Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2002-01-03
2004-08-24
Chowdhury, Tarifur R. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S062000, C349S063000, C362S035000
Reexamination Certificate
active
06781654
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display apparatus and a mobile terminal which display letter or image information and particularly, to a liquid crystal display apparatus and a mobile terminal having a liquid crystal panel which does not easily get out of order by an external impact.
2. Description of the Background Art
Generally, Liquid Crystal Display (LCD) is a displaying apparatus installed in a mobile terminal, monitor and the like and liquid crystal which is a material between liquid and solid condition is injected between two sheets of glass substrates formed as electrodes to display letters or images by adding an electric field.
As shown in
FIG. 1
, such liquid crystal display apparatus is installed in folder-type mobile terminal
1
and the like to display adjust or use condition or letter or image information, etc.
Particularly, since a liquid crystal panel composing the liquid crystal display apparatus can not emit light by itself, a back light sheet is installed at the rear side and accordingly letter or image information displayed on the liquid crystal panel can be recognized more clearly by penetrating light emitted from the back light sheet.
The back light sheet mainly employs a direct method for directly illuminating the front surface of the liquid crystal panel using Electro luminescence (EL) or an edge method for illuminating the liquid crystal panel using light diffused by a light transmission board having light sources at one or two sides of the liquid crystal panel. Between the methods, the liquid crystal display apparatus having a back light sheet by the direct method is mainly used for miniature electric devices such as mobile terminals and the like.
FIG. 2
is an exploded perspective view showing a conventional liquid crystal display apparatus by the direct method.
With reference to
FIG. 2
, the liquid crystal display apparatus
10
positioned in a mobile terminal is inserted-installed in a frame
17
fixed in a case of the terminal and as shown in
FIG. 1
, it displays letter or image information through a viewing window.
Since such liquid crystal display apparatus
10
has a liquid crystal panel
11
, a Flexible Printed circuit (FPC)
12
is connected to the liquid crystal panel
11
and a reflection board
13
for reflecting light incident from the liquid crystal panel
11
is adhered to the rear surface as a single body.
The back light sheet
15
formed as a flat board shape, for illuminating the liquid crystal panel
11
is positioned on the rear surface of the liquid crystal panel
11
where the reflection board
13
is attached. Here, the reflection board
13
penetrates the light emitted from the back light sheet
15
in the direction of the liquid crystal panel
11
.
Here, the reflection board
13
and back light sheet
15
forming the rear surface of the liquid crystal panel
11
are mutually attached by a double-faced adhesive tape
20
.
Therefore, the liquid crystal panel
11
, reflection board
13
and back light sheet
15
form a liquid crystal panel assembly and the liquid crystal panel assembly is inserted-assembled in the frame
17
.
Particularly, the double-faced adhesive tape
20
is formed in a square band shape not to interfere the light illuminated from the back light sheet
15
and maintain an adhesive force between the liquid crystal panel
11
and back light sheet
15
and is adhered to the circumferential portions
13
P and
15
P between the reflection board
13
and back light sheet
15
adhered to the liquid crystal panel
11
as a single body.
As shown in
FIG. 3
, the double-faced adhesive tape
20
is adhered to the inner surface
17
A of the frame
17
in
FIG. 2
having some portions
20
A and
20
B which are formed protruded further than the periphery of the back light sheet
15
.
On the other hand, as shown in
FIG. 2
, a polarizing plate
19
for forwardly penetrating the light penetrated through the liquid crystal panel
11
at the front side of the liquid crystal panel
11
.
However, since in the conventional liquid crystal display apparatus, the double-faced adhesive tape
20
is adhered to the circumferential surface of the liquid crystal panel
11
and back light sheet
15
, the liquid crystal panel
11
is easily transformed or broken by external impacts.
Namely, as shown in
FIG. 3
, since all parts of the liquid crystal panel
11
are adhered and bound to the back light sheet
15
by the double-faced adhesive tape
20
, when instantaneous impact is applied as in the case that the liquid crystal display apparatus falls and is collided with a bottom, the lower substrate
11
B of the liquid crystal panel
11
is adhered to the back light sheet
15
as a single body by the reflection board
13
and fixed to the frame
17
as shown in FIG.
4
. However, the upper substrate
11
A performs relative movement minutely contrary to the lower substrate
11
B by the falling impact and the upper substrate
11
A and the lower substrate
11
B are instantaneously cracked apart in the “A” and “B” directions.
When the upper substrate upper substrate
11
A and the lower substrate
11
B are instantaneously cracked apart, vacuum foams are formed from the liquid crystal
11
C filled between the both substrates
11
A and
11
B to the space cracked apart and a bleeding phenomenon of an exploded dotted pattern regardless of the inputted display signal. In the excessive case, letter or image information can not be clearly displayed by the bleeding phenomenon.
Particularly, in case of using a mobile communication instrument such as a mobile terminal, the bleeding phenomenon is often occurred when the instrument falls. At this time, as shown in
FIG. 5
, by the impact, the corner parts are damaged by the bleeding phenomenon and letter or image information is not displayed clearly.
Here,
FIG. 5A
shows the initial stage of the bleeding phenomenon that spots are occurred on the liquid crystal panel
11
right after the mobile terminal
1
falls in case the liquid crystal display apparatus
10
is installed in the mobile terminal
1
and
FIG. 5B
shows the bleeding expansion phenomenon that the spot (BL) is gradually expanded after 24 hours after the falling.
SUMMARY OF THE INVENTION
Therefore, to solve the above problem, the present invention provides a liquid crystal display apparatus and a mobile terminal capable of improving durability of the liquid crystal panel minimizing spot generation even though impacts by a falling or temperature change or a certain wrenching load is applied, by installing double-faced adhesive tape only at the edge portions except corner parts of the liquid crystal panel and the back light sheet and composing the liquid crystal panel and the back light sheet to be mutually adhered.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a liquid crystal display apparatus including a liquid crystal panel having a polygonal flat shape, a back light sheet positioned on the rear surface of the liquid crystal panel, for illuminating the liquid crystal panel with light and an adhesion member for mutually adhering the liquid crystal panel and the back light sheet by forming adhesion force in at least one part among edges except corner parts between the liquid crystal panel and the back light sheet.
Also, a mobile terminal for achieving the above object includes a transmission and reception means positioned at one side of a case, an input adjusting means exposed to external portion of the case being adjusted by a user, a control means for outputting a driving signal according to an input signal of the input adjusting means at the same time when the signals are inputted and outputted, being connected to the transmission and reception means, a liquid crystal display driving means operated by the output signal of the control means, a liquid crystal panel positioned in the case so that it can be shown from the outside, for displaying letter or image
An Soo Ho
Choi Seong Woo
Ha Young Sik
Kim Young Ho
Lee Sang Yong
Chowdhury Tarifur R.
Lee Hong Degerman Kang & Schmadeka
LG Electronics Inc.
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