U.S. patent application number 14/792866 was filed with the patent office on 2016-07-21 for stretchable display device.
The applicant listed for this patent is SAMSUNG DISPLAY CO., LTD.. Invention is credited to Chi-O CHO, Jae Joong KWON, Sang-Il PARK.
Application Number | 20160211471 14/792866 |
Document ID | / |
Family ID | 56321151 |
Filed Date | 2016-07-21 |
United States Patent
Application |
20160211471 |
Kind Code |
A1 |
KWON; Jae Joong ; et
al. |
July 21, 2016 |
STRETCHABLE DISPLAY DEVICE
Abstract
An exemplary embodiment provides a stretchable display device
which is stretched in at least one direction. The stretchable
display device according to the exemplary embodiment includes a
stretchable substrate, a display unit, a plurality of rigid lenses,
and a transparent elastic part. The display unit is on the
stretchable substrate, and includes a plurality of light sources
and a plurality of stretchable electrodes. The rigid lenses are
disposed to correspond to the plurality of light sources,
respectively. The transparent elastic part encloses the plurality
of rigid lenses on the display unit and is stretched along with the
stretched substrate and when being stretched, forms lens surfaces
corresponding to the plurality of rigid lenses, respectively.
Inventors: |
KWON; Jae Joong; (Suwon-si,
KR) ; CHO; Chi-O; (Gwangju, KR) ; PARK;
Sang-Il; (Yongin-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG DISPLAY CO., LTD. |
Yongin-City |
|
KR |
|
|
Family ID: |
56321151 |
Appl. No.: |
14/792866 |
Filed: |
July 7, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02E 10/549 20130101;
H01L 51/5275 20130101; H01L 51/5253 20130101; H01L 2251/5338
20130101; H05K 1/0283 20130101; H01L 33/62 20130101; H01L 27/3288
20130101; H01L 51/5237 20130101; H01L 25/0753 20130101; H01L
51/0097 20130101; H01L 51/5203 20130101; G06F 1/1652 20130101; H05K
2201/10106 20130101 |
International
Class: |
H01L 51/00 20060101
H01L051/00; H01L 33/40 20060101 H01L033/40; H01L 51/52 20060101
H01L051/52; H01L 33/52 20060101 H01L033/52; H01L 33/62 20060101
H01L033/62; H01L 27/32 20060101 H01L027/32; H01L 27/15 20060101
H01L027/15; H01L 33/58 20060101 H01L033/58 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 15, 2015 |
KR |
10-2015-0007619 |
Claims
1. A stretchable display device, comprising: a stretchable
substrate having at least a portion of a stretched area; a display
unit on the stretched area, the display unit including a plurality
of light sources and a plurality of stretchable electrodes; a
plurality of rigid lenses disposed to correspond to the plurality
of light sources; and a transparent elastic part enclosing the
plurality of rigid lenses on the display unit and stretched along
with the stretched area, and, when stretched, form lens surfaces
corresponding to the plurality of rigid lenses, respectively.
2. The stretchable display device as claimed in claim 1, wherein: a
difference between a refractive index of the transparent elastic
part and a refractive index of the rigid lens is equal to or less
than 0.3.
3. The stretchable display device as claimed in claim 2, wherein:
in an initial state in which the transparent elastic part is not
stretched, the transparent elastic part has a flat surface opposite
the stretchable substrate.
4. The stretchable display device as claimed in claim 1, wherein:
the plurality of light sources include any one of an organic light
emitting diode and an inorganic light emitting diode.
5. The stretchable display device as claimed in claim 1, wherein:
the plurality of stretchable electrodes are each made of conductive
polymer having an elastic force.
6. The stretchable display device as claimed in claim 1, wherein:
the plurality of stretchable electrodes each include a plurality of
light source fixing parts and a variable part that connects between
two adjacent light source fixing parts.
7. The stretchable display device as claimed in claim 6, wherein: a
distance between the light source fixing parts increases while the
variable part is extended by an external force applied to the
stretchable substrate.
8. The stretchable display device as claimed in claim 6, wherein,
in an initial state, the variable part has more length than needed
to linearly connect two adjacent light source fixing parts.
