JPH08111106A - Backlight - Google Patents
BacklightInfo
- Publication number
- JPH08111106A JPH08111106A JP7140544A JP14054495A JPH08111106A JP H08111106 A JPH08111106 A JP H08111106A JP 7140544 A JP7140544 A JP 7140544A JP 14054495 A JP14054495 A JP 14054495A JP H08111106 A JPH08111106 A JP H08111106A
- Authority
- JP
- Japan
- Prior art keywords
- light
- sheet
- backlight
- guide plate
- plate
- 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.)
- Pending
Links
Landscapes
- Liquid Crystal (AREA)
- Planar Illumination Modules (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Optical Elements Other Than Lenses (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１灯型エッジライト方
式、図３に示すように透光性の導光板の対向する二端部
に、蛍光管のような線状光源を併設する２灯型エッジラ
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又は図４はに示すように、導光板の一方の面
にこの導光板材料よりも屈折率が大きい光拡散物質を部
分的に被覆し、その面のほぼ全面を光拡散反射板で覆う
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, a one-lamp type edge light system 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. 1, and as shown in FIG. A two-lamp type edge light system in which a linear light source such as a fluorescent tube is provided at two opposite ends of a light guide plate is often used. In the case of this edge light method, as shown in FIG. 2 or 4, one surface of the light guide plate is partially covered with a light diffusing substance having a refractive index larger than that of the material of the light guide plate, and almost the entire surface thereof is covered. Many are arranged so as to be covered with a light diffusion reflector.
【０００３】特に近時、バックライトがバッテリー駆動
されるようになり消費電力−輝度変換効率のより一層の
向上が望まれており、線状光源を覆う光反射器に反射率
の高い反射板を配したり、導光板の光拡散物質を部分的
に被覆した面に反射率の高い反射板を配したりすること
が提案されている。Particularly, in recent years, since the backlight is driven by a battery, further improvement of power consumption-luminance conversion efficiency is desired, and a light reflector for covering the linear light source is provided with a reflector having a high reflectance. It has been proposed to dispose the light guide plate or to dispose a reflection plate having a high reflectance on the surface of the light guide plate that is partially covered with the light diffusing substance.
【０００４】しかし、前記したいづれの方法において
も、消費電力−輝度変換効率は向上するものの、未だ充
分でなく、更により一層の向上が望まれている。However, although the power consumption-luminance conversion efficiency is improved by any of the above-mentioned methods, it is still not sufficient, and further improvement is desired.
【０００５】[0005]
【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、かつ高輝度が得られるバッ
クライトを提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a backlight which has high power consumption-luminance conversion efficiency and high luminance.
【０００６】[0006]
【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、光拡散物質を部分的に
被覆した透光性材料の出光面側に、直線状頂稜を多数有
する透光性プリズムシ−トを配したが、光の指向性がよ
り強くなり、実質的に出光面に降ろした法線方向近傍に
対しては前記した消費電力−輝度変換効率の高いバック
ライトとなることを見出した。As a result of various studies on the above points, the inventors of the present invention have found that a linear top edge is formed on the light emitting surface side of a translucent material partially covered with a light diffusing substance. Although a light transmissive prism sheet having a large number of is arranged, the directivity of light becomes stronger, and the power consumption-luminance conversion efficiency is high for the vicinity of the normal direction substantially dropped on the light emitting surface. I found it to be a light.
【０００７】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、拡散反射率の大きい顔料を含んでな
る光拡散物質を部分的に被覆し、その面を鏡面ないし光
反射板で覆い、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、同一面に微細な間隔で直線状頂稜を持つプリズ
ムが、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−トであって、前記シートは透光性フィル
ム上に前記フィルムとは異質の透光性材質で直線状頂稜
を持つプリズムを形成したものであり、このシートを導
光板の出光面側に光拡散シートを介して頂稜面が外側に
なるように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, one wide surface of a light guide plate made of a translucent material is partially coated with a light diffusing substance containing a pigment having a large diffuse reflectance, and the surface is mirror-finished or light-reflected. In a backlight for a panel which is covered with a plate and has a linear light source close to at least one side surface end portion of the light guide plate, a prism having linear vertexes on the same surface at fine intervals A sheet comprising a large number of translucent materials arranged in a substantially parallel state, wherein the sheet is a translucent film and a prism having a straight apex made of a translucent material different from the film is formed on the translucent film. The present invention relates to a backlight for a panel in which one or more sheets are arranged on the light emitting surface side of a light guide plate with a light diffusing sheet so that the top ridge surface is on the outside.
