U.S. patent application number 16/449900 was filed with the patent office on 2019-10-10 for method of producing polarizing plate.
This patent application is currently assigned to NITTO DENKO CORPORATION. The applicant listed for this patent is NITTO DENKO CORPORATION. Invention is credited to Keisuke Kimura, Yoshitsugu Kitamura, Hiroki Kuramoto, Shinobu Nagano, Eiko Suefusa, Youichirou Sugino, Katsunori Takada.
Application Number | 20190310406 16/449900 |
Document ID | / |
Family ID | 58634503 |
Filed Date | 2019-10-10 |
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United States Patent
Application |
20190310406 |
Kind Code |
A1 |
Takada; Katsunori ; et
al. |
October 10, 2019 |
METHOD OF PRODUCING POLARIZING PLATE
Abstract
There is provided a polarizing plate excellent in durability. A
method of producing a polarizing plate according to an embodiment
of the present invention includes: preparing a polarizing film
laminate including a polarizer and a protective film arranged on at
least one side of the polarizer; and shrinking the polarizing film
laminate.
Inventors: |
Takada; Katsunori;
(Ibaraki-shi, JP) ; Nagano; Shinobu; (Ibaraki-shi,
JP) ; Suefusa; Eiko; (Ibaraki-shi, JP) ;
Kitamura; Yoshitsugu; (Ibaraki-shi, JP) ; Kimura;
Keisuke; (Ibaraki-shi, JP) ; Kuramoto; Hiroki;
(Ibaraki-shi, JP) ; Sugino; Youichirou;
(Ibaraki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NITTO DENKO CORPORATION |
Osaka |
|
JP |
|
|
Assignee: |
NITTO DENKO CORPORATION
Osaka
JP
|
Family ID: |
58634503 |
Appl. No.: |
16/449900 |
Filed: |
June 24, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15332561 |
Oct 24, 2016 |
|
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16449900 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 63/00 20130101;
B32B 2307/42 20130101; G02B 5/305 20130101; B29C 61/02
20130101 |
International
Class: |
G02B 5/30 20060101
G02B005/30; B29C 63/00 20060101 B29C063/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 4, 2015 |
JP |
2015-216398 |
Claims
1. A method of producing a polarizing plate, comprising: preparing
a polarizing film laminate including a polarizer and a protective
film arranged on at least one side of the polarizer; shrinking the
polarizing film laminate; and then cutting the shrunk polarizing
film laminate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a Continuation of U.S. patent application Ser. No.
15/332,561, filed Oct. 24, 2016, which claims priority under 35
U.S.C. Section 119 to Japanese Patent Application No. 2015-216398
filed on Nov. 4, 2015, the entire contents of which is herein
incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a method of producing a
polarizing plate.
2. Description of the Related Art
[0003] A polarizing plate has been used in an image display
apparatus (e.g., a liquid crystal display apparatus) of a cellular
phone, a notebook personal computer, or the like. In recent years,
the use of the polarizing plate in, for example, a meter display
portion of an automobile or a smart watch has been desired, and
hence the formation of the polarizing plate into a shape other than
a rectangular shape and the formation of a through-hole in the
polarizing plate have been desired. However, when any such form is
adopted, a problem in terms of durability is liable to occur. With
a view to improving the durability, for example, there has been
proposed a method involving thermally treating a polarizer at a
temperature of 95.degree. C. or more, and laminating a protective
film on the thermally treated polarizer to provide a polarizing
plate (see Japanese Patent Application Laid-open No. Hei 7
(1995)-333425). However, a further improvement in durability has
been required.
SUMMARY OF THE INVENTION
[0004] The present invention has been made to solve the problem,
and a primary object of the present invention is to provide a
polarizing plate excellent in durability.
[0005] A method of producing a polarizing plate according to an
embodiment of the present invention includes: preparing a
polarizing film laminate including a polarizer and a protective
film arranged on at least one side of the polarizer; and shrinking
the polarizing film laminate.
[0006] In one embodiment of the present invention, the shrinking
the polarizing film laminate is performed in a transmission axis
direction of the polarizer by 0.2% or more.
[0007] In one embodiment of the present invention, the method
further includes cutting the polarizing film laminate.
