【０００１】[0001]
【発明の属する技術分野】本発明は、蛍光管等のバック
ライトを備える液晶表示装置等の液晶装置に係り、特
に、バックライトの輝度を制御するバックライト制御装
置を備える液晶装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device such as a liquid crystal display device having a backlight such as a fluorescent tube, and more particularly to a liquid crystal device having a backlight control device for controlling the luminance of the backlight.
【０００２】[0002]
【従来の技術】従来、例えば、液晶表示装置において
は、各蛍光管１０ａ乃至１０ｄは、図９にて示すごと
く、液晶パネル２０の裏面に設けた導光板３０の各側縁
に沿い配設されている。これにより、各蛍光管１０ａ乃
至１０ｄは、導光板３０を通して液晶パネル２０を照射
する。2. Description of the Related Art Conventionally, for example, in a liquid crystal display device, each fluorescent tube 10a to 10d is arranged along each side edge of a light guide plate 30 provided on the back surface of a liquid crystal panel 20, as shown in FIG. ing. Thereby, each of the fluorescent tubes 10 a to 10 d irradiates the liquid crystal panel 20 through the light guide plate 30.
【０００３】また、バックライト制御装置は、蛍光管１
０ａ乃至１０ｄの輝度を制御するように、図９及び図１
０にて示すような構成となっている。バックライト制御
装置は、調光機能を有するもので、このバックライト制
御装置の調光方式は自励発振の電源供給を数百ｋＨｚで
断続するバースト方式である。[0003] The backlight control device includes a fluorescent tube 1.
9 and FIG. 1 so as to control the luminance of 0a to 10d.
0. The backlight control device has a light control function, and the light control method of the backlight control device is a burst method in which power supply for self-excited oscillation is intermittently performed at several hundred kHz.
【０００４】このバックライト制御装置は、図９にて示
すごとく、各蛍光管１０ａ乃至１０ｄの輝度をそれぞれ
制御する制御回路Ｅａ乃至Ｅｄを備えている。これら各
制御回路Ｅａ乃至Ｅｄは共に同一の構成を有しているか
ら、制御回路Ｅａの構成について説明する。この制御回
路Ｅａは、図１０にて示すごとく、調光制御回路４０
と、インバータ５０とにより構成されている。As shown in FIG. 9, the backlight control device includes control circuits Ea to Ed for controlling the luminance of the fluorescent tubes 10a to 10d, respectively. Since each of the control circuits Ea to Ed has the same configuration, the configuration of the control circuit Ea will be described. This control circuit Ea includes a dimming control circuit 40 as shown in FIG.
And an inverter 50.
【０００５】調光制御回路４０は、図１１にて示すごと
く、調光制御ＩＣ回路４１と、調光スイッチングトラン
ジスタ４２と、インダクタ４３とにより構成されてい
る。調光制御ＩＣ回路４１は、その入力端子ｉにて、蛍
光管１０ａの輝度を制御する制御信号（図１２（ａ）
（ｂ）にて符号Ａ１、Ａ２参照）を受けて、制御信号電
圧に従うデューティ比のパルス（図１２（ａ）（ｂ）に
て符号Ｂ１、Ｂ２参照）を出力する。As shown in FIG. 11, the dimming control circuit 40 includes a dimming control IC circuit 41, a dimming switching transistor 42, and an inductor 43. The dimming control IC circuit 41 uses a control signal (FIG. 12A) for controlling the luminance of the fluorescent tube 10a at its input terminal i.
In response to (A) and (A2) in (b), a pulse having a duty ratio according to the control signal voltage (B1 and B2 in FIGS. 12A and 12B) is output.
【０００６】調光スイッチングトランジスタ４２は、調
光制御ＩＣ回路４１からのパルスに基づきデューティ制
御されて、バッテリＢａからインダクタ４３への直流電
圧の供給を断続する。インダクタ４３は、調光スイッチ
ングトランジスタ４２により断続的に供給される直流電
圧に基づき、Ｖ＝ωＬＩの実効電圧をインダクタ４３に
供給する。The dimming switching transistor 42 is duty-controlled on the basis of a pulse from the dimming control IC circuit 41 to interrupt the supply of a DC voltage from the battery Ba to the inductor 43. The inductor 43 supplies an effective voltage of V = ωLI to the inductor 43 based on a DC voltage intermittently supplied by the dimming switching transistor 42.
