JPH0627325A - Surface light source device - Google Patents
Surface light source deviceInfo
- Publication number
- JPH0627325A JPH0627325A JP4179765A JP17976592A JPH0627325A JP H0627325 A JPH0627325 A JP H0627325A JP 4179765 A JP4179765 A JP 4179765A JP 17976592 A JP17976592 A JP 17976592A JP H0627325 A JPH0627325 A JP H0627325A
- Authority
- JP
- Japan
- Prior art keywords
- light
- sheet
- light source
- guide plate
- transparent prism
- 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
- Light Guides In General And Applications Therefor (AREA)
- Optical Elements Other Than Lenses (AREA)
- Liquid Crystal (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は面光源装置に関する。特
に、液晶が用いられている表示装置のバックライトに好
適な面光源装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light source device. In particular, the present invention relates to a surface light source device suitable for a backlight of a display device using liquid crystal.
【０００２】[0002]
【従来の技術】ワープロ、パソコン、液晶テレビ等の液
晶を用いた厚みの薄い表示装置は、液晶自体が発光しな
いために、通常、バックライトを使用している。このバ
ックライトは厚みが薄く、しかも、表示装置の面をほぼ
均一に照射する必要がある。かかるバックライトには、
通常、面光源装置が使用される。この面光源装置として
は種々あるが、最も多く使用されている面光源装置の構
造は、導光板の端面に光源を設け、この光源から照射さ
れる光を導光板の表面や導光板に取り付けられた板の表
面からほぼ均一に出光させるものである。2. Description of the Related Art A thin display device using liquid crystal, such as a word processor, a personal computer, and a liquid crystal television, usually uses a backlight because the liquid crystal itself does not emit light. This backlight needs to be thin and to illuminate the surface of the display device almost uniformly. Such backlights include
Usually, a surface light source device is used. Although there are various types of surface light source devices, the most widely used structure of the surface light source device is to provide a light source on the end face of the light guide plate and attach the light emitted from this light source to the surface of the light guide plate or the light guide plate. The light is emitted almost uniformly from the surface of the plate.
【０００３】近年、薄型やカラー化に対応するために、
表示装置のバックライトの輝度向上の要求が高まってい
る。そこで、同じ光源で輝度を向上させるためには、面
光源装置の出光させる方向を規制して、使用者の見る方
向に効率よく光を出光させ、輝度を向上させることが必
要である。In recent years, in order to support thinning and colorization,
There is an increasing demand for improving the brightness of the backlight of a display device. Therefore, in order to improve the brightness with the same light source, it is necessary to regulate the light emitting direction of the surface light source device so that the light is efficiently emitted in the direction viewed by the user to improve the brightness.
【０００４】更に詳細に説明すると、一般に、厚みの薄
い導光板の端面に光源を設け、この端面から光を入光さ
せると、空気と導光板との屈折率の差により、光は全反
射を繰り返し、導光板から外に殆ど出ない。そこで、面
光源装置では導光板の裏面にビーズ等のドットをスクリ
ーン印刷等により乱反射層を施し、この裏面に反射板を
取り付け、導光板の裏面に当たる光を乱反射層の面で乱
反射させ、この乱反射した光を直接または反射板で反射
させて、導光板の外側に出光させるのである。More specifically, generally, when a light source is provided on the end face of a thin light guide plate and light is incident from this end face, the light undergoes total reflection due to the difference in refractive index between air and the light guide plate. Repeatedly, almost never go out of the light guide plate. Therefore, in the surface light source device, dots such as beads are provided on the back surface of the light guide plate by screen printing or the like, and a diffuser plate is attached to this back surface so that the light hitting the back surface of the light guide plate is diffusely reflected by the surface of the diffuse reflection layer, and this diffuse reflection is performed. The reflected light is reflected directly or by the reflection plate to be emitted to the outside of the light guide plate.
【０００５】しかし、導光板の端面に設けられた光源か
ら照射された光は、通常、図４に示すように、導光板の
表面に対して非常に小さい角度で出光する。即ち、極め
て指向性が強い。このことを図４を参照しながら、更に
詳細に説明すると、図４において１０１は裏面にドット
印刷を施した透明な導光板であり、この導光板１０１の
裏面に反射板１０２を設け、この導光板１０１の端面に
線状の光源１０３を設けたものであり、この光源１０３
から放射された光は導光板１０１の中を通り、導光板１
０１の裏面に施された乱反射層の面で乱反射され、導光
板１０１から直接出るか、反射板１０２に反射されて導
光板１０１の表面から出る。そのときのＡ点の光は、図
４のＢのように、導光板１０１との角度が小さく極めて
方向性の強い光である。However, the light emitted from the light source provided on the end surface of the light guide plate normally exits at a very small angle with respect to the surface of the light guide plate, as shown in FIG. That is, the directivity is extremely strong. This will be described in more detail with reference to FIG. 4. In FIG. 4, 101 is a transparent light guide plate with dot printing on the back surface, and a reflection plate 102 is provided on the back surface of the light guide plate 101. A light source 103 having a linear shape is provided on the end surface of the light plate 101.
The light emitted from the light guide plate 101 passes through the light guide plate 101.
