U.S. patent application number 16/381334 was filed with the patent office on 2019-08-01 for display apparatus with bending area capable of minimizing manufacturing defects.
The applicant listed for this patent is SAMSUNG DISPLAY CO., LTD.. Invention is credited to DEUKJONG KIM, KEONWOO KIM, YONGJIN KIM, DONGHYUN LEE.
Application Number | 20190237516 16/381334 |
Document ID | / |
Family ID | 57396311 |
Filed Date | 2019-08-01 |
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United States Patent
Application |
20190237516 |
Kind Code |
A1 |
KIM; KEONWOO ; et
al. |
August 1, 2019 |
DISPLAY APPARATUS WITH BENDING AREA CAPABLE OF MINIMIZING
MANUFACTURING DEFECTS
Abstract
A display apparatus includes a substrate, an inorganic
insulating layer, a first conductive layer, and an organic material
layer. The substrate includes a first area, a second area, and a
bending area located between the first area and the second area the
bending area configured to be bent about a first bending axis
extending in a first direction. The inorganic insulating layer is
arranged over the substrate. The first conductive layer extends
from the first area to the second area passing over the bending
area, and is arranged over the inorganic insulating layer. The
organic material layer is arranged between the inorganic insulating
layer and the first conductive layer and includes a central portion
overlapping the bending area and a peripheral portion extending
from the central portion. An average thickness of the central
portion is greater than an average thickness of the peripheral
portion.
Inventors: |
KIM; KEONWOO; (YONGIN-SI,
KR) ; KIM; DEUKJONG; (YONGIN-SI, KR) ; KIM;
YONGJIN; (YONGIN-SI, KR) ; LEE; DONGHYUN;
(YONGIN-SI, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG DISPLAY CO., LTD. |
YONGIN-SI |
|
KR |
|
|
Family ID: |
57396311 |
Appl. No.: |
16/381334 |
Filed: |
April 11, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15332415 |
Oct 24, 2016 |
10283574 |
|
|
16381334 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 27/323 20130101;
G06F 3/0416 20130101; H01L 2251/5338 20130101; Y02E 10/549
20130101; G06F 3/0412 20130101; H01L 51/0097 20130101; H01L 51/5253
20130101; Y02P 70/521 20151101; H01L 27/3276 20130101; H01L 27/3258
20130101; H01L 27/3246 20130101; Y02P 70/50 20151101 |
International
Class: |
H01L 27/32 20060101
H01L027/32; G06F 3/041 20060101 G06F003/041; H01L 51/52 20060101
H01L051/52; H01L 51/00 20060101 H01L051/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 25, 2016 |
KR |
10-2016-0036132 |
Jun 21, 2016 |
KR |
10-2016-0077554 |
Claims
1. A display apparatus comprising: a substrate comprising a first
area, a second area, and a bending area located between the first
area and the second area, the bending area configured to be bent
about a first bending axis extending in a first direction; an
inorganic insulating layer arranged over the substrate; a first
conductive layer extending from the first area to the second area
passing over the bending area, and arranged over the inorganic
insulating layer; and an organic material layer arranged between
the inorganic insulating layer and the first conductive layer, and
comprising a central portion and a peripheral portion, wherein the
central portion overlaps with the bending area, the peripheral
portion extends from the central portion, and an average thickness
of the central portion is greater than an average thickness of the
peripheral portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/332,415 filed Oct. 24, 2016, which claims
the benefit of Korean Patent Application No. 10-2016-0036132, filed
on Mar. 25, 2016 in the Korean Intellectual Property Office, and
Korean Patent Application No. 10-2016-0077554, filed on Jun. 21,
2016 in the Korean Intellectual Property Office, the disclosures of
which are incorporated by reference herein in their entirety.
TECHNICAL FIELD
[0002] Exemplary embodiments of the inventive concept relate to a
display apparatus, and more particularly, to a display apparatus
capable of minimizing the occurrence of defects, such as
disconnections, that may occur during manufacturing processes,
while ensuring a longer lifespan of the display apparatus.
DISCUSSION OF RELATED ART
[0003] A display apparatus, which visually displays data, includes
a substrate divided into a display area and a non-display area. In
the display area, gate lines and data lines are insulated from each
other and a plurality of pixel areas are defined by crossing the
gate lines and the data lines. Also, in the display area, thin film
transistors (TFTs) and pixel electrodes electrically connected to
the TFTs are provided to the pixel areas. In the non-display area,
various conductive layers, such as wirings transmitting electrical
signals to the display area, are provided.
[0004] At least a portion of the display apparatus may be bent to
enhance visibility at various angles or decrease the size of the
non-display area. Various techniques are being developed for
reducing defects and reducing costs during the manufacturing of
these bent display apparatuses.
SUMMARY
[0005] According to an exemplary embodiment of the inventive
concept, a display apparatus includes: a substrate including a
first area, a second area, and a bending area located between the
first area and the second area, the bending area configured to be
bent about a first bending axis extending in a first direction; an
inorganic insulating layer arranged over the substrate; a first
conductive layer extending from the first area to the second area
passing over the bending area, and arranged over the inorganic
insulating layer; and an organic material layer arranged between
the inorganic insulating layer and the first conductive layer, and
including a central portion and a peripheral portion. The central
portion overlaps with the bending area. The peripheral portion
extends from the central portion. An average thickness of the
central portion is greater than an average thickness of the
peripheral portion.
[0006] According to an exemplary embodiment of the inventive
concept, the inorganic insulating layer may have a flat upper
surface at an area overlapping with the organic material layer.
[0007] According to an exemplary embodiment of the inventive
concept, the central portion may have a substantially uniform
thickness.
[0008] According to an exemplary embodiment of the inventive
concept, the peripheral portion may include an area having a
substantially uniform thickness, and a thickness of the peripheral
portion may decrease in a direction away from the central
portion.
[0009] According to an exemplary embodiment of the inventive
concept, a thickness of the peripheral portion may gradually
decrease in a direction away from the central portion.
[0010] According to an exemplary embodiment of the inventive
concept, the organic material layer may include a first organic
material layer, and a second organic material layer arranged on the
first organic material layer. The first organic material has a
first width. The second organic material layer has a second width
smaller than the first width. The second width may be greater than
a width of the bending area.
[0011] According to an exemplary embodiment of the inventive
concept, the organic material layer may have an uneven surface at
least partially in an upper surface of the organic material
layer.
[0012] According to an exemplary embodiment of the inventive
concept, the organic material layer may have the uneven surface in
the central portion.
[0013] According to an exemplary embodiment of the inventive
concept, an upper surface of the first conductive layer over the
organic material layer may have a shape corresponding to a shape of
the upper surface of the organic material layer.
[0014] According to an exemplary embodiment of the inventive
concept, the inorganic insulating layer may have a groove in an
area overlapping with the organic material layer.
[0015] According to an exemplary embodiment of the inventive
concept, an area of the groove may be larger than an area of the
bending area.
[0016] According to an exemplary embodiment of the inventive
concept, the organic material layer may cover an inner surface of
the groove.
[0017] According to an exemplary embodiment of the inventive
concept, a height of the organic material layer from an upper
surface of the substrate may be greater than a height of the
inorganic insulating layer from the upper surface of the
substrate.
[0018] According to an exemplary embodiment of the inventive
concept, a height of the peripheral portion from an upper surface
of the substrate may gradually decrease in a direction away from
the central portion.
[0019] According to an exemplary embodiment of the inventive
concept, a height of the organic material layer from an upper
surface of the substrate may be less than a height of the inorganic
insulating layer from the upper surface of the substrate.
[0020] According to an exemplary embodiment of the inventive
concept, an area of the uneven surface may be larger than an area
of the central portion.
[0021] According to an exemplary embodiment of the inventive
concept, the display apparatus may further include a protective
film disposed on a lower surface of the substrate. The lower
surface may be opposite a surface of the substrate nearest to the
inorganic insulating layer. The protective film includes an opening
corresponding to the bending area.
[0022] According to an exemplary embodiment of the inventive
concept, an area of the opening may be larger than an area of the
bending area.
[0023] According to an exemplary embodiment of the inventive
concept, the display apparatus may further include: an
encapsulation layer covering a display device over the first area;
and a touch electrode configured to provide a touchscreen and
located over the encapsulation layer. The first conductive layer
may include substantially the same material as that of the touch
electrode.
[0024] According to an exemplary embodiment of the inventive
concept, the display apparatus may further include a touch
protective layer covering the touch electrode and the first
conductive layer.
[0025] According to an exemplary embodiment of the inventive
concept, the display apparatus may further include: a thin film
transistor (TFT) arranged over the first area or the second area
and including a source electrode, a drain electrode, and a gate
electrode; and a planarization layer covering the TFT and including
an organic material. The organic material layer may include
substantially the same material as that of the planarization
layer.
[0026] According to an exemplary embodiment of the inventive
concept, the display apparatus may further include: an organic
light-emitting device arranged over the first area and including a
pixel electrode, an opposite electrode facing the pixel electrode,
and an intermediate layer including an organic emission layer and
arranged between the pixel electrode and the opposite electrode;
and a pixel defining layer arranged over the first area, the pixel
defining layer having an opening that exposes a center portion of
the pixel electrode and defines a pixel area. The organic material
layer may include substantially the same material as that of the
pixel defining layer.
