Rethink Sensor Technology –
Discover a new sensor technology
Individual design, adjustable sensor type and shape, as well as ultra thin and flexible structure – all allow an integration into application could not be reached before.
What is a foil sensor and how are the sensors manufactured?
Printed electronics is on everbody's lips. It is no rocket science to apply conductive structures additively on a substrate, but there is more to a sensor than only a strip conductor. We at accensors realize foil sensors by bringing together a varierty of materials and elements. For this we make use of differnt processes such as printing, dispensing, pick and play as well as additive or ablatable processes. A good example is the multilayer structure, where differnet matterials are stacked up on top of each other. The sensor capacities of a multilayer structure then result from the mechanical impact on the structure (e.g. a capactive pressure sensor) or the change in phsyical properties (e.g. resistance change in a tempertaure sensor) or electromechanical effects, which emerge at specific sensitive electrodes.
This is accensors major know-how, which we describe as “sensor-functionalzation“.
What is a foil sensor?
A foil sensor is an electrofunctional element, which is stacked on a foil substrat (usually flexible and made from synthetic material) through an additive process. The electrofunctional element consists of at least the electrical supply lines and the sensor element or the actuator element or the emitter element. The design of the foil substrate can be freely chosen. The way a sheet of paper is cut to size, the foil substrate can also be cut to any shape. The layout is characterized by the path of the electrical supplies as well as the position and the size of the sensor-, actuator- or emitter element on the contour foil substrate.
Additive manufacturing of a foil sensor (Example)
The foil substrate is the base of this structure. According to the requirements it can be decided if plastic material such as PI, PET, PE, PU or others, is used. Even fabric and other materials can be chosen.
The foil sensor can be build with either one individual detection parameter or multiparametric or even as a sensor array. For different sensors different measurement procedures are provided.
The overall structure can be build not only flexible but also very thin (down to 30µm total thickness) in all areas. State-of-the-art process technology is applied for the integration of the conducting paths, the corrosion protection of the pins, the placement of the sensor unit and lagging. If required additional layers can be integrated – so called “multifoil system”.
Foil sensors are not restricted to a planar shape. It is feasible to model the foil material into three-dimensional shapes (3D-object). This is conducted through thermal reshaping, also known as thermofroming. During this procedure the foil substrate is shaped into a three-dimensional form by using high temperatures and pressure. The form remains unchanged after cooling down.
Hereby, it is possible to directly integrate the foil sensors into geometrical forms and objects without coupling further components with the foil sensor.
Another option to integrate multiple sensors on one foil subtrate is by using sensorarrays. The difference between multiparametric sensors and sensorarrays is, that former arranges multiple different sensors, and that latter arranges multiple same sensors. The sensor units can be placed on the foil substrate either in an even matrix or freely, without a specific pattern. With the sensorarray you can detect differences of the measurand at differnt measuring locations on a more accurate level. This is the senorarray's great advantage.
In contrast to multilayer, the multifoil system stacks multiple foil substrates on top of each other. This leads to the advantage of having a variety of functions above each other instead of next to each other.
In a PCR (polymerase chain reaction) high temparutres are required for denaturation. This is done by a heat emitter (a heating coating), which is on the first foil layer. Modficated electrodes to catch the target molecules are applied on the second layer. Hence, this layer is placed directly above the heating coating but is seperated by a foil layer. A level sensor on the third foil layer completes the multifoil system.
The foil sensors from accensors do not only enable the integration of sensors, actuators, emitters and their supplies on a flexible foil substrate. They also allow fludic canals to be integrated directly with the foil sensor. This facilitates the extraction of fluids or the addition of media at diffenernt positions.
We at accensors offer two options to realize microfluidic canals in or on a foil sensor:
A) Micro channel structuring via laser
B) Microcanals via multifoil-systems