Patent Application
20080042571
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.
As shown in
The sustain electrode pair 11 and 12 includes transparent electrodes 11a and 12a and bus electrodes 11b and 12b that are generally made of indium-tin-oxide (ITO). The bus electrodes 11b and 12b can be made of a metal such as silver (Ag) and chrome (Cr) or can be made with a stacked structure of chrome/copper/chrome (Cr/Cu/Cr) or chrome/aluminum/chrome (Cr/Al/Cr). The bus electrodes 11b and 12b are formed on the transparent electrodes 11a and 12a to reduce voltage drop due to the transparent electrodes 11a and 12a having high resistance.
Meanwhile, according to an embodiment of the present invention, the sustain electrode pair 11 and 12 can be composed of a stacked structure of the transparent electrodes 11a 12a and the bus electrodes 11b and 12b or only the bus electrodes 11b and 12b without the transparent electrodes 11a and 12a. Because the latter structure does not use the transparent electrodes 11a and 12a, there is an advantage in that a cost of manufacturing a panel can be decreased. The bus electrodes 11b and 12b used in the structure can be made of various materials such as a photosensitive material in addition to the above-described materials.
A black matrix (BM) 15, which performs a light shielding function of reducing reflection by absorbing external light that is generated from the outside of the upper substrate 10 and a function of improving purity and contrast of the upper substrate 10 may be arranged between the transparent electrodes 11a and 12a and the bus electrodes 11b and 12b of the scan electrode 11 and the sustain electrode 12.
The black matrix 15 according to an embodiment of the present invention is formed in the upper substrate 10 and includes a first black matrix 15 that is formed in a position that is overlapped with a barrier rib 21 and second black matrixes 11c and 12c that are formed between the transparent electrodes 11a and 12a and the bus electrodes 11b and 12b. Here, the first black matrix and the second black matrixes 11c and 12c that are also referred to as a black layer or a black electrode layer may be physically connected to each other when they are formed at the same time in a forming process or may be not physically connected to each other when they are not formed at the same time.
In addition, when they are physically connected to each other, the first black matrix 15 and the second black matrixes 11c and 12c are made of the same material, but when they are physically separated from each other, they may be made of other materials.
It is also possible for bus electrodes 11b and 12b and the barrier rib 21 to perform a light shielding function of reducing reflection by absorbing external light generated from the outside and a function of improving contrast such as the black matrixes, as the bus electrodes 11b and 12b and the barrier rib 21 are dark colored. Otherwise, it is also possible to perform a function of the black matrix by making the overlapped portion viewed from the front looks like black color, as a specific element, for example a dielectric layer 13, formed in the upper substrate 10, and a specific element, for example the barrier rib 21, formed in the lower substrate 20 are complementarily colored.
An upper dielectric layer 13 and a protective film 14 are stacked in the upper substrate 10 in which the scan electrode 11 and the sustain electrode 12 are formed in parallel. Charged particles, which are generated by a discharge are accumulated in the upper dielectric layer 13 and perform a function of protecting the sustain electrode pair 11 and 12. The protective film 14 protects the upper dielectric layer 13 from sputtering of charged particles that are generated at a gas discharge and enhances emission efficiency of a secondary electron.
In addition, the address electrode 22 is formed in an intersecting direction of the scan electrode 11 and the sustain electrode 12. Furthermore, a lower dielectric layer 24 and a barrier rib 21 are formed on the lower substrate 20 in which the address electrode 22 is formed.
In addition, a phosphor layer 23 is formed on the surface of the lower dielectric layer 24 and the barrier rib 21. In the barrier rib 21, a vertical barrier rib 21a and a horizontal barrier rib 21b are formed in a closed manner and the barrier rib 21 physically divides a discharge cell and prevents ultraviolet rays and visible light that are generated by a discharge from leaking to adjacent discharge cells.
Referring to
In case that the distance between the filter 100 and the PDP is 10 μm to 30 μm, it is possible to effectively shield light incident upon the PDP and to effectively emit light generated from the PDP to the outside. Also, the distance between the filter 100 and the PDP may be 30 μm to 120 μm in order to protect the PDP from the exterior pressure, and an adhesion layer, which absorbs impact, may be formed between the filter 100 and the PDP.
