JP3688102B2 - Flat display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flat display panel. More particularly, the present invention relates to a flat display panel provided with a discharge protective layer that has sputtering resistance and good electron emission characteristics.
[0002]
[Prior art]
As a flat display panel, a plasma display panel is generally known, and this plasma display panel is generally a pair of substrates, electrodes, barrier ribs, phosphor layers, dielectric layers, and discharge protection layers that are opposed to each other with a discharge space interposed therebetween. And components such as discharge gas. Here, the discharge protective layer is formed so as to be in contact with the discharge space in order to prevent deterioration of the components of the PDP such as the dielectric layer and the electrode due to ion bombardment during discharge. Therefore, the material and film quality of the discharge protective layer are important factors for stabilizing the display, facilitating driving, and extending the life.
[0003]
As a material for the discharge protection layer, magnesium oxide is generally used. Magnesium oxide is a so-called high γ substance having a strong sputter resistance and a large secondary electron emission coefficient (electron affinity around 0.5 eV). Therefore, when magnesium oxide is used for the discharge protection layer, the discharge start voltage is lowered, the allowable range of the drive voltage is widened, and driving is facilitated.
[0004]
[Problems to be solved by the invention]
However, since the power consumption increases as the display surface is increased in size and definition, it has been desired to develop a discharge protective layer having a driving voltage having a larger electron emission coefficient (smaller electron affinity) than that of magnesium oxide. In addition, development of a discharge protective layer capable of suppressing deterioration over time has been desired in order to realize further long-time display.
[0005]
[Means for Solving the Problems]
Thus, according to the present invention, in a panel configuration including a discharge electrode and a discharge protection layer that insulates and protects the discharge electrode from the discharge space, the discharge protection layer is formed on the magnesium oxide layer and 10 ⁴ to 10 ¹² pieces. / cm Ri configuration Narudea ing of a plurality of islands of diamond present in the ^second density, individual islands of diamond, have a shape of height 0.01~100μm and diameter 0.01~100μm flat display panel, wherein to Rukoto is provided.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention can be applied to a plasma display panel (hereinafter referred to as PDP), a plasma address liquid crystal, and the like. Among these, it is preferable to apply to PDP.
The substrate used in the present invention can be appropriately selected according to the field of use of the substrate. For example, a substrate such as a silicon substrate, a quartz substrate, or a glass substrate, or an electrode, an insulating film, a dielectric layer, or the like on these substrates. And a substrate on which the desired composition is formed.
[0008]
Next, a discharge protective layer is formed on the surface of the substrate on the discharge space side. For example, in the case of a surface discharge type PDP, the surface of the substrate on the discharge space side means the dielectric layer of the display surface side substrate. In the present invention, the discharge protective layer is
(1) It consists of a magnesium oxide layer and island-shaped diamond formed thereon, or consists of a magnesium oxide layer and a diamond-like carbon (hereinafter referred to as DLC) layer formed thereon, or
(2) Consists of a DLC layer.
In the present specification, the configuration including the DLC layer is a reference example.
[0009]
First, the discharge protective layer (1) will be described (FIGS. 1A and 1B). In this case, the magnesium oxide layer 2 is laminated on the substrate 1. The formation method of a magnesium oxide layer is not specifically limited, Any well-known methods, such as CVD method and a vapor deposition method, can be used. The thickness of the magnesium oxide layer is preferably in the range of 0.05 to 100 μm. The magnesium oxide layer preferably has a phase center cubic type crystal structure.
[0010]
Next, island-shaped diamond 3 (FIG. 1A) or DLC layer 4 (FIG. 1B) is formed on the magnesium oxide layer.
First, each of the island-shaped diamonds preferably has a height of 0.01 to 100 μm and a diameter of 0.01 to 100 μm, and 10 ⁴ to 10 ¹² diamonds / cm ² exist. preferable. Here, since diamond has an electron affinity of about −0.7 eV, which is lower than that of magnesium oxide, it has a property of easily releasing electrons. Furthermore, since the diamond is in an island shape, electrons are more likely to be emitted from the tip, and the drive voltage can be further reduced.
