JP2009223002A - Plasma display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display device capable of reducing electromagnetic interfering waves caused by a drive current flowing in a plasma display panel. <P>SOLUTION: The plasma display device includes a shield housing having a plasma display module inside, and composed of: a conductive filter part arranged on the observer's side of the plasma display panel; and a conductive housing part electrically connected to the conductive filter part. The conductive filter part has a good conductive portion being a belt-like portion in the same direction as that of the electrode, having conductivity better than that of other conductive portions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plasma display device known as a large-screen thin display device.

  2. Description of the Related Art Self-luminous display devices such as a plasma display device and a CRT display (Cathode-Ray Tube display) device are widely used because a natural image can be obtained without dependency on a viewing angle. In particular, plasma display devices are rapidly spreading because they are thin and optimal for constructing a large screen.

  The plasma display device is mainly composed of a plasma display module section having a plasma display panel and a shield casing surrounding the module.

  This plasma display panel is a display that generates visible light by exciting phosphors provided in each discharge cell by ultraviolet rays generated by gas discharge to generate display light, and includes a plurality of electrodes (display electrode pairs and address electrodes). ) Are arranged in a grid pattern, and an image is formed by selectively emitting light from discharge cells that intersect each electrode. Due to this principle, a large current for driving flows through the electrodes, and an electromagnetic field is generated by this current from the plasma display module.

  A shield case for shielding the generated electromagnetic field is, for example, a plasma display in which a front glass attached with a conductive filter and a conductive back cover on the back side are connected by a conductive member. The structure surrounding the module is used to electromagnetically shield the generated electromagnetic field.

  However, due to the increase in driving power accompanying the recent increase in image quality, it has become difficult to reliably reduce the electromagnetic field with the conventional shield housing configuration, particularly in the low frequency range of several tens of MHz or less. However, the conventional shield housing cannot sufficiently reduce these electromagnetic fields, and has a problem of radiating outside as noise.

  In response to such a problem, an adjacent conductor cylinder is provided on a ground return conductor plate that connects between a driving substrate provided on one end of the plasma display device and a driving substrate provided on the other end. There has been proposed a configuration in which the inductance of the ground return conductor plate is canceled by eddy current generated in the adjacent conductor cylinder (see, for example, Patent Document 1).

  There has also been proposed a plasma display device in which the shielding performance is improved by doubling the electromagnetic shield in the front cabinet portion that is held by sandwiching the peripheral portion of the front glass of the plasma display device together with the presser fitting (for example, , See Patent Document 2).

  There has also been proposed a plasma display device in which a closed current path between a drive source and a load circuit forms at least two loop-shaped paths, and cancels each other's magnetic field generated in each loop-shaped circuit (for example, (See Patent Document 3).

There has also been proposed a plasma display device in which a chassis conductor for holding a plasma display panel is connected to a back cover to surround and shield a drive circuit board (see, for example, Patent Document 4).
JP 2001-83909 A JP 2002-372917 A JP 2005-221797 A Japanese Patent Laid-Open No. 10-282896

  However, in the plasma display device described in Patent Document 1, if an adjacent conductor cylinder having a size that can be expected to be reduced is inserted between the panel and the ground return conductor plate, the entire loop area of the flowing current is increased and reduced. There is a problem that the electromagnetic field itself to be increased also increases the reduction effect.

  Moreover, in the plasma display device of Patent Document 2, the front cabinet is located only on the side surface portion of the entire device, and the effect of the double shield is limited to this portion. There is a problem that it is not sufficient in terms of the effect of reducing the field.

  Further, in the plasma display device of Patent Document 3, since the drive current path itself is extended, it is necessary to adjust the drive signal waveform and the like, and the electromagnetic field generated in the two loop shapes is completely canceled out. There is a problem that it is difficult to obtain a sufficient reduction effect.

