CN1819104A - Plasma display panel with superior light-emitting characteristics - Google Patents

Abstract

The invention provides a PDP with high luminous efficiency and excellent color reproducibility. The PDP comprises a plurality of units formed between a pair of parallel panels, wherein the plurality of units include blue units; a blue fluorescent substance layer is formed in each blue unit; a gas medium is filled in the plurality of units; the blue fluorescent substance layer is made of BaMgAl10B17:Eu; and the length ratio of c axis to a axis in the crystal of the blue fluorescent substance layer is 4.0218 or less.

Description

Plasma display panel with excellent characteristics of luminescence

The application divides an application, the application number of female case is 99809702.0, the applying date of female case is on June 15th, 1999, and the denomination of invention of female case is " having the plasma display panel of the excellent characteristics of luminescence and the method and apparatus of making this plasma display panel ".

Invention field

The present invention relates to a kind of plasma display panel, it is as the display of color TV set etc., and the invention still further relates to the method for making this plasma display panel.

Background of invention

Recently, as use in computer and the television set large-sized, thin and lightweight display, plasma display panel (PDP) has received concern, and the needs of high definition PDP have also been increased.Patent documentation EP0554172A1 discloses the typical technology of a kind of routine relevant with manufacture method with the structure of PDP.

Figure 29 is the cutaway view that shows conventional AC type PDP.

In the figure, a front glass substrate 101 is covered by the stacked structure that becomes with the lower part der group: show electrode 102; Dielectric glass layer 103; With dielectric protective layer 104, wherein dielectric protective layer 104 is made (for example, can referring to Japanese Laid-Open Patent Application No.5-342991) by magnesium oxide (MgO).

After address electrode 106 and partition wall 107 are formed on one on the glass substrate 105.The phosphor layer 110-112 of shades of colour (red, green and blue look) is formed in the space between the partition wall 107.

On the partition wall 107 after front glass substrate 101 is placed on the glass substrate 105, to form the space.Discharge gas is filled in this space, thereby forms discharge space 109.

In having the above-mentioned PDP of this structure, when producing discharge in the discharge space 109, launch vacuum ultraviolet (its wavelength is mainly at 147nm).The phosphor layer 110-112 of every kind of color is subjected to vacuum ultraviolet the exciting of being launched, and forms colored visualization.

Above-mentioned PDP makes by following program.

By on the surface that silver paste is coated in front glass substrate 101 and cure coated silver paste, make show electrode 102.By with the dielectric glass slurry coating on the surface of these (show electrodes) layers and cure coated dielectric glass slurry, form dielectric glass layer 103.Subsequently, on dielectric glass layer 103, form protective layer 104.

By silver paste is coated in the back glass substrate 105 the surface on and cure coated silver paste, make address electrode 106.By on the surface that glass paste bar shaped at a certain distance is coated in these (address electrodes) layers and cure coated glass paste, form partition wall 107.In the space of fluorescent material slurry coating between partition wall, and cure coated slurry at about 500 ℃ and remove resin in the slurry and other component, form phosphor layer 110-112 thus every kind of color.Japanese Laid-Open Patent Application No.2-08834 discloses a kind of technology that forms fluorescent substance film, and it is by coating fluorescent material slurry, is realized by the dry coated slurry of high temperature drying air subsequently.

After having cured fluorescent material, the seal glass material is coated on the perimeter of back glass substrate 105, remove resin and other component in coated seal glass material at the about 350 ℃ seal glass material that cure coating subsequently.(the temporary transient baking process of frit)

Subsequently, front glass substrate 101 and back glass substrate 105 are put together, make show electrode 102 perpendicular to address electrode 106, and electrode 102 is in the face of electrode 106.Then, the temperature (about 450 ℃) by substrate being heated to above the softening point of seal glass makes substrate bonding together.(bonding process)

From the inner space between the substrate (space that forms between front-back baseboard, fluorescent material contacts with this space) gas bleeding the time, the display panel that bonding is got up is heated to about 350 ℃ (air aspiration process).After air aspiration process is finished, supply with discharge gas to the inner space and reach certain pressure (usually in 300 torrs-500 torr scope).

The PDP of Zhi Zaoing problem is how to improve brightness and other characteristics of luminescence as stated above.

In order to address this problem, fluorescent material itself is improved.But, require further improvement the characteristics of luminescence of PDP.

Increasing PDP adopts above-mentioned manufacture method manufacturing.But, the manufacturing cost of PDP is apparently higher than the manufacturing cost of CRT.Therefore, another problem of PDP is to reduce manufacturing cost.

One of multiple possible scheme that reduces cost is minimizing program (man-hour) and the energy that consumes in several technologies of needs heating.

Summary of the invention

Therefore, an object of the present invention is to provide a kind of PDP, and it has high luminous efficiency and excellent color rendition.Another object of the present invention is that a kind of PDP manufacture method will be provided, and wherein temporary transient baking process, bonding process and air aspiration process are to carry out with lower energy consumption in short man-hour, have so just reduced manufacturing cost.

Above-mentioned first purpose is that the colourity by the light that improves the emission of blue fluorescent substance layer realizes.This be by will work as vacuum ultraviolet irradiation blue cell make blue fluorescent substance excite the chromaticity coordinate y (CIE color specification) in time be set at 0.07 or the peak wavelength of lower or spectrum be set at 453nm or shorter the realization.

This improvement of the colourity of the light of aforesaid blue fluorescent substance layer emission has improved from whole unit the colour temperature of (during white balance) light when luminous, and has improved color rendition.

A scheme of the present invention provides a kind of PDP, it is included in a plurality of unit that form between a pair of panel that is parallel to each other, comprise blue cell in these a plurality of unit, in each blue cell, be formed with the blue fluorescent substance layer, these a plurality of unit are filled with gas medium, and wherein the blue fluorescent substance layer is by BaMgAl ₁₀O ₁₇: Eu makes, and the ratio of c shaft length and a shaft length is 4.0218 or littler in the crystal of blue fluorescent substance layer.

Another scheme of the present invention provides a kind of PDP, it is included in a plurality of unit that form between a pair of panel that is parallel to each other, comprise blue cell in these a plurality of unit, in each blue cell, be formed with the blue fluorescent substance layer, these a plurality of unit are filled with gas medium, and wherein the blue fluorescent substance layer is by BaMgAl ₁₀O ₁₇: Eu makes, and when measuring according to the TDS analytic approach, under 200 ℃ or higher temperature, from the H of blue fluorescent substance layer desorb ₂The maximum of the molecular amounts that comprises among the O is 1 * 10 ¹⁶/ gram or still less.

The above-mentioned PDP that the light of blue fluorescent substance layer emission has excellent colourity makes like this: by when dry gas circulate steam forced extraction internally in the space in the inner space, carry out bonding process.

Above-mentioned PDP can also make like this: before bonding process, carries out one and preheats step, and in preheating step, in the space opening between the opposed facing side of panel, heating front panel and rear board in dry gas atmosphere.Perhaps, above-mentioned PDP makes like this: before bonding process, carry out a heating steps, in heating steps, the MgO layer that forms on panel is with when dry gas contacts, the heating panel.

Above-mentioned improvement is realized by manufacture method of the present invention, because this manufacture method has prevented that by reducing the water yield of being detained in the inner space blue fluorescent substance from becoming bad because of heating.On the contrary, in the PDP of routine manufacture method, in bonding process, blue fluorescent substance can become bad because of the heat effects that enters the water in the inner space, causes the luminous intensity and the colourity reduction of the light launched.

The above-mentioned PDP that the light of blue fluorescent substance layer emission has excellent colourity also can make like this: carry out bonding process, subsequently when dry gas is circulated in the inner space, the panel of bonding is heated to certain temperature, and begins a pump step.

Adopt said procedure, even the colourity of the light of blue fluorescent substance layer emission is owing to the heat effects of the water in the bonding process becomes bad, colourity also can be recovered, because when the panel of bonding is heated to uniform temperature, when dry gas circulation time in the inner space, water is removed in the space internally.

Here, " dry gas " is meant that the partial pressure of the steam that is comprised is lower than the gas of conventional partial pressure.The preferred air (dry air) that is dried and handles that uses.

Hope is set at 15 torrs or lower with the partial pressure of steam in the dry gas atmosphere, and is preferably set to 10 torrs or lower, 5 torrs or lower, 1 torr or lower, 0.1 torr or lower.Hope is set at 20 ℃ or lower with the dew point temperature of dry gas, and be preferably set to 10 ℃ or lower, 0 ℃ or lower ,-20 ℃ or lower ,-40 ℃ or lower.

Also can make from the improved above-mentioned PDP of colourity of the light of blue fluorescent substance layer emission: wherein, in the space opening between the opposed facing side of front and back panel, front and back panel is temporarily cured by such PDP manufacture method; When circulating in the inner space of dry gas between panel, make the front and back panel bonding; Perhaps, after preheating in the space opening between the opposed facing side of front and back panel, front and back panel is bonded together.

Second purpose of the present invention can realize by the following method: wherein, by keeping after sticking temperature bonds together front panel and rear board by the seal, sealing materials between the panel, the beginning air aspiration process, simultaneously not with panel from the sticking temperature cool to room temperature, and gas bleeding the inner space between panel; Perhaps realize by the following method: wherein, by keeping after temporary transient bonding temp temporarily cures front panel and rear board and seal, sealing materials therebetween, the beginning bonding process, simultaneously not with panel from temporary bonding temperature cool to room temperature.

In the manufacture process of reality, each in these heating processes all is to use a heating furnace to carry out.Usually, the temporary transient baking process of seal, sealing materials, bonding process and air aspiration process are separately carried out, and the each between these technologies every in all with the panel cool to room temperature.Adopt this program, for heating panel in each technology needs long time and will consume lot of energy.By contrast, in the present invention, these technologies are to carry out not needing temperature is reduced under the situation of room temperature.This has just reduced and has heated required time and energy.

The accompanying drawing summary

Fig. 1 is the cutaway view of major part of the AC type discharge PDP of embodiment 1.

Fig. 2 demonstrates a kind of PDP display device, and it comprises the PDP shown in Fig. 1 and an exciting circuit that is connected to PDP.

Fig. 3 demonstrates a kind of conveyor belt type firing equipment that uses among the embodiment 1.

Fig. 4 demonstrates the structure of the sealing-in firing equipment that uses among the embodiment 1.

Fig. 5 demonstrates from the measurement result of the relative luminous intensity of the light of blue fluorescent substance emission, and these results measure when at the different air baking of the partial pressure of contained steam.

Fig. 6 demonstrates from the measurement result of the chromaticity coordinate y of the light of blue fluorescent substance emission, and these results measure when at the different air baking of the partial pressure of contained steam.

Fig. 7 A-7C demonstrates from the H of blue fluorescent substance desorb ₂The measurement result of the molecular amounts in the O gas.

Fig. 8-16 demonstrates the object lesson of embodiment 2, and these examples relate to the mode of the position of pore on the perimeter of back glass substrate and the coating of seal glass material.

Figure 17 and 18 demonstrates the relation between the partial pressure of the recovery effects of the characteristics of luminescence that becomes bad and steam, and wherein the blue fluorescent substance layer has become bad and cured once more in air subsequently.

Figure 19 demonstrates the structure of the stamping device that uses in the bonding process of embodiment 5.

Figure 20 is the in-built stereogram that shows the heating furnace of the stamping device shown in Figure 19.

Figure 21 A-21C demonstrates the operation of stamping device in preheating technology and bonding process.

Figure 22 demonstrates the result of the test of embodiment 5, has wherein measured the quantity of steam that discharges from the MgO layer in the time in (heating).

Figure 23 demonstrates a kind of modification of the stamping device among the embodiment 5.

Figure 24 A-24C demonstrates the operation of carrying out according to the another kind of modification of the stamping device among the embodiment 5.

Figure 25 only demonstrates from the spectrum of the blue cell emission of the PDP of embodiment 5.

Figure 26 is an XYZ chromaticity diagram, demonstrates near blue color rendering zone embodiment 5 and PDP comparative example on it.

Figure 27 A, 27B and 27C demonstrate the operation of using in the air aspiration process process stamping device of embodiment 6 to carry out at temporary transient baking process.

Figure 28 demonstrates the Temperature Distribution of using in temporary transient baking process, bonding process and air aspiration process when making the display panel of embodiment 6.

Figure 29 is the cutaway view that shows conventional AC type PDP.

Preferred embodiment is described

＜embodiment 1 〉

Fig. 1 is the cutaway view of the major part of the AC type discharge PDP in the present embodiment.This figure demonstrates the viewing area at the center that is positioned at PDP.

This PDP comprises: front panel 10, and it is to be made of front glass substrate 11, dielectric layer 13 and the protective layer 14 that forms on it, substrate 11 has show electrode 12 (it is divided into scan electrode 12a and keeps electrode 12b); And rear board 20, it is to be made of back glass substrate 21 and the dielectric layer 23 that forms on it, substrate 21 has address electrode 22.Front panel 10 and rear board 20 are provided with like this: show electrode 12 and address electrode 22 face with each other.Space between front panel 10 and the rear board 20 is divided into a plurality of arc chambers 30 by the partition wall 24 of bar shaped.Each arc chamber is filled with discharge gas.

Phosphor layer 25 is formed on the rear board 20, makes the phosphor layer that each arc chamber 30 has a kind of color in the red, green and blue, and phosphor layer is by the order repeated arrangement of color.

In this display panel, show electrode 12 and address electrode 22 form bar shaped respectively, and show electrode 12 is perpendicular to partition wall 24, and address electrode 22 is parallel to partition wall 24.Each infall at show electrode 12 and address electrode 22 forms a unit, and this element has a kind of color in the red, green and blue.

Address electrode 22 is made by metal (for example silver or Cr-Cu-Cr).In order to keep low show electrode resistance and to guarantee big machining area in the unit, wish that each show electrode 12 is made up of a plurality of bus electrodes, these bus electrodes (being made by silver or Cr-Cu-Cr) have little width, they overlap on the transparency electrode, and transparency electrode has big width and by such as ITO, SnO ₂Make with the conducting metal oxide of ZnO and so on.But, show electrode 12 can be made from silver as address electrode 22.

Dielectric layer 13 is layers that are made of dielectric substance, and it covers the whole surface of a side that comprises show electrode 12 of front glass substrate 11.Dielectric layer is normally made by the low melting point lead glass, though it also can be made by the lamination of low melting point bismuth glass or low melting point lead glass and low melting point bismuth glass.

Protective layer 14 is made by magnesium oxide, and it is the thin layer on the whole surface of a dielectric layer 13.

Dielectric layer 23 is similar to dielectric layer 13, but it also is mixed with TiO ₂Particle is so that this layer also plays the effect of visible light reflecting layer.

Partition wall 24 is made by glass, and it forms on the surface of the dielectric layer 23 of plate 20 in the back outstanding.

Below be the fluorescent material that is used for present embodiment:

Blue fluorescent substance BaMgAl ₁₀O ₁₇: Eu

Green fluorescence material Zn ₂SiO ₄: Mn

Red fluorescent material Y ₂O ₃: Eu

The composition of material therefor is essentially identical among the PDP of the composition of these fluorescent materials and routine.But, compare with regular situation, the fluorescent material of present embodiment is launched the light of better color.This is owing to added heat in the manufacturing process becomes bad because of fluorescent material.Here, the light of launching better color means: from the chromaticity coordinate y little (promptly the peak wavelength of Fa She blue light is short) of the light of blue cell emission, and near blue color rendering zone is wide.

