U.S. patent number RE40,502 [Application Number 11/113,337] was granted by the patent office on 2008-09-16 for plasma display panel and method for manufacturing the same.
This patent grant is currently assigned to Fujitsu Hitachi Plasma Display Limited. Invention is credited to Akihiro Fujimoto, Shinji Kanagu, Yoshimi Kawanami, Yasuhiko Kunii, Toshiyuki Nanto, Masayuki Shibata, Yasuhiro Wakabayashi, Yusuke Yajima, Kenichi Yamamoto, Atsushi Yokoyama.
United States Patent |
RE40,502 |
Kunii , et al. |
September 16, 2008 |
**Please see images for:
( Certificate of Correction ) ** |
Plasma display panel and method for manufacturing the same
Abstract
.[.A plasma display panel has a good productivity of partition
formation and air exhaustion process and realizes a bright and
stable display. A discharge gas is filled in a gap between two
substrates. A mesh-patterned partition is arranged on the inner
surface of one of the substrates for dividing the gap into plural
squares corresponding to a cell arrangement. The partition has low
portions forming a mesh-like air path that travels through all of
the gas-filled space enclosed by the partition, in a plan view..].
.Iadd.A plasma display panel includes two spaced substrates
defining a gap therebetween. The gap is divided by intersecting
walls into columns and rows of discharge cells. Portions of a wall
that are lower in height than remaining portions of the wall define
a flow path. The plasma display panel realizes a bright and stable
display. .Iaddend.
Inventors: |
Kunii; Yasuhiko (Miyazaki,
JP), Shibata; Masayuki (Miyazaki, JP),
Kawanami; Yoshimi (Miyazaki, JP), Yamamoto;
Kenichi (Miyazaki, JP), Yokoyama; Atsushi
(Miyazaki, JP), Yajima; Yusuke (Miyazaki,
JP), Kanagu; Shinji (Miyazaki, JP),
Wakabayashi; Yasuhiro (Miyazaki, JP), Fujimoto;
Akihiro (Miyazaki, JP), Nanto; Toshiyuki
(Miyazaki, JP) |
Assignee: |
Fujitsu Hitachi Plasma Display
Limited (Kawasaki, JP)
|
Family
ID: |
18756147 |
Appl.
No.: |
11/113,337 |
Filed: |
April 25, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
09778879 |
Feb 8, 2001 |
06608441 |
Aug 19, 2003 |
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Foreign Application Priority Data
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Sep 6, 2000 [JP] |
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2000-269569 |
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Current U.S.
Class: |
313/584; 313/586;
313/585 |
Current CPC
Class: |
H01J
9/242 (20130101); H01J 11/36 (20130101); H01J
11/12 (20130101); H01J 2211/361 (20130101) |
Current International
Class: |
H01J
17/49 (20060101) |
Field of
Search: |
;313/584,582,493,586,587,585 ;445/25,46 ;345/60 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 920 048 |
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Jun 1999 |
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EP |
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4-206126 |
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Jul 1992 |
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JP |
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4-274141 |
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Sep 1992 |
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JP |
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4-277439 |
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Oct 1992 |
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JP |
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5-094772 |
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Apr 1993 |
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JP |
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9-115452 |
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May 1997 |
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JP |
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9-190768 |
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Jul 1997 |
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JP |
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11-213896 |
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Aug 1999 |
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JP |
|
11-297211 |
|
Oct 1999 |
|
JP |
|
Other References
Korean Intellectual Property Official Communication dated Oct. 25,
2006. cited by other .
European Search Report, dated Sep. 8, 2004, and issued in
corresponding European Patent Application No. 01301155.6-2208, (3
pages). cited by other.
|
Primary Examiner: Truong; Bao Q
Attorney, Agent or Firm: Staas & Halsey LLP
Claims
What is claimed is:
1. A plasma display panel having a display surface, comprising: a
pair of spaced substrates defining a gap therebetween; a discharge
gas filled in the gap between the substrates; and a mesh-patterned
partition, disposed between respective inner surfaces of the
substrates and extending over all of the display surface, dividing
the gap into a cell arrangement of plural gas-filled cells, each
cell having a surrounding partition sidewall, portions of the
respective surrounding sidewall of the plural gas-filled cells
.[.forming.]. .Iadd.are lowered to form .Iaddend.mesh-like air
paths extending through all of the plural gas-filled cells and to a
periphery of the partition.
2. The plasma display panel according to claim 1, wherein
.[.portions of the partition sidewalls are lowered to form the
mesh-like air paths,.]. a difference between respective heights of
the lowered portions and the other portions upper surface of the
partition sidewalls is more than 5% of a maximum height of the
partition.
