JP3772747B2 - Plasma display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma display apparatus known as a display device.
[0002]
[Prior art]
In recent years, expectations for large screens and wall-mounted televisions as interactive information terminals have increased. There are many display devices for this purpose, such as liquid crystal display panels, field emission displays, electroluminescence displays, etc., some of which are commercially available and some are under development. Among these display devices, the plasma display panel (hereinafter referred to as PDP) is a self-luminous type capable of displaying beautiful images and is easy to enlarge. For this reason, a display using PDP has excellent visibility. It is attracting attention as a thin display device, and high definition and large screen are being promoted.
[0003]
This PDP is broadly divided into AC type and DC type in terms of driving, and there are two types of discharge types, a surface discharge type and a counter discharge type. From the viewpoint of high definition, large screen, and ease of manufacturing. At present, AC type and surface discharge type PDPs are becoming mainstream.
[0004]
FIG. 8 shows an example of the panel structure of the PDP. As shown in FIG. 8, the PDP is composed of a front panel 1 and a back panel 2.
[0005]
The front panel 1 includes a plurality of stripe-shaped display electrodes 6 that are paired with a scanning electrode 4 and a sustaining electrode 5 on a transparent front substrate 3 such as a glass substrate made of sodium borosilicate glass or the like by a float method. The dielectric layer 7 is formed so as to cover the display electrode 6 group, and a protective film 8 made of MgO is formed on the dielectric layer 7. Scan electrode 4 and sustain electrode 5 are composed of transparent electrodes 4a and 5a and bus electrodes 4b and 5b made of Cr / Cu / Cr or Ag and the like electrically connected to transparent electrodes 4a and 5a, respectively. ing. Although not shown, a plurality of black stripes as light shielding films are formed between the display electrodes 6 in parallel with the display electrodes 6.
[0006]
In addition, the rear panel 2 forms an address electrode 10 in a direction orthogonal to the display electrode 6 on the rear substrate 9 opposed to the front substrate 3 so as to cover the address electrode 10. A dielectric layer 11 is formed, and a plurality of stripe-shaped partition walls 12 are formed in parallel with the address electrodes 10 on the dielectric layer 11 between the address electrodes 10, and the side surfaces between the partition walls 12 and the dielectric layer 11 The phosphor layer 13 is formed on the surface. For color display, the phosphor layer 13 is usually arranged in order of three colors of red, green, and blue.
[0007]
The front panel 1 and the rear panel 2 are arranged so that the substrates 3 and 9 are opposed to each other with a minute discharge space so that the display electrodes 6 and the address electrodes 10 are orthogonal to each other, and the periphery is a sealing member. And a discharge gas obtained by mixing neon and xenon in the discharge space is sealed at a pressure of about 66500 Pa (500 Torr) to form a panel.
[0008]
The discharge space of the panel is partitioned into a plurality of sections by the partition walls 12, and the display electrodes 6 are provided so that a plurality of discharge cells serving as light emitting pixel regions are formed between the partition walls 12. 6 and the address electrode 10 are arranged orthogonally.
[0009]
That is, as shown in FIG. 9, the display electrode 6 is formed by arranging the scan electrode 4 and the sustain electrode 5 with the discharge gap 14 interposed therebetween, and a region surrounded by the display electrode 6 and the partition 12 is a light emitting pixel. A region 15 is formed, and a non-light emitting region 16 is formed between the display electrodes 6 of the adjacent discharge cells.
[0010]
In this PDP, an image is displayed by generating a discharge by a periodic voltage applied to the address electrode and the display electrode, and irradiating the phosphor layer with the ultraviolet light by the discharge to convert it into visible light.
[0011]
[Problems to be solved by the invention]
For the development of this PDP, further higher brightness, higher efficiency, lower power consumption, and lower cost are indispensable. In order to achieve high efficiency, it is necessary to control the discharge and suppress the discharge in the shielded portion as much as possible. As one of methods for improving the efficiency, a method is known in which the thickness of the dielectric layer on the bus electrode of the display electrode is increased to suppress light emission in a portion shielded by the bus electrode.
[0012]
However, in the conventional structure described above, since the thickened portion of the dielectric layer is only on the bus electrode, the discharge spreads in the direction parallel to the bus electrode, and the discharge reaches near the partition where the electron temperature decreases. And the efficiency decreases. Further, since the thickened portions of the partition of the rear substrate and the dielectric layer of the front panel come into contact with each other and a gap is formed, erroneous discharge in a direction parallel to the electrodes may occur, and the image quality may be deteriorated.
[0013]
Further, in the conventional technique, since the discharge is concentrated in the discharge gap, the luminance saturation of the phosphor in the vicinity tends to occur and the efficiency is lowered.
