KR100590082B1 - Plasma display panel - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a plasma display panel having an electrode structure advantageous for realizing a high density and high luminance display.

A plasma display panel according to the present invention includes: a first substrate and a second substrate disposed to face each other; Address electrodes formed on the first substrate in parallel with one direction; A partition wall disposed between the first substrate and the second substrate and partitioning a plurality of discharge cells; A phosphor layer formed in each of the discharge cells; First and second electrodes corresponding to each discharge cell while extending in a direction crossing the address electrode on the second substrate; And a third electrode disposed to be spaced apart from the first electrode and the second electrodes, protruding toward the first substrate in a direction away from the second substrate, and formed to face each other with a space therebetween; And fourth electrodes, wherein the third electrode has the same potential as the first electrode, and the fourth electrode has the same potential as the second electrode.

Plasma, display, counter discharge, electrostatic coupling, protruding electrode

Description

Plasma Display Panel {PLASMA DISPLAY PANEL}

1 is a graph schematically showing a voltage distribution between a cathode and an anode in a typical glow discharge.

2 is a partially exploded perspective view showing a PDP according to an embodiment of the present invention.

3 is a partial plan view schematically illustrating a structure of an electrode and a discharge cell in a PDP according to an embodiment of the present invention.

4 is a partial cross-sectional view taken along the line A-A by combining the PDP shown in FIG.

5 is a partial cross-sectional view showing in detail the front plate structure of the PDP according to the first embodiment of the present invention.

FIG. 6 is a partial cross-sectional view taken along line B-B of FIG. 3.

7 (a) to 7 (d) are partial cross-sectional views schematically showing sizes and positions of cathode spots and anode spots with time after discharge start in a PDP according to the first embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a plasma display panel having an electrode structure advantageous for realizing a high density and high luminance display.

In general, a plasma display panel (hereinafter referred to as a 'PDP') is used to implement an image using visible light generated by a vacuum ultraviolet ray (VUV) emitted from a plasma obtained through gas discharge. Display element. Such a PDP can realize an ultra-large screen of 60 inches or more with a thickness of only 10 cm or less, and is a self-luminous display device such as a CRT. In addition, the manufacturing method is simpler than LCD, and thus has advantages in terms of productivity and cost.

The structure of the PDP has been developed for a long time since the 1970s, and the structure generally known is a three-electrode surface discharge type structure. The three-electrode surface discharge type structure consists of one substrate including two electrodes located on the same surface and another substrate including address electrodes vertically spaced apart from each other at a predetermined distance therebetween, with a discharge gas enclosed therebetween. Structure. In general, the presence or absence of the discharge is determined by the discharge of the address electrode facing the scan electrode independently connected to each line, and the sustain discharge indicating the luminance is performed by two electrode groups located on the same plane. .

PDP uses a glow discharge to make visible light visible to humans, which takes several steps to reach the human eye after the glow discharge occurs. That is, when a glow discharge occurs, an excited gas is generated by collision between electrons and gases, and ultraviolet rays are generated from the excited gas. Ultraviolet rays collide with the phosphor in the discharge cell to generate visible light, and the visible light passes through the transparent substrate on the front surface and reaches the human eye. This step results in a significant loss of input power.

Glow discharges are usually obtained by applying a voltage above the discharge start voltage between two electrodes under a low atmospheric pressure (<1 atm). The discharge start voltage is a function of the type of gas, the atmospheric pressure, and the distance between electrodes. In the case of AC discharge, in addition to these three, the discharge start voltage is also affected by the dielectric capacitance (dielectric constant, electrode area, dielectric thickness) and the frequency of the applied voltage.

Although a very high voltage is required to initiate the discharge, the voltage distribution between the cathode and the anode is distorted as shown in FIG. 1 due to the difference in the space charge generated around the cathode and the anode once the discharge occurs. FIG. 1 shows that most of the voltage is being consumed around two electrodes, that is, in areas called cathode sheath and anode sheath, and in the relatively positive column region. It can be seen that the amount of voltage is small. In particular, the glow discharge generated in the PDP is known that the voltage consumed in the cathode sheath is much higher than the voltage of the anode sheath.

