U.S. patent application number 11/158011 was filed with the patent office on 2005-12-29 for electro-luminescent device and method for manufacturing the same.
This patent application is currently assigned to LG.Philips LCD Co., Ltd. Invention is credited to Chae, Gee Sung, Chung, In Jae.
Application Number | 20050285507 11/158011 |
Document ID | / |
Family ID | 35504930 |
Filed Date | 2005-12-29 |
United States Patent
Application |
20050285507 |
Kind Code |
A1 |
Chung, In Jae ; et
al. |
December 29, 2005 |
Electro-luminescent device and method for manufacturing the
same
Abstract
An electro-luminescent device includes a transparent substrate,
a black matrix on the transparent substrate defining a plurality of
spaces, a plurality of color representing layers each arranged in
respective ones of the spaces, an overcoat layer on the black
matrix and the color representing layers, a plurality of first
electrodes disposed on the overcoat layer in a first direction with
respect to the color representing layers, a phosphor layer formed
on the plurality of first electrodes, an insulating film on the
phosphor layer, and a plurality of second electrodes disposed on
the insulating film in a second direction perpendicular to the
first direction.
Inventors: |
Chung, In Jae; (Kyeongki-do,
KR) ; Chae, Gee Sung; (Incheon-kwangyokshi,
KR) |
Correspondence
Address: |
MORGAN LEWIS & BOCKIUS LLP
1111 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
20004
US
|
Assignee: |
LG.Philips LCD Co., Ltd
|
Family ID: |
35504930 |
Appl. No.: |
11/158011 |
Filed: |
June 22, 2005 |
Current U.S.
Class: |
313/503 ;
313/504; 313/506 |
Current CPC
Class: |
H05B 33/22 20130101;
H05B 33/26 20130101 |
Class at
Publication: |
313/503 ;
313/504; 313/506 |
International
Class: |
H05B 033/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 25, 2004 |
KR |
P2004-48163 |
Claims
What is claimed is:
1. An electro-luminescent device comprising: a transparent
substrate; a black matrix on the transparent substrate defining a
plurality of spaces; a plurality of color representing layers each
arranged in respective ones of the spaces; an overcoat layer on the
black matrix and the color representing layers; a plurality of
first electrodes disposed on the overcoat layer in a first
direction with respect to the color representing layers; a phosphor
layer formed on the plurality of first electrodes; an insulating
film on the phosphor layer; and a plurality of second electrodes
disposed on the insulating film in a second direction perpendicular
to the first direction.
2. The electro-luminescent device according to claim 1, further
comprising first and second pad terminals on the overcoat layer
respectively disposed at opposite sides of the plurality of first
electrodes, the first electrodes and the first and second pad
terminals being formed of the same material.
3. The electro-luminescent device according to claim 1, wherein the
first electrodes are formed of a transparent metal.
4. The electro-luminescent device according to claim 1, wherein
each of the first electrodes has a double-layer structure including
a first metal film and a second metal film.
5. The electro-luminescent device according to claim 4, wherein the
first metal film is a transparent metal film, and the second metal
film is a molybdenum film.
6. The electro-luminescent device according to claim 4, wherein the
second metal film is formed on a predetermined portion of the first
metal film without completely covering the first metal film.
7. The electro-luminescent device according to claim 4, wherein the
first metal film includes a material selected from the group
consisting of indium tin oxide (ITO), indium zinc oxide (IZO), and
indium tin zinc oxide (ITZO).
8. The electro-luminescent device according to claim 1, further
comprising first and second pad terminals on the overcoat layer
respectively disposed at opposite sides of the plurality of first
electrodes, each of the first and second pad terminals having a
laminated structure of a transparent metal film and a molybdenum
film.
9. The electro-luminescent device according to claim 8, wherein the
molybdenum film is formed on an edge portion of the transparent
metal film without completely covering the transparent metal
film.
10. The electro-luminescent device according to claim 1, wherein
the second electrodes are formed of Al--Ti.
11. The electro-luminescent device according to claim 1, wherein
the second electrodes are formed of aluminum.
12. The electro-luminescent device according to claim 1, wherein
the phosphor layer is a blue phosphor layer.
13. The electro-luminescent device according to claim 1, wherein
each of the color representing layers includes a color filter
layer.
14. The electro-luminescent device according to claim 1, wherein
each of the color representing layers includes a color changing
medium layer.
15. The electro-luminescent device according to claim 1, wherein
the color representing layers are substantially flush with the
black matrix layers.
16. The electro-luminescent device according to claim 1, wherein
each of the color representing layers overlaps facing ends of
adjacent portions of the black matrix associated with the color
representing layer.
