JPH07272507A - Backlight unit - Google Patents
Backlight unitInfo
- Publication number
- JPH07272507A JPH07272507A JP6062953A JP6295394A JPH07272507A JP H07272507 A JPH07272507 A JP H07272507A JP 6062953 A JP6062953 A JP 6062953A JP 6295394 A JP6295394 A JP 6295394A JP H07272507 A JPH07272507 A JP H07272507A
- Authority
- JP
- Japan
- Prior art keywords
- fluorescent lamp
- lamp
- backlight unit
- fluorescent lamps
- fluorescent
- 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.)
- Withdrawn
Links
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- Non-Portable Lighting Devices Or Systems Thereof (AREA)
- Planar Illumination Modules (AREA)
- Vessels And Coating Films For Discharge Lamps (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、液晶テレビなどに使用
される液晶ディスプレイパネル用バックライトユニット
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit for a liquid crystal display panel used in a liquid crystal television or the like.
【０００２】[0002]
【従来の技術】液晶ディスプレイパネルのバックライト
は、光源に細長い蛍光ランプを使用した矩形薄形のバッ
クライトユニットが、高輝度で低消費電力であることか
ら実用化されている。このバックライトユニットの従来
例を、図４及び図５を参照して説明する。2. Description of the Related Art A backlight of a liquid crystal display panel has been put into practical use because a rectangular thin backlight unit using a long and narrow fluorescent lamp as a light source has high brightness and low power consumption. A conventional example of this backlight unit will be described with reference to FIGS. 4 and 5.
【０００３】同図に示されるバックライトユニットは、
矩形皿状の反射板１と矩形の透過性拡散板３で形成され
た扁平なランプハウス５内のランプ空間ｍに２本のＵ形
蛍光ランプ６、７を配置した直下型２灯用バックライト
ユニットである。各蛍光ランプ６、７は同一構造のもの
で、反射板１と平行にして所定間隔で並列に配置され
る。反射板１は、蛍光ランプ６、７の光を拡散板３に向
けて反射するもので、例えばアルミニウム板に白色塗装
を施し、その塗装面に銀蒸着シートなどの反射シート２
を貼着したものや、樹脂板に反射シート２を貼着したも
のである。拡散板３は、蛍光ランプ６、７の光を拡散さ
せて透過させるアクリル樹脂板などで、これの裏面に必
要に応じて蛍光ランプ点灯時の輻射ノイズの漏洩を防止
する導電シート４が貼着される。The backlight unit shown in FIG.
A direct type backlight for two lights in which two U-shaped fluorescent lamps 6 and 7 are arranged in a lamp space m in a flat lamp house 5 formed by a rectangular dish-shaped reflector 1 and a rectangular transmissive diffuser 3 It is a unit. The fluorescent lamps 6 and 7 have the same structure and are arranged in parallel with the reflector 1 at a predetermined interval. The reflection plate 1 reflects the light of the fluorescent lamps 6 and 7 toward the diffusion plate 3. For example, a white coating is applied to an aluminum plate, and a reflection sheet 2 such as a silver vapor deposition sheet is applied to the coated surface.
Is attached, or the reflection sheet 2 is attached to a resin plate. The diffusion plate 3 is an acrylic resin plate or the like that diffuses and transmits the light of the fluorescent lamps 6 and 7, and a conductive sheet 4 for preventing leakage of radiation noise when the fluorescent lamp is lit is attached to the back surface of the acrylic resin plate or the like. To be done.
【０００４】ランプハウス５の片端部に回路ハウジング
１０が連結され、回路ハウジング１０内に蛍光ランプ
６、７を高周波点灯させるインバータ回路１１が収納さ
れる。インバータ回路１１は、図示しないが発振トラン
スや複数の発振トランジスタなどで構成され、高周波電
圧が印加される４つの出力端子１２のそれぞれに２本の
蛍光ランプ６、７の両端部の電極（図示せず）がリード
線９で接続される。A circuit housing 10 is connected to one end of the lamp house 5, and an inverter circuit 11 for turning on the fluorescent lamps 6 and 7 at a high frequency is housed in the circuit housing 10. The inverter circuit 11 is composed of an oscillating transformer, a plurality of oscillating transistors, and the like, which are not shown, and electrodes of both ends of the two fluorescent lamps 6 and 7 (not shown) are respectively provided to the four output terminals 12 to which a high frequency voltage is applied. No.) is connected by the lead wire 9.
【０００５】インバータ回路１１で蛍光ランプ６、７を
高周波点灯させると、その光の一部は直接に、残りは反
射板１を反射して拡散板３に入り、拡散板３で拡散して
光分布が均一化されて透過し、拡散板３上の液晶ディス
プレイパネル（図示せず）を照射する。When the fluorescent lamps 6 and 7 are turned on at a high frequency by the inverter circuit 11, a part of the light is directly reflected and the rest is reflected by the reflection plate 1 and enters the diffusion plate 3, and is diffused by the diffusion plate 3 to emit light. The distribution is made uniform and transmitted, and the liquid crystal display panel (not shown) on the diffusion plate 3 is illuminated.
【０００６】[0006]
【発明が解決しようとする課題】液晶ディスプレイパネ
ルの薄形化により図４のようなバックライトユニットも
薄いものが要求され、この要求から光源に使用される蛍
光ランプ６、７は、管径が２．５〜５ｍｍの細長いもの
が使用され、これの点灯手段に小形化が容易なインバー
タ回路１１が適用されている。このような蛍光ランプ
６、７をインバータ点灯させたときの拡散板３上での輝
度は、拡散板３上の全域で均一であることが望ましいの
であるが、拡散板３の中央部の輝度が高く、拡散板３の
周辺部の輝度が低くなり、特に２本の蛍光ランプ６、７
の外側端部の部分での輝度が低くなる傾向にある。実
際、拡散板３上の蛍光ランプ配列方向での輝度分布は、
図６に示すように拡散板３の中央部で高く、両端部で低
くなり、拡散板３の全体の輝度均斉度が製品によってば
らつく傾向にある。Due to the thinning of the liquid crystal display panel, a backlight unit as shown in FIG. 4 is required to be thin. From this requirement, the fluorescent lamps 6 and 7 used as a light source have a tube diameter of A long and narrow strip having a length of 2.5 to 5 mm is used, and an inverter circuit 11 which can be easily miniaturized is applied to the lighting means thereof. It is desirable that the brightness on the diffuser plate 3 when the fluorescent lamps 6 and 7 are turned on by the inverter is uniform over the entire area on the diffuser plate 3, but the brightness of the central portion of the diffuser plate 3 is not uniform. It is high, and the brightness around the diffusion plate 3 is low, and especially the two fluorescent lamps 6 and 7 are
The luminance tends to be low at the outer end portion of the. In fact, the brightness distribution in the fluorescent lamp array direction on the diffusion plate 3 is
As shown in FIG. 6, the central part of the diffuser plate 3 is high and the both end parts are low, and the luminance uniformity of the entire diffuser plate 3 tends to vary depending on the product.
