘）以便去除表面的任意水蒸氣。該步驟稱為烘烤脫水。 為了提高對硅晶片的抗粘附性，通常應(yīng)用六甲基二硅烷(HMDS)。通過在室溫下旋轉(zhuǎn)將HMDS應(yīng)用到晶片上。在 90 ?C條件下將晶片置于熱板上2分鐘以便干燥HMDS。下一步驟中將抗蝕劑旋轉(zhuǎn)到晶片上，該步驟應(yīng)在施用HMDS后立即進行。本研究使用AZ9260，正性抗蝕劑。當(dāng)晶片旋轉(zhuǎn)時產(chǎn)生一個均勻?qū)?，此時該抗蝕劑配發(fā)到晶片上。旋涂機的旋轉(zhuǎn)速度增加到 500 rpm，并以 500 rpm/s的加速度加速10s。另外30秒中，旋涂機的旋轉(zhuǎn)速度和加速度分別為300rpm和300rpm / s。該步驟中旋轉(zhuǎn)速度決定了抗蝕劑的最終厚度（本研究中約為50 μm）。 光刻法中的下一步驟為預(yù)烘烤，預(yù)烘烤條件取決于光刻膠厚度。本研究中基板在50 ?C環(huán)境下置放在水平熱板上10分鐘并在90 ?C環(huán)境下置放10分鐘。預(yù)烘烤步驟要達到三個目標(biāo)。首先，大量蒸發(fā)抗蝕劑中的剩余溶劑。其次，抗蝕劑的粘合性得到改善。最后，通過熱松弛可釋放抗蝕劑中的應(yīng)力。然后基板逐漸冷卻到室溫，以便使殘余應(yīng)力最小化。下一步驟為晶片曝光，其可分為三種基本方法：即接觸曬印、接近式曝光和投影曝光。接觸曬印是最早也是最簡單的曬印工藝。掩膜曬印面朝下放置在與晶片抗蝕層直接接觸的地方。然后閃光通過掩膜發(fā)生抗蝕劑曝光。利用接觸式光刻機將掩膜與圖案對準(zhǔn)(Karl Suss MA-6)。掩膜與晶片之間的硬性接觸可損害掩膜和抗蝕層。盡管如此，本研究中應(yīng)用接觸式曬印實現(xiàn)高分辨率曬印能力，曝光時間為3分鐘。 下一步驟為曝光后烘烤(PEB)。該步驟在90 ?C條件下進行1分鐘。PEB后，基板再次逐漸冷卻到室溫以便使應(yīng)力最小化并防止抗蝕劑破裂。基板浸潤到含顯影劑(1:3 AZ400K/DI 水) 的燒杯中約5分鐘，所有特征被開發(fā)后，在新鮮 DI水中清洗光刻膠并用氮吹干。這樣便產(chǎn)生了一個具有正性功能的 AZ9260模具嵌件。 光刻工藝的最后一步是后烘烤用來硬化抗蝕劑并改善其抗蝕刻性。該步驟在 110 ?C條件下進行10分鐘，后烘烤的光刻膠模具在注塑成型中其耐高壓和溫度能力沒有金屬強。這里光刻膠模具用作鎳模具電鍍的一種圖案。濺射一薄金層以便為鎳生長創(chuàng)建一個導(dǎo)電區(qū)域。 表面用淺色硫酸在60 ?C條件下進行預(yù)處理，并用DI 水清洗。在50 ?C，pH等于4，低電流密度4 A/dm2 條件下進行電鍍以便在鎳模具中使內(nèi)部應(yīng)力最小化。電鍍后，用超聲波振動器剝離光刻膠，將鎳結(jié)構(gòu)置于丙酮中并用DI水清洗。整個工藝不到2天完成（包括1小時光刻和40小時電鍍）。 3.4 成型 利用注塑機進行成型操作(FANUC ROBOSHOT S-2000i50A)。該機器可提供高達50噸的夾緊力。螺桿直徑為 22 mm，最大進樣量為29 cm3。該注塑機可提供ICM 工藝和IM 工藝。 每組工藝條件下，進行10次試驗以確保樣品收集前工藝的穩(wěn)定性。如果在前10次運行中沒有觀察到明顯變化，則在接下來5次運行中收集成型部件作為產(chǎn)品表征的樣品。 3.5 質(zhì)量測量 衍射光柵的兩個主要性能使衍射角度的準(zhǔn)確性和衍射效率。試驗裝置如圖7所示，用于測量衍射效率和衍射角度。 He–Ne置放在精確的旋轉(zhuǎn)分度臺上并指向臺中心。測試光柵置放在臺中心。光柵具有指向性這樣激光束可垂直于光柵表面。功率計和光電探測器結(jié)合用來測量光強度。首先將旋轉(zhuǎn)臺旋轉(zhuǎn)至光電探測器接收最大強度的方向。即，0階光線在光電探測器中心準(zhǔn)確輻照。然后將旋轉(zhuǎn)臺調(diào)零。其次，將旋轉(zhuǎn)臺旋轉(zhuǎn)至1階光線在光電探測器中心準(zhǔn)確輻照的方向。旋轉(zhuǎn)角度為+1階的衍射角，實驗結(jié)果表明?1階的衍射角與+1階衍射角十分接近。因此，本研究中僅測量+1階的衍射角。 4. 田口參數(shù)設(shè)計 研究分析并比較了工藝參數(shù)對注塑成型光柵和注射壓縮成型光柵衍射角的影響。這里應(yīng)用田口法，找出每個因素的貢獻率并測定在兩個成型工藝中驅(qū)動有效因素的參數(shù)最佳組合，以便得到具有最精確衍射角的產(chǎn)品。 分析中，信噪(S/N) 比是統(tǒng)計量表示響應(yīng)信號功率處以由于噪聲引起信號變化的功率。 S/N的最大化導(dǎo)致對噪聲敏感的任何性能將最小化。為優(yōu)化IM和ICM衍射光柵，我們可用“名義上最佳”的方程進行分析： 其中μ 是平均性能，σ 為標(biāo)準(zhǔn)偏差，yi測量的性質(zhì)， n為每次測試試驗中樣品數(shù)量。然后總結(jié)具有最大S/N比的最佳因子水平，這將在噪聲范圍內(nèi)使靈敏度最小化。 該實驗?zāi)康氖菧y定成型因素對衍射角和最佳因素組合的影響。通過這種最佳工藝條件，衍射角與理論值最接近。根據(jù)我們的最初測試和之前的文獻綜述[13–15]，兩種工藝選擇四個成型因素。注塑成型為熔融溫度、注射速度、成型溫度和壓緊壓力。每個因素都有三個級別，如表1所示，這是因為這些因素對結(jié)果的影響呈非線性變化。對于注射壓縮成型而言，選擇的四個因素為成型溫度、注射速度、壓縮速度和壓縮周期，如表2所示。根據(jù)每個參數(shù)等級，應(yīng)用 L9(34)正交表進行測試。 5. 結(jié)果 5.1 最佳成型參數(shù)組合 圖8和9分別描述了 IM和ICM工藝中工藝因素對衍射角精確度的影響。這些響應(yīng)圖說明各因素之間如何使精確度發(fā)生變化。從圖8可看出，在熔融溫度240 ?C，注射速度為150 mm/s，成型溫度為60 ?C，且壓緊壓力為100 MPa條件下因素各等級將產(chǎn)生最小誤差。最佳工藝條件下，進行四次確認(rèn)測試，則測量的衍射角為 0.988?, 0.985?, 0.987?和 0.984? 平均值為0.986，相應(yīng)S/N比為54.65。確認(rèn)測試中計算的 S/N 比位于確認(rèn)區(qū)間內(nèi) [52.38, 83.42]。確認(rèn)測試結(jié)果表明本研究中恰當(dāng)應(yīng)用了田口法（表3和表4）。 5.2 成型因素對衍射角精確度的影響 在之前的分析中，每個因素對衍射角精確度整體影響的貢獻用百分比表示。對于 IM 光柵來說，成型溫度的影響最大，貢獻率為57.41%，其次為熔融溫度為19.23%，壓緊壓力 19.1%和注射速度 4.25%。而對于ICM光柵而言，壓縮速度的影響最大，貢獻率為55.7%，其次為壓縮周期為26.0%，注射速度14.3% 和成型溫度 4.02%。 5.3 IM 和ICM部件之間的比較 在各自最佳工藝條件下，通過 IM和ICM制造部件。我們通過比較 IM和 ICM部件質(zhì)量研究這兩種工藝。圖10描述了 IM 光柵和 ICM光柵的衍射性能。從圖中可看出ICM 光柵提供比IM光柵更集中的衍射圖案。這說明 ICM光柵的光學(xué)質(zhì)量比IM光柵好。此外，根據(jù)測量的衍射角和觀察的表面質(zhì)量研究光柵。接著，通過測量光柵表面的表面輪廓研究表面特性。 5.3.1 衍射角測量 激光波長為685 nm。本研究中衍射光柵的間距為40 μm。根據(jù)方程式（1）預(yù)測的衍射角為0.9812?。對IM工藝而言，確認(rèn)測試的結(jié)果表明平均最佳衍射角為0.986?。而對于 ICM工藝而言，衍射角為0.983?，其與預(yù)測的衍射角更接近一些。 5.3.2 顯微鏡技術(shù) 掃描電子顯微鏡（JOEL，JSM-6400）中驗證模制光柵。首先將樣品切成小塊并用金在表面濺射，接著用掃描電子顯微鏡(SEM)觀察。圖11是 IM光柵和ICM光柵的SEM 顯微照片。