ams Says New Sensor Can Monitor Blood-Oxygen Levels in Wearable Designs

September 23, 2020 by Jake Hertz

The ultra-thin sensor integrates a photodiode, filter, and signal processing to remotely monitor Sp02 levels.

Of all of the fields benefiting from the technology boom of the past 10 years, the medical industry may be at the top of the list. In particular, wearable health devices have come center stage, finding huge market share and bringing benefits to individuals' health.

Continuous ambulatory monitoring of human vital signs during daily life can improve user health. It has also afforded individuals more freedom, giving them the ability to be remotely monitored, instead of frequently checked in a doctor's office. 


Example of a wearable vital sign monitor

Example of a wearable vital sign monitor. Image used courtesy of HospiMedica


With the demand for continuous monitoring rising, many companies have been developing more discreet and functional devices to measure vital signs.


The New Blood-Oxygen Sensor

ams, an Austrian sensor company, has recently introduced the newest addition to the list of vital sign monitoring devices

The AS7038RB offers a combination of features, including small size and integrated functionality. The sensor is packaged with a footprint of 3.70 mm x 3.10 mm x 0.65 mm, making it an thin device that occupies a small area.

In this small form factor, the sensor integrates a large and sensitive photo-diode, four LED drivers, an analog front end, and a sequencer. The sensor comes preloaded with the software necessary for SpO2 and heart rate measurement. 

ams says the AS7038RB also features SpO2 measurement accuracies that very closely compete with accuracies of medical-grade pulse oximeters used in hospitals.

In the press release, Wim Renirie, VP and GM for ams' accessory and wearable solutions, explains, "The AS7038RB offers an additional diagnostic tool, enabling the creation of wearable and disposable equipment for monitoring blood oxygen saturation accurately and safely, without requiring the presence of a medical practitioner.”


Flexible Design Means Flexible Applications

Given its small form factor and its flexible implementation, this sensor can be used in a wide range of applications. 

The AS7038RB’s use of drivers for up to four external LEDs gives OEMs the flexibility to place the LEDs in the best position for the application. This means LED placement can be optimized for the different skin thicknesses and bone structure at the wrist, chest, forehead, finger, and other locations.

The sensor works with a high-sensitivity photodiode, which produces a high optical signal-to-noise ratio. With a high SNR, the sensor can be implemented in applications such as disposable chest patches, wristbands, and smartwatches.


Block diagram of the AS7038GB

Block diagram of the AS7038GB. Image used courtesy of ams


According to ams, the AS7038RB is also the industry’s thinnest dedicated sensor for blood oxygen saturation (SpO2) measurement. This small footprint also means that it is particularly suitable for applications in remote diagnostic equipment, such as disposable patches used for SpO2 and electrocardiogram (ECG) measurements in hospital emergency rooms. 


Continuous Biometric Monitoring

All things considered, this new sensor from ams looks to bring the capability to remotely monitor vital signs, like Sp02, to small consumer products such as earbuds, smartwatches, and wristbands. This news is particularly relevant right now with studies finding that low SpO2 can be an early symptom of COVID-19 in some at-risk patients. 

Renirie remarks, “The introduction of the AS7038RB marks another ams breakthrough in technology for remote diagnostics. ams is working actively with a range of partners to develop innovative solutions for the testing and diagnosis of COVID-19."