JP2001126521A - Light guide plate and plane illuminating device - Google Patents
Light guide plate and plane illuminating deviceInfo
- Publication number
- JP2001126521A JP2001126521A JP30425999A JP30425999A JP2001126521A JP 2001126521 A JP2001126521 A JP 2001126521A JP 30425999 A JP30425999 A JP 30425999A JP 30425999 A JP30425999 A JP 30425999A JP 2001126521 A JP2001126521 A JP 2001126521A
- Authority
- JP
- Japan
- Prior art keywords
- light
- surface portion
- guide plate
- face
- light guide
- 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]
【発明の属する技術分野】本発明は、側端面から導入し
た光を表面から均一に出射させるための導光板およびこ
の導光板を用いた平面照明装置に関し、特に大型の透過
型液晶ディスプレイの照明光源として好適なものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate for uniformly emitting light introduced from a side end face from a surface thereof, and a flat lighting device using the light guide plate, and more particularly to an illumination light source for a large transmission type liquid crystal display. It is suitable as.
【０００２】[0002]
【従来の技術】透過型液晶ディスプレイのバックライト
光源として使用される平面照明装置は、光源である冷陰
極管（ＦＣＬ）やＬＥＤアレイなどの光を透明な導光板
の側端面から導き、導光板内での光の全反射などを利用
して導光板の表面部全域から均一に出射させるようにし
たものである。このため、透過型液晶ディスプレイに対
して平面照明装置に要求される機能としては、薄く軽量
であって光源に対する出射光の変換効率が高く、しかも
均一であることが重要である。2. Description of the Related Art A flat lighting device used as a backlight light source for a transmission type liquid crystal display is a light guide plate in which light such as a cold cathode fluorescent lamp (FCL) or an LED array as a light source is guided from a side end face of a transparent light guide plate. The light is uniformly emitted from the entire surface of the light guide plate by utilizing the total reflection of the light inside. For this reason, it is important for the transmission type liquid crystal display to have a function required for the flat illumination device to be thin and lightweight, to have high conversion efficiency of the emitted light to the light source, and to be uniform.
【０００３】このような観点から、従来の導光板は、そ
の裏面部に散乱物質を混入した白インクなどのドット印
刷を施し、これらドット印刷部で光を表面部側に全反射
させずに乱反射させたり、あるいは導光板の表面部や裏
面部に微細な凹凸などによる梨地加工を施し、これによ
り光を散乱させて表面部から一様な光を出射させるよう
にしたものが知られている。[0003] From such a viewpoint, the conventional light guide plate is subjected to dot printing of white ink or the like containing a scattering substance on the back surface thereof, and the light is irregularly reflected at these dot printed portions without totally reflecting light to the front surface side. There is known a light guide plate in which a surface portion or a back surface portion of the light guide plate is subjected to a satin finish process with fine irregularities, thereby scattering light and emitting uniform light from the surface portion.
【０００４】具体的には、導光板の裏面部に白色インク
などを印刷する場合、特開昭６０−２０５５７６号公報
に開示されているようなガラスビーズをインクに混入さ
せたり、特開平２−１２６５０１号公報に示すように白
色系顔料や蛍光顔料の添加量を可及的に滅少させると共
にガラスビーズを含む淡濃度化インクを印刷する方法が
周知である。また、特開平８−２６２４４１号公報に開
示されているように導光板の表面部あるいは裏面部に均
一な粗面加工を施し、さらにプリズムシートを導光板と
平行に重ね合わせたものが知られている。Specifically, when printing white ink or the like on the back surface of the light guide plate, glass beads as disclosed in JP-A-60-205576 may be mixed with the ink, As disclosed in Japanese Patent No. 126501, a method of printing a light-density ink containing glass beads while reducing the amount of a white pigment or a fluorescent pigment as much as possible is well known. Further, as disclosed in Japanese Patent Application Laid-Open No. 8-262441, a light guide plate is known in which a surface portion or a back surface portion is subjected to uniform roughening, and a prism sheet is further overlapped in parallel with the light guide plate. I have.
【０００５】[0005]
【発明が解決しようとする課題】特開昭６０−２０５５
７６号公報に記載されているようにガラスビーズを混入
させた白色インクを用いたり、特開平２−１２６５０１
号公報に記載されているように白色系顔料や蛍光顔料の
添加量を可及的に滅少すると共にガラスビーズを含む淡
濃度化インクを用いたものでは、白色インクの部分での
光の損失が発生し、裏面部での光の全反射を利用するこ
とができないので、輝度の高い光を表面部から出射させ
ることができない。SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. 60-2055
No. 76, use white ink mixed with glass beads.
As described in Japanese Patent Application Laid-Open Publication No. H10-209, the loss of light in the white ink portion is reduced in the case where the addition amount of the white pigment or the fluorescent pigment is reduced as much as possible and the light density ink including the glass beads is used. Occurs, and it is not possible to utilize the total reflection of light on the back surface portion, so that high-luminance light cannot be emitted from the front surface portion.
