JP2002110048A - Protective film for FPD and FPD using the same - Google Patents

Abstract

(57) [Problem] To prevent a decrease in adhesion and matching of a protective film with a substrate (dielectric layer) and a decrease in electric insulation of the protective film. In addition, the fluoride layer prevents MgO and the like in the film body from reacting with CO ₂ gas and H ₂ O gas in the atmosphere, so that MgCO ₃ and Mg which are harmful to FPD such as MgO.
(OH) Prevents deterioration to ₂ etc. A film main body, which is an aggregate of a plurality of columnar crystallites a standing upright on a surface of a substrate, is formed, and a fluoride layer is formed on a peripheral side surface and a top surface of the columnar crystallites. It is formed. The fluoride layer 15 is composed of MO _X F _Y (M is Mg, Ca, Sr, Ba, an alkaline earth composite metal or a rare earth metal, or a composite metal of an alkaline earth metal and a rare earth metal, and 0 ≦ X <2,0 <Y ≦ 4), and the fluoride layer 15 is obtained by a reaction between a gaseous fluorinating agent and MgO or the like. The fluorinating agent is fluorine gas,
There is hydrogen fluoride gas, BF ₃ , SbF ₅ or SF ₄ .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a PDP (Plasma D
isplay Panel: plasma display panel), PAL
The present invention relates to a protective film for an FPD (Flat Panel Display) such as C (Plasma Addressed Liquid Crystal display) and an FPD using the same.

[0002]

2. Description of the Related Art Since a protective film of a PDP is in direct contact with a discharge space, it is a key material that plays the most important role in discharge characteristics, and has a higher secondary electron emission ability, sputter resistance and light transmission. An MgO film having excellent properties and insulating properties is used. However, if this MgO film is exposed to the air in the middle of the process, it easily reacts with CO ₂ or H ₂ O and changes its quality. It is known that a long-time degassing exhaust treatment under heating is necessary [for example, edited by Sato; latest plasma display manufacturing technology (Press Journal Co., Ltd.): p.
118-123 and p.291-295 (1997)]. According to this, H ₂
Impurity gas such as O, H ₂ , O ₂ , CO, CO ₂ , N ₂ is PD
It is said that the discharge characteristics of P and the constituent materials in the panel are adversely affected, and in particular, contamination by CO ₂ deteriorates the panel characteristics to an irreparable degree.

For this reason, in order to prevent deterioration of MgO,
It has been proposed to coat the MgO surface with another material having low moisture permeability (Japanese Patent Application Laid-Open No. H10-149767).
No., WTLee et al; "LaF ₃ coated MgO protecting laye
r in AC-Plasma Display Panels ", IDW'99, pp. 72-75.) In the above-mentioned Japanese Patent Application Laid-Open No. H10-149767, after forming a protective film, a temporary protective film having low moisture permeability is formed on the protective film. Is formed, and then the temporary protective film is removed. In this method, during the production of the PDP, the surface of the protective film is protected by the temporary protective film. No altered layer is formed, and as a result,
A protective film with good discharge characteristics can be obtained,
The thermal decomposition treatment of the altered layer of the protective film becomes unnecessary. Also WTLe
In the above-mentioned document by e et al., L with low moisture permeability is formed on the MgO protective film.
It has been proposed that by coating with aF ₃ , deterioration of the MgO protective film can be suppressed and higher secondary electron emission characteristics and lower discharge characteristics can be realized.

[0004]

However, in the method of manufacturing a PDP described in the above-mentioned conventional Japanese Patent Application Laid-Open No. 10-149767 and the document of WTLee et al., A temporary protective film and a protective film are formed when forming the temporary protective film. Is difficult to match, and the temporary protective film may be cracked or the temporary protective film may be peeled off, and the effect of the temporary protective film to prevent the deterioration of the protective film is insufficient. In order to improve this, a method of laminating a temporary protective film on the protective film thickly can be considered. However, this method has a problem that a large amount of impurities (decomposed products of the temporary protective film) are generated when the temporary protective film is removed. there were. Further, in the above-mentioned WTLee et al.
LaF ₃ of 0 nm is laminated, and in such a two-layer structure, if LaF _{3 of} the upper layer film is removed by sputtering, the discharge voltage changes drastically, so that a sufficient lifetime cannot be obtained. there were.

