JP3584705B2 - Surface lighting device and display device - Google Patents

Description

【００１３】
以上示したように、Ｏリングの端部からの距離を冷陰極管直径の５倍以上とすることは、冷陰極管の寿命を満足する上で格別の効果を有する。
【００１４】
如何なる理由でこのような違いが発生するか明確にすることは困難であるが、実験中に観察した状況からから考察すると、
Ｏリング近傍の冷陰極管管面温度が低下していることから、Ｏリングは放熱部材としても機能していると考えられる。このため、冷陰極管中の水銀蒸気がＯリング近傍で液化・付着して水銀蒸気不足状態となる。Ｏリングが冷陰極管端部すなわち電極近傍に位置すると、電極部で水銀蒸気不足状態となり、電極金属物質のスパッタリングが加速され、更にスパッタリング被膜に水銀蒸気がアマルガムとして吸収されるという悪循環を起こし点灯異常に至ると推察している。従って、電極近傍で水銀蒸気が欠乏しないようにＯリングを遠ざけると寿命低下が回避される訳で、冷陰極管端部からの距離が管直径の５倍の位置に限界値が存在すると考えられる。
【００１５】
（実施例２）
図５、図６は、本発明の実施例２に係わる照明装置の光源を示す図。図７は、従来技術でＯリングを配置する例を示す。いずれも面照明装置をより高輝度化するため、Ｌ字型の冷陰極管を用いた例で、冷陰極管直径は３ｍｍである。Ｌ字型の冷陰極管を覆う反射部材は、２体或いはＬ字型形状のものとなるが断面形状は実施例１と同様である。図５の実施例では、実施例１と同様に弾性部材としてゴムを用いたＯリング６を冷陰極管１のそれぞれの辺の略中央部に冷陰極管１の外周部に沿って配置した。また、図６の実施例では、冷陰極管１の曲げ部に弾性部材としてゴムを用いたＯリング６を冷陰極管１の外周部に沿って配置した。図７は従来技術の例としてＯリングを冷陰極管端部から１２ｍｍの位置及び曲げ部に配置した。これらを実施例１と同様に面照明装置として組立、連続点灯試験したところ、図７に示す実施例で早期に点灯異常が発生したのに対し、本発明の意図するところである図５、図６の実施例では問題が無かった。
【００１６】
（実施例３）
図８は、本発明の実施例３に係わる照明装置の光源を示す図。図９は、従来技術でＯリングを配置する例を示す図。いずれも面照明装置を更に高輝度化するため、コの字型の冷陰極管を用いた例で、冷陰極管直径は４ｍｍとした。断面形状は実施例１と同様である。コの字型の冷陰極管を覆う反射部材は、３体或いはコの字型等、冷陰極管有効発光部を覆えば自由である。図８においては、弾性部材としてゴムを用いたＯリング６を本発明の意図するところに従い、冷陰極管端部から４０ｍｍの位置と冷陰極管１の曲げ部近傍とに冷陰極管１の外周部に沿って配置した。図９はＯリング６を冷陰極管１の端部から１８ｍｍの位置と冷陰極管１の曲げ部とに配置した。これらについても実施例１と同様に面照明装置として組立、連続点灯試験を行なった結果、図９に示した実施例のみ早期の点灯異常が発生した。
【００１７】
（実施例４）
図１０は、本発明の実施例４に係わる照明装置を示す図。図１１は図１０に示す実施例の断面図。導光板２に設けられた溝形状２１に冷陰極管１を埋め込んだもので、前記冷陰極管１に弾性部材としてゴムを用いたＯリング６を冷陰極管１の外周部に沿って配置した。前記Ｏリングは前記溝形状２１側面との衝突を防ぐ役割を果たす。この例においても、Ｏリングを冷陰極管１の端面から冷陰極管管径の５倍以内に配置すると、冷陰極管の寿命の減少を引き起こすため、Ｏリングの端面からの距離を冷陰極管管径の５倍以上離して配置した。
【００１８】
（実施例５）
図１２は、本発明の実施例５に係わる照明装置を示す断面図。以下図１２にもとづき説明する。冷陰極管１は前記実施例１に述べた直型で、冷陰極管１の外周部に沿って配置され、弾性部材としてゴムを用いたＯリング６は、冷陰極管端面から管径の５倍以上離れた領域に配置されており、例えば図２に示す冷陰極管を使用する。透過型液晶パネル７は面照明装置の上方に位置し、フレーム９により固定される。
