JP2007317486A - Plasma display panel, and method and device for manufacturing plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display panel with a low discharge voltage and having a high sputtering resistance, and to provide a method and device for manufacturing the plasma display panel. <P>SOLUTION: Since the main component of a protection film 14 formed on a PDP 100 contains SrO and MgO and the concentration of MgO in the protection film is made 30 mol% or more and 70 mol% or less, a PDP 100 having a low discharge voltage and a high sputtering resistance and capable of shortening an aging time can be obtained. Furthermore, a forming process to a sealing process of the protection film are carried out in a vacuum atmosphere, moisture absorption of the protection film can be prevented effectively. Thereby, a long lifetime of the PDP 100 can be achieved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma display panel, a plasma display panel manufacturing method, and a plasma display panel manufacturing apparatus.

  A plasma display panel (PDP) includes a front substrate on which sustain electrodes and scan electrodes are formed, and a rear substrate on which address electrodes and phosphors are formed. Both substrates are bonded together by a sealing material disposed at the peripheral edge, and a discharge gas is sealed between the substrates. When a voltage is applied between the electrodes, the discharge gas is turned into plasma and ultraviolet rays are emitted. The ultraviolet rays are incident on the phosphor to excite the phosphor and emit visible light.

  The sustain electrodes and the scan electrodes are covered with a dielectric layer, and a protective film is formed so as to cover the dielectric layer. This protective film protects the dielectric layer from cations generated by turning the discharge gas into plasma, and is composed of MgO (see, for example, Patent Document 1).

It is known that the voltage (discharge voltage) at the time of discharging the PDP depends on the secondary electron emission coefficient of the protective film. That is, it is known that the discharge voltage is lowered as the secondary electron emission coefficient of the protective film is larger (as the work function is smaller and electrons are more likely to be emitted).
JP 2002-231129 A

However, when a protective film made of MgO is used, the discharge voltage becomes high. When the discharge voltage is high, the power consumption of the PDP increases, the sputter resistance of the protective film decreases and the function as the protective film decreases, and the driver circuit for higher voltage than the conventional driver circuit for driving the PDP Therefore, there arises a problem that the cost is increased. Accordingly, there is a need for a PDP with a lower discharge voltage that has a protective film with excellent electron emission characteristics.
In addition, during discharge, cations generated by turning the discharge gas into plasma collide with the protective film, so that the protective film is required to have high sputtering resistance.

  In view of the circumstances as described above, an object of the present invention is to provide a plasma display panel, a plasma display panel manufacturing method, and a plasma display panel manufacturing apparatus having a low discharge voltage and high sputtering resistance.

  The present inventors have found that the protective film of the plasma display panel is formed of SrO or CaO which is an alkaline earth metal oxide similar to MgO as a main component. For example, when SrO is used as the material for the protective film, the discharge voltage is reduced as compared with the case of using MgO, but the sputtering resistance is lowered. On the other hand, when a mixture of SrO and CaO, which is also an alkaline earth metal oxide, is used, since CaO supplements the sputtering resistance, the discharge voltage is lowered and the high sputtering resistance is achieved. Can be maintained.

On the other hand, CaO contained in this mixture is extremely active against impurity gases such as H ₂ O, CO, and CO ₂ , and easily reacts with these to form Ca (OH) ₂ and CaCO _3. . As a result, the aging time becomes long. On the other hand, the present inventors use SrO that greatly contributes to the reduction of the discharge voltage as the main component of the protective film, and MgO that has sputtering resistance and is inert to the impurity gas. It has been found that when the concentration of MgO is 30 mol% or more and 70 mol% or less, the discharge voltage is low, the sputtering resistance is high, and the aging time can be shortened.

