Patent Grant
7696691
This application claims the benefit of Korean Patent Application No. 10-2005-0009724, filed on Feb. 2, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a plasma display panel that can reduce ineffective power consumption and improve heat dissipation.
2. Description of the Related Technology
Plasma display panel (PDP) apparatuses can provide large screens and certain advantages, such as a high-quality image display, a very thin and light design, and a wide-range viewing angle. PDPs have attracted considerable attention as the most promising next-generation flat display devices, because they can be manufactured in a simplified manner and can be easily manufactured in a large size compared with other flat display panels.
Such PDPs are classified into a direct current (DC) type, an alternating current (AC) type, and a hybrid type according to discharge voltages applied to discharge cells. PDPs may also be classified into a facing discharge type and a surface discharge type according to the type of a discharge structure. In recent years, AC type PDPs having a surface discharge type three-electrode structure are generally used.
Common electrodes 12 and scan electrodes 13 together define discharge gaps and are formed on a bottom surface of the upper substrate 11. The common electrodes 12 and the scan electrodes 13 are buried in an upper dielectric layer 14. A protective layer 15 is formed on the lower surface of the upper dielectric layer 14.
Address electrodes 22, intersecting the common electrodes 12 and the scan electrodes 13, are formed on the upper surface of the lower substrate 21. The address electrodes 22 are buried in a lower dielectric layer 23. Barrier ribs 24 are arranged at predetermined intervals on the upper surface of the lower dielectric layer 23, thereby partitioning discharge spaces 25. A phosphor layer 26 is formed in each of the discharge spaces 25. The discharge spaces 25 are filled with discharge gas.
In the PDP 10, ultraviolet radiation is produced from plasma generated due to discharge in the discharge spaces 25. The ultraviolet light excites the phosphor layers 26. The excited phosphor layers 26 emit visible light, and thus an image is displayed using the visible light.
However, about 40% of the visible light emitted by the phosphor layers 26 are absorbed by the electrodes 12 and 13, the upper dielectric layer 14, and the protective layer 15 sequentially formed on the lower surface of the upper substrate 11 because those elements (12-15) block the light transmitting path of the PDP 10. Thus, the conventional PDP 10 has reduced luminous efficiency. Furthermore, when an image is being displayed for a long period of time, charged particles of the discharge gas are ion sputtered to the phosphor layers 26 due to an electrical field, so that image sticking or permanent afterimage occurs. This leads to reduction of the lifespan of the PDP 10.
One aspect of the present invention provides a plasma display panel including: i) an upper substrate, ii) a lower substrate facing the upper substrate, iii) a barrier structure disposed between the upper substrate and the lower substrate and defining discharge cells, the barrier structure having cavities, iv) upper discharge electrodes arranged at intervals within the barrier structure and each surrounding at least parts of the discharge cells, v) lower discharge electrodes arranged at intervals within the barrier structure, located under the upper discharge electrode, and each surrounding at least parts of the discharge cells and vi) phosphor layers formed in the discharge cells.
In one embodiment, each of the discharge cells may have a closed structure.
In one embodiment, the upper discharge electrodes may include upper discharge portions (or body portions) each having a shape that surrounds at least a part of each discharge cell and upper connection portions connecting the upper discharge portions to each other. In one embodiment, the lower discharge electrodes may include lower discharge portions (or body portions) each having a shape that surrounds at least a part of each discharge cell and lower connection portions connecting the lower discharge portions to each other.
In one embodiment, the cavities within the barrier structure may be vertically formed between upper discharge portions and between lower discharge portions.
In another embodiment, the cavities within the barrier structure may be further horizontally formed between the upper discharge portions and the lower discharge portions.
In one embodiment, the cavities within the barrier structure may be vertically connected to or disconnected from each other.
In one embodiment, the cavities within the barrier structure may be horizontally formed between the upper discharge portions and the lower discharge portions.
In one embodiment, the cavities within the barrier structure may be each formed around the discharge cells to have a shape corresponding to the shape of the discharge cells.
In one embodiment, address electrodes spaced from each other and surrounding at least parts of the discharge cells may be further included in the barrier structure and each run in a direction orthogonal to the running direction of each of the upper and lower discharge electrodes.
In one embodiment, the address electrodes may include address discharge portions having ring shapes to surround the discharge cells and address connection portions connecting the address discharge portions to each other.
