U.S. patent application number 15/261373 was filed with the patent office on 2017-09-28 for organic light-emitting diode element and display device.
The applicant listed for this patent is BOE Technology Group Co., Ltd., HEFEI Xinsheng Optoelectronics Technology Co., Ltd. Invention is credited to Minghung Hsu, Yue Hu, Wenbin Jia, Rui Peng, Xinxin Wang, Zhijie Ye.
Application Number | 20170279077 15/261373 |
Document ID | / |
Family ID | 56048020 |
Filed Date | 2017-09-28 |
United States Patent
Application |
20170279077 |
Kind Code |
A1 |
Wang; Xinxin ; et
al. |
September 28, 2017 |
Organic Light-Emitting Diode Element and Display Device
Abstract
An organic light-emitting diode (OLED) element and a display
device are provided. The OLED element includes a base substrate and
an anode, an organic functional layer and a cathode sequentially
stacked on the base substrate. A thermal expansion layer is
disposed on at least one of a side of the anode away from the
organic functional layer or a side of the cathode away from the
organic functional layer and is a transparent thermal expansion
layer.
Inventors: |
Wang; Xinxin; (Beijing,
CN) ; Hsu; Minghung; (Beijing, CN) ; Jia;
Wenbin; (Beijing, CN) ; Peng; Rui; (Beijing,
CN) ; Ye; Zhijie; (Beijing, CN) ; Hu; Yue;
(Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BOE Technology Group Co., Ltd.
HEFEI Xinsheng Optoelectronics Technology Co., Ltd |
Beijing
Hefei City |
|
CN
CN |
|
|
Family ID: |
56048020 |
Appl. No.: |
15/261373 |
Filed: |
September 9, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02E 10/549 20130101;
H01L 51/5234 20130101; H01L 51/5253 20130101; H01L 51/5221
20130101; H01L 51/5265 20130101; H01L 2251/558 20130101; H01L
51/5271 20130101; H01L 51/5206 20130101; H01L 51/529 20130101; H01L
51/0096 20130101 |
International
Class: |
H01L 51/52 20060101
H01L051/52 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 25, 2016 |
CN |
201610179872.8 |
Claims
1. An organic light-emitting diode (OLED) element, comprising a
base substrate and an anode, an organic functional layer and a
cathode sequentially stacked on the base substrate, wherein a
thermal expansion layer is disposed on at least one of a side of
the anode away from the organic functional layer or a side of the
cathode away from the organic functional layer and is a transparent
thermal expansion layer.
2. The OLED element according to claim 1, wherein the thermal
expansion layer is disposed between the anode and base substrate
and in contact with the anode.
3. The OLED element according to claim 2, wherein light emitted by
the organic functional layer is emitted out of the OLED element
through the cathode; the OLED element further comprises a
reflective layer disposed between the anode and the base substrate;
and the thermal expansion layer is disposed between the reflective
layer and the anode.
4. The OLED element according to claim 3, wherein the OLED element
further comprises a transparent protective layer which is disposed
on the cathode.
5. The OLED element according to claim 2, wherein light emitted by
the organic functional layer is emitted out of the OLED element
through the anode; the OLED element further comprises a
transflective layer disposed between the anode and the base
substrate; and the thermal expansion layer is disposed between the
transflective layer and the anode.
6. The OLED element according to claim 1, wherein light emitted by
the organic functional layer is emitted out of the OLED element
through the cathode; and the thermal expansion layer is disposed on
a side of the cathode away from the organic functional layer and in
contact with the cathode.
7. The OLED element according to claim 6, wherein the OLED element
further comprises a reflective layer and a transition layer; the
reflective layer is disposed between the anode and the base
substrate; and the transition layer is disposed between the
reflective layer and the base substrate and in contact with the
reflective layer and the base substrate, respectively.
8. The OLED element according to claim 1, wherein light emitted by
the organic functional layer is emitted out of the OLED element
through the cathode; the thermal expansion layer is respectively
disposed on a side of the anode away from the organic functional
layer and a side of the cathode away from the organic functional
layer; the thermal expansion layer disposed on the side of the
anode away from the organic functional layer is in contact with the
anode; and the thermal expansion layer disposed on the side of the
cathode way from the organic functional layer is in contact with
the cathode.
