U.S. patent application number 11/861991 was filed with the patent office on 2008-03-27 for in-plane switching type liquid crystal display device.
Invention is credited to Norihiro Arai, Kunpei Kobayashi, Toshiharu Nishino.
Application Number | 20080074602 11/861991 |
Document ID | / |
Family ID | 39224553 |
Filed Date | 2008-03-27 |
United States Patent
Application |
20080074602 |
Kind Code |
A1 |
Arai; Norihiro ; et
al. |
March 27, 2008 |
IN-PLANE SWITCHING TYPE LIQUID CRYSTAL DISPLAY DEVICE
Abstract
A liquid crystal display device comprises a pair of substrates
subjected to an aligning treatment in mutually parallel but
opposite directions, a liquid crystal layer interposed between the
pair of substrates, a first electrode bent into a "<" shape, and
a second electrode formed via an insulating film with the first
electrode. The first electrode comprises one linear section and
another linear section that extend in directions that intersect the
alignment treatment direction at different angles, a bent section
that is provided at each end where the one linear section and the
other linear section adjacent to each other and that extends in a
direction that intersects the alignment treatment direction at an
angle that is greater than each of the intersecting angles of the
one linear section and the other linear section and the alignment
treatment direction with respect to the alignment treatment
directions.
Inventors: |
Arai; Norihiro; (Tokyo,
JP) ; Kobayashi; Kunpei; (Tokyo, JP) ;
Nishino; Toshiharu; (Tokyo, JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN & CHICK, PC
220 Fifth Avenue, 16TH Floor
NEW YORK
NY
10001-7708
US
|
Family ID: |
39224553 |
Appl. No.: |
11/861991 |
Filed: |
September 26, 2007 |
Current U.S.
Class: |
349/146 |
Current CPC
Class: |
G02F 1/1337 20130101;
G02F 1/134363 20130101 |
Class at
Publication: |
349/146 |
International
Class: |
G02F 1/1343 20060101
G02F001/1343 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2006 |
JP |
2006-263223 |
Claims
1. A liquid crystal display device comprising: a pair of substrates
arranged opposite each other at a predetermined gap, having been
subjected to an aligning treatment in mutually parallel directions
on each of the mutually opposed inner surfaces; a liquid crystal
layer interposed in the gap between the pair of substrates and
arranged substantially in parallel with the surfaces of the
substrates, with the long axis of the liquid crystal molecule in
alignment with the direction of the aligning treatment; a plurality
of first electrodes provided on one of the mutually opposed inner
surfaces of the pair of substrates, comprising, in each
predetermined region for forming a single pixel, one linear section
and another linear section that extend in directions that intersect
the direction of the aligning treatment at different angles, a bent
section that is provided at each end where the one linear section
and the other linear section adjacent to each other, and that
extends in a direction that intersects the direction of the
aligning treatment at an angle greater than each of the
intersecting angles of the one linear section and the other linear
section and the aligning treatment direction with respect to the
aligning treatment direction, and a connection section that
connects these bent sections; and a second electrode that is
arranged in isolation from the first electrode on the inner surface
of the one substrate, and that generates with the first electrode a
transversal electric field that changes the orientation of the long
axis of the liquid crystal molecule within a plane substantially
parallel to the surfaces of the substrates.
2. The liquid crystal display device according to claim 1, wherein
the first electrode comprises a plurality of linear sections long
and narrow in shape which are formed in parallel at a distance from
each other, and at least either one of one and the other linear
sections in each pixel are connected to each other at least one of
ends thereof.
3. The liquid crystal display device according to claim 1, wherein
a plurality of slits for forming the plurality of linear sections
is formed on a transparent conductive film having an area
corresponding to a predetermined region for forming a single pixel,
and the first electrode is formed from a transparent conductive
film other than the transparent conductive film removed as a result
of the plurality of slits.
4. The liquid crystal display device according to claim 1, wherein
the first electrode forms two regions for aligning the orientation
of the long axes of the liquid crystal molecules in two different
orientations, a first orientation and a second orientation, when an
electric field is applied between the first electrode and the
second electrode, and one linear section of the first electrode is
formed in one of these two regions, and the other linear section of
the first electrode is formed in the other of the two regions.
5. The liquid crystal display device according to claim 1, wherein
the second electrode is arranged between the first electrode and
the one substrate.
6. The liquid crystal display device according to claim 1, wherein
a side border of a connection section of the first electrode is
formed into a continuous curved fringe.
7. The liquid crystal display device according to claim 1, wherein,
given an incline angle .theta.a of one linear section and another
linear section of the first electrode with respect to an aligning
treatment direction, and an incline angle .theta.b of the
respective bent sections provided at the ends of the two adjacent
linear sections with respect to the aligning treatment direction,
the incline angle .theta.a of the linear sections and the incline
angle .theta.b of the bent sections are set to:
0.degree.<.theta.a<20.degree.
20.degree.<.theta.b<40.degree.
8. The liquid crystal display device according to claim 1, wherein,
given a length La of one linear section and another linear section
of the first electrode, and a length Lb of the bent section, the
two lengths La and Lb are set so that: La>nLb (n: 3 to 5)
10Lb>La>4Lb.
9. The liquid crystal display device according to claim 1, wherein
the first electrode forms an end bent section that is provided on
at least the end of either one linear section or the other linear
section, connected to the linear section, on the side opposite the
side where the ends adjacent to each other, and that extends in a
direction that intersects the direction of the aligning treatment
at an angle greater than each of the intersecting angles of the one
linear section and the other linear section and the aligning
treatment direction with respect to the aligning treatment
direction.
10. The liquid crystal display device according to claim 9,
wherein, given an incline angle .theta.c of an end bent section
with respect to an aligning treatment direction, the incline angle
.theta.c is set to: 20.degree.<.theta.c<40.degree.
11. The liquid crystal display device according to claim 10
wherein, given a length La of the linear section and a length Lc of
the end bent section, the length Lc of the end bent section is set
to: La>nLc (n: 3 to 5) 10Lc>La>4Lc.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a liquid crystal display
device that controls the orientation of liquid crystal molecules
using a transversal electric field.
[0003] 2. Description of the Related Art
[0004] Known liquid crystal display devices include an In-plane
Switching (IPS) type liquid crystal display device that controls
the orientation of liquid crystal molecules using an electric field
parallel to the substrates that constitute the liquid crystal
display device.
