U.S. patent application number 10/213853 was filed with the patent office on 2004-02-19 for oled apparatus including a series of oled devices.
This patent application is currently assigned to Eastman Kodak Company. Invention is credited to Tyan, Yuan-Sheng.
Application Number | 20040031957 10/213853 |
Document ID | / |
Family ID | 30443711 |
Filed Date | 2004-02-19 |
United States Patent
Application |
20040031957 |
Kind Code |
A1 |
Tyan, Yuan-Sheng |
February 19, 2004 |
OLED APPARATUS INCLUDING A SERIES OF OLED DEVICES
Abstract
An OLED apparatus including a substrate, a plurality of spaced
apart bottom electrodes disposed over the substrate; a plurality of
spaced apart organic EL elements disposed over the spaced apart
bottom electrodes and each one of the spaced apart organic EL
elements extending over an edge of its corresponding spaced apart
bottom electrode; and a plurality of spaced apart top electrodes
with each spaced apart top electrode disposed over a substantial
portion of its corresponding spaced apart organic EL element
forming a device and extending into electrical contact with the
next adjacent spaced apart bottom electrode so that current flows
between each corresponding spaced apart bottom and top electrodes
through the corresponding spaced apart organic EL element into the
next spaced apart bottom and top electrodes and spaced apart
organic EL elements so that a series connection of devices is
provided which reduces power loss due to series resistance.
Inventors: |
Tyan, Yuan-Sheng; (Webster,
NY) |
Correspondence
Address: |
Thomas H. Close
Eastman Kodak Company
Patent Legal Staff
343 State Street
Rochester
NY
14650-2201
US
|
Assignee: |
Eastman Kodak Company
|
Family ID: |
30443711 |
Appl. No.: |
10/213853 |
Filed: |
August 7, 2002 |
Current U.S.
Class: |
257/40 |
Current CPC
Class: |
H01L 27/3209 20130101;
H01L 27/3283 20130101; H01L 27/3204 20130101; H01L 27/3202
20130101 |
Class at
Publication: |
257/40 |
International
Class: |
H01L 035/24 |
Claims
What is claimed is:
1. An OLED apparatus comprising: (a) a substrate; (b) a plurality
of OLED devices including spaced apart bottom electrodes disposed
over the substrate; (c) each one of the spaced apart OLED devices
including at least one organic layer extending over an edge of its
corresponding spaced apart bottom electrode; and (d) each one of
the plurality of OLED devices including a top electrode spaced
apart from the other top electrodes and extending into electrical
contact with the spaced apart bottom electrode of a neighboring
OLED device so that a series connection of OLED devices is provided
and current flows between the spaced apart top and bottom
electrodes of each OLED device and from the spaced apart bottom
electrode of such OLED device to the spaced apart top electrode of
the next OLED device which reduces power loss due to series
resistance.
2. The OLED apparatus of claim 1 wherein at least one organic layer
of each OLED device terminates in the space between adjacent spaced
apart bottom electrodes or extends into contact with the next
adjacent spaced apart bottom electrode.
3. The OLED apparatus of claim 2 wherein the spaced apart bottom
electrodes are anodes and the spaced apart top electrodes are
cathodes.
4. The OLED apparatus of claim 1 further including a plurality of
spaced apart pillar structures each disposed on one spaced apart
bottom electrode to provide the function of a shadow mask which
permits the patterned deposition of the spaced apart organic layers
and the spaced apart top electrodes and wherein each spaced apart
top electrode is in contact with its next adjacent spaced apart
bottom electrode to form the series connection.
5. An array of OLED apparatus on a common substrate which are
electrically insulated from each other and wherein each OLED
apparatus is in accordance with claim 1.
6. The array of OLED apparatus of claim 5 wherein the top
electrodes of the first OLED devices in each OLED apparatus are
electrically connected and wherein the bottom electrodes of the
last OLED devices of each OLED apparatus are electrically
connected.
7. The array of OLED apparatus of claim 5 wherein each OLED device
of the array emits colored light.
8. The array of OLED apparatus of claim 7 wherein the colored light
is red, green or blue.
9. The array of OLED apparatus of claim 7 wherein each OLED device
of the array emits colored light so as to form a repeating pattern
of red, green and blue.
10. The array of OLED apparatus of claim 5 wherein each OLED
apparatus emits a single colored light so as to form a repeating
pattern of different colored light and further including means for
electrically connecting the bottom electrodes of the first OLED
devices of all OLED apparatus that produce the same color and the
top electrodes of the last OLED devices of all OLED apparatus that
produce the same color are electrically connected.
11. The array of claim 10 further including means for controlling
the current flow through the electrodes of the OLED apparatus to
adjust the color of light produced by the array.
12. A method of making an OLED apparatus comprising the steps of:
(a) forming a substrate; and (b) forming a plurality of OLED
devices including spaced apart bottom electrodes disposed over the
substrate, each one of the spaced apart OLED devices including at
least one organic layer extending over an edge of its corresponding
spaced apart bottom electrode, each one of the plurality of OLED
devices including a top electrode spaced apart from the other top
electrodes and extending into electrical contact with the spaced
apart bottom electrode of a neighboring OLED device so that a
series connection of OLED devices is provided and current flows
between the spaced apart top and bottom electrodes of each OLED
device and from the spaced apart bottom electrode of such OLED
device to the spaced apart top electrode of the next OLED device
which reduces power loss due to series resistance.
13. An OLED apparatus comprising: (a) a substrate; (b) a plurality
of stacked OLED devices disposed over the substrate wherein each
one of the plurality of stacked OLED devices including a spaced
apart top electrode, a spaced apart bottom electrode, and a
plurality of individual light emitting devices stacked in between
the spaced apart top electrode and the spaced apart bottom
electrode; (c) each one of the plurality of stacked OLED devices
further including doped organic connector disposed between
neighboring individual light emitting devices; (d) each one of the
plurality of stacked OLED devices further including at least one
organic layer disposed over one edge of the spaced apart bottom
electrode of the same stacked OLED device; (e) the spaced apart top
electrode of each one of the plurality of stacked OLED devices
extending beyond the said one edge of the spaced apart organic
layer of the same stacked OLED device and making electrical contact
with the spaced apart bottom electrode of the next stacked OLED
device so that the plurality of stacked OLED devices are connected
in series.
14. The OLED apparatus of claim 13 wherein at least one organic
layer of each OLED device terminates in the space between adjacent
spaced apart bottom electrodes or extends into contact with the
next adjacent spaced apart bottom electrode.
15. The OLED apparatus of claim 13 wherein the spaced apart bottom
electrodes are anodes and the spaced apart top electrodes are
cathodes.
16. The OLED apparatus of claim 13 further including a plurality of
spaced apart pillar structures each disposed on one spaced apart
bottom electrode to provide the function of a shadow mask which
permits the patterned deposition of the spaced apart organic layers
and the spaced apart top electrodes and wherein each spaced apart
top electrode is in contact with its next adjacent spaced apart
bottom electrode to form the series connection.