【０００８】次に本発明を図面に基づいて詳述する。図
５は、導光板の一端部に光源を持つエッジライト方式の
一実施態様の斜視図であり、図６はその断面図である。
同様に図７は、導光板の二端部に光源を持つエッジライ
ト方式の一実施態様の斜視図であり、図８はその断面図
である。Next, the present invention will be described in detail with reference to the drawings. FIG. 5 is a perspective view of an embodiment of an edge light system having a light source at one end of a light guide plate, and FIG. 6 is a sectional view thereof.
Similarly, FIG. 7 is a perspective view of an embodiment of an edge light system having light sources at two ends of the light guide plate, and FIG. 8 is a sectional view thereof.
【０００９】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ある。導光板
に施す光拡散物質（図中６）は、導光板の材質に比較し
て高屈折率を持ち、かつ拡散反射率が大きい顔料、例え
ばチタンホワイトを含んだ塗料、印刷インキ等である。
これらをスクリ−ン印刷等の方法で導光板面上にドット
状に印刷する。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. The light diffusing substance (6 in the figure) applied to the light guide plate is a pigment having a high refractive index and a large diffuse reflectance as compared with the material of the light guide plate, for example, paint containing titanium white, printing ink, or the like.
These are printed in dots on the surface of the light guide plate by a method such as screen printing.
【００１０】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、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 reflector 5 having a gap (slit) for allowing light to enter the end portion of the light guide plate is covered with a gap of a certain width from the light source surface of the linear light source, and at least the light guide plate is covered. It is installed close to the one end face so 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. However, a fluorescent tube is preferable, and from the viewpoint of power saving, the length of the uniform light emitting portion excluding the electrode portion 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.
【００１１】鏡面ないし光反射板、例えば光拡散反射板
（図中３）は光拡散物質を被覆した導光板の面のほぼ全
面を覆うように配置するが、導光板の線状光源を近接さ
せていない残りの端面部のほぼ全面を覆うように配置す
ると光の利用効率及び均一な面状発光を得る点で更に良
い。The mirror surface or the light reflecting plate, for example, the light diffusing reflecting plate (3 in the figure) is arranged so as to cover almost the entire surface of the light guiding plate coated with the light diffusing substance. It is more preferable to dispose so as to cover almost the entire remaining end face portion, in terms of light utilization efficiency and uniform planar light emission.
【００１２】７は透光性材料からなるシ−ト（以下単に
シートと称する）で、同一面に微細な間隔で互いに平行
な直線状頂稜を多数有するもので、頂稜面が外側（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
性をより強くさせるものである。前記直線状頂稜部が線
状光源の中心軸と平行になるように配置しても良いし、
直角になるように配置しても良い。Reference numeral 7 is a sheet made of a translucent material (hereinafter simply referred to as a sheet), which has a large number of straight apexes parallel to each other on the same surface at fine intervals. By arranging so that it is on the side opposite to the surface facing the light plate), the directivity of the light emitted from the light emitting surface of the backlight is changed, and the directivity in the vicinity of the normal direction dropped on the light emitting surface is made stronger. It is a thing. It may be arranged such that the linear apex portion is parallel to the central axis of the linear light source,
You may arrange so that it may become a right angle.
【００１３】本発明ではこのシ−トを１枚又は複数枚用
いるが、例えば２枚用いる場合には、互いの直線状頂稜
部が直交するように２枚とも頂稜面が外側になるように
重ね合わせれば、本発明の効果、即ち消費電力−輝度変
換効率は更に増加する。尚、導光板面上に印刷されたド
ット状の光拡散物質（図中６）のドット状のパタ−ンの
識別が不可能となるように、必要に応じて、前記シ−ト
と前記導光板との間に光拡散板（図中２）を配置しても
良い。ここで用いる光拡散板は市販の光拡散シート（フ
ィルム）等が用いられる。In the present invention, one sheet or a plurality of sheets are used. When, for example, two sheets are used, both apical ridges are located outside so that their linear apexes are orthogonal to each other. , The effect of the present invention, that is, the power consumption-luminance conversion efficiency is further increased. If necessary, the sheet and the guide should be arranged so that the dot-shaped pattern of the dot-shaped light diffusing substance (6 in the figure) printed on the light guide plate surface cannot be identified. A light diffusion plate (2 in the figure) may be arranged between the light plate and the light plate. As the light diffusion plate used here, a commercially available light diffusion sheet (film) or the like is used.
【００１４】本発明は、前記したように、バックライト
の出光面側に、ある条件を満足する形状を持つ透光性材
料からなるシ−トを配置することが特徴である。As described above, the present invention is characterized in that a sheet made of a translucent material having a shape satisfying a certain condition is arranged on the light emitting surface side of the backlight.
