U.S. patent application number 14/262767 was filed with the patent office on 2015-05-07 for method of attaching polarizing plate.
This patent application is currently assigned to Samsung Display Co., Ltd.. The applicant listed for this patent is Samsung Display Co., Ltd.. Invention is credited to Jihye KIM, Sangjae KIM, GwanYoung NA, SEUNGBEOM PARK.
Application Number | 20150126092 14/262767 |
Document ID | / |
Family ID | 52986912 |
Filed Date | 2015-05-07 |
United States Patent
Application |
20150126092 |
Kind Code |
A1 |
NA; GwanYoung ; et
al. |
May 7, 2015 |
METHOD OF ATTACHING POLARIZING PLATE
Abstract
An method of attaching a polarizing plate to a liquid crystal
display panel includes inspecting an alignment axis of the liquid
crystal display panel using an optical axis inspector; controlling
a position of the liquid crystal display panel with respect to a
reference alignment axis, according to a result of the inspecting
the alignment axis of the liquid crystal display panel; providing
the polarizing plate to the liquid crystal display panel at the
controlled position thereof; and attaching the polarizing plate to
the liquid crystal panel at the controlled position thereof.
Inventors: |
NA; GwanYoung; (Osan-si,
KR) ; KIM; Sangjae; (Seongnam-si, KR) ; KIM;
Jihye; (Hwaseong-si, KR) ; PARK; SEUNGBEOM;
(Hwaseong-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Display Co., Ltd. |
Yongin-City |
|
KR |
|
|
Assignee: |
Samsung Display Co., Ltd.
Yongin-City
KR
|
Family ID: |
52986912 |
Appl. No.: |
14/262767 |
Filed: |
April 27, 2014 |
Current U.S.
Class: |
445/24 |
Current CPC
Class: |
G02F 1/1303 20130101;
G02F 1/133528 20130101 |
Class at
Publication: |
445/24 |
International
Class: |
G02F 1/1335 20060101
G02F001/1335 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 5, 2013 |
KR |
10-2013-0133744 |
Claims
1. A method of attaching a polarizing plate to a liquid crystal
display panel, comprising: inspecting an alignment axis of liquid
crystals in the liquid crystal display panel using an optical axis
inspector; controlling a position of the liquid crystal display
panel with respect to a reference alignment axis, according to a
result of the inspecting the alignment axis of the liquid crystals
in the liquid crystal display panel; providing the polarizing plate
to the liquid crystal display panel at the controlled position
thereof; and attaching the polarizing plate to the liquid crystal
panel at the controlled position thereof.
2. The method of claim 1, wherein the polarizing plate is in roll
form, and the providing the polarizing plate comprises providing
the roll form polarizing plate to the liquid crystal display panel
at the controlled position thereof.
3. The method of claim 1, further comprising cutting the polarizing
plate after the attaching the polarizing plate, wherein the
polarizing plate comprises a first portion making contact with the
liquid crystal display panel at the controlled position thereof,
and a second portion except for the first portion, which does not
make contact with the liquid crystal display panel at the
controlled position thereof, and the second portion of the
polarizing plate is removed from a remaining portion of the
polarizing plate by the cutting the polarizing plate after the
attaching the polarizing plate.
4. The method of claim 3, wherein the removing the second portion
is performed by an optical tool.
5. The method of claim 1, further comprising removing bubbles
formed between the liquid crystal display panel and the polarizing
plate, after the attaching the polarizing plate.
6. The method of claim 1, further comprising inspecting a
transmission axis of the polarizing plate, using the optical axis
inspector, after the providing the polarizing plate.
7. The method of claim 1, further comprising inspecting the
polarizing plate for a defect, after the providing the polarizing
plate.
8. The method of claim 7, further comprising cutting the polarizing
plate along a widthwise direction of the liquid crystal display
panel, after the providing the polarizing plate.
9. The method of claim 7, further comprising cutting the polarizing
plate along a lengthwise direction of the liquid crystal display
panel, after the providing the polarizing plate.
10. The method of claim 1, further comprising inspecting the liquid
crystal display panel for a defect, before the inspecting the
alignment axis.
11. The method of claim 10, further comprising cleaning the liquid
crystal display panel, before the inspecting the liquid crystal
display panel for the defect.