[0011]
As a method for forming island-shaped diamond, any method known in the art can be used. For example, ECR microwave plasma CVD method, microwave plasma CVD method, hot filament CVD method and the like can be mentioned. As a raw material gas used for these CVD methods, a mixed gas of a carbon raw material gas such as methane, acetylene, acetone, methanol, ethanol, CO and hydrogen gas is preferable. Further, by setting the carbon source gas / hydrogen gas to 10% (volume ratio) or less, preferably 0.05 to 3%, the formed diamond can be in the (111) orientation. If this (111) -oriented diamond is used, electrons can be more easily emitted, so that the driving voltage can be further reduced.
[0012]
On the other hand, DLC is also referred to as amorphous carbon. For example, J. Vac. It is described as being used as a protective layer. Since this DLC has excellent properties such as high hardness, low friction, wear resistance, high light transmission, chemical stability, etc., by installing it on the discharge space side exposed to plasma of flat display panel, It is possible to prevent the flat display panel from being deteriorated with time. The thickness of the DLC layer is preferably 0.001 to 10 μm. The DLC layer preferably contains sp ³ bond crystals as a main component. Here, the main component means at least 50% by weight or more, preferably 60% by weight or more. Further, impurities such as nitrogen may be contained at a ratio of 1% by weight or less.
[0013]
Any method known in the art can be used as a method for forming DLC. For example, a vapor deposition method such as an ion beam vapor deposition method, a sputtering method such as a DC magnetron sputtering method, a plasma CVD method using a hot filament, an RF, an ECR power source or the like as a plasma source may be used.
Note that island-shaped diamond may be further formed on the DLC layer.
[0014]
Next, the discharge protective layer (2) will be described (FIG. 2). In this case, a DLC layer 5 is formed on the substrate 1 as a discharge protection layer instead of the magnesium oxide layer. The thickness of the DLC layer, the manufacturing method, and the like can be set to the same conditions as in the above (1). Further, island-shaped diamond may be further formed on the DLC layer.
Next, an application example of the discharge protective layer of the present invention to a flat panel display is shown below. Hereinafter, a PDP will be described as an example of a flat panel display, but the present invention is not limited to this.
[0015]
FIG. 3 is a diagram showing an example of a PDP that can suitably use the present invention. The configuration of FIG. 3 is an example, and the present invention is not limited to this, and can be applied to any type of PDP such as an AC type and a DC type.
FIG. 3 is a schematic perspective view corresponding to one pixel of a general indirect discharge type (AC type) surface discharge type PDP, which belongs to the reflection type according to the arrangement of the phosphor layers, and has a three-electrode structure. PDP is shown.
[0016]
In the PDP 11 of FIG. 3, a pair of substrates 12 and 15 are arranged to face each other. As the substrate, a glass substrate, a quartz substrate, a silicon substrate, or the like can be used. A pair of display electrodes (sustain electrodes) X and Y are formed on the substrate 12 in parallel, and a dielectric for alternating current (AC) driving that maintains a discharge with a wall electrode on the substrate 12 so as to cover the display electrodes X and Y. A body layer 13 is formed, and a discharge protection layer 14 is formed on the dielectric layer 13. The dielectric layer can be generally formed by applying and baking a low melting point glass paste. As described above, this discharge protective layer is composed of a magnesium oxide layer and island-shaped diamond or DLC layer, or is composed of a DLC layer.
[0017]
On the other hand, a plurality of stripe-shaped address electrodes A are formed on the substrate 15 at positions orthogonal to the display electrodes X and Y when viewed in plan, and the dielectric layer 16 is formed on the substrate 15 so as to cover the address electrodes A. Are stacked. Here, the address electrode is composed of Ag, Au, Al, Cu, Cr, and their laminates (for example, Cr / Cu / Cr), and the like, by combining a film forming method such as a sputtering method and a vapor deposition method with an etching method. The desired number, thickness, width and interval can be formed.
