Organic light-emitting device with meandering electrode surface, and method for manufacturing same
View Patent ↗An organic electroluminescent element has a substrate, a first electrode formed above the substrate, an emissive layer, and a second electrode formed above the emissive layer. In the first electrode, at least a surface opposite to the other surface facing the substrate has a multidimensionally meandering surface shape. The emissive layer includes an organic electroluminescent material and is formed along the multidimensionally-meandering-shaped surface of the first electrode. In the emissive layer, a surface facing the first electrode and the other surface opposite to the first-electrode-facing surface each have a multidimensionally meandering surface shape. The organic electroluminescent element of the present invention is used in an electroluminescent (EL) type display device as a pixel that is controlled individually for light emission. Also, the organic electroluminescent element of the present invention is used as a light source of an electroluminescent (EL) type lighting system. As a result, an organic electroluminescent element with high luminance and an organic electroluminescent element with a long lifetime are provided, and an EL display device and an EL lighting system using such elements are provided.
1. An organic electroluminescent element comprising:
a substrate having a first surface;
a first electrode located above the first surface of the substrate, the first electrode having a first surface adjacent to the substrate and second surface opposite the first surface;
an emissive layer including an organic electroluminescent material, the emissive layer located on the second surface of the first electrode and having a first surface adjacent to the first electrode and a second surface opposite the first surface; and
a second electrode located on the second surface of the emissive layer;
wherein the organic electroluminescent element is viewed as intersected by an imaginary first plane perpendicular to the first surface of the substrate and a plurality of imaginary second planes parallel to the first plane, such that every one of such plurality of imaginary second planes is spaced from such first plane, and such first plane and second planes define a first cross-section, corresponding to the first imaginary plane, and a plurality of second cross-sections, corresponding to the plurality of imaginary second planes, of the organic electroluminescent element, the second surface of the first electrode having a multidimensionally meandering surface shape such that:
such a first cross-section of the second surface of the first electrode meanders,
every second cross-section of the second surface of the first electrode meanders in a way that differs from the meandering shape of the first cross-section, and
the first and second cross-sections meander in directions other than perpendicular to the substrate; and
wherein the first and second surfaces of the emissive layer have a multidimensionally meandering surface shape such that:
such a first cross-section of the emissive layer meanders,
every second cross-section of the emissive layer meanders in a way that differs from the meandering shape of the first cross-section, and
the first and second cross-sections of the emissive layer meander in directions other than perpendicular to the substrate.
2. The organic electroluminescent element according to claim 1 , wherein a thickness of the emissive layer is uniform.
3. The organic electroluminescent element according to claim 2 , wherein:
in each of six pairs of cross-sections of the organic electroluminescent element resulting from three ways of cutting thereof, an actual length of a meandering-shaped line of the emissive layer and a projected length of the meandering-shaped line meet the following Inequality 1 , the three ways of cutting being perpendicular to the substrate and crossing each other at an angle of 60 degrees and at an arbitrary intersection point on the substrate, the projected length of the meandering-shaped line being a length of the meandering-shaped line projected onto a plane parallel to the substrate and projected from a direction perpendicular to the substrate:
∑
n
=
1
6
(
actual
length
of
meandering
shaped
line
of
nth
cut
section
)
(
its
projected
length
)
6
≥
2.
(
1
)
4. The organic electroluminescent element according to claim 1 , wherein a first surface of the second electrode faces the emissive layer and has a multidimensionally meandering surface shape such that:
such a first cross-section of the first surface of the second electrode meanders,
every second cross-section of the first surface of the second electrode meanders in a way that differs from the meandering shape of the first cross-section, and
the first and second cross-sections meander in directions other than perpendicular to the substrate.