17. The electro-luminescent device according to claim 1, wherein
the black matrix is formed of a thin film of chromium or a
carbon-based organic material.
18. A method for manufacturing an electro-luminescent device,
comprising the steps of: forming a black matrix on a transparent
substrate, the black matrix defining a plurality of spaces; forming
color representing layers each arranged in respective ones of the
spaces; forming an overcoat layer over an entire surface of the
transparent substrate including the color representing layers;
forming a plurality of first electrodes on the overcoat layer on
the overcoat layer in a first direction with respect to the color
representing layers; forming a phosphor layer on the plurality of
first electrodes; forming an insulating film on the phosphor layer;
and forming a plurality of second electrodes on the insulating film
in a second direction perpendicular to the first direction.
19. The method according to claim 18, wherein the color
representing layers are formed using a method selected from the
group consisting of a dyeing method, a printing method, an
electro-deposition method, a pigment-dispersion method, and a film
transfer method.
20. The method according to claim 18, wherein the color
representing layers are substantially flush with the black
matrices.
21. The method according to claim 18, wherein the first electrodes
are formed using a shadow mask of a transparent metal selected from
the group consisting of indium tin oxide (ITO), indium zinc oxide
(IZO), and indium tin zinc oxide (ITZO).
22. The method according to claim 18, wherein the step of forming
the first electrodes includes depositing a transparent metal film
over the transparent substrate and selectively removing the
transparent metal film using a photolithography process.
23. The method according to claim 18, wherein the step of forming
the first electrodes includes depositing a transparent metal film
over the transparent substrate and selectively removing the
transparent metal film using a laser ablation technique.
24. The method according to claim 18, wherein the phosphor layer is
formed using a spin coating method or a printing method.
25. The method according to claim 18, wherein the insulating film
is formed using a printing method.
26. The method according to claim 18, wherein the step of forming
the second electrodes includes depositing a metal film having a
laminated Al/Ti film structure and selectively removing the metal
film using a photolithography process.
27. The method according to claim 26, wherein the selective removal
of the metal film is includes a wet etching process.
28. The method according to claim 18, wherein the second electrodes
are formed by a printing method using a shadow mask.
29. The method according to claim 18, wherein the second electrodes
include aluminum or silver.
30. The method according to claim 18, wherein each of the color
representing layers comprises one of a color filter layer and a
color changing medium layer.
31. The method according to claim 18, wherein the phosphor layer
comprises a blue phosphor layer.
32. The method according to claim 18, wherein the step of forming
the plurality of first electrodes includes forming first and second
pad terminals on the overcoat layer respectively disposed at
opposite sides of a region where the first electrodes are arranged,
the first and second pad terminals being formed simultaneously with
the first electrodes.
33. A method for manufacturing an electro-luminescent device,
comprising the steps of: forming a black matrix on a transparent
substrate, the black matrix defining a plurality of spaces; forming
color representing layers each arranged in respective ones of the
spaces; forming an overcoat layer over an entire surface of the
transparent substrate including the color representing layers;
forming a plurality of first electrodes on the overcoat layer in a
first direction with respect to the color representing layers, each
of the first electrodes having a double-layer structure including a
first metal film and a second metal film; forming first and second
pad terminals on the overcoat layer respectively disposed at
regions opposite where the first electrodes are arranged such that
the first and second pad terminals are spaced from the region where
the first electrodes are arranged; forming a phosphor layer on the
first electrodes; forming an insulating film on the phosphor layer
and portions of the first and second pad terminals; and forming a
plurality of second electrodes on the insulating film connected to
the first pad terminal such that the second electrodes are
uniformly spaced apart from one another in a second direction
perpendicular to the first direction.
34. The method according to claim 33, wherein the black matrix
includes a thin film of chromium or a carbon-based organic
material.
35. The method according to claim 33, wherein the first electrodes
and the first and second pad electrodes are simultaneously
formed.
36. The method according to claim 33, wherein the step of forming
the first electrodes comprises the steps of: sequentially forming a
transparent metal film and a molybdenum film over the overcoat
layer; forming a patterned photoresist mask by coating a
photoresist over the molybdenum film, patterning the photoresist
using diffraction exposure, and applying a developing processes to
the exposed photoresist; selectively removing the molybdenum film
and the transparent metal film using the patterned photoresist as a
mask to form the first electrodes spaced apart from one another in
the first direction; ashing the remaining photoresist; selectively
removing the molybdenum film formed on the transparent metal film
in each of the first electrodes to expose a portion of the
transparent metal film; and removing the photoresist.
37. The method according to claim 36, wherein the step of
selectively removing the molybdenum film includes a dry etching
process.
38. The method according to claim 33, wherein the phosphor layer is
formed using a spin coating method or a printing method.
