Surface acoustic waves are ultrasonic waves propagating along the surface of a substrate. They are already used in a variety of sensing applications, for example in non destructive material testing.
ISAT uses a laser acoustic method to generate surface acoustic waves on a specimen without damaging its surface. A short laser pulse is inducing heat onto a small spot on the surface, which causes vibrations inside the material creating an surface acoustic wave pulse traveling away from its source.
The detection of the surface acoustic waves can also be achieved by optical means using a Laser-Doppler-Vibrometer, which measures the displacement of the surface with a resolution of up to two pm. By scanning an area of a specimens surface inhomogenities, changes in the microstructure or microfractures inside the material can be detected.
It is also possible to utilize this technique for the measurement of the thickness and Young’s modulus of thin films or thin layers on a substrate.
The best-known surface acoustic wave (SAW) is a seismic wave resulting from an earthquake, which may have devastating impacts on nature and humanity because of its brute forces. In a miniaturized form, this waves can be used for ingenious novel technologies.
Various applications such as sensors and actuators utilize these microscopic seismic waves.
These surface acoustic waves have proven their diverse userfulnes e.g. in biomedical applications, mobile communication, household and automotive engineering.
ISAT has extensive know-how with respect to surface acoustic wave applications. We would like to give you an insight in our work on the following pages.
Due to the rapid development in medicine and life science, the demand for novel and specific sensor and actuator concepts has increased.
They are needed for monitoring and controlling biological, biochemical and medical processes, which also have an influence on health and life quality.
ISAT is going to contribute to this development with ideas and demonstration devices and is interested in research partnerships with respect to an industrialization of such innovations.
First products are already planned: A sensor for online-monitoring of biofilm formation inside containers or tubes using surface acoustic wave technology has already been tested successfully.
In future, the influence of ultrasound on acoustic separation of cells, the phase separation of emulsions or the influence on cell metabolism or nutrient uptake shall be investigated.
Medical Systems and devices have to provide a constant level of hygiene. Therefore, biofilm development on interfaces must be monitored intensly to maintain the hygiene and prevent biofilms from growing and ensure efficiency of these systems.
Technical systems such as heat exchangers or air conditioners can be influenced in their performance due to the formation of non-removable bacterial films. Regarding the need of a cost-efficient and exact online detection method, the ISAT is able to provide innovative sensor - prototypes to optimize the disinfection cycles of medical devices to ensure the maintenance of technical facilities.
The significant advantage is the excitation of surface acoustic waves (SAW) on the outer surface of plant components or tubes and the monitoring of biofilms inside the system in order to maintain sterility. Different investigations revealed the capability of acoustic technology to monitor biofilm development in liquid filled tubes and pipes precisely and also detect other types of layers.
The basic physical principle is based on the measurement of the SAW propagation characteristics. In measurements with biofilm-substitutes, detection limits of about 5 µm layer thickness were determined. First measurements with real biofilms confirmed these results.
Due to the achieved detection limit, biofilm layers can already be recorded and removed in early stages of their growth.
Not only the human body consists of almost 70 % of water, but also in technological applications or daily life, water and other liquids are of great importance. As an example, in optical sys-tems, e.g. camera lenses, accumulation of droplets or conden-sate influence the systems efficiency negatively.
On a larger scale, e.g. on car windscreens, different types of rain sensors are used for droplet detection. Those sensors are beco-ming more and more common but their disadvantage is, that they can only monitor a small area of the windscreen. By using surface acoustic waves, which can propagate on the complete glass, it is possible to create a windscreen which is sensitive to droplets on its whole surface.
This technique can also be used for various other applications beyond the automotive sector: droplet detection on toll came-ras, in “intelligent homes”, for leakage detection onto surfaces or for monitoring other optical systems as mentioned in the beginning. Special designed ultrasonic transducers allow us to create this liquid sensitivity not only on glass, but also on other materials, e. g. metals and plastics. The technology can further be used to detect the amount and the location of liquids.
Touch applications became an inevitable and fast developing part of nowadays technology. From smartphone to domestic appliances – touchscreens and softkeys capture every touch and transfer it into a switch function.
These softkeys can be implemented on many everyday objects without changing their properties and looks. This is the reason why this technology is especially appropriate for specialized applications with particular requirements such as sterility.
The institute transferred it´s knowledge in SAW technology into a functional prototype of a touch sensitive tile.
Examples for their multifunctional uses in households are bathrooms and kitchens, where they meet the high demands regarding electrical insulation, sterility and cleaning.
Beyond private households, it is also possible to employ this technology in hospitals or nursing care facilities, where a high level of hygiene must be maintained to prevent pathogenic microorganisms and bacteria from growing.
Above all, these tiles can also be used in modern room surveillance systems to monitor interaction of persons and also for automatic alarm in case of a person lying injured on the ground or for notification of water damages.
These are only few examples for the various application possibilities, which SAW based technology offers. Beside ceramic surfaces, there are also other materials such as glass, metal and various plastics on which SAW can be generated in order to realize softkeys. Potential fields of application are almost unlimited.
Duration: 01.01.2016 bis 31.12.2020
The funded EFRE-project „InnoTerm“ focuses on the promotion of research and development partnerships with small and medium sized companies in the former Northern-Bavarian border region (Upper Franconia and northern Lower Franconia).
The ideas and issues of the companies will be directly implemented into the research work of the ISAT and shall be transformed into marketable developments and applications. An "innovation terminal" as a regional platform for a continuous transfer of technology will be established.
