JP2657536B2 - Light diffusion sheet - Google Patents
Light diffusion sheetInfo
- Publication number
- JP2657536B2 JP2657536B2 JP27395288A JP27395288A JP2657536B2 JP 2657536 B2 JP2657536 B2 JP 2657536B2 JP 27395288 A JP27395288 A JP 27395288A JP 27395288 A JP27395288 A JP 27395288A JP 2657536 B2 JP2657536 B2 JP 2657536B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- refractive index
- diffusion sheet
- light diffusion
- diffusing agent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Optical Elements Other Than Lenses (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は透明性に優れ、かつ光の反射損失が少なく、
光の拡散効率の高い光拡散シートに関し、特に透過型投
影スクリーンに使用した場合に有用な光拡散シートに関
する。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is excellent in transparency, has low light reflection loss,
The present invention relates to a light diffusion sheet having high light diffusion efficiency, and more particularly to a light diffusion sheet useful when used in a transmission type projection screen.
（従来の技術） 透過型投影スクリーンや照明に用いられる光拡散シー
トとしては、透明または半透明の基材中にシリカ、ガラ
ス、アルミナ等の微細な粒子からなる拡散剤を分散した
ものが知られている。このような光拡散シートは、基材
として熱可塑性樹脂を使用したものが、基材樹脂と拡散
剤を混合し同時に押し出し成形してシートすることが可
能であり、その後の加工により所望の形状の成形するこ
とも容易なので、広く一般に用いられている。(Prior Art) As a light diffusion sheet used for a transmission type projection screen or illumination, a light diffusion sheet in which a diffusing agent composed of fine particles of silica, glass, alumina or the like is dispersed in a transparent or translucent base material is known. ing. Such a light diffusion sheet can be formed by using a thermoplastic resin as a base material, mixing the base resin and a diffusing agent, extruding the mixture at the same time, and forming a sheet having a desired shape by subsequent processing. Since it is easy to mold, it is widely and generally used.
（発明が解決しようとする課題） しかしながら、上記の光拡散シートを透過型投影スク
リーンに使用した場合には、視野角度（拡散角）の拡大
のために、基材中に分散する拡散剤の量を増加、又は拡
散剤と基材の屈折率差を大きくしていくと、画像の透明
感が失われ濁りを生じたり、光源光の光量損失が大きく
コントラストが低下してしまう等の問題があった。この
ため、拡散剤の分散量も画像品質の劣化を起こさない範
囲にとどめる必要があり、所望の拡散特性を得られない
ことがあった。(Problems to be Solved by the Invention) However, when the above-mentioned light diffusion sheet is used for a transmission type projection screen, the amount of the diffusing agent dispersed in the base material is increased in order to enlarge the viewing angle (diffusion angle). When the refractive index difference between the diffusing agent and the base material is increased, the transparency of the image is lost and the image becomes turbid, and the light amount of the light from the light source is greatly reduced and the contrast is reduced. Was. For this reason, the amount of dispersion of the diffusing agent must be kept within a range that does not cause deterioration of image quality, and a desired diffusion characteristic may not be obtained.
このような問題点は、基材の拡散剤の界面において屈
折率の差による光の反射が生じることに起因することが
わかってきた。拡散剤による光の拡散の原理は、基材と
拡散剤の界面において基材と拡散剤の屈折率が異なる場
合に、スネルの法則で表される光の屈折が生じることに
よるが、このときに屈折と同時に光の反射が起こること
が知られている。光源から投影され基材と拡散剤の間で
屈折を繰り返して観察者側へ進む光は観察者に認識され
る有効な光となる。これに対して、基材と拡散剤の界面
で反射され、光拡散シートの面内方向や光源側に進む光
は損失光となる。このような反射損失が大きいと、コン
トラストが低下し、拡散効率も悪くなってしまい、さら
に反射により散乱された光が他の光源光と混ざり合うの
で、画像の濁りや解像度の低下が生じてしまうと考えら
れる。It has been found that such a problem is caused by light reflection due to a difference in refractive index at the interface of the diffusing agent of the substrate. The principle of light diffusion by a diffusing agent is based on the fact that when the refractive index of the substrate and the diffusing agent is different at the interface between the substrate and the diffusing agent, light refraction expressed by Snell's law occurs. It is known that light reflection occurs simultaneously with refraction. The light projected from the light source and traveling toward the observer by repeating refraction between the base material and the diffusing agent becomes effective light recognized by the observer. On the other hand, light that is reflected at the interface between the base material and the diffusing agent and that travels in the in-plane direction of the light diffusion sheet or toward the light source is lost light. When such a reflection loss is large, the contrast is reduced, the diffusion efficiency is deteriorated, and the light scattered by the reflection is mixed with other light sources, so that the image becomes turbid and the resolution is reduced. it is conceivable that.