An object of the present invention is to provide a protective film for an FPD that can prevent a decrease in adhesion and matching with a substrate (dielectric layer) and a decrease in electrical insulation. Another object of the present invention is to prevent or suppress the reaction of MgO or the like in the film main body with CO ₂ gas or H ₂ O gas in the atmosphere during the FPD manufacturing process by the fluoride layer.
An object of the present invention is to provide a protective film for FPD that can prevent or suppress the transformation of MgO or the like into MgCO ₃ or Mg (OH) ₂ harmful to the FPD, that is, improve the environmental resistance of the film body. Still another object of the present invention is to provide an FPD using a protective film, which can significantly reduce the number of manufacturing steps.

[0006]

The invention according to claim 1 is
As shown in FIGS. 1 and 2, MgO,
CaO, SrO, BaO, alkaline earth complex oxide
Or rare earth oxides or alkaline earth oxides and rare earths
Film body formed by any of oxide composite oxides
14 and a fluoride layer formed on the surface of the film body 14
15 and the film main body 14 stands closely on the surface of the substrate 13.
An aggregate of a plurality of columnar crystallites 14a provided,
Is formed on the peripheral side surface and top surface of the plurality of columnar crystallites 14a.
Are the protective films for FPD formed respectively. This bill
In the protective film for FPD described in the item 1, the film main body 14 is composed.
The plurality of columnar crystallites 14a to be formed
5 to produce the FPD 10 (see FIG. 2).
During the fabrication process, the film body 14 and the fluoride layer 15
Even if the protective film 22 is exposed to the air for a long time,
4 in the atmosphere is CO _TwoGas or H_TwoO gas and most
no response. As a result, MgO or the like in the film body 14a becomes F
MgCO that may impair the function of PD10_ThreeAnd Mg
(OH)_TwoIt hardly changes in quality.

[0007] The substrate 13 of the protective film 14
Since the film main body 14a having substantially the same thermal expansion coefficient as 3 is bonded, the protective film 14 does not peel off from the substrate 13 due to a thermal cycle, and the adhesion and the consistency of the protective film 14 to the substrate 13 become extremely good. The fluoride layer 14b is made of MO _X F
_Y (M is Mg, Ca, Sr, Ba, an alkaline earth composite metal, a rare earth metal, or a composite metal of an alkaline earth metal and a rare earth metal, and 0 ≦ X <2, 0 <Y ≦ 4.) It is preferred that Further, the fluoride layer 14b is made of a gaseous fluorinating agent and MgO, CaO, SrO, BaO,
It is preferably obtained by a reaction with an alkaline earth composite oxide or a rare earth oxide, or a composite oxide of an alkaline earth oxide and a rare earth oxide. Fluorine gas, hydrogen fluoride gas, B
It is preferable to use any one of F ₃ , SbF _{5 and} SF ₄ , particularly a fluorine gas or a hydrogen fluoride gas. Further, the ratio y / of the diameter x of the columnar crystallite 14a and the thickness y of the fluoride layer 15
x is preferably 0.001 or more and 0.2 or less.
Here, in this specification, the “diameter of columnar crystallites”
When the cross section of the columnar crystallite 14a is circular as shown in FIG. 3, its diameter x is changed to the columnar crystallite 1 as shown in FIG.
When the cross section of 4a is a triangle, it means the length x from the vertex to the opposite side. Further, the “columnar shape” is not limited to the above-described circular shape or substantially triangular shape, but includes a rectangular shape such as a quadrangle, a pentagon, and a hexagon, and an ellipse.

