Liquid crystal cells – elements and systems – Particular excitation of liquid crystal – Electrical excitation of liquid crystal
Reexamination Certificate
2001-08-10
2003-12-23
Parker, Kenneth (Department: 2871)
Liquid crystal cells, elements and systems
Particular excitation of liquid crystal
Electrical excitation of liquid crystal
C349S043000, C349S152000, C349S187000
Reexamination Certificate
active
06667777
ABSTRACT:
The present application claims priority of Japanese Patent Application No.
2000-245211
filed on Aug. 11, 2000, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display device and a method for manufacturing the same.
2. Description of the Related Art
Conventionally, a liquid crystal display device equipped with a liquid crystal display panel has been applied to a wide range of display devices such as a TV monitor, a display apparatus for an OA (Office Automation) instrument, and a like.
The liquid crystal display panel is assembled by fixing a thin film transistor substrate (hereafter, may be referred to as a TFT substrate,) in which a thin film transistor (TFT) is formed, and an opposite substrate, in which a color filter is formed, in an opposite position through a space with some micrometers distance and a liquid crystal is sealed in this space.
FIG. 21
is a plan view showing a structure of one pixel of the TFT substrate of the conventional liquid crystal display panel,
FIG. 22
is a sectional view along with the P—P line of
FIG. 21
, and
FIG. 23
is the sectional view along with a P—P line of FIG.
21
.
In a TFT substrate
101
, as shown in
FIG. 21
, surrounding a transparent pixel electrode
102
arranged in a matrix pattern, each scanning line
103
to supply a scanning signal and each signal line
104
to supply a display signal are made to cross each other.
The TFT
101
a
(
FIG. 23
) is arranged around each crossing place of the scanning line
103
and the signal line
104
and used as a switching device, which applies a signal charge to a liquid crystal cell corresponding thereto by connecting a source electrode thereof to the transparent pixel electrode
102
. In the TFT
101
a
, a scanning signal is input to a gate electrode
105
, to which the scanning line
103
is connected, through the scanning line
103
, and actuation and control are operated by inputting a display signal (data signal) in a drain electrode
106
to which the signal line
104
is connected.
A liquid crystal capacitor (condenser) made by interposing liquid crystal between the transparent pixel electrode
102
of the TFT substrate
101
and an opposite electrode (common electrode) of an opposite substrate has a charge (even while the TFT
101
a
is turned OFF) corresponding to a signal to work the liquid crystal.
In order to reinforce electric charging performance of the liquid crystal capacitor and reduce an electric potential variability of the transparent pixel electrode
102
, an auxiliary capacitor is prepared in parallel to the liquid crystal capacitor. Namely, as shown in
FIG. 21
to
FIG. 23
, a auxiliary capacitor common electrode
108
, for example, is made, a auxiliary capacitor opposite electrode
109
is formed on a top part of the auxiliary capacitor common electrode
108
through a gate insulation film
110
, the auxiliary capacitor opposite electrode
109
is connected to the source electrode
107
through a connecting electrode
111
, and the auxiliary capacitor opposite electrode
109
is connected to the transparent pixel electrode
102
in a contact hole K
1
.
FIGS. 24A
to
24
F are process charts to explain a method for manufacturing this conventional liquid crystal display panel.
For preparation of the TFT substrate
101
, first, as shown in
FIG. 24A
, chromium film is formed on a transparent insulation substrate
112
and patterning is carried out to form the gate electrode
105
.
Subsequently, as shown in
FIG. 24B
, a silicon nitride film is formed on a whole surface, the gate insulation film
110
is formed, and the semiconductor layer
113
is formed by using amorphous silicon not doped and amorphous silicon made in a n
+
type by doping impurities.
Next, as shown in
FIG. 24C
, chromium film is formed on the surface of the semiconductor layer
113
and a near place thereof and patterning is carried out to form the source electrode
107
and the drain electrode
106
.
Next, as shown in
FIG. 24D
, the auxiliary capacitor opposite electrode
109
and the connecting electrode
111
are formed by using ITO (Indium Tin Oxide,) followed by, as shown in
FIG. 24E
, formation of the silicon nitride film and patterning is carried out to form a passivation film
114
.