[0005] This liquid crystal display device comprises a pair of
substrates arranged opposite each other at a predetermined gap,
having been subjected to an aligning treatment in mutually parallel
but opposite directions on each of the mutually opposed inner
surfaces and, in the gap therebetween, a liquid crystal layer
interposed substantially in parallel with the substrate surfaces,
with the long axes of the liquid crystal molecules aligned in the
direction of the aligning treatment. A pixel electrode in which a
plurality of bent electrodes long and narrow in shape is formed in
parallel at a distance from one another in a predetermined area for
forming a single pixel is provided on the inner surface of one of
the substrates of the pair of substrates, and an opposing electrode
for generating an electric field that changes the orientation of
the long axes of the liquid crystal molecules between the plurality
of electrodes of the pixel electrode to an orientation that is
substantially parallel to the substrate surfaces when voltage is
applied between the opposing electrode and the pixel electrode is
provided on the other substrate, in isolation from the pixel
electrode.
[0006] This In-plane Switching (IPS) type liquid crystal display
device generates an electric field parallel to the substrates that
corresponds to display data between the pixel electrode and the
opposing electrode. When an electric field is applied parallel to
the substrate, the In-plane Switching (IPS) type liquid crystal
display device controls on an inner surface substantially parallel
with the substrate surfaces the orientation of the long axes of the
liquid crystal molecules of a plurality of pixels comprising an
area corresponding to the pixel electrode and opposing electrode,
and displays an image.
[0007] Now, in the In-plane Switching (IPS) type liquid crystal
display device, as described in Unexamined Japanese Patent
Application KOKAI Publication No. 2002-182230, the plurality of
bent electrodes of the first electrode is formed into a shape bent
into a "<" shape to decrease the viewing angle dependability of
the display and achieve a display having a wide viewing angle. That
is, the orientation of the electric field parallel to the
substrates that is generated between the opposing electrode and one
of the electrodes of the two sections on either side of the bent
section of the "<" shape, and the orientation of the electric
field parallel to the substrates that is generated between the
other linear section and the second electrode are made to differ
from each other. With such an arrangement, the pixel electrode is
formed so that the liquid crystal molecules are arranged in two
different directions within each pixel.
[0008] However, in the In-plane Switching (IPS) type liquid crystal
display device in which the plurality of electrodes of the first
electrode are formed into a shape that is bent into a "<" shape,
the problem arises that, when a strong electric field parallel to
the substrates is generated, the orientation of the liquid crystal
molecules within each pixel becomes non-uniform and, as a result of
these pixels, display unevenness occurs.
SUMMARY OF THE INVENTION
[0009] The liquid crystal display device of the present invention
comprises:
[0010] a pair of substrates arranged opposite each other at a
predetermined gap, having been subjected to an aligning treatment
in mutually parallel directions on each of the mutually opposed
inner surfaces;
[0011] a liquid crystal layer interposed in the gap between the
pair of substrates and arranged substantially in parallel with the
surfaces of the substrates, with the long axis of the liquid
crystal molecule in alignment with the direction of the aligning
treatment;
[0012] a plurality of first electrodes provided on one of the
mutually opposed inner surfaces of the pair of substrates,
comprising one linear section and another linear section that
extend in directions that intersect the direction of the aligning
treatment at different angles in each predetermined region for
forming a single pixel, a bent section that is provided at each end
where the one linear section and the other linear section adjacent
to each other and that extends in a direction that intersects the
direction of the aligning treatment at an angle greater than each
of the intersecting angles of the one linear section and the other
linear section and the direction of the aligning treatment with
respect to the direction of the aligning treatment, and a
connection section that connects these bent sections;
[0013] and a second electrode that is arranged in isolation from
the first electrode on the inner surface of the one substrate, and
that generates with the first electrode an electric field parallel
to the substrates for changing the orientation of the long axes of
the liquid crystal molecules to within a plane that is
substantially parallel with the surfaces of the substrates.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a plan view that shows a section of one substrate
of a liquid crystal display device according to an example of the
present invention;
[0015] FIG. 2 is a cross-sectional view that shows a cross-section
of the liquid crystal display device shown in FIG. 1 cut along line
II-II;
[0016] FIG. 3 is an enlarged plan view showing an enlarged section
of the pixel electrode and opposing electrode of the liquid crystal
display device shown in FIG. 1;
[0017] FIG. 4 is an enlarged plan view shown an enlarged one bent
electrode of the pixel electrode of the liquid crystal display
device shown in FIG. 1;
[0018] FIG. 5 is an enlarged cross-sectional view showing an
enlarged cross-section of the liquid crystal display device shown
in FIG. 1 cut along line V-V of FIG. 3;
[0019] FIG. 6 is a plan view showing the orientation of the liquid
crystal molecules of each section within one pixel when an electric
field parallel to the substrates is generated between the pixel
electrode and opposing electrode;
[0020] FIG. 7 is an enlarged cross-sectional view showing an
enlarged cross-section of the liquid crystal display device shown
in FIG. 1 cut along line VII-VII of FIG. 6;
[0021] FIG. 8 is an enlarged cross-sectional view showing an
enlarged cross-section of the liquid crystal display device shown
in FIG. 1 cut along line VIII-VIII of FIG. 6;
[0022] FIG. 9 is a plan view that shows a comparison example where
a plurality of bent electrodes of the pixel electrode are formed
into a "<" shape where two electrode sections directly connect,
and shows the orientation of the liquid crystal molecules of each
section within one pixel when an electric field parallel to the
substrates is generated between the pixel electrode and opposing
electrode;
[0023] FIG. 10 is an enlarged cross-sectional view showing an
enlarged cross-section of the liquid crystal display device shown
in FIG. 9 cut along line X-X of FIG. 9;
[0024] FIG. 11 is an enlarged cross-sectional view showing an
enlarged cross-section of the comparison example shown in FIG. 9
cut along line XI-XI of FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] FIG. 1 to FIG. 8 illustrate an example of the present
invention. FIG. 1 is a plan view showing a section of one substrate
of a liquid crystal display device, and FIG. 2 is a cross-sectional
view showing a cross-section of the liquid crystal display device
shown in FIG. 1 cut along line II-II.
[0026] This liquid crystal display device, as shown in FIG. 1 and
FIG. 2, comprises a pair of transparent substrates 1 and 2 arranged
opposite each other at a predetermined gap on an observed side
(upper side in FIG. 2) and a side opposite that side, and a liquid
crystal layer 3 interposed in the gap between the pair of
substrates 1 and 2. First and second transparent electrodes 4 and 5
for generating an electric field that is substantially parallel to
the surfaces of the substrates 1 and 2 when voltage is applied are
formed in isolation from each other on one of the two mutually
opposed inner surfaces of the pair of substrates 1 and 2, such as
on the inner surface of the substrate 2 of the side opposite the
observed side, for example. One of the plurality of first
transparent electrodes 4 and the second transparent electrode 5 are
arranged opposite each other, and a single pixel 100 that controls
the orientation of the long axes of the liquid crystal molecules of
the liquid crystal layer 3 is defined by the area where the
electric field parallel to the substrates is generated between
these electrodes. These pixels are arranged in plurality in a
matrix shape. A pair of polarizing plates 19 and 20 of the observed
side and the side opposite the observed side are disposed on the
outer surface of the pair of substrates 1 and 2.
