U.S. patent application number 15/490192 was filed with the patent office on 2017-08-03 for flexible display having damage impeding layer and method for manufacturing the same.
The applicant listed for this patent is Samsung Display Co., Ltd.. Invention is credited to Dae-Yong KIM, Joo-Hwa LEE, Suk-Beom YOU.
Application Number | 20170222192 15/490192 |
Document ID | / |
Family ID | 51266240 |
Filed Date | 2017-08-03 |
United States Patent
Application |
20170222192 |
Kind Code |
A1 |
YOU; Suk-Beom ; et
al. |
August 3, 2017 |
FLEXIBLE DISPLAY HAVING DAMAGE IMPEDING LAYER AND METHOD FOR
MANUFACTURING THE SAME
Abstract
A flexible display includes a flexible base substrate, a thin
film transistors layer formed on the flexible base substrate, and a
light emitting elements layer formed on the thin film transistors
layer, where the flexible base substrate includes a first support
layer formed below the thin film transistors layer, a second
support layer disposed below the first support layer, and a
heat-energy blocking/reflecting layer provided between the first
support layer and the second support layer. The heat-energy
blocking/reflecting layer is configured to block or reflect a
sufficient portion of radiated heat-energy that is generated when
the flexible base substrate is separated from a supporting carrier
substrate so as to prevent the damage from the radiated heat-energy
to the light emitting elements layer.
Inventors: |
YOU; Suk-Beom; (Yongin-Si,
KR) ; KIM; Dae-Yong; (Yongin-Si, KR) ; LEE;
Joo-Hwa; (Yongin-Si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Display Co., Ltd. |
Yongin-si |
|
KR |
|
|
Family ID: |
51266240 |
Appl. No.: |
15/490192 |
Filed: |
April 18, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14293947 |
Jun 2, 2014 |
9653481 |
|
|
15490192 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02E 10/549 20130101;
Y02P 70/50 20151101; H01L 27/3262 20130101; H01L 27/1214 20130101;
H01L 51/5259 20130101; H01L 27/3244 20130101; H01L 51/5253
20130101; H01L 51/529 20130101; Y02P 70/521 20151101; H01L 27/1259
20130101; H01L 51/56 20130101; H01L 51/5256 20130101; H01L 51/5271
20130101; H01L 2227/326 20130101; H01L 51/0097 20130101; H01L
2251/5338 20130101 |
International
Class: |
H01L 51/56 20060101
H01L051/56; H01L 51/00 20060101 H01L051/00; H01L 27/32 20060101
H01L027/32; H01L 51/52 20060101 H01L051/52 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 8, 2013 |
KR |
10-2013-0094272 |
Claims
1. A method of manufacturing a flexible display device, the method
comprising: adhering a base flexible substrate layer to and on a
carrier substrate; disposing on the base flexible substrate layer,
a flexible heat-energy blocking/reflecting layer; disposing above
the heat-energy blocking/reflecting layer, a further layer of the
flexible display device that can be damaged by exposure to an
excessive amount of radiated heat-energy; and after disposing the
further layer that can be damaged by exposure to said excessive
amount of radiated heat-energy, separating the base flexible
substrate layer from the carrier substrate by using a separation
process that generates radiated heat-energy where the radiated
heat-energy can result in the excessive amount of radiated
heat-energy that damages the further layer that can be damaged by
exposure to said excessive amount of radiated heat-energy; wherein
the heat-energy blocking/reflecting layer is configured to block or
reflect a sufficient portion of the generated radiated heat-energy
so as to prevent the damage to the further layer that can be
damaged by exposure to said excessive amount of radiated
heat-energy.
2. The method of claim 1 wherein: the heat-energy
blocking/reflecting layer is configured to block or reflect
damaging photons in wavelength ranges below or above the visible
range.
3. The method of claim 2 wherein: the heat-energy
blocking/reflecting layer includes a metal that reflects IR
photons.
4. The method of claim 3 wherein: the heat-energy
blocking/reflecting layer includes or is attached to a material
that prevents or impedes substantial permeation of moisture and/or
oxygen therethrough.
5. The method of claim 1 wherein: the further layer that can be
damaged by exposure to said excessive amount of radiated
heat-energy is a light emitting and/or a selective light passage
controlling layer of the flexible display device.