12. The method of claim 1, wherein the controlling the position of
the liquid crystal display panel comprises rotating the liquid
crystal display panel in a direction opposite to a direction in
which the alignment axis of the liquid crystals in the liquid
crystal display panel is twisted with respect to the reference
alignment axis.
13. The method of claim 1, wherein the attaching the polarizing
plate attaches the polarizing plate to the liquid crystal display
panel such that the alignment axis of the liquid crystals in the
liquid crystal display panel is substantially perpendicular to a
transmission axis of the polarizing plate.
14. The method of claim 1, wherein the attaching the polarizing
plate attaches the polarizing plate to the liquid crystal display
panel such that the alignment axis of the liquid crystals in the
liquid crystal display panel is substantially parallel to a
transmission axis of the polarizing plate.
15. The method of claim 1, wherein the inspecting the alignment
axis of the liquid crystals in the liquid crystal display panel
comprises determining a twisted degree of the alignment axis of the
liquid crystals in the liquid crystal display panel, with respect
to the reference alignment axis.
16. The method of claim 15, wherein the controlling the position of
the liquid crystal display panel comprises rotating the liquid
crystal display panel in a direction opposite to a direction of the
twisted degree of the alignment axis of the liquid crystals in the
liquid crystal display panel with respect to the reference
alignment axis, after the inspecting the alignment axis of the
liquid crystals in the liquid crystal display panel, to define the
controlled position of the liquid crystal display panel.
17. The method of claim 16, wherein in the attaching the polarizing
plate to the liquid crystal panel at the defined controlled
position thereof, after the liquid crystal panel is rotated in the
direction opposite to the direction of the twisted degree of the
alignment axis of the liquid crystals in the liquid crystal display
panel, the alignment axis of the liquid crystals in the liquid
crystal display panel is aligned substantially parallel to or
perpendicular to a transmission axis of the polarizing plate.
Description
[0001] This application claims priority to Korean Patent
Application No. 10-2013-0133744, filed on Nov. 5, 2013, and all the
benefits accruing therefrom under 35 U.S.C. .sctn.119, the contents
of which are hereby incorporated by reference in its entirety.
BACKGROUND
[0002] 1. Field
[0003] The invention relates to a method of attaching a polarizing
plate. More particularly, the invention relates to a method of
attaching a polarizing plate to a liquid crystal display panel.
[0004] 2. Description of the Related Art
[0005] A liquid crystal display includes a liquid crystal display
panel and a pair of polarizing plates respectively disposed on
upper and lower sides of the liquid crystal display panel.
[0006] The liquid crystal display panel includes two transparent
substrates and a liquid crystal layer disposed between the two
substrates, and various liquid crystal modes are determined
depending on an arrangement and a liquid crystal phase of liquid
crystal molecules included in the liquid crystal layer.
[0007] A manufacturing process of the liquid crystal display
includes a process of attaching the polarizing plates to the liquid
crystal panel.
SUMMARY
[0008] One or more exemplary embodiment of the invention provides a
method of attaching a polarizing plate to a liquid crystal display
panel, to improve a contrast ratio of the liquid crystal display
panel.
[0009] An exemplary embodiment of the invention provides a method
of attaching a polarizing plate to a liquid crystal display panel,
including inspecting an alignment axis of the liquid crystal
display panel using an optical axis inspector, controlling a
position of the liquid crystal display panel with respect a
reference alignment axis according to a result of the inspecting
the alignment axis of the liquid crystal display panel, providing
the polarizing plate to the liquid crystal display panel at the
controlled position thereof, and attaching the polarizing plate to
the liquid crystal panel at the controlled position thereof.
[0010] In the inspecting the alignment axis of the liquid crystal
display panel, a twisted degree of an alignment axis of liquid
crystals included in the liquid crystal display panel with respect
to the reference alignment axis may be determined, using the
optical axis inspector.
[0011] In the controlling the position of the liquid crystal
display panel, the position of the liquid crystal display panel may
be controlled in accordance with the twisted degree of the
alignment axis using a rotator, after the inspecting the alignment
axis. Therefore, the polarizing plate is attached to the liquid
crystal display panel such that the alignment axis of the liquid
crystals included in the liquid crystal display panel is
substantially perpendicular to or in parallel to a transmission
axis of the polarizing plate.
