JP2003330378A - Electric appliance provided with cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the reduction of luminance caused by conductive front glass to realize a very high image quality without requiring an electromagnetic shield constituted of a conductive metallic housing and the conductive front glass, for intercepting an electromagnetic disturbing wave generated from a plane display panel in an electric appliance like a plasma display panel. <P>SOLUTION: The electric appliance has a first circuit board 13c and a second circuit board 13b electrically connected through a cable 15c. A ground of the first circuit board 13c and that of the second circuit board 13b are connected to an FG 11 formed by a conductive metallic chassis, in both end parts of the cable 15c. The cable 15c is arranged in the vicinity of the FG 11 so as to lie along the FG 11. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric device equipped with a cable, and more particularly to a ground structure for reducing unnecessary radiation noise in a display device such as a television or a display having a matrix drive type flat display panel, and In particular, the present invention relates to an electric device provided with a cable aiming at improvement of characteristics against noise in a high frequency region.

[0002]

2. Description of the Related Art In a conventional display device having a matrix drive type flat display panel (hereinbelow, described as a plasma display panel display device), pixels are arranged in a matrix on the flat display panel.

A conventional plasma display panel (hereinafter referred to as "PDP") display device will be described below with reference to the drawings. FIG. 15 is a perspective view for explaining the structure of a conventional PDP, and FIG. 16 is a perspective view for explaining the electrode structure of the conventional PDP.

As shown in FIG. 15, a chassis 11 as a holding plate is arranged on the non-display surface side of the PDP panel 10 made of a glass substrate or the like, and holds the PDP panel 10. The chassis 11 is a conductive metal plate made of aluminum and has a frame ground (hereinafter,
(Referred to as “FG”). 12 is PDP
It is a stand for vertically supporting the panel 10, and has a support base 12a and a stand column 12b.

The driver drive circuits 13a and 13b, the relay circuit board 13c, and the discharge control circuit 13d are mounted on the chassis 11
It is located on the back side of. In the scan and sustain electrodes, the drive signal generated from the driver drive circuit 13a is transmitted to the electrode 14 of the PDP panel 10 by the flexible cable 15a. In the writing electrode, the discharge control circuit 1
The high frequency signal generated in 3d is the flexible cable 1
5d is transmitted to the relay circuit board 13c, and the flexible cable 15c is used to drive the driver drive circuit 13b.
And a drive signal is generated in the driver drive circuit 13b and transmitted to the electrode 14 of the PDP panel 10 by the flexible cable 15b. The signal ground of the driver driving circuit 13a for the scan and sustain electrodes (hereinafter,
"SG") is at point A, SG of the driver driving circuit 13b of the writing electrode is at point B, and the relay circuit board 13c
Is at point C, and the discharge control circuit 13d is at point D.
Is grounded to the chassis 11.

As shown in FIG. 16, in the PDP panel 10 in which the chassis 11 is arranged on the non-display surface side, the sustain electrodes 14a and the scanning electrodes 14b are provided on the front glass substrate 20 on the display surface side.
Is provided, and the writing electrode 14c is formed on the rear glass substrate 24 facing the same. A dielectric layer 21 is formed on the front glass substrate 20. A partition 22 for separation is formed on the write electrode 14c so that the plasma discharge does not affect the adjacent electrode. Red 23a, blue 23b, and green 23c phosphors are separately coated on the write electrode 14c, and a discharge space is formed between the front glass substrate 20 on the display surface side and the rear glass substrate 24 facing the front glass substrate 20. Gas is enclosed in the driver drive circuit 13
The cells selected by a and 13b are plasma-discharged, and the respective phosphors of red 23a, blue 23b, and green 23c emit light to form a color image.

However, regarding the PDP as described above, when the item of unnecessary radiation of the radio wave based on the standard of VCCI (Voluntary Control Council for Radio Interference such as Information Processing Equipment) is examined, 100 V is applied to the sustain electrode 14a and the scan electrode 14b.
A signal having a pulse voltage of pp to 200 Vp-p is applied, and 30 Vp-p to 100 V is applied to the write electrode 14c.
Since a signal of pp pulse voltage is applied and electromagnetic interference waves such as the fundamental wave of the above signals and harmonics thereof are radiated into the air, the level of unnecessary radiation noise is large, and other electronic devices are adversely affected electromagnetically. There was a challenge to exert.

