JP2001222231A - Plane display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plane display device which is capable of completely taking countermeasures against electromagnetic waves. SOLUTION: An inductor 58 which is a nonlinear element allowing the easier passage of lower frequencies is disposed at a PCB 12 and is provided with a metallic connecting member 60 for connecting the inductor 58 and a GND line of the PCB 12 and electrically connecting the inductor 58 and a metallic bezel cover 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device in which a display cell, a circuit board for driving the display cell, a backlight and the like are made of metal and housed in a bezel cover.

[0002]

2. Description of the Related Art The structure of a liquid crystal display device 100 which is one of the flat display devices will be described with reference to FIG.

The liquid crystal panel 2 is composed of a liquid crystal cell 4 and a backlight 6 laminated. On the signal line side of the liquid crystal cell 4, a TCP having a signal line driver IC 8 is provided.
A plurality of (tape carrier packages) 10 are connected, and a circuit board (hereinafter, referred to as a PCB) 12 for a signal line driver is connected to the plurality of TCPs 10. Also,
On the scanning line side of the liquid crystal cell 4, a scanning line driver IC 14
Is connected to the PCB 16 on the scanning line driver side.

[0004] A frame-shaped metal bezel cover 18 is put on the upper surface of the liquid crystal panel 2 via four rubbers 20 as cushioning materials. On the lower surface of the liquid crystal panel 2, a frame 22 made of a frame-shaped synthetic resin is overlapped, and is fixed together with the bezel cover 18 with screws 24. Further, the PCB 12 for the signal line driver is bent toward the lower surface side of the frame 22 and screwed with screws 26.

[0005]

By the way, the PCB 12 and the bezel cover 18 are connected to increase the strength of the liquid crystal panel 2 and to take measures against radio waves of the PCB 12. There are the following two connection methods.

A first method is to screw the PCB 12 and the bezel cover 18 with screws. In this method, the bezel cover 18 and the PCB 12 are electrically connected. However, according to this method, the degree of freedom of the PCB 12 is reduced, which may lead to deterioration in strength.

In the second method, as shown in FIG. 7, a connecting member 2 made of a metal plate is used to increase the degree of freedom of the PCB 12.
8 connects the PCB 12 and the bezel cover 18.

The connecting member 28 is formed of metal (copper) to be mounted on the PCB 12.
In order to mount on the CB 12, it is necessary to provide the mounting land 30 on the PCB 12.

The mounting land 30 and the PCB 12
Is connected to the ground potential (GND line), the bezel cover 18 and the PCB 12 are electrically connected. For this reason, there is no problem with respect to the ground potential, but there is a problem that high-frequency noise flows at the same time and radio wave measures are insufficient.

On the other hand, when the mounting land 30 is a floating land, that is, the GND line of the PCB 12 is in a non-conductive state, the bezel cover 18 and the PCB 12 are electrically non-conductive. Therefore, high-frequency noise does not flow and radio wave countermeasures can be taken, but there is a problem that ground potential cannot be obtained.

As described above, conventionally, there is a problem that if the bezel cover 18 and the PCB 12 are electrically conductive, the measures against radio waves are insufficient, and if the conductive state is not conductive, measures against the ground potential are insufficient. .

Accordingly, the present invention has been made in view of the above problems, and has as its object to provide a flat panel display device capable of completely taking measures against radio waves.

[0013]

According to a first aspect of the present invention, there is provided a flat panel display device in which a display cell, a circuit board for driving the display cell, a backlight, and the like are housed in a metal bezel cover. A flat surface provided with a metal connection member for connecting one end of the non-linear element which easily passes to the GND line of the circuit board and electrically connecting the other end of the non-linear element and the bezel cover. A display device.

The invention according to claim 2 is the flat display device according to claim 1, wherein the connection member is a metal plate that connects the circuit board and the bezel cover.

The invention according to claim 3 is the flat display device according to claim 1, wherein the connection member is a screw for fixing the circuit board to the bezel cover.

According to a fourth aspect of the present invention, there is provided the flat display device according to any one of the first to third aspects, wherein the non-linear element is an inductor.

According to a fifth aspect of the present invention, there is provided the flat display device according to any one of the first to fourth aspects, wherein the non-linear element cuts a specific frequency.

According to a sixth aspect of the present invention, the non-linear element is provided on the circuit board.
It is a flat display device of description.

In the flat display device of the present invention, the metal bezel cover and the GND line of the circuit board are connected via a non-linear element. This non-linear element is capable of conducting because the lower the frequency, the easier it is to pass.However, the non-linear element is non-conductive at a high frequency where noise is likely to occur, so that noise may leak from the display cell to the outside. Absent.

The connection member may be formed of a metal plate for connecting the circuit board and the bezel cover, or may be realized by screws for fixing the circuit board to the bezel cover.

The nonlinear element can be realized by an inductor.

Further, if the frequency at which the noise occurs is known, the frequency may be cut by the nonlinear element.

[0023]

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. In addition,
The liquid crystal display device 50 of the present embodiment has substantially the same structure as the liquid crystal display device 100 described in the section of the related art, and therefore the same structure and components will be described using the same reference numerals.

