U.S. patent application number 15/826015 was filed with the patent office on 2018-03-22 for optical film, manufacturing method thereof, and display device.
The applicant listed for this patent is SAMSUNG ELECTRONICS CO., LTD., SAMSUNG SDI CO., LTD.. Invention is credited to Hyun-Seok CHOI, Sang ah GAM, Myung Sup JUNG, Hyung Jun KIM, Hye Young KONG.
Application Number | 20180081102 15/826015 |
Document ID | / |
Family ID | 54930270 |
Filed Date | 2018-03-22 |
United States Patent
Application |
20180081102 |
Kind Code |
A1 |
GAM; Sang ah ; et
al. |
March 22, 2018 |
OPTICAL FILM, MANUFACTURING METHOD THEREOF, AND DISPLAY DEVICE
Abstract
An optical film includes a polarization film including a polymer
resin and a dichroic dye, and a phase delay layer disposed on the
polarization film and including a liquid crystal.
Inventors: |
GAM; Sang ah; (Seoul,
KR) ; KONG; Hye Young; (Uijeongbu-si, KR) ;
KIM; Hyung Jun; (Suwon-si, KR) ; CHOI; Hyun-Seok;
(Anyang-si, KR) ; JUNG; Myung Sup; (Seongnam-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRONICS CO., LTD.
SAMSUNG SDI CO., LTD. |
Suwon-si
Yongin-si |
|
KR
KR |
|
|
Family ID: |
54930270 |
Appl. No.: |
15/826015 |
Filed: |
November 29, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14751482 |
Jun 26, 2015 |
9835780 |
|
|
15826015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02F 2001/133638
20130101; G02F 2001/133637 20130101; B32B 2309/105 20130101; B32B
37/025 20130101; G02F 2001/133541 20130101; B32B 2457/202 20130101;
G02B 5/3016 20130101; G02F 1/13363 20130101; G02B 5/3033
20130101 |
International
Class: |
G02B 5/30 20060101
G02B005/30; G02F 1/13363 20060101 G02F001/13363; B32B 37/00
20060101 B32B037/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2014 |
KR |
10-2014-0080188 |
Jun 22, 2015 |
KR |
10-2015-0088237 |
Claims
1. An optical film comprising: a polarization film; and an
anisotropic liquid crystal layer disposed on the polarization film,
wherein the anisotropic liquid crystal layer comprises a first
anisotropic liquid crystal layer and a second anisotropic liquid
crystal layer having different retardation from each other, and the
first anisotropic liquid crystal layer and the second anisotropic
liquid crystal layer has a refractive index satisfying the
following relationship, respectively: n.sub.x>n.sub.y=n.sub.z,
wherein n.sub.x denotes a refractive index of the first or second
anisotropic liquid crystal layer at a slow axis thereof, n.sub.y
denotes a refractive index of the first or second anisotropic
liquid crystal layer at a fast axis thereof, and n.sub.z denotes a
refractive index of the first or second anisotropic liquid crystal
layer in a direction perpendicular to the fast and slow axes
thereof.
2. The optical film of claim 1, wherein entire in-plane phase
retardation (R.sub.e0) of the first anisotropic liquid crystal
layer and the second anisotropic liquid crystal layer for 450 nm,
550 nm, and 650 nm wavelengths satisfies the following inequality:
R.sub.e0 (450 nm).ltoreq.R.sub.e0 (550 nm)<R.sub.e0 (650 nm) or
R.sub.e0 (450 nm)<R.sub.e0 (550 nm).ltoreq.R.sub.e0 (650
nm).
3. The optical film of claim 2, wherein the first anisotropic
liquid crystal layer and the second anisotropic liquid crystal
layer have entire short wavelength dispersion in a range from about
0.70 to about 0.99, and the first anisotropic liquid crystal layer
and the second anisotropic liquid crystal layer have entire long
wavelength dispersion in a range from about 1.01 to about 1.20.
4. The optical film of claim 1, wherein entire in-plane phase
retardation (R.sub.e0) of the first anisotropic liquid crystal
layer and the second anisotropic liquid crystal layer for 550 nm
wavelength is in a range from about 120 nm to about 160 nm.
5. The optical film of claim 1, wherein the first anisotropic
liquid crystal layer is a .lamda./2 phase delay layer, and the
second anisotropic liquid crystal layer is a .lamda./4 phase delay
layer.
6. The optical film of claim 1, wherein in-plane phase retardation
(R.sub.e1) of the first anisotropic liquid crystal layer for 450
nm, 550 nm and 650 nm wavelengths satisfies the following
inequality: R.sub.e1 (450 nm)>R.sub.e1 (550 nm)>R.sub.e1 (650
nm), in-plane phase retardation (Re.sub.2) of the second
anisotropic liquid crystal layer for 450 nm, 550 nm and 650 nm
wavelengths satisfies the following inequality: Re.sub.2 (450
nm)>R.sub.e2 (550 nm)>R.sub.e2 (650 nm), and entire in-plane
phase retardation (R.sub.e0) of the first anisotropic liquid
crystal layer and the second anisotropic liquid crystal layer for
450 nm, 550 nm and 650 nm wavelengths satisfies the following
inequality: R.sub.e0 (450 nm).ltoreq.R.sub.e0 (550 nm)<R.sub.e0
(650 nm) or R.sub.e0 (450 nm)<R.sub.e0 (550 nm).ltoreq.R.sub.e0
(650 nm).
7. The optical film of claim 6, wherein the first anisotropic
liquid crystal layer and the second anisotropic liquid crystal
layer each have short wavelength dispersion in a range from about
1.1 to about 1.2, and the first anisotropic liquid crystal layer
and the second anisotropic liquid crystal layer have entire short
wavelength dispersion in a range from about 0.70 to about 0.99.
8. The optical film of claim 6, wherein the first anisotropic
liquid crystal layer and the second anisotropic liquid crystal
layer each have long wavelength dispersion in a range from about
0.9 to about 1.0, and the first anisotropic liquid crystal layer
and the second anisotropic liquid crystal layer have entire long
wavelength dispersion in a range from about 1.01 to about 1.20.
9. The optical film of claim 6, wherein in-plane phase retardation
(R.sub.e1) of the first anisotropic liquid crystal layer for 550 nm
wavelength is in a range from about 230 nm to about 270 nm,
in-plane phase retardation (Re.sub.2) of the second anisotropic
liquid crystal layer for 550 nm wavelength is in a range from about
100 nm to about 140 nm, and entire in-plane phase retardation
(R.sub.e0) of the first anisotropic liquid crystal layer and the
second anisotropic liquid crystal layer for 550 nm wavelength is in
a range from about 120 nm to about 160 nm.
10. The optical film of claim 6, wherein an angle between a slow
axis of the first anisotropic liquid crystal layer and a slow axis
of the second anisotropic liquid crystal layer is in a range from
about 50 degrees to about 70 degrees.
11. The optical film of claim 6, further comprising: an adhesion
layer disposed between the first anisotropic liquid crystal layer
and the second anisotropic liquid crystal layer.
12. The optical film of claim 1, wherein the polarization film
comprises a polymer resin and a dichroic dye.
13. The optical film of claim 12, wherein the polymer resin
comprises a polyolefin, a polyamide, a polyester, a polyacryl,
polystyrene, a copolymer thereof, or a combination thereof.
14. The optical film of claim 12, wherein the polarization film
comprises a melt blend of the polymer resin and the dichroic
dye.
15. The optical film of claim 1, further comprising: an adhesion
layer disposed between the polarization film and the anisotropic
liquid crystal layer.
16. The optical film of claim 1, wherein the polarization film has
a thickness less than or equal to about 100 .mu.m and the
anisotropic liquid crystal layer has a thickness less than or equal
to about 10 .mu.m.
17. A display device including the optical film of claim 1.
18. A method of manufacturing an optical film, the method
comprising: melt-blending a polymer resin and a dichroic dye to
prepare a polarization film; preparing an anisotropic liquid
crystal layer on a substrate; and providing the anisotropic liquid
crystal layer on the polarization film, wherein the anisotropic
liquid crystal layer comprises a first anisotropic liquid crystal
layer and a second anisotropic liquid crystal layer, the first and
second anisotropic liquid crystal layers having different
retardation from each other, the first anisotropic liquid crystal
layer and the second anisotropic liquid crystal layer has a
refractive index satisfying the following relationship,
respectively: n.sub.x>n.sub.y=n.sub.z, wherein n.sub.x denotes a
refractive index of the first or second anisotropic liquid crystal
layer at a slow axis thereof, n.sub.y denotes a refractive index of
the first or second anisotropic liquid crystal layer at a fast axis
thereof, and n.sub.z denotes a refractive index of the first or
second anisotropic liquid crystal layer in a direction
perpendicular to the fast and slow axes thereof.
19. The method of claim 18, wherein the providing the anisotropic
liquid crystal layer on the polarization film comprises: removing
the anisotropic liquid crystal layer from the substrate; and
transferring the anisotropic liquid crystal layer to a surface of
the polarization film.
20. The method of claim 18, wherein the preparing the anisotropic
liquid crystal layer comprises stacking the first and second
anisotropic liquid crystal layers on the substrate, the first
anisotropic liquid crystal layer being a .lamda./2 phase delay
layer and the second anisotropic liquid crystal layer being a
.lamda./4 phase delay layer.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/751,482, filed on Jun. 26, 2015, which
claims priorities to Korean Patent Application Nos. 10-2014-0080188
and 10-2015-0088237 filed on Jun. 27, 2014 and Jun. 22, 2015, and
all the benefits accruing therefrom under 35 U.S.C. .sctn. 119, the
content of which in its entirety is herein incorporated by
reference.
BACKGROUND
1. Field
[0002] The disclosure relates to an optical film, a manufacturing
method thereof, and a display device including the optical
film.
2. Description of the Related Art
[0003] Commonly used flat panel displays may be classified into a
light-emitting display device that emits light by itself and a
non-emissive display device that includes a separate light source,
and an optical or compensation film such as a retardation film is
typically employed for improving the image quality thereof.
[0004] In the case of the light emitting display device, for
example, an organic light emitting display, the visibility and the
contrast ratio may be deteriorated by reflection of external light
caused by a metal such as an electrode. In the light emitting
display device, the linear polarized light is shifted into
circularly polarized light using a polarizing plate and a
retardation film to reduce such reflection of external light, such
that reflection of the external light by the organic light emitting
display and leakage thereof to the outside may be effectively
prevented.
