JPH08334625A - Light transmission plate and back light - Google Patents
Light transmission plate and back lightInfo
- Publication number
- JPH08334625A JPH08334625A JP7139194A JP13919495A JPH08334625A JP H08334625 A JPH08334625 A JP H08334625A JP 7139194 A JP7139194 A JP 7139194A JP 13919495 A JP13919495 A JP 13919495A JP H08334625 A JPH08334625 A JP H08334625A
- Authority
- JP
- Japan
- Prior art keywords
- light
- guide plate
- projections
- light guide
- light source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Liquid Crystal (AREA)
- Planar Illumination Modules (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、液晶表示素子を後方か
ら照射するエッジライト方式のバックライト及びそれに
用いられる導光板に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge light type backlight for illuminating a liquid crystal display device from the rear side and a light guide plate used for the same.
【０００２】[0002]
【従来の技術】バックライトの低消費電力のためには、
バックライトの各素子の光利用効率を高める必要があ
る。導光板に対しては、光の吸収のある印刷導光板に代
って光の吸収の少ない非拡散方式の導光板に注目が集ま
っている。2. Description of the Related Art For low power consumption of a backlight,
It is necessary to improve the light utilization efficiency of each element of the backlight. As for the light guide plate, attention has been focused on a non-diffusion type light guide plate that absorbs less light, instead of a printed light guide plate that absorbs light.
【０００３】図８は特開平6-250024号公報で開示された
非拡散導光板の構成図である。図において、導光板１か
ら外部への出射方法として、プリズム(突起)２を導光板
１の透過面６に断面形状がのこ歯状に形成するととも
に、プリズム２の頂角θを光源から遠ざかる程小さくな
るように形成している。FIG. 8 is a block diagram of a non-diffusing light guide plate disclosed in Japanese Patent Laid-Open No. 6-250024. In the figure, as a method of emitting light from the light guide plate 1 to the outside, a prism (projection) 2 is formed on the transmissive surface 6 of the light guide plate 1 in a sawtooth cross section, and the apex angle θ of the prism 2 is moved away from the light source. It is formed so that it becomes smaller.
【０００４】これにより、光源４から遠い場所での光線
の出射方向を透過面６の法線方向に向けている。As a result, the emission direction of the light rays at a location far from the light source 4 is directed in the direction normal to the transmitting surface 6.
【０００５】[0005]
【発明が解決しようとする課題】しかし、上記構成の導
光板においては、導光板１を全体的に見ると、プリズム
２の頂角θは変化しているが、局所的に見ると、略同一
形状のプリズムである。However, in the light guide plate having the above-mentioned structure, the apex angle θ of the prism 2 changes when the light guide plate 1 is viewed as a whole, but when viewed locally, it is substantially the same. It is a prism of shape.
【０００６】従って、出射光線の半値角、即ち、最大輝
度の半分以上の輝度を有する角度範囲が狭く、輝度が高
いか、出射光線の半値角が広いが、輝度が低いかのどち
らかになるという問題点がある。Therefore, the half-value angle of the outgoing light beam, that is, the angular range having a brightness of more than half the maximum brightness is narrow and the brightness is high, or the half-value angle of the outgoing light beam is wide but the brightness is low. There is a problem.
【０００７】更に、導光板１の長さ方向で、プリズムが
連続形成されているので、長さ方向において、輝度むら
が発生する問題点もある。本発明は、上記問題点に鑑み
てなされたもので、その第１の目的は、出射光線の半値
角が広く、輝度も高い導光板及びバックライトを提供す
ることにある。Further, since the prisms are continuously formed in the lengthwise direction of the light guide plate 1, there is a problem that uneven brightness occurs in the lengthwise direction. The present invention has been made in view of the above problems, and a first object thereof is to provide a light guide plate and a backlight having a wide half-value angle of emitted light and high brightness.
【０００８】第２の目的は、モアレが発生しない導光板
を提供することにある。A second object is to provide a light guide plate free from moire.
【０００９】[0009]
【課題を解決するための手段】上記課題を解決する第１
の発明の導光板は、液晶表示素子を後方から照射するエ
ッジライト方式のバックライトに用いられる導光板にお
いて、前記導光板の透過面もしくは反射面のうちのいず
れかの面に直線状に延び、かつ断面形状が複数形状の突
起または溝を形成すると共に、前記複数の形状の突起ま
たは溝は局所的に混在しているものである。Means for Solving the Problems A first method for solving the above problems is described below.
