U.S. patent application number 14/572109 was filed with the patent office on 2015-05-21 for method for manufacturing a display unit.
The applicant listed for this patent is Sony Corporation. Invention is credited to Masaru Yamaguchi.
Application Number | 20150137106 14/572109 |
Document ID | / |
Family ID | 32501273 |
Filed Date | 2015-05-21 |
United States Patent
Application |
20150137106 |
Kind Code |
A1 |
Yamaguchi; Masaru |
May 21, 2015 |
METHOD FOR MANUFACTURING A DISPLAY UNIT
Abstract
A method for manufacturing a display unit is provided, and the
method includes forming a first insulating film, forming a
plurality of first electrodes on the first insulating film, forming
a second insulating film on the first electrodes, forming a
plurality of openings corresponding to the first electrodes,
forming a plurality of organic layers formed in a shape of a stripe
having notch parts, forming a second electrode on the organic layer
having the notch parts is formed, and forming a protective film on
the second electrode.
Inventors: |
Yamaguchi; Masaru;
(Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sony Corporation |
Tokyo |
|
JP |
|
|
Family ID: |
32501273 |
Appl. No.: |
14/572109 |
Filed: |
December 16, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14454261 |
Aug 7, 2014 |
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14572109 |
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11870226 |
Oct 10, 2007 |
8828477 |
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14454261 |
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10840074 |
May 6, 2004 |
7303635 |
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11870226 |
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Current U.S.
Class: |
257/40 |
Current CPC
Class: |
H01L 27/3211 20130101;
H01L 51/5228 20130101; H01L 51/5206 20130101; H01L 2251/558
20130101; H01L 2251/5315 20130101; H01L 51/005 20130101; H01L
27/3244 20130101; H01L 51/5212 20130101; H01L 27/32 20130101; H01L
51/5012 20130101; H01L 51/0011 20130101; H01L 51/0062 20130101;
H01L 51/0012 20130101; H01L 51/0081 20130101; H01L 51/0059
20130101; H01L 2251/301 20130101; H01L 51/5253 20130101; H01L 51/56
20130101; H01L 51/5221 20130101; H01L 2251/303 20130101; C23C
14/042 20130101; H01L 51/0008 20130101; H01L 51/5262 20130101; H01L
51/0035 20130101; H01L 2227/323 20130101; H01L 27/3276 20130101;
H01L 51/5203 20130101 |
Class at
Publication: |
257/40 |
International
Class: |
H01L 27/32 20060101
H01L027/32; H01L 51/52 20060101 H01L051/52 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 2003 |
JP |
2003-132791 |
Claims
1. A display unit comprising: a first insulating film; a plurality
of anode electrodes disposed on the first insulating film; a second
insulating film disposed on the anode electrodes; a plurality of
organic layers disposed on the anode electrodes; a cathode
electrode disposed on the organic layer; an extraction electrode; a
first wiring provided in a peripheral area of the plurality of
anode electrodes; and a second wiring provided between two anode
electrodes adjacent to one another in a column direction, wherein
the cathode electrode is connected to the extraction electrode via
the first wiring, and wherein the second wiring includes a
plurality of contact regions, each of contact regions is disposed
at the position between two anode electrodes adjacent to one
another in a row direction.
2. The display unit according to claim 1, wherein the organic
layers are provided over the two rows of the anode electrodes,
3. The display unit according to claim 2, wherein the organic
layers have a stripe shape.
4. The display unit according to claim 2, wherein the organic
layers are continuously provided over the two or more lines of the
anode electrodes.
5. The display unit according to claim 2, wherein the organic
layers have a notch part at a portion corresponding to the contact
region.
6. The display unit according to claim 5, wherein the corresponding
notch parts of adjacent organic layers are coincident with one
another.
7. The display unit according to claim 5, wherein the second wiring
connected to the cathode electrode at the contact region.
8. The display unit according to claim 7, wherein the second wiring
is connected to the first wiring.
9. The display unit according to claim 1, wherein the cathode
electrode is made of metal including at least one of silver (Ag),
aluminum (Al), magnesium (Mg), calcium (Ca), and sodium (Na).
10. The display unit according to claim 5, further comprising a
protective film disposed on the cathode electrode.
11. The display unit according to claim 10, wherein the protective
film has a thickness from about 500 nm to about 10,000 nm.
12. The display unit according to claim 10, wherein the protective
film includes at least one of silicon oxide (SiO2) and silicon
nitride (SiN).
13. The display unit according to claim 1, wherein the first
insulating film includes at least one of polyimide and silicon
oxide (SiO2).
14. The display unit according to claim 1, wherein at least a
portion of the first wiring is covered with the cathode electrode
and directly connected to the cathode electrode.
15. The display unit according to claim 1, wherein the first wiring
surrounding the plurality of anode electrodes in the peripheral
area of the display unit.
16. A display unit comprising: a first insulating film; a plurality
of anode electrodes disposed on the first insulating film; a second
insulating film disposed on the anode electrodes; a plurality of
organic layers disposed on the anode electrodes; a cathode
electrode disposed on the organic layer; an extraction electrode; a
first wiring provided in a peripheral area of the plurality of
anode electrodes; and a second wiring provided between two rows of
the anode electrodes adjacent to one another, wherein the cathode
electrode is connected to the extraction electrode via the first
wiring, and wherein the second wiring includes contact region at
the position corresponding to respective anode electrodes.
17. The display unit according to claim 16, wherein the organic
layers are provided over the two rows of the anode electrodes,
18. The display unit according to claim 17, wherein the organic
layers have a stripe shape.
19. The display unit according to claim 17, wherein the organic
layers are continuously provided over the two or more lines of the
anode electrodes.
20. The display unit according to claim 17, wherein the organic
layers have a notch part at a portion corresponding to the contact
region.
21. The display unit according to claim 20, wherein the
corresponding notch parts of adjacent organic layers are coincident
with one another.