In one embodiment, the cavities within the barrier structure may be vertically formed and disposed between upper discharge portions, between lower discharge portions, and between address discharge portions.
In another embodiment, the cavities within the barrier structure may be further horizontally formed and disposed between the upper discharge portions and the lower discharge portions and between the lower discharge portions and the address discharge portions.
In one embodiment, the cavities within the barrier structure may be vertically connected to or disconnected from each other.
In one embodiment, the cavities within the barrier structure may be horizontally formed and disposed between the upper discharge portions and the lower discharge portions and between the lower discharge portions and the address discharge portions.
In one embodiment, the cavities within the barrier structure may be each formed around the discharge cells to have a shape corresponding to the shape of the discharge cells.
In one embodiment, the upper discharge electrodes, the lower discharge electrodes, and the address electrodes may each be formed of conductive metal.
In one embodiment, grooves may be formed on a surface of the upper substrate close to the barrier structure such as to face the discharge cells, and the grooves may be coated with phosphor layers.
In one embodiment, when an image is displayed on the upper substrate by visible light transmitted by the upper substrate, the phosphor layers formed on the grooves formed on the upper substrate may be formed of transmissive phosphor.
In one embodiment, when an image is displayed on the lower substrate by visible light transmitted by the lower substrate, the phosphor layers formed on the grooves formed on the upper substrate may be formed of reflective phosphor.
In one embodiment, the upper discharge electrodes may run in a direction orthogonal to the running direction of the lower discharge electrodes.
In one embodiment, the barrier structure may be a dielectric.
In one embodiment, sidewalls of the barrier structure may be coated with MgO films.
According to one embodiment of the present invention, a barrier structure formed of a dielectric has cavities, so that permittivity is reduced. This reduces capacitance, and thus ineffective power consumption can be reduced. In addition, since discharge occurs in the entire space of each discharge cell, the size of an area where discharge occurs greatly increases. Thus, low-voltage driving is possible, and luminance and light emission efficiency can improve.
Furthermore, heat dissipation can be greatly improved due to a convective operation through the air existing within the cavities.
Embodiments of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.
Embodiments of the present invention will now be described more fully with reference to the accompanying drawings.
Referring to
A barrier structure 131 is disposed between the upper and lower substrates 111 and 121. The barrier structure 131 partitions a plurality of discharge cells 132 corresponding to sub-pixels and prevents occurrence of undesired discharge due to cross talk or the like between discharge cells 132. In one embodiment, the barrier structure 131 may be designed so that the discharge cells 132 have closed structures. In one embodiment, as shown in
In one embodiment, the barrier structure 131 is formed of a dielectric. In this case, an electric current can be prevented from flowing directly among upper discharge electrodes 141, lower discharge electrodes 142, and address electrodes 143, which are disposed within the barrier structure 131. In addition, the three electrodes 141-143 are prevented from being damaged due to a collision with charged particles generated during discharge. Furthermore, accumulating wall charges becomes easy due to induction of the charged particles. In one embodiment, the barrier structure 131 may be formed of PbO, B2O3, or SiO2.
In one embodiment, an MgO film 133 having a predetermined thickness may be further formed as a protective film on inner sidewalls of the barrier structure 131. In this embodiment, direct collision of the charged particles with the barrier structure 131 can be prevented by the MgO film 133. Consequently, damage to the barrier structure 131 due to ion sputtering of the charged particles can be prevented. In addition, since the charged particles directly collide the MgO film 133, secondary electrons that contribute to discharge are emitted from the MgO film 133. Thus, low-voltage driving is realized, and luminous efficiency increases.
Phosphor layers 113, which are excited by ultraviolet radiation generated during discharge and emit visible light, are arranged in the discharge cells 132. In one embodiment, as shown in
In one embodiment, in cases where the phosphor layers 113 are disposed on the upper substrate 111, the phosphor layers 113 may be formed of transmissive phosphor so that the visible light passes through the upper substrate 111 to display an image. In another embodiment, in order for the visible light to be transmitted by the lower substrate 121 to display an image, the phosphor layers 113 are preferably formed of reflective phosphor. In another embodiment, the grooves 112 may be formed on the top surface of the lower substrate 121 to face the discharge cells 132 in a one-to-one correspondence, and the inner surfaces of the grooves 112 may be coated with the phosphor layers 113.