9. The OLED element according to claim 1, wherein the OLED element
further comprises an electrothermal layer capable of being
connected with an external circuit; and the electrothermal layer is
disposed on a side of the thermal expansion layer away from the
organic functional layer, is in contact with the thermal expansion
layer, and is a transparent electrothermal layer.
10. The OLED element according to claim 1, wherein the thermal
expansion layer comprises at least one of the following: a thermal
expansion layer of a mixed thermal expansion material formed of
alkali silicate and polylol; a thermal expansion layer of a
zirconia-molybdenum gradient material formed of zirconia and
molybdenum; or a thermal expansion layer of a negative thermal
expansion material thermal.
11. A display device, comprising the OLED element according to
claim 1.
12. The display device according to claim 11, wherein the thermal
expansion layer is disposed between the anode and the base
substrate and in contact with the anode.
13. The display device according to claim 12, wherein light emitted
by the organic functional layer is emitted out of the OLED element
through the cathode; the OLED element further comprises a
reflective layer disposed between the anode and the base substrate;
and the thermal expansion layer is disposed between the reflective
layer and the anode.
14. The display device according to claim 13, wherein the OLED
element further comprises a transparent protective layer which is
disposed on the cathode.
15. The display device according to claim 12, wherein light emitted
by the organic functional layer is emitted out of the OLED element
through the anode; the OLED element further comprises a
transflective layer disposed between the anode and the base
substrate; and the thermal expansion layer is disposed between the
transflective layer and the anode.
16. The display device according to claim 11, wherein light emitted
by the organic functional layer is emitted out of the OLED element
through the cathode; and the thermal expansion layer is disposed on
a side of the cathode away from the organic functional layer and in
contact with the cathode.
17. The display device according to claim 16, wherein the OLED
element further comprises a reflective layer and a transition
layer; the reflective layer is disposed between the anode and the
base substrate; and the transition layer is disposed between the
reflective layer and the base substrate and is in contact with the
reflective layer and the base substrate, respectively.
18. The display device according to claim 11, wherein light emitted
by the organic functional layer is emitted out of the OLED element
through the cathode; the thermal expansion layer is respectively
disposed on a side of the anode away from the organic functional
layer and a side of the cathode away from the organic functional
layer; the thermal expansion layer disposed on the side of the
anode away from the organic functional layer is in contact with the
anode; and the thermal expansion layer disposed on the side of the
cathode way from the organic functional layer is in contact with
the cathode.
19. The display device according to claim 11, wherein the OLED
element further comprises an electrothermal layer capable of being
connected with an external circuit; and the electrothermal layer is
disposed on a side of the thermal expansion layer away from the
organic functional layer, is in contact with the thermal expansion
layer, and is a transparent electrothermal layer.
20. The display device according to claim 11, wherein the thermal
expansion layer comprises at least one of the following: a thermal
expansion layer of a mixed thermal expansion material formed of
alkali silicate and polylol; a thermal expansion layer of a
zirconia-molybdenum gradient material formed of zirconia and
molybdenum; or a thermal expansion layer of a negative thermal
expansion material thermal.
Description
[0001] This application claims priority to and the benefit of
Chinese Patent Application No. 201610179872.8 filed on Mar. 25,
2016, which application is incorporated herein in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to an organic light-emitting
diode (OLED) element and a display device.
BACKGROUND
[0003] Organic electroluminescent element, also referred to as OLED
element, receives much concern due to the advantages of
self-illumination, rich color, rapid response speed, wide viewing
angle, light weight, low thickness, low power consumption,
capability of achieving flexible display, etc. Moreover, display
devices manufactured by the OLED elements are considered as display
devices with significant application prospect.
[0004] The basic structure of the OLED element is a sandwich
structure formed by an anode, a cathode and an organic functional
layer disposed between the anode and the cathode, wherein the
organic functional layer generally includes a hole transport layer
(HTL), an emission layer (EML), an electron transport layer (ETL),
etc. When voltage is applied to the OLED element, holes outputted
from the anode and electrons outputted from the cathode are
combined in the organic functional layer, so that the organic
functional layer can emit light and the light emitted by the
organic functional layer is emitted out of the OLED element through
the anode or the cathode.
