The Future of Medical Technology - Part 6: Optical Sensors

Aug 24, 2017

What are Optical Sensors?

Optical sensors are devices used to safely measure biological, chemical and physiological parameters of the body. These sensors provide quantitative, qualitative and reliable results. They are life-saving devices that can simply acquire and process physiological information. Biomedical sensors are in high demand because they’re small, smart, reliable, selective, sensitive, biocompatible, fast, easy to manufacture in bulk and remotely controllable. They have the unique ability to select one parameter without interfering with other parameters. Types of biomedical sensors include, direct/indirect, contact/remote, invasive/noninvasive, real-time/static and sense/actuate. Each biomedical sensor consists of a sensing element with a physical transducer that converts a measure and into an output signal.

Applications of Optical Sensors

Optical sensors are used in health monitors, brain function monitors and wearables. Glucose meters are embedded optical sensors which can measure blood sugar levels with a camera-like device. This well-lauded device requires no finger pricking to measure glucose levels.

Optical Sensors in Symmetry’s Line Up

The Si1120 from Silicon Labs is a high-sensitivity active infrared proximity and ambient light sensor IC, enabling innovative touchless human interface applications with ultra-low power advantages. Consisting of an infrared LED driver, an infrared photodiode, an ambient light sensor and control logic, the device is packaged in a 3 mm x 3 mm clear DFN. The high-sensitivity infrared proximity measurement, offering customers an opportunity to implement a proximity and ambient light sensor with very lower power levels.


PWM output
Ambient Light Sensor
Seven Precision Optical measurement modes
3 proximity ranges
3 DC ambient light sensing ranges
1 calibration mode
Low-noise ambient cancelling circuit allows maximum sensitive with 8-12 bit resolution
Working in direct sunlight (100 klux)
Minimum reflectance sensitivity < 1 µW/cm2
High EMI immunity without shielded packaging
Power Supply: 2.2-3.7 V
Operating temperature range -40 to +85 degrees C
Typical 10 µA current consumption
Programmable 400/50 mA LED constant current driver output
Allows independent LED supply voltage


These low cost high precision optical displacement sensors are designed to detect displacements of objects. Original optical design technology and circuit and machine technology provides high precision along with an extended range.

High accuracy => Measurement accuracy +/- 0.1
Long range => Range of detection: 1000 µm
Compact size => 20x20x10mm


Read other blogs in this series:

The Future of Medical Technology - Part 5: Wi-Fi

The Future of Medical Technology – Part 4: Bluetooth Low Energy

The Future of Medical Technology - Part 3: Biometric Sensors

The Future of Medical Technology - Part 2: Wireless Video & Audio

The Future of Medical Technology - Part 1


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