Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
2001-06-15
2004-02-17
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
C445S023000, C445S025000
Reexamination Certificate
active
06692325
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a gas discharge panel which is used for display of images with a computer, television or other device, and a method of production for such a panel. More particularly, the present invention relates to a gas discharge panel which has discharge cells arranged in a matrix layout.
BACKGROUND ART
Recently, gas discharge panels have received attention as a flat-type display for computers, televisions, and other such devices.
Gas discharge panels are categorized broadly as direct-current type (DC type) or alternating-current type (AC type), and at present the AC type, which is suitable for large screens, is the mainstream choice.
In an AC-type gas discharge panel, a discharge cell is illuminated by applying an alternating current pulse to an electrode, which is coated with a dielectric layer to maintain discharge. Two kinds are known, a surface discharge type, which has sustaining electrode pairs arranged in parallel on the front panel side, and an opposed discharge type, which has sustaining electrode pairs arranged in opposition to each other on the front panel and back panel.
FIG. 15
shows an example of a conventional AC plane discharge type gas discharge panel.
This gas discharge panel has a front panel
110
and a back panel arranged opposite each other, sealed around the outer edge with a sealing material composed of low-melting glass to form the gas discharge space. The airtight space
104
formed between the two substrates is filled with an. inert gas (a mixture of helium and xenon) at a pressure of about 300 Torr to 500 Torr (40 kPa to 66.5 kPa).
The front panel
110
has display electrode pairs
112
a
,
112
b
, formed on the opposing face (the side facing the back panel), and has a dielectric layer
113
, composed of dielectric glass, and a protective layer
114
, composed of MgO, formed as a coating over the electrodes.
The back panel
120
has address electrodes
122
patterned on the opposing face (the side facing the front panel), and has a back dielectric layer
123
formed as a coating over the electrodes. Barrier ribs
124
are formed on top of the back dielectric layer
123
, and RGB phosphor layers
131
are formed between adjacent barrier ribs
124
.
The space
140
delimited by the barrier ribs
124
becomes the light-emitting area (discharge cells), and a phosphor layer is applied to each discharge cell. The barrier ribs
124
and address electrodes
122
are formed in the same direction, and the display electrode pairs
112
a
,
112
b
, are perpendicular to the address electrodes
122
.
In this gas discharge panel, after applying an address pulse between the address electrode
122
and the display electrode
112
a
, based on the image data to be displayed, applies a sustaining pulse to the pair formed by the display electrode
112
a
and display electrode
112
b
, thereby selectively causing a sustaining discharge in the discharge cell. In the discharge cell subject to sustaining discharge, ultraviolet rays are produced, visible light is generated and emitted from the RGB-colored phosphor layers
131
, and an image is displayed.
Here, the barrier ribs
124
divide the discharge space into discharge cells, preventing cross-talk (the phenomenon of discharge mixing across the interface of discharge cells).
Since the filling pressure of discharge gas is usually lower than atmospheric pressure, the front glass substrate
111
and back glass substrate
121
are pressed inward by atmospheric pressure. Here, the barrier ribs
124
act as a spacer, maintaining the space between the two substrates, with the peaks of the barrier ribs contacting the inner surface of the front panel
110
.
The following describes a production method for the above gas discharge panel.
For the front panel
110
, display electrodes
112
a
,
112
b
, are formed on the front glass substrate
111
, a dielectric layer
113
is formed by applying and baking a layer of dielectric glass covering the electrodes, and a protective layer
114
is formed by EB evaporation of MgO over the dielectric layer
113
.
For the back panel
120
, address electrodes
122
are formed on the back glass substrate
121
, the back dielectric layer
123
is formed covering the electrodes, and barrier ribs
124
are formed on top of the back dielectric layer
123
.
The barrier ribs
124
may be, for example, formed on the surface of the back dielectric layer
123
, then coated with resist. Next, the resist coating may be patterned in stripes, the unnecessary portion of barrier rib material removed by sand blasting, and the coating then baked.
Next, between barrier ribs
124
, a phosphor paste is potted by printing or other method and baked to form a phosphor layer
131
. This completes production of the back panel
120
.
The front panel
110
and back panel
120
, produced as described above, have a low-melting glass applied as a sealing material around their outer edges, are stacked and sealed by baking, then evacuated and the space between the two panels is filled with an inert gas, completing production of the gas discharge panel.
In this gas discharge panel, it is desirable for color images to be displayed accurately, and for production cost to be low.
It should be noted that the illumination strength of each discharge cell is affected by the shape of the cell. In order to accurately display color images, it is necessary for the discharge cells which are arranged in a matrix to have a uniform shape. This means that it is necessary for the barrier ribs to have uniform height and width. However, if baking occurs after the barrier rib material is applied and coated, the coating will shrink during baking. This causes difficulty in maintaining a uniform height of the barrier ribs and reduces yield. This in turn increases the production cost of gas discharge panels.
DISCLOSURE OF INVENTION
It is therefore an object of the present invention to provide a gas discharge panel which has precise color display and is easily manufactured.
To this end, the gas discharge panel has a first and a second substrate facing each other with a space in between, the space filled with discharge gas to form a discharge space. At least one of the first and second substrates has groups of electrode pairs for sustaining discharge arranged on its surface. The first substrate has phosphor layers arranged on it, such that a plurality of discharge cells is formed in a matrix pattern along the groups of electrode pairs. A gas discharge panel which displays images by selectively illuminating a plurality of discharge cells, incorporates gap members of a certain shape between the first and second substrates, in areas corresponding to the borders between discharge cells, except for the center of the discharge cell. Here, a certain shape means the gap members have a particular shape, such as spherical or rod-shaped, and their shape does not change over the process of panel production, i.e., the gap members do not deform during baking as a paste material does.
According to the present invention, even without forming barrier ribs between the front panel and back panel, the spacing (gap) between the substrates can be precisely prescribed. Also, since the gap members are not placed in the central area of the discharge cells, the gap members do not hinder discharge, and the panel is resistant to discharge failure.
Therefore, it is easier to produce a gas discharge panel which is capable of high-precision image display, at a lower cost than heretofore.
This type of gas discharge panel can be realized through the following processes: (a) a process for arranging a phosphor layer, which corresponds to the illumination color of the discharge cell, in the desired place on one substrate; (b) a a process for affixing gap members of a certain shape on one substrate in a position which corresponds to the border region between discharge cells; and (c) a process for stacking the second substrate on the substrate with the gap members affixed and joining the two substrates.
Here, when forming phosphor layers corresponding to t
Hibino Junichi
Hori Tetsuo
Ookawa Masafumi
Sasaki Yoshiki
Yamashita Katuyoshi
Leurig Sharlene
Patel Nimeshkumar D.
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