[0008] According to another aspect of the present invention, there
is provided a polarizing plate. The polarizing plate is obtained by
the production method as described above.
[0009] According to the present invention, the polarizing plate
excellent in durability can be obtained by shrinking the polarizing
film laminate obtained by laminating the polarizer and the
protective film.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a sectional view of a polarizing film laminate
according to one embodiment of the present invention.
[0011] FIG. 2 is a plan view of a polarizing plate according to one
embodiment of the present invention.
[0012] FIG. 3A is a photograph for showing the periphery of a
through-hole of the polarizing plate of Example 1 after a heat
cycle test, FIG. 3B is a photograph for showing the periphery of a
through-hole of the polarizing plate of Example 2 after a heat
cycle test, FIG. 3C is a photograph for showing the periphery of a
through-hole of the polarizing plate of Example 3 after a heat
cycle test, and FIG. 3D is a photograph for showing the periphery
of a through-hole of the polarizing plate of Comparative Example 1
after a heat cycle test.
[0013] FIG. 4A is a photograph for showing the state of the
periphery of an end side of the polarizing plate along the
transmission axis direction of the test sample of Example 1 after
the heat cycle test, and FIG. 4B is a photograph for showing the
state of the periphery of an end side of the polarizing plate along
the absorption axis direction thereof.
[0014] FIG. 5A is a photograph for showing the state of the
periphery of an end side of the polarizing plate along the
transmission axis direction of the test sample of Comparative
Example 1 after the heat cycle test, and FIG. 5B is a photograph
for showing the state of the periphery of an end side of the
polarizing plate along the absorption axis direction thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Hereinafter, embodiments of the present invention are
described. However, the present invention is not limited to these
embodiments.
[0016] A method of producing a polarizing plate according to an
embodiment of the present invention includes: preparing a
polarizing film laminate including a polarizer and a protective
film arranged on at least one side of the polarizer; and shrinking
the polarizing film laminate.
A. Polarizing Film Laminate
[0017] FIG. 1 is a sectional view of a polarizing film laminate
according to one embodiment of the present invention. A polarizing
film laminate 10 includes a polarizer 11, a first protective film
21 arranged on one side of the polarizer 11, and a second
protective film 22 arranged on the other side of the polarizer 11.
The protective films 21 and 22 are each typically bonded to the
surface of the polarizer 11 through intermediation of an adhesive
layer, though the layer is not shown. Although the protective films
are arranged on both sides of the polarizer in this illustrated
example, a protective film may be arranged only on one side
thereof.
A-1. Polarizer
[0018] The polarizer typically includes a resin film containing a
dichromatic substance. Examples of the dichromatic substance
include iodine and an organic dye. The substances may be used alone
or in combination. Of those, iodine is preferably used.
[0019] Any appropriate resin may be used as a resin for forming the
resin film. A hydrophilic resin (e.g., a polyvinyl alcohol
(PVA)-based resin) is preferably used as the resin. Examples of the
PVA-based resin include polyvinyl alcohol and an ethylene-vinyl
alcohol copolymer. The polyvinyl alcohol is obtained by saponifying
polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained
by saponifying an ethylene-vinyl acetate copolymer. The
saponification degree of the PVA-based resin is typically from 85
mol % to 100 mol %, preferably 95.0 mol % or more, more preferably
99.0 mol % or more, particularly preferably 99.93 mol % or more.
The saponification degree may be determined in conformity with JIS
K 6726-1994. The use of the PVA-based resin having such
saponification degree can provide a polarizer excellent in
durability.
[0020] The average polymerization degree of the PVA-based resin may
appropriately be selected depending on purposes. The average
polymerization degree is typically from 1,000 to 10,000, preferably
from 1,200 to 6,000, more preferably from 2,000 to 5,000. The
average polymerization degree may be determined in conformity with
JIS K 6726-1994.
[0021] The polarizer preferably shows absorption dichroism in the
wavelength range of from 380 nm to 780 nm. The single axis
transmittance (Ts) of the polarizer is preferably 40% or more, more
preferably 41% or more, still more preferably 42% or more,
particularly preferably 43% or more. A theoretical upper limit for
the single axis transmittance is 50%, and a practical upper limit
therefor is 46%. In addition, the single axis transmittance (Ts) is
a Y value measured with the two-degree field of view (C light
source) of JIS Z 8701 and subjected to visibility correction, and
may be measured with, for example, a spectrophotometer
(manufactured by JASCO Corporation, V7100). The polarization degree
of the polarizer is preferably 99.8% or more, more preferably 99.9%
or more, still more preferably 99.95% or more.
