JP2005084354A

JP2005084354A - Liquid crystal display device

Info

Publication number: JP2005084354A
Application number: JP2003316290A
Authority: JP
Inventors: Mitsuo Nakayama; 三男中山
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2003-09-09
Filing date: 2003-09-09
Publication date: 2005-03-31
Anticipated expiration: 2023-09-09
Also published as: JP4294423B2

Abstract

<P>PROBLEM TO BE SOLVED: To increase the size of a liquid crystal display device without attaching a fan thereto by discharging generated heat with natural convection. <P>SOLUTION: In the liquid crystal display device comprising a liquid crystal panel 5 irradiated with light from a direct backlight and housed in the front section of a cabinet 6 and a circuit substrate 71 disposed on the rear face of a reflection plate 2 of the direct backlight and having ventilating holes 61 and 62 formed on the rear lower and upper faces of the cabinet 6, the liquid crystal display device is characterized by disposing the circuit substrate 71 on the rear face side of the reflection plate 2 nearly in parallel with the reflection plate 2 so as to keep a distance sufficient to generate the natural convection therethrough and making clearance between the circuit substrate 71 and the rear face side wall 63 of the cabinet 6 have a distance sufficient to generate the natural convection therethrough. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、大型液晶テレビ等の直下型バックライトを有する液晶表示装置に関し、詳しくは、液晶表示装置のバックライトの背面の回路基板の取付け部をいわゆる煙突構造として、バックライトおよび回路基板の発熱を自然対流により効率良く排出するようにした液晶表示装置に関する。 The present invention relates to a liquid crystal display device having a direct type backlight such as a large-sized liquid crystal television, and more specifically, the mounting portion of the circuit board on the back of the backlight of the liquid crystal display device has a so-called chimney structure, and the heat generation of the backlight and the circuit board. The present invention relates to a liquid crystal display device that efficiently discharges water by natural convection.

従来、直下型バックライトを有する液晶テレビは、図６のように構成されている。図において、６はキャビネットであり、その前面に液晶パネル５が配置され、その後方に光学シート４、拡散板３、ランプ１、バックライト反射板２が配置されている。さらに、バックライト反射板２の背面には、回路基板７６が取付けられている。この液晶テレビの作動時は、ランプ１および回路基板７６の発熱により、バックライト反射板２の背面空間の温度が上昇する。すると、矢印に示すような自然対流が発生し、キャビネット６の下部に形成された孔６１から空気が供給されて上部の孔６２から排出される。ここでバックライト反射板２と背面の回路基板７６とは近接して取り付けられるため、バックライト反射板２の背面側と回路基板７６との間で、上方向には排熱気流が流れにくいという課題があった。ところで、近年、液晶テレビは大型化しつつあり、その大型化に伴い、バックライトの発熱量と回路基板の発熱量が増大し、それらの発熱を効率よく排出することが課題となっていた。 Conventionally, a liquid crystal television having a direct backlight is configured as shown in FIG. In the figure, reference numeral 6 denotes a cabinet, in which a liquid crystal panel 5 is arranged on the front surface, and an optical sheet 4, a diffusion plate 3, a lamp 1, and a backlight reflecting plate 2 are arranged behind the cabinet. Further, a circuit board 76 is attached to the back surface of the backlight reflector 2. During operation of the liquid crystal television, the temperature of the back space of the backlight reflector 2 rises due to heat generated by the lamp 1 and the circuit board 76. Then, natural convection as shown by an arrow occurs, air is supplied from the hole 61 formed in the lower part of the cabinet 6, and is discharged from the upper hole 62. Here, since the backlight reflector 2 and the circuit board 76 on the back are attached close to each other, it is difficult for the exhaust heat flow to flow upward between the back of the backlight reflector 2 and the circuit board 76. There was a problem. By the way, in recent years, the size of liquid crystal televisions has been increasing, and along with the increase in size, the amount of heat generated by the backlight and the amount of heat generated by the circuit board have increased, and there has been a problem of efficiently discharging the generated heat.