In typical conventional PDP, when having only blue cell luminous, from the chromaticity coordinate y (CIE color specification) of the light of blue cell emission be 0.085 or bigger (promptly, the peak wavelength of radiative spectrum is 456nm or longer), and do not having under the situation of colour correction, the colour temperature during white balance (when and colour temperature when forming white developing all luminous from blue, redness and green cell) is about 6000K.

The technology of the colour temperature during as the raising white balance, following technology is known: only the width (spacing of partition wall) with blue cell is set at big value, and the area of blue cell is set at than redness or the big value of green cell.But, colour temperature is set at 7000K or higher according to this technology, the area of blue cell should be redness or green cell 1.3 times of area or bigger.

By contrast, in the PDP of present embodiment, when having only blue cell luminous, be 0.08 or littler from the chromaticity coordinate y of the light of blue cell emission, the peak wavelength of radiative spectrum is 455nm or shorter.Under these conditions, do not having under the situation of colour correction, the colour temperature during white balance can be brought up to 7000K or higher.In addition, according to the condition in the manufacturing process, can further reduce chromaticity coordinate y, perhaps not have under the situation of colour correction, the colour temperature during with white balance is brought up to 10000K or higher.

As mentioned above, along with the chromaticity coordinate y of blue cell (light of emission) diminishes, the peak wavelength of the blue light of being launched shortens.This will be illustrated in the embodiment 3 and 5 of back.

The embodiment of back also will illustrate: why the chromaticity coordinate y along with blue cell (light of emission) diminishes, and the color rendering zone becomes big; What kind of relation is the colour temperature of the chromaticity coordinate y of the light of blue cell emission during with white balance under not having the situation of colour correction be.

In the present embodiment, suppose that this PDP is used for 40 inches high definition TV, the thickness setting of dielectric layer 13 is about 20 μ m so, and the thickness setting of protective layer 14 is about 0.5 μ m.In addition, the height setting of partition wall 24 is 0.1mm-0.15mm, and the spacing of partition wall is set at 0.15mm-0.3mm, and the thickness setting of phosphor layer 25 is 5 μ m-50 μ m.Discharge gas is a Ne-Xe gas, and wherein Xe accounts for 50% volume.Inflation pressure is set at 500 torrs-800 torr.

This PDP is by following procedure activation: as shown in Figure 2, a display panel drives exciting circuit 100 and is connected to PDP.Apply certain voltage by the zone between show electrode 12a that wants luminescence unit and address electrode 22, the calculated address discharge.Subsequently, apply a pulse voltage, form and keep discharge by the zone between show electrode 12a and 12b.When discharge was carried out, ultraviolet ray was launched in the unit.The ultraviolet ray of being launched is converted to visible light by phosphor layer 25.By above process, when the unit was luminous, image just was presented on the PDP.

Make the process of PDP

It below is explanation to the manufacture process of PDP with above-mentioned structure.

Make front panel

Front panel 10 is to make like this: form show electrode 12 on front glass substrate 11; Cover show electrode with dielectric layer 13; On the surface of dielectric layer 13, form protective layer 14 subsequently.

Show electrode 12 is to make like this: silver paste is coated on the surface of front glass substrate 11 with method for printing screen, cures the silver paste of coating subsequently.Dielectric layer 13 is to form like this: coating lead glass material (for example, the boron oxide (B of the lead oxide of 70 weight % (PbO), 15 weight % ₂O ₃) and the silica (SiO of 15 weight % ₂)), cure the material of coating subsequently.The protective layer 14 that is made of magnesium oxide (MgO) is to adopt method such as vacuum vapor deposition to be formed on the dielectric layer 13.

Make rear board

Rear board 20 is to make like this: calculated address electrode 22 on the glass substrate 21 of back; With dielectric layer 23 (visible light reflecting layer) overlay address electrode; On the surface of dielectric layer 23, form partition wall 30 subsequently.

Address electrode 22 is to make like this: with method for printing screen silver paste is coated on the surface of back glass substrate 21, cures the silver paste of coating subsequently.Dielectric layer 23 is to form like this: will contain TiO ₂The slurry coating of particle and dielectric glass particle cures the slurry of coating subsequently on the surface of address electrode 22.Partition wall 30 is to form like this: the slurry that will comprise glass particle with method for printing screen repeatedly applies at a certain distance, cures the slurry of coating subsequently.

After making rear board 20, the fluorescent material slurry of preparation red, green and blue look, and with method for printing screen with these slurry coatings in the space between the partition wall.Phosphor layer 25 is to form by the slurry in the air baking coating, as described later.

The fluorescent material slurry for preparing every kind of color by following process.

Blue fluorescent substance (BaMgAl ₁₀O ₁₇: Eu) obtain by following steps.At first, in Ba: the atomic ratio of Mg: Al is that 1: 1: 10 ratio is with brium carbonate (BaCO ₃), magnesium carbonate (MgCO ₃) and aluminium oxide (α-Al ₂O ₃) these materials are mixed with mixture.Next step is with a certain amount of europium oxide (Eu ₂O ₃) add in the said mixture.Subsequently, with an amount of flax (flax) (AlF ₂, BaCl ₂) mix in grinder with this mixture.With resulting mixture under 1400 ℃-1650 ℃ temperature at reducing atmosphere (H ₂, N ₂) in cure cycle regular hour (for example 0.5 hour).

Red fluorescent material (Y ₂O ₃: Eu) obtain by following steps.At first, with a certain amount of europium oxide (Eu ₂O ₃) add hydroxide iridium (Y to ₂(OH) ₃) in.Subsequently, an amount of flax is mixed in grinder with this mixture.With resulting mixture under 1200 ℃-1450 ℃ temperature in cycle air baking regular hour (for example 1 hour).

Green fluorescence material (Zn ₂SiO ₄: Mn) obtain by following steps.At first, be 2: 1 ratio in the atomic ratio of Zn: Si, with zinc oxide (ZnO) and silica (SiO ₂) these materials are mixed with mixture.Next step is with a certain amount of manganese oxide (Mn ₂O ₃) add in the said mixture.Subsequently, an amount of flax is mixed in grinder with this mixture.With resulting mixture under 1200 ℃-1350 ℃ temperature in cycle air baking regular hour (for example 0.5 hour).

Subsequently, pulverize and screen, to obtain the particle that specified particle size distributes that has corresponding to every kind of color for the fluorescent material of every kind of color making in a manner described.By with particle and adhesive and solvent, just obtained the fluorescent material slurry of every kind of color.

Phosphor layer 25 also can adopt the method except that silk screen printing to form.For example, phosphor layer can form like this: make a mobile nozzle ejection fluorescent material printing ink; Perhaps, prepare a photosensitive resin thin slice that comprises fluorescent material, on the surface of that side that comprise partition wall 24 of this thin slice attached to back glass substrate 21, carry out photoetching composition, then to the thin slice that adheres to develop remove accompanying thin slice do not need part.

Bonding front panel and rear board vacuumize and fill discharge gas

Coating seal glass material forms the seal glass layer on one of the front panel of making in a manner described 10 and rear board 20 or both.The seal glass layer is temporarily cured, and to remove resin and other composition from frit, this will describe in detail in the back.Subsequently, front panel 10 is so put together with rear board 20: show electrode 12 is faced mutually with address electrode 22 and is vertical mutually.Then, front panel 10 and rear board 20 are heated, so that they bond together by softening seal glass layer.This will describe in detail in the back.

Cure the panel (curing 3 hours under 350 ℃ of temperature) of bonding, air-out the space between the panel that is bondd simultaneously is to form vacuum.The discharge gas with mentioned component be filled into by certain pressure in the space between the panel of boning after, PDP has just finished.

Cure fluorescent material, temporarily cure the detailed description of seal glass material and bonding front panel and rear board technology

To explain below and cure fluorescent material, temporarily cure the technology of seal glass material and bonding front panel and rear board.

Fig. 3 demonstrates a kind of conveyor belt type firing equipment, and this equipment is used to cure fluorescent material and temporarily cures frit.

Firing equipment 40 comprises: a heating furnace 41 is used for heated substrates; A conveyer belt 42 is used at heating furnace 41 conveying substrates; And a gas introduction tube 43, be used for protective gas (atmospheric gas) is imported heating furnace 41.Heating furnace 41 is inner, and to be provided with a plurality of heaters (not shown along adding hot conveyer belt.)

By being adjusted at inlet 44 and exporting between 45 near a plurality of heaters that are provided with along conveyer belt temperature, can adopting arbitrarily, Temperature Distribution heats substrate.In addition, heating furnace can be filled the protective gas that injects by gas introduction tube 43.

Dry air can be used as protective gas.Dry air is to form like this: make air pass through a gas-drying apparatus (not shown), this drier cools air to low temperature (subzero 10 ℃); Make the airborne vapor condensation of cooling.Reduce the quantity of steam in the cooling air (partial pressure) by this process, and obtained dry air at last.

In order to cure fluorescent material, in firing equipment 40, in dry air, the back glass substrate 21 that is formed with phosphor layer 25 on it is cured (curing 10 minutes) under 520 ℃ of maximum temperatures.Be appreciated that from the above description by in dry gas, curing fluorescent material, alleviated in curing the process of fluorescent material because the change that the steam in heating and the environment causes is bad.

The partial pressure of steam is low more in the dry air, for alleviating owing to the bad effect of the fluorescence qualitative change that causes of heating is good more.Therefore, the partial pressure of wishing steam is 15 torrs or lower.When the partial pressure of steam is set to lower value, for example 10 torrs or lower, 5 torrs or lower, 1 torr or lower, 0.1 torr or when lower, it is more remarkable that above-mentioned effect can become.

There is certain relation between the partial pressure of steam and the dew point temperature.Therefore, more than explanation can be rewritten by the partial pressure that substitutes steam with dew point temperature.That is, dew point temperature is set lowly more, for alleviating owing to the bad effect of the fluorescence qualitative change that causes of heating is good more.Therefore, the dew point temperature of wishing dry gas is set at 20 ℃ or lower.When the dew point temperature of dry gas is set to lower value, for example 0 ℃ or lower ,-20 ℃ or lower ,-40 ℃ or when lower, it is more remarkable that above-mentioned effect can become.

In order temporarily to cure the seal glass material, in firing equipment 40, in dry air, the front glass substrate 11 that is formed with seal glass layer 25 on it or back glass substrate 21 are cured (curing 30 minutes) under 350 ℃ of maximum temperatures.

In above-mentioned baking process, in this temporary transient baking process, the partial pressure of wishing steam is 15 torrs or lower.In addition, when the partial pressure of steam is set to lower value, for example 10 torrs or lower, 5 torrs or lower, 1 torr or lower, 0.1 torr or when lower, it is more remarkable that above-mentioned effect can become.In other words, wish that the dew point temperature of dry gas is set at 20 ℃ or lower, and wish that more this temperature is set at lower value, for example 0 ℃ or lower ,-20 ℃ or lower ,-40 ℃ or lower.

Fig. 4 demonstrates the structure of sealing-in firing equipment.

Sealing-in firing equipment 50 comprises: a heating furnace 51 is used for heated substrates (being front panel 10 and rear board 20 in the present embodiment); A conduit 52a is used for protective gas from the outside importing front panel 10 of heating furnace 51 and the space between the rear board 20; And conduit 52b, be used for protective gas is drawn out to from the space between front panel 10 and the rear board 20 outside of heating furnace 51.Conduit 52a is connected to a source of the gas 53, and source of the gas 53 is used to supply with the dry air as protective gas.Conduit 52b is connected to a vacuum pump 54.In order to adjust flow velocity, be separately installed with adjuster valve 55a and 55b on conduit 52a and the 52b by the gas of conduit.

Employing has the sealing-in firing equipment 50 of above-mentioned structure, by following mode front panel and rear board is bonded together.

In the outer peripheral areas of viewing area, rear board is provided with pore 21a and 21b.Glass tube 26a links to each other with 21b with pore 21a respectively with 26b.Should be pointed out that and in Fig. 4, omitted the partition wall and the fluorescent material that should be positioned on the rear board 20.

Front panel 10 and rear board 20 adopt seal glass layer therebetween to be positioned properly, and it is placed in the heating furnace 51 subsequently.When so operating, the most handy anchor clamps or similar device clamp the front panel 10 and the rear board 20 of location, with anti-offset.

Adopt vacuum pump 54, will extract out the space of air between panel, to form vacuum therein.Subsequently,, dry air is transported in this space, does not use vacuum pump 54 simultaneously by certain flow velocity by conduit 52a.Dry air is extracted out from conduit 52b.This means flow through space between the panel of dry air.

Then, when dry air is flowed through space between the panel, front panel 10 and rear board 20 are heated (heating is 30 minutes under the highest 450 ℃ of temperature).In this process, front panel 10 and rear board 20 are bonded together by softening seal glass layer 15.

After finishing bonding, stop up among glass tube 26a and the 26b, and vacuum pump is connected to another glass tube.This sealing-in firing equipment just is used for next technology, is evacuation process.In the discharge gas filling process, a gas cylinder that comprises discharge gas is connected to another glass tube, and discharge gas is filled in the space between the panel by operations platoon's device of air.

The effect of the method for showing in the present embodiment

The bonding front panel of showing in the present embodiment and the method for rear board have unique effect, and this will be illustrated below.

Generally speaking, the gas resemble steam is to be trapped in the lip-deep of front panel and rear board because of absorption.When the heating panel, the gas of absorption just is released.

In the method for routine, in the bonding process behind temporary transient baking process, at first front panel and rear board are at room temperature put together, heating bonds together them then.In bonding process, the lip-deep gas that is retained in front panel and rear board because of absorption is released.Though a certain amount of gas is released in temporary transient baking process, when panel at room temperature was placed in the air, gas was detained to get off because of absorption again before bonding process begins, and these gases discharge in bonding process.The gas that discharges is limited in the little space between the panel.Can learn that by measuring this moment, the partial pressure of the steam in this space was generally 20 torrs or higher.

When this happens, because heating and be limited in the effect of gas in this space (in these gases, especially the steam that discharges of protective layer 14), the phosphor layer 25 of space contact is tending towards becoming bad therewith.The bad luminous intensity of these layers (especially blue fluorescent substance layer) that causes of the change of phosphor layer reduces.

On the other hand, according to the method for showing in the present embodiment, because dry air is flowed through during panel that from then on space drainage is to outside for this space and steam in heating, therefore this change is bad is alleviated.

In this bonding process, as the fluorescent material baking process, the partial pressure of wishing steam is 15 torrs or lower.In addition, when the partial pressure of steam is set at lower value, for example 10 torrs or lower, 5 torrs or lower, 1 torr or lower, 0.1 torr or when lower, the change that can alleviate fluorescent material to a greater degree is bad.In other words, wish that the dew point temperature of dry air is set at 20 ℃ or lower, and wish that more this temperature is set at lower value, for example 0 ℃ or lower ,-20 ℃ or lower ,-40 ℃ or lower.

