Batteries: thermoelectric and photoelectric – Thermoelectric – Adjuncts
Reexamination Certificate
2000-10-30
2002-06-25
Bell, Bruce F. (Department: 1741)
Batteries: thermoelectric and photoelectric
Thermoelectric
Adjuncts
C136S203000, C136S205000, C313S582000
Reexamination Certificate
active
06410841
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a plasma display panel, and more particularly to a thermal evolving method and apparatus for a plasma display panel method that is adaptive for reducing a noise as well as a thickness of the plasma display panel.
2. Description of the Related Art
Generally, a plasma display panel (PDP) is a light-emitting device which displays a picture using a gas discharge phenomenon within the cell. This PDP does not require providing an active device for each cell like a liquid crystal display (LCD). Accordingly, the PDP has a simple fabrication process and hence has the advantage of providing a large-dimension screen.
Such a PDP has a number of discharge cells arranged in a matrix type. The discharge cells are provided at each intersection between sustaining electrode lines for sustaining a discharge and address electrode lines for selecting the cells to be discharged.
Referring to
FIG. 1
, each cell of the AC-type, three-electrode PDP includes a front substrate
10
provided with a sustainng electrode pair
12
A and
12
B, and a rear substrate
18
provided with an address electrode
20
. The front substrate
10
and the rear substrate
18
are spaced in parallel to each other with barrier ribs
24
therebetween and sealed with a frit glass. A mixture gas, such as Ne—Xe or He—Xe, etc., is injected into a discharge space defined by the front substrate
10
, the rear substrate
18
and the barrier ribs
24
. Two sustaining electrodes
12
A and
12
B make a sustaining electrode pair within a single plasma discharge channel. Any one electrode of the sustaining electrode pair
12
A and
12
B is used as a scanning electrode that responds to a scanning pulse applied in an address interval to cause an opposite discharge along with the address electrode
20
while responding to a sustaining pulse applied in a sustaining interval to cause a surface discharge along with the other adjacent sustaining electrode. Also, the sustainng electrode
12
B or
12
A adjacent to the sustaining electrode
12
A or
12
B used as the scanning electrode is used as a common sustaining electrode to which a sustaining pulse is applied commonly.
The sustaining electrode pair
12
A and
12
B includes transparent electrodes
30
A and
30
B and metal electrodes
28
A and
28
B connected electrically to each other, respectively. The transparent electrodes
30
A and
30
B are formed by depositing indium thin oxide (ITO) on the front substrate
10
. The metal electrodes
28
A and
28
B are deposited on the front substrate
10
to have a three-layer structure of Ag or Cr—Cu—Cr. The metal electrodes
28
A and
28
B play a role to reduce a voltage drop caused by the transparent electrodes
30
A and
30
B.
On the front substrate
10
provided with the sustaining electrodes
12
A and
12
B, a dielectric layer
14
and a protective layer
16
are disposed. The dielectric layer
14
is responsible for limiting a plasma discharge current as well as accumulating a well charge during the discharge. The protective layer
16
prevents a damage of the dielectric layer
14
caused by the sputtering generated during the plasma discharge and improves the emission efficiency of secondary electrons. This protective layer
16
is usually made from MgO. The rear substrate
18
is provided with a dielectric thick film
26
covering the address electrode
20
. The barrier ribs
24
for dividing the discharge space are extended perpendicularly at the rear substrate
18
. On the surfaces of the rear substrate
18
and the barrier ribs
24
, a fluorescent material
22
excited by a vacuum ultraviolet lay to generate a visible light is coated.
Since such a PDP takes advantages of a gas discharge upon driving, it inevitably generates a high-temperature heat. This high-temperature heat makes an adverse affect to a stable driving and a life of the PDP. In order to evolve such a high-temperature heat into the exterior of the PDP, the PDP is provided with a thermal evolving apparatus. This thermal evolving apparatus evolves a heat generated from the PDP into the exterior by a ventilation system using a fan like other electronic devices.
Referring to FIG.
2
and
FIG. 3
, the thermal evolving apparatus for the PDP includes a heat evolution plate
33
opposed to the rear surface of the PDP, and a plurality of fans
37
installed at a rear case
36
of the PDP
30
. In the PDP
30
, discharge cells are provided between two sheets of glass substrates
10
and
18
. The heat evolution plate
33
is usually made from a metal having a high thermal conductivity, for example, aluminum. Thermal conductive sheets
32
and
34
are provided between the heat evolution plate and the PDP. The thermal conductive sheets
32
and
34
protect the rear surface of the PDP
30
and allow the heat evolution plate
33
of a metal material to be easily attached to the PDP
30
. A heat generated from the PDP
30
is conducted, via the thermal conductive sheets
32
and
34
, into the heat evolution plate
33
. The rear side of the heat evolution plate
33
is provided with a printed circuit board (PCB)
38
mounted with driving circuits. The PDP
30
, the heat evolution plate
33
and the PCB
38
are mounted within a space provided between a front case
35
and a rear case
36
. The fan
37
evolves a heat on the heat evolution plate
33
into the exterior to make a compulsory convection of a heat generated from the PDP with an external air.
Upon driving of the PDP
30
, the PDP
30
generates a high-temperatue heat by a gas discharge and a major portion of this heat is conducted into the heat evolution plate
33
. The heat on the heat evolution plate
33
conducted in this manner is subject to a compulsory convection with an external air by the heat evolution fan
37
. A portion of the heat is evolved via the front substrate
10
by a natural convection with an external air. In other words, the heat generated from the PDP
30
is evolved via two paths. One path I is a path in which a heat generated from the PDP
30
is removed through convection and radiation through the external air via the front substrate
10
by a conduction of the heat. Other path II is a path in which a heat generated from the PDP
30
is conducted, via the rear substrate
18
and the thermal conductive sheets
32
and
34
, into the thermal evolution plate
33
and thereafter makes a compulsory convection with an external air by the fan
37
. Since the former path I is at a front side of the PDP where a picture is displayed, it can not control a heat evolution. Accordingly, a heat evolution of the PDP
30
is mainly made via the latter path II. The heat evolution plate
33
and a plurality of fans
37
are installed at the latter path II to evolve a heat generated from the PDP
30
by a compulsory convection system.
However, the conventional thermal evolving apparatus for the PDP
30
has an even heat evolution effect, but fails to obtain a satisfying heat evolution efficiency. For this reason, in spite of an installation of the thermal evolving apparatus, a temperature of the PDP
30
has a high value of about 40 to 50° C. upon driving of the PDP
30
. If a temperature of the PDP
30
is kept at a high value, then the fluorescent material
22
and the electrodes
12
A,
12
B and
20
, etc. may be deteriorated and the PDP
30
is driven for a long time. Also, a clear picture can not be displayed and the PDP
30
may be damaged due to an overheating. Furthermore, the thermal evolving apparatus of the PDP
30
has a problem in that, since it must always drive the heat evolution fan
37
so as to make a heat evolution upon driving, a power consumption as well as a noise becomes large. Moreover, since the thermal evolving apparatus of the PDP
30
must assure a space for an installation of the heat evolution fan
37
, a thickness T of a PDP set becomes large as shown in FIG.
3
.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a thermal evolving method and apparatus for a plasma display
Kim Jeong Jun
Oh Jin Mok
Bell Bruce F.
Fleshner & Kim LLP
LG Electronics Inc.
Parsons Thomas H.
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