Plasma display device

A display device is provided including a display panel for displaying an image, the display panel having substrates and electrodes located between the substrates. The display device also includes a chassis base supporting the display panel and a plurality of printed circuit board assemblies mounted in the chassis base for driving the display panel. One of the printed circuit board assemblies is an address buffer board assembly driving an address electrode, the address buffer board assembly including a flexible printed circuit connected to the address electrode. The flexible printed circuit has a terminal surface corresponding to a width of a terminal drawn from the address buffer board assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 2006-0110480 filed on Nov. 9, 2006, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.

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 having an address buffer board assembly and a flexible printed circuit that are directly connected to each other.

2. Description of Related Art

Generally, a plasma display device includes a plasma display panel (PDP) for displaying an image created by exciting phosphors using vacuum ultraviolet (VUV) rays emitted from plasma generated by gas discharge. The PDP also includes a chassis base for supporting the plasma display panel, and a plurality of printed circuit board assemblies mounted on the chassis base.

The printed circuit board assemblies are provided to drive electrodes. More specifically, the printed circuit board assemblies include a sustain board assembly connected to and controlling a sustain electrode, a scan board assembly connected to and controlling a scan electrode, an address buffer board assembly connected to and controlling an address electrode. The printed circuit board assemblies also include an image process/control board assembly generating a control signal for driving the address electrode, and a control signal for driving the sustain and scan electrodes by receiving an external image signal and applying the control signals to the corresponding board assemblies, and an electric power source board assembly providing electric power for driving the board assemblies.

A flexible printed circuit connects the address buffer board assembly to the address electrode and includes a driver integrated circuit package such as a tape carrier package (TCP). The driver integrated circuit package is assembled by installing a driver integrated circuit generating an address pulse for the address electrode on the flexible printed circuit. The driver integrated circuit package is located on a longitudinal side of the plasma display panel, and is connected to the address buffer board assembly in a U-shape.

In a conventional plasma display device, the address buffer board assembly and the flexible printed circuit are connected to each other by a connector. For example, a female connector attached on a terminal of the address buffer board is engaged with a male connector attached on the terminal of the flexible printed circuit.

However, as plasma display devices become larger and have higher definition, problems may arise when using a connector to connect the address buffer board to the flexible printed circuit. More specifically, the number of connecting portions necessary for the connectors increases and high impedance is induced from the high output connecting portion of the connectors, thereby increasing electromagnetic interference (EMI).

Furthermore, in a conventional plasma display device as the connector is interposed between the address buffer board assembly and the flexible printed circuit, a connection defect may occur at the connecting portion between the address buffer board assembly and the flexible printed circuit. In addition, there is a need to provide a dust cover to prevent a short circuit caused by foreign objects from occurring.

SUMMARY OF THE INVENTION

A display device is provided including a display panel for displaying an image, the display panel having substrates and electrodes located between the substrates. The display device also includes a chassis base supporting the display panel and a plurality of printed circuit board assemblies mounted in the chassis base for driving the display panel. One of the printed circuit board assemblies is an address buffer board assembly driving an address electrode, the address buffer board assembly including a flexible printed circuit connected to the address electrode. The flexible printed circuit has a terminal surface corresponding to a width of a terminal drawn from the address buffer board assembly. The address buffer board assembly may be a rigid flexible buffer board.

The address buffer board assembly may also include a low output terminal transmitting a low output logic signal and a high output terminal having a terminal surface larger than the low output terminal portion. The terminal of the address buffer board assembly and a terminal of the flexible printed circuit may be stacked at different heights. One of the terminals of the address buffer board assembly may be a ground terminal.

The terminal of the flexible printed circuit may extend integrally with a terminal drawn from the address buffer board assembly and the flexible printed circuit may be a tape carrier package. An anisotropic conductive film may be interposed between the terminal of the flexible printed circuit and the terminal of the address electrode drawn out of a dielectric layer of the display panel to electrically connect the terminal of the flexible printed circuit and the terminal of the address electrode. The display device may be a plasma display device.

Also provided is a method of connecting a printed circuit board assembly of a display device as described above to a flexible printed circuit The method includes locating an electrode on the display panel, the electrode having an electrode terminal at one end, connecting a flexible printed circuit to the electrode such that a flexible printed circuit terminal extends integrally with a printed circuited board assembly terminal, and locating an anisotropic conductive film between the flexible printed circuit terminal and the electrode terminal to electrically connect the flexible printed circuit terminal to the electrode terminal.

DETAILED DESCRIPTION

As shown inFIGS. 1 and 2, a plasma display device of an embodiment of the present invention includes a PDP11for displaying an image using gas discharge, a heat dissipation sheet13, a chassis base15, and a plurality of printed circuit board assemblies17.

The plasma display panel11includes two glass substrates facing each other and spaced from each other to form a discharge space. Since the plasma display panel11has weak mechanical strength against external impact, the chassis base15may be formed from a material having higher mechanical strength than the glass substrates, such as a metal, to support the plasma display panel11. Additionally, the chassis base provides a space to hold the printed circuit board assemblies17, and functions as a heat sink and as a ground for EMI.

The heat dissipation sheets13are provided on a rear surface of the plasma display panel11to dissipate heat generated from the plasma display panel11due to gas discharge.

The chassis base15is attached to a rear surface of the plasma display panel11using, for example, double-sided tape14with the heat dissipation sheets13interposed between the chassis base15and the plasma display panel11.

The printed circuit board assembles17are mounted on the rear surface of the chassis base15and are electrically connected to the plasma display panel11to drive the plasma display panel11.