[0027] Hereinafter, the substrate 1 of the observed side is
referred to as the "front substrate," the substrate 2 on the side
opposite the observed side is referred to as the "back substrate,"
the polarizing plate 19 of the observed side arranged on the outer
surface of the front substrate 1 is referred to as the "front side
polarizing plate," and the polarizing plate 20 of the opposite side
arranged on the outer surface of the back substrate 2 is referred
to as the "back side polarizing plate."
[0028] The pair of substrates 1 and 2 are joined via a frame-shaped
sealing material (not shown), and the liquid crystal layer 3 is
interposed in the area of the gap between the pair of substrates 1
and 2 that is enclosed by the sealing material.
[0029] This liquid crystal display device is an active matrix
display device. Of the first and second electrodes 44 provided in
isolation from each other on the inner surface of the back
substrate 2, a first electrode 4 is a plurality of pixel electrodes
arranged in a matrix shape in a row direction (horizontally on the
screen) and a column direction (vertically on the screen). A second
electrode 5 is an opposing electrode arranged on a per row basis
correspondingly to each pixel electrode 4 of that row.
[0030] Then, a plurality of active elements 6 arranged
correspondingly to the plurality of pixels 100, a plurality of scan
lines 12 arranged per pixel row comprising the plurality of pixels
100 arranged in the row direction, and a plurality of signal lines
13 arranged per pixel row comprising the plurality of pixels 100
arranged in the row direction are provided on the inner surface of
the back substrate 2.
[0031] The active element 6 comprises an input electrode 10 and a
output electrode 11 of a signal, and a control electrode 7 that
controls the conduction between the input electrode 10 and the
output electrode 11. The control electrode 7 is connected to the
scan line 12 at each row, the input electrode 10 is connected to
the signal line 13 at each column, and the output electrode 11 is
connected to the pixel electrode 4.
[0032] The active element 6 is, for example, a TFT (thin film
transistor), and comprises a control electrode (gate electrode) 7
formed on the surface of the back substrate 2, a transparent gate
insulating film 8 formed on roughly the entire surface of the back
substrate 2 covering the control electrode 7, an i-type
semiconductor film 9 formed opposite the control electrode 7 on the
gate insulating film 8, and a input electrode (drain electrode) 10
and output electrode (source electrode) 11 provided via an n-type
semiconductor film (not shown) on both side sections of the i-type
semiconductor film 9 hereinafter, the active elements 6 is referred
to as "TFT".
[0033] Each of the plurality of scan lines 12 is formed on the
surface of the back substrate 2 along one side (the bottom side in
FIG. 1) of each pixel row in parallel with the pixel row,
respectively connected to the gate electrode 7 of the TFT 6 of each
row. Each of the plurality of signal lines 13 is formed along one
side (the left side of FIG. 1) of each pixel column in parallel
with the pixel column above the gate insulating film 8,
respectively connected to the drain electrode 10 of the TFT 6 of
each column.
[0034] The terminal alignment section (not shown) extending toward
the outside of the front substrate 1 is formed on the border of the
back substrate 2, and the plurality of scan lines 12 and the
plurality of signal lines 13 are connected to a plurality of scan
line terminals and signal line terminals provided on the terminal
alignment section.
[0035] Then, the plurality of pixel electrodes 4 is formed above a
transparent interlayer insulating film 14 formed on the front
surface (not shown) of the back substrate 2, covering the plurality
of TFT 6 and signal lines 13, and the opposing electrode 5 is
formed above the gate insulating film 8. That is, the opposing
electrode 5 is positioned farther toward the back substrate 2 side
than the plurality of pixel electrodes 4, in isolation from the
plurality of pixel electrodes 4 by the interlayer insulating film
14.
[0036] Each of the plurality of pixel electrodes 4 is formed in,
for example, each region of a vertically long rectangular shape
having a greater height along the vertical direction than the width
along the horizontal direction of the screen, in a predetermined
region for forming a single pixel 100, and comprises a first
transparent conductive film (ITO film, for example) 40 that is
formed in parallel with and at a distance from a plurality of bent
electrodes 41 long and narrow in shape, having a length extending
across roughly the entire length in the height direction of the
region.
[0037] The plurality of bent electrodes 41 of the pixel electrode 4
is formed by providing a plurality of slits in the first conductive
film 40. Then, these bent electrodes 41 are connected to common
connection sections 45a and 45b formed on both end borders of the
first conductive film 40, at the respective ends.
[0038] Then, one end side of the common connection section 45b of
one end border (bottom end border of FIG. 1) of the first
conductive film 40 overlaps the source electrode 11 of the TFT 6
via the interlayer insulating film 14. This first conductive film
40 is connected to the source electrode 11 in a connecting hole
(not shown) provided on the interlayer insulating film 14.
[0039] The opposing electrode 5 is provided on a per pixel row
basis across the total length thereof, and comprises a second
transparent electrode film (for example, ITO film) 50 formed into a
shape corresponding to the entire area of the plurality of pixels
100 of each row.
[0040] The second conductive film 50, as shown in FIG. 1, is
patterned, forming a vertically long, rectangular opposing section
51 corresponding to the pixel shape in each area respectively
corresponding to the plurality of pixels 100 of each row. Then,
these opposing sections 51 are formed into a shape connected by the
common connection section 52 of the side (the top end of the pixel
100 in the figure) opposite the side where the scan line 12 is
established.
[0041] The second conductive film 50 may also be formed to a width
corresponding to the height of the pixel 100, covering the entire
length of the pixel row. With this arrangement, the second
conductive film 50 is formed across the top of the plurality of
signal lines 13, and the intersecting section of the second
conductive film 50 and the signal line 13 is insulated by an
insulating film (not shown) covering the signal line 13.
[0042] Then, the plurality of second conductive films 50
respectively corresponding to each pixel row is commonly connected
(not shown) on the outside of the display region where the
plurality of pixel electrodes 4 is arranged. Further, the common
connection section of the second conductive film 50 is connected to
an opposing electrode terminal provided on the terminal alignment
section of the back substrate 2.
[0043] The opposing electrode 5 comprising the second conductive
film 50 generates an electric field parallel to the substrates that
changes the orientation of the long axis of the liquid crystal
molecule 3 a to an orientation substantially parallel with the
surfaces of the substrates 1 and 2, between the plurality of bent
electrodes 41 of the pixel electrode 4 when voltage is applied
between the opposing electrode 5 and the pixel electrode 4.
[0044] On the other hand, a light shielding film 15 corresponding
to the plurality of TFT 6 and the areas between the plurality of
pixels 100 is formed on the inner surface of the front substrate 1.