これは、液晶テレビに限らずＥＬ表示装置、ＰＤＰ装置等でも同様な課題であった。その課題を解決するための従来技術として、特許文献１および特許文献２等が知られている。特許文献１は、表示パネル１の背面に冷却空気の通路となる所定の間隙を形成する支持体７を介して仕切り板３３を配置し、この間隙を上昇通過する空気により表示パネル１を冷却するよう構成したものである。また、表示パネル１の背面に熱伝導部材を介して前記間隙内に冷却フィンを取り付けることによりさらに冷却特性を向上させる手段も開示されている。 This is the same problem not only in liquid crystal televisions but also in EL display devices, PDP devices, and the like. As conventional techniques for solving the problem, Patent Document 1, Patent Document 2, and the like are known. In Patent Document 1, a partition plate 33 is disposed on a back surface of the display panel 1 via a support 7 that forms a predetermined gap serving as a cooling air passage, and the display panel 1 is cooled by air that passes through the gap. It is comprised as follows. Also disclosed is a means for further improving the cooling characteristics by attaching a cooling fin in the gap to the back surface of the display panel 1 via a heat conducting member.

また、特許文献２は、閉塞された空間に配置した液晶パネル表示面から発生する熱を筐体の外部に放熱する手段として、回路基板２５２と液晶パネル２５６とで構成される表示部１２４を縦置き状態でゲージ部１１４に取り付けた際、センター装飾部材２５０の保護カバー２６８によって閉塞状態となる液晶パネル２５６の表示面前方の雰囲気を、前記基板２５２の上端部に設けた排熱ファン２７６によって、導路２７２を介して導き、ケース２６０外に排出するようにした。またここでは、意図的に仕切板２７４及びリブ２７４Ａによって電子部品から発する熱が空間部２７０へ来ないようにした放熱手段が開示されている。
特開２０００−８９６８２号公報特開２００２−４５５３０号公報 Patent Document 2 discloses that a display unit 124 composed of a circuit board 252 and a liquid crystal panel 256 is vertically used as a means for radiating heat generated from a liquid crystal panel display surface arranged in a closed space to the outside of the housing. When attached to the gauge unit 114 in a placed state, the atmosphere in front of the display surface of the liquid crystal panel 256 that is closed by the protective cover 268 of the center decorative member 250 is caused by the heat exhaust fan 276 provided at the upper end of the substrate 252. It was guided through the guiding path 272 and discharged out of the case 260. Further, here, a heat radiating means is disclosed in which heat generated from the electronic component is intentionally prevented from reaching the space portion 270 by the partition plate 274 and the rib 274A.
JP 2000-89682 A JP 2002-45530 A

しかしながら、特許文献１は、表示パネル１の背面に冷却空気の通路となる所定の間隙を形成する支持体７を介して表示パネルと略同じ大きさのアルミ製仕切り板３３を配置し、この間隙を上昇通過する空気により表示パネル１を冷却するよう構成されているが、複数の電気回路基板が仕切り板３３の背面上のほぼ全体の表面にわたって一様に配置されているので、該仕切り板３３の下方向に配置されている回路基板から発生する熱量（温度）と該仕切り板３３の上方向に配置されている回路基板の熱量（温度）とが均衡し、仕切り板３３の背面において、下部と上部の温度差が小さいために通路空間において、下部から上部方向へ冷却空気が流れにくく放熱効果が悪いという問題があった。そこで、冷却効果を向上するためには、冷却空気が一定以上の流速をもつことが必用であるが、下部から上部方向へ一定以上の流速を得るためには上部に放熱用のファン等が必要になる課題を有していた。このため、特許文献１に記載のように、表示パネル１の背面に熱伝導部材を設けてアルミニウム製の冷却フィンを取り付けなければならない課題を有していた。 However, in Patent Document 1, an aluminum partition plate 33 having a size substantially the same as that of the display panel is disposed on the back surface of the display panel 1 via a support 7 that forms a predetermined gap serving as a cooling air passage. The display panel 1 is cooled by the air that passes upward through the screen. However, since the plurality of electric circuit boards are arranged uniformly over substantially the entire surface of the rear surface of the partition plate 33, the partition plate 33 is provided. The amount of heat (temperature) generated from the circuit board arranged in the downward direction and the amount of heat (temperature) of the circuit board arranged in the upward direction of the partition plate 33 are balanced, and Since the temperature difference between the upper part and the upper part is small, there is a problem that in the passage space, the cooling air hardly flows from the lower part to the upper part and the heat dissipation effect is poor. Therefore, in order to improve the cooling effect, it is necessary that the cooling air has a flow rate above a certain level, but in order to obtain a flow rate above a certain level from the lower part to the upper part, a heat dissipation fan or the like is necessary at the upper part. Had a problem to become. For this reason, as described in Patent Document 1, there is a problem that a heat conductive member is provided on the back surface of the display panel 1 and aluminum cooling fins must be attached.