39. The method according to claim 33, wherein the insulating film
is formed using a printing method.
40. The method according to claim 33, wherein the second electrodes
are formed using a printing method with a shadow mask.
41. The method according to claim 33, wherein the step of forming
second electrodes includes depositing an aluminum film, and
selectively removing the aluminum film using a wet etching process
with a portion of the aluminum film being masked.
42. The method according to claim 33, wherein each of the color
representing layers comprises a color filter layer.
43. The method according to claim 33, wherein each of the color
representing layers comprises a color changing medium layer.
44. The method according to claim 33, wherein the phosphor layer
comprises a blue phosphor layer.
Description
[0001] This application claims the benefit of the Korean Patent
Application No. P2004-048163, filed on Jun. 25, 2004 which is
hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a display device, and more
particularly, to an electro-luminescent device and a method for
manufacturing the same.
[0004] 2. Discussion of the Related Art
[0005] Recently, the display industry has flourished with the
introduction of TFT-LCDs to the TV market, the growth of plasma
display panel (PDP) TVs, the advent of next-generation displays
such as organic electro-luminescent (EL) devices, and the like. In
particular, the advent of diverse displays has been mainly
concentrated on application to TVs and mobile equipment, thereby
enabling consumers to select desired displays among a wide variety
of displays. Also, it is expected that the advent of an inorganic
EL device, the driving principle of which is similar to that of
organic EL devices, will provide consumers with an opportunity to
select another display in the future, even though such an inorganic
EL device is still a nascent technology and has yet to enter the
market.
[0006] Organic EL devices, as developed recently, have been used
since 2002 for consumer goods such as displays for mobile phones.
However, inorganic EL devices have yet to be widely recognized for
consumer applications. Although inorganic EL devices are different
from organic EL devices in terms of the manufacturing processes and
whether the luminous material is an organic material or an
inorganic material, inorganic EL devices have the same driving
mechanism (using an electric field) as organic EL devices.
[0007] However, inorganic EL devices are improper for miniature
devices (for example, mobile equipment) because inorganic EL
devices involve electrical shock danger due to their high driving
voltage in contrast to organic EL devices. On the other hand,
inorganic EL devices have an advantage in larger displays because
thin film transistors (TFTs) are unnecessary. In addition,
inorganic EL devices are similar to PDPs in terms of the driving
system because high driving voltages for luminescence of the
inorganic material is necessary.
[0008] As compared to other displays, inorganic EL devices have
remarkable advantages of low costs according to their simple
manufacturing processes and of stable performance even in harsh
environments. The inorganic EL devices also have a great advantage
in that products can be manufactured using an inexpensive thin film
process, as compared to TFT-LCDs and organic EL devices which
require the use of thin film processes.
[0009] FIG. 1 is a circuit diagram schematically illustrating a
general EL panel. As shown in FIG. 1, the EL panel includes gate
lines GL1 to GLm and data lines DL1 to DLn which are arranged on a
glass substrate 10 intersecting with each other. The EL panel also
includes pixel elements PE each arranged at an intersection between
each of the gate lines GL1 to GLm and each of the data lines DL1 to
DLn.
[0010] Each pixel element PE is activated when a gate signal on an
associated one of the gate lines GL1 to GLm is enabled. In the
activated state, the pixel element PE emits light with an intensity
corresponding to the level of a pixel signal on an associated one
of the data lines DL1 to DLn.
[0011] To drive the EL panel, a gate driver 12 is connected to the
gate lines GL1 to GLm, and a data driver 14 is connected to the
data lines DL1 to DLn. The gate driver 12 sequentially activates
the gate lines GL1 to GLm. The data driver 14 supplies pixel
signals to the pixel elements PE via the data lines DL1 to DLn,
respectively.
[0012] The pixel elements PE, which are driven by the gate drivers
12 and data drivers 14, will now be described. FIG. 2 is a circuit
diagram illustrating one pixel element in the EL panel of FIG.
1.
[0013] As shown in FIG. 2, the pixel element includes an EL cell
OLED having a cathode terminal connected to the ground, and a cell
driving circuit 16 adapted to drive the EL cell OLED in accordance
with a signal on a gate line GL and a signal on a data line DL. The
EL cell driving circuit 16 includes a first PMOS TFT T1 adapted to
perform a switching operation for the data signal on the data line
DL in accordance with the signal on the gate line GL, and a second
PMOS TFT T2 adapted to supply a voltage to the EL cell OLED in
accordance with the data signal on the data line DL. The EL cell
driving circuit 16 also includes a storage capacitor Cst connected
between gate and source terminals of the second PMOS TFT T2 to
maintain the data signal received via the first PMOS TFT T1 for a
predetermined time.