The light guide plate of the invention of, in a light guide plate used for a backlight of an edge light system that irradiates a liquid crystal display element from behind, extends linearly on any one of the transmission surface or the reflection surface of the light guide plate, Moreover, the projections or grooves having a plurality of cross-sectional shapes are formed, and the projections or grooves having the plurality of shapes are locally mixed.
【００１０】ここで、前記複数種類の突起または溝の構
成割合が光源から遠ざかるにつれて変化することが望ま
しい。具体的には、前記突起は断面形状が三角形で、光
源に近い箇所では、反光源側傾斜面の傾斜角度が大きい
突起の割合が大きく、光源から遠い箇所では、反光源側
傾斜面の傾斜角度が小さな突起の割合が大きいことが望
ましい。Here, it is desirable that the composition ratios of the plurality of types of protrusions or grooves change as the distance from the light source increases. Specifically, the protrusion has a triangular cross-sectional shape, the inclination angle of the anti-light source side inclined surface is large at a portion near the light source, and the inclination angle of the anti-light source side inclined surface is large at a portion far from the light source. It is desirable that the proportion of small protrusions is large.
【００１１】また、前記突起は、アンダーカット部の無
いことが望ましい。更に、前記突起または溝は、前記液
晶表示素子の液晶画素の配列方向と交差するように設け
ることが望ましい。Further, it is desirable that the protrusion has no undercut portion. Further, it is preferable that the protrusions or grooves are provided so as to intersect the arrangement direction of the liquid crystal pixels of the liquid crystal display element.
【００１２】第２の発明のバックライトは、透過面もし
くは反射面のうちのいずれかの面に複数形状の突起また
は溝を形成すると共に、前記複数の形状の突起または溝
は局所的に混在している導光板を有するものである。In the backlight of the second invention, a plurality of projections or grooves having a plurality of shapes are formed on any one of the transmitting surface and the reflecting surface, and the projections or grooves having the plurality of shapes are locally mixed. It has a light guide plate.
【００１３】[0013]
【作用】第１の発明の導光板において、輝度と半値角の
異なる複数の形状の突起または溝が局所的に混在してい
るので、導光板からの出射特性も各突起固有の出射特性
が合成され、輝度も高く、半値角も広くなる。In the light guide plate according to the first aspect of the present invention, since a plurality of protrusions or grooves having different brightness and half-value angle are locally mixed, the emission characteristics from the light guide plate are also combined with the emission characteristics unique to each protrusion. As a result, the brightness is high and the half-value angle is wide.
【００１４】突起に入射する光の角度分布は光源からの
距離に応じて変化するが、突起または溝の構成割合を光
源からの距離に応じて、言うなれば、突起に入射する光
の角度分布に応じて、複数形状の突起または溝の構成割
合を決定しているので、導光板からの出射特性(角度分
布及び出射角度特性)が光源からの距離に関わらず略一
定となる。The angle distribution of the light incident on the projection changes according to the distance from the light source, but the composition ratio of the projection or the groove depends on the distance from the light source, that is, the angular distribution of the light incident on the projection. Since the composition ratios of the protrusions or grooves having a plurality of shapes are determined according to the above, the emission characteristics (angle distribution and emission angle characteristics) from the light guide plate are substantially constant regardless of the distance from the light source.
【００１５】具体的に、突起は断面形状が三角形で、光
量が多い光源に近い箇所では、反光源側傾斜面の傾斜角
度が大きい突起の割合が大きくすることにより、導光板
からの出射光量を少なくし、光量が減少する光源から遠
い箇所では、反光源側傾斜面の傾斜角度が小さな突起の
割合が大きくして、導光板からの出射光量を多くする。Specifically, the protrusion has a triangular cross-section, and at a portion near the light source with a large amount of light, the proportion of the protrusion with a large inclination angle of the anti-light source side inclined surface is increased, so that the amount of light emitted from the light guide plate is increased. At a location far from the light source where the amount of light is reduced, the amount of light emitted from the light guide plate is increased by increasing the proportion of protrusions having a small inclination angle on the anti-light source side inclined surface.
