200304579 玖、發明說明 【發明所屬之技術領域】 本發明係有關微透鏡片，特別係有關使用在背面投影 型投影電視用影像顯示幕（透過型投影幕或背面型投影幕）上 極爲有效之微透鏡片。 又，本發明係有關用於液晶投影電視/顯示器等背面投 影型顯示器（電視/顯示器）之投影幕，該投影幕係使用透鏡 陣列片而成者。 【先前技術】 一般而言，透過型投影幕係藉由菲涅耳（Fresnel)透鏡 片和雙凸透鏡片（lenticular sheet)之組合來構成。 菲涅耳透鏡片係藉由凸透鏡特性，把來自投影機之投 影光（從小口徑透鏡進行散射）當作大致並行光，而射出於雙 凸透鏡片側。 雙凸透鏡片係將藉菲涅耳透鏡片形成大致並行光而射 入之投影光，藉由沿水平方向排列之柱面透鏡群之特性， 朝水平方向擴散’在觀賞者側’作爲顯示光而射出。 又，在背面型投影幕中，亦朝垂直方向擴散顯示光， 使來自投影機之投影光成像’減低因投影機之透鏡爲小口 徑所造成之影像所不要之閃爍等目的，在慣用上形成光擴 散層。 光擴散層係由雙凸透鏡片、菲涅耳透鏡片、或當作保 護板功能之最外面之則面板等之至少~種所形成’當形成 時，係採用塗布、積層、混入等適當之手法。 200304579 近年來，取代3管式（R、G、B)之CRT方式之投影機 ，使用液晶式投影機、和ΤΙ(德州儀器）公司之註冊商標之 「DMD(Digital Micromirror Device)或 DSP(Digital Light200304579 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to a microlens sheet, and particularly relates to a micro lens that is extremely effective for use on an image display screen for a rear projection type projection television (a transmission type projection screen or a rear type projection screen). Lens sheet. The present invention relates to a projection screen used for a rear projection type display (television / display) such as a liquid crystal projection television / display. The projection screen is a lens array sheet. [Prior Art] In general, a transmissive projection screen is constituted by a combination of a Fresnel lens sheet and a lenticular sheet. The Fresnel lens sheet uses the convex lens characteristics to treat the projection light from the projector (scattered from the small-aperture lens) as approximately parallel light and exits from the side of the lenticular lens sheet. The lenticular lens sheet is a projection light that is incident by the Fresnel lens sheet to form substantially parallel light. The lenticular lens sheet diffuses in the horizontal direction 'on the viewer's side' as display light due to the characteristics of the cylindrical lens group arranged in the horizontal direction. Shoot out. In the rear-type projection screen, display light is also diffused in the vertical direction, so that the projection light from the projector is imaged to reduce the flicker that is not necessary for the image caused by the small diameter of the projector lens. Light diffusion layer. The light diffusing layer is formed of at least one of a lenticular lens sheet, a Fresnel lens sheet, or an outermost panel that functions as a protective plate. 'When formed, appropriate methods such as coating, lamination, and mixing are used. . 200304579 In recent years, instead of three-tube (R, G, B) CRT projectors, LCD projectors and "DMD (Digital Micromirror Device) or DSP (Digital Light
Processing )」之稱爲反射型光閥（light valve)方式之單管式 投影機而成之顯示裝置正在普及，針對這些新裝置方面， 要求較佳之背面型投影幕。 本申請人已提案背面型投影幕，該背面型投影幕係備 有曰本特開平9-120101號公報、特開平8-269546號公報、 特開平10-83029號公報所例示之雙凸透鏡片。這些公報係 有關雙凸透鏡片，都必須備有光擴散層，具有沿水平方向 排列之柱面透鏡群，在任一柱面透鏡群內部，具有充分之 光擴散特性。 如上述，藉由習知之雙凸透鏡片之顯示光之視角（範圍） 之控制，在透鏡功能上，只能控制水平方向，垂直方向之 控制係依存光擴散層。 雖藉由透鏡功能之視角控制之效果很高且快速，但藉 由光擴散層之視角控制之效果係相對地變低且緩慢之故。 一般而言，光擴散層係藉由在樹脂中分散混合光擴散 性微粒子來形成。不僅不易選定光擴散性微粒子和前述樹 脂之折射率差、光擴散性微粒子之粒徑（及其分布）、或分散 適合性等較佳之兩者之組合，而且，在構造上，不易控制 僅垂直方向之光擴散性，水平方向之光擴散性也必然會受 到影響。 又，所謂提高光擴散性，因需要光擴散性微粒子之過 200304579 剩混入，故會導致透過光之衰減（降低顯示亮度），並且提高 成本。 藉由透鏡功能，冀望水平/垂直雙方之光擴散性之試驗 也依照習知來進行，但除了在用來控制水平方向之光擴散 性之透鏡片，追加用來控制垂直方向之光擴散性之透鏡片 之手法，在投影幕之組品化上，兩者之透鏡之調整困難， 導致因增加構件而提高成本。 用菲涅耳透鏡片和雙凸透鏡片之組合所構成之投影幕 ，來取代雙凸透鏡片，採用即使在水平以外之方向，亦可 藉由透鏡功能來控制光擴散性之構成之透鏡片之手法，也 在特開2000-131506號公報等被提出。 根據上述公報之提案係備有微透鏡陣列部之微透鏡片 ，該微透鏡陣列部係形成有在光學上，將作成凹或凸之旋 轉對稱形狀之微透鏡，將該形狀作成菱形排列之層。在這 些提案中，必須要有在射出面側配置擴散片層，或在前述 微透鏡陣列部內部施加擴散劑之片層。 至於上述之新裝置，係如以XGA等爲代表，爲了提供 高解析度之畫質，而限定投影影像之面板（液晶和微反射鏡 陣歹[])也對應像素數之增加，進行高精細化，在投影幕側， 也冀望柱面透鏡群之排列間距之高精細化。 又，單元透鏡之排列間距係隨著進行高精細化，形成 在透鏡部相反側之遮光圖案（BM= Black Matrix)之透光部也 進行高精細化，在藉由微透鏡陣列部之聚光部，要求形成 鮮明之開口部之精度。 200304579 當黑基質具有高精細透鏡部之透鏡片時’係利用透鏡 部本身（對形成在透鏡片相反側之透鏡面之感光性樹脂層）之 聚光特性，界定正確對應於個個透鏡部之非聚光部之位置 ，即藉由所謂之自調準之方式來加以形成。 在自調準方式中，有濕方式（在已曝光之感光性樹脂層 ，施以顯影處理後，形成遮光圖案），和乾方式（在已曝光之 感光性樹脂層，不施以顯影處理，而加以著色，來形成遮 光圖案）。 在乾方式中，係使用感光性黏著劑（對應感光/非感光， 具有產生有/無黏著性之特性），對應黏著性之有無，進行著 色。 就透過型液晶投影幕而言，爲了形成較佳之遮光率（經 驗上，在影像之對比上，以60%以上之範圍爲佳）之黑基質 ，藉由透鏡部之聚光（聚焦）位置，不是在感光性樹脂層之射 出面側，而是在感光性樹脂層之內部，對應所形成之圖案 之遮光率，適當加以設定。 當透鏡形狀爲球面時，焦點位置（透鏡中心部和端部）會 因像差而不同，當藉由自對準方式來形成遮光圖案時，感 光性樹脂層之變性處不能明確決定，開口部和遮光部之邊 界不易變爲鮮明。 特別是，當冀望高對比化，來提高遮光率時，單元透 鏡之排列間距係高精細，個個單元透鏡越是微小，微小之 開口部和遮光部之邊界有越不易形成鮮明的黑基質等問題 200304579 又，現在市售之背面投影型電視等所使用之習知之透 過型投影幕，一般之構成係設置有：菲涅耳透鏡，大致上 在單面形成同心圓狀之凸凹；雙凸透鏡’使圓筒狀之柱面 透鏡朝單方向排列配設而成；及擴散層，設置在其任一側 或單側、或是設置在其他之基材上。 構成這些透過型投影幕之元件，首先，係藉菲涅耳透 鏡將由投影機照射之光線作爲大致射出並行光之光學配置 ，藉雙凸透鏡將該射出光沿畫面之水平方向適度擴散，藉 擴散劑將水平視角朝畫面之垂直方向來擴散光線，藉此， 能得到垂直視角。 又，將微透鏡陣列片（係透鏡片不使用擴散劑，能同時 得到水平視角和垂直視角）與雙凸透鏡加以替換配置，來廢 止/減量擴散劑，藉此，能得到更鮮明、淸晰畫質之透過型 投影幕也係周知。 又，採用以將各柱面透鏡之長度方向係直行的方式來 積層2層之雙凸透鏡層，或是當在一個基材層之雙面，分 別排列複數個柱面透鏡時，使各柱面透鏡之長度方向設成 正交之方法也係周知。 而且，在構成這種雙凸透鏡之各個柱面透鏡之聚光部 分，或是在構成微透鏡陣列片之各個微透鏡之聚光部分， 設置具有開口部之遮光層，來提高投影幕之S/N比之構成 也係周知。 又，按照這些透過型投影幕之用途，亦有在最外面等 ，設置硬塗布層和抗反射膜層（AR層）。 200304579 在使用習知之雙凸透鏡片或微透鏡陣列片而成之透過 型投影幕方面，爲了進行水平方向及垂直方向之視角控制 ，因必須組合雙凸透鏡層和擴散層，或在微透鏡陣列要求 需要以上之廣視角，故產生光被擴散層吸收、因白光散射 造成畫質惡化、因廣擴散造成降低投影幕增益等缺點。 又，採用以將各柱面透鏡之長度方向係直行的方式來 積層2層之雙凸層，或是當在一個基材層之雙面，分別排 列複數個柱面透鏡時，使各柱面透鏡之長度方向設成正交 ，藉此來進行控制水平方向及垂直方向視角之方法也被加 ® 以考慮，惟實質上，構成柱面透鏡之材料變成2倍，且微 細透鏡之加工也必須進行2次，故也有材料成本、加工成 本變高之問題。 又，至於在同一平面上，以使2組雙凸透鏡直行的方 式配設而成之構造之投影幕，因其2組雙凸透鏡係彼此重 疊之構造，故只要變更一方之雙凸透鏡，則另一方之雙凸 透鏡之光學特性亦隨之變化，不能完全獨立進行視角之控 制。因此，其視角之控制範圍受到限制，在實用上不佳。 * 又，爲了使用微透鏡陣列來作爲透過型投影幕，雖需 要適合此之尺寸，例如，對角50吋之大面積之製作，但此 時，爲了得到廣視角，則需要單元透鏡之直徑之大致一半 左右之透鏡厚度（折射面之厚度），就其成形形狀之深度而言 ，要與畫面之大小並存係極爲困難。因此，若係小面積的 話，即使能實現所需之光學性能，就加工上之問題而言， 其大面積化極爲困難。 11 200304579 【發明內容】 本發明，有鑑於以上之情況，其目的係提供一種微透 鏡片，藉由1片透鏡片之透鏡功能，不僅能控制水平方向 ，而且能控制遍及射出方向360°之光擴散性，不必大量使 用光擴散劑，適用於由2片透鏡片（與菲涅耳透鏡片組合）所 構成之背面型投影幕之製造，在觀賞高解析度之畫質上， 能用高精細之間距來排列單元透鏡群。 又，本發明之目的係提供一種微透鏡片，特別係針對 透過型投影幕（由與菲涅耳透鏡片組合而成之2片透鏡片所 ® 構成）用之透鏡片，在微透鏡片中，較佳係用200 /zm以下 之高精細間距來並設單元透鏡群，能控制藉由透鏡部之顯 示光之射出方向（範圍）使成爲廣視角。 又，本發明進一步之目的係提供一種微透鏡片，除了 在上述微透鏡片之透鏡部相反側，形成遮光率高（75%以上） 之黑基質，也容易形成開口部/遮光部之邊界鮮明之高精細 之黑基質。 又，本發明係容易用大面積來提供吸光少，增益降低 ® 少’控制白色散射，使用充分光學特性之微透鏡而成之投 影幕’來作爲螢幕。 此外，本發明係提供使用材料成本、加工成本等皆價 廉之微透鏡而成之投影幕。 本發明之第1形態係一種微透鏡片，在基板之至少單 面具有微透鏡陣列部，該微透鏡陣列部係將單元透鏡排列 成大致2維矩陣狀而成，其特徵在於： 12 200304579 該微透鏡陣列部係只形成在基板之單面，其包含具有 非球面形狀曲面之單元透鏡，相鄰之單元透鏡彼此間之排 列間距爲200 // m以下。 至於用高精細間距來排列單元透鏡群，較佳係前述微 透鏡陣列部使用放射線硬化型樹脂來成型。 在這種發明形態中，也可係一種微透鏡片，在基板之 至少單面具有微透鏡陣列部，該微透鏡陣列部係將單元透 鏡排列成大致2維矩陣狀而成，其特徵在於： 該微透鏡陣列部，係將放射線硬化型樹脂之反應硬化 物聚合並接著在基板之單面而成，其包含具有非球面形狀 曲面之單元透鏡，單元透鏡之排列間距爲l〇〇//m以下。 該微透鏡陣列部，亦可僅以具有球面形狀曲面之單元 透鏡來構成。 單元透鏡之排列也可係任意之排列，也可係設成棋盤 格子狀之矩陣排列，也可係使單元透鏡間之距離相等之三 角形配置，或用這種三角形配置把單元透鏡領域之形狀作 成6角形之蜂巢配置。且也可用稿紙格狀排列，構成透鏡 陣列部之第η列和第n+1列（η係1以上之整數）也可係位移 半間距之排列。單元透鏡領域之形狀也可係矩形、三角形 等形狀。相鄰之單元透鏡領域所形成之三角形有正三角形 之情形與不是正三角形之情形，藉由這些之相異，能使朝 向水平、垂直方向之光之擴散特性相異。 就背面型投影幕而言，爲了提高視覺之顯示影像之對 比，較佳之構成係在基板之微透鏡陣列部相反側之表面， 200304579 將遮光層形成在對應於各單元透鏡之非聚光部處。 本發明之第2形態係一種微透鏡片，在基板之至少單 面具有微透鏡陣列部，該微透鏡陣列部係將單元透鏡排列 成大致2維矩陣狀而成，其特徵在於： 各個單元透鏡徑及其排列間距爲200/zm以下，各單元 透鏡之光線射出角度之範圍相對於微透鏡片主平面之法線 爲±30°以上，且將各單元透鏡所產生之橫向球面像差之 範圍設計成，相對於透鏡徑爲〇%<橫向球面像差S 50%。 本發明之第3形態係一種投影幕，其係使用微透鏡片 ® 而成者，該微透鏡片係在透光性片之單面上，具有將單元 透鏡排列成大致2維矩陣狀而成之微透鏡陣列部，其特徵 在於： 在由複曲面所構成之該透光性片之單面（單元透鏡之特 定方向之截面形狀之曲率較與該特定方向正交之方向之截 面形狀的曲率小，且把這些曲率作成連續面而構成複曲面） 上，形成將該單元透鏡排列成大致2維矩陣狀而成之微透 鏡陣列部；在該透光性片之微透鏡陣列部相反側之表面形 ® 成遮光層，該遮光層具有光軸與單元透鏡群一致之開口部 〇 本發明之第4形態係一種投影幕，其係使用第1形態 之微透鏡片而成者，其特徵在於： 在該透光性片之單面，將該單元透鏡排列成大致2維 矩陣狀而形成微透鏡陣列部時，各單元透鏡係排列成使曲 率之方向一致。 14 200304579 本發明之第5形態係在第2形態之投影幕，其中，該 複曲面係設成，相對於特定方向截面之曲率部厚度之與該 方向正交方向之截面曲率部厚度之比値，即透鏡厚度之比 爲2/3以下。 本發明之第6形態係一種投影幕，其係使用第1形態 之微透鏡片而成者，其中，該複曲面係設成，相對於水平 方向截面之曲率部厚度之垂直方向截面之曲率部厚度之比 値，即透鏡厚度（lens sag)之比爲2/3以下。 本發明之第7形態係一種投影幕，其係使用第1形態 之微透鏡片而成者，在用來作爲透過型投影幕時，該微透 鏡陣列部係形成在成爲入射側（投影機側）之透光性片之單面 〇 本發明之第8形態係在前述形態中之任一投影幕，其 中，該遮光層，係在該透光性片之透鏡部相反側表面所形 成的感光性樹脂層表面，藉由通過微透鏡陣列部之曝光而 形成於未聚光之非聚光領域，且該感光性樹脂層或形成於 其表面之層，係較透光性片之折射率爲低之透鏡基板。 本發明之第9形態，當使用第1形態之微透鏡片之投 影幕來作爲透過型投影幕時，在入射側（投影機側），在單面 上進一步具備同心圓狀環帶構造之菲涅耳透鏡。 【實施方式】 在針對發明之實施例加以說明前，此處，針對對應單 元透鏡形狀之聚光特性和橫向球面像差加以說明。 第3圖係表示單元透鏡爲球面形狀情形之光程之截面 15 200304579 圖（第3 A圖）和表示橫向球面像差之圖形（第3B圖）。第4A 圖係表示單元透鏡爲本發明所限定之非球面形狀之情形之 光程之截面圖（4 A)和表示橫向球面像差之圖形（第4B圖）。 至於第3A圖，從該圖之左側射入到單位透鏡10之平 行光線，係在射入到球面形狀之單元透鏡表面後，受到折 射，在該圖之右側，聚集焦點進行聚光後，在該圖，上下 擴散射出。 此時，藉由球面像差，射入到單元透鏡中心部之光線 焦點變長（在第3A圖，位於右側），射入到單元透鏡端部之 光線焦點變短（在第3A圖，位於左側）。這種像差稱爲縱球 面像差。 另一方面，藉由球面像差，當單元透鏡之中心部爲 y=〇，設定橫軸（PY)，離射出光線與射出面相交位置之光軸 之距離爲△ y(y=0時，△ y=〇)，設定縱軸（EY)，加以繪圖的 話，則成爲表示橫向球面像差之圖形：第3A圖。 第4A、4B圖係球面像差少之單元透鏡形狀之情形。 如第4A圖所示，從單元透鏡之中心部到端部，其焦點大略 一致（縱球面像差少）。對應第4A圖，第4B圖係表示EY 之變動小，橫向球面像差少。 第6圖係表示橫向球面像差少之本發明之單元透鏡形 狀之截面形狀一例之曲線。 又，本發明之微透鏡片之用途係未限於透過型投影幕 者，即使是反射型投影幕，或如透過型/反射型投影幕般， 不僅是大尺寸（30吋以上），而且在備有背光等之內裝光源 16 200304579 之顯示器中，也可適用作爲導光體，用以狴制使來自前述 光源之照明光在顯示畫面內成爲均一之亮度及/或均一之射 出方向。 (作用） 當藉由對應單元透鏡形狀之光學特性來控制顯示光之 射出方向（範圍）時，背面型投影幕之情形，較佳係對光軸（ 對投影幕主面之法線方向）擴散，不依存擴散劑來擴散視角 ，不必使用大量光擴散劑，不導致提高投影幕成本。 