JP3500725B2 - Backlight - Google Patents
BacklightInfo
- Publication number
- JP3500725B2 JP3500725B2 JP23686294A JP23686294A JP3500725B2 JP 3500725 B2 JP3500725 B2 JP 3500725B2 JP 23686294 A JP23686294 A JP 23686294A JP 23686294 A JP23686294 A JP 23686294A JP 3500725 B2 JP3500725 B2 JP 3500725B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- guide plate
- light guide
- sheet
- reflector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Liquid Crystal (AREA)
- Planar Illumination Modules (AREA)
- Light Guides In General And Applications Therefor (AREA)
Description
【発明の詳細な説明】Detailed Description of the Invention
【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。このようなエッジライト方式の場合には、
図２に示すように、導光板の一方の広い面に光拡散物質
を部分的に被覆し、その面の全面を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, 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 case of such edge light method,
As shown in FIG. 2, it is often arranged such that one wide surface of the light guide plate is partially covered with a light diffusing substance, and the entire surface is covered with a reflection plate.
【０００３】特に近時、これらワ−ドプロセッサー、パ
ソコンの性能向上のため、小型化、視認性の向上がより
一層望まれており、バックライトに於いては液晶表示パ
ネルの表示領域に対応するバックライトの発光領域に対
する導光板の最大外形をより小さくして小型化を達成し
ようとしている。Particularly in recent years, in order to improve the performance of these word processors and personal computers, further miniaturization and improvement of visibility are desired, and in backlight, it corresponds to the display area of a liquid crystal display panel. We are trying to achieve miniaturization by making the maximum outer shape of the light guide plate smaller than the light emitting area of the backlight.
【０００４】しかし、バックライトの発光領域に対する
導光板の面積（最大外形）をより小さくしたものは、導
光板の線状光源を近接させた端部近傍に、導光板端部と
ほぼ平行な位置に高輝度部（輝線）が発生し、発光領域
内での輝度均一性が悪化して視認性が悪くなる問題があ
った。However, in the case where the area (maximum outer shape) of the light guide plate with respect to the light emitting area of the backlight is made smaller, a position substantially parallel to the end portion of the light guide plate is provided in the vicinity of the end portion where the linear light source of the light guide plate is brought close. There is a problem in that a high-luminance portion (bright line) is generated, and the luminance uniformity in the light emitting region is deteriorated, resulting in poor visibility.
【０００５】輝線が発生する原因は、図３に示したよう
に線状光源（図中４）を覆った光反射器（図中５）の端
部を導光板に接着するために用いた両面テ−プ等の接着
層（図中９）が、導光板内に入射して本来は全反射を繰
り返すはずの光線を光拡散反射してしまうためである。
又、導光板に両面テ−プ等の接着層を使用しない場合で
も、図４に示したように線状光源を覆った反射器の端部
と導光板との間に構造上隙間が出来ると、反射器の端部
で反射した光線が導光板の端面部以外の面（導光板の上
面又は下面）から入射して、その光線が導光板内での全
反射条件から外れ、輝線が発生する原因となっていた。
この様な輝線は光反射器の導光板の出光面側の端部近傍
から最も高輝度な状態で発せられていた。The cause of the bright line is that both ends of the light reflector (5 in the figure) covering the linear light source (4 in the figure) are bonded to the light guide plate as shown in FIG. This is because an adhesive layer (9 in the figure) such as a tape diffuses and reflects a light beam that is incident on the light guide plate and should normally repeat total reflection.
Further, even if an adhesive layer such as a double-sided tape is not used on the light guide plate, a gap may be structurally formed between the end of the reflector covering the linear light source and the light guide plate as shown in FIG. , The light ray reflected by the end portion of the reflector enters from a surface other than the end surface portion of the light guide plate (the upper surface or the lower surface of the light guide plate), and the light ray deviates from the condition of total reflection in the light guide plate, and a bright line is generated. It was the cause.
Such a bright line was emitted in the highest brightness state from the vicinity of the end of the light guide plate of the light reflector on the light emitting surface side.
【０００６】このような問題を解決するため、光源を覆
ったカバ−と導光板との接合部に光吸収手段を設ける方
法が提案されているが（実開平４−４２６８８号公報参
照）、光吸収手段で光源から出光した光の一部が吸収さ
れてしまうため、光を有効に利用できないなどの問題が
あった。In order to solve such a problem, a method has been proposed in which a light absorbing means is provided at a joint between a light source cover and a cover (see Japanese Utility Model Laid-Open No. 4-42688). Part of the light emitted from the light source is absorbed by the absorbing means, which causes a problem that the light cannot be effectively used.
【０００７】[0007]
【発明が解決しようとする課題】本発明の目的は、高輝
度で発光領域に対して外形寸法が可能な限り小さくかつ
視認性が良好なバックライトを提供することにある。SUMMARY OF THE INVENTION It is an object of the present invention to provide a backlight which has high brightness and has a small external dimension with respect to a light emitting region and has good visibility.