【０００７】このような拡散板３上の中央部と両端部の
輝度のばらつきの度合は、液晶ディスプレイパネルのバ
ックライトとして問題にならない程度の場合もあるが、
問題となる場合もあり、安定していないのが現状であ
る。また、拡散板３上の中央部と両端部の輝度のばらつ
きの度合が問題となる傾向は、近年の液晶ディスプレイ
パネルの高品質化に伴って増加しているのが現状であ
る。The degree of variation in the brightness of the central part and both ends of the diffuser plate 3 may not be a problem as a backlight of a liquid crystal display panel in some cases.
In some cases, it may be a problem and it is not stable at present. In addition, the tendency that the degree of variation in brightness between the central portion and both end portions on the diffusion plate 3 becomes a problem is increasing with the recent improvement in quality of liquid crystal display panels.
【０００８】本発明の目的とするところは、拡散板の中
央部と周辺部の輝度のばらつきの度合を改善できる蛍光
ランプ用バックライトユニットを提供することにある。An object of the present invention is to provide a backlight unit for a fluorescent lamp, which can improve the degree of variation in brightness between the central portion and the peripheral portion of the diffusion plate.
【０００９】[0009]
【課題を解決するための手段】本発明は、反射板と透過
性拡散板で形成された扁平なランプ空間に複数のＵ形蛍
光ランプを所定間隔で並列に配置して、各蛍光ランプを
インバータ回路で点灯させるようにしたバックライトユ
ニットにおいて、ランプ空間の蛍光ランプ配列方向の両
端部に位置する蛍光ランプの外側端部の電極を、この蛍
光ランプの他の内側端部の電極よりも高電圧を印加する
インバータ回路の高電圧側出力端子に接続する構成、及
び又は、ランプ空間の蛍光ランプ配列方向の両端部に位
置する蛍光ランプの外側端部のガラス管内に形成された
蛍光体被膜の膜厚が、この蛍光ランプの他の内側端部で
の蛍光体被膜の膜厚より大きくなるよう構成したことを
特徴とする。According to the present invention, a plurality of U-shaped fluorescent lamps are arranged in parallel at a predetermined interval in a flat lamp space formed by a reflector and a transmissive diffuser, and each fluorescent lamp is an inverter. In a backlight unit that is lit by a circuit, the electrodes at the outer ends of the fluorescent lamps located at both ends of the lamp space in the fluorescent lamp array direction have a higher voltage than the electrodes at the other inner ends of the fluorescent lamp. A structure for connecting to the high voltage side output terminal of the inverter circuit for applying, and / or a film of a phosphor coating formed in the glass tube at the outer end of the fluorescent lamp located at both ends of the lamp space in the fluorescent lamp array direction. It is characterized in that the thickness is made larger than the film thickness of the phosphor coating on the other inner end portion of the fluorescent lamp.
【００１０】[0010]
【作用】本発明者は、液晶ディスプレイパネルの直下型
バックライトユニットのＵ形蛍光ランプの両端部真上で
の輝度のばらつき発生の原因を実験により追求した結
果、次の２つのことを知り得た。即ち、インバータ回路
で点灯する蛍光ランプの両端部の電極に印加される高周
波電圧に差があり、グランドレベルで比較的高電圧が印
加される電極の在る側の蛍光ランプの片端部の真上の輝
度が、比較的低電圧が印加される電極の在る側の蛍光ラ
ンプの他の端部の真上の輝度より高くなる傾向にあるこ
とが分かった。また、蛍光ランプの蛍光体被膜は、ガラ
ス管内周面に蛍光体懸濁液を流して塗布し、これを乾燥
させ焼成して形成しているが、この形成工程でガラス管
の両端部内の蛍光体被膜の膜厚に差が生じて、蛍光ラン
プを点灯させると蛍光体被膜の膜厚の大きい方の端部
が、膜厚の小さい方の端部より明るくなる傾向があるこ
とも分かった。The inventor of the present invention can know the following two results as a result of conducting an experiment to investigate the cause of the variation in the brightness just above both ends of the U-shaped fluorescent lamp of the backlight unit directly under the liquid crystal display panel. It was That is, there is a difference in the high-frequency voltage applied to the electrodes at both ends of the fluorescent lamp that is lit by the inverter circuit, and it is directly above one end of the fluorescent lamp on the side where the electrode to which a relatively high voltage is applied at the ground level is present. It has been found that the luminance of the LED tends to be higher than the luminance directly above the other end of the fluorescent lamp on the side where the electrode to which the relatively low voltage is applied is present. Further, the phosphor coating of the fluorescent lamp is formed by flowing and applying a phosphor suspension on the inner peripheral surface of the glass tube, and drying and baking the suspension. It was also found that there is a difference in the film thickness of the body coating, and when the fluorescent lamp is turned on, the end portion of the phosphor coating having a larger film thickness tends to be brighter than the end portion having a smaller film thickness.