Color filters 16R, 16G, and 16B of the three colors red, blue, and
green are provided correspondingly to the respective plurality of
pixels 100, on the light shielding film 15.
[0045] Furthermore, horizontal alignment films 17 and 18 of a
polyimide film, etc., that align the liquid crystal molecule 3a of
the liquid crystal layer 3 so that its long axis is substantially
parallel with the surfaces of the substrates 1 and 2, are formed on
the inner surface of the front substrate 1, respectively covering
the color filters 16R, 16G, and 16B provided on the front substrate
1 and the plurality of pixel electrodes 4 provided on the back
substrate 2.
[0046] Then, the inner surfaces of the pair of substrates 1 and 2
are each subjected to an aligning treatment in mutually parallel
but opposite directions by rubbing the film surfaces of the
alignment films 17 and 18, respectively, in predetermined
directions.
[0047] FIG. 3 is an enlarged plan view showing an enlarged section
of the pixel electrode 4 and the opposing electrode 5, and FIG. 4
is an enlarged plan view showing an enlarged bent electrode 41 of
the pixel electrode 4.
[0048] In FIG. 1, FIG. 3, and FIG. 4, 1a indicates the aligning
treatment direction of the inner surface of the front substrate 1
(rubbing direction of the horizontal alignment film 17), and 2a
indicates the aligning treatment direction of the inner surface of
the back substrate 2 (rubbing direction of the horizontal alignment
film 18), respectively. In this example, the vertical alignment
film 17 of the inner surface of the front substrate 1 is aligned,
via the aligning treatment, parallel to the vertical direction of
the screen, from the bottom to the top of the screen, and the
vertical alignment film 18 of the inner surface of the back
substrate 2 is aligned, via the aligning treatment, parallel to the
vertical direction of the screen, from the top to the bottom of the
screen.
[0049] Then, each of the plurality of bent electrodes 41 of the
pixel electrode 4 is formed so that two linear sections 42a and 42b
intersect the aligning treatment directions 1a and 2a,
respectively, at different angles, as shown in FIG. 3 and FIG. 4.
Further, at the center of the unit region of the rectangular shape
in the vertical direction, the plurality of bent electrodes 41 are
formed so that they substantially bend into a "<" shape
connected at the section where the two linear sections 42a and 42b
intersect. Then, in the section where the two linear sections 42a
and 42b connect, a bent section 43a wherein the side connected to
one linear section 42a bends in a direction in which the incline
angle with respect to the aligning treatment directions 1a and 2a
increases with respect to the one linear section 42a, and a bent
section 43b wherein the side connected to the other linear section
bends in a direction in which the incline angle with respect to the
aligning treatment directions 1a and 2a increases with respect to
the other linear section 42b are provided. The connection section
that connects the bent sections 43a and 43b, which connect the two
linear sections 42a and 42b, is formed in a circular arc shape
where one side border and the other side border smoothly
connect.
[0050] That is, the bent electrode 41 is formed from the two linear
sections 42a and 42b having first inclines that differ in incline
orientation with respect to the aligning treatment directions 1a
and 2a, and the bent sections 43a and 43b having second inclines
with incline angles that are greater than the first incline and
differ in incline orientation with respect to the aligning
treatment directions 1a and 2a. Further, the bent electrode 41 is
continually formed with the connection section where these bent
sections 43a and 43b connect to each other.
[0051] The two linear sections 42a and 42b of the bent electrode 41
are formed at substantially the same width. The ratio of a distance
D.sub.1 between the neighboring one linear sections 42a and 42a of
the bent electrode 41 to a width W.sub.1 of the one linear section
42a is set to D.sub.1/W.sub.1, and the ratio of a distance D.sub.2
between the neighboring one linear sections 42b and 42b of the bent
electrode 41 to a width W.sub.2 of the other linear section 42b is
set to D.sub.2/W.sub.2, with each set to 1/3 to 3/1, preferably to
1/1.
[0052] Further, given an incline angle .theta.a of the two linear
sections 42a and 42b of the plurality of bent electrodes 41 of the
pixel electrode 4 with respect to the aligning treatment directions
1a and 2a, and an incline angle .theta.b of the two bent sections
43a and 43b connecting the two linear sections 42a and 42b with
respect to the aligning treatment directions 1a and 2a, .theta.a
and .theta.b are set to:
0.degree.<.theta.a<20.degree.
20.degree.<.theta.b<40.degree.
[0053] Furthermore, given a length La of the two linear sections
42a and 42b, and a length Lb of the two bent sections 43a and 43b
connecting the two linear sections 42a and 42b, the lengths La and
Lb are set so that:
La>nLb (n: 3 to 5)
10Lb>La>4Lb.
[0054] Further, end bent sections 44a and 44b respectively
connected to the linear sections 42a and 42b and bent in a
direction where the incline angles with respect to the aligning
treatment directions 1a and 2a increase with respect to the linear
sections 42a and 42b are respectively formed at the ends of the
side opposite the end where the two linear sections 42a and 42b of
the plurality of bent electrodes 41 of the pixel electrode 4
adjacent to each other. Then, the connecting sections of these end
bent sections 44a and 44b and the linear sections 42a and 42b are
each formed into a circular arc where one side border and the other
side border smoothly connect.
[0055] Given an incline angle .theta.c of the end bent sections 44a
and 44b respectively formed at the ends of the two linear sections
42a and 42b with respect to the aligning treatment directions 1a
and 2a, .theta.c is set to:
20.degree.<.theta.c<40.degree.
[0056] Then, given a length Lc of the end bent sections 44a and
44b, the length Lc with respect to the length La of the linear
sections 42a and 42b of the bent electrode section 41 is set to a
value such that:
La<nLc (n: 3 to 5)
10Lc>La>4Lc.
[0057] That is, the end bent sections 44a and 44b of both ends of
the bent electrode 41 are formed at substantially the same incline
angle and length as the bent sections 43a and 43b connecting the
two linear sections 42a and 42b.
[0058] The incline angle .theta.a of the two linear sections 42a
and 42b of the plurality of bent electrodes 41 of the pixel
electrode 4 with respect to the aligning treatment directions 1a
and 2a is preferably set to
5.hoarfrost..about.15.hoarfrost.(10.degree..+-.5.degree.), more
preferably to 8.hoarfrost..hoarfrost.12.hoarfrost.
(10.degree..+-.2.degree.) Further, the incline angles .theta.b and
.theta.c of the bent sections 43a and 43b connecting the two linear
sections 42a and 42b and the end bent sections 44a and 44b with
respect to the aligning treatment directions 1a and 2a are
preferably set to 25.quadrature..about.35.quadrature.
(30.degree..+-.5.degree.), more preferably to
30.degree..+-.2.degree..
