JP4117088B2 - Light source for backlight and backlight - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a backlight light source used for a display device such as a liquid crystal display, a signboard, and the like and a backlight including the same, and more particularly to an aspect of connection between a lamp tube and a flat cable.
[0002]
[Prior art]
A backlight for a liquid crystal display device such as a liquid crystal television or a portable personal computer is provided with a linear light source facing the end face of the light guide plate, and light emitted from the linear light source is liquid crystal via the light guide plate. Irradiate the display device. The linear light source includes, for example, a straight tubular fluorescent lamp tube (hereinafter referred to as a lamp tube) having a tube diameter of 2 mm and a length of 300 mm, and a cable for supplying electric power to the lamp tube. The cable is a round cable in which the periphery of the core wire is covered with an insulating material, and the electrodes provided at both ends of the lamp tube and the core wire of the round wire cable are electrically connected to supply current to the lamp tube. It has become.
[0003]
In recent years, the demand for liquid crystal display devices has increased, and the size of liquid crystal display screens has increased, and there has been a demand for narrower frames of devices. Accordingly, in order to reduce the space for storing the conductor cable, a flat cable is used instead of the round cable. FIG. 3 is a schematic cross-sectional view showing the structure of a conventional light source for a backlight. In the figure, reference numeral 1 denotes a spacer type lamp tube. Conductive portions 1a for energizing electrodes (not shown) are provided flat at both ends of the lamp tube 1. The flat cable 20 has a configuration in which the metal core wire 2 is covered with the covering bands 3 and 3 from both sides, and the lamp tube 1 is arranged on the flat cable 20 in the same length direction. The flat cable 20 is longer than the lamp tube 1, and at one end thereof, the lower covering band 3a is left, the upper covering band is peeled off to expose the core wire 2, and the covering band 3a and the exposed core 2a are The tube 1 is bent into an L shape. Solder 40 is filled between the conductive portion 1 a of the lamp tube 1 and the exposed core 2 a facing the conductive portion 1 a, and the lamp tube 1 and the flat cable 20 are electrically connected via the solder 40.
[0004]
[Problems to be solved by the invention]
In the lamp tube having the above-described configuration, the distance between the conductive portion 1a and the exposed core 2a is small, so that the solder easily adheres to the covering band 3a during the soldering operation. As a result, the covering band 3a is damaged, the covering band 3a is peeled off from the exposed core 2a, and the connection between the conductive portion 1a and the exposed core 2a is incomplete.
[0005]
When the lead type lamp tube is used, the above-mentioned problems are solved. FIG. 4 is a schematic sectional view showing the structure of a light source for backlight using a lead type lamp tube. As shown in FIG. 4, a lead rod 1 b serving as a conductive portion projects from the end of the lamp tube 1. The lead bar 1b has an L shape, and the tip thereof is fitted into a through hole of a flat cable 20 described later. The flat cable 20 has a configuration in which the metal core wire 2 is covered with the covering bands 3 and 3 from both sides, and the lamp tube 1 is arranged on the flat cable 20 in the same length direction. The flat cable 20 extends longer than the lamp tube 1, and the lower covering band 3 a is left in the extended portion, and the upper covering band is peeled off to expose the core wire 2. The exposed core 2a extends in the length direction. The exposed core 2a and the covering band 3a are provided with through holes for passing the lead rod 1b. The solder 40 covers the penetrating portion between the lead bar 1b and the exposed core 2a, and the lamp tube 1 and the flat cable 20 are electrically connected.
[0006]
When the lead type lamp tube 1 is used in this way, the distance between the extended portion of the flat cable 20 and the tip of the lamp tube 1 is wide, so that the operation of welding the solder 40 onto the exposed core 2a is easy. Thus, the covering band 3a is not damaged, and the electrical connection between the lamp tube 1 and the flat cable 20 is ensured. However, a separate step of passing the lead bar 1b through the through hole of the flat cable 20 is necessary. Further, since the tip of the lead bar 1b protrudes from the flat cable 20, the lamp tube 1 and the flat cable 20 become non-parallel and there is a problem that the storage space cannot be reduced.
[0007]
The present invention has been made in view of such circumstances, and the lamp tube and the flat cable can be easily connected without penetrating the conductive portion through the flat cable, thereby preventing the flat cable from being damaged or deformed. An object of the present invention is to provide a light source for a backlight that is securely connected electrically and a backlight including the light source.