[0005] However, after the conventional OLED element is
manufactured, the thickness of layers of the OLED element is
unchanged, so the optical cavity length of the OLED element is
nonadjustable and the wavelength of light emitted by the OLED
element is unchanged, namely the light color of the OLED element is
also nonadjustable, and hence the display effect of the display
device can be poor.
SUMMARY
[0006] One aspect of the disclosure provides an organic
light-emitting diode (OLED) element, comprising a base substrate
and an anode, an organic functional layer and a cathode
sequentially stacked on the base substrate, wherein a thermal
expansion layer is disposed on at least one of a side of the anode
away from the organic functional layer or a side of the cathode
away from the organic functional layer and is a transparent thermal
expansion layer.
[0007] Based on the technical solution of OLED element as mentioned
above, a second aspect of the disclosure provides a display device
comprising the OLED element as mentioned above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] In order to clearly illustrate the technical solution of the
embodiments of the invention, the drawings of the embodiments will
be briefly described in the following; it is obvious that the
described drawings are only related to some embodiments of the
invention and thus are not limitative of the invention.
[0009] FIG. 1 is a schematic structural view 1 of an OLED element
provided by the embodiment of the present invention;
[0010] FIG. 2 is a schematic structural view 2 of the OLED element
provided by the embodiment of the present invention;
[0011] FIG. 3 is a schematic structural view 3 of the OLED element
provided by the embodiment of the present invention; and
[0012] FIG. 4 is a schematic structural view 4 of the OLED element
provided by the embodiment of the present invention.
DETAILED DESCRIPTION
[0013] In order to make objects, technical details and advantages
of the embodiments of the invention apparent, the technical
solutions of the embodiment will be described in a clearly and
fully understandable way in connection with the drawings related to
the embodiments of the invention. It is obvious that the described
embodiments are just a part but not all of the embodiments of the
invention. Based on the described embodiments herein, those skilled
in the art can obtain other embodiment(s), without any inventive
work, which should be within the scope of the invention.
[0014] As illustrated in FIGS. 1 to 4, the OLED element provided by
the embodiment of the present invention comprises a base substrate
1 and an anode 2, an organic functional layer 3 and a cathode 4
sequentially stacked on the base substrate 1. A thermal expansion
layer 5 is disposed on a side of the anode 2 away from the organic
functional layer 3, and/or, a thermal expansion layer 5 is disposed
on a side of the cathode 4 away from the organic functional layer
3. The thermal expansion layer 5 is a transparent thermal expansion
layer.
[0015] It should be noted that the OLED element may generally be
divided into top-emission OLED element and bottom-emission OLED
element according to different emission directions of light from
the OLED element. In the top-emission OLED element, light emitted
by the organic functional layer 3 is emitted from the direction
away from the base substrate 1, namely the light emitted by the
organic functional layer 3 is emitted from the top of the OLED
element. That is to say, the light emitted by the organic
functional layer 3 is emitted from the top of FIG. 1, 2 or 3. In
the bottom-emission OLED element, light emitted by the organic
functional layer 3 is emitted from the base substrate 1, namely the
light emitted by the organic functional layer 3 is emitted from the
bottom of the OLED element. That is to say, the light emitted by
the organic functional layer 3 is emitted from the bottom of FIG.
4. The thermal expansion layer 5 may be specifically set according
to different types of OLED elements.
[0016] In some examples, the OLED element provided by the
embodiment of the present invention comprises a base substrate 1
and an anode 2, an organic functional layer 3 and a cathode 4
sequentially stacked on the base substrate 1. The anode 2 may adopt
an indium tin oxide (ITO) anode; the cathode 4 may adopt a metal
cathode; and the organic functional layer 3 generally includes a
hole transport layer (HTL), an electro-luminescence layer (EML) and
an electron transport layer (ETL) which are sequentially stacked.
The HTL makes contact with the anode 2, and the ETL makes contact
with the cathode 4. The position of a transparent thermal expansion
layer 5 may be specifically set according to different types of
OLED elements. For instance, in the top-emission OLED element, the
thermal expansion layer 5 may be disposed beneath the anode 2 in
FIG. 1, or the thermal expansion layer 5 may be disposed on the
cathode 4 in FIG. 2, or the thermal expansion layer 5 may be
respectively disposed beneath the anode 2 and on the cathode 4 in
FIG. 3. In the bottom-emission OLED element, the thermal expansion
layer 5 may be disposed beneath the anode 2 in FIG. 4.