（実施例６）図１３は、本発明の実施例６に係わる照明装置を示す断面図。基本構造は先に述べた実施例５と同様である。半透過型液晶パネル８を面照明装置の上方に配置したもので、前記半透過型液晶パネル８と面照明装置との間に半透過部材１０を有する。明所での使用時は半透過部材１０の反射性を利用して外部光を利用した反射モードで使用する。このような半透過部材１０の例としては、特表平９−５０６９８５号公報にその詳細が開示されている反射偏光子があげられる。また、暗所では面照明装置を点灯して透過モードで使用する。
【００１９】
実施例４、５は、いずれにしても、液晶パネルの背面照明を面照明装置で行なう時に、面照明装置に組み込まれる冷陰極管のＯリングを冷陰極管端部から管径の５倍以上離して配置することが特徴であり、その他部分の構造の違いに関係しない。また、実施例１〜３で直型・Ｌ字型・コの字型の、実施例４ではＵ字型の冷陰極管について説明したが、その他異形状の冷陰極管であっても同様の効果を示すことは言うまでもない。
【００２０】
更に、いずれの実施例もＯリングを用いて説明してきたが、冷陰極管と周辺部材とに隙間を設けることが目的であり、材質的にはゴム以外に合成樹脂、発泡樹脂或いは繊維物質等であっても良く、形状的にはＯリング形状以外に断面Ｃ字型の棒状のもの、冷陰極管表面に千鳥状に上記物質を配置したもの、繊維状の物質を冷陰極管にスパイラル状に巻き付けたもの或いは上記物質を粘着等した反射部材を冷陰極管に巻き付けたもの等であっても良く、同様の効果が得られる。
【００２１】
【発明の効果】
以上述べたように、本発明の面照明装置によれば、少なくとも、光源として蛍光管と、入射端面が前記光源の近傍に位置するように配置された導光板と、前記光源を覆う反射部材とで構成される面照明装置において、前記光源と反射部材とに間隙を設けるように、前記光源外周部に沿って弾性部材を設けたもので、前記弾性部材の配置される部位が、前記光源の端部から光源直径の５倍の距離以上離れていることを特長としたので、面照明装置の蛍光管の高周波電流のリークを無すことで低消費電力化を可能とし、携帯機器においては電池寿命を伸ばせるものである。また、蛍光管の破損を防止するとともに、寿命を減少させないという効果を有する。
【００２２】
また、導光板に溝形状を有し、前記溝形状に蛍光管を埋め込んでなる面照明装置において、前記光源と前記導光板溝面とに間隙を設けるように、前記光源外周部に沿って弾性部材を設けたもので、前記弾性部材の配置される部位が、前記光源の端部から光源直径の５倍の距離以内に無いことを特徴としたので、面照明装置の蛍光管の破損を防止するとともに、寿命を減少しないという効果を有する。
【００２３】
また、以上述べた効果を有する面照明装置を透過型液晶パネル或いは半透過型液晶パネルと組み合わせることにより同様の効果を有する表示装置を提供することが可能となった。
【図面の簡単な説明】
【図１】本発明の実施例１に係わる照明装置の構造を示す断面図。
【図２】上記照明装置の光源を示す図。
【図３】従来の照明装置の構造を示す断面図。
【図４】別の従来の照明装置の構造を示す断面図。
【図５】本発明の実施例２に係る照明装置の光源を示す図。
【図６】上記照明装置の別の光源を示す図。
【図７】上記照明装置の従来技術による光源を示す図。
【図８】本発明の実施例３に係る照明装置の光源を示す図。
【図９】上記照明装置の従来技術による光源を示す図。
【図１０】本発明の実施例２に係わる照明装置を示す図。
【図１１】上記照明装置の断面図。
【図１２】本発明の実施例５に係わる表示装置の断面図。
【図１３】本発明の実施例６に係わる表示装置の断面図。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a surface lighting device used as a backlight or the like of a liquid crystal display device, and relates to a surface lighting device using a light guide plate and a display device.