[0059] Of the plurality of bent electrodes 41 of the pixel
electrode 4, the linear section 42b of the side connected to the
TFT 6 is formed to a length this is shorter than the linear section
42b of the other bent electrode 41, away from the region
corresponding to a source electrode 11 of the TFT 6.
[0060] The liquid crystal layer 3 comprises nematic liquid crystal
having positive dielectric anisotropy and, in the initial state
when an electric field is not generated between the pixel electrode
4 and the opposing electrode 5, the liquid crystal molecule 3a of
this liquid crystal layer 3 is aligned substantially parallel with
the surfaces of the substrates 1 and 2, with its long axis in the
aligning treatment directions 1a and 2a.
[0061] FIG. 5 shows an enlarged view of a cross-section cut along
line V-V of FIG. 3. The liquid crystal molecule 3a, as shown in
FIG. 3 and FIG. 5, is aligned with its long axis in alignment with
the aligning treatment directions 1a and 2a. The liquid crystal
molecule 3a is aligned with the liquid crystal molecule end that is
on the side toward the aligning treatment directions 1a and 2a
formed on the respective inner surface of each substrate pretilted
away from the respective substrate. That is, the liquid crystal
molecule 3a is aligned substantially parallel to the surfaces of
the substrates 1 and 2.
[0062] Further, a transparent anti-static conductive film 21 of a
single film shape for blocking static electricity from outside is
provided between the front substrate 1 and a front side polarizing
plate 19 arranged on the outer surface thereof, across the entire
surface of the front substrate 1.
[0063] This liquid crystal display device generates an electric
field parallel to the substrates that changes the orientation of
the long axis of the liquid crystal molecule 3 a between the
plurality bent electrodes 41 of the pixel electrode 4 and the
opposing electrode 5 to substantially parallel with the surfaces of
the substrate 1 and 2 by applying drive voltage corresponding to
display data between the pixel electrode 4 and the opposing
electrode 5 of the plurality of pixels 100. Then, the liquid
crystal display device controls on a surface substantially parallel
with the surfaces of the substrates 1 and 2 the orientation of the
long axis of the liquid crystal molecule 3a of the plurality of
pixels 100 by this electric field parallel to the substrates, and
displays an image.
[0064] The drive voltage applied between the pixel electrode 4 and
the opposing electrode 5 is controlled within the range of a
minimum value of substantially 0 at which the electric field
parallel to the substrates is not generated, to a maximum value at
which an electric field parallel to the substrates is generated at
an intensity that aligns the liquid crystal molecule 3a of the
pixel region where the pixel electrode 4 is arranged so that its
long axis is substantially in the direction of 45.degree. with
respect to the aligning treatment directions 1a and 2a.
[0065] The liquid crystal display device of this example is, for
example, a non-electrolytic black display type (hereinafter
"normally black type") in which the transparent axis of either the
front side polarizing plate 19 or the back side polarizing plate 20
is substantially parallel with or substantially orthogonal to the
aligning treatment directions 1a and 2a, and the transparent axis
of the other polarizing plate is substantially orthogonal to the
one polarizing plate. Then, the display of the pixel 100 turns
black in non-electrolytic mode in which an electric field parallel
to the substrates is not generated between the pixel electrode 4
and the opposing electrode 5, that is, when the liquid crystal
molecule 3a is aligned so that its long axis is in alignment with
the aligning treatment directions 1a and 2a, as shown in FIG. 3.
Further the display of the pixel 100 becomes brightest when an
electric field parallel to the substrates of an intensity that
aligns the liquid crystal molecule 3a so that its long axis is
substantially in the direction of 45.degree. with respect to the
aligning treatment directions 1a and 2a is generated between the
pixel electrode 4 and the opposing electrode
[0066] FIG. 6 shows the orientation of the long axis of the liquid
crystal molecule 3a of each section in a single pixel 100 when an
electric field parallel to the substrates of an intensity that
aligns the liquid crystal molecule 3a so that its long axis is
substantially in the direction of 45.degree. with respect to the
aligning treatment directions 1a and 2a is generated between the
pixel electrode 4 and the opposing electrode 5. FIG. 7 shows an
enlarged view of a cross-section cut along line VII-VII of FIG. 6.
FIG. 8 shows an enlarged view of a cross-section cut along line
VIII-VIII of FIG. 6.
[0067] As shown in FIG. 6 and FIG. 8, a transversal electric field
E is generated between the section adjacent to the bent electrode
41 of the opposing electrode 5 and one side border (fringe) and the
other side border of the plurality of bent electrodes 41 of the
pixel electrode 4.
[0068] This transversal electric field E is an electric field of a
direction orthogonal to the side border of the plurality of bent
electrodes 41 of the pixel electrode 4. The orientation of the
liquid crystal molecule 3a is changed by the generation of the
transversal electric field E to a direction in which the angle of
its long axis with respect to the orientation of the transversal
electric field E decreases.
[0069] Then, this liquid crystal display device is formed into a
shape in which the plurality of bent electrodes 41 of the pixel
electrode 4 is substantially bent into a "<" shape, and the two
linear sections 42a and 42b respectively intersect the aligning
treatment directions 1a and 2a of the inner surfaces of the pair of
substrates 1 and 2 at substantially the same angle. As a result,
the liquid crystal display device, as shown in FIG. 6, can set
different orientations for the transversal electric field E
generated between one linear section 42a of the plurality of bent
electrodes 41 of the pixel electrode 4 and the opposing electrode
5, and the transversal electric field E generated between the other
linear section 42b of the bent electrode 41 and the opposing
electrode 5. This enables formation of a region where the liquid
crystal molecule 3a is aligned in two different orientations within
each pixel 100, thereby achieving a display having a wide view
without display view dependability.
[0070] Additionally, this liquid crystal display device provides in
the section connecting the two linear sections 42a and 42b of the
plurality of bent electrodes 41 of the pixel electrode 4 a bent
section 43a wherein the side connected to one linear section 42a
bends in a direction in which the incline angle with respect to the
aligning treatment directions 1a and 2a increases with respect to
the one linear section 42a, and a bent section 43b wherein the side
connected to the other linear section 42b bends in a direction in
which the incline angle with respect to the aligning treatment
directions 1a and 2a increases with respect to the other linear
section 42b, and is formed into a shape in which these bent
sections 43a and 43b connect at a connection section. As a result,
even when a strong transversal electric field E that aligns the
liquid crystal molecule 3a so that its long axis is substantially
at or near the direction of 45.degree. with respect to the aligning
treatment directions 1a and 2a is generated between the pixel
electrode 4 and the opposing electrode 5, the liquid crystal
molecule 3a never tilts at an incline opposite the incline of the
pretilt resulting from the aligning treatment.