また、特許文献２では、液晶パネル２５６からの放熱用に機器の上部に排熱ファンが必要になると共に、回路基板２５２の背面に電子部品が下部から上部にわたって配置されているために電子部品側の空間において下部と上部で発生する熱量差（温度差）が生じにくく、特許文献１の場合と同様に放熱効果が悪い問題を有していた。特に大型表示装置では必然的にパネルや回路部品からの発熱量が大きくなるが、特に表示装置の下部と上部方向とでより大きな温度差を実現しないと冷却空気の流速を大きくできず放熱効果の向上が難しい課題があった。
そこで、本発明は、回路基板の上部と下部とに温度差を設けるようにして放熱効果を増大することを目的とした。 In Patent Document 2, a heat exhaust fan is required at the top of the device for heat dissipation from the liquid crystal panel 256, and the electronic component is disposed on the back side of the circuit board 252 from the bottom to the top. In this space, the difference in heat quantity (temperature difference) generated between the lower part and the upper part hardly occurs, and the heat dissipation effect is poor as in the case of Patent Document 1. Particularly in large display devices, the amount of heat generated from the panel and circuit components inevitably increases.However, unless a larger temperature difference is realized between the lower and upper parts of the display device, the cooling air flow rate cannot be increased and the heat dissipation effect is reduced. There were issues that were difficult to improve.
Accordingly, an object of the present invention is to increase the heat dissipation effect by providing a temperature difference between the upper part and the lower part of the circuit board.

上記課題を解決するために、本発明は、キャビネット前部に直下型バツクライトにより照射される液晶パネルを収納し、前記直下型バツクライトの反射板の背面に回路基板を配設し、前記キャビネット後部の下面および上面に通風手段を形成した液晶表示装置において、前記反射板の背面に前記回路基板を前記反射板と略並行に配設するとともに、前記反射板と前記回路基板との間を自然対流が発生する間隔としたことを特徴とする。また、本発明は、前記回路基板と前記キャビネットの背面側壁との間を自然対流が発生する間隔としたことを特徴とする。また、本発明は、前記回路基板の縦寸法が前記反射板の背面高さ寸法に満たない場合は、前記回路基板を下寄りに配置し、その上方の高さ寸法に満たない部分に補助仕切り板を前記回路基板に連続させて設けたことを特徴とする。ここで、前記回路基板が複数ある場合は、縦寸法が前記反射板の背面高さ寸法に満たない回路基板についてのみ下寄りに配置し、その上方の高さ寸法に満たない部分に補助仕切り板を前記回路基板に連続させて設ける。また、本発明は、前記各回路基板および前記各補助仕切り板をそれぞれ垂直方向のリブを介して前記反射板の背面に取り付けたことを特徴とする。また、本発明は、前記各回路基板のそれぞれの発熱量の値が左右対称またはそれに近い配置となるように前記各回路基板を配置したことを特徴とする。また、本発明は、前記各回路基板のそれぞれの発熱量の値が左右均等またはそれに近い配置となるように前記各回路基板を配置したことを特徴とする。また、本発明は、前記回路基板として２個の点灯回路用インバータ基板がある場合は、それらを左右両端に配置したことを特徴とする。 In order to solve the above problems, the present invention accommodates a liquid crystal panel irradiated with a direct backlight in a front part of a cabinet, a circuit board is disposed on a back surface of a reflector of the direct backlight, In the liquid crystal display device in which ventilation means are formed on the lower surface and the upper surface, the circuit board is disposed on the back surface of the reflecting plate substantially in parallel with the reflecting plate, and natural convection occurs between the reflecting plate and the circuit board. It is characterized by the occurrence interval. Further, the present invention is characterized in that a natural convection is generated between the circuit board and the back side wall of the cabinet. Further, according to the present invention, when the vertical dimension of the circuit board is less than the height of the back surface of the reflector, the circuit board is disposed on the lower side, and the auxiliary partition is formed in a portion less than the height dimension above the circuit board. A board is provided continuously with the circuit board. Here, when there are a plurality of the circuit boards, the circuit board is arranged below only the circuit board whose vertical dimension is less than the height of the back surface of the reflecting plate, and the auxiliary partition plate is provided in a part that is less than the height dimension above the circuit board. Are continuously provided on the circuit board. Further, the present invention is characterized in that each of the circuit boards and each of the auxiliary partition plates is attached to the back surface of the reflecting plate through a vertical rib. Further, the present invention is characterized in that the circuit boards are arranged so that the respective calorific values of the circuit boards are symmetrical or close to each other. In addition, the present invention is characterized in that the circuit boards are arranged so that the respective calorific values of the circuit boards are arranged to be equal to or close to the left and right. Further, according to the present invention, when there are two lighting circuit inverter boards as the circuit board, they are arranged at both left and right ends.

