JP2008218434A - Plasma display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve luminous efficiency and to stabilize panel drive, in a plasma display device. <P>SOLUTION: The plasma display device has: a plurality of display electrodes formed on a front substrate by being arranged to face through a discharge gap on a display line basis and comprising discharge electrodes 18a and bus electrodes 18b for feeding power to the discharge electrodes 18a; a dielectric layer formed on the front substrate to cover the display electrodes; and a phosphor layer emitting light by discharge between the display electrodes. On a discharge space-side surface of the dielectric layer for every discharge cell, at least two recessed parts 17a and 17b are formed for the discharge gap 14, and the discharge electrodes 18a of the display electrodes are formed by being projected from the bus electrodes 18b vertically to the discharge gap 14 to be opposed through the discharge gap 14 on bottom surfaces of the recessed parts 17a and 17b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma display apparatus known as a display device.

  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.

  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.

  FIG. 10 shows an example of the panel structure of the PDP. As shown in FIG. 10, the PDP is composed of a front panel 1 and a back panel 2.

  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 transparent electrodes 4a and 5a serving as discharge electrodes, and bus electrodes 4b and 5b made of Cr / Cu / Cr, Ag, or the like electrically connected to transparent electrodes 4a and 5a, respectively. It consists of and.

  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.

  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 Ne and Xe in the discharge space is sealed at a pressure of about 66500 Pa (500 Torr) to form a panel.

  The discharge space of the panel is divided into a plurality of sections by the barrier ribs 12, and a display electrode 4 is provided between the barrier ribs 12 so that a plurality of discharge cells serving as unit light emitting regions are formed. 6 and the address electrode 10 are arranged orthogonally.

  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.

  As shown in FIG. 11, the scan electrodes 4 and the sustain electrodes 5 are alternately arranged in the column direction so as to be adjacent to each other with the discharge gap 14 in each line A of the matrix display. Here, a region surrounded by the partition wall 12, the pair of scan electrodes 4, and the sustain electrode 5 is a unit light emitting region 15. Further, since the non-light emitting region is 16, black stripes may be formed for the purpose of improving contrast.

  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 at 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.

  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 back 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.

  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.

  Furthermore, to improve the efficiency, it is necessary to narrow the non-light emitting region 16 with the adjacent cell and widen the electrode on the discharge gap side to widen the discharge as shown in FIG. Since the number of erroneous discharges increases, it has been impossible to achieve both the narrowing of the non-light emitting area with the adjacent cell and the widening of the electrode width and the spread of the discharge in the horizontal direction.

  The present invention has been made to solve such problems, and aims to improve luminous efficiency and stabilize panel driving.

  In order to achieve this object, the present invention provides at least two recesses with respect to the discharge gap on the surface of each discharge cell on the discharge space side of the dielectric layer, and the discharge electrode of the display electrode is formed as described above. It is characterized in that it is formed so as to protrude vertically from the bus electrode toward the discharge gap so as to face each other through the discharge gap at the bottom surface of the recess.

  According to the plasma display device of the present invention, the discharge can be controlled, the driving in the address period can be stabilized, and the improvement in efficiency due to the high Xe partial pressure can be effectively utilized. The improvement of the efficiency and the improvement of the image quality can be achieved.

  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 displays comprising a discharge electrode and a bus electrode for supplying power to the discharge electrode and arranged on the front substrate so as to face each other via a discharge gap on the front substrate. An electrode, a dielectric layer formed on the substrate on the front side so as to cover the display electrode, and a phosphor layer that emits light by discharge between the display electrodes, the discharge layer side of the dielectric layer At least two recesses are formed on the surface of each discharge cell with respect to the discharge gap, and the discharge electrode of the display electrode is perpendicular to the bus electrode so as to face the bottom surface of the recess via the discharge gap. It is characterized in that it has formed to protrude toward.

  The invention described in claim 2 is characterized in that, in claim 1, the discharge electrode is a transparent electrode.

  According to a third aspect of the present invention, in the first aspect, the discharge electrode is configured such that the width of the portion opposed to the bottom surface of the concave portion via the discharge gap is equal to or smaller than the width of the concave portion. It is characterized by that.

  According to a fourth aspect of the present invention, in the first aspect, the discharge electrode has a shape in which a portion opposed to the bottom surface of the recess through the discharge gap is divided into a plurality of portions.

  The invention according to claim 5 is characterized in that, in claim 1, the discharge electrode has a hollow middle portion.

  According to a sixth aspect of the present invention, in the first aspect, at least one groove is formed so as to connect the concave portions for each discharge cell.

  The invention described in claim 7 is characterized in that, in claim 1-6, a mixed gas of Ne and Xe is enclosed in the discharge space, and the Xe partial pressure is 5-30%.