本発明は上記の事情に鑑み、透過型スクリーンに使用
した場合にも、画像の透明性に優れ、光源光の光量損失
が少なく、かつ良好な拡散特性を得られる光拡散シート
の提供を目的とする。The present invention has been made in view of the above circumstances, and has an object to provide a light diffusion sheet which is excellent in image transparency, has a small light amount loss of light from a light source, and can obtain good diffusion characteristics even when used in a transmission screen. I do.
（課題を解決するための手段） 上記の目的を達成するため、本発明の光拡散シートは
最外縁部３の屈折率がn0、中心部４の屈折率がn0＜niな
る屈折率niであって、最外縁部から中心部に向かって屈
折率がn0からniまで連続的あるいは段階的に増加してな
る光拡散剤２を、屈折率n0にほぼ等しい透明基材１中に
分散した構成とした。すなわち、 （ａ） 透明基材１と拡散剤２との界面における屈折率
差を小さくすることにより、界面の反射を減少させ、 （ｂ） 拡散性を大きくするために拡散剤２の最外縁部
３から中心部４に向かってできるだけ透明基材１との屈
折率差が大きくなるようにし、 （ｃ） かつ拡散剤２の最外縁部３から中心部４にむか
う方向および中心部から最外縁部に向かう方向のあらゆ
る部分において屈折率差が大きくならないように、微小
な屈折率の差を有した層５に分割するか、あるいは連続
的に屈折率が変化するようにした。(Means for Solving the Problems) In order to achieve the above object, in the light diffusion sheet of the present invention, the refractive index of the outermost edge portion 3 is n 0 , and the refractive index of the central portion 4 is n 0 <n i. a n i, approximately equal transparent substrate a light diffusing agent 2, the refractive index n 0 the refractive index towards the center from the outermost edge becomes continuously or stepwise increased from n 0 to n i 1 were dispersed. That is, (a) reducing the difference in the refractive index at the interface between the transparent substrate 1 and the diffusing agent 2 to reduce the reflection at the interface, and (b) the outermost edge of the diffusing agent 2 to increase the diffusivity. (C) and a direction from the outermost edge 3 of the diffusing agent 2 to the center 4 and from the center to the outermost edge of the diffusing agent 2. In order to prevent the refractive index difference from becoming large in any part in the direction toward, the layer is divided into layers 5 having a small refractive index difference, or the refractive index is changed continuously.
第１図は本発明の光拡散シートの部分拡大図である。
第１図（ａ）に屈折率を多層分割して変化させた拡散剤
を使用した場合を、第１図（ｂ）に屈折率を連続変化さ
せた場合の拡散剤を使用した場合を示す。FIG. 1 is a partially enlarged view of the light diffusion sheet of the present invention.
FIG. 1 (a) shows a case where a diffusing agent whose refractive index is changed by dividing into multiple layers is used, and FIG. 1 (b) shows a case where a diffusing agent whose refractive index is continuously changed is used.