【００１５】本発明における前記条件を更に詳述する
と、前記したシ−ト（図中７）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、ポリエチレンテレフタレート（ＰＥ
Ｔ）などのポリエステル、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 above-mentioned conditions in the present invention will be described in more detail. The above-mentioned sheet (7 in the figure) is not particularly limited as long as it is made of a translucent material. For example, methacrylic acid ester, polycarbonate, poly Vinyl chloride, polystyrene, polyamide, polyethylene terephthalate (PE
T) and other polyesters, polyethylene, polypropylene, fiber-based resin glass, and the like.
【００１６】本発明で用いるシ−トの、出光面側に形成
する互いに平行な直線状頂稜を有するプリズムの形状は
図９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
する状態である。シー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。As shown in FIG. 9, the shape of a prism having straight parallel ridges formed on the light output surface side of the sheet used in the present invention is parallel to each other, as shown in FIG. In this state, 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. The apex angles of these apexes formed on the sheet have portions of substantially the same shape. This means that the apex angles have substantially the same angle when cut under the same conditions centering on the apex. Means that.
【００１７】本発明に於いては、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。前記頂角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−ボネート、
屈折率ｎ＝１．５９）を用いた場合は、頂角は７０度よ
りも９０度、９０度よりも１２０度のほうが好ましく１
５０度以上になると本発明の効果は減少し、配光特性、
例えば面状発光体から出光する光が出光面に降ろした法
線方向から４５度以内に実質的に集中している場合は、
頂角は１００度〜１４０度が良い。In the present invention, the apex angle (9 in the figure) of the apex of the above-mentioned sheet is preferably 70 to 150 degrees. The more preferable range of the apex angle 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,
When a refractive index n = 1.59) is used, the apex angle is preferably 90 degrees rather than 70 degrees and 120 degrees rather than 90 degrees.
When the temperature exceeds 50 degrees, the effect of the present invention decreases and the light distribution characteristics,
For example, when the light emitted from the planar light-emitting body is substantially concentrated within 45 degrees from the normal direction dropped on the light-emitting surface,
The vertical angle is preferably 100 to 140 degrees.
【００１８】又、前記したシ−トのプリズムの、頂点か
らのそれぞれの斜辺の長さが実質的に等しいものを用い
ることが、本発明の効果を向上させる上で特に好まし
い。又、シートに形成した多数の直線状プリズムの分布
状態は、表面から出光される光によって直線状プリズム
の間隔が視認されにくくする上で、互いに平行で隣り合
った直線状プリズムの頂稜と頂稜の間隔は１０〜１００
０μm であることが好ましい。そして前記シ−トの直線
状プリズム部の厚さ（図中ｔ２）は前記した頂稜の頂角
及び頂稜と頂稜の間隔で決まるが、多数の直線状プリズ
ム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（図中Ｔ）は１０〜３０００μm 、好ましくは５
０〜１０００μm が良い。また、同一面に形成する直線
状プリズムは、より効果的には同一形状のものが良い。Further, it is particularly preferable to use the above-mentioned sheet prism in which the hypotenuses from the apex have substantially the same length in order to improve the effect of the present invention. In addition, the distribution state of a large number of linear prisms formed on the sheet makes it difficult for the light emitted from the surface to visually recognize the interval between the linear prisms. The ridge spacing is 10-100
It is preferably 0 μm. The thickness (t2 in the figure) of the linear prism portion of the sheet is determined by the apex angle of the apex ridge and the interval between the apex ridges described above. It is necessary to have a thickness (t1 in the figure) to maintain such a positional relationship, and this t1 is preferably thin in order to reduce the light transmittance and the thickness of the backlight. From the viewpoint of strength, the total thickness of the sheet (T in the figure) is 10 to 3000 μm, preferably 5
0 to 1000 μm is preferable. Further, the linear prisms formed on the same surface should have the same shape more effectively.
【００１９】本発明で用いるシートを成形する方法は、
例えば熱プレスによる金型成型加工、エンボス加工、鋳
型加工、化学処理、印刷等の方法で実質的に同形の直線
状プリズム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 forming the sheet used in the present invention is as follows.
For example, a method capable of forming a plurality of linear prisms having substantially the same shape in parallel with each other at fine intervals by a method such as mold forming processing by hot pressing, embossing processing, mold processing, chemical processing, printing, etc. I wish I had it. 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.
【００２０】本発明では、前記した透光性フィルム（シ
ート）（ベースフィルム）の上にベースフィルムと異質
の透光性材質（例えばアクリル系樹脂などの紫外線硬化
樹脂等）を前記した印刷等の方法によって直線状凸型を
微細な間隔で多数有するように形成したものを用いる。In the present invention, a translucent material (for example, an ultraviolet curable resin such as an acrylic resin) different from the base film is formed on the translucent film (sheet) (base film) described above such as printing. What is formed by a method so as to have a large number of linear convex shapes at minute intervals is used.