17. An array of OLED apparatus on a common substrate which are
electrically insulated from each other and wherein each OLED
apparatus is in accordance with claim 13.
18. The array of OLED apparatus of claim 17 wherein the top
electrodes of the first OLED devices in each OLED apparatus are
electrically connected and wherein the bottom electrodes of the
last OLED devices of each OLED apparatus are electrically
connected.
19. The array of OLED apparatus of claim 17 wherein each OLED
device of the array emits colored light.
20. The array of OLED apparatus of claim 19 wherein the colored
light is red, green or blue.
21. The array of OLED apparatus of claim 19 wherein each OLED
device of the array emits colored light so as to form a repeating
pattern of red, green and blue.
22. The array of OLED apparatus of claim 17 wherein each OLED
apparatus emits a single colored light so as to form a repeating
pattern of different colored light and further including means for
electrically connecting the bottom electrodes of the first OLED
devices of all OLED apparatus that produce the same color and the
top electrodes of the last OLED devices of all OLED apparatus that
produce the same color are electrically connected.
23. The array of claim 22 further including means for controlling
the current flow through the electrodes of the OLED apparatus to
adjust the color of light produced by the array.
24. A method of making an OLED apparatus comprising the steps of:
(a) forming a substrate; and (b) forming a plurality of stacked
OLED devices including spaced apart bottom electrodes disposed over
the substrate, each one of the spaced apart OLED devices including
at least one organic layer extending over an edge of its
corresponding spaced apart bottom electrode, each one of the
plurality of OLED devices including a top electrode spaced apart
from the other top electrodes and extending into electrical contact
with the spaced apart bottom electrode of a neighboring OLED device
so that a series connection of OLED devices is provided and current
flows between the spaced apart top and bottom electrodes of each
OLED device and from the spaced apart bottom electrode of such OLED
device to the spaced apart top electrode of the next OLED device
which reduces power loss due to series resistance.
25. An OLED apparatus comprising: (a) a substrate; (b) a plurality
of stacked OLED devices disposed over the substrate wherein each
one of the plurality of stacked OLED devices including a spaced
apart top electrode, a spaced apart bottom electrode, and a
plurality of individual light emitting devices stacked in between
the spaced apart top electrode and the spaced apart bottom
electrode (c) each one of the plurality of stacked OLED devices
further including inter-device electrodes disposed between
neighboring individual light emitting devices, (d) each one of the
plurality of stacked OLED devices further including at least one
organic layer disposed over one edge of the spaced apart bottom
electrode of the same stacked OLED device, (e) the spaced apart top
electrode of each one of the plurality of stacked OLED devices
extending beyond the said one edge of the spaced apart organic
layer of the same stacked OLED device and making electrical contact
with the spaced apart bottom electrode of the next stacked OLED
device so that the plurality of stacked OLED devices are connected
in series.
26. The OLED apparatus of claim 25 wherein at least one organic
layer of each OLED device terminates in the space between adjacent
spaced apart bottom electrodes or extends into contact with the
next adjacent spaced apart bottom electrode.
27. The OLED apparatus of claim 25 wherein the spaced apart bottom
electrodes are anodes and the spaced apart top electrodes are
cathodes.
28. The OLED apparatus of claim 25 further including a plurality of
spaced apart pillar structures each disposed on one spaced apart
bottom electrode to provide the function of a shadow mask which
permits the patterned deposition of the spaced apart organic layers
and the spaced apart top electrodes and wherein each spaced apart
top electrode is in contact with its next adjacent spaced apart
bottom electrode to form the series connection.
29. An array of OLED apparatus on a common substrate which are
electrically insulated from each other and wherein each OLED
apparatus is in accordance with claim 1.
30. The array of OLED apparatus of claim 29 wherein the top
electrodes of the first OLED devices in each OLED apparatus are
electrically connected and wherein the bottom electrodes of the
last OLED devices of each OLED apparatus are electrically
connected.
31. The array of OLED apparatus of claim 29 wherein each OLED
device of the array emits colored light.
32. The array of OLED apparatus of claim 31 wherein the colored
light is red, green or blue.
33. The array of OLED apparatus of claim 31 wherein each OLED
device of the array emits colored light so as to form a repeating
pattern of red, green and blue.
34. The array of OLED apparatus of claim 29 wherein each OLED
apparatus emits a single colored light so as to form a repeating
pattern of different colored light and further including means for
electrically connecting the bottom electrodes of the first OLED
devices of all OLED apparatus that produce the same color and the
top electrodes of the last OLED devices of all OLED apparatus that
produce the same color are electrically connected.
35. The array of OLED apparatus of claim 28 wherein at least one
organic layer of each OLED device terminates in the space between
adjacent spaced apart bottom electrodes or extends into contact
with the next adjacent spaced apart bottom electrode.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Reference is made to commonly assigned U.S. patent
application Ser. No. ______ filed concurrently herewith, entitled
"Serially Connecting OLED Devices for Area Illumination" by Ronald
S. Cok et al, and U.S. patent application Ser. No. 10/077,270 filed
Feb. 15, 2002 entitled "Providing an Organic Electroluminescent
Device Having Stacked Electroluminescent Units" by Liang-Sheng L.
Liao et al. the disclosures of which are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] This invention relates to large area organic light emitting
device (OLED) and to methods to reduce power consumption due to
series resistance and to methods to reduce detrimental impact due
to shorting defects.
BACKGROUND OF THE INVENTION
[0003] Organic light emitting devices (OLED) generally can have two
formats known as small molecule devices such as disclosed in
commonly-assigned U.S. Pat. No. 4,476,292 and polymer OLED devices
such as disclosed in U.S. Pat. No. 5,247,190. Either type of OLED
device is typically a thin film structure comprising an organic EL
element sandwiched between a cathode layer and an anode layer
formed on a substrate such as soda-lime glass. The organic EL
element can actually be constructed of several layers including a
hole-injecting layer, a hole-transporting layer, a light-emitting
layer, an electron-transporting layers, and an electron-injecting
layer. Not all these layers, with the exception of the
light-emitting layer, need to be present in a particular OLED
device; on the other hand there may be additional functional layers
in the device as well. The light-emitting layer may be selected
from any of a multitude of fluorescent or phosphorescent organic
materials. The light emitting-layer may also include multiple
sub-layers. When a potential difference is applied between the
anode and the cathode, negatively charged electrons move from the
cathode layer into the OLED device. At the same time, positive
charges, typically referred to as holes, move from the anode layer
into the OLED device. When the positive and negative charges meet,
they recombine and produce photons. The wavelength, and
consequently the color, of the photons depend on the electronic
properties of the organic material in which the photons are
generated. In an OLED device either the cathode layer or the anode
layer is transparent to the photons generated, allowing the light
to emit from the device to the outside world.