In the conventional PDP, with respect to the large unnecessary radiation noise from the cable portion, the reason for the occurrence thereof will be considered by taking the flexible cable (for writing electrode driver) 15c as an example. FIG. 17 is an explanatory diagram perspectively viewed from the CS cross section for explaining the flow of the high frequency current in the cable portion of the conventional PDP. Flexible cable 15c from the relay circuit board 13c to the driver drive circuit 13b
When the high-frequency signal 40 passes through, the return current 41 of the high-frequency signal 40 is generated in the chassis 11 which is the FG, passes through the relay circuit board 13c at the point C where the SG and the FG are connected, and the driver drive circuit 13b. Since it passes through the point B, the high frequency current path 42 in the figure is formed. 61 is
It is a ground line in the relay circuit board 13c and the driver drive circuit 13b. This large loop radiates unwanted radiation noise into the air. Although not shown, a high-frequency current induced in the power supply line by the relay circuit board 13c or the driver drive circuit 13b passes through the flexible cable 15c to generate a large loop equivalent to the high-frequency current path 42 for the high-frequency signal 40. However, unnecessary radiation noise is radiated into the air.

As a solution to this problem, as shown in FIG.
The stand 12 is supported by a conductive metal housing 30 made of aluminum and a conductive front glass 31 on the surface of which a conductive film or conductive metal mesh formed by silver vapor deposition is formed for the purpose of blocking electromagnetic interference waves. In addition, by forming an electromagnetic shield around the PDP panel 10 in which the chassis 11 is arranged on the non-display surface side, an electromagnetic interference wave is cut off.

[0010]

However, in the above-mentioned electromagnetic shield structure of the PDP, since the conductive front glass 31 is arranged on the display surface side of the PDP, unless a colorless and transparent conductor is used, There is a problem that the visible light emitted by the discharge is blocked and the brightness is reduced. In addition, since the transparent conductive film has a large electric resistance, there is a problem that it is not possible to sufficiently block electromagnetic interference waves.

In view of the above-mentioned problems, the present invention eliminates the need for a conductive metal casing for blocking electromagnetic interference waves generated from a flat display panel and an electromagnetic shield for the conductive front glass, and the brightness of the conductive front glass. It is an object of the present invention to provide an electric device equipped with a cable, which can provide a display device that can suppress the deterioration and can achieve a significantly high image quality.

[0012]

In order to achieve this object, the present invention relates to a device in which a first circuit board and a second circuit board are electrically connected via a cable, and at both ends of the cable. , The ground of the first circuit board and the ground of the second circuit board are connected to FGs each made of a conductive metal chassis, and the cable is connected to the F
It is arranged so as to be close to this FG so as to follow the G.

With this structure, the high-frequency current path formed by the high-frequency signal flowing through the cable and the return current flowing through the FG can be minimized, and the generation of electromagnetic interference waves from the cable portion where unnecessary radiation noise is particularly large is suppressed. it can.

Further, according to the present invention, in a device in which the first circuit board and the second circuit board are electrically connected via a cable, the ground lines of the cable are electrically conductive at both ends of the cable. The cable is connected to a frame ground made of a metal chassis, and the cable is arranged close to the frame ground along the frame ground.

With this configuration, the high-frequency current path formed by the high-frequency signal flowing through the cable and the return current flowing through the FG can be minimized, and the generation of electromagnetic interference waves from the cable portion where unwanted radiation noise is particularly large is suppressed. it can.

In the present invention, preferably, the ground line of the cable and the FG are connected by a screw member made of a conductive metal, a spring member, or a gasket member. Further, preferably, the cable is connected to the FG side portion of the circuit board.

Further, according to the present invention, in a device in which a first circuit board and a second circuit board are electrically connected via a cable, the cable in the first and / or second circuit board is connected. At the end on the side where the ground of the first and / or the second circuit board is connected to the FG made of a conductive metal chassis by a ground member made of a conductive metal, and the cable extends along the ground member. It is arranged so as to be arranged close to this FG along the FG.

With this configuration, the high-frequency current path formed by the high-frequency signal flowing through the cable and the return current flowing through the FG can be minimized, and the generation of electromagnetic interference waves from the cable portion where the unwanted radiation noise is particularly large is suppressed. it can.