第２図は本発明の原理を説明するための図であり、第
２図（ａ）は従来の光拡散シート、第２図（ｂ）は本発
明の光拡散シートを示す。説明を簡単にするために、透
明基材から拡散剤の一部分の平面に近似される面に垂直
に光が入射される場合について述べると、このときの光
のエネルギー反射率は Ｒ＝（n0−ni）2/（n0＋ni）２ n0:透明基材の屈折率 ni:拡散剤の屈折率 で表される。FIG. 2 is a view for explaining the principle of the present invention. FIG. 2 (a) shows a conventional light diffusing sheet, and FIG. 2 (b) shows a light diffusing sheet of the present invention. For the sake of simplicity, the case where light is incident perpendicularly to a plane approximating the plane of a part of the diffusing agent from the transparent substrate will be described. At this time, the energy reflectance of light is R = (n 0 −n i ) 2 / (n 0 + n i ) 2 n 0 : Refractive index of transparent substrate ni : Refractive index of diffusing agent
第２図（ａ）において、透明基材７にポリメチルメタ
クリレート（n0＝1.49）、拡散剤８にni＝1.54のガラス
を使用した場合の表面反射は0.0273％となる。拡散剤か
ら透明基材に出光する際にも同様の反射があるので、表
面反射の総計は 0.0540％ となる。In FIG. 2 (a), polymethylmethacrylate transparent substrate 7 (n 0 = 1.49), the surface reflection in the case of using the glass of the n i = 1.54 to diffusing agent 8 will be 0.0273%. Since the same reflection occurs when light is emitted from the diffusing agent to the transparent substrate, the total surface reflection is 0.0540%.
これに対して第２図（ｂ）において、透明基材にポリ
メチルメタクリレートを用い、拡散剤は多層構成として
第１層11をn1＝1.49,第２層12をn2＝1.52、中心部13をn
i＝1.54とした場合の表面反射は 透明基材から第１層への入光: ０％ 第１層から第２層への入光 :0.0099％ 第２層から中心部への入光 :0.0043％ 中心部から第２層への出光 :0.0043％ 第２層から第１層への出光 :0.0099％ 第１層から透明基材への出光: ０％ となり、これらの損失を総合すると 0.0283％ となる。従って、上記の構成をとることにより光の反射
損失を著しく減少させることが可能である。On the other hand, in FIG. 2 (b), polymethyl methacrylate is used for the transparent base material, and the diffusing agent has a multi-layered structure in which the first layer 11 has n 1 = 1.49, the second layer 12 has n 2 = 1.52, 13 to n
When i = 1.54, the surface reflection is as follows: light entering from transparent substrate to first layer: 0% light entering from first layer to second layer: 0.0099% light entering from second layer to center: 0.0043 % Light emission from the center to the second layer: 0.0043% Light emission from the second layer to the first layer: 0.0099% Light emission from the first layer to the transparent substrate: 0%, and the total loss is 0.0283%. Become. Therefore, it is possible to significantly reduce the reflection loss of light by adopting the above configuration.
ここで示したのはモデル的な例であり、実際には光の
入射角等を考慮する必要があるが、（ここでは複雑にな
るので省略する。）同様に反射損失を減少させることが
できる。光拡散シート全体では光の反射損失は例に示す
ものの集合となるので、反射損失の減少量も大きな差と
なって現れる。This is a model example, and it is actually necessary to consider the incident angle of light and the like. However, the reflection loss can be similarly reduced (it is omitted here because it becomes complicated here). . In the entire light diffusion sheet, the reflection loss of light is a set of those shown in the example, so that the amount of reduction in reflection loss also appears as a large difference.
上記の原理は、反射防止膜や光ファイバー等に応用さ
れているものであるが、本発明は種々の検討をして光拡
散シート、特に透過型投影スクリーンに上記の原理を応
用した結果、後述するような特有の効果を奏する光拡散
シートを提供するに到ったものである。The above-mentioned principle is applied to an antireflection film or an optical fiber, etc., but the present invention is described below as a result of applying the above-described principle to a light diffusing sheet, especially a transmission type projection screen after various studies. Thus, the invention has provided a light diffusion sheet exhibiting such a specific effect.
本発明の光拡散シートに使用する拡散剤の形状は球状
のものの他、いかなるものでもよく、特定の形状に限定
する必要はない。また、中心部とは厳密に中心である必
要はなく、多少偏在していても実用上は問題ない。The shape of the diffusing agent used in the light diffusing sheet of the present invention is not limited to a spherical shape but may be any shape, and need not be limited to a specific shape. The center does not have to be strictly at the center, and there is no problem in practical use even if the center is slightly uneven.