22. The display unit according to claim 20, wherein the second
wiring connected to the cathode electrode at the contact
region.
23. The display unit according to claim 22, wherein the second
wiring is connected to the first wiring.
24. The display unit according to claim 16, wherein the cathode
electrode is made of metal including at least one of silver (Ag),
aluminum (Al), magnesium (Mg), calcium (Ca), and sodium (Na).
25. The display unit according to claim 20, further comprising a
protective film disposed on the cathode electrode.
26. The display unit according to claim 25, wherein the protective
film has a thickness from about 500 nm to about 10,000 nm.
27. The display unit according to claim 25, wherein the protective
film includes at least one of silicon oxide (SiO2) and silicon
nitride (SiN).
28. The display unit according to claim 16, wherein the first
insulating film includes at least one of polyimide and silicon
oxide (SiO2).
29. The display unit according to claim 16, wherein at least a
portion of the first wiring is covered with the cathode electrode
and directly connected to the cathode electrode.
30. The display unit according to claim 16, wherein the first
wiring surrounding the plurality of anode electrodes in the
peripheral area of the display unit.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/454,261, filed Aug. 7, 2014, which
application is a continuation of U.S. patent application Ser. No.
11/870,226, filed on Oct. 10, 2007, issued as U.S. Pat. No.
8,828,477 on Sep. 9, 2014, which is a divisional of U.S. patent
application Ser. No. 10/840,074 filed on May 6, 2004, issued as
U.S. Pat. No. 7,303,635 on Dec. 4, 2007, and claims priority to
Japanese Patent Application No. JP2003-132791, filed on May 12,
2003, the disclosure of which is herein incorporated by
reference.
BACKGROUND
[0002] The present invention relates to a deposition mask, a method
for manufacturing a display unit using same, and a display unit.
More specifically the present invention relates to a deposition
mask suitable for manufacturing a display unit using organic light
emitting devices, a method for manufacturing a display unit using
same, and a display unit.
[0003] In recent years, as a display unit instead of a liquid
crystal display, an organic light emitting display which uses
organic light emitting devices has been used. The organic light
emitting display has characteristics that its viewing angle is wide
and its power consumption is low since it is a self-luminous type
display. The organic light emitting display is also thought of as a
display having sufficient response to high-definition high-speed
video signals, and is under development toward the practical
use.
[0004] A conventional organic light emitting display is
manufactured through processes of FIGS. 1 to 7. First, as shown in
FIG. 1, a number of first electrodes 114 are formed on a substrate
111. These first electrodes 114 are patterned for respective
organic light emitting devices, and electrically connected to
unshown TFTs (Thin Film Transistor) which are provided
corresponding to respective organic light emitting devices with an
unshown planarizing layer in between.
[0005] Next, as shown in FIG. 2, an insulating film 115 is formed
in an area between the number of first electrodes 114. This
insulating film 115 is provided with openings 115A corresponding to
the first electrodes 114.
[0006] Subsequently, as shown in FIG. 3, an auxiliary electrode
116A is formed at the position corresponding to the inside of
picture on the insulating film 115, and a trunk-shaped auxiliary
electrode 116B which becomes a bus line for the auxiliary electrode
116A is formed in a peripheral area of the substrate 111. The
auxiliary electrode 116A is provided in order to uniform a wiring
resistance between a power source (not shown) and respective light
emitting parts, and inhibit generation of emission unevenness due
to difference of voltage drop (particularly emission unevenness
between a central part and a peripheral part inside the picture).
Further, on an end of the trunk-shaped auxiliary electrode 116B, an
extraction electrode 116C is provided in order to connect a second
electrode 116 to the power source.
[0007] After that, for example, an organic layer 117 of an organic
light emitting device 110G generating green light is formed as
shown in FIG. 5, by using a deposition mask 140 having openings 141
corresponding to respective organic light emitting devices as shown
in FIG. 4.
[0008] Next, as shown in FIG. 6, an organic layer 117 of an organic
light emitting device 110R generating red light is formed by moving
the deposition mask 140, and as shown in FIG. 5, an organic layer
117 of an organic light emitting device 110B generating blue light
is similarly formed by moving the deposition mask 140 again.
[0009] Subsequently, as shown in FIG. 7, the second electrode 116
is formed almost over the whole area of the substrate 111 by
deposition method. The second electrode 116 and the auxiliary
electrode 116A are thereby electrically connected at a contact part
118.
[0010] Conventionally, for example, a case wherein a rib which
serves as a spacer for a deposition mask to form an organic layer
is provided between respective organic light emitting devices, and
an auxiliary electrode is formed on this rib has been proposed.
See, for example, Japanese Unexamined Patent Application
Publication No. 2001-195008.
[0011] In the conventional deposition mask 140, the openings 141
are provided corresponding to respective organic light emitting
devices (FIG. 4). When deposition is performed by using such a
deposition mask 140, a film thickness distribution may be generated
in the organic layer 117 depending on conditions of deposition from
an evaporation source 152, as shown in FIG. 8. Such a film
thickness distribution varies depending on a plate thickness or a
cross sectional shape of the deposition mask 140, or a physical
relation between the evaporation source 152 and the openings 141 of
the deposition mask 140. In particular, the film thickness
distribution is subject to influence by characteristics of the
evaporation source 152. Light emitting colors, that is, light
emitting wavelengths of the organic light emitting devices depend
on a film thickness of the organic layer 117. Therefore, in order
to prevent color unevenness inside pixels, it is necessary to
utilize only the area in the vicinity of the center of the organic
layer 117 having an even film thickness as an effective light
emitting region 117A. Therefore, there has been a problem that when
using the conventional deposition mask 140, the effective light
emitting region 117A is limited, so that an aperture ratio is
lowered.
SUMMARY
[0012] The present invention relates to a deposition mask, a method
for manufacturing a display unit using same, and a display unit.