In the present invention, the ground member is preferably the same member as the FG. Further, the present invention is a device in which a first circuit board and a second circuit board are electrically connected via a cable, in which a cable gland member made of a conductive metal is arranged along the cable, At both ends, the ground of the first circuit board and the ground of the second circuit board and / or the ground line of the cable are connected to FGs each made of a conductive metal chassis, and the cable ground member is The FG is connected to the FG.

With this configuration, the high-frequency current path formed by the high-frequency signal flowing through the cable and the return current flowing through the FG can be minimized, and the generation of electromagnetic interference waves from the cable portion where unnecessary radiation noise is particularly large is suppressed. it can.

In the present invention, the cable gland member is preferably the same member as the FG. The present invention may also be arranged such that the cable gland member has a hole, and the cable is arranged through this hole.

With this configuration, the high-frequency current path formed by the high-frequency signal flowing through the cable and the return current flowing through the FG can be minimized, and the generation of electromagnetic interference waves from the cable portion where unnecessary radiation noise is particularly large is suppressed. it can.

According to the present invention, the cable gland member has a concave portion, and the end portions of the first and / or the second circuit board are inserted into the concave portion of the cable gland member to form the first and / or the second circuit board. The ground of the circuit board and the cable ground member are connected to each other.

With this configuration, after facilitating the connection between the circuit board ground and the cable ground,
The high-frequency current path formed by the high-frequency signal flowing through the cable and the return current flowing through the FG can be minimized, and in particular, the generation of electromagnetic interference waves from the cable portion having large unnecessary radiation noise can be suppressed.

In the present invention, preferably the cable is F
It is fixed to G. Further, preferably, a guide for arranging the cable is formed on the FG, and the guide is a groove along the cable or has a hole for passing the cable. Furthermore, preferably, the cable is a flexible cable.

According to the present invention, the ground of the first circuit board and the power source are electrically connected via the first capacitor near the end of the cable, and the ground of the second circuit board is connected. The power supply is electrically connected via the second capacitor.

With this structure, the high-frequency current induced in the power supply line flows into the FG at both ends of the cable, and the high-frequency current passing through the power supply line of the cable can be minimized, especially from the cable portion where the unnecessary radiation noise is large. It is possible to suppress the generation of electromagnetic interference waves.

In the present invention, preferably, a matrix drive type flat display panel having a plurality of electrodes,
And a driver driving circuit for the flat display panel.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of the present invention will be described with reference to FIGS.
A color television having a PDP is exemplified as the display device.

FIG. 1 is a perspective view for explaining the configuration of a PDP as an electric device provided with a cable according to the first embodiment of the present invention, and the electromagnetic interference wave of a color television as an embodiment is unnecessary. Only the structures closely related to radiation are shown. 2 is a perspective view for explaining the electrode structure of the PDP of FIG. 1, and FIG. 3 is an explanatory view perspectively viewed from the CS cross section for explaining the flow of the high frequency current in the cable portion of the PDP of FIG.

In FIG. 1, the color television of the present embodiment has a PDP panel 10 which is a matrix drive type flat display panel having a plurality of electrodes 14, for example, a glass substrate, and a non-display surface of the PDP panel 10. A chassis 11 which is a holding plate which is arranged on the side and holds the PDP panel 10 is arranged. 12 is PD
It is a stand for vertically supporting the P panel 10, and has a support 12a and a stand column 12b. The driver drive circuits 13a and 13b, the relay circuit board 13c, and the discharge control circuit 13d are arranged on the rear surface side of the chassis 11. For the scan and sustain electrodes, the driver drive circuit 13a
The drive signal generated from the flexible cable 15a
Is transmitted to the electrode 14 of the PDP panel 10. In the writing electrode, the high frequency signal generated in the discharge control circuit 13d is transmitted to the relay circuit board 13c by the flexible cable 15d, transmitted to the driver drive circuit 13b by the flexible cable 15c, and the drive signal is generated in the driver drive circuit 13b. , Is transmitted to the electrode 14 of the PDP panel 10 by the flexible cable 15b.

