JP3220081B2 - Plasma display panel - Google Patents

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 used for a color television receiver or display for displaying characters or images.
Panel, hereinafter referred to as “PDP”. ).

[0002]

2. Description of the Related Art In recent years, expectations for high-definition and large-screen televisions such as high-definition televisions have been increasing.
In various fields such as RT and liquid crystal display panel (hereinafter, referred to as LCD), a display suitable for this is being developed.

First, a CRT that has been widely used as a display panel of a television can be considered. A CRT is superior to a PDP or a liquid crystal in terms of resolution and image quality, but is inferior in depth and weight. Not suitable for large screens of 40 inches or more. In addition, the liquid crystal has excellent performance such as low power consumption and low driving voltage, but there are limitations on the size of the screen and the viewing angle.

On the other hand, the PDP can realize a large screen with a small depth, and a 40-inch class product has already been developed.

[0005] The PDP is roughly classified into a direct current type (DC type) and an alternating current type (AC type) according to a driving method. In the DC type, generally, electrodes are exposed to a discharge space and partition walls are formed in a grid shape. On the other hand, in the AC type, a dielectric glass layer is disposed on the electrode and the partition walls are formed in a stripe shape, which is a structure suitable for forming a fine cell structure.

FIG. 9 is a schematic sectional view showing an example of an AC type (AC type) PDP.

In FIG. 9, reference numeral 61 denotes a front glass substrate, on which a display electrode 62 is provided, on which a dielectric glass layer 63 and a dielectric protection layer made of magnesium oxide (MgO) are formed. 64 (see, for example, JP-A-5-342991).

Reference numeral 65 denotes a rear glass substrate, and address electrodes 66...
And the partition walls 67 are provided in a stripe shape.
A phosphor 68 is provided in a recess between the partition 7 and the partition 67. The phosphor 68 includes a red phosphor layer 68R, a green phosphor layer 68G, and a blue phosphor layer 68 for color display.
In this configuration, three colors B are arranged in order. Further, a discharge gas is sealed in the concave portion to form a discharge space 69.

The principle of light emission of a PDP is basically the same as that of a fluorescent lamp, and ultraviolet rays are emitted from a discharge gas upon discharge, and phosphor particles (red, green, blue) of a phosphor layer emit the ultraviolet rays. Upon receiving and exciting light emission, it is difficult to obtain a high luminance like a fluorescent lamp because the efficiency of converting discharge energy to ultraviolet light and the efficiency of converting phosphor into visible light are low.

[0010]

As the demand for a high-quality display increases, it is desired to use a fine cell structure in a PDP, but the radiation efficiency of ultraviolet rays becomes worse as the discharge space becomes smaller. In order to put a PDP having a detailed cell structure into practical use, it is necessary to further increase the luminous efficiency as compared with the related art.

For example, in the conventional NTSC, the number of cells is 64.
It is 0x480, and the cell pitch is 0.4 in the 40-inch class.
43mm x 1.29mm, cell area is about 0.55mm
² , the brightness of the panel is about 250 cd / m ² (for example,
Functional Materials, February 1996, Vol. 16, No. 2, page 7).

On the other hand, at the pixel level of a full-spec high definition television, the number of pixels is 1960 × 112.
5 and the cell pitch in the 42-inch class is 0.15
mm × 0.48 mm, the area of one cell is 0.072 mm ²
It becomes fine. When a PDP for a 42-inch high-definition television is manufactured with the same cell configuration as the conventional one, the panel luminous efficiency becomes 1/7 that of the case of NTSC.
About 1/8, and it is reduced to about 0.15 to 0.17 lm / W.

The present invention has been made under such a background, and provides a PDP capable of operating with high luminous efficiency even in a fine cell structure by increasing the luminous efficiency as compared with the related art. The purpose is to do.

[0014]

In order to achieve the above object, a front cover plate having a first electrode disposed on a surface thereof and a back plate having a second electrode disposed on a surface thereof are provided. The first and second electrodes are arranged facing each other with an interval therebetween, and the gap between the two plates is partitioned by a partition, and a phosphor layer is disposed in a space partitioned by the partition. In a plasma display panel in which a dischargeable gas medium is sealed in the remaining space, the phosphor layer extends over the surface of the back plate, the wall surface of the partition wall, and the surface of the front cover plate. In addition, the porosity (filling rate) of the phosphor layer in the front cover plate is larger (smaller) than the porosity (filling rate) of the phosphor layer in the back plate and the partition. It is characterized in.

The average particle size is A, and the weight ratio is 10% or less.
The maximum particle size in the range of 90% is dmax, and the minimum particle size is dmin.
When x represented by x = 100 · A / (A + dmax−dmin) is defined as a particle concentration (%), the phosphor layer in the front cover plate is formed of phosphor particles used to form the phosphor layer. The particle size concentration is larger than the particle size concentration of the phosphor particles used for forming the phosphor layer on the back plate and the partition.

Here, the particle size concentration x of the phosphor particles used to form the phosphor layer on the front cover plate
Is desirably 50% or more.

Further, it is more preferable that the concentration x of the particle diameter of the phosphor particles used for forming the phosphor layer in the front cover plate is 80% or more.

Further, it is desirable that the particle diameter concentration x of the phosphor particles used for forming the phosphor layer on the back plate and the partition wall is less than 50%.

