201030382 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種具有聚光、光擴散、使光線朝法線 方向折射等各種機能，特別是適用於液晶顯示裝置用背光 單元之光學片，及使用其之背光單元。 【先前技術】 液晶顯示裝置，係普遍採用自背面照射液晶層之背光 ® 方式’液晶層之下面側裝有邊光型（側光型）、直下型等之背 光單元。該邊光型之背光單元40, 一般而言係如圖9(a)所 示’具備：作為光源之棒狀燈源41、以端部沿著該燈源41 的方式進行配置的方形板狀之導光板42、積層於該導光板 42表面側之複數片光學片43。該光學片43，係具有折射、 光擴散等特定之光學機能，具體而言係具備以下等之元 件：（1)微透鏡片44，係配設於導光板42之表面側，主要 具有光擴散機能與聚光機能；（2)稜鏡片45，係配設於微透 ^ 鏡片44之表面侧’主要具有朝法線方向侧折射的機能。 以下對該背光單元40之機能加以說明，首先，自燈源 4 1入射至導光板42之光線，被導光板42背面的反射點或 反射片（未圖示）以及各側面所反射，而於導光板42表面出 射。自導光板42出射之光線，入射至微透鏡片44,於表面 所設之微透鏡界面擴散、出射。然後，從微透鏡片44出射 之光線，入射至稜鏡片45,藉由形成於表面上之稜鏡部Μ 而在大致正上方向作為顯示峰值之分布的光線而出射。背 201030382 光單元40,如上所述，係使自燈源41出射之光線藉由光學 片43加以擴散，在大致正上方向顯示出峰值的方式進行折 射’進而照明於上方未圖示之液晶層整面。 - 此外雖未圖示，考量到上述導光板42的導光特性與光 學片43的光學機能等，亦有配設更多微透鏡片與稜鏡片等 之光學片43的背光單元。 上述以往之微透鏡片44, 一般而言係如圖9(b)所示， 於表面具備有由複數個微透鏡所構成之微透鏡陣列47，於 背面具有平面形狀（例如，參考曰本專利特開2〇〇4_ 19ΐ6ιι 號么報等）。设置於上述微透鏡片表面之該微透鏡界面中， 自燈源發射之光線係朝正面侧聚光、擴散、朝法線方向側 變角等。 然而，該微透鏡片之聚光、光擴散、變角等光學機能， 係因表面形狀以及折射率而定，故對於提升機能有一定的 限界特別疋’直下型背光中，光學片的光擴散機能不充 刀的It况下’ 源影像的消去效果較小，故有燈源影像出 二在液晶畫面表面之缺點。因此，以往之背光單元40，儘❹ 管昂貴且操作困難’仍有必要具備複數片之光學片。如上 所述具備複數片之光學片的情形，除了有液晶顯示裝置之 焭度降低之缺點，亦妨礙了背光單元的薄型化。 先前技術文獻 [專利文獻1]日本專利特開2⑽4—191611號公報 【發明内容】 4 201030382 發明所欲解決之課題 本發明有鐘於該等缺點’其目的在於提供一種液晶顯 不裝置用光學片，及使用其之背光單元；該液晶顯示裝置 用光學片，其光學機能，特別是光擴散機能格外優異；該 背光單元，其增進視野角的最佳化、燈源影像的去除、薄 型化等品質的提升。 用以解決課題之手段 用以解決上述課題之發明，係一種液晶顯示裝置用光 學片’其具備： 透明基材層；以及 微透鏡陣列，係由該基材層表面以及背面所形成之複 數個微透鏡所構成。 該液晶顯示裝置用光學片，因不僅於表面，於背面亦 具備微透鏡陣列，故即使於液晶顯示裝置用光學片背面之 界面亦可將來自背光的光線加以折射、擴散等。因此， 參 該液晶顯示裝置用光學片，於表裏兩面之界面可將來自背 先的先線加以折射、擴散’可將光擴散機能等之光學機能 進-步提高。此外，依照該液晶顯示裝置用光學片，藉由 表裏兩面之界面之折射來使光線折射、擴散，故可將^晶 顯示裝置用光學片令光線的損失抑制在最小限 光穿透率。 捉间 透鏡背It微透鏡，可為凹透鏡。藉由背面之微透鏡為凹 自背光的光線會於入射至光學片背面之際， 面光線會朝分散之方向折射、擴散。因此，藉由該液晶顯 5 201030382 不裝置用光學片，可更進— 贽&夕％ '秦# , 步耠同先擴散機能等光學機能。 貪面之微透鏡陣列，較佳為且 微透鏡所構成者。藉由皆而 隨機直徑之由複數個 液透鏡具有隨機的直徑之該 液曰日顯不裝置用光學片，於光 “心μ 於先學片皮面中，來自背光的光 線所折射 '擴散之方向以及角 勒機-w 及再度會呈現隨機分布，故光擴 的去除性。 “的均句性、燈源影像 表面之微透鏡的平均半徑，可為3心以上9〇㈣以 下；背面之微透鏡的平均半徑可為2心以上⑽瓜以下。 藉由該液晶顯示裝置用光學片，因表面以及背面之微透鏡 具有上述範圍的平均半徑，可使光擴散等之光學機能進一 步提升，可簡單且確實地調控該光學機能。 背面之微透鏡的平均半徑，可為表面之微透鏡的平均 半徑的1/12以上1以下。藉由背面與表面之微透鏡的平 均半徑比位於上述範圍之該液晶顯示裝置用光學片，因兩 面之微透鏡的相乘效果’可進一步提升光擴散效果。 基材層與該基材層表面以及背面之微透鏡陣列可為一 體成形。藉由使該光學片如上所述一體成形，於片的内部 不會產生光的折射、散射，而將光線的損失抑制在最小限 度，故可提升光穿透率以及亮度。 至少表面之微透鏡陣列中之微透鏡的配設圖案，較佳 為正三角形格子圖案或隨機圖案。該正三角形格子圖案， 因可將微透鏡更緊密地配設，故該液晶顯示裝置用光學片 的透鏡充塡率可簡單地提升，聚光、光擴散等光學機能會 201030382 格外地提高。此外，藉由以隨機圖案的方式配設微透鏡， 於該液晶顯示裝置用光學片與其他光學構件重合之際可減 低疊紋的產生9 該液晶顯示裝置用光學片，係可藉由擠製片成形法而 形成（該擠製片成形法係使用具有該表面之微透鏡陣列之反 轉形狀之壓紋輥、以及與該壓紋輥平行配置且具有該背面 之微透鏡陣列之反轉形狀之壓紋輥）。藉由該手段，可簡單 且高精度地形成於兩面具有特定之微透鏡陣列之光學片， © 並可簡單地利用同一材質加以一體成形。 因此’在將自燈源發射之光線分散引導至該表面侧之 液晶顯示裝置用背光單元，藉由具備光學機能、特別是光 擴散機能以及其控制機能格外優異之該液晶顯示裝置用光 學片’品質可因亮度的統一化以及高度化而提升。 此處’所謂液晶顯示裝置用光學片之Γ表面」以及「背 面J ，思#曰於液晶顯示裝置之背光單元上具備有通常之液 晶顯示裝置用光學片時，面向表側（液晶層側）之面作為「表 面」；其相對側（導光板側）之面作為「背面」。所謂「微透 鏡」，意指含有凸透鏡以及凹透鏡之概念。所謂「正三角 形格子圖案」，意指表面被區分為同一形狀之正三角形， 於该正二角形之各頂點配設有微透鏡之圖案。 發明效果 “如以上之說明，依據本發明之液晶表示用光學片，其 光學機能、特別是光擴散機能格外優異，並可簡單且確實 地控制該光學機能。此外，使用該液晶顯示裝置用光學片 7 201030382 之背光’可增進視野角的最佳化、燈源影像的去除、薄型 化等品質的提升，以及低成本化。 【實施方式】 以下，一邊參照適當圖式，一邊詳細說明本發明之實 施形態。 圖1之液晶顯示裝置用光學片1，係具備基材層2、於 該基材層2表面所形成之微透鏡陣列3、以及於基材層2背 面所形成之微透鏡陣列4。 基材層2 ’因必須使光線透過’故係由透明、特別是由 無色透明的合成樹脂所形成。作為基材層2所用之合成樹 脂，並無特別限定，例如可列舉聚對苯二甲酸乙二酯、聚 萘二甲酸乙二酯、丙烯酸樹脂、聚碳酸酯、聚苯乙烯、聚 烯烴、乙酸纖維素、耐候性氯乙烯、放射線硬化型樹脂等。 其中，較佳為對於微透鏡陣列3以及4之成形性優異之紫 外線硬化型樹脂、電子線硬化型樹脂等放射線硬化型樹脂 或聚碳酸酯、聚烯烴等熱可塑性樹脂。 基材層2的厚度（平均厚度）並無特別限定，例如為… "m以上則心以下，較佳為35”以上25〇"m以下， 特料5〇/zm以上188心以下。基材層2的厚度若低於上 述範圍’則背光單元等暴露於熱時會容易發生彎曲，而產 =難以使用等缺點。相對地，基材層2的厚度若超出上述 範圍’則有時液晶顯示裝置的亮度會降低，此外背光單元 的厚度會變大而不符合液晶顯示裝置薄型化的需求。 201030382 形成基材層2之聚合物樹脂中亦可含有微小無機充 ，。如上所述藉由於基材層2中含有微小無機充填劑，可 提升基材層2進而液晶顯示裝置用光學片1的耐熱性 為構成該微小無機充塡劑之無機物並無特別限定，、較 無機氧化物。該無機氧化物，係定義為各種含氧金 物，其金屬元素透過主要為與氧原子鍵結而構成3維網: 了構。作為構成無機氧化物之金屬元素，例如較 魯 ⑩ 兀素周期表第2族〜第6族之元素，更佳 ^ ,,,油 又住馬選自兀素周期 表第3族〜第5族之元素。特別是以選自a卜η以及 △之元素較佳，又以金屬元素為以之膠體二氧切 ί It提升效果以及均句分散性方面最適於作為微小無機充 1。此外，微小無機充塡劑的形狀可為球狀、針狀、 狀、鱗片狀、破碎狀等任意的粒子形狀，並無特別限定。 作為微小無機充塡劑之平均粒子徑的下限，較 5nm ’特佳為1Gnm。另—方面，作為微小無機充填劑之平 均粒子徑的上限，較佳為5〇nm，特佳為25·其理由在於， 2小無機充填劑之平均粒子徑若低於上述範圍，則微小並 機充塡劑的表面能量會變高，而容易引起凝集等；相反地， 平均粒子控若超出上述範圍’則因短波長影響而產生白 濁，基材層2的透明性會降低，而影響穿透率。 基㈣2中可含有抗靜電劑。如上所述藉由混 劑之聚合物樹脂來形成基材層2,該液晶顯示裝 不县2片1可表現抗靜電效果，而可防止吸附雜質、或 、、他先學片等重合等因帶有靜電所產生之缺點。此 9 201030382 外’若將抗靜電劑塗佈於表面，則雖會產生表面黏稠或污 /蜀’但如上所述藉由於基材層2中混練抗靜電劑可減低其 弊害。作為§亥抗靜電劑並無特別限定，例如可使用烧基硫 酸鹽、烧基磷酸鹽等陰離子系抗靜電劑；第四銨鹽、咪唑 琳化合物等陽離子系抗靜電劑；聚乙二醇系、聚氧乙稀山 梨糖醇單硬脂酸酯、乙醇胺類等非離子系抗靜電劑、聚丙 烯酸等高分子系抗靜電劑等。其中，較佳為抗靜電效果比 較的大的陽離子系抗靜電劑，少量添加即可發揮抗靜電效 果。 此外，基材層2中可含有紫外線吸收劑。藉由形成含 有上述紫外線吸收劑之基材層2，可賦予該液晶顯示裝置用 光學片1阻隔紫外線的機能，可將來自背光單元之燈源發 射之微量紫外線加以阻隔，防止紫外㈣液晶層的破壞。 亦可使用紫外線安定劑（分子鏈含結合有紫外線安定基 之基材聚合物）’來取代上述紫外線吸收劑，或與紫外線^ 收劑同時使用。藉由該紫外線安^劑，可使紫外線所產生 =由基、活性氧等去活化，以提升紫外線安定性、耐候 性專。作為該紫外線安定劑，可較佳使用#紫外線具有古 :定性之受阻胺(hindered amine)系紫外線安定齊卜此外" 藉由併用紫外線吸收劑與紫外線安定拖丨 &卜線"^劑’可防止紫外線所 劣化以及使耐候性格外地提高。 5所:成透鏡陣列3,係由具有大致相同直徑之多數個微透鏡 微透鏡陣列4，係由|古！^ ^ ^ 宁由具有隨機直控之多數個微透鏡6所 201030382 構成。此外，微透鏡陣列4中之多數個微透鏡6，係以隨機 圖案且相對緻密的方式所形成。 微透鏡陣列3以及4,可與基材層2一體成形，亦可與 基材層2各別地成形。微透鏡陣列3以及4，因必須使光線 透過’故係由透明、特別是由無色透明的合成樹脂所形成， 具體而&可使用與上述基材層2相同之合成樹脂。此外， 作為基材層2,可使用聚對苯二甲酸乙：自旨膜、聚萘二曱酸201030382 VI. Description of the Invention: [Technical Field] The present invention relates to an optical sheet having a function of collecting light, diffusing light, refracting light toward a normal direction, and the like, and particularly, an optical sheet suitable for a backlight unit for a liquid crystal display device. And a backlight unit using the same. [Prior Art] A liquid crystal display device is generally provided with a backlight from a rear surface of a liquid crystal layer. The liquid crystal layer has a backlight unit of a side light type (side light type) or a direct type. The edge type light-emitting backlight unit 40 generally has a square-shaped light source 41 as a light source and a square plate shape in which an end portion is arranged along the light source 41 as shown in FIG. 9(a). The light guide plate 42 and a plurality of optical sheets 43 laminated on the surface side of the light guide plate 42. The optical sheet 43 has specific optical functions such as refraction and light diffusion, and specifically includes the following elements: (1) The lenticular sheet 44 is disposed on the surface side of the light guide plate 42 and mainly has light diffusion. The function and the concentrating function; (2) the cymbal 45, which is disposed on the surface side of the micro-transparent lens 44, mainly has a function of refracting toward the normal side. Hereinafter, the function of the backlight unit 40 will be described. First, the light incident from the light source 41 to the light guide plate 42 is reflected by the reflection point or the reflection sheet (not shown) on the back surface of the light guide plate 42 and the side surfaces. The surface of the light guide plate 42 is emitted. The light emitted from the light guide plate 42 is incident on the lenticular sheet 44, and is diffused and emitted at the interface of the microlens provided on the surface. Then, the light emitted from the lenticular sheet 44 is incident on the cymbal sheet 45, and is emitted as a light beam showing a distribution of peaks in a substantially upper direction by the ridge portion 形成 formed on the surface. In the light source unit 40, as described above, the light emitted from the light source 41 is diffused by the optical sheet 43 and refracted so as to show a peak in a substantially normal direction, thereby illuminating the liquid crystal layer not shown above. The whole face. Further, although not shown, the light guide characteristics of the light guide plate 42 and the optical function of the optical sheet 43 are considered, and a backlight unit in which a plurality of optical sheets 43 such as a lenticular sheet and a cymbal sheet are disposed is also provided. As described above, in the conventional microlens sheet 44, as shown in FIG. 9(b), a microlens array 47 composed of a plurality of microlenses is provided on the surface, and has a planar shape on the