As shown in FIG. 2, in the PDP panel 10, the sustain electrodes 14a are provided on the front glass substrate 20 on the display surface side.
The rear glass substrate 2 provided with the scanning electrodes 14b and facing each other
4 has a writing electrode 14c formed thereon. A dielectric layer 21 is formed on the front glass substrate 20. A partition 22 for separation is formed on the write electrode 14c so that the plasma discharge does not affect the adjacent electrode. On the write electrode 14c, red 23a, blue 23b, green 2
Discharge gas is sealed in the discharge space between the front glass substrate 20 on the display surface side and the rear glass substrate 24 facing the display surface side.
The cells selected by 3a and 13b are plasma-discharged,
The red 23a, blue 23b, and green 23c phosphors emit light to form a color image.

The chassis 11 is a conductive metal plate made of aluminum, for example, and functions as a frame ground (FG) in terms of an electric circuit. The signal ground (SG) of the driver driving circuit 13a for the scan and sustain electrodes is at point A, the SG of the driver driving circuit 13b for writing electrode is at point B, the relay circuit board 13c is at point C, and the discharge control circuit 1
3d is a point D, which is grounded to the chassis 11 which is an FG.

As shown in FIG. 3, the SG of the relay circuit board 13c, which is the first circuit board, and the SG of the driver drive circuit 13b, which is the second circuit board, are electrically conductive at both ends of the flexible cable 15c. By connecting the flexible cable 15c to the chassis 11 which is an FG using the sex screw 50 and arranging the flexible cable 15c close to the chassis 11 along the chassis 11, the high frequency signal 40 flowing through the cable 15c and the chassis 11 flow. The high frequency current path 42 formed by the return current 41 can be minimized. As a result, it is possible to suppress the generation of electromagnetic interference waves from the cable portion having particularly large unnecessary radiation noise.

Although not shown, the relay circuit board 13c is provided near the end of the flexible cable 15c.
Of the driver drive circuit 13b is electrically connected to the power supply line via a capacitor, and the SG of the driver driving circuit 13b is electrically connected to the power supply line via a capacitor, so that the high-frequency current induced in the power supply line is induced. Can flow into the FG at both ends of the flexible cable 15c. As a result, the high-frequency current passing through the power supply line of the flexible cable 15c can be minimized, and the generation of electromagnetic interference waves from the cable portion having particularly large unnecessary radiation noise can be suppressed.

As described above, the first circuit board is provided at both ends of the cable 15c for electrically connecting the relay circuit board 13c which is the first circuit board and the driver drive circuit 13b which is the second circuit board. And the ground of the relay circuit board 13c and the driver drive circuit 13b which is the second circuit board.
Of the conductive metal chassis 11 and the cables 15c are connected to the chassis 11 respectively.
The high-frequency current path 42 can be minimized and the electromagnetic interference wave can be suppressed by arranging it in close proximity to. Therefore, the conventional conductive metal casing and the conductive front glass electromagnetic shield as shown in FIG. 18 for blocking the electromagnetic interference wave generated from the flat display panel are unnecessary, and therefore, compared with the conventional method. Thus, it is possible to inexpensively manufacture a display device having a flat display panel, and it is possible to suppress a decrease in brightness due to the conductive front glass, and to realize a significantly high image quality.

In the first embodiment, the flexible cable 15c is arranged along the surface of the chassis 11 which is an FG. However, when the flexible cable 15c is fixed to the chassis 11, a high frequency current path is formed. Can be minimized, the path length can be made stable, and the generation of electromagnetic interference waves can be suppressed.

In the first embodiment, the flexible cable 15c for the writing electrode driver is described as an example of the cable, but the flexible cable for the scanning and sustaining electrodes, the flexible cable for the writing electrode, the relay circuit board. The same effect can be obtained by applying the same configuration to a cable such as a flexible cable for use.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. As the display device, a color television having a PDP is also exemplified.

FIG. 4 is an explanatory diagram perspectively viewed from the CS cross section for explaining the flow of the high frequency current in the cable portion of the PDP as the electric equipment provided with the cable of the second embodiment of the present invention. 1 shows only the structure deeply related to unnecessary radiation of electromagnetic interference waves of the color television as an embodiment. In the electric device provided with the cable of the second embodiment in FIG. 4, the ground lines of the flexible cable 15c are attached to the chassis 11 which is the FG by using the conductive screws 50 at both ends of the flexible cable 15c. The difference from the first embodiment shown in FIGS. 1 to 3 is that the connection is made.
SG of the relay circuit board 13c and the driver drive circuit 13b
SGs are connected to the chassis 11 which are FGs. 13c is a relay circuit board, 13b is a driver driving circuit, 40 is a high frequency signal, 41 is a return current, and 4
Reference numeral 2 is a high-frequency current path, which are the same as those in FIG.

