JPH07270617A - Light guide plate and plane illuminating device using the same - Google Patents
Light guide plate and plane illuminating device using the sameInfo
- Publication number
- JPH07270617A JPH07270617A JP7021981A JP2198195A JPH07270617A JP H07270617 A JPH07270617 A JP H07270617A JP 7021981 A JP7021981 A JP 7021981A JP 2198195 A JP2198195 A JP 2198195A JP H07270617 A JPH07270617 A JP H07270617A
- Authority
- JP
- Japan
- Prior art keywords
- guide plate
- light guide
- light
- light source
- curve
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はパーソナルコンピュータ
ーやワードプロセッサー、電話器などの液晶表示装置に
おけるバックライトとして用いられる平面照光装置の導
光板に関する。また、この照光装置を用いた液晶画像表
示装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate for a flat illumination device used as a backlight in a liquid crystal display device such as a personal computer, a word processor and a telephone. Further, the present invention relates to a liquid crystal image display device using this illumination device.
【０００２】[0002]
【従来の技術】通称エッジライトと呼ばれる側方光源型
平面照光装置は、透明導光板の裏面に光反射面を持ち、
導光板のどちらかの面に出射光の均一化を図るための調
光パターンが施されている。これは導光板裏面の表面形
状が均一であると光源に近いところの出射面が明るく、
遠くなるに従い暗くなると言う輝度ムラが生じるのを解
消するためである。調光パターンとして最も代表的なも
のは図６に示すようなもので、透明導光板の裏面に大き
さの異なる複数円形乱反射面からなる調光パターンが設
けられ、それによって光源Ｌから遠ざかるに従い反射光
すなわち導光板の表面から射出される光量を多くする様
になっている。他に、導光板裏面に凹部または凸部を設
け、その深さまたは高さを順次大きくするもの（特開平
５−２２４０１９、実開平５−６９７８２）、プリズム
面を反射面とし、出射面（導光板表面）に通常パターン
の半透過グラデーション印刷部を設けた調光パターン
（実開平５−７３６２８）などが知られている。2. Description of the Related Art A side light source type flat illumination device, which is commonly called an edge light, has a light reflecting surface on the back surface of a transparent light guide plate.
A dimming pattern is provided on either surface of the light guide plate to make the emitted light uniform. This is because if the surface shape of the back surface of the light guide plate is uniform, the emission surface near the light source is bright,
The reason for this is to eliminate the occurrence of uneven brightness that the image becomes darker as the distance increases. The most typical dimming pattern is as shown in FIG. 6, in which a transparent dimming plate is provided with a dimming pattern made up of a plurality of circular irregular reflection surfaces of different sizes, whereby the light is reflected away from the light source L. The amount of light, that is, the amount of light emitted from the surface of the light guide plate is increased. In addition, a concave portion or a convex portion is provided on the back surface of the light guide plate, and the depth or height of the concave portion is sequentially increased (Japanese Patent Laid-Open No. 5-224019 and Japanese Utility Model Laid-Open No. 5-69782). There is known a dimming pattern (actual Kaihei 5-73628) in which a semi-transparent gradation printing portion of a normal pattern is provided on the light plate surface).
【０００３】[0003]
【発明が解決しようとする課題】導光板面に凹部または
凸部を設け、これの密度や大きさ等を徐々に変化させ入
射する光に対する反射・拡散度合いをコントロールし均
一出射するための設計は難しく、また製造も難しい。ド
ットグラデーション印刷（図６）による入射光のコント
ロールを利用した方式では、設計・製造は比較的容易だ
が製造工程が成形と印刷の２工程になる上、充分な輝度
が得られないという欠点がある。本発明は、このような
従来技術の課題を解決するために導光板出射面を輝度ム
ラ無く均一に、且つ輝度が最大限となるようにし、さら
に設計と製法が容易な導光板を提供し、かつこれを用い
た平面照光装置及びこれを利用した液晶画像表示装置を
提供するものである。A design for providing concave portions or convex portions on the light guide plate surface and gradually changing the density, size, etc. of the concave portions or convex portions to control the degree of reflection / diffusion of incident light and to uniformly emit the light is known. Difficult and difficult to manufacture. The method using the control of incident light by dot gradation printing (Fig. 6) is relatively easy to design and manufacture, but has the disadvantage that the manufacturing process consists of molding and printing, and sufficient brightness cannot be obtained. . The present invention, in order to solve the problems of the prior art such that the light guide plate exit surface is uniform without brightness unevenness, and the brightness is maximized, and further provides a light guide plate that is easy to design and manufacture, The present invention also provides a flat illumination device using the same and a liquid crystal image display device using the same.