[0004] An OLED device can also have a stacked structure as taught
in U.S. Pat. No. 6,337,492. The OLED device having a stacked
structure (a stacked OLED device) comprises a top electrode, a
bottom electrode, and a plurality of individual light emitting
devices vertically stacked between the top electrode and the bottom
electrode. A pair of inter-device electrodes are also provided
between the neighboring individual light emitting devices. These
inter-device electrodes are to inject electrons and holes,
respectively, to the individual light emitting devices above and
below them, and to electrically connect these two individual light
emitting devices. The individual light emitting devices in the
stack are thereby connected in series. In operation, electricity is
applied between the top electrode and the bottom electrode. The
same current flows through all the individual light emitting
devices in the stack and the applied voltage is divided among all
the individual light emitting devices in the stack. The
inter-device electrodes are commonly 0.1 to 15 nm thick, and
include allegedly transparent metal alloys, metal oxides, and other
well known inorganic electrode materials commonly used in OLED
devices.
[0005] The OLED devices are low voltage, high current devices. A
typical device operates at 3-10 volts of voltage and has about 1 to
10 Cd/A of light-generating efficiency. For many display or
lighting applications, a brightness of about 1000 Cd/m.sup.2 is
requred. The operating current, therefore, has to be about 100
A/m.sup.2 to 1000 A/m.sup.2. These characteristics are ideal for
small devices such as those for portable applications that require
device areas less than about 0.01 m.sup.2. When device area
increases, however, these characteristics lead to practical
problems. For example, some lighting applications may require
devices with area as large as 1 m.sup.2. The operating current in
these devices can be as high as 100 A to 1000 A. Since the anode
and cathode layers are thin-films having limited electrical
conductivity, they are not able to carry these high currents
without substantial energy loss due to series resistance. This
problem is accentuated since one of the electrode layers also has
to be optically transparent to allow emitted light to get through.
If a stacked OLED device is used, the situation is somewhat
improved. If a stacked OLED and a non-stacked OLED device are
operated at the same light output level, the operating current of
the stacked OLED device equals I/N where I is the current of the
non-stacked OLED device and N is the number of individual light
emitting elements in the stacked OLED device. The lowered operating
current results in lowered power loss due to series resistance.
However, since the total number of cells in the stack is limited by
practical factors, A stacked OLD device is still a relative low
voltage, high current device and the energy loss due to series
resistance is still a serious problem.
[0006] Another common problem encountered in making large area OLED
devices is failure due to shorting defects. Since OLED devices use
very thin layers, pinholes, dust particles, and many other kinds of
defects can cause shorting between the anode and the cathode.
Applied electricity will go through the shorting defect instead of
the light-emitting device. A single shorting defect can cause an
entire OLED device to fail. Even with the best efforts practiced in
manufacturing, it is difficult to eliminate all shorting defects in
large area thin-film electrical devices. Assuming the defects are
randomly distributed, the probability of finding X defects in a
device of area A with a defect density of N.sub.d can be expressed
by
P(X, A, N.sub.d)=[(A.multidot.N.sub.d).sup.x
exp(-A.multidot.N.sub.d)]/X!
[0007] Thus the probability of having a defect free device of area
A is
P(0, A, N.sub.d)=exp(-A.multidot.N.sub.d).
[0008] The probability decreases exponentially with increasing
area. For example, even if the defect density is as low as
0.001/cm.sup.2, the probability of having a defect free 1 m.sup.2
device is only 36.8%. Thus for making large area OLED devices
practical, it is imperative to find solution to the shorting defect
problem.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the present invention to
provide an improved large-area OLED apparatus with reduced
detrimental impacts due to series resistance and shorting
defects.
[0010] This object is achieved by providing an OLED apparatus
comprising:
[0011] (a) a substrate;
[0012] (b) a plurality of OLED devices including spaced apart
bottom electrodes disposed over the substrate;
[0013] (c) each one of the plurality of OLED devices including at
least one organic layer extending over an edge of its corresponding
spaced apart bottom electrode; and
[0014] (d) each one of the plurality of OLED devices including a
top electrode spaced apart from the top electrodes of other OLED
devices and extending into electrical contact with the spaced apart
bottom electrode of a neighboring OLED device so that a series
connection of OLED devices is provided and current flows between
the spaced apart top and bottom electrodes of each OLED device and
from the spaced apart bottom electrode of such OLED device to the
spaced apart top electrode of the next OLED device which reduces
power loss due to series resistance.
[0015] An advantage of the present invention is a reduced energy
loss due to series resistance. Another advantage of apparatus made
in accordance with this invention is a reduced impact due to
shorting defects. A further advantage of the apparatus made in
accordance with this invention is that it can be designed to have
tunable color. Another further advantage of the apparatus is that
it can use stacked cells to further improve its performance. A
still further advantage of the present invention is that the
apparatus can be manufactured at low cost. The present invention is
particularly suitable for forming large-area OLED apparatus.
[0016] Additional objects and advantages of the invention are set
forth, in part, in the description which follows, and, in part,
will be apparent to one of ordinary skill in the art from the
description and/or from the practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic illustration of the cross section of a
conventional OLED device;
[0018] FIG. 2 is a schematic illustration of the cross section of a
conventional OLED device wherein the organic EL element includes
several layers;
[0019] FIG. 3 is a schematic illustration of the cross section of
an OLED apparatus according to the present invention;
[0020] FIG. 4 is a schematic illustration of the cross section of
an OLED apparatus according to the present invention comprising
stacked cells;
[0021] FIG. 4a is a schematic illustration of the cross section of
an OLED apparatus according to the present invention comprising
stacked cells;
[0022] FIG. 5 is a schematic illustration of the top-view of an
OLED apparatus according to the present invention;
[0023] FIG. 6 is a schematic illustration of an array of
electrically isolated OLED apparatus according to the current
invention on a common substrate; and
[0024] FIG. 7 is a schematic illustration of the cross section of
an OLED apparatus according to the present invention using a
built-in pillar structure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] FIG. 1 is a schematic illustration of the cross section of a
typical OLED device 100 including a substrate 10, an anode layer
12, an organic EL element 14, and a cathode layer 16. There are
numerous configurations of the organic EL element 14 wherein the
present invention can be successfully practiced. A typical
structure 200 is shown in FIG. 2 and is comprised of a substrate
10, an anode layer 12, an organic EL element 14 and a cathode layer
16, wherein organic EL element 14 includes an hole-injecting layer
13, a hole-transporting layer 15, a light-emitting layer 17, and an
electron-transporting layer 19. The total combined thickness of EL
organic element 14 is preferably less than 500 nm. These layers are
described in detail below. Note that the substrate may
alternatively be located adjacent to the cathode, or the substrate
may actually constitute the anode or cathode.