[0027] According to an exemplary embodiment of the inventive
concept, the display apparatus may further include an encapsulation
layer including a first inorganic encapsulation layer, a second
inorganic encapsulation layer, and an organic encapsulation layer
between the first inorganic encapsulation layer and the second
inorganic encapsulation layer and covering a display device over
the first area. The organic material layer may include
substantially the same material as that of the organic
encapsulation layer.
[0028] According to an exemplary embodiment of the inventive
concept, the display apparatus may further include a second
conductive layer arranged over the first area or the second area.
The second conductive layer is located on a layer different from a
layer on which the first conductive layer is located. The second
conductive layer is electrically connected to the first conductive
layer.
[0029] According to an exemplary embodiment of the inventive
concept, an elongation rate of the first conductive layer may be
greater than that of the second conductive layer.
[0030] According to an exemplary embodiment of the inventive
concept, the display apparatus may further include a TFT arranged
over the first area or the second area and including a source
electrode, a drain electrode, and a gate electrode. The first
conductive layer may be on a same layer as the source electrode and
the drain electrode. The second conductive layer may be on a same
layer as the gate electrode.
[0031] According to an exemplary embodiment of the inventive
concept, the display apparatus may further include a stress
neutralization layer arranged over an upper portion of the first
conductive layer.
[0032] According to an exemplary embodiment of the inventive
concept, a display apparatus includes a substrate, an inorganic
insulating layer, a first conductive layer, and an organic material
layer. The substrate is divided into a first area, a second area,
and a bending area located between the first area and the second
area. The bending area is configured to be bent about a first
bending axis extending in a first direction. The inorganic
insulating layer is arranged over the substrate. The first
conductive layer extends from the first area to the second area
passing over the bending area, and is arranged over the inorganic
insulating layer. The organic material layer is arranged between
the inorganic insulating layer and the first conductive layer, and
includes a central portion and a peripheral portion. The central
portion overlaps with the bending area. The peripheral portion
extends from the central portion. An average thickness of the
central portion is greater than an average thickness of the
peripheral portion. The substrate has a multi-layer structure
extending through the first area, the second area, and the bending
area. The substrate includes a first resin layer, a barrier layer,
an intermediate layer, and a second resin layer. The first resin
layer includes a polymer resin. The barrier layer includes an
inorganic material and is disposed over the first resin layer. The
intermediate layer includes an amorphous material and is disposed
over the barrier layer. The second resin layer includes a polymer
resin and is disposed over the intermediate layer.
[0033] According to an exemplary embodiment of the inventive
concept, the first conductive layer may extend from the first area
to the second area in a second direction perpendicular to the first
direction, and the first conductive layer may form a wavy pattern
while extending in the second direction.
[0034] According to an exemplary embodiment of the inventive
concept, the display apparatus further includes a protective film
disposed on a lower surface of the substrate. The lower surface is
opposite a surface of the substrate nearest to the inorganic
insulating layer. The protective film includes an opening
corresponding to the bending area. An area of the opening is larger
than an area of the bending area and smaller than an area of the
organic material layer.
[0035] According to an exemplary embodiment of the inventive
concept, the organic material layer has an uneven surface at least
partially in an upper surface of the organic material layer, and an
upper surface of the first conductive layer over the organic
material layer has an uneven surface with a shape that is
independent of a shape of the uneven surface of the organic
material layer.
[0036] According to an exemplary embodiment of the inventive
concept, an upper surface of the inorganic insulating layer and an
upper surface of the peripheral portion of the organic material
layer contact, forming an angle that is less than or equal to 45
degrees.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The above and other features of the inventive concept will
become apparent and more clearly understood by describing in detail
exemplary embodiments thereof with reference to the accompanying
drawings.
[0038] FIG. 1 is a schematic perspective view partially showing a
display apparatus according to an exemplary embodiment of the
inventive concept.
[0039] FIG. 2 is a schematic cross-sectional view partially showing
the display apparatus of FIG. 1 according to an exemplary
embodiment of the inventive concept.
[0040] FIG. 3A is a schematic cross-sectional view partially
showing a display apparatus according to an exemplary embodiment of
the inventive concept.
[0041] FIG. 3B is a schematic cross-sectional view partially
showing a display apparatus according to an exemplary embodiment of
the inventive concept.
[0042] FIG. 3C is a schematic cross-sectional view partially
showing a display apparatus according to an exemplary embodiment of
the inventive concept.
[0043] FIG. 3D is a schematic cross-sectional view partially
showing a display apparatus according to an exemplary embodiment of
the inventive concept.
[0044] FIG. 4 is a schematic cross-sectional view partially showing
a display apparatus according to an exemplary embodiment of the
inventive concept.
[0045] FIG. 5A is a schematic cross-sectional view partially
showing a display apparatus according to an exemplary embodiment of
the inventive concept.
[0046] FIG. 5B is a schematic cross-sectional view partially
showing a display apparatus according to an exemplary embodiment of
the inventive concept.
[0047] FIG. 5C is a schematic cross-sectional view partially
showing a display apparatus according to an exemplary embodiment of
the inventive concept.
[0048] FIG. 5D is a schematic cross-sectional view partially
showing a display apparatus according to an exemplary embodiment of
the inventive concept.
[0049] FIG. 5E is a schematic cross-sectional view partially
showing a display apparatus according to an exemplary embodiment of
the inventive concept.
[0050] FIG. 6 is a schematic cross-sectional view partially showing
a display apparatus according to an exemplary embodiment of the
inventive concept.
[0051] FIG. 7 is a schematic cross-sectional view partially showing
a display apparatus according to an exemplary embodiment of the
inventive concept.
[0052] FIG. 8 is a schematic cross-sectional view partially showing
a display apparatus according to an exemplary embodiment of the
inventive concept.
[0053] FIG. 9A is a schematic plan view partially showing a display
apparatus according to an exemplary embodiment of the inventive
concept.
[0054] FIG. 9B is a schematic plan view partially showing a display
apparatus according to an exemplary embodiment of the inventive
concept.
[0055] FIG. 9C is a schematic plan view partially showing a display
apparatus according to an exemplary embodiment of the inventive
concept.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0056] Exemplary embodiments of the inventive concept will be
described more fully hereinafter with reference to the accompanying
drawings. Like reference numerals may refer to like elements
throughout the accompanying drawings.
[0057] As used herein, the term "and/or" includes any and all
combinations of one or more of the associated listed items.
[0058] Sizes and thicknesses of components in the drawings may be
exaggerated for convenience of explanation. In other words, the
inventive concept is not limited thereto.
[0059] In the examples described below, the x-axis, the y-axis, and
the z-axis are not limited to the three axes of the rectangular
coordinate system and may be interpreted in a broader sense. For
example, the x-axis, the y-axis, and the z-axis may be
perpendicular to one another or may represent different directions
that are not perpendicular to one another.
[0060] Exemplary embodiments of the inventive concept may be
implemented differently in that the process order may be different
from the described order. For example, two consecutively described
processes may be performed substantially at the same time or
performed in an order opposite to the described order.
[0061] A display apparatus is an apparatus displaying images, for
example, a liquid crystal display apparatus, an electrophoretic
display apparatus, an organic light-emitting display apparatus, an
inorganic light-emitting display apparatus, a field emission
display apparatus, a surface-conduction electron-emitter display
apparatus, a plasma display apparatus, a cathode ray display
apparatus, or the like.
[0062] Exemplary embodiments of the inventive concept provide for a
display apparatus capable of guaranteeing a longer lifespan thereof
and minimizing the occurrence of defects, such as disconnections,
during manufacturing processes.
[0063] Hereinafter, an organic light-emitting display apparatus
will be described as an example of the display apparatus according
to exemplary embodiments of the inventive concept. However, the
display apparatus according to the present inventive concept is not
limited thereto and may include various types of display
apparatuses.
[0064] FIG. 1 is a schematic perspective view partially showing a
display apparatus according to an exemplary embodiment of the
inventive concept, and FIG. 2 is a schematic cross-sectional view
partially showing the display apparatus of FIG. 1 according to an
exemplary embodiment of the inventive concept. In the display
apparatus according to the present exemplary embodiment, a
substrate 100 that is a part of the display apparatus is partially
bent as shown in FIG. 1, and thus, the display apparatus is also
partially bent because the substrate 100 is bent. However, FIG. 2
shows the display apparatus that is not bent, for convenience of
description. Other cross-sectional views and plan views according
to exemplary embodiments of the inventive concept, which will be
described below, also show display apparatuses that are not bent,
for convenience of description.
[0065] As shown in FIGS. 1 and 2, the substrate 100 includes a
bending area BA extending in a first direction (+y direction). The
bending area BA is located between a first area 1A and a second
area 2A, in a second direction (+x direction) that crosses the
first direction. In addition, as shown in FIG. 1, the substrate 100
is bent about a bending axis BAX extending in the first direction
(+y direction). The substrate 100 may include various materials
having flexible or bendable characteristics, for example, a polymer
resin such as polyethersulfone (PES), polyacrylate, polyetherimide
(PEI), polyethylene naphthalate (PEN), polyethylene terephthalate
(PET), polyphenylene sulfide (PPS), polyarylate (PAR), polyimide
(PI), polycarbonate (PC), or cellulose acetate propionate (CAP).
The substrate 100 may have a single-layer or multi-layer structure
including the above-described material, and the multi-layer
structure may further include an inorganic layer.