【０００７】また、インバータ５０は、ロイヤー発振回
路５１と、インバータトランス５２と、電流制限用コン
デンサ５３とにより構成されている。ロイヤー発振回路
５１は、インダクタ４３の出力に基づき、回路特性によ
り定まる数十ｋＨｚにて発振する。インバータトランス
５２は、その１次側コイルにて、ロイヤー発振回路５１
の発振出力を受けて、２次側コイルにて、昇圧交流電圧
が発生する。この昇圧交流電圧は、コンデンサ５３を介
し蛍光管１０ａに供給されてこの蛍光管１０ａを調光点
灯する。The inverter 50 includes a lower oscillator circuit 51, an inverter transformer 52, and a current limiting capacitor 53. The lower oscillator circuit 51 oscillates at several tens kHz determined by circuit characteristics based on the output of the inductor 43. The inverter transformer 52 uses the primary coil thereof as the lower oscillator circuit 51.
, The boosted AC voltage is generated in the secondary coil. This boosted AC voltage is supplied to the fluorescent tube 10a via the capacitor 53, and the dimming lighting of the fluorescent tube 10a is performed.
【０００８】ここで、蛍光管１０ａの調光は、設定輝度
に応じて連続的に変化する制御信号（図１２（ａ）
（ｂ）にて符号Ａ１、Ａ２参照）でもって、調光制御Ｉ
Ｃ回路４１の出力パルス（図１２（ａ）（ｂ）にて符号
Ｂ１、Ｂ２参照）のデューティ比を変え、インバータ５
０の実効電圧を変えることによって、発振出力（図１２
（ａ）（ｂ）にて符号Ｃ１、Ｃ２参照）を変化させるこ
とで実現される。Here, the dimming of the fluorescent tube 10a is controlled by a control signal (FIG. 12 (a)) which continuously changes in accordance with the set luminance.
(See symbols A1 and A2 in (b).)
The duty ratio of the output pulse of the C circuit 41 (see reference numerals B1 and B2 in FIGS.
By changing the effective voltage of 0, the oscillation output (FIG. 12)
(See (a) and (b), reference symbols C1 and C2).
【０００９】従って、上記制御信号の電圧レベルによ
り、制御信号電圧が低いときには蛍光管１０ａの管電流
ＩＬが小さく、制御信号電圧が高くなるにつれて管電流
ＩＬが大きくなる。このように、管電流ＩＬの実効値を
変えて蛍光管１０ａの輝度を制御することになる。な
お、他の制御回路Ｅｂ乃至Ｅｄも、入力端子ｉにて上記
制御信号を受けて制御回路Ｅａによる蛍光管１０ａの調
光制御と同様に、他の蛍光管１０ｂ乃至１０ｄの調光制
御を行う。Therefore, depending on the voltage level of the control signal, when the control signal voltage is low, the tube current IL of the fluorescent tube 10a is small, and as the control signal voltage increases, the tube current IL increases. Thus, the luminance of the fluorescent tube 10a is controlled by changing the effective value of the tube current IL. The other control circuits Eb to Ed also receive the control signal at the input terminal i and perform dimming control of the other fluorescent tubes 10b to 10d in the same manner as the dimming control of the fluorescent tube 10a by the control circuit Ea. .
【００１０】[0010]
【発明が解決しようとする課題】ところで、蛍光管１０
ａを例にとって、その輝度の立ち上がり特性について検
討してみると、蛍光管１０ａの輝度は、周囲温度、電極
温度に大きく依存し、管電流ＩＬに応じて通電開始後の
温度上昇カーブが変化し、輝度立ち上がり特性も変わ
る。The fluorescent tube 10
Considering the rise characteristic of the luminance taking the example of a, the luminance of the fluorescent tube 10a greatly depends on the ambient temperature and the electrode temperature, and the temperature rise curve after the start of energization changes according to the tube current IL. , The luminance rise characteristics also change.