以上述べたように本発明によれば、直下型バツクライトの反射板の背面に回路基板を前記反射板と略並行に配設し、反射板と回路基板との間を自然対流が発生する間隔とするとともに、回路基板が複数あってそれらの縦寸法が反射板の背面高さ寸法に満たない場合は、各回路基板を下寄りに配置し、それらの上方の高さ寸法に満たない部分にそれぞれ補助仕切り板を前記各回路基板に連続させて設けたことでいわゆる煙突構造が形成され、熱源である回路基板が下寄りに配置されたことで、煙突構造の下部が上部よりも高温となり、煙突構造により発生する自然対流の勢いが増大される。その結果、液晶表示装置における発生熱を自然対流により排出することが可能となり、液晶表示装置が大型化された場合も、熱排出に関しては、ファンを設置することなく、対応可能となる。 As described above, according to the present invention, the circuit board is disposed substantially in parallel with the reflecting plate on the back surface of the reflecting plate of the direct type backlight, and the natural convection is generated between the reflecting plate and the circuit board. In addition, if there are multiple circuit boards and their vertical dimensions are less than the height of the back surface of the reflector, each circuit board is placed on the lower side, and the parts below the height dimensions above them are respectively The so-called chimney structure is formed by providing the auxiliary partition plate continuously with each circuit board, and the lower part of the chimney structure becomes hotter than the upper part because the circuit board as the heat source is arranged on the lower side. The momentum of natural convection generated by the structure is increased. As a result, the heat generated in the liquid crystal display device can be discharged by natural convection, and even when the liquid crystal display device is enlarged, the heat discharge can be handled without installing a fan.