6. The method of claim 5 wherein: the further layer that can be
damaged by exposure to said excessive amount of radiated
heat-energy includes organic light emitting elements.
7. The method of claim 6 wherein: the organic light emitting
elements can be damaged by exposure to moisture and/or oxygen; and
the heat-energy blocking/reflecting layer includes or is attached
to a material that prevents or impedes substantial permeation of
moisture and/or oxygen therethrough.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application of U.S. patent
application Ser. No. 14/293,947 filed on Jun. 2, 2014, which claims
priority to Korean Patent Application No. 10-2013-0094272, filed on
Aug. 8, 2013 in the Korean Intellectual Property Office (KIPO), and
all the benefits accruing therefrom under 35 U.S.C. .sctn.119, the
contents of the prior applications being herein incorporated by
reference.
BACKGROUND
[0002] (a) Field of Disclosure
[0003] The present disclosure relates to a flexible display and
manufacture of the same.
[0004] (b) Description of Related Technology
[0005] A flexible display that is light and strong and that uses a
flexible plastic substrate has been recently developed. Such a
flexible display can be folded or rolled in a roll-to-roll manner
so that portability of the flexible display can be maximized and
accordingly it can be applied to various fields.
[0006] The flexible display includes a display element formed on a
flexible substrate. A display element that can be used in the
flexible display can be an organic light emitting diode (OLED)
display element, a liquid crystal display element, an
electrophoretic display (EPD) element, and the like.
[0007] The flexible display uses a flexible material so that it can
maintain display performance even through it is bent like paper.
However, during mass production fabrication, the flexible display
is manufactured while being supported by and adhered to a rigid
substrate, for example, a carrier substrate.
[0008] When a process of layering several layers on the in-process
flexible display is finished, the adhesions of the flexible
substrate to its rigid support carrier is broken by, for example
irradiating from the bottom with laser beams to thereby separate
the flexible display from the carrier substrate. In this process, a
light emission layer or another photon absorbing layer of the
flexible display may be damaged due to receiving part of the
irradiation of the substrates separating laser beam.
[0009] It is to be understood that this background of the
technology section is intended to provide useful background for
understanding the here disclosed technology and as such, the
technology background section may include ideas, concepts or
recognitions that were not part of what was known or appreciated by
those skilled in the pertinent art prior to corresponding invention
dates of subject matter disclosed herein.
SUMMARY
[0010] A flexible display device is provided with a damage
preventing layer that can prevent damage to an overlying light
emission elements layer during mass production manufacture, where
the damage can be due to irradiation by laser beams used to
separate the in-process flexible display device from a supporting
carrier substrate during the manufacturing process.
[0011] A flexible display according to an exemplary embodiment
includes a substrate, a thin film transistors layer formed on the
substrate, and a light emitting elements layer formed on the thin
film transistor, where the substrate layer includes a first support
layer formed below the thin film transistors layer, a second
support layer disposed below the first support layer, and a
heat-energy blocking/reflecting layer provided between the first
support layer and the second support layer.
[0012] The flexible display may further include an insulating layer
formed at least between the first support layer and the reflective
layer or between the reflective layer and the second support
layer.
[0013] The first and/or second insulating layer may be made of a
silicon oxide (SiOx) or a silicon nitride (SiNx).
[0014] The heat-energy blocking/reflecting layer may be made of an
IR light reflecting metal.
[0015] The reflective layer may be predominantly composed of at
least one of aluminum (Al), chromium (Cr), and molybdenum (Mo).
[0016] The first support layer and the second support layer may be
made of a polyimide.
[0017] The light emitting elements layer may be one of an organic
light emitting elements layer, a liquid crystal display elements
layer, and an electrophoretic display elements layer.
[0018] The flexible display according to the exemplary embodiment
can prevent damage to the light emitting elements layer due to
irradiation of laser beams in a manufacturing process, and can
further, in one embodiment, effectively prevent or impede
permeation therethrough of moisture or oxygen into the light
emitting element after separation from the carrier substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a top plan view of a structure of a flexible
display according to an exemplary embodiment.
[0020] FIG. 2 is a circuit diagram of a pixel circuit of the
flexible display of FIG. 1.