[0012] According to one or more exemplary embodiment of the
invention, the polarizing plate is attached to the liquid crystal
display panel after the alignment axis of the liquid crystal
display panel is inspected and after the liquid crystal display
panel is rotated by the twisted degree of the alignment axis of the
liquid crystal display panel. Thus, the contrast ratio of the
liquid crystal display may be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above and other advantages of the disclosure will become
readily apparent by reference to the following detailed description
when considered in conjunction with the accompanying drawings, in
which:
[0014] FIG. 1 is a perspective view showing an exemplary embodiment
of a liquid crystal display;
[0015] FIG. 2 is an exploded perspective view taken along line I-I'
of FIG. 1;
[0016] FIG. 3 is a block diagram showing the liquid crystal display
of FIGS. 1 and 2;
[0017] FIG. 4 is view showing an exemplary embodiment of a black
mode in which a liquid crystal display displays a black color when
no electric field is applied to the liquid crystal display;
[0018] FIG. 5A is a plan view explaining a relationship between a
first alignment axis and a first transmission axis shown in FIG.
4;
[0019] FIG. 5B is a plan view explaining a relationship between a
second alignment axis and a second transmission axis shown in FIG.
4;
[0020] FIG. 6 is a schematic diagram showing an exemplary
embodiment of an apparatus for attaching a polarizing plate;
[0021] FIG. 7 is a flowchart showing an exemplary embodiment of a
method of attaching a polarizing plate according to the
invention;
[0022] FIG. 8A is a plan view showing an exemplary embodiment of a
twisted alignment axis of a liquid crystal display;
[0023] FIG. 8B is a plan view showing an exemplary embodiment of a
process of controlling a position of a liquid crystal display
panel;
[0024] FIG. 8C is a plan view for explaining an exemplary
embodiment of a process of attaching a polarizing plate to a liquid
crystal display panel; and
[0025] FIG. 9 is a flowchart showing another exemplary embodiment
of a method of attaching a polarizing plate according to the
invention.
DETAILED DESCRIPTION
[0026] It will be understood that when an element or layer is
referred to as being "on" or "connected to" another element or
layer, it can be directly on or connected to the other element or
layer or intervening elements or layers may be present. 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.
[0027] It will be understood that, although the terms first,
second, 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.
[0028] Spatially relative terms, such as "below", "lower", "above",
"upper" and the like, may be used herein for ease of description to
describe one element or feature's relationship 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" other elements or features would then be
oriented "above" 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.
[0029] 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 "includes" and/or "including", when used in this
specification, specify the presence of stated features, integers,
steps, 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.
[0030] 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.
[0031] 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.
[0032] Hereinafter, the invention will be explained in detail with
reference to the accompanying drawings.
[0033] FIG. 1 is a perspective view showing an exemplary embodiment
of a liquid crystal display and FIG. 2 is an exploded perspective
view taken along line I-I' of FIG. 1.
[0034] Referring to FIGS. 1 and 2, a liquid crystal display
includes a liquid crystal display panel LP, a first polarizing
plate POL1 disposed under the liquid crystal display panel LP, and
a second polarizing plate POL2 disposed on the liquid crystal
display panel LP.
[0035] The liquid crystal display panel LP includes a display area
DA in which an image is displayed, and a non-display area NDA
surrounding the display area DA. The liquid crystal display panel
LP includes a first substrate SUB1, a second substrate SUB2 facing
the first substrate SUB1, and liquid crystals LC interposed between
the first substrate SUB1 and the second substrate SUB2.
[0036] FIG. 3 is a block diagram showing the liquid crystal display
of FIGS. 1 and 2.
[0037] Referring to FIGS. 1 to 3, the first substrate SUB1 includes
a plurality of gate lines GL, a plurality of data lines DL arranged
to cross the gate lines GL, and a plurality of pixels PX connected
the gate lines GL and the data lines DL.
[0038] The gate lines GL extend in a first direction D1 and are
arranged substantially in parallel to each other. The data lines DL
extend in a second direction D2 to cross the gate lines GL and are
arranged substantially in parallel to each other.