以下、図に基づいて本発明の実施形態を説明する。
図１は本発明に係る液晶表示装置の第１の実施形態を示す縦断面図であり、図２は図１の背面の回路基板の配置を示す配置図であり、図３は図１の横断面図であり、図４は図３の要部を拡大して示した図である。これらの図において、６はキャビネットであり、その前面に液晶パネル５が配置され、その後方に光学シート４、拡散板３、ランプ１、バックライト反射板２が配置されている。さらに、バックライト反射板２の背面の下寄りには、煙突効果を発揮するに最適な５〜１０ｍｍの間隔をおいて回路基板７１、インバータ基板７２、映像基板７３、音声基板７４が取付けられている。さらに回路基板７１、映像基板７３、音声基板７４の上端には、ポリカーボネイトからなる補助仕切り板８１〜８３がそれぞれ接続されている。これら補助仕切り板８１〜８３は、バックライト反射板２の背面にリブ９１を介して支持されており、バックライト反射板２の背面と５〜１０ｍｍの間隔をおいて、バックライト反射板２の上端部まで支持されている。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a liquid crystal display device according to the present invention, FIG. 2 is a layout view showing the layout of a circuit board on the back of FIG. 1, and FIG. 3 is a cross-sectional view of FIG. FIG. 4 is an enlarged view of the main part of FIG. In these drawings, reference numeral 6 denotes a cabinet, in which a liquid crystal panel 5 is disposed on the front surface, and an optical sheet 4, a diffusion plate 3, a lamp 1, and a backlight reflecting plate 2 are disposed on the rear side. Further, a circuit board 71, an inverter board 72, a video board 73, and an audio board 74 are attached to the lower side of the back surface of the backlight reflector 2 at intervals of 5 to 10 mm which are optimal for exhibiting the chimney effect. Yes. Further, auxiliary partition plates 81 to 83 made of polycarbonate are connected to upper ends of the circuit board 71, the video board 73, and the audio board 74, respectively. These auxiliary partition plates 81 to 83 are supported on the back surface of the backlight reflection plate 2 via ribs 91, and are spaced from the back surface of the backlight reflection plate 2 by a distance of 5 to 10 mm. It is supported to the upper end.

この液晶表示装置の作動時は、ランプ１および回路基板７１、インバータ基板７２、映像基板７３、音声基板７４が発熱して、バックライト反射板２の背面および各基板７１〜７４の両面が温度上昇する。すると、それらの表面の暖められた空気は、比重が小さくなり上昇を開始し、図１の矢印に示すような自然対流が発生する。その結果、キャビネット６の下部に形成された孔６１から空気が供給されて上部の孔６２から排出される。また、このとき、バックライト反射板２の背面と各基板７１〜７４および補助仕切り板８１〜８３の間は、煙突効果を発揮するに最適な間隔であるため、その間を通過する空気は、加速されて上昇する。また、各基板７１〜７４および補助仕切り板８１〜８３とキャビネット６の背面側壁６３との間も、同様に、幅の狭い空間であるため、煙突効果により上昇気流を発生して、暖められた空気を上方に排気して、冷えた外気を下方より吸い込む。なお、各基板７１〜７４および補助仕切り板８１〜８３の互いに接する縁の部分は、隙間がない方が煙突効果が著しいので、可能な限り近づけるように配置する。 During the operation of the liquid crystal display device, the lamp 1, the circuit board 71, the inverter board 72, the video board 73, and the audio board 74 generate heat, and the back surface of the backlight reflector 2 and both surfaces of the boards 71 to 74 rise in temperature. To do. As a result, the heated air on the surfaces has a reduced specific gravity and starts to rise, and natural convection as shown by the arrows in FIG. 1 occurs. As a result, air is supplied from the hole 61 formed in the lower part of the cabinet 6 and discharged from the upper hole 62. At this time, the space between the back surface of the backlight reflector 2 and each of the substrates 71 to 74 and the auxiliary partition plates 81 to 83 is an optimal interval for exhibiting the chimney effect. To rise. Similarly, the space between each of the substrates 71 to 74 and the auxiliary partition plates 81 to 83 and the rear side wall 63 of the cabinet 6 is also a narrow space. The air is exhausted upward, and cold outside air is sucked from below. Note that the edge portions of the substrates 71 to 74 and the auxiliary partition plates 81 to 83 that are in contact with each other are arranged so as to be as close as possible because the chimney effect is remarkable when there is no gap.

