Combining electrical and mechanical components to produce a system of unprecedented miniature dimensions, MEMS have emerged as an important technology of choice for the design of small, portable devices in a range of dynamic healthcare markets.
Skyrocketing global healthcare costs, compounded by aging populations, are driving a surge in demand for portable medical diagnostic equipment and treatment in patients’ homes as well as in underserved and remote regions. A recent industry report1 cites the proliferation of new equipment and markets serving patient home healthcare needs, including respiratory therapy, home infusion therapy, rehabilitation services, and monitoring of patients with chronic medical conditions (Fig. 1).
1. Patient monitors are evolving from hospital bedside equipment to home healthcare and internetworked systems. Micro-interconnect I/O solutions and innovative capabilities align with the trend toward smaller, lighter, and integrated solutions for telehealth applications.
In addition to projecting the home healthcare market to grow at an annual rate of 7.7% through 2016, the report notes that the most significant trend is the shift of treatment from hospitals to home to gain a cost advantage and reduce hospital expenditure. The move from treatment to proactive monitoring is opening up opportunities for the home healthcare market as well, the report adds, as patients prefer home healthcare to hospitals for the convenience and cost-effectiveness it offers.
As healthcare providers and patients navigate these transitions, leading electronics innovators are facing the technological challenges when equipment and devices traditionally used in doctor offices, clinics, and hospital settings move into patient homes. Among those challenges, power management plays a vital role in terms of the ease of patient use, size, performance, and durability of these devices. So, engineers weighing system-level tradeoffs must make power management decisions as early as possible in the design cycle.
The power connector industry has stepped up with extremely small, low-profile connectors, pioneered in the smart-phone industry, to meet this growing need for improved portability and miniaturization in medical devices and equipment. Combining electrical and mechanical components to produce a system of unprecedented miniature dimensions, microelectromechanical systems (MEMS) have emerged as an important technology of choice for the design of small, portable devices in a range of dynamic healthcare markets.
MEMS technology can be used in biomedical applications such as surgical tools, drug delivery, and biosensors, as well as in diagnostic and other in vitro applications. A compatible replacement for other larger connectors in existing designs, MEMS technology offers an ultra-low-profile solution and high performance in power connections. With a successful track record of real-world applications and customers, the MEMS micro-interconnect approach offers a powerful and viable tool for design engineers addressing demand for ever smaller micro-products to serve healthcare needs.
The Benefits Of MEMS
MEMS I/O connectors are suitable for any market in which miniaturization plays a major role, including consumer, mobile, and medical applications. The technology has already made remarkable contributions to medicine in its efforts to improve patient care and safety, specifically during minimally invasive surgery, and for patients requiring frequent blood and urine testing and monitoring, as well as those receiving medications via sensored patches.
There are myriad benefits to using MEMS I/O technology in medical devices and equipment. Providing a reliable and flexible socketed interface, MEMS I/Os are more robust than many conventional connectors. Their “zero height” makes them ideal for drug delivery patches that electronically control precision dosing at set intervals. Consuming little power, they also improve the consistency of readings and require fewer battery changes in portable monitoring or other devices. In invasive procedures, MEMS I/Os can enable a smaller device footprint for a less painful experience for the patient as well.
MEMS I/O connectors have proven particularly innovative in medical battery connectors, camera modules, and sheet connector I/O applications, such as those found in sensors for small form factor, high-density ultrasound connectors (Fig. 2). Ultrasound technology is an area of considerable patient need and a strong focus for leading health equipment manufacturers. Size and other limitations make current ultrasound machines impractical for use in many regions of the world. Developing and emerging countries benefit with the influx of more MEMS-based micro-products, enabling a smaller, portable ultrasound footprint for use in remote regions.
2. MEMS I/O connectors have proven particularly innovative in medical battery connectors, camera modules, and sheet connector I/O applications, such as those found in sensors for small form factor, high-density ultrasound connectors.
The medical sensor market offers enormous application potential for MEMS, including refresher sensors, chemical sensors, flow sensors, and position sensors. Today, nearly 70% of chemical sensors in the U.S. market are oriented to healthcare. With the epidemic of obesity and incidence of diabetes on the rise, the low-profile format MEMS power connector is ideal for the mobile and portable glucose monitoring market. In home and institutional healthcare, any device or equipment problem can potentially place a patient at risk. Offering a stable, socketed “pull & lock” connection, MEMS I/O technology is ideal for handheld patient glucose and other disposable monitoring products.
