JP2003092065A - Discharge electrode material and plasma display panel using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To aim at lowering discharge starting voltage, lowering power consumption, and to improve durability of a discharge electrode material by sputtering. SOLUTION: Of a complex compound XY composed of not less than two different kinds of compounds, used for the discharge electrode material, the compound X is expressed by a compound AQ, where, A is at least a kind selected from Al, Ga, B, and Zn, and Q is made of at least a kind selected from N, O, and S, and the compound Y is expressed by a compound ME, where, M is at least a kind selected from Ta, Hf, Nb, Zr and Ti, and E is made of at least a kind selected from C, N, and B. Or, of a complex compound GL composed of not less than two different compound, used for the discharge electrode material, the compound G is MgO, and the compound L is expressed by MgZ, where, Z is at least a kind selected from Si, O, F, and P.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode having a discharge function, and more particularly to a discharge electrode material used in plasma display panels and the like.

[0002]

2. Description of the Related Art Generally, a plasma display panel has a structure as shown in FIG.

This plasma display panel has a front panel PA1 and a rear panel PA2.

The front panel PA1 is a front glass substrate 11
Scan electrodes 12a and sustain electrodes 12b are alternately formed on the upper surface in a stripe shape, and are further covered with a dielectric glass layer 13 and a protective layer 14.

The back panel PA2 is a back glass substrate 16
An address electrode 17 is formed in a stripe shape on the upper side, an electrode protection layer 18 is formed so as to cover the address electrode 17, and a partition wall 19 is formed in a stripe shape on the electrode protection layer 18 so as to sandwich the address electrode 17. Phosphor layer 2 between partition walls 19
0 is provided and formed.

Then, the front panel PA1 and the rear panel PA2 are bonded to each other, and a discharge gas is enclosed in the space 30 partitioned by the partition wall 19 to form a discharge space. It should be noted that the phosphor layer 20 is usually formed by sequentially stacking phosphor layers of three colors of red, green and blue for color display.

In the discharge space 30, a discharge gas, which is a mixture of neon and xenon, is usually 0.67.
It is sealed at a pressure of about 10 ⁵ Pa.

Next, a driving method of the plasma display panel will be described.

FIG. 2 is a block diagram showing a configuration of a driving circuit of the plasma display panel.

The driving circuit includes an address electrode driving unit 220.
And a scan electrode driver 230 and a sustain electrode driver 240.

An address electrode driver 220 is connected to the address electrode 17 of the plasma display panel, a scan electrode driver 230 is connected to the scan electrode 12a, and a sustain electrode driver 240 is connected to the sustain electrode 12b.

Generally, in an AC type plasma display panel, one frame image is displayed in a plurality of subfields (S.
F.) is used to express gradation. Then, in this method, in order to control the discharge of gas in the cell, 1S. F. Is further divided into four periods. The four periods will be described with reference to FIG. FIG. 3 is a drive waveform during 1SF.

In FIG. 3, the setup period 250
Then, wall charges are uniformly accumulated in all cells in the PDP in order to facilitate discharge. In the address period 260, the writing discharge of the cell to be turned on is performed. In the sustain period 270, the cell written in the address period 260 is lit and the lit state is maintained. Erase period 280
Then, the wall charge is erased to stop the lighting of the cell.

In the setup period 250, the scan electrode 12
A higher voltage than that of the address electrode 17 and the sustain electrode 12b is applied to a to discharge the gas in the cell. Since the charges generated thereby are accumulated on the wall surface of the cell so as to cancel the potential difference between the address electrode 17, the scan electrode 12a and the sustain electrode 12b, negative charges are generated as wall charges on the surface of the protective film near the scan electrode 12a. In addition, positive charges are accumulated as wall charges on the surface of the phosphor layer near the address electrodes and the surface of the protective film near the sustain electrodes. Due to this wall charge, a wall potential having a predetermined value is generated between the scan electrode and the address electrode and between the scan electrode and the sustain electrode.