【０００４】[0004]
【課題を解決するための手段】本発明は、透明導光板の
側面部に光源を配置した側方光源型平面照光装置におい
て、該導光板の裏面には断面が凹部もしくは凸部で構成
されたあるいは印刷によって構成された複数曲線からな
る調光パターンが設けられ、該調光パターンの各曲線
が、前記導光板の側面部領域においては該光源側側面部
とほぼ垂直であるが、該側面部に対向する他端面部にお
いてはほぼ平行であることを特徴とする導光板の構成に
よって前述課題を解決するものである。また本発明は、
透明導光板の一側面部に光源を配置した側方光源型平面
照光装置において、該導光板の裏面には断面が凹部もし
くは凸部で構成されたあるいは印刷によって構成された
複数曲線からなる調光パターンが設けられ、該調光パタ
ーンが、円の中心点または多次曲線の原点が一直線上又
は円周上を実質的に等間隔にずらして描いた複数の曲線
から構成されることを特徴とする導光板を提供する。According to the present invention, there is provided a lateral light source type planar illuminating device in which a light source is arranged on a side surface of a transparent light guide plate, wherein the back surface of the light guide plate has a concave or convex cross section. Alternatively, a dimming pattern composed of a plurality of curved lines formed by printing is provided, and each curve of the dimming pattern is substantially perpendicular to the light source side surface portion in the side surface region of the light guide plate, The above-mentioned problem is solved by the structure of the light guide plate, which is characterized in that the other end face portion facing to is substantially parallel. Further, the present invention is
In a lateral light source type flat illumination device in which a light source is arranged on one side surface of a transparent light guide plate, a dimming consisting of a plurality of curved lines whose cross section is concave or convex on the back surface of the light guide plate or formed by printing. A dimming pattern is provided, and the dimming pattern is composed of a plurality of curves in which the center point of the circle or the origin of the multi-order curve is drawn on a straight line or on the circumference at substantially equal intervals. A light guide plate is provided.
【０００５】また、本発明は、透明導光板の側面部に光
源を配置し、導光板の裏面に反射面を配置した側方光源
型平面照光装置において、該導光板の裏面には断面が凹
部もしくは凸部で構成されたあるいは印刷によって構成
された複数曲線からなる調光パターンが設けられ、該調
光パターンが、円の中心点または多次曲線の原点が一直
線上又は円周上を実質的に等間隔にずらして描いた複数
の曲線から構成された前記導光板を備えたことを特徴と
する平面照光装置を提供する。また本発明は、（ａ）液
晶表示パネルと、（ｂ）これを裏面から照射するための
導光板の一側面部に光源を配置し、導光板の裏面に反射
面を配置した側方光源型平面照光装置と、（ｃ）該平面
照光装置と前記液晶表示パネルとの間に光拡散板を配置
してなる液晶画像表示装置において、該平面照光装置の
導光板の裏面には断面が凹部もしくは凸部で構成された
あるいは印刷によって構成された複数曲線からなる調光
パターンが設けられ、該調光パターンが、円の中心点ま
たは多次曲線の原点が一直線上又は円周上を実質的に等
間隔にずらして描いた複数の曲線から構成されることを
特徴とする液晶画像表示装置を提供する。Further, according to the present invention, there is provided a lateral light source type flat illumination device in which a light source is arranged on a side surface of a transparent light guide plate and a reflecting surface is arranged on a rear surface of the light guide plate. Alternatively, a dimming pattern composed of a plurality of curves formed of convex portions or formed by printing is provided, and the dimming pattern is such that the center point of the circle or the origin of the multidimensional curve is substantially on a straight line or on the circumference. Provided is a flat illumination device comprising the light guide plate configured by a plurality of curved lines drawn at regular intervals. Further, the present invention relates to (a) a liquid crystal display panel, and (b) a side light source type in which a light source is arranged on one side surface portion of a light guide plate for irradiating the liquid crystal panel from the back surface, and a reflection surface is arranged on the back surface of the light guide plate. In a liquid crystal image display device comprising a flat light illuminating device, and (c) a light diffusing plate disposed between the flat light illuminating device and the liquid crystal display panel. A dimming pattern composed of a plurality of curves formed of convex portions or formed by printing is provided, and the dimming pattern is such that the center point of the circle or the origin of the multi-order curve is substantially on a straight line or on the circumference. Provided is a liquid crystal image display device comprising a plurality of curved lines drawn at equal intervals.