本發明係對光軸，將各個透鏡之光線射出角度設定在 ® ±30°以上，藉此針對透過型投影幕，能得到所需之視角 特性，且能進一步期待以下作用之效果。 (提高BM率） 如上述，藉由自對準方式，在微透鏡片上之微細透鏡 ，能用射入平行光線時之聚光圖案，來形成BM，但若依具 有本發明之橫向球面像差之微細單元透鏡的話，則能將該 開口部面積縮到極小。 第7圖係表示單元透鏡用本發明限定之非球面形狀情 ® 形之BM面之曝光分布例之圖，聚光部係脈衝波狀之陡峭 形狀，故聚光部和非聚光部之邊界係明確，當藉由自對準 方式來形成BM時，遮光層（根據上述之感光性黏著劑之黏 著部/非黏著部）之形成部/非形成部係易於明確，容易形成 鮮明之遮光圖案。藉此，能得到具有高遮光率（75%以上）之 BM ’容易得到能顯示高對比影像之投影幕。 當把形成BM之表面（自對準方式之情形，指感光材料 17 200304579 之表面）與透鏡片基材兩者之邊界定義爲「成像面」時，較 佳係將橫向球面像差之變動範圍設定在單元透鏡徑之50% 以下，藉此能將BM面積率（遮光率）形成在75%以上，進一 步，將橫向球面像差之變動範圍設定在單元透鏡徑之31% 以下，藉此也能將BM面積率（遮光率）設定在90%以上，能 與對比一起，大幅提高S/N。 (提高良率） 當藉由自對準方式來形成BM時，因球面像差少，能 提高在焦點之聚光，故能提高曝光部之照度，提高對外來 光（通過單元透鏡所射出之非平行光）之S/N。其結果，能得 到不易受亂射影響而具有正確遮光圖案之透鏡片。 又，就感光材料層而言，設置較透鏡片爲低折射率之 層，調節其厚度，藉此能容易調整BM之精銳度。 以下，參照圖面，將本發明之實施例加以說明。 (第1實施例） 第12圖係表示液晶背面型投影電視之槪略構成之截面 圖。標號31係表示光源，32係表示光學機構部，33係表 示液晶面板，34係表示第1反射鏡，35係表示投射透鏡， 36係表示第2反射鏡，37係表示投影幕。第13圖係在投 影幕37，從上方看A - A截面之截面圖。在第13圖中，標 號38係表示菲涅耳透鏡，39係表示微透鏡，40係表示黑 基質部，41係表示保護層，42係表示硬化層部。 第ΙΑ、1B圖係表示微透鏡片1〇之截面圖。 在基板11 一方之表面，聚合並接著由放射線硬化型樹 200304579 脂之反應硬化物所構成之微透鏡陣列部12，微透鏡陣列部 12，係將具有非球面形狀之曲面之單元透鏡13以200 // m 以下（較佳係在l〇〇//m以下）之間距排列之構成。 在第1A圖中，相鄰之單元透鏡13彼此間係連接之狀 態，如第1B圖所示，相鄰之單元透鏡13彼此間係也可離 間。 當不要求以100// m以下之間距來排列單元透鏡13成 爲高精細化時，微透鏡陣列部12不必使用放射線硬化型樹 脂之反應硬化物來形成，也可對熱可塑性樹脂片表面，藉 由衝壓成形等來加以形成。 第2A〜2D圖係表示第1圖之微透鏡片10之俯視圖。 單元透鏡13係在基板11之表面，用200 //m以下之間距排 列成大致矩陣狀，其排列方法不受限制，即使係第2A圖所 示之整齊棋盤格子狀之矩陣排列、第2B、2C圖所示之三角 形排列、以第2D圖所示之六角形之單元透鏡之蜂巢狀排列 也可。 在該圖中，所謂相鄰之單元透鏡領域係表示以邊來連 接單元透鏡彼此間之情形者。 又，本發明所限定之單元透鏡，在第2A、2C圖中係 矩形，在第2B圖中係三角形，在第2D圖中係六角形，在 第2A圖中係在單元透鏡內具有用圓形表示之透鏡部（曲率） 之構成，由矩形、三角形、六角形等之形狀所構成之單元 透鏡內全體也可係具有透鏡部（曲率）之構成。所謂相鄰之單 元透鏡，在第2圖係指單元透鏡以邊來連接之情形，所謂 19 200304579 單元透鏡彼此間之排列間矩係指單元透鏡中心之離間距離 0 第2A圖（正方形）、第2B圖（正三方形）、第2D圖（正 六方形）之情形，相鄰之單元透鏡彼此間之排列間距係等間 隔，在第2C圖（長方形）之情形’第η列間之單元透鏡之排 列間距、和第η列與第η+1列間之單元透鏡之排列間距係 不同。 又，第2Α圖所示之排列之情形，係如第1圖所示，假 設相鄰之單元透鏡13彼此間連接之情形和離間之情形。 至於第2Β、2C、2D圖所示之排列，在單元透鏡13之 配置間距（假設爲l〇〇#m)以上，會產生精細之週期性（在第 2C圖之例中，藉由週期a和週期b之組合所產生之新的 100//m間距之週期），藉此能減低與來自投影機之投影像 素之間距比所造成之波紋（moire)，進一步具有優越性。 當製造這種微透鏡片10時，在製作成形用之衝模 (stamper)上，係採用衝壓成形和擠壓成形，或藉由2P法 (Photo-Polymer 法）來成形。 上述衝模係微透鏡片10之凹模型（即，單元透鏡部係 成爲凹部之表面形狀），除了使用在金屬層之表面，機械性 地雕刻（或用化學腐蝕）前述凹部等手法外，亦可使用雷射加 工來雕刻前述凹部等之手法。 在任一手法中’當然係必須能正確加工單元透鏡之曲 面形狀，依目的（精細度）來選擇手法。 又’從透鏡頂部起到谷部分位置（從基材表面起之距離） 200304579 係依照單元透鏡之曲面形狀來決定。單元透鏡係正方形和 正六角形，旋轉對稱形狀之透鏡之情形，從頂部起到谷部 分之長度（高度）在單元透鏡之周邊部相異。 單元透鏡之曲面形狀無論球面或非球面皆可，又，爲 了能控制使水平方向和垂直方向之擴散特性不同，必需嚴 密控制前述凹部之形狀。 又，當在成爲微透鏡片10之基板11之透鏡部相反側 之平坦面形成遮光層時，較佳係在前述平坦面全面形成感 光層（藉由感光來使黏著性消失之既知材料）後，從微透鏡陣 列側進行曝光，藉此使照射聚光部部分之感光層變性，在 對應於非聚光部之部分，使油墨和調色劑附著之手法（所謂 藉由透鏡本身之自對準之周知手法）係將遮光層形成在正確 之位置上（未圖示）。 (第2實施例） 第5圖係表示本發明之微透鏡片101之一例之截面圖 〇 在透明支持體103之單面，藉由放射線硬化性樹脂之 硬化物，形成透鏡部（單元透鏡群）1〇2，在透明支持體103 之相反側之平坦面，在相當於各單元透鏡之非聚光部之位 置，透過正型感光性黏著層104形成具有點狀之開口之遮 光圖案（BM = Black Matrix)105。 在透明支持體103中，列舉有聚對苯二甲酸乙二醇酯 (PET)、聚碳酸酯（PC)等。 單元透鏡徑及其並設之間距，在適合觀賞高精細影像 200304579 之投影幕上，較佳係在200 // m以下。 這種精細間距化係能藉由放射性硬化性樹脂之硬化物 ，用2P法（Photo-Polymer法）來加以成形。 第5圖之例，係在折射率1.50，厚度75// m之透明支 持體103之單面，採用2P法，藉由放射性硬化性樹脂之硬 化物來形成非球面透鏡形狀，單元透鏡徑爲80//m之透鏡 部。 第5圖之情形，橫向球面像差之最大寬度爲6//m(相 對於透鏡徑，爲7.5%)，能用92.5%之遮光率來形成BM。 即使係同一材料和尺寸，在單元透鏡形狀爲球面之情 形，橫向球面像差之最大寬度爲30#m(相對於透鏡徑，爲 37.5%)，可形成BM遮光率最大會g到62.5%。 接合1片或複數片上述之微透鏡片，藉此能適用在畫 面尺寸爲30吋以上之背面投影式顯示裝置，能觀賞對比高 ，視野廣之影像。 微透鏡片之情形，與具有柱面透鏡群之雙凸透鏡片相 較，透鏡片之接合邊界不明顯，在大畫面化方面弊害少。 又，在上述中，若在影像光源之投影機側配置菲涅耳 透鏡片的話，則對微透鏡片射入平行光時，能縮短投影機 和投影幕之距離，不僅能將顯示裝置之深度小型化，而且 ，只在需要範圍射出高亮度之顯示影像光。 又，在上述中，也可將由分散光擴散劑所構成之光擴 散層配置在菲涅耳片側及/或微透鏡片之任一位置。 就此處所使用之擴散劑而言，較佳係在無機系材料方 22 200304579 面，使用矽、鋁、鈣，或含有這些氧化物之無機質粉末和 玻璃細珠，或在有機系材料方面，使用丙烯酸系樹脂、苯 乙烯系樹脂、聚碳酸酯系樹脂、由丙烯酸系/苯乙烯系共聚 樹脂等所構成之微粒子。 當選擇光擴散劑時，必須考慮與黏合劑樹脂之折射率 差等光學性質、表面之光澤、當作光擴散基材或光擴散油 墨來進行成形時之分散性、及成形時之脆性等。平均粒徑 爲5//m以上，較佳係5〜20//m，更佳係5〜ΙΟ/zm程度 者較適合。 同時使用光擴散層，藉此在視野之控制上，即使從正 面離開之觀賞方向，亮度也能穩定地降低，並且，不僅在 藉由微透鏡陣列之凹凸（粗糙面）之成像，亦使影像光成像之 作用提高。 單元透鏡越微細，因微透鏡片之透鏡部表面係與粗糙 面具有同樣功能，故對使用光擴散劑之光擴散層之依存度 變低，但當僅藉由前述透鏡部表面來形成之成像及光擴散 性不充分之情形，則倂用前述光擴散層。 又，就放映幕而言，不僅背面投影型，亦可接合1片 或複數片上述微透鏡片，藉此，畫面尺寸也能適用在30吋 以上之前面投影式顯示裝置。 當用來作爲反射型投影幕時，係在微透鏡片之透鏡部 相反側全面形成光反射層。 而且，上述微透鏡片也能應用作爲導光體，用以將來 自光源之照明光，在顯示畫面內控制成均一之亮度及/或均 23 200304579 一之射出方向）。 就這種顯示器而言，以備有背光之液晶顯示裝置（監視 器或可攜式終端機等）爲代表。 (第3實施例） 以下，針對作爲本發明一實施例之投影幕之實施例， 根據圖面詳細加以說明。 第8A、8B圖係本發明之投影幕所使用之微透鏡片之 單元透鏡之槪略圖。第9圖係構成本發明之投影幕所使用 之微透鏡陣列片之單元透鏡之立體圖。第10圖係構成本發 春 明之投影幕所使用之微透鏡陣列片之單元透鏡之垂直方向 截面圖。第11圖係構成本發明之投影幕所使用之微透鏡陣 列片之單元透鏡之水平方向截面圖。又，這些圖所示之透 鏡陣列片，實際上係進行透鏡形狀之設計，根據該設計所 作成之形狀圖。 在第8B圖，透鏡片全體之厚度（從反透鏡面之平坦面 到透鏡頂部之距離）係一樣，但旋轉對稱形狀之複曲面形狀 之單元透鏡之情形，從透鏡頂部到谷部分之距離即使在同 * 一單元透鏡內，在A— A’截面之D1和在B — B’截面之D2 變成相異。 這種微透鏡片之主要特徵在於構成透鏡陣列層之單元 透鏡之形狀。這種透鏡陣列層係由板狀基材層、設置在此 面之透鏡層所構成。 構成這些透鏡陣列之單元透鏡係非球面形狀，而且， 相對於透鏡軸，具有非旋轉對稱之3維幾何學形狀。在該 24 200304579 截面形狀中，藉由該截面之截取法，不僅包含球面，而且 包含非球面形狀（含有橢圓面、拋物面和高次項）。 當採用此種非球面、非旋轉對稱形狀之透鏡時’利用 光線射出時之折射解的差異而對單元透鏡大致平行射入之 射入光（3)，藉由射入面（1)，對應於該射入位置而折射，結 果，由於對與光軸正交的平面上之正交座標軸（相對於垂直 配置之螢幕，相當於垂直方向與水平方向），能具有各個不 同光線的折射率，故可獲得按照目的之配光特性（參考第10 、11 圖）。 具體而言，如第10、11圖所示，顯示射出光（4)之聚光 位置會沿厚度方向不同之現象，此時，光線之射出角度即 相當於配光角度特性。 就透鏡陣列層之材料而言，係玻璃、塑膠等透明之材 料，只要是光學用構件所使用之材料並無特別限制，若考 慮生產效率等的話，較佳係使用塑膠。 就塑膠原料而言，例如，有聚甲基丙烯酸甲酯等丙烯 酸系樹脂、聚碳酸酯樹脂、丙烯酸-苯乙烯共聚體樹脂、苯 乙烯系樹脂、聚氯乙烯樹脂等。 又，因能進行精細間距之微細加工，故就透鏡層之材 料而言，較佳係使用紫外線硬化型樹脂或電子線硬化型樹 脂等之放射線硬化型樹脂。就放射線硬化型樹脂而言，例 如’能使用氨基甲酸乙酯（偏）丙烯酸酯及/或在環氧（偏）丙 烯酸酯低聚物中添加反應稀釋劑、光聚合引發劑、光增感 劑等之組成物等。就聚氨基甲酸（偏）低聚物而言，雖沒有特 25 200304579 別限定，但例如，能使乙二醇、1，4 丁二醇、新戊二醇、聚 己酸內酯聚醇、聚酯聚醇、聚碳酸酯二醇、聚四甲二醇等 之聚醇類，和六甲撐二異氰酸酯、異佛爾酮二異氰酸酯、 甲苯撐二異氰酸酯、苯二甲異氰酸酯等之聚異氰酸酯類反 應來得到。就環氧（偏）丙烯酸酯低聚物而言，雖沒有特別限 定，但例如，能使雙酚A型環氧樹脂、雙酚F型環氧樹脂 、酚醛型環氧樹脂、雙酚A型環氧丙烷附加物之末端縮水 甘油醚、芴環氧樹脂等之環氧樹脂類和（偏）丙烯酸反應能得 到。 透鏡陣列層，例如能以如下方式加以製造。在由塑膠 所構成之基材層上，以未硬化之狀態來塗布放射線硬化型 樹脂，在基材層表面，將成形用衝模（stamper)加以擠壓來 進行壓模，並且，照射既定之放射線使其硬化，藉此，形 成透鏡層。 前述成形用之衝模，例如，能以如下方式來形成透鏡 層。在使用光微影技術之手法，係將單元透鏡之斷層形狀 加以圖案化而成之複數個遮罩，使用該遮罩依序將矽晶圓 進行曝光、RIE等之異向性蝕刻，在其深度方向依序重複 圖案化，能得到具有既定設計形狀之成形用衝模。 如此，透鏡陣列層係能使用與習知之雙凸透鏡之製造 等所使用之方法同樣之方法，來進行製造。 感光性樹脂層和遮光層能以如下方式加以製造。實際 上，係與用來作爲投影幕之狀態同樣，將菲涅耳透鏡加以 平行配置，當透過該菲涅耳透鏡，從透鏡陣列片之透鏡層 26 200304579 側照射光線時，則透過透鏡陣列層被曝光部分之感光性樹 脂層產生變性，使黏著性消失。其次，當對該感光性樹脂 層壓接轉印薄膜（含有碳黑等黑色之轉印層），則在具有黏性 層之未曝光部分，選擇性地轉移轉印層，而形成遮光層。 當形成遮光層時，雖對應藉由複曲面微透鏡來使光線 聚光所形成之線段狀之成像圖案，但因該成像位置大致上 反應複曲面微透鏡之非點像差，故在光軸方向（厚度方向）， 最大產生2處。在該2處焦點（在幾何光學上稱爲弧矢焦點 和子午線焦點）中，調整用以形成透鏡片之最佳位置來挾入 ® 低折射率層（或以此方式來設計透鏡），在該位置設置黑色 之遮光層，藉此能得到更高比例之BM圖案。 此處，使用低折射率層係因該折射力弱，故能增大對 厚度所取之公差，能提高其加工性之故。 而且，在該遮光層上可按照需要來設置黏著劑層、擴 散層、及硬化層等，藉此能作爲透鏡陣列片。 這樣一來，在透鏡陣列片上，適當設計一個複曲面透 鏡陣列之形狀，藉此針對透過該透鏡陣列層之光線，能控 * 制垂直方向和水平方向兩者之配光特性（視角），特別是，將 該比例設定在2/3以下，藉此，可作爲投影幕所適合之垂 直/水平配光特性之分配，能得到作爲投影幕較佳之特性。 進而，與使用二層之透鏡陣列層、在基材層之雙面形 成透鏡層之情形相較，能降低材料成本、加工成本。 又，將擴散層加以簡化，能減少擴散層之吸光及增益 之降低。其結果，能控制擴散層所引起之白色散射現象， 27 200304579 能實現高的S/Ν比。 進而，施加菲涅耳透鏡，藉此，能縮短離投影機之投 射距離，使這些功能並存，藉此，能得到優異之投影幕。 又，本發明之透鏡陣列片之各層厚度、透鏡層之間距 等係不特別限定，能按照用途等來適度加以變更。 [實驗例] 以下，根據實驗例，進一步將本發明加以具體說明。 在本實驗例中，設計參數係如以下方式決定，進行其 效果之驗證實驗。 [設計參數] 在透鏡陣列層之基材層，其材料爲聚對苯二甲酸乙二 醇酯（PET)，厚度爲0.075mm。在透鏡陣列層之透鏡層，其 材料爲UV感光性樹脂，透鏡間距爲〇.〇80mm，將透鏡厚 度（透鏡凸出之高度）之大的截面（對應投影幕左右方向）作成 橢圓，將透鏡厚度（sag)小之截面作成球面，將其厚度量之 比作成2 : 1之複曲面形狀。在感光性樹脂層，係使用厚度 爲20微米之克羅馬林薄膜（商品名：杜邦公司製）。 對該透鏡陣列片之透鏡形成面，從Γ到5°程度，照 射準直（collimate)之平行光，進行感光層之圖案化，轉印厚 度2微米之墨箔（碳黑之轉印箔）作爲遮光層時，能得到具有 開口（對應構成透鏡陣列之微透鏡）之遮光層。 使透鏡陣列面向光源側，將這樣所得到之透鏡陣列片 使用在水平垂直方向之光擴散，能個別得到對應透鏡陣列 形狀之視角，可獲得確認。 28 200304579 產業上之可利用悴 本發明之微透鏡片，係適合藉由與菲涅耳透鏡之組合 而成之2片透鏡片所構成之簡單構成之背面型投影幕之製 造，在觀賞高解析度畫質之影像上不會看到波紋，故極爲 理想。 依本發明之微透鏡片，單元透鏡群能用200 /zm以下之 高精細間距加以排列，並能控制使透鏡部所產生之顯示光 之射出方向（範圍）成爲廣視野。 特別是依本發明，在上述微透鏡片之透鏡部相反側形 成遮光率高（75%)之黑基質上，也容易形成開口部/遮光部 之邊界鮮明之高精細黑基質。 而且，依微透鏡片（具有本發明之投影幕所使用之微透 鏡陣列部），針對透過透鏡陣列層之光線，適當改變單元透 鏡之複曲面形狀，藉此能控制垂直方向和水平方向兩者之 配光特性（視角）。這係表示能主動控制投影幕之光學特性， 在縮短開發期間及削減成本方面具有很大的效果。 又，因能用1片之微透鏡片，自由設定沿垂直方向和 水平方向獨立之視角，故有如下之效果：1)明顯減低加工 成本，2)因能配合既存之材料設定擴散劑之量（效果），故不 需材料之開發/調配，3)因能將光線之吸收（光量損失）抑制 在最低限度，故能因使用微透鏡片而容易獲得鮮明之投影 幕等效果。 又，因能較習知之投影幕減少擴散劑，故能抑制外部 光之反射散射，因提高透明度，故能使遮光層之吸光作用 200304579 增加，能得到習知所沒有之使用提高S/Ν之微透鏡片而成 之投影幕。 【圖式簡單說明】 (一）圖式部分 第ΙΑ、1B圖係表示本發明之微透鏡片一例之截面圖 〇 第2A〜2D圖係表示第1圖之微透鏡片之俯視圖。 第3A圖係表示單元透鏡爲球面形狀情形（習知技術）之 光程之截面圖，第3B圖係表示橫向球面像差之曲線圖。 第4A圖係表示單元透鏡以本發明限定之非球面形狀情 形之光程之截面圖，第4B圖係表示橫向球面像差之曲線圖 〇 第5圖係表示本發明之微透鏡片一例之截面圖。 第6圖係表示本發明之橫向球面像差少之單元透鏡之 截面形狀一例之曲線。 第7圖係表示單元透鏡以本發明限定之非球面形狀情 形之BM面之曝光分布例之曲線圖。 第8A、8B圖係本發明之投影幕所使用之微透鏡片之 單元透鏡之槪略圖。 第9圖係構成本發明之投影幕所使用之微透鏡陣列片 之單元透鏡之立體圖。 第10圖係構成本發明之投影幕所使用之微透鏡陣列片 之單元透鏡之垂直方向截面圖。 第11圖係構成本發明之投影幕所使用之微透鏡陣列片 200304579 之單元透鏡之水平方向截面圖。 第12圖係表示使用本發明之微透鏡片而成之背面型投 影顯示裝置之例。 第13圖係表示使用本發明之微透鏡片而成之投影顯示 裝置之投影幕構造圖。 (二）元件代表符號 10 單元透鏡 11 基板 12 微透鏡陣列部 13 單元透鏡 31 光源 32 光學機構部 33 液晶面板 34 第1反射鏡 35 投射透鏡 36 第2反射鏡 37 投影幕 38 菲涅耳透鏡 39 ’ 微透鏡 40 黑基質 41 保護層 42 硬化層 101 微透鏡片 102 單元透鏡群 200304579 103 透明支持體 104 正型感光性黏著層 105 遮光圖案（BM)"Processing" display devices made of single-tube projectors called reflective light valve methods are being popularized. For these new devices, a better rear-type projection screen is required. The applicant has proposed a rear-type projection screen including lenticular lens sheets exemplified in Japanese Patent Application Laid-Open No. 9-120101, Japanese Patent Application Laid-Open No. 8-269546, and Japanese Patent Application Laid-Open No. 10-83029. These publications are related to the lenticular lens sheet, which must be provided with a light diffusing layer and have cylindrical lens groups arranged in the horizontal direction. Within any cylindrical lens group, they have sufficient light diffusion characteristics. As described above, by controlling the viewing angle (range) of the display light of the conventional lenticular lens sheet, in the lens function, only the horizontal direction can be controlled, and the control in the vertical direction depends on the light diffusion layer. Although the effect of controlling the viewing angle by the lens function is high and fast, the effect of controlling the viewing angle by the light diffusion layer is relatively low and slow. Generally, a light diffusing layer is formed by dispersing and mixing light diffusing fine particles in a resin. Not only is it difficult to select a better combination of the refractive index difference between the light-diffusing fine particles and the aforementioned resin, the particle size (and distribution) of the light-diffusing fine particles, or the suitability for dispersion, but also it is difficult to control only the vertical structure. Directional light diffusivity, horizontal light diffusivity will also be affected. In addition, the so-called improvement of light diffusivity requires the mixing of light diffusing fine particles and 200304579, which causes attenuation of transmitted light (reduction of display brightness) and increases cost. With the lens function, it is expected that the test of light diffusivity in both the horizontal and vertical directions will be performed in accordance with the conventional knowledge. However, in addition to the lens sheet used to control the light diffusivity in the horizontal direction, a test to control the light diffusivity in the vertical direction is added The method of the lens sheet is difficult to adjust the lenses of the two sets of projection screens, resulting in increased costs due to the increase in components. A projection screen composed of a Fresnel lens sheet and a lenticular lens sheet is used instead of the lenticular lens sheet, and a lens sheet that can control the light diffusion by the lens function even in a direction other than horizontal is adopted. Also proposed in Japanese Patent Application Laid-Open No. 2000-131506. According to the proposal of the above publication, a microlens sheet having a microlens array portion is formed. The microlens array portion is formed with optically microlenses that are formed into a concave or convex rotationally symmetric shape, and the shape is formed into a diamond-shaped layer. . In these proposals, it is necessary to provide a diffusion sheet layer on the emission surface side or a sheet in which a diffusing agent is applied inside the microlens array section. As for the above-mentioned new devices, such as XGA, etc., in order to provide high-resolution image quality, the panels (liquid crystal and micro-mirror array 限定 []) that limit the projection image also correspond to the increase in the number of pixels for high-resolution In the projection screen, the arrangement pitch of the cylindrical lens group is also expected to be high. In addition, as the arrangement pitch of the unit lenses is increased, the light-transmitting portion of the light-shielding pattern (BM = Black Matrix) formed on the opposite side of the lens portion is also highly refined, and the light is collected by the micro-lens array portion. The precision required to form sharp openings. 200304579 When a black substrate has a lens sheet with a high-definition lens portion, it uses the light-condensing characteristics of the lens portion itself (for the photosensitive resin layer formed on the lens surface on the opposite side of the lens sheet) to define the correct correspondence to each lens portion. The position of the non-light-condensing part is formed by a so-called self-alignment method. Among the self-alignment methods, there are a wet method (a light-shielding pattern is formed after the exposed photosensitive resin layer is subjected to a development process), and a dry method (the exposed photosensitive resin layer is not subjected to a development process. And colored to form a light-shielding pattern). In the dry method, a photosensitive adhesive is used (corresponding to photosensitive / non-photosensitive, with or without adhesiveness), and coloring is performed according to the presence or absence of adhesiveness. As for the transmissive liquid crystal projection screen, in order to form a black matrix with better shading ratio (empirically, in the contrast of the image, a range of more than 60% is preferred), the light (focusing) position of the lens portion is used, The light-shielding ratio of the pattern to be formed is appropriately set not in the photosensitive resin layer but on the inside of the photosensitive resin layer. When the lens shape is spherical, the focal position (center and end of the lens) will be different due to aberrations. When the light-shielding pattern is formed by the self-alignment method, the denaturation of the photosensitive resin layer cannot be clearly determined. The opening The boundary with the light-shielding part is not easily sharpened. In particular, when high contrast ratios are desired to improve the shading rate, the arrangement pitch of the unit lenses is high-definition. The smaller the unit lenses are, the more difficult it is to form a sharp black matrix, such as the boundary between the tiny openings and the shading portions. Issue 200304579 Also, conventional transmission-type projection screens currently used in commercially available rear-projection televisions and the like are generally provided with a Fresnel lens that forms a concentric convex-concave shape on one side; a lenticular lens. A cylindrical cylindrical lens is arranged in a single direction; and a diffusion layer is provided on one side or one side of the cylindrical lens or on another base material. The elements that make up these transmissive projection screens are firstly configured by Fresnel lenses to illuminate the light emitted by the projector as roughly emitting parallel light. The lenticular lens is used to appropriately diffuse the emitted light in the horizontal direction of the screen. The horizontal viewing angle is used to diffuse the light in the vertical direction of the picture, thereby obtaining the vertical viewing angle. In addition, the microlens array sheet (the lens sheet does not use a diffusing agent, and can obtain horizontal and vertical viewing angles) is replaced with a lenticular lens to dispose of / reduce the diffusing agent, thereby obtaining a sharper and clearer picture. The quality of the transmissive projection screen is also well known. In addition, two lenticular lens layers are laminated in such a way that the length direction of each cylindrical lens is straight, or when a plurality of cylindrical lenses are arranged on both sides of a substrate layer, each cylindrical surface is made A method of setting the length direction of the lens orthogonal is also known. Furthermore, a light-shielding layer having an opening is provided in the light-condensing portion of each cylindrical lens constituting such a lenticular lens, or in the light-concentrating portion of each microlens constituting a microlens array sheet, to improve the S / The composition of the N ratio is also well known. In addition, according to the application of these transmissive projection screens, there are also provided a hard coating layer and an anti-reflection film layer (AR layer) on the outermost surface. 