[0017] When the OLED element works, the thermal expansion layer 5
absorbs heat produced when the organic functional layer 3 emits
light, and/or, the thermal expansion layer 5 absorbs heat applied
to the thermal expansion layer 5 by external world, so that the
temperature of the thermal expansion layer 5 is changed, and hence
the thickness of the thermal expansion layer 5 is changed. When
light emitted by the organic functional layer 3 is incident into
the thermal expansion layer 5 and runs through the thermal
expansion layer 5, as the thickness of the thermal expansion layer
5 is changed, the time of the light emitted by the organic
functional layer 3 running through the thermal expansion layer 5
can be adjusted, and the wavelength of the light emitted by the
organic functional layer 5 after running through the thermal
expansion layer 5 can be adjusted, and hence the wavelength of
light emitted by the OLED element can be adjusted. Thus, the light
color of the OLED element can be adjusted, so that the light color
of OLED elements in a display device is matched with each other,
and hence the display effect of the OLED element can be
improved.
[0018] In the embodiment, the thermal expansion layer 5 may be
specifically set according to different types of OLED elements.
Exemplary description will be given below to the setting means of
the thermal expansion layer 5 in different types of OLED
elements.
[0019] In the top-emission OLED element, the setting modes of the
thermal expansion layer 5 may include but not limited to the
following three means.
[0020] First mode: as illustrated in FIG. 1, the thermal expansion
layer 5 is disposed between the anode 2 and the base substrate 1
and makes contact with the anode 2. For example, the OLED element
comprises a base substrate 1, an anode 2, an organic functional
layer 3, a cathode 4 and a thermal expansion layer 5, wherein the
thermal expansion layer 5, the anode 2, the organic functional
layer 3 and the cathode 4 are sequentially stacked on the base
substrate 1; the thermal expansion layer 5 makes contact with the
anode 2; and the cathode 4 is a semitransparent metal cathode. When
the OLED element works, a part of light emitted by the organic
functional layer 3 is directly emitted out of the OLED element from
the top in FIG. 1 through the cathode 4, and the other part is
incident into the thermal expansion layer 5 through the anode 2. At
this point, heat produced by the organic functional layer 3 is
conducted to the thermal expansion layer 5 through the anode 2,
and/or, the thermal expansion layer 5 absorbs heat applied to the
thermal expansion layer 5 by external world, so that the
temperature of the thermal expansion layer 5 is changed, and hence
the thickness of the thermal expansion layer 5 is also changed.
Thus, the time of the light incident into the thermal expansion
layer 5 running through the thermal expansion layer 5 is also
changed, and hence the wavelength of the light emitted from the
bottom of the thermal expansion layer 5 in FIG. 1 is adjusted. The
light emitted from the bottom of the thermal expansion layer 5 in
FIG. 1 is reflected on the base substrate 1 or reflecting materials
on the base substrate 1 and runs through the thermal expansion
layer 5 again, namely the wavelength of this part of light is
adjusted again. The light running through the thermal expansion
layer 5 sequentially runs through the organic functional layer 3
and the cathode 4 and is emitted out of the OLED element.
[0021] The thermal expansion layer 5 makes contact with the anode
2. This case can accelerate the transmission speed of heat produced
by the organic functional layer 3, so as to rapidly adjust the
temperature of the thermal expansion layer 5 and rapidly adjust the
thickness of the thermal expansion layer 5, accelerate the response
speed of adjusting the wavelength of the light emitted by the OLED
element, and hence reduce the response time of adjusting the
wavelength of the light emitted by the OLED element.
[0022] In the first mode, in order to allow light running through
the anode 2 to be emitted out of the OLED element from the top of
the OLED element and improve the utilization rate of the light
emitted by the organic functional layer 3, the base substrate 1 may
be set to be a nontransparent base substrate; a part of light
emitted by the organic functional layer 3 sequentially runs through
the anode 2 and the thermal expansion layer 5, is reflected on the
base substrate 1, subsequently sequentially runs through the
thermal expansion layer 5, the anode 2, the organic functional
layer 3 and the cathode 4, and is emitted out of the OLED element;
or a layer of reflecting material is disposed between the base
substrate 1 and the thermal expansion layer 5, and a part of light
emitted by the organic functional layer 3 sequentially runs through
the anode 2 and the thermal expansion layer 5, is reflected on the
reflecting material, subsequently sequentially runs through the
thermal expansion layer 5, the anode 2, the organic functional
layer 3 and the cathode 4, and is emitted out of the OLED element.