More specifically the present invention relates to a deposition
mask suitable for manufacturing a display unit using organic light
emitting devices, a method for manufacturing a display unit using
same, and a display unit.
[0013] In an embodiment, the present invention provides a
deposition mask which can improve an aperture ratio of a display
unit, and a method for manufacturing a display unit using the
deposition mask.
[0014] In another embodiment, the present invention provides a
display unit which is manufactured by using the deposition mask of
the invention, and whose aperture ratio is improved.
[0015] The deposition mask according to an embodiment of the
present invention is provided in order to form a continuous organic
layer common to organic light emitting devices of a display unit
which has a matrix configuration constructed by a number of lines
and columns of the number of organic light emitting devices on a
substrate by deposition method. The deposition mask according to an
embodiment of the present invention includes a body part having one
or more stripe-shaped openings to form a continuous organic layer
common to at least two lines of the matrix configuration, and
protrusions which are provided on the body part to partly protrude
inside the opening.
[0016] The method for manufacturing a display unit according to an
embodiment of the present invention is a method to manufacture a
display unit having a matrix configuration constructed by a number
of lines and columns of a number of organic light emitting devices
on a substrate. The method for manufacturing a display unit
according an embodiment of to the present invention includes
forming a number of first electrodes in the shape of a matrix
corresponding to the respective number of organic light emitting
devices on the substrate; forming an insulating film in an area
between lines and columns of the number of first electrodes;
forming an auxiliary electrode in an area between lines or columns
of the number of first electrodes on the insulating film; forming a
continuous organic layer common to at least two of the number of
first electrodes in the shape of a stripe by deposition, and notch
parts at a position corresponding to an area between lines of the
first electrodes of the stripe-shaped continuous organic layer; and
forming a second electrode covering almost a whole area of the
substrate after the continuous organic layer having the notch parts
is formed, a contact part is formed at the notch parts of the
continuous organic layer, and electrically connecting the second
electrode and the auxiliary electrode.
[0017] The display unit according to an embodiment of the present
invention has a matrix configuration constructed by a number of
lines and columns of a number of organic light emitting devices on
a substrate. The display unit according to the invention comprises:
a number of first electrodes provided on the substrate
corresponding to the respective number of organic light emitting
devices; an insulating film provided in an area between lines or
columns of the number of first electrodes; an auxiliary electrode
provided in an area between lines or columns of the number of first
electrodes on the surface of the insulating film; a stripe-shaped
continuous organic layer, which is provided over at least two lines
of a matrix configuration of the number of organic light emitting
devices in common on the surface of the substrate including the
number of first electrodes, and which has notch parts on its side
wall part corresponding to an area between lines of the number of
first electrodes; and a second electrode, which covers almost a
whole area of the substrate including the continuous organic layer,
and which is electrically connected to the auxiliary electrode
through a contact part formed at the notch parts of the continuous
organic layer.
[0018] In the deposition mask according to an embodiment of the
present invention, the continuous organic layer common to at least
two lines of the matrix configuration constructed by the number of
lines and columns of the number of organic light emitting devices
is formed through the stripe-shaped opening provided on the body
part of the deposition mask. Therefore, a film thickness
distribution is decreased in the extensional direction of the
continuous organic layer. Further, since the protrusions are
provided to partly protrude inside the opening, the notch parts
which become the contact part between the auxiliary electrode and
the second electrode are formed on the continuous organic
layer.
[0019] In the method for manufacturing the display unit according
to an embodiment of the present invention, the number of first
electrodes are formed on the substrate in the shape of a matrix
corresponding to the respective number of organic light emitting
devices. Next, after the insulating film is formed in the area
between lines and columns of the number of first electrodes, the
auxiliary electrode is formed on the insulating film. Subsequently,
the continuous organic layer common to at least two of the number
of first electrodes is formed in the shape of a stripe by
deposition, and the notch parts are formed at the position
corresponding to the area between lines of the first electrodes of
the stripe-shaped continuous organic layer. After that, the second
electrode covering almost the whole area of the substrate is
formed, the contact part is formed at the notch parts of the
continuous organic layer, and the second electrode and the
auxiliary electrode are electrically connected.
[0020] In the display unit according to an embodiment of the
present invention, the stripe-shaped continuous organic layer is
provided over at least two lines of the matrix configuration of the
number of organic light emitting elements in common. Therefore, a
film thickness distribution is decreased in the extensional
direction of the continuous organic layer. Further, the notch parts
are provided on the side wall part of the continuous organic layer
corresponding to the area between lines of the number of first
electrodes, and the auxiliary electrode and the second electrode
are electrically connected through the contact part formed at these
notch parts. Therefore, a wiring resistance difference between the
power source and respective organic light emitting devices is
reduced.
[0021] In an embodiment, the present invention provides a
deposition mask which can improve an aperture ratio of a display
unit, a method for manufacturing a display unit using it, and a
display unit. A red continuous organic layer, a green continuous
organic layer, and a blue continuous organic layer are provided
over two or more lines of a matrix configuration of organic light
emitting devices in common. Differently from the conventional case
wherein the organic layer is formed corresponding to each organic
light emitting device, a film thickness distribution in the
extensional direction of the red continuous organic layer, the
green continuous organic layer, and the blue continuous organic
layer is dissolved, and an aperture ratio can be improved by just
that much. Notch parts are provided for the red continuous organic
layer, the green continuous organic layer, and the blue continuous
organic layer. At these notch parts, a contact part between a
second electrode and an auxiliary electrode is formed. Therefore,
voltage drop of the second electrode can be effectively
inhibited.
[0022] Additional features and advantages of the present invention
are described in, and will be apparent from, the following Detailed
Description of the Invention and the figures.
BRIEF DESCRIPTION OF THE FIGURES
[0023] FIG. 1 is a plane view to explain a method for manufacturing
a conventional display unit.
[0024] FIG. 2 is a plane view to explain a manufacturing process
following a process of FIG. 1.