200304579 In the case of a transmissive projection screen using a conventional lenticular lens sheet or a microlens array sheet, in order to control the viewing angle in the horizontal and vertical directions, it is necessary to combine a lenticular lens layer and a diffusion layer. The above wide viewing angles have the disadvantages that light is absorbed by the diffusion layer, image quality is deteriorated due to white light scattering, and projection screen gain is reduced due to wide diffusion. In addition, two lenticular layers are laminated in such a manner that the length direction of each cylindrical lens is straight, or when a plurality of cylindrical lenses are arranged on both sides of a substrate layer, each cylindrical surface is made. The length direction of the lens is set to be orthogonal, and the method of controlling the horizontal and vertical viewing angles is also considered. However, in essence, the material constituting the cylindrical lens is doubled, and the processing of the micro lens must also be performed. Since it is performed twice, there is also a problem that the material cost and the processing cost become high. In addition, as for the projection screen having a structure in which two groups of lenticular lenses are arranged on the same plane, the two groups of lenticular lenses overlap each other, so as long as one of the lenticular lenses is changed, the other The optical characteristics of the lenticular lens change accordingly, and the viewing angle cannot be controlled completely independently. Therefore, the control range of its viewing angle is limited, which is not practical. * Also, in order to use a microlens array as a transmissive projection screen, although a size suitable for this needs to be made, for example, a large area with a diagonal of 50 inches, but at this time, in order to obtain a wide viewing angle, the diameter of the unit lens is required. About half the thickness of the lens (the thickness of the refractive surface), it is extremely difficult to coexist with the size of the screen in terms of the depth of its forming shape. Therefore, if the area is small, even if the required optical performance can be achieved, it is extremely difficult to increase the area in terms of processing problems. 11 200304579 [Summary of the Invention] In view of the above, the present invention aims to provide a microlens sheet. With the lens function of one lens sheet, it can control not only the horizontal direction, but also the light in the 360 ° emission direction. Diffusion, without the need to use a large amount of light diffusing agent, suitable for the manufacture of a rear-type projection screen composed of two lens sheets (combined with Fresnel lens sheets). It can use high-definition for viewing high-resolution image quality. The unit lens groups are arranged at intervals. In addition, the object of the present invention is to provide a microlens sheet, particularly a lens sheet for a transmissive projection screen (consisting of two lens sheets combined with a Fresnel lens sheet) in a microlens sheet. It is preferable to set the unit lens group with a high fine pitch below 200 / zm, which can control the emitting direction (range) of the display light through the lens portion so as to have a wide viewing angle. Furthermore, a further object of the present invention is to provide a microlens sheet, in addition to forming a black matrix with a high light shielding rate (75% or more) on the opposite side of the lens portion of the microlens sheet, it is easy to form a clear boundary between the opening portion and the light shielding portion High fine black matrix. In addition, the present invention makes it easy to provide a large area to provide less light absorption and lower gain ® less control of white scattering and use of a projection screen made of microlenses with sufficient optical characteristics as a screen. In addition, the present invention provides a projection screen made of microlenses that are inexpensive in terms of material cost and processing cost. A first aspect of the present invention is a microlens sheet having a microlens array portion on at least one side of a substrate. The microlens array portion is formed by arranging unit lenses in a substantially two-dimensional matrix, and is characterized by: 12 200304579 The microlens array unit is formed on only one side of the substrate, and includes unit lenses having aspheric curved surfaces. The arrangement distance between adjacent unit lenses is 200 // m or less. As for arranging the unit lens groups with a high fine pitch, it is preferable that the aforementioned microlens array portion is formed using a radiation-hardening resin. In this aspect of the invention, a microlens sheet may also be provided, and a microlens array portion is provided on at least one side of the substrate. The microlens array portion is formed by arranging unit lenses in a substantially two-dimensional matrix, and is characterized by: The microlens array unit is formed by polymerizing a reaction hardened material of a radiation hardening resin and then on one side of a substrate. The microlens array unit includes unit lenses having an aspherical curved surface, and the arrangement distance of unit lenses is 100 // m the following. The microlens array section may be constituted only by a unit lens having a spherical curved surface. The arrangement of the unit lenses can also be arbitrarily arranged, it can also be arranged in a checkerboard-like matrix arrangement, or it can be arranged in a triangle so that the distances between the unit lenses are equal. Hexagonal honeycomb configuration. It can also be arranged in a grid pattern, and the ηth and n + 1th columns (where η is an integer of 1 or more) constituting the lens array section can also be arranged with a displacement of half a pitch. The shape of the unit lens area may be a rectangular shape, a triangular shape, or the like. The triangles formed in the adjacent unit lens fields have regular triangles and cases that are not regular triangles. By these differences, the diffusion characteristics of light in the horizontal and vertical directions can be different. As for the rear-type projection screen, in order to improve the contrast of visual display images, the preferred structure is the surface on the opposite side of the micro lens array portion of the substrate. 200304579 The light-shielding layer is formed at the non-light-concentrating portion corresponding to each unit lens. . A second aspect of the present invention is a microlens sheet having a microlens array portion on at least one side of a substrate. The microlens array portion is formed by arranging unit lenses in a substantially two-dimensional matrix, and is characterized by: each unit lens Diameter and its arrangement interval are 200 / zm or less, the range of the light emitting angle of each unit lens relative to the normal of the main plane of the microlens sheet is ± 30 ° or more, and the range of the transverse spherical aberration generated by each unit lens Designed to be 0% relative to the lens diameter < Transverse spherical aberration S 50%. A third aspect of the present invention is a projection screen made of a microlens sheet®, which is formed on one side of a light-transmitting sheet and has unit lenses arranged in a substantially two-dimensional matrix. The microlens array section is characterized in that a curvature of a cross-sectional shape of a specific direction of a unit lens (a specific direction of a unit lens) is greater than a curvature of a cross-sectional shape of a direction orthogonal to the specific direction of the translucent sheet composed of toric surfaces. The curvature is made as a continuous surface to form a toric surface), and a microlens array portion formed by arranging the unit lenses in a substantially two-dimensional matrix is formed; on the opposite side of the microlens array portion of the translucent sheet The surface is formed into a light-shielding layer, which has an opening portion whose optical axis is consistent with the unit lens group. The fourth aspect of the present invention is a projection screen, which is formed by using the microlens sheet of the first aspect. : When unit lenses are arranged in a substantially two-dimensional matrix to form a microlens array section on one side of the translucent sheet, the unit lenses are arranged so that the directions of curvatures are uniform. 