U.S. patent application number 11/283902 was filed with the patent office on 2006-07-06 for optical filter for image display devices and manufacturing method thereof.
This patent application is currently assigned to Samsung Corning Co., Ltd.. Invention is credited to Sung Hen Cho, Euk Che Hwang, Jin Young Kim, Ho Chul Lee, Chang Ho Noh, Ki Yong Song.
Application Number | 20060144713 11/283902 |
Document ID | / |
Family ID | 36639113 |
Filed Date | 2006-07-06 |
United States Patent
Application |
20060144713 |
Kind Code |
A1 |
Song; Ki Yong ; et
al. |
July 6, 2006 |
Optical filter for image display devices and manufacturing method
thereof
Abstract
An optical filter that may include a transparent substrate, a
photocatalytic film formed on the back surface of the transparent
substrate, a metal pattern formed by selectively exposing the
photocatalytic film to light and growing a metal crystal thereon by
plating, and a near-infrared ray shielding and photoselective
absorbing layer formed on the metal pattern. Since the optical
filter may exhibit superior color reproduction and excellent
shielding performance against electromagnetic waves, near-infrared
rays and neon light, it may be applied to a variety of image
display devices, e.g., PDPs.
Inventors: |
Song; Ki Yong; (Seoul,
KR) ; Kim; Jin Young; (Suwon-si, KR) ; Noh;
Chang Ho; (Suwon-si, KR) ; Cho; Sung Hen;
(Seoul, KR) ; Hwang; Euk Che; (Osan-si, KR)
; Lee; Ho Chul; (Suwon-si, KR) |
Correspondence
Address: |
BUCHANAN INGERSOLL PC;(INCLUDING BURNS, DOANE, SWECKER & MATHIS)
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Samsung Corning Co., Ltd.
Suwon-si
KR
|
Family ID: |
36639113 |
Appl. No.: |
11/283902 |
Filed: |
November 22, 2005 |
Current U.S.
Class: |
205/118 |
Current CPC
Class: |
C23C 18/2086 20130101;
C23C 18/1605 20130101; C23C 18/208 20130101; C23C 18/1608 20130101;
C23C 18/1868 20130101; C23C 18/204 20130101; C23C 18/1612 20130101;
C25D 5/022 20130101; C23C 18/405 20130101; C23C 18/1889 20130101;
C23C 18/1893 20130101; C25D 5/54 20130101 |
Class at
Publication: |
205/118 |
International
Class: |
C25D 5/02 20060101
C25D005/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 25, 2004 |
KR |
2004-97642 |
Claims
1. An optical filter for image display devices, comprising: a
transparent substrate; a photocatalytic film formed on a back
surface of the transparent substrate; a metal pattern formed by
selectively exposing the photocatalytic film to light and growing a
metal crystal thereon by plating; and a near-infrared ray shielding
and photoselective absorbing layer formed on the metal pattern.
2. The optical filter according to claim 1, further comprising an
antireflective film formed on a front surface of the transparent
substrate.
3. The optical filter according to claim 1, wherein the
near-infrared ray shielding and photoselective absorbing layer
comprises: at least one near-infrared ray absorbing material
selected from the group consisting of mixed dyes of a nickel
complex and a diammonium, compound dyes containing copper ions and
zinc ions, cyanine dyes, anthraquinone dyes, squarylium compounds,
azomethine compounds, oxonol compounds, azo compounds, and
benzylidene compounds; and at least one neon light blocking
material selected from the group consisting of
octaphenyltetraazaporphyrin and tetraazaporphyrin derivative dyes
in which one ligand selected from ammonia, water and halogen is
coordinately bonded to a central metal (M) atom of an
octaphenyltetraazaporphyrin or tetraazaporphyrin ring.
4. The optical filter according to claim 1, wherein the
near-infrared ray shielding and photoselective absorbing layer has
a thickness of 1-20 .mu.m.