[0022] The thickness of the polarizer may be set to any appropriate
value. The thickness is typically from 1 .mu.m to 80 .mu.m,
preferably from 3 .mu.m to 40 .mu.m.
[0023] The polarizer may be typically obtained by subjecting the
resin film to treatments, such as a swelling treatment, a
stretching treatment, a dyeing treatment with the dichromatic
substance, a cross-linking treatment, a washing treatment, and a
drying treatment. The number of times of each of the treatments,
the order in which the treatments are performed, the timings of the
treatments, and the like may appropriately be set. When the resin
film is subjected to each of the treatments, the film may be a
resin layer formed on a substrate.
[0024] The cross-linking treatment is performed by, for example,
bringing a boric acid solution (e.g., an aqueous solution of boric
acid) into contact with the resin film. In addition, when a wet
stretching system is adopted in the stretching treatment, the
stretching is preferably performed while a boric acid solution is
brought into contact with the resin film. In ordinary cases, the
resin film is uniaxially stretched at from 3 times to 7 times from
the viewpoint that excellent polarization characteristics are
obtained. A stretching direction in the stretching treatment may
correspond to the absorption axis direction of the polarizer to be
obtained. The transmission axis direction thereof may be
perpendicular to the absorption axis direction. In one embodiment,
while an elongated resin film is conveyed in its lengthwise
direction, the film is stretched in the conveying direction
(machine direction: MD). In this case, the absorption axis
direction of the polarizer to be obtained may be the lengthwise
direction (MD), and the transmission axis direction thereof may be
a widthwise direction (transverse direction: TD).
A-2. Protective Film
[0025] As the formation materials of the protective film, there are
given, for example, a cellulose-based resin, such as diacetyl
cellulose or triacetyl cellulose (TAC), a (meth)acrylic resin, a
cycloolefin-based resin, an olefin-based resin, such as
polypropylene, an ester-based resin, such as a polyethylene
terephthalate-based resin, a polyamide-based resin, a
polycarbonate-based resin, and copolymer resins thereof. The term
"(meth)acrylic resin" refers to an acrylic resin and/or a
methacrylic resin.
[0026] The thickness of the protective film is preferably from 10
.mu.m to 200 .mu.m. A surface-treated layer may be formed on one
side of the protective film (side on which the polarizer is not
arranged). Specifically, the side may be subjected to a hard coat
treatment, an antireflection treatment, or a treatment intended for
diffusion or anti-glaring. In addition, the protective film may
function as a retardation film. When the protective films are
arranged on both sides of the polarizer like the illustrated
example, the constructions (including a formation material and a
thickness) of both the films may be identical to each other, or may
be different from each other.
A-3. Others
[0027] Any appropriate adhesive may be adopted as an adhesive to be
used in the bonding of the protective film. For example, an aqueous
adhesive, a solvent-based adhesive, or an active energy ray-curable
adhesive is used. An adhesive containing a PVA-based resin is
preferably used as the aqueous adhesive.
B. Shrinkage
[0028] As described above, the method includes shrinking the
polarizing film laminate. The shrinkage of the polarizing film
laminate can provide a polarizing plate excellent in durability.
Specifically, a shrunk polarizing plate shows an extremely small
change in shape due to a change in external environment, and hence
when the polarizing plate is bonded to any other member (e.g., the
glass substrate of a liquid crystal cell or the like) through
intermediation of a pressure-sensitive adhesive layer, an influence
on the adjacent pressure-sensitive adhesive layer is extremely
small. Accordingly, a change in shape of the pressure-sensitive
adhesive layer due to the change in external environment is
suppressed, and hence the occurrence of a stress between the
respective members (e.g., a stress produced when the modulus of
elasticity of the pressure-sensitive adhesive layer increases at
low temperature) can be prevented. As a result, a crack does not
occur in the polarizing plate and hence the polarizing plate can
have extremely excellent durability.