The emission of visible light in the phosphor is caused by the collision of the ultraviolet light with the phosphor, and the ultraviolet light is generated when the energy level is changed from the excited state of Xen to the ground state of Xen. . On the other hand, xenon Xe in an excited state is made by collision between Xen in stable state and electrons. Therefore, in order to increase the ratio of generating visible light among the input energy, that is, the luminous efficiency, the electron heating efficiency must be increased.

In general, since the electron heating efficiency in the positive column region is higher than the electron heating efficiency in the cathode sheath region, the improvement of the PDP luminous efficiency is possible by increasing the positive column region. Since the sheath region has almost the same thickness under the same pressure, it is necessary to increase the length of the discharge in order to increase the luminous efficiency.

In the case of a PDP having a three-electrode structure, discharge is initiated in the region closest to the two electrodes-at the center of the discharge cell-and the discharge then moves to the edge region of the electrode. The discharge occurs in the center region because the discharge start voltage in this region is low. In general, the discharge start voltage is a function of the product of the pressure and the distance between the electrodes, and the PDP operating region is located to the right of the minimum value of the Paschen curve. Once the discharge is initiated, the discharge is maintained under a voltage much lower than the discharge start voltage due to the formation of space charge, and the voltage between the two electrodes gradually decreases with time. After the start of the discharge, the intensity of the electric field is weakened as ions and electrons accumulate in the central region, and the discharge disappears in this region.

Cathode and anode spots move over time in areas free of surface charge, ie around the electrode edges. At this time, since the voltage applied between the two electrodes decreases with time, strong discharge occurs in the center region of the discharge cell (low light emitting efficiency), and weak discharge occurs near the edge of the discharge cell (high light emitting efficiency). . Based on the same principle, the conventional three-electrode surface discharge structure has a low ratio used for heating electrons among the input energy, resulting in low luminous efficiency.

In order to overcome the weakness of the three-electrode structure, a method of increasing the distance between the display electrodes may be considered, but this causes an increase in the discharge start voltage.

The present invention was devised to solve the above problems, and an object thereof is to form a metal electrode closer to the phosphor layer at the edge of the discharge cell to mitigate the degree of decrease in the intensity of the discharge near the edge of the discharge cell. It is to provide a plasma display panel that can be.

Another object of the present invention is to provide a plasma display panel having a discharge cell structure capable of inducing a sustain discharge generated between a pair of display electrodes to a counter discharge in order to overcome the disadvantages of discharge caused by the smaller size of the discharge cell. To provide.

In order to achieve the above object, a plasma display panel according to the present invention comprises: a first substrate and a second substrate facing each other; Address electrodes formed on the first substrate in parallel with one direction; A partition wall disposed between the first substrate and the second substrate and partitioning a plurality of discharge cells; A phosphor layer formed in each of the discharge cells; First and second electrodes corresponding to each discharge cell while extending in a direction crossing the address electrode on the second substrate; And a third electrode disposed to be spaced apart from the first electrode and the second electrodes, protruding toward the first substrate in a direction away from the second substrate, and formed to face each other with a space therebetween; And fourth electrodes, wherein the third electrode has the same potential as the first electrode, and the fourth electrode has the same potential as the second electrode.

The third electrode and the fourth electrode are formed on different layers from the layer where the first electrode and the second electrode are formed, and the first electrode 21 and the second electrode 22 and the dielectric layer are interposed therebetween. Are spaced apart.

The third electrode and the fourth electrode are formed such that each end of the first substrate protrudes toward the first substrate more than the surface of the dielectric layer corresponding to the center of the discharge cell, and extends in a direction crossing the address electrode. Is formed.

The first electrode and the third electrode may be formed by electrically shorting the terminal portions with each other, and the second electrode and the fourth electrode may be formed by electrically shorting the terminal portions with each other.