[0002]
[Prior art]
A conventional surface illumination device using a light guide plate includes a linear light source 1, a light guide plate 2 having an incident end face in proximity thereto, and a reflecting member 3 covering the light source 1, as shown in FIG. The linear light source uses a cold-cathode tube, and the light incident from the incident end face of the acrylic resin light guide plate 2 undergoes total reflection repeatedly on the upper and lower surfaces of the light guide plate 2 and is provided on the lower surface of the light guide plate 2 and the like. The light is extracted from the diffused portion as illumination light. The reflection member is required to have a high reflectance so that the light from the light source 1 is incident on the light guide plate 2 as much as possible, and a film on which aluminum or silver is deposited is often used.
[0003]
Another conventional example is shown in FIG. 4 of Utility Model Registration No. 2534634. In this configuration, O-rings are provided at both ends and the center of the cold cathode tube 1 in order to arrange the cold cathode tube 1 and the reflecting member 3 so as to form a gap. It is stated that the effect can be reduced.
[0004]
[Problems to be solved by the invention]
In the prior art described above, in the structure shown in FIG. 3, as pointed out in Utility Model Registration No. 2534634, the cold cathode tube 1 and the reflecting member 3 come into contact or come close to each other due to assembly variation. Leakage of high-frequency current, that is, reduction in luminance of the surface illumination device, may occur.
[0005]
On the other hand, the structure of Utility Model Registration No. 2534634 was effective as a countermeasure against leakage of high-frequency current, but a new problem occurred in that the cold cathode fluorescent lamp 1 caused abnormal lighting. In particular, this phenomenon occurred remarkably in a low-temperature operation state, and the life was remarkably earlier than that in the case where no O-ring was provided.
[0006]
[Means for Solving the Problems]
The surface illumination device of the present invention includes a cold cathode tube, a light guide plate having an incident end face on which light from the cold cathode tube enters near the cold cathode tube, and a reflecting member that covers the cold cathode tube. In the surface illumination device configured as described above, a plurality of elastic members are provided on an outer peripheral portion of the cold cathode tube so as to provide a gap between the cold cathode tube and the reflecting member, and the first elastic member is disposed. The portion is separated from one end of the cold cathode tube by a distance of at least five times the diameter of the cold cathode tube, and the portion where the second elastic member is disposed is located at the other end of the cold cathode tube from the other end. It is characterized in that the cold cathode tubes are separated by a distance of at least five times the diameter of the cold cathode tubes.
The surface illumination device of the present invention covers a linear light source, a linear light source, a light guide plate having an incident end face on which light from the linear light source enters near the linear light source, and covers the linear light source. In a surface lighting device including a reflecting member, an elastic member is provided on an outer peripheral portion of the linear light source so as to provide a gap between the linear light source and the reflecting member, and the elastic member is disposed. It is preferable that the portion is separated from the end of the linear light source by a distance equal to or more than five times the diameter of the light source.
[0007]
In addition, in order to protect the fluorescent tube from external force such as vibration and shock, to prevent abnormal lighting of the fluorescent tube, and to satisfy the life, the surface lighting device of the present invention is provided with a cold cathode tube in a groove formed in the light guide plate. In the embedded surface lighting device, a plurality of elastic members are provided on an outer peripheral portion of the cold cathode tube so as to provide a gap between the cold cathode tube and a groove surface of the light guide plate, and the first elastic member is disposed. Is located at least five times the diameter of the cold-cathode tube from one end of the cold-cathode tube, and the second elastic member is located at the other end of the cold-cathode tube. A distance of at least 5 times the diameter of the cold cathode tube.