透明基材に用いる材料としては、ポリメチルメタクリ
レート、ポリスチレン、ポリカーボネート、ポリエステ
ル、ポリオレフィン、ポリ塩化ビニル、エポキシ等の熱
可塑性樹脂、熱硬化性樹脂の他、ガラス等の無機透明材
料も使用できる。樹脂を使用する場合は、上記のホモポ
リマーの他、各樹脂のコポリマーも使用できる。As a material used for the transparent substrate, a thermoplastic resin such as polymethyl methacrylate, polystyrene, polycarbonate, polyester, polyolefin, polyvinyl chloride, epoxy or the like, a thermosetting resin, or an inorganic transparent material such as glass can be used. When a resin is used, a copolymer of each resin can be used in addition to the above homopolymer.
拡散剤は以下に示す方法により作製したものが使用で
きる。As the diffusing agent, those produced by the following method can be used.
（ａ） 屈折率の異なるモノマーの共重合において、重
合の進行に従って徐々に一方のモノマーの量を増加させ
ることにより、屈折率が多層状に、あるいは連続的に変
化したビーズを作製する。例えば、スチレン（ｎ＝1.
6）／メチルメタクリレート（ｎ＝1.49）の乳化重合に
おいて、重合開始時はスチレン主体の重合を行い、徐々
にメチルメタクリレートの割合を増加させていく。これ
により、中心部の屈折率が1.6で、最外縁部の屈折率が
ほぼ1.49の拡散剤が得られる。(A) In the copolymerization of monomers having different refractive indexes, by gradually increasing the amount of one monomer as the polymerization proceeds, beads having a multilayer or continuous refractive index are produced. For example, styrene (n = 1.
6) In the emulsion polymerization of methyl methacrylate (n = 1.49), styrene-based polymerization is performed at the start of polymerization, and the ratio of methyl methacrylate is gradually increased. As a result, a diffusing agent having a refractive index of 1.6 at the center and a refractive index of about 1.49 at the outermost edge is obtained.
（ｂ） 重合開始剤を含んだビーズを屈折率の異なるモ
ノマー蒸気中に入れて、モノマーで飽和する前に重合を
行い、屈折率のグラデーションのついたビーズを作製す
る。例えば、ポリカーボネートのビーズ中に増感剤を入
れ、メチルメタクリレートのモノマー蒸気中に放置した
後、UVを照射してメチルメタクリレートモノマーを硬化
させる。(B) Beads containing a polymerization initiator are put into monomer vapors having different refractive indices, and polymerized before being saturated with a monomer, to produce beads with a refractive index gradation. For example, a sensitizer is placed in polycarbonate beads, left in a methyl methacrylate monomer vapor, and then irradiated with UV to cure the methyl methacrylate monomer.
（ｃ） その他、ガラスビーズのイオン交換をする方
法、ビーズの表面を屈折率の異なる材料でコーティング
する方法等が使用できる。(C) In addition, a method of performing ion exchange of glass beads, a method of coating the surfaces of beads with materials having different refractive indexes, and the like can be used.
本発明において、透明基材に熱可塑性樹脂を使用し、
拡散剤として透明基材に対して非相溶性のガラス等の無
機物質または架橋した共重合体を使用して押し出し成形
等の熱成形加工を行うと、冷却時の熱可塑性樹脂の収縮
に対して拡散剤の体積変化が少ないので、光拡散シート
の表面に拡散剤あるいは拡散剤を核とする熱可塑性樹脂
からなる凹凸形状を形成することができる。このことは
光拡散シートの表面部分での拡散が行える点で、拡散効
率の向上、画像の解像性の向上に有効である。In the present invention, using a thermoplastic resin for the transparent substrate,
When performing thermoforming such as extrusion using an inorganic substance such as glass or a crosslinked copolymer incompatible with a transparent substrate as a diffusing agent, shrinkage of the thermoplastic resin upon cooling Since the volume change of the diffusing agent is small, an uneven shape made of the diffusing agent or a thermoplastic resin having the diffusing agent as a nucleus can be formed on the surface of the light diffusing sheet. This is effective in improving the diffusion efficiency and the resolution of an image because the light can be diffused in the surface portion of the light diffusion sheet.
