U.S. patent application number 13/341727 was filed with the patent office on 2012-04-26 for liquid crystal displays having color dots with embedded polarity regions.
Invention is credited to Hiap L. Ong.
Application Number | 20120099071 13/341727 |
Document ID | / |
Family ID | 43068224 |
Filed Date | 2012-04-26 |
United States Patent
Application |
20120099071 |
Kind Code |
A1 |
Ong; Hiap L. |
April 26, 2012 |
Liquid Crystal Displays Having Color Dots With Embedded Polarity
Regions
Abstract
A multi-domain liquid crystal display is disclosed. The display
includes embedded polarity regions within the color dots of the
display. Specifically, the embedded polarity regions have a
polarity that is different from the polarity of the color dot
containing the embedded polarity region. This difference in
polarity enhances the fringe fields of the color dot or in some
situations may create additional fringe fields. The enhanced fringe
fields or additional fringe fiends can more quickly restore liquid
crystals to their proper position.
Inventors: |
Ong; Hiap L.; (Warren,
NJ) |
Family ID: |
43068224 |
Appl. No.: |
13/341727 |
Filed: |
December 30, 2011 |
Related U.S. Patent Documents
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Application
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Filing Date |
Patent Number |
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12721536 |
Mar 10, 2010 |
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13341727 |
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12573085 |
Oct 2, 2009 |
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12721536 |
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11751454 |
May 21, 2007 |
8107030 |
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12573085 |
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11751454 |
May 21, 2007 |
8107030 |
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12721536 |
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11751387 |
May 21, 2007 |
7956958 |
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11751454 |
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11227595 |
Sep 15, 2005 |
7630033 |
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11751387 |
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12492098 |
Jun 25, 2009 |
8040472 |
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12721536 |
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11227595 |
Sep 15, 2005 |
7630033 |
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12492098 |
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Current U.S.
Class: |
349/144 |
Current CPC
Class: |
G09G 2320/028 20130101;
G02F 2201/123 20130101; G09G 3/3648 20130101; G09G 2300/0439
20130101; G02F 1/1393 20130101; G09G 2300/0452 20130101; G09G
3/3614 20130101; G09G 2300/0491 20130101; G02F 1/133707 20130101;
G09G 2320/0242 20130101 |
Class at
Publication: |
349/144 |
International
Class: |
G02F 1/1343 20060101
G02F001/1343 |
Claims
1. A pixel comprising: a first first-component color dot having a
first edge and a second edge; a first first-component embedded
electrode, wherein the first first-component embedded electrode is
underneath the first edge of the first first-component color dot
and the second edge of the first first-component color dot; and an
insulating layer separating the first first-component embedded
electrode from the first first-component color dot.
2. The pixel of claim 1, wherein the first first-component embedded
electrode is also underneath a third edge of the first
first-component color dot and a fourth edge of the first
first-component color dot.
3. The pixel of claim 1, further comprising a first switching
element coupled to the first first-component color dot.
4. The pixel of claim 3, wherein the first first-component embedded
electrode is configured to have a first polarity when the first
switching element is configured to have a second polarity.
5. The pixel of claim 1, further comprising: a first
second-component color dot having a first edge and a second edge; a
first second-component embedded electrode, wherein the first
second-component embedded electrode is underneath the first edge of
the first second-component color dot and the second edge of the
first second-component color dot; and wherein the insulating layer
separates the first second-component embedded electrode from the
first second-component color dot.
6. The pixel of claim 5, further comprising: a first
third-component color dot having a first edge and a second edge; a
first third-component embedded electrode, wherein the first
third-component embedded electrode is underneath the first edge of
the first third-component color dot and the second edge of the
first third-component color dot; and wherein the insulating layer
separates the first third-component embedded electrode from the
first third-component color dot.
7. The pixel of claim 6 wherein the first first-component embedded
electrode is coupled to the first second-component embedded
electrode and the first third-component electrode.
8. The pixel of claim 6 further comprising: a first switching
element coupled to the first first-component color dot; a second
switching element coupled to the first second-component color dot;
a third switching element coupled to the first third-component
color dot;
9. The pixel of claim 8, wherein the first switching element and
the third switching element are configured to have a first polarity
when the second switching element has a second polarity.
10. The pixel of claim 9, wherein the first first-component
embedded electrode and the first third-component embedded electrode
are configured to have the second polarity when the second
switching element has the second polarity.
11. The pixel of claim 8, wherein the first switching element, the
second switching element, and the third switching element are
configured to have a first polarity when the first first-component
embedded electrode, the first second-component embedded electrode,
and the first third-component embedded electrode are configured to
have a second polarity.
12. The pixel of claim 3, further comprising: a second
first-component color dot having a first edge and a second edge,
wherein the second first-component color dot is coupled to the
first switching element; a second first-component embedded
electrode, wherein the second first-component embedded electrode is
underneath the first edge of the second first-component color dot
and the second edge of the second first-component color dot.
13. The pixel of 12, wherein the first first-component embedded
electrode is coupled to the second first-component electrode.
14. The pixel of claim 12, further comprising a first fringe field
amplifying region having a first horizontal amplifying portion
between the first first-component color dot and the second first
component color dot.
15. The pixel of claim 14, wherein the first first-component
embedded electrode is coupled to the first fringe field amplifying
region and wherein the second first-component embedded electrode is
coupled to the first fringe field amplifying region.
16. The pixel of claim 12, further comprising: a first
second-component color dot having a first edge and a second edge; a
first second-component embedded electrode, wherein the first
second-component embedded electrode is underneath the first edge of
the first second-component color dot and the second edge of the
first second-component color dot; a second second-component color
dot having a first edge and a second edge; a second
second-component embedded electrode, wherein the second
second-component embedded electrode is underneath the first edge of
the second second-component color dot and the second edge of the
second second-component color dot; and a second switching element
coupled to the first second-component color dot and the second
second-component color dot.
17. The pixel of claim 16, wherein the first first-component
embedded electrode is coupled to the first second component
embedded electrode.
18. The pixel of claim 17, wherein the second first-component
embedded electrode is coupled to the second second-component
embedded electrode.
19. The pixel of claim 16, further comprising: a first fringe field
amplifying region having a first horizontal amplifying portion
between the first first-component color dot and the second first
component color dot; and a second fringe field amplifying region
having a first horizontal amplifying portion between the first
second-component color dot and the second second-component color
dot.
20. The pixel of claim 19, wherein the first fringe field
amplifying region further comprises a vertical amplifying portion
between the first first-component color dot and the first
second-component color dot and between the second first-component
color dot and the second second-component color dot.
21. The pixel of claim 19, wherein the first first-component
embedded electrode is coupled to the first fringe field amplifying
region; wherein the second first first-component embedded electrode
is coupled to the first fringe field amplifying region; wherein the
first second-component embedded electrode is coupled to the second
fringe field amplifying region; and wherein the second
second-component embedded electrode is coupled to the second fringe
field amplifying region.
Description
RELATED APPLICATIONS
[0001] The present application is a Continuation-In-Part of and
claims the benefit of U.S. Utility patent application Ser. No.
12/573,085 entitled "Pixels having Fringe Field Amplifying Regions
for Multi-Domain Vertical Alignment Liquid Crystal Displays" by
Hiap L. Ong, filed Oct. 2, 2009, which is incorporated herein in
its entirety by reference. U.S. Utility patent application Ser. No.
12/573,085, is also a Continuation-In-Part of and claimed the
benefit of U.S. Utility patent application Ser. No. 11/751,454
(Publication serial number US 2008/0002072 A1), entitled "Pixels
Using Associated Dot Polarity for Multi-Domain Vertical Alignment
Liquid Crystal Displays" by Hiap L. Ong, filed May 21, 2007, which
is incorporated herein in its entirety by reference. U.S. Utility
patent application Ser. No. 11/751,454 claimed the benefit of U.S.
Provisional Patent Application Ser. No. 60/799,815, entitled
"Multi-domain Vertical Alignment liquid crystal display with row
inversion drive scheme", by Hiap L. Ong, filed May 22, 2006; and
U.S. Provisional Patent Application Ser. No. 60/799,843, entitled "
Method To Conversion of Row Inversion To Have Effective Pixel
Inversion Drive Scheme", by Hiap L. Ong, filed May 22, 2006.
[0002] The present application is also a Continuation-In-Part of
and claims the benefit of U.S. Utility patent application Ser. No.
11/751,454 (Publication serial number US 2008/0002072 A1), entitled
"Pixels Using Associated Dot Polarity for Multi-Domain Vertical
Alignment Liquid Crystal Displays" by Hiap L. Ong, filed May 21,
2007, which is incorporated herein in its entirety by reference.
U.S. Utility patent application Ser. No. 11/751,454 claimed the
benefit of U.S. Provisional Patent Application Ser. No. 60/799,815,
entitled "Multi-domain Vertical Alignment liquid crystal display
with row inversion drive scheme", by Hiap L. Ong, filed May 22,
2006; and U.S. Provisional Patent Application Ser. No. 60/799,843,
entitled " Method To Conversion of Row Inversion To Have Effective
Pixel Inversion Drive Scheme", by Hiap L. Ong, filed May 22,
2006.
[0003] The present application is also a Continuation-In-Part of
and claims the benefit of U.S. Utility patent application Ser. No.
11/751,387 (Publication serial number US 2009/00262271A1), entitled
"Large Pixel Multi-Domain Vertical Alignment Liquid Crystal Display
Using Fringe Fields" by Hiap L. Ong, filed May 21, 2007, and is
incorporated herein in its entirety by reference. U.S. Utility
patent application Ser. No. 12/751,387 is a continuation-in-part of
U.S. Utility patent application Ser. No. 11/227,595 (now issued as
U.S. Pat. No. 7,630,033), entitled "Large Pixel multi-domain
vertical alignment liquid crystal display using fringe fields" by
Hiap L. Ong, filed Sep. 15, 2005, and is incorporated herein in its
entirety by reference.
[0004] The present application is a Continuation-In-Part of and
claims the benefit of U.S. Utility patent application Ser. No.
12/492,098 (Publication serial number US 2009/00262271A1), entitled
"Large Pixel Multi-Domain Vertical Alignment Liquid Crystal Display
Using Fringe Fields" by Hiap L. Ong, filed Jun. 25, 2009, and is
incorporated herein in its entirety by reference. U.S. Utility
patent application Ser. No. 12/492,098 is a divisional of U.S.
Utility patent application Ser. No. 11/227,595 (now issued as U.S.
Pat. No. 7,630,033), entitled "Large Pixel multi-domain vertical
alignment liquid crystal display using fringe fields" by Hiap L.
Ong, filed Sep. 15, 2005, and is incorporated herein in its
entirety by reference.
BACKGROUND OF THE INVENTION
[0005] 1. Field of the Invention
[0006] The present invention relates to liquid crystal displays
(LCDs). More specifically, the present invention relates
large-pixel multi-domain vertical alignment LCDs, which can be
manufactured with smooth substrates.
[0007] 2.Discussion of Related Art
[0008] Liquid crystal displays (LCDs), which were first used for
simple monochrome displays, such as calculators and digital
watches, have become the dominant display technology. LCDs are used
routinely in place of cathode ray tubes (CRTs) for both computer
displays and television displays. Various drawbacks of LCDs have
been overcome to improve the quality of LCDs. For example, active
matrix displays, which have largely replaced passive matrix
displays, reduce ghosting and improve resolution, color gradation,
viewing angle, contrast ratios, and response time as compared to
passive matrix displays.
[0009] However, the primary drawback of conventional twisted
nematic LCDs is the viewing angle is very narrow and the contrast
ratio is low. Even the viewing angle of active matrixes is much
smaller than the viewing angle for CRT. Specifically, while a
viewer directly in front of an LCD receives a high quality image,
other viewers to the side of the LCD would not receive a high
quality image. Multi-domain vertical alignment liquid crystal
displays (MVA LCDs) were developed to improve the viewing angle and
contrast ratio of LCDs. FIGS. 1(a)-1(c) illustrate the basic
functionality of a pixel of a vertical alignment LCD 100. For
clarity, the LCD of FIG. 1 uses only a single domain. Furthermore,
for clarity, the LCDs of FIGS. 1(a)-1(c) (and FIG. 2) described in
terms of gray scale operation. Furthermore, FIGS. 1(a)-1(c) is
simplified to clarity and omits many processing layers. For
example, between substrate 110 and electrode 120, actual displays
would likely include various metal layers used for electrical
connections as well as insulating layers that separate the metal
layers.
[0010] LCD 100 has a first polarizer 105, a first substrate 110, a
first electrode 120, a first alignment layer 125, liquid crystals
130, a second alignment layer 140, a second electrode 145, a second
substrate 150, and a second polarizer 155. Generally, first
substrate 110 and second substrate 150 are made of a transparent
glass. First electrode 120 and second electrode 145 are made of a
transparent conductive material such as ITO (Indium Tin Oxide).
First alignment layer 125 and second alignment layer 140, which are
typically made of a polyimide (PI) layer, align liquid crystals 130
vertically in a resting state. In operation, a light source (not
shown) sends light from beneath first polarizer 105, which is
attached to first substrate 110. First polarizer 105 is generally
polarized in a first direction and second polarizer 155, which is
attached to second substrate 150, is polarized perpendicularly to
first polarizer 105. Thus, light from the light source would not
pass through both first polarizer 105 and second polarizer 155
unless the light polarization were to be rotated by 90 degrees
between first polarizer 105 and second polarizer 155. For clarity,
very few liquid crystals are shown. In actual displays, liquid
crystals are rod like molecules, which are approximately 5
angstroms in diameter and 20-25 angstroms in length. Thus, there
are over 12 million liquid crystal molecules in a pixel that is 120
.mu.m width by 300 .mu.m length by 3 .mu.m height. Although not
shown, many liquid crystal displays (particularly active matrix
LCDs) include a passivation layer on bottom of first electrode 120.