5. The optical filter according to claim 1 wherein the transparent
substrate is a glass substrate or a transparent plastic substrate
selected from the group consisting of acrylic resins, polyesters,
polycarbonates, polyethylenes, polyethersulfones, olefin-maleimide
copolymers, and norbornene-based resins.
6. The optical filter according to claim 2, wherein the
near-infrared ray shielding and photoselective absorbing layer
comprises: at least one near-infrared ray absorbing material
selected from the group consisting of mixed dyes of a nickel
complex and a diammonium, compound dyes containing copper ions and
zinc ions, cyanine dyes, anthraquinone dyes, squarylium compounds,
azomethine compounds, oxonol compounds, azo compounds, and
benzylidene compounds; and at least one neon light blocking
material selected from the group consisting of
octaphenyltetraazaporphyrin and tetraazaporphyrin derivative dyes
in which one ligand selected from ammonia, water and halogen is
coordinately bonded to a central metal (M) atom of an
octaphenyltetraazaporphyrin or tetraazaporphyrin ring.
7. The optical filter according to claim 2, wherein the
near-infrared ray shielding and photoselective absorbing layer has
a thickness of 1-20 .mu.m.
8. The optical filter according to claim 2 wherein the transparent
substrate is a glass substrate or a transparent plastic substrate
selected from the group consisting of acrylic resins, polyesters,
polycarbonates, polyethylenes, polyethersulfones, olefin-maleimide
copolymers, and norbornene-based resins.
9. The optical filter according to claim 2, wherein the
antireflective film comprises at least one material selected from
the group consisting of silicon-based organic materials,
fluorine-based organic materials, indium tin oxide (ITO), ZnO,
Al-doped ZnO, TiO.sub.2, and ZrO.
10. A method for manufacturing an optical filter for image display
devices, comprising the steps of: coating a photocatalytic compound
on a back surface of a transparent substrate to form a
photocatalytic film (a first step); selectively exposing the
photocatalytic compound to light and growing a metal crystal
thereon by plating to form a metal pattern (a second step); and
coating a resin containing a near-infrared ray shielding material
and a photoselective absorbing material on the metal pattern to
form a near-infrared ray shielding and photoselective absorbing
layer (a third step).
11. The method according to claim 10, further comprising the step
of laminating an antireflective film on a front surface of the
transparent substrate.
12. The method according to claim 10, wherein the first step
includes the sub-steps of: coating a Ti-containing organic compound
as the photocatalytic compound on the transparent substrate to form
a Ti-containing organic compound layer; and forming a
photosensitizer-containing water-soluble polymer layer on the
Ti-containing organic compound layer.
13. The method according to claim 10, wherein the metal pattern is
formed by growing two or more metals by plating in the second
step.
14. The method according to claim 10, wherein the coating step
comprises preparing a coating solution, wherein the coating
solution is prepared by mixing a near-infrared ray absorbing
material, a photoselective absorbing material and a binder resin in
an organic solvent; the near-infrared ray absorbing material being
at least one material selected from the group consisting of mixed
dyes of a nickel complex and a diammonium, compound dyes containing
copper ions and zinc ions, cyanine dyes, anthraquinone dyes,
squarylium compounds, azomethine compounds, oxonol compounds, azo
compounds, and benzylidene compounds; and the photoselective
absorbing material being at least one materail being selected from
the group consisting of octaphenyltetraazaporphyrin and
tetraazaporphyrin derivative dyes in which one ligand selected from
ammonia, water and halogen is coordinately bonded to a central
metal (M) atom of an octaphenyltetraazaporphyrin or
tetraazaporphyrin ring.
15. The method according to claim 14, wherein the near-infrared ray
absorbing material is used in an amount of 0.1 to 1 part by weight,
based on 100 parts by weight of the binder resin, and the
photoselective absorbing material is used in an amount of 0.1 to 1
part by weight, based on 100 parts by weight of the binder
resin.