[0029] A method for the shrinkage is typically, for example, a
method involving heating the polarizing film laminate. A heating
temperature is, for example, from 50.degree. C. to 120.degree. C.,
preferably from 70.degree. C. to 90.degree. C. When the temperature
falls within such range, the polarizing film laminate can be
efficiently shrunk while its optical characteristics (e.g., a hue,
a transmittance, and a polarization degree) are secured. A heating
time is, for example, from 1 hour to 100 hours, preferably 2 hours
or more, more preferably 10 hours or more. The heating may be
performed in one stage, or maybe performed in a plurality of
stages. In addition, the heating temperature may be kept
substantially constant, or may be changed continuously or in a
stepwise manner.
[0030] A shrinkage ratio is preferably 0.2% or more, more
preferably 0.3% or more in, for example, the transmission axis
direction of the polarizer in the polarizing film laminate.
Meanwhile, the shrinkage ratio in the transmission axis direction
is, for example, 0.6% or less. With such shrinkage ratio, it can be
judged that the polarizing film laminate is shrunk to a sufficient
level. The polarizing film laminate may shrink in its absorption
axis direction to a larger extent than in the transmission axis
direction, and hence at the initial stage of the shrinkage, a
dimension in the transmission axis direction of the polarizing film
laminate apparently increases for the time being in some cases. In
any such case, as the shrinkage progresses, the dimension in the
transmission axis direction may reduce from a dimension at the time
of the initiation of the shrinkage (at the time of the initiation
of the heating).
[0031] A shrinkage ratio in the absorption axis direction of the
polarizing film laminate is preferably 0.3% or more, more
preferably 0.4% or more. Meanwhile, the shrinkage ratio in the
absorption axis direction is, for example, 1.0% or less. The
shrinkage ratio may be determined from the following equation.
Shrinkage ratio (%)={1-(dimension after heating/dimension before
heating)}.times.100
C. Cutting
[0032] The polarizing plate of the present invention can be formed
into a desired shape because the polarizing plate has excellent
durability. A method of forming the polarizing plate into the
desired shape is typically, for example, a method involving cutting
(punching) the polarizing film laminate. The cutting may be
performed before the shrinkage of the polarizing film laminate, or
may be performed after the shrinkage of the polarizing film
laminate. Excellent durability can be obtained irrespective of
whether the cutting is performed before the shrinkage or performed
after the shrinkage. The cutting is preferably performed after the
shrinkage from the viewpoint that the forming into the desired
shape is performed more accurately.
[0033] Any appropriate method may be adopted as a cutting
(punching) method. For example, a method involving irradiating the
laminate with laser light or a method involving using a cutting
blade (punching die), such as a Thomson blade or a pinnacle blade,
is given. The laser light irradiation provides a smooth cut surface
and can suppress the occurrence of the starting point of a crack
(initial crack), and hence can contribute to a further improvement
in durability. Even when the cutting blade is used (even when the
initial crack occurs), the shrinkage can provide excellent
durability.
[0034] Any appropriate laser may be adopted as the laser as long as
the polarizing film laminate (polarizing plate) can be cut. A laser
that can emit light having a wavelength in the range of from 150 nm
to 11 .mu.m is preferably used. Specific examples thereof include a
gas laser, such as a CO.sub.2 laser, a solid laser, such as an YAG
laser, and a semiconductor laser. Of those, a CO.sub.2 laser is
preferably used.
[0035] A condition for the laser light irradiation may be set to
any appropriate condition depending on, for example, the laser to
be used. When the CO.sub.2 laser is used, an output condition is
preferably from 10 W to 1,000 W, more preferably from 100 W to 400
W.
D. Polarizing Plate
[0036] FIG. 2 is a plan view of a polarizing plate according to one
embodiment of the present invention. A polarizing plate 100 is
suitably used in the meter panel of an automobile. The polarizing
plate 100 includes a first display portion 50 and a second display
portion 60 that are continuously arranged, and through-holes 51 and
61 for fixing various meter needles are formed around the centers
of the respective display portions. The diameter of each of the
through-holes is, for example, from 0.5 mm to 100 mm. The outer
edge of each of the display portions 50 and 60 is formed into an
arc shape along the rotational direction of a meter needle.
