U.S. patent application number 13/034600 was filed with the patent office on 2011-06-16 for fabricating methods of reflective liquid crystal display and top-emitting oled display.
This patent application is currently assigned to INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE. Invention is credited to Liang-Hsiang Chen, Jia Chong Ho, Jing-Yi Yan.
Application Number | 20110143468 13/034600 |
Document ID | / |
Family ID | 40931001 |
Filed Date | 2011-06-16 |
United States Patent
Application |
20110143468 |
Kind Code |
A1 |
Chen; Liang-Hsiang ; et
al. |
June 16, 2011 |
FABRICATING METHODS OF REFLECTIVE LIQUID CRYSTAL DISPLAY AND
TOP-EMITTING OLED DISPLAY
Abstract
Methods for forming a top-emitting organic light emitting
display and a reflective type liquid crystal display are provided.
The method for forming a top-emitting organic light emitting
display comprises: providing a handling substrate; providing a
composite layer on the handling substrate; forming an organic light
emitting unit on the composite layer; and forming a top electrode
on the organic light emitting unit.
Inventors: |
Chen; Liang-Hsiang;
(Taichung, TW) ; Yan; Jing-Yi; (Taoyuan City,
TW) ; Ho; Jia Chong; (Taipei Hsien, TW) |
Assignee: |
INDUSTRIAL TECHNOLOGY RESEARCH
INSTITUTE
HSINCHU
TW
|
Family ID: |
40931001 |
Appl. No.: |
13/034600 |
Filed: |
February 24, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12358098 |
Jan 22, 2009 |
7919917 |
|
|
13034600 |
|
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Current U.S.
Class: |
438/30 ;
257/E33.072; 257/E51.018; 438/34 |
Current CPC
Class: |
H01L 2251/5315 20130101;
H01L 2251/5338 20130101; G02F 1/133305 20130101; H01L 2227/326
20130101; H01L 51/56 20130101; G02F 1/133553 20130101; H01L
2227/323 20130101; H01L 51/52 20130101 |
Class at
Publication: |
438/30 ; 438/34;
257/E51.018; 257/E33.072 |
International
Class: |
H01L 33/60 20100101
H01L033/60; H01L 51/56 20060101 H01L051/56 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2008 |
TW |
TW97103678 |
Claims
1. A method for forming a top-emitting organic light emitting
display, comprising: providing a handling substrate; providing a
composite layer on the handling substrate; forming an organic light
emitting unit on the composite layer; and forming a top electrode
on the organic light emitting unit.
2. The method as claimed in claim 1, wherein the step of forming
the composite layer comprises: forming a first layer on the
handling substrate; forming a metal layer on the first layer
serving as a bottom electrode; and forming a second layer on the
metal layer.
3. The method as claimed in claim 2, wherein the first layer and
the second layer are formed by a coating process.
4. The method as claimed in claim 1, further comprising a step of
removing the handling substrate.
5. The method as claimed in claim 3, wherein the first layer and
the second layer comprise polycarbonate (PC), polyethersulfone
(PES), polyarylate (PAR), polyimide (PI), polyethylene
terephathalate (PET) or polyetherimide (PEI).
6. The method as claimed in claim 2, wherein the thickness of the
metal layer is from 10% to 50% the thickness of the first layer or
the second layer.
7. The method as claimed in claim 2, wherein the metal layer
comprises platinum (Pt), palladium (Pd), iridium (Ir), gold (Au),
tungsten (W), nickel (Ni), silver (Ag) or aluminum (Al).
8. The method as claimed in claim 7, wherein the metal layer is
formed by a hot embossing or electroless deposition process.
9. A method for forming a reflective type liquid crystal display,
comprising: providing a handling substrate; providing a composite
layer on the handling substrate; and forming a thin film transistor
array on the composite layer.
10. The method as claimed in claim 9, wherein the step of forming
the composite layer comprises: forming a first layer on the
handling substrate; forming a metal layer on the first layer; and
forming a second layer on the metal layer
11. The method as claimed in claim 10, further comprising: forming
a plurality of transparent pixel electrodes on the thin film
transistor array to connect to the thin film transistor array;
providing a transparent plastic substrate opposite to the first
layer; forming a common electrode on the transparent plastic
substrate and facing the first layer; and forming a liquid crystal
layer between the first layer and the transparent plastic
substrate.
12. The method as claimed in claim 10, wherein the first layer
serves as a flexible substrate of a display device.