The light is diffusedly reflected on the surface of the diffused reflection layer provided on the back surface of 01 and directly emitted from the light guide plate 101, or reflected from the light guide plate 102 and emitted from the surface of the light guide plate 101. The light at the point A at that time is light having a small angle with the light guide plate 101 and extremely strong directivity, as shown in FIG. 4B.
【０００６】しかし、このように導光板との角度が小さ
い方向で使用者が見ることは稀であるから、この光の出
光する角度を変えることが必要である。この方向性を改
良するために、図５に示すように、導光板１０１の表面
に拡散板１０４を設けると、図５のＣに示すように、指
向性が緩やかになるが、未だ、不十分である。However, since it is rare for the user to see in such a direction that the angle with the light guide plate is small, it is necessary to change the angle at which this light is emitted. If a diffusion plate 104 is provided on the surface of the light guide plate 101 as shown in FIG. 5 in order to improve this directionality, the directivity becomes gentle as shown in C of FIG. 5, but it is still insufficient. Is.
【０００７】かかる欠点を改良するものとして、特開平
２−１７号公報に記載あるように、この導光板の表面
に、平らな傾斜面からなる凹凸条を設けた透明プリズム
フィルムまたはシートを、凹凸条の面を導光板に当接さ
せて設けた面光源装置が知られている。即ち、この面光
源装置は指向性の強い光を使用者が見る方向に透明プリ
ズムフィルムまたはシートの凹凸条の平らな傾斜面で変
え、透明プリズムフィルムまたはシートの凹凸条と反対
側の面、即ち、透明プリズムフィルムまたはシートの表
面から出光させるものである。In order to improve such a defect, as described in Japanese Patent Application Laid-Open No. 2-17, a transparent prism film or sheet having an uneven strip formed of a flat inclined surface on the surface of the light guide plate is provided. 2. Description of the Related Art A surface light source device is known in which a strip surface is provided in contact with a light guide plate. That is, this surface light source device changes the light having a strong directivity in the direction viewed by the user by the flat inclined surface of the uneven strip of the transparent prism film or sheet, that is, the surface opposite to the uneven strip of the transparent prism film or sheet, that is, The light is emitted from the surface of the transparent prism film or sheet.
【０００８】[0008]
【発明が解決しようとする課題】しかし、この面光源装
置を発明者が実験したところ、透明なプリズムフィルム
またはシートを設けることにより、光の方向を使用者の
見る方向に効率よく変えて出光させることができるが、
導光板の裏面にスクリーン印刷等で施された乱反射層が
見えるという問題がある。この乱反射層が見える面光源
装置の上に液晶を用いた表示装置を置くと、表示装置の
画面がひどく見難くなる。又、指向性が強過ぎると、見
る方向が少し変わっただけで見えなくなるという問題が
ある。However, as a result of experiments conducted by the inventor of this surface light source device, a transparent prism film or sheet is provided so that the direction of light can be efficiently changed to the direction viewed by the user. But you can
There is a problem that the diffused reflection layer formed by screen printing or the like can be seen on the back surface of the light guide plate. When a display device using liquid crystal is placed on the surface light source device where the irregular reflection layer can be seen, the screen of the display device becomes extremely difficult to see. Further, if the directivity is too strong, there is a problem in that the viewer cannot see the object even if the viewing direction is slightly changed.
【０００９】上記公報では、導光板の出光面を梨地状に
して拡散性を持たせることを提案しているが、光の指向
性が改善されるが、乱反射層が見えたり、表示装置が見
難いということは殆ど改善されない。そこで、本発明の
目的は、導光板からの指向性の強い光の方向を改善する
ことにより光の効率を向上させると同時に、乱反射層を
見えなくした面光源装置を提供することである。In the above publication, it is proposed that the light exit surface of the light guide plate be satin-finished to have diffusivity. However, although the directivity of light is improved, the diffuse reflection layer can be seen and the display device can be seen. Hardness is hardly improved. Therefore, an object of the present invention is to provide a surface light source device that improves the efficiency of light by improving the direction of light having a strong directivity from the light guide plate and at the same time makes the diffuse reflection layer invisible.
【００１０】[0010]
【課題を解決するための手段】本発明は上記問題を解決
し、上記目的を達成するためになしたものであって、裏
面に乱反射層が施された透明な導光板の端面に線状の光
源が設けられ、この導光板の表面に、平らな傾斜面から
なる凹凸条が設けられている透明プリズムフィルムまた
はシートが凹凸条の面を導光板に当接させて設けられ、
この導光板の裏面に反射板が設けられている面光源装置
において、透明プリズムフィルムまたはシートの凹凸条
と反対側の面に光拡散層が設けられているものである。SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and achieves the above objects, and a linear light guide plate is provided on the end face of a transparent light guide plate having a back surface provided with a diffuse reflection layer. A light source is provided, and on the surface of the light guide plate, a transparent prism film or sheet provided with an uneven line formed of a flat inclined surface is provided by bringing the surface of the uneven line into contact with the light guide plate.
In a surface light source device in which a reflection plate is provided on the back surface of this light guide plate, a light diffusion layer is provided on the surface of the transparent prism film or sheet opposite to the concavo-convex stripes.