The invention according to claim 6 is the invention according to claims 1 to 5
An FPD characterized by using any one of the protective films described above.
It is. In the FPD according to the sixth aspect, the FPD
Since the number of manufacturing steps can be significantly reduced, an FPD can be manufactured at low cost.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of the present invention will be described with reference to the drawings. The FPD of the present invention is PD
P, PALC and the like. In this embodiment, the PD
P will be described. As shown in FIG. 1 and FIG.
The PDP 10 has a front glass substrate 13 through a partition wall 12 formed on the rear glass substrate 11 at a predetermined interval.
It is constituted by putting on. A film main body 14 is formed on a surface of the front glass substrate 13 facing the rear glass substrate 11 via a display electrode 16 and a transparent dielectric layer 17, and a fluoride layer 15 is formed on the surface of the film main body 14. It is formed. As shown in the enlarged view of the figure, the film main body 14 is an aggregate of a plurality of columnar crystallites 14a closely standing on the surface of the front glass substrate 13, and the fluoride layer 15 is composed of the plurality of columnar crystallites 14a. Are formed on the peripheral side surface and the top surface, respectively. Back glass substrate 11, front glass substrate 13, partition wall 1
2 form a large number of discharge cells 18, and address electrodes 19 are formed on the rear glass substrate 11 so as to be located in the discharge cells 18 and face the display electrodes 16. In the discharge cell 18, a phosphor layer 21 is formed from the side surface of the partition 12 to the upper surface of the rear glass substrate 11. Further, a discharge gas (not shown) is injected into the discharge cells 18.

The fluoride layer 15 is composed of MO _X F _Y (M is M
g, Ca, Sr, Ba, an alkaline earth composite metal or a rare earth metal, or a composite metal of an alkaline earth metal and a rare earth metal, where 0 ≦ X <2, 0 <Y ≦ 4. ), For example, MF ₂ layer, MO _0.5 F layer, MO _0.25 F _1.5 layer,
There are _four layers of MF, _two layers of MOF, _three layers of MF, layers of MOF, _2.66 layers of MF, _0.66 layers of MOF and the like. The fluoride layer 15 is made of a material such as MgO, CaO, SrO, BaO, an alkaline-earth composite oxide or a rare-earth oxide, or a composite oxide of an alkaline-earth oxide and a rare-earth oxide, which forms the film main body 14. The gaseous fluorinating agent can be obtained by reaction with a gaseous fluorinating agent. From the viewpoints of high reactivity and versatility, fluorine gas, hydrogen fluoride gas, BF ₃ , SbF ₅
Alternatively, it is preferable to use any one of SF ₄ , particularly fluorine gas or hydrogen fluoride gas.

As shown in FIGS. 3 and 4, the ratio y / to the diameter x of the columnar crystallites 14a and the thickness y of the fluoride layer 15 is determined.
x is determined by the balance between the improvement of the reaction inhibition with CO ₂ gas such as MgO or H ₂ O gas and the reaction time between MgO or the like and the gaseous fluorinating agent, and is 0.001 or more and 0.2 or less. Is more preferable, and a more preferable value of this ratio is 0.005.
It is 0.1 or less. The ratio y / x of the diameter x of the columnar crystallites 14a to the thickness y of the fluoride layer 15 is 0.001 or more.
If the ratio is less than 0.001, the fluoride layer 15 may not be able to sufficiently protect the film main body 14, which is an aggregate of a plurality of columnar crystallites 14a, when the ratio is less than 0.001.
If the ratio exceeds the above range, the reaction time between the MgO or the like and the gaseous fluorinating agent will be prolonged, resulting in poor workability.

When the film body 14 is formed using a vacuum process, for example, an electron beam evaporation method, a sputtering method,
When the film main body 14 is formed on the surface of the glass substrate 13 by an ion plating method or the like, a plurality of columnar crystallites 14a are closely erected on the surface of the substrate 13 to form an aggregate of the plurality of columnar crystallites 14a. It is known that the membrane body 14 is formed (for example, H. Seehase; "Plasma display pa
nel MgO thin film properties and their modificatio
n by low energy ion bombardment ", Display, [1], pp.21
-34 (1985); Masayuki Kamiya, "Cathode materials for color plasma displays", OplusE, [2], pp. 90-96 (1996)). For this reason, it is necessary to use a vacuum process for the protective film of the PDP having the above-described configuration, and an example of a method of manufacturing a protective film for an FPD using a vapor deposition method and a sputtering method will be described below.

[1] Formation of Film Main Body by Vapor Deposition First, as shown in FIG. 1, an electrode paste such as Ag or Au serving as a display electrode 16 is provided on a surface of a front glass substrate 13 at a predetermined interval by a screen printing method. After coating, drying and baking, a transparent glass paste to be the transparent dielectric layer 17 is applied to the entire surface of the front glass substrate 13 by a screen printing method and dried. The front glass substrate 13 is placed in the atmosphere for 100 to 200
After drying at 10 ° C. for 10 to 60 minutes,
It is baked while being kept at 00 to 600 ° C. for 10 to 60 minutes.