[0039] Each pixel PX is connected to a corresponding gate line of
the gate lines GL and a corresponding data line of the data lines
DL, to display the image.
[0040] Each pixel PX includes a thin film transistor TFT, a liquid
crystal capacitor Clc, and a storage capacitor Cst.
[0041] Although not shown in the figures, the thin film transistor
TFT includes a gate electrode connected to the corresponding gate
line of the gate lines GL, a source electrode connected to the
corresponding data line of the data lines DL, and a drain electrode
connected to the liquid crystal capacitor Clc and the storage
capacitor Cst.
[0042] The liquid crystal capacitor Clc includes a pixel electrode
and a common electrode which are disposed on the first substrate
SUB1, as two terminals thereof, and the liquid crystals LC serve as
a dielectric substance. Here, the pixel electrode and the common
electrode are disposed on the first substrate SUB 1, but the
invention is not limited thereto or thereby. In an alternative
exemplary embodiment, the common electrode may be disposed on the
second substrate SUB2.
[0043] The pixel electrode is electrically connected to the drain
electrode of the thin film transistor TFT, and the common electrode
receives a reference voltage.
[0044] Each of the pixels PX may include a color filter (not shown)
disposed on the second substrate SUB2 to correspond to the pixel
electrode and to display one color of primary colors. Although not
shown in figures, the color filter may be disposed on or under the
pixel electrode disposed on the first substrate SUB1.
[0045] The liquid crystal display panel LP receives a light from a
backlight assembly BA and controls the light from the backlight
assembly BA in response to signals from a driving part to display
the image.
[0046] The driving part includes a timing controller TC, a gate
driver GD, and a data driver DD.
[0047] The data driver DD is connected to the data lines DL of the
liquid crystal display panel LP and applies data voltages
corresponding to image signals to the pixels PX.
[0048] Each of the gate driver GD and the data driver DD may
include a plurality of driving integrated circuit chips directly
mounted on the liquid crystal display panel LP or indirectly
attached to the liquid crystal display panel LP in a tape carrier
package ("TCP") form after being mounted on a flexible printed
circuit film. In addition, the gate driver GD and the data driver
DD may be directly integrated on the liquid crystal display panel
LP, for example, without integrated circuit chips or the TCP
form.
[0049] The timing controller TC receives image signals RGB and
control signals CS from an external source (not shown), such as a
vertical synchronization signal, a horizontal synchronization
signal, a clock signal, a data enable signal, etc., to control the
display of the image signals RGB. The timing controller TC
processes the image signals RGB by taking an operation condition of
the liquid crystal display panel LP into consideration in response
to the control signals CS and applies data signals DAT and a first
control signal CONT1 to the data driver DD. The timing controller
TC applies a second control signal CONT2 to the gate driver GD. The
first control signal CONT1 includes a clock signal, a polarity
inversion signal, and a line latch signal, and the second control
signal CONT2 includes a vertical synchronization start signal, an
output enable signal, and a gate pulse signal.
[0050] The data driver DD receives and sequentially shifts the data
signals DAT corresponding to the pixels PX arranged in one row in
response to the second control signal CONT1 from the timing
controller TC. The data driver DD applies data voltages
corresponding to the data signals to the data lines DL.
[0051] The gate driver GD applies a gate-on voltage to the gate
lines GL in response to the first control signal CONT2.
[0052] Accordingly, each of the pixels PX is turned on the gate-on
voltage and the turned-on pixel PX receives a corresponding data
voltage from the data driver DD, thereby displaying a desired
image.
[0053] Referring to FIG. 2 again, the liquid crystal display panel
LP includes a first alignment layer AL1 disposed on the first
substrate SUB1 and a second alignment layer AL2 disposed under the
second substrate SUB2 to face the first alignment layer AL1.
[0054] The liquid crystals LC are aligned in a predetermined
direction along the alignment axes of the first and second
alignment layers AL1 and AL2. In the illustrated exemplary
embodiment, for instance, the liquid crystals LC are aligned in a
second direction D2 on the first alignment layer AL1 having a first
alignment axis A1 extending in the second direction D2.
