JP3199069B1 - 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 the emission intensity and chromaticity of a blue phosphor are less reduced and the discharge voltage is lower. SOLUTION: After a sealing step and a vacuum evacuation step, a discharge gas containing water vapor is introduced into a discharge space in a panel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A conventional plasma display panel will be described below with reference to the drawings. FIG. 6 is a cross-sectional view schematically showing an AC type (AC type) plasma display panel.

In FIG. 6, reference numeral 41 denotes a front glass substrate, on which a display electrode 42 is 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)} BO
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 method of manufacturing a PDP 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. A voltage is applied to an electrode to generate glow discharge, thereby generating ultraviolet rays from Xe to excite the phosphor to emit 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 plasma display panel according to the present invention comprises an electrode and a phosphor layer between a pair of parallel plates, and a gas medium. A plasma display panel in which an enclosed discharge space is formed, wherein the gas medium contains at least water vapor.

The gas medium includes at least helium,
One or two of neon, xenon, and argon
It is preferable to include more than one kind of rare gas.

The gaseous medium contains water vapor at 0.0%.
It is preferable that the content is 1% by volume or more and 1% by volume or less.

Further, it is preferable that the plasma display panel is sealed in a state where a dry gas is brought into contact with the phosphor layer.

In the method of manufacturing a plasma display panel according to the present invention, an electrode and a phosphor layer are arranged between a pair of parallel plates, a gas medium is sealed, and a discharge space is formed. A method for manufacturing a plasma display panel, comprising a step of introducing a gas medium containing at least water vapor into the discharge space and sealing the panel.

Further, the image display device of the present invention is characterized by comprising the plasma display panel and a drive circuit for driving the plasma display panel.

[0024]

(Embodiment) Hereinafter, a plasma display panel according to an embodiment of the present invention will be described. FIG. 1 is a sectional view schematically showing an AC surface discharge type plasma display panel according to an embodiment of the present invention. Although only one cell is shown in FIG. 1,
Many cells that emit red, green, and blue light are arranged and PD
P is configured.

This PDP comprises a display electrode 22, a dielectric glass layer 23, 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.

The charging pressure of the discharge gas is a conventional general charging pressure (13.3 kPa (100 Torr) to 80 kP).
a (600 Torr)).

As a discharge gas to be filled, helium (He) such as conventional helium-xenon type or neon-xenon type, or neon (N
e), a mixture of a rare gas containing xenon (Xe) and argon (Ar), and a mixture having a gas composition obtained by further mixing steam.

Here, the content of water vapor is 0.01% by volume.
Above, it is preferable to be 1% by volume or less. As a specific example of the gas composition, Ne (94.9%)-Xe (5%)-
A gas composition of H ₂ O (0.1%) can be mentioned (note that “%” in the gas composition formula represents volume%; the same applies hereinafter).

By setting the composition of the discharge gas as described above, the discharge voltage can be greatly reduced as compared with the conventional one, as described later.

FIG. 2 and FIG. 3 show that when the used blue phosphor (BaMgAl ₁₀ O ₁₇ : Eu) was fired 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, and the chromaticity coordinate y 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 process for sealing the front plate and the back plate is narrower than that of the phosphor baking process or the low-melting glass paste calcining process. 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 panel, the phosphor layer formed on the rear panel, or the low-melting glass paste for sealing during heating is greatly increased. It is important that the atmosphere in the panel in the sealing step be a dry atmosphere. In this embodiment, the sealing is performed by changing the atmosphere around the phosphor layer to a dry gas during the sealing step. Was.

However, as for the discharge voltage, the discharge voltage tends to increase as the atmosphere during the sealing step is changed to a dry atmosphere (ie, as the deterioration of the blue phosphor is prevented).

FIG. 4 shows the blue light emission intensity and discharge voltage of a PDP produced by changing the partial pressure of water vapor in the panel during the sealing step. Here, the discharge voltage is a minimum voltage necessary for lighting the PDP in white display on the entire surface. The data in FIG. 4 indicate that the partial pressure of water vapor during the sealing step was reduced toward the right side, and it was found that the emission intensity increased along with this, but the discharge voltage also increased. From this result, the more moisture remaining in the PDP after the sealing step,
It is considered that the discharge voltage decreases.

Therefore, in order to reduce the discharge voltage while suppressing the deterioration of the blue phosphor during the sealing step, water vapor is mixed with the discharge gas introduced after the sealing step and the evacuation step, and the water vapor is forcibly removed from the PDP. Introduced inside.

In the present embodiment, the blue phosphor is sealed in a dry atmosphere in order to suppress the deterioration of the blue phosphor during the sealing step.
Even when a discharge gas containing water vapor is introduced after evacuation, there is an effect of reducing the discharge voltage.