Next, MgO, Ca having a purity of 99.5% or more is used.
A sintered pellet of any of O, SrO, BaO, an alkaline-earth composite oxide or a rare-earth oxide, or a composite oxide of an alkaline-earth oxide and a rare-earth oxide is prepared by an evaporation method such as electron beam evaporation. The film body 14 is formed by vapor deposition so as to cover the surface of the transparent dielectric layer 17 of the glass substrate 13, which is an aggregate of a plurality of columnar crystallites 14 a which are closely erected. The film forming conditions of the film main body 14 are as follows.
30 kV, deposition pressure 0.1 × 10 ^-2 to 10 × 10 ^-2 P
a, The deposition distance is preferably in the range of 100 to 1000 mm.

Further, the front glass substrate 13 is placed in a gaseous fluorinating agent atmosphere (at a temperature of 10 to 100 ° C.) for 0.1 to 12 hours.
By holding for 0 minute, the peripheral side surface and the top surface of the plurality of columnar crystallites 14a constituting the film main body 14 are modified, and the fluoride layer 15 is formed on the peripheral side surface and the top surface of the plurality of columnar crystallites 14a. As the gaseous fluorinating agent, it is preferable to use any one of fluorine gas, hydrogen fluoride gas, BF ₃ , SbF ₅ or SF ₄ , particularly fluorine gas or hydrogen fluoride gas. Is preferably 1 to 76
0 Torr, more preferably in the range of 10 to 300 Torr. The pressure of the gaseous fluorinating agent is 1 to 76
The reason for limiting the range to 0 Torr is to facilitate control of the reaction progress, that is, the thickness of the fluoride layer.

[2] Formation of Film Main Body by Sputtering Method First, after preparing a glass substrate with electrodes in the same manner as in the above [1], a 5-inch size MgO having a purity of 99.5% or more,
Using any target of CaO, SrO, BaO, an alkaline earth composite oxide or a rare earth oxide, or a composite oxide of an alkaline earth oxide and a rare earth oxide,
A plurality of columnar crystallites 14a closely arranged on a glass substrate by sputtering so as to cover the surface of the transparent dielectric layer
To form a film main body 14, which is an aggregate of. The film forming conditions for this film main body were as follows: high-frequency output 1 kW, sputtering pressure 0.5
0 to 3.0 Pa, oxygen concentration with respect to argon gas is 5 to
Preferably, the substrate temperature is 50%, and the substrate temperature is in the range of 20 to 300C. Then, similarly to the above [1], the peripheral side surface and the top surface of the plurality of columnar crystallites 14a constituting the film main body 14 are modified while being held in the gaseous fluorinating agent atmosphere, and the plurality of columnar crystallites are modified. Fluoride layer 1 on peripheral and top surfaces of 14a
5 is formed.

It is manufactured as described in [1] and [2] above.
In the protective film of the PDP, a plurality of
Fluoride is provided on the peripheral side surface and the top surface of the columnar crystallite 14a, respectively.
A layer 15 is formed, and an aggregate of the plurality of columnar crystallites 14a is formed.
Body 14 is covered with a fluoride layer 15
You. For this reason, in the manufacturing process of the PDP 10,
The protective film 22 composed of 14 and the fluoride layer 15 is exposed to the air.
Even if exposed for a long time, MgO etc. in the film body 14
CO_TwoGas or H_TwoIt hardly reacts with O gas. As a result, the membrane
MgO etc. in the main body 14 may impair the function of the PDP 10.
MgCO _ThreeAnd Mg (OH)_TwoTo change into something like
Since there is little, the environmental resistance of the film main body 14 can be improved.

Further, MgO or the like in the film main body 14 is made of MgCO.
_{For 3} or Mg (OH) hardly transformed into ₂ or the like, it is possible to omit the shortening or degassing step degassing process time for removing the MgCO ₃ or Mg (OH) ₂ or the like in a later step, P
The manufacturing cost of the DP 10 can be reduced. Further, since the film body 14 of the protective film 22 having substantially the same thermal expansion coefficient as the dielectric layer 17 of the protective film 22 is bonded to the transparent dielectric layer 17, the protective film 22 does not peel off from the transparent dielectric layer 17 due to thermal cycling. In addition, the adhesion and matching of the protective film 22 to the dielectric layer 17 are extremely improved.