【０００８】[0008]
【課題を解決するための手段】本発明者等は、導光板
の、線状光源が近接した端部付近の構造と、導光板出光
面の輝度分布について種々の検討を行った結果、エッジ
ライト方式のバックライトに於いて、光反射器の光拡散
シ−ト側の端部を工夫することにより、高輝度で有効発
光面積に対して外形寸法が可能な限り小さくかつ視認性
が良好なバックライトとなることを見出した。Means for Solving the Problems The present inventors have conducted various studies on the structure of the light guide plate near the end where the linear light sources are close to each other and the luminance distribution of the light exit surface of the light guide plate. In the system backlight, by devising the end of the light reflector on the side of the light diffusion sheet, the backlight has high brightness and an external dimension as small as possible with respect to the effective light emitting area and good visibility. I found it to be a light.
【０００９】即ち本発明は、透光性材料からなり広い面
から出光させる機能を有する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と、前記線状光源を覆う
光反射器と、前記導光板の出光面側に少なくとも１枚の
光拡散シ−トと導光板の出光面側とは反対側の裏面側に
光反射板又はシ−トを有するバックライトに於いて、導
光板の出光面側であって光反射器と光拡散シ−トとの近
接部分の少なくとも一部分に、反射面を導光板側とした
光反射性物質を配置したバックライトに関するものであ
る。That is, according to the present invention, a linear light source, which is made of a translucent material and has a function of emitting light from a wide surface, is adjacent to at least one side surface end portion of the light guide plate, and a light reflector that covers the linear light source. A light guide plate having at least one light diffusing sheet on the light emitting surface side of the light guide plate and a light reflecting plate or sheet on the back surface side opposite to the light emitting surface side of the light guide plate. The present invention relates to a backlight in which a light-reflecting substance having a reflecting surface on the light guide plate side is arranged on at least a part of the light-exiting surface side of the light reflector and the light diffusing sheet.
【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５は、本発明の一実施態様の断面図であ
る。図中１は導光板であり、光を効率よく通過させる物
質からなるものであればよく、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が用いられ
る。FIG. 5 is a sectional view of an embodiment of the present invention. In the figure, reference numeral 1 denotes a light guide plate, which may be made of a substance that allows light to efficiently pass therethrough, and quartz, glass, translucent natural or synthetic resin such as acrylic resin is used.
【００１２】導光板１の一方の広い面には、導光板に入
光した光を拡散させる機能を持たせるが、この拡散機能
は光拡散エレメントを同面に形成するなどして持たせ
る。導光板面に形成する光拡散エレメント（図中６に例
示した）は、例えば、ＴｉＯ2、BaSO4 、ＳｉＯ2 などの
光散乱性物質を施すなどして形成するが、これは、拡散
反射率が大きい顔料を含んだ塗料、印刷インキ等をスク
リ−ン印刷等の方法で導光板面上にドット状又はライン
状などに印刷するなどして行う。その他、導光板の表面
を粗面化するか、小孔を開けるか、小突起を付与するな
どして導光板の表面そのものに光拡散性を付与しても良
い。これら光拡散エレメントは、導光板において光源か
らの距離が大となるに従って、導光板の単位面積当たり
の光拡散性が順次大となるように、ドット状又はライン
状などの形状に施される。又、導光板中に屈折率の異な
る微細な粒子等が多数存在する状態にして導光板の内部
そのものに光拡散性を付与しても良い。One wide surface of the light guide plate 1 has a function of diffusing light entering the light guide plate, and this diffusion function is provided by forming a light diffusing element on the same surface. The light diffusing element (illustrated by 6 in the figure) formed on the surface of the light guide plate is formed by applying a light scattering material such as TiO 2 , BaSO 4 , SiO 2 or the like, which has a diffuse reflectance. It is carried out by printing a paint containing a large pigment, a printing ink or the like in a dot shape or a line shape on the light guide plate surface by a method such as screen printing. In addition, the surface of the light guide plate may be roughened, small holes may be formed, or small protrusions may be provided to impart light diffusing property to the surface of the light guide plate itself. These light diffusing elements are formed in a dot shape or a line shape so that the light diffusing property per unit area of the light guide plate gradually increases as the distance from the light source increases in the light guide plate. Further, light diffusivity may be imparted to the inside of the light guide plate itself by making a large number of fine particles having different refractive indexes exist in the light guide plate.
【００１３】４は線状光源（棒状光源）で、導光板の周
囲の少なくとも一端面に近接して配置されており、好ま
しい態様としては、導光板の端部に光が入光するように
線状光源の中心軸が同端面とほぼ平行となるように配置
し、線状光源の、導光板の端部と相対する面以外の表面
を光反射器５で覆う状態で配置することである。線状光
源４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、有効発光面積の輝度分布の均一性の面及び省電力の
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 denotes a linear light source (rod-shaped light source), which is arranged in the vicinity of at least one end face around the light guide plate, and in a preferred mode, a line is provided so that light enters the end portion of the light guide plate. The light source 5 is arranged such that the central axis of the linear light source is substantially parallel to the same end surface, and the surface of the linear light source other than the surface facing the end of the light guide plate is covered with the light reflector 5. The linear light source 4 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 an electrode is preferable in terms of uniformity of luminance distribution of an effective light emitting area and power saving. It is preferable that the length of the uniform light emitting portion excluding the portion is substantially equal to the length of the end portion of the light guide plate adjacent thereto.