16. The method according to claim 14, wherein the binder resin is
selected from the group consisting of natural polymers,
polymethylmethacrylate, polyvinylbutyral, polyvinylpyrrolidone,
polyvinyl alcohol, polyvinyl chloride, styrene-butadiene copolymer,
polystyrene, polycarbonate, and water-soluble polyamide.
17. The method according to claim 14, wherein the organic solvent
is selected from the group consisting of toluene, xylene, propyl
alcohol, isopropyl alcohol, methylcellosolve, ethylcellosolve,
dimethylformamide, methyl ethyl ketone, and butylacetate.
Description
[0001] This non-provisional application claims priority under 35
U.S.C. .sctn.119(a) on Korean Patent Application No. 2004-97642
filed on Nov. 25, 2004 which is herein incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Embodiments of the present invention relate to an optical
filter for image display devices and a method for manufacturing the
optical filter. More specifically, embodiments of the present
invention relate to an optical filter with superior color
reproduction and excellent shielding performance against infrared
rays, near-infrared rays and electromagnetic waves wherein a metal
pattern is directly formed on a transparent substrate and a
near-infrared ray shielding and photoselective absorbing layer is
formed thereon, and a method for manufacturing the optical
filter.
[0004] 2. Description of the Related Art
[0005] Various kinds of image display devices, including liquid
crystal displays (LCDs), plasma display panels (PDPs),
electroluminescent displays (ELDs), field emission displays, and
the like, are in practical use at present. Among these image
display devices, plasma display panels have received a great deal
of attention as large-size wall-mounted televisions and
large-screen multimedia displays.
[0006] The principle of light emission of plasma display panels is
as follows. First, an inert gas, such as helium, neon, argon and
xenon, is charged and sealed in barrier ribs. Thereafter,
application of a voltage ionizes the gas to form a plasma and emit
UV rays. The emitted UV rays excite phosphors to cause the
phosphors to emit light. In PDP displays, full-color display is
implemented by emitting red, blue and green primary phosphors. At
this time, excess fluorescence (500-620 nm wavelength) produced
from neon as a filled gas is added to the emitted light, making it
impossible to achieve perfect color reproduction. Furthermore,
near-infrared rays of 800-1,050 nm wavelength are also radiated
from PDPs, thus causing malfunction of devices using near-infrared
ray remote controllers, incidence of diseases harmful to human
eyes, and interference with adjacent devices. Under such
circumstances, extensive research is actively being undertaken to
shield harmful electromagnetic waves and near-infrared rays emitted
from image display devices.
[0007] To overcome the above-mentioned problems, for example,
Japanese Patent Laid-open No. Sho 61-188501 suggests a method
associated with the use of a filter which absorbs light of certain
wavelength range, and Japanese Patent Laid-open Nos. Hei
5-205643.quadrature.9-145918.quadrature.9-306366 and 10-26704
disclose techniques for introducing reflection-preventing functions
into a filter absorbing light of certain wavelength.
[0008] On the other hand, Japanese Patent Laid-open No. 2001-13317
teaches a filter for image display devices capable of improving the
color reproduction and contrast of image display devices, e.g.,
PDPs, and shielding harmful electromagnetic waves and infrared rays
emitted from the devices wherein a selective absorption filter
layer containing a dye and a polymer binder is formed on at least
one surface of a transparent support.
[0009] Korean Patent Laid-open No. 2001-26838 teaches a technique
for enhancing the color purity and contrast of a color display
device by shielding light reflected from the display device and
light corresponding to a color between the three primary colors
emitted from the display device wherein a photoselective absorption
composition comprising a carbocyanine derivative dye is applied to
the surface of the color display device or to a filter.