【００１６】更に、突起または溝には、アンダーカット
部が無い形状としたことにより、型抜き成形で突起を形
成することができ、大量生産が可能となる。また、前記
突起または溝は、前記液晶表示素子の液晶画素の配列方
向と交差するように設けられるようにすることにより、
モアレの発生がなくなる。Further, since the projection or the groove has a shape without an undercut portion, the projection can be formed by die-cutting molding, which enables mass production. Further, the protrusions or grooves are provided so as to intersect with the arrangement direction of the liquid crystal pixels of the liquid crystal display element,
Moire is eliminated.
【００１７】第２の発明のバックライトにおいて、輝度
と半値角の異なる複数の形状の突起または溝が局所的に
混在しているので、導光板からの出射特性も各突起固有
の出射特性が合成され、輝度も高く、半値角も広くな
る。In the backlight of the second aspect of the present invention, since a plurality of projections or grooves having different brightness and half-value angle are locally mixed, the emission characteristics from the light guide plate are also combined with the emission characteristics unique to each projection. As a result, the brightness is high and the half-value angle is wide.
【００１８】[0018]
【実施例】次に図面を用いて本発明の一実施例を説明す
る。図１は本発明の一実施例の導光板の断面図、図２は
図１における上面図、図３は図１における突起A,突起B
を説明する図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to the drawings. 1 is a sectional view of a light guide plate according to an embodiment of the present invention, FIG. 2 is a top view of FIG. 1, and FIG. 3 is a projection A and a projection B of FIG.
It is a figure explaining.
【００１９】先ず、図１及び図２を用いて本発明の一実
施例の導光板の構成を説明する。図において、１１は管
状の光源、１２は光源１１からの光を導光する導光板で
ある。導光板の材質としては、内部透過率の高いものが
良く、コスト・重量の点からプラスチック材料が良く、
本実施例の導光板１２は、アクリルを用いた。更に、本
実施例の導光板１２の大きさは、長さ180mm,幅(図面に
垂直方向)216mm,光源１１側の厚さ3mm,反光源側の厚さ2
mmの断面形状がテーパ状のものを用いた。First, the structure of the light guide plate of one embodiment of the present invention will be described with reference to FIGS. In the figure, 11 is a tubular light source, and 12 is a light guide plate for guiding the light from the light source 11. As a material for the light guide plate, a material having a high internal transmittance is preferable, and a plastic material is preferable in terms of cost and weight.
Acrylic is used for the light guide plate 12 of this embodiment. Further, the size of the light guide plate 12 of this embodiment is 180 mm in length, 216 mm in width (perpendicular to the drawing), 3 mm in thickness on the light source 11 side, and 2 in thickness on the side opposite to the light source 2.
A mm cross-section having a tapered shape was used.
【００２０】ここで、導光板１２の一方の面を透過面１
３、他方の面を反射面１４、光源１１の光が入射する面
を入射面１５と規定すると、透過面１３上には、断面形
状が三角形の微小突起１６が形成されている。また、本
実施例の突起１６は、光源１１と交差するように設けら
れ、液晶表示素子１９の液晶画素の配列方向と交差する
ようになっている。Here, one surface of the light guide plate 12 is attached to the transparent surface 1.
3, the other surface is defined as the reflecting surface 14, and the surface on which the light of the light source 11 is incident is defined as the incident surface 15. On the transmissive surface 13, minute protrusions 16 having a triangular sectional shape are formed. Further, the protrusion 16 of the present embodiment is provided so as to intersect with the light source 11, and intersects with the arrangement direction of the liquid crystal pixels of the liquid crystal display element 19.
【００２１】更に、突起１６は導光板の幅方向におい
て、突起１６の高さが変化している。具体的には、導光
板の幅方向の周辺部で突起の高さが高くなっている。ま
た、１７は液晶表示素子１９と導光板１２との間に配設
され、導光板１２〜出射する光を拡散する拡散シート、
１８は拡散シート１７によって拡散された光を集光する
集光シートである。Further, the height of the projection 16 varies in the width direction of the light guide plate. Specifically, the height of the protrusion is high at the peripheral portion in the width direction of the light guide plate. Further, 17 is disposed between the liquid crystal display element 19 and the light guide plate 12, and the light guide plate 12 to a diffusion sheet for diffusing emitted light,
Reference numeral 18 denotes a light collecting sheet that collects the light diffused by the diffusion sheet 17.
