Health Monitoring and Fitness Tracking

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Application - Health Monitoring - Single men

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

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 7051

BIOFY® Sensor SFH 7051

  • Black Package
  • Package dimensions: 4.7 x 2.5 x 0.9 mm³
  • Photo Diode Sensitive Area: 1.3 x 1.3 mm²
  • Emitter color: green (530 nm)
SFH 7051
BIOFY® Sensor SFH 7060

BIOFY® Sensor SFH 7060

  • Black Package
  • Package dimensions: 7.2 x 2.5 x 0.9 mm³
  • Active detection surface: 1.7 x 1.7 mm²
  • Emitter color: red (660 nm), green (530 nm), infrared (940 nm)
SFH 7060

Infrared Emitting Diode for health monitoring

General Features

  • Highly efficient 940nm LEDs with latest thinfilm technology
  • Narrow viewing angles
  • Short switching times
  • Package sizes suitable for consumer applications
  • Low profile components
MINI MIDLED SFH 4441

Mini MIDLED SFH 4441

  • Radiant Intensity @ max. DC current: 65 mW/sr
  • Total radiant flux@ max. DC current: 50mW
  • max. forward DC current: 100 mA
  • max. pulse current: 1 A
  • Viewing Angle: +/-17°
  • Package height in mm: 0.9
  • XY Dimensions in mm: 2.3 x 1.95
CHIPLED with lens SFH 4046

Chipled with lens SFH 4046

  • Radiant Intensity @ max. DC current: 30 mW/sr
  • Total radiant flux@ max. DC current: 40mW
  • max. forward DC current: 70 mA
  • max. pulse current: 700 mA
  • Viewing Angle: +/-22°
  • Package height in mm: 1.0
  • XY Dimensions in mm: 3.2 x 1.6

Green LED for health monitoring

CHIPLED 0402 • LT QH9G

ChipLED LT QH9G

  • Package: SMT package, colorless diffused resin
  • Package size: 1.0 x 0.5 x 0.4 mm3
  • Technology: InGaN
  • Viewing angle at 50 % IV: 155° (horizontal); 170° (vertical)
  • Color: true green (525 nm)
  • ESD - withstand voltage: ESD sensitive device acc. JESD22-A114-F ESD class 0
PointLED • LT P4SG

PointLED LT P4SG

  • 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

Photodiodes for health monitoring

SFH 2430

SFH 2430

  • Spectral sensitivity adapted to human eye sensitivity
  • Peak sensitivity at 570 nm
  • Big radiant sensitive area of 7.02 mm²
  • Low temperature coefficient of spectral sensitivity
  • High linearity
SFH 2440

SFH 2440

  • Spectral sensitivity 400-600 nm
  • Peak sensitivity at 620 nm
  • Big radiant sensitive area of 7.02 mm²
  • Low temperature coefficient of spectral sensitivity
  • High linearity
BPW 34 S

BPW 34 S

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

Health Monitoring and Fitness Tracking

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