Further, the distance from the center point of the phosphor particles to the farthest point on the particle surface is a, and the distance from the closest point to the closest point is c.
When c / a is defined as the sphericity of the particles, the sphericity of the phosphor particles used for forming the phosphor layer on the front cover plate is determined by the fluorescence used for forming the phosphor layers on the back plate and the partition walls. The above object can be achieved even with a PDP having a sphericity greater than that of body particles.

Here, it is more desirable that the phosphor layer in the front cover plate is formed except for a region corresponding to the first electrode.

In addition, the pressure at which the gas medium is filled is 760-760.
It is more desirable to set it to 4000 Torr.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a P according to an embodiment of the present invention will be described.
The DP will be specifically described with reference to the drawings.

FIG. 1 shows an AC surface discharge type PD according to this embodiment.
It is a perspective view which shows the outline of P.

FIG. 2 is a sectional view taken along line XX of FIG. 1, and FIG. 3 is a sectional view taken along line YY of FIG.

This PDP comprises a front panel (front cover plate) 10 in which display electrodes (discharge electrodes) 12, a dielectric glass layer 13, and a protective layer 14 are disposed on a front glass substrate 11, and a rear glass substrate 21. Address electrode 2
2. A back panel (back plate) 20 on which a visible light reflecting layer 23 is disposed is disposed in parallel with each other at an interval with the display electrode 12 and the address electrode 22 facing each other,
The gap between the front panel 10 and the rear panel 20 is
Are formed and cell spaces 40 are formed, and the space 40 is filled with a discharge gas. In the cell space 40, a first phosphor layer 31 is provided on the front panel 10 side, and a second phosphor layer 32 is provided on the back panel 20 side.

The display electrode 12 and the address electrode 22 are both stripe-shaped silver electrodes, and are arranged in a direction forming an orthogonal matrix.

The dielectric glass layer 13 is formed on the front glass substrate 1.
Cover the entire surface on which one display electrode 12 is disposed, and have a thickness of 20 μm.
It is a layer made of lead glass or the like having a thickness of about the same.

The protective layer 14 is made of magnesium oxide (Mg)
O), which covers the surface of the dielectric glass layer 13.

The visible light reflecting layer 23 is formed on the back glass substrate 21.
Is a layer made of a dielectric glass (lead glass) containing titanium oxide, which has both a visible light reflecting function and a function as a dielectric layer.

The partition 30 protrudes from the surface of the visible light reflecting layer 23 of the back panel 20 and is formed in a stripe shape along the address electrode 22.

[Shape and Light Emitting Function of Phosphor Layer] In each cell, the first phosphor layer 31 is uniformly formed on substantially the entire surface of the protective layer 14 on the front panel 10. However, as shown in FIG. 3, the portion on the surface of the display electrode 12 is notched (14a in FIG. 3).

If the notch 14a is provided as described above, the surface of the protective layer 14 is exposed to the discharge space at this location, so that the discharge of the display electrode 12 to the discharge space by the phosphor layer is prevented by the phosphor layer during PDP driving. It is done without being done.

The ions generated during the discharge in the discharge space move toward the display electrode 12, so that the notch 1
In portions other than 4a, the ion bombardment applied to the phosphor layer at the time of discharge is not large. However, if there is a phosphor layer in the notch 14a, the portion is liable to deteriorate with time due to ion bombardment. Therefore, if the notch 14a is provided as described above, the deterioration of the phosphor layer over time can be suppressed, and the deterioration of the luminous efficiency over time can be suppressed.

On the other hand, as shown in FIG. 2, the second phosphor layer 32 is provided between the partition 30 on the back panel 20 and the surface of the visible light reflecting layer 23 and the side of the partition 30. Formed over.

More specifically, the second phosphor layer 32 has a rear surface formed along the surface of the rear glass substrate 21 so that the surface area of the phosphor layer is large and the volume of the discharge space is large. 32a and a side surface 32b formed along the surface (wall surface) of the partition 30.

Next, in the PDP of the present embodiment,
The reason why the luminous efficiency can be improved as compared with the conventional example as shown in FIG. 9 will be described with reference to FIG.

At the time of driving the PDP, ultraviolet light is generated in the discharge space along with the discharge between the display electrodes 12. The ultraviolet light is directed toward the first phosphor layer 31 (open arrow U1 in FIG. 2) and the ultraviolet light is directed toward the second phosphor layer 32 (open arrow in FIG. 2). U2). The first phosphor layer 31 functions to convert the former ultraviolet light U1 to visible light, and the second phosphor layer 32 functions to convert the latter ultraviolet light U2 to visible light.

The visible light converted by the second phosphor layer 32 that passes through the first phosphor layer 31 and the front panel 10 (thick arrow V2 in FIG. 2) and the first phosphor Layer 31
It is conceivable that two of the visible lights that have passed through the front panel 10 and that pass through the front panel 10 (thick arrow V1 in FIG. 2) mainly contribute to the luminance of the panel.

That is, when no phosphor layer is provided on the front glass substrate 61 side as in the conventional example of FIG. 9, the ultraviolet rays U1 generated by the discharge escape to the front panel side. When the first phosphor layer 31 exists as in the embodiment, the ultraviolet light U1 is converted into the visible light V1.
Since 1 occurs, the luminous efficiency improves accordingly.

However, if the visible light transmittance of the first phosphor layer 31 is small, the visible light V2 generated in the cell cannot be effectively taken out. It is necessary to set the visible light transmittance of No. 31 in an appropriate range.

