KR20080047877A - Plasma display panel - Google Patents

Abstract

A plasma display panel is provided to minimize reduction of brightness by reducing the reflection of external beams through an external beam reflecting layer. A plasma display panel includes first and second substrates(10,20), barrier ribs(16), address electrodes(12), display electrodes, phosphor layers(19), and a filter layer(30). The second substrate is disposed apart from the first substrate and colored. The barrier ribs are disposed between the first and second substrates to define discharge cells(18). The address electrodes are extended along a first direction corresponding to the discharge cells on the first substrate. The display electrodes are extended along a second direction across the first direction on the second substrate corresponding to the discharge cells. The phosphor layers are formed with the same color along the first direction and different colors along the second direction in the discharge cells. The filter layer having at least two type refractive indexes according to the color of the phosphor layers is formed on the second substrate.

Description

Plasma Display Panel {PLASMA DISPLAY PANEL}

1 is a partially exploded perspective view of a plasma display panel according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

FIG. 3 is a cross-sectional view schematically illustrating a relation of visible light refractive index of a dielectric layer, a front substrate, and a filter layer of a plasma display panel according to an exemplary embodiment of the present invention.

FIG. 4 is a diagram illustrating visible light refractive index relationships of a dielectric layer, a front substrate, and a filter layer of a plasma display panel according to an exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10; Back substrate 20; Front board

28; Dielectric layer 30; Filter layer

30a; First region 30b; Second area

30c; Third area

The present invention relates to a plasma display panel, and more particularly, to a plasma display panel which can prevent a display performance degradation of a plasma display panel by improving a structure of a filter layer.

Typically, a plasma display panel is formed of red (R), green (G) and blue (B) generated by exciting a phosphor using vacuum ultraviolet (VUV) emitted from a plasma generated through gas discharge. Implement the image with visible light.

The plasma display panel is classified into a direct current type and an alternating current type according to the applied driving voltage and the structure of the discharge cell. A schematic configuration of an alternating current plasma display panel (hereinafter referred to as a "plasma display panel") will be described. do.

First, address electrodes are formed on a rear substrate, and the address electrodes are covered with a dielectric layer. The partition walls are disposed between the address electrodes on the dielectric layer to form a stripe or matrix shape. The front substrate is spaced apart from the rear substrate so as to face each other, and display electrodes including a pair of sustain electrodes and scan electrodes are formed along a direction crossing the address electrodes. The display electrode is covered with a dielectric layer and a protective film (MgO protective film). A discharge cell is formed at a point where the pair of address electrodes on the rear substrate and the pair of display electrodes on the front substrate cross each other. Phosphor layers of red (R), green (G), and blue (B) are formed inside the discharge cell.

In the above-described plasma display panel, millions of unit discharge cells are arranged in a matrix form, and the visible light is generated by discharging selected discharge cells among the discharge cells to display a necessary image.

In this case, the external light incident on the front surface of the plasma display panel is partially reflected from the front surface of the plasma display panel and mixed with the visible light displayed by the plasma display panel, thereby degrading the display performance of the image actually expressed by the plasma display panel.

In order to solve the above problems, conventionally, a separate black stripe layer is formed on a portion corresponding to the partition wall to reduce reflection of external light due to the front substrate and the dielectric layer.

In addition, the visible light generated in the discharge cells is different in transmittance while refracting and reflecting at the interface between the elements constituting the plasma display panel. For example, when visible light passes through the high-density front substrate and the low-density atmospheric layer, the angle of refraction becomes larger than the incident angle at the boundary portion. Alternatively, total reflection occurs for visible light above the critical angle of incidence.

As a result, there is a problem that the luminance is lowered and the display performance of the image to be actually expressed in the plasma display panel is lowered.

Disclosure of Invention An object of the present invention is to provide a plasma display panel capable of preventing degradation of display performance of a plasma display panel by forming a complementary color layer on elements constituting the plasma display panel, and improving the structure of the filter layer to control visible light refractive index. There is.

In order to achieve the above object, the present invention provides a first substrate, a first substrate and spaced apart from each other, a colored second substrate, a partition wall disposed between the first substrate and the second substrate to partition each discharge cell, An address electrode extending in a first direction corresponding to the discharge cell in the first substrate, a display electrode extending in a second direction crossing the first direction corresponding to the discharge cell in the second substrate, and extending along the second direction A red, green, and blue phosphor layer formed on the discharge cells in the same color along the first direction and repeated in different colors, and a filter layer formed on the outer surface of the second substrate, wherein the filter layer is formed according to the color of the phosphor layer. It is preferable to have at least 2 types of refractive index.

In the above configuration, the filter layer may include a first region corresponding to the red phosphor layer, a second region corresponding to the green phosphor layer, and a third region corresponding to the blue phosphor layer.

The first region, the second region, and the third region may extend in the first direction and may be repeatedly disposed in the second direction.

The first region and the second region have different refractive indices, the second region having a smaller refractive index than the first region.

The first region and the third region have the same refractive index.

The filter layer has a larger refractive index than the front substrate.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. While many specific details are set forth in order to provide a more general understanding of the invention, such as the following description and the annexed drawings, these specific details are illustrated for the purpose of illustrating the invention and are meant to limit the invention to those details. It is not. And a detailed description of known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

1 is a partial exploded attempt of a plasma display panel according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

A configuration of a plasma display panel according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1 and 2.

The plasma display panel is disposed on the front surface of the first substrate 10 (hereinafter referred to as a "back substrate"), the second substrate (hereinafter referred to as a "front substrate"), and the front substrate 20 which are disposed to face each other at a predetermined interval. The filter layer 30 is formed to cover the substrate 20.

The front substrate 20 is formed by coloring the first color. The first color to be colored on the front substrate 20 may have a complementary color relationship with the second color to be colored to other components forming the plasma display panel, and may prevent the display efficiency of the plasma display panel from being degraded by external light reflection. Can be.

In order to implement an image by gas discharge, the plasma display panel displays the address electrode 12 and the address electrode 12 so as to correspond to each discharge cell 18 (18R, 18G, 18B) between the rear substrate 10 and the front substrate 20. The sustain electrode 21 and the scan electrode 22 which form an electrode are provided.

The address electrode 12 extends along the first direction (y-axis direction in the drawing) on the inner surface of the back substrate 10 and continuously corresponds to the discharge cells 18 adjacent in the first direction. . In addition, the plurality of address electrodes 12 are arranged side by side to correspond to adjacent discharge cells 18 in a second direction (the x-axis direction of the drawing) that crosses the first direction. Since the address electrode 12 is disposed on the rear substrate 10 and does not prevent the visible light from being irradiated forward, the address electrode 12 may be formed of an opaque electrode (that is, a metal electrode having excellent conductivity). The address electrode 12 is disposed on the inner surface of the back substrate 10 and covered with the dielectric layer 14. The dielectric layer 14 prevents cations or electrons from directly colliding with the address electrode 12 during discharge, thereby preventing damage to the address electrode 12 and forming and accumulating wall charges.

A partition wall 16 is formed between the back substrate 10 and the front substrate 20. The partition wall 16 is formed at a predetermined height on the dielectric layer 14 to partition the plurality of discharge cells 18. In the discharge cell 18 partitioned through the partition wall 16, a discharge gas (eg, a mixed gas including neon (Ne) and xenon (Xe)) is filled to generate vacuum ultraviolet rays by gas discharge. A phosphor layer 19 for absorbing vacuum ultraviolet light and emitting visible light is provided. As shown in FIG. 1, the partition wall 16 includes a first partition member 16a formed in a first direction and a second partition member 16b formed in a second direction perpendicular to the first partition member 16a. ), The discharge cells 18 are formed in a matrix structure. In addition, the partition wall may be formed to extend in the first direction, and the plurality of partition walls may be disposed side by side in the second direction to form discharge cells in a stripe structure (not shown).

The phosphor layer 19 formed in each of the discharge cells 18 is formed by applying a phosphor paste on the side surface of the partition wall 16 and the surface of the dielectric layer 14 and firing it. The phosphor layer 19 is formed of phosphors of the same color in the discharge cells 18 formed along the first direction. In addition, the phosphor layer 19 is repeatedly formed by the phosphors of red (R), green (G), and blue (B) in the discharge cells 18 repeatedly arranged along the second direction.

The filter layer 30 according to the embodiment of the present invention includes a first region 30a, a second region 30b, and a third region 30c having different refractive indices according to the color of each phosphor layer 19.

1 and 2, the first region 30a is formed in a portion of each phosphor layer 19 corresponding to the red phosphor layer 19R. The second region 30b is formed in a portion corresponding to the green phosphor layer 19G, and the third region 30c is formed in a portion corresponding to the blue phosphor layer 19B.

The first region 30a, the second region 28b, and the third region 30c extend in a first direction at a position corresponding to each phosphor layer, and extend in a second direction at a position corresponding to each phosphor layer. Are repeatedly arranged accordingly.

In the above configuration, the first region 30a and the second region 30b may be formed of a medium having different refractive indices. For example, the second region 30b is formed of a medium having a smaller refractive index than the first region 30a. The first region 30a and the third region 30c are formed of a medium having the same refractive index.

The index of refraction is represented by the value of the constant n in Snell's law (the law of refraction), which is established between the angle of incidence and the angle of refraction when light refracts at the interface of two isotropic media, and the light refracts when light travels from one material to another The degree to which it breaks. The refractive index is different depending on the type of material. For the same material, the refractive angle is different when the incident angle is different, but the refractive index is constant. When light is incident on the interface between two media having a difference in refractive index, the reflectance becomes larger as the difference between the refractive indices of the two materials and the larger the angle of incidence.

For example, when light enters a medium having a low refractive index into a medium having a high refractive index, the angle of refraction always becomes larger than the angle of incidence. For the above reason, when the incident angles of visible light incident on the first region 30a, the second region 28b and the third region 30c are the same, the refractive angle in the second region 30b having a relatively small refractive index is It is larger than the angle of refraction in the first region 30a and the third region 30c.

In addition, the angle at which green visible light is refracted also becomes larger than the angle at which red visible light and blue visible light are refracted at the interface of the second region 30b forming the filter layer 30. Therefore, the luminance of the green visible light increases in the lateral direction of the front substrate 20, and the phenomenon of reddish display in the lateral direction of the front substrate 20 can be suppressed.

Meanwhile, a sustain electrode 21 and a scan electrode 22 are formed on the bottom surface of the front substrate 20, and the sustain electrode 21 and the scan electrode 22 cross the address electrodes 12 to discharge cells 18. Are covered with a dielectric layer 28 facing each other.

The dielectric layer 28 forms and accumulates wall charges during discharge while protecting the sustain electrode 21 and the scan electrode 22 from gas discharge. The dielectric layer 28 is covered with the protective film 29. The passivation layer 29 is formed of magnesium oxide (MgO) that protects the dielectric layer 28 to increase the secondary electron emission coefficient upon discharge.

The sustain electrode 21 and the scan electrode 22 are provided on the inner surface of the front substrate 20 to form a surface discharge structure corresponding to each discharge cell 18 so as to cause gas discharge in the discharge cell 18. . The sustain electrode 21 and the scan electrode 22 extend in a second direction crossing the address electrode 12.

Each of the sustain electrodes 21 and the scan electrodes 22 includes transparent electrodes 21a and 22a for generating a discharge and bus electrodes 21b and 22b for applying a voltage signal to the transparent electrodes 21a and 22a, respectively. do. Each of the transparent electrodes 21a and 22a is a part which causes surface discharge in the discharge cell 18, and is a transparent material (eg, indium tin oxide, ITO) to secure the aperture ratio of the discharge cell 18. Is formed. The bus electrodes 21b and 22b are formed of a metal material having excellent conductivity to compensate for the high electrical resistance of the transparent electrodes 21a and 22a.

In the driving of the plasma display panel having the above-described configuration, in the reset period, reset discharge is caused by a reset pulse applied to the scan electrode 22. In the addressing period following the reset period, address discharge is caused by a scan pulse applied to the scan electrode 22 and an address pulse applied to the address electrode 12. Thereafter, in the sustain period, sustain discharge is caused by a sustain pulse applied to the sustain electrode 21 and the scan electrode 22.

The sustain electrodes 21 and the scan electrodes 22 serve as electrodes for applying sustain pulses required for sustain discharge, and the scan electrodes 22 serve as electrodes for applying reset pulses and scan pulses. The address electrode 12 serves as an electrode for applying an address pulse. The sustain electrode 21, the scan electrode 22, and the address electrode 12 may have different roles depending on voltage waveforms applied to the sustain electrode 21, the scan electrode 22, and the address electrode 12, respectively.

The plasma display panel selects a discharge cell 18 to be turned on by the address discharge due to the interaction between the address electrode 12 and the scan electrode 22, and the interaction between the sustain electrode 21 and the scan electrode 22. An image is realized by driving the selected discharge cells 18 by the sustain discharge.

FIG. 3 is a cross-sectional view schematically illustrating a relation of visible light refractive index of a dielectric layer, a front substrate, and a filter layer of a plasma display panel according to an exemplary embodiment of the present invention.

Referring to FIG. 3, in the plasma display panel according to the exemplary embodiment of the present invention, the front substrate 20 is colored. However, in the plasma display panel using the colored front substrate 20, the color of the dielectric layer 28 formed on the front substrate 20 to form a complementary color relationship between the front substrate 20 and the back substrate 10 is blue. It is desirable to have color. In this case, in order to display the color of the dielectric layer 28 in blue, the visible light transmittance of the green wavelength band needs to be lowered. In the case of the colored front substrate 20, the ratio of the green visible light scattered toward the lateral direction becomes smaller.

Here, when the plasma display panel in which the front substrate 20 is colored and the plasma display panel in which the front substrate is not colored are compared, when the front substrate 20 is colored, green is compared with blue or red. The scattering transmittance of is low. In addition, the luminance reduction rate of the green visible light increases in the lateral direction of the plasma display panel. Therefore, the luminance ratio of the red visible light increases, so that the reddish magenta color is displayed strongly toward the lateral direction.

In order to solve this phenomenon, it is possible to use a combination of phosphors which can form a very high color temperature, which is disadvantageous in luminance when the color temperature is formed high.

In the present invention, the refractive index n3b of the second region 30b corresponding to the position of the green phosphor layer 19G corresponds to the red phosphor layer 19R in order to eliminate the reddish color displayed in the lateral direction of the front substrate 20. It is formed to be smaller than the refractive indices n3a and n3c of the first region 30a and the third region 30c respectively corresponding to the blue phosphor layer 19B. The refractive index magnitudes of the first region 30a, the second region 28b, and the third region 30c forming the filter layer 30 have a relationship of n3b <n3a = n3c. As described above, each of the regions of the filter layer 30 may have different refractive indices so that the refractive angle θb of the green visible light may be larger than the refractive angles θa and θc of the red visible or blue visible light.

Meanwhile, in the plasma display panel according to the exemplary embodiment of the present invention, the refractive indexes of the filter layer 30, the front substrate 20, and the dielectric layer 28 may be different from each other.

The general glass material mainly used for the front substrate 20 has a refractive index of 1.52 and a standard atmospheric refractive index of 1.00029. In this case, the critical angle of incidence at the interface between the front substrate 20 and the atmosphere is approximately 40 degrees.

The front substrate 20 according to the embodiment of the present invention may use a high density glass material to make the refractive index larger than that of the ordinary glass material. As described above, the front substrate 20 is preferably made of a glass material having a refractive index larger than that of the glass material. By the way, this invention is not necessarily limited to this, The transmittance | permeability of visible light can be improved also with the structure of the glass material which can transmit visible light.

FIG. 4 is a diagram illustrating visible light refractive index relationships of a dielectric layer, a front substrate, and a filter layer of a plasma display panel according to an exemplary embodiment of the present invention.

Referring to FIG. 4, it can be seen that the refractive index n1 of the dielectric layer 28 is formed to be the same as the refractive index n2 of the front substrate 20. In this case, the incidence angle of visible light incident on the front substrate 20 through the dielectric layer 28 and the incidence angle of visible light incident on the filter layer 30 through the front substrate 20 have the same angle to transmit the boundary surfaces thereof. The transmittance of visible light can be kept constant.

On the other hand, when the refractive index n 2 of the front substrate 20 is smaller than the refractive index n 3 of the filter layer 30, the visible light has a higher refractive index from the front substrate 20 having a lower refractive index than the filter layer 30. Since it is transmitted in the (30) direction, it has a refractive angle smaller than the incident angle.

As such, when the refraction angle is smaller than the incident angle in the process of transmitting the visible light to the filter layer 30 through the front substrate 20, the visible light is transmitted closer to the linear light, thereby increasing the transmittance of the visible light.

As described above, the visible light is gradually refracted by the medium having a small refractive index from the medium having a large refractive index, and is displayed to be refracted closer to the linear light.

Even in this state, the present invention increases the luminance of the green visible light in the lateral direction of the colored front substrate 20, thereby suppressing the phenomenon of reddish display in the lateral direction of the front substrate 20. FIG.

As described above, among the regions of the filter layer 30, the first region 30a and the third region (3b) having the refractive index n3b of the second region 30b corresponding to the green phosphor layer 19G corresponding to another phosphor layer ( Smaller than the refractive index (n3a, n3c) of 30c). The refractive index n3a of the first region 30a corresponding to the red phosphor layer 19R and the refractive index n3c of the third region 30c corresponding to the blue phosphor layer 19B may be the same.

When the refractive indices of the respective regions are different from each other, the incidence angle of the visible light incident through the front substrate 20 and the refractive angle of the visible light refracted in each region have different angles. For example, when the refractive index n3b of the second region 30b is smaller than the refractive indices n3a and n3c of the first region 30a and the third region 30c, the refractive index of the second region 30b is refracted in the second region 30b. The refraction angles θb2 of the visible light are larger than the refraction angles θa2 and θc2 of the visible light refracted in the first region 30a and the third region 30c, respectively. In addition, the angles of refraction of the visible light refracted into the atmosphere through the respective regions also have different angles. That is, the incident angle θb3 of the visible light incident into the atmosphere through the second region 30b is greater than the incident angles θa3 and θc3 of the visible light respectively incident into the atmosphere through the first region 30a and the third region 30c. Becomes larger. Therefore, the angles of refraction θb4 of the visible light refracted into the atmosphere through the second region 30b are higher than those of the visible light refracted into the air through the first region 30a and the third region 30c, respectively. Becomes larger. For reference, the incident angles θb1 of the visible light incident on the second area 30b through the front substrate 20 are the incident angles θa1 and θc1 of the visible light respectively incident on the first area 30a and the third area 30c. )

As described above, in the process of transmitting visible light to each region of the filter layer 30 through the front substrate 20, the refractive index n3b of the second region 30b corresponding to the green phosphor layer 19G is different from the phosphor layer. The refractive angles θb4 of visible light refracted into the atmosphere through the second region 30b are smaller than the refractive indices n3a and n3c of the corresponding first region 30a and the third region 30c. It becomes larger than the refraction angles θa4 and θc4 of visible light respectively refracted through the 30a) and the third region 30c into the atmosphere. Therefore, by increasing the luminance of the green visible light in the lateral direction of the colored front substrate 20, it is possible to suppress the phenomenon of reddish display in the lateral direction of the front substrate 20.

On the other hand, the detailed description of the present invention has been described with reference to specific embodiments, of course, various modifications are possible without departing from the scope of the invention.

For example, the refractive index n1 of the dielectric layer 28 may be formed of a medium smaller than the refractive index n2 of the front substrate 20. In this case, the visible light is transmitted from the dielectric layer 28 having a lower refractive index to the front substrate 20 having a higher refractive index than that of the front substrate 20 so that the visible light has a refractive angle smaller than the incident angle.

As such, when the visible light is transmitted through the dielectric layer 28 to the front substrate 20 and the refractive angle becomes smaller than the incident angle, the visible light is transmitted closer to the linear light, thereby increasing the transmittance of the visible light.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below but also by the equivalents of the claims.

As described above, the plasma display panel according to the present invention has an effect of preventing the display efficiency from being reduced due to reflection of external light due to the enhancement of the bright room contrast due to the complementary color effect between the elements constituting the plasma display panel.

In addition, by maintaining the complementary color relationship to the components of the plasma display panel to form an external light reflection layer to reduce the external light reflection, there is an effect that can reduce the external light reflection brightness and minimize the brightness reduction.

In addition, the visible light refractive index of the filter layer is adjusted differently according to the color of the phosphor layer to improve the visible light transmittance, thereby reducing the phenomenon of appearing reddish in the lateral direction of the colored front substrate.

Claims (7)

A first substrate; A second substrate spaced apart from the first substrate and colored; Barrier ribs disposed between the first substrate and the second substrate to partition respective discharge cells; An address electrode extending from the first substrate in a first direction corresponding to the discharge cell; A display electrode extending from the second substrate in a second direction crossing the first direction corresponding to the discharge cell; Red, green, and blue phosphor layers formed in the discharge cells in the same color along the first direction and repeated in different colors along the second direction; And A filter layer formed on an outer surface of the second substrate, The filter layer has at least two refractive indexes depending on the color of the phosphor layer. The method of claim 1, The filter layer is A first region corresponding to the red phosphor layer; A second region corresponding to the green phosphor layer; And And a third region corresponding to the blue phosphor layer. The method of claim 2, And the first region, the second region, and the third region extend along the first direction. The method according to claim 2 or 3, And the first region and the second region have different refractive indices. The method of claim 4, wherein And the second region has a refractive index smaller than that of the first region. The method of claim 5, And the first region and the third region have the same refractive index. The method of claim 1, The filter layer has a larger refractive index than the front substrate.

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