【０００６】本発明の特徴とするところは透明導光板の
裏面に設けられるパターンにあり、該パターンの意図す
るところは、 導光板の有効表示面に対してパターン曲線の曲率、ピ
ッチ、一直線又は円周上に並ぶ中心又は原点との位置関
係を選ぶことにより、パターン形成部分の面積と残る平
面との面積比を光源側からの距離に従う任意の割合で連
続的に粗から密に変化させることにある。また、この
パターンを構成する曲線は単一線状光源又は一直線上に
配列された複数光点より構成される線状光源に対して、
光源近傍ではパターンが形成される平面上に於いて垂直
に近い角度で存在し、光源から距離が離れるに従い平行
に近くなって行く構成を得ることにある。これは、パタ
ーン曲線を構成する凹部または凸部の斜面に同じ密度の
光束が入射した場合、斜面単位面積当たりの光束密度は
光源近傍では小さく光源から離れるに従い高くなってゆ
くことを意味する。また、斜面で反射する光を考察する
と、出射面側から見た場合、光源近傍では斜面に対して
浅い角度で入射することになり反射光は光源から遠い方
に向かって反射して行く成分が多くなるが、一方光源か
ら離れた位置では斜面に対して深い角度（直角に近い角
度）で入射することになりその反射光は直接出射面から
出射される成分（拡散成分）が増えることになる。この
結果光源に近い出射面からの出射量と遠い出射面からの
出射光量を均等化することができる。更に、このパタ
ーンを構成する円曲線又は多次曲線の中心点または原点
は、光源が直線上のときは直線上に並んでいることが好
ましいが、光源がＬ字状であるときは中心点又は原点が
円曲線上に並ぶ様に設計するのがよい。この様にして構
成されたパターン曲線は、光源がＬ字状になっていても
光源近傍では側面部と垂直に近い角度で存在し、光源近
傍での反射率を小さく抑え、照光面上の揮度を均一化す
ることができる。The feature of the present invention resides in the pattern provided on the back surface of the transparent light guide plate, and the intended purpose of the pattern is the curvature, pitch, straight line or circle of the pattern curve with respect to the effective display surface of the light guide plate. By selecting the positional relationship with the center or the origin lined up on the circumference, the area ratio of the area of the pattern formation portion to the remaining plane can be continuously changed from coarse to dense at an arbitrary ratio according to the distance from the light source side. is there. Further, the curve forming this pattern is for a single linear light source or a linear light source composed of a plurality of light spots arranged in a straight line,
In the vicinity of the light source, the pattern exists on the plane where the pattern is formed, at an angle close to vertical, and it becomes to become closer to parallel as the distance from the light source increases. This means that when a light flux of the same density is incident on the slopes of the concave portions or the convex portions that form the pattern curve, the light flux density per unit area of the slope is small near the light source and increases as the distance from the light source increases. Considering the light reflected on the slope, when viewed from the exit surface side, the light will be incident at a shallow angle near the light source in the vicinity of the light source, and the reflected light will have a component reflected away from the light source. On the other hand, on the other hand, at a position distant from the light source, the light is incident on the slope at a deep angle (an angle close to a right angle), and the reflected light has an increased component (diffuse component) directly emitted from the emission surface. . As a result, the amount of light emitted from the emission surface near the light source and the amount of light emitted from the emission surface far from the light source can be equalized. Further, it is preferable that the center points or the origins of the circular curves or the multi-order curves forming this pattern are arranged on a straight line when the light source is on a straight line, but when the light source is L-shaped, the center point or It is good to design so that the origins are lined up on a circular curve. Even if the light source is L-shaped, the pattern curve configured in this manner exists near the light source at an angle nearly perpendicular to the side surface, and suppresses the reflectance in the vicinity of the light source to a small level, thereby reducing the darkness on the illuminated surface. The degree can be made uniform.
【０００７】[0007]
【実施例】以下、図に示す本発明の実施例につき詳しく
説明する。図１に本発明の１実施例としての曲線パター
ンの典型的な例を示す。直線Ｘ線上で所定の一定間隔ｄ
をおいて配置された多数の中心点ｒ1 ，ｒ2 ，ｒ3 ---
を中心に半径Ｒの円を多数描いた場合の曲線パターンが
示されている。このような曲線パターンが上縁Ａ及び下
縁Ｂを有する透明導光板ＬＧ上にも描かれる。すなわち
この導光板ＬＧ上には円曲線ｂ1 ，ｂ2 ，ｂ3 --- とそ
れと逆向きの円曲線ｃ1 ，ｃ2 ，ｃ3 --- とが描かれて
いる。図から明らかなように光源Ｌ側では粗パターンと
なり、下縁Ｂ側では密パターンとなる。しかも、各円曲
線は導光板ＬＧの上縁Ａ付近では光源Ｌに対してほぼ垂
直であり、一方下縁Ｂ付近では光源Ｌに対してほぼ平行
となっている。Embodiments of the present invention shown in the drawings will be described in detail below. FIG. 1 shows a typical example of a curved pattern as one embodiment of the present invention. Predetermined constant interval d on the straight X-ray
A large number of center points r 1 , r 2 , r 3 ---
A curve pattern is shown in the case where a large number of circles with a radius R are drawn centering on. Such a curved pattern is also drawn on the transparent light guide plate LG having the upper edge A and the lower edge B. That is, circular curves b 1 , b 2 , b 3 --- and circular curves c 1 , c 2 , c 3 --- in the opposite direction are drawn on the light guide plate LG. As is clear from the figure, the light source L side has a rough pattern, and the lower edge B side has a dense pattern. Moreover, each circular curve is substantially perpendicular to the light source L near the upper edge A of the light guide plate LG, and is substantially parallel to the light source L near the lower edge B.
【０００８】光源Ｌから発した各光線は、上縁Ａ付近で
は曲線がほぼ光源Ｌとほぼ垂直であるため曲線が構成さ
れる例えばＶ字溝部で反射（乱反射）される割合が少な
いので光拡散効果は少ない。一方、導光板ＬＧの下縁Ｂ
付近では曲線が光源Ｌとほぼ平行であるため、入射光は
Ｖ字溝部に対して深い角度で入射される。従って光反射
が増え光拡散効果は高いものとなる。このように、上縁
Ａから下縁Ｂに向うに従って拡散効果が増大され導光板
全体としては均一な光出射が達成され得る。Each light beam emitted from the light source L has a curved line near the upper edge A and is substantially perpendicular to the light source L, so that the curved line is less likely to be reflected (diffuse reflection) at the V-shaped groove portion. Has little effect. On the other hand, the lower edge B of the light guide plate LG
Since the curved line is substantially parallel to the light source L in the vicinity, the incident light is incident on the V-shaped groove portion at a deep angle. Therefore, the light reflection increases and the light diffusion effect becomes high. In this way, the diffusion effect increases from the upper edge A toward the lower edge B, and uniform light emission can be achieved as the entire light guide plate.