【００２２】本実施例の突起１６は、図３に示すよう
に、形状の異なる二種類の突起即ち突起A１６′と突起B
１６″とからなっている。ここで、基準面である透過面
１３と突起１６の反光源側の傾斜面(反光源側突起斜面)
とのなす角αを突起傾斜角度、突起１６の二つの斜面の
なす角θを突起頂角と規定すると、本実施例の突起A１
６′の突起頂角θは65°、突起傾斜角度αは92°、突起
B１６″の突起頂角θは90°、突起傾斜角度αは135°と
し、アンダーカット部が無い形状とした。As shown in FIG. 3, the protrusion 16 of this embodiment has two types of protrusions having different shapes, that is, a protrusion A16 'and a protrusion B.
16 ″. Here, the transmission surface 13 as the reference surface and the inclined surface of the projection 16 on the side opposite to the light source (anti-light source side projection inclined surface)
Assuming that the angle α formed by and the projection inclination angle is defined as the projection inclination angle, and the angle θ formed by the two slopes of the projection 16 is defined as the projection apex angle.
6 ′ has a projection apex angle θ of 65 °, a projection inclination angle α of 92 °, and a projection
The protrusion apex angle θ of B16 ″ was 90 °, the protrusion inclination angle α was 135 °, and there was no undercut portion.
【００２３】そして、導光板１２の透過面１３上に形成
された突起A１６′及び突起B１６″は、局所的に混在
し、更に、光源１１からの距離に応じて、これら二つの
突起の割合を変化させた。具体的には、光源１１に近い
場所では突起傾斜角度θが大きな突起B１６″の割合が
多く、光源１１から遠い場所では突起傾斜角度θが小さ
な突起A１６′の割合が多くなるように形成した。The projections A16 'and the projections B16 "formed on the transmissive surface 13 of the light guide plate 12 are locally mixed, and the proportion of these two projections is determined according to the distance from the light source 11. Specifically, the proportion of the protrusions B16 ″ having a large protrusion inclination angle θ is large in a place close to the light source 11, and the proportion of the protrusions A16 ′ having a small protrusion inclination angle θ is large in a place far from the light source 11. Formed.
【００２４】次に上記構成の動作を説明する。光源１１
から発せられた光は導光板１２の入射面１５から導光板
１２内部に入っていく。導光板１２内を導光する光が突
起１６に入射すると、主に反光源側突起斜面にぶつか
り、その一部は導光板１２外へ出射する。Next, the operation of the above configuration will be described. Light source 11
The light emitted from the inside enters the inside of the light guide plate 12 from the incident surface 15 of the light guide plate 12. When the light guided inside the light guide plate 12 is incident on the protrusion 16, it mainly hits the slope of the protrusion opposite to the light source side, and a part thereof is emitted to the outside of the light guide plate 12.
【００２５】また、光源側突起斜面に光が入射すると、
光源側突起斜面で全反射した光線の一部が反光源側突起
斜面から導光板外部に出射する。次に、本実施例の導光
板における出射光の分布を図４〜図７を用いて説明す
る。When light is incident on the slope of the light source side projection,
A part of the light beam totally reflected by the light source side protrusion slope is emitted from the anti-light source side protrusion slope to the outside of the light guide plate. Next, the distribution of emitted light in the light guide plate of this embodiment will be described with reference to FIGS.
【００２６】(1) 光源１１に近い場所 図４は光源１１から40mmで導光板１２の幅方向の略中央
部における突起A１６′と突起B１６″における出射光線
の角度特性を示している。尚、この箇所における突起A
１６′と突起B１６″との構成割合(透過面の単位面積1m
m2に占める突起の投影面積の割合)は、突起A１６′:突
起B１６″= 1:5である。(1) Location near the light source 11 FIG. 4 shows the angular characteristics of the emitted light rays at the protrusion A16 'and the protrusion B16 "at approximately 40 mm from the light source 11 in the widthwise direction of the light guide plate 12. Protrusion A at this point
16 'and protrusion B16 "(the unit area of the transmission surface is 1 m
The ratio of the projected area of the projection to m 2 ) is projection A16 ′: projection B16 ″ = 1: 5.