[0021] FIG. 3 is a partially enlarged cross-sectional view of a
thin film transistor and a light emission element used in the
flexible display of FIG. 1.
[0022] FIG. 4 is partially enlarged cross-sectional view of a part
(i.e., a substrate) of the flexible display of FIG. 3.
[0023] FIG. 5 and FIG. 6 show a process of separation of the
flexible display according to the exemplary embodiment from the
carrier substrate.
DETAILED DESCRIPTION
[0024] In the following detailed description, only certain
exemplary embodiments in accordance with the present disclosure of
invention have been shown and described, simply by way of
illustration. As those skilled in the art would realize in light of
this disclosure, the described embodiments may be modified in
various different ways, all without departing from the spirit or
scope of the present teachings. The drawings and description are to
be regarded as illustrative in nature and not restrictive. Like
reference numerals designate like elements throughout the
specification.
[0025] The size and thickness of the components shown in the
drawings are optionally determined for better understanding and
ease of description, and the present disclosure is not limited to
the examples shown in the drawings.
[0026] In the drawings, the thickness of layers, films, panels,
regions, etc., are exaggerated for clarity. In addition, in the
drawings, for better understanding and ease of description, the
thickness of some layers and areas is exaggerated. It will be
understood that when an element such as a layer, film, region, or
substrate is referred to as being "on" another element, it can be
directly on the other element or intervening elements may also be
present.
[0027] In addition, unless explicitly described to the contrary,
the word "comprise" and variations such as "comprises" or
"comprising" will be understood to imply the inclusion of stated
elements but not the exclusion of any other elements. Further, it
will be understood that when an element such as a layer, film,
region, or substrate is referred to as being "on" another element,
it can be directly on the other element or intervening elements may
also be present.
[0028] Referring to FIG. 4 to FIG. 6, a flexible display according
to an exemplary embodiment has a structure that can prevent or
reduce likelihood of damage to an irradiation sensitive layer, for
example to an organic light emitting elements layer 400 due to the
use of laser beams for separation of in-process layers of the
flexible display form a supporting carrier substrate (e.g., 500 of
FIG. 5). The exemplary flexible display includes a flexible
substrate 200, a thin film transistor layer 300, and the organic
light emitting elements layer 400.
[0029] The substrate 200 includes a first support layer 210, a
second support layer 250, and a photons blocking and/or reflective
layer 230 (e.g., IR block/reflect layer 230). Details of the
substrate 200 will be described in detail later.
[0030] First, referring to FIG. 1 to FIG. 3, an overview of the
structure of the flexible display according to the exemplary
embodiment will be described.
[0031] Referring to the top plan view of FIG. 1, a flexible display
101 according to the exemplary embodiment includes a substrate main
body 111 divided into an image displaying area DA and a
non-displaying area NA. Here, the flexible display 101 will be
exemplarily illustrated as an organic light emission display formed
of organic light emitting elements populating the display area
(DA). However, the light emitting element of the flexible display
is not limited thereto, and a liquid crystal display element (e.g.,
a reflective kind), an electrophoretic display element, and the
like may be used instead.
[0032] A plurality of pixel areas PX are formed in the display area
DA of the substrate main body 111 to display an image, and one or
more driving circuits 910 and 920 are formed in the non-display
area NA. Here, the pixel area PX refers to an area where a pixel
which is a minimum unit for displaying a colored image is formed.
However, in the exemplary embodiment, it is not necessary to form
both the driving circuits 910 and 920 in the non-display area NA,
and the driving circuits 910 and 920 may be partially or entirely
omitted.
[0033] Referring to FIG. 2, the flexible display 101 according to
the exemplary embodiment includes a plurality of signal lines 21,
71, and 72 and pixels PX connected to the signal lines 21, 71, and
72. Each pixel or included-therein subpixel PX may be one of a red
pixel (R), a green pixel (G), a blue pixel (B) and/or a white (W)
pixel.
[0034] The signal lines include scan lines 21 transmitting gate
signals (or scan signals), data lines 71 transmitting data signals,
and driving voltage lines 72 transmitting driving voltages. The
scan signal lines 21 are substantially extended in a row direction
and almost parallel with each other, and the data lines 71 are
substantially extended in a column direction and almost parallel
with each other. The driving voltage lines 72 are substantially
extended in the column direction, but they may be formed in a net
shape rather than being extended in just one of the row or column
direction.
