JP2008077921A - Backlight device and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem, wherein electrode reception fittings incur much manufacturing cost and the size of the case for housing them therein must be increased, in a backlight device. <P>SOLUTION: This backlight device is provided with a plurality of fluorescent lamps 20 each having a shape including a U-shaped or W-shaped form, each having external electrodes on outside surfaces arranged at both ends, and arranging the electrodes on the same side; the electrode reception fitting 3a, having a U-shaped or comb-like form and connecting the one-side electrodes 2a of the plurality of fluorescent lamps 20 with each other; and the electrode reception fitting 3b, having a U-shaped or comb-like form and connecting the other-side electrodes 2b with each other; and a single step-up circuit 10 that makes the plurality of fluorescent lamps 20 light up; and is characterized by arranging the one side of the electrode reception fitting 3a and the electrode reception fitting 3b without straddling the other side. According to this structure, standardization is obtained by arranging the electrode reception fittings having the same shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a backlight device and a display device having a fluorescent lamp in which external electrodes are arranged on the outer surfaces of both ends.

  Generally, a light source used in a backlight device of a display device such as a liquid crystal display device is mainly a cold cathode type lamp (internal electrode type lamp) having an electrode inside a glass tube. However, in recent years, backlight devices using a discharge type lamp (external electrode type lamp or EEFL) having an electrode outside the glass tube have been seen. As a reason for this, the number of lamps used in the backlight device has been increasing in recent years in the enlargement and area increase of liquid crystals and the like. When a backlight device using a plurality of lamps is realized, the conventional internal electrode type lamp requires a booster circuit for each lamp. On the other hand, the external electrode type lamp can be lit with a single booster circuit, which makes the lighting circuit and wiring structure simple.

  A lamp used in a display device such as a liquid crystal display device has a fluorescent film formed on the inner surface of a lamp tube. Due to the problem in the manufacturing method of applying the phosphor to the inner surface of the lamp tube, the thickness of the phosphor film becomes non-uniform, thereby causing the problem of non-uniform luminance.

  As a method for solving this, there are techniques such as Patent Document 1 and Patent Document 2. According to these patent documents, when forming the phosphor coating on the inner surface of the fluorescent lamp tube, the film thickness of the phosphor coating differs between the exhaust side for exhausting the inside of the lamp tube to a vacuum state and the sealed side. Occurs. As a result, luminance and chromaticity non-uniformity occurs, and as a means for solving the problem, non-uniformity in luminance and chromaticity is improved by alternately arranging the exhaust side and the sealing side of the fluorescent tube.

  Patent Document 2 shows a case of a backlight device using a lamp in which an external electrode lamp is bent. A schematic diagram thereof is shown in FIG. In FIG. 5, each fluorescent lamp is connected in series and is lit by one booster circuit. However, in recent years, backlight devices used in liquid crystal devices and the like have become larger in liquid crystal, and in the case where the lighting circuit is configured in series connection as shown in FIG. In order to light the lamp, the voltage applied to the lamp needs to be higher. However, due to the characteristics of the lamp, ozone is generated when the voltage is high, and it is not realistic from the viewpoint of safety. There is a problem.

As a method for solving this, a backlight device having the configuration shown in FIG. 6 is generally used. In FIG. 6, the fluorescent lamps are connected in parallel and are lit by one booster circuit. The backlight device shown in FIG. 6 will be described. A plurality of fluorescent lamps 20 having external electrodes are arranged, and the fluorescent lamp 20 is bent and the electrodes 2a and 2b are arranged on the same side. The electrode 2a side of the plurality of lamps is fixed by an electrode bracket 3a, and the electrode 2b side is fixed by an electrode bracket 3b. The electrodes 3a and 3b are connected to the booster circuit 10 so that a plurality of lamps can be lit in parallel. Here, the lamp electrodes 2a and 2b do not indicate the exhaust side and the sealing side of the fluorescent tube, but the electrode fixed by the electrode bracket 3a is 2a and the opposite side is 3b. Further, as described in Patent Document 1 and Patent Document 2, it is assumed that the sealing side and the exhaust side of the fluorescent tube are alternately arranged. In this way, the fluorescent tube is bent into a U-shape, and the sealing side and the exhaust side are reversed to cancel out the non-uniformity of the phosphor coating.
JP 2003-36723 A JP 2003-36703 A

  However, in the configuration of the electrode portion of the backlight device shown in FIG. 6, in order to connect the electrode receiving brackets 3a and 3b to the booster circuit, the electrode receiving bracket 3a and the electrode receiving bracket 3b must be crossed due to the structure. In order to prevent the electrode receiving metal fitting 3a and the electrode receiving metal fitting 3b from coming into contact with each other, the electrode receiving metal fitting must be shaped so that one of the electrode receiving metal fittings straddles the other. Thus, in manufacturing the electrode receiving metal fitting 3a and the electrode receiving metal fitting 3b, different molds must be manufactured and the electrode receiving metal fittings must be manufactured. In addition, since the electrodes are disposed in the portion where the lamp does not exist due to the structure, the case 40 must be made larger by that amount. In addition, there is a problem in that the leakage current between the electrode brackets increases at the portion where the electrode brackets straddle, resulting in loss of power efficiency.