[0037] When a through-hole is formed like the illustrated example,
the position of the through-hole may appropriately be set depending
on, for example, the applications of the polarizing plate. The
crack is liable to occur from the peripheral edge of the
through-hole serving as a starting point, and the tendency may be
more remarkable as the position of the through-hole becomes more
distant from the outer edge of the polarizing plate. As a result,
as the position of the through-hole becomes more distant from the
outer edge of the polarizing plate (e.g., its distance from the
outer edge of the polarizing plate is 15 mm or more), a
durability-improving effect exhibited by the shrinkage can be more
significantly obtained. Similarly to the peripheral edge of the
through-hole, a site whose outer edge forms a V-shape (including an
R-shape) that is convex inward in a plane direction, such as a
boundary portion 41 or 42 between the respective display portions,
is also liable to serve as the starting point of the crack.
[0038] The polarizing plate of the present invention is not limited
to the construction of the illustrated example and may be
appropriately changed. For example, the shape of the polarizing
plate, the presence or absence of the through-holes, the shapes and
sizes of the through-holes, and the number and formation positions
of the through-holes may appropriately be changed.
[0039] The polarizing plate of the present invention is bonded to
any other member (e.g., the glass substrate of a liquid crystal
cell or the like) through intermediation of, for example, a
pressure-sensitive adhesive layer. The thickness of the
pressure-sensitive adhesive layer is preferably from 4 .mu.m to 50
.mu.m. An acrylic pressure-sensitive adhesive is preferably used as
a pressure-sensitive adhesive forming the pressure-sensitive
adhesive layer.
[0040] Hereinafter, the present invention is specifically described
by way of Examples. However, the present invention is not limited
to these Examples. A dimensional change ratio is a value calculated
from the following equation.
Dimensional change ratio (%)={(dimension after heating/dimension
before heating)-1}.times.100
EXAMPLE 1
(Production of Polarizing Film Laminate Sheet)
[0041] A film (thickness: 28 .mu.m) obtained by incorporating
iodine into an elongated PVA-based resin film and uniaxially
stretching the film in its lengthwise direction (MD) was used as a
polarizer.
[0042] A PVA-based adhesive was applied to one side of the
polarizer so that its thickness after drying became 100 nm, and an
elongated TAC film having a thickness of 40 .mu.m was bonded to the
polarizer so that their lengthwise directions were aligned with
each other.
[0043] Subsequently, a PVA-based adhesive was applied to the other
side of the polarizer so that its thickness after drying became 100
nm, and an elongated acrylic film having a thickness of 30 .mu.m
was bonded to the polarizer so that their lengthwise directions
were aligned with each other.
[0044] Thus, a polarizing film laminate sheet having a construction
"TAC film/polarizer/acrylic film" was obtained.
[0045] The resultant polarizing film laminate sheet was cut with a
CO.sub.2 laser (wavelength: 9.35 .mu.m, output: 150 W) to provide a
cut piece of a size measuring 112 mm by 112 mm, the cut piece
having a through-hole having a diameter of 2 mm formed in a site
distant from its outer edge by 55 mm.
[0046] The resultant cut piece was placed under an atmosphere at
85.degree. C. for 50 hours to provide a polarizing plate. The
polarizing plate had a dimensional change ratio of -0.74%
(shrinkage ratio of 0.74%) in its absorption axis direction and a
dimensional change ratio of -0.44% (shrinkage ratio of 0.44%) in
its transmission axis direction, the dimensional change ratios each
serving as a ratio of a dimension after the heating to that before
the heating. The dimensional change ratios each serving as a ratio
of a dimension after the heating to that before the heating were
each determined by: separately preparing a cut piece cut out of the
polarizing film laminate sheet into a size measuring 100 mm by 100
mm (no through-hole was formed in the cut piece); and measuring the
position of a corner of the cut piece. In this case, the cut piece
was cut out of the sheet so that a pair of sides opposite to each
other corresponded to the transmission axis direction of the
polarizer and another pair of sides opposite to each other
corresponded to the absorption axis direction of the polarizer.