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Duration: 1.10.2012 bis 30.09.2014
The funded EFRE-project „Actuations“ is focused on the promotion of research and development partnerships with small and medium sized companies in the former Northern-Bavarian border region (Upper Franconia and northern Lower Franconia).
Developments and applications of actuator technologies, which have already been explored by ISAT, will be employed for the exitation of innovation impulses in the future.
Whilst technology transfer with small and medium sized companies is well-developed and established in sensor technology in this part of Bavaria, actuator technology withholds enormous development potentials which have not been exhausted yet. Additionally, sensor technologies such as microacoustics can also be used for actuation purposes.
Therefore, know-how aquired so far and facilities can be used for actuator technology as well.
Acoustic deformation of fluid surfaces
Duration: 1. August 2012 bis 31. Juli 2015
The distribution and influence of touch controlled devices has an increasing impact in everyday life. Currently, several activities in creating tactile output devices, especially for mobile phones or tablet computers, are observable. The development of a device with tactile feedback is desirable especially for blind users. The main challenge this the creation of free moldable surfaces. The effect of local, acoustic deformation of liquids, which was observed in the Institute of Sensor and Actuator Technology (ISAT), shall be further investigated in the funded “Adolis” project to develop a Braille display. The concept shall not only be used for the development of Braille displays but also in the white goods sector.
- ViewPlus Technologies, Inc.
- Seuffer GmbH&Co.KG
- Fraunhofer ISC
Charging acceleration of electrochemical energy storages by irradiation of highfreuqently ultrasonic waves
Duration: 01.10.12 – 30.09.2015
The general focus is the systematic investigation of electrochemical reactions in electrochemical energy storages e.g. lead accumulators. Furthermore the influence of kinetic procedures by targeted use of high frequently sound waves, especially surface acoustic waves will be analyzed. A strategic demand for the implementation of electromobility concepts and for the operation of decentralized electrochemical energy storage networks is the increase of capacity of such energy storages, the reduction of charging time and used energy in this process.
· Starting point: Investigations on targeted irradiation of sound in the boundary layer between electrode and electolyte where most transport limiting processes take place. Results should demonstrate if these processes can be optomized through irradiation of sound.
· Reason: Increase of energy storage capacities as well as reduction of charging time or reduction of needed energy in this process. These factors are crucial for the realization of future electromobility concepts and for the use and operation of decentralized electrochemical energy storage networks.
· Target: Development of a component for targeted irradiation of sound, tested in real life conditions and implemented in consisting accumulators in cooperation with the cooperation partner Seuffer GmbH & Co. KG. Main target is also the transfer of the acquired knowledge to other electrochemical energy storages.
· Seuffer GmbH & Co. Kg
Development of efficient electronic systems and online diagnostics functions for facilities and devices
Duration: 01.11.2012 - 31.10.2015
Pumps provide substantial energy input for pressure boosting and fluid movement which is needed for pressure and flow in the process. This actuator technology is on the one hand significant for the technical process and on the other hand the ”main consumer” of the whole electrical energy needed in the process.
To improve efficiency and minimize consumption as well as wear modern pumps have a speed governor, integrated sensor technology (pressure, differential pressure and temperature), integrated functions for optimized control and regulation in the hydraulically process and also integrated protective functions. This hydro-mechatronic character of modern pumps and pumping systems is designed with specific tools and methods for the particular components like hydraulics (pump, valve, and piping), mechanics, sensor technology, power electronics, electro mechanics, control hardware and firmware as well as PC based software for device management and system integration. An upstream request and application oriented function design plus an adequate throughout methodically and interdisciplinary system design and architecture design on this basis is missing.
Targets of this project regarding hydro-mechatronic products:
- Development of basic principles and methods for a consistent interdisciplinary model-based design - Verify the use of reconfigurable hardware in order to develop platform concepts in this domain - Ensure innovative online diagnostic procedures for pumping systems by adaption of novel sensor technologies
- KIT - Karlsruhe Institute for Technology, Institute for Information Processing Technologies (Institut für Technik der Informationsverarbeitung - ITIV)
- Martin Luther University (MLU)Halle, AG Software-Engineering
- LeiKon GmbH
- BestSens AG
- KSB AG
Intelligent bridge surveillance by neuronal-networked sensors
Duration: 01.08.2013 – 31.07.2016
The most important Central European transit country Germany faces the challenge of maintaining the efficiency of the transport infrastructure and expand it continuously. Besides the construction of new or the expansion of existing lines, the maintenance of the infrastructure plays a key role. Neuralgic buildings are mainly bridges, their preservation or their replacement results in huge costs, which has an high economically impact. Normally substantial expenses are required to ensure and maintain the availability, security and durability of bridge structures. In front of this background, it is eminent to recognize any damage or loss potentials as early as possible. The aim is to develop a system for monitoring a bridge building in real time by the help of a neural sensor data processing system using optical fiber sensors (FBG and Rayleigh system).
All sensor data are merged and processed in a suitably programmed neural network. With the help of such a "smart" control bridge it is possible to realize a self-configuring monitoring system which informs the operator in detail about the actual state of the bridge structure in real-time. This offers a significant potential for savings, because bridges can be serviced effectively. Annoying and economically expensive traffic closures may be shortened or even avoided.
- Pötzl Ingenieure GmbH
- Ci-Tec GmbH
- Karlsruhe Institute of Technology - Institute for Applied computer science