In the first embodiment, the connection point between SG and FG is a portion where the wiring of the cable is concentrated on the circuit board, and a space for connecting SG and FG is required at this portion. On the other hand, here, as described above, by connecting the ground line of the cable 15c to the FG at both ends of the cable 15c, the circuit board 13c,
13b does not require a space for connecting SG and FG. Therefore, the high-frequency current path can be minimized, the generation of electromagnetic interference can be suppressed, and there is no need for a conductive metal housing and a conductive front glass to shield the electromagnetic interference generated from the flat display panel. Therefore, it is possible to manufacture a display device having a flat display panel at a low cost as compared with the conventional one, and it is possible to suppress a decrease in brightness due to the conductive front glass, and to realize a significantly high image quality.

The second embodiment has been described by taking as an example the case where the grant line of the flexible cable 15c and the chassis 11 are connected by the conductive screw 50 at both ends of the flexible cable 15c. Is fixed by a guide and then connected by another conductive metal member such as a conductive spring 51 as shown in FIG. 5 or a conductive gasket 52 as shown in FIG. 6,
Has the same effect. In these FIG. 5 and FIG.
13c is a relay circuit board, 13b is a driver drive circuit,
Reference numeral 40 is a high frequency signal, 41 is a return current, and 42 is a high frequency current path. In FIG. 5, the strip-shaped flexible cable 15c is fixed by the groove-shaped guide 53 by fitting the end portion thereof into the groove-shaped guide 53 provided on the chassis 11. In FIG. 6, the belt-shaped flexible cable 15c is fixed to the conductive gasket 52 by the hole-shaped guide 54 while being passed through the hole-shaped guide 54 provided in the chassis 11.

In the first and second embodiments, the flexible cable 15c is the relay circuit board 13c.
FG, that is, the case where the flexible cable 15c is connected to the side opposite to the chassis 11 of the relay circuit board 13c as shown in FIG. Produce the effect of.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG. As the display device, a color television having a PDP is also exemplified.

FIG. 8 is an explanatory diagram perspectively viewed from the CS cross section for explaining the flow of the high frequency current in the cable portion of the PDP as the electric equipment provided with the cable of the third embodiment of the present invention. 1 shows only the structure deeply related to unnecessary radiation of electromagnetic interference waves of the color television as an embodiment. The electric device provided with the cable of the third embodiment in FIG. 8 is the flexible cable 1 in the relay circuit board 13c and the driver drive circuit 13b.
At the end portion on the side to which 5c is connected, these relay circuit boards 13
The chassis 11 in which the SG of c and the SG of the driver drive circuit 13b are FGs with the ground plate 55 made of a conductive metal.
Is different from the second embodiment shown in FIG. 4 in that the flexible cable 15c is arranged along the ground plate 55.

As described above, at the end of the first and / or second circuit board 13c, 13b on the side to which the cable 15c is connected, the ground of the first and / or second circuit board 13c, 13b. Is connected to the chassis 11 with a ground plate 55 made of a conductive metal, and the cable 15c is arranged along the ground plate 55, so that the high-frequency current path 42 can be minimized and the generation of electromagnetic interference waves can be suppressed. . Therefore, the conventional conductive metal casing and the conductive front glass electromagnetic shield as shown in FIG. 18 for blocking the electromagnetic interference wave generated from the flat display panel are unnecessary, and therefore, compared with the conventional method. Thus, it is possible to inexpensively manufacture a display device having a flat display panel, and it is possible to suppress a decrease in brightness due to the conductive front glass, and to realize a significantly high image quality.

In the third embodiment, the case where the SG and FG are connected by the ground plate 55 made of a conductive metal has been described as an example. However, as shown in FIG. Even if the ground plate 56 is formed by a portion and SG and FG are connected at the end portion of the ground plate 56, the same effect is obtained.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIG. As the display device, a color television having a PDP is also exemplified.