[0008]
[Means for Solving the Problems]
A backlight light source according to a first aspect of the present invention includes a lamp tube placed on a flat cable whose core wire is covered from both sides by an insulating band, a conductive portion provided at the tip of the lamp tube, and a tip of the flat cable. In the backlight light source electrically connected to the core wire exposed in step (a), the flat cable extends in the length direction beyond the distal end portion of the lamp tube, and the insulation portion is provided at the extended portion. A connecting material is attached to cover the core wire exposed from the belt and the tip of the lamp tube.
[0009]
In the first invention, since the flat cable extends in the length direction of the lamp tube, the exposed core wire extends substantially parallel to the lamp tube. As a result, there is a sufficient space between the tip of the lamp tube and the exposed core wire, and it is easy to attach the connecting material so as to cover the tip of the lamp tube and the core wire, and the flat cable is damaged. Deformation is prevented. Further, since the connecting member is attached to cover the tip of the lamp tube provided with the conductive portion, the conductive portion and the core wire are electrically connected without allowing the conductive portion to penetrate the flat cable.
[0010]
The backlight light source according to a second aspect of the present invention is the light source for the backlight according to the first aspect, wherein the extended portion of the flat cable exposes the core wire leaving the insulating band far from the lamp tube, and the connecting material is The core portion of the extending portion is covered on the insulating band.
[0011]
In the second invention, since the core wire of the flat cable is very thin, in order to maintain the strength of the flat cable, the other side is peeled off except for one side covering band, and the core wire is exposed to the lamp tube side. By attaching the connecting material on the exposed core wire and insulating band of the extended portion, the core wire and the conductive portion of the lamp tube can be connected with an easy operation.
[0012]
The backlight light source according to the third invention is characterized in that, in the first or second invention, solder is welded as the connecting material.
[0013]
In the third invention, as described above, since there is a sufficient distance between the tip of the lamp tube and the exposed core wire, the solder can be welded to the target region, and the flat cable can be connected with the high-temperature solder. There is no damage.
[0014]
A backlight according to a fourth invention includes at least the light source according to any one of the first to third inventions, and a light guide plate disposed with its end face facing the light source.
[0015]
In the fourth aspect of the invention, a light source with reliable electrical connection between the lamp tube and the flat cable is used, so that a high-performance backlight is obtained.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
FIG. 1 is a perspective view showing a configuration of a main part of a backlight using a light source according to the present invention. In the figure, reference numeral 100 denotes a linear light source shown in the present embodiment, which is a straight tubular lamp tube 1, a flat cable 20 along the lower side thereof, and covers 8 and 9 covering both ends of the lamp tube 1, respectively. And cords 7 and 7 for supplying a current to the lamp tube 1. The lamp tube 1 is a spacer-type fluorescent lamp having a tube diameter of 2 mm and a length of 300 mm. A light guide plate 10 is arranged in such a manner that the end surface of the lamp tube 1 is opposed to the lamp tube 1 at a predetermined distance.
[0017]
A current is supplied to the lamp tube 1 from a power source (not shown) via the cord 7 and the flat cable 20, and light emitted from the lamp tube 1 is introduced into the light guide plate 10 from the end face. The light incident on the light guide plate 10 is reflected and scattered by the lower surface of the light guide plate 10, and is emitted from the upper surface while traveling through the light guide plate 10. Sheets (not shown) such as a diffusion plate, a prism sheet, and a polarizing plate are stacked above the light guide plate 10, and light emitted from the light guide plate 10 is repeatedly diffused and condensed by these sheets, A liquid crystal display device (not shown) disposed on the upper layer of the backlight is irradiated.
[0018]
FIG. 2 is an enlarged vertical sectional view of the region II shown in FIG. 1, and shows a connection state between the lamp tube of the linear light source and the flat cable. A tip portion 11 of the lamp tube 1 shown in FIG. 2 is provided with a flat conductive portion 1a that does not protrude from the tip portion 11. The conductive portion 1a is for energizing an electrode (not shown) of the lamp tube 1. The flat cable 20 has a structure in which the metal core wire 2 is covered with the covering bands 3 and 3 from both sides, and the lamp tube 1 is placed on the covering band 3 with the same length direction. The pipe 1 is arranged substantially in parallel. The distal end side of the flat cable 20 extends longer than the lamp tube 1. This extended portion leaves the lower covering band 3a, and the upper covering band is peeled off to expose the core wire 2. The covering band 3 a and the exposed core 2 a extend in the length direction of the lamp tube 1.