[0026] Substrate
[0027] The OLED apparatus of this invention is typically provided
over a supporting substrate where either the cathode or anode can
be in contact with the substrate. The electrode in contact with the
substrate is conveniently referred to as the bottom electrode.
Conventionally, the bottom electrode is the anode, but this
invention is not limited to that configuration. The substrate can
either be light transmissive or opaque, depending on the intended
direction of light emission. The light transmissive property is
desirable for viewing the EL emission through the substrate.
Transparent glass or plastic is commonly employed in such cases.
For applications where the EL emission is viewed through the top
electrode, the transmissive characteristic of the bottom support is
immaterial, and therefore can be light transmissive, light
absorbing or light reflective. Substrates for use in this case
include, but are not limited to, glass, plastic, semiconductor
materials, silicon, ceramics, and circuit board materials. Of
course it is necessary to provide in these device configurations a
light-transparent top electrode.
[0028] Anode
[0029] When EL emission is viewed through anode 12, the anode
should be transparent or substantially transparent to the emission
of interest. Common transparent anode materials used in this
invention are indium-tin oxide (ITO), indium-zinc oxide (IZO) and
tin oxide, but other metal oxides can work including, but not
limited to, aluminum- or indium-doped zinc oxide, magnesium-indium
oxide, and nickel-tungsten oxide. In addition to these oxides,
metal nitrides, such as gallium nitride, and metal selenides, such
as zinc selenide, and metal sulfides, such as zinc sulfide, can be
used as the anode. For applications where EL emission is viewed
only through the cathode electrode, the transmissive
characteristics of anode are immaterial and any conductive material
can be used, transparent, opaque or reflective. Example conductors
for this application include, but are not limited to, gold,
iridium, molybdenum, palladium, and platinum. Typical anode
materials, transmissive or otherwise, have a work function of 4.1
eV or greater. Desired anode materials are commonly deposited by
any suitable means such as evaporation, sputtering, chemical vapor
deposition, or electrochemical means. Anodes can be patterned using
well-known photolithographic processes or by using shadow masks
during preparation.
[0030] Hole-Injecting Layer (HIL)
[0031] It is often useful to provide a hole-injecting layer 13 be
provided between anode 12 and hole-transporting layer 15. The
hole-injecting material can serve to improve the film formation
property of subsequent organic layers and to facilitate injection
of holes into the hole-transporting layer. Suitable materials for
use in the hole-injecting layer include, but are not limited to,
porphyrinic compounds as described in commonly-assigned U.S. Pat.
No. 4,720,432, and plasma-deposited fluorocarbon polymers as
described in commonly-assigned U.S. Pat. No. 6,208,075. Alternative
hole-injecting materials reportedly useful in organic EL devices
are described in EP 0 891 121 A1 and EP 1 029 909 A1.
[0032] Hole-Transporting Layer (HTL)
[0033] The hole-transporting layer 15 contains at least one
hole-transporting compound such as an aromatic tertiary amine,
where the latter is understood to be a compound containing at least
one trivalent nitrogen atom that is bonded only to carbon atoms, at
least one of which is a member of an aromatic ring. In one form the
aromatic tertiary amine can be an arylamine, such as a
monoarylamine, diarylamine, triarylamine, or a polymeric arylamine.
Exemplary monomeric triarylamines are illustrated by Klupfel et al.
U.S. Pat. No. 3,180,730. Other suitable triarylamines substituted
with one or more vinyl radicals and/or comprising at least one
active hydrogen containing group are disclosed by Brantley et al in
commonly-assigned U.S. Pat. Nos. 3,567,450 and 3,658,520.
[0034] A more preferred class of aromatic tertiary amines are those
which include at least two aromatic tertiary amine moieties as
described in commonly-assigned U.S. Pat. Nos. 4,720,432 and
5,061,569. The hole-transporting layer can be formed of a single or
a mixture of aromatic tertiary amine compounds. Illustrative of
useful aromatic tertiary amines are the following:
[0035] 1,1-Bis(4-di-p-tolylaminophenyl)cyclohexane
[0036] 1,1-Bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane
[0037] 4,4'-Bis(diphenylamino)quadriphenyl
[0038] Bis(4-dimethylamino-2-methylphenyl)-phenylmethane
[0039] N,N,N-Tri(p-tolyl)amine
[0040]
4-(di-p-tolylamino)-4'-[4(di-p-tolylamino)-styryl]stilbene
[0041] N,N,N',N'-Tetra-p-tolyl-4-4'-diaminobiphenyl
[0042] N,N,N',N'-Tetraphenyl-4,4'-diaminobiphenyl
[0043] N,N,N',N'-tetra-1-naphthyl-4,4'-diaminobiphenyl
[0044] N,N,N',N'-tetra-2-naphthyl-4,4'-diaminobiphenyl
[0045] N-Phenylcarbazole
[0046] 4,4'-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl
[0047] 4,4'-Bis[N-(1-naphthyl)-N-(2-naphthyl)amino]biphenyl
[0048] 4,4"-Bis[N-(1-naphthyl)-N-phenylamino]p-terphenyl
[0049] 4,4'-Bis[N-(2-naphthyl)-N-phenylamino]biphenyl
[0050] 4,4'-Bis[N-(3-acenaphthenyl)-N-phenylamino]biphenyl
[0051] 1,5-Bis[N-(1-naphthyl)-N-phenylamino]naphthalene
[0052] 4,4'-Bis[N-(9-anthryl)-N-phenylamino]biphenyl
[0053] 4,4"-Bis[N-(1-anthryl)-N-phenylamino]-p-terphenyl
[0054] 4,4'-Bis[N-(2-phenanthryl)-N-phenylamino]biphenyl
[0055] 4,4'-Bis[N-(8-fluoranthenyl)-N-phenylamino]biphenyl
[0056] 4,4'-Bis[N-(2-pyrenyl)-N-phenylamino]biphenyl
[0057] 4,4'-Bis[N-(2-naphthacenyl)-N-phenylamino]biphenyl
[0058] 4,4'-Bis[N-(2-perylenyl)-N-phenylamino]biphenyl
[0059] 4,4'-Bis[N-(1-coronenyl)-N-phenylamino]biphenyl
[0060] 2,6-Bis(di-p-tolylamino)naphthalene
[0061] 2,6-Bis[di-(1-naphthyl)amino]naphthalene
[0062] 2,6-Bis[N-(1-naphthyl)-N-(2-naphthyl)amino]naphthalene
[0063] N,N,N',N'-Tetra(2-naphthyl)-4,4"-diamino-p-terphenyl
[0064]
4,4'-Bis{N-phenyl-N-[4-(1-naphthyl)-phenyl]amino}biphenyl
[0065] 4,4'-Bis[N-phenyl-N-(2-pyrenyl)amino]biphenyl
[0066] 2,6-Bis[N,N-di(2-naphthyl)amine]fluorene
[0067] 1,5-Bis[N-(1-naphthyl)-N-phenylamino]naphthalene
[0068] Another class of useful hole-transporting materials includes
polycyclic aromatic compounds as described in EP 1 009 041. In
addition, polymeric hole-transporting materials can be used such as
poly(N-vinylcarbazole) (PVK), polythiophenes, polypyrrole,
polyaniline, and copolymers such as
poly(3,4-ethylenedioxythiophene)/poly(4-styrenesul- fonate) also
called PEDOT/PSS.
