U.S. patent application number 15/176732 was filed with the patent office on 2016-09-29 for microcup compositions.
The applicant listed for this patent is E INK CALIFORNIA, LLC. Invention is credited to Yu LI, HongMei ZANG.
Application Number | 20160279072 15/176732 |
Document ID | / |
Family ID | 50773501 |
Filed Date | 2016-09-29 |
United States Patent
Application |
20160279072 |
Kind Code |
A1 |
LI; Yu ; et al. |
September 29, 2016 |
MICROCUP COMPOSITIONS
Abstract
The present invention is directed to a composition for preparing
the microcups and the toughness of the display panel formed from
such a composition may be significantly improved. In some cases,
the panel may have an elongation at break of more than 10% and it
can be completely peeled off from the substrate layer on which it
is formed, without causing any damage to the panel.
Inventors: |
LI; Yu; (Fremont, CA)
; ZANG; HongMei; (Fremont, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
E INK CALIFORNIA, LLC |
Fremont |
CA |
US |
|
|
Family ID: |
50773501 |
Appl. No.: |
15/176732 |
Filed: |
June 8, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13686778 |
Nov 27, 2012 |
9388307 |
|
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15176732 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 9/7092 20130101;
G02F 1/1681 20190101; B32B 2457/20 20130101; B32B 27/16 20130101;
G02F 1/167 20130101; B29C 2059/023 20130101; B32B 7/06 20130101;
B32B 2457/202 20130101; B32B 2307/20 20130101; C08L 33/06 20130101;
C08L 33/14 20130101; B29C 39/02 20130101; B32B 27/06 20130101; C09J
133/14 20130101; A61K 9/7084 20130101; A61J 1/16 20130101; B32B
7/12 20130101 |
International
Class: |
A61K 9/70 20060101
A61K009/70; C08L 33/06 20060101 C08L033/06; A61J 1/16 20060101
A61J001/16; C08L 33/14 20060101 C08L033/14 |
Claims
1. A panel comprising a plurality of microcups filled with a
functional fluid and sealed with a sealing layer, wherein the
microcups are formed from a composition comprising at least one
difunctional UV curable diacrylate or dimethacrylate material
selected from the group consisting of diethylene glycol diacrylate,
triethylene glycol diacrylate, tetraethylene glycol diacrylate,
polyethylene glycol diacrylate, ethoxylated bisphenol A diacrylate,
urethane diacrylate, ethoxylated bisphenol A dimethacrylate, and
polyethylene glycol dimethacrylate, wherein the total amount of the
at least one difunctional UV curable diacrylate or dimethacrylate
material is about 50-99% by weight of the composition, and wherein
the panel has a greater than 10% elongation at break.
2. The panel of claim 1, which has a greater than 20% elongation at
break.
3. The panel of claim 1, wherein the functional fluid comprises a
pharmaceutical composition.
4. The panel of claim 3, wherein the functional fluid comprises
about 0.01 wt % to about 40 wt % of the pharmaceutical
composition.
5. The panel of claim 1, further including an adhesive layer.
6. The panel of claim 1, wherein the difunctional UV curable
diacrylate or dimethacrylate material has a molecular weight higher
than about 200 Daltons.
7. The panel of claim 1, wherein the microcups are formed from
ethoxylated bisphenol A diacrylate or urethane diacrylate.
8. A panel comprising: (a) a plurality of microcups filled with a
functional fluid and sealed with a sealing layer, and (b) a primer
layer, wherein the microcups are formed from a composition
comprising at least one difunctional UV curable diacrylate or
dimethacrylate material selected from the group consisting of
diethylene glycol diacrylate, triethylene glycol diacrylate,
tetraethylene glycol diacrylate, polyethylene glycol diacrylate,
ethoxylated bisphenol A diacrylate, urethane diacrylate,
ethoxylated bisphenol A dimethacrylate, and polyethylene glycol
dimethacrylate, wherein the total amount of the at least one
difunctional UV curable diacrylate or dimethacrylate material is
about 50-99% by weight of the total composition, and wherein the
panel has a greater than 5% elongation at break.
9. The panel of claim 8, which has a greater than 15% elongation at
break.
10. The panel of claim 8, wherein the functional fluid comprises a
pharmaceutical composition.
11. The panel of claim 10, wherein the functional fluid comprises
about 0.01 wt % to about 40 wt % of the pharmaceutical
composition.
12. The panel of claim 8, further including an adhesive layer.
13. The panel of claim 8, wherein the difunctional UV curable
diacrylate or dimethacrylate material has a molecular weight higher
than about 200 Daltons.
