1. Tech Focus
32 June 2015 | Electronics For You www.efymag.com
Hybridisation and Thin-Film Sensors Key
Enablers of Flexible Electronics Today
F
lexible electronics is making its pres-
ence felt in almost every field, be
it wearable, consumer electronics,
medical, industrial or lighting. Still in early
development, printed and flexible electron-
ics is also enabling a much-talked-about
trend today—the Internet of Things (IoT).
Let us take a look at the latest happenings
in the area, sneak-peak into the research
and development activities and some inter-
esting examples of commercial applications
and applications currently under active
research.
Large-area and low-cost integration
giving rise to real-life applications
In the past year, we continued to see in-
creased interest in the capabilities and
technologies related to printed electron-
ics. Printed electronics continues to fit the
profile of an emerging technology space
as awareness and participation in the area
grows. “State-of-the-art capabilities of flex-
ible and printed electronics include logic
and memory devices, displays and lighting,
thin-film batteries, photovoltaics as well as
a multitude of sensors,” says Luisa Petti,
PhD student, Wearable Computing Labora-
tory, Swiss Federal Institute of Technology
Zurich.
Petti adds, “Recently, efforts have also
moved towards large-area and low-cost
integration of all these devices into fully-
flexible or stretchable systems.” Therefore
more and more real-life
system applications are
being proposed and dem-
onstrated.
It is important to dis-
tinguish between hybrid
integration of rigid con-
ventional silicon based
electronics with flexible
electronics and fully-
flexible printed systems using only low-
temperature materials. Petti says, “On one
side, the hybrid approach allows taking
advantages of the high performance of
rigid silicon technology and at the same
time expands its applications using flexible
electronics technology.”
A few examples of systems developed
employing this hybrid approach are LG G
Flex mobile phone, Apple Watch and MC10
Biostamp.
Listed below are some other select ex-
amples that show the versatility of printed
electronics.
Sleep mask for prevention of diabetic
disease. Niche applications are starting to
become more apparent within a range of
high-value market sectors. Development of
a healthcare application that utilises plastic
electronics is one such example.
PolyPhotonix, based at Centre for Pro-
cess Innovation (CPI), has developed a
light-therapy sleep mask, Noctura 400, for
the prevention and treatment of diabetic
retinopathy, a disease caused by diabetes.
It is one of the most common causes of
blindness in the western world, informs
Steven Bagshaw, marketing executive, CPI.
Designed as a monitored home based
therapy, the sleep mask offers a patient-
centric, non-invasive treatment that can
be delivered at a fraction of the cost of the
current interventions—laser photocoagula-
tion surgery or intraocular drug injection.
Bagshaw says, “With 3.5 million diabetes
sufferers in Britain, the technology has the
potential to save National Health Service
(NHS) £1 billion per year upon adoption.”
He adds, “The key message for flex-
ible electronics from the success of Poly-
Photonix is that the company identified a
game-changing market application where
functional benefits of plastic electronics
added significant value to the product.
Abhishek A. Mutha
is a senior technical
correspondent at EFY
The Noctura 400 Sleep Mask
(Image courtesy: dailymail.co.uk)

2. Tech Focus
34 June 2015 | Electronics For You www.efymag.com
Also, current technological obstacles
that are apparent in plastic electron-
ics were not detrimental to the com-
mercialisation of the product.”
Sensor to monitor head impacts
in sports. In the last one year or so,
the scenario of flexible electronics
has rapidly changed. “Main driving
applications in this field are related
to flexible, rollable, foldable and
paperlike displays for the consumer
electronics industry,” notes Petti.
Wearable applications with flex-
ible electronics are envisioned not
only in the huge display industry but
also in the healthcare sector. Here,
MC10 is shaping the field with its
ultra-thin flexible skin sensor patch,
Biostamp.
An interface between human
and electronics, Biostamp is a seam-
less sensing soft sticker, capable
of stretching, flexing and moving
with the body. Powered by thin-film
battery technology, this sensor can
measure a variety of physiologi-
cal functions such as data from the
heart, muscles, brain, body tempera-
ture and body movement.
Biostamp has been used com-
mercially in Reebok’s CHECKLIGHT,
a head-impact indicator that uses a
multiple of these sensors to capture
head-impact data during play when
athletes are unaware of the severity
of a blow to the head.