14 200304579 The fifth aspect of the present invention is a projection screen in the second aspect, wherein the toric surface is set as a ratio of a thickness of a curvature portion of a cross section in a specific direction to a thickness of a curvature portion of a cross section in a direction orthogonal to the direction. That is, the ratio of the lens thickness is 2/3 or less. A sixth aspect of the present invention is a projection screen formed by using the microlens sheet of the first aspect, wherein the toric surface is provided as a curvature portion of a vertical cross section with respect to a thickness of a curvature portion of a horizontal cross section. The thickness ratio 値, that is, the ratio of the lens thickness (lens sag) is 2/3 or less. A seventh aspect of the present invention is a projection screen formed by using the microlens sheet of the first aspect. When used as a transmissive projection screen, the microlens array unit is formed on the incident side (projector side). The single side of the translucent sheet. The eighth aspect of the present invention is any one of the aforementioned projection screens, wherein the light-shielding layer is a light-sensitive film formed on the surface on the opposite side of the lens portion of the translucent sheet. The surface of the photosensitive resin layer is formed in a non-light-condensing area by exposure through the microlens array portion, and the refractive index of the photosensitive resin layer or the layer formed on the surface is higher than that of the light-transmitting sheet. Low lens substrate. In the ninth aspect of the present invention, when the projection screen using the microlens sheet of the first aspect is used as a transmissive projection screen, the incident side (projector side) is further provided with a concentric circular ring-shaped structure on one side. Nellen lens. [Embodiment] Before describing the embodiment of the invention, the focusing characteristics and lateral spherical aberration corresponding to the shape of the unit lens will be described here. Fig. 3 is a cross-section showing the optical path of a unit lens with a spherical shape 15 200304579 (Fig. 3A) and a graph showing transverse spherical aberration (Fig. 3B). Fig. 4A is a cross-sectional view (4A) showing the optical path length of a case where the unit lens has an aspheric shape as defined in the present invention, and a graph showing a lateral spherical aberration (Fig. 4B). As for Figure 3A, the parallel rays of light entering the unit lens 10 from the left side of the figure are refracted after entering the surface of the unit lens of a spherical shape. On the right side of the figure, the focus is collected and focused. In this figure, it is diffused and emitted. At this time, with spherical aberration, the focal point of the light incident on the center of the unit lens becomes longer (in Fig. 3A, on the right), and the focal point of the light incident on the end of the unit lens becomes shorter (in Fig. 3A, at Left). This aberration is called longitudinal spherical aberration. On the other hand, with spherical aberration, when the central part of the unit lens is y = 0, the horizontal axis (PY) is set, and the distance from the optical axis where the emitted light intersects the outgoing surface is Δy (when y = 0, △ y = 0), the vertical axis (EY) is set, and when plotted, it becomes a graph showing lateral spherical aberration: FIG. 3A. 4A and 4B show the shape of a unit lens with a small spherical aberration. As shown in Fig. 4A, the focal point is almost the same from the center to the end of the unit lens (less vertical spherical aberration). Corresponding to FIG. 4A and FIG. 4B, the variation of EY is small, and the lateral spherical aberration is small. Fig. 6 is a graph showing an example of a cross-sectional shape of a unit lens shape of the present invention with little lateral spherical aberration. In addition, the application of the microlens sheet of the present invention is not limited to a transmissive projection screen, even a reflective projection screen, or a transmissive / reflective projection screen, not only a large size (30 inches or more), but also in preparation A display with a built-in light source 16 200304579 with a backlight or the like can also be used as a light guide to control the illumination light from the aforementioned light source to have a uniform brightness and / or a uniform emission direction in the display screen. (Function) When the output direction (range) of the display light is controlled by the optical characteristics corresponding to the shape of the lens of the unit, the case of the rear-type projection screen is preferably diffused to the optical axis (to the normal direction of the main surface of the projection screen). It does not rely on a diffusing agent to diffuse the viewing angle, does not need to use a large amount of light diffusing agent, and does not cause an increase in the cost of the projection screen. In the present invention, the light emitting angle of each lens is set to ® ± 30 ° or more with respect to the optical axis, thereby achieving the required viewing angle characteristics for a transmissive projection screen, and the following effects can be further expected. (Improving the BM ratio) As described above, by the self-alignment method, the microlenses on the microlens sheet can form a BM by using a condensing pattern when incident in parallel rays, but if it has the lateral spherical aberration of the present invention With a fine unit lens, the area of this opening can be reduced to a very small size. FIG. 7 is a diagram showing an example of exposure distribution of the aspheric shape of the BM surface defined by the present invention for the unit lens. The light-condensing part is a steep wave-like shape, so the boundary between the light-concentrating part and the non-light-concentrating part. It is clear that when the BM is formed by self-alignment, the formation portion / non-formation portion of the light-shielding layer (adhesive portion / non-adhesive portion according to the above-mentioned photosensitive adhesive) is easy to be identified, and a clear light-shielding pattern is easily formed . As a result, a BM ′ having a high light-shielding rate (more than 75%) can be obtained, and a projection screen capable of displaying a high-contrast image can be easily obtained. When the boundary between the surface forming the BM (in the case of the self-aligning method, the surface of the photosensitive material 17 200304579) and the lens sheet substrate is defined as the "imaging surface", it is preferable to change the range of the lateral spherical aberration. By setting it below 50% of the unit lens diameter, the BM area ratio (light-shielding ratio) can be formed above 75%. Furthermore, the range of lateral spherical aberration can be set below 31% of the unit lens diameter. The BM area ratio (light shielding ratio) can be set to more than 90%, and the S / N can be greatly improved along with the comparison. (Improve Yield) When the BM is formed by self-alignment, the spherical aberration is small, and the light at the focus can be increased. Therefore, the illuminance of the exposure part can be increased, and the external light (the light emitted through the unit lens) can be improved. Non-parallel light). As a result, it is possible to obtain a lens sheet that is not easily affected by stray radiation and has a correct light-shielding pattern. As for the photosensitive material layer, a layer having a lower refractive index than the lens sheet is provided, and the thickness thereof is adjusted, whereby the sharpness of the BM can be easily adjusted. Hereinafter, embodiments of the present invention will be described with reference to the drawings. (First Embodiment) Fig. 12 is a cross-sectional view showing a schematic configuration of a liquid crystal back-type projection television. Reference numeral 31 denotes a light source, 32 denotes an optical mechanism section, 33 denotes a liquid crystal panel, 34 denotes a first mirror, 35 denotes a projection lens, 36 denotes a second mirror, and 37 denotes a projection screen. Figure 13 is a cross-sectional view of the A-A cross section from the top of the projection screen 37. In Fig. 13, reference