KR100670497B1 - Plasma Display Device - Google Patents

Abstract

The present invention relates to a plasma display device capable of generating noise and suppressing radiation.

A plasma display device according to the present invention includes a plasma display panel, a plurality of printed circuit boards for supplying a driving signal to the plasma display panel, a connecting member for connecting each of the printed circuit boards, and a connecting member from the printed circuit board. And a filter member disposed on the connecting member so that the connecting member penetrates to block the electromagnetic wave transmitted through the electromagnetic wave, and the electromagnetic wave transmitted from the printed circuit board to the connecting member near the connecting portion of the connecting member and the printed circuit board. A plurality of filter elements are formed for filtering.

Ferrite Cores, Low Pass Filters, Electromagnetic Waves

Description

Plasma Display Device

1 is a view showing a plasma display device of the present invention.

Figure 2 is a simplified view showing a form in which a printed circuit board is connected by a connecting member having a filter member of the present invention.

3 is a more detailed view of the filter circuit of FIG.

4 shows an example of a drive waveform for driving a PDP.

<Explanation of symbols for the main parts of the drawings>

2: case 4: panel

6: heat conductive sheet 8: adhesive member

10: frame 12, 22, 32: printed circuit board

14, 24: connecting member 15, 25: filter member

27: filter circuit 28: link

29 pad 30 filter element

31: ground power

The present invention relates to a plasma display device, and more particularly, to a plasma display device capable of generating noise and suppressing radiation.

Recently, many flat display devices have been developed to replace cathode ray tubes (CRTs). Representative examples of such flat panel displays include liquid crystal displays (LCDs), electroluminescence displays (ELDs), field emission displays (FEDs), and plasma displays. A panel (or plasma display device, hereinafter referred to as " PDP ").

In particular, PDP has the advantage that it is easier to manufacture a large screen size than other flat panel display devices, and that complete digital processing is possible. Such a PDP implements an image by discharge. To this end, the PDP includes a printed circuit board for supplying a driving signal to the panel and the panel in which discharge is generated, and a thermal conductive sheet and a frame inserted between the panel and the printed circuit board. Since this PDP processes an image by discharge, a high potential signal for generation of discharge is used. The printed circuit board is designed with a high withstand voltage rating for the signal voltage so that the processing of such a high potential signal can be performed stably. Such a printed circuit board plays a role of generating various driving signals when the PDP is driven, and is usually composed of several pieces of printed circuit boards classified by functions.

Each of these printed circuit boards is divided into a data driver, a scan driver, a sustain driver, a control circuit and a power supply. Each of these is connected to each other by conductive connection means such as a flexible printed circuit (FPC).

On the other hand, the PDP generates a lot of electromagnetic interference (EMI) by the operation of the driving signal and the circuit element generated during the driving. This is because the characteristics of the PDP are generated in the form of the driving signal repeating on and off, and at this time, the signal voltage between the on-time and off-time (Off_Time) has a difference of several tens to several hundred volts [V] or more. However, a sudden change in signal voltage causes a lot of EMI. Such EMI has a bad effect on the user and is a factor that hinders the normal operation of the driving unit formed on the printed circuit board. In particular, EMI generated from one substrate causes electromagnetic interference not only to the substrate but also to other adjacent substrates, causing PDP malfunction such as signal distortion and attenuation. The main factor that affects adjacent substrates due to EMI generated in one substrate is that each substrate is connected to each other by a conductive path. That is, the EMI generated from one substrate is transferred to adjacent substrates along the conductive path, and the emissivity of the EMI increases due to the increase of the EMI propagation path connecting the conductive path and the substrate. In addition, when the frame located below the printed circuit board is a plastic resin-based material that does not absorb EMI, high frequency components included in the EMI cannot be absorbed and reflected or coupled to each other to increase the occurrence of failures caused by EMI. There is a problem.

Accordingly, an object of the present invention is to provide a plasma display device capable of generating noise and suppressing radiation.

Plasma display device according to the present invention for the above-mentioned object is a plasma display panel, a plurality of printed circuit boards for supplying a drive signal to the plasma display panel, a connecting member for connecting each of the printed circuit boards, the printed circuit A filter member disposed on the connecting member so that the connecting member penetrates to block electromagnetic waves transmitted from the substrate via the connecting member, and is connected from the printed circuit board near the connecting portion of the connecting member and the printed circuit board. A plurality of filter elements are formed for filtering the electromagnetic waves transmitted to the member.

This connecting member may be an FPC or a flexible flat cable.

In addition, the filter member may be a ferrite core.

