Health Monitoring and Fitness Tracking

Application - Health Monitoring and Fitness Tracking - Runners in front of Mountain

Exactly what you need: high efficiency and great diversity

Along with the "Quantified Self Movement" gaining popularity, there is an increasing interest in medical measurement methods that can be integrated in so-called wearable gadgets such as watches, smart phones or fitness bracelets. It started with fitness trackers determining the step frequency by using acceleration sensors. Now optical sensors expand the possibilities of self-observation, as they also offer a straightforward measurement of the heart rate and oxygen saturation of the blood. In addition, the pulse measurement on the wrist or fingers is much more convenient than, say, wearing a chest strap. Last but not least optical methods score in economic terms as well, as the new technologies for highly efficient LEDs allow for more energy-efficient and compact sensors.

OSRAM Opto Semiconductors offers a great variety of innovative components for modern fitness tracking and health monitoring applications: green and red LEDs, photodiodes and infrared emitting diodes, in different packages, sizes and performance classes. All our sensor products are based on high-efficiency chip technology, ensuring low energy consumption and high signal quality for extremely reliable measurements at the same time. Simply choose the components you need for your special application.

Optical sensors for the measurement of the heart rate and the oxygen saturation of the blood make use of the light absorption in the blood, more specifically of the hemoglobin contained in the blood.

Heart rate monitoring

Light strikes the body tissue, and then is transmitted, absorbed and reflected (figure 1) – the larger the irradiated blood volume, the lower the amount of light reflected. As the blood volume in the arteries changes with the cardiac cycle, the heart rate results from the periodicity of the detector signal (figure 2). This optical measurement of the change of blood volume in the blood vessels is referred to as photoplethysmography (PPG). In practice, the sensor consisting of juxtaposed light source and detector is located directly on the skin, usually on the wrist or fingers. Due to the location the measurement is made at different wavelengths – green light has established itself as the best option for the wrist, red and infrared light for the finger.

Pulse oximetry

The oxygen saturation of the blood can be measured when infrared and red light are used at the same time (figure 3). This so-called pulse oximetry is based on the fact that hemoglobin (Hb) is changing its absorption behavior when it binds oxygen (oxyhemoglobin HbO2). The concentrations of these two variants of hemoglobin can be determined by measuring the absorption at two different wavelengths. This yields the oxygen saturation of the blood. Red (660 nm) and infrared (940 nm) light are the ideal choice, because here the absorption behavior of the two hemoglobin molecules deviates most from each other. In contrast to the pulse measurement, which is only considering the relative changes in light absorption, the light absorption of arterial blood must be measured in absolute terms here. In practice, the blood oxygen saturation can be expressed as a function of the ratio of the minimum and maximum detector signals (Imin/Imax) at the respective wavelength.

Optical measurement of biometric data

Figure 1

Optical measurement of biometric data
The sensor SFH 7050 is emitting green, red or infrared light, which irradiates skin or tissue and is absorbed or reflected. The amount of the reflected light registered by the detector varies with the amount of blood in the arteries (photoplethysmography). The measurement is carried out with green light on the wrist, with red or infrared wavelengths at the finger.

Measurement of the heart rate

Figure 2

Measurement of the heart rate
The periodicity of the detector signal I corresponds to the pulsation of the amount of blood in the arteries. The ratio of the minimum and maximum signal values (Imin/Imax) is relevant for the determination of the oxygen saturation of the blood (pulse oximetry).

Determination of the oxygen saturation of the blood

Figure 3

Determination of the oxygen saturation of the blood
The absorption behavior of blood – or more precisely of the blood pigment hemoglobin (Hb) – changes at oxygen uptake (oxyhemoglobin or HbO2). By measuring the absorption of red and infrared light, the oxygen saturation of the blood can be determined.