The preferable conditions for improving the luminous efficiency are considered as follows. First, when the first phosphor layer 31 and the second phosphor layer 32 are compared, the first phosphor layer 31 needs to transmit visible light as described above, whereas the second phosphor layer 31 does not. Since the phosphor layer 32 does not need to transmit visible light, the average visible light transmittance of the first phosphor layer 31 is set to be larger than the average visible light transmittance of the second phosphor layer 32. Is preferred.

To set the relationship of the visible light transmittance as described above, the filling rate d1 of the phosphor particles of the first phosphor layer 31 (the volume ratio occupied by the phosphor particles per unit space)
May be set smaller than the filling rate d2 of the second phosphor layer 32 (that is, d1 <d2). This means that there is a correlation between the filling rate and the visible light transmittance, and the smaller the filling rate, that is, the larger the porosity between the phosphor particles, the larger the visible light transmittance. Based on knowledge. In particular, the filling rate d1 of the first phosphor layer 31 is preferably set so that the visible light transmittance is 50% or more. In the side surface portion 32b, the higher the visible light reflectance of the portion, the higher the amount of light incident on the first phosphor layer. Therefore, the filling ratio of the portion is set to be larger than that of the back surface portion 32a. It is desirable to do.

The second phosphor layer 32 is considered as follows.

In the second phosphor layer 32, the first phosphor layer 31 is used to reflect the generated visible light to the front panel side.
It is desirable to set the filling rate of the phosphor particles to be larger than that of the first phosphor layer 31. Here, if the amount of visible light incident on the first phosphor layer 31 is increased to improve the panel luminance, the visible light is increased. It is preferable to set the light transmittance to less than 50%. Further, when the second phosphor layer 32 is described in detail, the visible light reflecting layer 23
Is formed, it is easy to secure the emission amount of the visible light V2 even if the visible light transmittance is relatively high.
In 2b, since there is no visible light reflecting layer 23 below, it is difficult to secure the generation amount of visible light V2 unless the visible light transmittance is low. Therefore, it is preferable to set the thickness of the side surface portion 32b to be larger than that of the back surface portion 32a even if the filling ratio is the same so that the visible light transmittance is slightly lower than that of the back surface portion 32a.

In this embodiment, the visible light reflecting layer 2
3 is provided, but in a configuration where the visible light reflecting layer 23 is not provided (for example, when a normal dielectric glass layer is provided instead of the visible light reflecting layer 23, In the case where the second phosphor layer is directly disposed on the rear glass substrate 21), it is preferable that the thickness of the portion along the rear glass substrate 21 is set to be as thick as the above-mentioned side portion.

[Composition of discharge gas and sealing pressure]
As the discharge gas, a gas having a gas composition such as a helium-xenon system or a neon-xenon system which has been conventionally used can be used. In the present embodiment, helium (H) is used.
e), a mixture of a rare gas containing neon (Ne), xenon (Xe), and argon (Ar) is used. By using a discharge gas having such a composition, the luminous efficiency can be improved and the discharge voltage can be reduced.

Here, it is preferable that the content of xenon is 5% by volume or less, the content of argon is 0.5% by volume or less, and the content of helium is less than 55% by volume.

The charging pressure of the discharge gas is set at 500 to 4000 Torr, which is higher than the conventional general charging pressure. Such a high charging pressure also contributes to the improvement of the luminous efficiency. In particular, 760-4 above atmospheric pressure
It is preferable to set it in the range of 000 Torr in order to obtain high luminous efficiency.

However, since the discharge starting voltage increases with an increase in the filling gas pressure, setting the filling pressure in the vicinity of 1000 to 2000 Torr is considered to be the best for panel characteristics.

When the sealing pressure is set to a high value as described above, the energy of ions generated during the discharge decreases, so that the first phosphor layer 31 is prevented from deteriorating with time and the luminance of the panel is reduced. It also has the effect of suppressing.

[Method of Manufacturing PDP] The PDP having the above structure can be manufactured as follows.

Front panel: On the front glass substrate 11, first, a display electrode 12 is formed in a stripe shape by applying a silver electrode paste by screen printing and then baking.

Then, lead glass is applied to the entire surface of the front glass substrate 11 on which the display electrodes 12 are formed by a screen printing method and is baked, whereby the dielectric glass layer 13 is formed.
To form

Next, the entire surface of the dielectric glass layer 13 is
The front panel is manufactured by forming the protective layer 14 of magnesium oxide using a CVD method (chemical vapor deposition method).

In the formation of the protective layer by the CVD method,
A glass substrate is set in a CVD apparatus, and a magnesium compound and oxygen as a source are fed into the glass substrate and reacted to form a magnesium oxide layer on the substrate. Examples of sources for use herein include acetylacetone magnesium _{[Mg (C 5 H 7 O} 2) 2], cyclopentadienyl magnesium _{[Mg (C 5 H 5)} 2]
Can be mentioned.

Preparation of rear panel: Address electrodes 22 are formed in a stripe shape on the rear glass substrate 21 by screen-printing a paste for a silver electrode and then firing.

Then, a dielectric glass containing titanium oxide particles is applied by a screen printing method on the surface of the rear glass substrate 21 on which the address electrodes 22 are formed, and is baked to form the visible light reflecting layer 23. And back panel 2
0 is produced.