【００１１】管電流ＩＬは大きくなる程、蛍光管壁に衝
突するイオンや電子の数も多くなり、蛍光管壁の温度上
昇も速くなるため、蛍光管輝度上昇も速くなる。蛍光管
１０ａの放電電極をヒータで加熱することなく放電を開
始させると、常温の環境下で通電した場合でも、定常な
輝度に達するまで約３分程度の時間を要する。As the tube current IL increases, the number of ions and electrons that collide with the fluorescent tube wall increases, and the temperature of the fluorescent tube wall rises faster, so that the fluorescent tube brightness rises faster. If the discharge is started without heating the discharge electrode of the fluorescent tube 10a with a heater, it takes about 3 minutes to reach a steady luminance even when the electric current is supplied in a normal temperature environment.
【００１２】従って、１０℃以下の低温下で且つ調光状
態で起動するとき、蛍光管１０ａには、定格管電流を下
回る管電流が流れる。このため、輝度の立上がりはさら
に遅くなる。従って、電源投入から液晶パネル２０の画
面輝度が所定の調光輝度に達するまで、画面が暗く、液
晶パネル２０としての十分な表示機能が果たされないこ
とになる。Therefore, when the fluorescent lamp 10a is started at a low temperature of 10 ° C. or less and in a dimming state, a tube current lower than the rated tube current flows through the fluorescent tube 10a. For this reason, the rise of the luminance is further delayed. Therefore, the screen is dark until the screen brightness of the liquid crystal panel 20 reaches the predetermined dimming brightness after the power is turned on, and the sufficient display function as the liquid crystal panel 20 cannot be performed.
【００１３】このように、周囲温度が低い条件下で調光
モードに設定されていると、電源投入直後の数分間は蛍
光管立ち上がり特性に起因して、画面輝度が不十分であ
り視認性を損なうという不具合がある。そこで、本発明
は、このようなことに対処するため、バックライトであ
る放電管の輝度を、低温時の調光設定での電源投入直
後、適正に確保するようにした液晶装置を提供すること
を目的とする。As described above, when the dimming mode is set under the condition where the ambient temperature is low, the screen brightness is insufficient for several minutes immediately after the power is turned on due to the fluorescent tube rising characteristics, and the visibility is poor. There is a problem of damage. In view of the above, the present invention provides a liquid crystal device that appropriately secures the brightness of a discharge tube as a backlight immediately after turning on a power supply in a dimming setting at a low temperature. With the goal.
【００１４】[0014]
【課題を解決するための手段】上記課題の解決にあた
り、請求項１に記載の発明によれば、複数の放電管が、
液晶パネルの裏面に配置した導光板の少なくとも一両対
向側縁に沿い同数ずつ配置されている。また、輝度制御
手段は、複数の放電管の起動時に、温度センサによる液
晶パネルの検出温度が低いときには、上記各同数の放電
管のうちの各一つの放電管に定格管電流或いはこれに近
い管電流を流す。In order to solve the above problems, according to the first aspect of the present invention, a plurality of discharge tubes are provided.
The same number is arranged along at least one opposite side edge of the light guide plate arranged on the back surface of the liquid crystal panel. In addition, when the plurality of discharge tubes are started, when the temperature detected by the temperature sensor of the liquid crystal panel is low, the one or more discharge tubes of the same number of discharge tubes have a rated tube current or a tube close to the rated tube current. Apply current.
【００１５】これにより、定格管電流を流す放電管の温
度上昇が速くなり、この放電管の輝度上昇が速くなる。
また、管電流が定格管電流でない残りの放電管は、定格
管電流を流す放電管の発熱エネルギーを受けて、温度上
昇する。このため、当該残りの放電管の各輝度上昇も速
くなる。As a result, the temperature of the discharge tube through which the rated tube current flows increases rapidly, and the brightness of the discharge tube increases rapidly.
Further, the remaining discharge tubes whose tube currents are not the rated tube current receive the heat generated by the discharge tubes through which the rated tube current flows, and the temperature thereof rises. For this reason, each of the remaining discharge tubes has a faster increase in luminance.
