<s>
A	O
blue	B-Device
phase	I-Device
mode	I-Device
LCD	I-Device
is	O
a	O
liquid	B-Device
crystal	I-Device
display	I-Device
(	O
LCD	B-Device
)	O
technology	O
that	O
uses	O
highly	O
twisted	O
cholesteric	O
phases	O
in	O
a	O
blue	B-Device
phase	I-Device
.	O
</s>
<s>
It	O
was	O
first	O
proposed	O
in	O
2007	O
to	O
obtain	O
a	O
better	O
display	O
of	O
moving	O
images	O
with	O
,	O
for	O
example	O
,	O
frame	O
rates	O
of	O
100	O
–	O
120Hz	O
to	O
improve	O
the	O
temporal	O
response	O
of	O
LCDs	B-Device
.	O
</s>
<s>
This	O
operational	O
mode	O
for	O
LCDs	B-Device
also	O
does	O
not	O
require	O
anisotropic	O
alignment	O
layers	O
(	O
e.g.	O
,	O
rubbed	O
polyimide	O
)	O
and	O
thus	O
theoretically	O
simplifies	O
the	O
LCD	B-Device
manufacturing	O
process	O
.	O
</s>
<s>
For	O
almost	O
100	O
years	O
,	O
scientists	O
assumed	O
that	O
the	O
most	O
stable	O
cholesteric	O
helical	B-Application
structure	O
could	O
be	O
described	O
by	O
a	O
single	O
helical	B-Application
axis	O
about	O
which	O
the	O
director	O
rotates	O
.	O
</s>
<s>
It	O
turned	O
out	O
that	O
in	O
the	O
new	O
structure	O
the	O
director	O
rotates	O
in	O
a	O
helical	B-Application
fashion	O
about	O
any	O
axis	O
perpendicular	O
to	O
a	O
line	O
as	O
illustrated	O
in	O
fig	O
.	O
</s>
<s>
Although	O
an	O
unlimited	O
number	O
of	O
helical	B-Application
axes	O
are	O
actually	O
present	O
,	O
this	O
structure	O
was	O
named	O
double	O
twist	O
structure	O
.	O
</s>
<s>
This	O
double	O
twist	O
structure	O
is	O
more	O
stable	O
than	O
the	O
single	O
twist	O
structure	O
(	O
i.e.	O
,	O
the	O
normal	O
helical	B-Application
structure	O
of	O
chiral	O
nematics	O
)	O
only	O
up	O
to	O
a	O
certain	O
distance	O
from	O
the	O
line	O
at	O
the	O
center	O
.	O
</s>
<s>
Since	O
this	O
distance	O
is	O
on	O
the	O
order	O
of	O
the	O
pitch	O
of	O
the	O
chiral	O
nematic	O
liquid	B-Device
crystal	I-Device
(	O
typically	O
100nm	O
)	O
and	O
since	O
the	O
geometries	O
of	O
usual	O
liquid	B-Device
crystal	I-Device
samples	O
are	O
much	O
larger	O
,	O
the	O
double	O
twist	O
structure	O
occurs	O
only	O
rarely	O
.	O
</s>
<s>
Blue	B-Device
phases	I-Device
are	O
special	O
cases	O
when	O
double	O
twist	O
structures	O
fill	O
up	O
large	O
volumes	O
.	O
</s>
<s>
Because	O
of	O
its	O
small	O
radius	O
,	O
such	O
a	O
cylinder	O
is	O
more	O
stable	O
than	O
the	O
same	O
volume	O
filled	O
with	O
a	O
single	O
twist	O
chiral	O
nematic	O
liquid	B-Device
crystal	I-Device
.	O
</s>
<s>
Blue	B-Device
phases	I-Device
are	O
thus	O
formed	O
by	O
a	O
regular	O
three-dimensional	O
lattice	O
of	O
defects	O
within	O
a	O
chiral	O
liquid	B-Device
crystal	I-Device
.	O
</s>
<s>
Since	O
the	O
spacings	O
between	O
the	O
defects	O
of	O
a	O