また、光拡散シートの表面（観察側）または裏面（光
源側）に表面拡散性のシートをラミネートする等の方法
により、表面の凹凸形状の大きさを裏面の凹凸形状の大
きさと異なるようにすること、特に表面の凹凸より裏面
の凹凸形状を大きくすることは、入射する光源光の部分
的な強弱を平均化して、画面のギラツキを生じなくする
ことができるので有効である。Also, the size of the irregularities on the front surface is made different from the size of the irregularities on the back surface by, for example, laminating a surface diffusible sheet on the front surface (observation side) or the back surface (light source side) of the light diffusion sheet. In particular, it is effective to make the unevenness of the back surface larger than the unevenness of the front surface because the intensity of the incident light source can be averaged to prevent glare on the screen.
本発明の光拡散シートを透過型投影スクリーンとして
使用する場合には、垂直方向と水平方向の拡散を比較す
ると、水平方向の拡散がより大きいことが要求されるの
で、水平方向に光を拡散するレンチキュラーレンズを併
用することも有効である。When the light diffusion sheet of the present invention is used as a transmission type projection screen, when the diffusion in the vertical direction and the diffusion in the horizontal direction are compared, it is required that the diffusion in the horizontal direction is larger, so that the light is diffused in the horizontal direction. It is also effective to use a lenticular lens together.
（作用） 上記のように構成した本発明の光拡散シートは、最外
縁部の屈折率が透明基材とほぼ同じで、中心部に向かっ
て屈折率が連続的に、あるいは微小な屈折率の差をもっ
て段階的に増加する拡散剤を透明基材中に分散している
ために、光源光の反射損失を少なくすることができる。(Function) In the light diffusion sheet of the present invention configured as described above, the refractive index at the outermost edge is almost the same as that of the transparent base material, and the refractive index is continuously or gradually reduced toward the center. Since the diffusing agent that gradually increases with a difference is dispersed in the transparent substrate, the reflection loss of the light from the light source can be reduced.
これにより、本発明の光拡散シートを透過型投影スク
リーンに使用した場合には、観察者側に投影される有効
な光量が増加して同一の光学系を使用した場合でも輝度
が高く、外光に対してもコントラスト劣化が少なくでき
る他、不要な散乱光が発生しないために、画像の濁りが
改善されて透明感のある画像を得ることができる。As a result, when the light diffusion sheet of the present invention is used for a transmission type projection screen, the effective light amount projected to the observer increases, and even when the same optical system is used, the luminance is high and the external light is high. In addition, the contrast deterioration can be reduced, and unnecessary scattered light is not generated, so that the turbidity of the image is improved and a transparent image can be obtained.
（実施例） 以下に実施例をあげて、更に具体的に本発明を説明す
る。(Example) Hereinafter, the present invention will be described more specifically with reference to examples.
第３図は本発明の光拡散シートの第１の実施例を示す
図である。FIG. 3 is a view showing a first embodiment of the light diffusion sheet of the present invention.
屈折率1.52の透明なアクリル系樹脂中にスチレン／メ
チルメタクリレートの乳化重合により作製した、最外縁
部屈折率1.52、中心部屈折率1.57、直径10μｍの架橋ビ
ーズを９パーツ混練し、押し出し成形してシートとし
た。次いでこのシートを180℃に加熱したレンチキュラ
ー金型によりプレス成形して、一方の表面にレンチキュ
ラー形状14を有する光拡散シートを作製した。9 parts of crosslinked beads with a refractive index of 1.52 at the outermost edge, a refractive index of 1.57 at the center, and a diameter of 10 μm produced by emulsion polymerization of styrene / methyl methacrylate in a transparent acrylic resin with a refractive index of 1.52 are kneaded and extruded. Sheet. Next, this sheet was press-formed with a lenticular mold heated to 180 ° C. to produce a light diffusion sheet having a lenticular shape 14 on one surface.