它們的形狀和尺寸看起來類似。為了獲得更清晰的立體圖，我們使用另一臺顯微鏡（具有OPTEM Zoom 125光學(xué)系統(tǒng)的SONY Exwave HAD攝像機）。經(jīng)過仔細觀察發(fā)現(xiàn) ICM 光柵比IM光柵復(fù)制更好（圖12）。ICM光柵有一個邊緣比IM光柵更鋒利的凹槽。此外，IM光柵比ICM光柵含更多空隙。 5.3.3 表面輪廓測量 為測量微結(jié)構(gòu)輪廓，我們使用高性能表面輪廓儀（XP-2, Ambios Technology Inc.）測量 IM光柵和 ICM光柵。表面輪廓如圖13所示。在接近中心的光柵表面進行測量。光柵的中心點表示為表面輪廓的A點。在A點的17個周期處，表示為B點。兩個輪廓的A點和B點之間的水平距離約為 670 μm。周期也大致相同，但是對IM輪廓來說，兩點之間的垂直距離（23.6 μm）大于 ICM 輪廓的垂直距離（9.2 μm）。垂直偏差顯示光柵翹曲。結(jié)果表明 ICM光柵的翹曲比IM 光柵小得多。 6. 結(jié)論 本文旨在研究應(yīng)用 IM和ICM制造衍射光柵。文中利用田口法和參數(shù)分析探索模制參數(shù)對光柵質(zhì)量的影響。此外，研究描述了 結(jié)構(gòu)化模具表面的設(shè)計和制造以及IM 和ICM工藝復(fù)制結(jié)果。 根據(jù)實驗結(jié)果得出以下結(jié)論： （1） 利用 IM和ICM工藝可制造衍射光柵。模具用來制造與固定襯套連接的衍射光柵。經(jīng)驗證實結(jié)合件具有良好的衍射性能。集成光柵消除了組裝成本和誤差。根據(jù)光刻工藝制造模具嵌件。 （2） 對于注塑成型的光柵而言，模具溫度影響最大，其次是熔融溫度、壓緊壓力和注射速度。而對于注射壓縮成型的光柵而言，壓縮速度影響最大，其次是壓縮周期、注射速度和模具溫度。 （3） 衍射圖案表明在復(fù)制一個衍射光柵方面 ICM工藝比IM更好。 ICM光柵衍射角比 IM光柵更精確。ICM工藝比注塑成型提供更精確的形狀復(fù)制。通過ICM制造的光柵，其產(chǎn)生的翹曲比IM制造的光柵小得多。 Sensors and Actuators A 125 2006 367 375 Abstract dif a The structured compared that K 1 strate optical cation related dimensions w if propagation directions w DOE track detector is optical 0924 4247 doi 10 1016 j sna 2005 07 025 Injection molding and injection compression molding of three beam grating of DVD pickup lens Cheng Hsien Wu Wei Shiu Chen Department of Mechanical and Automation Engineering Da Yeh University Chang Hwa 51505 Taiwan Received 21 January 2005 received in revised form 8 July 2005 accepted 14 July 2005 Available online 5 October 2005 The objective of this paper is to investigate the application of injection molding and injection compression molding processes to produce fraction gratings A mold was designed to produce a diffraction rating connected with the fixed bushing The combined part was verified to have good diffraction performance Integrated grating eliminates the assembly cost and error Photolithography was applied to make the mold insert Taguchi method and parametric analysis were applied to study the effects of molding parameters on grating quality The design fabrication of mold surfaces and the results of the replication by injection molding IM and injection compression molding ICM are presented and The diffraction angle of ICM grating is more accurate than that of IM grating Grating made by ICM has a much smaller warpage than made by IM The diffraction pattern shows that ICM is a better process than IM to replicate a diffraction grating 2005 Elsevier B V All rights reserved eywords Injection molding Injection compression molding Grating Replication Introduction The master is usually a metal copy of a DOE original fabri cated by one or a combination of high resolution lithographic All parts in an optical pickup including the recording sub and a number of components are required to have superior performance This requires a very accurate shape repli and low optical anisotropy as induced by the molding stresses Whenever a travelling wave encounters an obstruction with similar to its wavelength some of the energy in the ave is scattered 1 2 If the obstruction is periodic or indeed there is a periodic variation of any parameter which affects the of the wave energy is scattered into various discrete or diffracted orders and a structure which acts in this ay may be referred to as a diffraction grating In the optical pickup of the player diffractive optical elements are used to split the main laser beam into three beams for following but also to deflect the returning beam onto