[0035] Each pixel PX includes a switching transistor Qs, a driving
transistor Qd, a storage capacitor Cst, and an organic light
emitting element LD.
[0036] The switching transistor Qs includes a control terminal N1,
an input terminal N2, and an output terminal N3. The control
terminal N1 is connected to the scan signal line 21, the input
terminal N2 is connected to the data line 71, and the output
terminal N3 is connected to the driving transistor Qd. The
switching transistor Qs transmits a data signal received from the
data line 71 in response to the scan signal received from the scan
signal line 21 to the driving transistor Qd.
[0037] The driving transistor Qd includes a control terminal N3, an
input terminal N4, and an output terminal N5, and the control
terminal N3 is connected to the switching transistor Qs, the input
terminal N4 is connected to the driving voltage line 72, and the
output terminal N5 is connected to the organic light emitting
element LD. The driving transistor Qd outputs an output current
I.sub.LD whose magnitude varies according to a voltage applied
between the control terminal N3 and the input terminal N4.
[0038] The capacitor Cst is connected between the control terminal
N3 and the input terminal N4 of the driving transistor Qd. The
capacitor Cst charges a data signal applied to the control terminal
N3 of the driving transistor Qd and maintains charging of the data
signal after the switching transistor Qs is turned off.
[0039] The organic light emitting element LD is, for example, an
organic light emitting diode (OLED), and includes an anode
connected to the output terminal N5 of the driving transistor Qd
and a cathode connected to a common voltage VSS. The organic light
emitting element LD emits light by varying an intensity according
to the output current ILD of the driving transistor Qd to display
an image. The organic light emitting element LD may include an
organic material which uniquely expresses any one or one or more of
primary colors such as three primary colors of red, green, and
blue, and the organic light emitting diode display displays a
desired image by a spatial and/or temporal sum of the output
colors.
[0040] The switching transistor Qs and the driving transistor Qd
are n-channel field effect transistors (FET), but at least one
thereof may be a p-channel field effect transistor. Further, a
connection relationship of the transistors Qs and Qd, the storage
capacitor Cst, and the organic light emitting element LD may be
changed.
[0041] Such a configuration of the pixel area PX is not limited to
the above, and can be variously modified within the scope that can
be easily modified by a person skilled in the art.
[0042] Next, referring to FIG. 3, the cross sectional structure of
the flexible display according to the exemplary embodiment will be
described according to a layering order. Here, the structure of the
driving transistor Qd and the organic light emitting element LD
will be mainly described in detail.
[0043] A substrate 123 is formed of a flexible substrate. The
substrate 123 has flexibility such that it can be used in the
flexible display, and this will be described in detail later.
[0044] A buffer layer 126 is formed on the substrate 123. The
buffer layer 126 prevents permeation of an impurity (e.g., moisture
and/or oxygen) and planarizes a surface.
[0045] In this case, the buffer layer 126 may be made of various
materials that can perform the above-stated functions. For example,
the buffer layer 126 may be formed of a single layer of one of a
silicon nitride (SiNx), a silicon oxide (SiO.sub.x), and a silicon
oxynitride (SiOxNy). However, the buffer layer 126 may not be
necessary, and may be omitted depending on the type and process
conditions of the substrate 123.
[0046] A driving semiconductor layer 137 is formed on the buffer
layer 126. The driving semiconductor layer 137 is formed of a
polysilicon layer. In addition, the driving semiconductor layer 137
includes a channel area 135 in which impurities are not doped and a
source area 134 and a drain area 136 in which impurities are doped
at respective sides of the channel area. In this case, implanted
ion materials may be used as the dopant impurities and these may be
a P-type impurity like boron B, and B.sub.2H.sub.6 is used in
general. Here, such an impurity is changed depending on the type of
the thin film transistor being formed.
[0047] A gate insulating layer 127 formed of a silicon nitride
(SiNx) or a silicon oxide (SiO.sub.x) is formed on the driving
semiconductor layer 137. Gate wires including a driving gate
electrode 133 are formed on the gate insulating layer 127. In
addition, the driving gate electrode 133 overlaps at least a part
of the driving semiconductor layer 137. Particularly, the driving
gate electrode 133 overlaps the channel area 135.
