Liquid crystal cells – elements and systems – Particular structure – Particular illumination
Reexamination Certificate
2002-07-17
2004-01-06
Wong, Don (Department: 2821)
Liquid crystal cells, elements and systems
Particular structure
Particular illumination
C349S065000, C349S113000, C349S062000, C315S169300, C315S169400
Reexamination Certificate
active
06674496
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a transflective LCD device.
2. Description of the Prior Art
Due to low prices and high quality of LCD devices, the LCD device is widely applied in notebooks, PDA, mobile phones, and so on. Unlike cathode ray tubes (CRTs) and electro luminescence (EL) devices, LCD devices do not emit light beams, and accordingly they are equipped with supplemental light sources. In general, the LCD devices can be classified into reflective LCD devices, transmissive LCD devices, and transflective LCD devices. A reflective LCD device is illuminated by light beams that enter the device from the front of the device. A reflective surface (such as aluminum), placed inside the LCD device, returns light beams to illuminate the LCD device. Thus, the reflective LCD device can display images to a user in front of the LCD device. A transmissive LCD device usually has a backlight assembly disposed behind a liquid crystal layer. Light beams generated by the backlight assembly selectively penetrate the liquid crystal layer, and thus the transmissive LCD device can display images to a user in front of the LCD device. A transflective LCD device can display images both in a reflective mode and in a transmissive mode.
Please refer to FIG.
1
.
FIG. 1
is a schematic diagram of a prior art transflective LCD device. As shown in
FIG. 1
, a transflective LCD device
10
comprises an upper polarizer
12
, a retardation film
14
, an upper glass substrate
16
, a common counter electrode
18
, a liquid crystal layer
20
, a transparent electrode
22
, a lower glass substrate
24
, a light diffusing plate
26
, a reflective polarizer
28
, and a backlight assembly
30
. The backlight assembly
30
comprises a light source
30
a
, a light guide plate
30
b
, and a light absorbing plate
30
c
. One side of the backlight assembly
30
is opaque. The reflective polarizer
28
is made of a multi-layer dielectric film. Therefore, light beams are partially reflected by the reflective polarizer
28
and partially transmitted by the reflective polarizer
28
.
As shown in
FIG. 1
, ambient light beams partially enter the transflective LCD device
10
. As the ambient light beams penetrate each part of the transflective LCD device
10
, they are reflected by the reflective polarizer
28
. After that, the reflected ambient light beams penetrate each part of the transflective LCD device
10
. As a result, the transflective LCD device
10
can display images to a user
32
. The transflective LCD device
10
is operated in a reflective mode. In addition, as the ambient light beams are insufficient, the light source
30
a
of the backlight assembly
30
generates light beams to illuminate the transflective LCD device
10
. The light beams generated by the light source
30
a
partially penetrate the reflective polarizer
28
, and each part of the transflective LCD device
10
. Finally, the transflective LCD device
10
can display images to a user
32
. In this way, the transflective LCD device
10
is operated in a transmissive mode.
Through the use of the opaque backlight assembly
30
as a light source, the user
32
can see images through only one side of the transflective LCD device
10
. As the transflective LCD device
10
is utilized in a mobile phone with a folding section, each side of the folding section needs a piece of the transflective LCD device
10
so that the user can see images through opposite sides of the folding section. However, the folding section with two pieces of the transflective LCD device
10
will increase volume and weight of the mobile phone.
SUMMARY OF INVENTION
It is therefore a primary objective of the claimed invention to provide a transflective LCD device so that users can see images through opposite sides of the LCD device.
According to the claimed invention, a LCD device having a first side and a second side parallel with the first side is provided. The LCD device includes a front light source positioned on the first side of the LCD device for generating light beams, and a transflective liquid crystal panel. The transflective liquid crystal panel includes a first glass substrate located between the front light source and the second side of the LCD device, a second glass substrate located between the first glass substrate and the second side of LCD device, and a transflective layer located between the first glass substrate and the second glass substrate for reflecting and transmitting the light beams generated by the front light source. When the light beams generated by the front light source are reflected by the transflective layer and then are emitted to the first side of the LCD device, the LCD device displays images through the first side in a reflective mode, and when the light beams generated by the front light source are transmitted by the transflective layer and then are emitted to the second side of the LCD device, the LCD device displays images through the second side in a transmissive mode.
It is an advantage over the prior art that the claimed invention provides a transflective LCD device including a front light system and a transflective LCD panel. A user can see images through opposite sides of the transflective LCD device. As a result, in the claimed invention, only a single transflective LCD device is required to assemble electronic products capable of displaying images through opposite sides of the transflective LCD device, such as mobile phones. Thus, production cost is reduced, and further, volume and weight of the electronic products are also reduced.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the multiple figures and drawings.
REFERENCES:
patent: 2001/0017679 (2001-08-01), Ha et al.
patent: 2001/0050734 (2001-12-01), Cornelissen et al.
patent: 2003/0063243 (2003-04-01), Roosendaal et al.
Chi Mei Optoelectronics Corporation
Hsu Winston
Vo Tuyet T.
Wong Don
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