blue	B-Device
phase	I-Device
are	O
in	O
the	O
range	O
of	O
the	O
wavelength	O
of	O
light	O
(	O
several	O
hundred	O
nanometers	O
)	O
,	O
for	O
certain	O
wavelength	O
ranges	O
of	O
the	O
light	O
reflected	O
from	O
the	O
lattice	O
constructive	O
interference	O
occurs	O
(	O
Bragg	O
reflection	O
)	O
and	O
the	O
blue	B-Device
phase	I-Device
reflects	O
colored	O
light	O
(	O
note	O
that	O
only	O
some	O
of	O
the	O
blue	B-Device
phases	I-Device
actually	O
reflect	O
blue	O
light	O
)	O
.	O
</s>
<s>
In	O
2005	O
,	O
researchers	O
from	O
the	O
Centre	O
of	O
Molecular	O
Materials	O
for	O
Photonics	O
and	O
Electronics	O
at	O
the	O
University	O
of	O
Cambridge	O
reported	O
their	O
discovery	O
of	O
a	O
class	O
of	O
blue-phase	O
liquid	B-Device
crystals	I-Device
that	O
remain	O
stable	O
over	O
a	O
range	O
of	O
temperatures	O
as	O
wide	O
as	O
16-60	O
°C	O
.	O
</s>
<s>
The	O
researchers	O
showed	O
that	O
their	O
ultrastable	O
blue	B-Device
phases	I-Device
could	O
be	O
used	O
to	O
switch	O
the	O
color	O
of	O
the	O
reflected	O
light	O
by	O
applying	O
an	O
electric	O
field	O
to	O
the	O
material	O
,	O
and	O
that	O
this	O
could	O
eventually	O
be	O
used	O
to	O
produce	O
three-color	O
(	O
red	O
,	O
green	O
,	O
and	O
blue	O
)	O
pixels	O
for	O
full-color	O
displays	O
.	O
</s>
<s>
The	O
new	O
blue	B-Device
phases	I-Device
are	O
made	O
from	O
molecules	O
in	O
which	O
two	O
stiff	O
,	O
rod-like	O
segments	O
are	O
linked	O
by	O
a	O
flexible	O
chain	O
,	O
and	O
are	O
believed	O
to	O
be	O
stabilized	O
due	O
to	O
flexoelectricity	O
.	O
</s>
<s>
Furthermore	O
,	O
electro-optical	O
switching	O
with	O
response	O
times	O
of	O
the	O
order	O
of	O
10−4s	O
for	O
the	O
stabilized	O
blue	B-Device
phases	I-Device
at	O
room	O
temperature	O
has	O
been	O
shown	O
.	O
</s>
<s>
Blue	B-Device
Phase	I-Device
crystals	O
are	O
regarded	O
as	O
3D	O
photonic	O
crystals	O
,	O
as	O
they	O
possess	O
a	O
periodic	O
cubic	O
structure	O
in	O
the	O
nanometer	O
range	O
with	O
a	O
selective	O
bandgap	O
in	O
the	O
visible	O
wavelengths	O
.	O
</s>
<s>
However	O
,	O
standard	O
blue	B-Device
phase	I-Device
crystal	O
manufacturing	O
produces	O
polycrystalline	O
samples	O
,	O
the	O
single	O
crystal	O
size	O
being	O
in	O
the	O
micrometer	O
range	O
.	O
</s>
<s>
Recently	O
,	O
blue	B-Device
phases	I-Device
obtained	O
as	O
ideal	O
3D	O
photonic	O
crystals	O
in	O
large	O
volumes	O
have	O
been	O
stabilized	O
with	O
a	O
controlled	O
crystal	O
lattice	O
orientation	O
.	O
</s>
<s>
In	O
May	O
,	O
2008	O
Samsung	O
Electronics	O
announced	O
that	O
it	O
has	O
developed	O
the	O
world	O
's	O
first	O
Blue	B-Device
Phase	I-Device
LCD	B-Device
panel	I-Device
which	O
can	O
be	O
operated	O
at	O
an	O
