Liquid crystal cells – elements and systems – Particular structure – Holder – support – frame – or housing
Reexamination Certificate
2002-12-02
2004-11-02
Ton, Toan (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Holder, support, frame, or housing
C361S689000
Reexamination Certificate
active
06812976
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a display device. More particularly, the present invention relates to a liquid crystal display and method for fabricating same.
2. Description of the Related Art
The market of liquid crystal displays (LCDs) is growing wider and wider over various fields including office automation equipments, audio and visual equipments, and mobile equipments due to their advantage in thickness, weight and power consumption. As shown in
FIG. 23
, in assembly of a LCD, a housing front
49
and a housing rear
48
cooperate with each other to retain a backlight unit
33
, a panel unit
32
and a rear sheet metal
37
together in fixed operative relationship. The backlight unit
33
uses a front frame
35
and a rear frame
36
to retain lamp components, which include a lamp
11
, a reflector
12
, an optic sheet
16
, a reflector sheet
10
, and a light conductive plate
9
. The panel unit
32
uses a front bezel
34
to retain a liquid display panel (LCD)
1
. Connected to the LCD
1
are a connecting substrate
6
and a signal processing substrate
7
via a plurality of flexible substrates
4
. The flexible substrates include driver integrated circuits (ICs). The rear sheet metal
37
has mounted thereto a converter substrate
13
and an inverter substrate
14
. The converter substrate
13
is provided to convert external signal for transmission. The inverter substrate
14
is provided to supply a desired level of voltage to the lamp.
In the above-mentioned LCD, the lamp components are assembled to form one unit, the display components are assembled to form another unit and the signal processing circuit substrates are assembled to form other unit. Using the housing front
49
and housing rear
48
, these units are interconnected and retained in operative relationship. Using the units in assembly is closely related to varying of specification of a LCD with different user needs. Advantages of using the units include the following. Firstly, selecting units and interconnecting the selected units to meet different user needs may achieve a wide use of a LCD. Secondary, an ease and convenience of transport may be recognized if the components are manufactured at different sites function by function because the components are retained in operative relationship by frames.
The operative interconnection of the units may include not only electric connection, but also optic connection. Increased accuracy is required in alignment to provide performance as high as expected. Maintaining good display quality requires accurate alignment between the backlight and panel units
33
and
32
. It is the common practice to use frames to retain them together in operatively relationship.
One example of retaining a panel unit and a backlight unit is disclosed in JP-A 11-281963 (Toshiba). According to the teaching of this laid-open publication, the backlight unit includes a frame formed with first and second protrusions for alignment of a LCD panel of the panel unit. The first and second protrusions are arranged across the LCD panel for abutting engagement with the remote sides of it with clearance. A bezel is fast on sides of the frame of the backlight unit to retain the panel unit to the backlight unit in operative relationship. The bezel is formed with a bias protrusion that bulges into clearance between the second protrusion and the adjacent sides of the LCD panel, pressing it against the first protrusion.
Another example is disclosed in U.S. Pat. No. 5,905,550, Ohgami et al (=JP-A 9-297542, Toshiba). According to the teaching of this prior reference, a panel unit is formed with attachment flanges. With a bezel, the panel unit is fixed to a backlight unit to form an assembly. The assembly is mounted by interposing the attachment flanges between a housing front and a housing rear.
With reference to
FIGS. 24
to
33
, the first mentioned LCD will be further described.
FIGS. 24
to
33
are perspective views showing fabricating processes of the LCD.
FIGS. 24
to
27
show a sequence of processes for fabricating the backlight unit
33
.
FIGS. 28
to
30
show the subsequent fabricating processes till completion of the LCD.
Firstly, the assembly of a backlight unit
33
is described. As shown in
FIG. 24
, a reflector sheet
10
, a lamp
11
and a reflector
12
are inserted into a rear frame
36
. With a lamp retainer rubber
11
a
, the lamp
11
is temporarily fixed to the reflector
12
and has a lamp cable
15
. Subsequently, as shown in
FIG. 25
, a light conductive plate
9
, a diffusion film
16
b
and a lens film
16
a
are placed on the reflector sheet
10
within the rear frame
36
one after another. The diffusion and lens films
16
b
and
16
a
form an optic sheet
16
. Finally, as shown in
FIG. 26
, a front frame
35
cooperates with the rear frame
36
to interpose between them the backlight components, completing the assembly of the backlight unit (see FIG.
27
). Couplings
39
, each having a hook
36
a
on the rear frame
36
inserted into its mating hook hole
35
a
on the front frame
35
, and screws
38
fix the rear and front frames
36
and
35
to each other together.
Secondly, the assembly of a display unit
31
is described. As shown in
FIG. 28
, the backlight unit
33
is formed with a rib
40
for aligning a panel unit
32
, which includes an LCD panel
1
with flexible substrates
4
connected to connecting and signal processing substrates
6
and
7
. The LCD panel
1
is placed on the backlight unit
33
. Subsequently, as shown in
FIG. 29
, the flexible substrates
4
are bent down, admitting the connecting and signal processing substrates
6
and
7
into behind the backlight unit
33
. In one case, the connecting substrates
6
may be left on a forward surface of the backlight unit
33
. In another case, the connecting substrates
6
may be fixedly attached to sides of the backlight unit
33
. Subsequently, as shown in
FIG. 30
, a front bezel
34
and the backlight unit
33
interpose between them the panel unit
32
. Couplings
31
b
, each including a hook
35
b
on the sides of the front frame
35
inserted into its mating hook hole
34
a
, fix the front bezel
34
and the backlight unit
33
to each other together.
With reference to
FIGS. 31
to
33
, the subsequent fabrication processes are described. As shown in
FIG. 31
, the display unit
31
is turned up side down to face a display surface
32
a
down. Subsequently, a rear sheet metal
37
, which has mounted thereto inverter and converter substrates
14
and
13
by hooks
37
a
and screws
41
, is mounted onto the rear surface of the display unit
31
. Next, as shown in
FIG. 32
, screws
43
are used to fix the rear sheet metal
37
onto the rear surface of the backlight unit
33
. Connecting cables
42
interconnect the substrates. Lamp cables
15
are connected to the inverter substrate
14
. Finally, as shown in
FIG. 33
, with hooks
46
a
inserted into hook holes
46
b
and with screws
47
, a housing front
49
and a housing rear
48
are fixed to each other to embrace the display unit
31
.
The above-described LCD involves the following problems. One problem is the difficulty in further reducing the size, thickness and weight due to the use of front and rear frames
35
,
36
in forming the backlight unit
33
and the use of front bezel
34
in forming the display unit
31
. Another problem is the difficulty in maintaining precision required in final assembly of each product due to accumulation of alignment errors inevitably existing in the backlight and display units.
Another problem is the increased number of fabrication processes due to additional process of retaining or embracing assembled components of each unit and additional process of interconnecting the units.
Another problem is the complicated processes that require skilled labor. As mentioned before, the following processes form the display unit
31
. One process is to put the panel unit
32
onto the backlight unit
33
with its display surface
32
Choate Hall & Stewart
Duong Tai
NEC LCD Technologies Ltd.
Ton Toan
LandOfFree
Liquid crystal display and method for fabricating same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid crystal display and method for fabricating same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid crystal display and method for fabricating same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3355415