[0066] The first area 1A includes a display area DA. As shown in
FIG. 2, the first area 1A may also include a portion of a
non-display area outside the display area DA. The second area 2A
also includes the non-display area.
[0067] A plurality of pixels that display images may be provided in
the display area DA of the substrate 100. The display area DA may
include devices such as a display device 300, a thin film
transistor (TFT) 210, and a capacitor (Cst). The display area DA
may further include signal wirings such as a gate line through
which gate signals are transmitted, a data line through which data
signals are transmitted, a driving power line through which power
is transmitted, and a common power line. A pixel may be formed by
an electric coupling of the TFT 210, the capacitor, the display
device 300, and the like connected to the gate line, the data line,
and the driving power line, and the pixel may display an image. The
pixel may emit light at a brightness corresponding to driving
current passing through the display device 300 in response to the
data signals supplied to the pixel. The data signals may be
generated according to driving power and common power. The
plurality of pixels may be arranged in various ways, such as a
stripe layout, a PenTile layout, or the like.
[0068] In FIG. 2, the display device 300 in the display area DA may
be an organic light-emitting device. The organic light-emitting
device may be electrically connected to the TFT 210 via a pixel
electrode 310. If necessary, a separate TFT may be arranged on a
peripheral area outside the display area DA as well. The TFT
located on the peripheral area may be, for example, a part of a
circuit unit for controlling electric signals applied to the
display area DA.
[0069] The TFT 210 may include a semiconductor layer 211, a gate
electrode 213, a source electrode 215a, and a drain electrode 215b.
The semiconductor layer 211 may include amorphous silicon,
polycrystalline silicon, an oxide semiconductor, or an organic
semiconductor material.
[0070] The gate electrode 213 may be connected to a gate wiring
through which on and off signals are applied to the TFT 210. The
gate electrode 213 may include a low-resistive metallic material.
For example, the gate electrode 213 may have at least one layer
including a conductive material, e.g., molybdenum (Mo), aluminum
(Al), copper (Cu), and/or titanium (Ti).
[0071] Each of the source electrode 215a and the drain electrode
215b may have a single layer or multiple layers including a high
conductivity material. The source electrode 215a and the drain
electrode 215b may be connected to a source area and a drain area,
respectively, of the semiconductor layer 211. For example, each of
the source electrode 215a and the drain electrode 215b may have at
least one layer including a conductive material, e.g., Al, Cu,
and/or Ti.
[0072] The source electrode 215a and the drain electrode 215b may
be connected to the semiconductor layer 211 via contact holes C1
and C2. The contact holes C1 and C2 may be formed by simultaneously
etching an interlayer insulating layer 130 and a gate insulating
layer 120.
[0073] According to an exemplary embodiment of the inventive
concept, the TFT 210 is a top gate type TFT in which the gate
electrode 213 is above the semiconductor layer 211. However, the
inventive concept is not limited thereto. For example, the TFT 210
may be a bottom gate type TFT in which the gate electrode 213 is
under the semiconductor layer 211.
[0074] In order to ensure an insulating property between the
semiconductor layer 211 and the gate electrode 213, the gate
insulating layer 120, which includes an inorganic material such as
silicon oxide, silicon nitride, and/or silicon oxynitride, may be
arranged between the semiconductor layer 211 and the gate electrode
213. In addition, the interlayer insulating layer 130, which
includes an inorganic material such as silicon oxide, silicon
nitride, and/or silicon oxynitride, may be arranged on the gate
electrode 213, and the source electrode 215a and the drain
electrode 215b may be arranged on the interlayer insulating layer
130. The insulating layers that include inorganic material, as
described above, may be formed by chemical vapor deposition (CVD)
or atomic layer deposition (ALD). A similar process may be
performed with respect to exemplary embodiments described
below.
[0075] A buffer layer 110, including an inorganic material such as
silicon oxide, silicon nitride, and/or silicon oxynitride, may be
arranged between the TFT 210 and the substrate 100. The buffer
layer 110 may increase smoothness of an upper surface of the
substrate 100, or may prevent or reduce infiltration of impurities
into the semiconductor layer 211 from the substrate 100, etc. The
buffer layer 110 may include an inorganic material such as oxide or
nitride, an organic material, or an organic/inorganic composite
material, and may have a single-layer or multi-layer structure
including the inorganic material and/or the organic material.
According to exemplary embodiments of the inventive concept, the
buffer layer 110 may have a triple-layer structure of silicon
oxide/silicon nitride/silicon oxide.
[0076] In addition, a planarization layer 140 may be arranged on
the TFT 210. For example, when an organic light-emitting device is
arranged on the TFT 210 as shown in FIG. 2, the planarization layer
140 may planarize an upper portion of a protective layer that
covers the TFT 210. The planarization layer 140 may include an
organic material, for example, benzocyclobutene (BCB) or
hexamethyldisiloxane (HMDSO). Although the planarization layer 140
of FIG. 2 has a single-layer structure, the planarization layer 140
may have various modifications such as a multi-layer structure. In
addition, as shown in FIG. 2, the planarization layer 140 may have
an opening outside the display area DA so that a portion of the
planarization layer 140 in the display area DA and a portion of the
planarization layer 140 in the second area 2A may be physically
separate. Thus, impurities from the outside may not infiltrate into
the display area DA via the planarization layer 140.
[0077] In the display area DA of the substrate 100, an organic
light-emitting device (e.g., the display device 300) may be
disposed on the planarization layer 140. The organic light-emitting
device may include the pixel electrode 310, an opposite electrode
330, and an intermediate layer 320 that includes an organic
emission layer and is arranged between the pixel electrode 310 and
the opposite electrode 330. The pixel electrode 310 is electrically
connected to the TFT 210 by contacting one of the source electrode
215a and the drain electrode 215b via an opening formed in the
planarization layer 140, as shown in FIG. 2.
[0078] A pixel defining layer 150 may be arranged on the
planarization layer 140. The pixel defining layer 150 has an
opening corresponding to each of a plurality of sub-pixels, e.g.,
an opening exposing at least a center portion of the pixel
electrode 310, thus defining each pixel. Also, in FIG. 2, the pixel
defining layer 150 increases a distance between an edge of the
pixel electrode 310 and the opposite electrode 330 above the pixel
electrode 310 to prevent an arc from generating at the edge of the
pixel electrode 310. The pixel defining layer 150 may include, for
example, an organic material such as PI or HMDSO.
[0079] The intermediate layer 320 of the organic light-emitting
device may include a low-molecular weight material or a polymer
material. When the intermediate layer 320 includes the
low-molecular weight material, the intermediate layer 320 may have
a single or multi-layer structure including a hole injection layer
(HIL), a hole transport layer (HTL), an emission layer (EML), an
electron transport layer (ETL), and an electron injection layer
(EIL), and may include various organic materials such as copper
phthalocyanine (CuPc),
N,N'-Di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB), or
tris-8-hydroxyquinoline aluminum (Alq.sub.3). These layers may be
formed by a vacuum deposition method.
[0080] When the intermediate layer 320 includes the polymer
material, the intermediate layer 320 may have a structure mostly
including an HTL and an EML. In this regard, the HTL may include
PEDOT, and the EML may include polymer materials such as a
poly-phenylenevinylene (PPV)-based material and a
polyfluorene-based material. The intermediate layer 320 may be
formed by a screen printing method, an inkjet printing method, a
laser induced thermal imaging (LITI) method, or the like.
[0081] The intermediate layer 320 is not limited to the above
examples, and may have various other structures. In addition, the
intermediate layer 320 may include a layer that is integrally
formed throughout a plurality of pixel electrodes 310, or a layer
that is patterned to correspond to each of the plurality of pixel
electrodes 310.
[0082] The opposite electrode 330 is arranged over the display area
DA, and as shown in FIG. 2, the opposite electrode 330 may cover
the display area DA. In other words, the opposite electrode 330 may
be integrally formed with respect to a plurality of organic
light-emitting devices and thus may correspond to the plurality of
pixel electrodes 310.
[0083] Since the organic light-emitting device may be easily
damaged due to factors such as external moisture or oxygen, an
encapsulation layer 400 may cover and protect the organic
light-emitting device. The encapsulation layer 400 may cover the
display area DA and extend to the outside of the display area DA.
As shown in FIG. 2, the encapsulation layer 400 may include a first
inorganic encapsulation layer 410, an organic encapsulation layer
420, and a second inorganic encapsulation layer 430.
[0084] The first inorganic encapsulation layer 410 may cover the
opposite electrode 330, and may include silicon oxide, silicon
nitride, and/or silicon oxynitride. If necessary, other layers such
as a capping layer may be arranged between the first inorganic
encapsulation layer 410 and the opposite electrode 330. Since the
first inorganic encapsulation layer 410 is formed along the
opposite electrode 330, which is uneven, an upper surface of the
first inorganic encapsulation layer 410 is also uneven, as shown in
FIG. 2. The organic encapsulation layer 420 may cover the first
inorganic encapsulation layer 410, and unlike the first inorganic
encapsulation layer 410, an upper surface of the organic
encapsulation layer 420 may be roughly flat. In more detail, the
organic encapsulation layer 420 may have a roughly flat upper
surface at a portion corresponding to the display area DA. The
organic encapsulation layer 420 may include at least one material
selected from the group consisting of PET, PEN, PC, PI,
polyethylene sulfonate, polyoxymethylene, PAR, and HMDSO. The
second inorganic encapsulation layer 430 may cover the organic
encapsulation layer 420 and may include silicon oxide, silicon
nitride, and/or silicon oxynitride. Outside the display area DA, an
edge of the second inorganic encapsulation layer 430 may contact
the first inorganic encapsulation layer 410 so that the organic
encapsulation layer 420 is not externally exposed.