[0055] The liquid crystal display includes the first polarizing
plate POL1 disposed under the first substrate SUB1 and the second
polarizing plate POL2 disposed on (e.g., above) the second
substrate SUB2. Each of the first and second polarizing plates POL1
and POL2 have a transmission axis extended in one direction to
transmit the light from the backlight assembly BA in the one
direction. In the illustrated exemplary embodiment, for instance,
the second polarizing plate POL2 having a second transmission axis
P2 extending in the first direction D1 transmits only
linearly-polarized light in the first direction D1 among the light
incident thereto.
[0056] FIG. 4 is view showing an exemplary embodiment of a black
mode in which a liquid crystal display displays a black color when
no electric field is applied to the liquid crystal display.
[0057] Here, the arrangement of the liquid crystals LC in
accordance with the application of the electric field to the liquid
crystal display panel LP and the travel of the light will be
described in detail. FIG. 4 shows the black mode in which the
liquid crystal display panel LP displays the black color when the
electric field is not applied to the liquid crystal display panel
LP (hereinafter, referred to as inactivation state).
[0058] The first alignment layer AL1 has the first alignment axis
A1 in which the liquid crystals LC are aligned along a reference
alignment axis SA extending in the second direction D2. The second
alignment layer AL2 has a second alignment axis A2 in which the
liquid crystals LC are aligned along the reference alignment axis
SA extending in the second direction D2.
[0059] Each of the first and second alignment layers AL1 and AL2
may be a horizontal alignment layer, and the first alignment axis
A1 and the second alignment axis A2 may be substantially in
parallel to each other. Where the first and second alignment axes
A1 and A2 are parallel to each other, the liquid crystals LC are
aligned substantially in parallel to each other between the first
and second alignment layers AL1 and AL2 in the inactivation
state.
[0060] In the illustrated exemplary embodiment, the first and
second alignment axes A1 and A2 are substantially in parallel to
each other along the second direction D2, but the invention is not
limited thereto or thereby. That is, although not shown in figures,
the first alignment axis A1 and the second alignment axis A2 may be
substantially vertical (e.g., perpendicular) to each other. Where
the first and second alignment axes A1 and A2 are perpendicular to
each other, the liquid crystals LC are continuously twisted between
the first alignment layer AL1 and the second alignment layer
AL2.
[0061] Among the light from the backlight assembly BA incident on
the first polarizing plate POL1, only linearly-polarized light
substantially in parallel to the first transmission axis P1
transmits through the first polarizing plate POL1 and all other
light is absorbed by the first polarizing plate POL1. The
linearly-polarized light parallel to the first transmission axis P1
passes through the liquid crystals LC and then is absorbed by the
second polarizing plate POL2 having the second transmission axis P2
substantially vertical to the first transmission axis P1, thereby
displaying the black color.
[0062] FIG. 5A is a plan view explaining a relationship between the
first alignment axis and the first transmission axis shown in FIG.
4, and FIG. 5B is a plan view explaining a relationship between the
second alignment axis and the second transmission axis shown in
FIG. 4.
[0063] FIG. 5A shows a first group G1 including the first
polarizing plate POL1 and the first alignment layer AL1 shown in
FIG. 4 in a plan view (e.g., a top plan view) and FIG. 5B shows a
second group G2 including the second polarizing plate POL2 and the
second alignment layer AL2 shown in FIG. 4 in the plan view.
[0064] As shown in FIG. 5A, the first alignment axis A1 is
substantially in parallel to the reference alignment axis SA
extending in the second direction D2. In addition, the first
transmission axis P1 is substantially in parallel to the first
alignment axis A1.
[0065] As shown in FIG. 5B, the second alignment axis A2 is
substantially in parallel to the reference alignment axis SA
extending in the second direction D2. In addition, the second
transmission axis P2 is substantially perpendicular to the second
alignment axis A2.
[0066] Therefore, the liquid crystal display displays the black
color since the linearly-polarized light is absorbed by the second
polarizing plate POL2 having the second transmission axis P2
substantially perpendicular to the first transmission axis P1 after
passing through the first transmission axis P1 of the first
polarizing plate POL1.
[0067] When the electric field is formed in the liquid crystal
display in the black mode, the liquid crystals LC are twisted along
the electric field, e.g., dotted line liquid crystal LC in FIG. 4,
and thus a direction in which the linearly-polarized light travels
is changed and the linearly-polarized light transmits through the
second polarizing plate POL2. Thus, a gray scale of the liquid
crystal display is changed and the image is displayed.
