JPH06281934A - Back light - Google Patents
Back lightInfo
- Publication number
- JPH06281934A JPH06281934A JP6009730A JP973094A JPH06281934A JP H06281934 A JPH06281934 A JP H06281934A JP 6009730 A JP6009730 A JP 6009730A JP 973094 A JP973094 A JP 973094A JP H06281934 A JPH06281934 A JP H06281934A
- Authority
- JP
- Japan
- Prior art keywords
- light
- sheet
- guide plate
- light guide
- straight line
- 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.)
- Granted
Links
Landscapes
- Light Guides In General And Applications Therefor (AREA)
- Liquid Crystal (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、透過型又は、半透過型
パネルを背面より照射するパネル用バックライトに関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight for a panel which illuminates a transmissive or semi-transmissive panel from the back side.
【０００２】[0002]
【従来の技術】近時、ラップトップ型又は、ブック型の
ワ−ドプロセッサ−やコンピュ−タ等の表示装置とし
て、薄型でしかも見易いバックライト機構を有する液晶
表示装置が用いられている。このようなバックライトに
は、図１に示すように透光性の導光板の一端部に、蛍光
管のような線状光源を併設するエッジライト方式がよく
用いられる。このエッジライト方式の場合、図２に示す
ように、導光板の一方の面に光拡散性エレメントをドッ
ト状またはストライプ状に形成し、その面のほぼ全面を
鏡面反射板又は光拡散反射シ−トで覆い、導光板の反対
側の面（光の出光面）を光拡散シ−ト（図２中２）で覆
うように配置されたものが多い。2. Description of the Related Art Recently, a liquid crystal display device having a backlight mechanism which is thin and easy to see has been used as a display device for a laptop or book type word processor, a computer or the like. For such a backlight, an edge light system is often used in which a linear light source such as a fluorescent tube is provided at one end of a light-transmitting light guide plate as shown in FIG. In the case of this edge light system, as shown in FIG. 2, a light diffusing element is formed in a dot shape or a stripe shape on one surface of the light guide plate, and almost the entire surface is a specular reflection plate or a light diffusion reflection sheet. In many cases, it is arranged so that the surface opposite to the light guide plate (light emitting surface) is covered with a light diffusion sheet (2 in FIG. 2).
【０００３】特に近時、バックライトがバッテ−リ−駆
動されるようになり消費電力−輝度変換効率のより一層
の向上が望まれおり、バックライトの発光面に同一面に
微細な間隔で直線状頂稜をもつプリズム又は凸部頂稜
が、前記頂稜がほぼ平行となる状態で多数有する透光性
材料からなるシ−トを配し、バックライトから出光する
光に指向性を付与し出光面の法線方向の輝度を増加させ
ることが提案されている。しかし、前記シ−ト自体は光
拡散性が少ないため、導光板に形成した光拡散性エレメ
ントを隠蔽する性能が十分でなく、シ−トを通して光拡
散性エレメントの形状が透視される問題があった。この
ように光拡散性エレメントの形状が透視されると、均一
な面状発光を得る点で好ましくない。Particularly in recent years, the backlight is driven by battery, and further improvement of power consumption-luminance conversion efficiency is desired, and a straight line is formed on the same surface of the backlight at a minute interval. A prism or convex ridge having a curved ridge is provided with a sheet made of a translucent material having a large number of ridges in a state where the ridges are substantially parallel to each other to give directivity to the light emitted from the backlight. It has been proposed to increase the brightness in the direction normal to the light exit surface. However, since the sheet itself has a low light diffusing property, the performance of hiding the light diffusing element formed on the light guide plate is not sufficient, and there is a problem that the shape of the light diffusing element is seen through the sheet. It was When the shape of the light diffusing element is seen through in this manner, it is not preferable in that uniform planar light emission is obtained.
【０００４】この問題を解決するために、前記シ−ト自
体に光拡散性物質を塗布したり、シ−ト面をランダムな
粗面にするなどして光拡散性を付与することが考えられ
ているが、このような方法は、シートの持つバックライ
トから出射する光に指向性を付与する性質が低下し従っ
て出光面の輝度が低下する問題があった。In order to solve this problem, it is considered that the sheet itself is coated with a light diffusing substance or the sheet surface is made to be a random rough surface so as to give the light diffusing property. However, such a method has a problem that the property of imparting directivity to the light emitted from the backlight of the sheet is deteriorated and thus the brightness of the light emitting surface is decreased.
【０００５】また、前記シ−トとは別の光拡散性シ−ト
を積層して用いる方法も提案されているが、このような
形態にすると光拡散性シ−ト自体の厚さ分だけバックラ
イトが厚くなり、バックライトの薄型化の要求が満たさ
れないばかりでなく出光面の輝度の面でも必ずしも好ま
しいものではない。A method of stacking and using a light diffusing sheet other than the above-mentioned sheet has also been proposed. However, in such a form, only the thickness of the light diffusing sheet itself is used. Not only is the thickness of the backlight increased, the requirement for thinning the backlight is not satisfied, but also the brightness of the light emitting surface is not always preferable.
【０００６】また、前記導光板上に形成する光拡散性エ
レメントどうしの間隔を例えば５０μm 以下と狭くする
と、前記したような個々の光拡散性エレメントは識別が
困難な程度にすることが可能であるが、このような状態
に光拡散性エレメントを形成するのは技術的にも困難で
ある。If the distance between the light diffusing elements formed on the light guide plate is narrowed to, for example, 50 μm or less, the individual light diffusing elements as described above can be made difficult to identify. However, it is technically difficult to form the light diffusing element in such a state.
【０００７】[0007]
【発明が解決しようとする課題】本発明の目的は、消費
電力−輝度変換効率が高く、かつ薄型なバックライトを
安価に提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a thin backlight which has high power consumption-luminance conversion efficiency and is thin.
【０００８】[0008]
【課題を解決するための手段】本発明者等は、上述の点
につき種々の検討を行った結果、バックライトの出光面
の光の指向性を向上させるシートを、ある条件を満たす
ように導光板面上に配置することにより、導光板面に形
成した光拡散性エレメントが隠蔽されて透視されず、し
かも光の指向性が強くなり、実質的に出光面に降ろした
法線方向近傍に対して、消費電力−輝度変換効率が高く
比較的薄型のバックライトとなることを見出し本発明を
完成した。As a result of various studies on the above points, the inventors of the present invention have led a sheet that improves the directivity of the light on the light emitting surface of the backlight so as to satisfy certain conditions. By arranging on the light plate surface, the light diffusing element formed on the light guide plate surface is hidden and not seen through, and the directivity of the light becomes stronger, and substantially in the vicinity of the normal direction dropped to the light exit surface. As a result, they have found that the backlight has high power consumption-luminance conversion efficiency and is relatively thin, and thus completed the present invention.
【０００９】即ち本発明は、透光性材料からなる導光板
の一方の広い面に、ドット状又はストライプ状に光拡散
性エレメントを形成し、前記導光板の少なくとも一側面
端部にこれに近接した線状光源を有するパネル用バック
ライトに於いて、導光板の出光面側に、微細な間隔で直
線状頂稜をもつプリズム又は同凸状部が、前記頂稜がほ
ぼ平行となる状態で同一面に多数有する透光性材料から
なるシ−トを、前記直線状頂稜が、中心が最短距離で隣
合うドット状の光拡散性エレメントの中心どうしを結ぶ
仮想直線、又は前記ストライプ状の光拡散性エレメント
の中心線どうしを最短距離で結ぶ仮想直線と交差する状
態に１枚以上配置したパネル用バックライトに関するも
のである。That is, according to the present invention, a light diffusing element is formed in a dot shape or a stripe shape on one wide surface of a light guide plate made of a translucent material, and at least one side surface end portion of the light guide plate is close to this. In a backlight for a panel having a linear light source, a prism or a convex portion having linear apexes at minute intervals is provided on the light emitting surface side of the light guide plate in a state where the apexes are substantially parallel to each other. A sheet made of a translucent material having a large number on the same plane, the linear top edge is a virtual straight line connecting the centers of dot-shaped light diffusing elements adjacent to each other at the shortest distance between the centers, or the striped shape. The present invention relates to a panel backlight in which one or more panels are arranged in a state of intersecting a virtual straight line connecting the center lines of the light diffusing elements with the shortest distance.
【００１０】次に本発明を図面に基づいて更に詳述す
る。Next, the present invention will be described in more detail with reference to the drawings.