Thus, the light running through the anode 2 can be emitted out of
the OLED element from the top of the OLED element, so that the
utilization rate of the light emitted by the organic functional
layer 3 can be improved.
[0023] In the embodiment of the present invention, as illustrated
in FIG. 1, the light running through the anode 2 is emitted out of
the OLED element from the top of the OLED element by forming a
layer of reflecting material on the base substrate 1. For instance,
as illustrated in FIG. 1, the OLED element further comprises a
reflective layer 6 disposed between the anode 2 and the base
substrate 1; and the thermal expansion layer 5 is disposed between
the reflective layer 6 and the anode 2. That is to say, the OLED
element comprises: a base substrate 1 and a reflective layer 6, a
thermal expansion layer 5, an anode 2, an organic functional layer
3 and a cathode 4 which are sequentially stacked on the base
substrate 1. The thermal expansion layer 5 makes contact with the
anode 2. Due to the setting of the reflective layer 6, the light
sequentially running through the anode 2 and the thermal expansion
layer 5 is reflected and subsequently sequentially runs through the
thermal expansion layer 5, the anode 2, the organic functional
layer 3 and the cathode 4. Thus, the utilization rate of the light
emitted by the organic functional layer 3 can be improved.
[0024] In the top-emission OLED element, the cathode 4 is generally
a semitransparent metal cathode and has low thickness. Thus, in
order to prevent the cathode 4 from being damaged, as illustrated
in FIG. 1, the OLED element further comprises a transparent
protective layer 8 which is disposed on the cathode 4. For
instance, the OLED element comprises: a base substrate 1 and a
reflective layer 6, a thermal expansion layer 5, an anode 2, an
organic functional layer 3, a cathode 4 and a transparent
protective layer 8 which are sequentially stacked on the base
substrate 1, wherein the thermal expansion layer 5 makes contact
with the anode 2, and the transparent protective layer 8 is
disposed on the cathode 4 and makes contact with the cathode 4. Due
to the setting of the transparent protective layer 8, the cathode 4
may be isolated from the external world, so that the transparent
protective layer can have the function of protecting the cathode 4
and prevent the cathode 4 from being damaged.
[0025] In addition, when the light emitted by the organic
functional layer 3 is emitted out of the OLED element through the
cathode 4, as the refractive index of the cathode 4 is greater than
that of the air, when the light is incident into the air from the
cathode 4, the light tends to be totally reflected on an interface
of the cathode 4 and the air. Therefore, in order to reduce the
degree of total reflection of the light on the interface of the
cathode 4 and the air, the transparent protective layer 8 of which
the refractive index is between the refractive index of the cathode
4 and the refractive index of the air may be selected, so that the
degree of total reflection of the light on the interface of the
cathode 4 and the air can be reduced, and hence the light
extraction can be improved.
[0026] Second mode: as illustrated in FIG. 2, the thermal expansion
layer 5 is disposed on a side of the cathode 4 away from the
organic functional layer 3 and makes contact with the cathode 4.
For example, the OLED element comprises a base substrate 1, an
anode 2, an organic functional layer 3, a cathode 4 and a thermal
expansion layer 5, wherein the anode 2, the organic functional
layer 3, the cathode 4 and the thermal expansion layer 5 are
sequentially stacked on the base substrate 1; the thermal expansion
layer 5 makes contact with the cathode 4; and the cathode 4 is a
semitransparent metal cathode. When the OLED element works, a part
of light emitted by the organic functional layer 3 is incident into
the thermal expansion layer 5 through the cathode 4 and emitted out
of the OLED element through the thermal expansion layer 5, and the
other part of light runs through the anode 2, is reflected on the
base substrate 1 or reflecting materials on the base substrate 1,
subsequently sequentially runs through the anode 2, the organic
functional layer 3 and the cathode 4, is incident into the thermal
expansion layer 5, and is emitted out of the OLED element through
the thermal expansion layer 5. When the OLED element works, heat
produced by the organic functional layer 3 is conducted to the
thermal expansion layer 5 through the cathode 4, and/or, the
thermal expansion layer 5 absorbs heat applied to the thermal
expansion layer 5 by external world, so that the temperature of the
thermal expansion layer 5 is changed and the thickness of the
thermal expansion layer 5 is also changed, and hence the time of
the light emitted by the organic functional layer 3 running through
the thermal expansion layer 5 is changed. Thus, after the light
emitted by the organic functional layer 3 runs through the thermal
expansion layer 5, the wavelength is adjusted, namely the
wavelength of the light emitted by the OLED element is adjusted,
and hence the light color of the OLED element is adjusted.