【０００６】特開平８−２６２４４１号公報に記載され
ているように、導光板の表面部や裏面部に均一な粗面加
工を施したものでは、導光板の表面部から出射する光が
散乱状態となっているため、輝度が低く、プリズムシー
トを使用しない限り照明光の出射方向を制御することが
できない。このため、プリズムシートが余計に必要とな
ってその部品コストが嵩み、平面照明装置全体を薄くす
ることができない。しかも、導光板の表面部や裏面部に
均一な粗面が形成されているため、入射端面部に近い表
面部ほど大量の照明光が出射してしまい、表面部全体に
亙って出射光量を均一にすることが困難である。[0006] As described in Japanese Patent Application Laid-Open No. 8-262441, when a light guide plate is subjected to a uniform roughening process on its front surface and back surface, light emitted from the front surface of the light guide plate is scattered. , The luminance is low and the emission direction of the illumination light cannot be controlled unless a prism sheet is used. For this reason, an additional prism sheet is required, which increases the cost of parts and makes it impossible to make the entire flat lighting device thin. In addition, since a uniform rough surface is formed on the front surface and the back surface of the light guide plate, a larger amount of illumination light is emitted toward the surface portion closer to the incident end surface portion, and the amount of emitted light is reduced over the entire surface portion. It is difficult to make it uniform.
【０００７】特に、モニターディスプレイの如き大型の
液晶表示装置においては、広い視野角も同時に要求され
ており、上述した輝度の高い光を均一に出射させる必要
性とからんでその改善が望まれている。In particular, a large liquid crystal display device such as a monitor display is also required to have a wide viewing angle at the same time, and it is necessary to uniformly emit the above-described high-luminance light, and improvement thereof is desired. .
【０００８】[0008]
【発明の目的】本発明の目的は、表面部から高輝度の光
を広い視野角に亙って均一に出射させることが可能な導
光板およびこの導光板を用いた平面照明装置を提供する
ことにある。SUMMARY OF THE INVENTION It is an object of the present invention to provide a light guide plate capable of uniformly emitting high-intensity light from a surface portion over a wide viewing angle, and a flat lighting device using the light guide plate. It is in.
【０００９】[0009]
【課題を解決するための手段】本発明の第１の形態は、
光源からの光が導入される入射端面部と、この入射端面
部の反対側に位置する反射端面部と、これら入射端面部
および反射端面部を挟んで対向する一対の側端面部と、
前記入射端面部から導入された光を出射する表面部と、
この表面部の反対側に位置する裏面部とを有する導光板
であって、前記一対の側端面部および前記反射端面部に
近接する前記表面部および／または前記裏面部の周縁部
に配される多数の光制御部を具え、これら光制御部は、
曲率半径が２５μm以上の球面の一部にて形成され、前
記表面部および／または前記裏面部からの高さまたは深
さが２μm以下であることを特徴とするものである。According to a first aspect of the present invention, there is provided:
An incident end face where light from the light source is introduced, a reflective end face located opposite to the incident end face, and a pair of side end faces facing each other with the incident end face and the reflective end face interposed therebetween,
A surface portion for emitting light introduced from the incident end surface portion,
A light guide plate having a back surface located on the opposite side of the front surface, the light guide plate being disposed on a peripheral portion of the front surface and / or the back surface close to the pair of side end surfaces and the reflection end surface. It comprises a number of light controls, these light controls
It is characterized by being formed of a part of a spherical surface having a radius of curvature of 25 μm or more, and having a height or depth from the front surface portion and / or the back surface portion of 2 μm or less.
【００１０】本発明によると、光源からの光が入射端面
部から導光板内に入射し、その表面部と裏面部との間お
よび一対の側端面部との間で全反射を繰り返しながら導
光板の反射端面部側へと伝播するが、一対の側端面部お
よび反射端面部に近接する表面部および／または裏面部
の周縁部に配された光制御部に導光板内を伝搬する光が
入射すると、その反射角が変わって一部の光の全反射条
件が破られ、最終的に導光板の外に出射する。各光制御
部は、表面部からの出射光量が相対的に少なくなる傾向
にある一対の側端面部および反射端面部に近接する表面
部および／または裏面部の周縁部に形成されており、表
面部からの出射光量がその全域に亙って均一化される。
また、表面部および／または裏面部に対する光制御部の
傾斜がゆるやかであり、表面部とここから出射する光と
のなす角は比較的小さく、表面部全域から広い角度で出
射する。According to the present invention, the light from the light source enters the light guide plate from the incident end face, and the light guide plate repeats total reflection between the front surface and the back surface and between the pair of side end surfaces. The light propagating in the light guide plate is incident on the light control unit disposed on the peripheral portion of the front and / or rear surface portions adjacent to the pair of side end surfaces and the reflection end surface. Then, the reflection angle is changed, and the condition of the total reflection of some light is broken, and finally, the light is emitted out of the light guide plate. Each light control unit is formed on a peripheral portion of a front surface portion and / or a back surface portion close to a pair of side end surfaces and a reflection end surface where the amount of light emitted from the front surface tends to be relatively small. The amount of light emitted from the portion is made uniform over the entire area.