The research of the partial pressure of steam in the protective gas

Test shows: by reducing the partial pressure of steam in the protective gas, can prevent because the change of the blue fluorescent substance that heating causes is bad.

Fig. 5 and 6 demonstrates blue fluorescent substance (BaMgAl respectively ₁₀O ₁₇: Eu) relative luminous intensity of Fa She light and chromaticity coordinate y.These numerical value are in air blue fluorescent substance to be cured measurement afterwards by the partial pressure that repeatedly changes steam.The maximum temperature that blue fluorescent substance cures is 450 ℃, and holding time is 20 minutes.

Relative luminous intensity value shown in Fig. 5 is the relative value when the luminous intensity of measured blue fluorescent substance before curing is set at standard value 100.

In order to obtain luminous intensity, at first use the emission spectrum of spectrometer measurement phosphor layer, calculate chromaticity coordinate y from measured emission spectrum afterwards, adopt chromaticity coordinate y that calculates and the brightness of measuring in advance then, obtain luminous intensity according to formula (luminous intensity=brightness/chroma coordinate y).

Should be pointed out that it is 0.052 that blue fluorescent substance cures chromaticity coordinate y before.

Can find from the result shown in Fig. 5 and 6: when the partial pressure of steam was about 0 torr, luminous intensity did not reduce because of heating, and colourity does not change.But, should be noted in the discussion above that the increase along with the partial pressure of steam, the relative luminous intensity of blue fluorescent substance reduces, and the chromaticity coordinate y of blue fluorescent substance increases.

It has been generally acknowledged that: as blue fluorescent substance (BaMgAl ₁₀O ₁₇: when Eu) being heated, luminous intensity reduces, and chromaticity coordinate y increase, because by heating, activator Eu ²⁺Ion is oxidized and be converted to Eu ³⁺Ion (see S.Oshio, T.Matsuoka, " oxidation causes fluorescent material BaMgAl at ECS's magazine 145 volume o. 11th (in November, 1988) articles that the 3903-3907 page or leaf is delivered for S.Tanaka and H.Kobayashi ₁₀O ₁₇: Eu ²⁺The mechanism that reduces of brightness ").But, consider with the fact that the partial pressure of steam the atmosphere changes, can think Eu from the chromaticity coordinate y of above-mentioned blue fluorescent substance ²⁺Ion not with protective gas (for example air) in oxygen directly react, but the steam in the protective gas has quickened and the bad relevant reaction of this change.

In order to compare,, measured blue fluorescent substance (BaMgAl corresponding to multiple heating-up temperature ₁₀O ₁₇: the variation of the reduction of luminous intensity Eu) and chromaticity coordinate y.Measurement result presents such trend: along with heating-up temperature uprises, the reduction of luminous intensity increases in 300 ℃-600 ℃ scope, and the partial pressure along with steam uprises under heating-up temperature arbitrarily, and the reduction of luminous intensity increases.On the other hand, though measurement result presents the trend that uprises the variation increase of chromaticity coordinate y along with the partial pressure of steam, measurement result does not present the trend that chromaticity coordinate y changes with heating-up temperature.

In addition; measured the quantity of steam that discharges when every kind of material is heated, these materials are the materials that constitute front glass substrate 11, show electrode 12, dielectric layer 13, protective layer 14, back glass substrate 21, address electrode 22, dielectric layer 23 (visible light reflecting layer), partition wall 24 and phosphor layer 25.According to measurement result, the quantity of steam maximum that discharges of the material MgO of protective layer 14 wherein.Can think from these measurement results: the change of the phosphor layer 25 that produces because of heating bonding process is bad mainly to be to be caused by the steam that protective layer 14 discharges.

The mapping mode of present embodiment

In the present embodiment, in bonding process, in the inner space between a certain amount of dry air inflow panel.But, can alternately repeat following steps: the space formation vacuum that deflates internally; Inject dry air.By this mode of operation, can extract steam out in the space internally effectively, and it is bad to alleviate the change of the phosphor layer that causes because of heating.

In addition, phosphor layer baking process, temporary transient baking process and bonding process needn't all carry out in the protectiveness dry gas.One or two technology in these technologies carries out just can obtaining identical effect in the protectiveness dry gas.

In the present embodiment, in bonding process, as the inner space between the dry air inflow panel of protective gas.But, do not react and for example nitrogen inflow of the strong low inert gas of its vapor partial pressure, also can obtain certain effect with phosphor layer by making.

In the present embodiment, in bonding process, inner space between the panel 10 and 20 is injected in dry air pressurization by glass tube 26a.But, adopt for example firing equipment shown in Fig. 3 40, also can in dry air atmosphere, panel 10 and 20 be bonded together.In this case, also can obtain certain effect, because a spot of dry air has flowed into the inner space by pore 21a and 21b.

Though do not describe in the present embodiment, when the front panel 10 that is formed with protective layer 14 on its surface cured in the protectiveness dry gas, the lip-deep water yield that is trapped in protective layer 14 because of absorption can reduce.Only have this specific character, the change of blue fluorescent substance layer is bad just to be restricted to certain degree.Combine with the manufacturing process of present embodiment by this method that will cure front panel 10, can expect further reinforced effects.

PDP according to the method manufacturing of present embodiment has the effect that reduces the paradoxical discharge in the PDP process of motivation, because phosphor layer comprises a spot of water.

Example 1

＜table 1 〉

Table 1

The display panel structure and the characteristics of luminescence
									The display panel numbering	The partial pressure of steam (torr) in the protective gas			Display panel brightness (cd/m 2)	Colour temperature (k) when the whole unit from display panel are luminous	The peak strength of the spectrum of blue light and green glow is than (blue/green)	Adopt TDS to analyze under 200 ℃ or higher temperature H from the blue fluorescent substance desorb 2The maximum quantity of molecule in the O gas	The axial length of blue fluorescent substance crystal is than (c-axle/a-axle)
Cure fluorescent material	Temporarily cure the seal glass material	The bonding panel
			1 2 3 4 5	12.0 8.0 3.0 0.0 20.0	12.0 8.0 3.0 0.0 20.0	12.0 8.0 3.0 0.0 20.0	495 520 540 550 470	7100 7500 8400 9000 6300		0.80 0.88 1.02 1.10 0.76	1.0×10 16 7.9×10 15 5.3×10 15 2.2×10 15 2.6×10 16	4.02180 4.02177 4.02172 4.02164 4.02208

In table 1, display panel 1-4 is the PDP that makes according to present embodiment.Display panel 1-4 makes like this: in phosphor layer baking process, the temporary transient baking process of frit and bonding process, the vapor partial pressure in the dry air of flowing through is different by force, and vapor partial pressure is by force in 0 torr-12 torr scope.

Display panel 5 is the PDP that make in order to compare.Display panel 5 is to make like this: in phosphor layer baking process, the temporary transient baking process of frit and bonding process, what flow through is non-dry air (vapor partial pressure is by force 20 torrs).

In each of PDP 1-5, the thickness of phosphor layer is 30 μ m, and discharge gas Ne (95%)-Xe (5%) fills by the inflation pressure of 500 torrs.

Characteristics of luminescence test and result

For among display panel (PDP) 1-5 each, as the characteristics of luminescence, display panel brightness when having measured under not having colour correction situation white balance and colour temperature (for producing white developing) and from the peak strength of the spectrum of the light of blue cell emission and ratio from the peak strength of the spectrum of the light of green cell emission from all indigo plants, display panel brightness and colour temperature when red and green cell is luminous.

The result of this test has been shown in the table 1.

Each PDP of manufacturing is taken apart, and use the krypton Excimer lamp that the blue fluorescent substance layer of rear board is carried out vacuum ultraviolet (centre wavelength is 146nm) irradiation.Colour temperature when subsequently, measuring light is from the emission of all red, green and blue color elements and from the spectrum of blue cell emission with from the ratio of the peak strength of the spectrum of green cell emission.Owing to do not use colour filter or like in the front panel of making, the result is identical with above-mentioned result.

Then, take out blue fluorescent substance from panel.Adopt TDS (thermal desorption) analytic approach, measure a gram H of desorb from blue fluorescent substance ₂The molecular number that comprises in the O gas.In addition, by X-ray analysis, measure the c shaft length of blue fluorescent substance crystal and the ratio of a shaft length.

Above-mentioned measurement is that the infrared heating type TDS analytical equipment that adopts ULVAC Japan Co., Ltd to make is carried out in the following manner.

Each specimen that is included in the fluorescent material in the tantalum dish is placed in the room of tentatively bleeding, and from room, bleeds and reach 10 ^-4The vacuum degree of Pa magnitude.Subsequently, specimen is placed measuring chamber, and from this chamber, bleed and reach 10 ^-7The vacuum degree of Pa magnitude.With scan mode, according to 15 seconds measurements at interval, measure H from the fluorescent material desorb ₂The quantity of O molecule (mass number is 18) simultaneously, adopts infrared heater that specimen is heated, and is heated to 1100 ℃ by 10 ℃/minute the rates of heat addition from room temperature.Fig. 7 A, 7B and 7C demonstrate respectively from the test result of display panel 2,4 and 5 blue fluorescent substances that take out.

As can be seen from the figure, from the H of blue fluorescent substance desorb ₂The quantity of O molecule has peak value at about 100 ℃-200 ℃ and about 400 ℃-600 ℃.Can understand like this: in of the desorb of about 100 ℃-200 ℃ peak value owing to physical absorption gas, and in the desorb of about 400 ℃-600 ℃ peak value owing to chemisorbed gas.

Table 1 shows the H of desorb under 200 ℃ or higher temperature ₂The peak value of O molecular number is promptly at the H of about 400 ℃ of-600 ℃ of desorbs ₂The peak value of O molecular number also shows the c shaft length of blue fluorescent substance crystal and the ratio of a shaft length.

Analyze

Result by shown in the analytical table 1 can draw: aspect the characteristics of luminescence, the display panel 1-4 of present embodiment is better than display panel 5 (comparative example).That is, display panel 1-4 has higher display panel brightness and colour temperature.

In display panel 1-4, the order that the characteristics of luminescence is pressed display panel 1,2,3,4 improves.

Can find from this result: because the partial pressure of steam is lower phosphor layer baking process, the temporary transient baking process of frit and bonding process, therefore, the characteristics of luminescence (display panel brightness and colour temperature) becomes better.

The reason that above-mentioned phenomenon produces can be understood as: when the partial pressure of steam reduces, prevented blue fluorescent substance layer (BaMgAl ₁₀O ₁₇: Eu) become bad, and chromaticity coordinate y value diminishes.

In the panel of present embodiment, under 200 ℃ or higher temperature, from every gram H of blue fluorescent substance desorb ₂The molecular number maximum that comprises in the O gas is 1 * 10 ¹⁶Or littler, and the ratio of the c shaft length of blue fluorescent substance crystal and a shaft length is 4.0218 or littler.By contrast, compare the respective value of display panel all greater than above-mentioned value.

＜embodiment 2 〉

The PDP of present embodiment has the PDP identical construction with embodiment 1.

The mode difference of the position of pore and seal glass material coating, the manufacture method of PDP also is identical with embodiment 1 on the perimeter of back glass substrate 21.In bonding process; more worsen in change ratio of less inequality phosphor layer baking process that phosphor layer causes because of heating and the temporary transient baking process of frit; because in bonding process; when when heating, comprise in each little inner space that the gas of the steam that produces protective layer, phosphor layer and the seal glass from front panel is limited in being separated by partition wall.Under the circumstances, be designed in the present embodiment: in bonding process, the dry air that injects the inner space space between the partition wall of can stably flowing through, and the gas that produces in the space between partition wall is extracted out effectively.This has just strengthened and prevents to become bad effect because of heating causes phosphor layer.

Fig. 8-16 shows multiple concrete execution mode, and they relate to the mode of the position of pore on the perimeter of back glass substrate 21 and the coating of seal glass material.All be provided with the partition wall 24 of strip though should be pointed out that rear board 20 in fact on whole image displaying area territory, Fig. 8-16 only shows several partition walls 24 in each side, has omitted the partition wall of core.

As shown in these figure, the seal glass zone 60 of shaped as frame (forming the zone of seal glass layer 15 on it) is arranged on the perimeter of back glass substrate 21.Seal glass zone 60 comprises: a pair of vertical sealing region 61, and they extend along outermost partition wall 24; With the sealing region 62 of a pair of level, they extend (on the Width of partition wall) perpendicular to partition wall.

When panel bonds together, the dry air gap 65 between the partition wall 24 of flowing through.

The feature of these examples is described below with reference to accompanying drawings.

Shown in Fig. 8-12, on the diagonal position of 60 inboards, seal glass zone, be formed with pore 21a and 21b.When panel bonded together, the dry air (as shown in Figure 4) that imports from pore 21a flow through the gap 63a between partition wall edge 24a and the horizontal sealing region 62, and was divided in the gap 65 between the partition wall 24.Subsequently, dry air flows through gap 65, flows through the gap 63b between partition wall edge 24b and the horizontal sealing region 62, and is drawn out of from pore 21b.

In example shown in Figure 8, the width of each gap 63a and 63b is greater than gap 64a between vertical sealing region 61 and the adjacent partition wall 24 and the width (promptly satisfy D1, D2＞d1, d2, D1, D2, d1 and d2 represent the minimum widith of gap 63a, 63b, 64a and 64b respectively here) of 64b.

Adopt this structure, for the dry air of supplying with by pore 21a, the resistance that flows in the gap 65 of gas between partition wall 24 becomes than medium and small at gap 64a and 64b.As a result, compare with 64b with gap 64a, more dry air flows through gap 63a and 63b, thereby makes dry air stably be diverted in the gap 65, and makes dry gas stably flow in gap 65.

According to above-mentioned design, the gas that produces in each gap 65 is extracted out effectively, and this has strengthened the bad effect of fluorescence qualitative change in the bonding process that prevents afterwards.

What it may also be pointed out that is, the minimum widith D1 of gap 63a and 63b and D2 be set to the minimum widith d1 of ratio gap 64a and 64b and d2 is big must be many more, for example be twice or three times, the resistance that flows in the gap 65 of gas between partition wall 24 becomes more little so, dry air also just stably flows through each gap 65 more, and strengthens this bad effect of fluorescence qualitative change in the bonding process afterwards that prevents more.

In example shown in Figure 9, the core of vertical sealing region 61 is connected to adjacent partition wall 24.Therefore, in the center, minimum widith d1 and the d2 of gap 64a and 64b are 0.In this case, dry air more stably flows through each gap 65, because dry air can not flow through gap 64a and 64b.

In the example shown in Figure 10-16, be formed with the prevention wall 70 that flows in the inboard in seal glass zone 60, seal glass zone 60 stops wall 70 closely to contact with flowing.Flow and stop wall 70 to comprise: a pair of vertical wall 71, they extend along vertical sealing region 61; With a pair of horizontal wall 72, they extend along horizontal sealing region 62. Pore 21a and 21b are at the inboard wall 70 that stops near flowing.Should be pointed out that and in example shown in Figure 12, only formed horizontal wall 72.

Flow to stop wall 70 by making, and have the shape identical with partition wall 24 with partition wall 24 identical materials.Therefore, they can be made in same process.

60 when softening because of heating in the seal glass zone, and flowing stops wall 70 to stop the seal glass in seal glass zones 60 to flow into the viewing area that is arranged in face plate center.

