JPH0682635A - Surface light source device - Google Patents
Surface light source deviceInfo
- Publication number
- JPH0682635A JPH0682635A JP5068164A JP6816493A JPH0682635A JP H0682635 A JPH0682635 A JP H0682635A JP 5068164 A JP5068164 A JP 5068164A JP 6816493 A JP6816493 A JP 6816493A JP H0682635 A JPH0682635 A JP H0682635A
- Authority
- JP
- Japan
- Prior art keywords
- light source
- guide plate
- light
- source device
- sheet
- 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)
- Liquid Crystal (AREA)
- Planar Illumination Modules (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、液晶を用いた表示装置を照射するため
の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。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 for illuminating the display device using the liquid crystal because the liquid crystal itself does not emit light. ing. This backlight needs to be thin and to illuminate the surface of the display device almost uniformly. A surface light source device is usually used for such a backlight.
【０００３】上記液晶を用いた表示装置は、高級化、小
型化の要求がなされ、そのため、面光源装置も表示装置
と同様に、厚みの薄いものが要求される。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。The display device using the above liquid crystal is required to be upscaled and downsized, and therefore, the surface light source device is required to be thin as in the display device. 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.
【０００４】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.
【０００５】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のスクリ
ーン印刷等により乱反射層を設け、導光板の裏面に反射
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ものである。More specifically, in general, 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 is totally reflected 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, a diffuse reflection layer is provided on the back surface of the light guide plate by screen printing of dots such as beads, and a reflection plate is attached to the back surface of the light guide plate to diffusely reflect the light that strikes the back surface of the light guide plate by the diffuse reflection layer, and to perform the diffuse reflection. The reflected light is reflected directly or by a reflection plate and emitted to the outside of the light guide plate.
【０００６】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７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。However, the light emitted from the light source provided on the end surface of the light guide plate normally emerges 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.
【０００７】このことを図７を参照しながら、更に詳細
に説明すると、図７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１０１
の裏面に設けられた乱反射層で乱反射され、導光板１０
１から直接出るか、反射板１０２に反射されて導光板１
０１の表面から出る。そのときのＡ点の光は図７のＢの
ように、導光板１０１との角度が小さい極めて方向性の
強い光である。This will be described in more detail with reference to FIG. 7. In FIG. 7, 101 is a transparent light guide plate having dots printed 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 guide plate 101, and the light emitted from the light source 103 passes through the light guide plate 101 and passes through the light guide plate 101.
Diffusely reflected by the irregular reflection layer provided on the back surface of the light guide plate 10
1 or the light guide plate 1 is reflected by the reflection plate 102.
It goes out from the surface of 01. The light at the point A at that time is light with a very strong directivity, which has a small angle with the light guide plate 101, as shown in FIG. 7B.
【０００８】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８に示すように、導光板１０１の表面
に拡散板１０４を設けると、図８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. 8 to improve this directionality, the directivity becomes gentle as shown in C of FIG. 8, but it is still insufficient. Is.
【０００９】かかる欠点を改良するものとして、特開昭
６２−１４４１０２号公報に記載あるように、片面に直
角二等辺三角形プリズムが規則的に多数並んだ構造面を
有し、その反対側の面が滑らかな平面であるような透明
高分子材料からなるフィルムを、フィルムの平面側を導
光板に向けて導光板に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、指向性の強い光がフィル
ムから出光する際に、光の出光する角度を、直角二等辺
三角形プリズムの表面によって使用者が見る方向に変え
るものである。As a means for improving such a drawback, as described in JP-A-62-144102, a structure surface in which a large number of right-angled isosceles triangular prisms are regularly arranged on one surface and the surface on the opposite side is provided. There is known a surface light source device in which a film made of a transparent polymer material having a smooth surface is provided on the light guide plate with the flat surface side of the film facing the light guide plate. That is, this surface light source device changes the angle at which the light is emitted to the direction viewed by the user by the surface of the isosceles right triangle prism when the light with strong directivity is emitted from the film.