In the address period 260, when the cell is lit, a voltage lower than that applied to the address electrode 17 and the sustain electrode 12b is applied to the scan electrode 12a, that is, between the scan electrode and the address electrode in the same direction as the wall potential. A voltage is applied to the scan electrodes and a voltage is applied between the scan electrodes and the sustain electrodes in the same direction as the wall potential to generate the write discharge. As a result, negative charges are accumulated on the surface of the phosphor layer and the protective layer, and positive charges are accumulated as wall charges on the surface of the protective layer near the scanning side electrode. As a result, a wall potential having a predetermined value is generated between the sustain and scan electrodes.

In the sustain period 270, the scan electrode 12a is formed.
By applying a voltage higher than that of the sustain electrode 12b, that is, by applying a voltage between the sustain electrode and the scan electrode in the same direction as the wall potential, the sustain discharge is generated.
As a result, cell lighting can be started. Then, by applying a pulse so that the polarities of the sustain electrodes and the scan electrodes are alternately switched, it is possible to intermittently emit pulsed light.

In the erase period 280, by applying a narrow erase pulse to the sustain electrode 12b, incomplete discharge occurs and the wall charges disappear, so that erase is performed.

[0018]

By the way, as described above, conventionally, the dielectric protective layer 14 of the plasma display panel has a function of protecting the original dielectric and, at the same time, the AC type plasma as described above. In the display panel, it is the part that is directly exposed to the discharge space, and the function as an effective electrode becomes important. Therefore, this dielectric protective layer requires a discharge electrode material having excellent spatter resistance and electron emission characteristics. At present, magnesium oxide (MgOx) is used as a discharge electrode material for the dielectric protection layer.
O) is used.

This is because it was considered that the two requirements of the above-mentioned discharge electrode material, that is, the sputtering resistance and the electron emission characteristic, were relatively good as compared with other materials.

However, the conventionally used MgO film is sputtered by the impact of ions and gradually becomes thin to shorten the life as a product, or the film quality is difficult to control, and the discharge start voltage is further improved by further improving the electron emission characteristics. It is said that it is difficult to realize a PDP device with higher efficiency, such as difficulty in lowering.

Therefore, the present invention has been made for the purpose of providing a discharge electrode material having sputter resistance and electron emission characteristics superior to those of MgO.

[0022]

In order to achieve the above object, the present invention uses a discharge electrode material which is a wide band gap material, a compound X having excellent electron emission characteristics, and a high melting point material, which is sputter resistance. By using the composite compound XY made of the excellent compound Y, a discharge electrode material having excellent electron emission characteristics and excellent spatter resistance can be realized.

In order to achieve the above object, the compound G is represented by MgO, the compound L is represented by MgZ, and the standard energy of formation DH <-1095 kJ · mol ^-1 (Mg (O
By using the composite compound GL composed of the compound H) ₂ ), a discharge electrode material having excellent electron emission characteristics and excellent spatter resistance can be realized.

As a result, as a discharge electrode material used for the dielectric protective layer, a film having very good electron emission characteristics and sputtering resistance can be obtained as compared with conventional MgO.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an AC type plasma display panel according to an embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a partial perspective view of an AC surface discharge type plasma display panel 1 (hereinafter, simply referred to as PDP 1).

As described above, the PDP 1 discharges the discharge space 30 by applying a pulsed voltage to each electrode.
It is an AC surface discharge type PDP that allows the visible light of each color that is generated inside and is generated on the side of the rear panel PA2 with the discharge to pass from the main surface of the front panel PA1.

The front panel PA1 covers the front surface 11a on the front glass substrate 11 in which a plurality of pairs of scan electrodes 12a and sustain electrodes 12b are arranged in stripes (one pair is shown for convenience of illustration). The dielectric glass layer 13 is formed, and the protective layer 14 is further formed so as to cover the dielectric glass layer 13.

The rear panel PA2 protects the address electrodes 17 on the rear glass substrate 16 arranged in stripes so that the address electrodes 17 are orthogonal to the scan electrodes 12a and the sustain electrodes 12b. In addition, an electrode protective layer 18 having a function of reflecting visible light to the front panel side is formed, and a partition wall is formed on the electrode protective layer 18 so as to extend in the same direction as the address electrode 17 and sandwich the address electrode 17. 19 are provided upright, and a phosphor layer 20 is further disposed between the partition walls 19.