[0005] In the liquid crystal display ("LCD"), which is the
non-emissive display device, the linear polarized light is changed
into the circularly polarized light to improve the image quality by
reducing the external light reflection, based on the type of
device, such as transparent type LCD, transflective type LCD,
reflective type LCD, and so on.
[0006] However, a conventional optical film used in a flat panel
display typically has weak optical durability and has an effect on
display quality, and has a thick thickness.
SUMMARY
[0007] An exemplary embodiment of the invention provides an optical
film having improved optical durability and optical characteristics
and a thin thickness.
[0008] Another exemplary embodiment provides a method of
manufacturing the optical film.
[0009] Yet another exemplary embodiment provides a display device
including the optical film.
[0010] According to an exemplary embodiment, an optical film
includes a polarization film including a polymer resin and a
dichroic dye, and a phase delay layer disposed on the polarization
film and including a liquid crystal.
[0011] In an exemplary embodiment, in-plane phase retardation
(R.sub.e0) of the phase delay layer for 450 nanometers (nm), 550 nm
and 650 nm wavelengths may satisfy the following inequality:
R.sub.e0 (450 nm).ltoreq.R.sub.e0 (550 nm)<R.sub.e0 (650 nm) or
R.sub.e0 (450 nm)<R.sub.e0 (550 nm).ltoreq.R.sub.e0 (650
nm).
[0012] In an exemplary embodiment, the phase delay layer may have
short wavelength dispersion in a range from about 0.70 to about
0.99, and the phase delay layer may have long wavelength dispersion
in a range from about 1.01 to about 1.20.
[0013] In an exemplary embodiment, in-plane phase retardation
(R.sub.e0) of the phase delay layer for 550 nm wavelength may be in
a range from about 120 nm to about 160 nm.
[0014] In an embodiment, the phase delay layer may include a first
phase delay layer and a second phase delay layer, the first and
second phase delay layers may have different retardation from each
other, and each of the first and second phase delay layers may
include liquid crystal.
[0015] In an exemplary embodiment, the first phase delay layer may
be a .lamda./2 phase delay layer, and the second phase delay layer
may be a .lamda./4 phase delay layer.
[0016] In an exemplary embodiment, the first phase delay layer and
the second phase delay layer may each have a refractive index
satisfying the following relationship: n.sub.x>n.sub.y=n.sub.z
or n.sub.x<n.sub.y=n.sub.z, where n.sub.x denotes a refractive
index of the first or second phase delay layer at a slow axis
thereof, n.sub.y denotes a refractive index of the first or second
phase delay layer at a fast axis thereof, and n.sub.z denotes a
refractive index of the first or second phase delay layer in a
direction perpendicular to the slow and fast axes thereof.
[0017] In an exemplary embodiment, in-plane phase retardation
(R.sub.e1) of the first phase delay layer for 450 nm, 550 nm and
650 nm wavelengths may satisfy the following inequality: R.sub.e1
(450 nm)>R.sub.e1 (550 nm)>R.sub.e1 (650 nm), in-plane phase
retardation (R.sub.e2) of the second phase delay layer for 450 nm,
550 nm and 650 nm wavelengths may satisfy the following inequality:
R.sub.e2 (450 nm)>R.sub.e2 (550 nm)>R.sub.e2 (650 nm), and
entire in-plane phase retardation (R.sub.e0) of the first phase
delay layer and the second phase delay layer for 450 nm, 550 nm and
650 nm wavelengths may satisfy the following inequality: R.sub.e0
(450 nm).ltoreq.R.sub.e0 (550 nm)<R.sub.e0 (650 nm) or R.sub.e0
(450 nm)<R.sub.e0 (550 nm).ltoreq.R.sub.e0 (650 nm).
[0018] In an exemplary embodiment, the first phase delay layer and
the second phase delay layer may each have short wavelength
dispersion in a range from about 1.1 to about 1.2, and the first
phase delay layer and the second phase delay layer may have entire
short wavelength dispersion in a range from about 0.70 to about
0.99.
[0019] In an exemplary embodiment, the first phase delay layer and
the second phase delay layer may each have long wavelength
dispersion in a range from about 0.9 to about 1.0, and the first
phase delay layer and the second phase delay layer may have entire
long wavelength dispersion in a range from about 1.01 to about
1.20.
[0020] In an exemplary embodiment, in-plane phase retardation
(R.sub.e1) of the first phase delay layer for 550 nm wavelength may
be in a range from about 230 nm to about 270 nm, in-plane phase
retardation (R.sub.e2) of the second phase delay layer for 550 nm
wavelength may be in a range from about 100 nm to about 140 nm, and
entire in-plane phase retardation (R.sub.e0) of the first phase
delay layer and the second phase delay layer for 550 nm wavelength
may be in a range from about 120 nm to about 160 nm.
[0021] In an embodiment, an angle between a slow axis of the first
phase delay layer and a slow axis of the second phase delay layer
may be in a range from about 50 degrees to about 70 degrees.
[0022] In an exemplary embodiment, the optical film may further
include an adhesion layer disposed between the first phase delay
layer and the second phase delay layer.
[0023] In an exemplary embodiment, the phase delay layer may have a
thickness less than or equal to about 10 micrometers (.mu.m).
[0024] In an exemplary embodiment, the optical film may further
include an adhesion layer disposed between the polarization film
and the phase delay layer.
[0025] In an exemplary embodiment, the polymer resin may include a
polyolefin, a polyamide, a polyester, a polyacryl, polystyrene, a
copolymer thereof, or a combination thereof.
[0026] In an exemplary embodiment, the polymer resin may include
polyethylene (PE), polypropylene (PP), polyethylene terephthalate
(PET), polyethylene terephthalate glycol (PETG), polyethylene
naphthalate (PEN), nylon, a copolymer thereof, or a combination
thereof.
[0027] In an exemplary embodiment, the polarization film may have a
thickness less than or equal to about 100 .mu.m.
[0028] In an exemplary embodiment, the polarization film may
include a melt blend of the polymer resin and the dichroic dye.
[0029] In an exemplary embodiment, a transparent substrate may not
be present between the polarization film and the phase delay
layer.
[0030] According to another exemplary embodiment, a display device
including an optical film described above.
[0031] According to another exemplary embodiment, a method of
manufacturing an optical film includes melt-blending a polymer
resin and a dichroic dye to prepare a polarization film, preparing
a phase delay layer including liquid crystal on a substrate, and
providing the phase delay layer on the polarization film.
[0032] In an exemplary embodiment, the providing the phase delay
layer on the polarization film may include removing the phase delay
layer from the substrate and transferring it to a surface of the
polarization film.
[0033] In an exemplary embodiment, the manufacturing method may
further include providing an adhesion layer on a surface of the
polarization film.
[0034] In an exemplary embodiment, the preparing the phase delay
layer may include stacking a .lamda./2 phase delay layer and a
.lamda./4 phase delay layer on the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The above and other features of the invention will become
more apparent by describing in further detail exemplary embodiments
thereof with reference to the accompanying drawings, in which:
[0036] FIG. 1 is a schematic cross-sectional view of an exemplary
embodiment of an optical film according to the invention;
[0037] FIG. 2 is a schematic view showing the external light
anti-reflection principle of an exemplary embodiment of an optical
film according to the invention;
[0038] FIG. 3 is a schematic view of an exemplary embodiment of a
polarization film according to the invention;
[0039] FIG. 4 is a schematic view of an alternative exemplary
embodiment of an optical film according to the invention;
[0040] FIG. 5 is a schematic cross-sectional view of an exemplary
embodiment of an organic light emitting display according to the
invention; and
[0041] FIG. 6 is a schematic cross-sectional view of a liquid
crystal display ("LCD") device according to the invention.
DETAILED DESCRIPTION
[0042] The invention now will be described more fully hereinafter
with reference to the accompanying drawings, in which various
embodiments are shown. This invention may, however, be embodied in
many different forms, and should not be construed as limited to the
embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure will be thorough and complete, and
will fully convey the scope of the invention to those skilled in
the art. Like reference numerals refer to like elements
throughout.
[0043] It will be understood that when an element is referred to as
being "on" another element, it can be directly on the other element
or intervening elements may be present therebetween. In contrast,
when an element is referred to as being "directly on" another
element, there are no intervening elements present.
[0044] 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
element, component, 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 herein.
[0045] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting. As
used herein, the singular forms "a," "an," and "the" are intended
to include the plural forms, including "at least one," unless the
content clearly indicates otherwise. "Or" means "and/or." As used
herein, the term "and/or" includes any and all combinations of one
or more of the associated listed items. It will be further
understood that the terms "comprises" and/or "comprising," or
"includes" and/or "including" when used in this specification,
specify the presence of stated features, regions, integers, steps,
operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, regions,
integers, steps, operations, elements, components, and/or groups
thereof.
[0046] Spatially relative terms, such as "beneath," "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" or "beneath" 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.
[0047] "About" or "approximately" as used herein is inclusive of
the stated value and means within an acceptable range of deviation
for the particular value as determined by one of ordinary skill in
the art, considering the measurement in question and the error
associated with measurement of the particular quantity (i.e., the
limitations of the measurement system). For example, "about" can
mean within one or more standard deviations, or within .+-.30%,
20%, 10%, 5% of the stated value.
[0048] 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
disclosure 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 the present
disclosure, and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0049] Exemplary embodiments are described herein with reference to
cross section illustrations that are schematic illustrations of
idealized embodiments. 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 described
herein should not be construed as limited to the particular shapes
of regions as illustrated herein but are to include deviations in
shapes that result, for example, from manufacturing. For example, a
region illustrated or described as flat may, typically, have rough
and/or nonlinear features. Moreover, sharp angles that are
illustrated may be rounded. Thus, the regions illustrated in the
figures are schematic in nature and their shapes are not intended
to illustrate the precise shape of a region and are not intended to
limit the scope of the present claims.
[0050] Hereinafter, an exemplary embodiment of an optical film
according to the invention will be described referring to FIG.
1.
[0051] FIG. 1 is a schematic cross-sectional view of an exemplary
embodiment of an optical film according to the invention, FIG. 2 is
a schematic view showing the external light anti-reflection
principle of an exemplary embodiment of an optical film according
to the invention, and FIG. 3 is a schematic view of an exemplary
embodiment of a polarization film according to the invention.
[0052] Referring to FIG. 1, an exemplary embodiment of an optical
film 100 according to the invention includes a polarization film
110 and a phase delay layer 120 disposed on the polarization film
110. In one exemplary embodiment, for example, the phase delay
layer 120 may be disposed or stacked on a surface of the
polarization film 110. The phase delay layer 120 may be, for
example, a .lamda./4 plate, and the phase delay layer 120 may
circularly polarize light passing through the polarization film 110
and thus cause retardation and have an influence on absorption and
reflection of the light.