【００１１】図３は、本発明の一実施態様の斜視図であ
り、図４は、エッジライト方式のバックライトの一例を
示す断面図である。図中１は導光板であり、光を効率よ
く通過させる物質であればよく、石英、ガラス、透光性
の天然又は合成樹脂、例えばアクリル系樹脂等で構成さ
れる。FIG. 3 is a perspective view of an embodiment of the present invention, and FIG. 4 is a sectional view showing an example of an edge light type backlight. In the figure, reference numeral 1 denotes a light guide plate, which may be any substance that allows light to pass efficiently, and is made of quartz, glass, translucent natural or synthetic resin such as acrylic resin.
【００１２】導光板の一方の広い面に光拡散性エレメン
ト（図中６）を形成するには、光を拡散させる作用があ
る物質例えばシリカ、硫酸バリウム、炭酸カルシウム、
チタンホワイト、ガラスビ−ズ、樹脂ビ−ズ、気泡等を
含んだ塗料、印刷インキ等の光拡散性物質をスクリ−ン
印刷等の方法で導光板面上にドット状又はストライプ状
に印刷する方法、又は導光板の表面をドット状又はスト
ライプ状に粗面化する方法、導光板の表面に小孔を開け
るか小突起を形成する方法、導光板を階段状に欠削する
方法などの方法がある。ここで言うドット状の光拡散性
エレメントは、例えばこれをスクリ−ン印刷する場合、
円形、角型などの形状のものであり、又、ストライプ状
の光拡散性エレメントは、直線状に形成したものであ
る。In order to form a light diffusing element (6 in the figure) on one wide surface of the light guide plate, a substance having a function of diffusing light, such as silica, barium sulfate, calcium carbonate,
A method of printing a light diffusing substance such as titanium white, glass beads, resin beads, paints containing bubbles, printing ink, etc. on the light guide plate surface in a dot shape or a stripe shape by a screen printing method or the like. Or, a method of roughening the surface of the light guide plate into a dot shape or a stripe shape, a method of forming a small hole or a small protrusion on the surface of the light guide plate, a method of notching the light guide plate in a stepwise manner, etc. is there. The dot-shaped light diffusing element referred to here is, for example, in the case of screen printing the same.
The light diffusing element has a circular shape, a rectangular shape, or the like, and the stripe-shaped light diffusing element is formed in a linear shape.
【００１３】本発明で、導光板上に光拡散性エレメント
を形成するに際し仮想される直線とは、光拡散性エレメ
ントがドット状である場合は隣接したドットの中心が実
質的に最短距離に位置するドットの中心同士を結ぶに際
し仮想される直線（仮想直線）であり、光拡散性エレメ
ントがストライプ状である場合はストライプの中心線を
最短距離で結ぶに際し仮想される直線である。この様な
仮想線は、通常、導光板に光拡散性エレメントを形成す
る際に、導光板面に形成する光拡散性エレメントの位置
決めの基準ともなる。In the present invention, the imaginary straight line when forming the light diffusing element on the light guide plate means that when the light diffusing element has a dot shape, the centers of the adjacent dots are located at the substantially shortest distance. Is a virtual line (virtual straight line) when connecting the centers of the dots, and when the light diffusing element has a stripe shape, it is a virtual line when connecting the center lines of the stripes at the shortest distance. Such an imaginary line usually serves as a reference for positioning the light diffusing element formed on the surface of the light guide plate when the light diffusing element is formed on the light guide plate.
【００１４】図５〜９に、導光板上の光拡散性エレメン
ト形成の例を示した。図中６は光拡散性物質などで構成
される光拡散性エレメントで、７は前記した仮想直線を
示す。これらの仮想直線は通常は図５，図８のように縦
横直交し、各々に実質的に平行の位置に、即ち、相隣る
光拡散性エレメントの中心を最短距離で結ぶ仮想直線
（図中７）が正方形を形成する位置に、形成すること
が、製造上の容易さの面で一般的であるが、図６のよう
な配置、即ち、相隣る光拡散性エレメントの中心を最短
距離で結ぶ仮想直線（図中７）が正三角形を形成する位
置に形成することも、同様の理由で可能である。5 to 9 show examples of forming the light diffusing element on the light guide plate. In the figure, 6 is a light diffusing element composed of a light diffusing substance, and 7 is the above-mentioned virtual straight line. These virtual straight lines are normally orthogonal to each other in the vertical and horizontal directions as shown in FIGS. 5 and 8, and are substantially parallel to each other, that is, a virtual straight line connecting the centers of adjacent light diffusing elements with the shortest distance (in the drawings). 7) is generally formed in a position where a square is formed, from the viewpoint of ease of manufacturing, the arrangement as shown in FIG. 6, that is, the shortest distance from the center of adjacent light diffusing elements It is possible to form an imaginary straight line (7 in the figure) connected by the line at a position forming an equilateral triangle for the same reason.
【００１５】本発明で用いる後述の透光性材料からなる
シ−トの直線状頂稜と交差する直線はこのような線であ
る。尚、図５のように仮想線が直交した場合は、仮想線
と後述の透光性材料からなるシ−トの前記直線状頂稜と
が９０度又は０度の角度で交差する場合は後述する本発
明の効果があまり得られない。The straight line intersecting with the linear apex of the sheet made of a translucent material, which will be described later, used in the present invention is such a line. Incidentally, when the imaginary lines are orthogonal to each other as shown in FIG. 5, when the imaginary lines and the above-mentioned linear apexes of the sheet made of a translucent material described later intersect at an angle of 90 degrees or 0 degrees, the description will be made later. The effect of the present invention is not obtained so much.
【００１６】又、導光板の表面に塗布又は欠削などの方
法で図７のようにストライプ状に光拡散性エレメントを
形成した場合は、通常の状態では後述の線状光源とほぼ
平行のストライプが形成された状態となることが多く、
本発明ではこのようなストライプの中心線どうしを最短
距離で結ぶに際し仮想される直線（図中７）と後述の透
光性材料からなるシ−トの直線状頂稜とを交差させる。Further, when the light diffusing element is formed in a stripe shape on the surface of the light guide plate by a method such as coating or chipping as shown in FIG. 7, in a normal state, a stripe substantially parallel to the linear light source described later is formed. Is often formed,
In the present invention, a straight line (7 in the figure) that is imaginary when connecting the center lines of such stripes to each other at the shortest distance is made to intersect with a straight apex of a sheet made of a translucent material described later.
【００１７】図９は角型のドットを、図面における横方
向（図中の線分７に沿って）に等間隔に配置した例であ
るが、この場合、この相隣る光拡散性エレメントの中心
を最短距離で結ぶ線分が仮想直線（図中７）である。FIG. 9 shows an example in which square dots are arranged at equal intervals in the lateral direction (along line segment 7 in the drawing) in the drawing. In this case, the adjacent light diffusing elements are arranged. A line segment connecting the centers with the shortest distance is a virtual straight line (7 in the figure).
【００１８】又、前記仮想される直線の態様は、後述の
透光性材料からなるシ−トを通して光拡散性エレメント
の形状を、発光面全域に渡って等しく人間の目では認識
し難くするために実質的に平行な状態にすることが特に
好ましい。尚、全ての前記仮想される直線が１方向に対
してのみ平行である必要はなく、図５のように平行な方
向が２方向の場合、図６のように３方向の場合でも良
い。Further, the imaginary straight line mode makes it difficult for the human eye to recognize the shape of the light diffusing element evenly over the entire light emitting surface through a sheet made of a light transmitting material described later. It is particularly preferable to make the state substantially parallel to. It is not necessary that all the virtual lines are parallel to only one direction, and the parallel directions may be two directions as shown in FIG. 5 or three directions as shown in FIG.
【００１９】このような導光板上に仮想される実質的に
平行な線の間隔は０．０１mm〜５mmの範囲が好ましい
が、３mm以上になると光拡散性エレメントの形状そのも
のが前記シ−トを通して透けて見え易くなり、また、
０．０３mm以下になると製造上の歩留まりが極端に悪化
するので、好ましくは０．０３mm〜２mmの範囲である。The distance between virtually parallel lines imaginary on such a light guide plate is preferably in the range of 0.01 mm to 5 mm, but when it is 3 mm or more, the shape of the light diffusing element itself passes through the sheet. It is easy to see through, and again
If the thickness is 0.03 mm or less, the manufacturing yield is extremely deteriorated, so the range is preferably 0.03 mm to 2 mm.