  Hereinafter, a plasma display device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9, the same parts as those shown in FIGS. 10 and 11 are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 1 is a perspective view of a part of a front panel of a plasma display device according to an embodiment of the present invention. In the figure, a dielectric layer 7 formed on a substrate 3 on the front side so as to cover display electrodes. On the surface on the discharge space side, two recesses 17a and 17b are formed for each discharge cell. FIG. 2 shows the positional relationship between the recesses 17a and 17b and the display electrodes and the partition walls 12. As shown in FIG. 2, the recesses 17a and 17b are formed inside the partition walls 12. .

  The display electrode is composed of a discharge electrode 18a made of a transparent electrode arranged so as to face each other via a discharge gap for each display line, and a bus electrode 18b for supplying power to the discharge electrode 18a. The discharge electrode 18a of the display electrode is formed so as to protrude vertically from the bus electrode 18b toward the discharge gap 14 so as to face each other via the discharge gap 14 on the bottom surfaces of the recesses 17a and 17b. The discharge electrode 18a is configured such that the width of the part facing the discharge gap 14 on the bottom surface of the recesses 17a and 17b is equal to the width of the recesses 17a and 17b or narrower than the width of the recesses 17a and 17b. In the example shown in FIG. 2, the width of the portion of the discharge electrode 18a that faces the discharge gap 14 is narrower than the width of the recesses 17a and 17b.

  Here, in order to achieve high efficiency of the PDP, it is essential to control the discharge in each light emitting pixel region. In particular, in the spread of the discharge perpendicular to the electrode, the bus electrode blocks the light emitted from the phosphor, and therefore it is necessary to suppress the spread of the discharge to the shielded portion. Further, since there is no partition wall in this direction, all the ultraviolet rays and light emitted from the phosphor are shielded by the black stripe. Furthermore, the spread of the discharge in the direction parallel to the electrodes causes a decrease in efficiency due to a decrease in the electron temperature in the vicinity of the barrier ribs.

  FIG. 8 is a diagram for explaining the effect when two concave portions are formed in the dielectric, and FIG. 9 is a diagram for comparison. In FIGS. 8 and 9, A indicates discharge.

  In FIG. 8, since the film thickness of the dielectric on the bottom surfaces of the two recesses 17a and 17b is reduced, the capacitance C at that portion increases. Therefore, electric charges for discharge are concentrated on the bottom surfaces of the recesses 17a and 17b, and the discharge region can be limited. On the other hand, in FIG. 9, since the dielectric film thickness is constant, the capacitance C is constant on the dielectric surface, the discharge A spreads in the vicinity of the electrode, and the phosphor in the shielded portion is caused to emit light. Decreases. 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.

  Further, as one of the techniques for preventing this and improving the efficiency, for example, as described in JP-A-8-250029, the dielectric film thickness on the metal row electrode is increased and masked with the metal row electrode. A method for suppressing light emission of a portion is known. However, in this method, since the spread of the discharge A is narrowed, the probability of exciting Xe is lowered, and the efficiency may be lowered. That is, the reason why ITO is used for the front panel in a general PDP is to drive the discharge to spread alternately across the sustain electrode and the scan electrode by alternately changing the voltage of the sustain electrode and the scan electrode. The device has been designed to spread the discharge. However, in such a method, since the discharge concentrates on the thinned portion of the dielectric and the discharge distance cannot be obtained, the probability of Xe excitation is lowered and the efficiency is lowered. Further, in this structure, since the discharge cannot be controlled with respect to the barrier rib, the discharge spreads to the vicinity of the barrier rib, and the discharge efficiency is lowered due to a decrease in the electron temperature there.

  In the present embodiment, for example, as shown in FIG. 8, by forming two recesses 17a and 17b with the discharge gap interposed therebetween, the portion of discharge A protruding from the bottom surface of the recesses 17a and 17b with the discharge gap 14 interposed therebetween is formed. The discharge distance is extended, and the discharge distance is extended. Therefore, the probability that Xe in the Ne / Xe gas is excited increases, and it is possible to achieve both discharge control and high efficiency. Further, by separating the spread of discharge from the barrier ribs in the barrier rib direction, it is possible to prevent a decrease in the electron temperature, discharge can be performed in an ideal state, and efficiency can be improved.

  Further, the discharge electrode 18a of the display electrode is formed so as to protrude vertically from the bus electrode 18b toward the discharge gap 14 so as to face the bottom surface of the recesses 17a and 17b via the discharge gap 14, and the electrode from the partition wall 12 is formed. By separating, it is possible to suppress the accumulation of electric charges in the vicinity of the partition wall 12 and further to suppress the discharge in the vicinity of the partition wall 12.

  When the discharge electrode 18a is made of a transparent electrode, light emitted from the phosphor can be taken out efficiently.