the area The classical method of manufacturing gratings to scribe burnish or emboss a series of grooves upon a good surface 3 Corresponding author Tel 886 4 8511227 fax 886 4 8511224 E mail address chengwu mail dyu edu tw C H Wu steps be film original can or a follo cemented carefully at resin e production of There nick strate ies time see front matter 2005 Elsevier B V All rights reserved 4 5 The material in which the original is fabricated can resist quartz silicon or virtually any suitable high resolution or substrate The master is typically fabricated from the by electroplating in nickel although in certain cases it be another material such as quartz plastic or another metal even the original itself The master grating is first coated with thin layer of some non adherent material e g gold This is wed by a substantial layer of aluminum The master is then with the aid of a thin film of a low viscosity resin to the cleaned replica blank allowing the resin to polymerize a constant temperature generally a slow process When the has cured the replica and the master are separated How ver the process takes too much time and is not suitable for mass To be a major technology for the low cost mass production DOEs alternative replication methods are applied as follows are three alternative replication methods to replicate the el master casting embossing and injection molding IM In casting a thin film of epoxy is applied on a solid sub blank Both room temperature and thermally cured epox have been used The main disadvantage is the long curing A related technique of particular interest for DOEs is the 368 and Actuator replication glass embossing under will Since mal decorati ciple replica The the to iors mercial parts for tic methods currently tant mak mated components read write pumps nents polymer a filling stable e 8 ca ca high were than such minimizing une density of emplo of W ments tw electron beam filling 140 de bottom 0 5 tion half can and polycarbonate tinely tion al structure is sol gel micro nano structure ha materials glass micro structures The of tolithography optical or of T C H Wu W S Chen Sensors into a thin film of UV curable material coated onto a or polymer substrate An even faster method of making grating replicas involves a plastic film by passing it over a heated cylinder some pressure from a smooth back up roll The cylinder typically have a nickel electroplated wrapping around it this is a continuous process the unit cost will be mini but quality is limited to student experiments or more likely ve devices such as holograms Injection molding is a classic low cost process and in prin could produce gratings by inserting a nickel electroplated derived from a precision master into appropriate molds accuracy of injection molded gratings is always limited by molding conditions of the process Efforts need to be made identify the significant factors that affect micro filling behav In recent years plastics have begun to show great com potential especially in manufacturing micro structured Injection molding represents the most important process manufacturing plastic parts While many prototype plas micro devices are fabricated using precision engineering such as laser machining micro injection molding is being investigated all over the world 6 7 An impor advantage of injection molding is that with it we can e complex geometries in one production step in an auto process Many micro devices such as watches and camera automotive crash