back surface (for example, referring to the patent) Special opening 2〇〇4_ 19ΐ6ιι号, newspaper, etc.). In the microlens interface disposed on the surface of the lenticular sheet, the light emitted from the light source is concentrated toward the front side, diffused, and angled toward the normal side. However, the optical functions such as concentrating, diffusing, and variable angle of the lenticular sheet are determined by the surface shape and the refractive index, so that there is a certain limit on the hoisting function. In particular, in the direct-type backlight, the light diffusion of the optical sheet In the case of the function without the knife, the effect of the source image is small, so there is a disadvantage that the light source image is on the surface of the liquid crystal screen. Therefore, in the related art, the backlight unit 40 is expensive and difficult to operate. It is necessary to have a plurality of optical sheets. In the case of the optical sheet having a plurality of sheets as described above, in addition to the disadvantage that the degree of twist of the liquid crystal display device is lowered, the thickness of the backlight unit is hindered. [Patent Document 1] Japanese Laid-Open Patent Publication No. Hei 2 (10) No. 4-191611. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION The present invention has the object of providing such an optical sheet for a liquid crystal display device. And a backlight unit using the same; the optical sheet for a liquid crystal display device is particularly excellent in optical function, particularly a light diffusing device; and the backlight unit improves the viewing angle, removes the light source image, and thins the image. Quality improvement. In order to solve the above problems, an optical sheet for a liquid crystal display device includes: a transparent base material layer; and a microlens array formed of a plurality of surfaces and back surfaces of the base material layer Made up of microlenses. In the optical sheet for a liquid crystal display device, since the microlens array is provided not only on the surface but also on the back surface, the light from the backlight can be refracted and diffused even at the interface on the back surface of the optical sheet for a liquid crystal display device. Therefore, in the optical sheet for a liquid crystal display device, the front line from the back can be refracted and diffused at the interface between the front and the back, and the optical function such as the light diffusing function can be further improved. Further, according to the optical sheet for a liquid crystal display device, light is refracted and diffused by the refraction of the interface between the front and back surfaces, so that the optical sheet can be used to suppress the loss of light to the minimum light transmittance. The inter-lens back It microlens can be a concave lens. When the microlens on the back surface is concave, the light from the backlight will refract and diffuse in the direction of dispersion when incident on the back side of the optical sheet. Therefore, by using the optical sheet for the liquid crystal display 5 201030382, it is possible to further improve the optical functions such as the first diffusion function and the first diffusion function. The greedy microlens array is preferably composed of microlenses. By means of a random diameter of a plurality of liquid lenses having a random diameter, the liquid 曰 显 装置 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学 光学The direction and the angle machine -w and again will be randomly distributed, so the optical expansion is removed. "The average sentence, the average radius of the microlens on the surface of the light source image can be more than 3 hearts and 9 inches (four) or less; The average radius of the microlens may be less than 2 centimeters (10) or less. According to the optical sheet for a liquid crystal display device, since the microlens on the front surface and the back surface have an average radius in the above range, the optical function such as light diffusion can be further improved, and the optical function can be easily and surely adjusted. The average radius of the microlenses on the back surface may be 1/12 or more and 1 or less of the average radius of the microlenses on the surface. The optical sheet for a liquid crystal display device having an average radius ratio of the microlens on the back surface and the surface is in the above range, and the light diffusion effect can be further enhanced by the multiplication effect of the microlenses on both sides. The substrate layer and the microlens array of the surface of the substrate layer and the back surface may be integrally formed. By integrally molding the optical sheet as described above, light refraction and scattering are not generated inside the sheet, and the loss of light is suppressed to a minimum, so that light transmittance and brightness can be improved. The arrangement pattern of the microlenses in at least the surface microlens array is preferably an equilateral triangle lattice pattern or a random pattern. In the regular triangular lattice pattern, since the microlenses can be more closely arranged, the lens filling rate of the optical sheet for a liquid crystal display device can be easily increased, and the optical functions such as condensing and light diffusion can be particularly improved in 201030382. In addition, by arranging the microlenses in a random pattern, the occurrence of the moiré can be reduced when the optical sheet for the liquid crystal display device is overlapped with other optical members. 9 The optical sheet for a liquid crystal display device can be extruded. Formed by a sheet forming method in which an embossing roll having an inverted shape of a microlens array having the surface, and an inverted shape of the microlens array having the back surface arranged in parallel with the embossing roll Embossed roller). By this means, an optical sheet having a specific microlens array on both sides can be formed simply and accurately, and can be integrally formed by simply using the same material. Therefore, the optical unit for liquid crystal display device which is excellent in the optical function, particularly the light diffusing function and the control function thereof, is provided by the backlight unit for liquid crystal display device which is guided by the light source from the light source. Quality can be improved by the uniformity and height of brightness. Here, the "surface of the optical sheet for a liquid crystal display device" and the "back surface J" are provided on the front side (the liquid crystal layer side) when the optical unit for a liquid crystal display device is provided in the backlight unit of the liquid crystal display device. The surface is referred to as "surface"; the surface on the opposite side (light guide side) is referred to as "back surface". The term "microlens" means the concept of a convex lens and a concave lens. The "positive triangular lattice pattern" means an equilateral triangle whose surface is divided into the same shape, and a pattern of microlenses is arranged at each vertex of the regular dimple. Advantageous Effects of Invention As described above, according to the optical sheet for liquid crystal display of the present invention, the optical function, particularly the light diffusing device, can be particularly excellent, and the optical function can be controlled simply and surely. Further, the optical device for the liquid crystal display device is used. The backlight of the sheet 7 201030382 can improve the quality of the viewing angle, improve the quality of the light source image, reduce the thickness, and reduce the cost. [Embodiment] Hereinafter, the present invention will be described in detail with reference to the appropriate drawings. The optical sheet 1 for a liquid crystal display device of FIG. 1 includes a base material layer 2, a microlens array 3 formed on the surface of the base material layer 2, and a microlens array formed on the back surface of the base material layer 2. 