The PDP having the above structure is driven by using the drive circuit shown in FIG. 2 based on the drive waveform shown in FIG. The address electrodes 17 are connected to the address driver 220, the scan electrodes 12a are connected to the scan electrode driver 230, and the sustain electrodes 12b are connected to the sustain electrode driver 240. In the present invention, the above protective layer 14
The discharge electrode material is used for. Hereinafter, embodiments of the present invention will be described.

Generally, the wide band gap material is a material having a band gap of 1.1 eV or more of Si, but the wide band gap material of the present invention has a band gap of 3 eV or more. It is a material.

(Embodiment 1) In the embodiment described below, in the above-mentioned protective layer 14, in two or more kinds of different composite compounds XY, the compound X is represented by a compound AQ, the A is Al, Ga is at least one selected from B, Zn, Q is at least one selected from N, O and S, and the compound Y is a compound M.
Is represented by E, and M is Ta, Hf, Nb, Zr and T
at least one selected from i, wherein E is C, N
And a case where a discharge electrode material consisting of at least one selected from B and B is used.

Tables 1 and 2 show discharge electrode materials within the scope of the embodiment of the present invention.

[0034]

[Table 1]

In Table 1, the compound AQ is used as the compound X,
FIG. 3 shows respective discharge starting voltage and film thickness reduction rate when the compound ME is used as the compound Y and the discharge electrode material represented by the composite compound XY is used.

[0036]

[Table 2]

Table 2 shows the discharge start voltage and the film thickness reduction rate with respect to the surface area ratio of the compound X and the compound Y in the composite compound XY shown in Table 1.

The discharge starting voltage and the film thickness reduction rate were used for the evaluation of the discharge electrode material using each of the composite compounds XY as a protective layer. As the discharge start voltage, the voltage value required for in-plane discharge at the scan electrode 12a and the sustain electrode 12b of the PDP 1 is MgO.
Values when the discharge start voltage is set to 100 for MgO. Accordingly, if the discharge starting voltage is 100 or less, it can be considered that the discharge starting voltage is lower than that of MgO. In addition, the discharge start 10
The film thickness reduction rate after 00 hours is shown when the change amount of MgO is 100. Accordingly, it can be considered that the sputtering resistance is improved as compared with MgO when the film thickness reduction rate is 100 or less.

Further, in Table 2, the discharge starting voltage is Mg
When it is equal to or less than O, it is evaluated as ◯ or ⊚, and when it is more than O, it is evaluated as x. Further, when the film thickness reduction rate is equal to or less than that of MgO, it is marked with ◯ or ⊚, and when it is more than that, it is marked with x.

The compound X shown in Table 1 is a wide band gap material having a band gap of 3 eV regardless of the composition.

According to Table 1, a decrease in discharge starting voltage and a decrease in film thickness reduction rate are observed in the protective layers using all the composite compounds XY.

This is because, by using the composite compound XY, each compound can sufficiently exhibit its excellent characteristics, and each compound has an effect of compensating for the inferior characteristics. Therefore, the protective layer has excellent sputter resistance and electron emission characteristics.

Furthermore, by using a material that is a wide band gap material for the compound X, the difference in energy between the energy level of the conduction band width and the vacuum level becomes small, or the vacuum level becomes the conduction band. The state becomes lower than the energy level of width, that is, the electron affinity becomes negative. This allows electrons existing on the surface of the compound to emit electrons without giving a large amount of energy, and has an effect of improving electron emission characteristics. The compound Y has a high melting point, so It has the effect of improving the sputterability.

Further, according to Table 2, the discharge start voltage and the film thickness reduction rate change depending on the difference in the surface area ratio x / y between the compound X and the compound Y, and the surface area ratio x / y is 1 <x.
In the range of / y <100, the discharge start voltage is lowered and the spatter resistance is improved.

