This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for PLASMA DISPLAY PANEL earlier filed in the Korean Intellectual Property Office on 28 Oct. 2004 and there duly assigned Serial No. 10-2004-0086538.
1. Field of the Invention
The present invention relates to a novel design of a plasma display panel (PDP), and more particularly, to a PDP design that results in improved brightness and luminous efficiency while allowing for a reduced address discharge voltage.
2. Description of the Related Art
A PDP is a device that produces an image via an electric discharge. PDPs are becoming popular due to its predominant display performance, such as brightness and viewing angle. A principle of the PDP is that strong AC or DC voltage is applied to two electrodes to generate gas discharge that radiates ultraviolet rays, and radiation of the ultraviolet rays excites a phosphor layer within a discharge cell to produce visible rays.
PDPs are classified into DC-type and AC-type PDPs according to a discharging manner. The DC-type PDP has a structure in which all electrodes are exposed to a discharge space and electric charges are directly moved between corresponding electrodes. The AC-type PDP has a structure in which at least one electrode is enclosed by a dielectric layer and discharge is caused by wall charge, without direct movement of electric charges between the corresponding electrodes.
Also, the PDP can be classified into facing discharge-type and surface discharge-type PDPs according to an arrangement structure of the electrodes. The facing discharge-type PDP includes pairs of sustain electrodes each positioned on upper and lower substrates, where discharge is vertically generated between the substrates. The surface discharge-type PDP includes pairs of sustain electrodes positioned on the same substrate, where discharge is generated parallel to the substrate. In spite of increased luminous efficiency, the facing discharge-type PDP has a disadvantage in that a phosphor layer is easily deteriorated by plasma. Recently, the surface discharge-type PDP has come into wide use.
However, surface discharge AC PDPs have limited performance because of their design. For example, the shape of the discharge cells limits the amount of phosphor that can be deposited within, thus limiting the amount of visible light that can be generated. When ultraviolet radiation is produced in the discharge cell, it is not uniformly transmitted to the phosphor, thus limiting brightness and luminance efficiency. Also, the address and the sustain electrodes are separated by a large distance requiring a large voltage to be applied to these electrodes to achieve the requisite address discharge. What is therefore needed is a design for a PDP that overcomes these problems.
It is therefore an object of the present invention to provide an improved design for a PDP.
It is also an object of the present invention to provide a design for a PDP that allows for more phosphor to be deposited in the discharge cells.
It is further an object of the present invention to provide a design for a PDP that produces a efficient discharge that can be uniformly transferred to the phosphor.
It is still an object of the present invention to provide a PDP where the distance between the address electrodes and the sustain electrodes is small.
It is yet an object of the present invention to provide a design for a PDP that results in improved brightness and improved luminous efficiency.
These and other objects may be achieved by a PDP that includes a lower substrate and an upper substrate arranged opposite to each other and spaced apart by a distance, with a discharge space being located between the substrates, a plurality of partitions located between the lower substrate and the upper substrate that partitions the discharge space into a plurality of discharge cells, a plurality of address electrodes located on an upper surface of the lower substrate, a first dielectric layer located on the upper surface of the lower substrate and covering the address electrodes, a plurality of first sustain electrodes having a closed loop corresponding to each discharge cell, a plurality of second sustain electrodes having a closed loop corresponding to each discharge cell while corresponding to the first sustain electrodes, and a phosphor layer located on the upper surface of the first dielectric layer and on sidewalls of the partitions.
A second dielectric layer can be located on inner sides of the first sustain electrodes, and a protective film can be located on a surface of the second dielectric layer. A protrusion made of a dielectric substance can protrude from the upper surface of the first dielectric layer into each discharge cell, and the second sustain electrode can be located on an upper surface of each protrusion. The protrusion can have a closed-loop that corresponds to a closed loop of the second sustain electrode.
A phosphor layer can be located on inner and outer walls of the protrusion, and a phosphor layer can be located at a lower surface of the upper substrate. A third dielectric layer can be located on the upper surface of the protrusion to cover the second sustain electrode, and a protective film can be located on a surface of the third dielectric layer. The first sustain electrode can have a cylindrical shape. The second sustain electrode can have a plate shape with an aperture located at a center thereof. The address electrode can have a band shape or a plate shape with an aperture located at a center thereof.
According to another aspect of the present invention, there is provided a PDP that includes a lower substrate and an upper substrate arranged opposite to each other and spaced apart by a distance, with a discharge space being located between the substrates, a plurality of partitions located between the lower substrate and the upper substrate that partitions the discharge space into a plurality of discharge cells, a plurality of address electrodes located on an upper surface of the lower substrate, a first dielectric layer located on the upper surface of the lower substrate that covers the address electrodes, a plurality of first sustain electrodes having a shape of a closed loop corresponding to each discharge cell, a second dielectric layer located on the lower surface of the upper substrate and covering the first sustain electrodes, a plurality of second sustain electrodes having a closed loop, each closed loop corresponding to each discharge cell while corresponding to the first sustain electrodes, and a phosphor layer located on the upper surface of the first dielectric layer and on sidewalls of the partitions.