4. The base material layer 2' is formed of a transparent, particularly colorless, transparent synthetic resin because it must pass light. The synthetic resin used for the base material layer 2 is not particularly limited, and examples thereof include polyparaphenylene. Ethylene dicarboxylate, polyethylene naphthalate, acrylic resin, polycarbonate, polystyrene, polyolefin, cellulose acetate, weather resistant vinyl chloride, put Among them, a radiation curable resin such as an ultraviolet curable resin or an electron beam curable resin which is excellent in moldability of the microlens arrays 3 and 4, or a thermoplastic resin such as polycarbonate or polyolefin is preferable. The thickness (average thickness) of the base material layer 2 is not particularly limited, and is, for example, "/m or less", preferably 35" or more and 25" or less, and the content is 5 〇/zm or more and 188 or less. When the thickness of the base material layer 2 is lower than the above range, the backlight unit or the like is likely to be bent when exposed to heat, and the production is difficult to use. On the other hand, when the thickness of the base material layer 2 exceeds the above range, the brightness of the liquid crystal display device may be lowered, and the thickness of the backlight unit may become large, which does not conform to the demand for thinning of the liquid crystal display device. 201030382 The polymer resin forming the substrate layer 2 may also contain a minute inorganic charge. As described above, the base material layer 2 and the heat resistance of the optical sheet 1 for a liquid crystal display device are not particularly limited as long as the base material layer 2 contains a fine inorganic filler, and the heat resistance of the optical sheet 1 for a liquid crystal display device is not particularly limited. Inorganic oxides. The inorganic oxide is defined as various oxygen-containing gold metals whose metal element is mainly bonded to an oxygen atom to form a three-dimensional network. As the metal element constituting the inorganic oxide, for example, the element of the group 2 to the group 6 of the periodic table of the 10th halogen, more preferably, the oil is further selected from the group 3 to the 5th group of the periodic table of the halogen. The element. In particular, it is preferable that the element selected from the group consisting of a η and Δ is preferable, and the metal element is used as the colloidal dioxolysis effect and the uniformity of the uniform sentence is most suitable as the minute inorganic charge. Further, the shape of the fine inorganic filler may be any particle shape such as a spherical shape, a needle shape, a scaly shape, or a crushed shape, and is not particularly limited. The lower limit of the average particle diameter of the fine inorganic filler is preferably 1 Gnm more than 5 nm'. On the other hand, the upper limit of the average particle diameter of the fine inorganic filler is preferably 5 〇 nm, and particularly preferably 25. The reason is that if the average particle diameter of the two small inorganic fillers is less than the above range, it is minute. The surface energy of the sputum filling agent becomes high, and it is easy to cause agglutination, etc.; conversely, if the average particle control exceeds the above range, the white turbidity is caused by the short wavelength effect, and the transparency of the substrate layer 2 is lowered, which affects the wear. Transmittance. The base (4) 2 may contain an antistatic agent. As described above, the base material layer 2 is formed by a polymer resin of a mixture, and the liquid crystal display can be used to exhibit an antistatic effect, and can prevent adsorption of impurities, or, With the disadvantages of static electricity. If the antistatic agent is applied to the surface, the surface may be viscous or stained, but the antistatic agent may be reduced by the kneading of the antistatic agent in the substrate layer 2 as described above. The antistatic agent is not particularly limited, and examples thereof include an anionic antistatic agent such as a burnt-based sulfate or a pyryl phosphate; a cationic antistatic agent such as a fourth ammonium salt or an imidazoline compound; and a polyethylene glycol system. A nonionic antistatic agent such as polyoxyethylene sorbitan monostearate or ethanolamine, or a polymer antistatic agent such as polyacrylic acid. Among them, a cationic antistatic agent having a large antistatic effect is preferable, and an antistatic effect can be exhibited by adding a small amount. Further, the base material layer 2 may contain an ultraviolet absorber. By forming the base material layer 2 containing the ultraviolet absorber, the optical film 1 for the liquid crystal display device can be shielded from ultraviolet rays, and a small amount of ultraviolet light emitted from the light source of the backlight unit can be blocked to prevent the ultraviolet (four) liquid crystal layer. damage. Instead of the above ultraviolet absorber, an ultraviolet stabilizer (a molecular chain containing a base polymer having a UV stabilizer) may be used, or may be used together with an ultraviolet absorber. By the ultraviolet ray-eliminating agent, ultraviolet light can be generated by deactivation of the base, active oxygen, etc., to enhance ultraviolet stability and weather resistance. As the ultraviolet stabilizer, it is preferable to use the ultraviolet ray to have an ancient: qualitative hindered amine-based ultraviolet stabilizer, and by using a UV absorber together with an ultraviolet stabilizer to drag & drop & 'It can prevent the deterioration of ultraviolet rays and the weather resistance is exceptionally improved. 5: The lens array 3 is composed of a plurality of microlens microlens arrays 4 having substantially the same diameter, which are made by | ^ ^ ^ is composed of a number of microlenses 6 with a random direct control of 201030382. Further, a plurality of microlenses 6 in the microlens array 4 are formed in a random pattern and in a relatively dense manner. The microlens arrays 3 and 4 may be integrally formed with the base material layer 2 or may be formed separately from the base material layer 2. The microlens arrays 3 and 4 are formed of a transparent, particularly colorless, transparent synthetic resin because it is necessary to transmit light. Specifically, the same synthetic resin as the above-mentioned base material layer 2 can be used. Further, as the substrate layer 2, polyethylene terephthalate can be used: from the film, the polynaphthalene dicarboxylic acid