Next, as shown in
FIG. 24F
, a transparent acryl polymer is patterned and an overcoat layer
115
is formed on the passivation film
114
.
Next, in the top of a central part of a pixel of the auxiliary capacitor common electrode
108
, the passivation film
114
and the overcoat layer
115
are etched to the contact hole K
1
(
FIG. 21
) and then, the ITO film is formed on the overcoat layer
115
to carry out patterning finally resulting in the transparent pixel electrode
102
.
A structure and method of the TFT substrate as described above (hereinafter, referred to as the first conventional art) have been disclosed in, for example, Japanese Patent No. 2933879.
FIG. 25
is a plan view for showing a structure of one pixel of a TFT substrate of another conventional liquid crystal display panel,
FIG. 26
is a sectional view along with a line R—R of
FIG. 25
, and
FIG. 27
is a sectional view along with a line S—S of FIG.
25
.
In the above described first conventional art, the auxiliary capacitor common electrode
108
is made and hence, an aperture ratio of the pixel reduces. On the other hand, the following art (hereafter, the second conventional art) has been proposed: the auxiliary capacitor common electrode
108
is not made and, as shown in
FIG. 25
to
FIG. 27
, a auxiliary capacitor opposite electrode
208
is made on top of a scanning line
203
of a preseding stage though a gate insulation film
210
, the gate insulation film
210
is interposed between scanning line
203
and auxiliary capacitor opposite electrode
208
to make a auxiliary capacitor for preparation of a TFT substrate
201
.
To a gate electrode
205
of a TFT
201
a
, the scanning line
203
is connected and to a drain electrode
206
, a signal line
204
is connected.
Where, a transparent pixel electrode
202
is connected to the auxiliary capacitor opposite electrode
208
in a contact hole K
2
and connected to a source electrode
207
in a contact hole K
3
.
FIGS. 28A
to
28
F are process charts showing places corresponding to those of
FIG. 26
, and
FIGS. 29A
to
29
F are process charts showing places corresponding to those of FIG.
27
.
For preparation of the TFT substrate
201
, first as shown in FIG.
29
A and
FIG. 28A
, a transparent insulation substrate
209
is prepared and, as shown in FIG.
29
B and
FIG. 28B
, a chromium film is formed on the transparent insulation substrate
209
and patterning is carried out to form the gate electrode
205
and the scanning line
203
.
Next, as shown in
FIGS. 29C and 28C
, the silicon nitride film is formed on the entire surface and patterning is carried out to form the gate insulation film
210
and as shown
FIG. 29C
, a semiconductor layer
211
is formed by using amorphous silicon not doped and amorphous silicon made to the n
+
type by doping.
Next, as shown in
FIGS. 29D and 28D
, the source electrode
207
and the drain electrode
206
are formed on the semiconductor layer
211
and also, the signal line
204
and the auxiliary capacitor opposite electrode
208
are formed.
Next, as shown in
FIG. 28E
, the silicon nitride is formed and patterning is carried out to form a passivation film
212
.
Next, as shown in FIG.
29
F and
FIG. 28F
, transparent acryl polymer is patterned and an overcoat layer
213
is formed on the passivation film
212
and then, in a point of connecting the transparent pixel electrode
202
to the source electrode
207
and in the point of connecting the transparent pixel electrode
202
to the auxiliary capacitor opposite electrode
208
, the passivation film
212
and the overcoat film
213
are etched, the contact holes K
2
and K
3
are formed, and the ITO film is formed on the overcoat film
213
and patterning is carried out to
Kikkawa Hironori
Maruyama Muneo
Okamoto Mamoru
Sakamoto Michiaki
Yamamoto Yuji
Duong Tai
Hayes & Soloway P.C.
NEC LCD Technologies Ltd.
Parker Kenneth
LandOfFree
Liquid crystal display device and method for manufacturing... 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 device and method for manufacturing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid crystal display device and method for manufacturing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3128895