【００１０】又、特開平２−１７号公報に記載あるよう
に、導光板の表面に、平らな傾斜面からなる凹凸条を規
則的に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
またはシートの表面から出光させるものである。Further, as described in Japanese Patent Application Laid-Open No. 2-17, a transparent prism film or sheet in which irregularities made of flat inclined surfaces are regularly provided on the surface of a light guide plate is used. A surface light source device provided in contact with a light guide plate is known. That is, this surface light source device changes the light having a strong directivity in the direction in which the user sees it by the flat inclined surface of the concavo-convex strip of the transparent prism film or sheet, and emits the light from the surface of the transparent prism film or sheet.
【００１１】[0011]
【発明が解決しようとする課題】しかしながら、特開昭
６２−１４４１０２号公報に記載の面光源装置及び特開
平２−１７号公報に記載の面光源装置は、透明プリズム
フィルムまたはシートを通過する光に、凹凸条に対応し
た明暗が発生し、この上に液晶を用いた表示装置を設け
ると、この明暗に起因するモアレ干渉縞が発生し易く、
表示装置としては好ましくなかった。However, the surface light source device described in Japanese Patent Laid-Open No. 62-144102 and the surface light source device described in Japanese Patent Laid-Open No. 2-17 are disclosed in Japanese Patent Application Laid-Open No. 62-144102. In addition, bright and dark corresponding to the uneven strips are generated, and when a display device using liquid crystal is provided on this, moire interference fringes due to the bright and dark are easily generated,
It was not preferable as a display device.
【００１２】本発明の目的は、使用者が見る方向に高い
輝度を保ち、しかも、透明プリズムフィルムまたはシー
トの規則的な凹凸条から生じる明暗に起因するモアレ干
渉縞が発生が発生しない面光源装置を提供することであ
る。An object of the present invention is to provide a surface light source device which maintains a high brightness in the viewing direction of a user and does not cause moire interference fringes due to light and dark generated from regular uneven lines of a transparent prism film or sheet. Is to provide.
【００１３】[0013]
【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のピッチが不規則に配置されてい
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 surface light source device in which a light source is provided, a transparent prism film or sheet in which uneven surfaces made of flat inclined surfaces are provided on the surface of the light guide plate, and a reflecting plate is provided on the back surface of the light guide plate In the above, the pitch of the uneven strips of the transparent prism film or sheet is arranged irregularly.
【００１４】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
メタクリレート、ポリエステル等の透明な樹脂を表面を
凹凸条を設けながら押し出して成形する方法である。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 by providing an uneven 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. A preferred 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, polyester, etc. is extruded while the surface is provided with uneven lines.
【００１５】本発明に使用する透明プリズムフィルムま
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、凹凸条を線状の光源
にほぼ平行になるように設けることが好ましい。The angle of the flat inclined surface of the transparent prism film or sheet used in the present invention depends on the thickness of the light guide plate, the refractive index of the transparent prism film or sheet, the direction viewed by the user, that is, from the surface light source device. It depends on a preferable light emitting angle and the like. In the present invention, the direction of the uneven strips of the transparent prism film or sheet may be any direction that is not perpendicular to the linear light source. However, it is preferable to provide the uneven lines so as to be substantially parallel to the linear light source.
【００１６】又、この凹凸条のピッチは不規則な任意な
ピッチでよいが、２０μｍから５００μｍの間で不規則
に配置したものが好ましい。又、この凹凸条の山部と谷
部の稜部をそれぞれ曲面にすると、光が適宜拡散して好
ましい。The pitch of the irregular stripes may be any irregular pitch, but it is preferable that the pitch is irregularly arranged between 20 μm and 500 μm. Further, it is preferable that the peaks and the ridges of the valleys of the uneven line are curved so that the light is appropriately diffused.