[0025] FIG. 3 is a plane view to explain a manufacturing process
following the process of FIG. 2.
[0026] FIG. 4 is a plane view to explain a manufacturing process
following the process of FIG. 3.
[0027] FIG. 5 is a plane view to explain a manufacturing process
following the process of FIG. 4.
[0028] FIG. 6 is a plane view to explain a manufacturing process
following the process of FIG. 5.
[0029] FIG. 7 is a plane view to explain a manufacturing process
following the process of FIG. 6.
[0030] FIG. 8 is a cross sectional view to explain a problem area
of a deposition mask used in manufacturing the conventional display
unit.
[0031] FIG. 9 is a plane view showing an outline construction of a
display unit according to an embodiment of the present
invention.
[0032] FIG. 10 is a cross sectional view to explain a manufacturing
process of the display unit shown in FIG. 9.
[0033] FIG. 11 is a plane view regarding a manufacturing process
following the process of FIG. 10.
[0034] FIG. 12 is a cross sectional view taken along line IV-IV of
FIG. 11.
[0035] FIG. 13 is a plane view regarding a manufacturing process
following the processes of FIGS. 11 and 12.
[0036] FIG. 14 is a cross sectional view taken along line VI-VI of
FIG. 13.
[0037] FIG. 15 is a plane view regarding a manufacturing process
following the processes of FIGS. 13 and 14.
[0038] FIG. 16 is a cross sectional view taken along line VIII-VIII
of FIG. 15.
[0039] FIG. 17 is a cross sectional view regarding a manufacturing
process following the processes of FIGS. 15 and 16.
[0040] FIG. 18 is a plane view showing a construction of a
deposition mask shown in FIG. 17.
[0041] FIG. 19 is a plane view showing a condition wherein a green
continuous organic layer is formed by using the deposition mask
shown in FIGS. 17 and 18.
[0042] FIG. 20 is a plane view showing a modification of the
deposition mask shown in FIG. 18.
[0043] FIG. 21 is a plane view showing other modification of the
deposition mask shown in FIG. 18.
[0044] FIG. 22 is a view regarding an outline construction of a
deposition apparatus used in the processes of FIGS. 17 and 19.
[0045] FIG. 23 is a plane view regarding a manufacturing process
following the processes of FIGS. 17 and 19.
[0046] FIG. 24 is a plane view regarding a manufacturing process
following the process of FIG. 23.
[0047] FIG. 25 is a cross sectional view taken along line XVII-XVII
of FIG. 24.
[0048] FIG. 26 is a cross sectional view taken along line
XVIII-XVIII of FIG. 24.
[0049] FIG. 27 is a plane view regarding a manufacturing process
following the process of FIG. 24.
[0050] FIG. 28 is a cross sectional view taken along line XX-XX of
FIG. 27.
[0051] FIG. 29 is a cross sectional view taken along line XXI-XXI
of FIG. 27.
[0052] FIG. 30 is a cross sectional view to regarding a
manufacturing process following the process of FIG. 27.
[0053] FIGS. 31A and 31B are cross sectional views regarding
manufacturing processes following the process of FIG. 30.
[0054] FIG. 32 is a cross sectional view regarding a manufacturing
process following the processes of FIGS. 31A and 31B.
[0055] FIG. 33 is a cross sectional view regarding a manufacturing
process following the process of FIG. 32.
[0056] FIG. 34 is a view regarding an operation of a display unit
shown in FIG. 33.
[0057] FIG. 35 is a plane view showing still another modification
of the deposition mask shown in FIG. 18.
DETAILED DESCRIPTION OF THE INVENTION
[0058] The present invention relates to a deposition mask, a method
for manufacturing a display unit using same, and a display unit.
More specifically the present invention relates to a deposition
mask suitable for manufacturing a display unit using organic light
emitting devices, a method for manufacturing a display unit using
same, and a display unit.
[0059] An embodiment of the present invention will be described in
detail hereinbelow with reference to the drawings.
[0060] With reference to FIGS. 9 to 31B, a method for manufacturing
a display unit according to an embodiment of the invention and a
deposition mask used for the display unit will be described. This
display unit is used, for example, as an ultra thin organic light
emitting display. As shown in FIG. 9, many pixels are arranged in
the shape of a matrix as a whole by constructing a matrix
configuration constructed by a number of lines and columns of
organic light emitting devices 10R, 10G, and 10B on a substrate 11,
setting three primary colors device of the organic light emitting
device 10R generating red light, the organic light emitting device
10G generating green light, and the organic light emitting device
10B generating blue light to one pixel unit.
[0061] In this embodiment, before such organic light emitting
devices 10R, 10G, and 10B are formed, first, as shown in FIG. 10, a
TFT 12 is formed on the substrate 11 made of an insulating material
such as glass, then an interlayer insulating film 12A made of, for
example, silicon oxide, PSG (Phospho-Silicate Glass) or the like is
formed. After that, a wiring 12B made of, for example, aluminum
(Al) or an aluminum (Al)-copper (Cu) alloy is formed as a signal
line. A gate electrode (not shown) of the TFT 12 is connected to an
unshown scanning circuit. A source and a drain (not shown either)
are connected to the wiring 12B through an unshown contact hole
provided on the interlayer insulating film 12A. A construction of
the TFT 12 is not limited particularly, and can be either a bottom
gate type or a top gate type, for example.
[0062] Next, as shown in FIG. 10 as well, a planarizing layer 13
made of an organic material such as polyimide is formed on the
whole area of the substrate 11 by, for example, spin coat method.
The planarizing layer 13 is patterned in a given shape by exposure
and development, and a contact hole 13A is formed. The planarizing
layer 13 is provided in order to planarize the surface of the
substrate 11 wherein the TFT 12 is formed, and evenly form a film
thickness in the direction of layers (hereinafter referred to as
"thickness") of respective layers of the organic light emitting
devices 10R, 10G, and 10B formed in a subsequent process. The
planarizing layer 13 is preferably made of a material having a
desirable pattern precision, since the fine contact hole 13A is
formed. As a material for the planarizing layer 13, an inorganic
material such as silicon oxide (SiO2) or the like can be used,
instead of the organic material such as polyimide or the like.