【００１６】よって、液晶パネルの温度が低くても、全
放電管の各輝度が逸速く上昇し、液晶パネルの画面の輝
度を各放電管の起動後逸速く上昇できる。その結果、当
該輝度の立ち上がり時間を短縮し、液晶パネルの画面を
素早く見易い状態にすることができる。この場合、複数
の放電管は、導光板に対し同数ずつ対称的に配置されて
いるから、液晶パネルの輝度は、その全体に亘り均一に
上昇し得る。また、管電流を増大させるのは、一部の放
電管のみであるから、バックライト制御装置における消
費電力の増加が最小限に抑えられる。Therefore, even if the temperature of the liquid crystal panel is low, the brightness of all the discharge tubes rapidly rises, and the brightness of the screen of the liquid crystal panel can rapidly rise after the start of each discharge tube. As a result, the rise time of the luminance can be shortened, and the screen of the liquid crystal panel can be quickly and easily viewed. In this case, since the plurality of discharge tubes are arranged symmetrically by the same number with respect to the light guide plate, the brightness of the liquid crystal panel can uniformly increase over the entirety. Further, since only a part of the discharge tubes increases the tube current, an increase in power consumption in the backlight control device can be minimized.
【００１７】[0017]
【発明の実施の形態】以下、本発明の一実施形態を図１
乃至図３に基づいて説明する。図１は本発明に係る液晶
表示装置を示している。本実施形態では、液晶表示装置
は、図９にて示した各蛍光管１０ａ乃至１０ｄ、液晶パ
ネル２０及び導光板３０を備えている。DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. FIG. 1 shows a liquid crystal display device according to the present invention. In the present embodiment, the liquid crystal display device includes the fluorescent tubes 10a to 10d, the liquid crystal panel 20, and the light guide plate 30 shown in FIG.
【００１８】但し、図９の場合とは異なり、図１及び図
２にて示すごとく、両蛍光管１０ａ及び１０ｂが、導光
板３０の図示右側縁に沿い配設されており、一方、両蛍
光管１０ｃ及び１０ｄが、導光板３０の図示左側縁に沿
い配設されている。なお、図２では、両蛍光管１０ａ及
び１０ｂ及び両蛍光管１０ｃ及び１０ｄが導光板３０と
同一平面上に位置するように示されているが、これは便
宜上のことであり、図２にて示すように、蛍光管１０ａ
及び１０ｃは、それぞれ、蛍光管１０ｂ及び１０ｄの直
上に位置している。However, unlike the case of FIG. 9, as shown in FIGS. 1 and 2, both fluorescent tubes 10a and 10b are arranged along the right side edge of the light guide plate 30 in the drawing. Tubes 10c and 10d are arranged along the left side edge of the light guide plate 30 in the figure. In FIG. 2, both the fluorescent tubes 10 a and 10 b and both the fluorescent tubes 10 c and 10 d are shown to be located on the same plane as the light guide plate 30, but this is for convenience, and FIG. As shown, the fluorescent tube 10a
And 10c are located immediately above the fluorescent tubes 10b and 10d, respectively.
【００１９】また、本実施形態における液晶表示装置は
バックライト制御装置を備えており、このバックライト
制御装置は、図１０の各制御回路Ｅａ乃至Ｅｄに加え、
温度センサ６０及び制御信号出力回路７０を備えてい
る。温度センサ６０は、液晶パネル２０の温度を検出す
る。制御信号出力回路７０は、温度センサ６０の検出温
度に基づき、液晶パネル２０の温度を判定する。The liquid crystal display device according to the present embodiment includes a backlight control device. The backlight control device includes, in addition to the control circuits Ea to Ed shown in FIG.
A temperature sensor 60 and a control signal output circuit 70 are provided. Temperature sensor 60 detects the temperature of liquid crystal panel 20. The control signal output circuit 70 determines the temperature of the liquid crystal panel 20 based on the temperature detected by the temperature sensor 60.