  Therefore, in the plasma display panel according to the present invention, the first substrate and the second substrate are disposed to face each other, and the discharge gas is sealed between the first substrate and the second substrate. A plasma display panel comprising: a first electrode provided on a surface of the first substrate facing the second substrate; and a surface of the second substrate facing the first substrate. And a protective film provided on at least one of the first electrode and the second electrode, the protective film containing SrO and MgO as main components, and the protective film The MgO concentration therein is 30 mol% or more and 70 mol% or less.

  Here, the reason why the MgO concentration is set to 30 mol% or more is that when the MgO concentration is lower than 30 mol%, the sputtering resistance of the protective film decreases. The reason why the MgO concentration is set to 70 mol% or less is that the discharge voltage increases when the MgO concentration exceeds 70 mol%.

In the present invention, specifically, the discharge gas preferably contains 10% by volume or more of Xe.
It is known that in a discharge gas used for a plasma display panel, the brightness becomes high when the concentration of Xe is high, particularly 10% by volume or more. On the other hand, it is known that the discharge voltage increases when the concentration of Xe is 10% by volume or more.

  On the other hand, according to the present invention, the protective film contains SrO and MgO as main components, and the concentration of the MgO in the protective film is 30 mol% or more and 70 mol% or less. Since Xe is 10% by volume or more, high luminance can be achieved while maintaining the discharge voltage at a low voltage.

A method for manufacturing a plasma display panel according to the present invention is a method for manufacturing a plasma display panel having a first substrate provided with a first electrode and a second substrate provided with a second electrode, wherein the protective film comprises: A protective film that contains SrO and MgO as main components and the MgO concentration in the protective film is 30 mol% or more and 70 mol% or less on at least one of the first electrode and the second electrode. After the film forming step and the protective film forming step, a sealing step of bonding the first substrate and the second substrate so that a discharge gas is sealed between the first substrate and the second substrate. And the process from the protective film forming step to the sealing step is performed in a vacuum atmosphere or an atmosphere having a dew point of −60 ° C. or lower.
According to the present invention, since the protective film forming process to the sealing process are performed in a vacuum atmosphere or an atmosphere having a dew point of −60 ° C. or less, it is possible to effectively prevent moisture absorption of the protective film. . Thereby, the lifetime of a plasma display panel can be extended.

  An apparatus for manufacturing a plasma display panel according to the present invention contains SrO and MgO as main components on at least one of a first electrode provided on a first substrate and a second electrode provided on a second substrate. A protective film forming part for forming a protective film having a MgO concentration of 30 mol% or more and 70 mol% or less in the protective film; and connected between the protective film forming part and between the first substrate and the second substrate The sealing part for bonding the first substrate and the second substrate so that the discharge gas is sealed in, and the protective film forming part and the sealing part are in a vacuum atmosphere or a dry atmosphere with a dew point of −60 ° C. or lower. As described above, it is characterized by comprising adjusting means for adjusting the atmosphere of the protective film forming part and the sealing part.

  According to the present invention, since the formation from the protective film to the sealing can be performed in a vacuum atmosphere or an atmosphere having a dew point of −60 ° C. or lower, the inside of the plasma display panel can be maintained in a low humidity state. . Thereby, the lifetime of a plasma display panel can be extended.

  According to the present invention, the protective film contains SrO and MgO as main components, and the concentration of the MgO in the protective film is 30 mol% or more and 70 mol% or less. It has high sputter resistance and can shorten the aging time. In addition, since the Xe of the discharge gas is set to 10% by volume or more, high luminance can be achieved while maintaining the discharge voltage at a low voltage. Furthermore, since the protective film forming process to the sealing process are performed in a vacuum atmosphere or an atmosphere having a dew point of −60 ° C. or lower, it is possible to effectively prevent moisture absorption of the protective film. Long life can be achieved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed in order to make each member a recognizable size.
(Plasma display panel)
FIG. 1 is an exploded perspective view of a three-electrode AC type plasma display panel.
In a plasma display panel (PDP) 100, a back substrate (first substrate) 1 and a front substrate (second substrate) 2 are disposed to face each other, and a plurality of discharge chambers 16 are provided between the back substrate 1 and the front substrate 2. It is the composition which has.