[0085] As described above, since the encapsulation layer 400
includes the first inorganic encapsulation layer 410, the organic
encapsulation layer 420, and the second inorganic encapsulation
layer 430, even when there is a crack in the encapsulation layer
400, the crack may not extend between the first inorganic
encapsulation layer 410 and the organic encapsulation layer 420 or
between the organic encapsulation layer 420 and the second
inorganic encapsulation layer 430, due to the above-described
multi-layered structure. Thus, formation of a path, through which
external moisture or oxygen may infiltrate into the display area
DA, may be prevented or reduced.
[0086] A polarization plate 520 may be attached to the
encapsulation layer 400 by an optically clear adhesive (OCA) 510.
The polarization plate 520 may reduce reflection of external light.
For example, when external light passes through the polarization
plate 520, it is reflected by an upper surface of the opposite
electrode 330 and then passes through the polarization plate 520
again. As such, a phase of the external light may be changed as the
external light passes through the polarization plate 520 twice. As
a result, a phase of reflected light is different from the phase of
the external light so that destructive interference occurs, and
accordingly, reflection of external light may be reduced and
visibility may be improved. The OCA 510 and the polarization plate
520 may cover the opening in the planarization layer 140, as shown
in FIG. 2. According to an exemplary embodiment of the inventive
concept, the display apparatus does not necessarily include the
polarization plate 520, and the polarization plate 520 may be
omitted or replaced with another configuration. For example, the
polarization plate 520 may be omitted, and instead, a black matrix
and a color filter may be used to reduce the reflection of external
light.
[0087] The buffer layer 110, the gate insulating layer 120, and the
interlayer insulating layer 130, all of which include an inorganic
material, may be referred to as an inorganic insulating layer. In
FIG. 2, the inorganic insulating layer has a flat upper surface at
an area overlapping with an organic material layer 160, which will
be described below.
[0088] The display apparatus may include a first conductive layer
215c arranged over the inorganic insulating layer, and the first
conductive layer 215c extends from the first area 1A toward the
second area 2A through the bending area BA. The first conductive
layer 215c may serve as a wiring via which electrical signals are
transmitted to the display area DA. The first conductive layer 215c
may be formed simultaneously with the source electrode 215a or the
drain electrode 215b and use the same material as that of the
source electrode 215a or the drain electrode 215b.
[0089] In addition, the display apparatus may include the organic
material layer 160, which is arranged between the inorganic
insulating material and the first conductive layer 215c and
includes a central portion 160a overlapping the bending area BA and
a peripheral portion 160b extending from the central portion 160a.
In other words, the peripheral portion 160b refers to an area that
does not overlap with the bending area BA. Also, an average
thickness <t1> of the central portion 160a of the organic
material layer 160 is greater than an average thickness <t2>
of the peripheral portion 160b. In this regard, the average
thickness <t1> of the central portion 160a may refer to a
value obtained by averaging thicknesses t1 of different sections of
the central portion 160a, and the average thickness <t2> of
the peripheral portion 160b may refer to a value obtained by
averaging thicknesses t2 of different sections of the peripheral
portion 160b.
[0090] The organic material layer 160 may overlap with the bending
area BA and may extend to a portion of the non-bending area. In
other words, the organic material layer 160 having a predetermined
width ORW may be formed on the inorganic insulating layer. In this
regard, the predetermined width ORW of the organic material layer
160 is illustrated in FIG. 2 as being defined by a distance between
boundaries at which an upper surface of the organic material layer
160 meets an upper surface of the inorganic insulating layer.
Referring to FIG. 2, the width ORW of the organic material layer
160 is greater than a width of the bending area BA.
[0091] As described above, although FIG. 2 shows that the display
apparatus is not bent for convenience of description, the display
apparatus according to the present exemplary embodiment is actually
in a state in which the substrate 100 is bent at the bending area
BA, as shown in FIG. 1. To achieve this, during manufacturing
processes, the display apparatus is manufactured in a state in
which the substrate 100 is roughly flat, as shown in FIG. 2, and
then, the substrate 100 is bent at the bending area BA so that the
display apparatus may roughly have the shape as shown in FIG. 1. In
this regard, although a tensile stress may be applied to the first
conductive layer 215c while the substrate 100 is bent at the
bending area BA, the display apparatus may prevent or reduce the
occurrence of defects in the first conductive layer 215c during the
bending process.
[0092] If the organic material layer 160 is not between the first
conductive layer 215c and the inorganic insulating layer and thus
the first conductive layer 215c is arranged on the inorganic
insulating layer in the bending area BA, a large tensile stress is
applied to the first conductive layer 215c when the substrate 100
is bent. The inorganic insulating layer has a higher hardness than
that of the organic material layer, and accordingly, cracks are
more likely to occur in the inorganic insulating layer at the
bending area BA. When cracks occur in the inorganic insulating
layer, the first conductive layer 215c disposed on the inorganic
insulating layer may also have cracks, and thus, there is a high
possibility of defects occurring, such as a disconnection in the
first conductive layer 215c.
[0093] However, in the display apparatus according to the present
exemplary embodiment, the organic material layer 160 is arranged
between the first conductive layer 215c and the inorganic
insulating layer in the bending area BA. The organic material layer
160 may buffer or absorb a tensile stress that the substrate 100
and the inorganic insulating layer are subjected to because of
bending, and may reduce the tensile stress transferred to the first
conductive layer 215c. Accordingly, the occurrence of cracks in a
portion of the first conductive layer 215c that corresponds to the
bending area BA may be prevented or reduced.
[0094] As illustrated in FIG. 2, the average thickness <t1>
of the central portion 160a of the organic material layer 160 is
greater than the average thickness <t2> of the peripheral
portion 160b of the organic material layer 160. The organic
material layer 160 may have the predetermined width ORW, and the
predetermined width ORW of the organic material layer 160 may be
greater than the width of the bending area BA. The organic material
layer 160 may have a shape with banks or slopes having a gentle
inclination (e.g., a bank shape).
[0095] According to exemplary embodiments of the inventive concept,
the central portion 160a of the organic material layer 160 may have
a substantially uniform thickness t1. The thickness t1 of the
central portion 160a may be set by taking into account the tensile
stress that is applied to the substrate 100 and the inorganic
insulating layer due to bending.
[0096] A thickness t2 of the peripheral portion 160b decreases in a
direction away from the central portion 160a (e.g., forming banks),
and thus, an upper surface of the peripheral portion 160b may have
a gentle inclination with respect to the upper surface of the
inorganic insulating layer. For example, FIG. 2 illustrates that at
least a portion of the peripheral portion 160b has a uniform
thickness t2, which is smaller than the thickness t1 of the central
portion 160a.
[0097] As described above, since the first conductive layer 215c
may include substantially the same material as those of the source
and drain electrodes 215a and 215b, and may be formed
simultaneously with the source and drain electrodes 215a and 215b.
In other words, a conductive layer may be formed on the entire
surface of the substrate 100 and then patterned to form the source
electrode 215a, the drain electrode 215b, and the first conductive
layer 215c.
[0098] The area where the upper surface of the inorganic insulating
layer and the upper surface of the organic material layer 160 meet
may define a boundary area. While the conductive layer is
patterned, if an inclination of the boundary area is relatively
steep (e.g., not gentle), conductive material may not be removed
and may remain on the boundary area. In this case, the remaining
conductive material may cause an electric short with other
conductive layers.
[0099] Accordingly, when the organic material layer 160 is formed,
the upper surface of the peripheral portion 160b having a gradual
or gentle inclination with respect to the upper surface of the
inorganic insulating layer may prevent such problems. When the
conductive layer is patterned to form the source electrode 215a,
the drain electrode 215b, and the first conductive layer 215c, the
remaining conductive material on the boundary area may be removed
effectively. In other words, the situation where conductive
material must be removed but instead remains may be effectively
prevented.
[0100] The organic material layer 160 may be formed by various
methods. For example, a photoresist material may be used to form
the organic material layer 160, and during manufacturing processes,
an exposure amount may be varied with respect to the central
portion 160a and the peripheral portion 160b of the organic
material layer 160 (that still has a roughly flat upper surface),
by using a slit mask, a half-tone mask, or the like so that a
certain portion may be etched (removed) relatively more than other
portions. Accordingly, thicknesses of the central portion 160a and
the peripheral portion 160b may be different from each other. Also,
the organic material layer 160 may be allowed to flow down through
a thermal reflow process, and thus, an inclination angle of an edge
area of the organic material layer 160 may be adjusted. The method
used when manufacturing the display apparatus is not limited to the
above example. For example, after forming the organic material
layer 160 having a roughly flat upper surface, only a certain
portion may be removed by a method such as dry etching, or other
various methods may be used. The organic material layer 160 may
include, for example, PI, acrylic, BCB, or HMDSO.