【００２０】そして、この制御信号出力回路７０は、上
記液晶パネル２０の温度判定のもと、調光モード、即ち
蛍光管電流の少ない状態で蛍光管を低温（例えば、１０
℃以下の温度）にて起動する時は、両蛍光管１０ａ、１
０ｃに定格管電流を流すように、制御信号１を各制御回
路Ｅａ、Ｅｃに出力する。このとき、制御信号出力回路
７０は、残りの両蛍光管１０ｂ、１０ｄに指定の調光に
合致する管電流を流すように、制御信号２を各制御回路
Ｅｂ、Ｅｄに出力する。The control signal output circuit 70 sets the temperature of the liquid crystal panel 20 to a dimming mode, that is, a state in which the fluorescent tube current is small, and sets the fluorescent tube to a low temperature (for example, 10
When starting at a temperature of not more than ℃, the fluorescent tubes 10a, 1
The control signal 1 is output to each of the control circuits Ea and Ec so that the rated tube current flows at 0c. At this time, the control signal output circuit 70 outputs the control signal 2 to each of the control circuits Eb and Ed so that a tube current matching the designated dimming flows through the remaining two fluorescent tubes 10b and 10d.
【００２１】このように構成した本実施形態では、温度
センサ６０の検出温度が低いとき、制御信号出力回路７
０は当該検出温度に基づき、上述のように制御信号１を
両制御回路Ｅａ、Ｅｃに出力するとともに、制御信号２
を両制御回路Ｅｂ、Ｅｄに出力する。しかして、両制御
回路Ｅａ、Ｅｃにおいては、調光制御回路４０が、制御
信号１に基づき、インバータ５０が蛍光管１０ａ、１０
ｃに定格管電流を流すように、非調光モードにて調光制
御する。In this embodiment, when the temperature detected by the temperature sensor 60 is low, the control signal output circuit 7
0 outputs the control signal 1 to both control circuits Ea and Ec based on the detected temperature as described above, and outputs the control signal 2
Is output to both control circuits Eb and Ed. Thus, in both control circuits Ea and Ec, the dimming control circuit 40 controls the inverter 50 based on the control signal 1 to switch the fluorescent tubes 10a, 10c.
Dimming control is performed in the non-dimming mode so that the rated tube current flows through c.
【００２２】このため、両制御回路Ｅａ、Ｅｃの各イン
バータ５０が、蛍光管１０ａ、１０ｃに定格管電流を流
す。このことは、蛍光管１０ａ、１０ｃの管電流を増大
することを意味する。その結果、蛍光管１０ａ、１０ｃ
の温度上昇が速くなり、蛍光管１０ａ、１０ｃの輝度上
昇が速くなる。また、両制御回路Ｅｂ、Ｅｄにおいて
は、調光制御回路４０が、制御信号２に基づき、指定の
調光モードに合致する管電流をインバータ５０が蛍光管
１０ｂ、１０ｄに流すように、調光制御する。For this reason, each inverter 50 of both control circuits Ea and Ec allows a rated tube current to flow through the fluorescent tubes 10a and 10c. This means that the tube current of the fluorescent tubes 10a and 10c is increased. As a result, the fluorescent tubes 10a, 10c
And the brightness of the fluorescent tubes 10a and 10c increases quickly. In both control circuits Eb and Ed, the dimming control circuit 40 controls the dimming so that the inverter 50 supplies a tube current matching the designated dimming mode to the fluorescent tubes 10b and 10d based on the control signal 2. Control.
【００２３】このため、両制御回路Ｅｂ、Ｅｄの各イン
バータ５０が、蛍光管１０ｂ、１０ｄに管電流を流す。
この場合、蛍光管１０ａ、１０ｃの管電流の増大により
その発熱量も増大する。従って、これら各蛍光管１０
ａ、１０ｃの発熱エネルギーがそれぞれ各蛍光管１０
ｂ、１０ｄに伝わってこれら蛍光管１０ｂ、１０ｄの温
度をそれぞれ上昇させる。これに伴い、これら蛍光管１
０ｂ、１０ｄの各輝度上昇も速くなる。For this reason, each inverter 50 of both control circuits Eb and Ed supplies a tube current to the fluorescent tubes 10b and 10d.