[0014]
In order to improve the efficiency of such a PDP, as shown in FIG. 9, it is necessary to narrow the non-light emitting region 16 between adjacent discharge cells, widen the display electrode 6 on the discharge gap 14 side, and widen the spread of discharge. However, in this case, since erroneous discharge with adjacent cells increases, it is necessary to narrow the non-light-emitting region 16 between adjacent cells, widen the width of the display electrode 6 and widen the discharge. It has been difficult to achieve both.
[0015]
The present invention has been made to solve these problems, and aims to improve luminous efficiency and image quality.
[0016]
[Means for Solving the Problems]
In order to achieve this object, the present invention forms a recess on the surface of the dielectric layer on the discharge space side so that there are at least two for each discharge cell, and connects the recess for each discharge cell. At least one groove is formed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
That is, according to the first aspect of the present invention, there is provided a discharge cell between a pair of front and back substrates disposed opposite to each other so as to form a discharge space partitioned by a barrier between the substrates, and the barrier. A plurality of display electrodes formed on the front substrate so as to be formed, a dielectric layer formed on the front substrate so as to cover the display electrodes, and discharge between the display electrodes And forming a recess on the surface of the dielectric layer on the discharge space side so that there are at least two for each discharge cell, and connecting the recess for each discharge cell. It is characterized in that at least one groove is formed.
[0018]
Hereinafter, a plasma display device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5, the same parts as those shown in FIG.
[0019]
FIG. 1 shows the structure of a concave portion of a discharge cell in a panel of a plasma display device according to the present invention . In FIG. 1, 21 is a dielectric layer formed on a substrate 3 on the front side so as to cover a display electrode 6, On the surface of the dielectric layer 21 on the discharge space side, recesses 22 are formed so that there are at least two discharge cells for each light emitting pixel region 15. As shown in FIG. 1, the recesses 22 are arranged in parallel to the bus electrodes 4 b and 5 b and the inner part of the partition wall 12 in a direction orthogonal to the display electrode 6, that is, a direction parallel to the partition wall 12. In this way, it is separated into islands. The recess 22 has a rectangular parallelepiped shape and is formed to have a depth of 20 μm.
[0020]
By the way, in order to achieve high efficiency of the PDP, it is indispensable to control discharge in each light emitting pixel region. In particular, in the spread of the discharge in the direction perpendicular to the display electrode, the bus electrode blocks the light emitted from the phosphor layer, so that it is necessary to suppress the discharge from spreading to the shielded portion. In addition, since there is no partition wall in this direction, ultraviolet rays leaking from the barrier rib and light emitted from the phosphor layer are all shielded by the black stripe. Furthermore, the spread of the discharge in the direction parallel to the display electrode causes a decrease in efficiency due to a decrease in the electron temperature in the vicinity of the barrier ribs.
[0021]
In the present invention, a recess 22 is formed on the surface of the dielectric layer 21 on the discharge space side so that there are at least two discharge cells for each light emitting pixel region, as shown in FIG. Since the capacity of the bottom surface of the concave portion 22 with the thin dielectric layer 21 becomes large, charges for discharge are concentrated on the bottom surface of the concave portion 22 as shown in FIG. The discharge area can be limited. On the other hand, in FIG. 3 having a structure without the recess 22, since the film thickness of the dielectric layer 21 is constant, the capacitance is constant on the surface of the dielectric layer, and the discharge is performed as shown in FIG. It spreads in the vicinity of the electrode, and the phosphor in the shielded portion emits light, and the efficiency is lowered. In addition, since charges are formed up to the portion close to the adjacent cell, erroneous discharge with the adjacent cell is likely to occur.
[0022]
As one of the techniques for preventing this and improving the efficiency, for example, as shown in FIG. 4, there is a method of increasing the dielectric film thickness on the bus electrodes 4b and 5b and suppressing the light emission of the portion masked by the bus electrodes. Are known. However, in this method, since the spread of the discharge is narrowed as shown in FIG. 4C, the probability of exciting the discharge gas Xe is lowered, which may cause a reduction in efficiency. In other words, the reason why ITO transparent electrodes are used in a general PDP is to drive the discharge to spread alternately across the sustain electrodes and the scan electrodes by alternately changing the voltages of the sustain electrodes and the scan electrodes. In the configuration as shown in FIG. 4, since the discharge concentrates on the thinned portion of the dielectric layer and the discharge distance cannot be obtained, the probability of Xe excitation is reduced. And the efficiency decreases. Further, in this structure, since the discharge cannot be controlled with respect to the barrier ribs, the discharge spreads to the vicinity of the barrier ribs, and the efficiency of the discharge decreases due to a decrease in the electron temperature there.
[0023]
On the other hand, in the present invention, for example, by forming two recesses 22 with the discharge gap 14 sandwiched as shown in FIG. 2, the discharge gap 14 is changed from the bottom surface of the recess 22 as shown in FIG. Discharging over the projecting portion sandwiches and extends the discharge distance. Therefore, the probability that Xe in the Ne / Xe gas is excited increases, and both discharge control and high efficiency can be achieved. Furthermore, also in the direction of the barrier ribs, it is possible to prevent a decrease in the electron temperature by separating the spread of the discharge from the barrier ribs, so that the discharge can be performed in an ideal state, and the efficiency can be improved.