As a method for forming the visible light reflecting layer 23, it is also possible to first form a partition on the surface of the rear glass substrate and then apply an ink containing titanium oxide between the partitions.

Formation of Partition Wall and Phosphor Layer; Back Panel 20
On the visible light reflecting layer 23, a partition wall material made of glass is repeatedly applied in a stripe shape at a predetermined interval by a screen printing method, and then baked to form the partition wall 30.

A first phosphor layer 31 is formed by applying red, green, and blue phosphors to a predetermined region on the protective layer 14 of the front panel 10 and performing baking.

As the phosphor of each color, a phosphor generally used in a PDP can be used. Here, as the red phosphor, (Y _x Gd _{1 -x} ) BO ₃ : E
u ³⁺ , Zn ₂ SiO ₄ : Mn as the green phosphor, and BaMgAl ₁₀ O ₁₇ : Eu ²⁺ as the blue phosphor.

As a method for applying the phosphor, there is a method using a photolithography technique commonly used in the production of semiconductors, in addition to a method for applying the phosphor ink by a screen printing method.

That is, a phosphor paste in which a phosphor is kneaded in a photosensitive resin is applied to the entire surface, and then patterning is performed by photolithography in order for each color. Layers can also be formed.

In the case of a high-definition panel structure, it is difficult to obtain sufficient precision by the screen printing method and color mixing may occur. Can be formed.

On the other hand, inks or pastes containing red, green and blue phosphors are applied to the recesses formed between the partitions 30 on the rear panel 20 and fired by firing. Is formed. The phosphor used here is the same as that used for the first phosphor layer 31.

When the phosphor is applied to the concave portions between the partition walls 30, each of the phosphor on the bottom surface of the concave portion (ie, on the surface of the visible light reflecting layer 23) and on the side surface of the concave portion (ie, on the side surface of the partition wall 30). Then, coating is performed so that the phosphor adheres with an appropriate film thickness.

In some cases, such a phosphor can be applied by a screen printing method using a phosphor paste. However, in the case of the screen printing method, it is difficult to attach the phosphor paste to the side wall of the concave portion. It is difficult in the case of a detailed cell structure.

On the other hand, using the ink filling device as shown in FIG. 4, the nozzle is scanned along the partition wall while projecting the phosphor ink from the nozzle to crosslink the phosphor ink as follows. If the coating is performed by the method, the phosphor ink can be relatively easily attached to the side wall of the concave portion.

In the ink filling device 50 shown in FIG. 4, the phosphor ink is fed into the header 51 from a pressure pump (not shown) and projected from the nozzle 52.

Using this ink filling device 50, the distance between the nozzle 52 and the side surface of the partition wall 30 is made sufficiently close to the phosphor ink to be crosslinked by surface tension while projecting the phosphor ink from the nozzle 52. The phosphor ink is applied to the recesses between the partitions 30 by scanning the header 51 along the partitions 30.

According to this method, the phosphor ink can be easily attached not only to the bottom surface of the concave portion but also to the side surface of the partition wall 30.

The shape of the phosphor layer to be formed (the ratio of the thickness of the bottom surface to the side surface of the recess) is determined by the fluorescence between the bottom surface of the recess (the surface of the visible light reflecting layer 23) and the surface of the partition wall 30. The shape of the phosphor layer to be formed can be adjusted by adjusting the surface state, since the shape is greatly influenced by the attraction force to the body ink.

FIG. 5 shows an example of a state in which the phosphor ink filled in the concave portion between the partition walls 30 dries.
(A) immediately after phosphor ink application, (b) during drying,
(C) shows the state after drying.

For example, when forming the partition 30, the material of the partition is selected so that the contact angle of the phosphor ink with respect to the side surface of the partition 30 is smaller than the contact angle of the phosphor ink with the visible light reflecting layer 23. If this is done, as shown in this figure, when the phosphor ink applied to the concave portion between the partition walls 30 dries, a large amount of the phosphor ink adheres to the side surface of the concave portion and remains.
The thickness on the side surface of the concave portion can be increased, and the thickness on the bottom surface can be reduced.

As described above, the phosphor layers are laid such that the filling rate of the first phosphor layer 31 is smaller than the filling rate of the second phosphor layer 32. In the present embodiment, Each phosphor layer is formed by using phosphors having different particle size distributions or using phosphors having different particle shapes.

That is, although there may be some indexes of the particle size distribution, here, the particle size concentration x represented by the following formula 1 is used, and the phosphor particles having a large value are used as the first fluorescent material. For the body layer 31, phosphor particles having a small value are used for the phosphor layer 32. In the present embodiment, the measurement of the particle size is as follows:
A Coulter counter particle size analyzer (a particle size measuring device manufactured by Coulter Corporation) is used.

(Equation 1) x = 100 · A / (A + dmax−dmin) where A: average particle diameter (passage rate (weight ratio) 50)
% Max. Particle size (particle size at 90% pass rate (weight ratio)) dmin; minimum particle size (particle size at 10% pass rate (weight ratio))

FIG. 6 is a schematic diagram two-dimensionally showing the arrangement of particles when a phosphor layer is formed using phosphor particle groups having different particle concentration levels x (%). ) Is a case where a particle group having a large particle size concentration x (%) is used (first phosphor layer 31), and (b) is a case where a particle group having a small particle size concentration (%) is used ( It shows an arrangement state of particles of the second phosphor layer 32). Actually, since the phosphor layer is formed by sintering as described above, the particles have lost their original shape, and it is considered that the arrangement state of the particles before sintering is slightly different, but the arrangement state as shown in the figure is used. Has been confirmed by electron microscope observation.