In this case, the amount of heat generated by the fluorescent lamps 10a and 10c increases due to an increase in the tube current. Therefore, each of these fluorescent tubes 10
a, 10c are generated by the respective fluorescent tubes 10
b, 10d to increase the temperatures of the fluorescent tubes 10b, 10d, respectively. Accordingly, these fluorescent tubes 1
The increase in the brightness of each of 0b and 10d also becomes faster.
【００２４】よって、液晶パネル２０の温度が低くて
も、全蛍光管１０ａ乃至１０ｄの各輝度が逸速く上昇
し、その結果、液晶パネル２０の画面の輝度を各蛍光管
１０ａ乃至１０ｄの起動後逸速く上昇できる。換言すれ
ば、各蛍光管１０ａ乃至１０ｄの起動後液晶パネル２０
が一定温度に達するまでは一部の蛍光管に定格電流を流
すことで、その輝度の立ち上がり時間を短縮し、液晶パ
ネル２０の画面を素早く見易い状態にすることができ
る。Therefore, even if the temperature of the liquid crystal panel 20 is low, the brightness of all the fluorescent tubes 10a to 10d rises rapidly, and as a result, the brightness of the screen of the liquid crystal panel 20 is lost after the activation of each of the fluorescent tubes 10a to 10d. Can climb fast. In other words, after activation of each of the fluorescent tubes 10a to 10d, the liquid crystal panel 20 is activated.
By supplying a rated current to some of the fluorescent tubes until the temperature reaches a certain temperature, the rise time of the luminance can be reduced and the screen of the liquid crystal panel 20 can be quickly and easily viewed.
【００２５】この場合、各蛍光管１０ａ乃至１０ｄは導
光板３０に対し２本ずつ対称的に配置されているから、
液晶パネル１０の輝度はその全体に亘り均一に上昇し得
る。従って、液晶パネル１０の表示面において輝度むら
を招くことがない。また、管電流を増大させるのは、蛍
光管１０ａ、１０ｃのみであるから、バックライト制御
装置における消費電力の増加が最小限に抑えられる。In this case, since each of the fluorescent tubes 10a to 10d is symmetrically arranged two by two with respect to the light guide plate 30,
The brightness of the liquid crystal panel 10 can be uniformly increased over the whole. Therefore, the display surface of the liquid crystal panel 10 does not have uneven brightness. Further, since only the fluorescent tubes 10a and 10c increase the tube current, an increase in power consumption in the backlight control device can be minimized.
【００２６】また、以上の作用効果は、特に、液晶パネ
ル２０が大型パネルである場合に、その複数の蛍光管の
低温時起動後の輝度立ち上がり特性改善に著しい。な
お、液晶パネル２０が規定温度に達した後は、図１０に
ついて述べたと同様の調光制御が行われる。この場合、
各蛍光管１０ａ、１０ｃの輝度が両制御回路Ｅａ、Ｅｃ
の各調光制御回路４０における設定輝度に応じた調光制
御のもと、徐々に（例えば、２分乃至１５分程度の間
に）減少するようにする。The above-mentioned effects are particularly remarkable in improving the luminance rise characteristics of the plurality of fluorescent tubes after starting at low temperatures when the liquid crystal panel 20 is a large panel. After the liquid crystal panel 20 reaches the specified temperature, the same dimming control as described with reference to FIG. 10 is performed. in this case,
The brightness of each of the fluorescent tubes 10a and 10c is controlled by both control circuits Ea and Ec.
Under the dimming control corresponding to the set luminance in each dimming control circuit 40, the dimming is gradually (for example, about 2 to 15 minutes).