[0053] Such an embodiment of the optical film 100 may be disposed
on a surface or both surfaces of a display device. In one exemplary
embodiment, for example, the optical film 100 may be disposed on a
screen side of the display device, and thus may effectively prevent
reflection of light flowing in from the outside (hereinafter
referred to as "reflection of external light"). Therefore, the
optical film 100 may effectively prevent visibility deterioration
due to the reflection of external light.
[0054] FIG. 2 is a schematic view showing the external light
anti-reflection principle of an exemplary embodiment of an optical
film according to the invention.
[0055] Referring to FIG. 2, when incident unpolarized light from
the outside is passed through the polarization film 110, and the
polarized light is shifted into circularly polarized light by
passing through the phase delay layer 120, only a first polarized
component (e.g., a horizontal component), which is one of two
polarized components perpendicular to each other, is transmitted.
When the circularly polarized light is reflected in a display panel
50 including a substrate, an electrode and so on, the circularly
polarized light changes the circular polarization direction, and
the circularly polarized light passes through the phase delay layer
120 again, such that only a second polarized component (e.g., a
perpendicular component), which is the other of the two polarized
components, may be transmitted. As the second polarized
perpendicular component is not passed through the polarization film
110, and light does not exit to the outside, thereby effectively
preventing the external light reflection.
[0056] Referring to FIG. 3, the polarization film 110 has a
self-integrated structure including a polymer resin 71 and a
dichroic dye 72, e.g., made of a melt blend of the polymer resin 71
and the dichroic dye 72.
[0057] In an exemplary embodiment, the polymer resin 71 may
include, for example, a hydrophobic polymer resin, for example a
polyolefin resin such as polyethylene ("PE"), polypropylene ("PP"),
and a copolymer thereof; a polyamide resin such as nylon and an
aromatic polyamide; a polyester resin such as polyethylene
terephthalate ("PET"), polyethylene terephthalate glycol ("PETG"),
and polyethylene naphthalate ("PEN"); a polyacrylic resin such as
polymethyl(meth)acrylate; a polystyrene resin such as polystyrene
("PS") and an acrylonitrile-styrene copolymer; a polycarbonate
resin; a vinyl chloride-based resin; a polyimide resin; a sulfone
resin; a polyethersulfone resin; a polyether-etherketone resin; a
polyphenylene sulfide resin; a vinyl alcohol resin; a vinylidene
chloride resin; a vinyl butyral resin; an allylate resin; a
polyoxymethylene resin; an epoxy resin; a copolymer thereof; or a
combination thereof.
[0058] In one exemplary embodiment, the polymer resin 71 may
include, for example, a polyolefin resin, a polyamide resin, a
polyester resin, a polyacrylic resin, a polystyrene resin, a
copolymer thereof, or a combination thereof, and for another
example, PE, PP, PET, PETG, PEN, nylon, a copolymer thereof, or a
combination thereof.
[0059] In one exemplary embodiment, the polymer resin 71 may
include, for example, at least two of PE, PP, and a copolymer of
polyethylene and polypropylene ("PE-PP"). In an alternative
exemplary embodiment, the polymer resin 71 may include a mixture of
PP and a PE-PP.
[0060] The PP may have, for example, a melt flow index ("MFI") in a
range from about 0.1 gram per 10 minutes (g/10 min) to about 5 g/10
min. Herein, the MFI is defined as the amount of a polymer in a
melt state flowing per 10 minutes, and relates to viscosity of the
polymer in a melted state. Accordingly, as the MFI is lower, the
polymer has higher viscosity, while as the MFI is higher, the
polymer has lower viscosity. When the PP has a MFI within the
range, properties of a final product and workability may be
effectively improved. In one exemplary embodiment, for example, the
polypropylene may have a MFI in a range from about 0.5 g/10 min to
about 5 g/10 min.
[0061] In an exemplary embodiment, the PE-PP may include an
ethylene group in an amount in a range from about 1 weight percent
(wt %) to about 50 wt % based on the total amount of the copolymer.
When the PE-PP includes the ethylene group in an amount within the
range, phase separation of the polypropylene and the PE-PP may be
effectively prevented or suppressed. In such an embodiment, the
PE-PP may improve an elongation rate during elongation as well as
have high light transmittance and alignment, thereby improving
polarization characteristics. In one exemplary embodiment, for
example, the PE-PP may include an ethylene group in an amount in a
range from about 1 wt % to about 25 wt % based on the total amount
of the copolymer.
[0062] The PE-PP may have a MFI in a range from about 5 g/10 min to
about 15 g/10 min. When the PE-PP has a MFI within the range,
properties of a final product as well as workability may be
effectively improved. In one exemplary embodiment, for example, the
PE-PP may have a MFI in a range from about 10 g/10 min to about 15
g/10 min.
[0063] The polymer resin 71 may include the PP and the PE-PP in a
weight ratio in a range from about 1:9 to about 9:1. When the PP
and the PE-PP of the polymer resin 71 is in the ratio, the PP may
be effectively prevented from crystallizing and may have high
mechanical strength, thus effectively improving the haze
characteristics. In one exemplary embodiment, for example, the
polymer resin 71 may include the PP and the PE-PP in a weight ratio
in a range from about 4:6 to about 6:4, or in a range from about
5:5.
[0064] The polymer resin 71 may have a MFI in a range from about 1
g/10 min to about 15 g/10 min. When the polymer resin 71 has a MFI
within the range, the polymer resin may not only secure excellent
light transmittance since crystals are not excessively formed in
the resin, but may also have appropriate viscosity for
manufacturing a film, thereby improving workability. In one
exemplary embodiment, for example, the polymer resin 71 may have a
MFI in a range from about 5 g/10 min to about 15 g/10 min.
[0065] The polymer resin 71 may have haze less than or equal to
about 5%. When the polymer resin 71 has haze within the range,
transmittance may be increased, and thus high optical properties
may be secured. In one exemplary embodiment, for example, the
polymer resin 71 may have haze less than or equal to about 2%, or
in a range about 0.5% to about 2%.
[0066] The polymer resin 71 may have crystallinity less than or
equal to about 50%. When the polymer resin 71 has crystallinity
within the range, the polymer resin may have lower haze and
accomplish excellent optical properties. In one exemplary
embodiment, for example, the polymer resin 71 may have
crystallinity in a range from about 30% to about 50%.
[0067] The polymer resin 71 may have transmittance greater than or
equal to about 85% in a wavelength region of about 400 nanometers
(nm) to about 780 nm. The polymer resin 71 may be elongated in a
uniaxial direction. The direction may be the length direction of
the dichroic dye 72.
[0068] In an exemplary embodiment, the dichroic dye 72 is dispersed
into the polymer resin 71 and aligned in the elongation direction
of the polymer resin 71. The dichroic dye 72 transmits a
polarization component of two polarization components perpendicular
to each other in a predetermined wavelength region.
[0069] The dichroic dye 72 may be included in an amount in a range
from about 0.01 parts by weight to about 5 parts by weight, based
on 100 parts by weight of the polymer resin 71. When the dichroic
dye 72 is within the range, sufficient polarization characteristics
may be obtained without deteriorating transmittance of a
polarization film. In one exemplary embodiment, for example, the
dichroic dye 72 may be included in an amount of about 0.05 part by
weight to about 1 part by weight, based on 100 parts by weight of
the polymer resin 71.
[0070] The polarization film 110 may have a dichroic ratio in a
range from about 2 to about 14 at a maximum absorption wavelength
(.lamda..sub.max) in a visible ray region. In one exemplary
embodiment, for example, the dichroic ratio may be in a range from
about 3 to about 10. Herein, the dichroic ratio is a value obtained
by dividing linear polarization absorption in a direction
perpendicular to the axis of the polymer by polarization absorption
in a direction parallel to the polymer, and the dichroic ratio of a
polarization film may be obtained by the following Equation 1.
DR=Log(1/T.sub..perp.)/Log(1/T.sub..parallel.) Equation 1:
[0071] In the Equation 1, DR denotes the dichroic ratio of the
polarization film, T.sub..parallel. denotes light transmittance of
light entering parallel to the transmissive axis of the
polarization film, and T.sub..perp. denotes light transmittance of
light entering perpendicular to the transmissive axis of the
polarization film.
[0072] The dichroic ratio refers to a degree that the dichroic dye
72 is aligned in one direction in the polarization film 110. The
polarization film 110 has a dichroic ratio within the range in a
visible ray wavelength region, by allowing the dichroic dye 72 to
be aligned along the alignment of a polymer chain, and thus the
polarizing characteristic thereof may be improved.
[0073] The polarization film 110 may have polarizing efficiency
greater than or equal to about 80%, e.g., in a range from about 83%
to about 99.9%. Herein, the polarizing efficiency of a polarization
film may be obtained by the following Equation 2.
PE
(%)=[(T.sub..parallel.-T.sub..perp.)/(T.sub..parallel.+T.sub..perp.)]-
.sup.1/2.quadrature.100 Equation 2:
[0074] In the Equation 2, PE denotes the polarizing efficiency,
T.sub..parallel. denotes light transmittance of the polarization
film regarding light parallel to the transmissive axis of the
polarization film, and T.sub..perp. denotes light transmittance of
the polarization film regarding light perpendicular to the
transmissive axis of the polarization film.
[0075] The polarizing film 110 may have a relatively thin thickness
less than or equal to about 100 micrometers (.mu.m), for example,
in a range from about 30 .mu.m to about 95 .mu.m. When the
polarizing film 70 has a thickness with the range, the polarizing
film 70 may be thinner than a polarizing plate including a
protective layer such as triacetyl cellulose ("TAC"), such that a
display device including the polarizing film 70 may have a reduced
thickness.
[0076] The phase delay layer 120 may be disposed on the
polarization film 110, and may include an anisotropic liquid
crystal layer including liquid crystal.
[0077] The liquid crystal may have a rigid-rod shape that is
aligned in a same direction or a flat-disc shape, and may be, for
example a monomer, an oligomer, or a polymer. The liquid crystal
may have, for example, positive or negative birefringence. The
birefringence (.DELTA.n) is a difference acquired by subtracting
the refractive index (n.sub.o) of light propagating perpendicular
to an optical axis from the refractive index (n.sub.e) of light
propagating parallel to the optical axis. The liquid crystal may be
aligned in a predetermined direction along the optical axis.
