JP2003197017A - Planar lighting device and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar lighting device saving a space by simplifying a structure and to provide a small-size, light-weight, and highly reliable liquid crystal display device using the same. <P>SOLUTION: This planar lighting device is provided with a light guide plate 9, cold cathode lamps 7 disposed in its both sides and having a pair of respectively sealed discharging electrodes in the both end parts, a lead wire 12 connected to the discharging electrodes and supplying discharging power to the discharging electrodes, a holder 13 covering and insulating the connecting part between the discharging electrodes and the lead wire 12, and a backlight case 10 retaining the light guide plate 9, the cold cathode lamps 7, and the holder 13. This system is also provided with a projection 13a extending from the holder 13 and insulating between the lead wire 12 and the backlight case 10. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar lighting device, and more particularly to a structure of a planar lighting device used as a backlight of a display such as a liquid crystal display device. .

[0002]

2. Description of the Related Art The structure of a conventional liquid crystal display device using such a surface illumination device will be described. FIG. 5 is an exploded perspective view showing an assembly structure of a conventional liquid crystal display device.
As shown in the figure, in the conventional liquid crystal display device, a cold cathode discharge lamp 7 having, for example, a substantially U shape is arranged on the side surface of the light guide plate 9. The cold cathode discharge lamp 7 has a pair of discharge electrodes sealed at both ends thereof. Then, lead wires 12 for supplying electric power for discharge to the discharge electrodes are attached to the discharge electrodes, respectively. Also,
The periphery of the connection portion between the discharge electrode and the lead wire is covered with a holder 13 for insulation.

Further, a reflection sheet 11 for reflecting light in a specific direction is provided so as to cover the cold cathode discharge lamp 7 and the light guide plate 9 from the lower surface and the side surface, and the cold cathode discharge is further provided outside thereof. A backlight case 10 that evenly diffuses and dissipates heat generated from the lamp 7 is provided. The backlight case 10 also serves to hold the cold cathode discharge lamp 7, the light guide plate 9, the reflection sheet 11, and the holder 13. The diffuser plate 1, the prism lens sheet 2, and the diffuser plate 3 are superposed on the upper surface of the light guide plate 9 as optical sheets.

The above-mentioned structure has the frame 5 from the upper side.
Covered and retained. Further, the liquid crystal display panel 4 is arranged on the upper side of the frame 5, and is covered with a shield case 6 for the purpose of protecting it and electrically shielding it. An FPC (flexible substrate) 8 for transmitting a liquid crystal display panel drive signal extends from the side of the liquid crystal display panel 4.

Regarding the cold cathode discharge lamp 7 used in such a liquid crystal display device, the brightness, the quantity used, etc. are determined by the specifications of the liquid crystal display device. Further, the positional relationship among the frame 5, the cold cathode discharge lamp 7, the light guide plate 9, the backlight case 10, the lead wire 12, and the lead wire routing path determines the outer shape of the liquid crystal display device.

[0006]

However, in the lead wire routing path provided inside or outside the liquid crystal display device, a lead wire fixing portion or a lead wire fixing portion is provided in order to prevent interference with metal parts and floating of the lead wire. It is necessary to provide a protection part. Here, FIG. 6 is a bottom view of the conventional liquid crystal display device. Further, FIG. 7 is a sectional view, and FIG.
A-a cross section, and FIG. 7B shows a bb cross section.
As shown in each drawing, the lead wire routing path is provided with a lead wire fixing portion 10a having a substantially L-shaped cross section and a substantially flat plate-shaped protection portion 10b. These lead wire fixing parts 1
0a and the protection portion 10b need to be made of an insulating material (for example, a resin material) in terms of safety measures.

However, in order to provide a resin part, which is an insulator, in the backlight case 10 made of a metallic material, there is a restriction due to the mold structure in the place where it can be arranged. Alternatively,
In order to secure the resin strength, a certain size is required in order to provide the lead wire fixing portion and the protection portion as a part of the frame 5 made of a resin material. For this reason,
A space larger than the lead wire diameter, for example, a space larger than the wire diameter +1.6 mm is required, which has been a factor in increasing the size of the liquid crystal display device.

In view of the above problems, the present invention provides a planar lighting device having a simplified structure to save space, and a smaller, lighter and more reliable liquid crystal display device using the same. The purpose is to do.