In addition, the printed circuit board is formed with a plurality of pads and links for connection with the connection member, the filter element may be formed on each of the pad or link. The filter element may include a resistor and a capacitor.

In addition, the filter member may use any one of a cylindrical shape, a clip type, a plate type, and a tape type.

Other operations and features of the present invention in addition to the above object will be revealed through a detailed description of the embodiments with reference to the accompanying drawings. Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4.

1 is a view showing a plasma display device of the present invention.

Referring to FIG. 1, a plasma display device according to the present invention includes a case 2, a panel 4, a heat conductive sheet 6, an adhesive member 8, a frame 10, a printed circuit board 12, and a connection member ( 14).

The case 2 is composed of a front case 2a and a rear case 2b. The front case 2a is fastened to the rear case 2b to accommodate the panel 4, the heat conductive sheet 6, the adhesive member 8, the frame 10 and the printed circuit board 12 therein, and Protects internal enclosures from shocks and contaminants. In addition, the front case 2 is formed with a light transmitting portion 16 to emit visible light generated from the panel 4, and prevents the noise generated when the PDP is driven to the user.

The rear case 2b is fastened to the front case 2a to protect the contents of the interior and prevents the noise inside from leaking to the outside. In addition, the rear case 14 has a plurality of discharge ports for dissipating heat generated when the PDP is driven to the outside.

The panel 4 displays an image by the discharge generated by the drive signal. To this end, the panel 4 is provided with a front substrate 4a and a rear substrate 4b, and a plurality of electrodes, phosphors, dielectric layers, protective layers and barrier ribs formed between the front substrate 4a and the rear substrate 4b. do. The panel 4 is a printed circuit board (PCB) by a connecting member such as a tape carrier package (hereinafter referred to as "TCP") in the form of a chip-on-film (Chip On Film) in which an FPC and some driving chips are mounted. 12) is connected to the drive unit. In addition, an accessory member such as an adhesive member 8 and a thermally conductive sheet 6 may be attached to the rear surface of the panel 4.

The thermal conductive sheet 6 is inserted between the panel 4 and the frame 10 to transfer heat generated from the panel 4 to the frame 10 when the PDP is driven, or to radiate heat, thereby rapidly increasing the temperature of the panel 4. Prevent ascension. In addition, the thermally conductive sheet 6 evens the temperature distribution of the non-uniform panel 4, thereby preventing the panel 4 from being broken or malfunctioning due to local temperature differences. It is preferable that the heat conducting sheet 6 is different from the attaching method and role of the frame 10 according to the material for the normal operation of the PDP. For example, when the material of the frame 10 is a material having good thermal conductivity and heat dissipation, such as a metal frame, the thermal conductive sheet 6 is in close contact with the frame 10. In this case, a considerable amount of heat generated by the panel 4 is transferred to the frame 10 by the heat conductive sheet 6 to radiate heat, and part of the heat is radiated by the heat conductive sheet 6. On the other hand, when the material of the frame 10 is not good thermal conductivity and heat dissipation characteristics, such as a plastic frame, the thermal conductive sheet 6 and the frame 10 is provided to have a predetermined interval. At this time, most of the heat generated in the panel 4 is radiated by the heat conductive sheet 6, so that the temperature of the panel 4 can be kept constant.

The adhesive member 8 fixes the thermal conductive sheet 6 or panel 4 to the frame 10. To this end, the adhesive member 8 is formed in the form of a strip or frame in the edge portion of the thermal conductive sheet 6, as shown in Figure 1, to fix the thermal conductive sheet 6 or panel 4 to the frame 10 do. As such an adhesive member 8, it is possible to use an adhesive, an adhesive sheet and an adhesive tape. The adhesive member 8 may vary the thickness and shape of the attachment method and the adhesive member 8 according to the characteristics of the frame 10. As described above, in the case of using a frame made of a material having poor thermal conductivity and heat dissipation characteristics, it is preferable to provide a space between the adhesive members 8. The reason why the adhesive members 8 are spaced apart at predetermined intervals is to facilitate heat dissipation of the heat conductive sheet 6 by allowing air to flow through the space between the adhesive members 8. In addition, even when the adhesive member 8 directly attaches the panel 4 to the frame, it is preferable that the thickness of the adhesive member 8 is thickened to form a gap in which air can be distributed to dissipate the heat conductive sheet 6. Do. On the other hand, when using a frame made of a material having good thermal conductivity and heat dissipation characteristics, it is necessary to determine the shape and shape of the adhesive member 8 so that the thermal conductive sheet 4 and the frame are in close contact with each other.