【００１１】本発明において、透明プリズムフィルムま
たはシートとは、ガラスや透明な合成樹脂等の透明な物
質を、一面に平らな傾斜面からなる凹凸条を設けてフィ
ルムまたはシートに成形させたものである。特に、合成
樹脂製の透明プリズムフィルムまたはシートが好適であ
る。この合成樹脂製の透明プリズムフィルムまたはシー
トの最も好ましい製造方法はポリカーボネート、ポリメ
チルメタクリル、ポリエステル等の透明な樹脂を表面に
凹凸条を設けながら押し出して形成する方法である。In the present invention, the transparent prism film or sheet is formed by molding a transparent substance such as glass or transparent synthetic resin into a film or sheet having a concavo-convex strip having a flat inclined surface on one surface. is there. In particular, a transparent prism film or sheet made of synthetic resin is suitable. The most preferable method for producing the transparent prism film or sheet made of synthetic resin is a method in which a transparent resin such as polycarbonate, polymethylmethacrylate or polyester is extruded while providing uneven ridges on the surface.
【００１２】本発明においてはこの透明プリズムフィル
ムまたはシートの凹凸条と反対側の面に光拡散層を設け
ているが、このように光拡散層を設ける方法は種々あ
る。その例を示すと、炭酸カルシウム粉末、酸化チタン
粉末、亜鉛華、アルミナ粉末、シリカ粉末、白土等の無
機粉末や、ガラスビーズやガラス繊維等の光を拡散させ
る光拡散物質を塗料や接着剤の中に混入させ、この塗料
や接着剤を透明プリズムフィルムまたはシートの上に塗
布する方法がある。In the present invention, a light diffusing layer is provided on the surface of the transparent prism film or sheet on the side opposite to the concavo-convex stripes, but there are various methods for providing the light diffusing layer. For example, calcium carbonate powder, titanium oxide powder, zinc white, alumina powder, silica powder, inorganic powder such as clay, and light diffusion substances such as glass beads and glass fibers for diffusing light are used as paints or adhesives. There is a method in which the paint or the adhesive is mixed in and applied onto a transparent prism film or sheet.
【００１３】又、別な方法としては、光拡散物質を含む
組成物をフィルムやシートに成形し、このフィルムまた
はシートを透明プリズムフィルムやシートの表面に接着
剤で貼り付けたり、熱プレス方法で貼り付けたりする方
法がある。又、別な方法としては、上記透明プリズムフ
ィルムまたはシートを製造するときに、光拡散物質を含
む組成物をフィルムやシートに同時に押し出して、両者
を一体に成形する方法がある。即ち、共押出法で製造す
る方法がある。この光拡散物質を入れる量は適宜でよい
が、好ましい範囲は、透明合成樹脂１００重量部に対し
て、光拡散物質を１０〜５０重量部である。As another method, a composition containing a light diffusing substance is formed into a film or sheet, and the film or sheet is attached to the surface of a transparent prism film or sheet with an adhesive, or by a heat pressing method. There is a method of pasting. Another method is to simultaneously extrude a composition containing a light diffusing substance into a film or sheet at the time of producing the transparent prism film or sheet to integrally form the both. That is, there is a method of manufacturing by a coextrusion method. The amount of the light diffusing substance to be added may be appropriate, but a preferable range is 10 to 50 parts by weight of the light diffusing substance with respect to 100 parts by weight of the transparent synthetic resin.
【００１４】本発明においてはこの透明プリズムフィル
ムまたはシートの表面と光拡散層とを光学的に密着させ
るとよい。ここで、光学的に密着させるとは、透明プリ
ズムフィルムまたはシートから出た光が直接光散乱層に
入ることを意味するものであって、この中間に例えば空
気層等を設けないことである。このようにすることによ
り、光の反射が少なくなり光の損失がないので好まし
い。この透明プリズムフィルムまたはシートの表面に光
拡散層を光学的に密着させる方法は、熱プレス法、共押
出法等公知の方法が使用できる。In the present invention, it is preferable that the surface of the transparent prism film or sheet and the light diffusing layer are optically brought into close contact with each other. Here, the optical contact means that the light emitted from the transparent prism film or sheet directly enters the light scattering layer, and means that, for example, an air layer or the like is not provided in the middle. This is preferable because light reflection is reduced and there is no light loss. As a method of optically adhering the light diffusion layer to the surface of the transparent prism film or sheet, a known method such as a hot pressing method or a coextrusion method can be used.
【００１５】本発明においては透明プリズムフィルムま
たはシートの屈折率と光拡散層の屈折率とをほぼ同一に
するとよい。このように屈折率をほぼ同一にすると、光
が境界面で反射しなくなるので、光の損失がなく好まし
い。屈折率をほぼ同一にする方法としては種々あるが、
同じ材料で製造することが最も好ましい。例えば、透明
プリズムフィルムまたはシートをポリカーボネートで製
造すると、この透明プリズムフィルムまたはシートの表
面にポリカーボネートと光拡散物質との組成物からなる
光拡散層を設けるのである。In the present invention, it is preferable that the refractive index of the transparent prism film or sheet and the refractive index of the light diffusion layer are substantially the same. When the refractive indices are substantially the same as described above, light is not reflected on the boundary surface, which is preferable because there is no light loss. There are various methods to make the refractive indices almost the same,
Most preferably it is made of the same material. For example, when a transparent prism film or sheet is manufactured from polycarbonate, a light diffusing layer made of a composition of polycarbonate and a light diffusing substance is provided on the surface of the transparent prism film or sheet.