この液晶表示装置では、ランプ１を点灯するためのインバータ基板７２が２枚あり、これらは基板７１〜７４の中で最も発熱量が大きいため、左右の両端に配置した。残りの基板７１、７３、７４については、その発熱量に応じて、その発熱量が左右対称または左右均等に近い状態になるように配置した。また、基板７１、７３、７４については、下方寄りに配置してインバータ基板７２の下端に揃え、その上方の空いた部分に補助仕切り板８１〜８３を接続するようにして、発熱部が煙突構造の下部となり煙突構造の下部がその上部よりも高温になるようにして、煙突構造部で発生する上昇気流の勢いが増大されるようにした。またその結果、各基板７１〜７４ごとに煙突構造が形成され、各基板７１〜７４の発生熱量が横移動することなく、そのまま上昇して排出されるようになる。 In this liquid crystal display device, there are two inverter boards 72 for turning on the lamp 1, and these are the heat generation amount among the boards 71 to 74, so they are arranged at the left and right ends. The remaining substrates 71, 73, and 74 are arranged so that the heat generation amount is symmetrical or close to the left and right according to the heat generation amount. Moreover, about board | substrate 71,73,74, it arrange | positions in the downward direction, aligns with the lower end of the inverter board | substrate 72, and connects the auxiliary partition plates 81-83 to the vacant part of the upper part, and a heat generating part has a chimney structure. The lower part of the chimney structure becomes a higher temperature than the upper part of the chimney structure so that the momentum of the updraft generated in the chimney structure part is increased. As a result, a chimney structure is formed for each of the substrates 71 to 74, and the generated heat amount of each of the substrates 71 to 74 rises and is discharged as it is without lateral movement.

図５は本発明に係る液晶表示装置の第２の実施形態を示す縦断面図である。図において、６はキャビネットであり、その前面に液晶パネル５が配置され、その後方に光学シート４、拡散板３、ランプ１、バックライト反射板２が配置されている。さらに、バックライト反射板２の背面の下寄りには、煙突効果を発揮するに最適な５〜１０ｍｍの間隔をおいて回路基板７１が取付けられている。この液晶表示装置の作動時は、ランプ１および回路基板７１が発熱して、バックライト反射板２の背面および回路基板７１の両面が温度上昇する。 FIG. 5 is a longitudinal sectional view showing a second embodiment of the liquid crystal display device according to the present invention. In the figure, reference numeral 6 denotes a cabinet, in which a liquid crystal panel 5 is arranged on the front surface, and an optical sheet 4, a diffusion plate 3, a lamp 1, and a backlight reflecting plate 2 are arranged behind the cabinet. Furthermore, a circuit board 71 is attached to the lower side of the back surface of the backlight reflecting plate 2 with an interval of 5 to 10 mm which is optimal for exhibiting the chimney effect. During operation of the liquid crystal display device, the lamp 1 and the circuit board 71 generate heat, and the temperature of the back surface of the backlight reflector 2 and both surfaces of the circuit board 71 rises.

すると、それらの表面の暖められた空気は、比重が小さくなり上昇を開始し、矢印に示すような自然対流が発生する。その結果、キャビネット６の下部に形成された孔６１から空気が供給されて上部の孔６２から排出される。また、このとき、バックライト反射板２の背面と回路基板７１の間は、煙突効果を発揮するに最適な間隔であるため、その間を通過する空気は、加速されて上昇する。なお、回路基板７１とキャビネット６の背面側壁６３との間も、同様に、幅の狭い空間であるため、煙突効果により上昇気流を発生して、暖められた空気を上方に排気して、冷えた外気を下方より吸い込む。 Then, the warmed air of those surfaces starts to rise due to a decrease in specific gravity, and natural convection as shown by the arrows occurs. As a result, air is supplied from the hole 61 formed in the lower part of the cabinet 6 and discharged from the upper hole 62. At this time, the distance between the back surface of the backlight reflector 2 and the circuit board 71 is an optimum distance for exhibiting the chimney effect, so that the air passing therebetween is accelerated and rises. Similarly, since the space between the circuit board 71 and the rear side wall 63 of the cabinet 6 is also a narrow space, an upward airflow is generated by the chimney effect, and the warmed air is exhausted upward to cool down. Inhale outside air from below.

このように構成したことで、本発明の液晶表示装置では、自然対流のみにより発生熱を外部に排出することが可能となり、大型化された場合も、騒音、振動や埃の問題を発生する排気ファンの取付けが不要となる。なお、自然対流による冷却を補完する目的で、キャビネット６の上下部に形成された孔６１，６２の近くに小容量のファンを設けることも可能である。 With such a configuration, in the liquid crystal display device of the present invention, it is possible to discharge generated heat only by natural convection, and even when the size is increased, exhaust that generates noise, vibration and dust problems. No fan installation is required. For the purpose of complementing the cooling by natural convection, it is possible to provide a small capacity fan near the holes 61 and 62 formed in the upper and lower portions of the cabinet 6.