この光拡散シートをフレネルレンズシートと組み合わ
せ透過型投影スクリーンとして使用したところ、同じ透
明基材に無アルカリガラス（屈折率1.55）7.5パーツを
混練した通常の透過型投影スクリーンと比較して透明感
のある画像が得られ、座視、立視にかかわらず明るく、
コントラストの高い良好な画質が得られた。When this light diffusion sheet was used as a transmission type projection screen in combination with a Fresnel lens sheet, the transparency was higher than that of a normal transmission type projection screen in which 7.5 parts of alkali-free glass (refractive index: 1.55) were kneaded on the same transparent substrate. A certain image is obtained, and it is bright regardless of sitting or standing,
Good image quality with high contrast was obtained.
第４図は本発明の光拡散シートの第２の実施例を示す
図である。FIG. 4 is a view showing a second embodiment of the light diffusion sheet of the present invention.
架橋ポリエチレンビーズをメチルメタクリレートモノ
マーの蒸気中にさらし、UVを照射して作製した最外縁屈
折率1.57、中心部屈折率1.59、粒子径15〜100μｍ（中
心粒子径30μｍ）の拡散剤ビーズ4.5パーツを屈折率1.5
7のポリメチルメタクリレート系樹脂に混練した後、第
５図のごとく押し出し機18で押し出し、一対の加熱ロー
ル19、20間で押圧しながら、部分的に架橋させた架橋塩
化ビニル樹脂を主成分とした微小凹凸形状17を有するフ
ィルム（厚み80μｍ）16を熱ラミネートし、透過型投影
スクリーン用の光拡散シート21を得た。この光拡散シー
トのレンチキュラーレンズ表面は粗い球状凹凸形状15を
有し、他方の面は細かい凹凸形状17を有していた。この
光拡散シートをレンチキュラーレンズ面をフレネルレン
ズと対向するように配置してプロジェクションテレビに
装着し、画像を観察したところ透明感があり、ギラツキ
がなく、かつ座視、立視にかかわらず良好が画質が得ら
れた。Cross-linked polyethylene beads are exposed to the vapor of methyl methacrylate monomer and irradiated with UV to produce 4.5 parts of diffusing agent beads with a refractive index of 1.57 at the outermost edge, a refractive index of 1.59 at the center, and a particle diameter of 15-100 μm (central particle diameter of 30 μm) Refractive index 1.5
After being kneaded with the polymethyl methacrylate resin of No. 7, the mixture was extruded by an extruder 18 as shown in FIG. 5, and while being pressed between a pair of heating rolls 19 and 20, a partially cross-linked cross-linked vinyl chloride resin was used as a main component. A film 16 (thickness: 80 μm) having the fine irregularities 17 was thermally laminated to obtain a light diffusion sheet 21 for a transmission type projection screen. The lenticular lens surface of this light diffusion sheet had a rough spherical uneven shape 15, and the other surface had a fine uneven shape 17. This light diffusion sheet was placed on a projection TV with the lenticular lens surface facing the Fresnel lens, and when the image was observed, there was a sense of transparency, there was no glare, and it was good regardless of sitting or standing. Image quality was obtained.
（発明の効果） 本発明の光拡散シートは以上説明したように構成され
ているので、光源光の反射による損失が少なくなり、拡
散効率がよく、明るくコントラストの良好な画像が得ら
れ、さらに不要な散乱光が減少するので、画像の濁りが
なくなり、透明感のある良好な画質が得られるという効
果を有する。(Effect of the Invention) Since the light diffusion sheet of the present invention is configured as described above, the loss due to the reflection of the light from the light source is reduced, the diffusion efficiency is good, and a bright and high-contrast image is obtained, which is further unnecessary. Since the amount of scattered light is reduced, turbidity of the image is eliminated, and an effect of obtaining a transparent and good image quality is obtained.