【００１６】本発明に使用する透明プリズムまたはシー
トの平らな傾斜面の角度は、導光板の厚み、透明プリズ
ムフィルムまたはシートの屈折率、使用する人が見る方
向、即ち、面光源装置からの好ましい出光角度等によっ
て異なる。本発明においてはこの透明プリズムフィルム
またはシートを導光板に、凹凸条の面を導光板に当接さ
せて設けているが、この透明プリズムフィルムまたはシ
ートの凹凸条の方向は、線状の光源に直角でない任意の
方向でよい。しかし、凹凸条が線状の光源にほぼ平行な
方向が好ましい。The angle of the flat inclined surface of the transparent prism or sheet used in the present invention is preferably the thickness of the light guide plate, the refractive index of the transparent prism film or sheet, the direction seen by the user, that is, the surface light source device. It depends on the light output angle. In the present invention, the transparent prism film or sheet is provided on the light guide plate, and the surface of the uneven strip is provided in contact with the light guide plate. It may be any direction other than a right angle. However, it is preferable that the uneven lines are substantially parallel to the linear light source.
【００１７】[0017]
【作用】本発明面光源装置では、導光板の端面に線状の
光源が設けられているから、この光源から放射された光
は端面から導光板の中に入る。そして、この光は導光板
の裏面に施されている乱反射層により乱反射され、直接
表面に出るか、この導光板の裏面に設けられている反射
板で反射されて表面に出る。この導光板から出た光は図
４に示すように極めて方向性が強い。In the surface light source device of the present invention, since the linear light source is provided on the end surface of the light guide plate, the light emitted from this light source enters the light guide plate from the end surface. Then, this light is diffusely reflected by the diffuse reflection layer provided on the back surface of the light guide plate and directly appears on the front surface, or is reflected by a reflection plate provided on the back surface of the light guide plate and appears on the front surface. The light emitted from this light guide plate is extremely directional as shown in FIG.
【００１８】この導光板の表面には、傾斜面からなる凹
凸条が設けられている透明プリズムフィルムまたはシー
トが凹凸条の面を導光板に当接させて設けられているか
ら、導光板から出た方向性の強い光は、この傾斜面で変
えられて、透明プリズムフィルムまたはシートの中に入
り、この透明プリズムフィルムまたはシートの中を通っ
て表面から使用者が見る方向に出光する。On the surface of this light guide plate, there is provided a transparent prism film or sheet provided with an uneven surface made of inclined surfaces with the surface of the uneven surface in contact with the light guide plate. The highly directional light is changed by this inclined surface, enters the transparent prism film or sheet, and passes through the transparent prism film or sheet and is emitted from the surface in the direction viewed by the user.
【００１９】この透明プリズムフィルムまたはシートか
ら出た光は乱反射層が見える状態にあるが、本発明にお
いては、更に、この透明プリズムフィルムまたはシート
の上に光拡散層が設けられているから、透明プリズムフ
ィルムまたはシートから出た光はこの光拡散層の中に入
り、この光拡散層の中で拡散されて、反射板の乱反射層
が消えて、見やすい光となって、光拡散層から出光す
る。The light emitted from this transparent prism film or sheet is in a state in which the irregular reflection layer is visible, but in the present invention, since a light diffusion layer is further provided on this transparent prism film or sheet, it is transparent. The light emitted from the prism film or sheet enters the light diffusion layer, is diffused in the light diffusion layer, the irregular reflection layer of the reflector disappears, becomes light that is easy to see, and emerges from the light diffusion layer. .
【００２０】本発明において、導光板の表面に透明プリ
ズムフィルムまたはシートの凹凸条を、線状の光源にほ
ぼ平行にし、この凹凸条を当接させて設けると、光が透
明プリズルフィルムまたはシートの凹凸条にほぼ直角に
差し込むので、透明プリズムフィルムまたはシートの中
に光が効率よく入り、光の損失が少なくなる。又、本発
明において、透明プリズムフィルムまたはシートの凹凸
条の面に光拡散層を光学的に密着させたり、透明プリズ
ムフィルムまたはシートの屈折率をほぼ同じにすると、
光が透明プリズムフィルムまたはシートから光拡散層に
入るとき、光の損失がなくなり、効率よく出光させるこ
とができる。In the present invention, when the unevenness of the transparent prism film or sheet is provided on the surface of the light guide plate substantially parallel to the linear light source and the unevenness is brought into contact with the unevenness, the light is transparent. Since it is inserted almost at right angles into the concave-convex strips, the light efficiently enters the transparent prism film or sheet, and the light loss is reduced. Further, in the present invention, when the light diffusing layer is brought into optical contact with the surface of the concave-convex stripes of the transparent prism film or sheet, or the refractive index of the transparent prism film or sheet is made substantially the same,
When light enters the light diffusion layer from the transparent prism film or sheet, there is no loss of light, and light can be efficiently emitted.
