JP3183290B1 - Plasma display panel and method of manufacturing the same - Google Patents

Abstract

An object of the present invention is to provide a plasma display panel in which a decrease in emission intensity and chromaticity of a blue phosphor is small and a discharge voltage is low, and a method of manufacturing the same. SOLUTION: A step of introducing steam into a discharge space between a front plate 1 and a back plate 2 after sealing is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel (PDP) using gas discharge light emission for use in a color television receiver or display for displaying characters or images, and a method and apparatus for manufacturing the same. is there.

[0002]

2. Description of the Related Art A conventional plasma display panel will be described below with reference to the drawings. FIG. 9 is a cross-sectional view schematically showing an AC type (AC type) plasma display panel.

In FIG. 9, reference numeral 41 denotes a front glass substrate, on which display electrodes 42 are formed. Further, the display electrode 42 is provided on the dielectric glass layer 4.
3 and a magnesium oxide (MgO) dielectric protection layer 44 (see, for example, JP-A-5-342991).

Reference numeral 45 denotes a rear glass substrate. On the rear glass substrate 45, address electrodes 46, partition walls 47, and phosphor layers (50 to 52) are provided.
Reference numeral 9 denotes a discharge space for filling a discharge gas. The phosphor layer has red 50, green 51, and blue 52 for color display.
Are arranged in order. Each of the phosphor layers (50 to 52) emits and emits light by vacuum ultraviolet rays (wavelength: 147 nm) having a short wavelength generated by discharge.

The following materials are generally used as the phosphors constituting the phosphor layers 50 to 52.

Blue phosphor: BaMgAl ₁₀ O ₁₇ : Eu Green phosphor: Zn ₂ SiO ₄ : Mn or BaAl ₁₂ O
_19: Mn Red phosphor: Y ₂ O _3: Eu or _{(Y x Gd 1-x)} B
O ₃ : Eu front glass substrate 41, rear glass substrate 45 and partition wall 4
A discharge gas is sealed in a discharge space surrounded by 7. The composition of the discharge gas is generally helium [H
e] and xenon [Xe] or neon [Ne]
And a mixed gas system of xenon [Xe] and
The sealing pressure is usually 13.3 kPa (100 Torr) in consideration of keeping the discharge voltage at 250 V or less.
The range is set to about 80 kPa (600 Torr).

Hereinafter, a conventional PDP manufacturing method will be described.

An address electrode made of silver is formed on a rear glass substrate, and a visible light reflecting layer made of dielectric glass and a partition made of glass are formed on the address electrode made of silver at a predetermined pitch.

A phosphor layer is formed by disposing a phosphor paste of each color including a red phosphor, a green phosphor, and a blue phosphor in each space interposed between these partition walls, and after forming, a phosphor layer is formed at 500 ° C. The phosphor layer is baked to a degree to remove resin components and the like in the paste (phosphor baking step).

After firing the phosphor, a low-melting glass paste is applied around the rear plate as a sealing material for sealing with the front plate,
In order to remove the resin component and the like in the low melting point glass paste, it is calcined at about 350 ° C. (low melting point glass paste calcining step).

Thereafter, the front plate on which the display electrode, the dielectric glass layer and the protective layer are sequentially formed, and the rear plate are arranged so as to face each other with the display electrode and the address electrode interposed at right angles via a partition, and baked at about 450 ° C. The surroundings are sealed with low melting point glass (sealing step).

Thereafter, the inside of the panel is evacuated while being heated to about 350 ° C. (evacuation step), and after completion, a discharge gas is introduced at a predetermined pressure.

The principle of light emission of a PDP is basically the same as that of a fluorescent lamp. By applying glow discharge to an electrode to generate ultraviolet rays from Xe, the phosphor is excited and emits light.

[0014]

Under such a background, there is a demand for a technique for a PDP which improves luminous efficiency to realize high luminance and suppresses a discharge voltage.

[0015] Further, in the sealing step of manufacturing a PDP, there is a problem that the phosphor used is thermally degraded, and the degradation of the blue phosphor is particularly large. It is considered that this is because BaMgAl ₁₀ O ₁₇ : Eu used as a blue phosphor reacts with water vapor in the sealing step, causing a decrease in emission intensity and deterioration of emission chromaticity. To prevent this, it is effective to set the atmosphere at the time of sealing to a dry atmosphere.

On the other hand, however, there is a problem that the discharge voltage becomes higher as the atmosphere at the time of sealing is dried.

