Driver-support equipments such as radar sensors, infrared detectors and fatigue sensors capable of identifying risks, assisting drivers in critical situations and reducing driving related risks and traffic fatalities are currently available only for highly priced vehicles due to their expensive components.
To make the sensitive systems available to small and medium-sized cars as well, researchers at the Berlin-based Fraunhofer Institute for Reliability and Microintegration have collaborated with chip manufacturer STMicroelectronics and Centro Ricerche Fiat to design and produce a sensor system in a cost-effective manner. This project to develop sensors capable of differentiating between darkness and fog is being sponsored by the European Union and is titled ADOSE.
The group manager of the Fraunhofer Institute, Dr Henning Schroeder explained that darkness and fog display optically identical spectra which makes it difficult for sensors to differentiate between the two. To overcome the issue, the multifunctional system being developed by the researchers features two sensors fitted with Fresnel lenses which identify light signals, a camera and an infrared LED which emits light waves which do not scatter back in darkness, as they do in conditions of fog.
The researchers have also developed lightpipes to modify optical signal transmission. Dr Schroeder stated that the task of capturing light signals from the broad aperture angle, gathering it and passing it to the corners of the chip is a pain staking process, especially since the centre of the chip is designed for recording the image from the camera. Developed in a hot stamping process, the lightpipes which are hollow, mirrored tubes are capable of deflecting a signal of light by about 90°. This technique makes the optical signal transmission a more efficient process and makes the system compact, thus reducing production costs. Additionally, the system developed by the researchers can be expanded by adding additional lightpipes.
The Fraunhofer researchers have also designed a prototype of the sensor module using rapid prototyping. An initial field test will be set up by Centro Ricerche Fiat to test the multifunctional sensor system.
Source: http://www.fraunhofer.de/