【００２１】[0021]
【実施例】次に、本発明の実施例を説明する。図１〜３
は本発明面光源装置の一実施例を示すもので、図１は本
発明面光源装置の主要部を示す断面図、図２は光解散層
の位置によって出光した光がいかに変わるかを比較する
ために試験した比較例の面光源装置の主要部を示す断面
図、図３は図１に示した面光源装置の配光特性と図２に
示した面光源装置の配光特性とを示した配光特性図であ
る。EXAMPLES Next, examples of the present invention will be described. Figures 1-3
1 shows an embodiment of the surface light source device of the present invention. FIG. 1 is a cross-sectional view showing the main part of the surface light source device of the present invention, and FIG. 2 compares how the light emitted changes depending on the position of the light dissipating layer. A cross-sectional view showing a main part of a surface light source device of a comparative example tested for this purpose, and FIG. 3 shows a light distribution characteristic of the surface light source device shown in FIG. 1 and a light distribution characteristic of the surface light source device shown in FIG. It is a light distribution characteristic diagram.
【００２２】図１において、１は厚み３ｍｍのポリメチ
ルメタクリル板からなる導光板であり、この導光板１の
裏面にはドットがスクリーン印刷が施され乱反射層が設
けられている。２は反射板であり、導光板１の裏面に設
けられていて、この導光板１の裏面に出光した光を反射
させて再び導光板１に戻すものである。５は導光板１の
端面に設けられた蛍光灯からなる線状の光源である。In FIG. 1, reference numeral 1 is a light guide plate made of a polymethylmethacrylate plate having a thickness of 3 mm, and dots are screen-printed on the back surface of the light guide plate 1 to provide an irregular reflection layer. Reference numeral 2 denotes a reflection plate, which is provided on the back surface of the light guide plate 1 and reflects the light emitted to the back surface of the light guide plate 1 and returns it to the light guide plate 1 again. Reference numeral 5 is a linear light source provided on the end surface of the light guide plate 1 and made of a fluorescent lamp.
【００２３】３は透明プリズムシートであり、この透明
プリズムシート３はポリカーボネート板の一面に傾斜面
からなる凹凸条が設けられたものである。この傾斜面の
角度は、光源に近い側が７０°であり、反対側が５５°
である。これを図１で示すと、図１のａが７０°であ
り、ｂが５５°である。４は光拡散層であり、ポリカー
ボネート１００重量部に対して酸化チタン粉末２０重量
部を均一に混合し、これを厚み１００μｍのシートに製
造したものである。Reference numeral 3 is a transparent prism sheet, and this transparent prism sheet 3 is a polycarbonate plate provided with an uneven line formed of an inclined surface on one surface. The angle of this inclined surface is 70 ° on the side closer to the light source and 55 ° on the opposite side.
Is. This is shown in FIG. 1. In FIG. 1, a is 70 ° and b is 55 °. Reference numeral 4 denotes a light diffusion layer, which is prepared by uniformly mixing 20 parts by weight of titanium oxide powder with 100 parts by weight of polycarbonate and manufacturing a sheet having a thickness of 100 μm.
【００２４】この透明プリズムシート３と光拡散層４と
は共押出法で同時に押し出して一体に成形されている。
従って、透明プリズムシート３と光拡散層４とは光学的
に密着している。この実施例では透明プリズムシート３
と光拡散層４とが一体になったものを凹凸条が線状の光
源５にほぼ平行になるようにして凹凸条の面を導光板１
に当接させて、導光板１の表面に設けている。６は反射
カバーであり、この反射カバー６は光源５の背後に取り
付けられ、光源５から放射された光を導光板１に端面か
ら効率よく入光させるものである。The transparent prism sheet 3 and the light diffusing layer 4 are extruded at the same time by a coextrusion method to be integrally molded.
Therefore, the transparent prism sheet 3 and the light diffusion layer 4 are in optical contact with each other. In this embodiment, the transparent prism sheet 3
The light-diffusing layer 4 and the light-diffusing layer 4 are integrated so that the uneven line is substantially parallel to the linear light source 5.
And is provided on the surface of the light guide plate 1. Reference numeral 6 denotes a reflection cover, which is attached to the back of the light source 5 and allows the light emitted from the light source 5 to efficiently enter the light guide plate 1 from the end surface.
【００２５】次に、この図１に示す面光源装置の使用方
法について説明する。光源５を点灯する。すると、この
光源５から放射された光は直接または反射カバー６で反
射されて、導光板１の中に入る。この導光板１に入った
光は裏面に設けられた乱反射層の面で乱反射され、直接
または反射板２で反射されて、導光板１の表面から図４
に示すように指向性（導光板との角度が約２０°）の強
い光が出る。Next, a method of using the surface light source device shown in FIG. 1 will be described. The light source 5 is turned on. Then, the light emitted from the light source 5 enters the light guide plate 1 directly or is reflected by the reflection cover 6. The light that has entered the light guide plate 1 is diffusely reflected by the surface of the diffuse reflection layer provided on the back surface and is reflected directly or by the reflection plate 2 from the surface of the light guide plate 1 as shown in FIG.
As shown in, light with a strong directivity (the angle with the light guide plate is about 20 °) is emitted.
