Electric lamp and discharge devices: systems – Pulsating or a.c. supply – Induction-type discharge device load
Reexamination Certificate
2001-10-12
2004-12-14
Niebling, John F. (Department: 2812)
Electric lamp and discharge devices: systems
Pulsating or a.c. supply
Induction-type discharge device load
Reexamination Certificate
active
06831424
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, a light source device of a liquid crystal display device capable of minimizing leakage of power.
2. Description of the Related Art
As compared to Cathode Ray Tube (CRT) displays, liquid crystal display devices are lighter in weight, smaller in size, and provide full color and high resolution. As a result, many users prefer a liquid crystal display device over a CRT, for example, for use as a monitor of a computer or a household television that is hung on a wall, and the like.
Generally, when an electric field or an electric charge is applied to liquid crystal molecules, the liquid crystals become twisted, untwisted, or straightened in a predictable manner depending on the level of electric charge applied. The changing molecule pattern in the liquid crystals can be used to alter the optical characteristics of light passing through the crystals, such as blocking, passing, or partially passing the light. Therefore, the liquid crystal display device can display variations in images by controlling the liquid crystal cells.
FIG. 1
is an exploded perspective view showing a conventional liquid crystal display device and
FIG. 2
shows the constructions of a lamp adapted to a lamp unit shown in FIG.
1
.
Referring to
FIG. 1
, the liquid crystal display device
100
has a liquid crystal display module
130
for displaying an image when image signals are applied thereto and a front case
110
and a rear case
120
for receiving the liquid crystal display module
130
. The liquid crystal display module
130
includes a display unit
170
having a liquid crystal display panel
171
for displaying the image and a backlight assembly
150
for providing light to the display unit
170
.
The display unit
170
includes the liquid crystal display panel
171
, a data printed circuit board
176
, a gate printed circuit board
175
, a data tape carrier package
178
and a gate tape carrier package
174
.
The liquid crystal display panel
171
includes a thin film transistor substrate
172
and a color filter substrate
173
.
The thin film transistor substrate
172
is a transparent glass substrate on which thin film transistors are formed in a matrix. Data lines are connected to source terminals and gate lines are connected to gate terminals of the thin film transistors. Furthermore, pixel electrodes made of transparent and conductive material, such as Indium Tin Oxide (ITO), are connected to drain terminals of the thin film transistors.
The color filter substrate
173
, disposed against the thin film transistor substrate
172
, provides color to the image viewed. The color filter substrate
173
has red, green, and blue (RGB) pixels, typically formed by a thin film process, to present desired colors when light passes through the color filter substrate
173
. A surface of the color filter substrate
173
is covered with common electrodes made of ITO.
The thin film transistors of the thin film transistor substrate
172
correspond to the pixels of the display. They are selectively turned on and off to apply desired voltages to corresponding liquid crystals to change their orientations to pass or block the passage of light.
Control signals such as driving signals and timing signals are applied to the gate lines and data lines of the thin film transistors to control the amount of voltage applied at specified times to the liquid crystals in the liquid crystal display panel
171
to control the level of brightness affecting each pixel.
Image signals representing images to be displayed are received at the data printed circuit board
176
and the gate printed circuit board
175
, which apply driving signals to the data lines and the gate lines of the TFT substrate
172
in liquid crystal display panel
171
. The data printed circuit board
176
is connected to the data tape carrier package
178
for controlling the data line and the gate printed circuit board
175
is connected to the gate tape carrier package
174
for controlling the gate line in the liquid crystal display panel
171
. A source portion is formed on the data printed circuit board
176
to receive the image signals from an information process device such as a computer, etc. and then to provide a data driving signal to the data line of the liquid crystal display panel
171
. A gate portion is formed on the gate printed circuit board
175
to provide a gate driving signal for the gate line of the liquid crystal display panel
171
. That is, the data printed circuit board
176
and the gate printed circuit board
175
generate the gate driving signal and the data signal for driving the liquid crystal display device and the plural timing signals for applying the gate driving signal and the data signal at a proper time, so as to apply the gate driving signal through the gate tape carrier package
174
to the gate line of the liquid crystal display panel
171
and the data signal through the data tape carrier package
178
to the data line of the liquid crystal display panel
171
.
The backlight assembly
150
is disposed under the display unit
170
to supply light to the display unit
170
uniformly. The backlight assembly
150
includes lamp units
161
and
162
as light source. They are disposed at two ends of the liquid crystal display module
130
. A light guide plate
152
guides the light to the display unit
170
. A plurality of optical sheets
153
act to redirect and scatter evenly the light emitted from the light guide plate
152
. A reflective plate
154
disposed under the light guide plate
152
reflects the light leaked from the light guide plate
152
toward the display unit
170
.
The display unit
170
and the backlight assembly
150
are received in a mold frame
132
, which is provided with a top chassis
140
for preventing the display unit
170
from separating from the mold frame
132
.
Meanwhile, the liquid crystal display device has a bottom chassis
133
for shielding the display unit from electromagnetic waves. The bottom chassis
133
contains a printed circuit board (not shown, referred to as an inverter) including an inverter circuit to supply electricity to lamps of the lamp units
161
and
162
.
The front case
110
is combined with the rear case
120
so that the mold frame
132
is placed between the front case
110
and the rear case
120
, when the assembly of the liquid crystal display device is complete.
Referring to
FIG. 2
, the lamp units
161
and
162
respectively include a cold cathode tube
161
a
as a lamp, first and second power supply lines
163
and
164
for providing electric bias to the cold cathode tube
161
a
. Lamp holders
161
b
and
161
c
are used for positioning the cold cathode tube
161
a
. The first power supply line
163
applies a high voltage to the cold cathode tube
161
a
and the second power supply line
164
applies a low voltage to the cold cathode tube
161
a
. The first and second power lines
163
and
164
are connected to a connector
165
to receive an electric power source.
A plurality of lamps can be provided to each lamp unit of the liquid crystal display device, based on the size of the liquid crystal display device. If each of the lamp units
161
and
162
has two lamps, the number of power supply lines must be increased two times. That is, when there are two lamps disposed at each of two sides of the light guide plate
152
, the power supply lines extending from each of the lamp units
161
and
162
respectively have two high voltage power supply lines
163
and
163
a
and two low voltage power supply lines
164
and
164
a
, as shown in FIG.
3
.
The low voltage power supply lines and the high voltage power supply lines connected to both ends of each lamp are connected to a corresponding connector. The connector is connected with a connector of the inverter (not shown) mounted on a rear portion of the mold frame
132
to receive the power source. A shrinkable tube
167
wraps portions of the power supply lines
Lee Jeong-Hwan
Lee Seok-Won
Youn Sang-Hyuck
F. Chau & Associates LLC
Niebling John F.
Samsung Electronics Co. LTD
Stevenson Andre′
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