The passivation layer serves as an insulating layer between the
first electrode 120 and devices and conductors that may be formed
on the substrate. The passivation layer is commonly formed using
silicon nitrides.
[0011] In FIG. 1(a), liquid crystals 130 are vertically aligned. In
the vertical alignment, liquid crystals 130 would not rotate light
polarization from the light source. Thus, light from the light
source would not pass through LCD 100 and gives a completely
optical black state and a very high contrast ratio for all color
and all cell gap. Consequently MVA LCDs provide a big improvement
on the contrast ratio over the conventional low contrast twisted
nematic LCDs. However, as illustrated in FIG. 1(b), when an
electric field is applied between first electrode 120 and second
electrode 145, liquid crystals 130 reorientate to a tilted
position. Liquid crystals in the tilted position rotate the
polarization of the polarized light coming through first polarizer
105 by ninety degrees so that the light can then pass through
second polarizer 155. The amount of tilting, which controls the
amount of light passing through the LCD (i.e., brightness of the
pixel), is proportional to the strength of the electric field.
Generally, a single thin-film-transistor (TFT) is used for each
pixel. However for color displays, a separate TFT is used for each
color component (typically, Red, Green, and Blue)
[0012] However, the light passing through LCD 120 is not uniform to
viewers at different viewing angles. As illustrated in FIG. 1(c), a
viewer 172 that is left of center would see a bright pixel because
the broad (light rotating) side of liquid crystals 130 face viewer
172. A viewer 174 that is centered on the pixel would see a gray
pixel because the broad side of liquid crystals 130 is only
partially facing viewer 174. A viewer 176 that is right of center
would see a dark pixel because the broad side of liquid crystals
130 is barely facing viewer 176.
[0013] Multi-domain vertical alignment liquid crystal displays (MVA
LCDs) were developed to improve the viewing angle problems of
single-domain vertical alignment LCDs. FIG. 2 illustrates a pixel
of a multi-domain vertical alignment liquid crystal display (MVA
LCD) 200. MVA LCD 200 includes a first polarizer 205, a first
substrate 210, a first electrode 220, a first alignment layer 225,
liquid crystals 235, liquid crystals 237, protrusions 260s, a
second alignment layer 240, a second electrode 245, a second
substrate 250, and a second polarizer 255. Liquid crystals 235 form
the first domain of the pixel and liquid crystals 237 form the
second domain of the pixel. When an electric field is applied
between first electrode 220 and second electrode 245, protrusions
260 cause liquid crystals 235 to tilt in a different direction than
liquid crystals 237. Thus, a viewer 272 that is left of center
would see the left domain (liquid crystals 235) as black and the
right domain (liquid crystals 237) as white. A viewer 274 that is
centered would see both domains as gray. A viewer 276 that is right
of center would see the left domain as white and the right domain
as black. However, because the individual pixels are small, all
three viewers would perceive the pixel as being gray. As explained
above, the amount of tilting of the liquid crystals is controlled
by the strength of the electric field between electrodes 220 and
245. The level of grayness perceived by the viewer directly related
to the amount of tilting of the liquid crystals. MVA LCDs can also
be extended to use four domains so that the LC orientation in a
pixel is divided into 4 major domains to provide wide symmetrical
viewing angles both vertically and horizontally.
[0014] Thus, multi-domain vertical alignment liquid crystal
displays, provide wide symmetrical viewing angles, however, the
cost of manufacturing MVA LCDs are very high due to the difficulty
of adding protrusions to the top and bottom substrates and the
difficulty of properly aligning the protrusions on the top and
bottom substrates. Specifically, a protrusion on the bottom
substrate must be located at the center of two protrusions on the
top substrate; any misalignment between the top and bottom
substrates will reduce the product yield. Other techniques of using
physical features to the substrates, such as ITO slits, which have
been used in place of or in combination with the protrusions, are
also very expensive to manufacture. Furthermore, the protrusions
and ITO slits inhibit light transmission and thus reduce the
brightness of the MVA LCDs.
[0015] However, MVA LCDs have been developed that do not require
the use of physical features (such as protrusions or ITO slits) on
the substrate. Specifically, these MVA LCDs use fringe fields to
create multiple-domains. Without the requirement of physical
features the difficulty of aligning the physical features of the
top and bottom substrate is eliminated. Thus, MVA LCDs using fringe
fields have higher yield and are less expensive to manufacture than
MVA LCDs that use physical features on the substrates.
[0016] FIGS. 3(a) and 3(b) illustrate the basic concept used to
create a multi-domain vertical alignment liquid crystal display
(MVA LCD) 300 without resorting to physical features on the
substrates. Specifically FIG. 3 shows pixels 310, 320, and 330 in
between a first substrate 305 and a second substrate 355. A first
polarizer 302 is attached to first substrate 305 and a second
polarizer 357 is attached to second substrate 355. Pixel 310
includes a first electrode 311, liquid crystals 312, liquid
crystals 313 and a second electrode 315. Pixel 320 includes a first
electrode 321, liquid crystals 322, liquid crystals 323 and a
second electrode 325. Similarly, pixel 330 includes a first
electrode 331, liquid crystals 332, liquid crystals 333 and a
second electrode 335. Although not shown, many liquid crystal
displays include a passivation layer on top of electrodes 311, 321,
and 331. The electrodes are typically constructed using a
transparent conductive material such as ITO. Furthermore, a first
alignment layer 307 covers the electrodes on first substrate 305.
Similarly a second alignment layer 352 covers the electrodes on
second substrate 355. Both LC alignment layers 307 and 352 provide
a vertical LC alignment. As explained in more detail below,
electrodes 315, 325, and 335 are held at a common voltage V_Com.
Therefore, to ease manufacturing, electrodes 315, 325, and 335 are
created as a single structure (as shown in FIGS. 3(a) and 3(b)).
MVA LCD 300 operates pixels 310, 320, and 330 using alternating
polarities. For example, if the polarities of pixels 310 and 330
are positive then the polarity of pixel 320 would be negative.
Conversely, if the polarities of pixel 310 and 330 are negative
then the polarity of pixel 320 would be positive. Generally, the
polarity of each pixel would switch between frames, but the pattern
of alternating polarities is maintained in each frame. In FIG.
3(a), pixels 310, 320, and 330 are in the "OFF" state, i.e. with
the electric field between the first and second electrodes turned
off. In the "OFF" state some residual electric field may be present
between the first and second electrode. However, the residual
electric field is generally too small to tilt the liquid
crystals.
[0017] In FIG. 3(b), pixels 310, 320, and 330 are in the "ON"
state. 3(b) uses "+" and "-" to denote the voltage polarity of the
electrodes. Thus, electrodes 311, and 331 have positive voltage
polarity and electrodes 321 has negative voltage polarity.
Substrate 355 and electrodes 315, 325, and 335 are kept at common
voltage V_com. The voltage polarity is defined with respect to the
V_com voltage, where a positive polarity is obtained for voltages
higher than V_com, and a negative polarity is obtained for voltage
smaller than V_com. Electric field 327 (illustrated using field
lines) between electrodes 321 and 325 causes liquid crystals 322
and liquid crystals 323 to tilt. In general, without protrusions or
other features the tilting direction of the liquid crystals is not
fixed for liquid crystals with a vertical LC alignment layers at
307 and 352. However, the fringe field at the edges of the pixel
can influence the tilting direction of the liquid crystals. For
example, electric field 327 between electrode 321 and electrode 325
is vertical around the center of pixel 320 but is tilted to the
left in the left part of the pixel, and tiled to the right in the
right part of the pixel. Thus, the fringe field between electrode
321 and electrode 325 cause liquid crystals 323 to tilt to the
right to form one domain and cause liquid crystals 322 to tilt to
the left to from a second domain. Thus, pixel 320 is a multi-domain
pixel with a wide symmetrical viewing angle
[0018] Similarly, the electric field (not shown) between electrode
311 and electrode 315 would have fringe fields that cause liquid
crystals 313 to reorientate and tilt to the right in the right side
in pixel 312 and cause liquid crystals 312 to tilt to the left in
the left side in pixel 310. Similarly, the electric field (not
shown) between electrode 331 and electrode 335 would have fringe
fields that cause liquid crystals 333 to tilt to the right in the
right side in pixel 330 and cause liquid crystals 332 to tilt to
the left in the left side in pixel 330.
[0019] Alternating polarity of adjacent pixels amplifies the fringe
field effect in each pixel. Therefore, by repeating the alternating
polarity pattern between rows of pixels (or columns of pixels), a
multi domain vertical alignment LCD is achieved without physical
features. Furthermore, an alternating polarity checkerboard pattern
can be used to create four domains in each pixel.
[0020] However, fringe field effects are relatively small and weak,
in general. Consequently, as pixels become larger, the fringe
fields at the edge of the pixels would not reach all the liquid
crystals within a pixel. Thus, in large pixels the direction of
tilting for the liquid crystals not near the edge of the pixels
would exhibit random behavior and would not produce a multi-domain
pixel. Generally, fringe field effects of pixels would not be
effective to control liquid crystal tilt when the pixels become
larger than 40-60 .mu.m. Therefore, for large pixel LCDs pixel
division methods are used to achieve multi-domain pixels.
Specifically, for color LCDs, pixels are divided into color
components. Each color component is controlled by a separate
switching element, such as a thin-film transistor (TFT). Generally,
the color components are red, green, and blue. The color components
of a pixel are further divided into color dots.
[0021] The polarity of each pixel switches between each successive
frame of video to prevent image quality degradation, which may
result from twisting the liquid crystals in the same direction in
every frame. However, the dot polarity pattern switching may cause
other image quality issues such as flicker if all the switching
elements are of the same polarity. To minimize flicker, the
switching elements (e.g. are transistors) are arranged in a
switching element driving scheme that include positive and negative
polarities. Furthermore, to minimize cross talk the positive and
negative polarities of the switching elements should be arranged in
a uniform pattern, which provides a more uniform power
distribution. The three main switching element driving schemes are
switching element point inversion driving scheme, switching element
row inversion driving scheme, and switching element column
inversion driving scheme. In the switching element point inversion
driving scheme, the switching elements form a checkerboard pattern
of alternating polarities. In the switching element row inversion
driving scheme, the switching elements on each row have the same
polarity; however, each switching element in one row has the
opposite polarity as compared to the polarity of switching elements
in adjacent rows. In the switching element column inversion driving
scheme, the switching elements on each column have the same
polarity; however, a switching element in one column has the
opposite polarity as compared to the polarity of switching elements
in adjacent columns. While the switching element point inversion
driving scheme provides the most uniform power distribution, the
complexity and additional costs of switching element point
inversion driving scheme over switching element row inversion
driving scheme or switching element column inversion driving scheme
may not be cost effective. Thus, most LCD displays for low cost or
low voltage applications are manufactured using switching element
row inversion driving scheme while switching element point
inversion driving scheme is usually reserved for high performance
applications.
[0022] Pixels may include various key components arranged to
achieve high quality low cost display units. For example, pixel can
include color components, color dots, fringe field amplifying
regions (FFAR), switching elements, device component areas, and
associated dots. Displays using these various components are
described in U.S. Patent Application "Cite various KYO Patents
KYO-001 KYO-003, KYO-005, KYO-006", which are incorporated herein
by reference.
[0023] Device component area encompasses the area occupied by the
switching elements and/or storage capacitor as well as the area
that was used to manufacture the switching elements and/or storage
capacitors. For clarity, a different device component area is
defined for each switching element.
[0024] Associated dots and fringe field amplifying regions are
polarized areas that are not part of the color components.
Associated dots cover the device component areas. Generally, the
associated dots are manufactured by depositing an insulating layer
over the switching element and/or storage capacitors. Followed by
depositing an electrically conductive layer to form the associated
dot. The associated dots are electrically connected to specific
switching element and or other polarized components (such as color
dots). The storage capacitors are electrically connected to
specific switching element and color dot electrodes to compensate
and offset the capacitance change on the liquid crystal cells
during the switching-on and switching-off processes of the liquid
crystal cells. Consequently, the storage capacitors are used to
reduce the cross-talk effects during the switching-on and
switching-off processes of the liquid crystal cells. A patterning
mask is used when it is necessary to form the patterned electrode
for the associated dots. A color layer is added to form a light
shield for the associated dot. In general, the color layer is black
however some displays use different color to achieve a desired
color pattern or shading. Generally, the color layer is achieved by
depositing a color filter layer on the corresponding ITO glass
substrate. Specifically, a patterned color filter layer is
deposited between second substrate 150 and second electrode 140
with pattern corresponding to the color for the color dot and
associated dots. However, some displays may also place a patterned
color filter layer underneath the electrode layer of the color
dots, associated dots, or DCA on the substrate.
[0025] In some displays, the associated dot is an area independent
of the switching elements. Furthermore, displays have additional
associated dots not directly related to the switching elements.
Generally, the associated dot includes an active electrode layer
such as ITO or other conductive layer, and is connected to a nearby
color dot or powered in some other manner. For opaque associated
dots, a black matrix layer can be added on the bottom of the
conductive layer to form the opaque area. The black matrix can be
fabricated on the ITO glass substrate side to simplify the
fabrication process. The additional associated dots improve the
effective use of display area to improve the aperture ratio and to
form the multiple liquid crystal domains within the color dots.