【００２６】この表面から出た光は透明プリズムシート
３の傾斜面によって角度が変えられて（導光板との角度
が約９０°）、透明プリズムシート３の中に入る。この
光はプリズムシート３の中を通って透明プリズムシート
３の表面から光拡散層４に入る。この際、透明プリズム
シート３と光拡散層４とは、共押出法によって一体に成
形され（光学的に密着され）、且つ両者の材料が同一
（屈折率が同一）であるから、プリズムシート３から光
拡散層４に入るときの光の損失は殆どなかった。この光
拡散層４の中で光が拡散されて、光拡散層４の表面から
出光する。The angle of the light emitted from this surface is changed by the inclined surface of the transparent prism sheet 3 (the angle with the light guide plate is about 90 °) and enters the transparent prism sheet 3. This light passes through the prism sheet 3 and enters the light diffusion layer 4 from the surface of the transparent prism sheet 3. At this time, the transparent prism sheet 3 and the light diffusing layer 4 are integrally molded (optically adhered) by a co-extrusion method, and the materials of both are the same (the refractive index is the same). There was almost no loss of light when entering the light diffusion layer 4. Light is diffused in the light diffusion layer 4 and emitted from the surface of the light diffusion layer 4.
【００２７】透明プリズムシート３を覗いたところ乱反
射層が見えなかった。又、この光を表示装置に当てる
と、表示装置が極めて見易かった。又、この出光された
光の配光特性を測定したところ、図３のｄに示すように
なった。When the transparent prism sheet 3 was looked into, the irregular reflection layer was not visible. When this light was applied to the display device, the display device was extremely easy to see. Further, when the light distribution characteristics of the emitted light were measured, it was as shown in FIG. 3d.
【００２８】次に、この図１に示す実施例の光拡散層を
設ける位置を比較するために比較試験を行った。この比
較例を図２を参照しながら説明する。この比較例では、
光拡散層４ａを導光板１ａの表面に直接設け、この光拡
散層４ａの上に透明プリズムシート３ａを設けたもので
ある。その他は図１に示す実施例と同じ構造である。Next, a comparative test was conducted to compare the positions where the light diffusion layers of the embodiment shown in FIG. 1 were provided. This comparative example will be described with reference to FIG. In this comparative example,
The light diffusion layer 4a is directly provided on the surface of the light guide plate 1a, and the transparent prism sheet 3a is provided on the light diffusion layer 4a. The other structure is the same as that of the embodiment shown in FIG.
【００２９】この図２に示す比較例の配光特性を図１に
示す実施例と同じ方法で測定したところ、図３のｅに示
すようになった。実施例と比較例の配光特性を比較する
と、実施例の光が比較例より強いことが判る。即ち、光
が効率よく出光されていることが判る。この図３に示す
配光特性から判るように、本実施例の面光源装置は望ま
しい方向に光が向き、しかも、光の輝度が大きく、乱反
射層が見えなく、理想的な面光源装置である。The light distribution characteristics of the comparative example shown in FIG. 2 were measured by the same method as that of the embodiment shown in FIG. 1, and the result was as shown by e in FIG. Comparing the light distribution characteristics of the example and the comparative example, it can be seen that the light of the example is stronger than that of the comparative example. That is, it can be seen that the light is efficiently emitted. As can be seen from the light distribution characteristics shown in FIG. 3, the surface light source device of this embodiment is an ideal surface light source device in which the light is directed in a desired direction, the brightness of the light is large, and the irregular reflection layer is not visible. .
【００３０】[0030]
【発明の効果】本発明面光源装置は光拡散層が透明プリ
ズムフィルムまたはシートの表面、即ち、透明プリズム
フィルムまたはシートの凹凸条の反対側の面に設けられ
ているから、透明プリズムまたはシートから出光した乱
反射層が見える光が、光拡散層で拡散され、乱反射層が
消えて、見易い光となって出光する。従って、この光を
液晶が用いられている表示装置に照射すると見易い画面
となり、価値あるものである。According to the surface light source device of the present invention, since the light diffusion layer is provided on the surface of the transparent prism film or sheet, that is, the surface of the transparent prism film or sheet on the side opposite to the concave and convex stripes, the transparent prism or sheet is used. The light from which the diffuse reflection layer that has emerged is visible is diffused by the light diffusion layer, the diffuse reflection layer disappears, and becomes light that is easy to see and emerges. Therefore, when the display device using liquid crystal is irradiated with this light, the screen becomes easy to see, which is valuable.
【００３１】又、導光板の表面に透明プリズムフィルム
またはシートの凹凸条を線状の光源にほぼ平行にし、透
明プリズムフィルムまたはシートの凹凸条を当接させて
設けると、光が透明プリズムフィルムまたはシートの中
に効率よく入るので、光の損失が少なくなる。If the unevenness of the transparent prism film or sheet is made substantially parallel to the linear light source on the surface of the light guide plate and the unevenness of the transparent prism film or sheet is brought into contact with the light source, the light is transmitted through the transparent prism film or Efficient entry into the sheet reduces light loss.
【００３２】又、透明プリズムフィルムまたはシートの
凹凸条の面に光拡散層を光学的に密着させたり、透明プ
リズムフィルムまたはシートの屈折率と光拡散層の屈折
率をほぼ同じにすると、光の損失が少なくなり、効率よ
く出光させることができる。このように、光の損失を少
なくする工夫をすることにより、光の輝度を更に向上さ
せることができ、価値あるものとなる。Further, if the light diffusing layer is optically closely adhered to the surface of the uneven prism of the transparent prism film or sheet, or if the refractive index of the transparent prism film or sheet and the refractive index of the light diffusing layer are substantially the same, Loss is reduced and light can be emitted efficiently. In this way, by devising a method for reducing the loss of light, the brightness of light can be further improved, which is valuable.