Lighting system that uses flex-
ible circuitry. Cohda, a UK based
design studio, has worked with
CPI on the integration of printed
electronics to significantly enhance
the functionality of their wireless
Crypsis Lighting product, developing
the product from prototype to full
commercial manufacture. Crypsis
Lighting offers wireless ultra-bright
LEDs that can be repositioned and
dimmed within a transparent glass
panel using an external magnetic
control puck. The system is a fully-
interactive low-voltage lighting unit
and is currently being used within
a diverse range of products and
markets such as interior design,
exhibition design, museum, retail,
architecture and contempo-
rary lighting.
Earlier, Crypsis Light-
ing utilised silicon based
electronics for their lighting
units. Bagshaw says, “Due
to the rigid nature of the
circuitry, Cohda encoun-
tered a number of issues in
research and development
including the transfer of
power to the light units
and voltage drop with the
electronics within the light
units.”
He adds, “CPI worked
with Cohda to use printed
electronics to bring flexibil-
ity and conformability into
the design of their light unit
device. These properties
enabled the electronics to
conform to the surface con-
tact of the glass, resulting in
the elimination of voltage
drop and an increase in
conductivity levels.”
Pure-copper-conductive
ink for the wearable world.
In November 2014, DuPont
Microcircuit Materials (DuPont) in-
troduced their PE510 photonic copper
product. PE510 is a cost-effective al-
ternative to silver-conductor inks for
a variety of possible applications, and
is the newest product in a suite of
conductive ink materials specifically
tailored for use in certain types of
antennae, membrane touch switches
(MTSes), radio frequency identifica-
tion (RFID) and consumer electronics
applications.
Stan Farnsworth, VP - marketing,
NovaCentrix, says, “This electrically-
conductive ink is designed for use
on polymeric substrates and reaches
optimal performance when processed
with PulseForge photonic curing
tool from NovaCentrix.” These inks
provide designers with higher flex-
ibility to design antennae, enabling
a lower total manufacturing cost,
while meeting electrical performance
requirements.
Technologies enabling commercial flexible products today
The technologies currently available commercially include flexible thin-film transistors and
logic circuits (with amorphous silicon, organic, metal-oxide, low-temperature polycrystalline
silicon semiconducting materials), flexible organic light emitting diode (OLED) based
displays, flexible memories and batteries, as well as flexible photovoltaics and sensors.
Additionally, many types of flexible and transparent conductors are also available
commercially, ranging from indium-tin-oxide (ITO) to nanotubes and nanowires. All these
materials and technologies are mature, and the devices based on these are commercially
available and ready to be integrated into more complex flexible systems that can enable a
wide range of applications.
—Luisa Petti, PhD student, Wearable Computing Laboratory,
Swiss Federal Institute of Technology, Zurich
CPI worked with Cohda to use printed electronics to bring
flexibility and conformability into the design of their wireless
device Crypsis Lighting (Image courtesy: www.uk-cpi.com)
A player wearing Reebok Checklight, a skullcap with sensors
to monitor head impacts during play
(Image courtesy: thechronicleherald.ca)

3. Tech Focus
36 June 2015 | Electronics For You www.efymag.com
Sensor that could revolutionise
industrial and consumer electronics.
The fully-flexible approach targets
a more unobtrusive and large-area
integration of developed systems. A
great example of this latter approach
includes the multi-awarded image
sensor on plastic, unveiled by ISORG
and Plastic Logic, which combines
the flexible large-area photodetec-
tor technology from ISORG and the
organic thin-film technology from
Plastic Logic.
This opens the way to new ap-
plications, ranging from smart pack-
aging, sensor tags for medical and
biomedical applications, security
and mobility commerce,
to environmental and
industrial electronics.
Fascinating research
and development
happening
One of the most chal-
lenging goals for flexible
electronics is to achieve
lightweight and unob-
trusive devices, notes
Giuseppe Cantarella,
PhD student, Wearable
Computing Laboratory,
Swiss Federal Institute
of Technology, Zurich.
Keeping high electrical
performances in mind,
researchers are now tak-
ing big steps forward to
integrate with respect to customers’
attitudes and requirements.
He says, “The new trends now
go in specific directions to fulfil
the market focus. One of these is
bio-compatibility for implantable
devices that can remotely monitor
and improve our healthcare, provide
mechanical and electrical stability
over time and low cost for the devel-
opment of a technology that is acces-
sible to most.”