乙二酯膜或聚碳酸酯膜，於其上利用紫外線硬化性樹脂等 形成微透鏡5以及6。 此外，於基材層2、微透鏡5以及6,除了上述合成樹 脂以外，亦可配合例如填料、可塑劑、安定化劑劣化防 止劑、分散劑等。 、微透鏡5,係、具有凸狀之局部為大致球形之形狀，亦即 凸透鏡。作為微透鏡5的平均半徑為3/zm以上9〇以⑺以 下、特別是10”以上75_以下較佳。微透鏡5的平均 半徑若低於上述職，貝彳因受燈源所發出之光線的波長的 影響而有產生繞射現象之虞’相反地若超出上述範圍，則 於界面會不具有充分的光擴散性。 微透鏡5,係以相對緻密且以幾何學的方式配設於基材 層2表面。微透鏡5’於基材層2表面係以正三角形格子圖 案的方式㈣。因此’微透冑5的間㈣及透鏡間距離皆 為固定。該配設圖案，可使微透鏡5以最密 取在集的方式配設， 可^升該液晶顯示裝置用光學片1的聚光機能、光擴散機 能、變角機能等光學機能。 恢 201030382 作為微透鏡5之充塡率的下限，較佳為4〇%，特佳為 60%，最佳為70%。如上所述藉由使微透鏡5之充塡率設為 上述下限以上，可提升該液晶顯示裝置用光學片〗表面中 微透鏡5的占有面積，使該液晶顯示裝置用光學片丨之聚 光、光擴散等光學機能格外地提高。 作為微透鏡5之透鏡高度對曲率半徑之高度比 (H/R)的下限，較佳為5/8,特佳為3/4。另一方面，作 為該高度比（H/R)的上限，較料丄。此處所謂「透鏡高 度」，意指自微透鏡5基底面至最頂部為止之垂直距離。. 上所述藉由使微透鏡5之高度比（H/R)位於上述範圍， 可有效發揮微透鏡5中透鏡的折射作用，使該液晶顯示襄 置用光學片1之聚光、光擴散等光學機能格外地提高。 作為微透鏡5之透鏡間距離（s;p 一 D)對直徑（D)之間隔 比（S/D)的上限’較佳為1/2，特佳為。此處所謂「透 鏡間距離」，意指比鄰之一對微透鏡5間的最短距離。如 上所述藉由使微透鏡5之透鏡間距離（”設為上述上限以 下一可減 > 不賦予光學機能之平坦部，使該液晶顯示裝置 ❹ 用光學片1之聚光、光擴散等光學機能格外地提高。 _ '透鏡5之各個光線出射角度的平均，相對於液晶顯 示裝置用光學Μ ! lee、Α μ 4〇0 〇 片千面之法線，較佳為±25。以上，特佳為士 藉由以具有上述光線出射角度之微透鏡5來形成微透 歹】3’可獲得作為液晶顯示裝置用光學片所需之視 特性。 微透鏡6 ’係具有局部為大致球形之反轉形狀，亦即凹 12 201030382 透鏡。如上所述，因設置於基材層2背面之微透鏡陣列4 的微透鏡6為凹透鏡，故該液晶顯示裝置用光學片1的光 擴散性會格外地提高。亦即，藉由該液晶顯示裝置用光學 片1，來自背光的光線入射光學片1的背面時，因微透鏡6 凹狀之界面，使光線朝分散之方向（光擴散方向）折射，故可 提升光擴散性。 如上所述’藉由於該液晶顯示裝置用光學片1的兩面 形成微透鏡陣列3以及4，於光入射之背面，因凹狀之微透 ® 鏡6將光擴散而可獲得廣視野角；而於光出射之表面，因 凸狀之微透鏡5將光朝法線方向折射而可保持正面亮度。 特別疋，基材層2與微透鏡陣列3以及4以相同材料一體 化开^成時，該等折射係僅發生於液晶顯示裝置用光學片1 表面與背面之界面，亦即液晶顯示裝置用光學片丨内部不 會發生光的折射、散射等，故可使光於液晶顯示裝置用光 學片1内部的損失減到最小，提高光穿透率以及正面亮度。 作為微透鏡6的平均半徑，較佳為2以m以上60以爪以 下，特佳為6//m以上40以m以下。藉由使微透鏡6的平均 半徑位於上述範圍，於液晶顯示裝置用光學片丨背面之微 透鏡陣列4可有效使進入之來自背光的光線朝分散方向（光 擴散方向）折射’以提升光擴散性。微透鏡6的平均半徑若 低於上述範圍，則因受燈源所發出之光線的波長的影響而 有產生繞射現象之虞；若超出上述範圍，則不具有充分的 光擴散性。 微透鏡6的平均半徑，較佳為微透鏡$的平均半徑的1 13 201030382 /丨2以上丨以下。藉由使背面之微透鏡6與表面之微透鏡 5广平均半徑比設定於上述範圍’可一方面確保—定的正面 壳度，一方面提升光擴散性。微透鏡6的平均半徑若低於 微透鏡5的平均半#的1/12時，因散射以及繞射現象故 正面亮度會大幅減少，相反地若超過丨，則不具有充分的光 擴散性，亮度的均勻性會減少。 作為微透鏡6之充塡率的下限，較佳為5〇%，特佳為 70%，最佳為80%。藉由使上述微透鏡6之充塡率設為上述 下限以上，可提高於該光學片i表面中微透鏡6的占有面 積，使該液晶顯示裝置用光學片丨之光擴散等光學機能格 外地提高。 作為該液晶顯示裝置用光學片1之製造方法，只要可 形成上述構造者則無特別限定，可採用各種方法。做為該 液晶顯示裝置用光學片1之製造方法，可為：製作基材層2 之後’另外再形成微透鏡陣列3以及微透鏡陣列4之方法； 將基材層2、微透鏡陣列3以及微透鏡陣列4 一體成形之方 法’具體而言有如下之方法： (a) 於具有被透鏡陣列3以及4表面之反轉形狀之片模 具積層合成樹脂’然後去除該片模具，形成該液晶顯示裝 置用光學片1之方法； (b) 於具有微透鏡陣列3以及4表面之反轉形狀之金屬 模具，注入熔融樹脂之射出成型法； (c) 將板片化之樹脂再加熱’挾持於與前述相同之金屬 模具與金屬板之間，進行加壓轉印形狀之方法； 201030382 (d) 使炼融狀態之樹脂通過於周面具有微透鏡陣列3以 及4表面之反轉形狀的2個輥模具之間，以轉印上述形狀 之擠製片成形法，· (e) 於基材層上塗布紫外線硬化型樹脂，將其緊壓於具 有與上述相同之反轉形狀之片模具、金屬模具或輥模具， 使形狀轉印至未硬化之紫外線硬化型樹脂上，然後照射紫 外線’再使紫外線硬化型樹脂硬化之方法； (f) 將未硬化之紫外線硬化性樹脂充塡塗布於具有與上 ❿ 述相同之反轉形狀之金屬模具或輥模具上，再以基材層均 勻緊壓’然後照射紫外線使紫外線硬化型樹脂硬化之方法； (g) 使用電子線硬化型樹脂取代紫外線硬化型樹脂之方 法0 以下針對上述（d)〜（f)中使用輥模具之方法進行說明。 使用於表面具有微透鏡陣列3之反轉形狀之壓紋輥、以及 與該壓紋輥以既定的間隔平行配置，於表面具有微透鏡陣 列4之反轉形狀之壓紋輥，將膜狀樹脂通過上述2個壓紋 輥之間，藉此可一體形成表面之微透鏡陣列3與背面之微 透鏡陣列4。藉由該方法，可簡單且高精度地形成具有特定 之微透鏡陣列3以及4之光學片，並可簡單地利用同一材 質加以一體成形。進而，由於利用壓紋輥進行成形，故於 微透鏡陣列3以及4不會產生不連續之接轨部分，而可製 造無接縫之光學片。 作為通過2個壓紋輥之間之膜狀樹脂，可μ融樹脂， 亦可為片狀樹脂的兩面積層有未硬化樹脂者等，較佳為熔 15 201030382 融之熱可塑性樹脂自τ字模 拉！讲表成為膜狀者。如上所述， 藉由所謂擠製片成形法來 ^ ^ 造因可將於熔融狀態擠製之 樹月曰利用壓紋輥進行成形， 政了於膜成形時同時形成表面 M及背面之微透鏡陳列1 造該光學片。 及Ο因而可簡單且有效率地製 為上述具有微透鏡陣列3以及4之反轉形狀之模具 (f.屬模具、模型等）之製造方法，例如可利用以下方式製 =於基材上藉由光阻材料形成斑點狀之立體圖案，並對 :立體圖案加熱流體化使其曲面化，卩製作微透鏡陣列模 里’再於該微透鏡陣列模型的表面利用電鑛法積層金屬 層’然後將該金屬層剝離。 藉由上述製造方法，可簡單且確實地形成任意形狀之 微透鏡陣列3以及4。因此，構成微透鏡陣列3以及4之微 鏡乂及6的大小、充填率、配設圖案等可簡單且確實 地調整、結果使得該液晶顯示裝置用光學# ι之光學機能 可簡單且確實地受到控制。 作為上述具有微透鏡陣列3以及微透鏡陣列4之反轉 形狀之模具(片模具等)之其他製造方法，可利用以下方式製 造：使用於表面具有微透鏡陣列形狀之光學片原版，於光 學片原版的表©藉由冑製積層法來積層模具用合成樹脂 層然後將光學片原版自模具用合成樹脂層剝離。擠製積 層法中’可藉由特別是三明治擠製積層法，於光學片原版 與模具用基材片之間積層模具用合成樹脂層。 藉由上述製造方法，可利用擠製積層法將於表面具有 201030382 微透鏡陣列形狀之光學片原版的表面形狀忠實地轉印’故 可使具有高光擴散機能等光學性能的光學片生産性良好地 製把特別是，藉由三明治擠製積層法，可利用模具用基 材片確保光學片形成模具的強度，並可以光學片原版的表 面形狀的轉印性、对熱性、與光學層用合成樹脂層之剝離 性為重點來選擇構成模具用合成樹脂層之合成樹脂，而有 助於、屋精密计算之光學片材的表面形狀的精密追隨模具性 與光學片形成模具的高壽命化。 參 &外，藉由上述擠製積層法之製造方法，即使為具有 背面之微透鏡陣列4的反轉形狀的模具（微透鏡陣列4係由 具有隨機直徑之複數個微透鏡6所構成），亦可藉由塗佈具 有複數個直徑之珠粒所形成之光擴散片作為原版，再進行 轉印的方式簡單地製造。 圖2所示之邊光型背光單元，係具備導光板7、配設於 該導光板7的對偶邊之一對線狀燈源8、重疊配設於導光板 7表面側之液晶顯示裝置用光學片1。自燈源8所發射而從 導光板7表面出射之光線，雖具有相對法線方向傾斜既定 角度之比較強的峰值，但藉由該背光單元，在朝正面側的 聚光機能、朝法線方向側的變角機能方面，除了具有以往 的機能，且因具有格外優異之光擴散機能之該液晶顯示裝 置用光學片1，而可謀求亮度的均勻化，使其變換成具有寬 廣的視野角的光。因此，該背光單元，可謀求降低以往所 需光學片（珠粒塗覆片等）的裝設片數，增進薄型化 '高品質 化、以及低成本化〇進而，因降低光學片裝設片數，可增 17 201030382 進*度的提升。此外，邊光型背光單元，亦可裝備4管、6 管等燈源8。 圖3之液晶顯示裝置用光學片u，係具備基材層2、 於該基材層2表面所形成之微透鏡陣列3、以及該基材層2 背面所形成之微透鏡陣列12。該基材層以及微透鏡陣列3， 係與上述圖1之液晶顯示裝置用光學片1相同，故賦予相 同元件符號而省略其說明。 微透鏡陣列12，係由具有大致相同直徑之多數個微透 鏡1 3所構成。 微透鏡13，係凹透鏡。此外，微透鏡13之直徑，較佳 為與構成表面之微透鏡陣列3之微透鏡5相同直徑或低於 其直徑。 微透鏡13,係以相對緻密且以幾何學的方式配設於基 材層2背面。微透鏡13,於基材層2背面係以正三角形格 子圖案的方式配設。因此，微透鏡13的間距以及透鏡間距 離皆為固定。該配設圖案，可使微透鏡13以最密集的方式 配設’可提升該液晶顯示裝置用光學4 i的光擴散機能等❹ 光學機能。特別是，藉由以表面之微透鏡5的中心位於背 面之微透鏡13的中心的方式配設，或以構成表面之微⑽ Ρ車列3之正三角形格子圖案的各個三角形的中心位於背面 之微透鏡U的中心位置的方式配設，可提高表裏兩面的微 透鏡陣列的相乘效果’使光擴散機能等光學機能格外地提 係具備基材層2、 圖4之液晶顯示裝置用光學片21 18 201030382 於該基材層2表面所形成之微透鏡陣列3、以及於該基材層 2背面所形成之微透鏡陣列22。該基材層以及微透鏡陣列 3’係與上述圖1之液晶顯示裝置用光學片1相同，故賦予 相同元件符號而省略其說明。 微透鏡陣列22，係由具有隨機直徑之多數個微透鏡23 所構成。 微透鏡23，係凸透鏡。作為微透鏡23的平均半徑，係 與液晶顯示裝置用光學片1之微透鏡6相同，較佳為2//m 〇 以上“"爪以下’特佳為6"m以上18"m以下，其中又 以表面所設置之微透鏡5的平均半徑的1/12以上丨以下 較佳。此外，作為微透鏡23的充塡率的下限，較佳為, 特佳為70%、最佳為8〇〇/。。 此外，微透鏡23的平均焦點距離，可為基材層2的平 均厚度的1/ 2以下。藉由具有上述焦點距離之微透鏡23， 來自液晶顯示裝置用光學片21背面所入射之光線，經過背 面之微透鏡陣列22界面折射之後，於抵達表面所形成之微 ^ 透鏡陣列3前會被分散，故可提升該液晶顯示裝置用光學 片21的光擴散機能。 圖5之液晶顯示裝置用光學片31，係具備基材層2、 於該基材層2表面所形成之微透鏡陣列3、以及於該基材層 2背面所形成之微透鏡陣列32。該基材層以及微透鏡陣列 3，係與上述圖1之液晶顯示裝置用光學片〗相同，故賦予 相同元件符號而省略其說明。 微透鏡陣列3 2 ’係由具有大致相同直徑之多數個微透 19 201030382 鏡33所構成。 微透鏡33，係凸透鏡。微透鏡33之直徑，較佳為與構 成表面之微透鏡陣列3之微透鏡5相同直徑或低於其直 徑。藉由使微透鏡33之直徑設為與表面側之微透鏡5不同 大小，可進行因應對象物焦點距離之調整，而藉由組合表 面與背面之微透鏡可進一步提升光擴散性以及面均勻性。 微透鏡33，係以相對緻密且以幾何學的方式配設於基 材層2背面。微透鏡33，於基材層2背面係以正三角形格 子圖案的方式配設。因此，微透鏡33的間距以及透鏡間距 離皆為固定》該配設圖案，可使微透鏡33以最密集的方式 配設，可提升該液晶顯示裝置用光學片丨的光擴散機能等 光學機能。特別是，藉由以表面之微透鏡5的中心位於背 面之微透鏡33的中心的方式配設，或以構成表面之微透鏡 陣列3之正三角形格子圖案的各個三角形的中心位於背面 之微透鏡33的中心位置的方式配設，可提高表裏兩面的微 透鏡陣列的相乘效果，使光擴散機能等光學機能格外地提 高。 此外，微透鏡33的平均焦點距離，可為基材層2的平 均厚度的1/2以下。藉由具有上述焦點距離之微透鏡33， 來自液晶顯示裝置用光學片31背面所入射之光線，經過背 面之微透鏡陣列32界面折射之後，於抵達表面之微透鏡陣 列3前會被分散，故可提升該液晶顯示裝置用光學片31的 光擴散機能。 上述液晶顯示裝置用光學片n、2l以及31之任一者 201030382 中藉由液晶顯示裝置用光學片的兩面形成有微透鏡陣 列’入射之背面’因微透鏡13、23或33將光擴散而 可獲得儿度的均勻化以及廣視野角；而於光出射之表面， 因凸狀之微透鏡5將光朝法線方向折射而可保持高度正面 亮度。 卜本發明之液晶顯示裝置用光學片並無限定於上 述實施形態，例如，以表面之微透鏡之配設圖案而言，並 未限定於可祠密充填之上述正三角形格子圖案，亦可為正 ® ㈣格子圖案或隨機圖案。若為隨機圖案，於該液晶顯示 裝置用光學片與其他光學構件重合時可減少疊紋的產生。 此外，亦可於表面設置由凹透鏡之微透鏡所構成之微透鏡 陣列。於表面設置凹透鏡之微透鏡陣列時，亦具有與設置 上述凸透鏡之微透鏡陣列時同様優異之光擴散性等光學機 能。此外’表面之微透鏡與背面之微透鏡，亦可由分別不 同折射率之材料來形成。如上所述藉由使表面與背面由不 _ 同折射率材質所構成之微透鏡來形成，於材質間之界面亦 會產生光的折射等，故可提升該液晶表示用光學片的光擴 散性以及面均勻性。 實施例 以下根據實施例詳述本發明，但本發明並因本實施例 之記載而受限解釋。 〔比較例〕 於厚度lOOym之透明聚對苯二甲酸乙二醋製膜的表 面’使用設置有由凸透鏡之微透鏡所構成的微透鏡陣列之 21 201030382 液晶顯示裝置用光學片。將比較例之微透鏡片的微透鏡之 - 平均直徑設為60从m、充塡率設為70%的方式加以成形。 〔實施例1〜4〕 於厚度100 之透明聚對苯二曱酸乙二酯製膜的表 面’設置由凸透鏡之微透鏡所構成之微透鏡陣列，於背面 分別設置以下形狀之微透鏡陣列。藉由於背面設置由具有 隨機直徑之凹透鏡的微透鏡所構成之微透鏡陣列，得到實 施例1之液晶顯示裝置用光學片。藉由於背面設置由具有 大致相同直徑之凹透鏡的微透鏡所構成之微透鏡陣列，得 ❾ 到實施例2之液晶顯示裝置用光學片。藉由於背面設置由 具有隨機直徑之凸透鏡的微透鏡所構成之微透鏡陣列，得 到實施例3之液晶顯示裝置用光學片。藉由於背面設置由 具有大致相同直徑之凸透鏡的微透鏡所構成之微透鏡陣 列，得到實施例4之液晶顯示裝置用光學片。 於背面之微透鏡陣列中，將具有大致相同直徑之微透 鏡的平均直徑設為60 "m、將具有隨機直徑之微透鏡的平均 直徑設為12 μιη、將充塡率全部設為70%的方式加以成形。 ❹ 〔特性之評價〕 使用上述實施例1〜4之液晶顯示裝置用光學片以及比 較例之液晶顯示裝置用光學片，測定此等之霧度。霧度依 據JIS — Κ7136所規定之測定方法，藉由suga Test Instruments Co·，Ltd.之霧度試驗儀器加以測定。此外，使用 上述實施例2、4以及比較例之液晶顯示裝置用光學片，測 定該等之亮度半值角。進一步，使用上述實施例2、4以及 22 201030382 比較例之液晶顯示裝置用光學片，將該等之光學片實際裝 入直下型背光單元中，評價其光擴散性。光擴散性之評價， 係以目視確認從照射背光時的表面側之燈源影像的消去 度，藉由下述之基準進行評價。 (a) 幾乎看不見燈源影像的情況為@ (b) 不易看見燈源影像的情況為〇 (c) 稍微能夠看見燈源影像的情況為△ (句能夠清楚看見燈源影像的情況為χThe ethylene diester film or the polycarbonate film is formed thereon by the ultraviolet curable resin or the like to form the microlenses 5 and 6. Further, in addition to the above synthetic resin, the base material layer 2 and the microlenses 5 and 6 may be blended with, for example, a filler, a plasticizer, a stabilizer, a dispersant, or the like. The microlens 5, which has a convex shape, has a substantially spherical shape, that is, a convex lens. The average radius of the microlens 5 is 3/zm or more and 9〇 or less (7) or less, particularly preferably 10" or more and 75_ or less. If the average radius of the microlens 5 is lower than the above-mentioned position, the shellfish is emitted by the light source. The effect of the wavelength of the light may cause a diffraction phenomenon. Conversely, if it exceeds the above range, it will not have sufficient light diffusibility at the interface. The microlens 5 is relatively dense and geometrically arranged in The surface of the base material layer 2. The microlens 5' is in the form of a regular triangular lattice pattern on the surface of the base material layer 2 (4). Therefore, the distance between the micro-transparent 胄5 (4) and the distance between the lenses is fixed. The microlens 