Fast and ultrasensitive optical systems are gaining increasing significance and are being used in a diverse range of applications, for example, in imaging procedures in the fields of medicine and biology, in astronomy and in safety engineering for the automotive industry.
Frequently the challenge lies in being able to record high-quality images under extremely low light conditions. Modern photo detectors for image capture typically reach their limits here. They frequently work with light-sensitive electronic components that are based on CMOS (Complementary Metal Oxide Semiconductor) or CCD (Charge-Coupled Device) image sensors.
The problem is that neither the latest CMOS nor CCD systems can simultaneously guarantee a swift and highly-sensitive high quality image recording if there is a paucity of photons to read.
In cooperation with the partners of the MiSPiA project consortium the Fraunhofer Institute for Microelectronic Circuits and Systems IMS in Duisburg has now advanced the development of CMOS technology and introduced an ultrasensitive image sensor with this technology, based on Single Photon Avalanche Photodiodes (SPAD).
Its pixel structure can count individual photons within a few picoseconds, and is therefore a thousand times faster than comparable models. Since each individual photon is taken into consideration camera images are also possible with extremely weak light sources.
Camera installed directly on chip
To achieve this the new image sensor uses the “internal avalanche breakdown effect”– a photoelectric amplification effect. The number of “avalanche breakdowns” corresponds to the number of photons that the pixels hit. In order to count these events, each of the sensor’s pixels comes with very precise digital counters. At the same time, the scientists have applied microlenses to each sensor chip, which focus the incoming beam in each pixel onto the photoactive surface. Another advantage is that processing the digital image signals is already possible directly on the microchip; therefore, additional analogue signal processing is no longer needed.
“The image sensor is a major step toward digital image generation and image processing. It allows us to have the capability to use even very weak light sources for photography. The new technology installs the camera directly on the semiconductor, and is capable of turning the information from the light into images at a significantly faster pace,” states Dr. Daniel Durini, group manager for optical components at the Fraunhofer Institute IMS.
IMS engineered the sensor under the European research project MiSPiA (Microelectronic Single-Photon 3D Imaging Arrays for low-light high-speed Safety and Security Applications). Altogether, seven partners throughout Europe from the fields of research and business are involved in the project. In the next stage, the scientists from Duisburg are working on a process to produce sensors that are back-lighted, and in this regard, even more powerful. At the same time, the new technology is already being utilized in tests for traffic. Chip-based mini-cameras protect vehicles, bicycles and pedestrians from collisions and chip-based accidents, or assist in the reliable functioning of safety belts and airbags.
The Fraunhofer Institute IMS will exhibit the new image sensor at “Vision” – the world’s leading trade show for image processing – from November 6 to 8, 2012 in Stuttgart at stand H74 in Hall 1.
Dr.-Ing. Daniel Durini | Source: EurekAlert!
More articles from Power and Electrical Engineering:
Harvesting Electricity: Triboelectric Generators Capture Wasted Power
10.12.2013 | Georgia Institute of Technology
Scientists discover quick recipe for producing hydrogen
09.12.2013 | Deep Carbon Observatory
The molecular architecture of three key proteins and their complexes reveals how plants fine-tune their immune response to pathogens
Plants rarely get sick in their natural environment. When the threat of infection arises, a quick decision is made about the necessary countermeasures. The course is set by a protein which forms complexes with its partner proteins for this purpose.
Jane Parker from the Max Planck Institute for Plant Breeding ...
Researchers studying speciation of butterfly orchids on the Azores have been startled to discover that the answer to a long-debated question "Do the islands support one species or two species?" is actually "three species".
Hochstetter's Butterfly-orchid, newly recognized following application of a battery of scientific techniques and reveling in a complex taxonomic history worthy of Sherlock Holmes, is arguably Europe's rarest orchid species. Under threat in its mountain-top retreat, the orchid urgently requires conservation recognition.
A lavishly illustrated publication, titled "Systematic revision of Platanthera in ...
Researchers from Brown University and the University of Hawaii have found some mineralogical surprises in the Moon's largest impact crater.
Data from the Moon Mineralogy Mapper that flew aboard India's Chandrayaan-1 lunar orbiter shows a diverse mineralogy in the subsurface of the giant South Pole Aitken basin.
The differing mineral signatures could be reflective of the minerals dredged up at the time of the giant impact 4 billion years ago, ...
In power electronics systems bonded connections create the central electrical connections between adjoining surfaces.
The quality of these bonded connections is one of the main factors that determines the reliability and availability of drive systems in electric vehicles, and hence constitutes a major design challenge for German auto manufacturers aiming to electrify their vehicles.
Now the partners participating in the RoBE (Robust Bonds in ...
International team of scientists develops new feedback method for optimizing the laser pulse shapes used in the control of chemical reactions
In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Like an accomplished chef, chemists have become very skilled ...
11.12.2013 | Information Technology
11.12.2013 | Life Sciences
11.12.2013 | Agricultural and Forestry Science
11.12.2013 | Event News
10.12.2013 | Event News
05.12.2013 | Event News