Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2001-05-18
2003-10-07
Hjerpe, Richard (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S077000, C345S690000
Reexamination Certificate
active
06630918
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to plasma display panels and more particularly to a compensation method for improving color purity and color temperature of plasma display panel by adjusting the strength of input image signals.
BACKGROUND OF THE INVENTION
A manufacturing process of a conventional alternating current discharge type plasma display panel (PDP)
10
is shown in FIG.
1
. First, two different activation layers are formed on glass substrates
11
and
12
respectively. Then seal the peripheries of the glass substrates together. A mixed gas consisting of helium (He), neon (Ne), and xenon (Xe) (or argon (Ar)) having a predetermined mixing volume ratio is stored in a discharge space formed in between the glass substrates. A front plate
11
is defined as one that facing viewers. A plurality of parallel spaced transparent electrodes
111
, a plurality of parallel spaced bus electrodes
112
, a dielectric layer
113
, and a protective layer
114
are formed from the front plate
11
inwardly. From a corresponding rear plate
12
inwardly, a plurality of parallel spaced data electrodes
121
, a dielectric layer
124
, a plurality of parallel spaced ribs
122
, and a uniform phosphor layer
123
are formed. When a voltage is applied on electrodes
111
,
112
, and
121
, dielectric layers
113
and
124
will discharge in discharge cell
13
formed by adjacent spaced ribs
122
. As a result, a ray having a desired color is emitted from phosphor layer
123
.
Conventionally, in PDP
10
a plurality of parallel spaced transparent electrodes
111
are formed on inner surface of front plate
11
by sputtering and photolithography (or printing). Then a plurality of parallel spaced bus electrodes
112
are formed on the transparent electrodes
111
respectively by plating (or sputtering) and photolithography. The line impedance of the transparent electrodes
111
may be reduced by the provision of bus electrodes
112
. In the following description, two adjacent transparent electrodes
111
(including bus electrodes
112
) on the front plate
11
are represented by X electrode and Y electrode respectively. A triple electrode is formed by X electrode, Y electrode and corresponding data electrode
121
on the rear plate
12
. When a voltage is applied on the triple electrode, dielectric layers
113
and
124
will discharge in discharge cell
13
formed by adjacent spaced ribs
122
. Hence, UV rays are emitted from the mixed gas stored therein. And in turn, phosphor layer
123
in discharge cell
13
is activated by the UV rays. As an end, a visible light is generated by red, green and blue phosphor layers, resulting in an image showing.
In the conventional PDP
10
, a mixed gas (which is a combination of neon (Ne) and xenon (Xe), a combination of helium (He), neon (Ne) and xenon (Xe), a combination of neon (Ne), xenon (Xe), and argon (Ar), or a combination of helium (He), neon (Ne), xenon (Xe) and argon (Ar)) is used. Note that neon (Ne) is the indispensable constituent component of any of the above combinations. When a discharge is occurred in any of the above combinations, an orange red of visible light O
g
having a wavelength of about 586 nm is generated as shown in
FIGS. 2
a
and
2
b
. Note that the color of the visible light emitted during discharging may be one other than orange red if the combination of the mixed gas is changed. Such orange red of visible light generated by the gas in each of red, green, and blue discharge cells inevitably and adversely affects the color purity of PDP
10
and results in a lowering of color temperature of PDP
10
.
Conventionally, as to the poor color purity and low color temperature of PDP caused by orange red of visible light during gas (mainly by Ne) discharging in discharge cell
13
, a number of improvements have been proposed by PDP manufacturers to mitigate the above problems. For example, NEC (Japan) implements a capsulated color filter technique. A filter
20
on front plate
11
is formed on each of corresponding red, green, and blue discharge cells
13
as shown in FIG.
3
. With this, it is possible to filter out the orange red of visible light O
g
from discharge cells
13
, thereby increasing color purity and color temperature of PDP. However, the manufacturing cost is increased significantly because the manufacturing process of filters
20
is complex and the precision requirement is much higher. Another improvement technique is proposed by Matsushita (Japan) in which the sizes of red, green, and blue discharge cells
13
are made different one another as shown in FIG.
4
. The size of blue discharge cell
13
is the largest among all discharge cells
13
for increasing color temperature of PDP. Also, the size of red discharge cell
13
is the smallest among all for decreasing the affecting degree on the color temperature of PDP. However, the manufacturing process is complex. Further, there is a great difficulty in driving such device.
In view of the above, such conventional improvements are disadvantageous for the complex process and undesirable design of PDP since the construction of PDP is changed for eliminating the adverse effect of the generated orange red of visible light on the color purity and color temperature of PDP. Thus, it is desirable to provide a novel method for improving color purity and color temperature of PDP in order to overcome the above drawbacks of prior art.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a compensation process for improving color saturation and image quality of a plasma display panel (PDP), wherein a brightness of light generated from each of red, green, and blue discharge cells of each pixel on said PDP is calculated through a numeric operation according to laws of color matching, the process comprising the step of increasing or decreasing the strength of input image signals of each of the red, green, and blue discharge cells in accordance with the calculation result for adjusting the brightness of the generated red, green, and blue lights so as to subtract a visible light generated by the gas in each of the red, green, and blue discharge cells during gas discharging, thereby eliminating an adverse effect of the visible light on color purity and color temperature of the PDP during gas discharging.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.
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patent: 6094185 (2000-07-01), Shirriff
patent: 6204833 (2001-03-01), Hayashi et al.
patent: 6229582 (2001-05-01), Van Slooten
patent: 6271825 (2001-08-01), Greene et al.
patent: 6304254 (2001-10-01), Johnson et al.
patent: 6411306 (2002-06-01), Miller et al.
patent: 6414660 (2002-07-01), Kasahara et al.
patent: 6489965 (2002-12-01), Voorhies
Chen Kuang-Lang
Kao Shiuh-Bin
Lai Yao-Hung
Lin Ching-Hui
Bacon & Thomas PLLC
Chunghwa Picture Tubes Ltd.
Fatahi-yar M.
Hjerpe Richard
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