【０００９】ここで用語「ほぼ垂直」及び「ほぼ平行」
とは、“垂直に近い”及び“平行に近い”という程度の
意味であり、分度器で測定するような厳密な精度を表す
意味ではない。透明導光板の用途目的、面積、厚さ、凹
部、凸部の段差の寸法等々種種のファクターに対応し
て、この用語は柔軟に解釈されるべきであり、導光板の
上縁部から下縁部に至るまでのパターンの粗密変化を表
現する一つの手段として用いた用語に過ぎない。従っ
て、“垂直”及び“平行”が夫々２０°〜４０°程度の
角度範囲を有することもあり得ると解されるべきであ
る。円の半径Ｒは照光装置の大きさによって変わるが通
常の２〜８インチ程度の液晶パネル用の導光板の場合に
は約５０〜１２０ｍｍの範囲が好適である。各々の円曲
線の中心間隔ｄは、曲線を切削加工で形成する凹部の深
さまたは凸部の高さ（段差）及び導光距離の長さに依在
して変わるが、中心点（ｒ1 ，ｒ2 ，ｒ3 --- ）が並ぶ
位置におい約０．３〜２．０ｍｍの範囲が好適である。Here, the terms "substantially vertical" and "substantially parallel"
The terms "near vertical" and "near parallel" mean that they do not mean strict accuracy as measured by a protractor. This term should be flexibly interpreted according to various factors such as purpose of use of transparent light guide plate, area, thickness, size of step of concave portion, convex portion, etc. It is just a term used as one means of expressing the variation in the density of the pattern up to the part. Therefore, it should be understood that “vertical” and “parallel” may have an angular range of 20 ° to 40 °, respectively. The radius R of the circle varies depending on the size of the illuminating device, but in the case of a light guide plate for a normal liquid crystal panel of about 2 to 8 inches, a range of about 50 to 120 mm is preferable. The center distance d of each circular curve varies depending on the depth of the concave portion or the height (step) of the convex portion and the length of the light guide distance that form the curve by cutting, but the center point (r 1 , R 2 , r 3 ---) are preferably arranged in a range of about 0.3 to 2.0 mm.
【００１０】図２は円曲線の代わりに２次曲線を用いる
本発明の第２実施例を示す。第１実施例と同様、一直線
Ｘ上に、多数の２次曲線の頂点が所定の距離ｄで配置さ
れている。従って各２次曲線の各原点も一直線上に並ん
でいる。この２次曲線はＹ＝ａＸ2 の係数ａを変える事
により自由自在に曲線形状を変える事が出来るので、円
曲線では輝度均一化の設計がうまく行かない導光板形状
の場合のパターン設計に好適である。図３は光源がＬ字
形状となっている場合に円曲線を用いて調光パターンを
設計した例である。各々の円曲線の中心点は円曲線Ｙ上
に等間隔で並んでいる。導光板の一端縁で粗であり対向
他端縁に向うに従って密となってゆくパターンは、第１
および第２実施例で夫々述べた円又は２次曲線の他に、
３次曲線またはそれ以上の高次曲線でも良い。FIG. 2 shows a second embodiment of the present invention which uses a quadratic curve instead of a circular curve. Similar to the first embodiment, a large number of quadratic curve vertices are arranged on the straight line X at a predetermined distance d. Therefore, the origins of the quadratic curves are also aligned. This quadratic curve can be freely changed in shape by changing the coefficient a of Y = aX 2 , so it is suitable for pattern design in the case of light guide plate shape where circular brightness does not work well for uniform brightness. Is. FIG. 3 is an example of designing a dimming pattern using a circular curve when the light source has an L shape. The center points of the respective circular curves are arranged on the circular curve Y at equal intervals. The pattern that is rough at one end of the light guide plate and becomes denser toward the opposite end is the first pattern.
In addition to the circle or the quadratic curve described in the second embodiment,
A cubic curve or a higher-order curve higher than that may be used.