FIG. 1 is a bottom view of a liquid crystal display device 50 of the present embodiment, and FIG. 2 is an enlarged bottom view of a main part thereof. FIG. 3 is a sectional view taken along line AA in FIG.

As shown in FIG. 1, the TCP 10 provided in the liquid crystal cell 4 is folded back on the lower surface side of the frame 22, and the PCB 12 for the signal line driver is provided on the bottom surface side of the frame 22.
Is located. The left side of the PCB 12 is screwed at two places with screws 52, 52.

On the other hand, a GN
A through hole 54 connected to the D line is provided.
A mounting land 56 is provided on the right side of the through hole 54. Then, the through hole 54 and the mounting land 5
Inductor (coil) which is a nonlinear element between 6 and
58 are provided, and are electrically connected to the through holes 54 and the mounting lands 56.

On the mounting land 56, as shown in FIG.
One end of the plate-shaped connection member 60 is soldered. The other end of the connection member 60 is bifurcated and can be screwed. The other end of the connection member 60 is screwed to the bezel cover 18 and the frame 22 by a screw 62 as shown in FIG. The connection member 60 is formed of metal (copper) to be mounted on the PCB 12, and by doing so, the PCB 12 is fixed to the frame 22 at two places with the screws 52 and is also fixed to the connection member 60. , Are fixed at three places in total. As a result, the PCB 12 is rectangular and is fixed at both ends where the shift amount at both ends of the long side is the largest.
Since the right side is fixed by the connection member 60, the PCB 12
Can be reduced, the degree of freedom of the PCB 12 can be guaranteed, and the strength does not deteriorate.

As shown in FIG. 3, by inserting a metal bezel cover 18 between the screw 62 and the connecting member 60, the metal bezel cover 18 serves as a washer, and the screw 62 is loosened. Can be alleviated.

The inductor 58, which is a non-linear element,
As an example, a laminated type inductor can be considered. In addition to the inductor, a ferrite may be laminated on a conductor.

FIG. 4 shows the relationship between the impedance of the inductor 58 of this nonlinear element and the frequency characteristic.

As shown in this figure, although it is electrically conductive at low frequencies, it has high impedance at high frequencies and is non-conductive. As a result, the circuit becomes conductive with respect to the ground potential, but becomes substantially non-conductive with respect to high frequency potential such as noise, so that noise does not leak from the PCB 12 to the outside. Therefore, radio wave measures are effective.

(Second Embodiment) The difference between this embodiment and the first embodiment is that the bezel is not fixed to the metal bezel cover 18 via the connecting member 60 but is directly It is fixed to the cover 18.

Even with this fixing method, the provision of the inductor 58, which is a non-linear element, allows only low frequencies to be in a conducting state and high frequencies to be in a non-conducting state, thus making it possible to effectively take measures against radio waves.

(Third Embodiment) In the above embodiment, a non-linear element acting as a low-pass filter is used. For example, if a frequency at which noise occurs can be specified, a non-linear element which cuts only that frequency is used. May be used.

[0035]

As described above, according to the flat display device of the present invention, a non-linear element that passes more easily at a lower frequency is provided, so that the GN of the bezel cover and the circuit board can be reduced at a lower frequency.
D is in a conductive state, which leads to strengthening of GND and high impedance at high frequencies, so that electromagnetic measures can be taken reliably.

Also, since the connecting member connects the metal bezel cover and the circuit board, the mechanical strength is also improved.

Further, if the frequency at which noise occurs is known, the frequency may be cut by the nonlinear element.

[Brief description of the drawings]

FIG. 1 is a bottom view of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is an enlarged bottom view of a main part in the same manner.

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a graph showing impedance and frequency characteristics of a nonlinear element.

FIG. 5 is an enlarged bottom view of a main part of the liquid crystal display device of the second embodiment.

FIG. 6 is an exploded perspective view of the liquid crystal display device.

FIG. 7 is an enlarged bottom view of a main part of a conventional liquid crystal display device.

[Description of Signs] 2 Liquid crystal panel 4 Liquid crystal cell 6 Backlight 8 IC 10 TCP 12 PCB 18 Bezel cover 22 Frame 50 Liquid crystal display device 54 Through hole 56 Mounting land 58 Inductor 60 Connection member 62 Screw

Claims (6)

[Claims] 1. A flat panel display device in which a display cell, a circuit board for driving the display cell, a backlight, and the like are housed in a metal bezel cover, wherein one end of a non-linear element which is more likely to pass as a signal of lower frequency passes, and the circuit board And a metal connection member for electrically connecting the other end of the non-linear element and the bezel cover to each other. 2. The flat display device according to claim 1, wherein the connection member is a metal plate for connecting the circuit board and the bezel cover. 3. The flat display device according to claim 1, wherein the connection member is a screw for fixing the circuit board to the bezel cover. 4. The flat display device according to claim 1, wherein the non-linear element is an inductor. 5. The flat display device according to claim 1, wherein the non-linear element cuts a specific frequency. 6. The flat display device according to claim 1, wherein the non-linear element is provided on the circuit board.