BIOFY® Sensor SFH 7050

  • Black Package
  • Package dimensions: 4.7 x 2.5 x 0.9 mm³
  • Active detection surface: 1.3 x 1.3 mm²
  • Emitter color: red (655 nm), green (530 nm), infrared (940 nm)
SFH 7050

BIOFY® Sensor SFH 7070

  • White Package
  • Package dimensions: 7.5 x 3.9 x 0.9 mm³
  • Integrated Light Barriers to block optical crosstalk
  • Emitter color: two green (530 nm)
  • Optimized for strong PPG signal
SFH 7070

BIOFY® Sensor SFH 7072

  • White Package
  • Package dimensions: 7.5 x 3.9 x 0.9 mm³
  • Integrated Light Barriers to block optical crosstalk
  • Emitter color: red (655 nm), green (530 nm), infrared (940 nm)
  • Two photodiodes: One broad band, one with IR cut filter
  • Optimized for strong PPG signal

G/R/IR Triple color CHIPLED®

CHIPLED® SFH 7013

  • Compact Chipled Package
  • Package dimensions: 2.5 x 1.6 x 0.55 mm³
  • Active detection surface: 1.3 x 1.3 mm²
  • Emitter color: red (655 nm), green (530 nm) and IR emitter (940 nm)
  • Emitters can be controlled seperately
  • Optimized for strong green brightness
CHIPLED® SFH 7013

PIN photodiodes

NEW

TOPLED® SFH 2201

Features:

  • Suitable for reflow soldering
  • small package: (WxDxH) 4 mm x 5.1 mm x 0.85mm
  • Solder control structure

Applications:

  • Photointerrupters
  • Industrial electronics
  • For control and drive circuits
TOPLED® SFH 2201

BPW 34 S

  • Wide spectral sensitivity from 400 nm to 1100 nm
  • Peak sensitivity at 850 nm
  • Big radiant sensitive area of 7.02 mm²
  • Low temperature coefficient of spectral sensitivity
BPW 34 S

DIL SMT Ambient Light Sensor SFH 2440

  • Spectral sensitivity 400 – 690 nm
  • Peak sensitivity at 620 nm
  • Big radiant sensitive area of 7.02 mm²
  • Low temperature coefficient of spectral sensitivity
  • High linearity
DIL SMT Ambient Light Sensor SFH 2440

TOPLED® D5140 SFH 2200

  • Compact QFN package: 5.1 x 4.0 x 0.85 mm³
  • Spectral sensitivity 300-1100 nm
  • Peak sensitivity at 940 nm
  • Big radiant sensitive area of 7.02 mm²
  • Low temperature coefficient of spectral sensitivity
  • High linearity
TOPLED® D5140 SFH 2200

Single color LEDs

CHIPLED® SFH 4043

  • Very small package: 1.0 x 0.5 x 0.45 mm³
  • Emitting wavelength: 940 nm
  • Light emitting area: 0.2 x 0.2 mm²
  • For SpO2 measurement and proximity detection
CHIPLED® SFH 4043

PointLED® Green LT PWSG

  • Package: white SMT package, colorless clear silicone resin
  • Package size: 3.4 x 1.3 x 0.8 mm³
  • Technology: ThinGaN
  • Viewing angle at 50 % IV: 120° (horizontal); 120° (vertical)
  • Color: true green (528 nm)
  • Available in Top Mount or Reverse Mount options for through hole applications
PointLED® Green LT PWSG

FIREFLY® Green CT DELSS1.12

  • Package: white SMT package, colorless clear silicone resin
  • Package size: 1.6 x 0.8 x 0.6 mm³
  • Technology: ThinGaN
  • Viewing angle at 50 % IV: 120° (horizontal); 120° (vertical)
  • Color: true green (530 nm)
FIREFLY® Green CT DELSS1.12

FIREFLY® Red CH DELSS 1.22

  • Package: white SMT package, colorless clear silicone resin
  • Package size: 1.6 x 0.8 x 0.6 mm³
  • Technology: ThinGaN
  • Viewing angle at 50 % IV: 120° (horizontal); 120° (vertical)
  • Color: hyper red (657 nm)
FIREFLY® Red CH DELSS 1.22
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Health Monitoring and Fitness Tracking

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