In an embodiment of the present invention, various shapes of barrier rib 21 structure as well as the barrier rib 21 structure shown in
In the differential type barrier rib structure, it is more preferable that a height of the horizontal barrier rib 21b is higher than that of the vertical barrier rib 21a and in the channel type barrier rib structure or the hollow type barrier rib structure, it is preferable that a channel or a hollow is formed in the horizontal barrier rib 21b.
Meanwhile, in an embodiment of the present invention, it is described as each of R, G, and B discharge cells is arranged on the same line, but they may be arranged in other shapes. For example, delta type of arrangement in which the R, G, and B discharge cells are arranged in a triangle shape may be also used. Furthermore, the discharge cell may have various polygonal shapes such as a quadrilateral shape, a pentagonal shape, and a hexagonal shape.
Furthermore, the phosphor layer 23 emits light by ultraviolet rays that are generated at a gas discharge and generates any one visible light among red color R, green color G, or blue color B light. Here, inert mixed gas such as He+Xe, Ne+Xe, and He+Ne+Xe for performing a discharge is injected into a discharge space that is provided between the upper/lower substrates 10, 20 and the barrier rib 21.
The base unit 200 is preferably formed of a transparent plastic material, for example a UV-hardened resin-based material, so that light can smoothly transmit therethrough. Alternately, it is possible to use a hard glass material to protect the front of the PDP.
Referring to
According to
In general, an external light source is mostly located over the PDP, and thus external light is diagonally incident on the PDP from the top side and is absorbed in the pattern units 210.
The pattern units 210 may include a light-absorbing particle, and the light-absorbing particle may be a resin particle colored by a specific color. In order to maximize the light absorbing effect, the light-absorbing particle is preferably colored by a black color.
In order to maximize the absorption of external light and to facilitate the manufacture of the light-absorbing particle and the insertion into the pattern units 210, the size of the light-absorbing particle may be 1 μm or more. Also, in case that the size of the light-absorbing particle is 1 μm or more, the pattern units 210 may include the light-absorbing particle 10% weight or more in order to absorb external light more effectively. That is, the light-absorbing particle 10% weight or more of the total weight of the pattern units 210 may be included in the pattern units 210.
According to
As described in the above, external light which reduces the bright room contrast of the PDP is highly likely to be above the PDP. Referring to
Also, light (illustrated as a solid line) that is emitted from the PDP 310 for displaying is totally reflected from the slanted surface of the pattern units 305 to the outside, i.e., toward the viewer.
As described above, external light (illustrated as a dotted line) is refracted into and absorbed by the pattern units 305 and light (illustrated as a solid line) emitted from the PDP 310 is totally reflected by the pattern units 305 because the angle between the external light and the slanted surface of the pattern units 305 is greater than the angle between the light emitted from the PDP 310 and the slanted surface of the pattern units 305, as illustrated in
Therefore, the external light shielding sheet according to the present invention enhances the bright room contrast of the display image by absorbing the external light to prevent the external light from being reflected toward the viewer and by increasing the reflection of light emitted from the PDP 310.
In order to maximize the absorption of external light and the total reflection of light emitted from the PDP 310 in consideration of the angle of external light incident upon the PDP 310, the refractive index of the pattern units 305 is preferably 0.3-1 times higher than the refractive index of the base unit 300. In order to maximize the total reflection of light emitted from the PDP 310 in consideration of the vertical viewing angle of the PDP, the refractive index of the pattern units 305 is preferably 0.3-0.8 times higher than the refractive index of the base unit 300.
As shown in
Therefore, the ghost phenomenon may be reduced when the top of the pattern units 325 is arranged at the viewer side and the refractive index of the pattern units 325 is higher than the refractive index of the base unit 320. The difference between the refractive index of the pattern units 325 and the refractive index of the base unit 320 is preferably 0.05 and more in order to prevent the ghost phenomenon by sufficiently absorbing light emitted from the PDP that is diagonally incident upon the pattern units 325.
When the refractive index of the pattern units 325 is higher than the refractive index of the base unit 320, light transmittance ratio of the external light shielding sheet and bright room contrast may be reduced. Therefore, the difference between the refractive index of the pattern units 325 and the refractive index of the base unit 320 is preferably 0.05 in order to prevent the ghost phenomenon and in order not to considerably reduce light transmittance ratio of the external light shielding sheet. Also, the refractive index of the pattern units 325 is preferably 1.0-1.3 times greater than the refractive index of the base unit 320 to maintain the bright room contrast as well as to prevent the ghost phenomenon.