3. The plasma display panel according to claim 1, wherein spaced,
opposed portions of the respective sidewalls of the plural cells,
aligned in row and column directions, are of a reduced height,
relative to other portions of the respective sidewalls of the
plural cells, thereby forming corresponding air paths.
4. The plasma display panel according to claim 1, wherein a
fluorescent material is arranged on a row direction side and a
column direction side of the respective partition sidewall of each
of the cells.
5. The plasma display panel according to claim 1, wherein the cells
in the row direction and in the column direction form a matrix
display and an inter-row portion of the partition, that forms a
boundary wall between adjacent rows, is of a lower height than
other portions of the partition.
6. The plasma display panel according to claim 5, wherein the
inter-row portion defines at least one space for each column.
7. The plasma display panel according to claim 6, wherein the
inter-row portion has a ladder pattern.
8. The plasma display panel according to claim 5, wherein the
partition is arranged on a back substrate, an electrode including a
transparent conductive film and a metal film extending over all
columns is arranged on the front substrate, and the metal film and
the inter-row portion are overlaid.
9. The plasma display panel according to claim 1, wherein the
partition is formed of a baked material having a heat shrink
property, and a width of the reduced height portions of the
partition sidewalls is greater than a width of the other portions
of the sidewalls of the partition.
10. A method for manufacturing a plasma display having a display
screen .[.accordingly claim 1.]. .Iadd.having a pair of spaced
substrates defining a gap therebetween, a discharge gas filled in
the gap between the substrates, and a mesh-patterned partition,
disposed between respective inner surfaces of the substrates and
extending over all of the display surface, dividing the gap into a
cell arrangement of plural gas-filled cells, each cell having a
surrounding partition sidewall, portions of the respective
surrounding sidewall of the plural gas-filled cells are lowered to
form mesh-like air paths extending through all of the plural
gas-filled cells and to a periphery of the partition.Iaddend.,
.Iadd.said method .Iaddend.comprising: forming a layer of a
material having a heat shrink property on a substrate; patterning
the layer to define the mesh-patterned partition extending over all
of the display screen and defining a cell arrangement of plural
cells, each cell having a partition sidewall, portions of the
respective surrounding sidewalls of the plural cells forming
mesh-like air paths extending through all of the plural cells and
to a periphery of the mesh-patterned partition; and forming the
partition by baking the patterned layer.
11. The method according to claim 10, wherein the patterning
further comprises placing a cutting mask corresponding to the cell
arrangement on the layer, and cutting non-masked portions of the
layer by sandblasting.
12. The plasma display panel according to claim 3, wherein portions
of the partition sidewalls are lowered to form the mesh-like air
paths, a difference between respective heights of the lowered
portions and an upper surface of the partition sidewall being more
than 10 .mu.m.
13. The plasma display panel according to claim 3, wherein the air
paths extend continuously over a complete length of each of the row
and column directions.
14. A plasma display panel having a display surface, comprising: a
pair of substrates having parallel, spaced and opposed respective
inner surfaces defining a gap therebetween; a discharge gas filled
in the gap between the substrates; and a mesh-patterned partition
disposed between the respective inner surfaces of the substrates
and dividing the gap into a cell arrangement of plural gas-filled
cells in plural, transverse rows and columns covering the display
surface and in which the partition defines a surrounding sidewall
for each cell, .[.spaced and opposed.]. .Iadd.at least
.Iaddend.portions of the respective sidewalls of the plural cells,
aligned in both the row and column directions, .[.defining.].
.Iadd.are lowered in height to define .Iaddend.corresponding air
paths in the row and column directions, that travel through all of
the gas-filled cells to a periphery of the partition.
.Iadd.15. A plasma display panel, comprising: a pair of spaced
substrates defining a gap therebetween; a plurality of first walls
dividing the gap into plural columns, each column comprising plural
cells; a plurality of second walls intersecting said first walls
and dividing the gap into plural rows, each row comprising plural
cells; and at least portions of said first walls, in the
intersections with said second walls, being of a lower height than
a height of remaining portions of the first walls and defining flow
paths extending through adjacent cells. .Iaddend.
.Iadd.16. The plasma display panel recited in claim 15, wherein
said flow path is defined by respective intersecting portions of
the first and second walls, of lesser height than a height of
remaining portions of the first wall. .Iaddend.
.Iadd.17. The plasma display panel recited in claim 15, wherein at
least one of said first and second walls has a zigzag pattern
comprising a non-linear wall surrounding each associated cell.
.Iaddend.
.Iadd.18. A plasma display panel, comprising: a pair of spaced
substrates defining a gap therebetween; a plurality of first walls
dividing the gap into plural columns, each column comprising plural
cells; a plurality of second walls intersecting said first walls
and dividing the gap into plural rows, each row comprising plural
cells; and the second walls having a width greater than 130% of a
width of the first walls, at least portions of the intersections of
the first and second walls being of a lower height than a height of
remaining portions of the first walls and defining flow paths
extending through adjacent cells. .Iaddend.
