US Patent 9983171 Aerospace transparency having moisture sensors

A transparency, e.g. an aircraft laminated windshield, includes one or more moisture sensors to monitor moisture penetration to monitor performance of the moisture barrier. At least one of the moisture sensors includes a dielectric between and in electrical contact with two electrically conductive electrodes. Alternating electrical current is applied to the electrodes to measure the complex impedance (ohms) of the dielectric to determine the amount of moisture within the laminated windshield in the area of the moisture sensor. With the information provided by the moisture sensors performance of the windshield is available to schedule timely repair or replacement of the windshield that is performing outside of acceptable limits.