【００１４】光反射器５は、線状光源と相対する面が光
を反射させる性質のものであれば良く、反射面が鏡面反
射板又はシ−トである場合は、銀、アルミニウム、白
金、ニッケル、クロム等からなる材質で、好ましくはポ
リエステルなどのプラスチックフィルム基材に又は金属
板に銀、アルミニウム等を蒸着またはスパッタリングに
より表面コ−トしたものである。The light reflector 5 has only to have a property that the surface facing the linear light source reflects light. When the reflection surface is a specular reflection plate or sheet, silver, aluminum, platinum, A material made of nickel, chromium, or the like, preferably a plastic film base material such as polyester or a metal plate on which silver, aluminum or the like is surface-coated by vapor deposition or sputtering.
【００１５】また、反射面が光拡散反射板又はシ−トで
ある場合は、ポリエステルなどの樹脂に光拡散性物質
（例えばＴｉＯ2 、ＢａＳＯ4 、ＳｉＯ2 など）を混入
させたもの、ポリエステルなどの樹脂を発泡させて光拡
散性を付与したもの、Ａｌ板などの板に前記光拡散性物
質を塗布したものなどがあるが、入射した光線を拡散反
射する性質があれば良くその材質は特に限定されない。
線状光源を覆う光反射器の端部は、線状光源からの光線
を効率良く反射して導光板の端面に入射させるために、
図５に示した様に導光板の出光面側と出光面側とは反対
側の端部に配置されることが通常である。When the reflecting surface is a light diffusing reflector or sheet, a resin such as polyester mixed with a light diffusing substance (eg, TiO 2 , BaSO 4 , SiO 2 etc.), polyester, etc. There is a resin having a light diffusivity imparted by foaming the resin, a plate such as an Al plate coated with the light diffusing substance, and the like, but the material is particularly required as long as it has a property of diffusing and reflecting an incident light ray. Not limited.
The end portion of the light reflector that covers the linear light source efficiently reflects the light beam from the linear light source and makes it incident on the end surface of the light guide plate.
As shown in FIG. 5, it is usual that the light guide plate is arranged at the light emitting surface side and the end portion on the opposite side to the light emitting surface side.
【００１６】２は光拡散シ−トで、導光板面より出光し
た光を散乱させて通過させるものである。光拡散シ−ト
の材質は光を透過させる性質があれば良く特に限定され
ないが、ポリエステル、ポリカ−ボネイトなどの高分子
材料又はガラスなどの無機材料でも良い。また、光拡散
シ−トの光を散乱させる作用は、光拡散シ−トの表面を
粗面にして光を拡散させる作用を付与する、光拡散シ−
トの表面に光拡散性のある物質をコ−ティングする、光
拡散シ−ト内部に屈折率の異なる微粒子が多数存在する
状態にするなどして付与すれば良い。さらに、光を拡散
すると共に光に指向性を付与する構造を持つシートも用
いられる。本発明ではこの光拡散シ−トを一枚又は複数
枚用いる。Reference numeral 2 is a light diffusing sheet which scatters the light emitted from the light guide plate surface and allows it to pass through. The material of the light diffusion sheet is not particularly limited as long as it has a property of transmitting light, but may be a polymer material such as polyester or polycarbonate or an inorganic material such as glass. Further, the action of scattering the light of the light diffusion sheet imparts the action of making the surface of the light diffusion sheet a rough surface and diffusing the light.
It may be applied by coating a substance having a light diffusing property on the surface of the sheet, or by making a state in which a large number of fine particles having different refractive indexes exist inside the light diffusing sheet. Further, a sheet having a structure that diffuses light and imparts directivity to light is also used. In the present invention, one or more sheets of this light diffusion sheet are used.
【００１７】光反射板又はシ−ト３は導光板の出光面と
は相対する導光板の面のほぼ全面を覆うように配置す
る。反射板又はシ−トは、光を反射させるものであれば
良く、鏡面反射板又はシ−トである場合は、銀、アルミ
ニウム、白金、ニッケル、クロム等からなる材質で、好
ましくはポリエステルなどのプラスチックフィルム基材
又は金属板に銀、アルミニウム等を蒸着またはスパッタ
リングにより表面コ−トしたものである。又、反射板又
はシ−トが光拡散反射板又はシ−トである場合は、ポリ
エステルなどの樹脂に光拡散性物質（例えばＴｉＯ2 、
ＢａＳＯ4 、ＳｉＯ2 など）を混入させたもの、ポリエ
ステルなどの樹脂を発泡させて光拡散性を付与したも
の、Ａｌ板などの板に前記光拡散性物質を塗布したもの
などがあるが、入射した光線を拡散反射する性質があれ
ば良くその材質は特に限定されない。The light reflection plate or sheet 3 is arranged so as to cover almost the entire surface of the light guide plate facing the light exit surface of the light guide plate. The reflection plate or sheet may be any one as long as it reflects light. When the reflection plate or sheet is a specular reflection plate or sheet, the material is silver, aluminum, platinum, nickel, chromium or the like, preferably polyester or the like. It is a plastic film substrate or a metal plate with a surface coating of silver, aluminum or the like by vapor deposition or sputtering. When the reflection plate or sheet is a light diffusion reflection plate or sheet, a resin such as polyester is used as a light diffusion substance (for example, TiO 2 ,
BaSO 4 , SiO 2 etc.), a resin such as polyester foamed to impart light diffusivity, or a plate such as an Al plate coated with the light diffusing substance. The material is not particularly limited as long as it has the property of diffusing and reflecting the generated light rays.
