Title: Substrate and organic electroluminescence device using the substrate
Abstract: A substrate and an organic electroluminescence device employing the substrate are provided. The substrate has at least one non-continuous photo-resist coating layer formed on at least one surface of a supporting substrate and the non-continuous photo-resist coating has a plurality of continuous portions. The continuous portions may have high surface energy areas and low surface energy areas. A second photo-resist coating layer is used to at least temporarily overlap the continuous portion which corresponds to the high surface energy area in order to form the low surface energy area.
Patent Number: 7,015,501 Issued on 03/21/2006 to Redecker, et al.
| Inventors:
|
Redecker; Michael (Berlin, DE);
Schaedig; Marcus (Berlin, DE);
Kubiak; Michael (Berlin, DE)
|
| Assignee:
|
Samsung SDI Co., Ltd. (Suwon, KR)
|
| Appl. No.:
|
627683 |
| Filed:
|
July 28, 2003 |
Foreign Application Priority Data
| Aug 02, 2002[DE] | 102 36 404 |
| Mar 13, 2003[KR] | 10-2003-0015598 |
| Current U.S. Class: |
257/40; 257/E51.022; 257/643; 257/791; 257/792; 313/504 |
| Current Intern'l Class: |
H01L 35/24 (20060101) |
| Field of Search: |
257/40,676,642,643,791,792,794,E25.032,E51.022,E21.007,E21.024,E21.254, E21.299,E23.018
313/504
|
References Cited [Referenced By]
U.S. Patent Documents
| 2003/0148024 | Aug., 2003 | Kodas et al.
| |
| 2003/0171060 | Sep., 2003 | Hirano et al.
| |
| 2004/0009673 | Jan., 2004 | Sreenivasan et al.
| |
| 2004/0175646 | Sep., 2004 | Hatanaka et al.
| |
Primary Examiner: Flynn; Nathan J.
Assistant Examiner: Wilson; Scott R.
Attorney, Agent or Firm: H.C. Park & Associates, PLC
Claims
What is claimed is:
1. A substrate having a non-continuous photo-resist coating layer, an insulating
layer and a pixel defining layer formed on at least one surface of a supporting
substrate, wherein the non-continuous photo-resist coating layer, insulating layer
and pixel defining layer comprises a plurality of continuous portions, and the
plurality of continuous portions comprise:
at least one high surface energy area; and
at least one low surface energy area, wherein at least one of a second photo-resist
coating layer and a mask is used to at least temporarily overlap the continuous
portion corresponding to the at least one high surface energy area in order to
form the at least one low surface energy area.
2. The substrate of claim 1, wherein the high surface energy areas have a surface
energy of about 60-70 dyne/cm and the low surface energy areas have a surface energy
of about 20-35 dyne/cm.
3. The substrate of claim 1, wherein the supporting substrate is rigid.
4. The substrate of claim 1, wherein the supporting substrate is flexible.
5. The substrate of claim 1, wherein the supporting substrate is made of at least
one of glass, plastic and silicon.
6. The substrate of claim 1, wherein the non-continuous photo-resist coating
material is at least one of a Novolak based photo-resist, acrylic lacquer, epoxy
lacquer and polyimide lacquer.
7. An organic electroluminescence device, comprising:
a pixel defining layer (PDL) patterned to expose an active pixel surface portion
of a substrate on which the PDL is formed,
wherein the PDL includes a high surface energy area and a low surface energy
area, the high surface energy area being disposed between the active pixel surface
portion and the low surface energy area to prevent a decay of a coating thickness
in a boundary zone of the active pixel surface portion.
8. The organic electroluminescence device according to claim 7, wherein a surface
energy of the active pixel surface portion is high.
9. The organic electroluminescence device according to claim 7, wherein at least
one layer is provided on the PDL, and a surface of the layer includes at least
one area with a high surface energy and at least one area with a low surface energy.
10. The organic electroluminescence device according to claim 7, wherein the
PDL is a photo-resist coating layer.
11. The organic electroluminescence device according to claim 7, further comprising:
a homogeneous pattern of polymer film formed over the active pixel surface portion
and the high surface energy portions of the PDL.