[0069] Light-Emitting Layer (LEL)
[0070] As more fully described in U.S. Patent Nos.
commonly-assigned U.S. Pat. Nos. 4,769,292 and 5,935,721, the
light-emitting layer (LEL) 17 of the organic EL element includes a
luminescent or fluorescent material where electroluminescence is
produced as a result of electron-hole pair recombination in this
region. The light-emitting layer can be comprised of a single
material, but more commonly consists of a host material doped with
a guest compound or compounds where light emission comes primarily
from the dopant and can be of any color. The host materials in the
light-emitting layer can be an electron-transporting material, as
defined below, a hole-transporting material, as defined above, or
another material or combination of materials that support
hole-electron recombination. The dopant is usually chosen from
highly fluorescent dyes, but phosphorescent compounds, e.g.,
transition metal complexes as described in WO 98/55561, WO
00/18851, WO 00/57676, and WO 00/70655 are also useful. Dopants are
typically coated as 0.01 to 10% by weight into the host material.
Polymeric materials such as polyfluorenes and polyvinylarylenes
(e.g., poly(p-phenylenevinylene), PPV) can also be used as the host
material. In this case, small molecule dopants can be molecularly
dispersed into the polymeric host, or the dopant could be added by
copolymerizing a minor constituent into the host polymer.
[0071] An important relationship for choosing a dye as a dopant is
a comparison of the bandgap potential which is defined as the
energy difference between the highest occupied molecular orbital
and the lowest unoccupied molecular orbital of the molecule. For
efficient energy transfer from the host to the dopant molecule, a
necessary condition is that the band gap of the dopant is smaller
than that of the host material.
[0072] Host and emitting molecules known to be of use include, but
are not limited to, those disclosed in commonly-assigned U.S. Pat.
Nos. 4,768,292; 5,141,671; 5,150,006; 5,151,629; 5,405,709;
5,484,922; 5,593,788; 5,645,948; 5,683,823; 5,755,999; 5,928,802;
5,935,720; 5,935,721; and 6,020,078.
[0073] Metal complexes of 8-hydroxyquinoline (oxine) and similar
derivatives constitute one class of useful host compounds capable
of supporting electroluminescence. Illustrative of useful chelated
oxinoid compounds are the following:
[0074] CO-1: Aluminum trisoxine [alias,
tris(8-quinolinolato)aluminum(III)- ]
[0075] CO-2: Magnesium bisoxine [alias,
bis(8-quinolinolato)magnesium(II)]
[0076] CO-3: Bis[benzo{f}-8-quinolinolato]zinc (II)
[0077] CO-4:
Bis(2-methyl-8-quinolinolato)aluminum(III)-.mu.-oxo-bis(2-met-
hyl-8-quinolinolato) aluminum(III)
[0078] CO-5: Indium trisoxine [alias,
tris(8-quinolinolato)indium]
[0079] CO-6: Aluminum tris(5-methyloxine) [alias,
tris(5-methyl-8-quinolin- olato) aluminum(III)]
[0080] CO-7: Lithium oxine [alias, (8-quinolinolato)lithium(I)]
[0081] CO-8: Gallium oxine [alias,
tris(8-quinolinolato)gallium(III)]
[0082] CO-9: Zirconium oxine [alias,
tetra(8-quinolinolato)zirconium(IV)]
[0083] Other classes of useful host materials include, but are not
limited to: derivatives of anthracene, such as
9,10-di-(2-naphthyl)anthracene and derivatives thereof,
distyrylarylene derivatives as described in U.S. Pat. No.
5,121,029, and benzazole derivatives, for example,
2,2',2"-(1,3,5-phenylene)tris[1-phenyl-1H-benzimidazole].
[0084] Useful fluorescent dopants include, but are not limited to,
derivatives of anthracene, tetracene, xanthene, perylene, rubrene,
coumarin, rhodamine, quinacridone, dicyanomethylenepyran compounds,
thiopyran compounds, polymethine compounds, pyrilium and
thiapyrilium compounds, fluorene derivatives, periflanthene
derivatives and carbostyryl compounds.
[0085] Electron-Transporting Layer (ETL)
[0086] Preferred thin film-forming materials for use in forming the
electron-transporting layer 19 of the organic EL elements of this
invention are metal chelated oxinoid compounds, including chelates
of oxine itself (also commonly referred to as 8-quinolinol or
8-hydroxyquinoline). Such compounds help to inject and transport
electrons, exhibit high levels of performance, and are readily
fabricated in the form of thin films. Exemplary oxinoid compounds
were listed previously.
[0087] Other electron-transporting materials include various
butadiene derivatives as disclosed in commonly-assigned U.S. Pat.
No. 4,356,429 and various heterocyclic optical brighteners as
described in commonly-assigned U.S. Pat. No. 4,539,507. Benzazoles
and triazines are also useful electron-transporting materials.
[0088] In some instances, layers 17 and 19 can optionally be
collapsed into a single layer that serves the function of
supporting both light emission and electron transport. These layers
can be collapsed in both small molecule OLED systems and in
polymeric OLED systems. For example, in polymeric systems, it is
common to employ a hole-transporting layer such as PEDOT-PSS with a
polymeric light-emitting layer such as PPV. In this system, PPV
serves the function of supporting both light emission and electron
transport.
[0089] Cathode
[0090] When light emission is viewed solely through the anode, the
cathode 16 used in this invention can be comprised of nearly any
conductive material. Desirable materials have good film-forming
properties to ensure good contact with the underlying organic
layer, promote electron injection at low voltage, and have good
stability. Useful cathode materials often contain a low work
function metal (<4.0 eV) or metal alloy. One preferred cathode
material is comprised of a Mg:Ag alloy wherein the percentage of
silver is in the range of 1 to 20%, as described in
commonly-assigned U.S. Pat. No. 4,885,221. Another suitable class
of cathode materials includes bilayers including a thin
electron-injection layer (EIL) in contact with the organic layer
(e.g., ETL) which is capped with a thicker layer of a conductive
metal. Here, the EIL preferably includes a low work function metal
or metal salt, and if so, the thicker capping layer does not need
to have a low work function. One such cathode is comprised of a
thin layer of LiF followed by a thicker layer of Al as described in
commonly-assigned U.S. Pat. No. 5,677,572. Other useful cathode
material sets include, but are not limited to, those disclosed in
commonly-assigned U.S. Pat. Nos. 5,059,861; 5,059,862, and
6,140,763.
