Optical Interferometric Pressure Sensor

• Main Authors: BERTSCH DIETMAR, MULLIS FELIX, ANTILA JARKKO, WUEST MARTIN
• Format: Patent
• Language: English
• Published: 31.12.2009
• Subjects: MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER,MECHANICAL EFFICIENCY, OR FLUID PRESSURE; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

A pressure measuring cell has a first housing body and a membrane arranged proximate the housing body, both of ceramic. The membrane has a peripheral edge joined to the first housing body to create a reference pressure chamber. A second housing body made of ceramic material is opposite the membrane and is joined to the peripheral edge of the membrane, the second housing body together with the membrane forming a measurement pressure chamber. The second housing body has a port for connecting the pressure measuring cell to a medium to be measured. The first housing body, the second housing body and the membrane are tightly connected along the peripheral edge of the membrane in a central area of the first housing body a hole is formed, reaching through the first housing body and at least in the central region of the membrane and opposite the hole a surface of the membrane is formed as a first optically reflective area. An optical fiber is arranged and tightly fixed within the hole for feeding light onto the surface of the membrane. The end of the fiber reaches at least the surface of the first housing body and is formed as a second reflective optical area linking the surface so that between the fiber end and the reflection area an optical cavity is present which forms a measuring section for determining the level of deflection of the membrane and which is part of a Fabry-Perot Interferometer.