12. The organic electroluminescence device according to claim 11, wherein the
polymer film comprises a light-emitting semi-conducting polymer (LEP).
Description
This application claims the benefit of German Patent Application No. 102 36
404.4 filed on Aug. 2, 2002 and Korean Patent Application No. 10-2003-0015598,
filed on Mar. 13, 2003, which are hereby incorporated by reference for all purposes
as if fully set forth herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a substrate and an organic electroluminescence device
using the substrate, and more particularly, to a substrate with a plurality of
surface energies which can be manufactured at low cost and with a thinner coating
than conventional substrates, and an organic electroluminescence device using the substrate.
2. Description of the Related Art
An inkjet printing process is an important structuring process for the manufacture
of full-color displays using light-emitting polymers (LEPs). In the inkjet printing
process, a small amount of a polymer solution is deposited onto a suitable substrate.
The spatial dissolution of the polymer solution is predominantly influenced by
the surface characteristics of the substrate. To avoid color mixing of the so called
"pixel surface", wetting using deposited polymer ink should be carried out only
in a zone which is envisioned for a light-emitting pixel.
Areas of a substrate surface with a high surface energy allow ink for printing
to flow, whereas areas with a low surface energy act as a barrier to ink flow.
To obtain a film having a homogenous coating thickness, it is advantageous for
a portion of the substrate beyond a boundary of a pixel surface of an organic light-emitting
diode (OLED) to have a high surface energy. If the portion of the substrate beyond
the boundary of the pixel surface has a high surface energy, the formed film has
a homogenous thickness up to the boundary and the coating thickness noticeably
declines outside an active zone in the vicinity of the barrier.
A desired contrast in surface energy can be achieved in different ways and by
different methods.
One known approach is described in the EP 0989778 A1. In this approach, a substrate
surface with a contrast of surface energies is formed by means of a suitable selection
of materials for forming the substrate surface.
EP 0989778 A1, for example, describes a two-coating structure of a surface. By
means of a suitable plasma surface treatment, an upper coating can be provided
with a low surface energy while a lower coating, because of its chemical nature,
receives a high surface energy with the same treatment. The lower coating is typically
manufactured from inorganic materials such as silicon oxide/nitride.
In this approach, the inorganic coating acts as a boundary zone with a high surface
energy and facilitates the deposition of homogenous polymer films by means of inkjet
printing. However, for deposition and structuring of inorganic coatings, various
processes typically used in the semi-conductor industry should be performed. For
example, to attain the inorganic coatings, separation, sputter processes and gas
phase processes such as PECVD (Plasma Enhanced Chemical Vapor Deposition) may be used.
However, these processes are expensive, and thus reduce the cost efficiency
that can be gained by using OLED technology. Moreover, the second coating layer
has a surface topography such that the areas with low surface energy (hereinafter
called "separators") are spaced apart a predetermined height from the substrate
surface. As a result of this height profile, the separated polymer film can form
an undesirable thickness profile.
JP09203803, for example, describes a chemical treatment on a substrate
surface having a photo-resist formed thereon. The photo-resist is exposed using
a mask and then developed. In the resulting structure, the areas with the photo-resist
have a low surface energy while areas without the photo-resist have a high surface
energy. The flanks of the photo-resist structure have a mean surface energy, and
thus can avoid an abrupt transition in surface energy to a certain degree. However,
the flanks do not represent a boundary zone with a freely selectable surface energy
and geometry because the spatial dissolution capacity of the inkjet printing process
disadvantageously declines through areas with a mean surface energy.
JP09230129, for example, describes a two-stage treatment on a substrate
surface. Initially, the substrate surface has a low surface energy, but the surface
energy gradually increases at a predetermined portion of the surface which is treated
with short-wavelength light. However, according to this method, contrast of a surface
energy is limited and an exposure time is prolonged, making mass production difficult.
SUMMARY OF THE INVENTION
The present invention provides, for example, a substrate with a coating which
is thinner than conventional coatings and with a good spatial dissolution capacity
for ink-jet printing, which can be manufactured at low cost, a manufacturing method
of the substrate, an organic electroluminescence device using the substrate and
a manufacturing method of the organic electroluminescence device. The substrate
according to this invention has a plurality of comparatively different surface
energies, such as, for example, at least one region with a low surface energy and
at least one region with a comparatively high surface energy.