【００２１】液晶ディスプレイは、その表示面に降ろし
た法線方向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 normal direction lowered to the display surface becomes larger, so that the brightness in the vicinity of the normal direction is important in practical use. Further, since the viewfinder can be seen only from the normal direction dropped on the display surface, practically, the brightness in the vicinity of the normal direction is important.
【００２２】本発明で、前記したように、出光面側が微
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
指向性が現われる。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 surface side is 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 in the direction of the normal line lowered to the light emitting surface,
Compared to the case where the sheet is not provided, the brightness is increased, an angle with respect to the normal line lowered to the light exit surface,
For example, the luminance measured similarly from the direction of 40 degrees has a larger reduction rate than the luminance measured in the normal direction (for example, almost 50% of the luminance measured in the normal direction).
It is understood that the above-mentioned light directivity appears.
【００２３】次に、本発明における作用を図面に基づい
て更に詳述する。図１０は本発明で、直線状プリズムを
有するシートを用いた場合の、シ−トの任意のプリズム
の断面に任意の点から入射する光線を光線追跡した一例
の図である。Next, the operation of the present invention will be described in more detail with reference to the drawings. FIG. 10 is a diagram showing an example of ray tracing of a ray incident from an arbitrary point on the cross section of an arbitrary prism of the sheet in the case of using a sheet having a linear prism in the present invention.
【００２４】プリズムの頂角を２α（度）とし、透光性
材料からなるシ−トの屈折率をｎ、空気の屈折率を１と
すると、臨界角θｃ（度）は θｃ＝ｓｉｎ-1（１／ｎ） １）光線が角度θ1 （度）で入射し、角度θ6 （度）で
出射する場合（図１０（ａ）） ｓｉｎθ1 ＝ｎ×ｓｉｎθ2 θ3 ＝９０°−α−θ2 ｎ×ｓｉｎθ3 ＝ｓｉｎθ4 （ただしθ3 ≦θｃのと
き） θ5 ＝９０°−α−θ4 θ6 ＝θ5 ２）光線が角度θ1 （度）で入射し、角度θ8 （度）で
出射する場合（図１１（ｂ）） ｓｉｎθ1 ＝ｎ×ｓｉｎθ2 θ3 ＝９０°−α−θ2 θ4 ＝θ3 （ただしθ3 ＞θｃのとき） θ5 ＝２α−θ4 ｎ×ｓｉｎθ5 ＝ｓｉｎθ6 （ただしθ5 ≦θｃのと
き） θ7 ＝９０°−α−θ6 θ8 ＝−θ7 このような計算を行うことによって、透光性材料からな
るシ−トに用いる材料の屈折率、プリズムの頂角がわか
れば、バックライトの出光面から出光する光線の透光性
材料からなるシ−トへの入射角から出射角を求めること
が出来る。尚、図１０には示さなかったが、前記条件に
よっては、入射光線はプリズム内部を２回以上反射する
場合もあるし、バックライトの出光面に戻る場合もあ
る。When the apex angle of the prism is 2α (degrees), the refractive index of the sheet made of a light transmissive material is n, and the refractive index of air is 1, the critical angle θc (degrees) is θc = sin −1. (1 / n) 1) ray angle theta 1 (incident in degrees), when emitted at the angle theta 6 (degrees) (FIG. 10 (a)) sinθ 1 = n × sinθ 2 θ 3 = 90 ° -α -θ 2 n × sinθ 3 = sinθ 4 ( provided that when the θ 3 ≦ θc) θ 5 = 90 ° -α-θ 4 θ 6 = θ 5 2) beams are incident at an angle theta 1 (degrees), the angle theta When the light is emitted at 8 degrees (FIG. 11B) sin θ 1 = n × sin θ 2 θ 3 = 90 ° −α−θ 2 θ 4 = θ 3 (where θ 3 > θc) θ 5 = 2α −θ 4 n × sin θ 5 = sin θ 6 (when θ 5 ≦ θc) θ 7 = 90 ° −α−θ 6 θ 8 = −θ 7 By performing such a calculation, a transparent material is formed. Material used for sheet Refractive index, knowing the apex angle of the prism, back from the light exit surface of the light made of a translucent material of light rays exiting sheet - the angle of incidence on the bets can be determined emission angle. Although not shown in FIG. 10, depending on the above conditions, the incident light beam may be reflected twice or more inside the prism or may return to the light emitting surface of the backlight.
