Patent attributes
A multiplexed inductive tactile sensor for measuring location and force of contact with an external object includes sense and drive electronics and an array of sensels, each having a drive coil inductively coupled with a sense coil. The array has rows and columns of sensels. Drive coils in each column are electrically connected in series and driven by an AC constant current source through an analog demultiplexer. All sense coils in each row are electrically connected in series and the induced AC voltage across the row is fed to an AC amplifier through an analog multiplexer. The amplified AC voltage is then fed to the amplitude demodulator to generate a DC signal that is dependent on the inductive coupling factor between drive coil and sense coil of a sensel that is selected by being the intersection of the active current drive column and sense row. A first deformable conductive shield layer may be disposed adjacent to a first compressible dielectric layer disposed on first side of a PCB. A second conductive shield layer and a second dielectric layer may be disposed in a similar manner on a second side of the PCB. The controller electronics are configured to measure the induced AC voltage change due to a change in inductive coupling factor between drive coil and sense coil of a selected sensel in response to an external object imparting local mechanical compression onto the first conductive shield layer and the first compressible dielectric layer.