5. A method of fabricating an organic electroluminescent element comprising:
preparing a substrate having a first surface;
forming a first electrode above the substrate, the first electrode having a first surface adjacent to the first surface of the substrate and a second surface opposite the first surface of the first electrode;
forming an emissive layer above the second surface of the first electrode; and
forming a second electrode above the emissive layer;
wherein the first electrode is formed by any of the following methods (A) to (D):
(A) dissolving and solidifying metal in an inert gas;
(B) removing a removable fiber from a lump of metal in which the removable fiber is mixed;
(C) etching the surface of a lump of metal; or
(D) pressure forming finely powdered metal;
wherein the organic electroluminescent element is viewed as intersected by an imaginary first plane perpendicular to the first surface of the substrate and a plurality of imaginary second planes parallel to the first plane, such that every one of such plurality of imaginary second planes is spaced from such first plane, and such first plane and second planes define a first cross- section, corresponding to the first imaginary plane, and a plurality of second cross-sections, corresponding to the plurality of imaginary second planes, of the organic electroluminescent element,
and wherein the second surface of the first electrode has a multidimensionally meandering surface shape such that:
such a first cross-section of the second surface of the first electrode meanders,
every second cross-section of the second surface of the first electrode meanders in a way that differs from the meandering shape of the first cross-section, and
the first and second cross-sections meander in directions other than perpendicular to the substrate; and
wherein the emissive layer has a multidimensionally meandering surface shape such that:
such a first cross-section of the emissive layer meanders,
every second cross-section of the emissive layer meanders in a way that differs from the meandering shape of the first cross-section, and
the first and second cross-sections of the emissive layer meander in directions other than perpendicular to the substrate.
6. The method of fabricating an organic electroluminescent element according to claim 5 , wherein the organic electroluminescent material is deposited uniformly along the multidimensionally meandering surface of the first electrode by means of electrolytic deposition.
7. A display device comprising:
a substrate;
an electronic circuit formed on the substrate; and
at least one organic electroluminescent element, light emission thereof being controlled via the electronic circuit, the organic electroluminescent element comprising:
a substrate having a first surface;
a first electrode located above the substrate and having a first surface adjacent to the first surface of the substrate and a second surface opposite the first surface of the first electrode;
an emissive layer including an organic electroluminescent material, the emissive layer formed along the second surface of the first electrode; and
a second electrode located above the emissive layer;
wherein the organic electroluminescent element is viewed as intersected by an imaginary first plane perpendicular to the first surface of the substrate and a plurality of imaginary second planes parallel to the first plane, such that every one of such plurality of imaginary second planes is spaced from such first plane, and such first plane and second planes define a first cross-section, corresponding to the first imaginary plane, and a plurality of second cross-sections, corresponding to the plurality of imaginary second planes, of the organic electroluminescent element,
the second surface of the first electrode has a multidimensionally meandering surface shape such that:
such a first cross-section of the second surface of the first electrode meanders,
every second cross-section of the second surface of the first electrode meanders in a way that differs from the meandering shape of the first cross-section, and
the first and second cross-sections meander in directions other than perpendicular to the substrate; and
wherein the emissive layer has a multidimensionally meandering surface shape such that:
such a first cross-section of the emissive layer meanders,
every second cross-section of the emissive layer meanders in a way that differs from the meandering shape of the first cross-section, and
the first and second cross-sections of the emissive layer meander in directions other than perpendicular to the substrate.
8. A lighting system comprising a substrate, a voltage application wire located on the substrate, and at least one organic electroluminescent element electrically connected with the voltage application wire, the organic electroluminescent element comprising:
a substrate having a first surface;
a first electrode located above the substrate, the first electrode having a first surface adjacent to the first surface of the substrate and a second surface opposite the first surface of the first electrode;
an emissive layer including an organic electroluminescent material, the emissive layer formed along the second surface of the first electrode; and
a second electrode located above the emissive layer;
wherein the organic electroluminescent element is viewed as intersected by an imaginary first plane perpendicular to the first surface of the substrate and a plurality of imaginary second planes parallel to the first plane, such that every one of such plurality of imaginary second planes is spaced from such first plane, and such first plane and second planes define a first cross-section, corresponding to the first imaginary plane, and a plurality of second cross-sections, corresponding to the plurality of imaginary second planes, of the organic electroluminescent element,
the second surface of the first electrode has a multidimensionally meandering surface shape such that:
such a first cross-section of the second surface of the first electrode meanders, the cross-section being perpendicular to the first surface of the substrate,
every second cross-section of the second surface of the first electrode meanders in a way that differs from the meandering shape of the first cross-section, and
the first and second cross-sections meander in directions other than perpendicular to the substrate; and
wherein the emissive layer has a multidimensionally meandering surface shape such that:
such a first cross-section of the emissive layer meanders,
every second cross-section of the emissive layer meanders in a way that differs from the meandering shape of the first cross-section, and
the first and second cross-sections of the emissive layer meander in directions other than perpendicular to the substrate.