Electric lamp and discharge devices – With temperature modifier – Having heat conducting path
Reexamination Certificate
2002-10-30
2004-08-10
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With temperature modifier
Having heat conducting path
C313S47700R, C313S582000
Reexamination Certificate
active
06774544
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image display apparatus, and more particularly, to an image display apparatus comprising a temperature-equalizing device for equalizing a temperature of a panel. The present application is based on Korean Patent Application No. 2002-0002432, filed Jan. 16, 2002, which is incorporated in full by reference herein.
2. Description of the Prior Art
A plasma display panel (PDP) is a panel made of two base plates of glass which are fixed to each other in an air-tight manner. The PDP displays an image by utilizing a gas discharge phenomenon and requires a relatively simple fabrication process. Using a PDP, it is also easy to make a large and thin display screen. The PDP emits a large amount of heat during the operation due to the gas discharge phenomenon. Most of the PDPs have a radiating apparatus that uses a fan and is disposed at a rear end of the panel, for releasing the heat outwardly.
FIG. 1
is a cross sectional view showing an interior of a PDP having a conventional radiating apparatus.
Referring
FIG. 1
, a PDP
100
having a conventional radiating apparatus comprises a filter
110
, a panel
120
, a radiating plate
130
, a radiating fan
140
, a front casing
150
and a rear casing
160
. The filter
110
protects an image display apparatus such as the panel
120
from an external shock. The filter
110
mainly uses glass. The panel
120
consists of two base plates of glass formed typically with a gap of approximately 0.1 mm therebetween. The gap between the two base plates is under vacuum, and there occurs a gas discharge phenomenon in the gap. Accordingly, the PDP
100
displays an image by utilizing the gas discharge phenomenon that occurs in the vacuous gap.
On a rear surface of the panel
120
is provided the radiating plate
130
for equalizing a temperature of the panel
120
. The radiating plate
130
uses metallic plate of a high thermal conductivity such as aluminum. At a rear surface of the radiating plate
130
is provided at least one radiating fan
140
for cooling the panel
120
during the operation of the PDP
100
.
That is, when the PDP
100
is driven, heat is generated inside the panel
120
due to the gas discharge phenomenon. Most of the generated heat is conducted to the radiating plate
130
disposed at the rear surface of the panel
120
. The radiating fan
140
circulates inner air of the PDP
100
to cool the radiating plate
130
. When the PDP
100
does not include the radiating fan
140
, the radiating plate
130
is cooled by a natural convection caused by a temperature difference.
FIG. 1
shows the front casing
150
in a thick solid line and the rear casing
160
in a dotted line. The front casing
150
is disposed at a front surface of the PDP
100
where the filter
110
is disposed and the rear casing
160
is typically disposed at a rear surface of the PDP
100
where the radiating fan
140
is disposed, thereby protecting the PDP
100
from an external shock.
However, power that is consumed for driving the PDP
100
is converted to heat and discharged outwardly. The heat emitted from the PDP
100
heats the PDP
100
and ambient air of the PDP
100
, causing a convection phenomenon. A boundary layer is formed around the PDP
100
due to the convection phenomenon. The boundary layer typically needs to be made gradually thicker towards its upper end, and the upper end of the boundary layer has a higher temperature during operation of the PDP
100
than a lower end of the boundary layer. Another main reason that the upper end has a higher temperature than the lower end is that an exhaust operation is not smoothly performed due to the presence of the rear casing
160
.
FIG. 2
is an isothermal line showing a temperature distribution of the panel when the PDP is driven.
Referring to
FIG. 2
, the temperature distribution is irregular when the PDP
100
is driven and there is a great temperature difference between the upper end and the lower end. The temperature difference increases as the panel
120
is enlarged in size.
The temperature difference of the panel
120
shortens a life span of the PDP
100
, and the upper end and the lower end have different capacities such that an even quality of image cannot be obtained. With a larger size PDP
100
especially, the temperature difference between the upper end and the lower end of the panel
120
increases. Also, there is a limit on the ability to equalize the temperature of the panel
120
with the radiating plate
130
and the radiating fan
140
. Also, since the PDP
100
comprises the radiating fan
140
for cooling the PDP
100
, it is difficult to make the PDP
100
thinner. Additionally, power consumption is increased, and there is a problem of noise.
SUMMARY OF THE INVENTION
The present invention has been developed in order to solve the above problems in the prior art. Accordingly, an object of the present invention is to provide an image display apparatus comprising a temperature-equalizing device for equalizing a temperature of a panel.
The object is achieved by providing an image display apparatus comprising: an image display unit for displaying an image on a screen; and a radiating plate having a heat transmission unit for equalizing a surface temperature of the image display unit by circulating heat emitted from the image display unit.
More specifically, the heat transmission unit is a loop heat pipe, and the loop heat pipe has a small amount of operation fluid injected into an inside thereof, the inside of the loop heat pipe being under vacuum. The heat transmission unit is shaped in a closed loop and is disposed around an edge of the radiating plate. The heat transmission unit is shaped in a closed loop and is formed in a zigzag fashion.
According to the present invention, the image display apparatus is provided with the loop heat pipe, such that the temperature of the panel is equalized. Accordingly, the life span of the image display apparatus can be extended, and the equalized temperature of the panel can reduce a brightness difference that is caused by the temperature difference.
REFERENCES:
patent: 5132585 (1992-07-01), Kane et al.
patent: 5971566 (1999-10-01), Tani et al.
patent: 5990618 (1999-11-01), Morita et al.
patent: 6288489 (2001-09-01), Isohata et al.
Patel Ashok
Sughrue & Mion, PLLC
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