【００２５】例えば、図１２に示したように前記シ−ト
をポリカ−ボネート（屈折率ｎ＝１．５９）で作り、プ
リズムの頂角を９０度にした場合に於いては、入射角０
度で前記シ−トに入射した光線はプリズム内部で全反射
し、バックライトへ戻される。バックライトへ戻された
光線はバックライト内部で一部は吸収され、一部は反射
し再びバックライトの出光面より出光する。For example, when the sheet is made of polycarbonate (refractive index n = 1.59) as shown in FIG. 12 and the apex angle of the prism is 90 degrees, the incident angle is 0.
The light beam incident on the sheet at a time is totally reflected inside the prism and returned to the backlight. The light rays returned to the backlight are partially absorbed inside the backlight, partially reflected, and emitted again from the light emitting surface of the backlight.
【００２６】従って、この様にバックライトから出光し
た光が前記シ−トのプリズム内部で全反射して再びバッ
クライトへ戻される場合には、バックライト内部での光
の吸収が少ない程、またバックライト内部での光の反射
率が高い程すなわちバックライトの出光面以外の面が反
射率の高い反射板で覆われている程、効率の良いバック
ライトになる。Therefore, when the light emitted from the backlight is totally reflected inside the prism of the sheet and returned to the backlight again, the less light is absorbed inside the backlight, the more The higher the reflectance of light inside the backlight, that is, the more the surface other than the light emitting surface of the backlight is covered with the reflector having high reflectance, the more efficient the backlight becomes.
【００２７】また、入射角３０度で前記シ−トに入射し
た光線は出射角０．５度で前記シ−トより出光し、入射
角６０度で前記シ−トに入射した光線は出射角２５．７
度で前記シ−トより出光する。そして、この場合のバッ
クライトの出光面から出光する光は実質的に前記出光面
に降ろした法線方向からの角度がほぼ４０度以内に最も
集中し、その結果、前記法線方向から測定した輝度が、
前記シ−トを配さない場合に比較して増加する。A light ray incident on the sheet at an incident angle of 30 degrees is emitted from the sheet at an emission angle of 0.5 degree, and a light ray incident on the sheet at an incident angle of 60 degrees is emitted at the emission angle. 25.7
Light is emitted from the sheet at a certain degree. Then, in this case, the light emitted from the light emitting surface of the backlight is substantially most concentrated within an angle of about 40 degrees from the normal direction dropped onto the light emitting surface, and as a result, the light is measured from the normal direction. The brightness is
The number is increased as compared with the case where the sheet is not provided.
【００２８】同様に、図１３に示したように前記シ−ト
をポリカ−ボネートで作り、プリズムの頂角を１２０度
にした場合に於いては、入射角０度で前記シ−トに入射
した光線は出射角２２．７度で前記シ−トより出光し、
入射角３０度で前記シ−トに入射した光線は出射角１
１．２度で前記シ−トより出光し、入射角６０度で前記
シ−トに入射した光線は出射角３４．８度で前記シ−ト
より出光する。そして、この場合のバックライトの出光
面から出光する光は実質的に前記出光面に降ろした法線
方向からの角度がほぼ４４度以内に最も集中し、その結
果、前記法線方向から測定した輝度が、前記シ−トを配
さない場合に比較して増加する。Similarly, when the sheet is made of polycarbonate as shown in FIG. 13 and the apex angle of the prism is 120 degrees, the sheet is incident on the sheet at an incident angle of 0 degree. The emitted light is emitted from the sheet at an emission angle of 22.7 degrees,
A light ray that enters the sheet at an incident angle of 30 degrees has an exit angle of 1
A light beam emitted from the sheet at 1.2 degrees and a light beam incident on the sheet at an incident angle of 60 degrees exits from the sheet at an emission angle of 34.8 degrees. Then, the light emitted from the light emitting surface of the backlight in this case is substantially most concentrated within an angle of about 44 degrees from the normal direction dropped onto the light emitting surface, and as a result, the light is measured from the normal direction. The brightness increases as compared with the case where the sheet is not provided.
【００２９】この様に、前記シ−トのプリズムの頂角を
コントロ−ルすることによって、面状発光体の出光面か
ら出光する光の指向性を制御することが出来る。As described above, by controlling the apex angle of the prism of the sheet, it is possible to control the directivity of the light emitted from the light emitting surface of the planar light emitting body.
【００３０】[0030]
【発明の効果】本発明は比較的小型で、充分な輝度を得
られ、出光面に降ろした法線方向に対しては消費電力−
輝度変換効率が大なバックライトとして使用できる。EFFECTS OF THE INVENTION The present invention is comparatively small in size, can obtain sufficient brightness, and consumes less power in the direction normal to the light exit surface.