[0068] In the illustrated exemplary embodiment, the liquid crystal
display of the black mode has been described as a representative
example, but the above-mentioned operation may be realized by a
liquid crystal display in a white mode to which the electric field
is applied. Where the direction in which the linearly-polarized
light travels in the white mode is changed and the
linearly-polarized light transmits through the second polarizing
plate POL2, the first transmission axis P1 and the second
transmission axis P2 are substantially in parallel to each
other.
[0069] In the illustrated exemplary embodiment, the liquid crystal
display is operated in a plane-to-switching ("PLS") mode in which
the pixel electrode and the common electrode are both disposed
within the first substrate SUB1, but the invention is not limited
thereto or thereby.
[0070] As described above, a display quality of the liquid crystal
display is determined depending on the relationship between the
alignment axes of the alignment layers and the transmission axes of
the polarizing plates. Accordingly, when the liquid crystal display
is manufactured, the alignment axes and the transmission axes are
required to form an angle appropriate to the driving mode of the
liquid crystal display.
[0071] Hereinafter, an exemplary embodiment of a method of
attaching a polarizing plate to a liquid crystal display panel and
an apparatus therefor, will be described in detail.
[0072] FIG. 6 is a schematic diagram showing an exemplary
embodiment of an apparatus which attaches a polarizing plate.
[0073] Referring to FIG. 6, the apparatus for attaching the
polarizing plate includes an alignment axis inspection part 100
configured to inspect the alignment axis of the liquid crystal
display panel, a position control part 200 configured to control a
position of the liquid crystal display panel according to the
result of inspecting the alignment axis, a polarizing plate
provider 300 configured to provide the polarizing plate to a liquid
crystal display panel, a polarizing plate attaching part 400
configured to attach the polarizing plate to the liquid crystal
display panel, and a cutting part 500 configured to cut the
polarizing plate.
[0074] FIG. 7 is a flowchart showing an exemplary embodiment of a
method of attaching a polarizing plate.
[0075] Referring to FIG. 7, the method of attaching the polarizing
plate includes inspecting the alignment axis (S100), controlling
the position of the liquid crystal display panel (S200), providing
the polarizing plate to the liquid crystal display panel (S300),
attaching the polarizing plate to the liquid crystal display (S400)
and cutting the polarizing plate (S500).
[0076] In the inspecting the alignment axis (S100), a twisted
degree of the alignment axis of liquid crystals aligned in the
liquid crystal display panel with respect to the reference
alignment axis, is determined, such as by using an optical axis
inspector.
[0077] The optical axis inspector may include a lamp to inspect the
alignment axis. The light emitted from the lamp is irradiated to
the liquid crystal display panel. Accordingly, the optical axis
inspector may calculate the twisted degree of the alignment axis
with respect to the reference alignment axis. The optical axis
inspector may include a sensor in addition to the lamp, but the
invention is not limited thereto or thereby, as long as the optical
axis inspector can determine and calculate the twisted angle of the
alignment axis.
[0078] FIG. 8A is a plan view showing an exemplary embodiment of a
twisted alignment axis of the liquid crystal display.
[0079] As shown in FIG. 8A, the twisted angle .theta. of the
alignment axis A of the liquid crystals aligned in the liquid
crystal display panel LP with respect to the reference alignment
axis SA extending in the second direction D2, may be measured by
the optical axis inspector.
[0080] Referring to FIG. 7 again, after the inspecting the
alignment axis (S100), the position of the liquid crystal display
panel is controlled in accordance with the twisted angle .theta.,
such as by using a rotating part, in the controlling of the
position (S200).
[0081] FIG. 8B is a plan view showing an exemplary embodiment of a
process of controlling the position of the liquid crystal display
panel.
[0082] As shown in FIG. 8B, the rotation part rotates the liquid
crystal display panel LP in a direction opposite to the twisted
direction of the alignment axis A. Referring to FIG. 8A, since the
alignment axis A is twisted in a clockwise direction from the
reference alignment axis SA, the liquid crystal display panel LP is
rotated in a counterclockwise direction (indicated by the curved
arrow), such that the alignment axis A becomes substantially
parallel to the reference alignment axis SA.
