JP4386214B2 - Plasma display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma display panel used for a display terminal or display device of a computer or a television display, and more particularly to a plasma display panel with improved contrast.
[0002]
A plasma display panel known as a display panel using gas discharge is generally used as a display means for OA equipment because of its excellent display brightness and contrast, and in recent years it can be displayed on television by colorization. It is attracting attention as a thin full-color flat panel display that can be easily enlarged. Therefore, there is a demand for the flat panel to realize a large screen, a high-definition, high-contrast, clear, high-display quality screen.
[0003]
[Prior art]
As a basic structure of a conventional color display surface discharge type plasma display panel (PDP), for example, an AC drive type gas discharge display panel, as shown in FIG. A unit electrode emission region EU in matrix display has a three-electrode structure in which a pair of X and Y discharge electrodes (display electrodes) 12 and address electrodes A are opposed to each other.
[0004]
The discharge electrode pair 12 composed of X and Y for surface discharge forming the display line is provided on the glass substrate 11 on the display surface H side with respect to the discharge space 24, and minimizes shielding of display light. Therefore, on the transparent electrode 12a made of a transparent conductive film such as a nesa film or ITO (Indium Tin Oxide) film, the conductivity of the transparent electrode 12a is made narrower than the transparent electrode 12a (low resistance) Therefore, the metal bus electrode 12b made of a metal film is laminated.
[0005]
The discharge electrode pair 12 is covered in an insulating state with respect to the discharge space 24 by an insulating layer (dielectric layer) 13 for AC driving that uses a wall charge to maintain gas discharge. A protective film 14 made of an MgO film having a thickness of about several thousand mm is further provided on the surface of 13.
[0006]
On the other hand, the address electrodes A for selectively emitting light in the unit light emitting areas EU are arranged on the glass substrate 21 on the back side at a constant pitch so as to be orthogonal to the discharge electrode pairs 12 made of X and Y. A stripe-shaped partition wall 22 having a predetermined height is provided between the address electrodes A, whereby the discharge space 24 is partitioned for each unit light emitting region EU in the line direction (length direction of the discharge electrode pair 12), and The interval dimension of the discharge space 24 is defined.
[0007]
Further, the glass substrate 21 is coated with R (red), G (green), and B (blue) so as to cover the upper surface of the address electrode A and the inner surface on the back surface side including the side surface of the stripe-shaped partition wall 22. Three primary color phosphors 23 are provided. In the PDP 1 having such a configuration, the phosphors 23 of the respective colors are excited by ultraviolet rays emitted from the gas discharge in the discharge space 24 during the surface discharge, and full color display by a combination of R, G, and B is possible. In the display, the partition 22 prevents the crosstalk between the unit light emitting regions EU.
[0008]
In the PDP 1 having the above configuration, after providing predetermined components individually for the glass substrates 11 and 21 as described above, the glass substrates 11 and 21 are arranged to face each other so that the periphery of the gap is airtight. It is manufactured by a series of steps of sealing and exhausting the inside to a vacuum, and enclosing a discharge gas composed of neon (Ne) gas containing several percent of xenon (Xe) that generates ultraviolet rays.
[0009]
[Problems to be solved by the invention]
By the way, in order to improve the contrast of the display screen of the PDP 1 having such a configuration, a separate ND (neutral density) filter is currently attached to the front surface of the panel. For example, when an ND filter having a transmittance of 60% is used, the panel emits 60% of light. At this time, the light reflected by the panel in the room passes through this ND filter twice, so that it is reduced to 36%. Therefore, high contrast is obtained even in a bright room. However, when such an ND filter is used, the cost of the panel increases by the cost.
[0010]
In addition, by installing a color filter with high transmittance of the emission color for each pixel of the panel (low transmittance of other emission colors), high contrast can be achieved in a bright room without greatly reducing the brightness of the panel. Obtainable. However, in this case, it is necessary to completely align the three color filters for each pixel. In addition, when the panel glass is distorted in a high-temperature process or the like, it is difficult to align the filter and the yield is lowered, and there is a problem in that these filter material costs and process costs are increased.