acceleration distance sensors heads of hard discs CD drives medical sensors surgical instruments and telecommunications compo have been successfully injection molded The injection molding process involves the injection of a melt into a mold where the melt cools and solidifies to form plastic part It is generally a three phase process including packing and cooling phases After the cavity becomes the product is ejected from the mold Despite many advantages the injection molding process xperiences some inherent problems in molding micro features The main difficulty is that the molten polymer in a tiny vity instantaneously freezes upon touching the relatively cold vity wall The problem gets worse when micro features with aspect ratios are to be molded The best replication results achieved when melt and mold temperatures were higher normal values 9 Injection compression molding ICM has the advantages as decreasing molding pressure reducing residual stress molecular orientation packing evenly reducing ven shrinkage overcoming sink mark and warpage reducing variation and increasing dimensional accuracy Because these advantages injection compression molding is often yed to produce parts of high accurate dimension and free residual stress especially for the optical parts Instead of using a micro injection molding machine imberger Friedl 7 fabricated sub H9262m grating optical ele by conventional injection molding Inserts were made by o different processes reactive ion etching RIE in SiO 2 and lithography followed by nickel electroplating No problem was encountered with a mold temperature of the design of 2 2 1 it beams by CD track pits on 20 placed these tw will central on then of three beam s A 125 2006 367 375 C However SEM micrographs show that there is a shape viation i e the structures are thicker at the top than at the Grating elements were designed to have a pitch below H9262m and depths in excess of 1 5H9262m By splitting the func over the two surfaces of the retardation elements only a filling depth was necessary The effect of shape deviation be reduced Grating structures with a record depth of 2H9262m a pitch of 0 5H9262m were replicated by injection molding with Features with high aspect ratio proved difficult to form rou however it is envisaged that further optimization of injec molding will resolve these difficulties 10 Parashar et 11 employed a two step pattern transfer to replicate the in glass first a polydimethylsiloxane PDMS replica obtained from a master structure and secondly a layer of material is applied on the PDMS soft replica to get in glass after drying and annealing They ve established the effectiveness of in house developed sol gel derived from metal alkoxides in nano replication of micro nano structure Obi et al 12 presented a replication method to fabricate UV curable sol gel is used as base material basic fabrication process involves deposition and patterning a sacrificial spacer layer and a combined molding and pho step This fabrication process can be applied for MEMS devices that incorporate lenses diffractive optics waveguides The objective of this paper is to investigate the application IM and ICM processes to produce diffraction gratings The aguchi method and parametric analysis were applied to study effects of molding parameters on the grating quality The fabrication of structured mold surfaces and the results the replication by IM and ICM are presented Transmission diffraction grating Application