  On the inner surface of the back substrate 1 (the surface facing the front substrate 2), a plurality of address electrodes (first electrodes) 11 are arranged in stripes at predetermined intervals. A dielectric layer 19 is provided on the surface of the plurality of address electrodes 11. The dielectric layer 19 is provided on the entire surface of the back substrate 1 including the address electrodes 11, and the surface of the dielectric layer 19 is flat.

  Partitions (ribs) 15 are provided in the region between adjacent address electrodes 11 on the surface of the dielectric layer 19 along the extending direction of the address electrodes 11. A phosphor 17 that emits red, green, or blue fluorescence is disposed between the adjacent barrier ribs 15 so as to cover the upper surface of the dielectric layer 19 and the side surfaces of the barrier ribs 15, respectively.

  On the other hand, on the inner surface of the front substrate 2 (the surface facing the rear substrate 1), the scanning electrodes 12a and the sustain electrodes 12b constituting the display electrode (second electrode) 12 are alternately arranged in stripes at predetermined intervals. ing. The display electrode 12 is made of a transparent conductive material such as ITO, and extends in a direction orthogonal to the address electrode 11. The intersection of the address electrode 11 and the display electrode 12 is a pixel of the PDP 100. At the intersection, the distance (discharge gap) between the address electrode 11 and the display electrode 12 is about 80 μm.

  A dielectric layer 13 is formed on the display electrode 12 so as to cover the display electrode 12 and the inner surface of the front substrate 2. A protective film 14 is formed on the dielectric layer 13 so as to cover the dielectric layer 13. The protective film 14 protects the dielectric layer 13 from cations generated by the plasma of the discharge gas. The protective film 14 has SrO that greatly contributes to the reduction of the discharge voltage, and has sputtering resistance and is resistant to impurity gas. Contains active MgO. The concentration of MgO in the protective film 14 is 30% to 70 mol%. The range of the MgO concentration will be described in detail in [Example 1] to [Example 3]. The thickness of the protective film 14 is about 8000 mm.

  The rear substrate 1 and the front substrate 2 thus configured are bonded together by, for example, a sealing material, and a discharge chamber 16 is formed between adjacent barrier ribs 15. Inside the discharge chamber 16, a discharge gas such as a mixed gas of Ne and Xe is sealed at a pressure of about 400 Torr. The discharge gas contains 10% by volume or more, for example, about 12% by volume of Xe gas.

  When lighting the pixel, a DC voltage is applied between the address electrode 11 and the scan electrode 12a to generate a counter discharge, and an AC voltage is further applied between the scan electrode 12a and the sustain electrode 12b. Generate a discharge. The discharge gas sealed in the discharge chamber 16 is turned into plasma by discharge, and vacuum ultraviolet rays are emitted. The phosphor 17 is excited by the ultraviolet rays, and visible light is emitted from the front substrate 2. The discharge voltage at this time is called the first cell lighting voltage.

(Plasma display panel manufacturing equipment)
Next, the PDP manufacturing apparatus according to the present embodiment will be described with reference to FIG.
As shown in the figure, a PDP manufacturing apparatus 30 introduces a front substrate 2 and a rear substrate 1 and manufactures a PDP 100 by vacuum processing, and includes a front substrate load chamber 31, a vapor deposition chamber (protective film forming section). 32, a cooling chamber 33, a back substrate loading chamber 34, a degassing chamber 35, a transfer chamber 36, an alignment / sealing chamber (sealing portion) 37, and an unloading chamber 38. Each of these chambers is connected to a vacuum exhaust mechanism (control means) 48 such as a rotary pump or a turbo molecular pump.