[0010] Since the above prior art techniques involve a process of
forming a metal thin film, which requires high vacuum/high
temperature conditions, or an exposure process for forming a fine
shape and a subsequent etching process to form a mesh pattern, the
overall procedure is complicated and considerable processing costs
are incurred. FIG. 1 is a cross-sectional view schematically
showing the structure of a conventional optical filter for image
display devices. As shown in FIG. 1, the optical filter comprises
an antireflective film 10 for blocking near-infrared rays and
cutting neon light, a selective absorbing layer 20, a near-infrared
ray shielding film 30, a glass substrate 40, an intermediate film
50 formed on the back surface of the glass substrate 40 to adhere
the glass substrate 40 to a mesh pattern 60, and a transparent film
70 for protecting the substrate from damage and turbidity during
etching, these layers being laminated in this order from the
bottom. According to this multilayer optical filter, it is
difficult to obtain thinner and lighter optical filter. Moreover,
the lamination processes between the respective layers are complex,
which causes problems of high manufacturing costs and reduced
yield.
OBJECTS AND SUMMARY
[0011] Embodiments of the present invention have been made in view
of the above problems of the prior art, and it is one object of
embodiments of the present invention to provide a low-cost optical
filter for image display devices, e.g., PDPs, that is capable of
improving the color reproduction and contrast of images of image
display devices and shielding harmful electromagnetic waves and
near-infrared rays radiated from the image display devices.
[0012] It is another object of embodiments of the present invention
to provide a method for manufacturing an optical filter for image
display devices by forming a metal pattern in a simple and
cost-effective manner and forming a near-infrared ray shielding and
photoselective absorbing layer thereon, without the necessity of a
sputtering process requiring high vacuum conditions, a
photopatterning process using a photosensitive resin or an etching
process, thereby simplifying the manufacturing procedure and
reducing manufacturing costs.
[0013] In accordance with an embodiment of the present invention
for achieving the above objects, there is provided an optical
filter for image display devices comprising a transparent
substrate, a photocatalytic film formed on the back surface of the
transparent substrate, a metal pattern formed by selectively
exposing the photocatalytic film to light and growing a metal
crystal thereon by plating, and a near-infrared ray shielding and
photoselective absorbing layer formed on the metal pattern.
[0014] In accordance with another embodiment of the present
invention, there is provided a method for manufacturing an optical
filter for image display devices comprising the steps of coating a
photocatalytic compound on a transparent substrate to form a
photocatalytic film (a first step), selectively exposing the
photocatalytic compound to light and growing a metal crystal
thereon by plating to form a metal pattern (a second step), and
coating a resin containing a near-infrared ray shielding material
and a photoselective absorbing material on the metal pattern to
form a near-infrared ray shielding and photoselective absorbing
layer (a third step).
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above and other objects, features and other advantages
of embodiments of the present invention will be more clearly
understood from the following detailed description taken in
conjunction with the accompanying drawings, in which:
[0016] FIG. 1 is a cross-sectional view schematically showing the
structure of a conventional optical filter for image display
devices;
[0017] FIG. 2 is a cross-sectional view schematically showing the
structure of an optical filter for image display devices according
to one embodiment of the present invention; and
[0018] FIG. 3 shows schematic views illustrating the procedure of a
method for manufacturing an optical filter for image display
devices according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Embodiments of the present invention will now be described
in more detail with reference to the accompanying drawings.
[0020] FIG. 2 is a cross-sectional view schematically showing the
structure of an optical filter for image display devices according
to one embodiment of the present invention. Referring to FIG. 2,
the optical filter for image display devices according to
embodiments of the present invention comprises a transparent
substrate 200, a photocatalytic film 300, a metal pattern 400, and
a near-infrared ray shielding and photoselective absorbing layer
500. The optical filter may also contain an antireflective film
100.