【００１８】本発明の特徴である線状光源を覆った光反
射器の導光板出光面側の端部と光拡散シ−ト側の端部の
状態は、図５に示すように、導光板の出光面側でこれら
両端部の近接部分において、反射面が導光板側に相対す
るように光反射性物質（図中７）が配置された状態であ
る。この様な状態にすることによって、図７に示す様な
光反射器の端部付近から導光板の出光面の法線方向に対
して斜め方向に多く出射される輝線の原因となる光線
を、光反射性物質によって反射し、再び導光板内部へ戻
して光を有効に利用できるので更に高輝度化が達成でき
るのである。As shown in FIG. 5, the state of the light guide plate light emitting surface side end and the light diffusion sheet side end of the light reflector which covers the linear light source, which is a feature of the present invention, is as shown in FIG. The light-reflecting substance (7 in the figure) is arranged so that the reflecting surface faces the light guide plate side in the vicinity of these both ends on the light emitting surface side. By making such a state, a light ray causing a lot of bright lines emitted from the vicinity of the end portion of the light reflector as shown in FIG. 7 obliquely with respect to the normal direction of the light exit surface of the light guide plate, Since the light is reflected by the light-reflecting substance and returned to the inside of the light guide plate to effectively utilize the light, higher brightness can be achieved.
【００１９】なお、前記した光反射性物質を配置する部
分は、光反射器の端部と光拡散シ−トの端部が相対する
（近接する）部分の大部分、特に全部であることが全て
の輝線を減少させ、かつ、従来は輝線となって外部へ放
出した又は光吸収手段で吸収された光線を有効に利用で
きる上で最も好ましい状態であるが、部分的にでも前述
した部分を持てばその部分の輝線は減少し、かつ、その
分だけ高輝度化が達成される。The portion where the above-mentioned light-reflecting substance is arranged is most, especially all of the portion where the end portion of the light reflector and the end portion of the light diffusion sheet face each other (close to each other). This is the most preferable state in which all the bright lines are reduced and the light rays that have been emitted to the outside as a bright line and are absorbed by the light absorbing means can be effectively used, but the above-mentioned part is partially applied. If it is held, the bright lines in that portion are reduced, and higher brightness is achieved accordingly.
【００２０】光反射性物質７は、光を反射させるもので
あれば良く、鏡面反射板又はシ−トである場合は、銀、
アルミニウム、白金、ニッケル、クロム等からなる材質
で、好ましくはポリエステルなどのプラスチックフィル
ム基材又は金属板に銀、アルミニウム等を蒸着またはス
パッタリングにより表面コ−トしたものである。The light-reflecting substance 7 may be any substance as long as it reflects light, and in the case of a specular reflector or a sheet, silver,
A material made of aluminum, platinum, nickel, chromium or the like, preferably a plastic film base material such as polyester or a metal plate on which silver, aluminum or the like is surface-coated by vapor deposition or sputtering.
【００２１】又、光反射性物質が光拡散反射板又はシ−
トである場合は、ポリエステルなどの樹脂に光拡散性物
質（例えばＴｉＯ2 、ＢａＳＯ4 、ＳｉＯ2 など）を混
入させたもの、ポリエステルなどの樹脂を発泡させて光
拡散性を付与したもの、Ａｌ板などの板に前記光拡散性
物質を塗布したものなどがあるが、入射した光線を拡散
反射する性質があれば良くその材質は特に限定されな
い。光反射性物質の鏡面反射率又は拡散反射率は５０%
以上であることが好ましく、従来は輝線となって外部へ
放出したか又は光吸収手段で吸収された光線を有効に利
用する上で７０%以上、より好ましくは８０% 以上であ
る。Further, the light-reflecting substance is a light diffusing reflector or sheet.
In the case of the resin, a resin such as polyester mixed with a light diffusing substance (for example, TiO 2 , BaSO 4 , SiO 2 etc.), a resin such as polyester foamed to impart light diffusing property, Al There is a plate such as a plate coated with the light diffusing substance, but the material is not particularly limited as long as it has a property of diffusing and reflecting an incident light beam. The specular reflectance or diffuse reflectance of the light reflective material is 50%
It is preferably not less than 70%, more preferably not less than 80% in order to effectively utilize the light rays that have been emitted to the outside as a bright line or absorbed by the light absorbing means.
【００２２】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 structure 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.
【００２３】光反射性物質が空気層を介して導光板面上
に配置されていることが好ましい。この様な構成にする
ことによって、光の利用効率を向上させより高輝度なバ
ックライトが得られる。It is preferable that the light-reflecting substance is disposed on the surface of the light guide plate via the air layer. With such a configuration, it is possible to improve the light use efficiency and obtain a backlight with higher brightness.