In addition, the inclination of the light control unit with respect to the front surface portion and / or the rear surface portion is gentle, the angle between the front surface portion and light emitted from the light control portion is relatively small, and light is emitted from the entire surface portion at a wide angle.
【００１１】なお、表面部および／または裏面部からの
光制御部の高さまたは深さが２μmを超えると、この制
御部によって表面部とここから出射する光とのなす角が
大きくなり、視野角が狭くなって本発明の効果を得るこ
とができなくなる。When the height or the depth of the light control unit from the front surface and / or the back surface exceeds 2 μm, the angle between the front surface and the light emitted from the light control unit becomes large by this control unit, and the field of view becomes large. The angle becomes narrow, and the effect of the present invention cannot be obtained.
【００１２】本発明の第２の形態は、光源からの光が導
入される入射端面部と、この入射端面部の反対側に位置
する反射端面部と、これら入射端面部および反射端面部
を挟んで対向する一対の側端面部と、前記入射端面部か
ら導入された光を出射する表面部と、この表面部の反対
側に位置する裏面部とを有する導光板と、この導光板の
前記入射端面部に向けて照明光を投射する光源と、前記
導光板の前記表面部および前記入射端面部以外の部分を
覆う光反射シートとを具えた平面照明装置であって、前
記導光板の前記一対の側端面部および前記反射端面部に
近接する前記表面部および／または前記裏面部の周縁部
に配される多数の光制御部を具え、これら光制御部は、
曲率半径が２５μm以上の球面の一部にて形成され、前
記表面部および／または前記裏面部からの高さまたは深
さが２μm以下であることを特徴とするものである。According to a second aspect of the present invention, an incident end face into which light from a light source is introduced, a reflective end face opposite to the incident end face, and the incident end face and the reflective end face sandwiched therebetween. A light guide plate having a pair of side end surfaces facing each other, a surface portion for emitting light introduced from the incident end surface portion, and a back surface portion opposite to the front surface portion; A flat lighting device comprising: a light source that projects illumination light toward an end surface portion; and a light reflecting sheet that covers a portion of the light guide plate other than the front surface portion and the incident end face portion, wherein the pair of light guide plates is provided. A plurality of light control units disposed on the peripheral portion of the front surface portion and / or the rear surface portion adjacent to the side end surface portion and the reflection end surface portion of the light control portion,
It is characterized by being formed of a part of a spherical surface having a radius of curvature of 25 μm or more, and having a height or depth from the front surface portion and / or the back surface portion of 2 μm or less.
【００１３】本発明によると、入射端面部から導光板内
に入射した照明光の一部は、導光板の表面部および裏面
部で全反射を繰り返しつつ導光板内を伝播するが、一対
の側端面部および反射端面部に近接する表面部および／
または裏面部の周縁部に配された光制御部に導光板内を
伝搬する光が入射すると、その反射角が変わって一部の
光の全反射条件が破られる。そして、導光板の裏面部か
らその外側に出射した照明光は、光反射シートにより乱
反射して再び導光板の裏面部からその内部に入射し、最
終的に導光板の表面部から導光板の外側にすべて出射す
る。この場合、各光制御部は、表面部からの出射光量が
相対的に少なくなる傾向にある一対の側端面部および反
射端面部に近接する表面部および／または裏面部の周縁
部に形成されており、表面部からの出射光量がその全域
に亙って均一化される。また、表面部および／または裏
面部に対する光制御部の傾斜がゆるやかであり、表面部
とここから出射する光とのなす角は比較的小さく、表面
部全域から広い角度で出射することとなる。According to the present invention, a part of the illumination light incident on the light guide plate from the incident end face portion propagates in the light guide plate while repeating total reflection on the front surface portion and the back surface portion of the light guide plate. A surface part close to the end face part and the reflection end face part and / or
Alternatively, when light propagating in the light guide plate is incident on the light control unit disposed on the periphery of the back surface, the reflection angle is changed, and the condition of total reflection of some light is broken. Then, the illumination light emitted from the back surface of the light guide plate to the outside thereof is irregularly reflected by the light reflection sheet, enters again into the inside of the light guide plate from the back surface, and finally from the front surface of the light guide plate to the outside of the light guide plate. Out all. In this case, each light control unit is formed on a peripheral portion of the front surface portion and / or the back surface portion which is close to the pair of side end surfaces and the reflection end surface where the amount of light emitted from the front surface tends to be relatively small. Thus, the amount of light emitted from the surface portion is made uniform over the entire area. In addition, the inclination of the light control unit with respect to the front surface portion and / or the rear surface portion is gentle, the angle between the front surface portion and light emitted from the light control portion is relatively small, and light is emitted from the entire surface portion at a wide angle.
【００１４】[0014]
【発明の実施の形態】本発明の第１の形態による導光板
および本発明の第２の形態による平面照明装置におい
て、光制御部を表面部および／または裏面部の中央部に
対して一対の側端面部および反射端面部側ほど高密度に
配してもよく、入射端面部に対して反射端面部側ほど高
密度に配してもよい。これによって、表面部からの出射
光量がその全域に亙ってより一層均一化される。DESCRIPTION OF THE PREFERRED EMBODIMENTS In a light guide plate according to a first embodiment of the present invention and a flat lighting device according to a second embodiment of the present invention, a light control unit is provided with a pair of central portions of a front surface portion and / or a rear surface portion. The side end face and the reflection end face may be arranged at a higher density on the side of the reflection end face, and the incidence end face may be arranged at a higher density on the side of the reflection end face. As a result, the amount of light emitted from the surface portion is made more uniform over the entire area.