This invention provides a method for manufacturing a substrate by depositing
a first photo-resist coating material on a supporting substrate, exposing the first
photo-resist coating material using a mask, developing the first photo-resist coating
material to provide a first photo-resist coating layer; treating with a first treatment
the first photo-resist coating layer to adjust a surface energy of the first photo-resist
coating layer, depositing a second photo-resist coating material on at least a
portion of the first photo-resist coating layer, exposing the second photo-resist
coating material using a mask, developing the second photo-resist coating material
to provide a second photo-resist coating layer, wherein at least a portion of the
second photo-resist coating layer overlaps at least a portion of the first photo-resist
coating layer, treating with a second treatment at least one portion of the first
photo-resist coating layer, and removing the second photo-resist coating layer.
In various exemplary embodiments of the devices and methods according to this
invention, the first photo-resist coating layer may be provided with a high surface
energy by using, for example, an UV-ozone treatment or an oxygen-plasma treatment.
The surface energy of at least a portion of a surface may be reduced in the various
exemplary embodiments according to this invention by using a plasma treatment which
includes, for example, a fluorine-containing gas mixture where the fluorine-containing
gas mixture is, for example, at least one of CF
4, SF
6 and NF
3.
This invention separately provides reducing the surface energy of a surface
using a plasma treatment which includes a gas mixture of tetrafluoromethane and
oxygen in the volume ratio 4:1.
In various exemplary embodiments of the devices and methods according to this
invention, the first photo-resist coating material and the second photo-resist
coating material are at least one of a Novolak based photo-resist on, acrylic lacquer,
epoxy lacquer and polyimide lacquer.
In various exemplary embodiments of the devices and methods and according to
this
invention, the second photo-resist coating is removed by using, for example, at
least one of acetone and tetrahydrofuran.
This invention separately provides a substrate having at least one non-continuous
photo-resist coating layer formed on at least one surface of a supporting substrate,
wherein the at least one non-continuous photo-resist coating layer comprises a
plurality of continuous portions, and the plurality of continuous portions comprise
at least one high surface energy area, and at least one low surface energy area,
wherein a second photo-resist coating layer is used to at least temporarily overlap
the continuous portion corresponding to the at least one high surface energy area
in order to form the at least one low surface energy area.
This invention provides a substrate which has at least one high surface energy
area and at least one low surface energy area where the surface energy of the high
surface energy is about 60-70 dyne/cm and the surface energy of the low surface
energy area is about 20-35 dyne/cm.
This invention provides a substrate having a supporting substrate which may
be rigid or flexible.
This invention provides a substrate having a supporting substrate which is made,
for example, of glass, plastic or silicon.
This invention provides a substrate having a photo-resist coating material which
is at least one selected from the group consisting of a Novolak based photo-resist,
acrylic lacquer, epoxy lacquer and polyimide lacquer.
This invention separately provides a method of manufacturing an organic electroluminescence
device comprising depositing a first photo-resist coating material on a supporting
substrate, exposing and developing the first photo-resist coating material to provide
a first photo-resist coating layer, treating with a first treatment at least one
surface of the first photo-resist coating layer to adjust a surface energy of the
first photo-resist coating layer, depositing a second photo-resist coating material
on at least a portion of the first photo-resist coating layer, exposing and developing
the second photo-resist coating material to provide a second photo-resist coating
layer, wherein at least a portion of the second photo-resist coating layer overlaps
at least a portion of the first photo-resist coating layer, treating with a second
treatment at least one portion of the first photo-resist coating layer not overlapped
by the second photo-resist layer, removing the second photo-resist coating layer,
and supplying an ink drop containing an organic layer forming material to the resultant
structure to form an organic layer.
This invention separately provides a method for manufacturing an organic electroluminescence
device in which the organic layer forming material is at least one selected from
the group consisting of a conductive polymer and a light-emitting polymer. In the
various exemplary embodiments of this invention, the conductive polymer is at least
one of polyethylene dioxothiophene—polystyrene sulfone acid, polyaniline
and a mixture thereof.