[0021] The near-infrared ray shielding and photoselective absorbing
layer 500 used in embodiments of the present invention may contain
a near-infrared ray shielding material and a photoselective
absorbing material. The near-infrared ray shielding material
preferably is able to selectively absorb light in the near-infrared
region and to transmit light in the visible region. Since the line
spectra in the near-infrared region emitted from PDPs in the
optical filter of embodiments of the present invention are
preferably absorbed by the near-infrared ray absorbing material,
there is no damage to the operation of a remote controller or an
optical communication device around the PDPs. There is no
particular restriction as to the kind of the near-infrared ray
absorbing material used in embodiments of the present invention,
but there may be used, for example, at least one material selected
from the group consisting of mixed dyes of a nickel complex and a
diammonium, compound dyes containing copper ions and zinc ions,
cyanine dyes, anthraquinone dyes, squarylium compounds, azomethine
compounds, oxonol compounds, azo compounds and benzylidene
compounds. It is desirable to add the near-infrared ray absorbing
material in an amount of 0.1 to 1 part by weight, based on 100
parts by weight of a binder resin to be added.
[0022] Preferred photoselective absorbing materials that may be
used in embodiments of the present invention are
octaphenyltetraazaporphyrin and tetraazaporphyrin derivative dyes
wherein one ligand selected from ammonia, water and halogen is
coordinately bonded to a central metal (M) atom of an
octaphenyltetraazaporphyrin or tetraazaporphyrin ring. The metal
(M) is at least one metal selected from the group consisting of
zinc, palladium, magnesium, manganese, cobalt, copper, ruthenium,
rhodium, iron, nickel, vanadium, tin and titanium, and plays a role
in cutting neon light. It is desirable to add the photoselective
absorbing material in an amount of 0.1 to 1 part by weight, based
on 100 parts by weight of a binder resin to be added.
[0023] The near-infrared ray shielding and photoselective absorbing
layer 500 may further contain a binder resin. Examples of preferred
binder resins include, but are not limited to, natural and
synthetic polymers, for example, polymethylmethacrylate,
polyvinylbutyral, polyvinylpyrrolidone, polyvinyl alcohol,
polyvinyl chloride, styrene-butadiene copolymer, polystyrene,
polycarbonate, and water-soluble polyamide.
[0024] The near-infrared ray shielding and photoselective absorbing
layer 500 preferably has a thickness of 1 .mu.m to 20 .mu.m, and
more preferably 2 .mu.m to 10 .mu.m.
[0025] Examples of the transparent substrate 200 used in
embodiments of the present invention preferably include, but are
not especially limited to, transparent plastic substrates and glass
substrates. As materials for the transparent plastic substrates,
there may be used acrylic resins, polyesters, polycarbonates,
polyethylenes, polyethersulfones, olefin-maleimide copolymers,
norbornene-based resins, and the like. In the case where excellent
heat resistance is required, olefin-maleimide copolymers and
norbornene-based resins are preferred. Otherwise, it is preferred
to use polyester films, acrylic resins, and the like.
[0026] An antireflective film 100 having reflection-preventing
properties may be formed in the optical filter of embodiments of
the present invention. The antireflective film 100 refracts
external light incident on a PDP screen, thus preventing
deterioration of image contrast and reducing visual fatigue due to
reflection of the external light. The antireflective film 100
preferably has a specular reflectance of 3.0% or less. Examples of
materials for the antireflective film 100 include, but are not
particularly limited to, silicon-based organic materials,
fluorine-based organic materials, indium tin oxide (ITO), ZnO,
Al-doped ZnO, TiO.sub.2, and ZrO.
[0027] The metal pattern 400 of the optical filter of embodiments
of the present invention serves to block leakage of electromagnetic
waves from PDPs. The metal pattern 400 may be formed by selectively
exposing the photocatalytic film 300 formed on the back surface of
the transparent substrate 300 to light and directly growing a metal
crystal thereon by plating. When the metal wiring is directly
formed on the transparent substrate, the adhesive force between the
substrate and the metal pattern is good.
[0028] The optical filter of embodiments of the present invention
may be applied to a variety of image display devices, such as
liquid crystal displays (LCDs), plasma display panels (PDPs), and
electroluminescent displays (ELDs). When the optical filter of
embodiments of the present invention is applied to plasma display
panels (PDPs) and front plates thereof, particularly advantageous
effects may be achieved.
