Plasma display panel

Details Plasma display panel Plasma display panel

2002-03-28

2004-06-29

Patel, Ashok (Department: 2879)

Electric lamp and discharge devices

With gas or vapor

Three or more electrode discharge device

C313S586000

Reexamination Certificate

active

06756733

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a plasma display panel having an improved structure so that visual rays having high brightness is generated at a low discharge voltage and deterioration of a fluorescent substance can be reduced.
2. Description of the Related Art
Plasma display panels are apparatuses for displaying desired numbers, letters or graphic by exciting fluorescent substances by ultraviolet rays generated from plasma.
The plasma display panel is classified into a DC type and an AC type according to the type of a driving voltage applied to a discharge cell, for example, the types of discharge.
In a DC type plasma display panel, all electrodes are exposed to a discharge space so that electric charges are moved directly between the corresponding electrodes. In an AC type plasma display panel, at least one electrode is covered with a dielectric layer and electric charges do not move directly between corresponding electrodes. Instead, discharge is performed by wall charges.
An example of an AC type plasma display panel is shown in
FIGS. 1 and 2
. Referring to the drawings, a plurality of first electrodes
12
are formed parallel to one another in the first direction on an inner surface of a rear substrate
10
. A first dielectric layer
14
is formed on the inner surface of the rear substrate
10
to cover the first electrodes
12
. A plurality of barrier ribs
16
for sustaining a discharge distance and preventing electric, optical crosstalk between neighboring discharge cells are formed on an upper surface of the first dielectric layer
14
between the first electrodes
12
. Also, a fluorescent substance layer
18
is formed on the upper surface of the first dielectric layer
14
and the side surfaces of the barrier ribs
16
.
A front substrate
20
is coupled to the rear substrate
10
to form a discharge space sectioned by the barrier ribs
16
. A plurality of second electrodes
13
are formed parallel to one another and perpendicular to the first electrodes
12
on an inner surface of the front substrate
20
. A second dielectric layer
15
is formed on the inner surface of the front substrate
20
to cover the second electrodes
13
. A protective film
25
is formed on a surface of the second dielectric layer
20
. The discharge space formed by coupling the front substrate
20
and the rear substrate
10
is filled with a discharge gas
30
which generates ultraviolet rays during discharge.
The dielectric layers
14
and
15
achieve a high discharge intensity and a memory effect by repeating an electron avalanche phenomenon of wall charges charged on the surface of the dielectric layers. Meanwhile, since the dielectric layers
14
and
15
formed in a thick film method such as print is not dense, plasma intrudes into the dielectric layers through gaps and damages the electrodes (ion bombardment phenomenon). Thus, the protective film
25
prevents the ion bombardment phenomenon and is formed into a dense structure in a thin film method such as deposition. Here, the protective film
25
is formed of MgO having a superior secondary electron emission effect in a deposition method. The MgO protective film not only prevents damage to the dielectric layers due to sputtering of plasma particles, but also lowers a discharge voltage and a sustain voltage by the secondary electron emission. Also, a discharge gas
30
sealed in the discharge space generates ultraviolet rays having a wavelength of about 147 nm during discharge. In general, a penning gas mixture of He, Ne, Ar, or a gas mixture thereof, and a small amount of Xe gas which becomes a source of the generation of ultraviolet rays is used as the discharge gas.
However, the plasma display panel having the above structure cannot prevent deterioration of the fluorescent substance due to ion collision generated on the rear substrate. Also, since the ultraviolet rays are projected toward the rear substrate to excite the fluorescent substance layer and then visual rays generated thereby is reflected by a reflection layer of the rear substrate and projected toward the front substrate, the dielectric layer and electrodes located on the front substrate serve as an obstruction transmission of light so that brightness is lowered.
SUMMARY OF THE INVENTION
To solve the above-described problems, it is an object of the present invention to provide a plasma display panel in which a discharge space is filled with a discharge gas including a gas generating ultraviolet rays having a long wavelength during discharge, and a fluorescent substance layer and a protective film are independently formed on each of the front and rear substrates, so that brightness increases, a discharge voltage is reduced, and deterioration of the fluorescent substance is prevented.
To achieve the above object, there is provided a plasma display panel comprising a front substrate and a rear substrate arranged separated a predetermined distance from each other and to face each other, forming a discharge space, a plurality of first electrodes formed on an inner surface of the rear substrate, a first dielectric layer formed on the inner surface of the rear substrate to cover the first electrodes, a plurality of barrier ribs formed between the first electrodes on the inner surface of the rear substrate, sectioning the discharge space, a fluorescent substance layer formed on a surface of the first dielectric layer and side surfaces of the barrier ribs, a first protective film formed on a surface of the fluorescent substance layer, a plurality of second electrodes formed corresponding to the first electrodes on an inner surface of the front substrate, a second dielectric layer formed on the inner surface of the front substrate to cover the second electrodes, a second protective film formed on the surface of the second dielectric layer, and a predetermined discharge gas sealed in the discharge space.
To achieve the above object, there is provided a plasma display panel comprising a front substrate and a rear substrate arranged separated a predetermined distance from each other and to face each other, forming a discharge space, a plurality of first electrodes formed on an inner surface of the rear substrate, a first dielectric layer formed on the inner surface of the rear substrate to cover the first electrodes, a plurality of barrier ribs formed between the first electrodes on the inner surface of the rear substrate, sectioning the discharge space, a first fluorescent substance layer formed on a surface of the first dielectric layer and side surfaces of the barrier ribs, a plurality of second electrodes formed corresponding to the first electrodes on an inner surface of the front substrate, a second dielectric layer formed on the inner surface of the front substrate to cover the second electrodes, a second fluorescent substance layer formed on a surface of the second dielectric layer, a second protective film formed on the surface of the second dielectric layer, and a predetermined discharge gas sealed in the discharge space.
It is preferred in the present invention that the plasma display panel further comprises a first protective film formed on a surface of the first fluorescent substance layer.
It is preferred in the present invention that the discharge gas includes a gas generating ultraviolet rays having a long wavelength of 147 nm or more during discharge.
It is preferred in the present invention that the discharge gas includes a gas generating ultraviolet rays having a long wavelength of 200 nm or more during discharge.
It is preferred in the present invention that the thickness of the first protective film is 100 through 500 nm.
It is preferred in the present invention that the thickness of the second fluorescent substance layer is 1 through 20 &mgr;m.


REFERENCES:
patent: 6611099 (2003-08-01), Murata et al.
patent: 2002/0063526 (2002-05-01), Mizobata

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