【００１１】パターンを構成する凹部または凸部の断面
形状は任意で良いが、Ｖ字型、角型、半円球型、多角形
型など種々のものにする事が出来る。何れの場合も金型
を利用して射出成型で容易に製造できる。凹部の場合の
Ｖ字型は切削加工でも製造できるし、反射角度の制御も
行いやすくて好ましい断面形状となる。凹部（溝部）の
深さまたは凸部の高さは約０．０１〜０．５ｍｍが適当
である。必要に応じて凹部の深さまたは凸部の高さを連
続的に変化させることも可能である。深さを変化させる
ときは光源から遠ざかるに従い深くして拡散効率を上げ
ることが好ましい。凹部内面または凸部外面は梨地な
ど、粗面化することも可能である。以上述べた実施例に
おけるパターンは印刷法で半透明または白色インキ等を
利用して形成しても良い。また、真空蒸着法、サンドブ
ラスト法、フォトエッチング法を利用することも可能で
ある。The cross-sectional shape of the concave portions or convex portions constituting the pattern may be arbitrary, but various shapes such as a V-shape, a square shape, a hemispherical shape, and a polygonal shape can be used. In any case, it can be easily manufactured by injection molding using a mold. In the case of the concave portion, the V-shape can be manufactured by cutting, and the control of the reflection angle can be easily performed, so that the sectional shape is preferable. The depth of the concave portion (groove portion) or the height of the convex portion is appropriately about 0.01 to 0.5 mm. If necessary, the depth of the concave portion or the height of the convex portion can be continuously changed. When changing the depth, it is preferable to increase the diffusion efficiency as the distance from the light source increases. The inner surface of the concave portion or the outer surface of the convex portion may be roughened such as matte finish. The patterns in the above-mentioned embodiments may be formed by using a semitransparent or white ink by a printing method. Further, it is also possible to use a vacuum deposition method, a sandblast method, or a photoetching method.
【００１２】導光板の板形状は厚さの一定した板状でも
よいが、図４に示すように光源から遠くなるに従い薄く
なる楔状とすることが可能である。厚さが一定の板状の
場合は光源側の端面と対向する端面に光反射面を設ける
事が好ましい。楔形状の場合は対向端面の反射面が必ず
しも必要ではなく、また導光板自体の重量を減らすこと
が出来る。透明導光板の素材としてはアクリル樹脂、ポ
リカーボネイト、ＣＲ−３９、ポリスチレンなど透明プ
ラスチックが用いられ、成型の容易さ、透明度の高さ、
キズのつきにくさなどからアクリル樹脂が特に好まし
い。導光板の大きさは任意であるが、液晶パネルのバッ
クライトとして用いるときは対角線の長さは通常約２〜
１０インチである。The plate shape of the light guide plate may be a plate shape having a constant thickness, but as shown in FIG. 4, it is possible to form a wedge shape which becomes thinner as the distance from the light source increases. In the case of a plate having a constant thickness, it is preferable to provide a light reflecting surface on the end surface facing the end surface on the light source side. In the case of the wedge shape, the reflecting surface on the opposite end surface is not always necessary, and the weight of the light guide plate itself can be reduced. Acrylic resin, polycarbonate, CR-39, polystyrene and other transparent plastics are used as the material of the transparent light guide plate, which facilitates molding and has high transparency.
Acrylic resins are particularly preferred because of their scratch resistance. The size of the light guide plate is arbitrary, but when used as a backlight for a liquid crystal panel, the diagonal length is usually about 2 to 2.
It is 10 inches.
【００１３】図４に示す本発明の導光板を用いる平面照
光装置３では、光源Ｌから入射した光が導光板ＬＧ自体
の裏面１の凹部または凸部に入射し、一部は反射して直
接導光板の出射面あるいは他の凹部又は凸部に向って進
むが、透過する光線もある。このように導光板自体の裏
面１から透過してロスとなる光線を、再び導光板に戻し
て光線の有効利用を図るために、導光板の裏面に近接し
て別の反射シート２を配置することが望ましい。反射シ
ートとしては、アルミ蒸着シートなどの反射シート、又
は、白色の光拡散シートを用いてもよい。導光板に設け
られたパターンはその全部を照光装置の有効面として使
う必要はなく、例えば通常光源側と対向する端部ではパ
ターンを形成する曲線の共通接線ライン（例えば図１の
線Ｃ）から数ミリ乃至数十ミリ内側が照光有効面端部と
なるようにすることが可能である。In the flat illumination device 3 using the light guide plate of the present invention shown in FIG. 4, the light incident from the light source L is incident on the concave portion or the convex portion of the back surface 1 of the light guide plate LG itself, and a part thereof is reflected and directly reflected. Some light rays travel toward the exit surface of the light guide plate or other recesses or projections, but are also transmitted. In this way, another reflection sheet 2 is arranged close to the back surface of the light guide plate in order to return the light beam that is transmitted from the back surface 1 of the light guide plate itself and becomes a loss to the light guide plate again to effectively utilize the light beam. Is desirable. As the reflection sheet, a reflection sheet such as an aluminum vapor deposition sheet or a white light diffusion sheet may be used. It is not necessary to use the entire pattern provided on the light guide plate as an effective surface of the illumination device. For example, from the common tangent line (for example, line C in FIG. 1) of the curve forming the pattern at the end facing the light source side. The inside of several millimeters to several tens of millimeters can be the edge of the effective illumination surface.