[0078] The liquid crystal may be a reactive mesogen liquid crystal,
and may have, for example, a reactive cross-linking group. The
reactive mesogen liquid crystal may include, for example, a
rod-shaped aromatic derivative having at least one reactive
cross-linking group, propylene glycol 1-methyl, propylene glycol
2-acetate, a compound represented by P1-A1-(Z1-A2)n-P2, or a
combination thereof, where P1 and P2 independently include
acrylate, methacrylate, vinyl, vinyloxy, epoxy or a combination
thereof, A1 and A2 independently include a 1,4-phenylene,
naphthalene-2,6-diyl group or a combination thereof, Z1 includes a
single bond, --COO--, --OCO-- or a combination thereof, and n is 0,
1 or 2, but is not limited thereto.
[0079] The phase delay layer 120 may have inverse wavelength
dispersion phase delay. Herein, the inverse wavelength dispersion
phase delay means that retardation of light having a long
wavelength is higher than retardation of light having a short
wavelength.
[0080] The phase delay may be represented by in-plane phase
retardation (R.sub.e0), and in-plane phase retardation (R.sub.e0)
may be represented by the following equation:
R.sub.e0=(n.sub.x0-n.sub.y0).times.d.sub.0. Herein, n.sub.x0
denotes a refractive index in a direction having a highest
refractive index in a plane of the phase delay layer 120
(hereinafter referred to as "slow axis"), n.sub.y0 denotes a
refractive index in a direction having a lowest refractive index in
a plane of the phase delay layer 120 (hereinafter referred to as
"fast axis"), and d.sub.0 denotes a thickness of the phase delay
layer 120.
[0081] The in-plane phase retardation may be provided within a
predetermined range by changing thicknesses or refractive indices
at the slow or fast axis of the phase delay layer 120.
[0082] According to one exemplary embodiment, the in-plane phase
retardation (R.sub.e0) of the phase delay layer 120 for 550 nm
wavelength (hereinafter referred to as "reference wavelength") may
be in a range from about 120 nm to about 160 nm.
[0083] In the phase delay layer 120, the retardation of light
having a long wavelength is higher than the retardation of light
having a short wavelength as described above. In one exemplary
embodiment, for example, the in-plane phase retardation (R.sub.e0)
of the phase delay layer 120 for 450 nm, 550 nm, and 650 nm
wavelengths may satisfy the following inequality: R.sub.e0 (450
nm).ltoreq.R.sub.e0 (550 nm)<R.sub.e0 (650 nm) or R.sub.e0 (450
nm)<R.sub.e0 (550 nm).ltoreq.R.sub.e0 (650 nm). Herein, R.sub.e0
(450 nm) denotes the in-plane phase retardation for 450 nm
wavelength, R.sub.e0 (550 nm) denotes in-plane phase retardation
for 550 nm wavelength, and R.sub.e0 (650 nm) denotes in-plane phase
retardation for 650 nm wavelength.
[0084] The changing of the retardation of the short wavelength for
the reference wavelength may be represented by short wavelength
dispersion, that is, R.sub.e0 (450 nm)/R.sub.e0 (550 nm). In one
exemplary embodiment, for example, the short wavelength dispersion
of the phase delay layer 120 may be in a range from about 0.70 to
about 0.99.
[0085] The changing of the retardation of the long wavelength for
the reference wavelength may be represented by long wavelength
dispersion, that is, R.sub.e0 (650 nm)/R.sub.e0 (550 nm). In one
exemplary embodiment, for example, the long wavelength dispersion
of the phase delay layer 120 may be in a range from about 1.01 to
about 1.20.
[0086] On the other hand, the retardation includes thickness
direction retardation (R.sub.th) besides the in-plane retardation
(R.sub.e0). The thickness direction retardation (R.sub.th0) is
retardation generated in a thickness direction of the phase delay
layer 120, and the thickness direction retardation (R.sub.th0) of
the phase delay layer 120 may be represented by the following
equation:
R.sub.th0={[(n.sub.x0+n.sub.y0)/2]-n.sub.z0}.times.d.sub.0. Herein,
n.sub.x0 denotes a refractive index at a slow axis of the phase
delay layer 120, n.sub.y0 denotes a refractive index at a fast axis
of the phase delay layer 120, and n.sub.z0 denotes a refractive
index of the phase delay layer 120 in a direction perpendicular to
the fast and slow axes thereof.
[0087] In one exemplary embodiment, for example, thickness
direction retardation (R.sub.th0) of the phase delay layer 120 for
a reference wavelength may be in a range from about -250 nm to
about 250 nm.
[0088] The phase delay layer 120 may have a thickness less than or
equal to about 10 .mu.m.
[0089] The phase delay layer 120 may be disposed on the
polarization film 110, and the phase delay layer 120 and the
polarization film 110 may contact each other directly or an
adhesion layer (not shown) may be interposed therebetween. Herein,
the adhesion layer may include, for example, a pressure sensitive
adhesive.
[0090] In one exemplary embodiment, for example, the optical film
100 may be prepared by melt-blending a polymer resin and a dichroic
dye to prepare a polarization film 110, preparing a phase delay
layer 120 including liquid crystal on a substrate, and forming the
phase delay layer 120 on a surface of the polarization film
110.
[0091] In an exemplary embodiment, the polarization film 110 is
prepared by melt-blending a composition including the polymer resin
71 and the dichroic dye 72, putting the melt-blend into a mold and
pressing it into a sheet, and elongating the sheet in a uniaxial
direction.
[0092] In an exemplary embodiment, the polymer resin 71 and the
dichroic dye 72 may be independently in a solid form such as a
powder, and may be melt-blended at a temperature above the melting
point (T.sub.m) of the polymer resin 71 and elongated to prepare
the polarization film 110.
[0093] The melt-blending may be performed at a temperature less
than or equal to about 300.degree. C., or in a range from about
130.degree. C. to about 300.degree. C. The sheet may be formed by
putting the melt blend in the mold, and pressing the melt blend
with a high pressure or discharging the melt blend in a chill roll
through a T-die. The elongation in a uniaxial direction may be
performed at a temperature in a range from about 25.degree. C. to
about 200.degree. C. at an elongation rate in a range from about
400% to about 1000%. The elongation rate refers to a length ratio
of after the elongation to before the elongation of the sheet, and
represents the elongation extent of the sheet after uniaxial
elongation.
[0094] The phase delay layer 120 may be prepared by coating a
liquid crystal solution on a substrate and curing the coated liquid
crystal solution with photo-radiation. The substrate may be, for
example, a TAC film, but is not limited thereto. The phase delay
layer 120 may be prepared by removing the phase delay layer 120
from the substrate and transferring the phase delay layer 120 on a
surface of the polarization film 110. Herein, an adhesion layer may
be provided, e.g., formed, on a surface of the polarization film
110 or on a surface of the phase delay layer 120. However, the
transferring method is not limited to the above method, and may be,
for example, roll-to-roll, spin coating, and the like.
[0095] The optical film 100 may further include a correction layer
(not shown) disposed on the phase delay layer 120. The correction
layer may be, for example, a color shift resistant layer, but is
not limited thereto.
[0096] The optical film 100 may further include a light blocking
layer (not shown) extending along an edge thereof. The light
blocking layer may have a strip shape extending along a
circumference of the optical film 100, and for example, may be
disposed between the polarization film 110 and the phase delay
layer 120. The light blocking layer may include an opaque material,
for example, a black material. In one exemplary embodiment, for
example, the light blocking layer may include or be made of a black
ink.
[0097] Hereinafter, an alternative exemplary embodiment of an
optical film according to the invention will be described.
[0098] FIG. 4 is a schematic view of an alternative exemplary
embodiment of an optical film according to the invention.
[0099] Referring to FIG. 4, the optical film 100 includes a
polarization film 110 and a phase delay layer 120 disposed on the
polarization film 110.
[0100] In an exemplary embodiment, as shown in FIG. 4, the phase
delay layer 120 may include a plurality of phase delay layers,
e.g., a first phase delay layer 120a and a second phase delay layer
120b having different retardation from each other.
[0101] In such an embodiment, one of the first phase delay layer
120a and the second phase delay layer 120b may be a .lamda./2 phase
delay layer 120, and the other may be a .lamda./4 phase delay layer
120. In one exemplary embodiment, for example, the first phase
delay layer 120a may be a .lamda./2 phase delay layer 120 and the
second phase delay layer 120b may be a .lamda./4 phase delay layer
120.
[0102] The first phase delay layer 120a and the second phase delay
layer 120b may each be an anisotropic liquid crystal layer
including liquid crystal, and the first phase delay layer 120a and
the second phase delay layer 120b may independently have positive
or negative birefringence.
[0103] The first phase delay layer 120a and second phase delay
layer 120b may each have forward wavelength dispersion phase delay,
and a combination of the first phase delay layer 120a and the
second phase delay layer 120b may have an inverse wavelength
dispersion phase delay. The forward wavelength dispersion phase
delay has higher retardation of light having a short wavelength
than retardation of light having a long wavelength, and the reverse
wavelength dispersion phase delay has higher retardation of light
having a long wavelength than retardation of light having a short
wavelength.
[0104] The phase delay may be represented by in-plane phase
retardation, in-plane phase retardation (R.sub.e1) of the first
phase delay layer 120a may be represented by the following
equation: R.sub.e1=(n.sub.x1-n.sub.y1).times.d.sub.1, in-plane
phase retardation (R.sub.e2) of the second phase delay layer 120b
may be represented by the following equation:
R.sub.e2=(n.sub.x2-n.sub.y2).times.d.sub.2, and the entire in-plane
phase retardation (R.sub.e0) of the phase delay layer 120 may be
represented by the following equation:
R.sub.e0=(n.sub.x0-n.sub.y0).times.d.sub.0. Herein, n.sub.x1
denotes a refractive index at a slow axis of the first phase delay
layer 120a, n.sub.x1 denotes a refractive index at a fast axis of
the first phase delay layer 120a, d.sub.1 denotes a thickness of
the first phase delay layer 120a, n.sub.x2 denotes a refractive
index at a slow axis of the second phase delay layer 120b, n.sub.y2
denotes a refractive index at a fast axis of the second phase delay
layer 120b, d.sub.2 denotes a thickness of the second phase delay
layer 120b, n.sub.x0 denotes a refractive index at a slow axis of
the phase delay layer 120, n.sub.y0 denotes a refractive index at a
fast axis of the phase delay layer 120, and do denotes a thickness
of the phase delay layer 120.
[0105] Accordingly, the in-plane retardation (R.sub.e1 and
R.sub.e2) may be provided within a predetermined range by changing
refractive indices at the slow or fast axis or thicknesses of the
first phase delay layer 120a and the second phase delay layer
120b.