13. The method as claimed in claim 10, wherein the first layer and
the second layer are formed by a coating process.
14. The method as claimed in claim 9, further comprising a step of
removing the handling substrate.
15. The method as claimed in claim 13, wherein the first layer or
the second layer comprise polycarbonate (PC), polyethersulfone
(PES), polyarylate (PAR), polyimide (PI), polyethylene
terephathalate (PET) or polyetherimide (PEI).
16. The method as claimed in claim 10, wherein the metal layer
comprises platinum (Pt), palladium (Pd), iridium (Ir), gold (Au),
tungsten (W), nickel (Ni), silver (Ag) or aluminum (Al)
17. The method as claimed in claim 16, wherein the metal layer is
formed by a hot embossing or electroless deposition process.
18. The method as claimed in claim 9, wherein the handling
substrate comprises glass, quartz, ceramic or silicon wafer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of pending U.S. patent
application Ser. No. 12/358,098, filed Jan. 22, 2009 and entitled
"Reflective liquid crystal display, top-emitting OLED display and
fabrication method thereof", which claims priority of Taiwan Patent
Application No. 97103678, filed on Jan. 31, 2008, the entirety of
which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a top-emitting OLED
display, and more particularly relates to a reflective type display
and fabrication method thereof. The present invention also relates
to a reflective type display, and more particularly relates to a
reflective type display and fabrication method thereof.
[0004] 2. Description of the Related Art
[0005] There are many advantages of a flexible display such as
having strong impact resistance, a lighter weight and flexibility.
In addition, flexible displays have the potential for application
in new emerging products such as electronic paper, electronic
tagging machines, credit cards, roll-up displays, and electronic
billboards, in addition to portable electronic devices. Therefore,
applications and technological advancements for flexible displays
have seen increased research and development recently. In general,
flexible substrate materials are classified into two categories:
plastic substrates of mainly organic materials; and metal foil of
mainly inorganic materials. Some advantageous for plastic
substrates such as polycarbonate (PC), polyethersulfone (PES),
polyarylate (PAR), polyimide (PI), polyethylene terephathalate
(PET) or polyetherimide (PEI), are that they have high transparency
and a relatively high external force distortion tolerance (e.g.,
may withstand multiple distortions).
[0006] However, one disadvantage of plastic substrates is that
water vapor is more easily absorbed by the plastic substrates.
Generally, the water vapor barrier rate of plastic substrates is
between 101 g/m.sup.2/day and 100 g/m.sup.2/day. On the other hand,
the water vapor barrier rate of TFT-LCDs and OLEDs are respectively
10.sup.-4g/m.sup.2/day and under 10.sup.-4g/m.sup.2/day. Thus, if
the plastic substrates are used, the operating lifespan of displays
or products using the plastic substrates will decrease.
[0007] As for metal foil substrates, some advantageous are that
water vapor is not easily absorbed by the metal foil substrate and
the metal foil substrate has flexibility. However, one disadvantage
of metal foil substrates is that metal foil substrates have a
relatively low external force distortion tolerance (e.g., unable to
withstand multiple distortions).
[0008] Therefore, a new method for fabricating a flexible display
is called for to alleviate the above constraints.
BRIEF SUMMARY OF THE INVENTION
[0009] A detailed description is given in the following embodiments
with reference to the accompanying drawings.
[0010] An embodiment of the invention discloses a method for
forming a top-emitting organic light emitting display, comprising:
providing a handling substrate; providing a composite layer on the
handling substrate; forming an organic light emitting unit on the
composite layer; and forming a top electrode on the organic light
emitting unit.
[0011] Another embodiment of the invention discloses a method for
forming a reflective type liquid crystal display, comprising:
providing a handling substrate; forming a first layer on the
handling substrate; forming a metal layer on the first layer;
forming a second layer on the metal layer; and forming a thin film
transistor array on the second layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention can be more fully understood by
reading the subsequent detailed description and examples with
references made to the accompanying drawings, wherein:
[0013] FIG. 1A to FIG. 1E are cross sections of a method for
forming a top-emitting organic light emitting display according to
an embodiment of the invention, illustrating fabrication steps
thereof.
[0014] FIG. 2A to FIG. 2B are cross sections of a method for
forming a reflective type liquid crystal display according to an
embodiment of the invention, illustrating fabrication steps
thereof.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The following description is of the best-contemplated mode
of carrying out the invention. This description is made for the
purpose of illustrating the general principles of the invention and
should not be taken in a limiting sense. The scope of the invention
is best determined by reference to the appended claims.