[0071] That is, as shown in the comparative example of FIG. 9, with
an electrode of a "<" shape, the transversal electric field E
generated between one side border of the bent electrode 41 of the
pixel electrode 4 and the opposing electrode 5 and the transversal
electric field E generated between the other side border of the
other linear section 42b of the bent electrode 41 and the opposing
electrode 5 have mutually opposite orientations. Then, the
plurality of bent electrodes 41 of the pixel electrode 4 is formed
into a shape that bends substantially into a "<" shape with the
two linear sections 42a and 42b respectively intersecting at
opposite incline angles with respect to the aligning treatment
directions 1a and 2a.
[0072] The transversal electric field E generated between one side
border of one linear section 42a of the bent electrode 41 of the
pixel electrode 4 and the opposing electrode 5, and the transversal
electric field E generated between the other side border of the
other linear section 42b of the bent electrode 41 and the opposing
electrode 5 are each an electric field of an orientation that tilts
the liquid crystal molecule 3a, which had changed orientation due
to the transversal electric field E, to an incline opposite the
incline of the pretilt resulting from the aligning treatment of the
substrate inner surfaces (hereinafter opposite electric field).
[0073] With this arrangement, when a strong transversal electric
field E is generated between the pixel electrode 4 and the opposing
electrode 5, the force that tilts the liquid crystal molecule 3a as
a result of the transversal electric field E acting on the liquid
crystal molecule 3a becomes stronger that the force (tilt
orientation force of aligning films 17 and 18) that pretilts the
liquid crystal molecule 3a as a result of the aligning treatment of
the substrate inner surfaces. In consequence, the liquid crystal
molecule 3a of the opposite electric field generation region S1
along one side border of one linear section 42a of the bent
electrode 41, and the liquid crystal molecule 3a of the opposite
electric field generation region S2 along the other side border of
the other linear section 42b tilt at an incline opposite the
incline of the pretilt resulting from the aligning treatment of the
substrate inner surfaces.
[0074] That is, when the transversal electric field E is a weak
electric field that changes the long axis orientation of the liquid
crystal molecule 3a at a small angle with respect to the aligning
treatment directions 1a and 2a, the liquid crystal molecule 3a
changes in orientation when tilted in the incline direction of the
pretilt resulting from the aligning treatment of the substrate
inner surfaces, even in the opposite electric field generation
area, due to the pretilt orientation force of the substrate inner
surfaces. However, when the transversal electric field E is a
strong electric field that changes the orientation of the long axis
of the liquid crystal molecule 3a at a large angle with respect to
the aligning treatment directions 1a and 2a, the force resulting
from the electric field parallel to the substrates acts more
strongly on the liquid crystal molecule 3a than the pretilt
orientation force of the substrate inner surfaces. As a result, the
liquid crystal molecule 3a of the opposite electric field
generation regions S1 and S2 tilts at an incline opposite the
incline of the pretilt resulting from the aligning treatment.
[0075] The opposite tilt of the liquid crystal molecule 3a
resulting from this transversal electric field E (the tilt of the
incline oppose the pretilt incline resulting from the aligning
treatment of the substrate inner surfaces) appears from the section
corresponding to the bending point of the "V" shape. Then, as the
electric field parallel to the substrates E becomes larger, the
opposite tilt region increases, becoming longer along the two
linear sections 42a and 42b.
[0076] FIG. 9 shows the orientation of the long axis of the liquid
crystal molecule 3a of each section within one pixel 100 when an
electric field parallel to the substrates of an intensity that
aligns the liquid crystal molecule 3a near the linear sections 42a
and 42b of the bent electrode 41 of the pixel electrode 4 so that
its long axis is substantially in the direction of 45.degree. with
respect to the aligning treatment directions 1a and 2a is generated
between the pixel electrode 4 and the opposing electrode 5 in a
comparison example wherein the plurality of bent electrodes 41 of
the pixel electrode 4 is formed into a "<" shape where the two
linear sections 42a and 42b directly connect. FIG. 10 shows a
cross-section cut along line X-X of FIG. 9, and FIG. 11 shows a
cross-section cut along line XI-XI of FIG. 9.
[0077] As shown in FIG. 9 to FIG. 11, in the comparative example in
which the plurality of electrode sections 41 of the pixel electrode
4 is formed into a "<" shape where the two linear sections 42a
and 42b directly connect, when a strong electric field parallel to
the substrates E is generated between the pixel electrode 4 and the
opposing electrode 5, the liquid crystal molecule 3a of the region
S1 along the right side border of the linear section 42a of the
upper side and the liquid crystal molecule 3a of the region S2
along the left side border of the linear section 42b of the upper
side in FIG. 9 tilt at an incline opposite (an incline in the
direction away from the back substrate 2 toward the upward left
diagonal direction) the incline of the pretilt (the incline in the
direction away from the back substrate 2 toward the downward right
diagonal direction when viewed from the molecular end side that
appears in bold in the figure) resulting from the aligning
treatment of the substrate inner surfaces.
[0078] As a result, in this comparative example, when a strong
electric field E is generated between the pixel electrode 4 and the
opposing electrode 5, the regions S1 and S2 where the liquid
crystal molecule 3a has been set to an opposite tilt (a tilt of an
incline opposite the incline of the pretilt) and another region
where an opposite tilt of the liquid crystal molecule 3a does not
occur are created. In this comparative example, display
non-uniformity occurs due to the difference in the tilt directions
of the liquid crystal molecule 3a of these regions.
[0079] Contrary to this comparative example, the liquid crystal
display device of the above-described example is formed into a
shape in which the side connecting the section connecting the two
linear sections 42a and 42b of the plurality of bent electrodes 41
of the pixel electrode 4 to one linear section 42a bends in a
direction in which the incline angle with respect to the aligning
treatment directions 1a and 2a increases with respect to the one
linear section 42a. Further, the liquid crystal display device is
formed so that the side connecting to the other linear section 42b
bends in a direction in which the incline angle with respect to the
aligning treatment directions 1a and 2a increases with respect to
the other linear section 42b. As a result, of the electric fields E
parallel to the substrates between the pixel electrode 4 and the
opposing electrode 5, the transversal electric field E generated
between one side border and the other side border of the bent
sections 43a and 43b of the plurality of bent electrodes 41 of the
pixel electrode 4 and the opposing electrode 5 (the electric fields
in the direction orthogonal to the side borders of the bent
sections 43a and 43b) has an intersecting angle with respect to the
aligning treatment directions 1a and 2a that is smaller than that
of the electric E field parallel to the substrates generated
between one side border and the other side border of the linear
sections 42a and 42b of the bent electrode 41 and the opposing
electrode 5, as shown in FIG. 6.