[0106] According to one exemplary embodiment, in-plane phase
retardation (R.sub.e1) for a reference wavelength of the first
phase delay layer 120a may be in a range from about 230 nm to about
270 nm, in-plane phase retardation (R.sub.e2) for a reference
wavelength of the second phase delay layer 120b may be in a range
from about 100 nm to about 140 nm, entire in-plane phase
retardation of the first phase delay layer 120a and the second
phase delay layer 120b, that is, in-plane phase retardation
(R.sub.e0) of the phase delay layer 120, for incident light having
a reference wavelength, may be the difference between the in-plane
retardation (R.sub.e1) of the first phase delay layer 120a and the
in-plane retardation (R.sub.e2) of the second phase delay layer
120b. In one exemplary embodiment, for example, the in-plane phase
retardation (R.sub.e0) of the phase delay layer 120 for a reference
wavelength may be in a range from about 120 nm to about 160 nm.
[0107] In the first phase delay layer 120a and the second phase
delay layer 120b, the retardation of light having a short
wavelength may be higher than the retardation of light having a
long wavelength as described above. In one exemplary embodiment,
for example, the in-plane retardation (R.sub.e1) of the first phase
delay layer 120a for the wavelengths of 450 nm, 550 nm and 650 nm
may satisfy the following inequality: R.sub.e1 (450
nm).gtoreq.R.sub.e1 (550 nm)>R.sub.e1 (650 nm) or R.sub.e1 (450
nm)>R.sub.e1 (550 nm).gtoreq.R.sub.e1 (650 nm), and the in-plane
retardation (R.sub.e2) of the second phase delay layer 120b for the
wavelengths of 450 nm, 550 nm and 650 nm may satisfy the following
inequality: R.sub.e2 (450 nm)>R.sub.e2 (550 nm)>R.sub.e2 (650
nm).
[0108] The combination of the first phase delay layer 120a and the
second phase delay layer 120b may have higher retardation of light
having a long wavelength than the retardation of light having a
short wavelength as described above. In one exemplary embodiment,
for example, the in-plane phase retardation (R.sub.e0) of the first
phase delay layer 120a and the second phase delay layer 120b at 450
nm, 550 nm and 650 nm wavelengths may satisfy the following
inequality: R.sub.e0 (450 nm).ltoreq.R.sub.e0 (550 nm)<R.sub.e0
(650 nm) or R.sub.e0 (450 nm)<R.sub.e0 (550 nm).ltoreq.R.sub.e0
(650 nm).
[0109] The changing of the retardation of the short wavelength for
the reference wavelength may be represented by short wavelength
dispersion, the short wavelength dispersion of the first phase
delay layer 120a may be represented by R.sub.e1 (450 nm)/R.sub.e1
(550 nm), and the short wavelength dispersion of the second phase
delay layer 120b may be represented by R.sub.e2 (450 nm)/R.sub.e2
(550 nm). In one exemplary embodiment, for example, the short
wavelength dispersion of the first phase delay layer 120a and the
second phase delay layer 120b may independently be in a range from
about 1.1 to about 1.2, and the entire short wavelength dispersion
of the first phase delay layer 120a and the second phase delay
layer 120b may be in a range from about 0.70 to about 0.99.
[0110] The changing of the retardation of the long wavelength for
the reference wavelength may be represented by long wavelength
dispersion, the long wavelength dispersion of the first phase delay
layer 120a may be represented by R.sub.e1 (650 nm)/R.sub.e1 (550
nm), and the long wavelength dispersion of the second phase delay
layer 120b may be represented by R.sub.e2 (650 nm)/R.sub.e2 (550
nm). In one exemplary embodiment, for example, the long wavelength
dispersion of the first phase delay layer 120a and the second phase
delay layer 120b may independently be in a range from about 0.9 to
about 1.0, and the entire long wavelength dispersion of the first
phase delay layer 120a and the second phase delay layer 120b may be
in a range from about 1.01 to about 1.20.
[0111] On the other hand, the thickness direction retardation
(R.sub.th1) of the first phase delay layer 120a may be represented
by the following equation:
R.sub.th1={[(n.sub.x1+n.sub.y1)/2]-n.sub.z1}.times.d.sub.1, the
thickness direction retardation (R.sub.th2) of the second phase
delay layer 120b may be represented by the following equation:
R.sub.th2={[(n.sub.x2+n.sub.y2)/2]+n.sub.z2}.times.d.sub.2, and the
thickness direction retardation (R.sub.th0) of the combined first
phase delay layer 120a and the second phase delay layer 120b may be
represented by the following equation:
R.sub.th0={[(n.sub.x0+n.sub.y0)/2]-n.sub.z0}.times.d.sub.0. Herein,
n.sub.x1 denotes a refractive index at a slow axis of the first
phase delay layer 120a, n.sub.y1 denotes a refractive index at a
fast axis of the first phase delay layer 120a, n.sub.z1 denotes a
refractive index of the first phase delay layer 120a in a direction
perpendicular to the slow and fast axes thereof, n.sub.x2 denotes a
refractive index at a slow axis of the second phase delay layer
120b, n.sub.y2 denotes a refractive index at a fast axis of the
second phase delay layer 120b, n.sub.z2 denotes a refractive index
of the second phase delay layer 120b in a direction perpendicular
to the fast and slow axes thereof, n.sub.x0 denotes a refractive
index at a slow axis of the phase delay layer 120, n.sub.y0 denotes
a refractive index at a fast axis of the phase delay layer 120, and
n.sub.z0 denotes a refractive index of the phase delay layer 120 in
a direction perpendicular to the fast and slow axes thereof.
[0112] The thickness direction retardation (R.sub.th0) of the phase
delay layer 120 may be the sum of the thickness direction
retardation (R.sub.th1) of the first phase delay layer 120a and the
thickness direction retardation (R.sub.th2) of the second phase
delay layer 120b.
[0113] An angle between a slow axis of the first phase delay layer
120a and a slow axis of the second phase delay layer 120b may be in
a range from about 50 to about 70 degrees. In one exemplary
embodiment, for example, the angle may be, for example, in a range
from about 55 to about 65 degrees, in a range from about 52.5 to
about 62.5 degrees, or in a range from about 60 degrees. In one
exemplary embodiment, for example, the slow axis of the first phase
delay layer 120a may be about 15 degrees, the slow axis of the
second phase delay layer 120b may be about 75 degrees, and an angle
therebetween may be about 60 degrees.
[0114] In an exemplary embodiment, the first phase delay layer 120a
and the second phase delay layer 120b may independently have
respective refractive indices satisfying the following relationship
1A or 1B.
n.sub.x>n.sub.y=n.sub.z Relationship Equation 1A:
n.sub.x<n.sub.y=n.sub.z Relationship Equation 1B:
[0115] In the Relationship Equation 1A and 1B, n.sub.x denotes a
refractive index of the first or second phase delay layer at a slow
axis thereof, n.sub.y denotes a refractive index of the first or
second phase delay layer at a fast axis thereof, and n.sub.z
denotes a refractive index of the first or second phase delay layer
in a direction perpendicular to the fast and slow axes thereof.
[0116] As an example, the first phase delay layer 120a and the
second phase delay layer 120b may have refractive indices
satisfying the relationship 1A, respectively.
[0117] As an example, the first phase delay layer 120a and the
second phase delay layer 120b may have refractive indices
satisfying the relationship 1B, respectively.
[0118] As an example, the first phase delay layer 120a may have
refractive indices satisfying the relationship 1A and the second
phase delay layer 120b may have refractive indices satisfying the
relationship 1B.
[0119] As an example, the first phase delay layer 120a may have
refractive indices satisfying the relationship 1B and the second
phase delay layer 120b may have refractive indices satisfying the
relationship 1A.
[0120] The first phase delay layer 120a and the second phase delay
layer 120b may independently be less than or equal to about 5
.mu.m.
[0121] In an exemplary embodiment, the first phase delay layer 120a
and the second phase delay layer 120b may contact directly each
other. In an alternative exemplary embodiment, an adhesion layer
(not shown) may be disposed therebetween. In such an embodiment,
the adhesion layer may include, for example, a pressure sensitive
adhesive.
[0122] In an exemplary embodiment, the first phase delay layer 120a
and the second phase delay layer 120b may be formed by applying a
liquid crystal solution on a substrate. In such an embodiment, the
first phase delay layer 120a and the second phase delay layer 120b
may be formed on respective substrates or be sequentially formed on
a same substrate. The substrate may be, for example, a TAC film,
but is not limited thereto. The solution may include a liquid
crystal and a solvent such as toluene, xylene, cyclohexanone, and
the like, and the solution may be, for example, applied on the
transparent substrate with a solution process such as spin coating.
Subsequently, the solution may be further dried, and for example,
cured with ultraviolet ("UV") rays.
[0123] The phase delay layer 120 may accomplish the reverse
wavelength dispersion delay by assembling the first phase delay
layer 120a and the second phase delay layer 120b having
predetermined optical properties, and may provide .lamda./4
retardation in the entire visible ray region. Accordingly, the
phase delay layer 120 may effectively accomplish the circularly
polarized compensation function, and the display characteristics of
the display device including an optical film including the
polarization film 110 may be improved.
[0124] Such an embodiment of the optical film 100 may be applied to
various display devices.
[0125] In an exemplary embodiment, a display device includes a
display panel and an optical film positioned on a surface of the
display panel. The display panel may be a liquid crystal panel or
organic light emitting diode panel, but is not limited thereto.
[0126] Hereinafter, an exemplary embodiment of a display device,
where the display device is an organic light emitting display, will
be described in detail.
[0127] FIG. 5 is a cross-sectional view showing an exemplary
embodiment of an organic light emitting display according to the
invention.
[0128] Referring to FIG. 5, an exemplary embodiment of the organic
light emitting display according to the invention includes an
organic light emitting diode panel 400 and an optical film 100
disposed on a surface (e.g., an upper surface or a front surface)
of the organic light emitting diode panel 400.
[0129] The organic light emitting diode panel 400 may include a
base substrate 410, a lower electrode 420, an organic emission
layer 430, an upper electrode 440, and an encapsulation substrate
450.
[0130] The base substrate 410 may include or be made of glass or
plastic.
[0131] At least one of the lower electrode 420 and the upper
electrode 440 may be an anode, and the other one may be a cathode.
