Optoelectronic

Optoelectronic components can be divided into actuators (emitters) and detectors (receivers):

• Optoelectronic actuators generate light from electricity, e. g. lasers and light-emitting diodes – in both the visible and the invisible spectral range (UV or infrared).
• Optoelectronic detectors are their counterparts, e. g. photoresistors, photodiodes and phototransistors as well as light sensors such as CCD sensors.

A further distinction is made between active and passive components:

• Active components emit radiation – e. g. LED lights, UV emitters and laser diodes.
• Passive components process light but do not generate radiation – e. g. infrared receivers, phototransistors and photodiodes.

Optoelectronic sensors use light as a measured variable to gather information about their environment. They consist of an actuator that emits light and a detector that detects and measures it. When both are operated as a system, the result is an optical sensor – also known as an optosensor.

They are used, among other things, in industrial automation, medical technology, transport technology and consumer electronics – for measuring distances, speeds, tilt angles and accelerations. Typical designs are:

• Fibre-optic sensors – guide light through glass fibres for data transmission or distance measurement.
• Photodiode sensors – measure illuminance levels or detect movement.

Materials play a central role in components that act as an interface between electrical and optical elements. The decisive factor is their ability to emit or detect light – which is why semiconductor materials are usually used.

Popular materials include, for example:

• Semiconductors such as silicon and gallium arsenide
• Glass fibres for optical data transmission
• Polymer materials for flexible electronic devices
• Quartz for optical components and semiconductor lasers
• Sapphire for optical components and LED housings
• Germanium and zinc selenide for infrared detectors
• Aluminium oxide and barium sulfide for optical components
• Indium phosphide for optical components and waveguides

The choice depends on the desired property (e. g. emission spectrum or detection sensitivity), the application and the manufacturing method.

Optoelectronics is used in many areas:

• Optical communication & data transmission – transmitting information over long distances, e. g. in fibre-optic cables, laser printers and projectors.
• Optical sensors & measuring systems – measuring physical quantities such as temperature, pressure, humidity and motion in industry, medical technology and environmental monitoring.
• Optical storage & data storage – recording and playing back digital data, e. g. in CD, DVD and Blu-ray players.
• Optical image processing & image sensors – generating and processing images in cameras, smartphones and drones.
• Display technology & lighting – image generation and illumination in monitors, televisions, projectors and LED lamps.