Method and system of one tactile sensor
View Patent ↗Methods, systems, and programing of one tactile sensor are presented. In one example, magnetic sensors containing one or more layers are formed on a base substrate for sensing a magnetic field generated by one ferromagnet present in close proximity to the magnetic sensors. The ferromagnet is embedded in an elastomer matrix. When an external force is applied to the elastomer matrix, it deforms and displaces the ferromagnet. As a result, the magnetic field generated by the ferromagnet changes. This change is sensed by the magnetic sensors to in turn quantify the applied force.
1. A method for detecting contact or touch, comprising:
the detection of a first level of magnetic field via a device comprising a substrate with a plurality of magnetic sensors configured for sensing a magnetic field generated by a ferromagnet in proximity to the magnetic sensors;
the coating of the magnetic sensors with an elastomer matrix with the ferromagnet embedded in it;
the displacement of the ferromagnet due to the deformation of the elastomer matrix upon contact or touch with an external object;
the detection of a second level of magnetic field via the device;
and the calculation of the displacement of the ferromagnet using a predefined algorithm.
2. The method of claim 1 , wherein the elastomer matrix has a basecoat part underneath the ferromagnet, and an overcoat part above the ferromagnet, while the basecoat and overcoat can be made of the same or different materials.
3. The method of claim 1 , wherein the ferromagnet is formed using photolithography-deposition process, which comprises:
coating the elastomer basecoat with a seed layer;
coating the seed layer by photoresist and applying standard photolithography approach to form holes with desired shape and depth;
depositing ferromagnetic material into the holes;
and lifting off the photoresist to prepare for coating of the elastomer overcoat.
4. The magnetic sensors according to claim 1 , wherein the plurality of sensors comprises giant magnetoresistance (GMR) sensors, anisotropic magnetoresistance (AMR) sensors, tunneling giant magnetoresistance (TGMR) sensors, and Hall sensors, or a combination of them.
5. The substrate according to claim 1 , wherein the substrate comprises rigid materials such as silicon, GaAs, AlTiC, or flexible materials such as polyimide, polyethylene terephthalate (PET), polyethylene-2,6-naphthalate (PEN), polydimethyl siloxane (PDMS), etc.
6. The elastomer matrix according to claim 1 , wherein the elastomer matrix comprises natural rubbers, styrene-butadiene block copolymers, polyisoprene, polybutadiene, ethylene propylene rubber, ethylene propylene diene rubber, silicone elastomers, fluoroelastomers, polyurethane elastomers, and nitrile rubbers, etc.
7. The ferromagnet according to claim 1 , wherein the ferromagnet comprises soft magnetic materials such as iron, cobalt, nickel, and their alloys, or permanent magnetic materials such as NbPeB, SmCo alloys, PePt, CoPt, etc.
8. The ferromagnet according to claim 1 , wherein the ferromagnet comprises shapes of circular, rectangular, square, etc., if viewed from the top.