This is because by setting the surface area ratio x / y between the compound X and the compound Y in the range of 1 <x / y <100, the compound having excellent electron emission characteristics occupies more than half of the total surface area. This is because the protective layer has excellent electron emission characteristics and excellent spatter resistance. In other cases, the electron emission characteristic is deteriorated, and the protective layer is excellent only in spatter resistance.

In the embodiment of the present invention, as the compound Y, TaC, HfC, ZrC, HfN and Ti which are high melting point materials are used.
N and NbB were used, but from FIG. 6, all of these compounds are higher than the melting point of MgO. Therefore, compared with MgO,
Improved spatter resistance. Therefore, by using another compound having a higher melting point than MgO for the compound Y,
The same effect can be obtained.

The composite compounds shown in Tables 1 and 2 contain F, C as elements other than A, Q, M and E.
At least one selected from 1, Ar, H, He, Ne, Kr, and Xe is contained in an atomic percentage of 0.6% or less. Therefore, even if an element other than A, Q, M and E is contained as an impurity, it is not affected as long as the atomic percentage is 0.6% or less.

Further, in the embodiment of the present invention, the above sample was prepared by the sputtering method using an alloy target and a powder target. However, the method is not limited to this method, and the sputtering method using the target having the above composition or Similarly, the same effect can be obtained by an electron beam evaporation method using an evaporation source having the above composition.

(Embodiment 2) In the embodiment described below, in the composite compound GL composed of two or more different compounds in the protective layer 14, the compound G is MgO and the compound is L is represented by MgZ, and Z
Is a case where a discharge electrode material made of at least one selected from Si, O, F, and P is used.

Tables 3 and 4 show discharge electrode materials within the scope of the embodiment of the present invention.

[0051]

[Table 3]

Table 3 shows discharge start voltage and XRD results when MgO was used as the compound G and a discharge electrode material represented by the composite compound GL using the compound L was used.

[0053]

[Table 4]

Table 4 shows the discharge start voltage and the XRD result with respect to the surface area ratio of the compound G and the compound L in the composite compound GL shown in Table 3.

For the evaluation of the discharge electrode material using each compound as a protective layer, the discharge starting voltage was the scan electrode 1 of the PDP 1.
The voltage value required for in-plane discharge between 2a and sustain electrode 12b is compared with that of MgO, and the discharge start voltage is shown when MgO is 100. As a result, the discharge start voltage is 100
If it is below, it can be considered that the discharge starting voltage is lower than that of MgO. For the sputtering resistance, the substance on the film surface 1000 hours after the start of discharge was evaluated using XRD. If it was the same as the substance before the start of discharge, it was evaluated as ◯, and if it was ◯, it was considered that the sputtering resistance was improved. be able to.

Further, in Table 4, the discharge starting voltage is Mg
When it is equal to or less than O, it is evaluated as ◯ or ⊚, and when it is more than O, it is evaluated as x. Also, as in Table 3, for the spatter resistance, the substance on the film surface 1000 hours after the start of discharge was evaluated using XRD. Can be considered improved.

According to Table 3, as in the case of the first embodiment, the discharge start voltage is lowered and the spatter resistance is improved in all the protective layers using the respective compositions.

When MgO is once separated from the surface of the protective layer due to the sputtering effect, reacts with CO ₂ and H ₂ O existing in the panel to change into MgCO ₃ and Mg (OH) ₂ , and is attached to the protective layer again. Is a compound different from MgO. this is,
Standard generation energy DH of MgO is -601 kJ · mo
whereas a l ^-1, MgCO ₃ or Mg (OH) ₂ of the standard formation energy DH respectively -924kJ · mo
l ⁻¹ and −1095 kJ · mol ⁻¹ . Therefore, Mg
O reacts with CO ₂ and H ₂ O to generate MgCO ₃ and Mg (O
Since it is more stable when H) ₂ is changed, it becomes a compound different from the original MgO on the surface of the protective layer due to the sputtering effect.