【００１１】以上の２つの傾向は、管径が５ｍｍ以下と
細長い冷陰極型蛍光ランプにおいて強く見られ、このよ
うな傾向にあるＵ形蛍光ランプの複数本を、反射板と拡
散板の間の扁平なランプ空間に無造作に配置し、インバ
ータ回路に無造作に配線すると、上記した拡散板の中央
部と両端部上での輝度に問題となるばらつきが発生する
ことがある。そこで、ランプ空間に並列に配置される複
数本のＵ形蛍光ランプの内の外側の２本のＵ形蛍光ラン
プの高電圧が印加される側の端部が、ランプ空間のラン
プ配列方向の両端部の位置になるようにすると、この両
端部に対応する拡散板の両端部の輝度を高く設定でき
る。或いは、ランプ空間に並列に配置される複数本のＵ
形蛍光ランプの内の外側の２本のＵ形蛍光ランプの蛍光
体被膜の膜厚の大きい方の端部が、ランプ空間のランプ
配列方向の両端部の位置になるようにすると、この両端
部に対応する拡散板の両端部の輝度を高く設定できる。
更に、ランプ空間に並列に配置される複数本のＵ形蛍光
ランプの内の外側の２本のＵ形蛍光ランプの高電圧が印
加され、かつ、蛍光体被膜の膜厚の大きい方の端部が、
ランプ空間のランプ配列方向の両端部の位置になるよう
にすると、この両端部に対応する拡散板の両端部の輝度
が尚更に高く設定できる。The above two tendencies are strongly observed in the elongated cold cathode fluorescent lamps having a tube diameter of 5 mm or less, and a plurality of U-shaped fluorescent lamps having such a tendency are flattened between the reflection plate and the diffusion plate. If the lamps are randomly arranged in the lamp space and randomly wired in the inverter circuit, a problematic variation may occur in the brightness on the central portion and both end portions of the diffusion plate. Therefore, the ends of the outer two U-shaped fluorescent lamps of the plurality of U-shaped fluorescent lamps arranged in parallel in the lamp space on the side to which the high voltage is applied are both ends of the lamp space in the lamp arrangement direction. By setting the positions of the parts, it is possible to set the brightness of both ends of the diffusion plate corresponding to the both ends to be high. Alternatively, a plurality of Us arranged in parallel in the lamp space
When the ends of the two outer U-shaped fluorescent lamps having the larger thickness of the phosphor coating of the U-shaped fluorescent lamp are located at both ends of the lamp space in the lamp arrangement direction, the both ends are formed. The brightness of both ends of the diffusion plate corresponding to can be set high.
Further, the high voltage of the outer two U-shaped fluorescent lamps of the plurality of U-shaped fluorescent lamps arranged in parallel in the lamp space is applied, and the end portion of the phosphor coating having the larger film thickness is applied. But,
When the lamp space is located at both ends in the lamp arrangement direction, the brightness at both ends of the diffusion plate corresponding to the both ends can be set to be still higher.
【００１２】以上のように扁平なランプ空間に複数本の
Ｕ形蛍光ランプを配置すると、拡散板のランプ配列方向
の両端部の輝度アップした分に相応して中央部の輝度が
ダウンし、結果的に拡散板上の中央部と周辺部の輝度が
均衡して、拡散板上全体の輝度均斉度が確実に向上する
ことが認知された。When a plurality of U-shaped fluorescent lamps are arranged in the flat lamp space as described above, the brightness of the central part is lowered corresponding to the increase of the brightness of both ends of the diffuser plate in the lamp arrangement direction. It was recognized that the brightness of the central part and the peripheral part on the diffuser plate was balanced and the brightness uniformity of the entire diffuser plate was surely improved.
【００１３】[0013]
【実施例】以下、実施例について図１乃至図３を参照し
て説明する。尚、図４乃至図６を含む全図を通じ同一、
又は、相当部分には同一符号を付して説明は省略する。EXAMPLES Examples will be described below with reference to FIGS. 1 to 3. It should be noted that, in all the drawings including FIG. 4 to FIG.
Alternatively, the corresponding parts are denoted by the same reference numerals and the description thereof is omitted.
【００１４】図１に示されるバックライトユニットは、
図４と同一タイプのもので、反射板１と拡散板３で形成
されたランプ空間ｍに並列に配置された２本のＵ形蛍光
ランプ６、７の配列形態と、このＵ形蛍光ランプ６、７
と回路ハウジング１０に収納されたインバータ回路１１
の配線形態を特徴としている。The backlight unit shown in FIG.
An arrangement form of two U-shaped fluorescent lamps 6 and 7 of the same type as in FIG. 4 and arranged in parallel in a lamp space m formed by a reflection plate 1 and a diffusion plate 3, and this U-shaped fluorescent lamp 6 , 7
And the inverter circuit 11 housed in the circuit housing 10
Is characterized by the wiring form.
【００１５】２本の蛍光ランプ６、７は同一構造で、各
蛍光ランプ６、７はＵ形ガラス管６’、７’の内周面に
蛍光体被膜８を有し、各蛍光ランプ６、７の両端部内に
電極（図示せず）が封入され、この各電極から外に導出
されたリード線９がインバータ回路１１の対応する出力
端子１２に接続される。インバータ回路１１の出力端子
１２は、各蛍光ランプ６、７をインバータ点灯させると
きにグランドレベルで比較して高電圧側となる出力端子
１２Ｈと、低電圧側となる出力端子１２Ｌの各一対で構
成される。この電圧差のある各一対の出力端子１２Ｈ、
１２Ｌは、インバータ回路１１における発振トランス
（図示せず）との配線で決まる。尚、出力端子１２Ｈ、
１２Ｌはソケットにて代用することもできるし、また、
特別の端子を用いることなくインバータ回路と直接的に
接続することもできる。本発明における出力端子はこの
ようなものを含むものとする。The two fluorescent lamps 6, 7 have the same structure. Each fluorescent lamp 6, 7 has a phosphor coating 8 on the inner peripheral surface of the U-shaped glass tubes 6 ', 7'. Electrodes (not shown) are enclosed in both ends of 7, and lead wires 9 led out from the respective electrodes are connected to corresponding output terminals 12 of the inverter circuit 11. The output terminal 12 of the inverter circuit 11 is composed of a pair of an output terminal 12H on the high voltage side and an output terminal 12L on the low voltage side in comparison with each other at the ground level when the fluorescent lamps 6 and 7 are turned on by the inverter. To be done. Each pair of output terminals 12H having this voltage difference,
12L is determined by the wiring with the oscillation transformer (not shown) in the inverter circuit 11. The output terminal 12H,
12L can be replaced with a socket, and also
It is also possible to directly connect to the inverter circuit without using a special terminal. The output terminal in the present invention includes such a thing.