【００１５】また、個々の光制御部が７×１０-8cm2以
上の面積を有してもよく、これによって乱反射を回避し
て高輝度の光が表面部から出射する。Further, each light control section may have an area of 7 × 10 −8 cm 2 or more, whereby high-brightness light is emitted from the surface while avoiding irregular reflection.
【００１６】[0016]
【実施例】本発明を透過型液晶ディスプレイのバックラ
イト光源として応用した実施例について、図１〜図６を
参照しながら詳細に説明するが、本発明はこのような実
施例に限らず、これらをさらに組み合わせたり、この明
細書の特許請求の範囲に記載された本発明の概念に包含
されるべき他の技術にも応用することができる。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied as a backlight source of a transmission type liquid crystal display will be described in detail with reference to FIGS. 1 to 6, but the present invention is not limited to such an embodiment, and Can be further combined or applied to other techniques that are to be encompassed by the inventive concept described in the claims herein.
【００１７】本発明の一実施例による平面照明装置の分
解状態の外観を図１に示し、その導光板の表面部の外観
を図２に示し、表面部の一部の拡大断面構造を図３に示
す。すなわち、本実施例における平面照明装置１１は、
矩形の板状をなす透明な導光板１２と、この導光板１２
の入射端面部１３に沿って配置される光源１４と、導光
板１２の入射端面部１３および表面部１５以外の部分を
覆う光反射シート１６とを有する。また、冷陰極管や複
数のＬＥＤあるいは半導体レーザーにて構成される光源
１４は、反射面が凹曲面となったリフレクタ１７で囲ま
れており、この光源１４からの光は、リフレクタ１７か
らの反射光と共に導光板１２の入射端面部１３から導光
板１２内に入射するようになっている。FIG. 1 shows an appearance of a flat illumination device according to an embodiment of the present invention in an exploded state, FIG. 2 shows an appearance of a surface portion of the light guide plate, and FIG. Shown in That is, the flat lighting device 11 in the present embodiment includes:
A transparent light guide plate 12 having a rectangular plate shape;
And a light reflecting sheet 16 that covers portions of the light guide plate 12 other than the incident end surface 13 and the surface 15. The light source 14 composed of a cold cathode tube, a plurality of LEDs or semiconductor lasers is surrounded by a reflector 17 having a concave reflecting surface, and the light from the light source 14 is reflected by the reflector 17. The light enters the light guide plate 12 from the incident end face 13 of the light guide plate 12 together with the light.
【００１８】光反射シート１６は、導光板１２の反射端
面部１８と一対の側端面部１９と裏面部２０とを覆い、
これらから導光板１２の外側に出射する光を再び導光板
１２内に反射させて導光板１２の表面部１５から出射さ
せるためのものであり、非導電性のフィルムなどにアル
ミニウムなどの金属蒸着したものや金属フィルムを貼付
したもの、あるいはチタン酸バリウムなどを混入または
コートした樹脂などを使用することができ、さらにこれ
らフィルムや樹脂の表面に微細な凸凹加工を施すことが
好ましい。The light reflecting sheet 16 covers the reflecting end face 18, the pair of side end faces 19, and the back face 20 of the light guide plate 12.
The light emitted from these components to the outside of the light guide plate 12 is reflected back into the light guide plate 12 and emitted from the surface portion 15 of the light guide plate 12, and metal such as aluminum is deposited on a non-conductive film or the like. It is possible to use a resin or a resin to which a metal film is attached, or a resin mixed or coated with barium titanate or the like, and it is preferable to subject the surface of the film or resin to fine unevenness.
【００１９】リフレクタ１７は、白色の絶縁性材料やア
ルミニウムなどの金属を蒸着したシート状のものからな
り、導光板１２の入射端面部１３と光源１４とを包囲し
ている。The reflector 17 is made of a sheet in which a white insulating material or a metal such as aluminum is vapor-deposited, and surrounds the light incident surface 13 of the light guide plate 12 and the light source 14.
【００２０】本実施例における導光板１２は、屈折率が
１.４９の透明なアクリル樹脂（ＰＭＭＡ）にて形成さ
れ、光源１４からの光を導入するための入射端面部１３
と、この入射端面部１３の反対側に位置する反射端面部
１８と、これら入射端面部１３および反射端面部１８の
両側端に接続する一対の側端面部１９と、これら入射端
面部１３および反射端面部１８および側端面部１９で囲
まれて入射端面部１３から入射した光を出射させるため
の表面部１５およびその反対側の裏面部２０とを有す
る。表面部１５の反対側に位置する裏面部２０は、表面
部１５と裏面部２０との間隔が入射端面部１３側に対し
て反射端面部１８側ほど狭くなるように、表面部１５に
対して０.５度から１度程度傾斜したテーパ状となって
いる。The light guide plate 12 according to the present embodiment is formed of a transparent acrylic resin (PMMA) having a refractive index of 1.49, and an incident end face portion 13 for introducing light from a light source 14.