[0048] An interlayer insulating layer 128 that covers the driving
gate electrode 133 is formed on the gate insulating layer 127.
Through-holes that expose the source area 134 and the drain area
136 of the driving semiconductor layer 137 are respectively formed
in the gate insulating layer 127 and the interlayer insulating
layer 128. Like the gate insulating layer 127, the interlayer
insulating layer 128 may be made of a ceramic-based material such
as a silicon nitride (SiNx) or a silicon oxide (SiO.sub.x).
[0049] Data wires including a driving source electrode 131 and a
driving drain electrode 132 are formed on the interlayer insulating
layer 128. In addition, the driving source electrode 131 and the
driving drain electrode 132 are respectively connected with the
source area 134 and the drain area 136 of the driving semiconductor
layer 137 through the through-holes respectively formed in the
interlayer insulating layer 128 and the gate insulating layer
127.
[0050] As described, the driving semiconductor layer 137, the
driving gate electrode 133, the driving source electrode 131, and
the driving drain electrode 132 form a driving thin film transistor
130. However, the configuration of the driving thin film transistor
130 is not limited to the above-stated example, and may have
various known configurations that can be easily implemented by a
person skilled in the art.
[0051] In addition, a planarization layer 124 covering the data
wires is formed on the interlayer insulating layer 128. The
planarization layer 124 removes a topographical step feature and
planarizes a surface to improve light efficiency of an organic
light emitting element to be formed thereon. In addition, the
planarization layer 124 includes an electrode contact hole 122a
that partially exposes the drain electrode 132.
[0052] The planarization layer 124 may be made of at least one of a
polyacrylate resin, an epoxy resin, a phenolic resin, a polyamide
resin, a polyimide resin, an unsaturated polyester resin, a
polyphenylene ether resin, a polyphenylene sulfide resin, and
benzocyclobutene (BCB).
[0053] Here, the exemplary embodiment is not limited to the
above-stated structure, and one of the planarization layer 124 and
the interlayer insulating layer 128 may be omitted as
necessary.
[0054] In this case, a first electrode of the organic light
emitting element, that is, a pixel electrode 122b, is formed on the
planarization layer 124. That is, the flexible display includes a
plurality of pixel electrodes 122b provided in each of the
plurality of pixels. In this case, the plurality of pixel
electrodes 122b are separated from each other. Each pixel electrode
122b is connected with a respective drain electrode 132 through the
corresponding electrode contact hole 122a of the planarization
layer 124.
[0055] A pixel defining layer 125 having an opening that exposes
the pixel electrode 122b is formed on the planarization layer 124.
That is, the pixel defining layer 125 includes a plurality of
openings formed in each pixel. An organic emission layer 122c may
be formed in each opening formed within the pixel defining layer
125. Accordingly, a pixel area where an organic emission layer is
formed may be defined by the pixel defining layer 125.
[0056] In this case, the pixel electrode 122b is disposed
corresponding to the opening of the pixel defining layer 125, but
this is not restrictive. That is, the pixel electrode 122b may be
disposed below the pixel defining layer 125 such that a part of the
pixel electrode 112b may be overlapped with the pixel defining
layer 125.
[0057] The pixel defining layer 125 may be made of a resin such as
a polyacrylate resin, a polyimide resin, and the like, or a
silica-based inorganic material.
[0058] The organic emission layer 122c is formed on the pixel
electrode 122b. The organic emission layer 122c may further include
an emission layer (not shown) that substantially emits light in the
visible range, and organic layers (not shown) for efficient
transmission of carriers of holes or electrons to the emission
layer. The organic layers may include a hole injection layer and a
hole transport layer provided between the pixel electrode 122b and
the emission layer and an electron injection layer and an electron
transport layer provided between a common electrode 122d and the
emission layer.
[0059] In addition, a second electrode, that is, the common
electrode 122d, may be formed on the organic emission layer 122c.
As described, the organic light emitting element LD including the
pixel electrode 122b, the organic emission layer 122c, and the
common electrode 122d is formed.
[0060] In this case, the pixel electrode 122b and the common
electrode 122d may be respectively made of a transparent conductive
material or a semi-transmissive or reflective conductive material.
