New photodiode for precise health monitoring
21.02.2018 | Spotlight
Thanks to the emergence of fitness trackers and similar applications in recent years it is now easier than ever before to monitor your own health. Smart bracelets and watches measure your pulse, count the number of steps you take and show how many calories you have burned. All this is made possible by various sensors, such as optical sensors that measure heart rate and oxygen saturation by the amount of light absorbed by the blood pulsing at your wrist. The light emitted from the wearable device hits tissue and blood which absorbs some of the light and reflects the rest. Fitness trackers usually come with LEDs and photo diodes operating at multiple wavelengths. While green light is needed to measure the heart rate, red and infrared are used for monitoring the athlete’s blood oxygen level.
Future models will be capable of much more and, more importantly, their measurements will be more accurate. Osram Opto Semiconductors is the major contributor to the next generation of wearables for vital sign monitoring. For example, the company produces innovative photodiodes such as the new SFH 2201 which will improve the accuracy of measurements for such applications.
With its 36% higher green sensitivity compared to the SFH 2200, the new SFH 2201 sets a benchmark for all solutions currently available on the market. This high sensitivity plays a particularly important role in obtaining accurate results for vital sign monitoring, such as pulse rate, blood pressure measurement. In addition, blue sensitivity is increased by 59%. This makes SFH 2201 also as ideal for industrial applications such as smoke detectors, particle counters and bank note scanners.
SFH 2201 is designed to have a low capacitance and fast switching time. This is the key for the application to save energy and to increase measurement accuracy by operating at higher sampling rates. With dimensions of 4.0 mm x 5.1 mm x 0.85 mm, SFH 2201 has the same compact footprint as SFH 2200 so they are interchangeable.
SFH 2201 is surface mountable, has a large light-sensitive area of 2.85 mm x 2.85 mm and can be used for the wavelength range from 300 nm to 1,100 nm.
Further information is available here.Product Page TOPLED® SFH 2201 Datasheet TOPLED®, SFH 2201