[0063] Subsequently, as shown in FIGS. 11 and 12, first electrodes
(individual electrodes) 14 are formed in the shape of a matrix on
the planarizing layer 13 corresponding to respective devices by,
for example, spattering and lithography technique. The first
electrodes 14 are connected to the wiring 12B through the contact
hole 13A. The first electrode 14 also has a function as a
reflection layer. For example, the first electrode 14 preferably
has a thickness of about 200 nm, and is made of a substance or an
alloy of a metal element having a high work function, such as
platinum (Pt), gold (Au), silver (Ag), chromium (Cr), tungsten (W)
or the like.
[0064] After that, as shown in FIGS. 13 and 14, an insulating film
15 is formed in an area between lines and columns of the first
electrodes 14 by, for example, CVD (Chemical Vapor Deposition)
method and lithography technique, and openings 15A are formed
corresponding to light emitting region. The insulating film 15 is
provided in order to secure insulation between the first electrodes
14 and a second electrode 16, which will be described later, and
accurately obtain a desired shape of light emitting region in the
organic light emitting devices 10R, 10G, and 10B. For example, the
insulating film 15 has a thickness of about 600 nm, and is made of
an insulating material such as silicon oxide, polyimide and the
like.
[0065] Next, as shown in FIGS. 15 and 16, an auxiliary electrode
16A is formed in the shape of a matrix on the insulating film 15
by, for example, spattering and lithography technique. The
auxiliary electrode 16A is provided in order to uniform a wiring
resistance between a power source (not shown) and respective light
emitting parts, and inhibit generation of emission unevenness
(particularly emission unevenness between a central part and a
peripheral part inside a picture) due to a difference of voltage
drop. For example, the auxiliary electrode 16A has a monolayer
structure or a layered structure of a conductive material having a
low resistance, such as aluminum (Al), chromium (Cr) and the like.
Further, as shown in FIGS. 15 and 16 as well, a trunk-shaped
auxiliary electrode 16B which becomes a bus line of the auxiliary
electrode 16A is formed in a peripheral area of the substrate 11
by, for example, spattering and lithography technique. The
trunk-shaped auxiliary electrode 16B is made of a material similar
to for the auxiliary electrode 16A, for example. However, since the
trunk-shaped auxiliary electrode 16B is formed in the peripheral
area of the substrate 11, its thickness and width can be made
larger than that of the auxiliary electrode 16A. That is, it is
possible to further lower a wiring resistance. The trunk-shaped
auxiliary electrode 16B and the auxiliary electrode 16A are
electrically connected by, for example, forming them so that ends
of the auxiliary electrode 16A contact with the trunk-shaped
auxiliary electrode 16B. The trunk-shaped auxiliary electrode 16B
can be either formed integrally with the auxiliary electrode 16A in
the same process, or formed in other process. In addition, the
trunk-shaped auxiliary electrode 16B can be formed on the substrate
11. In this case, electrical connection between the trunk-shaped
auxiliary electrode 16B and the auxiliary electrode 16A can be
conducted with the planarizing layer 13 in between through the
contact hole.
[0066] An extraction electrode 16C is provided at an end of the
trunk-shaped auxiliary electrode 16B in order to connect the second
electrode 16 to the power source (not shown). This extraction
electrode 16C can be made of, for example, titanium (Ti)-aluminum
(Al) or the like.
[0067] Subsequently, as shown in FIGS. 17 and 18, a green
continuous organic layer 17G common to the organic light emitting
devices 10G is formed by deposition method by using a deposition
mask 40 having stripe-shaped openings 41. As shown in FIG. 19, the
green continuous organic layer 17G having, for example, semioval
notches 17A in an area between the organic light emitting devices
10G is thereby formed.
[0068] As the green continuous organic layer 17G, for example, an
electron hole transport layer and a light emitting layer are
layered in this order from the first electrode 14 side. The
electron hole transport layer is provided in order to raise
electron hole injection efficiency to the light emitting layer. The
light emitting layer is provided in order to reconnect electrons
and electron holes and generate light by applying electric field.
Examples of the component material for the electron hole transport
layer of the green continuous organic layer 17G include .alpha.-NPD
and the like. Examples of the component material for the light
emitting layer of the green continuous organic layer 17G include
one wherein Coumarin 6 (C6) of 1 vol % is mixed with 8-quinolinol
aluminum complex (Alq3).
[0069] The deposition mask 40 shown in FIGS. 17 and 18 includes a
flat plate-shaped body part 40A made of a material having magnetic
characteristics such as nickel (Ni) and an alloy containing nickel,
and one or more, such as two, stripe-shaped openings 41. The
opening 41 is arranged and formed so that a number of devices of
the organic light emitting devices 10R, 10G, or 10B whose light
emitting color is the same can be simultaneously formed. For
example, as shown in FIGS. 17 and 18, the green continuous organic
layer 17G common to the organic light emitting devices 10G can be
formed by performing deposition by aligning the opening 41 with a
position where the organic light emitting devices 10G can be
formed. In this embodiment, the green continuous organic layer 17G
is formed for a number, such as three, of organic light emitting
devices 10G in common, differently from the conventional case,
wherein the organic layer is formed for each organic light emitting
device 10G. Therefore, generation of a film thickness distribution
in the extensional direction of the green continuous organic layer
17G is dissolved. Consequently, its light emitting region can be
expanded by just that much, and its aperture ratio can be
raised.