【００２０】本発明で上記した透光性材料からなるシ−
トの直線状頂稜と仮想直線との交差角度は１０〜７０度
が導光板の光拡散性エレメントの隠蔽する上で好まし
い。さらに光拡散性エレメントのパターンによってその
好ましい範囲が異なる。即ち、仮想直線が正方形（図
５，図８）を形成するもの、光拡散性エレメントがスト
ライプ状（図７）、角型（図９）のものについては、前
記交差角度は２０〜７０度、さらに４５度近辺が好まし
い。又、仮想直線が正三角形（図６）を形成するものに
ついては、前記交差角度は１０〜５０度、さらに３０度
近辺が好ましい。A sheath made of the translucent material described above in the present invention.
It is preferable that the intersecting angle between the straight apexes of the gland and the virtual straight line is 10 to 70 degrees in order to conceal the light diffusing element of the light guide plate. Further, the preferable range varies depending on the pattern of the light diffusing element. That is, for a virtual straight line forming a square (FIGS. 5 and 8), a light diffusing element having a stripe shape (FIG. 7), and a square shape (FIG. 9), the intersection angle is 20 to 70 degrees. Further, the vicinity of 45 degrees is preferable. When the virtual straight line forms an equilateral triangle (FIG. 6), the intersection angle is preferably 10 to 50 degrees, and more preferably around 30 degrees.
【００２１】４は線状光源で、好ましい態様としては、
導光板の端部に光が入光するための間隙（スリット）を
有するＡｇ、Ａｌなどの鏡面の反射シ−トまたはポリエ
チレンテレフタレート（ＰＥＴ）にＢａＳＯ4 、ＴｉＯ
2 、気泡などで光拡散性を付与した光拡散反射シ−トで
形成された光反射器５で、線状光源の光源面とある幅の
間隙をもたせた状態で覆われており、例えば１灯式（片
側）、２灯式（両側）、又は３方、４方側等の導光板の
少なくとも一端面部に近接してその中心軸が導光板の端
面とほぼ平行となるように設置される。前記線状光源
は、蛍光管、タングステン白熱管、オプティカルロッ
ド、ＬＥＤを配列した物等があるが、蛍光管が好まし
く、省電力の面から、電極部を除く均一発光部の長さ
が、近接する導光板の端部の長さとほぼ等しいことが好
ましい。Reference numeral 4 is a linear light source, and in a preferred embodiment,
A light reflecting plate having a gap (slit) at the end of the light guide plate, such as a reflective sheet of Ag, Al, or the like, or a polyethylene terephthalate (PET) having a BaSO 4 , TiO 2
2. A light reflector 5 formed of a light diffusive reflection sheet provided with light diffusivity by bubbles or the like, and covered with a light source surface of the linear light source and a gap of a certain width. Light type (one side), two-lamp type (both sides), or three-sided, four-sided, etc. are installed in proximity to at least one end face portion of the light guide plate such that its central axis is substantially parallel to the end face of the light guide plate. . The linear light source may be a fluorescent tube, a tungsten incandescent tube, an optical rod, an LED array, or the like, but a fluorescent tube is preferable, and from the viewpoint of power saving, the length of the uniform light emitting section excluding the electrode section is close to each other. It is preferable that the length is substantially equal to the length of the end portion of the light guide plate.
【００２２】Ａｇ、Ａｌなどの鏡面の反射シ−トまたは
ＰＥＴにＢａＳＯ4 、ＴｉＯ2 、気泡などで光拡散性を
付与した光拡散反射シ−ト（図中３）は光拡散性エレメ
ントを形成した導光板の面のほぼ全面を覆うように配置
する。A specular reflection sheet such as Ag or Al or a light diffusion reflection sheet (3 in the figure) in which PET is provided with light diffusion properties by BaSO 4 , TiO 2 , bubbles and the like forms a light diffusion element. It is arranged so as to cover almost the entire surface of the light guide plate.
【００２３】図中１０又は１２は透光性材料からなるシ
−トで、同一面に微細な間隔で互いに平行な、例えば、
図１０に示したような直線状頂稜を持つプリズム、又は
図１１に示したような同じく凸状部が、前記頂稜がほぼ
平行になるように多数有するもので、導光板の出光面側
に、頂稜が外側（導光板と相対する面と反対側）になる
ように配置する。前記したプリズムの形状は図１０に示
した形状のものばかりでなく、その斜辺の長さが異なる
形状のものでも良い。In the figure, 10 or 12 is a sheet made of a translucent material, which is parallel to each other at a fine interval on the same surface, for example,
A prism having a linear apex as shown in FIG. 10 or a large number of similar convex portions as shown in FIG. 11 are provided so that the apices are substantially parallel to each other. Then, the apex is located outside (on the side opposite to the surface facing the light guide plate). The shape of the prism described above is not limited to the shape shown in FIG. 10, but may be a shape in which the length of the hypotenuse is different.
【００２４】本発明はこのようなシ−トを導光板の出光
面に配置する際、前記した頂稜が前記した導光板上に仮
想される直線と交差する状態に、１枚以上配置したこと
が特徴である。シ−トをこのように配置することによ
り、バックライトの出光面より出光した光の指向性を変
化させ、出光面に降ろした法線方向近傍に対する指向性
をより強くすることができ、消費電力−輝度変換効率が
高いバックライトが得られるばかりでなく、光拡散性エ
レメントのドット状又はストライプ状のその形状が透視
されないバックライトが得られる。According to the present invention, when arranging such a sheet on the light emitting surface of the light guide plate, one or more sheets are arranged in such a manner that the above-mentioned apex intersects a virtual line on the above-mentioned light guide plate. Is a feature. By arranging the sheet in this way, it is possible to change the directivity of the light emitted from the light emitting surface of the backlight, and to strengthen the directivity in the vicinity of the normal direction dropped on the light emitting surface, thereby reducing power consumption. Not only a backlight with high luminance conversion efficiency is obtained, but also a dot or stripe shape of the light diffusing element is not seen through.
【００２５】尚、必要に応じて更に従来の光拡散シ−ト
を配しても良いが、その場合の光拡散シ−トの光拡散性
は、本発明の効果により従来のものよりもかなり低くて
も良い。そのために光拡散シ−トの光線透過率が良好に
なり、光拡散シ−トを導光板と前記シ−トとの間に配し
ても輝度は殆ど低下しないばかりか光拡散シ−トの出光
面が入光面よりも粗面であるものを用いると輝度が更に
向上する。また、光拡散シ−トを前記シ−トの外側に配
しても前記シ−トによって得られた光の指向性はあまり
変化しない。If necessary, a conventional light diffusion sheet may be provided, but the light diffusion property of the light diffusion sheet in this case is considerably higher than that of the conventional one due to the effect of the present invention. It can be low. Therefore, the light transmittance of the light diffusing sheet becomes good, and even if the light diffusing sheet is arranged between the light guide plate and the sheet, the brightness is not substantially lowered and the light diffusing sheet has a light diffusing sheet. If the light emitting surface is rougher than the light entering surface, the brightness is further improved. Even if the light diffusion sheet is arranged outside the sheet, the directivity of the light obtained by the sheet does not change so much.
【００２６】本発明で用いる透光性材料からなるシ−ト
について更に詳述する。このシ−トの材料は透光性材料
からなるものであれば特に限定されないが、例えばメタ
クリル酸エステル、ポリカ−ボネイト、ポリ塩化ビニ
ル、ポリスチレン、ポリアミド、ポリエステル、ポリエ
チレン、ポリプロピレン、繊維素系樹脂、ガラス等であ
る。The sheet made of a translucent material used in the present invention will be described in more detail. The material of this sheet is not particularly limited as long as it is made of a translucent material. For example, methacrylic acid ester, polycarbonate, polyvinyl chloride, polystyrene, polyamide, polyester, polyethylene, polypropylene, fibrous resin, For example, glass.
【００２７】またシ−トの、出光面側に形成する互いに
平行な直線状頂稜の形状の一例としては図１０に示した
ように、光学的平面を２つ以上持ついわゆるプリズム状
のもので、前記２つの光学的平面が交わる頂稜（図中
８）は直線状で、同一面内には微細な間隔（図中Ｐ）で
互いに平行な多数の直線状プリズムが存在する状態のも
のである。シ−トに形成するこれら頂稜の頂角は実質的
に同じ形状の部分を持つもので、このことは、頂点を中
心として同一の条件で裁断した際にその頂角が実質的に
同じ角度を持つことを意味する。Further, as an example of the shape of the straight apexes parallel to each other formed on the light emitting surface side of the sheet, as shown in FIG. 10, it is a so-called prism shape having two or more optical planes. The apex ridge (8 in the figure) where the two optical planes intersect is linear, and a large number of linear prisms parallel to each other are present in the same plane at minute intervals (P in the figure). is there. The apex angles of these apexes formed on the sheet have portions of substantially the same shape. This means that the apex angles are substantially the same when cut under the same conditions with the apex as the center. Means to have.