The front substrate load chamber 31 is a space for carrying the front substrate 2 and is connected to the vapor deposition chamber 32. A transport mechanism (not shown) for transporting the front substrate 2 carried into the front substrate load chamber 31 to the vapor deposition chamber 32 is provided.
The vapor deposition chamber 32 is a space for depositing the protective film 14 on the front substrate 2 and is connected to the front substrate load chamber 31 and the cooling chamber 33 described above. In the vapor deposition chamber 32, a heating mechanism 41 for heating the front substrate 2, an evaporating material 42 mainly composed of SrO and MgO, and an electron beam gun 43 for irradiating the evaporating material 42 with an electron beam are arranged. ing. The evaporation material 42 can be evaporated by irradiating the evaporation material 42 with an electron beam. The vapor deposition chamber 32 is provided with an oxygen gas introduction mechanism (not shown) for introducing oxygen gas into the vapor deposition chamber 32 during vapor deposition.

  The cooling chamber 33 is a space for cooling the front substrate 2 heated in the vapor deposition chamber 32, and is connected to the vapor deposition chamber 32 and the transfer chamber 36 described above. In the cooling chamber 33, a support base 44 that supports the front substrate 2 and a cooling mechanism 45 provided in the support base 44 are provided. The cooling mechanism 45 is provided with a control unit (not shown) so that the substrate temperature of the front substrate 2 supported by the support base 44 can be cooled and controlled to a predetermined temperature.

The rear substrate load chamber 34 is a space for carrying the rear substrate 1 and is connected to the degas chamber 35. A transport mechanism (not shown) for transporting the back substrate 1 carried into the back substrate load chamber 34 to the degas chamber 35 is provided.
The degassing chamber 35 is a space for heating the back substrate 1 to remove gas (such as water vapor) adsorbed on the back substrate 1, and is connected to the back substrate loading chamber 34 and the transfer chamber 36 described above. A heating mechanism 46 for heating the back substrate 1 is provided in the degas chamber 35.

  The transfer chamber 36 is connected to the cooling chamber 33 and the degas chamber 35 described above, and is a space where the front substrate 2 from the cooling chamber 33 and the rear substrate 1 from the degas chamber 35 merge. The transfer chamber 36 is also connected to an alignment / sealing chamber 37 and is a space for transferring the joined front substrate 2 and rear substrate 1 to the alignment / sealing chamber 37. The transfer chamber 36 is also connected to an unload chamber 38 and is a space for transferring the PDP 100 from the alignment / sealing chamber 37 to the unload chamber 38. For this reason, the transfer chamber 36 is provided with a transfer robot (not shown) for transferring the front substrate 2, the rear substrate 1 and the PDP.

  The alignment / sealing chamber 37 positions the front substrate 2 and the rear substrate 1, seals both substrates using a sealing material, and encloses a discharge gas between the front substrate 2 and the rear substrate 1. This is a space for completing the PDP 100. The alignment / sealing chamber 37 is connected to the transfer chamber 36 described above.

The alignment / sealing chamber 37 is provided with a positioning mechanism (not shown) for positioning the front substrate 2 and the rear substrate 1 and a discharge gas supply unit (not shown) for supplying a discharge gas. The alignment / sealing chamber 37 is provided with a discharge gas purifier 47 for purifying the discharge gas diffused in the chamber, so that the discharge gas purified by the discharge gas purifier 47 can be reused. Yes.
The unload chamber 38 is a space for taking out the PDP 100 completed in the alignment / sealing chamber 37 to the outside, and is connected to the transfer chamber 36 described above.

(Plasma display panel manufacturing method)
Next, a method for manufacturing the PDP 100 according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing a flow of manufacturing the PDP 100 according to the present embodiment. In this embodiment, the front substrate 2 and the rear substrate 1 are formed separately, and the PDP 100 is manufactured by a procedure in which both substrates are bonded.

A procedure for forming the front substrate 2 will be described.
First, the display electrode 12 and the dielectric layer 13 are formed on the front substrate 2 (ST11). In this state, the front substrate 2 is carried into the front substrate load chamber 31 of the PDP manufacturing apparatus 30. When the front substrate 2 is carried in, the transport mechanism in the front substrate load chamber 31 transports the front substrate 2 to the vapor deposition chamber 32.