【００１６】いま仮に各蛍光ランプ６、７を、その各々
の両端部の電極に印加する電圧レベルの大小を考慮せず
インバータ回路１１に無造作に接続してインバータ点灯
させると、拡散板３上のランプ配列方向の輝度分布が不
安定となる傾向にあることが結果的に分かっている。ま
た、このような輝度分布の不安定さは、液晶ディスプレ
イパネルのバックライトの光源に適した管径２．５〜５
ｍｍ程度の細長い冷陰極型蛍光ランプにおいて目立って
発生する傾向にあることも分かっている。If the fluorescent lamps 6 and 7 are tentatively connected to the inverter circuit 11 and the inverter is turned on without considering the magnitude of the voltage level applied to the electrodes at both ends of the fluorescent lamps 6, the diffuser plate 3 will be illuminated. As a result, it has been found that the luminance distribution in the lamp arrangement direction tends to be unstable. In addition, such instability of the brightness distribution is caused by a tube diameter of 2.5 to 5 suitable for the light source of the backlight of the liquid crystal display panel.
It has also been found that it tends to occur conspicuously in an elongated cold cathode fluorescent lamp of about mm.
【００１７】そこで、本発明においては、ランプ空間ｍ
に並列に配置された２本のＵ形蛍光ランプ６、７の各外
側の端部６ａ、７ａの電極をインバータ回路１１の高電
圧側出力端子１２Ｈに接続し、Ｕ形蛍光ランプ６、７の
各内側の端部６ｂ、７ｂの電極をインバータ回路１１の
低電圧側出力端子１２Ｌに接続してインバータ点灯させ
る。すると、各蛍光ランプ６、７の高電圧側出力端子１
２Ｈに接続された側の外側端部６ａ、７ａの輝度が、低
電圧側出力端子１２Ｌに接続された内側端部６ｂ、７ｂ
の輝度より高くなる傾向にあることが実験で分かった。Therefore, in the present invention, the lamp space m
The electrodes of the outer ends 6a, 7a of the two U-shaped fluorescent lamps 6, 7 arranged in parallel with each other are connected to the high-voltage side output terminal 12H of the inverter circuit 11, and the U-shaped fluorescent lamps 6, 7 are connected. The electrodes of the inner ends 6b and 7b are connected to the low voltage side output terminal 12L of the inverter circuit 11 to light the inverter. Then, the high voltage side output terminal 1 of each fluorescent lamp 6 and 7
The brightness of the outer end portions 6a, 7a on the side connected to 2H is the same as the inner end portions 6b, 7b connected to the low voltage side output terminal 12L.
It was found by the experiment that the luminance tends to be higher than the luminance of.
【００１８】上記のような蛍光ランプ６、７とインバー
タ回路１１の配線でもって、拡散板３上の蛍光ランプ
６、７の外側端部６ａ、７ａの在る両端部の輝度が確実
にアップし、このアップ分に相応して拡散板３の中央部
の輝度がダウンして、結果的に拡散板３の中央部と両端
部の輝度が均衡し、後述する実験データのように拡散板
３上全体の輝度均斉度［（最小輝度／最大輝度）×１０
０］が８５％以上で安定することが分かっている。The wiring of the fluorescent lamps 6 and 7 and the inverter circuit 11 as described above surely increases the brightness of both ends of the fluorescent lamps 6 and 7 on the diffusion plate 3 where the outer end portions 6a and 7a are present. The brightness of the central part of the diffuser plate 3 is lowered corresponding to this increase, and as a result, the brightness of the central part of the diffuser plate 3 and the brightness of both ends are balanced. Overall brightness uniformity [(minimum brightness / maximum brightness) x 10
It is known that 0] is stable at 85% or more.
【００１９】また、本発明は、２本のＵ形蛍光ランプ
６、７の両端部６ａ、６ｂ、７ａ、７ｂの蛍光体被膜の
膜厚の大小を利用している。即ち、１本の蛍光ランプ６
の片端部６ａの蛍光体被膜８の膜厚ｄ1 と他端部６ｂの
蛍光体被膜８の膜厚ｄ2 には若干の差が有る。この膜厚
差は、ガラス管６’の内周面に蛍光体被膜８を形成する
段階で生じる。例えば、両端開口の直管形ガラス管を鉛
直に立て、その上から蛍光体懸濁液を流し込んでガラス
管内面に塗布し、これを乾燥させ焼成して蛍光体被膜形
成が行われるが、ガラス管内に塗布された蛍光体懸濁液
を乾燥させるときに、蛍光体懸濁液が鉛直なガラス管内
面を自重で垂れ下り、このときにガラス管下部の蛍光体
懸濁液の量が増えて、ガラス管下部に形成される蛍光体
被膜の膜厚がガラス管上部の膜厚より大きくなる傾向に
ある。同様に他の蛍光ランプ７の片端部７ａの蛍光体被
膜８の膜厚ｄ1 と他端部７ｂの蛍光体被膜８の膜厚ｄ2
には若干の差が有るThe present invention also utilizes the thickness of the phosphor coating on both ends 6a, 6b, 7a, 7b of the two U-shaped fluorescent lamps 6, 7. That is, one fluorescent lamp 6
There is a slight difference between the film thickness d 1 of the phosphor coating 8 on one end 6a and the film thickness d 2 of the phosphor coating 8 on the other end 6b. This film thickness difference occurs at the stage of forming the phosphor coating 8 on the inner peripheral surface of the glass tube 6 '. For example, a straight glass tube with both ends opened is erected vertically, a phosphor suspension is poured from above to coat the inside of the glass tube, and this is dried and baked to form a phosphor film. When the phosphor suspension applied to the inside of the tube is dried, the phosphor suspension hangs down on the inner surface of the vertical glass tube by its own weight, and at this time, the amount of the phosphor suspension under the glass tube increases. The film thickness of the phosphor coating formed on the lower part of the glass tube tends to be larger than that on the upper part of the glass tube. Similarly, the film thickness d 1 of the phosphor coating 8 on one end 7a and the film thickness d 2 of the phosphor coating 8 on the other end 7b of the other fluorescent lamp 7 are similarly set.
