Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2002-08-23
2004-08-24
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S112000, C313S117000
Reexamination Certificate
active
06781310
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma display panel, and in particular to a plasma display panel which is capable of improving colorimetric purity by selectively filtering and outputting only visible light of request color.
2. Description of the Prior Art
In general, a plasma display panel is for displaying images by using visible light generated from a fluorescent layer after exciting the fluorescent layer with ultraviolet light of plasma.
In the meantime, in the conventional plasma display panel, by near infrared light or visible light generated from discharge gas and outer visible light irradiated from the outside and reflected, a contrast may be lowered. Accordingly, in order to improve the contrast, a color filter is mounted onto the plasma display panel.
When the color filter is mounted onto the plasma display panel, because fabrication process is complicated, yield rate is lowered, and accordingly a production cost is increased. Hereinafter, a structure of the conventional plasma display panel will be described with reference to accompanying FIG.
1
.
FIG. 1
is a sectional view illustrating a structure of a plasma display panel using a color filter in accordance with the conventional art.
As depicted in
FIG. 1
, the conventional plasma display panel includes an insulating layer
9
formed onto a lower glass substrate
10
; an address electrode
11
formed at a certain portion of the insulating layer
9
; a lower dielectric layer
8
formed onto the front surface of the address electrode
11
and the insulating layer
9
; a barrier rib
7
defined at a certain portion of the lower dielectric layer
8
to divide each discharging cell; a black matrix layer
12
formed onto the barrier rib
7
; a fluorescent layer
13
formed at the side surface of the first black matrix layer
12
and the barrier rib
7
and the front surface of the lower dielectric layer
8
so as to have a certain thickness in order to emit each red, green and blue visible light by receiving ultraviolet light; an upper glass substrate
2
; a sustain electrode
3
formed at a certain portion of the upper glass substrate
2
so as to cross the address electrode
11
vertically; a bus electrode
5
formed at a certain portion of the sustain electrode
3
; an upper dielectric layer
4
formed at the front surface of the bus electrode
5
, the sustain electrode
3
and the upper glass substrate
2
; a protecting layer
6
formed onto the upper dielectric layer
4
to protect the upper dielectric layer
4
; and a color filter
1
installed at the upper front surface of the upper glass substrate
2
, filtering colors displayed by each pixel and transmitting the filtered colors. Hereinafter, the operation of the conventional plasma display panel will be described.
First, in the conventional plasma display panel, by potential difference between the address electrode
11
and the bus electrode
5
, discharge gas within a pixel region defined by the barrier rib
7
is in a plasma state, the fluorescent layer
13
is excited by ultraviolet light of the plasma, visible light is generated by the excitation of the fluorescent layer
13
, and an image is displayed by using the visible light. In more detail, by exciting the fluorescent layer
13
by using ultraviolet light generated by Xe gas among discharge gases such as He gas, Xe gas, Ne gas, etc. filled in the discharge space defined by the barrier rib
7
, an expected color can be displayed.
In addition, the Ne gas is filled in the discharge space in order to prevent thermal deformation phenomenon of the dielectric layer
4
or the fluorescent layer
13
occurred by collision of accelerated gas ions.
However, because the Ne gas emits orange color visible light, it lowers colorimetric purity and contrast of the plasma display panel. Accordingly, in the conventional plasma display panel, the color filter
1
is installed in order to prevent orange color visible light emitted by the Ne gas discharge. Herein, the color filter
1
only filters color of each pixel and consists of color layers
1
A~
1
C for transmitting the filtered color and a cutting layer
1
D formed between the color layers and cutting off light.
When the color filter
1
is applied to the plasma display panel, reflection rate of visible light irradiated from the outside of the plasma display panel can be improved, and accordingly contrast of the plasma display panel can be improved.
However, in application of the color filter
1
to the plasma display panel, fabrication process is complicated, yield rate is lowered, and accordingly a production cost is increased.
In the meantime, other conventional plasma display panels and fabrication methods thereof are disclosed in U.S. Pat. No. 5,838,106 (Nov. 17, 1998), in U.S. Pat. No. 6,242,859 (May 6, 2001) and in U.S. Pat. No. 6,344,080 (Feb. 5, 2002).
As described above, in the conventional plasma display panel, in use of the color filter
1
, contrast can be improved, however, fabrication process is complicated, yield rate is lowered, and accordingly a production cost is increased.
In addition, in the conventional plasma display panel, the color filter
1
may lower light efficiency of the plasma display panel by light transmittivity of the color layer thereof.
SUMMARY OF THE INVENTION
In order to solve the above-mentioned problem, it is an object of the present invention to provide a plasma display panel which is capable of improving colorimetric purity without lowering light efficiency by selectively filtering only visible light of request color.
In order to achieve the above-mentioned object, a filter of a plasma display panel includes a grating layer having plural gratings for diffracting lights generated in a plasma display panel at a certain angle and a black matrix layer for transmitting or cutting off the lights diffracted by the grating layer.
In order to achieve the above-mentioned object, in a plasma display panel including an upper glass substrate, a first electrode, an upper transparent dielectric layer and a protecting layer sequentially formed onto the upper glass substrate, a lower glass substrate formed with a certain distance from the upper glass substrate, a second electrode, a lower transparent dielectric layer, an barrier rib and a fluorescent layer sequentially formed onto the lower glass substrate, a plasma display panel further includes a filter consisting of a grating layer having plural gratings for diffracting lights generated in a plasma display panel at a certain angle and a black matrix layer transmitting or cutting off the lights diffracted by the grating layer.
REFERENCES:
patent: 5838106 (1998-11-01), Funada
patent: 6242859 (2001-06-01), Betsui et al.
patent: 6344080 (2002-02-01), Kim et al.
patent: 6429587 (2002-08-01), Sugimachi et al.
patent: 6559592 (2003-05-01), Lee
patent: 6630789 (2003-10-01), Hirota et al.
Lee Hong Degerman Kang & Schmadeka
LG Electronics Inc.
Patel Ashok
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