This invention separately provides a method for manufacturing an organic electroluminescence
device in which the surface tension of the conductive polymer is reduced using
at least one of a surfactant and a lower alcohol. The lower alcohol may be, for
example, one of butanol and propanol.
This invention separately provides a method for manufacturing an organic electroluminescence
device in which the organic layer is a light-emitting portion.
This invention separately provides a method for manufacturing an organic electroluminescence
device manufactured by the method according to the present invention. The organic
layer is formed, for example, by imprinting at least one of a conductive polymer
and a solution of a light-emitting polymer using inkjet printing.
This invention separately provides an organic electroluminescence device, comprising
a pixel define layer (PDL), wherein the PDL defines at least one area of the organic
electroluminescence device with a high surface energy and at least one area of
the organic electroluminescence device with a low surface energy. This invention
separately provides a method for manufacturing a substrate, comprising depositing
at least one of a first insulating layer and a first pixel defining layer on a
supporting substrate, and treating at least a first portion of at least one of
the first insulating layer and the first pixel defining layer, and treating a second
portion of the first portion of at least one of the first insulating layer and
the first pixel defining layer. These and other features and advantages of this
invention are described in, or are apparent from, the following detailed description
of various exemplary embodiments of the systems and methods according to this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Various features and advantages of the present invention will be described
with reference to the following figures.
FIG. 1 is a diagram of a non-treated substrate surface.
FIG. 2 shows a substrate surface having a first photo-resist coating layer.
FIG. 3 shows a substrate surface having a first coating layer, a second coating
layer and a partially overlaid photo-resist coating layer (each exposed and developed).
FIG. 4 shows a substrate surface subjected to a treatment for reducing a surface
energy and a treatment for removing the second photo-resist coating layer.
FIG. 5 shows a treated substrate surface with an ink drop above the same.
FIG. 6 is a top view of a substrate for an organic light-emitting element with
an already applied ink drop.
FIG. 7 shows a laminated structure of an organic electroluminescence device
according to an embodiment of this invention.
DETAILED DESCRIPTION OF THE INVENTION
This invention provides a method for manufacturing a substrate having a single
coating and a plurality of surface energies which can be manufactured using commercially
available materials and with cost-saving methods.
A first photo-resist coating material is deposited onto a supporting substrate
to form a first photo-resist coating layer. The first photo-resist coating material
may, for example, be a commercially available photo-resist, such as, for example
a Novolak based photo-resist, acrylic lacquer, epoxy lacquer or polyimide lacquer.
The photo-resist coating layer is exposed with a photo mask and then developed.
The first coating layer is thermally cross-linked and surface treated such that
at least a portion of the first coating layer has a high surface energy. The surface
treatment may be, for example, an UV-ozone treatment or an oxygen plasma treatment.
Thereafter, a second photo-resist coating layer is formed. The second
photo-resist coating layer may be, for example, a commercially available photo-resist.
The second photo-resist coating layer is exposed with a photo mask and then developed.
The second photo-resist coating layer overlaps at least a portion of the first
photo-resist coating layer. The surface of the substrate is treated such that the
surface energy of the substrate surface is lowered. For example, the surface energy
of the exposed first photo-resist coating layer (i.e., the portion of the first
photo-resist coating layer which is not overlapped with the second photo-resist
coating layer) and the surface energy of the second photo-resist coating layer
are lowered. To lower the surface energy of the substrate, the substrate surface
is treated, for example, with a fluorine gas mixture such as, for example, CF
4,
SF
6 or NF
3.
The surface energy can also be lowered by a plasma treatment using, for example,
a gas mixture of tetrafluoromethane and oxygen mixed in a volume ratio of 4:1.
The second photo-resist coating layer is then removed. The second photo-resist
coating layer may be removed with, for example, an organic solvent such as acetone,
tetrahydrofuran or the mixtures thereof. By suitably selecting photo masks and
surface treatments, a first photo-resist coating layer can be made to have a desired
geometry and a desired contrast of surface energies.