【００２７】図に示すように、突起傾斜角度αが大きな
突起B１６″(破線)の方が、突起傾斜角度αが小さな突
起A１６′より最大輝度は低いが、半値角が広くなる特
性を有している。As shown in the figure, the projection B16 "(broken line) having a large projection inclination angle α has a characteristic that the maximum brightness is lower but the half-value angle is wider than the projection A16 'having a small projection inclination angle α. ing.
【００２８】図５はこの場所での突起A１６′と突起B１
６″の合成出射角度特性を示す。これら出射特性の異な
る２つの突起A１６′と突起B１６″を混在させたことに
より、輝度が高く、半値角の大きな光線が導光板１２よ
り出射していることがわかる。FIG. 5 shows the protrusion A16 'and the protrusion B1 at this location.
6 ″ shows a combined emission angle characteristic of 6 ″. Since two projections A16 ′ and a projection B16 ″ having different emission characteristics are mixed, a light beam having high brightness and a large half value angle is emitted from the light guide plate 12. I understand.
【００２９】(2) 光源１１から遠い場所 図６は光源１１から140mmで導光板１２の幅方向の略中
央部における突起A１６′と突起B１６″における出射光
線の角度特性を示している。尚、この箇所における突起
A１６′と突起B１６″との構成割合は、突起A１６′:突
起B１６″= 2:1である。(2) Place far from the light source 11 FIG. 6 shows the angular characteristics of the emitted light rays at the protrusion A16 'and the protrusion B16 "at approximately 140 mm from the light source 11 in the substantially central portion of the light guide plate 12 in the width direction. Protrusion at this location
The composition ratio of A16 ′ and protrusion B16 ″ is protrusion A16 ′: protrusion B16 ″ = 2: 1.
【００３０】図４と同様に、突起傾斜角度αが大きな突
起B１６″(破線)の方が、突起傾斜角度αが小さな突起A
１６′より輝度は低いが、半値角が広くなる特性を有し
ている。Similar to FIG. 4, the protrusion B16 ″ (broken line) having a larger protrusion inclination angle α has a smaller protrusion inclination angle α.
The brightness is lower than that of 16 ', but the half-value angle is wide.
【００３１】図７はこの場所での突起A１６′と突起B１
６″の合成出射角度特性を示す。図５と同様に、これら
出射特性の異なる２つの突起A１６′と突起B１６″を混
在させたことにより、輝度が高く、半値角の大きな光線
が導光板１２より出射していることがわかる。FIG. 7 shows the protrusion A16 'and the protrusion B1 at this location.
6 shows a composite emission angle characteristic of 6 ″. Similar to FIG. 5, by mixing two protrusions A16 ′ and a protrusion B16 ″ having different emission characteristics, a light beam with high brightness and a large half-value angle is formed on the light guide plate 12. You can see that it is emitting more.
【００３２】上記構成によれば、下記のような効果を得
ることができる。 (1) 輝度と半値角が異なる、二種類の突起A１６′と突
起B１６″とが局所的に混在しているので、合成され、
輝度も高く、半値角も広くなる。According to the above structure, the following effects can be obtained. (1) Since two kinds of protrusions A16 ′ and B16 ″ having different brightness and half-value angle are locally mixed, they are combined,
The brightness is high and the half-value angle is wide.
【００３３】(2) 導光板１２の突起に入射する光の角度
分布は光源からの距離の応じて変化し、突起に入射する
光量も光源からの距離に応じて変化する。ここで、突起
１６の構成割合を、光量が多い光源１１に近い箇所で
は、反光源側傾斜面αの傾斜角度が大きい突起B１６″
の割合が大きくすることにより、導光板１２からの出射
光量を少なくし、光量が減少する光源１１から遠い箇所
では、反光源側傾斜面の傾斜角度αが小さな突起A１
６′の割合が大きくして、導光板１２からの出射光量を
多くし、導光板１２全体から略同じ光量を出射させるこ
とができる。(2) The angular distribution of light incident on the protrusion of the light guide plate 12 changes according to the distance from the light source, and the amount of light incident on the protrusion also changes according to the distance from the light source. Here, the ratio of the protrusions 16 is set to be a protrusion B16 ″ in which the inclination angle of the anti-light source side inclined surface α is large in a portion close to the light source 11 having a large amount of light.