14. The panel of claim 8, wherein the microcups are formed from
ethoxylated bisphenol A diacrylate or urethane diacrylate.
Description
[0001] This application is a Continuation of U.S. patent
application Ser. No. 13/686,778, filed Nov. 27, 2012; the contents
of which is incorporated herein by reference in its entirety.
BACKGROUND
[0002] U.S. Pat. No. 6,930,818 describes the microcup technology
for forming a display panel. According to the patent, microcups may
be formed by either a batchwise process or a continuous
roll-to-roll process. A composition for forming the microcups is
first coated on a substrate layer, followed by a microembossing or
photolithographic method. A preferred process is microembossing by
applying a male mold over the microcup composition to form
microcups. The microcup composition can also be coated onto the
male mold, followed by applying a substrate layer on top. The male
mold may be released during or after the microcup composition is
hardened.
[0003] The display panel formed is normally a very thin layer and
therefore fragile. Once it is formed on a substrate layer, the
microcup layer is very difficult to be peeled off from the
substrate layer without causing damage to the structure.
[0004] Prior to the present invention, a release layer was
considered to be added between a display panel and a substrate
layer, to facilitate separation of the display panel, if needed,
from the substrate layer after the display panel is formed on the
substrate layer. However, this approach had its disadvantages. For
example, the formation of the microcups by microembossing could
become difficult. This is due to the fact that when pulling the
mold from the partially cured microcups, with the presence of a
release layer between the display panel and the substrate layer,
the layers could be prematurely separated. Moreover, the mold could
also get stuck in the partially cured microcups to cause permanent
damage to the mold.
[0005] Another possible approach was to increase the thickness of
the bottom of the microcups, so that the microcups can withstand
the peel force for separating the display panel from the substrate
layer and avoid causing damage to the display panel. However in
this case, the thicker microcup bottom will cause more voltage drop
at the microcup bottom, which likely leads to insufficient voltage
for driving a display fluid contained within the microcups.
[0006] A further possible approach was to increase the thickness of
the partition walls separating the microcups. However, increasing
the thickness of the walls will decrease the fill factor, resulting
in unsatisfactory optical performance.
SUMMARY OF THE INVENTION
[0007] One aspect of the invention is directed to a display panel
comprising a plurality of microcups filled with a display fluid and
sealed with a sealing layer, which panel has a greater than 10%
elongation at break. In one embodiment, the panel has a greater
than 20% elongation at break.
[0008] Another aspect of the invention is directed to a display
panel comprising (a) a plurality of microcups filled with a display
fluid and sealed with a sealing layer, and (b) a primer layer,
which panel has a greater than 5% elongation at break. In one
embodiment, the display panel has a greater than 15% elongation at
break.
[0009] A further aspect of the invention is directed to a
composition for forming microcups, which comprises:
[0010] (a) at least one difunctional UV curable component;
[0011] (b) at least one photoinitiator; and
[0012] (c) at least one mold release agent.
[0013] In one embodiment, the difunctional UV curable component has
a molecular weight higher than about 200. In one embodiment, the
difunctional UV curable component is a difunctional acrylate. In
one embodiment, the difunctional acrylate has an urethane or
ethoxylated backbone. In one embodiment, the difunctional UV
curable component is diethylene glycol diacrylate, triethylene
glycol diacrylate, tetraethylene glycol diacrylate, polyethylene
glycol diacrylate, polyethylene glycol dimethacrylate, ethoxylated
bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate or
urethane diacrylate.
[0014] In one embodiment, the photoinitiator is bis-acyl-phosphine
oxide,
2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone,
2,4,6-trimethylbenzoyl diphenyl phosphine oxide,
2-isopropyl-9H-thioxanthen-9-one,
4-benzoyl-4'-methyldiphenylsulphide and
1-hydroxy-cyclohexyl-phenyl-ketone,
2-hydroxy-2-methyl-1-phenyl-propan-1-one,
1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one,
2,2-dimethoxy-1,2-diphenylethan-1-one or
2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one.
[0015] In one embodiment, the mold release agent is an
organomodified silicone copolymer.
[0016] In one embodiment, the composition further comprises a
co-initiator. In one embodiment, the composition further comprises
a monofunctional UV curable component. In one embodiment, the
composition further comprises a multifunctional UV curable
component. In one embodiment, the composition further comprises a
stabilizer.