[0070] In this embodiment, the body part 40A includes protrusions
41A to protrude inside the opening 41. The protrusion 41A is
provided in order to provide the notch part 17A, which will be
described later, on the green continuous organic layer 17G
corresponding to an area between lines of the adjacent organic
light emitting devices 10G. The protrusions 41A are, for example,
provided as a pair at the relative positions on both sides in the
width direction of the opening 41. There are a number of pairs
(i.e., two pairs) of the protrusions 41A so that these pairs can
correspond to respective positions between lines of the organic
light emitting devices 10G.
[0071] A shape of the protrusion 41A is preferably set not to block
the opening 15A of the insulating film 15, that is a light emitting
region. If set as above, an after-mentioned contact part 18 between
the auxiliary electrode 16A and the second electrode 16 can be
provided without preventing improvement of an aperture ratio.
Concrete examples of the shape of the protrusion 41A include the
semioval shape shown in FIG. 18, a round shape such as semicircle
(not shown), a triangle as shown in FIG. 20, and a non-circular
shape such as a rectangle as shown in FIG. 21. Dimensions of the
protrusion 41A are set as appropriate by considering a plate
thickness of the deposition mask 40, position relation with the
light emitting region, dimensions of the contact part 18 and the
like. In this embodiment, dimensions of the protrusion 41A are set,
for example, as follows: a dimension in the extensional direction
of the opening 41, d1 is about 40 nm, and a dimension (width) in
the direction perpendicular to the extensional direction of the
opening 41, d2 is about 30 nm. The opening 41 and the protrusion
41A can be formed, for example, by etching or electroforming
method.
[0072] FIG. 22 shows an outline construction of a deposition
apparatus to form the green continuous organic layer 17G by using
such a deposition mask 40. This deposition apparatus 50 includes a
deposition source 52 housing an organic material, which is a
component material for the green continuous organic layer 17G
inside a vacuum chamber 51. A work 53 wherein the deposition mask
40 is attached to the substrate 11 is arranged facing to the
deposition source 52. Though unshown, a carry-in entrance and a
vent for the work 53 are provided for the vacuum chamber 51.
[0073] A construction of the deposition source 52 is not
particularly limited, and can be either a point source or a line
source. As the deposition source 52, a resistance deposition
source, an EB (Electron Beam) deposition source or the like can be
used. The deposition source 52 can be provided respectively for the
electron hole transport layer and the light emitting layer, the
components for the green continuous organic layer 17G.
[0074] The work 53 can be either rotatable at a fixed position over
the deposition source 52, or relatively movable in relation to the
deposition source 52. The deposition mask 40 is attached on the
substrate 11 on the deposition source 52 side, being held by a mask
holder 54, and fixed by a sheet magnet 55 provided on the rear side
of the substrate 11.
[0075] After the green continuous organic layer 17G is formed as
above, the deposition mask 40 is aligned with a position where the
organic light emitting devices 10R are to be formed, and a red
continuous organic layer 17R, which has the notch parts 17A and
which is common to the organic light emitting devices 10R is formed
as shown in FIG. 23. A forming method for the red continuous
organic layer 17R and a deposition apparatus used for it are
similar to in the case of the green continuous organic layer 17G of
the organic light emitting device 10G. Consequently, the notch part
17A of the green continuous organic layer 17G and the notch part
17A of the red continuous organic layer 17R are aligned, and in the
aligned area, the auxiliary electrode 16A is exposed.
[0076] As the red continuous organic layer 17R, for example, an
electron hole transport layer, a light emitting layer, and an
electron transport layer are layered in this order from the first
electrode 14 side. The electron transport layer is provided in
order to raise electron injection efficiency to the light emitting
layer. As a component material for the electron hole transport
layer of the red continuous organic layer 17R, for example,
bis[(N-naphthyl)-N-phenyl] benzidine (.alpha.-NPD) can be employed.
As a component material for the light emitting layer of the red
continuous organic layer 17R, for example, 2,5-bis[4-[N-(4-methoxy
phenyl)-N-phenyl amino]]styryl benzene-1,4-dicarbonitrile (BSB) can
be employed. As a component material for the electron transport
layer of the red continuous organic layer 17R, for example, Alq3
can be employed.
[0077] Subsequently, the deposition mask 40 is moved again, and a
blue continuous organic layer 17B which has the notch parts 17A and
which is common to the organic light emitting devices 10B is formed
as shown in FIGS. 24, 25, and 26. A method for forming the blue
continuous organic layer 17B and a deposition apparatus used for it
are similar to in the case of the green continuous organic layer
17G of the organic light emitting device 10G. Consequently, the
notch part 17A of the blue continuous organic layer 17B and the
notch part 17A of the green continuous organic layer 17G are
aligned, and in the aligned area, the auxiliary electrode 16A is
exposed. Further, the notch part 17A of the blue continuous organic
layer 17B and the notch part 17A of the red continuous organic
layer 17R are aligned, and in the aligned area, the auxiliary
electrode 16A is exposed.
[0078] As the blue continuous organic layer 17B, for example, an
electron hole transport layer, a light emitting layer, and an
electron transport layer are layered in this order from the first
electrode 14 side. As a component material for the electron hole
transport layer of the blue continuous organic layer 17B, for
example, .alpha.-NPD can be employed. As a component material for
the light emitting layer of the blue continuous organic layer 17B,
for example, 4,4'-bis (2,2'-diphenyl vinyl)biphenyl (DPVBi) can be
employed. As a component material for the electron transport layer
of the blue continuous organic layer 17B, for example, Alq3 can be
employed.
[0079] After the red continuous organic layer 17R, the green
continuous organic layer 17G, and the blue continuous organic layer
17B are formed, as shown in FIGS. 27, 28, and 29, the second
electrode 16 covering almost a whole area of the substrate 11 is
formed by, for example, deposition method. The second electrode 16
includes a semi-transparent electrode, and light generated in the
light emitting layer is extracted from the second electrode 16
side. For example, the second electrode 16 has a thickness of about
10 nm, and made of metal such as silver (Ag), aluminum (Al),
magnesium (Mg), calcium (Ca), and sodium (Na), the like or an alloy
thereof. In this embodiment, for example, the second electrode 16
includes an alloy (MgAg alloy) of magnesium (Mg) and silver.