[0091] When light emission is viewed through the cathode, the
cathode must be transparent or nearly transparent. For such
applications, metals must be thin or one must use transparent
conductive oxides, or a combination of these materials. Optically
transparent cathodes have been described in more detail in U.S.
Pat. Nos. 4,885,211; 5,247,190, JP 3,234,963; 5,703,436; 5,608,287;
5,837,391; 5,677,572; 5,776,622; 5,776,623; 5,714,838; 5,969,474;
5,739,545; 5,981,306; 6,137,223; 6,140,763; 6,172,459, EP 1 076
368, and U.S. Pat. No. 6,278,236. Cathode materials are typically
deposited by evaporation, sputtering, or chemical vapor deposition.
When needed, patterning can be achieved through many well known
methods including, but not limited to, through-mask deposition,
integral shadow masking as described in commonly-assigned U.S. Pat.
No. 5,276,380 and EP 0 732 868, laser ablation, and selective
chemical vapor deposition.
[0092] Deposition of Organic Layers
[0093] The organic materials mentioned above are suitably deposited
through a vapor-phase method such as sublimation, but can be
deposited from a fluid, for example, from a solvent with an
optional binder to improve film formation. If the material is a
polymer, solvent deposition is useful but other methods can be
used, such as sputtering or thermal transfer from a donor sheet.
The material to be deposited by sublimation can be vaporized from a
sublimator "boat" often comprised of a tantalum material, e.g., as
described in commonly-assigned U.S. Pat. No. 6,237,529, or can be
first coated onto a donor sheet and then sublimed in closer
proximity to the substrate. Layers with a mixture of materials can
utilize separate sublimator boats or the materials can be pre-mixed
and coated from a single boat or donor sheet. Patterned deposition
can be achieved using shadow masks, integral shadow masks
(commonly-assigned U.S. Pat. No. 5,294,870), spatially-defined
thermal dye transfer from a donor sheet (commonly-assigned U.S.
Pat. Nos. 5,851,709 and 6,066,357) and inkjet method
(commonly-assigned U.S. Pat. No. 6,066,357).
[0094] Encapsulation
[0095] Most OLED apparatus are sensitive to moisture or oxygen, or
both, so they are commonly sealed in an inert atmosphere such as
nitrogen or argon, along with a desiccant such as alumina, bauxite,
calcium sulfate, clays, silica gel, zeolites, alkaline metal
oxides, alkaline earth metal oxides, sulfates, or metal halides and
perchlorates. Methods for encapsulation and desiccation include,
but are not limited to, those described in commonly-assigned U.S.
Pat. No. 6,226,890. In addition, barrier layers such as SiOx,
Teflon, and alternating inorganic/polymeric layers are known in the
art for encapsulation.
[0096] Optical Optimization
[0097] The OLED apparatus of, this invention employs a plurality of
OLED devices that use various well-known optical effects in order
to enhance its properties if desired. This includes optimizing
layer thickness to yield maximum light transmission, providing
dielectric mirror structures, replacing reflective electrodes with
light-absorbing electrodes, providing anti glare or anti-reflection
coatings over the display, providing a polarizing medium over the
display, or providing colored, neutral density, or color conversion
filters over the display. Filters, polarizers, and anti-glare or
anti-reflection coatings may be specifically provided over the
cover or as part of the cover.
[0098] FIG. 3 is a schematic representation of the cross-section of
an OLED apparatus 300 according to the present invention having a
plurality of OLED devices 32, 34, 36,and 38 connected in series.
For ease of illustration, only four OLED devices 32, 34, 36,and 38
are shown. It is understood that in most applications many more
OLED devices will be involved. On top of substrate 10 there is a
plurality of spaced apart bottom electrodes 22, 24, 26, and 28 one
for each OLED device. The spaced apart bottom electrodes 22, 24,
26, and 28 can be provided by vacuum deposition through masks or
printed into the desired pattern using ink containing the electrode
material. Alternatively, the spaced apart bottom electrodes 22, 24,
26, and 28 can be prepared in a continuous layer and divided into
the desired spaced apart pattern using photolithography, laser
scribing, or mechanical scribing. Over the spaced apart bottom
electrodes 22, 24, 26, and 28, there is disposed a plurality of
spaced apart organic EL elements, 42, 44, 46, and 48. Each one of
the spaced apart organic EL elements 42, 44, 46 and 48 has at least
one organic layer that extends over an edge of its corresponding
spaced apart bottom electrodes 22, 24, 26 and 28. In FIG. 3 each
spaced apart organic EL elements 42, 44, 46, and 48 covers the left
edge of its corresponding spaced apart bottom electrodes 22, 24, 26
and 28. The organic layers of each organic EL element 42, 44, 46
and 48 can end in the space between adjacent spaced apart bottom
electrodes 22, 24, 26, and 28 or it can extend beyond the space and
covers the right edge of the next spaced apart bottom electrode 22,
24, 26, and 28 to its left. Over the spaced apart organic EL
elements 42, 44, 46 and 48, there is disposed a plurality of spaced
apart top electrodes 62, 64, 66, and 68. Each spaced apart top
electrode 62, 64, 66, and 68 is disposed over a substantial portion
of its corresponding spaced apart organic EL element 42, 44, 46,
and 48. A set of corresponding spaced apart bottom electrode,
spaced apart organic EL element, and spaced apart top electrode
forms an OLED device that can emit light. Each spaced apart top
electrode extends beyond the space between its corresponding bottom
electrode and the next space apart bottom electrode and makes
electrical contact with the latter. Thus the spaced apart top
electrode of OLED device 38 contacts the spaced apart bottom
electrode of OLED device 36; the spaced apart top electrode of OLED
device 36 contacts the spaced apart bottom electrode of OLED device
34; and so on. In operation a voltage is applied between the top
electrode 62 of device 32 and the bottom electrode 28 of device 38
and the operating current flows from one device into the next
causing all device to emit simultaneously. The drive voltage is the
sum of that of the four OLED devices 32, 34, 36 and 38, but the
drive current is that of a single OLED device which is only one
quarter of that of a single OLED device of equivalent total area as
the OLED apparatus 300. Since the power loss due to series
resistance equals the square of the operating current times the
series resistance, it is drastically reduced when compared with an
OLED including a single OLED device instead of four OLED devices.
The spaced apart organic EL elements and the spaced apart top
electrodes can be prepared by conventional masking, printing, or
scribing methods similar to those used for making spaced apart
bottom electrodes and selected based on the organic materials and
top electrode materials used.