[0011]
In view of the above-described conventional problems, the present invention reduces the process cost by a simple configuration using a protective film provided on an insulating layer covering the display electrode in order to insulate and protect the display electrode on the substrate from gas discharge. It is an object of the present invention to provide a plasma display panel that can obtain high contrast in a bright room without being increased.
[0012]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides an insulating layer on an insulating layer covering an electrode disposed on at least one front surface of a pair of substrates opposed to each other via a discharge space. A plasma display panel including a protective film for protecting the layer from discharge, wherein the protective film has a visible light transmittance of 85% or less at least in a portion through which visible light generated based on discharge is transmitted; To do.
[0013]
In the present invention, if the protective film can be controlled to a desired transmittance by some method, it is possible to obtain substantially the same effect as when the ND filter is installed without installing a separate ND filter on the front surface of the panel. It is a thing.
[0014]
For example, it consists of a protective film whose surface is roughened to reflect or scatter visible light, or a magnesium oxide (MgO) film to which an inorganic pigment (W, Co, Mn, etc.) that absorbs visible light is added. By using a colored protective film, the transmittance of the protective film is reduced to 85% or less, preferably 70% or less, without greatly changing the manufacturing process and without increasing the yield or process cost. It is possible to improve the bright room contrast of the screen.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
FIG. 1 is a main part for explaining a first embodiment and a second embodiment of a protective film covering an upper portion of an insulating layer protecting a display electrode provided on a display surface side glass substrate constituting a plasma display panel of the present invention. It is a cross-sectional perspective view.
[0017]
As the first embodiment, as shown in FIG. 1, a protective film 31 covering the upper part of the insulating layer 13 for protecting the display electrode 12 provided on the glass substrate 11 on the panel display surface side is used. (MgO) For example, abrasive particles made of glass beads having a particle diameter of about 20 μm are sprayed on the surface of the film at a flow rate of 120 g / min for several minutes from a position spaced about 10 cm apart by visible light. A structure using a magnesium oxide (MgO) film that is roughened so that the transmittance of (wavelength: 550 nm) is 85% and reflects or scatters visible light is used.
[0018]
As in the second embodiment, as shown in FIG. 1, the upper portion of the insulating layer 13 for protecting the display electrode 12 provided on the glass substrate 11 on the panel display surface side is covered as in the first embodiment. As the protective film 32, for example, abrasive grains made of glass beads having a particle diameter of about 20 μm from a position spaced about 10 cm away from the surface of a magnesium oxide (MgO) film similar to the prior art are applied at a pressure of 120 g / g with compressed air of 2 atm. A structure using a magnesium oxide (MgO) film that is sprayed at a flow rate of min to roughen the transmittance of visible light (wavelength: 550 nm) to 75% and reflect or scatter visible light. To do.
[0019]
FIG. 2 is a cross-sectional perspective view of an essential part for explaining a third embodiment of the protective film covering the upper part of the insulating layer for protecting the display electrodes provided on the display surface side glass substrate constituting the plasma display panel of the present invention. .
[0020]
As a third embodiment, as shown in FIG. 2, for example, magnesium oxide (MgO) is used as a protective film 33 covering the upper portion of the insulating layer 13 that protects the display electrode 12 provided on the glass substrate 11 on the panel display surface side. In order to make visible light (wavelength: 550 nm) transmittance of the protective film made of a film 65%, magnesium oxide (MgO) absorbs visible light among inorganic pigments: W, Co, Mn, etc. A structure using a colored film that can be formed by an evaporation method using an evaporation source to which (tungsten) is added is used.
[0021]
And the plasma display panel of the first embodiment, the second embodiment and the third embodiment configured as above, the plasma display panel using the conventional protective film made of magnesium oxide (MgO) film, and the conventional plasma display Discharge by applying a discharge voltage to each discharge electrode pair (display electrode) 12 of the plasma display panel with an ND filter attached to the front of the panel, the contrast ratio of the display screen, and the luminance degradation after 2000 hours of discharge The results of measuring the rates are shown in FIG.
