Electric lamp and discharge devices – With luminescent solid or liquid material – Vacuum-type tube
Reexamination Certificate
1998-10-19
2001-03-20
Day, Michael H. (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Vacuum-type tube
C313S497000, C313S306000, C313S307000, C313S311000
Reexamination Certificate
active
06204600
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a field emission device and an image display device using the same.
2. Description of the Related Art
In order to find a substitute for the existing cathode ray tube (CRT), there has been vigorous research into development of flat panel displays, and the flat panel displays are being extensively developed to apply the same to a wall television and an image display for a high definition television (HDTV). Such flat panel displays include a liquid crystal device, a plasma display panel and a field emission device. Among those, much attention has been paid to the field emission device due to its brightness and low power consumption.
The conventional field emission device includes a cathode layer formed on a substrate in a predetermined pattern, microtips formed on the cathode layer, an insulation layer formed on the cathode layer to expose the microtips, and a gate electrode having an aperture exposing the microtips on the insulation layer.
If a predetermined voltage is applied between anodes (not shown) installed over the gate electrodes and microtips in a state where the microtips are grounded, electrons are emitted from the microtips. The field emission device has a short life because the microtips are susceptible to damage due to ion collision. Also, much electricity is consumed due to a high voltage for forming an electric field. A large amount of Joule heat is generated during electron emission, which may cause thermal deterioration of the device.
FIG. 1
illustrates an example of an image display device using a field emission device proposed for solving the problems of the conventional art.
As shown in
FIG. 1
, first and second electrodes
12
and
13
are formed to be spaced a predetermined distance apart from each other on the top surface of a rear substrate
11
. Thin layers
14
a
and
14
b
formed of PdO are coated on the first and second electrodes
12
and
13
, respectively. Also, a transparent front substrate
15
is coupled over the rear substrate
11
to form a free space for electron movement between the same and the rear substrate
11
. A phosphor layer
16
and an accelerating electrode layer
17
are sequentially formed on the bottom surface of the front substrate
15
.
In the operation of the field emission device
10
constructed as described above, a high voltage is applied to the accelerating electrode layer
17
and a predetermined voltage is applied to the first and second electrodes
12
and
13
, so that electrons emitted between the thin layers
14
a
and
14
b
coated on the respective electrodes
12
and
13
are accelerated toward the accelerating electrode layer
17
to make the phosphor layer
16
luminesce.
However, the conventional field emission device has disadvantages in that it is difficult to maintain a small distance between thin layers
14
a
and
14
b,
for example to 10 nm, and there is a limit in selecting materials for forming thin layers and electrodes. Also, due to a complicated process for forming the thin layers, a large-screen image display device is difficult to fabricate.
SUMMARY OF THE INVENTION
To solve the above problems, it is an objective of the present invention to provide a field emission device which can reduce the driving voltage and can be fabricated to be large, and a display device employing the same.
Accordingly, to achieve the above objective, there is provided a field emission device including a substrate, a first electrode formed on the substrate in a predetermined pattern, a dielectric layer formed on the substrate to embed the first electrode, a second electrode formed on the dielectric layer in a predetermined pattern, a floating electrode spaced apart a predetermined distance from the second electrode, on the dielectric layer, and a conductive particle layer formed between the second electrode and the floating electrode to electrically connect the second electrode and the floating electrode.
The conductive particle layer is formed by hardening a paste containing conductive particles so that the conductive particles are dispersed and spaced apart from one another.
Preferably, the capacitance between the first electrode and the floating electrode is greater than that between the first electrode and the second electrode.
According to another aspect of the present invention, there is provided a display device comprising a field emission device including a substrate, a first electrode formed on the substrate in a predetermined pattern, a dielectric layer formed on the substrate to embed the first electrode, a second electrode formed on the dielectric layer in a predetermined pattern, a floating electrode spaced apart a predetermined distance from the second electrode, on the dielectric layer, and a conductive particle layer formed between the second electrode and the floating electrode to electrically connect the second electrode and the floating electrode; and a front substrate coupled in front of the substrate to form a space for electron emission with the substrate and having a phosphor layer and an accelerating electrode layer sequentially formed in its inner surface.
REFERENCES:
patent: 5455597 (1995-10-01), Nakamura et al.
patent: 5932963 (1999-08-01), Nakamura et al.
patent: 6005334 (1999-12-01), Mitome et al.
patent: 6043605 (2000-03-01), Park
patent: 0 675 517 (1995-10-01), None
patent: 97 11476 (1997-03-01), None
Choi Jong-seo
Park Deuk-il
Day Michael H.
Lowe Hauptman & Gilman & Berner LLP
Samsung Display Devices Co. Ltd.
Santiago Mariceli
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