9. The stretchable display device as claimed in claim 8, wherein
the variable part includes a metal strip.
10. The stretchable display device as claimed in claim 1, wherein:
the plurality of rigid lenses are disposed to correspond to the
plurality of light sources, respectively.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] Korean Patent Application No. 10-2015-0007619, filed on Jan.
15, 2015, in the Korean Intellectual Property Office, and entitled:
"Stretchable Display Device," is incorporated by reference herein
in its entirety.
BACKGROUND
[0002] 1. Field
[0003] The described technology relates generally to a display
device, and more particularly, to a stretchable display device
having a panel structure which may be expanded or contracted.
[0004] 2. Description of the Related Art
[0005] With the recent development of display device related
technologies, the display devices which may be changed in use, such
as being folding a screen in half, rolled in a roll form, and
stretched in at least one direction, have been researched and
developed. The changeable display device may meet dueling demands
to make a screen large while the display device is being used and
to make the screen small when the display device is not is being
used, e.g., to take up less space or to be portable.
[0006] Among the changeable display devices, there is a stretchable
display device which may be stretched in at least one direction.
The stretchable display device has a structure in which a plurality
of light sources and a plurality of stretchable electrodes are
disposed on the stretchable substrate. When the stretchable display
device is stretched, a gap between pixels is formed while an
interval between the light sources is increased. That is, since the
interval between the light sources is increased in a state (fixed
resolution) in which the number of light sources is fixed, a
pixel-fill factor is reduced, deteriorating image quality.
[0007] The above information disclosed in this Background section
is only for enhancement of understanding of the background of the
described technology and therefore it may contain information that
does not form the prior art that is already known in this country
to a person of ordinary skill in the art.
SUMMARY
[0008] An exemplary embodiment provides a stretchable display
device that includes a stretchable substrate, a display unit, a
plurality of rigid lenses, and a transparent elastic part. The
stretchable substrate may have at least a portion of a stretched
area. The display unit may be formed on the stretchable area and
include a plurality of light sources and a plurality of stretchable
electrodes. The plurality of rigid lenses may be disposed to
correspond to the plurality of light sources, respectively. The
transparent elastic part may enclose the plurality of rigid lenses
on the display unit and may be stretched along with the stretched
area and when being stretched, may form lens surfaces corresponding
to the plurality of rigid lenses, respectively.
[0009] A difference between a refractive index of the transparent
elastic part and a refractive index of the rigid lens may be equal
to or less than 0.3. The transparent elastic part may form a flat
surface in an initial state in which the transparent elastic part
is not stretched.
[0010] The plurality of light sources may include any one of an
organic light emitting diode and an inorganic light emitting diode.
The plurality of stretchable electrodes may be each made of
conductive polymer having an elastic force.
[0011] The plurality of stretchable electrodes may each include a
plurality of light source fixing parts and a variable part which
connects between two adjacent light source fixing parts and may be
made of a metal strip bent once or more. A distance between the
light source fixing parts may be expanded while the variable part
is unfolded by the external force.
[0012] In an initial state, the variable part may have more length
than needed to linearly connect two adjacent light source fixing
parts. The variable part may include a metal strip.
[0013] The plurality of rigid lenses may be disposed to correspond
to the plurality of light sources, respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Features will become apparent to those of skill in the art
by describing in detail exemplary embodiments with reference to the
attached drawings in which:
[0015] FIG. 1 illustrates a schematic cross-sectional view of a
stretchable display device according to the exemplary
embodiment.
[0016] FIG. 2 illustrates a perspective view of an exemplary
embodiment of a stretchable electrode in the stretchable display
device shown in FIG. 1.
[0017] FIG. 3 illustrates a schematic diagram of an optical path in
the stretchable display device of FIG. 1.
[0018] FIG. 4 illustrates a schematic cross-sectional view of a
state in which the stretchable display device of FIG. 1 is
stretched.
[0019] FIG. 5 illustrates a schematic diagram of light emission
distributions of light sources in the stretchable display device
shown in FIG. 1.
[0020] FIG. 6 illustrates a schematic diagram of the light emission
distributions of the light sources in the stretchable display
device shown in FIG. 4.