[0024]
Further, when the film thickness of the dielectric is constant as in the prior art, the discharge is generated from the center of the discharge cell, and the intensity there is the strongest. For this reason, there is a problem that the luminance saturation of the phosphor in the center of the discharge cell is likely to occur and the efficiency is lowered. However, according to the present invention, discharge occurs only at the bottom surface of the recess as described above, Discharge positions can be dispersed from the cell center.
[0025]
Furthermore, in the PDP, in order to increase the light extraction efficiency from the phosphor, that is, to increase the aperture ratio of the discharge cell, the bus electrode is separated from the light emitting region as much as possible. As the distance to the display electrode becomes narrow, the movement of charge between adjacent discharge cells easily occurs, and discharge cells that do not want to emit light emit so-called crosstalk, which causes a problem that the display quality is significantly reduced. To do. In the present invention, the position where many wall charges are generated can be controlled by adjusting the shape of the recess 22 and the place where the recess 22 is formed, thereby preventing the occurrence of crosstalk between adjacent discharge cells. be able to.
[0026]
In the example shown in FIG. 5, the concave portion 22 formed in the dielectric layer 21 is formed in a direction parallel to the display electrode 6, that is, perpendicular to the partition wall 12, on the inner side of the bus electrodes 4 b and 5 b and the partition wall 12. It is formed by separating into islands so as to be arranged in parallel.
[0027]
In the present invention, as shown in FIGS. 6 and 7 , at least one groove 23 is formed so as to connect the recess 22 for each discharge cell. The examples shown in FIGS. 6 and 7 are examples corresponding to FIGS. 1 and 5, respectively.
[0028]
In this way, by forming at least one groove 23 so as to connect the recesses 22 for each discharge cell, a discharge can be generated from that portion, and it can have a role as a seed of discharge. Thereby, a discharge voltage can be reduced and efficiency can be improved.
[0029]
As described above, in the present invention, since the shape can be controlled in various ways depending on the shape of the recess 22, the shape of the recess 22 may be a shape such as a cylinder, a cone, a triangular prism, or a triangular pyramid in addition to the above shape, and is limited to the above embodiment. It is not a thing.
[0030]
【The invention's effect】
As described above, according to the plasma display device of the present invention, the surface of the dielectric layer on the discharge space side is formed with recesses so that there are at least two discharge cells for each light emitting pixel region, Since the bottom surface of the concave portion where the thickness of the dielectric layer is thin has a large capacity, the wall charge formed in that portion is larger than in other portions, and the discharge start voltage decreases due to the decrease in the thickness. The discharge is mainly generated at the bottom surface of the recess, whereby the discharge spreading in the horizontal and vertical directions on the display electrode can be suppressed, and the efficiency can be improved. In addition, by forming the two recesses, the luminance saturation of the phosphor layer located at the center of the light emitting pixel region that is most strongly exposed to the ultraviolet rays generated by the discharge can be reduced, and the phosphor can be used effectively. Can do.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a structure of a concave portion of a discharge cell in a panel of a plasma display device according to the present invention . FIG. 2 is a schematic configuration diagram for explaining the effect of the plasma display device. schematic block diagram for explaining the state of discharge of the device Figure 4 of another conventional plasma display apparatus according to a plasma display schematic diagram for explaining the state of discharge of the apparatus the present invention; FIG panels discharge FIG. 6 is a perspective view showing the structure of another example of the concave portion of the cell . FIG. 6 is a perspective view showing the structure of the discharge cell portion of the panel of the plasma display device according to the embodiment of the invention. The perspective view which shows the structure of the discharge cell part of the panel of the plasma display apparatus by embodiment. FIG. 8 The panel structure of a general plasma display apparatus Plan view showing a structure of a discharge cell part of the perspective view FIG. 9 the plasma display apparatus shown EXPLANATION OF REFERENCE NUMERALS
DESCRIPTION OF SYMBOLS 1 Front panel 2 Back panel 3, 9 Board | substrate 4 Scan electrode 5 Sustain electrode 6 Display electrode 10 Address electrode 12 Partition 13 Phosphor layer 21 Dielectric layer 22 Recessed part 23 Groove

Claims (1)

A pair of front and back substrates disposed opposite to each other so as to form a discharge space partitioned by barrier ribs between the substrates, and arranged on the front substrate so that discharge cells are formed between the barrier ribs. A plurality of display electrodes, a dielectric layer formed on a front substrate so as to cover the display electrodes, and a phosphor layer that emits light by discharge between the display electrodes, and the dielectric A plasma display device in which a recess is formed on the surface of the layer on the discharge space side so that there are at least two for each discharge cell, and at least one groove is formed so as to connect the recess for each discharge cell .

Images