[0019]
As shown in FIG. 2, solder 4 is attached to the ends of the flat cable 20 and the lamp tube 1. The solder 4 covers from the covering band 3a of the extended portion of the flat cable 20 to the tip portion 11 of the lamp tube 1, whereby the exposed core 2a and the conductive portion 1a of the lamp tube 1 are electrically connected. Yes. Since there is a sufficient distance between the coating strip 3a and the exposed core 2a and the tip 11 of the lamp tube 1, the solder 4 can be easily welded.
[0020]
On the other hand, on the opposite side of the above-described tip portion of the linear light source 100, the cords 7 and 7 are directly connected to the conductive portion provided at the tip portion of the lamp tube 1 and the tip of the flat cable 20, respectively. 7 are connected to a power source (not shown) (see FIG. 1).
[0021]
In the linear light source 100 having the above-described configuration, the flat cable 20 extends in the length direction at the distal end portion 11 of the lamp tube 1, so that the distance between the distal end portion 11 of the lamp tube 1 and the exposed core 2 a is sufficient. Therefore, the work of connecting the tip 11 including the conductive portion 1a and the exposed core 2a with the solder 4 can be easily performed. As a result, the flat cable 20 is prevented from being damaged and deformed, and the current supply to the lamp tube 1 can be reliably performed.
[0022]
In this embodiment, the case where only one tip 11 of the lamp tube 1 is connected to the flat cable 20 with the solder 4 is described. However, the present invention is not limited to this, and both ends are similarly flat. It can also be applied to configurations that connect to cables. In this case, current is supplied from the center side of the flat cable 20.
[0023]
In the present embodiment, the case where a straight fluorescent lamp is used for the lamp tube 1 is described. However, the present invention is not limited to this, and the same effect can be obtained by using other discharge lamps. Further, the same effect can be obtained not only in the case of a straight tube but also in the case of using an M-shaped or U-shaped lamp tube.
[0024]
Further, in the present embodiment, the lamp tube 1 is described by taking a spacer type in which the flat conductive portion 1a is provided at the tip portion 11 as an example. However, the present invention is not limited to this, and the conductive portion protrudes. Applicable to shapes. In this case, the connecting member is attached without penetrating the tip of the conductive portion through the flat cable.
[0025]
Furthermore, in the present embodiment, the lamp tube 1 and the flat cable 20 are connected by welding the solder 4, but the present invention is not limited to this. For example, the conductive portion of the lamp tube may be melted by electron beam irradiation and fused to the core wire.
[0026]
Furthermore, in the present embodiment, the structure in which the extension portion of the flat cable 20 maintains the strength with the covering band 3a on one side is described. However, the present invention is not limited to this. A reinforcing material may be attached to the lower side of the core wire.
[0027]
【The invention's effect】
As described above, in the present invention, the flat cable is extended in the length direction on the distal end side of the lamp tube, and the connecting material is attached in such a manner as to cover the extended portion and the distal end portion of the lamp tube. Therefore, it becomes easy to connect the conductive portion of the lamp tube and the core wire, and it is not necessary to penetrate the conductive portion through the flat cable. As a result, the flat cable can be prevented from being damaged and deformed by the connection work, and the electrical connection between the core wire and the conductive portion can be ensured.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a main part of a backlight using a light source according to the present invention.
FIG. 2 is an enlarged vertical sectional view of a region II shown in FIG.
FIG. 3 is a schematic cross-sectional view showing a structure of a light source for a backlight using a conventional spacer-type lamp tube.
FIG. 4 is a schematic cross-sectional view showing a structure of a light source for a backlight using a conventional lead type lamp tube.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lamp tube 1a Conductive part 2 Core wire 2a Exposed core of extended part 3 Covering band 3a Covered band of extended part 4 Solder 10 Light guide plate 11 Tip part 20 Flat cable 100 Linear light source

Claims (4)

A lamp tube is placed on a flat cable in which a core wire is covered with an insulating band from both sides, and the conductive portion provided at the tip of the lamp tube and the core wire exposed at the tip of the flat cable are electrically connected. In the connected backlight source,
The flat cable extends in the length direction beyond the tip portion of the lamp tube, and the connecting member covers the core wire exposed from the insulating band at the extended portion and the tip portion of the lamp tube. A light source for backlight, characterized by being coated. The extension portion of the flat cable has the core wire exposed to leave the insulating band far from the lamp tube, and the connecting material covers the core wire of the extension portion and is deposited on the insulating band. The backlight light source according to claim 1. 3. The backlight light source according to claim 1, wherein solder is welded as the connecting material. A backlight comprising at least the light source according to any one of claims 1 to 3 and a light guide plate disposed with its end face facing the light source.

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