A portable glucose monitoring device using a standard micro I/O to connect two boards results in a profile of approximately 0.7 mm. With MEMS technology, the same connector profile can be reduced to a mere 0.15 mm. An unprecedentedly miniscule layer, a MEMS connection appears visually as a flat surface, not unlike the depth of a diabetic strip. These power-packed miniature solutions meet healthcare demands and place reliable monitoring tools into patients’ hands.
For high-impedance controlled cable solutions, MEMS I/O technology helps to mitigate these risks and can be used in conjunction with high-speed copper flex or any flexible substrate. Some medical manufacturers use copper flex with tiny connections for actual monitoring. If a manufacturer is not using MEMS, it typically solders the jumper via anisotropic conductive film (ACF) bonding directly to the copper flex. Initially used in mobile phones but applicable for medical devices, micro-camera modules are often directly soldered and permanently mounted on a jumper to the flexible cable printed-circuit board (PCB). Using this design concept, copper flex can become a costly jumper if the camera module is damaged and requires repair. More often than not, the “fix” is to disconnect and replace the entire flex cable.
However, MEMS I/O technology enables a micro-camera to be socketed directly onto the flex, without resulting in a higher profile, allowing easy disconnection and servicing without total replacement of the flex. In conjunction with a video-enabled camera or micro insulation displacement termination (IDT), a MEMS I/O can also be used to connect an HD video display to the main circuit board for streaming high-speed video in endoscopic and other invasive medical procedures. Conventional endoscopes for diagnosing gastrointestinal colon cancer and other anomalies require patient sedation and enable viewing of only a portion of the small intestine. A MEMS-enabled endoscope allows a complete examination of the small intestine in a sedation-free procedure that enables digital images, a transmitter, and even a light source.
MEMS Manufacturing Advantages
A natural progression of the same processes used in semiconductor fabrication, MEMS fabrication entails the deposition of material layers onto which photolithography and etching produce the required circuitry and components such as power connectors. Standard power connectors designed for medical devices generally comprise molded plastic with stamped terminals and contacts, which produces a relatively large footprint overall.
Conversely, the technology behind MEMS basically comprises masking, catching, plating, printing, and laminating, producing a very low-profile contact sheet. A MEMS I/O system typically employs etching and drilling on extremely thin layers of sheet metal to create a sandwich-like insulated electrical connection. Sheets may be as thin as 150 µm (0.15 mm). The advantage to MEMS is that the manufacturer can produce a significantly smaller, low-power consumption connector that delivers higher performance than larger competitive components. Additionally, the MEMS manufacturing process reduces time-to-market and the cost of producing a plastic injected mold and dye stamping terminals as are found in traditional connectors.
MEMS I/O technology integrates the high density and high-speed functionalities of high-speed connectors and cabling in micro-miniature products in a smaller form factor sheet connector that eliminates electromagnetic interference (EMI). MEMS I/O connectors are rated for the same number of mating cycles as standard micro-miniature connectors, which typically rate at 15 to 30 mating-unmating cycles, but some models can range well into the thousands. Stringent testing shows that the MEMS I/O mating interface can withstand dropping and shock up to 6000 G with negligible impact.
By eliminating most of the traditional connector body without sacrificing performance or density, MEMS I/O technology represents an important paradigm shift for medical device designers and manufacturers. Not only does it drive down size and valuable space on the PCB, but by replacing permanent soldered PCB connections with a simple socketed mating interface, it also enables a level of design flexibility that heretofore could only be found in larger connectors and product designs. Not surprisingly, the use of MEMS-enabled systems in medical equipment and devices has grown exponentially and is likely to continue this rapid growth trajectory.
1. Home Healthcare Market Current Trends, Opportunities & Global Forecasts to 2016; www.marketsandmarkets.com/Market-Reports/home-healthcare-equipment-marke...
Joe Falcone is the group product manager with the Lisle Satellite team in Molex’s Global Micro Products Division. He has 15 years experience in the interconnect industry in various sales, marketing, global business development, and product management roles. He holds a BSEE in electrical engineering and an MBA in finance/marketing. He can be reached at firstname.lastname@example.org.
Anthony J. Kalaijakis is the strategic medical marketing manager for Molex Inc. He has more than two decades of experience in the interconnect industry in various engineering, marketing, and sales positions. He can be reached at email@example.com.