U.S. patent application number 14/695213 was filed with the patent office on 2015-08-13 for display panel and method for manufacturing the same.
The applicant listed for this patent is Samsung Display Co., Ltd.. Invention is credited to Gak-Seok LEE, Taek-Joon LEE, Keun-Chan OH.
Application Number | 20150227005 14/695213 |
Document ID | / |
Family ID | 50187131 |
Filed Date | 2015-08-13 |
United States Patent
Application |
20150227005 |
Kind Code |
A1 |
LEE; Gak-Seok ; et
al. |
August 13, 2015 |
DISPLAY PANEL AND METHOD FOR MANUFACTURING THE SAME
Abstract
A display panel includes a first substrate including a common
electrode, a second substrate including a first solid pixel
electrode and a second solid pixel electrode, and a liquid crystal
layer including liquid crystal between the first substrate and the
second substrate. The second solid pixel electrode is spaced apart
from the first solid pixel electrode, and surrounds the first solid
pixel electrode.
Inventors: |
LEE; Gak-Seok; (Cheonan-si,
KR) ; OH; Keun-Chan; (Cheonan-si, KR) ; LEE;
Taek-Joon; (Hwaseong-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Display Co., Ltd. |
Yongin-City |
|
KR |
|
|
Family ID: |
50187131 |
Appl. No.: |
14/695213 |
Filed: |
April 24, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13748699 |
Jan 24, 2013 |
9069217 |
|
|
14695213 |
|
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|
Current U.S.
Class: |
349/33 ;
349/139 |
Current CPC
Class: |
G02F 2001/134345
20130101; G02F 1/1333 20130101; G02F 1/134309 20130101; G02F
2001/133757 20130101; G02F 1/133753 20130101; G02F 1/13439
20130101 |
International
Class: |
G02F 1/1337 20060101
G02F001/1337; G02F 1/1343 20060101 G02F001/1343 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2012 |
KR |
10-2012-0098271 |
Claims
1. A display panel comprising: a unit pixel in which a plurality of
domains are arranged with respect to a center of the unit pixel,
the unit pixel comprising: a first substrate comprising a common
electrode disposed in each domain of the unit pixel; a second
substrate comprising: a first solid pixel electrode, a portion of
which is disposed in each domain of the unit pixel; and a second
solid pixel electrode spaced apart from and surrounding the first
solid pixel electrode within the unit pixel, a portion of which is
disposed in each domain of the unit pixel, and a liquid crystal
layer comprising liquid crystal molecules disposed between the
first substrate and the second substrate, the liquid crystal
molecules defining the plurality of domains of the unit pixel.
2. The display panel of claim 1, wherein within each domain among
the plurality of domains defined by the liquid crystal molecules,
each of the liquid crystal molecules disposed within the domain is
oriented in a direction toward the center of the unit pixel, and
within a same domain, arrangements of the liquid crystal molecules
oriented in the direction toward the center of the unit pixel are
different from each other.
3. The display panel of claim 2, wherein within the same domain,
pre-tilts of first liquid crystal molecules disposed between the
common electrode and the first solid pixel electrode are different
from pre-tilts of second liquid crystal molecules disposed between
the common electrode and the second solid pixel electrode.
4. The display panel of claim 3, wherein the pre-tilts of the first
liquid crystal molecules are provided by applying a common voltage
to the common electrode and by applying a first voltage to the
first solid pixel electrode.
5. The display panel of claim 4, wherein the pre-tilts of the
second liquid crystal molecules are provided by applying the common
voltage to the common electrode and by applying a second voltage to
the second solid pixel electrode, wherein the second voltage is
lower than the first voltage.
6. The display panel of claim 3, wherein the pre-tilts of the
second liquid crystal molecules are provided after the pre-tilts of
the first liquid crystal molecules are provided.
7. The display panel of claim 1, wherein the first solid pixel
electrode comprises a substantially rhombus-shape body portion.
8. The display panel of claim 7, wherein the first solid pixel
electrode further comprises a plurality of extension portions
respectively extending from an apex of the rhombus-shaped body
portion.
9. The display panel of claim 8, wherein liquid crystal molecules
disposed in interfaces of the domains are controlled by the
extension portions.
10. The display panel of claim 1, wherein the first solid pixel
electrode comprises a central controlling portion at a center of
the first solid pixel electrode.
11. The display panel of claim 10, wherein liquid crystal molecules
disposed at the center of the unit pixel are controlled by the
central controlling portion.
12. The display panel of claim 1, wherein the second solid pixel
electrode comprises a peripheral controlling portion extending
along an outer edge of the second solid pixel electrode.
13. The display panel of claim 12, wherein liquid crystal molecules
disposed adjacent to edges of the second solid pixel electrode are
controlled by the peripheral controlling portion.
Description
[0001] This application is a continuation application of U.S.
patent application Ser. No. 13/748,699 filed on Jan. 24, 2013,
which claims priority to Korean Patent Application No.
10-2012-0098271, filed on Sep. 5, 2012, and all the benefits
accruing therefrom under 35 U.S.C. .sctn.119, the contents of which
are incorporated by reference herein in their entireties.
BACKGROUND
[0002] 1. Field
[0003] Exemplary embodiments of the invention relate to a display
panel and a method of manufacturing the display panel.