【００１７】尚、透明プリズムフィルムまたはシートの
凹凸条を導光板に当接して用いると、凹凸状と反対側の
面を導光板に当接して用いる場合よりも、光量損失が少
なくて好ましい。It is preferable to use the concavo-convex stripes of the transparent prism film or sheet in contact with the light guide plate, because the light quantity loss is smaller than in the case where the surface opposite to the concavo-convex shape is used in contact with the light guide plate.
【００１８】又、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も凹凸条を設けた方が光が適宜拡
散して好ましい。又、透明プリズムフィルムまたはシー
トの凹凸条のピッチを不規則にすると同時に、凹凸条の
傾斜面の傾斜角度を不規則にすると、モアレ干渉縞が発
生せず好ましい。Further, it is preferable that the surface of the transparent prism film or sheet opposite to the concavo-convex line is provided with a concavo-convex line so that light is appropriately diffused. Further, it is preferable that the pitch of the uneven strips of the transparent prism film or sheet is irregular and the inclination angle of the inclined surface of the irregular strips is also irregular so that moire interference fringes do not occur.
【００１９】[0019]
【作用】本発明の面光源装置では、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、この導光板に
入った光は導光板の裏面に設けられた乱反射層で乱反射
され、直接表面から出るか、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７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, the light entering the light guide plate is diffusely reflected by the diffuse reflection layer provided on the back surface of the light guide plate and directly exits from the front surface, or is reflected by the reflector plate provided on the back surface of the light guide plate and goes out to the front surface. The light emitted from this light guide plate has extremely strong directivity as shown in FIG.
【００２０】この導光板の表面には、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、この平らな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表面から使用者が見る方向に
出光する。Since the surface of the light guide plate is provided with the transparent prism film or sheet provided with the uneven strips formed of the flat inclined surface, the light having strong directionality emitted from the light guide plate is flattened. The light is emitted in the direction viewed by the user from the surface of the transparent prism film or sheet after being changed by a different inclined surface.
【００２１】従来のように凹凸条が規則的であり、凹凸
条が導光板に当接していれば、透明プリズムフィルムま
たはシートから出た光は、凹凸条に対応した明暗が発生
し、この上に液晶を用いた表示装置を設けると、この明
暗に起因するモアレ干渉縞が発生し易いが、本発明で
は、凹凸条ピッチが不規則に配置されているから、モア
レ干渉縞が発生することがないので、見易い画面とな
る。If the ridges are regular as in the prior art, and the ridges are in contact with the light guide plate, the light emitted from the transparent prism film or sheet will produce light and dark corresponding to the ridges. When a display device using liquid crystal is provided in the above, moire interference fringes due to the light and shade are likely to occur. However, in the present invention, since the uneven pitches are arranged irregularly, the moire interference fringes may occur. Since it does not exist, the screen is easy to see.
【００２２】又、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が導光板に当接していても、モアレ
干渉縞が発生することがないので、見易い画面となる。Even if the surface of the transparent prism film or sheet on the side opposite to the concave-convex stripes is in contact with the light guide plate, moire interference fringes do not occur, so that the screen is easy to see.
【００２３】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が、凹凸条を線状の光源にほ
ぼ平行にすると、光が透明プリズム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、出光する光の角
度を大きくできる。In the present invention, when the transparent prism film or sheet is provided on the surface of the light guide plate so that the uneven line is substantially parallel to the linear light source, light is injected into the uneven line of the transparent prism film or sheet at a substantially right angle. The angle of light can be increased.
【００２４】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ピッチが２０μｍから５００μｍ
の間に不規則に配置されていると、この面光源装置から
出た光を表示装置に照射したとき凹凸条による明暗が気
にならない見易い画面となる。In the present invention, the pitch of the uneven stripes of the transparent prism film or sheet is 20 μm to 500 μm.