There is a slight difference in
【００２０】尚、このような蛍光ランプ６、７の両端部
６ａ、６ｂ、７ａ、７ｂにおける蛍光体被膜８の膜厚ｄ
1、ｄ2の差は、上記のような蛍光体被膜形成工程上で自
然発生的に生じるのが通常であるが、膜厚ｄ1、ｄ2の差
が所定の範囲で生じるように積極的に蛍光体被膜を形成
するようにしてもよい。The film thickness d of the phosphor coating 8 on both ends 6a, 6b, 7a, 7b of the fluorescent lamps 6, 7 is as follows.
The difference between 1 and d 2 usually occurs spontaneously during the above-mentioned phosphor film forming process, but is positive so that the difference between the film thicknesses d 1 and d 2 occurs within a predetermined range. You may make it form a fluorescent substance coating on it.
【００２１】ランプ空間ｍに２本のＵ形蛍光ランプ６、
７を、その各端部での蛍光体被膜の膜厚差を考慮するこ
と無く無造作に配置してインバータ点灯させた場合にお
いても、拡散板３上のランプ配列方向の輝度分布が不安
定となる傾向にあることが結果的に分かっている。この
ような輝度分布の不安定さは、液晶ディスプレイパネル
のバックライトの光源に適した管径２．５〜５ｍｍ程度
の細長い冷陰極型蛍光ランプにおいて目立って発生する
傾向にあることも分かっている。Two U-shaped fluorescent lamps 6 in the lamp space m,
Even when 7 is randomly arranged without considering the film thickness difference of the phosphor coating at each end and the inverter is turned on, the luminance distribution in the lamp arrangement direction on the diffusion plate 3 becomes unstable. It turns out that there is a tendency. It is also known that such instability of the luminance distribution tends to occur conspicuously in an elongated cold cathode fluorescent lamp having a tube diameter of about 2.5 to 5 mm, which is suitable for a light source of a backlight of a liquid crystal display panel. .
【００２２】ここで本発明においては、２本のＵ形蛍光
ランプ６、７の膜厚大の例えば端部６ａ、７ａが外側端
部となるようにランプ空間ｍの両端部に位置させて配置
する。この蛍光ランプ６、７をインバータ点灯させる
と、各蛍光ランプ６、７の膜厚大の端部６ａ、７ａの輝
度が膜厚小の端部６ｂ、７ｂの輝度より高くなる傾向に
あることが実験で分かった。また、このようなランプ空
間ｍでの蛍光ランプ６、７の配置でもって、拡散板３上
の蛍光ランプ６、７の膜厚大の端部６ａ、７ａの在る両
端部の輝度が確実にアップし、このアップ分に相応して
拡散板３の中央部の輝度がダウンして、結果的に拡散板
３の中央部と両端部の輝度が均衡し、拡散板３上全体の
輝度均斉度が高度に安定する。Here, in the present invention, the two U-shaped fluorescent lamps 6 and 7 are arranged at both ends of the lamp space m so that, for example, the ends 6a and 7a having large film thickness are outer ends. To do. When the fluorescent lamps 6 and 7 are turned on by the inverter, the luminance of the thick film end portions 6a and 7a of each fluorescent lamp 6 and 7 tends to be higher than the luminance of the thin film end portions 6b and 7b. It turned out by experiment. In addition, with the arrangement of the fluorescent lamps 6 and 7 in the lamp space m, the brightness of the both ends of the fluorescent lamps 6 and 7 on the diffusion plate 3 where the end portions 6a and 7a having the large film thickness are surely secured. The brightness of the central part of the diffuser plate 3 is decreased corresponding to this increase, and as a result, the brightness of the central part of the diffuser plate 3 and the brightness of both ends are balanced, and the brightness uniformity of the entire diffuser plate 3 is increased. Is highly stable.
【００２３】図１に示されるバックライトユニットは、
２本並列のＵ形蛍光ランプ６、７の外側端部６ａ、７ａ
の蛍光体被膜８が膜厚大であり、かつ、この外側端部６
ａ、７ａの電極をインバータ回路１１の高電圧側出力端
子１２Ｈに接続し、内側端部６ｂ、７ｂの蛍光体被膜８
が膜厚小であり、この内側端部６ｂ、７ｂの電極をイン
バータ回路１１の低電圧側出力端子１２Ｌに接続してい
る。その結果、拡散板３上の蛍光ランプ６、７の高電圧
側と膜厚大側の外側端部６ａ、７ａの在る両端部の輝度
が、上記した高電圧と膜厚大による輝度アップ効果で尚
更に高くなって、拡散板３の中央部の輝度に尚更に均衡
し、図２に示すように、拡散板３上のランプ配列方向の
輝度が均一化されて全体の輝度均斉度がより高度に安定
することが実験により認知された。The backlight unit shown in FIG.
Outer ends 6a, 7a of two U-shaped fluorescent lamps 6, 7 arranged in parallel
Has a large thickness, and the outer end portion 6
The electrodes of a and 7a are connected to the high voltage side output terminal 12H of the inverter circuit 11, and the phosphor coating 8 of the inner end portions 6b and 7b is connected.
Has a small film thickness, and the electrodes of the inner end portions 6b and 7b are connected to the low voltage side output terminal 12L of the inverter circuit 11. As a result, the brightness of the fluorescent lamps 6 and 7 on the diffuser plate 3 at both ends of the high-voltage side and the large-thickness side outer ends 6a and 7a is increased by the above-described high voltage and large film thickness. The brightness of the central portion of the diffuser plate 3 becomes even higher, and the brightness in the lamp array direction on the diffuser plate 3 is made uniform, as shown in FIG. Experiments have shown that it is highly stable.