【００２８】前記したシ−トの頂稜の頂角（図中９）は
７０〜１５０度であることが好ましい。前記頂稜のより
好ましい角度範囲は用いるシ−トの材料の屈折率および
用いる面状発光体の配光特性に依存する。例えば屈折率
の大なる材料（ポリカ−ボネイト、屈折率ｎ＝１．５
９）を用いた場合は、頂角は９０度以下になると面状発
光体から出光する光が出光面に降ろした法線方向近傍以
外にも出光してしまい、１１０度以上になると前記法線
方向近傍での光の指向性が減少するので、９０〜１１０
度であることが特に好ましい。The apex angle (9 in the figure) of the apex of the sheet is preferably 70 to 150 degrees. A more preferable angle range of the apex depends on the refractive index of the sheet material used and the light distribution characteristics of the planar light emitter used. For example, a material with a large refractive index (polycarbonate, refractive index n = 1.5
In the case of using 9), when the apex angle becomes 90 degrees or less, the light emitted from the planar light-emitting body also emits in a direction other than the vicinity of the normal direction dropped on the light emitting surface, and when it becomes 110 degrees or more, the normal line Since the directivity of light in the vicinity of the direction decreases, 90 to 110
It is particularly preferable that the degree is.
【００２９】本発明で用いる透光性シ−トの他の例とし
て、頂稜の形状が円弧を持った凸状（図１１中１１）が
ある。これらのシ−トの凸状の形状は凸状の頂稜がほぼ
平行となる状態であればよく特に限定されないが、頂稜
に垂直な断面が、円型の一部、楕円型の一部を形状、又
は波型、さらに、いわゆるカマボコ型などがある。この
ような頂稜の形状が凸状であると、凸状の形状そのもの
がレンズ作用を有しているので前述した光拡散性エレメ
ントの形状を歪めてさらにその形状を透視しにくくする
ので、更に好ましい。As another example of the translucent sheet used in the present invention, there is a convex shape (11 in FIG. 11) in which the shape of the apex has an arc. The convex shape of these sheets is not particularly limited as long as the convex apexes are substantially parallel, but the cross section perpendicular to the apexes is a part of a circle or a part of an ellipse. There is a shape or a wavy shape, and further, a so-called kamaboko shape and the like. If the shape of such a ridge is a convex shape, the convex shape itself has a lens action, so that the shape of the above-mentioned light diffusing element is distorted to make it difficult to see through the shape further. preferable.
【００３０】シ−トに形成した多数の頂稜と頂稜との間
隔は、表面から出光される光によってこれら頂稜同士の
間隔が人間の目で視認されにくくする上で、互いに隣り
合った頂稜と頂稜との間隔は１〜１０００が好ましく、
更に１０〜１０００μm であることがより好ましい。特
に本発明のバックライトを液晶ディスプレイに用いる場
合は、液晶の画素ピッチよりシ−トに形成した頂稜と頂
稜との間隔を狭く、特に３分の１以下（例えば、液晶の
画素ピッチが０．３mmの時はシ−トに形成した頂稜と頂
稜との間隔は０．３mm以下、特に好ましくは０．１mm以
下）にすることが、液晶ディスプレイの画素と本発明の
バックライトのシ−トに形成した多数の頂稜との間での
空間的モアレ現象を抑制する上で好ましい。The intervals between the numerous apexes formed on the sheet are adjacent to each other in order to make it difficult for human eyes to visually recognize the intervals between the apexes due to the light emitted from the surface. The distance between the ridges is preferably 1 to 1000,
More preferably, it is 10 to 1000 μm. In particular, when the backlight of the present invention is used in a liquid crystal display, the distance between the top ridges formed in the sheet is narrower than the pixel pitch of the liquid crystal, and in particular, one third or less (for example, the pixel pitch of the liquid crystal is When the distance is 0.3 mm, the distance between the top ridges formed on the sheet should be 0.3 mm or less, particularly preferably 0.1 mm or less). It is preferable for suppressing the spatial moire phenomenon between the plurality of crests formed on the sheet.
【００３１】そして前記頂稜部の厚さ（図１０中ｔ2）
は前記した頂稜の頂角又は凸状部の大きさ及び頂稜と頂
稜の間隔で決まるが、多数の直線状頂稜を微細な間隔で
互いに平行な位置関係に維持するための厚さ（図１０中
ｔ1）が必要で、このｔ1は光線透過率及びバックライト
の薄型化のためには薄い方が良いが、前記シ−トの製造
上の理由及び強度の点から、前記シ−トの総厚（図１０
中Ｔ）は１０〜３０００μm 、好ましくは５０〜１００
０μm が良い。また、同一面に形成する頂稜は、より効
果的には同一形状のものが良い。The thickness of the apex portion (t 2 in FIG. 10)
Is determined by the apex angle of the apex or the size of the convex portion and the interval between the apex and the apex, but the thickness for maintaining a large number of linear apexes in a parallel positional relationship with each other at minute intervals. (T 1 in FIG. 10) is necessary, and this t 1 is preferably thin in order to reduce the light transmittance and the thickness of the backlight, but for the reason of manufacturing the sheet and the strength, Total thickness of sheet (Fig. 10)
Medium T) is 10 to 3000 μm, preferably 50 to 100
0 μm is good. Moreover, it is more effective that the apexes formed on the same surface have the same shape.
【００３２】本発明で用いるシ−トを成形する方法は特
に限定されるものではなく、例えば熱プレスによる金型
成形加工、エンボス加工、鋳型加工、ベ−スフィルム上
に紫外線硬化樹脂を用いる方法、化学処理等の方法で実
質的に同形の頂稜を微細な間隔で互いに平行な状態で多
数有するように成形可能な方法であれば良い。尚、製造
上の理由から頂稜には若干のだれが生じるが、本発明の
効果が認められる範囲であれば良い。The method of molding the sheet used in the present invention is not particularly limited. For example, a method of molding by hot pressing, embossing, molding, or a method of using an ultraviolet curable resin on a base film. Any method can be used as long as it can be formed by a method such as chemical treatment so as to have a large number of substantially the same ridges in parallel with each other at fine intervals. It should be noted that although a slight sag occurs at the apex for manufacturing reasons, it may be within the range in which the effect of the present invention can be recognized.
【００３３】前記シ−トと導光板とは光学的に密着しな
いこと（例えば空気層を介していること）が好ましいの
で、前記シ−トの導光板と相対する面を若干粗面化した
り、スペ−サ−的要素を配して光学的密着を軽減するこ
とが好ましい。Since it is preferable that the sheet and the light guide plate do not come into optical contact with each other (for example, via an air layer), the surface of the sheet facing the light guide plate may be slightly roughened, It is preferable to provide a spacer element to reduce optical adhesion.
【００３４】液晶ディスプレイは、その表示面に降ろし
た法線方向近傍から視認する角度が大きくなる程コント
ラストが低くなるため、実用上、前記法線方向近傍での
輝度が重視される。更に、ビュ−ファインダ−に至って
はその表示面に降ろした法線方向からしか見ないため、
実用上、前記法線方向近傍での輝度が重視される。In a liquid crystal display, the contrast becomes lower as the viewing angle from the vicinity of the normal direction lowered on the display surface becomes larger. Therefore, practically, the brightness in the vicinity of the normal direction is important. Furthermore, since the viewfinder can be seen only from the direction normal to the display surface,
Practically, importance is attached to the brightness in the vicinity of the normal direction.