本発明は、液晶テレビ等の液晶表示装置以外には、発熱する表示パネルを有するＥＬ表示装置、ＰＤＰ等にも利用可能である。 The present invention can be applied to an EL display device having a display panel that generates heat, a PDP, and the like in addition to a liquid crystal display device such as a liquid crystal television.

本発明に係る液晶表示装置の第１の実施形態を示す縦断面図である。1 is a longitudinal sectional view showing a first embodiment of a liquid crystal display device according to the present invention. 図１の背面の回路基板の配置を示す配置図である。FIG. 2 is a layout diagram illustrating a layout of a circuit board on the back surface of FIG. 1. 図１の横断面図である。It is a cross-sectional view of FIG. 図３の要部を拡大して示した図である。It is the figure which expanded and showed the principal part of FIG. 本発明に係る液晶表示装置の第２の実施形態を示す縦断面図である。It is a longitudinal cross-sectional view which shows 2nd Embodiment of the liquid crystal display device which concerns on this invention. 従来例を示す縦断面図である。It is a longitudinal cross-sectional view which shows a prior art example.

Explanation of symbols

１ランプ
２バックライト反射板
３拡散板
４光学シート
５液晶パネル
６キャビネット
６１，６２孔
６３背面側壁
７１回路基板
７２インバータ基板
７３映像基板
７４音声基板
８１〜８３補助仕切り板
９１リブ DESCRIPTION OF SYMBOLS 1 Lamp 2 Backlight reflecting plate 3 Diffuser plate 4 Optical sheet 5 Liquid crystal panel 6 Cabinet 61,62 Hole 63 Back side wall 71 Circuit board 72 Inverter board 73 Video board 74 Audio board 81-83 Auxiliary partition board 91 Rib

Claims

A liquid crystal display device in which a liquid crystal panel irradiated with a direct backlight is stored in the front part of the cabinet, a circuit board is disposed on the back surface of the reflector of the direct backlight, and ventilation means are formed on the lower and upper surfaces of the rear part of the cabinet. In
2. A liquid crystal display device according to claim 1, wherein the circuit board is disposed on the back surface of the reflecting plate substantially in parallel with the reflecting plate, and a natural convection is generated between the reflecting plate and the circuit board.

The liquid crystal display device according to claim 1.
A liquid crystal display device characterized in that a natural convection is generated between the circuit board and a back side wall of the cabinet.

The liquid crystal display device according to claim 1 or 2,
When the vertical dimension of the circuit board is less than the height of the back surface of the reflector, the circuit board is disposed on the lower side, and an auxiliary partition plate is provided on the circuit board at a portion that does not satisfy the height dimension above the circuit board. A liquid crystal display device characterized by being provided continuously.

The liquid crystal display device according to claim 3.
When there are a plurality of the circuit boards, the circuit board is arranged on the lower side only for the circuit board whose vertical dimension is less than the height of the back surface of the reflector, and the auxiliary partition plate is placed on the part that is less than the height dimension above the circuit board. A liquid crystal display device provided continuously with a substrate.

The liquid crystal display device according to claim 1,
The liquid crystal display device, wherein each circuit board and each auxiliary partition plate are attached to the back surface of the reflecting plate via vertical ribs.

The liquid crystal display device according to claim 4 or 5,
The liquid crystal display device according to claim 1, wherein the circuit boards are arranged so that the respective calorific values of the circuit boards are symmetrical or close to each other.

The liquid crystal display device according to claim 4 or 5,
The liquid crystal display device according to claim 1, wherein the circuit boards are arranged so that the values of the calorific values of the circuit boards are equal to the left and right or close to each other.

The liquid crystal display device according to any one of claims 4 to 7,
When there are two lighting circuit inverter boards as the circuit board, they are arranged at both left and right ends.