JP2008177126A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display panel having a simple structure and high contrast even in a bright environment, and capable of displaying a high-quality image. <P>SOLUTION: This plasma display panel is provided with: a front substrate 21 and a back substrate 11 arranged separately from each other; barrier ribs 14 partitioning discharge spaces formed between the front substrate and the back substrate; and a phosphor layer 15 emitting light by generating discharge in discharge cells partitioned by the barrier ribs and being excited by ultraviolet rays generated by the discharge. The plasma display panel is also provided with louvers 26 formed between the front substrate and the barrier ribs and at positions corresponding to boundaries of the respective discharge cells. The louver 26 has an upper surface 27 and a lower surface 28 orthogonal to or tilting with respect to the front substrate, and facing each other, wherein visible light reflectivity of the upper surface 27 for entering external light from an oblique upper side toward the discharge cell is different from that of the lower surface 28. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma display panel.

  In recent years, expectations for flat displays replacing CRT displays have increased, and liquid crystal displays and plasma display panels with reduced depth have become widespread. In particular, plasma display panels are often used for large-screen thin displays.

  A plasma display panel is a display device that generates visible light by exciting phosphors with ultraviolet rays generated by gas discharge, and forms an image by controlling light emission for each discharge cell that partitions a discharge space.

  For example, in a matrix display type plasma display panel, a large number of electrodes (display electrodes and address electrodes) are arranged in a lattice pattern, and an image is formed by selectively emitting light from discharge cells that intersect each electrode.

  The light emission principle of each discharge cell is as follows. That is, when a pulsed AC voltage of several tens to several hundreds kHz is applied between the opposing electrodes of the discharge cell to be lit, wall charges are accumulated and display discharge occurs, and the components of the discharge gas enclosed in the discharge cell Ultraviolet rays are emitted from Xe. The emitted ultraviolet light excites red, blue, and green phosphors formed in the discharge cell to generate visible light of each color. Here, one set of discharge cells of three colors is used as one pixel, and the full color display of 16.7 million colors is possible by controlling the emission intensity of each color in, for example, 256 levels.

  As described above, the light emission of the plasma display panel uses the discharge phenomenon, so the response speed is fast, and since the phosphor is used similarly to the CRT, the color reproducibility is good, so it is suitable for displaying moving images such as TV images. ing. In addition, because of its structure, the plasma display panel can realize a large screen relatively easily, is self-luminous, has no viewing angle dependency, and has an excellent image display capability with high contrast in a dark room. As a large-screen TV receiver, demand is rapidly expanding.

  However, since a high-reflectance phosphor is formed in each discharge cell of the plasma display panel, high contrast can be realized in a dark environment, but reflection of outside light is large in a bright environment and the contrast is lowered. There is a problem that it is easy. Therefore, there is a demand for a plasma display panel that can maintain high contrast even in a bright environment.

  In response to such a demand, for example, a stripe-shaped light absorption layer is arranged on the front panel so as to overlap with the partition walls defining the discharge space, and light is put inside the optical filter arranged on the observer side of the front panel. A technique for providing an absorption layer is known. Thereby, the light that reaches the plasma display panel and is reflected internally can be attenuated.

For example, a technique has been proposed in which a resin sheet having a louver structure in which transparent areas and dark color areas adjacent to the transparent areas are alternately formed is disposed on the front surface of the plasma display panel (Patent Document 1). Since the resin sheet of Patent Document 1 can shield external light from obliquely above the plasma display panel, such as light incident from a ceiling lighting fixture, the luminance of the plasma display panel is reduced. In contrast, it is possible to display an image with high contrast even in a bright room environment.
JP 2004-295045 A

  However, the conventional plasma display panel in which the light absorption layer is provided inside the front panel and the optical filter has a problem that the panel luminance is lowered because the image light to be observed is also absorbed by the light absorption layer.

  In addition, the plasma display panel using the resin sheet of Patent Document 1 has a problem in that moiré may occur in the formed image due to the difference between the pixel pitch and the pitch of the louver structure, and the resolution deteriorates. It was. Moreover, the plasma display panel using the resin sheet provided with such a louver structure has a problem that the cost is high.

  Accordingly, an object of the present invention is to provide a plasma display panel capable of displaying a high-quality image with a simple configuration and high contrast even in a bright environment.

The object of the present invention is achieved by a plasma display panel having the following configuration. A discharge is generated in a discharge cell defined by the barrier ribs, a front plate and a rear plate arranged apart from each other, a barrier partitioning a discharge space formed between the front plate and the rear plate, and a discharge cell. A plasma display panel including a phosphor layer that emits light by being excited by generated ultraviolet rays,
A louver formed between the front plate and the barrier ribs at a position corresponding to the boundary of each discharge cell;
The louver has an upper surface and a lower surface facing each other perpendicular to or inclined with respect to the front plate. The louver has a visible light reflectance on the upper surface on which external light is incident on the discharge cell obliquely from above and a visible surface on the lower surface. The light reflectance is different.