numeral 38 indicates a Fresnel lens, 39 indicates a microlens, 40 indicates a black matrix portion, 41 indicates a protective layer, and 42 indicates a hardened layer portion. Figures IA and 1B are cross-sectional views showing the microlens sheet 10. On the surface of the substrate 11, a microlens array portion 12 and a microlens array portion 12 composed of a reaction hardened material of a radiation-curable tree 200304579 lipid are polymerized, and the unit lens 13 having an aspherical curved surface is formed by 200 // m or less (preferably below 100 // m). In Fig. 1A, the adjacent unit lenses 13 are connected to each other. As shown in Fig. 1B, the adjacent unit lenses 13 may be separated from each other. When it is not required to arrange the unit lenses 13 at a pitch of 100 // m or less to achieve high definition, the microlens array portion 12 does not need to be formed by using a reaction-hardened product of a radiation-curable resin. It is formed by press forming or the like. 2A to 2D are top views of the microlens sheet 10 shown in FIG. 1. The unit lenses 13 are arranged on the surface of the substrate 11 in a substantially matrix shape with a distance of 200 // m or less. The arrangement method is not limited, even if it is a neat checkerboard-like matrix arrangement shown in FIG. 2A, 2B, A triangular arrangement shown in FIG. 2C and a honeycomb arrangement of hexagonal unit lenses shown in FIG. 2D may be used. In the figure, the so-called adjacent unit lens field indicates a case where unit lenses are connected to each other by edges. In addition, the unit lens defined in the present invention has a rectangular shape in FIGS. 2A and 2C, a triangle in FIG. 2B, a hexagon in FIG. 2D, and a circle in the unit lens in FIG. 2A. The shape of the lens portion (curvature) indicated by the shape may include a lens unit (curvature) as a whole in a unit lens composed of rectangular, triangular, and hexagonal shapes. The so-called adjacent unit lenses in Figure 2 refer to the case where the unit lenses are connected by edges. The so-called 19 200304579 unit lens arrangement moments refer to the distance between the centers of unit lenses. 0 Figure 2A (square), In the case of 2B (rectangular) and 2D (rectangular), the arrangement distance between adjacent unit lenses is equally spaced, and in the case of 2C (rectangular), the arrangement of unit lenses between the nth column The pitch and the arrangement pitch of the unit lenses between the ηth column and the η + 1th column are different. The arrangement shown in Fig. 2A is the case where the adjacent unit lenses 13 are connected to each other and the case where they are separated from each other, as shown in Fig. 1. As for the arrangement shown in Figures 2B, 2C, and 2D, a fine periodicity will be generated above the arrangement pitch of the unit lens 13 (assuming 100 # m) (in the example of Figure 2C, the cycle a The new period of 100 // m pitch generated by the combination with the period b), thereby reducing the moire caused by the distance ratio to the projection pixels from the projector, and further has superiority. When such a microlens sheet 10 is manufactured, stamping and extrusion are used for forming a stamper for forming, or 2P method (Photo-Polymer method) is used for molding. The above-mentioned concave model of the die-type microlens sheet 10 (that is, the surface shape of the unit lens portion becomes the concave portion) can be mechanically engraved (or chemically etched) with the aforementioned concave portion on the surface of the metal layer. The method of engraving the aforementioned recesses and the like using laser processing. In any method, of course, it must be able to correctly process the curved surface shape of the unit lens, and the method is selected according to the purpose (fineness). The position from the top of the lens to the valley (distance from the surface of the substrate) 200304579 is determined according to the curved shape of the unit lens. Unit lenses are square and regular hexagonal, and rotationally symmetric lenses have different lengths (heights) from the top to the valleys at the periphery of the unit lens. The shape of the curved surface of the unit lens may be either spherical or aspherical. In order to control the difference between the horizontal and vertical diffusion characteristics, the shape of the recess must be tightly controlled. When a light-shielding layer is formed on a flat surface on the opposite side to the lens portion of the substrate 11 of the microlens sheet 10, it is preferable to form a photosensitive layer on the flat surface (a known material that causes adhesion to disappear by photosensitivity). The exposure method is from the microlens array side, so that the photosensitive layer of the light-condensing part is denatured, and the method of attaching ink and toner to the part corresponding to the non-light-condensing part (the so-called self-alignment by the lens itself) The standard method is to form the light-shielding layer at the correct position (not shown). (Second Embodiment) FIG. 5 is a cross-sectional view showing an example of the microlens sheet 101 of the present invention. On one side of the transparent support 103, a lens portion (unit lens group) is formed by a hardened material of a radiation-curable resin. ) 102, on a flat surface on the opposite side of the transparent support 103, at a position corresponding to the non-light-condensing portion of each unit lens, a light-shielding pattern (BM with dot-like openings) is formed through the positive photosensitive adhesive layer 104 = Black Matrix) 105. Examples of the transparent support 103 include polyethylene terephthalate (PET) and polycarbonate (PC). The diameter of the unit lens and its parallel distance are preferably below 200 // m on a projection screen suitable for viewing high-definition images 200304579. This fine pitch can be formed by the 2P method (Photo-Polymer method) from the hardened material of the radiocurable resin. The example in Fig. 5 is formed on the single side of a transparent support 103 having a refractive index of 1.50 and a thickness of 75 // m. The 2P method is used to form an aspheric lens shape from a hardened material of a radiocurable resin. The unit lens diameter is 80 // m lens section. In the case of Fig. 5, the maximum width of the lateral spherical aberration is 6 // m (7.5% with respect to the lens diameter), and the BM can be formed with a light shielding rate of 92.5%. Even with the same material and size, the maximum width of the lateral spherical aberration is 30 # m (37.5% relative to the lens diameter) when the shape of the unit lens is spherical, and the maximum BM shading rate will be 62.5%. By combining one or more of the above-mentioned micro-lens sheets, it can be applied to a rear projection display device with a screen size of 30 inches or more, and can watch images with high contrast and wide field of view. In the case of a microlens sheet, compared with a lenticular lens sheet having a cylindrical lens group, the bonding boundary of the lens sheet is not obvious, and there are few disadvantages in terms of large screen. In the above, if a Fresnel lens sheet is arranged on the projector side of the image light source, when the parallel lens is projected into the micro lens sheet, the distance between the projector and the projection screen can be shortened, and not only the depth of the display device can be reduced. It is miniaturized and emits high-intensity display image light only in the required range. Further, in the above, a light-diffusing layer composed of a dispersed light-diffusing agent may be disposed at either the Fresnel sheet side and / or the microlens sheet. As for the diffusing agent used here, it is preferable to use the inorganic material 22 200304579 surface, and use silicon, aluminum, calcium, or inorganic powder and glass beads containing these oxides, or use acrylic material for organic materials Fine particles made of acrylic resin, styrene resin, polycarbonate resin, acrylic / styrene copolymer resin, etc. When selecting a light diffusing agent, it is necessary to consider optical properties such as the refractive index difference from the binder