.Iadd.19. The plasma display panel recited in claim 18, wherein
said flow path is defined by respective intersecting portions of
the first and second walls, of lesser height than a height of
remaining portions of the first wall. .Iaddend.
.Iadd.20. The plasma display panel recited in claim 18, wherein at
least one of said first and second walls has a zigzag pattern
comprising a non-linear wall surrounding each associated cell.
.Iaddend.
.Iadd.21. A plasma display panel, comprising: a pair of spaced
substrates defining a gap therebetween; a discharge gas in the gap
between the substrates; a plurality of first walls dividing the gap
into plural columns, each column comprising plural gas filled
cells; a plurality of second walls intersecting with said first
walls and dividing the gap into plural rows, each row comprising
plural gas filled cells; and at least portions of said first walls,
in the intersections with said second walls being of a lower height
than a height of remaining portions of the first walls and defining
flow paths extending through adjacent cells. .Iaddend.
.Iadd.22. The plasma display panel recited in claim 21, wherein
said flow path is defined by respective intersecting portions of
the first and second walls, of lesser height than a height of
remaining portions of the first wall. .Iaddend.
.Iadd.23. The plasma display panel recited in claims 21, wherein at
least one of said first and second walls has a zigzag pattern
comprising a non-linear wall surrounding each associated gas filled
cell. .Iaddend.
.Iadd.24. A plasma display panel, comprising: a pair of spaced
substrates defining a gap therebetween; a discharge gas filled in
the gap between the substrates; a plurality of first walls dividing
the gap into plural columns, each column comprising of plural gas
filled cells; a plurality of second walls intersecting said first
walls and dividing the gap into plural rows, each row comprising
plural gas filled cells; and the second walls having a width
greater than 130% of a width of the first walls, at least portions
of the intersections of the first and second walls being of a lower
height than a height of remaining portions of the first walls and
defining flow paths extending through adjacent gas filled cells.
.Iaddend.
.Iadd.25. The plasma display panel recited in claim 24, wherein
said flow path is defined by respective intersecting portions of
the first and second walls, of lesser height than a height of
remaining portions of the first wall. .Iaddend.
.Iadd.26. The plasma display panel recited in claims 24, wherein at
least one of said first and second walls has a zigzag pattern
comprising a non-linear wall surrounding each associated gas filled
cell. .Iaddend.
.Iadd.27. A plasma display panel having a display surface,
comprising: a pair of spaced substrates defining a gap
therebetween; a discharge gas filled in the gap between the
substrates; and a partition disposed between respective inner
surfaces of the substrates and extending over all of the display
surface, said partition comprising a plurality of first walls
dividing the gap into rows of plural gas filled cells and a
plurality of second walls intersecting with said first walls,
dividing the gap into columns of plural gas filled cells, wherein a
portion of said first wall including at least a part of each
intersection of said first and second walls is of a lower height
than a portion of the second wall, thereby forming air paths
extending through the adjacent gas filled cells and to a periphery
of the partition. .Iaddend.
.Iadd.28. A plasma display panel having a display surface,
comprising: a pair of spaced substrates defining a gap
therebetween; a discharge gas filled in the gap between the
substrates; a partition comprising a plurality of vertical walls
and a plurality of horizontal walls, disposed between respective
inner surfaces of the substrates and extending over all of the
display surface, dividing the gap into a matrix arrangement of
plural rows and columns of plural gas filled cells, said horizontal
wall having a width more than 130% larger than a width of the
vertical wall; air paths extending between adjacent gas filled
cells, through upper surface will portions of at least respective
intersections of the vertical and horizontal walls, and to a
periphery of the partition. .Iaddend.
.Iadd.29. The plasma display panel recited in claim 28, wherein
said air paths are provided in a pattern through reduced height
upper surface wall portions on the horizontal walls, in crossing
parts of the respective vertical and horizontal walls.
.Iaddend.
.Iadd.30. The plasma display panel recited in claim 28, wherein at
least one of said vertical and horizontal walls has a zigzag
pattern, surrounding each gas filled cell with a non linear
sidewall. .Iaddend.
.Iadd.31. The plasma display panel recited in claim 29, wherein at
least one of said vertical and horizontal walls has a zigzag
pattern, surrounding each gas filled cell with a non linear
sidewall. .Iaddend.
.Iadd.32. The plasma display panel recited in claim 28, wherein
each of said horizontal walls includes at least one space at a
portion corresponding to every column of the matrix arrangement of
plural gas filled cells. .Iaddend.