As the phosphor layers 113 are accommodated within the grooves 112 formed in the upper substrate 111, the phosphor layers 113 can be sufficiently spaced from main areas where discharge occurs. Accordingly, the phosphor layers 113 can be prevented from being ion-sputtered by the charged particles, resulting in an increase in the lifespan of the PDP 100. In addition, although an image is displayed for a long period of time, the frequency of occurrence of image sticking or permanent image can be remarkably reduced.
Each of the phosphor layers 113 is generally formed of one of red, green, and blue phosphors that emit red, green, and blue visible light, respectively, to accomplish color display. Consequently, the phosphor layers 113 include red, green, and blue phosphor layers. Sub pixels are divided into red sub-pixels, green sub-pixels, and blue sub-pixels according to which of the red, green, and blue phosphor layers is disposed over a discharge cells. The red, green, and blue sub-pixels are included in a unit pixel, and thus a single unit pixel displays various colors depending on a combination of the three colors.
The discharge cells 132 covered with the phosphor layers 113 are filled with discharge gas. In one embodiment, the discharge gas may be a mixture of gas that generates ultraviolet light, such as, Xe, and gas that serves as a buffer, such as, Ne.
Upper discharge electrodes 141 and lower discharge electrodes 142 extend in the same direction and parallel to each other within the barrier structure 131 that partitions the discharge cells 132. In one embodiment, the discharge electrodes 141 and 142 are disposed one over another to surround the discharge cells 132 together. The upper discharge electrodes 141 are closer to the upper substrate 111 than the lower discharge electrodes 142.
One of the discharge electrodes 141 and 142 serves as common electrodes, and the other serves as scan electrodes. In one embodiment, in cases where address electrodes 143 are located under the lower discharge electrodes 142 as shown in
The upper discharge electrodes 141 are spaced from one another at predetermined intervals and each extend in one direction. In one embodiment, the upper discharge electrodes 141 may be designed so as to fully surround the discharge cells 132, which are arranged in the extending direction of the upper discharge electrodes 141. In one embodiment, each of the upper discharge electrodes 141 may have an array of body portions 141a, each having a ring shape to surround each of the discharge cells 132, and an array of upper connection portions 141b that connect the body portions 141a to each other. In one embodiment, the body portions 141a have shapes corresponding to the shapes of the discharge cells 132 such that each of the body portions 141a is spaced from its corresponding discharge cell 132 by a constant distance.
The lower discharge electrodes 142 extend in the same direction as the extending direction of the upper discharge electrodes 141 and are spaced from each other at predetermined intervals. In one embodiment, like the upper discharge electrodes 141, the lower discharge electrodes 142 may be designed so as to fully surround the discharge cells 132, which are arranged in the extending direction of the lower discharge electrodes 142. In one embodiment, each of the lower discharge electrodes 142 may have an array of body portions 142a, each having a ring shape to surround each of the discharge cells 132, and an array of lower connection portions 142b that connect the body portions 142a to each other. Each of the upper and lower discharge electrodes may have various other shapes and is not limited to the ring shape.
The address electrodes 143 within the barrier structure 131 produce address discharge together with scan electrodes (i.e., either the upper discharge electrodes 141 or the lower discharge electrodes 142) so that a discharge cell 132 is selected. To achieve this, the address electrodes 143 are spaced from each other and each extend in a direction perpendicular to the extending direction of the upper and lower discharge electrodes 141 and 142. In one embodiment, as illustrated in
In one embodiment, in contrast to
In one embodiment, the body portions 141a of the upper discharge electrodes 141, the body portions 142a of the lower discharge electrodes 142, and the address discharge portions 143a are shaped to surround the discharge cells 132 as shown in
In one embodiment, cavities 131a as illustrated in
Furthermore, the cavities 131a rapidly emit a great amount of heat generated in the discharge cells 132 during gas discharge to the outside due to a convective action through the air existing in the cavities 131a.
In another embodiment, the cavities 131a may be disposed between body portions 142a and between address discharge portions 143a. In another embodiment, as illustrated in
The sustain discharge occurs near inner sidewalls of the barrier structure 131 that defines the discharge cells 132 and spreads to the centers of the discharge cells 132. Hence, the area where discharge occurs increases compared to the conventional art, and the area where sustain discharge occurs increases, so that spatial charges not used in the conventional art contribute to light emission. Accordingly, the amount of plasma produced during discharge can increase, so that low-voltage driving is possible. Due to the sustain discharge caused by such a mechanism, ultraviolet light is emitted from discharge gas and excites the phosphor layers 113 formed in the discharge cells 132 to emit visible light.