  Further, in the plasma display device of Patent Document 4, although the shield effect is increased in the drive circuit board itself, there is a problem that the electromagnetic field generated by the current flowing between the plasma display panel and the chassis conductor cannot be sufficiently reduced. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a plasma display device that can reduce electromagnetic interference caused by a drive current flowing through a plasma display panel.

  The above object can be achieved by the following plasma display device. A plasma display apparatus for achieving the object includes a plasma display panel having a plurality of parallel electrodes, a circuit board for applying a voltage to the electrodes, the plasma display panel, and a ground of the circuit board. Connected, an end parallel to the direction of the electrode is electrically connected to the conductive casing, and an end perpendicular to the direction of the electrode includes a chassis conductor insulated from the conductive casing. A plasma display module is provided. Further, a shield housing including the plasma display module and comprising a conductive filter portion disposed on an observer side of the plasma display panel, and a conductive housing portion electrically connected to the conductive filter portion. With body. Furthermore, the conductive filter part is a plasma display device having a good conductive part which is a band-like part in the same direction as the direction of the electrode and has a better conductivity than other conductive parts.

  According to the plasma display device of the present invention, it is possible to provide a plasma display device that can efficiently reduce electromagnetic interference caused by the drive current flowing through the plasma display panel.

  Hereinafter, embodiments of a plasma display device and the like will be described with reference to the drawings. In the embodiment, components that perform the same operation may be denoted by the same reference numerals and the description thereof may be omitted.

(Embodiment 1)
1 to 4 show a plasma display device according to Embodiment 1, and FIG. 1 (a) is a front view for explaining the configuration of the plasma display device according to Embodiment 1 of the present invention. FIG. 1B is a schematic cross-sectional view taken along line aa in FIG. 1A, and shows only a structure deeply related to unnecessary electromagnetic radiation as an embodiment. FIG. 2 is a perspective view for explaining the configuration of the plasma display module in the plasma display device according to the first embodiment, and FIG. 3A shows the electrode structure of the plasma display panel in the plasma display device according to the first embodiment. 3B is a sectional view thereof, and FIG. 4 is a perspective view for explaining the structure of the conductive front filter in the plasma display device of the first embodiment.

  Hereinafter, for convenience of explanation, the normal direction of the display surface of the plasma display device 1 is the x axis, the longitudinal direction of the display surface of the plasma display device 1 is the y axis, and the direction orthogonal to the x axis and the y axis is the z axis. Sometimes called.

  1 and 2, the plasma display module 2 in the plasma display device 1 according to the first exemplary embodiment of the present invention includes plasma having scan / sustain electrodes 14 parallel to the longitudinal direction and address electrodes 15 parallel to the lateral direction. On the non-display surface side of the display panel 10, a chassis conductor 11 that is a holding plate of the plasma display panel 10 is disposed via a heat conductive sheet (not shown).

  The scan / sustain electrode drive circuit board 12 a, the address electrode drive circuit board 12 b, the relay circuit board 12 c, and the discharge control circuit board 12 d are arranged on the back side of the chassis conductor 11. In the scan / sustain electrode 14, the drive signal generated from the scan / sustain electrode drive circuit board 12 a is transmitted to the scan / sustain electrode 14 of the plasma display panel 10 through the flexible cable 13 a, and in the address electrode 15, the discharge control circuit board. The high-frequency signal generated in 12d is transmitted to the relay circuit board 12c by the flexible cable 13d, transmitted to the address electrode drive circuit board 12b by the flexible cable 13c, and a drive signal is generated in the address electrode drive circuit board 12b. The flexible cable 13b is transmitted to the address electrode 15 of the plasma display panel 10.

  On the outside of the plasma display module 2, a back casing 16, a glass pressing metal 17, a front glass 18, a front cabinet 19, a conductive front filter 20, and a conductive gasket 21 constitute a shield casing.