If the light emitted from the surface light source device is applied to the display device, the screen is easy to see without being bothered by the light and darkness due to the uneven strips.
【００２５】本発明において、凹凸条の山部と谷部の稜
部それぞれ曲面にすると、光が適宜拡散し好ましい。In the present invention, it is preferable that the peaks and the ridges of the valleys of the concave and convex lines have curved surfaces so that light is appropriately diffused.
【００２６】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と反対側の面にも凹凸条を設ける
と、両方の明暗が入り混ざり、明暗がハッキリしなくな
り、この面光源装置の前に液晶を使用した表示装置を置
くと、表示装置が見易い画面となる。In the present invention, if the surface of the transparent prism film or sheet opposite to the concavo-convex stripes is also provided with concavo-convex stripes, both light and dark are mixed and the light and dark are not clearly defined. When the used display device is placed, the display device has a screen that is easy to see.
【００２７】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ピッチを不規則にすると同時に、
凹凸条の傾斜面の傾斜角度を不規則にすると、モアレ干
渉縞が更に発生し難くなるので好ましい。In the present invention, the pitch of the uneven strips of the transparent prism film or sheet is made irregular, and at the same time,
It is preferable to make the inclination angle of the inclined surface of the uneven liner irregular, because it becomes more difficult to generate moire interference fringes.
【００２８】[0028]
【実施例】次に、本発明の実施例を説明する。図１は本
発明の第１の実施例を示すもので、面光源装置の断面図
である。図２は本発明の第２の実施例を示すもので、面
光源装置の断面図である。図３は本発明の第３の実施例
を示すもので、面光源装置の断面図である。図４は本発
明の第４の実施例を示すもので、面光源装置の断面図で
ある。図５は本発明の面光源装置の効果を比較するため
に試験した比較例の面光源装置の断面図である。図６は
本発明の面光源装置の効果を比較するために試験した比
較例の面光源装置の断面図である。EXAMPLES Next, examples of the present invention will be described. 1 shows a first embodiment of the present invention and is a sectional view of a surface light source device. FIG. 2 shows a second embodiment of the present invention and is a sectional view of a surface light source device. FIG. 3 shows a third embodiment of the present invention and is a sectional view of a surface light source device. FIG. 4 shows a fourth embodiment of the present invention and is a sectional view of a surface light source device. FIG. 5 is a cross-sectional view of a surface light source device of a comparative example that was tested in order to compare the effects of the surface light source device of the present invention. FIG. 6 is a cross-sectional view of a surface light source device of a comparative example that was tested in order to compare the effects of the surface light source device of the present invention.
【００２９】図１及び図２において、１は厚み３ｍｍの
ポリメチルメタクリレートからなる導光板であり、この
導光板１の裏面にはドット印刷された乱反射層が設けら
れている。尚、このドットは円形で、その直径は０．５
ｍｍ〜１．５ｍｍである。２は反射板であり、この反射
板２は導光板１の裏面に設けられて、導光板１の裏面に
出光した光を反射させて、導光板１に戻すものである。
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の薄板の一面に平らな傾斜面か
らなる凹凸条が設けられたものである。この傾斜面の頂
角の角度は、９０°であり、凹凸条のピッチは１００μ
ｍ〜３００μｍの間で不規則になるように配置されてい
る。In FIGS. 1 and 2, reference numeral 1 denotes a light guide plate made of polymethylmethacrylate having a thickness of 3 mm, and a dot reflection irregular reflection layer is provided on the back surface of the light guide plate 1. This dot is circular and its diameter is 0.5.
mm to 1.5 mm. Reference numeral 2 denotes a reflection plate, which is provided on the back surface of the light guide plate 1 to reflect the light emitted to the back surface of the light guide plate 1 and return it to the light guide plate 1.
Reference numeral 3 is a transparent prism sheet, and this transparent prism sheet 3 is a thin sheet of polycarbonate provided with an uneven line formed of a flat inclined surface. The apex angle of this inclined surface is 90 °, and the pitch of the uneven lines is 100 μ.