As shown in FIG. 5, an image display device is manufactured by connecting each driver and the panel driving circuit 100 to the PDP, and when driving the PDP, the scanning electrode 101a and the address electrode of the cell to be turned on are driven. After the address discharge is performed by applying the voltage between the display electrodes 102a, the display electrodes 101a, 10a
A sustain voltage is applied by applying a pulse voltage between 1b. Then, the cell emits ultraviolet light in accordance with the discharge, and is converted into visible light by the phosphor layer. An image is displayed by lighting the cell in this manner.

[0040]

【Example】

[0041]

[Table 1]

Table 1 shows the characteristics of each panel in this embodiment.

The PDPs of panel numbers 1 to 5 are PDPs according to the examples manufactured based on the above embodiment,
Panels 1 to 4 are sealed while keeping the inside of the panel in a dry atmosphere, and 5 is a panel sealed by a conventional method. A gas containing steam is introduced as a discharge gas, and the content of steam in the panel is changed. PDP.

The PDP of panel No. 6 is a panel in which a conventional discharge gas (mixed gas of Ne and Xe) containing no water vapor is introduced into a panel sealed in a dry atmosphere in the panel. The PDP No. 7 is a PDP according to a comparative example manufactured by a conventional method.

The water vapor content of the discharge gas in the panel was measured by a quadrupole mass spectrometer after the panel was evaluated for lighting and the discharge gas in the panel was taken out by breaking the panel. Also in the panels (Panel Nos. 6 and 7) in which the conventional discharge gas containing no water vapor was introduced into the panel, water and the like adsorbed inside the panel were partly desorbed and contained in the discharge gas (however, <0.01%).

The panels are 42 "in size.

In each of the above PDPs, the panel configuration is all the same, and the thickness of the phosphor is 30 μm. As the discharge gas, a discharge gas of Ne (95%)-Xe (5%) or a discharge gas in which Ne (95%)-Xe (5%) contains steam at an arbitrary value is used. .
The pressure was set to 5 kPa (500 Torr).

The characteristics evaluated by lighting the panel include the emission intensity of blue (the 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 7 of the comparative example being 100.

From the comparison of the characteristics 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 was lowered as the content of water vapor was increased. On the other hand, when the voltage was too high, the discharge was unstable in the panel due to dew condensation and abnormal discharge. Therefore, the water vapor content of the discharge gas in the panel is 0.01% by volume.
As mentioned above, 1% by volume or less was preferable.

It was confirmed that both the improvement of the blue light emission characteristics and the improvement of the discharge voltage can be realized by introducing a discharge gas containing water vapor after sealing the panel in a dry atmosphere as in this embodiment. did it.

In the above embodiment, Ne-X
e-type gas containing water vapor was used.
Similar effects were obtained in all cases where a rare gas discharge gas composed of e, Ne, Xe, Ar, or the like was used.

Further, in the above embodiment, the surface discharge type PDP is exemplified. However, the present invention can be applied to a counter discharge type PDP and the like, and the same effect can be obtained.

[0053]

As described above, according to the plasma display panel of the present invention, the discharge voltage can be reduced. 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 schematic sectional view of an AC surface discharge type plasma display panel according to the present embodiment.

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 an image display device in which a driving circuit is connected to the PDP of the present embodiment.

FIG. 6 is a schematic sectional view of a conventional AC surface discharge type plasma display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Front glass substrate 22 Display electrode 23 Dielectric glass layer 24 Protective layer 25 Back glass substrate 26 Address electrode 27 Visible light reflective film 28 Partition wall 29 Phosphor layer

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-9-245653 (JP, A) JP-A-49-53761 (JP, A) JP-A-11-120920 (JP, A) 5014 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 11/00-11/04 H01J 17/00-17/49

Claims (7)

(57) [Claims] 1. A method according to claim 1, further comprising the steps of:
There is provided a plasma display panel in which an electrode and a phosphor layer are provided and a discharge space in which a gas medium is sealed is formed .
A plasma display panel characterized by being contained in an amount of from 01% by volume to 1% by volume . 2. The plasma display panel according to claim 1, wherein the gas medium contains at least one or two or more rare gases of helium, neon, xenon, and argon. Wherein the plasma display panel, a plasma display panel according to any one of claims 1-2, characterized in that it is sealed in a state contacting the dry gas to the phosphor layer. 4. Between a pair of parallelly arranged plates,
A method for manufacturing a plasma display panel in which an electrode and a phosphor layer are provided and a discharge space in which a gas medium is sealed is formed, wherein at least the discharge space includes
A method for manufacturing a plasma display panel, comprising a step of introducing a gas medium containing water vapor of 0.01% by volume or more and 1% by volume or less to seal the panel. 5. The gas medium includes at least helium,
One or two of neon, xenon, and argon
6. The gas according to claim 5, wherein at least one kind of rare gas is contained.
A manufacturing method of the plasma display panel according to the above. 6. The method for manufacturing a plasma display panel according to claim 4 , wherein said plasma display panel is sealed in a state in which a dry gas is brought into contact with said phosphor layer. 7. An image display apparatus comprising: the plasma display panel according to any one of claims 1 to 3, a driving circuit for driving the plasma display panel.