First, when a particle group having a large particle size concentration x (%) is used, the porosity per predetermined space (in the dotted frame in the figure) is large as shown in FIG. On the other hand, when a particle group having a small particle size concentration x (%) is used, the porosity per predetermined space (in the dotted frame in the figure) is small as shown in FIG. That is, the particle size concentration x
The particles are arranged in a state where the packing ratio d1 when the particle group having a large (%) is used is smaller than the packing ratio d2 when the particle group having a small particle concentration ratio x (%) is used. A particle group having a smaller particle size concentration x (%) has a larger particle size concentration x
Since the ratio of the number of small-diameter particles increases as compared with the case where a particle group having a large (%) is used, the small particles enter the gaps between the large particles, the voids decrease, and the packing ratio increases. . Further, the particle size concentration x (%) effective for improving the brightness of the panel based on the reduction of the filling rate due to the difference in the particle size concentration x (%) may be 50% or more. It has been experimentally confirmed that, even in this range, from the viewpoint of further stabilizing the luminance, it is more preferably 80% or more.

The y value (sphericity) represented by the following equation (2)
Each phosphor layer can also be formed using phosphors having different particle shapes by using as an index.

(Equation 2) y = c / a where c: distance from the center point of the phosphor particles to the closest point on the particle surface a; distance from the center point of the phosphor particles to the farthest point on the particle surface

That is, those having a large sphericity y, that is, particles having a spherical particle shape, are used as the first phosphor layer 31. Those having a small sphericity y, that is, plate-shaped particles having a particle shape deformed from a sphere are also used. Was used to form the second phosphor layer 32. In addition,
In the present embodiment, the measurement of the sphericity is performed by an image processing apparatus using an electron microscope, and based on the result, the fluorescence having the sphericity y value distributed in the range of 0.8 ≦ y ≦ 1.0 is obtained. The body is defined as “spherical”, and the phosphor having a sphericity y value in the range of y <0.8 is defined as “plate-like”.

FIG. 7 shows the arrangement of particles when the phosphor layer is formed using the above-described phosphor particle groups having different degrees of sphericity.
FIG. 4A is a schematic diagram that is dimensionally represented, and FIG. 4A illustrates a case where a particle group having a large sphericity y is used (first phosphor layer 31).
(B) shows the case where a group of particles having a small sphericity y is used (second
Of the phosphor layer 32). In addition, here, actually, since the phosphor layer is formed by firing as described above, the particles have lost their original shapes and are considered to be slightly different from the arrangement state of the particles before firing, but as shown in the figure. It is confirmed by observation with an electron microscope that the alignment state is obtained.

First, when a spherical particle group having a large sphericity y is used, the porosity per predetermined space (within a dotted frame in the figure) is large as shown in FIG. When a plate-like particle group having a small sphericity y is used, the porosity per predetermined space (within the dotted frame in the figure) is small as shown in FIG. That is, the particles are arranged in a state where the filling rate d1 when using the spherical particle group is smaller than the filling rate d2 when using the plate-like particle group.
In the case of the plate-shaped particles, the voids are reduced and the packing ratio is increased because the particles are densely arranged as compared with the case where the spherical particles are used. In addition, such a special phosphor having a large sphericity can be manufactured by applying a method described in, for example, JP-A-62-201989 or JP-A-7-268319. it can.

Further, when a particle group having a large particle concentration x (%) and a large sphericity is used, the porosity is further increased as compared with the case of using a particle group satisfying either one, that is, the packing ratio. Can be reduced.

The filling rate of the phosphor layer can be set low by setting the phosphor concentration of the phosphor paste to be used low. However, in this case, since the amount of the organic binder increases, the firing is not performed. Since there is a possibility that the luminance remains as an impurity even afterwards and panel luminance is deteriorated, the method of setting the filling rate by changing the particle size distribution or changing the particle shape as described above is effective in this regard.
In order to improve the visible light transmittance in this way, besides setting the porosity (filling rate) of the phosphor layer to be large (small), a method of simply reducing the film thickness is also conceivable. When the conversion rate is set, it is preferable that the porosity (filling rate) is formed to be large (small) because the transmittance of visible light is likely to be large. Seem.

Production of PDP by Panel Bonding: The front panel 10 produced as described above and the rear panel provided with the partition 30 are sealed so that the display electrodes 12 and the address electrodes 22 are orthogonal to each other. Along with bonding using glass, the inside of the discharge space partitioned by the partition 30 is
After evacuating to a high vacuum (8 × 10 ⁻⁷ Torr), a discharge gas having a predetermined composition is sealed at a predetermined pressure to form a PD.
Prepare P.

[0088]

[Embodiment 1] The height of the partition wall 30 is set at 0. 4 according to the display of a 42-inch high-definition television.
1 mm, the interval (cell pitch) between the partition walls 30 is 0.15 mm
Based on the above-described embodiment, a PDP having a phosphor formed under several conditions was manufactured, and the above-described effects were verified.