5 is disposed so as to be the most densely collected, and the optical function such as the condensing function, the light diffusing function, and the variable angle function of the optical sheet 1 for liquid crystal display device can be increased. The lower limit of the ratio is preferably 4% by weight, particularly preferably 60%, and most preferably 70%. As described above, by increasing the charge rate of the microlens 5 to the above lower limit, the optical device for the liquid crystal display device can be improved. The area occupied by the microlens 5 in the surface, so that the liquid crystal display device The optical function such as concentrating and diffusing the optical sheet is particularly improved. The lower limit of the height ratio (H/R) of the lens height to the radius of curvature of the microlens 5 is preferably 5/8, particularly preferably 3. On the other hand, as the upper limit of the height ratio (H/R), the term "lens height" means the vertical distance from the base surface to the topmost portion of the microlens 5. By setting the height ratio (H/R) of the microlens 5 to the above range, the refraction of the lens in the microlens 5 can be effectively exhibited, and the light collecting and light diffusing of the optical sheet 1 for liquid crystal display can be made. The optical function is exceptionally improved. The upper limit ′ of the ratio (S/D) of the inter-lens distance (s; p to D) to the diameter (D) of the microlens 5 is preferably 1/2, particularly preferably 1/2. Here, "distance between lenses" means the shortest distance between one of the adjacent microlenses 5. As described above, by setting the inter-lens distance of the microlens 5 ("the upper limit is equal to or less than the above upper limit", the flat portion of the optical function is not provided, and the liquid crystal display device is used for collecting light, diffusing light, etc. of the optical sheet 1. The optical function is particularly improved. _ 'The average of the light exit angles of the lens 5 is relative to the optical Μ lee, Α μ 4〇0 of the liquid crystal display device, preferably ±25. It is preferable for the microlens 5 having the above-mentioned light emission angle to form a microscopic lens 3' to obtain the optical characteristics required for the optical sheet for a liquid crystal display device. The microlens 6' has a partial substantially spherical shape. Inverted shape, that is, concave 12 201030382 lens. As described above, since the microlens 6 of the microlens array 4 provided on the back surface of the base material layer 2 is a concave lens, the light diffusing property of the optical sheet 1 for liquid crystal display device is exceptional. That is, when the light from the backlight is incident on the back surface of the optical sheet 1 by the optical sheet 1 for a liquid crystal display device, the light is refracted toward the direction of dispersion (light diffusion direction) due to the concave interface of the microlens 6 , Therefore, the light diffusing property can be improved. As described above, the microlens arrays 3 and 4 are formed on both sides of the optical sheet 1 for liquid crystal display device, and the light is diffused by the concave micro-transparent mirror 6 on the back surface of the light incident. A wide viewing angle can be obtained. On the surface of the light exit, the front surface brightness can be maintained by the convex microlens 5 refracting the light toward the normal direction. In particular, the substrate layer 2 and the microlens arrays 3 and 4 are made of the same material. When the integrated film is formed, the refraction only occurs at the interface between the front surface and the back surface of the optical sheet 1 for a liquid crystal display device, that is, the light is not refracted or scattered inside the optical sheet for a liquid crystal display device. The loss of light inside the optical sheet 1 for liquid crystal display device is minimized, and the light transmittance and the front luminance are improved. The average radius of the microlens 6 is preferably 2 or more and 60 or less, and more preferably 6/min. /m or more is 40 or less. By making the average radius of the microlens 6 within the above range, the microlens array 4 on the back surface of the optical sheet for liquid crystal display device can effectively bring the light from the backlight into the dispersion direction (light diffusion) direction) Refraction 'to enhance light diffusivity. If the average radius of the microlens 6 is lower than the above range, there is a diffraction phenomenon due to the influence of the wavelength of the light emitted by the light source; if it exceeds the above range, it does not have Sufficient light diffusivity. The average radius of the microlens 6 is preferably 1 13 201030382 / 丨 2 or more 平均 below the average radius of the microlens $. By making the microlens 6 on the back surface and the microlens 5 on the surface have a wide average radius The ratio is set to the above range to ensure a positive frontal shell on the one hand and to enhance light diffusivity on the one hand. The average radius of the microlens 6 is less than 1/12 of the average half of the microlens 5 due to scattering and winding. Since the front side brightness is greatly reduced, if it exceeds 丨, it does not have sufficient light diffusibility, and the uniformity of brightness is reduced. The lower limit of the charge rate of the microlens 6 is preferably 5% by weight, particularly preferably 70%, and most preferably 80%. By setting the charge rate of the microlens 6 to the lower limit or higher, the area occupied by the microlens 6 on the surface of the optical sheet i can be increased, and the optical function such as light diffusion of the optical sheet for the liquid crystal display device can be exceptionally improve. The method for producing the optical sheet 1 for a liquid crystal display device is not particularly limited as long as the above-described structure can be formed, and various methods can be employed. As a method of manufacturing the optical sheet 1 for a liquid crystal display device, a method of separately forming the microlens array 3 and the microlens array 4 after the base layer 2 is formed; the base layer 2, the microlens array 3, and The method of integrally forming the microlens array 4 is specifically as follows: (a) laminating a synthetic resin with a sheet mold having an inverted shape of the surfaces of the lens arrays 3 and 4, and then removing the sheet mold to form the liquid crystal display (b) a metal mold having an inverted shape of the surface of the microlens arrays 3 and 4, and an injection molding method of injecting a molten resin; (c) reheating the slab-formed resin a method of performing a pressure transfer transfer between the metal mold and the metal plate as described above; 201030382 (d) Passing the resin in the fused state through two of the inverted shapes of the surface of the microlens array 3 and 4 on the circumferential surface An extrusion sheet forming method in which the above shape is transferred between the roll dies, (e) applying an ultraviolet curable resin to the base material layer, and pressing it against a sheet mold and metal having the same reverse shape as described above a mold or a roll mold, a method of transferring a shape onto an uncured ultraviolet curable resin, and then irradiating ultraviolet rays to cure the ultraviolet curable resin; (f) applying an uncured ultraviolet curable resin to the resin The method of hardening the ultraviolet curable resin by uniformly pressing the base material layer and then irradiating