Thus, according to the features of this invention, a substrate with a plurality
of surface energies can be manufactured that has a single coating. Although a second
coating layer is used to manufacture the substrate, the second coating layer may
be removed such that the formed substrate has a single coating layer. Thus, a substrate
with a high-contrast energy and with only one coating may be manufactured according
to the features of this invention. According to the features of this invention,
it is possible to only use organic materials for coating build-up. According to
this method, a high contrast in surface energy can be obtained with a low coating thickness.
A supporting substrate can be made, for example, of glass, plastic, silicon or
other flexible or rigid materials. The coating layer may consist, for example,
of a photo-resist which is exposed using a photo mask and then developed. In this
case, a commercially available photo-resist can be used as the photoresist. As
discussed above, structuring of a polymer layer can be made by etching the polymer
layer using a photo-resist mask. The surface energy can be lowered, for example,
by means of a suitable UV-ozone or oxygen plasma treatment, respectively.
The substrate according to the invention can be used, for example, for forming
organic layers of an organic electroluminescence device. Materials for forming
such organic layers are not particularly limited, but preferred examples thereof
include conductive polymer, light-emitting materials, such as, for example, light-emitting
polymers, and mixtures thereof. The substrate according to the invention can be
used, for example, for imprinting a conductive polymer and/or for imprinting a
solution of light-emitting polymers by means of an inkjet printing system.
The conductive polymer may comprise, for example, polyethylene dioxothiophene-polystyrene
sulfone acid (PEDT-PSS), polyaniline or a mixture thereof. A surface tension of
the conductive polymer can be reduced by means of suitable additives, such as,
for example, a surfactant or a lower alcohol, such as, for example, butanol or
propanol. The polymer coating separated in this way is dried by a thermal treatment.
The light-emitting polymers may be derived, for example, from polyphenylenvinylenes
(PPVs) or polyfluorenes or a mixture thereof.
In an inkjet printing process to be described later, the first step is imprinting
of a solution containing a suitable conductive polymer. The coating of the conductive
polymer serves to improve injection of defect electrons (holes) into a light-emitting
material. The coating layer also planarizes an anode coating layer (indium-tin-oxide),
thereby preventing the life of an OLED from being shortened due to unevenness.
Solutions of light-emitting polymers, such as, for example, solutions from
the polyphenylenvinylenes (PPVs) and the polyfluorenes (PFOs), are imprinted by
an inkjet printing
5 method. Thereafter, deposition of a metallic cathode
coating layer is performed by means of vacuum evaporation/sputtering, followed
by encapsulation.
As shown in FIG. 1, a rigid or flexible supporting substrate
1 made of
glass, silicon or another material is used. A light-emitting polymer (LEP) is to
be imprinted later onto a certain area
2, a so-called active pixel surface.
To avoid color mixing, which is the mixing of polymers of different colors and
to be able to individually activate the polymers for the purpose of producing a
picture a polymer should be deposited on a predetermined portion of the substrate
1.
A first photo-resist coating material is applied onto the supporting substrate
1 by spin-coating. The applied first photo-resist coating material is exposed
using a photo mask. The applied and exposed first photo-resist coating material
is then developed, thermally treated, and UV-ozone and/or an oxygen-plasma treated.
The treated substrate is shown in FIG. 2. A photo-resist coating layer
3
with a high surface energy is formed by the UV-ozone and/or the oxygen-plasma treatment.
Then, as shown in FIG. 3, a second photo-resist coating material is applied
onto the resultant structure by spin-coating, followed by exposure and development
using a photo mask, thereby forming a second photo-resist coating layer
4.
The second photo-resist coating layer overlaps boundary zones of the first photo-resist
coating layer
3. Next, the substrate
1 is subjected to a plasma treatment
with a fluorine-containing gas mixture. In particular, CF
4, SF
6
and NF
3 are appropriate fluorine gases. As a result, a particular part
of the first photo-resist coating layer
3, which is not covered by the second
photo-resist coating layer
4, is provided with a low surface energy. However,
a part of the first coating
3, overlaid by the second coating
4,
retains its comparatively high surface energy.