A reflection end face 18 located on the opposite side of the incident end face 13; a pair of side end faces 19 connected to both ends of the incident end face 13 and the reflection end face 18; It has a front surface portion 15 for emitting light incident from the incident end surface portion 13 surrounded by the end surface portion 18 and the side end surface portion 19, and a back surface portion 20 on the opposite side. The back surface portion 20 located on the opposite side of the front surface portion 15 is positioned on the front surface portion 15 such that the distance between the front surface portion 15 and the back surface portion 20 becomes smaller toward the reflection end surface portion 18 side than the incident end surface portion 13 side. It has a tapered shape inclined from 0.5 degrees to about 1 degree.
【００２１】本実施例では導光板１２としてアクリル樹
脂を採用したが、光学的に透明な他の材料、例えば屈折
率が１.５０のポリカーボネート（ＰＣ）などを採用す
ることも当然可能である。また、裏面部２０が表面部１
５と平行に形成された導光板を使用するようにしてもよ
い。In this embodiment, an acrylic resin is used as the light guide plate 12, but it is naturally possible to use another optically transparent material, for example, polycarbonate (PC) having a refractive index of 1.50. Also, the back surface 20 is the front surface 1
A light guide plate formed in parallel with 5 may be used.
【００２２】導光板１２の一対の側端面部１９および反
射端面部１８に近接する表面部１５の周縁部には、多数
の光制御部２１が配されており、本実施例における個々
の光制御部２１は、例えば曲率半径ｒが５０μmの凸球
面の一部で形成され、表面部１５から突出するその高さ
ｈは１μmであり、従って、個々の光制御部２１は、お
よそ１５.６７×１０-8cm2の面積をそれぞれ有する。A large number of light control sections 21 are arranged on the periphery of the surface section 15 adjacent to the pair of side end faces 19 and the reflection end face 18 of the light guide plate 12. The part 21 is formed, for example, by a part of a convex spherical surface having a radius of curvature r of 50 μm, and its height h protruding from the surface part 15 is 1 μm. Therefore, the individual light control parts 21 are approximately 15.67 × Each has an area of 10 −8 cm 2 .
【００２３】図２中のIV−IV矢視部およびＶ−Ｖ矢視部
に沿った表面部１５に対する光制御部２１の面積比（密
度）を図４および図５にそれぞれ示すように、光制御部
２１は、表面部１５の中央部に対して一対の側端面部１
９および反射端面部１８側ほど高密度に配されており、
しかも入射端面部１３に対して反射端面部１８側ほど高
密度に配されている。これによって、出射光量が相対的
に少なくなる傾向にあるこれらの領域の出射光量を増大
させている。As shown in FIGS. 4 and 5, the area ratio (density) of the light control section 21 to the surface section 15 along the line IV-IV and the line VV in FIG. The control unit 21 is configured such that the pair of side end surfaces 1
9 and the reflection end face portion 18 side are arranged with high density,
In addition, the closer to the reflection end face portion 18 with respect to the incidence end face portion 13, the higher the density. As a result, the amount of emitted light in these regions where the amount of emitted light tends to be relatively small is increased.
【００２４】つまり、入射端面部１３から導光板１２内
に入射した光は、０≦｜γ｜≦sin- 1（１／ｎ）を満た
す屈折角γ（例えば、０°〜±４２°）で導光板１２内
を伝播し、特に臨界角近傍の光Ｌが光制御部２１に入射
すると、その反射角が変わって一部の光の全反射条件が
破られ、最終的に導光板１２の外に出射する。各光制御
部２１は、一対の側端面部１９および反射端面部１８に
近接する表面部１５の周縁部に形成されているため、表
面部１５からの出射光量がその全域に亙って均一化され
る。本実施例では、特に一対の側端面部１９および反射
端面部１８側ほどその密度を高く設定しているため、表
面部１５からの出射光量をより一層均一化させることが
できる。また、表面部１５に対する光制御部２１の傾斜
が比較的ゆるやかであり、表面部１５とここから出射す
る光線Ｌとのなす角θが比較的小さくなるため、表面部
１５からの出射光Ｌは、その全域から広い角度で出射す
ることとなり、高輝度かつ広角度の照明光を得ることが
できる。That is, the light incident on the light guide plate 12 from the incident end face 13 has a refraction angle γ (for example, 0 ° to ± 42 °) satisfying 0 ≦ | γ | ≦ sin - 1 (1 / n). When light L propagating in the light guide plate 12 and particularly near the critical angle enters the light control unit 21, its reflection angle changes and the condition for total reflection of some light is violated. Out. Each of the light control sections 21 is formed on the peripheral edge of the surface section 15 adjacent to the pair of side end face sections 19 and the reflection end face section 18, so that the amount of light emitted from the surface section 15 is uniform over the entire area. Is done. In this embodiment, in particular, the density is set higher on the pair of side end face portions 19 and the reflection end face portion 18 side, so that the amount of light emitted from the surface portion 15 can be made more uniform. Further, since the inclination of the light control unit 21 with respect to the surface unit 15 is relatively gentle, and the angle θ between the surface unit 15 and the light beam L emitted therefrom is relatively small, the light L emitted from the surface unit 15 is The light is emitted from the entire area at a wide angle, and high-brightness and wide-angle illumination light can be obtained.