The protective film 22 of the above [1] and [2]
In the formation process of the following [a] or [b]
Preferably, a treatment is applied. [A] Forming film main body 14 on the surface of glass substrate 13 in vacuum
Without exposing the film body 14 to the atmosphere or in a vacuum or
Film body 14 with a gaseous fluorinating agent in an inert gas atmosphere
The peripheral side surface and the top surface of the plurality of columnar crystallites 14a constituting
Peripheral surface and top of the plurality of columnar crystallites 14a.
A plurality of columnar crystallites 14a are formed by forming a fluoride layer 15 on the surface.
Is protected by a fluoride layer 15. the above
The inert gas atmosphere is argon gas or N_TwoGas atmosphere
Preferably, the atmosphere is 4N (99.99).
%) And the dew point is below -65 ° C.
To CO _TwoAnd the concentration of CO is 5.0 ppm by volume or less
Is preferred. By performing such processing, the basic
After forming the film body 14 on the surface of the plate 13,
Peripheral side surfaces of a plurality of columnar crystallites 14a constituting the body 14;
Before forming the fluoride layer 15 on the top surface, the film body 14 is
Harmful to FPD on the surface of the membrane body 14 because it is not exposed to air
Carbonates such as MgO (MgCO_ThreeEtc.) and hydroxides (Mg
(OH)_TwoEtc.) can be prevented or suppressed
You.

[B] A film main body 14 is formed on the surface of the substrate 13 in a vacuum, and after exposing the film main body 14 to the atmosphere, the film main body 14 is fired in the air to form a plurality of pillars constituting the film main body 14. By activating the peripheral side surface and the top surface of the crystallite 14a and further performing a surface treatment with a gaseous fluorinating agent, the fluoride layer 1 is formed on the peripheral side surface and the top surface of the plurality of columnar crystallites 14a.
5 is formed. The firing temperature of the film body 14 in the air is 250 to 550 ° C, preferably 350 to 450 ° C, and the firing time is 0.1 to 24 hours, preferably 0.2 to 24 hours.
One hour. By sintering at the temperature and time within the above ranges, the peripheral side surfaces and the top surfaces of the plurality of columnar crystallites 14a constituting the film main body 14 are activated. Also the above-mentioned air is atmospheric pressure P _t is 0.1 atm ≦ P _t ≦ 5.0 atm (preferably 1.0 atm), N ₂ in the air, O _2, H ₂ O and CO _Z content V of _N2 , V _O2 , V _H2O and V _COZ are as follows. 65% by volume ≦ V _N2 ≦ 5.0% by volume (preferably 7%
8.1% by volume) 10% by volume ≦ VO ₂ ≦ 30% by volume (preferably 2% by volume)
1.0 volume%) 0 volume% ≦ V _H2O ≦ 5 volume% (preferably 2.
0% by volume ≦ V _COZ ≦ 0.1% by volume (preferably 0.1% by volume)
However, z is 1 or 2. The atmosphere may contain other impurity gas (such as Hydrocarbon) in an amount of 0.1% by volume or less.

By performing such processing, the substrate 1
After the film main body 14 is formed on the surface of the substrate 3, the film main body 14 is exposed to the atmosphere, and the peripheral surface and the top surface of the plurality of columnar crystallites 14 a constituting the film main body 14 are harmful to FPD such as carbonates such as MgO. (MgCO ₃ etc.) and hydroxide (Mg (OH) ₂ etc.)
Is generated, the peripheral side surface and the top surface of the plurality of columnar crystallites 14a constituting the film main body 14 are activated by firing the film main body 14 in the atmosphere, and the MgO on the surface of the film main body 14 is activated.
Such as carbonate (MgCO ₃ ) and hydroxide (Mg (OH) ₂
Etc.) are removed as CO ₂ and H ₂ O. In this state, the fluoride layer 15 is formed on the peripheral side surface and the top surface of the plurality of columnar crystallites 14a constituting the film main body 14, so that the film body 14 which is an aggregate of the plurality of columnar crystallites 14a becomes 15 and protected by carbonates such as MgO (MgCO ₃
) And hydroxides (eg, Mg (OH) ₂ ) can be prevented or suppressed.