FIG. 10 is an explanatory diagram perspectively viewed from the CS cross section for explaining the flow of a high frequency current in the cable portion of the PDP as an electric device equipped with the cable of the fourth embodiment of the present invention. 1 shows only the structure deeply related to unnecessary radiation of electromagnetic interference waves of the color television as an embodiment. In the display device according to the fourth embodiment in FIG. 10, a cable gland 57 made of a conductive metal is arranged along the flexible cable 15c, and the cable gland 57 is connected to the chassis 11 as the FG. A conductive gasket 52 is provided between the flexible cable 15c and the flexible cable 15c, which is different from the second embodiment shown in FIG. The SG of the relay circuit board 13c, the SG of the driver drive circuit 13b, and the cable gland of the flexible cable 15c are connected to the chassis 11 which is an FG. 13c is a relay circuit board, 13b is a driver drive circuit, 40 is a high frequency signal, 41 is a return current, and 42 is a high frequency current path, which are the same as those in FIG.

In this way, by disposing the cable gland 57 made of a conductive metal along the cable 15c and connecting the cable gland 57 to the chassis 11 as the FG, the high frequency current path 42 can be minimized and the electromagnetic field can be reduced. The generation of interfering waves can be suppressed. Therefore, in order to block the electromagnetic interference wave generated from the flat display panel, as shown in FIG.
As shown in Fig. 3, the conventional conductive metal casing and the electromagnetic shield by the conductive front glass are not required, and therefore, the display device having the flat display panel can be manufactured at a low cost as compared with the conventional method, and the conductive screen can be manufactured. It is possible to suppress the decrease in brightness due to the front glass, and to realize a very high image quality.

In the fourth embodiment, the case where the cable gland 57 made of a conductive metal is arranged has been described as an example. However, even if the cable gland 57 is formed by a part of the chassis 11 as the FG, the same is true. Produce the effect of.

Further, as the fourth embodiment, the case where the cable gland 57 made of a conductive metal is arranged on the back surface of the flexible cable 15c has been described as an example, but as shown in FIG. Even if the flexible cable 15c is arranged through the hole 58, the same effect can be obtained.

(Fifth Embodiment) The fifth embodiment of the present invention will be described with reference to FIG. As the display device, a color television having a PDP is also exemplified.

FIG. 12 is an explanatory diagram perspectively viewed from the CS cross section for explaining the flow of the high frequency current in the cable portion of the PDP as the electric equipment provided with the cable of the fifth embodiment of the present invention. 1 shows only the structure deeply related to unnecessary radiation of electromagnetic interference waves of the color television as an embodiment. In the electric device provided with the cable of the fifth embodiment in FIG. 12, the cable gland 57 has a recess 59, and the end of the relay circuit board 13c is inserted into the recess 59 of the cable gland 57 to form a relay circuit. Board 1
It is different from the fourth embodiment shown in FIG. 10 in that the SG of 3c and the cable gland 57 are connected.

In this way, by inserting the end portion of the relay circuit board 13c into the recess 59 of the cable gland 57 and connecting the SG of the relay circuit board 13c and the cable gland 57, the SG of the relay circuit board 13c is connected. The high-frequency current loop 42 can be minimized while improving the connectivity with the cable gland 57, and the generation of electromagnetic interference waves can be suppressed. Therefore, the conventional conductive metal casing and the conductive front glass electromagnetic shield as shown in FIG. 18 for blocking the electromagnetic interference wave generated from the flat display panel are unnecessary, and therefore, compared with the conventional method. Thus, it is possible to inexpensively manufacture a display device having a flat display panel, and it is possible to suppress a decrease in brightness due to the conductive front glass, and to realize a significantly high image quality.

(Sixth Embodiment) A sixth embodiment of the present invention will be described with reference to FIG. As the display device, a color television having a PDP is also exemplified.

FIG. 13 is a perspective view from the CS cross section for explaining the flow of a high frequency current in the cable portion of a PDP as an electric device equipped with the cable of the sixth embodiment of the present invention. 1 shows only the structure deeply related to unnecessary radiation of electromagnetic interference waves of the color television as an embodiment. The display device of the sixth embodiment in FIG. 13 differs from the display device of the fourth embodiment shown in FIG. 10 in that a cable gland 60 made of a conductive metal tape is adhered to the flexible cable 15c.
A conductive gasket 52 is provided between the flexible cable 15c and the cable gland 60. Both ends of the cable gland 60 are flexible cables 1
It is connected to the chassis 11 as the FG while being bent so as to project from 5c.