In view of the above problems, the present invention provides a plasma display panel which hardly undergoes thermal deterioration of a phosphor and has a low discharge voltage even through a sealing step required for a panel manufacturing process. The purpose is to do so.

[0018]

In order to achieve the above object, a method for manufacturing a plasma display panel according to the present invention comprises a front substrate and a rear substrate, each having at least one phosphor provided thereon, and an internal space between the substrates. A method for manufacturing a plasma display panel having a sealing step of overlapping and sealing so that is formed, after the sealing step,
A step of introducing steam into the internal space is provided.

In the above structure, after the sealing step, 1
It is preferable to provide a step of heating the plasma display panel to a temperature of not less than 00 ° C. and not more than 350 ° C. to introduce water vapor into the internal space.

Preferably, after the sealing step, a step of flowing a gas containing at least water vapor into the internal space is provided.

Preferably, after the sealing step, a step of exposing the plasma display panel to a gas atmosphere containing at least water vapor is provided.

Water vapor is introduced into the internal space, and the partial pressure of water vapor in the internal space is set to 1.3 kPa (10 Torr).
r) or more is preferable.

Further, in the method of manufacturing a plasma display panel according to the present invention, a front substrate and a rear substrate, each having a phosphor disposed on at least one of them, are overlapped and sealed so that an internal space is formed between the two substrates. A method of manufacturing a plasma display panel having a sealing step, wherein the sealing step introduces water vapor into the internal space when the temperature of the plasma display panel decreases after heating to a peak temperature.

In the above structure, it is preferable to introduce water vapor into the internal space after heating the plasma display panel to a peak temperature and then lowering the temperature to 350 ° C. or lower.

In the sealing step, it is preferable that a gas containing at least water vapor is allowed to flow into the internal space when the temperature of the plasma display panel is decreased after heating to a peak temperature.

In the sealing step, it is preferable that the atmosphere around the plasma display panel is filled with a gas containing at least water vapor when the temperature of the plasma display panel drops to a peak temperature after heating.

In the sealing step, at least until the plasma display panel is heated to a peak temperature.
Preferably, a dry gas is introduced into the internal space.

Further, steam is introduced into the internal space,
The partial pressure of water vapor in the internal space is set to 1.3 kPa (10 Torr).
r) or more is preferable.

[0029]

Embodiment 1 Hereinafter, a method for manufacturing a plasma display panel according to Embodiment 1 of the present invention will be described. FIG. 8 is a sectional view schematically showing an AC surface discharge type plasma display panel according to one embodiment of the present invention. Although only one cell is shown in FIG. 8, a PDP is configured by arranging a large number of cells that emit red, green, and blue light.

This PDP comprises a display electrode 22, a dielectric glass layer 23, and a protective layer (MgO) 2 on a front glass substrate 21.
4 and a back plate on which an address electrode 26, a visible light reflection layer 27, a partition wall 28 and a phosphor layer 29 are disposed on a back glass substrate 25, and formed between the front plate and the back plate. A discharge gas is sealed in a discharge space to be discharged.

As the composition of the phosphor material constituting the phosphor layer, those generally used for the phosphor layer of PDP can be used. Specific examples thereof include blue phosphor: BaMgAl ₁₀ O ₁₇ : Eu green phosphor: Zn ₂ SiO ₄ : Mn red phosphor: (Y, Gd) BO ₃ : Eu.

FIG. 2 and FIG. 3 show that when the used blue phosphor (BaMgAl ₁₀ O ₁₇ : Eu) was calcined in air at a peak temperature of 450 ° C. for 20 minutes, the water vapor partial pressure of air was changed. The relative emission intensity and chromaticity coordinate y
The measurement results of the water vapor partial pressure dependency are shown respectively. The relative emission intensity is set to 100 as the emission intensity of the blue phosphor before firing. The chromaticity coordinate y of the blue phosphor before firing is 0.05
It was 2.

When the partial pressure of water vapor was around 0 Pa (0 Torr), no thermal degradation of luminescence intensity and no change in chromaticity were observed at all, but the relative luminescence intensity became weaker as the partial pressure of water vapor increased. Has grown. As the chromaticity y of the blue phosphor increases, the color reproduction range of the panel becomes narrower and the color temperature of the panel lowers.