  In order to solve this problem, the backlight device of the present invention has a plurality of external electrodes disposed on the outer surfaces of both ends, a shape including a U shape or a W shape, and electrodes disposed on the same side. A fluorescent lamp and a shape including a U-shaped or comb-shaped shape, an electrode bracket A for electrically connecting one electrode of the plurality of fluorescent lamps, and a shape including a U-shaped or comb-shaped shape; An electrode receiving bracket B for connecting electrodes and a single booster circuit for lighting the plurality of fluorescent lamps, wherein one of the electrode receiving bracket A and the electrode receiving bracket B is disposed without straddling the other. And

  Further, the backlight device of the present invention has a plurality of fluorescent lamps in which external electrodes are arranged on the outer surfaces of both end portions, have a shape including a U shape or a W shape, and electrodes are arranged on the same side, An electrode holder A for electrically connecting one electrode of the plurality of fluorescent lamps; an electrode holder B for connecting the other electrode; and a single booster circuit for lighting the plurality of fluorescent lamps. The electrode positions are arranged at asymmetric positions, and one of the electrode bracket A and the electrode bracket B is disposed without straddling the other.

  If the backlight device according to the present invention is used, it is possible to share the electrode receiving bracket by making the shape of the electrode receiving bracket the same, and the electrode receiving bracket can be arranged without crossing. It is possible to prevent the leakage current at the part and improve the efficiency.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
Embodiment 1 of the present invention will be described with reference to FIG.

  In the backlight device 100 shown in FIG. 1, external electrodes are arranged on the outer surfaces of both ends, a plurality of fluorescent lamps 20 having a U-shape and electrodes arranged on the same side are arranged. The electrode 2a on one side of the fluorescent lamp 20 is fixed with an electrode bracket 3a, and the other electrode 2b is fixed with an electrode bracket 3b. The electrode bracket 3a and the electrode bracket 3b are connected to the booster circuit 10, and a plurality of fluorescent lamps can be lit in parallel. The plurality of fluorescent lamps 20, the electrode bracket 3 a, and the electrode bracket 3 b are housed in a case 40. The inner surface of the case 40 is devised so that light can be efficiently emitted from the opening surface by a reflection sheet or the like.

  Hereinafter, a detailed description will be given in comparison with the prior art. First, the shape of the electrode bracket in the conventional embodiment is shown in FIG. In the conventional example, in order to realize a circuit configuration for boosting a plurality of fluorescent lamps having external electrodes on the same side in parallel, either the electrode receiving bracket 3a or the electrode receiving bracket 3b must be disposed across one of them. I must. In FIG. 7, the electrode bracket 3b is arranged so as to straddle the electrode bracket 3a. Thus, it is necessary to form such a shape that one of the two straddles the other, and it is necessary to prepare two types of metal molds for the electrode receiving bracket when manufacturing. This causes a loss in terms of cost. In addition, since the electrode brackets must be straddled, a new overlapping part of the electrode brackets is generated compared to the case where the electrode brackets are not straddled, and a new leakage current is generated between the partial electrode brackets. There is a problem of loss.

  FIG. 2 shows the electrode receiving metal fitting 3a and the electrode receiving metal fitting 3b in the present invention, but the electrode receiving metal fittings have the same shape, and those having a comb shape are arranged in the opposite direction. In the invention of the first embodiment, the shape of the electrode bracket is not limited to the same, but here, a case where the same shape is used will be described from the viewpoint that the electrode bracket can be shared. As a result, it is possible to boost a plurality of fluorescent lamps having external electrodes on the same side in parallel without straddling the electrode bracket. Therefore, it is possible to use the electrode receiving metal fitting 3a and the electrode receiving metal fitting 3b having the same shape, and the structure can be simplified and the cost can be reduced. Further, since the portion of the electrode bracket 3a and the electrode bracket 3b straddling can be eliminated, the leakage current between the electrode brackets can be reduced, and the efficiency can be improved. Here, the plurality of fluorescent lamps 20 are U-shaped, but the present invention is not limited to this, and any external electrode type fluorescent lamp having electrodes on the same side may be used.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIG.

  In the backlight device 200 shown in FIG. 3, a plurality of fluorescent lamps 20 are arranged in which external electrodes are arranged on the outer surfaces of both end portions, and the shape is U-shaped and electrodes are arranged on the same side. Twenty external electrodes 2a and 2b are arranged at asymmetric positions. The electrodes 2a on one side of the plurality of fluorescent lamps 20 are fixed by an electrode bracket 3a, and the other electrode 2b is fixed by an electrode bracket 3b. The electrode bracket 3a and the electrode bracket 3b are connected to the booster circuit 10 and can light a plurality of fluorescent lamps in parallel. The plurality of fluorescent lamps 20, the electrode bracket 3 a, and the electrode bracket 3 b are housed in a case 40. The inner surface of the case 40 is devised so that light can be efficiently emitted from the opening surface by a reflection sheet or the like.