[0021] FIG. 7 illustrates a schematic diagram of light emission
distributions of light sources in a state in which a stretchable
display device of Comparative Example is stretched.
DETAILED DESCRIPTION
[0022] Hereinafter, the present disclosure will be described more
fully hereinafter with reference to the accompanying drawings, in
which exemplary embodiments of the disclosure are shown. As those
skilled in the art would realize, the described embodiments may be
modified in various different ways, all without departing from the
spirit or scope of the present disclosure.
[0023] Throughout the present specification, 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.
Further, in the specification, the word "on" means positioning on
or below the object portion, but does not essentially mean
positioning on the upper side of the object portion based on a
gravity direction.
[0024] 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. In addition,
the size and thickness of each configuration shown in the drawings
are arbitrarily shown for understanding and ease of description,
but the present disclosure is not limited thereto.
[0025] FIG. 1 is a schematic cross-sectional view of a stretchable
display device according to the exemplary embodiment. Referring to
FIG. 1, a stretchable display device 100 includes a stretchable
substrate 110, a display unit 120 formed on the stretchable
substrate 110, a transparent elastic part 130 formed on the display
unit 120, and a plurality of rigid lenses 140 positioned inside the
transparent elastic part 130.
[0026] The stretchable substrate 110 includes at least one portion
of a stretched area and the display unit 120 is on the stretched
area. The stretched area is stretched from an initial state in at
least one direction by an external force and may be restored to the
initial state when the external force is removed. For example,
stretchable substrate 110 may be made of a polymer material having
predetermined elasticity. The stretched area may be stretched in
one direction or may be stretched in two orthogonal directions. As
the stretched area is increased, a size of the display unit 120 is
also increased.
[0027] The display unit 120 includes a plurality of light sources
121 and a plurality of stretchable electrodes 122 connected to a
plurality of light sources 121. The plurality of light sources 121
may include an organic light emitting diode (organic LED) or an
inorganic light emitting diode (inorganic LED).
[0028] The typical light emitting diode includes an emission layer,
an anode supplying holes to the emission layer, and a cathode
supplying electrons to the emission layer. The electrons and the
holes are combined in the emission layer to generate excitons and
light is emitted by energy generated when the excitons drop from an
excited state to a ground state.
[0029] The light sources 121 of a single color may be distributed
over the whole of the display unit 120 such that each light source
121 serves as a pixel. Alternatively, the light sources 121 of at
least two colors may be distributed over the display unit 120. For
example, the display unit 120 may include a red light source, a
green light source, and a blue light source, and controls light
intensities of the red light source, the green light source, and
the blue light source, respectively, thereby implementing a
full-color image. That is, similar to the typical display device,
the red light source, the green light source, and the blue light
source each serve as a sub-pixel, with these three sub-pixels
serving as a pixel.
[0030] The stretchable electrode 122 electrically connects the
plurality of light sources 121 to an external circuit (printed
circuit board, and the like) to supply an electrical signal to the
light sources 121. The stretchable electrode 122 is stretched,
along with the stretchable substrate 110. To this end, the
stretchable electrode 122 may be made of a conductive polymer
material having predetermined elasticity or may be made of a
conductive strip, e.g., a metal strip, which is bent once or more,
and the like.
[0031] FIG. 2 illustrates a perspective view of an exemplary
embodiment of a stretchable electrode in the stretchable display
device shown in FIG. 1.
[0032] Referring to FIG. 2, the stretchable electrode 122 may
include a first electrode 123 and a second electrode 124 that
intersect each other, e.g., the first electrode 123 may extend
along the x direction, the second electrode may extend along the y
direction, and both may be orthogonal to the z direction, i.e. a
primary direction of the light emission or a viewing direction. The
first electrode 123 may be connected to any one of the anode and
the cathode of the light source 121 and the second electrode 124
may be connected to the other thereof. The first electrode 123 may
transfer a scan signal and the second electrode 124 may transfer a
data signal.