The amount of light emitted from the light guide plate 12 is reduced and the amount of light emitted from the light guide plate 12 is reduced.
By increasing the ratio of 6 ', the amount of light emitted from the light guide plate 12 can be increased, and substantially the same amount of light can be emitted from the entire light guide plate 12.
【００３４】(3) 突起１６には、アンダーカット部が無
い形状としたことにより、型抜き成形で突起１６を形成
することができ、大量生産が可能となる。 (4) 直線状に延びた突起１６を図２にもあるように、線
状の光源と平行な液晶画素の配列方向と交差するように
設けたことにより、突起１６と液晶画素とで発生するモ
アレの影響を緩和することができる。また、導光板１２
と液晶素子との間に、正面方向への輝度を高めるプリズ
ム状集光シートをプリズムの稜線が線状の光源と平行介
入させた場合も、導光板１２の突起１６と集光シートの
プリズムとで発生するモアレの影響を緩和することがで
きる。(3) Since the protrusion 16 has a shape without an undercut portion, the protrusion 16 can be formed by die-cutting molding, which enables mass production. (4) As shown in FIG. 2, the linearly extending projection 16 is provided so as to intersect the alignment direction of the liquid crystal pixels parallel to the linear light source, so that the projections 16 and the liquid crystal pixels are generated. The effect of moire can be mitigated. In addition, the light guide plate 12
Even when a prism-shaped light-condensing sheet for enhancing the brightness in the front direction is interposed between the liquid crystal element and the liquid crystal element in parallel with the light source whose prism ridge is linear, the projection 16 of the light guide plate 12 and the prism of the light-condensing sheet It is possible to mitigate the influence of moire that occurs in.
【００３５】(5) 突起１６の高さを導光板１２の幅方向
の周辺部で高さが高くなるように形成したので、光源１
１自体が持つ導光板１２の幅方向の発光むらを補正し、
導光板１２の幅方向の輝度むらを減少させることができ
る。(5) Since the height of the protrusion 16 is formed so as to be higher in the peripheral portion of the light guide plate 12 in the width direction, the light source 1
Corrects the unevenness of light emission in the width direction of the light guide plate 12 which 1 itself has,
The uneven brightness in the width direction of the light guide plate 12 can be reduced.
【００３６】尚、本発明は上記実施例に限定するもので
はない。上記実施例では、導光板１２の透過面１３に突
起を形成した例で説明を行なったが、透過面１３に溝を
形成してもよい。更に、反射面１４に突起や溝を形成し
てもよい。The present invention is not limited to the above embodiment. In the above-described embodiment, the description is given of the example in which the projection is formed on the transmissive surface 13 of the light guide plate 12, but the groove may be formed on the transmissive surface 13. Furthermore, protrusions or grooves may be formed on the reflecting surface 14.
【００３７】更に、上記実施例では、突起の種類を二種
類としたが、三種類以上の突起を局所的に混在させても
よい。Further, in the above embodiment, the types of protrusions are two, but three or more types of protrusions may be locally mixed.
【００３８】[0038]
【発明の効果】以上述べたように第１の発明の導光板に
よれば、輝度と半値角の異なる複数の形状の突起または
溝が局所的に混在しているので、導光板からの出射特性
も各突起固有の出射特性が合成され、輝度も高く、半値
角も広くなる。As described above, according to the light guide plate of the first invention, a plurality of projections or grooves having different brightness and half-value angle are locally mixed, so that the emission characteristics from the light guide plate are improved. In addition, the emission characteristics unique to each protrusion are combined, the brightness is high, and the half-value angle is wide.
【００３９】突起に入射する光の角度分布は光源からの
距離に応じて変化するが、突起または溝の構成割合を光
源からの距離に応じて、言うなれば、突起に入射する光
の角度分布に応じて、複数形状の突起または溝の構成割
合を決定しているので、導光板からの出射特性(角度分
布及び出射角度特性)が光源からの距離に関わらず略一
定となる。The angular distribution of the light incident on the projection changes according to the distance from the light source, but the composition ratio of the projection or the groove depends on the distance from the light source, that is, the angular distribution of the light incident on the projection. Since the composition ratios of the protrusions or grooves having a plurality of shapes are determined according to the above, the emission characteristics (angle distribution and emission angle characteristics) from the light guide plate are substantially constant regardless of the distance from the light source.