The surface illumination device of the present invention is the surface illumination device in which a linear light source is embedded in a groove formed in the light guide plate, wherein the linear light source is provided so as to provide a gap between the linear light source and the groove surface of the light guide plate. It is preferable that an elastic member is provided on an outer peripheral portion, and that a portion where the elastic member is disposed is separated from an end of the linear light source by a distance equal to or more than five times a light source diameter.
[0008]
Further, a display device of the present invention is characterized by combining the above-mentioned surface lighting device with a transmissive liquid crystal panel or a transflective liquid crystal panel.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
[0010]
(Example 1)
FIG. 1 is a sectional view of a lighting device according to a first embodiment of the present invention, and FIG. 2 shows a cold cathode tube used in the first embodiment. This illumination device is composed of a cold cathode tube 1, a light guide plate 2, a reflection member 3, a reflection sheet 4, and a diffusion sheet 5, and their functions are the same as those of the conventional example shown in FIG. As shown in FIG. 2, an O-ring 6 using rubber as an elastic member is provided along the outer periphery of the cold cathode tube 1 in the cold cathode tube 1. As described in Utility Model Registration No. 2534634, this O-ring is for arranging the cold-cathode tube 1 and the reflecting member 3 with a gap, and has the same effect.
[0011]
In this embodiment, the diameter of the cold cathode tube 1 is 3 mm. As intended by the present invention, the O-ring 61 close to the end of the cold-cathode tube 1 was arranged at a position 20 mm from the end of the cold-cathode tube 1 (hereinafter referred to as a distance from the end of the O-ring). On the other hand, as an example of the prior art, cold-cathode tubes having a distance of 10 mm from the end of the O-ring were also prepared, and 20 surface illumination devices using the respective cold-cathode tubes were assembled and tested. The test conditions were such that a very common surface illumination device that was left in an environment of 0 ° C. was continuously lit with a cold-cathode tube current of 5 mA. Table 1 below shows the time required for the CCFL to reach lighting abnormalities.
[0012]
[Table 1]

[0013]
As described above, setting the distance from the end of the O-ring to five times or more the diameter of the cold-cathode tube has a remarkable effect in satisfying the life of the cold-cathode tube.
[0014]
It is difficult to clarify why such a difference occurs, but from the situation observed during the experiment,
Since the cold-cathode tube surface temperature near the O-ring has dropped, it is considered that the O-ring also functions as a heat radiating member. For this reason, the mercury vapor in the cold cathode tube liquefies and adheres near the O-ring, and a mercury vapor shortage state occurs. When the O-ring is located near the end of the cold cathode tube, that is, in the vicinity of the electrode, a shortage of mercury vapor occurs at the electrode portion, the sputtering of the electrode metal material is accelerated, and the sputtered film causes a vicious cycle in which the mercury vapor is absorbed as amalgam. It is speculated that this will lead to abnormalities. Therefore, if the O-ring is kept away from the vicinity of the electrode so that the mercury vapor is not depleted, the life is shortened. Therefore, it is considered that the limit value exists at a position where the distance from the end of the cold cathode tube is five times the tube diameter. .
[0015]
(Example 2)
5 and 6 are views showing a light source of a lighting device according to a second embodiment of the present invention. FIG. 7 shows an example in which an O-ring is arranged in the related art. Each of the examples uses an L-shaped cold cathode tube in order to further increase the brightness of the surface illumination device, and the diameter of the cold cathode tube is 3 mm. The reflecting member that covers the L-shaped cold-cathode tube has two or L-shaped shapes, but the cross-sectional shape is the same as that of the first embodiment. In the embodiment shown in FIG. 5, an O-ring 6 using rubber as an elastic member is disposed substantially at the center of each side of the cold cathode tube 1 along the outer peripheral portion of the cold cathode tube 1 as in the first embodiment. In the embodiment of FIG. 6, an O-ring 6 using rubber as an elastic member is arranged along the outer periphery of the cold cathode tube 1 at the bent portion of the cold cathode tube 1. FIG. 7 shows an example of the prior art in which an O-ring is disposed at a position 12 mm from the end of the cold cathode tube and at a bent portion. These were assembled as a surface illuminating device in the same manner as in Example 1 and subjected to a continuous lighting test. As a result, although the lighting abnormality occurred early in the embodiment shown in FIG. 7, FIGS. 5 and 6 intended by the present invention. There was no problem in the example of (1).