A first dielectric layer is formed on the second substrate to cover the first electrode and the second electrode, and the third electrode and the fourth electrode are formed on the first dielectric layer, and the third electrode and the fourth electrode are respectively formed. A second dielectric layer is formed to surround. In this case, the second dielectric layer may be made opaque.

The third electrode and the fourth electrode may be formed to pass over the discharge cells adjacent to the edge of each discharge cell.

Each of the first electrode and the second electrode includes a bus electrode corresponding to each discharge cell while extending in a direction crossing the address electrode, and an enlarged electrode extending from the bus electrode toward the center of each discharge cell. In this case, the third and fourth electrodes may be disposed at positions overlapping the bus electrodes of the first and second electrodes, respectively, when viewed from the front of the panel.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

2 is a partially exploded perspective view showing a PDP according to an embodiment of the present invention, Figure 3 is a partial plan view schematically showing the structure of the electrode and the discharge cell. 4 is a partial cross-sectional view taken along the line A-A by combining the PDP shown in FIG.

As shown, the PDP according to the present embodiment basically has a predetermined interval between the first substrate 10 (hereinafter referred to as the 'back substrate') and the second substrate 20 (hereinafter referred to as the 'front substrate'). They are disposed to face each other, and a plurality of discharge cells 18 are partitioned by the partition wall 16 in the space between the substrates 10 and 20. In the discharge cell 18, a phosphor layer 19 that absorbs ultraviolet rays and emits visible light is formed along the partition walls and the bottom surface, and discharge gas (eg, xenon (Xe), neon ( Ne) and the like (mixed gas) are filled.

Address electrodes 12 are formed along one direction (y-axis direction of the drawing) on the opposite surface of the front substrate 20 of the rear substrate 10, and cover the entire address surfaces of the rear substrate 10 while covering the address electrodes 12. A dielectric layer 14 is formed in the. The address electrodes 12 are formed in parallel with each other while maintaining a predetermined distance from neighboring ones.

The partition wall 16 is formed over the dielectric layer 14 formed on the rear substrate 10. In the present embodiment, the partition wall 16 includes a first partition member 16a extending in a direction parallel to the address electrode 12; The second partition member 16b is formed to intersect the first partition member 16a and partitions each discharge cell 18 into an independent discharge space. The barrier rib structure is not limited to the above-described structure, and the barrier rib structure having only the barrier member in parallel with the address electrode may be applied to the present invention, and the barrier rib structure having various shapes for partitioning the discharge cells may be used. It also belongs to the scope of the present invention.

Meanwhile, referring to FIG. 3, the first electrode 21 and the first electrode 21 are formed on the inner surface of the front substrate 20 opposite to the rear substrate 10 along the direction crossing the address electrode 12 (the x-axis direction of the drawing). The two electrodes 22 are formed to extend each other. In the present exemplary embodiment, each of the first electrode 21 and the second electrode 22 extends along the direction crossing the address electrode 12, and the bus electrodes 21b and 22b corresponding to the respective discharge cells 18 are formed. And expansion electrodes 21a and 22a extending from the bus electrodes 21b and 22b toward the center of each discharge cell 18 to form a predetermined discharge gap g. In this case, the bus electrodes 21b and 22b may be made of metal electrodes, and the enlarged electrodes 21a and 22a may be made of transparent electrodes such as indium tin oxide (ITO) electrodes to secure the aperture ratio.

A pair of the first electrode 21 and the second electrode 22 correspond to each discharge cell 18 to participate in the discharge of the sustaining period, and one of the first and second electrodes 21 and 22 is Together with the address electrode 12, it is involved in the discharge of the address section. However, the electrodes do not need to be limited to the above because they may have different roles depending on the signal voltage applied thereto.