It is arranged so as to be irregular between m and 300 μm.
【００３０】５は導光板１の端面に設けられた線状の光
源である。６は反射板であり、この反射板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に効率よく入射させるものである。図１においては透
明プリズムシート３は、凹凸条を導光板１に当接し、図
２においては凹凸条の反対側の面を導光板１に当接して
設けてある。Reference numeral 5 is a linear light source provided on the end face of the light guide plate 1. Reference numeral 6 denotes a reflector, which is attached to the back of the light source 5 so that the light emitted from the light source 5 is efficiently incident on the light guide plate 1. In FIG. 1, the transparent prism sheet 3 is provided such that the ridges and valleys are in contact with the light guide plate 1 and the surface on the opposite side of the ridges and grooves is in contact with the light guide plate 1 in FIG.
【００３１】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板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
直接または反射板２で反射されて、表面から図６に示す
ように指向性（導光板１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 by being reflected by the reflecting plate 6. The light that has entered the light guide plate 1 is reflected directly or by the reflection plate 2, and a strong directional light (the angle with the light guide plate 1 is about 20 °) is emitted from the surface as shown in FIG.
【００３２】この表面から出た光は透明プリズムシート
３の両面の凹凸条の傾斜面によって角度が変えられて
（導光板１との角度が約９０°）、透明プリズムフィル
ム３の中に入る。この光は透明プリズムフィルム３の中
を通って、透明プリズムフィルム３の表面から出る。The light emitted from this surface enters the transparent prism film 3 with its angle changed by the inclined surfaces of the uneven strips on both sides of the transparent prism sheet 3 (the angle with the light guide plate 1 is about 90 °). This light passes through the transparent prism film 3 and exits from the surface of the transparent prism film 3.
【００３３】この透明プリズムシート３から出た光は、
透明プリズムシート３の凹凸条のピッチが不規則である
から、凹凸条に起因する明暗のピッチも不規則になって
いた。このようにして面光源装置から出る明暗のピッチ
が不規則になっている光を液晶を用いた表示装置に照射
したところ、モアレ干渉縞が発生せず極めて見易い画面
となった。The light emitted from the transparent prism sheet 3 is
Since the pitch of the uneven strips of the transparent prism sheet 3 is irregular, the pitch of light and dark due to the uneven strips was also irregular. In this way, when the display device using liquid crystal was irradiated with the light with irregular pitches of light and dark emitted from the surface light source device, a moire interference fringe did not occur and the screen was extremely easy to see.
【００３４】図２に示す実施例においては、導光板１の
表面から出た光は透明プリズムシート３の中を通って、
表面の凹凸条の傾斜面によって角度が変えられて（導光
板１との角度が約９０°）、透明プリズムフィルム３の
透明プリズムフィルム３の表面から出る。In the embodiment shown in FIG. 2, the light emitted from the surface of the light guide plate 1 passes through the transparent prism sheet 3,
The angle is changed (the angle with the light guide plate 1 is about 90 °) by the inclined surface of the uneven strip on the surface, and the transparent prism film 3 emerges from the surface of the transparent prism film 3.
【００３５】この透明プリズムシート３から出た光も、
透明プリズムシート３の凹凸条のピッチが不規則である
から、凹凸条に起因する明暗のピッチも不規則になって
いた。このようにして面光源装置から出る明暗のピッチ
が不規則になっている光を液晶を用いた表示装置に照射
したところ、モアレ干渉縞が発生せず極めて見易い画面
となった。The light emitted from the transparent prism sheet 3 is also
Since the pitch of the uneven strips of the transparent prism sheet 3 is irregular, the pitch of light and dark due to the uneven strips was also irregular. In this way, when the display device using liquid crystal was irradiated with the light with irregular pitches of light and dark emitted from the surface light source device, a moire interference fringe did not occur and the screen was extremely easy to see.
