Quasi-monolithic silicon load cell for loads up to 1000 kg with insensitivity to non-homogeneous load distributions

In this paper, a micromachined silicon load cell (force sensor) is presented for measuring loads up to 1000 kg. The sensitive surface of 1 cm2 contains a matrix of capacitive sensing elements to make the load cell insensitive to non-homogeneous load distributions. The load cell has been realized and tested. Measurements on a packaged device show an accuracy of 0.2% of full scale limited by the measurement electronics. An accuracy of 0.03% or better is expected to be feasible. The design can be easily adapted for higher loads by increasing the chip area or using multiple chips in a single package.