Referring to FIG. 4, in the present embodiment, the front substrate 20 is spaced apart from the first electrode 21 and the second electrode 22 so that the third electrode 23 and the fourth electrode 24 are separated from each other. Is formed. These third and fourth electrodes 23 and 24 are disposed at positions substantially overlapping with the bus electrodes 21b and 22b of the first and second electrodes, respectively, when viewed from the front of the panel. In addition, the second electrodes 21 and 22 are spaced apart from the front substrate 20 to protrude toward the rear substrate 10 in a direction away from the negative z-axis direction of the drawing. The protruding third electrode 23 and the fourth electrode 24 are formed to face each other with a space therebetween, and the space is between the third electrode 23 and the fourth electrode 24 facing each other. Counter discharge can be induced. Preferably, the third electrode 23 and the fourth electrode 24 are made of a metal electrode.

In the present embodiment, the third electrode 23 and the fourth electrode 24 are formed on layers different from those on which the first electrode 21 and the second electrode 22 are formed. That is, the first dielectric layer 28a is formed on the front substrate 20 to cover the first electrode 21 and the second electrode 22, and the third electrode 23 and the third electrode 23 are formed on the first dielectric layer 28a. Four electrodes 24 are formed, and a second dielectric layer 28b is formed to surround these third and fourth electrodes 23 and 24. In this case, the first dielectric layer 28a is preferably made of a transparent dielectric material to emit visible light generated in the discharge cells 18 to the outside. The second dielectric layer 28b may be made of the same material as the first dielectric layer 28a, and may optionally be opaque to form the second dielectric layer 28b to improve the clear contrast of the PDP.

As described above, the third electrode 23 and the fourth electrode 24 are formed to protrude, and the second dielectric layer 28b is formed to surround them, and dielectric blocks are formed between the discharge cells 18 adjacent to each other. This dielectric block prevents ions and electrons from moving between neighboring discharge cells 18, significantly reducing the occurrence of crosstalk and thus reducing misdischarge between on-off cells.

The bus electrodes 21b and 22b of the first electrode 21 and the second electrode 22 are formed to pass over the discharge cell 18 adjacent to the edges of the respective discharge cells 18 and the third electrode. The 23 and fourth electrodes 24 are formed to extend in the direction crossing the address electrode 12 at positions corresponding to the bus electrodes 21b and 22b. That is, the third electrode 23 and the fourth electrode 24 are also formed to pass over the discharge cell 18 adjacent to the edge of each discharge cell 18, except that the first electrode 21 and the second electrode 24 are formed. The electrode 22 is spaced apart from each other with a dielectric layer interposed therebetween.

The MgO protective layer 29 may be formed on the first dielectric layer 28a and the second dielectric layer 28b to protect the dielectric layer from collision of ions of the ionized atoms during plasma discharge. The MgO protective layer 29 also has an advantage of increasing discharge efficiency because the emission coefficient of secondary electrons is high when ions collide with each other.

5 is a partial cross-sectional view showing in detail the front plate structure of the PDP according to the first embodiment of the present invention.

In this embodiment, in order for the opposite discharge to occur easily between the third electrode 23 and the fourth electrode 24, the end of the rear substrate 10 side of the third electrode 23 (or the fourth electrode 24) is formed. The surface of the first dielectric layer 28a corresponding to the center of the discharge cell 18 should protrude more toward the rear substrate 10, and the thickness direction of the panel than the bus electrodes 21b and 22b of the first and second electrodes. It is preferable that the thickness measured in the (z-axis direction in the drawing) is thicker. That is, referring to FIG. 5, the conditions δ> 0 and H (b) <H (m) are satisfied. Here,? Represents the length of the third electrode 23 (or the fourth electrode 24) protruding from the surface of the first dielectric layer 28a, and H (b) is a bus measured from the front substrate 20 surface. The thickness of the electrodes 21b and 22b is shown, and H (m) represents the thickness which measured the 3rd electrode 23 (or the 4th electrode 24) in the thickness direction of a panel.

In order to manufacture the front plate structure, the dielectric layer surrounding the electrode installed on the front substrate 20 may be dug by sandblasting, or the dielectric layer may be partially cut out by using a photosensitive dielectric or a green sheet. Alternatively, the electrode part including the third electrode 23 and the fourth electrode 24 is separately manufactured by using a thick film ceramic sheet (TFCS) technique, and then the first electrode 21 and the second electrode 22 are formed. It can also be manufactured by coupling to the front substrate 20.

