Plasma display device

A plasma display device that includes a plasma display panel adapted to display images on a front side thereof, a chassis base including conductive material and arranged behind the plasma display panel, a plurality of circuit boards adapted to drive the plasma display panel, the plurality of circuit boards being fixed on the chassis base with a gap between each of the plurality of circuit boards and the chassis base and a driving circuit portion including a plurality of cables and adapted to electrically connect the circuit boards, wherein the chassis base includes at least one holding unit that is adapted to hold the plurality of cables on one side of the chassis base. The holding unit being adapted to attenuate EMI before it reaches the cables within.

CLAIM OF PRIORITY

This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for PLASMA DISPLAY DEVICE earlier filed in the Korean Intellectual Property Office on 17 Jan. 2007 and there duly assigned Serial No. 10-2007-0005433.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plasma display device, and more particularly, to a plasma display device including at least one holding unit attenuates the electromagnetic interference (EMI) generated in a driving circuit portion that drives a plasma display panel.

2. Description of the Related Art

In general, a plasma display device includes a plasma display panel that makes use of plasma generated as a result of gas discharge, a chassis base that supports the plasma display panel, and a driving circuit portion that is fixed on the chassis base and drives the plasma display panel. The plasma display panel includes two sheets of glass substrates facing each other, and the space internally formed between the glass substrates forms a discharge space having a plurality of electrodes. Each of the electrodes is applied with voltage that is supplied by the driving circuit portion, thereby displaying an image on the plasma display panel.

The chassis base is bonded to the plasma display panel by means of double-sided adhesive tape that is attached on the front side of the chassis base, while a plurality of circuit boards are fixed on the rear side of the chassis base. The circuit boards are usually fixed onto the chassis base by adjoining a bolt that passes through the binding holes formed in the circuit boards, to a boss installed on the chassis base. The chassis base is formed of a metallic material having a higher mechanical hardness than the plasma display panel, thus being capable of supporting the plasma display panel. The chassis base has excellent thermal conductivity, and thus plays a role of dissipating the heat generated by the plasma display panel. The chassis base is also formed of a material having good electric conductivity, and thus plays a role as a ground shield of EMI that is generated during the operation of the plasma display panel.

The driving circuit portion includes a plurality of circuit boards and a plurality of cables electrically connecting the circuit boards. Each of these circuit boards includes a plurality of driving circuit boards for controlling the electrodes formed on the plasma display panel, a buffer circuit board for intermediating the electrode drive of the driving circuit boards, a logic circuit board for generating control signals based on the image signals applied from an external source and transmitting the control signals to the driving circuit boards, and a power supply circuit board for supplying electric power to each of the circuit boards.

Among these, when a cable is installed alongside with a circuit board having high intensity signals, such as the power supply circuit board, the cable is vulnerably exposed to the EMI generated by the circuit board, and thus, there can be an occurrence of signal distortion or malfunction of the plasma display panel. Furthermore, if the cable is a power line, the EMI generated by the cable itself can affect the function of the circuit board, thereby causing a problem in product reliability of the plasma display device as a whole. What is needed is a design for a plasma display device that prevents EMI generated the plasma display device from disrupting the performance of other circuit elements located within the plasma display device.

SUMMARY OF THE INVENTION

It is an aim of the present invention to address the conventional problems of plasma display devices described above, and in particular, to provide a plasma display device that can attenuate or block EMI that is generated by a driving circuit portion and reduce signal distortion, by having at least one holding unit for holding cables that shields the cables from EMI produced elsewhere within the plasma display device, the cables electrically connecting circuit boards to other circuit boards disposed behind the plasma display panel.

According to an aspect of the present invention, there is provided a plasma display device that includes a plasma display panel adapted to display images on a front side thereof, a chassis base including conductive material and arranged behind the plasma display panel, a plurality of circuit boards adapted to drive the plasma display panel, the plurality of circuit boards being fixed on the chassis base with a gap between the plurality of circuit boards and the chassis base and a driving circuit portion including a plurality of cables adapted to electrically connect the circuit boards, wherein the chassis base includes at least one holding unit that is adapted to hold the plurality of cables on one side of the chassis base. The plasma display device can also include a heat sink sheet arranged between the plasma display panel and the chassis base.