[0018]
Further, a plurality of stripe-shaped partition walls 17 are formed between adjacent address electrodes A and parallel to the address electrodes A. The partition wall 17 can be formed by the pattern forming method of the present invention.
Next, a phosphor layer 18 is formed on the side surface of the adjacent partition wall 17 and the address electrode A. In the present invention, the substrate 15, the address electrode A, the dielectric layer 16, the partition wall 17, and the phosphor layer 18 correspond to the base.
[0019]
Next, reference numeral 19 denotes a discharge space, which is partitioned for each unit light emitting region (hereinafter referred to as EU) in the extending direction of the display electrodes X and Y, and the gap dimension is defined. The discharge space 19 is filled with a desired discharge gas.
In the PDP 11, as shown in FIG. 3, in each of the three EUs corresponding to one pixel EG, a selected discharge cell for selecting display or non-display is determined at the intersection of the display electrode Y and the address electrode A. Yes. A main discharge cell is defined between the display electrodes X and Y.
[0020]
Here, the phosphor layer 18 is provided between the barrier ribs 17 on the substrate 15 on the opposite side of the display electrodes X and Y in order to avoid impact caused by ions generated by surface discharge. The phosphor layer 18 generally emits light by converting vacuum ultraviolet rays generated by surface discharge of the main discharge cell into visible light. The light emitted from the phosphor layer 18 passes through the dielectric layer 13 and the substrate 12 and is emitted to the outside. That is, in the PDP 11, the outer surface of the substrate 12 is the display surface D.
[0021]
Since the display electrodes X and Y are arranged on the display surface D side with respect to the phosphor layer 18, a wide transparent conductive film 20 is used in order to widen the surface discharge and minimize the shielding of the display light. And a narrow metal film (bus electrode) 21 for compensating the conductivity. The transparent conductive film is made of a metal oxide such as ITO (indium oxide + tin oxide) or Nesa (tin oxide), for example, and a desired number, thickness, width by combining a film formation method such as vapor deposition and an etching method. And can be formed at intervals. On the other hand, the bus electrode is composed of Ag, Au, Al, Cu, Cr, and their laminates (for example, Cr / Cu / Cr), etc., by combining a film forming method such as a sputtering method and a vapor deposition method with an etching method. The desired number, thickness, width and interval can be formed.
[0022]
As described above, the PDP 11 covers the display electrodes X and Y, and the substrate 12 (display-side substrate) having the dielectric layer 13 for maintaining discharge and the substrate 15 (having the partition wall 17 for partitioning the discharge space 19 ( The two substrates (back substrate) are bonded together.
[0023]
【Example】
Example 1 and Comparative Example 1
First, a pair of display electrodes X and Y was formed on the glass substrate 12. The display electrodes X and Y are each a laminate of a transparent conductive film 20 made of ITO and a metal film 21 made of a laminate of Cr / Cu / Cr. Next, a dielectric layer 13 made of low-melting glass of 50 μm was laminated on the glass substrate 12 on which the display electrodes X and Y were formed. Further, a magnesium oxide layer was laminated on the dielectric layer.
[0024]
Thereafter, a 20 nm DLC layer was laminated on the magnesium oxide layer by DC magnetron sputtering. The lamination conditions of the DLC layer were as follows: the lamination temperature was room temperature, the sputtering target was a sintered graphite, the sputtering gas was Ar gas, and the power density was 0.25 W / cm ² . When this DLC layer was examined by Raman spectroscopy, it was found that about 60 wt% of sp ³ -bonded crystals were contained.
[0025]
According to the above method, the PDP display side substrate in which the discharge protective layer 14 was formed of a laminate of a magnesium oxide layer and a DLC layer could be formed.
Next, an address electrode A made of a Cr / Cu / Cr laminate was formed on the glass substrate 15. Next, a dielectric layer 16 made of low melting point glass of 50 μm was laminated on the glass substrate on which the address electrode A was formed. A partition wall material layer was laminated on the dielectric layer 16, patterned by sandblasting, and then cured by heat treatment to form partition walls 17. Next, the rear substrate could be formed by forming the phosphor layer 18 on the side wall of the partition wall 17 and the dielectric layer 16 between the partition walls.
