Sensitive sensors without the ghosts: Avnet HMIs for surgery are strong, safe and reliable

By Stefano Rosato | 27 June 2023
Capacitive sensors are great – highly reliable and have a wide range of functions. But in the medical world there are some very particular requirements around the service life of such sensitive sensor technologies.

For example, display and touch systems in medical applications must be much more robust:

  • Being able to operate them while wearing latex gloves is essential
  • They must not generate false touches during cleaning
  • If a conductive liquid (such as blood) splashes on the display, it still must function perfectly
  • High standards of electromagnetic compatibility (EMC) and Electromagnetic interference (EMI) must be met
HMI Displays

In particular, EMC requirements require that no ghost touches are generated in an irradiation of 28V/m in some frequency ranges. Of course, our new touch controller means this is no longer an issue and the big challenge is to avoid ghost touches in high frequency surgery devices.

To address this, we have designed a highly robust touch solution that passes all necessary EMI/EMC tests and will eventually even block ghost touches from any nearby high frequency surgery devices or their cables.

To achieve this and ensuring that all issues are now avoided in medical applications, we adapted the pattern of the X/Y layers in the touch and added new special filters in the algorithm for the frequency of the touch IC (based on the SIS 95xx family).

This level of touch optimization is currently unique to Avnet and sits within our ability to improve time to market for our customers, even with such an important category of custom displays and HMIs.

Indeed, such HMIs are responsible for truly enhancing the patient/clinician experience by offering a 3D touch visualization which can be quickly shared with the patient (see left for example). Equally, such solutions are timesaving for doctors, allowing them to see more patients.

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About Author

Stefano Rosato - Director, Technical Touch Technology at Avnet

Stefano Rosato is director of technical touch technology in the Display Solutions team at Avnet. Stefano helps customers solve touch challenges and supports customers through the whole design-in phase for touchscreen integration. With deep knowledge about PCAP technology, along with its design-in rules, tuning and pattern designs, Stefano is a leading expert in the touchscreen industry.Read More

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