【００３５】本発明で、前記したように、出光面が微細
な間隔で互いに平行な多数の直線状プリズムを有するシ
−トを、前記バックライトの出光面に配すると、光の指
向性が現れる。即ち、実質的に出光面に降ろした法線方
向でその面より出光した光の輝度を測定した場合、前記
シ−トを配さない場合に比較して、輝度が増加されるこ
と、前記出光面に降ろした法線に対してある角度、例え
ば４０度の方向から同様に測定した輝度が、実質的に法
線方向で測定した時の輝度よりその減少割合が大となる
（例えば、法線方向で測定した時の輝度のほぼ５０％ま
で減少する）こと等から、前記した光の指向性が現れて
いることが判る。In the present invention, as described above, when a sheet having a large number of linear prisms whose light emitting surfaces are parallel to each other at fine intervals is arranged on the light emitting surface of the backlight, the directivity of light appears. . That is, when the brightness of the light emitted from the surface is measured substantially in the normal direction dropped to the light emitting surface, the brightness is increased as compared with the case where the sheet is not arranged, The luminance measured in the same manner from a direction at a certain angle, for example, 40 degrees with respect to the normal drawn to the surface, has a larger reduction rate than the luminance measured substantially in the normal direction (for example, the normal). It can be seen that the directivity of the above-mentioned light appears because it decreases to almost 50% of the luminance when measured in the direction.
【００３６】本発明の特徴は前記した頂稜がほぼ平行な
形状を持つ透光性材料からなるシ−トの頂稜が、前記し
た導光板上に仮想される直線と交差する状態に、１枚以
上配置することが特徴であるが、前記交差状態を更に詳
述すると、図１２に示したように、シ−トの頂稜（図中
８）と、導光板上に仮想される直線（図中７）とが互い
に交差する状態に配置することである。The feature of the present invention is that the top edge of the sheet made of a light-transmissive material having the substantially parallel top edges intersects with the above-mentioned straight line imaginary on the light guide plate. Although it is characterized by arranging more than one sheet, the crossing state will be described in more detail. As shown in FIG. 12, the top edge of the sheet (8 in the figure) and a straight line (imaginary line on the light guide plate ( In the figure, 7) and 7 are arranged so as to intersect with each other.
【００３７】前記したように前記シ−トの頂稜と前記互
いに交差する導光板上に仮想される直線とが互いに交差
する状態に配置することによって、光拡散性エレメント
の形状に対する隠蔽力が増大する。すなわち、ドット状
又はストライプ状などの光拡散性エレメントの形状が前
記したシ−トによって、導光板上の光拡散性エレメント
が形成されていない部分にも空間的には光拡散性エレメ
ントが形成されているかのように見えるのである。この
ような作用は、前記シ−トの頂稜と前記した導光板上に
仮想される直線とが互いに交差する状態に配置されるこ
とによって、前記したシ−トの光学的な作用により得ら
れるものである。As described above, by disposing the apex edge of the sheet and the virtual line on the light guide plate intersecting with each other so as to intersect with each other, the hiding power for the shape of the light diffusing element is increased. To do. That is, due to the above-described sheet shape of the light diffusing element such as the dot shape or the stripe shape, the light diffusing element is spatially formed even in a portion where the light diffusing element is not formed on the light guide plate. It looks as if they are. Such an action is obtained by the optical action of the sheet by disposing the apex edge of the sheet and the straight line imaginary on the light guide plate so as to intersect with each other. It is a thing.
【００３８】また、前記したシ−トを２枚以上積層する
と、輝度は前記したシ−トが１枚の時と比較して更に増
加されるが、ドット状又はストライプ状の光拡散性エレ
メントの形状に対する隠蔽力をより増加されるために、
シ−トの頂稜どうしが、互いに交差する状態であること
が好ましい。When two or more sheets are laminated, the brightness is further increased as compared with the case of one sheet, but the dot-shaped or striped light-diffusing element is used. In order to increase the hiding power for the shape,
It is preferable that the top edges of the sheets intersect each other.
【００３９】前記したシ−トの頂稜どうし交差の状態を
詳述すると、実質的に７５〜１１５度で交差する状態で
あることが好ましい。７５〜１１５度をはづれても光拡
散性エレメントであるドット状又はストライプ状の光拡
散性エレメントの形状に対する隠蔽力は存在するが、よ
り大きな隠蔽力が得られるのは７５〜１１５度、特に好
ましくは９０度付近である。また、この条件では同時に
輝度も向上する。The state where the apex edges of the sheet intersect each other will be described in detail. It is preferable that the apex ridges intersect substantially at an angle of 75 to 115 degrees. Although there is a hiding power for the shape of the dot-shaped or striped light-diffusing element which is the light-diffusing element even if it deviates from 75 to 115 degrees, it is particularly preferable that a larger hiding power can be obtained at 75 to 115 degrees. Is around 90 degrees. Also, under this condition, the brightness is simultaneously improved.
【００４０】本発明の主要部は、このような構成からな
り、パネル、特に液晶パネルのバックライトとして使用
される。本発明では、更に以下に示すような構成とする
ことが好ましい。The main part of the present invention has such a constitution and is used as a backlight of a panel, particularly a liquid crystal panel. In the present invention, it is preferable to have the following configuration.
【００４１】１）本発明の導光板に施す光拡散性エレメ
ントは、例えばドット状又はストライプ状に形成するも
のであるが、このドット状の場合の形状は特に制限され
るものでなく、円形、角形、交差線で形成されたいづれ
でもよい。これらは導光板上に仮想される一定の間隔を
持った直線の交点（グリッド）上に施されるが、交点の
間隔は０．０１〜５mm更に好ましくは０．０３〜２mmの
間で導光板の厚さに応じて適宜選択される。1) The light diffusing element applied to the light guide plate of the present invention is formed in, for example, a dot shape or a stripe shape, but the shape in the case of this dot shape is not particularly limited, and may be circular, The shape may be a polygon or a cross line. These are provided on intersections (grids) of straight lines that are virtually spaced on the light guide plate, and the distance between the intersections is 0.01 to 5 mm, more preferably 0.03 to 2 mm. Is appropriately selected according to the thickness.
【００４２】更に、前記光拡散物質を塗布する場合の被
覆状態は、導光板面上で線状光源部近傍で被覆率が１％
〜５０％、光源から最遠部で２０％〜１００％であるこ
とが好ましく、光源からの距離が大となるにつれて、光
源から線状光源を近接させた一側面端部の被覆点から始
めて被覆率が順次大となるように被覆することが好まし
い。ここで言う被覆率とは、導光板面の単位面積当たり
に施した光拡散性エレメントの被覆面積の割合を言う。Further, in the coating state when the light diffusing substance is applied, the coating rate is 1% near the linear light source portion on the light guide plate surface.
˜50%, preferably 20% to 100% at the farthest part from the light source, and as the distance from the light source increases, the covering starts from the covering point at one side end where the linear light source is brought close to the light source. It is preferable that the coating be performed so that the ratio becomes higher in sequence. The term "coverage" as used herein means the ratio of the coverage of the light diffusing element per unit area of the light guide plate surface.
【００４３】更に、本発明では、発光面上で、線状光源
の軸と平行となる状態のグリッド上に被覆される光拡散
物質の被覆率が、その平行線上の中央（即ち、線状光源
の長手方向の中央）から線状光源に垂直に立てた導光板
面上の線から両端に向かう方向の光拡散物質までの距離
に対して、順次大となるように被覆することが好まし
い。本発明は、出光面の上面に液晶パネルなどの光表示
パネルを設置して使用される。Further, in the present invention, the coverage of the light diffusing substance coated on the grid in the state of being parallel to the axis of the linear light source on the light emitting surface is such that the center of the parallel line (that is, the linear light source). It is preferable that the distance from the line on the surface of the light guide plate standing perpendicular to the linear light source to the light diffusing substance in the direction toward both ends is gradually increased from the center in the longitudinal direction). The present invention is used by installing an optical display panel such as a liquid crystal panel on the upper surface of the light emitting surface.
【００４４】[0044]
【発明の効果】本発明は、消費電力−輝度変換効率が高
く、導光板に形成された光拡散性エレメントが十分隠蔽
された状態であり、例えば１mm程度の超薄型の導光板を
用いた場合でも十分隠蔽効果がえられ薄型なバックライ
トとして得られる。According to the present invention, the power consumption-luminance conversion efficiency is high and the light diffusing element formed on the light guide plate is sufficiently concealed. For example, an ultrathin light guide plate of about 1 mm is used. Even in the case, the hiding effect can be sufficiently obtained and the backlight can be obtained as a thin type.