[0029] Another embodiment of the present invention is directed to a
method for manufacturing an optical filter for image display
devices. According to the method of an embodiment of the present
invention, an optical filter for image display devices is
manufactured in accordance with the following procedure. First, a
photocatalytic compound is coated on the back surface of a
transparent substrate to form a photocatalytic film (a first step).
The photocatalytic film is selectively exposed to light to form a
latent pattern acting as a nucleus for crystal growth, and then the
latent pattern is subjected to plating to grow a metal crystal
thereon, thereby forming a metal pattern (a second step).
Thereafter, a resin containing a near-infrared ray shielding
material and a selective absorbing material is coated on the metal
pattern to form a near-infrared ray shielding and photoselective
absorbing layer (a third step). If necessary, an antireflective
film may be laminated on the front surface of the transparent
substrate.
[0030] According to the method of an embodiment of the present
invention, a monolayer or multilayer metal pattern may be formed in
a rapid and efficient way by simple photolithography, without the
need for metal sputtering requiring high vacuum and high
temperature conditions, exposure and etching processes.
Hereinafter, the method of an embodiment of the present invention
will be explained in more detail based on the respective steps.
1. First Step: Formation of Photocatalytic Film
[0031] FIG. 3 shows schematic views illustrating the procedure of a
method for manufacturing an optical filter for image display
devices according to one embodiment of the present invention.
Referring to FIG. 3, first, a photocatalytic compound is coated on
a glass substrate to form a photocatalytic film. The term
"photocatalytic compound" as used herein refers to a compound whose
characteristics are changed by light. For example, the
photocatalytic compound may be inactive when not exposed to light,
but its reactivity is accelerated (i.e. activated) upon exposure to
light, e.g., UV light. In addition, an inactive photocatalytic
compound may be electron-excited by photoreaction upon light
exposure, thus exhibiting a reducing ability. Preferred examples of
the photocatalytic compound are Ti-containing organometallic
compounds which may form TiO.sub.x after coating and annealing.
[0032] The coating thickness of a photocatalytic film is preferably
in the range of 30 nm to 1,000 nm. The photocatalytic compound may
be dissolved in an appropriate solvent to prepare a coating
solution, and then the coating solution may be coated on the
substrate. After coating, the resulting structure may be heated on
a hot plate or a microwave oven at a temperature preferably not
higher than 200.degree. C. for preferably not more than 20 minutes
to form a transparent photocatalytic compound layer.
[0033] Subsequently, a water-soluble polymer compound may be coated
on the photocatalytic compound layer (e.g., a Ti-containing organic
compound layer) to form the final photocatalytic film. The
water-soluble polymer layer thus formed plays a roll in promoting
photoreduction upon subsequent exposure to UV light, thus acting to
improve the photocatalytic activity. A photosensitizer may be added
to the aqueous water-soluble polymer solution to increase the
photosensitivity of the water-soluble polymer layer.
2. Second Step: Formation of Latent Pattern Acting as Nucleus for
Crystal Growth and Formation of Metal Pattern by Growth of Metal
Crystal
[0034] The photocatalytic film formed in the first step is
selectively exposed to light, e.g., UV light, using a photomask to
form a latent pattern acting as a nucleus for crystal growth
consisting of active and inactive portions. Exposure conditions
such as exposure atmospheres and exposure doses are not especially
limited, and may be properly selected according to the kind of
photocatalytic compounds used. In this step, two or more metals may
be grown to form a multilayer metal pattern.
[0035] As mentioned above, when the preferred photocatalytic film
is exposed to UV light, electron excitation occurs in the exposed
portion, thus exhibiting activity, e.g., reducibility, and as a
result, reduction of metal ions takes place in the exposed portion.
In this step, if necessary, the latent pattern acting as a nucleus
for crystal growth may be dipped in an appropriate metal salt
solution to form a metal particle-deposited pattern thereon and to
completely remove the water-soluble polymer layer, in order to
effectively form a metal pattern in the subsequent plating step.