[0014] Hereinafter, a related art method for manufacturing an EL
device will be described with reference to the drawings. FIGS. 3A
to 3E are sectional views illustrating processing steps of the
related art EL device manufacturing method.
[0015] As shown in FIG. 3A, first electrodes 22 are first formed on
a transparent substrate 21 such that the first electrodes 22 are
uniformly spaced apart from one another in a column direction,
using a method in which an organic material containing metal grains
is printed on the transparent substrate 21. Here, each first
electrode 22 is a reflective electrode made of Al exhibiting
excellent reflectivity.
[0016] Thereafter, as shown in FIG. 3B, an insulating film 23 is
formed over the entire surface of the transparent substrate 21 such
that a predetermined portion of each first electrode 22 at one side
of the first electrode 22 is exposed. The first electrodes 22
exposed through the insulating film 23 function as first pad
terminals, respectively.
[0017] As shown in FIG. 3C, a phosphor layer 24 is then formed on
the insulating film 23 in accordance with a sputtering method under
the condition in which a shadow mask (not shown) is used. For the
phosphor layer 24, a blue phosphor layer may be used.
[0018] Subsequently, as shown in FIG. 3D, transparent metal (for
example, indium tin oxide (ITO) or the like) is deposited over the
entire surface of the transparent substrate 21 including the
phosphor layer 24 in accordance with a sputtering method. The
transparent metal deposited in accordance with the sputtering
method is then selectively removed using a laser ablation
technique, to form a plurality of second electrodes 25 uniformly
spaced apart from one another in a row direction perpendicular to
the first electrodes 22. The second electrodes 25 function as
transparent electrodes, respectively. The second electrode 25,
which is arranged at one outermost portion of the substrate 21
corresponding to the side of the first pad terminals, is a second
pad terminal.
[0019] Thereafter, red (R), green (G), and blue (B) color
representing layers 26 are formed around the second electrodes 25,
as shown in FIG. 3E. A protective film (not shown) is formed over
the entire surface of the resulting structure of the EL device
obtained in accordance with the above-mentioned processes, to
protect the EL device. After performing a sealing process, the EL
device is connected to driving circuits or chips via the first and
second pad terminals, using TCPs. That is, the EL device is
connected to a gate driver and a data driver to receive signals
from the drive, thereby displaying an image.
[0020] However, the above-mentioned related art EL device
manufacturing method has various problems. That is, first, the
phosphor layer may be damaged when the transparent metal layer is
deposited over the phosphor layer and is then selectively removed
to form the second electrodes (transparent electrodes). As a
result, the throughput may be degraded. Second, addition of a
function to reduce the damage is necessary. Furthermore, the second
electrodes are formed using laser ablation because the phosphor
layer exhibits poor resistance to wet etching. For this reason, the
utility of existing LCD manufacturing equipment is degraded.
SUMMARY OF THE INVENTION
[0021] Accordingly, the present invention is directed to an EL
device and a method for manufacturing the same that substantially
obviate one or more problems due to limitations and disadvantages
of the related art.
[0022] An object of the present invention is to provide an EL
device and a method for manufacturing the same, which do not use a
laser ablation technique, but use a wet etching process while
protecting a phosphor layer from wetnes, thereby being capable of
preventing a degradation in the utility of equipment while
achieving an enhancement in throughput and process
reproducibility.
[0023] Additional advantages, objects, and features of the
invention will be set forth in part in the description which
follows and in part will become apparent to those having ordinary
skill in the art upon examination of the following or may be
learned from practice of the invention. The objectives and other
advantages of the invention may be realized and attained by the
structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
[0024] To achieve these objects and other advantages and in
accordance with the purpose of the invention, as embodied and
broadly described herein, an electro-luminescent device comprises a
transparent substrate; a black matrix on the transparent substrate
defining a plurality of spaces; a plurality of color representing
layers each arranged in respective ones of the spaces; an overcoat
layer on the black matrix and the color representing layers; a
plurality of first electrodes disposed on the overcoat layer in a
first direction with respect to the color representing layers; a
phosphor layer formed on the plurality of first electrodes; an
insulating film on the phosphor layer; and a plurality of second
electrodes disposed on the insulating film in a second direction
perpendicular to the first direction.
[0025] In another aspect, a method for manufacturing an
electro-luminescent device comprises the steps of forming a black
matrix on a transparent substrate, the black matrix defining a
plurality of spaces; forming color representing layers each
arranged in respective ones of the spaces; forming an overcoat
layer over an entire surface of the transparent substrate including
the color representing layers; forming a plurality of first
electrodes on the overcoat layer on the overcoat layer in a first
direction with respect to the color representing layers; forming a
phosphor layer on the plurality of first electrodes; forming an
insulating film on the phosphor layer; and forming a plurality of
second electrodes on the insulating film in a second direction
perpendicular to the first direction.