the ultraviolet ray on the metal mold or the roll mold of the same reverse shape; (g) replacing the ultraviolet curing type with an electron ray curing resin Method of Resin 0 Hereinafter, a method of using a roll mold in the above (d) to (f) will be described. An embossing roll having an inverted shape of the microlens array 3 on the surface, and an embossing roll having a reversed shape of the microlens array 4 on the surface in parallel with the embossing roll at a predetermined interval, the film-like resin By passing between the above two embossing rolls, the microlens array 3 on the surface and the microlens array 4 on the back side can be integrally formed. By this method, the optical sheets having the specific microlens arrays 3 and 4 can be formed simply and accurately, and can be integrally formed by simply using the same material. Further, since the embossing rolls are used for forming, the microlens arrays 3 and 4 do not generate discontinuous portions, and a seamless optical sheet can be produced. As the film-like resin passing between the two embossing rolls, the resin may be melted, or the two-layer layer of the sheet-like resin may be uncured resin or the like, and it is preferably melted 15 201030382. The thermoplastic resin is melted from the τ-shaped mold. ! The storytelling becomes a membranous person. As described above, by the so-called extrusion sheet forming method, the squeezing roller which is extruded in a molten state can be formed by an embossing roll, and the microlens of the surface M and the back surface are simultaneously formed at the time of film formation. Exhibition 1 made the optical sheet. Therefore, the manufacturing method of the above-described mold having the inverted shape of the microlens arrays 3 and 4 (f. belonging to a mold, a mold, etc.) can be easily and efficiently produced, for example, by using the following method: Forming a speckled three-dimensional pattern from the photoresist material, and heating and fluidizing the three-dimensional pattern to make it curved, and then fabricating the microlens array mold and then using the electromineral method to laminate the metal layer on the surface of the microlens array model. The metal layer was peeled off. According to the above manufacturing method, the microlens arrays 3 and 4 of any shape can be formed simply and surely. Therefore, the size, filling ratio, arrangement pattern, and the like of the micromirrors 乂 and 6 constituting the microlens arrays 3 and 4 can be easily and surely adjusted, and as a result, the optical function of the optical display device can be simply and surely Be controlled. Another manufacturing method of the above-described mold (sheet mold or the like) having the inverted shape of the microlens array 3 and the microlens array 4 can be manufactured by using an optical sheet original having a microlens array shape on the surface, and an optical sheet. In the original sheet, a synthetic resin layer for a mold is laminated by a tantalum lamination method, and then the optical sheet original is peeled off from the synthetic resin layer for a mold. In the extrusion lamination method, a synthetic resin layer for a mold can be laminated between the optical sheet original and the substrate sheet for a mold by a sandwich extrusion method. According to the above manufacturing method, the surface shape of the optical sheet precursor having the shape of the 201030382 microlens array on the surface can be faithfully transferred by the extrusion lamination method, so that the optical sheet having optical properties such as high light diffusion function can be produced with good productivity. In particular, by the sandwich extrusion lamination method, the strength of the optical sheet forming mold can be ensured by the substrate sheet for the mold, and the transfer property of the surface shape of the optical sheet original, the heat, and the synthetic resin for the optical layer can be used. In order to select the synthetic resin constituting the synthetic resin layer for the mold, the precision of the surface shape of the optical sheet which is calculated by the house is closely followed by the moldability and the life of the optical sheet forming mold. In addition, by the manufacturing method of the above-described extrusion lamination method, even a mold having an inverted shape of the microlens array 4 on the back surface (the microlens array 4 is composed of a plurality of microlenses 6 having a random diameter) Alternatively, the light-diffusing sheet formed by coating beads having a plurality of diameters may be simply used as a master and then transferred. The edge light type backlight unit shown in FIG. 2 is provided with a light guide plate 7, a pair of paired side light sources 8 disposed on the light guide plate 7, and a liquid crystal display device which is disposed on the surface side of the light guide plate 7 in a superposed manner. Optical sheet 1. The light emitted from the light source 8 and emitted from the surface of the light guide plate 7 has a relatively strong peak inclined at a predetermined angle with respect to the normal direction. However, the backlight unit has a concentrating function toward the front side and toward the normal line. In addition to the conventional function, the optical sheet 1 for a liquid crystal display device having an excellent light diffusing function can be used to achieve a uniform viewing angle and a wide viewing angle. Light. Therefore, in the backlight unit, it is possible to reduce the number of optical sheets (bead coated sheets, etc.) required in the related art, and to improve the thickness and the quality of the optical sheet, and to reduce the cost. The number can be increased by 17 201030382. In addition, the edge light type backlight unit can also be equipped with a light source 8 such as 4 tubes or 6 tubes. The optical sheet u for a liquid crystal display device of Fig. 3 includes a base material layer 2, a microlens array 3 formed on the surface of the base material layer 2, and a microlens array 12 formed on the back surface of the base material layer 2. The base material layer and the microlens array 3 are the same as those of the optical sheet 1 for a liquid crystal display device of Fig. 1, and the same reference numerals are given to the same reference numerals, and the description thereof will be omitted. The microlens array 12 is composed of a plurality of microlenses 13 having substantially the same diameter. The microlens 13 is a concave lens. Further, the diameter of the microlens 13 is preferably the same as or smaller than the diameter of the microlens 5 of the microlens array 3 constituting the surface. The microlens 13 is disposed on the back surface of the substrate layer 2 in a relatively dense and geometric manner. The microlens 13 is disposed on the back surface of the base material layer 2 in an equilateral triangle pattern. Therefore, the pitch of the microlenses 13 and the lens pitch are both fixed. By arranging the pattern, the microlens 13 can be disposed in the most dense manner, and the optical function of the light diffusing function of the liquid crystal display device can be improved. In particular, it is disposed such that the center of the microlens 5 on the surface is located at the center of the microlens 13 on the back side, or the center of each triangle of the regular triangular lattice pattern constituting the surface of the micro (10) brake train 3 is located on the back side. The center position of the microlens U is arranged so as to improve the multiplication effect of the microlens array on both sides of the surface. The optical