resin, surface gloss, dispersibility during molding as a light diffusing substrate or light diffusing ink, and brittleness during molding. The average particle size is 5 // m or more, preferably 5 to 20 // m, and more preferably 5 to 10 / zm. At the same time, the light diffusion layer is used to control the field of view, and the brightness can be stably reduced even in the viewing direction away from the front, and not only the imaging of the unevenness (rough surface) of the micro lens array, but also the image The role of light imaging is enhanced. The finer the unit lens, the surface of the lens portion of the microlens sheet has the same function as the rough surface, so the dependence on the light diffusion layer using a light diffusing agent becomes lower, but when the imaging is formed only by the surface of the lens portion In the case where the light diffusivity is insufficient, the aforementioned light diffusing layer is used. In addition, as for the projection screen, not only the rear projection type but also one or a plurality of the above-mentioned microlens sheets can be connected, thereby the screen size can be applied to a front projection display device of 30 inches or more. When used as a reflective projection screen, a light reflection layer is formed on the opposite side of the lens portion of the microlens sheet. In addition, the above micro-lens sheet can also be applied as a light guide for controlling the illumination light from the light source in the display screen to have a uniform brightness and / or a uniform emission direction in the display screen). This type of display is typified by a backlit liquid crystal display device (monitor, portable terminal, etc.). (Third Embodiment) Hereinafter, an embodiment of a projection screen as an embodiment of the present invention will be described in detail with reference to the drawings. 8A and 8B are schematic diagrams of unit lenses of a microlens sheet used in the projection screen of the present invention. Fig. 9 is a perspective view of a unit lens constituting a microlens array sheet used in the projection screen of the present invention. Fig. 10 is a vertical sectional view of a unit lens constituting a microlens array sheet used in the projection screen of the present invention. Fig. 11 is a horizontal sectional view of a unit lens constituting a microlens array sheet used in the projection screen of the present invention. In addition, the lens array sheet shown in these figures is actually a lens shape design, and a shape diagram based on the design. In FIG. 8B, the thickness of the entire lens sheet (the distance from the flat surface of the reverse lens surface to the top of the lens) is the same, but in the case of a unit lens with a toric shape with a rotationally symmetric shape, the distance from the top of the lens to the valley is even In the same unit lens, D1 in the AA 'section and D2 in the B-B' section become different. The main feature of this microlens sheet is the shape of the unit lens constituting the lens array layer. This lens array layer is composed of a plate-like substrate layer and a lens layer provided on the surface. The unit lenses constituting these lens arrays have an aspheric shape and have a three-dimensional geometric shape that is not rotationally symmetric with respect to the lens axis. In the 24 200304579 cross-sectional shape, not only the spherical surface but also the aspherical shape (including the elliptical surface, parabolic surface, and higher-order terms) is included by the cutting method of the cross-section. When such an aspheric, non-rotationally symmetric lens is used, the difference between the refraction solution when the light is emitted and the incident light (3) that is approximately parallel to the unit lens, and the incident surface (1) corresponds to Refracting at this incident position, as a result, the refractive index of each light ray can be different for the orthogonal coordinate axis on the plane orthogonal to the optical axis (relative to the vertically arranged screen, corresponding to the vertical and horizontal directions). Therefore, the light distribution characteristics according to the purpose can be obtained (refer to Figures 10 and 11). Specifically, as shown in Figs. 10 and 11, it is shown that the light condensing position of the emitted light (4) is different along the thickness direction. At this time, the angle of light emission is equivalent to the light distribution angle characteristic. As for the material of the lens array layer, transparent materials such as glass and plastic are not particularly limited as long as the materials used for optical members are used. If production efficiency is considered, plastics are preferably used. Examples of plastic materials include acrylic resins such as polymethyl methacrylate, polycarbonate resins, acrylic-styrene copolymer resins, styrene-based resins, and polyvinyl chloride resins. In addition, since fine-pitch fine processing is possible, as the material of the lens layer, a radiation-curable resin such as an ultraviolet-curable resin or an electron-curable resin is preferably used. As for the radiation-hardening resin, for example, urethane (meta) acrylate and / or epoxy (meta) acrylate oligomer can be added with a reaction diluent, a photopolymerization initiator, and a photosensitizer. And other compositions. Polyurethane (meta) oligomers are not limited to 25 200304579, but for example, they can be made of ethylene glycol, 1,4-butanediol, neopentyl glycol, polycaprolactone polyol, Polyols such as polyester polyol, polycarbonate diol, polytetramethylene glycol, etc., react with polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, tolyl diisocyanate, xylylene isocyanate, etc. Come to get. The epoxy (meta) acrylate oligomer is not particularly limited, but, for example, bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, and bisphenol A epoxy resin can be used. Epoxy resins such as terminal glycidyl ethers, epoxy resins such as fluorene epoxy resin, and (meth) acrylic acid can be obtained. The lens array layer can be produced, for example, as follows. The base material layer made of plastic is coated with a radiation-curable resin in an uncured state, and a stamper for molding is pressed on the surface of the base material layer to perform a compression molding, and a predetermined radiation is irradiated. This is hardened, thereby forming a lens layer. In the aforementioned die for forming, for example, the lens layer can be formed in the following manner. In the method of using photolithography technology, a plurality of masks are formed by patterning the sectional shape of the unit lens, and the masks are used to sequentially expose the silicon wafer to anisotropic etching, such as RIE. The patterning in the depth direction is repeated sequentially, and a forming die having a predetermined design shape can be obtained. As described above, the lens array layer can be manufactured by the same method as that used in the conventional manufacturing of lenticular lenses. The photosensitive resin layer and the light-shielding layer can be manufactured as follows. In fact, the Fresnel lens is arranged in parallel as it is used as a projection screen. When the Fresnel lens is transmitted through the lens layer 26 200304579 side of the lens array sheet, light is transmitted through the lens array layer. The exposed portion of the photosensitive resin layer is denatured, causing the adhesiveness to disappear. Next, when a transfer film (a transfer layer containing black such as carbon black) is laminated to the photosensitive resin, the transfer layer is selectively transferred to an unexposed portion having an adhesive layer to form a light-shielding layer. When the light-shielding layer is formed, although it corresponds to a line-shaped imaging pattern formed by toric light focusing by a toric microlens, the imaging position substantially reflects the astigmatism of the toric microlens, so it is on the optical axis Direction (thickness direction), maximum 2 places. In these 2 focal points (referred to as sagittal focal point and meridian focal point in geometric optics), adjust the optimal position to form the lens