In the above [a] and [b], the substrate 1 having the film body 14 and the fluoride layer 15 formed on the surface thereof was used.
It is preferable to activate the film main body 14 by baking in the air before, during or after assembling the panel 3. The sintering temperature and the atmosphere for the sintering in the atmosphere are the same as those in the above [b]. Such baking activates the film main body 14, so that even if a slight amount of hydroxide (Mg (OH) ₂ or the like) such as MgO is generated in the film main body 14, it can be removed as H ₂ O, The rate of recontamination of the film main body 14 by the moisture in the atmosphere thereafter can be reduced. Note that in the above embodiment, PD is used as the FPD.
Although P is mentioned, PALC or the like may be used as long as a film main body is formed as a protective film on the surface of the front glass substrate.

[0023]

Next, examples of the present invention will be described in detail together with comparative examples. <Embodiment 1> First, as shown in FIG. 1, an Ag display electrode 16 (5 μm thick) was formed on the surface of a front glass substrate 13 having a thickness of 3 mm.
m) was formed by a screen printing method, and then a transparent dielectric layer 17 (film thickness: 20 μm) made of glass was formed by a screen printing method. Next, the glass substrate 13 was dried at 150 ° C. for 30 minutes in the air, and then fired at 550 ° C. for 30 minutes in the air. Next, a MgO sintered body pellet having a purity of 99.99% is vapor-deposited by an electron beam vapor deposition method so as to cover the surface of the transparent dielectric layer 17 of the glass substrate 13 to form a film as an aggregate of a plurality of columnar crystallites 14a. A body 14 was formed. The film forming conditions for the film main body 14 are as follows: an acceleration voltage of 10 kV, a deposition pressure of 1 × 10 ⁻² Pa,
The deposition distance was 400 mm. Further, the glass substrate 1
3 in an HF gas atmosphere at a pressure of 10 Torr (temperature 80
C) for 1 minute to modify the peripheral side surface and the top surface of the plurality of columnar crystallites 14a constituting the film main body 14, and to coat the fluoride layer 15 on the peripheral side surface and the top surface of the plurality of columnar crystallites 14a. Formed. This glass substrate 13 was used as Example 1.

<Embodiment 2> A film main body, which is an aggregate of a plurality of columnar crystallites 14a, is formed on the surface of a glass substrate by electron beam evaporation in the same manner as in Embodiment 1, and the glass substrate is pressed at a pressure of 50 Torr. HF gas atmosphere (temperature 80
(° C.) for 10 minutes to modify the surface of the film main body to form a fluoride layer on the surface of the film main body. This glass substrate was used as Example 2. <Embodiment 3> After forming a film main body on the surface of a glass substrate by electron beam evaporation in the same manner as in Embodiment 1, the glass substrate was placed in an F ₂ gas atmosphere at a pressure of 10 Torr (at a temperature of 2 Torr).
(5 ° C.) for 1 minute to modify the surface of the membrane main body to form a fluoride layer on the surface of the membrane main body. This glass substrate was used as Example 3.

Example 4 A glass substrate on which a transparent dielectric layer 17 was formed was obtained in the same manner as in Example 1. And purity 9
A 9.9% (Mg, Ca) O sintered pellet is deposited on the transparent dielectric layer 17 of the glass substrate 13 by electron beam evaporation.
The film main body 14, which is an aggregate of a plurality of columnar crystallites 14a, was formed by vapor deposition so as to cover the surface. The conditions for forming the film main body 14 are as follows: an acceleration voltage of 12 kV and a deposition pressure of 1 × 10 ^−2.
Pa and the deposition distance were 400 mm. Further, the glass substrate 13 is held in an HF gas atmosphere at a pressure of 50 Torr (at a temperature of 80 ° C.) for 10 minutes to modify the peripheral side surface and the top surface of the plurality of columnar crystallites 14 a constituting the film main body 14. The fluoride layer 15 was formed on the peripheral side surface and the top surface of the columnar crystallite 14a. This glass substrate was used as Example 4.