The holding unit can include a tube protruding toward a direction where the circuit boards are fixed, and includes a pair of openings adapted to allow one of said plurality of cables to pass through. The holding unit can include a rectangular-shaped perpendicular cross-section. The holding unit can include two lateral sides, one of the two lateral sides being open. The holding unit can include a semicircular shaped perpendicular cross-section. The holding unit can include at least one fixing member adapted to fix the plurality of cables within. The fixing member can be bound to the holding unit on one end via a binding aperture arranged in the holding unit, the other end of the fixing member can include a nipper adapted to hold the cables together. The holding unit can be a trench arranged in a side of the chassis base facing the plasma display panel. The holding unit can be formed to penetrate the chassis base, and includes openings that respectively serve as an inlet and an outlet for the cables. The chassis base can be made out of either an aluminum (Al) alloy or an iron (Fe) alloy. Each of the plurality of circuit boards can be a board selected from the group consisting of a power supply circuit board, a driving circuit board, a logic circuit board and a buffer circuit board. The heat sink sheet can be made out of a material based on conductive carbon fiber. The holding unit and the chassis base can be integral with each other. The holding unit can be adapted to prevent electromagnetic interference (EMI) from the plurality of circuit boards from reaching the plurality of cables within the holding unit and can be adapted to prevent EMI generated by the plurality of cables within from reaching the plurality of circuit boards. The holding unit can be made out of an aluminum (Al) alloy or an iron (Fe) alloy.

DETAILED DESCRIPTION OF THE INVENTION

Turning now toFIGS. 1 through 3,FIG. 1is a perspective view schematically illustrating a plasma display device1according to the first embodiment of the present invention,FIG. 2is a diagram illustrating the holding unit holding cables, shown as the portion cut along the line A-A′ ofFIG. 1andFIG. 3is a view taken along B-B′ ofFIG. 1. Referring toFIGS. 1 through 3, the plasma display device1according to the first embodiment of the present invention includes a plasma display panel10that displays an image by means of gas discharge, a chassis base20that is disposed behind the plasma display panel10, a driving circuit portion30including a plurality of circuit boards31a,31b,31c,31d,31eand31f, that are fixed on the side of the chassis base20that is opposite to the side facing the plasma display panel10, with a gap separating the circuit boards from the chassis base20, and a plurality of cables32a,32b,32c,32d,32e,32f,32gand32h, electrically connecting the circuit boards31a,31b,31c,31d,31e,31f, and a plurality of holding units50a,50b,50c,50d,50e,50f,50gand50h, that are formed on one side of the chassis base20to hold at least a part of the cables32a,32b,32c,32d,32e,32f,32gand32h. The plasma display device1can be also formed to include a heat sink sheet60interposed between the plasma display panel10and the chassis base20.

Hereinafter, the plurality of circuit boards31a,31b,31c,31d,31eand31fwill be collectively referred to as circuit boards31. Furthermore, the plurality of cables32a,32b,32c,32d,32e,32fand32gwill be collectively referred to as cables32. Also, the plurality of holding units50a,50b,50c,50d,50e,50fand50gwill be collectively referred to holding unit50.

The plasma display panel10includes a front panel11and a rear panel12, and discharge cells (not shown in the figures) between the front panel11and the rear panel12, and the plasma display device10being attached on the front side of the chassis base20by means of an adhesive bonding material such as double-sided adhesive tape40or an equivalent. More particularly, the plasma display panel10includes discharge cells containing a discharge gas, a phosphor coated on the inner surfaces of the discharge cells and electrodes to which voltage are applied. The operation of the plasma display panel10as such is initiated by signals transmitted from the driving circuit portion30that is connected to the electrodes, the plasma display panel10subsequently generating plasma discharge, and ultraviolet radiation generated as a result of the plasma discharge exciting the phosphor to emit visible light, thereby producing a visible image.

The driving circuit portion30includes a plurality of circuit boards31including driving circuits, and a plurality of cables32electrically connecting the circuit boards31. These circuit boards31are fixed on the chassis base20on the side that is opposite to the side of the chassis base20facing the plasma display panel10. The plurality of circuit boards31can be specifically divided into a plurality of driving circuit boards31a,31band31ccontrolling the electrodes formed inside the plasma display panel10; a buffer circuit board31dmediating the electrode drive of a driving circuit boards31a,31band31c; a logic circuit board31egenerating control signals based on the image signals applied from an external source and transmitting the control signals to the driving circuit boards31a,31band31c; and a power supply circuit board31fsupplying the power to each of the circuit boards described above.

The cables32are connections between the circuit boards31, including power lines transmitting electric power and signal lines transmitting data related to the drive of the circuit boards, to each of the circuit boards31. These cables32can be formed to have various thicknesses depending on the type of the circuit board31to be connected. The cables32can also be in the form of a bundle of multiple strands, but the present invention is not limited thereto.

The chassis base20takes the role of fixing the circuit boards31while supporting the plasma display panel10, and the role of grounding EMI. Thus, the chassis base20can be formed of an aluminum (Al) alloy or an iron (Fe) alloy, that has good electric conductivity accompanied by high hardness. However, the material of the chassis base20that can be used for the present invention is not limited thereto, and the chassis base20can be formed of a variety of metal materials having both electric conductivity and hardness. The chassis base20is formed integrally with at least one holding unit50that can hold at least a part of the cables32.