[0004] More particularly, one or more exemplary embodiment of the
invention relates to a display panel capable of improving a display
quality, and a method of manufacturing the display panel
[0005] 2. Description of the Related Art
[0006] A liquid crystal display apparatus changes an arrangement of
liquid crystal using an electric field. Accordingly, transmittance
of the liquid crystal is controlled to display an image. Thus, the
liquid crystal display apparatus controls the electric field to
display the image.
[0007] A common electrode and a pixel electrode of the liquid
crystal display apparatus form the electric field. For example, a
liquid crystal layer including the liquid crystal is disposed
between the common electrode and the pixel electrode. Specific
voltages are applied to the common electrode and the pixel
electrode to form the electric field, so that the electric field
changes the arrangement of the liquid crystal.
[0008] A liquid crystal display apparatus has been developed to
include a pixel electrode having a slit pattern. The pixel
electrode having the slit pattern is substantially the same as a
plurality of electrodes each having a narrow width and spaced apart
from an adjacent electrode by a specific gap. The gap between
adjacent electrodes may influence formation of the electric
field.
[0009] During a manufacturing process, a non-uniform gap between
the adjacent electrodes may be formed, so that a non-uniform
electric field may be undesirably formed with the common electrode.
Accordingly, the image displayed on a liquid crystal display
apparatus having the non-uniform electric field may undesirably
include a non-uniform brightness, such as due to bright spots, and
a decrease in display quality. Therefore, there remains a need for
an improved display apparatus having a uniform electric field even
if a process error occurs in manufacturing the electrodes of the
display apparatus.
SUMMARY
[0010] One or more exemplary embodiment of the invention provides a
display panel unaffected by an error of a pixel gap, and a method
of manufacturing the display panel.
[0011] According to an exemplary embodiment of the invention, a
display panel includes a first substrate including a common
electrode, a second substrate including a first solid pixel
electrode and a second solid pixel electrode, and a liquid crystal
layer disposed between the first substrate and the second
substrate. The second solid pixel electrode is spaced apart from
the first solid pixel electrode, and surrounds the first solid
pixel electrode.
[0012] In an exemplary embodiment, the first solid pixel electrode
may include a substantially rhombus-shaped body portion.
[0013] In an exemplary embodiment, the first solid pixel electrode
may be symmetric with respect to a center of the first solid pixel
electrode.
[0014] In an exemplary embodiment, the first solid pixel electrode
may further include a plurality of extension portions respectively
extending from an apex of the rhombus-shaped body portion.
[0015] In an exemplary embodiment, the extension portions may be
symmetric with respect to a center of the first solid pixel
electrode.
[0016] In an exemplary embodiment, the first solid pixel electrode
may include four extension portions.
[0017] In an exemplary embodiment, the first solid pixel electrode
may further include a central controlling portion disposed at a
center of the first solid pixel electrode.
[0018] In an exemplary embodiment, the central controlling portion
may be an opening defined in the first solid pixel electrode, at
the center of the first solid pixel electrode.
[0019] In an exemplary embodiment, the second solid pixel electrode
may include a peripheral controlling portion which extends along an
edge of the second solid pixel electrode.
[0020] In an exemplary embodiment, the peripheral controlling
portion may be an opening defined in the second solid pixel
electrode and extended along the edge of the second solid pixel
electrode.
[0021] In an exemplary embodiment, the first solid pixel electrode
and the second solid pixel electrode may be in a same layer of the
display panel.
[0022] In an exemplary embodiment, a pre-tilt of the liquid crystal
on the first solid pixel electrode and a pre-tilt of the liquid
crystal on the second solid pixel electrode may be different from
each other.
[0023] According to an exemplary embodiment of the invention, a
method of manufacturing a display panel includes providing a common
electrode on a first substrate, providing a unit pixel including a
first solid pixel electrode and a second solid pixel electrode on a
second substrate, providing a liquid crystal layer including liquid
crystal between the first substrate and the second substrate, and
providing a pre-tilt of the liquid crystal. The second solid pixel
electrode is spaced apart from the first solid pixel electrode, and
surrounds the first solid pixel electrode.
[0024] In an exemplary embodiment, the pre-tilt of the liquid
crystal on the first solid pixel electrode and the pre-tilt of the
liquid crystal on the second solid pixel electrode may be different
from each other.
[0025] In an exemplary embodiment, the providing a pre-tilt of the
liquid crystal may include providing a first pre-tilt of the liquid
crystal which is disposed on the first solid pixel electrode, and
providing a second pre-tilt of the liquid crystal which is disposed
on the second solid pixel electrode.
[0026] In an exemplary embodiment, the providing a second pre-tilt
may be after the providing a first pre-tilt.
[0027] In an exemplary embodiment, the providing a first pre-tilt
and the providing a second pre-tilt may include a
photoreaction.
[0028] In an exemplary embodiment, the providing forming a first
pre-tilt may include applying a first voltage to the first solid
pixel electrode.
[0029] In an exemplary embodiment, the providing a second pre-tilt
may include applying a second voltage to the second solid pixel
electrode, and the second voltage may be lower than the first
voltage.
[0030] In an exemplary embodiment, the first solid pixel electrode
may include a substantially rhombus-shaped body portion.
[0031] In an exemplary embodiment, the first solid pixel electrode
may further include a plurality of extension portions respectively
extending from an apex of the rhombus-shaped body portion.