The dielectric glass layer 13 is made of lead oxide [PbO]
70% by weight, 15% by weight of boron oxide [B ₂ O ₃ ] and 15% by weight of silicon oxide [SiO ₂ ] were added to an organic binder (α).
A composition obtained by mixing 10% ethyl cellulose in terpineol) was applied by a screen printing method, followed by baking at 580 ° C. for 10 minutes to form a film having a thickness of 20 μm.

The protective layer 14 is formed by a plasma CVD method.
It was formed to a thickness of 1 μm.

The visible light reflecting layer 23 was formed in the same manner as the dielectric glass layer 13 except that titanium oxide particles were mixed with lead glass.

The phosphor used for the second phosphor layer 32 has a particle concentration concentration of 40%, and the phosphor used for the first phosphor layer 31 has a particle concentration concentration of 30% and 40%. , 50%,
Each of the first and second phosphor layers 31 and 32 contains each phosphor ink containing a phosphor having an average particle diameter of 3 μm, except that the different phosphor inks are different from 60%, 70%, 80% and 95%. It was applied by a screen printing method and fired to form an average thickness of 20. Incidentally, for example, an average particle diameter of 3 μm
The phosphor having a particle size concentration (%) of 50% and a particle size concentration of 50% has a particle size of 1.5 μm at a transmittance of 10% (weight) and a particle size of 4.5 μm at a transmittance of 90% (weight). The phosphor having a particle size concentration (%) of 80% has a particle size of 2.625 μm at a 10% transmittance (weight) and a particle size of 90% at a 90% transmittance (weight). 375 μm.

The composition of the discharge gas to be filled was 500 Torr as a discharge gas using helium (He) gas containing 5% xenon (Xe) gas.

The PDP manufactured as described above was
V, the luminance of the panel when driven at a frequency of 30 KHz was measured, and the first phosphor layer 31 of the front cover plate was measured.
The influence of the particle size concentration (%) used on the luminance on the luminance was examined. In FIG. 8, the results are plotted with the particle diameter concentration (%) of the phosphor used for the first phosphor layer 31 on the horizontal axis and the panel luminance on the vertical axis. In this figure, the panel luminance is
The brightness when the particle size concentration is 30% is set as a reference (100),
It is expressed as a relative value.

As shown in the characteristic diagram, it can be understood that the relative brightness of the panel is improved as the particle concentration degree (%) of the phosphor used for the first phosphor layer 31 is larger. As described above, as the particle size concentration (%) increases, the filling rate of the first phosphor layer 31 decreases and the porosity between the phosphor particles increases, and therefore, the first phosphor layer 31 increases. This is because the amount of visible light transmitted from the light increases.

Further, the relationship between the particle size concentration (%) of the phosphor used for the first phosphor layer 31 and the relative luminance is considered in detail. It can be seen that the effect of improving the panel luminance is small when the value is less than 50%, and a high effect of improving the panel luminance is obtained when the value is 50% or more. From this, it can be said that it is desirable to set the particle size concentration (%) of the phosphor used for the first phosphor layer 31 to 50% or more. However, even if the first phosphor layer 31 has the same visible light transmittance, by further increasing the visible light reflectance on the back plate side, specifically, for example, the second phosphor layer 32 The filling rate is formed densely by using a phosphor having a smaller particle concentration, and the visible light reflectance of the side surface portion 32b is set to be high, so that the amount of visible light incident on the first phosphor layer 31 is increased. Panel luminance can be improved by increasing the amount of visible light transmitted from the first phosphor layer 31. When the particle size concentration (%) is 80 (%) or more, the relative luminance is improved to around 120%, but the rate of change is small. Therefore, in order to reduce the influence of the variation in the particle size distribution of the phosphor used in the first phosphor layer 31 and obtain a more stable and high panel luminance,
It can also be seen that it is preferable to use a phosphor having a particle size concentration (%) of 80 (%) or more.

Example 2 Next, PDPs of panels 1 to 4 as shown in Table 1 were prepared in the same manner as described above, and driven in the same manner as described above to determine the relationship between the particle shape and the panel luminance (relative luminance). Considered.

[0098]

[Table 1]

The panel 1 has the first phosphor layer 31 formed of a plate-shaped phosphor and the second phosphor layer 32 formed of a spherical phosphor, and the panel 2 has the first phosphor layer 31 formed of a spherical phosphor. The panel 31 is formed of a spherical phosphor and the second phosphor layer 32 is formed of a spherical phosphor.
Is a plate-shaped phosphor, the second phosphor layer 32 is formed of a plate-shaped phosphor, and the panel 4 has a structure in which the first phosphor layer 31 is a spherical phosphor and is formed of a second phosphor. The layer 32 is formed of a plate-like phosphor.

In Table 1 above, a comparison between Panel 1 and Panel 2 and between Panel 3 and Panel 4 shows that panel luminance can be improved by using a spherical phosphor for the first phosphor layer. This is because if the first phosphor layer 31 is formed of a spherical phosphor as described above, the filling rate can be reduced and the porosity between the phosphor particles can be increased, so that the visible light transmitted from the first phosphor layer 31 can be reduced. This is because the amount of light increases.
Moreover, even when a spherical phosphor is used for the first phosphor layer 31, the effect becomes more remarkable if a plate-like phosphor is used for the second phosphor layer 32. I understand that. On the other hand, even if the visible light transmittance of the first phosphor layer 31 is the same, the first phosphor layer 31 is further enhanced by further increasing the visible light reflectance on the back plate side.
This means that the panel can be improved in luminance by increasing the amount of visible light transmitted through the panel.

[Other Items] Needless to say, the present invention is not limited to the above-described embodiment, and the following modifications and effects can be considered without departing from the gist of the invention.

(1) For example, it is also possible to form the first and second phosphor layers as described above only for the blue phosphor, and to otherwise use only the second phosphor layer as in the conventional case. In addition, the luminous efficiency can be increased to some extent as compared with the related art. This is because, in the conventional PDP, the blue phosphor usually has the lowest luminance, so that the amount of the red and green phosphor layers to be applied is reduced, or an additive such as silica is added to the phosphor. Since the luminance of the body layer was set low and a white balance was taken, the panel luminance had to be limited by the luminance of the blue phosphor, but the improvement of the luminance of the blue phosphor was realized. This is because the constraint is released.

(2) In the above embodiment, the AC type P
Although the DP has been described as an example, the present invention is not limited to this, and a DC-type PDP can be similarly implemented.

[0104]

As described above, according to the present invention, the phosphor layer is disposed over the surface of the back plate, the wall surface of the partition wall, and the surface of the front cover plate. Since the porosity (filling rate) of the phosphor layer in the front cover plate is larger (smaller) than the porosity (filling rate) of the phosphor layer in the back plate and the partition walls, the average particle size is A, and the weight ratio is 10 %.
When the maximum particle size in the range of% to 90% is dmax, the minimum particle size is dmin, and x expressed by x = 100 · A / (A + dmax−dmin) is defined as the particle size concentration (%). Since the particle size concentration of the phosphor particles used for forming the phosphor layer in the front cover plate is larger than the particle size concentration of the phosphor particles used for forming the phosphor layer in the back plate and the partition wall, Is a distance from the center point of the phosphor particles to the farthest point on the particle surface, c is a distance from the closest point to the closest point, and c / a is defined as the sphericity of the particles. Since the sphericity of the phosphor particles used to form the phosphor layer is greater than the sphericity of the phosphor particles used to form the phosphor layer in the back plate, the luminous efficiency is increased compared to the conventional case, and a fine cell structure is used. Also high It can be operated at light efficiency.

Here, the particle size concentration x of the phosphor particles used to form the phosphor layer on the front cover plate
Is desirably 50% or more.

It is more desirable that the particle diameter concentration x of the phosphor particles used for forming the phosphor layer on the front cover plate be 80% or more.

Further, it is desirable that the particle diameter concentration x of the phosphor particles used for forming the phosphor layer on the partition wall and the back plate is less than 50%.

It is more desirable that the phosphor layer is not formed in a region corresponding to the first electrode.

In addition, the sealing pressure of the gas medium is set to 760 to 760.
It is more desirable to set it to 4000 Torr.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an AC surface discharge type PDP according to an embodiment.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a sectional view taken along line YY of FIG. 1;

FIG. 4 is a conceptual diagram of an ink filling device used for forming a phosphor layer.

5A and 5B show an example of a state in which the phosphor ink filled in the recess between the partition walls 30 dries, where FIG. 5A shows a state immediately after the phosphor ink is applied, FIG. This shows the state after drying.

FIG. 6 is a schematic diagram two-dimensionally showing an arrangement state of particles when a phosphor layer is formed by using phosphor particle groups having different particle diameter concentration degrees x (%); Particle size concentration x
When a particle group having a large (%) is used (first phosphor layer 3
1) and (b) show the arrangement of particles when a particle group having a small particle concentration (%) is used (second phosphor layer 32).

FIG. 7 is a schematic diagram two-dimensionally illustrating an arrangement state of particles when a phosphor layer is formed using phosphor particle groups having different sphericities, and (a) is a particle group having a large sphericity. (First phosphor layer 31) and (b) show the arrangement of particles when a particle group having a small sphericity is used (second phosphor layer 32).

FIG. 8 is a characteristic diagram showing a relationship between a particle concentration degree (%) of a phosphor used for a first phosphor layer and panel luminance.

FIG. 9 is a schematic cross-sectional view showing an example of a conventional alternating current (AC) PDP.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Front panel (front cover plate) 11 Front glass substrate 12 Display electrode 13 Dielectric glass layer 14 Protective layer 14a Notch 20 Back panel (back plate) 21 Back glass substrate 22 Address electrode 23 Visible light reflective layer 30 Partition 31 First Phosphor layer 32 second phosphor layer 32a back surface 32b side surface 40 cell space 50 ink filling device 51 header 52 nozzle 61 front glass substrate 62 display electrode 63 dielectric glass layer 64 dielectric protection layer 65 rear glass substrate 66 Address electrode 67 Partition wall 68 Phosphor 68B Blue phosphor layer 68R Red phosphor layer 68G Green phosphor layer 69 Discharge space

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-138559 (JP, A) JP-A-5-121002 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 11/00-11/04 H01J 17/00-17/06 H01J 17/49

Claims (13)

(57) [Claims] 1. A state in which a front cover plate having a first electrode provided on a surface thereof and a back plate having a second electrode provided on a surface thereof face the first and second electrodes. The gap between the two plates is separated by a partition wall, and a gas that can be discharged to the remaining space is provided with a phosphor layer in the space partitioned by the partition wall. In the plasma display panel in which a medium is sealed, the phosphor layer is disposed over the surface of the back plate, the wall surface of the partition wall, and the surface of the front cover plate, and the phosphor in the front cover plate is provided. A plasma display panel, wherein the porosity of the layer is larger than the porosity of the phosphor layer in the back plate and the partition. 2. A state in which a front cover plate having a first electrode disposed on a surface thereof and a back plate having a second electrode disposed on a surface thereof face the first and second electrodes. The gap between the two plates is separated by a partition wall, and a gas that can be discharged to the remaining space is provided with a phosphor layer in the space partitioned by the partition wall. In the plasma display panel in which a medium is sealed, the phosphor layer is disposed over the surface of the back plate, the wall surface of the partition wall, and the surface of the front cover plate, and the phosphor in the front cover plate is provided. A plasma display panel, wherein the filling rate of the layer is smaller than the filling rate of the phosphor layer in the back plate and the partition. 3. A state in which a front cover plate having a first electrode disposed on a surface thereof and a back plate having a second electrode disposed on a surface thereof face the first and second electrodes. The gap between the two plates is separated by a partition wall, and a gas that can be discharged to the remaining space is provided with a phosphor layer in the space partitioned by the partition wall. In a plasma display panel in which a medium is sealed, the phosphor layer is disposed over the surface of the back plate, the wall surface of the partition wall, and the surface of the front cover plate, and has an average particle size of A, Weight ratio 10
When the maximum particle size in the range of% to 90% is dmax, the minimum particle size is dmin, and x expressed by x = 100 · A / (A + dmax−dmin) is defined as the particle size concentration (%). In the phosphor layer in the front cover plate, the degree of concentration of the phosphor particles used to form the phosphor layer is larger than the degree of concentration of the phosphor particles used to form the phosphor layer in the back plate and the partition. A plasma display panel characterized by the above-mentioned. 4. The particle concentration degree x of the phosphor particles used for forming a phosphor layer on the front cover plate is 5
4. The plasma display panel according to claim 3, wherein the ratio is 0% or more. 5. The concentration x of the particle diameter of the phosphor particles used for forming the phosphor layer on the front cover plate is 8
4. The plasma display panel according to claim 3, wherein the ratio is 0% or more. 6. The particle size concentration x of the phosphor particles used for forming the phosphor layer on the back plate and the partition wall.
The plasma display panel according to claim 3, wherein is less than 50%. 7. A state in which a front cover plate having a first electrode disposed on a surface thereof and a back plate having a second electrode disposed on a surface thereof face the first and second electrodes. The gap between the two plates is separated by a partition wall, and a gas that can be discharged to the remaining space is provided with a phosphor layer in the space partitioned by the partition wall. In a plasma display panel in which a medium is sealed, the phosphor layer is disposed over a surface of the back plate, a wall surface of the partition wall, and a surface of the front cover plate, and a center of the phosphor particles. When the distance from a point to the farthest point on the particle surface is a, the distance from the closest point to c is c, and c / a is defined as the sphericity of the particle, the phosphor layer in the front cover plate has
A plasma display panel, wherein the sphericity of the phosphor particles used to form the phosphor particles is larger than the sphericity of the phosphor particles used to form the phosphor layer on the back plate and the partition. 8. The plasma display panel according to claim 1, wherein the phosphor layer in the front cover plate is formed except for a region corresponding to the first electrode. 9. A first phosphor layer for forming a first phosphor layer on a surface of a front cover plate having electrodes disposed on the surface.
Step and, in the concave portion of the back plate where a partition is formed on the surface and a concave portion is formed between the partition walls,
A second step of forming a second phosphor layer, disposing a front cover plate and a back plate in parallel with the first phosphor layer and the second phosphor layer facing each other; A third step of enclosing a dischargeable gas medium in the recesses, wherein the average particle diameter is A, the maximum particle diameter in the range of 10% to 90% by weight is dmax, X = 100 · A with the minimum particle size as dmin
When x represented by / (A + dmax-dmin) is defined as the particle concentration (%), the formation of the first phosphor layer in the first step includes the formation of the second phosphor layer in the second step. A method for manufacturing a plasma display panel, characterized in that a phosphor having a particle diameter concentration larger than that of a phosphor used for forming a phosphor is used. 10. A first step of forming a first phosphor layer on the front surface of a front cover plate having electrodes disposed on the surface, forming a partition on the surface and forming a recess between the partitions. A second step of forming a second phosphor layer in the concave portion of the back plate, and a front cover plate and a back plate with the first phosphor layer and the second phosphor layer facing each other. A third step of arranging the dischargeable gas medium in the recesses in parallel with each other in the recessed state, from the center point of the phosphor particles to the farthest point on the particle surface. Is defined as a, the distance to the nearest point is defined as c, and c / a is defined as the sphericity of the particles.
The method of manufacturing a plasma display panel according to claim 1, wherein said phosphor layer is formed using a phosphor having a sphericity larger than that of said phosphor used for forming said second phosphor layer in said second step. 11. The method of manufacturing a plasma display panel according to claim 9, wherein said phosphor layer having a particle diameter concentration x of 50% or more is used for forming a phosphor layer on said front cover plate. 12. The method of manufacturing a plasma display panel according to claim 9, wherein said phosphor layer having a particle size concentration x of 80% or more is used for forming a phosphor layer on said front cover plate. 13. The method for manufacturing a plasma display panel according to claim 9, wherein said phosphor layer having a particle size concentration x of less than 50% is used for forming said phosphor layer on said back plate and said partition wall. .