Some displays also use associate dots to improve color performance.
For example, careful placement of associated dots can allow the
color of nearby color dots to be modified from the usual color
pattern.
[0026] Fringe field amplifying regions are more versatile than
associated dots. Specifically, fringe field amplifying regions may
have non-rectangular shapes, although generally, the overall shape
of the fringe field amplifying regions can be divided into a set of
rectangular shapes. Furthermore, fringe field amplifying regions
extend along more than one side of a color dot. In addition, fringe
field amplifying regions may be used in place of associated dots in
some displays. Specifically, in these displays the fringe field
amplifying region cover the device component areas but also extend
along more than one side of color dots adjacent to the device
component areas.
[0027] In general, the color dots, device component areas, and
associated dots are arranged in a grid pattern and are separated
from adjacent neighbors by a horizontal dot spacing HDS and a
vertical dot spacing VDS. When fringe field amplifying regions are
used in place of associated dots, part of the fringe field
amplifying regions would also fit in the grid pattern. In some
displays multiple vertical dot spacings and multiple horizontal dot
spacings may be used. Each color dot, associated dot, and device
component area has two adjacent neighbors (e.g. color dots,
associated dots, or device component areas) in a first dimension
(e.g. vertical) and two adjacent neighbors in a second dimension
(e.g. horizontal). Furthermore, two adjacent neighbors can be
aligned or shifted. Each color dot has a color dot height CDH and a
color dot width CDW. Similarly, each associated dot has an
associated dot height ADH and an associated dot width ADW.
Furthermore, each device component area has device component area
height DCAH and a device component area width DCAW. In some
displays, color dots, associated dots and device component areas
are the same size. However in many displays color dots, associated
dots and device component areas could be of different size or
shapes. For example in many displays associated dots have a smaller
height than color dots.
[0028] When a LCD panel is subject to external touch pressure on
the panel substrate, touch mura occurs. Touch mura effects due to
physical disturbance of the liquid crystals is a major issue with
vertically aligned liquid crystal displays (both single domain and
multiple domain). Touch mura effects refer to irregular patterns or
regions causing uneven screen uniformity. Physical disturbance of
the liquid crystals may be caused by shaking, vibration, and
pressure on the display. In particular, vertically aligned liquid
crystal displays are very susceptible to touch mura effects caused
by pressure on the display. Specifically, pressure on a vertically
aligned liquid crystal display may flatten the liquid crystals and
cause a disturbance effect on the display. Unfortunately, devices
incorporating touch screen functionality (i.e. users of a device
apply pressure on the surface of the display as a means of
providing user input to the device) has become increasingly popular
which may hinder acceptance of vertically aligned liquid crystal
displays. Hence there is a need for a method or system to minimize
touch mura effects in a vertically aligned liquid crystal
display.
SUMMARY
[0029] Accordingly, the present invention provides a vertically
aligned liquid crystal display with reduced touch mura effects.
Specifically, embodiments of the present invention use novel pixel
designs that have color dots with embedded polarity regions (EPR)
which amplifies fringe fields that more quickly restore the liquid
crystals to their proper positions. For example, in accordance with
one embodiment of the present invention, pixels are sub-divided
into color components having one or more color dots (CDs).
Furthermore in some embodiments of the present invention, the
embedded polarity regions can be used to create or enhance fringe
field effects that can induce multiple domains in the liquid
crystals to enhance the viewing angle of the display.
[0030] In one embodiment of the present invention, a display
includes a first pixel having a first first-pixel switching
element; a first electrode coupled to the first first-pixel
switching element, and a second pixel. The second pixel includes a
first second-pixel color component that includes a first
second-pixel first-component color dot and a second second-pixel
first-component color dot. The second pixel also includes a first
second-pixel switching element coupled to the first second-pixel
first-component color dot and a second second-pixel first-component
color dot. The first electrode is located between the first
second-pixel first-component color dot and a second second-pixel
first-component color dot. The first second-pixel first-component
color dot includes a first embedded polarity region and a second
second-pixel first-component color dot includes a second embedded
polarity region. In general, when the first first-pixel switching
element is configured to have a first polarity, the first
second-pixel switching element is configured to have a second
polarity. The first electrode could be for example a color dot, an
associated dot, or a fringe fiend amplifying region.
[0031] The present invention will be more fully understood in view
of the following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIGS. 1(a)-1(c) are three illustrations of a pixel of a
conventional single domain vertical alignment LCD.
[0033] FIG. 2 is an illustration of a pixel of a conventional
multi-domain vertical alignment LCD.
[0034] FIGS. 3(a)-3(b) illustrate a multi-domain vertical alignment
liquid crystal display in accordance with one embodiment of the
present invention.
[0035] FIGS. 4(a)-4(b) illustrate a pixel design in accordance with
one embodiment of the present invention.
[0036] FIGS. 5(a)-5(b) illustrate a color dot in accordance with
one embodiment of the present invention.
[0037] FIGS. 6(a)-6(c) illustrate a color dot in accordance with
one embodiment of the present invention.
[0038] FIGS. 7(a)-7(c) illustrate a color dot in accordance with
one embodiment of the present invention.
[0039] FIGS. 8(a)-8(c) illustrate a color dot in accordance with
one embodiment of the present invention.
[0040] FIGS. 9(a)-9(c) illustrate a color dot in accordance with
one embodiment of the present invention.
[0041] FIGS. 10(a)-10(c) illustrate a color dot in accordance with
one embodiment of the present invention.
[0042] FIGS. 11(a)-11(c) illustrate a color dot in accordance with
one embodiment of the present invention.
[0043] FIG. 12 illustrates a color dot in accordance with one
embodiment of the present invention.
[0044] FIGS. 13(a)-13(c) illustrate a color dot in accordance with
one embodiment of the present invention.
[0045] FIGS. 14(a)-14(b) illustrate a color dot in accordance with
one embodiment of the present invention.
[0046] FIGS. 15(a)-15(d) illustrate a pixel design in accordance
with one embodiment of the present invention.
[0047] FIG. 15(e) illustrates a portion of a display in accordance
with one embodiment of the present invention.
[0048] FIGS. 16(a)-16(c) illustrate a pixel design in accordance
with one embodiment of the present invention.
[0049] FIG. 16(d) illustrates a portion of a display in accordance
with one embodiment of the present invention.
[0050] FIG. 16(e) illustrates a portion of a display in accordance
with one embodiment of the present invention.
[0051] FIG. 16(f) illustrates a portion of a display in accordance
with one embodiment of the present invention.
[0052] FIGS. 17(a)-17(b) illustrate a pixel design in accordance
with one embodiment of the present invention.
[0053] FIG. 17(c) illustrates a pixel design in accordance with one
embodiment of the present invention.
[0054] FIG. 17(d) illustrates a portion of a display in accordance
with one embodiment of the present invention.
[0055] FIG. 17(e) illustrates a portion of a display in accordance
with one embodiment of the present invention.
DETAILED DESCRIPTION
[0056] As explained above, conventional vertically aligned LCDs are
very susceptible to touch mura effects caused by physical
disturbances to the liquid crystals. However, vertically aligned
LCDs in accordance with the principles of the present invention use
color dots that have embedded polarity regions (EPR) that enhance
additional lateral fringe fields that help restore the liquid
crystals to their proper orientation after a physical disturbance.
Thus, vertically aligned LCDs in accordance with the present
invention can quickly resolve touch mura effects caused by physical
disturbance of the liquid crystals.
[0057] FIGS. 4(a) and 4(b) show different dot polarity patterns of
a pixel design 410 (labeled 410+ and 410- as described below) in
accordance with one embodiment of the present invention. In actual
operation a pixel will switch between a first dot polarity pattern
and a second dot polarity pattern between each image frame. For
clarity, the dot polarity pattern, in which the first color dot of
the first color component has a positive polarity, is referred to
as the positive dot polarity pattern. Conversely, the dot polarity
pattern in which the first color dot of the first color component
has a negative polarity is referred to as the negative dot polarity
pattern. Specifically, in FIG. 4(a), pixel design 410 has a
positive dot polarity pattern (and is thus labeled 410+) and in
FIG. 4(b), pixel design 410 has a negative dot polarity pattern
(and is thus labeled 410-). Furthermore, the polarity of each
polarized component in the various pixel designs are indicated with
"+" for positive polarity or "-" for negative polarity.
[0058] Pixel design 410 has three color components CC_1, CC_2 and
CC_3. Each of the three color components includes one color dots.
For clarity, the color dots are referenced as CD_X_Y, where X is a
color component (from 1 to 3 in FIGS. 4(a)-4(b)) and Y is a dot
number (In FIGS. 4(a)-4(b) Y is always 1). Pixel design 410 also
includes a switching element for each color component (referenced
as SE_1, SE_2, and SE_3) and a device component area for each color
component (referenced as DCA_1, DCA_2, and DCA_3). Switching
elements SE_1, SE_2, and SE_3 are arranged in a row. Device
component areas DCA_1, DCA_2, and DCA_3 surround switching elements
SE_1, SE_2, and SE_3, respectively.
[0059] First color component CC_1 of pixel design 410 has one color
dots CD_1_1. Color dots CD_1_1 is horizontally aligned with drive
component area DCA_1 and vertically separated from drive component
area DCA_1 by a vertical dot spacing VDS1. Switching element SE_1
is coupled to the electrodes of color dot CD_1_1 to control the
polarity of color dot CD_1_1. Color dot CD_1_1 includes an embedded
polarity region EPR_1_1_1. For clarity, the embedded polarity
regions are referenced as EPR_X_Y_Y, where X is a color component,
Y is a dot number, and Z is enumerates the embedded polarity
regions within a color dot. Embedded polarity regions can have
different shapes. For example, in pixel design 410 embedded
polarity regions have a square shape. However other embodiments may
have circular shapes, polygonal shapes (such as squares and
hexagons), or even other irregular shapes.
[0060] In general polarity refers to the direction of polarity
usually denoted as positive or negative. More precisely, polarity
also includes a magnitude of polarity. Embedded polarity regions
may have the same direction of polarity (i.e. positive or negative)
as the color dot but have a different magnitude of polarity.
Furthermore, embedded polarity regions may have different polarity
(i.e. "direction of polarity") than the color dot (e.g. positive
polarity for color dot polarity with negative polarity for embedded
polarity regions). In addition, embedded polarity regions can have
neutral polarity. Different embodiments of the present invention
use different novel techniques or combination of novel techniques
to create the embedded polarity regions within the color dots.
These techniques are described in detail below. In the embodiment
of FIGS. 4(a) and 4(b), color dots have opposite polarity with the
embedded polarity region within the color dot.
[0061] Second color component CC_2 of pixel design 410 has one
color dots CD_2_1. Color dots CD_2_1 is horizontally aligned with
drive component area DCA_2 and vertically separated from drive
component area DCA_2 by vertical dot spacing VDS1. Color dot CD_2_1
is vertically aligned with color CD_1_1 and horizontally separated
from color dot CD_1_1 by a horizontal dot spacing HDS1. Switching
element SE_2 is coupled to the electrodes of color dot CD_2_1 to
control the polarity of color dot CD_2_1. Color dot CD_2_1 includes
an embedded polarity region EPR_2_1_1.
[0062] Third color component CC_3 of pixel design 410 has one color
dots CD_3_1. Color dots CD_3_1 is horizontally aligned with drive
component area DCA_3 and vertically separated from drive component
area DCA_3 by vertical dot spacing VDS1. Color dot CD_3_1 is
vertically aligned with color CD_2_1 and horizontally separated
from color dot CD_2_1 by a horizontal dot spacing HDS1. Switching
element SE_3 is coupled to the electrodes of color dot CD_3_1 to
control the polarity of color dot CD_3_1. Color dot CD_3_1 includes
an embedded polarity region EPR_3_1_1.
[0063] The polarities of the color dots, embedded polarity regions,
and switching elements are shown using "+" and "-" signs. Thus, in
FIG. 4(a), which shows the positive dot polarity pattern of pixel
design 410+, switching elements SE_1 and SE_3; color dots CD_1_1
and CD_3_1, and embedded polarity region EPR_2_1_1 have positive
polarity. However, switching element SE_2; color dot CD_2_1, and
embedded polarity region 2 EPR_1_1_1 and EPR_3_1_1 have negative
polarity.
[0064] FIGS. 5(a) and 5(b) show portions of a color dot 500, having
a square shape electrode 510, with four square shaped embedded
polarity regions 512, 514, 516, and 518. FIG. 5(b) is a cross
sectional view of color dot 500 along the A1-A1' cut of FIG. 5(a).
As shown in FIG. 5(b), the embedded polarity regions of color dot
500 are created by changing the conductivity of electrode 510 in
the areas of embedded polarity regions. Specifically, changed
conductivity regions 517 and 519, which correspond to embedded
polarity regions 516 and 518, respectively, are formed in electrode
510. In one embodiment of the present invention, the changed
conductivity regions are heavily doped to reduce the conductivity
of the changed conductivity regions. In other embodiments of the
present invention, the embedded polarity regions can be formed by
etching portions of conductor 510 and filling the regions with a
less conductive material, such as electroactive polymers (such as
polyacetylene, polythiophene, polypyrrole (PPy), polyaniline
(PANI), and polystyrene), silicon-germanium and aluminum gallium
arsenide, or a non-conductive material, such as silicon dioxide.
Due to the different conductivity in the changed conductivity
regions, the electric fields in the embedded polarity regions
differ from the electric fields around the rest of electrode 510.