[0017] Yet a further aspect of the invention is directed to a
device comprising a plurality of microcups formed from a
composition of the present invention, wherein the microcups are
filled with a functional material composition and sealed with a
sealing layer. In one embodiment, the functional material
composition is in the form of a liquid, such as an electrophoretic
fluid. In one embodiment, the functional material is a medicinal or
cosmetic agent. In one embodiment, the device further comprises a
primer layer.
[0018] Yet a further aspect of the invention is directed to a
method for the preparation of a display device, which method
comprises:
[0019] (a) forming a display panel comprising a plurality of
microcups from a composition of the present invention on a
substrate layer, filling the microcups with a display fluid and
sealing the filled microcups;
[0020] (b) separating the display panel from the substrate layer;
and
[0021] (c) laminating electrode layers onto both sides of the
display panel.
[0022] Yet a further aspect of the invention is directed to a
method for the preparation of a piezo display device, which method
comprises:
[0023] (a) forming a display panel comprising a plurality of
microcups from a composition of the present invention on a first
substrate layer, filling the microcups with a display fluid and
sealing the filled microcups;
[0024] (b) separating the display panel from the first substrate
layer;
[0025] (c) cutting the display panel into pieces of any dimensions
before or after step (b);
[0026] (d) transferring the pieces of the display panel onto a
second substrate layer with gaps between the pieces of display
panel; and
[0027] (e) filling the gaps with a piezo material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIGS. 1a and 1b depict general structures of microcup-based
panel on a substrate layer.
[0029] FIGS. 2a and 2b show the separation of a display panel from
a substrate layer.
[0030] FIG. 3 depicts a panel of the present invention.
[0031] FIGS. 4 and 5 illustrate a display device formed from a
panel.
[0032] FIG. 6 illustrates an alternative route of forming a display
device from a panel.
[0033] FIG. 7 shows an electrode layer along with a panel is
removed from a substrate layer.
[0034] FIG. 8 illustrates the use of a panel in forming a piezo
display device.
DETAILED DESCRIPTION OF THE INVENTION
[0035] The present inventors have now found a composition for
preparing microcups and the toughness of the panel formed from such
a composition may be significantly improved. In some cases, a panel
formed from such a composition may have an elongation at break of
more than 10% and the panel formed from it can be completely peeled
off from a substrate layer on which it is formed, without causing
any damage to the panel. The term "elongation at break" or
"elongation", in the context of the present invention, is expressed
as a percentage increase in length before one or both of the
following two conditions occur
[0036] (i) the loss of structural integrity of the microcups, such
as cracks or fissures becoming visually detectable, or
[0037] (ii) the leak of the liquid component filled in the
microcups becoming visually detectable.
[0038] In the context of the present application, the term "panel"
refers to a layer of microcups, filled with a functional material
composition (usually in a liquid form) and hermetically sealed with
a sealing layer. The panel does not include a substrate layer. The
panel, however, may include one or more dielectric layers, such as
a layer of a binder material, a layer of a matrix material, an
adhesive layer, a primer layer or any one of other
electrode-protecting layers, to provide support to the functional
material contained in the microcups. The panel may include a
conductor layer sandwiched in between the dielectric layers or
exposed on the outside.
[0039] FIG. 1a depicts a microcup-based panel on a substrate layer.
As shown, a panel (10) comprising microcups (10a) formed on a
substrate layer (11). It is optional to have a microcup bottom
(10b) which is formed from the same composition as the microcup
walls (10c). In the process of forming the panel, the microcups are
filled with a functional material composition. The functional
material composition may be a display fluid, a pharmaceutical
composition or the like.
[0040] If it is a display fluid, the fluid may be an
electrophoretic fluid comprising charged pigment particles
dispersed in a solvent or solvent mixture.
[0041] The filled microcups are then sealed with a sealing layer
(12) following a one-pass or two-pass procedure, according to U.S.
Pat. No. 6,930,818. In the one-pass method, a sealing composition
is pre-dispersed into a composition of a functional material and
the dispersion of the two compositions is coated onto the
microcups. The sealing composition is hardened during or after it
floats to the top of the functional material composition. In the
"two-pass" method, a functional material composition and a sealing
composition are sequentially coated into the microcups, followed by
hardening the sealing composition. In either method, the sealing
composition and the functional material composition are preferably
immiscible. The hardening of the sealing composition occurs in situ
(i.e., the sealing composition is being hardened when on top of the
functional material composition.)
[0042] The content of U.S. Pat. No. 6,930,818 is incorporated
herein by reference in its entirety.
[0043] There may be a primer layer (13) adjacent to the panel, as
shown in FIG. 1b.