  As shown in FIG. 3, the plasma display panel 10 has a structure in which a front glass plate 101 and a rear glass plate 102 are bonded together, and a dielectric layer 103 is formed on the front glass plate 101 to form a scanning electrode 14a. And a plurality of scanning / sustaining electrodes 14 including the sustaining electrodes 14 b are formed so as to be protected by the dielectric layer 103. A dielectric layer 103 is also formed on the rear glass plate 102, and a large number are formed so that the address electrodes 15 are protected.

  A portion sandwiched between the scan / sustain electrode 14 and the address electrode 15 at the intersection of the scan / sustain electrode 14 and the address electrode 15 is a discharge cell 104, which is helium (He), neon (Ne), xenon (Xe). A discharge gas containing a rare gas such as) is enclosed. The discharge cell 104 is formed by being partitioned by a partition wall 105, and each of the discharge cells is coated with red, blue, and green phosphors 106a to 106c.

  The chassis conductor 11 is made of a metal plate such as aluminum or copper having high thermal conductivity and high electrical conductivity. The plasma display panel 10 is attached to one surface (front surface) via a heat conductive sheet, and the other surface. On the (rear) side, each drive circuit board or the like is attached in parallel with the chassis conductor 11 and connected to the ground of each board. For this reason, the chassis conductor 11 not only functions as a strength member that holds the plasma display panel 10 and each drive circuit board and maintains the strength thereof, but also functions as an electrical ground for each drive circuit board and the like. For example, the signal ground of the scan / sustain electrode drive circuit board 12a is point A, the signal ground of the address electrode drive circuit board 12b is point B, the signal ground of the relay circuit board 12c is point C, and the discharge control circuit board. The signal ground 12d is point D and grounded to the chassis conductor 11 which is a frame ground.

  As shown in FIG. 4, the conductive front filter 20 is formed on a base layer 201 made of a polyester film, a metal mesh such as copper or sputtered conductive layer 202 on the base layer 201, and a peripheral portion of the conductive layer 202. And a protective film 204 formed on the conductive layer 202 with a transparent insulating resin. Since the metal end portion 203 is not covered with the protective film 204, it functions as an electrical connection location.

  As the conductive layer 202, a copper mesh is used as a metal mesh, and a silver sputter is used as a sputter. Since the metal mesh has a lower resistivity, a high shielding effect can be obtained.

  The good conductive portion 205 is formed in a strip shape at a substantially central portion of the conductive layer 202. The good conductive portion 205 has higher conductivity than other portions of the conductive layer 202. For example, the good conductive portion 205 can be formed by overlaying transparent ITO or the like on the conductive layer 202.

  The front glass 18 is disposed on the front surface side of the plasma display panel 10, and a conductive front filter 20 is attached to the back surface (the side opposite to the display surface).

  The glass retainer 17 is fixed by sandwiching the front glass 18 with the front cabinet 19 and is a conductive contact member with the metal end 203 of the conductive front filter 20 attached to the front glass 18. It arrange | positions so that it may contact electrically through the conductive gasket 21. FIG. Further, the back cover 16 is in contact with the conductive gasket 21.

  The conductive gasket has a configuration in which metal fibers are attached to the surface of an elastic material such as sponge. Although a conductive gasket is used as the conductive contact member here, the present invention is not limited to this. In other words, any material having electrical conductivity and ensuring the stability of electrical contact between the two members may be used. For example, a conductive spring portion may be formed on the glass pressing member 17. In this way, the cost can be reduced.

  The back cover 16 is formed by press-molding a conductive metal plate, and is fixed to the glass pressing metal 17 so as to cover the back surface of the plasma display panel 10 and each drive circuit board, etc. It plays a role of shielding electromagnetic waves radiated from each drive circuit board and the like. The back cover 16 forms a conductive casing portion together with the gasket 21 and the glass pressing metal 17.

  Here, in the plasma display device 1 according to the present embodiment, the principle and operation of reducing unnecessary radiation of electromagnetic interference waves due to the drive current will be described based on the operation principle of the plasma display panel.