In another embodiment, as illustrated in
In another embodiment, as illustrated in
In another embodiment, as illustrated in
The remaining elements are the same as those of the
Referring to
A barrier structure 531 which partitions discharge cells 532 and in which cavities 531a are formed is disposed between the upper substrate 511 and the lower substrates 521.
Upper discharge electrodes 541, lower discharge electrodes 542, and address electrodes 543 are disposed within the barrier structure 531. Inner sidewalls of the barrier structure 531 may be coated with MgO films 533 with a predetermined thickness to serve as protective layers.
In one embodiment, the upper discharge electrodes 541 include body portions 541a and upper connection portions 541b.
In one embodiment, the lower discharge electrodes 542 include body portions 542a and lower connection portions 542b.
The PDP 500 of
In one embodiment, the first barrier ribs 531b surround the discharge cells 532 and each has a shape of a tube whose cross-section is a circular ring. In one embodiment, the second barrier ribs 531c are in the shape of islands. In this embodiment, the volume of the cavities 531a increases compared with that of the PDP 100 to further reduce permittivity between body portions 541a, between body portions 542a, and between address discharge portions 543a than the PDP 100. Accordingly, the capacitance decreases, resulting in a further reduction of ineffective power consumption than the PDP 100.
In addition, when the PDP 500 operates, a large amount of heat generated in the discharge cells 532 can be rapidly discharged to the outside due to a convective operation through the air existing within the cavities 531a.
Since the other components and operations thereof in the PDP 500 are almost the same as those in the PDP 100, a detailed description thereof will be omitted.
Referring to
A barrier structure 631 which partitions discharge cells 632 and in which cavities 631a are formed is disposed between the upper and lower substrates 611 and 621.
Upper discharge electrodes 641, lower discharge electrodes 642, and address electrodes 643 are disposed within the barrier structure 631. Inner sidewalls of the barrier structure 631 may be coated with MgO films 633 with a predetermined thickness to serve as protective layers.
In one embodiment, the upper discharge electrodes 641 include body portions 641a and upper connection portions 641b.
In one embodiment, the lower discharge electrodes 642 include body portions 642a and lower connection portions 642b.
The PDP 600 is different from the PDP 100 in that the cavities 631a vertically extend across the barrier structure 631, namely, from one end of the barrier structure 631 to the other end thereof, instead of extending by a part of the barrier structure 631, so as to surround the discharge cells 632 and are connected to one another. In one embodiment, the barrier structure 631 includes the cavities 631a and barrier ribs 631b. The barrier ribs 631b surround the discharge cells 632 and each have a shape of a tube whose cross-section is a circular ring. However, the prevent invention is not limited to the circular-ring cross-section. That is, the cross-section of each of the barrier ribs 631b may be any ring as long as it can surround each of the discharge cells 632, for example, a rectangular ring, a polygonal ring, or an oval ring.
In
In contrast with the barrier structure 531, the barrier structure 631 does not include island-type barrier ribs like the second barrier ribs 531c. Hence, the volume of the cavities 631a is larger than that of the cavities 531a.
In this embodiment, the size of the cavities 631a drastically increases compared with those of the PDPs 100 and 500 to further reduce permittivity between body portions 641a, between body portions 642a, and between address discharge portions 643a than the PDPs 100 and 500. Accordingly, the capacitance decreases, resulting in a further reduction of ineffective power consumption than the PDPs 100 and 500.
In addition, when the PDP 600 operates, a large amount of heat generated in the discharge cells 632 can be rapidly discharged to the outside due to a convective operation through the air existing within the cavities 631a.
Since the other components and operations thereof in the PDP 600 are almost the same as those in the PDP 100, a detailed description thereof will be omitted.
As described above, PDPs according to embodiments of the present invention can reduce ineffective power consumption and greatly improve heat discharge.
While the above description has pointed out novel features of the invention as applied to various embodiments, the skilled person will understand that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made without departing from the scope of the invention. Therefore, the scope of the invention is defined by the appended claims rather than by the foregoing description. All variations coming within the meaning and range of equivalency of the claims are embraced within their scope.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2005-0009724 | Feb 2005 | KR | national |
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| 20060170352 | Jung et al. | Aug 2006 | A1 |
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| Number | Date | Country | |
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| 20060170353 A1 | Aug 2006 | US |