[0032] In an exemplary embodiment, the first solid pixel electrode
may further include a central controlling portion disposed at a
center of the first solid pixel electrode. The central controlling
portion may be an opening defined in the first solid pixel
electrode.
[0033] In an exemplary embodiment, the second solid pixel electrode
may further include a peripheral controlling portion which extends
along an edge of the second solid pixel electrode. The peripheral
controlling portion may be an opening defined in the second solid
pixel electrode.
[0034] According to one or more exemplary embodiment of the
invention, liquid crystal is arranged by an electric field between
a common electrode and a first solid pixel electrode, an electric
field between the common electrode and a second solid pixel
electrode, and an electric field between the first solid pixel
electrode and the second solid pixel electrode. Thus, although an
error in a pixel gap between the first solid pixel electrode and
the second solid pixel electrode may occur, a transmittance of the
liquid crystal may not be influenced by the error. Therefore, a
display quality of a display panel according to one or more
exemplary embodiment of the invention may be improved in comparison
with a conventional display panel having a slit structure pixel
electrode.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The above and other features of the invention will become
more apparent by describing in detail exemplary embodiments thereof
with reference to the accompanying drawings, in which:
[0036] FIG. 1 is a perspective view illustrating an exemplary
embodiment of a display panel according to the invention;
[0037] FIG. 2 is a perspective view illustrating an exemplary
embodiment of a unit pixel of a display panel according to the
invention;
[0038] FIG. 3 is a cross-sectional view taken along line I-I' of
FIG. 2;
[0039] FIG. 4 is a plan view illustrating the unit pixel of FIG.
2;
[0040] FIG. 5 is a plan view illustrating an arrangement of liquid
crystal with respect to the unit pixel of FIG. 2;
[0041] FIG. 6 is a plan view illustrating another exemplary
embodiment of a unit pixel of a display panel according to the
invention;
[0042] FIG. 7 is a plan view illustrating an arrangement of liquid
crystal with respect to the unit pixel of FIG. 6;
[0043] FIGS. 8A to 8C are plan views illustrating still other
exemplary embodiments of a unit pixel of a display panel according
to the invention;
[0044] FIGS. 9A and 9B are circuit diagrams illustrating yet
another exemplary embodiment of a unit pixel according to the
invention;
[0045] FIGS. 10A and 10B are cross-sectional views illustrating an
exemplary embodiment of forming liquid crystal having a pre-tilt
according to the invention;
[0046] FIG. 11 is a graph illustrating a transmittance in percent
(%) of a display panel in accordance with an applied voltage in
volts (V), of an exemplary embodiment of a display panel according
to the invention;
[0047] FIGS. 12A to 12E are photographs illustrating the
transmittance of a unit pixel represented in FIG. 11; and
[0048] FIGS. 13A and 13B are graphs illustrating a transmittance
difference in arbitrary units (a.u.) in accordance with an applied
voltage in volts (V), with respect to a gap between solid pixel
electrodes.
DETAILED DESCRIPTION
[0049] It will be understood that when an element or layer is
referred to as being "on" or "coupled to" another element or layer,
the element or layer can be directly on or connected to another
element or layer or intervening elements or layers. In contrast,
when an element is referred to as being "directly on" or "directly
connected to" another element or layer, there are no intervening
elements or layers present. As used herein, connected may refer to
elements being physically and/or electrically connected to each
other. Like numbers refer to like elements throughout. As used
herein, the term "and/or" includes any and all combinations of one
or more of the associated listed items.
[0050] It will be understood that, although the terms first,
second, third, etc., may be used herein to describe various
elements, components, regions, layers and/or sections, these
elements, components, regions, layers and/or sections should not be
limited by these terms. These terms are only used to distinguish
one element, component, region, layer or section from another
region, layer or section. Thus, a first element, component, region,
layer or section discussed below could be termed a second element,
component, region, layer or section without departing from the
teachings of the invention.
[0051] Spatially relative terms, such as ""below," "lower,"
"above," "upper" and the like, may be used herein for ease of
description to describe the relationship of one element or feature
to another element(s) or feature(s) as illustrated in the figures.
It will be understood that the spatially relative terms are
intended to encompass different orientations of the device in use
or operation, in addition to the orientation depicted in the
figures. For example, if the device in the figures is turned over,
elements described as "below" relative to other elements or
features would then be oriented "above" relative to the other
elements or features. Thus, the exemplary term "below" can
encompass both an orientation of above and below. The device may be
otherwise oriented (rotated 90 degrees or at other orientations)
and the spatially relative descriptors used herein interpreted
accordingly.
[0052] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a," "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises," "comprising," "includes" and/or
"including," when used in this specification, specify the presence
of stated features, integers, operations, elements, and/or
components, but do not preclude the presence or addition of one or
more other features, integers, steps, operations, elements,
components, and/or groups thereof.
[0053] Embodiments of the invention are described herein with
reference to cross-section illustrations that are schematic
illustrations of idealized embodiments (and intermediate
structures) of the invention. As such, variations from the shapes
of the illustrations as a result, for example, of manufacturing
techniques and/or tolerances, are to be expected. Thus, embodiments
of the invention should not be construed as limited to the
particular shapes of regions illustrated herein but are to include
deviations in shapes that result, for example, from
manufacturing.