The second photo-resist coating layer
4 is removed by a suitable solvent
such as acetone, tetrahydrofuran or the mixtures thereof. A surface of the resulting
substrate is shown in FIG. 4, showing a partial photo-resist coating layer with
areas of a high surface energy, that is, the particular part of the first photo-resist
coating
3, and areas of a low surface energy, that is, portions indicated
by reference numeral
5. The geometry of these areas can be arranged at random
by means of a suitable selection of a photo mask. The ratio of a surface energy
of the areas
3 to that of the areas
5 can also be advantageously
arranged by means of a suitable UV-ozone and/or oxygen-plasma treatment.
FIG. 5 shows a photo-resist coating treated with an ink drop
6 disposed
above the photo-resist coating and made of a light-emitting semi-conducting polymer
(LEP). The ink drop flows in an area of the active pixel surface
2 and in
boundary zones of the photo-resist coating
3 with high surface energy.
As the surface energy transitions from a high state to a low state outside the
active pixel surface
2, a substantially uniform coating thickness is ensured
over the active pixel surface
2. A substantially uniform coating is ensured
because a decay of the coating thickness in the boundary zones of the active pixel
surface
2 will not take place as this decay will only occur in the vicinity
of the areas
5 with a low surface energy. In this way, a homogeneous pattern
of the polymer film is ensured.
FIG. 6 is a top view of a substrate for an organic light-emitting element after
inkjet printing. Here, the active pixel surface
2 and the areas of the photo-resist
coating
3 with a high surface energy are wetted with ink. In contrast, the
area
5 with a low surface energy is not wetted by ink.
In an exemplary embodiment of a method for forming a substrate according the
this
invention, glass with a pre-structured indium-tin-oxide coating, for example, is
used as a supporting substrate. A first photo-resist coating material, such as,
for example, a Novolak based photo-resist, e.g., JEM 750 of Messrs JSR (Japan Synthetic
Rubber), is applied, for example, by spin-coating to a thickness of about 500 nm,
and then exposed using a suitable photo mask. After development, the resulting
structure is thermally treated at about 200° C. for about one hour.
Subsequently, the thermally treated resulting structure is treated
in oxygen plasma, for example, for about 120 seconds, thereby forming a first photo-resist
coating layer. Thereafter, a second photo-resist coating material is applied onto
the resulting structure by spin-coating. The second photo-resist coating material
may, for example, be a Novolak based photo-resist, e.g., AZ6612 of Messrs Clariant.
The resulting structure is exposed using a suitable photo mask and developed.
The resulting substrate, in this exemplary embodiment, is subjected to an oxygen
plasma treatment for subsequent treatment. For example, the resulting substrate
is plasma treated using, for example, a gas mixture of tetrafluorine methane-oxygen
in the volume ratio of about 4:1 for about 120 seconds. The second photo-resist
coating layer is removed, preferably immediately after the plasma treatment, by
a suitable solvent, such as, for example, acetone, tetrahydrofuran or the mixtures thereof.
In this exemplary embodiment, the area
5 with the low surface energy,
which
acts as a separator zone is, for example, preferably approximately 10-20 μm
wide. An interim space in the active pixel area
2 is, for example, approximately
30 μm, which corresponds to a resolution of approximately 130 PPI. The surface
energy of the area
3 with a high surface energy is, for example, approximately
60-70 dyne/cm, while the surface energy of the area with a low surface energy is,
for example, approximately 20-35 dyne/cm.
FIG. 7 shows a laminated structure of an active matrix type organic electroluminescence
device according to an embodiment of the present invention. As shown in FIG. 7,
a buffer layer
111 made of SiO
2 is formed on an insulating substrate
11, and a TFT
23 and an EL device
24 are provided on the buffer
layer
111.
The TFT
23 includes a semiconductor active layer
231 made of, for
example, amorphous silicon or polycrystalline silicon formed on the buffer layer
111. The semiconductor active layer
231 has a source region and a
drain region, which are doped with high-concentration N-type or P-type impurities.