[0022]
According to the measurement result of FIG. 3, in any of the plasma display panels of the first embodiment, the second embodiment, and the third embodiment, the luminance deterioration rate after 2000 hours discharge is 28 to 23%, ND Less than a plasma display panel with a filter. In addition, the contrast in the bright room (brightness of 250 lux on the panel surface) is improved because it is less than the luminance deterioration rate of the conventional plasma display panel.
[0023]
In particular, the plasma display panel of the third embodiment using a protective film made of a magnesium oxide (MgO) film added with an inorganic pigment (W) has a bright room contrast almost the same as that of a plasma display panel provided with an ND filter. Therefore, since it is not necessary to use an ND filter, the cost of the panel can be reduced, and the luminance deterioration rate is also improved.
[0024]
Even when a protective film made of a magnesium oxide (MgO) film to which cobalt oxide is added instead of tungsten (W) is used as the inorganic pigment, substantially the same effect as in the third embodiment can be obtained.
[0025]
In the plasma display panels of the first and second embodiments, since the surface of the protective film 31 (32) is roughened, there is a phenomenon that the surface is ion burned by sputtering of discharge gas ions or the like. It is reduced. Furthermore, in the plasma display panel of the third embodiment using the colored protective film 33, even when the luminance of the phosphor is deteriorated due to long-time discharge, the protective film 33 generally has a film thickness due to the sputtering phenomenon during discharge. This is a very small decrease and the light transmittance increases accordingly, so that the deterioration of the luminance of the panel is reduced.
[0026]
In the above embodiment, an example in which a surface display type plasma display panel for color display is targeted has been described, but the present invention is not limited to such a plasma display panel, for example, Needless to say, the present invention can also be applied to a surface display type plasma display panel for monochrome display, a general plasma display panel for color display, or various types of counter electrode type plasma display panels for monochrome display.
[0027]
【The invention's effect】
As is clear from the above description, according to the plasma display panel of the present invention, the protective film whose surface is roughened to reflect or scatter visible light to reduce the transmittance, or the film itself is visible light. By using the protective film made of a magnesium oxide (MgO) film to which inorganic pigments (W, Co, Mn, etc.) are added so as to absorb water, the transmittance of the protective film is 85% or less, preferably It can be reduced to 70% or less, and there is an advantage that the bright room contrast of the display screen of the panel can be improved at a low cost without using an ND filter.
[0028]
Therefore, it is extremely advantageous when applied to a surface discharge type plasma display panel for color display, and has an excellent practical effect.
[Brief description of the drawings]
FIG. 1 is a cross-sectional perspective view of an essential part showing a first embodiment and a second embodiment of a plasma display panel of the present invention.
FIG. 2 is a cross-sectional perspective view of an essential part showing a third embodiment of the plasma display panel of the present invention.
FIG. 3 is a view for comparing and explaining an example of a plasma display panel according to the present invention and a conventional example.
FIG. 4 is an exploded perspective view of an essential part showing an example of a plasma display panel.
[Explanation of symbols]
11 Glass substrate 12 Discharge electrode pair (Display electrode)
13 Insulating layers 31, 32, 33 Protective film

Claims (3)

A protective film for protecting the insulating layer from discharge is provided on the insulating layer covering the electrode disposed on at least one front surface of the pair of substrates opposed to each other through the discharge space. In plasma display panels,
The visible light transmittance of the protective film is at least 85% or less in a portion through which visible light generated based on discharge is transmitted,
Plasma that is configured to reflect or scatter visible light by roughening the surface of at least a portion of the protective film through which visible light generated based on discharge is transmitted. Display panel. A protective film for protecting the insulating layer from discharge is provided on the insulating layer covering the electrode disposed on at least one front surface of the pair of substrates opposed to each other through the discharge space. In plasma display panels,
The visible light transmittance of the protective film is at least 85% or less in a portion through which visible light generated based on discharge is transmitted,
A plasma display panel, wherein at least a portion of the protective film through which visible light generated based on discharge is transmitted is formed of a magnesium oxide film to which an inorganic pigment is added. The protective layer, absorption of visible light, reflection, or by being configured of a member having at least one effect of scattering of claim 1 or 2, characterized in Rukoto to have a less transmittance of 85% The plasma display panel according to any one of the above.

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