[0054] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0055] All methods described herein can be performed in a suitable
order unless otherwise indicated herein or otherwise clearly
contradicted by context. The use of any and all examples, or
exemplary language (e.g., "such as"), is intended merely to better
illustrate the invention and does not pose a limitation on the
scope of the invention unless otherwise claimed. No language in the
specification should be construed as indicating any non-claimed
element as essential to the practice of the invention as used
herein.
[0056] Hereinafter, the invention will be explained in detail with
reference to the accompanying drawings.
[0057] FIG. 1 is a perspective view illustrating an exemplary
embodiment of a display panel according to the invention. FIG. 2 is
a perspective view illustrating an exemplary embodiment of a unit
pixel according to the invention.
[0058] Referring to FIG. 1, the display panel includes a first
substrate 300, a second substrate 100 and a liquid crystal layer
200 disposed between the first substrate 300 and a second substrate
100. The first substrate 300 may include a common electrode (not
shown). The second substrate 100 may include a pixel electrode (not
shown). An electric field between the common electrode and the
pixel electrode may control a transmittance of liquid crystal of
the liquid crystal layer 200. The second substrate 100 includes one
or more unit pixels. The one or more unit pixels are on a display
area of the second substrate 100. With a plurality of unit pixels,
each unit pixel displays a portion of an image, so that the display
panel may display the image.
[0059] Referring to FIG. 2, the unit pixel of the display includes
the first substrate 300, the second substrate 100 and the liquid
crystal layer 200. The first substrate 300 includes a first base
substrate 350, and a common electrode 310 disposed on the first
base substrate 350. The second substrate 100 includes a second base
substrate 150, a first solid pixel electrode 111 on the second
substrate 100 and a second solid pixel electrode 113 on the second
substrate 100.
[0060] The first solid pixel electrode 111 and the second solid
pixel electrode 113 are board-shaped or plate-shaped, and do not
include an opening, such as in a slit shape, defined therein. The
second solid pixel electrode 113 is spaced apart from the first
solid pixel electrode 111. In a plan view, the second solid pixel
electrode 113 surrounds the first solid pixel electrode 111, such
as completely surrounding and enclosing the first solid pixel
electrode 111. The first solid pixel electrode 111 is disposed on a
central portion of the unit pixel. The second solid pixel electrode
113 is disposed on a peripheral area of the unit pixel. The first
and/or second solid pixel electrode 111 and 113 may be a
continuous, single, unitary, indivisible member, but is not limited
thereto or thereby.
[0061] FIG. 3 is a cross-sectional view taken along line I-I' of
FIG. 2.
[0062] Referring to FIG. 3, the electric field respectively formed
by the common electrode 310, in cooperation with the first solid
pixel electrode 111 and the second solid pixel electrode 113,
controls an arrangement of liquid crystal molecules 210 in a liquid
crystal layer. Generally, an electric field is formed by one common
electrode and one pixel electrode to control the liquid crystal
molecules. However, in the illustrated exemplary embodiment, an
electric field is formed by the one common electrode 310 and the
first solid pixel electrode 111, and an electric field is also
formed by the same one common electrode 310 and the second solid
pixel electrode 113.
[0063] When the electric field is formed between the common
electrode 310 and the first solid pixel electrode 111, the liquid
crystal molecules are arranged toward a central portion of the unit
pixel. When the electric field is formed between the common
electrode 310 and the second solid pixel electrode 113, the liquid
crystal molecules between the common electrode 310 and the second
solid pixel electrode 113 are also arranged toward the central
portion of the unit pixel due to the electric field formed between
the common electrode 310 and the first solid pixel electrode 111.
Thus, all liquid crystal molecules 210 in the unit pixel are
arranged toward the central portion of the unit pixel.
[0064] FIG. 4 is a plan view illustrating the unit pixel of FIG.
2.
[0065] Referring to FIG. 4, a pixel electrode 110 of a unit pixel
includes the first solid pixel electrode 111, and the second solid
pixel electrode 113. The first solid pixel electrode 111 and the
second solid pixel electrode 113 are board-shaped or plate-shaped,
and do not include an opening or a slit defined therein. The first
solid pixel electrode 111 and the second solid pixel electrode 113
are spaced apart each other by a pixel gap 112. The pixel gap 112
may define a distance d between the spaced apart first and second
solid pixel electrodes 111 and 113. The distance d may be taken
perpendicular to a longitudinal axis of a respective portion of the
pixel gap 112, and may be otherwise referred to as a width of the
pixel gap 112.
[0066] The first solid pixel electrode 111 is in a central portion
of the pixel electrode 110. The second solid pixel electrode 113 is
in a peripheral area of the pixel electrode 110. The second solid
pixel electrode 113 surrounds the first solid pixel electrode 111.
The first solid pixel electrode 111 may be rhombus-shaped, but is
not limited thereto or thereby. The first solid pixel electrode 111
may be square-shaped in a unit pixel, but is not limited thereto or
thereby. When the first solid pixel electrode 111 is
rhombus-shaped, each apex of the first solid pixel electrode 111
respectively faces a center of a side of a tetragonal-shaped pixel
electrode 110. Where the unit pixel as including the pixel
electrode 110 is considered tetragonal-shaped, each of the apexes
of the rhombus-shaped first solid pixel electrode 111 respectively
faces a center of a side of the tetragonal-shaped unit pixel. Thus,
the first solid pixel electrode 111 is symmetric with respect to a
center of the pixel electrode 110 and/or a center of the unit
pixel.