【００４５】[0045]
【実施例】次に比較例及び実施例で本発明を更に詳述す
る。図３に示すような厚さ４mmの長方形導光板（旭化成
製、AC-999、材質はＰＭＭＡ、２１０mm×１５５mm）の
長手の両端部に、直径３．８mmの太さの冷陰極蛍光管
（ハリソン電機株式会社製）を配置し、導光板に接する
部分に４mmのスリットを持つＡｇフィルムを反射面が光
源と対向するように楕円形に配置し、スリットから出光
した光が導光板の端部から導光板に入光するように配置
した。一方、導光板面上に形成する光拡散性エレメント
は、チタンホワイトを含む塗料を、図５に示すような導
光板上に仮想される１mmの間隔を持った直交線の交点
（グリッド）上に円形のドットパタ−ンで印刷したもの
であり下記の条件で形成した。光拡散性エレメントの被
覆率が、最小の地点で２６％、最大の地点で９０％、そ
の中間ではこれらの比率を順次増加した値となるように
印刷した。また、線状光源の軸と平行となる状態のグリ
ッド上に被覆される光拡散物質の被覆率が、その平行線
上の中央、即ち、線状光源の長手方向の中央から線状光
源に垂直に立てた導光板面上の線から両端に向かう方向
の光拡散物質までの距離に対して、順次大となるよう
に、最小の地点で２６％、最大の地点で４０％、その中
間ではこれらの比率を順次増加した値となるように印刷
した。EXAMPLES Next, the present invention will be described in more detail with reference to Comparative Examples and Examples. As shown in Fig. 3, a rectangular light guide plate with a thickness of 4 mm (AC-999, manufactured by Asahi Kasei, material is PMMA, 210 mm x 155 mm) is provided on both longitudinal ends of a cold cathode fluorescent tube (Harrison Harrison) with a diameter of 3.8 mm. (Made by Denki Co., Ltd.), and an Ag film having a slit of 4 mm in a portion in contact with the light guide plate is arranged in an elliptical shape so that the reflection surface faces the light source, and the light emitted from the slit is emitted from the end of the light guide plate. The light guide plate is arranged so as to enter the light. On the other hand, the light diffusing element formed on the surface of the light guide plate is formed by coating the paint containing titanium white on the intersections (grids) of the orthogonal lines with a virtual interval of 1 mm on the light guide plate as shown in FIG. It was printed with a circular dot pattern and was formed under the following conditions. Printing was performed so that the coverage of the light diffusing element was 26% at the minimum point, 90% at the maximum point, and in the middle thereof, these ratios were successively increased. Further, the coverage of the light diffusing substance coated on the grid in a state parallel to the axis of the linear light source is the center on the parallel line, that is, from the longitudinal center of the linear light source to the vertical direction to the linear light source. With respect to the distance from the line on the standing light guide plate surface to the light diffusing substance in the direction toward both ends, 26% at the minimum point, 40% at the maximum point, and these in the middle between these, so that the distance gradually increases. Printing was performed such that the ratio was increased in order.
【００４６】導光板の光拡エレメントを印刷した面を厚
さ０．１２５mmの光拡散反射シ−ト（ＩＣＩ製メリネッ
クス 329）で覆った。さらに、導光板の出光面側に厚さ
０．１mmの両面が粗面の光拡散シ−ト（辻本電機製作所
D-204）を１枚配置した。The surface of the light guide plate on which the light-spreading element was printed was covered with a 0.125 mm-thick light diffusion reflection sheet (Melinex 329 manufactured by ICI). Furthermore, a light diffusion sheet with a thickness of 0.1 mm on both sides of the light guide plate, which has a rough surface (Tsujimoto Electric Works)
One sheet of D-204) was placed.
【００４７】冷陰極管に、インバ−タ（ＴＤＫ製CXAM-1
0L）より３０KHz の交番電圧をかけて一定電流（１本の
冷陰極管に対して５mA、２本では合計１０mA）で駆動さ
せたときの面輝度を、輝度計（トプコンBM-8）により視
野角２度で出光面に降ろした法線方向に対して測定した
ところ１３００cd/m2 であった。このとき、ドットは光
拡散シ−トを通しては透けて見えなかった。また、光の
指向性は殆どなかった（比較例１）。An inverter (TDK CXAM-1
0L) and a constant current (5mA for one cold-cathode tube and a total of 10mA for one cold cathode tube) applied with an alternating voltage of 30KHz, and the surface brightness when driven by a luminance meter (Topcon BM-8). It was 1300 cd / m 2 when measured with respect to the direction normal to the light exit surface at an angle of 2 degrees. At this time, the dots could not be seen through the light diffusion sheet. Moreover, there was almost no directivity of light (Comparative Example 1).
【００４８】前記光拡散シ−トに代えてポリカ−ボネイ
トからなる、互いに平行な直線状凸部を多数有する、直
線状凸部の隣り合った頂稜と頂稜との間隔が１４０μm
の間隔になるように加工した厚さ２５０μm の透光性シ
−トをその直線状頂稜が前記した導光板上に仮想される
実質的に平行な線と平行な状態に、頂稜面側が外側にな
るように出光面側に１枚配置した以外は比較例１と同一
の装置、条件、で操作し、測定した輝度は１８００cd/m
2 であった。このとき、ドットは透光性シ−トを通して
透けて見えた。そのドットが見えた状態は、互いに平行
な直線状頂稜とは直交する方向に隣接したドットが連な
って、ライン状（更に詳述すると串団子状）となった状
態だった。また、出光面に降ろした法線方向に対して光
の指向性が観察された（比較例２）。Instead of the light diffusing sheet, there are a number of parallel linear protrusions made of polycarbonate, and the distance between adjacent apexes of the linear protrusions is 140 μm.
The translucent sheet having a thickness of 250 μm processed so as to have an interval of is placed in a state in which the linear apex is parallel to the virtually parallel line imaginary on the light guide plate, and the apex side is The brightness was 1800 cd / m as measured by operating under the same apparatus and conditions as in Comparative Example 1 except that one sheet was arranged on the light emitting surface side so as to be outside.
Was 2 . At this time, the dots were seen through the translucent sheet. The state in which the dots were visible was a state in which dots that were adjacent to each other in a direction orthogonal to the straight apexes that were parallel to each other formed a line shape (more specifically, a skewer dumpling shape). In addition, the directivity of light was observed with respect to the direction normal to the light exit surface (Comparative Example 2).
【００４９】前記凸部を多数有するシ−トをその直線状
頂稜が前記した導光板上に仮想される実質的に平行な直
線と交差する状態に配置した以外は比較例２と同一の装
置、条件、で操作し、測定した輝度は１８００cd/m2 で
あった。このとき、ドットは透光性シ−トを通して透け
て見えなかった。そして、シートを回転させてドット形
状に対する隠蔽力を調べた所、２０〜７０度で交差する
状態であると隠蔽力が更に増大した。特に４５度付近で
隠蔽力が最大となった（目視により観察した。以下同
じ）又、出光面に降ろした法線方向に対して光の指向性
が観察された（実施例１）。The same apparatus as in Comparative Example 2 except that the sheet having a large number of convex portions is arranged such that the linear apex thereof intersects with the substantially parallel straight line imaginary on the light guide plate. The luminance measured under the above conditions was 1800 cd / m 2 . At this time, the dots could not be seen through the translucent sheet. Then, when the sheet was rotated and the hiding power for the dot shape was examined, the hiding power was further increased when the sheet intersected at 20 to 70 degrees. In particular, the hiding power was maximized near 45 degrees (observed visually. The same applies hereinafter), and the directivity of light was observed with respect to the normal direction dropped on the light exit surface (Example 1).
【００５０】前記凸部を有する透光性シ−トを２枚用
い、その直線状頂稜が互いに平行になるように配置した
以外は比較例２と同一の装置、条件、で操作し、測定し
た輝度は１８５０cd/m2 であった。このとき、ドットは
透光性シ−トを通して透けて見えた。そのドットが見え
た状態は、互いに平行な直線状頂稜とは直交する方向に
隣接したドットが連なって、ライン状（更に詳述すると
串団子状）となった状態だった。また２枚の前記シ−ト
同士が光学的に干渉してモアレ現象が観察された。また
出光面に降した法線方向に対して光の指向性が観察され
た（比較例３）。Measurement was carried out by operating with the same apparatus and conditions as in Comparative Example 2 except that two light-transmitting sheets having the above-mentioned convex portions were used and were arranged so that their linear ridges were parallel to each other. The luminance was 1850 cd / m 2 . At this time, the dots were seen through the translucent sheet. The state in which the dots were visible was a state in which dots that were adjacent to each other in a direction orthogonal to the straight apexes that were parallel to each other formed a line shape (more specifically, a skewer dumpling shape). Further, the moire phenomenon was observed due to the optical interference between the two sheets. In addition, the directivity of light was observed with respect to the direction normal to the light exit surface (Comparative Example 3).