【００２５】個々の光制御部２１の面積は、７×１０-8
cm2以上であることが必要であり、これより小さくなる
と、梨地加工と同じような状態となって光制御部２１に
よる乱反射が大きくなり、表面部１５から高輝度の光Ｌ
を出射させることが困難になる。The area of each light control unit 21 is 7 × 10 -8
It is necessary cm 2 or more, becomes smaller than this, irregular reflection by the light control section 21 becomes similar state as satin finish is increased, the surface portion 15 of the high-brightness light L
Is difficult to emit.
【００２６】本実施例では、表面部１５からの光制御部
２１の突出高さｈを１μmとしたので、その面積が７×
１０-8cm2以上となるように、光制御部２１の曲率半径
を５０μmに設定したが、例えば光制御部２１の曲率半
径を２５μmに設定した場合には、その面積を７×１０
-8cm2以上とするために表面部１５からの突出高さｈを
およそ２μmにする必要がある。しかしながら、表面部
１５に対する光制御部２１の突出高さｈが２μmを超え
ると、表面部１５に対する光制御部２１の傾斜が大きく
なってしまい、ここから出射する光Ｌと表面部１５との
なす角θが大きくなって照明光を広角化することが困難
となるので、表面部１５からの突出高さｈは２μm以下
である必要がある。In this embodiment, since the height h of the light control section 21 protruding from the surface section 15 is set to 1 μm, the area is 7 ×.
Although the radius of curvature of the light control unit 21 is set to 50 μm so as to be 10 −8 cm 2 or more, for example, when the radius of curvature of the light control unit 21 is set to 25 μm, the area is 7 × 10
In order to attain -8 cm 2 or more, it is necessary to make the protruding height h from the surface portion 15 approximately 2 μm. However, when the projection height h of the light control unit 21 with respect to the surface unit 15 exceeds 2 μm, the inclination of the light control unit 21 with respect to the surface unit 15 becomes large, and the light L emitted from the light control unit 21 and the surface unit 15 form. Since the angle θ becomes large and it becomes difficult to widen the illumination light, the height h of the projection from the surface portion 15 needs to be 2 μm or less.
【００２７】上述した実施例では、光制御部２１を導光
板１２の表面部１５から突出させるようにしたが、これ
らの曲率中心を導光板１２の外側に設定し、光制御部２
１が表面部１５から凹むような形状とするようにしても
よい。また、裏面部２０側に光制御部２１を形成するこ
とも可能であり、これを表面部１５および裏面部２０共
に形成するようにしてもよい。In the above-described embodiment, the light control unit 21 is made to protrude from the surface 15 of the light guide plate 12, but the center of curvature is set outside the light guide plate 12, and the light control unit 2
1 may be formed so as to be recessed from the surface portion 15. Further, the light control unit 21 can be formed on the back surface 20 side, and the light control unit 21 may be formed on both the front surface unit 15 and the back surface unit 20.
【００２８】また、ＦＣＬを用いた光源１４の長手方向
両端部においては、その光量が長手方向中央部よりも低
下するのが普通であるから、入射端面部１３の長手方向
両端部に近接する表面部１５および／または裏面部２０
の周縁部に光制御部２１をさらに形成することも有効で
ある。In addition, since the amount of light at the both ends in the longitudinal direction of the light source 14 using the FCL is generally lower than that at the central part in the longitudinal direction, the surface close to the both ends in the longitudinal direction of the incident end face 13 is used. Part 15 and / or back part 20
It is also effective to further form the light control section 21 on the peripheral portion of the light emitting element.
【００２９】このような本発明による導光板１２の他の
実施例における表面部１５の外観を図６に示すが、先の
実施例と同一機能の部分には、これと同一符号を記して
重複する説明は省略するものとする。すなわち、本実施
例では、入射端面部１３の長手方向両端部に近接する表
面部１５の周縁部に光制御部２１をさらに形成すること
により、光源１４としてＦＣＬを用いた場合でも照明光
を表面部１５から均一に出射させることができる。FIG. 6 shows the appearance of the surface portion 15 in another embodiment of the light guide plate 12 according to the present invention. Parts having the same functions as those in the previous embodiment are denoted by the same reference numerals and are repeated. The description of the operation will be omitted. That is, in the present embodiment, the light control unit 21 is further formed on the periphery of the surface unit 15 close to both ends in the longitudinal direction of the incident end surface unit 13, so that the illumination light can be emitted even when FCL is used as the light source 14. The light can be uniformly emitted from the portion 15.