The interactions between the electric fields of the embedded
polarity regions and the rest of electrode 510 creates lateral
forces that can more quickly reorient the liquid crystals to their
proper position after a physical disturbance. In embodiments of the
present invention, that use non-conductive material for embedded
polarity regions, the embedded polarity regions would have a
neutral polarity.
[0065] FIG. 6(a)-6(c) show portions of a color dot 600, having a
square shape electrode 610, with an embedded polarity region 612,
having a circular base shape. FIG. 6(b) is a cross sectional view
of color dot 600 along the A1-A1' cut of FIG. 6(a). FIG. 6(c) is a
cross sectional view of color dot 700 along the B1-B1' cut of FIG.
6(a). As shown in FIG. 6(b), embedded polarity region 612 is
created by a field reduction layer 614, which reduces the electric
field from the portion of conductor 610 in embedded polarity region
612. Thus, the magnitude of the polarity within embedded polarity
region 612 differs from the rest of color dot 600. Depending on the
specific properties of field reduction layer 614, the magnitude of
the polarity in embedded polarity region 612 can be selectively
reduced. With complete reduction, the polarity of embedded polarity
region 612 can be set to neutral. A dielectric material,
passivation layer, or black matrix material, can be used as the
field reduction material in field reduction layer 614. As shown in
FIGS. 6(a), 6(b) and 6(c), field reduction layer 614 has a three
dimensional cylindrical shape.
[0066] However, in other embodiments of the present invention,
field reduction layer 614 can have a variety of three dimensional
shapes with varying combination of base shapes and sides. For
example, FIG. 7(a)-7(c) show portions of a color dot 700, having a
square shape electrode 710, with an embedded polarity region 712,
having a square base shape in accordance with one embodiment of the
present invention. FIG. 7(b) is a cross sectional view of color dot
700 along the A1-A1' cut of FIG. 7(a). FIG. 7(c) is a cross
sectional view of color dot 700 along the B1-B1' cut of FIG. 7(a).
As shown in FIGS. 7(b) and 7(c), field reduction layer 714 has
sloping sides which form a three-dimensional pyramidal shape.
[0067] FIG. 8(a)-8(c) show portions of a color dot 800, having a
square shape electrode 810, with an embedded polarity region 812,
having a circular base shape in accordance with one embodiment of
the present invention. FIG. 8(b) is a cross sectional view of color
dot 800 along the A1-A1' cut of FIG. 8(a). FIG. 8(c) is a cross
sectional view of color dot 800 along the B1-B1' cut of FIG. 8(a).
As shown in FIGS. 8(b) and 8(c), field reduction layer 814 has
sloping sides which form a three-dimensional cone shape.
[0068] FIG. 9(a)-9(c) show portions of a color dot 900, having a
square shape electrode 910, with an embedded polarity region 912,
having a circular base shape in accordance with one embodiment of
the present invention. FIG. 9(b) is a cross sectional view of color
dot 900 along the A1-A1' cut of FIG. 9(a). FIG. 9(c) is a cross
sectional view of color dot 900 along the B1-B1' cut of FIG. 9(a).
As shown in FIGS. 9(b) and 9(c), field reduction layer 914 has
curved sloping sides which form a three-dimensional rounded concave
shape, which could be an oblate spheroid or other ellipsoid.
[0069] FIG. 10(a)-10(c) show portions of a color dot 1000, having a
square shape electrode 1010, with an embedded polarity region 1012,
having a circular base shape in accordance with one embodiment of
the present invention. FIG. 10(b) is a cross sectional view of
color dot 1000 along the A1-A1' cut of FIG. 10(a). FIG. 10(c) is a
cross sectional view of color dot 1000 along the B1-B1' cut of FIG.
10(a). As shown in FIG. 10(b) along the A1-A1' cut, field reduction
layer has a triangular shape. However as shown in FIG. 10(c) along
the B1-B1' cut, field reduction layer 1014 has a rectangular shape.
Thus, field reduction layer 1014 has a three dimensional triangular
solid shape.
[0070] FIG. 11(a)-11(c) show portions of a color dot 1100, having a
square shape electrode 1110, with an embedded polarity region 1112,
having a circular base shape in accordance with one embodiment of
the present invention. FIG. 11(b) is a cross sectional view of
color dot 1100 along the A1-A1' cut of FIG. 11(a). FIG. 11(c) is a
cross sectional view of color dot 1100 along the B1-B1' cut of FIG.
11(a). As shown in FIGS. 11(b) and 11(c), field reduction layer
1114 has curved sloping sides which form a three-dimensional
rectangular solid having a rounded convex depression on top,
similar to a hyperboloid. Other embodiments of the present
invention may use other shapes for field reduction layers.
[0071] FIG. 12 illustrates another embodiment of the present
invention in which a field reduction layer 1214 is formed using an
insulating layer 1214_I on electrode 1210 and a conducting layer
1214_C on top of insulating layer 1214_I. Conducting layer 1214_C
reduces the electric field from electrode 1210 in embedded polarity
region 1212. Insulating layer 1214_I isolates conducting layer
1214_C from electrode 1210. A dielectric lateral layer or
passivation layer can be used to replace the insulating layer
1214_I, and to reduce the electric field. In another embodiment of
the present invention, conducting layer 1214_C is polarized. For
example, if electrode 1210 has positive polarity, conducting layer
1214_C is driven to a negative polarity. The interaction from the
fields of electrode 1210 and conducting layer 1214 creates lateral
forces that can more quickly reorient liquid crystals to their
proper position after a physical disturbance. In general, a black
matrix layer can be added to prevent the light leakage from the
field reduction layer 1214 or 1214_I. Various embodiments of the
present invention can have different shapes for conducting layer
1214_C. For example, conducting layer 1214_C could use any of the
shapes illustrated in FIGS. 6(a)-(c) to 11(a)-(c) as well as other
shapes.
[0072] In other embodiment of the present invention, the embedded
polarity regions are induced from below the conductor to allow
greater uniformity of the interface between the electrodes and the
liquid crystal medium. FIGS. 13(a) and 13(b) illustrate a color dot
1300 in accordance with another embodiment of the present
invention. Color dot 1300 includes a square shaped electrode 1310
with a square shaped embedded polarity region 1312. FIG. 13(b) is a
cross sectional view of color dot 1300 along the A1-A1' cut of FIG.
13(a). As shown in FIG. 13(b), embedded polarity region 1312 is
created by an embedded electrode 1316 underneath electrode 1310.
Embedded electrode 1316 is separated from electrode 1310 by an
insulating layer 1314. Embedded electrode 1316 is electrified to
generate an electric field through electrode 1310. In most
embodiments of the present invention electrode 1310 and embedded
electrode 1316 have opposite polarity directions. For example, when
electrode 1310 has positive polarity, embedded electrode 1316 would
have a negative polarity. The interaction of the electric field
generated by electrode 1310 and embedded electrode 1316 creates
lateral forces that can more quickly reorient liquid crystals to
their proper position after a physical disturbance.
[0073] As shown in FIG. 13(c), the techniques to create embedded
polarity regions can be combined. Specifically, in FIG. 13(c), a
changed conductive region 1318 is created in electrode 1310 within
embedded polarity region 1312. In the embodiment of FIG. 13(c),
changed conductive region 1318 is made non-conductive so that the
electric field in embedded polarity region 1312 is predominantly
controlled by embedded electrode 1316. The interaction of the
electric field generated by electrode 1310 and embedded electrode
1316 creates lateral forces that can more quickly reorient liquid
crystals to their proper position after a physical disturbance.
[0074] FIGS. 14(a)-14(b) illustrate portions of a color dot 1400 in
accordance with another embodiment of the present invention. Color
dot 1400 includes a square shaped electrode 1410 with a square
shaped embedded polarity region 1412. However, electrode 1410 does
not extend into embedded polarity region 1412. In the embodiment of
FIG. 14(a), electrode 1410 is etched to create a void in embedded
polarity region 1412. In other embodiments of the present
invention, electrodes are formed with the voids.
[0075] FIG. 14(b) is a cross sectional view of color dot 1400 along
the A1-A1' cut of FIG. 14(a). As shown in FIG. 14(b), embedded
polarity region 1412 is created by an embedded electrode 1416
underneath electrode 1410. Embedded electrode 1416 is separated
from electrode 1410 by an insulating layer 1414. In the embodiment
of FIG. 14(b) insulating layer 1414 is etched to create a void in
embedded polarity region 1410. In other embodiments, of the present
invention, insulating layer 1414 does not include voids. Embedded
electrode 1416 is electrified to generate an electric field through
the void in electrode 1410. In most embodiments of the present
invention electrode 1410 and embedded electrode 1416 have opposite
polarity directions. For example, when electrode 1410 has positive
polarity, embedded electrode 1416 would have a negative polarity.
The interaction of the electric field generated by electrode 1410
and embedded electrode 1416 creates lateral forces that can more
quickly reorient liquid crystals to their proper position after a
physical disturbance.
[0076] As explained above, multiple domains can be created using
intrinsic fringe fields. However, intrinsic fringe fields are only
applicable on small color dots. Thus, for larger displays pixels
are created with color components having many color dots. Each
color component is controlled by a separate switching element such
as a thin-film transistor (TFT). Generally, the color components
are red, green, and blue. In accordance with the present invention,
the color components of a pixel are further divided into color
dots. FIG. 15(a) illustrates a pixel design using multiple color
dots per color component and embedded polarity regions in
accordance with one embodiment of the present invention.
Specifically, FIG. 15(a) shows a pixel design 1500 which includes
three color components. Each of the three color components is
further divided into three color dots. For clarity, the color dots
are referenced as CD_X_Y, where X is a color component (from 1 to
3) and Y is a dot number (from 1 to 3). Specifically, pixel 1500 is
a pixel formed by nine color dots. Each of the color dots include
an embedded polarity region at the center of the color dot. The
embedded polarity region of a color dot CD_X_Y is labeled
EPR_X_Y.
[0077] Color dots CD_1_1 (i.e., the first color dot of color
component 1), CD_2_1 (i.e., the first color dot of the second color
component), and CD_3_1 (i.e., the first color dot of the third
color component) form the first row of pixel design 1500. Color
dots CD_1_2, CD_2_2, and CD_3_2 form a second row of pixel design
1500. However the second row is offset from the first row so that
color dot CD_1_2 is adjacent to color dot CD_2_1. Color dots
CD_1_3, CD_2_3, and CD_3_3 form the third row of pixel design 1500.
However the third row is aligned with the first row so that color
dot CD_2_3 is adjacent to color dot CD_1_2.
[0078] The color dots of a color component are controlled by a
switching element, such as a thin-film transistor (TFT), thus the
polarity of all the color dots of one color components are the
same. Various designs can be used to make the electrical
connections between the color dots of a color component. For
example, some embodiments of the present invention use ITO
connections, which are optically transparent, from the switching
element to the color dots. FIG. 15(b) shows a perspective view of a
portion of an LCD 1501 with pixel 1502 of pixel design 1500.
Specifically, FIG. 15(b) shows a polarizer 1503 attached to a
substrate 1505. Electrodes E11, E12, E13, E21, E22, E23, E31, E32,
and E33 of pixel 1502 are formed on the top surface of substrate
1505. Various electrodes (E) of other pixels are also formed on
substrate 1505. The electrodes include an embedded polarity region
(shaded square within each electrode) that can be formed using the
various methods discussed above. Due to space constraints the
embedded polarity regions are not specifically labeled in FIG.
15(b). For clarity, the electrodes E of other pixels are shown with
dotted lines. An alignment layer (not shown) would cover the
electrodes. Also shown in FIG. 15(b) are transistors T1, T2, and T3
of Pixel 1502. For clarity the transistors of other pixels are not
shown in FIG. 15(b).
[0079] Electrodes E11, E12, E13, E21, E22, E23, E31, E32, and E33
correspond with color dots CD_1_1, CD_1_2, CD_1_3, CD_2_1, CD_2_2,
CD_2_3, CD_3_1, CD_3_2, and CD_3_3 respectively. As explained above
color dots CD_1_1, CD_1_2, and CD_1_3 are electrically connected
and electrically controlled and switched by a single switching
element such as a thin-film transistor, which is located at color
dot CD_1_1. Thus as shown in FIG. 15(b), transistor T1 is coupled
to electrode E11 and electrodes E11, E12, and E13 are electrically
connected by connectors 1511 and 1512. Connectors 1511 and 1512 are
usually formed of a transparent conductive material such as ITO. As
explained above, the polarity of the embedded polarity region
differs from that of the color dot. Thus, the polarity of the
embedded polarity regions EPR_1_1, EPR_1_2, and EPR_1_3 (not
labeled in FIG. 15(b) are controlled by a polarity source different
from transistor T1 (which controls the polarity of color dots
CD_1_1, CD_1_2, and CD_1_3). For example in one embodiment of the
present invention, embedded polarity regions EPR_1_1, EPR_1_2, and
EPR_1_3 (not labeled in FIG. 15(b) are coupled to electrodes E21,
E22, and E23, respectively.
[0080] Color dots CD_2_1, CD_2_2, and CD_2_3 are electrically
connected and electrically controlled and switched by a single
switching element, which is located at color dot CD_2_1. Thus as
shown in FIG. 15(b), transistor T2 is coupled to electrode E21 and
electrodes E21, E22, and E23 are electrically connected by
connectors 1521 and 1522. Likewise, Color dots CD_3_1, CD_3_2, and
CD_3_3 are electrically connected and electrically controlled and
switched by a single switching element, which is located at color
dot CD_3_1. Thus as shown in FIG. 15(b), transistor T3 is coupled
to electrode E31 and electrodes E31, E32, and E33 are electrically
connected by connectors 1531 and 1532.