[0101] The display apparatus according to the present exemplary
embodiment may include second conductive layers 213a and 213b, in
addition to the first conductive layer 215c. The second conductive
layers 213a and 213b may be arranged on the first area 1A or the
second area 2A to be located at a different layer level from that
of the first conductive layer 215c, and may be electrically
connected to the first conductive layer 215c. In FIG. 2, the second
conductive layers 213a and 213b are located at the same layer level
as the gate electrode 213 of the TFT 210, e.g, on the gate
insulating layer 120, and include substantially the same material
as that of the gate electrode 213. In addition, the first
conductive layer 215c contacts the second conductive layers 213a
and 213b via contact holes formed in the interlayer insulating
layer 130. In addition, the second conductive layer 213a is located
in the first area 1A, and the second conductive layer 213b is
located in the second area 2A.
[0102] The second conductive layer 213a located in the first area
1A may be electrically connected to the TFT in the display area DA,
and thus, the first conductive layer 215c may be electrically
connected to the TFT via the second conductive layer 213a. The
second conductive layer 213b located in the second area 2A may also
be electrically connected to the TFT in the display area DA via the
first conductive layer 215c. As described above, the second
conductive layers 213a and 213b located outside the display area DA
may be electrically connected to components located in the display
area DA, or may extend toward the display area DA so as to be
located at least partially in the display area DA.
[0103] As described above, although FIG. 2 shows the display
apparatus that is not bent for convenience of description, the
display apparatus is actually in a state in which the substrate 100
is bent at the bending area BA, as shown in FIG. 1. To achieve
this, during manufacturing processes, the display apparatus is
manufactured in a state in which the substrate 100 is roughly flat,
as shown in FIG. 2, and then, the substrate 100 is bent at the
bending area BA so that the display apparatus may roughly have the
shape as shown in FIG. 1. In this regard, while the substrate 100
is bent at the bending area BA, a tensile stress may be applied to
components located in the bending area BA.
[0104] Accordingly, the first conductive layer 215c that extends
across the bending area BA may include a material having a high
elongation rate, and thus, the occurrence of a crack in the first
conductive layer 215c or a defect such as a disconnection in the
first conductive layer 215c may be prevented. In addition, the
second conductive layers 213a and 213b may include a material
having a lower elongation rate than that of the first conductive
layer 215c and electrical/physical characteristics different from
those of the first conductive layer 215c in the first area 1A or
the second area 2A. As such, efficiency of transmitting electrical
signals in the display apparatus may be improved, or a defect rate
during the manufacturing processes may be reduced. For example, the
second conductive layers 213a and 213b may include molybdenum, and
the first conductive layer 215c may include aluminum. The first
conductive layer 215c and the second conductive layers 213a and
213b may have multi-layer structures, if necessary.
[0105] Unlike the example shown in FIG. 2, an upper surface of the
second conductive layer 213b located in the second area 2A may not
be at least partially covered by the planarization layer 140, but
may be exposed to the outside, so as to be electrically connected
to various electronic devices or printed circuit boards.
[0106] A stress neutralization layer (SNL) 600 may be located
outside the display area DA. In other words, the SNL 600 may be
located over the first conductive layer 215c to correspond to at
least the bending area BA.
[0107] When a stack structure is bent, there is a stress neutral
plane in the stack structure. If there is no SNL 600, when the
substrate 100 is bent, an excessive tensile stress may be applied
to the first conductive layer 215c in the bending area BA because
the location of the first conductive layer 215c may not correspond
to the stress neutral plane. However, by forming the SNL 600 and
adjusting a thickness and a modulus of the SNL 600, the location of
the stress neutral plane in the stack structure, which includes the
substrate 100, the first conductive layer 215c, the SNL 600, and
the like, may be adjusted. Therefore, the stress neutral plane may
be adjusted to be located around the location of the first
conductive layer 215c, and thus, a tensile stress which is applied
to the first conductive layer 215c may be reduced.
[0108] The SNL 600 may extend to an end of the substrate 100 in the
display apparatus, unlike the example illustrated in FIG. 2. For
example, in the second area 2A, the first conductive layer 215c,
the second conductive layer 213b, and/or other conductive layers
electrically connected to the first and second conductive layers
215c and 213b may not be covered at least partially by the
interlayer insulating layer 130 or the planarization layer 140, but
may be electrically connected to various electronic devices or
printed circuit boards. Accordingly, the first conductive layer
215c, the second conductive layer 213b, and/or the other conductive
layers electrically connected to the first and second conductive
layers 215c and 213b may have portions that are electrically
connected to the various electronic devices or the printed circuit
boards. In this regard, since the electrically connected portions
need to be protected from impurities such as external moisture, the
SNL 600 may cover the electrically connected portions and thus
serve as a protective layer as well. For example, the SNL 600 may
extend to the end of the substrate 100 of the display
apparatus.
[0109] Although, in FIG. 2, an upper surface of the SNL 600 in a
direction toward the display area DA (-x direction) coincides with
an upper surface of the polarization plate 520 (in the +z
direction), the inventive concept is not limited thereto. For
example, an end of the SNL 600 in the direction toward the display
area DA (-x direction) may partially cover an upper surface at an
edge of the polarization plate 520. On the other hand, the end of
the SNL 600 in the direction toward the display area DA (-x
direction) may not contact the polarization plate 520 and/or a
light-transmitting adhesive (e.g., the OCA 510). In the latter
case, during or after formation of the SNL 600, degradation of the
display device 300 (e.g., an organic light-emitting device), due to
gas generated from the SNL 600 moving toward the display area DA
(-x direction), may be prevented.
[0110] As shown in FIG. 2, when the upper surface of the SNL 600 in
the direction toward the display area DA (-x direction) coincides
with the upper surface of the polarization plate 520 (in the +z
direction), the end of the SNL 600 in the direction toward the
display area DA (-x direction) partially covers the upper surface
at the edge of the polarization plate 520, or the end of the SNL
600 in the direction toward the display area DA (-x direction)
contacts the OCA 510, a portion of the SNL 600 in the direction
toward the display area DA (-x direction) may be thicker than other
portions of the SNL 600. Since a liquid phase material or a
paste-type material may be applied and hardened to form the SNL
600, the volume of the SNL 600 may be reduced during the hardening
process. In this regard, when the portion of the SNL 600 in the
direction toward the display area DA (-x direction) is in contact
with the polarization plate 520 and/or the OCA 510, that portion of
the SNL 600 is fixed at that location, and thus, volume reduction
occurs in the remaining portion of the SNL 600. As a result, the
portion of the SNL 600 in the direction toward the display area DA
(-x direction) may be thicker than the other portions of the SNL
600.
[0111] FIGS. 3A to 3D are each a cross-sectional view partially
showing a display apparatus according to exemplary embodiments of
the inventive concept. In detail, FIGS. 3A to 3D are each a
cross-sectional view schematically illustrating the bending area BA
and neighboring areas.
[0112] Referring to FIG. 3A, the predetermined width ORW of the
organic material layer 160 is greater than a width of the bending
area BA, and the organic material layer 160 has a bank shape having
a gentle inclination. The thickness t2 of the peripheral portion
160b of the organic material layer 160 may gradually decrease in a
direction away from the central portion 160a. Also, the thickness
t1 of the central portion 160a may gradually decrease in a
direction from the central area of the central portion 160a toward
the peripheral portion 160b. There may be various modifications,
such as, for example, the thickness t1 of the central portion 160a
may be substantially uniform, and only the thickness t2 of the
peripheral portion 160b gradually decreases in the direction away
from the central portion 160a. Accordingly, an upper surface of the
peripheral portion 160b may have a gentle inclination. According to
exemplary embodiments of the inventive concept, an angle between an
upper surface of the inorganic insulating layer and the upper
surface of the peripheral portion 160b may be less than or equal to
45 degrees.
[0113] The organic material layer 160 may be formed by various
methods. For example, a photoresist material may be used to form
the organic material layer 160, and during manufacturing processes,
an exposure amount may be varied with respect to the central
portion 160a and the peripheral portion 160b of the organic
material layer 160, which still has a roughly flat upper surface,
by using a slit mask, a half-tone mask, or the like so that a
certain portion may be etched (removed) relatively more than other
portions. Accordingly, thicknesses of the central portion 160a
and/or the peripheral portion 160b may gradually change. Also, the
organic material layer 160 may be allowed to flow down through a
thermal reflow process, and thus, an inclination angle of an edge
area of the organic material layer 160 may be adjusted.
[0114] As described above, the upper surface of the peripheral
portion 160b may have a gentle inclination, and thus, when a
conductive layer is patterned in order to form the first conductive
layer 215c, remaining conductive material may be removed
effectively.
[0115] Referring to FIG. 3B, the organic material layer 160 may
have a stacked (or stack) structure including a first organic
material layer 161 having a first width ORW1 and a second inorganic
material layer 163 having a second width ORW2 smaller than the
first width ORW1. In this regard, the second width ORW2 may be
greater than a width of the bending area BA. Thus, the central
portion 160a may have a substantially uniform thickness t1, and the
first organic material layer 161 and the second organic material
layer 163 may have a step, and accordingly, an upper surface of the
peripheral portion 160b may have a gentle inclination. Although
FIG. 3B illustrates an example in which the organic material layer
160 includes two layers, the inventive concept is not limited
thereto. Alternatively, the organic material layer 160 may include
a plurality of layers having different widths which are stacked on
each other so that the upper surface of the peripheral portion 160b
may have a gentle inclination. According to exemplary embodiments
of the inventive concept, the upper surface of the peripheral
portion 160b may have an inclination of about 45 degrees or less
with respect to an upper surface of the inorganic insulating
layer.