【００２７】従って、定格管電流を両蛍光管１０ａ、１
０ｃに常時流すこともないので、蛍光管寿命の低下や消
費電力の増加を最小限に抑制できる。また、図４及び図
５は、上記実施形態の第１変形例の要部を示している。
この第１変形例では、上記実施形態とは異なり、両蛍光
管１０ａ、１０ｃが導光板３０の上側縁に沿い配設され
るとともに、両蛍光管１０ｂ、１０ｄが導光板３０の下
側縁に沿い配設されている。Accordingly, the rated tube current is reduced by the two fluorescent tubes 10a, 1
Since the current does not always flow at 0c, a reduction in the life of the fluorescent tube and an increase in power consumption can be suppressed to a minimum. FIGS. 4 and 5 show a main part of a first modification of the above embodiment.
In the first modification, unlike the above embodiment, both fluorescent tubes 10a and 10c are disposed along the upper edge of the light guide plate 30, and both fluorescent tubes 10b and 10d are located at the lower edge of the light guide plate 30. It is arranged along.
【００２８】なお、図４では、両蛍光管１０ａ及び１０
ｂ及び両蛍光管１０ｃ及び１０ｄが導光板３０と同一平
面上に位置するように示されているが、これは便宜上の
ことであり、図５にて示すように、蛍光管１０ａ及び１
０ｃは、それぞれ、蛍光管１０ｂ及び１０ｄの直上に位
置している。その他の構成は上記実施形態と同様であ
る。FIG. 4 shows both fluorescent tubes 10a and 10a.
b and both fluorescent tubes 10c and 10d are shown as being located on the same plane as the light guide plate 30, but this is for convenience and as shown in FIG.
0c is located immediately above the fluorescent tubes 10b and 10d, respectively. Other configurations are the same as those of the above embodiment.
【００２９】これによっても、上記実施形態と同様の作
用効果を達成できる。また、図６乃至図８は、上記実施
形態の第２変形例の要部を示している。この第２変形例
では、上記実施形態にて述べた両蛍光管１０ａ、１０ｃ
及び両蛍光管１０ｂ、１０ｄに加え、他の両蛍光管１０
ａ、１０ｃが導光板３０の上側縁に沿い配設されるとと
もに、他の両蛍光管１０ｂ、１０ｄが導光板３０の下側
縁に沿い配設されている。According to this, the same operation and effect as the above embodiment can be achieved. 6 to 8 show a main part of a second modification of the above embodiment. In the second modified example, the fluorescent tubes 10a and 10c described in the above embodiment are used.
In addition to the two fluorescent tubes 10b and 10d, the other two fluorescent tubes 10
a and 10c are arranged along the upper edge of the light guide plate 30, and the other two fluorescent tubes 10b and 10d are arranged along the lower edge of the light guide plate 30.
【００３０】また、他の両蛍光管１０ａ、１０ｃは、両
制御回路Ｅａ、Ｅｃと同様の両制御回路によりそれぞれ
制御され、他の両蛍光管１０ｂ、１０ｄは、両制御回路
Ｅｂ、Ｅｄと同様の両制御回路によりそれぞれ制御され
る。なお、各蛍光管１０ａ乃至１０ｄの導光板３０に対
する配設位置は、第１変形例と同様である。その他の構
成は上記実施形態と同様である。The other two fluorescent tubes 10a and 10c are respectively controlled by two control circuits similar to the two control circuits Ea and Ec, and the other two fluorescent tubes 10b and 10d are similar to both control circuits Eb and Ed. , Respectively. The arrangement positions of the fluorescent tubes 10a to 10d with respect to the light guide plate 30 are the same as in the first modification. Other configurations are the same as those of the above embodiment.
【００３１】これにより、上記実施形態にて述べた作用
効果をより一層向上できる。本発明の実施にあたって
は、上記実施形態のように温度センサ６０の検出温度に
応じて制御信号１を制御するのではなく、検出温度が低
いとき、例えば、両蛍光管１０ａ、１０ｃに対し、一定
時間或いは任意の設定時間の間、定格管電流を流すよう
にしてもよい。Thus, the function and effect described in the above embodiment can be further improved. In practicing the present invention, instead of controlling the control signal 1 in accordance with the temperature detected by the temperature sensor 60 as in the above-described embodiment, when the detected temperature is low, for example, a fixed value is applied to both the fluorescent tubes 10a and 10c. The rated tube current may flow during the time or an arbitrary set time.