[0027] The thermal expansion layer 5 makes contact with the cathode
4. The case can accelerate the transmission speed of the heat
produced by the organic functional layer 3, so as to rapidly adjust
the temperature of the thermal expansion layer 5 and rapidly adjust
the thickness of the thermal expansion layer 5, accelerate the
response speed of adjusting the wavelength of the light emitted by
the OLED element, and hence reduce the response time of adjusting
the wavelength of the light emitted by the OLED element. In
addition, the thermal expansion layer 5 is disposed on the cathode
4 and may isolate the cathode 4 from the external world and prevent
the cathode 4 from being damaged.
[0028] As illustrated in FIG. 2, the OLED element further comprises
a reflective layer 6 and a transition layer 7. The reflective layer
6 is disposed between the anode 2 and the base substrate 1. The
transition layer 7 is disposed between the reflective layer 6 and
the base substrate 1 and respectively makes contact with the
reflective layer 6 and the base substrate 1. For instance, the OLED
element comprises: a base substrate 1 and a transition layer 7, a
reflective layer 6, an anode 2, an organic functional layer 3, a
cathode 4 and a thermal expansion layer 5 which are sequentially
stacked on the base substrate 1, wherein the transition layer 7
respectively makes contact with the base substrate 1 and the
reflective layer 6, and the thermal expansion layer 5 makes contact
with the cathode 4. Due to the setting of the reflective layer 6,
the light emitted by the organic functional layer 3 is reflected to
the top of the OLED element, so that the utilization rate of the
light emitted by the organic functional layer 3 can be improved.
Due to the setting of the transition layer 7, a gap formed between
the reflective layer 6 and the base substrate 1 due to small
bonding force between the reflective layer 6 and the base substrate
1 can be avoided, namely the transition layer 7 has the function of
transition. In addition, due to the setting of the transition layer
7, light running through the reflective layer 6 may also be
reflected to the top of the OLED element, so that the utilization
rate of the light emitted by the organic functional layer 3 can be
further improved. The reflective layer 6 may be a metal reflective
layer, e.g., an aluminum reflective layer or an aluminum alloy
reflective layer, and the transition layer 7 may also be a metal
transition layer.
[0029] Third mode: as illustrated in FIG. 3, the thermal expansion
layer 5 is respectively disposed on a side of the anode 2 away from
the organic functional layer 3 and a side of the cathode 4 away
from the organic functional layer 3; the thermal expansion layer 5
disposed on the side of the anode 2 away from the organic
functional layer 3 makes contact with the anode 2; and the thermal
expansion layer 5 disposed on the side of the cathode 4 away from
the organic functional layer 3 makes contact with the cathode 4.
For instance, the OLED element comprises: a base substrate 1 and a
reflective layer 6, a thermal expansion layer 5, an anode 2, an
organic functional layer 3, a cathode 4 and a thermal expansion
layer 5 which are sequentially stacked on the base substrate 1.
When the OLED element works, the thermal expansion layer 5 beneath
the anode 2 and the thermal expansion layer 5 on the cathode 4
respectively absorb heat produced by the organic functional layer
3, and/or, the thermal expansion layers 5 absorb heat applied to
the thermal expansion layers 5 by external world, so that the
temperature of the two thermal expansion layers 5 is changed, and
hence the thickness of the two thermal expansion layers 5 is
correspondingly changed according to the variation of respective
temperature. Thus, the wavelength of light running through the
thermal expansion layers 5 respectively is adjusted, so that the
wavelength of the light emitted by the OLED element is adjusted,
and hence the light color of the OLED element is adjusted, and
consequently the display effect of the display device can be
improved.