example optical pickup When the laser beam goes through the diffraction grating is split up into a central bright beam plus a number of side The central beam and one beam on each side are used the CD for the tracking system Consider a segment of the player containing several tracks If the optical head is on then the primary beam will be centered on a track with and bumps and the two secondary beams will be centered land The three spots are deliberately offset approximately H9262m with respect to each other Two additional detectors are alongside the main quadrant detector in order to pickup subsidiary beams If the three beams are on track then the o subsidiary photodetectors have equal amounts of light and be quite bright because they are only tracking on land The beam will be reduced in brightness because it is tracking both land and pits However if the optical head is off track the center spot gets more light because there are fewer pits f track and the side detectors will be misbalanced The most common optical train in modern CD players is the pickup depicted in Fig 1 The light is emitted by the and Actuator laser the peak anism This ing The into then reflected no the will w paper beam before the The nism 2 2 of Early point no at lengths the d where tion 2 3 uously issue gratings ment C H Wu W S Chen Sensors Fig 1 Schematic illustration of an optical pickup diode and enters a diffraction grating The grating converts light into a central peak plus side peaks The main central and two side peaks are important in the tracking mech The three beams go through a polarizing beam splitter only transmits polarizations parallel to the page The emerg light now polarized parallel to the page is then collimated collimated light goes through a 4 plate This converts it circularly polarized light The circularly polarized light is focused down onto the disk If the light strikes land it is back into the objective lens If the light strikes the pit w a bump it is not reflected The light then passes through 4 plate again Since it is going in the reverse direction it be polarized perpendicular to the original beam in other ords the light polarization is now vertical with respect to the When the vertically polarized light hits the polarizing splitter this time it will be reflected not transmitted as Thus it will reflect through the focusing lens and then cylindrical lens and be imaged on the photodetector array cylindrical lens is important in the auto focusing mecha The general grating equation A transmission diffraction grating is a slide with large number parallel closely spaced slits transparent spaces drawn on it ones were carbon covered glass slides etched by a needle w they tend to be printed onto a slide It is excellent separating the colors in incident light because different wave are diffracted at different angles Fig 2 according to grating relationship sin n 1 d is the distance between the slits the angle of diffrac the wavelength of the light and n is the order of diffraction Diffraction efficiency Diffraction efficiencies of standard phase gratings contin blazed or multilevel approximations are a fundamental in diffractive micro optics In nearly all applications where are used a high diffraction efficiency is a major require Achievable efficiency in practice depends on numerous f ogy etc dif Therefore appear ings 1 2 surf measurement cienc 3 3 1 of Corp density between ture for 3 2 machining s A 125 2006 367 375 369 Fig 2 A transmission