On the other hand, the standard production energy ΔH <−
By using a compound in the range of 1095 kJ · mol ⁻¹ (Mg (OH) ₂ ), even if it is separated from the surface of the protective film by the sputtering effect, it does not react with CO ₂ or H ₂ O existing in the panel, When it adheres to the surface of the protective layer again, it becomes the original compound. This provides a protective layer with improved sputter resistance. In fact, the compound L shown in Table 3 has a standard production energy ΔH of ΔH <-1095 kJ · mol ⁻¹ (Mg
It is in the range of (OH) ₂ ) and the results of the discharge start voltage and the XRD of the composite compound GL using the compound L are good, and the discharge start voltage is lowered and the spatter resistance is improved.

Further, according to Table 4, the discharge start voltage and the substance on the film surface were changed due to the difference in the surface area ratio g / l between the compound G and the compound L, and the surface area ratio g / l was 1 <
In the range of g / l <100, the discharge start voltage is lowered and the spatter resistance is improved.

This is because by setting the surface area ratio g / l of the compound G to the compound L in the range of 1 <g / l <100, the compound having excellent electron emission characteristics occupies more than half of the total surface area. This is because the protective layer has excellent electron emission characteristics and excellent spatter resistance. In other cases, the electron emission characteristic is deteriorated, and the protective layer is excellent only in spatter resistance.

In the examples of the present invention, the above sample was prepared by a sputtering method using an alloy target and a powder target. However, the method is not limited to this method, and a sputtering method using a target having the above composition or the like. In addition, the same effect can be obtained by the electron beam evaporation method using the evaporation source having the above composition.

(Embodiment 3) FIGS. 4 and 5 are film structure diagrams in Embodiment 3 of the present invention. FIG. 4 is a view of the film surface, and FIG. 5 is a cross-sectional view of the film.

In two or more different complex compounds XY, the compound X is represented by the compound AQ, and the A is A
1, Ga, B and Zn, Q is at least one selected from N, O and S, the compound Y is represented by a compound ME, and the M is Ta, A discharge electrode material comprising at least one selected from Hf, Nb, Zr and Ti, and E comprising at least one selected from C, N and B has a structure as shown in FIG.

FIG. 4 shows a state in which the compound Y is scattered. The compound X must be present in the cell because it has the function of causing discharge by the compound X having excellent electron emission characteristics and lowering the discharge start voltage.
In a cell in which the inside of the cell is the compound Y, no light is emitted on the screen. Therefore, with the structure shown in FIG. 4, the inside of the cell is the composite compound XY, and it is possible to discharge without a non-lighted portion.

In the case of using the sputtering method, the discharge electrode having such a structure can be prepared by preparing the substrate at the time of film formation at a low temperature, preferably at 200 ° C. or lower. Further, similar effects can be obtained not only by this method but also by an electron beam evaporation method.

In the composite compound GL composed of two or more different compounds, the compound G is MgO, the compound L is represented by MgZ, Z is Si,
The discharge electrode material consisting of at least one selected from O, F, and P has a structure as shown in FIG.

FIG. 4 shows a state in which the compound L is scattered. Since the compound L has a function of improving the sputtering resistance, the compound L must be present in the cell. In a cell in which the inside of the cell is the compound G, that is, when the inside of the cell is MgO, it is the same as the conventional case. Therefore, with the structure as shown in FIG. 4, all of the inside of the cell is the composite compound GL, and it is possible to improve the sputtering resistance.

As shown in FIG. 5, even when the discharge electrode material is formed on a substrate and has a composition modulation structure in a direction perpendicular to the substrate surface, the composite compound XY and If it is the complex compound GL,
It is a discharge electrode material with excellent electron emission characteristics and spatter resistance.

The film structure of the discharge electrode material is preferably columnar structure. It is considered that this is because the surface area where electrons are emitted toward the discharge space 30 can be made large, and as a result, trigger electrons for address discharge and sustain discharge are easily emitted. The columnar structure portion has a crystal width of 50 to 3000 nm, and when the columnar portion has an inclination α with respect to the film surface,
It is desirable that 30 <α <90. Although the cause of this phenomenon has not been clarified yet, when the discharge electrode material has a shape in this range, the electron emission characteristics are further improved.

Further, the film in which the compound X is preferentially oriented to the (002) plane and the compound GL is preferentially oriented to any of the (111), (200) and (220) planes showed good electron emission characteristics. . Also here, the cause of the phenomenon has not been clarified yet.