【図１】図１は本発明面光源装置の一実施例を示すもの
で、面光源装置の主要部を示す断面図である。FIG. 1 shows an embodiment of a surface light source device of the present invention, and is a cross-sectional view showing a main part of the surface light source device.
【図２】図２は光拡散層の位置によって、出光した光が
いかに変わるかを比較するために試験したの比較例の面
光源装置の主要部を示す断面図である。FIG. 2 is a cross-sectional view showing a main part of a surface light source device of a comparative example, which was tested in order to compare how the emitted light changes depending on the position of the light diffusion layer.
【図３】図３は図１に示した面光源装置の配光特性と図
２に示した面光源装置の配光特性とを示した配光特性図
である。FIG. 3 is a light distribution characteristic diagram showing a light distribution characteristic of the surface light source device shown in FIG. 1 and a light distribution characteristic of the surface light source device shown in FIG.
【図４】図４は従来の面光源装置の配光特性を示す説明
図である。FIG. 4 is an explanatory diagram showing a light distribution characteristic of a conventional surface light source device.
【図５】図５は従来の面光源装置の配光特性を示す説明
図である。FIG. 5 is an explanatory diagram showing a light distribution characteristic of a conventional surface light source device.
１、１ａ 導光板 ２ 反射板 ３、３ａ 透明プリズムフィルムまた
はシート ４、４ａ 光拡散層 ５ 光源 ６ 反射カバー1, 1a Light guide plate 2 Reflector plate 3 and 3a Transparent prism film or sheet 4, 4a Light diffusion layer 5 Light source 6 Reflective cover
Claims (4)
の端面に線状の光源が設けられ、この導光板の表面に、
平らな傾斜面からなる凹凸条が設けられている透明プリ
ズムフィルムまたはシートが凹凸条の面を導光板に当接
させて設けられ、この導光板の裏面に反射板が設けられ
ている面光源装置において、透明プリズムフィルムまた
はシートの凹凸条と反対側の面に光拡散層が設けられて
いることを特徴とする面光源装置。1. A linear light source is provided on an end surface of a transparent light guide plate having a back surface provided with an irregular reflection layer, and a linear light source is provided on the surface of the light guide plate.
A surface light source device in which a transparent prism film or sheet provided with an uneven line formed of a flat inclined surface is provided with the surface of the uneven line in contact with a light guide plate, and a reflecting plate is provided on the back surface of the light guide plate. 2. A surface light source device according to claim 1, wherein a light diffusion layer is provided on the surface of the transparent prism film or sheet opposite to the concavo-convex stripes.
凸条を線状の光源にほぼ平行にし、凹凸条の面を導光板
に当接させて導光板の表面に設けられていることを特徴
とする請求項１記載の面光源装置。2. A transparent prism film or sheet is provided on the surface of a light guide plate such that the ridges and ridges are substantially parallel to a linear light source, and the surface of the ridges is in contact with the light guide plate. Item 2. The surface light source device according to item 1.
凸条と反対側の面に光拡散層が、光学的に密着して設け
られていることを特徴とする請求項１記載の面光源装
置。3. The surface light source device according to claim 1, wherein a light diffusion layer is provided in optical contact with the surface of the transparent prism film or sheet on the side opposite to the concavo-convex stripes.
折率と光拡散層の屈折率とがほぼ同一であることを特徴
とする請求項１記載の面光源装置。4. The surface light source device according to claim 1, wherein the refractive index of the transparent prism film or sheet and the refractive index of the light diffusion layer are substantially the same.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4179765A JPH0627325A (en) | 1992-07-07 | 1992-07-07 | Surface light source device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4179765A JPH0627325A (en) | 1992-07-07 | 1992-07-07 | Surface light source device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0627325A true JPH0627325A (en) | 1994-02-04 |
Family
ID=16071498
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4179765A Pending JPH0627325A (en) | 1992-07-07 | 1992-07-07 | Surface light source device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0627325A (en) |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5488545A (en) * | 1993-06-30 | 1996-01-30 | Nippondenso Co., Ltd. | Lighting fixture control apparatus for vehicle |
| WO1997017631A1 (en) * | 1995-11-06 | 1997-05-15 | Seiko Epson Corporation | Illuminator, liquid crystal display using the illuminator and electronic device |
| WO1997029398A1 (en) * | 1996-02-07 | 1997-08-14 | Nitto Jushi Kogyo Kabushiki Kaisha | Surface light source device, liquid crystal display and asymmetric prism sheet |
| US6072551A (en) * | 1996-02-14 | 2000-06-06 | Physical Optics Corporation | Backlight apparatus for illuminating a display with controlled light output characteristics |
| US6130730A (en) * | 1996-02-14 | 2000-10-10 | Physical Optics Corporation | Backlight assembly for a display |
| US6862141B2 (en) | 2002-05-20 | 2005-03-01 | General Electric Company | Optical substrate and method of making |