[0016] FIGS. 1A to 1E show cross sections of an exemplary
embodiment of a process for fabricating a top-emitting organic
light emitting display 200. Wherever possible, the same reference
numbers are used in the drawings and the descriptions to refer to
the same or like parts.
[0017] Referring to FIG. 1A, a handling substrate 110 is provided
and a selective cleaning process is performed for removing
pollutants of the handling substrate 110. The handling substrate
110 can be hard materials such as glass, quartz, ceramic or silicon
wafer. Then a composite layer is formed on the handling substrate
110, which may include forming a first layer covering the handling
substrate 110, forming a second layer covering the first layer, and
forming a metal layer between the first layer and the second layer.
In an embodiment of the invention, a first layer 120 is formed on
the handling substrate 110 as a lower substrate of a display. The
first layer 120 comprises several polymer materials such as
polycarbonate (PC), polyethersulfone (PES), polyarylate (PAR),
polyimide (PI), polyethylene terephathalate (PET) or polyetherimide
(PEI). In one embodiment of the invention, the first layer 120 can
be formed by coating processes such as a die coating or table
coating process and the like. After coating, the first layer 120 is
heated for solidification on the handling substrate 110.
[0018] As FIG. 1B shows, a metal layer 130 can be formed on the
first layer 120 by an electroless deposition process. In another
embodiment of the invention, the metal layer 130, as a metal foil
can be attached to the first layer 120 by a hot embossing process,
wherein the metal layer 130 serves as a lower electrode of the
display. Note that the metal layer 130 can also be a reflective
layer for reflecting any light impinging thereon. The metal layer
130 may include platinum (Pt), palladium (Pd), iridium (Ir), gold
(Au), tungsten (W), nickel (Ni), silver (Ag) or aluminum (Al).
[0019] Referring to FIG. 1C, a second layer 140 is formed on the
metal layer 130 as a passivation layer of the metal layer 130. The
second layer 140 and the first layer 120 can be formed of
substantially the same materials and processes. However, the second
layer 140 may be made of a polymer material which differs from a
polymer material of the first layer 120. Thus, the first layer 120,
the metal layer 130 and the second layer 140 constitute a composite
layer 145. Preferably, the thickness of the metal layer 130 is from
0.1 times to 0.5 times the thickness of the first layer 120 or the
second layer 140. Meanwhile, the thickness of the first layer 120
and of the second layer 140 can be the same or different.
[0020] Referring to FIG. 1D, an organic light emitting unit 260 is
formed on the composite layer 145. The organic light emitting unit
260 can comprise a hole injection layer 230, an organic light
emitting layer 240 and an electron injection layer 250. Following
is the manufacturing method for the organic light emitting unit
260. Firstly, the electron injection layer 230 and the organic
light emitting layer 240 are sequentially formed on the composite
layer 145. The electron injection layer 230 and the organic light
emitting layer 240 can be formed by a process such as a vacuum
evaporation process. The material of the electron injection layer
230 can be such as an m-MTDATA
(4,4',4''-tri{N-3-methylphenyl-N-phenyl-amino)-triphenylamine) and
the organic light emitting layer 240 can be formed by a process
such as a vacuum evaporation process. The material of the organic
light emitting layer 240 may be a doped organic material. Then, the
electron injection layer 250 is formed on the organic light
emitting layer 240 by a process such as a vacuum evaporation
process. The material of the electron injection layer 250 may be
formed of metal halide. Following, a top electrode 270 such as a
metal layer can be blanketly formed on the electron injection layer
250 by processes such as a vacuum evaporation or sputtering process
and the metal layer is patterned by processes such as a
photolithography and etching process. The metal layer may include
materials such as aluminum (Al), gold (Au) or platinum (Pt).
Finally, a transparent plastic substrate 280 is formed on the top
electrode 270 as an upper substrate of the display.
[0021] As FIG. 1E shows, the lower surface of the handling
substrate 110 which comprises the composite layer 145, the organic
light emitting unit 260, the top electrode 270 and the transparent
plastic substrate 280 is irradiated by a laser beam 60 to separate
the first layer 120 from the handling substrate 110. Since the
first layer 120 comprised of polymer materials is formed on the
handling substrate 110, a substantial non-contact interface may be
formed between the first layer 120 and the handling substrate 110.
Therefore, when the lower surface of the handling substrate 110 is
irradiated by the leaser beam 60, an internal stress is produced
between the first layer 120 and the handling substrate 110, wherein
the first layer 120 peels off from the handling substrate 110.