Materials and manufacturing
techniques are the two main areas
for research. The main focus of re-
search activities in universities and
research centres in the field of print-
able and flexible electronics is in two
main directions: the development
of new materials with better perfor-
mances and low-cost deposition, and
the study of new technologies and
manufacturing techniques on plastic
substrates with superior mechanical
properties.
“Since next-generation electron-
ics is expected to be conformal to
any surface including human skin
or human tissues, many efforts
have been devoted to establish en-
gineered techniques for conformal
electronics,” Cantarella says. A great
example of this approach has been
demonstrated by the group of Prof.
Someya of Tokyo University, where
implantable bio-compatible devices
have been realised using organic
semiconductors.
In parallel to the development of
graphene, nanotubes and 2D materi-
als, new material formulations have
been introduced. A very new and
interesting work is the one on printed
liquid silicon on paper, demonstrated
by the Delft team, led by Prof. Ishi-
hara at Delft University of Technol-
ogy. These results could lead to high-
performance and low-cost printed
and flexible transistors and circuits.
Smart contact lens to inform
diabetic patients on blood-glucose
levels. A brilliant example of tack-
ling a growing problem of diabetes
using flexible and printed electron-
ics is Google’s Smart Contact Lens
project, co-developed by Google and
Novartis.
Uncontrolled blood sugar poses
a threat to people’s lives and could
damage their eyes, kidneys or heart
in the long run. People with diabetes,
more often than not, have fluctuat-
ing glucose levels. Sudden spikes
or drops are dangerous. To monitor
the blood-glucose level, people with
diabetes need to prick their finger
and test drops of blood at regular
intervals throughout the day.
In hopes of finding easier meth-
ods to measure glucose body levels,
scientists have been researching on
an alternate, non-invasive way in
Hybridisation is another key enabler of
today’s printed and flexible electronics
Hybridisation is a key word in the printed electronics space right now. It is the combination
of traditional electronics technologies and components with newer printed electronics
technologies. Innovative companies such as American Semiconductor in Boise, Idaho, are
offering new flexible silicon based processors for use in wearables and other applications.
PragmatIC in the UK continues to move ahead with organic based processors, and
Thin Film Electronics based in Norway is regularly in the news for applications utilising their
printed memory.
Each of these companies is working with methods to attach their products into more
complex circuit designs, utilising both existing and new connection technologies such as
solder or conducting adhesives.
Ohmatex in Denmark has spent extensive time developing successful means to connect
electronics with textiles for applications ranging from sports and athletic use to industrial and
first-responder safety gear. Products for these groups range from various forms of wearable
devices to new applications of near-field-communication/sensor combinations.
—Stan Farnsworth, VP - marketing, NovaCentrix
Plastic Logic and ISORG’s sensor which promises to transform
the way we interact with consumer devices
(Image courtesy: www.isorg.fr)

4. Tech Focus
38 June 2015 | Electronics For You www.efymag.com
the form of measuring tears. With
the help of miniaturised electronics,
Google is testing a smart contact lens
to measure glucose levels in tears
using a tiny wireless chip and min-
iaturised glucose sensor embedded
between two layers of soft contact
lens material.
This novel contact lens will con-
What is happening in India
With the aim to accelerate the development of flexible electronics industry in the country,
Department of Electronics and Information Technology (DeitY), Ministry of Communication
and Information Technology (MCIT), government of India, has established a centre of
excellence for large-area flexible electronics (FlexE Centre) at IIT Kanpur. A dedicated team
of 50 researchers and project staff will be working under the mentorship of IIT Kanpur’s
faculty members from different departments. Its current objectives include development
of a national technology roadmap in association with academia, industry and public
research organisations in the country, establishment of a broad research and development
programme that serves as a foundation for development of domestic industry in this field.
tain a low-power microchip
and a transparent ultra-
thin and flexible electronic
circuit, and will be used
to measure blood-sugar
levels of diabetes sufferers.
Although these are still
early days, Google is also
planning to explore the pos-
sibility of integrating tiny
LED lights to indicate to the
user that glucose level has
crossed or dropped below a
certain threshold level.
Focus on hybrid and
purely flexible systems.
Most recently, research has
also shifted towards system
integration, notes Petti. Sys-
tem integration is develop-
ing in both the directions of
hybrid integration of rigid
conventional silicon tech-
nology with flexible/printed
electronics, as well as the
realisation of fully-flexible
and/or printable platforms.
The best examples of
hybrid system integration
can be surely found in
the research done by Prof.