[0099] OLED devices 32, 34, 36, and 38 can also be stacked OLED
devices. In this case each OLED device 32, 34, 36, and 38 includes
a spaced apart top electrode, a spaced apart bottom electrode, and
a plurality of individual light emitting devices stacked between
the two electrodes. There can be inter-device electrodes between
the neighboring individual light emitting devices, as taught in
U.S. Pat. No. 6,337,492. Alternatively, as taught by commonly
assigned U.S. patent application Ser. No. 10/077,720 by Liao et al,
a doped organic connector can be used between the individual light
emitting devices. FIG. 4 is a schematic representation of the cross
section of an OLED apparatus 400 including a plurality of stacked
OLED devices having inter-device electrodes. For ease of
illustration, each OLD devices 32, 34, 36, and 38 includes three
individual light emitting devices. OLED device 32, for example,
includes three individual light emitting devices 32a, 32b, 32c. The
top individual light emitting device 32a includes a spaced apart
top electrode 62a, a spaced apart light emitting element 42a, and a
spaced apart inter-device electrode 22a; the middle individual
emitting device 32b includes a spaced apart inter-device electrode
62b, a spaced apart light emitting element 42b, and a spaced apart
inter-device electrode 22b; the bottom individual emitting device
32c includes a spaced apart inter-device electrode 62c, a spaced
apart light emitting element 42c, and a spaced apart bottom
electrode 22c. The spaced apart top electrode 64a of the top
individual light emitting device 34a of OLED device 34 is made to
be in contact with the spaced apart bottom electrode 22c of the
bottom individual light emitting device 32c of OLED device 32. The
spaced apart top electrode 66a of the top individual light emitting
device 36a of OLED device 36 is made to be in contact with the
spaced apart bottom electrode 24c of the bottom individual light
emitting device 34c of OLED device 34; the spaced apart top
electrode 68a of the top individual light emitting device 38a of
OLED device 38 is made to be in contact with the spaced apart
bottom electrode 26c of the bottom individual light emitting device
36c of OLED device 36. OLED devices 32, 34, 36, and 38 are thus
connected in series. To operate the apparatus, an electric current
is applied between spaced apart top electrode 62a of the top
individual light emitting device 32a of OLED device 32 and the
spaced apart bottom electrode 28c of the bottom individual light
emitting device 38c of OLED device 38. This current will flow
through all the individual light emitting devices of all OLED
devices 32, 34, 36, and 38 and cause light to emit in all the
individual light emitting devices. Comparing with a conventional
OLED device having the same device area and operating at the same
brightness level, apparatus 400 according to the current invention
will operate at twelve times the voltage but only one twelfth of
the current. The loss due to series resistance is thus drastically
reduced.
[0100] Staying with FIG. 4 and use individual light emitting device
32b as an example, it can be seen that the inter-device spaced
apart top electrode 62b and the spaced apart bottom electrode 22b
do not need to have high lateral electrical conductance. The
function of these electrodes is to supply positive and negative
charges into the individual organic EL element 42b, and to have
enough electrical conductivity to allow current to flow through the
thickness of these layers. Material with electrical resistivity as
high as 10.sup.8 ohm-cm can be used for these inter-device
electrodes if the thickness of these electrodes is small. On the
other hand, the spaced apart top electrodes 62a, 64a, 66a, 68a of
the uppermost individual light emitting devices 32a, 34a, 36a, 38a;
and the spaced apart bottom electrodes 22c, 24c, 26c, 28c of the
lowermost individual light emitting devices 32a, 34c, 36c, 38c need
to have high lateral electrical conductance to reduce loss of
energy due to series resistance. For these layers, the electrical
resistivity needs to be 10.sup.-3 ohm-cm or lower. For fabricating
OLED apparatus according to the present invention using stacked
OLED devices it is in fact preferable to use materials of high
electrical resistivity for the inter-device electrodes. Focusing on
OLED device 38 in FIG. 4, the spaced apart top electrode 68a
extends to the left beyond the end edges of all the other layers
48a, 28a, 68b, 48b, 28b, 68c, 48c, 28c so that it is be made to
contact the spaced apart bottom electrode 26c of the next OLED
device 36. Using a high resistivity material for the inter-device
electrode layers 28a, 68b, 28b, 68c helps preventing the individual
light emitting devices from being shorted if there happen to be
accidental contacts between spaced apart electrode 68a and the
other inter-device electrode layers 28a, 68b, 28b, 68c.
[0101] Alternatively stacked OLED devices as taught by the
above-cited commonly-assigned U.S. patent application Ser. No.
10/077,720 by Liao et al. can be used. Instead of inter-device
electrodes, doped organic connectors are used in between the
stacked individual light emitting devices. FIG. 4a shows an OLED
apparatus 410 according to the present invention including serially
connected stacked OLED devices based on doped organic connectors.
On a common substrate 10 there are four OLED devices 32, 34, 36, 38
each including a stack of three individual light emitting devices.
Correspondingly there are four spaced apart top electrodes 62a,
64a, 66a, 68a; four spaced apart bottom electrodes 22c, 24c, 26c,
and 28c. Between each pair of spaced apart top electrodes and
spaced apart bottom electrodes, 62a and 22c; 64a and 24c; 66a and
26c; 68a and 28c, there are three individual light emitting devices
connected by doped organic connectors. For example, doped organic
connectors 23a and 23b are used to connect the three stacked
individual devices in OLED device 32, doped organic connectors 83a
and 83b are used to connect the three stacked individual devices in
OLED device 38, etc. The spaced apart top electrode of OLED device
34 is made to be in contact with the spaced bottom electrode 22c
OLED device 32. The spaced apart top electrode 66a of OLED device
36 is made to be in contact with the spaced apart bottom electrode
24c of OLED device 34; the spaced apart top electrode 68a OLED
device 38 is made to be in contact with the spaced bottom electrode
26c of OLED device 36. OLED devices 32, 34, 36, and 38 are thus
connected in series. To operate the apparatus, an electric current
is applied between spaced apart top electrode 62a of OLED device 32
and the spaced apart bottom electrode 28c of OLED device 38. This
current will flow through all the individual light emitting devices
of all OLED devices 32, 34, 36, and 38 and cause light to emit in
all the individual light emitting devices. Comparing with a
convention OLED device having the same device area and operating at
the same brightness level, apparatus 400 according to the current
invention will operate at twelve times the voltage but only one
twelfth of the current. The loss due to series resistance is thus
drastically reduced.
[0102] FIG. 5 is a schematic representation of the top view of OLED
apparatus 300 showing OLED devices 32, 34, 36, 38; their
corresponding spaced apart top-electrodes: 62, 64, 66, and 68; and
one spaced apart bottom electrode, 28.
[0103] In addition to reducing power loss due to series resistance,
another advantage of the present invention is that, when an OLED
apparatus is divided into OLED devices connected in series, a
shorting defect can only render the OLED device it resides in
non-operative. The remaining OLED devices in the series can
continue to emit light. The output of the OLED device as a whole is
reduced, but this situation is much better than having the entire
device totally non-operative due to a single shorting defect.