[0026] In another aspect, a method for manufacturing an
electro-luminescent device comprises the steps of forming a black
matrix on a transparent substrate, the black matrix defining a
plurality of spaces; forming color representing layers each
arranged in respective ones of the spaces; forming an overcoat
layer over an entire surface of the transparent substrate including
the color representing layers; forming a plurality of first
electrodes on the overcoat layer in a first direction with respect
to the color representing layers, each of the first electrodes
having a double-layer structure including a first metal film and a
second metal film; forming first and second pad terminals on the
overcoat layer respectively disposed at regions opposite where the
first electrodes are arranged such that the first and second pad
terminals are spaced from the region where the first electrodes are
arranged; forming a phosphor layer on the first electrodes; forming
an insulating film on the phosphor layer and portions of the first
and second pad terminals; and forming a plurality of second
electrodes on the insulating film connected to the first pad
terminal such that the second electrodes are uniformly spaced apart
from one another in a second direction perpendicular to the first
direction.
[0027] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiments of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
[0029] FIG. 1 is a circuit diagram schematically illustrating a
related art EL panel;
[0030] FIG. 2 is a circuit diagram illustrating one pixel element
in the EL panel of FIG. 1;
[0031] FIGS. 3A to 3E are sectional views illustrating processing
steps of a related art EL device manufacturing method,
respectively;
[0032] FIG. 4 is a sectional view illustrating a structure of an EL
device according to a first exemplary embodiment of the present
invention;
[0033] FIGS. 5A to 5E are sectional views illustrating steps of a
method for manufacturing the EL device according to the first
embodiment of the present invention;
[0034] FIG. 6 is a sectional view illustrating a structure of an EL
device according to a second exemplary embodiment of the present
invention; and
[0035] FIGS. 7A to 7H are sectional views illustrating steps of a
method for manufacturing the EL device according to the second
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers will be used throughout the drawings to
refer to the same or like parts.
[0037] FIG. 4 is a sectional view illustrating a structure of an EL
device according to a first exemplary embodiment of the present
invention.
[0038] As shown in FIG. 4, the EL device according to the first
exemplary embodiment of the present invention includes a plurality
of black matrices 52 which are arranged on a transparent substrate
51 and are uniformly spaced apart from one another. The black
matrices 52 are made of a metal such as chromium or a carbon-based
organic material to have a thin film structure. The EL device also
includes R, G, and B color representing layers 53 each arranged
between adjacent ones of the black matrices 52, an overcoat layer
54 formed over the entire surface of the transparent substrate 51
including the color representing layers 53, a plurality of first
electrodes 55 formed on the overcoat layer 54 to extend in a column
direction while being uniformly spaced apart from one another in a
row direction, and first and second pad terminals 55a and 55b
respectively formed at opposite outermost portions of the overcoat
layer 54 while being spaced apart in the row direction from an
electrode region where the first electrodes 55 are arranged. The EL
device further includes a phosphor layer 56 formed at the electrode
region to cover the first electrodes 55, an insulating film 57
formed on the transparent substrate 51 including the phosphor layer
56 while allowing predetermined portions of the first and second
pad terminals 55a and 55b to be exposed, and a plurality of second
electrodes 58 formed on the insulating film 57 to extend in the row
direction perpendicular to the first electrodes 55 while being
uniformly spaced apart from one another in the column
direction.
[0039] Each color representing layer 53 may comprise a color filter
layer generally used in LCDs. Where the phosphor layer 56 is a blue
phosphor layer, a color changing medium (CCM) may be used for each
color representing layer 53. Also, each color representing layer 53
is formed between adjacent ones of the black matrices 52 to be
flush with the black matrices 52.
[0040] The first electrodes 55 correspond to respective color
representing layers 53. Each first electrode 55 is made of a
transparent conductive material, for example, indium tin oxide
(ITO) or indium zinc oxide (IZO). Each second electrode 58 is made
of a metal exhibiting excellent reflectivity, such as Al.
[0041] Hereinafter, a method for manufacturing the EL device having
the above-described structure according to the first exemplary
embodiment of the present invention will be described. FIGS. 5A to
5E are sectional views illustrating processing steps of the method
for manufacturing the EL device according to the first embodiment
of the present invention.
[0042] As shown in FIG. 5A, black matrices 52, which divide the
color filter pattern cells and shield light, are formed on a
transparent substrate 51. The black matrices 52 are made of a metal
such as chromium or a carbon-based organic material to have a thin
film structure.