.Iadd.33. A plasma display panel, comprising: a pair of front
substrate and rear substrate having parallel, spaced and opposed
respective inner surfaces defining a gas filled gap therebetween; a
plurality of display electrode pairs arranged on the inner surface
of the front substrate in parallel relationship and extending in a
horizontal direction; a plurality of address electrodes arranged on
the inner surface of the rear substrate in parallel relationship
and extending in a vertical direction; a mesh patterned partition
disposed between the respective inner surfaces of the front and
rear substrates and dividing the gas filled gap into a cell
arrangement of plural discharge cells in plural, transverse rows
and columns, said mesh patterned partition including a plurality of
inter row portions, each thereof extending in a horizontal
direction between respective, adjacent vertical walls defining
corresponding rows of the discharge cell arrangement, each of said
inter row portions comprises at least two horizontal walls, a width
of each inter row portion being larger than a width of each
vertical wall of said mesh patterned partition; and an air paths
extending between the adjacent discharge cells through
corresponding portions above an upper surface of each of the
horizontal walls of the inter row portions reduced in height by
heat shrinking. .Iaddend.
.Iadd.34. A plasma display panel recited in claim 33, wherein said
air path is defined as a pattern of reduced height upper surface
wall portions in respective crossing parts of the mesh patterned
partition. .Iaddend.
.Iadd.35. A plasma display panel recited in claim 33, wherein each
said display electrode comprises a transparent conductive film and
a metal film extending over all columns and arranged on the front
substrate, the metal film and the inter row portion being overlaid.
.Iaddend.
.Iadd.36. A plasma display panel recited in claim 34, wherein each
said display electrode comprises a transparent conductive film and
a metal firm extending over all columns and is arranged on the
front substrate, the metal film and the inter row portion being
overlaid. .Iaddend.
.Iadd.37. A method for manufacturing a plasma display panel having
a display screen and a mesh patterned partition between a pair of
opposed substrates, comprising: forming a layer of material having
a heat shrink property on one substrate; patterning the layer to
define the mesh patterned partition extending over all of the
display screen and defining a matrix arrangement of plural cells in
plural, transverse row and column directions, each cell surrounded
with partition sidewalls, each of opposing sidewalls in a column
direction having a width larger than the opposing sidewalls in a
row direction; and baking the patterned layer, thereby forming the
partition so as to have a reduced height portion in each respective
part of said opposing sidewall, extending in a row direction, of a
larger width. .Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma display panel (PDP)
having a mesh-patterned partition, each square of which encloses
one or more cells for constituting a display surface and a method
for manufacturing the PDP.
A PDP is commercialized for a wall-hung TV set, whose screen size
has reached 60 inches. PDP is a digital display device comprising
binary light emission cells, so it is suitable for a display of
digital data and is expected as a multimedia monitor. In order to
increase applications of a PDP, a new panel structure is under
development, which can provide a brighter and more stable display
and can be manufactured in a high productivity.
2. Description of the Prior Art
An AC type PDP for a color display employs a surface discharge
format. The surface discharge format has an arrangement of
electrodes in which display electrodes that become anodes and
cathodes in a display discharge for ensuring a luminance are
arranged in parallel on a front or back substrate, and address
electrodes are arranged so as to cross a pair of the display
electrodes. In the surface discharge format PDP, a partition is
necessary for separating a discharge for each column of a matrix
display along the longitudinal direction of the display electrode
(hereinafter referred to as the row direction). The partition also
works as a spacer for defining a discharge space size in the
direction of the panel thickness.
A partition pattern (a shape of the partition in the plan view) is
broadly divided into a stripe pattern and a mesh pattern. The
stripe pattern divides the discharge space for cells arranged in
the row direction (i.e., in each column). In the stripe pattern,
the discharge space of cell included in each column is not
separated, so that exhausting of inner air and filling of discharge
gas are relatively easy in a manufacturing process of a PDP. The
mesh pattern divides the discharge space both in the row direction
and in the column direction. A typical mesh pattern is a check
pattern. A mesh pattern has an advantage in that the discharge is
separated for each cell and that a fluorescent material is arranged
on a side face of the partition so as to enclose the cell for
increasing a light emission area. The mesh pattern, however, has a
disadvantage in that a gap generated by subtle unevenness on the
upper surface of the partition becomes an air path in the inner air
exhaustion, so a resistance of the air exhaustion is large and it
takes a long time for the process.
Conventionally, a partition structure of an overlaying form of the
mesh-patterned partition and the stripe-patterned partition (this
is called a composite pattern structure) is known. In this
structure, since the discharge space is continuous as in the case
of the stripe pattern, the air exhaustion resistance is smaller
than in the case where the stripe-patterned partition is not
overlaid. Furthermore, an improved composite pattern structure is
disclosed in Japanese unexamined patent publication No. 4-274141,
in which a stripe-patterned partition is provided with a hiatus for
each cell, so that a grid-shaped air path (air exhaustion path) is
formed for the gas to flow not only in the column direction but
also in the row direction.