  Thus, according to the present invention, it is possible to provide a plasma display panel having a simple configuration and high contrast even under a bright environment and capable of displaying a high-quality image.

(Embodiment)
A plasma display panel according to the present embodiment will be described with reference to the drawings. In a bright environment where indoor lighting or sunlight is incident, external light from all directions is incident on the plasma display panel. Among them, external light incident from an oblique direction has a great influence on a decrease in contrast. Therefore, the plasma display panel according to the present embodiment includes a light absorption layer that absorbs visible light between the front substrate and the barrier ribs at each boundary of the discharge cells, and external light incident obliquely from above is phosphor. It is characterized in that it is prevented from entering the layer and the contrast is improved.

  The light absorption layer of the present embodiment is a member that selectively absorbs and reflects incident light, and corresponds to a “louver” in the claims. Hereinafter, the configuration of the plasma display panel of the present embodiment will be described.

  FIG. 1 is a schematic cross-sectional view showing the configuration of the plasma display panel 1 of the present embodiment. The plasma display panel 1 includes a front panel 20 and a back panel 10 that are spaced apart from each other. A discharge gas such as Xe, He, or Ne is sealed in a discharge space that is a gap between the front panel 20 and the back panel 10.

  The back panel 10 includes a phosphor layer 15, a partition wall 14, a dielectric layer 13, an address electrode 12, and a back substrate 11 in order from the viewer side. More specifically, for example, an address electrode 12 and a dielectric layer 13 are formed so as to cover the address electrode 12 on the surface on the observer side of the rear substrate 11 made of a glass substrate, and further protrude toward the observer side of the dielectric layer 13. Thus, the partition wall 14 is formed. The phosphor is applied to the surfaces of the barrier ribs 14 and the dielectric layer 13, leaving only the top of the barrier ribs 14, thereby forming the phosphor layer 15.

  The front panel 20 includes a front substrate 21 made of, for example, a glass substrate, a counter electrode, a dielectric layer 24, a light absorption layer 26, and a protective layer 25. More specifically, a counter electrode having a two-layer structure of a transparent electrode 22 having a high transmittance and a bus electrode 23 having a low resistance value, and a light absorption layer 26 are formed on the surface of the front substrate 21 on the back panel side. The dielectric layer 24 covers the transparent electrode 22, the bus electrode 23, and the light absorption layer 26. Further, a protective layer 25 is formed on the surface of the dielectric layer 24 on the back panel side.

  The counter electrode has a short electrode width in the vertical direction (Z-axis direction) in FIG. 1, and a current corresponding to one discharge cell is energized. Further, since the conduction path is configured to be long in the depth direction (Y-axis direction) in FIG. 1 and the currents of the discharge cells are added together, it is necessary to reduce the resistance value. Therefore, the counter electrode is not transparent but has a low resistance, for example, chromium, copper, silver, etc., on the transparent electrode 22 using a thin transparent material such as a tin oxide / indium (ITO) film or a tin oxide film. A two-layer structure is provided in which a bus electrode 23 using a metal material is provided.

  The light absorption layer 26 has first and second boundary surfaces which are boundary surfaces with the dielectric layer 24, and the first and second boundary surfaces have different visible light reflectivities. That is, the first boundary surface absorbs light in the visible light wavelength band (400 to 700 nm), and the second boundary surface reflects visible light. For example, the light absorbing layer 26 may be formed of a visible light absorbing material made of black Ag or the like, and a visible light reflecting film may be formed on the second boundary surface. The light absorption layer 26 is disposed perpendicular to the surface of the front substrate 21 at each discharge cell boundary, and is formed on the front substrate 21 so as to extend parallel to the top of the barrier rib 14.

  When the plasma display panel shown in FIG. 1 is applied to a TV receiver or the like, the upper side surface that is located above the horizontal direction is defined as the first boundary surface, and the lower side surface that is located below the first boundary surface. Is the second boundary surface.

  A discharge gas such as Xe, He, or Ne is sealed in the discharge space formed between the back panel 10 and the front panel 20. In the plasma display panel configured as described above, when a pulsed AC voltage is applied to the counter electrode of the discharge cell, display discharge occurs and ultraviolet rays are generated. The generated ultraviolet light excites the phosphor of the phosphor layer 15 formed on the back panel to generate visible light, which is emitted to the viewer as image light.