[0080] By forming the second electrode 16 to cover almost the whole
area of the substrate 11, the contact part 18 between the auxiliary
electrode 16A and the second electrode 16 is formed at the notch
part 17A, and the auxiliary electrode 16A and the second electrode
16 are electrically connected. Further, the second electrode 16 is
formed to cover at least part of the trunk-shaped auxiliary
electrode 16B, so that the second electrode 16 and the trunk-shaped
auxiliary electrode 16B are electrically connected. The organic
light emitting devices 10R, 10G, and 10B are thereby formed.
[0081] Next, as shown in FIG. 30, a protective film 19 is formed on
the second electrode 16 by, for example, deposition method, CVD
method, spattering or the like. For example, the protective film 19
has a thickness from about 500 nm to about 10,000 nm, and includes
a transparent dielectric such as silicon oxide (SiO2), silicon
nitride (SiN) and the like.
[0082] As shown in FIG. 31A, for example, on a sealing substrate 21
made of a material such as glass transparent to light generated in
the organic light emitting devices 10R, 10G, and 10B, a red filter
22R is formed by applying a material for the red filter 22R by spin
coat or the like by patterning with photolithography technique and
by firing. Subsequently, as shown in FIG. 31B, a blue filter 22B
and a green filter 22G are sequentially formed in a manner similar
to in the red filter 22R. A color filter 22 is thereby formed on
the sealing substrate 21. The color filter 22 is provided in order
to extract light generated in the organic light emitting devices
10R, 10G, and 10B, absorb outside light reflected in the organic
light emitting devices 10R, 10G, and 10B, and the wiring
therebetween, and improve the contrast.
[0083] After that, as shown in FIG. 32, an adhesive layer 30 made
of, for example, a thermosetting resin is formed by coating on the
side where the organic light emitting devices 10R, 10G, and 10B are
formed of the substrate 11. Coating can be made by, for example,
discharging a resin from a slit nozzle type dispenser, roll
coating, or screen printing. Next, as shown in FIG. 33, the
substrate 11 and the sealing substrate 21 are bonded together with
the adhesive layer 30 in between. In this regard, it is preferable
that a side of the sealing substrate 21 where the color filter 22
is formed is arranged facing to the substrate 11. It is preferable
that air bubbles or the like does not enter into the adhesive layer
30. After that, relative positions of the color filter 22 of the
sealing substrate 21 and the organic light emitting devices 10R,
10G, and 10B of the substrate 11 are aligned. Then, the
thermosetting resin of the adhesive layer 30 is cured by heat
treatment for a given time at a given temperature. The display unit
according to this embodiment is thereby completed.
[0084] In the display unit manufactured as above, when a given
voltage is applied between the first electrodes 14 and the second
electrode 16, current is injected in the light emitting layer of
the continuous organic layer 17, electron holes and electrons are
recombined. Consequently, light emitting is generated. This light
is extracted from the sealing substrate 21 side. In this case, the
red continuous organic layer 17R is provided for the number of
(three in FIG. 19) organic light emitting devices 10R in common,
the green continuous organic layer 17 G is provided for the number
of organic light emitting devices 10G in common, and the blue
continuous organic layer 17B is provided for the number of organic
light emitting devices 10B in common, respectively. Therefore,
differently from the conventional case of forming the organic
layers corresponding to respective organic light emitting devices,
each device is free from or without a film thickness distribution
in the extensional direction of the red continuous organic layer
17R and so on, and has an even thickness.
[0085] Further, the notch parts 17A are provided at a position
corresponding to a non-light emitting region (that is, an area
between lines of the matrix configuration) of the red continuous
organic layer 17R, the green continuous organic layer 17G, and the
blue continuous organic layer 17B. Therefore, the contact part 18
between the second electrode 16 and the auxiliary electrode 16A is
formed for each device without lowering the aperture ratio.
[0086] FIG. 34 shows an equivalent circuit diagram of a connection
circuit part between respective devices and the extraction
electrode 16C. Since the second electrode 16 includes a thin film
common electrode, a resistance component R1 between the extraction
electrode 16C and the device closest to the extraction electrode
16C, and resistance components R2 and R3 between devices are high,
and voltage drop varies depending on differences of distance
between respective devices and the extraction electrode 16C,
causing luminance variation between the central part and the
peripheral part in the display screen. In this embodiment, the
second electrode 16 is electrically connected to the auxiliary
electrode 16A through the contact part 18 at the position
corresponding to respective devices. The auxiliary electrode 16A
has a thick film thickness, and a resistance component R4 between
the extraction electrode 16C and the device closest to the
extraction electrode 16C, and resistance components R5 and R6
between devices are relatively small compared to resistance
components R1 to R3. That is, in a route from the extraction
electrode 16C to respective devices through the auxiliary electrode
16A and the contact part 18, wiring resistance differences between
the extraction electrode 16C and respective devices are reduced and
uniformed. Therefore, current sent from the power source (not
shown) and supplied through the electrode 16C is applied to
respective devices through the auxiliary electrodes 16A and the
contact part 18 without raising any large difference in voltage
drop. Consequently, display is realized with an even luminance over
the whole screen.
[0087] As above, in this embodiment, the red continuous organic
layer 17R, the green continuous organic layer 17G, and the blue
continuous organic layer 17B are provided for the number of organic
light emitting devices 10R, 10G, and 10B in common, respectively.
Therefore, a film thickness distribution is dissolved in the
extensional direction of the red continuous organic layer 17R, the
green continuous organic layer 17G, and the blue continuous organic
layer 17B, and an aperture ratio can be improved by just that much.
