Flexible 3D Circuits
Power Medical Devices
By Greg Kuchuris, Marketing Manager,
Printed Circuit Products, Molex Incorporated
As demand for healthcare continues to grow, medical practitioners are turning to
mobile-monitoring, therapeutic, and
diagnostic devices that can improve the
quality and efficacy of medical care.
As a result, medical devices have been
downsized, from bulky to portable to
handheld to wearable. Device manufacturers are selling their products to
increasingly tech-savvy clinicians and
patients who are accustomed to using
myriad portable and handheld electronic
devices. Having experienced the high
functionality of smart phones, for example, consumers expect the same from
medical devices with small form factors.
In some cases, these medical devices
and related communications devices have
become part of remote medical treat-
ment systems. For example, the practice
of “telehealth” uses digital information
and communication technologies, such
as computers and mobile devices, to
manage patients’ health and well-being.
Early detection of symptoms or changes
in physiology allows for preventative
measures and earlier treatment before a
patient’s health deteriorates or becomes a
Wearable technologies and other small
medical devices that provide continuous
real-time feedback help make telehealth
possible. Telehealth practitioners make use
of online health information and remote
patient communication facilitated by remote monitoring of health indicators, such
as blood glucose, blood pressure, heart
rhythm, pulse, and other vital signs, read
via sensors attached to or worn by a patient. These miniaturized real-time medical
monitoring devices can benefit patients
with chronic and potentially life-threat-ening conditions — and their healthcare
providers, who face mounting pressures to
improve outcomes, while reducing costs
and hospital readmission rates.
Compact medical devices are made
possible by lightweight circuitry that fits
within tight spaces. Anyone who has
packed a suitcase knows firsthand that
the contents must bend or flex in order
to maximize space and efficiency.
Among a number of proven technol-
ogies that have migrated from consumer
electronics into medical devices, flexible
circuits and flexible printed electronic
solutions help designers optimize space
in tightly packaged medical devices.
Products such as insulin pumps, wearable
patient monitoring devices, portable
defibrillators, and CPAP machines (used
to treat sleep and breathing disorders)
typically employ flex circuits.
Unlike conventional 2D circuits,
flexible printed circuits and printed
electronics occupy three dimensions and
can be bent around packaging, and even
folded over to fit in miniaturized device
enclosures. There are several other advantages. Flexible substrates with single-,
double-sided, and multi-layer circuitry
are ideal for high performance signal and
power connections at an economical
applied cost. Flex products can also be
mounted in through-hole, surface mount,
and press-fit configurations.
Flex circuits allow designers to make
electronic interconnection simpler and
more reliable. Unlike hard board materials containing woven glass fibers that
tend to result in signal loss, the materials
used in flex circuits, such as polyimide,
help maintain signal and power integrity.
Polyimide dissipates heat quicker, so the
flex circuit requires less cooling. Additionally, flex materials closely match thermal
expansion rates, which make them more
reliable in hot and cold temperature
extremes and temperature fluctuations
found in mobile healthcare applications.
Medical device miniaturization requires producers to adapt flex circuits for
3D packaging, tighter copper flex spacing,
and trace widths. As the device package
size shrinks, the flex circuit must also
shrink. Incorporating features like blind
and buried vias can help retain flexibility as the device package continues to
decrease in size.
Flexible printed circuit interconnects offered by Molex are often used in applications
in which high signal speed, power distribution, heat, and space savings are issues.