Depending of the type of material forming the pixel electrode 122b
and the common electrode 122d, the flexible display may be a front
emission type of display, a bottom emission type of display, or a
dual-side emissive type of display.
[0061] An overcoat 190 that protects the common electrode 122d by
covering the same may be formed as an organic layer on the common
electrode 122d.
[0062] In addition, a thin film encapsulation layer 121 is formed
on the overcoat 190. The thin film encapsulation layer 121 protects
the organic light emitting element LD and the driving circuit
formed in the substrate 123 by sealing them from the external
environment.
[0063] The thin film encapsulation layer 121 includes organic
encapsulation layers 121a and 121c and inorganic encapsulation
layers 121b and 121d, and the organic encapsulation layers 121a and
121c and the inorganic encapsulation layers 121b and 121d are
alternately layered. In FIG. 3, two organic encapsulation layers
121a and 121c and two inorganic encapsulation layers 121b and 121d
are alternately layered to form the thin film encapsulation layer
121, but this is not restrictive.
[0064] FIG. 4 is a schematic cross-sectional view of the flexible
display of FIG. 3, and the substrate 200, the thin film transistor
300, and the organic light emitting element 400 are sequentially
layered in the flexible display according to the exemplary
embodiment. Here, the substrate 200, the thin film transistor 300,
and the organic light emitting element 400 of FIG. 4 respectively
correspond to the substrate 123, the driving thin film transistor
130, and the organic light emitting element LD of FIG. 3.
[0065] Referring to FIG. 4, the substrate 200 includes the first
support layer 210, the second support layer 250, and the
heat-energy blocking/reflecting layer 230.
[0066] In this case, the first support layer 210 and the second
support layer 250 support the substrate 200, and form both side
surfaces of the substrate 200. That is, as described above, the
flexible substrate 200 is formed of dual support layers 210 and
250.
[0067] In this case, the first support layer 210 and the second
support layer 250 may be made of a polyimide having flexibility and
an excellent heat resisting characteristic among polymers instead
of a rigid material. However, the material of the first and second
support layers 210 and 250 is not limited thereto. Various
materials having a flexible characteristic can be used.
[0068] The first support layer 210 may be formed below the thin
film transistor 300, and the second support layer 250 may be
disposed opposite to the first support layer 210 so as to have the
heat-energy blocking/reflecting layer 230 interposed therebetween.
The first support layer 210 and the second support layer 250 may be
disposed at a distance from each other so as to interpose several
layers therebetween.
[0069] Referring to FIG. 4 to FIG. 6, the heat-energy
blocking/reflecting layer 230 is provided between the first support
layer 210 and the second support layer 250. The heat-energy
blocking/reflecting layer 230 blocks or reduces transmission of
radiative heat energy (e.g., radiative energy in the InfraRed (IR)
band of wavelengths) therethrough where the reflected and/or
otherwise blocked heat-energy arises due to irradiation from below
by laser beams applied to a lower portion of the carrier substrate
500 for the purpose of separating the carrier substrate 500 from
the second support layer 250.
[0070] As shown in FIG. 5, the flexible display is manufactured by
sequentially layering the substrate 200, the thin film transistor
layer 300, and the organic light emitting elements layer 400 on a
supporting carrier substrate 500 (e.g., a rigid carrier). Since the
flexible display has flexibility, it is supported by a rigid
substrate like that of the carrier substrate 500 during a
manufacturing process.
[0071] Referring to FIG. 5 and FIG. 6, when a process of layering
layers that form the flexible display on the carrier substrate 500
is finished, laser beams are irradiated to the lower portion of the
carrier substrate 500 to break down an adhesion mechanism that
binds the second support layer 250 with the carrier substrate 500
and to thereby separate the substrate 200 and the carrier substrate
500. In this case, radiative heat energy in the form of photons in
the InfraRed (IR) band of wavelengths is generated from the use of
the laser beams and this radiative heat energy is transmitted into
the flexible display. However, certain layers within the overlying
and in-process flexible display 200-300-400 may be damaged by the
upwardly transmitted radiative heat energy, for example the organic
light emitting elements layer 400 may be damaged and/or otherwise
undesirably influenced by the transmitted heat energy.
