Moon, Seok Joon (257 Gongdan-dong, Gumi-si, 730-904 Gyoungsangbuk-do, KR)
| 1. | An ACplasma display panel for a multiscreen, comprising a plurality of discharge cells having address electrodes and X and Y electrode pairs, and barrier ribs for dividing each discharge cell, the plasma display panel having a barrier rib structure wherein a pitch between the barrier ribs gradually increases depending on moving direction of a pulse waveform applied to at least one of the electrodes. |
| 2. | The panel according to claim 1, wherein the barrier ribs are divided into a plurality of regions depending on arrangement sequence, and the pitch between the barrier ribs are differently formed in each region. |
| 3. | The panel according to claim 1 or 2, wherein the pitch between the barrier ribs increases at a predetermined ratio as the barrier ribs become farther from electrode pads for receiving the pulse waveform. |
| 4. | The panel according to claim 1 or 2, wherein the X and Y electrodes are fetched to one side of the panel, thereby receiving the pulse waveform. |
[Background Art] A PDP is a light-emitting device that projects images by exciting a fluorescent substance formed in a discharge cell. The PDP is lighter than a conventional cathode ray tube, and a process for manufacturing the plasma PDP is simple. Moreover, due to its simplicity in producing a slim and large screen, demands for the PDP are tending upward in use of a status bulletin board at the stock exchange, a display for videoconferences, and a wall mounted wide TV set.
Fig. 1 is a perspective view of a disassembled PDP, and Fig. 2 shows a structure where X and Y electrodes are fetched to one direction in the PDP used for configuration of a multi-screen.
In the PDP, a front substrate 10 whereon X and Y electrodes are formed is sealed in parallel with a rear substrate 20 whereon an address electrode is formed.
On the front substrate 10, X and Y electrodes are formed for sustaining light emission of cells by inter-discharge in one pixel. The X and Y electrodes comprise transparent electrodes (or ITO electrodes) (Xa, Ya) formed of transparent ITO materials and bus electrodes (Xb, Yb) formed of metal materials.
The X and Y electrodes are covered by a dielectric layer 12 for restricting discharge current and insulating a space between electrode pairs. A protective layer 13 is formed on the dielectric layer.
On the rear substrate 20 are arranged in parallel barrier ribs 21 having a stripe type (or dot type) for forming a plurality of discharge spaces, that is cells C. The address electrode A is arranged in parallel with the barrier ribs 21, crossed with the electrodes X and Y. A dielectric layer 23 is formed on the address electrode A.
Furthermore, a R. G. B fluorescent layer 24 which radiates visible radiation in order to display images at address discharge is covered on the top of the rear substrate 20 except the top cross section of the barrier rib 21.
However, due to technical restraint or equipment limitation, the plasma display panel has been developed in the size 63 inches at largest to date.
The commercial display requires conditions to be wide, slim, and highly bright.
Therefore, the conventional 63 inch commercial display is too small in size matter, and
needs for a larger size have been continuously desired.
In order to meet the requirements, a plurality of plasma display panels are arranged so that a multi screen device forms large screen. For this configuration, a PDP is used where X and Y electrodes are fetched to one direction. In case of arranging 4 PDPs for a large screen, as shown in Fig. 2, X and Y electrodes are fetched not to the edge of the PDPs contacting each other but to one direction, thereby closely connecting PDPs without any gap between the PDPs.
When a pulse is applied through these electrodes by fetching electrodes to one direction, impedance of electrodes increases as the barrier ribs become farther from electrode pads for receiving the pulse, which results in distortion of the pulse. However, in the PDP for a multi-screen, the barrier ribs 21 are arranged at a predetermined interval, crossed with the electrodes like in the PDP for a single screen.
The pulse applied from the electrode pad is severely distorted as the barrier rib is closer to the opposite edge of the electrode pad. However, since the pitch between the barrier ribs is constant, the discharge spaces C are formed to have the same size. As a result, lead-in terminals for receiving the pulse have a brightness difference and a discharge voltage difference in discharge cells (discharge regions).