The frame 10 fixes the panel 4 or the thermal conductive sheet 6 by the adhesive member 8. In addition, depending on the material of the frame 10, it is also possible to dissipate heat of the panel 4, the printed circuit board 12, and the TCP. The frame 10 supports and fixes the printed circuit board 12 by fastening means such as a boss or a screw. As described above, the frame 10 determines whether the frame 10 is in close contact with the thermal conductive sheet 6. In addition, when using the metal frame 10, it may be used as a ground power source of some of the driving circuit formed on the printed circuit board 12. In addition, a fixing ear portion for fixing the front case 2 or the rear case 14 may be formed at the edge or the edge of the frame 10.

The printed circuit board 12 includes a plurality of circuit parts for driving the PDP. The circuit portion is provided with a power supply for power supply, an address driver for supplying a drive signal to the electrodes of the panel 4, a scan driver and a sustain driver. Here, the printed circuit board 12 is divided into a plurality of printed circuit boards in which each driving unit is integrated or separated for each function. That is, the plurality of printed circuit boards 12 may include a power supply substrate on which a power supply is formed, an address driver substrate on which an address driver is formed, a scan / sustain driver substrate on which a scan driver and a sustain population are formed, and a control signal supplied to each driver. A control circuit part substrate is produced. Each printed circuit board 12 is connected to each other by a connection member 14 such as an FPC or an FFC to exchange power or signals. The filter circuit 17 for the filter having a predetermined capacitance is formed in the portion where the printed circuit boards 12 and the connection member 14 are connected to attenuate EMI generated from the printed circuit board 12 or Will be filtered. Further, drive signals from each drive unit are provided to the panel 4 via a drive buffer board provided between each drive unit substrate and the panel. Here, the scan driver and the sustain driver may be formed on the same substrate, and in this case, one buffer board may be shared. In addition, the driving buffer boards are connected to the panel 4 by connecting members 14 such as TCP and FPC.

The connection member 14 electrically connects each printed circuit board 12 for distribution of signals and power between each board. In addition, the connection member 14 includes a filter member 15 such as a ferrite core to filter the electromagnetic waves conducted by the connection member 14 when each printed circuit board 12 is connected. To this end, FFC, FPC and other cable members are used as the connecting member 14, and the filter member 15 is provided near the receiving side substrate of the signal or power when the printed circuit board 12 is connected.

The filter member 15 prevents the propagation of electromagnetic waves from the printed circuit board 12 on one side to the other printed circuit board 12 connected by the connection member 14, thereby ensuring the normal operation of the PDP. To this end, the filter member 15 is provided near the receiving side printed circuit board 12 of the connection member 14. As the filter member 15, it is preferable to use a ferrite core having excellent electromagnetic wave attenuation and filtering characteristics. Here, the ferrite core is used in the form of winding through or connecting the connecting member 14 to the tubular ferrite core. That is, when the connecting member 14 through which the signal passes passes through the ferrite core, the high frequency noise component is filtered using the magnetic attenuation effect peculiar to the ferrite.

2 is a view briefly showing a form in which a printed circuit board is connected by a connection member including a filter member of the present invention.

As shown in FIG. 2, the connection member 24 electrically connects the printed circuit boards 22. The connection member 24 is used in the form of a cable in which a plurality of circuit lines are provided in an integrated form. Each connecting member 24 is connected to pads formed at the signal line end of the printed circuit board 22 by soldering or the like. When the printed circuit board 22 is connected to both ends of the connection member 24 in this way, the filter member 25 is installed on one side of the connection member 24. This allows the connecting member 24 to penetrate the inside of the filter member 25 before connecting both ends of the connecting member 24 to the printed circuit board 22, and then connects the connecting member 24 to the printed circuit board 22. ) To install. At this time, when the signal direction of the connection member 24 is determined in one direction, the filter member 25 is installed to be located at a portion adjacent to the receiving side printed circuit board 22a of the signal. The filter member 25 may be provided in a form in which the connecting member 24 is wound one or more times, but since this may also cause attenuation of a normal signal, the number of windings should be appropriately adjusted.

The filter member 25 may be used in various forms such as cylindrical (or donut), plate type, clip type, and tape type that are frequently used in ferrite cores. Here, the plate-type filter member may be provided in a form of using two or more plate-shaped filter member is stacked, in the case of the clip type, one side is opened to surround the filter member, that is, a form such as 'c' may be used. In addition, the tape type may be used in the form of attaching the filter member 25 provided in the form of a thin sheet to the connecting member by an adhesive means such as an adhesive.