  Detailed description will be given below. The fluorescent lamp 20 shown in FIG. 3 is formed by shifting the positions of the external electrode 2a and the external electrode 2b so that the electrodes are arranged at asymmetric positions. Then, the electrode 2a side of the plurality of fluorescent lamps is fixed with the electrode bracket 3a, and the other electrode 2b side is fixed with the electrode bracket 3b. At this time, since the electrode positions of the fluorescent lamps 20 are asymmetrical positions, the electrode brackets 3a and 3b can be linear (rectangular). Therefore, it is possible to use the electrode receiving metal fitting 3a and the electrode receiving metal fitting 3b having the same shape, and the structure can be simplified. This makes it possible to reduce costs. Further, since it is not necessary to carry out wiring straddling the electrode bracket 3a and the electrode bracket 3b, it is possible to suppress the leakage current in the overlapping portion of the electrode bracket and to improve the efficiency. . Here, the plurality of fluorescent lamps 20 are U-shaped, but the present invention is not limited to this, and any external electrode type fluorescent lamp having electrodes on the same side may be used.

(Embodiment 3)
Embodiment 3 of the present invention will be described with reference to FIG.

  The embodiment of the present invention is the same as that described in the first and second embodiments, and only the difference will be described. A feature of the present invention is that the electrode bracket 3a and the electrode bracket 3b are covered with an insulator such as a reflection sheet. As shown in FIG. 4, an insulator such as a reflection sheet 50 is disposed on the electrode bracket. When the electrode bracket 3b of FIG. 4 is disposed above the reflection sheet, the light from the lamp incident on the electrode bracket 3b cannot be efficiently reflected. Therefore, by adopting a configuration in which the reflection sheet is placed on the electrode bracket, it is possible to efficiently reflect and use the light incident on the electrode portion. In addition, as a backlight device, the luminance unevenness of light at the electrode portion is eliminated and uniform light emission is possible. Further, by covering with an insulator, it is possible to suppress the leakage current between the lamp and the electrode, and it is possible to improve the efficiency. Here, a case where a reflective sheet is newly separately covered on the electrode bracket 3a and the electrode bracket 3b may be used. Further, an electrode holder may be disposed under the reflection sheet. In this case, it is assumed that the case and the electrode bracket are insulated.

  Note that by using the backlight device described in Embodiments 1 to 3 of the present invention for a display device, the luminance cross section of light emission can be uniform and uneven, or the luminance can be improved.

  By using the backlight device and the display device according to the present invention, it is possible to share the electrode bracket, and it is useful as a backlight device with improved power efficiency at low cost.

The figure which shows the structure of the backlight apparatus in Embodiment 1 of this invention The figure which shows the structure of the electrode periphery in Embodiment 1 of this invention The figure which shows the structure of the backlight apparatus in Embodiment 2 of this invention. The figure which shows the structure around the electrode in Embodiment 3 of this invention The figure which shows the structure of the conventional backlight apparatus The figure which shows the structure of the other conventional backlight apparatus The figure which shows the structure around the electrode of the conventional backlight apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Booster circuit 20 Fluorescent lamp 2a, 2b Electrode 3a, 3b Electrode metal fitting 40 Case 50 Reflective sheet

Claims (5)

A plurality of fluorescent lamps in which external electrodes are arranged on the outer surfaces of both ends, having a shape including a U shape or a W shape, and electrodes arranged on the same side;
An electrode bracket A having a shape including a U-shape or a comb-shape, and electrically connecting one electrode of the plurality of fluorescent lamps;
An electrode bracket B having a shape including a U-shape or a comb-shape and connecting the other electrode;
A single booster circuit for lighting the plurality of fluorescent lamps,
One of the electrode receiving metal fittings A and the electrode receiving metal fittings B is arranged without straddling the other. A plurality of fluorescent lamps in which external electrodes are arranged on the outer surfaces of both ends, having a shape including a U shape or a W shape, and electrodes arranged on the same side;
An electrode bracket A for electrically connecting one electrode of the plurality of fluorescent lamps;
An electrode bracket B for connecting the other electrode;
A single booster circuit for lighting the plurality of fluorescent lamps,
The backlight device is characterized in that the electrode position of the fluorescent lamp is disposed at an asymmetrical position, and one of the electrode bracket A and the electrode bracket B is disposed without straddling the other. The backlight device according to claim 1 or 2, wherein the upper electrode receiving bracket A and the electrode receiving bracket B have the same shape. 4. The backlight device according to claim 1, wherein the electrode receiving bracket A and the electrode receiving bracket B are covered with an insulating material. 5. A display device comprising the backlight device according to claim 1.