[0044] The composition of the present invention comprises (a) at
least one difunctional UV curable component, (b) at least one
photoinitiator, and (c) at least one mold release agent.
[0045] a. Difunctional UV Curable Component
[0046] The total percentage of the difunctional UV curable
component(s) in the composition may range from about 10 wt % to
about 99 wt %, preferably from about 30 wt % to about 99 wt % and
more preferably from about 50 wt % to about 99 wt %. The
difunctional UV curable component has two reactive function
groups.
[0047] Suitable difunctional components for the present invention
may have a molecular weight higher than about 200. Difunctional
acrylates are preferred and difunctional acrylates having an
urethane or ethoxylated backbone are particularly preferred.
[0048] More specifically, suitable difunctional components may
include, but are not limited to, diethylene glycol diacrylate
(e.g., SR230 from Sartomer), triethylene glycol diacrylate (e.g.,
SR272 from Sartomer), tetraethylene glycol diacrylate (e.g., SR268
from Sartomer), polyethylene glycol diacrylate (e.g., SR295, SR344
or SR610 from Sartomer), polyethylene glycol dimethacrylate (e.g.,
SR603, SR644, SR252 or SR740 from Sartomer), ethoxylated bisphenol
A diacrylate (e.g., CD9038, SR349, SR601 or SR602 from Sartomer),
ethoxylated bisphenol A dimethacrylate (e.g., CD540, CD542, SR101,
SR150, SR348, SR480 or SR541 from Sartomer), and urethane
diacrylate (e.g., CN959, CN961, CN964, CN965, CN980 or CN981 from
Sartomer; Ebecryl 230, Ebecryl 270, Ebecryl 8402, Ebecryl 8804,
Ebecryl 8807 or Ebecryl 8808 from Cytec).
[0049] b. Photoinitiator
[0050] The total percentage of the photoinitiator(s) in the
composition may range from about 0.1 wt % to about 5 wt % and
preferably from about 0.4 wt % to about 2 wt %.
[0051] Suitable photoinitiators may include, but are not limited
to, bis-acyl-phosphine oxide,
2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone,
2,4,6-trimethylbenzoyl diphenyl phosphine oxide,
2-isopropyl-9H-thioxanthen-9-one,
4-benzoyl-4'-methyldiphenylsulphide and
1-hydroxy-cyclohexyl-phenyl-ketone,
2-hydroxy-2-methyl-1-phenyl-propan-1-one,
1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one,
2,2-dimethoxy-1,2-diphenylethan-1-one or
2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one.
[0052] c. Mold Release Agent
[0053] The percentage of the mold release agent in the composition
may range from about 1 wt % to about 10 wt % and preferably from
about 2 wt % to about 6 wt %.
[0054] Suitable mold release agents may include, but are not
limited to, organomodified silicone copolymers such as silicone
acrylates (e.g., Ebercryl 1360 or Ebercyl 350 from Cytec), silicone
polyethers (e.g., Silwet 7200, Silwet 7210, Silwet 7220, Silwet
7230, Silwet 7500, Silwet 7600 or Silwet 7607 from Momentive).
[0055] The composition may further optionally comprise one or more
of the following components, a co-initiator, monofunctional UV
curable component, multifunctional UV curable component or
stabilizer.
[0056] d. Co-Initiator
[0057] Co-initiator can be added to the composition to overcome
oxygen inhibition and improve surface curing speed. The percentage
of the co-initiator in the composition may range from 0 wt % to
about 20 wt % and preferably from about 5 wt % to about 10 wt
%.
[0058] Suitable co-initiators may include, but are not limited to,
amine functionalized acrylates, such as CN371, CN373, CN384US or
CN386US from Sartomer.
[0059] e. Monofunctional UV Curable Component
[0060] In the context of the present application, the term,
"monofunctional", is referred to as having one reactive function
group.
[0061] The percentage of the monofunctional UV curable components
in the composition may range from 0 wt % to about 80 wt % and
preferably from 0 wt % to about 40 wt %.
[0062] Suitable monofunctional UV curable components may include,
but are not limited to, methyl methacrylate, methyl acrylate, ethyl
methacrylate, ethyl acrylate, n-butyl acrylate, n-butyl
methacrylate, lauryl methacrylate, lauryl acrylate, 2-ethylhexyl
methacrylate, 2-ethylhexyl acrylate, methacrylic acid, acrylic
acid, hydroxyethyl methacrylate, hydroxyethylacrylate, styrene or
acrylate monomers from Sartomer, such as CD551, CD553, CD611,
CD9087, CD9088, SR256 or SR504.
[0063] f. Multifunctional UV Curable Component
[0064] In the context of the present application, the term,
"multifunctional", is referred to as having more than two reactive
function groups.
[0065] The percentage of the multifunctional UV curable components
in the composition may range from 0 wt % to about 80 wt % and
preferably from 0 wt % to about 40 wt %.
[0066] Suitable multifunctional UV curable components may include,
but are not limited to, trifunctional acrylates or methacrylates
(e.g., CD501, SR 415, SR444, SR454, SR499, SR502, CN972 or SR9035
from Sartomer), tetra- or penta-functional acrylates or
methacrylates (e.g., SR295, SR355, SR399, SR494 or SR9041 from
Sartomer), trifunctional urethane acrylates (e.g., CN929 from
Sartomer) or hexfunctional polyester acrylates (e.g., Ebecryl 830
from Cytec).
[0067] g. Stabilizer
[0068] Stabilizers can be added into the microcup composition to
ensure long term thermal and photo durability of the composition
after curing. The percentage of the stabilizers in the composition
may range from 0 wt % to about 10 wt % and preferably from 0 wt %
to about 5 wt %. Suitable stabilizers may include, but not limited
to, phenolic-, aminic-, sulphur-based and multifunctional
antioxidants, such as the Irganox.RTM. series supplied by BASF.
[0069] The microcups utilizing the present composition may be
prepared by microembossing, filled and sealed, as described in U.S.
Pat. No. 6,930,818.
[0070] The microcup layer (20) prepared from the present
composition may be easily separated without damage, from a
substrate layer (21) before filling as shown in FIG. 2a or after
filling and sealing as shown in FIG. 2b.
[0071] As stated above, there may be a primer layer adjacent the
panel. The primer layer is optional.
[0072] If the primer layer is extremely thin (e.g., <1 um) or no
primer layer at all, the mechanical strength of the panel
preferably has a >10% elongation and more preferably a >20%
elongation, after curing.
[0073] If the primer layer is relatively thick (e.g., 1.about.10
um), the mechanical strength of the panel derived from the microcup
composition described above may have a >5% elongation and
preferably a >15% elongation, after curing. The overall
mechanical strength for the panel and the primer layer has to meet
a >5% elongation and preferably a >10% elongation, after
curing.
[0074] The composition of a primer layer, if present, is at least
partially compatible with the microcup composition of the present
invention, after curing.
[0075] For example, the primer layer may be formed from a
composition comprising a polar oligomeric or polymeric material.
Such a polar oligomeric or polymeric material may be selected from
the group consisting of oligomers or polymers having at least one
of the groups such as nitro (--NO.sub.2), hydroxyl (--OH), carboxyl
(--COO), urethane (--NH--C(O)--O), urea (NH--C(O)--NH), alkoxy
(--OR wherein R is an alkyl group), halo (e.g., fluoro, chloro,
bromo or iodo), cyano (--CN), sulfonate (--SO.sub.3) or the
like.
[0076] The glass transition temperature of the polar polymer
material is preferably below about 100.degree. C. and more
preferably below about 60.degree. C.
[0077] The primer layer formed from such a composition preferably
has an average crosslinking density of below about 1 crosslink
point per 80 molecular weight and more preferably below about 1
crosslink point per 120 molecular weight. The suitable crosslinking
density can be achieved by incorporating polar polymeric materials
or polar oligomeric materials of different molecular weights in the
composition. For example, a polar oligomer having a relatively high
molecular weight may be blended with another polar oligomer having
a low molecular weight to achieve a desired crosslinking
density.
[0078] Examples of suitable polar oligomer may include, but are not
limited to, polyhydroxy functionalized polyester acrylates (such as
BDE 1025 from Bomar Specialties Co, Winsted, Conn.) or alkoxylated
acrylates, such as ethoxylated nonyl phenol acrylate (e.g., SR504
from Sartomer Company), ethoxylated trimethylolpropane triacrylate
(e.g., SR9035 from Sartomer Company) or ethoxylated pentaerythritol
tetraacrylate (e.g., SR494 from Sartomer Company).
[0079] Examples of suitable polar polymers may include, but not
limited to, solvent urethane polymers, such as Irostic.RTM.
polymers.
[0080] The polar oligomeric or polymeric material is compatible
with other components in the composition and can be easily
processed by simple mixing.
[0081] The weight percentage of the polar oligomeric or polymeric
material in the composition for the primer layer may be no less
than about 1%, preferably no less than about 3% and most preferably
no less than about 10%.
[0082] With such a composition, the primer layer having an intended
volume resistivity of about 1/1000 to about 100 times that of an
electrophoretic fluid filled in the microcups may be achieved. The
primer layer may have an intended volume resistivity of about
10.sup.7 to about 10.sup.12 ohm cm at 25.degree. C. and 40%
relative humidity.
[0083] Optionally, an adhesion promoter can be added to the primer
layer composition to ensure good adhesion to the microcup
structure. Such adhesion promoters may include, but are not limited
to, carboxylated acrylates, hydroxylated acrylate, metal acrylates
and the like, preferably at a concentration of about 0.1 wt % to
about 15 wt %.
[0084] Optionally, a photo-initiator for UV curing may also be
added in the primer layer composition, if UV curing is desired.
[0085] The panel of the present invention may be utilized in a
variety of ways. A few examples are provided below.
[0086] a) Display Device
[0087] In the case where the microcups are filled with a display
fluid (e.g., an electrophoretic fluid), the panel may utilized as
shown in the following examples.
[0088] A panel as shown in FIG. 3 has a sealing layer (30) side
(3a) and a non-sealing layer side (3b). Either side may be the
viewing side in a display device.
[0089] In FIG. 4, the sealing layer side (4a) is the viewing side.
In this case, a transparent electrode layer (42) is directly
deposited or transferred onto the sealing layer side of the panel
(40). The transparent electrode layer may be, but are not limited
to, ITO (indium tin oxide), carbon nano tube, PEDOT
[poly(3,4-ethylenedioxythiophene)] or silver nano wire. In this
assembly, on the opposite side (with or without a primer layer), an
adhesive layer (43) is added in order for a backplane (44) to be
attached to the panel.
[0090] In FIG. 5, the non-sealing layer side (5b) is the viewing
side. In this case, a transparent electrode layer (52) is directly
deposited or transferred onto the panel (50) or onto a primer layer
if there is a primer layer. In this assembly, an adhesive layer
(53) is added onto the sealing layer side (5a) in order for a
backplane (54) to be attached to the panel.
[0091] For the display assembly of FIG. 4 or 5, it is driven by the
voltage potential difference between the transparent electrode
layer and the backplane.
[0092] There is an option to directly deposit or transfer an
electrode layer onto both sides of the panel to from a simple
single pixel display or low resolution segment display. The
electrode on the viewing side has to be transparent. The electrode
on the back side (non-viewing side) can be opaque and made out of
conductive inks (such as silver ink or carbon black ink) which can
be directly printed onto the panel for forming a segment
display.
[0093] In a further example as shown in FIG. 6, a stack (60) of
layers is assembled. In the stack, there are a first substrate
layer (61), a first release layer (62), an electrode layer (63), an
adhesive layer (64), a second release layer (65) and a second
substrate layer (66). In assembling a display device, the first
substrate layer (61) and the first release layer (62) are removed
and a microcup panel (67) of the present invention is laminated
over the electrode layer (63). In another step which may be carried
out before or after the removal of the first substrate layer and
the first release layer, the second substrate layer (66) and the
second release layer (65) are removed, followed by adding an
auxiliary layer (68) through the adhesive layer (64). The auxiliary
layer may be a luminance enhancement layer as described in U.S.
Ser. No. 12/323,300 filed on Nov. 25, 2008, U.S. Ser. No.
12/323,315 filed on Nov. 25, 2008 and U.S. Ser. No. 12/397,917
filed on Mar. 4, 2009, color filters, anti-glare layer,
anti-scratch layer or the like. On the other side, a backplane (69)
is laminated to the panel (67) to complete the display device.
[0094] FIG. 7 depicts yet a further example. In this example, a
microcup panel (71) is formed on an electrode layer (72) which is
associated with a substrate layer (73). While the panel is peeled
off, the electrode layer will stay with the panel instead of the
substrate layer. This can be accomplished by carefully selecting a
substrate layer having an optimal surface energy between the
substrate layer and the electrode layer. In this case, ITO is not
preferred as the electrode layer due to its cracking behavior under
stress. Preferred electrode layer may be silver nano wire, carbon
nano tube, conductive polymers, such as PEDOT or the like.
Optionally, there is a protection layer (74) adjacent to the
electrode layer to protect the electrode layer during separation
and post processing.
[0095] It is also possible to have a primer layer adjacent to the
panel. In this example, the panel, the primer layer and the
electrode layer will be together while peeled off from the
substrate layer.
[0096] In yet a further example, a release layer may be present
between the panel and a substrate layer to further facilitate the
separation. If a primer layer is present between the panel and the
substrate layer, the primer layer adjacent to the panel can also be
released from the substrate layer with ease.
[0097] In a further example as shown in FIG. 8, a display panel of
the present invention, after being separated from the substrate
layer on which the panel is formed, may be transferred to another
substrate layer. In one embodiment, a panel (81) may be cut into
any dimensions before being transferred to another substrate layer
(82), and in this case, there may be gaps (83) left between the
pieces of the panel on the substrate layer (82) and the gaps may be
filled with a non-display material (84), such as a piezo
material.
[0098] b) Transdermal Delivery Device
[0099] The panel may also be used for pharmaceutical applications,
in particular used in a transdermal delivery device (e.g., plaster
or patch). Such a delivery device may be used for local or systemic
drug delivery. The pharmaceutical composition filled in the
microcups may comprise an active ingredient which may be a
medicinal or cosmetic agent. The medicinal agent may include
substances intended for use in the diagnosis, cure, mitigation,
treatment or prevention of diseases, or to affect the structure or
function of the body. The medicinal agent may be a single chemical
entity or a pharmaceutically acceptable salt thereof which will be
present in an amount such that the device delivers a
therapeutically effective amount for the disease or condition being
treated. The amount that constitutes a therapeutically effective
amount will vary, according to the type of the medicinal agent
used, the condition to be treated, any medicinal agents being
co-administered, the amount of time the composition is allowed to
remain in contact with the skin of the patient, and other factors
known to those of skill in the art.
[0100] The active ingredient present in the pharmaceutical
composition will generally be about 0.01 wt % to about 40 wt %,
preferably about 1.0 wt % to about 20 wt %, based on the total
weight of the composition.
[0101] Any drug that is suitable for transdermal delivery can be
used in the panel of the present invention. Examples of useful
drugs include, but are not limited to, anti-inflammatory drugs,
antibacterials, antiprotozoals, antifungals, coronary vasodilators,
calcium channel blockers, bronchodilators, enzyme inhibitors,
antihypertensives, anti-ulceratives, steroidal hormones,
antivirals, immunomodulators, local anesthetics, antitussives,
antihistamines, narcotic analgesics, peptide hormones, sex
hormones, enzymes, antinauseants, anticonvulsants,
immunosuppressives, psychotherapeutics, sedatives, anticoagulants,
analgesics, antiarrhythmics, antiemetics, contraceptives,
anticancer agents, neurologic agents, hemostatics, anti-obesity
agents, smoking cessation regimens or the like.
[0102] The composition for pharmaceutical applications may also
comprise excipients, such as a solvent, cosolvent, solubilizer,
solvent modifier, permeation enhancer, preservative, buffering
agent or the like. The solvent is the principal component of the
composition and preferably is one in which the active ingredient is
soluble or at least substantially soluble or can be made soluble or
become soluble, by addition of a cosolvent or solvent modifier.
Suitable solvents may be selected from any of the solvents normally
used for medicaments, cosmetics, nutrients or other active agents
to be delivered transdermally. Preferred solvents include lower
alcohols of from 2 to 6 carbon atoms, preferably from 2 to 4 carbon
atoms and may be monoalcohols, such as, ethanol, isopropanol or
sec-butanol, or polyols, such as, ethylene glycol, propylene
glycol, butylene glycol or glycerol. A mixture of solvents may also
be used. Other solvents, such as ketone (e.g., acetone or
methylethyl ketone), ethers (e.g., ethylether) may also be used, in
an amount which will be safe and non-toxic. While the solvent
system is generally non-aqueous, water may be used for water
soluble active ingredients and for those active ingredients which
are stable in the presence of and not denigrated by the presence of
water. When water is present in the solvent, in some cases, it will
usually constitute less than about 50 wt %, preferably less than
about 10 wt %, more preferably less than about 2 wt %, by weight of
the total solvent although more or less may be used, depending on
the active ingredient and as long as the objective of the invention
can be met.
[0103] Generally, the total amount of solvent(s) will be selected
to assure dissolution of the active ingredient and excipients and
provide suitable product viscosity. The amount of solvent(s)
falling within the range of from about 5 wt % to about 90 wt %,
preferably from about 25 wt % to about 75 wt %, based on the total
composition, may be used.
[0104] The composition filled in the microcups preferably is in the
form of a solution. However it is also possible to be in form of a
suspension/dispersion, emulsion, gel or the like.
