Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making named article
Reexamination Certificate
2001-09-19
2002-08-06
McPherson, John A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making named article
C430S323000, C445S024000
Reexamination Certificate
active
06428945
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of forming barrier ribs in a plasma display panel (PDP) and, more particularly, to a method of forming barrier ribs with different depths.
2. Description of the Related Art
A plasma display panel (PDP) is a thin type display, usually has a large display area and a thin thickness. The luminescent principle of the PDP is the same as that of a fluorescent lamps. A vacuum glass trough is filled with inert gases. When a voltage is applied to the glass trough, some plasma will be occurred to radiate ultraviolet (UV) rays. After the fluorescent materials coated on the wall of the glass trough adsorb the UV rays, the fluorescent materials will radiate visible light including red light, green light and blue light. A plasma display can be viewed as a combination of hundreds of thousands of illuminating units, each illuminating unit has three subunits for radiating red light, green light and blue light, respectively. Images will be showed on the display by mixing these three primary colors.
As shown in
FIG. 1
, a conventional PDP
10
has a pair of glass substrates
12
,
14
arranged in parallel and opposite to each other. A discharge space
16
is formed between the glass substrates
12
,
14
and injected with inert gases, such as Ar, Xe or others. The upper glass substrate
12
has a plurality groups of transverse electrodes positioned in parallel. Each group of the transverse electrodes has a first and a second sustaining electrode
18
,
20
, and each sustaining electrode
18
,
20
includes a transparent electrode
181
,
201
and a bus electrode
182
,
202
. A dielectric layer
24
is further formed to cover these transverse electrodes, and a protection layer
26
is formed on the dielectric layer
24
.
The lower glass substrate
14
has a plurality of barrier ribs
28
arranged in parallel and spaced a distance to each other for dividing the discharge space
16
into a plurality of group of sub-discharge spaces. Each group of the sub-discharge spaces includes a red discharge space
16
R, a green discharge space
16
G, and a blue discharge space
16
B. Also, the lower glass substrate
14
has a plurality of lengthwise electrodes
22
positioned in parallel and between two adjacent barrier ribs
28
to serve as address electrodes. In addition, a red fluorescent layer
29
R, a green fluorescent layer
29
G, and a blue fluorescent layer
29
B will be respectively coated on the lower glass substrate
14
and the sidewalls of the barrier ribs
28
within each red discharge space
16
R, each green discharge space
16
G, and each blue discharge space
16
B.
When a voltage applied for driving these electrodes, the inert gases in the discharge space
16
will be discharged to produce UV rays. The UV rays further illuminate the fluorescent layers
29
R,
29
G,
29
B to radiate visible lights including red light, green light and blue light. After the three primary colors are mixed at different ratios, various images are formed and transmitted through the upper glass substrate
12
.
Considering the illuminant characteristics and the color purities of these three primary colors, some specific materials are used in the fluorescent layers
29
R,
29
G,
29
B. For example, the red fluorescent layer
29
R is formed by mixing Eu
+3
and (Y,Gd)BO
3
, or Eu and Y
2
O
3
. The green fluorescent layer
29
G is formed by mixing Mn and Zn
2
SiO
4
or Mn and BaAl
12
O
19
. The blue fluorescent layer
29
B is formed by mixing Eu
+2
and BaMgAl
14
O
23
, or by Eu
+2
and SrMg (SiO
4
)
2
. However, the fluorescent materials still have some disadvantages. For example, the lifetime of the blue fluorescent materials is too short, and the residual light produced by the green fluorescent materials exists too long. Therefore, the color temperature of the prior PDP
10
is too low, resulting in a poor quality of the display. In order to improve the quality, the widths of different discharge space are varied. The width of the blue discharge space is the biggest so as to increase the blue discharge space
16
B to the maximum space. Thereby, the surface area of the blue fluorescent layer
29
B can be increased to improve the property of blue light. Further, the color temperature of the PDP
10
can be increased to improve the quality of the display. However, the width of the red discharge space
16
R may be reduced too much, and therefore, the processes of manufacturing the barrier ribs
28
and coating the red fluorescent layer
29
R become more difficult. An alignment problem of the glass substrates
12
,
14
is encountered because the width of the red discharge space
16
R is small. In addition, the discharged gases may be flowed to the neighbor cells to cause a “cross-talk” phenomenon when the width of the red discharge space
16
R is narrow. The electrical properties of the PDP
10
are then changed. In order to solve the problems described above, a method of forming the PDP with a high color temperature should be disclosed.
SUMMARY OF THE INVENTION
The present invention is a method of forming barrier ribs of a PDP with different depths of the discharge spaces.
The barrier ribs are formed on a substrate having a plurality of electrodes, a dielectric layer above the electrodes and the substrate, and a rib material layer on the dielectric layer. First, a first bottom pattern layer, a second bottom pattern layer and a third bottom pattern layer are formed above the rib material layer. These bottom pattern layers have the same width and are spaced apart to each other with the same distance. Second, a first middle pattern layer, a second middle pattern layer and a third middle pattern layer are respectively formed on the first bottom pattern layer, the second bottom pattern layer and the third bottom pattern layer. The left sidewalls of the first middle pattern layer and the first bottom pattern layer are aligned. The right sidewalls of the second middle pattern layer and the second bottom pattern layer are aligned. Both of the right and left sidewalls of the third middle pattern layer and the third bottom pattern layer are respectively aligned. Then, a first top pattern layer and a second top pattern layer are respectively formed on the first middle pattern layer and the third middle pattern layer. The left sidewalls of the first top pattern layer and the first middle pattern layer are aligned. The right sidewalls of the second top pattern layer and the third middle pattern layer are aligned. Next, a sandblasting process is performed by using the bottom pattern layers, the middle pattern layers, and the top pattern layers as a mask, so that parts of the rib material layer are removed to expose parts of the dielectric layer. Finally, the barrier ribs are formed after removing the bottom pattern layers, the middle pattern layers, and the top pattern layers.
Accordingly, it is a principle object of the invention to provide the barrier ribs with different depths.
It is another object of the invention to adjust the surface areas of fluorescent materials coated on different discharge spaces.
Yet another object of the invention is to adjust the depths of different discharge spaces.
It is a further object of the invention to increase the color temperature of the PDP.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.
REFERENCES:
patent: 5990617 (1999-11-01), Kanae et al.
patent: 4-282531 (1992-10-01), None
patent: 5-128966 (1993-05-01), None
Chou Chung-Wang
Lin Chien-Ho
Au Optronics Corp.
Ladas & Parry
McPherson John A.
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