【００２４】光反射性物質がテ−プ状であり光拡散シ−
トの表面又は裏面に接着するか、又は、光拡散シ−トの
表面又は裏面に光反射性物質を密着することが好まし
い。この様な構成にすることによって、機構的な安定性
が得られる。The light-reflecting material is in the form of a tape and has a light-diffusing sheet.
It is preferable that the light-reflecting substance is adhered to the front surface or the back surface of the sheet or the light-reflecting material is adhered to the surface or the back surface of the light diffusion sheet. With such a structure, mechanical stability can be obtained.
【００２５】光反射性物質の光反射面の裏面側が暗黒色
であることが好ましい。この様な構成にすることによっ
て、僅かに漏れ出た輝線の原因となる迷光を光反射面の
裏面側の暗黒色面で捕捉することができる。The back side of the light reflecting surface of the light reflecting material is preferably dark black. With such a configuration, stray light that causes slightly leaked bright lines can be captured by the dark black surface on the back surface side of the light reflecting surface.
【００２６】又、光反射器の導光板出光面側の端部に相
対する導光板出光面とは反対側の導光板部分が空気層を
介して光拡散反射板又はシ−トで覆われていることが好
ましい。この様な構成にすることによって、導光板出光
面とは反対側の面から出光する輝線の原因となる光線の
発生を防止できる。Further, the light guide plate portion opposite to the light guide plate light emitting surface side end portion of the light reflector facing the light guide plate light emitting surface side is covered with a light diffusing reflection plate or sheet via an air layer. Is preferred. With such a configuration, it is possible to prevent the generation of a light ray that causes a bright line emitted from the surface opposite to the light exit surface of the light guide plate.
【００２７】[0027]
【発明の効果】本発明は小型で、有効発光領域に対して
外形寸法が可能な限り小さく高輝度でかつ視認性が良好
なバックライトとして使用できる。INDUSTRIAL APPLICABILITY The present invention can be used as a backlight which is small in size, has a small external dimension with respect to an effective light emitting region, has a high luminance, and has a good visibility.
【００２８】[0028]
【実施例】次に実施例及び比較例で本発明を更に詳述す
る。図５に示すような厚さ４mmの長方形アクリル板（２
０５mm×１６０mm、旭化成株式会社製デラグラスＡ）の
短手の端部に、直径３mm長さ１８０mm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、導光板の裏
面上には光散乱物質（チタニア）を含むインクを円形の
ドットパタ−ンで１mmピッチでスクリ−ン印刷し、スク
リ−ン版下は、下記の条件でＣＡＤを用いて作成した。
光拡散物質の被覆率が、最小の地点（冷陰極蛍光管近傍
で後述する直線状プリズムを有するシ−トの冷陰極蛍光
管側直下）で２０ %、最大の地点（導光板の光源最遠
部）で９５ %、その中間では被覆率が最小の地点からこ
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 Examples and Comparative Examples. A rectangular acrylic plate with a thickness of 4 mm (2
A cold-cathode fluorescent tube (made by Harrison Electric Co., Ltd.) with a diameter of 3 mm and a length of 180 mm is arranged at the short end of 05 mm × 160 mm, Delaglass made by Asahi Kasei Co. A), and on the back surface of the light guide plate. An ink containing a light-scattering substance (titania) was screen-printed with a circular dot pattern at a pitch of 1 mm, and a screen printing plate was prepared using CAD under the following conditions.
The light diffusing substance coverage is 20% at the minimum point (just below the cold cathode fluorescent tube side of the sheet having a linear prism described later near the cold cathode fluorescent tube), and the maximum point (the light source farthest from the light guide plate). (Part) was 95%, and in the middle, the ratio was sequentially increased from the point where the coverage was the minimum, and the plot was made.
【００２９】厚さ０．１３mmのポリエステルからなる白
色の光拡散反射シ−ト（ＩＣＩ社製メリネックス 329）
は導光板の光散乱物質を被覆した面の全面を空気層を介
して覆うように配置した。冷陰極蛍光管の外周はＰＥＴ
（ポリエステル）フィルムに銀を蒸着した厚さ０．０５
mmの銀フィルム（株式会社麗光製、鏡面反射率９３%）
で覆い、銀フィルムの導光板の出光面側の端部は幅２．
５mmで厚さ０．１６mmの両面接着テ−プ（株式会社寺岡
製作所 WPT-No750F)で導光板出光面に接着し、銀フィル
ムの導光板の出光面側とは反対側の端部は前記した光拡
散反射シ−トの導光板と相対していない面に前記した両
面接着テ−プで接着した。White light diffusion reflection sheet made of polyester having a thickness of 0.13 mm (Melinex 329 manufactured by ICI)
Was arranged so as to cover the entire surface of the light guide plate coated with the light-scattering material with an air layer in between. The outer circumference of the cold cathode fluorescent tube is PET
(Polyester) film with silver deposited thickness: 0.05
mm silver film (manufactured by Reiko Co., Ltd., specular reflectance 93%)
And the width of the edge of the light guide plate of the silver film on the light emitting surface side is 2.