  First, the image display principle of the plasma display panel 10 will be described. First, initialization discharge is performed in which a voltage is applied to all lines of the scan electrode 14a to cause discharge in all the discharge cells. Next, a voltage is sequentially applied to the scan electrode 14a, and a voltage is also applied to the address electrode 15 that intersects with a discharge cell desired to emit light on the scan electrode to which the voltage is applied. This is called address discharge, and a discharge cell at a position where the scan electrode 14a to which the voltage is applied intersects with the address electrode 15 emits light, and the discharge cell is selected as a light emitting cell. Thereafter, a sustain discharge is performed in which an AC voltage is applied between scan electrode 14a and sustain electrode 14b. Due to the sustain discharge, only the previously selected light emitting cell emits light, and the plasma display panel displays an image.

  Next, the principle and operation of reducing unnecessary radiation of electromagnetic interference waves due to the drive current will be described with reference to FIG. FIG. 5 is a diagram showing the principle that unnecessary radiation of electromagnetic interference waves due to panel drive current is reduced.

  In general, when a loop-shaped current 30 flows, a strong magnetic field 31 is generated in a direction perpendicular to the plane forming the loop according to Fleming's right-hand rule. When the ring-shaped conductor 32 is placed at a position including the loop current 30, a counter electromotive force is generated in the conductor due to the electromagnetic induction effect, and a current 33 in the direction opposite to the original loop current 30 is induced. Is done. This ring-shaped conductor 32 is called a short ring. Since the magnetic field 34 generated by the induced current 33 is generated in the opposite direction to the magnetic field 31 generated by the original loop current, there is an effect of canceling the original generated magnetic field 31.

  In the configuration of FIG. 1, the drive current driven from the scan / sustain electrode drive circuit board 12a flows through the flexible cable 13a, the scan / sustain electrode 14 of the plasma display panel 10 and the chassis conductor 11, and the loop drive current is generated. Generated.

  Further, the loop-shaped drive current generates a magnetic field in the vertical direction (the direction parallel to the z direction in FIG. 1) according to Fleming's right-hand rule.

  Here, the loop formed by the good conductive portion 205, the gasket 21, the glass retainer 17 and the back cover 16 is substantially parallel to the driving current loop during the sustain discharge in the plasma display module 2. Accordingly, a loop current in the direction opposite to the drive current is excited on the loop including the good conductive portion 205, the gasket 21, the glass pressing metal 17, and the back cover 16 so as to cancel the magnetic field.

  As a result, the shield case plays a role of a short ring against the AC magnetic field created by the loop of the drive current during the sustain discharge that is formed during the sustain discharge in which a large current flows. A large noise reduction effect can be obtained.

  In the present embodiment, the good conductive portion 205 is formed in the substantially central portion, but the present invention is not limited to this. For example, it is possible to form a plurality of positions that are biased to either the top or bottom. According to the principle shown in FIG. 5, the unnecessary radiation magnetic field due to the panel drive current is strongest at the center of the panel. Therefore, by disposing the good conductive portion 205 at the center, the unnecessary magnetic field canceling effect by the short ring is maximized.

  Next, a modification of the first embodiment will be described with reference to FIG. FIG. 6 is a perspective view for explaining the connection of the gasket 21.

  In the present modification, a good conductive gasket portion 22, which is a portion having a lower resistance value than the other portions, is used at a substantially central portion of the gasket 21. The good conductive gasket part 22 is provided corresponding to the position where the good conductive part 205 of the conductive front filter 20 is formed.

  With this configuration, the entire short ring to be formed can be formed with lower resistance, and the effect of canceling unnecessary magnetic fields can be further enhanced.

  The good conductive gasket part 22 can be formed by, for example, forming a material having a lower resistance value than other parts, or attaching a conductive tape such as a copper tape from above.