Example 5 A glass substrate having a transparent dielectric layer 17 formed thereon was obtained in the same manner as in Example 1. And purity 9
A 9.8% CaO sintered pellet is deposited by electron beam evaporation to cover the surface of the transparent dielectric layer 17 of the glass substrate 13 to form a film body 14 which is an aggregate of a plurality of columnar crystallites 14a. did. The film forming conditions of the film main body 14 are as follows:
The acceleration voltage was 12 kV, the deposition pressure was 1 × 10 ⁻² Pa, and the deposition distance was 400 mm. Further, the glass substrate 13 is placed in an HF gas atmosphere at a pressure of 50 Torr (temperature 80 ° C.).
For 10 minutes to modify the peripheral side surface and the top surface of the plurality of columnar crystallites 14a constituting the film main body 14 to form the fluoride layer 15 on the peripheral side surface and the top surface of the plurality of columnar crystallites 14a. . This glass substrate was used as Example 5.

<Comparative Example 1> In the same manner as in Example 1, the same MgO sintered pellet as in Example 1 was used on the surface of a glass substrate to form a film body, which is an aggregate of a plurality of columnar crystallites 14a, on an electron beam. Although formed by a vapor deposition method, the surface of the film main body was not modified. This glass substrate was used as Comparative Example 1. <Comparative Example 2> A film body which is an aggregate of a plurality of columnar crystallites 14a was formed on the surface of a glass substrate using the same (Mg, Ca) O sintered pellet as in Example 4 as in Example 4. Although formed by electron beam evaporation, the surface of the film body was not modified. This glass substrate was used as Comparative Example 2. <Comparative Example 3> A film main body, which is an aggregate of a plurality of columnar crystallites 14a, was formed on the surface of a glass substrate by electron beam evaporation using the same CaO pellets as in Example 5 as in Example 5. Although formed, the surface of the film body was not modified. This glass substrate was used as Comparative Example 3.

<Comparative Test 1 and Evaluation> The diameter x of the columnar crystallites constituting the film body on the glass substrates of Examples 1 to 5 was measured by observing with a scanning electron microscope, and the peripheral side and top of the columnar crystallites were measured. The thickness y of the fluoride layer formed on the surface was calculated from the atomic weight of fluorine by performing elemental analysis in the depth direction by X-ray photoelectron spectroscopy. Based on this, the ratio y / x between the diameter x of the columnar crystallite and the thickness y of the fluoride layer was determined. Examples 1 to 5
And the outgas amount of the film main body on the glass substrate of Comparative Examples 1-3 was investigated. The degassing amount was evaluated using a temperature rising desorption gas analyzer by expressing the peak area of desorption gas as a relative value (au: arbitrary unit). Therefore, the smaller the relative value of the peak area of the desorbed gas, the better the film body is in environmental resistance. Further, the discharge starting voltage (Vf) of the film main body was set in the chambers of the glass substrates of Examples 1 to 5 and Comparative Examples 1 to 3, and the chamber was evacuated.
Filled with a -4% Xe mixed gas, and measured by applying a voltage of 20 kHz. Table 1 shows the results of these measurements. ◎

[Table 1]

As apparent from Table 1, in Comparative Examples 1 to 3, the relative value of the peak area of the desorbed gas was 1.0 to 1.6a.
u is relatively high, whereas Examples 1 to 5 show smaller values than the corresponding comparative examples, respectively, and are 0.1 to 0.2.
a. u. This is considered to be because the fluoride layer was formed on the peripheral side surface and the top surface of the columnar crystallite constituting the film main body. Further, the discharge starting voltage was 180 in Comparative Example 1, was slightly lower at 174 V in Example 1 corresponding to Comparative Example 1, and was 175 V in Comparative Example 2.
In Example 4 corresponding to Comparative Example 2, the voltage was as low as 162 V. Further, the voltage was 170 V in Comparative Example 3, whereas the voltage in Example 5 corresponding to Comparative Example 3 was as low as 162 V.
As a result, it was found that the secondary electron emission ability was increased, and the performance of the PDP was improved.

