# Patent

## Title
Plasma display panel using color filters to improve contrast

## Abstract

A plasma display panel is provided. The plasma display panel includes a front substrate, an X electrode and a Y electrode alternately formed on the front substrate, a dielectric layer formed to cover the X and Y electrodes, a rear substrate installed to face the front substrate, address electrodes formed on the rear substrate and intersecting the X and Y electrodes, barrier ribs formed between the front and rear substrates, and red, green, and blue fluorescent layers applied in discharge cells defined by the barrier ribs. The dielectric layer and the barrier ribs are colored with two complementary colors that essentially filter out nearly all light. Accordingly, it is possible to reduce outdoor daylight reflection and improve image contrast by an improved design over the use of black stripes.

## Background
CLAIM OF PRIORITY
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 18 Aug. 2003 and there duly assigned Serial No. 2003-56849.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma display panel (PDP), and more particularly, to a PDP which reduces the brightness of outdoor daylight reflection using a complementary color relationship between a dielectric layer and barrier rib as opposed to using black stripes.
2. Description of the Related Art
In general, a plasma display panel (PDP) displays numbers, characters, or graphics by injecting discharge gas between two substrates with a plurality of electrodes, sealing the two substrates, applying a discharge voltage to the plurality of electrodes, and applying a pulse voltage to address a point where two electrodes intersect when gas is emitted due to the application of the discharge voltage.
A PDP is classified into a direct current (DC) type and an alternate current (AC) type, according to the type of driving voltage applied to a discharge cell, i.e., according to the type of discharge. Also, the plasma display panels maybe classified into an opposite discharge type and a surface discharge type according to a configuration of electrodes.
In order to improve image contrast and to reduce the amount of external light reflected off the display, a black matrix layer or a black stripe is added. However, the use of such a black stripe can only go so far in improving image contrast and reducing externally reflected light. What is needed is an improved design for improving image contrast and reducing externally reflected light.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved plasma display panel.
It is also an object of the present invention to provide an improved way for improving image contrast and reduce externally reflected light over the use of black stripes or black matrices.
It is also an object of the present invention to provide a method of making the novel plasma display panel of the present invention.
It is also an object of the present invention to provide for another design for a plasma display panel that prevents the external reflection of light and improves contrast without using black stripes.
These and other objects can be achieved by a plasma display panel that reduces outdoor daylight reflection using the complementary color relationship between a dielectric layer of a front substrate and barrier ribs of a rear substrate.
According to an aspect of the present invention, there is provided a plasma display panel with a front substrate, an X electrode and a Y electrode alternately formed on the front substrate, a dielectric layer formed to cover the X and Y electrodes, a rear substrate installed to face the front substrate, address electrodes formed on the rear substrate and intersecting the X and Y electrodes, barrier ribs formed between the front and rear substrates, and red, green, and blue fluorescent layers applied in discharge cells defined by the barrier ribs. The dielectric layer and the barrier ribs are colored to subtractively filter out one color each of light. The dielectric layer and the barrier ribs are colored with complementary colors using subtractive mixing such that the resultant transmitted light is almost black. Thus, this subtractive mixing of the dielectric layer and the barrier rib is used instead of a black stripe layer to improve image contrast and to reduce the reflection of external light.
According to another aspect of the present invention, there is provided a plasma display panel with a front substrate, an X electrode and a Y electrode alternately arranged on the front substrate, a dielectric layer covering the X and Y electrodes and having a first color, a rear substrate installed to face the front substrate, address electrodes formed on the rear substrate and intersecting the X and Y electrodes, barrier ribs formed between the front and rear substrates and having a second color, and red, green, and blue fluorescent layers applied in discharge cells defined by the barrier ribs. Portions corresponding to the barrier ribs and the dielectric layer have a third color obtained by performing subtractive mixing by subtracting out first and second colors from incoming light. The dielectric layer with the first color and the barrier ribs with the second color form a complementary color relationship.