| US7180672B2 (en) | 2002-05-20 | 2007-02-20 | General Electric Company | Optical substrate and method of making |
| CN1316297C (en) * | 2004-04-30 | 2007-05-16 | 友达光电股份有限公司 | Light conducting plate and manufacturing method thereof |
| US7248412B2 (en) | 2003-12-31 | 2007-07-24 | General Electric Company | Optical substrate with modulated structure |
| US20090199900A1 (en) * | 2008-02-12 | 2009-08-13 | Qualcomm Mems Technologies, Inc. | Thin film holographic solar concentrator/collector |
| US7598939B2 (en) | 2001-10-23 | 2009-10-06 | Nec Corporation | Liquid crystal display device, backlight used for same display device, method for driving same backlight and method for manufacturing same backlight |
| US7859759B2 (en) | 2002-05-20 | 2010-12-28 | Sabic Innovative Plastics Ip B.V. | Film, backlight displays, and methods for making the same |
| JP2013516778A (en) * | 2010-01-08 | 2013-05-13 | サン−ゴバン アドフォル | Light collector |
| JP2020536289A (en) * | 2018-02-28 | 2020-12-10 | エルジー・ケム・リミテッド | Viewing angle compensation film, polarizing plate including it, and display device including it |
-
1992
- 1992-07-07 JP JP4179765A patent/JPH0627325A/en active Pending
Cited By (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5488545A (en) * | 1993-06-30 | 1996-01-30 | Nippondenso Co., Ltd. | Lighting fixture control apparatus for vehicle |
| KR100453398B1 (en) * | 1995-11-06 | 2005-06-20 | 세이코 엡슨 가부시키가이샤 | Lighting devices and liquid crystal displays and electronic devices using them |
| WO1997017631A1 (en) * | 1995-11-06 | 1997-05-15 | Seiko Epson Corporation | Illuminator, liquid crystal display using the illuminator and electronic device |
| US6011602A (en) * | 1995-11-06 | 2000-01-04 | Seiko Epson Corporation | Lighting apparatus with a light guiding body having projections in the shape of a trapezoid |
| WO1997029398A1 (en) * | 1996-02-07 | 1997-08-14 | Nitto Jushi Kogyo Kabushiki Kaisha | Surface light source device, liquid crystal display and asymmetric prism sheet |
| US5914759A (en) * | 1996-02-07 | 1999-06-22 | Nitto Jushi Kogyo Kabushiki Kaisha | Surface light source device, liquid crystal display and asymmetric prism sheet |
| US6072551A (en) * | 1996-02-14 | 2000-06-06 | Physical Optics Corporation | Backlight apparatus for illuminating a display with controlled light output characteristics |
| US6130730A (en) * | 1996-02-14 | 2000-10-10 | Physical Optics Corporation | Backlight assembly for a display |
| US7598939B2 (en) | 2001-10-23 | 2009-10-06 | Nec Corporation | Liquid crystal display device, backlight used for same display device, method for driving same backlight and method for manufacturing same backlight |
| US8599125B2 (en) | 2001-10-23 | 2013-12-03 | Getner Foundation Llc | Liquid crystal display device, backlight used for same display device, method for driving same backlight and method for manufacturing same backlight |
| US9111495B2 (en) | 2001-10-23 | 2015-08-18 | Getner Foundation Llc | Liquid crystal display device, backlight used for same display device, method for driving same backlight and method for manufacturing same backlight |
| US6862141B2 (en) | 2002-05-20 | 2005-03-01 | General Electric Company | Optical substrate and method of making |
| US7324284B2 (en) | 2002-05-20 | 2008-01-29 | General Electric Company | Optical substrate and method of making |
| US7180672B2 (en) | 2002-05-20 | 2007-02-20 | General Electric Company | Optical substrate and method of making |
| US7859759B2 (en) | 2002-05-20 | 2010-12-28 | Sabic Innovative Plastics Ip B.V. | Film, backlight displays, and methods for making the same |
| US7965447B2 (en) | 2002-05-20 | 2011-06-21 | Sabic Innovative Plastics Ip B.V. | Optical substrate and method of making |
| US7483195B2 (en) | 2003-12-31 | 2009-01-27 | Sabic Innovative Plastics Ip B.V. | Optical substrate with modulated structure |
| US7248412B2 (en) | 2003-12-31 | 2007-07-24 | General Electric Company | Optical substrate with modulated structure |
| CN1316297C (en) * | 2004-04-30 | 2007-05-16 | 友达光电股份有限公司 | Light conducting plate and manufacturing method thereof |
| US20090199900A1 (en) * | 2008-02-12 | 2009-08-13 | Qualcomm Mems Technologies, Inc. | Thin film holographic solar concentrator/collector |
| JP2013516778A (en) * | 2010-01-08 | 2013-05-13 | サン−ゴバン アドフォル | Light collector |
| JP2020536289A (en) * | 2018-02-28 | 2020-12-10 | エルジー・ケム・リミテッド | Viewing angle compensation film, polarizing plate including it, and display device including it |
| US11686967B2 (en) | 2018-02-28 | 2023-06-27 | Lg Chem, Ltd. | Viewing angle compensation film, polarizing plate comprising same, and display device comprising same |
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