  Here, since the light absorption layer 26 is formed closer to the observer than the discharge cells, a part of the image light emitted from each discharge cell is incident on the first boundary surface 27 of the light absorption layer 26 and absorbed. However, since a visible light reflecting film is formed on the second boundary surface 28, most of the image light is emitted to the viewer side. Thus, since visible light is reflected on one side surface of the light absorption layer 26, a decrease in luminance due to the provision of the first boundary surface can be suppressed.

  In addition, a decrease in contrast due to reflection of external light incident on the plasma display panel in an oblique direction is suppressed as follows. That is, as indicated by the arrows in the figure, external light incident from an oblique direction passes through the front substrate 21 and most of the light enters the first boundary surface 27 of the light absorption layer 26. As a result, most of the external light incident from obliquely above is absorbed by the first boundary surface, so that it does not become diffused light. Therefore, external light is not reflected by the phosphor layer 15, and a decrease in contrast can be suppressed.

  As described above, the plasma display panel according to the present embodiment includes a light absorption layer that absorbs light in the visible wavelength band on one of the boundary surfaces, so that the contrast is reduced due to reflection of external light such as illumination and sunlight. Can be suppressed.

  Further, in the plasma display panel of the present embodiment, a layer having a boundary surface that reflects light in the visible light wavelength band is provided between the back plate and the partition wall, so that the video light emitted from the discharge cell is The light can be reflected and guided to the viewer side, and a decrease in the brightness of the plasma display panel can be suppressed.

  In particular, since the plasma display panel of the present embodiment includes the light absorption layer having the first boundary surface that absorbs visible light, the effect of improving the contrast is high in an environment where external light is incident obliquely from above.

  In addition, the plasma display panel of the present embodiment can be realized with a simple configuration and low cost because a light absorption layer may be formed for each boundary between discharge cells.

  In the present embodiment, an AC plasma display panel that applies a pulsed AC voltage to the counter electrode has been described. However, the present invention is not limited to this. The present invention can be applied to a plasma display panel using a phosphor without being limited to a direct current type, a surface emitting type, a counter discharge type, and the like.

  In the present embodiment, the light absorption layer has a visible light reflection film formed on one surface of the light absorption material, but the present invention is not limited to this. For example, the visible light absorbing layer may be formed on one surface of the visible light reflecting material, or the light absorbing layer may be configured by combining the visible light absorbing material and the visible light reflecting material.

  In the present embodiment, the first boundary surface and the second boundary surface of the light absorption layer are arranged in parallel to each other and orthogonal to the surface of the front substrate, but the present invention is not limited to this. Any structure can be used as long as it can block external light incident on the plasma display panel in an oblique direction and can reflect the emitted image light. For example, the boundary surface is inclined with respect to the surface of the front substrate. A light absorption layer may be disposed.

  In this embodiment, the light absorption layer is formed on the front substrate. However, the present invention is not limited to this, and it may be formed between the front substrate and the partition. Moreover, the structure of the front panel and back panel demonstrated by the said embodiment is an example, and is not restricted to these.

  The present invention is suitable for TV receivers, information terminal displays, and the like that require display of bright images with high contrast.

Schematic sectional view showing the structure of the plasma display panel in the embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma display panel 10 Back panel 11 Back substrate 12 Address electrode 13 Dielectric layer 14 Partition 15 Phosphor layer 20 Front panel 21 Front substrate 22 Transparent electrode 23 Bus electrode 24 Dielectric layer 25 Protective layer 26 Light absorption layer 27 1st boundary Surface 28 Second boundary surface

Claims (5)

A front plate and a back plate that are spaced apart from each other, a partition that partitions a discharge space formed between the front plate and the back plate, and a discharge generated in a discharge cell partitioned by the partition. A plasma display panel comprising a phosphor layer that emits light by being excited by ultraviolet rays generated by the discharge,
A louver formed between the front plate and the barrier ribs at a position corresponding to a boundary between the discharge cells;
The louver has an upper side surface and a lower side surface facing each other perpendicular to or inclined with respect to the front plate, and visible light reflectance of the upper side surface on which external light from obliquely upward to the discharge cell is incident, The plasma display panel, wherein the visible light reflectance of the lower surface is different.   2. The plasma display panel according to claim 1, wherein an upper side surface of the louver has the visible light reflectance at which a component that absorbs visible light is higher than a component that reflects.   2. The plasma display panel according to claim 1, wherein a lower side surface of the louver has a value of the visible light reflectance at which a component that absorbs visible light is lower than a component that reflects.   The plasma display panel according to claim 1, wherein the louvers are formed on the front plate in a direction parallel to the partition walls.   2. The plasma display panel according to claim 1, wherein an upper side surface of the louver on which external light from an oblique upper side enters the discharge cell has a lower visible light reflectance than the lower side surface.

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