[0067] FIG. 5 is a plan view illustrating an arrangement of liquid
crystal with respect to the unit pixel of FIG. 2
[0068] Referring to FIG. 5, in a display panel including the unit
pixel of FIG. 2, arrangement of liquid crystal in the unit pixel
includes four domains 200a, 200b, 200c and 200d. The arrangement of
liquid crystal in each of the four domains 200a, 200b, 200c and
200d is directed toward a center of the unit pixel as indicated by
the arrows. Arrangement of liquid crystal or arrangement of liquid
crystal molecules may be interchangeably used herein.
[0069] In general, liquid crystal molecules are arranged toward the
center of the unit pixel. In each of the domains 200a, 200b, 200c
and 200d, arrangements of the liquid crystal molecules are
different from each other. Thus, the domains 200a, 200b, 200c and
200d have arrangements of liquid crystal molecules different from
each other. Each of the domains 200a, 200b, 200c and 200d has an
arrangement of liquid crystal molecules different from that of
other domains, so that a viewing angle of the display panel may be
improved. In addition, the arrangements of liquid crystal molecules
different from each other may be formed by only two electrodes,
that is, the first solid pixel electrode and the second solid pixel
electrode, in cooperation with the common electrode 310.
[0070] Referring to FIG. 5 again, liquid crystal LO disposed
adjacent to an edge of the second solid pixel electrode 113, such
as adjacent to the outer edge, is influenced by the electric field
formed at the edge of the second solid pixel electrode 113. Liquid
crystal LI disposed in an interface of the domains is influenced by
the electric field formed between the first and second solid pixel
electrodes 111 and 113. Thus, an arrangement of liquid crystal
molecules (for example LO and LI) in a same domain (for example
200a) may be non-uniform and different from each other.
[0071] Especially, liquid crystal LC in a central portion of a unit
pixel may be tilted to a specific direction, instead of being
toward a center of the unit pixel, due to a distortion of the
electric field. This may decrease uniformity of an arrangement of
liquid crystal molecules in each domain 200a, 200b, 200c and
200d.
[0072] FIG. 6 is a plan view illustrating another exemplary
embodiment of a unit pixel of a display panel according to the
invention.
[0073] Referring to FIG. 6, a pixel electrode 110 of a display
panel includes a first solid pixel electrode 121 and a second solid
pixel electrode 123. The first solid pixel electrode 121 and the
second solid pixel electrode 123 are spaced apart from each other
by a pixel gap 112. The pixel gap 112 may define a distance d'
between the spaced apart first and second solid pixel electrodes
121 and 123. The distance d' may be taken perpendicular to a
longitudinal axis of a respective portion of the pixel gap 112, and
may be otherwise referred to as a width of the pixel gap 112. The
first solid pixel electrode 121 is disposed in a central area of
the pixel electrode 110. The second solid pixel electrode 123 is
disposed in a peripheral area of the pixel electrode 110.
[0074] The first solid pixel electrode 121 includes a body portion
1211, an extension portion 1212 and a central controlling portion
1213. The body portion 1211 is rhombus-shaped in the plan view.
[0075] The extension portion 1212 extends from each apex of the
rhombus-shaped body portion 1211. The extension portion 1212 is
extended from the body portion 1211 along a boundary of a domain of
the unit pixel. The extension portion 1212 may be symmetric with
reference to a center of the first solid pixel electrode 121. The
extension portion 1212 may be extended from each of four apexes of
the rhombus-shaped body portion 1211, so that four extension
portions 1212 of the first solid pixel electrode 121 may be in the
unit pixel. The pixel gap 112 may correspond to the profile of the
first solid pixel electrode 121 and be parallel to edges
thereof.
[0076] The central controlling portion 1213 is at the center of the
body portion 1211. The central controlling portion 1213 may reduce
or effectively prevent unwanted liquid crystal arrangement in the
central portion of the first solid pixel electrode 121. The central
controlling portion 1213 may be an opening defined in the body
portion 1211, at center of the body portion 1211. The opening may
be circular-shaped, quadrangular-shaped, etc. in the plan view, but
is not limited thereto or thereby. When the central controlling
portion 1213 is an opening, the electric field corresponding to the
central controlling portion 1213 is canceled or negated, so that
liquid crystal corresponding to the central controlling portion
1213 may not lean or tilt to a specific direction. Thus, unwanted
liquid crystal arrangement in the central portion of the unit pixel
may be reduced or effectively prevented.
[0077] In addition, the second solid pixel electrode 123 includes a
body portion 1231 and a peripheral controlling portion 1232. The
body portion 1231 surrounds the first solid pixel electrode 121,
and is spaced apart from the first solid pixel electrode 121 by the
pixel gap 112. The body portion 1231 may be plate-shaped, such as
tetragonal-shaped.
[0078] The peripheral controlling portion 1232 may be extended
along an edge of the unit pixel, such as an outer edge thereof. The
peripheral controlling portion 1232 may be extended along an edge
of the second solid pixel electrode 123, and spaced apart from an
outer edge of the second solid pixel electrode 123 by a specific
distance. The peripheral controlling portion 1232 may be an opening
defined in the body portion 1231 and extend along the outer edge of
the second solid pixel electrode 123. When the peripheral
controlling portion 1232 is the opening, the electric field formed
at the outer edge of the unit pixel may be canceled or negated by
the electric field formed at the peripheral controlling portion
1232, because a direction of the electric field formed at the
peripheral controlling portion 1232 is opposite to a direction of
the electric flied formed at the edge of the unit pixel. Thus,
liquid crystal molecules may be directed toward the central portion
of the unit pixel.
