EP1215649B1 - Plasma display panel - Google Patents

Description

The present invention relates to an arrangement with a plasma picture screen.

Currently available on the market TVs with plasma screens require considerable effort in terms of the shielding of electromagnetic fields. For example, a solid aluminum or metal housing in conjunction with a metal-coated windscreen is required to meet the legal requirements regarding electromagnetic compatibility. These shielding measures are expensive and increase the weight of the devices.

D1 (T. Yamamoto et al .: "A 40 In Diagonal HDTV Plasma Display" SID International Symposium - Digest of Technical Papers, Seattle, May 16-21, 1993, Playa del Rey, SID, US, Vol Vol. 24, 16 May 1993 (1993-05-16), pp. 165-168, XP000470753 ISSN: 0097-966X) describes a HDTV plasma display with a diagonal of 40 inches, which is produced with a high-precision large-area screen printer. Newly developed hybrid ICs reduce the thickness of the display unit to 8cm.

US 6,366,264 (MASAKAZU KURUMADA), Apr. 2, 2002, describes an arrangement for attaching a driver module to a flat panel display of an image by the driver module, the flat panel being a plasma or liquid crystal display.

U.S. Patent 5,952,986 (NGUYEN THANH NHAN et al.), September 14, 1999, describes an AC-driven plasma display panel having a matrix array of rows and columns with electrode pairs for detecting surface discharge meters.

Patent Abstracts of Japan vol. 1999, no. 05, 31 May 1999 (1999-05-31) - & JP 11 041545 A (Fujitsu General Ltd.), February 12, 1999 (1999-02-12) describes a screen in which interfering electromagnetic radiation is reduced by a wire connecting the plasma display panel and a printed circuit board driving the plasma display panel.

Patent Abstracts of Japan vol. 1997, no. 07, 31 July 1997 (1997-07-31) - & JP 09 062226 A (NEC Corp.), March 7, 1997 (1997-03-07) describes a driver circuit for a flat panel display suitable for a personal computer , a workstation or a flat screen TV is used.

The object of the present invention is to improve the circuits and power supply lines for driving such a plasma picture screen so that the radiation of electromagnetic waves is reduced and additional shielding measures are superfluous.

According to an exemplary embodiment of the present invention, the object is achieved by a plasma display panel having a front translucent panel, a rear wall, cells for generating pixels, X-electrodes and Y-electrodes for contacting the cells, electronic circuits for driving the X's Electrodes and the Y-electrodes and first power supply lines and second power supply lines, wherein the rear wall has an inside and an outside, the cells are arranged between the disk and the inside of the rear wall, the X-electrodes and the Y-electrodes on the Inside the rear wall are arranged, the electronic circuits are arranged on the side facing away from the cells of the rear wall, the first power supply lines for establishing an electrical connection between the X-electrodes and the electronic circuits for driving the X-electrode n are in the region of a first outer edge of the rear wall, the second power supply lines for establishing an electrical connection between the Y-electrodes and the electronic circuits for driving the Y-electrodes in the region of a second outer edge of the rear wall, which lies opposite the first outer edge , are executed, the power supply lines are substantially parallel to each other, the power supply lines terminate in a narrow perpendicular to the power supply lines extending over the entire width of the rear wall contact area, the electronic circuits contact the power supply lines in the narrow contact area and wherein by the narrow configuration of the contact area a Emission of electromagnetic fields is reduced.

This is due to a change in the arrangement of the circuits for driving the plasma screen, the power management between the display boards and the electrodes the pixels of the screen changed so that the radiation is reduced. For this purpose, the power supply lines to the terminals of the electrodes of the plasma display screen are not present as previously only in the peripheral areas of the plasma display screen, but they lead across the entire back of the plasma display screen and ends coming from both sides in a narrow perpendicular to the power lines extending contact area. This area of the plasma screen prevents an antenna-like radiation of electromagnetic fields, since the power lines coming from both sides end up electrically separated from each other. By such an arrangement, in addition, in principle, the radiated electromagnetic fields of the power supply lines to the electrodes interfere with the fields of current flowing on the inside of the rear wall power guides and cancel each other out in the ideal case. Thus, an expensive and weighty shielding as conventional plasma screens is unnecessary. Since both the connections for the electrodes extending on the front screen and for the electrodes extending on the rear wall can be led outwards and attached to the edge of the rear wall, all electrodes can be connected to the current guides according to the invention and lead to the contact region.

By a conductive printed connection as claimed in claim 2, the power supply lines can be produced inexpensively and production-technically simple by being applied to the back of the plasma display screen.

The embodiment according to claim 3 allows the further use of the known existing connections via flexible lines to achieve a shield according to the invention according to claim 1.