A 5 mm thick 0.16 mm double-sided adhesive tape (Teraoka Seisakusho WPT-No750F) was used to adhere to the light exit surface of the light guide plate, and the end of the silver film opposite to the light exit surface side of the light guide plate was described above. The surface of the light diffusive reflection sheet not facing the light guide plate was bonded with the double-sided adhesive tape described above.
【００３０】厚さ０．１８mmのポリカ−ボネ−トからな
る光拡散シ−ト（ＧＥ社製 8B36 ）は粗面側が導光板側
とは反対側になるようにして、導光板の出光面のほぼ全
面を覆うように空気層を介して配置した。尚、光拡散シ
−トは銀フィルムの端部から２mm離した地点から配置し
た。A light diffusion sheet (8B36 manufactured by GE) made of polycarbonate having a thickness of 0.18 mm is arranged so that the rough surface side is opposite to the light guide plate side and the light exit surface of the light guide plate is It was placed with an air layer in between so as to cover almost the entire surface. The light diffusion sheet was placed at a position 2 mm away from the edge of the silver film.
【００３１】冷陰極管に、インバ−タより３０ KHzの交
番電圧をかけて一定電流（菅電流６mA）で駆動させたと
きの面輝度を、輝度計（トプコンBM-8）により導光板の
法線方向から測定した。この時の有効発光面（図５中光
散乱物質を施した導光板の部分に対応する部分）内の９
９点（均等割り）平均輝度は１５００cd/m2 であった。
そして導光板の冷陰極管を近接させた端部近傍に異常発
光部（輝線）が観測された。尚、輝線の観測方法はバッ
クライトの出光面に対する法線方向から目視によって観
測した。輝線部分の輝度を輝度計（トプコンBM-8）によ
り導光板の法線方向から測定したところ、輝線部分内の
最高輝度は２７００cd/m2 であった（比較例１）。The surface brightness of a cold cathode fluorescent lamp when an alternating voltage of 30 KHz was applied from the inverter and driven at a constant current (tube current of 6 mA) was measured by a luminance meter (Topcon BM-8) to determine the light guide plate method. It was measured from the line direction. 9 in the effective light emitting surface at this time (the portion corresponding to the portion of the light guide plate provided with the light scattering material in FIG. 5)
The average brightness of 9 points (equal division) was 1500 cd / m 2 .
Then, an abnormal light emitting portion (bright line) was observed in the vicinity of the end portion of the light guide plate where the cold cathode tubes were brought close to each other. The method of observing the bright line was visually observed from the direction normal to the light emitting surface of the backlight. When the luminance in the bright line portion was measured with a luminance meter (Topcon BM-8) from the normal line direction of the light guide plate, the maximum luminance in the bright line portion was 2700 cd / m 2 (Comparative Example 1).
【００３２】次に、光拡散シ−トと銀フィルムの端部と
の間に幅２ｍｍの暗黒色のテ−プを接着した以外は比較
例１と同一の装置、条件で測定した平均輝度は１３５０
cd/m2 であった。そして導光板の冷陰極管を近接させた
端部近傍の異常発光部（輝線）は比較例１の状態のよう
には観測されず、輝線部分内の最高輝度は１６５０cd/m
2 であった（比較例２）。Next, the average brightness measured under the same conditions and conditions as in Comparative Example 1 except that a dark black tape having a width of 2 mm was adhered between the light diffusion sheet and the end of the silver film. 1350
It was cd / m 2 . The abnormal light emitting portion (bright line) near the end of the cold cathode tube of the light guide plate was not observed as in the case of Comparative Example 1, and the maximum brightness in the bright line portion was 1650 cd / m 2.
It was 2 (Comparative Example 2).
【００３３】次に、光拡散シ−トと銀フィルムの端部と
の間に幅２mmｍの銀フィルムを反射面が導光板側になる
ように接着した以外は比較例１と同一の装置、条件で測
定した平均輝度は１４５０cd/m2 であった。そして導光
板の冷陰極管を近接させた端部近傍の異常発光部（輝
線）は比較例１の状態のようには観測されず、輝線部分
内の最高輝度は１６００cd/m2 であった（実施例１）。Next, the same apparatus and conditions as in Comparative Example 1 were used except that a silver film having a width of 2 mm was adhered between the light diffusion sheet and the end of the silver film so that the reflection surface was on the light guide plate side. The average luminance measured in 1 was 1450 cd / m 2 . The abnormal light emitting portion (bright line) in the vicinity of the end where the cold cathode tube of the light guide plate was brought close to was not observed as in the state of Comparative Example 1, and the maximum brightness in the bright line portion was 1600 cd / m 2 ( Example 1).
【００３４】次に、光拡散シ−トと銀フィルムの端部と
の間に幅３mmの銀フィルムを反射面が導光板側になるよ
うに光反射器の端部と光拡散シ−トに接着して、導光板
との間に空気層が存在する状態にした以外は比較例１と
同一の装置、条件で測定した平均輝度は１５５０cd/m2
であった。そして導光板の冷陰極管を近接させた端部近
傍の異常発光部（輝線）は比較例１の状態のようには観
測されず、輝線部分内の最高輝度は１５７０cd/m2 であ
った（実施例２）。Next, a silver film having a width of 3 mm is provided between the light diffusing sheet and the end of the silver film on the end of the light reflector and the light diffusing sheet so that the reflection surface is on the light guide plate side. The average brightness measured under the same conditions and conditions as in Comparative Example 1 was 1550 cd / m 2 except that an air layer was present between the light-guide plate and the adhesive.