Just as shown in Figure 8, in example shown in Figure 10, therefore the width of each gap 63a and 63b provides the effect identical with situation shown in Fig. 8 greater than each gap 64a between vertical sealing region 61 and the adjacent partition wall 24 and the width (satisfying D1, D2＞d1, d2) of 64b.

In example shown in Figure 11, gap 64a between vertical wall 71 and adjacent partition wall 24 and the center of 64b are formed with partition wall 73a and 73b respectively.As the situation shown in Fig. 9, be 0 at minimum widith d1 and the d2 of gap, center 64a and 64b.Therefore, this situation also provides the effect identical with situation shown in Fig. 9.

In example shown in Figure 12, the core of vertical sealing region 61 is connected to adjacent partition wall 24.As the situation shown in Fig. 9, be 0 at minimum widith d1 and the d2 of gap, center 64a and 64b.Therefore, this situation also provides the effect identical with situation shown in Fig. 9.

In example shown in Figure 13, gap 64a between vertical wall 71 and adjacent partition wall 24 and the center of 64b rather than be formed with pore 21a and 21b at diagonal position.In addition, the edge at gap 64a and 64b is formed with partition wall 73a and 73b respectively.Therefore, this situation provides the effect identical with situation shown in Figure 11.

In example shown in Figure 14, be formed with two pore 21a and two pore 21b, and in the middle of partition wall 24, be formed with a central compartment wall 27 as gas vent as the gas access, extension is connected to horizontal wall 72 to partition wall 27 at two ends.In others, this panel almost is identical with the panel shown in Figure 11.In this case, dry air flows in each zone of being separated by central compartment wall 27.But, because the width of each gap 63a and 63b is greater than the width of each gap 64a and 64b, this situation also provides the effect identical with situation shown in Figure 11.In addition, in example shown in Figure 14, can correspond respectively to the flow velocity that dry air is adjusted in each zone of being separated by central compartment wall 27.

The mapping mode of present embodiment

In the present embodiment, as in embodiment 1, the partial pressure of wishing steam be 15 torrs or lower (perhaps, the dew point temperature of dry air is 20 ℃ or lower), and the replacement dry air makes not flowing through also with the low inert gas of phosphor layer reaction and its partial pressure such as nitrogen can obtain identical effect.

Present embodiment has been described the situation that forms partition wall on the plate in the back.But, can form partition wall on the plate in front, and obtain identical effect by identical mode.

Example 2

＜table 2 〉

Table 2

The display panel characteristics of luminescence
						The display panel numbering	Display panel brightness (cd/m 2)	Colour temperature (k) when the whole unit from display panel are luminous	The peak strength of the spectrum of blue light and green glow is than (blue/green)	Adopt TDS to analyze under 200 ℃ or higher temperature H from the blue fluorescent substance desorb 2The maximum quantity of molecule in the O gas	The axial length of blue fluorescent substance crystal is than (c-axle/a-axle)
6 7 8	540 500 470	8400 7200 6300	0.94 0.83 0.76	6.3×10 15 8.8×10 15 2.6×10 16	4.02175 4.02177 4.02208

Display panel 6 is that wherein, in the dry air that flows in bonding process, the partial pressure of steam is set to 2 torrs (dew point temperature of dry air is set at-10) according to a PDP of Figure 10 manufacturing of present embodiment.

Display panel 7 is part PDP according to Figure 15 manufacturing of present embodiment, and wherein, the width of each gap 63a and 63b is less than each gap 64a between vertical sealing region 61 and the adjacent partition wall 24 and the width (satisfying D1, D2＜d1, d2) of 64b.In others, this display panel is made according to Figure 10.When making this display panel 7, panel is to bond together according to the condition identical with display panel 6.

Display panel 8 is PDP that make for relatively.As shown in Figure 16, display panel 8 has a pore 21a on the plate 20 in the back.In bonding process, front panel 10 and rear board 20 are heated and bond together, and dry air is no longer mobile after they are installed together.

Except bonding process, display panel 6-8 makes under the same conditions.Except the pore and the prevention wall that flows, display panel 6-8 has identical panel structure.In in PDP6-8 each, the thickness of phosphor layer is 20 μ m, and the filling pressure of discharge gas Ne (95%)-Xe (5%) is 500 torrs.

Characteristics of luminescence test

For among the PDP 6-8 each, as the characteristics of luminescence, display panel brightness when having measured under not having the situation of colour correction white balance and colour temperature and from the spectrum of blue cell emission with from the ratio of the peak strength of the spectrum of green cell emission.

The result of this test is presented in the table 2.

Each PDP of manufacturing is taken apart, and use the krypton Excimer lamp that the blue fluorescent substance layer of rear board is carried out vacuum ultraviolet (centre wavelength is 146nm) irradiation.Colour temperature when subsequently, measuring light is from all indigo plants, the emission of red and green cell and from the spectrum of blue cell emission with from the ratio of the peak strength of the spectrum of green cell emission.The result is identical with above-mentioned result.

Then, take out blue fluorescent substance from panel.Adopt the TDS analytic approach, measure a gram H of desorb from blue fluorescent substance ₂The molecular number that comprises in the O gas.In addition, by X-ray analysis, measure the c shaft length of blue fluorescent substance crystal and the ratio of a shaft length.The result is also shown in the table 2.

Analyze

Result by shown in the analytical table 2 can draw: in three kinds of display panels, the display panel 6 of present embodiment presents the best characteristics of luminescence.The characteristics of luminescence of display panel 6 is better than display panel 7.This can be understood as and is based on following reason: in the bonding process of display panel 6, dry air stably flows through the gap between the partition wall and the gas that produced is extracted out effectively, and in the bonding process of display panel 7, almost the whole dry airs that import by pore 21a all are discharged to outside after by gap 63a and 63b via pore 21b; And in the situation of display panel 7, owing to have only a spot of dry gas to flow through gap 65 between the partition wall, the gas that produces in the gap 65 can not be extracted out effectively.

The characteristics of luminescence of display panel 8 is poorer than other display panel.This also can be understood as and is based on following reason: the gas that produces in the gap 65 can not be extracted out effectively, because have only a spot of dry gas to flow through gap 65 between the partition wall.

PDP in this example makes according to Figure 10.But, confirmed already: the PDP that makes according to Figure 10-16 presents similar good luminous characteristic.

＜embodiment 3 〉

The PDP of present embodiment has the PDP identical construction with embodiment 1.

Except following difference, the manufacture method of PDP also is identical with embodiment 1: in bonding process, when front panel 10 and rear board 20 bonded together, panel was heated, simultaneously, dry air is to be lower than atmospheric pressure and mobile by the pressure in the inner space is adjusted into.

In the present embodiment, at first, the seal glass material is applied on one of front panel 10 and rear board 20 or both.Temporarily cure the seal glass material that is applied.Subsequently, front panel 10 and rear board 20 are fitted together and are placed in the heating furnace 51 of sealing-in firing equipment 50. Conduit 52a and 52b are connected to glass tube 26a and 26b respectively.Adopt vacuum pump 54,, the pressure in the inner space between the panel is reduced by deflating the space of conduit 52b between panel.Simultaneously, from source of the gas 53 dry air is transported to the inner space by certain flow velocity by conduit 52a.At this moment, the pressure that is adjusted to the inner space of adjuster valve 55a and 55b keeps below atmospheric pressure.

As mentioned above, dry air is supplied to inner space between the panel with low pressure when, (maximum temperature is 450 ℃) heated 30 minutes front panel 10 and rear board 20 under sealing temperature, seal glass layer 15 is softening, so panel 10 and 20 is bonded together by softening seal glass.

The panel of bonding is cured (curing 3 hours) under 350 ℃ of temperature, deflate the inner space between panel simultaneously, to form vacuum.Subsequently, the discharge gas of mentioned component is filled in this space by certain pressure, thereby has made this PDP.

The effect of present embodiment

In the bonding process of present embodiment, in embodiment 1, in the inner space between dry gas inflow panel, panel bonds together.Therefore, as mentioned above, because of contact bad inhibition of change of the fluorescent material that causes with steam.

In embodiment 1, the partial pressure of wishing steam in the dry air is 15 torrs or lower.When the partial pressure of steam is set to lower value, for example 10 torrs or lower, 5 torrs or lower, 1 torr or lower, 0.1 torr or when lower, the performance that suppresses fluorescent material becomes bad effect and becomes more remarkable.The dew point temperature of wishing dry gas is set at 20 ℃ or lower, and wishes that more this temperature is set at lower value, for example 0 ℃ or lower ,-20 ℃ or lower ,-40 ℃ or lower.

In addition, in the present embodiment, the pressure of inner space is held and is lower than atmospheric pressure when bonding together owing to panel, therefore, compares with embodiment 1, and the steam that produces in the inner space more effectively is retracted to the outside.Because the pressure of inner space was held and is lower than atmospheric pressure when dry air was supplied to the inner space, therefore the panel 10 of bonding closely contacts with 20, and reason is that can not expand in the inner space between the panel in bonding process.

The pressure of inner space is low more, and the partial pressure of steam is easy more to be turned down.It is desirable that panel is bonded to tight contact condition.Therefore, wish the pressure of the inner space between the panel is set at 500 torrs or lower, and preferably be set at 300 torrs or lower.

On the other hand, when dry gas being supplied to inner space between the panel and its pressure when very low, the partial pressure step-down of oxygen in the ambient gas.For this reason, when heating in the atmosphere in anaerobic, oxide fluorescent substance is such as the BaMgAl that is usually used in PDP ₁₀O ₁₇: Eu, Zn ₂SiO ₄: Mn and Y ₂O ₃: Eu can produce defective, i.e. oxygen defect.This may cause luminous efficiency to reduce.Therefore, from this angle, wish the pressure of inner space is set at 300 torrs or higher.

The mapping mode of present embodiment

In an embodiment, in bonding process, dry air is supplied to inner space between the panel as protective gas.But, replace dry air, make not flowing through such as nitrogen, can obtain identical effect with phosphor layer reaction and the strong low inert gas of its vapor partial pressure.Here should be pointed out that and wish to supply with the protective gas that comprises oxygen, so that suppress the reduction of brightness.

In the present embodiment, even too low so that when seal glass was softened, the pressure of inner space also was low in temperature.But, in this case, gas can flow into the inner space from heating furnace 51 by the gap between front panel 10 and the rear board 20.Therefore, wish dry air is supplied with or charged in the heating furnace 51.

Perhaps, in order to prevent that gas is from heating furnace 51 flow into inner space between the panel, when still lower and seal glass is softening as yet when temperature, can by not internally the space extract dry gas out and keep the pressure of inner space near atmospheric pressure, subsequently, be elevated to a certain degree or after higher in temperature, the space forces to extract dry gas out internally, is reduced to the pressure with the inner space to be lower than atmospheric pressure.In this case, the hope temperature that will force to extract out dry gas is set at temperature that seal glass begins to soften or higher.In view of the above, the temperature that preferably will force to extract dry gas out is set at 300 ℃ or higher, and more preferably is set at 350 ℃ or higher, preferably is set at 400 ℃ or higher.

Present embodiment has been described such situation: in bonding process, supply with dry air with low pressure to the inner space at panel 10 and 20 heated whiles.But, the technology of curing the technology of fluorescent material or temporarily curing the seal glass material also can be carried out in the atmosphere of supplying with dry air with low pressure.This can provide similar effect.

The panel structure of describing among the embodiment 2 is applied to can produce further effect in the present embodiment.

Example 3

＜table 3 〉

The table 3. display panel bonding condition and the characteristics of luminescence

The display panel numbering	The dry gas type	The partial pressure of steam (torr) in the dry gas	The pressure in the space between the panel (torr)	Be reduced to temperature when being lower than atmospheric pressure (℃)	The relative luminous intensity of blue light	The chromaticity coordinate Y of blue light	The peak wavelength of blue light (nm)	Colour temperature during white balance (K)	The peak strength of the spectrum of blue light and green glow is than (blue/green)	Adopt TDS to analyze under 200 ℃ or higher temperature H from the blue fluorescent substance desorb 2The maximum quantity of molecule in the O gas	The axial length of blue fluorescent substance crystal is than (c-axle/a-axle)
												11 12 13 14 15 16 17 18 19 20 21 22 23	Air air air air air air air air air nitrogen N e-Xe (%) air-	12 8 3 0 0 0 0 0 0 0 0 0 -	500 500 500 500 300 100 500 500 500 500 500 atmospheric pressure atmospheric pressures	370 370 370 370 370 370 room temperatures 320 420 370 370--	108 115 120 125 120 113 121 123 127 105 105 125 100	0.075 0.068 0.063 0.058 0.058 0.058 0.062 0.060 0.056 0.058 0.058 0.058 0.090	455 454 453 451 451 451 452 452 450 451 451 451 458	7100 7600 7900 8700 8600 8500 8000 8200 9000 8400 8400 8700 5800	0.82 0.88 0.91 0.96 0.96 0.95 0.92 0.93 0.98 0.94 0.94 0.96 0.67	1.0×10 16 7.9×10 15 7.1×10 15 5.9×10 15 5.9×10 15 5.3×10 15 6.4×10 15 6.0×10 15 2.2×10 15 4.8×10 15 4.8×10 15 5.9×10 15 2.6×10 16	4.02180 4.02177 4.02176 4.02174 4.02174 4.02172 4.02176 4.02175 4.02164 4.02173 4.02173 4.02174 4.02208

Table 3 demonstrates the multiple display panel bonding condition corresponding to each PDP, and these PDP comprise the PDP and the PDP that is used for comparison according to present embodiment.

Display panel 11-21 is the PDP that makes according to present embodiment.Display panel 11-21 makes under different condition, and these conditions comprise: flow between the panel partial pressure of steam in the dry gas in the inner space in bonding process; Pressure in the inner space between the panel; The pressure of inner space begins to be reduced to the temperature when being lower than atmospheric pressure; And the type of dry gas.

Display panel 22 is the PDP that make according to embodiment 1, and wherein, dry gas is supplied to the inner space, but does not force gas bleeding from this space in bonding process.

Display panel 23 is the PDP that make for relatively.Display panel 23 is made according to conventional methods, and wherein dry air is not supplied with in the inner space between panel.

In in PDP 11-23 each, the thickness of phosphor layer is 30 μ m, and the filling pressure of discharge gas Ne (95%)-Xe (5%) is 500 torrs.

Characteristics of luminescence test

For among the PDP 11-23 each, measured following characteristic: the peak wavelength of the chromaticity coordinate y of the relative luminous intensity of the blue light of being launched, the blue light of being launched, the blue light of being launched, the colour temperature when not having under the colour correction situation and from the spectrum of blue cell emission and ratio from the peak strength of the spectrum of green cell emission in white balance as the characteristics of luminescence.

In above-mentioned characteristic, the relative luminous intensity of blue light, the chromaticity coordinate y of blue light and colour temperature when not having under the colour correction situation in white balance are to adopt the method measurement identical with embodiment 1.The peak wavelength of the blue light of being launched is to measure like this: the spectrum that only shines the blue light that blue cell and measurement launch.The result of this test is presented in the table 3.