As shown in
The distance d between the PDP 350 and the external light shielding sheet is preferably 1.5 to 3.5 mm in order to prevent the ghost phenomenon as light from the PDP is reflected from the slanted surface of the pattern units 345 and is collected around light from the PDP which passes through the base unit 340.
In addition, the external light absorbing effect can be enhanced, since the refractive index of the pattern units 365 is higher than the refractive index of the base unit 360.
Referring to
The height h of the pattern units 410 is set to 80 μm to 170 μm, and thus, it is possible to make a gradient of the slanted surface capable of effectively absorbing external light and reflecting light emitted from the PDP. Also, it is also possible to prevent the pattern units 410 from being short-circuited.
In order to achieve a sufficient opening ratio to display images with optimum luminance through discharge of light emitted from the PDP toward the user side and to provide an optimum gradient of the slanted surface of the pattern units 410 for enhancing the external light shielding efficiency and the reflection efficiency, the distance D1 between a pair of adjacent pattern units may be set to 40 μm to 90 μm, and the distance D2 between tops of the pair of adjacent pattern units may be set to 90 μm to 130 μm.
Due to the above-described reasons, an optimum opening ratio for displaying images can be obtained when the distance D1 is 1.1 to 5 times greater than the bottom width P1 of the pattern units 410. Also, in order to obtain an optimum opening ratio and to optimize the external light shielding efficiency and the reflection efficiency, the distance D1 between bottoms of the pair of adjacent pattern units 410 may be set to be 1.5 to 3.5 greater than the bottom width of the pattern units 410.
When the height h is 0.89 to 4.25 times greater than the distance D1 between the pair of adjacent pattern units, external light diagonally incident upon the external light shielding sheet from above can be prevented from being incident upon the PDP. Also, in order to prevent the pattern units 410 from being short-circuited and to optimize the reflection of light emitted from the PDP, the height h of the pattern units 410 may be set to be 1.5 to 3 times greater than the distance D1 between the pair of adjacent pattern units.
In addition, when the distance D2 between tops of a pair of adjacent pattern units is 1 to 3.25 times greater than the distance D1 between bottoms of a pair of adjacent pattern units, a sufficient opening ratio for displaying images with optimum luminance can be obtained. Also, in order to maximize the total reflection of light emitted from the PDP by the slanted surface of the pattern units 410, the distance D2 between tops of the pair of adjacent pattern units may be set to be 1.2 to 2.5 times greater than the distance D1 between bottoms of the pair of adjacent pattern units.
Although a structure of the external light shielding sheet according to the present invention is explained with the case where the top of the pattern units 410 are arranged at a viewer side, however, it is also applicable to the case when the bottom of the pattern units 410 is arranged at the viewer side.
The moire phenomenon may be generated, as a black matrix, a black layer, a bus electrode and a barrier rib formed in the display panel and a plurality of pattern units 410 that are formed in the external light shielding sheet are overlapped. The moire phenomenon is a pattern of low frequency caused by the interference between periodic images, for example there is a pattern in the shape of wave when mosquito nets are stacked.
In the shape of the front surface of the external light shielding sheet according to the moire phenomenon, the moire phenomenon which is generated as a black matrix, a black layer, a bus electrode and a barrier rib formed in the PDP are overlapped with a plurality of pattern units 410, can be reduced by diagonally forming the plurality of pattern units 410.
For reducing the moire phenomenon, the slanted angle of the plurality of pattern units 410 is preferably 0.5 to 20 degrees. That is, the moire phenomenon may be reduced when the pattern units 410 of the external light shielding sheet are diagonally formed with a black matrix, a black layer, a bus electrode and a barrier rib formed in the PDP at an angle of 0.5 to 20 degrees. Also, in consideration that an external light source is mostly located over the head of a viewer, an appropriate opening ratio is obtained as well as the moire phenomenon is prevented when the slanted angle is 0.5 to 5 degrees, and thus, it is possible to enhance the reflection efficiency of light emitted from the PDP and to effectively shield external light.
Referring to
Referring to
As illustrated in
Referring to
A cross sectional shape of at least one of the pattern unit's edge portions 720, 730, 740, for example, a top edge 720 is pointed at the end.
In order to prevent the pattern units 710 from being detached from the base unit 700 when laminating the external light shielding sheet according to the present invention to the film or the glass and to prevent the pattern units 710 from being detached from the base unit 700 due to impact caused by heat or pressure, a radius of curvature of the edge portions 720, 730, 740 of the pattern units 710 is preferably 10 μm to 3 mm.