In the vapor deposition chamber 32, the protective film 14 is formed (ST12: protective film forming step).
First, the inside of the vapor deposition chamber 32 is evacuated by an evacuation mechanism. When the inside of the vapor deposition chamber 32 is evacuated, oxygen gas is supplied into the vapor deposition chamber 32 by an oxygen gas supply mechanism, and the partial pressure of the oxygen gas is controlled to be about 3.0 × 10 ⁻² Pa. At the same time, the substrate temperature of the front substrate 2 is adjusted to about 250 ° C.

  When the evaporation material 42 is evaporated by irradiating the electron beam from the electron beam gun 43 toward the evaporation material 42 while adjusting the partial pressure of the oxygen gas and the substrate temperature of the front substrate 2, the evaporated evaporation material 42 is evaporated. It circulates in the chamber 32 as a vapor flow and deposits on the front substrate 2 at a film formation rate of about 40 Å / s. The deposit of the evaporation material 42 becomes the protective film 14. In addition, the density | concentration of MgO in the evaporation material 42 is 30% mol-70 mol%.

After forming the protective film 14, the front substrate 2 is transferred onto the support base 44 of the cooling chamber 33. In the cooling chamber 33, the front substrate 2 heated at the time of vapor deposition is cooled to a predetermined temperature by the cooling mechanism 45 in a vacuum atmosphere (ST13).
In this way, the front substrate 2 is formed.

Next, a procedure for forming the back substrate 1 will be described.
First, the address electrode 11, the dielectric layer 19, the partition wall 15, and the phosphor 17 are formed on the inner surface of the back substrate 1 (ST21), and a sealing material (not shown) is further formed (ST22). In this state, it is carried into the rear substrate load chamber 34 of the PDP manufacturing apparatus 30. When the back substrate 1 is carried in, the transfer mechanism in the back substrate load chamber 34 transfers the back substrate to the degas chamber 35. In the degassing chamber 35, the back substrate 1 is heated in vacuum to perform a degassing process on the sealing material formed on the inner surface of the back substrate 1 (ST23).

After the degassing process, the rear substrate 1 is transferred to the transfer chamber 36 and transferred from the transfer chamber 36 to the alignment / sealing chamber 37.
In the alignment / sealing chamber 37, positioning is performed for bonding the front substrate 2 and the rear substrate 1 under a vacuum atmosphere (ST31). When the positioning is completed, a discharge gas is introduced into the alignment / sealing chamber 37 (ST32). When the discharge gas is introduced, the sealing material is heated to bond the front substrate 2 and the rear substrate 1 together (ST33). When the bonding is completed, the sealing material is cured, and the front substrate 2 and the rear substrate 1 are sealed with the discharge gas sealed between the front substrate 2 and the rear substrate 1 (ST34). Thus, the sealing process is performed in the alignment / sealing chamber 37 to obtain the PDP 100. After the sealing step, the discharge gas is taken in by the discharge gas purifier 47 and made reusable.
Thereafter, the PDP 100 is transferred to the unload chamber 38 via the transfer chamber 36 and taken out from the unload chamber 38.

According to the present embodiment, the protective film 14 formed on the PDP 100 contains SrO and MgO as main components, and the concentration of the MgO in the protective film is 30 mol% or more and 70 mol% or less. It is possible to obtain a PDP 100 in which the voltage is low, the sputtering resistance is high, and the aging time can be shortened.
In this embodiment, since the protective film forming process to the sealing process are performed in a vacuum atmosphere, it is possible to effectively prevent moisture absorption of the protective film 14. Thereby, the lifetime of PDP100 can be achieved.