According to another aspect of the present invention, there is provided a plasma display panel that includes a front substrate, a rear substrate arranged to face the front substrate, a dielectric layer arranged between the front and the rear substrates, at least a portion of the dielectric layer having a first color, the first color being a chromatic color and a plurality of barrier ribs arranged between the front and the rear substrates, all of the plurality of barrier ribs having a second color, the second color being a chromatic color and being different from the first color. The first color and the second color can be complementary colors with respect to each other. A portion of the dielectric layer that overlaps with the plurality of barrier ribs can appear as a third color that is darker than each of the first and the second colors. The third color can be near black. A brightness of the first color can be higher than a brightness of the second color. An entirety of the dielectric layer can be colored. Only upper portions of the plurality of barrier ribs can be colored. An entirety of the plurality of barrier ribs can be colored. The dielectric layer can be arranged between the front substrate and the plurality of barrier ribs. The plasma display panel can further include a plurality of X electrodes and a plurality of Y electrodes, each being arranged on the front substrate and each being covered by the dielectric layer. Ones of the plurality of X electrodes and ones of the plurality of Y electrodes can be alternately arranged. The plasma display panel can also include a plurality of address electrodes arranged between the front and the rear substrates and intersecting the plurality of X electrodes and the plurality of Y electrodes a plurality of fluorescent layers arranged within a plurality of discharge cells defined by the plurality of barrier ribs. Each X electrode can include a first transparent electrode and a first bus electrode electrically connected to the first transparent electrode, and each Y electrode can include a second transparent electrode and a second bus electrode electrically connected to the second transparent electrode. Each X electrode can also include a first project electrode that is transparent and extends from the first transparent electrode toward the second transparent electrode and each Y electrode can also include a second project electrode that is transparent and extends from the second transparent electrode toward the first transparent electrode. Each first transparent electrode and each second transparent electrode can include indium tin oxide. Each first bus electrode and each second bus electrode can include one of Ag, Cr, Cu or Al. The plurality of barrier ribs can be of a matrix type.
According to yet another aspect of the present invention, there is provided a plasma display panel that includes a front substrate, a rear substrate arranged to face the front substrate, a dielectric layer arranged between the front and the rear substrates, at least a portion of the dielectric layer is of a first color and a plurality of barrier ribs arranged between the front and the rear substrates, at least a portion of the plurality of barrier ribs is of a second color, wherein the first color and the second color are subtractive-mixed with each other. The first color and the second color can be complementary colors with respect to each other. A portion of the dielectric layer that overlaps with the plurality of barrier ribs can appear as a third color that is darker than each of the first and the second colors. The third color can be near black. A brightness of the first color can be higher than a brightness of the second color. An entirety of the dielectric layer can be colored. Only upper portions of the plurality of barrier ribs can be colored. An entirety of the plurality of barrier ribs can be colored. The dielectric layer can be arranged between the front substrate and the plurality of barrier ribs. The plasma display panel can also include a plurality of X electrodes and plurality of Y electrodes, each being arranged on the front substrate and each being covered by the dielectric layer. Ones of the plurality of X electrodes and ones of the plurality of Y electrodes can be alternately arranged. The plasma display panel can also include a plurality of address electrodes arranged between the front and the rear substrates and intersecting the plurality of X electrodes and the plurality of Y electrodes and a plurality of fluorescent layers arranged within a plurality of discharge cells defined by the plurality of barrier ribs. Each X electrode can include a first transparent electrode and a first bus electrode electrically connected to the first transparent electrode, and each Y electrode can include a second transparent electrode and a second bus electrode electrically connected to the second transparent electrode. Each X electrode can also include a first project electrode that is transparent and extends from the first transparent electrode toward the second transparent electrode and each Y electrode can also include a second project electrode that is transparent and extends from the second transparent electrode toward the first transparent electrode. Each first transparent electrode and each second transparent electrode can include indium tin oxide. Each first bus electrode and each second bus electrode can include a material such as Ag, Cr, Cu or Al. The plurality of barrier ribs can be of a matrix type.



