BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a conventional color plasma display structure according to the prior art.
FIG. 2 is a side view of a sub-pixel of the color plasma display panel of FIG. 1, taken along a plane perpendicular to a long dimension of an address electrode.
FIG. 3 is another side view of a sub-pixel of the color plasma display panel of FIG. 1, taken along a plane parallel to the long dimension of the address electrode, and showing the sub-pixel in a plane perpendicular to the plane of FIG. 2.
FIG. 4 is a diagram of a driving scheme of an address display separation (ADS) gray scale technique, showing a frame time divided into sub-fields.
FIG. 5 is a diagram of a PDP pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 6 is a diagram of another embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 7 is a diagram of a second embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 8 is a diagram of a third embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 9 is a diagram of a fourth embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 10 is a diagram of a fifth embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 11 is a diagram of a sixth embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 12 is a diagram of a seventh embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 13 is a diagram of an eighth embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 14 is a diagram of a ninth embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 15 is a diagram of a tenth embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 16 is a diagram of an eleventh embodiment of a pixel structure with a transparent dielectric stand of the present disclosure.
FIG. 17 is a diagram of a twelfth embodiment of a pixel structure with a dielectric stand of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
A long discharge path within a sub-pixel of a PDP is believed to improve the discharge efficiency of that sub-pixel because a positive column is involved in the discharge. A high-resolution PDP limits the size of each sub-pixel, so that the only way to increase the discharge path is in the dimension perpendicular to the flat plane of the front plate of the panel. The present disclosure thus describes a structure comprising a dielectric step or stand between two electrodes, across the sustain gap, and on top of the dielectric layer on the front plate in each sub-pixel of a PDP. The particular structure can lengthen the discharge path in the dimension that is perpendicular to the front plate. As a result, there is a significant improvement in luminescence efficiency over currently available models, even in HD resolution PDPs. The structure can also reduce the discharge voltage needed for each sub-pixel because of field enhancement near the bottom edge of the step.
In the first embodiment shown in FIG. 5, a transparent dielectric stand 519 is placed on top of dielectric layer 513 and in between scan electrode 511 and sustain electrode 512 on the front plate 510. The protective layer 514 is coated on top of dielectric layer 513 and dielectric stand 519. In the shown embodiment, the protective coating is made of MgO thin film. However, any suitable material can be used for the protective coating, such as those listed in co-pending application Ser. No. 11/432,143, entitled “Plasma Display Panel with Low Voltage Material,” filed on May 11, 2006, and incorporated herein by reference.
In the embodiment of FIG. 5, the dielectric stand 519 is located in the center of the sustain gap 530, with a length slightly less than that of the sustain gap 530 and its width close to the width of phosphor channel 520 (or 521, 522) on the back plate 515. In the preferred embodiment, the length of the dielectric stand 519 is about 20 micrometers less than the length of sustain gap 530. The distance between the width of the dielectric stand 519 and the wall of the phosphor channels 520, 521, or 522 is preferably about 10 micrometers or less on each side.
The height of the ribs that define the sub-pixels in the back plate should be adjusted to accommodate the dielectric stand on the front plate. The higher rib height can also increase the phosphor area to further enhance the brightness of the panel. The height of the dielectric stand 519 can be varied significantly, but is preferably between about 20 micrometers and about 300 micrometers. The depth of rib 518 on glass back plate 515 should be adjusted according to the height of the dielectric stand 519, so that the gap between the top of dielectric stand 519 and the bottom of phosphor channel 520, 521, or 522 is between about 50 micrometers and 200 micrometers. Preferably, the gap is about 100 micrometers.
The length of the dielectric stand 519 can also vary from a size longer than sustain gap 530, such as about 100 micrometers longer than the sustain gap 530, to approximately 20 micrometers in overall length. Some of these embodiments are shown in FIGS. 6, 7, and 8. Referring to FIG. 6, a dielectric stand 619 that is slightly larger than sustain gap 630 is shown. Referring to FIG. 7, a dielectric stand 719 that is the same size as sustain gap 730 is shown. Referring to FIG. 8, a dielectric stand 819 that is smaller than the sustain gap 830 is shown.
The dielectric stand of the present disclosure can also be placed off-center of the sustain gap, as is illustrated by dielectric stand 919 of FIG. 9.
The shape of the dielectric stand can also vary from a rectangular shape to other shapes shown in FIGS. 10 though 14. These shapes include the trapezoidal shaped dielectric stands 1019, 1119, and 1219 of FIGS. 10, and 11, 12, respectively, the triangular shaped stand 1319 of FIG. 13, or the semi-circular shaped stand 1419 of FIG. 14.
Referring to FIG. 15, another embodiment of the present disclosure is shown. Dielectric stand 1519 of the shown embodiment is a continuous strip that is placed on top of dielectric layer 1513 and runs across phosphor channels 1520, 1521, and 1522, as opposed to the stands of previous embodiments that only occupy one phosphor channel at a time. Back glass plate 1510 and dielectric layer 1513 also have back rib 1540 connected thereto, which blocks the discharge path from crossing over into other sub-pixels. Dielectric stand 1519 is advantageous in that it is easier to manufacture and assemble. However, due to the fact that the phosphor channels 1520, 1521, and 1522 are not isolated from each other in this embodiment, there will be some interference or “cross-talk” between the channels that will affect the image quality of the panel as a whole. Barrier walls around the sub-pixel, however, can prevent “cross-talk” between neighboring sub-pixels in both the horizontal and vertical directions. The height of dielectric stand 1519 can be between about 20 micrometers and about 1000 micrometers. Referring to FIG. 16, dielectric stand 1619 is shown, which is substantially similar to dielectric stand 1519, with the exception that it is rectangularly shaped. In both of the embodiments shown in FIGS. 15 and 16, the dielectric stands are coated with a protective layer, for example with a layer made of MgO.
Referring to FIG. 17, another embodiment of the present disclosure is shown, and has dielectric stand 1719, sustain electrode 1711, and scan electrode 1712, which are similar to sustain electrode 511 and scan electrode 512 of FIG. 5, respectively. In this embodiment, an additional electrode 1750 is embedded inside dielectric stand 1719. There can be one or more electrodes 1750 located inside dielectric stand 1719, and these electrodes 1750 can also be located anywhere within dielectric stand 1719. The electrodes 1750 can be utilized to force the discharge path around dielectric stand 1719, thus maximizing the length of the path. Preferably, the additional electrode is made of transparent conducting material such as Indium Tin Oxide.
The transparent dielectric stands or steps of the present disclosure are formed by a photolithographic process. Photosensitive transparent dielectric tape or thick film is laminated or screen printed on top of a normal dielectric layer or directly on glass with pre-patterned metal electrode lines. A photolithographic process is used to pattern the transparent layer, and as a result the dielectric stand or steps can be created. One or more layers of photosensitive transparent dielectric tape can be applied for creating thick dielectric stands or steps.
Table 1 below shows a luminous efficacy comparison between a conventional PDP, and PDPs with the dielectric stand structures of the present disclosure. The “Panel with dielectric stand-1” structure is very similar to the PDP structure shown in FIG. 7, namely one where the dielectric stand is the same length as the sustain gap. This dielectric stand is 20 micrometers thick, made of transparent dielectric material, and made by the photolithographic process described above. The “Panel with dielectric stand-2” PDP is similar to the “Panel with dielectric stand-1” PDP, with the exception that the dielectric stand is 20 micrometers longer than the sustain gap of the PDP. This is similar to the embodiment shown in FIG. 6.
The “Panel with dielectric stand-1” PDP has a luminous efficacy of 1.97 (Lum/W), about 23% higher than the luminous efficacy of the PDP without the dielectric stand. The gas mixture in the panel is Neon with 15% Xenon, at operating voltage of 155V. The luminous efficacy of the “Panel with dielectric stand-2” PDP is 1.89 Lum/W, 18% higher than the efficiency of the conventional PDP without the dielectric stand. The operating voltage of the PDP of the present disclosure structure is almost the same as a conventional PDP. Conventional PDPs can operate at an approximate voltage of 155V, and the PDPs of the present disclosure vary by only approximately 2 volts. These results clearly demonstrate that the PDPs of the present disclosure, which include a dielectric stand, can significantly increase the luminous efficacy of the PDP without significantly increasing the operating voltage. The improved luminous efficacy of the PDPs of the present disclosure is not limited to the data shown in Table 1, as this is merely one specific example.
The present disclosure has been described with particular reference to the preferred embodiments. It should be understood that the foregoing descriptions and examples are only illustrative of the invention. Various alternatives and modifications thereof can be devised by those skilled in the art without departing from the spirit and scope of the present disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications, and variations that fall within the scope of the appended claims.
Patent Application
20080061698