The holding unit50is formed integrally with the chassis base20in the form of a tube protruding from the chassis base20toward the direction where the circuit boards31are fixed. The holding unit50is formed by a press processing method. The holding unit50is formed to have openings51that serve as an inlet and an outlet for the cables32, on both ends of the tube. The holding unit50can have a plurality of openings51at various locations, if necessary, with each opening having a circular or a rectangular shape. The openings51can be formed by punching after the holding unit50has been formed, or can be simultaneously formed together with the holding unit50during the press processing.

The holding unit50can be selectively formed along the paths of wiring of the cables32, and in this case, the perpendicular cross-section of a holding unit can be rectangular in shape. Such shape can have a relatively large volume within a limited space, and thus is advantageous in holding a large number of cables or relatively thick cables.

The heat sink sheet60serves to transfer heat generated in the plasma display panel10to the chassis base20, so that the heat can be dissipated out. The heat sink sheet60also helps in grounding the EMI generated by circuit boards mounted on the chassis base20, as at least a portion of the heat sink sheet60is connected to the chassis base20. The heat sink sheet60can be formed of a material based on conductive carbon fiber. However, the material of the heat sink sheet60that can be used for the present invention is not limited thereto, and the heat sink sheet60can be formed of a variety of materials having good electric conductivity and thermal conductivity.

According to the first embodiment of the present invention as described above, the chassis base20has at least one holding unit50that is integrally formed with the chassis base20and holds cables32, so that the appearance of the plasma display device1can be enhanced when the cables32are neatly held by the holding unit50. Furthermore, since the holding unit50is formed on the chassis base20along the predetermined paths of wiring of the cables32prior to the assembly of the driving circuit portion30, wiring of the cables32can be efficiently carried out. The cables32held in the holding unit50as described above are also protected by the holding unit50from being pressed by a pressing instrument during the process of assembling the plasma display device1, or from being damaged by an external factor.

The holding unit50is formed to envelop the cables32, and thus can effectively attenuate the EMI generated by the driving circuit portion30. The holding unit50holds the cables32such that the cables32transmitting electric signals are prevented from being affected by the EMI generated by the circuit boards31, that can cause signal distortion. Furthermore, the holding unit50also protects the driving circuit portion30in the vicinity of the cables32including power lines, by attenuating or blocking the EMI generated by the cables32themselves.

Since the plasma display device1optionally contains a heat sink sheet60, and in this case, the heat sink sheet60is formed of a material that can absorb EMI, the EMI generated by the cables32and emanating in a direction towards the plasma display panel10can be attenuated or blocked by the heat sink sheet60. This structure can attenuate EMI more effectively. The plasma display device1constructed as such can prevent the malfunction of the plasma display panel10due to the signal distortion caused by the EMI generated in the driving circuit portion30, and thus attain improved product reliability.

Next, a plasma display device according to a second embodiment of the present invention will be described in conjunction withFIG. 4.FIG. 4is a perpendicular cross-sectional view of a portion of a plasma display device according to the second embodiment of the present invention, illustrating the portion corresponding to the portion shown inFIG. 3focusing on a cross section of a holding unit. The plasma display device according to the second embodiment of the present invention is identical or similar to the plasma display device1according to the first embodiment as shown inFIGS. 1 through 3in most regards. Thus, the following description will be focused on the parts of the configuration of the second embodiment that are different from the corresponding parts in the first embodiment.

Referring toFIG. 4, in the plasma display device according to the second embodiment of the present invention, a holding unit150is formed in a rectangular shape in that any one of the two lateral sides of the perpendicular cross-section is open. Thus, the holding unit150can have a lateral-side opening152. The lateral-side opening152serves as an inlet as well as an outlet for the cables32. Accordingly, the trouble of forming openings at a number of sites can be eliminated, and there is an advantage that the holding unit150thus shaped helps in shortening the time required for the design and processing of the device. However, if necessary, it is also possible to form more openings on the side facing the lateral-side opening152in the holding unit150. In this case, the openings can be formed to have either a circular shape or a rectangular shape.

Next, a plasma display device according to a third embodiment of the present invention will be described in conjunction withFIG. 5.FIG. 5is a perpendicular cross-sectional view of a portion of a plasma display device according to the third embodiment of the present invention, illustrating the portion corresponding to the portion shown inFIG. 3focusing on a cross section of a holding unit. Since the plasma display device according to the third embodiment of the present invention is identical or similar to the plasma display device according to the first embodiment as shown inFIGS. 1 through 3in most regards, the following description will be focused on the parts of the configuration that are different from the corresponding parts in the first embodiment.