【００１４】本発明の平面照光装置を用いた液晶画像表
示装置は、図４に示すように基本的には液晶表示パネル
４、光拡散シート５、平面照光装置３、とから構成され
ている。液晶表示パネル４と光拡散シート５との間にプ
リズム板６を設けて特定の視野方向のみの角度の輝度を
向上させることも可能である。このプリズム板６はプリ
ズム面を拡散板側に配置しても良いし、反対にしても良
い。プリズム板に替えてレンチキュラレンズシートを使
用することも可能である。A liquid crystal image display device using the flat illumination device of the present invention basically comprises a liquid crystal display panel 4, a light diffusion sheet 5, and a flat illumination device 3, as shown in FIG. It is also possible to provide a prism plate 6 between the liquid crystal display panel 4 and the light diffusion sheet 5 to improve the brightness at an angle only in a specific visual field direction. The prism surface of the prism plate 6 may be arranged on the side of the diffusion plate, or may be reversed. It is also possible to use a lenticular lens sheet instead of the prism plate.
【００１５】次に本発明の具体例について説明する。第
１実施例で用いた透明導光板のパターンは複数の半円か
ら構成されたものであり、円の半径が約９０ｍｍ、各円
曲線の間隔は中心点において約１．６ｍｍである。パタ
ーンを構成する円の各々は凹部（溝部）から構成され、
その断面は頂角９０度のＶ字型で深さは約０．０５〜
０．１５ｍｍであり、光源から離れるに従って連続的に
深くなっている。上端縁Ａに沿って光源となる蛍光管Ｌ
を配置し、該蛍光管は照度効率を上げるため半円状反射
シート７で覆われている。導光板のサイズは４インチ表
示板対応のもので約８５×７０ｍｍであり、厚さは光源
側端面で約４ｍｍ、対向端部が約１ｍｍであり楔型形状
をしている。この対向端部における照光面としての有効
面端部はパターン曲線の共通接線ラインＣから約１０ｍ
ｍ内側となっている。このような装置で導光板出射面の
輝度を調べたところ図５及び下記表１に示す結果を得
た。この結果は光源からの距離に応じて多少の輝度斑は
あるが従来品に比べれば著しく均一化されており平均で
は約３４１０ニットと言う高いレベルの均一輝度を達成
した。Next, specific examples of the present invention will be described. The pattern of the transparent light guide plate used in the first embodiment is composed of a plurality of semicircles, the radius of the circle is about 90 mm, and the interval between the circular curves is about 1.6 mm at the center point. Each of the circles forming the pattern is composed of a recess (groove),
Its cross section is V-shaped with a vertical angle of 90 degrees and the depth is about 0.05 ~
It is 0.15 mm, and becomes deeper continuously as the distance from the light source increases. Along the upper edge A, a fluorescent tube L serving as a light source
, And the fluorescent tube is covered with a semicircular reflection sheet 7 in order to improve the illuminance efficiency. The size of the light guide plate is about 85 × 70 mm for a 4-inch display plate, and the thickness is about 4 mm at the end surface on the light source side and about 1 mm at the opposite end portion, which has a wedge shape. The end of the effective surface as the illuminated surface at the opposite end is about 10 m from the common tangent line C of the pattern curve.
It is on the inside. When the brightness of the exit surface of the light guide plate was examined with such an apparatus, the results shown in FIG. 5 and Table 1 below were obtained. As a result, although there are some brightness irregularities depending on the distance from the light source, the brightness is more uniform than that of the conventional product, and a high level of uniform brightness of about 3410 nits is achieved.
【表１】 同じサイズの透明導光板の裏面に図６に示した従来例パ
ターンを白色インキのグラデーション印刷で形成し、他
の光学的条件は同等に設定して平面照光装置を作った。
この照光装置の出射面輝度は図５及び表１に従来例とし
て示す通りであり、平均の輝度は約３０９５ニットであ
り、本発明具体例に比べて平均１０％輝度が低かった。[Table 1] The conventional pattern shown in FIG. 6 was formed on the back surface of a transparent light guide plate of the same size by gradation printing of white ink, and the other optical conditions were set to be equal to make a flat illumination device.
The emission surface brightness of this illumination device is as shown in FIG. 5 and Table 1 as a conventional example, and the average brightness was about 3095 nits, which was 10% lower than the specific example of the present invention on average.
【００１６】[0016]
【発明の効果】本発明によれば円半径、曲線の曲率、中
心点のピッチ、凹部、凸部の深さや高さ、その断面形状
など多くのパラメーターを機械的に調節する事が容易で
あり、輝度が高く均一性に優れた調光パターンを設計す
ることが容易であり、また設計通りの導光板を容易に製
造することが可能である。その結果、輝度が高いのみで
なく均一性も高い照光装置を容易に、安価に提供するこ
とが可能である。According to the present invention, it is easy to mechanically adjust many parameters such as the radius of the circle, the curvature of the curve, the pitch of the center points, the depth and height of the concave and convex portions, and the cross-sectional shape thereof. It is easy to design a dimming pattern having high brightness and excellent uniformity, and it is possible to easily manufacture a light guide plate as designed. As a result, it is possible to easily and inexpensively provide an illuminating device having high brightness as well as high uniformity.
【図１】本発明の一実施例としての調光パターンを備え
た透明導光板を示す平面図である。FIG. 1 is a plan view showing a transparent light guide plate having a dimming pattern as an embodiment of the present invention.
【図２】本発明の別実施例としての調光パターンを備え
た透明導光板を示す平面図である。FIG. 2 is a plan view showing a transparent light guide plate having a dimming pattern as another embodiment of the present invention.