function such as the light diffusing function can be additionally provided with the substrate layer 2, and the optical sheet for the liquid crystal display device of FIG. 21 18 201030382 A microlens array 3 formed on the surface of the substrate layer 2, and a microlens array 22 formed on the back surface of the substrate layer 2. The base material layer and the microlens array 3' are the same as those of the optical sheet 1 for a liquid crystal display device of Fig. 1, and the same reference numerals will be given thereto, and the description thereof will be omitted. The microlens array 22 is composed of a plurality of microlenses 23 having a random diameter. The microlens 23 is a convex lens. The average radius of the microlens 23 is the same as that of the microlens 6 of the optical sheet 1 for a liquid crystal display device, and is preferably 2//m 〇 or more and "" below the claw" is preferably 6 "m or more and 18" Further, it is preferable that the average radius of the microlens 5 provided on the surface is 1/12 or more and 丨 or less. Further, as the lower limit of the filling factor of the microlens 23, it is preferably 70% or more preferably 8 Further, the average focal length of the microlens 23 may be 1/2 or less of the average thickness of the base material layer 2. The microlens 23 having the above-described focal length is derived from the back surface of the optical sheet 21 for a liquid crystal display device. The incident light is refracted through the interface of the microlens array 22 on the back surface, and is dispersed in front of the microlens array 3 formed on the surface, so that the light diffusing function of the optical sheet 21 for the liquid crystal display device can be improved. The optical sheet 31 for a liquid crystal display device includes a base material layer 2, a microlens array 3 formed on the surface of the base material layer 2, and a microlens array 32 formed on the back surface of the base material layer 2. The layer and the microlens array 3 are connected to the above FIG. The optical lens of the crystal display device is the same, and the same reference numerals will be given, and the description thereof will be omitted. The microlens array 3 2 ' is composed of a plurality of micro-transparent 19 201030382 mirrors 33 having substantially the same diameter. The microlens 33 is a convex lens. The diameter of the microlens 33 is preferably the same as or smaller than the diameter of the microlens 5 constituting the surface of the microlens array 3. By making the diameter of the microlens 33 different from the size of the microlens 5 on the surface side, According to the adjustment of the focal length of the object, the light diffusibility and the surface uniformity can be further improved by combining the microlenses on the surface and the back surface. The microlens 33 is relatively densely and geometrically disposed on the substrate layer. 2, the back surface. The microlens 33 is disposed on the back surface of the base material layer 2 in a regular triangular lattice pattern. Therefore, the pitch of the microlenses 33 and the distance between the lenses are all fixed, and the microlens 33 can be used. In the most dense manner, the optical function such as the light diffusing function of the optical sheet for the liquid crystal display device can be improved. In particular, the center of the microlens 5 on the surface is located at the back side. The center of the microlens 33 is disposed in such a manner that the center of each triangle of the equilateral triangle lattice pattern constituting the surface of the microlens array 3 is disposed at the center of the microlens 33 on the back surface, and the microlenses on both sides of the surface can be improved. The multiplication effect of the array is such that the optical function of the light diffusing function can be particularly improved. Further, the average focal length of the microlens 33 can be 1/2 or less of the average thickness of the base material layer 2. By having the above-mentioned focal length The lens 33, the light incident from the back surface of the optical sheet 31 for liquid crystal display device is refracted through the interface of the microlens array 32 on the back surface, and is dispersed before the microlens array 3 reaching the surface, so that the optical device for the liquid crystal display device can be improved. The light diffusing function of the sheet 31. In any of the optical sheets n, 21, and 31 for liquid crystal display devices of the above-described liquid crystal display device 201030382, a microlens array 'incident back surface' is formed by both surfaces of the optical sheet for liquid crystal display device, and the light is diffused by the microlenses 13, 23 or 33. The uniformity of the child's degree and the wide viewing angle can be obtained. On the surface of the light exiting, the convex microlens 5 refracts the light toward the normal direction to maintain a high frontal brightness. The optical sheet for a liquid crystal display device of the present invention is not limited to the above embodiment. For example, the pattern of the microlens on the surface is not limited to the above-mentioned equilateral triangular lattice pattern which can be densely filled, or Positive® (four) plaid pattern or random pattern. If it is a random pattern, the generation of the moiré can be reduced when the optical sheet for the liquid crystal display device is overlapped with other optical members. Further, a microlens array composed of microlenses of concave lenses may be provided on the surface. When the microlens array of the concave lens is provided on the surface, it also has an optical function such as excellent light diffusibility when the microlens array of the above-mentioned convex lens is provided. Further, the 'microlens of the surface and the microlens of the back surface may be formed of materials having different refractive indices, respectively. As described above, the surface and the back surface are formed by microlenses which are not composed of the same refractive index material, and light is refracted at the interface between the materials, so that the light diffusibility of the optical sheet for liquid crystal display can be improved. And uniformity of the face. EXAMPLES Hereinafter, the present invention will be described in detail based on examples, but the present invention is limited by the description of the examples. [Comparative Example] An optical sheet for a liquid crystal display device was used in the surface of a transparent polyethylene terephthalate film having a thickness of 100 μm, using a microlens array provided with a microlens of a convex lens. The microlens of the microlens sheet of the comparative example was molded so that the average diameter was 60 and the filling rate was 70%. [Examples 1 to 4] A microlens array composed of a microlens of a convex lens was provided on the surface of a transparent polyethylene terephthalate film having a thickness of 100, and a microlens array of the following shape was provided on the back surface. An optical sheet for a liquid crystal display device of Example 1 was obtained by providing a microlens array composed of a microlens having a concave lens having a random diameter on the back surface. The optical sheet for a liquid crystal display device of Example 2 was obtained by providing a microlens array composed of microlenses having concave lenses having substantially the same diameter on the back surface. An optical sheet for a liquid crystal display device of Example 3 was obtained by providing a microlens array composed of microlenses having a convex lens having a random diameter on the back surface. An optical sheet for a liquid crystal display device of Example 4 was obtained by providing a microlens array composed of microlenses having convex lenses having substantially the same diameter on the back surface. In the microlens array on the back side, the average diameter of the microlenses having substantially the same diameter is set to 60 "m, the average diameter of the microlenses having a random diameter is set to 12 μm, and the filling rate is all set to 70%. The way to shape it.