Fidelica, Microsystems, Inc.

Springworks, LLC

Christopher Stoessel

Shiva Prakash

Srinivasan K Ganapathi

Randolph S Gluck

Keith T Deconde

Steve Hovey

A method of making an integrated texture sensor for sensing a texture is described. In one embodiment, the method is directed to a sensor that that is protected from external contaminating particulates and will self-equalize using air from outside the sensor. Further combinations of such protection among various membrane switches, in combination with various types of membranes, is described. In another embodiment, a method of making a skin-texture sensor for sensing a skin texture having a plurality of ridges and a plurality of valleys is described, such that when completed, applying a ridge of the texture to a membrane switch will cause flexure of the membrane resulting in a contact between the lower electrode and the upper electrode, the contact establishing an electrical communication between said one of the row lines and said one of the column lines, whereas disposing a valley of the texture over said each membrane switch will not result in the contact between the lower electrode and the upper electrode.

Fingerprint sensors using membrane switch arrays

A sensor for identifying fingerprints or other skin textures includes an array of cells each including a membrane switch. Each switch includes a fixed lower electrode disposed on a chip substrate, and a flexible membrane disposed over the lower electrode and capable of flexing downward to establish electrical contact between the lower electrode and an upper electrode. The upper electrode can form the membrane itself or a layer of the membrane, or can be attached to other membrane layers. Switches situated underneath skin ridges change state (e.g. are closed) by the applied pressure, while switches underneath skin valleys remain in their quiescent state (e.g. open). Adjacent switch chambers are connected by fluid tunnels which allow the passage of air between the chambers. Each chamber is substantially closed to the exterior of the sensor, such that particles from the environment cannot contaminate the switch contact surface defined between the switch electrodes. The cells are preferably not hermetically sealed, such that the pressure within the chamber interiors can stay equal to the external (atmospheric) pressure in varying environmental conditions. The membrane design of the cells according to the preferred embodiment allows improved sensor robustness, enhanced resistance to impact forces, decreased vulnerability to particle contamination, and reduced inter-cell crosstalk.

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Bodega Bay, CA, United States of America

Christopher Stoessel