BRIEF DESCRIPTION OF THE DRAWINGS
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:
FIG. 1 is a cross-sectional view of a unit cell of a plasma display panel (PDP);
FIG. 2 is a plan view of a PDP;
FIG. 3 is a plan view of a type of PDP;
FIG. 4 is a plan view of another type of PDP;
FIG. 5 is a plan view of yet another type of PDP;
FIG. 6 is an exploded perspective view of a PDP according to an embodiment of the present invention;
FIG. 7 is a plan view of the PDP of FIG. 6;
FIG. 8 illustrates a color wheel for a RGBCYM color scheme; and
FIG. 9 illustrates a color wheel for a RYB and OGV color scheme that produces complementary color pairs that filter out nearly all light.



DETAILED DESCRIPTION OF THE INVENTION
Turning now to the figures, FIG. 1 is a cross-sectional view of a unit cell of a PDP 10. Referring to FIG. 1, the PDP 10 includes a pair of sustaining electrodes 12 on a front substrate 11 and a front dielectric layer 13 covering the pair of sustaining electrodes 12. A surface of the front dielectric layer 13 is coated with a protective layer 14.
Address electrodes 16 are formed on a rear substrate 15 installed to face the front substrate 11, a rear dielectric layer 17 is formed on the address electrodes 16, barrier ribs 18 are formed on the rear dielectric layer 17, and red, green, and blue fluorescent layers 19 are formed to cover an upper surface of the rear dielectric layer 17 and inner sidewalls of the barrier ribs 18. The front substrate 11 is combined with the rear substrate 15, an inert gas is injected into an inner gap between the front and rear substrates 11 and 15, thus forming a discharge region 100 therebetween.
An operation of the PDP 10 with the above structure will now be briefly described. When a driving voltage is applied to the sustaining electrodes 12, surface discharging is caused on the front dielectric layer 13 and the protective layer 14, thus generating ultraviolet rays. The ultraviolet rays excite a fluorescent material of the fluorescent layer 19, thus displaying colors.
More specifically, the application of the driving voltage accelerates space charges contained in the discharge cell, the accelerated space charges collide against penning mixture gas contained in the discharge cell at 400–500 Torr of pressure. The penning mixture gas is obtained by adding helium (He) and xenon (Xe) to neon (Ne) that is a main ingredient of the penning mixture gas.
The collision excites the inert gas, thus generating ultraviolet rays of 147 nanometers. The generated ultraviolet rays collide against the fluorescent material of the fluorescent layer 19 coated onto the address electrode 16 and the barrier ribs 18, thus generating visible rays.
FIG. 2 illustrates plan view of a PDP 20. Referring to FIG. 2, plural pairs of bus electrodes 21 are arranged in stripes on a front substrate of the PDP 20 at predetermined intervals, and black stripes 22 are positioned in non-discharge regions between the respective pairs of the bus electrodes 21. The bus electrodes 21 and the black stripes 22 are covered with a transparent dielectric layer 23. Also, matrix type barrier ribs 24 are formed on a rear substrate of the PDP 20. The barrier ribs 24 are white and their horizontal barrier ribs 24a are arranged to overlap with the respective black stripes 22 when the front and rear substrates are combined.
FIG. 3 illustrates a plan view of another type of a PDP 30. Referring to FIG. 3, plural pairs of bus electrodes 31 are arranged in stripes on a front substrate of the PDP 30 at predetermined intervals, and black stripes 32 are positioned in non-discharge regions between the respective pairs of the bus electrodes 31. The bus electrodes 31 and the black stripes 32 are covered with a transparent dielectric layer 33. Also, matrix type barrier ribs 34 are formed on a rear substrate of the PDP 30. The barrier ribs 34 are white and horizontal barrier ribs 34a are formed to overlap with the respective black stripes 32 when the front and rear substrates are combined. Red, green, and blue filters 35R, 35G, and 35B are arranged perpendicularly to the bus electrodes 31.
FIG. 4 illustrates characterization portions of yet another type of PDP 40. Referring to FIG. 4, plural pairs of bus electrodes 41 are arranged in stripes on a front substrate of the PDP 40 at predetermined intervals, and black stripes 42 are positioned in non-discharge regions between the respective pairs of the bus electrodes 41. The bus electrodes 41 and the black stripes 42 are covered with a colored dielectric layer 43. Also, matrix type barrier ribs 44 are formed on a rear substrate of the PDP 40. The barrier ribs 44 are white and their horizontal barrier ribs 44a are formed to overlap with the respective black stripes 42 when the front and rear substrates are combined.
FIG. 5 illustrates a plan view of still another type of PDP 50. Referring to FIG. 5, plural pairs of bus electrodes 51 are arranged in stripes on a front substrate of the PDP 50 at predetermined intervals, and black stripes 52 are positioned in non-discharge regions between the respective pairs of the bus electrodes 51. The bus electrodes 51 and the black stripes 52 are covered with a transparent dielectric layer 53. Also, matrix type barrier ribs 54 are formed on a rear substrate of the PDP 50. The barrier ribs 54 are black and horizontal barrier ribs 54a are formed to overlap with the respective black stripes 52 when the front and rear substrates are combined.
A PDP such as that shown in FIGS. 2 through 5 have the following disadvantages. First, in these PDPs, opaque bus electrodes and black stripes are patterned to reduce outdoor daylight reflection and improve contrast. However, application of the black stripes is limited to non-discharge regions, thus change of location of the bus electrodes is limited. Second, installation of red, green, and blue filters in red, green, and blue discharge cell is further required to increase degree of color purity. Third, when using only a dielectric layer to reduce the outdoor daylight reflection, a rate of reducing the outdoor daylight reflection is limited. Fourth, a PDP adopts barrier ribs with black upper sides for reducing the brightness of reflection, but use of such barrier ribs substantially reduces the brightness of reflection by 10 or more percentages.
Referring to FIG. 6, a plasma display panel (PDP) 60 according to an embodiment of the present invention is illustrated and includes a front substrate 61 and a rear substrate 610 which is disposed to face the front substrate 61. X electrodes 63 and Y electrodes 64 are alternately arranged at the bottom of the front substrate 61 along an x-direction on the front substrate 61. The X electrode 63 includes a first transparent electrode 63a and a stripe type first bus electrode 63b formed along an edge of the first transparent electrode 63a. Similarly, the Y electrode 64 includes a second transparent electrode 64a and a stripe type second bus electrode 64b formed along an edge of the second transparent electrode 64a. 
The first and second transparent electrodes 63a and 64a are formed of a transparent conductive film such as an Indium Tin Oxide (ITO) film. The first and second bus electrodes 63b and 64b are formed of a metal material with high electrical conductivity such as Ag paste, Cr—Cu—Cr, or Al.
A pair of the X and Y electrodes 63 and 64 are positioned in each discharge cells A predetermined sized first projected electrode 63c is extended to an inner wall of the first transparent electrode 63a, projecting in a discharge cell toward the second transparent electrode 64a. A predetermined sized second project electrode 64c is extended to an inner wall of the second transparent electrode 64a, projecting in a discharge cell toward the first transparent electrode 63a. 
The shapes of the X and Y electrodes 63 and 64 or their arrangements in a discharge cell are not limited to the above description. In other words, when the X and Y electrodes 63 and 64 are arranged to face each other, their shapes or arrangements may be variously determined. In this disclosure, a region between a pair of the X and Y electrodes 63 and 64 and another pair of the X and Y electrodes 63 and 64 will be referred to as Non-Discharge (ND) region.
A front dielectric layer 66 is formed on a base of the front substrate 61 to cover the X and Y electrodes 63 and 64. An upper surface of the front substrate 61 is completely coated with the front dielectric layer 66. A surface of the front dielectric layer 66 is coated with a protective layer 67 such as a magnesium oxide.
Address electrodes 620 are formed on the rear substrate 610 at predetermined intervals and run in the y-direction orthogonal to the X electrodes 63 and the Y-electrodes 64. Also, the address electrodes 620 are arranged to intersect the X and Y electrodes 63 and 64. A rear dielectric layer 630 is formed on the address electrodes 620 to cover the address electrodes 620.
Barrier ribs 640 are disposed on the rear dielectric layer 630 to define discharge cells and prevent crosstalk between discharge cells. The barrier ribs 640 include first barrier ribs 650 formed in the x-direction perpendicular to the address electrodes 620 and second ribs 660 formed in the y-direction parallel with the address electrodes 620. The second ribs 660 are extended to both sides of the first barrier ribs 650, thus forming a matrix structure. However, if the discharge cells are defined by the barrier ribs 640, the barrier ribs 640 are not limited to the illustrated matrix structure. Alternatively, the barrier ribs 640 may be formed as a meander type, a honeycomb type, a delta type, or a stripe type. An upper portion of the rear dielectric layer 630 and inner sidewalls of the barrier ribs 640, which form the discharge cells, are covered with red, green, and blue fluorescent layers 670. A PDP, such as the PDP 60 according to the present invention is capable of reducing the brightness of outdoor daylight reflection without using black stripes, but instead using a complementary color relationship between a dielectric layer 66 and barrier ribs 640 based on subtractive mixing.
More specifically, as shown in FIG. 7 illustrating characterization portions of the PDP 60 of FIG. 6, the X and Y electrodes 63 and 64 are disposed at a rear side of the front substrate 61 of FIG. 6. The X and Y electrodes 63 and 64 are covered with the front dielectric layer 66. The matrix-type barrier ribs 640 are disposed on the rear substrate 610. The first barrier ribs 650 are arranged in parallel with the X and Y electrodes 63 and 64, and the second barrier ribs 660 are arranged perpendicularly to the X and Y electrodes 63 and 64.
Black stripes of a PDP are not formed in ND regions of the PDP 60. Instead, the front dielectric layer 66 and the barrier ribs 640 are colored using subtractive mixing. Therefore, the colors of portions corresponding to the front dielectric layer 66 and the barrier ribs 640 are darker than those of other portions. That is, the colors of the corresponding portions are near black.
In the color display art, all colors can be made out of a combination of additive primaries red, green and blue (R), (G) and (B). Alternatively, the colors can be made out of the subtractive primaries of magenta, yellow and cyan (M), (Y) and (C). The subtractive primaries can be formed by adding together two different additive primaries. For example, (R) plus (G) results in (Y), (B) plus (G) results in (C) and (B) plus (R) results in (M). Similarly, the additive primaries can be derived by mixing together two subtractive primaries. (R) can be formed by mixing (M) and (Y). (B) can be formed by mixing (M) and (C). (G) can be formed by mixing (Y) and (C). In yet another alternative color scheme, (R), (Y) and (B) are primary colors and orange (O), (G) and violet (V) are the secondary colors.
A color wheel or a color circle can be formed for each of these color schemes. In a clockwise direction, a color wheel as illustrated in FIG. 8 is made out of (R), (M), (B), (C), (G) and (Y). Colors diametrically opposite from each other on the color wheel are called complementary colors. In other words, (R) and (C) are complements of each other, (M) and (G) are complements of each other and (Y) and (B) are complements of each other for the color wheel of FIG. 8.
In another color scheme, the primary colors are (R), (B) and (Y) instead of (R), (B) and (G). Secondary colors are then formed by mixing together two primary colors, thus producing orange (O), violet (V) and green (G). In this alternative color scheme, a color wheel as illustrated in FIG. 9 can be formed by having the colors (R), (0), (Y), (G), (B), and (V) in a clockwise direction. (O) is positioned between (R) and (Y) and is formed by mixing (R) and (Y). Similarly, (G) is positioned between (B) and (Y) and is formed by adding (B) and (Y). (V) is positioned between (R) and (B) and is formed by mixing (R) and (B). As in the color wheel of FIG. 8, colors diametrically opposite from each other on the color wheel of FIG. 9 are considered complements of each other. In this color scheme, (G) is a complement of (R), (O) is a complement of (B), and (V) is a complement of (Y) as each of these pairs of colors resides diametrically opposite from each other on the color wheel. For each of these three complementary pairs in FIG. 9, when mixed, forms essentially black. The present invention exploits this feature of complementary pairs of colors in the color wheel of FIG. 9.
The present invention employs subtractive mixing. In subtractive mixing, a partially transparent filter is used to filter out one color component of impinging light while transmitting the other colors. When two partially transparent filters are placed in series, two color components are filtered out of impinging light and the remainder is transmitted. Typically, when three filters are placed in series, and each of the three filters are a primary color, no light will be transmitted as all of the light is absorbed. Thus, if a (C), (M) and (Y) filter are placed in series, no light is transmitted. Or, if (R), (G) and (B) filters are placed in series, no light is transmitted. The present invention exploits the complementary color scheme of FIG. 9 to produce essentially no transmitted light with the use of just two filters by subtracting out of incoming light just two colors instead of three to form near black.
In the subtractive mixing, a color is produced by subtracting a color element from white incident light. Primary three colors are magenta (M), yellow (Y), and cyan (C), and an achromatic color such as gray or black is obtained by mixing a complementary pair of colors, e.g., mixing red with green or mixing blue with orange or by mixing violet and yellow. In a combination of complementary colors, the respective primary three colors may be matched with their counterparts of complementary colors or various complementary pairs of colors may be selected. Subtractive mixing results in a reduction in the brightness and saturation of the original colors. In detail, mixing of adjacent colors in the color circle of FIG. 9 produces an intermediate color between the adjacent colors, mixing of colors at a long distance in the color circle reduces the brightness and saturation of the original colors, thus producing near-gray, and mixing of complementary colors produces near-black. The subtractive mixing uses absorption, selective transmission, or reflection of light. That is, in general, red, green, and blue are absorbed in the subtractive mixing. The absorption of such colors can be observed by installing filters of various colors along the optical path of a white ray.
Turning back to the novel PDP 60 of the present invention, the front dielectric layer 66 and the barrier ribs 640 are colored using the subtractive mixing. More particularly, upper portions 641 of the barrier ribs 640, shown in FIG. 6, are colored with a high-reflection non-black color, thereby preventing a reduction in the brightness of light emitted from the red, green, and blue fluorescent layers 670 and preventing the light from being lost in the barrier ribs 640. Also, the front dielectric layer 66 is colored with a color that minimizes a reduction in the transmissivity of the emitted light.
Also, the upper portion 641 of the barrier rib 640 and the front dielectric layer 66 are colored with complementary colors from the color wheel of FIG. 9 so as to reduce outdoor daylight reflection, thus improving contrast. For instance, the upper portion 641 may be colored with orange (O) that is a high-reflection color and the front dielectric layer 66 is colored with blue (B) that is a complementary color of orange (O). The brightness of the colored front dielectric layer 66 is higher than that of the colored barrier rib 640. Alternatively, the entire barrier ribs 640 and not just the top portions 641 are colored. In one embodiment, only non-discharge (ND) regions of dielectric layer 66 are colored and the remaining portions of dielectric layer 66 that correspond to discharge cells are transparent. The non-discharge regions essentially correspond to portions of dielectric layer 66 in contact with barrier ribs 640. Alternatively, in another embodiment, the entire dielectric layer 66 is colored, including discharge and non-discharge regions. This later embodiment where the entire dielectric layer 66 is colored is possible because the brightness of the plasma display panel at present is very high and thus it does not matter if portions of dielectric layer 66 that correspond to a discharge regions are colored.
Now, a process for making the PDP 60 will be discussed. In the PDP 60 with the above structure, a raw material for barrier ribs 640 is applied evenly onto the rear substrate 610. In the embodiment where only an upper portion 641 only of barrier ribs 640 is colored, a raw material for transparent barrier ribs is first applied. Then, a raw material for the colored portion 641 of the barrier ribs is applied evenly on top of the raw material for the transparent portion. Both raw material layers of the transparent and the colored portions are sandblasted together in a single sandblasting step. In the embodiment where the entire barrier rib structure is colored, the raw material for the colored barrier ribs only is applied without applying a transparent raw material layer. In either embodiment, after applying all the raw material layers for the barrier ribs, a photosensitive photoresist that is highly resistant to sand blasting is coated onto the rear substrate 610 covered with the raw barrier rib material(s).
Next, a photo mask, which has a pattern corresponding to a desired barrier rib pattern, is disposed on the photoresist-coated upper portion of the material for barrier ribs, and the photoresist is exposed with ultraviolet rays to form the desired barrier rib pattern thereon. The exposed portions of the photoresist are chemically stabilized and developed, thus obtaining the barrier rib pattern, upper portions of which are colored.
Next, an abrasive is sprayed onto a resultant structure via a nozzle of a sand blast apparatus containing the abrasive, under a high pressure. Then, portions of the material for barrier ribs, which are not attached with the photoresist, are removed from the resultant structure due to the force of spraying the abrasive. Thereafter, the photoresist is peeled off from the resultant structure, and the remaining material for barrier ribs are sintered thus completing the barrier ribs 640.
As described above, a PDP according to the present invention has the following advantages. First, a dielectric layer and barrier ribs are colored with complementary colors using subtractive mixing, thus reducing the brightness of outdoor daylight reflection and improving contrast without forming black stripes in non-discharge regions. Second, the present invention allows a user to combine colors of a front substrate and a dielectric layer as the user desires. Third, barrier ribs are colored with a high-reflection color, thereby preventing loss of light emitted from the red, green, and blue fluorescent layers. Fourth, since the present invention adopts matrix-type barrier ribs, it is possible to use portions of non-discharge regions, which are greater than those of the non-discharge regions assumed by the black stripes, for reducing outdoor daylight reflection, thereby improving contrast. Fifth, it is possible to reduce outdoor daylight reflection by coloring the front substrate with colored barrier ribs using subtractive mixing while increasing the transmissivity of a dielectric layer formed on the front substrate. Accordingly, the present invention provides a PDP in which a dielectric layer and barrier ribs are colored with complementary colors using subtractive mixing principle, thereby reducing outdoor daylight reflection and improving contrast.
While this invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

## Claims

1. A plasma display panel, comprising:
a front substrate;
an X electrode and a Y electrode alternately arranged on the front substrate;
a dielectric layer arranged to cover the X and Y electrodes;
a rear substrate arranged to face the front substrate;
address electrodes arranged on the rear substrate and intersecting the X and Y electrodes;
barrier ribs arranged between the front and rear substrates; and
red, green, and blue fluorescent layers arranged in discharge cells defined by the barrier ribs, wherein the dielectric layer and the barrier ribs are colored with complementary colors.

2. The plasma display panel of claim 1, the dielectric layer and the barrier ribs being colored with complementary colors using subtractive mixing.

3. The plasma display panel of claim 2, wherein only upper portions of the barrier ribs are colored.

4. The plasma display panel of claim 2, wherein an entire portion of the barrier ribs is colored.

5. The plasma display panel of claim 1, wherein the X electrode comprises a first transparent electrode and a first bus electrode electrically connected to the first transparent electrode, and the Y electrode comprises a second transparent electrode and a second bus electrode electrically connected to the second transparent electrode.

6. The plasma display panel of claim 5, the X electrode comprises a first project electrode that is transparent and extends sideways from the first transparent electrode, the first project electrode projecting into a discharge cell and towards the second transparent electrode; and
the Y electrode comprises a second project electrode that is transparent and extends sideways from the second transparent electrode, the second project electrode projecting into a discharge cell and towards the first transparent electrode.

7. The plasma display panel of claim 5, wherein the first and second transparent electrodes are each comprised of indium tin oxide films.

8. The plasma display panel of claim 5, wherein the first and second bus electrodes are comprised of at least one metal material selected from the group consisting of Ag, Cr, Cu, and Al.

9. The plasma display panel of claim 1, wherein the barrier ribs comprise:
a first barrier rib arranged in parallel with the X and Y electrodes; and
a second barrier rib arranged perpendicular to the X and Y electrodes,
wherein the first and second barrier ribs are a matrix type.

10. A plasma display panel, comprising:
a front substrate;
an X electrode and a Y electrode alternately arranged on the front substrate;
a dielectric layer covering the X and Y electrodes and having a first color;
a rear substrate arranged to face the front substrate;
address electrodes arranged on the rear substrate and intersecting the X and Y electrodes;
barrier ribs arranged between the front and rear substrates and having a second and different color; and
red, green, and blue fluorescent layers arranged in discharge cells defined by the barrier ribs, each of the first color and the second color being selected from the group consisting of red, violet, blue, green, yellow and orange.

11. The plasma display panel of claim 10, wherein the dielectric layer with the first color and the barrier ribs with the second color are complementary colors of each other.

12. The plasma display panel of claim 10, wherein subtractive mixing of the first color and the second color results in near black.

13. The plasma display panel of claim 10, wherein a brightness of the dielectric layer of the first color is higher than a brightness of the barrier ribs of the second color.

14. The plasma display panel of claim 13, wherein the barrier ribs are highly reflective.

15. The plasma display panel of claim 10, the dielectric layer being entirely colored.

16. The plasma display panel of claim 10, wherein only upper portions of the barrier ribs are colored.

17. The plasma display panel of claim 10, wherein an entire barrier ribs are colored.

18. The plasma display panel of claim 10, wherein only portions of the dielectric layer contacting the barrier ribs are colored with said first color.

19. A plasma display panel, comprising:
a front substrate;
an X electrode and a Y electrode alternately arranged in pairs on the front substrate; a dielectric layer arranged to cover the X and Y electrodes;
a rear substrate arranged to face the front substrate;
address electrodes arranged on the rear substrate orthogonal to the X and Y electrodes;
barrier ribs arranged between the front and rear substrates; and
red, green, and blue fluorescent layers arranged in discharge cells defined by the barrier ribs, the dielectric layer made out of an optically semi-transparent material that filters out only a first color of light from an incoming beam, the barrier ribs being made out of an optically semi-transparent material that filters out only a second color of light from an incoming beam.

20. The plasma display panel of claim 19, the first and the second colors being complementary colors of each other.

21. The plasma display of claim 19, the first color being blue and the second color being orange.

22. A plasma display panel, comprising:
a front substrate;
a rear substrate arranged to face the front substrate;
a dielectric layer arranged between the front and the rear substrates, at least a portion of the dielectric layer is of a first color; and
a plurality of barrier ribs arranged between the front and the rear substrates, an entirety of the plurality of barrier ribs is of a second color, wherein the first color and the second color are subtractive-mixed with each other.

23. The plasma display panel of claim 22, wherein the first color and the second color are complementary colors with respect to each other.

24. The plasma display panel of claim 22, wherein a portion of the dielectric layer that overlaps with the plurality of barrier ribs appears as a third color that is darker than each of the first and the second colors.

25. The plasma display panel of claim 24, wherein the third color is near black.

26. The plasma display panel of claim 22, wherein a brightness of the first color is higher than a brightness of the second color.

27. The plasma display panel of claim 22, wherein an entirety of the dielectric layer is colored.

28. The plasma display panel of claim 22, wherein the dielectric layer is arranged between the front substrate and the plurality of barrier ribs.

29. The plasma display panel of claim 22, further comprising a plurality of X electrodes and plurality of Y electrodes, each being arranged on the front substrate and each being covered by the dielectric layer.

30. The plasma display panel of claim 29, wherein ones of the plurality of X electrodes and ones of the plurality of Y electrodes are alternately arranged.

31. The plasma display panel of claim 29, further comprising:
a plurality of address electrodes arranged between the front and the rear substrates and intersecting the plurality of X electrodes and the plurality of Y electrodes; and
a plurality of fluorescent layers arranged within a plurality of discharge cells defined by the plurality of barrier ribs.

32. The plasma display panel of claim 29, wherein each X electrode comprises a first transparent electrode and a first bus electrode electrically connected to the first transparent electrode, and each Y electrode comprises a second transparent electrode and a second bus electrode electrically connected to the second transparent electrode.

33. The plasma display panel of claim 32, wherein each X electrode further comprises a first project electrode that is transparent and extends from the first transparent electrode toward the second transparent electrode; and
each Y electrode further comprises a second project electrode that is transparent and extends from the second transparent electrode toward the first transparent electrode.

34. The plasma display panel of claim 32, wherein each first transparent electrode and each second transparent electrode comprises indium tin oxide.

35. The plasma display panel of claim 32, wherein each first bus electrode and each second bus electrode comprises a material selected from the group consisting of Ag, Cr, Cu and Al.

36. The plasma display panel of claim 22, wherein the plurality of barrier ribs are of a matrix type.

37. A plasma display panel, comprising:
a front substrate;
a rear substrate arranged to face the front substrate;
a dielectric layer arranged between the front and the rear substrates, at least a portion of the dielectric layer having a first color, the first color being a chromatic color; and
a plurality of barrier ribs arranged between the front and the rear substrates, at least a portion of the plurality of barrier ribs having a second color, the second color being a chromatic color and being different from the first color.

38. The plasma display panel of claim 37, wherein the first color and the second color are complementary colors with respect to each other.

39. The plasma display panel of claim 37, wherein a portion of the dielectric layer that overlaps with the plurality of barrier ribs appears as a third color that is darker than each of the first and the second colors.

40. The plasma display panel of claim 38, wherein the third color is near black.

41. The plasma display panel of claim 37, wherein a brightness of the first color is greater than a brightness of the second color.

42. The plasma display panel of claim 37, wherein an entirety of the dielectric layer is colored.

43. The plasma display panel of claim 37, wherein only upper portions of the plurality of barrier ribs are colored.

44. The plasma display panel of claim 37, wherein an entirety of the plurality of barrier ribs is colored.

45. The plasma display panel of claim 37, wherein the dielectric layer is arranged between the front substrate and the plurality of barrier ribs.

46. The plasma display panel of claim 37, further comprising a plurality of X electrodes and a plurality of Y electrodes, each being arranged on the front substrate and each being covered by the dielectric layer.

47. The plasma display panel of claim 46, wherein ones of the plurality of X electrodes and ones of the plurality of Y electrodes are alternately arranged.

48. The plasma display panel of claim 46, further comprising:
a plurality of address electrodes arranged between the front and the rear substrates and intersecting the plurality of X electrodes and the plurality of Y electrodes; and
a plurality of fluorescent layers arranged within a plurality of discharge cells defined by the plurality of barrier ribs.

49. The plasma display panel of claim 46, wherein each X electrode comprises a first transparent electrode and a first bus electrode electrically connected to the first transparent electrode, and each Y electrode comprises a second transparent electrode and a second bus electrode electrically connected to the second transparent electrode.

50. The plasma display panel of claim 49, each X electrode further comprises a first project electrode that is transparent and extends from the first transparent electrode toward the second transparent electrode; and
each Y electrode further comprises a second project electrode that is transparent and extends from the second transparent electrode toward the first transparent electrode.

51. The plasma display panel of claim 49, wherein each first transparent electrode and each second transparent electrode comprises indium tin oxide.

52. The plasma display panel of claim 49, wherein each first bus electrode and each second bus electrode comprises a material selected from the group consisting of Ag, Cr, Cu and Al.

53. The plasma display panel of claim 37, wherein the plurality of barrier ribs are of a matrix type.