grating actors the type and performance of the fabrication technol used the grating period to wavelength ratio the materials Additionally the actual value depends on the definition of fraction efficiency since a unique definition does not exist it is often quite difficult to compare results which in the literature In order to characterize the performance of diffraction grat two numbers are often used The overall efficiency o 1 This overall efficiency is defined as o 1 intensity of first order intensity of incident beam The diffraction efficiency d 1 The diffraction efficiency is defined as d 1 intensity of first order intensity of transmitted beam through unstruc tured substrate With the second definition losses due to scattering from ace roughness at the grating interface are contained in the of efficiency In this study the diffraction effi y d 1 is used Experimental procedures Material The material used in this study is a high heat injection grade polymethylmethacrylate PMMA CM 205 from Chi Mei Taiwan The melt flow index is 1 8 g 10 min and the bulk is 1 19 g cm 3 The recommended barrel temperature is 210 and 250 C and the recommended mold tempera between 50 and 70 C The material was pre dried at 90 C 4 h using a dehumidifying drier before molding Part geometry and mold design Diffraction gratings were machined on a glass substrate After the grating has to be assembled into a fixing bushing 370 and Actuator as and and the whole diameter w 1 5 gated symmetrically mold a sprue runners 3 3 tion e design photolithography ferred 16 000 to w Fig Fig 5 Schematic illustration of cavity arrangement remove contaminants from the wafer surface in order to obtain C H Wu W S Chen Sensors Fig 3 The grating and the fixing bushing shown in Fig 3 Assembly requires much production time labor cost It also creates positioning error and angle error then reduces the accuracy of an optical pickup In this study product was designed to combine grating and bushing The part has a diameter of 7 mm The grating portion with a of 4 mm is located at the center The nickel mold insert as designed with a periodicity of 20H9262m The notch depth was H9262m The electroplated nickel mold insert was installed in a center mold base as shown in Fig 4 The mold has two cavities located on the opposite sides of the sprue The plates are made of S45C tool steel The cavity is fed by sprue two runners and two fan gates as shown in Fig 5 The is 48mm long and 5 mm in diameter The dimensions of are 1 55 mm 3 50 mm 5 68 mm Mold insert fabrication Our photolithography process involves photomask fabrica wafer cleaning spin coating soft baking exposure post xposure baking developing and hard baking A high resolution transparency containing the features created in a CAD program was used as the mask in In this study the mask pattern was trans onto a transparency using a high resolution laser printer dpi Fig 6 shows the schematic of the fabrication steps required produce a nickel electroplated mold insert A silicon wafer as used as the substrate Wafer cleaning is a necessary step to 4 A center gated mold base with an electroplated nickel mold insert high v cleaned or ized 50 1 to deionized spun hot surf amethyldisilane the placing is diately w while w Fig s A 125 2006 367 375 performance and high reliability of products and to pre ent contamination of process equipment The wafer surface was with a 4 1 H 2 SO 4 H 2 O 2 for 10 min at 120 C to remove ganic contaminants The wafer surface