【００５１】前記凸部を有する透光性シ−トを２枚用
い、その直線状頂稜が互いに交差するように配置した以
外は実施例１と同一の装置、条件、で操作し、測定した
輝度は１９００cd/m2 であった。このとき、ドットは透
光性シ−トを通して透けて見えなかったがその隠蔽力を
調べた所、２枚のシ−トの直線状頂稜が互いに７５〜１
１５度で交差する状態であると隠蔽力が更に増大した。
特に９０度付近で隠蔽力が最大となった。また輝度も２
枚のシ−トの直線状頂稜が互いに７５〜１１５度で交差
する状態であると増大し、特に９０度付近で輝度が最大
（２２００cd/m2）となった。また、出光面に降ろした
法線方向に対して光の指向性が観察された（実施例
２）。Measurement was carried out by operating with the same apparatus and conditions as in Example 1 except that two light-transmitting sheets having the above-mentioned convex portions were used and were arranged so that their linear apexes intersect each other. The brightness was 1900 cd / m 2 . At this time, the dots could not be seen through the translucent sheet, but when the hiding power was examined, the linear crests of the two sheets were 75 to 1 each other.
The hiding power was further increased when crossing at 15 degrees.
Especially, the hiding power became maximum around 90 degrees. Also the brightness is 2
It increased when the straight ridges of the sheets intersected with each other at 75 to 115 degrees, and the brightness became maximum (2200 cd / m 2 ) especially near 90 degrees. In addition, the directivity of light was observed with respect to the direction of the normal line dropped on the light exit surface (Example 2).
【００５２】前記凸部を有する透光性シ−トに代えてポ
リカ−ボネイトからなる頂角が９０度の互いに平行な直
線状プリズムを多数有する、直線状プリズムの隣り合っ
た頂稜と頂稜との間隔が３５０μm の間隔になるように
加工した厚さ３６０μm のシ−トを用いた以外は比較例
２と同一の装置、条件、で操作し、測定した輝度は２０
００cd/m2 であった。このとき、ドットは透光性シ−ト
を通して透けて見えた。そのドットが見えた状態は、互
いに平行な直線状頂稜とは直交する方向に隣接したドッ
トが楕円状となった状態だった（比較例２のように連っ
てはいなかった）。また出光面に降した法線方向に対し
て光の指向性が観察された（比較例４）。Adjacent ridges and ridges of linear prisms having a large number of linear prisms made of polycarbonate and parallel to each other and having an apex angle of 90 degrees instead of the translucent sheet having the convex portions. And the same conditions and conditions as in Comparative Example 2 were used, except that a sheet having a thickness of 360 μm processed so as to have a distance of 350 μm was used, and the measured luminance was 20.
It was 00 cd / m 2 . At this time, the dots were seen through the translucent sheet. The state in which the dots were visible was a state in which dots adjacent to each other in the direction orthogonal to the linear vertexes parallel to each other became elliptical (not continuous as in Comparative Example 2). In addition, the directivity of light was observed with respect to the direction normal to the light exit surface (Comparative Example 4).
【００５３】プリズムを持つ透光性シートを用い実施例
１と同様にして測定した輝度は２０００cd/m2 であっ
た。このとき、ドットは透光性シ−トを通して透けて見
えなかった。そして、透光性シートを回転させてドット
形状に対する隠蔽力を調べた所、２０〜７０度で交差す
る状態であると隠蔽力が更に増大した。特に４５度付近
で隠蔽力が最大となった。また、出光面に降ろした法線
方向に対して光の指向性が観察された（実施例３）。The brightness measured by the same method as in Example 1 using a translucent sheet having a prism was 2000 cd / m 2 . At this time, the dots could not be seen through the translucent sheet. When the hiding power for the dot shape was examined by rotating the translucent sheet, the hiding power was further increased in the state of intersecting at 20 to 70 degrees. Especially, the hiding power became maximum around 45 degrees. In addition, the directivity of light was observed with respect to the normal direction dropped on the light exit surface (Example 3).
【００５４】更にこの透光性シートを２枚用い実施例２
と同様にしてドットに対する隠蔽力を調べた結果、２枚
の前記シ−トの直線状頂稜が互いに７５〜１１５度で交
差する状態であると隠蔽力が更に増大した。特に９０度
付近で隠蔽力が最大となった。又輝度も２枚の前記シ−
トの直線状頂稜が互いに７５〜１１５度で交差する状態
であると増大し、特に９０度付近で輝度が最大（２１０
０cd/m2 ）となった。又、出光面に降ろした法線方向に
対して光の指向性が観察された（実施例４）。Further, two sheets of this translucent sheet were used in Example 2.
As a result of examining the hiding power with respect to the dots in the same manner as above, the hiding power was further increased when the straight apexes of the two sheets intersect each other at 75 to 115 degrees. Especially, the hiding power became maximum around 90 degrees. In addition, the brightness of the two sheets
It increases when the apical straight ridges intersect with each other at an angle of 75 to 115 degrees, and the maximum brightness (210 degrees) is obtained especially near 90 degrees.
It became 0 cd / m 2 ). In addition, the directivity of light was observed with respect to the direction normal to the light exit surface (Example 4).
【００５５】次にチタンホワイトを含む塗料を、図６に
示すような導光板上に仮想される１mmの間隔を持った互
いに最小角３０度で交差する直線の交点（グリッド）上
に円形のドットパタ−ンで印刷した以外は実施例１と同
一の装置、条件、で操作しシートを回転させてドット形
状に対する隠蔽力を調べた所、透光性シートの直線状頂
稜と仮想線とのなす角度が１３〜４７度で交差する状態
であると隠蔽力が更に増大した。特に３０度付近で隠蔽
力が最大となった。また、出光面に降ろした法線方向に
対して光の指向性が観察された（実施例５）。Next, a coating containing titanium white was applied on the light guide plate as shown in FIG. 6 with circular dot patterns on the intersections (grids) of straight lines intersecting each other at a minimum angle of 30 degrees with a virtual distance of 1 mm. -The sheet was rotated under the same conditions and conditions as in Example 1 except that printing was performed using a sheet, and the hiding power for the dot shape was examined. The hiding power was further increased when the angle crossed at 13 to 47 degrees. Especially, the hiding power became maximum around 30 degrees. In addition, the directivity of light was observed with respect to the direction normal to the light exit surface (Example 5).
【００５６】次にチタンホワイトを含む塗料を、図７に
示すような導光板上に仮想される１mmの間隔を持った互
いに平行なで線上にストライプ形のパタ−ンで印刷した
以外は実施例１と同一の装置、条件、で操作し透光性シ
ートを回転させてドット形状に対する隠蔽力を調べた
所、シートの直線状頂稜と仮想線とのなす角度が２０〜
７０度で交差する状態であると隠蔽力が更に増大した。
特に４５度付近で隠蔽力が最大となった。また、出光面
に降した法線方向に対して光の指向性が観察された（実
施例６）。Next, an example was applied except that the paint containing titanium white was printed on the light guide plate as shown in FIG. 7 in a stripe pattern on parallel lines with a virtual interval of 1 mm. When the concealing power for the dot shape was examined by rotating the translucent sheet by operating under the same apparatus and conditions as in No. 1, the angle between the linear apex of the sheet and the virtual line was 20 to
The hiding power was further increased when crossing at 70 degrees.
Especially, the hiding power became maximum around 45 degrees. In addition, the directivity of light was observed with respect to the direction normal to the light exit surface (Example 6).
【００５７】１mm厚さで、図８に示すような中心どうし
を結ぶ仮想線が正方形を形成するようにドットパターン
を形成したの導光板を用いた以外は実施例１と同一の装
置、条件で操作したところ、ドットの隠蔽力に関して実
施例１と同様の結果を得た（実施例７）。The same apparatus and conditions as in Example 1 were used except that a light guide plate having a thickness of 1 mm and having a dot pattern formed so that an imaginary line connecting centers as shown in FIG. 8 forms a square. When operated, the same results as in Example 1 were obtained with respect to the hiding power of the dots (Example 7).
【図１】従来の一実施態様のバックライトの斜視図FIG. 1 is a perspective view of a backlight according to a conventional embodiment.
【図２】従来の一実施態様のバックライトの断面図FIG. 2 is a sectional view of a conventional backlight according to an embodiment.