【００２４】尚、図１の実施例のバックライトユニット
の配線組立時に、蛍光ランプ６、７の膜厚大の端部６
ａ、７ａをインバータ回路１１の低電圧側出力端子１２
Ｌに間違って接続する配線ミスを防止するため、次のよ
うにしてもよい。例えば、蛍光ランプ６、７の膜厚大の
端部６ａ、７ａの表面に、この端部が目視等で膜厚大側
端部であると分別確認できるマーキングされた塗料、テ
ープなどの図示しない膜厚表示手段を付設しておく。そ
して、蛍光ランプ６、７の膜厚表示手段を目視で確認し
たり、センサで自動検出することで、各蛍光ランプ６、
７の端部の方向性を正確に定めて、インバータ回路１１
に配線するようにすれば、上記配線ミスが防止される。When the wiring of the backlight unit of the embodiment shown in FIG. 1 is assembled, the end portions 6 of the fluorescent lamps 6 and 7 having the large film thickness are assembled.
a and 7a are low-voltage side output terminals 12 of the inverter circuit 11.
In order to prevent wiring mistakes that are erroneously connected to L, the following may be performed. For example, on the surface of the end portions 6a, 7a of the fluorescent lamps 6, 7 having a large film thickness, there is not shown a paint, a tape, etc. on which marking is made so that the end portions can be visually confirmed to be the end portions having a large film thickness. A film thickness display means is attached. Then, by visually confirming the film thickness display means of the fluorescent lamps 6 and 7, or by automatically detecting them by the sensor, each fluorescent lamp 6,
The directionality of the end portion of 7 is accurately determined, and the inverter circuit 11
The wiring mistake can be prevented by arranging the wiring.
【００２５】図１のバックライトユニットの具体例、実
験例を説明する。２本のＵ形蛍光ランプ６、７に、管径
３ｍｍで端部から屈曲部までの長さＬが１３５ｍｍの冷
陰極型蛍光ランプを使用し、ランプハウス５の高さが１
０ｍｍの６インチ画面のバックライトユニットを構成
し、蛍光ランプ６、７を４５ＫＨｚの高周波電圧でイン
バータ点灯させる。このバックライトユニットの拡散板
３上の有効発光面積部分を、図３に示すようにを格子状
に９等分割して、分割された図中〜の各区分域の輝
度を測定した結果の実験データと、同じ蛍光ランプ６、
７をランプハウス５内に無造作に配置した従来の二例を
表１に示す。Specific examples and experimental examples of the backlight unit shown in FIG. 1 will be described. For the two U-shaped fluorescent lamps 6 and 7, cold cathode fluorescent lamps having a tube diameter of 3 mm and a length L from the end to the bent portion of 135 mm are used, and the height of the lamp house 5 is 1 mm.
A 0 mm 6-inch screen backlight unit is configured, and the fluorescent lamps 6 and 7 are turned on by a high-frequency voltage of 45 KHz. An experiment of the results obtained by dividing the effective light emitting area portion on the diffuser plate 3 of this backlight unit into 9 equal parts in a grid pattern as shown in FIG. The same fluorescent data as the data 6,
Table 1 shows two conventional examples in which the lamps 7 are randomly arranged in the lamp house 5.
【００２６】[0026]
【表１】 [Table 1]
【００２７】表１の実験データによると、本発明のバッ
クライトユニットにおける拡散板３上のランプ配列方向
の輝度が均一化されて、拡散板３全体の輝度均斉度が従
来の７０％前後から８５％以上に向上することが分か
る。例えば拡散板３のＵ形蛍光ランプ６、７の端部側の
中央部の輝度が従来例で７６３０Ｃｄ／ｍ2 、７５０
０Ｃｄ／ｍ2 であったのが６５００Ｃｄ／ｍ2 と少し下
がる反面、中央部の両端部、の内のの輝度が従
来例の５８１０Ｃｄ／ｍ2 、５５３０Ｃｄ／ｍ2から６
４３０Ｃｄ／ｍ2 に上がり、の輝度が５５３０Ｃｄ／
ｍ2 、５７５０Ｃｄ／ｍ2 から６５３０Ｃｄ／ｍ2 と上
がって、拡散板３上のランプ配列方向の輝度が均衡する
ことが分かる。また、このような輝度均斉度が８５％以
上のバックライトユニットは、高品質液晶ディスプレイ
パネルのバックライトとして有効であることも分かって
いる。According to the experimental data of Table 1, the luminance in the lamp arrangement direction on the diffuser plate 3 in the backlight unit of the present invention is made uniform, and the luminance uniformity of the entire diffuser plate 3 is from about 70% of the conventional one to 85. It can be seen that it improves to more than%. For example, the brightness of the central portion of the diffusion plate 3 on the end side of the U-shaped fluorescent lamps 6 and 7 is 7630 Cd / m 2 and 750 in the conventional example.
Although that of 0 cd / m was 2 slightly lowers the 6500Cd / m 2, both end portions of the central portion, the luminance of among from 5810Cd / m 2, 5530Cd / m 2 of a conventional example 6
430Cd / m 2 and the brightness of 5530Cd / m 2
up from m 2, 5750Cd / m 2 and 6530Cd / m 2, the luminance of the lamp arrangement direction on the diffusion plate 3 can be seen that the equilibrium. It is also known that such a backlight unit having a brightness uniformity of 85% or more is effective as a backlight for a high quality liquid crystal display panel.
【００２８】尚、本発明は、Ｕ形蛍光ランプの３本以上
を使用した直下型バックライトユニットにおいても適用
される。Ｕ形蛍光ランプの３本を扁平なランプ空間に並
列に配置したバックライトユニットにおいては、両端部
の２本の蛍光ランプについて上記実施例の技術内容を適
用すればよい。The present invention can also be applied to a direct type backlight unit using three or more U-shaped fluorescent lamps. In a backlight unit in which three U-shaped fluorescent lamps are arranged in parallel in a flat lamp space, the technical contents of the above-described embodiments may be applied to the two fluorescent lamps at both ends.