The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention.
In the embodiment described above, the process from the protective film forming process to the sealing process is described as being performed in a vacuum atmosphere, but the present invention is not limited to this. For example, the process from the protective film forming step to the sealing step may be performed in a dry atmosphere with a dew point of −60 ° C. or lower. In this case, CDA (Clean Dry Air) is supplied into the PDP manufacturing apparatus 30 (particularly, in the vapor deposition chamber 32, the cooling chamber 33, the degas chamber 35, the transfer chamber 36, and the alignment / sealing chamber 37). It is preferable to have a CDA supply mechanism and a CDA discharge mechanism that discharges CDA from the PDP manufacturing apparatus 30. By supplying CDA into the PDP manufacturing apparatus 30, the inside of the PDP manufacturing apparatus 30 can be easily made into a dry atmosphere having a dew point of −60 ° C. or less. Even in a dry atmosphere with a dew point of −60 ° C. or lower, it is possible to sufficiently prevent the protective film 14 from absorbing moisture.
Moreover, in the said embodiment, although it was the structure which forms the protective film 14 only in the back substrate 1, it is not restricted to this. For example, it does not matter if the protective film 14 is formed on both the back substrate 1 and the front substrate 2.

Next, an example of the relationship between the composition of the protective film and the discharge voltage will be described.
FIG. 4 shows the relationship between the MgO concentration in the protective film containing SrO and MgO, the first cell turn-on voltage (unit: V) corresponding to the MgO concentration, and the first cell turn-off voltage. . The “first cell extinguishing voltage” is a voltage when the cell goes from the on state to the off state. In the graph of FIG. 4, the vertical axis represents the magnitude of the discharge voltage (unit: V), and the horizontal axis represents the MgO concentration (unit: mol%).

  The value when the MgO concentration was changed by 10 mol% from 0 mol% to 100 mol% was measured. This protective film is made of SrO and MgO, and the sum of the MgO concentration and the SrO concentration is 100 mol%. For example, if the MgO concentration is 40 mol%, the SrO concentration is 60 mol%.

  Here, the cell is a panel having substantially the same conditions as those of the PDP 100 described above. The discharge gap of the cell is 80 μm, the discharge gas is a mixed gas of Ne and Xe, the concentration of Xe in the discharge gas is 12% by volume, the pressure of the discharge gas is 400 Torr, and the frequency is 40 kHz. It was supposed to be.

As shown in FIG. 4, when the MgO concentration in the protective film is 100 mol% (SrO concentration is 0 mol%), that is, in the conventional protective film made of MgO, the first cell lighting voltage is 220 V, The one-cell extinguishing voltage was 155V.
On the other hand, when the MgO concentration in the protective film was 90 mol% (SrO concentration was 10 mol%), the first cell lighting voltage was 215 V and the first cell lighting voltage was 150 V. Further, when the MgO concentration in the protective film was 80 mol% (SrO concentration was 20 mol%), the first cell lighting voltage was 206V and the first cell extinguishing voltage was 149V. By decreasing the MgO concentration in the protective film and increasing the SrO concentration, the first cell turn-on voltage and the first cell turn-off voltage are gradually lowered.

  When the MgO concentration in the protective film was 70 mol% (SrO concentration was 30 mol%), the first cell turn-on voltage was 190 V and the first cell turn-off voltage was 135 V. Further, when the MgO concentration in the protective film was 60 mol% (SrO concentration was 40 mol%), the first cell lighting voltage was 175 V and the first cell turn-off voltage was 127 V. Thus, when the MgO concentration in the protective film is between 50 mol% and 80 mol%, the first cell turn-on voltage and the first cell turn-off voltage are drastically lowered by decreasing the MgO concentration.