Referring toFIG. 5, in the plasma display device according to the third embodiment of the present invention, a holding unit250is formed to have a semicircular-shaped perpendicular cross-section. The holding unit250is formed to have a relatively lower height of the protrusion toward the direction of the circuit boards than that ofFIGS. 3 and 4, making the process of installing circuit boards much easier. The holding unit250has a smaller volume compared with the rectangular-shaped holding unit50of the first embodiment of the present invention, and accordingly, it is advantageous in the case of holding relatively thinner cables. Furthermore, since the holding unit250is formed in a circular shape corresponding to the shape of a cable, the holding unit250can more efficiently attenuate the EMI generated in the driving circuit portion30.

Next, a plasma display device according to a fourth embodiment of the present invention will be described.FIG. 6is a cross-sectional view of a portion of a plasma display device according to the fourth embodiment of the present invention, depicting the form of the holding unit holding cables. Since the plasma display device according to the fourth embodiment of the present invention is identical or similar to the plasma display device according to the first embodiment as shown inFIGS. 1 through 3in most regards, the following description will be focused on the parts of the configuration that are different from the corresponding parts in the first embodiment. Meanwhile, the fourth embodiment of the present invention is also applicable to the second or third embodiments described above.

Referring toFIG. 6, in the plasma display device according to the fourth embodiment of the present invention, a holding unit350includes a number of separate fixing members70to fix the cables32within. The fixing member70is bound to the holding unit350at one end via a binding hole352formed in the holding unit350, while having the other end in the form of a nipper to hold cables together. The fixing member70can instead be formed into a simple ring shape, instead of the nipper form, to hold cables together. However, the form of the fixing member70that can be used for the present invention is not limited thereto, and the fixing member70can be formed into a variety of shapes that can hold cables together. One or more fixing members70can be installed within a holding unit350to serve to prevent cables from breaking away from the holding unit350. The holding unit350includes openings351that serve as an inlet and an outlet for the cables32. According to the current embodiment of the present invention, the chassis base320and the holding unit350are formed integrally and cannot be separated from each other. Thus, when the cables32are held in the holding unit350, the holding unit350can absorb the EMI generated by the cables32, or prevent the cables32from being exposed to the EMI generated by the circuit boards31. Thus, the amount of generated EMI that reaches another circuit component within the display device is reduced, and the product reliability of the plasma display device is improved.

Next, a plasma display device according to a fifth embodiment of the present invention will now be described in conjunction withFIG. 7.FIG. 7is a cross-sectional view of a portion of a plasma display device according to the fifth embodiment of the present invention, depicting the form of the holding unit holding cables. The plasma display device according to the fifth embodiment of the present invention is identical or similar to the plasma display device according to the first embodiment as shown inFIGS. 1 through 3in most regards. Thus, the following description will be focused on the parts of the configuration that are different from the corresponding parts in the first embodiment.

Referring toFIG. 7, in the plasma display device according to the fifth embodiment of the present invention, a holding unit450is formed such that the side of the chassis base420facing the circuit boards31is flat, while the other side of the chassis base420facing the plasma display panel10is formed in the shape of a trench to hold the cables32. The holding unit450can be formed by a press processing method. The holding unit450has openings451that are formed to penetrate vertically through the chassis base420at the two lateral edges or at any site where required. The openings451can be formed to have a circular or rectangular shaped cross-section. The cables32are held to be interposed between the trench-shaped holding unit450and the heat sink sheet60, and enter the holding unit450through the openings451. Since the holding unit450is flat in shape, it is preferable for such holding unit to hold cables that are wide and flat in shape, or cables that are thinner than the thickness of the chassis base420. The holding unit450also reduces the amount of EMI generated in the driving circuit portion30that receives the cables on the basis of the same principle applied in other embodiments of the present invention. The chassis base420is formed to have a flat rear side while still including the holding unit450, and is advantageous in that circuit boards can be relatively efficiently installed.

As described above, the present invention has been described with reference to the specific preferred embodiments described above, but the present invention is not intended to be limited thereto. Rather, it should be understood that various modifications and variations of the present invention can be made by those skilled in the art without departing from the spirit and the technical scope of the present invention as defined by the appended claims.

As described above, the plasma display device according to the present invention is useful in achieving efficient wiring by holding cables in at least one holding unit that is formed integrally with the chassis base, and has an effect of enhancing the appearance of the plasma display device. Furthermore, the holding unit according to the present invention attenuates the EMI generated by circuit boards from affecting the electric signals transmitted by the cables, or absorbs the EMI generated by the cables themselves, thereby reducing the overall EMI generated in the driving circuit portion and improving the reliability of the plasma display device. In addition, the holding unit according to the present invention has an effect of protecting the cables from being damaged during the process of assembling the plasma display device.