The above-explained partition having the composite pattern
structure has a mesh-patterned partition whose banding portion in
the column direction or the row direction is raised. There was a
problem that the partition forming process becomes complicated for
forming the above-mentioned structure on the inner surface of one
of the substrate pair. Furthermore, if a mesh-patterned partition
is disposed at one of the substrates and if a stripe-patterned
partition is disposed on the other partition, the fluorescent
material should be arranged on both of the substrates for
increasing the area in which the fluorescent material is formed. In
addition, a registration of the substrate pair in the assembling
process is difficult. Thus, the partition having the composite
pattern structure is adverse from the viewpoint of the
productivity.
There is a method of forming the air path by cutting a part of the
partition. However, this method may increase the number of
manufacturing steps for the cutting process and may reduce the
manufacturing yield since the partition can be broken by the
cutting process.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a PDP that has a
good productivity of partition formation and air exhaustion process
and can display more brightly and more stably than a PDP that has a
stripe-patterned partition.
According to the present invention, a mesh-patterned partition is
arranged on the inner surface of one of the substrates. The
partition has low portions that form a mesh-like air path that
travels through all of the gas-filled space enclosed by the
partition in a plan view. For example, in a simple check pattern in
which a line along the horizontal direction and a line along the
vertical direction cross each other, the portion corresponding to
the line along the horizontal direction is made low. In this case,
the pattern width (the line width) of the portion corresponding to
the line along the horizontal direction is made thicker than the
pattern width of the portion corresponding to the line along the
vertical direction so as to generate a height difference. The
shrink quantity in the thick portion is smaller in the width
direction but is larger in the height direction than the thin
portion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing a cell structure of a PDP according to
the present invention.
FIG. 2 is a plan view showing the arrangement relationship between
the display electrode and the partition.
FIG. 3 is a plan view showing a partition pattern.
FIG. 4 is a diagram showing a solid structure of the partition.
FIG. 5 is a schematic diagram showing heat shrink in the partition
forming process.
FIG. 6 is a diagram showing a baking profile in the partition
forming process.
FIGS. 7, 8A and 8B show variations of the partition pattern.
FIGS. 9A-12 show variations of the display electrode pattern.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, the present invention will be explained in detail with
reference to embodiments and accompanied drawings.
FIG. 1 is a diagram showing a cell structure of a PDP according to
the present invention. FIG. 2 is a plan view showing the
arrangement relationship between the display electrode and the
partition. FIG. 1 is a drawing of an inner structure, which shows a
pair of substrate structures being separated from each other.
The PDP 1 comprises a pair of substrate structures (a structure
including a substrate on which cell elements are arranged) 10, 20,
and the display surface ES comprises m.times.n cells. In each cell,
the display electrodes X, Y constituting an electrode pair for
generating the display discharge are extending in the row direction
(the horizontal direction) of the matrix display, and the address
electrodes A are extending in the column direction (the vertical
direction).
The display electrodes X, Y are arranged on the inner surface of
the glass substrate 11 of the front substrate structure 10 as a
pair for each row. Herein, the "row" means a set of cells whose
positions in the column direction are the same, and the number of
the cells is equal to the number of columns (m). Each of the
display electrodes X and Y includes a transparent conductive film
41 that forms a surface discharge gap (a discharge slit) and a
metal film (a bus conductor) 42 that is overlaid on the edge in the
column direction. The display electrodes X, Y are covered with a
dielectric layer 17 having the thickness of approximately 20-40
.mu.m, and the surface of the dielectric layer 17 is coated with a
protection film 18 made of magnesia (MgO). The electrode gap
between rows (that is called a reverse slit) is provided with a
dark color layer 65 that is called a black stripe by applying a
paint on the outer surface of the glass substrate 11 or by forming
a colored glass layer including fillers such as manganese, iron
oxide, chromium and other colorant so as to increase contrast (see
FIG. 2).
The address electrodes A are arranged on the inner surface of the
glass substrate 21 of the back substrate structure 20 as one for
each column and are covered with a dielectric layer 24. On the
dielectric layer 24, the partition 29 is disposed, which has a grid
pattern with partially low profile structure that is unique to the
present invention. The partition 29 is made of a baked material of
a low melting point glass and includes a portion for dividing the
discharge space into columns (hereinafter referred to as a vertical
wall) 291 and a portion for dividing a discharge space into rows
(hereinafter referred to as a horizontal wall) 292. The
intersection of the vertical wall 291 and the horizontal wall 292
is a common part of them. The horizontal wall 292 is lower in
height (i.e., is shorter) than the vertical wall 291 by
approximately 10 .mu.m. The upper surface of the dielectric layer
24 and the side face (i.e., side walls) of the partition 29 are
covered with red, green and blue colors of fluorescent material
layers 28R, 28G and 28B for color display. The italic letters (R, G
and B) in FIG. 1 signify light emission colors of the fluorescent
materials. The color arrangement has a repeating pattern of red,
green and blue colors in such a way that the cells in a column have
the same color. The fluorescent material layers 28R, 28G and 28B
are excited by ultraviolet rays generated by the discharge gas in
the corresponding cell and emit light.
