Osram Opto Semiconductors SFH 7050 integrated optical sensor

SFH 7050 is an integrated optical sensor for automatic fitness tracking. The sensor is used in mobile devices, such as smart watches and fitness armbands, and simplifies personal heart rate or pulse rate measurements.

The sensor contains three light-emitting diodes with different wavelengths, based on highly efficient chip technology. This helps save power and also offers high signal quality for reliable measurements. A built-in photodetector receives the reflected optical signals and is separated from the emitters by an opaque barrier.

The photodiode integrated in the sensor (4.7 x 2.5 x 0.9 mm) has an active surface of 1.3 x 1.3 mm. The diode is therefore very sensitive to light and has high linearity and good signal-to-noise ratio. The infrared LED can also be used in combination with the photodiode as a proximity sensor to start or stop the measurement automatically as soon as the sensor touches or is removed from the skin. The integrated optical barrier prevents crosstalk from the three LEDs to the photodiode and therefore corruption of the optical signal or the entire measurement.