It can be used as a backlight with high luminance conversion efficiency.
【００３１】[0031]
【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５又は６に示すような厚さ２．０mmの長方形導光
板（２２５mm×１２７mmｍ）（図中１）の短手の端部
に、直径４．８mmの太さの冷陰極蛍光管（ハリソン電機
株式会社製ノ−マル管）（図中４）を配置し、導光板に
接する部分に２mmのスリットを持つ筒型アルミ反射器の
内面に光拡散フィルムをラミネ−トしたもので覆いスリ
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。一方導光板面上に被覆する光拡散物
質（チタンホワイトを含む塗料）（図中６）は、円形の
ドットパタ−ンを１．２mmピッチでスクリ−ン印刷した
ものであり下記の条件で作成して用いた。光拡散物質の
被覆率が、最小の地点（冷陰極蛍光管側）で６％、最大
の地点で８０％、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作図した。EXAMPLES Next, the present invention will be described in more detail with reference to Comparative Examples and Examples. As shown in FIG. 5 or 6, at the short edge of a rectangular light guide plate (225 mm × 127 mm) (2.0 mm thick) (1 in the figure), a cold cathode fluorescent tube with a thickness of 4.8 mm (Harrison Electric (Normal tube manufactured by Co., Ltd.) (4 in the figure) is placed, and a light diffusion film is laminated on the inner surface of a cylindrical aluminum reflector that has a slit of 2 mm in the part that contacts the light guide plate, and light is emitted from the slit. The light is arranged so as to enter the light guide plate from the end portion of the light guide plate. On the other hand, the light-diffusing substance (paint containing titanium white) (6 in the figure) coated on the surface of the light guide plate is a circular dot pattern screen-printed at a pitch of 1.2 mm, and is prepared under the following conditions. Used. The plots were made so that the coverage of the light diffusing substance was 6% at the minimum point (cold cathode fluorescent tube side), 80% at the maximum point, and these ratios were sequentially increased in the middle.
【００３２】さらに、導光板の出光面側に光拡散フィル
ム（辻本電機製作所Ｄ−２０４）（図中２）を１枚配置
した。又、導光板の光拡散物質を被覆した面側に光拡散
反射板（図中３）を配置した。冷陰極管に、インバ−タ
より３０KHz の交番電圧をかけて一定電流で駆動させた
ときの面輝度を、輝度計（トプコンＢＭ−７）により視
野角２度、出光面に降ろした法線方向に対して、出光面
から輝度計までの距離４０cmで測定したところ１９２cd
/m2 であった（比較例１）。Further, one light diffusion film (Tsujimoto Denki Seisakusho D-204) (2 in the figure) was arranged on the light emitting surface side of the light guide plate. Further, a light diffusing reflection plate (3 in the figure) is arranged on the surface side of the light guide plate coated with the light diffusing substance. The surface brightness when an alternating voltage of 30 KHz was applied from the inverter to the cold-cathode tube and it was driven with a constant current, the viewing angle was 2 degrees with the brightness meter (Topcon BM-7), and the normal direction was lowered to the light exit surface On the other hand, when measured at a distance of 40 cm from the light emitting surface to the luminance meter, 192 cd
It was / m 2 (Comparative Example 1).
【００３３】前記光拡散フィルムの上に、市販の、ポリ
カ−ボネートからなる頂角が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−トを直線状プリズムが外側
になるようにバックライトの出光面側に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３０７cd/m2 であった（実施例１）。On the light-diffusing film, there are a large number of commercially available linear prisms made of polycarbonate and having parallel apex angles of 90 degrees, and the distance between adjacent apexes of the linear prisms. The same apparatus and conditions as in Comparative Example 1 except that one sheet having a thickness of 360 μm processed to have a space of 350 μm is arranged on the light emitting surface side of the backlight so that the linear prism is on the outside. The measured luminance was 307 cd / m 2 (Example 1).
【００３４】更に直線状プリズムが内側になるようにバ
ックライトの出光面側に１枚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１５cd/m
2 であった（比較例２）。Further, the brightness was 15 cd / m as measured by operating under the same apparatus and conditions as in Example 1 except that one linear prism was placed on the light emitting surface side of the backlight so that the linear prism was inside.
It was 2 (Comparative Example 2).
【００３５】更にプリズム状の突起の頂角を７０度にし
た直線状プリズムを用いた以外は実施例１と同一の装
置、条件、で操作し、測定した輝度は２４５cd/m2 であ
った（実施例２）。Further, the brightness was 245 cd / m 2 as measured by operating under the same apparatus and conditions as in Example 1 except that a linear prism having a prism-shaped protrusion with an apex angle of 70 ° was used. Example 2).
