| abstract |
A contact sensor for detecting points on a grid where the sensor is being contacted on opposing sides by teeth surfaces or other contacting points. The sensor is especially useful for measuring dental occlusion. The contact sensor includes two sets of parallel electrodes which are each formed on a thin, flexible supporting sheet. The electrodes are separated by a thin, pressure-sensitive resistive coating such as molydenum disulphide. Two such electrode structures are oriented at approximately right angles to create a grid where the intersecting electrodes cross separated by the resistive coatings. Several arrangements of resistive coating over electrodes as disclosed. In the absence of an external force, the material between the electrodes sets provides a high resistance between intersecting electrodes. The resistance between electrode intersections changes as pressure on opposite sides of the intersection changes. The sensor output is dynamic in that the resistance will vary as external pressure is repeatedly applied and removed. The sensor may be made extremely thin and can provide high resolution capable of distinguishing between contact points separated by 0.050 inches or less. n A new circuit is provided which measures the resistance between each electrode intersection and provides an output representative of the opposing forces at the intersection. The circuit limits the maximum possible current which can flow in the sensor and provides increased resolution in measuring pressure between contacting surfaces. |