Met. The abnormal light emitting portion (bright line) near the end of the light guide plate where the cold cathode tube was brought close to was not observed as in the state of Comparative Example 1, and the maximum brightness in the bright line portion was 1570 cd / m 2. Example 2).
【００３５】次に、図６に示す様に光拡散シ−トの裏面
（導光板側）に幅２mmの銀フィルムを反射面が導光板側
になるように接着し、光拡散シ−トを銀フィルムの端部
から実質的に０mmの地点から配置した以外は比較例１と
同一の装置、条件で測定した平均輝度は１５５０cd/m2
であった。そして導光板の冷陰極管を近接させた端部近
傍の異常発光部（輝線）は比較例１の状態のようには観
測されず、輝線部分内の最高輝度は１５６０cd/m2 であ
った（実施例３）。Next, as shown in FIG. 6, a silver film having a width of 2 mm is adhered to the back surface (light guide plate side) of the light diffusion sheet so that the reflection surface is on the light guide plate side, and the light diffusion sheet is formed. The average luminance measured under the same conditions and conditions as in Comparative Example 1 was 1550 cd / m 2 except that the silver film was placed at a point substantially 0 mm from the edge.
Met. The abnormal light emitting portion (bright line) near the end of the cold guide tube of the light guide plate was not observed as in the case of Comparative Example 1, and the maximum brightness in the bright line portion was 1560 cd / m 2 ( Example 3).
【００３６】次に、光拡散シ−トの銀フィルムを接着し
た裏面部分に対応する表面側に幅２mmの暗黒色テ−プを
接着した以外は実施例２と同一の装置、条件で測定した
平均輝度は１５５０cd/m2 であった。そして導光板の冷
陰極管を近接させた端部近傍の異常発光部（輝線）は比
較例１の状態のようには観測されず、輝線部分内の最高
輝度は１５６０cd/m2 であった、又バックライトを液晶
表示装置に組み込んだ時に発生する迷光を防止すること
ができた（実施例４）。Next, the measurement was performed using the same equipment and conditions as in Example 2 except that a dark black tape having a width of 2 mm was adhered to the front surface side corresponding to the back surface portion to which the silver film of the light diffusion sheet was adhered. The average brightness was 1550 cd / m 2 . The abnormal light emitting portion (bright line) near the end of the cold cathode tube of the light guide plate was not observed as in the state of Comparative Example 1, and the maximum brightness in the bright line portion was 1560 cd / m 2 . In addition, it was possible to prevent stray light generated when the backlight was incorporated into the liquid crystal display device (Example 4).
【００３７】次に、光反射器の導光板出光面側の端部に
相対する導光板出光面とは反対側の面が空気層を介して
鏡面反射シ−トで覆われるように、銀フィルムの導光板
の出光面側とは反対側の端部が光拡散反射シ−トの導光
板と相対している面に両面接着テ−プで接着した以外は
実施例１と同一の装置、条件で測定した平均輝度は１４
４５cd/m2 であった。そして導光板の冷陰極管を近接さ
せた端部近傍の異常発光部（輝線）は実施例１よりも観
測され、輝線部分内の最高輝度は１７００cd/m2 であっ
た（実施例５）Next, a silver film is formed so that the surface of the light reflector opposite to the light exit surface of the light guide plate facing the light exit surface side of the light guide plate is covered with a specular reflection sheet through an air layer. The same apparatus and conditions as in Example 1 except that the end portion of the light guide plate on the side opposite to the light emitting surface side is adhered to the surface of the light diffusive reflection sheet facing the light guide plate with a double-sided adhesive tape. The average brightness measured in 14
It was 45 cd / m 2 . An abnormal light emitting portion (bright line) near the end of the light guide plate where the cold cathode tube was brought closer was observed more than in Example 1, and the maximum brightness in the bright line portion was 1700 cd / m 2 (Example 5).
【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】従来の一実施態様のバックライトの光源付近の
断面図FIG. 3 is a cross-sectional view near a light source of a backlight according to a conventional embodiment.
【図４】従来の一実施態様のバックライトの光源付近の
断面図FIG. 4 is a sectional view around a light source of a backlight according to a conventional embodiment.
【図５】本発明の一実施態様のバックライトの断面図FIG. 5 is a sectional view of a backlight according to an embodiment of the present invention.
【図６】本発明の一実施態様のバックライトの断面図FIG. 6 is a sectional view of a backlight according to an embodiment of the present invention.
【図７】本発明の効果の概念を示す断面図FIG. 7 is a sectional view showing the concept of the effect of the present invention.