[0116] As described above, the upper surface of the peripheral
portion 160b may have a gentle inclination, and thus, when a
conductive layer is patterned in order to form the first conductive
layer 215c, the remaining conductive material may be removed
effectively.
[0117] Referring to FIGS. 3C and 3D, the organic material layer 160
may have an uneven surface 160s at least partially in an upper
surface thereof (in the +z direction). FIG. 3C illustrates an
example in which the uneven surface 160s is formed only in the
central portion 160a of the organic material layer 160. FIG. 3D
illustrates an example in which the uneven surface 160s is formed
over the entire upper surface of the organic material layer 160. An
area where the uneven surface 160s is formed may be variously
modified.
[0118] Since the organic material layer 160 includes the uneven
surface 160s, the first conductive layer 215c located on the
organic material layer 160 may have an upper surface and/or a lower
surface having a shape corresponding to the uneven surface 160s of
the organic material layer 160.
[0119] As described above, since tensile stress may be applied to
the first conductive layer 215c when the substrate 100 is bent at
the bending area BA during the manufacturing processes, when the
upper surface and/or the lower surface of the first conductive
layer 215c has the shape corresponding to the uneven surface 160s
of the organic material layer 160, the amount of tensile stress
which is applied to the first conductive layer 215c may be reduced.
In other words, the tensile stress that may be generated during the
bending process may be reduced via deformation of the shape of the
organic material layer 160 having lower hardness. In this regard,
the first conductive layer 215c having the uneven shape before the
bending process may be transformed to correspond to the shape of
the organic material layer 160, which is deformed due to the
bending process, and thus, occurrence of a defect, such as a
disconnection in the first conductive layer 215c, may be prevented
effectively.
[0120] Also, the uneven surface 160s may be formed at least
partially in the upper surface of the organic material layer 160
(in the +z direction), and thus, a surface area of the upper
surface of the organic material layer 160 and a surface area of the
upper and lower surfaces of the first conductive layer 215c may be
increased. Large surface areas of the upper surface of the organic
material layer 160 and the upper and lower surfaces of the first
conductive layer 215c may denote that a deformation margin is large
enough to reduce the tensile stress caused by the bending of the
substrate 100.
[0121] Since the first conductive layer 215c is located on the
organic material layer 160, the lower surface of the first
conductive layer 215c has a shape corresponding to the uneven
surface 160s of the organic material layer 160. However, the upper
surface of the first conductive layer 215c may have an uneven
surface that has a shape independent of the shape of the uneven
surface 160s of the organic material layer 160.
[0122] For example, after forming a conductive material layer on
the organic material layer 160, a photoresist is applied on the
conductive material layer and the photoresist is developed while
varying an exposure amount, according to locations on the
photoresist, by using a slit mask, a half-tone mask, or the like.
Accordingly, the conductive material layer exposed due to the
developing of the photoresist is etched, the photoresist is
removed, and thus, the first conductive layer 215c is formed. Since
the exposure amount is varied according to the locations on the
photoresist by using the slit mask, the half-tone mask, or the
like, the degree of etching of the conductive material layer may
vary according to locations on the conductive material layer. Thus,
an uneven surface may be artificially formed on the upper surface
of the first conductive layer 215c, and in this case, the upper
surface of the first conductive layer 215c may have the uneven
surface that has a shape independent of the shape of the uneven
surface 160s of the organic material layer 160. A similar process
may be performed with respect to exemplary embodiments described
below. Even when the process of artificially forming the uneven
surface on the upper surface of the first conductive layer 215c is
performed as described above, the uneven surface on the upper
surface of the first conductive layer 215c may still correspond to
the uneven surface 160s of the organic material layer 160.
[0123] FIG. 4 is a schematic cross-sectional view partially showing
a display apparatus according to an exemplary embodiment of the
inventive concept. Although the inorganic insulating layer has been
described so far as having a flat upper surface in an area
overlapping with an organic insulating layer, the inventive concept
is not limited thereto. For example, as illustrated in FIG. 4, the
inorganic insulating layer may include a groove at a location
corresponding to the bending area BA.
[0124] Referring to FIG. 4, the buffer layer 110 may be
continuously formed throughout the first area 1A, the bending area
BA, and the second area 2A. In addition, the gate insulating layer
120 may have an opening 120a corresponding to the bending area BA,
and the interlayer insulating layer 130 may also have an opening
130a corresponding to the bending area BA. Accordingly, the
inorganic insulating layer, which includes the buffer layer 110,
the gate insulating layer 120, and the interlayer insulating layer
130, may be construed as having a groove corresponding to the
bending area BA. Alternatively, the inorganic insulating layer may
include a groove of a different type. There may be various
modifications, such as, for example, an upper surface of the buffer
layer 110 (in the +z direction) may be partially removed, or a
lower surface of the gate insulating layer 120 (in -z direction)
may not be removed but may remain. Formation of the groove may
occur simultaneously with a patterning process for forming the
contact holes C1 and C2 for connecting the source electrode 215a
and the drain electrode 215b of the TFT 210 to the semiconductor
layer 211.
[0125] The groove corresponding to the bending area BA may denote
that the groove overlaps with the bending area BA. In this regard,
an area of the groove may be greater than that of the bending area
BA. To achieve this, a width GW of the groove is greater than a
width of the bending area BA, as shown in FIG. 4. In this regard,
the area of the groove may be defined as an area where the opening
(among the openings 120a and 130a) is smallest. In FIG. 4, the area
of the groove is defined by the area of the opening 120a in the
gate insulating layer 120.
[0126] In the display apparatus according to the present exemplary
embodiment, the organic material layer 160 is arranged between the
inorganic insulating layer and the first conductive layer 215c, and
includes the central portion 160a overlapping with the bending area
BA and the peripheral portion 160b extending from the central
portion 160a. In other words, the peripheral portion 160b refers to
an area that does not overlap with the bending area BA. Also, the
average thickness <t1> of the central portion 160a of the
organic material layer 160 is greater than the average thickness
<t2> of the peripheral portion 160b. Since the groove
overlaps with the bending area BA, the organic material layer 160
fills the groove. Because the organic material layer 160 fills the
groove, although the average thickness <t1> of the central
portion 160a is greater than the average thickness <t2> of
the peripheral portion 160b, a height h1 of the central portion
160a from an upper surface of the substrate 100 may be less than a
height h2 of the peripheral portion 160b from the upper surface of
the substrate 100.
[0127] Although FIG. 4 shows that the display apparatus is not bent
for convenience of description, the display apparatus is actually
in a state in which the substrate 100 is bent at the bending area
BA, as shown in FIG. 1. To achieve this, during manufacturing
processes, the display apparatus is manufactured in a state in
which the substrate 100 is roughly flat, as shown in FIG. 4, and
then, the substrate 100 is bent at the bending area BA so that the
display apparatus may roughly have the shape as shown in FIG. 1. In
this regard, tensile stress may be applied to the first conductive
layer 215c while the substrate 100 is bent at the bending area BA,
but in the display apparatus according to the present exemplary
embodiment, the inorganic insulating layer has a groove in the
bending area BA, and a portion of the first conductive layer 215c
that corresponds to the bending area BA is located on the organic
material layer 160 that at least partially fills the groove in the
inorganic insulating layer. Accordingly, the occurrence of cracks
in the portion of the first conductive layer 215c that corresponds
to the bending area BA may be prevented or reduced.
[0128] Since the inorganic insulating layer has a higher hardness
than the organic material layer 160, the inorganic insulating layer
in the bending area BA is more likely to have cracks. When the
inorganic insulating layer cracks, there is a high possibility that
the cracks may spread to the first conductive layer 215c. Although
the organic material layer 160 may block the cracks from spreading,
the groove formed in the inorganic insulating layer may further
reduce the possibility of the inorganic insulating layer having
cracks. Therefore, less tensile stress may be concentrated on the
first conductive layer 215c.
[0129] As shown in FIG. 4, the organic material layer 160 may cover
an inner surface of the groove in the inorganic insulating layer.
Various wirings of the display apparatus may be formed by forming a
conductive material layer on the entire surface of the substrate
100 and then patterning the conductive material layer. If the
organic material layer 160 does not cover an inner surface of the
opening 120a of the gate insulating layer 120 or an inner surface
of the opening 130a of the interlayer insulating layer 130 (e.g.,
the groove), during the patterning of the conductive material
layer, conductive material may not be removed but may remain on the
inner surface of the opening 120a or the opening 130a. In this
case, the remaining conductive material may cause an electric short
with other conductive layers. Therefore, the organic material layer
160 covering the inner surface of the groove may prevent this.
[0130] The height h1 of the central portion 160a of the organic
material layer 160 from the upper surface of the substrate 100 may
be greater than a height H of the inorganic insulating layer from
the upper surface of the substrate 100. In this case, the thickness
t2 of the peripheral portion 160b may be adjusted so that an upper
surface of the peripheral portion 160b may have a gentle
inclination with respect to an upper surface of the inorganic
insulating layer. As shown in FIG. 2, the thickness t2 of the
peripheral portion 160b decreases in a direction away from the
central portion 160a. Also, at least a portion of the peripheral
portion 160b may have a uniform thickness t2, which is smaller than
the thickness t1 of the central portion 160a. According to
exemplary embodiments of the inventive concept, an angle between
the upper surface of the peripheral portion 160b and the upper
surface of the inorganic insulating layer may be within 45
degrees.