【００３６】次に、図３及び図４に示す実施例について
説明する。この図３及び図４に示す実施例では、透明プ
リズムシート３ａがポリメチルメタクリレートの薄板で
あること、透明プリズムシート３ａの凹凸条の傾斜面の
頂角が７０°〜１１０°の間で適宜不規則に配置されて
いること、凹凸条のピッチが７０μｍ〜２５０μｍの間
で適宜不規則に配置されていることが異なる。その他は
図１及び図２に示す実施例とそれぞれ同じ構造をしてい
る。この図３及び図４に示す実施例でも、モアレ干渉縞
が発生せず、光が適宜拡散され極めて見易い画面となっ
た。Next, the embodiment shown in FIGS. 3 and 4 will be described. In the embodiment shown in FIGS. 3 and 4, the transparent prism sheet 3a is a thin plate of polymethylmethacrylate, and the apex angle of the inclined surface of the concave-convex stripes of the transparent prism sheet 3a is not properly set between 70 ° and 110 °. The difference is that they are arranged regularly and irregular pitches are appropriately arranged between 70 μm and 250 μm. Others have the same structure as the embodiment shown in FIGS. 1 and 2. Also in the examples shown in FIGS. 3 and 4, moire interference fringes did not occur, and light was appropriately diffused to provide an extremely easy-to-see screen.
【００３７】次に図５及び図６に示す比較例を説明す
る。この図５及び図６に示す比較例では、透明プリズム
シート３ｂの傾斜面からなる凹凸条の傾斜面の頂角が９
０°であり、規則正しいピッチで配置されていることが
図１及び図２に示す実施例と異なる。その他は図１及び
図２に示す実施例と同じである。この図５及び図６に示
す比較例の面光源装置の前に液晶が用いられた表示装置
を置くと、表示装置にモアレ干渉縞が多数見えて、見難
い画面となった。Next, a comparative example shown in FIGS. 5 and 6 will be described. In the comparative example shown in FIGS. 5 and 6, the apex angle of the sloped surface of the sloped surface of the transparent prism sheet 3b is 9 degrees.
It is 0 °, which is different from the embodiment shown in FIGS. 1 and 2 in that they are arranged at a regular pitch. Others are the same as those of the embodiment shown in FIGS. When a display device using liquid crystal was placed in front of the surface light source device of the comparative example shown in FIGS. 5 and 6, a large number of moire interference fringes were seen on the display device and the screen was difficult to see.
【００３８】このように、本発明の面光源装置は凹凸条
のピッチが不規則になっているから、この面光源装置の
前に液晶を用いる表示装置を置くと、この表示装置にモ
アレ干渉縞が発生せず、光が適宜拡散して、見易い画面
が得られる。As described above, in the surface light source device of the present invention, the pitch of the uneven lines is irregular. Therefore, if a display device using liquid crystal is placed in front of this surface light source device, moire interference fringes are present in this display device. Does not occur, light is appropriately diffused, and an easy-to-see screen is obtained.
【００３９】[0039]
【発明の効果】本発明の面光源装置は、凹凸条のピッチ
が不規則になっているから、この面光源装置の前に液晶
を用いる表示装置を置くと、この表示装置にモアレ干渉
縞が発生せず、光が適宜拡散して、見易い画面が得られ
るので、極めて価値がある。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、この凹凸条を当接させて設けると、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、
光の損失がなく輝度が向上するから価値あるものであ
る。In the surface light source device of the present invention, the pitch of the irregular stripes is irregular. Therefore, if a display device using liquid crystal is placed in front of this surface light source device, moire interference fringes will appear on this display device. It is extremely valuable because it does not occur and light is appropriately diffused to provide a screen that is easy to see. Further, 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 is provided in contact with the light, the light efficiently enters the transparent prism film or sheet,
It is valuable because there is no light loss and the brightness is improved.