EXAMPLE 2
[0047] A polarizing plate was obtained in the same manner as in
Example 1 except that the resultant cut piece was placed under an
atmosphere at 85.degree. C. for 5 hours. The polarizing plate had a
dimensional change ratio of -0.45% (shrinkage ratio of 0.45%) in
its absorption axis direction and a dimensional change ratio of
-0.37% (shrinkage ratio of 0.37%) in its transmission axis
direction, the dimensional change ratios each serving as a ratio of
a dimension after the heating to that before the heating, and each
being measured by the same method as that of Example 1.
EXAMPLE 3
[0048] A polarizing plate was obtained in the same manner as in
Example 1 except that the resultant cut piece was placed under an
atmosphere at 85.degree. C. for 2.5 hours. The polarizing plate had
a dimensional change ratio of -0.34% (shrinkage ratio of 0.34%) in
its absorption axis direction and a dimensional change ratio of
-0.25% (shrinkage ratio of 0.25%) in its transmission axis
direction, the dimensional change ratios each serving as a ratio of
a dimension after the heating to that before the heating, and each
being measured by the same method as that of Example 1.
EXAMPLE 4
[0049] A polarizing plate was obtained in the same manner as in
Example 1 except that: the size of the cut piece was set to 52 mm
by 52 mm; and the through-hole was formed in a site distant from
the outer edge of the cut piece by 25 mm.
COMPARATIVE EXAMPLE 1
[0050] A polarizing plate was obtained in the same manner as in
Example 1 except that the cut piece was not heated.
COMPARATIVE EXAMPLE 2
[0051] A polarizing plate was obtained in the same manner as in
Example 4 except that the cut piece was not heated.
[0052] The durability of the resultant polarizing plate was
evaluated by a heat cycle test (also referred to as heat shock (HS)
test). Specifically, a test sample was obtained by bonding the
resultant polarizing plate to a glass plate with an acrylic
pressure-sensitive adhesive (thickness: 20 .mu.m). The sample was
left to stand under an environment at -40.degree. C. for 30 minutes
and then left to stand under an environment at 85.degree. C. for 30
minutes. The foregoing operation was defined as one cycle and the
cycle was repeated 100 times. After that, whether or not a crack
occurred in the polarizing plate was observed.
[0053] FIG. 3A to FIG. 3D are photographs obtained by observing the
peripheries of the through-holes of the polarizing plates of
Examples 1 to 3 and Comparative Example 1 after the HS tests with
an optical microscope (manufactured by Olympus Corporation, MX61,
magnification: 5). In Comparative Example 1 (FIG. 3D), a crack that
can be visually recognized with the eyes in a clear manner is
observed. In contrast, in Example 1 (FIG. 3A), the occurrence of a
crack (including a microcrack) is not observed. In each of Examples
2 and 3 (FIG. 3B and FIG. 3C), a microcrack that cannot be visually
recognized with the eyes in a clear manner is observed, but the
occurrence of a crack is suppressed as compared to Comparative
Example 1. The cracks each occur along a stretching direction.
[0054] In Example 4, as in Example 1, the occurrence of a crack
(including a microcrack) is not observed. In Comparative Example 1,
the crack extends from the through-hole serving as a starting point
to an end side of the polarizing plate. In contrast, in Comparative
Example 2, a crack length is 12 mm.
[0055] FIG. 4A and FIG. 4B are each a photograph for showing the
state of an end portion of the polarizing plate of the test sample
of Example 1 after the HS test, and FIG. 5A and FIG. 5B are each a
photograph for showing the state of an end portion of the
polarizing plate of the test sample of Comparative Example 1 after
the HS test. In Comparative Example 1, a region in which the
pressure-sensitive adhesive layer used at the time of the bonding
of the polarizing plate to the glass plate is exposed is
formed.
[0056] The polarizing plate of the present invention can be
suitably used not only in an image display apparatus (a liquid
crystal display apparatus or an organic EL device) of a rectangular
shape but also in, for example, an image display portion of a
particular shape typified by the meter display portion of an
automobile or a smart watch.
[0057] Many other modifications will be apparent to and be readily
practiced by those skilled in the art without departing from the
scope and spirit of the invention. It should therefore be
understood that the scope of the appended claims is not intended to
be limited by the details of the description but should rather be
broadly construed.
* * * * *