The cross section which cut | disconnected the 3rd electrode 23 and the 4th electrode 24 in the plane perpendicular | vertical to the longitudinal direction, respectively, has a board | substrate surface rather than the length W (m) in the direction parallel to the substrate surface (y-axis direction of drawing). The length H (m) in the vertical direction (z-axis direction in the figure) may be longer. In other words, the height from the front substrate 20 surface of the third electrode 23 and the fourth electrode 24 can be made higher. In this case, when the size of the discharge cell needs to be reduced in order to implement a high-definition display, the height of the third electrode 23 and the fourth electrode 24 can be compensated for this.

Meanwhile, when the second dielectric layer 28b is formed to surround the third electrode 23 and the fourth electrode 24, as shown in FIG. 5, the third electrode 23 and the fourth electrode 24. The thickness of the second dielectric layer 28b formed on the surface where the third electrode 23 and the fourth electrode 24 face the back substrate 10 rather than the thickness W1 of the second dielectric layer 28b formed on the opposite surface. (H1) may be formed thicker. In addition, the third electrode 23 and the fourth electrode 24 is formed between the different electrodes between the discharge cells 18 adjacent to the thickness (W1) of the second dielectric layer 28b formed on the opposite surface The thickness W2 of the second dielectric layer 28b may be made larger. Through this structure, it is possible to prevent erroneous discharge from occurring between the electrodes located in the adjacent discharge cells during the sustain discharge.

Meanwhile, in the present embodiment, the third electrode 23 has the same potential as the first electrode 21, and the fourth electrode 24 has the same potential as the second electrode 22.

The third electrode 23 and the first electrode 21 may be electrically shorted to each other by terminal portions of electrodes positioned at edges of the panel, and may apply the same voltage V1 through the common terminal portion. Alternatively, it is also possible to apply the same voltage V1 to each electrode from a driving circuit section (not shown) without forming a common terminal section.

FIG. 6 is a partial cross-sectional view taken along line BB of FIG. 3 and illustrates that the first electrode 21 and the third electrode 23 have a common terminal portion, and the same voltage V1 is applied through the terminal portion. As shown.

Similarly, the fourth electrode 24 and the second electrode 22 are electrically shorted to each other between the terminal portions of the electrodes positioned at the edge of the panel, and can apply the same voltage V2 through this common terminal portion. Therefore, it is also possible to apply the same voltage V2 to each electrode from the driving circuit section (not shown) without forming a common terminal section.

That is, the same voltage V1 is applied to the first electrode 21 and the third electrode 23, and the first and third electrodes 21 and 23 are applied to the second electrode 22 and the fourth electrode 24. By applying the same voltage V2 that is different from the voltage applied to, the same potential can be maintained, respectively.

7 (a) to 7 (d) are partial cross-sectional views schematically showing sizes and positions of cathode spots and anode spots with time after discharge start in a PDP according to the first embodiment of the present invention.

After the discharge D is initiated in the region closest to the first electrode 21 and the second electrode 22 formed on the front substrate 20-the center of the discharge cell 18-to accumulate ions and electrons. As a result, the voltage applied to the discharge gap g decreases, and accordingly, the cathode spot and the anode spot move to an area without surface charge, that is, an edge area of the discharge cell 18. At this time, the voltage applied to the discharge gap g decreases with time, so the intensity of the discharge becomes weak. (See FIG. 7 (a), (b))

In the structure according to the present embodiment, unlike the conventional three-electrode structure in which the discharge is turned off at the edge region of the discharge cell 18, the discharge is performed to the third and fourth electrodes 23 and 24 provided at the edge of the discharge cell 18. This transfers In the third and fourth electrodes 23 and 24, since discharge occurs more easily than the bus electrodes 21b and 22b between the third electrode 23 and the fourth electrode 24 utilizing the opposite discharge. The discharge intensity of is only slightly weaker as compared with the discharge on the surfaces of the bus electrodes 21b and 22b. Discharge is maintained for a long time as the cathode spot and the anode spot move from the top vicinity to the bottom side of the third and fourth electrodes 23 and 24, and the surface charge is applied to the third and fourth electrodes 23 and 24. After enough accumulation in the dielectric layer, the discharge disappears. (See Fig. 7 (c), (d))