[0016]
(Example 3)
FIG. 8 is a diagram illustrating a light source of a lighting device according to a third embodiment of the present invention. FIG. 9 is a diagram showing an example in which an O-ring is arranged in the related art. In each case, in order to further increase the brightness of the surface illumination device, a U-shaped cold cathode tube was used, and the diameter of the cold cathode tube was 4 mm. The cross-sectional shape is the same as in the first embodiment. The reflecting member that covers the U-shaped cold cathode tube is free as long as it covers the cold-cathode tube effective light emitting portion, such as a three-body or U-shaped reflecting member. In FIG. 8, an O-ring 6 using rubber as an elastic member is provided at the position 40 mm from the end of the cold cathode tube and near the bent portion of the cold cathode tube 1 according to the intention of the present invention. It was arranged along the part. In FIG. 9, the O-ring 6 is arranged at a position 18 mm from the end of the cold cathode tube 1 and at a bent portion of the cold cathode tube 1. As for these, as in the case of Example 1, assembling as a surface lighting device and a continuous lighting test were performed. As a result, early lighting abnormalities occurred only in the example shown in FIG.
[0017]
(Example 4)
FIG. 10 is a diagram illustrating a lighting device according to a fourth embodiment of the present invention. FIG. 11 is a sectional view of the embodiment shown in FIG. The cold cathode tube 1 is embedded in a groove shape 21 provided in the light guide plate 2, and an O-ring 6 using rubber as an elastic member is arranged along the outer periphery of the cold cathode tube 1 in the cold cathode tube 1. . The O-ring serves to prevent collision with the side surface of the groove 21. Also in this example, if the O-ring is arranged within 5 times the diameter of the cold-cathode tube from the end face of the cold-cathode tube 1, the life of the cold-cathode tube is reduced. They were arranged at a distance of at least 5 times the pipe diameter.
[0018]
(Example 5)
FIG. 12 is a sectional view showing a lighting device according to a fifth embodiment of the present invention. This will be described below with reference to FIG. The cold-cathode tube 1 is the straight type described in the first embodiment, and is arranged along the outer peripheral portion of the cold-cathode tube 1. An O-ring 6 using rubber as an elastic member has a diameter of 5 mm from the cold-cathode tube end face. It is arranged in a region more than twice as far away, and uses, for example, a cold cathode tube shown in FIG. The transmissive liquid crystal panel 7 is located above the surface lighting device and is fixed by the frame 9.
(Embodiment 6) FIG. 13 is a sectional view showing a lighting device according to Embodiment 6 of the present invention. The basic structure is the same as that of the fifth embodiment. The transflective liquid crystal panel 8 is disposed above the surface lighting device, and has a transflective member 10 between the transflective liquid crystal panel 8 and the surface lighting device. When used in a light place, the light is used in a reflection mode using external light by utilizing the reflectivity of the transflective member 10. An example of such a semi-transmissive member 10 is a reflective polarizer whose details are disclosed in Japanese Patent Publication No. 9-506985. In a dark place, the surface illumination device is turned on and used in the transmission mode.
[0019]
In any of the fourth and fifth embodiments, when the backlight of the liquid crystal panel is illuminated by the surface illumination device, the O-ring of the cold cathode tube incorporated in the surface illumination device is at least five times the tube diameter from the end of the cold cathode tube. The feature is that they are arranged apart from each other, and are not related to the difference in the structure of other parts. Further, although the direct-type, L-shaped, and U-shaped cold-cathode tubes have been described in the first to third embodiments, and the U-shaped cold-cathode tube has been described in the fourth embodiment, the same applies to other cold-cathode tubes of other shapes. Needless to say, it is effective.