[0033] The first electrode 123 and the second electrode 124 may be
each configured of flat light source fixing parts 123a and 124a and
bent variable parts 123b and 124b which are positioned between two
adjacent light source fixing parts 123a and 124a. The variable
parts 123b and 124b may be formed in various patterns such as a
snaking pattern, i.e., meanderingly bent, a bow shape which is
convexly bent upward, and so forth. FIG. 2 illustrates an example
of the variable parts 123b and 124b having the snaking pattern. The
variable parts 123b and 124b may have any shape having excess
length, i.e., more material than needed to connect between two
adjacent light source fixing parts when connected in a linear
fashion, when the stretchable substrate 110 is in the initial
state, i.e., when the variable parts 123b and 124b, are in their
initial states, and the shapes and/or fully extended length thereof
may be different from one another.
[0034] When the stretchable substrate 110 is stretched, the
variable parts 123b and 124b are unfolded or otherwise extended
and, when, the stretchable substrate 110 returns to the initial
state, the variable parts 123b and 124b return to their initial
states. The stretchable electrode 122 is not limited to the
illustrated example and thereby may be variously changed. For
example, the bent variable parts 123b and 124b may include
sufficient material between light sources 121 to accommodate the
stretch of the stretchable substrate 100, i.e. the bent variable
parts 123b and 124b may fully or substantially fully extend, e.g.,
be partially or completely unbent, when the stretchable substrate
110 is fully stretched.
[0035] Referring again to FIG. 1, the display unit 120 is covered
with the transparent elastic part 130 and the plurality of rigid
lenses 140 are embedded in the transparent elastic part 130. The
number of rigid lenses 140 may be equal to the number of light
sources 121 and one rigid lens 140 may be disposed on each light
source 121. The rigid lens 140 is a lens made of a rigid material,
e.g, glass, and maintains a fixed shape regardless of the
stretching of the stretchable substrate 110.
[0036] The transparent elastic part 130 may be made of a polymer
material having excellent elastic force and restoring force, for
example, soft silicon resin or elastomer. The transparent elastic
part 130 has a smooth surface and is stretched together with the
stretchable substrate 110.
[0037] The transparent elastic part 130 has substantially the same
refractive index as that of the rigid lens 140. The refractive
index of the transparent elastic part 130 may be equal to that of
the rigid lens 140 or a difference between the refractive index of
the transparent elastic part 130 and the refractive index of the
rigid lens 140 may be equal to or less than 0.3. If the difference
between the refractive index of the transparent elastic part 130
and the refractive index of the rigid lens 140 is larger than 0.3,
refraction occurs at a boundary between the rigid lens 140 and the
transparent elastic part 130, making the targeted light emission
distribution difficult to obtain.
[0038] In the initial state in which the external force is not
applied to the stretchable display device 100, the transparent
elastic part 130 has a flat surface. FIG. 3 is a schematic
cross-sectional view additionally illustrating an optical path in
the stretchable display device of FIG. 1.
[0039] Referring to FIG. 3, the refractive index of the transparent
elastic part 130 is equal to that of the rigid lens 140 and the
transparent elastic part 130 has a flat surface and therefore light
emitted from the light source 121 is not refracted by the rigid
lens 140 and passes through the rigid lens 140 and the transparent
elastic part 130 as it is. That is, in the initial state, the rigid
lens 140 does not serve as the lens and the transparent elastic
part 130 and all of the plurality of rigid lenses 140 serve as a
transparent layer. In other words, the rigid lenses 140 are
effectively invisible, as the refractive index difference between
the transparent elastic part 130 and the rigid lenses 140 is
insufficient for the rigid lenses 140 to refract light incident
thereon.
[0040] FIG. 4 illustrates a schematic cross-sectional view of a
state in which the stretchable display device of FIG. 1 is
stretched.
[0041] Referring to FIG. 4, when the stretchable substrate 110 is
stretched in at least one direction, the light sources 121 are far
away from each other and the transparent elastic part 130 may be
stretched together with the stretchable substrate 110. In this
case, the surface of the transparent elastic part 130 is changed in
accordance with the shape of the rigid lens 140 and the transparent
elastic part 130 forms convex lens surfaces 135 corresponding to
each of the plurality of rigid lenses 140.
[0042] As the surface of the transparent elastic part 130 forming
the surface of the stretchable display device 100 is formed with
the convex lens surface 135, the light emitted from the light
source 121 is refracted on the lens surface 135 and is expanded. In
other words, the material of the transparent elastic part 130,
which now follows the contour of the rigid lenses 140, and the
rigid lenses together refract light at the boundary between the
lens surface 135 and the outside, e.g., air. Thus, the light is
refracted along the x and y directions to decrease apparent spacing
between the light sources 121. Therefore, the stretchable display
device 100 according to the exemplary embodiment may increase the
pixel-fill factor.
[0043] FIG. 5 is a schematic diagram illustrating light emission
distributions of light sources in the stretchable display device
illustrated in FIG. 3. Referring to FIGS. 3 and 5, the initial
state of the stretchable display device 100, the rigid lens 140
does not serve as the lens and therefore light having the same size
as the light source 121 is observed. That is, a size of a luminous
body 150 which is observed is equal to a size of the light source
121 and a distance between the luminous bodies 150 is equal to a
distance between the light sources 121.
[0044] FIG. 6 is a schematic diagram illustrating the light
emission distributions of the light sources in the stretchable
display device illustrated in FIG. 4. Referring to FIGS. 4 and 6,
as the stretchable display device 100 is stretched, the light
sources 121 are further from each other as compared to the initial
state and, as the transparent elastic part 130 forms the lens
surface 135, the light emitted from the light source 121 is
refracted on the lens surface 135 and is expanded to fill the area
between adjacent light sources.
[0045] Therefore, the size of the luminous body 150 which is
observed is larger than the light source 121, since a distance d1
between the luminous bodies 150 is smaller than an actual distance
d2 between the light sources 121. As a result, the gap between the
pixels is reduced in the state in which the stretchable display
device 100 is stretched to increase the pixel-fill factor, thereby
improving the image quality.
[0046] FIG. 7 is a schematic diagram illustrating light emission
distributions of light sources in a state in which a stretchable
display device of Comparative Example is stretched. The stretchable
display device according to Comparative Example is the same as a
configuration in which the transparent elastic part and the
plurality of rigid lens are omitted in the stretchable display
device of the exemplary embodiment.
[0047] Referring to FIG. 7, the stretchable display device of
Comparative Example does not have a diffusion means such as a lens
and therefore when the stretchable display device is stretched, the
size of the luminous body 150 which is observed is equal to the
size of the light source and the distance between the luminous
bodies 150 is equal to the distance between the light sources,
i.e., the actual distance d2. Therefore, in the stretchable display
device of Comparative Example, a large gap is generated between the
pixels to reduce the pixel-fill factor, which leads to the
deterioration in the image quality.
[0048] As described above, the stretchable display device 100
according to the exemplary embodiment compensates for the
deterioration of the pixel-fill factor as the distance between the
light sources 121 increases due to refraction of the lens surface
135, thereby reducing deterioration in image quality. In this case,
a curvature of the rigid lens 140 may be properly changed depending
on the observed distance and the expected degree of change of the
transparent elastic part 130 and the separate fixing means for
position alignment of light sources 121 the rigid lens 140 may be
provided.
[0049] The described technology has been made in an effort to
provide a stretchable display device capable of increasing a
pixel-fill factor in a state in which the stretchable display
device is stretched to reduce or prevent image quality from
deteriorating. When the stretchable display device is stretched and
thus the light sources are far away from each other, the lens
surface appears on the surface of the stretchable display device,
thereby expanding the light emitted from the light source.
Therefore, the gap between the pixels is reduced in the state in
which the stretchable display device is stretched to increase the
pixel-fill factor, thereby improving the image quality.
[0050] Example embodiments have been disclosed herein, and although
specific terms are employed, they are used and are to be
interpreted in a generic and descriptive sense only and not for
purpose of limitation. In some instances, as would be apparent to
one of ordinary skill in the art as of the filing of the present
application, features, characteristics, and/or elements described
in connection with a particular embodiment may be used singly or in
combination with features, characteristics, and/or elements
described in connection with other embodiments unless otherwise
specifically indicated. Accordingly, it will be understood by those
of skill in the art that various changes in form and details may be
made without departing from the spirit and scope of the present
invention as set forth in the following claims.
* * * * *