【００３０】[0030]
【発明の効果】本発明によると、導光板の表面部および
／または裏面部からの高さまたは深さが２μm以下であ
って、曲率半径が２５μm以上の球面の一部にて形成さ
れた多数の光制御部を、導光板の一対の側端面部および
反射端面部に近接する表面部および／または裏面部の周
縁部にのみ配したので、面積の大きな導光板であって
も、その表面部全域から広い角度で高輝度の光を均一に
出射させることができる。According to the present invention, the light guide plate has a height or depth from the front surface and / or the back surface of 2 μm or less and a radius of curvature of 25 μm or more. Is disposed only on the peripheral portion of the front surface portion and / or the rear surface portion adjacent to the pair of side end surfaces and the reflection end surface of the light guide plate, so that even if the light guide plate has a large area, High-luminance light can be uniformly emitted from the entire region at a wide angle.
【００３１】また、光制御部を表面部および／または裏
面部の中央部に対して一対の側端面部および反射端面部
側ほど高密度に配したり、あるいは入射端面部に対して
反射端面部側ほど高密度に配した場合には、導光板の表
面部から出射する光をより一層均一化させることができ
る。The light control section may be arranged at a higher density on the pair of side end faces and the reflection end face with respect to the center of the front and / or rear faces, or may be provided with the reflection end face with respect to the incident end face. In the case where the light guide plate is arranged at a higher density, the light emitted from the surface of the light guide plate can be made more uniform.
【００３２】個々の光制御部が７×１０-8cm2以上の面
積を有するようにした場合には、光制御部による光の乱
反射が回避され、より一層高輝度の光を表面部から出射
させることができる。When each light control section has an area of 7 × 10 −8 cm 2 or more, irregular reflection of light by the light control section is avoided, and light with higher luminance is emitted from the surface section. Can be done.
【図１】本発明による平面照明装置の一実施例の概略構
造を表す分解斜視図である。FIG. 1 is an exploded perspective view illustrating a schematic structure of an embodiment of a flat lighting device according to the present invention.
【図２】図１に示した実施例における導光板の表面部の
平面図である。FIG. 2 is a plan view of a surface portion of a light guide plate in the embodiment shown in FIG.
【図３】図１に示した実施例における光制御部の構造を
表す断面図である。FIG. 3 is a cross-sectional view illustrating a structure of a light control unit in the embodiment shown in FIG.
【図４】図２中のIV−IV矢視に沿った光制御部の分布密
度を表すグラフである。FIG. 4 is a graph showing the distribution density of the light control unit along the line IV-IV in FIG.
【図５】図２中のＶ−Ｖ矢視に沿った光制御部の分布密
度を表すグラフである。FIG. 5 is a graph showing a distribution density of the light control unit along a line VV in FIG. 2;
【図６】本発明による導光板の他の実施例における表面
部の平面図である。FIG. 6 is a plan view of a surface portion of a light guide plate according to another embodiment of the present invention.
１１ 平面照明装置 １２ 導光板 １３ 入射端面部 １４ 光源 １５ 表面部 １６ 光反射シート １７ リフレクタ １８ 反射端面部 １９ 側端面部 ２０ 裏面部 ２１ 光制御部 Ｌ 光 ｒ 光制御部の曲率半径 ｈ 表面部からの光制御部の高さ θ 表面部と出射光とのなす角 DESCRIPTION OF SYMBOLS 11 Planar illumination device 12 Light guide plate 13 Incident end face part 14 Light source 15 Surface part 16 Light reflection sheet 17 Reflector 18 Reflection end face part 19 Side end face part 20 Back part 21 Light control part L light r Curvature radius of light control part h From surface part Height of the light control part θ Angle between the surface part and the emitted light
───────────────────────────────────────────────────── フロントページの続き (72)発明者 遠藤 司 東京都多摩市永山６−22−６ 日本デンヨ ー株式会社内 Ｆターム(参考） 2H038 AA55 BA06 2H091 FA14Z FA23Z LA18 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tsukasa Endo 6-22-6 Nagayama, Tama-shi, Tokyo F-term (reference) in Denyo Corporation 2H038 AA55 BA06 2H091 FA14Z FA23Z LA18
Claims (8)
と、この入射端面部の反対側に位置する反射端面部と、
これら入射端面部および反射端面部を挟んで対向する一
対の側端面部と、前記入射端面部から導入された光を出
射する表面部と、この表面部の反対側に位置する裏面部
とを有する導光板であって、 前記一対の側端面部および前記反射端面部に近接する前
記表面部および／または前記裏面部の周縁部に配される
多数の光制御部を具え、これら光制御部は、曲率半径が
２５μm以上の球面の一部にて形成され、前記表面部お
よび／または前記裏面部からの高さまたは深さが２μm
以下であることを特徴とする導光板。1. An incident end face to which light from a light source is introduced, a reflective end face opposite to the incident end face,
It has a pair of side end surfaces facing each other with the incident end surface portion and the reflection end surface portion interposed therebetween, a surface portion for emitting light introduced from the incident end surface portion, and a back surface portion located on the opposite side of the front surface portion. A light guide plate, comprising: a plurality of light control units disposed on a peripheral portion of the front surface portion and / or the back surface portion adjacent to the pair of side end surfaces and the reflection end surface; It is formed by a part of a spherical surface having a radius of curvature of 25 μm or more, and has a height or a depth of 2 μm from the front surface portion and / or the rear surface portion.