[0083] Referring to FIG. 7 again, the polarizing plate is provided
to the liquid crystal display panel LP in the providing the
polarizing plate (S300). The polarizing plate may be in a roll
form, such as being wrapped around a core or cylinder, in the
providing the polarizing plate (S300).
[0084] When the polarizing plate is provided onto the liquid
crystal display panel LP, the polarizing plate is attached to the
liquid crystal display panel LP, such as by using a roller in the
attaching the polarizing plate (S400).
[0085] FIG. 8C is a plan view explaining an exemplary embodiment of
a process of attaching the polarizing plate to the liquid crystal
display panel.
[0086] As shown in FIG. 8C, the polarizing plate POL having the
transmission axis P in the first direction D1 which has been
provided onto the liquid crystal display panel LP, is and attached
to the liquid crystal display panel LP that has been rotated
(S400). Thus, the transmission axis P is substantially
perpendicular to the alignment axis A of the liquid crystals
aligned in the liquid crystal display panel LP. In the providing
the polarizing plate POL to the liquid crystal display panel LP,
the transmission axis of the polarizing plate POL may be oriented
with respect to the reference alignment axis SA, and since the
liquid crystal display panel LP has been rotated with respect to
the reference alignment axis SA, the transmission axis of the
polarizing plate POL and the alignment axis of the liquid crystal
display panel LP may then be oriented with respect to each
other.
[0087] Here, the polarizing plate POL has the transmission axis P
in the first direction D1, but the invention is not limited thereto
or thereby. In an alternative exemplary embodiment, the polarizing
plate POL may have the transmission axis P in the second direction
D2 and may be attached to the liquid crystal display panel LP such
that the transmission axis P is substantially in parallel to the
alignment axis A of the liquid crystals aligned in the liquid
crystal display panel LP.
[0088] When the polarizing plate POL is attached to the rotated
liquid crystal display panel LP, the polarizing plate POL includes
a first portion AR1 making contact with the liquid crystal display
panel LP and a second portion AR2 except for the first portion AR1,
which does not make contact with the liquid crystal display panel
LP.
[0089] Referring to FIG. 7 again, the second portion AR2 of the
polarizing plate POL may be removed from a remainder of the
polarizing plate POL, such as by being cut away from the polarizing
plate POL using an optical tool, e.g., a laser beam generator, in
the cutting the polarizing plate (S500).
[0090] A portion of the liquid crystal display panel LP may be
exposed by the first portion AR1 of the polarizing plate POL making
contact with the liquid crystal display panel LP. The exposed
portion of the liquid crystal display panel LP may correspond to
the non-display area NDA of the liquid crystal display, such that
material of the polarizing plate POL is omitted in the non-display
area NDA.
[0091] FIG. 9 is a flowchart showing another exemplary embodiment
of a method of attaching a polarizing plate according to the
invention.
[0092] In the following description of the method of attaching the
polarizing plate according to the invention illustrated in FIG. 9,
different points from the above-mentioned method of attaching the
polarizing plate illustrated in FIG. 7-8C will be mainly
described.
[0093] Referring to FIG. 9, the method of attaching the polarizing
plate to the liquid crystal display panel includes inspecting the
alignment axis of the liquid crystal display panel (S100),
controlling the position of the liquid crystal display panel
(S200), providing the polarizing plate to the liquid crystal
display panel (S300), attaching the polarizing plate to the liquid
crystal display (S400) and cutting the polarizing plate (S500).
[0094] In addition, the method of attaching the polarizing plate
may further include cleaning the liquid crystal display panel (S10)
and inspecting the liquid crystal display panel for foreign matter
or a defect on the liquid crystal display panel (S20), which are
performed before the inspecting the alignment axis of the liquid
crystal display panel (S100)
[0095] Further, the method of attaching the polarizing plate may
further include inspecting the polarizing plate for foreign matter
or a defect on the polarizing plate (S310), inspecting the
transmission axis of the polarizing plate (S320), and cutting the
polarizing plate by taking the width and/or the length of the
liquid crystal display panel (S330) into consideration, which are
performed before the polarizing plate is attached to the liquid
crystal display panel (S400).