[0030] In the bottom-emission OLED element, the setting mode of the
thermal expansion layer 5 includes but not limited to the following
mode.
[0031] Fourth mode: as illustrated in FIG. 4, the thermal expansion
layer 5 is disposed between the anode 2 and the base substrate 1
and makes contact with the anode 2. That is to say, a thermal
expansion layer 5, an anode 2, an organic functional layer 3 and a
cathode 4 are sequentially stacked on a base substrate 1; the base
substrate 1 is a transparent base substrate, e.g., a glass base
substrate; the anode 2 may be an ITO anode; and the cathode 4 may
be a metal cathode. When the OLED element works, a part of light
emitted by the organic functional layer 3 is incident into the
thermal expansion layer 5 through the anode 2, runs through the
thermal expansion layer 5, and is emitted out of the OLED element
from the base substrate 1, and the other part of light is reflected
on the cathode 4, is incident into the thermal expansion layer 5
through the anode 2, runs through the thermal expansion layer 5,
and is emitted out of the OLED element from the base substrate 1.
When the OLED operates, heat produced by the organic functional
layer 3 is conducted to the thermal expansion layer 5 through the
anode 2, and/or, the thermal expansion layer 5 absorbs heat applied
to the thermal expansion layer 5 by external world, so that the
temperature of the thermal expansion layer 5 is changed, and hence
the thickness of the thermal expansion layer 5 is also changed.
Thus, the time of the light emitted by the organic functional layer
3 running through the thermal expansion layer 5 is adjusted, so
that the wavelength of the light after running through the thermal
expansion layer 5 is adjusted, and hence the wavelength of the
light emitted by the OLED element is adjusted, and consequently the
light color of the OLED element is adjusted.
[0032] As illustrated in FIG. 4, the OLED element further comprises
a transflective layer 9 disposed between the anode 2 and the base
substrate 1, and the thermal expansion layer 5 is disposed between
the transflective layer 9 and the anode 2. For instance, the OLED
element comprises a base substrate 1, a transflective layer 9, a
thermal expansion layer 5, an anode 2, an organic functional layer
3 and a cathode 4, wherein the transflective layer 9, the thermal
expansion layer 5, the anode 2, the organic functional layer 3 and
the cathode 4 are sequentially stacked on the base substrate 1.
When the OLED element works, a part of light running through the
thermal expansion layer 5 runs through the transflective layer 9
and is emitted out of the OLED element from the base substrate 1,
and the other part of light is reflected on the transflective layer
9, sequentially runs through the thermal expansion layer 5, the
anode 2 and the organic functional layer 3, is reflected on the
cathode 4, subsequently sequentially runs through the organic
functional layer 3, the anode 2 and the thermal expansion layer 5,
and is incident into the transflective layer 9. The above
transmission process is repeated, so that the wavelength of the
light emitted by the organic functional layer 3 is adjusted for a
plurality of times, and hence the light color of the OLED element
is adjusted. Thus, the wavelength and the light color of the light
emitted by OLED elements in a display device are matched with each
other, and hence the display effect of the display device can be
improved.
[0033] In order to further adjust the thickness of the thermal
expansion layer 5, as illustrated in FIGS. 1 to 4, the OLED element
further comprises an electrothermal layer 10 connected with an
external circuit. The electrothermal layer 10 is disposed on a side
of the thermal expansion layer 5 away from the organic functional
layer 3, makes contact with the thermal expansion layer 5, and is a
transparent electrothermal layer.
[0034] For example, when the OLED element is a top-emission OLED
element, as illustrated in FIG. 1, the thermal expansion layer 5 is
disposed between the base substrate 1 and the anode 2 and makes
contact with the thermal expansion layer 5, and the electrothermal
layer 10 may be disposed between the thermal expansion layer 5 and
the base substrate 1 and makes contact with the thermal expansion
layer 5. As illustrated in FIG. 2, the thermal expansion layer 5 is
disposed on a side of the cathode 4 away from the organic
functional layer 3 and makes contact with the cathode 4, and the
electrothermal layer 10 is disposed on a side of the thermal
expansion layer 5 away from the organic functional layer 3 and
makes contact with the thermal expansion layer 5. As illustrated in
FIG. 3, the thermal expansion layer 5 is respectively disposed
beneath the anode 2 and on the cathode 4; the thermal expansion
layer 5 on the upper part in FIG. 3 makes contact with the cathode
4, and the thermal expansion layer 5 on the lower part in FIG. 3
makes contact with the anode 2; and the electrothermal layer 10 is
respectively disposed on the thermal expansion layer 5 on the upper
part in FIG. 3 and beneath the thermal expansion layer 5 on the
lower part in FIG. 3 and respectively makes contact with
corresponding thermal expansion layer 5.