[0009]

In order to achieve the above object, according to the present invention, a light guide plate and a pair of discharge electrodes disposed on the side surface or the back surface of the light guide plate and sealed at both ends are provided. A cathode discharge lamp, a lead wire connected to the discharge electrode for supplying electric power for discharge to the discharge electrode, and a holder for covering and insulating the connecting portion between the discharge electrode and the lead wire, In a planar lighting device provided with a light plate, a holding means for holding the cold cathode discharge lamp, and the holder, a projection extending from the holder and insulating between the lead wire and the holding means is provided. To do.

Further, a frame of an insulator for holding the light guide plate, the cold cathode discharge lamp and the holder is provided opposite to the holding means, and between the projection extending from the holder and the projection extending from the frame, The lead wire is fixed. Further, the holder is made of an elastic body.

A liquid crystal display device is provided in which a liquid crystal display panel is arranged on the surface side of the light guide plate in the planar lighting device.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing an assembly structure of a liquid crystal display device using the planar lighting device of the present invention. Here, the case of a 9.5 type liquid crystal display device is shown. 2 is an enlarged view of part A of FIG.
The state of the holder and its surroundings is shown.

In each drawing, a cold cathode discharge lamp 7 (not shown here) is arranged on the side surface (or back surface) of the light guide plate 9. The cold cathode discharge lamp 7 has a pair of discharge electrodes sealed at both ends thereof. Then, lead wires 12 for supplying electric power for discharge to the discharge electrodes are connected to the discharge electrodes. In addition, the connecting portion between the discharge electrode and the lead wire 12 has a holder 13 for insulation.
Are each covered with.

Further, a reflection sheet 11 (not shown here) for reflecting light in a specific direction is provided so as to cover the cold cathode discharge lamp 7 and the light guide plate 9 from the lower surface and the side surface, and further outside thereof. Is a backlight case 10 that evenly diffuses and dissipates heat generated from the cold cathode discharge lamp 7.
Is provided. The backlight case 10 also serves to hold the cold cathode discharge lamp 7, the light guide plate 9, the reflection sheet 11, and the holder 13. The diffuser plate 1, the prism lens sheet 2, and the diffuser plate 3 are superposed on the upper surface of the light guide plate 9 as optical sheets.

The above structure is covered with an insulating frame 5 from the upper side. Further, the liquid crystal display panel 4 is arranged on the upper side (front surface side) of the frame 5, and a shield case 6 is provided for the purpose of protecting and electrically shielding the liquid crystal display panel 4.
Is covered by. An FPC (flexible substrate) 8 for transmitting a liquid crystal display panel drive signal extends from the side of the liquid crystal display panel 4. The lead wire 12 immediately after coming out of the holder 13 is fixed to the lead wire fixing portion 10 a of the backlight case 10.

FIG. 3 is a diagram showing the structure of the holder.
The figure (a) is a front view, the figure (b) is a left side view, the figure (c) is a right side view, the figure (d) is a plan view, and the figure (e) is a bottom view, respectively. There is. However, the front surface in FIG. 1 is a flat surface in FIG. 1 or FIG. The holder 13 is made of, for example, an elastic body such as synthetic rubber, and has a structure as shown in FIG. That is, it has an inverted L shape when viewed from the front, and two holes 14 for inserting and supporting the end portion of the cold cathode discharge lamp 7 are formed on the right side surface. Further, a hole 15 through which the lead wire 12 is led out is formed on the lower surface, and a projection 13a extends from the flat end (the lower end of the side surface in FIG. 1 or 2).

FIG. 4 is a sectional view of the present liquid crystal display device as seen from the lamp side. As shown in the figure, by providing the holder 13 with the above-mentioned protrusion 13a, the lead wire 12 is arranged inside the holder 13, and the lead wire 12 can be arranged and protected only in the space occupied by the lead wire diameter. Become. In addition, the protrusion 5a extending downward from the peripheral edge of the frame 5
The position of the lead wire 12 is provided by providing (indicated by hatching), arranging this at a position facing the protrusion 13a with the lead wire 12 sandwiched between them, and further enclosing it from the side surface with a backlight case 10 that fits with the holder 13. It can be fixed.

Further, when two cold cathode discharge lamps 7 are vertically arranged as in the present embodiment, the lower cold cathode discharge lamp 7 is arranged one step lower than the light guide plate 9 in particular. It is difficult to provide the lead wire fixing portion 10a and the protective portion 10b made of a resin material on the backlight case 10. By adopting this embodiment, it is possible to reduce the die cost and the manufacturing cost.