[0104] FIG. 6 depicts another embodiment of the present invention
showing an array 500 having five OLED apparatus 101, 102, 103, 104,
and 105, on a common substrate 10. Each of the five OLED apparatus
101, 102, 103, 104, and 105 includes four OLED devices connected in
series according to the present invention. For example, OLED
apparatus 101 includes OLED devices 132, 134, 136, and 138
connected in series. OLED apparatus 101, 102, 103, 104, and 105 are
electrically isolated from each other except at the ends where they
can be connected so that the five apparatus can operate in
parallel. This embodiment is used to divide a large area OLED
device into many small devices that are connected in series and
then in parallel. This embodiment not only reduces power loss due
to series resistance it further reduces damaging effect due to
shorting defects. If there is a shorting defect, only the OLED
device it resides in is affected. For example, if there is a
shorting defect in OLED device 236 of OLED apparatus 103, only OLED
device 236 is affected and the total output of array 500 is only
reduced by {fraction (1/20)}. Thus the impact of shorting defects
is greatly reduced.
[0105] In another embodiment of the present invention, OLED
apparatus 101, 102, 103, 104, and 105 can contain different organic
EL elements to emit light of different colors. Some of the OLED
apparatus can be made to emit blue lights, some red lights, and
some green lights. Each OLED apparatus can emit a single colored
light so as to form a repeating pattern of different colored light.
A conventional electrical structure can be used to connect the
bottom electrodes of the first OLED devices of all OLED apparatus
that produce the same colored light. Similarly, the top electrodes
of the last OLED devices of all OLED apparatus that produce the
same colored light can be connected. OLED apparatus 101, 102, 103,
104, and 105 can also be driven independently to achieve different
intensity levels. Alternatively, if OLED apparatus 101, 102, 103,
104, and 105 are not equally efficient, they can be driven to
different levels to achieve uniform intensity levels.
[0106] Alternatively the top electrode of the first OLED device in
each OLED apparatus of the array can be electrically connected and
the bottom electrode of the last OLED device of each OLED apparatus
of the array can be electrically connected. All the OLED apparatus
are thus connected in parallel and can be driven off a common power
supply.
[0107] FIG. 7 depicts another embodiment of the current invention
wherein pillar structures are used as built-in shadow masks for
fabricating the spaced apart organic EL elements 42, 44, 46 and 48
and the spaced apart top electrodes 62, 64, 66, and 68. In this
structure, a plurality of spaced apart bottom electrodes 22, 24,
26, and 28 are provided over substrate 10. A plurality of spaced
apart pillar structures 72 and 74 are then fabricated by
photolithography over the spaced apart bottom electrodes 22, 24, 26
and 28. A vacuum deposition process is then used to prepare the
spaced apart organic EL element 42, 44, 46 and 48 and the spaced
apart top electrode 62, 64, 66 and 68 using pillars 72 and 74 as
built-in shadow masks. The coating of organic element materials 43,
45, 47 on top of pillars 72, and 74 and the coating of top
electrode materials 63, 65, 67 on top of pillars 72 and 74 allows
the spaced apart organic EL element 42, 44, 46 and 48 and the
spaced apart top electrodes 62, 64, 66 and 68 to be spaced apart
from each other. The position of spaced apart pillars 72 and 74 are
such that each spaced apart top electrode is in contact with its
next adjacent spaced apart bottom electrode to form the series
connection.
[0108] The invention has been described in detail with particular
reference to certain preferred embodiments thereof, but it will be
understood that variations and modifications can be effected within
the spirit and scope of the invention.
[0109] Parts List
[0110] 10 substrate
[0111] 14 organic EL element
[0112] 15 hole transport layer
[0113] 19 electron transport layer
[0114] 12 anode layer
[0115] 13 hole injecting layer
[0116] 16 cathode layer
[0117] 17 light-emitting layer
[0118] 22 spaced apart bottom electrode
[0119] 22c apart bottom electrode
[0120] 22a inter-device electrode
[0121] 22b inter-device electrode
[0122] 23a doped organic connectors
[0123] 23b doped organic connectors
[0124] 24 spaced apart bottom electrode
[0125] 24c spaced apart bottom electrode
[0126] 26 spaced apart bottom electrode
[0127] 26c spaced apart bottom electrode
[0128] 28 spaced apart bottom electrode
[0129] 28c spaced apart bottom electrode
[0130] 28a inter-device electrode
[0131] 28b inter-device electrode
[0132] 32 OLED device
[0133] 32a individual light emitting device
[0134] 32b individual light emitting device
[0135] 32c individual light emitting device
[0136] 34 OLED device
[0137] 34a individual light emitting device
[0138] 34c individual light emitting device
[0139] Parts List Cont'd
[0140] 36 OLED device
[0141] 36a individual light emitting device
[0142] 36c individual light emitting device
[0143] 38 OLED device
[0144] 38a individual light emitting device
[0145] 38b individual light emitting device
[0146] 38c individual light emitting device
[0147] 42 spaced apart organic EL element
[0148] 42a spaced apart organic EL element
[0149] 42b spaced apart organic EL element
[0150] 42c spaced apart organic EL element
[0151] 43 organic EL element materials coated on top of pillars
[0152] 44 spaced apart organic EL element
[0153] 45 organic EL element materials coated on top of pillars
[0154] 46 spaced apart organic EL element
[0155] 47 organic EL element materials coated on top of pillars
[0156] 48 spaced apart organic EL element
[0157] 48a spaced apart organic EL element
[0158] 48b spaced apart organic EL element
[0159] 48c spaced apart organic EL element
[0160] 62b inter-device electrode
[0161] 62c inter-device electrode
[0162] 62 spaced apart top electrode
[0163] 62a spaced apart top electrode
[0164] 63 top electrode materials coated on top of pillars
[0165] 64 spaced apart top electrode
[0166] 64a spaced apart top electrode
[0167] 65 top electrode materials coated on top of pillars
[0168] Parts List Con'td
[0169] 66 spaced apart top electrode
[0170] 66a spaced apart top electrode
[0171] 67 top electrode materials coated on top of pillars
[0172] 68 spaced apart top electrode
[0173] 68a spaced apart top electrode
[0174] 68b inter-device electrode
[0175] 68c inter-device electrode
[0176] 72 pillar
[0177] 74 pillar
[0178] 83a doped organic connectors
[0179] 83b doped organic connectors
[0180] 100 conventional OLED device
[0181] 101 OLED apparatus
[0182] 102 OLED apparatus
[0183] 103 OLED apparatus
[0184] 104 OLED apparatus
[0185] 105 OLED apparatus
[0186] 132 OLED device
[0187] 134 OLED device
[0188] 136 OLED device
[0189] 138 OLED device
[0190] 200 conventional OLED device
[0191] 236 OLED device
[0192] 300 OLED apparatus
[0193] 400 OLED apparatus
[0194] 410 OLED apparatus
[0195] 500 array
* * * * *