  In the present embodiment or the modification, the good conductive portion 205 is formed in the longitudinal direction of the display surface so as to cancel the drive current loop during the sustain discharge, but the present invention is not limited to this. For example, a current loop that flows in the short direction of the display surface (for example, the zx plane in FIG. 1) is formed during address discharge, so that the electromagnetic interference wave that accompanies address discharge can be formed by configuring the good conductive portion 205 accordingly. Can also be reduced.

  The specific numerical values and the like used in the above embodiments are merely examples, and can be appropriately set to optimal values according to the characteristics of the display device and the specifications of the image display device. is there.

  The above-described embodiment is an example of the present invention. The present invention is not limited to the above-described embodiments, and various modifications are possible, and it goes without saying that these are also included in the scope of the present invention.

  As described above, the plasma display device according to the present invention is useful as a plasma display device or the like that can effectively reduce electromagnetic interference generated by the current flowing through the plasma display panel.

(A) Front schematic diagram for explaining the configuration of the plasma display device according to the present invention, (b) Schematic cross-sectional view taken along line aa in FIG. The perspective view for demonstrating the structure of a plasma display module (A) The perspective view for demonstrating the electrode structure of the plasma display panel in the plasma display apparatus which concerns on Embodiment 1, (b) In order to demonstrate the electrode structure of the plasma display panel in the plasma display apparatus which concerns on Embodiment 1. FIG. Cross section of The perspective view for demonstrating the structure of the electroconductive front filter which concerns on this invention Explanatory diagram showing the principle of reducing unnecessary radiation of electromagnetic interference due to panel drive current The perspective view for demonstrating the connection of the gasket in the modification of the plasma display apparatus which concerns on Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma display apparatus 2 Plasma display module 10 Plasma display panel 11 Chassis conductor 12a Scan / sustain electrode drive circuit board 12b Address electrode drive circuit board 12c Relay circuit board 12d Discharge control circuit board 13a, 13b, 13c, 13d Flexible cable 14 Scan / sustain electrode 15 Address electrode 16 Back cover 17 Glass retainer 18 Front glass 19 Front cabinet 20 Conductive front filter 21 Conductive gasket 22 Good conductive gasket part 30 Loop current 31 Magnetic field generated by loop current 32 Ring-shaped conductor 33 Induced current 34 Magnetic field generated by induced current 101 Front glass plate 102 Rear glass plate 103 Dielectric layer 104 Discharge cell 105 Partition 106a, 106b, 106c Body 201 base layer 202 conductive layer 203 metal end 204 protective film 205 Yoshirubeden unit

Claims (5)

A plasma display panel having a plurality of parallel electrodes, a circuit board for applying a voltage to the electrodes, and an edge that holds the plasma display panel and is connected to the ground of the circuit board and is parallel to the direction of the electrodes Is electrically connected to the conductive casing, and a plasma display module having a chassis conductor insulated from the conductive casing with an end perpendicular to the direction of the electrodes;
A shield housing that includes the plasma display module and includes a conductive filter portion disposed on an observer side of the plasma display panel; and a conductive housing portion electrically connected to the conductive filter portion; With
The conductive filter portion is
A plasma display device having a good conductive portion which is a band-like portion in the same direction as the direction of the electrode and has better conductivity than other conductive portions. The plasma display apparatus according to claim 1, wherein the electrode is an electrode for scanning and maintaining discharge. The plasma display device according to claim 1, wherein the good conductive portion is located at a substantially central portion of the conductive filter portion. The plasma display device according to claim 1, wherein the good conductive portion is made of a transparent conductor. The conductive filter portion is connected to the conductive casing portion by a conductive contact member, and a contact portion between the good conductive portion and the conductive casing portion is in contact with the conductive filter portion other than the good conductive portion. The plasma display device according to claim 1, wherein a conductive contact member having a resistance value lower than that of the portion is used.