was rinsed using deion DI water until the water resistance was higher than 8 Omega1 A H 2 O HF step for 10 min at room temperature was applied remove chemical oxides The wafer surface was rinsed using water again After wafer cleaning the substrate was blown dry using heated nitrogen and then placed on a plate 120 C for 3 min to drive off any water vapor on the ace This step is called dehydration baking To improve the adhesion of resists to the silicon wafer hex HMDS is often applied HMDS was applied to wafer by spinning at room temperature HMDS was dried by the wafer on a hot plate for 2 min at 90 C The next step spinning the resist on to the wafer and it should be done imme after the HMDS application A positive resist AZ9260 as used in this study The resist is dispensed onto the wafer the wafer is spinning to produce a uniform layer on the afer The spin speed of the spin coater was increased to 500 rpm 6 Fabrication schematic to produce nickel electroplated mold inserts and Actuator with spin 300 the conditions study for plishes lar Finally ation temperature is ods Contact The resist by w The damage printing capability ried gradually mize w AZ400K DI de blo insert bak resistance bak the photoresist mold for rinsed a minimize ing nick w 1 h 3 4 ing can is machine Fig 7 Experimental set up used to measure the diffraction efficiency of gratings and diffraction pattern of a laminar grating structure under laser illumination Under each set of process conditions 10 shots were made to ensure that the process was stable before samples were col lected If no significant variation was observed during these first 10 runs the molded parts from the next 5 runs were collected as the samples for product characterization 3 5 Quality measurement Two major performances of a diffraction grating are the accu C H Wu W S Chen Sensors an acceleration of 500 rpm s for 10 s For another 30 s the speed and acceleration of the spin coater were 300 rpm and rpm s respectively The spin speed at this step determines final thickness of the resist about 50H9262m in this study The next step in the lithography is the pre bake Pre bake depend on the thickness of the photoresist In this the substrate was placed on a leveled hot plate at 50 C 10 min and at 90 C for 10 min The pre bake step accom three things Firstly the remaining solvent in the resist gely evaporates Secondly adhesion of the resist improves stresses in the resist are relieved through thermal relax The substrate was then gradually cooled down to room in order to minimize residual stresses The next step wafer exposure which can be divided into three basic meth contact printing proximity printing and projection printing printing is the oldest and the simplest printing process mask is placed print side down in direct contact with the layer on the wafer Exposure of the resist then takes place shining light through the mask Aligning the mask to patterns as carried out with a contact mask aligner Karl Suss MA 6 hard contact between the mask and the wafer results in to both the mask and the resist layer However contact was applied in this study for its high resolution printing Exposure time was 3 min The next step is a post exposure bake PEB PEB was car out at 90 C for 1 min After PEB the substrate was again cooled down to room temperature in order to mini stresses and prevent the resist from cracking The substrate as immersed into the beaker containing the developer 1 3 water for about 5 min After all th