The first and second sustain electrodes can have a plate shape with an aperture located at a center thereof. The address electrode can have a band shape or a plate shape with an aperture located at a center thereof. A bus electrode can be made of a non-transparent metal and can be located at an outer periphery of the first sustain electrode. The first sustain electrode can be made of indium tin oxide (ITO).
A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein:
Turning now to the FIGURES,
A plurality of address electrodes 11 having a stripe shape are arranged on an upper surface of the lower substrate 10. A first dielectric layer 12 covers the address electrodes 11. A discharge space between the upper substrate 20 and the lower substrate 10 is partitioned into discharge cells 14 on an upper surface of the first dielectric layer 12. A plurality of partitions 13 are located on the first dielectric layer 12 at constant intervals, so as to prevent electrical and optical interference between the discharge cells 14. A phosphor layer 15 of red R, green G and blue B is coated on an inner surface of the discharge cells 14 to a desired thickness, and the discharge cells 14 are filled with a discharge gas.
The upper substrate 20 is a transparent substrate mainly made of glass through which visible rays can transmit through. The upper substrate 20 is coupled to the lower substrate 10 with the partitions 13 located on top of the upper substrate 20. Pairs of sustain electrodes 21a and 21b are located in the shape of stripe along a direction perpendicular to the address electrodes 11 and under the upper substrate 20. The sustain electrodes 21a and 21b are made of transparent conductive material, such as indium tin oxide (ITO) allowing for visible rays to pass through. In order to reduce a line resistance along the sustain electrodes 21a and 21b, bus electrodes 22a and 22b made of metal material are located under a lower surface of each sustain electrode 21a and 21b, and have a width narrower than that of the sustain electrodes 21a and 21b. The sustain electrodes 21a and 21b and the bus electrodes 22a and 22b are covered by a second dielectric layer 23. A protective layer 24 is formed over the second dielectric layer 23 and is generally made of MgO. Protective layer 24 serves to prevent the second dielectric layer 23 from being sputtered by plasma particles. Protective layer 24 also serves to lower a discharge voltage by emitting secondary electrons.
The PDP 30 configured as described is limited in the amount of phosphor material that can be deposited in the discharge cells. In addition, there is a problem in that since the ultraviolet rays produced in the discharge cell can not be uniformly transmitted to the phosphor layer, thus limiting brightness and luminous efficiency of the PDP 30. Also, there is another problem in that since the distance between the address electrode and the sustain electrode is relatively large, the voltage applied to the address electrode must be high to achieve an address discharge.
Turning now to
Referring to
A plurality of address electrodes 111 are located on an upper surface of the lower substrate 110. The address electrodes 111 can have the shape of a band (or stripe) as illustrated of
A plurality of partitions 113 are located on an upper surface of the first dielectric layer 112 and are formed to have a desired height to partition the discharge space between the lower substrate 110 and the upper substrate 120 into a plurality of discharge cells 114. The partitions 113 serve to prevent electrical and optical interference between neighboring discharge cells 114.
A plurality of first sustain electrodes 121 are sandwiched between the upper surfaces of the partitions 113 and the lower surface of the upper substrate 120. The first sustain electrodes 121 form closed loops above the upper surfaces of the partitions 113, each closed loop corresponding to a discharge cell 114. Dielectric substance is interposed between the first sustain electrodes 121. The first sustain electrode 121 can be have a rectangular case shape electrode, as illustrated of
A second dielectric layer 123 is located between the upper surface of the partitions 113 and the lower surface of the upper substrate 120. The second dielectric layer 123 also covers inner surfaces of the first dielectric electrodes 121. A protective film (not illustrated) covers the second dielectric layer 123 to prevent the second dielectric layer 123 from being exposed to and damaged by plasma particles. This protective film that covers second dielectric layer 123 also allows for application of a lower discharge voltage by emitting secondary electrons. Preferably, the protective film is made of MgO.
A protrusion 116 made of a dielectric material extends to a desired height from the upper surface of the first dielectric layer 112. The protrusion 116 can be have a closed loop shape, and a second sustain electrode 117 of a closed loop corresponding to the first sustain electrode 121 is located on an upper surface of the protrusion 116. Alternatively, the protrusion 116 can be omitted and the second sustain electrode 117 can be located directly on the upper surface of the first dielectric layer 112 and still be within the scope of the present invention.
