Patent attributes
A toothbrush has a handle and a treatment head mounted for movement relative to the handle against a spring force when a treatment force is applied in at least one treatment direction onto the treatment head. A treatment force measurement unit for determining the applied treatment force includes a capacitive force senor having a first electrode fixedly mounted with respect to the handle and a second electrode mounted at a distance from the first electrode. The second electrode is movably mounted with respect to the handle. A spring unit is arranged between the first and the second electrode. A control circuit determines at least one parameter indicative of the capacitance between the first and second electrodes, wherein the second electrode is mechanically coupled with the treatment head and is arranged to be moved relative to the first electrode when the treatment force is applied at the treatment head.