Rogers at University of Illi-
nois. Areas include flexible,
stretchable, epidermal and
biodegradable sensors and
circuits using conventional silicon
technology and unconventional sub-
strates and architectures.
On the other side, a notable ex-
ample of the fully-flexible approach
includes the work by ETH Zürich (or
Swiss Federal Institute of Technology
Zurich) on lightweight and transpar-
ent metal-oxide electronics that can
wrap around a human hair. This can
lead to fully-flexible and transparent
smart contact lenses, as well as many
other biomedical applications.
In the field of fully-flexible sys-
tem integration, the biggest players
are Interuniversity Microelectronics
Centre (IMEC) and Holst Center,
who offer an extensive organic
and metal-oxide based technol-
ogy for flexible thin-film transistors,
circuits, photovoltaics and active-
matrix organic light emitting diode
(AMOLED) displays.
Notable universities involved in
research. Globally, key universities
in this field are almost too numerous
to name with each group working
on topics ranging from fundamental
science all the way to final product
characterisation and prove-out, feels
Farnsworth.
He says, “Other than California
Polytechnic State University, some
other groups doing important work
in the area include CPI in the UK,
Cetemmsa Technological Centre near
Barcelona, Spain, VTT Technical
Research Centre in Finland, Fraun-
hofer group in Germany, Industrial
Technology Research Institute (ITRI)
in Taiwan, The National Institute
of Advanced Industrial Science and
Technology (AIST) in Japan and
EMSE near Marseilles, France.”
He adds, “Dr Denis Cormier at
Rochester Institute of Technology in
Rochester, New York, is doing work
combining printed electronics tech-
nologies with the still-developing
additive manufacturing space.”
Flexible electronics will make
a ripple in every possible field
From healthcare monitoring, wear-
able and skin-like electronics, smart
packaging, sensory tags for medical
and biomedical applications, security
and mobility commerce to environ-
mental and industrial electronics,
many novel applications are being
envisioned. Petti says, “This is all
enabled by the unique selling points
of flexible and printable electronics,
which include its mechanical flex-
In association with pharmaceutical giant Novartis, Google
is developing a smart contact lens to help patients manage
diabetes. Apparently, Google has been granted a patent for
the same (Image courtesy: www.forbes.com)
High-mobility polysilicon layer was directly formed on paper by
coating liquid silicon, which was annealed by pulsed laser-light
by Prof. Ishihara and team at Delft University of Technology
(Image courtesy: http://optics.org)

5. Tech Focus
39www.efymag.com Electronics For You | June 2015
Major contributors to this report
Giuseppe
Cantarella,
PhD student, Wearable
Computing Laboratory,
Swiss Federal Institute of
Technology, Zurich
Luisa Petti,
PhD student, Wearable
Computing Laboratory,
Swiss Federal Institute of
Technology, Zurich
Stan Farnsworth,
VP - marketing,
NovaCentrix
Steven Bagshaw,
marketing executive,
Centre for Process
Innovation Ltd
ibility, large-area manufacturing and
potential low-cost in volume.”
According to Cantarella, for print-
ed and flexible electronics, the most
challenging sector will be medical.
He says, “The devices included in
this field should be bio-compatible
and sufficiently reliable for medical
care in order to be able to gener-
ally improve healthcare and monitor
physical conditions.”
“Even more challenging is the
idea to implant such devices for
real-time analysis such as digestible
electronic components that can be
dissolved in the human body,” adds
Cantarella.
PragmatIC Printing holds a great
deal of potential for the production
of new exciting applications within
the packaging sector and the develop-
ment of the IoT.
Bagshaw notes, “The company is
developing ultra-thin and low-cost
flexible microcircuits that can be
easily incorporated into mass-market
packaging, and will revolutionise
everyday living by providing con-
sumers with real-time information
about every aspect of their environ-
ment.”
He adds, “Hybrid electronics
will give rise to a wide range of
new, novel applications such as
flexible displays for mobile devices,
smart therapeutic bandages for
managing and monitoring recovery
of wounds, wearable electronics for
monitoring and improving perfor-
mance, wireless medical devices
for rapid diagnostics using printed
sensors, conformable lighting and
intelligent packaging for consumer
goods and industrial products, to
name a few.”
At a printed electronics confer-
ence in the USA, it was predicted
that the overall market for printed
and flexible sensors is forecast to be
worth over US$ 7 billion by 2020. 