Conventionally, a blue phosphor (BaMgAl ₁₀ O ₁₇ :
It is considered that the reason why the emission intensity is deteriorated by heating Eu) or the chromaticity y is increased is that the activator Eu ²⁺ ions are oxidized by heating to become Eu ³⁺ ions. However, as a result of the measurement of the partial pressure of water vapor, it is considered that these deteriorations are not caused by oxidation of Eu ²⁺ ions reacting with oxygen in the atmosphere (for example, air), but are caused by heat deterioration caused by water vapor in the atmosphere. That is, by reducing the partial pressure of water vapor in the atmosphere, the blue phosphor (BaMgAl ₁₀ O
₁₇ : It was found that thermal degradation due to heating of Eu) could be prevented.

In consideration of the manufacturing process of the plasma display panel, the sealing step of sealing the front plate and the back plate is narrower than that of the phosphor baking step or the low-melting glass paste calcining step by partitioning the partition wall or the like. Since the gas is confined in the space, the influence of the gas containing water vapor released from the protective layer (Mg0) on the front plate, the phosphor layer formed on the back plate, or the low melting point glass paste for sealing during heating is greatly increased. Therefore, it is important that the atmosphere at the time of sealing be a dry atmosphere.

On the other hand, as for the discharge voltage, the discharge voltage tends to increase as the atmosphere at the time of sealing is changed to a dry atmosphere (ie, the deterioration of the blue phosphor is prevented). FIG. 4 shows the blue light emission intensity and the discharge voltage of a PDP manufactured by changing the partial pressure of water vapor in the panel at the time of sealing. Here, the discharge voltage is a minimum voltage necessary for lighting the PDP in white display on the entire surface.

On the contrary, the discharge voltage can be reduced as the residual moisture in the PDP after sealing increases.

Therefore, a manufacturing method in this embodiment for lowering the discharge voltage while suppressing deterioration of the blue phosphor at the time of sealing will be described with reference to FIG.

The panel comprising the sealed front plate 1 and back plate 2 was placed in the heating furnace 3 after sealing. The rear plate 2 is provided with at least two glass tubes 4 also serving as exhaust pipes. From the glass tube 4a, a dry air cylinder 5a,
By 5b, the flow controllers 6a and 6b and the water bubbling device 7, air containing water vapor whose vapor partial pressure is adjusted is introduced into the panel and discharged through the glass tube 4b.

The panel was heated to a certain temperature by a heating furnace while air containing water vapor was flowing into the panel.

Although the discharge voltage was reduced only by flowing air containing water vapor into the panel without heating the panel, the effect became remarkable when the panel was heated to 100 ° C. or higher. The discharge voltage tended to decrease. However, on the other hand, if the heating temperature is too high, the blue phosphor reacts with water vapor to deteriorate the blue phosphor. FIG.
The heating temperature dependence of the emission intensity when the blue phosphor is fired in the air containing water vapor through the bubbling device 7 is shown in FIG. As can be seen from FIG. 5, in this step, the heating is preferably performed at 350 ° C. or lower so that the blue phosphor is not significantly deteriorated.

When the partial pressure of water vapor in the air containing water vapor was 1.3 kPa (10 Torr) or more, the discharge voltage was significantly reduced.

In the present embodiment, the steam is forcibly introduced into the PDP through the glass tube 4. However, the atmosphere around the PDP (in this embodiment, the atmosphere in the heating furnace 3) is changed to the steam. There was also an effect when the gas atmosphere was used. This is because the water vapor in the atmosphere around the PDP naturally replaces the gas inside the PDP through the glass tube 4,
It is considered to enter P. However, in this case, a longer time was required for sufficient replacement than in the case where steam was forcibly introduced into the PDP.

After the completion of this step of introducing water vapor into the PDP, the inside of the PDP was evacuated from the glass tube 4 and then a discharge gas was introduced to seal the glass tube to complete the panel.

In the evacuation step, a part of the water vapor introduced into the PDP is adsorbed by MgO or the like and remains in the PDP. .

(Embodiment 2) Next, a method of manufacturing a plasma display panel according to Embodiment 2 of the present invention will be described with reference to FIG.

A panel in which the front plate 8 and the back plate 9 before sealing were attached to each other was set in a sealing furnace 15. On the backboard 9,
At least two glass tubes 10 serving as an exhaust pipe are provided. In the glass tube 10a, a dry air cylinder 11a,
11b, flow controllers 12a, 12b, valve 13
a, 13 b and a water bubbling device 14 are connected, and by switching the valve 13, dry air or air containing steam having a regulated partial pressure of steam can be introduced into the panel, and the glass tube 10 b Is discharged through.

