KR100562861B1 - 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 improvement of image sticking of a local discharge region generated by local discharge in an AC surface discharge plasma display panel.

A pair of discharge sustaining electrodes formed on opposite surfaces of said front substrate, bus electrodes formed on each of said discharge sustaining electrodes, dielectric layers covering said discharge sustaining electrodes and bus electrodes, said dielectric material A plasma display panel comprising a protective film coated on a layer, an address electrode formed on an opposite surface of the rear substrate, a dielectric layer covering the address electrode, a partition formed on the dielectric layer, and a fluorescent layer applied in a region partitioned by the partition wall. And a fluorescent layer using a classification phosphor having a substantially uniform particle size of red, green, and blue phosphors on the reflecting plate and the reflecting plate of titanium trioxide (TiO ₃ ) applied in the partitioned area. Include.

Plasma display panel, titanium trioxide, phosphor, afterimage, luminance

Description

Plasma Display Panel {Plasma Display Panel}

1 is a structural diagram of a typical AC surface discharge plasma display panel.

2 is an image sticking phenomenon of the plasma display panel.

3 is a cross-sectional view for explaining the principle of an afterimage generated by the influence of a phosphor of a conventional plasma display panel.

4 is a graph showing a luminance change generated when the temperature is stopped after forcibly increasing the temperature to 55 ° C. in full white.

5 is a graph showing a cause of mis-discharge of the plasma display panel.

FIG. 6 is a change in color balance diagram showing a change in color balance by enlarging a change in color coordinates of the blue phosphor shown in FIG. 5; FIG.

FIG. 7 schematically illustrates phosphor emission thickness variation when the phosphor density according to the first embodiment of the present invention is increased.

8 is a schematic diagram showing a return state of a light emitting part of a phosphor to which a phosphor density according to a second embodiment of the present invention is increased and a reflector of titanium trioxide (TiO ₃ ) is applied.

9 is a schematic diagram of increasing the phosphor density according to the third embodiment of the present invention and varying the thickness of the R G B phosphor.

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

301, 302, 303, 701, 702, 703, 801, 802, 803, 901; Phosphor light emitting layer

304, 704, 804, 904; Classification phosphor

305, 705, 805, 905; Address electrode

306, 706, 806, 906; Glass 307, 707, 807; Returned phosphor

310, 710, 810; Luminescence of Phosphor at Early Full White

320, 720, 820; Luminescence of Phosphors During Window Patterns

330, 730, 830; Phosphor emission on full white return

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to improvement of image sticking of a local discharge region generated by local discharge in an AC surface discharge plasma display panel (hereinafter referred to as PDP). .

1 is a structural diagram of a general AC surface discharge plasma display panel.

As illustrated in FIG. 1, a typical AC type surface discharge plasma display panel includes a front substrate 122 and a back substrate 124 made of transparent glass facing each other in parallel with each other at intervals of 100 to 200 μm. At this time, the partition wall 126 is formed in parallel on the rear substrate 124 through a thick film printing technique in order to maintain a distance from the front substrate 122. The distance between these partitions 126 is 400 µm, and the width of each partition 126 is 50 µm.

In addition, a column Xj (j = 1, 2, ..., m) of an X electrode made of aluminum (Al) or an aluminum alloy between the partition walls 126 adjacent to each other is partitioned to a thickness of 100 nm to perform an addressing function. It is formed parallel to. The light emitting layer 136 is formed while the R, G, and B phosphor films cover each X electrode with a thickness of 10 to 30 µm.

On the other hand, the row electrodes Yi and Zi (i = 1, 2, ..., n) of the Y electrode and the Z electrode are formed perpendicular to the X electrode on the surface of the front substrate 122 facing the rear substrate 124. The Y electrode and the Z electrode extend in parallel to each other by a thickness of approximately several hundred nm by deposition of ITO or tin oxide (SnO), and the row electrode Yi and Zi adjacent to each other form a pair of row electrode pairs Yi, Zi).

Further, in each of the row electrodes Yi and Zi, metal bus electrodes? I and? I narrower than the widths of the row electrodes Yi and Zi are formed in close contact with the row electrodes Yi and Zi. These bus electrodes alpha i and beta i are complementary to the row electrodes Yi and Zi having low conductivity as auxiliary electrodes.

In order to protect the row electrodes Yi and Zi, the dielectric layer 130 is formed to a thickness of about 20 to 30 μm. In contact with the dielectric layer 130, an MgO layer 132 made of magnesium oxide (MgO) is laminated to a thickness of approximately several hundred nm.

After the electrodes Xj, Yi, Zi, αi, βi, the dielectric layer 130 and the light emitting layer 136 are formed, the front substrate 122 and the back substrate 124 are sealed and exhaust of the discharge space 128 Then, moisture on the surface of the MgO layer 132 is removed by baking. Subsequently, an inert mixed gas including 3 to 7% of NeXe gas is injected into the discharge space 128 at 400 to 600 torr.

The unit emission region is defined as one pixel cell P _{(i, j)} around the intersection with the Xj electrode intersecting the Yi, Zi electrode. When the wall voltage is formed by the addressing discharge between the Xj electrode and the Yi electrode _{, the} pixel cell P _{(i, j)} is sustained by applying a sustain pulse between the Yi electrode and the Zi electrode, so that the discharge of the phosphor 136 is maintained. The light emission is controlled by selecting, holding and erasing the light emission discharge of the pixel cells P _{(i, j)} by applying voltage between the Xj, Yi and Zi electrodes.

At this time, a sustain pulse is alternately applied to the Yi electrode and the Zi electrode, respectively. That is, if a sustain pulse is applied to the Yi electrode, no sustain pulse is applied to the Zi electrode, and if a sustain pulse is applied to the Zi electrode, the sustain pulse is not applied to the Yi electrode, thereby maintaining surface discharge using alternating current.

As described above, the PDP has a problem of afterimage that a display device using phosphor excitation generally has.

FIG. 2 is a diagram for explaining occurrence of local afterimage occurring in a conventional PDP.

As shown in FIG. 2, when a predetermined window pattern is displayed on the center portion of the screen, the window pattern intensively discharges a portion 200a of the panel display surface 200. Subsequently, when the entire panel 200b is discharged, the window pattern displayed on the portion 200a of the panel display surface 200 appears as an afterimage 200c. The afterimage 200c is further exacerbated by deterioration of the phosphor, surface property change of the protective film, or mis-discharged erase discharge due to unsafe driving of the PDP.

Such an afterimage 200c is generated by a high voltage and a high temperature. That is, a high voltage or high temperature during discharge generates excessive charged particles in the discharge space, and the fluorescent material is deteriorated by the impact of the generated charged particles, leaving an afterimage on the screen.

Since the PDP reproduces colors through the excitation of each of the phosphors in RGB, the emission characteristics of the phosphors are changed by the impedance variation of the panel and the power concentration phenomenon, and the afterimage characteristic depends on how quickly the characteristic changes are returned. . As described above, the PDP depends on the change in the emission characteristics and the return characteristics of the phosphor. In the case of a liquid crystal display (LCD), since the color is reproduced using a color filter while the liquid crystal is turned on and off, the afterimage is Contrast with only being affected by the light emission of the backlight. As such, the afterimage characteristic of the PDP is a major factor deteriorating the characteristics of the PDP in that it is different depending on the type of the phosphor of the R G B. On the other hand, in the case of LCD, since the color balance is adjusted by the color filter, the luminance change rate acts the same with respect to R G B in the process in which an afterimage occurs and disappears, so that there is no change in color coordinate characteristics. In the PDP, since the luminance returns of the R G B phosphors are different from each other, variations in color coordinates occur in the process of remaining after image emission and disappearance.

For example, a product of full white (total 100 cd / m2) having R: 30 cd / m2, G: 60 cd / m2, and B: 10 cd / m2 is R: 60 cd / m2, G: 120 cd / m2 by a window pattern. , When B: 20cd / m2, full white (total: 200cd / m2), and then back to the original, R: 22cd / m2, G: 105cd / m2, B: 13cd / m2 full white (total: 140 cd / m &lt; 2 &gt;), this is represented by a clear luminance afterimage. Therefore, this can be easily solved by reducing the luminance recovery time. However, if it is changed back to full white (total: 94cd / m2) with R: 26cd / m2, G: 59cd / m2, and B: 9cd / m2, the 6cd / m2 difference may not be felt by human vision. In this case, the luminance recovery rates of the R G B phosphors are 86.7%, 98.3%, and 90%, respectively. As a result, the color balance is maintained only when the luminance return ratios are 100%, 100%, and 100%, respectively, and thus, the color balance is largely impaired. Therefore, the problem remains even more serious in that afterimages generated in PDP products are deteriorated in color balance due to different luminance ratios of R G B phosphors.

3 is a cross-sectional view for explaining the principle of the afterimage generated by the influence of the phosphor of the conventional plasma display panel. In general, the influence on the phosphor brightness can be distinguished by the characteristics due to the phosphor self-luminous characteristics and the characteristics due to the shape of the phosphor, and the approach caused by the phosphor self-luminous characteristics is solved by changing the phosphor material. It is possible to do this, and the aspect of shape can be linked to structural issues. As shown, Figure 3 shows the principle approached from the structural point of view of the phosphor.

The phosphor emits light 301 as much as a thickness of a vacuum ultraviolet ray (VUV) generated by the fluorescent light emitting layer 310 when the initial full white is incident (301). The intensity of s becomes stronger so that the phosphor participating thickness 302 of the phosphor becomes larger. In the case of returning from the window pattern to the full white pattern again (330), the phosphor emitting layer 307 participating in the window pattern may not return to the normal state. For example, if the thickness of the vacuum ultraviolet rays generated during the first full white incident on the phosphor is less than 5 μm, the phosphor emits the light at a thickness of about 5 μm. However, when the window pattern is full white, the intensity of the vacuum ultraviolet ray becomes stronger, and when the incident thickness of the vacuum ultraviolet ray rises to about 7 μm, the thickness of the phosphors participating in the phosphor becomes 7 μm. In the case of returning from the window pattern to the full white pattern, the phosphor that participated in the light emission at about 7 μm participates in the light emission only at the thickness of about 5 μm, but the problem is that the phosphor thickness of about 2 μm did not participate. The thickness of the µm phosphor and its properties are not the same. This affects the return of the luminance of the phosphor, which may be deepened depending on physical properties or structural problems.

4 is a graph showing a luminance change generated when the temperature is stopped after forcibly increasing the temperature to 55 ° C. in full white. Fig. 4 shows the luminance of the RGB phosphor and the temperature from when the temperature is cut off (0 minutes) until 30 minutes have elapsed when the applied temperature is cut out after forcibly applying the temperature to 55 ° C. in full white. It is showing a return. As shown in Fig. 4, the luminance of each phosphor is restored from the time point at which the temperature is cut off (0 minutes). However, even after 30 minutes have elapsed, it can be seen that the color balance of the R G B phosphor is not corrected based on the luminance line of the steady state of the R G B phosphor before the temperature rise, which is the cause of the afterimage.

5 is a graph showing color coordinates for explaining the cause of the mis-discharge. As shown in FIG. 5, when looking at the green phosphor, the color coordinate of the green phosphor before temperature application (Rise Temperature; RT) changes to a coordinate system in which the y-axis decreases and the x-axis increases as the temperature decreases. It can be seen that the discharge occurs.

FIG. 6 illustrates a change in color balance by enlarging a change in color coordinates of the blue phosphor illustrated in FIG. 5. FIG. 6 shows the change in the color balance of the blue phosphor in color coordinates when the applied temperature is forcibly applied to 55 ° C. from outside in full white. As shown in FIG. 6, when the temperature is applied at room temperature and then the temperature is cut off, the color coordinates change significantly as time passes immediately after the temperature cutoff. In addition, it can be seen that even after 30 minutes have elapsed, the color coordinates deviate greatly from the color coordinates at room temperature.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma display panel having an improved afterimage problem caused by varying the return ratios of the luminance of R G B due to a rise in temperature during discharge.

The present invention for achieving the above object is a pair of discharge sustaining electrode having a front substrate and a rear substrate facing each other, formed on the opposite surface of the front substrate, a bus electrode formed on each of the discharge sustaining electrode, the A dielectric layer covering a discharge sustain electrode and a bus electrode, a protective film coated on the dielectric layer, an address electrode formed on an opposite surface of the rear substrate, a dielectric layer covering the address electrode, a partition formed on the dielectric layer, and a region partitioned by the partition wall. In a plasma display panel including a coated fluorescent layer, particle sizes of red, green, and blue phosphors are reflected on a reflector and a reflector of titanium trioxide (TiO ₃ ) coated in a partitioned area. Includes a fluorescent layer using a substantially uniform classification phosphor.

Before describing the processing and coating method of the phosphor according to the present invention will be described a general method as follows.

Red phosphor is mainly Y ₂ O ₃ : Eu, (Y, Gd) BO ₈ : Eu, green phosphor is Zn ₂ SiO ₄ : Mn, BaAl ₁₂ O ₉ : Mn, blue phosphor is BaMgAl ₁₀ O ₁₇ : Eu Each is processed by coprecipitation method, Sol-Gel method, coprecipitation method or Flux Aided Solid State Reaction method.

In addition, currently used phosphor coating methods include a screen printing method, a sand blast method, a photolithography method, a battery electrodeposition method, and the like. Among them, the screen printing method and the sand blast method are the most widely used. Process and coating method of the phosphor according to the invention can be made by any one of the above methods.

<First Embodiment>

According to the first embodiment of the present invention, the above-described object can be achieved by increasing the coating density of the phosphor than the conventional one. In this way, in order to increase the coating density of the phosphor than the conventional one, the phosphor having a constant particle size is used in the first embodiment of the present invention.

Currently, the particle size of phosphors is 1 to 5 μm, and phosphors having different particle sizes are gathered, so that the coating density of the phosphor is considerably decreased. Therefore, the present invention is characterized by using a phosphor processed by distinguishing a phosphor having a uniform particle size (that is, a classification phosphor) in order to increase the coating density of the phosphor. For example, only one micrometer having a particle size of 1 μm and only three micrometers having a particle size of 3 μm produce a phosphor. However, it is preferable that a fluorescent substance having a high density according to one embodiment of the present invention uses a classification phosphor whose particle size of the phosphor is 1 μm or less. This is because the use of a phosphor having a particle size of 1 μm or less among the particle sizes of various kinds of phosphors can further increase the density of the phosphor.

FIG. 7 schematically illustrates phosphor emission thickness variation when the phosphor density of the PDP according to the first embodiment of the present invention is increased.

As shown in FIG. 7, the light emitting part layer 710 of the phosphor during initial full white emission emits light 701 as much as the thickness of the generated vacuum ultraviolet rays is incident, and when window pattern in full white 720 is performed. The intensity of the vacuum ultraviolet light is increased so that the light emitting part participation thickness 702 of the phosphor becomes large, but when the particle size of the phosphor returns from the window pattern to the full white pattern again by the uniform classification phosphor 705 (730) The thickness at which the phosphor light emitting layer 707 participating in the pattern does not return to the normal state becomes smaller than the return light emitting layer 307 shown in FIG. 3.

Second Embodiment

According to the second embodiment of the present invention, the afterimage problem can be improved by applying a reflector of titanium trioxide for luminance compensation to increase the density of the phosphor and to compensate for the luminance loss.

An application process of the phosphor and titanium trioxide of the present invention will be described.

By increasing the density of the phosphor, the thickness of the luminescent part of the phosphor due to the vacuum ultraviolet ray is reduced, thereby resulting in luminance loss. In order to compensate for this, the reflector of titanium trioxide is applied for luminance compensation. In the current method of applying a phosphor, a red phosphor is applied by placing a screen mask for applying a red phosphor on a lower plate on which a partition is formed, and then printing and drying the red phosphor. Then, green and blue phosphors are sequentially applied in the same manner as described above. On the other hand, the method for applying titanium trioxide according to the present invention is a well-known technique, which will be briefly described. A screen mask is placed on a lower substrate in which an address electrode, a lower dielectric layer and a partition are sequentially stacked on a lower substrate, and then a predetermined A pressure applied squeeze is used to print the material of titanium trioxide on the bottom plate on which the screen mask is placed. Subsequently, when the screen mask is removed, the titanium trioxide material is applied onto the bottom plate. When the lower plate coated with the titanium trioxide material is dried, a reflector plate of titanium trioxide coated only on the surface of the titanium trioxide partition wall is completed. The phosphor is applied to the phosphor through the phosphor coating method described above.

FIG. 8 schematically shows the return state of the light emitting part of the phosphor when the reflector of titanium trioxide is applied to compensate for the luminance loss by using a classification phosphor having a uniform particle size distribution shown in FIG. 7. It is. Since a detailed description thereof is the same as that of FIG. 7, it will be omitted below. However, in the second embodiment according to the present invention, the thickness of the phosphor is preferably 10 μm or less.

Third Embodiment

In addition, according to the third embodiment of the present invention, the afterimage problem can be improved by increasing the density of the phosphor and varying the thickness of the R G B phosphor.

It is characterized in that the coating thicknesses of the R G B phosphors are different because the luminance recovery times of the R G B phosphors are different.

Fig. 9 shows that the phosphors are coated in such a way that the phosphor luminance recovery time of R G B is different, so that the thickness of each R G B phosphor is the smallest in the coating thickness of the phosphor having the longest recovery time. That is, the largest thickness of the phosphor is the phosphor having the shortest recovery time after the participation of light emission, and the smallest the thickness of the phosphor is the phosphor having the longest recovery time after the participation of light emission. By doing this, the cause of the afterimage can be eliminated by bringing the return time after the participation of each phosphor to be similar. The thickness of each phosphor may be variously changed and modified by those skilled in the art through the above description without departing from the spirit of the present invention.

According to the present invention, by increasing the density of the phosphor, the variation in the phosphor emission thickness is reduced to increase the luminance recovery rate.

In addition, while increasing the density of the phosphor, by applying a reflector of titanium trioxide for the compensation of the loss of luminance, it eliminates the unnecessary thickness of the phosphor that does not participate in luminescence to lower the thickness of the phosphor, and to reduce the luminance loss. Since afterimages from PDP products can be minimized, product quality can be improved.

In addition, by increasing the density of phosphors, the coating thickness of the phosphors is different for each of R, G, and B phosphors, and the return time after light emission can be similar to minimize afterimages generated in PDP products, thereby improving product quality. have.

Claims (5)

A pair of discharge sustaining electrodes formed on opposite surfaces of said front substrate, bus electrodes formed on each of said discharge sustaining electrodes, dielectric layers covering said discharge sustaining electrodes and bus electrodes, said dielectric material A plasma display panel comprising a protective film coated on a layer, an address electrode formed on an opposite surface of the rear substrate, a dielectric layer covering the address electrode, a partition formed on the dielectric layer, and a fluorescent layer applied in a region partitioned by the partition wall. , A reflector plate of titanium trioxide (TiO ₃ ) coated in the partitioned region; Phosphor layer using classification phosphor having substantially uniform particle size of red, green, and blue phosphors on the reflecting plate Plasma display panel comprising a. delete delete The method of claim 1, And a red, green, and blue phosphor applied in the area partitioned by the partition wall has a different thickness. The method according to claim 1 or 4, And a classification phosphor having a particle size of red, green, and blue phosphors applied in the partitioned area of the partition wall to be 1 µm or less.

Images