The second sustain electrode 117 can have a rectangular plate shape with an aperture located at the center thereof, as illustrated of
A phosphor layer 115 is located on the upper surface of the first dielectric layer 112 and on sidewalls of partitions 113 used to form an inner wall of the discharge cells 114. The phosphor layer 115 can also be located on inner and outer walls of the protrusion 116. Further, phosphor layer 115 can be located at a lower surface of the upper substrate 120. As a result, there is much more surface area for phosphor material to be deposited on for each discharge cell 114 of PDP 100 than in the PDP 30 of
Turning now to
Although the variations of the first embodiment show the first sustain electrode as having either a rectangular case shape or a cylindrical shape, in no way is the present invention so limited to these designs. Likewise, the second sustain electrode can also have other various shapes of a plate with an aperture located at the center thereof, besides the rectangular plate shape electrode 117 or the disk shape electrode 117′. Similarly, the address electrode can also have other various shapes of a plate with an aperture located at the center thereof instead of the band shape electrode 111, the rectangular plate shape electrode 111′ and the disk shape electrode 111″.
With the PDP 100 configured as described above, a sustain discharge is generated between the first sustain electrode 121 or 121′ and the second sustain electrode 117 or 117′. With the designs of
Also, with the designs of
In the PDP 100 of
Comparing the PDP 100 of
Turning now to
Referring to
A plurality of first sustain electrodes 221 are located on a lower surface of the upper substrate 220. The first sustain electrodes 221 is formed to have the shape of a closed loop and are formed on top of an upper surface of the partitions 213, each closed loop corresponding to a different discharge cell 214. The first sustain electrodes 221 can have a rectangular plate shape with an aperture located at the center thereof, as illustrated of
A second dielectric layer 223 is formed on the lower surface of the upper substrate 220 and covers both the first sustain electrodes 221 and the bus electrodes 222. Preferably, the second dielectric layer 223 is made of transparent material to allow visible rays generated in the discharge cells to pass through and be viewed by a viewer on the outside. A protective film 224 can be formed over the second dielectric layer 223 to prevent the second dielectric layer 223 from being sputtered and thus damaged by plasma particles. Protective film 224 also serves to reduce a discharge voltage by emitting secondary electrons. Preferably, the protective film 224 is made of MgO.
A protrusion 216 made of dielectric material extends to a desired height in each discharge cell 214 from the upper surface of the first dielectric layer 212. The protrusion 216 can have the shape of a closed loop, and a second sustain electrode 217 can be formed on top of the protrusion and thus also have the shape of a closed loop that corresponds to the closed loops of the first sustain electrode 221. Alternatively, the second sustain electrode 217 can be formed directly on the first dielectric layer 212. In such a scenario, no protrusion 216 is formed on the first dielectric layer 212. This is to say, the second sustain electrodes are arranged between the upper substrate 220 and the lower substrate 210.
The second sustain electrode 217 can have the shape of a rectangular plate with an aperture located at the center thereof, as illustrated of
In the second embodiment of the present invention, a phosphor layer 215 can be located on the upper surface of the first dielectric layer 212 and on sidewalls of the partitions 213 that forms an inner walls of the discharge cells 214. The phosphor layer 215 can also be located on inner and outer walls of the protrusions 216, allowing for more surface area and thus more phosphor material to be deposited in each discharge cell 214 than in the PDP 30 of
Turning now to
Although the first sustain electrode is described as having either a rectangular plate shape or a disk shape, the present invention is in no way so limited, as the first sustain electrode can have other shapes and still be within the scope of the present invention. Likewise, although the present invention describes the second sustain electrode as having either a rectangular plate shape or a disk shape, the present invention is in no way so limited, as the first sustain electrode can have other shapes and still be within the scope of the present invention. Again likewise, although the present invention describes the address electrode as having either a band shape, a rectangular plate shape or a disk shape, the present invention is in no way so limited as the address electrode can have other shapes and still be within the scope of the present invention.
With the PDP 200 configured as described above, a sustain discharge is generated between the first sustain electrode 221 or 221′ and the second sustain electrode 217 or 217′. Because the sustain discharge is generated in a surface-type manner for this second embodiment, luminous efficiency is improved. With the PDP 200 as designed according to this second embodiment, the address discharge voltage can be lowered, and more phosphor material can be placed within each discharge cell 214.
In conclusion, the PDPs according to the present invention have the following beneficial effects. First, since a sustain discharge is generated between the first and second sustain electrodes in either a mixed facing and surface discharge manner or in just a surface-type discharge manner, the ultraviolet radiation generated by these discharges uniformly transmits to the phosphor layer located on the inner wall of the discharge cell, which leads to improved brightness and improved luminous efficiency. Second, since a distance between the address electrode and the second sustain electrode in the embodiments of the present invention is smaller than that of PDP 30 of
While the present invention has been particularly illustrated and described with reference to exemplary embodiments depicted in the drawings, it will be understood by those of ordinary skill in the art that various changes and modifications in form and details can be made therein without departing from the spirit and scope of the present invention.
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