When the MgO concentration in the protective film was 50 mol% (SrO concentration was 50 mol%), the first cell lighting voltage was 168V, and the first cell turn-off voltage was 120V. When the MgO concentration in the protective film was 40 mol% (SrO concentration was 60 mol%), the first cell lighting voltage was 165 V and the first cell extinguishing voltage was 118 V. Hereinafter, the first cell turn-on voltage and the first cell turn-off voltage gradually decrease until the MgO concentration reaches 0 mol% (the first cell turn-on voltage is 160 V and the first cell turn-off voltage is 110 V).
Therefore, from the viewpoint of lowering the discharge voltage, it can be said that the MgO concentration in the protective film is preferably 70 mol% or less at which the discharge voltage is greatly reduced.

Next, examples regarding the relationship between the composition of the protective film and the sputtering resistance will be described.
FIG. 5 shows the MgO concentration in the protective film containing SrO and MgO, and the etching rate corresponding to the MgO concentration. In this embodiment, a method is used in which a radio frequency (RF) is applied to argon (Ar) atoms to generate plasma and collide with a protective film. The Ar introduction pressure is about 1.0 Pa, the radio frequency (RF) power density is 0.2 W / cm ² , and the sputtering time is 72 hours.

  The etching rate is a relative value with a value of 1 when the MgO concentration in the protective film is 100%, that is, when the protective film is composed only of MgO. The lower the etching rate, the higher the sputtering resistance. In FIG. 5, the vertical axis represents the magnitude (relative value) of the etching rate, and the horizontal axis represents the MgO concentration (unit: mol%).

  Here, the value is shown when the MgO concentration is changed by 10 mol% from 0 mol% to 100 mol%. This protective film is made of SrO and MgO, and the sum of the MgO concentration and the SrO concentration is 100 mol%. For example, if the MgO concentration is 40 mol%, the SrO concentration is 60 mol%.

  As shown in FIG. 5, when the etching rate when the MgO concentration in the protective film is 100 mol% (SrO concentration is 0 mol%) is 1, the etching rate is 1.05 when the MgO concentration is 90 mol%, MgO The MgO concentration is 1.1 when the concentration is 80 mol%, 1.15 when the MgO concentration is 70 mol%, 1.2 when the MgO concentration is 60 mol%, and 1.25 when the MgO concentration is 50 mol%. Increases from 100 mol% to 50 mol% with the same increase.

  The etching rate is 1.4 when the MgO concentration is 40 mol%, and 1.7 when the MgO concentration is 30 mol%, and the increase is increased. Further, when the MgO concentration is lower than 30 mol%, the etching rate is 2.2 when the MgO concentration is 20 mol%, 2.7 when the MgO concentration is 10 mol%, and 3. 3 when the MgO concentration is 0 mol%. 4 and the amount of increase is further expanding.

  Thus, as the MgO concentration in the protective film decreases, the etching rate increases (sputtering resistance decreases). Therefore, from the viewpoint of sputtering resistance, the MgO concentration in the protective film is preferably at least 30 mol% or more, more preferably 50 mol% or more, in a range where the increase in the etching rate does not increase.

Next, an example of the relationship between the composition of the protective film, the aging time, and the first cell lighting voltage will be described.
FIG. 6 shows the aging time and the first cell lighting voltage when the MgO concentration in the protective film containing SrO and MgO is (1) 70 mol%, (2) 50 mol%, and (3) 30 mol%, respectively. It is the table | surface which showed the relationship. As a comparative example, (4) the above relationship for a protective film made of a mixture of SrO and CaO (CaO concentration is 50 mol%) is also shown. In the graph of FIG. 6, the vertical axis represents the first cell lighting voltage (unit: V), and the horizontal axis represents aging time (unit: min).

  Here, the cell is a panel having substantially the same conditions as those of the PDP 100 described above. The discharge gap of the cell is 80 μm, the discharge gas is a mixed gas of Ne and Xe, the concentration of Xe in the discharge gas is 12% by volume, the pressure of the discharge gas is 400 Torr, and the frequency is 40 kHz. It was supposed to be.

  As shown in FIG. 6, when the MgO concentration is 70 mol% (in the case of (1)), the first cell lighting voltage is gradually decreased from 0 min to 50 min, and is stabilized from about 50 min. . The first cell lighting voltage at the time of stability is about 190V.