[0131] As described above, since the first conductive layer 215c
may include substantially the same material as that of the source
and drain electrodes 215a and 215b and may be formed simultaneously
with the source and drain electrodes 215a and 215b, a conductive
layer may be formed on the entire surface of the substrate 100 and
then patterned to form the source electrode 215a, the drain
electrode 215b, and the first conductive layer 215c. When an
inclination of a boundary area, where the upper surface of the
inorganic insulating layer and an upper surface of the organic
material layer 160 meet, is not gentle, conductive material may not
be removed from the boundary area while the conductive layer is
patterned and may remain on the boundary area. In this case, the
remaining conductive material may cause an electric short with
other conductive layers.
[0132] Accordingly, when the organic material layer 160 is formed,
the upper surface of the peripheral portion 160b may have a gentle
inclination with respect to the upper surface of the inorganic
insulating layer. Thus, when the conductive layer is patterned in
order to form the source electrode 215a, the drain electrode 215b,
and the first conductive layer 215c, the remaining conductive
material may be removed effectively.
[0133] FIGS. 5A to 5D are each a cross-sectional view partially
showing a display apparatus according to exemplary embodiments of
the inventive concept. In detail, FIGS. 5A to 5D are each a
cross-sectional view schematically illustrating the bending area BA
and neighboring areas.
[0134] Referring to FIG. 5A, as the height h1 of the central
portion 160a of the organic material layer 160 from an upper
surface of the substrate 100 is greater than the height H of the
inorganic insulating layer from the upper surface of the substrate
100, the organic material layer 160 is generally higher than an
upper surface of the inorganic insulating layer. In other words,
the organic material layer 160 has a bank shape having a gentle
inclination.
[0135] The height h2 of the peripheral portion 160b of the organic
material layer 160 from the upper surface of the substrate 100 may
gradually decrease in a direction away from the central portion
160a. Also, the height h1 may gradually decrease in a direction
from the central area of the center portion 160a to the peripheral
portion 160b. There may be various modifications, such as, for
example, the thickness t1 of the central portion 160a may be
substantially uniform, and only the thickness t2 of the peripheral
portion 160b gradually decreases in the direction away from the
central portion 160a. Accordingly, an upper surface of the
peripheral portion 160b may have a gentle inclination with respect
to the upper surface of the inorganic insulating layer. According
to exemplary embodiments of the inventive concept, an angle between
the upper surface of the inorganic insulating layer and the upper
surface of the peripheral portion 160b may be less than or equal to
45 degrees.
[0136] The organic material layer 160 may be formed by various
methods. For example, a photoresist material may be used to form
the organic material layer 160, and during manufacturing processes,
an exposure amount may be varied with respect to the central
portion 160a and the peripheral portion 160b of the organic
material layer 160, which still has a roughly flat upper surface,
by using a slit mask, a half-tone mask, or the like, so that a
certain portion may be etched (removed) relatively more than other
portions. Accordingly, heights of the central portion 160a and/or
the peripheral portion 160b may gradually change. Also, the organic
material layer 160 may be allowed to flow down through a thermal
reflow process, and thus, an inclination angle of an edge area of
the organic material layer 160 may be adjusted.
[0137] As described above, the upper surface of the peripheral
portion 160b may have a gentle inclination with respect to the
upper surface of the inorganic insulating layer, and thus, when a
conductive layer is patterned in order to form the first conductive
layer 215c, the remaining conductive material may be removed
effectively.
[0138] Referring to FIG. 5B, the height h1 of the central portion
160a of the organic material layer 160 from an upper surface of the
substrate 100 may be less than the height H of the inorganic
insulating layer from the upper surface of the substrate 100. Also,
the peripheral portion 160b may cover an inner surface of a groove
and extend to an upper surface of the inorganic insulating layer.
Although, in a portion where the peripheral portion 160b covers the
inner surface of the groove or a portion where the peripheral
portion 160b is on the upper surface of the inorganic insulating
layer, the height h2 of the peripheral portion 160b from the upper
surface of the substrate 100 may be greater than the height h1, the
thickness t2 of the peripheral portion 160b may nevertheless
decrease in a direction away from the central portion 160a.
[0139] Accordingly, an upper surface of the peripheral portion 160b
may have a gentle inclination with respect to the upper surface of
the inorganic insulating layer. According to exemplary embodiments
of the inventive concept, an angle between the upper surface of the
inorganic insulating layer and the upper surface of the peripheral
portion 160b may be less than or equal to 45 degrees.
[0140] As described above, the upper surface of the peripheral
portion 160b may have a gentle inclination with respect to the
upper surface of the inorganic insulating layer, and thus, when a
conductive layer is patterned to form the first conductive layer
215c, the remaining conductive material may be removed
effectively.
[0141] Referring to FIGS. 5C and 5D, the organic material layer 160
may have the uneven surface 160s at least partially in an upper
surface thereof (in the +z direction). FIG. 5C illustrates an
example in which the uneven surface 160s is formed only in the
central portion 160a of the organic material layer 160. FIG. 5D
illustrates an example in which the uneven surface 160s is formed
mainly in the central portion 160a so that an area of the uneven
surface 160s may be greater than an area of the central portion
160a. In FIG. 5D, a width UEW of the uneven surface 160s is greater
than a width of the bending area BA. The area where the uneven
surface 160s is formed may be variously modified. For example, the
uneven surface 160s may be formed over the entire upper surface of
the organic material layer 160.
[0142] Since the organic material layer 160 includes the uneven
surface 160s, the first conductive layer 215c located on the
organic material layer 160 may have an upper surface and/or a lower
surface having a shape corresponding to the uneven surface 160s of
the organic material layer 160.
[0143] As described above, since tensile stress may be applied to
the first conductive layer 215c when the substrate 100 is bent at
the bending area BA during the manufacturing processes, when the
upper surface and/or the lower surface of the first conductive
layer 215c has the shape corresponding to the uneven surface 160s,
the amount of tensile stress applied to the first conductive layer
215c may be reduced. In other words, the tensile stress that may be
generated during the bending process may be reduced via deformation
of the shape of the organic material layer 160 having a lower
hardness. In this regard, the first conductive layer 215c having
the uneven shape before the bending process may be transformed to
correspond to the shape of the organic material layer 160, which is
deformed due to the bending process, and thus, the occurrence of a
defect, such as a disconnection in the first conductive layer 215c,
may be effectively prevented.
[0144] Also, the uneven surface 160s is formed at least partially
in the upper surface of the organic material layer 160 (in the +z
direction), and thus, a surface area of the upper surface of the
organic material layer 160 and a surface area of the upper and
lower surfaces of the first conductive layer 215c may be increased.
Large surface areas of the upper surface of the organic material
layer 160 and the upper and lower surfaces of the first conductive
layer 215c may denote that a deformation margin is large enough to
reduce the tensile stress caused by bending of the substrate
100.
[0145] Since the first conductive layer 215c is located on the
organic material layer 160, the lower surface of the first
conductive layer 215c has a shape corresponding to the uneven
surface 160s of the organic material layer 160. However, the upper
surface of the first conductive layer 215c may have an uneven
surface that has a shape independent of the shape of the uneven
surface 160s.
[0146] Referring to FIG. 5E, the buffer layer 110 may include a
stack structure including a first buffer layer 111 and a second
buffer layer 112. Also, the first buffer layer 111 may continuously
extend over the first area 1A, the bending area BA, and the second
area 2A. An upper surface of the second buffer layer 112 (in the +z
direction) may be partially removed from the bending area BA. In
addition, the gate insulating layer 120 may have the opening 120a
corresponding to the bending area BA, and the interlayer insulating
layer 130 may also have the opening 130a corresponding to the
bending area BA. Accordingly, the inorganic insulating layer,
including the buffer layer 110, the gate insulating layer 120, and
the interlayer insulating layer 130, may be construed as having a
groove corresponding to the bending area BA.
[0147] The above-described structure may allow a portion of the
second buffer layer 112 to also be etched in an etching process
during which the openings 120a and 130a are formed in the gate
insulating layer 120 and the interlayer insulating layer 130,
respectively.
[0148] According to exemplary embodiments of the inventive concept,
the inorganic insulating layer may include a groove of a different
type. There may be various modifications, for example, a lower
surface of the gate insulating layer 120 (in the -z direction) may
not be removed, but may remain. Formation of the groove may occur
simultaneously with a patterning process for forming the contact
holes C1 and C2 for connecting the source electrode 215a and the
drain electrode 215b of the TFT 210 to the semiconductor layer
211.
[0149] With respect to the exemplary embodiments described below,
for convenience of description, the inorganic insulating layer has
a flat upper surface in an area overlapping with the organic
material layer 160. However, the exemplary embodiments may instead
have the inorganic insulating layer with a groove, as described
above.
