Cylinder Layout for Silicone Layer in Force Sensor
Publication Date: 2014-Jun-27
The IP.com Prior Art Database
Proximity sensor devices (also commonly called touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface in which input objects can be detected. The proximity sensor can be used to enable control of an associated electronic system. Some proximity sensors have been implemented with additional ability to detect and determine force applied to a surface of the sensor. For example, a capacitive sensor having several arrays of sensor electrodes may provide force information about user input in response to a change in capacitance between a layer of receiver electrodes and transmitter electrodes. The layers of receiver and transmitter electrodes may be separated by a compressible medium. Touch and force sensing are achieved by splitting up the receivers in two layers. One layer of receivers is located above the transmitters and senses capacitive touch, as is the case with other traditional sensors. The second layer of receivers is located below the transmitters. A compressible medium is placed between the transmitters and the second layer of receivers. When the sensor is pressed, the compressible medium is compressed and the capacitance between receivers and transmitters changes, thusly allowing capacitive force sensing. In some embodiments, an elastic silicone rubber sheet is used as the compressible medium that provides for sufficient deflection of the input surface for the measurement of a change in capacitance due to force. As described herein, a layout of a hexagonal grid and spacing between cylinders can increase force sensitivity and improve sensing linearity as well as overall mechanical stability of the force sensor.