FIG. 14 shows a comparison of the radiation noise measurement results of the 42-inch PDP televisions of the conventional example shown in FIG. 15 and the sixth embodiment shown in FIG. The radiation noise was measured by setting the PDP television on a rotating table in an anechoic chamber, rotating the table, and measuring the maximum value of the electric field strength at a distance of 3 m for each frequency.

By bonding the cable gland 60 made of a conductive metal tape to the flexible cable 15c and connecting the cable gland 60 to the chassis 11 as the FG, the high frequency current path 42 can be minimized and the generation of electromagnetic interference waves can be prevented. Can be suppressed, and as shown in FIG.
The radiation noise level can be reduced as compared with the conventional case.

As described above, the cable gland 60 made of a conductive metal tape is arranged along the cable 15c, and the cable gland 60 serves as the chassis 11 as the FG.
By connecting to, the high-frequency current path 42 can be minimized and the generation of electromagnetic interference waves can be suppressed. Therefore, the conventional conductive metal casing and the conductive front glass electromagnetic shield as shown in FIG. 18 for blocking the electromagnetic interference wave generated from the flat display panel are unnecessary, and therefore, compared with the conventional method. Thus, it is possible to inexpensively manufacture a display device having a flat display panel, and it is possible to suppress a decrease in brightness due to the conductive front glass, and to realize a significantly high image quality.

In each of the above embodiments, the PD
Although P has been described, the present invention is not limited to this, and can be applied to all display devices having a matrix drive type flat display panel having a plurality of electrodes such as liquid crystal and other electric devices equipped with a cable. It can be applied and has the same effect.

In the above embodiment, the case of the chassis 11 made of aluminum is described as an example, but the present invention can be applied to a display device having a chassis made of other conductive material such as copper.

In the above embodiment, the chassis 11 is used.
Although FG is described as an example, it can be applied to a display device in which another conductive member functions as FG. Also,
In the above description, the 42-inch color television is described as an example, but the invention can be applied to display devices of other sizes.

[0064]

As described above, according to the present invention, the first
In a device in which the circuit board and the second circuit board are electrically connected via a cable, at both ends of the cable,
The ground of the first circuit board and the ground of the second circuit board are each made of a conductive metal chassis.
Since the cable is connected to G and the cable is arranged close to the FG along the FG, it is possible to minimize the high frequency current path formed by the high frequency signal flowing through the cable and the return current flowing through the FG. The generation of electromagnetic interference waves due to the drive signal radiated in the air from this high-frequency current path can be suppressed. Therefore, for example, a conductive metal casing for blocking electromagnetic interference waves generated from a flat display panel and an electromagnetic shield by a conductive front glass are not required, and a display device having a flat display panel is less expensive than a conventional one. Can be manufactured to
It is possible to suppress a decrease in brightness due to the conductive front glass, and it is possible to realize remarkably high image quality.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining the configuration of a PDP as an electric device according to a first embodiment of the present invention.

2 is a perspective view for explaining an electrode structure of the PDP of FIG.

FIG. 3 is a perspective view from the CS cross-section for explaining the flow of high-frequency current in the cable portion of the PDP of FIG.

FIG. 4 is a perspective view from the CS cross section for explaining the flow of a high-frequency current in a cable portion of a PDP as an electric device according to a second embodiment of the present invention.

FIG. 5 is a perspective view from a CS cross section for explaining a flow of a high frequency current in a cable portion in a modified example of the second embodiment.

FIG. 6 is a perspective view from a CS cross section for explaining a flow of a high frequency current in a cable portion in another modification of the second embodiment.

FIG. 7 is a CS diagram for explaining the flow of high-frequency current in the cable section in still another modification of the second embodiment.
Perspective view from cross section

FIG. 8 is a perspective view from a CS cross section for explaining a flow of a high frequency current in a cable portion of a PDP as an electric device according to a third embodiment of the present invention.

FIG. 9 is a perspective view from the CS cross section for explaining the flow of high-frequency current in the cable portion in the modification of the third embodiment.

FIG. 10 is a perspective view from a CS cross section for explaining a flow of a high frequency current in a cable portion of a PDP as an electric device according to a fourth embodiment of the present invention.

FIG. 11 is a perspective view from a CS cross section for explaining a flow of a high frequency current in a cable portion in a modification of the fourth embodiment.