【００３２】また、上記実施形態では、低温時に両蛍光
管１０ａ、１０ｃに流す電流を定格管電流としたが、こ
れに代えて、定格管電流±２０％程度の管電流を流すよ
うにしてもよい。また、本発明の実施にあたり、蛍光管
１０ａ乃至１０ｄに限ることなく、一般に、放電管を採
用してもよい。In the above embodiment, the current flowing through the fluorescent tubes 10a and 10c at the time of low temperature is the rated tube current. Good. Further, in carrying out the present invention, a discharge tube may be generally adopted without being limited to the fluorescent tubes 10a to 10d.
【００３３】また、本発明の実施にあたり、導光板３０
の一側縁に沿い配置する蛍光管の数は２本に限ることな
く、１本或いは３本以上であってもよい。また、本発明
の実施にあたっては、液晶表示装置に限ることなく、液
晶スイッチ等の各種の液晶装置の複数の蛍光管を起動す
るに際し本発明を適用してもよい。In implementing the present invention, the light guide plate 30
The number of fluorescent tubes arranged along one side edge is not limited to two, and may be one or three or more. In practicing the present invention, the present invention is not limited to a liquid crystal display device, but may be applied to the activation of a plurality of fluorescent tubes of various liquid crystal devices such as a liquid crystal switch.
【図１】本発の一実施形態を示す概略全体構成図であ
る。FIG. 1 is a schematic overall configuration diagram showing an embodiment of the present invention.
【図２】図１にて２−２線に沿う断面図である。FIG. 2 is a sectional view taken along line 2-2 in FIG.
【図３】図１の各蛍光管の輝度を制御するためのバック
ライト制御回路図である。FIG. 3 is a backlight control circuit diagram for controlling the luminance of each fluorescent tube of FIG. 1;
【図４】上記実施形態の第１変形例を示す要部平面図で
ある。FIG. 4 is a main part plan view showing a first modification of the embodiment.
【図５】図４にて５−５線に沿う断面図である。FIG. 5 is a sectional view taken along line 5-5 in FIG.
【図６】上記実施形態の第２変形例を示す要部平面図で
ある。FIG. 6 is a main part plan view showing a second modification of the above embodiment.
【図７】図６にて７−７線に沿う断面図である。FIG. 7 is a sectional view taken along line 7-7 in FIG.
【図８】図６にて８−８線に沿う断面図である。FIG. 8 is a sectional view taken along line 8-8 in FIG.
【図９】従来の液晶表示装置の概略構成図である。FIG. 9 is a schematic configuration diagram of a conventional liquid crystal display device.
【図１０】図９のバックライト制御装置の各制御回路Ｅ
ａ乃至Ｅｄの詳細回路図である。10 shows each control circuit E of the backlight control device of FIG. 9;
It is a detailed circuit diagram of a to Ed.
【図１１】図１０の各制御回路Ｅａ乃至Ｅｄの詳細回路
図である。11 is a detailed circuit diagram of each of the control circuits Ea to Ed of FIG.
【図１２】図１１の主要構成素子の入出力を表すタイミ
ングチャートである。FIG. 12 is a timing chart showing input and output of the main constituent elements of FIG.
１０ａ乃至１０ｄ…蛍光管、２０…液晶パネル、３０…
導光板、６０…温度センサ、７０…制御信号出力回路、
Ｅａ乃至Ｅｄ…制御回路。10a to 10d: fluorescent tube, 20: liquid crystal panel, 30 ...
Light guide plate, 60 temperature sensor, 70 control signal output circuit,
Ea to Ed: control circuits.
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9196044AJPH1138381A (en) | 1997-07-22 | 1997-07-22 | Liquid crystal device |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9196044AJPH1138381A (en) | 1997-07-22 | 1997-07-22 | Liquid crystal device |
| Publication Number | Publication Date |
|---|---|
| JPH1138381Atrue JPH1138381A (en) | 1999-02-12 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9196044APendingJPH1138381A (en) | 1997-07-22 | 1997-07-22 | Liquid crystal device |
| Country | Link |
|---|---|
| JP (1) | JPH1138381A (en) |
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