A light guide plate characterized by the following.
たは前記裏面部の中央部に対して前記一対の側端面部お
よび前記反射端面部側ほど高密度に配されていることを
特徴とする請求項１に記載の導光板。2. The light control unit according to claim 1, wherein the pair of side end surfaces and the reflection end surface are arranged at a higher density with respect to a central portion of the front surface portion and / or the rear surface portion. The light guide plate according to claim 1.
て前記反射端面部側ほど高密度に配されていることを特
徴とする請求項１または請求項２に記載の導光板。3. The light guide plate according to claim 1, wherein the light control section is arranged at a higher density with respect to the incident end face toward the reflection end face.
以上の面積を有することを特徴とする請求項１から請求
項３の何れかに記載の導光板。4. The light control unit according to claim 1, wherein each of the light control units is 7 × 10 −8 cm 2.
The light guide plate according to any one of claims 1 to 3, wherein the light guide plate has the above area.
と、この入射端面部の反対側に位置する反射端面部と、
これら入射端面部および反射端面部を挟んで対向する一
対の側端面部と、前記入射端面部から導入された光を出
射する表面部と、この表面部の反対側に位置する裏面部
とを有する導光板と、 この導光板の前記入射端面部に向けて照明光を投射する
光源と、 前記導光板の前記表面部および前記入射端面部以外の部
分を覆う光反射シートと を具えた平面照明装置であって、前記導光板の前記一対
の側端面部および前記反射端面部に近接する前記表面部
および／または前記裏面部の周縁部に配される多数の光
制御部を具え、これら光制御部は、曲率半径が２５μm
以上の球面の一部にて形成され、前記表面部および／ま
たは前記裏面部からの高さまたは深さが２μm以下であ
ることを特徴とする平面照明装置。5. An incident end face to which light from a light source is introduced, a reflecting end face opposite to the incident end face,
It has a pair of side end surfaces facing each other with the incident end surface portion and the reflection end surface portion interposed therebetween, a surface portion for emitting light introduced from the incident end surface portion, and a back surface portion located on the opposite side of the front surface portion. A planar lighting device comprising: a light guide plate; a light source that projects illumination light toward the incident end surface of the light guide plate; and a light reflection sheet that covers a part other than the surface portion and the incident end surface of the light guide plate. And a plurality of light control units disposed on a peripheral portion of the front surface portion and / or the rear surface portion adjacent to the pair of side end surfaces and the reflection end surface of the light guide plate, and these light control units are provided. Has a radius of curvature of 25 μm
A flat lighting device formed by a part of the spherical surface and having a height or a depth from the front surface portion and / or the rear surface portion of 2 μm or less.
たは前記裏面部の中央部に対して前記一対の側端面部お
よび前記反射端面部側ほど高密度に配されていることを
特徴とする請求項５に記載の平面照明装置。6. The light control section is arranged at a higher density with respect to the central part of the front surface part and / or the rear surface part as the pair of side end face parts and the reflection end face part side. The flat lighting device according to claim 5, wherein
て前記反射端面部側ほど高密度に配されていることを特
徴とする請求項５または請求項６に記載の平面照明装
置。7. The flat lighting device according to claim 5, wherein the light control section is arranged at a higher density with respect to the incident end face section toward the reflection end face section.
以上の面積を有することを特徴とする請求項５から請求
項７の何れかに記載の平面照明装置。8. Each of the light control units has a size of 7 × 10 −8 cm 2.
The flat lighting device according to any one of claims 5 to 7, wherein the flat lighting device has the area described above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30425999A JP2001126521A (en) | 1999-10-26 | 1999-10-26 | Light guide plate and plane illuminating device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30425999A JP2001126521A (en) | 1999-10-26 | 1999-10-26 | Light guide plate and plane illuminating device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001126521A true JP2001126521A (en) | 2001-05-11 |
Family
ID=17930911
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30425999A Pending JP2001126521A (en) | 1999-10-26 | 1999-10-26 | Light guide plate and plane illuminating device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001126521A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012108509A (en) * | 2010-11-17 | 2012-06-07 | Samsung Electronics Co Ltd | Display device and driving method for the same |
| US11269132B1 (en) * | 2021-04-26 | 2022-03-08 | Dell Products L.P. | Display panel bottom side border |
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| JPH0461302U (en) * | 1990-10-03 | 1992-05-26 | ||
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2012108509A (en) * | 2010-11-17 | 2012-06-07 | Samsung Electronics Co Ltd | Display device and driving method for the same |
| US9412313B2 (en) | 2010-11-17 | 2016-08-09 | Samsung Display Co., Ltd. | Display apparatus and method of driving the same |
| KR101761884B1 (en) * | 2010-11-17 | 2017-08-07 | 삼성디스플레이 주식회사 | Display apparatus and method of driving the same |
| US11269132B1 (en) * | 2021-04-26 | 2022-03-08 | Dell Products L.P. | Display panel bottom side border |
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