MEMS microphones for hearing aids: a game changing technology

Faced with an aging “baby boomer” population, healthcare is more important than ever. In-vitro diagnostics, pharmaceutical research, patient monitoring, drug delivery, and implantable devices: all of these fields are growing. System integrators therefore need new and innovative technologies to rapidly improve performance, cost and size.

This is the case for MEMS microphones, which are still emerging components in the medical field. Traditional Electret Condenser Microphones (ECM) remain the most used microphones in hearing aids, but MEMS microphones are increasingly displacing them. In Yole Développement’s (Yole) recent report: “BioMEMS: Microsystems for Healthcare Applications”, Yole’s analysts explain how and why these MEMS devices will represent a $101M market in 2021, starting from $29M in 2015.

Penetration rate of MEMS microphones for hearing aids (Source: BioMEMS: Microsystems for Healthcare Applications)

In this context, Yole analysts were pleased to interview Mike Knapp, Vice President of Investor Relations at Knowles and Gordon Walker, the company’s President of Specialty Components – Acoustics and Hearing Health. Knowles recently announced that it has shipped its 10 millionth MEMS microphone for hearing aids. Read on to find out what Knapp and Walker had to say about that, their company’s activities, and MEMS microphones more generally.

Yole Développement (Yole): Could you briefly introduce Knowles and its history?
Knowles: Knowles was founded 70 years ago and has always aimed to develop and miniaturize high performance microphones, speakers and acoustic transducers. Headquartered in Chicago, Illinois, the company employs more than 12,000 people worldwide: in California, United Kingdom, Japan, Korea, Taiwan, and China, to mention just a few locations. Thanks to Knowles’ technology, hearing aid manufacturers have evolved from pocket aids to on-the-ear or behind-the-ear systems and are now even able to provide in-the-canal systems. Knowles started developing MEMS microphones in the late 1990s and sold its first devices in 2003. Since then, Knowles’ MEMS microphones have been integrated in many systems such as smartphones and mobile headsets.

Yole: Can you give an overview of your activities related to MEMS microphones for medical applications? When did you get involved in this market and why did you decide to address it?
Knowles: We had the opportunity to start shipping MEMS microphones for hearing aids in 2010, through a collaboration with one of the big players in this field positioning as an early adopter of MEMS technology. Today, our solution is used in more than 70 percent of hearing health MEMS-based products.

Yole: You started to ship MEMS microphones for hearing aids in 2010 and shipped your 2 millionth unit in July 2014. Less than two years later, at the beginning of April 2016, you announced the 10 millionth unit. How can you explain this impressive growth?
Knowles: We are still amazed by the fantastic growth of medical MEMS microphones. We really wanted to push those milestones and managed it well: today, many hearing aid manufacturers integrate MEMS microphones and the penetration rate is skyrocketing. The growth potential remains huge, with around 13 million hearing aids sold every year and a 3-4% annual growth on average.

MEMS microphone – Courtesy of Knowles

Yole: What are the main technical requirements? What are the synergies and the main differences in microphones used in medical and consumer applications, especially compared to mobile phones? 
Knowles: Both medical and consumer MEMS microphones are manufactured using similar technology processes. However, the dies and ASICs are quite different. The first difference is that the power is around 300 µA for consumer devices with 1.5V nominal voltage, versus 30 µA and 0.9V for medical microphones. Second, the size of the MEMS die differs. The die is larger for hearing aids because of the higher signal-to-noise ratio required whereas the ASIC has approximately the same size in both applications.

Yole: Can you explain why the average selling price for MEMS microphones is much higher for medical applications than in consumer?
Knowles: Indeed, there is an important difference in the price of consumer and medical MEMS microphones. This is mainly due to the difference in production volumes, which differ by two or three orders of magnitude. Although we recently shipped our 10 millionth MEMS microphone for hearing aids, it has to be placed in the context of our 8 billion MEMS microphones shipped in total. The differences at the ASIC level impact the cost as well. The average selling price for consumer applications is less than $0.5 and around $4 for hearing aids.

Yole: Your company has a strong position, leading the MEMS microphone market. What are your key advantages compared to your competitors?
Knowles: We would say that nobody has our scale or experience in MEMS microphone development, neither in low power ASIC development nor packaging for these devices.

Yole: MEMS microphones are increasingly replacing Electret Condenser Microphones (ECM) in hearing aids. What is the value MEMS adds?
Knowles: The advantages of MEMS microphones are multiple. First, they are much smaller than ECMs, which enables the miniaturization of the final system. Second, MEMS microphones perform much better. Even if they are functionally the same, they enable much higher stability with small deviation even under harsh environment conditions linked to extreme humidity or temperature. Moreover, MEMS microphones offer great reproducibility over time. After several years of use, the response will greatly differ among ECMs whereas it will remain the same among MEMS microphones. Last, but not least, the integration of ECMs is very difficult and costly whereas our MEMS microphones are surface-mounted and therefore much easier to integrate.

Yole: What’s the next step? Do you think MEMS technology will totally replace other microphone technologies in hearing aids?
Knowles: We hope they will! At the moment, ECMs are still cheaper than MEMS microphones. However, we expect their cost to converge in the next couple of years because of continued improvements made in the MEMS area, which will further increase the penetration rate of MEMS technology in related applications.

Yole: Do you see other medical devices which can benefit from using MEMS microphones?
Knowles: Of course, even though hearing aids are the biggest market at the moment we expect widespread adoption in other applications. Every time audio is key, MEMS microphones should be strongly considered.

Yole: Thank you very much for this discussion. To conclude, what can we wish you for 2016 and 2017?
Knowles: Well, we hope to enjoy continued growth thanks to MEMS microphones. In the context of ageing population, we continue to have strong research programs for medical MEMS applications in order to add intelligence, better user interface and capability to our components. We will pursue these aims and keep providing strong value!

 

 

Mike Knapp is the vice president of Communications & Investor Relations at Knowles. He has over 15 years of experience in investor relations and financial services, and extensive experience in executing communications and investor relations strategies for a broad range of technology-focused companies. Prior to Knowles, he served as the director of Investor Relations at Integrated Device Technology. He also worked as a Senior Associate for Thomson Financial in the Capital Markets Intelligence group, and as an Equity Derivatives Associate at Banc of America Securities, LLC.

Mike holds an M.B.A. in Finance from the University of Massachusetts, Lowell and a B.A. in Economics from the University of Colorado, Boulder.

 

Gordon Walker is president of Specialty Components—Acoustics and Hearing Health and oversees Knowles’ specialty acoustic components for the Hearing Health and Performance Audio markets. Through Gordon’s focus on close, cooperative relationships with customers and a performance-leading product portfolio, Knowles is the market leader in these core areas.

He has been with Knowles for 17 years and has held a variety of posts in product management and operations. Through his leadership, Gordon helped grow the Hearing Health component business by 50 percent. He also led the business development effort for Knowles in high-performance earphones, bringing the miniaturized high-fidelity hearing aid technology to consumer markets. His work in operations included experience in sourcing, ERP implementation, production transfers and operational restructuring.

Gordon serves on the board of the U.S.-based Hearing Industries Association (HIA) and also serves on the board of Chicago-based Horizons for Youth, an organization helping K-12 kids succeed through education. He graduated from Carleton College with a Bachelor of Arts degree in economics in 1997. He received his MBA from the University of Pennsylvania’s Wharton School in 2005.

 

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BioMEMS: Microsystems for Healthcare Applications 2016
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