The anode is an electrode injected with holes, and may include or
be made of a transparent conductive material having a high work
function to transmit the emitted light to the outside, for example,
indium tin oxide ("ITO") or indium zinc oxide ("IZO"). The cathode
is an electrode injected with electrons, and may include be made of
a conductive material having a low work function and not affecting
the organic material, for example, aluminum (Al), calcium (Ca),
barium (Ba) or a combination thereof.
[0132] The organic emission layer 430 includes an organic material
which may emit light when a voltage is applied to the lower
electrode 420 and the upper electrode 440.
[0133] In such an embodiment, an auxiliary layer (not shown) may be
further provided between the lower electrode 420 and the organic
emission layer 430 and between the upper electrode 440 and the
organic emission layer 430. The auxiliary layer balances electrons
and holes, and may include a hole transport layer, a hole injection
layer ("HIL"), an electron injection layer ("EIL"), and an electron
transporting layer.
[0134] The encapsulation substrate 450 may include or be made of
glass, metal or a polymer, and may seal the lower electrode 420,
the organic emission layer 430 and the upper electrode 440, to
effectively prevent moisture and/or oxygen inflow from the
outside.
[0135] The optical film 100 may be disposed on a light-emitting
side of the organic light emitting diode panel 400. In an exemplary
embodiment of the organic light emitting display having a bottom
emission structure, in which light is emitted at a side of the base
substrate 410, the optical film 100 may be disposed on an exterior
side of the base substrate 410. In an exemplary embodiment of the
organic light emitting display having a top emission structure, in
which light is emitted at a side of the encapsulation substrate
450, the optical film 100 may be disposed on an exterior side of
the encapsulation substrate 450.
[0136] The optical film 100 includes the polarization film 110 and
the phase delay layer 120. In such an embodiment, as described
above, the polarization film 110 may be self-integrated and formed
of a melt blend of a polymer resin and a dichroic dye, and the
phase delay layer 120 may be a single-layered or multi-layered
(e.g., two-layered) liquid crystal anisotropic layer, as described
above. The polarization film 110 and the phase delay layer 120 are
substantially the same as those described above, and may
effectively prevent a display device from having visibility
deterioration caused by light inflowing from the outside after
passing the polarization film 110 and being reflected by a metal,
such as an electrode and the like, in the organic light emitting
diode panel 400. Accordingly, display characteristics of the
organic light emitting display including such an optical film may
be substantially improved.
[0137] Hereinafter, a liquid crystal display ("LCD") is described
as one example of the display device.
[0138] FIG. 6 is a cross-sectional view schematically showing an
exemplary embodiment of an LCD according to the invention.
[0139] Referring to FIG. 6, an exemplary embodiment of the LCD
according to the invention includes a liquid crystal panel 500, and
an optical film 100 disposed on the liquid crystal panel 500. In
one exemplary embodiment, for example, the optical film 100 may be
disposed on an upper or lower surface of the liquid crystal panel
500.
[0140] The liquid crystal panel 500 may be a twist nematic ("TN")
mode panel, a vertical alignment ("PVA") mode panel, an in-plane
switching ("IPS") mode panel or an optically compensated bend
("OCB") mode panel, for example.
[0141] In an exemplary embodiment, as shown in FIG. 6, the liquid
crystal panel 500 may include a first display panel 510, a second
display panel 520, and a liquid crystal layer 530 interposed
between the first display panel 510 and the second display panel
520.
[0142] In an exemplary embodiment, the first display panel 510 may
include, for example, a thin film transistor (not shown) disposed
on a substrate (not shown) and a first electric field generating
electrode (not shown) connected to the thin film transistor, and
the second display panel 520 may include, for example, a color
filter (not shown) disposed on a substrate (not shown) and a second
electric field generating electrode (not shown), but not being
limited thereto. In an alternative exemplary embodiment, the color
filter may be included in the first display panel 510, and the
first electric field generating electrode and the second electric
field generating electrode may be disposed on the first display
panel 510.
[0143] The liquid crystal layer 530 may include a plurality of
liquid crystal molecules. The liquid crystal molecules may have
positive or negative dielectric anisotropy. In an exemplary
embodiment, where the liquid crystal molecules having positive
dielectric anisotropy, the major (e.g., longitudinal) axes thereof
may be aligned substantially parallel to the surface of the first
display panel 510 and the second display panel 520 when an electric
field is not applied thereto, and the major axes may be aligned
substantially perpendicular to the surface of the first display
panel 510 and second display panel 520 when an electric field is
applied thereto. In an exemplary embodiment, where the liquid
crystal molecules having negative dielectric anisotropy, the major
axes may be aligned substantially perpendicular to the surface of
the first display panel 510 and the second display panel 520 when
an electric field is not applied thereto, and the major axes may be
aligned substantially parallel to the surface of the first display
panel 510 and the second display panel 520 when an electric field
is applied thereto.
[0144] In an exemplary embodiment, the optical film 100 may be
disposed on the outside (e.g., an external surface) of the liquid
crystal panel 500. In an exemplary embodiment, as shown in FIG. 6,
the optical film 100 may be disposed on both opposing surfaces
(e.g., lower and upper surfaces) of the liquid crystal panel 500,
but not being limited thereto. In an alternative exemplary
embodiment, the optical film 100 may be disposed on only one of the
lower and upper surfaces of the liquid crystal panel 500.
[0145] The optical film 100 include the polarization film 110,
which may be self-integrated and formed of a melt blend of a
polymer resin and a dichroic dye, and the phase delay layer 120,
which is a one- or two-layered liquid crystal anisotropic layer as
described above. In such an embodiment, the optical film 100 is
substantially the same as the optical film described above, and any
repetitive detailed description thereof will be omitted.
[0146] Hereinafter, the disclosure will be described in greater
detail with reference to examples. However, these examples are
described for exemplary purposes only, and the invention is not
limited thereto or thereby.
Manufacture of Polarization Film or Polarizing Plate
Preparation Example 1
[0147] A composition for a polarization film is prepared by mixing
a polymer resin including PP and a PP-PE in a weight ratio of 5:5
(w/w), and each dichroic dye represented by the following Chemical
Formulae A, B and C in amounts of 0.5, 0.2 and 0.3 parts by weight,
respectively, based on 100 parts by weight of the polymer
resin.
##STR00001##
[0148] The composition for a polarization film is melt-mixed at
250.degree. C. using a Micro-compounder made by DSM. The melt blend
is put in a sheet-shaped mold and pressed with a high pressure at a
high temperature, thereby manufacturing a film. Subsequently, the
film is 1000% elongated in a uniaxial direction at 115.degree. C.
(using a tensile tester made by Instron), thereby manufacturing a
20 .mu.m-thick polarization film.
Comparative Preparation Example 1
[0149] A polyvinyl alcohol ("PVA") film (PS 60, Kuraray) is
elongated, thereby manufacturing a 30 .mu.m-thick PVA film.
Subsequently, a 40 .mu.m-thick TAC film (Fuji Film Corp.) is
respectively attached on both sides of the elongated PVA film,
thereby manufacturing a polarizing plate.
Preparation of Phase Delay Layer
Preparation Example 2
[0150] A 60 .mu.m-thick Z-TAC film (Fuji Film Corp.) is rubbed to
be aligned in one direction, coated with biaxial liquid crystals
(n.sub.x.noteq.n.sub.y.noteq.n.sub.z, RMS03-013C, Merck & Co.,
Inc.), and dried in a drying oven at 60.degree. C. for 1 minute to
remove a coating solvent. Subsequently, the coated liquid crystals
are photo-cross-linked by UV rays at 80 milliwatts per square
centimeter (mW/cm.sup.2) for 30 seconds in a container filled with
nitrogen, forming a .lamda./4 phase delay layer having optical
properties as in the following Table 1. Then, in-plane phase
retardation, thickness direction retardation, and wavelength
dispersion of the .lamda./4 phase delay layer are measured by using
Axoscan equipment (Axometrics Inc.).
TABLE-US-00001 TABLE 1 Thickness In-plane phase Wavelength
dispersion direction retardation (R.sub.e) R.sub.e (450 nm)/
R.sub.e (650 nm)/ retardation Thickness R.sub.e (550 nm) R.sub.e
(550 nm) R.sub.e (550 nm) (R.sub.th) (.mu.m) .lamda./4 143 0.91
1.01 106 4
Preparation Example 3
[0151] A 60 .mu.m-thick Z-TAC film (Fuji Film Corp.) is rubbed to
be aligned in one direction, coated with +A plate liquid crystals
(n.sub.x>n.sub.y=n.sub.z, RMM141C, Merck & Co., Inc.), and
dried in an oven at 60.degree. C. for 1 minute to remove a coating
solvent. Subsequently, the coated liquid crystals are
photo-cross-linked by radiating UV rays at 80 mW/cm.sup.2 for 30
seconds in a container filled with nitrogen, forming a .lamda./2
phase delay layer having optical properties as in the following
Table 2. Subsequently, a 60 .mu.m-thick Z-TAC film (Fuji Film
Corp.) is rubbed and orientation-treated in one direction, coated
with +A plate liquid crystals (n.sub.x>n.sub.y=n.sub.z, RMM141C,
Merck & Co., Inc.), and then dried in an oven at 60.degree. C.
for 1 minutes to remove a coating solvent. Subsequently, the coated
crystal are photo-cross-linked by radiating UV rays at 80
mW/cm.sup.2 for 30 seconds in a container filled with nitrogen,
forming a .lamda./4 phase delay layer having optical properties as
in the following Table 2.
TABLE-US-00002 TABLE 2 In-plane phase Thickness retardation
Wavelength dispersion direction (R.sub.e) R.sub.e (450 nm)/ R.sub.e
(650 nm)/ retardation Thickness R.sub.e (550 nm) R.sub.e (550 nm)
R.sub.e (550 nm) (R.sub.th) (.mu.m) .lamda./2 249 1.12 0.95 116 2
.lamda./4 122 1.12 0.95 56 1 .lamda./2 + 140 0.77 1.09 172 3
.lamda./4
Preparation Example 4
[0152] A 60 .mu.m-thick Z-TAC film (Fuji Film Corp.) is rubbed to
be aligned in one direction, coated with +A plate liquid crystals
(n.sub.x>n.sub.y=n.sub.z, RMM141C, Merck & Co., Inc.), and
dried in an oven at 60.degree. C. for 1 minute to remove a coating
solvent. Subsequently, the coated liquid crystals are
photo-cross-linked by radiating UV rays at 80 mW/cm.sup.2 for 30
seconds in a container filled with nitrogen, forming a .lamda./2
phase delay layer having optical properties as in the following
Table 3. Subsequently, a 60 .mu.m-thick Z-TAC film (Fuji Film
Corp.) is rubbed and orientation-treated in one direction, coated
with +A plate liquid crystals (n.sub.x>n.sub.y=n.sub.z, RMM141C,
Merck & Co., Inc.), and then dried in an oven at 60.degree. C.
for 1 minutes to remove a coating solvent. Subsequently, the coated
crystal are photo-cross-linked by radiating UV rays at 80
mW/cm.sup.2 for 30 seconds in a container filled with nitrogen,
forming a .lamda./4 phase delay layer having optical properties as
in the following Table 3.