A gate insulating layer
112 is provided on the semiconductor active layer
231 and a gate electrode
232 is provided on the insulating layer
112. The gate electrode
232 is connected to an electrode (not shown)
of a capacitor (not shown) to supply a TFT on/off signal. A source electrode
233
is connected to a drive line
25 and supplies a reference voltage to the
semiconductor active layer
231. A drain electrode
234 connects the
TFT
23 with the EL device
24 and applies a drive power to the EL
device
24. An interlayer insulating film
113 is provided between
each of the gate electrode
232, the source electrode
233 and the
drain electrode
234. A passivation film
114 is interposed between
the source electrode
233 and drain electrode
234 and an anode electrode
241, which is an electrode of the EL device
24.
A pixel define layer (PDL)
115 made of acryl, for example, is formed on
the anode electrode
241, and a predetermined opening
244 is formed
in the PDL
115. Neighboring pixels are spaced apart from each other by the
PDL
115, thereby defining a pixel area. The PDL
115 corresponds to
an interlayer insulating film formed between anodes in a passive matrix type organic
EL device.
Reference numeral
75 in FIG. 7 denotes a low surface energy area
of the PDL
115. The low surface energy area
75 corresponds to the
area represented by reference numeral
5 in FIG. 6. The remaining portion
of the PDL
115 (i.e., the area not represented by reference numeral
75)
denotes a high-energy area.
Areas with a high surface energy and areas with a low surface energy are defined
by the PDL
115. The surface energy of an area where the PDL
115 is
not formed may be either high or low. As shown in FIG. 7, at least one layer is
further laminated on the PDL
115, and areas with a high surface energy and
areas with a low surface energy may be provided on the surface of the layer. The
PDL
115 may be, for example, a photo-resist coating layer. The same surface
treatment as that for the photo-resist coating layer is applied to the PDL
115
and the layer formed on the PDL
115.
As shown in FIG. 7, a portion of the PDL
115 can be a low surface energy
area
75. The remainder of the PDL
115 may be a high surface energy area.
The EL device
24 displays a predetermined image by emitting red, green
or blue light according to the flow of current. The EL device
24 includes
an anode electrode
241, a cathode electrode
243 and an organic emitting
layer
242. The anode electrode
241 is connected to the drain electrode
234 of the TFT
23 and receives positive power from the drain electrode
234. The cathode electrode
243 covers the pixels and supplies negative
power thereto. The organic emitting layer
242 is disposed between the anode
electrode
241 and the cathode electrode
243 and it emits light.
The anode electrode
241 may be, for example, a transparent electrode made
of ITO. In the case of a rear-surface emission type in which the device
24
emits light toward the substrate
11, the cathode electrode
243 is
formed through blanket-deposition of Al/Ca, for example. In the case of a front-surface
emission type in which the device
24 emits light toward a sealing member
12 opposite to and facing the substrate
11, the cathode electrode
243 is formed of a transparent material such that a thin-semi-transparent
film made of Mg/Ag, for example, is formed and transparent ITO is then deposited
thereon. The cathode electrode
243 may be formed through blanket-deposition,
however, it may also be formed, for example, in various patterns. It should be
understood that the anode
241 and the cathode
243 may be laminated
in the opposite order. The organic layer
242 may be, for example, a low-molecular
weight organic layer or a polymeric organic layer.
The substrate according to this invention may be manufactured at low cost and
with a good contrast in surface energy (i.e., for example, a substrate with a plurality
of surface energies including a high surface energy and a comparatively low surface
energy) and with a reduced coating thickness, compared to conventional substrates.
The substrate may be used, for example, for imprinting a conductive polymer and/or
for imprinting a solution of light-emitting polymers by means of an inkjet printing system.
In the above description of various exemplary embodiments according to the present
invention, the first photo-resist coating material is treated to have a high surface
energy area and the second photo-resist coating material is treated to have a low
surface energy area. However, it should be appreciated that it is possible, for
example, to treat the first photo-resist coating material to have a low surface
energy area and to treat the second photo-resist coating material to have a high
surface energy in accordance with the features of this invention.
The invention is not limited to the embodiments presented and illustrated here.
Moreover, it is possible to realize further embodiment variants by means of combination
and modification of the stated means and features, without departing from the framework
of the invention.
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