[0030]

As described above, according to the present invention, a film main body, which is an aggregate of a plurality of columnar crystallites closely arranged on the surface of a substrate, is formed. Since the fluoride layers were formed on the peripheral side surface and the top surface of the crystallite, respectively, even if the protective film was exposed to the air for a long time in the process of manufacturing the FPD, MgO and the like in the film main body could be changed to the CO ₂ gas or the like in the air. Hardly reacts with H ₂ O gas. As a result, MgO or the like in the film body may impair the function of the FPD.
_Since it hardly changes to ₃ or Mg (OH) ₂ , the environmental resistance of the film body can be improved. In addition, since the main body of the protective film, which has substantially the same thermal expansion coefficient as the substrate, is bonded to the substrate, the protective film does not peel off from the substrate due to thermal cycling, and the adhesion and matching of the protective film to the substrate are extremely good. Becomes

Also, the fluoride layer is MO _X F _Y (M is Mg or the like and 0 ≦ X <2, 0 <Y ≦ 4), or
A fluoride layer is obtained by reacting a gaseous fluorinating agent with MgO, etc., or a gaseous fluorinating agent such as fluorine gas, hydrogen fluoride gas, BF ₃ , SbF ₅ or SF ₄ , or a columnar crystal The ratio of the diameter of the element to the thickness of the fluoride layer is 0.00
When the ratio is 1 or more and 0.2 or less, the above effect can be more remarkably exhibited.

Further, if a film main body is formed on the surface of the substrate and the film main body is subjected to a surface treatment with a gaseous fluorinating agent to form a fluoride layer on the surface of the film main body, Mg in the film main body can be formed.
Harmful MgCO ₃ and Mg for O, such as the functions of the FPD
(OH) ₂ and so on.
The time required for the degassing process for removing CO ₃ and Mg (OH) _{2 and the} like can be reduced or the degassing process can be omitted, and the manufacturing cost of the FPD can be reduced. Further, using the above protective film, FP
By manufacturing D, the number of manufacturing steps of the FPD can be significantly reduced, so that the FPD can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a front substrate on which a protective film of the present invention is formed.

FIG. 2 is a sectional view of an essential part of a PDP in which the front substrate is incorporated.

FIG. 3 is a cross-sectional view taken along the line AA of FIG. 1, showing columnar crystallites having a circular cross section that constitute the protective film.

FIG. 4 shows a cross section of a columnar crystallite having a triangular cross section.
Sectional drawing corresponding to FIG.

[Explanation of symbols]

 Reference Signs List 10 PDP (FPD) 13 Front glass substrate (substrate) 14 Film main body 14a Columnar crystallite 15 Fluoride layer 22 Protective film

Claims (6)

[Claims] 1. A substrate (13) having MgO, CaO, Sr on its surface.
A film main body (14) formed of any of O, BaO, an alkaline earth composite oxide or a rare earth oxide, or a composite oxide of an alkaline earth oxide and a rare earth oxide; A fluoride layer (15) formed on the surface, wherein the film main body (14) is an aggregate of a plurality of columnar crystallites (14a) closely arranged on the surface of the substrate (13), An FPD protective film in which the fluoride layer (15) is formed on the peripheral side surface and the top surface of the plurality of columnar crystallites (14a). 2. The method according to claim 1, wherein the fluoride layer (15) is composed of MO _X F _Y (M is Mg,
Ca, Sr, Ba, an alkaline earth composite metal or a rare earth metal, or a composite metal of an alkaline earth metal and a rare earth metal, where 0 ≦ X <2, 0 <Y ≦ 4. 2. The protective film for FPD according to claim 1, wherein 3. A fluoride layer (15) comprising a gaseous fluorinating agent and M
2. The FPD protection according to claim 1, obtained by reacting with any of gO, CaO, SrO, BaO, an alkaline earth composite oxide or a rare earth oxide, or a composite oxide of an alkaline earth oxide and a rare earth oxide. film. 4. The FPD protective film according to claim ₃ , wherein the gaseous fluorinating agent is one of a fluorine gas, a hydrogen fluoride gas, BF ₃ , SbF _{5 and} SF ₄ . 5. The method according to claim 1, wherein the diameter (x) of the columnar crystallite (14a) and the fluoride layer (1
The protective film for FPD according to any one of claims 1 to 4, wherein a ratio (y / x) of the thickness (y) to the thickness (y) of (5) is from 0.001 to 0.2. 6. The protective film according to claim 1, wherein:
An FPD using (22).