【図３】本発明の別の実施例としてＬ字状光源を用いた
ときの調光パターンを備えた導光板の平面図である。FIG. 3 is a plan view of a light guide plate having a dimming pattern when an L-shaped light source is used as another embodiment of the present invention.
【図４】本発明の平面照光装置及び液晶画像表示装置の
概略構成を示す斜視図である。FIG. 4 is a perspective view showing a schematic configuration of a flat illumination device and a liquid crystal image display device of the present invention.
【図５】図１に示す実施例における導光板の出射面の輝
度分布を示すグラフである。5 is a graph showing a luminance distribution on an emission surface of the light guide plate in the example shown in FIG.
【図６】従来の代表的な調光パターンを示す平面図であ
る。FIG. 6 is a plan view showing a conventional typical dimming pattern.
１ 導光板の裏面 ２ 反射シート ３ 平面照光装置 ４ 液晶表示パネル ５ 光拡散シート ６ プリズム板 ７ 半円状反射シート Ｌ 光源 ＬＧ 透明導光板 Ａ 上縁 Ｂ 下縁 Ｃ 共通接線 1 Back surface of light guide plate 2 Reflection sheet 3 Flat illumination device 4 Liquid crystal display panel 5 Light diffusion sheet 6 Prism plate 7 Semi-circular reflection sheet L Light source LG Transparent light guide plate A Upper edge B Lower edge C Common tangent line
Claims (12)
方光源型平面照光装置に用いる導光板であって、該導光
板の裏面には複数曲線からなる調光パターンが設けら
れ、該調光パターンの各曲線が、前記導光板の側面部領
域においては光源側側面部とほぼ垂直であるが、光源側
側面部に対向する他端面部においてはほぼ平行であるこ
とを特徴とする導光板。1. A light guide plate for use in a lateral light source type flat illumination device in which a light source is arranged on a side surface of a transparent light guide plate, wherein a light control pattern composed of a plurality of curves is provided on a back surface of the light guide plate. Each curve of the dimming pattern is substantially perpendicular to the light source side surface portion in the side surface region of the light guide plate, but is substantially parallel to the other end surface portion facing the light source side surface portion. Light board.
を配置した側方光源型平面照光装置に用いる導光板であ
って、該導光板の裏面には複数曲線からなる調光パター
ンが設けられ、該調光パターンが、円の中心点または多
次曲線の原点が一直線上又は円曲線上を実質的に等間隔
にずらして描いた複数の曲線から構成されることを特徴
とする導光板。2. A light guide plate for use in a lateral light source type flat illumination device in which point or line light sources are arranged on a side surface of a transparent light guide plate, and a light control pattern having a plurality of curves is provided on a back surface of the light guide plate. The light control plate is characterized in that the dimming pattern is composed of a plurality of curves in which the center point of a circle or the origin of a multi-order curve is drawn on a straight line or on a circular curve at substantially equal intervals. .
パターン曲線が凹部もしくは凸部で構成されていること
を特徴とする導光板。3. The light guide plate according to claim 2, wherein the dimming pattern curve on the back surface is formed by a concave portion or a convex portion.
と実質的に平行して配置されているクレーム２の導光
板。4. The light guide plate according to claim 2, wherein the light source is a cathode ray tube and is arranged substantially parallel to the side surface portion on the light source side.
させたクレーム２の導光板。5. The light guide plate according to claim 2, wherein the shape of the side surface on the light source side is similar to the shape of a cathode ray tube.
クレーム２の導光板。6. The light guide plate according to claim 2, wherein the light source is one or a plurality of LEDs.
ターン曲線を形成する凹部もしくは凸部の断面形状がＶ
字型、角型または半円形型であることを特徴とする導光
板。7. The light guide plate according to claim 3, wherein the sectional shape of the concave portion or the convex portion forming the dimming pattern curve is V.
A light guide plate having a character shape, a square shape, or a semicircular shape.
側面部における各調光パターン曲線の間隔が約０．３〜
２．０ｍｍであり、かつ該各曲線を構成する凹部又は凸
部断面の段差が約０．０１〜０．５ｍｍであることを特
徴とする導光板。8. The light guide plate according to claim 3, wherein the distance between the dimming pattern curves on the side surface on the light source side is about 0.3 to.
A light guide plate having a length of 2.0 mm and a step difference of a cross section of a concave portion or a convex portion forming each curve is about 0.01 to 0.5 mm.
の厚さが、前記光源側側面部からそれに対向する他端面
に向かって順次減少することを特徴とする導光板。9. The light guide plate according to claim 2, wherein the thickness of the light guide plate gradually decreases from the light source side surface portion toward the other end surface facing the side surface portion.
厚さが実質的に一定である導光板。10. The light guide plate according to claim 2, wherein the thickness of the light guide plate is substantially constant.