[0079] FIG. 7 is a plan view illustrating an arrangement of liquid
crystal with respect to the unit pixel of FIG. 6.
[0080] Referring to FIG. 7, an arrangement of liquid crystal is
uniform in each domain 200a, 200b, 200c and 200d. In contrast to
the exemplary embodiment of FIG. 5, arrangement of liquid crystal
in each domain 200a, 200b, 200c and 200d according to the exemplary
embodiment in FIG. 7 is regular and uniform.
[0081] Liquid crystal LI' disposed in an interface of the domains
is controlled by the extension portion 1212 of the first solid
pixel electrode 121. Thus, liquid crystal molecules of the liquid
crystal LI' may be arranged in a same direction as that of other
liquid crystal molecules in a same domain.
[0082] Liquid crystal LO' disposed adjacent to an edge of the
second solid pixel electrode 123 is controlled by the peripheral
controlling portion 1232, so that the liquid crystal LO' may not be
influenced by the electric field formed at the edge of the unit
pixel. Thus, liquid crystal molecules of the liquid crystal LO' may
be arranged in a same direction as that of other liquid crystal
molecules in a same domain.
[0083] Liquid crystal LC' disposed at the central portion of the
unit pixel is controlled by the central controlling portion 1213.
Thus, liquid crystal molecules of the liquid crystal LC' disposed
at the central portion of the unit pixel may not lean or tilt to a
specific direction.
[0084] Thus, arrangement of liquid crystal in each domain 200a,
200b, 200c and 200d may be regular and uniform.
[0085] FIGS. 8A to 8C are plan views illustrating still other
exemplary embodiments of a unit pixel of a display panel according
to the invention.
[0086] Although the above-described exemplary embodiments of a unit
pixel are square-shaped, alternatively, the unit pixel may have
various shapes. Many modifications of the unit pixel having a first
solid pixel electrode and a second pixel electrode may be
possible.
[0087] Referring to FIG. 8A, the pixel electrode 130 has a
longitudinal axis which extends from top to bottom and is overall
rectangular-shaped. The pixel electrode 130 includes a first solid
pixel electrode 131 and a second solid pixel electrode 133, similar
to the exemplary embodiment of FIG. 6. The first solid pixel
electrode 131 includes a body portion 1311, an extension portion
1312 and a central controlling portion 1313. The second solid pixel
electrode 133 includes a body portion 1331 and a peripheral
controlling portion 1332. A function of the pixel electrode 130 may
be same as that of the pixel electrode 110 in FIG. 6.
[0088] Referring to FIG. 8B, a collective pixel electrode 140 may
include a plurality of pixel electrodes, such as a first pixel
electrode 140a and a second pixel electrode 140b. The first and
second pixel electrodes 140a and 140b may form a unit pixel
electrode 140. Each of the pixel electrodes 140a and 140b of the
pixel electrode 140 is substantially same as the pixel electrode
110 of FIG. 6, except that the first pixel electrode 140a is
square-shaped, and the second pixel electrode 140b is
rectangular-shaped. The first and second pixel electrodes 140a and
140b may be arranged adjacent to each other along a longitudinal
axis of a unit pixel, but are not limited thereto or thereby.
[0089] Referring to FIG. 8C, a collective pixel electrode 145
includes a plurality of pixel electrodes, such as a first pixel
electrode 145a, a second pixel electrode 145b and a third pixel
electrode 145c. Each of the first to third pixel electrodes 145a,
145b and 145c is square-shaped. The first to third pixel electrodes
145a, 145b and 145c form a unit pixel electrode 145. Functions of
the each of the first to third pixel electrodes 145a, 145b and 145c
in FIG. 8C may be same as that of pixel electrode 110 of FIG.
6.
[0090] FIGS. 9A and 9B are circuit diagram illustrating yet another
exemplary embodiment of a unit pixel according to the
invention.
[0091] Two voltages may be applied to the first solid pixel
electrode and the second solid pixel electrode, respectively. To
drive the pixel electrode including the first solid pixel electrode
and the second solid pixel electrode, one gate line and one data
line for one pixel ("1G1D") or one gate line and two data lines
("1G2D") may be used.
[0092] Referring to FIG. 9A, a circuit using one gate line and one
data line for one pixel ("1G1D") is used to apply different
voltages to the first and second solid pixel electrodes. In the
illustrated exemplary embodiment, a gate open (Von) voltage is
applied from one gate line Gn through switching elements T1, T2 and
T2, each data signal from one data line is applied, and then the
electrode voltage L-Pixel corresponding to the second solid pixel
electrode is controlled using additional Vcst voltage and liquid
crystal capacitors CLC-L and CLC_H. An electrode voltage H-Pixel
corresponding to the first solid pixel is applied. Thus, two
voltages different from each other may be applied to the first
solid pixel electrode and the second solid pixel electrode,
respectively.