Referring to
Referring to
Referring to
Also, the pattern units 810 may absorb external light incident upon the PDP at various incident angles by forming the top edge of the pattern units 810 as a curved profile.
In order to prevent the pattern units 810 from being detached from the base unit 800 because of laminating or impact caused by heat or pressure as well as to effectively absorb external light, a radius of curvature r1, r2, r3 of the edge portions, in particular a radius of curvature r1, r2, r3 of the top edge portion is preferably 100 μm to 800 μm.
Referring to
For the external light shielding sheet as illustrated in
Referring to
Referring to
As shown in
That is, the pattern units 1010 having a concave bottom 1015 may be formed by forming the pattern units 1010 in which the height of the center area is lower than the height of the outer most contour.
The pattern units 1010 may be formed by filling light-absorbing materials into grooves formed in the base unit 1000, wherein some of the grooves formed in the base unit 1000 may be filled by the light-absorbing materials and the rest of the grooves may be left as an occupied space. Therefore, the bottom 1015 of the pattern units 1010 may be a concave shape in which the center area is depressed into the inside.
As shown in
Referring to
Referring to
As described in Table 1, the sharpness of the display images may be enhanced by reducing the bleeding phenomenon of the display images, when a depth a of the depressed groove formed in the bottom of the pattern units 1210 is 1.5 μm to 7.0 μm.
Also, the depth a formed in the bottom of the pattern units 1210 is preferably 2 μm to 5 μm in consideration of the protection of the pattern units 1210 from the exterior pressure, and the manufacturing facilitation of the pattern units 1210.
As described in the above with reference to
Meanwhile, it is possible to form a gradient of the slanted surface capable of optimizing the absorption of external light and the reflection of light emitted from the PDP, when a height c of the pattern units 1210 is 80 μm to 170 μm, and thus, the height c of the pattern units 1210 is preferably set to be 16 to 85 times greater than the depth a of the groove formed on the bottom of the pattern units 1210 between the pair of adjacent pattern units.
Also, the thickness b of the external light shielding sheet is preferably set to be 20 to 90 times greater than the depth a of the groove formed in the bottom of the pattern units 1210, because it is possible to obtain the appropriate transmittance of light emitted from the PDP, the absorption and the shielding as well as the durability of the external light shielding sheet when the thickness b of the external light shielding sheet is 100 μm to 180 μm.
Referring to
Referring to
When the height h provided in the external light shielding sheet is 80 μm to 170 μm, the manufacture of the external light shielding sheet can be facilitated, the appropriate opening ratio of the external light shielding sheet can be obtained, and the function of shielding external light and the function of reflecting light emitted from the PDP can be maximized.
The height h of the pattern units can be varied according to the thickness T of the external light shielding sheet. In general, external light that considerably affects the bright room contrast of the PDP is highly likely to be incident upon the PDP from the above. Therefore, in order to effectively shield external light with an angle θwithin a predetermined range, the height h of the pattern units is preferably within a predetermined percentage of the thickness T of the external light shielding sheet.
As the height h of the pattern units increases, the thickness of the base unit, which is top region of the pattern units, decreases, and thus, dielectric breakdown may occur. On the other hand, as the height h of the pattern units decreases, more external light is likely to be incident upon the PDP at various angles within a predetermined range, and thus the external light shielding sheet may not properly shield the external light.
Table 2 presents experimental results about the dielectric breakdown and the external light shielding effect of the external light shielding sheet according to the thickness T of the external light shielding sheet and the height h of the pattern units.
Referring to Table 2, when the thickness T of the external light shielding sheet is 120 μm or more, and the height h of the pattern units 115 μm or more, the pattern units are highly likely to dielectric breakdown, thereby increasing defect rates of the product. When the height h of the pattern units 115 μm or less, the pattern units are less likely to dielectric breakdown, thereby reducing defect rates of the external light shielding sheet. However, when the height h of the pattern units is 85 μm or less, the shielding efficiency of external light may be reduced, and when the height h of the pattern units is 60 μm or less, external light is likely to be directly incident upon the PDP. Therefore, when the height h of the pattern units is 90 μm to 110 μm, the shielding efficiency of the external light shielding sheet may be increased as well as the defect rates of the external light shielding sheet may be decreased.
In addition, when the thickness T of the external light shielding sheet is 1.01 to 2.25 times greater than the height h of the pattern units, it is possible to prevent the top portion of the pattern units from dielectrically breaking down and to prevent external light from being incident upon the PDP. Also, in order to prevent dielectric breakdown and infiltration of external light into the PDP, to increase the reflection of light emitted from the PDP, and to secure optimum viewing angles, the thickness T the external light shielding sheet may be 1.01 to 1.5 times greater than the height h of the pattern units.
Table 3 presents experimental results about the occurrence of the moire phenomenon and the external light shielding effect of the external light shielding sheet according to different pattern unit bottom width P1-to-bus electrode width ratios, when the width of the bus electrode is 70 μm.
Referring to Table 3, when the bottom width of the pattern units is 0.2 to 0.5 times greater than the bus electrode width, the moire phenomenon can be reduced as well as external light incident upon the PDP can be reduced. Also, in order to prevent the moire phenomenon, to effectively shield external light, and to secure a sufficient opening ratio for discharging light emitted from the PDP, the bottom width of the pattern units is preferably 0.25 to 0.4 times greater than the bus electrode width.
Table 4 presents experimental results about the occurrence of the moire phenomenon and the external light shielding effect according to different pattern unit bottom width of the external light shielding sheet-to-vertical barrier rib width ratios, when the width of the vertical barrier rib is 50 μm.
Referring to Table 4, when the bottom width of the pattern units is 0.3 to 0.8 times greater than the top width of the vertical barrier rib, the moire phenomenon can be reduced as well as external light incident upon the PDP can be reduced. Also, in order to prevent the moire phenomenon, to effectively shield external light, and to secure a sufficient opening ratio for discharging light emitted from the PDP, the bottom width of the pattern units is preferably 0.4 to 0.65 times greater than the top width of the vertical barrier rib.
Referring to
The electromagnetic interference (EMI) sheet 1320 includes an electromagnetic interference (EMI) layer 1321 which is attached onto a front surface of the base sheet 1322 which is formed of a transparent plastic material and shields EMI emitted from the PDP so that the EMI can be prevented from being released to the outside. Here, the electromagnetic interference (EMI) layer 1321 is generally formed of a conductive material in a mesh form. An invalid display area of the electromagnetic interference (EMI) sheet 1320 where no image is displayed is covered with a conductive material in order to properly ground the electromagnetic interference (EMI) layer.
In general, an external light source is mostly located over the head of a viewer regardless of an indoor or outdoor environment. The external light shielding sheet 1330 is attached thereto so that external light is effectively shielded and thus black images of the PDP can be rendered even blacker.
An adhesive layer 1340 is interposed between the AR/NIR sheet 1310, the electromagnetic interference (EMI) sheet 1320 and the external light shielding sheet 1330, so that the sheets 1310, 1320, 1330 and the filter 1300 can be firmly attached onto the front surface of the PDP. Also, the base sheets interposed between the sheets 1310, 1320, 1330 are preferably made of the same material in order to facilitate the manufacture of the filter 1300.
Meanwhile, according to
Referring to
At least one of the base sheets illustrated in
In addition, the filter according to the present invention may further include a diffusion sheet. The diffusion sheet serves to diffuse light incident upon the PDP to maintain the uniform brightness. Therefore, the diffusion sheet may widen the vertical viewing angle and conceal the patterns formed on the external light shielding sheet by uniformly diffusing light emitted from the PDP. Also, the diffusion sheet may enhance the front luminance as well as antistatic property by concentrating light in the direction corresponding to the vertical viewing angle.
As a diffusion sheet, a transmissive diffusion film or a reflective diffusion film can be used. The diffusion sheet may have the mixed form that small glass particles are mixed in the base sheet of polymer material. Also, PMMA may be used as a base sheet of the diffusion film. When PMMA is used as a base sheet of the diffusion film, it can be used in large display devices because thermal resistance of the base sheet is good enough despite of it's thick thickness.
According to the present invention, it is possible to effectively realize black images and enhance bright room contrast by arranging the external light shielding sheet, which absorbs and shields external light from the outside, at the front of the display panel. Also, it is possible to prevent the pattern units from being detached from the base unit due to external impact and to effectively shield external light incident upon the PDP from various directions by forming the edge portions or the bottom of the pattern units as a curve having a predetermined curvature.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. It is, therefore, intended that such changes and modifications be covered by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2006-0078264 | Aug 2006 | KR | national |
| 10-2006-0108664 | Nov 2006 | KR | national |