【００２９】[0029]
【発明の効果】本発明によれば、拡散板上のランプ配列
方向の両端部での輝度が、拡散板の中央部の輝度に均衡
する値にまで確実に上がり、拡散板全域の輝度均斉度が
向上化、安定化が可能となって、高品質液晶ディスプレ
イパネルのバックライトとして好適なバックライトユニ
ットが提供できる。また、本発明は、蛍光ランプとイン
バータ回路との配線形態、蛍光ランプの蛍光体被膜の膜
厚の管理でもって実施できて、既存の蛍光ランプ製造設
備やバックライトユニット組立ラインをそのまま使用で
きる設備投資的に有利なバックライトユニットが提供で
きる。According to the present invention, the brightness at both ends in the lamp array direction on the diffuser plate is surely increased to a value in balance with the brightness at the central part of the diffuser plate, and the brightness uniformity ratio over the entire diffuser plate is increased. It is possible to provide a backlight unit suitable as a backlight for a high-quality liquid crystal display panel by improving and stabilizing. Further, the present invention can be carried out by controlling the wiring form between the fluorescent lamp and the inverter circuit, and the film thickness of the phosphor coating of the fluorescent lamp, and the existing fluorescent lamp manufacturing equipment or equipment that can use the backlight unit assembly line as it is. It is possible to provide a backlight unit that is economically advantageous.
【図１】本発明に係るバックライトユニットの実施例を
示す一部省略部分と部分拡大断面を含む平面図。FIG. 1 is a plan view including a partially omitted portion and a partially enlarged cross section showing an embodiment of a backlight unit according to the present invention.
【図２】図１バックライトユニットの蛍光ランプ端部真
上での輝度分布図。FIG. 2 is a luminance distribution diagram right above an end portion of a fluorescent lamp of the backlight unit.
【図３】図１バックライトユニットの有効発光面を輝度
分布測定のために９等分割したときの平面図。FIG. 3 is a plan view when the effective light emitting surface of the backlight unit is divided into nine equal parts for measuring the luminance distribution.
【図４】従来のバックライトユニットの一部省略部分を
含む平面図。FIG. 4 is a plan view including a partially omitted portion of a conventional backlight unit.
【図５】図４Ａ−Ａ線に沿う断面図。FIG. 5 is a sectional view taken along the line AA of FIG.
【図６】図４バックライトユニットの蛍光ランプ端部真
上での輝度分布図。FIG. 6 is a luminance distribution diagram right above an end portion of the fluorescent lamp of the backlight unit.
１ 反射板 ３ 拡散板 ｍ ランプ空間 ６ Ｕ形蛍光ランプ ６ａ （膜厚大側の）端部 ６ｂ （膜厚小側の）端部 ７ Ｕ形蛍光ランプ ７ａ （膜厚大側の）端部 ７ｂ （膜厚小側の）端部 ６’ ガラス管 ７’ ガラス管 ８ 蛍光体被膜 １１ インバータ回路 １２Ｈ 高電圧側出力端子 １２Ｌ 低電圧側出力端子 DESCRIPTION OF SYMBOLS 1 Reflector 3 Diffuser m Lamp space 6 U-shaped fluorescent lamp 6a End 6b (on the side of large film thickness) End 6b (Small side of the film) End 7 U-shaped fluorescent lamp 7a End 7b (on the side of large film thickness) End part (on the side of small film thickness) 6'Glass tube 7'Glass tube 8 Phosphor coating 11 Inverter circuit 12H High voltage side output terminal 12L Low voltage side output terminal
Claims (4)
なランプ空間に複数のＵ形蛍光ランプを所定間隔で並列
に配置して、各蛍光ランプをインバータ回路で点灯させ
るようにしたバックライトユニットにおいて、 前記インバータ回路は、蛍光ランプの両端部の電極に高
周波電圧を印加して蛍光ランプを高周波点灯させるとき
に、出力電圧がグランドレベルで比較して高圧となる高
電圧側出力端子と低電圧側出力端子を備え、前記ランプ
空間の蛍光ランプ配列方向の両端部に位置する蛍光ラン
プの外側端部の電極をインバータ回路の高電圧側出力端
子に配線したことを特徴とするバックライトユニット。1. A back structure in which a plurality of U-shaped fluorescent lamps are arranged in parallel at a predetermined interval in a flat lamp space formed of a reflecting plate and a transmissive diffusion plate, and each fluorescent lamp is turned on by an inverter circuit. In the light unit, the inverter circuit has a high-voltage side output terminal that has a high output voltage when the high-frequency voltage is applied to the electrodes at both ends of the fluorescent lamp to turn on the fluorescent lamp at a high frequency. A backlight unit having low-voltage output terminals, wherein electrodes at outer ends of the fluorescent lamps located at both ends of the fluorescent lamp in the fluorescent lamp array direction are wired to high-voltage output terminals of an inverter circuit. .
なランプ空間に複数本のＵ形蛍光ランプを所定間隔で並
列に配置して、各蛍光ランプをインバータ回路で点灯さ
せるようにしたバックライトユニットにおいて、 前記複数の各蛍光ランプは、その両端部のガラス管内周
面に形成された蛍光体被膜の膜厚が大小相違し、前記ラ
ンプ空間の蛍光ランプ配列方向の両端部に位置する蛍光
ランプの外側端部が、蛍光体被膜の膜厚大側の端部であ
ることを特徴とするバックライトユニット。2. A plurality of U-shaped fluorescent lamps are arranged in parallel at a predetermined interval in a flat lamp space formed by a reflecting plate and a transmissive diffusion plate, and each fluorescent lamp is turned on by an inverter circuit. In the backlight unit, the plurality of fluorescent lamps are located at both ends in the fluorescent lamp array direction of the lamp space, in which the thicknesses of the phosphor coatings formed on the inner peripheral surfaces of the glass tubes at both ends are different in magnitude. A backlight unit, wherein an outer end portion of the fluorescent lamp is an end portion on the thicker side of the phosphor coating.