[0093] Referring to FIG. 9B, a circuit using one gate line and two
data line for one pixel ("1G2D") is used to apply different
voltages to the first and second solid pixel electrodes. Each pixel
electrode is connected to a distinct data line, so that voltage may
be applied using distinct switching elements. A first switching
element PIXEL-A corresponding to the first solid pixel electrode,
and a second switching element PIXEL-B corresponding to the second
solid pixel electrode are respectively driven to apply the voltages
to the respective solid pixel electrode. The voltages are
controlled using liquid crystal capacitors CLC(A) and CLC(B), and
storage capacitors CST(A) and CST(B) connected to a storage
electrode line.
[0094] In an exemplary embodiment, a method of manufacturing a
display panel includes forming (e.g., providing) a common electrode
on a first substrate, forming one or more pixel electrodes on a
second substrate to form a unit pixel, injecting liquid crystal,
and pre-tilting the liquid crystal. The unit pixel includes a first
solid pixel electrode and a second solid pixel electrode. The
second solid pixel electrode is spaced apart from the first solid
pixel electrode and surrounds the first solid pixel electrode. The
first solid pixel electrode and the second solid pixel may include
a same material, and may be formed from a same layer of the display
panel. The first solid pixel electrode and the second solid pixel
may also be considered in or on a same layer of the display panel.
A typical method of manufacturing a display panel including forming
the common electrode and forming the pixel electrode on a substrate
may be used. However, when the unit pixel includes two pixel
electrodes and/or two pixel regions, in an operation for
pre-tilting of the liquid crystal, a specific manufacturing process
may be selected.
[0095] FIGS. 10A and 10B are cross-sectional views illustrating an
exemplary embodiment of forming liquid crystal having a pre-tilt
according to the invention.
[0096] Referring to FIGS. 10A and 10B, a method of manufacturing a
pre-tilt includes pre-tilting liquid crystal on a first solid pixel
electrode (first pre-tilt forming operation) and pre-tilting liquid
crystal on a second solid pixel electrode (second pre-tilt forming
operation). In exemplary embodiments of the invention, one unit
pixel includes solid pixel electrodes having different shapes from
each other. Arrangement of liquid crystal molecules of the liquid
crystal may be toward a center portion of the unit pixel.
[0097] Thus, after the first pre-tilt forming operation, the second
pre-tilt forming operation may be processed, so that liquid crystal
on the first solid pixel electrode may influence the pre-tilt of
liquid crystal on the second pixel electrode.
[0098] In the first pre-tilt forming operation, a voltage is
applied to the first solid pixel electrode to pre-tilt liquid
crystal. The pre-tilted liquid crystal may be formed by various
methods. In one exemplary embodiment, for example, in a process of
injecting liquid crystal, light-curing material may be mixed with
the liquid crystal. The light-curing material may be reactive
mesogen ("RM"). The light-curing material is injected, and a
voltage is applied to a common electrode and the first solid pixel
electrode, so that liquid crystal on the first solid pixel
electrode is tilted toward a center of a pixel electrode including
the first solid pixel electrode. After that, specific light such as
ultraviolet rays is irradiated to the liquid crystal mixed with the
light curing-material. Due to the irradiated light, the
light-curing material in the liquid crystal is hardened, so that
pre-tilted liquid crystal may be formed.
[0099] In addition or alternatively, a RM alignment layer may be
used. The RM alignment layer tilts or inclines liquid crystal
molecules on the RM alignment layer according to a direction of
light irradiation. The molecules which are inclined may form the
pre-tilted liquid crystal. The pre-tilt of the liquid crystal may
be formed by light irradiation without applying of a voltage. Thus,
the pre-tilt of liquid crystal may be formed by controlling a
direction of light irradiation without applying voltage to the
common electrode and the first solid pixel electrode.
[0100] Referring to FIG. 10A again, a common voltage Vcom is
applied to the common electrode 310 of the first substrate 300, and
a voltage is applied to a first solid pixel electrode 121 of the
second substrate 100 to form an electric field therebetween as
shown by the arrow, so that liquid crystal LB disposed at a
boundary of the first solid pixel electrode 121 may be arranged. A
portion of liquid crystal L1 on the first solid pixel electrode 121
may be influenced by the electric field and/or the tilted liquid
crystal LB, so that the portion of the liquid crystal L1 may be
tilted toward the center of the pixel electrode 110. With the
liquid crystal LB and L1 arranged and tilted as described above,
light is irradiated to the liquid crystal layer 200 to form the
pre-tilted liquid crystal of the first pre-tilt forming
operation.
[0101] In the second pre-tilt forming operation, a voltage, which
is lower than a voltage applied to the first solid pixel electrode
121, is applied to the second solid pixel electrode 123 to form
pre-tilted liquid crystal. Forming the pre-tilt in the first
pre-tilt forming operation may be substantially same as that of the
first pre-tilt forming operation. A difference between the first
pre-tilt forming operation and the second pre-tilt forming
operation is applying the voltage to the second solid pixel
electrode. A voltage is applied the first solid pixel electrode
121, and a voltage, which is lower than a voltage applied to the
first solid pixel electrode 121, is applied to the second solid
pixel electrode 123. An electric field formed between the second
solid pixel electrode 123 and the common electrode 310, and tilted
liquid crystal on the first solid pixel electrode 121 both
influence liquid crystal on the second solid pixel electrode 123,
so that liquid crystal on the second solid pixel electrode 123 is
arranged. After that, specific light such as ultraviolet rays is
irradiated to the liquid crystal. Due to the light, the
light-curing material in the liquid crystal is hardened, so that
pre-tilted liquid crystal may be formed.
