1. Field of the Invention
The present embodiments relate to a plasma display panel (PDP) used for a plasma display device, and more particularly, to a PDP that improves both contrast and discharge efficiency by reducing residual images and reflection of external light.
2. Description of the Related Art
FIG. 1 is a fragmentary perspective view of a conventional PDP as disclosed in Japanese Patent Laid-Open Publication No. 1998-172442.
As shown in FIG. 1, the conventional PDP includes an upper panel 1 and a lower panel 2, which are bonded to each other, and a space defined by the upper and lower panels 1 and 2 is filled with a discharge gas. The upper panel 1 includes a front substrate 60, pairs of sustain discharge electrodes 84, and a front dielectric layer 80. Each of the pairs of sustain discharge electrodes 84 include a Y-electrode 83 and an X-electrode 82, which are disposed on a bottom surface 60a of the front substrate 60. The pairs of sustain discharge electrodes 84 are covered with the front dielectric layer 80. The front dielectric layer 80 may be covered with a protective layer 90 that is typically formed of MgO. Meanwhile, the Y-electrode 83 includes a first transparent electrode 83b, which is formed of indium tin oxide (ITO), and a first bus electrode 83a, which prevents a voltage drop in the first transparent electrode 83b. Like the Y-electrode 83, the X-electrode 82 includes a second transparent electrode 82b and a second bus electrode 82a. 
The lower panel 2 includes a rear substrate 10, address electrodes 20, a rear dielectric layer 30, barrier ribs 40, and phosphor layers 50. The address electrodes 20 are disposed on a top surface of the rear substrate 10 and intersect the pairs of sustain discharge electrodes 84. The address electrodes 20 are covered with the rear dielectric layer 30. The barrier ribs 40 are disposed on the rear dielectric layer 30 and define discharge cells along with the pairs of sustain discharge electrodes 84. The phosphor layers 50 are coated on inner surfaces of the discharge cells.
For the above-described conventional PDP, a discharge cell is selected due to address discharge induced between the address electrode 20 and the Y-electrode 83. Then, sustain discharge arises between the X-electrode 82 and the Y-electrode 83 of the selected discharge cell, so that the discharge cell emits light. More specifically, as the sustain discharge happens, the discharge gas filled in the discharge cell emits ultraviolet rays, which lead the phosphor layers 50 to emit red, green, and blue visible rays, thus producing the image of the PDP.
In the conventional PDP having the above-described construction, external light is projected on a front surface of a display region of the PDP. Owing to this reflection of external light, the PDP has higher reflection brightness and a lower contrast.
Therefore, it has become increasingly necessary to cut off the reflection of external light in order to minimize an elevation in the reflection brightness of the PDP and improve the contrast thereof.
FIG. 3 is a diagram for schematically explaining the principles of additive mixture of colors and subtractive mixture of colors.
As shown in FIG. 3, when the three primary colors of light, that is, red, green, and blue colors, are mixed using the additive mixture of colors, a central portion in which all the three colors are mixed emits white light, and portions in which two of the three colors are mixed emit yellow, azure, and violet light, respectively. Here, it is said that two colors disposed opposite each other across a white color are complementary to each other. In mixing the complementary colors, the mixed color lowers in both brightness and chroma and, preferably, becomes a black color.
When yellow, azure, and violet colors are mixed using the subtractive mixture of colors, a central portion in which all the three colors are mixed takes on a black color, and portions in which two of the three colors are mixed take on red, green, and blue colors, respectively. For example, when the red and azure colors, which are complementary to each other, are mixed, the mixed color lowers in both brightness and chroma. Therefore, by making use of complementary colors as described above, it is expected that there will be improvements in contrast and other problems.