[0096] In the inspecting the transmission axis (S320), a twisted
degree of the transmission axis of the polarizing plate with
respect to a reference transmission axis is calculated, such as by
using the optical axis inspector. Accordingly, the position of the
liquid crystal display panel may be controlled in consideration of
the twisted degree of the transmission axis in the controlling the
position of the liquid crystal display panel (S200).
[0097] In the cutting the polarizing plate (S330), a portion of the
polarizing plate which will not overlap the liquid crystal display
panel, may be removed such as by cutting, before the polarizing
plate is attached to the liquid crystal display panel (S400). The
portion of the polarizing plate which is removed, may be calculated
in consideration of the twisted degree of the transmission axis
(S320) and the twisted degree of the alignment axis of liquid
crystals aligned in the liquid crystal display panel (S100).
[0098] The method of attaching the polarizing plate may further
include removing bubbles formed between the polarizing plate and
the liquid crystal display panel (S600) after the attaching the
polarizing plate to the liquid crystal display panel (S400). In an
exemplary embodiment of the removing the bubbles (S600), the
bubbles are removed by controlling a temperature and/or a pressure
in processes during or after the attaching the polarizing plate to
the liquid crystal display panel, and thus the polarizing plate may
be adhered to the liquid crystal display panel without bubbles
therebetween.
[0099] The removing the bubbles (S600) may be performed after or
before the cutting the polarizing plate (S500).
[0100] In one or more exemplary embodiment described above, when
the polarizing plate is attached to the liquid crystal display
panel using the method of attaching the polarizing plate according
to the invention, a method of reducing the tolerance between the
alignment axis and the transmission axis is as follows.
[0101] The following Table 1 shows a light leakage degree in
accordance with the angle (degrees: .degree.) of the alignment axis
and the angle (degrees: .degree.) of the transmission axis in a
black state of the PLS mode liquid crystal display.
TABLE-US-00001 TABLE 1 Angle of alignment axis (.degree.) -0.5 -0.4
-0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 Angle of -0.5 246 219 195 176
160 148 139 135 134 137 144 transmission -0.4 219 194 172 154 141
130 124 122 123 128 137 axis (.degree.) -0.3 195 172 153 137 125
117 113 113 116 123 134 -0.2 176 154 137 123 114 108 105 107 113
122 135 -0.1 160 141 125 114 106 102 102 105 113 124 139 0 148 131
117 108 102 100 102 108 117 131 148 0.1 139 124 113 105 102 102 106
114 125 141 160 0.2 135 122 113 107 105 108 114 123 137 154 176 0.3
134 123 116 113 113 117 125 137 153 172 195 0.4 137 128 123 122 124
130 141 154 172 194 219 0.5 144 137 134 135 139 148 160 176 195 219
246
[0102] In detail, Table 1 represents the light leakage degree
according to the angle difference between each alignment axis and
each transmission axis in percentages (%) on the assumption that
the light leakage degree is a reference light leakage (100%) when
the angle of the alignment axis against the reference alignment
axis is zero)(0.degree.) and the angle of the transmission axis
against the reference transmission axis is zero)(0.degree.).
[0103] Here, when the angle of the alignment axis is maintained at
zero)(0.degree.), the light leakage may be reduced in the black
state even though an error in the transmission axis is considered.
Therefore, the contrast ratio of the liquid crystal display may be
improved.
[0104] In one or more exemplary embodiment, the twisted degree of
the alignment axis may be calculated by inspecting the alignment
axis of the liquid crystal display panel before the polarizing
plate is attached to the liquid crystal display panel. Since the
polarizing plate is attached to the liquid crystal display panel
after the position of the liquid crystal display panel is
controlled in accordance with the calculated twisted degree of the
alignment axis, the alignment axis of the liquid crystal display
panel and the transmission axis of the polarizing plate are
maintained at a uniform angle. As a result, the contrast ratio of
the liquid crystal display may be improved. In addition, defects of
the liquid crystal display, which are generated in manufacturing of
the liquid crystal display, may be reduced.
[0105] Although exemplary embodiments of the invention have been
described, it is understood that the invention should not be
limited to these exemplary embodiments but various changes and
modifications can be made by one ordinary skilled in the art within
the spirit and scope of the invention as hereinafter claimed.
* * * * *