FIG. 12 is a perspective view of a CS section for explaining the flow of a high frequency current in a cable portion of a PDP as an electric device according to a fifth embodiment of the present invention.

FIG. 13 is a perspective view of a CS cross section for explaining the flow of a high frequency current in a cable portion of a PDP as an electric device according to a sixth embodiment of the present invention.

14 is a graph showing the electric field strength of the noise level in the vertical direction, which is the electromagnetic interference reduction effect for the PDP of FIG.

FIG. 15 is a perspective view for explaining the configuration of a conventional PDP.

16 is a perspective view for explaining an electrode structure of the PDP of FIG.

17 is a perspective view from the CS cross section for explaining the flow of high-frequency current in the cable portion of the PDP of FIG.

FIG. 18 is a perspective view for explaining a conventional PDP casing structure.

[Explanation of symbols]

11 chassis 13b Driver drive circuit 13c relay circuit board 15c flexible cable 40 high frequency signal 41 Return current 42 High frequency current path 50 conductive screw

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5E321 AA01 CC22 GG09                 5G435 AA16 BB01 BB06 BB11 CC09                       EE04 EE34 EE47 GG34 KK09                       LL04 LL06 LL08

Claims (16)

[Claims] 1. In a device in which a first circuit board and a second circuit board are electrically connected via a cable, the ground of the first circuit board and the second circuit board are provided at both ends of the cable. A circuit board ground is connected to a frame ground made of a conductive metal chassis, and the cable is arranged close to the frame ground along the frame ground. Electrical equipment. 2. In a device in which a first circuit board and a second circuit board are electrically connected via a cable, a ground line of the cable is provided at both ends of the cable.
An electric device provided with a cable, each of which is connected to a frame ground made of a conductive metal chassis, and the cable is arranged close to the frame ground along the frame ground. 3. The cable according to claim 2, wherein the ground line of the cable and the frame ground are connected by a screw member made of a conductive metal, a spring member, or a gasket member. Electrical equipment. 4. The electric device provided with the cable according to claim 1, wherein the cable is connected to a portion of the circuit board on the frame ground side. 5. In a device in which a first circuit board and a second circuit board are electrically connected to each other via a cable, a portion of the first and / or second circuit board to which the cable is connected is connected. At the end, said first and / or second
The ground of the circuit board is connected to a frame ground made of a conductive metal chassis by a ground member made of a conductive metal, the cable is arranged along the ground member, and the frame is arranged along the frame ground. An electric device equipped with a cable characterized in that it is arranged close to the ground. 6. The electric device provided with the cable according to claim 5, wherein the ground member is formed of the same member as the frame ground. 7. In a device in which a first circuit board and a second circuit board are electrically connected via a cable, a cable gland member made of a conductive metal is arranged along the cable, At both ends, the ground of the first circuit board and the ground of the second circuit board and / or the ground line of the cable are connected to a frame ground made of a conductive metal chassis, respectively, and the cable ground member is provided. Is connected to the frame ground, and an electric device having a cable. 8. The electric device provided with a cable according to claim 7, wherein the cable ground member is formed of the same member as the frame ground. 9. An electric device with a cable according to claim 7, wherein the cable gland member has a hole, and the cable is arranged through the hole. 10. The cable gland member has a recess, and the end of the first and / or second circuit board is inserted into the recess of the cable gland member to form the first and / or second circuit board. 9. The electric device provided with the cable according to claim 7, wherein the ground and the cable ground member are connected to each other. 11. An electric device equipped with the cable according to claim 1, wherein the cable is fixed to a frame ground. 12. An electric device equipped with the cable according to claim 1, wherein a guide for arranging the cable is formed on the frame ground. 13. The electric device with a cable according to claim 12, wherein the guide is formed in a groove shape along the cable, or has a hole for passing the cable. 14. The cable according to claim 1, wherein the cable is a flexible cable.
An electric device equipped with the cable according to the item. 15. The ground of the first circuit board and the power supply are electrically connected via a first capacitor near the end of the cable, and the ground of the second circuit board and the power supply are connected to each other. An electrical device provided with the cable according to any one of claims 1 to 14, wherein the electrical device is electrically connected via a second capacitor. 16. The cable according to claim 1, further comprising a matrix drive type flat display panel having a plurality of electrodes, and a driver driving circuit for the flat display panel. Electrical equipment with.