The local increase of the discharge voltage disables driving at the same voltage in driving the whole panels, thereby reducing the operation margin and yield.
[Brief Description of the Drawings] Fig. 1 is a perspective view of a disassembled plasma display panel.
Fig. 2 is a diagram showing an electrode structure of a PDP wherein X and Y electrodes are fetched to one direction for configuration of a multi-screen device.
Fig. 3 is a diagram showing a PDP having a different pitch between barrier ribs in each region.
[Detailed Description of the Invention] Accordingly, it is an object of the present invention to provide a PDP wherein X and Y electrodes are fetched to one direction, which may minimize a discharge voltage difference and a brightness difference in each region of the PDP due to distortion of a pulse applied to the X and Y electrodes.
In order to achieve the above-described object of the present invention, there is provided a plasma display panel comprising a plurality of discharge cells having address electrodes and X and Y electrode pairs, and barrier ribs for dividing each discharge cell.
Here, the plasma display panel has a barrier rib structure wherein a pitch between the barrier ribs gradually increases depending on moving direction of a pulse waveform applied to at least one of the electrodes.
[Preferred Embodiments] In an embodiment of the present invention, a plurality of interconnected PDPs, which are used in a large display device. As shown in Fig. 2, X and Y electrodes are fetched to one direction for close adhesion of PDPs. A plurality of X and Y electrode pairs are alternately arranged in parallel.
Fig. 3 is a diagram showing a PDP having a different pitch between barrier ribs in each region.
As shown in Fig. 3, pitches between barrier ribs are differently formed, crossed with X and Y electrodes (not shown) depending on distance from electrode pads for receiving pulse waveforms. As the barrier ribs become farther from the electrode pads, the pitches between the barrier ribs increases to broaden discharge spaces.
The region (1) which is adjacent to the electrode pad corresponds with start ends of electrodes X and Y, and has the minimum pitch. The region (3) which becomes farthest from the electrode pads corresponds with final ends of the X and Y electrodes, and has the maximum pitch.
The region (2) is an intermediate region of the regions (D and 3). The pitch of the region (2) is determined by increase degree of the pitch between the barrier ribs of the regions (D and, (3)... Here, the. maximum-barrier, rib pitch is preferably two times. smaller than the minimum barrier rib pitch. In case of 42"plasma display panel, when the electrode is fetched to one direction, the brightness difference generated between the regions (t) and 3) shows 40% un-uniformity experimentally. Additionally, the brightness of the region (D can be regulated to be two times larger or smaller than that of the region 3.
In another embodiment where a pitch between barrier ribs is differentiated in each region, as the barrier ribs become farther from electrode pads, the pitch is made to be broadened gradually at a predetermined ratio in each R, G, B fluorescent material cell.
Otherwise, after the PDP is divided into several regions according to the moving direction of the pulse applied to electrode pads, a pitch between barrier ribs is made to be constant in each region and the pitch is made to increase gradually between the regions.
Any of conventional methods for forming barrier ribs can be used as a method for forming barrier ribs. However, the pitch between barrier ribs is required to be properly regulated in the patterning process.
The method for forming barrier ribs includes a screen print method, a sandblast method, a LTCC-M (Low Temperature Cofired Ceramic on Metal) method and a direct etching method.
Although the barrier rib structure is a stripe type in the above-described embodiment, a grid type as the barrier rib structure may be applied to any embodiments.
[Industrial Applicability] As discussed earlier, a pitch between barrier ribs is differently formed in each region of a PDP, thereby reducing a brightness difference in each region of the PDP and improving the quality of the PDP, especially in uniformity of a multi-screen.
Additionally, the whole discharge voltage is made to be uniform, thereby obtaining the broad operation margin and improving the yield.