The plasma display panel11includes electrodes for gas discharge.FIG. 2shows an exemplary address electrode12of the plasma display panel connected to an address buffer board assembly317among the printed circuit board assemblies17.

The plurality of printed circuit board assemblies17are located on a respective plurality of bosses18and fixed thereto by set screws19. The printed circuit board assemblies17are formed compartmentally to perform respective functions for driving the plasma display panel11.

For example, the printed circuit board assemblies17include a sustain board assembly117controlling a sustain electrode (not shown), a scan board assembly217controlling a scan electrode (not shown), an address buffer board assembly317controlling an address electrode, an image process/control board assembly417generating a control signal for driving the address electrode and a control signal for driving the sustain and scan electrodes by receiving an external image signal and applying the control signals to the corresponding board assemblies, and an electric power source assembly517providing electric power for driving the board assemblies.

FIG. 3is a top view illustrating a connection structure between the address buffer board assembly and the flexible printed circuit. As shown inFIGS. 1 through 3, the address buffer board assembly317is connected to the address electrode12through a flexible printed circuit27. The flexible printed circuit27has a terminal surface generally corresponding to a width of a terminal extending from the address buffer board assembly317. In other words, the terminal of the flexible printed circuit27extends integrally with the terminal extending from the address buffer board assembly317, thereby significantly reducing the likelihood of a connection defect between the flexible printed circuit27and the address buffer board assembly317, as well as reducing the generation of EMI, and preventing a short circuit caused by the inflow of foreign objects.

The address buffer board assembly317may include a low output terminal portion315transmitting a low output logic signal and a high output terminal portion318having an area larger than that of the low-output terminal portion. As the size and definition of the panel increase, the output of the signal transmitted from the address buffer board assembly317to the electrode increases.

In the prior art, in order to input the output signal generated from an address buffer board assembly, a plurality of connector pins are short-circuited into a single pin unit and then connected to the high-output terminal portion of the address buffer board assembly. Therefore, the plasma display device of the prior art transmits the high output signal within a narrow region such as the pin and thus generates high impedance at a connecting portion of the high output terminal, thereby increasing the radiation of EMI. According to test data, it was noted that 54.2 dB EMI, higher than the FFC standard (40 dB), is radiated at a low band of 30 MHz when a connecting portion between the address buffer board assembly and the flexible printed board of a 50-inch high definition (HD) panel was tested.

However, in the plasma display device of the present embodiment, the high output terminal portion for transmitting the high output signal from the address buffer board assembly317is designed to be wide (region A ofFIG. 3) and the terminal of the flexible printed circuit27is formed to correspond to the high output terminal portion318. Therefore, the plasma display device of this embodiment has low impedance at the high output terminal portion318even when a high output signal is transmitted, thereby reducing EMI radiation.

Since the terminal of the address buffer board assembly317is directly connected to the flexible printed circuit27, the terminal of the address buffer board assembly317and the terminal of the flexible printed circuit27are stacked at different heights. Thus, a relatively large number of signals may be transmitted within a limited space. One of the terminals of the address buffer board assembly317may be formed as a ground terminal. The address buffer board assembly317may be a rigid flexible board.

The flexible printed circuit27may be a TCP mounting a driver integrated circuit25generating a control signal applied to the address electrode12to which the flexible printed circuit is connected.

FIG. 5is a perspective view illustrating a connection structure between the plasma display panel and the flexible printed circuit. Referring toFIGS. 1 through 5, an anisotropic conductive film29may be interposed between the terminal of the flexible printed circuit27and the terminal of the address electrode12extending from a dielectric layer of the PDP11, thereby electrically connecting the terminals to each other.

The anisotropic conductive film29is attached to and covers the electrode terminals112and is also attached to and covers a substrate111located around ends of the electrode terminals112. The anisotropic conductive film29covers the electrode terminals112and an alignment mark36provided adjacent one of the electrode terminals112arranged at a side of the substrate111.

Referring toFIG. 5, a first end40of the anisotropic conductive film29is aligned with an end of a dielectric layer21covering the address electrodes12. The anisotropic conductive film extends such that it covers each electrode terminal112extending from the dielectric layer. The terminal of the flexible printed circuit27is located on the anisotropic conductive film29facing the electrode terminal112such that the flexible printed circuit27contacts the electrode terminals112with the anisotropic conductive film29located therebetween. Accordingly, an end42of the anisotropic conductive film29adjacent to an end of the substrate111is aligned with the ends44of the electrode terminals112.

In one exemplary embodiment, conductive members contained in the anisotropic conductive film29electrically connect the electrode terminals112of the plasma display panel11to the electrode of the flexible printed circuit27. More specifically, a polymer material contained in the anisotropic conductive film29is hardened by heat, thereby physically attaching the substrate111of the plasma display panel11to the flexible printed circuit27.

According to embodiments of the plasma display panel of the present invention, even when a high output signal is transmitted due to increased sizes and resolutions of plasma display panels, impedance at the high output terminal is low, and EMI radiation is reduced. Furthermore, since the terminal of the flexible printed circuit extends integrally with the terminal drawn from the address buffer board assembly, the likelihood of a connection defect between the flexible printed circuit and the address buffer board assembly is significantly reduced.

In addition, since the terminal of the flexible printed circuit is assembled simultaneously with the assembly of the address buffer board assembly terminal followed by the terminals being mounted inside the circuit, a short circuit between the terminals caused by foreign objects may be prevented.