[0150] FIG. 6 is a schematic cross-sectional view partially showing
a display apparatus according to an exemplary embodiment of the
inventive concept. Referring to FIG. 6, the display apparatus may
further include a protective film 170 for protecting the substrate
100. The protective film 170 is a lower protective film for
protecting a lower surface of the substrate 100, and as shown in
FIG. 6, the protective film 170 may include an opening 170OP. The
opening 170OP corresponds to the bending area BA, and an area of
the opening 170OP may be greater than an area of the bending area
BA. In FIG. 6, a width of the opening 170OP is greater than a width
of the bending area BA.
[0151] Since the protective film 170 protects the lower surface of
the substrate 100, the protective film 170 may have its own
strength. Accordingly, when the protective film 170 has a low level
of flexibility, the protective film 170 may be isolated or
separated from the substrate 100 when the substrate 100 is bent.
Therefore, as shown in FIG. 6, when the protective film 170
includes the opening 170OP corresponding to the bending area BA,
the occurrence of such isolation between the protective film 170
and the substrate 100 may be effectively prevented. Consequently,
as described above, the area of the opening 170OP in the protective
film 170 is greater than the area of the bending area BA to prevent
the isolation.
[0152] However, considering that the protective film 170 has to
protect the lower surface of the substrate 100 as much as possible,
the area of the opening 170OP in the protective film 170 may need
to be reduced. Therefore, the area of the opening 170OP in the
protective film 170 may be greater than the area of the bending
area BA, but may be smaller than an area of the organic material
layer 160. Thus, in FIG. 6, the width of the opening 170OP is
greater than the width of the bending area BA, but is smaller than
the predetermined width ORW of the organic material layer 160. The
protective film 170 having the above-described shape may be applied
to the display apparatuses of the exemplary embodiments described
above and below.
[0153] If necessary, unlike the protective film 170 shown in FIG.
6, the protective film 170 may not cover an edge of the substrate
100. In other words, the protective film 170 may not be in the
second area 2A.
[0154] In the exemplary embodiments described above, the first
conductive layer 215c is formed of substantially the same material
as that of the source or drain electrode 215a or 215b of the TFT
210 at substantially the same time. However, the inventive concept
is not limited thereto.
[0155] For example, as shown in FIG. 7, which is a schematic
cross-sectional view partially showing a display apparatus
according to an exemplary embodiment of the inventive concept, a
touch electrode 710 having various patterns may be located above
the encapsulation layer 400 for implementing a touchscreen
function. When the touch electrode 710 is formed, the first
conductive layer 215c may be simultaneously formed by using
substantially the same material as that of the touch electrode 710.
Also, when a touch protective layer 720 for protecting the touch
electrode 710 is formed, a protective layer covering the first
conductive layer 215c may be simultaneously formed. If necessary,
the touch protective layer 720 may integrally extend from the
display area DA to at least the bending area BA, as shown in FIG.
7. The formation of the first conductive layer 215c simultaneously
with the touch electrode 710 may be applied to the display
apparatuses of the exemplary embodiments described above or below.
Unlike the above example, the first conductive layer 215c may
instead be formed simultaneously with the opposite electrode 330 by
using substantially the same material as that of the opposite
electrode 330.
[0156] In this case, when an organic material layer which is
included in the display area DA is formed, the organic material
layer 160 may be formed using substantially the same material as
that of the organic material layer in the display area DA. For
example, when the planarization layer 140 is formed using an
organic material, the organic material layer 160 may be formed
simultaneously with the planarization layer 140 by using
substantially the same material as that of the planarization layer
140. As another example, the organic material layer 160 may be
formed simultaneously with the pixel defining layer 150 by using
substantially the same material as that of the pixel defining layer
150. As another example, the organic material layer 160 may be
formed simultaneously with the organic encapsulation layer 420 of
the encapsulation layer 400 by using substantially the same
material as that of the organic encapsulation layer 420 of the
encapsulation layer 400.
[0157] In addition, there may be various modifications, for
example, when the interlayer insulating layer 130 is formed using
an insulating organic material, the organic material layer 160 may
be formed simultaneously with the interlayer insulating layer 130
by using substantially the same material as that of the interlayer
insulating layer 130. If necessary, the organic material layer 160
may be formed by a separate process regardless of the planarization
layer 140.
[0158] The formation of the organic material layer 160
simultaneously with the organic material layer which is included in
the display area DA by using substantially the same material as
that of the organic material layer may be similarly applied to the
display apparatuses of exemplary embodiments described above or
below.
[0159] In this regard, the first conductive layer 215c may be
formed simultaneously with the touch electrode 710 by using
substantially the same material as that of the touch electrode 710,
as described above. In this case, the touch protective layer 720
may cover the first conductive layer 215c. Alternatively, in
addition to the touch protective layer 720, another organic
insulating layer may be needed for the touchscreen function. For
example, another additional touch electrode may be present in
addition to the touch electrode 710, and an organic insulating
layer may be between the touch electrode 710 and the other
additional touch electrode. In this case, the organic insulating
layer may extend and cover the first conductive layer 215c, or a
layer which is formed simultaneously with the organic insulating
layer by using substantially the same material as that of the
organic insulating layer may cover the first conductive layer
215c.
[0160] There may be various modifications, for example, the first
conductive layer 215c may be formed simultaneously with the source
electrode 215a or the drain electrode 215b by using substantially
the same material as that of the source electrode 215a or the drain
electrode 215b, rather than the touch electrode 710. In this case,
the first conductive layer 215c may be covered by the planarization
layer 140 or another insulating layer.
[0161] FIG. 8 is a schematic cross-sectional view partially showing
a display apparatus according to an exemplary embodiment of the
inventive concept. Referring to FIG. 8, the substrate 100 of the
display apparatus may have a multi-layer structure. The substrate
100 may include a stack structure including a first resin layer
101, a barrier layer 102, an intermediate layer 103, and a second
resin layer 104.
[0162] The first resin layer 101 and the second resin layer 104 may
each include a polymer resin such as PES, polyacrylate, PEI, PEN,
PET, PPS, PAR, PI, PC, or CAP.
[0163] The barrier layer 102 may be disposed between the first
resin layer 101 and the second resin layer 104 to prevent
penetration of moisture or oxygen. The barrier layer 102 may
include an inorganic material such as metal oxide, silicon nitride,
or silicon oxide. The barrier layer 102 may include a single-layer
film or may include multi-layer films stacked on each other.
[0164] The intermediate layer 103 may be disposed between the
barrier layer 102 and the second resin layer 104 to strengthen
adhesion between the barrier layer 102 and the second resin layer
104. The intermediate layer 103 may include an amorphous material
such as amorphous silicon, indium tin oxide (ITO), Al, Ti and/or
Mo. However, the material of the intermediate layer 103 is not
limited thereto, and any material that may strengthen adhesion
between the barrier layer 102 and the second resin layer 104 may be
used to form the intermediate layer 103. In addition, if necessary,
the substrate 100 may include additional resin layers, barrier
layers, and intermediate layers.
[0165] As described above, when the substrate 100 has a multi-layer
structure, a penetration path of moisture or oxygen may be more
efficiently blocked compared to when the substrate 100 has a
single-layer structure, and thus, the occurrence of defects in the
display device 300 may be prevented or reduced. Also, the substrate
100 according to the present exemplary embodiment may employ the
intermediate layer 103 to prevent exfoliation between the barrier
layer 102 and the second resin layer 104. In the exemplary
embodiments that have been described above, the first conductive
layer 215c may extend in the second direction (+x direction) and
cross the first direction (+y direction) in which a protrusion of
the uneven surface 160s of the upper surface of the organic
material layer 160 extends. The cross angle may be 90 degrees as
shown in FIG. 9A, which is a conceptual plan view partially showing
a display apparatus according to an exemplary embodiment of the
inventive concept, or may not be 90 degrees as shown in FIG. 9B.
Reference numeral GD of FIGS. 9A and 9B denotes a direction in
which the uneven surface 160s of the upper surface of the organic
material layer 160 extends. Although the direction in which the
uneven surface 160s extends is shown in FIG. 9B to be inclined with
respect to the second direction (+x direction), as opposed to FIG.
9A, the inventive concept is not limited thereto. For example, the
direction in which the uneven surface 160s extends may be the first
direction (+y direction), and an extension direction of the first
conductive layer 215c may not be the second direction (+x
direction) but a direction inclined with respect to the second
direction (+x direction) (for example, a direction having an angle
of 45 degrees with respect to the second direction (+x direction)).
When a plurality of first conductive layers 215c is present, an
angle of some of the plurality of first conductive layers 215c with
respect to the second direction (+x direction) may be different
from an angle of the remaining of the plurality of first conductive
layers 215c with respect to the second direction (+x
direction).
[0166] In addition, although, in FIGS. 9A and 9B, the first
conductive layer 215c extends straight in the second direction (+x
direction), the inventive concept is not limited thereto. There may
be various modifications, for example, as shown in FIG. 9C, the
first conductive layer 215c may zigzag left and right or may be
wavy on a plane where the first direction (+y direction) and the
second direction (+x direction) cross each other (an xy plane).
[0167] According to the exemplary embodiments of the inventive
concept described above, a longer lifespan of a display apparatus
may be guaranteed, and the occurrence of defects, such as
disconnection, may be reduced when manufacturing the display
apparatus.
[0168] While the inventive concept has been shown and described
with reference to exemplary embodiments thereof, it will be
understood by those of ordinary skill in the art that various
changes in form and details may be made thereto without departing
from the spirit and scope of the present inventive concept as
defined by the following claims.
* * * * *