The discharge electrode material has a film thickness of 1000.
It is desirable that the thickness is less than or equal to nm. Because 1000n
This is because when the thickness is m or more, the transmittance of the protective layer is reduced, which leads to a reduction in the brightness of image display.

[0073]

As described above, according to the present invention, by using two or more different kinds of composite compounds XY and materials represented by the composite compound GL as the discharge electrode material,
It is possible to supply a discharge electrode having excellent electron emission characteristics and excellent spatter resistance.

Further, two or more different kinds of composite compounds XY
Also, the discharge electrode material represented by the composite compound GL is used as a PD.
By using it as a protective film for P, a highly efficient PDP device can be realized.

[Brief description of drawings]

FIG. 1 is a perspective view of a portion showing a conventional plasma display panel.

FIG. 2 is a block diagram showing a connection state between a plasma display panel and a driving circuit, which is common to the conventional art and the present invention.

FIG. 3 is a time chart showing drive waveforms of a plasma display panel common to the conventional art and the present invention.

FIG. 4 is a surface view of a discharge electrode of this example.

FIG. 5 is a cross-sectional view of a discharge electrode of this example.

FIG. 6 is a diagram showing melting points of high melting point materials according to the present invention.

[Explanation of symbols]

PA1 front panel PA2 rear panel 11 Front glass substrate 11a surface 12a scanning electrode 12b Sustain electrode 12c discharge gap 13 Dielectric glass layer 14 Protective layer 16 Rear glass substrate 17 address electrodes 18 Electrode protection layer 19 partitions 20 Phosphor layer 30 discharge space 220 address driver 230 Scan electrode driver 240 Sustain electrode driver

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Jun Kuwata             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Tetsuhisa Yoshida             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Hideaki Adachi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Kazuyuki Hasegawa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Koichi Kodera             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Hidetaka Higashino             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5C015 HH02                 5C040 FA01 GB03 GB14 GC18 KB22

Claims (11)

[Claims] 1. In a composite compound XY composed of two or more different compounds, the compound X is represented by a compound AQ, and the A is at least one selected from Al, Ga, B and Zn, The Q is at least one selected from N, O and S, the compound Y is represented by a compound ME, the M is at least one selected from Ta, Hf, Nb, Zr and Ti, A discharge electrode material in which E is at least one selected from C, N and B. 2. The discharge electrode material according to claim 1, wherein the compound X is a wide band gap material and the compound Y is a high melting point material. 3. The discharge electrode material according to claim 1, wherein the surface area ratio x / y of the compound X and the compound Y is in the range of 1 <x / y <100. 4. In a composite compound GL composed of two or more different compounds, the compound G is MgO, the compound L is represented by MgZ, and Z is Si.
A discharge electrode material comprising at least one selected from O, F, and P. 5. The discharge electrode material according to claim 1, wherein the surface area ratio g / l of the compound G and the compound L is in the range of 1 <g / l <100. 6. The discharge electrode material according to claim 1, which is formed on a substrate and has a composition modulation structure in a direction perpendicular to the substrate surface. 7. The discharge electrode material according to claim 1, which is formed on a substrate and has a columnar structure. 8. The width of a crystal having a columnar structure is 50 nm or more.
It is 3000 nm, The discharge electrode material of Claims 1-7. 9. The discharge electrode material according to claim 1, wherein the columnar structure has a range of 30 <α <90 degrees, where α is an inclination with respect to the substrate surface. 10. A first substrate in which a plurality of electrode pairs of a first electrode and a second electrode arranged in stripes are arranged in parallel, and the plurality of electrode pairs are covered with a dielectric layer. And the third
2. A plasma display panel in which the second substrate on which the electrodes are arranged in a stripe pattern are arranged to face each other with a partition wall interposed therebetween, and the dielectric layer is formed.
9. A plasma display panel, which is coated with the discharge electrode material according to item 9. 11. A plasma display, wherein the film thickness of the discharge electrode material according to claim 1 is 1000 nm or less.