[0081] To achieve multiple domains, the first and third color
components of a pixel have the same polarity and the second
component has the opposite polarity. However for adjacent pixels
the polarities are reversed. For MVALCDs using the pixel design of
FIG. 15, two different dot polarity patterns are used for the
pixels. FIGS. 15(c) and 15(d) illustrate the two dot polarity
patterns. In FIG. 15(c), a pixel 1510 using pixel design 1500 is an
example of the first dot polarity pattern, which has positive
polarity at the second color component, i.e., color dots CD_2_1,
CD_2_2, and CD_2_3, and negative polarity at the first and third
color components, i.e., CD_1_1, CD_1_2, CD_1_3, CD_3_1, CD_3_2, and
CD_3_3. As explained above, the polarity of the embedded polarity
region differs from that of the color dot containing the embedded
polarity region. Thus, the polarity of the embedded polarity
regions are controlled by a polarity source different from the
source controlling the polarity of color dots containing the
embedded polarity regions.
[0082] In FIG. 15(d), pixel 1520 is an example of the second dot
polarity pattern, which has negative polarity at the second color
component, i.e., color dots CD_2_1, CD_2_2, and CD_2_3, and
positive polarity at the first and third color components, i.e.,
CD_1_1, CD_1_2, CD_1_3, CD_3_1, CD_3_2, and CD_3_3. As explained
above, the polarity of the embedded polarity region differs from
that of the color dot containing the embedded polarity region. In
actual operation a pixel will switch between the first dot polarity
pattern and the dot second polarity pattern between each image
frame. For clarity, the dot polarity pattern, in which the first
color dot of the first color component has a positive polarity, is
referred to as the positive dot polarity pattern. Conversely, the
dot polarity pattern in which the first color dot of the first
color component has a negative polarity is referred to as the
negative dot polarity pattern. Thus, FIG. 15(c) is the negative dot
polarity pattern and FIG. 15(d) is the positive dot polarity
pattern for the pixel design of FIG. 15(a).
[0083] Pixels using the pixel design of FIG. 15(a) can be arranged
in a checkerboard pattern with half the pixels having the positive
dot polarity pattern and half the pixels having the negative dot
polarity pattern. FIG. 15(e) illustrates the checkerboard pattern
with pixels P(0, 0), P(1, 0), P(2, 0), P(0, 1), P(1, 1), and P(2,
1). Specifically, as illustrated in FIG. 5(c), a pixel P(x, y) is
in the xth column (from the left and the y-th row starting from the
bottom, with pixel P(0, 0) being the bottom left corner. Pixels
P(0, 0), P(2, 0) and P(1, 1) have the positive dot polarity pattern
and pixels P(1, 0), P(0, 1), and P(2, 1) have the negative dot
polarity pattern. Thus, in general a pixel P(x, y) has the negative
dot polarity pattern if x plus y is an odd number. Conversely,
pixel P(x, y) has the positive dot polarity pattern if x plus y is
an even number. However, at the next frame the pixels will switch
dot polarity patterns. Thus, a MVALCD using the pixel design of
FIG. 15(a) has a first set of pixels having a first dot polarity
pattern and a second set of pixels having a second dot polarity
pattern. The first set of pixels and the second set of pixels are
arranged in a checkerboard pattern.
[0084] A close examination of FIG. 15(e) reveals that the color
dots also have a checkerboard pattern in terms of polarity. Thus,
for each color dot of a first polarity, the four adjacent color
dots will be of a second polarity. For example, color dot CD_3_1 of
pixel P(0, 0), which has a positive polarity, is surrounded by four
color dots of negative polarity. Specifically, color dots CD_3_3 of
pixel P(0, 1), color dot CD_1_1, of pixel P(1, 0), and color dots
CD_2_1 and CD_2_2 of pixel P(0, 0). As explained above, polarity
inversion between neighboring color dots enhances the fringe field
of the color dots. Because the color dots are quite small, fringe
fields from the color dots will cause multiple domains in the
liquid crystals of each color dot under the principles explained
above with respect to FIGS. 3(a) and 3(b).
[0085] FIG. 16(a)-16(b) shows another pixel design having multiple
color dots per color component that incorporate embedded polarity
regions in accordance with the present invention. Specifically,
FIGS. 16(a) and 16(b) show different dot polarity patterns of a
pixel design 1610 (labeled 1610+ and 1610- as described below) that
is often used in displays having a switching element row inversion
driving scheme. In actual operation a pixel will switch between a
first dot polarity pattern and a second dot polarity pattern
between each image frame. For clarity, the dot polarity pattern, in
which the first color dot of the first color component has a
positive polarity, is referred to as the positive dot polarity
pattern. Conversely, the dot polarity pattern in which the first
color dot of the first color component has a negative polarity is
referred to as the negative dot polarity pattern. Specifically, in
FIG. 16(a), pixel design 1610 has a positive dot polarity pattern
(and is thus labeled 1610+) and in FIG. 16(b), pixel design 1610
has a negative dot polarity pattern (and is thus labeled 1610-).
Furthermore, the polarity of each polarized component in the
various pixel designs are indicated with "+" for positive polarity
or "-" for negative polarity.
[0086] Pixel design 1610 has three color components CC_1, CC_2 and
CC_3 (not labeled in FIGS. 16(a)-16(b)). Each of the three color
components includes two color dots. For clarity, the color dots are
referenced as CD_X_Y, where X is a color component (from 1 to 3 in
FIGS. 16(a)-16(b)) and Y is a dot number (from 1 to 2 in FIGS.
16(a)-16(b)). Pixel design 1610 also includes a switching element
for each color component (referenced as SE_1, SE_2, and SE_3) and a
fringe field amplifying region for each color component (referenced
as FFAR_1, FFAR_2, and FFAR_3). Switching elements SE_1, SE_2, and
SE_3 are arranged in a row. Device component areas around each
switching element are covered by the fringe field amplifying
regions and are thus not specifically labeled in FIGS. 16(a) and
16(b). Fringe field amplifying regions FFAR_1, FFAR_2, and FFAR_3
are also arranged in a row and described in more detail in FIG.
16(c).
[0087] First color component CC_1 of pixel design 1610 has two
color dots CD_1_1 and CD_1_2. Color dots CD_1_1 and CD_1_2 form a
column and are separated by a vertical dot pacing VDS1. In other
words, color dots CD_1_1 and CD_1_2 are horizontally aligned and
vertically separated by vertical dot spacing VDS1. Furthermore,
color dots CD_1_1 and CD_1_2 are vertically offset by vertical dot
offset VDO1 which is equal to vertical dot spacing VDS1 plus the
color dot height CDH. Switching element SE_1 is located in between
color dots CD_1_1 and CD_1_2 so that color dot CD_1_1 is on a first
side of the row of switching elements and color dot CD_1_2 is on a
second side of the row of switching elements. Switching element
SE_1 is coupled to the electrodes of color dots CD_1_1 and CD_1_2
to control the voltage polarity and voltage magnitude of color dots
CD_1_1 and CD_1_2.
[0088] Each color dot of color component CD_1_1 includes an
embedded polarity region which would minimize any touch mura
effects in the color dot. Specifically, color dots CD_1_1 and
CD_1_2 include embedded polarity regions EPR_1_1 and EPR_1_2,
respectively. As shown in FIG. 16(a), embedded polarity regions
EPR_1_1 and EPR_1_2 are centered within color dots CD_1_1 and
CD_1_2, respectively. Any of the various techniques used to form
embedded polarity regions described herein can be used with pixel
design 1610. In a particular embodiment of the present invention,
the techniques illustrated in FIGS. 14(a)-(b) are used. However,
other embodiments of the present invention can use other techniques
to form embedded polarity regions, can include multiple embedded
polarity regions, or can offset the embedded polarity region.
[0089] As explained above, the polarity of the embedded polarity
region differs from that of the color dot. Thus, the polarity of
the embedded polarity regions EPR_1_1 and EPR_1_2 are controlled by
a polarity source different from switching element SE_1 (which
controls the polarity of color dots CD_1_1 and CD_1_2). In some
embodiments of the present invention, a display includes dedicated
embedded-polarity-region switching elements to control the polarity
of the embedded polarity regions (See FIG. 16(d) for one such
embodiment). Other embodiments of the present invention, may couple
the embedded polarity regions to other elements of the pixel that
have a differing polarity. For example, in some embodiments of the
present invention, embedded polarity regions CD_1_1 and CD_1_2 are
coupled to fringe field amplifying region FFAR_1, which is
described below.
[0090] Similarly, second color component CC_2 of pixel design 410
has two color dots CD_2_1 and CD_2_2. Color dots CD_2_1 and CD_2_2
form a second column and are separated by a vertical dot spacing
VDS1. Thus, color dots CD_2_1 and CD_2_2 are horizontally aligned
and vertically separated by vertical dot spacing VDS1. Switching
element SE_2 is located in between color dots CD_2_1 and CD_2_2 so
that color dot CD_2_1 is on the first side of the row of switching
elements and color dot CD_2_2 is on a second side of the row of
switching elements. Switching element SE_2 is coupled to the
electrodes of color dots CD_2_1 and CD_2_2 to control the voltage
polarity and voltage magnitude of color dots CD_2_1 and CD_2_2.
Second color component CC_2 is vertically aligned with first color
component CC_1 and separated from color component CC_1 by a
horizontal dot spacing HDS1, thus color components CC_2 and CC_1
are horizontally offset by a horizontal dot offset HDO1, which is
equal to horizontal dot spacing HDS1 plus the color dot width CDW.
Specifically with regards to the color dots, color dot CD_2_1 is
vertically aligned with color dots CD_1_1 and horizontally
separated by horizontal dot spacing HDS1. Similarly, color dot
CD_2_2 is vertically aligned with color dots CD_2_1 and
horizontally separated by horizontal dot spacing HDS1. Thus color
dot CD_1_1 and color dot CD_2_1 form a first row of color dots and
color dot CD_1_2 and color dot CD_2_2 form a second row of color
dots. Like color dots CD_1_1 and CD_1_2, Color dots CD_2_1 and
CD_2_2 include embedded polarity regions EPR_2_1 and EPR_2_2,
respectively.
[0091] Similarly, third color component CC_3 of pixel design 410
has two color dots CD_3_1 and CD_3_2. Color dots CD_3_1 and CD_3_2
form a third column and are separated by a vertical dot spacing
VDS1. Thus, color dots CD_3_1 and CD_3_2 are horizontally aligned
and vertically separated by vertical dot spacing VDS1. Switching
element SE_3 is located in between color dots CD_3_1 and CD_3_2 so
that color dot CD_3_1 is on the first side of the row of switching
elements and color dot CD_3_2 is on a second side of the row of
switching elements. Switching element SE_3 is coupled to the
electrodes of color dots CD_3_1 and CD_3_2 to control the voltage
polarity and voltage magnitude of color dots CD_3_1 and CD_3_2.
Third color component CC_3 is vertically aligned with second color
component CC_2 and separated from color component CC_2 by
horizontal dot spacing HDS1, thus color components CC_3 and CC_2
are horizontally offset by a horizontal dot offset HDO1.
Specifically with regards to the color dots, color dot CD_3_1 is
vertically aligned with color dots CD_2_1 and horizontally
separated by horizontal dot spacing HDS1. Similarly, color dot
CD_3_2 is vertically aligned with color dots CD_2_2 and
horizontally separated by horizontal dot spacing HDS1. Thus color
dot CD_3_1 is on the first row of color dots and color dot CD_3_2
is on the second row of color dots. Like color dots CD_1_1 and
CD_1_2, Color dots CD_3_1 and CD_3_2 include embedded polarity
regions EPR_3_1 and EPR_3_2, respectively.
[0092] For clarity, the color dots of pixel design 1610 are
illustrated with color dots having the same color dot height CDH.
However, some embodiments of the present invention may have color
dots with different color dot heights. For example in one
embodiment of the present invention that is a variant of pixel
design 1610, color dots CD_1_1, CD_2_1 and CD_3_1 have a smaller
color dot height than color dots CD_1_2, CD_2_2, and CD_3_2.
[0093] Pixel design 1610 also includes fringe field amplifying
regions FFAR_1, FFAR_2, and FFAR_3. FIG. 16(c) shows a more
detailed view of fringe field amplifying region FFAR_1 of pixel
design 1610. For clarity fringe field amplifying regions FFAR_1 is
conceptually divided into a vertical amplifying portion VAP and a
horizontal amplifying portion HAP. In FIG. 16(c) horizontal
amplifying portion HAP is vertically centered on and extends to the
left of vertical amplifying portion VAP. Use of horizontal
amplifying portions and vertical amplifying portions allows clearer
description of the placement of fringe field amplifying region
FFAR1. In most embodiments of the present invention, the electrodes
of the fringe field amplifying regions are formed by one contiguous
conductor. Horizontal amplifying portion HAP has a horizontal
amplifying portion width HAP_W and a horizontal amplifying portion
height HAP_H. Similarly, vertical amplifying portion VAP has a
vertical amplifying portion width VAP_W and a vertical amplifying
portion height HAP_H. Fringe field amplifying regions FFAR_2 and
FFAR_3 have the same shape as fringe field amplifying region
FFAR_1. In embodiments of the present invention having different
sized color dots, horizontal amplifying region HAP would be located
in between the color dots rather than centered on vertical
amplifying portion VAP.
[0094] As shown in FIG. 16(a), fringe field amplifying regions
FFAR_1, FFAR_2, and FFAR_3 are placed in between the color dots of
pixel design 1610. Specifically, fringe field amplifying region
FFAR_1 is placed so that the horizontal amplifying portion of
fringe field amplifying region FFAR_1 lies in between color dots
CD_1_1 and CD_1_2 and is separated from color dots CD_1_1 and
CD_1_2 by a vertical fringe field amplifying region spacing VFFARS.