第１図は本発明の光拡散シートの部分拡大図、 第２図は本発明の原理を説明するための図、第３図は本
発明の光拡散シートの第１の実施例を示す拡大断面図、
第４図は本発明の光拡散シートの第２の実施例を示す拡
大断面図、第５図は本発明の光拡散シートの第２実施例
の製造方法を説明する図である。 １……透明基材、２……拡散剤、３……最外縁部、４…
…中心部、５……微小な屈折率の差を有する層、６……
連続的に屈折率の変化する部分、11……拡散剤の第１
層、12……拡散剤の第２層、13……中心部、14……レン
チキュラーレンズ、15、17……凹凸形状。FIG. 1 is a partially enlarged view of a light diffusion sheet of the present invention, FIG. 2 is a view for explaining the principle of the present invention, and FIG. 3 is an enlarged cross section showing a first embodiment of the light diffusion sheet of the present invention. Figure,
FIG. 4 is an enlarged sectional view showing a second embodiment of the light diffusion sheet of the present invention, and FIG. 5 is a view for explaining a method of manufacturing the second embodiment of the light diffusion sheet of the present invention. 1 ... transparent substrate, 2 ... diffusing agent, 3 ... outermost edge, 4 ...
... Center part, 5 ... Layer having a small difference in refractive index, 6 ...
The part where the refractive index changes continuously, 11...
Layer 12, 12 second layer of diffusing agent, 13 center part, 14 lenticular lens, 15, 17 uneven shape.
Claims (5)
n0＜niなる屈折率niであって、最外縁部から中心部に向
かって屈折率がn0からniまで連続的あるいは段階的に増
加してなる光拡散剤を、屈折率n0にほぼ等しい透明基材
中に分散してなることを特徴とする光拡散シート。1. The refractive index of the outermost edge is n 0 , and the refractive index of the center is
n 0 <n a i becomes a refractive index n i, a light diffusing agent having a refractive index toward the center portion is increased continuously or stepwise from n 0 to n i from the outermost edge, the refractive index n A light diffusion sheet characterized by being dispersed in a transparent substrate substantially equal to 0 .
基材が熱可塑性樹脂であることを特徴とする請求項１記
載の光拡散シート。2. The light diffusion sheet according to claim 1, wherein the light diffusion agent is a non-thermoplastic resin, and the transparent substrate is a thermoplastic resin.
レンチキュラーレンズ形及び／又は表面光拡散要素を有
することを特徴とする請求項１又は２記載の光拡散シー
ト。3. The front and / or back surface of the light diffusion sheet,
3. The light diffusing sheet according to claim 1, comprising a lenticular lens shape and / or a surface light diffusing element.
光拡散剤及び／又は光拡散剤を核とする熱可塑性樹脂か
らなる凹凸形状が設けられていることを特徴とする請求
項１、２又は３記載の光拡散シート。4. The light diffusing sheet has a front surface and / or a back surface,
4. The light diffusing sheet according to claim 1, wherein the light diffusing sheet is provided with an uneven shape made of a light diffusing agent and / or a thermoplastic resin having the light diffusing agent as a nucleus.
の大きさが、該光拡散シートの裏面に設けられた凹凸形
状の大きさと異なることを特徴とする請求項４記載の光
拡散シート。5. The light diffusion sheet according to claim 4, wherein the size of the unevenness provided on the front surface of the light diffusion sheet is different from the size of the unevenness provided on the back surface of the light diffusion sheet. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27395288A JP2657536B2 (en) | 1988-10-29 | 1988-10-29 | Light diffusion sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27395288A JP2657536B2 (en) | 1988-10-29 | 1988-10-29 | Light diffusion sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02120702A JPH02120702A (en) | 1990-05-08 |
| JP2657536B2 true JP2657536B2 (en) | 1997-09-24 |
Family
ID=17534857
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27395288A Expired - Fee Related JP2657536B2 (en) | 1988-10-29 | 1988-10-29 | Light diffusion sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2657536B2 (en) |
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1988
- 1988-10-29 JP JP27395288A patent/JP2657536B2/en not_active Expired - Fee Related
Cited By (2)
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| KR101134962B1 (en) * | 2007-02-19 | 2012-04-09 | 산요가세이고교 가부시키가이샤 | Particle having multilayer structure |
| JP2010077243A (en) * | 2008-09-25 | 2010-04-08 | Jsr Corp | Optical diffusing particle, method for producing the same, optical diffusing particle composition, and optical diffusing film |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02120702A (en) | 1990-05-08 |
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