[0102] Referring to FIG. 10B again, a common voltage Vcom is
applied to the common electrode 310 of the first substrate 300 and
voltages are applied to the first solid pixel electrode 121 and the
second solid pixel electrode 123 of the second substrate 100 to
form respective electric fields therebetween, so that liquid
crystal LB disposed at a boundary of the first solid pixel
electrode 121 and liquid crystal L2 disposed at an edge of the
second solid pixel electrode 123 may be arranged. By the peripheral
controlling portion 1232 adjacent to outer boundaries of the second
solid pixel electrode 123, the arrangement of liquid crystal L2 may
be regular and uniform.
[0103] Accordingly, liquid crystal L2 on the second solid pixel
electrode 123 is tilted toward the center of the pixel electrode.
With the liquid crystal L2 tilted, light is irradiated to form the
pre-tilt.
[0104] FIG. 11 is a graph illustrating a transmittance in percent
(%) of a display panel in accordance with an applied voltage in
volts (V), of an exemplary embodiment of the display panel
according to the invention.
[0105] Referring to FIG. 11, transmittance E1 of liquid crystal on
the first solid pixel electrode is different from transmittance E2
of liquid crystal on the second solid pixel electrode due to
applied voltages. The pre-tilt of the liquid crystal is formed by
voltages different from each other, so that transmittances of the
liquid crystal are differently distributed. If same voltage is
applied, then transmittance E1 of liquid crystal on the first solid
pixel electrode is relatively higher and reaches a maximum
transmittance (100%) faster than when the different voltages
applied.
[0106] FIGS. 12A to 12E are photographs illustrating a
transmittance of a unit pixel represented in FIG. 11.
[0107] Referring to FIGS. 12A to 12E, the photographs show
transmittance distributions of the unit pixel according to applied
voltages of FIG. 11. FIG. 12A is a transmittance distribution of
the unit pixel when a voltage corresponding to a first position P1
of FIG. 11 is applied. FIG. 12B is a transmittance distribution of
the unit pixel when a voltage corresponding to a second position P2
of FIG. 11 is applied. FIG. 12C is a transmittance distribution of
the unit pixel when a voltage corresponding to a third position P3
of FIG. 11 is applied. FIG. 12D is a transmittance distribution of
the unit pixel when a voltage corresponding to a fourth position P4
of FIG. 11 is applied. FIG. 12E is a transmittance distribution of
the unit pixel when a voltage corresponding to a fifth position P5
of FIG. 11 is applied.
[0108] As shown in FIGS. 12A to 12E, the unit pixel includes four
domains each having a transmittance distribution. Differences in
the transmittance difference are caused by different applied
voltages.
[0109] FIGS. 13A and 13B are graphs illustrating a transmittance
difference in arbitrary units (a.u.) in accordance with an applied
voltage in volts (V), with respect to a gap between solid pixel
electrodes.
[0110] Referring to FIG. 13A, differences in transmittance occur
when an error in the pixel gap between the first solid pixel
electrode and the second solid pixel electrode occurs, relating to
a reference value of the pixel gap. A first width d1 of the pixel
gap is 0.1 micrometer (.mu.m) smaller than the reference value, a
second width d2 of the pixel gap is same as the reference value,
and a third width d3 of the pixel gap is 0.1 .mu.m larger than the
reference value. A deviation from the reference value may be
considered an error in the pixel gap. As shown in FIG. 13A,
although the error in the pixel gap is made, transmittance may
hardly be influenced.
[0111] FIG. 13B is a graph showing transmittance difference in
region A of FIG. 13A.
[0112] Referring to FIG. 13B, although the error in the pixel gap
is made especially while the transmittance changes from 0 to
positive value, the transmittance may hardly be influenced by the
error. Thus, if an error in pixel gap is made during a
manufacturing process, transmittance of the pixel electrode may not
be changed.
[0113] According to one or more exemplary embodiment of the
invention, liquid crystal is arranged by an electric field formed
between a common electrode and a first solid pixel electrode, an
electric field formed between the common electrode and a second
solid pixel electrode, and an electric field formed between the
first solid pixel electrode and the second solid pixel electrode.
Thus, if an error in a pixel gap between the first solid pixel
electrode and the second solid pixel electrode is made,
transmittance may hardly be influenced. Therefore, display quality
of the one or more exemplary embodiment of the invention may be
improved, as compared to a conventional pixel structure using a
slit defined in a pixel electrode.
[0114] The foregoing is illustrative of the invention and is not to
be construed as limiting thereof. Although a few exemplary
embodiments of the invention have been described, those skilled in
the art will readily appreciate that many modifications are
possible in the exemplary embodiments without materially departing
from the novel teachings and advantages of the invention.
Accordingly, all such modifications are intended to be included
within the scope of the invention as defined in the claims. In the
claims, means-plus-function clauses are intended to cover the
structures described herein as performing the recited function and
not only structural equivalents but also equivalent structures.
Therefore, it is to be understood that the foregoing is
illustrative of the invention and is not to be construed as limited
to the specific exemplary embodiments disclosed, and that
modifications to the disclosed exemplary embodiments, as well as
other exemplary embodiments, are intended to be included within the
scope of the appended claims. The invention is defined by the
following claims, with equivalents of the claims to be included
therein.
* * * * *