By using the connection member 24 having the filter member 25 as described above, electromagnetic waves generated in one side of the printed circuit board 12 and 22 and propagated through the connection members 14 and 24 are provided in the connection member 24. It is attenuated by the filtered filter member 25 and filtered. As a result, the occurrence of malfunction of the adjacent printed circuit boards 12 and 22 due to the conducted electromagnetic waves is reduced. In addition, the electromagnetic radiation paths generated by the printed circuit boards 12 and 22 and the connection members 14 and 24 and the adjacent printed circuit boards 12 and 22 that generate electromagnetic waves are generated by the filter members 15 and 25. It is possible to reduce EMI radiated outside the user or PDP.

3 is a diagram illustrating the filter circuit of FIG. 2 in more detail.

Referring to FIG. 3, a plurality of pads 29 and links 28 are formed on the printed circuit board 22 for connection with the connection members 14 and 24. The links 28 connect the pads 29 with the driving circuits not shown, and the individual pads 29 are connected with respective wires of the connecting members 14 and 24. The wires of the connecting members 14 and 24 are attached on the pad 29 by a method such as soldering. Filter elements 30 are formed at one side of the pads 29 to be electrically connected to the pads 29. The filter elements 30 include a capacitor 30a having a predetermined capacitance and a resistor 30b having a predetermined resistance value in order to attenuate and filter the electromagnetic waves generated in the driving circuit of the printed circuit board 22. Low-pass filter is implemented by using In addition, one side of the capacitor 30a is connected to the pad 29 and one side is connected to the ground power source 31 to implement the filter circuit 27.

This filter circuit 27 is also preferably formed on the transmission side printed circuit board 22 in consideration of signal attenuation and EMI propagation. The capacity of the capacitor 30a used in such a filter element is preferably determined within the range of approximately 10pF to 50pF in consideration of signal attenuation, electromagnetic wave filtering performance, and manufacturing cost in the case of PDPs currently commercialized. It is preferable to use a capacitor (30a) having a capacity of about 15pF or 30pF used as a standard product.

As described above with reference to FIGS. 2 and 3, the present invention provides a filter member provided in the low pass filter and the connecting members 14 and 24 at a connection portion with the connecting members 14 and 24 formed in the transmission side printed circuit board 22. And (15, 25). This prevents electromagnetic waves generated from one printed circuit board 12 and 22 from propagating through the connection members 14 and 24 and neighboring printed circuit boards 12 and 22, and radiates electromagnetic waves to the outside of the PDP. It is possible to shorten the path.

4 is a diagram showing an example of a driving waveform for driving a PDP, and is a diagram for explaining generation of electromagnetic waves during driving.

Referring to FIG. 4, the PDP includes a reset period RP for initializing the discharge cells of the full screen, an address period AP for selecting a cell, a sustain period SP for maintaining the discharge of the selected discharge cells, and An erasing period (EP) for erasing wall charges in the discharge cell.

In the setup period SU of the reset period RP in which the subfield SFn starts, the positive ramp waveform PR is applied to all the scan electrodes Y1 to Ym, and the sustain electrodes Z and the address electrodes are applied. 0 (V) is applied to (X). Due to the positive ramp waveform PR of the setup period SU, the voltage on the scan electrodes Y1 to Ym gradually rises from the positive sustain voltage Vs to a higher reset voltage Vr. The positive ramp waveform PR generates dark discharge in which almost no light is generated between the scan electrodes Y1 to Ym and the address electrodes X1 to Xn in the cells of the full screen. Dark discharge occurs between the scan electrodes Y1 to Ym and the sustain electrodes Z1 to Zm. As a result of this dark discharge, positive wall charges remain on the address electrodes X1 to Xn and the sustain electrodes Z1 to Zm immediately after the setup period SU, and the scan electrodes Y1 to Ym. Negative wall charges remain on the phase.

Following the set-up period SU, in the set-down period SD of the reset period RP, the negative ramp waveform NR in which the voltage gradually decreases from the positive sustain voltage Vs to the negative erase voltage Ve is It is applied to the scan electrodes Y1 to Ym. At the same time, a positive sustain voltage Vs is applied to the sustain electrodes Z1 to Zm, and 0 [V] is applied to the address electrodes X1 to Xn. Due to the negative ramp waveform NR, dark discharge is generated between the scan electrodes Y1 to Ym and the address electrodes X1 to Xn in the discharge cells 30 on the full screen, and at the same time, the scan electrodes Y1 to Dark discharge occurs between Ym) and the sustain electrodes Z1 to Zm. As a result of the dark discharge in this set down period SD, the wall charge distribution in each of the discharge cells 30 is changed to the optimum condition of the address. At this time, the excess wall charges unnecessary for the address discharge are erased on the scan electrodes Y1 to Ym and the address electrodes X1 to Xn in each discharge cell 30, and a certain amount of wall charges remains. The wall charges on the sustain electrodes Z are inverted from the positive polarity to the negative polarity as the negative wall charges transferred from the scan electrodes Y accumulate.