The vertical amplifying portion of fringe field amplifying region
FFAR_1 is placed to the right of color dots CD_1_1 and CD_1_2 and
is separated from color dots CD_1_1 and CD_1_2 by a horizontal
fringe field amplifying region spacing HFFARS. Thus, fringe field
amplifying region FFAR_1 extends along the bottom and the right
side of color dot CD_1_1 and along the top and right side of color
dot CD_1_2. Furthermore, this placement also causes the vertical
amplifying portion of fringe field amplifying region FFAR_1 to be
in between color dots CD_1_1 and CD_2_1 and in between color dots
CD_1_2 and CD_2_2.
[0095] Similarly, fringe field amplifying region FFAR_2 is placed
so that the horizontal amplifying portion of fringe field
amplifying region FFAR_2 lies in between color dots CD_2_1 and
CD_2_2 and is separated from color dots CD_2_1 and CD_2_2 by a
vertical fringe field amplifying region spacing VFFARS. The
vertical amplifying portion of fringe field amplifying region
FFAR_2 is placed to the right of color dots CD_2_1 and CD_2_2 and
is separated from color dots CD_2_1 and CD_2_2 by a horizontal
fringe field amplifying region spacing HFFARS. Thus, fringe field
amplifying region FFAR_1 extends along the bottom and the right
side of color dot CD_2_1 and along the top and right side of color
dot CD_2_2. This placement also causes the vertical amplifying
portion of fringe field amplifying region FFAR_2 to be in between
color dots CD_2_1 and CD_3_1 and in between color dots CD_2_2 and
CD_3_2.
[0096] Fringe field amplifying region FFAR_3 is placed so that the
horizontal amplifying portion of fringe field amplifying region
FFAR_3 lies in between color dots CD_3_1 and CD_3_2 and is
separated from color dots CD_3_1 and CD_3_2 by a vertical fringe
field amplifying region spacing VFFARS. The vertical amplifying
portion of fringe field amplifying region FFAR_3 is placed to the
right of color dots CD_3_1 and CD_3_2 and is separated from color
dots CD_3_1 and CD_3_2 by a horizontal fringe field amplifying
region spacing HFFARS. Thus, fringe field amplifying region FFAR_3
extends along the bottom and the right side of color dot CD_3_1 and
along the top and right side of color dot CD_3_2.
[0097] The polarities of the color dots, fringe field amplifying
regions, and switching elements are shown using "+" and "-" signs.
Thus, in FIG. 16(a), which shows the positive dot polarity pattern
of pixel design 1610+, all the switching elements (i.e. switching
elements SE_1, SE_2, and SE_3); all the color dots (i.e. color dots
CD_1_1, CD_1_2, CD_2_1, CD_2_2, CD_3_1, and 3_2) have positive
polarity. However, all the fringe field amplifying regions (i.e.
fringe field amplifying regions FFAR_1, FFAR_2, and FFAR_3) have
negative polarity. As explained above, Embedded polarity regions
may have the same direction of polarity (i.e. positive or negative)
as the color dot but have a different magnitude of polarity.
Alternatively, embedded polarity regions may have different
polarity (i.e. "direction of polarity") than the color dot (e.g.
positive polarity for color dot polarity with negative polarity for
embedded polarity regions). In addition, embedded polarity regions
can have neutral polarity. In a particular embodiment of the
present invention, the embedded polarity regions of pixel design
1610 have different polarity than the color dots. Thus for this
embodiment, embedded polarity regions EPR_1_1, EPR_1_2, EPR_2_1,
EPR_2_2, EPR_3_1, and EPR_3_2 would have negative polarity in FIG.
16(a).
[0098] FIG. 16(b) shows pixel design 1610 with the negative dot
polarity pattern. For the negative dot polarity pattern, all the
switching elements (i.e. switching elements SE_1, SE_2, and SE_3)
and all the color dots (i.e. color dots CD_1_1, CD_1_2, CD_2_1,
CD_2_2, CD_3_1, and 3_2) have negative polarity. However, all the
fringe field amplifying regions (i.e. fringe field amplifying
regions FFAR_1, FFAR_2, and FFAR_3) have positive polarity. In the
particular embodiment of the present invention in which the
embedded polarity regions of pixel design 1610 has different
polarity than the color dots, embedded polarity regions EPR_1_1,
EPR_1_2, EPR_2_1, EPR_2_2, EPR_3_1, and EPR_3_2 would have positive
polarity in FIG. 16(b).
[0099] Fringe fields in each of the color dots are amplified if
adjacent components have opposite polarities. Pixel design 1610
makes use of the fringe field amplifying regions to enhance and
stabilize the formation of multiple domain in the liquid crystal
structure. In general, the polarities of the polarized components
are assigned so that a color dot of a first polarity has
neighboring polarized components of the second polarity. For
example for the positive dot polarity pattern of pixel design 1610
(FIG. 16(a)), color dot CD_2_2 has positive polarity. However the
neighboring polarized components (fringe field amplifying regions
FFAR_2 and FFAR_1) have negative polarity. Thus, the fringe field
of color dot CD_2_2 is amplified. Furthermore, as explained below,
the polarity reversing scheme is carried out at the display level
as well so that the color dot of another pixel that is placed next
to color dot CD_1_2 would have negative polarity (see FIG.
16(d)).
[0100] Because, all the switching elements in pixel design 1610
have the same polarity and the fringe field amplifying regions
require the opposite polarity, the fringe field amplifying regions
are driven by an external polarity source, i.e. a polarity source
from outside the specific pixel of pixel design 1610. Various
sources of opposite polarity can be used in accordance with
differing embodiments of the present invention. For example
specific fringe field amplifying region switching elements may be
used or switching elements of nearby pixels having an opposite dot
polarity could also used to drive the fringe field amplifying
regions. In the embodiments of FIGS. 16(a)-16(b), switching
elements of nearby pixels having an opposite dot polarity could
also used to drive the fringe field amplifying regions. Therefore,
pixel design 1610 includes conductor to facilitate coupling the
fringe field amplifying regions to switching elements in other
pixels. Specifically, a conductor 1612 of a current pixel would
couple the electrode of fringe field amplifying region FFAR_1 to
switching element SE_1 (see FIGS. 16(d) and 16(e)) of a pixel above
the current pixel. The connection to the switching element would be
via the electrodes of the color dots of the pixel above the current
pixel. Similarly, a conductor 1614 of a current pixel would couple
the electrode of fringe field amplifying region FFAR_2 to switching
element SE_2 (see FIGS. 16(d)) of a pixel above the current pixel.
The connection to the switching element would be via the electrodes
of the color dots of the pixel above the current pixel. A conductor
1616 of a current pixel would couple the electrode of fringe field
amplifying region FFAR_3 to switching element SE_3 (see FIGS. 16(d)
and 16(e)) of a pixel above the current pixel. The connection to
the switching element would be via the electrodes of the color dots
of the pixel above the current pixel.
[0101] These connections are better shown in FIG. 16(d), which
shows a portion of display 1620 using pixels P(0, 0), P(1, 0), P(0,
1), and P(1, 1) of pixel design 1610 with a switching element row
inversion driving scheme. Display 1620 could have thousands of rows
with thousand of pixels on each row. The rows and columns would
continue from the portion shown in FIG. 16(d) in the manner shown
in FIG. 16(d). For clarity, the gate lines and source lines that
control the switching elements are omitted in FIG. 16(d).
Furthermore, to better illustrate each pixel, the area of each
pixel is shaded; this shading is only for illustrative purposes in
FIG. 16(d) and has no functional significance. The pixels of
display 1620 are arranged so that all pixels in a row have the same
dot polarity pattern (positive or negative) and each successive row
should alternate between positive and negative dot polarity
pattern. Thus, pixels P(0, 0) and P(1, 0) in the first row (i.e.
row 0) have positive dot polarity pattern and pixels P(0, 1) and
P(1, 1) in the second row (i.e. row 1) have the negative dot
polarity pattern. However, at the next frame the pixels will switch
dot polarity patterns. Thus in general a pixel P(x, y) has a first
dot polarity pattern when y is even and a second dot polarity
pattern when y is odd. Internal conductors 1612, 1614, and 1616 in
pixel design 1610, provide polarity to the fringe field amplifying
regions. Specifically, fringe field amplifying regions of a first
pixel receive voltage polarity and voltage magnitude from a second
pixel. Specifically, the second pixel is the pixel above the first
pixel. For example, the electrodes of fringe field amplifying
region FFAR_1 of pixel P(0, 0) is coupled to switching elements
SE_1 of pixel P(0, 1) via the electrodes of color dots CD_1_2 of
pixel P(0, 1). Similarly, the electrodes of fringe field amplifying
regions FFAR_2 and FFAR_3 of pixel P(0, 0) are coupled to switching
elements SE_2, and SE_3 of pixel P(0, 1) via color dots CD_2_2, and
CD_3_2 of pixel P(0, 1), respectively.
[0102] Display 1620 also includes embedded-polarity-region
switching elements EPR_SE_X_Y, for each row of embedded polarity
regions. In FIG. 16(d), "X" represents the row number of the pixel,
and "Y" represents the row number of embedded polarity regions
within a pixel. Thus, embedded-polarity-region switching elements
EPR_SE_0_1 and EPR_SE_0_2 are used for the pixels in row 0 (i.e.
pixel P(0, 0) and pixel P(1, 0)). Specifically,
embedded-polarity-region switching element EPR_SE_0_1 is coupled to
embedded polarity regions EPR_1_1, EPR_2_1, and EPR_3_1 of pixel
P(0, 0) and to embedded polarity regions EPR_1_1, EPR_2_1, and
EPR_3_1 of pixel P(1, 0). Embedded-polarity-region switching
element EPR_SE_0_2 is coupled to embedded polarity regions EPR_1_2,
EPR_2_2, and EPR_3_2 of pixel P(0, 0) and to embedded polarity
regions EPR_1_2, EPR_2_2, and EPR_3_2 of pixel P(1, 0). Likewise,
embedded-polarity-region switching elements EPR_SE_1_1 and
EPR_SE_1_2 are used for the pixels in row 1 (i.e. pixel P(0, 1) and
pixel P(1, 1)). Specifically, embedded-polarity-region switching
element EPR_SE_1_1 is coupled to embedded polarity regions EPR_1_1,
EPR_2_1, and EPR_3_1 of pixel P(0, 1) and to embedded polarity
regions EPR_1_1, EPR_2_1, and EPR_3_1 of pixel P(1, 1).
Embedded-polarity-region switching element EPR_SE_1_2 is coupled to
embedded polarity regions EPR_1_2, EPR_2_2, and EPR_3_2 of pixel
P(0, 1) and to embedded polarity regions EPR_1_2, EPR_2_2, and
EPR_3_2 of pixel P(1, 1). Generally, an embedded-polarity-region
switching element would have different polarity as compared to the
switching elements in the pixel corresponding to the
embedded-polarity-region switching element. Thus, in FIG. 16(d),
embedded-polarity-region switching elements EPR_SE_0_1 and
EPR_SE_0_2 would have negative polarity. Conversely,
embedded-polarity-region switching elements EPR_SE_1_1 and
EPR_SE_1_2 would have positive polarity. In some embodiments of the
present invention, the embedded-polarity-region switching elements
would be placed in a more balanced manner. For example, in a
particular embodiment of the present invention, half of the
embedded-polarity-region switching elements are placed on the right
side of the display and half of the embedded-polarity-region
switching elements are placed on the left side of the display.
[0103] Due to the switching of polarities on each row in display
1620, if a color dot has the first polarity, any neighboring
polarized components and embedded polarity regions would have the
second polarity. For example, color dot CD_3_2 of pixel P(0, 1) has
negative polarity while, embedded polarity region EPR_3_2 of pixel
P(0, 1), color dot CD_3_1 of pixel P(0, 0), fringe field amplifying
regions FFAR_2 and FFAR_3 of pixel P(0, 1) have positive polarity.
In a particular embodiment of the present invention, each color dot
has a width of 40 micrometers and a height of 60 micrometers. Each
embedded polarity region has a width of 10 micrometers and a height
of 10 micrometers Each fringe field amplifying region has a
vertical amplifying portion width of 5 micrometers, a vertical
amplifying portion height of 145 micrometers, a horizontal
amplifying portion width of 50 micrometers, a horizontal amplifying
height of 5 micrometers. Horizontal dot spacing HDS1 is 15
micrometers, vertical dot spacing VDS1 is 25 micrometers,
horizontal fringe field amplifying spacing HFFARS is 5 micrometers,
and vertical fringe field amplifying spacing VFFARS is 5
micrometers.
[0104] In another embodiment of the present invention, embedded
polarity regions are polarized using switching elements of nearby
pixels rather than having dedicated embedded polarity switching
elements. FIG. 16(e) shows a portion of a display 1630 using pixels
P(0, 0), P(1, 0), P(0, 1), and P(1, 1) of pixel design 1610 with a
switching element row inversion driving scheme. Display 1630 could
have thousands of rows with thousand of pixels on each row. The
rows and columns would continue from the portion shown in FIG.
16(e) in the manner shown in FIG. 16(e). For clarity, the gate
lines and source lines that control the switching elements are
omitted in FIG. 16(e). Furthermore, to better illustrate each
pixel, the area of each pixel is shaded; this shading is only for
illustrative purposes in FIG. 16(e) and has no functional
significance. Due to space limitations color dots are labeled as
CDXY as opposed to CD_X_Y and embedded polarity regions are labeled
as EPRXY as opposed to EPR_X_Y.