TABLE-US-00003 TABLE 3 In-plane phase Thickness retardation
Wavelength dispersion direction (R.sub.e) R.sub.e (450 nm)/ R.sub.e
(650 nm)/ retardation Thickness R.sub.e (550 nm) R.sub.e (550 nm)
R.sub.e (550 nm) (R.sub.th) (.mu.m) .lamda./2 240 1.12 0.95 110 2
.lamda./4 120 1.12 0.97 57 1 .lamda./2 + 134 0.78 1.06 167 3
.lamda./4
Preparation Example 5
[0153] A 60 .mu.m-thick Z-TAC film (Fuji Film Corp.) is rubbed to
be aligned in one direction, coated with -A plate liquid crystals
(n.sub.x<n.sub.y=n.sub.z, discotic liquid crystal), and dried in
an oven at 60.degree. C. for 1 minute to remove a coating solvent.
Subsequently, the coated liquid crystals are photo-cross-linked by
radiating UV rays at 80 mW/cm.sup.2 for 30 seconds in a container
filled with nitrogen, forming a .lamda./2 phase delay layer having
optical properties as in the following Table 4. Subsequently, a 60
.mu.m-thick Z-TAC film (Fuji Film Corp.) is rubbed and
orientation-treated in one direction, coated with -A plate liquid
crystals (n.sub.x<n.sub.y=n.sub.z, discotic liquid crystal), and
then dried in an oven at 60.degree. C. for 1 minutes to remove a
coating solvent. Subsequently, the coated crystal are
photo-cross-linked by radiating UV rays at 80 mW/cm.sup.2 for 30
seconds in a container filled with nitrogen, forming a .lamda./4
phase delay layer having optical properties as in the following
Table 4.
TABLE-US-00004 TABLE 4 In-plane phase Thickness retardation
Wavelength dispersion direction (R.sub.e) R.sub.e (450 nm)/ R.sub.e
(650 nm)/ retardation Thickness R.sub.e (550 nm) R.sub.e (550 nm)
R.sub.e (550 nm) (R.sub.th) (.mu.m) .lamda./2 240 1.09 0.96 -105 2
.lamda./4 120 1.08 0.96 -56 1 .lamda./2 + 141 0.78 1.10 -161 3
.lamda./4
Preparation Example 6
[0154] A 60 .mu.m-thick Z-TAC film (Fuji Film Corp.) is rubbed to
be aligned in one direction, coated with -A plate liquid crystals
(n.sub.x<n.sub.y=n.sub.z, discotic liquid crystal), and dried in
an oven at 60.degree. C. for 1 minute to remove a coating solvent.
Subsequently, the coated liquid crystals are photo-cross-linked by
radiating UV rays at 80 mW/cm.sup.2 for 30 seconds in a container
filled with nitrogen, forming a .lamda./2 phase delay layer having
optical properties as in the following Table 5. Subsequently, a 60
.mu.m-thick Z-TAC film (Fuji Film Corp.) is rubbed and
orientation-treated in one direction, coated with +A plate liquid
crystals (n.sub.x>n.sub.y=n.sub.z, RMM141C, Merck & Co.,
Inc.), and then dried in an oven at 60.degree. C. for 1 minutes to
remove a coating solvent. Subsequently, the coated crystal are
photo-cross-linked by radiating UV rays at 80 mW/cm.sup.2 for 30
seconds in a container filled with nitrogen, forming a .lamda./4
phase delay layer having optical properties as in the following
Table 5.
TABLE-US-00005 TABLE 5 In-plane phase Thickness retardation
Wavelength dispersion direction (R.sub.e) R.sub.e (450 nm)/ R.sub.e
(650 nm)/ retardation Thickness R.sub.e (550 nm) R.sub.e (550 nm)
R.sub.e (550 nm) (R.sub.th) (.mu.m) .lamda./2 240 1.09 0.96 -105 2
.lamda./4 120 1.12 0.97 57 1 .lamda./2 + 138 0.84 1.08 -48 3
.lamda./4
Preparation Example 7
[0155] A 60 .mu.m-thick Z-TAC film (Fuji Film Corp.) is rubbed to
be aligned in one direction, coated with +A plate liquid crystals
(n.sub.x>n.sub.y=n.sub.z, RMM141C, Merck & Co., Inc.), and
dried in an oven at 60.degree. C. for 1 minute to remove a coating
solvent. Subsequently, the coated liquid crystals are
photo-cross-linked by radiating UV rays at 80 mW/cm.sup.2 for 30
seconds in a container filled with nitrogen, forming a .lamda./2
phase delay layer having optical properties as in the following
Table 6. Subsequently, a 60 .mu.m-thick Z-TAC film (Fuji Film
Corp.) is rubbed and orientation-treated in one direction, coated
with -A plate liquid crystals (n.sub.x<n.sub.y=n.sub.z, discotic
liquid crystal), and then dried in an oven at 60.degree. C. for 1
minutes to remove a coating solvent. Subsequently, the coated
crystal are photo-cross-linked by radiating UV rays at 80
mW/cm.sup.2 for 30 seconds in a container filled with nitrogen,
forming a .lamda./4 phase delay layer having optical properties as
in the following Table 6.
TABLE-US-00006 TABLE 6 In-plane phase Thickness retardation
Wavelength dispersion direction (R.sub.e) R.sub.e (450 nm)/ R.sub.e
(650 nm)/ retardation Thickness R.sub.e (550 nm) R.sub.e (550 nm)
R.sub.e (550 nm) (R.sub.th) (.mu.m) .lamda./2 240 1.12 0.95 110 2
.lamda./4 120 1.08 0.96 -56 1 .lamda./2 + 136 0.80 1.08 54 3
.lamda./4
Manufacture of Optical Film
Example 1
[0156] An adhesive (PS-47, Soken Chemical & Engineering Co.,
Ltd.) is coated on a surface of the polarization film according to
Preparation Example 1, and the polarization film is disposed to
face the phase delay layer according to Preparation Example 2.
Subsequently, the phase delay layer is transferred on the adhesive,
while the Z-TAC film is removed, manufacturing an optical film. The
polarization film has an optical axis of 0.degree., the phase delay
layer has a slow axis of 45.degree., and the optical film is about
34 .mu.m thick.
Example 2
[0157] An adhesive (PS-47, Soken Chemical & Engineering Co.,
Ltd.) is coated on a surface of the polarization film according to
Preparation Example 1, and then the polarization film is disposed
to face the .lamda./2 phase delay layer according to Preparation
Example 3. The .lamda./2 phase delay layer is transferred on the
adhesive, while the Z-TAC film is removed. Subsequently, an
adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is
coated on a surface of the .lamda./2 phase delay layer. The
.lamda./4 phase delay layer according to Preparation Example 3 is
disposed on the adhesive to face the .lamda./2 phase delay layer,
and then the .lamda./4 phase delay layer is transferred, while the
Z-TAC film is removed, manufacturing an optical film. The
polarization film has an optical axis of 0.degree., the .lamda./2
phase delay layer has a slow axis of 15.degree., the .lamda./4
phase delay layer has a slow axis of 75.degree., and the optical
film is about 38 .mu.m thick.
Example 3
[0158] An adhesive (PS-47, Soken Chemical & Engineering Co.,
Ltd.) is coated on a surface of the polarization film according to
Preparation Example 1, and then the polarization film is disposed
to face the .lamda./2 phase delay layer according to Preparation
Example 4. The .lamda./2 phase delay layer is transferred on the
adhesive, while the Z-TAC film is removed. Subsequently, an
adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is
coated on a surface of the .lamda./2 phase delay layer. The
.lamda./4 phase delay layer according to Preparation Example 3 is
disposed on the adhesive to face the .lamda./2 phase delay layer,
and then the .lamda./4 phase delay layer is transferred, while the
Z-TAC film is removed, manufacturing an optical film. The
polarization film has an optical axis of 0.degree., the .lamda./2
phase delay layer has a slow axis of 15.degree., the .lamda./4
phase delay layer has a slow axis of 75.degree., and the optical
film is about 38 .mu.m thick.
Example 4
[0159] An adhesive (PS-47, Soken Chemical & Engineering Co.,
Ltd.) is coated on a surface of the polarization film according to
Preparation Example 1, and then the polarization film is disposed
to face the .lamda./2 phase delay layer according to Preparation
Example 5. The .lamda./2 phase delay layer is transferred on the
adhesive, while the Z-TAC film is removed. Subsequently, an
adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is
coated on a surface of the .lamda./2 phase delay layer. The
.lamda./4 phase delay layer according to Preparation Example 3 is
disposed on the adhesive to face the .lamda./2 phase delay layer,
and then the .lamda./4 phase delay layer is transferred, while the
Z-TAC film is removed, manufacturing an optical film. The
polarization film has an optical axis of 0.degree., the .lamda./2
phase delay layer has a slow axis of 15.degree., the .lamda./4
phase delay layer has a slow axis of 75.degree., and the optical
film is about 38 .mu.m thick.
Example 5
[0160] An adhesive (PS-47, Soken Chemical & Engineering Co.,
Ltd.) is coated on a surface of the polarization film according to
Preparation Example 1, and then the polarization film is disposed
to face the .lamda./2 phase delay layer according to Preparation
Example 6. The .lamda./2 phase delay layer is transferred on the
adhesive, while the Z-TAC film is removed. Subsequently, an
adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is
coated on a surface of the .lamda./2 phase delay layer. The
.lamda./4 phase delay layer according to Preparation Example 3 is
disposed on the adhesive to face the .lamda./2 phase delay layer,
and then the .lamda./4 phase delay layer is transferred, while the
Z-TAC film is removed, manufacturing an optical film. The
polarization film has an optical axis of 0.degree., the .lamda./2
phase delay layer has a slow axis of 15.degree., the .lamda./4
phase delay layer has a slow axis of 75.degree., and the optical
film is about 38 .mu.m thick.