Further, the contact part 18 between the second electrode 16 and
the auxiliary electrode 16A is formed at the notch parts 17A formed
in the non-light emitting region of respective continuous organic
layers. Therefore, the contact part 18 can be formed corresponding
to respective devices inside the panel, and wiring resistance
differences between the extraction electrode 18C and respective
devices can be reduced and uniformed. Consequently, luminance
variation between the center and the peripheral part in the display
screen can be remedied.
[0088] While the invention has been described with reference to the
embodiment, the invention is not limited to the foregoing
embodiment, and various modifications may be made. For example, in
the foregoing embodiment, the case wherein the protrusions 41A are
provided so that these protrusions 41A make a pair at the relative
positions on the both sides in the width direction of the opening
41, and the notch parts 17A are positioned adjacent to each other
has been described. However, as shown in FIG. 35, it is possible
that a long protrusion 41C is provided in the width direction only
at one side in the width direction of the opening 41, and the
contact part 18 is formed without positioning the notch parts 17A
adjacent to each other. However, the foregoing embodiment is
preferable, since it is possible to surely obtain the effect to
improve an aperture ratio by reducing a film thickness distribution
in the extensional direction of the red continuous organic layer
17R, the green continuous organic layer 17G, and the blue
continuous organic layer 17B. When the protrusion 41C is provided
only at one side in the width direction of the opening 41, it is
not always necessary to provide the protrusions 41 only at the same
side in the width direction of the opening 41.
[0089] In the foregoing embodiment, the case wherein the organic
light emitting devices 10R, 10G, and 10B are respectively arranged
in line, and the red continuous organic layer 17R, the green
continuous organic layer 17G, and the blue continuous organic layer
17B are formed in the shape of a straight stripe has been
described. However, it is no problem as long as the red continuous
organic layer 17R, the green continuous organic layer 17G, and the
blue continuous organic layer 17B are formed for two or more lines
of the organic light emitting devices 10R, 10G, and 10B in common.
It is not necessarily that the organic light emitting devices 10R,
10G, and 10B are respectively arranged in line. For example, it is
possible that the organic light emitting devices 10R, 10G, and 10B
are arranged in the staggered shape.
[0090] In the foregoing embodiment, the case wherein the auxiliary
electrode 16A is formed in the shape of a matrix in the area
between lines and columns of the first electrodes 14 on the
insulating film 15 has been described. However, the auxiliary
electrode 16A can be provided only in the area between lines of the
first electrodes 14, or only in the area between columns of the
first electrodes 14.
[0091] The materials, thicknesses, deposition methods, deposition
conditions and the like of respective layers are not limited to
those described in the foregoing embodiment. Other materials,
thicknesses, deposition methods, and deposition conditions can be
applied. For example, film-forming order of the red continuous
organic layer 17R, the green continuous organic layer 17G, and the
blue continuous organic layer 17B is not limited to the order
described in the foregoing embodiment.
[0092] For example, in the foregoing embodiment, the case wherein
the first electrodes 14, the continuous organic layer 17, and the
second electrode 16 are layered in this order from the substrate 11
side, and light is extracted from the sealing substrate 21 side has
been described. However, light can be extracted from the substrate
11 side. However, in the foregoing embodiment, the TFTs 12 are
provided on the substrate 11 corresponding to the respective
organic light emitting devices 10R, 10G and 10B, and the organic
light emitting devices 10R, 10G and 10B are driven by these TFTs
12. Therefore, it is more beneficial to extract light from the
sealing substrate 21 side wherein no TFTs 12 are provided, since an
aperture ratio becomes large and effect of the invention can be
further improved.
[0093] For example, in the foregoing embodiment, the case wherein
the first electrode 14 is set to an anode and the second electrode
16 is set to a cathode. However, it is possible that the anode and
the cathode are inversed, that is, the first electrode 14 can be
set to a cathode and the second electrode 16 can be set to an
anode. Further, along with setting the first electrode 14 to the
cathode and the second electrode 16 to the anode, it is possible to
extract light from the substrate 11 side.
[0094] In the foregoing embodiment, the concrete example of the
construction of the organic light emitting devices 10R, 10G, and
10B has been described. However, it is not necessary that all
layers are provided. In addition, other layers can be further
provided. Layer constructions and component materials for the red
continuous organic layer 17R, the green continuous organic layer
17G, and the blue continuous organic layer 17B of the organic light
emitting devices 10R, 10G, and 10B are not limited to the case in
the foregoing embodiment.
[0095] In the foregoing embodiment, the case wherein the invention
is applied to the color display has been described. However, the
invention can be applied to the case of a mono-color display.
[0096] As described above, according to the deposition mask of the
invention and the method for manufacturing the display unit of the
invention, the continuous organic layer common to at least two
lines of the matrix configuration of the number of organic light
emitting devices is formed through the stripe-shaped opening
provided on the body part of the deposition mask. Therefore, a film
thickness distribution in the extensional direction of the
continuous organic layer can be dissolved, and an aperture ratio
can be improved by just that much. Further, in the deposition mask,
the protrusions are provided to partly protrude inside the opening.
Therefore, the notch parts to become the contact part between the
auxiliary electrode and the second electrode (common electrode) can
be formed on the continuous organic layer, and wiring resistance
differences between the power source and respective devices can be
reduced and uniformed. Consequently, a luminance variation between
the center and the peripheral part of the display screen can be
improved.
[0097] According to the display unit of the invention, the
auxiliary electrode and the second electrode are electrically
connected through the contact part formed at the notch parts of the
continuous organic layer. Therefore, current supplied from the
power source can be applied to respective devices through the
auxiliary electrode and the contact part without generating large
difference in voltage drop. Consequently, a luminance variation
between the center and the peripheral part of the display screen
can be improved, and display can be realized with even luminance
over the whole area of the screen.
[0098] It should be understood that various changes and
modifications to the presently preferred embodiments described
herein will be apparent to those skilled in the art. Such changes
and modifications can be made without departing from the spirit and
scope of the present invention and without diminishing its intended
advantages. It is therefore intended that such changes and
modifications be covered by the appended claims.
* * * * *