As such, when the two electrodes are the same, since the discharge start voltage in the counter discharge electrode structure is much lower than that of the coplanar discharge electrode structure, discharge is likely to occur. The discharge transition from the first and second electrodes 21 and 22 installed in the 20 to the third and fourth electrodes 23 and 24 is easy. Therefore, there is an advantage that the discharge is maintained for a long time in the region having a long discharge path with good luminous efficiency-near the edge of the discharge cell.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications or changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. It goes without saying that it belongs to the scope of the present invention.

As described above, according to the plasma display panel according to the present invention, the structure of the electrode involved in the discharge inside the discharge cell has a surface discharge structure at the center of the discharge cell, and has an opposite discharge structure at the edge of the discharge cell. The initiated discharge can be easily transferred to the discharge cell edge electrode. Therefore, the discharge is maintained for a long time near the edge of the discharge cell, which is a region having a long discharge path with good luminous efficiency.

In addition, the dielectric layer formed to surround the electrodes constituting the opposite discharge structure forms a dielectric block between discharge cells adjacent to each other, thereby preventing crosstalk from occurring due to preventing ions and electrons from moving between neighboring discharge cells. (on-off) can reduce the mis-discharge between cells.

In addition, by forming an opaque dielectric layer surrounding the electrode forming the opposite discharge structure, there is an effect that can improve the clear room contrast of the PDP.

Claims (12)

A first substrate and a second substrate disposed to face each other; Address electrodes formed on the first substrate in parallel with one direction; A partition wall disposed between the first substrate and the second substrate to partition a plurality of discharge cells; Phosphor layers formed in the discharge cells; First and second electrodes corresponding to each discharge cell while extending in a direction crossing the address electrode on the second substrate; And A third electrode and a second electrode which are disposed to be spaced apart from the first electrode and the second electrode, protrude toward the first substrate in a direction away from the second substrate, and are formed to face each other with a space therebetween; 4 electrodes Including, And the third electrode has the same potential as the first electrode, and the fourth electrode has the same potential as the second electrode. The method of claim 1, The third electrode and the fourth electrode are formed on a layer different from the layer on which the first electrode and the second electrode are formed. The method of claim 1, The third electrode and the fourth electrode are spaced apart from each other with the first and second electrodes 21 and 22 interposed therebetween with a dielectric layer therebetween. The method of claim 1, The third electrode and the fourth electrode, wherein each end of the first substrate side protrudes toward the first substrate more than the surface of the dielectric layer corresponding to the center of the discharge cell. The method of claim 1, And the third electrode and the fourth electrode are formed to extend in a direction crossing the address electrode. The method of claim 1, And the first and third electrodes are electrically shorted to each other. The method of claim 1, The second electrode and the fourth electrode plasma display panel electrically shorted to each other. The method of claim 1, A first dielectric layer is formed on the second substrate to cover the first electrode and the second electrode, and the third electrode and the fourth electrode are formed on the first dielectric layer, and the third electrode and the fourth electrode are respectively formed. And a second dielectric layer formed to surround the plasma display panel. The method of claim 8, And the second dielectric layer is opaque. The method of claim 1, And the third electrode and the fourth electrode are formed to pass over the discharge cells adjacent to the edge of each discharge cell. The method of claim 1, Each of the first electrode and the second electrode includes a bus electrode corresponding to each discharge cell while extending in a direction crossing the address electrode, and an enlarged electrode extending from the bus electrode toward the center of each discharge cell. Plasma display panel. The method of claim 11, And the third and fourth electrodes are disposed at positions overlapping the bus electrodes of the first and second electrodes, respectively, when viewed from the front of the panel.

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