[0105] Because display 1630 and display 1620 are very similar only
the differences are described in detail. For example, the pixels of
display 1630 are arranged in the same manner as the pixels of
display 1620. Furthermore, the polarity of the color dots,
switching elements and fringe field amplifying regions are the
same. Thus like in display 1620, a pixel P(x, y) in display 1630
also has a first dot polarity pattern when y is even and a second
dot polarity pattern when y is odd. The primary difference between
display 1620 and display 1630 is that the polarity for the embedded
polarized regions in display 1630 is provided from the switching
elements of nearby pixels rather than from dedicated embedded
polarity switching elements which were used in display 1620.
[0106] In display 1630, a first pixel is paired with a second
pixel, so that the embedded polarity regions of the first pixel is
coupled to the switching element of the second pixel and the
embedded polarity regions of the second pixel is coupled to the
switching elements of the first pixel. Specifically, pixels on even
numbered rows are paired with the pixel in the odd numbered row
above the even numbered row. Thus in FIG. 16(e), pixel P(0, 0) is
paired with Pixel P(0, 1) and pixel P(1, 0) is paired with pixel
P(1, 1). In general, a pixel P(X, Y) is paired with a pixel P(X,
Y+1) if Y is even. Conversely, a pixel P(x, Y) is paired with pixel
P(X, Y-1) if Y is odd.
[0107] As illustrated in FIG. 16(e), in display 1630 each embedded
polarity regions is coupled to a switching element of paired pixel
by a conductor C_I_J_X_Y (labeled with CIJXY in FIG. 16(e) due to
space constraints), where I, J denotes the pixel (e.g. pixel P(I,
J) containing the embedded polarity region, X is the color
component, and Y denotes the color dot (e.g. color dot CD_X_Y
(shortened in FIG. 16(e) as CDXY)) within the pixel. For example,
conductor C0112 couples embedded polarity region EPR12 of pixel
P(0, 1) to switching element SE_1 of pixel P(0, 0). The conductors
for the embedded polarity regions are shown with dashed lines to
indicate that the conductors are in a different plane from the
color dots. Typically, the color dots are formed with ITO in a
first plane and the conductors are formed with a metal layer in a
second plane.
[0108] As explained above in pixels on odd numbered rows, embedded
polarity elements of a first pixel are coupled to switching
elements of the pixel below the first pixel. For example, embedded
polarity region EPR_2_2 (labeled EPR22 in FIG. 16(e)) of pixel P(0,
1) is coupled to switching element SE_2 of pixel P(0, 0) by
conductor C_0_1_2_2 (labeled C0122 in FIG. 16(e)). Similarly,
embedded polarity region EPR_2_1 (labeled EPR21 in FIG. 16(e)) of
pixel P(0, 1) is coupled to switching element SE_2 of pixel P(0, 0)
by conductor C_0_1_2_1 (labeled C0121 in FIG. 16(e)). In general, a
conductor C_I_J_X_Y, couples embedded polarity region EPR_X_Y of a
pixel P(I, J) to switching element SE_X of pixel P(I, J-1), when J
is an odd number.
[0109] In pixels on even numbered rows, embedded polarity elements
of a first pixel are coupled to switching elements of the pixel
above the first pixel. For example, embedded polarity region
EPR_2_2 (labeled EPR22 in FIG. 16(e)) of pixel P(0, 0) is coupled
to switching element SE_2 of pixel P(0, 1) by conductor C_0_0_2_2
(labeled C0022 in FIG. 16(e)). Similarly, embedded polarity region
EPR_2_1 (labeled EPR21 in FIG. 16(e)) of pixel P(0, 0) is coupled
to switching element SE_2 of pixel P(0, 1) by conductor C_0_0_2_1
(labeled C0021 in FIG. 16(e)). In general, a conductor C_I_J_X_Y,
couples embedded polarity region EPR_X_Y of a pixel P(I, J) to
switching element SE_X of pixel P(I, J+1), when J is an even
number.
[0110] As explained above adjacent row of pixels have opposite
polarity in display 1630. Thus, providing polarity from switching
elements in pixels from adjacent rows to embedded polarity regions
as described above causes the polarity of the embedded polarity
regions to be different from the polarity of the color dot. This
differing polarity serves to enhance the fringe field in the color
dots and reduce the touch mura effect in display 1630.
[0111] FIG. 16(f) shows another embodiment of the present invention
in which the embedded polarity regions receive polarity from the
fringe field amplifying region. Specifically, FIG. 16(f) shows a
portion of a display 1640 using pixels P(0, 0), P(1, 0), P(0, 1),
and P(1, 1) of pixel design 1610 with a switching element row
inversion driving scheme. Display 1640 could have thousands of rows
with thousand of pixels on each row. The rows and columns would
continue from the portion shown in FIG. 16(f) in the manner shown
in FIG. 16(f). For clarity, the gate lines and source lines that
control the switching elements are omitted in FIG. 16(f).
Furthermore, to better illustrate each pixel, the area of each
pixel is shaded; this shading is only for illustrative purposes in
FIG. 16(f) and has no functional significance. Due to space
limitations color dots are labeled as CDXY as opposed to CD_X_Y and
embedded polarity regions are labeled as EPRXY as opposed to
EPR_X_Y.
[0112] Because display 1640 and display 1620 are very similar only
the differences are described in detail. For example, the pixels of
display 1640 are arranged in the same manner as the pixels of
display 1620. Furthermore, the polarity of the color dots,
switching elements and fringe field amplifying regions are the
same. Thus like in display 1620, a pixel P(x, y) in display 1640
also has a first dot polarity pattern when y is even and a second
dot polarity pattern when y is odd. The primary difference between
display 1620 and display 1640 is that the polarity for the embedded
polarized regions in display 1640 is provided from the fringe field
amplifying regions rather than from dedicated embedded polarity
switching elements which were used in display 1620.
[0113] Specifically, as illustrated in FIG. 16(f), in display 1640
each embedded polarity regions is coupled to the nearest fringe
fiend amplifying region. Specifically, an embedded polarity region
EPR_X_Y of a pixel P(I, J) is coupled to fringe field amplifying
region FFAR_X by a conductor C_I_J_X_Y (labeled with CIJXY in FIG.
16(f) due to space constraints), where I, J denotes the pixel (e.g.
pixel P(I, J), X is the color component, Y denotes the color dot
(e.g. color dot CD_X_Y (shortened in FIG. 16(f) as CDXY)) within
the pixel. For example, conductor C0112 couples embedded polarity
region EPR12 of pixel P(0, 1) to fringe field amplifying region
FFAR_1 (not specifically labeled FIG. 16(f)) of pixel P(0, 1). The
conductors for the embedded polarity regions are shown with dashed
lines to indicate that the conductors are in a different plane from
the color dots. Typically, the color dots and fringe field
amplifying regions are formed with ITO in a first plane and the
conductors are formed with a metal layer in a second plane. Thus, a
via (labeled V) is used to connect the fringe field amplifying
regions to the conductors. In FIG. 16(f) the fringe field
amplifying regions are coupled to a switching element of a
neighboring pixel as explained above with respect to FIG. 16(d).
However, in other embodiments of the present invention the fringe
field amplifying regions may receive polarity using other methods,
such as dedicated fringe field amplifying region switching
elements.
[0114] As explained above the fringe field amplifying regions have
an opposite polarity as compared to the color dots. Thus, providing
polarity from the fringe field amplifying regions to the embedded
polarity regions causes the polarity of the embedded polarity
regions to be different from the polarity of the color dot. This
differing polarity serves to enhance the fringe field in the color
dots and reduce the touch mura effect in display 1630.
[0115] Pixel design 1610 can be easily modified for use with
switching element point inversion driving schemes in accordance
with another embodiment of the present invention. FIG. 17(a)-17(b)
show different dot polarity pattern of a pixel design 1710 that is
a modified version of pixel design 1610 (FIGS. 16(a)-16(b)).
Specifically, in FIG. 17(a), pixel design 1710 has a positive dot
polarity pattern (and is thus labeled 1710+) and in FIG. 17(b),
pixel design 1710 has a negative dot polarity pattern (and is thus
labeled 1610-). Furthermore, the polarity of each polarized
component in the various pixel designs are indicated with "+" for
positive polarity or "-" for negative polarity.
[0116] Pixel design 1710 has three color components CC_1, CC_2 and
CC_3 (not labeled in FIGS. 17(a)-17(b)). Each of the three color
components includes two color dots. Pixel design 1710 also includes
a switching element for each color component (referenced as SE_1,
SE_2, and SE_3) and a fringe field amplifying region for each color
component (referenced as FFAR_1, FFAR_2, and FFAR_3). The layout of
the color dots, switching elements and fringe field amplifying
regions in pixel design 1710 are identical to the layout of pixel
design 1610. Thus, for brevity the description of the layout is not
repeated. Switching elements SE_1, SE_2, and SE_3 are coupled to
color components CC_1, CC_2, and CC_3, respectively, in the same
manner as described above with regards to pixel design 1610.
[0117] Just as in pixel design 1610, each color dot of pixel design
1710 includes an embedded polarity region which would minimize any
touch mura effects in the color dot. Because the placement of the
embedded polarity regions are the same in pixel design 1710 and
pixel design 1610, the description is not repeated. Generally, each
color dot has an embedded polarity region centered within the color
dot.
[0118] As explained above, the polarity of the embedded polarity
region differs from that of the color dot. Thus, the polarity of
the embedded polarity regions are controlled by a polarity source
different from switching element SE_1 controlling the color dot
containing the embedded polarity region. As described above, in
some embodiments of the present invention, a display includes
dedicated embedded-polarity-region switching elements to control
the polarity of the embedded polarity regions (See FIG. 16(d) for
one such embodiment). Other embodiments of the present invention,
may couple the embedded polarity regions to other elements of the
pixel that have a differing polarity (See, FIG. 16(f)).
[0119] The fringe field amplifying regions (FFAR_1, FFAR_2, and
FFAR_3) of pixel design 1710 are the same as in pixel design 1610.
Thus the detailed view provided in FIG. 16(c) and described above,
also applies to pixel design 1710. Furthermore, the placement of
the fringe field amplifying region in pixel design 1710 is the same
as in pixel design 1610 as described above.
[0120] The polarities of the color dots, fringe field amplifying
regions, and switching elements are shown using "+" and "-" signs.
Pixel design 1710 is designed for use in displays having switching
element point inversion driving schemes, but can also be used with
displays having switching element column inversion driving scheme.
Thus, in FIG. 17(a), which shows the positive dot polarity pattern
of pixel design 1710+, switching elements SE_1 and SE3, color dots
CD_1_1, CD_1_2, CD_3_1, and 3_2; and fringe field amplifying region
FFAR_2 have positive polarity. In contrast, switching element SE_2,
color dots CD_2_1 and CD_2_2; and fringe field amplifying regions
FFAR_1 and FFAR2 have negative polarity. As explained above,
Embedded polarity regions may have the same direction of polarity
(i.e. positive or negative) as the color dot but have a different
magnitude of polarity. Alternatively, embedded polarity regions may
have different polarity (i.e. "direction of polarity") than the
color dot (e.g. positive polarity for color dot polarity with
negative polarity for embedded polarity regions). In addition,
embedded polarity regions can have neutral polarity. In a
particular embodiment of the present invention, the embedded
polarity regions of pixel design 1710 have different polarity than
the color dots. Thus for this embodiment, embedded polarity regions
EPR_1_1, EPR_1_2, EPR_3_1, and EPR_3_2 would have negative polarity
in FIG. 17(a); while embedded polarity regions EPR_2_1 EPR_2_2
would have positive polarity.
[0121] The polarities of the color dots, fringe field amplifying
regions, and switching elements are shown using "+" and "-" signs.
Pixel design 1710 is designed for use in displays having switching
element point inversion driving schemes, but can also be used with
displays having switching element column inversion driving scheme.
Thus, in FIG. 17(a), which shows the positive dot polarity pattern
of pixel design 1710+, switching elements SE_1 and SE3, color dots
CD_1_1, CD_1_2, CD_3_1, and 3_2; and fringe field amplifying region
FFAR_2 have positive polarity. In contrast, switching element SE_2,
color dots CD_2_1 and CD_2_2; and fringe field amplifying regions
FFAR_1 and FFAR2 have negative polarity. As explained above,
embedded polarity regions may have the same direction of polarity
(i.e. positive or negative) as the color dot but have a different
magnitude of polarity. Alternatively, embedded polarity regions may
have different polarity (i.e. "direction of polarity") than the
color dot (e.g. positive polarity for color dot polarity with
negative polarity for embedded polarity regions). In addition,
embedded polarity regions can have neutral polarity. In a
particular embodiment of the present invention, the embedded
polarity regions of pixel design 1710 have different polarity than
the color dots. Thus for this embodiment, embedded polarity regions
EPR_1_1, EPR_1_2, EPR_3_1, and EPR_3_2 would have negative polarity
in FIG. 17(a); while embedded polarity regions EPR_2_1 EPR_2_2
would have positive polarity.