[0072] However, because the heat-energy blocking/reflecting layer
230 is provided between the first support layer 210 and the second
support layer 250 and is configured to block and/or reflect a
sufficient amount of the heat energy to prevent irreversible damage
to the organic light emitting elements layer 400 that might be
caused by the heat energy.
[0073] Meanwhile, when formed of appropriate materials, the
heat-energy blocking/reflecting layer 230 may additionally prevent
or impede permeation therethrough of moisture or oxygen into the
flexible display to thereby help improve the reliability and/or
usable lifetime of the flexible display.
[0074] According to the exemplary embodiment, the reflective layer
230 may be made of an IR-reflecting and 02 impermeable metal film.
The metallic heat-energy blocking/reflecting layer 230 can
therefore reflect back the upwardly radiated heat energy that
arises from the irradiation by the laser beam(s) in separating the
second support layer 250 from the carrier substrate 500.
[0075] In this case, the metal forming the heat-energy
blocking/reflecting layer 230 may be aluminum (Al), chromium (Cr),
molybdenum (Mo), alloys thereof and the like. However, the metal
forming the heat-energy blocking/reflecting layer 230 is not
limited thereto, and various other metals having high reflectivity
with respect to the spectrum of the radiated heat energy may be
applicable.
[0076] Referring to FIG. 4, a first insulating layer 220 is formed
between the first support layer 210 and the heat-energy
blocking/reflecting layer 230. In addition, a second insulating
layer 240 is formed between the heat-energy blocking/reflecting
layer 230 and the second support layer 250.
[0077] In this case, the first insulating layer 220 and the second
insulating layer 240 may be made of a silicon oxide (SiOx) or a
silicon nitride (SiNx). However, a material forming the first and
second support layers 210 and 250 is not limited thereto, and
various known materials that form an insulating layer used in a
display may be applicable. At least the first insulating layer 220
may be configured to impede thermal conduction therethrough.
[0078] At least one of the first insulating layer 220 and the
second insulating layer 240 may be further configured to prevent
permeation of undesired impurities into the organic light emitting
elements layer 400. In further detail, the first insulating layer
220 and the second insulating layer 240 can block permeation of
moisture or oxygen into the organic light emitting elements layer
400.
[0079] Thus, the flexible display according to the exemplary
embodiment can further effectively block permeation of moisture or
oxygen into the organic light emitting element 400 by at least one
of the first insulating layer 220 and the second insulating layer
240 while the heat-energy blocking/reflecting layer 230 blocks
and/or reflects a sufficient amount of the heat energy to prevent
irreversible damage to layers above itself.
[0080] Meanwhile, according to another exemplary embodiment, the
substrate 200 may include only one of the first insulating layer
220 and the second insulating layer 240. That is, the substrate 200
may include only the first insulating layer 220 disposed between
the first support layer 210 and the reflective layer 230 or only
the second insulating layer 240 disposed between the reflective
layer 230 and the second support layer 250.
[0081] The flexible display according to the exemplary embodiment
can prevent damage to the organic light emitting elements layer 400
due to irradiation of laser beams in a manufacturing process by
inclusion of the heat-energy blocking/reflecting layer, the first
insulating layer, and the second insulating layer in the substrate,
and can simultaneously prevent or impede permeation of moisture or
oxygen into the organic light emitting element.
[0082] It is to be noted that photon blocking patterns are
sometimes included in LCD displays for the purpose of blocking
passage of visible light photons from their backlighting systems
into the switching transistors that may be affected by such photons
in the visible light portion of the spectrum. However, the present
disclosure contemplates the blockage and/or reflecting of photons
in the InfraRed (IR) band of wavelengths and across substantially
all portions of the display area, including those that constitute
the light emitting and/or light valving aperture portions of the
display area (DA) for the purpose of preventing or limiting
irreversible damage to elements affected by such photons in the
InfraRed (IR) band. It is also within the contemplation of the
disclosure to block or reflect damaging photons in wavelength
ranges above the visible range (above about 700 nm, such as in the
low UV range).
[0083] While this disclosure of invention has been described in
connection with what is presently considered to be practical
exemplary embodiments, it is to be understood that the present
teachings are not limited to the disclosed embodiments, but, on the
contrary, they intended to cover various modifications and
equivalent arrangements included within the spirit and scope of the
present teachings.
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