As shown in FIG. 2, the metal film 42 of each of the display
electrodes X, Y is overlaid on the partition 29 so as to cover the
partition 29 partially, for reducing reflection of external light
rays, and to avoid overlapping onto the fluorescent material on the
partition sidewalls. The transparent conductive film 41 is
patterned in such a way that the portion for the surface discharge
is substantially separated from the portion overlaid on the metal
film 42, for suppressing discharge current so as to enhance the
efficiency of light emission. In the case of 42 inch wide VGA type,
the portion for the display discharge of the transparent conductive
film 41 is separated from the horizontal wall 292 by a distance
more than 30 .mu.m, so that energy loss is largely reduced compared
with the case where the distance is less than 30 .mu.m. It is
desirable that the distance between the horizontal wall 292 and the
transparent conductive film 41 is set so that the discharge current
is reduced by more than 5%.
The PDP 1 having the above-mentioned structure can be manufactured
by the following process. (1) Providing the glass substrates 11, 21
with a predetermined element separately to make the substrate
structures 10, 20. (2) Overlaying the substrate structures 10, 20,
and sealing the rim of the opposing area. (3) Exhausting the inner
air and filling the discharge gas through an air hole that is
formed in the back substrate structure 20. (4) Closing the air
hole.
FIG. 3 is a plan view showing a partition pattern. FIG. 4 is a
diagram showing a solid structure of the partition.
As shown in FIG. 3, the partition pattern is a grid pattern in
which each square of the grid pattern encloses a cell C
individually. However, it is not a simple check pattern. Namely,
the inter-row portion 293 (the portion between the cells aligned in
the column direction) of the partition 29 includes two horizontal
walls 292 and a part of the vertical wall 291. The plan view
pattern of the inter-row portion 293 is made of a ladder pattern,
and a space 33 is formed between the gas-filled space 32 that
corresponds to each of the cells C aligned in the column direction.
Since the dielectric constant of the discharge gas is approximately
one eighth of that of a low melting point glass that is a common
material of the partition, capacitance between the display
electrodes of the neighboring rows is reduced, so that a waste of
power consumption can be reduced and response of drive control can
be improved. In the check pattern, the side face of the vertical
wall 291 and the side face of the horizontal wall 292 respectively
are provided with a fluorescent material, so that the light
emission area is enlarged and the light emission efficiency can be
improved.
In the PDP 1 of this embodiment, the inter-row portion 293 of the
partition 29 is made approximately 10 .mu.m lower than other
portions, i.e., made approximately 7% lower, relative to the
maximum height (140 .mu.m) of the partition 29. Thereby, an air
exhaustion path 90 is formed which has a grid shape in the plan
view for enabling air exhaustion both in the column direction and
in the row direction. The width W20 of the inter-row portion 293 is
substantially large, and the inter-row portion 293 is substantially
lowered, relative to the other portions, and therefor, the air
exhaustion conductance is substantially the same as the stripe
pattern. Concrete dimension of the partition 29 is as follows. row
pitch P1: 1080 .mu.m column pitch P2: 360 .mu.m width W11 of the
upper surface of the vertical wall 291: approximately 70 .mu.m
width W12 of the bottom surface of the vertical wall 291:
approximately 140 .mu.m height H1 of the vertical wall 291:
approximately 140 .mu.m width W21 of the upper surface of the
horizontal wall 292: approximately 100 .mu.m width W22 of the
bottom surface of the horizontal wall 292: approximately 200 .mu.m
height H2 of the horizontal wall 292: approximately 130 .mu.m
column direction size D11 of the space 32: approximately 680 .mu.m
row direction size D22 of the space 32: approximately 290 .mu.m
column direction size D12 of the space 33: approximately 200 .mu.m
width W20 of the inter-row portion 293: approximately 400 .mu.m
It is important that the width W20 of the inter-row portion 293 is
substantially larger than the width W11 of the vertical wall 291,
so that the difference between the widths makes a height difference
between the inter-row portion 293 and other portions. Namely, in a
baking process of a material such as a general low melting point
glass having a heat shrink property, as shown schematically in FIG.
5, the shrink quantity in the height direction depends on the width
of the pattern. The shrink can be generated both in the width
direction and in the height direction as a whole in the portion 29A
having a small pattern width. In contrast, in the portion 29B
having a large pattern width, the shrink in the width direction is
suppressed more at the portion closer to the center in width
direction, so that the shrink is generated more in the height
direction, compensating for the suppression in the width direction.
Therefore, the thick portion 29B becomes lower in height than the
thin portion 29A. In addition, an isotropic shrink occurs in the
upper portion of the wall material layer since the shrink can
easily occur in any direction, while the shrink in the direction of
the substrate surface is suppressed in the bottom portion due to
the bond of the substrate. Therefore, the shrink quantity in the
height direction becomes larger than the shrink quantity in the
direction of the substrate surface. Namely, even if the width of
the upper surface is substantially uniform before baking, and if
the widths of the bottom surface are different, the height after
baking of the material layer having larger width of the bottom
surface becomes lower than the material layer having smaller width
of the bottom surface. Considering this fact, the pattern width of
the partition is defined as the dimension at the position whose
distance from the bottom surface is 10% of the height in this
specification. It is desirable that the pattern width of the thick
portion is set to be more than 130% of the pattern width of the
thin portion so that a difference of height is generated that is
sufficient for air exhaustion. In the case of the above-mentioned
partition size, two horizontal walls 292 and the portion between
them (a part of the vertical wall 291) are shrunk in the same way
in the height direction, and a partition 29 is obtained that has
two inter-row portions 293 having low profile as a whole in the
inter-row portion 293 of the ladder pattern.
The composition of the low melting point glass that is a material
of the partition 29 is shown in Table 1.
TABLE-US-00001 TABLE 1 Composition of the low melting point glass
Components Content (wt %) PbO 50-60 B.sub.2O.sub.3 5-10 SiO.sub.2
10-20 Al.sub.2O.sub.3 15-25 CaO -5
Concerning optical characteristics of the partition 29, it is
desirable that it is semitransparent having the absorptance of
visual light at approximately 80% per 30 .mu.m of film thickness.
If it is semitransparent, light rays generated at the vicinity of
the top of the partition pass the partition and contribute to
improvement of the luminance, while external rays that entered the
partition are reflected by the bottom surface of the partition and
are absorbed by the partition before reaching the front surface.
Therefore, a display having a good contrast can be realized.
The process of forming the partition 29 is as follows. (1) Forming
the partition material layer having the thickness of approximately
200 .mu.m made of a uniform paste mixture of a low melting point
glass powder having the components shown in Table 1 and a vehicle
so as to cover the dielectric layer 24. The partition material
layer may be formed by any method such as a screen printing method,
a laminating method in which a green sheet is transferred, or other
method. (2) Drying the partition material layer, and then sticking
thereto a photosensitive dry film (or a resist material is
applied), and forming a cut mask of the grid pattern corresponding
to the partition 29 by using photolithography, including exposure
and development. The mask pattern size is set larger that the
desired partition size considering the heat shrink quantity. (3)
Grinding the non-masking portion of the partition material layer by
a sandblaster until the dielectric layer 24 is exposed (the
partition material layer is patterned). (4) Performing a heating
process according to the baking profile shown in FIG. 6 to bake the
partition material layer so that the partition 29 is formed.
FIGS. 7, 8A and 8B show variations of the partition pattern.
The partition 29b shown in FIG. 7 includes a vertical wall 291 and
a horizontal wall 292b. The partition 29b corresponds to such that
the inter-row portion 293 of the partition 29 shown in FIG. 3 is
replaced with the horizontal wall 292b. The partition 29c shown in
FIG. 8A includes a vertical wall 291c and a horizontal wall 292c.
The pattern thereof in a plan view is a mesh pattern in which the
positions of cells of the neighboring rows are shifted by a half
pitch from each other. In the partition 29c, the pattern width of
the horizontal wall 292c is set larger than the pattern width of
the vertical wall 291c, so that the horizontal wall 292c is lower
than the vertical wall 291c, and a mesh-like air exhaustion path
90c is formed. The partition 29d shown in FIG. 8B includes a
vertical wall 291d and a horizontal wall 292d, and the pattern
thereof in a plan view is a honeycomb mesh pattern. In the
partition 29d, too, the pattern width of the zigzag banding
horizontal wall 292d is set larger than the pattern width of the
vertical wall 291d, so that the horizontal wall 292d is lower than
the vertical wall 291d, and a mesh-like air exhaustion path 90d is
formed. In a PDP having the partitions 29c and 29d, the address
electrodes A can be arranged so that the address electrode A weaves
in and out of the cells shifted from each other by a half pitch, or
that a linear address electrode A is arranged being overlaid on the
vertical walls 291c and 291d. The display electrodes X, Y can be
arranged so that a pair of display electrodes is arranged for each
row as shown in FIG. 2, or that three display electrodes are
arranged for two rows as a display electrode is shared by two
neighboring rows for display. In any way, the entire bus conductor
is overlaid on the horizontal walls 292c and 292d, so that shading
can be avoided.
FIGS. 9A-12 show variations of the display electrode pattern.
Each of the display electrodes Xb and Yb shown in FIG. 9A includes
a transparent conductive film 41b and a metal film 42b and
corresponds to such display electrodes wherein the pattern of the
transparent conductive film 41 of the display electrodes X, Y shown
in FIG. 2 is changed. In the display electrodes Xb and Yb, the
portion of the transparent conductive film 41 to be a discharge
surface is connected to the portion that is overlaid on the metal
film 42b at the position where it is not overlaid on the vertical
wall of the partition 29. Each of the display electrodes Xc and Yc
shown in FIG. 9B includes a transparent conductive film 41c and a
metal film 42c. The metal film 42c is arranged at the position
where it is not overlaid on the horizontal wall of the partition
29. In the display electrodes Xd and Yd shown in FIG. 10A, the
portion of the transparent conductive film 41d that forms the
surface discharge gap to be the discharge surface is divided into
columns to be a T-shape. The portion of the transparent conductive
film 41d that is overlaid on the metal film 42b is straddling over
plural columns. Each of the display electrodes Xe and Ye shown in
FIG. 10B includes a T-shaped transparent conductive film 41e that
is divided for each column and a metal film 42b for supplying
electricity to the transparent conductive film. The structures of
FIGS. 10A and 10B in which the transparent conductive film is
divided are effective for suppressing a discharge current and for
reducing a capacitance between electrodes.
In the example shown in FIG. 11 and in the example shown in FIG.
12, a bus conductor is provided for hiding the reverse slit, so
that the process of forming the black stripe can be omitted. In
FIGS. 11 and 12, the partition 29e includes a vertical wall 291 and
a horizontal wall 292e and corresponds to such partition wherein
the inter-row portion 293 of the partition 29 shown in FIG. 3 is
replaced with three horizontal walls 292e. However, the following
electrode structure can be applied both to the partition 29 shown
in FIG. 2 and to the partition 29b shown in FIG. 7.
In FIG. 11, each of the display electrodes Xf and Yf includes a
transparent conductive film 41f and a metal film 42d and is
arranged so that the neighboring electrodes of the neighboring rows
are the same kind (e.g., in the order of X, Y, Y, X, X, Y, . . . ).
The transparent conductive film 41f is patterned in the same way as
the transparent conductive film 41b shown in FIG. 9A except for the
size of the portion that is overlaid on the metal film 42d. The
display electrodes Xf and Yf have a feature in that the metal film
42d as a bus conductor has a large width over two neighboring
horizontal walls 292e. Since an element close to the display
surface is drawn at the upper in the figure, a part of the metal
film 42d is covered with the transparent conductive film 41f.
However, actually in the observation from the display surface side,
the metal film 42d can be seen through the transparent conductive
film 41f. Namely, the entire metal film 42d works as a shading
member for hiding the structure thereunder. Therefore, it is not
necessary to provide another shading member (a black stripe) to the
inter-row portion (the reverse slit), so that the manufacturing
steps of a PDP can be reduced. In addition, since the width of the
metal film 42d is enlarged, a line resistance of each of the
display electrodes Xf and Yf decreases. Thus, the generation of
Joule heat can be reduced, and the voltage drop is also reduced
when the discharge current flows.
In FIG. 12, each of the display electrodes Xg and Yg includes a
transparent conductive film 41g and a metal film 42e and three
display electrodes are arranged for two rows so that a display
electrode is shared by two neighboring rows for display (in the
order of X, Y, X, Y, . . . ). The metal film 42e of the display
electrodes Xg and Yg have a large width over three neighboring
horizontal walls 292e. The example of FIG. 12 has the same
advantage as the example of FIG. 11 in that the manufacturing steps
can be reduced, and that the line resistance can be reduced.
In the above-mentioned embodiment, the dimension and the material
of the partition 29 are not limited to the examples. The plan-view
pattern of the partitions 29, 29b-29e is not limited to that
enclosing a cell. It can be a mesh pattern enclosing plural cells
as a unit.
According to the present invention, a PDP that has a good
productivity of partition formation and air exhaustion process and
can display more brightly and more stably than a PDP that has a
stripe-patterned partition can be realized.
While the presently preferred embodiments of the present invention
have been shown and described, it will be understood that the
present invention is not limited thereto, and that various changes
and modifications may be made by those skilled in the art without
departing from the scope of the invention as set forth in the
appended claims.
* * * * *