According to an exemplary embodiment of the present invention according to claim 4, the current paths to the pads of the electrodes can be shortened by the circuits for driving the pixels are mounted directly on the outside of the rear wall of a plasma display screen. As a result, the leads to the terminals of the electrodes are shortened again. In addition, common buffer capacitors shorten the current paths between the electronic circuits for the driver stages of the X-electrodes and the Y-electrodes. Together with the embodiment of claim 1 so a particularly effective suppression of the radiation of electromagnetic waves is possible. At the same time, a solution with common buffer capacitors is much cheaper than with separate buffer capacitors for each driver stage.

With the embodiment according to claim 5, the advantages of the invention in an end product such as a television or a monitor are applied, which is thereby cheaper to produce.

In accordance with another exemplary embodiment of the present invention, the contact over the entire width of the rear wall is transverse to the current guides such that the radiating surface of the plasma display panel is minimized when viewed from the translucent panel.

• Figur 1 eine schematische Darstellung der einzelnen Komponenten eines Plasmabildschirms,
• Figur 2 ein Blockschaltbild eines herkömmlichen Plasmabildschirms mit eingezeichneten Stromverläufen,
• Figur 3 einen Plasmabildschirm mit einer gemeinsamen Platine für die beiden X-/Y-Treiberstufen mit einem zentralen Anschluss der Stromzuführungen zu den Elektroden des Plasmabildschirms,
• Figur 4a den herkömmlichen Stromverlauf auf der Rückseite eines Plasmabildschirms,
• Figur 4b die verbesserte Stromführung auf der Rückseite eines Plasmabildschirms,

Embodiments of the invention are explained in more detail below with reference to some figures. Show it:

• FIG. 1 shows a schematic representation of the individual components of a plasma picture screen;
• FIG. 2 shows a block diagram of a conventional plasma screen with drawn current profiles,
• 3 shows a plasma screen with a common board for the two X / Y driver stages with a central connection of the power supply lines to the electrodes of the plasma display screen, FIG.
• FIG. 4 a shows the conventional current profile on the rear side of a plasma picture screen;
• FIG. 4b shows the improved current conduction on the rear side of a plasma picture screen;

As can be seen in FIG. 1, an arrangement according to the invention primarily consists of the actual plasma picture screen 3, on whose rear side power supply lines 2 are present, which connect the plasma picture screen 3 to the electronic circuits for controlling the picture elements of the plasma picture screen 3. The electronic circuits consist inter alia of the two driver stages 6, 7, which control the two different electrode groups, the X-electrodes and the Y-electrodes. The driver stages receive their power from a supply module 8, e.g. a switching power supply. By means of further circuits 4, 9, the pixels are selected, wherein the circuit 4, the rows of the plasma display panel 3 selects and the circuit 9 selects the columns. The selection of the pixels is done by the two circuits 4, 9 as a function of the applied image information. These are provided by a circuit 5 for image processing.

If a pixel is activated, the pixel lights up, and relatively high and, above all, high-frequency currents flow through the electrodes and the current leads 2 and through the current leads between the contacts 13 and the individual electrodes of the pixels. In this case, electromagnetic waves are emitted from the current-carrying connections 2. These are indicated in Figure 2 by thick black lines, while in the dashed lines flow only weak currents whose electromagnetic fields are negligible. The high currents span with the associated return currents on an area, with a large area means a high electromagnetic radiation. Therefore, with the present invention, these areas are reduced, so that compensate the electromagnetic fields of the outflowing streams and the refluxing streams as far as possible. After a certain distance from the plasma picture screen 3, the fields cancel each other as well as on. In addition, the contacting of the power supply lines 2 with the driver stages 6, 7 takes place in a narrow contact area 14. Thus, the ends of the power supply lines 2 coming from both sides can not act like antennas and emit electromagnetic waves. The best effect is therefore achieved when the power supply ends electrically isolated from each other immediately adjacent to each other. The contact area 14 can also be moved from the center, but it is important that it extends across the entire width of the rear wall 11 transversely to the power supply lines.

For a particularly small radiating surface, the power supply lines 2 are applied directly as a conductive coating on the back of the rear wall 11. The rear wall 11 is currently for reasons of statics made of glass, but can also be made of a temperature-resistant other material, since a transparency is not required and on the contrary pass light from the pixels to the rear, which is undesirable.

