Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
2001-05-14
2004-10-05
Ramsey, Kenneth J. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
C445S024000, C313S582000, C313S587000
Reexamination Certificate
active
06800010
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for manufacturing a display panel constructed from a pair of connected substrates, and in particular to a method for applying a bonding agent to the substrates.
BACKGROUND ART
An AC-type plasma display panel (hereafter abbreviated to PDP) is a type of gas discharge panel, well-known in the art as one example of a display panel.
A PDP is illustrated in FIG.
42
. Here, the PDP is constructed from a front substrate
2000
and a back substrate
2100
. The front substrate
2000
is generally produced by forming discharge electrodes
2002
upon a front glass plate
2101
. This structure is then covered with a dielectric glass layer
2003
and a protective layer of magnesium oxide (MgO)
2004
.
The back substrate
2100
is formed by arranging address electrodes
2102
, barrier ribs
2103
and a phosphor layer
2104
on a back glass plate
2101
. The front substrate
2000
and the back substrate
2001
are then fixed together, and discharge spaces
2200
are formed by introducing a discharge gas into the spaces demarcated by the barrier ribs
2103
. Cells are formed in the discharge spaces
2200
at the points where discharge electrodes
2002
and address electrodes
2102
intersect.
FIG. 42
shows only one such cell, but in fact the PDP normally includes a plurality of cells in which the phosphor layer
2104
is composed of alternating red, green and blue phosphors, enabling a color display to be produced. Note that in the drawing, the discharge electrodes
2002
and the address electrodes
2102
are drawn as if arranged in parallel, but in fact they are arranged at right angles.
A discharge gas, such as a mixture of neon and xenon, is normally enclosed into the discharge spaces
2200
at a pressure of around 500 Torr (6.65×10
4
Pa).
In practice, however, such conventional PDPs have not always been able to achieve satisfactory luminance. In order to improve luminance, it is considered necessary to enclose the discharge gas inside the discharge spaces
2200
at an internal pressure exceeding 500 Torr (6.65×10
4
Pa).
However, with the internal pressure in the discharge spaces
2200
is raised to 760 Torr (1.01×10
5
Pa) or 1000 Torr (1.33×10
5
Pa), for example, gaps are generated between the barrier ribs
2103
formed on the back glass plate
2101
and the front substrate
2000
, while the front and back substrates
2000
and
2100
bulge outwards. This means that neighboring discharge spaces
2200
are no longer effectively divided by the barrier ribs
2103
, causing the display performance of the PDP to deteriorate.
Even if the internal pressure is set at 760 Torr (1.01×10
5
Pa) or less, the barrier ribs
2103
are not connected to the front substrate
2100
, so that external vibrations or vibrations caused by driving the PDP itself bring the barrier ribs
2103
and the front substrate
2000
repeatedly into contact, generating noise.
In order to correct these problems, one related technique has proposed that the topmost edge of the barrier ribs
2103
be coated with a bonding agent before fixing the pair of substrates together to form the discharge spaces
2200
. A gas discharge panel in which gas has been sealed at a higher pressure is produced, realizing an improvement in luminance. Such a procedure is described in Japanese Patent Application No. 9-49006.
However, when a well-known method such as screen-printing is used to apply the bonding agent to the topmost edge of the barrier ribs
2103
, it is difficult to apply the bonding agent equally to the very long and narrow top surfaces of the barrier ribs
2103
without leaving some parts uncovered. In the case of screen-printing, matching an aperture pattern accurately to the shape of the barrier ribs
2103
has proved extremely difficult. As a result, finding a simple method for improving bonding strength, while maintaining display performance and preventing the generation of distortion when the barrier ribs
2103
touch the front substrate
2000
has posed considerable obstacles.
Furthermore, the properties of the dielectric glass layer
2003
covering the electrodes change if exposed to the discharge spaces
2200
. As a result, a protective coat of MgO or similar is usually formed to cover the surface of the dielectric glass layer
2003
, as described above. Even if a protective layer
2004
is applied in this way, however, the tops of the barrier ribs
2103
are connected after the protective layer
2004
has been applied, and so the surfaces of the bonding agent are not covered by the protective layer
2004
. Thus, the properties of the surface of the bonding agent change as a result of exposure to the discharge spaces
2200
. Substances produced by this change pollute the discharge spaces
2200
and are the cause of such problems as rises in discharge voltage, falls in discharge efficiency and deterioration in the phosphors.
DISCLOSURE OF THE INVENTION
The present invention has been developed in view of the above problems in the background art. A first object of the invention is to provide a display panel manufacturing method performed by connecting two substrates together as strongly as possible using a bonding agent, and in particular to provide a simple bonding agent application method for arranging the bonding agent evenly on the narrow areas that form the tops o f the barrier ribs leaving almost no uncovered areas.
A second object of the present invention is to provide a gas discharge display panel capable of preventing changes in the properties of the bonding agent surface caused by discharge.
To fulfill the above first object, a display panel manufacturing method, comprising an application process for applying a bonding agent to a plurality of barrier ribs formed on at least one of a pair of substrates, and a connection process for arranging the pair of substrates together via the bonding agent that has been applied to the barrier ribs is provided. The application process includes a bonding agent layer forming step for forming a layer of a past-like bonding agent having an even surface over a substrate having an even surface; and a connecting step for simultaneously bringing a top of each barrier rib down into contact with the bonding agent layer, while regulating a distance between the upper surface of the bonding agent layer and the barrier ribs.
A display panel manufacturing method may further include an application process for applying a bonding agent to a plurality of barrier ribs formed on at least one of a pair of substrates, and a connection process for arranging the pair of substrates in opposition and connecting the pair of substrates together via the bonding agent that has been applied to the barrier ribs. The application process includes a bonding agent layer forming step for forming a layer of a paste-like bonding agent having an even surface so as to embed a position regulating member that regulates positions of the barrier ribs within the layer, the position regulating member being arranged on a substrate having an even surface; and a connecting step for bringing a top of each barrier rib down into contact with the position regulating member to apply the bonding agent simultaneously to the tops of all of the barrier ribs while regulating a distance between the upper surface of the bonding agent layer and the barrier ribs.
Furthermore, a display panel manufacturing method may include an application process for applying a bonding agent to a plurality of barrier ribs formed on at least one of a pair of substrates in opposition and connecting the pair of substrates together via the bonding agent that has been applied to the barrier ribs. The application process includes a bonding agent layer forming step for forming a layer of a paste-like bonding agent having a curved surface so as to embed a position regulating member that regulates positions of the barrier ribs within the layer, the position regulating member being arranged on a substrate having a curved surface; and a connecting step for bringing a part of each
Hiagshino Hidetaka
Hibino Junichi
Kirihara Nobuyuki
Murai Ryuichi
Nagao Nobuaki
Colón German
Matsushita Electric - Industrial Co., Ltd.
Ramsey Kenneth J.
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