１：導光板 ２：光拡散又はシ−ト ３：反射板又はシ−ト ４：線状光源 ５：反射器 ６：光拡散エレメント ７：光反射性物質 ８：輝線の原因となる光線 ９：接着層 １０：従来輝線の原因となっていた光線 1: Light guide plate 2: Light diffusion or sheet 3: Reflector or sheet 4: Linear light source 5: Reflector 6: Light diffusion element 7: Light reflective material 8: Light rays that cause bright lines 9: Adhesive layer 10: Rays that have conventionally been the cause of bright lines
Claims (4)
から出光させる機能を有する導光板と、該導光板の少な
くとも一側面にこれに近接して設けられた線状光源と、
該線状光源を覆う、鏡面反射板若しくは鏡面反射シート
又は光拡散反射板若しくは光拡散反射シートからなる光
反射器（以下「光反射器」と称す）と、前記導光板の出
光面側に設けられた少なくとも１枚の光拡散シ−トと、
前記導光板の出光面側とは反対の側に設けられた、鏡面
反射板若しくは光拡散反射板（以下「光反射板」と称
す）又は鏡面反射シート若しくは光拡散反射シート（以
下「光反射シ−ト」と称す）を有するバックライトに於
いて、前記線状光源を覆う光反射器の導光板出光面側の
端部を、導光板の出光面端部に接着するとともに、該光
反射器の導光板出光面側の端部と光拡散シ−トとの近接
部分の少なくとも一部分に、反射面を導光板側とした、
鏡面反射板若しくは鏡面反射シート又は光拡散反射板若
しくは光拡散反射シートからなる光反射性物質（以下
「光反射性物質」と称す）を空気層を介して導光板の出
光面上に配置したバックライト。1. A light guide plate made of a plate-shaped light-transmitting material and having a function of emitting light from one wide surface, and a linear light source provided on at least one side surface of the light guide plate in the vicinity thereof.
A specular reflection plate or a specular reflection sheet that covers the linear light source
Alternatively, a light reflector (hereinafter referred to as "light reflector" ) formed of a light diffusion reflection plate or a light diffusion reflection sheet, and at least one light diffusion sheet provided on the light exit surface side of the light guide plate,
Mirror surface provided on the side opposite to the light emitting surface side of the light guide plate
Reflector or diffuse diffuser (hereinafter referred to as " light reflector ")
Be) or specular reflection sheet or a light diffuse reflection sheet (hereinafter
In a backlight having a " light reflection sheet " below , while adhering an end of the light reflector covering the linear light source on the light exit side of the light guide plate to the end of the light exit face of the light guide plate. , The light guide plate side has a reflecting surface at least at a part of the vicinity of the end portion of the light reflector on the light guide plate light output surface side and the light diffusion sheet ,
Specular reflection plate or specular reflection sheet or light diffusion reflection plate
A light-reflecting material (hereinafter referred to as a light-diffusing reflection sheet)
A backlight in which a "light-reflecting substance") is arranged on the light emitting surface of the light guide plate through an air layer.
面に接着又は密着した状態である請求項１記載のバック
ライト。2. The backlight according to claim 1, wherein the light-reflecting substance is in a state of being adhered or adhered to the front surface or the back surface of the light diffusion sheet.
である請求項１又は２記載のバックライト。3. The backlight according to claim 1, wherein the back surface side of the light reflecting surface of the light reflecting material is dark black.
された部分に相対する導光板出光面とは反対側の部分に
空気層を介して光拡散反射板又は光拡散反射シ−トを配
置した請求項１〜３いずれか記載のバックライト。4. A light diffuse reflection plate or light diffuse reflection through an air layer at a portion opposite to the light guide plate light emitting surface opposite to a portion where the light reflector end portion of the light guide plate light emitting surface side is arranged. The backlight according to claim 1, wherein a sheet is arranged.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23686294A JP3500725B2 (en) | 1994-09-30 | 1994-09-30 | Backlight |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23686294A JP3500725B2 (en) | 1994-09-30 | 1994-09-30 | Backlight |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08101311A JPH08101311A (en) | 1996-04-16 |
| JP3500725B2 true JP3500725B2 (en) | 2004-02-23 |
Family
ID=17006906
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23686294A Expired - Fee Related JP3500725B2 (en) | 1994-09-30 | 1994-09-30 | Backlight |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3500725B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4049235B2 (en) * | 1999-09-10 | 2008-02-20 | 株式会社エンプラス | Surface light source device and image display device including the surface light source device |
| JP3690298B2 (en) | 2001-02-23 | 2005-08-31 | ソニーケミカル株式会社 | Liquid crystal display element |
| JP4001736B2 (en) * | 2001-10-23 | 2007-10-31 | アルプス電気株式会社 | Surface light emitting device and liquid crystal display device |
| WO2004076917A1 (en) * | 2003-01-29 | 2004-09-10 | Mitsubishi Rayon Co., Ltd. | Area light source |
| JP6154694B2 (en) * | 2013-05-15 | 2017-06-28 | 株式会社エス・ケー・ジー | Light emitting device |
| JP2020129305A (en) * | 2019-02-08 | 2020-08-27 | 株式会社グルマンディーズ | Decorative tool for portable information terminal |
-
1994
- 1994-09-30 JP JP23686294A patent/JP3500725B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08101311A (en) | 1996-04-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |