JPH11176337A - Panel structure of plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand a common region by shifting a normal operating voltage range for a selected phosphor, by differentiating a display cell structure for every color. SOLUTION: A width of an address electrode 29b for a phosphor 32b corresponding to the second color with a higher discharge starting voltage is made wider than address electrodes 29a, 29c corresponding to the first and third colors. The phosphor has a shape of a curve of the second order, a discharge starting passage can be considered to be along a line of electric force that starts from a neighborhood of the minimum value of the curve of the second order and reaches a surface of MgO film 27, and the discharge starts when its length and a potential difference between its both ends crosses a Paschen curve. When the width of the address electrode is widened, in comparison with the case where it is kept narrow, 38h for example among equal potential surfaces 38a-38i is expanded toward discharging space and a potential difference between both ends of the line of electric force is made big without changing the distance between both ends. Accordingly, an applied voltage to start discharge can be lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel used for a display device such as a personal computer or a workstation, a flat-type wall-mounted television, a display device for advertisement, information, and the like. Panel structure.

[0002]

2. Description of the Related Art A plasma display has X, Y electrodes arranged parallel to a front glass plate, and address electrodes arranged perpendicularly to the X, Y electrodes on a rear plate via a discharge space. For display, first, a reset discharge is performed to initialize everything equally, and then an address discharge for cell selection is generated between the Y electrode and the address electrode.
Then, a sustain discharge pulse is applied to the two electrode pairs X and Y on the front plate to perform a sustain discharge on the entire surface at the same time. Light emission occurs when the phosphor applied to each cell is excited by ultraviolet rays generated at the time of discharge.

Display of gradation is one field (one screen)
Is divided into a plurality of sub-fields on the time axis, each of which has a different number of discharges in order to change the luminance, and the sub-fields are appropriately combined.

[0004] In the plasma display, one pixel is constituted by light emission by phosphors of three colors of R, G and B. Because of the simplicity of manufacture, panels are often made without distinction by color in terms of structure. At this time, the applied voltage range for normal emission differs depending on which phosphor is used for each color. Until now, no matter which phosphor is selected, a common operating voltage region can be selected by taking a common region of each applied voltage range, and there is no problem in display.

However, in recent years, with the development of drive technology, drive for realizing high-quality display for increasing contrast has become mainstream. In this case, a drive is performed such that the reset discharge is performed only in the cell in which the sustain discharge has been performed in the previous subfield, and not performed in the other cells. Therefore, black can be displayed as it is, and the contrast is improved. At this time, the wall charge distribution situation is different between the cell that performs reset and the cell that does not perform reset. It is getting smaller.

[0006]

In such a prior art, when a common region of a normal operating voltage range of each color is taken, depending on the selection of the phosphor, there is a case in which a reset discharge is performed for all cells. In comparison, the area is narrowed, and in some cases, a common area does not exist, and a situation in which a normal display cannot be performed has become more frequent. Therefore, it has been an urgent task to shift the normal operating voltage range of the selected phosphor to expand the common area.

[0007]

The width of the address electrode is increased for a phosphor having a high discharge starting voltage. As a result, the potential distribution in the discharge cell changes, and the potential difference between both ends of electric lines of force that causes a discharge from the phosphor surface to the MgO film on the front plate sustaining electrode surface can be increased. The voltage can be reduced.

In addition, the coating thickness of the phosphor having a high discharge starting voltage is reduced. As a result, similarly to the above, the potential difference between both ends of the line of electric force which causes a discharge from the phosphor surface to the MgO film on the front plate sustaining electrode surface can be increased, and the discharge starting voltage can be reduced.

Before applying a phosphor having a low discharge starting voltage, another dielectric is applied. For the same reason as above, it is possible to equalize the discharge starting voltage that varies among the phosphors.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

First, FIGS. 2 to 7 show the structure, configuration and driving method of a general plasma display panel. FIG. 2 is an exploded perspective view showing a part of the structure of a general plasma display panel. On the lower surface of the front glass substrate 21, a transparent X electrode 22 and a transparent Y electrode 23 are provided. Each of the electrodes has an X bus electrode 24 and a Y bus electrode 2.
5 are stacked. Further, a dielectric 26 and a protective layer 27 such as MgO are provided on the lower surface.

On the other hand, an address A electrode 29 is provided on the upper surface of the rear glass substrate 28 in a direction perpendicular to the X electrodes 22 and the Y electrodes 23 of the front glass substrate 21. The address A electrode 29 is covered with a dielectric 30, and the partition 3
1 is provided in parallel with the address A electrode 29. Further, a phosphor 32 is applied to the dielectric 30 on the partition 31 and the address A electrode 29.

FIG. 3 is a sectional view of one cell of the plasma display panel viewed from the direction of arrow A in FIG. The address A electrode 29 is located in the middle of the partition 31. Further, a space 33 between the front glass substrate 21 and the rear glass substrate 28
Is filled with a discharge gas such as Ne or Xe.

FIG. 4 is a cross-sectional view of three cells of the plasma display panel viewed from the direction of arrow B in FIG. The boundary of one cell is a position indicated by a substantially dotted line, and the X electrode 22 and the Y electrode
The electrodes 23 are alternately arranged. In the AC type plasma display panel, positive and negative charges are separately collected on the dielectric near the X electrode 22 and the Y electrode 23, and an electric field for discharging is formed using the charges.

FIG. 5 is a schematic diagram showing the wiring and circuit configuration of the X electrode 22, Y electrode 23 and address A electrode 29. X
The drive circuit 34 generates a drive pulse applied to the X electrode 22. The Y drive circuit 35 is connected to each of the Y electrodes 23 and generates a drive pulse to be applied to the Y electrode 23. The A drive circuit 36 is connected to each of the address A electrodes 29 and generates a drive pulse to be applied to the address A electrodes 29.

FIG. 6 shows a field configuration. 4
0 indicates one field period, the horizontal axis indicates time t (one field period), and the vertical axis indicates cell row y. In this case, one field is divided into first to eighth subfields 41 to 48. First subfield 4
First, a first reset period 4 in which discharge and charged particle separation for writing and reducing charged particles are performed in all cells.
1a. At the beginning of the second to eighth subfields 42 to 48, only the cells in which the sustain discharge has been performed in the immediately preceding subfield are selectively reset for writing and discharging for reducing charged particles and for separating charged particles. 42a-4
8a.

After the first and second reset periods, each address period 41b-48b and sustain discharge period 41c-48.
There is c. In the sustain discharge periods 41c to 48c, the number of discharges is assigned to each of the sustain discharge periods 41c to 48c. The number of discharges and the order of subfields are arbitrary, and the present embodiment shows an example in which the discharges are arranged in ascending order.

In order to cause each cell to perform sustain discharge, as shown in FIG.
In this case, it is necessary to cause an address discharge to be performed between the display device 3 and the display of MgO 27 corresponding to the Y electrode in advance with wall charges. However, at present, the discharge starting voltage of the address discharge slightly varies depending on the color. For example, it is known that P1G1S used as a green phosphor is about 15 V larger than other phosphors.

Therefore, as shown in FIG. 8, the applied voltage ranges 50, 51, and 52 for normal emission in each color are slightly different from each other. Here, the applied voltage range in which normal driving can be performed is on the inside of each U-shaped curve. This curve is called the operating margin for each color. To operate normally as a panel,
It is necessary to drive in a common area with the three curves. Therefore, the area becomes an operation margin of the panel. This operation margin differs depending on the drive waveform.

In recent years, for the purpose of improving contrast, so-called high-contrast driving, in which reset discharge is performed only on cells in which sustain discharge has been performed in the preceding subfield without performing reset discharge on the entire surface, has become mainstream. At this time, the charge distribution in the cell is slightly different between the cell that has performed the reset discharge and the cell that does not perform any operation.Therefore, in some cells, the address discharge is weak, and in others, the address discharge is too strong. The range of operation performed during the operation tends to be narrowed.

Accordingly, the operation margin of FIG. 8 tends to be narrower in both the horizontal and vertical directions for each color, and in some cases, a common margin cannot be obtained.

In order to obtain a common margin, the discharge starting voltages of the respective colors may be set in the same region.
In FIG. 8, it is necessary to bring the 50 curves having the highest discharge start voltage to the left.

FIGS. 1A and 1B show an embodiment of the present invention. In the present embodiment, as an example of changing the structure of each cell, the width of the address electrode 29b corresponding to the phosphor 32b having a high firing voltage is changed by changing the width of the other address electrodes 29a, 29c.
It is thicker than that. In the plasma display, a region on the right side of the minimum value of the Paschen curve shown in FIG. 9 is used. Here, p indicates the gas pressure, and d indicates the length of the discharge path. Therefore, when the gas pressure is constant and the discharge path is constant, if the potential difference between both ends of the path can be increased, the applied voltage that can start the discharge can be reduced.

The phosphor usually has a quadratic curve or a shape similar thereto as shown in FIG. The path where the discharge starts can be considered to be along the line of electric force 39 reaching from the vicinity of the minimum value of the quadratic curve to reach the surface of the MgO 27. If the length and the potential difference between both ends cross the Paschen curve, Discharge starts. In the case where the width of the address electrode 29b is made large, as compared with the lower figure in which the address electrode 29b remains narrow, for example, 38h among the equipotential surfaces 38a to 38i showing the same electric potential.
Spread to the discharge space, and the potential difference between both ends is increased without changing the distance between both ends of the electric force line 39. Therefore, the applied voltage for starting the discharge can be reduced.

FIG. 10 shows the calculated potential difference between both ends of the electric flux lines when the address electrode width is changed. 10 μm
The potential difference increases by about 3 V as the thickness increases. In actual driving, it is necessary to reduce the difference in voltage margin between the phosphors to about 5 V, but this can be sufficiently realized by adjusting the width of the address electrode. In the case of driving at the same address voltage, the lower the discharge start voltage of the corresponding phosphor is, the shorter the discharge start time is, and a stable discharge can be obtained. In the malfunction, the discharge does not start within the time when the voltage is applied at the time of addressing, so that the display often fails. Therefore, in that sense, it is effective to lower the discharge starting voltage.

FIG. 11 shows another embodiment of the present invention. In the case of the same structure, when the discharge starting voltage at the time of addressing the middle phosphor 32b is high, the thickness of only the phosphor is reduced. At this time, when the length of the electric force line 39 in the gas space and the potential difference between both ends are plotted, the length becomes longer and the potential difference becomes larger as shown in FIG. This slope is greater than the slope on the right side of the Paschen curve. In other words, the effect of increasing the potential difference is greater than the disadvantage of longer, and when the same voltage is applied to the address electrode 29b, the discharge starting voltage can be reduced.

FIG. 13 shows another embodiment of the present invention. In this case, another dielectric 37 having a high dielectric constant is applied before applying the phosphors 32a and 32c having a low discharge starting voltage. As a result, the distance between the phosphor surfaces 32a and 32c and the surface of MgO 27 is shortened, and even if the discharge starting voltage increases, it can be matched with that of the phosphor 32b having the originally high discharge starting voltage.

Since the discharge starting voltage can be adjusted for each phosphor in this manner, the operation margin can be shifted to the same region. Therefore, it is possible to expand a common operable region, and an operation margin as a panel is increased.

[0029]

According to the present invention, the operation margin of each phosphor can be controlled, and therefore, the common operation margin as a panel can be widened. For this reason, malfunctions are reduced, and the display quality of the panel can be improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a plasma display device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a part of the structure of FIG.

FIG. 3 is a cross-sectional view as viewed from the direction of arrow A in FIG.

FIG. 4 is a cross-sectional view as viewed from the direction of arrow B in FIG.

FIG. 5 is a schematic diagram showing a panel electrode and a circuit configuration.

FIG. 6 is a schematic diagram showing a configuration of one field.

FIG. 7 is a diagram showing an address discharge.

FIG. 8 is a characteristic diagram showing a normal operating voltage range for each color.

FIG. 9 is a characteristic diagram showing a Paschen curve.

FIG. 10 is a characteristic diagram in which the potential difference between both ends of the electric force lines when the address electrode width is changed is plotted.

FIG. 11 is a side sectional view of another embodiment of the present invention, in which the coating thickness of a phosphor having a high firing voltage is reduced.

FIG. 12 is a characteristic diagram in which the length of electric lines of force in the gas space where discharge starts and the potential difference between both ends are plotted when the thickness of the phosphor is changed.

FIG. 13 is a view showing another embodiment of the present invention in which a dielectric is applied before applying a phosphor having a low discharge start voltage, and the discharge start voltage is increased.

[Explanation of symbols]

Reference numeral 21: front glass substrate, 22: X transparent electrode, 23: Y transparent electrode, 24: X bus electrode, 25: Y bus electrode, 26,
Reference numerals 30, 37: dielectric, 27: MgO film, 28: rear glass substrate, 29: address A electrode, 29a: address electrode corresponding to the first color, 29b: address electrode corresponding to the second color, 29c ... Address electrodes corresponding to the third color,
31 ... partition wall, 32 ... phosphor, 32a ... phosphor corresponding to the first color, 32b ... phosphor corresponding to the second color, 32c
... a phosphor corresponding to the third color, 33 ... discharge space, 34 ...
X drive circuit, 35 ... Y drive circuit, 36 ... A drive circuit, 3
8a to 38j: equipotential, surface, 39: lines of electric force, 40: 1
Fields, 41 to 48 ... first to eighth subfields,
41a to 48a: reset period, 41b to 48b: address period, 41c to 48c: sustain discharge period, 50: first
, The normal operating voltage range for the second color, the normal operating voltage range for the third color, and the address discharge.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Sasaki 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the new display business promotion center of Hitachi, Ltd. No. 1-1 Inside Hitachi, Ltd. Hitachi Research Laboratories (72) Inventor Keizo Suzuki 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside New Display Business Promotion Center of Hitachi, Ltd. 1-280 Higashi Koigakubo, Kokubunji City Hitachi Central Research Laboratory, Ltd.

Claims (3)

[Claims] 1. A plasma display comprising: a plurality of display cells; a unit for generating plasma in the display cell; and a unit for generating visible light using ultraviolet light generated by the plasma, wherein the plasma , A discharge gas for generating the plasma, and an electrode for generating the plasma, and the display cells are repeatedly coated with RGB phosphors for color display over the entire panel. In the plasma display panel according to the present invention, the structure of the display cell is different for each color. 2. A panel according to claim 1, wherein the line width of said third electrode group is different for each of R, G and B. Construction. 3. The panel structure of a plasma display panel according to claim 1, wherein the thickness of the applied phosphor is:
A panel structure of a plasma display panel, wherein R, G, and B are different from each other.