[0105] For transdermal delivery applications, the active ingredient
permeates through the sealing layer at a desired rate. Diffusion of
the active ingredient through the sealing layer is dependent on
properties of the active ingredient, the solvent in which the
active ingredient is present, the chemical nature of the sealing
layer/adhesive layer or any other layers in between the active
ingredient and the skin. The rate of diffusion, in general, tends
to decrease with increased molecular volume. The rate of skin
penetration, on the other hand, is a function of the diffusion
coefficient, the barrier partitioning tendency, binding affinity
and the rate of metabolism of the active ingredient by the skin.
The sealing layer, in this application, is preferably a continuous
or microporous film. A continuous film may be prepared from, for
example, ethylene:vinyl acetate copolymers which may contain an
appropriate amount of vinyl acetate, for example, about 0.5 wt % to
about 40 wt %.
[0106] The panel formed on a substrate is removed (peeled off) from
the substrate layer on which it is formed and it is then
transferred to another film layer. The film layer, such as, an
elastic bandage coated with a pressure sensitive adhesive, is more
flexible than the substrate layer on which the panel is formed, and
therefore more suitable to be applied to skin for proper delivery
of the pharmaceutical composition in the panel.
EXAMPLES
Example 1 (Comparative)
Microcup Composition without Difunctional Components
[0107] 39.6 Parts by weight of Ebercryl 830 (Cytec), 51 parts of
SR-399 (Sartomer), 7 parts of Ebercryl 1360 (Cytec), 0.2 parts of
2,4,6-trimethylbenzoyl diphenyl phosphine oxide and 2.2 parts of
1-hydroxy-cyclohexyl-phenyl-ketone were mixed homogeneously and
used in the tensile strength test.
Example 2
Microcup Composition with Difunctional Components
[0108] 21 Parts by weight of Ebercryl 8808 (Cytec), 39.7 parts of
SR-602 (Sartomer), 25 parts of CD9038 (Sartomer), 4 parts of Silwet
7607 (Momentive), 9.86 parts of CN373 (Sartomer), 0.2 parts of
4-benzoyl-4'-methyldiphenylsulphide, and 0.24 parts of
2,4,6-trimethylbenzoyl diphenyl phosphine oxide were mixed
homogeneously and used for the tensile test.
Example 3
Tensile Test of Cured Microcup Materials
[0109] The microcup compositions of Examples 1 and 2 were coated
onto 5 mil PET film with a targeted dry thickness of about 100 um,
covered by PET release film, and then cured for 20 seconds under UV
light at an intensity of 5 mW/cm.sup.2. The PET cover sheet was
removed. The cured microcup layer was peeled off from the PET
substrate and cut into stripes with a width of 1.25 cm and a length
of 10 cm. The tensile test was then conducted by Instron at 50
mm/min. The results listed in Table 1 were the average of at least
5 measurements. The microcup composition containing difunctional
components showed much improved elongation at break and
toughness.
TABLE-US-00001 TABLE 1 Example 1 Example 2 Tensile Strength
(N/m.sup.2) 8.25 .times. 10.sup.6 3.95 .times. 10.sup.6 Elongation
at Break (%) 1.31 22.86 Toughness (J/m.sup.3) 5.37 .times. 10.sup.6
45.43 .times. 10.sup.6
Example 4
Tensile Test of Panel
[0110] The microcup composition of Example 2 was used to prepare
the microcup array with a thickness of around 27 um by
microembossing according to U.S. Pat. No. 6,930,818. The
electrophoretic fluid comprising charged pigment particles
dispersed in a hydrocarbon solvent was coated onto the microcup
array on a ITO/PET substrate film. The filled microcups are then
sealed with a sealing layer with a thickness of around 17 um,
following a one-pass procedure, according to U.S. Pat. No.
6,930,818. The microcup-based panel was then peeled off from the
ITO/PET substrate film and subjected to the tensile test as
described in Example 3.
[0111] The elongation was measured to be 18% before the microcup
structure was damaged.
[0112] This same test could not be carried out with the microcup
composition of Example 1 because the panel prepared from the
composition of Example 1 could not be separated from the ITO/PET
substrate film, without causing damages to the panel.
[0113] While the present invention has been described with
reference to the specific embodiments thereof, it should be
understood by those skilled in the art that various changes may be
made and equivalents may be substituted without departing from the
true spirit and scope of the invention. In addition, many
modifications may be made to adapt a particular situation,
materials, compositions, processes, process step or steps, to the
objective, spirit and scope of the present invention. All such
modifications are intended to be within the scope of the claims
appended hereto.
[0114] It is therefore wished that this invention to be defined by
the scope of the appended claims as broadly as the prior art will
permit, and in view of the specification.
* * * * *