[0080] In this manner, the changed angle .phi.b of the long axis
orientation with respect to the aligning treatment directions 1a
and 2b of the liquid crystal molecule 3a of the regions along one
side border and the other side border of the bent sections 43a and
43b resulting from the transversal electric field E is smaller than
the changed angle .phi.a of the long axis orientation with respect
to the aligning treatment directions 1a and 2a of the liquid
crystal molecule 3a of the regions along one side border and the
other side border of the linear sections 42a and 42b. For this
reason, the orientation restraining force of the alignment film and
the neighboring intermolecular force aligned by this orientation
restraining force act on the liquid crystal molecule 3a of the
regions along one side border and the other side border of the bent
sections 43a and 43b more intensely than the force resulting from
the transversal electric field E. As a result, any change in the
tilt angle of the liquid crystal molecule resulting from the
transversal electric field E is suppressed.
[0081] Further, because the discontinuity of the orientation of the
liquid crystal molecule 3a of the region corresponding to the
linear section 42b of the bottom side with the linear section 42a
of the upper side decreases in the figure of the bent electrode 41
since the bent sections 43a and 43b are connected by a continuous
curve, the change in the tilt angle of the liquid crystal molecule
is suppressed.
[0082] As a result, even when a strong transversal electric field E
that aligns the liquid crystal molecule 3a of the regions along the
linear sections 42a and 42b of the bent electrode 41 of the pixel
electrode 4 so that its long axis is substantially at or near the
direction of 45.degree. with respect to the aligning treatment
directions 1a and 2a is generated between the pixel electrode 4 and
the opposing electrode 5, the long axis orientation is changed in a
state where the liquid crystal molecule is tilted in the incline
direction of the pretilt resulting from the aligning treatment,
without the tilt of the liquid crystal molecule near the bent
section reversing.
[0083] In consequence, a starting point for reversing the tilt of
the liquid crystal molecule 3a of the regions along one side border
and the other side border of the linear sections 42a and 42b of the
bent electrode 41 never occurs in the section corresponding to the
bending point of the bent electrode 41 of a "<" shape, as in the
comparative example shown in FIG. 9 to FIG. 11.
[0084] Then, the connecting sections of the two bent sections 43a
and 43b, which connect the two linear sections 42a and 42b, and the
linear sections 42a and 42b are each formed into a circular arc
shape where one side border and the other side border smoothly
connect. For this reason, the liquid crystal molecule 3a of the
respective regions corresponding to the linear sections 42a and 42b
achieves a substantially continuous aligned state in the bent
sections 43a and 43b.
[0085] In this manner, even when a strong transversal electric
field E that aligns the liquid crystal molecule 3a of the regions
along the linear sections 42a and 42b of the bent electrode 41 of
the pixel electrode 4 so that its long axis is substantially at or
near the direction of 45.degree. with respect to the aligning
treatment directions 1a and 2a is generated between the pixel
electrode 4 and the opposing electrode 5, as shown in FIG. 6 to
FIG. 8, the liquid crystal display device achieves good display
quality without orientation non-uniformity in the regions
corresponding to the plurality of bent electrodes 41 of the pixel
electrode 4.
[0086] Furthermore, in this liquid crystal display device, end bent
sections 44a and 44b respectively connected to the linear sections
42a and 42b and bent in a direction in which the incline angle with
respect to the aligning treatment directions 1a and 2a increases
with respect to the linear sections 42a and 42b are formed at the
respective ends of the two linear sections 42a and 42b of the
plurality of bent electrodes 41 of the pixel electrode 4. As a
result, a transversal electric field E of an orientation having a
smaller intersecting angle with respect to the aligning treatment
directions 1a and 2a than the transversal electric field E
generated between one side border and the other side border of the
linear sections 42a and 42b of the bent electrode 41 and the
opposing electrode 5 is generated between one side border of the
end bent sections 44a and 44b and the opposing electrode 5 as
well.
[0087] That is, a changed angle .phi.c of the long axis orientation
with respect to the aligning treatment directions 1a and 2a of the
liquid crystal molecule 3a of the regions along one side border and
the other side border of the end bent sections 44a and 44b
resulting from the transversal electric field E is smaller than the
changed angle .phi.a of the long axis orientation with respect to
the aligning treatment directions 1a and 2a of the liquid crystal
molecule 3a of the regions along one side border and the other side
border of the linear sections 42a and 42b. With such an
arrangement, an opposite tilt resulting from the transversal
electric field E never occurs with the liquid crystal molecule 3a
of either region along one side border or the other side border of
the end bent sections 44a and 44b, thereby enabling the liquid
crystal display device to change the long axis orientation at the
incline of the pretilt resulting from the aligning treatment. Thus,
the liquid crystal display device more effectively eliminates the
opposite tilt of the liquid crystal molecule 3a resulting from the
transversal electric field E.
[0088] Then, given an incline angle .theta.a of the two linear
sections 42a and 42b of the plurality of bent electrodes 41 of the
pixel electrode 4 with respect to the aligning treatment directions
1a and 2a, and an incline angle .theta.b of the two bent sections
43a and 43b connecting the two linear sections with respect to the
aligning treatment directions 1a and 2a, this liquid crystal
display device defines .theta.a and .theta.b as follows:
0.degree.<.theta.a<20.degree.
20.degree.<.theta.b<40.degree.
[0089] As a result, the liquid crystal display device eliminates
more thoroughly the opposite tilt of the liquid crystal molecule 3a
resulting from the transversal electric field E.
[0090] Further, given a length La of the two linear sections 42a
and 42b of the plurality of bent electrodes 41 of the pixel
electrode 4, and a length Lb of the two bent sections 43a and 43b
connecting the two linear sections 42a and 42b, this liquid crystal
display device defines La and Lb as follows:
La>nLb (n: 3 to 5)
10Lb>La>4Lb.
[0091] As a result, the liquid crystal display device amply
exhibits an opposite tilt prevention effect on the liquid crystal
molecule 3a resulting from the bent section, and substantially
diminishes the effect on the display of the region corresponding to
the bent section.
[0092] Furthermore, this liquid crystal display device defines the
incline angle .theta.c of the end bent sections 44a and 44b
respectively formed at the ends of the two linear sections 42a and
42b of the plurality of bent electrodes 41 of the pixel electrode 4
with respect to the aligning treatment directions 1a and 2a as:
20.degree.<.theta.c<40.degree.
[0093] As a result, this liquid crystal display device eliminates
more thoroughly the opposite tilt of the liquid crystal molecule 3a
resulting from the transversal electric field E.
[0094] Further, this liquid crystal display device defines the
length Lc of the end bent sections 44a and 44b with respect to the
length La of the linear sections 42a and 42b of the bent electrode
41 as a value such that:
La>nLc (n: 3 to 5)
10Lc>La>4Lc.
[0095] As a result, the liquid crystal display device amply
exhibits an opposite tilt prevention effect on the liquid crystal
molecule 3a resulting from the end bent sections 44a and 44b and
substantially diminishes the effect on the display of the region
corresponding to the end bent sections 44a and 44b.