[0035] When the OLED element is a bottom-emission OLED element, as
illustrated in FIG. 4, the thermal expansion layer 5 is disposed
between the base substrate 1 and the anode 2 and makes contact with
the anode 2, and the electrothermal layer 10 may be disposed
between the thermal expansion layer 5 and the base substrate 1 and
makes contact with the thermal expansion layer 5.
[0036] When the OLED element works, power is supplied to the
electrothermal layer 10 through the external circuit, and heat is
gradually emitted by the electrothermal layer 10 and transmitted to
the thermal expansion layer 5, so that the temperature of the
thermal expansion layer 5 is gradually raised, and hence the
thickness of the thermal expansion layer 5 is changed. Thus, the
wavelength of the light emitted by the organic functional layer 3
running through the thermal expansion layer 5 is adjusted, so that
the wavelength of the light emitted by the OLED element is
adjusted, and hence the light color of the OLED element is
adjusted. Therefore, the light color of OLED elements in a display
device is matched with each other, and hence the display effect of
the OLED element is further improved.
[0037] When the thickness of the thermal expansion layer 10 is not
required to be continuous increased or the thickness of the thermal
expansion layer 10 must be reduced, the connection between the
external circuit and the electrothermal layer 10 may be cut off;
the external circuit stops supplying power to the electrothermal
layer 10; the electrothermal layer 10 may be taken as a heat
dissipation layer; and the heat of the thermal expansion layer 5 is
conducted to other layer structures of the OLED element or the
outside of the OLED element, so that the temperature of the thermal
expansion layer 5 is reduced, and hence the thickness of the
thermal expansion layer 5 is reduced. As the thickness of the
thermal expansion layer 5 can be adjusted, the light color of the
OLED element can be adjusted.
[0038] In the embodiment, the thermal expansion layer 5 may be made
from a plurality of materials. For instance, the thermal expansion
layer 5 may be a mixed thermal expansion material thermal expansion
layer formed of alkali silicate and polylol, e.g., mixed thermal
expansion materials formed of sodium silicate and glycerol; or the
thermal expansion layer 5 may be a zirconia-molybdenum gradient
material thermal expansion layer formed of zirconia and molybdenum;
or the thermal expansion layer 5 may be a negative thermal
expansion (NTE) material thermal expansion layer, e.g., Mn.sub.3ZnN
and ZrW.sub.2O.sub.8.
[0039] For instance, in the OLED element provided by the above
embodiments, the thickness of the thermal expansion layer 5 can be
changed due to the thermal expansion of the thermal expansion
layer, so that the optical cavity length of the OLED element can be
varied. Due to the variation of the optical cavity length, the
wavelength of the light emitted by the OLED element can be adjusted
to a certain degree.
[0040] The embodiment of the present invention further provides a
display device, which comprises the OLED elements provided by the
above embodiment.
[0041] The advantages of the display device are the same with those
of the OLED element. No further description will be given here.
[0042] In the embodiment, the thermal expansion layer may be formed
by a plurality of methods, e.g., vapor deposition method,
spin-coating method, coating method or plasma enhanced chemical
vapor deposition (PECVD) method.
[0043] In the description of the embodiment, the specific features,
structures, materials or characteristics may be combined with each
other by appropriate means in any one or more embodiments.
[0044] The foregoing is only the preferred embodiments of the
present invention and not intended to limit the scope of protection
of the present invention. The scope of protection of the present
invention should be defined by the appended claims.
[0045] The application claims priority to the Chinese patent
application No. 201610179872.8, filed Mar. 25, 2016, the disclosure
of which is incorporated herein by reference as part of the
application.
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