【００４０】又、透明プリズムフィルムまたはシートの
凹凸条のピッチを２０μｍ〜５００μｍの間に不規則に
配置したり、凹凸条の稜部を曲面にしたり、透明プリズ
ムフィルムまたはシートの凹凸条と反対の面にも凹凸条
を設けたり、凹凸条のピッチを不規則にすると同時に、
凹凸条の傾斜面の傾斜角度も不規則にしたりすると、こ
の面光源装置の前に液晶を用いた表示装置を置いたと
き、この表示装置が見易い画面となるので、価値あるも
のである。Further, the pitch of the uneven strips of the transparent prism film or sheet is irregularly arranged between 20 μm and 500 μm, the ridges of the uneven strips are curved, At the same time as providing uneven lines on the surface and making the pitch of the uneven lines irregular,
If the inclination angle of the inclined surface of the uneven strip is also irregular, when a display device using a liquid crystal is placed in front of this surface light source device, this display device becomes an easy-to-see screen, which is valuable.
【図１】図１は本発明の第１の実施例を示すもので、面
光源装置の断面図である。FIG. 1 shows a first embodiment of the present invention and is a sectional view of a surface light source device.
【図２】図２は本発明の第２の実施例を示すもので、面
光源装置の断面図である。FIG. 2 shows a second embodiment of the present invention and is a sectional view of a surface light source device.
【図３】図３は本発明の第３の実施例を示すもので、面
光源装置の断面図である。FIG. 3 shows a third embodiment of the present invention and is a sectional view of a surface light source device.
【図４】図４は本発明の第４の実施例を示すもので、面
光源装置の断面図である。FIG. 4 shows a fourth embodiment of the present invention and is a sectional view of a surface light source device.
【図５】図５は本発明の面光源装置の効果を比較するた
めに試験した比較例の面光源装置の断面図である。FIG. 5 is a cross-sectional view of a surface light source device of a comparative example, which was tested to compare the effects of the surface light source device of the present invention.
【図６】図５は本発明の面光源装置の効果を比較するた
めに試験した比較例の面光源装置の断面図である。FIG. 5 is a cross-sectional view of a surface light source device of a comparative example, which was tested to compare the effects of the surface light source device of the present invention.
【図７】図７は従来の面光源装置の配光特性を示す説明
図である。FIG. 7 is an explanatory diagram showing a light distribution characteristic of a conventional surface light source device.
【図８】図８は従来の面光源装置の配光特性を示す説明
図である。FIG. 8 is an explanatory diagram showing a light distribution characteristic of a conventional surface light source device.
１ 導光板 ２ 反射板 ３、３ａ、３ｂ 透明プリズムフィルムまた
はシート ５ 光源 ６ 反射板1 Light guide plate 2 Reflector 3, 3a, 3b Transparent prism film or sheet 5 Light source 6 Reflector
Claims (6)
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のピッチが不規
則に配置さ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.
In 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, and a reflecting plate is provided on the back surface of this light guide plate, the pitch of the uneven line of the transparent prism film or sheet 2. A surface light source device characterized by being arranged irregularly.
凹凸条を線状の光源にほぼ平行にして、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,
2. The surface light source device according to claim 1, wherein the uneven line is provided on the surface of the light guide plate so as to be substantially parallel to the linear light source.
凸条のピッチが２０μｍから５００μｍの間で不規則に
配置されていることを特徴とする請求項１又は２記載の
面光源装置。3. The surface light source device according to claim 1, wherein the pitch of the irregular stripes of the transparent prism film or sheet is irregularly arranged within a range of 20 μm to 500 μm.
する請求項１、２又は３記載の面光源装置。4. The surface light source device according to claim 1, 2 or 3, wherein the ridges of the uneven strips are curved surfaces.