unprecedented	O
refresh	O
rate	O
of	O
240Hz	O
.	O
</s>
<s>
Samsung	O
unveiled	O
a	O
15inch	O
prototype	O
model	O
of	O
its	O
Blue	B-Device
Phase	I-Device
LCD	B-Device
panel	I-Device
at	O
the	O
SID	O
(	O
Society	O
for	O
Information	O
Display	O
)	O
2008	O
international	O
Symposium	O
,	O
Seminar	O
and	O
Exhibition	O
,	O
which	O
was	O
held	O
in	O
Los	O
Angeles	O
from	O
May	O
18	O
to	O
23	O
,	O
2008	O
.	O
</s>
<s>
Developed	O
with	O
a	O
look	O
at	O
cost-efficiency	O
,	O
Samsung	O
's	O
Blue	B-Device
Phase	I-Device
mode	O
does	O
not	O
require	O
liquid	B-Device
crystal	I-Device
alignment	O
layers	O
,	O
unlike	O
today	O
's	O
most	O
widely	O
used	O
TFT	B-Device
LCD	I-Device
modes	O
such	O
as	O
Twisted	O
Nematic	O
(	O
TN	O
)	O
,	O
In-Plane	B-Architecture
Switching	I-Architecture
(	O
IPS	B-Architecture
)	O
or	O
Vertical	O
Alignment	O
(	O
VA	O
)	O
.	O
</s>
<s>
The	O
Blue	B-Device
Phase	I-Device
mode	O
can	O
make	O
its	O
own	O
alignment	O
layers	O
,	O
eliminating	O
the	O
need	O
for	O
any	O
mechanical	O
alignment	O
and	O
rubbing	O
processes	O
.	O
</s>
<s>
Additionally	O
it	O
has	O
been	O
claimed	O
that	O
Blue	B-Device
Phase	I-Device
panels	O
would	O
reduce	O
the	O
sensitivity	O
of	O
the	O
liquid	B-Device
crystal	I-Device
layer	O
to	O
mechanical	O
pressure	O
which	O
could	O
impair	O
the	O
lateral	O
uniformity	O
of	O
display	O
(	O
e.g.	O
</s>
<s>
In	O
a	O
blue	B-Device
phase	I-Device
based	O
LC-display	O
for	O
TV	O
applications	O
it	O
is	O
not	O
the	O
selective	O
reflection	O
of	O
light	O
according	O
to	O
the	O
lattice	O
pitch	O
(	O
Bragg	O
reflection	O
)	O
that	O
is	O
used	O
for	O
display	O
of	O
visual	O
information	O
,	O
but	O
an	O
external	O
electric	O
field	O
induces	O
a	O
birefringence	O
in	O
the	O
liquid	B-Device
crystal	I-Device
via	O
the	O
Kerr	O
effect	O
.	O
</s>
<s>
That	O
field	O
induced	O
birefringence	O
becomes	O
apparent	O
as	O
a	O
change	O
of	O
transmission	O
when	O
the	O
Blue	B-Device
Phase	I-Device
Mode	O
LC	O
layer	O
is	O
placed	O
between	O
crossed	O
polarizers	O
.	O
</s>
<s>
For	O
a	O
detailed	O
discussion	O
of	O
the	O
blue	B-Device
phase	I-Device
LCs	O
in	O
in-plane	B-Architecture
switching	I-Architecture
(	O
IPS	B-Architecture
)	O
structures	O
and	O
related	O
modeling	O
method	O
based	O
on	O
the	O
Kerr	O
effect	O
in	O
a	O
macroscopic	O
scale	O
see	O
references	O
.	O
</s>
<s>
With	O
an	O
isotropic	O
dark	O
state	O
,	O
blue	B-Device
phase	I-Device
LCDs	B-Device
show	O
many	O
interesting	O
electro-optic	O
performances	O
.	O
</s>
<s>
Presently	O
,	O
the	O
driving	O
voltage	O
of	O
blue	B-Device
phase	I-Device
LCs	O
in	O
IPS	B-Architecture
structures	O
is	O
still	O
a	O
little	O
bit	O
too	O
high	O
.	O
</s>