[0026]
A display-side substrate and a rear substrate are bonded so that the display electrodes X and Y and the address electrode A are orthogonal to each other, and a discharge gas is sealed in the discharge space 19, whereby the PDP 11 as shown in FIG. .
As Comparative Example 1, a PDP in which a DLC layer was not formed as a discharge protective layer, that is, only a magnesium oxide layer was also manufactured.
[0027]
When the PDPs of Example 1 and Comparative Example 1 were driven, the PDP of Example 1 could be operated with a drive voltage 0.9 times that of the PDP of Comparative Example 1. The driving voltage of the PDP of Example 1 was reduced because the DLC layer has a low electron affinity and easily emits electrons, so that secondary electrons necessary for plasma emission can be emitted at a lower voltage. .
[0028]
A PDP formed in the same manner as in Example 1 except that the DLC layer was set to 60 nm could be operated with a drive voltage 0.9 times that of the PDP in Comparative Example 1.
Example 2
A PDP was produced in the same manner as in Example 1 except that island-shaped diamond was formed on the magnesium oxide layer by the following method instead of the DLC layer.
[0029]
The island-like diamond had an individual diamond diameter of about 1 μm and a height of about 0.5 μm, and a density of 10 ⁸ pieces / cm ² by ECR microwave plasma CVD. The island-shaped diamond was formed using the apparatus shown in FIG. In FIG. 4, reference numeral 31 is a magnetron, 32 is a reaction gas introduction path, 33 is a magnet coil, 34 is a plasma generation chamber, 35 is a substrate, and 36 is a substrate transport mechanism.
[0030]
When the formed island-shaped diamond was examined by Raman spectroscopy, it was found that the island-shaped diamond did not contain an amorphous component and was formed only from the diamond component. Further, even when the substrate was immersed in pure water and washed with ultrasonic waves, no island-like diamonds were observed to drop off.
When the PDPs of Example 2 and Comparative Example 1 were driven, the PDP of Example 1 could be operated with a driving voltage 0.85 times that of the PDP of Comparative Example 1. The reason why the driving voltage of the PDP in Example 1 is reduced is considered to be that the tip of the island-shaped diamond has an acute angle and the electric field tends to concentrate on this portion. Further, it is considered that diamond itself has a small electron affinity and easily emits electrons, so that secondary electrons necessary for plasma emission can be emitted at a lower voltage.
[0031]
【The invention's effect】
According to the present invention, since the DLC layer or the island-shaped diamond is formed on the side in contact with the discharge space, the flat display panel in which the driving voltage can be reduced and the deterioration of the discharge protective layer with time is suppressed. Can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a main part of a flat display panel according to the present invention.
FIG. 2 is a schematic cross-sectional view of a main part of the flat display panel of the present invention.
FIG. 3 is a schematic perspective view of a PDP of the present invention.
FIG. 4 is a schematic view of an island-shaped diamond forming apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Base body 2 Magnesium oxide layer 3 Island-like diamond 4, 5 DLC layer 11 PDP
12, 15 Substrate 13, 16 Dielectric layer 14 Discharge protection layer 17 Partition 18 Phosphor layer 19 Discharge space 20 Transparent conductive film 21 Metal film 31 Magnetron 32 Reactive gas introduction path 33 Magnet coil 34 Plasma generation chamber 35 Base 36 Base transport mechanism A Address electrode D Display surface X, Y Display electrode

Claims (2)

In a panel configuration including a discharge electrode and a discharge protective layer that insulates and protects the discharge electrode from the discharge space, the discharge protective layer is formed on the magnesium oxide layer and has a density of 10 ⁴ to 10 ¹² pieces / cm ^2. Organization Narudea ing of a plurality of islands of diamond that is, individual islands of diamond, characterized in Rukoto to have a shape of height 0.01~100μm and diameter 0.01~100μm Flat display panel. Island-like diamond has a flat display panel according to claim 1 which is formed by a CVD method.

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