【００４０】具体的に、突起は断面形状が三角形で、光
量が多い光源に近い箇所では、反光源側傾斜面の傾斜角
度が大きい突起の割合が大きくすることにより、導光板
からの出射光量を少なくし、光量が減少する光源から遠
い箇所では、反光源側傾斜面の傾斜角度が小さな突起の
割合が大きくして、導光板からの出射光量を多くする。Specifically, the protrusion has a triangular cross-section, and at a portion near the light source with a large amount of light, the proportion of the protrusion with a large inclination angle of the anti-light source side inclined surface is increased so that the amount of light emitted from the light guide plate is increased. At a location far from the light source where the amount of light is reduced, the amount of light emitted from the light guide plate is increased by increasing the proportion of protrusions having a small inclination angle on the anti-light source side inclined surface.
【００４１】更に、突起または溝には、アンダーカット
部が無い形状としたことにより、型抜き成形で突起を形
成することができ、大量生産が可能となる。また、前記
突起または溝は、前記液晶表示素子の液晶画素の配列方
向と交差するように設けられるようにすることにより、
モアレの発生がなくなる。Further, since the projections or grooves have a shape without an undercut portion, the projections can be formed by die-cutting molding, which enables mass production. Further, the protrusions or grooves are provided so as to intersect with the arrangement direction of the liquid crystal pixels of the liquid crystal display element,
Moire is eliminated.
【００４２】第２の発明のバックライトによれば、輝度
と半値角の異なる複数の形状の突起または溝が局所的に
混在しているので、導光板からの出射特性も各突起固有
の出射特性が合成され、輝度も高く、半値角も広くな
る。According to the backlight of the second aspect of the present invention, since a plurality of protrusions or grooves having different brightness and half-value angle are locally mixed, the emission characteristic from the light guide plate is also the emission characteristic peculiar to each protrusion. Are combined, the brightness is high, and the half-value angle is wide.
【図１】本発明の一実施例の導光板の断面図である。FIG. 1 is a cross-sectional view of a light guide plate according to an embodiment of the present invention.
【図２】図１における上面図である。FIG. 2 is a top view of FIG.
【図３】図１における突起A,突起Bを説明する図であ
る。FIG. 3 is a diagram illustrating a protrusion A and a protrusion B in FIG.
【図４】図１に示す構成において、光源から40mmで導光
板の幅方向に略中央部における突起Aと突起Bにおける出
射光線の角度特性を示す図である。FIG. 4 is a diagram showing angular characteristics of outgoing rays at a projection A and a projection B at a substantially central portion in the width direction of the light guide plate at 40 mm from the light source in the configuration shown in FIG. 1.
【図５】図４における突起Aと突起Bとの合成出射角度特
性を示す図である。5 is a diagram showing a combined emission angle characteristic of a protrusion A and a protrusion B in FIG.
【図６】図１に示す構成において、光源から140mmで導
光板の幅方向に略中央部における突起Aと突起Bにおける
出射光線の角度特性を示す図である。FIG. 6 is a diagram showing angular characteristics of outgoing rays at a protrusion A and a protrusion B at approximately 140 mm from the light source in the width direction of the light guide plate in the configuration shown in FIG.
【図７】図６における突起Aと突起Bとの合成出射角度特
性を示す図である。7 is a diagram showing a combined emission angle characteristic of a protrusion A and a protrusion B in FIG.
【図８】特開平6-250024号公報で開示された非拡散導光
板の構成図である。FIG. 8 is a configuration diagram of a non-diffusing light guide plate disclosed in Japanese Patent Laid-Open No. 6-250024.