The relative luminous intensity value that should be pointed out that the blue light shown in the table 3 is the relative value when the luminous intensity of the display panel of measuring as a comparative example 23 is set to standard value 100.

Each PDP of manufacturing is taken apart, and use the krypton Excimer lamp that the blue fluorescent substance layer of rear board is carried out the vacuum ultraviolet irradiation.Colour temperature when subsequently, the chromaticity coordinate y, light that measures blue light is from whole indigo plants, red and green cell emission and from the spectrum of blue cell emission with from the ratio of the peak strength of the spectrum of green cell emission.The result is identical with above-mentioned result.

Then, take out blue fluorescent substance from panel.Adopt the TDS analytic approach, measure a gram H of desorb from blue fluorescent substance ₂The molecular number that comprises in the O gas.In addition, by X-ray analysis, measure the c shaft length of blue fluorescent substance crystal and the ratio of a shaft length.The result is also shown in the table 3.

Analyze

Result by shown in the analytical table 3 can draw: the characteristics of luminescence of the display panel 11-21 of present embodiment is better than comparative example (display panel 23) (showing as the colour temperature when having higher blue light luminous intensity and higher white balance).

For the characteristics of luminescence, display panel 14-22 has identical value.This shows: if the partial pressure of steam is identical in the dry air that flows in the inner space, no matter the pressure in the inner space equals atmospheric pressure or is lower than atmospheric pressure, and the effect that obtains (characteristics of luminescence) all is identical.

But, in the sample of display panel 22, find that sample segment has the gap between partition wall and front panel.This can be regarded as and is based on following reason: in bonding process, because the dry gas of supplying with causes the inner space that expansion is arranged slightly.

By comparing the characteristics of luminescence of display panel 11-14, can notice: the order that the luminous intensity of blue light is pressed display panel 11,12,13,14 increases, and the chromaticity coordinate y of the blue light of being launched reduces in this order.This shows: along with the reduction of the partial pressure of steam in the dry air, the luminous intensity of the blue light of being launched increases, and the chromaticity coordinate y of the blue light of being launched reduces.This can be regarded as and is based on following reason: by reducing the partial pressure of steam, prevented that the change of blue fluorescent substance is bad.

By comparing the characteristics of luminescence of display panel 14-16, can notice: for the chromaticity coordinate y of the blue light of being launched, these display panels have identical value.This shows: the chromaticity coordinate y of the blue light of being launched is not subjected to the influence of the pressure of the inner space between the panel.Also it may be noted that of the order reduction of the relative luminous intensity of blue light by display panel 14,15,16.This shows: along with the partial pressure of oxygen in the protective gas reduces, and in fluorescent material, produced defective, be oxygen defect, the luminous intensity of the blue light of being launched reduces.

By comparing the characteristics of luminescence of display panel 14,20 and 21, can notice: for the chromaticity coordinate y of the blue light of being launched, these display panels have identical value.This shows: the chromaticity coordinate y of the blue light of being launched is not flowed into the influence of the type of the dry gas in the inner space between the panel.The relative luminous intensity that also it may be noted that the blue light of display panel 20 and 21 is lower than display panel 14.This shows: adopting when not wrapping oxygen containing nitrogen or Ne (95%)-Xe (5%) gas of etc.ing as dry gas because in fluorescent material, produced defective, be oxygen defect, the luminous intensity reduction of the blue light of being launched.

By comparing the characteristics of luminescence of display panel 14 and 17-19, can notice: the order that the luminous intensity of blue light is pressed display panel 17,18,14,19 increases, and the chromaticity coordinate y of the blue light of being launched reduces in this order.This shows: the temperature when beginning space gas bleeding internally for the pressure that makes the inner space is brought down below atmospheric pressure is set to higher temperature, the luminous intensity of the blue light of being launched increases, and the chromaticity coordinate y of the blue light of being launched reduces.This can be regarded as and be based on following reason: the beginning temperature of will bleeding is set at higher temperature, has prevented that protective gas around the panel from flowing in the inner space between the panel.

Focus onto each listed in the table 3 display panel launch blue light chromaticity coordinate y and launch relation between the peak wavelength of blue light, can notice that along with chromaticity coordinate y reduces, peak wavelength shortens.This shows between them it is directly proportional relation.

＜embodiment 4 〉

The PDP of present embodiment has 1 identical construction with embodiment.

Till bonding process (that is, in bonding process, the front panel 10 and the rear board 20 that are fitted together are heated, and do not supply with dry air to the inner space between the panel simultaneously), the manufacture method of PDP is identical with conventional method.But, in air aspiration process, be drawn out of and form vacuum (evacuation process) before at gas, the heating panel, dry gas is supplied with in the inner space between the panel (following this technology is also referred to as dry gas technology) simultaneously.This can make the characteristics of luminescence of blue fluorescent substance layer return to them by bonding process or the former bad level before of technology change.

The air aspiration process of present embodiment will be described below.

In the air aspiration process of present embodiment, adopt the sealing-in firing equipment shown in Fig. 4, and followingly describe with reference to Fig. 4.

In advance glass tube 26a and 26b are connected to respectively on the pore 21a and 21b of rear board 20. Conduit 52a and 52b are connected to glass tube 26a and 26b respectively.Use vacuum pump 54, by conduit 52b, from the inner space gas bleeding between the panel, temporarily the inner space is vacuumized.Subsequently, under the situation of not using vacuum pump 54, by certain flow velocity dry air is supplied with the inner space by conduit 52a.This makes flow through inner space between panel 10 and 20 of dry air.By conduit 52b, dry air is discharged from.

When dry air is supplied with the inner space, panel 10 and 20 is heated to uniform temperature.

Subsequently, stop to supply with dry air.After this, use vacuum pump 54, deflate, simultaneously temperature is remained on certain degree, to extract the gas that in the inner space, is detained out by absorption from the inner space between the panel.

After the air aspiration process, discharge gas is charged in each unit, after this PDP has just finished.

The effect of present embodiment

The air aspiration process of present embodiment has and prevents that in this technology phosphor layer from becoming bad effect.

Air aspiration process also has the characteristics of luminescence that makes phosphor layer (especially blue fluorescent substance layer) and returns to them by the bad level before of technology change formerly.Phosphor layer (especially blue fluorescent substance layer) is subjected to the influence of heating easily and becomes bad in phosphor layer baking process, temporary transient baking process and bonding process.If phosphor layer becomes bad in above-mentioned technology, the air aspiration process of present embodiment just can make their characteristics of luminescence recover.

Above-mentioned effect is considered to based on following reason.

In bonding process, when the panel that bonds together is heated, discharge gas (especially steam) in the inner space between panel.For example, when the panel of bonding was placed in the air, water was trapped in the inner space by absorption.Therefore, when panel is heated in this state, just discharge steam in the space between panel.According to the air aspiration process of present embodiment, this steam is retracted to the outside effectively because before evacuation process begins the heated while of panel, dry gas flows through the inner space.Therefore, with just gas bleeding and the conventional air aspiration process of not supplying with dry gas is compared simply, the fluorescence qualitative change that causes because of heating in the air aspiration process of present embodiment is bad to be very faint.

Can also understand like this: taken place and the bad opposite reaction of the change that causes because of heating owing to use the air aspiration process of dry gas to make, so the characteristics of luminescence is recovered.

Can clearly be seen that from the above description: present embodiment provides extraordinary effect, that is, in air aspiration process as last heating process, the becoming the bad characteristics of luminescence and can recover of blue fluorescent substance.

In order to strengthen the recovery effects of the bad characteristics of luminescence of becoming of blue fluorescent substance, hope can meet the following conditions.

Peak temperature in the air aspiration process high more (that is: the temperature when temperature that counter plate heats when supplying with dry gas and gas bleeding form vacuum is high more), the recovery effects that has become the bad characteristics of luminescence is big more.

In order to obtain this effect fully, preferably peak temperature is set at 300 ℃ or higher, and further is preferably set to higher temperature, for example 360 ℃ or higher, 380 ℃ or higher and 400 ℃ or higher.But, temperature should not be set at high to making the softening temperature that flows of seal glass.

The temperature that counter plate heats when also preferably will supply with dry gas is set at the temperature that is higher than when vacuumizing.This is because when temperature is set by opposite way, and the gas (especially steam) that is discharged into the inner space from panel in evacuation process has weakened this effect; And when temperature is set in a manner described, just can reach this effect, because compare with the previous case, the gas that is discharged into the inner space from panel in evacuation process is less.

Preferably the partial pressure with steam in the dry gas of being supplied with is set at alap value.This is because of the partial pressure step-down along with steam in the dry gas, the recovery effects that becomes the bad characteristics of luminescence of blue fluorescent substance strengthens, though compare with the evacuation process of routine, when the partial pressure of steam is 15 torrs or when lower, this effect is exactly very significant.

Below test also shows: the bad characteristics of luminescence that becomes of recovering blue fluorescent substance is possible.

Figure 17 and 18 demonstrates the relation between the partial pressure of the recovery effects of the characteristics of luminescence that becomes bad and steam, wherein blue fluorescent substance layer (BaMgAl ₁₀O ₁₇: Eu) become bad and in air, cured once more subsequently.Method of measurement is as described below.

Partial pressure at steam is the air baking blue fluorescent substance (chromaticity coordinate y is 0.052) (curing 20 minutes 450 ℃ of peak temperatures) of 30 torrs, and blue fluorescent substance becomes bad because of heating.In the bad blue fluorescent substance of change, chromaticity coordinate y is 0.092, and relative luminous intensity (value that the luminous intensity of the blue fluorescent substance of measuring before will curing obtains when being set at standard value 100) is 85.

Under certain peak temperature (350 ℃ and 450 ℃ were kept 30 minutes), in having the strong air of different vapor partial pressures, cure the blue fluorescent substance that becomes bad once more.Then, measure the relative luminous intensity and the chromaticity coordinate y of the blue fluorescent substance that cures once more.

Figure 17 demonstrate airborne vapor partial pressure when curing once more strong with the relative luminous intensity that cures the back measurement once more between relation.Figure 18 demonstrate airborne vapor partial pressure when curing once more strong with the chromaticity coordinate y that cures the back measurement once more between relation.

Can notice from Figure 17 and 18: no matter once more stoving temperature is 350 ℃ or 450 ℃, when airborne vapor partial pressure is by force in 0-30 torr scope when curing once more, the relative luminous intensity of blue light all is high, and the chromaticity coordinate y of blue light is little.This shows: become bad even cure fluorescent material and the characteristics of luminescence in comprising the atmosphere of a large amount of steam, when curing fluorescent material once more in the strong low atmosphere of vapor partial pressure, the characteristics of luminescence still can be recovered.That is, these results show the change of the blue fluorescent substance that causes because of heating bad be a kind of reversible reaction.

From Figure 17 and 18, it is further noted that: when curing once more in the air vapor partial pressure strong reduce or once more stoving temperature improve, the recovery effects that has become the bad characteristics of luminescence strengthens.

Different cycles corresponding to peak temperature is kept has carried out similar measurement, although this is not elaborated here.The result shows: the cycle lengthening of keeping along with peak temperature, the recovery effects that has become the bad characteristics of luminescence strengthens.

The variation pattern of present embodiment

In the present embodiment, when heating panel in air aspiration process, used dry air.But, replace dry air, also can use, and can obtain identical effect such as inactive gass such as nitrogen or argon gas.

In the air aspiration process of present embodiment, before beginning to vacuumize, heating panel when dry air is supplied in the space between the panel.But, be higher than conventional temperature (promptly being set at 360 ℃ or higher), only carry out evacuation process and can make the characteristics of luminescence of fluorescent material return to certain degree by the temperature in the evacuation process is set at.In addition, in this case, extraction temperature is high more, and characteristics of luminescence recovery effects is good more.

But the air aspiration process of present embodiment has better characteristics of luminescence recovery effects than above-mentioned mapping mode.This can be understood that to be based on following reason: under the situation of above-mentioned mapping mode, in evacuation process, abundant steam is not retracted to outside the panel, because the inner space between the panel is very little.

Can expect: when heating panel when supplying with dry gas, the panel structure of describing among the embodiment 2 is used for the effect that present embodiment is bled enhancing.

Example 4

＜table 4 〉

Table 4

Display panel vacuumizes the condition and the characteristics of luminescence (blue light)
						The display panel numbering	Heating-up temperature during dry air is supplied with (℃) (keeping 30 minutes)	Heating-up temperature during vacuumizing (℃) (keeping 2 hours)	The partial pressure of steam (torr) in the dry air	The relative luminous intensity of blue light	The chromaticity coordinate Y of blue light
21 22 23 24 25 26 27 28 29 30 31 32 33	350 360 390 410 410 350 410 410 410 - - - -	350 350 350 350 410 410 350 350 350 360 390 410 350	2 2 2 2 2 2 12 8 0 - - - -	107 110 118 125 121 105 112 116 128 103 107 110 100	0.062 0.061 0.056 0.053 0.056 0.065 0.070 0.067 0.052 0.085 0.081 0.076 0.090

Display panel 21-29 is the PDP that makes according to present embodiment.Display panel 21-29 makes under the different heating when the heating panel or the extraction temperature when supplying with dry gas to the inner space.In this manufacturing process, when dry gas is supplied with in the inner space, certain heating-up temperature was kept 30 minutes, in the evacuation process below, certain extraction temperature was kept 2 hours subsequently.

Display panel 30-32 is the PDP that makes according to the mapping mode of present embodiment.Display panel 30-32 is under the situation that does not have dry gas technology, carries out under 360 ℃ or higher temperature that evacuation process makes.

Display panel 33 is the PDP that make according to conventional methods.Display panel 33 is under the situation that does not have dry gas technology, and the evacuation process that carried out under 350 ℃ of temperature 2 hours is made.

In in PDP 21-33 each, the thickness of phosphor layer is 30 μ m, and the filling pressure of discharge gas Ne (95%)-Xe (5%) is 500 torrs.

Characteristics of luminescence test

For among the PDP 21-33 each, the relative luminous intensity of blue light and the chromaticity coordinate y of blue light have been measured as the characteristics of luminescence.

＜test result and analysis 〉

The result of this test is presented in the table 4.The relative luminous intensity value that should be pointed out that the blue light shown in the table 4 is the relative value when the luminous intensity of the display panel of measuring as a comparative example 33 is set to standard value 100.

Can notice from table 4: compare with display panel 33, each among the display panel 21-28 all has higher luminous intensity and less chromaticity coordinate y.This shows: the air aspiration process of employing present embodiment has been improved the characteristics of luminescence of PDP when making PDP.

By comparing the characteristics of luminescence of display panel 21-24, can notice: the order that the characteristics of luminescence is pressed display panel 21,22,23 and 24 improves (luminous intensity increases, and chromaticity coordinate y reduces).This shows: the heating-up temperature of dry gas technology is set highly more, and the characteristics of luminescence recovery effects of blue fluorescent substance layer is big more.

By comparing the characteristics of luminescence of display panel 24-26, can notice: the order that the characteristics of luminescence is pressed display panel 26,25 and 24 improves.This shows: the heating-up temperature of dry gas technology is set highlyer more than the extraction temperature of evacuation process, and the characteristics of luminescence recovery effects of blue fluorescent substance layer is big more.

By comparing the characteristics of luminescence of display panel 24 and 27-29, can notice: the order that the characteristics of luminescence is pressed display panel 27,28,24 and 29 improves.This shows: the vapor partial pressure of dry gas technology is set more for a short time by force, and the characteristics of luminescence recovery effects of blue fluorescent substance layer is big more.

Compare with display panel 33, each among the display panel 30-32 all has higher luminous intensity and less chromaticity coordinate y.This shows: the air aspiration process of employing present embodiment mapping mode has been improved the characteristics of luminescence of PDP when making PDP.

Compare with display panel 21, each among the display panel 30-32 all has the lower characteristics of luminescence.This shows: when adopting the dry gas technology of present embodiment, the recovery effects of the characteristics of luminescence of blue fluorescent substance layer is bigger.

＜embodiment 5 〉

The PDP of present embodiment has 1 identical construction with embodiment.

Till temporary transient baking process, the PDP manufacture method of present embodiment is identical with embodiment 1.But, in bonding process, preheat panel when between the opposite flank of panel, leaving the space, subsequently heated panel is put together and bonds together.

In the PDP of present embodiment, when light only when blue cell is launched, from the chromaticity coordinate y of the light of blue cell emission is 0.08 or littler, and the peak wavelength of light emitted spectrum is 455nm or shorter, and the colour temperature when not having under the colour correction situation in white balance is 7000K or higher.In addition, be made as 0.06 or littler,, can make the colour temperature when not having under the colour correction situation bring up to about 11000K in white balance according to creating conditions by chromaticity coordinate y with blue light.

To explain the bonding process of present embodiment now.

Figure 19 demonstrates the structure of the stamping device that uses in the bonding process.

Stamping device 80 comprises: a heating furnace 81 is used to heat front panel 10 and rear board 20; A steam supply valve 82 is used to regulate the protective gas amount that is supplied to heating furnace 81; A vent valve 83 is used to regulate the gas flow of extracting out from heating furnace 81.

By the heater (not shown), the inside of heating furnace 81 can be heated to high temperature.By steam supply valve 82, protective gas (for example dry air) can be supplied with heating furnace 81, protective gas has formed the atmosphere that heats panel therein.Adopt the vacuum pump (not shown),, gas can be extracted out from heating furnace 81, thereby in heating furnace 81, be formed vacuum by vent valve 83.By steam supply valve 82 and vent valve 83, can regulate the vacuum degree in the heating furnace 81.

In the middle of heating furnace 81 and protective gas supply source, be provided with a drier (not shown).Drier makes protective gas cooling (to negative tens degree), so that by making water condensation in the gas remove water in the protective gas.Protective gas is admitted to heating furnace 81 by drier, has so just reduced the quantity of steam in the protective gas (vapor partial pressure is strong).

In heating furnace 81, be formed with a base 84.Front panel 10 and rear board 20 on base 84, have been placed.On base 84, be formed with slipping column 85, be used to make rear board 20 to move to each position parallel with self.Above base 84, be formed with dipper crowding gear 86, be used for pushing rear board 20 downwards.

Figure 20 is the in-built stereogram that shows heating furnace 81.

In Figure 19 and 20, rear surface 20 is to place like this: make the length of partition wall be represented as horizontal line.

As shown in Figure 19 and 20, the length of rear board 20 is greater than the length of front panel 10, and the both sides of the edge of rear board 20 extend beyond front panel 10.The extension that should be pointed out that rear board 20 is provided with lead-in wire, and these lead-in wires are connected to drive circuit with address electrode 22.Slipping column 85 and dipper crowding gear 86 are arranged on four bights of rear board 20, are inserting and putting the extension of rear board 20 between them.

Four slipping columns 85 stretch out from base 84, and can move up and down simultaneously by a pillar elevating mechanism (not shown).

In four dipper crowding gears 86 each comprises: the strutting piece 86a of a tubular, and it is fixed on the roof of heating furnace 81; A sliding bar 86b, it can move up and down in strutting piece 86a; With a spring 86c, its sliding bar 86b in strutting piece 86a applies downward pressure.By exerting pressure to sliding bar 86b, rear board 20 is pushed downwards by sliding bar 86b.

Figure 21 A-21C demonstrates the operation of stamping device in preheating technology and bonding process.

Describe temporary transient baking process, preheat technology and bonding process with reference to Figure 21 A-21C below.

Temporary transient baking process

The slurry coating that seal glass (frit) is made is descending on one of column region: the perimeter facing to rear board 20 1 sides of front panel 10; The perimeter facing to front panel 10 1 sides of rear board 20; And the perimeter of the opposed facing side of front panel 10 and rear board 20.The panel that will have slurry temporarily cured 10-30 minute at about 350 ℃, to form seal glass layer 15.It may be noted that in the drawings seal glass layer 15 is formed on the front panel 10.

Preheat technology

At first, after appropriate location, front panel 10 and rear board 20 are put together.Subsequently, a fixed position that panel is placed on the base 84 is located.Then dipper crowding gear 86 is arranged to push rear board 20 (Figure 21 A).

Subsequently, protective gas (dry air) is circulated (perhaps, passing through vent valve 83 gas bleedings simultaneously to form vacuum) in heating furnace 81, carry out following operation simultaneously.

Slipping column 85 is risen, thereby make rear board 20 move to a position (Figure 21 B) parallel with self.This makes the space between front panel 10 and the rear board 20 widen, and makes phosphor layer 25 on the rear board 20 be exposed to a big space in the heating furnace 81.

Under above state, heating furnace 81 is heated, so that panel discharges gas.When reaching predetermined temperature (for example 400 ℃), preheat technology and finish.

Bonding process

Slipping column 85 is descended, thereby front and back panel is put together once more.That is, rear board 20 is placed its correct position (Figure 21 C) on plate 10 in front again.

When heating furnace 81 inside have reached the specific sticking temperature (about 450 ℃) of the softening point that is higher than seal glass layer 15, kept sticking temperature 10-20 minute.In this cycle, the perimeter of front panel 10 and rear board 20 is bonded together by softening seal glass.Because in the cycle, rear board 20 is pushed front panel 10 to by dipper crowding gear 86 in this bonding, so panel is realized bonding with high stability.

After bonding was finished, dipper crowding gear 86 was disengaged, and the panel of bonding is removed.

After carrying out bonding process in a manner described, carry out air aspiration process.

In the present embodiment, shown in Figure 19 and 20, a pore 21a is formed on the perimeter of rear board 20.Use is connected to a vacuum pump (not shown) of a glass tube 26 (glass tube 26 is installed on the pore 21a), bleeds.After air aspiration process,, fill discharge gas in the inner space between panel by glass tube 26.After blocked and glass tube 26 was cut off at pore 21a, this PDP had just finished.

The effect of the manufacture method of showing in the present embodiment

The manufacture method of present embodiment has following effect, and these effects can not obtain from conventional method.

As described in the embodiment 1; adopt conventional method; the phosphor layer 25 that contacts with inner space between the panel since heating and be limited in the influence of the gas (in these gases, especially the steam that discharges from protective layer 14) in this space may cause becoming bad.The bad luminous intensity of these layers (especially blue fluorescent substance layer) that makes of the change of phosphor layer reduces.

According to the method for showing in the present embodiment, be released in preheating technology though resemble the such gas of steam that is trapped on the front and back panel by absorption, these gases can not be limited in the inner space, because separated big space between the panel.In addition, bond together owing to panel after preheating is heated immediately, water (steam) etc. can not be trapped on the panel by absorption after preheating.Therefore, have only gas seldom to discharge from panel 10 and 20 in bonding process, this becomes bad with regard to having prevented phosphor layer 25 because of heating.

In addition, in the present embodiment, preheating technology is to carry out in the atmosphere of dry air circulation to bonding process.Therefore, can not cause phosphor layer 25 to become bad owing to the steam that heats and be included in the protective gas.

Another advantage of present embodiment is: owing to preheat technology and bonding process is to carry out continuously in same heating furnace 81, these technologies can be carried out apace, and consumed energy is less.

Moreover, having the stamping device of above-mentioned structure by use, front panel 10 and rear board 20 can be bonded on the position of suitable adjustment.

The analysis of the timing that puts together to pre-heating temperature with panel

Be appreciated that in order to prevent that phosphor layer 25 from becoming bad because of the influence of the heating of bonding during panel and the gas that discharges from panel (these gases, especially the steam that discharges from protective layer 14), wishes panel is heated to high as far as possible temperature.

In order at length to analyze this problem, carried out following test.

Heating the glass substrate (as front panel 10) that is formed with the MgO layer on it gradually with constant firing rate when, use the TDS analytical equipment, with measuring the quantity of steam that discharges on the MgO layer heating time.

The quantity of steam that is discharged that Figure 22 demonstrates result of the test or measures under each heating-up temperature of 700 ℃.

In Figure 22, first peak value appears at about 200 ℃-300 ℃, and second peak value appears at about 450 ℃-500 ℃.

Estimate when heated protective layer 14 gradually, have a large amount of steam to discharge at about 200 ℃-300 ℃ and about 450 ℃-500 ℃ from the result shown in Figure 22.

Therefore; be appreciated that; the steam that discharges from protective layer 14 when preventing in bonding process the heating panel is limited in the inner space, and the separation that should keep panel in the heating panel is increased to about 200 ℃, preferably is increased to about 300 ℃-400 ℃ up to temperature at least.

In addition, panel is bonded together after about 450 ℃ temperature, almost can prevent the release of gas fully from panel if when panel separates, be heated to be higher than.In this case, to prevent that also the All Time wainscot after panel bonding is finished from changing because panel fluorescent material does not almost become bad and have hardly that the steam that is detained by absorption on the panel discharges gradually in discharge process when bonding together may.

But, it is not preferred that this temperature surpasses 520 ℃, because phosphor layer and MgO protective layer normally form under about 520 ℃ stoving temperature.Therefore, further preferred scheme is to bond them together after panel is heated to about 450 ℃-520 ℃.

On the other hand, if be heated the temperature of the softening point that surpasses seal glass when panel separates, seal glass will flow and leave due position.This may hinder panel to realize bonding with high stability.

From preventing that the gas that phosphor layer discharges because of panel from becoming bad viewpoint, and consider and can obtain the high stability bonding of panel with draw a conclusion (1)-(3).

(1) wishes that front and back panel is placed and bonds together after following state, that is: when panel is separated from each other, be heated to high as far as possible temperature under the softening point of used seal glass.

Correspondingly, when for example using softening point to be about 400 ℃ commonly used common seal glass, the ill-effect of fluorescent material is kept simultaneously the stability of bonding in order to alleviate the gas that is discharged as much as possible, the best bond program is: when front and back panel is separated they are heated near 400 ℃, subsequently panel is put together, and they are heated to temperature above softening point, thereby they are bonded together.

(2) here, use the seal glass that has than high softening-point will improve the stability that heating-up temperature also strengthens the bonding panel.Correspondingly, use this high softening-point seal glass, front and back panel is heated near softening point, subsequently panel is put together, and they are heated to temperature above softening point, thereby they are bonded together, and this will further alleviate the ill-effect to fluorescent material of the gas that discharged, keep the stability of panel bonding simultaneously.

(3) on the other hand, even panel is heated to the high temperature above the softening point of seal glass when panel separates, if its adopt following structure also can with the panel high stability bond together, even that is: softening, the seal glass layer before or after being formed on the perimeter of panel can not flow yet and leave the position that should locate.For example, can flow out the arrival viewing area with the seal glass that prevents to soften laying partitioned portion of formation between district and the viewing area at seal glass on the perimeter of front or rear panel.

Correspondingly, adopted this can prevent that the seal glass that softens from flowing out to the structure of viewing area after, when front and back panel is heated to when being placed on and bonding together above the high temperature of the softening point of seal glass and with rear board, can alleviate the gas that discharged to the ill-effect of fluorescent material and keep the stability of panel bonding simultaneously.

In above situation, front and back panel at high temperature directly bonds together, rather than at first puts together then and heat.As a result, almost can prevent from fully after panel puts together, to discharge gas from panel.This makes panel to bond together, and the change that has the fluorescent material that causes because of heating simultaneously hardly is bad.

Analysis to protective gas and pressure

Wish that the oxygen containing gas of bag resemble the air is used as the protective gas that circulates in the bonding process in heating furnace 81.This is because of as described in example 1 above, and when being heated in the atmosphere in anaerobic, the oxide fluorescent substance that is generally used for PDP is tending towards making the characteristics of luminescence to reduce.

When supplying with normal pressure, can obtain effect to a certain degree as the extraneous air of protective gas.But,, wish dry gas, in heating furnace 81, circulate, the formation vacuum of perhaps in heating furnace 81 work, bleeding as dry air in order to strengthen the effect that prevents that the fluorescence qualitative change is bad.

The reason of wishing the dry gas circulation is: so just do not worry that fluorescent material becomes bad because of the steam that comprises in heating and the protective gas.In addition, wish from heating furnace 81, to bleed the formation vacuum.This is because the gas (steam etc.) that heating discharges from panel 10 and 20 time is retracted to the outside effectively.

When dry gas as the protective gas circulation time, the partial pressure of the steam that comprises in the gas is low more, can prevent that more the blue fluorescent substance layer from becoming bad (referring to the result of the test of the embodiment 1 shown in Fig. 5 and 6) because of heating.In order to obtain enough effects, wish the partial pressure of steam is set at 15 torrs or lower.When the partial pressure of steam is set at lower value, for example 10 torrs or lower, 5 torrs or lower, 1 torr or lower, 0.1 torr or when lower, this effect becomes more remarkable.

The coating of seal glass

In bonding process, seal glass normally only was coated in (generally being only to be coated on the rear board) on one of two panels before panel puts together.

Simultaneously, in the present embodiment, by the dipper crowding gear in the stamping device 80 86, rear board 20 is pushed to front panel 10.In this case, be difficult to provide and resemble strong pressure the anchor clamps.

In this case, when seal glass only was coated on the rear board, if the consistency between seal glass and the front panel is not so good for bonding, panel just might not exclusively bond.If the seal glass layer not only is formed on the front panel but also be formed on the rear board, this defective just can prevent.This will improve the rate of finished products of PDP.

Should be pointed out that the said method that the seal glass layer not only is formed on the front panel but also is formed on the rear board can improve rate of finished products effectively for the general bonding process in making the PDP process.

The mapping mode of present embodiment

In the present embodiment, after the appropriate location, front panel 10 and rear board 20 are placed on together before heating.Slipping column 85 rises subsequently, rear board 20 is moved up and panel is separated.But, panel 10 and 20 can be separated from each other by alternate manner.

For example, Figure 23 shows the another kind of mode that the rear board 20 of sening as an envoy to rises.In the figure, front panel 10 is surrounded by a framework 87, and front panel 10 is put into framework 87.Framework 87 can move up and down by bar 88, and bar 88 is fixed to framework 87 and vertical the slip.Adopt this structure, the rear board 20 that is placed on the framework 87 also can move up and down each position parallel with self.That is, when framework 87 moved up, rear board 20 separated with front panel 10, and when framework 87 moved down, rear board 20 put together with front panel 10.

Also has another difference between two kinds of mechanisms.In stamping device 80, rear board 20 is pushed on the front panel 10 by dipper crowding gear 86, and in example shown in Figure 23, replaces dipper crowding gear 86, is placed with a pouring weight 89 in the back on the plate 20.In the method for this conversion, when framework 87 was moved down into the bottom, pouring weight 89 was pressed in rear board 20 on the front panel 10 by gravity.

Figure 24 A-24C demonstrates the operation of carrying out according to the method for another kind of conversion in bonding process.

In the example shown in Figure 24 A-24C, rear board 20 and front panel 10 local detachment, and return to initial position.

On base 84, situation as shown in Figure 20 is such, and four bights corresponding to rear board 20 are formed with four pillars or pair of posts 85a and pair of posts 85b on base 84.But, pillar 85a corresponding to rear board 20 1 sides (left side in Figure 24 A-24C), (for example support rear board 20 in its edge, the spherical edge that forms of pillar 85a is inserted on the panel 20 in the formed spherical pit), and can move up and down corresponding to the pillar 85b of rear board 20 opposite sides (right side in Figure 24 A-24C).

Front panel 10 and rear board 20 put together, and are placed on the base 84, as shown in Figure 24 A.By pillar 85b is moved up, rear board 20 rotates around the edge of pillar 85a, as shown in Figure 24 B.This makes rear board 20 and front panel 10 local detachment.By pillar 85b is moved down, rear board 20 opposite spins also return to initial position, as shown in Figure 24 C.That is, panel 10 and 20 is in and the suitable identical position, position of initial adjustment.

In the state shown in Figure 24 B, panel 10 and 20 side contacts at pillar 85a.But, the gas that discharges from panel can not be limited in the inner space, because the opposite side of panel is open.

Example 5

＜table 5 〉

Table 5

The display panel numbering	The temperature that front and back panel is put together (℃)	The peak temperature of bonding panel (℃)	Atmosphere during bonding	The partial pressure of steam (torr) in the dry air	The relative luminous intensity of blue light	The chromaticity coordinate Y of blue light	Colour temperature during white balance (K)	The chromaticity coordinate Y of blue light when shining the fluorescent material of rear board by Excimer lamp	The peak wavelength of blue light (nm)	When colour temperature (K) by fluorescent material time of all colours of Excimer lamp irradiation rear board	The peak strength of the spectrum of blue light and green glow is than (blue/green)	Adopt TDS to analyze under 200 ℃ or higher temperature H from the blue fluorescent substance desorb 2The maximum quantity of molecule in the O gas	The axial length of blue fluorescent substance crystal is than (c-axle/a-axle)
														41 42 43 44 45 46 47 48 49 50 51 52	250 350 400 400 400 400 400 450 500 450 450 -	450 450 450 450 450 450 450 450 500 480 450 450	Dry air dry air dry air dry air dry air dry air vacuum drying air dry air dry air dry air dry air	2 2 12 8 2 0 - 2 2 2 2 2	107 118 108 112 120 123 120 125 125 126 125 100	0.078 0.057 0.075 0.065 0.055 0.053 0.053 0.052 0.052 0.052 0.052 0.090	6700 8600 7100 7800 9000 9800 9300 10600 10600 11000 10600 5800	0.075 0.054 0.073 0.063 0.054 0.052 0.052 0.051 0.051 0.051 0.051 0.088	455 451 459 452 450 449 449 448 448 448 448 458	6700 8600 7100 7800 9000 9800 9300 10600 10600 11000 10600 5800	0.80 0.95 0.82 0.91 0.98 1.09 1.03 1.15 1.15 1.19 1.15 0.67	1.0×10 16 4.0×10 15 7.3×10 15 5.0×10 15 3.4×10 15 2.2×10 15 1.3×10 15 1.9×10 15 1.9×10 15 1.3×10 15 1.9×10 15 2.6×10 16	4.02180 4.02172 4.02178 4.02174 4.02168 4.02164 4.02163 4.02160 4.02160 4.02155 4.02160 4.02208

Display panel 41-50 is the PDP that makes according to present embodiment.Display panel 41-50 makes under the different condition in bonding process.That is, panel is heated in dissimilar atmosphere with under the different pressure, and they are placed on together by different timings under different temperature.

Each display panel is all temporarily cured under 350 ℃ of temperature.

For display panel 41-46,48-50, to use to have the strong dry gas of different vapor partial pressures as protective gas, the strong scope of vapor partial pressure is the 0-12 torr.Display panel 47 heated while gas bleedings form vacuum.

For display panel 43-47, panel is heated to 400 ℃ (being lower than the softening point of seal glass) from room temperature, is placed on rear board.Panel is further heated 450 ℃ (softening points that are higher than seal glass), and this temperature maintenance 10 minutes is reduced to 350 ℃ then, and bleeds when keeping 350 ℃ of temperature.

For display panel 41 and 42, panel is respectively to bond under the lower temperature of 250 ℃ and 350 ℃.

For display panel 48, panel is heated to 450 ℃, is placed on together under this temperature subsequently.For display panel 49, panel is heated to 500 ℃ (peak temperatures), is placed on together under this temperature subsequently.

For display panel 50, panel is heated to 480 ℃ of peak temperatures, is reduced to 450 ℃ subsequently, and panel is placed and bonds together at 450 ℃.

Display panel 51 is the PDP that make according to a kind of mapping mode of the embodiment 5 shown in Figure 24 A-24C, and wherein panel is heated to 450 ℃ (peak temperatures), is placed and bonds together under this temperature subsequently.

Display panel 52 is PDP as a comparative example, and it is by at room temperature panel being put together, and 450 ℃ of bondings make by in the dry air of atmospheric pressure they being heated to subsequently.

Should be pointed out that the thickness of phosphor layer is 30 μ m in each of PDP 41-52, discharge gas Ne (95%)-Xe (5%) fills by the inflation pressure of 500 torrs, like this they each all have identical display panel structure.

Characteristics of luminescence test

For among the PDP 41-52 each, measured following characteristic: the peak wavelength of the chromaticity coordinate y of the relative luminous intensity of the blue light of being launched, the blue light of being launched, the blue light of being launched, the display panel brightness when not having under the colour correction situation and colour temperature and from the spectrum of blue cell emission and ratio from the peak strength of the spectrum of green cell emission in white balance as the characteristics of luminescence.

Each PDP of manufacturing is taken apart, and use the krypton Excimer lamp that the blue fluorescent substance layer of rear board is carried out vacuum ultraviolet (centre wavelength is 146nm) irradiation.Subsequently, measure the chromaticity coordinate y of blue light.

The result is presented in the table 5.The relative luminous intensity value that should be pointed out that the blue light shown in the table 5 is the relative value when the luminous intensity of the display panel of measuring as a comparative example 52 is set to standard value 100.

In addition, each PDP of manufacturing is taken apart, and use the krypton Excimer lamp that the blue fluorescent substance layer of rear board is carried out the vacuum ultraviolet irradiation.Subsequently, measure when the colour temperature of light during and the ratio of the peak strength of the spectrum launched from the spectrum of blue cell emission with from green cell from whole indigo plants, red and green cell emission.The result is identical with above-mentioned result.

Figure 25 only demonstrates from the spectrum of the blue cell emission of the PDP of display panel 45,50 and 52.

Though table 5 does not illustrate, roughly be identical from the redness of display panel 41-51 and the chromaticity coordinate x of the light of green cell emission with y: red (0.636,0.350), green (0.251,0.692).In PDP as a comparative example, be (0.170,0.090) from the chromaticity coordinate x and the y of the light of blue cell emission, the peak wavelength in the spectrum of being launched is 458nm.

Then, take out blue fluorescent substance from panel.Adopt the TDS analytic approach, measure a gram H of desorb from blue fluorescent substance ₂The molecular number that comprises in the O gas.In addition, by X-ray analysis, measure the c shaft length of blue fluorescent substance crystal and the ratio of a shaft length.The result is also shown in the table 5.

Analyze

Can notice: the characteristics of luminescence of display panel 41-51 is better than display panel 52 (show as have higher blue light luminous intensity and less chromaticity coordinate y).This can be regarded as and is based on following reason: compare with the situation of according to conventional methods bonding panel, the gas flow that discharges in the inner space after the panel that bondd according to present embodiment between panel still less.

In the PDP of display panel 52, be 0.088 from the chromaticity coordinate y of the light of blue cell emission, and the colour temperature when not having under the colour correction situation in white balance is 5800K.By contrast, in display panel 41-51, these values are respectively 0.08 or littler and 6500K or bigger.Particularly, can notice: in the less display panel 48-51 of the chromaticity coordinate y of blue light, realized (when not having under the colour correction situation) high colour temperature of about 11000K in white balance.

Figure 26 is an XYZ chromaticity diagram, demonstrates near the blue color rendering zone of the PDP of present embodiment and comparative example on it.

In the figure, near the blue color rendering zone of following situation (corresponding to display panel 52) is represented in zone (a): wherein the chromaticity coordinate y of blue light is about 0.09 (peak wavelength of the spectrum of emission is 458nm); Near the blue color rendering zone of following situation (corresponding to display panel 41) is represented in zone (b): wherein the chromaticity coordinate y of blue light is about 0.08 (peak wavelength of the spectrum of emission is 455nm); Near the blue color rendering zone of following situation (corresponding to display panel 50) is represented in zone (c): wherein the chromaticity coordinate y of blue light is about 0.052 (peak wavelength of the spectrum of emission is 448nm).

Can notice from this figure: near the color rendering zone blue is by the order expansion of regional (a) and (b), (c).This shows can make PDP like this: the chromaticity coordinate y of blue light more little (peak wavelength of the spectrum of emission is short more) wherein, near the color rendering zone blue is just wide more.

The characteristics of luminescence by display panel 41,42,45 and 48 relatively (in each in the dry gas partial pressure of steam be 2 torrs), can notice: the characteristics of luminescence is improved (luminous intensity increases, and chromaticity coordinate y reduces) by the order of display panel 41,42,45 and 48.This shows: the heating-up temperature when bonding front panel 10 and rear board 20 is set highly more, and the improvement of the characteristics of luminescence of PDP is big more.

This can be regarded as and is based on following reason: when before the panel bonding, it is preheated when the high temperature when panel is separated from each other, after panel bonding, can discharge the gas of less amount in the inner space between panel, because the gas that discharges from panel has been extracted out fully.

By comparing the characteristics of luminescence of display panel 43-46 (they have identical Temperature Distribution in bonding process), can notice: the characteristics of luminescence is improved (chromaticity coordinate y reduces in this order) by the order of display panel 43,44,45 and 46.This shows: the partial pressure of steam is low more in the protective gas, and the improvement of the characteristics of luminescence of PDP is big more.

By comparing the characteristics of luminescence of display panel 46 and 47 (they have identical Temperature Distribution in bonding process), can notice: display panel 46 is better than display panel 47 slightly.

This can be regarded as and is based on following reason: a part of oxygen discharges from the fluorescent material as oxide and cause oxygen defect in display panel 47; because display panel 47 is preheated in the atmosphere of anaerobic, and display panel 46 is preheated in the oxygen containing protective gas of bag.

Can notice: display panel 48 almost is identical with 51 the characteristics of luminescence.This shows: preheat panel and between panel local detachment both of these case, the characteristics of luminescence of PDP does not almost have difference when panel is separated from each other fully.

From table 5, can notice: no matter be that vacuum ultraviolet shines or by only measuring from blue fluorescent substance layer emission light, the value of chromaticity coordinate y almost is identical by the blue fluorescent substance layer is carried out.

Focus onto each listed in the table 5 display panel launch blue light chromaticity coordinate y and launch relation between the peak wavelength of blue light, can notice that along with chromaticity coordinate y reduces, peak wavelength shortens.This shows between them it is directly proportional relation.

＜embodiment 6 〉

The PDP of present embodiment has 1 identical construction with embodiment.

The PDP manufacture method of present embodiment is identical with embodiment 5 except following difference: after at least one in seal glass being coated to front panel 10 and rear board 20, temporary transient baking process, bonding process and air aspiration process are carried out in the heating furnace 81 of stamping device 80 continuously.

To explain temporary transient baking process, bonding process and the air aspiration process of present embodiment below.

These technologies are to adopt the stamping device shown in Figure 19 and 20 to carry out.But, in the present embodiment, as shown in Figure 27 A-27C, a conduit 90 inserts the heating furnace 81 from the outside, and is connected to glass tube 26, and glass tube 26 is installed on the pore 21a of rear board 20.

Figure 27 A, 27B and 27C demonstrate the operation of using stamping device to carry out in the air aspiration process process at temporary transient baking process.

With reference to these figure temporary transient baking process, bonding process and air aspiration process are described below.

Temporary transient baking process

With the seal glass slurry coating on following one of column region: the perimeter facing to that side of rear board 20 of front panel 10; The perimeter facing to that side of front panel 10 of rear board 20; And the perimeter of the opposed facing side of front panel 10 and rear board 20.It may be noted that in the drawings seal glass layer 15 is formed on the front panel 10.

After appropriate location, front panel 10 and rear board 20 are put together.Subsequently, a fixed position that panel is placed on the base 84 is located.Then dipper crowding gear 86 is arranged to push rear board 20 (Figure 27 A).

Subsequently, protective gas (dry air) is circulated (perhaps, passing through vent valve 83 gas bleedings simultaneously to form vacuum) in heating furnace 81, carry out following operation simultaneously.

Slipping column 85 is risen, thereby make rear board 20 move to a position (Figure 27 B) parallel with self.This makes the space between front panel 10 and the rear board 20 widen, and the phosphor layer on the rear board 20 25 is exposed to a big space in the heating furnace 81.

Under above state heating furnace 81 is heated to temporary transient stoving temperature (about 350 ℃), counter plate temporarily heated 10-30 minute under this temperature subsequently.

Preheat technology

Counter plate 10 and 20 further heats, so that panel discharges gas, these gases are trapped on the panel by absorption.When reaching predetermined temperature (for example 400 ℃), preheat technology and finish.

Bonding process

Slipping column 85 is descended, thereby front and back panel is put together once more.That is, rear board 20 is placed its correct position (Figure 27 C) on plate 10 in front again.

When heating furnace 81 inside have reached the specific sticking temperature (about 450 ℃) of the softening point that is higher than seal glass layer 15, kept sticking temperature 10-20 minute.In this cycle, the perimeter of front panel 10 and rear board 20 is bonded together by softening seal glass.Because in the cycle, rear board 20 is pushed front panel 10 to by dipper crowding gear 86 in this bonding, so panel is realized bonding with high stability.

Air aspiration process

Make the inside of heating furnace be cooled to be lower than the extraction temperature of the softening point of seal glass layer 15.Under this temperature, cure panel (for example curing 1 hour) at 350 ℃.Gas bleeding the inner space between the panel of bonding forms high vacuum degree (8 * 10 ^-7Torr).Air aspiration process is to use a vacuum pump (not shown) to carry out, and this vacuum pump is connected to conduit 90.

Subsequently, with the panel cool to room temperature, keep the vacuum of inner space simultaneously.Fill discharge gas by glass tube 26 to the inner space.After blocked and glass tube 26 was cut off at pore 21a, this PDP had just finished.

The effect of the manufacture method of showing in the present embodiment

The manufacture method of present embodiment has following effect, and these effects can not obtain from conventional method.

Usually, temporary transient baking process, bonding process and air aspiration process are to use a heating furnace separately to carry out, and the each between technology is cooled to room temperature every middle panel.In this manner, need long time and consumption lot of energy in each technology, to heat panel.On the contrary, in the present embodiment, these technologies are carried out in same heating furnace continuously, and do not need temperature is reduced to room temperature.This has reduced and has heated required time and energy.

In the present embodiment, temporary transient baking process carries out apace to bonding process, and energy consumption is low, because temporary transient baking process is to carry out in that heating furnace 81 is heated in the temperature required pilot process of bonding process with preheating technology.In addition, in the present embodiment, bonding process carries out apace to air aspiration process, and energy consumption is low, because air aspiration process is to carry out in the pilot process of panel cool to room temperature after bonding process.

In addition, just as will be descr, compare with conventional adhesive method, present embodiment has the effect identical with embodiment 5.

Usually, the gas resemble steam can be trapped on the surface of front panel and rear board by absorption.Gas adsorbed when panel is heated just discharges.

In conventional method, in the bonding process after temporary transient baking process, front panel and rear board at first at room temperature are placed on together, and they are heated and bond together subsequently.In bonding process, the lip-deep gas that is trapped in front panel and rear board by absorption can discharge.Though can discharge a certain amount of gas in temporary transient baking process, before bonding process began, when panel was placed in the air cool to room temperature, these gases were detained once more by absorption, and these gases discharge in bonding process.The gas that discharges is limited in the little space between the panel.When this happens, owing to heated influence with gas, the influence of the steam that especially protected layer 14 discharges, it is bad that phosphor layer is tending towards becoming.The bad luminous intensity of these layers that makes of the change of phosphor layer reduces.

On the other hand, according to the manufacture method of showing in the present embodiment, the gas that discharges from panel can not be limited in the inner space, because in bonding process or preheat in the technology, forms a wide gap between the panel.In addition, because panel is heated continuously in the bonding process after preheating technology, water etc. can not be trapped on the panel by absorption after preheating technology.Therefore, in bonding process, have only gas seldom to discharge from panel.This becomes bad with regard to having prevented phosphor layer 25 because of heating.

In addition, when at first the position being adjusted when suitable, adopt the stamping device 80 of present embodiment panel can be bonded in suitable position.

Moreover in the present embodiment, preheating technology is to carry out in the atmosphere of dry gas circulation to bonding process.This can prevent to cause phosphor layer 25 to become bad owing to the steam that heats and be included in the protective gas.

The following optimum condition of present embodiment identical with described in the embodiment 5: pre-warmed temperature; The timing that panel puts together; The type of protective gas; Pressure; And the partial pressure of steam.

The mapping mode of present embodiment

In the present embodiment, temporary transient baking process, preheat technology, bonding process and air aspiration process and in identical device, carry out continuously.But, when omission preheats technology, can obtain identical effect to a certain extent.In addition, if be that temporary transient baking process and bonding process carry out in identical device continuously, if perhaps just bonding process and air aspiration process be in identical device, to carry out continuously, also can obtain identical effect to a certain extent.

In the present embodiment, after bonding process, the inside of heating furnace is cooled to below the extraction temperature (350 ℃) of the softening point of seal glass, and bleeds under this temperature.But, bleed under the high temperature also can be in resembling bonding process.In this case, in the short time, just can bleed fully.But, should form some structures (for example, the partition member shown in Figure 10-16) for this reason, even so that the seal glass layer is softening, the seal glass layer can not flow yet and leave the position that should locate.

In the present embodiment, when plate 10 and rear board 20 are separated from each other in front, carry out temporary transient baking process and preheat technology.But, can adopt the method for embodiment 3 to carry out temporary transient baking process, bonding process and air aspiration process continuously, in the method for embodiment 3, panel is placed on together after being positioned properly, be heated and bond with rear board, the pressure of inner space reduces and dry air is supplied to the inner space simultaneously.

Explain said method now.Use the sealing-in firing equipment 50 shown in Fig. 5.At first, seal glass is applied on one of front panel 10 and rear board 20 or both, forms seal glass layer 15. Panel 10 and 20 is positioned properly, under the situation of temporarily not curing, is placed on together subsequently, and place heating furnace 51.

A conduit 52a is connected to glass tube 26a, and glass tube 26a is connected on the pore 21a of rear board 20.Use a vacuum pump (not shown), by conduit 52b, space gas bleeding internally.Simultaneously, supply with dry air by a conduit 52b to the inner space, conduit 52b is connected to glass tube 26b, and glass tube 26b is connected on the pore 21b of rear board 20.Like this, when dry air flowed by the inner space, the pressure of inner space had been lowered.

Keep in the space between panel 10 and 20 under the situation of above-mentioned state, the inside of heating furnace 51 is heated to temporary transient stoving temperature, and counter plate temporarily cures (curing 10-30 minute at 350 ℃).

Here, if cure simply after panel puts together, panel can not be cured fully in temporary transient baking process so, supplies with oxygen because be difficult to the seal glass layer.But, if cure panel when dry air is flowed through inner space between the panel, panel then can be cured fully.

Raise the temperature to the specific sticking temperature higher, and this sticking temperature is kept certain cycle (for example, 450 ℃ peak temperature kept 30 minutes) than the softening point of seal glass.In this cycle, front panel 10 and rear board 20 bond together by softening seal glass.

Make the inside of heating furnace 51 be cooled to be lower than the extraction temperature of the softening point of seal glass.By keeping this extraction temperature, the inner space gas bleeding between the panel of bonding forms high vacuum degree.After this air aspiration process, with the panel cool to room temperature.Fill discharge gas by glass tube 26 to the inner space.After blocked and glass tube 26 was cut off at pore 21a, this PDP had just finished.

In the example of this conversion, in the method for present embodiment, temporary transient baking process, bonding process carry out in identical stamping device continuously with air aspiration process, simultaneous temperature is not reduced to room temperature.Therefore, these technologies also can be carried out apace, and it is low to consume energy.

In the example of this conversion, if be that temporary transient baking process and bonding process carry out in heating furnace 51 continuously, if perhaps just bonding process and air aspiration process are to carry out continuously, also can obtain identical effect to a certain extent in heating furnace 51.

Example 6

＜table 6 〉

Table 6

The display panel numbering	Temporarily cure frit temperature (℃)	The temperature that front and back panel is put together (℃)	The temperature of bonding panel (℃)	The temperature of bleeding (℃)	Atmosphere during bonding	The partial pressure of steam (torr) in the dry air	The relative luminous intensity of blue light	The chromaticity coordinate Y of blue light	Colour temperature during white balance (K)	The peak strength of the spectrum of blue light and green glow is than (blue/green)	Adopt TDS to analyze under 200 ℃ or higher temperature H from the blue fluorescent substance desorb 2The maximum quantity of molecule in the O gas	The axial length of blue fluorescent substance crystal is than (c-axle/a-axle)
													61 62 63 64 65 66 67 68 69 70	350 350 350 350 350 350 350 350 350 350	250 350 400 400 400 400 400 450 480 -	450 450 450 450 450 450 450 450 450 450	350 350 350 350 350 350 350 350 350 350	Dry air dry air dry air dry air dry air dry air vacuum drying air dry air air	2 2 12 8 2 0 - 2 2 -	107 118 108 112 120 123 120 125 126 100	0.078 0.057 0.075 0.065 0.055 0.053 0.053 0.052 0.052 0.090	6700 8600 7100 7800 9000 9800 9300 10600 11000 5800	0.80 0.95 0.82 0.91 0.98 1.09 1.03 1.15 1.19 0.67	1.0×10 16 4.0×10 15 7.3×10 15 5.2×10 15 3.4×10 15 2.3×10 15 1.3×10 15 1.9×10 15 1.3×10 15 2.6×10 16	4.02180 4.02172 4.02178 4.02174 4.02168 4.02165 4.02155 4.02160 4.02155 4.02208

Display panel 61-69 is the PDP that makes according to present embodiment.Display panel 61-69 makes under the different condition in bonding process.That is, panel is heated in dissimilar atmosphere with under the different pressure, and they are placed on together by different timings under different temperature.

Figure 28 demonstrates the Temperature Distribution of using in temporary transient baking process, bonding process and air aspiration process when making display panel 63-67.

For display panel 61-66,68 and 69, to use to have the strong dry air of different vapor partial pressures, the strong scope of vapor partial pressure is the 0-12 torr.For display panel 70, use non-dry air.Display panel 67 heated while gas bleedings form vacuum.

For display panel 63-67, panel is heated to 350 ℃ from room temperature.By keeping under this temperature 10 minutes, panel is temporarily cured.Subsequently, panel is heated to 400 ℃ (being lower than the softening point of seal glass), and panel is placed on together then.Panel is further heated 450 ℃ (softening points that are higher than seal glass), and this temperature maintenance 10 minutes is reduced to 350 ℃ then, and bleeds when keeping 350 ℃ of temperature.

For display panel 61 and 62, panel is respectively to bond under the lower temperature of 250 ℃ and 350 ℃.

For display panel 68, panel is heated to 450 ℃, is placed on together under this temperature subsequently.For display panel 69, panel is heated to 480 ℃ peak temperature, is reduced to 450 ℃ subsequently, and panel is placed and bonds together at 450 ℃.

Display panel 70 is PDP as a comparative example, and it is made according to conventional methods, and in conventional method, panel is temporarily cured, at room temperature is placed on together, is heated to 450 ℃ sticking temperature and 450 ℃ of bondings in the air of atmospheric pressure.Be cooled to room temperature with rear board, and then in heating furnace, be heated to 350 ℃ extraction temperature.By maintaining 350 ℃ temperature, gas is drawn out of in the space internally.

Should be pointed out that the thickness of phosphor layer is 30 μ m in each of PDP 61-70, discharge gas Ne (95%)-Xe (5%) fills by the inflation pressure of 500 torrs, like this they each all have identical display panel structure.

Characteristics of luminescence test

For among the PDP 61-70 each, measured following characteristic: the peak wavelength of the chromaticity coordinate y of the relative luminous intensity of the blue light of being launched, the blue light of being launched, the blue light of being launched, the colour temperature when not having under the colour correction situation and from the spectrum of blue cell emission and ratio from the peak strength of the spectrum of green cell emission in white balance as the characteristics of luminescence.

The result is presented in the table 6.The relative luminous intensity value that should be pointed out that the blue light shown in the table 6 is the relative value when the luminous intensity of the display panel of measuring as a comparative example 70 is set to standard value 100.

Each PDP of manufacturing is taken apart, and use the krypton Excimer lamp that the blue fluorescent substance layer of rear board is carried out the vacuum ultraviolet irradiation.Subsequently, measure the blue light launched chromaticity coordinate y, when light during from whole indigo plants, red and green cell emission colour temperature and from the spectrum of blue cell emission with from the ratio of the peak strength of the spectrum of green cell emission.The result is identical with above-mentioned result.

Then, take out blue fluorescent substance from panel.Adopt the TDS analytic approach, measure a gram H of desorb from blue fluorescent substance ₂The molecular number that comprises in the O gas.In addition, by X-ray analysis, measure the c shaft length of blue fluorescent substance crystal and the ratio of a shaft length.The result is also shown in the table 6.

Analyze

For among the PDP 61-70 each, measured following characteristic: the peak wavelength of the chromaticity coordinate y of the relative luminous intensity of the blue light of being launched, the blue light launched, the blue light of being launched and the colour temperature when not having under the colour correction situation (when the colour temperature of light when blue, red and green cell form white developing with the identical energy emission) in white balance as the characteristics of luminescence.

＜test result 〉

The result of this test is presented in the table 6.The relative luminous intensity value that should be pointed out that the blue light shown in the table 6 is the relative value when the luminous intensity of the display panel of measuring as a comparative example 70 is set to standard value 100.

Can notice from table 6: the characteristics of luminescence of display panel 61-69 is better than display panel 70 (show as have higher blue light luminous intensity and less chromaticity coordinate y).This can be regarded as and is based on following reason: compare with the situation of according to conventional methods bonding panel, the gas flow that discharges in the inner space after according to present embodiment bonding panel between panel still less.

In display panel 70, be 0.090 from the chromaticity coordinate y of the light of blue cell emission, and the colour temperature when not having under the colour correction situation in white balance is 5800K.By contrast, in display panel 61-69, these values are respectively 0.08 or littler and 6500K or bigger.Particularly, can notice: in the less display panel 68 and 69 of the chromaticity coordinate y of blue light, realized (when not having under the colour correction situation) high colour temperature of about 11000K in white balance.

The characteristics of luminescence by display panel 61,62,65,68 and 69 relatively (in each in the dry gas partial pressure of steam be 2 torrs), can notice: the characteristics of luminescence is improved (luminous intensity increases, and chromaticity coordinate y reduces) by the order of display panel 61,62,65,68,69.This shows: the heating-up temperature when bonding front panel 10 and rear board 20 is set highly more, and the improvement of the characteristics of luminescence of PDP is big more.

By comparing the characteristics of luminescence of display panel 63-66 (they have identical Temperature Distribution in bonding process), can notice: the characteristics of luminescence is improved (chromaticity coordinate y reduces in this order) by the order of display panel 63,64,65 and 66.This shows: the partial pressure of steam is low more in the protective gas, and the improvement of the characteristics of luminescence of PDP is big more.

By comparing the characteristics of luminescence of display panel 66 and 67 (they have identical Temperature Distribution in bonding process), can notice: display panel 66 is better than display panel 67 slightly.

This can be regarded as and is based on following reason: part of oxygen discharges from the fluorescent material as oxide and cause oxygen defect in display panel 67; because display panel 67 is preheated in the atmosphere of anaerobic, and display panel 66 is preheated in the oxygen containing protective gas of bag.

Other

In the foregoing description 1-6, the situation of making surface discharge type PDP has been described.But, the present invention also can be applied to make the situation of opposed discharge (opposed-discharge) type PDP.

The fluorescent material of the composition of in having the foregoing description, showing, use the fluorescent material that is generally used for PDP also can realize the present invention.

Generally speaking, in embodiment 1-6, seal glass applies after phosphor layer forms.But, the order of these technologies can be put upside down.

Industrial applicability

PDP of the present invention and make the method for PDP can be effectively for the manufacture of the display of computer or TV, in particular for making large screen display.

Claims (2)

1. PDP, it is included in a plurality of unit that form between a pair of panel that is parallel to each other, and comprises blue cell in these a plurality of unit, is formed with the blue fluorescent substance layer in each blue cell, and these a plurality of unit are filled with gas medium, wherein

The blue fluorescent substance layer is by BaMgAl ₁₀O ₁₇: Eu makes, and

The ratio of c shaft length and a shaft length is 4.0218 or littler in the crystal of blue fluorescent substance layer.

2. PDP, it is included in a plurality of unit that form between a pair of panel that is parallel to each other, and comprises blue cell in these a plurality of unit, is formed with the blue fluorescent substance layer in each blue cell, and these a plurality of unit are filled with gas medium, wherein

The blue fluorescent substance layer is by BaMgAl ₁₀O ₁₇: Eu makes, and

When measuring, under 200 ℃ or higher temperature, from the H of blue fluorescent substance layer desorb according to the TDS analytic approach ₂The maximum of the molecular amounts that comprises among the O is 1 * 10 ¹⁶/ gram or still less.

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