[0096] In this liquid crystal display device, the incline angle
.theta.a of the two linear sections 42a and 42b of the plurality of
bent electrodes 41 of the pixel electrode 4 with respect to the
aligning treatment directions 1a and 2a is preferably set to
5.quadrature..about.15.quadrature.(10.degree..+-.5.degree.) more
preferably to 10.degree..+-.2.degree.. Further, the incline angles
.theta.b and .theta.c of the bent sections 43a and 43b, which
connect the two linear sections 42a and 42b, and of the end bent
sections 44a and 44b with respect to the aligning treatment
directions 1a and 2a are preferably set to
25.quadrature..about.35.hoarfrost. (30.degree..+-.5.degree.), more
preferably to 28.hoarfrost..about.32.hoarfrost.
(30.degree..+-.2.degree.). In this manner, the liquid crystal
display device eliminates more thoroughly the opposite tilt of the
liquid crystal molecule 3a resulting from the transversal electric
field E.
[0097] While the plurality of bent electrodes 41 of the pixel
electrode 4 is commonly connected at both respective ends in the
above-described example, the plurality of bent electrodes 41 may be
commonly connected at one end (the end on the side connected to the
TFT 6).
[0098] Further, while the opposing electrode 5 is formed in a shape
corresponding to the entire area of the pixel 100 in the
above-described example, the opposing electrode 5 may correspond to
at least the area between the plurality of bent electrodes 41 and
41 of the pixel electrode 4.
[0099] Furthermore, for the first and second electrodes provided in
mutual isolation on the inner surface of the back substrate 2, the
liquid crystal display device of the above-described example
employs a plurality of pixel electrodes 4 aligned in a matrix shape
as the first electrode on the side of the liquid crystal layer 3,
and the opposing electrode 5 as the second electrode farther toward
the side of the back substrate 2. However, the liquid crystal
display device may conversely employ an opposing electrode as the
first electrode on the side of the liquid crystal layer 3, and a
plurality of pixel electrodes formed into a matrix shape as the
second electrode farther toward the side of the back substrate 2.
In this case, the liquid crystal display device may form a
plurality of bent electrodes on the opposing electrode, and form
the pixel electrode into a shape that corresponds to the entire
pixel area or that corresponds to the area between the plurality of
bent electrodes of the opposing electrode.
[0100] Further, while the first and second electrodes are provided
on the inner surface of the back substrate 2 in the above-described
example, the first and second electrodes may be provided on the
inner surface of the front substrate 1.
[0101] As described above, the liquid crystal display device of the
present invention comprises a pair of substrates arranged opposite
each other at a predetermined gap having been subjected to an
aligning treatment in mutually parallel directions on each of the
mutually opposed inner surfaces; a liquid crystal layer interposed
in the gap between the pair of substrates and arranged
substantially in parallel with the surfaces of the substrates, with
the long axis of the liquid crystal molecule aligned in the
direction of the aligning treatment; a plurality of first
electrodes that are provided on one of the mutually opposed inner
surfaces of the pair of substrates and comprise, in each
predetermined region for forming a single pixel, one linear section
and another linear section that extend in directions that intersect
the aligning treatment direction at different angles, a bent
section that is provided at each end where the one linear section
and the other linear section adjacent to each other and that
extends in a direction that intersects the aligning treatment
direction at an angle greater than the respective intersecting
angles of the one linear section and the other linear section and
the aligning treatment direction with respect to the aligning
treatment direction, and a connection section that connects these
bent sections; and a second electrode that generates with the first
electrode a transversal electric field for changing the orientation
of the long axis of the liquid crystal molecule within a plane
substantially parallel to the surfaces of the substrates.
[0102] In this liquid crystal display device, the first electrode
preferably comprises a plurality of linear sections long and narrow
in shape that are formed in parallel at a distance from each other,
and connects to each pixel on at least one end of the linear
section. Further, preferably a plurality of slits for forming the
plurality of linear sections is formed on a transparent conductive
film having an area corresponding to a predetermined region for
forming a single pixel, and the first electrode is formed from a
transparent conductive film other than the transparent conductive
film removed as a result of the plurality of slits. Furthermore,
preferably the first electrode forms two regions for aligning the
long axes of the liquid crystal molecules in two different
orientations, a first orientation and a second orientation, when an
electric field is applied between the first electrode and the
second electrode, and one linear section of the first electrode is
formed in one of these two regions, and the other linear section of
the first electrode is formed in the other of the two regions.
Then, the side border of the connection section of the first
electrode is preferably formed into a continuous curved
surface.
[0103] Further, in this liquid crystal display device, the second
electrode is preferably arranged in isolation from the first
electrode, between the first electrode of the one substrate and the
one substrate.
[0104] Furthermore, in the liquid crystal display device, given an
incline angle .theta.a of the one linear section and the other
linear section of the first electrode with respect to the aligning
treatment directions, and an incline angle .theta.b of each of the
bent sections provided at the ends of two adjacent linear sections
with respect to the aligning treatment directions, the incline
angle .theta.a of the linear section and the incline angle .theta.b
of the bent section are preferably set to
0.degree.<.theta.a<20.degree. and
20.degree.<.theta.b<40.degree.. Further, given a length La of
one linear section and the other linear section of the first
electrode, and a length Lb of the bent section, the two lengths La
and Lb are preferably set to La>n Lb (n: 3 to 5) and
10Lb>La>4Lb.
[0105] Then, in the liquid crystal display device, preferably the
first electrode forms an end bent section that is provided on at
least the end of either the one linear section or the other linear
section, in connection to the linear section, on the side opposite
the side where the ends adjacent to each other, and that bends in a
direction in which the incline angle with respect to the aligning
treatment directions increases with respect to the linear section.
In this case, given an incline angle .theta.c of the end bent
section with respect to the aligning treatment directions, the
incline angle .theta.c is preferably set to
20.degree.<.theta.c<40.degree.. Further, given a length La of
the linear section and a length Lc of the end bent section, the
length Lc of the end bent section is preferably set to La>nLc
(n: 3 to 5) and 10Lc>La>4Lc.
[0106] Various examples and changes may be made thereunto without
departing from the broad spirit and scope of the invention. The
above-described example is intended to illustrate the present
invention, not to limit the scope of the present invention. The
scope of the present invention is shown by the attached claims
rather than the example. Various modifications made within the
meaning of an equivalent of the claims of the invention and within
the claims are to be regarded to be in the scope of the present
invention.
[0107] This application is based on Japanese Patent Application No.
2006-263223 filed on Sep. 27, 2006 and including specification,
claims, drawings and summary. The disclosure of the above Japanese
Patent Application is incorporated herein by reference in its
entirety.
* * * * *