■ Medical Devices Also Generate Heat
Medical devices also contain various heat sources.
● Power supply circuits
● Sensors
● Motors
● LEDs
● Lasers
● Communication modules
● Computing chips
● Batteries
● Image processing units
When these operate, they consume power.
And much of the power consumed turns into heat.
In other words, medical devices basically cannot escape the law of physics that using electricity generates heat.
■ In Medical Devices, the Distance to the Human Body Is Short
The reason heat problems in medical devices are difficult is that they are close to the human body.
For example, in devices that are
● Attached to the skin
● Worn on the body
● Held in the hand
● Brought close to the affected area
● Used close to the inside of the body
heat generation leads directly to effects on the human body.
In other words, in medical devices, a temperature at which the device does not break is not enough.
It must be a temperature that is safe for people.
■ "A Little Hot" Becomes a Problem
In general industrial equipment, getting somewhat hot may be acceptable as long as the equipment does not break.
In medical devices, however, things are different.
Patients feel uncomfortable.
It puts a burden on the skin.
Long-term use creates a risk of low-temperature burns.
It affects measured values.
It worsens operability for medical professionals.
In other words, in medical devices, “a little hot” can become a major problem.
■ The Risk of Low-Temperature Burns
In medical devices, attention to low-temperature burns is important.
A low-temperature burn is a phenomenon in which deep layers of the skin are damaged by prolonged contact even at temperatures that are not particularly high.
Particular care is needed with
● Devices attached to the skin
● Sensors worn for long periods
● Devices for the elderly
● Home medical devices
● Wearable medical devices
In other words, in medical devices, not only how many degrees it rises to,
but also for how long and where it touches matters.
■ Heat Also Affects Measurement Accuracy
In medical devices, heat can also affect measurement accuracy.
For example, in
● Temperature sensors
● Pressure sensors
● Optical sensors
● Biosignal sensors
● Diagnostic imaging equipment
sensor output may change due to changes in component temperature.
In other words, heat problems relate not only to safety,
but also to measurement accuracy.
■ Miniaturization Worsens Heat Problems
Medical devices will also become even smaller in the future.
As home medical care and telemedicine spread beyond hospitals,
● Small size
● Light weight
● Long operating time
● Wireless
● Skin contact
● Continuous measurement
will be required.
However, miniaturization reduces the space for releasing heat.
In other words, the more medical devices move toward being small yet highly functional, the more difficult heat problems become.
■ In Home Medical Care, the Users Are Not Experts
In the future of medical devices, the importance of home medical care will increase.
In hospitals, experts manage the equipment.
In home medical care, however,
there will be more situations in which patients themselves or their families use the devices.
Then
● Misuse
● Long-term wear
● Ways of use that block heat dissipation
● Dirt
● Humidity
● Individual differences in skin condition
will occur.
In other words, home medical devices need thermal design that even takes into account that the on-site environment varies.
■ Medical Devices Also Battle for Cleanliness
In medical devices, cleanliness and ease of disinfection are also important.
However, structures that are easy to keep clean, highly waterproof, and highly sealed can make it harder to release heat.
In other words, in medical devices, wanting to keep it clean and
wanting to release heat can clash.
■ The Contradiction Between Waterproofing/Dustproofing and Heat Dissipation
In medical settings, resistance to moisture, chemical solutions, sweat, disinfectants, and so on is required.
That is why waterproof and dustproof design is needed.
However, sealing reduces airflow.
Then heat tends to build up.
In other words, in medical devices, safety, cleanliness, and waterproofing
and heat dissipation must be achieved at the same time.
This is what is difficult.
■ Medical Devices Also Need Softness
In medical devices that touch the human body, components that are too hard lead to discomfort and pain.
That is why they are required to be
● Soft
● Thin
● Light
● Able to conform to curved surfaces
However, soft materials and foam materials can generally make it harder to release heat.
In other words, in medical devices, wanting to make it soft and wanting to release heat also clash.
■ Medical Devices Are a Combined Problem of Heat × Safety × Comfort
Heat problems in medical devices are not simple heat dissipation problems.
In reality,
● Heat
● Safety
● Comfort
● Cleanliness
● Waterproofing
● Flexibility
● Measurement accuracy
● Long-term use
● Volume production stability
are all intertwined at the same time.