[0020]
Furthermore, although all the embodiments have been described using the O-ring, the purpose is to provide a gap between the cold-cathode tube and the peripheral members. In addition to the O-ring shape, a C-shaped cross-section rod, a staggered arrangement of the above substances on the surface of a cold cathode tube, or a fibrous substance in a spiral shape in a cold cathode tube may be used. Or a reflection member having the above substance adhered to a cold cathode tube, and the same effect can be obtained.
[0021]
【The invention's effect】
As described above, according to the surface illumination device of the present invention, at least, a fluorescent tube as a light source, a light guide plate disposed so that an incident end face is located near the light source, and a reflecting member that covers the light source. In the surface illumination device configured by the above, an elastic member is provided along the outer periphery of the light source so as to provide a gap between the light source and the reflecting member, and a portion where the elastic member is disposed, Its feature is that it is more than 5 times the diameter of the light source from the end, so it can reduce power consumption by eliminating the leakage of high-frequency current from the fluorescent tube of the surface illumination device. It can extend the life. In addition, there is an effect that the breakage of the fluorescent tube is prevented and the life is not shortened.
[0022]
Further, in a surface illumination device having a light guide plate having a groove shape and a fluorescent tube embedded in the groove shape, elasticity is provided along the light source outer peripheral portion so as to provide a gap between the light source and the light guide plate groove surface. A member is provided, and the portion where the elastic member is disposed is not within a distance of 5 times the light source diameter from the end of the light source, so that the fluorescent tube of the surface lighting device is prevented from being damaged. And has the effect of not reducing the life.
[0023]
Further, by combining the surface lighting device having the above-described effects with a transmissive liquid crystal panel or a transflective liquid crystal panel, a display device having the same effect can be provided.
[Brief description of the drawings]
FIG. 1 is a sectional view showing the structure of a lighting device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a light source of the lighting device.
FIG. 3 is a cross-sectional view illustrating a structure of a conventional lighting device.
FIG. 4 is a cross-sectional view showing the structure of another conventional lighting device.
FIG. 5 is a diagram showing a light source of a lighting device according to a second embodiment of the present invention.
FIG. 6 is a view showing another light source of the lighting device.
FIG. 7 is a diagram showing a light source according to the prior art of the lighting device.
FIG. 8 is a diagram showing a light source of a lighting device according to a third embodiment of the present invention.
FIG. 9 is a diagram showing a light source according to the prior art of the lighting device.
FIG. 10 is a diagram showing a lighting device according to a second embodiment of the present invention.
FIG. 11 is a cross-sectional view of the lighting device.
FIG. 12 is a sectional view of a display device according to a fifth embodiment of the present invention.
FIG. 13 is a sectional view of a display device according to a sixth embodiment of the present invention.

Claims (3)

A cold cathode tube, the cold-cathode tube entrance end face and a light guide plate disposed in the vicinity of the cold cathode tube enters the light, covers the cold cathode tube reflecting member and configured surface illumination device has a At
A plurality of elastic members are provided on the outer periphery of the cold cathode tube so as to provide a gap between the cold cathode tube and the reflecting member, and a portion where the first elastic member is disposed is provided at one end of the cold cathode tube. Part of the cold-cathode tube is at least five times the diameter of the cold-cathode tube, and the portion where the second elastic member is disposed is five times the diameter of the cold-cathode tube from the other end of the cold-cathode tube. An area lighting device which is separated by a distance or more . In a surface lighting device in which a cold cathode tube is embedded in a groove formed in a light guide plate, a plurality of elastic members are provided on an outer peripheral portion of the cold cathode tube so as to provide a gap between the cold cathode tube and a groove surface of the light guide plate. provided with, and spaced first of said elastic portion is disposed in the member at least five times the distance of the diameter of the cold cathode tubes from one end of the cold cathode tube is disposed in the second of said resilient member A surface of the cold-cathode tube is separated from the other end of the cold-cathode tube by a distance at least five times the diameter of the cold-cathode tube . A display device comprising a transmissive liquid crystal panel or a transflective liquid crystal panel and the surface illumination device according to claim 1 or 2 combined.

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