FIG. 7 shows a heating temperature profile at the time of sealing in this embodiment. In the present embodiment, the drying gas is introduced into the PDP from the start of heating (A in the figure), and the drying gas continues to flow through the heating peak temperature (B in the figure) and during the temperature drop (C in the figure). Thus, deterioration of the blue phosphor at the time of sealing was prevented. Thereafter, while the temperature was falling (C in the figure), the gas path was switched by the valve 13 and air containing water vapor was introduced into the panel through the water bubbling device 14 until the sealing was completed.

The timing (C in the figure) for introducing the air containing water vapor into the panel is preferably 100 ° C. or more and 350 ° C. or less for the same reason as in the first embodiment.

When the partial pressure of water vapor in the air containing water vapor was 1.3 kPa (10 Torr) or more, the discharge voltage was significantly reduced.

In the second embodiment, the blue light emission characteristics are improved and the discharge voltage is reduced at the same time by introducing dry air before introducing the air containing water vapor into the panel. When it is not introduced, although the emission characteristics are similar to those of the conventional blue light emission characteristics, it was effective in lowering the discharge voltage.

This is the same in the first embodiment.

Further, in the present embodiment, the glass tube 10
Water vapor was forcibly introduced into the PDP through the
It was also effective to change the atmosphere around P (the atmosphere in the sealing furnace 15 in the present embodiment) to a gas atmosphere containing water vapor during the temperature drop (C in the figure). This is PDP
Vapor in the atmosphere around the PD
It is considered that the gas naturally substitutes for the gas inside P and enters the inside of the PDP. However, in this case, in order to have sufficient replacement,
A longer time was required than in the case where steam was forcibly introduced into the PDP.

After the sealing was completed, the inside of the PDP was evacuated from the glass tube 10, and then a discharge gas was introduced to seal the glass tube to complete the panel.

It should be noted that BaM which is often used in PDPs
gAl ₁₀ O ₁₇ : Eu, Zn ₂ SiO ₄ : Mn or (Y, G
d) When an oxide-based phosphor such as BO ₃ : Eu is heated in an oxygen-free atmosphere, some oxygen vacancies are formed and the luminous efficiency may be reduced. Therefore, it is desirable that the gas used in the sealing step contains at least oxygen.

(Example)

[0057]

[Table 1]

The PDPs of panel numbers 1 to 4 are PDPs according to the examples manufactured based on the first embodiment, and after the sealing step, the panel heating temperature after introducing steam into the internal space was changed. PDP.

The PDPs of panel numbers 5 to 7 are PDPs according to the examples manufactured based on the second embodiment, and have a temperature at which the gas introduced into the panel is switched from a dry gas to a gas containing water vapor. (P in FIG. 7).

Further, the PDP of panel number 8 is a panel in which dry air is flowed in the panel from the start to the end of sealing without introducing air containing water vapor into the panel in the second embodiment. The PDP of panel number 9 is the PDP of the conventional example according to the comparative example.

The panels are 42 "size.

In the first and second embodiments (panel numbers 1 to 7), air containing water vapor having a partial pressure of water vapor of 1.6 Pa (12 Torr) was used as the gas containing water vapor introduced into the panel.

The peak sealing temperature (B in FIG. 7) in Embodiment 2 was set to 450 ° C.

In each of the PDPs, the sealing step was performed with a temperature profile in which the peak temperature was maintained for 20 minutes. Also,
The panel configuration is all the same, and the phosphor film thickness is 30μ.
m, discharge gas is Ne (95%)-Xe (5%).
It was sealed at 5 kPa (500 Torr).

The characteristics evaluated by lighting the panel include the emission intensity of blue (a value obtained by dividing the luminance by the chromaticity coordinate y), the chromaticity coordinate y, and the discharge voltage (the entire panel is lit when displaying white). Minimum voltage). The blue light emission intensity is shown as a relative light emission intensity with the panel number 9 of the comparative example being 100.

From the comparison of the characteristics evaluation of the discharge voltage, it is possible to lower the discharge voltage as compared with the conventional panel by introducing steam into all the panels. The discharge voltage decreases as the temperature at the time of introduction of water vapor increases, whereas when it is too high, the blue light emission characteristics decrease. However, as shown in this example, at 350 ° C. or lower, blue did not particularly deteriorate.

The reason why the discharge voltage decreases as the temperature when the steam is introduced becomes higher as the temperature is increased is that the steam reacts with the MgO by increasing the temperature, and water remains partially in the panel even after the subsequent exhaust process. It is thought to be easier.

Further, the second embodiment (panel numbers 5 to 5)
As shown in 7), it was confirmed that by introducing a dry atmosphere into the panel in the first half of the sealing, both the improvement of the blue light emission characteristics and the improvement of the discharge voltage can be realized.

Although the surface discharge type PDP has been described in the above embodiments, the present invention can be applied to a counter discharge type PDP.

[0070]

As described above, according to the method of manufacturing a plasma display panel having the structure of the present invention, it is possible to lower the discharge voltage. In addition, it is possible to suppress the deterioration of the light emission characteristics of the phosphors generated during the conventional sealing process and to lower the discharge voltage, resulting in a plasma display panel with high light emission intensity and light emission efficiency and a wide color reproduction range. it can.

[Brief description of the drawings]

FIG. 1 is a diagram showing a manufacturing method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the dependency of a change in the relative emission intensity of a blue phosphor on water vapor partial pressure during heating.

FIG. 3 is a diagram showing the dependency of a change in the blue phosphor CIE chromaticity y on the partial pressure of water vapor during heating.

FIG. 4 is a diagram showing a relationship between a relative emission intensity of a blue phosphor of a PDP and a discharge voltage.

FIG. 5 is a diagram showing a heating temperature dependency of a change in relative emission intensity of a blue phosphor.

FIG. 6 is a view showing a sealing method according to a second embodiment of the present invention.

FIG. 7 is a view showing a sealing temperature profile according to a second embodiment of the present invention.

FIG. 8 is a schematic sectional view of an AC surface discharge type plasma display panel according to the present embodiment.

FIG. 9 is a schematic sectional view of a conventional AC surface discharge type plasma display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front plate 2 Back plate 3 Heating furnace 4 Glass tube 5 Dry air cylinder 6 Flow controller 7 Bubbling device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 9/38-9/395 H01J 11/00-17/49

Claims (12)

(57) [Claims] 1. Production of a plasma display panel having a sealing step of overlapping and sealing a front substrate and a rear substrate on each of which a phosphor is disposed on at least one such that an internal space is formed between the two substrates. A method for manufacturing a plasma display panel, comprising a step of introducing steam into the internal space after the sealing step. 2. After the sealing step, the temperature is 100 ° C. or more and 35 ° C.
2. The method of manufacturing a plasma display panel according to claim 1, further comprising the step of heating the plasma display panel to a temperature of 0 ° C. or less to introduce water vapor into the internal space. 3. The method according to claim 1, further comprising, after the sealing step, a step of flowing a gas containing at least water vapor into the internal space. 4. The method according to claim 1, further comprising a step of exposing the plasma display panel to a gas atmosphere containing at least water vapor after the sealing step.
A manufacturing method of the plasma display panel according to the above. 5. In the step of introducing steam into the internal space, the partial pressure of steam in the internal space is set to 1.3 kPa (1 kPa).
Method of manufacturing a plasma display panel according to any one of claims 1 to 4, characterized in that the 0 Torr) or more. 6. Production of a plasma display panel having a sealing step of overlapping and sealing a front substrate and a rear substrate on each of which a phosphor is disposed on at least one of them so that an internal space is formed between the substrates. The method of manufacturing a plasma display panel, wherein, in the sealing step, water vapor is introduced into the internal space when the temperature of the plasma display panel drops to a peak temperature after the plasma display panel is heated to a peak temperature. 7. The method of manufacturing a plasma display panel according to claim 6, wherein after the plasma display panel is heated to a peak temperature, the temperature is decreased to a temperature of 350 ° C. or lower, and then water vapor is introduced into the internal space. 8. The plasma according to claim 6, wherein in the sealing step, when the temperature of the plasma display panel is decreased to a peak temperature after the plasma display panel has been cooled, a gas containing at least water vapor flows in the internal space. Display panel manufacturing method. 9. The method according to claim 6, wherein in the sealing step, when the temperature of the plasma display panel is decreased after being heated to a peak temperature, an atmosphere around the plasma display panel is filled with a gas containing at least water vapor. 8. The method for manufacturing a plasma display panel according to item 7. 10. The plasma display panel according to claim 6, wherein in the sealing step, a dry gas is introduced into the internal space at least until the plasma display panel is heated to a peak temperature. Method. 11. When water vapor is introduced into the internal space when the temperature drops, the partial pressure of water vapor in the internal space is reduced to 1.3 kPa (1 kPa).
The method for manufacturing a plasma display panel according to any one of claims 6 to 10 , wherein the pressure is 0 Torr or more. 12. A plasma display panel manufactured by the manufacturing method according to claim 1.