The deposited metal particles play a role as catalysts accelerating
growth of a metal crystal in the subsequent plating step. For
example, when the pattern is plated with copper, nickel or gold,
treatment with the metal salt solution is preferred. As the metal
salt solution, an Ag salt solution, a Pd salt solution or a mixed
solution thereof is preferably used.
[0036] The latent pattern acting as a nucleus for crystal growth,
or if desired, the metal particle-deposited pattern, is subjected
to plating to grow a metal crystal thereon to form a metal pattern.
The plating may be performed by electroless or electro-plating.
[0037] In the case of the metal particle-deposited pattern formed
by treating the latent pattern with a metal salt solution crystal
growth may be accelerated and thus a more densely packed metal
pattern may be advantageously formed.
[0038] Plating metals, e.g., Cu, Ni, Ag, Au, Co and alloys thereof,
usable for the plating in embodiments of the present invention may
be properly selected. To form a highly conductive metal pattern, a
copper or silver compound solution is preferably used. The
electroless or electroplating may be achieved in accordance with
well-known procedures.
3. Formation of Near-Infrared Ray Shielding and Photoselective
Absorbing Layer
[0039] A near-infrared ray shielding and photoselective absorbing
layer is formed by mixing a near-infrared ray absorbing material, a
photoselective absorbing material and a binder resin in an organic
solvent to prepare a coating solution, coating the coating solution
to a predetermined thickness on the metal pattern formed on the
transparent substrate, and curing the coating solution. In this
step, the coating may be conducted by general coating techniques
such as spin coating, roll coating, die coating, spray coating, and
the like.
[0040] The near-infrared ray shielding and photoselective absorbing
layer preferably has a thickness of 1-20 .mu.m, and more preferably
2-10 .mu.m.
[0041] As the binder resin, there may be used poly(methyl
methacrylate), polyvinyl alcohol, polycarbonate,
ethylenevinylacetate, poly(vinylbutyral), or the like. The binder
resin is preferably used in an amount of 2-50 parts by weight,
based on 100 parts by weight of the organic solvent.
[0042] Examples of the organic solvent include, but are not
particularly limited to, toluene, xylene, propyl alcohol, isopropyl
alcohol, methylcellosolve, ethylcellosolve, dimethylformamide,
methyl ethyl ketone, and butylacetate.
[0043] The near-infrared ray shielding and photoselective absorbing
layer 500 may further contain other additives for control of the
transmittance in each wavelength range and fine color control. As
such additives, there may be used common azo dyes, cyanine dyes,
diphenylmethane dyes, triphenylmethane dyes, phthalocyanine dyes,
xanthene dyes, diphenylene dyes, indigo, and porphyrin dyes.
EXAMPLES
[0044] Embodiments of the present invention will now be described
in more detail with reference to the following examples. However,
these examples are given for the illustration of preferred
embodiments of the present invention only, and are not to be
construed as limiting the scope of the invention.
Examples 1 to 3
[0045] A solution of polybutyl titanate (2.5 wt %) in isopropanol
was applied to a transparent glass substrate by spin coating, and
was then dried at 150.degree. C. for 5 minutes to form an amorphous
TiO.sub.2 film having a thickness of 30 mm to 100 nm. Thereafter,
triethanol amine as a photosensitizer was added to an aqueous
solution of 5 wt % of polyvinylalcohol (Mw: 25,000). At this time,
the photosensitizer was used in an amount of 1% by weight, based on
the weight of the polymer. The resulting mixture was stirred,
coated on the TiO.sub.2 film, and dried at 60.degree. C. for 2
minutes. Next, UV light having a broad wavelength range was
irradiated to the coated substrate through a photomask on which a
fine mesh pattern was formed using a UV exposure system (Oriel,
U.S.A). After the exposure, the substrate was dipped in a solution
of PdCl.sub.2 (0.6 g) and KCl (1 ml) in water (1 liter) to deposit
Pd particles on the surface of the exposed portion. As a result, a
negative pattern composed of Pd, acting as a nucleus for crystal
growth, was formed.