Thus, the composite layer 145, the organic light emitting unit 260,
the top electrode 270 and the transparent plastic substrate 280
constitute a flexible organic light emitting display 200.
[0022] It is noted that since the bottom electrode 130 of the
flexible organic light emitting display 200 is disposed between the
first layer 120 and the second layer 140, the bottom electrode 130
can be protected by both the first layer 120 and the second layer
140. For example, the second layer 140 can prevent possible damage
of the bottom electrode 130 during subsequent processes. In
addition, the bottom electrode 130 is comprised of metal materials
which can prevent water vapor from entering the organic light
emitting unit 260 for increasing the operating lifespan of the
flexible organic light emitting display 200. Additionally, since
the upper and lower substrates (i.e. the first layer 120 and the
transparent plastic substrate 280) of the flexible organic light
emitting display 200 are formed by polymers, possible damage caused
by external forces to the flexible organic light emitting display
200 comprised of a metal foil substrate and problems normally
associated with metal foil substrates such as having a relatively
low external force distortion tolerance (e.g., unable to withstand
multiple distortions) are prevented.
[0023] Additionally, the composite layer 145 can be applied to any
product which can use a flexible substrate with an installed metal
layer as a foundation on the flexible substrate. In the
aforementioned embodiments, although the descriptions only use the
flexible organic light emitting display, the invention is not
limited thereto. For instance, the composite layer 145 of the
embodiment of the invention can be applied to a flexible electronic
device such as a Radio Frequency Identification (RFID) and a
flexible display device such as an electrophoretic display (EPD) or
a field emission display (FED), and are also not limited
thereto.
[0024] Referring to FIG. 2, an embodiment of the invention for
fabricating a reflective type liquid crystal display is shown.
[0025] As FIG. 2A shows, a handling substrate 305 is provided and a
composite layer 330 is formed on the handling substrate 305. The
materials and methods for forming the handling substrate 305 and
the composite layer 330 are the same as the materials and methods
for forming the handling substrate 110 and the composite layer 145
in the embodiments of FIG. 1A to FIG. 1E. Similarly, the composite
layer 330 includes a first layer 300 covering the handling
substrate 305, a second layer 320 covering the first layer 300 and
a metal layer 310 between the first layer 300 and the second layer
320. Next, a thin film transistor (TFT) array 210 is formed on the
second layer 320. The TFT array 210 can be a bottom gate type or a
top gate type. Although the bottom gate type is used as
illustration, the invention is not intended to be limited
thereto.
[0026] Referring to FIG. 2A again, a plurality of transparent pixel
electrodes 410 are formed to connect to the TFT array 210. The
transparent pixel electrodes 410 may be an indium tin oxide (ITO)
electrode. Following, a transparent plastic substrate 440 is
provided as an upper substrate and the transparent plastic
substrate 440 is disposed on opposite sides of the handling
substrate 305. Next, a common electrode 430 such as an ITO
electrode is formed on the inside transparent plastic substrate
440. Then, a display layer 420 such as a liquid crystal layer is
filled between the handling substrate 305 and the transparent
plastic substrate 440. It is noted that the display material of the
display layer 420 can be changed appropriately. For example, the
display material such as a micro capsule having electrophoretic
characteristics also can be used as the display material of the
display layer 420.
[0027] As FIG. 2B shows, the lower surface of the handling
substrate 305 which comprise the composite layer 330 and the
elements of the reflective liquid crystal display is irradiated by
a laser beam 70 to separate the first layer 300 from the handling
substrate 305. Consequently, the composite layer 330, the TFT array
210, the pixel electrode 410, the display layer 420, the common
electrode 430 and the transparent plastic substrate 440 constitute
a flexible reflective liquid crystal display 500.
[0028] In this embodiment of the invention, since the metal layer
310 of the flexible reflective liquid crystal display 500 can
prevent water vapor from entering the display layer 420, the
operating lifespan of the flexible reflective liquid crystal
display 500 is increased when compared to a conventional flexible
reflective liquid crystal display without the metal layer 310.
[0029] While the invention has been described by way of example and
in terms of the preferred embodiments, it is to be understood that
the invention is not limited to the disclosed embodiments. To the
contrary, it is intended to cover various modifications and similar
arrangements (as would be apparent to those skilled in the art).
Therefore, the scope of the appended claims should be accorded the
broadest interpretation so as to encompass all such modifications
and similar arrangements.
* * * * *