[0043] Thereafter, R, G, and B color representing layers 53 are
formed between adjacent ones of the black matrices 52,
respectively. The formation of the color representing layers 53 may
be achieved using a dyeing method, a printing method, an
electro-deposition method, a pigment dispersion method, or a film
transfer method.
[0044] The pigment dispersion method is a method wherein a color
representing layer is formed from a photoresist film of a
photoresist material with a pigment dispersed therein using
sequential processes of coating, exposure, development, baking, and
the like. Using this method, R, G, and B color representing layers
can be formed. That is, the R, G, and B color representing layers
are formed by coating a photoresist over the transparent substrate
51 formed with the black matrices 52, using a spin coating method,
and then exposing and developing the photoresist. For the formation
of the R, G, and B color representing layers 53, screen masks
respectively formed with R, G, and B patterns are used. Through a
single process, color representing layers 53 respectively having R,
G, and B patterns may be simultaneously formed.
[0045] An overcoat layer 54, which is a protective layer having
insulating and leveling functions, is then formed over the entire
surface of the transparent substrate 51 including the color
representing layers 53. Subsequently, as shown in FIG. 5B, a
plurality of first electrodes 55 and first and second pad
electrodes 55a and 55b are formed on the transparent substrate 51
with the overcoat layer 54 where a transparent metal, such as ITO,
IZO, or indium tin zinc oxide (ITZO), is used as a shadow mask so
that the first electrodes 55 extend in the column direction while
being uniformly spaced apart from one another in the row direction,
and the first and second pad electrodes 55a and 55b are arranged at
opposite outermost portions of the substrate 51 in the row
direction, respectively. The first electrodes 55 correspond to
respective color representing layers 53.
[0046] Although the first electrodes 55 have been described as
being formed using a shadow mask in the illustrated exemplary case,
the first electrodes 55 may be formed by depositing a transparent
metal using a sputtering process and subjecting the transparent
metal to a photolithography process. Also, the first electrodes 55
may be formed by selectively removing the transparent metal using a
laser ablation technique.
[0047] Next, a phosphor material layer 56 is formed on the
transparent substrate 51 with the first electrodes 55 using a spin
coating or printing method, as shown in FIG. 5C. During the
formation of the phosphor layer 56, the first and second pad
terminals 55a and 55b are maintained in a masked state. Where a
blue phosphor layer is used for the phosphor layer 56, a CCM layer
may be used for each color representing layer 53.
[0048] Thereafter, as shown in FIG. 5D, an insulating film 57 is
formed on the transparent substrate 51 using a printing method such
that predetermined portions of the first and second pad terminals
55a and 55b are exposed. Although the formation of the insulating
film 57 has been described as being achieved using a printing
method, the insulating film 57 may alternatively be formed by
depositing an insulating material using a sputtering or chemical
vapor deposition (CVD) method, and selectively removing
predetermined portions of the deposited film using a
photolithography process.
[0049] A metal film of laminated Al/Ti films is then deposited over
the entire surface of the transparent substrate 51 including the
insulating film 57. The metal film is subsequently selectively
removed through a photolithography process to form a plurality of
second electrodes 58, as shown in FIG. 5E, extending in a direction
perpendicular to the first electrodes 55 while being uniformly
spaced apart from one another.
[0050] Even when a wet etching process is used for the formation of
the second electrodes 58, damage to the phosphor layer 56 can be
prevented because the insulating film 57 covers the phosphor layer
56. Meanwhile, the second electrodes 58 may alternatively be formed
through a printing method using a shadow mask. For the metal film
of the second electrodes 58, Al or Ag exhibiting excellent
reflectivity may be used.
[0051] The second electrodes 58 are connected to the first pad
terminal 55a which is, in turn, electrically connected with an
external driving circuit via TCPs (not shown), along with the
second pad terminal 55b. Accordingly, each second electrode 58 can
receive a signal from the external driving circuit.
[0052] FIG. 6 is a sectional view illustrating a structure of an EL
device according to a second exemplary embodiment of the present
invention.