[0122] In FIG. 17(b), which shows the positive dot polarity pattern
of pixel design 1710+, switching elements SE_1 and SE3, color dots
CD_1_1, CD_1_2, CD_3_1, and 3_2; and fringe field amplifying region
FFAR_2 have negative polarity. In contrast, switching element SE_2,
color dots CD_2_1 and CD_2_2; and fringe field amplifying regions
FFAR_1 and FFAR2 have positive polarity. As explained above,
embedded polarity regions may have the same direction of polarity
(i.e. positive or negative) as the color dot but have a different
magnitude of polarity. Alternatively, embedded polarity regions may
have different polarity (i.e. "direction of polarity") than the
color dot (e.g. positive polarity for color dot polarity with
negative polarity for embedded polarity regions). In addition,
embedded polarity regions can have neutral polarity. In a
particular embodiment of the present invention, the embedded
polarity regions of pixel design 1710 have different polarity than
the color dots. Thus for this embodiment, embedded polarity regions
EPR_1_1, EPR_1_2, EPR_3_1, and EPR_3_2 would have positive polarity
in FIG. 17(b); while embedded polarity regions EPR_2_1 and EPR_2_2
would have negative polarity.
[0123] Unlike the switching elements if pixel design 1610, the
switching elements in pixel design 1710 have both positive and
negative polarity. Specifically, switching elements SE_1 and SE_3
have one polarity while switching element SE_2 has the other
polarity. Thus, the fringe field amplifying regions could be
polarized from the switching elements within pixel design 1710.
FIG. 17(c) described below shows a pixel design 1710-1, in
accordance with one embodiment of the present invention in which
the fringe field amplifying regions are polarized from within pixel
design 1710. In other embodiments, the fringe field amplifying
regions are driven by an external polarity source, i.e. a polarity
source from outside the specific pixel of pixel design 1710.
Various sources of opposite polarity can be used in accordance with
differing embodiments of the present invention. For example
specific fringe field amplifying region switching elements may be
used or switching elements of nearby pixels having the appropriate
dot polarity could also used to drive the fringe field amplifying
regions. In the embodiments of FIGS. 17(a)-17(b), switching
elements of nearby pixels having the appropriate dot polarity could
also used to drive the fringe field amplifying regions. Therefore,
pixel design 1710 includes conductor to facilitate coupling the
fringe field amplifying regions to switching elements in other
pixels. Specifically, a conductor 1712 of a current pixel would
couple the electrode of fringe field amplifying region FFAR_1 to
switching element SE_1 (see FIGS. 17(d) and 17(e)) of a pixel above
the current pixel. The connection to the switching element would be
via the electrodes of the color dots of the pixel above the current
pixel. Similarly, a conductor 1714 of a current pixel would couple
the electrode of fringe field amplifying region FFAR_2 to switching
element SE_2 (see FIGS. 17(d)) of a pixel above the current pixel.
The connection to the switching element would be via the electrodes
of the color dots of the pixel above the current pixel. A conductor
1716 of a current pixel would couple the electrode of fringe field
amplifying region FFAR_3 to switching element SE_3 (see FIGS. 17(d)
and 17(e)) of a pixel above the current pixel. The connection to
the switching element would be via the electrodes of the color dots
of the pixel above the current pixel. These connections are better
shown in FIGS. 17(d) and 17(e) which are described below.
[0124] FIG. 17(c) shows a pixel design 1710-1 which is a modified
version of pixel design 1710. Since the pixel designs are similar
only the differences are described. Specifically in pixel design
1710-1, conductors 1712, 1714, and 1716 are replaced with
conductors 1713, 1715, and 1717, respectively. Conductor 1713
couples fringe field amplifying region FFAR_1 to switching element
SE_2, which has negative polarity. Conductor 1715 couples fringe
field amplifying region FFAR_2 to switching element SE_3, which has
positive polarity. Conductor 1717 couples fringe field amplifying
region FFAR_3 to switching element SE_2, which has negative
polarity.
[0125] FIG. 17(d) shows a portion of display 1720 using pixels P(0,
0), P(1, 0), P(0, 1), and P(1, 1) of pixel design 1710 with a
switching element row inversion driving scheme. Display 1720 could
have thousands of rows with thousand of pixels on each row. The
rows and columns would continue from the portion shown in FIG.
17(d) in the manner shown in FIG. 17(d). For clarity, the gate
lines and source lines that control the switching elements are
omitted in FIG. 17(d). Furthermore, to better illustrate each
pixel, the area of each pixel is shaded; this shading is only for
illustrative purposes in FIG. 17(d) and has no functional
significance. Due to space limitations color dots are labeled as
CDXY as opposed to CD_X_Y and embedded polarity regions are labeled
as EPRXY as opposed to EPR_X_Y.
[0126] The pixels of display 1720 are arranged so that pixels in a
row alternate between the positive dot polarity pattern and the
negative dot polarity pattern. Furthermore, pixels in a column also
alternate between the positive dot polarity pattern and the
negative dot polarity pattern. Thus, pixels P(0, 0) and P(1, 1)
have the positive dot polarity pattern and pixels P(0, 1) and P(1,
0) have the negative dot polarity pattern. However, at the next
frame the pixels will switch dot polarity patterns. Thus in general
a pixel P(x, y) has a first dot polarity pattern when x+y is even
and a second dot polarity pattern when x+y is odd. Internal
conductors 1712, 1714, and 1716 in pixel design 1710, provide
polarity to the fringe field amplifying regions. Specifically,
fringe field amplifying regions of a first pixel receive voltage
polarity and voltage magnitude from a second pixel. Specifically,
the second pixel is the pixel above the first pixel. For example,
the electrodes of fringe field amplifying region FFAR_1 of pixel
P(0, 0) is coupled to switching elements SE_1 of pixel P(0, 1) via
the electrodes of color dots CD_1_2 of pixel P(0, 1). Similarly,
the electrodes of fringe field amplifying regions FFAR_2 and FFAR_3
of pixel P(0, 0) are coupled to switching elements SE_2, and SE_3
of pixel P(0, 1) via color dots CD_2_2, and CD_3_2 of pixel P(0,
1), respectively.
[0127] In display 1720, a first pixel is paired with a second
pixel, so that the embedded polarity regions of the first pixel is
coupled to the switching element of the second pixel and the
embedded polarity regions of the second pixel is coupled to the
switching elements of the first pixel. Specifically, pixels on even
numbered rows are paired with the pixel in the odd numbered row
above the even numbered row. Thus in FIG. 17(d), pixel P(0, 0) is
paired with Pixel P(0, 1) and pixel P(1, 0) is paired with pixel
P(1, 1). In general, a pixel P(X, Y) is paired with a pixel P(X,
Y+1) if Y is even. Conversely, a pixel P(x, Y) is paired with pixel
P(X, Y-1) if Y is odd.
[0128] As illustrated in FIG. 17(d), in display 1720 each embedded
polarity regions is coupled to a switching element of paired pixel
by a conductor C_I_J_X_Y (labeled with CIJXY in FIG. 17(d) due to
space constraints), where I, J denotes the pixel (e.g. pixel P(I,
J) containing the embedded polarity region, X is the color
component, and Y denotes the color dot (e.g. color dot CD_X_Y
(shortened in FIG. 17(d) as CDXY)) within the pixel. For example,
conductor C0112 couples embedded polarity region EPR12 of pixel
P(0, 1) to switching element SE_1 of pixel P(0, 0). The conductors
for the embedded polarity regions are shown with dashed lines to
indicate that the conductors are in a different plane from the
color dots. Typically, the color dots are formed with ITO in a
first plane and the conductors are formed with a metal layer in a
second plane.
[0129] As explained above in pixels on odd numbered rows, embedded
polarity elements of a first pixel are coupled to switching
elements of the pixel below the first pixel. For example, embedded
polarity region EPR_2_2 (labeled EPR22 in FIG. 17(d)) of pixel P(0,
1) is coupled to switching element SE_2 of pixel P(0, 0) by
conductor C_0_1_2_2 (labeled C0122 in FIG. 17(d)). Similarly,
embedded polarity region EPR_2_1 (labeled EPR21 in FIG. 17(d)) of
pixel P(0, 1) is coupled to switching element SE_2 of pixel P(0, 0)
by conductor C_0_1_2_1 (labeled C0121 in FIG. 17(d)). In general, a
conductor C_I_J_X_Y, couples embedded polarity region EPR_X_Y of a
pixel P(I, J) to switching element SE_X of pixel P(I, J-1), when J
is an odd number.
[0130] In pixels on even numbered rows, embedded polarity elements
of a first pixel are coupled to switching elements of the pixel
above the first pixel. For example, embedded polarity region
EPR_2_2 (labeled EPR22 in FIG. 17(d)) of pixel P(0, 0) is coupled
to switching element SE_2 of pixel P(0, 1) by conductor C_0_0_2_2
(labeled C0022 in FIG. 17(d)). Similarly, embedded polarity region
EPR_2_1 (labeled EPR21 in FIG. 17(d)) of pixel P(0, 0) is coupled
to switching element SE_2 of pixel P(0, 1) by conductor C_0_0_2_1
(labeled C0021 in FIG. 17(d)). In general, a conductor C_I_J_X_Y,
couples embedded polarity region EPR_X_Y of a pixel P(I, J) to
switching element SE_X of pixel P(I, J+1), when J is an even
number.
[0131] As explained above adjacent row of pixels have opposite
polarity in display 1720. Thus, providing polarity from switching
elements in pixels from adjacent rows to embedded polarity regions
as described above causes the polarity of the embedded polarity
regions to be different from the polarity of the color dot. This
differing polarity serves to enhance the fringe field in the color
dots and reduce the touch mura effect in display 1720.
[0132] As explained above adjacent row of pixels have opposite
polarity in display 1720. Thus, providing polarity from switching
elements in pixels from adjacent rows to embedded polarity regions
as described above causes the polarity of the embedded polarity
regions to be different from the polarity of the color dot. This
differing polarity serves to enhance the fringe field in the color
dots and reduce the touch mura effect in display 1720.
[0133] FIG. 17(e) shows another embodiment of the present invention
in which the embedded polarity regions receive polarity from the
fringe field amplifying region. Specifically, FIG. 17(e) shows a
portion of a display 1730 using pixels P(0, 0), P(1, 0), P(0, 1),
and P(1, 1) of pixel design 1710 with a switching element point
inversion driving scheme. Display 1730 could have thousands of rows
with thousand of pixels on each row. The rows and columns would
continue from the portion shown in FIG. 17(e) in the manner shown
in FIG. 17(e). For clarity, the gate lines and source lines that
control the switching elements are omitted in FIG. 17(e).
Furthermore, to better illustrate each pixel, the area of each
pixel is shaded; this shading is only for illustrative purposes in
FIG. 17(e) and has no functional significance. Due to space
limitations color dots are labeled as CDXY as opposed to CD_X_Y and
embedded polarity regions are labeled as EPRXY as opposed to
EPR_X_Y.
[0134] Because display 1730 and display 1720 are very similar only
the differences are described in detail. For example, the pixels of
display 1730 are arranged in the same manner as the pixels of
display 1720. Furthermore, the polarity of the color dots,
switching elements and fringe field amplifying regions are the
same. Thus like in display 1720, a pixel P(x, y) in display 1730
also has a first dot polarity pattern when x+y is even and a second
dot polarity pattern when x+y is odd. The primary difference
between display 1720 and display 1730 is that the embedded
polarized regions in display 1730 is coupled to the fringe field
amplifying regions to receive polarity.
[0135] Specifically, as illustrated in FIG. 17(e), in display 1730
each embedded polarity regions is coupled to the nearest fringe
fiend amplifying region. Specifically, an embedded polarity region
EPR_X_Y of a pixel P(I, J) is coupled to fringe field amplifying
region FFAR_X by a conductor C_I_J_X_Y (labeled with CIJXY in FIG.
17(e) due to space constraints), where I, J denotes the pixel (e.g.
pixel P(I, J), X is the color component, Y denotes the color dot
(e.g. color dot CD_X_Y (shortened in FIG. 17(e) as CDXY)) within
the pixel. For example, conductor C0112 couples embedded polarity
region EPR12 of pixel P(0, 1) to fringe field amplifying region
FFAR_1 (not specifically labeled FIG. 17(e)) of pixel P(0, 1). The
conductors for the embedded polarity regions are shown with dashed
lines to indicate that the conductors are in a different plane from
the color dots. Typically, the color dots and fringe field
amplifying regions are formed with ITO in a first plane and the
conductors are formed with a metal layer in a second plane. Thus, a
via (labeled V) is used to connect the fringe field amplifying
regions to the conductors. In FIG. 17(e) the fringe field
amplifying regions are coupled to a switching element of a
neighboring pixel as explained above with respect to FIG. 17(d).
However, in other embodiments of the present invention the fringe
field amplifying regions may receive polarity using other methods,
such as dedicated fringe field amplifying region switching
elements.
[0136] As explained above the fringe field amplifying regions have
an opposite polarity as compared to the color dots. Thus, providing
polarity from the fringe field amplifying regions to the embedded
polarity regions causes the polarity of the embedded polarity
regions to be different from the polarity of the color dot. This
differing polarity serves to enhance the fringe field in the color
dots and reduce the touch mura effect in display 1720.
[0137] In the various embodiments of the present invention, novel
structures and methods have been described for creating a
multi-domain vertical alignment liquid crystal display without the
use of physical features on the substrate. The various embodiments
of the structures and methods of this invention that are described
above are illustrative only of the principles of this invention and
are not intended to limit the scope of the invention to the
particular embodiment described. For example, in view of this
disclosure those skilled in the art can define other pixel
definitions, embedded polarity regions, field reduction layers,
insulating layers, conducting layers, voids, dot polarity patterns,
pixel designs, color components, polarity extension regions,
polarities, fringe fields, electrodes, substrates, films, and so
forth, and use these alternative features to create a method or
system according to the principles of this invention. Thus, the
invention is limited only by the following claims.
* * * * *