Electrophotography – Control of electrophotography process – Artificial intelligence
Reexamination Certificate
2000-04-20
2001-12-04
Sikes, William L. (Department: 2871)
Electrophotography
Control of electrophotography process
Artificial intelligence
C349S043000, C349S044000, C349S110000, C257S059000
Reexamination Certificate
active
06327443
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a monochrome or color liquid crystal display device which has been widely employed as a display device of a watch, a pocket calculator, a video camera, and a variety of electronic devices. Particularly, it relates to the structure of a liquid crystal display device having first and second electrodes which are disposed on one of two substrates between which a liquid crystal is filled, and also having an anode oxide film of the first electrode formed between the first and second electrodes as a nonlinear resistor layer, thereby forming a nonlinear resistor having a structure of “metal-insulating film-metal” or “metal-insulating film-transparent conductor” between the first and second electrodes.
BACKGROUND TECHNOLOGY
A display capacity of a liquid crystal display device using a liquid crystal display has been recently increased.
In a simple matrix structured liquid crystal display device employing a multiplex driving system, a contrast is dropped or a response speed is reduced as the speed of a time sharing is increased. Accordingly, if the liquid crystal display device has about 200 scanning lines, it is difficult to obtain a sufficient contrast.
Accordingly, there has been employed an active matrix system liquid crystal display panel having switching elements in each pixel to remove such drawbacks.
In the active matrix system liquid crystal display system, there are two types, one is a three terminal system employing thin film transistors (hereinafter referred to as “TFT”) as switching elements and the other is two terminal system employing nonlinear resistors. The two terminal system is superior to the three terminal system since the former is simple in structure and a method of manufacturing thereof.
A diode type, a varistor type, a thin film diode (hereinafter referred to as “TFD”) type and so on are developed as the two terminal system.
Among these types, the TFD type is simple in structure and has few manufacturing steps.
Further, the liquid crystal display panel is required to display with high density and high definition, and the switching elements require reduction of the area they occupy.
As a means for permitting the liquid crystal display panel to display with high density and high definition, a photo-lithography technique and an etching technique which are micro processing techniques in semiconductor production techniques are used. However, even if such semiconductor production techniques are employed, it is very difficult to realize a large area processing with low cost.
The structure of a conventional liquid crystal display device having a switching element which efficiently makes the area larger with low cost will be now described with reference to
FIG. 45
which is a plan view showing an example of a conventional liquid crystal display device,
FIG. 47
which is a plan view enlarging a part thereof and
FIG. 46
which is a cross sectional view taken along the line
47
—
47
in FIG.
45
.
The liquid crystal display device comprises, as shown in
FIG. 47
, a first substrate
1
, a second substrate
11
which are made of a transparent material and oppose each other by way of a spacer
17
at a certain gap, and a liquid crystal
16
which is filled between the first and second substrates
1
and
11
.
A lower electrode
2
and a signal electrode
4
are disposed on the first substrate
1
as a first electrode, and a nonlinear resistor layer
3
is provided on the lower electrode
2
. Further, an upper electrode
6
as a second electrode is provided on the nonlinear resistor layer
3
so as to overlap, thereby constituting a nonlinear resistor
9
. The upper electrode
6
as the second electrode extends from a display electrode
7
as shown in
FIG. 46
, and a part of the upper electrode
6
also serves as the display electrode
7
.
The nonlinear resistors
9
and the display electrodes
7
are disposed in a matrix shape.
A black matrix
12
is disposed on the second substrate
11
at a part confronting the first substrate
1
as shown by the hatched line in
FIG. 46
for preventing leaking of light from gaps defined in the display electrodes
7
disposed on the first substrate
1
. That is, the black matrix
12
is disposed on a non-display portion as a shading portion.
An opposed electrode
13
is disposed on the second substrate
11
in a belt shape by way of an interlayer insulating film
14
so as to oppose the display electrode
7
as shown in
FIG. 47
so that the opposed electrode
13
is not short circuited, without contact with the black matrix
12
.
In
FIG. 46
, the lower electrode
2
and the signal electrode
4
serving as the first electrode, and the upper electrode
6
and the display electrode
7
serving as the second electrode, disposed on the first substrate
1
, are shown by broken lines, wherein the illustration of the nonlinear resistor layer
3
is omitted, and the black matrix
12
and the opposed electrode
13
under the second substrate
11
are shown by solid lines.
The lower electrode
2
disposed on the first substrate
1
extends from the signal electrode
4
so as to constitute the nonlinear resistor
9
, and the lower electrode
2
serving as an overhanging region overlaps the upper electrode
6
to constitute the nonlinear resistor
9
.
The signal electrode
4
as the first electrode and the display electrode
7
as the second electrode are spaced at a certain gap d as shown in FIG.
46
.
The display electrode
7
is disposed to overlap the opposed electrode
13
by way of the liquid crystal
16
, thereby forming pixel portions of the liquid crystal display panel.
The black matrix
12
is provided to overlap a region forming the display electrode
7
to a given amount, thereby serving to prevent leaking of light from a peripheral region of the display electrode
7
.
The liquid crystal display device performs a given image display owing to the change of transmittance of the liquid crystal
16
in a region where the black matrix
12
is not provided on the display electrode
7
.
Further, orientational films
15
and
15
are provided between the first substrate
1
and the second substrate
11
at parts confronting the first substrate
1
and the second substrate
11
as processing layers for regularly aligning molecules of the liquid crystal
16
.
As shown in
FIG. 45
, the signal electrodes
4
in M rows are disposed on the first substrate
1
while the opposed electrodes
13
or data electrodes in N columns are disposed on the second substrate
11
so as to structure the liquid crystal display device having a display region
18
formed of a matrix in M rows and N columns as shown by one dot chain line.
The display electrodes
7
are provided at an intersection between the signal electrodes
4
in M rows and the opposed electrodes
13
or data electrodes in N columns, and the nonlinear resistors (TFD in this example)
9
are provided between the signal electrodes
4
and the display electrodes
7
.
An anode oxide electrode (anodizing electrode)
5
for connecting the signal electrode
4
in M rows with each other is disposed on the first substrate
1
, and connecting electrodes
8
for connecting the signal electrodes
4
with an external circuit are provided at a portion opposite to the anode oxide electrode
5
.
In such a manner, the signal electrodes
4
in each column are connected to each other by the anode oxide electrode
5
, and the lower electrodes
2
connected to the signal electrodes
4
are at once subject to an anodic oxidation treatment so as to form the nonlinear resistor
3
on the surface of the lower electrodes
2
(FIG.
47
), but the signal electrodes
4
in each column are separated from and independent of each other upon completion of the anodic oxidation treatment.
Accordingly, as shown in
FIG. 45
, the anode oxide electrode
5
has a cut portion
62
which extends outside of a separation line
34
(shown by a broken line) of the first substrate
1
by a length L, and the anode oxide electrode
5
is cut along the separation line
34
upon completion of the
Armstrong Westerman Hattori McLeland & Naughton LLP
Chowdhury Tarifur R.
Citizen Watch Co. Ltd.
Sikes William L.
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