[0053] As shown in FIG. 6, the EL device according to the second
embodiment of the present invention includes a plurality of black
matrices 72 which are arranged on a transparent substrate 71 and
are uniformly spaced apart from one another. The black matrices 72
is made of a metal such as chromium or a carbon-based organic
material to have a thin film structure. The EL device also includes
R, G, and B color representing layers 73 each arranged between
adjacent ones of the black matrices 72, an overcoat layer 74 formed
over the entire surface of the transparent substrate 71 including
the color representing layers 73, and a plurality of first
electrodes 78 formed on the overcoat layer 74 to extend in a column
direction while being uniformly spaced apart from one another in a
row direction. Each first electrode 78 is formed at a position
corresponding to an associated one of the color representing layers
73, and has a double-layer structure of a transparent metal film 75
and a molybdenum film 76. The EL device further includes first and
second pad terminals 78a and 78b respectively formed at opposite
outermost portions of the overcoat layer 74 while being spaced
apart in the row direction from an electrode region where the first
electrodes 78 are arranged. The EL device further includes a
phosphor layer 79 formed at the electrode region on the transparent
substrate 71 to cover the first electrodes 78, an insulating film
80 formed on the transparent substrate 71 including the phosphor
layer 79 while allowing predetermined portions of the first and
second pad terminals 78a and 78b to be exposed, and second
electrodes 81 formed on the insulating film 80 to be connected to
the first pad terminal 78a while extending in the row direction
perpendicular to the first electrodes 78 in a state of being
uniformly spaced apart from one another in the column
direction.
[0054] Each first electrode 78 has a double-layer structure of the
transparent metal film 75 and molybdenum film 76. The molybdenum
film 76, which is formed on the transparent metal film 75, is
arranged at an edge region of the transparent metal film 75 except
for an opening region (light transmission region) of the
transparent metal film 75 without completely covering the
transparent metal film 75.
[0055] The first and second pad terminals 78a and 78b are partially
exposed for TCP bonding. Each color representing layer 73 is
arranged between adjacent ones of the black matrices 72 such that
the color representing layer 73 overlap the facing ends of the
adjacent black matrices 72. The color representing layers 73 are
arranged repeatedly in the order of R, G, and B while being spaced
apart from one another.
[0056] Each color representing layer 73 may comprise a color filter
layer generally used in LCDs. Where the phosphor layer 79 is a blue
phosphor layer, a CCM may be used for each color representing layer
73. The arrows in FIG. 6 show a principle wherein R, G, and B
visible rays emitted from the phosphor layer 79 via respective R,
G, and B color representing layers 73 are transmitted through the
first electrodes 78.
[0057] Hereinafter, a method for manufacturing the EL device having
the above-described structure according to the second embodiment of
the present invention will be described. FIGS. 7A to 7H are
sectional views illustrating processing steps of the method for
manufacturing the EL device according to the second exemplary
embodiment of the present invention.
[0058] As shown in FIG. 7A, black matrices 72, which divide cells
of color filter patterns, and function to shield light, are formed
on a transparent substrate 71. The black matrices 72 are made of a
metal such as chromium or a carbon-based organic material as a thin
film.
[0059] Thereafter, R, G, and B color representing layers 73 are
formed between adjacent ones of the black matrices 72,
respectively, as shown in FIG. 7B. The formation of the color
representing layers 73 may be achieved using a dyeing method, a
printing method, an electro-deposition method, a pigment dispersion
method, or a film transfer method.
[0060] As described above, the pigment dispersion method is a
method wherein a color representing layer is formed from a
photoresist film made of a photoresist dispersed with a pigment
using sequential processes of coating, exposure, development,
baking, and the like. Using this method, R, G, and B color
representing layers can be formed. That is, the R, G, and B color
representing layers are formed by coating a photoresist over the
transparent substrate 71 formed with the black matrices 72 using a
spin coating method, and then exposing and developing the
photoresist. For the formation of the R, G, and B color
representing layers 73, screen masks respectively formed with R, G,
and B patterns are used. Through a single process, color
representing layers 73 respectively having R, G, and B patterns may
be simultaneously formed.
[0061] An overcoat layer 74, which is a protective layer having
insulating and leveling functions, is then formed over the entire
surface of the transparent substrate 71 including the color
representing layers 73. Subsequently, as shown in FIG. 7C, a
transparent metal film 75 made of ITO, IZO, or ITZO, and a
molybdenum film 76 are sequentially formed over the transparent
substrate 71 formed with the overcoat layer 74.
[0062] Thereafter, a photoresist 77 is coated over the molybdenum
film 76. The photoresist 77 is then patterned using diffraction
exposure and development processes. When the diffraction exposure
process is carried out to expose the entire surface of the
photoresist 77 to light under the condition in which a diffraction
mask--having a slit region, a shield region, and a transmission
region--is arranged above the photoresist 77 with the portion of
the photoresist 77 corresponding to the transmission region is
completely exposed to the light. In contrast, the portion of the
photoresist 77 corresponding to the shield region is not exposed to
the light. The portion of the photoresist 77 corresponding to the
slit region is partially exposed to the light so that the
photoresist 77 remains at the portion corresponding to the slit
region in a thickness less than that of the other portion of the
photoresist 77.