【図３】本発明の一実施態様のバックライトの斜視図FIG. 3 is a perspective view of a backlight according to an embodiment of the present invention.
【図４】本発明の一実施態様のバックライトの断面図FIG. 4 is a sectional view of a backlight according to an embodiment of the present invention.
【図５】本発明で用いる導光板の光拡散性エレメントに
対する仮想線を例示する図FIG. 5 is a diagram illustrating an imaginary line with respect to a light diffusing element of a light guide plate used in the present invention.
【図６】本発明で用いる導光板の光拡散性エレメントに
対する仮想線を例示する図FIG. 6 is a diagram illustrating an imaginary line for a light diffusing element of a light guide plate used in the present invention.
【図７】本発明で用いる導光板の光拡散性エレメントに
対する仮想線を例示する図FIG. 7 is a diagram illustrating an imaginary line for a light diffusing element of a light guide plate used in the present invention.
【図８】本発明で用いる導光板の光拡散性エレメントに
対する仮想線を例示する図FIG. 8 is a diagram illustrating an imaginary line for a light diffusing element of a light guide plate used in the present invention.
【図９】本発明で用いる導光板の光拡散性エレメントに
対する仮想線を例示する図FIG. 9 is a diagram illustrating an imaginary line for a light diffusing element of a light guide plate used in the present invention.
【図１０】本発明で用いる透光性シートの面の構造の一
例を示す図FIG. 10 is a diagram showing an example of the structure of the surface of the translucent sheet used in the present invention.
【図１１】本発明で用いる透光性シートの面の構造の他
の例を示す図FIG. 11 is a diagram showing another example of the structure of the surface of the translucent sheet used in the present invention.
【図１２】本発明での透光性シートと導光板の仮想線の
位置の例を示す図FIG. 12 is a diagram showing an example of positions of imaginary lines of a translucent sheet and a light guide plate in the present invention.
１：導光板 ２：光拡散シート ３：光反射板 ４：光源 ５：光源を覆う光反射板 ６：光拡散性エレメント ７：導光板上の仮想直線 ８：プリズム形状の頂綾 ９：頂角 １０：プリズム形状を持つ透光性シート １１：凸状部の頂綾 １２：凸状部の形状を持つ透光性シート 1: Light guide plate 2: Light diffusing sheet 3: Light reflecting plate 4: Light source 5: Light reflecting plate that covers the light source 6: Light diffusing element 7: Virtual straight line on the light guiding plate 8: Prismatic top 9: Vertical angle 10: Translucent sheet having a prism shape 11: Top and bottom of a convex portion 12: Translucent sheet having a convex portion shape
Claims (9)
に、ドット状又はストライプ状に光拡散性エレメントを
形成し、前記導光板の少なくとも一側面端部にこれに近
接した線状光源を有するパネル用バックライトに於い
て、導光板の出光面側に、微細な間隔で直線状頂稜をも
つプリズム又は同凸状部が、前記頂稜がほぼ平行となる
状態で同一面に多数有する透光性材料からなるシ−ト
を、前記直線状頂稜が、中心が最短距離で隣合うドット
状の光拡散性エレメントの中心どうしを結ぶ仮想直線、
又は前記ストライプ状の光拡散性エレメントの中心線ど
うしを最短距離で結ぶ仮想直線と交差する状態に１枚以
上配置したパネル用バックライト。1. A light-diffusing element formed in a dot shape or a stripe shape on one wide surface of a light guide plate made of a light-transmissive material, and a linear shape adjacent to at least one side surface end portion of the light guide plate. In a panel backlight having a light source, prisms or convex portions having linear apexes at fine intervals are formed on the same surface on the light emitting surface side of the light guide plate with the apexes being substantially parallel. A sheet composed of a large number of light-transmissive materials, the linear top edge is a virtual straight line connecting the centers of the dot-shaped light diffusing elements whose centers are adjacent to each other at the shortest distance,
Alternatively, one or more panel backlights arranged in a state of intersecting a virtual straight line connecting the center lines of the striped light diffusing elements with each other at the shortest distance.
又は楕円型の一部の形状又は波型である透光性材料から
なるシ−トを用いる請求項１記載のバックライト。2. A sheet made of a light-transmissive material, the cross section of which is perpendicular to the apex of the convex portion is partly circular or partly elliptical or corrugated. Backlight.
７０度で交差する状態に透光性材料からなるシ−トを配
置した請求項１又は２記載のバックライト。3. The straight ridge of the sheet and the imaginary straight line are 10 to 10.
The backlight according to claim 1 or 2, wherein a sheet made of a translucent material is arranged in a state of intersecting at 70 degrees.
するドット状の光拡散性エレメントを、一方の広い面に
形成した導光板である請求項１〜３いづれか記載のバッ
クライト。4. The backlight according to any one of claims 1 to 3, which is a light guide plate having a dot-shaped light diffusing element in which a virtual straight line connecting the centers forms a square on one wide surface.
７０度で交差する状態に透光性材料からなるシ−トを配
置した請求項４記載のバックライト。5. The straight ridge of the sheet and the imaginary straight line are 20 to 20.
The backlight according to claim 4, wherein a sheet made of a translucent material is arranged in a state of intersecting at 70 degrees.
成するドット状の光拡散性エレメントを、一方の広い面
に形成した導光板である請求項１〜３いづれか記載のバ
ックライト。6. The backlight according to claim 1, which is a light guide plate in which a dot-shaped light diffusing element in which an imaginary straight line connecting the centers forms an equilateral triangle is formed on one wide surface.
５０度で交差する状態に透光性材料からなるシ−トを配
置した請求項６記載のバックライト。7. The straight ridge of the sheet and the imaginary straight line are 10 to 10.
7. The backlight according to claim 6, wherein a sheet made of a translucent material is arranged in a state of intersecting at 50 degrees.
それらの直線状頂稜が、互いに実質的に７５〜１１５度
で交差する状態である請求項１〜７いづれか記載のバッ
クライト。8. A plurality of sheets made of a translucent material are used,
The backlight according to any one of claims 1 to 7, wherein the straight apexes intersect with each other at substantially 75 to 115 degrees.
隣り合った頂稜どうしの間隔が１０〜１０００μｍであ
るシ−トを用いた請求項１〜８いづれか記載のバックラ
イト。9. The backlight according to claim 1, wherein a sheet having a straight crest of a sheet made of a translucent material and having a distance between adjacent crests of 10 to 1000 μm is used. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6009730A JP2723030B2 (en) | 1993-02-01 | 1994-01-31 | Backlight |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5-14886 | 1993-02-01 | ||
| JP1488693 | 1993-02-01 | ||
| JP6009730A JP2723030B2 (en) | 1993-02-01 | 1994-01-31 | Backlight |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06281934A true JPH06281934A (en) | 1994-10-07 |
| JP2723030B2 JP2723030B2 (en) | 1998-03-09 |
Family
ID=26344503
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6009730A Expired - Fee Related JP2723030B2 (en) | 1993-02-01 | 1994-01-31 | Backlight |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2723030B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040024348A (en) * | 2002-09-14 | 2004-03-20 | 누비텍 주식회사 | Plastic optical fiber with multi-layer structure of clad and one side layer of clad, POF with various shape and function, the equipment and method manufacturing the above POFs, applied products |
| WO2006080710A1 (en) * | 2004-10-09 | 2006-08-03 | Cheil Industries Inc. | Light guide plate for liquid crystal display back light units and liquid crystal display back light unit using the same |
-
1994
- 1994-01-31 JP JP6009730A patent/JP2723030B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040024348A (en) * | 2002-09-14 | 2004-03-20 | 누비텍 주식회사 | Plastic optical fiber with multi-layer structure of clad and one side layer of clad, POF with various shape and function, the equipment and method manufacturing the above POFs, applied products |
| WO2006080710A1 (en) * | 2004-10-09 | 2006-08-03 | Cheil Industries Inc. | Light guide plate for liquid crystal display back light units and liquid crystal display back light unit using the same |
| JP2008516391A (en) * | 2004-10-09 | 2008-05-15 | チェイル インダストリーズ インコーポレイテッド | Light guide plate for liquid crystal display device backlight unit and liquid crystal display device backlight unit using the same |
| US7602551B2 (en) | 2004-10-09 | 2009-10-13 | Cheil Industries, Inc. | Light guide plate for liquid crystal display back light units and liquid crystal display back light unit using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2723030B2 (en) | 1998-03-09 |
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