なランプ空間に複数本のＵ形蛍光ランプを所定間隔で並
列に配置して、各蛍光ランプをインバータ回路で点灯さ
せるようにしたバックライトユニットにおいて、 前記インバータ回路は、蛍光ランプの両端部の電極に高
周波電圧を印加して蛍光ランプを高周波点灯させるとき
に、出力電圧がグランドレベルで比較して高圧となる高
電圧側出力端子と低電圧側出力端子を備え、前記複数の
各蛍光ランプはその両端部のガラス管内周面に形成され
た蛍光体被膜の膜厚が大小相違し、前記ランプ空間の蛍
光ランプ配列方向の両端部に位置する蛍光ランプの外側
端部が蛍光体被膜の膜厚大側の端部で、かつ、この外側
端部の電極がインバータ回路の高電圧側出力端子に配線
されていることを特徴とするバックライトユニット。3. A plurality of U-shaped fluorescent lamps are arranged in parallel at a predetermined interval in a flat lamp space formed of a reflection plate and a transmissive diffusion plate, and each fluorescent lamp is turned on by an inverter circuit. In the backlight unit, the inverter circuit is a high-voltage side output terminal in which the output voltage becomes high compared to the ground level when a high-frequency voltage is applied to the electrodes at both ends of the fluorescent lamp and the fluorescent lamp is lit at high frequency. And a low-voltage side output terminal, the plurality of fluorescent lamps are different in the thickness of the phosphor coating formed on the inner peripheral surface of the glass tube at both ends thereof, and the fluorescent lamp array direction end portions of the lamp space are different. The outer end of the fluorescent lamp located at is the end on the large film thickness side of the phosphor coating, and the electrode of this outer end is wired to the high voltage side output terminal of the inverter circuit. Backlight unit that.
５ｍｍの冷陰極型蛍光ランプであることを特徴とする請
求項１〜３記載のバックライトユニット。4. A plurality of U-shaped fluorescent lamps having a tube diameter of 2.5 to.
The backlight unit according to claim 1, wherein the backlight unit is a 5 mm cold cathode fluorescent lamp.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6062953A JPH07272507A (en) | 1994-03-31 | 1994-03-31 | Backlight unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6062953A JPH07272507A (en) | 1994-03-31 | 1994-03-31 | Backlight unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07272507A true JPH07272507A (en) | 1995-10-20 |
Family
ID=13215202
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6062953A Withdrawn JPH07272507A (en) | 1994-03-31 | 1994-03-31 | Backlight unit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07272507A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003036703A (en) * | 2001-07-19 | 2003-02-07 | Harison Toshiba Lighting Corp | Lighting device |
| WO2004038283A1 (en) * | 2002-10-22 | 2004-05-06 | Sharp Kabushiki Kaisha | Backlight unit and liquid crystal display unit using backlight unit |
| US6977641B2 (en) | 2002-01-29 | 2005-12-20 | Chi Mei Optoelectronics Corp. | Backlight module and liquid crystal display device |
| JP2007080702A (en) * | 2005-09-15 | 2007-03-29 | Nec Lcd Technologies Ltd | Backlight unit |
| US7234826B2 (en) | 2002-01-29 | 2007-06-26 | Chi Mei Optoelectronics Corp. | Liquid crystal display device and backlight module thereof |
| JP2007287516A (en) * | 2006-04-18 | 2007-11-01 | Iwasaki Electric Co Ltd | Ultraviolet light source body, and ultraviolet irradiation device |
| US7311432B2 (en) | 2005-03-08 | 2007-12-25 | Au Optronics Corp. | Backlight modules and fluorescent lamp assemblies thereof |
| KR100877481B1 (en) * | 2002-09-27 | 2009-01-07 | 엘지디스플레이 주식회사 | Back light unit and liquid crystal display using the same |
| JP2009289752A (en) * | 2007-02-06 | 2009-12-10 | Sharp Corp | Lighting system, display device, and television receiving device |
-
1994
- 1994-03-31 JP JP6062953A patent/JPH07272507A/en not_active Withdrawn
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003036703A (en) * | 2001-07-19 | 2003-02-07 | Harison Toshiba Lighting Corp | Lighting device |
| US6977641B2 (en) | 2002-01-29 | 2005-12-20 | Chi Mei Optoelectronics Corp. | Backlight module and liquid crystal display device |
| US7234826B2 (en) | 2002-01-29 | 2007-06-26 | Chi Mei Optoelectronics Corp. | Liquid crystal display device and backlight module thereof |
| US7583249B2 (en) | 2002-01-29 | 2009-09-01 | Chi Mei Optoelectronics Corp. | Backlight module and liquid crystal display device |
| KR100877481B1 (en) * | 2002-09-27 | 2009-01-07 | 엘지디스플레이 주식회사 | Back light unit and liquid crystal display using the same |
| WO2004038283A1 (en) * | 2002-10-22 | 2004-05-06 | Sharp Kabushiki Kaisha | Backlight unit and liquid crystal display unit using backlight unit |
| US7901103B2 (en) | 2002-10-22 | 2011-03-08 | Sharp Kabushiki Kaisha | Backlight unit and liquid crystal display device using the backlight unit |
| US7455425B2 (en) | 2002-10-22 | 2008-11-25 | Sharp Kabushiki Kaisha | Backlight unit and liquid crystal display device using the backlight unit |
| US7311432B2 (en) | 2005-03-08 | 2007-12-25 | Au Optronics Corp. | Backlight modules and fluorescent lamp assemblies thereof |
| JP2007080702A (en) * | 2005-09-15 | 2007-03-29 | Nec Lcd Technologies Ltd | Backlight unit |
| JP2007287516A (en) * | 2006-04-18 | 2007-11-01 | Iwasaki Electric Co Ltd | Ultraviolet light source body, and ultraviolet irradiation device |
| JP2009289752A (en) * | 2007-02-06 | 2009-12-10 | Sharp Corp | Lighting system, display device, and television receiving device |
| JP4632267B2 (en) * | 2007-02-06 | 2011-02-16 | シャープ株式会社 | Lighting device, display device, and television receiver |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20010605 |