[0063] Using the patterned photoresist 77 as a mask, the molybdenum
film 76 and transparent metal film 75 are primarily selectively
removed to form a plurality of first electrodes 78 extending in the
column direction while being uniformly spaced apart from one
another in the row direction, as shown in FIG. 7D. Simultaneously
with the formation of the first electrodes 78, first and second pad
electrodes 78a and 78b are formed at regions arranged adjacent to
outermost ones of the first electrodes 78 in the row direction,
respectively. The first and second pad electrodes 78a and 78b are
TCP bonding regions for application of signals from external
driving circuits, respectively. The first electrodes 78 are formed
to correspond to respective color representing layer 73.
[0064] As shown in FIG. 7E, the patterned photoresist 77 is then
subjected to an ashing process such that only the portion of the
photoresist 77 corresponding to the shield region of the
diffraction mask remains. Using the remaining photoresist 77 as a
mask, the molybdenum film 76 is selective removed to form the first
electrodes 78 which extend in the column direction while being
uniformly spaced apart from one another in the row direction. That
is, the portion of the photoresist 77 corresponding to the slit
region of the diffraction mask is removed in the ashing process. In
this case, the other portion of the photoresist 77 remains in a
predetermined thickness. Using the remaining photoresist 77 as a
mask, only the molybdenum film 76 arranged on the transparent metal
film 75 is selectively removed to expose the transparent metal film
75.
[0065] The removal of the molybdenum film 76 is achieved through a
dry etching process. The portion of the transparent metal film 75
corresponding to a region, from which the molybdenum film 76 is
removed, is an opening region (light transmission region).
Subsequently, the photoresist 77 used as the mask to form the first
electrodes 78 is removed.
[0066] As shown in FIG. 7F, a phosphor material layer 79 is then
formed on the transparent substrate 71 with the first electrodes 78
using a spin coating or printing method. During the formation of
the phosphor layer 79, the first and second pad terminals 78a and
78b are maintained in a masked state. Where a blue phosphor layer
is used for the phosphor layer 79, a CCM layer may be used for each
color representing layer 73.
[0067] Thereafter, as shown in FIG. 7G, an insulating film 80 is
formed on the transparent substrate 71 formed with the phosphor
layer 79, using a printing method, such that predetermined portions
of the first and second pad terminals 78a and 78b are exposed.
Although the formation of the insulating film 80 has been described
as being achieved using a printing method, the insulating film 80
may alternatively be formed by depositing an insulating material
using a sputtering or CVD method and then selectively removing
predetermined portions of the deposited film using a
photolithography process.
[0068] A metal film consisting of laminated Al/Ti films is then
deposited over the entire surface of the transparent substrate 71
including the insulating film 80. The metal film is subsequently
selectively removed through a photolithography process to form a
plurality of second electrodes 81, as shown in FIG. 7H, extending
in the row direction perpendicular to the first electrodes 78 while
being uniformly spaced apart from one another in the column
direction.
[0069] The second electrodes 81 are electrically connected to the
first pad terminal 78a. In the illustrated example, the first pad
terminal 78a has the same double-layer structure as the first
electrodes 78, so that the first pad terminal 78a includes the
transparent metal film 75 and the molybdenum film 76. In this case,
the second electrodes 81 are electrically connected to the
molybdenum film 76 of the first pad terminal 78a. The transparent
metal film 75 of the first pad terminal 78a, which is not
electrically connected with the second electrodes 81, is a TCP
bonding region for application of a signal from the associated
external driving circuit.
[0070] Even when a wet etching process is used for the formation of
the second electrodes 81, damage of the phosphor layer 79 is
prevented because the insulating film 80 covers the phosphor layer
79. Meanwhile, the second electrodes 81 may alternatively be formed
through a printing method using a shadow mask. For the metal film
of the second electrodes 81, Al or Ag exhibiting excellent
reflectivity may be used.
[0071] The above-described EL device and manufacturing method
thereof according to the present invention have various effects.
First, it is possible to achieve an enhancement in throughput
because the phosphor layer is protected by the insulating film
after the formation of the phosphor layer to prevent the phosphor
layer from being exposed to various treating agents used in
subsequent processes, and to protect the phosphor layer against
humidity. Second, since the second electrodes (reflective
electrodes) extending in the row direction electrically contact the
pad having the double-layer structure of the transparent metal film
and molybdenum film, it is possible to solve problems associated
with contact resistance and to prevent an electro-etch phenomenon
from occurring during the etching process. Third, it is possible to
enhance the utility of equipment, using a color filter
manufacturing technique for the manufacture of LCDs.
[0072] It will be apparent to those skilled in the art that various
modifications and variations can be made in the electro-luminescent
device and method for manufacturing the same of the present
invention without departing from the spirit or scope of the
invention. Thus, it is intended that the present invention cover
the modifications and variations of this invention provided they
come within the scope of the appended claims and their
equivalents.
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