The decisive advantage thus offers the novel structure of the power supply lines 2. While in conventional plasma screens the driver stages 6, 7 are accommodated for the X and Y electrodes on separate boards and at voltage transitions, the currents are passed through the grounding return, omitted Arrangement according to the invention on such a power supply via the ground return. Furthermore, the driver boards 6, 7 are arranged centrally and connected via power supply lines 2 with the X / Y electrodes. This can be achieved in that, as in FIG. 1, the power supply lines 2 (in this case flexible lines) for the X / Y electrodes are led to the center of the plasma picture screen 3 on the rear side thereof. By means of separate plug-in connections, they are connected there to the driver stages 6, 7.

To further shorten the current paths, it makes sense to combine the driver stages 6, 7 on a common board. This can be seen in FIG. As a result, the radiation of electromagnetic waves is reduced by transfer currents between the driver stages 6, 7. Furthermore, the power supply lines 2 for the X / Y electrodes can now be connected via a common connector to the driver stages 6, 7. At the same time, the two driver stages 6, 7 use common buffer capacitors 1, whereby half of the capacitors can be saved.

A further improvement is possible in that the row selection circuit 4 is no longer mounted on the flexible leads of the current leads 2 but directly on the back wall 11 of the plasma display panel 3. The current leads 2 between Y electrodes and the circuit 4 are available for selection the rows as well as its connection with the X / Y driver stages 6, 7 can then take place through a conductive layer on the rear wall 11 of the plasma picture screen 3 as in FIG. 4b; Figure 4a shows the conventional leads 2. The connection of the plasma display panel 3 to the driver stages 6, 7 is inexpensive by connectors and contact springs or other conductive flexible materials possible, which have direct contact with the conductive layer of the power supply lines 2. In addition to the reduction of the radiating surface, such an arrangement also offers the advantage of increased magnetic coupling, which improves the current distribution of the refluxing currents.

Considering the radiating surface of the entire arrangement of the glass pane 10 of the front of the plasma display panel 3, this is then minimal, when the contact area extends over the entire vertical center line of the plasma display panel 3. The streams are then not concentrated towards the contact points. For this purpose, the power supply lines 2 of each individual X-electrode and each Y-electrode on the front glass pane 10 are separated rearwardly on the outside of the rear glass pane 11 of the plasma display panel 3 and there to about the middle, where they with the electronic circuits (driver stages ) 4, 6, 7 are contacted. This is done in the same way with a narrow contact area 14 over the entire width as in the embodiment according to claim 1. The stage 4 for controlling the rows can then also accommodated together with the X / Y driver stages 6,7 on a common board be.

Of course, instead of the front glass pane 10, a transparent plastic pane or film may also be used if the stability of the entire plasma display screen 3 is ensured.

Claims (6)

1. A plasma display panel, having
   on the front side a translucent plate (10);
   a rear wall (11);
   cells for generating picture elements;
   X electrodes and Y electrodes;
   electronic circuits (4, 6, 7) for driving the X electrodes and the Y electrodes;
   first power supply leads and second power supply leads;
   characterized in that the rear wall (11) has an inside and an outside;
   in that the cells are arranged between the screen and the inside of the rear wall (11);
   in that the X electrodes and the Y electrodes are arranged on the inside of the rear wall (11);
   in that the electronic circuits (4, 6, 7) are installed in the outside of the rear wall facing away from the cells;
   in that the first power supply leads are provided for establishing an electrical connection between the X electrodes and the electronic circuits for driving the X electrodes in the area of a first outside of the rear wall (11);
   in that the second power supply leads are provided for establishing an electrical connection between the Y electrodes and the electronic circuits for driving the Y electrodes in the area of a second outside of the rear wall (11), opposite to the first outside;
   in that the power supply leads (2) largely run parallel with each other;
   in that the power supply leads (2) end in a narrow contact area (14) running at a right angle to the power supply leads (2) over the whole width of the rear wall (11);
   in that the electronic circuits (4, 6, 7) contact the power supply leads (2) in the narrow contact area (14); and
   in that an emission of electromagnetic fields is reduced as a result of the narrowness of the contact area (14).
2. A plasma display panel as claimed in claim 1, characterized in that the power supply leads (2) take the form of conductor tracks deposited on the outer side of the rear wall (11), which outer side is remote from the cells.
3. A plasma display panel as claimed in claim 1, characterized in that the power supply leads (2) take the form of cables.
4. A plasma display panel as claimed in claim 1, characterized in that the electronic circuits (4, 6, 7) are further arranged for driving rows of the plasma display panel (3); and in that the electronic circuits (4, 6, 7) include shared buffer capacitors (1) for driving the X electrodes and the Y electrodes.
5. A plasma display panel as claimed in claim 1 or 4, characterized in that this arrangement is a television set or a monitor.
6. A plasma display panel as claimed in claim 1 or 4, characterized in that the contact area (14) runs over the whole vertical diameter of the plasma display panel (3).

Images