【００３６】更にプリズム状の突起の頂角を１２０度に
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３３０cd/m2 であった（実施例３）。Further, the brightness was 330 cd / m 2 as measured by operating under the same apparatus and conditions as in Example 1 except that the apex angle of the prismatic protrusions was set to 120 ° (Example 3).
【００３７】前記光拡散フィルムの上に、厚さ５０μm
のＰＥＴのベースフィルムの上に印刷法によって紫外線
硬化樹脂（アクリル系樹脂）で多数の直線状凸部を、凸
部の底面の幅が５０μm 、底面から凸部の高さが２５μ
m 、凸部と凸部の間隔が５０μm になるように形成した
シートを直線状凸部が外側になるようにバックライトの
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２３５cd/m2 であった
（実施例４）。A thickness of 50 μm is formed on the light diffusion film.
A number of linear protrusions made of UV curable resin (acrylic resin) on the PET base film by a printing method, the bottom width of the protrusions is 50 μm, and the height of the protrusions from the bottom is 25 μm.
m, the same apparatus as Comparative Example 1 except that one sheet formed so that the interval between the convex portions is 50 μm is arranged on the light emitting surface side of the backlight so that the linear convex portions are on the outside,
Operating under the conditions, the measured luminance was 235 cd / m 2 (Example 4).
【００３８】次に、バックライトの配光特性を調べるた
めに、比較例１、実施例１、実施例２、について、冷陰
極管に、インバ−タより３０KHz の交番電圧をかけて一
定電流で駆動させたときの面輝度を、輝度計（トプコン
ＢＭ−７）により視野角２度で、図１４に示すように出
光面に降ろした法線方向に対しての角度を０度から７０
度まで変化させ、出光面から輝度計までの距離４０cmで
測定したときの輝度の値を図１５に示した。この図か
ら、本発明のバックライトを用いると輝度が増加し、光
の指向性が顕著であることが判る。Next, in order to examine the light distribution characteristics of the backlight, in Comparative Example 1, Example 1 and Example 2, an alternating voltage of 30 KHz was applied from the inverter to the cold cathode tube at a constant current. With respect to the surface luminance when driven, a luminance meter (Topcon BM-7) has a viewing angle of 2 degrees, and an angle with respect to a normal direction dropped to the light emitting surface from 0 degree to 70 degrees as shown in FIG.
FIG. 15 shows the value of the luminance when measured at a distance of 40 cm from the light emitting surface to the luminance meter by changing the degree up to 40 degrees. From this figure, it can be seen that when the backlight of the present invention is used, the brightness is increased and the directivity of light is remarkable.
【図１】１灯型エッジライト方式のバックライトの一例
を示す斜視図FIG. 1 is a perspective view showing an example of a one-light type edge light type backlight.
【図２】１灯型エッジライト方式のバックライトの一例
を示す断面図FIG. 2 is a cross-sectional view showing an example of a one-light type edge light type backlight.
【図３】２灯型エッジライト方式のバックライトの一例
を示す斜視図FIG. 3 is a perspective view showing an example of a two-light type edge light type backlight.
【図４】２灯型エッジライト方式のバックライトの一例
を示す断面図FIG. 4 is a cross-sectional view showing an example of a two-light type edge light type backlight.
【図５】本発明の一実施態様の斜視図FIG. 5 is a perspective view of an embodiment of the present invention.
【図６】本発明の一実施態様の断面図FIG. 6 is a cross-sectional view of one embodiment of the present invention.
【図７】本発明の一実施態様の斜視図FIG. 7 is a perspective view of an embodiment of the present invention.
【図８】本発明の一実施態様の断面図FIG. 8 is a cross-sectional view of one embodiment of the present invention.
【図９】本発明で用いるシ−トの斜視図FIG. 9 is a perspective view of a sheet used in the present invention.
【図１０】光線追跡の一例を示す図FIG. 10 is a diagram showing an example of ray tracing.
【図１１】光線追跡の一例を示す図FIG. 11 is a diagram showing an example of ray tracing.
【図１２】プリズム頂角９０度の場合の例を示す図FIG. 12 is a diagram showing an example in which the prism vertical angle is 90 degrees.
【図１３】プリズム頂角１２０度の場合の例を示す図FIG. 13 is a diagram showing an example in which the prism vertical angle is 120 degrees.
【図１４】本発明で用いた測定方法の概念図FIG. 14 is a conceptual diagram of a measuring method used in the present invention.
【図１５】出射光輝度の角度分布を示す図FIG. 15 is a diagram showing an angular distribution of emitted light brightness.