In the address period AP, the negative scan pulses -SCNP are sequentially applied to the scan electrodes Y1 to Ym, and at the same time, the positive electrodes are applied to the address electrodes X1 to Xn in synchronization with the scan pulses -SCNP. The surname data pulse DP is applied. The voltage of the scan pulse (-SCNP) is the scan voltage Vsc which is lowered from the negative scan bias voltage Vyb to 0 [V] or close to the negative scan voltage -Vy. The voltage of the data pulse DP is the positive data voltage Va. During this address period (AP), the sustain electrodes Z1 to Zm are supplied with a positive sustain voltage Vs or a lower positive bias low voltage Vzb. In the on-cells to which the scan voltage Vsc and the data voltage Va are applied, an address discharge is generated between the scan electrodes Y1 to Ym and the address electrodes X1 to Xn.

In the sustain period SP, a sustain pulse SSUS of the positive sustain voltage Vs is alternately applied to the scan electrodes Y1 to Ym and the sustain electrodes Z1 to Zm. Then, sustain discharges are generated between the scan electrodes Y1 to Ym and the sustain electrodes Z1 to Zm at every sustain pulse SSUS in the on-cells selected by the address discharge. On the contrary, the off-cells do not discharge during the sustain period SP.

In the erase period EP of the subfield SFn, the erase ramp waveform ERR is applied to the sustain electrodes Z. 0 [V] is applied to the scan electrodes Y1 to Ym and the address electrodes X1 to Xn during this erasing period EP. The erase ramp waveform ERR is a ramp waveform whose voltage is gradually imagined from 0 [V] to a positive sustain voltage Vs. The erase discharge is generated between the scan electrodes Y1 to Ym and the sustain electrodes Z1 to Zm in the on-cell in which the sustain discharge has been caused by the erase ramp waveform ERR. By this erase discharge, wall charges in the on cells are erased.

The driving waveform of FIG. 4 is a signal generated by the driving circuit during one subfield period and supplied to the panel. As can be seen in FIG. 4, a large number of waveforms rapidly rising to high potential or falling to low potential appear in one subfield period. As is already known, when a sudden rise and fall of a signal voltage occurs, electromagnetic waves also increase. On the other hand, in the case of the data pulse DP or the sustain pulse SSUS, the period in which the pulse is applied is very short, several μs, and the potential to be secured is also important. However, when the sustain pulse SSUS and the data pulse DP are distorted by electromagnetic noise, no discharge occurs or discharge occurs at an undesired time point, thereby degrading the overall quality of the PDP. In the present invention, in order to suppress such interference and transmission of electromagnetic waves, a filter circuit is formed on the printed circuit boards 12 and 22 as described above, and the connection member is provided with a filter member.

As described above, the plasma display apparatus according to the present invention includes a filter circuit formed near the connection portion of the printed circuit board and the connection member and a filter member installed at the end of the connection member. Through this, the plasma display device of the present invention can reduce the electromagnetic wave emissivity to the outside of the plasma display device by blocking the transmission path of the electromagnetic wave propagated through the connection member and the printed circuit board. In addition, the plasma display device of the present invention can block the transmission of electromagnetic waves and attenuate the electromagnetic waves in two stages, thereby preventing neighboring driving circuits from malfunctioning due to electromagnetic interference.

Claims (7)

A plasma display panel; A plurality of printed circuit boards for supplying a driving signal to the plasma display panel; A connection member for connecting each of the printed circuit boards; And a filter member disposed around the connection member so that the connection member penetrates to block electromagnetic waves transmitted through the connection member from the printed circuit board. And a plurality of filter elements for filtering electromagnetic waves transmitted from the printed circuit board to the connection member in the vicinity of a connection portion between the connection member and the printed circuit board. The method of claim 1, The connection member is a plasma display device, characterized in that the flexible printed circuit (Flexible Printed Circuit) or a flexible flat cable (Flexible Flat Cable). The method of claim 1, The filter member is a plasma display device, characterized in that the ferrite core (Ferrite Core). The method of claim 1, The printed circuit board is formed with a plurality of pads and links for connecting to the connection member, the filter element characterized in that the filter element is formed on each of the pad or link. The method of claim 1, And the filter element is a low pass filter including at least one resistor and at least one capacitor. The method of claim 5, And the capacitor has a capacity of 100 picofarads (pF) or less. The method of claim 1, The filter member may be any one of a cylindrical type, a clip type, a plate type, and a tape type.

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