が設けられていることを特徴とする請求項１、２、３又
は４記載の面光源装置。5. The surface light source device according to claim 1, wherein the surface of the light guide plate opposite to the surface of the uneven surface is provided with the uneven surface.
ることを特徴とする請求項１、２、３、４又は５記載の
面光源装置。6. The surface light source device according to claim 1, wherein the inclination angle of the inclined surface of the uneven strip is irregular.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5068164A JPH0682635A (en) | 1992-07-07 | 1993-03-26 | Surface light source device |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17976692 | 1992-07-07 | ||
| JP4-186741 | 1992-07-14 | ||
| JP4-179766 | 1992-07-14 | ||
| JP18674192 | 1992-07-14 | ||
| JP5068164A JPH0682635A (en) | 1992-07-07 | 1993-03-26 | Surface light source device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0682635A true JPH0682635A (en) | 1994-03-25 |
Family
ID=27299652
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5068164A Pending JPH0682635A (en) | 1992-07-07 | 1993-03-26 | Surface light source device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0682635A (en) |
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| WO1996016348A1 (en) * | 1994-11-24 | 1996-05-30 | Hitachi Ltd. | Liquid crystal display device |
| WO1997039369A1 (en) * | 1996-04-12 | 1997-10-23 | Minnesota Mining And Manufacturing Company | Variable pitch structured optical film |
| JPH09281340A (en) * | 1996-04-09 | 1997-10-31 | Casio Comput Co Ltd | Light transmission device and its production as well as light source structure formed by using the same |
| WO2000042451A1 (en) * | 1999-01-14 | 2000-07-20 | Minnesota Mining And Manufacturing Company | Optical sheets suitable for spreading light |
| WO2001027663A1 (en) * | 1999-10-08 | 2001-04-19 | 3M Innovative Properties Company | Optical film with variable angle prisms |
| US6447135B1 (en) | 1999-10-08 | 2002-09-10 | 3M Innovative Properties Company | Lightguide having a directly secured reflector and method of making the same |
| WO2002023258A3 (en) * | 2000-09-14 | 2003-02-06 | 3M Innovative Properties Co | Optical sheets suitable for spreading light |
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| JP2022548254A (en) * | 2019-09-11 | 2022-11-17 | キョンブク ナショナル ユニヴァーシティ インダストリー－アカデミック コオペレーション ファウンデーション | Angle of view and coherence actively controlled random refractive element and its manufacturing method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996016348A1 (en) * | 1994-11-24 | 1996-05-30 | Hitachi Ltd. | Liquid crystal display device |
| JPH09281340A (en) * | 1996-04-09 | 1997-10-31 | Casio Comput Co Ltd | Light transmission device and its production as well as light source structure formed by using the same |
| WO1997039369A1 (en) * | 1996-04-12 | 1997-10-23 | Minnesota Mining And Manufacturing Company | Variable pitch structured optical film |
| US5919551A (en) * | 1996-04-12 | 1999-07-06 | 3M Innovative Properties Company | Variable pitch structured optical film |
| AU727440B2 (en) * | 1996-04-12 | 2000-12-14 | Minnesota Mining And Manufacturing Company | Variable pitch structured optical film |
| US6456437B1 (en) | 1999-01-14 | 2002-09-24 | 3M Innovative Properties Company | Optical sheets suitable for spreading light |
| WO2000042451A1 (en) * | 1999-01-14 | 2000-07-20 | Minnesota Mining And Manufacturing Company | Optical sheets suitable for spreading light |
| US6447135B1 (en) | 1999-10-08 | 2002-09-10 | 3M Innovative Properties Company | Lightguide having a directly secured reflector and method of making the same |
| US6356391B1 (en) | 1999-10-08 | 2002-03-12 | 3M Innovative Properties Company | Optical film with variable angle prisms |
| WO2001027663A1 (en) * | 1999-10-08 | 2001-04-19 | 3M Innovative Properties Company | Optical film with variable angle prisms |
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