Example 6
[0161] An adhesive (PS-47, Soken Chemical & Engineering Co.,
Ltd.) is coated on a surface of the polarization film according to
Preparation Example 1, and then the polarization film is disposed
to face the .lamda./2 phase delay layer according to Preparation
Example 7. The .lamda./2 phase delay layer is transferred on the
adhesive, while the Z-TAC film is removed. Subsequently, an
adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is
coated on a surface of the .lamda./2 phase delay layer. The
.lamda./4 phase delay layer according to Preparation Example 3 is
disposed on the adhesive to face the .lamda./2 phase delay layer,
and then the .lamda./4 phase delay layer is transferred, while the
Z-TAC film is removed, manufacturing an optical film. The
polarization film has an optical axis of 0.degree., the .lamda./2
phase delay layer has a slow axis of 15.degree., the .lamda./4
phase delay layer has a slow axis of 75.degree., and the optical
film is about 38 .mu.m thick.
Comparative Example 1
[0162] An adhesive (PS-47, Soken Chemical & Engineering Co.,
Ltd.) is coated on a surface of the polarization film according to
Comparative Preparation Example 1, and the polarization film is
disposed to face the .lamda./2 phase delay layer according to
Preparation Example 1. The .lamda./2 phase delay layer is
transferred, while the Z-TAC film on the adhesive is removed.
Subsequently, an adhesive (PS-47, Soken Chemical & Engineering
Co., Ltd.) is coated on a surface of the .lamda./2 phase delay
layer. The .lamda./4 phase delay layer according to Preparation
Example 3 is disposed on the adhesive to face the .lamda./2 phase
delay layer, and then transferred thereon, while the Z-TAC film is
removed, manufacturing an optical film. The polarization film has
an optical axis of 0.degree., the .lamda./2 phase delay layer has a
slow axis of 15.degree., the .lamda./4 phase delay layer has a slow
axis of 75.degree., and the optical film is about 115 .mu.m
thick.
Comparative Example 2
[0163] A .lamda./4 phase delay layer having a 50 .mu.m-thick
inverse wavelength dispersion and optical properties as in the
following Table 7 (WRS, Teijin Ltd.) is prepared.
[0164] Then, an optical film is manufactured by coating an adhesive
(PS-47, Soken Chemical & Engineering Co., Ltd.) on a surface of
the polarization film according to Preparation Example 1, and
uniting the .lamda./4 phase delay layer with the polarization film.
The polarizing plate has an optical axis of 0.degree., the
.lamda./4 phase delay layer has a slow axis of 45.degree., and the
optical film is about 80 .mu.m thick.
TABLE-US-00007 TABLE 7 Thickness In-plane phase Wavelength
dispersion direction retardation (R.sub.e) R.sub.e (450 nm)/
R.sub.e (650 nm)/ retardation Thickness R.sub.e (550 nm) R.sub.e
(550 nm) R.sub.e (550 nm) (R.sub.th) (.mu.m) .lamda./4 146 0.89
1.03 73 50
Manufacture of Organic Light Emitting Display
Example 7
[0165] An organic light emitting display is manufactured by
attaching the optical film according to Example 1 on an organic
light emitting diode panel (Galaxy S4 panel, Samsung Display).
Example 8
[0166] An organic light emitting display is manufactured by
attaching the optical film according to Example 2 on an organic
light emitting diode panel (Galaxy S4 panel, Samsung Display).
Example 9
[0167] An organic light emitting display is manufactured by
attaching the optical film according to Example 3 on an organic
light emitting diode panel (Galaxy S4 panel, Samsung Display).
Example 10
[0168] An organic light emitting display is manufactured by
attaching the optical film according to Example 4 on an organic
light emitting diode panel (Galaxy S4 panel, Samsung Display).
Example 11
[0169] An organic light emitting display is manufactured by
attaching the optical film according to Example 5 on an organic
light emitting diode panel (Galaxy S4 panel, Samsung Display).
Example 12
[0170] An organic light emitting display is manufactured by
attaching the optical film according to Example 6 on an organic
light emitting diode panel (Galaxy S4 panel, Samsung Display).
Comparative Example 3
[0171] An organic light emitting display is manufactured by
attaching the optical film according to Comparative Example 1 on an
organic light emitting diode panel (Galaxy S4 panel, Samsung
Display).
Comparative Example 4
[0172] An organic light emitting display is manufactured by
attaching the optical film according to Comparative Example 2 on an
organic light emitting diode panel (Galaxy S4 panel, Samsung
Display).
Evaluation 1
[0173] Reflectance at front of the organic light emitting displays
according to Examples 7 and 8 and Comparative Examples 3 and 4 is
evaluated.
[0174] The reflectance at front is evaluated with a spectrum
colorimeter (CM-3600d, Konica Minolta Inc.) by supplying light with
a D65 light source under reflection of 8.degree. and
light-receiving of 2.degree..
[0175] The results are shown in Table 8.
TABLE-US-00008 TABLE 8 Comparative Comparative Example 7 Example 8
Example 3 Example 4 Reflectance (%) 5.2 5.1 5.0 5.2
[0176] Referring to Table 8, the organic light emitting displays
according to Examples 7 and 8 showed equivalent reflectance at
front to that of the organic light emitting displays according to
Comparative Examples 3 and 4. Accordingly, the organic light
emitting displays according to Examples 7 and 8 have a thin film
shape but no influence on display characteristics by remarkably
decreasing thickness of an optical film while showing equivalent
reflectance at front.
Evaluation 2
[0177] Reflectance and reflective color at front of the organic
light emitting displays according to Examples 8 to 12 and
Comparative Example 4 are evaluated.
[0178] The reflectance and the reflective color at front are
evaluated with a spectrum colorimeter (DMS, Display Measurement
Systems, Instrument Systems) by supplying light with a D65 light
source under reflection of 8.degree..
[0179] The reflective color may be represented using CIE-Lab color
coordinates. The positive value a* denotes red, the negative value
a* denotes green, the positive value b* denotes yellow, and the
negative value b* denotes blue. In the CIE-Lab color coordinates,
the larger the absolute values of a* and b* are, the stronger the
colors corresponding thereto are.
[0180] The results are shown in Table 9.
TABLE-US-00009 TABLE 9 Front reflectance (%) a* b* .DELTA. a*b*
Example 8 0.7 -0.9 -6.2 6.3 Example 9 0.7 -0.4 -4.2 4.3 Example 10
0.6 -1.3 -5.1 5.3 Example 11 0.6 0.7 -5.1 5.2 Example 12 0.6 0.1
-4.1 4.1 Comparative 0.7 -1.4 -9.0 9.1 Example 4 .DELTA. a*b* =
{square root over (a*.sup.3 + b*.sup.2)}
[0181] Referring to Table 9, the organic light emitting displays
according to Examples 8 to 12 showed equivalent or improved
reflectance at front and smaller reflective color values at front
than that of the organic light emitting displays according to
Comparative Example 4. The smaller reflective color value means
that a color sense by reflection may be closer to black and a
change of a color sense may be small and a visibility by reflection
due to an external light may be improved. For example, the organic
light emitting displays according to Examples 8 to 12 may have
reflective color values at front satisfying
0.ltoreq..DELTA.a*b*.ltoreq.9.
[0182] Accordingly, the organic light emitting displays according
to Examples 8 to 12 have a thin film shape but improved display
characteristics by remarkably decreasing thickness of an optical
film while showing equivalent or improved reflectance and improved
reflective color at front.
Evaluation 3
[0183] Reflectance and reflective color at side of the organic
light emitting displays according to Examples 8 to 12 and
Comparative Example 4 are evaluated.
[0184] The reflectance and the reflective color at side are
evaluated with a spectrum colorimeter (DMS, Display Measurement
Systems, Instrument Systems) by supplying light with a D65 light
source under reflection of 45.degree..
[0185] The results are shown in Table 10.
TABLE-US-00010 TABLE 10 Side reflectance (%) a* b* .DELTA. a*b*
Example 8 1.3 -3.2 -0.5 3.3 Example 9 1.3 -3.5 0.9 4.0 Example 10
0.8 -1.2 -3.2 3.6 Example 11 1.0 -1.1 -1.4 2.0 Example 12 0.8 -0.6
-0.9 1.5 Comparative 1.2 -3.3 -3.3 5.5 Example 4 .DELTA. a*b* =
{square root over (a*.sup.3 + b*.sup.2)}
[0186] Referring to Table 10, the organic light emitting displays
according to Examples 8 to 12 showed equivalent or improved
reflectance at side and smaller reflective color values at side
than that of the organic light emitting displays according to
Comparative Example 4. For example, the organic light emitting
displays according to Examples 8 to 12 may have reflective color
values at side satisfying 0.ltoreq..DELTA.a*b*.ltoreq.5.
[0187] Further, it is confirmed that the organic light emitting
displays according to Examples 8 to 12 showed a color sense closer
to black than that of the organic light emitting displays according
to Comparative Example 4.
[0188] Accordingly, the organic light emitting displays according
to Examples 8 to 12 have a thin film shape but improved display
characteristics by remarkably decreasing thickness of an optical
film while showing equivalent or improved reflectance and improved
reflective color at side.
Evaluation 4
[0189] Optical durability of the organic light emitting displays
according to Example 8 and Comparative Example 3 is evaluated.
[0190] The optical durability evaluation includes a thermal
stability evaluation and a high temperature/high humidity
evaluation, and herein, the thermal stability evaluation is
performed by allowing the organic light emitting displays according
to Example 8 and Comparative Example 3 to stand at 85.degree. C.
for 500 hours and measuring their light transmittance and
variations of their degrees of polarization, and the high
temperature/high humidity evaluation is performed by allowing the
organic light emitting displays according to Example 8 and
Comparative Example 3 to stand at 60.degree. C. under humidity of
95% for 500 hours and measuring their light transmittance and
variations of their degrees of polarization.
[0191] The results are shown in Table 11.
TABLE-US-00011 TABLE 11 Evaluation at Evaluation of high
temperature and thermal stability at high humidity 85.degree. C.
and 500 h (60.degree. C., 95%, 500 h) Variations of Variations of
Variations Variations of light degree of of light degree of
transmittance polarization transmittance polarization (%) (%) (%)
(%) Example 8 0.36 0.37 0.42 0.09 Comparative 0.9 3 6 20 Example
3
[0192] Referring to Table 11, the organic light emitting display
according to Example 8 shows excellent thermal stability and
excellent optical durability in a high temperature/high humidity
environment.
[0193] While the invention has been described in connection with
what is presently considered to be practical exemplary embodiments,
it is to be understood that the invention is not limited to the
disclosed embodiments, but, on the contrary, is intended to cover
various modifications and equivalent arrangements included within
the spirit and scope of the appended claims.
* * * * *