评价 [Evaluation of Characteristics] The haze of the optical sheet for liquid crystal display devices of the above Examples 1 to 4 and the optical sheet for a liquid crystal display device of Comparative Example were measured. The haze was measured by a haze tester of Suga Test Instruments Co., Ltd. in accordance with the measurement method specified in JIS - Κ 7136. Further, using the optical sheets for liquid crystal display devices of Examples 2 and 4 and Comparative Examples described above, the half value angles of the luminances were measured. Further, the optical sheets for liquid crystal display devices of Comparative Examples 2, 4 and 22 201030382 were used, and the optical sheets were actually mounted in a direct type backlight unit, and the light diffusibility thereof was evaluated. The evaluation of the light diffusibility was carried out by visually confirming the degree of erasure of the light source image on the surface side when the backlight was irradiated, and evaluated by the following criteria. (a) The case where the light source image is almost invisible is @ (b) The case where the light source image is difficult to see is 〇 (c) The case where the light source image is slightly visible is △ (The sentence can clearly see the light source image as χ
其結果示於表1。此外，分別將比較例之液晶顯示裝置 用光學片裝入直下型背光單元時的燈源影像照片示於圖 6、將實施例2之液晶顯示裴置用光學片裝入直下型背光單 π時的燈源影像照片示於圖7、將實施例4之液晶顯示裝置 用光學片裝入直下型背光單元時的燈源影像照片示於圖8。The results are shown in Table 1. Further, the light source image of the liquid crystal display device for a liquid crystal display device of the comparative example is shown in FIG. 6, and the optical film for liquid crystal display device of the second embodiment is incorporated in a direct type backlight π. The light source image of the light source image shown in Fig. 7 is shown in Fig. 8 when the optical sheet for the liquid crystal display device of the fourth embodiment is incorporated in the direct type backlight unit.
表1Table 1
如上述表1所示，實施例1〜4的液晶顯示裝置用光學 片，相較於背面不具備微透鏡陣列之比較例的液晶顯示裝 置用光學片’顯示了較高的霧度，亦即表示具有較高的光 擴散性以及寬廣的視野角。此外，若於實施例丨〜4之間比 23 201030382 較，則背面之微透鏡具有隨機直徑，且具有凹透鏡形狀者 顯示了較高的霧度’亦即顯示具有較高的光擴散性以及寬 廣的視野角。As shown in the above Table 1, the optical sheets for liquid crystal display devices of Examples 1 to 4 exhibited higher haze than the optical sheets for liquid crystal display devices of Comparative Examples having no microlens array on the back surface, that is, Indicates high light diffusivity and a wide viewing angle. In addition, if the ratio between the embodiments 丨4 and 4 is higher than 23 201030382, the microlens on the back side has a random diameter, and the shape of the concave lens shows a higher haze, that is, the display has higher light diffusibility and broadness. The angle of view.
此外，如表1所示，實施你丨2 w n I X孢例2以及4之液晶顯示裝置 用光學片，相較於背面不具備微透鏡陣列之比較例的液晶 顯示裝置用光學片，具有較寬的亮度半值角。 進而’如表1以及圖7〜9所示’實施例2以及4的液 晶顯示裝置用光學片，其燈源影像之消去度亦較高。亦即， 顯示實施例2以及4之液晶顯示裝置用光學片，具有較高 之光擴散性以及寬廣的視野角。此外，從燈源影像之消^ 度（圖8與圖9之比較）中，顯示背面具有凹透鏡形狀之微透 鏡的液晶顯示裝置用光學片’具有較高之光擴散 視野角。 產業上之可利用性 如上所述，本發明之液晶顯示裝置用光學片，可作為 ❹ 液晶顯示裝置之背光單元的構成要素，特別是適合用於穿 透型液晶顯示裝置。 【圖式簡單說明】 圖1係表示本發明之一特定實施形態之液晶顯示裝 用光學片之示意性的局部截面圖。 。-圖_2係表不具備圖i之液晶顯示裝置用光學片之背光 單το之示意性的載面圖。 圖3係表示與圊1之液晶顯示裝置用光學片不同形態 24 201030382 之液晶顯示装置用光學片之示意性的局部截面圖。 圖4係表不與圖1以及圖3之液晶顯示裝置用光學片 不同之液晶顯示裝置用光學片之示意性的局部截面圖。 圖5係表示與圖1、圖3以及圖4之液晶顯示裝置用光 學片不同之液晶顯示裝置用光學片之示意性的局部戴面 圖0 圖6係表示比較例之液晶顯示裝置用光學片裝入直下 型背光單元時的燈源影像照片。 圖7係表示實施例2之液晶顯示裝置用光學片裝入直 下型背光單元時的燈源影像照片。 圖8係表示實施例4之液晶顯示裝置用光學片裝入直 下型背光單元時的燈源影像照片。 圖9(a)以及（b)係表示一般背光單元之示意性的透視 圖’以及表示以往之一般微透鏡片之示意性的截面圖。 【主要元件符號說明】 1 液晶顯示裝置用光學片 2 基材層 3 微透鏡陣列 4 微透鏡陣列 5 微透鏡 6 微透鏡 7 導光板 8 燈源 25 201030382 11 液晶顯示裝置用光學片 12 微透鏡陣列 13 微透鏡 21 液晶顯示裝置用光學片 22 微透鏡陣列 23 微透鏡 31 液晶顯示裝置用光學片 32 微透鏡陣列 33 微透鏡 40 背光單元 41 燈源 42 導光板 43 光學片 44 微透鏡片 45 棱鏡片 46 棱鏡部 微透鏡陣列 47Further, as shown in Table 1, the optical sheets for liquid crystal display devices of the examples 2 and 4 of the 丨2 wn IX are more widely used than the optical sheets for liquid crystal display devices of the comparative examples having no microlens array on the back side. The half value angle of the brightness. Further, as shown in Table 1 and Figs. 7 to 9, the optical sheets for liquid crystal display devices of Examples 2 and 4 have high erasure of the light source image. That is, the optical sheets for liquid crystal display devices of Examples 2 and 4 were shown to have high light diffusibility and a wide viewing angle. Further, from the erasing degree of the light source image (comparison of Fig. 8 and Fig. 9), the optical sheet for liquid crystal display device which has a microlens having a concave lens shape on the back surface has a high light diffusion viewing angle. Industrial Applicability As described above, the optical sheet for a liquid crystal display device of the present invention can be used as a constituent element of a backlight unit of a liquid crystal display device, and is particularly suitable for use in a transmissive liquid crystal display device. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic partial cross-sectional view showing an optical sheet for liquid crystal display according to a specific embodiment of the present invention. . - Figure 2 is a schematic plan view showing the backlight of the optical sheet for liquid crystal display device of Figure i. Fig. 3 is a schematic partial cross-sectional view showing an optical sheet for a liquid crystal display device in a different form from the optical sheet for a liquid crystal display device of 圊1, 24 201030382. Fig. 4 is a schematic partial cross-sectional view showing an optical sheet for a liquid crystal display device which is different from the optical sheet for a liquid crystal display device of Figs. 1 and 3. 5 is a schematic partial surface view showing an optical sheet for a liquid crystal display device different from the optical sheets for liquid crystal display devices of FIGS. 1, 3, and 4, and FIG. 6 is a view showing an optical sheet for a liquid crystal display device of a comparative example. Light source image when loading a direct type backlight unit. Fig. 7 is a view showing a light source image when the optical sheet for a liquid crystal display device of the second embodiment is incorporated in a direct type backlight unit. Fig. 8 is a view showing a light source image when the optical sheet for a liquid crystal display device of the fourth embodiment is incorporated in a direct type backlight unit. Figs. 9(a) and 9(b) are schematic perspective views showing a general backlight unit and a schematic cross-sectional view showing a conventional general lenticular sheet. [Explanation of main component symbols] 1 Optical sheet for liquid crystal display device 2 Substrate layer 3 Microlens array 4 Microlens array 5 Microlens 6 Microlens 7 Light guide plate 8 Light source 25 201030382 11 Optical sheet for liquid crystal display device 12 Microlens array 13 Microlens 21 Optical sheet for liquid crystal display device 22 Microlens array 23 Microlens 31 Optical sheet for liquid crystal display device 32 Microlens array 33 Microlens 40 Backlight unit 41 Light source 42 Light guide plate 43 Optical sheet 44 Microlens sheet 45 Prism sheet 46 prism portion microlens array 47