Here, the sizes and materials of the components used in this embodiment are summarized below. [Part name] [Outer size] [Material] Diffusion sheet 1,3 Vertical 129 mm × 221 mm wide × 0.2 mm thick PET lens sheet 2 129 mm long × 221 mm wide × 0.2 mm thick PET reflective sheet 11 222 mm long × 148 mm wide × 0.2mm thick PET frame 5 148mm long x 227mm wide x 10mm thick Polycarbonate sealed case 6 Vertical 149mm x horizontal 228mm x thickness 0.4mm Aluminum hot dip plated light guide plate 9 132mm long x 214mm wide x 4mm acrylic acrylic light case 10 Length 225 mm x Width 146 mm x Height 8 mm x Thickness 0.5 mm Aluminum LCD display panel 4 Height 136 mm x Width 221 mm-Cold cathode discharge lamp 7 Length 217 mm x Diameter 2.2 mm-Lead wire 12 Diameter 1.6 mm-Holder 13 Length 8 mm × Horizontal 7 mm × Height 7 mm − Protrusion 13a Vertical 2 mm × Horizontal 3 mm × Thickness 0.5 mm −

The present invention can be applied to liquid crystal panels of any size, and is 9.5 as shown in this embodiment.
Type liquid crystal display device is not limited. Further, the planar lighting device of the present invention can also be applied as a front light.

Further, the holding means referred to in the claims is
It corresponds to the backlight case in the embodiment.

[0022]

As described above, according to the present invention,
A planar lighting device with a simplified structure to save space.
Further, it is possible to provide a smaller, lighter and highly reliable liquid crystal display device using the same.

Specifically, in the present invention, the holder for supporting the cold cathode discharge lamp not only insulates the discharge electrode of the cold cathode discharge lamp and the power supply lead wire connection portion, but also the power supply lead wire and the back. It also has a structure that insulates it from the light case. That is, the lead wire routing path can be arranged regardless of the material of the member surrounding the lead wire.

That is, it is possible to save the labor such as providing a lead wire protection portion on the frame or the backlight case, and to simplify the structure accordingly, and to protect and fix the lead wire in the space of the lead wire diameter for feeding. Because the function is achieved,
Space saving of the liquid crystal display device can be achieved at the same time. Therefore, it contributes greatly to the provision of a more compact and lightweight liquid crystal display device having high reliability.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an assembly structure of a liquid crystal display device of the present invention.

FIG. 2 is an enlarged view of part A in FIG.

FIG. 3 is a diagram showing a structure of a holder.

FIG. 4 is a cross-sectional view of the liquid crystal display device of the present invention viewed from the lamp side.

FIG. 5 is an exploded perspective view showing an assembly structure of a conventional liquid crystal display device.

FIG. 6 is a bottom view of a conventional liquid crystal display device.

7 is a sectional view of a predetermined portion of FIG.

[Explanation of symbols]

1,3 diffuser 2 Prism lens sheet 4 LCD display panel 5 frames 6 shield case 7 Cold cathode discharge lamp 8 FPC 9 Light guide plate 10 backlight case 11 Reflective sheet 12 lead wire 13 holder

Claims (4)

[Claims] 1. A light guide plate, a cold cathode discharge lamp having a pair of discharge electrodes, which is disposed on a side surface or a back surface of the light guide plate and is sealed at both ends thereof, and is connected to the discharge electrode and is connected to the discharge electrode. A lead wire for supplying electric power for discharge, and a holder for covering and insulating a connecting portion between the discharge electrode and the lead wire, and a holder for holding the light guide plate, the cold cathode discharge lamp, and the holder. A planar illuminating device including means, wherein the planar illuminating device is provided with a protrusion that extends from the holder and insulates between the lead wire and the holding means. 2. A frame of an insulator that holds the light guide plate, the cold cathode discharge lamp, and the holder opposite to the holding means, and between the projection extending from the holder and the projection extending from the frame, The planar lighting device according to claim 1, wherein the lead wire is fixed. 3. The planar lighting device according to claim 1, wherein the holder is made of an elastic body. 4. A liquid crystal display device, wherein a liquid crystal display panel is arranged on the front surface side of the light guide plate in the planar lighting device according to claim 1.