１１ 光源 １２ 導光板 １３ 透過面 １４ 反射面 １５ 入射面 １６ 突起 １６′ 突起A １６″ 突起B 11 Light source 12 Light guide plate 13 Transmission surface 14 Reflection surface 15 Incident surface 16 Protrusion 16 'Protrusion A 16 "Protrusion B
Claims (6)
ライト方式のバックライトに用いられる導光板におい
て、 前記導光板の透過面もしくは反射面のうちのいずれかの
面に直線状に延び、かつ断面形状が複数形状の突起また
は溝を形成すると共に、 前記複数の形状の突起または溝は局所的に混在している
ことを特徴とする導光板。1. A light guide plate used for an edge light type backlight, which illuminates a liquid crystal display device from the rear, wherein the light guide plate linearly extends on any one of a transmissive surface and a reflective surface and has a cross section. A light guide plate, wherein projections or grooves having a plurality of shapes are formed, and the projections or grooves having the plurality of shapes are locally mixed.
が光源から遠ざかるにつれて変化することを特徴とする
請求項１記載の導光板。2. The light guide plate according to claim 1, wherein the composition ratios of the plurality of types of protrusions or grooves change as the distance from the light source increases.
い突起の割合が大きく、 光源から遠い箇所では、反光源側傾斜面の傾斜角度が小
さな突起の割合が大きいことを特徴とする請求項１また
は２記載の導光板。3. The protrusion has a triangular cross-section, and the proportion of protrusions having a large inclination angle of the anti-light source side inclined surface is large in a portion close to the light source, and the inclination angle of the anti-light source side inclined surface is large in a portion far from the light source. 3. The light guide plate according to claim 1, wherein the small protrusions have a large proportion.
とを特徴とする請求項１乃至３いずれかに記載の導光
板。4. The light guide plate according to claim 1, wherein the protrusion has no undercut portion.
の液晶画素の配列方向と交差するように設けられること
を特徴とする請求項１乃至４いずれかに記載の導光板。5. The light guide plate according to claim 1, wherein the protrusion or the groove is provided so as to intersect with an arrangement direction of liquid crystal pixels of the liquid crystal display element.
の面に複数形状の突起または溝を形成すると共に、 前記複数の形状の突起または溝は局所的に混在している
導光板を有することを特徴とするバックライト。6. A light guide plate in which a plurality of protrusions or grooves having a plurality of shapes are formed on any one of the transmitting surface and the reflecting surface, and the protrusions or grooves having a plurality of shapes are locally mixed. Backlight characterized by.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7139194A JPH08334625A (en) | 1995-06-06 | 1995-06-06 | Light transmission plate and back light |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7139194A JPH08334625A (en) | 1995-06-06 | 1995-06-06 | Light transmission plate and back light |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08334625A true JPH08334625A (en) | 1996-12-17 |
Family
ID=15239752
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7139194A Pending JPH08334625A (en) | 1995-06-06 | 1995-06-06 | Light transmission plate and back light |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08334625A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL1015024C2 (en) * | 1999-04-26 | 2001-05-08 | Nitto Denko Corp | Liquid crystal display device. |
| KR20020066788A (en) * | 2001-02-13 | 2002-08-21 | 심충건 | Light Guide Panel in LCD device with a latticed V-extruded type pattern and the manufacturing method of it |
| KR20020083886A (en) * | 2001-06-08 | 2002-11-04 | 화우테크놀러지 주식회사 | Light guide panel of backlight unit |
| JP2010067568A (en) * | 2008-09-12 | 2010-03-25 | Fujifilm Corp | Light guide plate |
| JP2016035404A (en) * | 2014-08-01 | 2016-03-17 | オムロン株式会社 | Optical sensor and design method of light guide plate |
-
1995
- 1995-06-06 JP JP7139194A patent/JPH08334625A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL1015024C2 (en) * | 1999-04-26 | 2001-05-08 | Nitto Denko Corp | Liquid crystal display device. |
| US6556259B1 (en) | 1999-04-26 | 2003-04-29 | Nitto Denko Corporation | Liquid-crystal display device |
| KR20020066788A (en) * | 2001-02-13 | 2002-08-21 | 심충건 | Light Guide Panel in LCD device with a latticed V-extruded type pattern and the manufacturing method of it |
| KR20020083886A (en) * | 2001-06-08 | 2002-11-04 | 화우테크놀러지 주식회사 | Light guide panel of backlight unit |
| JP2010067568A (en) * | 2008-09-12 | 2010-03-25 | Fujifilm Corp | Light guide plate |
| JP2016035404A (en) * | 2014-08-01 | 2016-03-17 | オムロン株式会社 | Optical sensor and design method of light guide plate |
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