sheet into the low-refractive index layer (or design the lens in this way). A black light-shielding layer is provided at this position, thereby obtaining a higher proportion of the BM pattern. Here, since the low refractive index layer is used, since the refractive power is weak, the tolerance to the thickness can be increased, and the workability can be improved. In addition, an adhesive layer, a diffusion layer, a hardened layer, and the like can be provided on the light-shielding layer as needed, thereby serving as a lens array sheet. In this way, the shape of a toric lens array is appropriately designed on the lens array sheet, so that the light distribution characteristics (viewing angle) of both the vertical and horizontal directions can be controlled for the light passing through the lens array layer, especially Yes, the ratio is set to less than 2/3, so that it can be used as a distribution of vertical / horizontal light distribution characteristics suitable for a projection screen, and can obtain better characteristics as a projection screen. Furthermore, compared with the case where a two-layer lens array layer is used and a lens layer is formed on both sides of the base material layer, the material cost and processing cost can be reduced. In addition, simplification of the diffusion layer can reduce light absorption and reduction in gain of the diffusion layer. As a result, the white scattering phenomenon caused by the diffusion layer can be controlled, and a high S / N ratio can be achieved. Furthermore, by applying a Fresnel lens, the projection distance from the projector can be shortened, and these functions can be co-existed, whereby an excellent projection screen can be obtained. In addition, the thickness of each layer of the lens array sheet of the present invention, the distance between the lens layers, and the like are not particularly limited, and can be appropriately changed depending on the application and the like. [Experimental Examples] Hereinafter, the present invention will be described in more detail based on experimental examples. In this experimental example, the design parameters were determined in the following manner, and the effect verification experiments were performed. [Design parameters] In the substrate layer of the lens array layer, the material is polyethylene terephthalate (PET) and the thickness is 0.075mm. The lens layer of the lens array layer is made of UV-sensitive resin with a lens pitch of 0.080 mm. A large section (corresponding to the left and right directions of the projection screen) of the lens thickness (the height of the lens projection) is made into an ellipse. The section with a small thickness (sag) is made into a spherical surface, and the ratio of the thickness is made into a toric shape of 2: 1. As the photosensitive resin layer, a 20-micron-thick Cromlin film (trade name: manufactured by DuPont) was used. The lens-forming surface of the lens array sheet was irradiated with collimated parallel light from Γ to 5 °, patterned the photosensitive layer, and transferred an ink foil (carbon black transfer foil) with a thickness of 2 microns. When used as a light-shielding layer, a light-shielding layer having an opening (corresponding to the microlenses constituting the lens array) can be obtained. The lens array is faced to the light source side, and the lens array sheet thus obtained is diffused in the horizontal and vertical directions to obtain the viewing angle corresponding to the shape of the lens array, which can be confirmed. 28 200304579 The microlens sheet that can be used in the industry in the present invention is suitable for the manufacture of a simple rear projection screen composed of two lens sheets combined with a Fresnel lens. High-quality images are ideal because they do not see moire. According to the microlens sheet of the present invention, the unit lens group can be arranged with a high fine pitch of 200 / zm or less, and can control the emission direction (range) of the display light generated by the lens portion to a wide field of view. In particular, according to the present invention, a high-definition black matrix with a clear boundary between the opening portion and the light-shielding portion is easily formed on a black matrix having a high light shielding rate (75%) on the opposite side of the lens portion of the microlens sheet. In addition, according to the microlens sheet (having the microlens array portion used in the projection screen of the present invention), the shape of the toric surface of the unit lens is appropriately changed for the light passing through the lens array layer, thereby controlling both the vertical and horizontal directions. Light distribution characteristics (viewing angle). This means that the optical characteristics of the projection screen can be actively controlled, which has a great effect in shortening the development period and reducing costs. In addition, since one micro lens can be used to set independent viewing angles in the vertical and horizontal directions, it has the following effects: 1) significantly reduces processing costs, and 2) can set the amount of diffusing agent with existing materials (Effect), so no development / mixing of materials is needed. 3) Since the absorption of light (loss of light) can be minimized, it is easy to obtain clear projection screens and other effects due to the use of microlens sheets. In addition, because it can reduce the diffusing agent compared with the conventional projection screen, it can suppress the reflection and scattering of external light, and because it improves the transparency, it can increase the light absorption effect of the light-shielding layer 200304579, which can be used to improve the S / N that is not known Projection screen made of micro lens. [Brief description of the drawings] (I) Schematic drawings Figures IA and 1B are cross-sectional views showing an example of the microlens sheet of the present invention. Figures 2A to 2D are plan views showing the microlens sheet of Figure 1. FIG. 3A is a cross-sectional view showing the optical path length of a case where the unit lens has a spherical shape (a conventional technique), and FIG. 3B is a graph showing a lateral spherical aberration. FIG. 4A is a cross-sectional view showing an optical path of a unit lens in an aspherical shape defined by the present invention, and FIG. 4B is a graph showing a lateral spherical aberration. FIG. 5 is a cross-section showing an example of a microlens sheet of the present invention. Illustration. Fig. 6 is a graph showing an example of a cross-sectional shape of a unit lens having a small lateral spherical aberration according to the present invention. Fig. 7 is a graph showing an example of the exposure distribution of the unit lens with the BM surface of the aspheric shape defined in the present invention. 8A and 8B are schematic diagrams of unit lenses of a microlens sheet used in the projection screen of the present invention. Fig. 9 is a perspective view of a unit lens constituting a microlens array sheet used in the projection screen of the present invention. Fig. 10 is a vertical sectional view of a unit lens constituting a microlens array sheet used in the projection screen of the present invention. Fig. 11 is a horizontal sectional view of a unit lens constituting a microlens array sheet 200304579 used in the projection screen of the present invention. Fig. 12 shows an example of a rear-type projection display device using the microlens sheet of the present invention. Fig. 13 is a diagram showing the structure of a projection screen of a projection display device using the microlens sheet of the present invention. (II) Symbols for components 10 Unit lens 11 Substrate 12 Micro lens array section 13 Unit lens 31 Light source 32 Optical mechanism section 33 Liquid crystal panel 34 First reflector 35 Projection lens 36 Second reflector 37 Projection screen 38 Fresnel lens 39 '' Micro lens 40 black matrix 41 protective layer 42 hardened layer 101 micro lens sheet 102 unit lens group 200304579 103 transparent support 104 positive photosensitive adhesive layer 105 light blocking pattern (BM)
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