[0046] The resulting substrate was dipped in an electroless copper
plating solution to selectively grow a crystal of a metal pattern.
The copper plating solution used herein was prepared so as to have
a composition comprising 3.5 g of copper sulfate, 8.5 g of Rochelle
salt, 22 ml of formalin (37%) as a reducing agent, 1 g of thiourea
as a stabilizer, 40 g of ammonia as a complexing agent, and one
liter of water. While maintaining the temperature of the copper
plating solution at 35.degree. C., the dipped substrate was
subjected to electroless plating for 5 minutes to form a copper
mesh pattern having a thickness of 2 .mu.m and a line width of 10
.mu.m. The mesh pattern was measured to have a sheet resistance of
0.01 .OMEGA./sq. or lower.
[0047] To impart electromagnetic waves shielding, color
compensation and near-infrared ray shielding functions, a cyanine
dye (TY Series.sup.R, light absorption at 580-600 nm wavelength
range, Asahi Denka, Japan), a nickel dithiol dye (NKY119.sup.R,
light absorption at 800-900 nm wavelength range, Hayashibara,
Japan), a diammonium type dye (CIR 1081.sup.R, absorption of
near-infrared rays, Japan Carlit), and an Orasol series dye as an
organic dye for fine color control (Ciba Special Chemical) were
mixed in the same amounts, and then 6 kg of a butyl acetate
solution containing 1 kg of an acrylic polymer was added thereto.
The mixture was stirred for about 2 hours to prepare a coating
solution. The coating solution was applied to a thickness of 20
.mu.m to the pattern, and dried at 100.degree. C. for 10 minutes to
a thickness of 5 .mu.m. An antireflective film was attached to the
surface opposed to the substrate to fabricate an optical filter of
embodiments of the present invention.
[0048] Each of the optical filters manufactured in Examples 1-3 was
mounted on a PDP. Neon cut performance and visible transmittance
were measured before and after mounting on the PDP using a
spectrometer, and the obtained results are shown in Table 1 below.
TABLE-US-00001 TABLE 1 Cyanine dye Neon light Example (light
emission at Visible ray Electrical shielding No. 580-600 nm
transmittance conductivity performance Example 1 3 g 60%
.ltoreq.0.01 .OMEGA./sg. Good Example 2 5 g 30% .ltoreq.0.01
.OMEGA./sq. Good Example 3 7 g 20% .ltoreq.0.01 .OMEGA./sq.
Excellent
[0049] As can be seen from the data shown in Table 1, optical
filters of embodiments of the present invention exhibit excellent
near-infrared ray shielding and neon light cutting effects and
improved visible ray transmittance.
[0050] As apparent from the foregoing, according to the method of
an embodiment of the present invention, a metal pattern may be
formed by forming a photocatalytic compound using a simple coating
technique, followed by simple plating. Accordingly, an optical
filter for image display devices may be manufactured within a short
time at low costs without the need for a sputtering process
requiring high vacuum/high temperature conditions or a
photopatterning process using a photosensitive resin or an etching
process. In addition, an optical filter of embodiments of the
present invention exhibits improved visibility due to superior
color reproduction and reduced surface reflection, and may cut off
unnecessary infrared rays and electromagnetic waves radiated from
display devices. Furthermore, according to a method of an
embodiment of the present invention, an unnecessary adhesive layer
may be removed. Moreover, according to a method of an embodiment of
the present invention, since a near-infrared ray shielding layer
and a photoselective absorbing layer are combined, the structure of
the optical filter is simplified, thus contributing to the
reduction in weight and manufacturing costs of the optical
filter.
[0051] Although preferred embodiments of the present invention have
been disclosed for illustrative purposes, those skilled in the art
will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
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