導光板の裏面に反射面を配置した側方光源型平面照光装
置において、該導光板の裏面には断面が凹部もしくは凸
部で構成されたあるいは印刷によって構成された複数曲
線からなる調光パターンが設けられ、該調光パターン
が、円の中心点または多次曲線の原点が一直線上又は円
曲線上を実質的に等間隔にずらして描いた複数の曲線か
ら構成された前記導光板を備えたことを特徴とする平面
照光装置。11. A light source is arranged on a side surface of the transparent light guide plate,
In a lateral light source type flat illumination device in which a reflecting surface is arranged on the back surface of a light guide plate, on the back surface of the light guide plate there is a dimming pattern consisting of a plurality of curved lines whose cross section is formed by concave or convex portions or by printing. The dimming pattern is provided with the light guide plate, which is composed of a plurality of curves in which the center point of the circle or the origin of the multi-order curve is drawn on a straight line or on the circle curve at substantially equal intervals. A flat illumination device characterized by the above.
射するための導光板の側面部に光源を配置し、導光板の
裏面に反射面を配置した側方光源型平面照光装置と、該
平面照光装置と前記液晶表示パネルとの間に光拡散板を
配置してなる液晶画像表示装置において、該平面照光装
置の導光板の裏面には断面が凹部もしくは凸部で構成さ
れたあるいは印刷によって構成された複数曲線からなる
調光パターンが設けられ、該調光パターンが、円の中心
点または多次曲線の原点が一直線上又は円曲線上又は円
周上を実質的に等間隔にずらして描いた複数の曲線から
構成されることを特徴とする液晶画像表示装置。12. A liquid crystal display panel, a side light source type flat illumination device in which a light source is arranged on a side surface portion of a light guide plate for irradiating the liquid crystal display panel from the back surface, and a reflecting surface is arranged on the back surface of the light guide plate, and the flat surface. In a liquid crystal image display device in which a light diffusing plate is arranged between an illuminating device and the liquid crystal display panel, the back surface of the light guide plate of the flat illuminating device has a concave or convex cross section or is formed by printing. A dimming pattern consisting of a plurality of curved lines is provided, and the dimming pattern is drawn such that the center point of the circle or the origin of the multi-order curve is aligned on a straight line or on a circular curve or on a circumference at substantially equal intervals. A liquid crystal image display device comprising a plurality of curved lines.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02198195A JP3394623B2 (en) | 1994-02-10 | 1995-02-09 | Light guide plate and flat lighting device using the same |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1659594 | 1994-02-10 | ||
| JP6-16595 | 1994-02-10 | ||
| JP02198195A JP3394623B2 (en) | 1994-02-10 | 1995-02-09 | Light guide plate and flat lighting device using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07270617A true JPH07270617A (en) | 1995-10-20 |
| JP3394623B2 JP3394623B2 (en) | 2003-04-07 |
Family
ID=26352966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP02198195A Expired - Fee Related JP3394623B2 (en) | 1994-02-10 | 1995-02-09 | Light guide plate and flat lighting device using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3394623B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20020036455A (en) * | 2000-11-10 | 2002-05-16 | 유성종 | Light guide panel in LCD having a pattern for printless |
| US8317386B2 (en) | 2006-07-24 | 2012-11-27 | Panasonic Corporation | Laser-lit planar illumination device and LCD using such device |
-
1995
- 1995-02-09 JP JP02198195A patent/JP3394623B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20020036455A (en) * | 2000-11-10 | 2002-05-16 | 유성종 | Light guide panel in LCD having a pattern for printless |
| US8317386B2 (en) | 2006-07-24 | 2012-11-27 | Panasonic Corporation | Laser-lit planar illumination device and LCD using such device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3394623B2 (en) | 2003-04-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5775791A (en) | Surface emission apparatus | |
| JP4454020B2 (en) | Light source device and light deflection element | |
| US5040098A (en) | Backlight for an electronic display | |
| US6981792B2 (en) | Backlight device and liquid crystal display device | |
| JP2562265B2 (en) | Light control sheet | |
| US6971782B2 (en) | Illumination device and liquid crystal display device | |
| JP2004179116A (en) | Back illumination device and liquid crystal display | |
| CN102955195B (en) | The processing method of light guide plate, mould and mould | |
| JP4343474B2 (en) | Optical waveguide having one or more integrated diffusers | |
| JPH10206643A (en) | Sheet-like light source device | |
| KR101692888B1 (en) | Light guiding panel and back light unit using the same | |
| JPH06250025A (en) | Light diffusing device | |
| JP4119633B2 (en) | Surface light source device and light guide used therefor | |
| JPH07318709A (en) | Light control sheet | |
| JPH06123885A (en) | Surface light source device | |
| JPH07318729A (en) | Back light | |
| JP3513944B2 (en) | Backlight | |
| JP2000171798A (en) | Back light device | |
| JP3394623B2 (en) | Light guide plate and flat lighting device using the same | |
| KR20190134439A (en) | Light guide plate having engraved pattern and back light unit using the same | |
| JP2000067624A (en) | Surface light source device | |
| KR100344474B1 (en) | Light conductive plate and illuminating apparatus using the same | |
| JP2004233938A (en) | Optical deflection element and light source device | |
| JPH06235825A (en) | Surface light source device | |
| JP2001006418A (en) | Lighting system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313111 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090131 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100131 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110131 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110131 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120131 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120131 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130131 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130131 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140131 Year of fee payment: 11 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |