KR20050013359A - Plasma display panel - Google Patents

Abstract

PURPOSE: A plasma display panel is provided to achieve improved screen quality and contrast ratio by forming an upper anti-reflection film on a front filter and a panel anti-reflection film on an upper substrate of the panel. CONSTITUTION: A plasma display panel comprises a display panel(130) formed by coupling an upper substrate and a lower substrate; a front filter(144) arranged on a front surface of the display panel so as to prevent a reflection of an external light(148); a panel anti-reflection film(146) formed on the upper substrate of the display panel such that the panel anti-reflection film prevents the external light from being re-reflected toward the front filter; and an upper anti-reflection film(142) formed on a front surface of the front filter such that the upper anti-reflection film prevents the external light from being re-reflected to outside.

Description

Plasma Display Panel {PLASMA DISPLAY PANEL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a plasma display panel capable of improving image quality and contrast ratio.

Plasma Display Panels (hereinafter referred to as "PDPs") are characterized by emitting phosphors by 147 nm ultraviolet rays generated during discharge of an inert mixed gas such as He + Xe, Ne + Xe or He + Ne + Xe. An image containing graphics is displayed. Such PDPs are not only thin and large in size, but also greatly improved in image quality due to recent technology development. In particular, the three-electrode AC surface discharge type PDP has advantages of low voltage driving and long life because wall charges are accumulated on the surface during discharge and protect the electrodes from sputtering caused by the discharge.

1 is a perspective view illustrating a discharge cell structure of a conventional plasma display panel.

Referring to FIG. 1, a discharge cell of a three-electrode AC surface discharge type PDP includes a scan electrode Y and a sustain electrode Z formed on the upper substrate 10, and an address electrode formed on the lower substrate 18. X). Each of the scan electrode Y and the sustain electrode Z has a line width smaller than that of the transparent electrodes 12Y and 12Z and the transparent electrodes 12Y and 12Z, and the metal bus electrodes 13Y, which are formed at one edge of the transparent electrode, respectively. 13Z).

The transparent electrodes 12Y and 12Y are typically formed on the upper substrate 10 by indium-tin-oxide (ITO). The metal bus electrodes 13Y and 13Z are usually formed of metals such as chromium (Cr) and formed on the transparent electrodes 12Y and 12Z to reduce the voltage drop caused by the transparent electrodes 12Y and 12Z having high resistance. The upper dielectric layer 14 and the passivation layer 16 are stacked on the upper substrate 10 having the scan electrode Y and the sustain electrode Z side by side. In the upper dielectric layer 14, wall charges generated during plasma discharge are accumulated. The protective layer 16 prevents damage to the upper dielectric layer 14 due to sputtering generated during plasma discharge and increases emission efficiency of secondary electrons. As the protective film 16, magnesium oxide (MgO) is usually used.

The lower dielectric layer 22 and the partition wall 24 are formed on the lower substrate 18 on which the address electrode X is formed, and the phosphor layer 26 is coated on the surfaces of the lower dielectric layer 22 and the partition wall 24. The address electrode X is formed in the direction crossing the scan electrode Y and the sustain electrode Z. The partition wall 24 is formed in a stripe or lattice shape to prevent the ultraviolet rays and the visible light generated by the discharge from leaking to the adjacent discharge cells. The phosphor layer 26 is excited by ultraviolet rays generated during plasma discharge to generate visible light of any one of red, green, and blue. Inert mixed gas is injected into the discharge space provided between the upper and lower substrates 10 and 18 and the partition wall 24.

The PDP is time-divisionally driven by dividing one frame into several subfields having different number of emission times in order to implement grayscale of an image. Each subfield is divided into an initialization period for initializing the full screen, an address period for selecting a scan line and selecting a cell in the selected scan line, and a sustain period for implementing gradation according to the number of discharges.

For example, when the image is to be displayed in 256 gray levels, as shown in FIG. 2, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields SF1 to SF8. As described above, each of the eight subfields SF1 to SF8 is divided into an initialization period, an address period, and a sustain period. The initialization period and the address period of each subfield are the same for each subfield, while the sustain period is increased at a rate of 2n (n = 0, 1, 2, 3, 4, 5, 6, 7) in each subfield.

In the PDP driven as described above, a front filter is installed on the upper substrate 10 to shield electromagnetic waves and prevent reflection of external light.

3 is a cross-sectional view schematically illustrating one side of a conventional plasma display panel.

Referring to FIG. 3, a conventional PDP includes a panel 30 formed by joining an upper substrate and a lower substrate, a front filter 44 installed on the front of the panel 30, a front surface of the front filter 44, and a front panel 44. It is attached to each of the rear surfaces and has upper and lower antireflection films 42 and 46 to prevent the external light 48 from being reflected back to the outside again.

The front filter 44 shields electromagnetic interference (EMI) and prevents reflection of the external light 48. One side edge of the front filter 44 supports a filter support 70 for electrically connecting the front filter 44 to a back cover of a PDP (not shown), and the front filter 44 and the filter support 70. A support member 72 is provided for the purpose.

The filter support 70 grounds the front filter 44 to the bag cover and prevents electromagnetic interference (EMI) from being emitted to the side.

The upper antireflective film 42 is formed on the surface of the front filter 44 to prevent the light incident from the outside from being reflected back to the outside, thereby improving the contrast of the PDP. At this time, the upper antireflective film 42 has a directionality to prevent the incident light is reflected back to the front surface and has a reflectance of about 2% to 3%.

The lower antireflective film 46 is formed on the rear surface of the front filter 44 to prevent the external light 48 passing through the upper antireflective film 42 and the front filter 44 from being reflected back to the outside to reduce the contrast of the PDP. Will be improved. In this case, the lower antireflective film 46 has a direction to prevent the incident light from being reflected back toward the panel 30 and has a reflectance of about 2% to 3%.

The conventional PDP can improve the contrast ratio by preventing the external light 48 incident from the outside from being reflected back to the outside by using the upper and lower anti-reflective films 42 and 46. However, in the conventional PDP, the external light 48 passing through the front filter 44 is transmitted to the panel 30 so that the light reflected from the panel 30 is internally interposed between the lower antireflective film 46 and the panel 30. This will cause reflections, which will degrade the quality and contrast ratio.

This will be described with reference to FIG. 4. Here, the external light 48 will be described assuming 100 as shown in FIG.

First, when the external light 48 is incident on the upper antireflective film 42, the upper antireflective film 42 reflects about 2 to 3% of the external light 48 and transmits the rest. Accordingly, in the upper anti-reflective film 42, light of about 2 is reflected back to the outside, and light of about 98 is transmitted to the front filter 44.

The light incident on the front filter 44 is transmitted through the lower anti-reflective film 46 by the 50% transmittance of the front filter 44 to enter the panel 30.

Light incident on the panel 30 is reflected toward the lower anti-reflective film 46 by about 30% reflectance of the panel 30. 14.7 light reflected by the panel 30 to the lower anti-reflective film 46 is reflected back to the panel 30 by the lower anti-reflective film 46, and the rest is transmitted through the front filter 44. do. About 0.3 light reflected by the lower antireflective film 46 causes scattering or internal reflection between the panel 30 and the lower antireflective film 46.

On the other hand, the light transmitted through the front filter 44 is 7.2 out of the front filter 44 through the upper anti-reflective film 42 is emitted to the outside. Accordingly, the 9.2 external light 48 of the 100 external light 48 is reflected back to the outside. Therefore, in the conventional PDP, as described above, part of the external light 48 is reflected back to the outside again, or scattering or internal reflection occurs between the lower anti-reflective film 46 and the panel 30, thereby reducing gray and contrast ratios. .

In addition, in the conventional PDP, the ground area of the filter support part 70 electrically grounded to the front filter 44 is small due to the lower antireflection film 46, and the resistance of the ground plane is high.

Accordingly, an object of the present invention is to provide a plasma display panel capable of improving image quality and contrast ratio.

1 is a perspective view showing a discharge cell structure of a conventional three-electrode AC surface discharge type plasma display panel.

2 is a diagram illustrating a frame for expressing 256 gray levels in a typical plasma display panel.

3 is a cross-sectional view schematically showing one side of a conventional plasma display panel.

4 is a cross-sectional view showing the transmission and re-reflection rate of the external light in the conventional plasma display panel.

5 is a cross-sectional view schematically showing one side of a plasma display panel according to an embodiment of the present invention.

6 is a cross-sectional view schematically showing the front filter shown in FIG.

FIG. 7 is a cross-sectional view illustrating transmission and re-reflectance of external light in the plasma display panel according to an exemplary embodiment of the present invention. FIG.

<Description of Symbols for Main Parts of Drawings>

10: upper substrate 12Y, 12Z: transparent electrode

13Y, 13Z: bus electrodes 14, 22: dielectric layer

16: protective film 18: lower substrate

24: partition 26: phosphor layer

30, 130: panel 42, 142: upper antireflective film

44, 144: front filter 46: lower antireflective film

48, 148: external light 70, 170: filter support

72, 172: support member 146: panel antireflective film

150: optical film 152: glass

154: EMI shielding film 156: NIR shielding film

In order to achieve the above object, a plasma display panel according to an exemplary embodiment of the present invention includes a display panel in which an upper substrate and a lower substrate are bonded, a front filter disposed on a front surface of the display panel to prevent reflection of external light, and the display. And a panel anti-reflective film formed on the upper substrate of the panel to block light reflected from the external light back toward the front filter.

The plasma display panel may further include an upper anti-reflective film formed on the front surface of the front filter to block the external light from being reflected back to the outside.

In the plasma display panel, the panel anti-reflection film is formed by a laminating process.

In the plasma display panel, the panel anti-reflective film and the upper anti-reflective film may be directional to block the external light from being reflected back to the front surface.

The plasma display panel may further include a support member connected to a rear surface of the front filter to ground and support the front filter.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 5 to 7.

Referring to FIG. 5, a plasma display panel (hereinafter referred to as a “PDP”) according to an exemplary embodiment of the present invention may include a panel 130 formed by bonding an upper substrate and a lower substrate together with the panel 130. A front filter 144 installed on the front surface, an upper antireflection film 142 attached to the front surface of the front filter 144 to prevent the external light 148 from being reflected back to the outside, and the panel A panel antireflection film 146 is formed directly on the 130 to prevent the light incident through the front filter 144 from being reflected back to the outside.

The panel 130 includes an upper plate having a sustain electrode pair, an upper dielectric layer (not shown), and a passivation layer (not shown) sequentially formed on an upper substrate (not shown), and an illustration sequentially formed on the lower substrate. And a lower plate having an address electrode, a lower dielectric layer, a partition, and a phosphor layer (not shown). Here, the upper substrate and the lower substrate are spaced in parallel by the partition wall. The panel antireflection film 146 is formed on the upper substrate of the panel 130.

The panel antireflective film 146 is formed on the upper substrate by a laminating process. The panel antireflective film 146 prevents light from being scattered or internally reflected between the front filter 144 and the panel 130 to improve the contrast of the PDP. At this time, the panel antireflective film 146 has a direction to prevent the incident light is reflected back toward the front filter 144 and has a reflectance of about 2% to 3%.

The front filter 144 shields electromagnetic interference (EMI) and prevents reflection of the external light 148. To this end, the front filter 144 may include the optical film 150, the glass 152, the EMI shield 154 and the near infrared (NIR) shield 156 as shown in FIG. 6. It is provided. Here, in practice, an adhesive layer is formed between the films 150, 152, 154 and 156 of the front filter 144 to bond the films 150, 152, 154 and 156.

The optical characteristic film 150 reduces the transmittance of red (R) and green (G) among the light incident from the panel 130, and improves the optical characteristic of the PDP by increasing the transmittance of blue (B).

The glass 152 prevents the front filter 144 from being damaged from an external impact. In other words, the glass 152 supports the front filter 144 to prevent the front filter 144 from being damaged from an external impact. The EMI shield 154 shields the EMI to prevent the EMI incident from the panel 130 from being emitted to the outside. The NIR shielding film 156 shields the NIR incident from the panel 130. The NIR shielding film 156 prevents the NIR above the reference from being emitted to the outside so that the signals transmitted from the remote controller or the like to the panel 130 can be normally transmitted. Meanwhile, the NIR shielding film 156 may be formed of one layer together with the optical characteristic film 150.

One side edge of the front filter 144 supports a filter support unit 170 for electrically connecting the front filter 144 to a back cover of a PDP (not shown), and the front filter 144 and the filter support unit 170. The support member 172 is installed.

The filter support 170 grounds the front filter 144 to the bag cover and prevents electromagnetic interference (EMI) from being emitted to the side.

The upper antireflective film 142 is formed on the surface of the front filter 144 to prevent the light incident from the outside from being reflected back to the outside to improve the contrast of the PDP. At this time, the upper antireflection film 42 has the same directionality as the panel antireflection film 146 and has a reflectance of about 2% to 3% to prevent the incident light from being reflected back to the front surface again.

As described above, the PDP according to the embodiment of the present invention prevents the external light 148 incident from the outside from being reflected back to the outside by using the upper anti-reflective film 142, and the second non-reflective film 146. By using the front filter 144 to prevent the light incident on the panel 130 from being reflected back toward the front filter 144, the contrast ratio may be improved.

This will be described with reference to FIG. 4. Here, the external light 148 is assumed to be 100 as shown in FIG. 7.

First, when the external light 148 is incident on the upper anti-reflective film 142, the upper anti-reflective film 142 reflects the external light 148 of about 2 to 3% and transmits the rest. Accordingly, in the upper anti-reflective film 142, light of about 2 is reflected back to the outside, and light of about 98 is transmitted to the front filter 144.

The light incident on the front filter 144 is incident on the panel 130 by passing about 49 light through the front filter 144 by about 50% transmittance of the front filter 144.

Light incident toward the panel 130 is prevented from being reflected back toward the front filter 144 by the panel antireflective film 146 formed on the upper substrate of the panel 130. Accordingly, about 49 incident light incident toward the panel 130 is reflected toward the front filter 144 by the reflectance of the panel antireflective film 146. About 0.98 light reflected by the panel antireflective film 146 is emitted through the upper antireflective film 142 by 0.49 by the transmittance of the front filter 144. Accordingly, the 2.49 external light 148 of the 100 external light 148 is reflected back to the outside. Therefore, the PDP according to the embodiment of the present invention can improve the image quality and the contrast ratio since the ratio of the part of the external light 148 to be reflected back to the outside again than before.

In addition, the PDP according to the embodiment of the present invention increases the ground area of the filter support unit 170 electrically grounded to the front filter 144 since the panel antireflection film is not attached to the rear surface of the front filter 144. Can reduce the resistance of the ground plane.

As described above, the plasma display panel according to the embodiment of the present invention includes an upper antireflection film attached to the surface of the front filter and a panel antireflection film formed on the upper substrate of the panel. Accordingly, the present invention can improve the image quality and the contrast ratio by reducing the re-reflection of light incident from the outside back to the outside. In addition, the present invention can improve the image quality and the contrast ratio by preventing the scattering of light generated between the panel and the front filter by the panel antireflection film formed on the panel.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (5)

A display panel in which the upper substrate and the lower substrate are bonded together; A front filter disposed on the front surface of the display panel to prevent reflection of external light; And a panel anti-reflective film formed on the upper substrate of the display panel to block the light from which the external light is reflected back to the front filter. The method of claim 1, And an upper anti-reflective film formed on the front surface of the front filter to block the external light from being reflected back to the outside. The method of claim 1, The panel anti-reflective film is formed by a laminating process. The method of claim 2, And the panel anti-reflective film and the upper anti-reflective film have a direction for blocking the external light from being reflected back to the front surface. The method of claim 1, And a support member connected to a rear surface of the front filter to ground and support the front filter.