Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
2002-01-11
2003-09-02
Ramsey, Kenneth J. (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S495000, C313S496000, C313S497000, C445S025000
Reexamination Certificate
active
06614168
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a package structure of a display, and especially to a package structure of a field emission display.
BACKGROUND OF THE INVENTION
There are many kinds of displays, such as liquid crystal display (LCD), field emission display and plasma display. These displays in accordance with their features are applied in the portable computers, personal digital assistants and color televisions. With the advance of techniques for manufacture and design, these displays have been introduced into the field, and have gradually replaced the CRT used for conventional display.
The structure of a field emission display (FED) is shown in FIG.
1
and includes the cathode plate
122
and anode plate
120
. The anode plate
120
includes the upper glass substrate
100
whereon a layer of fluorescence material
102
is deposited. The cathode plate
122
includes the lower glass substrate
110
where the emitter layer
104
is deposited or coated. The side glasses
106
are used to separate the anode plate
120
from the cathode plate
122
by a distance of about 0.5 mm to 2 mm. Photolithography or laser process is used to fix the location of the side glasses
106
on the upper glass substrate
100
or the lower glass substrate
110
. Next, glass frits
108
is used to bond the side glasses
106
on the upper glass substrate
100
or the lower glass substrate
110
. If the side glasses
106
are bound on the upper glass substrate
100
, after aligning the lower glass substrate
110
, the glass frits
108
is applied to the adjoining part of the side glasses
106
and the lower glass substrate
100
to adhere them to each other. The two glass substrates
100
and
110
may be adhered to each other by this way.
In the high vacuum situation, when an electric voltage difference exists between the two glass substrates
100
and
110
, the field emitting electrons of the emitter
104
are attracted out of the cathode plate
122
and accelerated to hit the fluorescence material
102
of the anode plate
120
, causing luminescence. Therefore, after accomplishing the whole package process, an exhausting process must be performed to achieve a vacuum degree lower than the 10
−6
torr between the two glass substrates
100
and
110
. This ensures that the field emitting electrons are not affected by the residual gas thereof. The residual gas may reduce the efficiency of luminescence and the life time of emitters
104
.
In the conventional package technology, first, the side glasses
106
are fixed on the upper glass substrate
100
or the lower glass substrate
110
. Next, the glass frits
108
is applied to the side glasses
106
, after aligning the two glass substrates, to adhere one to the other to finish the package process. However, because the glass frits is used on the two ends of the side glasses
106
, at least the following drawbacks exist in the conventional package process:
(1) If the glass frits
108
is not uniformly applied to the side glasses
106
, stress may cause the two glass substrates to break during the package process.
(2) After the package alignment process is finished, the whole structure undergoes a thermal cyclecycle. The glass frits
108
is in a fusion state during the thermal cyclecycle. If the glass frits
108
is not uniformly applied to the side glasses
108
, the two glass substrates
100
and
110
may shift by shear stress, resulting in misalignment.
(3) Even if the misaligned glass substrates pass safely through the thermal cycle, the probability of breakage during use will increase due to the non-uniform glass frits
108
SUMMARY OF THE INVENTION
It is difficult to apply the glass frits uniformly to the side glasses in the conventional package method of the field emission display. As a result, the following processes will be affected. For example, in the process of aligning the two-glass substrates package process, the non-uniform glass frits may cause the two glass substrates to break. If the package alignment process is finished, misalignment between the two glass substrates usually happens because the non-uniform glass frits causes the two glass substrates to slide in the subsequent thermal cycle. Even after the thermal cycle, the non-uniform glass frits increases the breakage probability of the two glass substrates during use because of residual stress. Therefore, the main purpose of the present invention is to provide a package structure of the field emission display to resolve the foregoing drawbacks.
In accordance with the foregoing purpose, the present invention discloses a package structure of field emission display. In accordance with the present invention, first, photolithography or laser process is used to fix the location of the side glasses on the anode plate and the cathode plate. When performing package process, the side glasses are used to separate the anode plate from the cathode plate by a distance. After the alignment process, the glass frits is used to fill the gap between the side glasses respectively belonging to the anode plate and the cathode plate. Next, the whole structure undergoes a thermal cycle at a temperature of about 300 to 450° C. Through the thermal cycle the side glasses are adhered to each other by the glass frits so that the anode plate and the cathode plate may be sealed. When a electric voltage difference exist between the two plates, the electrons of the cathode plate are attracted out of the plate and are accelerated to hit the fluorescence material of the anode plate to cause luminescence in vacuum environment.
REFERENCES:
patent: 5336121 (1994-08-01), Baret
patent: 5754003 (1998-05-01), Murai et al.
patent: 5876260 (1999-03-01), Pepi et al.
patent: 6006003 (1999-12-01), Kim
patent: 2000311630 (2000-11-01), None
Hsiao Ming-Chun
Lee Cheng-Chung
Industrial Technology Research Institute
Ramsey Kenneth J.
Santiago Mariceli
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