  On the other hand, when the discharge electrode 18a is made of an opaque metal electrode like the bus electrode 18b, cost reduction can be achieved. In this case, since the light emitted from the phosphor is shielded by the electrodes, as shown in FIG. 3, the discharge electrode 18a has a plurality of portions facing each other through the discharge gap 14 on the bottom surfaces of the recesses 17a and 17b. The efficiency of extracting light emission can be improved by making the middle part hollow as shown in FIG. Further, when such a shape is used for the transparent electrode, an effect of reducing current consumption due to a reduction in electrode area can be obtained.

  Here, in order to achieve high efficiency of the PDP, a method of increasing the Xe partial pressure is generally known. However, when the Xe partial pressure is increased, there arises a problem that the discharge voltage is increased, and an amount of ultraviolet rays is increased, thereby causing a problem of easily causing luminance saturation. For this purpose, a method is known in which the dielectric film thickness is increased, the dielectric capacity is decreased, and the charge formed by a single pulse is reduced. In this case, however, the dielectric film thickness is increased. Accordingly, there arises a problem that the transmittance of the dielectric film itself is lowered and the efficiency is lowered. Further, simply increasing the film thickness causes a problem that the discharge voltage further increases.

  According to the present invention, in a PDP in which a mixed gas of Ne and Xe is sealed in the discharge space and the Xe partial pressure is 5 to 30%, the current is controlled by the shape of the recesses 17a and 17b, so that a high Xe content can be obtained. Luminance saturation caused by pressure can be prevented. That is, the discharge current can be controlled by limiting the discharge area by forming the recesses 17a and 17b having the optimum size in each light emitting pixel area. Further, the amount of current that flows arbitrarily can be limited by changing the shape or size of the recesses 17a and 17b. Furthermore, according to the present embodiment, since the current control is performed only with a dielectric, it is possible to use a high Xe partial pressure without changing a circuit or a driving method.

  5 to 7 show perspective views of a part of a front panel in a plasma display device according to another embodiment of the present invention. First, in the example shown in FIG. 5, at least one groove 19 is formed so as to connect the recesses 17a and 17b for each discharge cell. In this case, both the reduction of the discharge start voltage and the increase of the discharge distance can be achieved. It becomes possible.

  In the example shown in FIG. 6, two recesses 17a and 17b are formed side by side so as to be perpendicular to the bus electrode 18b. In this case, the discharge start voltage can be lowered. Further, in the example shown in FIG. 7, at least one groove 19 is formed so as to connect two concave portions 17a and 17b formed so as to be perpendicular to the bus electrode 18b as shown in FIG.

  In the above description, the example in which the two concave portions 17a and 17b are formed has been described. However, two or more concave portions may be formed, and the shape of the concave portion may be a polygon, a circle, or an ellipse. If it does, it will not be restricted to the said description.

  As described above, according to the plasma display device of the present invention, the discharge can be controlled, the driving in the address period can be stabilized, and the efficiency improvement by the high Xe partial pressure can be effectively utilized. Thus, an improvement in panel efficiency and an improvement in image quality can be achieved. This is very useful industrially.

The perspective view which shows the principal part structure of the plasma display apparatus by one embodiment of this invention The top view which shows the arrangement | positioning relationship of the principal part of the apparatus The top view which shows the arrangement | positioning relationship of the principal part of the plasma display apparatus by other embodiment of this invention. The top view which shows the arrangement | positioning relationship of the principal part structure of the plasma display apparatus by other embodiment of this invention. The perspective view which shows the principal part structure of the plasma display apparatus by other embodiment of this invention. The perspective view which shows the principal part structure of the plasma display apparatus by other embodiment of this invention. The perspective view which shows the principal part structure of the plasma display apparatus by other embodiment of this invention. Schematic for explaining the discharge state of the plasma display device according to the present invention. Schematic for explaining the discharge state of a conventional plasma display device The perspective view which shows the panel structure of a plasma display apparatus The top view which shows the arrangement | positioning relationship of the principal part of a plasma display apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front panel 2 Back panel 3, 9 Board | substrate 4 Scan electrode 5 Sustain electrode 6 Display electrode 7 Dielectric layer 10 Address electrode 12 Partition 13 Phosphor layer 14 Discharge gap 17a, 17b Recessed part 18a Discharge electrode 18b Bus electrode 19 Groove

Claims (1)

A pair of front-side and back-side substrates arranged opposite to each other so as to form a discharge space partitioned by a partition between the substrates, and a display line on the front-side substrate so that a discharge cell is formed between the partitions. A plurality of display electrodes that are formed so as to be opposed to each other through a discharge gap and are composed of a discharge electrode and a bus electrode for supplying power to the discharge electrode, and a front substrate so as to cover the display electrode At least 2 with respect to the discharge gap on the surface of each of the discharge cells on the discharge space side of the dielectric layer. One recess is formed, and the discharge electrode of the display electrode is formed to protrude vertically from the bus electrode toward the discharge gap so as to face the bottom surface of the recess via the discharge gap. Plasma display device.

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