In other words, thermal management for medical devices does not work if you look only at heat.
■ AI Medical Devices Will Increase Heat Problems Further
From now on, AI will also be built into medical devices.
For example,
● Diagnostic imaging support
● Biodata analysis
● Anomaly detection
● Remote monitoring
● AI medical interviews
● Surgical support
As AI processing increases, the amount of computation increases.
As the amount of computation increases, heat generation also increases.
In other words, future medical devices may face even more difficult heat problems due to miniaturization and AI integration.
■ The Researcher's Perspective: Medical Devices Need Thermal Design That Coexists with the Human Body
In research and development,
● Low-power design
● Flexible heat dissipation materials
● Thin heat spreading sheets
● Skin temperature management
● Biocompatible materials
● Balancing heat dissipation and waterproofing
● Temperature control by AI, and so on become important.
In medical devices, it is required not just to cool, but to control heat within a range that is safe for the human body.
■ The Shop-Floor Perspective: Even If It Is Safe in Theory, It Changes with How It Is Used
In medical devices, even if a device is safe by design, problems can occur in the actual usage environment.
For example,
● Being left attached for long periods
● The state of contact with the skin
● Sweat and humidity
● Heat dissipation blocked by clothing or bedding
● Skin sensitivity of the elderly and children
● Differences in how each user wears it
In other words, in thermal management for medical devices, not only the theoretical temperature,
but also how it is actually used must be considered.
■ Thermal Performance Changes with Contact and Lamination
In medical devices, thin heat dissipation materials, insulating materials, adhesive materials, cushioning materials, and so on may be used.
However, if there is
● Uneven adhesive thickness
● Air bubbles
● Lifting
● Insufficient conformity to curved surfaces
● Peeling
● Material deformation
the way heat escapes changes.
In other words, in medical devices too, choosing materials alone is not enough.
How to bring them into contact with the human body and components is important.
■ OTIS's Perspective
From OTIS’s perspective, what matters in heat problems for medical devices is
● Thin-film processing
● High-precision die-cutting
● Flexible material processing
● Adhesive material processing
● Insulating material processing
● High-precision lamination
● Processing of components that conform to curved surfaces
● Volume production stability of small components
● Supply formats that take cleanliness into account
In medical devices, components are small, thin, and close to the human body.
That is precisely why
processing accuracy, lamination accuracy, and volume production stability are important.
■ What OTIS Can Do
At OTIS, through
● Tape and film processing for medical applications
● Thin-film component processing
● Insulating sheet processing
● Heat dissipation sheet processing
● Adhesive material processing
● High-precision die-cutting
● High-precision lamination
● Reel supply of small components
● Designing supply formats for automated processes
and more, we may be able to contribute to making functional components for medical devices work in volume production.
In devices close to the human body in particular, it is important that they can be applied thinly, lightly, softly, and stably.
■ Outside OTIS's Expertise
On the other hand, OTIS is not a company that specializes in
● Medical device body design
● Medical diagnostic algorithm development
● Biological analysis
● Acting on behalf of clients to obtain medical certifications
● Electronic circuit design
However, in the area of making functional components used inside medical devices and close to the human body work in volume production processes, we may be able to play an important role.
■ Industries Where This Technology Will Be Important
★★★★★ Medical devices
★★★★★ Home medical devices
★★★★★ Wearable medical devices
★★★★☆ Biosensors
★★★★☆ Telemedicine devices
★★★★☆ AI diagnostic support devices
■ Summary
Heat problems in medical devices are not simply a matter of component temperature.
They are close to the human body.
They are used for long periods.
They affect measurement accuracy.
They also relate to safety and comfort.
That is why, in medical devices, just being able to cool it is not enough.
Safe for the human body, comfortable, clean, and stable even in volume production.
Only when all of that works does it become true thermal management.
And from now on, the more medical devices become smaller, AI-enabled, and home-based, the more important heat problems will become.
Column Supervisor: Koji Kakumoto (President, OTIS Co., Ltd.)
After studying abroad and working in planning and development at a trading company, he joined OTIS Co., Ltd. in 2011. While primarily working in the Corporate Planning Department, he has also served concurrently in manufacturing and technical divisions, and since 2018 has served as President, working to drive business growth and strengthen the organization.
This article is a general technical explanation intended for educational purposes and does not refer to any specific company, product, or technology.