  When the MgO concentration is 50 mol% (in the case of (2)), the first cell lighting voltage gradually decreases when the aging time is between 0 min and 40 min, and the first cell lighting voltage is stabilized after 40 min has passed. Yes. The first cell lighting voltage when stabilized is about 166V to 168V. Compared with the case (1), the first cell lighting voltage at the time of stabilization is low, and the aging time is short.

  When the MgO concentration is 30 mol% (in the case of (3)), the first cell lighting voltage rapidly decreases when the aging time is between 0 min and 20 min. Stabilize. The first cell lighting voltage at the time of stability is about 163V to 166V. Compared to the cases (1) and (2), the stable first cell lighting voltage is low. Also, the aging time is shortened.

As for the comparative example (in the case of (4)), the first cell lighting voltage gradually decreases from 0 min to 100 min, and the first cell lighting voltage stabilizes after about 100 min. The first cell lighting voltage at the time of stability is about 155V. Compared with (1) to (3), the aging time until the first cell lighting voltage is stabilized is longer.
From these facts, it is understood that the aging time can be shortened by containing 30% to 70% of MgO in the protective film.

Sectional drawing which shows the structure of PDP which concerns on embodiment of this invention. The top view which shows the structure of the PDP manufacturing apparatus which concerns on this embodiment. The flowchart which shows the manufacturing process of PDP which concerns on this embodiment. The graph which shows the relationship between MgO density | concentration and discharge voltage. The graph which shows the relationship between MgO density | concentration and sputtering speed. The graph which shows the relationship between MgO density | concentration, a 1st cell lighting voltage, and aging time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Back substrate 2 ... Front substrate 11 ... Address electrode 12 ... Display electrode 12a ... Scan electrode 12b ... Sustain electrode 13 ... Dielectric layer 14 ... Protective film 16 ... Discharge chamber 30 ... PDP manufacturing apparatus 32 ... Deposition chamber 37 ... Alignment Sealing chamber 100 ... PDP

Claims (4)

A plasma display panel in which a first substrate and a second substrate are arranged to face each other, and are bonded so that a discharge gas is sealed between the first substrate and the second substrate,
A first electrode provided on a surface of the first substrate facing the second substrate;
A second electrode provided on a surface of the second substrate facing the first substrate;
A protective film provided on at least one of the first electrode and the second electrode;
The protective film contains SrO and MgO as main components,
The plasma display panel, wherein the MgO concentration in the protective film is 30 mol% or more and 70 mol% or less. The plasma display panel according to claim 1, wherein the discharge gas contains 10% by volume or more of Xe. A method of manufacturing a plasma display panel having a first substrate provided with a first electrode and a second substrate provided with a second electrode,
The protective film contains SrO and MgO as main components, and the protective film in which the concentration of MgO in the protective film is 30 mol% or more and 70 mol% or less is at least one of the first electrode and the second electrode A protective film forming step to be formed on,
A sealing step of bonding the first substrate and the second substrate so that a discharge gas is sealed between the first substrate and the second substrate after the protective film forming step;
The process from the protective film forming step to the sealing step is performed in a vacuum atmosphere or an atmosphere having a dew point of −60 ° C. or lower. At least one of the first electrode provided on the first substrate and the second electrode provided on the second substrate contains SrO and MgO as main components, and the concentration of MgO in the protective film is 30 mol%. A protective film forming portion for forming a protective film of 70 mol% or less;
A sealing unit that is connected to the protective film forming unit and bonds the first substrate and the second substrate so that a discharge gas is sealed between the first substrate and the second substrate;
Adjusting means for adjusting the atmosphere of the protective film forming part and the sealing part so that the protective film forming part and the sealing part are in a vacuum atmosphere or a dry atmosphere having a dew point of −60 ° C. or lower. A plasma display panel manufacturing apparatus.

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