１：導光板 ２：光拡散板 ３：反射板 ４：線状光源 ５：反射器 ６：光拡散物質 ７：直線状プリズムを持つシ−ト ８：直線状頂稜 ９：プリズムの頂角 １０：バックライト １１：輝度計 １２：出光面に降ろした法線方向に対しての角度 １３：出光面に降ろした法線 1: Light guide plate 2: Light diffusing plate 3: Reflecting plate 4: Linear light source 5: Reflector 6: Light diffusing substance 7: Sheet having linear prism 8: Linear apex ridge 9: Vertical angle of prism 10 : Backlight 11: Luminance meter 12: Angle with respect to the direction of the normal line on the light exit surface 13: Normal line on the light exit surface
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成７年７月４日[Submission date] July 4, 1995
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００２[Name of item to be corrected] 0002
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【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１灯型エッジライト方
式、図３に示すように透光性の導光板の対向する二端部
に、蛍光管のような線状光源を併設する２灯型エッジラ
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又は図４に示すように、導光板の一方の面に
この導光板材料よりも屈折率が大きい光拡散物質を部分
的に被覆し、その面のほぼ全面を光拡散反射板で覆うよ
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, a one-lamp type edge light system 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. 1, and as shown in FIG. A two-lamp type edge light system in which a linear light source such as a fluorescent tube is provided at two opposite ends of a light guide plate is often used. In the case of this edge light method, as shown in FIG. 2 or FIG. 4, one surface of the light guide plate is partially covered with a light diffusing substance having a refractive index higher than that of the material of the light guide plate, and almost the entire surface is covered. Many are arranged so as to be covered with a light diffusion reflector.
Claims (6)
に、拡散反射率の大きい顔料を含んでなる光拡散物質を
部分的に被覆し、その面を光反射板で覆い、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、同一面に微細な間
隔で直線状頂稜を持つプリズムを、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−トであっ
て、前記シートは透光性フィルム上に前記フィルムとは
異質の透光性材質で直線状頂稜を持つプリズムを形成し
たものであり、このシートを導光板の出光面側に頂稜面
が外側になるように１枚以上配置したパネル用バックラ
イト。1. A light-diffusing substance containing a pigment having a large diffuse reflectance is partially coated on one wide surface of a light guide plate made of a translucent material, and the surface is covered with a light-reflecting plate. In a backlight for a panel having a linear light source near at least one side surface of a light guide plate, a prism having linear apexes at fine intervals on the same surface, in which apexes are substantially parallel In a sheet made of a light-transmitting material having a large number of the above, the sheet is a light-transmitting film on which a prism having a linear apex is formed by a light-transmitting material different from the film, A backlight for a panel, in which one or more sheets of this sheet are arranged on the light emitting surface side of the light guide plate so that the top ridge surface is on the outside.
るシ−トの順に配置した請求項１記載のバックライト。2. The backlight according to claim 1, wherein a light guide plate, a light diffusion sheet, and a sheet made of a translucent material are arranged in this order.
隣合うシートの頂稜がほぼ直交する状態で配置した請求
項１又は２記載のバックライト。3. A plurality of sheets made of a translucent material are used,
The backlight according to claim 1 or 2, wherein the top edges of adjacent sheets are arranged so as to be substantially orthogonal to each other.
トを用いる請求項１〜３いずれか記載のバックライト。4. A seam having an apex with an apex angle of 70 to 150 degrees.
The backlight according to claim 1, wherein the backlight is used.
０００μm であるシ−トを用いる請求項１〜４いずれか
記載のバックライト。5. The distance between adjacent apexes is 10 to 1
The backlight according to any one of claims 1 to 4, wherein a sheet having a size of 000 µm is used.
請求項１〜５いずれか記載のバックライト。6. The backlight according to claim 1, wherein the light diffusing substance contains silicon dioxide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7140544A JPH08111106A (en) | 1995-06-07 | 1995-06-07 | Backlight |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7140544A JPH08111106A (en) | 1995-06-07 | 1995-06-07 | Backlight |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3275022A Division JP3030792B2 (en) | 1991-08-22 | 1991-09-27 | Backlight |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08111106A true JPH08111106A (en) | 1996-04-30 |
Family
ID=15271150
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7140544A Pending JPH08111106A (en) | 1995-06-07 | 1995-06-07 | Backlight |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08111106A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05127159A (en) * | 1991-09-27 | 1993-05-25 | Tosoh Corp | Back light |
-
1995
- 1995-06-07 JP JP7140544A patent/JPH08111106A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05127159A (en) * | 1991-09-27 | 1993-05-25 | Tosoh Corp | Back light |
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